This Maintenance Manual describes the field maintenance methods for LED Page Printers.
This manual is written for use by service persons. Please note that you should refer to the Printer
Handbook for the handling and operating methods of the equipment.
77 ˚F (25 ˚C))
(7) Paper feeding methodAutomatic paper feed or manual paper feed
(8) Paper delivery methodFace up
(9) Resolution600 dpi x 600 dpi
(10)Power input230 VAC ±10% (for OEL)
120 VAC +6%, -15% (for ODA)
(11)Power consumption
Peak:Approx. 450W
Typical operation:Approx. 160W
Idle:Approx. 32W
Power save mode:Approx.6W
41260201TH Draft 8 /106
(12)Temperature and humidity
During operation
In storage
Caution:
Temperature and humidity in storage are measured with the OKIPAGE 8iM being
Temperature
10 to 32 ˚C
–10 to +43 ˚C
20 to 80% RH (relative humidity)
10 to 90% RH (relative humidity)
No condensation is permissible.
Humidity
packed; they are valid for one year.
(13)NoiseDuring operation: Avg. 50 dB (A), slow (without peak sounds)
1.4.1Certification Label
The safety certification label is affixed to the following location of the OKIPAGE 8iM
1.4.2Warning Label
Warning labels are affixed to the locations that may cause bodily injury.
During maintenance, do work with enough care while following instructions on these warning
labels.
For OEL
For ODA, OEL
41260201TH Draft 10 /106
2.OPERATION DESCRIPTION
The OKIPAGE 8iM consists of a main control board, two high-voltage power supply board, a power
supply unit, and an electro-photographic processor. The OKIPAGE 8iM receives print data from
a higher-level interface and sequentially stores it in memory. The OKIPAGE 8iM decodes and
edits the received data while storing print data from the interface in memory. It sequentially
transfers the edited data to the LED head for each dot line. The electro-photographic processor
then prints the data on sheets of paper.
The display of the higher-level host is used for device operation and status display.
Figure 2-1 is the block diagram of the OKIPAGE 8iM.
41260201TH Draft 11/106
PLUNGERLED HEAD
Motor
USB
I/F
USB
Printer
Cable
Parallel
I/F
Macintosh
I/F
CN4
CN5
LS07
DS8925
+5V+26V
HEAD2HEAD1CN8
CN2
CN7
0V5V
0VP0V
Motor Driver
MTD2005F
CPU
(nX8)
DRAM Bus
(Data : 4)
(Address : 11)
OSC
16MHz
RST
EEPROM
1kb
EPROM
64KB
LS373
Serial I/F
DRAM
2MB
HC125
CN10CN1
Power Supply Unit
Figure 2-1 Block Diagram
High Voltage Power Unit
P2H
ID Unit
High Voltage Power Unit
P6L
41260201TH Draft 12 /106
2.1Main Control Board
The main control board consists of a one-chip CPU, a program ROM, a DRAM, an EEPROM, a
host interface circuit, and a mechanism driving circuit. The mechanism driving circuit consists of
a LED head, a main motor, and an electromagnetic clutch.
(1) One-chip CPU
The one-chip CPU is a custom CPU (8-bit internal bus, 8-bit external bus, 16-MHz clock)
incorporating mask ROM and CPU peripheral devices. This CPU has the functions listed in
the table below.
Built-in DeviceFunction
DRAM controller
DMA controller
Parallel interface controller
Video output port
LED STB output port
Timer
I/O port
A/D converter
Controls DRAM.
Transfers image data from Parallel I/F to DRAM, from DRAM to a video output port and
between CPU and DRAM.
Controls the parallel interface.
Controls LED head.
Generates various control timings for monitoring paper feeding and a paper size.
Inputs and outputs the sensor signals and motor signals, etc.
Also performs I/O for EEPROM.
Inputs the feedback signals from a high-voltage generation circuit and thermistor signal.
