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C231/C237
SERVICE MANUAL
RICOH GROUP COMPANIES
PN: RCSMC231
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®
®
SERVICE MANUAL
C231/C237
RICOH GROUP COMPANIES
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Page 5
C231/C237
SERVICE MANUAL
PN:RCSMC231
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It is the reader's responsibility when discussing the information contained within this
document to maintain a level of confidentiality that is in the best interest of Ricoh
Corporation and its member companies.
NO PART OF THIS DOCUMENT MAY BE REPRODUCED IN ANY
FASHION AND DISTRIBUTED WITHOUT THE PRIOR
PERMISSION OF RICOH CORPORATION.
All product names, domain names or product illustrations, including desktop images,
used in this document are trademarks, registered trademarks or the property of their
respective companies.
They are used throughout this book in an informational or editorial fashion only and for
the benefit of such companies. No such use, or the use of any trade name, or web
site is intended to convey endorsement or other affiliation with Ricoh products.
2000 RICOH Corporation. All rights reserved.
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s
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h
g
o
l
y
WARNING
The Service Manual contains informatio
regarding service techniques, procedures,
processes and spare parts of office equipmen
distributed by Ricoh Corporation. Users of thi
manual should be either service trained o
certified by successfully completing a Rico
Technical Training Program.
Untrained and uncertified users utilizin
information contained in this service manual t
repair or modify Ricoh equipment risk persona
injury, damage to property. or loss of warrant
protection.
Ricoh Corporation
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LEGEND
PRODUCT CODE COMPANY
GESTETNER RICOH SAVIN
C231 5306L JP1030 3150DNP
C237 5308L JP1230 3150eDNP
DOCUMENTATION HISTORY
REV. NO. DATE COMMENTS
* 7/98 Original Printing
1 8/2000 C237 Addition
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Page 13
C231/C237
TABLE OF CONTENTS
OVERALL INFORMATION............................................................... 1-1
1.1 SPECIFICATION....................................................................................... 1-1
1.2 GUIDE TO COMPONENTS AND THEIR FUNCTION............................... 1-5
1.2.1 MACHINE EXTERIOR......................................................................1-5
1.2.2 MACHINE INTERIOR....................................................................... 1-6
1.2.3 OPERATION PANEL........................................................................1-7
Keys......................................................................................................1-7
Indicators ..............................................................................................1-9
1.3 PRINTING PROCESS............................................................................. 1-10
1.4 MECHANICAL COMPONENT LAYOUT ................................................. 1-11
1.5 ELECTRICAL COMPONENT LAYOUT...................................................1-12
1.5.1 ADF ................................................................................................ 1-12
1.5.2 MAIN BODY ................................................................................... 1-13
Boards ................................................................................................ 1-14
Motors................................................................................................. 1-14
Solenoids............................................................................................ 1-15
Switches ............................................................................................. 1-15
Sensors ..............................................................................................1-15
Counters .............................................................................................1-16
Others................................................................................................. 1-16
1.6 DRIVE LAYOUT...................................................................................... 1-17
DETAILED SECTION DESCRIPTIONS............................................ 2-1
2.1 SCANNER AND OPTICS.......................................................................... 2-1
2.1.1 BOOK SCANNER OVERVIEW ........................................................ 2-1
2.1.2 ADF OVERVIEW.............................................................................. 2-2
2.1.3 CONTACT IMAGE SENSOR ........................................................... 2-4
2.1.4 DRIVE MECHANISM........................................................................2-5
Book Scanner .......................................................................................2-5
ADF ......................................................................................................2-6
2.1.5 PICK-UP AND FEED (ADF) ............................................................. 2-7
2.1.6 SEPARATION MECHANISM (ADF)................................................. 2-8
2.1.7 ERROR CONDITIONS..................................................................... 2-9
Book Scanner .......................................................................................2-9
ADF ......................................................................................................2-9
2.2 IMAGE-PROCESSING............................................................................ 2-10
2.2.1 OVERVIEW....................................................................................2-10
2.2.2 A/D CONVERSION PROCESSING................................................2-11
Shading Distortion Correction............................................................. 2-11
Original Background Correction.......................................................... 2-12
Peak Hold ...........................................................................................2-12
SM C231/C237
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2.2.3 BINARY PROCESSING ................................................................. 2-13
Data Compensation Processing ......................................................... 2-13
MTF Correction................................................................................... 2-14
Binary Processing in Letter/Photo Mode............................................. 2-14
Error Diffusion..................................................................................... 2-15
2.2.4 MAIN SCAN MAGNIFICATION ......................................................2-16
2.2.5 IMAGE POSITION ADJUSTMENT IN THE MAIN
SCAN DIRECTION......................................................................... 2-17
2.2.6 PASTE SHADOW ERASE MODE.................................................. 2-17
2.2.7 THERMAL HEAD ...........................................................................2-18
Specifications .....................................................................................2-18
Thermal Head Control ........................................................................ 2-18
Thermal Head Protection.................................................................... 2-18
Remarks for Handling the Thermal Head ...........................................2-19
2.3 MASTER EJECT..................................................................................... 2-20
2.3.1 OVERALL....................................................................................... 2-20
2.3.2 MASTER CLAMPER OPEN MECHANISM .................................... 2-21
Drum Position Lock Mechanism ......................................................... 2-21
2.3.3 MASTER EJECT ROLLER MECHANISM...................................... 2-22
2.3.4 PRESSURE PLATE MECHANISM.................................................2-23
2.4 MASTER FEED....................................................................................... 2-24
2.4.1 OVERALL....................................................................................... 2-24
2.4.2 MASTER FEED MECHANISM .......................................................2-25
2.4.3 MASTER CLAMPER OPERATION AND TENSION ROLLER
RELEASE MECHANISM................................................................ 2-26
2.4.4 CUTTER MECHANISM..................................................................2-27
2.5 DRUM .....................................................................................................2-28
2.5.1 OVERALL....................................................................................... 2-28
2.5.2 DRUM DRIVE MECHANISM.......................................................... 2-29
2.5.3 INK SUPPLY MECHANISM ........................................................... 2-30
2.5.4 INK ROLLER MECHANISM ........................................................... 2-31
2.5.5 INK SUPPLY CONTROL................................................................ 2-32
2.5.6 DETECTION OF MASTERS ON THE DRUM ................................ 2-33
2.6 PAPER FEED..........................................................................................2-34
2.6.1 OVERALL....................................................................................... 2-34
2.6.2 PAPER FEED MECHANISM.......................................................... 2-35
2.6.3 PAPER FEED/SEPARATION PRESSURE ADJUSTMENT
MECHANISM ................................................................................. 2-36
2.6.4 REGISTRATION ROLLER MECHANISM ......................................2-37
Registration Roller Drive..................................................................... 2-37
Registration Roller Up/Down Mechanism ........................................... 2-38
2.6.5 PRINTING PRESSURE MECHANISM........................................... 2-39
2.6.6 PAPER TABLE MECHANISM........................................................ 2-40
Table Up and Down Mechanism.........................................................2-40
Paper End Detection Mechanism .......................................................2-40
Paper Table Side Fence Mechanism.................................................. 2-41
Paper Table Side-to-Side Shift Mechanism........................................ 2-41
Side Fence Friction Pads....................................................................2-42
C231/C237 SM
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2.7 PAPER DELIVERY ................................................................................. 2-43
2.7.1 OVERALL....................................................................................... 2-43
2.7.2 PAPER DELIVERY UNIT DRIVE MECHANISM ............................ 2-44
2.7.3 PAPER SEPARATION FROM DRUM............................................ 2-45
2.7.4 EXIT PAWL DRIVE MECHANISM .................................................2-46
2.8 ERROR DETECTION.............................................................................. 2-47
2.8.1 ORIGINAL JAM DETECTION ........................................................2-47
2.8.2 MASTER EJECT JAM DETECTION .............................................. 2-47
2.8.3 MASTER FEED JAM DETECTION ................................................2-48
2.8.4 PAPER FEED JAM DETECTION...................................................2-49
INSTALLATION................................................................................ 3-1
3.1 INSTALLATION REQUIREMENTS........................................................... 3-1
3.1.1 OPTIMUM ENVIRONMENTAL CONDITION.................................... 3-1
3.1.2 ENVIRONMENTS TO AVOID ..........................................................3-1
3.1.3 POWER CONNECTION................................................................... 3-1
3.1.4 ACCESS TO MACHINE ................................................................... 3-2
3.2 INSTALLATION PROCEDURE................................................................. 3-3
3.2.1 MAIN BODY ..................................................................................... 3-3
Accessory Check.................................................................................. 3-3
Installation Procedure........................................................................... 3-4
3.2.2 AUTO DOCUMENT FEEDER (OPTION) ......................................... 3-9
Accessory Check.................................................................................. 3-9
Installation Procedure......................................................................... 3-10
3.2.3 TAPE MARKER (OPTION).............................................................3-14
Accessory Check................................................................................ 3-14
Installation Procedure - For C231 -.....................................................3-15
3.2.4 COLOR DRUM (OPTION).............................................................. 3-17
3.2.5 INTERFACE BOARD (OPTION) .................................................... 3-18
Accessory Check................................................................................ 3-18
Installation Procedure......................................................................... 3-18
SERVICE TABLES ........................................................................... 4-1
4.1 SERVICE REMARKS................................................................................ 4-1
4.1.1 MASTER FEED SECTION............................................................... 4-1
1. Thermal Head Installation................................................................. 4-1
2. Thermal Head Voltage Adjustment................................................... 4-1
4.1.2 PAPER FEED SECTION.................................................................. 4-1
1. Friction Pad ......................................................................................4-1
2. Paper Feed Roller and Paper Separation Roller ..............................4-1
3. Paper Guide Plate Position for Registration Roller ........................... 4-1
4.1.3 DRUM AND DRUM DRIVE SECTION..............................................4-2
1. Main Motor........................................................................................ 4-2
2. Doctor Roller..................................................................................... 4-2
3. Drum Master Clamper ...................................................................... 4-2
SM C231/C237
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Rev. 11/2000
