Star NX-1001, LC-20 Technical Manual

DOT MATRIX PRINTER

NX-1001

LC-20

TECHNICAL MANUAL

[ SIXTH EDITION ]

NOTICE

• All rights reserved. Reproduction of any part of this manual in any

form whatsoever, without STAR’s express permission is forbid­den.

• The contents of this manual are subject to change without notice.

• All efforts have been made to ensure the accuracy of the contents

of this manual at the time of going to press. However, should any
errors be detected, STAR would greatly appreciate being in­formed of them.

• The above notwithstanding, STAR can assume no responsibility

for any errors in this manual.

© Copyright 1990-1997 Star Micronics Co.,Ltd.

INTRODUCTION

This manual is an introduction to dot matrix printers as shown below.
It is intended for use as a reference for periodic inspections and maintenance procedures.
This manual is prepared for use at a technical level and not for the general user.

1

Model Destination

NX1001 MULTI-FONT For American, Asian, and Russian market
LC-20 For European and Pacific market

This manual is divided into the following sections:

•

Chapter 1 General Specifications
Chapter 2 Theory of Operation
Chapter 3 Adjustments
Chapter 4 Parts Replacement
Chapter 5 Maintenance and Lubrication
Chapter 6 Troubleshooting
Chapter 7 Parts List

First edition : Jul. 1990

•

Second edition : Feb. 1991
Third edition : Mar.1993
Fourth edition : Aug.1994
Fifth edition : Aug.1996
Sixth edition : Aug.1997

2
3
4
5
6
7

(Blank Page)

C 1

Se

Si

G S

1.

GeneralSpecifications

2. ExternaiAppearanceandComposition

2 N o P
2

2 CoP Co. . . . . . . . . . . . . . . . . . . . . . . . . ...

3.

3 GeSpe. . . . . . . . m..m..

3 Con. . . . . . . . . . u-.-..

4 Ser(o

4
4 Co

D S

Paraiieiinterface

GeSpe

DiSe

4

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

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

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

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

. - . ----

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

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

a FuDe...

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

3

5
5

8

9
9

10

I

GENERAL SPECIFICATIONS

1. General Specifications

Pr

Printingmethod
Piintingspeed

Databuffer

Paperfeed

Printingdirection

Characterset

Standardcharacterset
IBMcharacterset
Downloadablecharacters
Internationalcharactersets”’

Dotmatrixsize

Charactermatrix

Normal

Double
High-speeddouble
Quadruple
CRTI
CRTII
Plotter

Double-plotter
Linespacing
Columnwidth

InthecaseofRussianversion,theinternationalcharactersetsareehmmated.

*1

Serialimpactdotmatrix

150characterspersecond(in Draft pica)

37.5charactersper second(inNLQpica)
4Kbyteswhennotusedfordownloadcharacters

l-Linebufferwhenusingdownload

2.8inches/second(duringpagefeed)
Frictionandpush-tractorfeed

Draft:bi-directionalor unidirrxxional(selectable),logicseeking
NLQandgraphics:unidirectional,logicseeking

96ASCIIcharacter
244characters(ASCII,internationalcharacters,symbols,blockgraphics)
Max.192(draft)or74(NLQ)

14sets(USA,France,Germany,England,DcnmarkI,DenmarkII,Sweden,Italy

SpainI, SpainII,Japan,Norway,LatinAmerica,Denmark/Norway)

9 x 11(Draft)

18X23(NLQ)

DPI
(8or9) x480 60
(8or9) x960 120
(8or9) x960 120
(8or9) x 1920 240
(8or9) x640 80
(8or9)x 720 90
(80r9) x576 7
(8or9) x 1152 144

1/6inchstandard

80,normalpica

137,condensedpica

1/8,nf72,orn/216inchprogrammable

96,normalelite

160,condensedelite

.. . .

P

Singlesheets

Fanfoldpaper

5.5- 8.5incheswide 0.07-0.10 mmthick

4-10 incheswide 0.07-0.10 mmthick(single-ply)
Max,0.28mmthick(3-ply)

-3-

GENERAL SPECIFICATIONS

Pr

Dimensions

Weight
Power

Powerconsumption
Environment

Print head

Ribbon

Option

Pain

Interface
Synchronization
Handshaking
Logiclevel
Connector I 57-30360Am~henol

Height120mm(4.7inches)
Depth301mm(11.8inches)

5.1kg (11.2pounds)
120VAC*1O%,60 Hz.

