Fresa G024 User manual

FRESA (G024)
SERVICE MANUAL
[Engine]

øIMPORTANT SAFETY NOTICES
PHYSICAL INJURY PREVENTION
1. Before disassembling or assembling parts of the printer and peripherals,
make sure that the power cord is unplugged.
2. The wall outlet should be near the printer and easily accessible.
3. Note that some printer components are supplied with electrical voltage even
if the main switch is turned off.
4. If an adjustment or operation check must be made requiring the removal or
opening of the exterior covers while the main switch is on, keep hands away
from electrified or mechanically driven components.
5. The printer drives some of its components when it completes the warm-up
period. Keep hands away from mechanical and electrical components when
the printer starts operation.
6. The interior and metal parts for the fusing unit become extremely hot while
the printer is operating. Do NOT touch these components with bare hands.
HEALTH SAFETY CONDITIONS
1. Never operate the printer without ozone filters installed.
2. Always replace the ozone filters with the specified replacement at the
specified maintenance intervals.
3. Toner is non-toxic, but if it gets in your eyes by accident, it may cause
temporary eye discomfort. Remove it with eye drops or flush eyes with
water. If this is unsuccessful, get medical attention immediately.
SAFETY AND ECOLOGICAL NOTES FOR DISPOSAL
1. Do NOT incinerate toner cartridges, development toner magazine (DTM) or
used toner. Toner dust may ignite suddenly when exposed to an open
flame.
2. Dispose of used toner bottle and photoconductor unit (PCU) in accordance
with local regulations. (These are non-toxic supplies.)
3. Dispose of replaced parts in accordance with local regulations.

LASER SAFETY
The Center for Devices and Radiological Health (CDRH) prohibits the repair of
laser-based optical units in the field. The optical unit can only be repaired in a
factory or at a location with the requisite equipment. The laser subsystem is only
replaceable in the field by a qualified Customer Engineer. The laser chassis is not
field repairable. Customer engineers are therefore directed to return all chassis and
laser subsystems to the factory or service depot when the optical subsystem
requires replacement.
øWARNING
Use of controls, or adjustment, or performance of procedures other than
those specified in this manual may result in hazardous radiation exposure.
øWARNING
WARNING: Turn OFF the main switch before attempting any of the
procedures in the Optical Unit section. Laser beams can
seriously damage your eyes.
CAUTION MARKING:

Trademarks
Microsoft, Windows 98/95/3.1x, and Windows NT 4.0 are registered trademarks of
Microsoft Corporation.
Macintosh and AppleTalk are registered trademarks of Apple Computer, Inc.
NetWare is a registered trademark of Novell, Inc.
Ethernet is a registered trademark of Xerox Corporation.
General Notice:
Other product names used herein are for identification purposes only and may be
trademarks of their respective companies. We disclaim any and all rights in those
marks.

31 March, 1999 SPECIFICATIONS
1-1
Overall
Information
1. OVERALL MACHINE INFORMATION
1.1 SPECIFICATIONS
Configuration Desk top
Print Process Dry electrostatic transfer system
Resolution 600 dpi
Paper Size Standard tray
Short edge feed:
A3, 11" x 17", 81/2" x 14", Others* (B4 JIS, 8" x 13",
81/4" x 13", 81/2" x 13")
Long edge feed:
A4, 81/2" x 11", 71/4" x 101/2", Others* (B5 JIS, A5,
51/2" x 81/2")
By-pass feed tray*
Short edge feed:
A3, A6, B4 JIS, B6 JIS, 11" x 17", 81/2" x 14", 8" x 13",
81/4" x 13", 81/2" x 13"
Long edge feed:
A4, A5, B5 JIS, 81/2" x 11", 51/2" x 81/2", 71/4" x 101/2"
Custom size paper (Length: 148 to 432 mm, Width: 90
to 297 mm)
* Specify the paper size with the system menu (at the
operation panel by the user).
Paper Weight Standard and optional trays: 64 to 105 g/m2(17 to 28 lbs.)
By-pass feed tray: 64 to 157 g/m2(17 to 42 lbs.)
Plain paper mode: 64 to 105 g/m2
Thick paper mode: 105 to 157 g/m2, adhesive labels
OHP transparency mode: OHP transparencies
First Printout Time Color: Less than 30 seconds (A4)
Monochrome: Less than 14 seconds (A4)
Print Speed Color: 5 ppm (A4/81/2" x 11")
Monochrome: 17 ppm (A4/81/2" x 11")
Warm-up Time Less than 450 seconds (at 23°C/73°F)
Paper Capacity Standard tray: 250 sheets (80 g/m2, 20 lbs.)
By-pass feed tray: 50 sheets (80 g/m2, 20 lbs.)
Optional trays: 500 sheets (80 g/m2, 20 lbs.)
Paper Output
Capacity 250 sheets (A4/81/2" x 11" or less) 100 sheets (More than A4/81/2" x 11")
Output Method Face down

