Okidata OKIPAGE 16n Service Manual

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OKIPAGE 16n
Service Manual

All specifications are subject to change without notice.

P/N 59274401

Disclaimer

This document may not be reproduced without the written permission of Okidata Training and
Publications. Every effort has been made to ensure the accuracy of the information ocntained in this
training course. Okidata is not responsible for errors beyond its control.

Copyright / About Information

1997 by Okidata. All rights reserved.

First Release P/N 59274401 February, 1997

Written by:

OKI Data Corporation

11-22, Shibaura 4-chome, Minato-ku, Tokyo 108, Japan

Tel: +81 (Japan)-3 (Tokyo)-5445-6159 Fax: [phone]

Revised by Okidata Training and Publications

Contact

Please address any comments on this publication to:

OKIDATA

Training and Publications

532 Fellowship Road

Mount Laurel, NJ 08054-3499

Okilink Login Name: Technical Training

Internet Web Site: okidata.com

Copyright Listing

OKIDATA is a registered trademark of Oki America, Inc.
OKIDATA est une marque déposée de Oki America, Inc.

Adobe and PostScript are trademarks of Adobe Systems Incorporated, which may be registered in certain
jurisdictions.

Centronics is a registered trademark of Centronics Data Corporation.
HP and LaserJet are registered trademarks of Hewlett-Packard Company.
LocalTalk is a registered trademark of Apple Computer Inc.

Contents

1. CONFIGURATION ............................................................................................................... 1 - 1

1.1 System Configuration .......................................................................................................1 - 1

1.2 Printer Configuration........................................................................................................ 1 - 2

1.3 Optional Configuration.....................................................................................................1 - 3

1.4 Specification .....................................................................................................................1 - 5

1.5 Safety Standards ............................................................................................................... 1 - 7

1.5.1 Certification Label .............................................................................................................................. 1 - 7

1.5.2 Warning Label..................................................................................................................................... 1 - 7

2. OPERATION DESCRIPTION............................................................................................. 2 - 1

2.1 Main Control Board (BOARD-COM)..............................................................................2 - 3

2.2 Power Supply Board.........................................................................................................2 - 7

2.3 Relay/Driver Board (AOLC board).................................................................................. 2 - 9

2.4 Electrophotographic Process ..........................................................................................2 - 10

2.4.1 Electrophotographic process mechanism ......................................................................................... 2 - 10

2.4.2 Electrophotographic process............................................................................................................. 2 - 12

2.4.3 Process operation descriptions.......................................................................................................... 2 - 15

2.5 Paper Jam Detection .......................................................................................................2 - 24

2.6 Cover Open.....................................................................................................................2 - 25

2.7 Toner Low Detection ...................................................................................................... 2 - 26

2.8 Stacker-full Detection.....................................................................................................2 - 28

2.9 Page Size Detection ........................................................................................................ 2 - 28

2.10 PostScript Board (BOARD-PSBA) Optional ................................................................ 2 - 28

3. PARTS REPLACEMENT..................................................................................................... 3 - 1

3.1 Precautions for Parts Replacement ................................................................................... 3 - 1

3.2 Parts Layout...................................................................................................................... 3 - 3

3.3 How to Change Parts ........................................................................................................3 - 7

3.3.1 Rear cover, side cover (L) Assembly, face-up stacker Assembly, and I/F cover Assembly. .............. 3 - 8

3.3.2 Contact Assembly ............................................................................................................................... 3 - 9

3.3.3 DC fan motor .................................................................................................................................... 3 - 10

3.3.4 Manual feed hopper Assembly ......................................................................................................... 3 - 11

3.3.5 Side cover (R) (operator panel Assembly)........................................................................................ 3 - 12

3.3.6 Earth plate BK (R) (BOARD-PSBA, BOARD-COM)..................................................................... 3 - 13

3.3.7 Stacker cover Assembly, damper arm, and washer........................................................................... 3 - 14

3.3.8 Damper ............................................................................................................................................. 3 - 15

3.3.9 Stacker full sensor Assembly............................................................................................................ 3 - 16

3.3.10 Cable cover (cable guides A and B).................................................................................................. 3 - 17

3.3.11 Eject roller Assembly ........................................................................................................................ 3 - 18

3.3.12 Paper supply guide D........................................................................................................................ 3 - 19

3.3.13 Separator F........................................................................................................................................ 3 - 20

