EPSON ET-4750, ET-4760, L6190, ST-4000, ET-3750 Service Manual

Service Manual

Color Inkjet Printer

EPSON

ET-4750/ET-4760/L6190/ST-4000 series

ET-3750/ET-3760/L6170/ST-3000 series

ET-3700/ET-3710/L6160series

ET-2750/ET-2760/L4160/ST-2000 series

ET-2700/L4150series

Confidential

SEMF17-003

Notice

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 thereof.

EPSON is a registered trademark of SEIKO EPSON CORPORATION.

Notice:	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 marks.

Copyright © 2018 SEIKO EPSON CORPORATION.

P CS QualityAssurance Department

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Safety Precautions

All safety procedures described here shall be strictly adhered to by all parties servicing and maintaining this product.

DANGER

Strictly observe the following cautions. Failure to comply could result in serious bodily injury or loss of life.

1.Always disconnect the product from the power source and peripheral devices when servicing the product or performing maintenance.

2.When 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 shock.

WARNING

Strictly observe the following cautions. Failure to comply may lead to personal injury or loss of life.

1.When using compressed air products; such as air duster, for cleaning during repair and maintenance, the use of such products containing flammable gas is prohibited.

PRECAUTIONS

Strictly observe the following cautions. Failure to comply may lead to personal injury or damage of the product.

1.Repairs on Epson product should be performed only by an Epson certified repair technician.

2.No work should be performed on this product by persons unfamiliar with basic safety knowledge required for electrician.

3.The 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 voltage.

4.Replace 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 warranty.

5.The 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 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/ reassembly.

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6.To 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 insertion.

7.In order to protect sensitive microprocessors and circuitry, use static discharge equipment, such as anti-static wrist straps, when accessing internal components.

8.Do 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 charge.

9.Never 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 immediately.

10.When disassembling or assembling this product, make sure to wear gloves to avoid injuries from metal parts with sharp edges.

11.Use only recommended tools for disassembling, assembling or adjusting the printer.

12.Observe the specified torque when tightening screws.

13.Be extremely careful not to scratch or contaminate the following parts.

Nozzle plate of the printhead

CR Scale

PF Scale

Coated surface of the PF Roller

Gears

Rollers

LCD

Scanner Sensor

Exterior parts

14.Never 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 function.

15.Apply the specified amount of grease described in this manual.

16.Make the specified adjustments when you disassemble the printer.

17.When cleaning this product, follow the procedure described in this manual.

18.When transporting this product after filling the ink in the printhead, pack the printer without removing the adapters in order to prevent the printhead from drying out.

19.Make sure to install antivirus software in the computers used for the service support activities.

20.Keep the virus pattern file of antivirus software up-to-date.

21.When 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 secured.

22.Unless 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 product.

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About This Manual

This manual, consists of the following chapters, is intended for repair service personnel and includes information necessary for properly performing maintenance and servicing the product.

CHAPTER 1. OPERATING PRINCIPLES

Describes the electrical and mechanical basic operating principles of the product.

CHAPTER 2. TROUBLESHOOTING

Describes the step-by-step procedures for the troubleshooting.

CHAPTER 3. DISASSEMBLY/ASSEMBLY

Describes the disassembly/reassembly procedures for main parts/units of the product, and provides the standard operation time for servicing the product.

CHAPTER 4. ADJUSTMENT

Describes the required adjustments for servicing the product.

CHAPTER 5. MAINTENANCE

Describes maintenance items and procedures for servicing the product.

CHAPTER 6. APPENDIX

Provides the following additional information for reference:

•Connector Diagram

•Protection for Transportation

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Symbols Used in this Manual

Various 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 instructions.

Indicates an operating or maintenance procedure, practice or condition that, if not strictly observed, could result in injury or loss of life.

Indicates an operating or maintenance procedure, practice, or condition that, if not strictly observed, could result in damage to, or destruction of, equipment.

May 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 action.

For Chapter 3 “Disassembly/Reassembly”, symbols other than indicated above are used to show additional information for disassembly/reassembly. For the details on those symbols, see "3.3 Disassembly/Reassembly Procedures (p94)".