240VAC+1O’%,50/60Hz.
Typ.36W.Max.80W
Operatingtemperature:5 to 40”C(41to I04”F)

Operatinghumidity:10to 80%,noncondensation
Storagetemperature:–30to 65°C(-22 to 149°F)
Storagehumidity:10%to 95%(at40°C)(nocondensation)

9 pins
Life:100milliondots

Fabricribboncartridge
Life:1milliondraftcharacters

Automaticsheetfeeder
Serial-Parallelconverter(SPC-8K)

Centronics-compatible
Byexternalsuppliedstrobepulses
ByACKor BUSYsignals

Width396mm(15.6inches)

220VAC+1O%,50/60Hz.

%

I

I

Fig. 1-1ExternalDimensions

–4-

I

“a’enK

GENERAL SPECIFICATIONS

External Appearance and Composition

2.

N P

2

P C

R C

B L

/ L

‘ C

Fig. 1-2FrontViewofthePrinter

P M

-

I C

a L

Fig.1-3DiagramofInternalComposition

-5-

GENERAL SPECIFICATIONS

2 S S

\

/

I

1

Fig. 1-4TheDIPSwitchesarelocatedunderthePrinterCover

1) ExceptforRussianversion

Switch

1-1

Function

Printermode

ON OFF

Standard IBM

I 1-2 I Usageof RAM I Buffer

1-3
1-4
1-5

\ 1-6 I Oratorlowercase

1-7
1-8

k

1

AutoLF

No Yes
Autosheetfeeder Inactive
Pawr-outdetector

Enabled Disabled

I Smallcam I Lowercase

Pagelength

1

(See right)

Characterset

2-1

Characterset

(Standardmode) ‘raphics ‘wlics

(IBMmode) ‘et#2

2-2

2-3

Internationalcharacterset(Seeright)

2-4

D S 1

I Download

Active

Set#1

/

D S 2

O

P l

Inc s

Country

U.S.A.
France
Germany
England
DenmarkI*
Sweden
Italy
SpainI

Denmark/Norwaywhenswitc2-1is ON.

*

2 2

ON ON ON

OFF ON ON

ON OFF ON

OFF OFF ON

ON ON

OFF

ON

OFF OFF

ON

OFF OFF

2

OFF
OFF

OFF

2) ForRussianversion

I Switch \

Function

I 1-1 I Printermode

1-2

1-3

I-4

UsageofRAM Buffer Download
AutoLF No Yes
Autosheetfeeder Inactive Active

I 1-5 I Parer-outdetector

14

Character/Command

1-7

PageLength 11inches 12inches
Characterset Set#1 Set#2

Codepage

t---i

1-8
2-1
2-2
2-3

I 2-4 I Notused

ON

I

\ OFF

I Standard I IBM I

I Enabled I Disabled \

(Seeright)

(See right)

I I

-

Ch

I

( s 1 i o

Character/Command

Italiccancel
Italicselect
MSBnotcontrol
MSB=l

1-6

ON

OFF

ON

OFF

1-7

ON

ON
OFF
OFF

C p

Codepage

‘ R 1%---wl

#3840IBM-Russian
Gost

2-2

1

OFF

I OFF / OFF

2-3

I

ON

I

2

1)

2)

Atoffline

H

tl

Hold
Push

S p f

S p p

Agingmode

R m

Forwardm

F

w

*1 In thecaseof Russianversion,“ORATOR”fontis eliminated.

–7–

G SPECIFICATIONS

3. Parallel interface

3-1.GeneralSpecifications

Item

SynchronizationSystem

I/FProtocol

I LogicLevel

‘“d ~

STOROBE

Busy

3-2. ConnectorSignals

ACK

ViaexternallysuppliedSTROBEpulse
ByACKandBUSYsignals

I CompatiblewithTTLlevel

9 ~s

h

1

Fig. 1-5TimingChartsofParallelInterface

Specifications

I

T

+

T: More than().5 ILS

PinNo SignalName

1

STROBE
2 DATA1
3

DATA2
4 DATA3
5
6
7
8
9

10

11

DATA4

DATA5

DATA6

DATA7

DATA8

ACK

BUSY Lowwhenprinterreadytoreceivedata.