3.3.14 Front feeder roller Assy .................................................................................................................... 3 - 22

3.3.15 Hopping motor.................................................................................................................................. 3 - 23

3.3.16 Front feeder paper end sensor........................................................................................................... 3 - 25

3.3.17 Main chassis unit .............................................................................................................................. 3 - 26

3.3.18 Registration roller ............................................................................................................................. 3 - 29

3.3.19 Drum motor ...................................................................................................................................... 3 - 30

3.3.20 Idle gear ............................................................................................................................................ 3 - 32

Table of Contents TOC - 1 OKIPAGE 16n

Service Manual, P/N 59274401

3.3.21 Fusing Assembly............................................................................................................................... 3 - 33

3.3.22 Fuser pressure roller ......................................................................................................................... 3 - 34

3.3.23 EP lock shaft ..................................................................................................................................... 3 - 35

3.3.24 Hopping roller Assembly .................................................................................................................. 3 - 36

3.3.25 Outlet sensor lever ............................................................................................................................ 3 - 37

3.3.26 Toner sensor lever ............................................................................................................................. 3 - 38

3.2.27 Paper sensor lever ............................................................................................................................. 3 - 39

3.3.28 Inlet sensor lever............................................................................................................................... 3 - 41

3.3.29 Power Supply Board / Insulator........................................................................................................ 3 - 42

3.3.30 Paper end lever ................................................................................................................................. 3 - 45

3.3.31 Guide rail (L) Assembly ................................................................................................................... 3 - 46

3.3.32 Guide rail (R) Assembly ................................................................................................................... 3 - 48

3.3.33 Cover Frame ..................................................................................................................................... 3 - 50

3.3.34 LED head .......................................................................................................................................... 3 - 51

3.3.35 Separator Assembly .......................................................................................................................... 3 - 52

3.3.36 Transfer roller ................................................................................................................................... 3 - 53

4. ADJUSTMENT...................................................................................................................... 4 - 1

4.1 Maintenance Modes And Functions ................................................................................. 4 - 2

4.1.1 User maintenance mode...................................................................................................................... 4 - 4

User maintenance mode menu system................................................................................................ 4 - 5

4.1.2 System maintenance mode ................................................................................................................. 4 - 7

4.1.3 Engine maintenance mode ................................................................................................................ 4 - 10

4.1.4 EEPROM initialization ..................................................................................................................... 4 - 14

4.2 Adjustment When Replacing A Part............................................................................... 4 - 15

4.2.1 Setting of LED head drive time ........................................................................................................ 4 - 15

4.2.2 Resetting the fuser counter ............................................................................................................... 4 - 18

4.2.3 Destination setting ............................................................................................................................ 4 - 18

5. PERIODIC MAINTENANCE................................................................................................... 1

5.1 Periodic Part Replacement..................................................................................................... 1

5.2 Cleaning................................................................................................................................. 1

5.2.1 Cleaning of LED lens array ......................................................................................................................1

6. TROUBLESHOOTING PROCEDURES............................................................................ 6 - 1

6.1 Troubleshooting T ips........................................................................................................6 - 1

6.2 Points to Check before Correcting Image Problems ........................................................ 6 - 1

6.3 Tips for Correcting Image Problems ................................................................................ 6 - 1

6.4 Preparation for Troubleshooting....................................................................................... 6 - 2

Operator Panel Display....................................................................................................................... 6 - 2

6.5 Troubleshooting Flow.......................................................................................................6 - 2

6.5.1 LCD Status Message/Trouble List...................................................................................................... 6 - 2

6.5.2 LCD message troubleshooting.......................................................................................................... 6 - 15

1 The printer does not work normally after being turned on............................................. 6 - 16

[JAM error].............................................................................................................................. 6 - 20

2-1 Paper input jam (1st tray) ............................................................................................... 6 - 20

2-2 Paper input jam (front feeder) ........................................................................................6 - 21

2-3 Paper feed jam ................................................................................................................ 6 - 22

2-4 Paper exit jam ................................................................................................................. 6 - 25

3 Paper size error ...............................................................................................................6 - 27

4 Fuser unit error (ERROR 71), (ERROR 72), (ERROR 73) ...........................................6 - 28

5 I/F time-out between printer and optional tray (ERROR 81)......................................... 6 - 30

6 I/F time-out occurs between the printer and the operator panel (ERROR 80) . ............. 6 - 31

Table of Contents TOC - 2 OKIPAGE 16n

Service Manual, P/N 59274401

7 Communications with the host cannot be performed via the parallel interface. ............6 - 32

8 Data cannot be received through the OKI HSP interface ...............................................6 - 33

9 Synchronous serial I/O error (ERROR 74).....................................................................6 - 34

6.5.3 Image troubleshooting ...................................................................................................................... 6 - 35

