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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 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. Always replace the ozone filters with the specified ones at the specified intervals. 3. 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 RAM board on the system control board has a lithium battery which can explode if replaced incorrectly. Replace the battery only with an identical one. The manufacturer recommends replacing the entire RAM board. Do not recharge or burn this battery. Used batteries must be handled in accordance with local regulations.
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 FOR LASER UNIT
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:
!
DANGER
INVISIBLE LASER RADIATION WHEN OPEN. AVOID DIRECT EXPOSURE TO BEAM.
>PS<
>P S<
!
DANGER
INVISIBLE LASER RADIATION WHEN DISCONNECT OPTICAL FIBER CABLE. AVOID DIRECT EXPOSURE TO BEAM.
>PS<
SECTION 1 OVERALL MACHINE INFORMATION
1 August 1996
SPECIFICATIONS
1. SPECIFICATIONS
Configuration: Copy Process: Originals: Original Size: Copy Paper Size: Desktop Dry electrostatic transfer system Sheet/Book Maximum A3/11" x 17" Maximum A3/11" x 17" Minimum A5/81/2" x 51/2" sideways (Paper tray) A6/51/2" x 81/2" lengthwise (By-pass) Paper tray: 60 ~ 90 g/m2, 16 ~ 24 lb By-pass: 60 ~ 157 g/m2, 16 ~ 42 lb 5 Enlargement and 7 Reduction
A4/A3 Version 400% 200% 141% 122% 115% 100% 93% 87% 82% 71% 65% 50% 25% LT/DLT Version 400% 200% 155% 129% 121% 100% 93% 85% 77% 74% 65% 50% 25%
Copy Paper Weight:
Reproduction Ratios:
Enlargement
Full size
Reduction
Zoom: Power Source:
25% to 400% in 1% steps 120V/60 Hz: More than 12 A (for North America) 220V ~ 240V/50 Hz: More than 7 A (for Europe) 220V ~ 240V/60 Hz: More than 7 A (for Asia)
1-1
SPECIFICATIONS
1 August 1996
Power Consumption:
Mainframe Only 120V 220V ~ 240V Less than 1.1 kW Less than 850 W Approx. 470 W Approx. 500 W Approx. 1.0 kW Approx. 750 W Approx. 130 W Approx. 130 W Approx. 2.0 W Approx. 2.2 W Full System 120V 220V ~ 240V Less than 1.2 kW Less than 1 kW Approx. 500 W Approx. 530 W Approx. 1.0 kW Approx. 750 W Approx. 140 W Approx. 140 W Approx. 2.2 W Approx. 2.4 W
Maximum Copying Warm-up Stand-by Auto Shut Off
NOTE: Full System: Mainframe + ADF + Paper Tray Unit + Duplex Tray + 1-bin Sorter Noise Emission:
Mainframe Only 1. Sound Power Level Copying 61.5 dB(A) Stand-by 30.0 dB(A) 2. Sound Pressure Level at the Operator Position Copying 47.5 dB(A) Stand-by 17.5 dB(A) Full System 64.5 dB(A) 30.0 dB(A) 52.0 dB(A) 17.5 dB(A)
NOTE: The above measurements were made in accordance with ISO 7779. Full System: Mainframe + ADF + Paper Tray Unit + Duplex Tray + 1-bin Sorter Dimensions (W x D x H): 550 x 580 x 652 mm (21.7" x 22.9" x 25.7") Measurement Conditions 1) With by-pass feed table closed 2) Without the optional paper tray unit 3) Without the ADF Less than 57 kg (126 lb)
Weight:
Copying Speed in Multicopy mode (copies/minute):
A4 sideways/ 11" x 81/2" 15 20 A3/11" x 17" 9 11 B4/81/2" x 14" 10 12
No optional memory With 4MB or 8MB optional memory
Warm-up Time
Less than 30 seconds (20°C, 68°F): 115V machine Less then 35 seconds (20°C, 68°F): 230V machine
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1 August 1996
SPECIFICATIONS
First Copy Time:
Less than 9.8 s (from 1st paper tray to face down copy tray) Less than 8.8 s (from 1st paper tray to face up copy tray) Ten-key pad, 1 to 99 (count up or count down) 7 steps 60 s is the standard setting; it can be changed with a UP mode. 15 min. is the standard setting; it can be changed with a UP mode. Paper Tray: 250 sheets Optional Paper Tray Unit: 500 sheets x 2 Bypass: 100 sheets (A4, B5, A5, B6, 8.5 x 11", 5.5 x 8.5") 10 sheets (A3, B4, 11 x 17", 8 x 13") 1 sheet (non-standard sizes) Cartridge exchange (216 g/cartridge) 8 k copies (A4 sideways, 6% full black, 1 to 1 copying, ADS mode)
· · · · · · · ·
Copy Number Input: Manual Image Density: Automatic Reset: Auto Shut Off Copy Paper Capacity:
Toner Replenishment: Toner Yield: Optional Equipment:
Platen cover Auto document feeder Paper tray unit with two paper trays 1-bin sorter Duplex unit Key counter Tray heater Optical anti-condensation heater
Copy Tray Capacity Memory Capacity:
Multi duplex copy Sort, Rotate Sort
Face down mode: 500 sheets Face up mode: 100 sheets
Standard (4 MB) X O X X 35 15 Optional 4 MB O O O O 99 45 Optional 8 MB O O O O 99 75
Number of pages
A4, LT B4, LG A3, DLT A4 6% ITU-T#4
X: Not AvailableO: Available
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MACHINE CONFIGURATION
1 August 1996
2. MACHINE CONFIGURATION
A D
B E C
F
A193V501.wmf
Version Copier
Fax
Item Copier ADF (Option) Paper Tray Unit (Option) Duplex Unit (Option) 1-bin Sorter (Option) Platen Cover (Option) Memory 4MB (Option) Memory 8MB (Option) Fax Controller (Option)
Telephone (Option) ISDN (Option) HDD (Option) Memory Card (Option) Function Card (Option) Page Memory (Option) Printer Controller (Option) PS Option (Option) HDD (Option)
Printer
Machine Code A193 A628 G697 G694 A629 A645 A642-01 A642-02 A639-01 (115V), -02(230V), -03(France), -04 (TWN) H160 A644-01(115V), -02(230V) A641 H130-54 H130-52 A640 A643-00 (115V), -01(230V) A643-02 A643-03
No. E D F C B
A
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1 August 1996
PAPER PATH
3. PAPER PATH
Optional 1-bin Sorter Face Down Tray
Face Up Tray
Optional Duplex Tray Paper Tray
Optional Paper Tray Unit
A193V005.wmf
1-5
MECHANICAL COMPONENT LAYOUT
1 August 1996
4. MECHANICAL COMPONENT LAYOUT
5 6
2 35 1
3
4
7
8
9
10
11
12
34 33 32 31 30 29
13
14 15 16 17
18 28 19
20 27 26
A193V502.wmf
25
24
23
22
21
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1 August 1996
MECHANICAL COMPONENT LAYOUT
1. 2nd Mirror 2. 1st Mirror 3. DF Exposure Glass 4. Xenon Lamp 5. Exposure Glass 6. Original Width Sensors 7. 1st Mirror 8. Barrel Toroidal Lens (BTL) 9. Original Length Sensors 10. Lens 11. SBU Board 12. Scanner Motor 13. F-theta Mirror 14. 2nd Mirror (Laser Unit) 15. PCU 16. Toner Bottle 17. By-pass Feed Roller 18. By-pass Table 19. Relay Rollers 20. Paper Feed Rollers 21. Bottom Plate
22. Transfer Roller 23. Separation Brush 24. Transport Vacuum Fan 25. Pressure Roller 26. Hot Roller 27. Fusing Exit Roller 28. Left Vertical Door/Face Up Tray 29. Junction Gate 30. Hot Roller Strippers 31. Left Vertical Roller 32. Lower Exit Sensor 33. Polygonal Mirror Motor 34. 3rd Mirror 35. Face Down Tray
1-7
ELECTRICAL COMPONENT DESCRIPTIONS
1 August 1996
5. ELECTRICAL COMPONENT DESCRIPTIONS
Refer to the electrical component layout and the point-to-point diagram on the waterproof paper in the pocket for the locations of these components.
