OKI OL810e Service manual

Chapter 1
Front Cover

OKIDATA

OL810e LED PAGE PRINTER
Service Manual

ODA P/N: 59270001

Manual Copyright

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

Chapter 1
%1.1 System Configuration

1.1 System Configuration

OL810e consists of control and engine blocks in the standard configuration, as shown in Figure 1-1.
In addition, the options marked with asterisk(*) are available.

Figure 1-1

Note: Power Envelope Feeder is compatible with OL400e series printers.

%1.2 Printer Configuration

1.2 Printer Configuration

The printer unit consists of the following hardware components:

• Electrophotographic Processor

• Paper Feeder

• Controller

• Operator Panel

• Power Supply Unit
The printer unit configuration is shown in Figure 1-2.

%1.3 Options available for use with OL810e

1.3 Optional Configuration

The options shown below are available for use with OL810e. These are available separately from
the printer unit.
(1) Memory Expansion Board (1MB to 32MB)

(2) SIMM Memory SIMM memory is available with memory of 1MB (min.) to 16MB (max.). The
access time of SIMM memories are 60ns, 70ns, 80ns, and 100ns.

(3) IC Card

(4) Universal Paper Cassette

(5) High Capacity Second Paper Feeder

(6) Power Envelope Feeder

%1.4 Specification

1.4 Specification
(1) Type Desktop
(2) External dimensions Height 7.9 (200 mm) (excludes protruding Width 12.8 (370 mm)

portion) Depth 14.6 (370 mm)
(3) Weight 10 kg
(4) Developing method Dry electrophotography Exposing 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 CON-10 Monarch DL C5 COM-9 Envelope A4

A5 B5 (JIS) A6

• Applicable sizes Width: 3.87 to 8.5 (116 to 216 mm) Length: 5.83 to 14 (148 to 355.6 mm)
<Thickness> Automatic feed: 16 to 36 lbs (60 to 135 g/m 2 ) Manual feed: Label, OHP paper

(transparency) Envelope
(6) Printing speed First print: 25 sec. Continuous print: 8 sheets/min. for letter size paper

Warm-up time: 60 sec. [at room temperature 77°F (25°C) and rated voltage (120 VAC)]
(7) Paper feeding 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 VAC + 6%, -14% 230 VAC + 10%, -10%
(11)Power consumption Peak: Approx. 600W Typical operation: Approx. 130W Idle: Approx.

41W Power save mode: Approx. 13W
(12)Temperature and humidity During operation: 50 to 90°F (10 to 32°C) In storage: -14 to

112°F (-20 to 50°C)
(13) Noise During operation: 48 dB (A) or less Standby: 36 dB (A) or less Quiet mode: 32 dB

(A) or less
(14)Consumables Toner cartridge kit 2,000 (5% duty) Image drum cartridge 20,000 (at

continuous printing) 15,000 (3 page/job) 10,000 (1 page/job)

%1.5 Safety Standards - Certification & Warning Labels

1.5 Safety Standards

1.5.1 Certification Label
The safety certification and serial number labels are affixed to the printer in the positions
described below.

1.5.2 Warning Label

The warning labels are affixed to the sections which may cause bodily injury.
Follow the instructions on warning labels during maintenance.

%1.5.3 Warning/Caution Marking

1.5.3 Warning/Caution Marking
The following warning and caution markings are made on the power supply/sensor board.

ENGLISH Heatsink and transformer core present risk of electric shock. Test before touching.
FRENCH Le dissipateur thermique et le noyau du transformateur présentent des risques de choc
électrique. Testez avant de manipuler.
SPANISH Las disipadores de color el núcel del transformador pueden producir un choque
eléctrico. Compruebe antes de tocar. PORTUGUESE O dissipador de calor e o núcleo do
fransiormador apresentam risco de choque elétrico. Teste antes de focar.
ENGLISH Circuits maybe live after fuses open.
FRENCH Il se peut que les circuits soient sous tension une fois que les fusibles ont éfé rerirés.
SPANISH Las circuitos pueden estar activos una vez que se hayan abierio los fusibles.
PORTUGUESE Os circuitos podem estar energizados após os fusiveis se queimarem.*

Chapter 2
%Operation Description

2. OPERATION DESCRIPTION

OL810e consists of a main control board, a power supply/sensor board, an operator panel, an
electrophotographic process mechanism, and revision for illumination of LED head.
The main control board receives data via the host I/F, it then decodes, edits and stores the data in
memory. After completing the editing of a single page of data, it references the font memory and
generates bit image data, which is transferred to the LED head in one dot line units.
Through the electrophotographic process mechanism, the data is printed on the paper.
The operator panel is used for operations and status display.
OL810e block diagram is shown in Figure 2-1.