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Revision Status

	Revision	Date of Issue	Description
	A	Aug. 31, 2017	First release
			Revised
			Chapter 3
			Made change in "3.1 Overview (p76)"
			• Made change in "3.1.2 Jigs (p76)"
			• Made change in "3.1.4 Standard Operation Time for Servicing the Product (p80)"
			Made change in "3.3 Disassembly/Reassembly Procedures (p94)"
			• Made change in "3.3.3 Disassembly Flowchart (p96)"
	B	Feb. 26, 2018	• Made change in "3.3.4 Repairing Major Components Disassembly/Assembly Procedure (p112)"
			Made change in "3.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit (p141)"
			Made change in "3.5 Routing FFCs/cables (p144)"
			Chapter 4
			Made change in "4.3 Mechanism Adjustment / Check (p165)"
			• Made change in "4.3.1 Checking the Platen Gap (p165)"
			Chapter 6
			"6.2 Head Fuse (p180)" has been added.
	C	May. 11, 2018	Display Bugs fixes.
			Hyper links have been fixed.
			Revised
			Add models (ST-2000, ST-3000, ST-4000)
			□ Chapter3
	D	Sep. 19, 2018	■Made change in "3.1.1 Tools (p76)"
			■Made change in "3.1.4 Standard Operation Time for Servicing the Product (p80)"
			The Fax outringer box has been deleted.
			■Made change in "3.3.2 Functional differences between models and component parts (p95)"
			■Made change in "3.3.3.1 Disassembly/Reassembly Flowchart (ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-
			3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series) (p97)"
	E	Mar. 25, 2019	Revised
			Add models (ET-4760 series, ET-3760 series, ET-3710 series, ET-2760 series)

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		Revised
		□ Chapter3
F	Apr. 16, 2019	■Made change in "3.3.4.7 Main Board (p128)"
		Caution about Heat Conduction sheet has been added.
		■Made change in "3.5 Routing FFCs/cables (p144)"
		" Holder Star Wheel Grounding Cable (ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST-3000
		series/ET-3700/ET-3710/L6160 series) (p148)"has been added.
		Revised
		□ Chapter2
		■Made change in "2.1.1.3 Workflow for Errors when Printing Starts (p45)"
		Subscription Errors have been added.
G	Jan. 28, 2020	□ Chapter3
		■For ET-2700/L4150 series, Descriptions of Paper Set Detector Sensor Board have been deleted.
		□ Chapter4
		■Made change in "4.1 Required Adjustments (p150)"
		Caution of subscription models has been added.

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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

Revision G

Contents

Chapter 1 Operating Principles
1.1 Printer Mechanism Overview .............................................................................	12
1.1.1 Print Head ..................................................................................................	12
1.1.2 Carriage (CR) Mechanism .........................................................................	14
1.1.3 Paper Loading/Feed Mechanism ...............................................................	15
1.1.4 Ink System Mechanism ..............................................................................	17
1.1.5 List of Motor and Sensor ...........................................................................	18
1.2 Scanner/ADF Overview .....................................................................................	20
1.2.1 Scanner Mechanism ...................................................................................	20
1.2.2 ADF Mechanism (ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-
3760/L6170/ST-3000 series only) ............................................................	20
1.3 Paper Loading/Feed Mechanism ........................................................................	22
1.3.1 Overview ....................................................................................................	22
1.3.1.1 Paper Loading Method .......................................................................	22
1.3.1.2 Paper Feed Path ..................................................................................	24
1.3.2 Operation Principle ....................................................................................	26
1.3.2.1 Drive Path ...........................................................................................	26
1.4 Ink System Mechanism ......................................................................................	33
1.4.1 Overview ....................................................................................................	33
1.4.1.1 Mechanical Configuration ..................................................................	33
1.4.1.2 Cleaning ..............................................................................................	34
1.4.1.3 Controlling Waste Ink ........................................................................	34
1.4.2 Operating Principles ..................................................................................	35
1.4.2.1 Drive Path ...........................................................................................	35
1.4.2.2 Operation of Each Mechanism ...........................................................	36
Chapter 2 Troubleshooting
2.1 Troubleshooting ..................................................................................................	40
2.1.1 Troubleshooting Workflow .......................................................................	40
2.1.1.1 Workflow when the Power is ON (Printer) ........................................	41
2.1.1.2 Workflow for Scanner Errors when the Power is ON ........................	44
2.1.1.3 Workflow for Errors when Printing Starts .........................................	45

2.2 Power-On Sequence ...........................................................................................	47
2.3 Fatal Error Code List ..........................................................................................	48
2.3.1 Displaying the Fatal Error Code ................................................................	48
2.3.2 Fatal Error Code ........................................................................................	48
2.3.2.1 Scanner ...............................................................................................	49
2.3.2.2 Printer (CR) ........................................................................................	55
2.3.2.3 Printer (PF) .........................................................................................	58
2.3.2.4 Printer (PW/PE Sensor) ......................................................................	60
2.3.2.5 Printer (Power Supply) .......................................................................	60
2.3.2.6 Printer (Head/CSIC) ...........................................................................	61
2.3.2.7 Printer (Others) ...................................................................................	62
2.3.2.8 System Error .......................................................................................	62
2.4 Service Support Mode ........................................................................................	63
2.4.1 Touch Panel 2.4 inch model ......................................................................	63
2.4.2 LCD Model ................................................................................................	64
2.4.3 Status Sheet Information ...........................................................................	66
Chapter 3 Disassembly/Assembly
3.1 Overview ............................................................................................................	76
3.1.1 Tools ..........................................................................................................	76
3.1.2 Jigs .............................................................................................................	76
3.1.3 Locations of the Parts/Units ......................................................................	77
3.1.4 Standard Operation Time for Servicing the Product .................................	80
3.1.5 Checks and Precautions before Disassembling .........................................	86
3.1.5.1 Factors which Affect the Print Quality ..............................................	86
3.1.5.2 Minimizing Ink Leakage during Disassembly for Your Safety .........	88
3.1.5.3 Ink Discharging Procedure .................................................................	91
3.2 Common Cautions on Disassembly/Reassembly ...............................................	92
3.3 Disassembly/Reassembly Procedures ................................................................	94
3.3.1 Parts/Components Need to be Removed Before Disassembly/Reassembly 94
3.3.2 Functional differences between models and component parts ......	95
3.3.3 Disassembly Flowchart ..............................................................................	96
3.3.3.1 Disassembly/Reassembly Flowchart (ET-4750/ET-4760/L6190/ST-4000
	9

