Star Micronics LS-5 Series Technical Manual

LASER PRINTER

LS-5 SERIES

TECHNICAL MANUAL

[SECOND EDITION]

NOTICE

form whatsoever, without STAR’s express permission is forbid-

den.

• 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 in-

formed of them.

• The above notwithstanding, STAR can assume no responsibility

for any errors in this manual.

INTRODUCTION

1

2

3

4

5

6

This manual is an introduction to the laser printer as shown below.

It is intended for use as a reference for maintenance procedures.

This manual is prepared for use at a technical level and not for the general user.

• LS-5EX

• LS-5TT

• LS-5

This manual is divided into the following sections:

Chapter 1 General Specifications

Specifications, safety information

Chapter 2 Theory of Operation

A description of the principles of the electrical and mechanical systems and their functions

Chapter 3 Parts Replacement and Adjustments

Explanation of disassembly, reassembly, and adjustment procedures

Chapter 4 Maintenance Guide

Contains an overview of steps to assist in recovering from a breakdown, connector layout diagrams, wiring

connections, and other information helpful in maintenance operations.

Chapter 5 Troubleshooting

Contains breakdown analysis procedures used in repairing breakdowns.

Chapter 6 Parts List

Illustrations showing disassembly diagrams, part numbers, and part names

• First edition : Dec. 1992

Second edition : Feb. 1993 Add LS-5 model

– 2 –

GENERAL SPECIFICATIONS

1

CHAPTER 1

GENERAL SPECIFICATIONS

1. General Specifications..........................................................................................3

2. Pin Functions on Interfaces .................................................................................5

2-1. Parallel Interface ..................................................................................................... 5

2-2. Serial Interface........................................................................................................ 5

2-3. AppleTalk Interface................................................................................................. 5

3. Safety Information.................................................................................................6

3-1. Power Supply.......................................................................................................... 6

3-2. Drive Parts............................................................................................................... 6

3-3. Safety Devices ........................................................................................................ 6

3-4. Laser safety............................................................................................................. 7

4. Printer Components..............................................................................................8

– 2 –

GENERAL SPECIFICATIONS

– 3 –

GENERAL SPECIFICATIONS

1. General Specifications

(1) Type Desk-top page printer

(2) Printing method Electro photography

(3) Printing speed 5 pages/min (A4 size)

3.56 pages/min (legal size)

(4) Time for first print 27 seconds or less

(5) Warm-up time 1 min or less (after power on until the printer warms up at ambient

temperature of 20°C with rated AC voltage input)

(6) Optical system

Laser Semiconductor laser beam

Scanning system Rotating scanning mirror

Scanning pitch

Horizontal 300 dots/inch

Vertical 300 rasters/inch

(7) Printing system

Photosensitive drum OPC

Exposure method Laser scanning system

Paper feed Cassette feed

Front paper tray feed

Fusing method Thermal fusing by heated rollers

Toner supply Included in replaceable EPX toner cartridge

(8) Paper feed sources

Standard 250-sheet deck with cassette

50-sheet front paper tray

Option 250-sheet deck with cassette

500-sheet deck with cassette

(9) Paper

250 universal cassette

Paper size Letter (8.5" × 11"), A4, Executive, B5

Capacity 250 sheets, or maximum 27 mm loading height

250 legal cassette

Paper size Legal 14" (8.5" × 14"), Letter (8.5"

× 11")

Capacity 250 sheets

250 envelope cassette

Paper size COM-10, Monarch, DL, C5

Capacity 30 envelopes

500 letter cassette

Paper size Letter (8.5" × 11")

Capacity 500 sheets

500 A4 cassette

Paper size A4

Capacity 500 sheets

500 B5 cassette

Paper size B5

Capacity 500 sheets

Front tray

Paper size Letter (8.5"

× 11"), A4, Envelopes

Capacity 50 sheets or 5 envelopes

(10) Paper weight (plain paper)

Front paper tray 60 g/m

2

to 135 g/m

2

Cassette feed 60 g/m

2

to 105 g/m

2

(11) Print delivery Face-down

– 4 –

GENERAL SPECIFICATIONS

(12) Acoustic noise (in accordance with ISO 7779)

Stand by 37 dB or less

Printing 45 dB or less

(13) Environment

Printer with EPX toner cartridge

Operating temperature 5°C to 35°C

Operating humidity 15% to 85%RH (without condensation)

Storage temperature –20°C to 40°C

Storage humidity 5% to 95% (without condensation)

Altitude 0 to 8200 feet (0 to 2500 meters)

Printer without EPX toner cartridge

Storage temperature –20°C to 60°C

Storage humidity 5% to 95% (without condensation)

Altitude 0 to 49200 feet (0 to 15000 meters)

(14) Power consumption

100 - 115V Max. 450W

220 - 240V Max. 500W

(15) Printable area The guaranteed printing requires a margin of 4 mm from each edge of the

paper.