Goesfromhighto low(for>0.5ps)whenactive
Highwhenactive
Highwhenactive
Highwhenactive
Highwhenactive
Highwhenactive
Highwhenactive
Highwhenactive
Highwhenactive
9VSlowpulseacknowledgesreceiptof data

FunctionDescription

12 PAPER Highwhenpaperout.Canbe disabledwithDIPswitchsetting.
13

SELECT

Highwhenprinterison-line

14,15 NC

16
17
18

SIGNALGND

CHASSISGND

+5V +5VDCoutputfromprinter

19-30 GND

31
32
33

34,35

RESET Whenthisinput signalis low,printerisreset

ERROR

EXTGND Externalground

NC

36 SELECTIN

Signalground
Chassisground(isolatedfromsignalground)

Twistedpairgroundreturn

Outputs lowwhenprintercannotcontinue,duetoan error

Alwayshigh

-8–

GENERAL SPECIFICATIONS

Serial Interface (option)

Whenusing theserialinterface,theoptionalSerial-PmallelConvertermustbeconnectedwiththeprinter.

4-1. GeSpe

Item

Interface
SynchronizationSystem
Baudrate

Wordlength

Startbit:
Databit: 7or8 bits(selectable)
Paritybit: Odd,EvenorNone(selectable)
Stopbit:

Signalpolarity

Mark:
Space:

Handshaking

Databuffer 8KB(standard)

4-2. Connector Signals and Functional Descriptions

Pin No. \Signal name I Direction

I

1 GND
2
3
4

5
6

7

8-10

11

12– 19

20

21–25 NC

TXD OUT
RXD IN

RTS OUT Alwaysspace.
CTS

NC

GND

NC

RCH OUT

NC

DTR OUT

RS-232Clevel
Asynchronous

150-19,200 bitpersecond(BPS)[selectable]
150,300,600>1200,2400,4800,9600, 19200BPS

1bit

Morethen1bit length

Logic“l” (-3V to-15V)
Logic“O”(+3Vto+15V)

DTR
XON/xOFF
ETX/ACK

—

.

—

Printer’schassisground.
Thispincarriesdaiafromtheprinter.
Thispincarriesdatato theprinter.

Thispinis spacewhenthecomputerisreadyto senddata.
Thisprinterdoesnotcheckthispin.
Unused.
Signalground.
Unused.
Thisprinterturnsthis pin spacewhenit is readymreceivedata.
Thislinecarriesthesamesignalaspin20.
Unused.
Theprinterturnsthispinspacewhenitisreadyto receivedata.
Unused.

Specifications

Function

–9–

GENERAL SPECIFICATIONS

4-3. DIP Switch Settings

Switch

I

1 8data bits
2

3
4
5
6
7
8

AllswitchedaresetON whentheprinterleavesthe factory.

I
I

Baud rate Switch 6

150

Noparity
Handshakingprotocols- seetablebelow

Oddparity

Datatransferrate– seetablebelow

Protocol

DTRmode

XON/XOFFmode

ETX/ACKmode

300

600

I

I

1200
2400
4800
9600

19200

ON

7 databits
Paritychecked

Evenparity

Switch

I

I

Switch 7

OFF

OFF
OFF

OFF

\

ON
ON
ON
ON

I

I

I

3

ON

ON

OFF

OFF
OFF

ON

ON

OFF

OFF

ON
ON

OFF

I
I

I

I

Switch 4

ON

OFF

ON

Switch 8

OFF

ON

OFF

ON

OFF

ON

OFF

ON

I
I

I

I

I

1

I

–10 –

C 2

T O

1. B Di

M L B
2

2 GeF C

D I Op

2 PaIn
2 S In

2 Ed........................................................................................9

2 P H D C
2 P H TeDeC
2 CaM D C
2-2-5. CaM S C

2-2-6.P F M D C

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

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

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

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

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

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

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

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

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

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

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

1

1
1

1
1
1

1
1

20

2
2

l

2
2
2

P S U

3

4 Me

4-1.

4
4
4
4

R Ci
R b + L V De
PrCi

P H Me
P H CaMe

I R F Me
P F Me
De

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

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

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

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

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

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

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

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

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

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

2
2
2

2

2
2

2
2
2

30

I

I

THEORY OF OPERATION

Block Diagram

1.

