Epson LX-300 Plus Service Manual

Service Manual

Service ManualService Manual

EPSON LX-300+

9-pin Serial Impact Dot Matrix Printer

TM-LX300+

EPSON LX-300+

EPSON

LX-300+ Dot Matrix Printer

Service Manual

iii

EPSON LX-300+



2000 Epson America, Inc.

3480 Kilroy Airport Way, Long Beach CA, 90806-2469

All rights reserved. No part of this publication 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 written permission of Epson America, Inc.

Epson America, Inc., assumes no liability for damages resulting from the use of the information contained herein. While every precaution has been taken in the preparation of this book, Epson America, Inc. assumes no responsibility for errors and omissions.

Neither Epson America, Inc., nor its affiliates shall be liable to the purchaser of this product or third parties for damages, losses, costs, or expenses incurred by the purchaser or third parties as a result of: accident, misuse, or abuse of this product or unauthorized modifications, repairs, or alterations to this product.

Epson America, Inc. shall not be liable for any damages or problems arising from the use of any options or any consumable products other than those designated as Original EPSON-Approved Products by Seiko Epson Corporation.

Trademark Information

EPSON® and ESC/P® are registered trademarks of Seiko Epson.

Epson Connection

General Notice: Other product names used herein are for identification purposes only and may be trademarks of their respective companies. EPSON disclaims any and all rights in those marks.

is a service mark of Epson America, Inc.

EPSON LX-300+

FCC Compliance Statement for American Users

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio and television reception.

However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause interference to radio and television reception, which can be determined by turning the equipment on and off, the user is encouraged to try to correct the interface by one or more of the following measures:

! Reorient or relocate the receiving antenna.

! Increase the separation between the equipment and receiver.

! Connect the equipment into an outlet on a circuit different from that

to which the receiver is connected.

! Consult the dealer or an experienced radio/television technician

for help.

Warning

The connection of a non-shielded equipment interface cable to this equipment will invalidate the FCC Certification of this device and may cause interference levels that exceed the limits established by the FCC for this equipment. It is the responsibility of the user to obtain and use a shielded equipment interface cable with this device. If this equipment has more than one interface connector, do not leave cables connected to unused interfaces.

Changes or modifications not expressly approved by the manufacturer could void the user’s authority to operate the printer.

For Canadian Users

This Class B digital apparatus meets all requirements of the Canadian Interface-Causing Equipment Regulations.

Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le materiel brouilleur du Canada.

EPSON LX-300+

Guide to Using This Manual

Symbols Used in This Manual

Before servicing the EPSON LX-300+, read the precautions on the following page. Then turn to one of these chapters:

Chapter 1. Product Basics

Lists the main features of the product and describes basic control panel operations.

Chapter 2. Technical Overview

Explains how the product works.

Chapter 3. Troubleshooting

Tells how to identify and correct common problems.

Chapter 4. Disassembly and Assembly

Provides step-by-step instructions for disassembling the product.

Chapter 5. Adjustments

Provides instructions for adjusting the platen gap and bi-directional print alignment.

Chapter 6. Maintenance

Describes routine maintenance procedures.

W A R N I N G

C A U T I O N

R E A S S E M B L Y

Warnings must be followed to avoid personal injury or death.

Cautions must be followed to avoid damaging the product.

Reassembly notes provide helpful tips for reassembly.

Chapter 7. Appendix

Provides additional information for reference:

" Detailed specifications

" Connector pin assignments

" Electrical diagrams

" Parts list

" Exploded diagrams

EPSON LX-300+

General Precautions

W A R N I N G

" When servicing, unplug the unit from the power

outlet and disconnect any attached devices.

" Never touch the primary parts of the power supply

(including the heat sink) when the unit is plugged in. Its primary circuitry remains live whenever it is plugged in.

" No work should be performed on the unit by

persons unfamiliar with basic safety measures familiar to trained electronics technicians.

" When performing testing or troubleshooting

procedures in this manual, do not connect the unit to a power source until instructed to do so. When the power supply cable must be connected, use extreme caution in working on the power supply board and other electronic components.

