Gestetner A294, A295 Service Manual

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A294/A295

SERVICE MANUAL

000902MIU

RICOH GROUP COMPANIES

CÓPIA NÃO CONTROLADA

A294/A295

SERVICE MANUAL

RICOH GROUP COMPANIES

CÓPIA NÃO CONTROLADA

A294/A295

SERVICE MANUAL

000902MIU

CÓPIA NÃO CONTROLADA

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NO PART OF THIS DOCUMENT MAY BE REPRODUCED IN ANY

FASHION AND DISTRIBUTED WITHOUT THE PRIOR

PERMISSION OF RICOH CORPORATION.

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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.



CÓPIA NÃO CONTROLADA

The Service Manual contains information regarding service techniques, procedures, processes and spare parts of office equipment distributed by Ricoh Corporation. User s of this manual should be either service trained or certified by successfully completing a Ricoh T echnical Training Program.

Untrained and uncertified users utilizing information contained in this service manual to repair or modify Ricoh equipment risk personal injury, damage to property or loss of warranty protection.

Ricoh Corporation

WARNING

CÓPIA NÃO CONTROLADA

LEGEND

PRODUCT CODE COMPANY

GESTETNER RICOH SAVIN

A294-I

3285 Aficio 850 2085DP

A295-I

32105 Aficio1050 2105DP

A294-II

8502 Aficio 1085 2585

A295-II

10502 Aficio 1105 25105

DOCUMENTATION HISTORY

REV. NO. DATE COMMENTS

* 1/2000 Original Printing

1 7/2000 A295 Addition 29/2001

A294-II/A295-II Addition

CÓPIA NÃO CONTROLADA

SM i A294A295

TABLE OF CONTENTS

OVERALL INFORMATION

1. OVERALL MACHINE INFORMATION........................................ 1-1

1.1 SPECIFICATIONS.....................................................................................1-1

1.1.1 COPIER ENGINE.............................................................................1-1

1.1.2 ADF ..................................................................................................1-4

1.2 MACHINE CONFIGURATION...................................................................1-5

1.3 COMPONENT LAYOUT............................................................................1-6

1.3.1 COPIER ENGINE.............................................................................1-6

1.3.2 ADF ..................................................................................................1-7

1.4 PAPER PATH............................................................................................1-8

1.5 COPY PROCESS......................................................................................1-9

1.6 DRIVE LAYOUT......................................................................................1-11

1.6.1 COPIER ENGINE...........................................................................1-11

1.6.2 ADF ................................................................................................1-12

1.7 ELECTRICAL COMPONENT DESCRIPTIONS......................................1-13

1.7.1 COPIER ENGINE...........................................................................1-13

1.7.2 ADF ................................................................................................1-19

DETAILED DESCRIPTIONS

2. DETAILED SECTION DESCRIPTIONS ...................................... 2-1

2.1 DOCUMENT FEEDER..............................................................................2-1

2.1.1 PICK-UP ROLLER RELEASE..........................................................2-1

2.1.2 BOTTOM PLATE LIFT......................................................................2-2

2.1.3 PICK-UP AND SEPARATION...........................................................2-3

2.1.4 ORIGINAL FEED..............................................................................2-4

2.1.5 ORIGINAL SIZE DETECTION..........................................................2-5

2.1.6 ORIGINAL TRANSPORT .................................................................2-6

2.1.7 ORIGINAL SKEW CORRECTION....................................................2-7

2.1.8 ORIGINAL INVERSION AND FEED-OUT........................................2-8

2.1.9 JAM CONDITIONS.........................................................................2-12

2.2 SCANNING..............................................................................................2-13

2.2.1 OVERVIEW....................................................................................2-13

2.2.2 SCANNER DRIVE..........................................................................2-14

2.2.3 ORIGINAL SIZE DETECTION IN BOOK MODE............................2-15

2.3 IMAGE PROCESSING............................................................................2-17

2.3.1 OVERVIEW....................................................................................2-17

2.3.2 SBU................................................................................................2-18

2.3.3 AUTO IMAGE DENSITY (ADS)......................................................2-19

2.3.4 IMAGE PROCESSING STEPS AND RELATED SP MODE...........2-20

2.3.5 AUTO SHADING ............................................................................2-26

2.3.6 BACKGROUND ERASE.................................................................2-27

2.3.7 INDEPENDENT DOT ERASE........................................................2-28

Rev. 10/2000

CÓPIA NÃO CONTROLADA

A294/A295 ii SM

2.3.8 FILTERING, MAIN SCAN MAGNIFICATION/REDUCTION ...........2-29

2.3.9 GAMMA (γ) CORRECTION............................................................2-31

2.3.10 GRADATION PROCESSING........................................................2-31

2.3.11 LINE WIDTH CORRECTION........................................................2-32

2.4 LASER EXPOSURE................................................................................2-33

2.4.1 OVERVIEW....................................................................................2-33

2.4.2 OPTICAL PATH..............................................................................2-34

2.4.3 AUTO POWER CONTROL (APC)..................................................2-35

2.4.4 FOUR BEAM LASER WRITING.....................................................2-36

2.4.5 LD SAFETY SWITCHES................................................................2-37

2.5 DRUM UNIT ............................................................................................2-38

2.5.1 PROCESS CONTROL....................................................................2-38

2.5.2 TONER DENSITY CONTROL........................................................2-43

2.5.3 DRUM UNIT COMPONENTS.........................................................2-46

2.5.4 DRIVE............................................................................................. 2-47

2.5.5 DRUM CHARGE.............................................................................2-48

2.5.6 DRUM CLEANING..........................................................................2-50

2.5.7 OTHERS.........................................................................................2-53

2.6 DEVELOPMENT .....................................................................................2-56

2.6.1 OVERVIEW....................................................................................2-56

2.6.2 DEVELOPMENT MECHANISM......................................................2-57

2.6.3 DRIVE............................................................................................. 2-58

2.6.4 CROSSMIXING..............................................................................2-59

2.6.5 DEVELOPMENT BIAS ...................................................................2-60

2.7 TONER SUPPLY AND RECYCLING.......................................................2-61

2.7.1 TONER BANK................................................................................2-61

2.7.2 SUPPLYING TONER TO THE DEVELOPMENT UNIT..................2-65

2.7.3 TONER HOPPER...........................................................................2-66

2.7.4 TONER RECYCLING AND WASTE TONER COLLECTION..........2-68

2.8 PAPER FEED..........................................................................................2-71

2.8.1 OVERVIEW....................................................................................2-71

2.8.2 DRIVE............................................................................................. 2-72

2.8.3 PAPER LIFT – TRAYS 2 & 3..........................................................2-73

2.8.4 PICK-UP AND FEED – TRAYS 1 TO 3..........................................2-75

2.8.5 REMAINING PAPER/

PAPER END DETECTION – TRAYS 2 & 3....................................2-79

2.8.6 PAPER SIZE DETECTION – TRAYS 2 & 3....................................2-80

2.8.7 TRAY LOCK – TRAYS 2 & 3..........................................................2-81

2.8.8 TANDEM FEED – TRAY 1 .............................................................2-82

2.8.9 VERTICAL TRANSPORT...............................................................2-89

2.8.10 PAPER REGISTRATION..............................................................2-90

2.9 IMAGE TRANSFER AND PAPER SEPARATION...................................2-93

2.9.1 OVERVIEW....................................................................................2-93

2.9.2 IMAGE TRANSFER AND PAPER SEPARATION..........................2-94

2.9.3 TRANSFER BELT UNIT LIFT.........................................................2-96

2.9.4 PAPER TRANSPORTATION AND BELT DRIVE...........................2-97

2.9.5 TRANSFER BELT CLEANING.......................................................2-98

2.9.6 TONER COLLECTION...................................................................2-99

2.9.7 TRANSFER ANTI-CONDENSATION HEATER............................2-100

Rev. 10/2000

CÓPIA NÃO CONTROLADA

SM iii A294A295

2.10 FUSING...............................................................................................2-101

2.10.1 OVERVIEW................................................................................2-101

2.10.2 FUSING ENTRANCE GUIDE.....................................................2-102

2.10.3 FUSING UNIT DRIVE.................................................................2-103

2.10.4 FUSING LAMP CONTROL.........................................................2-104

2.10.5 OIL SUPPLY AND CLEANING...................................................2-105

2.10.6 PAPER COOLING......................................................................2-106

2.10.7 FUSING PRESSURE .................................................................2-107

2.10.8 HOT ROLLER STRIPPER RELEASE........................................2-108

2.11 PAPER EXIT/DUPLEX........................................................................2-109

2.11.1 OVERVIEW................................................................................2-109

2.11.2 PAPER EXIT MECHANISM........................................................2-110

2.11.3 DUPLEX DRIVE MECHANISM...................................................2-111

2.11.4 INVERTER..................................................................................2-112

2.11.5 DUPLEX TRAY FEED MECHANISM .........................................2-114

2.11.6 BASIC DUPLEX FEED OPERATION.........................................2-115

2.12 ENERGY SAVER MODES..................................................................2-119

2.12.1 OVERVIEW................................................................................2-119

2.12.2 ENERGY SAVER (PANEL OFF) MODE ....................................2-120

2.12.3 LOW POWER MODE .................................................................2-121

2.12.4 OFF MODE.................................................................................2-122

2.12.5 SUMMARY .................................................................................2-124

2.13 OTHERS..............................................................................................2-125

2.13.1 OPERATION UNIT.....................................................................2-125

2.13.2 DOOR SAFETY SWITCH LOCK TOOLS...................................2-126

2.13.3 HDD CONTROL .........................................................................2-127

2.13.4 DATA PATH THROUGH THE INTERFACE BOARD.................2-129

INSTALLATION

3. INSTALLATION PROCEDURE................................................... 3-1

3.1 INSTALLATION REQUIREMENTS...........................................................3-1

3.1.1 ENVIRONMENT...............................................................................3-1

3.1.2 MACHINE LEVEL.............................................................................3-1

3.1.3 MINIMUM SPACE REQUIREMENTS...............................................3-2

3.1.4 POWER REQUIREMENTS..............................................................3-2

3.2 COPIER (A294).........................................................................................3-3

3.2.1 ACCESSORY CHECK......................................................................3-3

3.2.2 INSTALLATION PROCEDURE........................................................3-5

3.3 FINISHER INSTALLATION (B302)..........................................................3-13

3.3.1 ACCESSORY CHECK....................................................................3-13

3.3.2 INSTALLATION PROCEDURE......................................................3-14

3.4 LCT INSTALLATION (B303)....................................................................3-17

3.4.1 ACCESSORY CHECK....................................................................3-17

3.4.2 INSTALLATION PROCEDURE......................................................3-18

3.4.3 INSTALLATION PROCEDURE FOR THE TRAY HEATER KIT..3-19B

3.5 PUNCH UNIT INSTALLATION (A812)....................................................3-20

3.5.1 ACCESSORY CHECK....................................................................3-20

3.5.2 PUNCH UNIT INSTALLATION.......................................................3-21

Rev. 10/2000

CÓPIA NÃO CONTROLADA

A294/A295 iv SM

3.6 A3/DLT TRAY (B331)..............................................................................3-24

3.6.1 ACCESSORY CHECK....................................................................3-24

3.6.2 INSTALLATION PROCEDURE......................................................3-25

3.7 KEY COUNTER INSTALLATION............................................................3-28

3.8 INTERFACE BOARD

(CD-RW/TANDEM COPY KIT/PRINTER CONTROLLER)......................3-31

3.8.1 INSTALLATION PROCEDURE......................................................3-31

3.8.2 INSTALLATION NOTES FOR CD-R/RW .......................................3-32

3.9 TRANSPORTATION REMARKS.............................................................3-32

3.9.1 TONER TRANSPORT TUBE CLEANING ......................................3-32

SERVICE TABLES

4. SERVICE TABLES...................................................................... 4-1

4.1 GENERAL CAUTIONS..............................................................................4-1

4.1.1 DRUM............................................................................................... 4-1

4.1.2 DRUM UNIT......................................................................................4-1

4.1.3 TRANSFER BELT UNIT...................................................................4-2

4.1.4 SCANNER UNIT...............................................................................4-2

4.1.5 LASER UNIT.....................................................................................4-2

4.1.6 CHARGE CORONA..........................................................................4-3

4.1.7 DEVELOPMENT...............................................................................4-3

4.1.8 CLEANING.......................................................................................4-4

4.1.9 FUSING UNIT...................................................................................4-4