4.1.2 PAPER FEED SECTION..................................................................4-1
1. Friction Pad.......................................................................................4-1
2. Paper Feed Roller and Paper Separation Roller 1............................4-1
3. Paper Feed Roller and Paper Separation Roller 2............................4-1
4. Paper Guide Plate Position for Registration Roller ...........................4-1
4.1.3 DRUM AND DRUM DRIVE SECTION..............................................4-2
1. Main Motor........................................................................................4-2
2. Doctor Roller.....................................................................................4-2
3. Drum Master Clamper.......................................................................4-2
4. Ink Roller Unit ...................................................................................4-2
5. Ink Pump 1........................................................................................4-2
6. Ink Pump 2........................................................................................4-2
4.1.4 PAPER DELIVERY SECTION..........................................................4-3
1. Exit Pawl ...........................................................................................4-3
4.1.5 ELECTRICAL COMPONENTS.........................................................4-3
1. Main Processing Unit (MPU) 1..........................................................4-3
2. Main Processing Unit (MPU) 2..........................................................4-3
3. Power Supply Unit ............................................................................4-3
4. Sensor Adjustments..........................................................................4-3
4.2 DIP SW, LED, VR, TP, AND FUSE TABLES ............................................4-4
4.2.1 TEST POINTS ..................................................................................4-4
MPU......................................................................................................4-4
4.2.2 POTENTIOMETERS ........................................................................4-4
MPU......................................................................................................4-4
Power Supply Unit ................................................................................4-4
4.2.3 LED'S ...............................................................................................4-4
4.2.4 FUSES..............................................................................................4-5
MPU......................................................................................................4-5
PSU ......................................................................................................4-5
4.3 SERVICE CALL CODES ...........................................................................4-6
4.4 SERVICE PROGRAM MODE....................................................................4-8
4.4.1 ACCESS PROCEDURE...................................................................4-8
Service Program Mode Access Procedure (For Engineers) .................4-8
Service Program Mode Access Procedure (For Users) ........................4-9
Change Adjustment Values or Modes ................................................4-10
4.4.2 SERVICE PROGRAM TABLE........................................................4-11
Remarks .............................................................................................4-20
4.4.3 INPUT/OUTPUT CHECK MODE....................................................4-23
Input/Output Check Mode Access Procedure .....................................4-23
Input Check Table...............................................................................4-24
Output Check Table............................................................................4-26
4.5 TEST PATTERN IMAGE MODE .............................................................4-28
4.6 USER CODE MODE ...............................................................................4-29
4.7 ROM HISTORY .......................................................................................4-31
4.7.1 C231 FIRMWARE MODIFICATION HISTORY................................4-31
5. PREVENTIVE MAINTENANCE................................................... 5-1
5.1 MAINTENANCE TABLE ............................................................................5-1
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6.2 COPY IMAGE ADJUSTMENT...................................................................6-6
6.2.1 LEADING EDGE REGISTRATION ADJUSTMENT.......................... 6-6
6.2.2 SIDE-TO-SIDE REGISTRAION ADJUSTMENT............................... 6-7
6.2.3 VERTICAL MAGNIFICATION ADJUSTMENT .................................6-8
6.2.4 LEADING EDGE BLANK MARGIN ADJUSTMENT .........................6-9
6.3 MPU REPLACEMENT ............................................................................6-10
6.4 ORIGINAL FEED SECTION.................................................................... 6-11
6.4.1 ADF ROLLER ASSSEMBLY .......................................................... 6-11
6.4.2 PICK-UP ROLLER .........................................................................6-11
6.4.3 FEED ROLLER ..............................................................................6-12
6.4.4 SEPARATION ROLLER................................................................. 6-12
6.4.5 ADF MOTOR AND COVERS ......................................................... 6-13
6.4.6 R0 AND R1 ROLLERS................................................................... 6-13
6.4.7 R2 ROLLER ...................................................................................6-14
6.4.8 DOCUMENT SENSOR...................................................................6-15
6.4.9 SCAN LINE SENSOR ....................................................................6-15
6.4.10 COVER SENSORS ...................................................................... 6-16
6.5 MASTER FEED SECTION...................................................................... 6-17
6.5.1 MASTER MAKING UNIT REMOVAL..............................................6-17
6.5.2 THERMAL HEAD REMOVAL......................................................... 6-19
Remarks for thermal head installation ................................................ 6-20
6.5.3 THERMAL HEAD VOLTAGE ADJUSTMENT ................................ 6-21
6.5.4 MASTER END SENSOR ADJUSTMENT....................................... 6-23
6.6 MASTER EJECT SECTION ....................................................................6-24
6.6.1 MASTER EJECT UNIT REMOVAL ................................................ 6-24
6.7 PAPER FEED SECTION......................................................................... 6-25
6.7.1 PAPER FEED ROLLER, PICK-UP ROLLER,
AND FRICTION PAD ....................................................................6-25
6.7.2 PAPER SEPARATION PRESSURE ADJUSTMENT...................... 6-26
6.7.3 PAPER FEED PRESSURE ADJUSTMENT................................... 6-27
6.7.4 REGISTRATION ROLLER CLEARANCE ADJUSTMENT .............6-28
6.8 PRINTING SECTION .............................................................................. 6-29
6.8.1 PRESS ROLLER REMOVAL ......................................................... 6-29
6.8.2 PRESS ROLLER LOCK LEVER ADJUSTMENT ...........................6-30
6.8.3 PRINTING PRESSURE ADJUSTMENT.........................................6-32
6.9 DRUM AND DRIVE SECTION ................................................................ 6-33
6.9.1 DRUM CLOTH SCREEN REMOVAL ............................................. 6-33
Remarks for the cloth screen installation............................................ 6-34
6.9.2 DRUM MASTER CLAMPER AND METAL SCREEN REMOVAL... 6-36
Remarks for drum screen installation ................................................. 6-38
6.9.3 INK ROLLER UNIT REMOVAL ...................................................... 6-39
6.9.4 DOCTOR ROLLER GAP ADJUSTMENT....................................... 6-41
6.9.5 INK DETECTION ADJUSTMENT................................................... 6-43
6.9.6 INK PUMP REMOVAL AND PLUNGER
POSITION ADJUSTMENT .............................................................6-44
6.9.7 MAIN DRIVE TIMING BELT TENSION ADJUSTMENT .................6-46
6.9.8 MAIN MOTOR PULLEY POSITION ADJUSTMENT ......................6-48
SM C231/C237
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Page 18
6.10 PAPER DELIVERY SECTION...............................................................6-49
6.10.1 VACUUM UNIT REMOVAL ..........................................................6-49
6.10.2 DELIVERY BELT/PAPER EXIT SENSOR REMOVAL ................. 6-50
6.10.3 VACUUM MOTOR REMOVAL .....................................................6-51
6.10.4 EXIT PAWL CLEARANCE ADJUSTMENT ..................................6-52
6.10.5 EXIT PAWL DRIVE TIMING ADJUSTMENT................................ 6-53
TAPE MARKER C532
SPECIFICATIONS ............................................................................ 7-1
BASIC OPERATION......................................................................... 7-2
2.1 OVERVIEW............................................................................................... 7-2
2.2 DRIVE AND CUTTING MECHANISM .......................................................7-3
2.3 MANUAL CUT........................................................................................... 7-4
REPLACEMENT AND ADJUSTMENT ............................................. 7-5
3.1 CUTTER REPLACEMENT........................................................................ 7-5
3.2 CUTTER HOME POSITION SENSOR REPLACEMENT.......................... 7-6
3.3 TAPE CUT LENGTH ADJUSTMENT........................................................ 7-7
PRIPORT CONTROLLER USER’S GUIDE ...................................... 8-1
POINT TO POINT DIAGRAM
C231/C237 SM
vi
Page 19
Rev. 08/2000
C237
1. OVERALL INFORMATION.......................................................... 1-1
1.1 ESSENTIAL DIFFERENCES BETWEEN THE C237 AND C231
MODELS ................................................................................................... 1-1
1.2 SPECIFICATIONS .................................................................................... 1-4
1.3 NEW ELECTRICAL COMPONENTS ........................................................ 1-5
1.3.1 MAIN BODY ..................................................................................... 1-5
1.3.2 TABLES OF ELECTRICAL COMPONENTS.................................... 1-5
Boards .................................................................................................. 1-5
Switches ............................................................................................... 1-5
2. DETAILED SECTION DESCRIPTIONS....................................... 2-1
2.1 PAPER FEED............................................................................................2-1
2.1.1 PAPER FEED/SEPARATION PRESSURE ADJUSTMENT
MECHANISM ................................................................................... 2-1
2.2 PAPER DELIVERY ...................................................................................2-2
2.2.1 EXIT PAWL AIR PUMP MECHANISM (CHINESE MODEL ONLY) . 2-2
3. INSTALLATION........................................................................... 3-1
4. SERVICE TABLES ...................................................................... 4-1
4.1 SERVICE CALL CODES........................................................................... 4-1
4.2 SERVICE PROGRAM TABLE................................................................... 4-3
4.3 INPUT/OUTPUT CHECK MODE............................................................. 4-12
Input Check Table ..............................................................................4-12
Output Check Table............................................................................ 4-14
5. PREVENTIVE MAINTENANCE ................................................... 5-1
6. REPLACEMENT AND ADJUSTMENT ........................................ 6-1
6.1 MASTER FEED SECTION........................................................................ 6-1
6.1.1 MASTER END SENSOR ADJUSTMENT......................................... 6-1
6.2 MASTER EJECT SECTION ......................................................................6-2
6.2.1 MASTER EJECT UNIT REMOVAL .................................................. 6-2
6.3 PAPER FEED SECTION........................................................................... 6-2
6.3.1 PAPER SEPARATION PRESSURE ADJUSTMENT........................ 6-2
6.4 PAPER DELIVERY SECTION................................................................... 6-3
6.4.1 AIR PUMP ADJUSTMENT (CHINESE MODEL ONLY) ...................6-3
C237 POINT TO POINT DIAGRAM
SM C231/C237
vii
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Page 21
IMPORTANT SAFETY NOTICES
PREVENTION OF PHYSICAL INJURY
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. If any adjustment or operation check has to be made with exterior covers off or
open while the main switch is turned on, keep hands away from electrified or
mechanically driven components.
HEALTH SAFETY CONDITIONS
1. If you get ink in your eyes by accident, try to remove it with eye drops or flush
with water as first aid. If unsuccessful, get medical attention.
2. If you ingest ink by accident, induce vomiting by sticking a finger down your
throat or by giving soapy or strong salty water to drink.
OBSERVANCE OF ELECTRICAL SAFETY STANDARDS
1. The printer and its peripherals must be installed and maintained by a customer
service representative who has completed the training course on those models.
CAUTION
The RAM has a lithium battery which can explode if handled incorrectly.
Replace only with the same type of RAM. Do not recharge or burn this
battery. Used RAM's must be handled in accordance with local regulations.
ATTENTION
La carte RAM comporte une pile au lithium qui présente un risque
d'explosion en cas de mauvaise manipulation. Remplacer la pile
uniquement par une carte RAM identique. Ne pas recharger ni brûler cette
pile. Les cartes RAM usagées doivent être éliminées conformément aux
réglementations locales.
Page 22
SAFETY AND ECOLOGICAL NOTES FOR DISPOSAL
1. Dispose of replaced parts in accordance with local regulations.
2. Used ink and masters should be disposed of in an environmentally safe
manner and in accordance with local regulations.
