Konica 7075 GUIDE MANUAL 7075020e
2
UNIT EXPLANATION
2 UNIT EXPLANATION
EXTERNAL SECTION
[1] Composition
Main switch
Operation panel
Front right door
Right side cover
(upper)
EXTERNAL SECTION
RADF
Left side cover
Left front door
Bypass tray
Tr a y 1
Tr ay 2
Tr a y 3
Right side cover
(middle)
Vertical
Conveyance
door
Cooling
cover
2 UNIT EXPLANATION
Optional cover
Rear cover
Right side cover
(lower)
2 - A - 1
DRIVE SECTION
[1] Composition
DRIVE SECTION
Drum motor (M2)
Main motor (M1)
Developing motor (M3)
Loop roller motor (M6)
Paper feed motor (M4)
[2] Mechanisms
Mechanism
*1 Drum drive
*1 Developing drive
*1 Main drive
*1 Paper feed drive
*1 By-pass/loop drive
*1 Paper exit drive
Driven Parts
Drum, toner guide roller
Developing sleeve
Fixing upper roller
Tray 1/2/3, Vertical conveyance roller
(middle/lower)
By-pass feed roller, loop roller, vertical
conveyance roller (upper)
Paper exit roller
Paper exit motor
(M10)
2 UNIT EXPLANATION
Method
Gear drive (dedicated motor)
Gear drive (dedicated motor)
Gear drive (dedicated motor)
Gear drive (dedicated motor) + Belt
Gear drive (dedicated motor)
Gear drive (dedicated motor)
*1 Independent drive mechanisms
Drive mechanisms are driven by dedicated motors to ensure high-speed operation and to improve serviceability and developing performance.
2 - B - 1
DRIVE SECTION
[3] M1 (Main) Control
MS2 MS1
24VDC
PGND
DCPS2
M1 CONT
M1 EM
2 UNIT EXPLANATION
M1 (main) is controlled by the PRCB (printer control
board) and the motor drive power is supplied from
DCPS2 (DC power supply unit 2).
1. Operation
M1 is a motor driven by 24V DC. It drives fixing
upper and lower rollers, paper conveyance belts,
and thick paper conveyance roller. M1 incorporates a speed controller circuit to send a signal
indicating abnormal rotation to PRCB when the
PLL lock has been released for longer than the
specified period of time.
M1 starts rotating when the START PRINT button is pressed and stops when the last copied
paper has been ejected. During the warm-up
operation, M1 rotates to rotate the fixing rollers.
When either one of the front doors of this machine
opens or closes, MS1 (interlock 1) or MS2
(interlock 2) actuates to stop supplying the DC
power to the motor, causing the M1 to stop.
PRCB
M1
[4] M2 (Drum) Control
MS2 MS1
24VDC
PGND
DCPS2
M2
M2CONT
M2 F/R
SGMD
M2 EN
PRCB
M2 (drum) is controlled by the PRCB (printer control
board) and the motor drive power is supplied from
DCPS2 (DC power supply unit 2).
1. Operation
M2 is a motor driven by 24V DC. It drives a drum,
toner guide brush, toner guide shaft, toner
conveyance screw, and separation claw swing
sections. M2 incorporates a speed sensor (encoder) to send a feedback signal to PRCB. Using
this signal, PRCB detects the rotational speed
and calculates the PWM duty to be given to the
motor, controlling the M2 speed. In addition to
the speed sensor, M2 also has a flywheel mechanism to ensure accurate and steady rotation.
M2 starts rotating when the ST ART PRINT button
is pressed and stops when the last copied paper
has been ejected.
When either one of the front doors of this machine
opens or closes, MS2 (interlock 1) or MS2
(interlock 2) actuates to stop supplying the DC
power to the motor, causing the M2 to stop.
2. Signals
a. Input signal
(1) M1 EM (M1 to PRCB)
M1 fault detection signal
[H]: Abnormal rotation (PLL lock has been
released for 2 to 3 seconds or longer.)
[L]: Normal rotation
b. Output signal
(1) M1 CONT (PRCB to M1)
M1 drive control signal.