%2.1 Main Control Board

2.1 Main Control Board
The main control board consists of a single chip CPU, a program ROM, a font ROM, four DRAMs, an
EEPROM, a host interface circuit, and a mechanism driving circuit.
(1) Single chip CPU
The single chip CPU is a custom CPU (32-bit internal bus, 32-bit external bus, 25.54-MHz clock, with
input frequency from a 12.27-MHz clock) which incorporates the RISC CPU and its peripheral devices,
and has the following functions:

Built-in device

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

DMA controller Transfer of image data from DRAM to video output port
Parallel interface controller Control of Centronics parallel interface
Serial interface controller Control of RS-232C serial interface
Video output port Control of LED head

LED STB output port
Timer Generation of various control timing

Serial I/O port Control of operator panel, EEPROM, and options
I/O port Input and output of sensor and motor signals
(2) Program and Font ROMs

The Program and Font ROMs store the equipment program and various types of fonts. EPROM or Mask
ROM is used as Program and Font ROMs. The mounting locations of these Program and Font ROMs
vary depending on the type of the ROMs (for the mounting location see Section 7.4).

Function

Monitoring of paper running and paper size

(3) DRAM
The DRAM is a 2MB resident memory which is used as a buffer, that stores edited data, image data, DLL
data and macro data.

(4) EEPROM
1,024-bit Electrically Erasable PROM (EEPROM), is loaded with the following kinds of data:

• Menu data • Various counter data (page counter, drum counter) • Adjusting parameters (LED head drive
time, print start position, paper feed length)

(5) Parallel Interface
Parallel data is received from a host system via parallel interface which conforms to the Centronics
specification.

(6) RS232C Serial Interface
Serial data is sent to and received from a host system via serial interface which conforms to EIA
RS232C.
Following items are selectable:
Flow control: DTR HI/DTR LO/XONXOFF/RBSTXON Baud rate: 300/600/1200/2400/4800/9600/19200
Data bits: 7 BITS/8 BITS Parity: NONE/EVEN/0DD Minimum busy: 200 mSEC/1 SEC

%2.2 Power Supply/Sensor Board

2.2 Power Supply/Sensor Board

The power supply/sensor 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 RS-232C line voltage
8 V RS-232C line voltage and PS board supply voltage
+3.3V LED head supply voltage

(2) High Voltage Power Supply Circuit

This circuit generates the following voltages required for electrophotographic process from +5 V,
according to the control sequence from the main control board. When cover open state is detected, +5 V
supply is interrupted automatically to stop the supply of all high-voltage outputs.

Output

CH -1.35 KV Voltage applied to charging roller
DB -300 V/+300 V Voltage applied to developing roller
SB -450 V/ 0 V Voltage applied to toner supply roller
TR +500 V to +4 KV/-750 V Voltage applied to transfer roller Variable
CB +400 V Voltage applied to clearing roller

(3) Photosensor
The photosensor mounted on this power supply/sensor board monitors the status of paper being fed
through the printer during printing.

The sensor layout diagram is shown in Figure 2-2.

Voltage Use Remarks

Function Sensing state

Inlet sensor 1 Detects the leading part of the

paper and gives the monitor
timing for switching from
hopping operation to feeding
operation. Monitors paper
feeding situation and paper
size based on the paper
arrival time and running time.

Intel sensor 2 Detects the paper width. ON: A4 or larger OFF:

Paper sensor Detects the leading portion of

the paper. Monitors the paper
feeding situation.

Outlet sensor Monitors the paper feeding

and size according to the time
of arrival to and leaving past
the sensor.

Paper end sensor Detects the end of the paper. ON: Paper exists. OFF: No

Toner low sensor Detects the lack of

toner.Sensor

ON: Paper exists. OFF: No
paper exists.

Smaller than A4
ON: Paper exists. OFF: No

paper exists.

ON: Paper exists. OFF: No
paper exists.

paper exists.

- - - - -

%2.3 Electrophotographic Process

2.3 Electrophotographic Process

2.3.1 Electrophotographic Process Mechanism
This mechanism actuates the printing of image data supplied by the main control board on the paper by
electrophotographic process.
The layout of the electrophotographic process mechanism is shown in Figure 2-3.