Index Description No. Printed Circuit Boards High Voltage Supply PCB1 54 Board Symbol PCB2 PCB3 PCB4 PCB5 PCB6 PCB7 PCB8 PCB9 Motors M1 M2 M3 M4 M5 M6 Sensors S1 S2 S3 S4 50 58 61 62 51 55 52 53 Lamp Stabilizer PSU LD Unit Operation Panel SBU IOCSS BICU MSU Note Supplies high voltage to the drum charge roller, development roller, transfer roller, and discharge brush. Provides dc power for the exposure lamp. Provides dc power to the system and ac power to the fusing lamp. Controls the laser diode. Controls the touch panel display and LED matrix, and monitors the key matrix. Contains the CCD, and outputs a video signal to the BICU board. Controls the mechanical parts of the printer. Controls all copier functions both directly or through other control boards. Compressed the image data, stores the data, and applies the image editing.
45 36 47 49 37 35
Main Scanner Drive Transport Vacuum Fan Polygonal Mirror Toner Supply Exhaust Fan
Drives the main body components. Drives the 1st and 2nd scanners (dc stepper motor). Aids paper transportation from the transfer roller to the fusing unit. Turns the polygonal mirror. Rotates the toner bottle to supply toner to the toner supply unit. Removes heat from around the fusing unit.
33 31 28 27
Upper Exit Lower Exit Left Vertical Door Left Door Relay
S5 S6 S7
17 10 29 PCU Fusing Exit
Detects misfeeds. Detects misfeeds. Cuts the +5 and +24 Vdc power lines. Detects whether the left door is open or closed. Detects the leading edge of paper from the paper tray and duplex unit to determine the stop timing of the paper feed clutch and duplex feed motor. Also detects misfeeds. Detects when a new PCU is installed. Detects misfeeds.
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1 August 1996
ELECTRICAL COMPONENT DESCRIPTIONS
Symbol S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 Switches SW1 SW2 SW3 SW4 SW5 SW6
Index No. 9 14 15 16 12 11 59 4 5 6 3 1 23
Description Charge Roller H.P Upper Tray Paper End Lower Tray Paper End By-pass Feed Paper End Registration
Note Informs the CPU when the drum charge roller is at home position. Informs the CPU when the upper paper tray runs out of paper. Informs the CPU when the lower paper tray runs out of paper. Informs the CPU when there is no paper in the by-pass tray. Detects the leading edge of the copy paper to determine the stop timing of the paper feed clutch, and detects misfeeds. Detects the width of the paper in the by-pass feed table. Monitors the humidity around the PCU. Detects the width of the original. This is one of the APS (Auto Paper Select) sensors. Detects the length of the original. This is one of the APS (Auto Paper Select) sensors. Detects the length of the original. This is one of the APS (Auto Paper Select) sensors. Informs the CPU whether the platen cover is up or down (related to APS/ARE functions). ARE: Auto Reduce and Enlarge Informs the CPU when the 1st and 2nd scanners are at the home position. Detects the amount of toner inside the development unit.
By-pass Feed Paper Width Humidity Original Width Original Length-1 Original Length-2 Platen Cover
Scanner H.P. Toner Density (TD)
21 32 13 20 19 26
AC Main Right Vertical Guide Upper Paper Size Lower Paper Size Front Door Safety
Supplies power to the copier. Supplies power to operate the machine. Cuts the +5 and +24 Vdc power lines. Determines what size of paper is in the upper paper tray. Determines what size of paper is in the lower paper tray. Cuts the +5VLD and +24V dc power lines and detects whether the front cover is open or not.
Magnetic Clutches MC1 MC2 MC3 MC4 MC5 46 42 43 40 41 Charge Roller Contact Controls the touch and release movement of the drum charge roller. Upper Relay Drives the upper relay rollers. Lower Relay Drives the lower relay rollers. By-pass Feed Starts paper feed from the by-pass feed table. Upper Paper Feed Starts paper feed from the upper paper tray.
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ELECTRICAL COMPONENT DESCRIPTIONS
1 August 1996
Symbol MC6 MC7 MC8 Solenoids SOL1 Lamps L1 L2 L3 Heaters
Index Description No. 44 Lower Paper Feed 39 Registration Development 38
Note Starts paper feed from the lower paper tray. Drives the registration rollers. Drives the development roller.
48
Junction Gate
Moves the junction gate to direct copies to the face up or face down copy tray.
60 2 8
Quenching Scanner Fusing
Neutralizes any charge remaining on the drum surface after cleaning. Applies light to the original for exposure. Provides heat to the hot roller.
Tray (option) H1 H2 Thermistors TH1 TH2 Thermofuses TF1 Counters CO1 CO2 Others LSD1 NF CB 30 56 57 Laser Synchronization Detector Noise Filter (230V machine only) Circuit Breaker (230V machine only) 25 --Total Key (option) 7 Fusing 24 22 Charge Roller Fusing 18 34 Anti-condensation (option)
Turns on when the main switch is off to keep paper in the paper tray dry. Tray heaters are also available for the optional paper feed unit. Turns on when the main switch is off to prevent moisture from accumulating.
Monitors the temperature of the drum charge roller. Monitors the temperature of the hot roller.
Provides back-up overheat protection in the fusing unit.
Keeps track of the total number of copies made. Used for control of authorized use. The copier will not operate until it is installed.
Detects the laser beam at the start of the main scan. Removes electrical noise from the AC input line. Guards against voltage surges in the AC input line.