3. When keeping used lithium batte ries (from the main proce ssing units) in orde r
to dispose of them later, do not store more than 100 batteries (from the main
processing units) per sealed box. Storing larger numbers or not sealing them
apart may lead to chemical reactions and heat build-up.
Page 23
OVERALL INFORMATION
Rev. 08/2000
C237 OVERALL INFORMATION
DETAILED SECTION DESCRIPTIONS
C237 DETAILED SECTION DESCRIPTIONS
INSTALLATION
C237 INSTALLATION
SERVICE TABLES
C237 SERVICE TABLES
TAB
POSITION 1
TAB
POSITION 2
TAB
POSITION 3
TAB
POSITION 4
PREVENTIVE MAINTENANCE
C237 PREVENTIVE MAINTENANCE
REPLACEMENT AND ADJUSTMENT
C237 REPLACEMENT AND ADJUSTMENT
TAPE MARKER C532
PRIPORT CONTROLLER USER'S GUIDE
TAB
POSITION 5
TAB
POSITION 6
TAB
POSITION 7
TAB
POSITION 8
Page 24
Page 25
OVERALL
INFORMATION
Page 26
Page 27
1
1. OVERALL INFORMATION
SPECIFICATION
1.1 SPECIFICATION
Configuration: Desktop
Master Processing: Digital with 300 dpi thermal head
Scanning (Pixel Density): Contact image sensor (300 dpi), with xenon lamp
* In Fine mode, 400 dpi in the sub-scanning
resolution
Printing Process: Fully automatic one-drum stencil system
Original Type: Sheet/Book
In Platen Mode: Document size:
Maximum 257 x 364 mm [10.2" x 14.4"]
Thickness: Less than 30 mm
Weight: Less than 5 kg
In ADF Mode: Document size:
Maximum 257 x 364 mm [10.2" x 14.4"]
Minimum 148 x 105 mm [5.8" x 4.1"]
Overall
Information
Document weight:
50 - 90 g/m2 [13.3 - 23.9 lb]
(40 - 120 g/m2 [10.6 - 31.9 lb]
in single sheet feed)
ADF capacity:
30 sheets (using 20 lb or 80 g/m2 paper)
Reproduction Ratios: Inch version Others
Full Size: 100% 100%
Reduction: 65% 71%
74% 82%
77% 87%
93% 93%
Enlargement: 121% 115%
129% 122%
155% 141%
Image Modes: Letter, Photo, Letter/Photo, Fine, Tint
SM C231/C237
-1
Page 28
SPECIFICATION
1
Printing Area:
(At 20 °C/ 65 % RH)
B4 size drum models:
250 mm x 355 mm
Legal size drum models:
210 mm x 355 mm [8.2" x 13.9"]
A4 size drum models:
210 mm x 288 mm [8.2" x 11.3"]
Edge Margins: Leading edge:
5 ± 3 mm (At the "0" position of Image Shift mode)
Trailing edge:
2 mm
Print Paper Size: Minimum: 90 mm x 148 mm [3.6" x 5.9"]
Maximum: 267 mm x 390 mm [10.5" x 15.3"]
Print Paper Weight: 47.1 g/m2 to 157.0 g/m2 [12.5 lb to 41.7 lb]
Printing Speed: 80, 100, 120 sheets/minute (3 steps)
Master Process Time: Platen mode:
Less than 28 seconds (A4 paper)
ADF mode:
Less than 30 seconds (A4 paper)
Master Eject Box Capacity: 40 masters (Normal conditions)
(30 masters at low temperatures)
Side Registration Adjustable
±
10 mm
Range:
Vertical Registration Adjustable
±
10 mm
Range:
Paper Feed Table Capacity: 1000 sheets (80 g/m2 / 20 lb)
2
Paper Delivery Table Capacity: 1000 sheets (80 g/m
/ 20 lb)
Power Source: 110/120 V, 50/60 Hz: 2.5 A
220 - 240 V, 50/60 Hz: 1.5 A
Maximum Power Consumption: 250 W
Noise Emission:
(At operation position)
At 80 rpm printing speed: 71 dB
At 100 rpm printing speed:72 dB
At 120 rpm printing speed:72 dB
C231/C237 SM
-2
Page 29
1
Weight: 65 kg [143.3 lb]
68 kg [149.9 lb] with ADF
Dimensions:
(Width x Depth x Height)
Trays closed: 594 mm x 601 mm x 567 mm
With ADF:
594 mm x 601 mm x 617 mm
Trays open: 1187 mm x 601 mm x 567 mm
With ADF:
1187 mm x 601 mm x 617 mm
Master Type: Master for B4 drum
Thermal master roll type:
280 mm width, 125 m/roll
Yield:
260 masters/roll
Max run length per master:
2,000 prints
SPECIFICATION
Overall
Information
Master for A4/Legal drum
Thermal master roll type:
240 mm width, 125 m/roll
Yield:
300 masters/roll (A4 drum)
260 masters/roll (Legal drum)
Max run length per master:
2,000 prints
Master Storage Conditions: Temperature:
0 °C to 40 °C
Humidity:
10% to 95% RH
Recommended maximum storage period:
One year after production date
* Avoid locations exposed to direct sunlight.
SM C231/C237
-3
Page 30
SPECIFICATION
1
Ink Type 600 ml cartridge type
Available colors:
Black, Red, Blue, Green, Brown
Ink Storage Conditions: Temperature:
-5 °C to 40 °C
(Optimum conditions: 15 °C to 25 °C)
Humidity:
10% to 95% RH
(Optimum conditions: 20% to 70% RH)
Recommended maximum storage period:
One year after production date
* Avoid locations exposed to direct sunlight.
•
Available Options
Color Drum
•
Document Feeder
•
Key Counter
•
Tape Marker
•
PC Controller
C231/C237 SM
-4
Page 31
GUIDE TO COMPONENTS AND THEIR FUNCTION
1
1.2 GUIDE TO COMPONENTS AND THEIR FUNCTION
1.2.1 MACHINE EXTERIOR
Overall
Information
1. Front Door
2. Operation Panel
3. Platen Cover
4. Original Table Release
Lever
5. Feed Roller Pressure
Lever
6. Paper Feed Side Plates
7. Paper Feed Table
8. Side Table Fine Adjusting
Dial
9. Paper Feed Table Down
key
10. Behind Cover
C231V504.WMF
Open for access to the inside of t he machine.
Operator controls and indicators are locat ed her e.
Lower this cover over an original before printing .
Use to open the original table unit when installing t he
master.
Use to adjust the contact pressure of the paper feed
roller according to paper thickness.
Use to prevent paper skew.
Set paper on this table for print ing.
Use to shift the paper f eed t able sideways.
Press to lower the paper feed table.
Flip up when you wish to use the keys underneath.
SM C231/C237
-5
Page 32
GUIDE TO COMPONENTS AND THEIR FUNCTION
1
1.2.2 MACHINE INTERIOR
1. Document Feeder (Option)
2. Paper Delivery Side Plates
3. Paper Delivery End Plate
4. Paper Delivery Table
5. Main Switch
6. Drum Unit
7. Drum Unit Lock Lever
8. Ink Holder
C231V505.WMF
Originals inserted into the document feeder are
individually and automatically fed onto and
removed from the exposure glass.
Use to align the prints on the paper delivery table.
Use to align the leading edge of prints.
Completed prints are delivered here.
Use to turn the power on or off.
The master is wrapped around this unit.
Lift to unlock and pull out the drum unit.
Set the ink cartridge in t his holder .
C231/C237 SM
-6
Page 33
1
1.2.3 OPERATION PANEL
1
4
5
98101
1
131
2
GUIDE TO COMPONENTS AND THEIR FUNCTION
Keys
6
C231V511.WMF
2
7
1. Security key
Press to make prints of
confidential documents.
2. Paste Shadow Erase key
Press to erase the shadows on
images of pasted originals.
3. Tint key
Press to make prints in grey.
(This is the Tint/Economy key for
the China version.)
3
1
2
4
15
21
0
Overall
Information
7. Center/Edge Erase key
Press to print book originals that
have a solid image on the center
or edges.
8. Scroll keys
Press to select size and direction
of paper or original for
Center/Edge Erase.
9. Reduce key
Press to reduce the image.
4. Image Density key
Press to make prints darker or
lighter.
5. Check Indicator
This indicator lights when you
have selected one or more of the
functions accessed by lifting the
behind cover and pressing the
keys underneath (e. g. Security
key, Paste Shadow Erase key
etc.). This lets you know whether
one or more of these functions is
selected, even if the cover is
lowered.
6. Skip Feed key
Press to select skip feed printing.
10. Full Size key
Press to make full size prints.
11. Enlarge key
Press to enlarge the image.
12. Economy key
Press to save ink. (This is the
Combine 2 Originals key for the
China version.)
13. Type of Original key
Press to select Letter, Photo, or
Letter/Photo mode.
14. Fine key
Press to select fine image mode.
15. Image Position key
Press to shift the image forwards
or backwards.
SM C231/C237
-7
Page 34
GUIDE TO COMPONENTS AND THEIR FUNCTION
1
2
2
2
2
1
1
1
1
2
6
7
9
8
16. Program key
Press to input or recall user
programs.
17. Clear Modes key
Press to clear the previously
entered job settings.
18. Auto Cycle key
Use to process the master and
make prints automatically.
19. Proof key
Press to make proof prints.
20. Speed keys
Press to adjust the printing
speed.
21. Memory/Class key
Press to select Memory or Class
mode.
4
3
1
C231V511.WMF
5
22. Number keys
Press to enter the desired
number of prints and data for
selected modes.
23. # key
Use to enter data in selected
modes.
24. Clear/Stop key
While entering numbers, press to
cancel a number you have
entered. While copying, press to
stop copying.
25. Start key
Press to make a master.
26. Print key
Press to start printing.
6
C231/C237 SM
-8
Page 35
1
Indicators
1
2
3
4
5
GUIDE TO COMPONENTS AND THEIR FUNCTION
Overall
Information
1. Error indicators
These indicators are lit when a
non-standard condition occurs
within the machine.
2. Memory/Class Indicator
Shows the number entered in
Memory or Class mode.
3. Speed indicator
These indicators show the
printing speed that is selected.
4. Counter
Displays the number of prints
entered. While printing, it shows
the number of prints remaining.
5. Guidance Display
Display the machine's condition.
SM C231/C237
-9
Page 36
PRINTING PROCESS
1
5
4
1
1.3 PRINTING PROCESS
2
3
C231V500.WMF
6
1. Master Eject: Ejects the used master wrapped around the drum
into the master eject box.
2. Scanning: The scanner, which is composed of the contact
image sensor (CIS) and xenon lamp, scans the
original image.
3. Master Feeding: Converts the image signal read by the CIS into digital
signals and sends them to the thermal head to
develop the image on the master. The master is then
wrapped around the drum.
