Epson Action Printer 3000, LQ-200 Service Manual

®

EPSON

LQ-200

TM

ActionPrinter

Service Manual

Revision Level

3000

I@

Printed on recycled paper.

FCC Compliance Statement

For American Users

This equipment has been tested and found to comply with 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 communications. However, there is no guarantee that

interference will not occur in a particular installation. If this equipment does cause harmful

interference to radio or television reception, which can be determined by turning the equipment off

and on, the user is encouraged to try to correct the interference by one or more of the following

measures:

l

Reorient or relocate the receiving antenna.

l

Increase the separation between the equipment and the receiver.

l

Connect the equipment to an outlet on a circuit different from that to which the receiver is

connected.

l

Consult the dealer or an experienced radio/TV technician for help.

CAUTION: The connection of a nonshielded 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 Epson America, Inc., could void the user’s
authority to operate this equipment.

For Canadian Users

This digital apparatus does not exceed the Class B limits for radio noise emissions from digital

apparatus as set out in the radio interference regulations of the Canadian Department of
Communications.

Le present appareil numérique n’èmet pas de bruits radioélectrique dépassant les limites
applicables aux appareils numériques de Classe B prescrites dans le règlement sur le brouillage
radioélectriques édicté par le Ministère des Communications du Canada.

LQ-2OO/AP3000

iii

Important Notice

Disclaimer of Warranty

Epson America makes no representations or warranties, either express or implied, by or with
respect to anything in this manual, and shall not be liable for any implied warranties of
merchantability and fitness for a particular purpose or for any indirect, special, or consequential
damages. Some states do not allow exclusion of incidental or consequential damages, of this
exclusion may not apply to you.

Copyright Notice

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 prior written permission of Epson America, Inc. No patent liability is
assumed with respect to use of the information contained herein. While every precaution has been
taken in the preparation of this publication, Epson America assumes no responsibility for errors or
omissions. Neither is any liability assumed for damages resulting from the use of the information
contained herein. Further, this publication and the features described herein are subject to change
without notice.

Trademarks

Epson and ESC/P are registered trademarks of Seiko Epson Corporation.
ActionPrinter is a trademark of Epson America, Inc.

General Notice: Other product names are used herein for identitication purposes only and may be

trademarks of their respective companies.

Copyright © 1991 by Epson America, Inc.

Torrance, CA 90509

iv

LQ-2OO/AP3000

Chapter 1

General Description

Features
Specifications

Parallel Interface
DIP Switches and Jumpers

Operating Instructions

Main Components

...........................................................................................

...................................................................................

Hardware Specifications
Firmware Specifications (ESCYP)

.............................................................................

DIP Switches
Jumpers

SelecType
Self Test
Demonstration

Hexadecimal Dump Function
Bit Image Printing
Error Conditions
Buzzer Operation

Printer Initialization

Default Values

Head Adjust Lever..

Printhead Protection During Heavy Duty Printing..

CO64 MAIN PCB

Control Panel PCB

PEBFIL-II PCB

Transformer

Model 5ClO Printer Mechanism

Housing

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l-l
1-3
l-3
l-9
1-14
1-18
l-18
l-20
1-21

1-21
1-21
l-22
l-23
l-24
1-25
l-25
1-26
l-27
1-28

............... 1-29

l-29
l-30

l-30
1-31

1-31

1-32

1-33

Chapter 2

Overview

Connector Summary
Overview of Printer Mechanism Operation
Circuit Overview
Firmware Overview

Principles of Operation

Power Supply Circuit
Reset Circuit
Address Decoder and Bank Register
Carriage Operation
Paper Feeding
Printhead
A/D Converter Circuit
Host Interface
Ribbon Feed Mechanism

..........................................................................................

...................................................................................

Principles of Operation

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2-l
2-l
2-3
2-7
2-8
2-9
2-9
2-25
2-29
2-30
2-43

2-47
2-52
2-55
2-56

LQ200/AP3000

V

Chapter 3

Disassembly and Assembly

General Repair Information

...........................................................................................

Tools
Small Parts
Service Checklist

Disassembly and Assembly

Removing the Printhead
Removing
Removing
Removing the Printer Mechanism

Disassembling

................................................................................

.......................................................................

the

Case..

the Circuit

the

Chapter 4

Adjustment Overview
Adjusting the Platen Gap
Adjusting

VRl and VR2 Specifications
Adjustment Procedures

the Bidirectional

Chapter 5

............................................................

.............................................................

........................................................... 3-7

..................................................................

Boards..

Printer

Mechanism..

Adjustment

......................................................................

................................................................

Printing Alignment..

.............................................................

Troubleshooting

..................................................

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...................................

..........................

......................................................

3-l
3-2
3-3
3-5
3-6

3-8

3-11
3-14

3-19

4-1

4-1

4-4
4-5
4-6

Procedure for Troubleshooting the Printer
Unit Replacement

Repair

Repair of the Printer Mechanism

of the

Chapter 6

Preventive Maintenance
Lubrication and Adhesive Application

.......................................................................... 5-1

Main Board..

..............................................................

....................................................

Maintenance

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

.....................................

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5-1
5-10

5-17

6-1
6-1

LQ-2OO/AP3000

Appendix

Connector Summary........................................................................

Circuit Diagrams

Circuit Board Component Layout ...................................................

Exploded Diagrams
Case Outline Drawings

Subsequent product modifications will be brought to your attention via Service
Bulletins. Please revise the text as bulletins are received.

This document is subject to change without notice.

Note:

This manual uses minus signs (-) in front of signals to indicate that they
are active LOW signals.

............................................................................. A-3

.......................................................................... A-8

.................................................................... A-12

A-1
A-7

LQ200/AP3000 vii

Chapter 1

General Description

Features
Specifications

Parallel Interface

DIP Switches and Jumpers

Operating Instructions

Main Components

...........................................................................................

...................................................................................

Hardware Specifications
Firmware Specifications (ESCYP)

.............................................................................

DIP Switches

Jumpers

SelecType
Self Test
Demonstration
Hexadecimal Dump Function
Bit Image Printing
Error Conditions
Buzzer

Printer Initialization

Default Values
Head Adjust Lever
Printhead Protection During Heavy Duty Printing..

C064 MAIN PCB
Control Panel PCB
PEBFIL-II PCB
Transformer
Model 5C10 Printer Mechanism

Housing

Operation..

Hardware initialization
Software initialization

..............................................................................

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1-1
1-3

1-3
1-9

1-14

1-18
1-18
1-20
1-21
1-21
1-21
1-22
1-23
1-24
1-25
1-25

1-26
1-26
1-26
1-27
1-28
1-29
1-29

1-30
1-30
1-31
1-31
1-32

1-33

Figures

Figure l-l.
Figure 1-2.

Figure 1-3.
Figure 1-4.
Figure 1-5.
Figure 1-6.
Figure 1-7.
Figure 1-8.
Figure 1-9.
Figure 1-10.
Figure 1-11.
Figure 1-12.
Figure 1-13.
Figure 1-14.

LQ-200/AP3000

LQ-200/AP3000
Pin Configuration
Printable Area for Single Sheet Paper
Printable
Character Matrix
Data Transmission Timing
Self Test
Demonstration
Hexadecimal Dump
Head Adjust Lever
LQ-200/AP3000

C064 MAIN PCB......................................................

Control Panel PCB
PEBFIL-II PCB

....................................................................

.........................................................

.....................................................

....................

Area forContinuous

......................................................

..........................................................

..................................................

....................................................

ComponentLayout..

...................................................

.........................................................

Paper

......................................

......................

.......................

1-2
1-3
1-5
1-6
1-13
1-14
1-21
1-22
1-23
1-28
1-29
1-30
1-30
1-31

Figure 1-15.
Figure 1-16.
Figure 1-17.

Tables

Transformer
Model 5ClO Printer Mechanism

Housing

..............................................................

..............................

.....................................................................

1-31
1-32
1-33

Table 1-1.
Table 1-2.
Table 1-3.
Table 1-4.
Table 1-5.
Table 1-6.