Confidential

EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

Revision G

series/ET-3750/ET-3760/L6170/ST-3000 series/ET-3700/ET-3710/
L6160 series) ......................................................................................	97
3.3.3.2 Disassembly/Reassembly Flowchart (ET-2750/ET-2760/L4160/ST-2000
series) ...............................................................................................	102
3.3.3.3 Disassembly/Reassembly Flowchart (ET-2700/L4150 series) ........	107
3.3.4 Repairing Major Components Disassembly/Assembly Procedure ..........	112
3.3.4.1 Maintenance Box/Porous Pad Assy .................................................	112
3.3.4.2 Exterior Parts ....................................................................................	113
3.3.4.3 ADF/SCN Unit or SCN Unit ............................................................	121
3.3.4.4 Paper Guide Front Assy ...................................................................	123
3.3.4.5 Paper Guide Lower Porous Pad ........................................................	124
3.3.4.6 Print Head .........................................................................................	125
3.3.4.7 Main Board .......................................................................................	128
3.3.4.8 Ink Tank ...........................................................................................	130
3.3.4.9 Paper Guide Upper Left ...................................................................	133
3.3.4.10 Paper Guide Upper Right ...............................................................	137
3.3.4.11 PF Roller .........................................................................................	138
3.3.4.12 Housing Rear Assy .........................................................................	140
3.4 Detailed Disassembly/Reassembly Procedure for each Part/Unit ....................	141
3.5 Routing FFCs/cables ........................................................................................	144

Chapter 4 Adjustment

4.1	Required Adjustments ......................................................................................	150
4.2	Adjustment Program .........................................................................................	154
	4.2.1 Operating Environment ...........................................................................	154
	4.2.2 Adjustment and Inspection List ...............................................................	154
	4.2.3 Details of the Adjustment Program .........................................................	159
4.3	Mechanism Adjustment / Check ......................................................................	165
	4.3.1 Checking the Platen Gap .........................................................................	165
	4.3.1.1 Preparation ........................................................................................	165
	4.3.1.2 Confirmation procedure ...................................................................	167
	4.3.2 Touch Panel Adjustment (ET-4750/ET-4760/L6190/ST-4000 series only) ..
	168

Chapter 5 Maintenance

5.1 Cleaning ............................................................................................................	171
5.1.1 Cleaning the CR Unit (ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/
ET-3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series) ........	171

5.1.2 Cleaning the nozzle plate section of the Print Head
(ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series) ......	172
5.1.3 Cleaning the Exterior Parts/inside of the printer .....................................	173
5.2 Lubrication .......................................................................................................	173
5.2.1 Lubrication Points and Instructions .........................................................	174

Chapter 6 Appendix

6.1	Connector Diagram ..........................................................................................	179
6.2	Head Fuse .........................................................................................................	180
6.3	Protection for Transportation ...........................................................................	181
	6.3.1 Securing the CR Unit ...............................................................................	181
	6.3.2 Securing the ADF/SCN Unit (ET-4750/ET-4760/L6190/ST-4000 series/ET-
	3750/ET-3760/L6170/ST-3000 series only) ...........................................	181
	6.3.3 Securing the SCN Unit (ET-3700/ET-3710/L6160 series/ET-2750/ET-2760/
	L4160/ST-2000 series/ET-2700/L4150 series) ......................................	182
	6.3.4 Securing the Panel Unit ...........................................................................	182

6.3.5 Securing the Stacker (ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-

3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series only) ......

183

6.3.6 Securing the Stacker (ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/

L4150 series only) ..................................................................................

183

6.3.7 Securing the Duplex Unit (ET-4750/ET-4760/L6190/ST-4000 series/ET- 3750/ET-3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series only) 184

6.3.8 Securing the Duplex Unit (ET-2750/ET-2760/L4160/ST-2000 series/ only) 184

6.3.9 Securing the Paper Support (ET-2750/ET-2760/L4160/ST-2000 series/ET-

2700/L4150 series only) .........................................................................