4. Paper Feeding: Sends paper to the drum section.
5. Printing: Presses the paper fed from the paper feed section to
the drum. This transfers the ink onto the paper
through the drum screen and the master.
6. Paper Delivering: Peels the printed paper with the exit pawl and air
knife, and ejects the paper onto the paper delivery
table.
C231/C237 SM
-10
Page 37
MECHANICAL COMPONENT LAYOUT
1
123
252
10111
1
1.4 MECHANICAL COMPONENT LAYOUT
4232221
20
19
18
17
Overall
Information
4
5
6
7
8
9
16
1. Tension Roller
2. Master Feed Roller
3. Platen Roller
4. Scanner
5. Master Roll
6. Thermal Head
7. Paper Feed Roller
8. Paper Pick-up Roller
9. Paper Table
10. Registration Roller
11. Doctor Roller
C231V500.WMF
3
21415
14. Vacuum Fan Motor
15. Transport Belts
16. Paper Delivery Table
17. Air Knife Fan Motor
18. Master Eject Roller
19. Master Eject Box
20. DF R1 Roller
21. DF R0 Roller
22. DF Separation Roller
23. DF Document Feed Roller
24. DF Pick-up Roller
12. Ink Roller
25. DF R2 Roller
13. Press Roller
SM C231/C237
-11
Page 38
ELECTRICAL COMPONENT LAYOUT
1
2
3
1.5 ELECTRICAL COMPONENT LAYOUT
1.5.1 ADF
1
Motors
Index No. Name Function
4 ADF Motor Drives the original.
4
5
6
C231V508.WMF
Switches
Index No. Name Function
3 ADF Cover Switch Detects whether the ADF cover is open or
closed.
5 ADF Switch Detects whether the ADF unit is open or closed.
Sensors
Index No. Name Function
2 Scan Line Sensor Detects when a page is approaching the auto
shading position.
1 Document Sensor Detects the presence of a document in the
feeder.
6 Not Used
C231/C237 SM
-12
Page 39
1
1.5.2 MAIN BODY
C
2
2
3
3
3
3839404
4
5
1236547
1
1
1
5
25
24
ELECTRICAL COMPONENT LAYOUT
Overall
Information
8
9
23
22
21
48
47
20
9
49
18
50
17
10
11
12
13
14
5
6
1
2
C231V501.WMF
6
7
28
29
30
46
31
32
45
33
34
44
3
42
231V503.WMF
SM C231/C237
1
-13
7
5
6
Page 40
ELECTRICAL COMPONENT LAYOUT
1
Boards
Index No. Name Function
2 Main Processing Unit
(MPU)
3 Lamp Stabilizer This supplies power to the xenon lamp.
17 Power Supply Unit Provides dc power to the system.
25 Operation Panel Boards These boards control the operation panel.
4 Contact Image Sensor
and Xenon Lamp
40 Noise Filter Board Filters out electrical noise on the ac power input
42 Mai n Moto r Con trol
Board
Controls all machine functions both direct ly and
through other boards.
This sensor reads and converts the light
reflected from t he docum ent into an analog
video signal. It uses an RMLA (Roof Mirror Lens
Array) sensor unit.
The xenon lamp that illuminates the document is
contained in this unit.
lines.
Controls the main motor speed.
Motors
Index No. Name Function
7 Master Feed Motor Feeds the master to the drum.
18 Cutter Motor Cuts the master.
19 Registration Motor Feeds the paper to align it with the master on
the drum.
1 Scanner Motor Stepper mot or dr ives the book scanner.
30 Master Eject Motor Sends used mast ers into the master eject box.
31 Air Knife Fan Motor Rotates the fan to provide air t o separate the
leading edge of the paper from the drum.
34 Pressure Plate Motor Raises and lowers the pressure plate.
35 Vacuum Fan Motor Provides suction so that paper is held firmly on
the transport belt.
36 Paper Transport Motor Transports the printed paper.
39 Clamper Motor Opens or closes the drum master clamper.
44 Main Motor Drives paper feed mechanisms and the drum.
46 Paper Table Motor Raises and lowers the paper table.
52 Ink Pump Motor Drives the ink pump.
C231/C237 SM
-14
Page 41
ELECTRICAL COMPONENT LAYOUT
1
Solenoids
Index No. Name Function
43 Rear Pressure Release
Solenoid
20 Front Pressure Release
Solenoid
Releases the press roller to apply printing
pressure.
Releases the press roller to apply printing
pressure.
Switches
Index No. Name Function
49 Scanner Unit Safety
Switch
9 Master Making Unit
Cover Safety Switch
16 Table Lowering Switch Lowers the paper table.
21 Test Switch Releases the cover safety functions. (See the
23 Door Safety Switch Check s whether the front door is properly
24 Main Switch Turns the power on or off.
Checks whether the scanner unit is properly set.
Checks whether the cover on the master making
unit is properly closed.
notes below this table.)
closed.
Overall
Information
NOTE:
When you use this test switch, be sure to return it to the default position
after servicing.
Sensors
Index No. Name Function
50 Master Eject Position
Sensor
51 Paper Exit Timing
Sensor
48 Feed Start Timing
Sensor
26 Master Eject Sensor Detect s used master misfeeds.
28 Pressure Plate Limit
Sensor
27 Pressure Plate Home
Position Sensor
29 Drum Master Sensor Detects if there is a master on t he dr um .
32 Eject Box Set Sensor Checks if the master eject box is set.
33 Paper Exit Sensor Detects paper misfeeds at the exit.
37 2nd Feed Timing
Sensor
38 Clamper Open Sensor Detects if the clamper is in the open position.
41 Clamper Close Sensor Detects if the clamper is in the closed position.
45 Table Lower Limit
Sensor
Detects when the drum is at the master eject
position.
Determines the paper exit misfeed check t im ing .
Determines the paper feed start t im ing .
Detects if the pressure plate is in t he lowest
position.
Detects if the pressure plate is at t he hom e
position.
Determines the paper misfeed check t im ing at
the paper registration area.
Detects when the paper table is at its lower limit
position.
SM C231/C237
-15
Page 42
ELECTRICAL COMPONENT LAYOUT
1
Index No. Name Function
5 Platen Cover Sensor Detects whether the platen cover is open or
closed.
6 Scanner Home Position
Sensor
8 Master Set Cover
Detects when the image sensor is at home
position.
Checks if the master set cover is set.
Sensor
10 Master End Sensor I nforms the CPU when the master mak ing unit
runs out of master roll.
11 Paper Height Sensor Detects when the paper table reaches the paper
feed position.
13 Paper Registration
Sensor
Detects paper approaching the registr ation
roller.
15 Paper End Sensor Informs the CPU when the paper table runs out
of paper.
14 Cutter Home Position
Detects when the cutter is at the home position.
Sensor (Switch)
Counters
Index No. Name Function
22 Paper and Master
Counters
Keep track of the tot al num ber of copies and
masters made.
Others
Index No. Name Function
47 Paper Feed Clutch Transmits main motor drive to the paper feed
roller at the appropriate time.
12 Thermal Head Burns the image onto the master.
C231/C237 SM
-16
Page 43
1
1.6 DRIVE LAYOUT
3
4
8
7
DRIVE LAYOUT
Overall
Information
1
2
1. Pressure Plate Motor
2. Clamper Motor
3. Paper Transport Motor
4. Main Motor
C231V501.WMF
56
5. Registration Motor
6. Paper Table Motor
7. Paper Feed Clutch
8. Master Feed Motor
SM C231/C237
-17
Page 44
Page 45
DETAILED SECTION
DESCRIPTIONS
Page 46
Page 47
SCANNER AND OPTICS
[
2. DETAILED SECTION DESCRIPTIONS
2.1 SCANNER AND OPTICS
2.1.1 BOOK SCANNER OVERVIEW
[D]
[E]
I]
[C]
[H]
[A]
[B]
C231D500.WMF
The scanner motor [A] drives the scanner [B] through the timing belt [C] and drive
wire [D]. The shaft [E] guides the scanner movement in the sub-scan direction.
The scanner [B] consists of a contact image sensor and a xenon lamp driver.
Detailed
Section
Descriptions
The scanner home position sensor [H] detects when the scanner returns to the
home position after scanning.
The platen cover switch [I] detects the cover status.
SM C231/C237
2-1
Page 48
SCANNER AND OPTICS
2.1.2 ADF OVERVIEW
[D]
[E]
[C]
[F]
[B]
[G]
[A]
C231D501.WMF
[I]
[H]
C231D572.WMF
The sheet through-type ADF feeds the document from the top of the document
stack.
The pick-up roller [A] and feed roller [B] feed the original into the scanner, and the
separation roller [C] helps to feed one sheet at a time. Then, the R0 [D], R1 [E],
and R2 [H] rollers feed the document through the scanner.
During scanning, the scanner [I] moves to the scanning position under the
exposure glass [G]. The shading plate [F] secures the document at the scan line,
ensuring that the document is within the image sensor's range of focus.
After scanning, the ADF feeds the document onto the platen cover, and the
scanner moves back to its home position.
C231/C237 SM
2-2
Page 49
[A]
[B]
SCANNER AND OPTICS
C231D502.WMF
Detailed
Section
Descriptions
The document sensor [A] detects when an original is placed in the ADF. The
sensor [B] is not used in this unit. The ADF is a common part which is used in other
models.
SM C231/C237
2-3
Page 50
SCANNER AND OPTICS
2.1.3 CONTACT IMAGE SENSOR
[D]
[A]
[C]
[B]
[F]
[E]
C231D503.WMF
The contact image sensor (CIS) assembly [A] consists of the exposure glass [B],
roof mirror lens array [C], xenon lamp [D], and the image sensor [E].
The CIS moves under the exposure glass when scanning a book original, and
remains stationary at the ADF scan line when scanning a sheet original using the
ADF.
The image sensor is a row of 4096 photosensitive elements (B4 width x 16
dots/mm). The roof mirror lens array focuses the light reflected from the document
onto the image sensor.
Due to the short optical path of a CIS unit, the focal depth is much shorter than in a
CCD type scanner. Because of this, two springs are used to push the CIS against
the exposure glass [F], to keep the distance between the CIS and the original
constant. In book scanning mode, if the original is out of the CIS focal range,
however, the scanned image may be darkened.
NOTE:
Due to the characteristics of the CIS, shadows of a paste-up original tend
to appear on copies. To counter this, press the paste shadow erase key on
the operation panel to use the paste shadow erase mode.
The strength of the paste shadow erase level can be changed with SP no.
28.
C231/C237 SM
2-4
Page 51
2.1.4 DRIVE MECHANISM
Book Scanner
[D]
[C]
[A]
[G]
SCANNER AND OPTICS
[E]
[B]
Detailed
Section
Descriptions
[F]
C231D504.WMF
The book scanner motor [A] drives the scanner [B] via a timing belt [C] and drive
wire [D]. The scanner moves along the guide shaft [E].