Theblockdiagramofthisprinteris shown in Fig.2-1.

DaLa
(From Host Comp.tcr)

8

Parallel
Interface

Driver

Printer
Mechamsm

~-———.
IAutomat,c ~
~SheetFeederl

.——— —.

Control

[

EPROM
64 KB

I

+};

Panel

~ju~

DIP

Switch

RAM

Main Logic Board

Gate Array

Driver

7 .~

Print Head

Detectors

!’

Carriage

4

Paper Feed
Motor

Power
Unit

AC Power

Motor

1

s

(

Fig.2-1BlockDiagram

(1) MainLogicBoard

Thisboardreceivesdatafromthehostcomputerandstoresit intheRAMinthe orderofarrival.TheCPUon this
boardreadsthedatafromtheRAM,andeditsitaccordingto theprogramstoredin theROM.
Whentheeditingiscompleted,variousdrivesignalsfromtheCPUare sent to theprintermechanismto perform
printing.
<Explanation>

1

CPUM50734SP

● Controlsthis printer.

2

EPROMP.PD27C51264K-byte

. Containstheprogramwhichexecutescontroloftheprinter.

RAMHM62648K-byte

3

● Usedasstackarea,workareaand databufferof theCPU.

4

Parallelinterface

5

Gatearray(customIC)
. Inputsoroutputsseveralsignals.
Driver

6

● ThedataeditedbytheCPUandgatearrayare sent to theprintermechanismafterconversionto the signal

fortheprintheaddrive,carriagemotordriveandpaperfeedmotordriverespectively.

7

ControlPanelBoard
. Thispanelcircuitis formanualoperationoftheprinter.

(2) PrinterMechanism

Theprintermechanismconsistsofa printhead,carriagemotor,paperfeedmotoranddetectors.

(3) PowerSupplyUnit

ACpowerisconvertedto25VDCand 5VDC.

– 13–

THEORY OF OPERATION

2. Main Logic Board

I O

2-1-1. PaIn
Communicationsbetweenthehostcomputerandthisprinterarefacilitatedviaparallelconnectors.Thissectionexplains
thehandshakeof thisinterface.
Thedatainputcircuit of thisinterfaceisshowninFig.

2-2.

CNI

1-

DATA1I

I
I

DATA8

STROBE

BUSY

I

I

ACK

~ ————————————————————,

DIN O]

DIN 7 \

—1

STBI

(
1

I

I

I

I

@

LS273

DQ

CLK

A

I

I

I

L ————————— — — — — —— ———

Q

LS244

AY

ii

5V

+

GateArray

————

; DO

r

1
I

r

I
1

I
[

i D7
!= ~

I

I
I

I

I

I

I

l—
IWR

I

I

I L

DO

- D7

Iii

CPU

Fig.2-2DataInputCircuitwithParallelInterface

Thefollowingisan explanationofthis handshake.
(1)

WhentheBUSYsignalis LOW(Ready),thehost

computer outputs 8-bitdata 1through8 totheconnectorCN1.

Pin 1carriestheS&OBE pulsesignd-hm thehost~mputer &theprinter.ThissignalisnormalIyheld HIGH
bythe hostcomputer.Whenthehostcomputerhasdatareadyfortheprinter,itsetsthissignaltoLOWforatleast

0.5p.s.

(2)

gatearrayofthemainlogicboardreadsdata1through8atthetimeofSTROBEsignalfall,andthenturnsthe

The

BUSYsignalandP-BUSYsignaltoLOW.
Whenthe BUSYsignalofthegatearrayissettoLOW,theBUSYsignalofconnectorCNlwillbeturnedtoHIGH,

(3)

notifyingthehost computerthatdatacannotbe accepted.

(4)

TheCPUisinformedviatheDOdatalinethattheP-BUSYsignalisLOW.TheCPUthensettheRDsignaltoLOW
andread thedata.

(5)

Uponcompletionofthedatareading,theCPUnotifiesthehostcomputerofthedatareceivablestatebysettingthe
BUSYsignalofconrtectorCNIandtheACKsignaltoLOW.Thisconcludestheexpkmationoftheparallelinterface
handshake.Thefollowingchartshowsthetimingchartof thehandshake.