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1 August 1996
DRIVE LAYOUT
6. DRIVE LAYOUT
1 2 3
10
9 8 7
4
A193V503.wmf
6
5
1. Scanner Drive Motor 2. Development Clutch 3. Charge Roller Contact 4. Main Motor 5. Registration Clutch
6. Lower Paper Feed Clutch 7. Lower Relay Clutch 8. Upper Relay Clutch 9. Upper Paper Feed Clutch 10. By-pass Feed Clutch
1-11
COPY PROCESS
1 August 1996
7. COPY PROCESS
7.1 OVERVIEW
1
A193V505.wmf
Pow er Pack
-90 V
-1750 V 8 2 3 -140 V -900 V 7 -600 V 4
6
5 +15 µA +2 kV
Pow er Pack
A193V506.wmf
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1 August 1996
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 memory. 2. DRUM CHARGE In the dark, the charge roller gives a negative charge to the organic photo-conductive (OPC) drum. The charge remains on the surface of the drum because the OPC layer has a high electrical resistance in the dark. 3. LASER EXPOSURE The processed data scanned from the original is retrieved from the memory and transferred to the drum by a laser beam, which forms an electrical 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 BICU board. 4. 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. 5. IMAGE TRANSFER Paper is fed to the area between the drum surface and the transfer roller at the proper time for aligning the copy paper and the developed image on the drum surface. Then, the transfer roller applies a high positive charge to the reverse side of paper. This positive charge produces an electrical force which pulls the toner particles from the drum surface on to the paper. At the same time, the paper is electrically attracted to the transfer roller. 6. PAPER SEPARATION Paper separates from the drum as a result of the electrical attraction between the paper and the transfer roller. The discharge brush helps separate the paper from the drum. 7. CLEANING The cleaning blade removes any toner remaining on the drum surface after the image is transferred to the paper. 8. QUENCHING The light from the quenching lamp electrically neutralizes the charge on the drum surface.
1-13
BOARD STRUCTURE
1 August 1996
8. BOARD STRUCTURE
8.1 OVERVIEW
Scanner Motor
Flat Cable
SBU
Scanner Sensors Harness
LD Unit
DF Motor
IOCSS
DF Sensors, Solenoids Laser Printer Sensors, Solenoids, Motors, Clutches
BICU
Harness
Polygon Mirror Motor
Laser Synchronization Signal = Optical Cable
High Voltage Supply
MSU
Additional Memory
Peripheral Sensors, Motors, Solenoids, Clutches Operation Panel Harness
Flat Cable Fax Controller Mother Board
Printer Controller Standard Option
A193V504.wmf
1-14
1 August 1996
BOARD STRUCTURE
8.2 DESCRIPTION
1. BICU (Base Engine and Image Control Unit) This is the main board. It controls the following functions: · Engine sequence · Scanner, laser printer engine · Timing control for peripherals · Image processing, video control · Operation control · Corresponding application boards · Machine control, system control 2. IOCSS (I/O and Customer Support System Unit) The IOCSS board handles the following functions: · Drive control for the sensors, motors, solenoids of the printer and scanner · PWM control for the high voltage control board · Serial interfaces with peripherals · Circuit for fusing control 3. SBU (Sensor Board Unit) The SBU deals with the analog signals from the CCD and converts them into digital signals. 4. MSU (Memory Super-charger Unit) The MSU stores and compresses the image data. It also does image editing on the data if requested by the user. An extra 4 MB or 8 MB of memory can be added (see below). 5. Additional Memory (Option) This is an additional image memory board for the MSU. 6. LD Unit This is the laser diode drive circuit board. 7. Mother Board This is the printer control board as well as the BICU interface board. It receives the signals from the printer control board and sends signals to the printer control board.
1-15
SECTION 2 DETAILED SECTION DESCRIPTIONS
1 August 1996
SCANNING
1. SCANNING
1.1 OVERVIEW
[E] [A]
A193D001.wmf
[G]
[F]
[D]
[C]
[B]
The original is illuminated by the exposure lamp (a xenon lamp in this model) [A]. The image is reflected onto a CCD (charge coupled device) [B] via the 1st, 2nd, 3rd mirrors, and lens [C]. The 1st scanner [D] consists of the exposure lamp, a reflector [E], and the 1st mirror [F]. The exposure lamp is energized by a dc supply to avoid uneven light intensity as the 1st scanner moves in the sub scan direction. The entire exposure lamp surface is frosted to ensure even exposure in the main scan direction. The light reflected by the reflector is of almost equal intensity, to reduce shadows on pasted originals. An optics anti-condensation heater [G] is available as an option. It can be installed on the left side of the inner cover. It turns on whenever the power cord is plugged in.
2-1
SCANNING
1 August 1996
1.2
SCANNER DRIVE
[B]
[H] [G] [A] [E]
[D] [G] [E]
A193D546.wmf
[F]
[C]
A stepper motor is used to drive the scanner. The 1st and 2nd scanners [A,B] are driven by this scanner drive motor [C] through the timing belt [D], scanner drive pulley [E], scanner drive shaft [F], and two scanner wires [G]. Book mode The scanner drive board controls and operates the scanner drive motor. In full size mode, the 1st scanner speed is 90 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 (M: 0.25 to 4.00). The returning speed is always the same, whether in full size or magnification mode. The image length change in the sub scan direction is done by changing the scanner drive motor speed, and in the main scan direction it is done by image processing on the BICU board. Magnification in the sub-scan direction can be adjusted by changing the scanner drive motor speed using SP4-101. Magnification in the main scan direction can be adjusted using SP4-008. ADF mode The scanners are always kept at their home position (the scanner H.P sensor [H] detects the 1st scanner) to scan the original. The ADF motor feeds the original through the ADF. In reduction/enlargement mode, the image length change in the sub-scan direction is done by changing the ADF motor speed. Magnification in the main scan direction is done in the BICU board, like for book mode. Magnification in the sub-scan direction can be adjusted by changing the ADF motor speed using SP6-007. In the main scan direction, it can be adjusted with SP4-008, like for book mode.
2-2
1 August 1996
SCANNING
1.3
ORIGINAL SIZE DETECTION IN PLATEN MODE
[B]
[C]
A193D526.wmf
[A]
A193D003.wmf
In the optics cavity for original size detection, there are four reflective sensors in the 115V machines, and six reflective sensors in the 230V machines. The Original Width Sensors [A] detect the original width, and the Original Length Sensors [B] detect the original length. These are the APS (Auto Paper Select) sensors. Each APS sensor is a reflective photosensor. While the main switch is on, these sensors are active and the original size data is always sent to the CPU. However, the CPU checks the data only when the platen cover is opened. The original size data is taken by the main CPU when the platen cover sensor [C] is activated. 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 switch on. The other sensor(s) are off. The main CPU can recognize the original size from the on/off signals from the APS sensors. If the copy is made with the platen fully open, the main CPU decides the original size from the sensor outputs when the Start key is pressed.
2-3
SCANNING
1 August 1996
Original Size A4/A3 version A3 B4 F4 A4L B5L A4S B5S LT/DLT version 11" x 17" 10" x 14" 81/2" x 14" (8" x 13") 81/2" x 11" -- 11" x 81/2" -- L1 O O O O O X X
Length Sensors L2 O O O O X X X L3 O O O X X X X L4 O O X X X X X
Width Sensors S1 O O X X X O O S2 O X X X X O X
O: ON X: OFF NOTE: The length sensors L3 and L4 are used only for 230V machines.