SPECIFICATIONS 31 March, 1999
1-2
Power Supply 120 V, 60 Hz, 10 A
220 to 240 V, 50/60 Hz, 5.2 A
Power Consumption Maximum: Less than 1200 W
Average during printing: Less than 750 W
Standby mode: Less than 150 W
Energy saver mode: Less than 45 W
Noise Emission
(Sound Power Level) Stand-by: Less than 43 dB Operating: Less than 64 dB (without paper tray unit)
Less than 66 dB (with paper tray unit)
Dimensions 660 x 625 x 475 mm (26" x 24.6" x 18.7")
(without paper tray unit)
Weight Approximately 62 kg (136.7 lbs.)
(including controller)
Options Paper Feed Unit Type 305 (Paper Tray Unit) – up to two of
these units can be installed

31 March, 1999 MECHANICAL OVERVIEW
1-3
Overall
Information
1.2 MECHANICAL OVERVIEW
1.2.1 IMAGE FORMATION PROCESS OVERVIEW
1. OPC belt
2. Charge
3. Exposure
4. Development
5. Transfer belt
6. Transfer belt cleaning
7. Paper separation
8. Paper transfer (secondary transfer)
9. Belt transfer (primary transfer)
10. ID sensor
11. OPC belt cleaning
12. Quenching
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MECHANICAL OVERVIEW 31 March, 1999
1-4
(1) OPC belt
The OPC (organic photoconductor) belt is the central part of the machine. This is
where the laser beam writes an image of the original.
(2) Charge
A negative corona discharge in darkness negatively charges the OPC belt. The
grid ensures the even distribution of charge over the OPC belt.
(3) Exposure
The laser beam from the laser diode (LD) goes through the lens and the mirror and
reaches the OPC belt. The beam discharges the areas of the OPC belt that it
illuminates. Turning the laser beam on and off, and varying the intensity of the
beam, creates a latent image on the OPC belt.
(4) Development
The development section consists of four independent development units, one for
each color (Y, C, M, and K) and the structure necessary to support them. These
modules are known as DTMs (Development Toner Magazines).
This unit forms visual images by allowing toner to adhere to portions of the OPC
belt where negative potentials are lower than the development bias. In this
machine, monocomponent toner is used (there is no carrier).
In black single-color mode (1C), the image is developed in K only. In full color
mode (4C), the image is developed in Y, C, M, and K, in that order.
(5) Transfer
This printer uses a transfer belt. Four toner images, each a different color, are
super-imposed onto each other on the transfer belt. The combined image is then
transferred to the paper.
(6) Transfer belt cleaning
A cleaning brush applies lubricant to the transfer belt to improve cleaning. Then, a
blade scrapes off the remaining toner on the transfer belt.
(7) Paper separation
Paper separates from the transfer belt when the belt curves away from it. The roller
at the end of the transfer belt is 31 mm in diameter.
(8) Paper transfer (secondary transfer)
A charge applied to the transfer roller attracts the toner from the transfer belt onto
the paper.
(9) Belt transfer (primary transfer)
A charge applied to the bias roller attracts toner from the OPC belt onto the transfer
belt.
(10) ID sensor
The ID sensor detects the density of the ID sensor pattern on the transfer belt. The
ID sensor outputs determine the process control conditions.