Table 1-7.
Table 1-8.

Table 1-9.
Table 1-10.
Table 1-11.
Table 1-12.

Table 1-13.
Table 1-14.
Table 1-15.
Table 1-16.
Table 1-17.

Table 1-18.

Optional Units
Specifications for
Specifications for
Specifications for Labels

Built-In Fonts

Printing Modes
Character Matrix and Character Size..

..........................................................

Single

Sheet Paper

Continuous Paper..

......................

......................

...........................................

...........................................................

.........................................................

....................

Connector Pin Assignments and

Signal Functions
Handshaking (DCl/DC3) Protocol
DIP Switch Set 1
DIP Switch Set 2

..................................................

............................

......................................................

......................................................

International Character Set and

Character

Table
Font Selection
Page Length

Character Pitch Selection
Print Density

Bit Image Printing

Head Adjust Lever

Selection.. ..................................

...........................................................

Selection

..............................................

........................................

............................................................

...................................................

....................................................

1-2
1-4

1-4
1-4
1-9
1-11
1-12

1-15
1-17
1-18
1-18

1-19

1-19
1-20
1-20

1-24

1-24
1-28

LQ-200/AP3000

General Description

1

Features

The Epson® LQ-200/ActionPrinterTM 3000 (AP3000) is a small, light-weight, low­cost printer similar to the LQ-500. The printer’s main features are:

Epson ESC/P® code printing, implemented as a standard feature
These printing speeds:

Clear, easy-to-read printing with standard Epson fonts
Seven built-in letter quality (LQ) fonts (Roman, Sans Serif, Courier, Prestige,

Script, OCR-B, and Orator)

Direct built-in font selection using control panel buttons

Automatic loading for single sheet paper

Two paper slots (rear and bottom)
Easy handling of single sheet paper with the optional cut sheet feeder (CSF)
Standard Epson 8-bit parallel interface.

192 cps (draft, 12 cpi)
160 cps (draft, 10 cpi)
64 cps (letter quality, 12 cpi)
53 cps (letter quality, 10 cpi)

LQ-200/AP3000

l-l

General Description

Table l-l lists the optional units available for the printer and Figure l-l shows the

printer.

Model

7341

Table 1-1. Optional

Description

Cut sheet feeder (CSF)

Units

Figure 1-1. LQ-200/AP300

1-2

LQ-2OO/AP3000

Specifications

This section provides the specifications for the LQ-200/AP3000.

Hardware Specifications

Printing Method Serial, impact, dot matrix

General Description

Pin Configuration

24 wires; 12 x 2 staggered, diameter 0.008 inches (0.2 mm)

Figure 1-2. Pin Configuration

Feeding Methods Friction feed, tractor feed
Line Spacing 1/6 inch or programmable in units of 1/180 inch
Paper Insertion From rear or bottom
Paper Feed Speed

100 ms/line at 1/6-inch line feed

2.2 inches per second, continuous feed

Paper Specifications See Tables 1-2, 1-3, and 1-4.

LQ-200/AP3000

1-3

General Description

Table 1-2.

Specifications for Single Sheet Paper

Table 1-3. Specifications for Continuous Paper

Table 1-4. Specifications for Labels

1-4

LQ-2OO/AP3O00

Printable Area

General Description

Figure 1-3.

Notes:

0.12 inches (3 mm) or more using 7.2 to 9.0 inch (182 to 229 mm) wide paper.

1)

(27 mm) or more using 10.1 inch (257 mm) wide paper.

.

The lowest print position (0.54 inches or 13.5 mm) is only for reference.

.

Printing is possible approximately 1.48 inches (37 mm) from the bottom edge of the paper when
you press the AUTO LOAD button to load a single sheet.

.

Paper feeding accuracy is not assured within 0.88 inches (22 mm) from the top edge of the
paper and 1.20 inches (30 mm) from the bottom edge of the paper.

Printable Area for Single Sheet Paper

1.08 inches

LQ-200/AP3000

1-5

General Description

Figure 1-4.

Notes:

0.52 inches (13 mm) or more using 4.0 to 9.5 inch (101 to 242 mm) wide paper.

*1)

1.04 inches (26 mm) or more using 10.0 inch (254 mm) wide paper.

0.52 inches (13 mm) or more using 4.0 to 9.5 inch (101 to 242 mm) wide paper.

‘2)

1.04 inches (26 mm) or more using 10.0 inch (254 mm) wide paper.

Printable Area

for

Continuous Paper

1-6

LQ-2OO/AP3000

Ink Ribbon

General Description

Reliability

Type

Black ribbon cartridge #7753

Film ribbon cartridge #7768
Color Black
Life

2 million characters at 48 dots/character

(black ribbon)

0.2 million characters using LQ characters

(film ribbon)

Dimensions
of Ribbon
Cartridge

Mean Cycles
Between
Failure

(MCBF)

Mean Time
Between

Failure

(MTBF)

11.72 inches (width) x 1.36 inches (height)

x

2.88 inches (depth)

(293 mm x 34 mm x 72 mm)

3 million lines (excluding printhead)

40000 power-on hours POH) at 25% duty

Printhead Life

Safety Approvals

200 million strokes (black ribbon)

100 million strokes (film ribbon)

Safety
standards

UL478

Radio
Frequency
Interference
(RFI)

FCC class B

LQ-200/AP3000

1-7

General Description

Electrical Specifications

Power
Conditions

120 VAC * 10%

Frequency
Range

Current
Rating

Power

Consumption mode at 10 cpi)

Insulation
Resistance

Dielectric
Strength

Environmental Conditions

Temperature 41° to

Humidity

Resistance
to Shock

49.5 to 50.5 Hz (50 Hz model)

59.5 to 60.5 Hz (60 Hz model)

1.8 A
Approximately 38 W (during self test in draft

10 megohms minimum between AC line and

chassis

1250 VAC (rms), 1 minute

between AC line and chassis

95’F

(5O to

-22O

to 140°F (-30° to 60°C), in shipping

35OC),

operating

container

10 to 80 % RH, operating
5 to 85 % RH, storage

1 G, within 1 ms, operating
2 G, within 1 ms, storage

Resistance
to Vibration 0.50 G, 55 Hz maximum, storage

Physical Specifications

Weight
Dimensions 15.6 inches (width) x 12.8 inches (depth)

0.25 G, 55 Hz maximum, operating

Approximately 14.1 lb (6.4 kg)

x

5.6 inches (height)
(390 mm x 320 ‘mm x 139 mm)
excluding knob and paper guide

1-8

LQ-200/AP3000

Firmware Specifications (ESC/P)

General Description

Control Codes
Printing Direction

Input Data Buffer

Character Code
Character Sets

Built-In Fonts

ESC/P level ESC/P 84 (Epson Standard Code for Printers)

Bidirectional (text)

Bidirectional (bit image) when DIP switch 2-5 is on

Unidirectional (bit image) when DIP switch 2-5 is off
8KB when DIP switch 2-4 is on

1KB when DIP switch 2-4 is off
(When DIP switch 2-4 is on, you cannot define user-defined
characters.)

8 bits
96-character ASCII character set

14 international character sets
Legal character set

PC (character tables for the Personal Computer) 437, 850,
860,863,865

See Table 1-5.

Table 1-5. Built-h Fonts

Notes:

l o = resident, ‘I = proportional LQ font specified using ESC k, *2 = 15 cpi Courier

l

OCR-B and Orator are basically IO cpi fonts. However, you can select the typestyle and pitch for
these fonts.

l

You cannot select 15 cpi and condensed printing at the same time.

LQ-2OO/AP3000

1-9

General Description

Printing Modes

Printing Speed
Printing Columns

Character Matrix

You can select and mix any of the following printing modes,
except you cannot select 15 cpi and condensed printing at the
same time.

Draft or letter quality printing

l

Character pitch (10 cpi, 12 cpi, 15 cpi, or proportional

l

printing)

l

Condensed

l

Double-width

l

Double-height

l

Emphasized

l

Double-strike

l Italic

l

Underlined

l

Double-underlined

l

Overscore

l

Strike-through

l Outline
l Shadow

See Table 1-6.
See Table 1-6.