1 Image are light or blurred ...............................................................................................6 - 36

2 Dark background density................................................................................................ 6 - 37

3 Black paper is output. .....................................................................................................6 - 37

4 Black belts or stripes in the vertical direction ................................................................6 - 38

5 Cyclic error ..................................................................................................................... 6 - 39

6 Print voids....................................................................................................................... 6 - 40

7 Poor fusing...................................................................................................................... 6 - 41

8 White belts or streaks in the vertical direction ............................................................... 6 - 42

9 Snowy print of high density pattern ............................................................................... 6 - 43

10 Blockly faded print .........................................................................................................6 - 43

7. WIRING DIAGRAM ........................................................................................................... 7 - 1

7.1 Interconnect Signal Diagram ............................................................................................ 7 - 1

7.2 PCB Layout ......................................................................................................................7 - 2

7.3 Resistance Check.............................................................................................................. 7 - 5

7.4 Program/Font ROM Location........................................................................................... 7 - 7

8. PARTS LIST........................................................................................................................... 8 - 1

Printer Unit (Figure 8-1 )...........................................................................................................8 - 2

Main Chassis Unit (Figure 8-2 ) 1 of 2...................................................................................... 8 - 4

Main Chassis Unit (Figure 8-2 ) 2 of 2...................................................................................... 8 - 6

Front Feeder Unit (Figure 8-3 ) .................................................................................................8 - 8

Base Unit (Figure 8-4 )............................................................................................................ 8 - 10

APPENDIX A: CENTRONICS PARALLEL INTERFACE .................................................. A - 1

APPENDIX B: HIGH CAPACITY SECOND PAPER FEEDER MAINTENANCE .......... B - 1

Preface ...................................................................................................................................... B - 1

1. Outline ............................................................................................................................. B - 2

1.1 Functions.............................................................................................................................................B - 2

1.2 External View and Component Names ...............................................................................................B - 2

2. Mechanism Description................................................................................................... B - 3

2.1 General Mechanicsm ..........................................................................................................................B - 3

2.2 Hopper Mechanism.............................................................................................................................B - 4

3. Parts Replacement ........................................................................................................... B - 5

3.1 Precautions Concerning Parts Replacement .......................................................................................B - 5

3.2 Parts Layout ........................................................................................................................................B - 7

3.3 Parts Replacement Methods ...............................................................................................................B - 8

3.3.1 Idle rollers ...........................................................................................................................................B - 9

3.3.2 AOLT-PCB .......................................................................................................................................B - 10

3.3.3 Hopping motor.................................................................................................................................. B - 11

3.3.4 Feed roller .........................................................................................................................................B - 12

3.3.5 Hopping roller rubber .......................................................................................................................B - 13

3.3.6 Side frame (L) assy ...........................................................................................................................B - 14

3.3.7 Side frame (R) assy...........................................................................................................................B - 15

Table of Contents TOC - 3 OKIPAGE 16n

Service Manual, P/N 59274401

4. TROUBLESHOOTING ................................................................................................ B - 17

4.1 Precautions Prior to the Troubleshooting .........................................................................................B - 17

4.2 Preparations for the Troubleshooting................................................................................................B - 17

4.3.1 LCD Status Message List .................................................................................................................B - 18

4.3 Troubleshooting Method...................................................................................................................B - 18

4.3.2 Troubleshooting Flow.......................................................................................................................B - 19

5. Connection Diagram...................................................................................................... B - 20

5.1 Interconnection Diagram ..................................................................................................................B - 20

5.2 PCB Layout ......................................................................................................................................B - 21

6. Parts List ........................................................................................................................ B - 22

APPENDIX C: MULTI FEEDER MAINTENANCE ............................................................. C - 1

Preface ...................................................................................................................................... C - 1

1. Outline ............................................................................................................................. C - 2

1.1 Functions.............................................................................................................................................C - 2

1.2 External View and Component Names ...............................................................................................C - 2

2. Mechanism Description................................................................................................... C - 3

2.1 General Mechanism ............................................................................................................................C - 3

