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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. 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.
6.The copier is not attached to the table. Pushing the copier too heard may
cause it to drop onto the floor. While moving the copier, push the table.
7. When the main switch is tuned on, the machine will suddenly start turning
to perform the developer initialization. Keep hans away from any
mechanical and electrical components during this period.
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.
CAUTION
2. The RAM board on the main control board has a lithium battery
which can explode if replaced incorrectly. Replace the RAM board
only with an identical one. The manufacturer recommends
replacing the entire RAM board. Do not recharge or burn this
battery. Used RAM board must be handled in accordance with
local regulations.
SAFETY AND ECOLOGICAL NOTES FOR DISPOSAL
1. Do not incinerate the toner cartridge or the used toner. Toner dust may
ignite suddenly when exposed to open flame.
2. Dispose of used toner, developer, and organic photoconductor according
to local regulations. (These are non-toxic supplies.)
3. Dispose of replaced parts in accordance with local regulations.
4. When keeping used RAM boards in order to dispose of them later, do not
put more than 100 RAM boards per sealed box. Storing larger numbers
or not sealing them apart may lead to chemical reactions and heat
build-up.
SECTION 1
OVERALL
MACHINE INFORMATION
25 July 1996 SPECIFICATIONS
1. SPECIFICATIONS
Information
Overall
Configuration: Console
Copy Process: Electrostatic transfer system
Original Feed: Sheet feed
Original Size: Maximum: 914 x 3,600 (36" x 142")mm
Minimum: 182 x 257 (B5), 81/2" x 11" lengthwise
Copy Size: Same as "Original Size"
Copying Speed: 7.5 cpm (A1/D sideways)
First Copy: 18 seconds (A1/D sideways)
Warm-up Time: Within 6 minutes (Room temperature 23oC)
Multi-Copy: 1 to 10
Automatic Reset: 2 minutes after copying is finished (can be set
to 1, 3, 4, or 5 minutes or to no auto reset)
Photoconductor: Organic photoconductor drum
Drum Charge: Single-wire with grid plate (Negative Charge)
Reproduction Ratio: 1 : 1 (±0.5%)
Exposure System: Slit exposure via fiber optic array
Exposure Lamp: Fluorescent lamp (26 W)
Development: Dual-component dry toner system
Toner Replenishment: Cartridge system (750 g toner/cartridge)
Toner Consumption: 1,860 A1 or D copies per cartridge (6% original)
Development Bias: Negative
Toner Density Control: Direct toner density detection by induction
sensor
Image Density Adjustment: Development bias control + exposure control
Auto Image Density Control: Development bias control + exposure control
Paper Separation: Dual wire ac corona and pick-off pawls
Cleaning: Cleaning blade
1-1
SPECIFICATIONS 25 July 1996
Paper Feeding: Manual feed and 2 roll feeds
(3rd roll feeder optional)
Image Fusing: Heat and pressure type, teflon (upper) and
silicone rubber (lower) rollers
Fusing Lamp: Halogen lamp
(115 V: 1,100 W, 230 V: 1,100 W)
Self-diagnostic Codes: 18 codes, displayed in copy counter
Power Source: 115 V/60 Hz....12 A
220 V/50 Hz....7 A
230 V/50Hz.....7 A
240 V/50 Hz....7 A
Power Consumption: Maximum: 1.41 kW
Warm-up: 1.21 kW
Ready: 0.1 to 1.2 kW
Copy cycle: 1.36 kW
Dimensions (W x D x H): 1230 x 690 x 1065 mm
48.4" x 27.2" x 41.9"
Weight: 195 kg, 429 lb
Optional Equipment and Machine Configuration
Configuration
Additional equipment
Main frame Optional equipment
A174 3rd Roll feeder (A613)
copier Side guides (A569)
Other Optional Equipment
· Paper Spool (Spare parts)
· Key Counter Bracket Set (A902-15)
· Key Counter (Procured locally)
· Key Counter Holder (Procured locally)
Specifications are subject to change without notice.
1-2
25 July 1996 PAPER PATH
2. PAPER PATH
Information
Overall
E
D
,
,
A
B
F
C
A174V502.wmf
A: Original Path ,Z [, \, ]: D: Original Path from Rear Feeder
Switching back
E: Upper Copy Exit
B: Paper from the manual feed
F: Lower Copy Exit
C: Paper from the roller feed
1-3
DRUM PROCESSES 25 July 1996
3. DRUM PROCESSES
2
1
8
7
3
4
5 6
A174V503.img
1. Charge
In the dark the charge corona unit applies a negative charge to the drum.
The grid plate ensures the charge is applied uniformly. The charge remains
on the surface of the drum because the photoconductive drum has a high
electrical resistance in the dark.
2. Exposure
High intensity light from a fluorescent lamp is reflected from the moving
original through the fiber optic array. The charge on the drum surface is
dissipated in direct proportion to the intensity of the reflected light, thus
producing an electric latent image on the drum surface.
1-4
25 July 1996 DRUM PROCESSES
3. Development
Information
The magnetic developer brush on the development roller comes in contact
Overall
with the latent image on the drum surface. Toner particles are
electrostatically attracted to the negatively charged latent image areas.