(2) Program ROM
Program ROM contains a program for the equipment. EPROM is used as program ROM.
For details PCB Layout see Section 7.2.2.
(3) DRAM
DRAM is used as resident memory.
(4) EEPROM
EEPROM holds the following data:
• Menu data
• Counter value
• Adjustment value
(5) Parallel interface
The parallel interface receives parallel data from the host; it conforms to the Centronics
specification. IEEE-1284 B: – directional parallel is supported.
(6) Macintosh interface
Macintosh interface receives serial data from the host.
41260201TH Draft 13 /106
2.2Power Supply Unit
The power supply unit supplies +5 V and +26 V to the main control board according to 230 VAC /
120 VAC.
Output voltageApplication
+5 V
+26V
Used to generate a logic circuit and a high voltage.
Used to drive the motor and electromagnetic clutch.
The power supply unit also contains a heater drive circuit.
2.3High-Voltage Power Supply Board
(1) High-Voltage power supply circuit
The high-voltage power supply circuit generates the following voltages required for the
electro-photographic processor from +5 V according to the control sequence from the main
control board. When the cover is open, +5 V supply is automatically interrupted to stop highvoltage output.
OutputApplication
CH
–1.3 KV
DB
–265 V/+265 V
SB
–550 V/ 0 V
CB
+400 V/–1.35 KV
TR
+500 V ~ +3.5 KV/–750 V
Voltage
Voltage to be applied to a charge roller.
Voltage to be applied to a developing roller.
Voltage to be applied to a sponge roller.
Voltage to be applied to a cleaning roller.
Voltage to be applied to a transfer roller.
Remarks
P2H-PCB
P2H-PCB
P2H-PCB
P6L-PCB
P2H-PCB
Caution:
The TR voltage varies with medium and transfer roller impedance.
41260201TH Draft 14 /106
(2) Sensors
The high-voltage power supply board consists of the high-voltage power supply circuit that
supplies power to the electro-photographic processor system and the photosensor that
detects a paper feeding system and toners.
Figure 2-2 shows the sensor layout drawing.
Exit roller
Outlet sensor
Heat roller
Transfer roller
Paper sensor
Toner
sensor
assy
Manual feed sensor
Paper feeding direction
Feed roller
Hopping
roller
Figure 2-2
SensorFunctionSensing State
Manual feed
sensor
Paper sensor
Outlet sensor
Toner sensor
Monitors whether paper was inserted into the manual feed sensor
section.
Detects the leading part of the paper.
Monitors paper feeding.
Monitors paper feeding and the paper size according to the paper
sensor arrival and passing time.
Detects the low toner status.
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
OFF (short): Toner High
41260201TH Draft 15 /106
2.4Electro-Photographic Processor
The electro-photographic processor prints out the image data to be sent from the main control
board on sheets of paper. Figure 2-3 shows the layout drawing of the electro-photographic
processor.
(1) Image drum unit
The image drum unit makes a toner adhere to the formed electrostatic latent image with static
electricity. This electrostatic latent image is formed by the lights irradiated from LED heads.
(2) Electromagnetic clutch
The electromagnetic clutch controls the rotation of the hopping roller according to signals
from the control block.
41260201TH Draft 16 /106
Exit roller
Heat roller
(ø 19.910)
6.85
10
OFF
ON
26.50
Outlet sensor
Cleaning roller
(ø 9.000)
Charge roller
(ø 9.000)
6.77
LED head
Drum roller
(ø 16.000)
Developing roller
(ø 14.000)
17.23
12.72
23.18
20.32
64.60
Single tray
Transfer roller
(ø 15.000)
Hopping roller
OFF
32.00
10
Tray printing
10
ON
OFF
Manual feed sensor
Manual printing
Feed roller
Paper sensor
Figure 2-3 Layout Drawing of Electro-Photographic Processor
41260201TH Draft 17 /106
(3) Pulse motor (Main)
This pulse motor of 48 steps/rotation is two-phase excited by the signal from the main control
board; it performs feeding control by switching normal rotation to reverse rotation or vice versa
and turning on/off the electromagnetic clutch. The relationship between the main motor,
electromagnetic clutch, resist gear, drum gear, hopping roller is shown in the table below and
on the subsequent pages.