See Table 1-7.

Character Size

See Table 1-7.

1-10

LQ-200/AP3000

Table 1-6. Printing Modes

General Description

Notes:

l

Max is the value appropriate for the maximum width character.

l

Min is the value appropriate for the minimum width character.

.

-

means that the printer automatically selects LQ mode when you select proportional pitch.

LQ-200/AP3000

1-11

General Description

Table 1-7.

Character Matrix and Character Size

Notes:

l

HDD is the horizontal dot density in dots per inch.

l

The face matrix and character size indicate the size of the maximum character. This value
depends on the paper, the ribbon, and other variables.

l

Unit ESC SP indicates the minimum length to be added to the right of the character specified using
ESC SP. You can also send Unit Esc SP followed by the character string CHR$ (&h20).

.

-

indicates that printer firmware reshapes the character matrix. Character width is half of the

noncondensed character width.

1-12

LQ-2oo/AP3000

(Normal character)

General Description

LG-200/AP3000

Figure 1-5. Character Matrix

1-13

General Description

Parallel Interface

This section provides the specifications for the standard parallel interface.
Data Format
Synchronization

Handshaking
Signal Level
Adaptable

Connector
Data Transmission

Timing

8-bit parallel

-STROBE signal
BUSY and -ACKNLG signal
TTL compatible

57-30360 (Amphenol) or equivalent

See Figure 1-6.

1-14

Figure 1-6. Data Transmission Timing

LQ-200/AP3000

General Description

Table 1-8 shows the connector pin assignments and signal functions of the 8-bit
parallel interface.

Table 1-8.

Connector Pin Assignments and Signal Functions

LQ-200/AP3000

1-15

General Description

Table 1-9.

Notes:

DIR refers to the direction of signal flow as viewed from the printer.

Connector Pin Assignments and Signal Functions (cont.)

Return Pin No. denotes a twisted pair return line.

The cable must be shielded to prevent noise.

All interface conditions are based on TTL levels. The rise and fall times of all signals must be less
than 0.2 ,us.

You can set the -AUTO FEED-XT signal to LOW using DIP switch 2-4.

You can set the -SLCT-IN signal to LOW using jumper 6.

By setting the DATA 1 through 8 pins to the -STROBE signal, you can perform printing tests,

including interface circuit tests, without using external equipment.

Minus signs are used in front of signal names indicate active LOW signals.

1-16

LQ-200/AP3000

Table 1-9 shows the handshaking (DC1/DC3) protocol.

Table 1-9. Handshaking (DC1/DC3) Protocol

General

Description

Notes:

1.

Table 1-9 assumes that no *ERROR status exists other than that due to off line mode.

2.

When the printer receives a DC3 code, it ignores input data. When the printer receives a DC1
code, data transmission continues.

3.

The DC1 and DC3 codes are enabled only when the SLCT-IN signal (pin number 36) is HIGH and
the printer is initialized.

4.

If the SLCT-IN signal is LOW when the printer is initialized, DC1/DC3 handshaking is invalidated
and the printer ignores the DC1/DC3 control codes.

5.

If the SLCT-IN signal is HIGH when the printer is initialized, the printer starts from the selected
(DC1) state.

6.

Minus signs are used in this table to indicate active LOW signals.

LQ-200/AP3000

1-17

DIP Switches and Jumpers

This section describes the functions of the DIP switches and jumpers.

DIP Switches

The LQ-200/AP3000 has two sets of DIP switches underneath the cartridge slot cover.
Tables 1-10 through 1-15 describe the functions of these DIP switches. The printer reads
the DIP switch settings only at power on or after receiving the -INIT signal.

Table 1-10. Dip Switch Set 1

Notes:

l

1. When DIP switch 2-4 is on, you cannot create user defined characters.

l

2. When DIP switch 2-5 is on, you can select bidirectional graphics printing using ESC UO.

1-18

General Description

Table 1-12. International Character Set and Character Table Selection

Table 1-13. Font Selection

LQ-200/AP3000

1-19

General Description

Table 1-14. Page Length Selection

Table 1-15. Character Pitch Selection

Jumpers

Jumper 6, located underneath the cartridge slot cover, is user selectable. If you
connect jumper 6, the -SLCT-IN signal is LOW and the printer ignores the

DC1/DC3 control codes.

1-20

LQ-200/AP3000

General Description

Operating Instructions

This section explains how to use SelecType, the self test, the demonstration, the
hexadecimal dump, and other functions.

SelecType

The SelecType function allows you to easily choose any of the seven built-in LQ
fonts when the printer is on line and not printing. To select a font, you press the
FORM FEED button until the two SelecType indicator lights match the desired
font.

Self Test

To run the self test in draft mode, turn on the printer while pressing the LINE
FEED button. To run the self test in letter quality (LQ) mode, turn on the printer
while pressing the FORM FEED button.

To stop or start the self test, press the ON LINE button. To end the self test, press
the ON LINE button and then turn off the printer.

The first line of the self test shows the firmware revision number. Next the self
test prints the current DIP switch settings.

Figure 1-7. Self Test

LQ-200/AP3000

1-21

General Description

Demonstration

To start the demonstration, turn on the printer while holding down the LINE
FEED and ON LINE buttons.

THE EPSON® LQ-200

The Epson LQ-200 is the affordable, versatile, narrow carriage 24­pin dot matrix printer
excellent high resolution printing,

for home and small business combining

convenient paper handling, and

a new standard for economical printing.

LOOK AT WHAT THE LQ-200 CAN DO FOR YOU!

n

Outstanding 24-pin print qualitym Sharp180 x 360 DPI graphics.

w

192

CPS

draft print SP'

-” 1.0 Drint

+ional cut sheet feeder

‘;mitaA

.

..-

Figure 1-8. Demonstration

1-22

LQ-200/AP3000

General Description

Hexadecimal Dump Function

You use the hexadecimal dump function to check the data the printer is receiving
from the host. To turn on hexadecimal dump mode, turn on the printer while
holding down the LINE FEED and FORM FEED buttons. In hexadecimal dump
mode, the printer prints the hexadecimal representation of the input data and the
corresponding ASCII characters. If input data is a control code instead of a
character code, the printer prints a period (.) in the ASCII column.

Figure 1-9. Hexadecimal Dump

LQ-200/AP3000 1-23

General Description

Bit Image Printing

The LQ-200/AP3000 has four standard print densities. They are listed below in
dots per inch (dpi), including half dots.

120 dpi at triple speed
180 dpi at double speed
240 dpi at one and a half speed
360 dpi at normal speed

Tables 1-16 and 1-17 show how the firmware handles the print densities.

Table 1-16. Print Density

1-24

Table 1-17. Bit Image Printing

LQ-2OO/AP3000

General Description

Error Conditions

If any of the following error conditions occurs, the printer goes off line.

The printer cannot detect the home position at printer mechanism
initialization.

The printer detects the home position during printing.
You press the ON LINE button when the printer is on line, and the printer

goes off line.
The printer detects a paper-out signal and form over-ride is finished.
A paper-out signal is detected after the printer performs a paper-loading

operation with the cut sheet feeder enabled.

The printer outputs the following interface signals to indicate the error and halt

data transmission:

The BUSY signal becomes HIGH.
The -ERROR signal becomes LOW.
The printer does not send an -ACKNLG pulse.

Buzzer Operation

The buzzer rings when any of the following occurs:

l

The printer receives the BEL code (0.5 second ring).

l

The printer detects a paper-out error (three 0.1 second rings with 0.1 second
intervals).

l

The printer detects abnormal carriage movement (five 0.6 second rings with

0.5 second intervals).

l

The printer accepts a control panel setting (0.1 second ring).

LQ-200/AP3000

1-25

General Description

Printer Initialization

There are two initialization methods: hardware initialization and software

initialization.