4.1.10 PAPER FEED.................................................................................4-4

4.1.11 USED TONER................................................................................4-4

4.2 SERVICE PROGRAM MODE....................................................................4-5

4.2.1 SERVICE PROGRAM MODE OPERATION.....................................4-5

4.2.2 SERVICE PROGRAM MODE TABLES..........................................4-10

4.2.3 TEST PATTERN PRINTING (SP2-902).........................................4-59

4.2.4 INPUT CHECK ...............................................................................4-60

4.2.5 OUTPUT CHECK ...........................................................................4-68

4.2.6 SYSTEM PARAMETER AND DATA LISTS (SMC LISTS) .............4-70

4.2.7 MEMORY ALL CLEAR (SP5-801)..................................................4-70

4.2.8 SOFTWARE RESET ......................................................................4-71

4.2.9 SYSTEM SETTING AND

COPY SETTING (UP MODE) RESET............................................4-71

4.3 PM COUNTER ........................................................................................4-72

4.3.1 PM COUNTER ACCESS PROCEDURE........................................4-72

4.4 PROGRAM DOWNLOAD........................................................................4-78

4.5 NVRAM DATA DOWNLOAD...................................................................4-80

4.6 LANGUAGE DATA DOWNLOAD............................................................4-81

4.7 STAMP DATA DOWNLOAD....................................................................4-81

4.8 USER PROGRAM MODE .......................................................................4-82

4.8.1 HOW TO ENTER AND EXIT UP MODE.........................................4-82

4.8.2 UP MODE TABLE...........................................................................4-82

4.8.3 IMAGE QUALITY SETTING BY UP MODE....................................4-85

4.8.4 LEDS..............................................................................................4-91

Rev. 9/2001

CÓPIA NÃO CONTROLADA

SM v A294A295

4.9 TEST POINTS/DIP SWITCHES/LEDS....................................................4-92

4.9.1 DIP SWITCHES..............................................................................4-92

4.9.2 TEST POINTS................................................................................4-93

4.9.3 FUSES............................................................................................4-93

4.9.4 VARIABLE RESISTORS ................................................................4-93

4.10 SPECIAL TOOLS AND LUBRICANTS..................................................4-94

4.10.1 SPECIAL TOOLS .........................................................................4-94

4.10.2 LUBRICANTS...............................................................................4-94

PREVENTIVE MAINTENANCE

5. PREVENTIVE MAINTENANCE SCHEDULE .............................. 5-1

5.1 PM PARTS................................................................................................5-1

REPLACEMENT AND ADJUSTMENT

6. REPLACEMENT AND ADJUSTMENT........................................ 6-1

6.1 EXTERIOR................................................................................................6-1

6.1.1 FRONT.............................................................................................6-1

6.1.2 RIGHT ..............................................................................................6-2

6.1.3 LEFT.................................................................................................6-3

6.1.4 REAR................................................................................................6-4

6.2 DOCUMENT FEEDER..............................................................................6-5

6.2.1 COVER REMOVAL ..........................................................................6-5

6.2.2 FEED UNIT REMOVAL AND

SEPARATION ROLLER REPLACEMENT .......................................6-7

6.2.3 FEED BELT REPLACEMENT..........................................................6-8

6.2.4 PICK-UP ROLLER REPLACEMENT................................................6-9

6.2.5 SENSOR REPLACEMENT.............................................................6-10

6.2.6 TRANSPORT BELT REPLACEMENT............................................6-14

6.2.7 MOTOR REPLACEMENT ..............................................................6-15

6.2.8 FEED-IN CLUTCH REPLACEMENT..............................................6-17

6.3 SCANNER UNIT......................................................................................6-18

6.3.1 EXPOSURE GLASS.......................................................................6-18

6.3.2 LENS BLOCK.................................................................................6-19

6.3.3 ORIGINAL SIZE SENSORS...........................................................6-20

6.3.4 EXPOSURE LAMP.........................................................................6-21

6.3.5 LAMP REGULATOR.......................................................................6-22

6.3.6 OPTICS DUST FILTER..................................................................6-23

6.3.7 SCANNER H.P. SENSOR..............................................................6-24

6.3.8 SCANNER MOTOR........................................................................6-25

6.3.9 SCANNER DRIVE WIRES .............................................................6-26

6.4 LASER UNIT ...........................................................................................6-29

6.4.1 CAUTION DECAL LOCATIONS.....................................................6-29

6.4.2 LDB AND LD FILTER REPLACEMENT .........................................6-30

6.4.3 POLYGON MIRROR MOTOR REPLACEMENT............................6-31

6.4.4 LASER SYNCHRONIZATION DETECTOR REPLACEMENT........6-32

Rev. 9/2001

CÓPIA NÃO CONTROLADA

A294/A295 vi SM

6.5 DRUM UNIT ............................................................................................6-33

6.5.1 DRUM UNIT REMOVAL AND DRUM REPLACEMENT .................6-33

6.5.2 QUENCHING LAMP REPLACEMENT ...........................................6-34

6.5.3 GRID PLATE/CHARGE CORONA WIRE/

WIRE CLEANER REPLACEMENT.................................................6-35

6.5.4 DRUM POTENTIAL SENSOR REPLACEMENT ............................6-37

6.5.5 CLEANING BLADE/ID SENSOR REPLACEMENT ........................6-38

6.5.6 CLEANING BRUSH REPLACEMENT............................................6-39

6.5.7 PICK-OFF PAWL REPLACEMENT................................................6-40

6.5.8 DRUM FILTER REPLACEMENT....................................................6-41

6.5.9 OPC DRUM CHANGE....................................................................6-41

6.6 DEVELOPMENT AND TONER SUPPLY ................................................6-42

6.6.1 DEVELOPMENT UNIT REMOVAL.................................................6-42

6.6.2 DEVELOPER REPLACEMENT......................................................6-43

6.6.3 DEVELOPMENT AND AIR DUST FILTER REPLACEMENT .........6-45

6.6.4 DEVELOPMENT ENTRANCE, FRONT, & REAR SIDE SEALS ...6-46

6.6.5 TONER DENSITY SENSOR REPLACEMENT...............................6-47

6.6.6 TONER HOPPER SENSOR REPLACEMENT ...............................6-48

6.6.7 DEVELOPMENT MOTOR REPLACEMENT...................................6-49

6.6.8 DEVELOPMENT ROLLER SHAFT CLEANING .............................6-50

6.7 TRANSFER BELT UNIT..........................................................................6-51

6.7.1 TRANSFER BELT UNIT REMOVAL/INSTALLATION ....................6-51

6.7.2 TRANSFER BELT REPLACEMENT...............................................6-53

6.7.3 TRANSFER BELT CLEANING BLADE REPLACEMTNT...............6-55

6.7.4 TRANSFER BELT BIAS BRUSH REPLACEMENT ........................6-56

6.8 PAPER FEED..........................................................................................6-57

6.8.1 PAPER TRAY REMOVAL ..............................................................6-57

6.8.2 PAPER FEED ROLLER REPLACEMENT......................................6-60

6.8.3 PAPER FEED AND VERTICAL TRANSPORT CLUTCH, AND TRAY LIFT, PAPER FEED, AND

PAPER END SENSOR REMOVAL ...............................................6-61

6.8.4 REAR FENCE RETURN SENSOR REPLACEMENT.....................6-64

6.8.5 REAR FENCE HP SENSOR REPLACEMENT...............................6-65

6.8.6 RIGHT 1ST TRAY PAPER SENSOR REPLACMENT....................6-66

6.8.7 BOTTOM PLATE LIFT WIRE REPLACEMENT..............................6-67

6.8.8 PAPER DUST REMOVER CLEANING ..........................................6-69

6.8.9 REGISTRATION SENSOR CLEANING .........................................6-70

6.8.10 UNIVERSAL TRAY SIZE SWITCH REPLACEMENT ...................6-71

6.8.11 1ST TRAY LIFT MOTOR REMOVAL ...........................................6-72

6.8.12 LIFT MOTOR REMOVAL (2ND & 3RD TRAYS)...........................6-73

6.8.13 PAPER FEED MOTOR REMOVAL ..............................................6-74

6.8.14 RELAY MOTOR, UPPER RELAY CLUTCH,

LCT RELAY CLUTCH REMOVAL................................................6-75

6.8.15 REGISTRATION MOTOR REMOVAL..........................................6-76

6.8.16 COPIER FEED UNIT/DEVELOPMENT FAN MOTOR

REMOVAL....................................................................................6-77

6.8.17 LCT RELAY AND RELAY SENSOR REMOVAL ..........................6-78

6.8.18 TANDEM FEED TRAY PAPER SIZE CHANGE ...........................6-79

6.8.19 MECHANICAL SIDE REGISTRATION ADJUSTMENT ................6-82

Rev. 05/2004

CÓPIA NÃO CONTROLADA

SM vii A294A295

6.9 FUSING UNIT..........................................................................................6-83

6.9.1 OIL SUPPLY & CLEANING WEB UNIT REMOVAL.......................6-83

6.9.2 HOT ROLLER UNIT REMOVAL AND

PRESSURE ROLLER REPLACEMENT.........................................6-84

6.9.3 HOT ROLLER REPLACEMENT.....................................................6-86

6.9.4 OIL SUPPLY & CLEANING WEB REPLACEMENT.......................6-88

6.9.5 WEB CLEANING ROLLER REPLACEMENT.................................6-90

6.9.6 HOT ROLLER STRIPPER REPLACEMENT..................................6-91

6.9.7 PRESSURE ROLLER STRIPPER REPLACEMENT......................6-92

6.9.8 PRESSURE ROLLER CLEANING ROLLER REPLACEMENT ......6-93

6.9.9 FUSING AND EXIT UNIT REMOVAL.............................................6-94

6.9.10 FUSING PRESSURE ADJUSTMENT ..........................................6-95

6.10 PAPER EXIT/DUPLEX UNIT.................................................................6-96

6.10.1 EXIT SENSOR REPLACEMENT..................................................6-96

6.10.2 DUPLEX UNIT REMOVAL ...........................................................6-97

6.10.3 DUPLEX UNIT INNER COVER REMOVAL..................................6-98

6.10.4 JOGGER MOTOR REPLACEMENT............................................6-99

6.10.5 DUPLEX UNIT CLUTCH REPLACEMENT.................................6-100

6.10.6 DUPLEX ENTRANCE SENSOR REPLACEMENT.....................6-101

6.10.7 DUPLEX TRANSPORT SENSORS 2 & 3 ..................................6-102

6.10.8 DUPLEX TRANSPORT SENSOR 1/

DUPLEX INVERTER SENSOR..................................................6-103

6.11 TONER BANK.....................................................................................6-104

6.11.1 WASTE TONER BOTTLE REMOVAL........................................6-104

6.11.2 TONER BANK UNIT REMOVAL.................................................6-105

6.11.3 TONER SUPPLY MOTOR AND

TONER SUPPLY MOTOR SENSOR REMOVAL.......................6-108

6.11.4 ACCESS TO INSIDE THE TONER BANK..................................6-109

6.12 BOARDS AND OTHER ITEMS ...........................................................6-110

6.12.1 SICU BOARD.............................................................................6-110

6.12.2 HARD DISK DRIVE....................................................................6-111

6.12.3 BCU BOARD..............................................................................6-112

6.12.4 I/O BOARD.................................................................................6-113

6.12.5 PSU............................................................................................6-114

6.12.6 CHARGE/GRID/BIAS POWER PACK........................................6-115

6.12.7 FUSING/DUPLEX MOTOR REPLACEMENT.............................6-116

6.12.8 DRUM MOTOR REPLACEMENT...............................................6-117

6.13 COPY IMAGE ADJUSTMENT: PRINTING/SCANNING...................... 6-118

6.13.1 PRINTING...................................................................................6-118

6.13.2 PARALLELOGRAM IMAGE ADJUSTMENT ..............................6-121

6.13.3 SCANNING.................................................................................6-123

6.13.4 ADF IMAGE ADJUSTMENT.......................................................6-124

6.14 TOUCH SCREEN CALIBRATION.......................................................6-125

Rev. 2/2000

CÓPIA NÃO CONTROLADA

A294/A295 viii SM

TROUBLESHOOTING

7. TROUBLESHOOTING ................................................................ 7-1

7.1 SERVICE CALL CONDITIONS .................................................................7-1

7.1.1 SUMMARY.......................................................................................7-1

7.1.2 SC CODE DESCRIPTIONS .............................................................7-2

7.2 ELECTRICAL COMPONENT DEFECTS.................................................7-37

7.2.1 SENSORS......................................................................................7-37

7.2.2 SWITCHES.....................................................................................7-41

7.3 BLOWN FUSE CONDITIONS .................................................................7-42

7.4 FIRMWARE HISTORY............................................................................7-43

7.4.1 A294 / A295 FIRMWARE MODIFICATION HISTORY....................7-43

3,000-SHEET FINISHER B302

1. OVERALL MACHINE INFORMATION........................................ 8-1

1.1 SPECIFICATIONS.....................................................................................8-1

1.2 MECHANICAL COMPONENT LAYOUT....................................................8-3

1.3 ELECTRICAL COMPONENT DESCRIPTION...........................................8-4

1.4 DRIVE LAYOUT........................................................................................8-6

2. DETAILED DESCRIPTIONS ....................................................... 8-7

2.1 TRAY AND STAPLER JUNCTION GATE.................................................8-7

2.2 PAPER PRE-STACKING...........................................................................8-8

2.3 JOGGER UNIT PAPER POSITIONING.....................................................8-9

2.4 STAPLER UNIT MOVEMENT.................................................................8-10

2.5 STAPLER................................................................................................8-12

2.6 FEED-OUT..............................................................................................8-14

2.7 SHIFT TRAY UP/DOWN MOVEMENT....................................................8-15

2.8 SHIFT TRAY SIDE-TO-SIDE MOVEMENT.............................................8-16

2.9 PUNCH UNIT DRIVE ..............................................................................8-17

2.10 PUNCH WASTE COLLECTION............................................................8-18

2.11 JAM CONDITIONS................................................................................8-19

3. SERVICE TABLES.................................................................... 8-20

3.1 DIP SWITCHES.......................................................................................8-20