31 March, 1999 MECHANICAL OVERVIEW
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Information
(11) OPC belt cleaning
A cleaning brush applies lubricant to the OPC belt to improve cleaning. Then, a
blade scrapes off the remaining toner on the OPC belt.
(12) Quenching
After cleaning, the entire surface of the OPC belt is exposed to light from a red
LED. This quenches the residual potential on the OPC belt, in preparation for the
next image.

MECHANICAL OVERVIEW 31 March, 1999
1-6
1.2.2 TRANSFER
An image is formed on the OPC belt in four colors, one color at a time. The
resulting four images transfer to the transfer belt in the order of Y, C, M, then K.
These four images form a full-color image on the transfer belt, then the image is
finally transferred to the paper.
G024V670.WMF
Forming a visual
image on the OPC
belt
Transferring the
image onto the
transfer belt
Turning the transfer
belt
Putting Y on
the belt
Putting C on Y
Putting M on Y
and C
Putting K on
Y, C, and M
Transferring the image
on the transfer belt onto
the paper (the paper
transfer side is the
opposite side from the
OPC belt)

31 March, 1999 MECHANICAL OVERVIEW
1-7
Overall
Information
1.2.3 CHARGE CORONA UNIT VOLTAGES
The charge corona wire receives a constant current (C) of – 700 µA (about – 5000
V).
The charge grid voltage (G) varies depending on the process control results.
Range: –320 V to –820 V
Default: –600 V
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OPC belt
Cleaning blade
Charge grid
Quenching
lamp
Charge corona unit
G = –600 V
C = –700 µA
(About –5000 V)

MECHANICAL OVERVIEW 31 March, 1999
1-8
1.2.4 DEVELOPMENT UNIT BIAS VOLTAGES
Each development unit contains a supply roller and a development roller. These
rollers are conductive. The voltage applied to the supply roller (SB) depends on the
process control results. The other voltages in turn all depend on SB, as described
below.
SB (supply roller bias)
Default: -348 V
Range: -218 V to –468 V
BL (development blade bias)
This is always SB – 132 V. If SB changes, so does BL.
Default: -480 V
180 Vac is always super-imposed over this voltage.
B (development roller voltage)
This is always SB +68 V. If SB changes, so does B.
The development roller voltage (B) is the VBdetermined during process control.
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Supply roller
Development
roller OPC belt
Development blade
Toner
180 VAC equivalent
BL = –480 V
SB = –348 V
68 V
BL = –480 V
AC180 V
(400 Vp-p)
2 kHz

31 March, 1999 MECHANICAL OVERVIEW
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Information
1.2.5 TRANSFER BIAS VOLTAGES
Primary transfer (from OPC belt to transfer belt)
An 800-V bias voltage (TB) is applied to the bias roller. This attracts the toner from
the OPC belt.
Secondary transfer (from transfer belt to paper)
A constant +16 µA current (TC) is supplied to the paper transfer roller (at about 1.8
kV) to attract the toner from the transfer belt.
The machine adjusts the transfer current automatically for variations in
temperature, humidity, paper size, and paper thickness.
After a paper jam has occurred, the paper transfer roller must be cleaned. Positive
and negative currents are supplied alternately to repel any particles that got stuck
on the roller as a result of the paper jam.
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Paper
Paper transfer roller
TC– = –16 µA
(About –1.1 kV)
Transfer belt
Toner
OPC belt
Bias roller
TC+ = +16 µA
(About +1.8 kV)
TB = 800 V