Hardware initialization

Hardware initialization takes place when you turn on the printer (and the AC
power cord is plugged in) or when the printer receives the -1NIT signal.

During hardware initialization, the printer:

0

Initializes the printer mechanism.

l

Clears the input data buffer.

l

Clears the downloaded character set.

l

Clears the print buffer.

a

Returns its settings to the default values described on the next page.

Software initialization

Software initialization takes place when the printer receives the software
initialization code. During software initialization, the printer:

l

Clears the print buffer.

l

Returns its settings to the default values described on the next page.

1-26

LQ-2OO/AP3000

General Description

Default Values

When the printer is initialized, the following default values take effect:

Page Position
Left and Right

Margins
Line Spacing
Vertical Tabs
Horizontal Tabs

VFU Channel

Typestyle

User-Defined
Characters

Justification

Character Spacing
Bit Image Mode

Assignment

The current paper position becomes the top-of-form position.

Released

l/6 inch
Cleared
Every 8 characters (relative)
Channel 0
SelecType setting (software initialtiation)

DIP switch setting (hardware initialization)

Deselected (software initialization)

Cleared (hardware initialization)

Left justification

10 cpi

ESCK=ESC*O,ESCL=ESC*l

ESCY=ESC*2,ESCZ=ESC*3

Printing Effects
Condensed

Printing

Clears all effects except for condensed printing.

DIP switch setting

LQ-2OOIAP3000

1-27

General Description

Head Adjust Lever

You must move the head adjust lever to the position appropriate for your paper’s
thickness. See Table 1-18 and Figure 1-10.

Table 1-18. Head Adjust Lever

Note:

If the print density is light, move the head adjust lever one step lower.

1-28

Figure 1-10. Head Adjust Lever

LQ-200/AP3000

General Description

Printhead Protection During Heavy Duty Printing

The printhead is protected from overheating and voltage drops to the printhead

driver. If the printhead temperature exceeds the upper limit, printing stops
automatically until the printhead temperature drops to the required value.

If heavy duty printing causes the printhead driver voltage to drop below the lower
limit, printing stops. When the power supply voltage increases to the required
level, the printer prints the rest of the line.

This protection occurs when half or

more of the wires are activated simultaneously and continuously.

Main Components

The main components are designed so that you can easily remove and replace
them when you maintain or repair the printer. The main components are:

0

C064 MAIN PCB main control board

0

Control Panel PCB control panel board

l

PEBFIL-II PCB filter circuit board

0

Transformer

l

Model 5C10 printer mechanism.

LQ-200/AP3000

Figure 1-11. LQ-200/AP3000 Component Layout

1-29

General Description

C064 MAIN PCB

The µPD7810HG CPU on the CO64 MAIN PCB simplifies the circuit design of the

main control board and controls all of the printer’s main functions.

Figure 1-12.

C064 Main PCB

Control Panel PCB

The control panel PCB is the control panel. It includes the indicator LEDs, the
control panel buttons, and the buzzer.

Figure 1-13.

Control Panel PCB

1-30

LQ-200/AP3000

General Description

PEBFIL-II PCB

The PEBFIL-II PCB filter board eliminates noise from the AC line to the printer
and from the printer to the outer line. The fuse on this board prevents
overheating.

Figure 1-14. PEBFiL-II PCB

Transformer

The transformer converts the input AC from the filter circuit into 28 VAC output
to supply the required voltage to the control circuit board.

LQ-200/AP3000

Figure 1-15.

Transformer

1-31

General Description

Model 5Cl0 Printer Mechanism

The model X10 printer mechanism is designed specifically for the
LQ-200/AP3000. Its components include the carriage motor, carriage mechanism,
paper feed motor, paper feed mechanism, ribbon feed mechanism, printhead, and
sensors.

Figure 1-16. Model 5C10 Printer Mechanism

1-32

LQ-200/AP3000

General Description

Housing

The housing consists of the upper and lower cases. The upper case houses the
control panel. The lower case contains the printer mechanism and the main
control board.

Figure 1-17. Housing

LQ-200/AP3000

1-33

Chapter 2

Principles of Operation

Overview

Connector Summary
Overview of Printer Mechanism Operation

Circuit Overview

Firmware Overview

Principles of Operation

Power Supply

Reset Circuit

Address Decoder and Bank Register

......................................................................................... 2-1

..................................................................

..............................

Sensors
Motors
Printhead

Power supply circuit block diagram
Chopper-type switching regulator circuit
Filter circuit
Transformer
Rectifier and smoothing circuit

+5 VDC regulator circuit

pulse width modulation circuit

+24 VDC regulator circuit

Vx voltage supply circuit

Power on or off

-INIT signal input from CN1
ROM cartridge installation and removal

Address decoder
Bank register

Carriage Operation

Carriage
Carriage motor drive circuit block diagram
Gate array E0lA05 in the carriage motor

Carriage motor drive circuit
Carriage motor software control

Paper Feeding

Paper feed mechanism
Paper feed motor drive circuit
Paper feed motor software control

Printhead

Printing...............................................................................

Printhead drive circuit block
Gate array E05A02 in the printhead

Printhead drive
Printhead software control

A/D Converter Circuit...............................................................

Host Interface............................................................................

Ribbon Feed Mechanism............................................................

.................................................................................

..................................................................................

.............................................................................

........................................................................

...................................................................

....................................................................

Circuit

..............................................................................

mechanism

drive circuit

...........................................................................

...................................................................................

drive circuit....................................................................

.................................................................

....................................

............................

.........................................................................

.........................................................................

...........................................

....................................................

...........................................

..................................................

.....................................................

.....................................................................

..............................................

............................

.........................................

....................................................................

.......................................................................

...................................................................

...........................................................

.......................

....................................................................

................................................

..........................................

........................................................

.............................................

.......................................

circuit

diagram

.........................................................

..................................................

.................................

-

2-1
2-3
2-4
2-6
2-6
2-7
2-8
2-9
2-9

2-9

2-11

2-13
2-14
2-15

2-16

2-19

2-21

2-24

2-25

2-26
2-26
2-27
2-29

2-29

2-29

2-30

2-30

2-31

2-32

2-33

2-38

2-43

2-43

2-45

2-46
2-47
2-47
2-48

2-49
2-50
2-51
2-52
2-55

2-56

LQ-200/AP3000

2-i

Figures

Figure 2-1.
Figure 2-2.
Figure 2-3.
Figure 2-4.
Figure 2-5.
Figure 2-6.
Figure 2-7.
Figure 2-8.
Figure 2-9.
Figure 2-10.
Figure 2-11.
Figure 2-12.

Figure 2-13.
Figure 2-14.
Figure 2-15.
Figure 2-16.
Figure 2-17.
Figure 2-18.
Figure 2-19.
Figure 2-20.
Figure 2-21.
Figure 2-22.
Figure 2-23.
Figure 2-24.
Figure 2-25.
Figure 2-26.
Figure 2-27.

Figure 2-28.
Figure 2-29.

Figure 2-30.

Figure 2-31.
Figure 2-32.
Figure 2-33.
Figure 2-34.
Figure 2-35.
Figure 2-36.
Figure 2-37.
Figure 2-38.
Figure 2-39.
Figure 2-40.

,Figure 2-41.

Figure 2-42.
Figure 2-43.
Figure 2-44.

Figure 2-45.
Figure 246.
Figure 2-47.
Figure 2-48.
Figure 2-49.

Cable Connections
Printer Mechanism Block Diagram..
Paper End Sensor
Home Position Sensor

....................................................

.......................

.....................................................

..............................................

Thermal Sensor........................................................

Printhead.. ................................................................

Circuit Block Diagram
Memory Map (64KB)
Power Supply

Circuit Block Diagram..
Step Down Circuit
Step Down Timing

.............................................

................................................

....................

....................................................

....................................................

PEBFIL-II Filter Circuit Board................................

Transformer Circuit
Rectifier and Smoothing Circuit

.................................................

..............................

+5 VDC Regulator Circuit.......................................