3.2 TEST POINTS.........................................................................................8-20

3.3 FUSES.....................................................................................................8-20

4. REPLACEMENT AND ADJUSTMENT...................................... 8-21

4.1 COVER REPLACEMENT........................................................................8-21

4.2 POSITIONING ROLLER REPLACEMENT..............................................8-24

4.3 ALIGNMENT BRUSH ROLLER REPLACEMENT...................................8-25

4.4 SENSOR REPLACEMENT......................................................................8-26

4.4.1 STACK HEIGHT 1, 2 AND EXIT GUIDE OPEN SENSOR.............8-26

4.4.2 UPPER TRAY PAPER LIMIT AND EXIT SENSOR........................8-27

4.4.3 SHIFT TRAY EXIT SENSOR..........................................................8-28

Rev. 9/2001

CÓPIA NÃO CONTROLADA

SM ix A294A295

4.4.4 ENTRANCE AND

STAPLER TRAY ENTRANCE SENSORS .....................................8-29

4.4.5 PRE-STACK STOPPER SENSOR.................................................8-30

4.4.6 STAPLE WASTE HOPPER SENSOR............................................8-31

4.4.7 STAPLER ROTATION HP AND

STAPLER RETURN SENSORS.....................................................8-32

4.5 STAPLER REMOVAL..............................................................................8-33

4.6 PUNCH POSITION ADJUSTMENT.........................................................8-34

4.7 ROM HISTORY.......................................................................................8-35

4.7.1 FIRMWARE MODIFICATION HISTORY........................................8-35

LARGE CAPACITY TRAY B303

1. OVERALL MACHINE INFORMATION........................................ 9-1

1.1 SPECIFICATIONS.....................................................................................9-1

1.2 MECHANICAL COMPONENT LAYOUT....................................................9-2

1.3 ELECTRICAL COMPONENT DESCRIPTIONS........................................9-3

1.4 DRIVE LAYOUT........................................................................................9-5

2. DETAILED DESCRIPTIONS ....................................................... 9-6

2.1 PAPER FEED............................................................................................9-6

2.2 PICK-UP AND FEED.................................................................................9-7

2.2.1 OVERVIEW......................................................................................9-7

2.2.2 PICK-UP AND FEED........................................................................9-8

2.2.3 SEPARATION ROLLER RELEASE..................................................9-9

2.3 PAPER LIFT............................................................................................9-10

2.3.1 TRAY DETECTION ........................................................................9-10

2.3.2 LIFT MECHANISM .........................................................................9-10

2.3.3 LIFT SENSOR................................................................................9-11

2.4 PAPER SIZE DETECTION......................................................................9-12

2.5 PAPER END DETECTION......................................................................9-13

3. REPLACEMENT AND ADJUSTMENT...................................... 9-14

3.1 EXTERIOR COVER REMOVAL..............................................................9-14

3.2 INNER COVER REMOVAL.....................................................................9-15

3.3 PAPER FEED ROLLER REPLACEMENT............................................... 9-16

3.4 LCT MOTOR REPLACEMENT................................................................9-17

3.5 RELAY SENSOR REPLACEMENT.........................................................9-18

3.6 PAPER HEIGHT SENSOR AND

PAPER SIZE SWITCH REPLACEMENT.................................................9-19

3.7 MAIN DRIVE BELT REPLACEMENT......................................................9-20

3.8 SIDE REGISTRATION ADJUSTMENT...................................................9-21

Rev. 8/2000

CÓPIA NÃO CONTROLADA

A294/A295 x SM

A3/DLT TRAY KIT B331

1. OVERALL MACHINE INFORMATION...................................... 10-1

1.1 SPECIFICATIONS...................................................................................10-1

2. DETAILED DESCRIPTIONS ..................................................... 10-2

2.1 SECTIONAL DESCRIPTION...................................................................10-2

3. REPLACEMENT AND ADJUSTMENT...................................... 10-3

3.1 BOTTOM PLATE LIFT WIRE REPLACEMENT ......................................10-3

DIFFERENCES FROM THE A294 I / A295 I MODELS

1 DETAILED SECTION DESCRIPTIONS ..................................... 11-1

1.1 TONER AND DEVELOPER.....................................................................11-1

1.2 NEWLY ADDED: DEVELOPMENT SUCTION MOTOR AND

SUCKED TONER COLLECTION BOTTLE.............................................11-1

1.3 DEVELOPMENT UNIT............................................................................11-2

1.4 TONER BANK UNIT................................................................................11-3

1.5 CLEANING UNIT.....................................................................................11-3

1.6 FUSING UNIT..........................................................................................11-4

1.7 NEW ADDITIONS TO TRANSFER CURRENT CONTROL.....................11-5

1.8 CHARGE CORONA UNIT.......................................................................11-6

1.9 ELECTRICAL COMPONENTS................................................................11-6

1.10 SOFTWARE..........................................................................................11-8

2 SERVICE TABLES..................................................................... 11-9

2.1 SERVICE PROGRAM MODE..................................................................11-9

3 PREVENTIVE MAINTENANCE SCHEDULE ........................... 11-13

3.1 PM PARTS............................................................................................11-13

4 TROUBLESHOOTING ............................................................. 11-14

4.1 SERVICE CALL CONDITIONS .............................................................11-14

Rev. 9/2001

CÓPIA NÃO CONTROLADA

SM 1 A294/A295

IMPORTANT SAFETY NOTICES

PREVENTION OF PHYSICAL INJURY

1. Before disassembling or assembling parts of the copier and peripherals, make sure that the copier power cord is unplugged.

2. The wall outlet should be near the copier and easily accessible.

3. Note that some components of the copier and the paper tray unit are supplied with electrical voltage even if the main power switch is turned off.

4. 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.

5. If the Start key is pressed before the copier completes the warm-up period (the Start key starts blinking red and green alternatively), keep hands away from the mechanical and the electrical components as the copier starts making copies as soon as the warm-up period is completed.

6. The inside and the metal parts of the fusing unit become extremely hot while the copier is operating. Be careful to avoid touching those components with your bare hands.

HEALTH SAFETY CONDITIONS

1. Never operate the copier without the ozone filters installed.

2. Toner and developer are non-toxic, but if you get either of them in your eyes by accident, it may cause temporary eye discomfort. Try to remove with eye drops or flush with water as first aid. If unsuccessful, get medical attention.

OBSERVANCE OF ELECTRICAL SAFETY STANDARDS

1. The copier and its peripherals must be installed and maintained by a customer service representative who has completed the training course on those models.

2. The NVRAM on the SICU has a lithium battery which can explode if replaced incorrectly. Replace the NVRAM only with an identical one. The manufacturer recommends replacing the entire NVRAM. Do not recharge or burn this battery. Used NVRAM must be handled in accordance with local regulations.

CÓPIA NÃO CONTROLADA

A294/A295 2 SM

SAFETY AND ECOLOGICAL

NOTES

FOR DISPOSAL

1. Do not incinerate toner bottles or used toner. Toner dust may ignite suddenly when exposed to an open flame.

2. Dispose of used toner, developer, and organic photoconductors in accordance with local regulations. (These are non-toxic supplies.)

3. Dispose of replaced parts in accordance with local regulations.

4. When keeping used lithium batteries in order to dispose of them later, do not put more than 100 batteries per sealed box. Storing larger numbers or not sealing them apart may lead to chemical reactions and heat build-up.

LASER SAFETY

The Center for Devices and Radiological Health (CDRH) prohibits the repair of laser-based optical units in the field. The optical housing unit can only be repaired in a factory or at a location with the requisite equipment. The laser subsystem is replaceable in the field by a qualified Customer Engineer. The laser chassis is not repairable in the field. Customer engineers are therefore directed to return all chassis and laser subsystems to the factory or service depot when replacement of the optical subsystem is required.

WARNING Use of controls, or adjustment, or performance of procedures other than those specified in this manual may result in hazardous radiation exposure.

WARNING WARNING: Turn off the main switch before attempting any of the

procedures in the Laser Unit section. Laser beams can seriously damage your eyes.

CAUTION MARKING:

CÓPIA NÃO CONTROLADA

OVERALL INFORMATION A294/A295

LARGE CAPACITY TRAY B303

DETAILED DESCRIPTIONS A294/A295

A3/DLT TRAY KIT B331

INSTALLATION A294/A295

DIFFERENCES FROM A294 I/A295 I

SERVICE TABLES A294/A295

PREVENTIVE MAINTENANCE A294/A295

REPLACEMENT AND ADJUSTMENT A294/A295

TROUBLESHOOTING A294/A295

3,000-SHEET FINISHER B302

TAB

POSITION 2

TAB

POSITION 1

TAB

POSITION 3

TAB

POSITION 4

TAB

POSITION 6

TAB

POSITION 5

TAB

POSITION 8

TAB

POSITION 7

Rev. 9/2001

CÓPIA NÃO CONTROLADA

OVERALL INFORMATION

CÓPIA NÃO CONTROLADA

SPECIFICATIONS

SM 1-1 A294/A295

Overall

Information

1. OVERALL MACHINE INFORMATION

1.1 SPECIFICATIONS

1.1.1 COPIER ENGINE

Configuration: Console

Copy Process: Dry electrostatic transfer system

Originals: Sheet/Book

Original Size: Maximum: A3/11" x 17"

Minimum: A5, 5

1/2

"x 8

1/2

" (using ADF)

Original Alignment: Rear left corner

Paper Size/Weight:

Size: Mainframe, Tray 1 (Tandem Tray):

A4 sideways and LT sideways

Mainframe, Trays 2 and 3 (Universal Trays):

Europe/Asia:

A5 sideways - A3 lengthwise, 8-kai sideways, 16-kai

N. America:

1/2

" x 8

1/2

" sideways - 11" x 17" lengthwise

LCT, Trays 4 ~ 6:

A4 sideways, B5 sideways, LT sideways, A5, HLT

Duplex Tray: A5/HLT (lengthwise or sideways)

to A3/DLT, except that tab paper cannot be used

Weight: Mainframe, Trays 1 to 3:

52 to 163 g/m

16 to 40 lbs Bond 50 to 60 lbs Cover 90 lbs Index (no Tab)

LCT, Trays 4 and 5:

52 to 216 g/m

16 to 40 lbs Bond 50 to 80 lbs Cover 90 to 110 lbs Index

LCT, Tray 6:

Same as Mainframe, Trays 1 to 3

Duplex Tray:

64 to 163 g/m

20 to 40 lbs Bond 50 to 60 lbs Cover 90 lbs Index (no Tab)

CÓPIA NÃO CONTROLADA

SPECIFICATIONS

A294/A295 1-2 SM

Reproduction Ratios: 7 reduction and 5 enlargement

Metric Version Inch Version

Enlargement

400% 200% 141% 122% 115%

400% 200% 155% 129% 121%

Full Size 100% 100%

Reduction

93% 82% 75% 71% 65% 50% 25%

93% 85% 78% 73% 65% 50% 25%

Zoom: 25 ~ 400%

Copy Speed: A294: Max. 85 CPM (A4/8

1/2

" x 11" sideways)

A295: Max. 105 CPM (A4/8

1/2

" x 11" sideways)

Resolution: Scanning: 600 dpi

Printing: 600 dpi

Gradation: 256 levels

Warm-up Time: Less than 360 s (from Off mode)

First Copy Time: (1st Tray, A4 sideways)

Finisher upper tray: face down

A294: Less than 5.4 s A295: Less than 4.9 s

Finisher upper tray: face up

A294: Less than 4.1 s A295: Less than 3.8 s

Copier: face down

A294: Less than 4.5 s A295: Less than 4.2 s

Copier: face up

A294: Less than 3.2 s A295: Less than 2.9 s

Copy Number Input: Ten-key pad, 1 to 9999

Copy Paper Capacity: 1st Tray: 1,000 sheets (2,000 when used as a tandem

tray) 2nd/3rd Tray: 500 sheets each 4th/5th Tray (LCT): 1,000 sheets each 6th Tray (LCT): 2,500 sheets

Memory Capacity: A294: RAM: 48 MB x 2, HDD: 4.3 GB x 2

A295: RAM: 48 MB x 2, HDD: 6.8 GB x 2

Toner Replenishment: Cartridge exchange (1,450 g/cartridge)

Rev. 6/2000

CÓPIA NÃO CONTROLADA

SPECIFICATIONS

SM 1-3 A294/A295

Overall

Information

Toner Yield: 53 k copies, 20% recycled

(A4 sideways, 6% full black, 1 to 25 copying)

Power Source: North America: 220 ~ 240 V, 60 Hz, 20 A

Europe/Asia: 220 ~ 240 V, 50Hz/60 Hz, 16 A

Power Consumption:

Note: For USA installations, standard 220V (+/10%) wall voltage is acceptable.

A294: N. America Version

Mainframe Only Full System *

Warm-up about 1.96 kW about 1.98 kW

Stand-by about 0.79 kW about 0.8 kW

Copying about 2.24 kW about 2.3 kW

Maximum less than 2.35 kW less than 2.38 kW

A295: N. America Version

Mainframe Only Full System *

Warm-up about 2.51 kW about 2.52 kW

Stand-by about 0.93 kW about 0.95 kW

Copying about 2.67 kW about 2.68 kW

Maximum less than 2.77 kW less than 2.84 kW

A294: Europe Version

Mainframe Only Full System *

Warm-up about 1.89 kW about 1.9 kW

Stand-by about 0.75 kW about 0.77 kW

Copying about 2.14 kW about 2.18 kW

Maximum less than 2.24 kW less than 2.26 kW

A295: Europe Version

Mainframe Only Full System *

Warm-up about 2.38 kW about 2.39 kW

Stand-by about 0.89 kW about 0.9 kW

Copying about 2.52 kW about 2.54 kW

Maximum less than 2.64 kW less than 2.7 kW

*1: Mainframe with the finisher, large capacity tray

Noise Emission *1: A294

Sound Power Level

Mainframe Only Complete System *

Warm-up about 74 dB (A) 78 dB (A)

Stand-by about 59 dB (A) 58 dB (A)

Sound Pressure Level *

Mainframe Only Complete System *

During printing 59 dB (A) 68 dB (A)

Rev. 6/2000

CÓPIA NÃO CONTROLADA

SPECIFICATIONS

A294/A295 1-4 SM

*1: The above measurements made ISO 7779 are actual value. *

: It is measured at the position of the bystander or the operator. During Printing.

: Mainframe with the full options.

Noise Emission *1: A295

Sound Power Level

Mainframe Only Complete System *

Warm-up 75 dB (A) 78 dB (A)

Stand-by 59 dB (A) 58 dB (A)

Sound Pressure Level *

Mainframe Only Complete System *

During printing 61 dB (A) 67 dB (A)

*1: The above measurements made ISO 7779 are actual value. *

: It is measured at the position of the bystander or the operator. During Printing.

: Mainframe with the full options.

Dimensions: (W x D x H)

870 x 735 x 1,476 mm (34.3" x 28.9" x 58.1") (without options)

Weight: 252 kg (without options)

Optional Equipment: Refer to Machine Configuration

1.1.2 ADF

Original Size: Normal Original Mode:

A3 to B6, DLT to HLT

Thin Original Mode:

A3 to B6 sideways, DLT to HLT

Duplex Original Mode:

A3 to A5, DLT to HLT

Original Weight: Normal Original Mode: 52 ~ 156 g/m2, 14 ~ 42 lb

Thin Original Mode: 40 ~ 156 g/m2, 11 ~ 42 lb Duplex Original Mode: 52 ~ 128 g/m2, 14 ~ 34 lb

Table Capacity: 100 sheets (80 g/m2, 20 lb)

Original Feeding Speed: 72 cpm (A4/LT sideways, 1 to 1)

Original Standard Position: Rear left corner

Separation: FRR

Original Transport: One flat belt

Original Feed Order: From the top original

Power Source: DC 24 V and DC 38 V from the copier

Power Consumption: 145 W

Dimensions (W x D x H): 680 x 560 x 150 mm

Rev. 6/2000

CÓPIA NÃO CONTROLADA

MACHINE CONFIGURATION

SM 1-5 A294/A295

Overall

Information

1.2 MACHINE CONFIGURATION

Item Machine Code No.

Mainframe A294 / A295 1 Finisher B302 2 LCT B303 3 Interface Kit Type 850: * B327 4 A3/DLT Tray Kit Type 850

B331

Replaces the tandem LCT

CD-RW (CDROM reader/writer): *

B334 5

Punch Unit A812-30, 31, 32, 57, 67 Inside the Finisher Connector

(for the Tandem Copy feature): *

B328 6

*: When the CD-RW and/or the copy connector cable are/is installed, the interface kit is

required.