For other combinations, "CANNOT DETECT ORIG. SIZE" will be indicated on the operation panel display. 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's productivity. However, if the by-pass feeder is used, note that the machine assumes that the copy paper is lengthwise. For example, if A4 sideways paper is placed on the by-pass tray, the machine assumes it is A3 paper and scans the full A3 area, disregarding the original size sensors. This can cause excess toner to be transferred to the transfer roller, so users should be instructed to always set the paper lengthwise on the by-pass tray. This problem occurs for the first page only. The registration sensor detects the length of the first page, and will assume that the following sheets of copy paper are the same length. Original size detection using the ADF is described in the manual for the ADF.
2-4
1 August 1996
IMAGE PROCESSING
2. IMAGE PROCESSING
2.1 OVERVIEW
CCD
SBU
Fax Controller Drum LD Driver LD Controller (GAVD) FCI TX IPU MSU Printer Controller
LDDR
BICU
RX
Fax Controller
A193D501.wmf
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 BICU (Base-engine and Image Control Unit) board. The BICU board can be divided into three image processing blocks; the IPU (Image Processing Unit), FCI (Fine Character Image), and LD controller (GAVD) · IPU: Auto shading, filtering, magnification, correction, and gradation processing · FCI: Smoothing (binary picture processing mode only) · LD controller: LD print timing control and laser power PWM control Finally, the BICU board sends the video data to the LD drive board at the correct time.
2-5
IMAGE PROCESSING
1 August 1996
2.2
SBU (SENSOR BOARD UNIT)
Amp.
SBU
Z/C Z/C
A/D
BICU
ODD CCD EVEN
IPU
AGC Reference Controller
Vin
ref
Analog Processing IC
Z/C: Zero Clamp AGC: Automatic Gain Control Circuit
A193D502.wmf
The CCD converts the light reflected from the original into an analog signal. The CCD line has 5,000 pixels and the resolution is 400 dpi (15.7 lines/mm). The CCD has two output lines, for odd and even pixels, to the analog processing IC. The analog processing IC performs the following operations on the signals from the CCD: 1) Z/C (Zero Clamp): Adjusts the black level reference for even pixels to match the odd pixels. 2) Signal Composition: Analog signals for odd and even pixels from the CCD are merged by a switching device. 3) Signal Amplification The analog signal is amplified by operational amplifiers in the AGC circuit. The maximum gains of the operational amplifiers are controlled by the CPU on the BICU board. After the above processing, the analog signals are converted to 8-bit signals by the A/D converter. This will give a value for each pixel on a scale of 256 grades. Then, the digitized image data goes to the BICU board.
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1 August 1996
IMAGE PROCESSING
2.3
AUTO IMAGE DENSITY (ADS)
[A]
Sub scan direction
A193D004.wmf
This mode prevents the background of an original from appearing on copies. The copier scans the auto image density detection area [A] as shown in the diagram. This corresponds to a few mm at one end of the main scan line. As the scanner scans down the page, the IPU on the BICU detects the peak white level for each scan line. The IPU determines the reference value for the A/D conversion for a particular scan line using the peak white level for that scan line. Then, the IPU sends the reference value data to the reference 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.
2-7
IMAGE PROCESSING
1 August 1996
2.4
IPU (IMAGE PROCESSING UNIT)
2.4.1 Overview
BICU
SBU + IPU MSU
Tx
Fax controller
CPU BUS CPU
+
+ LD Unit
GAVD
FCI 1 bit Data + 8 bit Data
Printer controller
Rx Fax Controller
A193D527.wmf
The image data from the SBU goes to the IPU (Image Processing Unit) IC on the BICU board, which carries out the following processes on the image data: 1. Auto shading 2. Filtering (MTF and smoothing) 3. Magnification 4. correction 5. Grayscale processing 6. Binary picture processing 7. Error diffusion 8. Dithering 9. Video path control 10. Test pattern generation The image data then goes to either the LD controller (GAVD) or the FCI depending on the selected copy modes.
+
2-8
+
1 August 1996
IMAGE PROCESSING
2.4.2 Image Processing Path
SBU
Text mode Text/Photo mode
ADS and Auto Shading Photo mode Smoothing Main Scan Magnification/ Reduction
IPU
MTF Correction
Correction (Scanner)
Grayscale Processing Dithering Line Width Correction Error Diffusion Binary Picture Processing
Fax Controller
Image Compression/ Decompression, Image Rotation/Adjust Image
MSU
Printer Controller
Video Path Controller
Edge Smoothing Line Width Correction Laser Diode Power Modulation Correction (Printer)
FCI
BICU
LDDR
A193D506.wmf
2-9
IMAGE PROCESSING
1 August 1996
2.4.3 Auto Shading
A193D517.wmf
As with the previous digital copiers, there are two auto shading methods. One is black level correction and the other is white level correction. Auto shading corrects errors in the signal level for each pixel. 1) Black Level Correction The CPU reads the black dummy data from one end of the CCD signal (64 pixels at the end are blacked off) and takes the average of the black dummy data. Then, the CPU deletes the black level value from each image pixel. 2) White Level Correction Before scanning the original, the machine reads a reference waveform from the white plate. The average of the white video level for each pixel is stored as the white shading data in the FIFO memory in the IPU chip. The video signal information for each pixel obtained during image scanning is corrected by the IPU chip. In book mode, auto shading is done at the beginning of each scan. In ADF mode, auto shading is done at a specific time interval. This interval can be set with SP4-913 (the default setting is 30 seconds). The machine waits until the end of the page before doing the auto shading.
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1 August 1996
IMAGE PROCESSING
2.4.4 Filtering and Main Scan Magnification/Reduction 1. Overview After auto shading, the image data is processed by both filtering and main scan magnification. However, to reduce the occurrence of moire in the image, the processing order is different depending on the reproduction ratio, as follows. 1) Reduction and Full size Main Scan Reduction Filtering 2) Enlargement Filtering Main Scan Magnification 2. Filtering There are two software filters for enhancing the desired image qualities of the selected original mode: the MTF filter and the smoothing filter. The MTF filter emphasizes sharpness and is used in Text and Text/Photo modes. The smoothing filter is used in Photo mode. The relationships between the coefficient of the filter and the filter strengths are as follows. Note that these relationships are for copier mode only. Fax mode has its own unique table. (Refer to the fax section.) The filter strengths for each mode can be adjusted with SP4-407. NOTE: Never select "1." Abnormal images may result.
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IMAGE PROCESSING
1 August 1996
3. Main Scan Magnification/Reduction Reduction and enlargement in the sub scan direction are done by changing the scanner speed. However, reduction and enlargement in the main scan direction are handled by the IPU chip. The processing for main scan magnification/reduction is the same as in the previous digital machines.
[A]
A193D504.wmf
When making a copy using the ADF, the magnification circuit creates a mirror image. This is because the scanning starting position in the main scan direction is at the other end of the scan line in ADF mode (as compared with platen mode). In platen mode, the original is placed face down on the exposure glass, and the corner at [A] is at the start of the main scan. The scanner moves down the page. In ADF mode, the ADF feeds the leading edge of the original to the DF exposure glass, and the opposite top corner of the original is at the main scan start position. To create the mirror image, the CPU stores the main scan line data in the LIFO (Last In First Out) memory of the magnification block, from the last pixel. When loading the main scan line data from the LIFO memory, the CPU loads the first pixel of the main scan line.