(16) Dimensions (W × D × H) 352mm × 393.5 mm × 253mm

(17) Weight Approx. 12kg (without EPX toner cartridge)

(18) Line voltage Rating Range

Voltage 100 - 115V 90 to 132V

220 - 240V 198 to 264V

Frequency 50/60Hz 47Hz to 63Hz

(19) Host interface

LS-5EX

Parallel Centronics

Serial RS-232C

Optional AppleTalk (when an optional ROM board MS is installed)

LS-5TT

Parallel Centronics

Serial RS-232C

AppleTalk

LS-5

Parallel Centronics

Serial RS-232C/RS-422A

(20) RAM

Resident 1MB (LS-5EX)

2MB (LS-5TT)

0.5MB (LS-5)

Option Max. 6MB on RAM expansion board (LS-5EX/TT)

Max. 4MB on RAM expansion board (LS-5)

(21) Emulation

LS-5EX Standard: PCL5 and GL/2(HP Laserjet 3)

Option: TrueImage (with optional ROM board MS)

LS-5TT PCL5 and GL/2(HP Laserjet 3)

TrueImage (Apple LaserWriter NTX)

LS-5 PCL4 (HP LaserJet IIP)

ESC/P (Epson FX-286)

(22) Font

Resident 14 bitmap fonts

8 scalable fonts (LS-5EX/TT)

35 TrueType scalable fonts (LS-5TT only)

Option Font cartridge

– 5 –

GENERAL SPECIFICATIONS

2. Pin Functions on Interfaces

2-1. Parallel Interface

Pin No.

Signal

Direction Function

Name

1 STROBE IN Goes from High to Low (for at least 0.5 microseconds) when data are valid.

2 DATA1 IN

3 DATA2 IN

4 DATA3 IN

5 DATA4 IN

6 DATA5 IN

7 DATA6 IN

8 DATA7 IN

9 DATA8 IN

10 ACK OUT A low pulse acknowledges receipt of data.

11 BUSY OUT Low when the printer is ready to receive data.

12 PAPER OUT OUT Goes High if the printer runs out of paper.

13 SELECTED OUT High when the printer is online.

14-15 N/C Unused

16

SIGNAL GND

Signal ground

17

CHASSIS GND

Printer’s chassis ground, isolated from signal ground.

18 +5VDC OUT External supply of +5VDC

19-30 GND Twisted pair return signal ground level.

31 PRIM IN LS-5 model does not check this signal.

LS-5EX and TT are not connected.

32 FAULT OUT Goes Low to signal that the printer cannot print due to an error condition.

33-36 N/C Unused. In case of LS-5 model, pin no. 33 and 35 are always HIGH.

2-2. Serial Interface

Pin No.

Signal

Direction Interface Function

Name

1 GND 232C/422A Chassis ground

2 TXD OUT RS-232C Transmitted data

3 RXD IN RS-232C Received data

RXD– IN RS-422A Received data–

4 RTS OUT RS-232C SPACE when the printer is ready to receive data.

But this printer does not check the signal.

5-6 N/C Unused

7 GND 232C/422A Signal Ground

8 N/C Unused

9 TXD+ OUT RS-422A Transmitted data+

10 TXD– OUT RS-422A Transmitted data–

11-17 N/C Unused

18 RXD+ IN RS-422A Received data+

19 N/C Unused

20 DTR OUT RS-232C SPACE when the printer is ready to receive data.

21-25 N/C Unused

2-3. AppleTalk Interface

Pin No.

Signal

Direction Function

Name

1 HSKo OUT Handshake out (always GND)

2 HSKi IN Handshake in

3 TXD– OUT Transmitted data –

4 GND Signal ground

5 RXD– IN Received data –

6 TXD+ OUT Transmitted data +

7 N/C Unused

8 RXD+ IN Received data +

Eight-bit character data. DATA8 is the most significant bit; DATA1 is the least significant bit.

High is logic 1 and low is logic 0.

– 6 –

GENERAL SPECIFICATIONS

3. Safety Information

In order to prevent accidents from occurring while maintenance is being carried out, all warnings and precautions should

be strictly observed while working. Never attempt any kind of dangerous work when servicing this machine.

The precautions noted below are only a few of the situations which could foreseeably occur during maintenance

operations. Please make sure every safety precaution is observed while working.

3-1. Power Supply

In order to prevent electrical shock, burns, damage to the equipment, and other problems, always make sure the power

supply is turned off and the power supply cable has been unplugged before maintenance work is carried out.

If the power must be left on in order to measure voltage or for other reasons, make sure sufficient precautions are taken

to prevent electrical shock, and follow the procedures noted in this manual.

