Ricoh FT6645 Manual 

Toner Supply Control: Fuzzy Control Photoconductor: OPC drum Originals: Sheet/Book Original Size: Maximum A3/11" x 17" Original Alignment: Left rear corner Copy Paper Size: Maximum A3/11" x 17" Minimum A5/51/2" x 81/2" (Tray) B5/81/2" x 11" (1.5K LCT) A6/51/2" x 81/2" (By-pass) Duplex Copying: Maximum A3/11" x 17" Minimum A5/51/2" x 81/2" (sideways) Copy Paper Weight: Paper tray: 52 ~ 128 g/m2, 14 ~ 34 lb Bypass feed table: 52 ~ 157 g/m2, 14 ~ 42 lb Duplex copying: 64 ~ 104 g/m2, 17 ~ 24 lb Reproduction Ratios: 4 Enlargement and 6 Reduction A4/A3 Version LT/LDG Version Enlargement 200% 141% 122% 115% 200% 155% 129% 121% Full Size 100% 100% Reduction 93% 82% 75% 71% 65% 50% 93% 85% 77% 74% 65% 50% Overall Information 23 April 1993 SPECIFICATIONS 1-1

220 ~ 240V, 50Hz/60Hz, more than 10A (for EU and AA) Power Consumption: A095 and A096 copiers Copier only Full system* Warm-up 0.9 kVA 0.9 kVA Stand-by 0.25 kVA 0.25 kVA Copying 1.2 kVA 1.3 kVA Maximum 1.45 kVA 1.5 kVA *Full System: • Mainframe with dual job feeder, compact sorter stapler and 3,500-sheet large capacity tray • Mainframe with dual job feeder, floor type sorter stapler and 3,500-sheet large capacity tray • Mainframe with recirculating document handler, finisher and 3,500-sheet large capacity tray Noise Emission: Copier only Full system* Copying 55 dB (A) 61 dB (A) Full System: • Mainframe with dual job feeder, compact sorter stapler and 3,500-sheet large capacity tray • Mainframe with dual job feeder, floor type sorter stapler and 3,500-sheet large capacity tray • Mainframe with recirculating document handler, finisher and 3,500-sheet large capacity tray Sound pressure level: The measurements are made according to ISO7779 SPECIFICATIONS 23 April 1993 1-2

1280 x 690 x 1020 (W x D x H Mainframe with copy tray, platen cover) Weight: Copier only: (Without the optional platen cover = Approximately 2 kg) A095 copier: Approximately 151 kg A096 copier: Approximately 163 kg Zoom: From 50% to 200% in 1% steps Copying Speed: A4/LT (sideways) A3/DLT B4/LG A095 copier 45 23 27 A096 copier 55 28 35 Warm-up Time: Less than 5 minutes (20°C) First Copy Time: 3.1 seconds (A4/81/2" x 11" sideways from the 1st feed station) Copy Number Input: Number keys, 1 to 999 (count up or count down) Manual Image Density Selection: 7 steps Automatic Reset: 1 minute standard setting; can also be set from 1 second to 999 seconds or no auto reset. Copy Paper Capacity: • By-pass feed table: approximately 50 sheets • Paper tray: approximately 550 sheets • Tandem tray: approximately 500 sheets • Large capacity tray: approximately 1500 sheets Overall Information 23 April 1993 SPECIFICATIONS 1-3

• Recirculating document handler • 20 bin sorter stapler (Floor type) • 20 bin compact sorter stapler • Finisher • 3500-sheet Large capacity tray • Receiving Tray SPECIFICATIONS 23 April 1993 1-4

2.1 COPIER OVERVIEW There are two types of mainframe. A095 copier A096 copier 550 550 550 (3,500) (3,500) 500 x 2 or 500 550 1,500 Overall Information 23 April 1993 MACHINE CONFIGURATION 1-5

System A (The mainframe (A095) with dual job feeder and compact sorter stapler) System B (Mainframe type (A095/A096) with dual job feeder and floor type sorter stapler. The mainframe in the illustration below is the A096.) Compact sorter stapler (A374) Dual job feeder (A376) 3,500-sheets large capacity tray (A380) Dual job feeder (A376) 3,500-sheets large capacity tray (A380) Floor type sorter stapler (A377) MACHINE CONFIGURATION 23 April 1993 1-6

3,500-sheets large capacity tray (A380) Recirculating document handler (A378) Finisher (A379) Overall Information 23 April 1993 MACHINE CONFIGURATION 1-7

1. OPC DRUM The organic photo conductive (OPC) drum (100 mm diameter) has high resistance in the dark and low resistance under light. 2. DRUM CHARGE In the dark, the charge corona unit gives a uniform negative charge to the OPC drum. The charge remains on the surface of the drum. The amount of negative charge on the drum is proportional to the negative grid bias voltage applied to the grid plate on the charge corona unit. 3. EXPOSURE An image of the original is reflected to the OPC drum surface via the optics section. The charge on the drum surface is dissipated in direct proportion to the intensity of the reflected light, thus producing an electrical latent image on the drum surface. The amount of charge remaining as a latent image on the drum depends on the exposure lamp intensity controlled by the exposure lamp voltage. 4. ERASE The erase lamp illuminates the areas of the charged drum surface that will not be used for the copy image. The resistance of drum in the illuminated areas drops and the charge on those areas dissipates. 10 9 8 7 6 5 4 3 1 2 11 COPY PROCESS AROUND THE DRUM 23 April 1993 1-8

The drum potential sensor detects the electric potential on the drum to compensate image processing elements. 6. DEVELOPMENT Positively charged toner is attracted to the negatively charged areas of the drum, thus developing the latent image. (The positive triboelectric charge of the toner is caused by friction between the carrier and toner particles.) The development bias voltage applied to the development roller shaft controls two things: 1) The threshold level if toner is attracted to the drum or toner remains on the development roller. 2) The amount of toner to be attracted to the drum. The higher the negative development bias voltage is, the less toner is attracted to the drum surface. 7. PRE-TRANSFER LAMP (PTL) The PTL illuminates the drum to remove almost all the negative charge from the exposed areas of the drum. This makes image transfer easier. 8. IMAGE TRANSFER Paper is fed to the drum surface at the proper timing so as to align the copy paper and the developed image on the drum surface. Then, a negative charge is applied to the reverse side of the copy paper by the transfer belt, producing an electrical force which pulls the toner particles from the drum surface onto the copy paper. At the same time, the copy paper is electrically attracted to the transfer belt. 9. PAPER SEPARATION Paper separates from the OPC drum by the electrical attraction between the paper and the transfer belt. The pick-off pawls help to separate the paper from the drum. 10. CLEANING The cleaning brush removes toner remaining on the drum after image transfer and the cleaning blade scrapes off all the remaining toner. 11. QUENCHING Light from the quenching lamp electrically neutralizes the charge potential of the drum surface. Overall Information 23 April 1993 COPY PROCESS AROUND THE DRUM 1-9

2 3 4 5 11 10 12 7 6 29 26 35 34 25 24 31 30 16 32 33 15 14 13 27 19 18 23 22 21 17 20 28 8 9 1 39 38 37 36 MECHANICAL COMPONENT LAYOUT 23 April 1993 1-10

2. 2nd Mirror 3. 1st Mirror 4. Exposure Lamp 5. Lens 6. Cleaning Brush 7. Cleaning Blade 8. Quenching Lamp 9. Charge Corona Unit 10. OPC Drum 11. 6th Mirror 12. 4th Mirror 13. 5th Mirror 14. Erase Unit 15. Drum Potential Sensor 16. Toner Hopper 17. Development Unit 18. Pre-Transfer Lamp 19. Pick-up Roller 20. Feed Roller 21. Separation Roller 22. Registration Rollers 23. Transfer Belt 24. Vertical Transport Rollers 25. Tandem Tray (A096 copier) 550-sheet Tray (A095 copier) 26. Universal Tray 27. 1500-sheet LCT (A096 copier) 550-sheet Tray (A095 copier) 28. Toner Collection Bottle 29. Transfer Belt Cleaning Blade 30. Hot Roller 31. Pressure Roller 32. Jogger Fences 33. Duplex Positioning Roller 34. Duplex Pick-up Roller 35. Duplex Feed Roller 36. Separation Belt 37. Junction Gate 38. Exit Rollers 39. Optics Cooling Fan Overall Information 23 April 1993 MECHANICAL COMPONENT LAYOUT 1-11

8 † ‡ ˆ ‰ Š 1 10 11 ƒ 9 2 3 4 5 6 7 ‚ „ ‚ Main Motor ƒ Scanner Drive Motor „ Fusing/Duplex Drive Motor … Paper Feed Motor † Toner Collection Motor ‡ Registration Clutch ˆ By-Pass Feed Motor ‰ BY-Pass Feed Clutch Š Development Drive Motor 1. OPC Drum 2. Scanner Unit 3. Transfer Belt Unit 4. Paper Exit Unit 5. Fusing Unit 6. Duplex Unit 7. Paper Trays 8. Paper Feed Units 9. Toner Hopper 10. Development Unit 11. Cleaning Unit DRIVE LAYOUT 23 April 1993 1-12

6.1 STANDARD COPYING Paper feed begins from the exterior LCT, by-pass feed table or paper feed stations in the paper tray unit. The copy paper then follows one of two paths inside the copier. The path followed depends on which mode the operator has selected. For copy processing, all sheets follow the same paths from the paper feed mechanism [A] through the registration rollers [B], transfer belt [C], and fusing unit [D]. After that, copies are delivered to the sorter bins [E] or proof tray [F], however, 2 sided copies are diverted for further processing. [D] [C] [B] [A] [A] [F] [E] Overall Information 23 April 1993 PAPER PATH 1-13

In this mode the junction gate [A] directs sheets exiting the fusing unit to the duplex tray entrance. After that, all sheets follow the path through the duplex entrance rollers [B]. After all front side copying is completed, the sheets on the duplex tray are fed in order from the bottom to the top and follow the path through the duplex feed mechanism and vertical transport rollers [C] to the registration rollers [D]. After that, these sheets follow the same path as standard copying from the registration rollers to the sorter. a. Front Side [A] [B] [D] [C] b. Rear Side PAPER PATH 23 April 1993 1-14