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1 August 1996
IMAGE PROCESSING
2.4.5 Gamma () 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 data for the scanner gamma correction is fixed and stored in the memory. The printer gamma correction can be adjusted with SP 2-916. 2.4.6 Gradation Processing These are four types of gradation processing: · Grayscale processing: This has 64 output levels for each pixel, and is used only in one-to-one copy mode. · Binary picture processing: This has only two output levels (black and white), and is used in memory copying (e.g., multiple copy, rotate sort, and editing image) and facsimile transmission. · Error diffusion: In Text/Photo mode, this is used with either grayscale processing or binary processing. · Dithering: In Photo mode, this is used with either grayscale processing or binary processing. These four processes are used as follows. 1) Grayscale processing mode Text mode: Grayscale processing Text/Photo mode: Grayscale processing + error diffusion Photo mode: Grayscale processing + dithering 2) Binary picture processing mode Text mode: Binary picture processing Text/Photo mode: Binary picture processing + error diffusion Photo mode: Binary picture processing + dithering Copying using the memory (e.g., multiple copying) and fax mode always use binary picture processing. (Users requiring grayscale mode output for multiple copies will have to take a succession of one-to-one copies.) For one-to-one copying, the processing mode used depends on the setting of SP 4-403. The factory setting is for grayscale processing.
2-13
IMAGE PROCESSING
1 August 1996
1. Grayscale Processing As stated on the previous page, this process generates up to 64 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 (LDDR), and will be explained in the Laser Exposure section. Briefly, the width of the laser pulse for a pixel depends on the output level (from 0 to 63) required for the pixel. For each pixel, the location of the active (laser on) part of the pixel can be either at the left side of the pixel, at the center, or at the right side (see fig 2). The machine determines which method to use depending on the settings of SP 2-903. There are different settings for pixels at the left edge, at the right edge, and in the middle of a series of black/grey pixels across the main scan, and for single black pixels with white pixels at the left and right. The edges of characters and lines become clearer with this processing.
Fig. 1
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Fig. 2
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2. Binary Picture Processing Each video signal level is converted from 8-bit to 1-bit (black and white image data) in accordance with a threshold value. The threshold value can be adjusted with SP 4-418. The printout density of the black pixel depends on the pixel type (left, center, or right of a series, or isolated, in the same way as for grayscale processing). These values can be adjusted with SP2-904.
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1 August 1996
IMAGE PROCESSING
3. Error Diffusion This is used only in Text/Photo mode. The error diffusion process 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 compared with a error diffusion matrix. Separate error diffusion matrixes are used for copy mode and fax mode. 1) Grayscale processing mode The output image signal level has 9 levels (from white to black). There is only one matrix available. 2) Binary picture processing mode The output image signal level has just 2 levels (white and black). The threshold level can be changed with SP4-418-2. 4. Dithering This is only used in Photo mode. Each pixel is compared with a pixel in a dither matrix. Several matrixes are available, to increase or decrease the detail on the copy. 1) Grayscale processing mode The matrix type can be selected with SP4-421-1 and with UP mode. 2) Binary picture processing The matrix type can be selected with SP4-421-2 and with UP mode. 2.4.7 Line Width Correction This function is effective only in Letter mode. Usually, lines will bulge in the main scan direction as a result of the negative/positive development system that is used in this model. So, pixels on edges between black and white areas are compared with adjacent pixels, and if the pixel is on a line, the line thickness will be reduced. The line width correction in grayscale processing mode is done in the IPU, and in binary processing mode, it is done in the FCI chip.
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IMAGE PROCESSING
1 August 1996
2.5
MSU (MEMORY SUPER-CHARGER UNIT)
IPU Memory Controller CPU BUS
DRAM
BICU
MSU
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The MSU consists of the memory controller and the DRAM. The functions of each device are as follows. Memory Controller: Compressing the 1-bit image data Image rotation Image data transfer to the DRAM Stores the compressed data (2 MB) Working area (2 MB)
DRAM (standard 4MB):
The data which was treated with binary picture processing goes to the MSU. The data is first compressed using the MMR process and the compressed data is stored in the DRAM. When printing, the data from the DRAM goes back to the memory controller, where the data is decompressed and image editing is done (e.g., image rotation, repeat image, combine image). The memory capacity changes when optional memory is installed on the MSU board. The copier functions for each memory combination are as follows.
Standard (4 MB) X O X X 35 15 Optional 4 MB O O O O 99 45 Optional 8 MB O O O O 99 75
Multi duplex copy Sort, Rotate Sort
Number of pages
A4, LT B4, LG A3, DLT A4 6% ITU-T#4 (12% black)
X: Not Available
O: Available
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1 August 1996
IMAGE PROCESSING
2.6
FCI (FINE CHARACTER AND IMAGE)
The FCI performs image smoothing and line width correction. These functions only affect binary picture processed images in Letter mode. The fax board and the printer controller each have independent smoothing circuits.
A193D511.wmf
Usually, binary picture processing generates jagged edges on characters as shown in the above left illustration. The FCI reduces jagged edges of characters using the image smoothing process. Whether or not the object pixel undergoes smoothing depends on the surrounding image data. The smoothing process for the object pixel is done by changing the laser pulse positioning and the laser power. FCI smoothing can be switched on or off with SP 2-902.
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LASER EXPOSURE
1 August 1996
3. LASER EXPOSURE
3.1 OVERVIEW
This machine uses a laser diode to produce electrostatic images on an OPC drum. The laser diode unit converts image data from the BICU board into laser pulses, and the optical components direct these pulses to the drum. To produce a high quality copy image, these are 64 gradations for the laser pulses, controlled through power modulation and pulse width modulation. 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 the beam is 0.6 mW on the drum surface at a wavelength of 780 nm. There are four polygon motor speeds:
Resolution (dpi) 400 dpi 600 dpi 391.16 dpi 406.4 dpi Modes Copy, Fax, and Printer Printer Fax (Image rotation) Fax (mm printing) Motor Speed (rpm) Data Frequency (MHz) 14173.23 9.276 21259.84 20.872 13860.00 9.216 14400.00 9.216
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LASER EXPOSURE
3.2
OPTICAL PATH
[B] [E] [F] [D] [G] [H] [C] [E] [D]
[A]
[B] [G]
[H]
[F]
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The output path from the laser diode to the drum is shown above. The LD unit [A] outputs the laser beam to the polygon mirror [B] through the cylindrical lens [C]. Each surface of the polygon mirror reflects a full main scan line. The laser beam goes to the F-theta mirror [D], 1st mirror [E], and BTL [F]. The 2nd mirror [G] reflects the laser beam to the drum through the toner shield glass. The laser synchronizing detector [H] determines the main scan starting position.