A294V502.WMF

46 5

Rev. 6/2000

CÓPIA NÃO CONTROLADA

COMPONENT LAYOUT

A294/A295 1-6 SM

1.3 COMPONENT LAYOUT

1.3.1 COPIER ENGINE

1. Laser Diode Board

2. fθ Lenses

3. Sensor Board Unit

4. Exposure Lamp

5. Cleaning Brush

6. Lamp Regulator

7. Cleaning Blade

8. Charge Corona Unit

9. System Image Control Unit

10. Color LCD

11. Drum

12. Development Unit

13. Registration Roller

14. LCT Relay Roller

15. Transfer Belt Unit

16. Relay Roller

17. Pick-up Roller

18. Vertical Transport Rollers

19. Separation Roller

20. Feed Roller

21. 1st Tray (Tandem, 1,000 sheets each)

22. 2nd Tray (500 sheets)

23. 3rd Tray (500 sheets)

24. Used Toner Bottle

25. Toner Bank Unit

26. Duplex Tray

27. Inverter Unit Paper Exit Roller

28. Inverter Feed Roller

29. Pressure Roller

30. Paper Cooling Pipe

31. Hot Roller

32. Motor Control Unit

33. Oil Supply & Cleaning Web

34. Drum Unit

A294V101.WMF

96 753 41 2

3433

23 22 21 20 19

CÓPIA NÃO CONTROLADA

COMPONENT LAYOUT

SM 1-7 A294/A295

Overall

Information

1.3.2 ADF

1. Separation Roller

2. Feed Belt

3. Pick-up Roller

4. Bottom Plate

5. Original Tray

6. Upper Tray Exit Roller

7. Inverter Gate

8. Inverter Guide Roller

9. Inverter Sensor

10. Right Tray Exit Roller

11. Right Exit Tray

12. Exit Gate

13. Inverter Roller

14. Exit Sensor

15. Upper Exit Tray

16. Transport Belt

17. Registration Sensor

18. Lower Transport Roller

19. Width Sensor

20. Upper Transport Roller

21. Entrance Sensor

B301V001.WMF

863425

18 17 1213141516

CÓPIA NÃO CONTROLADA

PAPER PATH

A294/A295 1-8 SM

1.4 PAPER PATH

1. ADF

2. Optional LCT

3. Tray 3 (500-sheet)

4. Tray 2 (500-sheet Tray)

5. Tray 1 (Tandem Tray)

6. Duplex Unit

7. Finisher

8. Inverter Unit

9. Shift Tray

10. Upper Tray

A294V504.WMF

CÓPIA NÃO CONTROLADA

COPY PROCESS

SM 1-9 A294/A295

Overall

Information

1.5 COPY PROCESS

1. EXPOSURE

A xenon lamp exposes the original. Light reflected from the original passes to the CCD, where it is converted into an analog data signal. This data is converted to a digital signal, processed, and stored in the memory. At the time of printing, the data is retrieved and sent to the laser diode. For multi-copy runs, the original is scanned once only and stored to the hard disk.

2. DRUM CHARGE

An OPC (organic photoconductor) drum is used in this machine. In the dark, the charge corona unit gives a negative charge to the drum. The grid plate ensures that corona charge is applied uniformly. The charge remains on the surface of the drum because the OPC layer has a high electrical resistance in the dark.

A229V508.WMF

A229V510.WMF

CÓPIA NÃO CONTROLADA

COPY PROCESS

A294/A295 1-10 SM

3. LASER EXPOSURE

The processed data from the scanned original is retrieved from the hard disk and transferred to the drum by four laser beams, which form an electrostatic latent image on the drum surface. The amount of charge remaining as a latent image on the drum depends on the laser beam intensity, which is controlled by the laser diode board (LDB).

4. DRUM POTENTIAL SENSOR

The drum potential sensor detects the electric potential on the drum to correct various process control elements.

5. DEVELOPMENT

The magnetic developer brush on the development rollers comes in contact with the latent image on the drum surface. Toner particles are electrostatically attracted to the areas of the drum surface where the laser reduced the negative charge on the drum.

6. IMAGE TRANSFER

Paper is fed to the area between the drum surface and the transfer belt at the proper time to align the copy paper and the developed image on the drum. Then, the transfer bias roller and brush apply a high positive charge to the reverse side of the paper through the transfer belt. This positive charge pulls the toner particles from the drum to the paper. At the same time, the paper is electrically attracted to the transfer belt.

7. PAPER SEPARATION

Paper separates from the drum as a result of the electrical attraction between the paper and the transfer belt. The pick-off pawls also help separate the paper from the drum.

8. ID SENSOR

The laser forms a sensor pattern on the drum surface. The ID sensor measures the reflectivity of the pattern. The output signal is one of the factors used for toner supply control.

9. CLEANING

The cleaning brush removes toner remaining on the drum after image transfer and the cleaning blade scrapes off all remaining toner.

10. QUENCHING

The light from the quenching lamp electrically neutralizes the charge on the drum surface.

CÓPIA NÃO CONTROLADA

DRIVE LAYOUT

SM 1-11 A294/A295

Overall

Information

1.6 DRIVE LAYOUT

1.6.1 COPIER ENGINE

1. Drum Motor

2. Scanner Motor

3. Fusing/Duplex Motor

4. Paper Feed Motor

5. Registration Motor

6. Relay Motor

7. Development Motor

A294V501.WMF

CÓPIA NÃO CONTROLADA

DRIVE LAYOUT

A294/A295 1-12 SM

1.6.2 ADF

1. Pick-up Motor

2. Bottom Plate Motor

3. Feed-in Motor

4. Transport Motor

5. Upper Exit Roller

6. Feed-out Motor

7. Right Exit Roller

8. Transport Belt

9. Lower Transport Roller

10. Upper Transport Roller

11. Separation Roller

12. Feed Belt

13. Pick-up Roller

14. Feed-in Clutch

B301V101.WMF

CÓPIA NÃO CONTROLADA

ELECTRICAL COMPONENT DESCRIPTIONS

SM 1-13 A294/A295

Overall

Information

1.7 ELECTRICAL COMPONENT DESCRIPTIONS

Refer to the electrical component layout in the plastic pouch for the location of the components using the symbols and index numbers.

1.7.1 COPIER ENGINE

Symbol Name Function

Motors

M1 Scanner Drives the 1st and 2nd scanners. M2 Polygonal Mirror Turns the polygonal mirror. M3 Drum Drives the drum, cleaning unit, and transfer belt unit. M4 Development Drives the development unit. M5 Toner Supply Supplies the toner to the toner hopper.

Toner Bank Drives the toner transport coil, which feeds fresh

toner from the toner bank to the toner supply cylinder.

Upper Toner Bottle

Rotates the upper toner bottle to supply toner to the toner entrance tank.

Upper Bottle Cap Opens and closes the inner cap of the upper toner

bottle.

Lower Toner Bottle Rotates the lower toner bottle to supply toner to the

toner entrance tank.

M10

Lower Bottle Cap Opens and closes the inner cap of the lower toner

bottle.

M11

Charge Corona Wire Cleaner

Drives the charge corona wire cleaner.

M12

Fusing/Duplex Drives the fusing unit, duplex unit, inverter unit, and

paper exit rollers.

M13

Paper Feed Drives the paper feed, separation, pick-up, lower

relay, and vertical transport rollers.

M14 Relay Drives the upper relay roller and the LCT relay roller.

M15

1st Tray Lift

Raises and lowers the bottom plate in the 1st paper tray.

M16

2nd Tray Lift Raises and lowers the bottom plate in the 2nd paper

tray.

M17

3rd Tray Lift Raises and lowers the bottom plate in the 3rd paper

tray.

M18 Registration Drives the registration rollers.

M19

Oil Supply/Cleaning Web

Drives the oil supply/cleaning web.

M20

Rear Fence Drive

Moves the paper stack in the left tandem tray to the right tandem tray.

M21

Jogger Drives the jogger fences to square the paper stack in

the duplex unit.

M22 Optics Cooling Fan Removes heat from the scanner optics unit.

M23

Polygonal Mirror Motor Cooling Fan

Removes heat from around the polygonal mirror motor.

M24 LDB Cooling Fan Removes heat from around the LDB.

CÓPIA NÃO CONTROLADA

ELECTRICAL COMPONENT DESCRIPTIONS

A294/A295 1-14 SM

Symbol Name Function

M25 SICU Cooling Fan Removes heat from around the SICU. M26 Drum Cooling Fan Removes heat from the drum.

M27

Development Unit Cooling Fan 1

Removes heat from the development unit.

M28

Development Unit Cooling Fan 2

Removes heat from the development unit.

M29

Paper Cooling Pipe Fan

Removes heat from the paper cooling pipe.

M30 Duplex Cooling Fan Removes heat from around the duplex unit. M31 Exhaust Fan Removes heat from around the fusing unit. M32 Steam Removal Fan Removes water vapor from around the fusing unit. M33 PSU Cooling Fan 1 Removes heat from the PSU. M34 PSU Cooling Fan 2 Removes heat from the PSU.

Sensors

Scanner HP Informs the CPU when the 1st and 2nd scanners are

at home position.

Original Width

Detects original width. This is one of the APS (Auto Paper Select) sensors.

Original Length 1 Detects original length.

This is one of the APS (Auto Paper Select) sensors.

Original Length 2 Detects original length.

This is one of the APS (Auto Paper Select) sensors. S5 Drum Potential Detects the drum surface potential. S6 Toner Density (TD) Detects the amount of toner in the developer.

Image Density (ID)

Detects the density of the ID sensor pattern on the

drum. S8 Toner Hopper Detects toner in the toner hopper. S9 Toner Supply Motor Monitors the toner supply motor.

S10 Upper Toner Bottle Detects when the upper toner bottle is set. S11 Lower Toner Bottle Detects when the lower toner bottle is set.

S12

Upper Bottle Inner Cap

Detects when the inner cap of the upper toner bottle

is opened.

S13

Lower Bottle Inner Cap

Detects when the inner cap of the lower toner bottle is

opened.

S14

Toner Collection Bottle

Detects when the waste toner collection bottle is set.

S15 Toner Overflow Detects when the waste toner collection bottle is full. S16 Toner Near End Detects toner near end in the toner bank unit.

S17

1st Paper Feed Controls the 1st paper feed clutch on/off timing and

the 1st pick-up solenoid off timing.

S18

2nd Paper Feed

Controls the 2nd paper feed clutch on/off timing and

the 2nd pick-up solenoid off timing.

S19

3rd Paper Feed Controls the 3rd paper feed clutch on/off timing and

the 3rd pick-up solenoid off timing.

S20

1st Tray Lift Detects when the paper in tray 1 is at the correct

height for paper feed.

CÓPIA NÃO CONTROLADA

ELECTRICAL COMPONENT DESCRIPTIONS

SM 1-15 A294/A295

Overall

Information

Symbol Name Function

S21

2nd Tray Lift Detects when the paper in tray 2 is at the correct

height for paper feed.

S22

3rd Tray Lift Detects when the paper in tray 3 is at the correct

height for paper feed.

S23 1st Paper End Informs the CPU when tray 1 runs out of paper. S24 2nd Paper End Informs the CPU when tray 2 runs out of paper. S25 3rd Paper End Informs the CPU when tray 3 runs out of paper.

S26

Rear Fence HP Informs the CPU when the tandem tray rear fence is

in the home position.

S27

Rear Fence Return

Informs the CPU when the tandem tray rear fence is

in the return position.

S28

Front Side Fence Open

Detects whether the tandem tray front side fence is

opened.

S29

Front Side Fence Closed

Detects whether the tandem tray front side fence is

closed.

S30

Rear Side Fence Open

Detects whether the tandem tray rear side fence is

opened.

S31

Rear Side Fence Closed

Detects whether the tandem tray rear side fence is

closed.

S32

Base Plate Down Detects when the bottom plate is completely lowered,

to stop the 1st tray lift motor.

S33

1st Tray Paper Height 1

Detects the paper height in the 1st tray.

S34

1st Tray Paper Height 2

Detects the paper height in the 1st tray.

S35

1st Tray Paper Height 3

Detects the paper height in the 1st tray.

S36

1st Tray Paper Height 4

Detects the paper height in the 1st tray.

S37

Left 1st Tray Paper

Detects whether there is paper in the left side of the

1st tray.

S38

Right 1st Tray Paper Detects whether there is paper in the right side of the

1st tray, allowing the tray to lift if paper is present.

S39 Duplex Inverter Detects misfeeds.

S40

Duplex Entrance Detects the leading and trailing edges of the paper to

determine the reverse roller solenoid on or off timing.

S41 Duplex Transport 1 Detects the position of paper in the duplex unit. S42 Duplex Transport 2 Detects the position of paper in the duplex unit. S43 Duplex Transport 3 Detects the position of paper in the duplex unit.

S44

Duplex Jogger HP Detects if the duplex jogger fences are at the home

position or not.

S45 LCT Relay Detects misfeeds. S46 Relay Detects misfeeds.

S47

Registration

Detects misfeeds and controls registration clutch

on/off timing.

S48

Guide Plate Position

Detects whether the registration guide plate is open

or closed.

CÓPIA NÃO CONTROLADA

ELECTRICAL COMPONENT DESCRIPTIONS

A294/A295 1-16 SM

Symbol Name Function

S49

Oil Supply/Cleaning Web End

Detects when the oil supply/cleaning web has been

used up.

S50 Fusing Exit Detects misfeeds. S51 Exit Detects misfeeds.

Switches

SW1

Main Power Provides power to the machine. If this is off, there is

no power supplied to the machine.

SW2

Right Front Door Safety 1

Cuts the +24 V dc power line for the fusing/duplex

motor.

SW3

Right Front Door Safety 2

Detects if the front door is open or not, and cuts the

+24 V dc power line for the IOB.

SW4

Right Front Door Safety 3

Cuts the +5 V LD dc power line.

SW5

Right Front Door Safety 4

Cuts the +5 V LD dc power line.

SW6

Left Front Door Safety 1

Cuts the +24 V dc power line for the fusing/duplex

motor.

SW7

Left Front Door Safety 2

Detects if the front door is open or not, and cuts the

+24 V dc power line for the IOB.

SW8

Left Front Door Safety 3

Cuts the +5 V LD dc power line.

SW9

Left Front Door Safety 4

Cuts the +5 V LD dc power line.

SW10

2nd Tray Paper Size Determines the size of paper in tray 2. Also detects

when the tray has been placed in the machine.

SW11

3rd Tray Paper Size Determines the size of paper in tray 3. Also detects

when the tray has been placed in the machine.

Solenoids

SOL1

Transfer Belt Lift Controls the up-down movement of the transfer belt

unit.

SOL2

1st Pick-up Controls the up-down movement of the pick-up roller

in tray 1.

SOL3

2nd Pick-up

Controls the up-down movement of the pick-up roller

in tray 2.

SOL4

3rd Pick-up

Controls the up-down movement of the pick-up roller

in tray 3.

SOL5

1st Separation Roller

Controls the up-down movement of the separation

roller in tray 1.

SOL6

2nd Separation Roller

Controls the up-down movement of the separation

roller in tray 2.

SOL7

3rd Separation Roller

Controls the up-down movement of the separation

roller in tray 3.

SOL8

Front Side Fence Opens and closes the front side fence in the tandem

tray.

SOL9

Rear Side Fence Opens and closes the rear side fence in the tandem

tray.

CÓPIA NÃO CONTROLADA

ELECTRICAL COMPONENT DESCRIPTIONS

SM 1-17 A294/A295

Overall

Information

Symbol Name Function

SOL10

Tandem Tray Connect

Connects/disconnects the two halves of the tandem

tray.

SOL11

Left 1st Tray Lock Locks the left tandem tray while paper is being

transported from left tray to right tray.

SOL12

Duplex Inverter Gate

Moves the junction gate to direct copies to the duplex

tray or to the paper exit.

SOL13

Reverse Roller Controls the up-down movement of the reverse roller

in the duplex unit.

SOL14

Inverter Guide Plate Controls the up-down movement of the inverter feed

guide plate in the duplex unit.

SOL15

Guide Plate

Opens the guide plate when a paper misfeed occurs

around this area.