4. Pre-Transfer Lamp
The pre-transfer lamp (PTL) illuminates the drum prior to image transfer. This
reduces the attraction between the toner and the drum, thus making image
transfer easier.
5. Image Transfer
Copy paper is fed to the drum surface, at the exact timing, to align the copy
paper and the developed image on the drum surface. Then a strong negative
charge is applied to the back side of the paper. The negative charge pulls
the toner particles from the drum surface onto the paper.
6. Paper Separation
A strong ac corona discharge is applied to the back side of the copy paper,
reducing the charge on the paper and breaking the electrostatic attraction
between the paper and the drum. Then, the stiffness of the copy paper
causes it to separate from the drum. The pick-off pawls help to separate
paper which has low stiffness.
7. Cleaning
The cleaning blade, which is angled against drum rotation (counter blade
system), removes any toner remaining on the drum surface.
8. Quenching
The light from the quenching lamp electrically neutralizes the surface of the
drum.
1-5
MECHANICAL COMPONENT LAYOUT 25 July 1996
4. MECHANICAL COMPONENT LAYOUT
23 25
21 22 24 1 2
3
20
19
18 4
17
5
16 6
15 7
14 8
13 9
10
11
12
A174V500.wmf
1-6
25 July 1996 MECHANICAL COMPONENT LAYOUT
1. Original Registration Roller 14. Paper Registration Rollers
Information
Overall
2. Original Feed Roller 15. Manual Feed Table
3. Copy Tray 16. Development Unit
4. Exit Rollers 17. Toner Cartridge
5. Fusing Exit Rollers 18. Charge Corona Unit
6. Hot Roller 19. Original Table
7. Pressure Roller 20. Original Exit Rollers
8. Gas Spring 21. Original Repeat Roller
9. OPC Drum 22. Exposure Lamp
10. T/S Corona Unit 23. Fiber Optic Array
11. Paper Spool 24. Platen Roller
12. 3rd Roll Feeder 25. Cleaning Blade
13. Cutter Unit
1-7
DRIVE LAYOUT 25 July 1996
5. DRIVE LAYOUT
12 1
11 2
3
10 4
9
8 7 6 5
A174V501.wmf
1. Original Feed Motor 7. Drum Drive Relay Gear
2. Drum 8. Transport Unit Drive Belt
3. Development Unit 9. Fusing Drive Motor
4. Development Relay Gear 10. Fusing Unit
5. Development Motor 11. Exit Unit Drive Belt
6. Main Motor 12. Original Feed Drive Pulley
1-8
25 July 1996 ELECTRICAL COMPONENT DESCRIPTIONS
6. ELECTRICAL COMPONENT DESCRIPTIONS
Information
Overall
Refer to the electrical component layout on the reverse side of the Point to
Point (Water proof paper) index numbers.
Name Function Index No.
Motor
Main Motor Drives the drum and the registration roller. (dc motor) 20
Development Motor Drives the development unit components. (dc motor) 22
Fusing Drive Motor Drives the fusing unit components. (dc motor) 2
Original Feed Motor Drives original feed rollers. (dc motor) 25
Roll Feed Motor Drives the 1st, 2nd and 3rd roll feed rollers. (dc motor) 52
Cutter Motor Drives the roll cutter. (dc motor) 56
Removes the ozone built up around the drum section
Exhaust Fan Motor 7
to the ozone filter. (dc motor)
Provides suction so paper is held firmly on the
Vacuum Motor 1 19
transport belt.
Provides suction so paper is held firmly on the
Vacuum Motor 2 10
transport belt.
Wire Cleaner Motor Drives the wire cleaner. 24
Magnetic Clutches
Transmits the roll feed motor drive to the 1st roll feed
Roll Feed Clutch 1 55
roller.
Transmits the roll feed motor drive to the 2nd roll feed
Roll Feed Clutch 2 58
roller.
Transmits the roll feed motor drive to the 2nd roll feed
Roll Feed Clutch 3 54
roller.
Transmits the main motor drive to the registration
Registration Clutch 23
roller.
Toner Supply Clutch Turns on to supply toner to the development unit. 21
Solenoids
Pick-off Pawl
Moves the pick-off pawls against the drum. 66
Solenoid
Exit Gate Solenoid Moves the exit gate to change paper path. 12
Original Gate
Moves the original gate to change original path. 1
Solenoid
Switches
Main Switch Supplies power to enable copy operation. 37
Exit Cover Open
Detects whether the exit cover is open or not. 33
Switch
Detects whether the cutter unit is at the left home
Left Cutter Switch 57
position or not.
Detects whether the cutter unit is at the right home
Right Cutter Switch 50
position or not.
3rd Roll Feed Door
Detects whether the 3rd roll feed door is open or not. 53
Open Switch
Upper Unit Safety
Cuts ac power when the upper unit is open. 38
Switch
1-9
ELECTRICAL COMPONENT DESCRIPTIONS 25 July 1996
Name Function Index No.
Exit Cover Safety
Cuts ac power when the exit cover is open. 34
Switch
Anti-humidify
Supplies power to the anti-humidify heater. 49
Heater Switch
Roll Feed Unit
Cuts dc power when the roll feed unit is open. 59
Safety Switch
Anti-humidify
Cuts power to the anti-humidify heater when the roll
Heater Safety 48
feed unit is open.