Refer to the electrical component layout on the reverse side of the attached Point to Point for symbols and index numbers. Symbol Name Function Index No. Motors M 1 Scanner Drive Drives the 1st and 2nd scanners (dc servo). 42 M 2 Exhaust Fan Removes the heat from around the fusing unit. 43 M 3 Main Drives the main unit components. 44 M 4 Development Drive Drives the development unit. 45 M 5 By-pass Feed Drives the by-pass feed rollers. 46 M 6 3rd Scanner Drive Drives the 3rd scanner (dc stepper) 47 M 7 Toner Bottle Drive Rotates the toner bottle to supply toner to the toner hopper. 48 M 8 Charge Wire Cleaner Drive Drives the main charge wire cleaner to clean the charge wire. 49 M 9 Jogger Drives the jogger fences to square the paper stack in the duplex tray (dc stepper). 50 M10 Lens Horizontal Drive Shifts the lens horizontal position. 51 M11 Lens Vertical Drive Shifts the lens vertical position. 52 M12 Optic Cooling Fan Removes heat from the optics unit. 53 M13 Fusing/Duplex Drive Drives the fusing unit, the duplex unit, and the paper exit rollers. 54 M14 Paper Feed Drives all feed and transport rollers in the paper tray unit. 90 M15 1st Lift Raises the bottom plate in the 1st paper tray. 91 M16 2nd Lift Raises the bottom plate in the 2nd paper tray. 92 M17 Toner Collection Transports the collected toner to the toner collection bottle. 93 Overall Information 23 April 1993 ELECTRICAL COMPONENT DESCRIPTION 1-15

Raises the bottom plate in the 3rd paper tray. 94 M19 Side Fence Drive (A096 copier only) Opens and closes the front and the rear side fences of the tandem tray. 95 M20 Rear Fence Drive (A096 copier only) Moves the papers stacked in the left tandem tray to the right tandem tray. 96 M21 LCT Motor (A096 copier only) Lifts and lowers the LCT bottom plate to bring paper to the feed position and allow loading of the paper. 127 Magnetic Clutches MC1 Toner Supply Turns the toner supply roller to supply toner to the development unit. 57 MC2 Registration Drives the registration rollers. 58 MC3 By-pass Feed Starts paper feed from the by-pass feed table. 60 MC4 Duplex Transport Drives the duplex transport rollers to transport the paper to the vertical transport rollers. 64 MC5 Duplex Feed Starts paper feed from the duplex tray to the duplex transport rollers. 65 MC6 1st Feed Starts paper feed from the 1st feed tray. 99 MC7 2nd Feed Starts paper feed from the 2nd feed tray. 101 MC8 3rd Feed Starts paper feed from the 3rd feed tray. 104 ELECTRICAL COMPONENT DESCRIPTION 23 April 1993 1-16

is open or closed. 25 SW2 Front Door Safety Cuts the ac power line and detects if the front door is open or not. 29 SW3 1st Tray Set (A095 copier only) Detects if the 1st tray is set or not. 66 SW4 2nd Paper Size Determines what size paper is in the 2nd (universal) paper tray. 67 SW5 Toner Overflow Detects when the toner collection bottle is full. 75 SW6 Toner Collection Bottle Set Detects if the toner collection bottle is set or not. 77 SW7 Lower Front Door Safety Detects if the front door is open or not. 83 SW8 3rd Tray Set (A095 copier only) Detects if the 3rd tray is set or not. 84 SW9 Main Provides power to the copier 122 SW10 Tray Down (A096 copier only) Lowers the LCT bottom plate. 126 Solenoids SOL 1 Junction Gate Moves the junction gate to direct copies to the duplex tray or to the paper exit. 55 SOL 2 Duplex Positioning Controls the up-down movement of the positioning roller. 56 SOL 3 By-pass Pick-up Controls the up-down movement of the pick-up roller for by-pass feed. 59 SOL 4 Guide Plate Opens the guide plate when a paper misfeed occurs around this area. 61 SOL 5 Transfer Belt Positioning Controls the up-down movement of the transfer belt unit. 62 Overall Information 23 April 1993 ELECTRICAL COMPONENT DESCRIPTION 1-17

tray against the duplex feed rollers. 63 SOL 7 Tandem Lock Locks the left tandem feed tray and separates the right and left tandem trays. 97 SOL 8 1st Pick-up Controls the up-down movement of the pick-up roller in the 1st feed station. 98 SOL 9 1st Separation Roller Controls the up-down movement of the separation roller in the 1st feed station. 100 SOL10 2nd Pick-up Controls the up-down movement of the pick-up roller in the 2nd feed station. 102 SOL11 2nd Separation Roller Controls the up-down movement of the separation roller in the 2nd feed station. 103 SOL12 3rd Pick-up Controls the up-down movement of the pick-up roller in the 3rd feed station. 105 SOL13 3rd Separation Roller Controls the up-down movement of the separation roller in the 3rd feed station. 106 Sensors S 1 Scanner HP Informs the CPU when the 1st and 2nd scanners are at the home position. 1 S 2 Platen Cover Position–1 Informs the CPU that the platen cover is in the up or down position (related to APS/ARE function). 2 S 3 Platen Cover Position–2 Informs the CPU that the platen cover is in the up or down position to detect if the original has been removed or not. 3 ELECTRICAL COMPONENT DESCRIPTION 23 April 1993 1-18

Informs the CPU that the lens is at the full-size position. 4 S 5 Lens Horizontal HP Informs the CPU that the lens is at the horizontal home position. 5 S 6 3rd Scanner HP Informs the CPU when the 3rd scanner is at the home position. 6 S 7 By-Pass Paper End Informs the CPU that there is no paper in the by-pass feed table. 7 S 8 Guide Plate Position Informs the CPU if the registration guide plate is closed or not. 8 S 9 Jogger HP Detects if the duplex jogger fences are at the home position or not. 9 S10 Vertical Transport Detects the leading edge of the paper to determine the paper feed timing of the next sheet. 10 S11 Duplex Exit Detects the leading edge of the paper to determine the duplex transport clutch on timing. 11 S12 Duplex Entrance Sensor Detects the leading edge of the paper to determine the duplex feed clutch off timing. 12 S13 Duplex Paper End Detects paper in the duplex tray. 13 S14 Duplex Transport Detects the leading edge of the paper to control the jogger motor and the positioning solenoid on timing. 14 S15 Exit Detects misfeeds. 15 S16 Fusing Exit Detects misfeeds. 16 S17 Paper Guide Detects misfeeds. 17 S18 Auto Image Density Senses the background density of the original. 20 S19 Original Length–1 Detects original length. 21 S20 Original Length–2 Detects original length. 22 S21 Original Width Detects original width. 23 Overall Information 23 April 1993 ELECTRICAL COMPONENT DESCRIPTION 1-19

Informs the CPU what size paper is in the by-pass feed table. 26 S23 Toner Density Senses the amount of toner in the black developer. 27 S24 Registration Detects misfeeds and controls registration clutch off-on timing. 28 S25 Toner End Detects toner end condition. 30 S26 Auto-Response Returns the display from the screen saver. 34 S27 Drum Potential Detects the drum surface potential. 39 S28 Image Density Detects the density of the ID sensor pattern on the drum. 41 S29 1st Paper End Informs the CPU when the 1st cassette runs out of paper. 68 S30 1st Paper Near End Informs the CPU when the 1st cassette is in near end condition. 69 S31 1st Paper Feed Controls the 1st paper feed clutch off/on timing and the 1st pick-up solenoid off timing. 70 S32 2nd Paper Near End Informs the CPU when the 2nd cassette is in near end condition. 71 S33 1st Lift Detects the correct feed height of the 1st cassette. 72 S34 2nd Paper End Informs the CPU when the 2nd cassette runs out of paper. 73 S35 Toner Collection Motor Detects the toner collection motor operation. 74 S36 2nd Lift Detects the correct feed height of the 2nd cassette. 76 S37 3rd Lift Detects the correct feed height of the 3rd cassette. 78 S38 3rd Paper Near End (A095 copier only) Informs the CPU when the 3rd cassette is in near end condition. 79 S39 3rd Paper End Informs the CPU when the 3rd cassette runs out of paper. 80 ELECTRICAL COMPONENT DESCRIPTION 23 April 1993 1-20

Controls the 3rd paper feed clutch off/on timing and the 3rd pick-up solenoid off timing. 81 S41 2nd Paper Feed Controls the 2nd paper feed clutch off/on timing and the 2nd pick-up solenoid off timing. 82 S42 Base Plate Down (A096 copier only) Detects when the bottom plate is completely lowered to stop the 1st lift motor. 85 S43 Side Fence Positioning (A096 copier only) Informs the CPU when the tandem tray side fences are open. 86 S44 Rear Fence Return (A096 copier only) Informs the CPU when the tandem tray rear fence is in the return position. 87 S45 Rear Fence HP (A096 copier only) Informs the CPU when the tandem tray rear fence is in the home position. 88 S46 Left Tandem Paper End (A096 copier only) Informs the CPU when the left tandem tray runs out of paper. 89 S47 LCT Near End (A096 copier only) Detects the paper near end condition. 123 S48 Tray Down (A096 copier only) Detects when the tray is completely lowered to stop the LCT motor. 124 S49 Tray Paper Set (A096 copier only) Informs the CPU when the paper is set on the LCT bottom tray. 125 PCBs PCB 1 AC Drive Provides AC power to the exposure lamp and fusing lamp. 108 PCB 2 Main Controls all machine functions. 109 PCB 3 Optic Control Controls all optics components. 110 PCB 4 High Voltage Control Controls the output of both power packs and development bias. 111 Overall Information 23 April 1993 ELECTRICAL COMPONENT DESCRIPTION 1-21