SOL16

Inverter Gate Moves the junction gate to direct copies to the

duplex/inverter unit or to the paper exit unit.

Magnetic Clutches

MC1

Toner Supply Coil Transfers drive from the toner bank motor to the toner

transport coil, to transport toner towards the hopper.

MC2

Toner Supply Roller

Turns the toner supply roller to supply toner from the

toner hopper to the development unit.

MC3 1st Paper Feed Starts paper feed from tray 1. MC4 2nd Paper Feed Starts paper feed from tray 2. MC5 3rd Paper Feed Starts paper feed from tray 3.

MC6

Inverter Exit Roller

Releases the drive from the inverter exit roller in the

duplex unit.

MC7

Duplex Transport Drives the duplex transport rollers to transport the

paper to the duplex feed rollers.

MC8

Duplex Feed Starts paper feed out of the duplex tray back into the

machine via to the relay rollers.

MC9

1st Vertical Transport

Drives the 1st vertical transport rollers.

MC10

2nd Vertical Transport

Drives the 2nd vertical transport rollers.

MC11

3rd Vertical Transport

Drives the 3rd vertical transport rollers.

MC12

Upper Relay

Drives the upper relay rollers (between tray1 and the

registration rollers)

MC13

LCT Relay Drives the relay rollers for paper feed into the

machine from the LCT.

MC14

Lower Relay Drives the lower relay rollers (between paper trays 1

and 2).

PCBs

PCB1

BCU (Base Engine Control Unit)

Controls all base engine functions both directly and

through other control boards.

PCB2

SICU (Scanner Image Control Unit)

Controls image processing, the laser diode, and the

polygonal mirror motor.

CÓPIA NÃO CONTROLADA

ELECTRICAL COMPONENT DESCRIPTIONS

A294/A295 1-18 SM

Symbol Name Function

PCB3

PSU (Power Supply Unit)

Provides dc power to the system and ac power to the

fusing lamp and heaters.

PCB4

IOB (Input/Output Board)

Controls the paper feed components.

PCB5

SBU (Sensor Board Unit)

Contains the CCD, and outputs a video signal to the

SBICU board.

PCB6

MCU (Motor Control Unit)

Drives the scanner motor.

PCB7 Lamp Regulator Provides dc power to the exposure lamp.

PCB8

Polygonal Mirror Motor Control

Drives and controls the polygonal mirror motor.

PCB9 LDB Controls the laser diode. PCB10 AC Drive Drives the ac components. PCB11 Operation Panel Controls the components of the operation panel. PCB12 Operation Key Controls the operation switch.

Lamps

Exposure Lamp Applies high intensity light to the original for

exposure. L2 Fusing Lamp 1 Provides heat to the hot roller. L3 Fusing Lamp 2 Provides heat to the hot roller. L4 Fusing Lamp 3 Provides heat to the hot roller.

Quenching Neutralizes any charge remaining on the drum

surface after cleaning.

Power Packs

PP1

Charge/bias/grid

Provides high voltage for the charge corona wires,

grid plate, and the development roller.

PP2 Transfer Provides high voltage for the transfer belt.

Others

CB1

Circuit Breaker Provides back-up high current protection for the

electrical components.

Optics Anti-Condensation (option)

Turns on when the main switch is off to prevent

moisture from forming on the optics.

Drum (option) Turns on when the main switch is off to prevent

moisture from forming around the drum.

Tray Heater 1 (option)

Turns on when the main switch is off to keep paper

dry in the paper tray.

Tray Heater 2 (option)

Turns on when the main switch is off to keep paper

dry in the paper tray.

HDD1

HDD Scanned image data is compressed and held here

temporarily.

HDD2

HDD Scanned image data is compressed and held here

temporarily.

NF1 Noise Filter Removes noise from the power line.

CÓPIA NÃO CONTROLADA

ELECTRICAL COMPONENT DESCRIPTIONS

SM 1-19 A294/A295

Overall

Information

Symbol Name Function

SD1

Laser Synchronization Detector

Detects the laser beam at the start of the main scan.

TC1 Total Counter Counts the number of copies.

TF1

Fusing Thermofuse

Opens the fusing lamp circuit if the fusing unit

overheats.

TH1 Fusing Thermistor Detects the temperature of the hot roller.

1.7.2 ADF

Symbol Name Function Index No.

Motors

M1 Pick-up Moves the pick-up roller up and down. 3

Feed-in

Drives the feed belt, and the separation,

pick-up, and transport rollers.

M3 Transport Belt Drives the transport belt. 9 M4 Feed-out Drives the exit and inverter rollers. 14 M5 Bottom Plate Moves the bottom plate up and down. 7

Sensors

APS Start

Informs the CPU when the DF is opened

and closed (for platen mode) so that the

original size sensors in the copier can

check the original size.

S2 DF Position Detects whether the DF is lifted or not. 13

Original Set

Detects whether an original is on the

table.

Bottom Plate HP Detects whether the bottom plate is in

the down position or not.

Bottom Plate Position

Detects when the original is at the correct

position for feeding.

Pick-up Roller HP

Detects whether the pick-up roller is up

or not.

Entrance Detects when to restart the pick-up motor

to lift up the pick-up roller, detects when

to change the feed motor direction,

detects the trailing edge of the original to

finish checking the original length, and

checks for misfeeds.

Registration Detects the leading edge of the original

to check the original length, detects when

to stop the original on the exposure

glass, and checks for misfeeds.

S9 Original Width 1 Detects the original width. 22

S10 Original Width 2 Detects the original width. 23

CÓPIA NÃO CONTROLADA

ELECTRICAL COMPONENT DESCRIPTIONS

A294/A295 1-20 SM

Symbol Name Function Index No.

S11 Original Width 3 Detects the original width. 24 S12 Original Length Detects the original length. 25

S13

Exit

Detects when to stop the transport belt

motor and checks for misfeeds.

S14

Inverter Detects when to turn the inverter gate

and exit gate solenoids off and checks

for misfeeds.

S15

Feed Cover Detects whether the feed cover is open

or not.

S16

Exit Cover Detects whether the exit cover is open or

not.

Solenoids

SOL1 Exit Gate Opens and closes the exit gate. 16 SOL2 Inverter Gate Opens and closes the inverter gate. 11

Magnetic Clutches

MC1

Feed-in

Drives the feed belt, separation roller,

and pick-up roller.

PCBs

PCB1

DF Main Controls the DF and communicates with

the main copier boards.

PCB2

DF Indicator Indicates whether an original has been

placed in the feeder, and indicates

whether SADF mode has been selected.

CÓPIA NÃO CONTROLADA

DETAILED DESCRIPTIONS

CÓPIA NÃO CONTROLADA

DOCUMENT FEEDER

SM 2-1 A294/A295

Detailed

Descriptions

2. DETAILED SECTION DESCRIPTIONS

2.1 DOCUMENT FEEDER

2.1.1 PICK-UP ROLLER RELEASE

When the original set sensor is off (no original on the original tray), the pick-up roller stays in the up position.

When the original set sensor turns on (or when the trailing edge of a page passes the entrance sensor while pages remain on the original tray), the pick-up motor [A] turns on. The cam [B] rotates away from the pick-up roller release lever [C]. The lever then rises and the pick-up roller [D] drops onto the original.

When the original reaches the entrance sensor, the pick-up motor turns on again. The cam pushes the lever down, and the pick-up roller rises until the pick-up roller HP sensor [E] detects the actuator [F].

B301D103.WMF

[A]

[D]

[C]

[E]

[B]

[F]

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DOCUMENT FEEDER

A294/A295 2-2 SM

2.1.2 BOTTOM PLATE LIFT

When an original is placed on the original tray, the original set sensor [A] turns on, the pick-up roller [B] drops on to the original, and the bottom plate position sensor [C] turns off. Then the bottom plate motor [D] turns on and lifts the bottom plate [E] by raising the lift lever [F] until the bottom plate position sensor turns on.

The level of the pick-up roller drops as the stack of originals becomes smaller, and eventually, the bottom plate position sensor [C] turns off. Then, the bottom plate motor turns on and lifts the bottom plate until the bottom plate position sensor turns on. This keeps the original at the correct height for feeding.

B301D105.WMF

[F]

[D]

[F]

[A]

[B]

[C]

[E]

[B]

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DOCUMENT FEEDER

SM 2-3 A294/A295

Detailed

Descriptions

2.1.3 PICK-UP AND SEPARATION

The original separation system is a Feed and Reverse Roller (FRR) system. The pick-up roller [A], feed belt [B], and separation roller [C] are driven by the feed-in motor [D].

To drive this mechanism, the feed-in motor [D] and feed-in clutch [E] turn on.

When two sheets of originals are fed by the pick-up roller, the separation roller turns in the opposite direction to the feed belt and the 2nd sheet is pushed back to the original tray. When there is only one sheet between the feed belt and separation roller, the separation roller rotates in the same direction as the feed belt. This is because the separation roller contains a torque limiter.

B301D102.WMF

B301D506.WMF

[E]

[A]

[B]

[D]

[A]

[C]

[B]

[C]

CÓPIA NÃO CONTROLADA

DOCUMENT FEEDER

A294/A295 2-4 SM

2.1.4 ORIGINAL FEED

When the leading edge of the original turns the entrance sensor [A] on, the feed-in clutch [B] turns off and the drive for the feed belt is released. The original is fed by the transport rollers [C].

At the same time, the pick-up motor starts again and the pick-up roller [D] is lifted up. When the pick-up roller HP sensor turns on, the pick-up motor stops (see Pickup Roller Release).

B301D109.WMF

[B]

[D]

[A]

[C]

CÓPIA NÃO CONTROLADA

DOCUMENT FEEDER

SM 2-5 A294/A295

Detailed

Descriptions

2.1.5 ORIGINAL SIZE DETECTION

The DF detects the original size by combining the readings of original length sensor [A], and original width sensors-1 [B], -2 [C], and -3 [D].

Original Length

The original length sensor and the disk [E] (connected to the transport roller) generate a pulse signal. The CPU counts pulses, starting when the leading edge of the original turns on the registration sensor [F], until the trailing edge of the original turns off the entrance sensor [G].

Original Width

The CPU detects original width using three original width sensors -1, -2, -3 as shown above. Three small circles on the diagram indicate the positions of the sensors.

B301D104.WMF

B301D503.WMF

[E]

[G]

[D]

[A]

[F]

[C]

[B]

CÓPIA NÃO CONTROLADA

DOCUMENT FEEDER

A294/A295 2-6 SM

2.1.6 ORIGINAL TRANSPORT

The transport belt [A] is driven by the transport belt motor [B]. The transport belt motor starts when the copier sends an original feed-in signal.

Inside the transport belt are six pressure rollers which maintain the correct pressure between the belt and original. The pressure roller [C] closest to the left original scale is made of rubber for the stronger pressure needed for thick originals. The other rollers are sponge rollers.

Normally, originals are manually placed at the left rear corner, so an original [D] fed from the DF must also be at this position. But if the original is fed along the rear scale [E], original skew, jam, or wrinkling may occur.

To prevent such problems, the original transfer position is set to 3.5 mm away from the rear scale as shown. The 3.5 mm gap is compensated for by changing the starting position of the main scan.

B301D106.WMF

B301D509.WMF

[C]

[E]

[B]

[A]

3.5 mm

[D]

CÓPIA NÃO CONTROLADA

DOCUMENT FEEDER

SM 2-7 A294/A295

Detailed

Descriptions

2.1.7 ORIGINAL SKEW CORRECTION

The transport belt motor remains energized to carry the original about 7 mm past the left scale [A] (see the middle drawing). Then the motor stops and reverses to feed the original back against the left scale (see the bottom drawing). This forces the original to hit the left scale, which aligns the trailing edge to minimize original skew on the exposure glass.

If thin original mode is selected, the original is not forced back against the left scale. This is to prevent damage to the original.

After a two-sided original has been inverted to copy the 2nd side, it is fed in from the inverter against the left scale (see the bottom drawing; the top two drawings do not apply in this mode).

The amount of reverse feed against the left scale can be adjusted with SP modes.

B301D500.WMF

[A]

7 mm

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DOCUMENT FEEDER

A294/A295 2-8 SM

2.1.8 ORIGINAL INVERSION AND FEED-OUT

General Operation

When the scanner reaches the return position, the copier’s CPU sends the feed-out signal to the DF. When the DF receives the feed-out signal, the transport belt motor and feed-out motor [A] turn on. The original is then fed out to the exit tray or fed back to the exposure glass after reversing in the inverter section.

This DF has two exit trays. For single-sided original mode, the original is fed out to the right exit tray and for double-sided original mode, the original is fed out to the upper exit tray.

This causes the originals to be fed out in the correct order on the exit trays and allow the maximum one-to-one copy speed for each mode.

B301D107.WMF

[A]

Rev. 10/2000

CÓPIA NÃO CONTROLADA

DOCUMENT FEEDER

SM 2-9 A294/A295

Detailed

Descriptions

Original Inversion

When the DF receives the original invert signal from the copier, the transport belt motor, feed-out motor, exit gate solenoid [A], and inverter gate solenoid [B] turn on and the original is fed back to the exposure glass through the inverter roller [C], exit gate [D], inverter guide roller [E], inverter gate [F], and inverter roller.

The transport belt motor turns in reverse shortly after the leading edge of the original turns on the inverter sensor [G], and feeds the original to the left scale.

B301D113.WMF

[C]

[A]

[B]

[F]

[G]

[D]

[E]

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DOCUMENT FEEDER

A294/A295 2-10 SM

Original Exit (Single-Sided Original Mode)

The exit gate solenoid [A] remains off and the original is fed out to the right exit tray. The transport belt motor turns off after the exit sensor [B] turns off.

To stack the originals neatly on the exit tray, the feed-out motor speed is reduced about 30 mm before the trailing edge of the original turns off the exit sensor.

B301D111.WMF

[B]

[A]

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DOCUMENT FEEDER

SM 2-11 A294/A295

Detailed

Descriptions

Original Exit (Double-Sided Original Mode)

The exit gate solenoid [A] turns on and the inverter gate solenoid [B] remains off, and the original is fed out to the upper tray. The transport belt motor turns off when the trailing edge of the original passes through the exit sensor [C].

To stack the originals neatly on the upper tray, the feed-out motor speed is reduced shortly after the trailing edge of the original turns off the inverter sensor [D].

B301D112.WMF

[A]

[B]

[D]

[C]

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DOCUMENT FEEDER

A294/A295 2-12 SM

2.1.9 JAM CONDITIONS

Feed-in

1. The entrance sensor [A] is still off 500 ms after the feed-in motor turned on.

2. The registration sensor [B] is still not off 300 ms after the feed-in motor speed increased.

3. The entrance sensor is still on when the feed-in and transport motors have fed the original 442 mm after the registration sensor turned on.

Feed-out

4. The registration sensor is still on when the feed-in and transport motors have fed the original 751 mm after the registration sensor turned on.