–14 –

““K u

D

w

THEORY OF OPERATION

9

)

I

STOROBE

- i

BUSY

2-Ser(o

Whentheserialinterfaceis used,an optionalSerial-ParallelConverterisrequired to be installed.The converterwill
changethevoltagelevel(RS-232C

C 1

I

R

T

,

1

~ TTL)andthedatatransfermethod(Serial

I

Fig.2-3TimingChartof ParallelInterface

R

I 4

T

I

T

TT

J-Ill

I

M t (

~ parallel).

C B

P50

P
P
P

P
P

P
P

T=

P

P

P

P

P

P

, D

,

, D

1
I
I
I

D

D
D

D
D

S

B

I

$-

1

Fig.2-4SerialInterface(intheSeriai-ParaiielConverter)

– 15-

M

I

THEORY OF OPERATION

TheIC101isadualRS-232Cdriver/receiverwhichincludesa capacitivevoltagegeneratorto supplyRS-232Cvoltage

levelsfroma single5Vsupply.
DatafromthehostcomputerissentfromRXDviaICIOlandisinputtotheMPU.SerialdatainputtotheMPUisconverted

intoparalleldata,andoutputtothemainlogicboard.Conversely,paralleldatareceivedbytheMPUisconvertedthere
intoserialdata,andoutputtothe TXDterminalviaIC101.
TheCTSterminalishardware-connected,notsoftware-connected.(Thissignalisnotchecked.)
Thisprinter employs 3 differenttransfermethods,whichcanbe selectedusingthedip switches.(Referto Chapter1,
4-3

SettingDipSwitches)

(1)

DTRmethod
TheDTRsignalisconsideredaBUSYsignalatthehandshake,andwhenthedata buffercapacityis256bytesor
less,theDTRsignalis givena markedstatus,meaningitcannotreceivedata.Whenthecapacityofthedatabuffer
increasesto512bytes or moreduringprinting,theDTRsignalis givena spacestatus,whichindicatesthatit can
receivedata.

(2)

XoN/Xommethod
Whena handshakeiscarriedoutwiththehost computer,theXoN/Xommethodmakesuseof ASCIIcodes(DCl
andDC3).(DClandDC3arecalledXONandXom,respectively.)Whentheprinterbufferisfull,DC3(ASCIIcode

19)is outputtotheTXDterminal,andthecomputerreceivesarequesttostopdatatransfer.ThepnnteroutputsDC3
untilit(thecomputer)stopsdatatransfer.Duringprinting,whenthebufferfullstatusiscancelledanddatacanbe
received,DC1(ASCIIcode17)isoutputtotheTXDterminal.WhenDC1isoutputfromtheprinter,thecomputer
followsthedataformat,andbeginsdatatransfer.DatatransferwillcontinueuntilDC3 isoutputagain.

(3)

ETX/ACKmethod
Thedatablockisconfiguredasshownbelow,buttheinitialSTXcodeisnotnecessary.WhenanSTXcodeissent
fromthehostcomputer,that1byteisignored.Whenthe ETXcodeisreceived,that1byteisnotregardedasdata,
anACKorNACKcodeis senttotheTXDterminal,andthehostcomputerisinformedthatdatareceptionhasbeen
completed.
Datablockform:

+(

—

ETX

6 7

0

(

1

0

1

stop

B

---

,;

–-+

I

I

STX

S
B

—

(

DATA(8KBorless)

I ? 3 4

—

Fig. 2-5DataFormat

D B

5

1

–16 –

(1) DTRmethod

THEORY OF OPERATION

R

‘T~

“

O

(2) XoN/xoFFmethod

R

T

D

R

O

I I

I

I

I I

Ill

I

,

1

I 2

All

X();t ‘

1

1

12

u

@

N F (w t e a t d b b 2 h l )

@ N E ( t e a t d b b b m

X

X

1

1

II

X x

1

1111
II

1

I

B

(3) ETX/ACKmethod

R

T

D

R

O

B

@ N F (w t e a t d b b 2 h l )
@ N E ( [ e a t d b b b m
@ E ( t d b b e )
@ P E F E B O f

@ N F ( t e f t d b b b l
@ N E ( [ e a t d b b 1 b m

A (

I

II

v

II

E

E

1

F

F

II

E

E E

I I I II I

1111

F N

F

II

‘1tI

I

I I 11 I

F–

E

Fig. 2-6DataInputTimingChartwithSerial Interface

– 17–

THEORY OF OPERATION

2 General Flow C

Ageneralflowchartofeditingand printingoperationsispresentedinFig.2-7.