(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) Registration Motor

The registration motor is a pulse motor of 48 steps/rotation with two-phase excitement by the signal from
the main control board. It drives the hopping and registration rollers via two one-way clutches according
to the direction of rotation.

(3) Main (Drum) Motor

The main or drum motor is a pulse motor of 48 steps/rotation with two-phase excitement by the signal
from the main control board and is the main motor of this mechanism.

(4) LED Head

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

(5) Fuser

The fuser consists of a heater, a heat roller, a thermistor and a thermostat.
The AC voltage from the power supply/sensor board is applied to the heater controlled by the HEATON
signal from the main control board. This AC voltage heats the heater. The main control board monitors
the heat roller temperature via the thermistor, and regulates the heater roller to keep it at a designated
temperature in the menu, depending on the thickness of the paper (tray 1&2: light=165°C, medium
light=170°C, medium=175°C, medium heavy and heavy=195°C; manual feeding and power envelope
feeder: light=175°C, medium light=180°C, medium=185°C, medium heavy=190°C, heavy=195°C) by
connecting or disconnecting the AC voltage supply to the heater.
When an abnormal rise of the heater roller temperature takes place, the thermostat of the heater voltage

supply circuit becomes active and forcibly cuts the AC voltage supply.
The temperature setting of the fuser can be changed through operator panel setting.

%2.3.2 Electrophotographic Process

2.3.2 Electrophotographic Process

The electrophotographic processing is outlined below. The electrophotographic printing process is shown
in Figure 2-4.

1 Charging

The surface of the image drum is charged uniformly with a negative charge by applying the 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 portion of the image drum surface becomes lower, forming the
electrostatic latent image associated with the print image.

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, the positive charge which is opposite in polarity to
that of the toner, is applied to the reverse side of the paper by the transfer roller. The toner is attracted by
the positive charge and is transferred onto the paper. This results in the transfer of the toner image
formed on the image drum onto the paper.

5 Temporary cleaning

Residual toner which remains on the image drum without being transferred is evened out by the cleaning
roller and is temporarily attracted to the cleaning roller by static electricity.

6 Fusing

The toner image transferred onto the paper is fused to the paper by heat and pressure.
An electrophotographic process timing chart is shown in Figure 2-5.

%2.3.3 Process Operation Descriptions

2.3.3 Process Operation Descriptions

(1) Hopping and Feeding

Hopping and feeding motions are actuated by a single registration motor in the mechanism as shown
below:

The registration motor turning in direction "a" drives the hopping roller. The registration motor turning in
direction "b" drives the registration roller. The registration and hopping gears have one-way bearing, so
turning any of these gears in the reverse direction will not transmit the motion to the corresponding roller.

(a) Hopping
1 For hopping, the registration motor turns in direction "a" (clockwise direction) and drives the hopping
roller to advance the paper until the inlet sensor turns on (in this case, the registration gear also turns, but
the registration roller is pre-vented from turning by the one-way bearing).
2 After inlet sensor is turned on by the paper advance, the paper is further ad-vanced to a predetermined
distance until the paper hits the registration roller (the skew of the paper can thus be corrected).

(b) Feeding
1 When hopping is completed, the registration motor turning in direction "b" (counter-clockwise direction)
drives the registration roller to advance the paper (in this case, the hopping gear also turns, but the
hopping roller is prevented from turning by the one-way bearing).

2 The paper is further advanced in synchronization with the print data.

(2) Charging
Charging is actuated by the application of the DC voltage to the charge roller that is in contact with the
image drum surface.

The charge roller is composed of two layers, a conductive layer and a surface protective layer, both
having elasticity to secure good contact with the image drum. When the DC voltage applied by the power
supply exceeds the threshold value, charging begins. The applied voltage is proportional to the charge
potential, with offset of approximately 550V.

(3) Exposure
Light emitted by the LED head irradiates the image drum surface with a negative charge. The surface
potential of the irradiated portion of the image drum drops, forming an electrostatic latent image
associated with the image signal.

The image drum is coated with an underlayer (UL), a carrier generation layer (CGL), and carrier transfer
layer (CTL) on aluminum base. The organic photo conductor layer (OPC), comprising CTL and CGL, is
about 20 µm thick.

The image roller surface is charged to about 750 V by the contact charge of the charge roller.
When the light from the LED head irradiates the image drum surface, the light energy generates positive
and negative carriers in the CGL. The positive carriers are moved to the CTL by an electrical field acting
on the image drum. Likewise, the negative carriers flow into the aluminum layer (ground).