2.2 Hopper Mechanism.............................................................................................................................C - 4

3. Parts Replacement ........................................................................................................... C - 5

3.1 Precautions Concerning Parts Replacement .......................................................................................C - 5

3.2 Parts Layout ........................................................................................................................................C - 7

3.3 Parts Replacement Methods ...............................................................................................................C - 8

3.3.1 Separator .............................................................................................................................................C - 9

3.3.2 AOLE-PCB.......................................................................................................................................C - 10

3.3.3 Square-shaped connector ..................................................................................................................C - 11

3.3.4 Hopping Motor .................................................................................................................................C - 12

3.3.5 Planet gear ........................................................................................................................................C - 13

3.3.6 Roller B.............................................................................................................................................C - 14

3.3.7 Roller A.............................................................................................................................................C - 15

3.3.8 Mini pitch belt & Feed roller ............................................................................................................C - 16

4. Troubleshooting............................................................................................................. C - 17

4.1 Precautions Prior to Troubleshooting ...............................................................................................C - 17

4.2 Preparations for Troubleshooting .....................................................................................................C - 17

4.3 Troubleshooting Method...................................................................................................................C - 17

4.3.1 LCD Status Message List .................................................................................................................C - 18

4.3.2 Troubleshooting Flow.......................................................................................................................C - 19

5. Connection Diagram...................................................................................................... C - 20

5.1 Interconnection Diagram ..................................................................................................................C - 20

5.2 PCB Layout ......................................................................................................................................C - 21

6. Parts List ........................................................................................................................ C - 22

APPENDIX D: LOCALTALK SERIAL INTERFACE (OKIPAGE16N/PS ONLY)........... D - 1

Table of Contents TOC - 4 OKIPAGE 16n

Service Manual, P/N 59274401

1. CONFIGURATION

AC IN

1.1 System Configuration

OKIPAGE16n / OKIPAGE16n/PS consists of control and engine blocks as the standard

configuration (See Figure 1-1.)

In addition, the following options are also available.

PC etc.

Centronics

Parallel interface

(Bidirection)

LocalTalk

(with PS model only)

Printer

Operator

Panel

Main control

Power/
Sensor

Board

DC Fan

Face down

stacker

Printer

Mechanism

I/D unit

LED head
Drum motor
Registration motor
Hopping motor

120V
230/240V

Face up

stacker

*

*

Toner Cartridge

Front Feeder

LAN etc.

OKI HSP

interface board

(Option)

Extension RAM

(Option)

PostScript

Board

(OKIPAGE16n/PS

only)

Paper tray

Paper size

detection switch

High Capacity
Second Paper

Feeder

(Option)

Multi Feeder

(Option)

*: Consumables

: Paper feeding
: Singal flow

Figure 1-1

Configuration 1 - 1 OKIPAGE 16n

Service Manual, P/N 59274401

1.2 Printer Configuration

The printer unit consists of the following hardware components:

• Electrophotographic processor

• Paper feeder

• Controller

• Operator panel

• Power Supply board
Figure 1-2 shows the printer unit configuration.

Figure 1-2

Configuration 1 - 2 OKIPAGE 16n

Service Manual, P/N 59274401

1.3 Optional Configuration

The options below are available for use with OKIPAGE16n / OKIPAGE16n/PS. They are sold

separately from the printer unit.

(1) Multi-Purpose Feeder

(2) High Capacity Second Paper Feeder

Configuration 1 - 3 OKIPAGE 16n

Service Manual, P/N 59274401

(3) RAM module (72 pin SIMM, 1 MB/2 MB/4 MB/8 MB/16 MB/32 MB)

• 16 MB RAM module

• 8 MB RAM module

Configuration 1 - 4 OKIPAGE 16n

Service Manual, P/N 59274401

1.4 Specification

(1) Type Desk top
(2) External dimensions Height 10.6” (270 mm)

(excludes protruding Width 14.4” (366 mm)

Portion) Depth 16.9” (430 mm)
(3) Weight 15.2 kg (33.5 lbs)
(4) Development method Dry electrophotography

Exposure method LED stationary head
(5) Paper used <Type>

• Standard paper
– Xerox 4200 (20 lbs)

• Application paper (manual face-up feed)
– Label
– Envelope
– OHP paper (Transparency)

<Size>

• Standard sizes
– Letter
– Legal
– Executive
– Envelope
–A4
–A5
–B5
–A6

• Applicable sizes
– Width: 3.4” to 8.5” (86 to 216 mm)
– Length: 5.5” to 14” (140 to 355.6 mm)

<Thickness>

– Automatic feed: 16 to 28 lbs (60 to 105 g/m
– Manual feed: Label, OHP paper (transparency)

Envelope

2

)

(6) Printing speed First print: 10 sec.