185

10

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CH1APTER

OPERATINGPRINCIPLES

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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

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1.1 Printer Mechanism Overview

This chapter describes overview of each mechanism inside the printer.

1.1.1 Print Head

μTFP1S head (p 12) is used for ET-4750/ET-4760/L6190/ST-4000 series/ET- 3750/ET-3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series.

F2 head (p 13) is used for ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/ L4150 series.

ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST- 3000 series/ET-3700/ET-3710/L6160 series

Table 1-1. Nozzle Configuration

Color	Four colors: black (Bk), cyan (C), magenta (M), yellow (Y)
Number of nozzles	784 nozzles:
	400 nozzles for Bk, and 128 nozzles for each of Y, M, and C
Nozzle pitch	300 dpi
		Cover Head		Nozzle plate

Figure 1-1. μTFP1S Print Head appearance

Cover Head

Paper feed direction

		1.016 mm
		24/600 inch	Nozzle plate
	A#400	B#400
		B#399
	A#399
		B#398	Cyan
	A#398
		B#273
		B#272	Not used
		B#265
		B#264	Magenta
	Black	B#137
		B#136	Not used
		B#129
		B#128

0.042 mm		Yellow
		B#3
1/600 inch	A#3
		B#2
	A#2		0.085 mm
		B#1
	A#1		1/300 inch
	Column A	Column B

Carriage movement direction

Column Color

ABk

B #1 - #128	Y
B #137 - #264	M
B #273 - #400	C

Figure 1-2. Nozzle layout (seen from the rear side)

Operating Principles	Printer Mechanism Overview	12
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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series							Revision G
ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series
	Table 1-2.	Nozzle Configuration		Nozzle plate	5.9266 mm
Color	Four colors: black (Bk), cyan (C), magenta (M), yellow (Y)				42/180 inch
Number of nozzles	357 nozzles:					B#180
	180 nozzles for Bk, 59 nozzles for each Y, M, and C.				A#180
						B#179
					A#179
Nozzle pitch	180 dpi					B#178	Cyan
					A#178
						B#123
	Cover Head	Nozzle plate	direction			B#122
						B#121	Not used
			feed	Black		B#63	Magenta
						B#62
			Paper
						B#61	Not used
				0.071 mm			Yellow
						B#3
				1/360 inch	A#3
						B#2	Not used
					A#2
						B#1
					A#1
						Column B
					Column A
					Carriage movement direction

Figure 1-3. F2 Print Head appearance

Column Color

A	Bk
B #1 - #60	Y
B #62 - #120	M
B #122 - #180	C

Figure 1-4. Nozzle layout (seen from the rear side)

Operating Principles	Printer Mechanism Overview	13
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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

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1.1.2 Carriage (CR) Mechanism

The major components of the carriage (CR) mechanism are the CR Unit, CR Encoder Sensor, CR Scale, CR Motor, and CR Timing Belt. The CR mechanism is a key mechanism to ensure stable print quality because printing is performed by moving the CR Unit from side to side.

As shown on the right, Main Frame is holding the upper side and the lower side of the CR Unit. The CR Unit is attached to the CR Timing Belt that is moved by the CR Motor so that the assy can move from side to side to print. The position and speed of the CR Unit are always monitored by the CR Encoder Sensor and the CR Scale, and the CR Motor is controlled in accordance with the information acquired by the CR Encoder Sensor.

Section view

CR Unit

CR Motor	Main Frame
(Backside of the Main Frame)
Main Frame	CR Encoder Sensor

CR Scale

CR Unit

CR Timing Belt

Figure 1-5. Carriage (CR) mechanism

Operating Principles

Printer Mechanism Overview

14

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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

Revision G

1.1.3 Paper Loading/Feed Mechanism

Paper loading mechanism differs between ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series and ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series. ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series employ the front paper loading, and ET- 2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series employ the rear paper loading. The both paper loading mechanisms are driven by the PF Motor, and the motor is also used for driving the paper feeding mechanism.*1

The printer is also equipped with a paper feeding mechanism for auto duplexing as well as other existing products. The mechanism flips paper after printing on the front side is finished, and feeds the paper to print on the back side.

ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST- 3000 series/ET-3700/ET-3710/L6160 series

A sheet of paper is fed inside the printer from the Paper Cassette by the Pick up

Roller Assy.

Because the Pick up Roller Assy needs to be stopped each after it feeds a sheet of paper, it is necessary to control the transmission of a drive force to the assy. The control is achieved by the Slider Trans and the Holder Cam Assy. When the Slider Trans is moved by the CR Unit, the state of engagement between the transmission gear on the Trans Slider and the Pick up Roller driving gear changes, which enables switching between transmitting the PF Motor driving force to the Pick up Roller Assy and not transmitting it.