Main MotorElectromagnetic Clutch
Normal rotation
Reverse rotation
OFF
ON
OFF
Hopping Roller
Non-rotation
Rotation
Non-rotation
Regist GearDrum GearOperation
Non-rotation
Rotation
Rotation
Rotation
Rotation
Rotation
(4) LED head
The shift and latch registers receive image data from the main control board for each dot line.
4,992 LEDs are driven to radiate the image drum.
(5) Heat Assy
The heat Assy consists of a heater, a heat roller, a thermistor, and a thermostat.
The power supply unit supplies AC voltage to the heater according to the HEATON signal
from the main control board to heat the heat roller. The main control board monitors the heat
roller temperature via the thermistor and keeps the temperature constant by turning on/off the
heater AC voltage supply.
If the heat roller temperature rises abnormally, the thermostat of the heater voltage supply
circuit functions to forcibly suspend the AC voltage supply.
Warm-up
Hopping
Prinitng
41260201TH Draft 18 /106
Exit roller
Heat roller
Transfer roller
Cleaning roller
CH roller
Drum roller
Developing roller
Outlet
sensor
Paper sensor
Hopping roller
TRAY printing
Feed roller
Manual
feed
sensor
Manual printing
2 Roller to be driven by reverse
rotation of pulse motor (Main)
1 Motor to be driven by normal
rotation of pulse motor (main)
Roller control by pulse motor (main)
1 Normal rotation of pulse motor (main):Drum roller, transfer roller, cleaning roller, CH roller, developing roller, heat roller, exit roller rotation
2 Reverse rotation of pulse motor (main): Drum roller, transfer roller, cleaning roller, CH roller, developing roller, heat roller, exit roller, feed roller,
hopping roller rotation
Hopping operation from the tray, however, is performed when the electromagnetic clutch is turned on.
Figure 2-4 Schematic Drawing of OKIPAGE8iM Paper Feeding
41260201TH Draft 19 /106
2.5Electro-Photographic Process
(1) Electro-photographic process
The electro-photographic process is outlined below.
1 Charging
The surface of the OPC drum is charged negatively and uniformly by applying the DC
voltage to the CH roller.
2 Exposure
Light emitted from the LED head irradiates the negatively charged surface of the OPC
drum. The surface potential of the irradiated surface attenuates to form the electrostatic
latent image corresponding to the image signal.
3 Development and residual toner recovery
The negatively charged toner is brought into contact with the OPC drum, adhering to the
electrostatic latent image on the OPC drum by static electricity. This adhesion causes
the electrostatic latent image to change to a visible image.
At the same time, the residual toner on the OPC drum is attracted to the developing
rollerby 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 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 Cleaning
The cleaning roller temporarily attracts the residual toner on the transferred OPC drum
with static electricity, then returns the toner to the OPC drum.
6 Fusing
The transferred unfused toner image is fused to a sheet of paper by applying heat and
pressure to the image.
Figure 2-5 is a flow for the electro-photographic process.
41260201TH Draft 20 /106
41260201TH Draft 21 /106
Control signal
LED head
Power
supply
Paper delivery
Paper eject
roller
Outlet sensor
Paper ejectionFusingCleaningTransferDevelopmentPaper feedPaper hopping
Paper feeding
Heat roller
Fusing
Back-up
roller
Charge
roller
Power
supply
Cleaning
roller
Exposure
Charging
CleaningDevelopment
Transfer
Power
supply
Transfer roller
Paper sensor
Developing
Feed roller
Power
supply
roller
Paper
supply
Hopping
roller
: OPC drum rotation direction
Toner
cartridge
Paper
holder
Manual feed
section
Manual feed
sensor
Figure 2-5 Flow for Electro-Photographic Process
: Paper feeding path
2.5.1Explanation of Each Process Operation
(1) Hopping
As shown in the figure below, the clutch for hopping is turned on/off according to current ON/
OFF to a coil.