Switch
Sensors
Upper Unit Open
Detects whether the upper unit is open or not. 45
Sensor
ADS Sensor Senses the background density of the original. 61
Fusing Exit Sensor Detect paper jams after the registration sensor. 8
Roll Lead Edge Detects the leading edge and trailing edge of the
60
Sensor paper fed from the roll feeder.
Roll End sensor 1 Detects the roll end condition of the 1st roll. 42
Roll End sensor 2 Detects the roll end condition of the 2nd roll. 28
Roll End sensor 3 Detects the roll end condition of the 3rd roll. 54
Original Exit Sensor
Detects jams in the original exit section. 14
1
Original Exit Sensor
Detects jams in the original exit section. 3
2
Original Exit Sensor
Detects jams in the original exit section. 18
3
Original Lead Edge Detects the original leading edge to determine the
6
Sensor copy process timing.
Original Switch
Detects original jams in the repeat copy. 4
Back Sensor
Detects when an original is inserted from the front
Original Set Sensor 5
side.
Original Feed Unit
Detects whether the original feed unit is open or not. 47
Open Sensor
Detects the leading edge of the original to
Original
synchronize the original leading edge with the copy 62
Registration Sensor
paper.
Light Sensor Detects the intensity of the exposure lamp output. 27
Rear Original Set Detects when an original is inserted from the rear
9
Sensor side.
Toner Density (TD)
detects the density of toner in the developer. 15
Sensor
Detects when a sheet of paper is set on the by-pass
Paper Set Sensor 16
feed table.
Detects when copy paper arrives at the registration
Registration Sensor 17
roller. Detects paper jams.
Detects whether the used toner bottle is full or not.
Toner Overflow
36
Sensor
1-10
25 July 1996 ELECTRICAL COMPONENT DESCRIPTIONS
Name Function Index No.
Information
Printed Circuit Boards
Overall
Controls all copier functions both directly and through
Main Board 44
other PCBs.
AC Drive Board Provides ac power to the lamps, heaters, and PSU. 39
PSU Converts the ac voltage to dc voltage. 43
Informs the CPU of the selected modes, and displays
Operation Panel 11
the situation on the panel.
Lamps
Provides light to reflect the original' image onto the
Exposure Lamp 26
lamp. (fluorescent lamp)
Fusing Lamp Provides heat to the hot roller. 32
Pre-transfer Lamp Reduces the charge on the drum surface prior to
13
(PTL) image transfer.
Quenching Lamp Neutralizes any charge remaining on the drum
65
(QL) surface after cleaning.
Power Packs
Charge/Bias/Grid Provides high voltage for the charge corona, grid and
40
Power Pack development bias.
Provides high voltage for the transfer corona and
T & S Power Pack 30
separation.
Thermistors
Hot Roller
Monitors the hot roller surface temperature. 29
Thermistor
Pressure Roller
Monitors the pressure roller surface temperature. 33
Thermistor
Heaters
Anti-humidity Heater Removes humidity from the roll paper. 63
Anti-condensation
Prevents moisture from forming inside the copier. 64
Heater
Others
Fusing Thermofuse Protects against fusing overheat. 31
Keeps track of the total length of copies made
Total Counter 46
(Europe) or total number of copies made (U.S.A.).
Noise Filter Filters electrical noise on the ac power input lines. 35
Stabilizes the power supplement to the exposure
FL Regulator 41
lamp.
1-11
SECTION 2
DETAILED SECTION
DESCRIPTIONS
25 July 1996 DRUM
1. DRUM
1.1 DRUM CHARACTERISTICS
The organic photoconductor (OPC) drum has the following characteristics:
· It is able to accept a high negative electrical charge in the dark. (The
Descriptions
electrical resistance of the OPC drum is high in the absence of light.)
Detailed
· The electric charge on the drum surface dissipates when the drum is
exposed to light. (The conductivity of the OPC drum is greatly enhanced by
exposure to light.)
· It dissipates an amount of charge that is in direct proportion to the intensity
of the light. That is, where stronger light is directed to the photoconductor
surface, a smaller voltage remains.
The OPC drum used in this model has high sensitivity, good color
reproduction, and good reproduction of low contrast originals (pencil
originals, etc.)
2-1
DRUM 25 July 1996
1.2 DRUM DRIVE
[E] [F]
[A]
[D]
[C]
[B]
A174D517.wmf
The OPC drum [A] is 80 millimeters in diameter and 970 millimeters long. It
turns constantly when the main motor [B] is on.
When the main motor turns on, the drive is transmitted to the drum in the
following way:
main motor drive gear [C] idle gears [D] drum drive gear [E]
drum flange [F] drum
When the drum knob is tightened, the right flange presses firmly against the
drum so that the drum is held tightly between the flanges. The drum and
flanges turn together when the main motor is on.
2-2
25 July 1996 CHARGE
2. CHARGE
2.1 OVERVIEW
Descriptions
Detailed
[A]
[B]
A174D501.wmf
A174D502.wmf
This model uses a single wire corona unit [A] to charge the OPC (organic
photoconductor) drum [B]. The corona unit generates a corona of negative
ions when a high negative voltage is applied to it by the charge/grid power
pack.