Even after the CR Unit is detached from the Slider Trans for printing, position of the Slider Trans is kept by the Holder Cam Assy.

The paper fed by the Pick up Roller Assy is conveyed by the intermediate roller, PF Roller, and EJ Roller which are included in the paper feeding mechanism.

*1. See "1.3 Paper Loading/Feed Mechanism" (p 22) for more details.

Holder Cam Assy

Intermediate roller (inside the Duplex Unit)

Slider Trans

PF Motor

EJ Roller

PF Roller

Cassette

Pick up Roller Assy

Figure 1-6. Paper loading/feed mechanism (1)

Operating Principles

Printer Mechanism Overview

15

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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

Revision G

ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series

Paper is fed inside the printer from the ASF Rear by the LD Roller.

The ASF Rear is equipped with a Hopper, Paper Back Lever, Change Lever, LD Roller, and clutch. The Change Lever and the clutch work for transmitting a driving force from the PF Motor to the LD Roller and for not transmitting it.

The Hopper and the Paper Back Lever driven by the cam on the LD Roller Shaft prevent multi-feed and ensure accurate paper feeding.

Paper fed by the ASF Rear is conveyed by the PF Roller and the EJ Roller which are included in the paper feeding mechanism.

Unlike the front paper loading, intermediate roller is used only when flipping paper for duplex printing.

HopperCam

Clutch

Intermediate roller

(inside the Duplex Unit)

Change Lever

PF Motor

EJ Roller

PF Roller

Paper Back Lever	LD Roller

Figure 1-7. Paper loading/feed mechanism (2)

Operating Principles

Printer Mechanism Overview

16

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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

Revision G

1.1.4 Ink System Mechanism

The major components of the ink system mechanism*1 are a cap, pump unit,

and waste ink tube. Maintenance Box/

Porous Pad Assy

The ink system mechanism employs the slide type capping. When the CR Unit returns to its capping position (home position), the Print Head is capped. The pump mechanism, wiper mechanism, and the CR Lock mechanism are driven by the PF Motor to clean the Print Head.

Waste ink sucked when cleaning the Print Head is collected in the Maintenance

Box/Porous Pad Assy through the pump mechanism.

User replaceable Maintenance Box is installed to ET-4750/ET-4760/L6190/ ST-4000 series/ET-3750/ET-3760/L6170/ST-3000 series/ET-3700/ET-3710/ L6160 series. A CSIC mounted on the Maintenance Box keeps track of how much waste ink has been collected.

On the other hand, the Porous Pad that cannot be replaced by user is installed to ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series. The EEPROM on the Main Board keeps track of how much waste ink has been

collected.

Ink system mechanism

Figure 1-8. Ink system mechanism

*1. See "1.4 Ink System Mechanism" (p 33) for more details.

Operating Principles

Printer Mechanism Overview

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Revision G

1.1.5 List of Motor and Sensor

This section describes the types and positions of the motors and sensors.

ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST- 3000 series/ET-3700/ET-3710/L6160 series

	Table 1-3. Motor and Sensor List					A
(ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST-3000					5
	series/ET-3700/ET-3710/L6160 series)					1
					7
Mechanism name	Motor/sensor name	Motor/sensor type	No.
					8
Carriage	CR Motor	DC Motor	A			2
mechanism
	CR Encoder	Transmission-type photo	1
		interrupter
	PW Sensor	Reflection-type photo interrupter	2
Paper loading/feed	PF Motor	DC Motor	B
mechanism
	PF Encoder	Transmission-type photo	3
		interrupter
	Cassette Sensor	Mechanical contact	4
	PE Sensor	Reflection-type photo interrupter	5
Others	Ink Cover Open Sensor	Mechanical contact	6
Scanner	SCN Motor	DC Motor	C
	SCN Motor Encoder	Transmission-type photo	7	4		6
		interrupter
	ADF PE Sensor	Transmission-type photo	8
		interrupter			3
						C
					B

Figure 1-9. List of motor and sensor (ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST- 3000 series/ET-3700/ET-3710/L6160 series)

Operating Principles	Printer Mechanism Overview	18
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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

Revision G

ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series

Table 1-4. Motor and Sensor List (ET-2750/ET-2760/L4160/ST-2000 series/ET2700/L4150 series)

	Mechanism name	Motor/sensor name	Motor/sensor type	No.
	Carriage	CR Motor	DC Motor	A
	mechanism
		CR Encoder	Transmission-type photo	1
			interrupter
		PW Sensor	Reflection-type photo interrupter	2
	Paper loading/feed	PF Motor	DC Motor	B
	mechanism
		PF Encoder	Transmission-type photo	3
			interrupter
		ASF Rear Paper existence	Mechanical contact	4
		Sensor
		PE Sensor	Reflection-type photo interrupter	5
	Scanner	SCN Motor	DC Motor	C
		SCN Motor Encoder	Transmission-type photo	6
			interrupter

4A

5	1

6

3

2

BC

Figure 1-10. List of motor and sensor (ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series)

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Revision G

1.2 Scanner/ADF Overview

1.2.1 Scanner Mechanism

The scanner mechanism consists of a CIS sensor that scans documents and the SCN motor that drives the scanner carriage. The CIS sensor and the SCN motor are integrated as the scanner carriage, and it moves along the rail on the scanner housing to scan documents.