When the clutch is OFF
Coil
Hopping gear
Spring for resetting
Clutch plate
Magnetic
substance plate
Hopping roller
When the clutch is ON
Hopping shaft
Hopping gear
Pin
Engagement section
Clutch plate
When the clutch is on, the hopping gear engages with the clutch plate to rotate the hopping
roller.
When the clutch is off, the hopping gear is separated from the clutch plate by the spring for
resetting, disabling the rotation of the hopping roller.
41260201TH Draft 22 /106
(2) Printing and warm-up
At warm-up
Regist gear
Hopping gear
Triple gear
Transfer gear
Idle gear
Planetary gear
a"
a'
a
Gear A
Pulse motor (main)
Rotate the pulse motor (main) in the a direction. The planetary gear rotates in the a’ direction,
dislocating its position in the a” direction. This causes the planetary gear to be separated from
gear A. The hopping gear will not rotate. The triple gear and transfer gear rotate via the idle
gear to drive the EP unit.
At printing
Triple gear
Transfer gear
Regist gear
Idle gear
Planetary gear
b"
b'
b
Hopping gear
Gear A
Pulse motor (main)
The paper is further advanced in synchronization to the print data.
41260201TH Draft 23 /106
(3) Charging
Charging is performed by applying DC voltage to the charge roller that is in contact with the
surface of the OPC drum.
High-
voltage
power
supply
Charge roller
OPC drum
(4) Exposure
High-
voltage
power
supply
Light emitted from the LED head irradiates the negatively charged surface of the OPC drum.
The surface potential of the irradiated surface attenuates to form the electrostatic latent image
corresponding to the image signal.
LED head
Charge roller
LED head
OPC drum
41260201TH Draft 24 /106
Paper
Image drum
(5) Development
The electrostatic latent image on the surface of the OPC drum is changed to a visible toner
image by applying a toner to it. Development is performed in the contact part between the
OPC drum and developing roller.
1 The sponge roller negatively charges a toner and applies it to the developing roller.
Developing blade
Charge roller
Developing roller
OPC drum
Sponge roller
2 The toner applied to the developing roller is thin-coated by the developing blade.
3 A toner adheres to the exposure part of the OPC drum in the contact part between the
OPC drum and developing roller. This causes the electrostatic latent image to be
changed to a visible image.
(6) Transfer
The transfer roller is composed of conductive sponge material. This roller is set so that the
surface of the OPC drum and sheets of paper will adhere closely.
A sheet of paper is placed on the surface of the OPC drum and the positive charge opposite
to the negative charge of a toner is applied from the reverse side by the transfer roller.
When a high negative voltage is applied from the power supply to the transfer roller, the
positive charge induced on the surface of the transfer roller moves to the paper side at the
contact part between the transfer roller and the sheet of paper. The positive charge on the
lower side of the sheet of paper then causes the negatively charged toner adhering to the
surface of the OPC drum to move to the upper side of the sheet. This enables transfer to the
sheet of paper.
OPC drum
Paper
Transfer roller
41260201TH Draft 25 /106
High-voltage
power supply
g
(7) Fusing
The transferred unfused toner image is fused to a sheet of paper because heat and pressure
are applied when it passes between the heat roller and back-up roller.
The Teflon-coated heat roller contains a 400 W heater (Halogen lamp) that heats the heat
roller. The thermistor on the surface of the heat roller keeps the temperature of the heat roller
constant. A thermostat is also installed for safety. If temperature rises abnormally, this
thermostat opens to suspend voltage supply to the heater.