C A U T I O N

" Repairs on EPSON products should be performed

only by an EPSON-certified repair technician.

" Make certain that the source voltage is the same

as the rated voltage listed on the serial number plate. If the unit has a primary AC rating different from the available power source, do not connect it to the power source.

" Always verify that the unit has been disconnected

from the power source before removing or replacing printed circuit boards and other components.

" To protect sensitive microprocessors and

circuitry, use static discharge equipment, such as anti-static wrist straps, when accessing internal components.

" Always replace malfunctioning components with

EPSON components. Introduction of secondsource ICs or other non-approved components may damage the product and void any applicable EPSON warranty.

vii

EPSON LX-300+

viii

Chapter 1 Product Basics

1.1 Features ............................................................................................ 13

1.2 Control Panel Operation ................................................................. 14

1.2.1 Control Panel ............................................................................. 14

1.2.1.1 Switches ............................................................................. 14

1.2.1.2 Indicator Lights (LEDs) ....................................................... 15

1.2.1.3 Beeper ................................................................................ 15

1.2.2 Default Setting Mode ................................................................. 16

1.2.3 Bi-D Adjustment ........................................................................ 17

1.3 Accessories ..................................................................................... 17

Chapter 2 Technical Overview

2.1 Printer Mechanism .......................................................................... 21

2.1.1 Printhead ................................................................................... 22

2.1.2 Carriage Mechanism ................................................................. 23

2.1.3 Color Ribbon Mechanism (Optional) ......................................... 25

2.1.4 Platen Gap Adjustment Mechanism .......................................... 26

2.1.5 Paper Feed Mechanism ............................................................ 27

2.2 Electronics ....................................................................................... 28

2.2.1 Main Board ................................................................................ 28

2.2.2 Power Supply Board .................................................................. 29

2.2.3 Initialization ................................................................................ 30

2.2.4 Other Special Functions ............................................................ 30

Chapter 3 Troubleshooting

3.1 Overview .......................................................................................... 33

3.1.1 Precautions ............................................................................... 33

3.2 Printer Self-Diagnostics .................................................................. 33

3.2.1 Indicator LEDs ........................................................................... 33

3.2.2 Self-Test .................................................................................... 34

3.3 Troubleshooting by Printer Symptoms ......................................... 34

3.4 Test Points ....................................................................................... 37

3.4.1 Printhead Check ........................................................................ 37

3.4.2 Motor Check .............................................................................. 38

3.4.3 Sensor Check ............................................................................ 38

3.4.4 Printhead Driver Check ............................................................. 38

Chapter 4 Disassembly and Assembly

4.1 Overview .......................................................................................... 41

4.1.1 Precautions ............................................................................... 41

4.1.2 Tools ......................................................................................... 41

4.2 Disassembly .................................................................................... 42

4.2.1 Preparation ................................................................................ 42

4.2.2 Printhead Removal .................................................................... 42

4.2.3 Upper Housing Removal ........................................................... 43

4.2.4 Printer Mechanism Removal ..................................................... 44

4.2.5 Control Panel Board Removal ................................................... 45

4.2.6 C294MAIN Board Removal ....................................................... 45

4.2.7 Power Supply Board Removal .................................................. 46

4.2.8 Printer Mechanism Disassembly ............................................... 47

4.2.8.1 Carriage (CR) Motor Removal ............................................ 47

4.2.8.2 Platen Removal .................................................................. 48

4.2.8.3 Carriage Removal .............................................................. 49

4.2.8.4 Ribbon Feed Mechanism Disassembly .............................. 50

4.2.8.5 BPE and RPE Sensor Removal ......................................... 51