Scanner Unit

CIS Sensor

SCN Motor

Figure 1-11. Scanner mechanism

1.2.2 ADF Mechanism (ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST-3000 series only)

The PF Roller, EJ Roller, and Pick up Roller of the ADF mechanism are driven by the SCN Motor. The drive force of the motor is transmitted through the transmission gear. The ADF mechanism does not support auto duplex scanning.

EJ Roller

ADF PE Sensor

ADF Document

Lever

PF Roller

Pick up Roller

SCN Motor

ADF Unit

Pick up Roller

EJ Roller

Transmission

gear

Figure 1-12. ADF mechanism

Operating Principles

Scanner/ADF Overview

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Revision G

When scanning document, the document is fed inside the ADF as shown below.

Pick up Roller

Separation roller

ADF Document Lever

EJ Roller

Presence or absence of document on the ADF is detected by the ADF Document Lever and the scanner CIS Sensor. The lever moves up or down depending on the presence or absence of document, and the end of the lever is scanned by the CIS Sensor. According to the scan result, the printer determines whether document is present or not.

Additionally, there is a Sub Document Lever beside the ADF Document Lever. If the CIS Sensor cannot scan the end of the Sub Document Lever, the printer determines that the scanner (SCN) unit is open or the CIS Sensor is malfunctioning.

No document on ADF	Document is present on ADF
ADF top
PF Roller
ADF document lever

		Lever of ADF PE Sensor
CIS Sensor				ADF inside
Figure 1-13. Document Feed Path

ADF document lever Subdocument

lever

ADF bottom

Sub document lever ADF document lever

Figure 1-14. ADF document lever

Operating Principles

Scanner/ADF Overview

21

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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

Revision G

1.3 Paper Loading/Feed Mechanism

1.3.1 Overview

1.3.1.1 Paper Loading Method

Paper loading method differ between ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET-3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series and ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series, but the both paper loading mechanisms are driven by the PF Motor.

Table 1-5. Paper Loading Method and Drive Force

Drive		Paper loading operation
force	Motor control	Front paper loading	Rear paper loading
(motor)		model	model
PF Motor	PF encoder/	• Turn the Slider Trans to	• Drive the LD Roller and
	PF scale	ASF mode, drive the	loadpaperfromthe ASF
		PickupRollerAssy,and	Rear.
		load paper from the	• Drive the Hopper/Paper
		cassette.	Back Lever to prevent
		• Paper loaded from the	multi-feed.
		cassette is fed to the PF	• Drive the PF Roller/EJ
		Roller by the	Roller to convey the
		intermediate roller	paper.
		inside the duplex unit.	• To flip paper for duplex
		• Drive the PF Roller/EJ
			printing, drive the
		Roller to convey the	intermediate roller
		paper.	inside the duplex unit.
			The paper is flipped and
			then fed to the PF
			Roller.

The following describes which paper loading method is used for which model.

Front paper loading

ET-4750/ET-4760/L6190/ST-4000 series/ET-3750/ET- 3760/L6170/ST-3000 series/ET-3700/ET-3710/L6160 series/

Rear paper loading

ET-2750/ET-2760/L4160/ST-2000 series/ET-2700/L4150 series

Operating Principles	Paper Loading/Feed Mechanism	22
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Front paper loading model	Pick up Roller Assy	Holder Cam Assy
Intermediate roller		Slider Trans
PF Roller
PF Motor		EJ Roller

	PF Encoder
	Cassette
	Rear paper feeding model LD Roller	Clutch
	Hopper	Change Lever
	PF Roller
		EJ Roller

PF Encoder

Stacker

Figure 1-15. Paper loading/feed mechanism

Operating Principles	Paper Loading/Feed Mechanism	23
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Revision G

1.3.1.2 Paper Feed Path

1.3.1.2.1 Front Paper Loading

Paper loaded into the cassette is fed to the intermediate roller by the Pick up Roller Assy, and then arrives at the PE Sensor position.

Next, skew is corrected, and printing on the paper is performed while the paper is being fed by the PF Roller and EJ Roller/Star Wheel Holder Assy, then the paper is ejected to the Stacker.

				PE Sensor
	Intermediate roller
						Star Wheel
Pick up Roller Assy						Holder Assy

EJ Roller

PF Roller

Cassette

Figure 1-16. Paper feed path of front paper loading

1.3.1.2.2 Rear Paper Loading

Paper put on the Hopper is fed by the LD Roller and arrives at the PE Sensor position.