POWER ON

I

1

&

Read Data

T

NO

YES

Control Code

Processing Storage

4

Data

t (L

Data Processing

or Printing

(Print out of data)

Q

4

Fig.2-7GeneralFlow ChartofEditingandPrinting

NO

Return Action

–18 –

THEORY OF OPERATION

2-2-1. Editing

Datastoredin theRAMisreadoutsequentiallyby theCPUandtheneditedaccordingtoa functioncodethathasbeen
specifiedinadvance.
ThiseditingtakesplacesuntiltheCRorCR+ LF codeappearsorthe linebufferbecomesfull.

2-2-2. P H DrCi

EditedprintdataisoutputtoterminalQof LS273inthegatearraythroughtheCPUdatabus,asregulatedbytheissue
timingofa WRsignal.However,as forpin9 (HD9)oftheprinthead,thedataisoutputtotheterminalQofLS74upon
issue of thenextWRsignaI.Whenallthe datais receivedforprinting,anenergizedtimecontrolsignalis outputfrom

portP04oftheCPU.ThisallowstheprintdatatobeoutputtoHD-1-9 ofthegatearray.WhentheprintdataisHIGH,

thetransistorTR8willbe turnedONfor 335pS, energizingtheprintheadsolenoidto drivetheprint head.

+ 5V

\

D1

p H

/

Fig.2-8Print HeadDrivingCircuit

2-2-3. P H TeDeC

.Theprintheadtemperaturedetectioncircuitprotectsagainstdamagewhentheprint headheatsup abnormally.

Fig.2-9 shows thiscircuit.
Theprintheadhasa thermistortoshowthetemperatureoftheheadsolenoids.Thisthermistors anelementthatconverts
temperatureintovoltage.Itsoutputvoltageisinputto an analogpinof theCPU.TheCPUcomparesthisinputvoltage
againstitsreferencevoltageVwFtofindoutthetemperatureoftheheadsolenoidsandcarriesoutthefollowingoperations
dependingonthetemperature.

0 Ts95“C

● Normalprint operations

@ 95“C c T < 105‘C

. Intervalprinting;The print head stays for approximately0.5 secondwheneverit finishesl-line. When the

temperaturefallsbellow95”C,normalprintingisresumed.

@ 105‘C ST

. Thelinebeingprintediscompleted,thenprintingstops.Whenthethermistor’stemperaturefallsbelow105“C,

intervalprintingisresumed.

- 19–

+5V

T

Y $

F ( ~

I

Fig.2-9Print HeadTemperatureDetectionCircuit

2-2-4. CaM DrC

This printeremploysasteppingmotorasthecarriagemotor.Unlikeregularmotorsonthemarket,this steppingmotor

willnotoperatejustby connectingittoa powersource.Themotoroperatesonlywhena drivepulseisfedtoit,buteven
then,it turnsonlya certainangle.This steppingmotoris characterizedby 4-phasestepping.Controlof the motoris
facilitatedbyphase1-2excitation.Thefollowingshowsthecarriagemotordrivecircuitandthecontrolsignalgenerated
bythephase

1-2

excitationmethod.

+ + C

1 *

C

p
P

P

P

Fig.2-10CarriageMotorDrivingCircuit

1

;

(

–20

I

;

F L R

Mode

Operation: +25VDC

Standby:

–

01 :

03 ; :

Theutilizationof voltageappliedtothecarriagemotorisdescribedbelow:
Voltageappliedtothecarriagemotorischangedbysetting
portP30 of the CPU to HIGH or LOW and by turning
transistorsTR12andTR13ONorOFF.
WhenTR13isON,+25Vissuppliedtothecarriagemotor
andwhenTR13isOFF,+5Vis suppliedtothemotorvia
diodeD1.