Oscillator Waveform
Constant Voltage Control Circuit

AMP1 Output Control (+5 VDC)

NJM2355 Internal Circuit
Output Transistor Drive Waveform..
+24 VDC Regulator Circuit
Constant Voltage Control

.................................................

............................

.............................

.......................................

.......................

.....................................

(+24 VDC).

.....................

Over-Current Protection ..........................................

Vx Voltage Circuit
Reset Circuit

.............................................................

-RESET Output

...................................................

......................................................

2-2
2-3
2-4
2-5
2-5
2-6
2-7
2-8
2-10
2-11
2-12

2-13
2-14
2-15
2-16
2-17
2-17
2-18
2-19
2-20
2-21
2-22
2-23
2-24
2-25
2-26

-RESET Pulse Oscillation Process
After ROM Cartridge Installation

........................

2-27

-RESET pulse Oscillation Process

After ROM Cartridge Removal .............................

Carriage Mechanism.. ..............................................

Carriage Motor Drive Circuit Block Diagram
Gate Array Operation, 2-2 Phase Excitation..

......... 2-31

.........

Carriage Motor Drive Circuit...................................

STK-6981B Circuit Diagram....................................

Reference Voltage Generation Circuit..

...................

Constant Current Control Circuit ...........................

Chopping Waveforms ...............................................

Schmitt Trigger Circuit............................................

Chopping
Home Position Seek

Current

and Drive Speed..

.................................................

Printing Area and Print Timing

.......................

..............................

Friction Feeding.......................................................

Sprocket Feeding......................................................

Paper Feed Motor Drive Circuit
Paper Feed Motor Drive Timing Chart..

...............................

.................. 2-46

Printing ....................................................................

Printhead Drive Circuit Block Diagram..
Gate

Array E05A02 Block Diagram

................

........................

Printhead Drive Circuit ...........................................

Print Timing

.............................................................

2-28
2-30

2-32

2-33
2-34
2-35

2-36

2-37

2-38

2-40

2-41

2-42

2-43

2-44

2-45

2-47

2-48
2-49
2-50
2-51

2-ii

LQ-200/AP3000

Figure 2-50. Relationship Between the Head Driver Voltage

and the
Figure 2-51. A/D Converter Circuit
Figure 2-52. Host Interface

Print Driving Pulse

..............................................

...........................................................

Figure 2-53. Ribbon Feed Mechanism

Width.......................

..........................................

Tables

2-51
2-53
2-55
2-57

Table 2-1.
Table 2-2.
Table 2-3.
Table 2-4.
Table 2-5.

Table 2-6.
Table 2-7.
Table 2-8.

Table 2-9.

Table 2-10.

Board Connector Summary
Power Supply Applications
Reference Voltages

...................................................

Current Values for Reference

Phase Excitation
Drive
Drive

Sequence
Sequence

.......................................................

(2-2

Phase Excitation) ....................

(1-2

Phase Excitation)

......................................

.......................................

Voltages ...................

Excitation Sequence (Clockwise for

Forward Paper Feeding)

Scan Lines and DIP Switches

Ribbon Feed Gear Train

........................................

...................................

...........................................

....................

2-1
2-10
2-35
2-37

2-38
2-39
2-39

2-46

2-54

2-56

LQ-2OO/AP3000

2-iii

Principles of Operation

2

Overview

This chapter describes the signals at the connectors that link the printer’s primary

components, including the printer mechanism, the power supply circuits, and the
control circuits. This chapter also describes how the printer’s circuitry and the
printer mechanism operate.

Connector Summary

Figure 2-1 shows how the primary components are connected. Table 2-1 lists and
describes the connectors.

Table 2-1. Board Connector Summary

LQ-200/AP3000

2-1

Principles of Operation

Note:

CR = carriage
PF

= paper feed

HP = home position

2-2

Figure 2-1. Cable Connections

LQ-200/AP3000

Principles of Operation

Overview of Printer Mechanism Operation

The model 5ClO printer mechanism is a serial, impact, dot matrix printer
mechanism that prints at 180 dots per inch (dpi) in both the horizontal and
vertical directions. Figure 2-2 is a block diagram of the printer mechanism.

Note:

cw = clockwise
CCW = counterclockwise
HP = home position
PE = paper end

LQ-200/AP3000

Figure 2-2. Printer Mechanism Block Diagram

2-3

Principles of Operation

Sensors

The printer mechanism contains the following sensors:

l

Paper end (PE) sensor

l

Home position (HP) sensor

l

Thermal sensor

Paper end sensor

The paper end sensor switch goes on when the paper runs out. One switch detects
when the paper is out for both the rear and bottom paper slots. Figure 2-3
illustrates the paper end sensor.

Paper out

--t

on + LOW level

Paper present

-+

off + HIGH level

Figure 2-3. Pap End Sensor

2-4

LQ-200/AP3000

Principles of Operation

Home position sensor

The home position sensor switch is on when the carriage is at the home position.
This sensor determines the reference position for the carriage drive. Figure 2-4
illustrates the home position sensor.

+

Home position

on + LOW level

Other position + off + HIGH level

Figure 2-4. Home Position Sensor

Thermal sensor

The thermal sensor in the printhead monitors the printhead’s temperature. If the
temperature exceeds a predetermined upper limit, the printer stops printing until

the temperature drops to a predetermined value. ‘Then printing resumes. Figure
2-5 illustrates the thermal sensor circuit.

LQ-200/AP3000

Figure 2-5. Thermal Sensor

2-5

Motors

The LQ-200/AP3000 has the following motors:

l

Carriage motor (stepper motor)

l

Paper feed motor (stepper motor)

Carriage motor

The carriage motor moves the carriage right and left along the platen. It is a four­phase, 48-step motor that uses either 1-2 or 2-2 phase excitation. An open loop
system controls the carriage motor.

Paper feed motor

A four-phase, 48-step motor feeds paper. It advances the paper 1/180th of an inch
for each step (phase switch), using 2-2 phase excitation. The CPU controls the
paper feed motor under an open loop configuration.

Printhead
Figure 2-6 illustrates dot wire operation. The head driving coil energizes and this

drives the dot wire outward. The dot wire strikes the ribbon against the paper,
printing a dot.

2-6

Figure 2-6. Printhead

LQ-200/AP3000

Circuit Overview

Figure 2-7 is a block diagram of the printer’s circuitry.

Principles of Operation

Note:

CG = character generator
GA = gate array

LQ-200/AP3000

Figure 2-7.

Circuit Block Diagram

2-7

Principles of Operation

Firmware Overview

The printer uses a µPD7810HG CPU with 64KB of address space. Figure 2-8

shows a memory map of the address space.

Note:

CG = character generator
GA = gate array

2-8

Figure 2-8. Memory Map (64 KB.)

LQ-200/AP3000

Principles of Operation

Principles of Operation

This section describes the operation of the printer’s components, including the
power supply circuit, the reset circuit, the carriage mechanism, the paper feed

mechanism, and the printhead.

Power Supply Circuit

This section describes how the power supply circuit operates.

Power supply circuit block

diagram

120 VAC is applied through the filter circuit to the step down transformer, which
generates 26 VAC. The 26 VAC is input to the power supply circuit on the main
board.

The 26 VAC is converted into approximately 36 VDC via the full wave rectifier
and smoothing circuit. The 36 VDC is input to the regulator circuits, which
supply +24 and +5 VDC to the control circuit. The +24 and +5 VDC are also
supplied to the Vx voltage circuit. The Vx voltage circuit is applied to the control
circuit.

LQ-2OO/AP3000 2-9

Principles

of

Operation

Figure 2-9. Power Supply Circuit Block Diagram

Table 2-2. Power Supply Applications

2-10

LQ-2OO/AP3000

Principles of Operation

Chopper-type switching regulator circuit

The power supply circuit includes a chopper-type switching regulator. The step
down circuit operates as follows:

Figure 2-10. Step Down Circuit

Figure 2-10 shows the chopper-type step down switching regulator circuit. When
the transistor is on, voltage Vi is applied to coil L and capacitor C. Load current I1
flows and electromagnetic energy Wl accumulates in choke coil L. When the
transistor goes off, energy Wl is applied to the load via flywheel diode D.
Therefore, output voltage Vo is the average value:

LQ-200/AP3000

2-11

Principles of Operation

Thus, Vo can be held constant by controlling Ton. Figure 2-11 shows the step
down timing.