Next, skew is corrected, and printing on the paper is performed while the paper is being fed by the PF roller and EJ Roller/Star Wheel Holder Assy, then the paper is ejected to the Stacker.

LD Roller

Hopper

PE Sensor

Star Wheel

Holder Assy

EJ Roller

PF Roller		Stacker

Figure 1-17. Paper feed path of rear paper loading

Operating Principles	Paper Loading/Feed Mechanism	24
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Revision G

1.3.1.2.3 Paper Loading Path for Auto Duplex Printing

When printing on one side is finished, the printer waits for the ink on the one side to dry keeping the paper nipped between the PF Roller and Driven Roller. After a predetermined drying time has passed, the PF Roller and EJ Roller are rotated in the reverse direction to pull the paper inside the auto duplex unit.

When the leading edge of the paper is detected by the PE Sensor, skew is corrected, and then printing on the back side is performed.

PE Sensor

Intermediate roller

Star Wheel

Holder Assy

EJ Roller

PF Roller

Figure 1-18. Paper feed path for auto duplex printing (back side printing)

Operating Principles	Paper Loading/Feed Mechanism	25
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Revision G

1.3.2 Operation Principle

1.3.2.1 Drive Path

1.3.2.1.1 Drive Path of Front Paper Loading Model

The drive force of the PF Motor is transmitted to the PF Roller and EJ Roller through the compound gear and the spur gear, and then transmitted from the PF Roller to the paper feed mechanism. There are two drive paths; duplex unit system (p 27) and Pick up Roller Assy system (p 28).

DRIVE PATH FROM PF MOTOR TO PF ROLLER/EJ ROLLER

PF Motor

Compound gear PF1

PF Roller

Spur gear PF1

Spur gear PF2

Spur gear PF1

EJ Roller

Duplex unit system

PF Motor

Pick up Roller Assy system

PF Roller

EJ Roller

PF Motor

PF Encoder

EJ gear

Spur gear

PF1

Compoundgear						EJ Roller
PF1		PF Roller		Spur gear PF2

Figure 1-20. Drive path from PF Motor to PF Roller/EJ Roller (2)

Figure 1-19. Drive path from PF Motor to PF Roller/EJ Roller (1)
Operating Principles	Paper Loading/Feed Mechanism	26
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Revision G

DRIVE PATH FROM PFROLLER TO INTERMEDIATE ROLLER

(DUPLEX UNIT SYSTEM)

The intermediate roller always rotates in the paper feed direction because of the one way clutch, regardless of the PF roller rotational direction.

The one way clutch is consist of the sun gear, the external gear (x2) on both sides of the sun gear, and the planetary gear (x5 each) inside the external gear. When the sun gear rotates, either one of the external gears idle being disengaged from the planetary gears, while the external gear on the other side rotates being engaged with the planetary gears. In this way, the one way clutch is designed to rotate either one of the two external gears at a time, and which one to rotate depends on the rotational direction of the sun gear.

PF Roller (spur gear 9)

Compound gear 28.8-14.4

Spur gear 22.8

One way clutch

Sun gear

Planetary gear (x5)			Planetary gear (x5)
External gear B (80 digit side)			External gear A (0 digit side)
Spur gear 17.28			Spur gear 17.28
			Spur gear 17.28

Spur gear 16/spur gear duplex

PF Motor

PF Roller

Compoundgear

28.8-14.4

Spur gear 22.8

Spur gear 17.28

Intermediate Roller Oneway clutch

Spur gear 16/Spur gear duplex

Spur gear 17.28

Structure of one way clutch	Rotational direction of sun gear and motion
	of external gear seen from 0 digit side
Sun gear	Sun gear
External
gear A	Clockwise	Counterclockwise
	External
	gear B
External	Idle	Rotate
gear B
Planetary gear	External
	gear A
	Rotate	Idle

	Intermediate roller	Figure 1-22. Drive Path From PF Roller to Intermediate Roller (2)
Figure 1-21. Drive Path From PF Roller to Intermediate Roller (1)
Operating Principles		Paper Loading/Feed Mechanism	27

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EPSON ET-4750/4760/3750/3760/3700/3710/2750/2760/2700/L6190/L6170/L6160/L4160/L4150/ST-4000/ST-3000/ST-2000 series

Revision G

DRIVE PATH FROM PFROLLER TO PICK UPROLLER (PICK UPROLLER ASSYSYSTEM)

If the Pick up Roller Assy is always driven by the PF motor, it continues feeding paper without stopping regardless of the progress of printing on the previous sheet. To prevent this, the Slider Trans interrupts the motor drive to the Pick up Roller Assy when the assy needs to stop.