The springs [F] apply pressure to the contact image sensor [G] to ensure that the
distance from the image sensor to the exposure glass surface remains constant
during scanning.
SM C231/C237
2-5
Page 52
SCANNER AND OPTICS
ADF
[D]
[A]
[C]
[B]
[E]
C231D505.WMF
The ADF motor [A] drives the pick-up roller [B], the feed roller [C], the R0 roller [D],
the R1 roller (not shown), and the R2 roller [E].
C231/C237 SM
2-6
Page 53
2.1.5 PI CK-UP AND FEED (ADF)
[A]
C231D507.WMF
[B]
SCANNER AND OPTICS
Detailed
Section
Descriptions
C231D506.WMF
When the ADF m otor starts, the mechanical clutch [A ] engages and lowers t he
pick-up roller [B] into contact with the document. Then the machine begins feeding
the original stack, beginning with the top page. After the last page is scanned, the
ADF motor reverses briefly to raise the pick-up roller back to the standby position.
SM C231/C237
2-7
Page 54
SCANNER AND OPTICS
2.1.6 SEPARATION MECHANISM (ADF)
[A]
[B]
C231D508.WMF
The feed roller [A] and the separation roller [B] prevent more than one sheet of
paper from feeding into the scanner at the same time.
When the feed roller feeds a sheet of paper, both the feed and the separation
rollers rotate in the feed-in direction. However, if two or more sheets are between
these rollers, the separation roller rotates in the feed-out direction to prevent the
lower sheet from being fed into the scanner.
C231/C237 SM
2-8
Page 55
SCANNER AND OPTICS
2.1.7 ERROR CONDITIONS
Book Scanner
The main CPU detects an error (error code E-13 is displayed) if either of the
following conditions occurs.
Condition Description Error Code
The scanner home position sensor does not
turn on within 7 seconds after the motor
engages.
Home position sensor
error condition
ADF
The scanner home position sensor does not
turn off within 4 seconds after power on.
Otherwise, when the scanner could not
return to the home position within 2
seconds of leaving.
E-13
Detailed
Section
Descriptions
"Paper feed jam" is displayed if any of the following conditions occurs.
Jam Condition Description
Non-feed
Misfeed 1
Misfeed 2
The scan line sensor does not switch on within 5 seconds after the
ADF motor starts.
The scan line sensor does not turn off even when the paper (a trial
print) reaches the registration area.
The ADF motor reverses after the last document feeds out of the
scanner or after a jam is cleared. At this time, the misfeed 2 error
condition occurs if the document sensor stays on.
SM C231/C237
2-9
Page 56
IMAGE-PROCESSING
2.2 IMAGE-PROCESSING
2.2.1 OVERVIEW
Main Processing Unit (MPU)
Contact Image
Sensor
Power Supply
PCB
Thermal
Head
Amplification
GA2
Thermal
Head
Drive
A/D
Conversion
Data
Compensation
Clock
Overlay
Letter/Photo
Image Area
Detection
MTF
Correction
Main-scan Direction
Image Position
Adjustment
Data Selection
Selection
GA1
Centering
Thresholding
Data
Diffusion
Control
Half Tone Processor
Error
Main
Data
Selection
Image
Enlargement/
Reduction
C231D509.WMF
This model uses a contact image sensor (CIS) instead of a CCD. It removes the
necessity for the complicated adjustments that are needed for a CCD scanner.
There are three main chips on the main processing unit (MPU) as shown. The
halftone processor chip enables the use of Letter/Photo mode in addition to Letter
and Photo modes. In Letter/Photo and Phot o mod es, error di ffusio n proc essi ng
produces better copy quality halftone images.
The halftone processor also includes the A/D conversion function, as well as the
image processing functions. The thermal head drive function is built into a chip
(GA2) on the MPU.
C231/C237 SM
2-10
Page 57
IMAGE-PROCESSING
2.2.2 A/D CONVERSION PROCESSING
The analog signal from the contact image sensor is converted into a digital signal
that represents 64 grayscale steps. This process is carried out in the halftone
processing chip in the MPU.
Shading Distortion Correction
The image data from one main scan line does not exactly represent the line from
the original image, because of the following reasons:
1) Loss of brightness towards the ends of the exposure lamp.
2) Variations in sensitivity among elements of the contact image sensor
3) Distortions of the light path
Detailed
Section
Descriptions
CIS
CIS
C231D510.WMF
Such distortions in the image data are corrected when they are converted into
digital data.
Before scanning the document, the scanner reads the white plate on the back of
the original scale. The output of each contact image sensor element is changed to
a 6-bit digital value and is stored in the shading distortion memory.
To change the analog shading distortion signals to digital data, a scale of 64 steps
is made between the whitest level when the white plate is scanned and 50% of the
whitest level. Using this scale, the analog signal is changed to 6-bit digital data.
While an original is scanned, the 6-bit shading distortion value for each pixel is
sent, in series, from memory to the D/A converter, synchronizing with the image
signal being sent to the A/D converter. The D/A converter changes the distortion
value to an electrical current. The current is converted to the voltage to be used as
high reference data for A/D conversion. In this way, the high reference voltage for
A/D conversion is changed sequentially for each pixel depending on the shading
distortion data for that pixel.
SM C231/C237
2-11
Page 58
IMAGE-PROCESSING
Original Background Correction
When an origin al is scanned, the whitest level of the original background is stored,
and that level is used as the white peak level for A/D conversion. The grayscale is
made based on the white peak level of the original. As a result, dark background
does not appear on the printout.
If the original background correction is disabled, the whitest level when the white
plate is scanned is used for the high reference voltage.
C231D512.WMF
Peak Hold
The peak hold circuit holds the voltage for the white peak level. Before scanning an
original, it holds the white peak voltage from the white plate to make shading
distortion data. When the original is scanned, it stores the white peak level of the
original for the original background correction.
NOTE:
The white peak level is checked 5 mm from the leading edge of the original
set on the exposure glass (and from the central 147-mm width). If the
original leading edge is not flush with the original scale and the platen
cover stays open, insufficient voltage will be input as the white peak level.
If insufficient voltage is detected, a fixed voltage is used as the white peak
level to avoid a faint image copy.
C231/C237 SM
2-12
Page 59
IMAGE-PROCESSING
2.2.3 BINARY PROCESSING
In the halftone-processing chip, the 6-bit digital signal data is generated in the A/D
conversion circuit and is sent to the binary processing circuit. At that time the data
is inverted to match the binary processing circuit. Therefore, the white peak level
becomes 0, and the black level becomes 63.
In the binary processing circuit, the 6-bit data is converted into 1-bit data for black
or white pixels. The binary processing for the letter and photo is different, as
follows:
Letter Mode, Letter areas in Letter/Photo Mode: MTF (Modulation Transfer
Function) Correction
Photo Mode, Photo areas in Letter/Photo Mode: Error Diffusion Processing
Data Compensation Processing
In this process, the 6-bit data are converted based on a compensation curve
(gamma curve) which corresponds to selected image settings. For example, if a
darker image is selected, a compensation curve, which converts each pixel value
to a higher number, is selected. The output data is still 6-bit.
Detailed
Section
Descriptions
Input
6-bit data from
the A/D conversion
PCB
Gamma curve
selection signal
Data
Compensation
Circuit
Output
6-bit data
C231D514.WMF
C231D515.WMF
SM C231/C237
2-13
Page 60
IMAGE-PROCESSING
MTF Correction
When the original image is converted to electrical signals by the c ontact image
sensor, the contrast is reduced. This is because neighboring black and white parts
of the image influence each other. This symptom is typical when the width and
spacing between black and white areas are narrow. MTF correction counters this
symptom and emphasizes image detail. The value of a target pixel is modified
depending on the value of surrounding pixels. The modified data is compared with
a threshold level. This determines if the pixel is to be black or white.
After the MTF correction is done, the corrected data is compared with the black or
white threshold level. If a pixel value is above the threshold level, it is set to black.
If the pixel value is equal or below the threshold level, it is set to white. The
threshold level depends on the selected density setting.
Image Density
Setting
Lighter 28 35
Normal 35 40
Darker 1 38 42
Darker 2 42 44
Threshold Level for Line
Mode
Threshold Level for Line
Areas in Line/Photo Mode
Binary Processing in Letter/Photo Mode
In the Letter/Photo mode, the machine checks each pixel of the original to see if
the pixel is in a letter area or in a photo area. To distinguish letter and photo areas,
the CPU does the calculation on the 6-bit pixel data.
If the CPU recognizes that the pixel is in a letter area of the image, it uses the MTF
process to convert the 6-bit value to 1-bit.
If the CPU recognizes that the pixel is in a photo area of the image, the pixel is
converted to 1-bit using error diffusion.
To emphasize characters in a photo original when using Letter/Photo mode, a data
compensation curve (γ curve) is used to make a darker image.
C231/C237 SM
2-14
Page 61
IMAGE-PROCESSING
Error Diffusion
Error diffusion is used to reproduce halftone images in photo mode.
Before a 6-bit image signal is converted into a single-bit signal based on the
threshold level, there is a difference between the image signal value and the
complete black value (63 for a 6-bit signal) or white value (0). With the error
diffusion process, the difference is distributed among the surrounding pixels. (The
MTF process simply erases these differences.)
When consid ering error diffusion in one dimension only (acros s the page), the 6-bit
data shown in the example below produces white and black data output as shown
below. In practice, this one-dimensional error diffusion is done in all directions on
each pixel (across the page, down the page, etc.).
Image data from one scan line
711132130384144
Detailed
Section
Descriptions
C231D518.WMF
In each dimension, the difference between the pixel value and the nearest extreme
(0 or 63) is transferred to the next pixel. The 1st pixel in the row becomes either
black or white, whichever is closest. Then, in the example above, the difference
between 7 and 0 is added to the 2nd pixel. The value of the 2nd pixel, which is now
18, is then added to the 3rd pixel. The 4th pixel becomes 52, which is closer to 63
than 0. In such cases, the difference is subtracted (not added) to get the next pixel
value. In this example, the difference is 63-52=11, and the next pixel value (30-11)
becomes 19.
SM C231/C237
2-15
Page 62
IMAGE-PROCESSING
2.2.4 MAIN SCAN MAGNIFICATION
Scanned Data
Points
Calculated Data
Points
Reduced Image
Data Points
Scanned Data
Points
Calculated Data
Points
Reduced Image
Data Points
Changing the original transport speed performs the reduction and enlargement in
the sub-scanning direction. Reduction and enlargement in the main scanning
direction is handled by the magnification and image shift processing circui ts.
C231D520.WMF
Pixels for scanning and master making are generated at fixed intervals (the contact
image sensor and thermal head element intervals). The image is scanned at the
contact image sensor element interval. If pixels on the master are made at the
same interval (by the thermal head elements) then the master image is the same
size as the original.