The back-up roller is pressurized to the heat roller by the pressure spring on each side.
Thermistor
Separation claw
Heater roller
Heater
Back-up roller
Pressure Sprin
(8) Cleaning
After transfer has terminated, the cleaning roller temporarily draws in the untransferred
residual toner adhering to the OPC drum with static electricity and then returns it to the OPC
drum.
OPC drum
Cleaning roller
High-voltage
power supply
Transfer roller
41260201TH Draft 26 /106
2.6Paper Jam Detection
The OKIPAGE 8iM monitors the paper status when the power supply is on and during printing.
In the following cases, the OKIPAGE 8iM interrupts the printing process as a paper jam. Printing
can be recovered by opening the cover, removing the jammed paper, and closing the cover.
Error
Cause of Error
Paper inlet jam••Only the manual feed sensor detects "Paper exists" when the power supply is on.
The leading part of the paper does not reach the paper sensor although hopping
operation was performed three time.
Paper feed jam• The leading part of the paper does not reach the outlet sensor within a fixed time after it
has passed the paper sensor.
Paper outlet jam• The trailing part of the paper does not pass the outlet sensor within L mm after the
leading part of the paper has passed the outlet sensor.
2.52" (64 mm) L 15.77" (400.6 mm)
<=<
=
Paper size error• The trailing part of the paper does not pass the paper sensor within L mm after the
leading part of the paper has passed the paper sensor.
2.52" (64 mm) L 15.77" (400.6 mm)
<=<
=
Paper Feed Check List
Type of Error
Supervisory Sensor
Reference Value
Error
PluseMinus
Paper feed error
Paper feed jam1
Paper size error
Paper outlet jam
Paper feed jam 2
Electromagnetic clutch ON/
Paper sensor ON
Paper sensor ON/
Outlet sensor ON
Paper sensor ON/
Paper sensor OFF
Outlet sensor ON/
Outlet sensor OFF
Paper end sensor OFF/
Outlet sensor OFF
69.8
122.9
2.52" (64 mm) L
<=<
=
15.77" (400.56 mm)
2.52" (64 mm) L
<=<
=
15.77" (400.56 mm)
121.9
35
20.0
—
45.0
20.0
—
—
—
45.0
20.0
Unit: mm
41260201TH Draft 27 /106
Pulse motor
(main)
Normal
rotation
OFF
Reverse
rotation
Electromagnetic
clutch
Manual feed
sensor
Paper sensor
Outlet sensor
Operation mode
OFF
ON
OFF
ON
OFF
ON
OFF
ON
Warm-upPaper feedPrinting
Timing Chart for Paper Feed (Tray Feed)
41260201TH Draft 28 /106
2.7Toner Low Detection
• Hardware configuration of toner sensor
The figure below shows the hardware configuration of the toner sensor.
Image drum unit
Agitation bar (iron)
Magnet
Toner sensor lever
Hardware Configuration of Toner Sensor
41260201TH Draft 29 /106
• Toner detection method
(1) Toner sensor monitoring conditions are shown in the figure below.
Toner sensor
Magnet draw-in
t1
T
Caution:
The toner sensor is not monitored when the drum is inactive.
(a) When the toner-low state continues twice, Toner Low occurs. (This state is monitored
at a cycle of 40 milliseconds.)
(b) When the toner-full state continues twice, Toner Low is released. (This state is
monitored at a cycle of 40 milliseconds.)
(c) When the toner sensor does not change over two cycles (T x 2), the toner sensor alarm
state occurs.
(d) After the EP unit has been replaced (after the drum counter has been reset), Toner
Low is not detected when the drum counter indicates 1 to 100 counts.
(2) The basic rotation cycle of the toner sensor is as follows:
T time
Basic rotation cycle of toner sensor
Toner low time
Toner full time
2.5 sec.
t1 > 0.64 sec.
0.64 sec. > t1 > 0.28 sec.
41260201TH Draft 30 /106
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