Figure 2-11. Step Down Timing

2-12

LQ2OO/AP3000

Principles of Operation

Filter circuit

The AC line voltage passes through the power switch and is input to the filter
circuit. The PEBFIL-II board includes a fuse, Fl. The filter circuit attenuates

external noise and inhibits the noise generated in the printer from propagating
through the AC line. Cl or C2 drains leakage current between the primary coil

and the case. Figure 2-12 shows the filter circuit.

Figure 2-12.

PEBFIL-II Filter Circuit Board

2-13

Principles of Operation

Transformer

The 120

VAC

that passes through the filter circuit is transformed into 26

VAC

and supplied to the main board. Figure 2-13 is a schematic drawing of the power

transformer.

2-14

LQ-200/AP3000

Principles of Operation

Rectifier and smoothing circuit

Diode bridge DB1 full wave rectifies the 26 VAC from the transformer’s secondary

coil. Then smoothing capacitor C40 converts the 26 VAC into approximately

36 VDC. The +24 and +5 VDC voltages are converted from this DC voltage. The

DC voltage is used as the power supply voltage for the switching regulator circuit
at the next stage.

Figure 2-14. Rectifier and Smoothing Circuit

LQ-200/AP3000

2-15

Principles of Operation

+5 VDC regulator circuit

An NJM2355 switching regulator circuit is used for constant-frequency pulse
width modulation. The rectifier and smoothing circuit employs an NJM2355
circuit configured as a chopper-type switching regulator circuit. Figure 2-15

illustrates the +5 VDC regulator circuit.

2-16

Figure2-15. +5 KDC Regulator Circuit

LQ200/AP3000

Principles of Operation

The +5 VDC regulator circuit has a built-in oscillator. External components
connected to pins 2 and 3 determine the oscillation frequency. R105 and C34

cause the circuit to oscillate at about 30 KHz. Figure 2-16 shows the oscillator
waveform.

Figure 2-16. Oscillator Waveform

AMP1 in the +5 VDC regulator circuit is an error amplifier that monitors the
output voltage. Figure 2-17 shows the constant voltage control circuit. Pin 1 of
the +5 VDC regulator circuit provides a 5 V reference output (Vref). Vref is
applied to the negative terminal of AMP1. The error amplifier adjusts its output
according to the voltages at its positive and negative input terminals. This keeps
the positive terminal voltage at 5 V.

LQ-200/AP3000

Figure 2-17.

Constant Voltage Control Circuit

2-17

Principles of Operation

Figure 2-18 shows the output from AMP1. When the voltage at pin 4 becomes
higher than that at pin 5 (over-voltage), pulse width modulation modulates the
AMP1 output current and reduces the circuit’s output voltage. R108 and C35
compensate for phase lag in the error amplifier, preventing abnormal oscillation.
(The next section describes pulse width modulation.)

Figure 2-18. AMP1 Output Control (+5 KVC)

LQ-2OO/AP3OOO

Principles of Operation

Pulse width modulation circuit

This section describes how the pulse width modulation (PWM) comparator
operates. Figure 2-19 shows the internal circuitry of the NJM2355 integrated
circuit.

In circuit 1, the output from AMP1 flows into the negative terminal of PWM

comparator 1. In circuit 2, the outputs from AMP2 and AMP3 flow into the
negative terminal of PWM comparator 2 without wired OR. The dead-time control
voltage is input to additional negative terminals of both comparators. At the same
time, a saw-tooth waveform from the oscillator is input to the positive terminals.
The saw-tooth waveform causes the comparators to generate pulses as shown in
Figure 2-20.

LQ-200/AP3000

Figure 2-19. NJM2355 Internal Circuit

2-19

Principles of Operation

As shown in Figure 2-20, the dead-time control voltage controls the potential at
the NJM2355 circuit when it is lower than the preset voltage or current value.
When it exceeds the preset voltage, the error amplifier lowers it below the preset

voltage.

Figure

2-20.

Output Transistor Drive Waveform

2-20

LQ-200/AP3000

Principles of Operation

+24 VDC regulator circuit

The +24 VDC regulator circuit has approximately the same function and employs
the same oscillation circuit as the +5 VDC regulator circuit. In the +24 VDC
regulator circuit, error amplifier AMP2 is used for over-current control and AMP3

is used for constant voltage control. Figure 2-21 shows the +24 VDC regulator
circuit.

Figure 2-21. +24 VDC Regulator Circuit

LQ-200/AP3000

2-21

Principles of Operation

Error amplifier AMP3 operates as follows. The negative terminal of AMP 3
receives Vref (5 V) and the voltage applied to the positive terminal is adjusted to
5 V. As shown in Figure 2-22, the output voltage is:

2 4z

~(Rl14+R115)

=

Jhms (9.1 K ohms +

2.4K

ohms) = 23.96 V

Figure 2-22. Constant Voltage Control (+24 KDC)

AMP 2 controls over current as follows.

+24 V is applied to the negative terminal.
The positive terminal receives an equal voltage when a negative current of the
following value flows:

OutPit ylltage R 124/Rl27 =

+24 ’

11K ohms

560 ohms / 0.22 ohms

=5.55

A

2-22

LQ-200/AP3000

Principles of Operation

If the current exceeds this value, over-current protection goes on to reduce the
output voltage. Figure 2-23 illustrates over-current protection. Because pin 3 of
IC1 is grounded, dead time does not apply in this case.

Figure 2-23.

Over-Current Protection

LQ200/AP3000

2-23

Principles of Operation

Vx voltage supply circuit

When the +24 V power supply line reaches 18.6 V (18 V + 0.6 V), transistors Q25
and Q26 go on and Vx (+5 v) is output. If the +24 V power supply line drops

below 18.6 V, Q25 and Q26 go off and the Vx voltage is extinguished.

The Vx voltage prevents abnormal operation when you turn the printer on or off.
When you turn the printer on or off:

l

The Vx voltage circuitry is reset and does not drive the printer until the power
supply stabilizes.

l

Full-ups for the printhead signal lines prevent printhead malfunctions.

l

Pull-ups for the paper feed motor signal lines prevent paper feed motor

malfunctions.

2-24

Figure 2-24. Vx Voltage Circuit

LQ-200/AP3000

Principles of Operation

Reset Circuit

The reset circuit sends the -RESET signal to the -RESET terminal of CPU
µPD7810HG (4B). The -RESET signal acts as a hardware initialization signal.
Figure 2-25 shows the reset circuit.

The reset circuit outputs the -RESET signal when any of the following occur:

l

You turn the printer on or off.

0

The host interface or an optional interface inputs the -INIT signal.

LQ-200/AP3000

Figure 2-25. Reset Circuit

2-25

Principles of Operation

Power on or off

D14, R69, and C26, shown in Figure 2-25, comprise an on/off reset circuit. This
circuit causes the CPU to begin operation from address 0000H when you turn on
the, power and it prevents CPU malfunctions when you turn off the power.

The rising edge of the Vx voltage cancels the -RESET signal following a constant­time delay (R69 x C26) produced by the gate array, resistor R69, and capacitor
C26. The falling edge of the Vx voltage activates the -RESET signal by

discharging capacitor C26 via diode D14.

Gate array pins 49 to 51 are used for waveform shaping.

Figure 2-26.

-RESET Output

-INIT signal input from CN1

The external -INIT signal (50 psec or more) passes through the low-pass filter by
R31 and C22. The signal is wave shaped within the gate array (pin 47, ICGC) so
that the -DISC terminal is set to LOW. This causes capacitor C26 to discharge,
setting the -THLD terminal to LOW. Then the -Rout terminal outputs the

-RESET signal.