;ON :

; , I : I

,,; ,

F R L ~

L

Fig.2-11CarriageMotorDrivingSignals

Carriage MOICN

Voltage Application

MotorDrive

+5VDC HoldingBias

I

THEORY OF OPERATION

2-2-5. Carriage M S C

Sincethecarriagemotoris a steppingmotor,tie carriagecanbestoppedatadesiredpositionbycontrollingacceleration
anddeceleration.Thecarriagecanalsomovebackward.
Therotationalspeedof thecarriagemotoris setby thenumberof pulsespertimeunit.Thecharacterpitch(horizontal
chamctersize)in eachprintmodeisdeterminedby changingthisrotationalspeed(orcarriagetransferspeed).
(1) Atstart-upof themotor:

Thenumberofpulsesinput to themotorincreasein steps,reachinga certainfrequency.

(2) Tostop themotoc

Thenumberof pulsesinputtothemotordecreasesinsteps,in orderto graduallybringthemotortoa halt.

(3) Whenprintingiscarriedout:

Pulsesof a uniformpulsewidthare suppliedforprinting.

2-2-6. P F M DrC
Again,a steppingmotoris employedasthepaperfeed motor,whichturnsa certainangleonlywhena drivepulseis
received.This4-phasesteppingmotoriscontrolledby the phase1-2excitationmethod.Thefollowingshowsthepaper
feedmotor drivecircuitand thecontrolsignalgeneratedbythephase1-2excitationmethod.

Fig.2-12PaperFeedMotorDrivingCircuit

-21 –

6

+

T

P

T

P

P

T

P

T

P

)

)

t

C

I

I

Fig.2-13PaperFeedMotorDrivingSignals

Theutilizationof voltageappliedto thepaper feedmotorisdescribedasfollows.

Mode Voltage Application

1

LD3 I

C

I

I I

13

+3

-+0

4

I

I

I

I

&

P F

M

d

Mot

Operation

Standby:

VoltagetothepaperfeedmotorischangedbysettingCPUportP31toLOWor HIGHandbyturningtransistorsTR19

andTR18ONorOFF.
WhenTR18isturnedon,+25Visappliedtothepaperfeedmotor.
WhenTR18isturnedoff,+5Vis suppliedtothemotorviadiodeD3.

+25VDC

+5VDC HoldingBias

MotorDrive

- 22–

1

THEORY OF OPERATION

2 R Ci
T RESETsignalinitializesthecircuitelementsandpreventsoperationerrorswhenthepoweristurned on.

TheRESETsignalisoutputforapprox.34ms.whenthepoweristumedon,orwhiletheRESET(INPUT-PRIME)signal

is beingoutputfromthehostcomputer.

——

\

HDI

HD

(

HD9

IN-PRIME

CN1

T

I

I
/

I

+ .5V

t

OUT D

IC6 ~

GND

.———————— — ———

I

I

I

5

1

,

c1 1

J=

WD%? Do —

)

r I

1

DOR&

))

I

I

I

d

+ 5V

A

+25V

I

Fig.2-14ResetCircuitandProtectionCircuit.

● PowerOnReset

1 Whenthepoweristurnedon,theRESETsignalisoutputtoPin5 ofIC6(M51953BL)forapprox.34msec.This

timelengthisdeterminedbyexternalcapacitorCl 1(0.lP.F),anditcanbe calculatedbythe followingformula.

T = 0.34

2 ThisLOWsignaltriggersRESETcommandto theCPUandtheRESETterminal(RES)of thegatearray.

Resettingthe CPUandthegatearraywillignoreallthedrivesignalsforthe carriagemotor,thepaper feedmotor

3

andthe printhead,preventingoperationerrorsatpowerON.

. Resetby InputPrimeSignalfromHostComputer
1 Theinputprimesignalfromthehostcomputerisoutputtopin 31of theconnectorCN1.

2 ThisoutputsignalwillsettheterminalINIT2 oftheCPUtoLOW,executinginterruption.Then,theCPUwillbe

initialized.

X Cll (PF)WK.

–23 –

THEORY OF OPERATION

2 R b + V D

Avoltage-detectingIC(IC6inFig.2-14)detectsmomentarydropsin voltageorunstablevoltagesupply(duetopower
failures,etc.)on the+5Vline.Ifthevoltageonthe+5Vlinefallsbelow4.25V,theRESETsignalappearsattheoutput
terminalofthe voltage-detectingIC.