4.2.8.6 Home Position (HP) Sensor Removal ................................ 51

4.2.8.7 Platen Gap (PG) Sensor Removal ..................................... 52

4.2.8.8 Removing the Tractor Release Lever Sensor .................... 52

4.2.8.9 Paper Feed (PF) Motor Removal ....................................... 53

4.2.8.10 Removing the Tractor Drive Gears ................................... 53

4.2.8.11 Paper Guide Removal ...................................................... 54

Chapter 5 Adjustments

5.1 Platen Gap Adjustment ................................................................... 59

5.2 Bidirectional Adjustment ................................................................ 60

Chapter 6 Maintenance

6.1 Overview ........................................................................................... 67

6.1.1 Cleaning .................................................................................... 67

6.1.2 Lubrication ................................................................................. 67

Chapter 7 Appendix

7.1 Electrical Connections .................................................................... 73

7.1.1 Connector Summary ................................................................. 73

7.1.2 Connector Pin Assignments ...................................................... 73

7.2 Printing Specifications .................................................................... 76

7.2.1 Printing Specification ................................................................. 76

7.2.2 Paper Feeding ........................................................................... 79

7.2.3 Electrical Specification .............................................................. 80

7.2.4 Environmental Condition ........................................................... 80

7.2.5 Reliability ................................................................................... 80

7.2.6 Ribbon Cartridge ....................................................................... 80

7.2.7 Safety Approvals ....................................................................... 81

7.2.8 CE Marking ................................................................................ 81

7.2.9 Acoustic noise ........................................................................... 81

7.2.10 Printable Area .......................................................................... 82

7.3 Interface Specifications .................................................................. 85

7.3.1 Parallel Interface (Forward Channel) ........................................ 85

7.3.2 Parallel Interface (Reverse Channel) ........................................ 87

7.3.3 Serial Interface .......................................................................... 88

7.3.4 Interface Selection .................................................................... 89

7.3.5 Preventing Data Transfer Time-out ........................................... 89

7.3.6 IEEE1284.4 protocol ................................................................. 89

7.4 Control Codes .................................................................................. 90

7.4.1 ESC/P2 ..................................................................................... 90

7.4.2 IBM 2390 Plus Emulation .......................................................... 91

7.4.3 Bi-Directional Commands ......................................................... 92

7.4.3.1 Reply Printer Status ........................................................... 94

7.4.3.2 Packet commands .............................................................. 95

7.5 Paper Specifications ....................................................................... 96

7.6 Physical Specifications .................................................................. 99

7.7 Parts List ........................................................................................ 100

7.8 Exploded Diagrams ....................................................................... 103

7.9 Circuit Diagrams ............................................................................ 105

PRODUCT BASICS

CHAPTER

EPSON LX-300+ Product Basics

1.1 Features

The EPSON LX-300+ is a 9-pin serial impact dot matrix printer. Its major features include:

Printing speed: High speed draft 300 cps at 10 cpi

Draft 225 cps at 10 cpi NLQ 56 cps at 10 cpi

Feeding method: Friction feed (rear)

Push tractor feed (rear) Push and Pull tractor feed (rear) Pull tractor feed (rear, bottom)

Feeder: Standard: Rear push tractor

Optional: Cut sheet feeder bin, Pull tractor, and Roll paper holder

Paper/ Media: Single sheets, Continuous paper, Multi-part forms,

Envelopes, Labels, and Roll paper

Fonts: 2 NLQ and 1 Draft Bitmap typefaces

8 Barcode fonts

Character tables: Standard version 13 tables

NLSP version 38 tables

Input buffer: 8 Kbytes

Acoustic noise: 49 dB(A) (ISO 7779 pattern)

Reliability: Total print volume 12 million lines

(except printhead) MTBF 6000 POH (25% Duty) Printhead life 200 million strokes per pin Ribbon life 3 million characters

Paper guide cover

Printer cover

Control panel

Parallel interface

Figure 1-1. EPSON LX-300+ Printer Parts

Tractor

Power cord

Paper supports

Paper guide

Tractor release lever

Knob

Ribbon cartridge

Paper thickness

lever

Paper tension unit

Power switch

Interface: Bi-directional parallel interface

(IEEE-1284 nibble mode supported) Serial I/F

Control code: ESC/P and IBM 2380 Plus emulation

Copy capability: 1 original + 4 copies

(CONTINUED)