3-2. Drive Parts

Inspection of drive section parts such as sprockets and gears should be carried out using a hand crank.

DANGER: Never inspect these parts while the equipment is in operation!

3-3. Safety Devices

Thorough consideration should be given to safety devices designed to prevent accidents (fuses, interlock switches, etc.)

as well as those handled by the user in the course of operating the equipment (covers, panels, etc.), in order to make sure

they fulfill their function as safety equipment.

DANGER: In order to prevent exposure to the laser beam contained in the printer, the following precautions must always

be strictly observed.

Exposure to the laser beam can result in blindness.

• Never open cover (ROS assembly) that has the label of figure 1-2.

• When disassembling and adjusting the equipment, always make sure the power supply has been turned

off first.

• This equipment is provided with a two-stage safety switch function, so that it can be operated even with

the covers removed, by pressing the interlock switch. When using this method of operation, never short

the other switch at the same time (the second switch is pressed when the actuator at the back of the EPX

toner cartridge attachment section is pressed).

• When servicing the optical system of the printer, be careful not to place screwdrivers or other reflective

objects in the path of the laser beam.

Be sure to take off accessories, such as watches and rings, before working on the printer. A reflected beam,

though invisible, can permanently damage your eyes.

Because the laser beam is invisible, be especially careful when servicing the optical system.

– 7 –

GENERAL SPECIFICATIONS

3-4. Laser safety

This printer is certified as a Class 1 laser product. This means that this laser product does not emit harmful laser beams.

This printer emits a Class 3B laser beam, but the beam is entirely enclosed within a protective case and an external cover,

and cannot leak from the printer while the printer is in use.

CLASS 1 LASER PRODUCT.

LUOKAN 1 LASERLAITE.

KLASS 1 LASER APPARAT.

CLASS 3B LASER

WAVE LENGTH 780nm (INVISIBLE)

RATED POWER 5 m W

LUOKAN 3B LASER

AALLONPITUUS 780nm (NÄKYMÄTÖN)

TEHO 5mW

Figure 1-1 Class 1 Label

Figure 1-2 Caution Label

VARO! Avattaessa ja suojalukitus ohitettaessa olet alttiina näkymättömälle lasersäteilylle. Älä katso

säteeseen.

VARNING! Osynlig laserstrålning när denna del är öppnad och spärren är urkopplad. Betrakta ej strålen.

– 8 –

GENERAL SPECIFICATIONS

4. Printer Components

Figure 1-3 External Dimensions

Figure 1-4 Front View

Figure 1-5 Rear View Figure 1-6 Inside View

2

CHAPTER 2

THEORY OF OPERATION

1. Printing Process..................................................................................................11

2. Paper Transportation ..........................................................................................14

3. Functions of Main Parts......................................................................................15

3-1. Cassette Feed.......................................................................................................... 15

3-2. Paper Transportation .............................................................................................. 17

3-3. Fusing and Paper Exit............................................................................................. 19

3-4. Drive and Photographics........................................................................................ 20

3-5. Electrical .................................................................................................................. 22

– 10 –

THEORY OF OPERATION

– 11 –

THEORY OF OPERATION

1. Printing Process

The printing process of this system consists of repetition of the following basic seven steps:

Charging Scanning exposure Developing Transfer Separation Fusing Cleaning

The following schematic diagram will help to explain the printing process.

: Laser Beam

: Paper Path

Figure 2-1 Printing Process

– 12 –

THEORY OF OPERATION

• Descriptions of Printing Process

Process Contents

Charging The surface of the drum rotated by the BCR (bias charge roll) in the EPX toner cartridge

is negatively charged uniformly.

The ROS assembly converts image signals from the main logic board into optical signals

(laser beam), the laser beam scanning on the drum enabling exposure.

Scanning Exposure When an image is present, a laser is emitted. The laser beam is irradiated on the drum

surface, the negative charge of irradiated portions moves to the earth, thus enabling an

invisible electrostatic latent image to be formed on the drum surface.

The electrostatic latent image on the drum surface attracts toner on the magnetic roll surface

in the EPX toner cartridge, which is developed into a visible image on the drum surface.

Developing The toner is magnetic component. The magnet inside the magnetic roll causes the toner to

adhere to the roll, and the friction between the magnetic roll as it rotates and the CM

blade(Charge Metal Blade:the blade which charges the toner) converts the toner to a

negative charge, so that a thin layer of toner is formed on the surface of the magnetic roll.

The positive charge is impressed from the back of paper by the BTR (Bias Transfer Roll)

of the BTR assembly, thereby enabling toner on the drum surface to be transferred on the

paper.Transfer

Impressing plus charge from the back of paper causes the paper itself to be electrically

charged plus to adhere to the drum.