[H]: M1 ON
[L]: M1 OFF
2. Signals
a. Input signal
(1) M2 EN (M2 to PRCB)
M2 motor encoder signal
b. Output signals
(1) M2 CONT (PRCB to M2)
M2 drive control signal (PCOM)
[L]: M2 ON
[H]: M2 OFF
(2) M2 F/R (PRCB to M4)
M2 rotational direction switchover signal
[H]: CCW (relative to motor shaft)
[L]: CW (relative to motor shaft)
2 - B - 2
READ SECTION
[1] Composition
Optics rail (R)
Slit glass
READ SECTION
Scanner drive wire
Exposure unit
V-mirror unit
(2nd and 3rd mirrors)
2 UNIT EXPLANATION
Scanner cooling fan (FM7)
[2] Mechanisms
Mechanism
Light source
Exposure
Scanning
Lamp power supply
Optics cooling
CCD unit
A/D converter
board
Method
Xenon lamp
Light source shift slit exposure
Platen original scanning: 1st, 2nd, and 3rd mirrors are shifted.
RADF original scanning: Original is moved with light source held
stationary.
Lamp cord
Cooling fan
2 - C - 1
READ SECTION
[3] M13 (Scanner Drive) Control
2 UNIT EXPLANATION
M13 CLK
M13 F/R
M13 CSEL
M13 V0
M13 V1
M13 V2
PS5
PS7
PS6
PS4
PRCB SCDB DCPS1
M13 DRIVE U
M13 DRIVE V
M13 DRIVE W
5VDC
PS5
SGND
PS7
5VDC
PS6
SGND
PS4
M13
PS5
PS7
PS6
PS4
24VDC
PGND
DCPS2
5VDC
SGND
M13 (scanner drive) is driven by the SCDB (scanner
drive board) and is controlled by the PRCB (printer
control board).
Related signals are PS4 (scanner reverse), PS5
(scanner HP), PS6 (original HP), and PS7 (ADF
brake).
1. Operation
a. Operation of M13
M13 is a 3-phase stepping motor driven using
the 3-phase bipolar constant-current drive
method. The motor is turned ON/OFF by
supplying/stopping clock pulses.
b. Movement speed of the exposure unit
Scanning speed
Operation mode
Scan
Movement speed
370 mm/sec (400 dpi, 1:1)
164.4 mm/sec (600 dpi,
1:1)
Forward
Home position
569.23 mm/sec
92.5 mm/sec
search
2 - C - 2
c. Positions of sensors
Paper exit side Paper feed side
PS7 PS5 PS6 PS4
ADF break Scanner HP
PS7 PS5
READ SECTION
White correction
d. Exposure unit home position search
If the exposure unit is not at the home position
when the main switch is turned ON or when the
START PRINT button is pressed, the home
position is searched for in the follo wing manner:
(1) When the exposure unit is on the paper exit side
with respect to the home position
When the exposure unit is at PS7 (ADF brake)
(PS7 is ON), it moves forward at a low speed
until PS5 (scanner HP) turns ON and OFF again,
then it stops. Next the exposure unit moves
backward until PS5 turns ON again.
When the exposure unit is between PS7 and PS5,
it moves backward until PS7 turns ON before
moving forward as mentioned above.
(2) When the exposure unit is on the paper feed side
When the exposure unit is at PS5 (PS5 is ON), it
moves forward at a low speed until PS5 turns
OFF before moving as discussed in (1) above.
When the exposure unit is on the paper feed side
with respect to PS5, it stops after PS5 turns ON
and moves forward before moving as discussed
in (1) above.
400dpi shading correction
600dpi shading correction
2 UNIT EXPLANATION
f. ADF copy operation
PS7 PS5
Original read
position
e. Read with shading correction
When L1 (exposure lamp) is turned ON, the
exposure unit mov es toward the paper e xit side,
thus reading the light reflected by the white
reference plate installed underneath the glass
stopper plate and performing white correction.
Then, L1 is turned OFF for black correction,
returning to the home position. Shading correction
is performed at 400 dpi and 600dpi.
g. Platen copy operation
Scanner HP
PS5 PS6 PS4
AE scan
Original area judgment
Exposure scan
Home position search
Original HP
Scanner
return
2 - C - 3
READ SECTION
2. Signals
a. PRCB input signals
(1) PS4 (PS4 to SCDB to PRCB)
Scanner reverse detection signal.
In the platen mode, the return position of the
exposure unit is detected on the original's leading
edge side.
[L]: The exposure unit is detected.
[H]: The exposure unit is not detected.
(2) PS5 (PS5 to SCDB to PRCB)
Scanner home position detection signal.
The reference position for the home position of
2 UNIT EXPLANATION
the exposure unit is detected.
[L]: The exposure unit is detected.
[H]: The exposure unit is not detected.
(3) PS6 (PS6 to SCDB to PRCB)
Original home position detection signal.
In the platen mode, the reference position for the
original's leading edge is detected.
[L]: The exposure unit is detected.
[H]: The exposure unit is not detected.
(4) PS7 (PS7 to SCDB to PRCB)
ADF brake detection signal.
In the DF mode, the exposure reference position
is detected.
[L]: The exposure unit is detected.
[H]: The exposure unit is not detected.
b. PRCB output signals
(1) M13 CLK (PRCB to SCDB)
Clock signal for M13
(2) M13 F/R (PRCB to SCDB)
M13 rotational direction switchover signal.
[L]: The exposure unit is moved toward the
paper exit side.
[H]: The exposure unit is moved toward the
paper feed side.
(3) M13 CSEL (PRCB to SCDB)
M13 excitation switchover signal.
[L]: 2-/3-phase excitation
[H]: 2-phase excitation
(4) M13 V0 to V2 (PRCB to SCDB)
M13 excitation current switchover signal.
c. OPDB output signals
(1) M13 DRIVE, U, V, W (SCDB to M13)
M13 drive control signals.
These signals are used to control rotation of M13.
By supplying and stopping clock pulses, the motor
is turned ON/OFF and the rotational direction is
switched.
[4] Exposure control
L1 CONT
PRCB SCDB
24VDC
L1 CONT
L1 (exposure lamp) is driven by the L1 INVB (L1
inverter) and is controlled by the PRCB (printer control
board) via the SCDB (scanner drive board).
1. Operation
L1 is a xenon lamp driven by the inverter circuit.
The xenon lamp can emit a constant quantity of
light and generates less heat than other lamps,
requiring neither light quantity controller circuit
nor thermal protector circuit that have been used
in the conventional machines. However, since
L1 is held lit when the exposure unit is
nonoperational in the DF mode, a FM7 (scanner
cooling) is installed in the read section.
2. Signals
a. Output signals
(1) L1 CONT (PRCB to SCDB to L1 INVB)
L1 ON/OFF control signal.
[L]: L1 ON
[H]: L1 OFF
L1 INVB
24VDC
PGND
DCPS2
LV
HV
L1
2 - C - 4
READ SECTION
5VDC
PS62
SGND
PS63
PS64
PS65
PS66
PS67
PS68
PRCB ICB IFB
PS62
PS63
PS64
PS65
PS66
PS67
PS68
DCPS1
5VDC
SGND
[5] Original Read Control
TCK1
SGND
TCK2
SGND
RCK1
SGND
RCK1
SGND
TG
CLMP
S CK
S IN
S LD
MD0
MD1
MD2
S LP
SGND
AD CK
APR
OD0
OD8
SGND
ED0
ED3
ICB IFB ICB
[6] APS Control
CCD
ADB
2 UNIT EXPLANATION
Original read control is performed by the ADB (A/D
converter board) and CCD sensor installed in the ADB.
1. Operation
The light reflected by the exposed original is input
to the CCD sensor through the lens. The analog
voltage corresponding to the quantity of input light
is A/D-converted in the ADB, being output to the
ICB (image control board).
a. Original read
The original read timing is as follows:
(1) Platen mode
Specified interval after exposure unit turns PS6
(original HP) ON.
(2) DF mode
After lapse of the specified time after the original's
leading edge turns ON PS308 (Original).
The APS method used in the platen mode is different
from that used in the DF mode.
The signal read by the APS sensor or the original size
detection sensor of the RADF is processed by the CB
(control board).
1. Operation
a. APS detection
(1) DF mode
The original size is detected according to the
combination of ON/OFF states of PS302 (original
size detection 1) and PS303 (original size
detection 2) and the resistance value of VR301
(original size detection).
2 - C - 5
READ SECTION
(2) Platen mode
The paper size is detected according to the
combination of ON/OFF states of PS62 (APS 1),
PS63 (APS 2), PS64 (APS 3), PS65 (APS 4),
PS66 (APS 5), PS67 (APS 6), and PS68 (APS
7).
The APS sensor consists of LEDs and
photosensors. Lights emitted from the LEDs is
reflected by the original and received by
photosensors.
2 UNIT EXPLANATION
Paper exit side
Relationships between sensors and original sizes
are as follows:
Sensor
Paper
size
B5R
B5
B4
A4R
A4
A3
8.5 x 11R
8.5 x 11
8.5 x 14
11x 17
Min. size
PS63
PS62 PS68
PS66
PS64
PS67
PS65
Photo sensor
LED
PS62 PS63 PS64 PS65 PS66 PS67 PS68
ON
OFF
b. APS detection timing
The APS detection timing differs between the
platen mode and DF mode.
(1) DF mode
When the DF mode is selected or original is set
on the RADF original feed tray, APS detection
takes place using PS302 (original size detection
1), PS303 (original size detection 2), and VR301
(original size detection).
(2) Platen mode
When RADF is closed and PS315 (APS timing)
turns ON, APS detection takes place using PS62
to PS68.
2. Signals
a. Input signals
(1) PS62 (PS62 to ICB IFB)
Paper size detection signal
[L]: Paper is detected.
[H]: Paper is not detected.
(2) PS63(PS63 to ICB IFB)
Paper size detection signal
[L]: Paper is detected.
[H]: Paper is not detected.
(3) PS64 (PS64 to ICB IFB)
Paper size detection signal
[L]: Paper is detected.
[H]: Paper is not detected.
(4) PS65 (PS65 to ICB IFB)
Paper size detection signal
[L]: Paper is detected.
[H]: Paper is not detected.
(5) PS66 (PS66 to ICB IFB)
Paper size detection signal
[L]: Paper is detected.
[H]: Paper is not detected.
(6) PS67 (PS67 to ICB IFB)
Paper size detection signal
[L]: Paper is detected.
[H]: Paper is not detected.
(7) PS68 (PS68 to ICB IFB)
Paper size detection signal
[L]: Paper is detected.
[H]: Paper is not detected.
2 - C - 6
READ SECTION
[7] AE Control
ICB IFB ICB
TCK1
SGND
TCK2
SGND
RCK1
SGND
RCK1
SGND
TG
CLMP
S CK
S IN
S LD
MD0
MD1
MD2
S LP
SGND
AD CK
APR
OD0
OD8
SGND
ED0
ED3
CCD
ADB
(2) DF mode
The image at the leading edge of the original is
read when the PRINT START button is pressed.
The read data is used to measure the image
density on the original.
<AE sampling area>
(1) Main scanning direction
• 10-mm area inside the original detected by
APS
(2) Sub scanning direction
Range between 2mm to 7.3mm from the leading
edge of the original.
2 UNIT EXPLANATION
The CCD sensor detects the image density on an
original during AE scanning to select the optimum copy
gamma correction curve.
AE processing is controlled by the ICB (image control
board).
1. Operation
a. AE detection
(1) Platen mode
The image density on an original is measured
while the exposure unit moves from the home
position to the leading edge of the original after
depression of the START PRINT button.
<AE sampling area>
(1) When ADF is closed
10mm inside perimeter of original size detected
by APS.
(2) When ADF is opened
Entire original area detected by forward scanning.
2 - C - 7
WRITE UNIT
[1] Composition
WRITE UNIT
Cylindrical lens 1
Index sensor board
2nd mirror
[2] Mechanisms
Mechanism
*1 Scan
Light source
*2 Positioning
*3 Laser beam
combining
fθ lens 2
fθ lens 1
Collimator lens unit 1
Laser driver board LD1
Method
Polygon mirror
Rotational speed:
21,850.4 rpm (400dpi)
32,775.6 rpm (600dpi)
Laser diodes (two)
(Output: Max. 20 mW)
Index sensor
Fine adjustment prism
Beam combining prism
Polygon mirror
Cylindrical lens 2
3rd mirror
Collimator lens unit 2
Beam combining prism
CY2 lens
3rd mirror
Polygon
mirror
Laser driver board LD2
Semiconductor
laser LD2
Compression prism
2 UNIT EXPLANATION
Semiconductor laser
LD1
Collimator
lens unit
Beam
combining
prism
CY1 lens
*1 Path of laser light
The light output from semiconductor laser is
radiated onto the OPC drum via the collimator
lens, compression prism, fine adjustment prism,
beam combining prism, cylindrical lens 1, polygon
mirror,fθ lens 1, fθ lens 2, second mirror,
cylindrical lens 2, and third mirror.