To make the negative corona uniform, a grid consisting of 8 wires is installed
on the charge corona unit between the corona wire and the drum. This grid
drains off any charge in excess of 860 volts, thus preventing fluctuation of
the charge potential.
2-3
CHARGE 25 July 1996
2.2 CHARGE CORONA CIRCUIT
A174D503.wmf
The main board supplies +24 volts (VAA) to the charge/bias/grid power pack
as the power supply source. Approximately 12 seconds after the copy
process starts, the CPU drops CN102-B7 from 5 volts to 0 volts. This
actuates the dc/dc converter within the power pack which applies a high
negative voltage of approximately 5.0 kV to the charge corona wire. The
corona wire then generates a negative corona charge.
The grid limits the maximum corona charge to 860 volts. This ensures that
the charge does not fluctuate and an even charge is applied to the drum
surface.
The copy grid voltage and charge voltage amounts can be adjusted using
SP# 14 and SP#13 respectively.
The grid drive signal applied to CN320-4 is a pulse width modulated signal.
As the width of the pulses applied increases, the strength of the grid charge
also increases. The main board monitors the grid charge at CN102-B4 and
controls the width of the drive pulses based on this feedback.
2-4
25 July 1996 CHARGE
2.3 CHARGE WIRE CLEANING MECHANISM
Descriptions
Detailed
[A]
[B]
A174D501-2.wmf
The wire cleaner pads [A] automatically clean the wires every 297 m (500
copies/A1).
The wire cleaner is driven by a dc motor [B]. Normally the wire cleaner is
located at the front end position (home position). After 297 m (500 copies/A1)
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, 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.
2-5
CHARGE 25 July 1996
2.4 CORONA UNIT VENTILATION
[A]
A174D504.wmf
If ozone produced by the corona charge stays in the charge corona area, it
may cause uneven corona charging to the drum. To prevent this, ozone is
vacuumed out through the exhaust fan [A], and changed to oxygen by the
ozone filter before being blown out of the copier.
2-6
25 July 1996 EXPOSURE
3. EXPOSURE
3.1 OVERVIEW
Descriptions
Detailed
[E]
[D]
[B]
[G] [F]
[C]
[A]
A174D505.wmf
Light from the exposure lamp [A] reflects off the original and through the fiber
optics [B] to the OPC drum [C]. During exposure, the original moves across
the exposure glass at the same speed as the drum's peripheral velocity.
The platen roller [D] presses the original [E] flat against the exposure glass
[F] just above the fiber optic array. This ensures that the image is properly
focused. (The original must be within 0.2 mm of the exposure glass surface.)
The exposure lamp is a 125 V, 37 W exposure lamp.
The light sensor [G] monitors the intensity of the exposure lamp output.
2-7
EXPOSURE 25 July 1996
3.2 PAPER AND ORIGINAL FEED
3.2.1 Normal Original Feed
[A] [B]
[D]
[C]
[Q]
[E]
[P]
[O]
[F]
[N]
[J]
[K]
[I] [H]
[L]
[G]
P: Original Exit Sensor
Q: Original Switch Back Sensor
[M] A174D506.wmf
When an original is placed on the original table, it activates the original set
sensor [A]. The main motor and development motor start rotating and the
exposure lamp turns on. 2.5 seconds later, the original feed motor starts
rotating to turning the original feed roller [B] and the original registration roller
[C]. An original feed starts. The 2.5 second delay allows time for the operator
to align the lead edge of the original against the first set of rollers to prevent
skew.
2-8
25 July 1996 EXPOSURE
When the original lead edge sensor [D]detects the leading edge of the
original, the roll feed motor and the roll feed clutch turn on, and paper feed
starts. The original is fed to the original registration sensor [E] and stops at 33
mm [F] ahead of the original registration sensor to wait for the copy paper.
The registration clutch is activated at the appropriate time after paper feed
begins. The copy paper is fed to the registration roller [G] and the registration
clutch turns off when the copy paper reaches 15 mm [H] ahead of the
Descriptions
Detailed
registration sensor [I]. The speed of the roll feed motor is increased from 90
mm/s to 162 mm/s to form a paper buckle [J]. Then, the speed of the roll feed
motor returns to 90 mm/s and the registration clutch turns on again. The
paper feed resumes and the copy paper is transported to the drum [K].
At the appropriate time, the original feed motor rotates again and the original
is delivered to the exposure glass.
To measure the original length for synchro-cutting, the copier CPU counts the
time after the original lead edge sensor [D] detects the leading edge of the
original until the original set sensor [A] detects the trailing edge of the
original. The copy paper length is measured by counting the number of steps
as the roll feed motor (stepper motor) turns. The roll feed motor stops at the
appropriate time and the cutter motor rotates to cut the copy paper.
Repeat copies
When making repeat copies, to increase the CPM, the roll feed motor starts
rotating 0.22 s after the roll lead edge sensor [L] is de-activated and advance
the copy paper 20 mm [M] (140 mm ahead of the paper feed start position).
After the 1st copy job, at the appropriate time after the trailing edge of the
original passes the original registration sensor [E], the original feed motor
rotates reverse 3.6 times as fast as the normal speed. The original is
returned to the position [N] where the leading edge of the original is 8 mm
before the original registration sensor.