EPSON LX-300+ Product Basics

1.2 Control Panel Operation

1.2.1 Control Panel

The control panel includes four switches and four LEDs:

Font Indicator LEDs

Tear Off

Draft

Draft Condensed Roman

Roman Condensed

Sans serif

Sans serif Condensed

: LED On

: LED Blinks

Figure 1-2. Control Panel

Tear Off

Font

LF/FF

Micro Adjust

: LED Off

Load/

Paper

Pause

1.2.1.1 Switches

Operation in normal mode

Table 1-1. Operation in Normal Mode

Button Function

• Pauses printing

Pause

Load/Eject

LF/FF

Tear Off

Operation at power on

Turning the printer on while pressing these buttons executes the following functions:

• Enables Micro Adjust and Font selection (held down for 3 seconds)

• Loads or ejects paper

• Executes micro feed forward (0.118 mm or 1/216 inch) when this function is enabled

• Executes line feed (pressed momentarily)

• Executes form feed (held down for 3 seconds)

• Executes micro feed backward (0.118 mm or 1/216 inch) when this function is enabled

• Advances continuous paper to the Tear-off position; pressing it a second time returns paper to TOF

• Selects font, when this function is enabled

Table 1-2. Operation at Power On

Button Function

Load/Eject NLQ self test

LF/FF Draft self test

Tear Off Enters default setting mode

Load/Eject & LF/FF Data dump

EPSON LX-300+ Product Basics

Table 1-2. Operation at Power On (continued)

Button Function

Clear EEPROM (returns printer to factory default settings)

Load/Eject & LF/FF & Pause

Tear Off & Load/Eject & LF/FF Clear ribbon usage counter (stored in EEPROM)

Pause

Operation in default setting mode

NOTE: Factory default settings aren’t necessarily correct for your market; use only if necessary.

Perform Bi-D adjustment (see page 17 and page 60)

Default setting mode is entered by holding down the Tear Off button and turning the printer on. The following buttons are used in default setting mode:

Table 1-3. Operation at Power On

Button Function

Tear Off Changes the setting

LF/FF Selects the Menu

For more information, see “Default Setting Mode” on page 16.

1.2.1.2 Indicator Lights (LEDs)

The Pause and Paper Out lights indicate these conditions:

Table 1-4. Printer Status

Printer Status Pause Paper Out

Pause On ---

Paper out error On On

Release lever error On ---

Paper eject warning On Blink

Micro Adjust Blink ---

When all four lights are blinking, the printer has a fatal error (caused by a carriage control or power supply failure).

When both Font lights blink, paper is in the tear-off position. When the paper is positioned for printing, the Font lights indicate the currently selected font:

: Draft

: Draft Condensed

: Roman

: Roman Condensed

: Sans serif

: Sans serif Condensed

: Tear Off

(

: LED On, ": LED Off, $: LED Blinks)

1.2.1.3 Beeper

Paper out error: three beeps

Release lever operation: three beeps

Illegal panel operation: one short beep

EPSON LX-300+ Product Basics

1.2.2 Default Setting Mode

You can change the printer’s default settings by following these steps:

1. Turn the printer on while pressing Tear Off. The printer prints a set of instructions.

2. Follow the printed instructions to change these default settings (standard factory settings are underlined):

Table 1-5. Default Settings

Item Setting / Value *2

3 inch, 3.5 inch, 4 inch, 5.5 inch, 6 inch, 7 inch,

Page length for tractor

Skip over perforation OFF, ON

Auto tear off OFF

Auto line feed OFF, ON

Print direction Bi-d.

Software ESC/P, IBM 2390 Plus

0 slash OFF

High speed draft OFF, ON

8 inch, 8.5 inch, 11 inch 17 inch

, ON

, Uni-d., Auto

, ON

, 70/6 inch, 12 inch, 14 inch,

Table 1-5. Default Settings (continued)

Item Setting / Value *2

Character table Software version

Italic, PC437 BARASCII, Abicomp, Roman8, ISO Latin 1, PC858, ISO 8859-15

NLSP version Italic, PC437 PC852, PC857, PC864, PC866, PC869, MAZOWIA, Code MJK, ISO 8859-7, ISO Latin 1T, Bulgaria, PC774, Estonia, ISO 8859-2, PC 866 LAT., PC 866UKR, PC APTEC, PC708, PC720, PCAR 864, PC860, PC865, PC861, PC863, BRASCII, Abicomp, Roman8, ISO Latin 1, PC858, ISO 8859-15, PC771

International character set for Italic table

Manual feed wait time 1 second, 1.5 seconds, 2 seconds, 3 seconds

Buzzer OFF, ON

Auto CR (IBM 2380 Plus) OFF, ON

IBM character table Table2

Italic U.S.A. U.K., Italic Denmark 1, Italic Sweden, Italic Italy, Italic Spain 1

, PC850, PC860, PC863, PC865, PC861,

, PC850, PC437, Greek, PC853, PC855,

, Italic France, Italic Germany, Italic,

, Table1

I/F mode Auto, Parallel, Option

Auto I/F wait time 10 seconds, 30 seconds

Parallel I/F bidirectional mode

Packet mode Auto, OFF

Auto CR (IBM 2390 Plus) OFF

A.G.M. (IBM 2390 Plus) OFF, ON

OFF, ON

, ON

EPSON LX-300+ Product Basics

1.2.3 Bi-D Adjustment

Users can perform the bi-directional adjustment themselves if they notice jagged characters or misaligned vertical lines. Follow these steps:

1. Turn the printer on while pressing Pause. The printer prints a set of instructions along with the first alignment pattern.

2. Follow the printed instructions to adjust the alignment for each of the following print speeds:

high speed draft mode

draft mode

NLQ mode

3. Turn the printer off. The settings are stored in the printer’s memory.

To perform the Bi-D adjustment using the adjustment program, see page 60.

1.3 Accessories

Table 1-6. Consumables

Item Description

Ribbon cartridge (Black) #8750

Ribbon pack (Black) #8758

Ribbon cartridge (Color) S015073

Table 1-7. Options

Item Description

Cut sheet feeder C806371

Pull tractor unit C800301

Roll paper holder #8310

Color upgrade kit C832081

EPSON LX-300+ Product Basics

TECHNICAL OVERVIEW

CHAPTER

EPSON LX-300+ Technical Overview

2.1 Printer Mechanism

The printer’s main components are shown below:

Rear paper end sensor

Bottom paper end sensor

Platen

Adjust lever

Platen gap sensor

Ribbon Feed Mechanism

Carriage

Carriage home position sensor

Ribbon

Printhead

Tractor

Release sensor

Release mechanism

Paper feed

motor

Carriage guide shaft

Timing belt

Carriage motor

Figure 2-1. Printer Mechanism Block Diagram

EPSON LX-300+ Technical Overview

2.1.1 Printhead

The printhead’s pins are configured as shown below. (The view is from behind the printhead, facing the platen.)

Figure 2-2. Pin Configuration

The table below indicates printhead specifications:

Table 2-1. Printhead Specifications

Item Specification

Number of pins 9

Pin diameter 0.29 mm

Coil resistance 33.3 ±3.3 Ω (25°C)

Head drive voltage 35 +2.1/-3.5 V

• Normal: 0.75 A (Standard)

Peak current

Head drive frequency

Head life

Environmental conditions

The printhead also works as the printer’s beeper; to generate sound, the driver causes the pins to vibrate at a high frequency.

• Copy: 0.85 A (Standard)

1.0 A (Maximum)

• Normal: 1350Hz or less

• Copy: 1350Hz or less

• Black ribbon: 0.2 billion stroke per pin or more

• Color ribbon: 0.1 billion strokes per pin or more

• Temperature: 5 to 55°C

• Humidity: 10 to 85%

Table 2-2. Beeper Drive Specifications

Item Specification

Head voltage 35 +2.1/-3.5 V

Drive frequency 2 KHz, 1.5KHz

EPSON LX-300+ Technical Overview

2.1.2 Carriage Mechanism

Home Position Sensor

The printer uses a mechanical contact switch to determine when the carraige is at home position (on the left side of the printer). The switch is OPEN when the carriage is in home position, and CLOSED when away from home position.

Carriage Motor

This printer uses a DC stepper motor.

Table 2-3. CR Motor Specifications

Item Specification

Motor type 2-phase, 200-pole hybrid stepper motor

Coil resistance 5.7 Ω ±10% (25°C)

Control method Bi-polar drive

Phase drive 2-2 phase, 1-2 phase, W1-2 phase

Drive voltage 36.75 ±1.75 V

CR feed pitch

Minimum Resolution:

0.212 mm (1/120”) (1-2 phase, 2 pass)

Under certain conditions, the carriage can move at different speeds. For example, when printing on thicker paper such as multipart forms, the carriage slows to avoid breaking off printhead pins. When printing blank areas of the page, the carriage speeds up.

The table on the following page indicates the various speeds at which the carriage travels.

EPSON LX-300+ Technical Overview

The following table indicates the various carriage speed modes:

Table 2-4. Carriage Speed Modes

Carriage

speed

mode

A 3600

B 3375

C 2700

D 2250

E 1800

F 1350 Both 1-2 0.65 0.65 0.59 0.59 0.59 120 1350

G 1125 Both 1-2 0.65 0.65 0.59 0.59 0.59 144 1350 Bit image 144 dpi I low

H 900 Both 1-2 0.65 0.65 0.59 0.59 0.59 180 1350 NLQ 15cpi I low

I 675 Both 1-2 0.65 0.65 0.59 0.59 0.59 240 1350 NLQ 17/20cpi J low

J 450 Both 1-2 0.65 0.65 0.59 0.59 0.59 - low

CR drive

frequency

[Hz]

Printing

mode

Color 2-2 0.79 0.79 0.70 0.70 0.70

BW 2-2 0.70 0.59 0.59 0.59 0.59

Color 2-2 0.79 0.79 0.70 0.70 0.70

BW 2-2 0.70 0.59 0.59 0.59 0.59

Color 2-2 0.79 0.79 0.70 0.70 0.70

BW 2-2 0.70 0.59 0.59 0.59 0.59 Draft 12cpi

Color 2-2 0.79 0.79 0.70 0.70 0.70 1440/21 1286

BW 2-2 0.70 0.59 0.59 0.59 0.59 72 1350 Bit image 72 dpi

Color 2-2 0.79 0.79 0.70 0.70 0.70 80 1200 Bit image 80 dpi

BW 1-2 0.65 0.65 0.59 0.59 0.59 90 1350

Phase

drive [pps]

Front

rush

Current limit (A/phase) Adjacent

High

speed

Normal

speed

Low

speed

Rear rush

dot

resolution

[dpi]

45 1350

48 1350

60 1350

Head drive

frequency

[Hz]

Printing speed

High speed draft 10cpi

High speed draft 12cpi

High speed draft 15cpi Draft 10cpi Bit image 60 dpi

High speed draft 17cpi

High speed draft 20cpi Draft 15cpi Bit image 90 dpi

Draft 20/17cpi NLQ 10cpi Bit image 120 dpi

Carriage

speed mode

at power

down

Chigh

Ehigh

Fhigh

F high

Glow

Ilow

High or

low

speed

printing

EPSON LX-300+ Technical Overview

2.1.3 Color Ribbon Mechanism (Optional)

The color ribbon mechanism (color shift, or CS, mechanism) shifts the color ribbon up and down to change the color area of the ribbon.

The mechanism includes a sensor (mechanical contact switch) to detect the presence of a ribbon cartridge. If one is installed, the output is HIGH; if not installed, the output is LOW.

To avoid unwanted mixing of colors, composite colors are applied in a specific order. The following table shows how green, violet, and orange are composed:

Table 2-5. Color Printing Order

Composite Color First color Second color

Green Yellow Cyan

Orange Yellow Magenta

Violet Magenta Cyan

The color ribbon mechanism uses a stepper motor with these specifications:

Table 2-6. Color Shift Motor Specifications

Item Specification

Motor type 2-phase, 48-pole PM stepping motor

Coil resistance 150 Ω ±5% (25°C, per 1 phase)

Control method uni-polar rated voltage drive

Phase drive 2-2 phase

Ribbon Initialization

During printer initialization, the ribbon is positioned for black printing. At the same time, the carriage moves to prevent the ribbon from getting caught on it. This initialization also takes place when the print buffer clears or the printer is paused.

Color ribbon drive circuit

Ribbon detector

CS motor

CS lever assembly

CS cam

CS lever assembly

Color ribbon

Black

Cyan

Magenta

Yellow

Color cartridge holder

Drive voltage 36.75 ± 1.75 VDC

Consuming current

Drive frequency 500 pps

• Operating, peak current: 245 mA

• Non-operating: 20 mA

CS motor, pinion

CS cam

Figure 2-3. Color Ribbon Mechanism

EPSON LX-300+ Technical Overview

2.1.4 Platen Gap Adjustment Mechanism

The platen gap lever changes the distance between the printhead and the platen. This lets the printer print on thicker paper.

When printing on thick paper or multipart forms, the lever is set to position 1, 2, 3, or 4. The lever trips the platen gap sensor (a mechanical contact switch) and causes the carriage to move at a slower speed; this prevents printhead pins from getting lodged in the paper and breaking off.

Table 2-7. PG Sensor Specifications

Item Specification

Electrical rating 0.6 to 1.0 mA, 5 V ±5%

Switching mode

• PG=0: closed

• PG=1-4: open

Parallelism adjust

bushing

PG_SW

Adjust lever

Platen gap

Platen

Carriage guide shaft

Carriage

Parallelism adjust

bushing

Printer mechanism

Printhead

Adjust lever

Carriage

Carriag e guide shaft

Figure 2-4. Platen Gap Adjustment Mechanism

EPSON LX-300+ Technical Overview

2.1.5 Paper Feed Mechanism

The are two standard ways of feeding paper through the printer: by friction feeding and by using the push tractor.

When friction feeding, set the tractor release lever to cut sheet paper.

When you insert the paper into the rear loading slot, the RPE sensor detects the paper and the printer automatically advances it to the TOF position.

When using tractor feeding, set the tractor release lever to the tractor

position. The paper feed motor disengages from the paper feed rollers and transfers drive to the tractor. The mechanism is shown below:

Compression spring

Plain

washer

Printer mechanism

Tractor gear

Tractor release

Paper

advance

reduction

gear

lever

Release

detector

The paper feed motor has the following specifications:

Table 2-8. PF Motor Specifications

Item Specification

Motor type 2-phase, 96-pole hybrid stepper motor

Coil resistance 16.0 Ω ±10% (25°C)

Control method Bi-polar rated current drive

Phase drive 1-2 phase, W1-2 phase

Drive voltage 36.75 ±1.75 VDC

Drive current 0.1 to 0.9A

Paper feed pitch

Minimum Resolution:

0.059 mm (1/432”) (1-2 phase, 2 pass)

The printer includes two sensors to detect the end of the paper: the RPE sensor detects paper fed through the rear paper slot; the BPR sensor detects paper fed through the bottom paper slot. The sensors have the following specifications:

Table 2-9. RPE and BPE Sensor Specifications

Item Specification

Type Mechanical contact switch

Electrical rating 0.6 to 1.0 mA, 5 VD±5%

Switching mode

• Paper inside: open

• No paper: closed

PF motor

Figure 2-5. Tractor Release Mechanism

Standard feeding methods allow continuous forms to be fed through the rear loading slot, using either friction or push-tractor feeding; or cut sheet paper can be fed through the top loading slot, one sheet at a time, using friction feeding. Other feeding methods include using the optional cut sheet feeder, pull tractor unit, and roll paper holder.

The printer also uses a sensor (a contact switch) to detect the position of the tractor release lever. When friction feeding, the switch is OPEN; when tractor feeding, the switch is CLOSED.

EPSON LX-300+ Technical Overview

2.2 Electronics

2.2.1 Main Board

The components of the main board are diagrammed below and explained on the next page.

Control Panel

HP sensor

RPE Sensor

Release Sensor

BPE Sensor

PG Sensor

Figure 2-6. Main Board Block Diagram

EPSON LX-300+ Technical Overview

Table 2-10. Main Board Components

Elements Location Function

RISC C33208 CPU, QFP 128 pin

• Outside clock 19.66 MHz

CPU IC3

G/A

PROM IC7

DRAM IC8

EEPROM IC5

RESET IC IC4

CR Motor Driver IC9 LB1847 (SANYO)

PF Motor Driver IC10 LB1847 (SANYO)

Serial I/F Transceiver IC2 HIN202CBN or equivalent

Regulator IC IC11

Regulator IC IC12

Thermistor TH1 Measures temperature of the motor driver.

IC6

Inside clock 39.32 MHz

• 8KB RAM built-in

•DMA

• A/D converter

Approximately 21000 gates, QFP 160 pin

• Bit manipulation

• Clock control

• Interface control (IEEE1284/Type-B I/F)

• Input Buffer control

• Motor control

• Head control

4M / 8Mbit, DIP 40 / 42 pin

• Stores firmware

•CG

1/2/4M bit switching method, SPJ package 40 pin

• Processing buffer

AT93C46, 1kbit, SOP 8pin

• Stores default values and other parameters

M62030 (SANYO), 8 pin

• CPU and G/A reset

BA033 (ROHM) or equivalent

• Generates 3.3V logic voltage

PD494 or equivalent

• 95V rated voltage circuit

• Detects over voltage (over 150V) and sends OFF signal to the power supply boards.

2.2.2 Power Supply Board

The EPSON LX-300+ uses one of two power supply boards: C294PSB (100-volt model) and C294PSE (200-volt model). The table below shows the power supply boards’ input voltage specifications:

Table 2-11. Input Voltage Specifications

Circuit Input voltage Fuse specification

C294PSB 99 - 132VAC ULTSC-2.5A-NI

C294PSE 198 - 264VAC HT 1.25A

Each power supply board supplies power at two voltage levels, as shown below:

Table 2-12. Output Voltage

Output voltage Usage

35 V +5%/-10% Motor drive

5 V ± 5% Logic circuits

Note that the core voltage of the CPU and G/A on the main board is actually

3.3 volts. This is stepped down from 5 volts using a local regulator built onto the main board.

* CPU and G/A will be combined in a later version.

EPSON LX-300+ Technical Overview

2.2.3 Initialization

Printer initialization can be performed in the following ways:

Power-on initialization

This initialization is activated by a power-on or cold-reset command (remote RS command). Purpose:

to initialize the printer mechanism

to execute Operator initialization

Operator initialization

This initialization is activated by the -INT signal (negative pulse). Purpose:

to clear all buffers of data

to cancel the download character definition

to put the printer in stand-by mode, if no errors occur

to execute Software initialization

Software initialization

This initialization is activated by the control code ESC@. Purpose:

to clear the unprinted data

2.2.4 Other Special Functions

Energy Saving Mode

This function saves electricity when the printer is in standby mode. Normally, the PF motor, CR motor, and CS motor are kept stationary by a holding current. In energy saving mode, this current is turned off.

Quiet Mode

Quiet mode lowers printing temperature. When this mode is selected, the carriage speed slows to the power down mode speed. See Table 2-4, “Carriage Speed Modes,” on page 24.

to set the printer’s default settings

+ 78 hidden pages

Epson LX-300 Plus Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Guide to Using This Manual

General Precautions

Contents