Continuous print: 16 sheets/min.
Warm-up time: 90 sec. [at room temperature 77˚F

(25˚C) and rated voltage (120 VAC)]
(7) Paper feed method Automatic feed or manual feed
(8) Paper delivery method Face down/face up
(9) Resolution 600 x 600 dots/inch
(10)Power input 120 VAC + 5.5%, –15%

230/240 VAC + 10%, –14%

Configuration 1 - 5 OKIPAGE 16n

Service Manual, P/N 59274401

(11)Power consumption Peak: Approx. 600W

(%)

Typical Operation: Approx. 220W
Idle: Approx. 100W
Power save mode: Approx. 20W

(12)Temperature and humidity

In operation Power off mode During Storage Unit

Temperature 50 - 90 32 - 110 14 - 110 °F

(10 - 32) (0 - 43) (–10 - 43) (°C)
Humidity
Maximum wet

bulb temperature
Minimum difference

of wet and dry
bulb temperatures

20 - 80 10 - 90 10 - 90 %RH

77 80.4 °F

(25) (26.8) (°C)

35.6 35.6 °F
(2) (2) (°C)

Notes:

1. Storage conditions specified above apply to printers in packed condition.

2. Temperature and humidity must be in the range where no condensation
occurs.

Temperature

(°C)

32

28

Operation range

10

20 80

Humidity

(13) Noise During operation: 50 dB (A) or less

At standby: 45 dB (A) or less
Power save mode: 43 dB (A) or less

(14)Consumables Toner cartridge kit 5,000 (5% duty)

Image drum cartridge 30,000 (at continuous printing)

18,000 (3 page/job)
11,000 (1 page/job)

Configuration 1 - 6 OKIPAGE 16n

Service Manual, P/N 59274401

1.5 Safety Standards

1.5.1 Certification Label
The safety certification label is affixed to the printer in the position below.

1.5.2 Warning Label
The warning label is affixed to the portion which may cause bodily injury.

Follow the instructions on warning labels during maintenance.

Configuration 1 - 7 OKIPAGE 16n

Service Manual, P/N 59274401

This page was intentionally left blank.

Configuration 1 - 8 OKIPAGE 16n

Service Manual, P/N 59274401

2. OPERATION DESCRIPTION

OKIPAGE16n / OKIPAGE16n/PS consists of a main control board, a power supply board, a driver
board, an operator panel and an electrophotographic process mechanism.

The control board receives data through a host I/F, decodes and edits the data, and stores the
edited data in memory. After completing edition of one page of data, it references the font memory
and generates bit data on the same memory. At the same time, it transfers the bit image data to
the LED head in units of one dot line.

The electrophotographic process mechanism prints data on paper.
The operator panel is used for operations and status display.
Fig. 2-1 shows an OKIPAGE16n / OKIPAGE16n/PS block diagram.

Operation Description 2 - 1 OKIPAGE 16n

Service Manual, P/N 59274401

*LocalTalk
Interface

Parallel
Interface

Z80181

Main
Control
Board
(BOARD­COM)

ROM

DS8925

SRAM

ROM

D RAM

SIMM

(Option)

7407

LS374

LS374

CPU

LSI

ROM

*PostScript Board

BOARD-PSBA

(option)

EEPROM

SW

EE
PROM

LED head
Operator panel
2nd tray

Envelope tray

(Option)

(Option)

Home micro switch

Stacker full sensor

Paper end sensor

AC-IN

OKI HSP
interface
(option)

Inlet sensor 1

Outlet sensor

Inlet sensor 2

Paper sensor

Paper out sensor

Toner sensor

Filter

circuit

+8V

-8V

0V

+30V

+5V

Low voltage

generation

circuit

LSI

Cover
open MS

Heat on

DRIVER

Relay/Drive Board

SW

DRIVER

DRIVER

DRIVER

High voltage
generation
circuit

(AOLC-PCB)

+5V

CH
TR

DB
SB

CB

M

AOLS-

M
M

FAN

TH1

TH2

Charge roller
Transfer roller
Developing roller
Toner supply roller
Cleaning roller

Hopping motor

Paper size
detection switch

Registration
motor

Drum motor

DC FAN

Thermistor

Power / Sensor board

Heat on

Driver

Heater

Figure 2-1 OKIPAGE16n / OKIPAGE16n/PS block diagram

Operation Description 2 - 2 OKIPAGE 16n

Service Manual, P/N 59274401

2.1 Main Control Board (BOARD-COM)

The control board consists of an one chip CPU, LSIs, program/font ROM's, DRAM's, an EEPROM,
a host interface circuit, and a mechanism driving circuit.