MAIN UNIT LAYOUT 31 March, 1999
1-10
1.3 MAIN UNIT LAYOUT
1. Optical housing unit
2. Main control unit (MCU)
3. High voltage supply unit
4. Controller board
5. Power supply unit
6. Fusing unit
7. Paper transfer unit
8. Photoconductor unit (PCU)
9. Paper tray/paper feed mechanism
10. Development unit
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31 March, 1999 MAIN UNIT LAYOUT
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Overall
Information
(1) Optical housing unit
•Optical system: 6-sided polygon mirror, F-theta mirror, BTL
•Resolution: 600 dpi
•Modulation method: PM+PWM
(2) MCU
•CPU: XC68334 GFC16
•Engine system control
•Process control
•Video interface
(3) High voltage supply unit
•Constant current: Paper transfer, charge corona wire
•Constant voltage: Charge corona grid, belt transfer, supply roller,
development blade
(4) Controller board
•Host interface
•Video interface
•Image processing
•Operation panel control
(5) Power supply unit
•Outputs: +5 VDC, +24 VDC, 120/230 VAC
(6) Fusing unit
•Fusing method: Hot roller method
•Oil application: Application roller method
•Cleaning: Cleaning roller method
•Temperature detection: Thermistor
•Safety precaution: Thermofuse
(7) Paper transfer unit
•Transfer: Transfer roller method
(8) PCU
A unit consisting of the OPC belt and the primary (belt) transfer section.
•OPC belt: 93mm diameter
•Charging: Single scorotron charge corona wire
•Primary transfer: Transfer belt
•Cleaning: Counter blade
•Lubricant: Zinc stearate
(9) Tray/transport
•Standard tray: Universal tray, friction pad separation
By-pass tray: FRR method
(10) Development unit
•Development method: Monocomponent non-magnetic toner
•Development unit changeover: Revolver method
•Toner replenishment: DTM change

PARTS LAYOUT 31 March, 1999
1-12
1.4 PARTS LAYOUT
1.4.1 MECHANICAL COMPONENT LAYOUT
1. Tray paper feed roller
2. Paper tray
3. Charge corona unit
4. Polygon mirror
5. MCU (Main control unit)
6. High voltage supply unit
7. Development unit
8. Controller board
9. Power supply unit
10. Exit rollers
11. Hot roller
12. Pressure roller
13. Transfer belt cleaning unit
14. Transport fan
15. Paper transfer unit
16. Transfer belt
17. Registration rollers
18. Registration sensor
19. By-pass feed table
20. By-pass paper feed roller
21. OPC belt
22. Relay rollers
23. OPC belt cleaning unit
24. Used toner tank
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31 March, 1999 PARTS LAYOUT
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1.4.2 DRIVE LAYOUT
1. Main motor
2. Fusing drive input gear
3. Fusing drive gear
4. Transfer belt toner collection drive
gear
5. Transfer roller clutch
6. Registration clutch
7. By-pass feed clutch
8. Relay roller clutch
9. Pull-out clutch
10. Paper feed clutch
11. Paper feed drive gear
12. OPC cleaning drive gear
13. Revolver drive gear
14. Revolver motor
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PARTS LAYOUT 31 March, 1999
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1. PCU pulley
2. PCU motor
3. OPC drive relay gear
4. OPC drive gear
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31 March, 1999 PARTS LAYOUT
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1.4.3 SENSORS
1. Exit sensor
2. Oil end sensor
3. Transfer belt H.P. sensor
4. Transfer roller position sensor
5. Used toner sensor
6. PCU reset sensor
7. Paper end sensor
8. ID sensor
9. Pull-out sensor
10. By-pass paper end sensor
11. Registration sensor
12. Toner end sensor
13. Revolver H.P. sensor
14. Development toner magazine
(DTM) set sensor
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PARTS LAYOUT 31 March, 1999
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1.4.4 SWITCHES
1. Main switch
2. Exit cover switch
3. Door safety switches
4. Paper size switch
5. PCU set switch
6. Charge corona unit set switch
7. Development toner magazine (DTM) cover switch
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