When the leading edge of the original passes the original registration sensor,
the original feed motor rotates forwards again and the original is delivered to
the exposure glass and the copy job is repeated at the trigger timing. After
all the repeat copies have been made, the original is fed out.
After original scanning, the original can be stopped and caught by the original
exit rollers [O] or it can be fed out without being caught in the original exit
rollers. This is determined by SP No.24 (Original Hold mode). If the original
hold mode is selected, the original is fed out when the Clear/Stop key is
pressed or the next original is inserted.
2-9
EXPOSURE 25 July 1996
3.2.2 CHANGING MODE TO LONG NARROW ORIGINALS
[A]
A174D535.wmf A174D536.wmf
[B]
[C]
[E]
[Q]
[D]
[O] [P]
[F]
A174D537.wmf
If the original width is less than 515 mm (18'') and it is longer than the
standard paper size (A0/E size), the original may be skewed by the middle
four of the 8 original feed rollers. The copy image may be warped. For such
originals, the "long narrow original" feed mode can be selected. In this mode,
the middle four original feed rollers are released while inserting the original.
When the original feed cover [A] is opened and the green lever at the right [B]
is pulled front, the middle four original feed rollers [C] are released from the
original registration roller [D]. This release condition of the middle four original
feed rollers is detected by the original mode change sensor in the rear feed
table assembly.
When the original cover is closed, "00" is blinking on the copy counter to
distinguish this mode from the normal original feed mode.
In this mode the detection of the original leading edge by the original lead
edge sensor [E] is used as a starting trigger of the main motor, development
motor, and exposure lamp. 3 seconds later, the original registration roller
delivers the original to the exposure glass. To measure the original length for
synchro-cutting, the copier CPU counts the time after the original registration
sensor [F] detects the leading edge of the original until the original lead edge
sensor detects the trailing edge of the original.
The repeat copy function cannot be used in this mode.
2-10
25 July 1996 EXPOSURE
3.3 ROLL FEED
[E] [A] [B]
Descriptions
Detailed
[D]
[F]
[H]
[H]
[H]
[C]
A174D507.wmf
This machine has two standard roll feed units (1st [A] and 2nd [B]), one
manual feed unit, and one optional roll feed unit (3rd [C]). The cutter unit [D]
uses a sliding rotary cutting blade.
When turning on the main switch or when roll paper is replenished, the roll
feed motor rotates and the leading edge of the roll paper is fed until the roll
lead edge sensor [E] is activated. Then, the leading edge of the roll paper is
returned to the paper feed start position (120 mm before the cutter unit) [F].
2-11
EXPOSURE 25 July 1996
3.3.1 Roll End Detection
[A]
A174D508.wmf
The roll paper end sensor [A] is located above each roll. When the roll paper
runs out and the roll paper end sensor detects the black core of the roll, roll
end is indicated on the operation panel. If the paper is not caught by the
pull-out rollers [H] (previous page), paper feed fails. In this case, roll end is
indicated instead of a paper misfeed indication.
3.3.2 Drive Mechanism
[F] [B]
[E] [F]
[H]
[G]
[D]
[C]
[G] A174D509.wmf
[H] [G]
The roll feed roller [B] is driven by the roll feed motor [C] through the chain
[D] and gears [E]. The pull-out roller [F] of each roll feed unit is driven by the
roll feed motor through the chain and each gear [G] and each roll feed clutch
[H].
2-12
25 July 1996 EXPOSURE
3.3.3 Drive Mechanism
[A] [G]
Descriptions
Detailed
[C]
[F]
[B]
[D] [E] A174D510.wmf
The original feed roller [A] is driven through the original feed drive pulley [B]
and belt [C] by the original feed motor [D].
The platen roller [E] is rotated by the original feed motor [D] through the
gears [F] and belt [G].
2-13
EXPOSURE 25 July 1996
3.4 FL REGULATOR CONTROL
[D]
[C]
[A]
A174D511.wmf
The FL regulator [A] receives 24 volts dc at CN401-1 from the main board
[B]. The control signal, which is a pulse width modulated (PWM) signal, is
received at CN401-3. The PWM signal has a period (T) of 1 millisecond and
a duty ratio of 15% to 100%.
The basic light intensity level is determined either by the image density
selected at the operation panel (manual ID control) or by the original's
background level as sensed by the ADS. The CPU uses the light sensor to
monitor the actual light intensity. The light sensor [C] directly detects the
lamp's light output and feeds a light intensity signal back to CN105-B28 of the
main board [D]. This feedback allows the CPU to compensate for variations
in light intensity due to the lamp's age or temperature.
2-14
25 July 1996 EXPOSURE
3.5 MANUAL ID CONTROL VS ADS
Light Sensor Light Sensor
Manual ID Level Manual ID Level
Output [V] Output [V]
1 1.275 14 1.882
2 1.275 15 1.922
3 1.275 16 2.020
Descriptions
4 1.294 17 2.118
Detailed
5 1.294 18 2.216
6 1.314 19 2.314
7 1.333 20 2.412
8 1.373 21 2.529
9 1.412 22 2.627
10 1.510 23 2.725
11 1.627 24 2.824
12 1.745 25 2.922
13 1.843 26 3.118
3.5.1 Manual ID Control
When in manual image density mode, the user can select one of 26 manual
ID levels. For each level, the intensity of the light output by the exposure
lamp (as measured by the light sensor) is fixed. This is shown in the above
table. The development roller bias also varies. (See the section on
development bias.)
2-15
EXPOSURE 25 July 1996
3.5.2 ADS Control
VOD/VSD VS [V] VOD/VSD VS [V]
0~0.45 3.118 0.64~0.65 2.020
0.46~0.47 2.922 0.66~0.67 1.922
0.48~0.49 2.824 0.68~0.69 1.882
0.50~0.51 2.725 0.70~0.71 1.843
0.52~ 0.53 2.627 0.72~0.73 1.745
0.54~0.55 2.529 0.74~0.75 1.627
0.56~0.57 2.412 0.76~0.80 1.510
0.58~0.59 2.314 0.81~0.84 1.412
0.60~0.61 2.216 0.85~0.88 1.373
0.62~0.63 2.118 0.89~ 1.333
VS: Light Sensor Voltage
VOD: Original Density Detecting Voltage
VSD: Standard Pattern (White Plate) Density Detecting Voltage
When automatic image density sensing (ADS) is used, the exposure light
intensity varies depending on the background image density of the original.
The preceding table shows how the exposure light intensity changes
depending on the VOD/VSD ratio.
Use user program mode to select the default ID setting. It can be set to ADS
or Manual ID. The factory setting is ADS.
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25 July 1996 EXPOSURE
3.6 AUTO DENSITY SENSOR (ADS)
Descriptions
Detailed
A174D520.wmf
The ADS measures the reflectivity of the original's background. Based on the
originals background image density, the CPU automatically adjusts the
development bias and exposure light intensity to achieve a good copy image.
The ADS is located at the original registration rollers. It reads the reflectivity
of the white plate by emitting light from ADS (standard white), which is
located above the ADS, prior to the arrival of the original. This standard white
level (VSD) is used for comparison with the background level of the original
(VOD).
The ADS samples a 43.5 mm by 10 mm area near the leading edge of the
original. As shown in the above illustration, sampling starts 15 mm from the
leading edge.
The highest voltage detected by the ADS is held (peak hold) and used for the
exposure voltage adjustment.
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DEVELOPMENT 25 July 1996
4. DEVELOPMENT
4.1 OVERVIEW
[D] [C] [B]
[A]
A174D512.wmf
When the development motor turns on, the paddle roller [A] and development
roller [B] start turning. The paddle roller picks up developer in its paddles and
transports it to the development roller. Internal magnets in the development
roller attract the developer to the development roller sleeve.
The turning sleeve of the development roller then 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 roller continues to turn, carrying the developer to the OPC
drum. 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.
Negative bias is applied to the development roller to prevent toner from being
attracted to non-image areas on the drum that may have residual positive
charge. The bias also controls image density.
After turning about 100 degrees more, the development roller releases the
developer into the developer tank. The developer is agitated by the paddle
roller and the cross-mixing mechanism.
Also, in this machine, rotation of the paddle roller and development roller tend
to cause the air pressure inside the unit to become higher than the air
pressure around the development unit. Therefore, a hole fitted with a filter
has been added to the top of the unit to relieve air pressure and to minimize
toner scattering.
The toner density sensor [D] is mounted on the upper side of the
development unit to detect the density of toner in the developer.
2-18
25 July 1996 DEVELOPMENT
4.2 DRIVE MECHANISM
[D] [C]
Descriptions
Detailed
[B]
[H]
[F]
[I] [G]
A174D513.wmf
[A] [E]
When the development motor [A] is on, the paddle roller [B], development
roller [C], and mixing auger [D] in the development unit are driven through the
development drive belt [E] and gears [F].
The toner agitator shaft [G] is rotated through the gears [H] by the toner
supply clutch [I] engaged in the toner supply condition.
2-19
DEVELOPMENT 25 July 1996
4.3 CROSS-MIXING
[C]
[B]
[F]
[A]
[E]
[D]
"Cross-mixing" keeps the developer's toner and carrier evenly mixed and
evenly distributes the developer within the development unit. Cross-mixing
also agitates the developer to generate the necessary triboelectric charge on
the toner and carrier particles.
The arrows in the above illustration show the developer movement directions
within the machine. The developer that is attracted to the development roller
[A] is split into two parts by the doctor blade [B]. One part (the magnetic
brush) goes on to develop the latent image on the drum. However, the other
part is trimmed off by the doctor blade and directed to the backspill plate [C].
As the developer slides down the backspill plate to the paddle roller [D], part
of the developer falls into the auger inlet [E] and is transported to the left side
of the unit by the mixing auger [F], where it drops onto the paddle roller. The
amount of developer moved to the right by the backspill plate is equal to the
amount moved to the left by the mixing auger.
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25 July 1996 DEVELOPMENT
4.4 TONER DENSITY CONTROL
The toner supply amount ratio is determined by the following conditions.
TS 51 ~ 100 101 ~ 150 151 ~ 200 201 ~ 250
Level 0 ~ 50 sheets
(~ 30 m) sheets sheets sheets sheets 251 sheets ~
(150 m ~)
(30 ~ 60 m) (60 ~ 90 m) (90 ~ 120 m) (120 ~ 150 m)
0 VTS < 4.00 VTS < 3.50 VTS < 3.00 VTS < 2.50 VTS < 2.00 VTS < 1.80
4.00 VTS < 3.50 VTS < 3.00 VTS < 2.50 VTS < 2.00 VTS < 1.80 VTS <
Descriptions
1 4.10 3.80 3.50 3.00 2.40 2.00
Detailed
2 4.10 VTS < 3.80 VTS < 3.50 VTS < 3.00 VTS < 2.40 VTS < 2.00 VTS <
N 4.20 4.10 4.00 3.50 2.80 2.50
3 4.20 VTS < 4.10 VTS < 4.00 VTS < 3.50 VTS < 2.80 VTS < 2.50 VTS <
4.30 4.20 4.20 4.00 3.20 3.00
4 4.30 VTS < 4.20 VTS < 4.20 VTS < 4.00 VTS < 3.20 VTS < 3.00 VTS <
4.40 4.35 4.30 4.25 3.60 3.50
5 4.40 VTS 4.35 VTS 4.30 VTS 4.25 VTS 3.60 VTS 3.50 VTS
0 VTS < 4.25 VTS < 4.00 VTS < 3.50 VTS < 3.00 VTS < 2.50 VTS < 2.00
1 4.25 VTS < 4.00 VTS < 3.50 VTS 3.00 VTS 2.50 VTS 2.00 VTS
4.30 4.10 < 3.80 < 3.50 < 3.00 <2.40
2 4.30 VTS < 4.10 VTS < 3.80 VTS 3.50 VTS 3.00 VTS 2.40 VTS <
L 4.35 4.20 < 4.10 < 4.00 < 3.50 2.80
3 4.35 VTS < 4.20 VTS < 4.10 VTS 4.00 VTS 3.50 VTS 2.80 VTS <
4.40 4.30 < 4.20 < 4.20 < 4.00 3.20
4 4.40 VTS < 4.30 VTS < 4.20 VTS 4.20 VTS 4.00 VTS 3.20 VTS <
4.45 4.40 < 4.35 < 4.30 < 4.25 3.60
5 4.45 VTS 4.40 VTS 4.35 VTS 4.30 VTS 4.25 VTS 3.60 VTS
0 VTS < 4.00 VTS < 3.00 VTS < 2.50 VTS < 2.00 VTS < 1.90 VTS < 1.40
1 4.00 VTS < 3.00 VTS < 2.50 VTS < 2.00 VTS < 1.70 VTS < 1.40 VTS <
4.10 3.50 3.00 2.40 2.00 1.70
2 4.10 VTS < 3.50 VTS < 3.00 VTS < 2.40 VTS < 2.00 VTS < 1.70 VTS <
H 4.20 4.00 3.50 2.80 2.50 2.20
3 4.20 VTS < 4.00 VTS < 3.50 VTS < 2.80 VTS < 2.50 VTS < 2.20 VTS <
4.30 4.20 4.00 3.20 3.00 2.70
4 4.30 VTS < 4.20 VTS < 4.00 VTS < 3.20 VTS < 3.00 VTS < 2.70 VTS <
4.40 4.30 4.25 3.60 3.50 3.20
5 4.40 VTS 4.30 VTS 4.25 VTS 3.60 VTS 3.50 VTS 3.20 VTS
TS Level (Toner Supply Ratio)
0: No supply 1: 7.5% 2: 15% 3: 30% 4: 50% 5: 100%
N, L, H: SP#9 setting
The toner density sensor is used for toner density control. It measures the
ratio of toner to carrier in the developer.
Toner is supplied every 600 mm when the toner density sensor value (VTS)
meets one of the TS level conditions from 1 to 5. The triboelectric charge
generated on the toner and carrier become greater in accordance with the
copy quantity and is stabilized after 250 copies. To compensate the
triboelectric charge characteristic, the value of the toner supply control
changes as shown.
2-21
DEVELOPMENT 25 July 1996
During the initial conditioning, the main motor rotates the development unit to
stabilize the triboelectric charge generated on the toner and carrier and the
toner density sensor is automatically adjusted to 4.0±0.1V using new
developer. The initial conditioning (SP40) must be performed whenever the
developer is replaced.
4.4.1 Toner Near End Condition
When TS level 5 is detected 3 times in a row, the toner near end condition is
detected and the add toner indicator starts flashing. When in the toner near
end condition, 16 more meters (A1/D size: 27 copies) can be copied. Then
the add toner indicator will light and the machine will not operate.
4.4.2 Recovery From Toner End Condition
After replacing the toner cartridge (opening and closing the original feed unit),
the development motor rotates the development unit for 30 seconds. During
this period, toner is supplied at 100% of the supply amount until TS level
reaches 3. Then, copies can be made.
If TS level does not reach less than 3, the CPU stops the machine and
displays the toner end condition. This prevents the operators from resetting
the toner end condition by simply opening and closing original feed unit.
2-22
25 July 1996 DEVELOPMENT
4.4.3 Toner Density Sensor
Descriptions
Detailed
A174D515.img
A174D516.wmf
The toner density sensor circuit controls the amount of toner in the developer
mixture.
The toner density sensor is powered by 12 volts from CN105-B18 of the main
board. (The potential of CN105-B18 is 24 V when the connector is
disconnected.) The sensor's sensitivity is set by the feedback signal applied
from CN105-B16. The input signal from the sensor passes to the main board
at CN105-B17. This is an analog signal.
The active sensor element is a very small transformer with three coils. When
iron ferrite (carrier) is near the sensor element, the inductance of the coils
changes, causing the current through the transformer to change. As the
amount of toner in the developer increases, the effect of the carrier particles
decreases and the voltage applied to CN105-B16 decreases. Conversely,
when the toner concentration drops as toner is used up, the effect of the
carrier on the sensor coils increases and the voltage at CN105-B16 also
increases.
2-23
DEVELOPMENT 25 July 1996
4.5 DEVELOPMENT BIAS
4.5.1 Basic Concept
When the drum is exposed, most of the negative charge is eliminated from
the areas where light strikes the drum. This leaves a negative charge pattern
corresponding to the dark areas of the original. After exposure, however, a
small residual charge of about 100 volts (for white paper) remains in the
exposed areas. This residual charge could attract positively charged toner
from the development roller, resulting in dirty background on the copy.
The development bias prevents this cause dirty background. A negative bias
that is a little larger than the residual charge is applied to the development
roller. This prevents the positively charged toner from being attracted to the
background areas of the latent image.
4.5.2 Manual Image Density Bias
The development bias is applied as shown by the above chart.
In addition to the development bias, the image density is also controlled by
varying the exposure light intensity. (See the exposure section.)
Manual ID Manual ID
Bias (Volts) Bias (Volts)
Level Level
1 60 14 180
2 80 15 180
3 110 16 200
4 120 17 200
5 130 18 200
6 150 19 200
7 180 20 240
8 180 21 240
9 180 22 280
10 180 23 280
11 180 24 280
12 180 25 280
13 180 26 280
2-24
25 July 1996 DEVELOPMENT
4.5.3 Auto Image Density Bias
The ADS can be switched to the "Darker"setting with service program mode
#18 or "Lighter" setting.
In addition to the development bias, the image density is also controlled by
varying the exposure light intensity. (See the exposure section.)
Descriptions
Vod/Vsd Bias [V] Vod/Vsd Bias [V]
Detailed
0~0.45 280 0.64~0.65 200
0.46~0.47 280 0.66~0.67 180
0.48~0.49 280 0.68~0.69 180
0.50~0.51 280 0.70~0.71 180
0.52~ 0.53 280 0.72~0.73 180
0.54~0.55 240 0.74~0.75 180
0.56~0.57 240 0.76~0.80 180
0.58~0.59 200 0.81~0.84 180
0.60~0.61 200 0.85~0.88 180
0.62~0.63 200 0.89~ 180
Vod: Original Density Detecting Voltage
Vsd: Standard Pattern (White Plate) Density Detecting Voltage
4.5.4 Bias Adjustment
Using service program mode #25, the bias level can be increased or
decreased.
2-25
DEVELOPMENT 25 July 1996
4.6 TONER SUPPLY
[C]
A174D519.img
[B]
[A]
[B]
A174D518.wmf
To allow a compact design, the toner supply mechanism is built into the toner
cartridge. An agitator [A] in the toner cartridge turns when the toner supply
clutch is engaged. As the agitator rotates, mylar strips [B] on the ends of the
agitator force toner through small holes (0.5 mm in diameter) in a plastic strip
[C] along one side of the toner cartridge. The toner particles thus ejected
from the cartridge fall into the development unit and are mixed into the
developer. The toner agitator turns at 75 rpm and the toner supply rate is
approximately 22.5 grams per minute.
2-26
25 July 1996 IMAGE TRANSFER AND PAPER SEPARATION
5. IMAGE TRANSFER AND PAPER
SEPARATION
Descriptions
Detailed
[E]
[B] [A] [C] [D]
A174D522.wmf
5.1 PRE-TRANSFER LAMP (PTL)
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 [A]. This
illumination reduces the negative potential on the drum surface. This
prevents toner particles from being re-attracted to the negatively charged
drum during the paper separation process. It also makes image transfer and
paper separation easier.
5.2 IMAGE TRANSFER
The registration rollers [B] feed the copy paper through the transfer entrance
guides to the transfer section. A high negative voltage (about 5.0 kV) is
applied to the transfer corona wire [C], and the corona wire generates
negative ions. These negative ions are applied to the copy paper, and the
negative charge attracts the positively charged toner away from the drum and
onto the paper. In addition, the paper is held against the drum by the positive
counter charge on the drum.
5.3 PAPER SEPARATION
After image transfer, the copy must be separated from the drum. To break
the attraction between the paper and the drum, the separation corona wires
[D] apply an ac corona (5.0 kV) to the reverse side of the paper. The stiffness
and weight of the paper cause it to separate from the drum.
The separation corona has a negative component. This negative component
holds the toner on the paper to prevent it from being reattracted to the drum
during paper separation. The two pick-off pawls [E] ensure that thin paper,
paper with low stiffness, or upward curled paper separates completely from
the drum.
2-27
IMAGE TRANSFER AND PAPER SEPARATION 25 July 1996
5.4 PICK-OFF MECHANISM
[A] [B]
[D]
[C]
A174D521.wmf
The pick-off pawl solenoid [A] is energized afte