When actual pixels are divided in accordance with a magnification ratio, the
magnification processor calculates the imaginary point values that would
correspond to new pixels. The proper value for each imaginary point is calculated
based on the image data of the surrounding pixel values.
- 80 % Reduction For example, the contact image sensor scans data for 10 pixels in a main scan
line. Those data are compressed into data for 8 pixels by the magnification
processor. As a result, the image is reduced to 80 %.
- 140 % Enlargement Data for 10 pixels of a main scan line are expanded into data for 14 pixels. As a
result the image is enlarged with a 140 % magnification ratio.
C231/C237 SM
2-16
Page 63
IMAGE-PROCESSING
2.2.5 IMAGE POSITION ADJUSTMENT IN THE MAIN SCAN
DIRECTION
To adjust the image position of the original across the printout, the image can be
shifted ± 1.9 mm in the main scan direction using SP mode No. 31 (platen mode)
or No. 37 (ADF mode).
The image shift in the main scan direction is done by changing the relationship
between the position of the image data on the CIS and on the thermal head. Data
for one main scan line is stored in a line memory. When the data is output from
memory, the output timing is changed to shift the image.
CIS Center
3072
3072
3072
Data from CIS
After A/D Conversion
Data from
Thermal Head Driver,
No Image Shift
Data from
Thermal Head Driver,
Image Shift x mm
(SP 31 or 37)
0
Thermal Head
Center
0
x mm
0
Thermal Head
Center
Detailed
Section
Descriptions
C231D521.WMF
2.2.6 PASTE SHADOW ERASE MODE
Due to the characteristics of the contact image sensor, shadows of a paste-up
original tend to appear on copies. To counter this, the paste shadow erase mode
can be used by pressing the paste shadow erase key on the operation panel.
When this mode is selected, the black or white threshold level is slightly lowered.
At the same time, the emphasis in the sub-scan direction in the MTF correction
process is weakened to make the shadows inconspicuous.
The strength of the paste shadow erase level can be changed with SP No. 28.
SM C231/C237
2-17
Page 64
IMAGE-PROCESSING
2.2.7 THERMAL HEAD
Specifications
•
Length 260.2 mm
•
Number of thermal head elements 3072 dots
•
Density of thermal head elements 300 DPI
•
Applied voltage Approximately 21 volts
Thermal Head Control
The thermal head has heating elements at a density of 300 dpi. The thermal
heating elements melt the over-coating and polyester film layers of the master,
according to the image signal for each pixel.
The power supply unit applies power (VHD) to the thermal heating elements. The
power source varies from one head to another since the average resistance of
each element varies. Therefore, when the thermal head or power supply unit is
replaced, it is necessary to readjust the applied voltage with particular values for
each thermal head.
Thermal Head Protection
The thermistor on the thermal head provides thermal head protection, preventing
the thermal head from overheating when processing a solid image. The CPU
detects any abnormal condition when the Start key is pressed, and displays an SC
code on the operation panel as follows:
SC Code Conditions
E - 04
E - 09
E - 10 When the pulse width that controls the
Over 54°C
Under - 20°C (Normally, this indicates that
the thermistor has become open, or a
related connector is disconnected.)
thermal head energy becomes abnormal,
master making stops and this SC lights.
Detecting
Component
Thermistor
Thermistor
MPU
C231/C237 SM
2-18
Page 65
Remarks for Handling the Thermal Head
The following remarks must be noted when servicing:
Remove any foreign materials on
Do not touch the surface
•
with bare hands. If you
touch it, clean the surface
with alcohol.
Do not damage the
•
heating elements.
Platen
Master
•
the platen roller.
Remove foreign materials.
•
Do not touch the surface of the
•
IMAGE-PROCESSING
master film with bare hands.
Do not touch the terminals of
•
the connectors with bare
hands to prevent damage from
static electricity.
Detailed
Section
Descriptions
MPU
Thermal Head
Connect and disconnect the connectors
•
carefully. Keep them horizontal. Also,
make sure that they are reconnected
firmly.
Adjust the applied voltage to the
•
particular value for the thermal head.
Connector
PSU
- Other Remarks Avoid using the machine under humid conditions. Moisture tends to condense on
the thermal head, causing heating element damage.
SM C231/C237
2-19
Page 66
MASTER EJECT
[
2.3 MASTER EJECT
2.3.1 OVERALL
[C]
[B]
C231D531.WMF
[A]
B]
[C]
C231D530.WMF
At the end of the printing cycle, the used master remains wrapped around the drum
to prevent the ink on the drum surface from drying. When the Master Making key is
pressed to make a new master, the used master is removed from the drum.
The machine ensures that the drum is at the master eject position and a master is
on the drum by checking the drum master sensor. The master clamper [A] then
opens to eject the master. If there is no master on the drum, the machine skips the
master eject operation and proceeds to the master making process.
The master eject rollers [B] turn for 0.6 seconds and pick up the master's leading
edge. After closing the master clamper, the drum starts rotating at the slowest
speed (30 rpm). At the same time the master eject rollers turn to feed the used
master into the master eject box [C].
When the drum stops at the master feed position after one and a half turns, the
pressure plate drive motor starts turning to compress the used master into the
master eject box.
C231/C237 SM
2-20
Page 67
2.3.2 MASTER CLAMPER OPEN MECHANISM
[B]
MASTER EJECT
[A]
[H]
[D]
[I]
[G]
[C]
[F]
[E]
[J]
C231D557.WMF
The master eject position sensor [A] ensures that the drum is positioned at the
master eject position when the Start key is pressed.
The master clamper has a magnetic plate [C] to secure the master's leading edge
in the clamper. The clamper is fixed to the clamper shaft [D], which has a lever [E]
at the rear side.
Detailed
Section
Descriptions
The clamper motor [F] drives the moving link [G] and pushes the clamper lever
open [E]. (The link position, the clamper open and close positions, are detected by
the clamper open sensor [H] and clamper close sensor [I].)
The master clamper then lifts the master eject arm [J] to release the master's
leading edge from the clamper.
Drum Position Lock Mechanism
When the c lamper motor [ F] opens the clamper at the master eject position, th e
drum guide [B] moves and engages the pin on the rear flange of the drum.
The drum guide is moved by the same mechanism that drives the moving link [G].
This means that the drum guide captures the drum at the master eject position
when the master clamper is being opened.
When the c lamper motor turns on again to close the master clamper, the drum
guide also disengages the pin and the drum can now turn.
SM C231/C237
2-21
Page 68
MASTER EJECT
2.3.3 MASTER EJECT ROLLER MECHANISM
[B]
[C]
[A]
C231D532.WMF
The master eject rollers are driven by the master eject motor [A] through idle gears.
The upper eject roller [B] has paddles to assure the master pick-up.
When the master clamper is opened and the master's leading edge is released
from the master clamper, the master eject motor turns on for 0.6 seconds to pick
up the leading edge of the master.
When the master eject motor is turned off, the clampe r motor reverses to close the
master clamper.
The drum then starts turning at the slowest speed (30 rpm). At the same time, the
master eject rollers turn again to feed the master into the master eject box.
After one turn of the drum, the master eject motor stops. The drum turns for an
additional half turn, stopping 109 encoder pulses after the feed start timing sensor
is actuated (this means that the drum is at the master feed position).
The master eject sensor [C] is used to detect master eject jams.
C231/C237 SM
2-22
Page 69
2.3.4 PRESSURE PLATE MECHANISM
MASTER EJECT
[A]
[E]
[D]
[B]
[C]
C231D533.WMF
[C]
[B]
[F]
Detailed
Section
Descriptions
The pressure plate motor [A] drives the pressure plate through the drive arm [B]
and the pressure springs [C].
When the master has been ejecte d into the master eject box, the pressure plate
motor turns until the actuator on the pressure plate [E] actuates the pressure plate
limit sensor [D]. When the limit sensor is actuated, the motor sto ps. When master
making and cutting are completed, the motor turns in the reverse direction to return
the pressure plate to the home position. When the pressure plate home position
sensor [F] is actuated, the motor stops.
If the pressure plate limit sensor is not actuated within 2.8 seconds after the
pressure plate motor is activated, the machine determines that the eject box is full
and that the pressure plate cannot travel any more. In this case, the machine
determines that the complete master has been fed into the box and stops the
motor (after returning the pressure plate to the home position). The Empty Master
Eject Box indicator lights when the drum returns to the home position at the end of
the next master making process.
SM C231/C237
2-23
Page 70
MASTER FEED
2.4 MASTER FEED
2.4.1 OVERALL
[A]
[C]
[B]
[E]
[D]
C231D534.WMF
The master is fed by the platen roller [A] while the thermal head [B] develops the
image on it. When the drum is at the master feed position and the master clamper
is opened, the tension roller [C] is moved away by the master clamper so that the
master's leading edge can be fed to the master clamper [D]. The leading edge of
the master is clamped by the master clamper, and the master is wrapped around
the drum and cut by the cutter [E] to the desired length.
This model uses a new master setting mechanism. This eliminates need for the
operator to manually cut the master, unlike the other models.
C231/C237 SM
2-24
Page 71
2.4.2 MASTER FEED MECHANISM
[B]
MASTER FEED
Detailed
Section
Descriptions
C231D536.WMF
[C]
[D]
[A]
C231D535.WMF
A stepper motor (the master feed motor [A]) drives the platen roller [B]. The thermal
head is pressed against the platen roller by the pressure springs. The pressure is
applied when the master set cover, which includes the platen roller, is closed.
After the master is ejected, the drum stops at the master feed position and the
master clamper opens, ready to clamp the new master.
The leading edge of the master is stopped on the guide plate after the last master
cutting operation or after a new master roll has been installed. The master is then
fed for 52.4 mm and stopped briefly to synchronize with original feed. The master is
fed for a further 67.5 mm before the master clamper is closed. Since the clamper
closes after the master's leading edge reaches the clamper, a buckle [C] is made in
the master above the master feed guide. This buckle absorbs the shocks from the
master clamping operation.
The drum then turns intermittently in the slowest mode (30 rpm) to wrap the master
around the drum. The intermittent rotation keeps a buckle in the master above the
master feed guide to absorb shocks from the wrapping operation. The tension roller
[D] is pressed against the guide plate to keep the master under tension during the
master wrapping operation.
SM C231/C237
2-25
Page 72
MASTER FEED
2.4.3 MASTER CLAMPER OPERATION AND TENSION ROLLER
RELEASE MECHANISM
[B]
[A]
[D]
[C]
[E]
C231D537.WMF
After the master has been ejected, the drum is stopped at the master feed position.
At this time, the clamper motor [A] drives the moving link [B] to open the master
clamper [C].