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LASER EXPOSURE
1 August 1996
3.3
GRADATION CONTROL (LASER POWER MODULATION)
PM (8 levels) Data: 0 7 5 3 1 0 PWM 0 (8 levels) 1 dot
Data: 3
Data: 7
Data: 11
Data: 15
Data: 34
Data: 63
7
1
1
2
2
5
7
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Black
White 63
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To make the latent image, the laser beam illuminates the image area of the drum surface. The longer the laser is on and the stronger its intensity is, the darker the developed pixel becomes. Modulating (changing) the width of the pulse makes the on time of the laser longer or shorter (PWM). There are eight pulse width levels in this model. While the laser is on to make one dot, the intensity of the laser is controlled by power modulation (PM). The laser's intensity is controlled by the amount of current sent to the laser diode. Modulating the power makes the laser brighter or dimmer. There 8 power levels, or laser intensity levels. The power is modulated only on the final part of the laser pulse (example: see data 11 in the diagram). The machine uses the 8 pulse width levels and 8 power levels to create the 64 possible grayscale values for each pixel.
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1 August 1996
LASER EXPOSURE
3.4
AUTO POWER CONTROL (APC)
LD5V
LD Drive Board
LD IC 1 IC 3 IC 2
DATA DATA LVL2 LD1 PD
LDOFF LVL1 ERR LEVEL
LDERR LDOFF
A193D521.wmf
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, the output light intensity is monitored through a photodiode (PD) enclosed in the laser diode. The photodiode passes an electrical current that is proportional to the light intensity. The output is not affected by temperature, so it faithfully reflects the changes in the LD output, without adding anything itself. Just after the machine is turned on, IC2 on the laser drive board excites the laser diode at full power and the output of the photodiode is stored as a reference in IC2. IC2 monitors the current passing through the photodiode (PD). Then it increases or decreases the current to the laser diode as necessary, comparing it with the reference level (LVL2). Such auto power control is done during printing while the laser diode is active. The laser diode level is adjusted on the production line. Do not touch the variable resistors on the LD unit in the field.
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LASER EXPOSURE
1 August 1996
3.5
LD SAFETY SWITCHES
A193D008.wmf
To ensure that the laser beam does not inadvertently expose the drum during servicing, there are two safety switches located at the front cover. These two switches are installed in series on the LD5 V line coming from the dc power supply board. When the front cover is opened, the power supply to the laser diode is interrupted.
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1 August 1996
PCU (PHOTOCONDUCTOR UNIT)
4. PCU (PHOTOCONDUCTOR UNIT)
4.1 OVERVIEW
10 9 11 12 1 2 13 3
4 6 5 8 7
A193D010.wmf
The PCU consists of the components shown in the above illustration. An organic photoconduntor (OPC) drum (diameter: 30 mm) is used in this machine. 1. OPC Drum 2. Doctor Blade 3. Developer Cartridge 4. TD Sensor 5. Mixing Auger 1 6. Mixing Auger 2 7. Development Roller The output of the humidity sensor is used for toner density control processing. 8. Toner Collection Coil 9. Cleaning Blade 10. Charge Roller Thermistor 11. Charge Roller 12. Charge Roller Cleaning Pad 13. Humidity Sensor
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PCU (PHOTOCONDUCTOR UNIT)
1 August 1996
4.2
DRIVE MECHANISM
[D]
[B] [C]
[A]
A193D542.wmf
The drive from the main motor [A] is transmitted to the drum through a series of gears, a timing belt [B], and the drum drive shaft [C]. The main 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 (this prevents banding and jitter from appearing on copies).
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1 August 1996
PCU (PHOTOCONDUCTOR UNIT)
4.3
NEW PCU DETECTION MECHANISM
[A]
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[B]
[B]
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The PCU sensor [A] detects when a new PCU is installed. Each PCU has an actuator. When a new PCU is installed in the machine, the actuator [B] pushes the PCU sensor. The actuator is a sector gear, and this gear engages with the drum gear. When the drum rotates, the actuator is released from the drum gear. The actuator drops away from the PCU sensor and remains in this "down" position for the duration of the PCU's life. The machine recognizes when a new PCU has been installed in the machine because the actuator of the new PCU contacts the PCU sensor. After the front cover is closed, the machine then performs the TD sensor initial setting procedure automatically (for about two minutes). During this time, the drum rotates and the actuator drops away from the sensor.
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PCU (PHOTOCONDUCTOR UNIT)
1 August 1996
4.4
DRUM CHARGE
4.4.1 Overview
[C]
[E]
[D]
[A] [B] [F]
A193Dd543.wmf
This copier uses a drum charge roller system instead of a corona wire scorotron system to charge the drum. For the copy image area or during roller cleaning, the drum charge roller [A] contacts the surface of the drum [B] to give it a negative charge. The drum charge roller system has the following advantages over the corona wire scorotron charge system. · The amount of ozone generated during drum charging is less than about 1/10 of that for a corona wire scorotron system. · The applied voltage is 1/2 ~ 1/3 that of a corona wire scorotron system. · The efficiency of drum charge is high. Due to these advantages, no ozone filter is required in this copier. The high voltage supply board [C] gives a negative dc voltage to the drum charge roller through the charge roller terminal [D], rear pressure spring [E], and the rear roller bushing [F]. This gives the drum surface a negative charge of 900 V.
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1 August 1996
PCU (PHOTOCONDUCTOR UNIT)
4.4.2 Charge Roller Contact Mechanism [B] [C] [D] [A] [D] [E]
[E]
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[C]
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To prevent toner from adhering to the drum charge roller and to prevent the drum charge roller from sticking to the drum, the drum charge roller contacts the drum only under the following conditions: · When the image processing area comes under the drum charge roller · During charge roller cleaning This function is performed by the charge roller contact clutch [A] (a one-third turn clutch) charge roller H.P. sensor [B], and cam [C] located at the end of the clutch shaft. When the clutch is driven one third of a complete rotation, the pressure lever [D] riding on the cam presses down the drum charge roller unit [E] to contact the roller with the drum. When the drum charge roller contacts the drum, the drum charge roller is turned by the drum. The following table shows the relationship between the clutch rotation and each processing mode.
Mode Clutch Copying 1/3 turn Cleaning (see next page) 1/3 turn Home Position 1/3 turn
Charge Roller Position
Charge Roller Contact H.P. Sn
OFF
OFF
ON
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PCU (PHOTOCONDUCTOR UNIT)
1 August 1996
4.4.3 Drum Charge Roller Cleaning [B] [A]
[C]
[C]
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A193D015.wmf
If the drum charge roller gets dirty, drum charge efficiency decreases. This affects the copy quality, for example causing vertical black lines. Drum charge roller cleaning is done for 2 seconds after every copy job. After the copy job, the charge roller contact clutch is driven another third of a rotation (see the diagram at the bottom of the previous page). The pressure lever presses down more, so that the cleaning pad [A] contacts the charge roller. After charge roller cleaning, the clutch is driven the final third of the rotation (until the charge roller H.P sensor [B] is activated) to release the charge roller from the drum. The pressure lever moves away from the charge roller unit. Then the charge roller unit is released from the drum by the spring [C].
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PCU (PHOTOCONDUCTOR UNIT)
4.4.4 Temperature Compensation
[A]
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The voltage transferred from roller to drum varies with the temperature around the drum charge roller. The lower the temperature is, the higher the applied voltage required. To compensate for this, the drum charge thermistor [A] detects the temperature around the drum charge roller. Before the copy job starts, the CPU monitors the temperature and instructs the high voltage supply board to correct the charge voltage in accordance with the temperature.