5. The exit sensor [C] is still off when the transport and feed-out motors have fed the original 129 mm after the feed-out motor turned on.

6. The exit sensor is still on when feed-out motor has fed the original X mm (X = original length x 1.3) after the exit sensor turned on.

Inversion

7. The exit sensor is still off when the transport and exit motors have fed the original 198 mm after the transport motor turned on to feed the original to the inverter section.

8. The exit sensor is still on when the feed-out motor has fed the original X mm (X = original length x 1.3) after the exit sensor turned on.

9. The inverter sensor [D] is still off when the transport and feed-out motors have fed the original 96 mm after the exit sensor turned on.

10. The inverter sensor is still off when the transport and feed-out motors have fed the original 96 mm to the exposure glass after the exit sensor turned off.

 

B301D501.WMF

[B]

[A]

[D]

[C]

CÓPIA NÃO CONTROLADA

SCANNING

SM 2-13 A294/A295

Detailed

Descriptions

2.2 SCANNING

2.2.1 OVERVIEW

The original is illuminated by the exposure lamp (a xenon lamp) [A]. The image is reflected onto a CCD (Charge Coupled Device) [B] via the 1st, 2nd, and 3rd mirrors, and through the lens [C].

The 1st scanner consists of the exposure lamp, the lamp regulator and the 1st mirror.

There are two fans, optics cooling fan [D] and the SICU cooling fan on the right side of the optics cavity to draw cool air inside. The hot air exits through the vents in the upper cover. The optics cooling fan is turned on when the scanner motor starts and it turns off 10 seconds after the scanner motor turns off. The SICU cooling fan operates whenever the operation switch is on.

If the optional optics anti-condensation heater [E] is installed, it turns on while the main switch is off, to prevent moisture from forming on the optics.

A294D001.WMF

[A]

[D]

[E]

[C] [B]

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SCANNING

A294/A295 2-14 SM

2.2.2 SCANNER DRIVE

The scanner drive motor is a dc servo motor. The 1st and 2nd scanners [A, B] are driven by the scanner drive motor [C] through the timing belt [D], scanner drive pulley [E], scanner drive shaft [F], and two scanner wires [G].

The MCU board controls the scanner drive motor. In full size mode, the 1st scanner speed is 425 mm/s during scanning. The 2nd scanner speed is half that of the 1st scanner.

In reduction or enlargement mode, the scanning speed depends on the magnification ratio. The returning speed is always the same, whether in full size or magnification mode. The image length is changed in the sub scan direction by changing the scanner drive motor speed, and in the main scan direction it is changed by image processing on the SICU board.

Magnification in the sub-scan direction can be adjusted by changing the scanner drive motor speed using SP4-008.

A294D003.WMF

[G]

[A]

[B]

[E]

[D]

[C]

[F]

CÓPIA NÃO CONTROLADA

SCANNING

SM 2-15 A294/A295

Detailed

Descriptions

2.2.3 ORIGINAL SIZE DETECTION IN BOOK MODE

There are three reflective sensors in the optics cavity for original size detection. The original width sensor [A] detects the original width, and the original length sensor-1 [B] and original length sensor-2 [C] detect the original length. These are the APS (Auto Paper Select) sensors.

Inside each APS sensor, there is an LED [D] and either three photoelectric devices [E] (for the width sensor) or one photoelectric device (for each length sensor). In the width sensor, the light generated by the LED is separated into three beams and each beam scans a different point of the exposure glass (in each length sensor, there is only one beam). If the original or DF cover is present over the scanning point, the beam is reflected and each reflected beam exposes a photoelectric device and activates it.

While the main switch is on, these sensors are active and the original size data is always sent to the main CPU. However, the main CPU checks the data only when the DF is being closed.

A294D052.WMF

A294D535.WMF

[B]

[D]

[E]

[C]

[A]

CÓPIA NÃO CONTROLADA

SCANNING

A294/A295 2-16 SM

Original Size

Length Sensor

Width Sensor

A4/A3 Version LT/DLT Version 2 1 3 4 5

SP4301 Display

A3 11" x 17"

❍❍❍❍❍

00011111

B4 10" x 14"

❍❍❍❍✗

00011110

F4 8

1/2

" x 14" (8" x 13")

❍❍❍✗ ✗

00011100

A4-L 8

1/2

" x 11"

✗❍❍✗✗

00001100

B5-L —

✗❍✗✗✗

00001000

A5-L 5

1/2

" x 8

1/2

✗✗✗✗✗

00000000

A4-S 11" x 8

1/2

✗ ✗ ❍❍❍

00000111

B5-S —

✗✗❍❍✗

00000110

A5-S 8

1/2

" x 5

1/2

✗✗❍✗✗

00000100

-L: Lengthwise -S: Sideways ❍:High (Paper Present) ✗: Low

The original size data is taken by the main CPU when the DF position sensor is activated. This is when the DF is positioned about 12 cm above the exposure glass. At this time, only the sensor(s) underneath the original receive the reflected light and switch on. The other sensor(s) are off. The main CPU recognizes the original size from the on/off signals from the five sensors.

If the copy is made with the ADF open, the main CPU decides the original size from the sensor outputs when the Start key is pressed.

The above table shows the outputs of the sensors for each original size. This original size detection method eliminates the necessity for a pre-scan and increases the machine productivity.

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IMAGE PROCESSING

SM 2-17 A294/A295

Detailed

Descriptions

2.3 IMAGE PROCESSING

2.3.1 OVERVIEW

The CCD generates an analog video signal. The SBU (Sensor Board Unit) converts the analog signal to an 8-bit digital signal, then it sends the digital signal to the SICU (Scanner and Image Processing Control Unit) board.

The SICU board can be divided into two image processing blocks: the IPU (Image Processing Unit) and the MSU (Memory Supercharger Unit). These two ICs mainly do the following:

• IPU: Auto shading, filtering, magnification, γ correction, gradation

processing, and video path control

• MSU: Image compression, image rotation, interface with HDD controller,

image repeat, and combine originals

Finally, the SICU board sends the video data to the laser diode array (LDA) on the LD drive board (LDB).

SBU

CCD

PWM

Drum

SICU

Controller

(GAVD)

IPU MSU

HDD2

HDD1

LDB

PWM

LDD

LDA

A294D578.WMF

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IMAGE PROCESSING

A294/A295 2-18 SM

2.3.2 SBU

The CCD converts the light reflected from the original into an analog signal. The CCD line has 7,500 pixels and the resolution is 600 dpi (23.6 lines/mm).

The CCD has four output lines: OS1, OS2, OS3, and OS4. OS1 and OS2 are for the first half of the scan line (Non-operation side), and OS3 and OS4 are for the last half of the scan line (Operation side). There are two analog processing ICs; one handles the first half line (OS 1 and OS2) and the other handles the last half line (OS3 and OS4). The analog processing IC performs the following operations:

1) Combines the odd and even signals into one line signal.

2) Adjust the black reference level of each CCD output channel.

3) Amplifies the analog signal from the CCD.

After the above processing, the analog signals are converted to 8-bit signals by the A/D converter. This gives a value for each pixel on scale of 256 grades. Then, the two 8-bit signals are sent to the SICU board through the LVDS (Low Voltage Differential Signaling). The LVDS is a noise-resistant interface.

SICUSBU

OS4

CCD

Analog

Processing (First)

Analog

Processing (Last)

A/D 2

A/D 1

8-bit data

LVDS

8-bit data

LVDS

IPUGA

OS3

OS2

OS1

A294D579.WMF

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IMAGE PROCESSING

SM 2-19 A294/A295

Detailed

Descriptions

2.3.3 AUTO IMAGE DENSITY (ADS)

This mode prevents the background of an original from appearing on copies.

The copier scans the auto image density detection area [A]. This corresponds to a narrow strip at one end of the main scan line, as shown in the diagram. As the scanner scans down the page, the IPU on the SICU detects the peak white level for each scan line, within this narrow strip only. From this peak white level, the IPU determines the reference value for A/D conversion for the scan line. Then, the IPU sends the reference value to the A/D controller on the SBU.

When an original with a gray background is scanned, the density of the gray area is the peak white level density. Therefore, the original background will not appear on copies. Because peak level data is taken for each scan line, ADS corrects for any changes in background density down the page.

As with previous digital copiers, the user can select manual image density when selecting auto image density mode and the machine will use both settings when processing the original.

128.5 mm

10 mm

0.5 mm

Sub scan direction

A294D581.WMF

[A]

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IMAGE PROCESSING

A294/A295 2-20 SM

2.3.4 IMAGE PROCESSING STEPS AND RELATED SP MODE

The following tables shows the image processing path and the related SP modes used for each image processing mode.

The user can adjust many of the image processing parameters with a UP mode (Copy/Document Server Features – General Features – Original Mode Level), using fixed settings such as Sharp, Normal, and Soft. Each of these fixed settings has different parameter settings. The user’s changes do not affect the SP mode settings.

If the user is not satisfied with any of the available settings for this UP mode, the technician can adjust the SP modes. However, the SP mode settings are not used unless the user selects ‘Service Mode’ with the UP Mode.

For more details about the settings available for the user, see Service Tables – Image Quality Setting by UP Mode.

Soft

Photo Priority

Screened Photo

Soft

Sharp

Text Priority

Glossy Photo

Sharp

Normal

Text

Text/Photo

Pale

Generation

Photo

Service Mode

A294D011.WMF

Rev. 2/2000

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IMAGE PROCESSING

SM 2-21 A294/A295

Detailed

Descriptions

Text Mode

MTF filtering is used in text mode. The MTF filtering coefficient and strength can be adjusted individually for both main and sub scan. Low density originals are produced better when a stronger MTF filter is selected, but in this case, moiré tends to appear.

With UP Mode (Copy/Document Server Features – General Features – Original Mode Level), the user can select ‘Soft’, ‘Normal’, ‘Sharp’, and ‘SP Mode Changed’. The settings of the SP modes indicated with an asterisk (*) are not used unless the user selects ‘Service Mode’.

Image Processing Steps Related SP Modes

Input Correction 1

•

SP4903-065 * (Scanner Gamma Threshold Level)

•

SP4903-070 * (Background Erase Level)

Input Correction 2

•

SP4903-060 (Independent Dot Erase Level)

Filtering

•

SP4903-010 to 011 * (Pre-Filter Coefficient)

•

SP4903-020 to 035 * (MTF Filter Strength)

Magnification

•

SP2909-001 (Main Scan Magnification)

ID Control

•

SP4903-84 * (Scanner gamma setting)

Gradation

•

SP4903-78 to 80 *, 4904-20 (Line Width Correction Type)

Auto Shading

Background Erase

Independent Dot Erase

MTF

Main Scan Magnification

γ Correction

Error Diffusion/

Line Width Correction

Rev. 2/2000

CÓPIA NÃO CONTROLADA

IMAGE PROCESSING

A294/A295 2-22 SM

Photo Mode

Normally, the smoothing filter is used in photo mode but MTF filtering can also be selected with SP mode.

With UP Mode (Copy/Document Server Features – General Features – Original Mode Level), the user can select ‘Screen Printed’, ‘Normal’, ‘Continuous Tone’, and ‘SP Mode Changed’. The settings of the SP modes indicated with an asterisk (*) are not used unless the user selects ‘Service Mode’.

When the user selects “Normal Paper” and “Continuous Tone”, error diffusion is used for the gradation process. However, if the user selects “Screen Printed”, dither processing is used.

Image Processing Path Related SP Modes

Input Correction 1

Input Correction 2

•

SP4903-66 * (Scanner Gamma Thresh Level)

•

SP4903-071 * (Background Erase Level)

Filtering

•

SP4903-012 * (Pre Filter Coefficient)

•

SP4903-009 * (Filter Type Selection)

•

SP4903-036 to 038 * (Smoothing/MTF Filter Coefficient Level in Photo Mode)

•

SP4904-006 (Smoothing Filter Level)

Magnification

•

SP2909-001 (Main Scan Magnification)

ID Control

Gradation

•

SP4904-002 * (Grayscale Process Selection: Dither or Error Diffusion)

Auto Shading

Background Erase

Smoothing/MTF

Main Scan Magnification

γ Correction

Error Diffusion/

Dither Matrix

Rev. 2/2000

CÓPIA NÃO CONTROLADA

IMAGE PROCESSING

SM 2-23 A294/A295

Detailed

Descriptions

Text/Photo Mode

MTF filtering is used for text/photo mode.

With UP Mode (Copy/Document Server Features – General Features – Original Mode Level), the user can select ‘Photo Mode’, ‘Normal’, ‘Text Mode’, and ‘SP Mode Changed’. The settings of the SP modes indicated with an asterisk (*) are not used unless the user selects ‘Service Mode’.

Image Processing Path Related SP Modes

Input Correction 1

•

SP4930-67 * (Scanner Gamma Thresh Level)

•

SP4903-072 * (Background Erase Level)

•

SP4906 * (On/Off in Text/Photo Mode)

Input Correction 2

•

SP4903-062 (Independent Dot Erase Level)

Filtering

•

SP4903-013 to 014 * (Pre Filter Coefficient)

•

SP4903-039 to 054 * (Filter Level and Strength)

•

SP4904-007 (Texture Erase Filter Level)

Magnification

•

SP2909-001 (Main Scan Magnification)

ID Control

•

SP4903-85 * (Scanner gamma setting)

Gradation

•

SP4904-003, 005 * (Error Diffusion)

•

SP4903-81 to 83 *, SP4904-22 (Line Width Correction Type)

Auto Shading

Background Erase

Independent Dot Erase

MTF

Main Scan Magnification

γ Correction

Error Diffusion/

Line Width Correction

Rev. 2/2000

CÓPIA NÃO CONTROLADA

IMAGE PROCESSING

A294/A295 2-24 SM

Pale Mode

The image processing for pale mode is basically the same as in text mode. However, the contrast of the original is low. So, to preserve details, a stronger MTF filter is used. Also, the independent dot erase level is set at a lower level, so that only the faintest of dots are deleted; this ensures that dotted lines and periods are not deleted.

Image Processing Path Related SP Modes

Input Correction 1

•

SP4903-068 * (Scanner Gamma Thresh Level)

•

SP4903-73 * (Background Erase Level)

Input Correction 2

•

SP4903-063 (Independent Dot Erase Level)

Filtering

•

SP4903-015 * (Pre Filter)

•

SP4903-055 to 056 * (MTF Filter Coefficient – Pale Originals)

Magnification

•

SP2909-001 (Main Scan Magnification)

ID Control

Gradation

•

SP4904-23 (Line Width Correction Type)

Auto Shading

Independent Dot Erase

MTF

Main Scan Magnification

γ Correction

Background Erase

Grayscale Processing/

Line Width Correction

Rev. 2/2000

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IMAGE PROCESSING

SM 2-25 A294/A295

Detailed

Descriptions

Generation Copy Mode

The image processing for generation mode is basically the same as in text mode, except that in order to prevent lines in the main scan direction from being reproduced too thickly, line width correction is applied for the final gradation treatment. Also, to reduce unwanted black dots, a weaker MTF filter is used; this ensures that isolated dots do not get bigger, and are spread out. These dots will then be deleted by the independent dot erase feature. This feature, however, is kept at a low setting to ensure that important details such as dotted lines and periods are not deleted.