Controls all components in the paper bank. 112 PCB 6 DC Power Supply Unit Provides DC power. 113 PCB 7 Guidance Controls the guidance display. 120 PCB 8 Operation Panel Controls the LED matrix, and monitors the key matrix. 121 Lamps L1 Exposure Applies high intensity light to the original for exposure. 18 L2 Fusing Provides heat to the hot roller. 32 L3 Quenching Neutralizes any charge remaining on the drum surface after cleaning. 37 L4 Erase Discharges the drum outside the image area. 38 L5 Pre-transfer Reduces the charge on the drum surface before transfer. 40 Power Packs PP1 Transfer Provides high voltage for the transfer belt and controls the transfer belt positioning solenoid. 117 PP2 Charge Provides high voltage for the charge corona wires, and the grid plate. Controls QL, PTL, and charge wire cleaner motor functions. 119 Others TS1 Optics Thermoswitch Opens the exposure lamp circuit if the optics unit overheats. 19 TF1 Fusing Thermofuse Opens the fusing lamp circuit if the fusing unit overheats. 33 TH1 Fusing Thermistor Senses the temperature of the hot roller. 24 ELECTRICAL COMPONENT DESCRIPTION 23 April 1993 1-22

optics cavity. 36 TH3 Drum Thermistor (Located on the ID Sensor Ass’y) Monitors the temperature of the OPC drum. 41 H1 Transfer Anti-Condensation Turns on when the main switch is off to prevent moisture from forming on the transfer belt. 31 H2 Optics Anti-Condensation Turns on when the main switch is off to prevent moisture from forming on the optics. 35 RA1 Main Power Relay Controls main power. 107 CO1 Total Counter Keeps track of the total number of copies made. 114 NF1 Noise Filter Removes electrical noise. 115 CB1 Circuit Breaker Provides back-up high current protection for the electrical components. 116 LA1 Lightening Arrestor Removes current surges from the AC input lines. 118 Overall Information 23 April 1993 ELECTRICAL COMPONENT DESCRIPTION 1-23

1.1 OVERVIEW This model uses two process control methods. One compensates for variation in the drum potential (latent image control) and the other controls the toner concentration and toner supply amount (image density control). Temperature Sensor ID Sensor Lamp Voltage Grid Voltage QL VD Pattern VD Pattern VL Pattern VL Pattern Erase Lamp Drum Potential Sensor Original Exposure Glass Original Scale ADS Pattern Toner Supply On time Development. Bias TD Sensor Toner Supply Control Image Density Control (Fuzzy Control) Main PCB Paper Latent image Control Exposure Control Charge Control Latent Image Control Image Density Control (Fuzzy Control) Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-1

The figure shows the changes of the drum potential during the copy process. Vo: The drum potential just after charging the drum. VD (Dark Potential): The drum potential just after exposing the black pattern (VD pattern) VL (Light Potential): The drum potential just after exposing the white pattern (VL pattern) VR (Residual Voltage): The drum potential just after the exposure of the erase lamp. After long usage following installation or a PM, drum potential will gradually increase due to the following factors: Dirty optics or exposure lamp deterioration Dirty charge corona wire and grid plate Change of the drum sensitivity In this copier, the change in drum potential is detected by the drum potential sensor and the following items are controlled to maintain good copy quality. The grid bias voltage The exposure lamp voltage The development bias voltage. A drum thermistor detects the drum temperature and this data is also used to control the above voltages. It is impossible to explain simply because it is controlled by methods developed in our laboratories using an artificial neural network. QL Charge Vo Exposure Black White Erase Potential Sensor Drum VD VL VR PROCESS CONTROL 23 April 1993 2-2

Image density is controlled by the following sensors: Toner density sensor (TD sensor) Image density sensor (ID sensor) Data from the TD sensor is used to keep the toner concentration in the developer at a constant level. However, the image on the OPC drum varies due to the variation of toner chargeability (influenced by the environment) even if the toner concentration is constant. By the ID sensor compensation, toner concentration is changed to keep the image density on the OPC drum constant. The following items are controlled to maintain a constant copy image density: Toner supply clutch on time Toner supply level data (VREF) of the TD sensor Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-3

The following flow chart shows all the steps that will be performed whenever the machine is turned on while the hot roller temperature is below 100°C. This initializes all the process control settings. Main SW On (Fusing Temp. < 100°C) Charge wire cleaning (if more than 5 K copies are made since last cleaning Drum Potential Sensor Calibration Drum Conditioning Start (Fusing Temp. = 180°C) VSG Adjustment VR Measurement VD/VL Correction TD Sensor Detection ID Sensor Detection/Correction ADS Adjustment x : See Latent Image Control section (Page 2-5) for details. y : See Image Density Control section (Page 2-12) for details. z: See Optics section (Page 2-39) for details. x y z PROCESS CONTROL 23 April 1993 2-4

1.3.1 Drum Potential Sensor Calibration The drum potential sensor [A] is located just above the development unit. The sensor has a detector which detects the strength of the electric field from the electric potential on the drum. The output of the sensor depends on the strength of the electric field. Since the output of the sensor is affected by environmental conditions, such as temperature and humidity, the sensor output is calibrated during process control data initial setting. The High Voltage Control PCB [B] has two relay contacts. Usually RA602 grounds the drum. However, during the initial setting, the main PCB turns RA601 on and RA602 off and applies the voltage to the drum shaft. By measuring the output of the drum potential sensor when –100 V and –800 V are applied to the drum, the sensor output is calibrated automatically. (The machine recognizes the relationship between actual drum potential and the potential sensor output.) Drum Case Sensor Output Amp. RA601 RA602 -100 V -800 V [A] Main PCB [B] Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-5

When the fusing temperature reaches 180°C, the machine starts the drum conditioning process. In this mode, the main motor, main charge corona, erase lamp and development bias are activated for about 30 seconds and drum sensitivity and residual voltage (VR) are stabilized, as in continuous copy runs. 1.3.3 VSG Adjustment During drum conditioning, the ID sensor checks the bare drum’s reflectivity and calibrates the output of the ID sensor to 4 ±0.2 V. 1.3.4 VR Measurement The above figure shows the relationship between the drum potential and the original density. To get constant copy quality, this relationship must be maintained. Since this relationship tends to change to the one represented by the dotted line by various factors, compensations are required. The residual voltage (VR) cannot be compensated even if the exposure lamp voltage is increased. Therefore, the VR change has to be compensated by other means. The main control board checks the drum potential just after the erase lamp exposure by the drum potential sensor after drum conditioning. This measured drum potential is in fact VR. This VR is used as the standard for the VD and VL corrections. NOTE: In the figure above, the residual voltage (VR) for the new drum is 0V. Actually, there is some residual voltage even on the new drum. [V] Vo VD VL VR Drum Potential Light Original Density Dark New Drum Used Drum [–V] PROCESS CONTROL 23 April 1993 2-6

The drum potential just after the black pattern (VD Pattern) is exposed (VD: Dark Potential) tends to lower during drum life due to a decrease in the drum’s capacity to carry a charge. To check the actual VD, the first scanner moves to the home position and the VD pattern (Black) stuck on the bottom side of the exposure glass bracket is exposed on the drum. The main control board measures VD through the drum potential sensor and adjusts it to a target value by adjusting the grid bias voltage (VGRID). On the other hand, there is a change of the drum residual voltage (VR), so that the target VD voltage is compensated as follows: Target VD Value: VD = VR + (–770) The adjusted grid bias voltage (VGRID) is kept in memory until the next process control data initial setting. [-V] VD –770 VR VR Drum Potential Dark Light Original Density VD Compensated After many copies New Drum Exposure Glass VD Pattern Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-7

Dirty optics and/or exposure lamp deterioration decreases the intensity of the light that reaches the drum. In addition to this, the drum sensitivity also changes during the drum’s life. These factors change the drum potential just after white pattern exposure (VL: Light Potential). To check the actual VL, the first scanner moves under the VL pattern (White) stuck underneath the original scale. The pattern is exposed on the drum. The main control board measures VL through the drum potential sensor and adjusts it to a target value by adjusting the exposure lamp voltage (VLAMP). The residual voltage (VR) change also affects VL, so that VL’s target voltage is compensated as follows: Target VL Value: VL = VR + (–140) The adjusted exposure lamp voltage (VLAMP) is stored in memory until the next process control data initial setting. Exposure Glass VL Pattern [-V] –770 VR VR VR –140 VD Only VD Compensated VD and VL Compensated New Drum Dark Light Original Density Drum Potential VL PROCESS CONTROL 23 April 1993 2-8

Potentials (VR, VD, VL) are monitored by the potential sensor. (This is done only when the fusing temperature is less than 100°C after the machine is turned on.) During the check cycle, the VD and VL patterns are exposed and the drum potential on the area where exposed by each pattern is checked by the potential sensor. Compare the curve of the VD and VL compensated drum potential with the curve of the new drum, they are parallel but the compensated potential is still higher (VR) than the new drum potential. To prevent dirty backgrounds due to increased residual potential, development bias (VBB) is applied as follows: VBB= VR + (–220) [-V] VR VD VL VR New Drum VD and VL Compensated Development Bias (VBB) Dark Light Original Density Drum Potential VR –770 –140 Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-9

The following graph shows the sequence of events during process control data initial setting. 1. Potential sensor calibration By measuring the output of the drum potential sensor when –100 V and –800 V are applied to the drum, the sensor output (V100 and V800) is calibrated automatically (See page 2-5 for details). 2. VR, VD, VL potential detection After about 30 seconds of drum conditioning, VD and VL Patterns are developed by using the previous grid bias voltage (VGRID) data and exposure lamp voltage (VLAMP) data to detect the VR, VD, VL data. The machine calculates the new VGRID and VLAMP data using the detected VR, VD, VL data. 1. Potential sensor calibration 2. VR’, VD’, VL’ potential detection 4. ID sensor pattern potential detection 3. VD, VL correction V800 V100 VD New VD New VL New VR VL VR Scanner Motor Exposure Lamp forward reverse for the purpose of ADS sensor correction Latent Image Control Potential Sensor Output PROCESS CONTROL 23 April 1993 2-10