(1) One-chip CPU

The one-chip CPU is a custom CPU (32-bit internal bus, 32-bit external bus, 32-MHz clock)
that incorporates an RISC CPU and its peripheral devices, and has the following functions.

Built-in device Function

Chip select controller Control of ROM, DRAM and I/O device
Bus controller
DRAM controller

DMA controller Transfer of image data from DRAM to OST LSI

Parallel interface controller Control of Centronics parallel interface

Timer Generation of various control timing

Monitoring of paper running and paper size

Serial I/O port Control of operator panel, EEPROM, and options

I/O port Inputting/outputting of sensor, signal and motor signal

Option I/O interface Control of OKI HSP interface

(2) Program/font ROM's

The program/font ROM's store the HP IV emulation program and various types of font.
MASK ROM is used as the program/font ROM's.

Operation Description 2 - 3 OKIPAGE 16n

Service Manual, P/N 59274401

(3) DRAM's

2-Megabyte DRAM (4 Mbit DRAM x 4) is mounted as resident memory to be used for storing
the program and providing various buffers. This DRAM is expandable up to 66 Mbytes by
adding expansion memory (SIMMs). This DRAM provides the areas shown in the following
table.

Memory area Use Memory capacity setting

MENU Expansion RAM

System area Fixed Fixed

Raster buffer Enable Expandable

Receive buffer Enable Expandable

Page buffer – Expandable

DLL/macro buffer – Expandable

Font cache buffer Enable Expandable

Working area used for the program

Stores converted bit image data

Stores temporarily the data received
from the host interface

Adds print information to the analyzed
receive data and stores the resulted
data.

Stores soft fonts and macro data.

Stores bit map fonts generated by the
font rasterizer based on scalable font
information

(4) EEPROM

The EEPROM has a 1-kbit capacity and stores the following data.

• Menu data

• Various counter data (page counter, drum counter, fuser counter, etc.)

• Adjustment parameters (LED head drive time, print start position, etc.)

(5) LSI (MBCE31701-040FP-BND)

This LSI is used as a peripheral device of the CPU and performs smoothing compensation
(OST) of print image data. In addition, it transfers serially bit image data for each dot line to
the LED head.

(6) Host interface

This printer has the following interfaces to the host.

• Centronics bidirectional parallel interface

• OKI HSP interface (Option)

• LocalTalk interface (Option - PostScript Version)
The single effective interface or the automatic interface select mode can be selected using

the menu. If the busy state of the printer continues for a long time period, the buffer near­full control releases the busy status at constant intervals even if the host side is busy so not
to cause the interface time-out at the host side.

Operation Description 2 - 4 OKIPAGE 16n

Service Manual, P/N 59274401

(a) Centronics bidirectional parallel interface

This is an interface conforming to IEEE-1284 and provides either of unidirectional and
bidirectional communications according to each of the following communication modes.

• Compatibility mode
Unidirectional communications from the host to the printer.

• Nibble mode
This mode transmits 4-bit wide data from the printer to the host. In this mode, each
1-byte data is transferred in the form of two nibbles using ERROR, BUSY, FAULT,
and SELECT signal leads. This mode can provide the bidirectional operation in
combination with the compatibility mode.

• ECP mode
This mode provides the asynchronous bidirectional interface and transmits and
receives 1-byte data using eight data signal leads under the semi-duplex control by
the host.

When the power is turned on, the compatibility mode is automatically selected. The
change to another mode from the compatibility mode is made through negotiation.
(When the BI DIRECTION is set to ENABLE in the menu, this change can be performed.)
(For the electrical/physical characteristics of this interface, see APPENDIX A)

(b) OKI HSP interface (Option)

This interface (slot) is an OKI unique universal interface that provides the platform to
connect various boards (such as the LAN connection expansion board and SCSI
expansion board).
Any expansion boards compatible with this interface can be mounted on the Control
board in the piggyback board without modifying the program at the printer side. The
conceptual diagram of the OKI HSP interface is shown in Fig. 2-2.

Printer

Network, etc.

Control board

OKI HSP

interface

LAN

expansion board

Fig. 2-2

Operation Description 2 - 5 OKIPAGE 16n

Service Manual, P/N 59274401

(7) RAM module

1363772

• Pin layout

• Basic specification

- Type: 72 pins SIIM (32 bits buss width)

- Access time: 60ns, 70ns, 80ns, 100ns

- Capacity: 1, 2, 4, 8, 16 or 32MB

- Parity: None

Operation Description 2 - 6 OKIPAGE 16n

Service Manual, P/N 59274401

2.2 Power Supply Board

The power supply board consists of an AC filter circuit, a low voltage power supply circuit, a high
voltage power supply circuit, heater drive circuit, and photosensors.

(1) Low voltage power supply circuit

This circuit generates the following voltages.

Output voltage Use

+5 V Logic circuit supply voltage

+30 V Motor and fan drive voltage and source voltage for high-voltage supply

+8 V Reset circuit

–8 V Local Talk Line voltage

(2) High voltage power supply circuit

This circuit generates the following voltages necessary for electrophotographic processing
from +30 V according to the control sequence from the control board. When cover open state
is detected, +30 V supply is automatically interrupted to stop the supply of all the high-voltage
outputs.

Output Voltage Use Remarks

CH -1.30 KV Voltage applied to charging roller

DB -240 V/+300 V Voltage applied to developing roller

SB -360 V/450 V Voltage applied to toner supply roller

TR +4 KV/-1.3 kV Voltage applied to transfer roller Variable

CB +400 V Voltage applied to cleaning roller

(3) Photosensor

The photosensor mounted on this power supply board supervises the paper running state
during printing.

Operation Description 2 - 7 OKIPAGE 16n

Service Manual, P/N 59274401

Paper running direction

Figure 2-3 shows the sensor layout diagram.

Exit roller

Outlet sensor

Heat roller

Transfer roller

Sensor

Inlet sensor 1

Inlet sensor 2

Toner sensor

Inlet sensor 1

Inlet sensor 2

Paper sensor

Registration roller

Paper end sensor

Hopping

roller

Figure 2-3

Function

Detects the leading part of the paper and gives the supervision
timing for switching from hopping operation to feeding opera­tion.
Supervises the paper running state and the paper size accord­ing to the paper reach time and running time.

Detects the form width.

Sensing state

ON: Paper exists.
OFF: No paper exists.

ON: A4 or larger
OFF: Smaller than A4

Paper sensor

Outlet sensor

Paper end sensor

Toner low sensor

Detects the leading part of the paper.
Supervises the paper running state.

Supervises the paper feed and size according to the time of
arrival to the sensor and the time of passage of paper.

Detect the end of the paper.

Detects the lack of toner.

ON: Paper exists.
OFF: No paper exists.

ON: Paper exists.
OFF: No paper exists.

ON: Paper exists.
OFF: No paper exists.

ON long: Toner low exists
OFF short: No Toner low exists

Operation Description 2 - 8 OKIPAGE 16n

Service Manual, P/N 59274401

2.3 Relay/Driver Board (AOLC board)

This board relays signals between the Control board and the Power supply board and includes
the registration motor and drum motor driver IC.

Operation Description 2 - 9 OKIPAGE 16n

Service Manual, P/N 59274401

2.4 Electrophotographic Process

2.4.1 Electrophotographic process mechanism
This mechanism prints image data from the control board on the paper by electrophotographic

process.

The Figure 2-4 shows the layout of the electrophotographic process mechanism.

Front Feeder

Hopping Roller

Hopping Motor

Registration Motor

LED Head

Fuser

Face Up

Stacker

Drum Motor

Image Drum Unit

Figure 2-4

Operation Description 2 - 10 OKIPAGE 16n

Service Manual, P/N 59274401

(1) Image drum unit

The image drum unit consists of a sensitive drum, a charger, and a developer. The unit forms
a toner image on the sensitive drum, using a electrostatic latent image formed by the LED
head.

(2) Hopping motor

This motor is a pulse motor of 48 steps/rotation that is two-phase excited by the signal from
the control board. It drives the hopping roller of the first tray and the front feed roller via two
one-way clutches according to the direction of rotation.

(3) Registration motor

This motor is a pulse motor of 48 steps/rotation that is two-phase excited by the signal from
the control board. It drives the registration roller.

(4) Drum motor

This drum motor is a pulse motor of 48 steps/rotation that is two-phase excited by the signal
from the control board and is the main motor of this mechanism.

(5) LED head

Image data for each dot line from the control board is received by the shift register and latch
register. The 4992 LEDs are driven to radiate the image data to the image drum.

(6) Fuser

The fuser consists of a heater, a heat roller, a thermistor and a thermostat.
An AC voltage from the power supply board is applied to the heater under the control of the
HEATON signal from the control board. This AC voltage heats the heater. The control board
supervises the heat roller temperature via the thermistor, and regulates the heater roller at
a predetermined temperature (185 ~ 188°C) by connecting or disconnecting the AC voltage
supply to the heater.
If the heater roller temperature rises abnormally, the thermostat of the heater voltage supply
circuit is activated to cut the AC voltage supply immediately.

Operation Description 2 - 11 OKIPAGE 16n

Service Manual, P/N 59274401

2.4.2 Electrophotographic process
The electrophotographic processing is outlined below. Figure 2-5 shows the electrophotographic

printing process.

1 Charging

The surface of the image drum is uniformly charged with negative charges by applying a
negative voltage to the charge roller.

2 Exposure

Light emitted from the LED head irradiates the negatively charged surface of the image drum.
The surface potential of the irradiated part of the image drum surface is lowered, so that an
electrostatic latent image associated with the print image is formed.

3 Developing and toner recovery

When the negatively charged toner is brought into contact with the image drum, it is attracted
to the electrostatic latent image by static electricity, making the image visible.
At the same time, the residual toner on the image drum is attracted to the developing roller
by static electricity.

4 Transfer

When paper is placed over the image drum surface and a positive charge, opposite in polarity
to the toner, is applied to the reverse side of the paper from the transfer roller, the toner is
attracted by the positive charge and is transferred to the paper. As a result, the toner image
formed on the image drum is transferred to the paper.

5 Temporary cleaning

Residual toner that remains on the image drum without being transferred is made uniform
by the cleaning roller and is temporarily attracted to the cleaning roller by static electricity.

6 Fusing

The toner image transferred to the paper is fused under heat and pressure.
Figure 2-6 shows an electrophotographic process timing chart.

Operation Description 2 - 12 OKIPAGE 16n

Service Manual, P/N 59274401

Operation Description 2 - 13 OKIPAGE 16n

Paper

eject

roller

Paper

eject

(Face down)

Power
supply

Charger

roller

Image data

LED head

Figure 2-5

Paper

eject

roller

Paper

eject

(Face up)

Service Manual, P/N 59274401

Power
supply

Charging

Paper

path

selector

Outlet sensor

Heater roller

Paper eject Fusing Cleaning Transfer

Fusing

Cleaning

roller

Fusing pressure

Cleaning

Power
supply

Exposure

Transfer

Transfer

roller

Power
supply

(Bias voltage)

Developing

Paper sensor

Image
production
developing Paper feed Paper hopping

Developing

roller

Inlet sensor

Paper

registration

Registration

roller

Doctor

blade

Paper
supply

Hopping

roller

Path of paper
feeding

Direction of
rotation of the
image drum

Toner

supply roller

Front

feeder

Toner

cartridge

RMON-N

RMON-N

DMON-N

INSNS

WRSNS

OUTSNS

LEDSTB

IN Sensor OFF Paper Sensor

OFF

Feed StopOut Sensor

OFF

Feed start

Figure 2-6

Operation Description 2 - 14 OKIPAGE 16n

Service Manual, P/N 59274401

2.4.3 Process operation descriptions
(1) Hopping

Feeding from the first tray and the front feeder are effected by a single hopping motor in the
mechanism shown below.

Turning the Hopping motor in the “a” direction drives the hopping roller of the first tray.
Turning the Hopping motor in the “b” direction drives the Hopping roller of the front feeder.
Both hopping gears contain one-way bearings, so that turning each of these gears in reverse
direction will not be transmitted to the corresponding roller.

a

One-way Clutch

Gear B

b

Hopping Roller
(Front Feeder)

Hopping Motor

Registration Roller

Hopping Roller

(First Tray)

One-way

Clutch Gear A

Operation Description 2 - 15 OKIPAGE 16n

Service Manual, P/N 59274401