Separation

The eliminator of the trans. chute assembly causes electric charge of the paper to flow to the

earth to weaken the adhesion to the drum of the paper, and the flexibility of the paper enables

the paper together with transferred toner to be separated from the drum.

Fusing

Toner on the paper is fused on it in the fuser assembly by means of heat of the heat roll with

the heater rod as a heat source and pressure of the pressure roll.

Cleaning

Part of toner not transferred on the paper during transfer remains on the drum. This residual

toner is scraped away by the cleaning blade in contact with the drum surface.

Figure 2-2 Printing Process (Drum’s Surface)

–V

0

–360V

–V

0

–360V

–V

0

–360V

Laser Beam

Electrostatic Latent

Image (Invisible Image)

Toner Image

(Visible Image)

–270V

(Developing Bias)

Charging Scanning Exposure Developing

Voltage

Drum’s Surface

– 13 –

THEORY OF OPERATION

Cleauing

Scanning Exposure

Developing

Charging

Pressure Roll

Transfer

Separation

BTR

DC Bias

(+): 1.5µA (1000V)

(–): –600V

Magnetic Roll

Toner

CM Blade

Laser Beam

AC Bias: 200µA

(f=150Hz)

DC Bias: –360V

AC Bias: 1.6kVp-p (f=2.4kHz)

DC Bias: –270V

Toner

Cleaning Blade

BCR

Heat Roll

Stand by: 150°C

Printing: 160°C

Fusing

Paper

Eliminator

(φ19.65mm)

Drum

(φ30mm)

Figure 2-3 Printing Process (Seven Steps)

– 14 –

THEORY OF OPERATION

2. Paper Transportation

Paper transportation by the rolls is shown sequentially as follows:

Cassette feed Multi-purpose tray feed

Feed by the feed roll Feed by the pick up roll of the pick up roll assembly

Paper transportation by the turn roll of the turn roll

assembly and the pinch roll of the paper cassette

Paper transportation by the take away roll of the take away roll assembly and the pinch roll of the pick up

roll assembly

Paper transportation by the drum and the BTR of the BTR assembly

Paper transportation by the heat roll and the pressure roll

Paper exit by the exit roll of the exit roll assembly and the pinch roll of the fuser cover assembly

: Laser Beam

: Paper path

Figure 2-4 Paper Transportation

– 15 –

THEORY OF OPERATION

3. Functions of Main Parts

The following are brief descriptions with corresponding illustrations of the main parts. They are divided into the following

five blocks according to their architecture:

1. Cassette Feed

2. Paper Transportation

3. Fusing and Paper Exit

4. Drive and Photographics

5. Electrical

3-1. Cassette Feed

[1] Paper Cassette:

A cassette to hold cut sheets of paper.

Aligning the paper guide in the rear side to the paper causes the cam in the right rear to rotate, thereby changing the

location where the size spring is pressed.

A pinch roll corresponding to the turn roll of the turn roll assembly is also mounted.

[2] Feeder PCB (PCB: Printed Circuit Board):

The paper size switch and the no paper sensor are directly mounted on the board, the former detecting the cassette

paper size and the presence of the paper cassette with a combination of ON and OFF operations of the switches

according to the changes in the location of the size spring and the latter detecting the presence of sheets of paper in

the paper cassette.

With the no paper sensor, the state of the presence of sheets of paper being not detected shall be OFF.

[3] Feed Solenoid:

Controls operations (rotation and stop) of the feed roll assembly.

[4] Feed roll assembly:

Comprises a feed roll and feed clutch assemblies. When the feed solenoid is actuated, the spring clutch of the feed

clutch assembly becomes fixed, the feed roll assembly rotates by the drive from the drive assembly, the feed roll

delivering sheets of the paper from the cassette.

One full rotation of the feed roll assembly causes the spring clutch to be released, thus disabling the drive of the drive

assembly from being transmitted.

[5] Turn Solenoid:

Controls operations (rotation and stop) of the turn roll assembly (only when it receives PRFD (prefeed) signals from

the main logic board).

[6] Turn Roll Assembly:

When receiving a PRFD (prefeed) signal from the main logic board, the turn solenoid is actuated to cause the spring

clutch of the turn roll assembly to be released, thus stopping transmission of the drive from the drive assembly and

paper transportation, allowing the turn roll assembly to wait in front of the regi. sensor.

The turn solenoid,on receiving a START signal from the main logic board, stops operating to cause the spring clutch

to be fixed, the turn roll assembly rotating by the drive from the drive assembly to deliver sheets of paper.

When receiving no PRFD signal, the turn roll assembly is constantly transmitted the drive from the drive assembly

to deliver sheets of paper.

– 16 –

THEORY OF OPERATION

Figure 2-5 Cassette Feed

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Star Micronics LS-5 Series Technical Manual

Star Micronics LS-5 Series Technical Manual

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