The positive carriers moved to the CTL combine with the negative charges on the image drum surface
accumulated by the contact charge of the charge roller, lowering the potential on the image drum surface.
The resultant drop in the potential of the irradiated portion of the image drum surface forms an
electrostatic latent image on it. The irradiated portion of the image drum surface is kept to about 100 V.

(4) Developing
Toner is attracted to the electrostatic latent image on the image drum surface, converting it into a visible
toner image. Developing takes place through the contact between the image drum and the developing
roller.

1 As the toner supply roller rotates while rubbing on the developing roller, a friction charge is generated
between the developing roller and the toner, allowing the toner to be attracted to the developing roller (the
developing roller surface is charged positive and the toner, negative).

2 The toner attracted to the developing roller is scraped off by the doctor blade, forming a thin coat of
toner on the developing roller surface.
3 Toner is attracted to the exposed portion (low-potential part) of the image drum at the contact of the
image drum and the developing roller, making the electrostatic latent image visible.

Note: The bias voltage required during the developing process is supplied to the toner supply roller and
the developing roller, as shown below. 450 VDC is supplied to the toner supply roller, 300 VDC to the
developing roller.

(5) Transfer
The transfer roller is composed of conductive sponge material, and is designed to get the image drum
surface and the paper in a close contact.
Paper is placed over the image drum surface, and the positive charge, opposite in polarity to that of the
toner, is applied to the paper from the reverse side.
The application of a high positive voltage from the power supply to the transfer roller causes the positive
charge inducement on the transfer roller surface, transferring the charge to the paper as it contacts the
transfer roller. The toner with negative charge is attracted to the image drum surface, and it is transferred
to the upper side of the paper due to the positive charge on the reverse side of the paper.

(6) Fusing
When the transfer is completed, the toner image is fused to the paper by heat and pressure as the paper
with unfused toner image passes between the heater roller and the back-up roller. The heater roller with
Teflon coating incorporates a 400W heater (Halogen lamp), which generates heat.
A thermistor which is in contact with the heater roller regulates the temperature of the heater roller to a
designated temperature in the menu, depending on the thickness of the paper (tray 1&2: light=165°C,
medium light=170°C, medium=175°C, medium heavy and heavy=195°C/ manual feeding and power
envelope feeder: light=175°C, medium light=180°C, medium=185°C, midium heavy=190°C,
heavy=195°C). A safety thermostat cuts voltage supply to the heater off by opening the thermostat in the
event of abnormal temperature rises.
The back-up roller is held under a pressure of 7.52 kg applied by the pressure spring on each side.

(7) Cleaning
When the transfer is completed, the residual toner left on the image drum is attracted to the cleaning
roller temporarily by static electricity, and the image drum surface is cleaned.

(8) Cleaning of rollers
The charge, transfer and cleaning rollers are cleaned for the following cases:

• Warming up when the power is turned on. • Warming up after the opening and closing of the cover. •
When the number of sheets accumulated reaches 10 or more, and the printout operation ends.
Changes in bias voltage applied to each roller move the attaching toner off the roller to the image drum
and return it to the developer.

%2.3.4 Revision of LED Head Illumination

2.3.4 Revision of LED Head Illumination
An LED correcting head, which is capable of correcting the illumination of the LED for each dot, is being
used in this printer. LED illumination correction function of 16 steps is carried out by using an EEPROM
which is installed in the LSI that maintains the LED illumination correction values, and an LED correction
drivers (MSM6731BWAF) together as a pair.
The LED correcting head consists of the correction control LSI (MSM6730WAF), LED drivers
(MSM6731BWAF), and an LED array. The block diagram of the LED correcting head is shown below.

The existing LED head receives the printing data from the CPU directly at its LED drivers. With the LED
correcting head, a correction control LSI (MSM6730WAF) is connected between the CPU and LED
drivers, so the printing data is input to the LED drivers through the correction control LSI. In order to
maintain compatibility with the existing LED head, the printing operation of the LED correcting head is
carried out through identical sequence.

The LED correcting head is a 600 dpi head, with the LED drivers located on both sides of the LED array
with a 300 dpi pitch spacing. The printing and correction data obtained from the CPU through four signal
lines are sent to the LED array.

The printing operation timing chart is shown below.