2-26 LQ-2OO/AP3000

Principles of Operation

ROM cartridge installation and removal

Figure 2-27 shows the -RESET pulse generation process after you install a ROM
cartridge. A LOW signal flows into the -CAR terminal of the gate array (6C, the

-DISC terminal (1) outputs a LOW signal, and the -Rout terminal (2) outputs a

-RESET signal.
As the -DISC terminal goes LOW, capacitor C26 discharges at a time constant of

R70 x C26 (3). When the C26 discharge reduces the potential at the -THLD
terminal to the threshold voltage Vth, the -RESET signal is canceled (4) and the

-DISC terminal goes HIGH (5). After the -DISC terminal goes HIGH, the Vx

voltage again discharges C31 at a time constant of R69 x C26 (6).

LQ-200/AP3000

Figure 2-27.

After ROM Cartridge Installation

-RESET Pulse Oscillation Process

2-27

Principles of Operation

Figure 2-28 shows the -RESET pulse oscillation process after you remove a ROM
cartridge. The -CAR terminal of the gate array (6C) receives a HIGH signal, the

-DISC terminal outputs a LOW signal (1), and the -Rout terminal outputs a

-RESET signal (2).

The rest of the process is similar to what occurs after ROM

cartridge installation. See the description above.

2-28

Figure 2-28.

After ROM Cartridge Removal

-RESET Pulse Oscillation Process

LQ-200/AP3000

Principles of Operation

Address Decoder and Bank Register

This section describes the address decoder and bank register.

Address decoder

The address decoder in gate array E01A05 (6C) outputs a chip select signal to the

internal PROM (3C), 4MCG (5C), 1MCG (2C), RAM (2C), and HEAD gate array

(7A) via address lines AB12 through AB15 and bank lines 7 and 6 in the gate

array.
The chip select for -CS is generated with the -RD signal and the chip select for

the RAM is generated with the -ALE signal.

Bank register

The printer has a bank register in gate array E0lA05 (6C). The bank lines are set
by writing to address F002H and can be checked by reading the same address.

LQ-200/AP3000

2-29

Principles of Operation

Carriage Operation

This section describes the carriage.

Carriage mechanism

The carriage mechanism includes the printhead, the carriage, the timing belt, the

carriage motor, and the platen. Figure 2-29 shows the carriage mechanism.
The timing belt is connected to the bottom of the carriage.

It is driven by the
carriage motor and moved via the belt-driven pulley. The printhead is mounted on
the carriage. The entire unit moves right and left along the guide shaft and guide
plate.

2-30

Figure 2-29. Carriage Mechanism

LQ-200/AP3000

Principles of Operation

Carriage motor specifications

4-phase, 48pole stepper motor

24 V

f

Drive Voltage
Coil Resistance
Current

21 ohms f 7% at 77O F

0.34 A, maximum (rush current)
Driving:

10%

(25’ C)

0.3 A, typical (triple speed, 24

VI

0.23 A, typical (double speed, 1.5 speed,

Holding:

normal speed, 24

0.17 A f 20%

VI

Carriage motor drive circuit block diagram

Figure 2-30 is a block diagram of the carriage motor drive circuit. The CPU does
not directly execute phase switching for the carriage motor. Instead, gate array

6C generates the phase switching based on CPU-generated pulses. The
STK-6981B circuit stabilizes the drive current.

LQ-200/AP3000

Figure 2-30.

Carriage Motor Drive Circuit Block Diagram

2-31

Principles of Operation

Gate array E0lA05 in the carriage motor drive circuit

Gate array E0lA05 (6C) implements phase switching for the carriage motor, which
is a stepper motor. The gate array first sets the excitation type (2-2 or 1-2 phase)
and rotation direction (clockwise or counterclockwise). When the CPU outputs a
pulse to the gate array’s TM terminal, the gate array executes auto phase
switching, which drives the stepper motor. Figure 2-31 shows this process.

Figure 2-31.

Gate Array Operation, 2-2 Phase Excitation

2-32

LQ-2OO/AP3000

Principles of Operation

Carriage motor drive circuit

The LQ-200/AP3000 includes an STK-6981B, a hybrid integrated circuit used to
drive stepper motors. The STK-6981B (ICSC) circuit drives the stepper motor
under a constant current.

An external voltage level determines the value of the
current. STK-6981B operation is divided into equivalent phases AB and CD. This
section describes phase CD. Figure 2-32 shows the carriage motor drive circuit.
Figure 2-33 shows the STK-6981B circuit diagram.

LQ2OO/AP3000

Figure 2-32.

Carriage Motor Drive Circuit

2-33

Principles of Operation

Figure 2-33. STK-6981B Circuit Diagram

Note:

Phase AB is equivalent to phase CD, which is shown in the figure above.

2-34

LQ-200/AP3000

Principles of Operation

Reference voltage generation circuit

Figure 2-34 shows the reference voltage generation circuit. Table 2-3 shows the
reference voltages.

Figure 2-34. Reference Voltage Generation Circuit

Table 2-3. Reference Voltages

1

L

1

H 1 0.736 V

LQ-200/AP3000

2-35

Principles

of

Operation

Constant current drive circuit

The carriage motor drive current is given by the following equation:

When the carriage stops, CPU port PB5 is set to HIGH, the input to the chopping
circuit becomes 0 V, and current is applied from the +5 V line to the motor via
resistance Rl and diode Dl. This current is given by the following equation:

Figure 2-35 shows the constant current control circuit. Table 2-4 lists the current
values for the reference voltages.

2-36

Figure 2-35. Constant Current Control Circuit

LQ-200/AP3000

Principles of Operation

Table 2-4.

Current Values for Reference Voltages

Positive feedback through R9 generates a hysteresis in the comparator of ICl.
The upper limit of the hysteresis is the reference voltage. The comparator works
like a Schmitt trigger, sensing a difference when the inverse terminal feedback is
slightly larger or smaller than the hysteresis level. The comparator in ICl
compares reference voltage a! and the feedback voltage.

When reference voltage (Y is HIGH, TR6 goes on and applies approximately

25 VDC to the coil. The current rises linearly due to inductance. TR6 goes off
when the feedback voltage equals the reference voltage. In this way, an almost
constant current is applied to the coil.

Figure 2-36 shows the carriage motor’s drive current waveform (pin 12) and the
chopping waveform (pin 17) of the drive voltage (+24 v) at 960 pps. Figure 2-37

shows the Schmitt trigger circuit.

Figure 2-36. Chopping Waveforms

LQ200/AP3000

2-37

Principles of Operation

Figure 2-37. Schmitt Trigger Circuit

Carriage motor software control

This section describes the carriage motor software control.

Excitation type

Firmware determines the excitation. As shown in Table 2-5, the excitation is
executed according to the carriage speed. Tables 2-6 and 2-7 show the motor drive

sequence for each excitation system.

Table 2-5. Phase Excitation

2-38

LQ-200/AP3000

Principles of Operation

Table 2-6. Drive Sequence 2-2 Phase Excitation)

Table 2-7. Drive Sequence

(l-2

Phase Excitation)

2-39

Principles of Operation

The stepper that controls the carriage can hold the carriage at any position and
freely switch its direction. An open loop system controls the carriage motor and

switches the phase according to the set speed.

The drive chopping current is switched at the carriage motor drive frequency.
Figure 2-38 shows the relationship between drive speeds and switching current
values.

Figure 2-38.

Chopping Current and Drive Speed

2-40

LQ-200/AP3ooo

Principles of Operation

Home position seek

The home position seek function causes the carriage to move to the home position
when the power goes on. Figure 2-39 shows how the home position seek function

operates.

When power is first applied, the printer executes 2-2 phase excitation for 20 or 30

ms (regardless of the phase switch setting). Meanwhile, the printer checks the

-HOME signal to determine whether the starting position is 1 or 2.

The carriage enters the home position only once during the initialization.

LQ-200/AP3000

Figure 2-39 Home Position Seek

2-41

Principles of Operation

Printing area

The printing area starts 22 phase switches from the home position.