The tension roller [D] is normally pressed against the master feed guide plate to
apply tension to the master during the master wrapping operation. When the
clamper opens, the clamper pushes the tension roller arms [E] and moves the
tension roller away from the guide plate to allow the master to be fed into the
master clamper.
To close the master clamper, the clamper motor reverses.
NOTE:
The clamper open and close sensors identifies the link [B] position. Refer
to the Master Eject section for details.
C231/C237 SM
2-26
Page 73
2.4.4 CUTTER MECHANISM
[C][A][
[E]
B]
MASTER FEED
Detailed
Section
Descriptions
C231D573.WMF
[D]
After the master making process finishes, the master feed motor turns off and the
cutter starts running to cut the master to the desired length.
The cutter motor [D] drives the screw shaft [A], moving the cutter holder [C]
backwards and forwards.
There are two cutter blades [B] in the holder. The master is cut while the cutter
holder [C] travels towards the rear (the non-operation side of the machine). The
cuter motor keeps turning in one direction. The cutter holder return s to the home
position when it reaches the rear end of the cutter unit and reverses direction
because of the two different spirals threaded on the screw shaft [A].
When the cutter holder re aches the home position, the holder activates the cutter
home position sensor (switch) [E] and the motor stops.
After the master cut operation, the drum starts turning again to wrap the remaining
part of the master around the drum. The leading edge of the master that was cut
remains at the cutting position, ready to make the next master.
SM C231/C237
2-27
Page 74
DRUM
2.5 DRUM
2.5.1 OVERALL
[A]
[B]
[C]
[F]
[D]
[E]
C231D538.WMF
The drum consists of a metal screen [A] and a cloth screen [B].
The ink pump, which is installed inside the drum, supplies ink from the ink cartridge
into the drum through the drum shaft [C]. Ink is then evenly spread on the screens
by the ink [D] and doctor [E] rollers. Ink passes to the paper through the holes
(image) in the master [F], which was made by the thermal head.
The drum is driven by the main motor and turns only clockwise (as viewed from the
operator side). The motor speed and the drum stop positions are controlled by
monitoring the motor encoder.
C231/C237 SM
2-28
Page 75
2.5.2 DRUM DRIVE MECHANISM
[E]
[F]
DRUM
Detailed
Section
Descriptions
[D]
[A]
[C]
[B]
C231D539.WMF
The drum is driven by the main motor (a dc motor) through a timing belt [A] and
gears [B]. The main motor has an encoder (not shown) which sends pulses to the
main motor control board. The CPU on the board monitors the pulses and controls
the drum speed and stop positions.
The drum has two stop positions: the master eject (drum home) position and the
master feed position. These stop posi ti o ns are det er min ed by checking the feed
start timing sensor [C]. The CPU starts counting the main motor encoder pulses
after the feed start timing sensor is actuated.
When the dr um is stopped at the maste r eject position, the master eject position
sensor [D] is actuated. When the master eject operation is started, the CPU
confirms that the drum is at the master eject position by checking this sensor.
There are other two sensors that check the drum position. The paper exit timing
sensor [E] and 2nd feed timing sensor [F] which are used to send the CPU (on the
MPU) the paper jam detection timing signals of the paper exit and the registration
area. (The actual jam checking is performed by the paper exit sensor and
registration sensor.)
SM C231/C237
2-29
Page 76
DRUM
2.5.3 INK SUPPLY MECHANISM
[A]
[B]
[E]
[C]
[F]
[D]
C231D540.WMF
Ink is supplied from the ink cartridge to the ink roller [B] by a pump [C]. The ink
pump is driven by the ink supply motor (a dc motor) [D]. There is a pin on the pump
drive gear [E] which is coupled with the pin holder [F] on the pump piston shaft.
This mechanism converts the gear rotation into a piston motion.
Ink drops through the holes in the drum shaft [A] and onto the ink roller [B].
NOTE:
There are 4 holes in the shaft for the B4 size drum models, and two holes
for the Legal and A4 drum versions.
C231/C237 SM
2-30
Page 77
2.5.4 INK ROLLER MECHANISM
[C]
[D]
DRUM
Detailed
Section
Descriptions
[A]
[B]
[E]
C231D541.WMF
[F]
The ink roller [A] and the doctor roller [B] are driven by the gear [C] on the drum
shaft. Ink on the ink roller is squeezed by the doctor roller to produce an even
thickness of ink across the ink roller surface. The ink roller drive gear [D] has a
one-way clutch to prevent the ink roller from being turned in the reverse direction
when the drum is manually turned in the reverse direction.
The ink roller does not touch the screen [E] when the machine is not printing.
However, during the printing process, the ink on the ink roller is applied to the
paper through the holes in the screens and the master. This happens when the
press roller [F] located underneath the drum moves upward to press the paper, the
drum screens and the master against the ink roller.
SM C231/C237
2-31
Page 78
DRUM
2.5.5 INK SUPPLY CONTROL
[B]
[C]
[A]
[D]
C231D542.WMF
The ink detecting pins [A] work like the electrode of a capacitor and detect the
capacitance between the detection pins and the ink [B] located on top of the doctor
[C] roller. The capacitance is different when the ink level is high and the pins touch
ink, compared to when the ink level is low and the pins do not touch ink. By
detecting the capacitance, the ink supply motor is controlled to keep the ink level
constant.
If the pins detect an insufficient amount of ink after activating the ink pump motor
for 40 seconds, a "no ink condition" is detected. The add ink indicator on the
operation panel will light.
NOTE:
There is an ink supply mode, which is useful when installing a new drum.
When the “Economy Mode” key is pressed while holding down the “0” key,
the drum turns 40 rotations, to supply ink inside the drum.
The ink roller blades [D] located on both ends of the ink roller are used to scrape
off the built-up ink on the ends of the ink roller.
C231/C237 SM
2-32
Page 79
2.5.6 DETECTI O N OF MASTERS ON THE DRUM
[A]
[B]
DRUM
Detailed
Section
Descriptions
C231D571.WMF
The drum master sensor [B] detects whether a master is on the drum.
When there is a master on the drum, the black patc h [A] is covered and the sensor
detects the light reflected from the master. Printing starts when the start key is
pressed. (If a new original is set, the master ejecting cycle is performed before
making a new master.)
When there is no master on the drum, the black patch [A] is exposed. The black
patch does not reflect light back to the sensor. Because of this, the master eject
process is skipped when a new master is made.
SM C231/C237
2-33
Page 80
PAPER FEED
2.6 PAPER FEED
2.6.1 OVERALL
[B]
[A]
[D]
[C]
C231D543.WMF
The top sheet of the paper on the paper table is first fed by the pick-up roller [A].
Then, it is separated by the paper feed roller [B] and the friction pad [C], and
transported to the registration rollers [D]. The upper and lower registration rollers
transport the sheet to the drum.
The paper feed roller is driven by the main motor, and an independent stepper
motor is used to control the registration roller. The registration roller synchronizes
the paper feed timing with the master on the drum. The registration roller starts
rotating after the paper has come into contact with the rollers and has been
aligned.
C231/C237 SM
2-34
Page 81
2.6.2 PAPER FEED MECHANISM
[B]
[A]
PAPER FEED
[D]
Detailed
Section
Descriptions
[E]
[C]
C231D556.WMF
The pick-up roller [A] and paper feed roller [B] are driven by the main motor [C]
through gears and a timing belt.
During the printing cycle, when the feed start timing sensor [D] is actuated by the
actuator on the drum, the paper feed clutch [E] is energized to transmit the main
motor rotation to the paper feed roller shaft. The top sheet of the paper is
separated from the paper stack by the friction between the roller and the friction
pad (not shown), and is then transported to the registration roller.
A one-way clutch is installed in the paper feed roller so that after the
electromagnetic clutch is de-energized, it does not disturb the paper transportation.
SM C231/C237
2-35
Page 82
PAPER FEED
2.6.3 PAPER FEED/SEPARATION PRESSURE ADJUSTMENT
MECHANISM
[B]
[A]
C231D554.WMF
[E]
[D]
[C]
C231D558.WMF
The paper feed roller pressure can be changed by the operator by changing the
position of the pressure adjustment lever [A]. Normally the lever should be in the
lower position. If the thick paper (heavier than 127.9 g/m
2
or 34 lb) is used or paper
feed jams frequently occur, the lever should be raised to increase the pressure.
An additional fine adjustment can be done by a technician by changing the position
of the feed pressure adjustment plate [B].
If no feed or multi-sheet feed problems still occur, the paper separation pressure
can also be adjusted. (This should be done by a technician.)
By loosening then moving the screw [C]up or down, the spring [D], which applies
pressure to the friction pad block [E], can be increased or decreased.
NOTE:
C231/C237 SM
The default position of the screw [C] is at the lower-most position.
2-36
Page 83
2.6.4 REGISTRATION ROLLER MECHANISM
[B]
[A]
PAPER FEED
Detailed
Section
Descriptions
C231D544.WMF
Registration Roller Drive
The lower registration roller [A] is driven by a stepper motor [B] (the registration
motor). The CPU controls the registration roller start timing to synchronize the
printing paper with the image on the master on the drum.
The stepper motor rotation speed depends on the selected printing speed. By
pressing the image position keys on the operation panel, the registration motor
start timing is changed.
After the printing paper is caught between the drum and the press roller, the
stepper motor stops.
SM C231/C237
2-37
Page 84
PAPER FEED
[
[B]
[C]
[D]
C231D545.WMF
A]
Registration Roller Up/Down Mechanism
After the printing paper is caught between the drum and the press roller, the upper
registration roller is releas ed from the lower registration roller. This is to prevent
interference from the registration rollers while the paper is transported by the drum
and the press roller.
When the hi gh point of the cam [A] on the drum drive gear reach es the cam
follower [B], the shaft [C] rotates clockwise (as seen from the operation side) to
raise the upper registration rolle r [D] f rom the lower registration roller (not shown).
C231/C237 SM
2-38
Page 85
2.6.5 PRINTING PRESSURE MECHANISM
[
[I]
[E]
[A]
[F]
[D]
PAPER FEED
[B]
Detailed
Section
Descriptions
[H]
[C]
[A]
[E]
[G]
I ]
C231D546.WMF
[F]
While the machine is not in the printing cycle, the printing pressure release
solenoids [A] are off and the stoppers [B] lock the brackets [C] to keep the press
roller [D] away from the drum.
When the 1st sheet of paper is fed, the solenoids are e nergized but the brackets
are still locked by the stoppers due to strong tension from the springs [E]. When the
high points of the cams [F] on the front and rear drum flanges reach the cam
followers [G] on both sides of the press roller shaft, a small clearance is made
between the stoppers and the brackets.
There is one solenoid each on the operation side and non-operation side. The two
solenoid plungers are pulled down at the same time releasing the stoppers from
the brackets. Printing pressure is applied by the tension of the springs when the
cam followers are at the high points of the cams.