While the Pick up Roller Assy needs to move, the Slider Trans is pulled toward the opposite side of the carriage home with the tension spring. The transmission gear interlocked with the Slider Trans engages with the Pick up Roller driving gear (one way clutch) that moves the Pick up Roller Assy, so the Pick up Roller Assy can be driven by the PF Motor. If the CR Unit pushes the Change Lever to the 0 digit side, the transmission gear disengages from the one way clutch. As a result, the driving force of the PF Motor is shut down.

The CR Unit pushes the Slider Trans to the 0 digit side to stop the Pick up Roller Assy after a sheet of paper is fed into the printer, however, the CR Unit cannot stay at the position because it needs to move for printing. Therefore, instead of the CR Unit, the Change Lever’s disengaged status is kept by the cam of the Holder Cam Assy during printing.

PF Roller (spur gear 9)

Compound gear 28.8-14.4

Spur gear 17.6 (Slider Trans)

One way clutch

External gear

Planetary gear (x3)

Sun gear

Spur gear 28

Pick up drive shaft

Spur gear 16B

Spur gear 16

Spur gear 16B

Spur gear 16

Pick up Roller

Figure 1-23. Drive path from PF roller to Pick up Roller Assy (1)

The one way clutch controls the Pick up Roller to rotate only in the paper feed direction. The operation principle and the structure are basically the same with the one used in the drive path to the intermediate roller (p 27). Therefore, while the PF Roller is rotating in the direction opposite to the paper feed direction, the Pick up Roller does not rotate even when the drive force is transmitted through the Slider Trans.

When drive force of PF Motor is not transmitted

Holder

CamAssy

Spur gear 17.6 (Slider Trans)

Compound gear 28.8-14.4

One way clutch

External gear

Sun gear

Spur gear 28

Planetary

gear Spurgear 16

CR Unit

Pick up drive shaft

PF Roller

Pick up Roller

Spur gear 16B

Figure 1-24. Drive path from PF roller to Pick up Roller Assy (2)

Operating Principles

Paper Loading/Feed Mechanism

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Revision G

1.3.2.1.2 Drive Path of Rear Paper Loading Model

The drive path of the rear paper loading model is mostly the same with the front paper loading model. The driving force of the PF Roller is transmitted to the PF Roller and the EJ Roller through the compound gear and the spur gear, and then transmitted from the PF Roller to the paper feed mechanism. There are two drive paths; duplex unit system (p 30) and ASF Rear system (p 31).

DRIVE PATH FROM PF MOTOR TO PF ROLLER/EJ ROLLER

PF Motor

Compound gear PF1

PF Roller

Spur gear PF1

Spur gear PF2

Spur gear PF1

EJ Roller

Figure 1-25. Drive path from PF Motor to PF Roller/EJ Roller (1)

Duplex unit system

Hopper

ASF Rear system

PF Motor

PF Roller

EJ Roller

PF Motor		PF Encoder		EJ gear

Spur gear PF1

Compound	PF Roller Spur gear PF2 EJ Roller
gear PF1

Figure 1-26. Drive path from PF Motor to PF Roller/EJ Roller (2)

Operating Principles	Paper Loading/Feed Mechanism	29
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Revision G

DRIVE PATH FROM PFROLLER TO INTERMEDIATE ROLLER

(DUPLEX UNIT SYSTEM)

The intermediate roller always rotates in the paper feed direction because of the one way clutch, regardless of the PF roller rotational direction.

The one way clutch is consist of the sun gear, the external gear (x2) on both sides of the sun gear, and the planetary gear (x5 each) inside the external gear. When the sun gear rotates, either one of the external gears idle being disengaged from the planetary gears, while the external gear on the other side rotates being engaged with the planetary gears. In this way, the one way clutch is designed to rotate either one of the two external gears at a time, and which one to rotate depends on the rotational direction of the sun gear.

PF Roller (spur gear PF)

Compound gear 27.2-22.2

Compound gear 38.4-15.6

One way clutch

Sun gear

Planetary gear (x5)			Planetary gear (x5)
External gear B (80 digit side)			External gear A (0 digit side)
Spur gear 21.6			Spur gear 21.6
			Spur gear 21.6

Spur gear16/spur gear duplex

Intermediate roller

Figure 1-27. Drive Path From PF Roller to Intermediate Roller (1)

PF Motor

PF Roller

	Compound gear	Oneway
		clutch
	27.2-22.2

Compound gear 38.4-15.6

Spurgear

21.6

Intermediate roller

Change	Spur gear 16/Spur gear duplex
Lever	Spur gear 21.6
Structure of one way clutch		Rotational direction of sun gear and motion
		of external gear seen from 0 digit side
	Sun gear	Sun gear
External		Clockwise	Counterclockwise
gear A
		External
		gear B
	External	Idle	Rotate
	gear B
	Planetary gear	External
		gear A
		Rotate	Idle

Figure 1-28. Drive Path From PF Roller to Intermediate Roller (2)

Operating Principles

Paper Loading/Feed Mechanism

30

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