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PCU (PHOTOCONDUCTOR UNIT)
1 August 1996
4.5
DEVELOPMENT
[C] [D] [G] [A]
4.5.1 Overview
[F] [E] [B]
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This copier uses a single roller development system. The developer cartridge [A], which includes the developer, is just above the development unit section of the PCU. At machine installation, the developer falls into the development unit. The mixing augers [B] transport the developer and toner to the development roller [C]. Internal permanent magnets in the development roller attract the developer to the development roller sleeve. The development roller carries the developer past the doctor blade [D]. The doctor blade trims the developer to the desired thickness and creates backspill into the mixing mechanism. The development roller continues to turn, carrying the developer to the drum [E] where the latent image is developed. The toner density sensor [F], located on the side of the development unit, measures the toner concentration in the developer. The humidity sensor [G] measures the humidity level around the drum.
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PCU (PHOTOCONDUCTOR UNIT)
4.5.2 Drive Mechanism [B] [A] [D]
[C]
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When the development clutch [D] turns on, main motor drive is transmitted to the development drive shaft [A] and the development drive gear [B] through a timing belt [C], and a train of gears. The development drive gears (except for the gears in the development unit) are helical gears. These gears are quieter than normal gears. When the PCU is pushed in, the development drive shaft engages the development roller gear.
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PCU (PHOTOCONDUCTOR UNIT)
1 August 1996
4.5.3 Mixing [C] [A]
[B]
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This copier uses 2 mixing augers, [A] and [B], to keep the developer evenly mixed. Mixing auger 1 [A] transports excess developer, scraped off the development roller [C] by the doctor blade, towards the front of the machine. Mixing auger 2 [B] returns the excess developer, along with new toner, to the rear of the mixing assembly. Here the developer is reapplied to the development roller.
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PCU (PHOTOCONDUCTOR UNIT)
4.5.4 Development Bias [A]
[C]
[B]
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This machine uses a negative-positive development system, in which black areas of the latent image are at a low negative charge (about -140 ± 50 V) and white areas are at a high negative charge (about -900 V). To attract negatively charged toner to the black areas of the latent image on the drum, the high voltage supply board [A] applies a bias of -600 volts to the development rollers throughout the image development process. The bias is applied to the development roller shaft [B] through that shaft's gear [C]. The development bias is kept at 0V until the latent image comes to the development roller. This is to prevent toner from transferring to the area of drum near the development roller, which has not yet been charged. The development bias is then increased to -600 V at the same time as the development clutch turns on. The development bias voltage (-600 V) can be adjusted with SP2-201.
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PCU (PHOTOCONDUCTOR UNIT)
1 August 1996
4.5.5 Toner Density Control - Toner Density Control Flow Chart Copy
1
VT detection
2
VTREF determination
VTE determination
3
VT VTREF = VT
Yes VT > VTE No
Has the copy job been finished? No
Yes
4
No VT > 0 Yes
Have 30 copies been made?
Yes
See the Toner End Detection Flow Chart
No
5
Toner supply motor on time calculation
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Each step is explained in more detail on the following pages.
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PCU (PHOTOCONDUCTOR UNIT)
- Toner Density Sensor -
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Developer consists of carrier particles (ferrite) and toner particles (resin and pigment). 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 of the sensor changes accordingly. The output from the sensor (VT) is checked before every copy. The machine tries to keep VT constant by varying the toner supply, as shown in the flow chart on the previous page.
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PCU (PHOTOCONDUCTOR UNIT)
1 August 1996
- Toner Density Sensor Initial Setting The TD sensor initial setting procedure is performed in the factory. During TD initial setting, the machine calibrates the TD sensor control voltage (VCONT) so that the TD sensor output voltage is 2.0 ± 0.1V using new developer with a standard toner concentration (6% by weight, 21.6 g of toner in 360 g of developer). This factory-adjusted value will be used for toner density control processing. - Toner Density Measurement Toner density in the developer is detected once every copy cycle (point "1" on the flow chart). The sensor output voltage (VT) during the detection cycle is compared with the toner supply reference voltage (VTREF). - Toner Supply Reference Voltage (VTREF) Determination The toner reference voltage (VTREF) is the TD sensor initial setting voltage, corrected for humidity as detected by the humidity sensor (point "2" on the flow chart). To change the image density, the humidity correction coefficient for VTREF can be changed using SP 2-911 (there are five settings). The larger the value entered in this SP mode, the lighter the copies will be. - Toner Supply Determination VTREF is the threshold voltage for determining whether or not to supply toner. If VT becomes greater than VTREF (points "3" and "4" on the flow chart), the machine supplies additional toner.
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PCU (PHOTOCONDUCTOR UNIT)
- Toner Supply Motor On Time Calculation The toner motor on time is decided by the following factors (point "5" on the flow chart). · VT (this is VT - VTREF) · Copy volume counter · Paper size
The copy volume counter (CVOL) is determined as follows: 0: 1-9 consecutive copies have been made with VT > 0 1: 10-19 consecutive copies have been made with VT > 0 If VT becomes negative at any time (i.e., there is enough toner), CVOL decreases to 0. The toner motor on times are shown below.
Paper Length < 250 mm 0 < VT <= 0.22, CVOL = 0 0 < VT <= 0.22, CVOL = 1 VT > 0.22, CVOL = 0 or 1 0.5 1.0 1.0 Paper Length 250 - 400 mm 0.7 1.3 1.3 Paper Length > 400 mm 0.9 1.8 1.8
NOTE: The toner supply amount is 0.1 g for 0.5 s 4.5.6 Toner Supply in Abnormal sensor Conditions There are two service codes for a TD sensor error. These SC conditions can be cleared by turning the main switch off and on again. After doing this, the machine automatically performs the TD sensor initial setting. 1. TD sensor error 1 When the TD sensor output voltage (VT) is less than 0.5 V, 20 seconds after the TD sensor initial setting has been performed, SC390 will be generated. 2. TD sensor error 2 When the TD sensor initial setting is finished, if the TD sensor output voltage (VT) exceeds the specified range (2 ± 0.2 V), SC393 is generated.
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4.5.7 Toner Supply - Toner Bottle Replenishment Mechanism [E] [F]
[G] [C] [D]
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[A] [H] [B]
[E]
[F]
[G]
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When a toner bottle is placed on the bottle holder unit [A] and pushed back in completely and the toner bottle holder lever [B] is put back in the original position, the following happens automatically to allow toner to be supplied to the development unit. · The pin [C] on the toner shutter [D] is pulled out (opened) as a result of the shape of the developer cartridge. · The cap [E] remaining on the toner bottle is pulled away and kept by the chuck [F] away from the movement of the roller [G], which rides along the curved rail behind the toner bottle holder lever. The toner end detection system determines when to drive the toner bottle replenishment mechanism (see Toner End Detection). The toner supply mechanism transports toner from the bottle to the development unit. The toner bottle has a spiral groove [H] that helps move toner to the development unit. When the bottle holder unit is pulled out to add new toner, the following happens automatically to prevent toner from scattering. · The chuck releases the toner bottle cap into its proper position. · The toner shutter shuts the opening as a result of pressure from a spring.