During the printing cycle, the solenoids stay energized. However, if paper does not
reach the registration sensor [H] at the proper time (when the cam follower is on
the high point of the cam), the solenoids are de-energized to lock the brackets.
The printing pressure is released when the cams push the cam followers down so
that the press roller does not come in contact with the master clamper [I].
After printing is finished, the solenoids are de-energized and the stoppers are
returned by the tension of the springs. Before the drum returns to the home
position, the brackets are locked by the stoppers again when the cams push the
cam followers.
SM C231/C237
2-39
Page 86
PAPER FEED
2.6.6 PAPER TABLE MECHANISM
[B]
[C]
[C]
[B]
[G]
[A]
[F]
[E]
C231D547.WMF
[D]
C231D555.WMF
Table Up and Down Mechanism
An independent dc motor, the paper table motor [A], drives the paper table. When
the motor turns, the pinions [B] turn on the racks [C], lifting or lowering the paper
table.
When the p aper table moves up, t h e top of the paper stack contact s the pick-u p
roller [D], lifting it up. When the paper height sensor [E] is actuated, the paper table
stops.
During a printing run, the sheets of the stack are fed, lowering the pick-up roller
position. When the paper height sensor is de-actuated, the paper table motor starts
turning and raises the paper table until the sensor is actuated again. In this way,
the top of the paper stack is kept in position during printing.
When the tra y lowers , the lower limit position is detected by the lower limit sensor
[F], which is located beside the paper table motor.
Paper End Detection Mechanism
The paper end sensor [G] located under the paper table is used to detect when the
paper stack on the table has run out.
C231/C237 SM
2-40
Page 87
[B]
PAPER FEED
[C]
Detailed
Section
Descriptions
[A]
C231D548.WMF
Paper Table Side Fence Mechanism
The left and right side fences [A] move together due to a rack and pinion
mechanism. There is a lock lever [B] to hold the side fences in position.
NOTE:
The lock lever may be useful if there is no dedicated operator and some of
the operators cannot set the side fences properly, causing paper feed
problems. Advise the operator to use the lock lever once the paper fences
are properly adjusted.
Paper Table Side-to-Side Shift Mechanism
The paper table shifting dial [C] shifts the image on the paper. When the dial is
turned, the whole paper table moves towards the front or the rear of the machine.
SM C231/C237
2-41
Page 88
PAPER FEED
[A]
C231D559.WMF
Side Fence Friction Pads
The two side fence friction pads are included as accessories. These are not
normally used, but if paper multi-feed frequently occurs, the friction pads [A] can be
installed to apply additional stopping pressure to the paper. These are especially
useful when thin paper is used.
The user can install the friction pads if they are using thin paper.
C231/C237 SM
2-42
Page 89
2.7 PAPER DELIVERY
2.7.1 OVERALL
PAPER DELIVERY
[B]
[A]
[C]
C231D549.WMF
The exit pawl [A] and the air knife [B] separate the paper from the drum. The paper
is transported to the delivery table by the delivery unit, which includes rubber belts
and a vacuum fan motor.
The paper exit sensor [C] (a reflective photosensor) is used to detect paper
delivery jams.
Detailed
Section
Descriptions
SM C231/C237
2-43
Page 90
PAPER DELIVERY
2.7.2 PAPER DELIVERY UNIT DRIVE MECHANISM
[A]
[B]
C231D550.WMF
The vacuum fan inside the unit holds the paper against the transport belts [A] to
deliver the paper onto the delivery table. The transport belts are driven by an
independent dc motor (the paper delivery motor [B]).
C231/C237 SM
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Page 91
2.7.3 PAPER SEPARATION FROM DRUM
[B]
[A]
PAPER DELIVERY
[B]
Detailed
Section
Descriptions
C231D551.WMF
[C]
The air from the air knife nozzle [A] separates the paper from the drum.
The exit pawl [B] prevents the paper from being transported upwards and being
wrapped around the drum, if the air does not separate the paper properly.
The air knife fan motor [C] starts blowing air when either the print start key is
pressed or the master cutting cycle is finished. The paper passes under the exit
pawl and is delivered onto the delivery table. The motor air knife stops after the last
sheet of paper is fed out.
SM C231/C237
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Page 92
PAPER DELIVERY
[
2.7.4 EXIT PAWL DRIVE MECHANISM
During printing, the distance
between the exit pawl [A] and
the drum is very small to
prevent paper wrap jams.
However, when the master
clamper [B] approaches the exit
pawl (as the drum turns), the
pawl has to be moved away
from the drum to prevent it from
being damaged by the master
clamper. This is controlled b y
the front drum flange [C], which
is cam-shaped, and the cam
follower [E] on the exit pawl
shaft.
When the cam follower is not
pushed away by the drum
flange, the exit pawl is
positioned close to the drum
surface, by the tension of
spring [G].
[A]
[E]
[B]
[C]
[D]
As the master clamper
approaches the exit pawl, the
high point of the drum flange
cam [C] moves into contact
with the cam follower [E]
[G]
pushing it down. This moves
the cam follower arm [F]
downwards. The pawl shaft
turns clockwise to move the pawl away from the drum.
When printing finishes and the
printing pressure is released, the
cam follower arm [F] is engaged by
the printing pressure release arm
[D] and held in the lower position.
Therefore, after printing finishes,
the cam follower is out of contact
with the cam, and the exit pawl
moves away from the drum to its
normal position.
[F]
C231D561.WMF
[D]
C231D562.WMF
C231/C237 SM
2-46
F]
Page 93
ERROR DETECTION
2.8 ERROR DETECTION
2.8.1 ORIGINAL JAM DETECTION
The jam indicator lights if any one of the following conditions occur.
Jam Condition Description
Non-feed
Misfeed 1
Misfeed 2
2.8.2 MASTER EJECT JAM DETECTION
The scan line sensor does not switch on within
5 seconds after the ADF motor starts.
The scan line sensor does not turn off after turning on even when the
trial print is made (when the printing pressure sensor is actuated).
When the final page of the document has been fed out of the scanner,
or when a jammed document has been removed, the ADF motor
reverses. The message is displayed if the document sensor stays on at
this time.
Detailed
Section
Descriptions
[A]
[B]
C231D553.WMF
The master eject jams are detected by the master eject sensor [A]. The jam
indicator will light if any of the following conditions occurs:
1) If the master eject sensor is actuated when the main switch is turned on.
2) If the master eject sensor is not actuated within 0.3 seconds after the drum
started turning to feed the master into the master eject box.
3) If the master eject sensor is not actuated when the drum makes a half turn
and passes the 2nd feed timing sensor [B]. This happens when the leading
edge of the picked up master is pulled back to the drum and the master
remains on the drum. (The jam indicator lights after the drum returns to the
home position.)
4) If the master eject sensor is actuated when the pressure plate is returned to
the home position. This happens when the trailing edge of the master sticks
on the pressure plate and is pulled back to the master eject rollers.
SM C231/C237
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Page 94
ERROR DETECTION
2.8.3 MASTER FEED JAM DETECTION
[B]
[D]
[A]
C231D563.WMF
There is no jam sensor in the master feed path. Master feed jams are detected by
the drum master sensor [A], which detects the presence of the master on the drum.
When the dru m returns to the home position (i.e. the master eject position) after
master making, if the drum master sensor [A] does not detect a master on the
drum, the jam indicator on the operation panel will light. (The master eject position
sensor [B] is used to identify when the drum is at the home position.)
C231/C237 SM
2-48
Page 95
2.8.4 PAPER FEED JAM DETECTION
ERROR DETECTION
[B]
Detailed
Section
Descriptions
[A]
[C]
[D]
[E]
C231D560.WMF
Paper jams are detected by the registration sensor [D] and the exit sensor [E]. Jam
detection timing is determined by the drum position sensors and the main motor
encoder (not shown). The 2nd feed timing sensor [A] and the paper exit timing
sensor [B] are used as the drum position sensors.
The timing chart on the next page shows the jam detection timing.
SM C231/C237
2-49
Page 96
ERROR DETECTION
Feed Start
Timing Sensor
2nd Feed
Timing Sensor
Paper Exit
Timing Sensor
Registration
Sensor
Exit Sensor
N
a) ON Check
b) OFF Check
t
c) Feed or Wrapping Jam
c) ON Check
C231D570.WMF
a) When the CPU counts a certain number of main motor encoder pulses
(N) after the feed start timing sensor is actuated, if the registration sensor
does not detect the paper, the jam indicator lights.
b) When the paper exit timing sensor is actuated, if the exit sensor remains
activated, the jam indicator lights.
c) When a certain time (t) (this time depends on the drum speed) has
passed after the paper exit timing sensor is actuated, if the exit sensor is
not activated, the machine detects a paper jam. If this jam condition is
detected, the CPU will stop the next paper from being fed. When the 2nd
feed timing sensor is actuated:
1. If the registration sensor is activated, a registration failure is
detected.
2. If the registration sensor is not activated, a paper wrap jam is
detected.
C231/C237 SM
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Page 97
INSTALLATION
Page 98
Page 99
INSTALLATION REQUIREMENTS
3. INSTALLATION
3.1 INSTALLATION REQUIREMENTS
Carefully select the installation location because environmental conditions greatly
affect machine performance.
3.1.1 OPTIMUM ENVIRONMENTAL CONDITION
1. Temperature 10 to 30°C (50 to 86°F)
2. Humidity 20 to 90 % RH 20 to70 % RH (ADF)
3. Install the machine on a strong and level base. The machine must be level
within 5 mm (0.2”) both front to rear and left to right.
Installation
3.1.2 ENVIRONMENTS TO AVOID
1. Locations exposed to direct sunlight or strong light (more than 1,500 lux).
2. Dusty areas.
3. Areas containing corrosive gases.
4. Locations directly exposed to cool air from an air conditioner or reflected heat
from a space heater. (Sudden temperature changes from low to high or vice
versa may cause condensation within the machine.)
3.1.3 POWER CONNECTION
1. Securely connect the power cord to a power source.
2. Make sure that the wall outlet is near the machine and easily accessible.
3. Make sure the plug is firmly inserted in the outlet.
4. Voltage must not fluctuate more than 10%.
5. Avoid multi-wiring.
6. Do not pinch the power cord.
SM C231/C237
3-1
Page 100
INSTALLATION REQUIREMENTS
M
M
6
(
P
F
T
3.1.4 ACCESS TO MACHINE:
Place the machine near a power source, providing clearance as shown below.
ore than 20 cm (7.9")
Paper
Delivery
Table
More than
60 cm
(23.7”)
119 cm (46.9")
aper
eed
able
ore than
0 cm
23.7”)
59 cm
(23.3")
More than
60 cm
(23.7”)
C231I510.WMF
C231/C237 SM
3-2
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