Image Processing Path Related SP Modes

Input Correction 1

•

SP4903-069 * (Scanner Gamma Thresh Level)

•

SP4903-074 * (Background Erase Level)

Input Correction 2

•

SP4903-064 (Independent Dot Erase Level)

Filtering

•

SP4903-016 * (Pre Filter Coefficient)

•

SP4903-057 to 058 * (MTF Filter Coefficient – Generation Copy)

Magnification

•

SP2909-001 (Main Scan Magnification)

ID Control

Gradation

•

SP4903-75 to 77*, SP4904-24 (Line Width Correction Type)

Auto Shading

Background Erase

Independent Dot Erase

MTF

Main Scan Magnification

γ Correction

Grayscale Processing/

Line Width Correction

Rev. 2/2000

CÓPIA NÃO CONTROLADA

IMAGE PROCESSING

A294/A295 2-26 SM

2.3.5 AUTO SHADING

Two things happen during auto shading.

Black Level Correction

The black level is zeroed for each scan line of data by reading the dummy elements at the end of the CCD signal for each scan line, which should be black.

White Level Correction

The data is corrected for variations in white level across the main scan. To do this, a white reference plate is scanned before each original (book mode) or every 30 s (ADF mode). This corrects for the following effects on each pixel:

• Loss of brightness at the ends of the exposure lamp and the edges of the

lens

• Variations in sensitivity among the CCD elements

• Distortions in the light path

A294D645.WMF

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IMAGE PROCESSING

SM 2-27 A294/A295

Detailed

Descriptions

2.3.6 BACKGROUND ERASE

Background Erase

The background erase process is used only when setting of SP 4-903-70 to 74 is changed from the default setting (the default is ‘disabled’).

Usually, dirty background is erased using Auto Image Density (ADS). Background Erase should be used when ADS cannot fully erase the dirty background.

There are two Background Erase modes. The one that is being used depends on the SP mode setting. Setting 2 has a stronger effect than setting 1, but setting 2 may cause sudden changes in the data around the threshold level.

Setting 1: MTF correction is not applied to any low image density data that

remains after auto shading if the data is lower than a threshold level [A]. The overall effect is to reduce the background in a similar way to that shown by the dotted line in the diagram. This process can be applied for each image mode (except for photo mode) by changing the setting of SP4-903-70, 72, 73 or 74.

Setting 2: Any low image density data that remains after auto shading will be

treated as “0” if the data is lower than a threshold level [A]. The background is cut off as shown by the solid vertical line in the diagram at [A]. This process can be applied for each image mode by changing the setting of SP4-903-70, 71, 72, 73 or 74.

The thresholds can be changed with SP4-903-65 to 69.

255

Scanner Output

Scanner Input

[A] (Threshold)

A294D591.WMF

Rev. 2/2000

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IMAGE PROCESSING

A294/A295 2-28 SM

2.3.7 INDEPENDENT DOT ERASE

By default, this process is used in all image processing modes except for photo mode. This function allows independent black dots appearing on copies to be erased.

As shown in the drawing below, the software compares each pixel with the pixels in the surrounding 5 x 5 area (except for the immediately adjacent pixels).

If all of the surrounding pixels are white, and the difference between the value of the object pixels and the average of the surrounding pixel is larger than the threshold level, the object pixel is either changed to 0 (white) or reduced in density. The combination of the threshold value and the pixel data reduction ratio depends on the setting of SP4-903-60, 62, 63 or 64. If a larger number is selected, the effect of independent dot erase will be stronger. If 0 is selected, independent dot erase is disabled.

3030403020

40203040

2010

0 3070

20 300

Object pixel

Surrounding pixels to be used for calculation

Ignored pixels

A294D592.WMF

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IMAGE PROCESSING

SM 2-29 A294/A295

Detailed

Descriptions

2.3.8 FILTERING, MAIN SCAN MAGNIFICATION/REDUCTION

Overview

After auto shading, the image data is processed by both filtering and main scan magnification. However, to reduce the occurrence of moiré in the image, the processing order depends on the reproduction ratio, as follows.

1. 64% reduction or less

Main Scan Reduction → Filtering

2. 65% reduction or higher

Filtering → Main Scan Magnification

Filtering

By default, an individual MTF filter is used for each image processing mode, to enhance the desired image qualities. (For Photo mode, smoothing filter is selected as the default setting.)

A stronger MTF filter emphasizes sharpness and leads to better reproduction of low image density areas, but may leads to the occurrence of moiré in the image.

The MTF filter strength can be changed by changing the coefficient (MTF Filter Level) and strength of the MTF filter in combination using SP mode. Refer to the combination chart in ‘Image Quality Setting by UP Mode’ in section 4. The filter coefficient and strength can be adjusted in the main scan and sub scan directions individually. This allows the copy quality to be adjusted more precisely, to match the originals normally scanned by a particular customer.

Example: In a case when vertical lines (sub scan) are reproduced clearly, but

horizontal lines (main scan) are not reproduced clearly, the technician can adjust the main scan filter only.

For photo mode, the smoothing filter is the default filter, but the MTF filter may be selected by SP mode 4-903-9. This is effective when putting more weight on improving the resolution when copying from “continuous tone” originals.

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IMAGE PROCESSING

A294/A295 2-30 SM

Main Scan Magnification/Reduction

However, reduction and enlargement in the main scan direction are handled by the IPU chip on the SICU board.

Scanning and laser writing are done at a fixed pitch (the CCD elements cannot be squeezed or expanded). So, to reduce or enlarge an image, imaginary points are calculated that would correspond to a physical enlargement or reduction of the image. The correct image density is then calculated for each of the imaginary points based on the image data of the nearest four true points. The calculated image data then becomes the new (reduced or enlarged) image data.

Main scan magnification can be disabled with SP4-903-5 to test the IPU chip.

Sub Scan Magnification

When the selected magnification is 50% or larger, the image magnification in the sub scan direction is changed by changing the scanner speed. (As the magnification ratio increases, the scanner speed is reduced.)

However, when a magnification ratio smaller than 50% is selected, the required scanner speed exceeds the limit of the scanner motor. So, the scanner speed is reduced to half of the required speed for that reduction ratio. As a result, there are twice as many scan lines as needed. So alternate lines are removed.

For example, if a 49% magnification ratio is selected, the scanner speed is the same as the speed of 98% magnification, but the number of sub scan lines used for the image is half of that for 98% magnification.

A294D646.WMF

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IMAGE PROCESSING

SM 2-31 A294/A295

Detailed

Descriptions

2.3.9 GAMMA (γγγγ) CORRECTION

Gamma correction ensures accurate generation of the various shades in the gray scale from black to white, accounting for the characteristics of the scanner and printer.

Scanner gamma correction corrects the data output to the IPU to account for the characteristics of the scanner (e.g., CCD response, scanner optics).

Printer gamma correction corrects the data output from the IPU to the laser diode to account for the characteristics of the printer (e.g., the characteristics of the drum, laser diode, and lenses).

The scanner and printer gamma settings can be changed for the ‘Service Mode’ original type of text and text/photo modes, using SP4-903-84 and 85.

2.3.10 GRADATION PROCESSING

Various processes are available to try to reproduce various types of original as faithfully as possible.

The following processes are used in combination depending on the image mode settings.

1) Three-gradation processing

2) Four-gradation processing

3) Error diffusion

4) Dithering

These three processes are used as follows:

Text Mode: Error diffusion + line width correction and four-

gradation processing

Text/Photo Mode: Error diffusion + line width correction and four-

gradation processing

Photo Mode: Error diffusion or dithering, and three-gradation

processing

Generation Copy Mode: Error diffusion + line width correction, and three-

gradation processing

Pale Mode: Error diffusion and four-gradation processing

Three-gradation Processing

This mode is used in Photo mode.

The image density data after gamma correction is changed into three-gradation data (full dot, half dot, or blank) using two thresholds. With this processing, halftone images are reproduced smoother than with four-gradation processing because of stable dot image reproduction due to only one intermediate density level.

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IMAGE PROCESSING

A294/A295 2-32 SM

Four-gradation Processing

This process is used in Text mode and Text/Photo mode.

The image density data after gamma correction is changed into 2-bit data using 3 thresholds. The four gradations are reproduced by laser power control. This process is suitable for reproducing fine originals which do not include halftone areas.

Error Diffusion and Dithering

Error diffusion reduces the difference in contrast between light and dark areas of a halftone image. Each pixel is corrected using the difference between it and the surrounding pixels. The corrected pixels are then corrected using an error diffusion matrix.

With dithering, each pixel is compared with a pixel in a dither matrix. Several matrixes are available, to increase or decrease the detail on the copy.

Comparing with dithering, error diffusion gives a better resolution, and is more suitable for “continuous toned” originals. On the other hand, dithering is more suitable for “screen printed” originals.

In Photo mode, when the user selects “Normal Paper” or “Continuous Tone”, error diffusion is used. However, if the user selects “Screen Printed”, dither processing is used. If the user selects “SP Mode Changed”, then error diffusion or one of three types dither matrix can be selected with SP4-904-002. There are three types of dither matrix, 8" x 8", 6" x 6", and 4" x 4". A larger dither matrix causes halftone areas to become coarser.

2.3.11 LINE WIDTH CORRECTION

This function is effective for Text, Text/Photo and Generation modes.

The software compares each pixel with adjacent pixels. If the differences between the object pixel and adjacent pixels are more than a threshold, the software judges that the pixel is on a line edge, and line width correction is applied.

The line width correction setting can be changed separately for Text, Text/Photo and Generation modes. The widths of vertical and horizontal lines can be corrected separately.

• Thinner 1: If the pixel is on the edge of a line, its density is multiplied by 0.75

• Thinner 2: If the pixel is on the edge of a line its density is multiplied by 0.5

• Thicker: If the pixel is on the edge of a line, 48 is added to its density

The threshold for detecting edges of lines can also be changed separately for vertical lines and horizontal lines.

Use SP4-903-75 to 83 to adjust the line width correction settings.

Line width can also be corrected by adjusting the laser output (SP4904-20 to 24).

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LASER EXPOSURE

SM 2-33 A294/A295

Detailed

Descriptions

2.4 LASER EXPOSURE

2.4.1 OVERVIEW

This machine uses four laser diodes to produce electrostatic images on an OPC drum. The four parallel beams write four lines at once.

The laser diode unit converts image data from the SICU board into laser pulses, and the optical components direct these pulses to the drum.

Exposure of the drum by the laser beam creates the latent image. The laser beam makes the main scan while drum rotation controls the sub scan.

The strength of each beam is 10 mw on the drum surface at a wavelength of 785 nm.

The polygon motor speed is 29,528 rpm.

There are up to 4 image density levels for each pixel. To realize this, this machine uses a form of pulse width modulation. In this machine, pulse width modulation consists of the following processes:

• Laser diode pulse positioning

• Laser diode power/pulse width modulation

Laser diode power and pulse width modulation is done by the laser diode drive board (LDR). Briefly, the width of the laser pulse for a pixel depends on the output level (from 0 to 3) required for the pixel.

There are two fan motors, the polygonal motor cooling fan [A] and LDB cooling fan [B], for removing heat in the laser unit.

A294D103.WMF

[B]

[A]

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LASER EXPOSURE

A294/A295 2-34 SM

2.4.2 OPTICAL PATH

The output path from the laser diode to the drum is shown above.

The LD unit [A] outputs four laser beams to the polygonal mirror [B] (six mirror surfaces) through the cylindrical lens [C] and the 1st mirror [D].

Each surface of the polygon mirror reflects four full main scan lines. The laser beams go to the F-theta lens 1 [E], F-theta lens 2 [F], BTL (barrel toroidal lens) [G], and mirror [H]. Then these laser beams go to the drum through the toner shield glass [I].

The laser synchronizing detector [J] determines the main scan starting position. This board generates and sends a synchronization signal when the laser synchronization detector mirror [K] reflects the laser beam to the detector as the laser beam starts its sweep across the drum. The detector detects only the uppermost beam (channel 1) of the four.

A294D101.WMF

[A]

[J]

[K]

[I]

[H]

[F]

[G]

[E]

[C]

[D]

[B]

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LASER EXPOSURE

SM 2-35 A294/A295

Detailed

Descriptions

2.4.3 AUTO POWER CONTROL (APC)

There are four LD drivers (IC408, IC409, IC422 and IC423) on the LDB (Laser diode Drive Board). The LD drivers control the laser diodes on the 4-channel laser diode array. Even if a constant electric current is applied to the laser diode, the intensity of the output light changes with the temperature. The intensity of the output decreases as the temperature increases.

In order to keep the output level constant, IC410 and IC411 monitor the current passing through the photodiode (PD). Then they increase or decrease the current to the laser diode as necessary, comparing it with the reference levels (V

REF

). To apply APC separately to each laser diode using only one photo diode, the monitor current is sent in turn to each laser diode.

This auto power control is done just after the machine is turned on and during printing while the laser diode is active.

The reference levels are adjusted on the production line. Do not touch the variable resistors on the LDB in the field.

OUT

SENSE_IN

WRITE_LEVEL

OUT

SENSE_IN

WRITE_LEVEL

OUT

SENSE_IN

WRITE_LEVEL

OUT

SENSE_IN

REF

WRITE_LEVEL

REF

–

IC410

IC411

PD Charge

IC408

IC409

IC422

IC423

Analog SW

LDA

LDD

IC406

IC407

IC421

IC420

OUT

WR_PULSE

+ –

BGAVD

OUT

LVDS

Image Data

Clock

D/A Converter

LDB

A294D999.WMF

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LASER EXPOSURE

A294/A295 2-36 SM

2.4.4 FOUR BEAM LASER WRITING

This laser unit has four LD diodes for writing the image. This means that each surface of the polygonal mirror motor writes four main scan lines, and 24 main scan lines are produced when the polygonal mirror rotates once. Due to this multi beam writing, the polygonal mirror motor speed can be reduced, thus the noise generated by the polygonal mirror motor can be reduced.

The four laser beams are transferred to the polygonal mirror through a collimating lens. When the four laser beams arrive on the drum surface, the diameter of the

beam spot is 50 x 60 (main scan direction x sub scan direction) µm, and the distance between each pixel is approximately 42 µm. So the beam spots overlap

each other as shown above.

The laser diode array is assembled and adjusted in the factory, and no adjustment can be done in the field.