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PCU (PHOTOCONDUCTOR UNIT)
- Toner Supply Mechanism [D] [C] [A]
A193D020.wmf
[B]
The toner supply motor [A] drives the toner bottle [B] and the mylar blades [C]. First, the toner falls down into the toner holder. The toner supply mylar blades transfer the toner to the slit [D], then the toner falls down into the development unit through the opening.
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PCU (PHOTOCONDUCTOR UNIT)
1 August 1996
- Toner Near End/End Detection Copy
VT detection
Has the copy job been finished? No
Yes
4
VT > VTE 0.2 No
V TREF determination
Yes VTE determination
VT VTREF = VT
Is this 5 or more times in a row?
Yes
No
1
VT > VTE Yes
No
Is this the 15th time in a row?
Yes No Toner supply motor on time calculation No V T > 0 Yes VT detection
2
Have 30 copies been made? Yes
No No VT > VTE
Toner supply motor on time calculation
Yes
Toner near end
3
No Have 50 copies been made?
Yes Toner End
A193D541.wmf
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PCU (PHOTOCONDUCTOR UNIT)
There is no toner end sensor in this machine. Instead, toner end/near-end is detected using the TD sensor output data. The machine checks for toner near end/end every copy. If toner near-end or toner end is detected during the copy job, it is also checked after finishing the copy job. To detect toner near end, the machine first decides the toner end reference voltage (VTE) based on the TD sensor initial setting and the humudity sensor output. Then, the machine compares VTE with the TD sensor output voltage (VT): this is point 1 on the flow chart. During a copy job: If VT is greater than VTREF (this means the amount of toner in the development unit is low), the machine supplies toner (see Toner Supply). If toner concentration is still low after 30 copies (point 2 on the flow chart), the machine checks for a toner near end condition (if VT is greater than VTE, there is a near end condition). If toner concentration is still low 50 copies after toner near-end was determined (point 3 on the flow chart), the machine detects a toner end condition. After a copy job: When the machine detects that toner concentration is low, after the copy job is finished, the machine decreases VTE by 0.2 V and compares the new VTE with VT ("4" on the flow chart). If the toner concentration is still low, the machine supplies toner. The machine then compares VTE with VT again, and supplies toner again if VT is too low. If the toner concentration is still too low after supplying toner 15 times ("5" on the flow chart), the machine detects a toner near-end condition. If toner concentration is still low 50 copies after toner near-end was determined ("3" on the flow chart), the machine detects a toner end condition. The number of copies between toner near-end and toner end can be changed with SP 2-213. The default is 50.
- Toner End Recovery If the front cover is opened and closed for more 10 seconds while a toner near-end/end condition exists and the toner bottle is replaced, the machine will attempt to recover for 3 minutes using the same procedure as for toner near-end/end detection after a copy job.
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4.6
DRUM CLEANING AND TONER RECYCLING
[A]
4.6.1 Drum Cleaning
[B]
A193d010.wmf
5 mm
A193D529.wmf
The cleaning blade [A] removes any toner remaining on the drum after the image is transferred to the paper. This model uses a counter blade system. The toner remaining on the drum is scraped off by the cleaning blade, and it falls onto the toner collection coil [B]. To remove the toner and other particles that are accumulated at the edge of the cleaning blade, the drum turns in reverse for about 5 mm at the end of every copy job, as shown in the illustration. However, this is not done during transfer roller cleaning.
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PCU (PHOTOCONDUCTOR UNIT)
4.6.2 Toner Recycling [A]
[C]
[B]
A193D016.wmf
Toner which falls onto the toner collection coil [A] is transported to the recycled toner transport belt [B] at the front of the PCU. The recycled toner transport belt carries the toner to mixing auger 2 [C] in the development unit. This toner is mixed with new toner by mixing auger 2 and used again.
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5. PAPER FEED
5.1 OVERVIEW
[E] [D] [A]
[B]
[F]
[G] [C]
A193D022.wmf
There are two paper trays and a by-pass feed table [A]. The first [B] and second [C] paper trays each hold 250 sheets. The by-pass feed table can hold 1, 10, or 100 sheets of paper, depending on the paper size. The semicircular feed rollers [D] drive the top sheet of paper from the tray to the registration rollers [E] through the relay rollers [F]. The tray has two corner separators (see [F] in the diagram in the "Paper Lift Mechanism" section), which allow only one sheet to feed at a time. The corner seperators, along with the tray's springs, also serve to set the height of the paper stack. When the tray is closed after the paper is loaded, the paper size actuator located at the front right of the tray pushes the paper size sensor. This informs the cpu what paper size is loaded in the tray and that the tray is in place. There is a relay sensor [G] located between the relay rollers. This sensor is used for paper jam detection.
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PAPER FEED
5.2 PAPER TRAY
5.2.1 Paper Feed Drive Mechanism
[C]
[A]
[C]
[B]
A193D033.wmf
The main motor [A] drives the pick-up and feed mechanism of both the first and second paper trays. The paper feed clutches [B] transfer drive from this motor to the feed rollers [C]. The paper feed clutch turns on and the feed rollers start rotating to feed the paper. The paper feed clutch stays on for enough time to turn the paper feed rollers only once.
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5.2.2 Paper Lift Mechanism [F]
[D]
[E] [A] [C]
A193D024.wmf
[F]
[E]
[B]
When the paper tray [A] is closed after paper is loaded, the release slider [B], which is mounted on the bottom part of the tray, is pushed by the projection [C] on the main frame and the release slider comes off the bottom plate hook [D]. Once the release slider comes off, the bottom plate is raised by the pressure springs [E] and the top sheet pushes up the corner separators [F]. This keeps the stack of paper at the correct height.
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PAPER FEED
5.2.3 Paper End Detection [B] [D]
[A]
[E] [C]
A193D027.wmf
The paper end feeler [A] is on the same shaft as the paper end actuator [B]. When the paper tray runs out of paper, the paper end feeler drops into the cutout [C] in the tray bottom plate. The paper end actuator activates the paper end sensor [D]. The paper end actuator is in contact with the lever [E]. When the tray is drawn out, the lever turns as shown by the arrow in the figure. Then the lever pushes up the actuator. As a result, the feeler rotates upwards. This mechanism is necessary to prevent the feeler from getting damaged by the paper tray body.
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5.2.4 Side Fence Double Stopper Mechanism
[B] [A]
[B] [A]
A193D026.wmf
There is a side fence stopper mechanism for both the front and rear side fences. If the tray is closed with excessive force after loading paper, paper may come over the rear side fence, because the fence is deformed by the weight of the paper leaning against it. As a result, skewing or paper jams may occur. To prevent this, a side fence stopper mechanism has been added to the rear side fence also. The release levers [A] each have a stopper which contains teeth like those on a gear. The guide rails [B] also have teeth. When the release lever is pushed, the gear teeth release each other and the side fences can be moved.
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PAPER FEED
5.2.5 Paper Size Detection
SW Size A3, F( 81/2"x13" ) A4 Lengthwise A4 Sideways A5 Sideways, 11"x17" B4, 81/2"x14"