Using the calculated VGRID and VLAMP data, VR, VD, and VL patterns are developed again and the new VR, VD, and VL data are detected. If both VD and VL data are within specifications, the new VGRID, VLAMP and development bias (VBB) are determined based on the new VD, VL, and VR values. Specifications: VD = –770 + VR ± 20 V VL = –140 + VR ± 20 V If VD is outside specifications, VGRID is shifted one step. Then the VD pattern is measured again and VD is detected again. The same is done for VL and VLAMP. The above process continues until both VD and VL fall within specifications. The graph on the previous page shows the example when only VL was outside specifications at the first VL detection and it became within specifications after one VL correction (VLAMP is changed 0.5V/step , VGRID is changed 20V/step). If V100 or V800 at drum potential sensor calibration is outside specifications or if VD or VL do not fall within specifications after VGRID or VLAMP are shifted to the maximum or minimum level, the machine stops VD or VL correction and uses the previous VGRID and VLAMP values during copying. In this case, nothing is indicated on the machine but the SC counter is incremented. Related SC codes (see troubleshooting section for details): Code Condition 361 Incomplete drum potential sensor calibration 364 Abnormal VD detection 365 Abnormal VL detection Development bias is also decided by using VR as follows. VBB = VR + (–220) 4. ID sensor pattern potential detection This is performed to determine ID Sensor Bias Voltage. The details are explained in the development control section (see page 2-16). Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-11

1.4.1 Toner Density Sensor Developer consists of carrier particles (iron) and toner particles (resin and carbon). Inside the development unit, developer passes through a magnetic field created by coils inside the toner density sensor. When the toner concentration changes, the voltage output by the sensor changes accordingly. When new developer with the standard toner concentration (2.0% by weight, 20 g of toner in 1000 g of developer) is installed, developer initial setting must be performed by using SP mode ( SP Adjustment – PAGE 1). During this setting, the output voltage (VOUT) from the auto gain control circuit (AGC) on the main control board PCB varies to change the output voltage from the toner density (TD) sensor. This is done by changing the gain data, see below. VOUT = VIN x Gain Data 256 = 12 x Gain Data 256 If the data is high, VOUT becomes high, and the sensor output voltage becomes high. As a result, the sensor characteristic becomes as illustrated by curve A. If the data is low, VOUT becomes low, and the sensor output voltage becomes low. As a result, the sensor characteristic shifts as illustrated by curve C. 1 1 2 3 4 5 0 1 2 3 4 New Developer C B A V Toner Weight % Sensor Output (V) REF A: VOUT (Gain data) is high. B: VOUT is within the specification. C: VOUT (Gain data) is low. Main PCB VIN VOUT AGC TD Sensor VD (12 V) GND Sensor Output VOUT = VIN x Gain 256 = 12 x Gain 256 PROCESS CONTROL 23 April 1993 2-12

control level (VREF, VREF = 2.5 ± 0.1 V). Now, the sensor characteristic is illustrated by curve B and the TD sensor initial setting is completed. The selected gain data is stored in memory, and VOUT from the auto gain control circuit stays constant during the toner sensor detection cycle. At every copy cycle, toner density in the developer is detected once. The sensor output voltage (VTD) during the detection cycle is compared with the toner supply level voltage (VREF). Toner Weight % Sensor Output (V) 1 2 3 4 5 0 1 2 3 4 5 V VREF TD Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-13

To stabilize toner concentration, toner supply amount (toner supply clutch on time) is controlled by referring to VREF and VTD. The toner supply amount is calculated at every copy. The toner supply amount is determined by using the following factors. x VREF – VTD y VREF – VTD’ (VTD’ = VTD of the previous copy cycle) By referring to these factors, the machine recognizes the difference between the current toner concentration and the target toner concentration. The machine also understands how much toner concentration has changed and predicts how much the toner supply amount will probably change. By changing the toner supply amount precisely, toner concentration (image density) is kept at a constant level. Since the toner supply clutch on time updating is under fuzzy control, the relation among VTD, VTD’, VREF cannot be expressed by a simple algebraic formula. The image on the OPC drum changes due to variation of toner chargeability (influenced by the environment) even if the toner concentration is constant. The image density sensor (ID sensor) directly checks the image on the OPC drum and shifts VREF data (under fuzzy control) to keep the image on the OPC drum constant, as explained in the next section. NOTE: 1. Toner end condition is detected by the toner end sensor (see the development section for details). 2. The toner supply clutch turns on at the intervals between each copy process while image development is not performed. Previous Copy Last Copy Next Copy VREF VTD’ VTD PROCESS CONTROL 23 April 1993 2-14

VSG and VSP are checked by the ID sensor [A]. The ID sensor is located underneath the drum cleaning section. There is no ID sensor pattern in the optics, however, a pattern image is made on the OPC drum by the charge corona unit [B] and the erase lamp [C]. VSG is the ID sensor output when checking the erased drum surface. VSP is the ID sensor output when checking the ID sensor pattern image. To compensate for any variation in light intensity from the sensor LED, the reflectivity of both the erased drum surface and the pattern on the drum are checked. VSG is detected every time the machine starts copying. During VSG detection, the development sleeve rollers do not rotate and no development bias is applied. VSP is detected after copying is completed if 10 or more copies have been made since VSP was last detected. Since the transfer belt must be released when checking VSP, a VSP check cannot be done during continuous copying. LED ON LED ON VSG VSP 4 V Drum [A] [B] [C] bias 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 29 30 31 VSP Detection VSG Detection VSP Detection 1st Series of Copies (8 copies) 3rd Series of Copies (17 copies) 2nd Series of Copies (5 copies) VSG Detection VSG Detection VSG Detection VSP Detection Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-15

bias is determined during process control data initial setting as follows: Apply charge while grid voltage is –700 V to create the ID sensor pattern. Check the drum potential (VP) of the latent image created by the charge with –700 V grid. Adjust the ID sensor bias (VIDB) so that it satisfies the following formula. VIDB = VP – (–300) (V) = VP + 300 (V) Change the bias to the calculated VIDB and detect VSP. VSG detected during VSG adjustment sequence in the process control data initial setting and VSP are used to determine VREF data at process control data initial setting. VIDB is not changed until the next process control data initial setting is done. After the series of copies is completed in the case that 10 or more copies have been made, VREF is updated by referring to the previous VREF (VREF’), VSG, VSP and the current TD sensor output (VTD). Since this VREF data updating is under fuzzy control, the relationship among VREF, VREF’, VSG, VSP and VTD cannot be expressed by a simple algebraic formula. VREF is updated not only at the above case. But also during developer initial setting and during process control data initial setting. 4.0 V VSP VP VIDB = VP +300 (V) z ID Sensor Output x Potential Sensor Detection y ID Sensor Bias Level VP –300 x y z –700 V PROCESS CONTROL 23 April 1993 2-16

a. ID sensor (VSG,VSP) abnormal Whenever VSG falls under 2.5 V or VSP rises over 2.5 V, the CPU fixes the VREF data and toner concentration is controlled only by using TD sensor output. VSG and VSP are still detected as usual during abnormal conditions and if output returns to normal levels (VSG ≥ 2.5 V, VSP ≤ 2.5 V), the CPU returns the toner concentration control to normal mode. b. TD sensor (VTD) abnormal Whenever VTD rises over 4.0 V or VTD falls under 0.5 V, the CPU shifts the toner supply to the fixed supply mode. In this condition, the CPU never stops the toner supply. The fixed toner supply amount can be changed in four steps (4%, 7%, 11%, 14%) by using SP mode. The default fixed toner supply amount is 4%. VTD is still detected as usual during the abnormal condition and if its output returns to a normal level, the CPU returns the toner concentration control to normal mode. c. Drum Potential Sensor abnormal Whenever V100 rises over 1.6 V or V100 falls under 0.1 V or whenever V800 rises over 5.0 V or V800 falls under 2.7 V, the CPU also shifts the toner supply to the fixed supply mode, as for a TD sensor (VTD) abnormal condition. Related SC codes. (See troubleshooting section of details.): Code Condition 351 Abnormal VSG Detection (VSG > 4.2 V) 352 Incomplete TD Sensor Initial Setting 353 Abnormal VSP Detection (VSP > 2.5 V) 354 Abnormal VSG Detection (VSG ≤ 2.5 V) 355 Abnormal VTD Detection (VTD > 4 V) 356 Abnormal VTD Detection (VTD < 0.5 V) 357 Abnormal VSP/VSG Detection (VSP/VSG ≥ 0.25 V) 358 Abnormal VSP/VSG Detection (VSP/VSG < 0.25 V) 361 Incomplete Drum Potential Sensor Calibration Detailed Descriptions 23 April 1993 PROCESS CONTROL 2-17

2.1 OVERVIEW The drum unit consists of the components as shown in the above illustration. An organic photoconductor drum (diameter: 100 mm) is used for this model. 3 7. 8 6 4 5 12 9 2 14 1 13 15 16 10 11 1. OPC Drum 2. OPC Drum Protective Shutter 3. Erase Lamp 4. Drum Potential Sensor 5. Pre-transfer Lamp 6. Pick-off Pawl 7. Image Density Sensor 8. Drum Thermistor 9. Cleaning Brush 10. Toner Collection Coil 11. Cleaning Blade 12. Ozone Filter 13. Cleaning Filter 14. Charge Power Pack 15. Quenching Lamp 16. Main Charge Corona Unit DRUM UNIT 23 April 1993 2-18

An OPC has the characteristics of: 1. Being able to accept a high negative electrical charge in the dark. (The electrical resistance of a photoconductor is high in the absence of light.) 2. Dissipating the electrical charge when exposed to light. (Exposure to light greatly increases the conductivity of a photoconductor.) 3. Dissipating an amount of charge in direct proportion to the intensity of the light. That is, where stronger light is directed to the photoconductor surface, a smaller voltage remains on the OPC. 4. Being less sensitive to changes in temperature (when compared to selenium F type drums). 5. Being less sensitive to changes in rest time (light fatigue). This makes it unnecessary to compensate development bias voltage for variations in rest time. Detailed Descriptions 23 April 1993 DRUM UNIT 2-19

2.3.1 Overview This copier uses a double corona wire scorotron system for drum charge. Two corona wires are required to give sufficient negative charge on the drum surface because of a rather high drum speed (330 mm/sec.). The stainless steel grid plate makes the corona charge uniform and controls the amount of negative charge on the drum surface by applying the negative grid bias voltage. The charge power pack [A] gives a constant corona current to the corona wires (1100 µA) and bias voltage to the grid plate is automatically controlled to maintain proper image density according to the change of the OPC drum potential due to dirty grid plate and charge corona casing. [A] DRUM UNIT 23 April 1993 2-20

The exhaust fan [A] located above the fusing unit provides an air flow to the charge corona unit to prevent uneven built-up of negative ions that can cause an uneven charge of the drum surface as shown. An ozone filter [B] absorbs the ozone (O3) around the drum. The exhaust fan rotates slowly during stand-by and rotates quickly during copying to keep the temperature inside the machine constant. [A] [B] Detailed Descriptions 23 April 1993 DRUM UNIT 2-21

The flow of air 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 located at the front end position (home position). After 5000 or more copies are made and fusing temperature is less than 100°C after the main switch is turned on, the wire cleaner motor turns on to bring the wire cleaner to the rear end 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. There are no home position and return position sensors. The CPU monitors the input voltage (5 V). When the wire cleaner reaches the end, it is stopped and the motor is locked. At this time, input voltage slightly decreases (to about 4 V) and the CPU judges to rotate the motor in reverse. [A] [A] [B] [C] [C] DRUM UNIT 23 April 1993 2-22

3.5 ± 2.5 mm SE: Side erase margin total of both sides 3 mm or less Lo: Original width Lc: Charged width of drum EL: Lead edge erase Es: Side erase The erase lamp unit consists of a line of 123 LEDs extending across the full width of the drum, the width of each being about 2.5 mm. In editing mode, the appropriate LED’s turn on according to the customer’s designation. SE LC LO ES LE EL Detailed Descriptions 23 April 1993 DRUM UNIT 2-23

The entire line of LEDs turns on when the main motor turns on. They stay on until the erase margin slightly overlaps the lead edge of the original image on the drum (lead edge erase margin). It prevents the shadow of the original lead edge from appearing on the copy paper. This lead erase margin is also necessary for the lead edge of the copy paper to separate from the hot roller. The width of the lead edge erase margin can be adjusted by SP mode ( SP Adjustment mode: PAGE 3). When the scanner reaches the return position, the charge corona, the grid bias, and the exposure lamp turn off. However, the charged area on the drum surface is a little longer than the actual original length in order to have the entire latent image of the original. The entire line of LEDs turn on when the trail edge of the latent image has passed under the erase lamp unit. This prevents developing unnecessary parts of the drum surface, reducing toner consumption and drum cleaning load. The LEDs stay on to erase the lead edge of the latent image in the next copy cycle. After the final copy, the erase lamps turn off at the same time as the main motor. 2.4.3 Side Erase Based on the combination of copy paper size and the reproduction ratio data, the LEDs turn on in blocks. This prevents the shadow of the original side edge and unexposed front and rear sides of the drum surface in reduction mode from being developed. This reduces toner consumption and drum cleaning load. In the DJF mode, the horizontal original standard position on the exposure glass is 5 mm away from the rear scale. In the RDH mode, the horizontal center of the original is aligned with the center of the exposure glass. On the other hand, the horizontal original standard position on the exposure glass in the platen cover mode is the rear scale edge. To erase the shadow made by the edge of the rear scale in platen cover mode, one more LED at the front side turns on. This is in addition to the LED’s on in DJF and RDH modes. 1 DRUM UNIT 23 April 1993 2-24

The blade [A] is angled against drum rotation. This 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] is used to support the cleaning blade. The brush collects toner from the drum surface and scraped by the cleaning blade. Toner on the cleaning brush is scraped off by the mylar [C] and falls to the toner collection coil [D]. Toner is transported to the toner collection bottle by the toner collection coil. To remove the accumulated toner at the edge of the cleaning blade, the drum turns in reverse for about 4 mm at the end of every copy job. The accumulated toner is removed by the cleaning brush by this action. [A] [C] [B] [D] 4 mm Detailed Descriptions 23 April 1993 DRUM UNIT 2-25

The drive force from the main motor is transmitted to the cleaning unit drive gear via the timing belt [A] and the cleaning unit coupling [B]. The cleaning unit drive gear [C] then transmits the force to the front side through the cleaning brush [D]. The force at the front side is used for the toner collection coil gear [E]. [A] [B] [C] [D] [E] DRUM UNIT 23 April 1993 2-26

The spring [A] always pushes the cleaning blade against the OPC drum. The cleaning blade pressure can be manually released by pushing up the release lever [B]. To prevent cleaning blade deformation during the transportation, the release lever is locked in the pressure release (upper) position. The pin [C] at the rear end of the cleaning blade holder touches the cam gear [D] which gives a side-to-side movement to the blade. This movement helps to disperse accumulated toner to prevent early blade edge deterioration. [A] [C] [B] [D] Detailed Descriptions 23 April 1993 DRUM UNIT 2-27

Toner collected by the cleaning unit is transported to the toner collection bottle [A] through the toner collection tubes. Three helical coils are used for toner transport. One coil [B] is driven by the main motor via drive belts and the other coil [C] is driven by an independent toner collection drive motor [D]. The actuator disk [E] on the toner collection drive motor monitors the proper rotation of the toner collection coil [C] to prevent the coil from being damaged by toner clogged in the collection tube. The main PCB monitors the sensor output and increases the motor speed if the sensor monitors that the toner collection motor rotates at a speed lower than normal. Also, the CPU will display an SC 342 if no signal changes (ON → OFF) are detected for more than 2.55 seconds while the toner collection motor is turning. When the toner collection bottle [A] become full, the toner pressure in the bottle increases and presses the gear [F] against the toner overflow switch [G]. After the toner overflow switch is activated, the finishing of the copy job, or up to 100 continuous copies, is allowed, then copying is prohibited and the service call "full toner collection bottle" indication is displayed on the LCD. This condition can be cleared by de-actuating the toner overflow switch while de-actuating then actuating the toner collection bottle switch ([C] in next page). [A] [E] [B] [F] [C] [G] [D] DRUM UNIT 23 April 1993 2-28

The pick-off pawls are always in contact with the drum surface with weak spring pressure. They move side to side during the copy cycle. This movement is made via a shaft [A] and an eccentric cam [B]. 2.5.6 Toner Collection Bottle Set Detection The toner collection bottle set switch [C] prohibits machine operation by indicating SC343 while the toner collection bottle is not set. [C] [B] [A] Detailed Descriptions 23 April 1993 DRUM UNIT 2-29

neutralizes any charge remaining on the drum. The quenching lamp consists of a line of 16 LEDs extending across the full width of the drum. Yellow colored LEDs are used for QL to reduce ultra violet light which would cause light fatigue on the OPC drum. [A] DRUM UNIT 23 April 1993 2-30

the OPC drum. This forms a latent electrical image of the original. On this model a halogen lamp (85 V 230 W) is used for the exposure lamp [A]. Lamp surface is frosted to ensure even exposure. Six mirrors are used to make the optics unit smaller and obtain the wide reproduction ratio range (50 ~ 200%). The lens [B] is driven by two stepping motors for (1) vertical direction (parallel to the paper feed direction) and (2) horizontal direction movements. To correct focal length change in reduction and enlargement modes, the third scanner unit [C] (4th and 5th mirrors) position is changed by a stepping motor. The toner shielding filter [D] is green (a green filter partly absorbs red light) to improve red original duplication. The optic anti-condensation heater [E] (located on the optic base plate) turns on while main switch is turned off to prevent the moisture from forming on the optics. [A] [B] [C] [D] [E] Detailed Descriptions 23 April 1993 OPTICS 2-31

speed is 330 mm/sec. during scanning, and 1950 mm/sec. when the scanner goes back. The scanner drive motor drives the first [B] and second scanners [C] using two scanner drive wires via the timing belt [D] and the scanner drive shaft [E]. The second scanner speed is half of the first scanner speed. The scanner drive wire is not directly wound around the pulley on the scanner drive motor. [A] [D] [B] [E] [C] OPTICS 23 April 1993 2-32

The lens vertical drive motor [A] changes the lens vertical position in accordance with the selected reproduction ratio. A stepping motor (approx. 0.095 mm/step) is used to drive the lens through the lens drive belt. The maximum lens vertical shift distance is 290 mm (from the position at 50% to the position at 200%). The lens vertical home position sensor [B] detects the lens vertical position for full size mode. The optic control PCB keeps track of the lens position based on the number of pulses sent to the lens vertical drive motor. [A] [B] (Enlarge → HP) (Reduce → HP) (Enlarge → Enlarge) (Reduce → Reduce) (Enlarge → Reduce) (Reduce → Enlarge) Reduce Enlarge HP (100%) steps 30 30 30 30 Detailed Descriptions 23 April 1993 OPTICS 2-33

The original horizontal position on the exposure glass varies depending on the mode (such as platen, DJF and RDH modes) for easy original handling. However, the center is the standard position for paper feed. Therefore, the lens horizontal position has to be changed according to paper size, reproduction ratio, original feed modes and the edit modes (centering, margin adjust, etc.). A stepping motor (approx. 0.07 mm/step) is used to drive the lens through the lens drive belt. The lens horizontal home position sensor [A] is used to detect the lens horizontal position for A4/LT sideways, in full size and platen mode. The other positions are determined by counting the number of motor drive pulses. Since this model has a horizontal lens drive mechanism, side-to-side registration adjustment for each feed station can be done easily by using SP mode ( SP Adjustment mode: PAGE 4). 1 [A] Enlarge Reduce HP 40 40 40 steps OPTICS 23 April 1993 2-34

3.5.1 For Original Position There are three standard original positions for the platen, DJF and RDH modes. In platen mode, the original is aligned with both the rear [A] and the left [B] original scales (rear left corner [C] is the standard position). In RDH mode, the original position is the center of the left scale [B]. In DJF mode, the original position is 5 mm to front of the platen mode original position to maintain the original transport path (5 mm from the rear scale). The above figure shows the lens horizontal positions for each original mode when identical size paper is used. 3.5.2 For Paper Size To keep high paper feed performance, the center is assigned as the paper feed standard position. Therefore, the lens horizontal position is changed according to the paper size. The figure shows the lens horizontal position for each paper size in full size mode. [A] [B] [C] 2.5 143.5 5 100% Copy Paper Lens Position Horizontal Platen DJF RDH (Center) 100% Copy Paper Original Rear Edge Horizontal Lens Position Detailed Descriptions 23 April 1993 OPTICS 2-35

Original Rear Edge When the reproduction ratio is changed, the vertical position of the lens is changed. At the same time, the total focal length has to be changed to adjust the image focusing. For this focal length change, the horizontal position of the 3rd scanner is also adjusted. The maximum 3rd mirror shift distance is 50 mm (from the position at 100% to the position at 50, 200%). The figure shows the lens horizontal position for 50, 100 and 200%. Original Copy Paper 3rd Scanner Position 100% 100% 50% 50% 200% 200% OPTICS 23 April 1993 2-36

To compensate the focus for reproduction and lens position changes, the 3rd scanner (4th and 5th mirrors) position is changed. A stepping motor [A] (approx. 0.095 mm/step) is used for the 3rd scanner drive. The 3rd scanner home position sensor [B] is used to detect the unit position for full size mode. The optic control PCB keeps track of the unit position based on the number of motor drive pulses. [A] [B] (Reduce/Enlarge → HP) (Reduce/Enlarge → Reduce/Enlarge) (Initialize) (Reduce/Enlarge →Enlarge/Reduce) (Reduce/Enlarge → Reduce/Enlarge) 40 steps 40 steps Detailed Descriptions 23 April 1993 OPTICS 2-37

The optic control board communicates with the main board through a data bus. The optics control board monitors all the sensor signals, encoder output, thermistor output and controls all motors in the optics. At the programmed time, the main CPU sends a scanner start signal to the optics control CPU. The CPU generates a pulse-width modulation (PWM) signal. The PWM signal goes to a driver circuit, which sends drive pulses to the scanner drive motor. An encoder in the scanner drive motor generates pulse signals. A speed/direction control circuit monitors the scanner speed and the direction of the signals, and uses this data to regulate the motor speed. The home position sensor monitors the position of the scanner. When the main switch is turned on, the main CPU confirms the position of the scanner by moving the scanner out of the home position and back again. This data is sent to the optics control CPU. M M M M M E Optics Control Board Main Control Board AC Drive Board Sensors Optic Thermistor Exposure Lamp Encoder Scanner Drive Horizontal Lens Drive Vertical Lens Drive 3rd Scanner Drive Optic Cooling Fan Data Bus Optics Control CPU Main CPU OPTICS 23 April 1993 2-38

In ADS mode the original background density is sensed by the ADS sensor [A] and the main CPU determines an appropriate development bias voltage for the original to prevent dirty backgrounds from appearing on copies. The ADS sensor board is mounted on the rear side of the optics side plate. The sensor board is covered by the sensor housing cover which has a small hole to direct the reflected light from the original to the ADS sensor. The ADS sensor standard voltage is adjusted to 2.7 V when process control data initial setting is performed. The exposure lamp turns on with ID level 4 at the home position and the light reflected by the ADS pattern [B] (white painted) reaches the ADS sensor. The main CPU adjusts the ADS gain data automatically to make the output 2.7 V. This gain data is stored in the RAM board. [A] [B] Detailed Descriptions 23 April 1993 OPTICS 2-39

the ADS sensor output while exposing the ADS pattern at the scanner home position. Then the CPU stores the maximum ADS sensor output as a reference voltage. This means that every ADS check cycle, the first scanning for the original, the ADS reference voltage is renewed by the latest exposure light reflected by the ADS pattern. In the full size mode, the CPU samples the ADS sensor output when the scanner scans the original from 9.7 mm to 18 mm from the left scale edge. The CPU takes the maximum ADS sensor output during the sampling period and compares it with the ADS reference voltage to determine the proper development bias voltage. (See development bias control section for details.) The sampling length of ADS sensor output for the original differs depending on the reproduction ratio because the scanner speed is different. 90 mm 20 mm A B Peak hold [V] ADS Sensor Output ADS Original Voltage A = 9.7 M (mm) M = 1.0 (m = 50 ~ 100) M = m 100 (m = 101 ~ 200) B = 8.25 m x 100 (mm) m: reproduction ratio (50 ~ 200) OPTICS 23 April 1993 2-40

When the image density is set manually, the voltage applied to the exposure lamp changes as shown in the table below. VLAMP: Exposure lamp voltage at ID level 4. This value is determined at process control data initial setting. VBB: Development bias (negative) voltage at ID level 4. This value is determined at process control data initial setting. Lighter Darker VBB VBB –60 VBB –90 VLAMP –5.5 VLAMP –3.5 VLAMP –1.5 VLAMP VLAMP +0.5 VLAMP +3.0 VLAMP +4.5 Dev. Bias Voltage (negative) Exposure Lamp Voltage Manual ID Position 5 3 7 6 4 2 1 Detailed Descriptions 23 April 1993 OPTICS 2-41

The entire exposure lamp surface is frosted to ensure even exposure. To compensate for reduced light at the edge of the lens, a shading plate is placed in front of the lens. The shading plate is fixed to the lens unit. The shading plate compensates the light intensity when the lens horizontal position is shifted ([A] to [C]). Also three shading mylars [D] intercept any diffused reflected light from outside the light path. [D] [D] [D] [A] [B] [C] exposure intensity illumination distribution original [A] [B] [C] Shading plate OPTICS 23 April 1993 2-42

There are three reflective sensors (APS sensors) in the optics cavity for the original size detection. Original width Sensor [A] is used for sensing the original width and Original Length Sensor-1 [B] and Original Length Sensor-2 [C] sense the original length. Inside each APS sensor, there is an LED [D] and three photoelectric devices [E]. The light generated by the LED is broken up in three beams and each beam scans a different point of the exposure glass. If the original or platen 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 platen cover is opened. [E] [D] [A] [C] [B] Detailed Descriptions 23 April 1993 OPTICS 2-43

Length Sensor 2 Width Sensor A4/A3 version LT/DLT version 1 2 3 4 5 6 7 8 9 A3 11 x 7 O O O O O O O O O B4 10 x 14 X O O O O O O O O — 81/2 x 14 X O O – O – O O X F4 8 x 13 X X O O O O O O X A4–L 81/2 x 11 X X X O O O O O X B5–L — X X X O O O O X X A5–L 51/2 x 81/2 X X X O O O X X X B6–L — X X X X O O X X X A6–L — X X X X X O X X X A4–S 11 x 81/2 X X X O O O O O O B5–S — X X X X O O O O O A5–S 81/2 x 51/2 X X X X X O O X X A6–S — X X X X X X X X X NOTE: –L: Lengthwise –S: Sideways Sensors #4 and #6 are not used for LT/DLT version machines. The check is done when the platen position sensor [A] turns on. This is when the platen is positioned about 15 cm above the exposure glass. At this time, only the sensor(s) located underneath the original receive the reflected light and are on. Other sensor(s) are off. Through the on/off data of the nine (seven for LT/DLT version machine) sensors, the main CPU can recognize the original size. In case the copy is made with the platen open, the main CPU decides the original size only through the data when the Print key is pressed. This original size detection method eliminates the necessity for a pre-scan and increases the machine’s productivity. [A] OPTICS 23 April 1993 2-44

system. This system differs from single roller development systems in that (1) it develops the image in a narrower area, (2) it develops the image twice, and (3) the relative speed of each development roller against the drum is reduced. Also, finer toner (Approx. 9 µm) and developer (Approx. 70 µm) are used. Both the DRD system and new supplies improve the image quality, especially of thin horizontal lines, the trailing edges of the half-tone areas, and black cross points. The paddle roller [A] picks up developer in its paddles and transports it to the upper development roller [B]. Internal permanent magnets in the development rollers attract the developer to the development roller sleeve. The upper development roller carries the developer past the doctor blade [C]. The doctor blade trims the developer to the desired thickness and creates backspill to the cross mixing mechanism. The development rollers continues to turn, carrying the developer to the OPC drum [D]. When the developer brush contacts the drum surface, the negatively charged areas of the drum surface attract and hold the positively charged toner. In this way, the latent image is developed. The development roller is given a negative bias to prevent the toner form being attracted to the non-image areas on the drum surface that may have a slight residual negative charge. After turning another 100 degrees, the developer is returned to the paddle roller [A]. [A] [D] [B] [C] Detailed Descriptions 23 April 1993 DEVELOPMENT 2-45

[A] when the development motor [B] (dc servomotor) turns. The gears of the toner hopper are driven by the toner supply roller drive gear [C] when the toner supply clutch [D] activates. The above gears are helical gears. Helical gears are more quiet than normal gears. The teeth of the development drive gear are chamfered so that they smoothly engage with the development roller gear [E] when the unit is installed. [A] [D] [B] [E] [C] DEVELOPMENT 23 April 1993 2-46

developer evenly mixed. It also helps agitate the developer to prevent developer clumps from forming and helps create the triboelectric charge. The developer on the turning development rollers [A] is split into two parts by the doctor blade [B]. The part that stays on the development rollers forms the magnetic brush and develops the latent image on the drum. The part that is trimmed off by the doctor blade goes to the backspill plate [C]. As the developer slides down the backspill plate to the agitator [D], the mixing vanes [E] move it slightly toward the rear of the unit. Part of the developer falls into the auger inlet and is transported to the front of the unit by the auger [F]. The agitator moves the developer slightly to the front as it turns, so the developer stays level in the development unit. [B] [A] [C] [D] [E] [F] [A] [B] [C] [D] [E] [F] Detailed Descriptions 23 April 1993 DEVELOPMENT 2-47

the lower sleeve roller through the receptacle [B] and the lower sleeve roller shaft [C]. Then the bias is applied to the upper sleeve roller through the rear sleeve roller holder made of conductive resin. The development bias prevents toner from being attracted to the background area of the non-image area on the OPC drum where there is residual voltage. Also, the development bias is used to adjust image density according to the conditions the customer selected. [A] [B] [C] DEVELOPMENT 23 April 1993 2-48

The bias output is determined by five factors. The total bias is described as; ADS Mode: VB = VBB + VBU + VBMG + VBA Manual ID Mode: VB = VBB + VBU + VBMG+ VBM VB: Total bias VBB: Base bias VBA: ADS Compensation VBU: User Tool mode ID Selection Compensation VBMG: Magnification Compensation VBM: Manual ID Selection Compensation 1) Base Bias (VBB) As explained in the process control section, the base bias for development is determined by the residual voltage (VR) measured in process control data initial setting. VBB = VR + (–220) 2) ADS Compensation (VBA) According to the original background density, the bias is compensated. The compensation value is determined with the voltage measured by the ADS sensor (ADS sensor output: VADS) as follows: VBA = 234 x (VADS –2.3) NOTE: VBA has a limited range from 0 V to –300 V. [V] VD VL Drum Potential VR Original Density VBB Light Dark 1 2 2.7 VBA (negative) –300 0 1.02 V 1 2 2.3 Dark VADS (V) Light Detailed Descriptions 23 April 1993 DEVELOPMENT 2-49

According to the manual ID selection position, the bias is compensated as follows: VLAMP: Exposure lamp voltage at ID level 4. This value is determined at process control data initial setting. 4) User Tool Mode ID Selection Compensation (VBU) In the User Tool mode, the image density level can be selected from five steps. The VBU is determined by the User Tool ID position setting as follows: Lighter Darker –60 –90 VLAMP –5.5 VLAMP –3.5 VLAMP –1.5 VLAMP → VLAMP+0.5 VLAMP+3.0 VLAMP+4.5 VBM (negative) Exposure Lamp Voltage Manual ID Position 0 5 6 3 4 1 2 7 5 4 3 2 1 VBU (negative) 0 +30 +60 –60 –30 User Tool ID Position Lighter Darker DEVELOPMENT 23 April 1993 2-50

VBMG is determined by the selected reproduction ratio as follows: 4.4.3 Bias Control Out of Copy Cycle To hold the toner on the sleeve rollers while the development sleeve rollers are rotating without image development, a constant –300 V bias is applied. Dev. Bias Voltage (negative) –100 –60 –40 –20 –30 50% 123% 141% 160% 142% 122% 116% 161% 115% 80% 61% 81% 62% Detailed Descriptions 23 April 1993 DEVELOPMENT 2-51

While developing the ID sensor pattern, ID sensor bias is applied. ID sensor bias is determined during process control initial setting as follows: A charge is applied while grid voltage is –700 V to create the ID sensor pattern. The drum potential (VP) of the ID sensor pattern is checked. The ID sensor bias (VIDB) is adjusted so that it satisfies the following formula: VIDB = VP – (–300) = VP + 300 (V) 4.0 V VSG VSP VP VIDB = VP +300 (V) z ID Sensor Output x Potential Sensor Detection y ID Sensor Bias Level VP –300 x y z –700 V DEVELOPMENT 23 April 1993 2-52

When the toner supply clutch [A] turns on, the agitator [B] moves the toner from front to rear and sends the toner to the toner supply roller. The toner supply clutch [A] located inside the development motor [C] applies the rotation from the development motor to the toner supply roller gear [D], which drives the agitator gear [E]. Toner is caught in the grooves on the toner supply roller [F]. Then, as the grooves turn past the opening, the toner falls into the development unit. [A] [D] [C] [E] [F] [F] [B] [B] Detailed Descriptions 23 April 1993 DEVELOPMENT 2-53

The toner end sensor [A] detects if sufficient toner remains in the toner hopper or not. The toner end sensor monitors toner end condition once when the toner supply clutch turns on. When there is little toner inside the toner hopper and toner pressure on the toner end sensor becomes low, the toner end sensor outputs a pulse signal for each (one detection per one copy). The toner near end indication is displayed on the LCD after receiving the pulse signal 150 times (If no pulse signal is output twice continually, the pulse count is canceled). Fifty copies are allowed after entering toner near end condition. After fifty copies are made in toner near end condition, the machine enters the toner end condition and copying is prohibited. When the main switch is turned off and on, or the front door is opened and closed, the machine drives toner supply mechanism and monitors the toner end sensor output. If the toner end sensor does not output the pulse signal twice continually, the toner end condition is canceled. [A] DEVELOPMENT 23 April 1993 2-54

By using an SP mode ( Adjustment mode: PAGE 7), the following 3 kinds of toner supply controls can be selected. • Auto Process Control Mode • Detect Mode • Fixed Mode 1) Auto Process Control Mode Originals have various image proportions and image densities. For the best toner supply control, it is necessary to link the amount of toner supplied on each copy cycle to the amount of toner consumed for each copy. Fuzzy control is used in this model to provide this kind of toner supply control. Fuzzy Control 1 According to data of the ID sensor and TD sensor, the CPU checks the following at every copy cycle: 1. The results of toner supply control (TD sensor output) in the previous copy cycle. 2. How quickly the toner density is changing. Then the CPU decides the most suitable toner supply amount (toner supply clutch on time) for the next copy cycle by using fuzzy logic. 1 Detailed Descriptions 23 April 1993 DEVELOPMENT 2-55

The image on the OPC drum changes due to variations in toner chargeability (influenced by the environment) even if toner concentration is constant. The ID sensor directly checks the image on the OPC drum and shifts the VREF data under fuzzy control to keep the image on the OPC drum constant. NOTE: The toner supply amount is changed at every copy cycle. The target toner density sensor output is updated under the following conditions: 1. During toner density sensor initial setting 2. During process control data initial setting 3. After the copy job is completed in case that 10 or more copies have been made since the last update. (Refer to section 2.1.4 "Image Density Control" for details.) 2) Detect Mode In this mode, only the TD sensor is used to control the toner concentration (VREF data is fixed). The machine performs only fuzzy control 1. In ID sensor abnormal condition or Drum Potential sensor abnormal condition, the machine automatically enter this mode. 3) Fixed Mode In this mode, a fixed amount of toner is supplied every copy cycle as determined (4%, 7%, 11%, 14%) by SP mode ( Adjustment mode: PAGE 7). There is no overtoning detection mechanism. In TD sensor abnormal condition, the machine automatically enters this mode. 1 DEVELOPMENT 23 April 1993 2-56

For easy access, the toner bottle is just inside the front cover. The bottle is positioned horizontally. The bottle drive mechanism transports toner from the bottle to the toner hopper [A]. A worm gear [B] on the bottle drive motor drives this mechanism. The toner bottle has a spiral groove [C] that helps move the toner to the toner hopper. To prevent toner from scattering when the toner bottle is removed from the holder, toner shutter [D] which covers the hole [E] is installed on the toner bottle. When the toner is set on the holder and the lever is lowered, the toner shutter [D] opens to supply toner to the toner hopper. The bottle drive motor turns on 0.7 seconds when the toner end sensor turns on twice continually. [A] [C] [B] [D] [E] Detailed Descriptions 23 April 1993 DEVELOPMENT 2-57

5.1 PRE-TRANSFER LAMP The pre-transfer lamp [A] located in the drum unit is used to prevent incomplete toner transfer. After the latent image is developed but before the image is transferred to the copy paper, the drum surface is illuminated by the pre-transfer lamp. This illumination reduces the negative potential on the drum surface charged by the main charge corona and partially discharged by the exposure. This makes image transfer easier. The pre-transfer lamp is turned on and off by the charge power pack at the same time as when the main motor turns on and off. [A] IMAGE TRANSFER 23 April 1993 2-58

OVERVIEW This model uses a unique transfer belt unit instead of the transfer and separation corona unit. The transfer belt unit consists of the following parts: [A] Transfer belt A belt (length: 321 mm) with high electrical resistance which holds a high negative electrical potential and attracts the toner on the OPC drum onto the paper. Also the electrical potential attracts the paper itself and helps paper separation from the OPC drum. [B] Transfer bias roller Applies transfer voltage to the transfer belt. [C] Transfer belt lift lever (driven by a solenoid) Lifts the transfer belt to contact the transfer belt with the OPC drum. [D] Transfer power pack Generates the constant transfer current. [E] Transfer belt cleaning blade Removes toner attached on the transfer belt to prevent the rear side of the paper from being stained. [F] Discharge plate Helps paper separation from the transfer belt by discharging the remaining negative charge on the transfer belt. [F] [E] [C] [D] [A] [B] Detailed Descriptions 23 April 1993 IMAGE TRANSFER 2-59

MECHANISM The registration rollers [A] starts feeding the paper [B] to the gap between the OPC drum [C] and the transfer belt [D] in proper timing. Immediately when the leading edge of the paper reaches the gap between the transfer belt and the OPC drum, the transfer belt lift lever [E] raises the transfer belt to contact the transfer belt and the OPC drum. The lift lever is driven by a solenoid Then a negative transfer bias –1.5 K ~ –2.0 KV is applied to the transfer bias roller [F] and attracts the positively charged toner [G] on the OPC drum. It also attracts the paper and separates the paper from the OPC drum. [A] [B] [C] [D] [A] [E] [F] [G] –800 V –1.3 K~ –1.8KV –1.5 K ~ 2.0 KV IMAGE TRANSFER 23 April 1993 2-60

completed, the charge on the transfer belt holds the paper to the transfer belt. Before separating the paper from the transfer belt, the transfer belt is discharged by the discharge plate [A]. The transfer power pack [B] inside the transfer belt unit monitors the current fed back from the discharge plate to adjust the transfer current. This way, the current stays constant even if the paper, environmental conditions, and the transfer belt surface resistance are changed. [A] [B] [A] [B] Detailed Descriptions 23 April 1993 IMAGE TRANSFER 2-61

The transfer belt lift solenoid [A] located inside the transfer belt unit turns on to raise the transfer belt to contact the OPC drum at the appropriate timing. The front lever [B] and the rear lever [C] are connected to the solenoid by links [D] and push up the stays [E] when the solenoid turns on. The support spring [F] helps the solenoid to raise the transfer belt. The solenoid turns off after the copy job is finished. The transfer belt must be released from the OPC drum for the following reasons: 1. To prevent the ID sensor pattern on the OPC drum from being rubbed by the transfer belt because the transfer belt is located between the development unit and the ID sensor. 2. To decrease the load to the transfer belt cleaning blade, it is better to keep toner on the non-image area (for example VD, VL, ID sensor pattern developed during process control data initial setting) from being transferred onto the transfer belt. 3. To prevent change of OPC drum characteristics by the influence of additives inside the rubber belt. [B] [A] [F] [E] [E] [D] [C] IMAGE TRANSFER 23 April 1993 2-62

MECHANISM The transfer belt is driven by the main drive motor [A] through belt and gears. Since the transfer belt electrically attracts the paper [B], the transport fan is not required. The charge on the transfer belt is discharged by the discharge plate to reduce paper attraction and paper is separated by the paper stiffness above the transfer belt drive roller [C] where the transfer belt is turning. The tapered parts [D] at both sides of the roller [E] help keep the transfer belt [F] at the center position. [F] [C] [A] [B] [E] [D] [E] [D] [F] Detailed Descriptions 23 April 1993 IMAGE TRANSFER 2-63

Some toner may adhere to transfer belt when paper jams occur, or when the by-pass feed table side fences are set in the wrong position causing the erase lamp to miss some toner. The adhered toner must be removed to prevent the rear side of the copy paper from being stained. The cleaning blade [A] scrapes off any toner remaining on the transfer belt. A counter blade system is used for the transfer belt cleaning. The surface of the transfer belt is coated to make it smooth and so prevent the cleaning blade from being flipped by the transfer belt. The lever [B] on the front end of the cleaning blade releases the cleaning blade when the transfer belt unit is lowered and the lever is pushed by the transfer belt unit support prop. (The transfer belt unit is lowered when the lever [C] is turned anti-clockwise) When the cleaning blade is released, the edge of the cleaning blade rubs the seal so that the seal [D] removes the toner or paper dust on the cleaning blade edge. [D] [A] [B] [C] IMAGE TRANSFER 23 April 1993 2-64

Through idle gears [A], transfer belt drive is transmitted to the toner collection coil [B]. The toner collection coil transports the collected toner to the toner collection bottle. See section 2.2.5 for details. [A] [B] Detailed Descriptions 23 April 1993 IMAGE TRANSFER 2-65

6.1 OVERVIEW This model has three drawer tray paper feed stations. The following table shows the configuration of each feed stations of the A095 and A096 copiers. Feed station A095 copier A096 copier 1st 550 sheets tray 500 + 500 sheets tandem feed tray 2nd 550 sheets universal tray 550 sheets universal tray 3rd 550 sheets tray 1500 sheets built-in LCT Paper can also be fed using the by-pass feed table which has an independent feed mechanism. The by-pass feed table can hold 50 sheets of paper. All feed stations use an FRR feed system. Rotation of the pick-up roller [A] drives the top sheets of paper from each tray to the feed [B] and the separation [C] rollers. The feed and separation rollers then take over paper drive. If more than one sheet is fed by the pick-up roller, the separation rollers rotates in the opposite direction and prevents all but the top sheet from passing through to the registration rollers. [A] [A] [B] [B] [C] PAPER FEED 23 April 1993 2-66

This copier uses an FRR paper feed system using three rollers. 6.2.1 Pick-up Roller The pick-up roller [A] is not in contact with the paper stack before it starts feeding paper. Shortly after the Start key is pressed, the pick-up roller drops down and feeds the top sheet between the feed [B] and the separation rollers [C]. At almost the same time that the paper’s leading edge arrives at the feed roller, the pick-up roller lifts off the paper stack so that it does not interfere with the operation of the feed and separation rollers. The feed and separation rollers then take over the paper feed process. 6.2.2 Feed and Separation Rollers There is a one-way bearing inside the feed roller so it can turn only in one direction. The separation roller is driven in the opposite direction to the feed roller. The separation roller, however, is driven through a slip clutch (torque limiter clutch) which allows it to turn in either direction depending on the friction between the rollers. The separation roller solenoid keeps the separation roller in contact with the feed roller. [B] [A] [C] Detailed Descriptions 23 April 1993 PAPER FEED 2-67

forces acting on it. The slip clutch applies a constant clockwise force (F1). When there is a single sheet of paper being driven between the rollers, the force of friction between the feed roller [B] and the paper (F2) is greater than F1. So, the separation roller turns counterclockwise. If two or more sheets are fed between the rollers, the forward force on the second sheet (F3), becomes less than F1 because the friction between the two sheets is small. So, the separation roller starts turning clockwise and drives the second sheet back to the tray. [B] [A] [B] [A] F2 F2 F1 F1 F2 F3 F3 F1 F1 PAPER FEED 23 April 1993 2-68

The slip clutch [A] consists of the input hub [B] and the output hub [C] which is the case of the clutch as well. The magnetic ring [D] and the steel spacers [E] are fitted onto the input hub. The ferrite ring [F] is fitted into the output hub. Ferrite powder [G] packed between the magnetic ring and the ferrite ring [F] generates a constant torque due to magnetic force. The input hub and the output hub slip when the rotational force exceeds the constant torque. This type of slip clutch does not require lubrication. [E] [C] [G] [F] [B] [D] [A] Detailed Descriptions 23 April 1993 PAPER FEED 2-69

The rotation of the paper feed motor [A] is transmitted to the gear [B] via the timing belt [C], and then transmitted to the separation roller via the feed clutch gear [D], gear [E], gear [F] and gear [G]. If the paper feed station is not selected, the separation roller solenoid [H] de-activates and the separation roller [I] rotates freely in the reverse direction of paper feeding. Gear [B] also transmits the drive to the vertical transport roller [J] via gear [D], idle gear [K] and gear [L]. [A] [B] [C] [K] [L] [J] [D] [D] [F] [G] [H] [B] [E] [I] PAPER FEED 23 April 1993 2-70

clutch [A], separation roller solenoid [B], and the pick-up solenoid [C] turn on at once. When the feed clutch [A] activates to rotate the feed roller [D], the feed roller and the pick-up roller [E] turn together because they are linked by the idle gear [F]. When the separation roller solenoid [B] turns on, the separation roller [G] contacts the feed roller [D] then rotates together with the feed roller in spite of the separation roller’s drive in the opposite direction due to the torque limiter function in the separation roller [G]. When the pick-up solenoid [C] activates, the pick-up roller [E] lowers to make contact with the top sheet of the paper stack and send it to the feed and separation rollers. When the paper feed sensor [H] detects the leading edge of the paper [I], the pick-up solenoid de-energizes to lift the pick-up roller and the paper feed clutch de-energizes at a certain time to wait until it is ready to feed to the registration roller. [A] [E] [B] [F] [D] [G] [I] [H] [C] Detailed Descriptions 23 April 1993 PAPER FEED 2-71

In this model, the separation roller [A] is normally away from the feed roller [B]. When the paper feed station is selected, the separation roller solenoid [C] contacts the separation roller to the feed roller as explained in the previous two pages. This contact/release mechanism has the following three advantages: 1. When the paper feed motor turns on, all separation rollers in each feed stations rotate. If the separation roller is away from the feed roller, it reduces the mechanical load to the paper feed motor and drive mechanism, and also reduces wear of the rubber surface of the separation roller due to the friction between the separation roller and the feed roller. 2. After paper feeding is completed, paper sometimes remains in the gap between the feed roller and the separation roller. If the feed tray is drawn out in this condition, it is possible for the remaining paper to be torn. When the separation roller is away from the feed roller, remaining paper is released from the gap between the feed and the separation rollers. 3. When paper misfeeds occur around this area, the customer can easily pull out the jammed paper between the feed and the separation rollers because the separation roller is away from the feed roller. [C] [A] [B] PAPER FEED 23 April 1993 2-72

When the paper feed clutch [A] activates and the feed roller drive shaft [B] rotates, the lever [C] rotates together with the shaft. However, the lever is immediately stopped by the stopper [D]. After all paper is fed and the paper feed clutch turns off, the paper feed motor still rotates to turn the separation roller [E] in the reverse direction. The separation roller, still contacting the feed roller, turns the feed roller in the reverse direction until the lever hits the rubber cushion [F]. By this feed roller reverse mechanism, the paper remaining in the gap between the feed and the separation rollers returns 3mm to the paper feed tray. After that, the separation roller solenoid turns off to move the separation roller away from the feed roller. This releases the leading edge of the paper and drops the paper to the paper feed tray. This prevents remaining paper from being torn when the feed tray is drawn out. [A] [D] [B] [E] [C] [F] [C] 3 mm [C] Detailed Descriptions 23 April 1993 PAPER FEED 2-73

In this model, paper corner holders [A] are not used to facilitate paper loading. Instead of the corner holders, both paper press arms [B] press down both paper side edges, especially in the case of paper with a face curl. This helps to keep paper from being guided by the tray side fences to prevent paper skew or jam. [A] [B] [B] PAPER FEED 23 April 1993 2-74

When the tray is set in the machine, the machine detects this condition by using several detection methods as shown in the table: Feed station A095 copier A096 copier 1st Tray set switch Tray set signal through the connector 2nd Paper size switch Paper size switch 3rd Tray set switch LCT set signal through the connector When the machine detects that the paper tray is set in the machine, the lift motor [A] rotates and the coupling gear [B] on the tray lift motor engages the pin [C] of the lift arm shaft [D], then turns the tray lift arm [E] to lift the tray bottom plate [F]. [A] [D] [B] [E] [C] [F] Detailed Descriptions 23 April 1993 PAPER FEED 2-75