V

5

OUT

VoltageA

o
V A

–— – ——

~

=

*

X ( [

t

w

R2::

()

1,~sv

V

91

t

5pA

+

1

. .

A4

GND

Cd

Fig.2-15EquivalentCircuitof

Fig.2-16OperationalTimingChart

Voltage-DetectingIC

2

PrWection Circuit

Thisprinterisprovidedwitha protectioncircuitwhichshutsofftheprintheadandmotordrivingcircuitsin theeventof
a CPUmalfunction.(RefertoFig.2-14)

TheCPUnormallyoutputsaLOWlevelsignalfromtheterminal(JVDOUT).
However,iftheCPUmalfunctions,itcan notoutputthissignal.

Whenthe LOWlevelsigmlisnotoutputfromtheCPU,theinputterminal(Cd)ofthevoltage-detectingICgoestoLOW
andtheRESETsigmlisoutputfromtheoutputterminal(OUT)of the voltage-detectingIC.Bythissignal,theCPUand
thegatemay arereset;andtheprirtthead,thecarriagemotorandpaperfeedmotordrivingsignalsareignored,protecting
theprinter fromthe CPUrunaway.

–24 -

THEORY OF OPERATION

3. Power Supply Unit

Fig.2-17showsthepowersupplyunit.
TheACpowerissteppeddownto Vsl andVS2bythepowertransformer.TheVsl powerisfull-waverectifiedbythe
DB1rectifierstackandsmoothedby electrolysiscapacitorC4. The smoothedDCpoweris convertedintothe stable
25V’DCpowerbythechoppercircuit,whosemaincomponentisIC1.TheVS2 powerisfull-waverectifiedbytheDB2
rectifierstackandsmoothedbytheelectrolysiscapacitorClO.PartofthissmoothedVs20utputisconvertedintothestable
5VDCpowerbyfixedvoltageIC2.

Input

output

VoltageRange
120VAC
220VACand240VAC

MaximumCurrentoutput

0.8A

0.5A

5VDC?2.5% 0.83A

25VDCti%

1.89A

Service

Forlogic circuitdrive,
Formotor holding

Forprintheaddrive,
Formotor holding

Typeofcircuit

Dropper

Chopper

+25V

t

+5V

Fig.2-17PowerSupplyUnit

–25 –

THEORY OF OPERATION

WewillexplainthechoppercircuitintermsofFig.2-18,a simplifiedversionofFig.2-17.IC1isa pulse-widthcontrol
switchingregulator.It hasa referencevoltagesection,oscillationsection,pulse-widthcontrol section,and power
transistors.Fig.2-19showsanequivalentcircuitforIC1.
ThechoppercircuitswitchesthepowertransistorsinIC1onandofftodivideinputvoltage
thosepulseswithchokecoilL2andcapacitorC9toobtainthedesiredoutputvoltage

Since thepulse width control sectiondetermines theratio of thetimethatthepower transistorsareonandoff bycomp~ing
the output voltage with the reference voltage, the output

voltagecanbeheldsteady.
Inorderwords,iftheoutputvoltagefallsbelowthereferencevoltage,thepulsewidthcontrollerextendsthetimethatthe
powertransistorsare on,thusraisingtheoutputvoltage.TheoutputvoltageVOUTcanbeexpressedwiththefollowing
equation.

VINintopulsesandsmoothes

VOUT.

Vour = VIN.

TON :

TOFF :

T:

Durationthepowertransistorsareon
Durationthepowertransistorsareoff
TON+ TOFF(constant)

TON

TON+ TOFF

= VIN. +

DiodeD1formsa pathwaythroughwhichtheenergyaccumulatedonchokecoilL2whilethepowertransistor
dischargedwhilethepowertransistorsareoff.

—————————._——————

I

PowerTransistor

o

V

o

I

I
I

I
I

I
I

i

i
I

I

Ic 1

PulseGenerator
Block

I

————

I

1

1—

I

I

I

1 L

LZ

Y

D1

R3

+

4)

z C9

o

o

L _ –

Fig. 2-18ChopperCircuit

a on

is

r-=w-

Os

F C

1

3

(

Inh

\

;w’M

s

‘

I
F
F

R Q--

Q-

1 r

Iv

D

G

i

4

1

Fig. 2-19 Equivalent Circuit for Voltage Regulator IC1

–

–26