A294D102.WMF

ch1

ch2

ch3

ch4

Main Scan

Sub Scan

A294D500.WMF

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LASER EXPOSURE

SM 2-37 A294/A295

Detailed

Descriptions

2.4.5 LD SAFETY SWITCHES

To ensure technician and user safety and to prevent the laser beam from inadvertently switching on during servicing, there are four safety switches inside the front cover.

When one of the front covers is open, the 5 V line connecting to the LD drivers (LDD) is disconnected. The above diagram shows one LD and driver circuit as an example. There are four of these on the LDB board. Additionally, the OUT terminal of the PWM IC is automatically set at a low level to prevent any power from being supplied from the PWM IC to the LDD.

Even if 12 V is supplied from the op amp which controls the LD power level, the power will be less than the minimum power required for LD lighting (5 mA) due to

the 2.7 kΩ resistor.

LDD

LDA

+ –

LDB

WR_PULSE

WR_LEVEL

2.7k

PWM IC

21 2

OUT

PWR_REDUCE

+12V

–12V

CN404-1

CN404-3

CN403-2

CN401-27

CN403-1

CN403-3

–12V

+12V

+5V

Left and Right

Front Door

Safety Switches

A294D998.WMF

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DRUM UNIT

A294/A295 2-38 SM

2.5 DRUM UNIT

2.5.1 PROCESS CONTROL

Overview

The drum potential will gradually change because of the following factors.

• Dirty charge corona casing and grid plate

• Changes in drum sensitivity

To maintain good copy quality, the machine does the following just after the main

switch has been turned on (if the fusing temperature is less than 100 °C and SP3-

901 is on).

1) Potential Sensor Calibration

2) V

Adjustment

3) VG (Grid Voltage) Adjustment

4) LD Power Adjustment

5) V

REF

Update

This process is known as ‘Process Control Initial Setting’. The rest of this section will describe these steps in more detail.

Processes 1, 3, and 4 in the above list compensate for changes in drum potential. Processes 2 and 5 are for toner density control; see the “Toner Density Control” section for more details.

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DRUM UNIT

SM 2-39 A294/A295

Detailed

Descriptions

Drum Potential Sensor Calibration

The drum potential sensor [A] detects the electric potential of the drum surface [B].

Since the output of the sensor is affected by environmental conditions, such as temperature and humidity, the sensor needs recalibration at times. This is done during process control initial setting.

The charge/bias/grid power pack [C] has two relay contacts. Usually RA2 grounds the drum. However, to calibrate the sensor, the BCU switches RA2 and RA1 over, which applies the power pack output voltage to the drum shaft [D].

The machine automatically calibrates the drum potential sensor by measuring the output of the sensor when –200 V and –700 V are applied to the drum. From these two readings, the machine can determine the actual drum potential from the potential sensor output that is measured during operation. To prevent toner attraction to the drum during calibration, –200 V and –700 V are also applied to the development rollers.

During calibration, if the rate of change in drum potential sensor response to applied voltage is out of the target range, an SC310 or SC311 is logged and auto process control turns off. The VG and LD power adjustments are skipped; VG is set to the value stored in SP2-001-01, and LD power is set to the values stored in SP2-103.

VSG Adjustment

This calibrates the ID sensor output for a bare drum to 4.0 ± 0.2 V. It does this by

changing the intensity of the light shining on the drum from the sensor. This is done automatically during process control initial setting, and it can also be done manually with SP3-001-002.

If the ID sensor output cannot be adjusted to within the standard, an SC353 or 354 is logged and the light intensity is set to the previous accepted value.

–200/–700

RA2

RA1

[A]

[B]

[C]

[D]

CÓPIA NÃO CONTROLADA

DRUM UNIT

A294/A295 2-40 SM

VG Adjustment

The potential on unexposed areas of the drum (VD) gradually changes during drum life. To keep VD constant, the grid voltage (VG) is adjusted during process control initial setting.

The BCU checks VD using the drum potential sensor [A]. If it is not within the target

range (–900 V ± 20 V), the BCU adjusts V

(Grid Voltage) through the

charge/bias/grid power pack to get the correct target voltage.

The most recently detected values can be displayed with SP3-902-2 (VD) and 3902-4 (VG).

If the CPU cannot get VD within the target range by changing VG, VG is set to the value stored in SP2-001-01 and LD power is set to the value stored in SP2-103. Then SC312, SC313, or SC315 is logged.

Charge/Bias/Grid

P.P

BCU

A294D642.WMF

[A]

CÓPIA NÃO CONTROLADA

DRUM UNIT

SM 2-41 A294/A295

Detailed

Descriptions

LD Power Adjustment

This adjustment uses the drum potential sensor to keep the ID sensor pattern at the same density, so that V

REF

will be updated correctly (see the next page).

The VH pattern is developed using the current LD power (the density is the same as the ID sensor pattern). The drum potential sensor detects the potential on this pattern. The LD power is adjusted until V

becomes –265 V ± 20 V.

This is done only during process control initial setting.

The latest VH can be displayed using SP3-902-3. The size of the correction applied to the LD power can be displayed using SP3-902-5 (the default is stored in SP2103-1-4).

If VH cannot be adjusted to within the standard within 20 attempts, LD power is set to the latest value (the one used for the 20th attempt) and SC314 or SC316 is logged.

SICU

LDB

BCU

A294D643.WMF

CÓPIA NÃO CONTROLADA

DRUM UNIT

A294/A295 2-42 SM

REF

Update

The TD sensor reference voltage (V

REF

) is updated to stabilize the concentration of

toner in the development unit as follows;

New V

REF

= Current V

REF

+ ∆V

REF

∆V

REF

is determined using the following table.

VSP/V

∆∆∆∆V

REF

≤ 3/40

+0.08

≤ 9/100

+0.04

≤ 21/200

+0.00

≤ 1/8

–0.06

≤ 4/25

–0.12

≤ 41/200

–0.18

≤ 1/2

–0.24

> 1/2

Previous V

REF

When SC353 or SC354 is generated, V

REF

is not updated. The machine uses the

current value.

REF

is updated during process control initial setting. It is also updated at the end

of the copy job, if 10 or more copies have been made since the last V

REF

update. It

is not updated at the start of a job or at any time during a job.

CÓPIA NÃO CONTROLADA

DRUM UNIT

SM 2-43 A294/A295

Detailed

Descriptions

2.5.2 TONER DENSITY CONTROL

Overview

There are two modes for controlling toner supply: sensor control mode and image pixel count control mode. The mode can be selected with SP2-208. The factory setting is sensor control mode. Image pixel count mode should only be used if the TD or ID sensor is defective and cannot be replaced immediately.

Sensor Control Mode

Introduction

In sensor control mode, the machine varies toner supply for each copy to maintain the correct proportion of toner in the developer and to account for changes in drum reflectivity over time. The adjustment depends on two factors.

• Amount of toner needed to print the page (based on the black pixel amount for

the page).

• Readings from the TD sensor [A] and ID sensor [B].

Sensor control mode has two phases, called ‘ID sensor control’ and ‘TD sensor control. In ID sensor control, VSP/VSG from the most recent ID sensor pattern check determines the GAIN factor in the toner supply calculation (see later in this section). In TD sensor control mode, GAIN depends on the current TD sensor output also (VT – V

REF

is used).

TD Sensor

Output (V

)

ID Sensor Output

SP/VSG

)

GAINPixel Count

Toner Supply Clutch On Time

Calculation

REF

Update

TD Sensor Initial

Setting (V

REF

)

VT Reference

Voltage (V

REF

)

VT Reference

Voltage Update

(New V

REF

)

A294D644.WMF

[A]

[B]

CÓPIA NÃO CONTROLADA

DRUM UNIT

A294/A295 2-44 SM

The phase that is used depends on the number of copies since the start of the job. See the table below for details.

Number of copies in the job Copy no. Control method

10 or fewer 1 to 10 ID Sensor Control

First 10 ID Sensor Control

More than 10

From 11 TD Sensor Control

Toner Density Sensor Initial Setting

When new developer is installed, TD sensor initial setting must be done using SP2-801. This sets the sensor output to 2.5 V. This value will be used as the TD sensor reference voltage (V

REF

If the sensor output cannot be adjusted to within the standard, SC341 or SC342 is logged and the toner density control is set to the pixel count control.

VSP and VSG Detection

The ID sensor detects the following voltages.

• V

: The ID sensor output when checking the drum surface

• V

: The ID sensor output when checking the ID sensor pattern

In this way, the reflectivity of both the drum and the pattern on the drum are checked.

The ID sensor pattern is made on the drum with the charge corona and laser diode.

REF

Update

To update V

REF

(the TD sensor reference voltage), VSP/VSG is detected at the end

of the copy job, if 10 or more copies have been made since the last V

REF

update. This compensates for any variations in the reflectivity of the pattern on the drum or the reflectivity of the drum surface. The 10 copy interval can be changed using SP2-210.

REF

is also updated during process control initial setting.

If the reading of the ID sensor becomes abnormal while checking the ID sensor pattern, SC350, SC351, or SC352 is logged and the toner density control is done using TD sensor only.

See “V

REF

Update” in the Process Control section for more details.

CÓPIA NÃO CONTROLADA

DRUM UNIT

SM 2-45 A294/A295

Detailed

Descriptions

VT Detection

The toner density in the developer is detected once every copy cycle, after the trailing edge of the image passes the development roller.

If the reading from the TD sensor becomes abnormal during a copy job, the machine holds the GAIN factor constant to allow toner supply to vary with only the pixel count for the rest of the copy job. Then at the end of the job, SC340 is generated and the machine must be repaired.

If the TD sensor needs to be replaced and none is available, the toner supply mode can be set to image pixel count mode using SP2-208.

Image Pixel Count

For each copy, the CPU adds up the value of each pixel and converts the sum to a value between 0 and 255. (The value would be 255 if the page was all black.)

Gain Determination

GAIN is another factor in the toner supply clutch on time calculation. Its value can be 0, 1, 1.5, 2, 3, or 4. It is calculated either using VSP/VSG if ID sensor control is being used, or every copy using “VT – V

REF

” if TD sensor control is being used

(see Sensor Control Mode – Overview for more on TD and ID sensor control).

ID Sensor Control TD Sensor Control

VSP/V

GAIN

a = V

– V

REF

GAIN

≤ 3/40

a < 0.00

≤ 9/100

0.00 ≤ a < 0.02

≤ 21/200

0.02 ≤ a < 0.08

≤ 1/8

1.5

0.08 ≤ a < 0.14

≤ 4/25

0.14 ≤ a

≤ 41/200

≤ 1/2

> 1/2

Toner Supply Clutch On Time Calculation

The toner supply clutch on time for each copy is decided using the following formula: (GAIN x Image pixel count x 0.7mg/cm2/Toner Supply Rate) + 50 ms

When GAIN is “0”, the above 50 ms is set to “0”.

The toner supply rate can be changed using SP2-209.

Image Pixel Count Control

This mode should only be use as a temporary countermeasure while waiting for replacement parts, such as a TD sensor. This mode controls the toner supply using the same formula for the toner supply clutch on time. However, the GAIN value is fixed at 0.7.

CÓPIA NÃO CONTROLADA

DRUM UNIT

A294/A295 2-46 SM

2.5.3 DRUM UNIT COMPONENTS

The drum unit consists of the components shown in the above illustration. An organic photoconductor drum (diameter: 100 mm) is used for this model.

1. OPC Drum

2. Drum Potential Sensor

3. Pick-off Pawl

4. Image Density Sensor

5. Toner Collection Coil

6. Cleaning Brush

7. Cleaning Blade

8. Quenching Lamp

9. Charge Corona Unit

A294D201.WMF

CÓPIA NÃO CONTROLADA

DRUM UNIT

SM 2-47 A294/A295

Detailed

Descriptions

2.5.4 DRIVE

The drive from the drum motor [A] is transmitted to the drum and the cleaning unit through some timing belts, gears, the drum drive shaft [B], and the cleaning unit coupling [C].

The drum motor has a drive controller, which outputs a motor lock signal when the rotation speed is out of the specified range.

The fly-wheel [D] on the end of the drum drive shaft stabilizes the rotation speed.

A294D202.WMF

[C]

[A]

[D]

[B]

CÓPIA NÃO CONTROLADA

DRUM UNIT

A294/A295 2-48 SM

2.5.5 DRUM CHARGE

Overview

This copier uses a double corona wire scorotron system to charge the drum. Because of the high speed of this copier, two corona wires are needed to give a sufficient negative charge to the drum surface. The stainless steel grid plate makes the corona charge uniform and controls the amount of negative charge on the drum surface by applying a negative voltage to the grid.

The charge/bias/grid power pack [A] gives a constant corona current to the corona

wires (–1,200 µA).

The voltage to the grid plate is automatically controlled to maintain the correct image density in response to changes in drum potential caused by dirt on the grid plate and charge corona casing. This is described in the Process Control section in more detail.

A294D203.WMF

[A]

CÓPIA NÃO CONTROLADA

DRUM UNIT

SM 2-49 A294/A295

Detailed

Descriptions

Charge Corona Wire Cleaning

Air flowing around the charge corona wire may deposit toner particles on the corona wires. These particles may interfere with charging and cause low density bands on copies.

The wire cleaner pads [A] automatically clean the wires to prevent such a problem.

The wire cleaner is driven by a dc motor [B]. Normally the wire cleaner [C] is at the front end (this is the home position). Just after the main switch is turned on, the wire cleaner motor turns on to bring the wire cleaner to the rear and then back to the home position. When the wire cleaner moves from the rear to the home position (black arrow in the illustration), the wire cleaner pads clean the wires. Cleaning is done at auto process control, if 5,000 copies were made since the

wires were cleaned last, but only if the fusing temperature is less than 100°C.

A294D558.WMF

[A]

[B]

[C]

[A]

CÓPIA NÃO CONTROLADA

DRUM UNIT

A294/A295 2-50 SM

2.5.6 DRUM CLEANING

Overview

This copier uses a counter blade system to clean the drum. In a counter blade system, the drum cleaning blade [A] is angled against drum rotation. The counter blade system has the following advantages:

• Less wearing of the cleaning blade edge

• High cleaning efficiency

Due to the high efficiency of this cleaning system, the pre-cleaning corona and cleaning bias are not used for this copier.

The cleaning brush [B] helps the cleaning blade. The brush removes toner from the drum surface and any remaining toner is scraped off by the cleaning blade. Toner on the cleaning brush is scraped off by the mylar [C] and falls onto the toner collection coil [D]. The coil transports the toner to back to the toner entrance tank in the toner bank unit for recycling.

To remove any accumulated toner at the edge of the cleaning blade, the drum turns in reverse for about 4 mm [E] at the end of every copy job. The accumulated toner is deposited on the drum and is removed by the cleaning brush.

A294D204.WMF

A294D205.WMF

[A]

[B]

[A]

[B]

[D]

[C]

[B]

[A]

[E]

CÓPIA NÃO CONTROLADA

Gestetner A294, A295 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual