2023年12月8日发(作者：竭香巧)

SERVICE MANUALColor Inkjet PrinterEpson WF-3720 SeriesCONFIDENTIALSEMF16-010Notice:All rights reserved. No part of this manual may be reproduced, stored in a retrieval system, or transmitted in any form or

by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of

SEIKO EPSON CORPORATION.All effort have been made to ensure the accuracy of the contents of this manual. However, should any errors be

detected, SEIKO EPSON would greatly appreciate being informed of them.The contents of this manual are subject to change without notice.The above not withstanding SEIKO EPSON CORPORATION can assume no responsibility for any errors in this

manual or the consequences is a registered trademark of SEIKO EPSON :Other product names used herein are for identification purpose only and may be trademarks or registered

trademarks of their respective owners. EPSON disclaims any and all rights in those ght 2017SEIKO EPSON CORPORATIONP・CS Quality Assurance DepartmentConfidentialSafety PrecautionsAll safety procedures described here shall be strictly adhered to by all parties servicing and maintaining this

Strictly observe the following cautions. Failure to comply could result in serious bodily injury or loss of disconnect the product from the power source and peripheral devices when servicing the product or

performing performing works described in this manual, do not connect to a power source until instructed to do so.

Connecting to a power source causes high voltage in the power supply unit and some electronic components

even if the product power switch is off. If you need to perform the work with the power cable connected to a

power source, use extreme caution to avoid electrical GStrictly observe the following cautions. Failure to comply may lead to personal injury or loss of wear protective goggles for disassembly and reassembly to protect your eyes from ink in working. If

any ink gets in your eyes, wash your eyes with clean water and consult a doctor using compressed air products; such as air duster, for cleaning during repair and maintenance, the use

of such products containing flammable gas is TIONSStrictly observe the following cautions. Failure to comply may lead to personal injury or damage of the s on Epson product should be performed only by an Epson certified repair work should be performed on this product by persons unfamiliar with basic safety knowledge required for

power rating of this product is indicated on the serial number/rating plate. Never connect this product to

the power source whose voltages is different from the rated e malfunctioning components only with those components provided or approved by Epson;

introduction of second-source ICs or other non-approved components may damage the product and void any

applicable Epson capacitors on the Main Board may be electrically charged right after the power turns off or after driving

motors which generates counter electromotive force such as when rotating the PF Roller or when moving the

CR Unit. There is a risk to damage the Main Board if the Head FFC is short-circuited with the capacitors on

the Main Board electrically charged, therefore, after the power turns off or after motors are driven, leave the

printer untouched for approximately 30 seconds to discharge the capacitors before starting disassembly/ prevent the circuit boards from short-circuiting, be careful about the following when handling FFC or

cables.When handling FFC, take care not to let the terminal section of FFC touch metal parts.When connecting cables/FFC to the connectors on circuit boards, connect them straight to the connectors to avoid

slant order to protect sensitive microprocessors and circuitry, use static discharge equipment, such as anti-static

wrist straps, when accessing internal not tilt this product immediately after initial ink charge, especially after performing the ink charge several

times. Doing so may cause ink to leak from the product because it may take some time for the waste ink pads

to completely absorb ink wasted due to the ink touch the ink or wasted ink with bare hands. If ink comes into contact with your skin, wash it off with

soap and water immediately. If you have a skin irritation, consult a doctor disassembling or assembling this product, make sure to wear gloves to avoid injuries from metal parts

with sharp only recommended tools for disassembling, assembling or adjusting the e the specified torque when tightening extremely careful not to scratch or contaminate the following parts.Nozzle plate of the printheadCR ScalePF ScaleCoated surface of the PF RollerGearsRollersLCDScanner SensorExterior use oil or grease other than those specified in this manual. Use of different types of oil or grease may

damage the component or give bad influence on the printer the specified amount of grease described in this the specified adjustments when you disassemble the cleaning this product, follow the procedure described in this transporting this product after filling the ink in the printhead, pack the printer without removing the

ink cartridges in order to prevent the printhead from drying sure to install antivirus software in the computers used for the service support the virus pattern file of antivirus software disassembling/reassembling this product, if you find adhesive power of the double-sided tape which

secure the parts or FFC is not enough, replace the tape with new one and attach it correctly to the specified

points where the parts or FFC should be otherwise specified in this manual, the labels attached on the returned product should be transferred to

the corresponding attachment positions on the new one referring to the labels on the returned entialAbout This ManualThis manual, consists of the following chapters, is intended for repair service personnel and includes information

necessary for properly performing maintenance and servicing the R 1. TROUBLESHOOTINGDescribes the step-by-step procedures for the R 2. DISASSEMBLY / REASSEMBLYDescribes the disassembly/reassembly procedures for main parts/units of the product, and provides the

standard operation time for servicing the R 3. ADJUSTMENTDescribes the required adjustments for servicing the R 4. MAINTENANCEDescribes maintenance items and procedures for servicing the R 5. REFURBISHMENTDescribes refurbishing work of the product and its R 6. APPENDIXProvides the following additional information for reference:Connector DiagramProtection for TransportationSymbols Used in this ManualVarious symbols are used throughout this manual either to provide additional information on a specific topic or

to warn of possible danger present during a procedure or an action. Pay attention to all symbols when they are

used, and always read explanation thoroughly and follow the tes an operating or maintenance procedure, practice or condition that, if not strictly observed,

could result in serious injury or loss of tes an operating or maintenance procedure, practice, or condition that, if not strictly observed,

could result in bodily injury, damage or malfunction of indicate an operating or maintenance procedure, practice or condition that is necessary to

accomplish a task efficiently. It may also provide additional information that is related to a specific

subject, or comment on the results achieved through a previous Chapter 2 “Disassembly/Reassembly”, symbols other than indicated above are used to show additional

information for disassembly/reassembly. For the details on those symbols, see "2.3 Disassembly/Reassembly

Procedures (p47)".ConfidentialRevision StatusRevisionABDate of IssueMar 10, 2017May 26, 2017First ReleaseRevised□Chapter 2　■　Made change in "2.3 Disassembly/Reassembly Procedures (p47)"　　・　Made change in "2.3.3.1 Disassembly/Reassembly Flowchart (p49)"　■　Made change in "2.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit

(p54)"　　・　Made change in " Housing Upper (p54)"□Chapter 3　■　Made change in "3.2 Adjustment Program (p64)"　　・　Made change in "3.2.2 Adjustment and Inspection List (p64)"Revised□ Chapter 1　■ Made change in "1.3 Fatal Error Code List (p13)"　　・ Made change in "1.3.2.5 Printer (Head/CSIC) (p21)"　　　 “HCS error” has been added.□ Chapter 2　■ Made change in "2.1 Overview (p38)"　　・ Made change in "2.1.4 Standard Operation Time for servicing the product (p42)"　　　 “Stacker Support Front Assy” has been added.　■ Made change in "2.3 Disassembly/Reassembly Procedures (p47)"　　・ Made change in "2.3.3.1 Disassembly/Reassembly Flowchart (p49)"　　　 “Stacker Support Front Assy” has been added.　■ Made change in "2.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit (p54)"　　・ Made change in " SCN Hinge Assy (p54)"　　・ Made change in " Printer Mechanism (p56)"　　・ " Stacker Support Front Assy (p57)" has been added.　■ Made change in "2.5 Routing FFCs/cables (p58)"　　・ Made change in " Panel Assy (p58)"　　・ Made change in " ADF/SCN Unit (p58)"　　・ Made change in " Ink System (p58)"　　・ Made change in " Power Supply Unit (p58)"　　・ Made change in " Head FFC/CSIC FFC (p59)"　　・ Made change in " Speaker Cable (p60)"□ Chapter 3　■ Made change in "3.2 Adjustment Program (p64)"　　・ Made change in "3.2.2 Adjustment and Inspection List (p64)"　　・ Made change in "3.2.3 Details of the Adjustment Program (p69)" Made change in “PTS delay adjustment”.　■ Made change in "3.3 Mechanism Adjustment / Check (p76)"　　・ Made change in "3.3.1 Checking the Platen Gap (p76)"□ Chapter 5　■ Made change in "6.2 Protection for Transportation (p91)"　　・ "6.2.5 Preventing the shipping Liquid from leakage from Printhead (p95)" has been ptionCDecember 15,

2017ConfidentialEPSON WF-3720 SeriesRevision CContentsChapter 1 101.1. 101. 121.3Fatal Error 131.3.1Displaying the Fatal 131.3.2Fatal 141.3.2. 141.3.2.2Printer (CR)............................................................................................................................................ 171.3.2.3Printer (PF)............................................................................................................................................ 181.3.2.4Printer (I/S)............................................................................................................................................ 201.3.2.5Printer (Head/CSIC).............................................................................................................................. 211.3.2.6Printer (Others)...................................................................................................................................... 221.3.2. 231.4Service 241.4.1Status . 27Chapter 2 Disassembly/ 382. 382. 382.1.3Locations of the 392.1.4Standard Operation Time for servicing 422.2Common cautions when disassembling/reassembling 452.3Disassembly/ 472.3.1Functional differences between models and 472.3. 482.3.2.1Disassembly/ 492.4Detailed Disassembly/Reassembly Procedure for each 542.5Routing 58Chapter 3 Adjustment3. 623. 643.2. 643.2.2Adjustment and 643.2.3Details of the 693.3Mechanism Adjustment / 763.3.1Checking the . 763.3. 763.3.1.. 783.3.2MAC 79Chapter 4 . 814.1.1Cleaning the 817ConfidentialEPSON WF-3720 SeriesRevision C4.1.2Cleaning the Exterior Parts/inside of 834.2.1Lubrication Points 84Chapter 5 885.1. 88Chapter 6 Appendix6. 906.2Protection 916.2.1Securing the 916.2.2Securing the SCN/ 926.2.3Securing the 936.2.4Securing the ADF 946.2.5Preventing the shipping Liquid from leakage 958ConfidentialCHAPTER1TROUBLESHOOTINGConfidentialEPSON WF-3720 SeriesRevision C1.1 TroubleshootingThis section describes the troubleshooting workflow.1.1.1 Troubleshooting WorkflowThe following page describes the troubleshooting workflow. Follow the flow when troubleshooting problems.This flowchart is compiled based on the following contents.

•Our experience regarding the quality problem•ESK’s repair data•Printer Mechanism specification for WF-3720 SeriesIf the reason for the return is evident, first check the phenomenon user claims recurs,

then proceed to the hat is returned reason?Turn on the printerPrinter failure onlyADF/Scanner

unit failureCopy an imageDoes printer turn on the

power?YesNo1(p 11)Is scanning operation

finished without

trouble?YesNo5(p 11)Is Power-on sequence

finished without error?YesStandby conditionNo2(p 11)ADF failure?YesNoPrint check patternCopy an image by ADFIs printing operation

finished without error?YesNo3(p 11)Is ADF operation finished

without trouble?YesNo6(p 11)Is printing operation

finished without trouble?YesNo4(p 11)Finish**:In case of “Not Trouble Found”, check fatal error eshooting Workflow (1)TroubleshootingTroubleshooting10ConfidentialEPSON WF-3720 SeriesRevision C1The power-on

sequence does not

start (p 10)2Error is indicated during

power-on sequence (p 10)No Power*[Presumable Cause]•Power Supply Unit

damage•Main Board damage•Panel Unit damage[Major Troubleshooting]•Power Supply Unit

replacement•Main Board

replacement•Panel Unit replacementFatal error Please refer to " 1.3 Fatal Error

Code List (p13)" for

nance error[Occurrence Condition]This error occurs when

maintenance counter in

EEPROM exceeds the specified

value.[Major Occurrence Timing]•Power-on timing•Print start timing•Paper eject timing•Cleaning timing•Ink cartridge replacement

timing[Major Troubleshooting]•Replace Maintenance Box•Paper Guide Lower Porous

Pad replacement•Maintenance counter reset

(only Paper Guide Lower

Porous Pad)Paper Jam errorThis error occurs when printing

the nozzle check pattern. please

refer to " Paper Jam error".

Ink End error[Occurrence Condition]This error occurs when ink in Ink

cartridge is empty.[Major Occurrence Timing]•Power-on timing•Print start timing•Print timing•Cleaning timing•Ink cartridge replacement

timing[Major Troubleshooting]Ink cartridge replacement[NOTE]If an error occurs during printing,

the page where the error occurred is

skipped and the printing resumes

from the next cartridge detection error[Occurrence Condition]This error occurs when Ink

cartridge data is incorrect or Ink

cartridge is not recognized

correctly.[Major Occurrence Timing]•Power-on timing•Print start timing•Cleaning timing•Ink cartridge replacement timing[Major Troubleshooting]•Remove and reinstall Ink

cartridge.•Ink cartridge replacement•CSIC Terminal replacement•CR Contact Module

replacement•Head FFC replacement•Main Board replacementNo Ink cartridge error[Occurrence Condition]This error occurs when Ink

cartridge is not installed.[Major Occurrence Timing]At power-on[Major Troubleshooting]Install Ink cartridgeCR fixing material error[Occurrence Condition]When the printer moves to the

80-digit side during the power-on sequence before initial ink

charge, the printer detects

foreign material.[Major Occurrence Timing]Power-on timing(before initial ink charge)[Major Troubleshooting]Remove the CR fixing material,

and install the ink cartridge.* : If the printer can turn on but turns

off right away, the protection

circuit may cut off the power due

to an error such as a circuit

failure.3Error is indicated during printing nozzle check pattern (p 10)4Problems related to print result or during printing (p 10)5Scanning cannot be

performed

successfully (p 10)6ADF does not

operate

normally (p 10)Paper Jam error[Occurrence Condition]This error occurs when top/bottom of

paper is not detected by PE Sensor in the

specified steps of paper feeding

operation correctly.[Major Occurrence Timing]•Power-on timing•Paper loading timing•Paper eject timing•Duplex print timing[Major Troubleshooting]1Remove the jammed paper by

opening Scanner Unit or Printer

Cover.2Push “Start” button.3If not resolved by 2), check the

following.•Foreign material, bits of paper•Part come-off•PE Sensor Lever•PE Sensor•Float of Paper Guide Front Porous

Pad•Main Board•PW Sensor[NOTE]* If an error occurs during printing, the

page where the error occurred is skipped

and the printing resumes from the next

page.* If an error occurs during duplex

printing, the following are performed.•If an error occurs during the front

face of duplex printing, the page

where the error occurred and the

next page are skipped and the

printing resumes from the page

after the next.•If an error occurs during the back

face of duplex printing, the page

where the error occurred is skipped

and the printing resumes from the

next Paper error[Occurrence Condition]This error occurs when top of

paper is not detected by PE Sensor

in the specified steps of paper

loading operation correctly.[Major Occurrence Timing]Paper loading timing[Major Troubleshooting]1Put paper in cassette and push

“START” button.2If a paper stops before reaching

PE Sensor, remove it and

check the paper condition.3A)If no damage on the paper, set edge guide correctly after putting paper in cassette and push “PRINT” button again.B)If damage on the paper, check foreign materials / parts come- off / parts transformation in paper path.4If not resolved by 3-A) & 3-B),

check the following.•Pickup Roller•Duplex Unit•PE Sensor Lever•Main Board•PF Motor•Cassette AssyDouble Feed error/Stack col-lapsed error[Occurrence Condition]This error occurs on the following

cases.•A paper is ejected without

printing during paper loading

operation.•Actual paper length is longer

than theoretical one.

[Major Occurrence Timing]Paper loading timing[Major Troubleshooting]•Set the paper again.•PE Sensor Lever replacement•PE Sensor replacement•PW Sensor replacement•Main Board replacement[NOTE]This error occurs only for manual

duplex Size Unmatch error[Occurrence Condition]This error occurs when actual

paper size is not matched to

theoretical one.[Major Occurrence Timing]•Duplex print timing•FAX data print timing[Major Troubleshooting]1Put correct sized paper in

cassette, and push “START”

button.2If not resolved by step 1),

check the following points.•PE Sensor Lever•PE Sensor•PW Sensor•Main BoardNo Paper Cassette error[Occurrence Condition]This error occurs if one of the

cassettes is not installed.[Major Occurrence Timing]Paper loading timing (Front loading)[Major Troubleshooting]Install the Cassette Printing[Phenomenon]•Poor printing quality•Ink stain on paper•Dot missing•Paper eject without printing[Presumable Cause]•Driver / Panel mis-setting•Contamination of CR scale•Contamination of Printhead

Cover•Printhead damage•Ink clogging of Printhead•Contamination on Cap Unit /

Wiper of Ink system Assy•Ink system Assy damage•Float of Paper Guide Front

Porous Pad•Narrow PG•PE Lever damage•PE Sensor damage•PW Sensor damage[Major Troubleshooting]•Driver / Panel re-setting•CR Scale replacement•Printhead cover cleaning•Printhead cleaning•Ink cartridge replacement•Printhead replacement•Rubber cleaning of Cap Unit of

Ink system Assy•Ink system Assy replacement•Paper Guide Front Porous Pad

re-installation•PG readjustment•Printer Mechanism

replacement•PE Lever replacement•PE Sensor replacement•PW Sensor replacement•Main Board replacementPoor Paper Loading[Presumable Cause]•Use of 3rd party media•Edge guide mis-setting•Foreign material•Part come-off•Contamination of paper feed

roller (Duplex Unit)

•Cassette Assy damage•Pickup Roller deterioration,

contamination•Contamination of PF roller[Major Troubleshooting]•Recommendation of EPSON

media•Edge guide re-setting•Foreign material removal•Part re-installation•PF Roller replacement•Cassette Assy replacementAbnormal Noise[Presumable Cause]•Foreign material•Insufficient grease•Gear damage[Major Troubleshooting]•Foreign material removal

•Lubrication of grease•Gear replacementScanner failure[Presumable Cause]•Contamination of Scanner

Glass•Contamination of Document

Pad•CIS Unit bonding failure•CIS Unit damage•Scanner Motor damage[Major Troubleshooting]•Scanner Glass cleaning•Document Pad cleaning•Document Pad replacement•Scanner Unit replacementADF failure[Phenomenon]•No paper feed•Double feed•Paper jam•Paper skew[Presumable Cause]•Wear of Pickup Roller•Wear of ADF Pad Assy•Gear damage•Scanner Motor damage•Contamination of Scanner Glass•ADF Paper Support Assy

damage•Foreign material•ADF Cover Assy damage•Wear of EJ Roller•ADF Sensors damage[Major Troubleshooting]•ADF Cover Assy replacement•ADF Pad Assy replacement•Scanner Glass cleaning•ADF Paper Support Assy

replacement•Foreign material removal•Scanner Unit replacement•ADF Unit replacementFigure eshooting Workflow (2)Troubleshooting11ConfidentialEPSON WF-3720 SeriesRevision C1.2 Power-On SequenceThis section describes the power-on sequences for this product. The preconditions are as follows.Normal power-on sequence (See Table 1-1.)Turning on the printer after turning it off without an error and the power was turned off normally at the previous

shut l ink charge has finished and every cartridge has sufficient paper on the paper Printhead is capped by the cap of the Ink Lock is engaged nance error recovery has never been -on ead initialization*lizes the Printhead, and inspect the Unit/Cap Unit movement

and position*1㻤㻜㻯㻾㻌㼁㼚㼕㼠㻴㻼㻜㻯㻾㻌㻸㼛㼏㼗 ink overflow the waste ink counter if the waste ink overflow is occurring.㻤㻜㻴㻼㻜g the home CR Unit moves to the 0-digit side slowly and confirms it touches the Right regarding the position where the CR Unit touches the Right Frame as the specified distance from the origin, the

home position is determined. Thereafter, the position of the CR Unit is monitored based on the information

provided by the CR Encoder CR Unit slowly moves to its home position.㻤㻜㻴㻼㻜㻤㻜㻴㻼㻜㻤㻜㻴㻼㻜 temperature operation sequence*es the CR CR Unit moves back and forth between near the Home Position and near the Left Frame for two times.㻤㻜㻴㻼㻜㻤㻜㻴㻼㻜ing ink cartridge and initializing ink system* check the operation of the PIS Sensor, the CR Unit moves back and forth from around the CR lock to the middle

of the printer 2 times while passing over the PIS Sensor.㻤㻜㻴㻼㻜 lock setting

Cap rises to set the CR lock.

㻤㻜㻴㻼㻜Note*1:The conditions of the CR lock are as :CR lock is setWhite:CR lock is released*2:If it cannot be initialized, the fatal error occurs.*3:Executed when the detected temperature is under 5 oC (41oF) by the thermistor on the Printhead.*4:The cleaning or empty suction operation may occur depending on eshootingPower-On Sequence12ConfidentialEPSON WF-3720 SeriesRevision C1.3 Fatal Error Code ListThis section describes how to check the fatal error code, description, and the possible causes.1.3.1 Displaying the Fatal Error CodeThe fatal error code is stored in the EEPROM on the Main Board and can be read out using the Adjustment

Program. This product displays a printer fatal error code automatically on the panel LCD when a printer fatal

error display screen imageError CodeFigure ying the Fatal Error CodeTroubleshootingFatal Error Code List13ConfidentialEPSON WF-3720 SeriesRevision C1.3.2 Fatal Error CodeThis section describes the fatal error code and the possible cause for this product." ADF/Scanner (p14)"" Printer (CR) (p17)"" Printer (PF) (p18)"" Printer (I/S) (p20)"" Printer (Head/CSIC) (p21)"" Printer (Others) (p22)"" System Error (p23)"1.3.2.1ADF/ScannerError

codeError namePossible causeThe scanner CR could not return to its or disengaging of wheel train of the

drive aging, fraying, jumping of the timing beltFailed to read the white standard/home nection, break, skew or damage of the

scanner e of the CIS e of the scanner e of the main boardThe scanner CR cannot completely reach the home

(left side) or disengaging of wheel train of the

drive mechanismFailed to read the scanner or skew of the scanner e of the CIS e of the scanner e of the main boardThe scanner CR cannot completely reach the

opposite side of the home (right side)

or disengaging of wheel train of the

drive mechanismFailed to read the scanner or skew of the scanner e of the CIS e of the scanner e of the main boardOverload of the scanner drive mechanismFailure of the scanner motor

100020Measurement

errorConfirmation the document cover opened, turn the

power if the CIS moves to the left to read

the white standard/home if the CIS's emission color is white

(not greenish, reddish, or bluish).If the light does not look like white, check

the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new the document cover opened, turn the

power if the CIS (CR) reaches (comes in

contact with) the left the wheel train of the drive

mechanism for the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new the document cover opened, turn the

power if the CIS (CR) reaches (comes in

contact with) the right the wheel train of the drive

mechanism for the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new if the CIS (CR) moves or not.1)Check the timing belt for fraying or

looseness.2)Check the wheel train of the drive

mechanism for e the scanner unit with a new e the main board with a new the color of the LED at the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new tor

No.100016HP detection

failureMain boardCN804CN801100017Contact

detection

distance

exceededMain boardCN804CN801100018Opposite side

contact

detection

distance

exceeded errorMain boardCN804CN801---100032LED light

failureFailure of the CIS LED light (RGB)nection, break, skew or damage of the

scanner e of the CIS e of the main boardMain boardCN801TroubleshootingFatal Error Code List14ConfidentialEPSON WF-3720 SeriesError

codeError namePossible causeNo jammed paper is remaining but the sensor does

not turn e of the ADF PE e of the cableJammed paper is remainingThe paper feed rollers and paper conveying rollers

slip too muchAt power-on, during paper feed, during scanningRevision CConfirmation the Cover,Paper Guide,LD,ADF and

check if paper exist or the Document Support ADF and

check if paper exist or the ADF and check if paper exist or

if the paper sensor lever moves up

and e the ADF unit with a new e the scanner unit with a new e the main board with a new the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new tor

No.100054Paper jam errorMain boardCN802100065FB PID excess

speed errorFailed to read the scanner ination of the scanner encoder or skew of the scanner e of the scanner encoder sensorFailure of the scanner motor e of the main boardOperation failure of the scanner scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner ination of the scanner or skew of the scanner e of the scanner encoder e of the main boardThe scanner motor did not scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the CR motor ination of the scanner or skew of the scanner e of the scanner encoder e of the scanner motor

e of the main boardThe scanner motor did not scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner motor ination of the scanner or skew of the scanner e of the scanner encoder e of the scanner motor

e of the main boardThe scanner motor stopped running in the middle of

the scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner motor ination of the scanner nection, break, skew or damage of the

scanner e of the scanner encoder e of the scanner motor

e of the main boardMain the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new one.100066FB PID reverse

errorMain the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100067FB PID lock

the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100068FB PID

acceleration

lock the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100069FB PID excess

load errorTroubleshootingFatal Error Code List15ConfidentialEPSON WF-3720 SeriesError

code100070Revision CPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new nameFB PID driving

time errorConnector

No.---Malfunction or crash of the firmwareFailed to read the scanner ination of the scanner encoder or skew of the scanner e of the scanner encoder sensorFailure of the scanner motor e of the main boardOperation failure of the scanner scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner ination of the scanner or skew of the scanner e of the scanner encoder e of the main boardThe scanner motor did not scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the CR motor ination of the scanner or skew of the scanner e of the scanner encoder e of the scanner motor

e of the main boardThe scanner motor stopped running in the middle of

the scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner motor ination of the scanner nection, break, skew or damage of the

scanner e of the scanner encoder e of the scanner motor

e of the main boardMalfunction or crash of the firmware100073FB BS+ excess

speed errorMain the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new one.100074FB BS+

reverse errorMain the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100075FB BS+ lock

the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100077FB BS+ excess

load error100078FB BS+

driving time

the printer off and back it the error still occurs after the restart,

replace the main board.---TroubleshootingFatal Error Code List16ConfidentialEPSON WF-3720 SeriesRevision C1.3.2.2Printer (CR)Error

code000020Error nameCR PID

driving time

errorPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main that no obstacle exist in the CR

motion the CR lock and ink system for any

the timing belt for fraying or

the load applied to the CR by

moving it by if the lubricant on the CR shaft is the CR drive the CR encoder scale if it is

e the CR motor with a new e the main board with a new the CR encoder scale if it is

the FFC of the CR e the CR encoder sensor with a new

e the main board with a new that no obstacle exist in the CR

motion range.

the CR lock and ink system for any

the timing belt for fraying or

the CR encoder scale if it is

the CR encoder FFC or the

e the CR encoder sensor with a new e the main board with a new that no obstacle exist in the CR

motion range.

the CR by hand to see if it moves

smoothly without getting the timing belt for fraying or

the CR encoder scale if it is

the connector and the CR encoder

FFC for e the CR encoder FFC with a new the connector of the CR e the CR motor with a new e the main board with a new that no obstacle exist in the CR

motion range.

the CR lock and ink system for any

the timing belt for the CR encoder scale if it is

the connector of the CR encoder

e the CR motor with a new e the main board with a new tor

No.---Malfunction or crash of the firmwareThe CR motor stopped running in the middle of the

CR was stopped by;•Obstacles such as jammed paper•Overload of the mechanism•Interfere with the ink system•Disengaging, fraying, jumping of the timing belt•Crack or disengaging of the gear, or the APG

lever interferes with the CRFailed to read the CR ination of the CR encoder e of the CR motor (not completely broken)e of the main boardFailed to read the CR ination of the CR encoder or skew of the CR encoder e of the CR encoder sensorFailure of the CR motor e of the main boardOperation failure of the CR motor, stopped by

was stopped by;•Obstacles such as jammed paper•Interfere with the ink system•Disengaging or breakage of the gearsFailed to read the CR g of the CR timing ination of the CR encoder or skew of the CR encoder e of the CR encoder e of the main boardThe CR motor did not run, or the CR could not move

ad of the CRFailed to read the CR timing belt become frayed or ination of the CR encoder nection, break, skew or damage of the CR

encoder e of the CR encoder e of the CR motor (the lead wire is broken

or the connector is disconnected)e of the main board000021CR PID excess

load error---000022CR PID excess

speed errorMain boardCN702CN608000023CR PID

reverse errorMain boardCN702CN608000024CR PID lock

errorMain boardCN702CN608000025CR PID speed

fall errorOperation failure of the CR was stopped by;•Obstacles such as jammed paper•Overload of the mechanism•Interfere with the ink systemFailed to read the CR motor timing belt become loosened or ination of the CR encoder or skew of the CR encoder e of the CR motor

e of the main boardMain boardCN702CN608TroubleshootingFatal Error Code List17ConfidentialEPSON WF-3720 SeriesError

codeError nameCR load

position

driving time

errorRevision CPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main that no obstacle exist in the CR

motion range.

the CR lock and ink system for any

the timing belt for fraying or

the load applied to the CR by

moving it by if the lubricant on the CR shaft is

the CR drive the CR encoder scale if it is

e the CR motor with a new e the main board with a new the CR encoder scale if it is

the FFC of the CR e the CR encoder sensor with a new

e the main board with a new that no obstacle exist in the CR

motion range.

the CR lock and ink system for any

the timing belt for fraying or

the CR encoder scale if it is

the CR encoder FFC or the

e the CR encoder sensor with a new

e the main board with a new tor

No.000030Malfunction or crash of the firmware---000031CR load

position excess

load errorThe CR motor stopped running in the middle of the

CR was stopped by;•Obstacles such as jammed paper•Overload of the mechanism•Interfere with the ink system•Disengaging or breakage of the gears•Disengaging, fraying, jumping of the timing

beltFailed to read the CR ination of the CR encoder e of the CR motor (not completely broken)e of the main boardMain boardCN702CN608000032CR load

position excess

speed errorFailed to read the CR ination of the CR encoder or skew of the CR encoder e of the CR encoder sensorFailure of the CR motor e of the main boardOperation failure of the CR motor, stopped by

was stopped by;•Obstacles such as jammed paper•Overload of the mechanism•Interfere with the ink systemFailed to read the CR g of the CR timing ination of the CR encoder or skew of the CR encoder e of the CR encoder e of the main boardMain boardCN702CN608000033CR load

position

reverse errorMain boardCN702CN6081.3.2.3Printer (PF)Error

codeError namePossible causeMalfunction or crash of the firmwareThe PE sensor remains in paper detection status and a

paper jam error occurs instead of causing a fatal

error.The PF motor stopped running in the middle of the

PF was stopped by;•Obstacles such as jammed paper•Overload of the paper feed mechanism•Disengaging or breakage of the gearsFailed to read the PF motor timing belt become frayed or ination of the PF encoder nection, break, skew or damage of the PF

motor cable/encoder e of the PF motor (not completely broken)e of the main boardConfirmation the printer off and back it the error still occurs after the restart,

replace the main that no pieces of paper or foreign

objects exist in the paper the load of the paper feed

the wheel train of the PF drive and

the timing belt for fraying or the PF encoder scale for damage or

the PF encoder FFC or the

e the PF motor with a new e the main board with a new tor

No.000040PF PID driving

time error---000041PF PID excess

load error---TroubleshootingFatal Error Code List18ConfidentialEPSON WF-3720 SeriesError

codeError namePossible causeFailed to read the PF motor ination of the PF encoder or damage of the PF encoder e of the PF encoder sensorFailure of the PF motor e of the main boardPaper feed fails, stopped by feed was stopped by;•Obstacles such as jammed paper•Overload of the paper feed mechanism•Disengaging or tooth breakage of wheel train

of the paper feed mechanismFailed to read the PF motor g of the PF timing ination of the PF encoder or damage of the PF encoder e of the PF encoder e of the main boardThe PF motor did not run or obstacles exist in the

paper ad of the paper feed PF timing belt become frayed, jumping, or

the wheel train of paper feed mechanism is

disengaged or its tooth is brokenFailed to read the PF motor ination of the PF encoder nection, break, skew or damage of the PF

encoder e of the PF encoder e of the PF motor (the lead wire is broken

or the connector is disconnected)e of the main boardRevision CConfirmation the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new

e the main board with a new that no pieces of paper or foreign

objects exist in the paper the load of the paper feed

the wheel train of the PF drive and

the timing the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new

e the main board with a new that no jammed paper exist in the

paper the load of the the wheel train of the PF drive and

the timing belt for fraying or the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new

the connector of the PF e the PF motor with a new e the main board with a new the printer off and back it the error still occurs after the restart,

replace the main that no pieces of paper or foreign

objects exist in the paper the load of the paper feed

the wheel train of the PF drive and

the timing belt for fraying or the PF encoder scale if it is

e the PF motor with a new e the main board with a new the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new e the main board with a new tor

No.000042PF PID excess

speed errorRelay boardCN703CN502000043PF PID reverse

errorRelay boardCN703CN502000044PF PID lock

errorRelay boardCN703CN502000050PF load

position

driving time

errorMalfunction or crash of the firmware---000051PF load

position excess

load errorThe PF motor stopped running in the middle of the

PF was stopped by;•Obstacles such as jammed paper•Overload of the paper feed mechanism•Disengaging or breakage of the gearsFailed to read the PF motor g of the timing ination of the PF encoder e of the PF motor (not completely broken)e of the main boardFailed to read the PF motor ination of the PF encoder or damage of the PF encoder e of the PF encoder sensorFailure of the PF motor e of the main board---000052PF load

position excess

speed errorRelay boardCN703CN502TroubleshootingFatal Error Code List19ConfidentialEPSON WF-3720 SeriesError

codeError namePossible causePaper feed fails, stopped by feed was stopped by;•Obstacles such as jammed paper•Overload of the paper feed mechanism•Disengaging or tooth breakage of wheel train

of the paper feed mechanismFailed to read the PF motor g of the PF timing ination of the PF encoder or damage of the PF encoder e of the PF encoder e of the main boardRevision CConfirmation that no pieces of paper or foreign

objects exist in the paper the load of the paper feed

the wheel train of the PF drive and

the timing belt for fraying or the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new e the main board with a new tor

No.000053PF load

position

reverse errorRelay boardCN703CN5021.3.2.4Printer (I/S)Error

code000100Error nameIS PID driving

time errorPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for disengage or the I/S encoder scale if it is

e the ink system with a new e the main board with a new the I/S encoder scale if it is

the I/S encoder FFC or the

e the ink system with a new e the main board with a new the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for tooth breakage or the I/S encoder scale if it is

the cable/FFC of the I/S motor/e the ink system with a new e the main board with a new the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for tooth breakage or the I/S encoder scale if it is

the cable/FFC of the I/S motor/e the ink system with a new e the main board with a new tor

No.---Malfunction or crash of the firmwareThe I/S motor stopped running in the middle of the

ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gearsFailed to read the I/S ination of the I/S encoder e of the I/S motor (not completely broken)e of the main boardFailed to read the I/S motor ination of the I/S encoder or skew of the I/S encoder e of the I/S encoder sensorFailure of the I/S motor e of the main boardOperation failure of the I/S motor, stopped by

ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gearsFailed to read the I/S ination of the I/S encoder or skew of the I/S motor cable/encoder

e of the I/S encoder e of the main boardThe I/S motor did not ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gearsFailed to read the I/S ination of the I/S encoder , skew or damage of the I/S motor cable/encoder e of the I/S encoder e of the I/S motor (the lead wire is broken

or the connector is disconnected)e of the main board000101IS PID excess

load error---000102IS PID excess

speed errorMain boardCN701CN508000103IS PID reverse

errorMain boardCN701CN508000104IS PID lock

errorMain boardCN701CN508TroubleshootingFatal Error Code List20ConfidentialEPSON WF-3720 SeriesError

codeError nameIS load

position

driving time

errorRevision CPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for disengage or the I/S encoder scale if it is

e the ink system with a new e the main board with a new the I/S encoder scale if it is

the I/S encoder FFC or the

e the ink system with a new e the main board with a new the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for tooth breakage or the I/S encoder scale if it is

the cable/FFC of I/S motor/e the ink system with a new e the main board with a new tor

No.000110Malfunction or crash of the firmware---000111IS load

position excess

load errorThe I/S motor stopped running in the middle of the

ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gearsFailed to read the I/S ination of the I/S encoder e of the I/S motor (not completely broken)e of the main boardFailed to read the I/S ination of the I/S encoder or skew of the I/S encoder e of the I/S encoder sensorFailure of the I/S motor e of the main boardOperation failure of the I/S motor, stopped by

ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gears Failed to read the I/S ination of the I/S motor encoder or skew of the I/S motor cable/encoder

e of the I/S encoder e of the main boardMain boardCN701CN508000112IS load

position excess

speed errorMain boardCN701CN508000113IS load

position

reverse errorMain boardCN701CN5081.3.2.5Printer (Head/CSIC)Error

codeError namePossible causeDisconnection, break, skew or damage of the head

FFCOverheat of the e of the e of the main boardOccurs in-between print passes (after printing

one pass and before printing the next pass)Disconnection, break, skew or damage of the head

FFCOverheat of the e of the e of the main boardOccurs every after ink flushing operation(Flushing before starting printing, flushing

after manual cleaning and etc.)Failure of the main boardOccurs after receiving a print job and starting

printingDisconnection, break, skew or damage of the head

FFCOccurs after receiving a print job and starting

printingFailure of the thermistor inside the printheadTemperature around the printhead is out of the

range from -20 to 80 degrees mation the head FFC for disconnection,

break, skew or e the printhead with a new e the main board with a new tor

No.031001HeadHot

detect error

(pre printing)Main boardCN606CN607CN608031002HeadHot

detect error

(after flushing) the head FFC for disconnection,

break, skew or e the printhead with a new e the main board with a new boardCN607031003Transistor

temperature

errorReplace the main board with a new the head FFC for disconnection,

break, skew or e the printhead with a new e the main board with a new one.---031004Head

temperature

errorMain boardCN607TroubleshootingFatal Error Code List21ConfidentialEPSON WF-3720 SeriesError

codeError namePossible causeFailure of the power source for the e of the circuitDisconnection, break, skew, or damage of the

head t of fuse on the main boardFailure of the printheadOccurs at power-on, when replacing the ink

cartridge, in-between print passes, and after

flushing FFC failure (skew, foreign object attached)e of the e of the main board(Occurrence frequency based on past record is 1. > 2.

> 3.) FFC failure (skew, foreign object attached)e of the e of the main boardFailure of the main boardOccurs at power-on, and during operation for

replacing the ink cartridgeError in the printer settingsFailure of the main boardOccurs at power-onRevision CConfirmation the fuse has not blown out1)Check the head FFC for disconnection,

break, skew or the fuse has blown out1)Replace the main board with a new the other cases1)Replace the printhead with a new tor

No.031006Blowout of a

fuse error

(Head)Main boardCN606031008VBS

overvoltage

the head e the printhead with a new e the main board with a new boardCN606031011HCS the head e the printhead with a new e the main board with a new the CRCM FFC for disconnection,

break, skew or the error still occurs after the restart,

replace the main the printer off and back it the error still occurs after the restart,

replace the main boardCN606033001Blowout of a

fuse error

(CRCM)Other Ink

device errorOther Ink

device errorOther Ink

device errorCRCM access

error

(Hard factor)CRCM access

error

(Hard factor)Main boardCN604033005-----033006Disconnection, break, skew or damage of the CRCM

FFCFailure of the CSIC terminal/CR contact moduleFailure of the main the CRCM FFC for disconnection,

break, skew or the error still occurs after the restart,

replace the main boardCN610CSIC access

error

(Hard factor)Disconnection, break, skew or damage of the CRCM

FFCFailure of the CSIC terminal/CR contact moduleFailure of the main board (mismatch of the printer

settings that cannot be changed when repairing the

printer)Occurs at the CRCM FFC for disconnection,

break, skew or the error still occurs after the restart,

replace the main boardCN6081.3.2.6Printer (Others)Error

code033501Error nameILS

environmental

errorILS continuous

reflected light

errorILS no

reflected light

errorILS shift

length errorILS Empty Jig

errorPossible causeConfirmation the sensor is directly exposed to light,

block out the light.

e the PIS sensor with a new e the jig I/e the PIS sensor with a new e the PIS sensor FFC with a new

e the PIS sensor with a new e the I/C with a new e the jig I/e the PIS sensor with a new e the jig I/e the PIS sensor with a new tor

No.---The PIS sensor received unexpected amount of lightThe PIS sensor received unexpected amount of

reflected light from the jig I/CAnti-reflection film of the I/C has been removedElectric voltage for the PIS sensor is insufficient•Break of the FFC•The PIS sensor has deteriorated•Reflected light from the I/C is insufficient At power-on, during replacing I/CPositioning of the I/C and the PIS sensor is from Empty jig I/C is insufficient033502---033503

Main boardCN505------TroubleshootingFatal Error Code List22ConfidentialEPSON WF-3720 SeriesError

code033506Revision CPossible causeLight from Full jig I/C is too muchElectric voltage for the PIS sensor is insufficient•Break of the FFC•The PIS sensor has deteriorated•Reflected light from the I/C is insufficientAt power-on, during replacing I/C, during

switching APGThis error code is not displayed but the error history is

saved.The carriage does not ad of the carriage drive mechanism (paper

jam, foreign object)e of the ink e of the CR e of the main boardError nameExcessive

Light errorConfirmation e the jig I/e the PIS sensor with a new e the I/C with a new e the PIS sensor with a new tor

No.---033507Insufficient

Light errorMain boardCN506034001Home position

that no obstacle exist in the

carriage motion ly unlock the carriage. (If

unlocking is impossible, the problem

caused by failure of the ink system.)

the load applied to the CR by

moving it by the printer on and check if the carriage

moves. If it still does not move, the motor is

broken or failure of the main board.---034500Ink cartridge

replacement

timing contact

detection errorDriver

mismatch errorBecause the I/C is not securely installed, it comes in

contact with the housing.Non-supported printer driverMismatch between custom printer driver and custom

l the I/C securely.---060002Check the OS and the version of the printer

driver.---1.3.2.7System ErrorError

code2026202xxxxxError nameWi-Fi Board

failureFirmware bugPossible causeFailure or disconnection of the wireless network boardAn error code will be assigned to each firmware internal

error as mation procedure•Check the wireless network board.•Check the FFC.•Firmware version•Main boardConnector

boardCN301---TroubleshootingFatal Error Code List23ConfidentialEPSON WF-3720 SeriesRevision C1.4 Service Support ModeOverviewService support mode is a service dedicated special mode that can be started by a special operation, and allows

you to execute functions including adjustment, inspection, and individual operation check SW

SW1Touch Panel Left [LEFT]Touch Panel Right [RIGHT]Touch Panel Center [CENTER]Figure operation on Service Support ModeService Support Mode startup and operating the [SW1] and [Power SW] button until the screen switches, starting the pressing the Touch Panel, ensure that an object at least 20 mm(L) × 25 mm(W) × 2

mm(H) in size is used. (E.g. Press with a finger diagonally)Power SW

SW1Figure e Support Mode startup and operating proceduresTroubleshootingService Support Mode24ConfidentialEPSON WF-3720 e the Touch Panel, and enter the to enter: 49515Operating the Touch Panel right [RIGHT] until the value you wish to input is on the Touch Panel left [LEFT] to check the value. The value will change to “*”, and await entry of

the next steps 1 and 2 to enter the 5 digit entry is completed, tap the Touch Panel center [CENTER] to :[Right]SHIFT:[Left]/FIN:[Center] **5Touch Panel Left [LEFT]Touch Panel Right [RIGHT]Touch Panel Center [CENTER]Figure e Support Mode operating procedureIt is not possible to return to the previous digit after shifting digits. If you wish to correct

the number of the previous digit, proceed with the steps until after step 5 and then

perform input again.Please note that the execute button is not enabled until at least two digits have been

on if enter and execute the wrong IDWhen a different mode starts:If you enter the wrong ID and a different mode starts, there is the possibility of changing

important settings of the unit, so press the power button to turn off the power

immediately and then perform the process again to enter the correct ID number.When non-existent ID number:The following panel LCD display appears and the power is turned off ID is not found!!Please TroubleshootingService Support Mode25ConfidentialEPSON WF-3720 SeriesService Support Mode menu configurationMaintenance SP Mode　Run:Center / Select:r Inspection Sheet Print Log Get Lock CheckRevision CFigure e Support Mode: Top Menu ScreenItemPrinter modeDisplayPrinter Inspection ModeOverviewUsage situationWith the ADF/SCN Unit removed, you

Repair workingcan carry out adjustment addition to checking confirming

normal status sheet information, you

Troubleshootingcan also check information required for

performing analysis, copy the user

log data to external storage media such as

Troubleshootinga USB memory device connected to the

main replacing after return, or

Repair workingcompleting repairs, you can check if the

TroubleshootingCR lock is e status sheet printStatus Sheet Print ModeUser log data get modeUser Log Get ModeCR lock checkCR Lock CheckTroubleshootingService Support Mode26ConfidentialEPSON WF-3720 SeriesRevision C1.4.1 Status Sheet InformationThe following status sheets can be printed from the section explains about each item printed on the status sheets.Overview of Status SheetsPrinter Information SheetSupply Status Sheet

Usage History SheetService Status SheetStatus Sheet ItemsPrinter information sheet (total pages: 6 sheets)ItemDevice IDSerial NumberMAC AddressMemory CapacityHardware

ConfigurationCard Reader StatusFirmwareMain FirmwareNetwork FirmwareQPITExplanationDevice ID (product name) is serial number of the product is address of the product is ty of the memory inside the product is

tion condition of a device for user

authentication is n of the firmware is n of the main firmware is n of the NW firmware is n of the QPIT is current language setting is setting of mute (on/off) is displayed.: printer settings information: supported model numbers of consumables or periodic replacement parts, and the total number of sheets fed into the printer.: usage history such as the total number of printed pages per function.: in addition to the information included in the above three sheets,

information required for servicing is also provided.Basic settingsLanguageMuteButton PressError NoticeReceive Completion

NoticeSend Completion NoticePrint Completion NoticeRing ToneReceiverSound Type

settings>NormalSound level setting (0 to 10) is timer settingPower Off TimerUSB I/F Timeout SettingPrinting LanguageAuto Error SolverMemory DeviceMemory Device

InterfaceFile SharingUSBNetworkWhether the sleep timer is enabled or not is

displayed. When enabled, the time period before the

product enters sleep mode is also Power Off Timer setting is I/F time out settings are language settings are r the auto error resolver options are enabled

or not is r the external memory setting is enabled or

not is file sharing setting (which connection way of

computers, USB or network, is allowed to access the

external memory) is displayed.

The Ink Drying Time when duplex printing is

r the setting is enabled or not is r the setting is enabled or not is Drying TimePC connection via USBNFCTroubleshootingService Support Mode27ConfidentialEPSON WF-3720 SeriesItemPaper cassette 1 to

Paper cassette 4MP trayPaper SizePaper TypePaper Size Auto DetectPaper SizePaper TypeExplanationRevision CPaper cassettePaper size and type settings of each of the cassettes

and whether the auto paper size detection feature is

enabled or not are r the auto switching function is enabled or

not is displayed.A4/Letter Auto SwitchingPaper

source

settingsAuto

Selection-CopyAuto

Selection-FaxAuto

Selection-OtherAuto Selection-CopyAuto Selection-FaxAuto Selection-OtherRear Paper Feed PriorityPaper Size NoticePaper Type NoticeTop OffsetLeft OffsetTop Offset in BackLeft Offset in BackCheck Paper WidthSkip Blank PagePaper SizePaper TypeOrientationQualityInk Save ModePrint OrderNumber of CopiesBinding MarginAuto Paper Ejection2-Sided PrintingFont SourceFont NumberPitchHeightSymbol SetFormCR FunctionLF FunctionPaper Source AssignError SheetColorationBinaryPDF Page SizePCLPSPDFPaper cassette 1 to paper

cassette 2, MP trayPaper cassette 1 to paper

cassette 2, MP trayPaper cassette 1 to paper

cassette 2, MP trayWhether the auto paper source selection setting for

each of the functions is enabled or not is r the setting is enabled or not is r the setting is enabled or not is r the setting is enabled or not is settingsUniversal Print

SettingsThe offset setting (-30 to 30) is r the setting is enabled or not is r the setting is enabled or not is size setting is type setting is orientation setting (portrait or landscape) is

print quality setting (Draft, Standard, or Best) is

displayed.

Whether the setting is enabled or not is print order setting (print from the first page or

last page) is rd number of copies (1 to 999) is Binding Margin is r the setting is enabled or not is r the setting is enabled or not is Print

ConfigurationThe Setting of PCL Menu is displayed.Whether the setting is enabled or not is color setting (Color or Mono) is r the setting is enabled or not is PDF paper size setting is version of each of the printer language is

displayed.TroubleshootingService Support Mode28ConfidentialEPSON WF-3720 SeriesItemSubject (“Scan to Email” only)ColorFile FormatDocument Open Password (not provided for “Scan

to Cloud”)Permissions password (not provided for “Scan to

Cloud”)PrintingEditingResolution (not provided for “Scan to Cloud”)2-SidedBinding Position

Email>

Network

Folder/FTP>

Memory

Device>

Cloud>Scan areaRemove shadowSurroundCenterRemove Punch HolesErasing PositionRevision CExplanationThe subject of email is color setting (Color or Mono) is format setting is r the password setting is enabled or not is

r the password setting is enabled or not is

r printing scanned document is permitted or

not is r editing scanned document is permitted or

not is resolution setting is r the 2-sided scanning is enabled or not is

g position of documents (left/top/--- (in case

of one-side scanning)) is al document size setting is r the setting is enabled or not is frame width setting (0 to 40 mm/---(in case of

the shadow remove setting is disabled)) is center width setting (0 to 40 mm/---(in case of

the shadow remove setting is disabled)) is r the setting is enabled or not is erasing setting (left edge/right edge/top edge/bottom edge/--- (in case of the remove punch holes

setting is disabled)) is erasing amount (0 to 20 mm/--- (in case of the

remove punch holes setting is disabled)) is

document orientation setting (portrait or

landscape) is quality setting (Text/Text & Image/Photo) is

displayed.

The density setting (-4 to 4) is name prefix setting for scanned file is r the setting is enabled or not is r the setting is enabled or not is Compression Ratio is maximum file size that can be attached to an

email is r the setting is enabled or not is r the setting is enabled or not is version is product key is displayed (“---” is displayed

when it is not set).Scan

settingsErase AmountOrientation (Original)Document TypeDensityFilename Prefix (not provided for “Scan to

Cloud”)DateTime of DayCompression Ratio (not provided for “Scan to

Cloud”)Attached File Max Size (“Scan to Email” only)Admin SettingsEpson Open Platform

InformationLock SettingAccess ControlVersionProduct keyTroubleshootingService Support Mode29ConfidentialEPSON WF-3720 SeriesSupply Status Sheet (total pages: 2 sheets)ItemDevice IDSerial NumberMAC AddressMemory CapacityHardware ConfigurationCard Reader StatusFirmwareMain FirmwareNetwork FirmwareQPITBlackCyanMagentaYellowMaintenance BoxPeriodic

Replacement

Parts

InformationOptional Cassette Informationmaintenance roller 1

to

maintenance roller 2Rear Paper FeedCassette 2Part NumberSerial NumberPart NumberSerial NumberPart NumberSerial NumberPart NumberSerial NumberPart NumberPart NumberNumber of Sheets LoadedNumber of Sheets LoadedFirmware VersionExplanationRevision CDevice ID (product name) is serial number of the product is

address of the product is ty of the memory inside the product

is tion condition of a device for user

authentication is n of the firmware is n of the main firmware is n of the NW firmware is n of the QPIT is Supply

UnitSupply

StatusModel number of each of the ink

cartridges is cturer's serial number of each of

the ink cartridges is model number of the Maintenance

Box is t value of the counter for the

periodic replacement part, the number of

replacements of the part, and the model

number of the part are version of the firmware of cassette 2 is

eshootingService Support Mode30ConfidentialEPSON WF-3720 SeriesUsage History Sheet (total pages: 2 sheets)ItemDevice IDSerial NumberMAC AddressHardware

ConfigurationMemory CapacityCard Reader StatusFirmwareMain FirmwareNetwork FirmwareQPITUsage HistoryFirst Time PrintingTotal Number of PagesTotal Number of B&W PagesTotal Number of Color PagesTotal Number of 2-Sided Printing PagesTotal Number of 1-Sided Printing PagesA3/LedgerA4/Letter

Size>(1-sided/2-sided,

B&W/Color)A5A6B4/LegalB5EnvelopeOthersB&W CopyColor CopyB&W FaxColor FaxB&W ScanNumber of printsColor ScanB&W Print from Computer or Mobile DeviceColor Print from Computer or Mobile DeviceB&W Print from Memory Device or

Other FunctionsColor Print from Memory Device or

Other FunctionsESC/P-R

Language>PCLPS and PDFOthersExplanationRevision CDevice ID (product name) is serial number of the product is

address of the product is ty of the memory inside the product

is tion condition of a device for user

authentication is n of the firmware is n of the main firmware is n of the NW firmware is n of the QPIT is date and time when the printer printed

for the first time is total number of printed pages is

total number of pages printed in

monochrome is total number of pages printed in color

is total number of printed 2-sided pages

is total number of printed one-sided

pages is of PagesThe total number of printed pages per

paper size is ed count per function (one-sided/2-sided, monochrome/color) is also

displayed for each paper total number of printed pages for each

of the purposes is version of each of the printer language

is eshootingService Support Mode31ConfidentialEPSON WF-3720 SeriesService Status Sheet (total pages: 16 sheets)ItemDevice IDSerial NumberMAC AddressMemory CapacityHardware ConfigurationCard Reader StatusFirmwareMain FirmwareNetwork FirmwareQPITSleep Timer

ExplanationRevision CDevice ID (product name) is serial number of the product is

address of the product is ty of the memory inside the

product is tion condition of a device for user

authentication is n of the firmware is n of the main firmware is

n of the NW firmware is n of the QPIT is r the sleep timer is enabled or not

is displayed. When enabled, the time

period before the product enters sleep

mode is also r the auto power off setting is

enabled or not is displayed. When

enabled, the time period before the printer

automatically turns off is also Ink Drying Time when duplex

printing is SettingsPower Off SettingsInk Drying TimeCassette 1

to Cassette

4MP trayPaper SizePaper TypePaper Size Auto DetectPaper SizePaper TypeTop Offset

Left Offset

Print SettingsUniversal

Print

SettingsTop Offset in BackLeft Offset in BackCheck Paper WidthSkip Blank PageIP AddressSubnet MaskDefault GatewayPrimary DNS ServerNetwork SettingsSecondary DNS ServerDNS Domain NameProxy Server SettingsProxy ServerProxy Server Port NumberPaper

Source

SettingsPaper CassettePaper size and type settings for each of the

paper sources are offset setting (-30 to 30) is r the setting is enabled or not is

r the setting is enabled or not is

network settings are eshootingService Support Mode32ConfidentialEPSON WF-3720 SeriesItemSubject (“Scan to Email” only)Color ModeFile Format (not provided for “Scan to Cloud”)Document Open Password (not provided for “Scan

to Cloud”)Permissions Password (not provided for “Scan to

Cloud”)PrintingEditingResolution (not provided for “Scan to Cloud”)2-SidedBinding PositionScan Area (not provided for “Scan to Cloud”)Remove Shadow (not provided for “Scan to Cloud”)SurroundScan

settings

Folder/FTP>

Device>ExplanationThe subject of email is on CThe color setting (Color or Mono) is

format setting is r the password setting is enabled

or not is r the password setting is enabled

or not is r printing scanned document is

permitted or not is r editing scanned document is

permitted or not is resolution setting is r the 2-sided scanning is enabled

or not is g position of documents (left/top/--- (in

case of one-side scanning)) is al document size setting is r the setting is enabled or not is

frame width setting (0 to 40 mm/---(in case of the shadow remove setting is

disabled)) is center width setting (0 to 40 mm/---(in case of the shadow remove setting is

disabled)) is r the setting is enabled or not is erasing setting (left edge/right edge/top edge/bottom edge/--- (in case of the

remove punch holes setting is disabled)) is

erasing amount (0 to 20 mm/--- (in

case of the remove punch holes setting is

disabled)) is document orientation setting (portrait

or landscape) is quality setting (Text/Text & Image/Photo) is setting of Mixed Size Original is density setting (-4 to 4) is displayed.------Whether the setting is enabled or not is r the setting is enabled or not is displayed.---The data compression ratio setting (Low/Middle/High) is maximum file size that can be

attached to an email is product key is displayed (“---” is

displayed when it is not set).CenterRemove Punch HolesErasing SettingErase AmountOrientation (original)Document TypeMixed Size OriginalDensityRemove BackgroundFile Name Prefix (not provided for “Scan to Cloud”)DateTimeContinuous Scan (ADF)Compression Ratio (not provided for “Scan to

Cloud”)Attached file Max Size (“Scan to Email” only)Epson Open Platform

InformationProduct keyTroubleshootingService Support Mode33ConfidentialEPSON WF-3720 SeriesItemFax FunctionLarge-Capacity

Paper Feed

UnitIntermediate UnitOptional

Cassette 1Optional

Cassette 2Optional

Cassette 3Serial NumberFW versionSerial NumberFW versionSerial NumberFW versionSerial NumberFW versionSerial NumberFW versionPart numberSerial NumberPart numberSerial NumberPart numberSerial NumberPart numberSerial NumberPart numberPart numbermaintenance roller 1 tomaintenance roller 4Number of Sheets LoadedNumber of ReplacementsNumber of Sheets LoadedNumber of ReplacementsNumber of Sheets LoadedNumber of ReplacementsPart numberNumber of Sheets LoadedBelt unitNumber of ReplacementsPart numberNumber of Sheets LoadedBelt cleanerNumber of ReplacementsPart numberADF feed

rollerHigh

capacity

input unitNumber of Sheets LoadedNumber of ReplacementsPart numberNumber of Sheets LoadedNumber of ReplacementsPart numberID of the print head is displayed.------ExplanationRevision CWhether the fax feature is enabled or not

is SettingsFirmware version of each of the option

cassettes are er FunctionBlackCyanInk CartridgesMagentaYellowMaintenance BoxModel number and manufacturer's serial

number of each of the ink cartridges is

model number of the Maintenance

Box is number of each of the feed rollers

is number of sheets fed by each of the

maintenance rollers is number of replacements (the number

of times the counter is reset) of each of the

paper feed rollers is

StatusRear Paper

FeedMist / VOC

Filter

Periodic replacement

partsPrint head serial IDHind head sensor degration

TroubleshootingService Support Mode34ConfidentialEPSON WF-3720 SeriesItemFirst Time PrintingTotal Number of Pages

Function>Total Number of B&W PagesTotal Number of Color PagesA3/Ledger

Paper Size>(1-sided/2-sided,

B&W/Color)A4/LetterA5A6B4/LegalB5EnvelopeOtherB&W Print from Computer or

Mobile DeviceColor Print from Computer or

Mobile DeviceB&W Copy

Usage>Color CopyB&W FaxColor FaxB&W Print from Memory Device or

Other FunctionsUsage HistoryColor Print from Memory Device or

Other FunctionsPlain papersLetterheadRecycledColorPreprintedHigh quality plain paper

Type>Thick-Paper 1Thick-Paper 2Thick-Paper 3MatteUltra GlossyPrem. GlossyPrem. semiglossGlossyEnvelopeOtherNumber of

Sheets

ScannedNumber of

Sheets

LoadedThe Cumulative number of paper

jamDocument Table (Number of pages)ADF (Number of pages)ADF (Number of Fed Sheets)Cassette 1 to Cassette 4, Rear Paper

Feed, Paper Feed SlotExplanationRevision CThe data and time the printer printed for

the first time are total number of pages printed by the

printer is total number of pages printed in

monochrome is total number of pages printed in color

is total number of printed pages per

paper size is displayed. Detailed count per

function (one-sided/2-sided,

monochrome/color) is also displayed for

each paper total number of printed pages for each

of the purposes is total number of pages printed on each

of the paper types is : Count in number of sheet.

Including paper number does not

meet with the other total number of times a paper jam

error occurs is total number of pages scanned on the

scanner glass or in the ADF is displayed.

The total number of document sheets fed

by the ADF is total number of printed pages per

paper source is eshootingService Support Mode35ConfidentialEPSON WF-3720 SeriesItemUser

Adjustment

Cleaning

HistoryNozzles

Clogging

StateCodeNameTimer of dayCodeTypeTimer of dayRankPrinter ErrorPaper Jam ErrorSetting Change HistoryFatal Error When PrintingExplanationRevision CAdjustment name and execution date and

time of last five adjustments executed by

the user are ng type and execution date and time

of last five cleaning operations are

displayed.A number that represents the level of

nozzle clogging is each of the errors, the following

information is displayed- Error Code- Sub Code- Date of Occurrence- Number of Pages- Internal Temperature- Internal Humidity- Paper PathFor each of the errors, the following

information is displayed- Error Code- Date of Occurrence- Number of Scan PagesFor each of the errors, the following

information is displayed- Error Code- Date of OccurrenceInk coverage of print jobs finished before

printing this status sheet is displayed

according to the rule below.L: less than 5%, M: 5% to 20%, H: more

than 20%Ink coverage of the last print job is

displayed according to the rule below.L: less than 20%, M: 5% to 50%, H: more

than 50%Error

HistoryScanner ErrorFatal Error When ScanningFax ErrorNetwork ErrorSystem ErrorOther ErrorPD1 LevelCoverageCoverage

RatioPD2 LevelPrinter ErrorScanner ErrorStatusFax ErrorNetwork ErrorOther Error---TroubleshootingService Support Mode36ConfidentialCHAPTER2DISASSEMBLY/REASSEMBLYConfidentialEPSON WF-3720 SeriesRevision C2.1 OverviewThis chapter describes procedures for disassembling the main parts/units of WF-3720 Series. Unless otherwise

specified, disassembled parts/units can be reassembled by reversing the disassembly procedure. See the cautions

or tips for disassembly/reassembly described in "2.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit (p54)".Read the " Safety Precautions (p3)" before disassembling and you have to remove units or parts that are not described in this chapter, see the exploded diagrams of SPI

(Service Parts Information).2.1.1 ToolsUse only specified tools to avoid damaging the (+) Phillips screwdriver #1(+) Phillips screwdriver #2Flathead screwdriverFlathead Precision screwdriver #1TweezersLongnose pliersAcetate TapeNote1:Some of the tools listed above are commercially available.2:EPSON provides the tools listed with EPSON part bilityOOOOOO---EPSON Part Code1080530---------------10039632.1.2 JigsNameThickness gauge (1.6 mm)Thickness gauge (1.24 mm)Teflon tape (thickness: 0.08 mm)Q’ty111EPSON Part CodeCommercially availableCommercially availableCommercially availableDisassembly/ReassemblyOverview38ConfidentialEPSON WF-3720 SeriesRevision C2.1.3 Locations of the Parts/UnitsThis section shows the locations of the main parts/units of WF-3720 parts/units which can not be seen in the following pictures are indicated in dotted lines

().Exterior partsFrontRight165243LeftRear798No.12345 Panel Assy (p49) Paper Cassette (p50) Stacker Assy (p53) NFC Board (p49)Name ADF Document Support (p50)No.6789 ADF Unit (p50) SCN Unit (p50) Duplex Unit (p50) Ink Eject Assy (p49)NameFigure or PartsDisassembly/ReassemblyOverview39ConfidentialEPSON WF-3720 SeriesPrinter mechanismRevision C615243No.123 Main Frame Assy (p52) Holder CSIC Assy (p49) PIS Board (p51)NameNo.456Name Paper Guide Front Assy (p52) Paper Guide Upper Assy. (p51) PE Sensor (p53)Figure r Mechanism: Front54132No.123 CR Unit (p52) Ink System Assy (p53) Printhead (p49)NameNo.45Name Holder Star Wheel Assy. (p51) Front Frame (p51)Figure r Mechanism: RightDisassembly/ReassemblyOverview40ConfidentialEPSON WF-3720 SeriesRevision C615432No.123 WiFi Board (p51) Speaker (p53) PF Scale (p52)NameNo.456 PF Encoder Sensor (p51) FAX Assy (p53) Main Board (p51)NameFigure r Mechanism: Left312No.13 Head FFC (p51) Holder Cam Assy (p52)NameNo.2 CR Motor (p51)NameFigure r Mechanism: RearDisassembly/ReassemblyOverview41ConfidentialEPSON WF-3720 SeriesRevision C2.1.4 Standard Operation Time for servicing the productThe following are the standard operation time for servicing the product. Those are based on the MTTR result

measured using a prototype of WF-3720 Series. Perform servicing referring to this operation standard underlined parts/units are supplied as After Service rd Operation TimeTime (mm:ss)Parts/UnitReplacement2:470:511:092:202:201:012:240:240:180:140:340:470:203:474:050:240:470:200:531:280:390:551:430:553:373:394:154:156:353:423:535:293:536:515:436:513:063:47Adjustment/inspection------------------21:27---------------------------------------------------------0:420:42---1:460:03---------------------Total2:470:511:092:202:201:0125:510:240:180:140:340:470:203:474:050:240:470:200:531:280:390:551:430:553:373:394:574:576:355:283:565:293:536:515:436:513:063:47Housing UpperHolder Board Assy CRCM Assy CSIC Connector (x4) Holder CSICCover Cable Head InnerPrintheadGuide I/CPickup Roller AssyHolder PickupPickup RollerPaper Stopper AssyCover-IFCover-ink-EjectInk Eject AssyStacker Support Front AssyCover ADF AssyADF Document SupportFrame Upper ADF Assy ADF PAD Assy. & SpringDocument PadCover Front ADFFrame Front ADF AssyCover Rear ADFADF MechADF/SCN Unit ADF Unit SCN UnitGround Plate PSPower Supply Assy. Housing Panel Lower Holder Tilt Left Panel Board NFC Board Housing Panel UpperFrame RightSCN Hinge AssyDisassembly/ReassemblyOverview42ConfidentialEPSON WF-3720 SeriesTable rd Operation TimeTime (mm:ss)Parts/UnitReplacement3:543:545:247:238:1111:1413:4014:0814:0816:0216:1616:3516:4217:0117:5819:0617:197:328:089:178:148:499:319:5010:2510:3610:368:317:549:029:028:287:588:188:439:047:357:237:3613:3210:5610:19Revision CAdjustment/inspection---------19:19---------21:01---18:25---------------------------0:23---5:203:58------------------0:430:25------------------------0:22---0:13Total3:543:545:2429:258:1111:1413:4037:5214:0837:1016:1616:3516:4217:0117:5819:0617:197:328:0812:238:1416:5216:129:5010:2510:3610:368:317:5412:2812:108:287:588:188:439:047:357:237:3613:5410:5610:32 Rack Hinge Box Gear Hinge Cassette SensorPrinter Mechanism CR Scale Main Board Assy. Shield Plate Upper Main Board Frame Left Main Frame Assy Cap Detector PW PW Sensor Main Frame Timing Belt CR Encoder CR Unit Paper Guide Front Assy WiFi Board Holder Driven Assy (w/Spring) CR Motor Ground Plate Front Frame Holder Star Wheel Assy. Reinforcement Plate Holder Star Wheel PIS Sensor PIS FFC Holder Star Wheel PF Encoder Sensor Paper Guide Upper Spring (x3) Paper Guide Upper Assy. Holder Lever PE Assy. Head FFC Holder Cam Assy Spring Slider Cover ASF Drive Slider-Trans & Gear PF ScaleFrame Base Assy. Stacker Assy Ink System Assy Porous Pad Cap Lower PE SensorDisassembly/ReassemblyOverview43ConfidentialEPSON WF-3720 SeriesTable rd Operation TimeTime (mm:ss)Parts/UnitReplacement10:148:279:439:539:538:107:387:378:01Revision CAdjustment/inspection0:03------------------------Total10:178:279:439:539:538:107:387:378:01 Porous Pad Paper Guide Lower FAX Assy Shield Plate Fax Lower FAX Board Shield Plate Fax Upper Host USB Assy. Speaker Pickup Gear Shaft Drive PickupDisassembly/ReassemblyOverview44ConfidentialEPSON WF-3720 SeriesRevision C2.2 Common cautions when disassembling/reassembling the ProductThis section describes common cautions when disassembling/reassembling the disassembling/reassembling the printer including this product, be sure to read " Safety Precautions (p3)"

and this en

handling

handling new parts for replacement, take care not to contaminate

or damage disassembling/reassembling the parts, take care not to damage

the FFCs/cables/Ink tube if there is a possibility of coming into contact

with reassembling the product, take care not to let components of the

unit come installing parts, take care not to damage them when securing them

by tightening not lubricate any part other than those specified. If grease is applied on

such a part, wipe it off m visually that there are no scratches, dirt, and reassembling, confirm that there are no abnormal noises and they

work /

reassemblingWhen

applying

greaseExternal

partsMoving

care not to broke m that it is installed properly onto the transmissive sections of

the pinion gear/driven SensorsTake care not to damage care not to touch the detector for the encoder Sensor used with a circular scale, the photo sensor

section should be set over the encoded area of the circular care not to get injured by the sharp ends of the board terminal on

the back of the circuit boards when handling the sensors or the

peripheral care not to touch the encoded l it with the black triangular section down. (CR Scale only)Wipe off alcohol before installing. (CR Scale only)Confirm that they do not touch the photo sensors after installation.2.--- ink

care not to stain your hands with the waste ink soaked in the ink

pads. If ink comes into contact with your hands, wash it off with water

care not to stain the printer's parts with the waste ink soaked in the

ink pads. If ink comes into contact with the parts, wash it off.

(Especially, pay attention to Paper Guide Front/Lower Porous Pad)embly/ReassemblyCommon cautions when disassembling/reassembling the Product45ConfidentialEPSON WF-3720 sure to insert them to their connectors on the boards as far as they

will go without any loose connection such as a half-way or slant

them along their routing the double-sided tape that secures the FFCs is not strong enough to

secure them, make sure to replace the tape and secure the FFCs installing gears, pay attention to the following:•The gear section should not be damaged.•No foreign material is attached.•No grease is attached on any parts other than those not touch rollers for paper feeding when handling /IllustrationRevision C---Gears---PF rollersOne Time

partsADF/Scanner

UnitAfter removing One Time parts specified in this manual, do not reuse

them, but be sure to replace them with new ADF/SCN disassembly/reassembly, if you let go of the ADF/SCN Unit

with the hinge released, the unit may fall backwards, causing breakage,

therefore after removing the ADF/SCN Unit Hinge, take care to ensure the

unit is supported Time icon:

Ink care not to stain your hands with you connect the ink tube to another part, insert the ink tube up to

the root of the joint to prevent ink leakage and secure the tube with the

tube it's hard to insert the ink tube to the joint, apply CR02 to the inserting

part of the ink care not to stain or damage replacing the Housing Upper, transfer the MAC address label to

the new Left Frame.2.---MAC

Address

LabelLeft FrameDisassembly/ReassemblyCommon cautions when disassembling/reassembling the Product46ConfidentialEPSON WF-3720 SeriesRevision C2.3 Disassembly/Reassembly Procedures2.3.1 Functional differences between models and component partsIn "2.3.2 Disassembly Flowchart (p48)", the procedures are indicated on the premise that some parts/units are

removed in advance. Make sure to remove the following parts/units before starting disassembly.Cassette te ng the Cassette AssyAuto Duplex UnitAuto Duplex UnitFigure ng the Auto Duplex UnitDisassembly/ReassemblyDisassembly/Reassembly Procedures47ConfidentialEPSON WF-3720 SeriesRevision C2.3.2 Disassembly FlowchartThis section describes procedures for disassembling the parts/units in a flowchart format. For some parts/units,

detailed procedures or precautions are provided (accordingly indicated by icons and cell's color). Refer to the

explanations in the example chart below and perform an appropriate disassembling and assembling procedure.

(See "2.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit (p54)".)For routing cables, see "2.5 Routing FFCs/cables (p58)".The example below shows how to see the charts on the following name enclosed in gray

indicate a part/unit that

must be removed on the

way to the target necessary

procedures before

removing the following

parts.* Paper Guide

Upper Assy (p29)CR Timing BeltFFC/Cable * 1Printer

Mechanism---1S2Main Frame AssyWhite letters indicate a

part/unit supplied as

an the screw types

and the specified

torque in the “Screw

type/torque list”.Black letters indicate a

part/unit not supplied as

an ASP.--- (p 21) (p 27)4 (p 43) (p 22)

Reference pageNote"*":The boxes with only part names indicates the removal of such parts. If the names of FFCs or cables are

shown, disconnect the FFCs or cables from their rts/unit nameWhite-letterBlack-letterDescriptionPart/unit supplied as an ASPPart/unit not supplied as an ASPIndicates a practice or condition that could result in

injury or loss of life if not strictly tes a practice or condition that could result in

damage to, or destruction of equipment if not strictly

tes the parts that are inevitably broken in the

disassembling procedure, and should be replaced with a

new one for tes necessary check items in the disassembling/assembling nce------Indicates the reference

page in blue-letterIndicates the reference

page in blue-letter---Indicates the reference

page in blue-letterIndicates the reference

page in blue-letterIndicates the reference

page in blue-letterIndicates the reference

page in blue-letterChapter 3 " Adjustment

(p61)"Chapter 4 " Maintenance

(p80)"------IconIndicates supplementary explanation for disassembly is

tes particular tasks to keep quality of the units are

tes particular routing of cables is tes particular adjustment(s) is/are tes lubrication is tes the number of screws securing the parts/tes the points secured with other than a screw

such as a hook, rib, dowel or the embly/ReassemblyDisassembly/Reassembly Procedures48ConfidentialEPSON WF-3720 SeriesRevision C2.3.3.1Disassembly/Reassembly Flowchart

START1SCN Hinge

Screw (x1)CR Lock ReleaseGuide I/C---Housing Upper9S19S20(p 50)Pickup Roller

Assy---1---Holder Pickup---1---Paper Stopper

Assy2S1Cover-IF1S19Cover ADF Assy---2---Cover-ink-Eject1S19Holder CSIC

Assy---2------2---11 (p 80)------3 (p 54)CRCM Assy---Pickup Lever---------Pickup Roller---1---Ink Eject AssyPanel FFC x1Panel Board7Panel AssyS1S16S17S11---Cover Cable

Head Inner---2------2------3CSIC Connector

(x4)---S5------ (p 61) (p 58)

Housing Panel

UpperHousing Panel

Lower---5S1Printhead3S42Holder Tilt Left------------3 (p 61) (p 54)

Holder CSIC---------15---Screw type/torque listSymbolScrew TypeC.B.P-TITE SCREW,3X10,F/ZN-3CC.B.S-TITE SCREW,3X6,F/ZN-3CC.B.S-TITE SCREW,2X8,F/ZN-3CC.B.P-TITE SCREW,2.5X8,F/ZN-3CC.B.P-TITE SCREW,3X8,F/ZN-3CC.B.P-TITE SCREW,2.5X6,F/ZN-3CC.B.P-TITE (S-P1) SCREW,3X12,F/ZN-3CC.B.P-TITE SCREW,2X16,F/ZN-3CC.B.P-TITE SCREW,2X10,F/,3X4,F/,3X8,F/ZN-3CC.B.P-TITE SCREW,2X8,F/ZN-3CC.B.S-TITE SCREW,3X6,F/ZN-3CC.B.P-TITE SCREW,3X16,F/ZN-3CC.B.S-TITE SCREW,3X6,F/ZN-3CC.B.P-TITE SCREW,2.5X8,F/ZN-3CC.B.P-TITE.P2 SCREW,2.5X8,F/,3X8,F/ZN-3CC.B.P-TITE SCREW,3X10,F/,3X8,F/ZB-3CTorque6±1 kgf·cm6±1 kgf·cm4±1 kgf·cm4±0.5 kgf·cm6±1 kgf·cm4±0.5 kgf·cm6±1 kgf·cm2±0.5 kgf·cm2±0.5 kgf·cm4±1 kgf·cm8±1 kgf·cm3±0.5 kgf·cm8±1 kgf·cm13±1 kgf·cm4±1 kgf·cm5±0.5 kgf·cm6.5±0.5 kgf·cm8±1 kgf·cm6±1 kgf·cm6±1 kgf·cmNFC Board---S1---Power supply cable x1---S2S33S4S5S6Frame Right1S1---Power Supply

Unit------S7S8S9S10S11---SCN Hinge Assy3SCN FFC x2ADF PE Sensor Cable

S1 (p 61) (p 58)

S12S13S14---Rack Hinge

---1Box Gear Hinge

Assy---1--- (p 54)S15S16S17S18S192(p 50)---S20Flowchart embly/Reassembly Flowchart (1)Disassembly/Reassembly49Confidential

2023年12月8日发(作者：竭香巧)

SERVICE MANUALColor Inkjet PrinterEpson WF-3720 SeriesCONFIDENTIALSEMF16-010Notice:All rights reserved. No part of this manual may be reproduced, stored in a retrieval system, or transmitted in any form or

by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of

SEIKO EPSON CORPORATION.All effort have been made to ensure the accuracy of the contents of this manual. However, should any errors be

detected, SEIKO EPSON would greatly appreciate being informed of them.The contents of this manual are subject to change without notice.The above not withstanding SEIKO EPSON CORPORATION can assume no responsibility for any errors in this

manual or the consequences is a registered trademark of SEIKO EPSON :Other product names used herein are for identification purpose only and may be trademarks or registered

trademarks of their respective owners. EPSON disclaims any and all rights in those ght 2017SEIKO EPSON CORPORATIONP・CS Quality Assurance DepartmentConfidentialSafety PrecautionsAll safety procedures described here shall be strictly adhered to by all parties servicing and maintaining this

Strictly observe the following cautions. Failure to comply could result in serious bodily injury or loss of disconnect the product from the power source and peripheral devices when servicing the product or

performing performing works described in this manual, do not connect to a power source until instructed to do so.

Connecting to a power source causes high voltage in the power supply unit and some electronic components

even if the product power switch is off. If you need to perform the work with the power cable connected to a

power source, use extreme caution to avoid electrical GStrictly observe the following cautions. Failure to comply may lead to personal injury or loss of wear protective goggles for disassembly and reassembly to protect your eyes from ink in working. If

any ink gets in your eyes, wash your eyes with clean water and consult a doctor using compressed air products; such as air duster, for cleaning during repair and maintenance, the use

of such products containing flammable gas is TIONSStrictly observe the following cautions. Failure to comply may lead to personal injury or damage of the s on Epson product should be performed only by an Epson certified repair work should be performed on this product by persons unfamiliar with basic safety knowledge required for

power rating of this product is indicated on the serial number/rating plate. Never connect this product to

the power source whose voltages is different from the rated e malfunctioning components only with those components provided or approved by Epson;

introduction of second-source ICs or other non-approved components may damage the product and void any

applicable Epson capacitors on the Main Board may be electrically charged right after the power turns off or after driving

motors which generates counter electromotive force such as when rotating the PF Roller or when moving the

CR Unit. There is a risk to damage the Main Board if the Head FFC is short-circuited with the capacitors on

the Main Board electrically charged, therefore, after the power turns off or after motors are driven, leave the

printer untouched for approximately 30 seconds to discharge the capacitors before starting disassembly/ prevent the circuit boards from short-circuiting, be careful about the following when handling FFC or

cables.When handling FFC, take care not to let the terminal section of FFC touch metal parts.When connecting cables/FFC to the connectors on circuit boards, connect them straight to the connectors to avoid

slant order to protect sensitive microprocessors and circuitry, use static discharge equipment, such as anti-static

wrist straps, when accessing internal not tilt this product immediately after initial ink charge, especially after performing the ink charge several

times. Doing so may cause ink to leak from the product because it may take some time for the waste ink pads

to completely absorb ink wasted due to the ink touch the ink or wasted ink with bare hands. If ink comes into contact with your skin, wash it off with

soap and water immediately. If you have a skin irritation, consult a doctor disassembling or assembling this product, make sure to wear gloves to avoid injuries from metal parts

with sharp only recommended tools for disassembling, assembling or adjusting the e the specified torque when tightening extremely careful not to scratch or contaminate the following parts.Nozzle plate of the printheadCR ScalePF ScaleCoated surface of the PF RollerGearsRollersLCDScanner SensorExterior use oil or grease other than those specified in this manual. Use of different types of oil or grease may

damage the component or give bad influence on the printer the specified amount of grease described in this the specified adjustments when you disassemble the cleaning this product, follow the procedure described in this transporting this product after filling the ink in the printhead, pack the printer without removing the

ink cartridges in order to prevent the printhead from drying sure to install antivirus software in the computers used for the service support the virus pattern file of antivirus software disassembling/reassembling this product, if you find adhesive power of the double-sided tape which

secure the parts or FFC is not enough, replace the tape with new one and attach it correctly to the specified

points where the parts or FFC should be otherwise specified in this manual, the labels attached on the returned product should be transferred to

the corresponding attachment positions on the new one referring to the labels on the returned entialAbout This ManualThis manual, consists of the following chapters, is intended for repair service personnel and includes information

necessary for properly performing maintenance and servicing the R 1. TROUBLESHOOTINGDescribes the step-by-step procedures for the R 2. DISASSEMBLY / REASSEMBLYDescribes the disassembly/reassembly procedures for main parts/units of the product, and provides the

standard operation time for servicing the R 3. ADJUSTMENTDescribes the required adjustments for servicing the R 4. MAINTENANCEDescribes maintenance items and procedures for servicing the R 5. REFURBISHMENTDescribes refurbishing work of the product and its R 6. APPENDIXProvides the following additional information for reference:Connector DiagramProtection for TransportationSymbols Used in this ManualVarious symbols are used throughout this manual either to provide additional information on a specific topic or

to warn of possible danger present during a procedure or an action. Pay attention to all symbols when they are

used, and always read explanation thoroughly and follow the tes an operating or maintenance procedure, practice or condition that, if not strictly observed,

could result in serious injury or loss of tes an operating or maintenance procedure, practice, or condition that, if not strictly observed,

could result in bodily injury, damage or malfunction of indicate an operating or maintenance procedure, practice or condition that is necessary to

accomplish a task efficiently. It may also provide additional information that is related to a specific

subject, or comment on the results achieved through a previous Chapter 2 “Disassembly/Reassembly”, symbols other than indicated above are used to show additional

information for disassembly/reassembly. For the details on those symbols, see "2.3 Disassembly/Reassembly

Procedures (p47)".ConfidentialRevision StatusRevisionABDate of IssueMar 10, 2017May 26, 2017First ReleaseRevised□Chapter 2　■　Made change in "2.3 Disassembly/Reassembly Procedures (p47)"　　・　Made change in "2.3.3.1 Disassembly/Reassembly Flowchart (p49)"　■　Made change in "2.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit

(p54)"　　・　Made change in " Housing Upper (p54)"□Chapter 3　■　Made change in "3.2 Adjustment Program (p64)"　　・　Made change in "3.2.2 Adjustment and Inspection List (p64)"Revised□ Chapter 1　■ Made change in "1.3 Fatal Error Code List (p13)"　　・ Made change in "1.3.2.5 Printer (Head/CSIC) (p21)"　　　 “HCS error” has been added.□ Chapter 2　■ Made change in "2.1 Overview (p38)"　　・ Made change in "2.1.4 Standard Operation Time for servicing the product (p42)"　　　 “Stacker Support Front Assy” has been added.　■ Made change in "2.3 Disassembly/Reassembly Procedures (p47)"　　・ Made change in "2.3.3.1 Disassembly/Reassembly Flowchart (p49)"　　　 “Stacker Support Front Assy” has been added.　■ Made change in "2.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit (p54)"　　・ Made change in " SCN Hinge Assy (p54)"　　・ Made change in " Printer Mechanism (p56)"　　・ " Stacker Support Front Assy (p57)" has been added.　■ Made change in "2.5 Routing FFCs/cables (p58)"　　・ Made change in " Panel Assy (p58)"　　・ Made change in " ADF/SCN Unit (p58)"　　・ Made change in " Ink System (p58)"　　・ Made change in " Power Supply Unit (p58)"　　・ Made change in " Head FFC/CSIC FFC (p59)"　　・ Made change in " Speaker Cable (p60)"□ Chapter 3　■ Made change in "3.2 Adjustment Program (p64)"　　・ Made change in "3.2.2 Adjustment and Inspection List (p64)"　　・ Made change in "3.2.3 Details of the Adjustment Program (p69)" Made change in “PTS delay adjustment”.　■ Made change in "3.3 Mechanism Adjustment / Check (p76)"　　・ Made change in "3.3.1 Checking the Platen Gap (p76)"□ Chapter 5　■ Made change in "6.2 Protection for Transportation (p91)"　　・ "6.2.5 Preventing the shipping Liquid from leakage from Printhead (p95)" has been ptionCDecember 15,

2017ConfidentialEPSON WF-3720 SeriesRevision CContentsChapter 1 101.1. 101. 121.3Fatal Error 131.3.1Displaying the Fatal 131.3.2Fatal 141.3.2. 141.3.2.2Printer (CR)............................................................................................................................................ 171.3.2.3Printer (PF)............................................................................................................................................ 181.3.2.4Printer (I/S)............................................................................................................................................ 201.3.2.5Printer (Head/CSIC).............................................................................................................................. 211.3.2.6Printer (Others)...................................................................................................................................... 221.3.2. 231.4Service 241.4.1Status . 27Chapter 2 Disassembly/ 382. 382. 382.1.3Locations of the 392.1.4Standard Operation Time for servicing 422.2Common cautions when disassembling/reassembling 452.3Disassembly/ 472.3.1Functional differences between models and 472.3. 482.3.2.1Disassembly/ 492.4Detailed Disassembly/Reassembly Procedure for each 542.5Routing 58Chapter 3 Adjustment3. 623. 643.2. 643.2.2Adjustment and 643.2.3Details of the 693.3Mechanism Adjustment / 763.3.1Checking the . 763.3. 763.3.1.. 783.3.2MAC 79Chapter 4 . 814.1.1Cleaning the 817ConfidentialEPSON WF-3720 SeriesRevision C4.1.2Cleaning the Exterior Parts/inside of 834.2.1Lubrication Points 84Chapter 5 885.1. 88Chapter 6 Appendix6. 906.2Protection 916.2.1Securing the 916.2.2Securing the SCN/ 926.2.3Securing the 936.2.4Securing the ADF 946.2.5Preventing the shipping Liquid from leakage 958ConfidentialCHAPTER1TROUBLESHOOTINGConfidentialEPSON WF-3720 SeriesRevision C1.1 TroubleshootingThis section describes the troubleshooting workflow.1.1.1 Troubleshooting WorkflowThe following page describes the troubleshooting workflow. Follow the flow when troubleshooting problems.This flowchart is compiled based on the following contents.

•Our experience regarding the quality problem•ESK’s repair data•Printer Mechanism specification for WF-3720 SeriesIf the reason for the return is evident, first check the phenomenon user claims recurs,

then proceed to the hat is returned reason?Turn on the printerPrinter failure onlyADF/Scanner

unit failureCopy an imageDoes printer turn on the

power?YesNo1(p 11)Is scanning operation

finished without

trouble?YesNo5(p 11)Is Power-on sequence

finished without error?YesStandby conditionNo2(p 11)ADF failure?YesNoPrint check patternCopy an image by ADFIs printing operation

finished without error?YesNo3(p 11)Is ADF operation finished

without trouble?YesNo6(p 11)Is printing operation

finished without trouble?YesNo4(p 11)Finish**:In case of “Not Trouble Found”, check fatal error eshooting Workflow (1)TroubleshootingTroubleshooting10ConfidentialEPSON WF-3720 SeriesRevision C1The power-on

sequence does not

start (p 10)2Error is indicated during

power-on sequence (p 10)No Power*[Presumable Cause]•Power Supply Unit

damage•Main Board damage•Panel Unit damage[Major Troubleshooting]•Power Supply Unit

replacement•Main Board

replacement•Panel Unit replacementFatal error Please refer to " 1.3 Fatal Error

Code List (p13)" for

nance error[Occurrence Condition]This error occurs when

maintenance counter in

EEPROM exceeds the specified

value.[Major Occurrence Timing]•Power-on timing•Print start timing•Paper eject timing•Cleaning timing•Ink cartridge replacement

timing[Major Troubleshooting]•Replace Maintenance Box•Paper Guide Lower Porous

Pad replacement•Maintenance counter reset

(only Paper Guide Lower

Porous Pad)Paper Jam errorThis error occurs when printing

the nozzle check pattern. please

refer to " Paper Jam error".

Ink End error[Occurrence Condition]This error occurs when ink in Ink

cartridge is empty.[Major Occurrence Timing]•Power-on timing•Print start timing•Print timing•Cleaning timing•Ink cartridge replacement

timing[Major Troubleshooting]Ink cartridge replacement[NOTE]If an error occurs during printing,

the page where the error occurred is

skipped and the printing resumes

from the next cartridge detection error[Occurrence Condition]This error occurs when Ink

cartridge data is incorrect or Ink

cartridge is not recognized

correctly.[Major Occurrence Timing]•Power-on timing•Print start timing•Cleaning timing•Ink cartridge replacement timing[Major Troubleshooting]•Remove and reinstall Ink

cartridge.•Ink cartridge replacement•CSIC Terminal replacement•CR Contact Module

replacement•Head FFC replacement•Main Board replacementNo Ink cartridge error[Occurrence Condition]This error occurs when Ink

cartridge is not installed.[Major Occurrence Timing]At power-on[Major Troubleshooting]Install Ink cartridgeCR fixing material error[Occurrence Condition]When the printer moves to the

80-digit side during the power-on sequence before initial ink

charge, the printer detects

foreign material.[Major Occurrence Timing]Power-on timing(before initial ink charge)[Major Troubleshooting]Remove the CR fixing material,

and install the ink cartridge.* : If the printer can turn on but turns

off right away, the protection

circuit may cut off the power due

to an error such as a circuit

failure.3Error is indicated during printing nozzle check pattern (p 10)4Problems related to print result or during printing (p 10)5Scanning cannot be

performed

successfully (p 10)6ADF does not

operate

normally (p 10)Paper Jam error[Occurrence Condition]This error occurs when top/bottom of

paper is not detected by PE Sensor in the

specified steps of paper feeding

operation correctly.[Major Occurrence Timing]•Power-on timing•Paper loading timing•Paper eject timing•Duplex print timing[Major Troubleshooting]1Remove the jammed paper by

opening Scanner Unit or Printer

Cover.2Push “Start” button.3If not resolved by 2), check the

following.•Foreign material, bits of paper•Part come-off•PE Sensor Lever•PE Sensor•Float of Paper Guide Front Porous

Pad•Main Board•PW Sensor[NOTE]* If an error occurs during printing, the

page where the error occurred is skipped

and the printing resumes from the next

page.* If an error occurs during duplex

printing, the following are performed.•If an error occurs during the front

face of duplex printing, the page

where the error occurred and the

next page are skipped and the

printing resumes from the page

after the next.•If an error occurs during the back

face of duplex printing, the page

where the error occurred is skipped

and the printing resumes from the

next Paper error[Occurrence Condition]This error occurs when top of

paper is not detected by PE Sensor

in the specified steps of paper

loading operation correctly.[Major Occurrence Timing]Paper loading timing[Major Troubleshooting]1Put paper in cassette and push

“START” button.2If a paper stops before reaching

PE Sensor, remove it and

check the paper condition.3A)If no damage on the paper, set edge guide correctly after putting paper in cassette and push “PRINT” button again.B)If damage on the paper, check foreign materials / parts come- off / parts transformation in paper path.4If not resolved by 3-A) & 3-B),

check the following.•Pickup Roller•Duplex Unit•PE Sensor Lever•Main Board•PF Motor•Cassette AssyDouble Feed error/Stack col-lapsed error[Occurrence Condition]This error occurs on the following

cases.•A paper is ejected without

printing during paper loading

operation.•Actual paper length is longer

than theoretical one.

[Major Occurrence Timing]Paper loading timing[Major Troubleshooting]•Set the paper again.•PE Sensor Lever replacement•PE Sensor replacement•PW Sensor replacement•Main Board replacement[NOTE]This error occurs only for manual

duplex Size Unmatch error[Occurrence Condition]This error occurs when actual

paper size is not matched to

theoretical one.[Major Occurrence Timing]•Duplex print timing•FAX data print timing[Major Troubleshooting]1Put correct sized paper in

cassette, and push “START”

button.2If not resolved by step 1),

check the following points.•PE Sensor Lever•PE Sensor•PW Sensor•Main BoardNo Paper Cassette error[Occurrence Condition]This error occurs if one of the

cassettes is not installed.[Major Occurrence Timing]Paper loading timing (Front loading)[Major Troubleshooting]Install the Cassette Printing[Phenomenon]•Poor printing quality•Ink stain on paper•Dot missing•Paper eject without printing[Presumable Cause]•Driver / Panel mis-setting•Contamination of CR scale•Contamination of Printhead

Cover•Printhead damage•Ink clogging of Printhead•Contamination on Cap Unit /

Wiper of Ink system Assy•Ink system Assy damage•Float of Paper Guide Front

Porous Pad•Narrow PG•PE Lever damage•PE Sensor damage•PW Sensor damage[Major Troubleshooting]•Driver / Panel re-setting•CR Scale replacement•Printhead cover cleaning•Printhead cleaning•Ink cartridge replacement•Printhead replacement•Rubber cleaning of Cap Unit of

Ink system Assy•Ink system Assy replacement•Paper Guide Front Porous Pad

re-installation•PG readjustment•Printer Mechanism

replacement•PE Lever replacement•PE Sensor replacement•PW Sensor replacement•Main Board replacementPoor Paper Loading[Presumable Cause]•Use of 3rd party media•Edge guide mis-setting•Foreign material•Part come-off•Contamination of paper feed

roller (Duplex Unit)

•Cassette Assy damage•Pickup Roller deterioration,

contamination•Contamination of PF roller[Major Troubleshooting]•Recommendation of EPSON

media•Edge guide re-setting•Foreign material removal•Part re-installation•PF Roller replacement•Cassette Assy replacementAbnormal Noise[Presumable Cause]•Foreign material•Insufficient grease•Gear damage[Major Troubleshooting]•Foreign material removal

•Lubrication of grease•Gear replacementScanner failure[Presumable Cause]•Contamination of Scanner

Glass•Contamination of Document

Pad•CIS Unit bonding failure•CIS Unit damage•Scanner Motor damage[Major Troubleshooting]•Scanner Glass cleaning•Document Pad cleaning•Document Pad replacement•Scanner Unit replacementADF failure[Phenomenon]•No paper feed•Double feed•Paper jam•Paper skew[Presumable Cause]•Wear of Pickup Roller•Wear of ADF Pad Assy•Gear damage•Scanner Motor damage•Contamination of Scanner Glass•ADF Paper Support Assy

damage•Foreign material•ADF Cover Assy damage•Wear of EJ Roller•ADF Sensors damage[Major Troubleshooting]•ADF Cover Assy replacement•ADF Pad Assy replacement•Scanner Glass cleaning•ADF Paper Support Assy

replacement•Foreign material removal•Scanner Unit replacement•ADF Unit replacementFigure eshooting Workflow (2)Troubleshooting11ConfidentialEPSON WF-3720 SeriesRevision C1.2 Power-On SequenceThis section describes the power-on sequences for this product. The preconditions are as follows.Normal power-on sequence (See Table 1-1.)Turning on the printer after turning it off without an error and the power was turned off normally at the previous

shut l ink charge has finished and every cartridge has sufficient paper on the paper Printhead is capped by the cap of the Ink Lock is engaged nance error recovery has never been -on ead initialization*lizes the Printhead, and inspect the Unit/Cap Unit movement

and position*1㻤㻜㻯㻾㻌㼁㼚㼕㼠㻴㻼㻜㻯㻾㻌㻸㼛㼏㼗 ink overflow the waste ink counter if the waste ink overflow is occurring.㻤㻜㻴㻼㻜g the home CR Unit moves to the 0-digit side slowly and confirms it touches the Right regarding the position where the CR Unit touches the Right Frame as the specified distance from the origin, the

home position is determined. Thereafter, the position of the CR Unit is monitored based on the information

provided by the CR Encoder CR Unit slowly moves to its home position.㻤㻜㻴㻼㻜㻤㻜㻴㻼㻜㻤㻜㻴㻼㻜 temperature operation sequence*es the CR CR Unit moves back and forth between near the Home Position and near the Left Frame for two times.㻤㻜㻴㻼㻜㻤㻜㻴㻼㻜ing ink cartridge and initializing ink system* check the operation of the PIS Sensor, the CR Unit moves back and forth from around the CR lock to the middle

of the printer 2 times while passing over the PIS Sensor.㻤㻜㻴㻼㻜 lock setting

Cap rises to set the CR lock.

㻤㻜㻴㻼㻜Note*1:The conditions of the CR lock are as :CR lock is setWhite:CR lock is released*2:If it cannot be initialized, the fatal error occurs.*3:Executed when the detected temperature is under 5 oC (41oF) by the thermistor on the Printhead.*4:The cleaning or empty suction operation may occur depending on eshootingPower-On Sequence12ConfidentialEPSON WF-3720 SeriesRevision C1.3 Fatal Error Code ListThis section describes how to check the fatal error code, description, and the possible causes.1.3.1 Displaying the Fatal Error CodeThe fatal error code is stored in the EEPROM on the Main Board and can be read out using the Adjustment

Program. This product displays a printer fatal error code automatically on the panel LCD when a printer fatal

error display screen imageError CodeFigure ying the Fatal Error CodeTroubleshootingFatal Error Code List13ConfidentialEPSON WF-3720 SeriesRevision C1.3.2 Fatal Error CodeThis section describes the fatal error code and the possible cause for this product." ADF/Scanner (p14)"" Printer (CR) (p17)"" Printer (PF) (p18)"" Printer (I/S) (p20)"" Printer (Head/CSIC) (p21)"" Printer (Others) (p22)"" System Error (p23)"1.3.2.1ADF/ScannerError

codeError namePossible causeThe scanner CR could not return to its or disengaging of wheel train of the

drive aging, fraying, jumping of the timing beltFailed to read the white standard/home nection, break, skew or damage of the

scanner e of the CIS e of the scanner e of the main boardThe scanner CR cannot completely reach the home

(left side) or disengaging of wheel train of the

drive mechanismFailed to read the scanner or skew of the scanner e of the CIS e of the scanner e of the main boardThe scanner CR cannot completely reach the

opposite side of the home (right side)

or disengaging of wheel train of the

drive mechanismFailed to read the scanner or skew of the scanner e of the CIS e of the scanner e of the main boardOverload of the scanner drive mechanismFailure of the scanner motor

100020Measurement

errorConfirmation the document cover opened, turn the

power if the CIS moves to the left to read

the white standard/home if the CIS's emission color is white

(not greenish, reddish, or bluish).If the light does not look like white, check

the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new the document cover opened, turn the

power if the CIS (CR) reaches (comes in

contact with) the left the wheel train of the drive

mechanism for the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new the document cover opened, turn the

power if the CIS (CR) reaches (comes in

contact with) the right the wheel train of the drive

mechanism for the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new if the CIS (CR) moves or not.1)Check the timing belt for fraying or

looseness.2)Check the wheel train of the drive

mechanism for e the scanner unit with a new e the main board with a new the color of the LED at the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new tor

No.100016HP detection

failureMain boardCN804CN801100017Contact

detection

distance

exceededMain boardCN804CN801100018Opposite side

contact

detection

distance

exceeded errorMain boardCN804CN801---100032LED light

failureFailure of the CIS LED light (RGB)nection, break, skew or damage of the

scanner e of the CIS e of the main boardMain boardCN801TroubleshootingFatal Error Code List14ConfidentialEPSON WF-3720 SeriesError

codeError namePossible causeNo jammed paper is remaining but the sensor does

not turn e of the ADF PE e of the cableJammed paper is remainingThe paper feed rollers and paper conveying rollers

slip too muchAt power-on, during paper feed, during scanningRevision CConfirmation the Cover,Paper Guide,LD,ADF and

check if paper exist or the Document Support ADF and

check if paper exist or the ADF and check if paper exist or

if the paper sensor lever moves up

and e the ADF unit with a new e the scanner unit with a new e the main board with a new the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new tor

No.100054Paper jam errorMain boardCN802100065FB PID excess

speed errorFailed to read the scanner ination of the scanner encoder or skew of the scanner e of the scanner encoder sensorFailure of the scanner motor e of the main boardOperation failure of the scanner scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner ination of the scanner or skew of the scanner e of the scanner encoder e of the main boardThe scanner motor did not scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the CR motor ination of the scanner or skew of the scanner e of the scanner encoder e of the scanner motor

e of the main boardThe scanner motor did not scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner motor ination of the scanner or skew of the scanner e of the scanner encoder e of the scanner motor

e of the main boardThe scanner motor stopped running in the middle of

the scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner motor ination of the scanner nection, break, skew or damage of the

scanner e of the scanner encoder e of the scanner motor

e of the main boardMain the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new one.100066FB PID reverse

errorMain the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100067FB PID lock

the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100068FB PID

acceleration

lock the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100069FB PID excess

load errorTroubleshootingFatal Error Code List15ConfidentialEPSON WF-3720 SeriesError

code100070Revision CPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new nameFB PID driving

time errorConnector

No.---Malfunction or crash of the firmwareFailed to read the scanner ination of the scanner encoder or skew of the scanner e of the scanner encoder sensorFailure of the scanner motor e of the main boardOperation failure of the scanner scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner ination of the scanner or skew of the scanner e of the scanner encoder e of the main boardThe scanner motor did not scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the CR motor ination of the scanner or skew of the scanner e of the scanner encoder e of the scanner motor

e of the main boardThe scanner motor stopped running in the middle of

the scanning operation was stopped by;•Disengaging of the scanner CR•Disengaging of the scanner motor pulley or

cracking of the scanner motor gearsFailed to read the scanner motor ination of the scanner nection, break, skew or damage of the

scanner e of the scanner encoder e of the scanner motor

e of the main boardMalfunction or crash of the firmware100073FB BS+ excess

speed errorMain the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new one.100074FB BS+

reverse errorMain the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100075FB BS+ lock

the scanner FFC for damage,

disconnection or e the scanner unit with a new e the main board with a new boardCN804CN801100077FB BS+ excess

load error100078FB BS+

driving time

the printer off and back it the error still occurs after the restart,

replace the main board.---TroubleshootingFatal Error Code List16ConfidentialEPSON WF-3720 SeriesRevision C1.3.2.2Printer (CR)Error

code000020Error nameCR PID

driving time

errorPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main that no obstacle exist in the CR

motion the CR lock and ink system for any

the timing belt for fraying or

the load applied to the CR by

moving it by if the lubricant on the CR shaft is the CR drive the CR encoder scale if it is

e the CR motor with a new e the main board with a new the CR encoder scale if it is

the FFC of the CR e the CR encoder sensor with a new

e the main board with a new that no obstacle exist in the CR

motion range.

the CR lock and ink system for any

the timing belt for fraying or

the CR encoder scale if it is

the CR encoder FFC or the

e the CR encoder sensor with a new e the main board with a new that no obstacle exist in the CR

motion range.

the CR by hand to see if it moves

smoothly without getting the timing belt for fraying or

the CR encoder scale if it is

the connector and the CR encoder

FFC for e the CR encoder FFC with a new the connector of the CR e the CR motor with a new e the main board with a new that no obstacle exist in the CR

motion range.

the CR lock and ink system for any

the timing belt for the CR encoder scale if it is

the connector of the CR encoder

e the CR motor with a new e the main board with a new tor

No.---Malfunction or crash of the firmwareThe CR motor stopped running in the middle of the

CR was stopped by;•Obstacles such as jammed paper•Overload of the mechanism•Interfere with the ink system•Disengaging, fraying, jumping of the timing belt•Crack or disengaging of the gear, or the APG

lever interferes with the CRFailed to read the CR ination of the CR encoder e of the CR motor (not completely broken)e of the main boardFailed to read the CR ination of the CR encoder or skew of the CR encoder e of the CR encoder sensorFailure of the CR motor e of the main boardOperation failure of the CR motor, stopped by

was stopped by;•Obstacles such as jammed paper•Interfere with the ink system•Disengaging or breakage of the gearsFailed to read the CR g of the CR timing ination of the CR encoder or skew of the CR encoder e of the CR encoder e of the main boardThe CR motor did not run, or the CR could not move

ad of the CRFailed to read the CR timing belt become frayed or ination of the CR encoder nection, break, skew or damage of the CR

encoder e of the CR encoder e of the CR motor (the lead wire is broken

or the connector is disconnected)e of the main board000021CR PID excess

load error---000022CR PID excess

speed errorMain boardCN702CN608000023CR PID

reverse errorMain boardCN702CN608000024CR PID lock

errorMain boardCN702CN608000025CR PID speed

fall errorOperation failure of the CR was stopped by;•Obstacles such as jammed paper•Overload of the mechanism•Interfere with the ink systemFailed to read the CR motor timing belt become loosened or ination of the CR encoder or skew of the CR encoder e of the CR motor

e of the main boardMain boardCN702CN608TroubleshootingFatal Error Code List17ConfidentialEPSON WF-3720 SeriesError

codeError nameCR load

position

driving time

errorRevision CPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main that no obstacle exist in the CR

motion range.

the CR lock and ink system for any

the timing belt for fraying or

the load applied to the CR by

moving it by if the lubricant on the CR shaft is

the CR drive the CR encoder scale if it is

e the CR motor with a new e the main board with a new the CR encoder scale if it is

the FFC of the CR e the CR encoder sensor with a new

e the main board with a new that no obstacle exist in the CR

motion range.

the CR lock and ink system for any

the timing belt for fraying or

the CR encoder scale if it is

the CR encoder FFC or the

e the CR encoder sensor with a new

e the main board with a new tor

No.000030Malfunction or crash of the firmware---000031CR load

position excess

load errorThe CR motor stopped running in the middle of the

CR was stopped by;•Obstacles such as jammed paper•Overload of the mechanism•Interfere with the ink system•Disengaging or breakage of the gears•Disengaging, fraying, jumping of the timing

beltFailed to read the CR ination of the CR encoder e of the CR motor (not completely broken)e of the main boardMain boardCN702CN608000032CR load

position excess

speed errorFailed to read the CR ination of the CR encoder or skew of the CR encoder e of the CR encoder sensorFailure of the CR motor e of the main boardOperation failure of the CR motor, stopped by

was stopped by;•Obstacles such as jammed paper•Overload of the mechanism•Interfere with the ink systemFailed to read the CR g of the CR timing ination of the CR encoder or skew of the CR encoder e of the CR encoder e of the main boardMain boardCN702CN608000033CR load

position

reverse errorMain boardCN702CN6081.3.2.3Printer (PF)Error

codeError namePossible causeMalfunction or crash of the firmwareThe PE sensor remains in paper detection status and a

paper jam error occurs instead of causing a fatal

error.The PF motor stopped running in the middle of the

PF was stopped by;•Obstacles such as jammed paper•Overload of the paper feed mechanism•Disengaging or breakage of the gearsFailed to read the PF motor timing belt become frayed or ination of the PF encoder nection, break, skew or damage of the PF

motor cable/encoder e of the PF motor (not completely broken)e of the main boardConfirmation the printer off and back it the error still occurs after the restart,

replace the main that no pieces of paper or foreign

objects exist in the paper the load of the paper feed

the wheel train of the PF drive and

the timing belt for fraying or the PF encoder scale for damage or

the PF encoder FFC or the

e the PF motor with a new e the main board with a new tor

No.000040PF PID driving

time error---000041PF PID excess

load error---TroubleshootingFatal Error Code List18ConfidentialEPSON WF-3720 SeriesError

codeError namePossible causeFailed to read the PF motor ination of the PF encoder or damage of the PF encoder e of the PF encoder sensorFailure of the PF motor e of the main boardPaper feed fails, stopped by feed was stopped by;•Obstacles such as jammed paper•Overload of the paper feed mechanism•Disengaging or tooth breakage of wheel train

of the paper feed mechanismFailed to read the PF motor g of the PF timing ination of the PF encoder or damage of the PF encoder e of the PF encoder e of the main boardThe PF motor did not run or obstacles exist in the

paper ad of the paper feed PF timing belt become frayed, jumping, or

the wheel train of paper feed mechanism is

disengaged or its tooth is brokenFailed to read the PF motor ination of the PF encoder nection, break, skew or damage of the PF

encoder e of the PF encoder e of the PF motor (the lead wire is broken

or the connector is disconnected)e of the main boardRevision CConfirmation the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new

e the main board with a new that no pieces of paper or foreign

objects exist in the paper the load of the paper feed

the wheel train of the PF drive and

the timing the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new

e the main board with a new that no jammed paper exist in the

paper the load of the the wheel train of the PF drive and

the timing belt for fraying or the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new

the connector of the PF e the PF motor with a new e the main board with a new the printer off and back it the error still occurs after the restart,

replace the main that no pieces of paper or foreign

objects exist in the paper the load of the paper feed

the wheel train of the PF drive and

the timing belt for fraying or the PF encoder scale if it is

e the PF motor with a new e the main board with a new the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new e the main board with a new tor

No.000042PF PID excess

speed errorRelay boardCN703CN502000043PF PID reverse

errorRelay boardCN703CN502000044PF PID lock

errorRelay boardCN703CN502000050PF load

position

driving time

errorMalfunction or crash of the firmware---000051PF load

position excess

load errorThe PF motor stopped running in the middle of the

PF was stopped by;•Obstacles such as jammed paper•Overload of the paper feed mechanism•Disengaging or breakage of the gearsFailed to read the PF motor g of the timing ination of the PF encoder e of the PF motor (not completely broken)e of the main boardFailed to read the PF motor ination of the PF encoder or damage of the PF encoder e of the PF encoder sensorFailure of the PF motor e of the main board---000052PF load

position excess

speed errorRelay boardCN703CN502TroubleshootingFatal Error Code List19ConfidentialEPSON WF-3720 SeriesError

codeError namePossible causePaper feed fails, stopped by feed was stopped by;•Obstacles such as jammed paper•Overload of the paper feed mechanism•Disengaging or tooth breakage of wheel train

of the paper feed mechanismFailed to read the PF motor g of the PF timing ination of the PF encoder or damage of the PF encoder e of the PF encoder e of the main boardRevision CConfirmation that no pieces of paper or foreign

objects exist in the paper the load of the paper feed

the wheel train of the PF drive and

the timing belt for fraying or the PF encoder scale if it is

the PF encoder FFC or the

e the PF encoder sensor with a new e the main board with a new tor

No.000053PF load

position

reverse errorRelay boardCN703CN5021.3.2.4Printer (I/S)Error

code000100Error nameIS PID driving

time errorPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for disengage or the I/S encoder scale if it is

e the ink system with a new e the main board with a new the I/S encoder scale if it is

the I/S encoder FFC or the

e the ink system with a new e the main board with a new the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for tooth breakage or the I/S encoder scale if it is

the cable/FFC of the I/S motor/e the ink system with a new e the main board with a new the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for tooth breakage or the I/S encoder scale if it is

the cable/FFC of the I/S motor/e the ink system with a new e the main board with a new tor

No.---Malfunction or crash of the firmwareThe I/S motor stopped running in the middle of the

ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gearsFailed to read the I/S ination of the I/S encoder e of the I/S motor (not completely broken)e of the main boardFailed to read the I/S motor ination of the I/S encoder or skew of the I/S encoder e of the I/S encoder sensorFailure of the I/S motor e of the main boardOperation failure of the I/S motor, stopped by

ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gearsFailed to read the I/S ination of the I/S encoder or skew of the I/S motor cable/encoder

e of the I/S encoder e of the main boardThe I/S motor did not ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gearsFailed to read the I/S ination of the I/S encoder , skew or damage of the I/S motor cable/encoder e of the I/S encoder e of the I/S motor (the lead wire is broken

or the connector is disconnected)e of the main board000101IS PID excess

load error---000102IS PID excess

speed errorMain boardCN701CN508000103IS PID reverse

errorMain boardCN701CN508000104IS PID lock

errorMain boardCN701CN508TroubleshootingFatal Error Code List20ConfidentialEPSON WF-3720 SeriesError

codeError nameIS load

position

driving time

errorRevision CPossible causeConfirmation the printer off and back it the error still occurs after the restart,

replace the main the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for disengage or the I/S encoder scale if it is

e the ink system with a new e the main board with a new the I/S encoder scale if it is

the I/S encoder FFC or the

e the ink system with a new e the main board with a new the load applied to the I/S motor by

moving it by the wheel train of the ink system

drive for tooth breakage or the I/S encoder scale if it is

the cable/FFC of I/S motor/e the ink system with a new e the main board with a new tor

No.000110Malfunction or crash of the firmware---000111IS load

position excess

load errorThe I/S motor stopped running in the middle of the

ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gearsFailed to read the I/S ination of the I/S encoder e of the I/S motor (not completely broken)e of the main boardFailed to read the I/S ination of the I/S encoder or skew of the I/S encoder e of the I/S encoder sensorFailure of the I/S motor e of the main boardOperation failure of the I/S motor, stopped by

ink system was stopped by;•Overload of the mechanism•Disengaging or breakage of the gears Failed to read the I/S ination of the I/S motor encoder or skew of the I/S motor cable/encoder

e of the I/S encoder e of the main boardMain boardCN701CN508000112IS load

position excess

speed errorMain boardCN701CN508000113IS load

position

reverse errorMain boardCN701CN5081.3.2.5Printer (Head/CSIC)Error

codeError namePossible causeDisconnection, break, skew or damage of the head

FFCOverheat of the e of the e of the main boardOccurs in-between print passes (after printing

one pass and before printing the next pass)Disconnection, break, skew or damage of the head

FFCOverheat of the e of the e of the main boardOccurs every after ink flushing operation(Flushing before starting printing, flushing

after manual cleaning and etc.)Failure of the main boardOccurs after receiving a print job and starting

printingDisconnection, break, skew or damage of the head

FFCOccurs after receiving a print job and starting

printingFailure of the thermistor inside the printheadTemperature around the printhead is out of the

range from -20 to 80 degrees mation the head FFC for disconnection,

break, skew or e the printhead with a new e the main board with a new tor

No.031001HeadHot

detect error

(pre printing)Main boardCN606CN607CN608031002HeadHot

detect error

(after flushing) the head FFC for disconnection,

break, skew or e the printhead with a new e the main board with a new boardCN607031003Transistor

temperature

errorReplace the main board with a new the head FFC for disconnection,

break, skew or e the printhead with a new e the main board with a new one.---031004Head

temperature

errorMain boardCN607TroubleshootingFatal Error Code List21ConfidentialEPSON WF-3720 SeriesError

codeError namePossible causeFailure of the power source for the e of the circuitDisconnection, break, skew, or damage of the

head t of fuse on the main boardFailure of the printheadOccurs at power-on, when replacing the ink

cartridge, in-between print passes, and after

flushing FFC failure (skew, foreign object attached)e of the e of the main board(Occurrence frequency based on past record is 1. > 2.

> 3.) FFC failure (skew, foreign object attached)e of the e of the main boardFailure of the main boardOccurs at power-on, and during operation for

replacing the ink cartridgeError in the printer settingsFailure of the main boardOccurs at power-onRevision CConfirmation the fuse has not blown out1)Check the head FFC for disconnection,

break, skew or the fuse has blown out1)Replace the main board with a new the other cases1)Replace the printhead with a new tor

No.031006Blowout of a

fuse error

(Head)Main boardCN606031008VBS

overvoltage

the head e the printhead with a new e the main board with a new boardCN606031011HCS the head e the printhead with a new e the main board with a new the CRCM FFC for disconnection,

break, skew or the error still occurs after the restart,

replace the main the printer off and back it the error still occurs after the restart,

replace the main boardCN606033001Blowout of a

fuse error

(CRCM)Other Ink

device errorOther Ink

device errorOther Ink

device errorCRCM access

error

(Hard factor)CRCM access

error

(Hard factor)Main boardCN604033005-----033006Disconnection, break, skew or damage of the CRCM

FFCFailure of the CSIC terminal/CR contact moduleFailure of the main the CRCM FFC for disconnection,

break, skew or the error still occurs after the restart,

replace the main boardCN610CSIC access

error

(Hard factor)Disconnection, break, skew or damage of the CRCM

FFCFailure of the CSIC terminal/CR contact moduleFailure of the main board (mismatch of the printer

settings that cannot be changed when repairing the

printer)Occurs at the CRCM FFC for disconnection,

break, skew or the error still occurs after the restart,

replace the main boardCN6081.3.2.6Printer (Others)Error

code033501Error nameILS

environmental

errorILS continuous

reflected light

errorILS no

reflected light

errorILS shift

length errorILS Empty Jig

errorPossible causeConfirmation the sensor is directly exposed to light,

block out the light.

e the PIS sensor with a new e the jig I/e the PIS sensor with a new e the PIS sensor FFC with a new

e the PIS sensor with a new e the I/C with a new e the jig I/e the PIS sensor with a new e the jig I/e the PIS sensor with a new tor

No.---The PIS sensor received unexpected amount of lightThe PIS sensor received unexpected amount of

reflected light from the jig I/CAnti-reflection film of the I/C has been removedElectric voltage for the PIS sensor is insufficient•Break of the FFC•The PIS sensor has deteriorated•Reflected light from the I/C is insufficient At power-on, during replacing I/CPositioning of the I/C and the PIS sensor is from Empty jig I/C is insufficient033502---033503

Main boardCN505------TroubleshootingFatal Error Code List22ConfidentialEPSON WF-3720 SeriesError

code033506Revision CPossible causeLight from Full jig I/C is too muchElectric voltage for the PIS sensor is insufficient•Break of the FFC•The PIS sensor has deteriorated•Reflected light from the I/C is insufficientAt power-on, during replacing I/C, during

switching APGThis error code is not displayed but the error history is

saved.The carriage does not ad of the carriage drive mechanism (paper

jam, foreign object)e of the ink e of the CR e of the main boardError nameExcessive

Light errorConfirmation e the jig I/e the PIS sensor with a new e the I/C with a new e the PIS sensor with a new tor

No.---033507Insufficient

Light errorMain boardCN506034001Home position

that no obstacle exist in the

carriage motion ly unlock the carriage. (If

unlocking is impossible, the problem

caused by failure of the ink system.)

the load applied to the CR by

moving it by the printer on and check if the carriage

moves. If it still does not move, the motor is

broken or failure of the main board.---034500Ink cartridge

replacement

timing contact

detection errorDriver

mismatch errorBecause the I/C is not securely installed, it comes in

contact with the housing.Non-supported printer driverMismatch between custom printer driver and custom

l the I/C securely.---060002Check the OS and the version of the printer

driver.---1.3.2.7System ErrorError

code2026202xxxxxError nameWi-Fi Board

failureFirmware bugPossible causeFailure or disconnection of the wireless network boardAn error code will be assigned to each firmware internal

error as mation procedure•Check the wireless network board.•Check the FFC.•Firmware version•Main boardConnector

boardCN301---TroubleshootingFatal Error Code List23ConfidentialEPSON WF-3720 SeriesRevision C1.4 Service Support ModeOverviewService support mode is a service dedicated special mode that can be started by a special operation, and allows

you to execute functions including adjustment, inspection, and individual operation check SW

SW1Touch Panel Left [LEFT]Touch Panel Right [RIGHT]Touch Panel Center [CENTER]Figure operation on Service Support ModeService Support Mode startup and operating the [SW1] and [Power SW] button until the screen switches, starting the pressing the Touch Panel, ensure that an object at least 20 mm(L) × 25 mm(W) × 2

mm(H) in size is used. (E.g. Press with a finger diagonally)Power SW

SW1Figure e Support Mode startup and operating proceduresTroubleshootingService Support Mode24ConfidentialEPSON WF-3720 e the Touch Panel, and enter the to enter: 49515Operating the Touch Panel right [RIGHT] until the value you wish to input is on the Touch Panel left [LEFT] to check the value. The value will change to “*”, and await entry of

the next steps 1 and 2 to enter the 5 digit entry is completed, tap the Touch Panel center [CENTER] to :[Right]SHIFT:[Left]/FIN:[Center] **5Touch Panel Left [LEFT]Touch Panel Right [RIGHT]Touch Panel Center [CENTER]Figure e Support Mode operating procedureIt is not possible to return to the previous digit after shifting digits. If you wish to correct

the number of the previous digit, proceed with the steps until after step 5 and then

perform input again.Please note that the execute button is not enabled until at least two digits have been

on if enter and execute the wrong IDWhen a different mode starts:If you enter the wrong ID and a different mode starts, there is the possibility of changing

important settings of the unit, so press the power button to turn off the power

immediately and then perform the process again to enter the correct ID number.When non-existent ID number:The following panel LCD display appears and the power is turned off ID is not found!!Please TroubleshootingService Support Mode25ConfidentialEPSON WF-3720 SeriesService Support Mode menu configurationMaintenance SP Mode　Run:Center / Select:r Inspection Sheet Print Log Get Lock CheckRevision CFigure e Support Mode: Top Menu ScreenItemPrinter modeDisplayPrinter Inspection ModeOverviewUsage situationWith the ADF/SCN Unit removed, you

Repair workingcan carry out adjustment addition to checking confirming

normal status sheet information, you

Troubleshootingcan also check information required for

performing analysis, copy the user

log data to external storage media such as

Troubleshootinga USB memory device connected to the

main replacing after return, or

Repair workingcompleting repairs, you can check if the

TroubleshootingCR lock is e status sheet printStatus Sheet Print ModeUser log data get modeUser Log Get ModeCR lock checkCR Lock CheckTroubleshootingService Support Mode26ConfidentialEPSON WF-3720 SeriesRevision C1.4.1 Status Sheet InformationThe following status sheets can be printed from the section explains about each item printed on the status sheets.Overview of Status SheetsPrinter Information SheetSupply Status Sheet

Usage History SheetService Status SheetStatus Sheet ItemsPrinter information sheet (total pages: 6 sheets)ItemDevice IDSerial NumberMAC AddressMemory CapacityHardware

ConfigurationCard Reader StatusFirmwareMain FirmwareNetwork FirmwareQPITExplanationDevice ID (product name) is serial number of the product is address of the product is ty of the memory inside the product is

tion condition of a device for user

authentication is n of the firmware is n of the main firmware is n of the NW firmware is n of the QPIT is current language setting is setting of mute (on/off) is displayed.: printer settings information: supported model numbers of consumables or periodic replacement parts, and the total number of sheets fed into the printer.: usage history such as the total number of printed pages per function.: in addition to the information included in the above three sheets,

information required for servicing is also provided.Basic settingsLanguageMuteButton PressError NoticeReceive Completion

NoticeSend Completion NoticePrint Completion NoticeRing ToneReceiverSound Type

settings>NormalSound level setting (0 to 10) is timer settingPower Off TimerUSB I/F Timeout SettingPrinting LanguageAuto Error SolverMemory DeviceMemory Device

InterfaceFile SharingUSBNetworkWhether the sleep timer is enabled or not is

displayed. When enabled, the time period before the

product enters sleep mode is also Power Off Timer setting is I/F time out settings are language settings are r the auto error resolver options are enabled

or not is r the external memory setting is enabled or

not is file sharing setting (which connection way of

computers, USB or network, is allowed to access the

external memory) is displayed.

The Ink Drying Time when duplex printing is

r the setting is enabled or not is r the setting is enabled or not is Drying TimePC connection via USBNFCTroubleshootingService Support Mode27ConfidentialEPSON WF-3720 SeriesItemPaper cassette 1 to

Paper cassette 4MP trayPaper SizePaper TypePaper Size Auto DetectPaper SizePaper TypeExplanationRevision CPaper cassettePaper size and type settings of each of the cassettes

and whether the auto paper size detection feature is

enabled or not are r the auto switching function is enabled or

not is displayed.A4/Letter Auto SwitchingPaper

source

settingsAuto

Selection-CopyAuto

Selection-FaxAuto

Selection-OtherAuto Selection-CopyAuto Selection-FaxAuto Selection-OtherRear Paper Feed PriorityPaper Size NoticePaper Type NoticeTop OffsetLeft OffsetTop Offset in BackLeft Offset in BackCheck Paper WidthSkip Blank PagePaper SizePaper TypeOrientationQualityInk Save ModePrint OrderNumber of CopiesBinding MarginAuto Paper Ejection2-Sided PrintingFont SourceFont NumberPitchHeightSymbol SetFormCR FunctionLF FunctionPaper Source AssignError SheetColorationBinaryPDF Page SizePCLPSPDFPaper cassette 1 to paper

cassette 2, MP trayPaper cassette 1 to paper

cassette 2, MP trayPaper cassette 1 to paper

cassette 2, MP trayWhether the auto paper source selection setting for

each of the functions is enabled or not is r the setting is enabled or not is r the setting is enabled or not is r the setting is enabled or not is settingsUniversal Print

SettingsThe offset setting (-30 to 30) is r the setting is enabled or not is r the setting is enabled or not is size setting is type setting is orientation setting (portrait or landscape) is

print quality setting (Draft, Standard, or Best) is

displayed.

Whether the setting is enabled or not is print order setting (print from the first page or

last page) is rd number of copies (1 to 999) is Binding Margin is r the setting is enabled or not is r the setting is enabled or not is Print

ConfigurationThe Setting of PCL Menu is displayed.Whether the setting is enabled or not is color setting (Color or Mono) is r the setting is enabled or not is PDF paper size setting is version of each of the printer language is

displayed.TroubleshootingService Support Mode28ConfidentialEPSON WF-3720 SeriesItemSubject (“Scan to Email” only)ColorFile FormatDocument Open Password (not provided for “Scan

to Cloud”)Permissions password (not provided for “Scan to

Cloud”)PrintingEditingResolution (not provided for “Scan to Cloud”)2-SidedBinding Position

Email>

Network

Folder/FTP>

Memory

Device>

Cloud>Scan areaRemove shadowSurroundCenterRemove Punch HolesErasing PositionRevision CExplanationThe subject of email is color setting (Color or Mono) is format setting is r the password setting is enabled or not is

r the password setting is enabled or not is

r printing scanned document is permitted or

not is r editing scanned document is permitted or

not is resolution setting is r the 2-sided scanning is enabled or not is

g position of documents (left/top/--- (in case

of one-side scanning)) is al document size setting is r the setting is enabled or not is frame width setting (0 to 40 mm/---(in case of

the shadow remove setting is disabled)) is center width setting (0 to 40 mm/---(in case of

the shadow remove setting is disabled)) is r the setting is enabled or not is erasing setting (left edge/right edge/top edge/bottom edge/--- (in case of the remove punch holes

setting is disabled)) is erasing amount (0 to 20 mm/--- (in case of the

remove punch holes setting is disabled)) is

document orientation setting (portrait or

landscape) is quality setting (Text/Text & Image/Photo) is

displayed.

The density setting (-4 to 4) is name prefix setting for scanned file is r the setting is enabled or not is r the setting is enabled or not is Compression Ratio is maximum file size that can be attached to an

email is r the setting is enabled or not is r the setting is enabled or not is version is product key is displayed (“---” is displayed

when it is not set).Scan

settingsErase AmountOrientation (Original)Document TypeDensityFilename Prefix (not provided for “Scan to

Cloud”)DateTime of DayCompression Ratio (not provided for “Scan to

Cloud”)Attached File Max Size (“Scan to Email” only)Admin SettingsEpson Open Platform

InformationLock SettingAccess ControlVersionProduct keyTroubleshootingService Support Mode29ConfidentialEPSON WF-3720 SeriesSupply Status Sheet (total pages: 2 sheets)ItemDevice IDSerial NumberMAC AddressMemory CapacityHardware ConfigurationCard Reader StatusFirmwareMain FirmwareNetwork FirmwareQPITBlackCyanMagentaYellowMaintenance BoxPeriodic

Replacement

Parts

InformationOptional Cassette Informationmaintenance roller 1

to

maintenance roller 2Rear Paper FeedCassette 2Part NumberSerial NumberPart NumberSerial NumberPart NumberSerial NumberPart NumberSerial NumberPart NumberPart NumberNumber of Sheets LoadedNumber of Sheets LoadedFirmware VersionExplanationRevision CDevice ID (product name) is serial number of the product is

address of the product is ty of the memory inside the product

is tion condition of a device for user

authentication is n of the firmware is n of the main firmware is n of the NW firmware is n of the QPIT is Supply

UnitSupply

StatusModel number of each of the ink

cartridges is cturer's serial number of each of

the ink cartridges is model number of the Maintenance

Box is t value of the counter for the

periodic replacement part, the number of

replacements of the part, and the model

number of the part are version of the firmware of cassette 2 is

eshootingService Support Mode30ConfidentialEPSON WF-3720 SeriesUsage History Sheet (total pages: 2 sheets)ItemDevice IDSerial NumberMAC AddressHardware

ConfigurationMemory CapacityCard Reader StatusFirmwareMain FirmwareNetwork FirmwareQPITUsage HistoryFirst Time PrintingTotal Number of PagesTotal Number of B&W PagesTotal Number of Color PagesTotal Number of 2-Sided Printing PagesTotal Number of 1-Sided Printing PagesA3/LedgerA4/Letter

Size>(1-sided/2-sided,

B&W/Color)A5A6B4/LegalB5EnvelopeOthersB&W CopyColor CopyB&W FaxColor FaxB&W ScanNumber of printsColor ScanB&W Print from Computer or Mobile DeviceColor Print from Computer or Mobile DeviceB&W Print from Memory Device or

Other FunctionsColor Print from Memory Device or

Other FunctionsESC/P-R

Language>PCLPS and PDFOthersExplanationRevision CDevice ID (product name) is serial number of the product is

address of the product is ty of the memory inside the product

is tion condition of a device for user

authentication is n of the firmware is n of the main firmware is n of the NW firmware is n of the QPIT is date and time when the printer printed

for the first time is total number of printed pages is

total number of pages printed in

monochrome is total number of pages printed in color

is total number of printed 2-sided pages

is total number of printed one-sided

pages is of PagesThe total number of printed pages per

paper size is ed count per function (one-sided/2-sided, monochrome/color) is also

displayed for each paper total number of printed pages for each

of the purposes is version of each of the printer language

is eshootingService Support Mode31ConfidentialEPSON WF-3720 SeriesService Status Sheet (total pages: 16 sheets)ItemDevice IDSerial NumberMAC AddressMemory CapacityHardware ConfigurationCard Reader StatusFirmwareMain FirmwareNetwork FirmwareQPITSleep Timer

ExplanationRevision CDevice ID (product name) is serial number of the product is

address of the product is ty of the memory inside the

product is tion condition of a device for user

authentication is n of the firmware is n of the main firmware is

n of the NW firmware is n of the QPIT is r the sleep timer is enabled or not

is displayed. When enabled, the time

period before the product enters sleep

mode is also r the auto power off setting is

enabled or not is displayed. When

enabled, the time period before the printer

automatically turns off is also Ink Drying Time when duplex

printing is SettingsPower Off SettingsInk Drying TimeCassette 1

to Cassette

4MP trayPaper SizePaper TypePaper Size Auto DetectPaper SizePaper TypeTop Offset

Left Offset

Print SettingsUniversal

Print

SettingsTop Offset in BackLeft Offset in BackCheck Paper WidthSkip Blank PageIP AddressSubnet MaskDefault GatewayPrimary DNS ServerNetwork SettingsSecondary DNS ServerDNS Domain NameProxy Server SettingsProxy ServerProxy Server Port NumberPaper

Source

SettingsPaper CassettePaper size and type settings for each of the

paper sources are offset setting (-30 to 30) is r the setting is enabled or not is

r the setting is enabled or not is

network settings are eshootingService Support Mode32ConfidentialEPSON WF-3720 SeriesItemSubject (“Scan to Email” only)Color ModeFile Format (not provided for “Scan to Cloud”)Document Open Password (not provided for “Scan

to Cloud”)Permissions Password (not provided for “Scan to

Cloud”)PrintingEditingResolution (not provided for “Scan to Cloud”)2-SidedBinding PositionScan Area (not provided for “Scan to Cloud”)Remove Shadow (not provided for “Scan to Cloud”)SurroundScan

settings

Folder/FTP>

Device>ExplanationThe subject of email is on CThe color setting (Color or Mono) is

format setting is r the password setting is enabled

or not is r the password setting is enabled

or not is r printing scanned document is

permitted or not is r editing scanned document is

permitted or not is resolution setting is r the 2-sided scanning is enabled

or not is g position of documents (left/top/--- (in

case of one-side scanning)) is al document size setting is r the setting is enabled or not is

frame width setting (0 to 40 mm/---(in case of the shadow remove setting is

disabled)) is center width setting (0 to 40 mm/---(in case of the shadow remove setting is

disabled)) is r the setting is enabled or not is erasing setting (left edge/right edge/top edge/bottom edge/--- (in case of the

remove punch holes setting is disabled)) is

erasing amount (0 to 20 mm/--- (in

case of the remove punch holes setting is

disabled)) is document orientation setting (portrait

or landscape) is quality setting (Text/Text & Image/Photo) is setting of Mixed Size Original is density setting (-4 to 4) is displayed.------Whether the setting is enabled or not is r the setting is enabled or not is displayed.---The data compression ratio setting (Low/Middle/High) is maximum file size that can be

attached to an email is product key is displayed (“---” is

displayed when it is not set).CenterRemove Punch HolesErasing SettingErase AmountOrientation (original)Document TypeMixed Size OriginalDensityRemove BackgroundFile Name Prefix (not provided for “Scan to Cloud”)DateTimeContinuous Scan (ADF)Compression Ratio (not provided for “Scan to

Cloud”)Attached file Max Size (“Scan to Email” only)Epson Open Platform

InformationProduct keyTroubleshootingService Support Mode33ConfidentialEPSON WF-3720 SeriesItemFax FunctionLarge-Capacity

Paper Feed

UnitIntermediate UnitOptional

Cassette 1Optional

Cassette 2Optional

Cassette 3Serial NumberFW versionSerial NumberFW versionSerial NumberFW versionSerial NumberFW versionSerial NumberFW versionPart numberSerial NumberPart numberSerial NumberPart numberSerial NumberPart numberSerial NumberPart numberPart numbermaintenance roller 1 tomaintenance roller 4Number of Sheets LoadedNumber of ReplacementsNumber of Sheets LoadedNumber of ReplacementsNumber of Sheets LoadedNumber of ReplacementsPart numberNumber of Sheets LoadedBelt unitNumber of ReplacementsPart numberNumber of Sheets LoadedBelt cleanerNumber of ReplacementsPart numberADF feed

rollerHigh

capacity

input unitNumber of Sheets LoadedNumber of ReplacementsPart numberNumber of Sheets LoadedNumber of ReplacementsPart numberID of the print head is displayed.------ExplanationRevision CWhether the fax feature is enabled or not

is SettingsFirmware version of each of the option

cassettes are er FunctionBlackCyanInk CartridgesMagentaYellowMaintenance BoxModel number and manufacturer's serial

number of each of the ink cartridges is

model number of the Maintenance

Box is number of each of the feed rollers

is number of sheets fed by each of the

maintenance rollers is number of replacements (the number

of times the counter is reset) of each of the

paper feed rollers is

StatusRear Paper

FeedMist / VOC

Filter

Periodic replacement

partsPrint head serial IDHind head sensor degration

TroubleshootingService Support Mode34ConfidentialEPSON WF-3720 SeriesItemFirst Time PrintingTotal Number of Pages

Function>Total Number of B&W PagesTotal Number of Color PagesA3/Ledger

Paper Size>(1-sided/2-sided,

B&W/Color)A4/LetterA5A6B4/LegalB5EnvelopeOtherB&W Print from Computer or

Mobile DeviceColor Print from Computer or

Mobile DeviceB&W Copy

Usage>Color CopyB&W FaxColor FaxB&W Print from Memory Device or

Other FunctionsUsage HistoryColor Print from Memory Device or

Other FunctionsPlain papersLetterheadRecycledColorPreprintedHigh quality plain paper

Type>Thick-Paper 1Thick-Paper 2Thick-Paper 3MatteUltra GlossyPrem. GlossyPrem. semiglossGlossyEnvelopeOtherNumber of

Sheets

ScannedNumber of

Sheets

LoadedThe Cumulative number of paper

jamDocument Table (Number of pages)ADF (Number of pages)ADF (Number of Fed Sheets)Cassette 1 to Cassette 4, Rear Paper

Feed, Paper Feed SlotExplanationRevision CThe data and time the printer printed for

the first time are total number of pages printed by the

printer is total number of pages printed in

monochrome is total number of pages printed in color

is total number of printed pages per

paper size is displayed. Detailed count per

function (one-sided/2-sided,

monochrome/color) is also displayed for

each paper total number of printed pages for each

of the purposes is total number of pages printed on each

of the paper types is : Count in number of sheet.

Including paper number does not

meet with the other total number of times a paper jam

error occurs is total number of pages scanned on the

scanner glass or in the ADF is displayed.

The total number of document sheets fed

by the ADF is total number of printed pages per

paper source is eshootingService Support Mode35ConfidentialEPSON WF-3720 SeriesItemUser

Adjustment

Cleaning

HistoryNozzles

Clogging

StateCodeNameTimer of dayCodeTypeTimer of dayRankPrinter ErrorPaper Jam ErrorSetting Change HistoryFatal Error When PrintingExplanationRevision CAdjustment name and execution date and

time of last five adjustments executed by

the user are ng type and execution date and time

of last five cleaning operations are

displayed.A number that represents the level of

nozzle clogging is each of the errors, the following

information is displayed- Error Code- Sub Code- Date of Occurrence- Number of Pages- Internal Temperature- Internal Humidity- Paper PathFor each of the errors, the following

information is displayed- Error Code- Date of Occurrence- Number of Scan PagesFor each of the errors, the following

information is displayed- Error Code- Date of OccurrenceInk coverage of print jobs finished before

printing this status sheet is displayed

according to the rule below.L: less than 5%, M: 5% to 20%, H: more

than 20%Ink coverage of the last print job is

displayed according to the rule below.L: less than 20%, M: 5% to 50%, H: more

than 50%Error

HistoryScanner ErrorFatal Error When ScanningFax ErrorNetwork ErrorSystem ErrorOther ErrorPD1 LevelCoverageCoverage

RatioPD2 LevelPrinter ErrorScanner ErrorStatusFax ErrorNetwork ErrorOther Error---TroubleshootingService Support Mode36ConfidentialCHAPTER2DISASSEMBLY/REASSEMBLYConfidentialEPSON WF-3720 SeriesRevision C2.1 OverviewThis chapter describes procedures for disassembling the main parts/units of WF-3720 Series. Unless otherwise

specified, disassembled parts/units can be reassembled by reversing the disassembly procedure. See the cautions

or tips for disassembly/reassembly described in "2.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit (p54)".Read the " Safety Precautions (p3)" before disassembling and you have to remove units or parts that are not described in this chapter, see the exploded diagrams of SPI

(Service Parts Information).2.1.1 ToolsUse only specified tools to avoid damaging the (+) Phillips screwdriver #1(+) Phillips screwdriver #2Flathead screwdriverFlathead Precision screwdriver #1TweezersLongnose pliersAcetate TapeNote1:Some of the tools listed above are commercially available.2:EPSON provides the tools listed with EPSON part bilityOOOOOO---EPSON Part Code1080530---------------10039632.1.2 JigsNameThickness gauge (1.6 mm)Thickness gauge (1.24 mm)Teflon tape (thickness: 0.08 mm)Q’ty111EPSON Part CodeCommercially availableCommercially availableCommercially availableDisassembly/ReassemblyOverview38ConfidentialEPSON WF-3720 SeriesRevision C2.1.3 Locations of the Parts/UnitsThis section shows the locations of the main parts/units of WF-3720 parts/units which can not be seen in the following pictures are indicated in dotted lines

().Exterior partsFrontRight165243LeftRear798No.12345 Panel Assy (p49) Paper Cassette (p50) Stacker Assy (p53) NFC Board (p49)Name ADF Document Support (p50)No.6789 ADF Unit (p50) SCN Unit (p50) Duplex Unit (p50) Ink Eject Assy (p49)NameFigure or PartsDisassembly/ReassemblyOverview39ConfidentialEPSON WF-3720 SeriesPrinter mechanismRevision C615243No.123 Main Frame Assy (p52) Holder CSIC Assy (p49) PIS Board (p51)NameNo.456Name Paper Guide Front Assy (p52) Paper Guide Upper Assy. (p51) PE Sensor (p53)Figure r Mechanism: Front54132No.123 CR Unit (p52) Ink System Assy (p53) Printhead (p49)NameNo.45Name Holder Star Wheel Assy. (p51) Front Frame (p51)Figure r Mechanism: RightDisassembly/ReassemblyOverview40ConfidentialEPSON WF-3720 SeriesRevision C615432No.123 WiFi Board (p51) Speaker (p53) PF Scale (p52)NameNo.456 PF Encoder Sensor (p51) FAX Assy (p53) Main Board (p51)NameFigure r Mechanism: Left312No.13 Head FFC (p51) Holder Cam Assy (p52)NameNo.2 CR Motor (p51)NameFigure r Mechanism: RearDisassembly/ReassemblyOverview41ConfidentialEPSON WF-3720 SeriesRevision C2.1.4 Standard Operation Time for servicing the productThe following are the standard operation time for servicing the product. Those are based on the MTTR result

measured using a prototype of WF-3720 Series. Perform servicing referring to this operation standard underlined parts/units are supplied as After Service rd Operation TimeTime (mm:ss)Parts/UnitReplacement2:470:511:092:202:201:012:240:240:180:140:340:470:203:474:050:240:470:200:531:280:390:551:430:553:373:394:154:156:353:423:535:293:536:515:436:513:063:47Adjustment/inspection------------------21:27---------------------------------------------------------0:420:42---1:460:03---------------------Total2:470:511:092:202:201:0125:510:240:180:140:340:470:203:474:050:240:470:200:531:280:390:551:430:553:373:394:574:576:355:283:565:293:536:515:436:513:063:47Housing UpperHolder Board Assy CRCM Assy CSIC Connector (x4) Holder CSICCover Cable Head InnerPrintheadGuide I/CPickup Roller AssyHolder PickupPickup RollerPaper Stopper AssyCover-IFCover-ink-EjectInk Eject AssyStacker Support Front AssyCover ADF AssyADF Document SupportFrame Upper ADF Assy ADF PAD Assy. & SpringDocument PadCover Front ADFFrame Front ADF AssyCover Rear ADFADF MechADF/SCN Unit ADF Unit SCN UnitGround Plate PSPower Supply Assy. Housing Panel Lower Holder Tilt Left Panel Board NFC Board Housing Panel UpperFrame RightSCN Hinge AssyDisassembly/ReassemblyOverview42ConfidentialEPSON WF-3720 SeriesTable rd Operation TimeTime (mm:ss)Parts/UnitReplacement3:543:545:247:238:1111:1413:4014:0814:0816:0216:1616:3516:4217:0117:5819:0617:197:328:089:178:148:499:319:5010:2510:3610:368:317:549:029:028:287:588:188:439:047:357:237:3613:3210:5610:19Revision CAdjustment/inspection---------19:19---------21:01---18:25---------------------------0:23---5:203:58------------------0:430:25------------------------0:22---0:13Total3:543:545:2429:258:1111:1413:4037:5214:0837:1016:1616:3516:4217:0117:5819:0617:197:328:0812:238:1416:5216:129:5010:2510:3610:368:317:5412:2812:108:287:588:188:439:047:357:237:3613:5410:5610:32 Rack Hinge Box Gear Hinge Cassette SensorPrinter Mechanism CR Scale Main Board Assy. Shield Plate Upper Main Board Frame Left Main Frame Assy Cap Detector PW PW Sensor Main Frame Timing Belt CR Encoder CR Unit Paper Guide Front Assy WiFi Board Holder Driven Assy (w/Spring) CR Motor Ground Plate Front Frame Holder Star Wheel Assy. Reinforcement Plate Holder Star Wheel PIS Sensor PIS FFC Holder Star Wheel PF Encoder Sensor Paper Guide Upper Spring (x3) Paper Guide Upper Assy. Holder Lever PE Assy. Head FFC Holder Cam Assy Spring Slider Cover ASF Drive Slider-Trans & Gear PF ScaleFrame Base Assy. Stacker Assy Ink System Assy Porous Pad Cap Lower PE SensorDisassembly/ReassemblyOverview43ConfidentialEPSON WF-3720 SeriesTable rd Operation TimeTime (mm:ss)Parts/UnitReplacement10:148:279:439:539:538:107:387:378:01Revision CAdjustment/inspection0:03------------------------Total10:178:279:439:539:538:107:387:378:01 Porous Pad Paper Guide Lower FAX Assy Shield Plate Fax Lower FAX Board Shield Plate Fax Upper Host USB Assy. Speaker Pickup Gear Shaft Drive PickupDisassembly/ReassemblyOverview44ConfidentialEPSON WF-3720 SeriesRevision C2.2 Common cautions when disassembling/reassembling the ProductThis section describes common cautions when disassembling/reassembling the disassembling/reassembling the printer including this product, be sure to read " Safety Precautions (p3)"

and this en

handling

handling new parts for replacement, take care not to contaminate

or damage disassembling/reassembling the parts, take care not to damage

the FFCs/cables/Ink tube if there is a possibility of coming into contact

with reassembling the product, take care not to let components of the

unit come installing parts, take care not to damage them when securing them

by tightening not lubricate any part other than those specified. If grease is applied on

such a part, wipe it off m visually that there are no scratches, dirt, and reassembling, confirm that there are no abnormal noises and they

work /

reassemblingWhen

applying

greaseExternal

partsMoving

care not to broke m that it is installed properly onto the transmissive sections of

the pinion gear/driven SensorsTake care not to damage care not to touch the detector for the encoder Sensor used with a circular scale, the photo sensor

section should be set over the encoded area of the circular care not to get injured by the sharp ends of the board terminal on

the back of the circuit boards when handling the sensors or the

peripheral care not to touch the encoded l it with the black triangular section down. (CR Scale only)Wipe off alcohol before installing. (CR Scale only)Confirm that they do not touch the photo sensors after installation.2.--- ink

care not to stain your hands with the waste ink soaked in the ink

pads. If ink comes into contact with your hands, wash it off with water

care not to stain the printer's parts with the waste ink soaked in the

ink pads. If ink comes into contact with the parts, wash it off.

(Especially, pay attention to Paper Guide Front/Lower Porous Pad)embly/ReassemblyCommon cautions when disassembling/reassembling the Product45ConfidentialEPSON WF-3720 sure to insert them to their connectors on the boards as far as they

will go without any loose connection such as a half-way or slant

them along their routing the double-sided tape that secures the FFCs is not strong enough to

secure them, make sure to replace the tape and secure the FFCs installing gears, pay attention to the following:•The gear section should not be damaged.•No foreign material is attached.•No grease is attached on any parts other than those not touch rollers for paper feeding when handling /IllustrationRevision C---Gears---PF rollersOne Time

partsADF/Scanner

UnitAfter removing One Time parts specified in this manual, do not reuse

them, but be sure to replace them with new ADF/SCN disassembly/reassembly, if you let go of the ADF/SCN Unit

with the hinge released, the unit may fall backwards, causing breakage,

therefore after removing the ADF/SCN Unit Hinge, take care to ensure the

unit is supported Time icon:

Ink care not to stain your hands with you connect the ink tube to another part, insert the ink tube up to

the root of the joint to prevent ink leakage and secure the tube with the

tube it's hard to insert the ink tube to the joint, apply CR02 to the inserting

part of the ink care not to stain or damage replacing the Housing Upper, transfer the MAC address label to

the new Left Frame.2.---MAC

Address

LabelLeft FrameDisassembly/ReassemblyCommon cautions when disassembling/reassembling the Product46ConfidentialEPSON WF-3720 SeriesRevision C2.3 Disassembly/Reassembly Procedures2.3.1 Functional differences between models and component partsIn "2.3.2 Disassembly Flowchart (p48)", the procedures are indicated on the premise that some parts/units are

removed in advance. Make sure to remove the following parts/units before starting disassembly.Cassette te ng the Cassette AssyAuto Duplex UnitAuto Duplex UnitFigure ng the Auto Duplex UnitDisassembly/ReassemblyDisassembly/Reassembly Procedures47ConfidentialEPSON WF-3720 SeriesRevision C2.3.2 Disassembly FlowchartThis section describes procedures for disassembling the parts/units in a flowchart format. For some parts/units,

detailed procedures or precautions are provided (accordingly indicated by icons and cell's color). Refer to the

explanations in the example chart below and perform an appropriate disassembling and assembling procedure.

(See "2.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit (p54)".)For routing cables, see "2.5 Routing FFCs/cables (p58)".The example below shows how to see the charts on the following name enclosed in gray

indicate a part/unit that

must be removed on the

way to the target necessary

procedures before

removing the following

parts.* Paper Guide

Upper Assy (p29)CR Timing BeltFFC/Cable * 1Printer

Mechanism---1S2Main Frame AssyWhite letters indicate a

part/unit supplied as

an the screw types

and the specified

torque in the “Screw

type/torque list”.Black letters indicate a

part/unit not supplied as

an ASP.--- (p 21) (p 27)4 (p 43) (p 22)

Reference pageNote"*":The boxes with only part names indicates the removal of such parts. If the names of FFCs or cables are

shown, disconnect the FFCs or cables from their rts/unit nameWhite-letterBlack-letterDescriptionPart/unit supplied as an ASPPart/unit not supplied as an ASPIndicates a practice or condition that could result in

injury or loss of life if not strictly tes a practice or condition that could result in

damage to, or destruction of equipment if not strictly

tes the parts that are inevitably broken in the

disassembling procedure, and should be replaced with a

new one for tes necessary check items in the disassembling/assembling nce------Indicates the reference

page in blue-letterIndicates the reference

page in blue-letter---Indicates the reference

page in blue-letterIndicates the reference

page in blue-letterIndicates the reference

page in blue-letterIndicates the reference

page in blue-letterChapter 3 " Adjustment

(p61)"Chapter 4 " Maintenance

(p80)"------IconIndicates supplementary explanation for disassembly is

tes particular tasks to keep quality of the units are

tes particular routing of cables is tes particular adjustment(s) is/are tes lubrication is tes the number of screws securing the parts/tes the points secured with other than a screw

such as a hook, rib, dowel or the embly/ReassemblyDisassembly/Reassembly Procedures48ConfidentialEPSON WF-3720 SeriesRevision C2.3.3.1Disassembly/Reassembly Flowchart

START1SCN Hinge

Screw (x1)CR Lock ReleaseGuide I/C---Housing Upper9S19S20(p 50)Pickup Roller

Assy---1---Holder Pickup---1---Paper Stopper

Assy2S1Cover-IF1S19Cover ADF Assy---2---Cover-ink-Eject1S19Holder CSIC

Assy---2------2---11 (p 80)------3 (p 54)CRCM Assy---Pickup Lever---------Pickup Roller---1---Ink Eject AssyPanel FFC x1Panel Board7Panel AssyS1S16S17S11---Cover Cable

Head Inner---2------2------3CSIC Connector

(x4)---S5------ (p 61) (p 58)

Housing Panel

UpperHousing Panel

Lower---5S1Printhead3S42Holder Tilt Left------------3 (p 61) (p 54)

Holder CSIC---------15---Screw type/torque listSymbolScrew TypeC.B.P-TITE SCREW,3X10,F/ZN-3CC.B.S-TITE SCREW,3X6,F/ZN-3CC.B.S-TITE SCREW,2X8,F/ZN-3CC.B.P-TITE SCREW,2.5X8,F/ZN-3CC.B.P-TITE SCREW,3X8,F/ZN-3CC.B.P-TITE SCREW,2.5X6,F/ZN-3CC.B.P-TITE (S-P1) SCREW,3X12,F/ZN-3CC.B.P-TITE SCREW,2X16,F/ZN-3CC.B.P-TITE SCREW,2X10,F/,3X4,F/,3X8,F/ZN-3CC.B.P-TITE SCREW,2X8,F/ZN-3CC.B.S-TITE SCREW,3X6,F/ZN-3CC.B.P-TITE SCREW,3X16,F/ZN-3CC.B.S-TITE SCREW,3X6,F/ZN-3CC.B.P-TITE SCREW,2.5X8,F/ZN-3CC.B.P-TITE.P2 SCREW,2.5X8,F/,3X8,F/ZN-3CC.B.P-TITE SCREW,3X10,F/,3X8,F/ZB-3CTorque6±1 kgf·cm6±1 kgf·cm4±1 kgf·cm4±0.5 kgf·cm6±1 kgf·cm4±0.5 kgf·cm6±1 kgf·cm2±0.5 kgf·cm2±0.5 kgf·cm4±1 kgf·cm8±1 kgf·cm3±0.5 kgf·cm8±1 kgf·cm13±1 kgf·cm4±1 kgf·cm5±0.5 kgf·cm6.5±0.5 kgf·cm8±1 kgf·cm6±1 kgf·cm6±1 kgf·cmNFC Board---S1---Power supply cable x1---S2S33S4S5S6Frame Right1S1---Power Supply

Unit------S7S8S9S10S11---SCN Hinge Assy3SCN FFC x2ADF PE Sensor Cable

S1 (p 61) (p 58)

S12S13S14---Rack Hinge

---1Box Gear Hinge

Assy---1--- (p 54)S15S16S17S18S192(p 50)---S20Flowchart embly/Reassembly Flowchart (1)Disassembly/Reassembly49Confidential