Figure 2-40. Printing Area and Print Timing

Abnormal carriage operation

The LQ-200/AP3000 does not have a print timing signal PTS) sensor and cannot
detect abnormal carriage operation. Therefore, an error does not occur if external
forces hinder carriage movement.

An error occurs only if the printer receives the

-HOME signal in the printing area. If this occurs, the carriage stops.

2-42

LQ2OO/AP3000

Principles of Operation

Paper Feeding

This section describes how the printer feeds paper.

Paper feed mechanism

The LQ-200/AP3000 friction feeds single sheet paper and sprocket feeds continuous
paper.

The printer

cover

and the spring force of the two paper feed rollers hold the paper

against the platen. To release the paper, move the paper release lever forward.

Friction feeding

The paper feed motor rotates the platen gear, via the paper feed reduction gear, in
the direction shown in Figure 2-41. Friction from the platen and paper feed rollers

feeds the paper in the direction shown in Figure 2-41.

LQ-200/AP3000

Figure 2-41. Friction Feeding

2-43

Principles of Operation

Sprocket feeding

You place the holes in the paper over the sprocket pins on the sprocket wheel. The
paper feed motor rotates the gears, via the pinion on the shaft of the motor, in the
direction shown in Figure 2-42. The gear rotation causes the sprocket wheels to

rotate and advances the paper in the direction shown in Figure 2-42.

2-44

Figure 2-42. Sprocket Feeding

LQ-2OO/AP3000

Principles of Operation

Paper feed motor specifications

4-phase, 48pole stepper motor

24

Drive Voltage
Coil Resistance
Phase Excitation
Current

Driving Frequency

VDC + 10%
58 ohms f 7% at 77O F (25O C)
2-2 phase excitation

1.1 A, maximum (rush current)

0.30

Driving:
Holding:

400

pulses per second

A, typical

0.06 A 5 20

mA

Paper feed motor drive circuit

Figure 2-43 shows the paper feed motor drive circuit. When the paper feed signal

PB2

goes LOW,

Q27

goes on and supplies +24 V to the motor. When the paper
feed motor is not being driven (when it is in hold status), +5 V is supplied to the
motor via resistor R36 and diode Dll.

LC&200/AP3000

Figure 2-43. Paper Feed Motor Drive Circuit

2-45

Principles of Operation

Paper feed motor software control

The paper feed motor is a 48-pole stepper motor. An open loop system controls the
paper feed motor under 2-2 phase excitation. The motor feeds paper 1/180th of an
inch for each step.

Table 2-8 shows the paper feed motor excitation system when

the motor is driven clockwise for forward paper feeding.

Excitation Sequence (Clockwise for Forward Paper Feeding)

Note:

Table 2-8.

If the paper feed motor is driven counterclockwise, it feeds paper backward.

Figure 2-44 shows the timing chart for acceleration and deceleration control.

2-46

figure 2-44. Paper Feed Motor Drive Timing Chart

LQ-200/AP3000

Principles of Operation

Printhead

This section describes how the printhead operates.

Printing

This section describes how a dot wire prints. Figure 2-45 illustrates the printing
operation. When the printing process begins, the actuating plate is engaged to the
dot wire. When the dot wire’s head driving coil is energized, the actuating plate is
attracted to the iron core. This drives the dot wire toward the platen. The dot
wire strikes the ribbon and the paper against the platen, printing a dot.

When the head driving coil de-energizes, the actuating plate spring returns the
plate

to

its initial position. At, the same time, the impact of printing the dot and
the effect, of the wire resetting spring returns the dot wire to its initial position.
The dot wire remains engaged to the actuating plate until it is driven again.

LQ-200/AP3000

Figure 2-45. Printing

2-47

Principles of Operation

Printhead specifications

Solenoids

Wire Diameter

Pin Arrangement
Drive Voltage
Coil Resistance

24 solenoids

0.008

inch (0.20 mm)

12 x 2, staggered

24

VDC f

10%

19.1 k 1.0 ohms at

77O

F

(25O C)

Printhead drive circuit block diagram

Gate array E05A02 is used as an 8-bit x 3 data latch. By monitoring the
printhead drive power (+24 V line), the CPU determines the pulse width for the
head wire drive pulses from gate array E05A02. The CPU also monitors the
printhead’s temperature and suspends printing.if the printhead overheats.

2-48

Figure 2-46. Printhead Drive Circuit Block Diagram

LQ-200/AP3000

Principles of Operation

Gate array E05A02 in the printhead drive circuit

The E05A02 gate array includes circuitry to interface the CPU and the printhead.
This general purpose gate array has special commands that lighten the CPU’s load

during printhead data output.
Figure 2-47 is a block diagram of gate array E05A02.

Gate array operation centers
around the three 8-bit data latches. The gate array also supports functions
(commands) that can efficiently write data to any of the data latch bits.

Figure 2-47.

Gate Array E05A02 Block Diagram

2-49

Principles of Operation

Printhead drive circuit

CPU port PC6 adjusts the drive pulse width. The Vx voltage pulls up the output
signals from the gate array to prevent printhead malfunctions.

Figure 2-48. Printhead Drive Circuit

2-50

LQ-200/AP3000

Principles of Operation

Printhead software control

At 960 pps, one print cycle is performed at each phase switch step to meet the
printhead’s specifications. (The printhead’s solenoid drive frequency is 960 Hz).
The drive pulse width is adjusted using an A/D converter to detect the drive
voltage. The drive pulse width is kept within the range indicated by the oblique
lines in Figure 2-50.

Figure 2-49. Print Timing

Drive Voltage(V)

LQ-200/AP3000

Figure 2-50.

Relationship Between the Head Driver Voltage
and the Print Driving Pulse Width

2-51

Principles of Operation

A/D Converter Circuit

Figure 2-51 shows the A/D converter circuit. The converter has the following
functions:

l

Monitors the +24 V line to determine the drive pulse width for the printhead.

l

Monitors the temperature (the resistance) of the printhead.

l

Reads the initial DIP switch settings.

l

Reads the bidirectional adjustment setting.

Shunt regulator TL431CLPB and resistors R37 and R55 regulate reference voltage
Vref as follows:

Vref =

g

(R55+R37)

= 4.5 V

Note: The shunt regulator’s reference voltage is 2.5 V.
Using this value as a reference, AN0 monitors the +24 V line, AN1 monitors the

printhead temperature, and AN2 through AN7 read the DIP switch and
bidirectional adjustment settings.

2-52

LQ-200/AP3000

Principles of Operation

LQ200/AP3000

Figure 2-51. A/D Converter Circuit

2-53

Principles of Operation

Table 2-9 shows the relationship between the scan lines and the DIP switches.

2-54

LQ-2OO/AP3000

Host Interface

Principles of Operation

Figure 2-52 shows the host interface circuit.

-STROBE pulses from the host

computer pass through the low-pass filter formed by R32 and C21 and then flow

into the -STRB terminal. These pulses latch the parallel data and set the BUSY
signal HIGH, inhibiting subsequent data transfer. The -STROBE signal
automatically outputs the gate array’s -PINT terminal to request a CPU
interrupt. When the CPU receives the interrupt request, it reads the data latched
in the gate array.

LQ-200/AP3000

Figure 2-52. Host Interface

2-55

Principles of Operation

Ribbon Feed Mechanism

The ribbon feed mechanism consists of the ribbon cartridge and the ribbon feed

section. Table 2-10 describes the ribbon feed gear train. Regardless of the timing

belt direction, the gear train setup assures that the ribbon driving gear rotates

only counterclockwise.

Table 2-10. Ribbon Feed Gear Train

Figure 2-53 shows the ribbon feed mechanism. The ink ribbon is an endless loop
partly contained in the cartridge case. It is held between the ribbon feed and
ribbon pressure rollers mounted on the ribbon driving gear. The gear’s movement

drives these rollers, which in turn feed the ribbon.

To prevent ribbon slack, a ribbon braking spring is attached at the cartridge case
exit.

A ribbon mask prevents the ribbon from staining the paper.

2-56

LQ-2OO/AP3000