The printing operation is carried out in normal mode. Under ordinary circumstances such as when the
power is turned on or when LOADI signal level is low, the normal mode is enabled.
The printing operation is carried out in the following sequence. First, the printing data DATAI3 through
DATAI0 are stored, sequentially shifted, in the shift registers of the LED drivers, by the printing data

synchronous clock, CLOCKI. Then the printing data stored in shift registers are latched by the high level
pulse of LOADI. The latched printing data turns the LEDs on by STRB1I-N through STRB4I-N and
actuates printing.

The mode setting timing chart during illumination correction is shown below.

The mode setting is carried out in the following manner. LOADI is fixed at high level, and DATAI0 which
comes up following this is 4-data latched with the timing of the fall of CLOCKI. The illumination correction
mode is selected based on the latched 4-data combination. Then the mode becomes valid at the fifth fall
of CLOCKI.

The period during which the illumination correction mode is valid is from the fall of the fifth CLOCKI and
while the level of LOADI is high. When the level of LOADI becomes low, the illumination correction mode
is terminated, and the head returns to the normal mode, which is mode with which the printing is normally
carried out.

The LED driver (MSM6731BWAF) corrects the LED illumination by controlling the LED current. The LED
illumination can be set in 16 steps, with 7 steps in the direction of illumination increase in relation to the
standard value, and 8 steps in the direction of decrease. For this reason, the LED correction data is a
4-bit data for each dot.

The relationship between the LED correction data and LED current correction steps with the LED driver
(MSM6731BWAF) used in an LED head is shown below.

%2.4 Paper Jam Detection

2.4 Paper Jam Detection
The paper jam detection function monitors the paper condition when the power is turned on and during
printing. When any of the following conditions arises, this function interrupts the printing process. If any of
the following errors is encountered, printing can be recovered by removing the jammed paper (by opening
the upper cover, removing the jammed paper and closing the upper cover).

Error Cause of error
Paper input jam - The paper is in contact with the inlet sensor when the

power is turned on.

- After hopping operation is attempted three times, the
leading edge of the paper does not reach the inlet sensor.

Paper feed jam - The paper is in contact with the paper sensor when the

power is turned on.

- The leading edge of the paper does not reach the paper
sensor within a predetermined feeding distance since the
paper has reached the inlet sensor.

- The trailing edge of the paper does not pass over the
paper sensor within a predetermined feeding distance after
the same has passed over the inlet sensor.

- The leading edge of paper does not reach the outlet
sensor within a predeter-mined feeding distance after the
paper has reached the paper sensor.

Paper exit jam - The paper is in contact with the outlet sensor when the

power is turned on.

- The paper does not pass over the outlet sensor within a
predetermined feeding distance after the leading edge of
the paper has reached the outlet sensor.

- The paper size check for manual feeding finds that the
paper size is free size.

Paper size error Paper size error - The size of the paper is monitored by the

inlet sensor 1. The paper is not detected by the inlet sensor
1 within predetermined feeding distance.

- The inlet sensor 2 detects that the size of the loaded
paper is A4 or larger, or smaller than A4. The detected
paper size differs from the paper size set by command or
menu.

- The paper size check for manual feeding finds that the
paper size is free size.

Paper Feed Check List

ERROR
Type of error Monitor Standard value Pluse Minus
Paper feed

error

Paper feed jam In sensor on

Paper feed jam Write sensor on

Paper size error In sensor on

Paper exit jam Out sensor on

Paper feed jam In sensor off

Note: Hyphen "-" in the table represents "not checked."Paper Length List

Hopping start
to
In sensor on

to
Write sensor on

to
Out sensor on

to
Out sensor on

to
Out sensor off

to
Write sensor off

72.0 36.0 _

20.0 20.0 _

138.0 69.0 _

Depends on the paper
length

Depends on the paper
length

22.0 22.0 -

45.0 45.0

45.0 45.0

Unit : mm

Type Paper length Min. Max.
A4 297.0 252.0 342.0
A5 210.0 165.0 255.0
B5 257.0 212.0 302.0

Check range

LETTER 279.4 234.4 324.4
LEGAL 13 330.2 285.2 400.6
LEGAL 14 355.6 285.2 400.6
EXEC 266.7 221.7 311.7
A6 148.0 103.0 193.0
Monarch 190.5 145.5 235.5
COM-9 225.4 180.4 270.4
COM-10 241.3 196.3 286.3
DL 220.0 175.0 265.0
C5 229.0 184.0 274.0
Free 148.0 ~ 355.6 103.0 400.6

Unit : mm