2 - D - 1
Glass cover
Index mirror
Index sensor
OPC drum
2nd mirror
fθ lens 2
fθ lens 1
WRITE UNIT
*2 Positioning
Each laser beam is positioned by the
compression prism and fine adjustment prism.
*3 Laser beam combining
Two laser beams output at right angle to each
other are redirected in the same direction using
the beam combining prism.
2 UNIT EXPLANATION
Semiconductor laser 1
Laser 1 beam passes
Laser 2 beam
reflected
Beam combining
prism
Semiconductor
laser 2
[3] M17 (Polygon ) Control
M17 is driven by the PMDB (polygon driver board)
and is controlled by the PRCB (printer control board).
M17 EM
M17 CLK
M17 CONT
PRCB
24VDC
PGND
DCPS2 PMDB
1. Operation
a. Explanation of operation
M17 is a 3-phase brushless DC motor which is
driven by the 3-phase bipolar method. The
current flowing through the coil is switched
according to the position of the rotor detected by
the position sensor (magnetic sensor) in the
motor.
This motor rotates the polygon mirror to scan the
laser beams from LDB1 and 2 (laser driver boards
1 and 2) in the axial direction of the drum. Its
rotation is held constant by PLL control.
b. Rotational speed
M17 is powered by 24 VDC and its speed is as
follows:
SGND
24VDC
M17 MAG A’
M17 MAG A
M17 MAG B’
M17 MAG B
M17 MAG C’
M17 MAG C
M17 DRIVE C
M17 DRIVE B
M17 DRIVE A
M17
2 - D - 2
Machine state Rotational speed
400 dpi 21,850.4 rpm
600 dpi 32,775,6 rpm
2. Signals
a. PRCB input signals
(1) M17 EM (PMDB to PRCB)
This signal indicates the clock synchronization
state of M17.
[L]: Synchronous (normal)
[H]: Asynchronous (abnormal)
b. PRCB output signals
(1) M17 CONT (PRCB to PMDB)
This signal turns ON/OFF M17.
[L]: M17 ON
[H]: M17 OFF
(2) M17 CLK (PRCB to PMDB)
This is a reference clock signal f or PLL-controlling
M17 in PMDB.
c. PMDB input signals
(1) M17 MAG A/A’ (M17 to PMDB)
(2) M17 MAG B/B’ (M17 to PMDB)
(3) M17 MAG C/C’ (M17 to PMDB)
Output signals from the position sensor (magnetic
sensor) incorporated in M17.
The PMDB detects the position of the motor
rotator using these signals, switching among
outputs, M17 DRIVE A to C.
d. PMDB output signals
(1) DRIVE A to C (PMDB to M17)
M17 drive signals.
M5 DRIVE A to C supplies the corresponding
voltages to M17. Pulses of the voltages
applied to M17 are shown below. The pulse
widths of the PMDB output signals change as
shown below depending on the state of M17
rotation, causing the effective values of the
voltages supplied to M17. Thus, the M17
speed can be controlled.
WRITE UNIT
2 UNIT EXPLANATION
M5 DRIVE A
M5 DRIVE B
M5 DRIVE C
2 - D - 3
WRITE UNIT
[4] Image Write Control
2 UNIT EXPLANATION
M24 PWR A
M24 PWR B
M24 DRIVE A
M24 DRIVE A’
M24 DRIVE B
M24 DRIVE B’
5VDC
SGND
M INDEX 1
SGND
M INDEX 2
SGND
S INDEX1
SGND
S INDEX 2
SGND
HL VL
IPR
SGND
M24
INDEXSB
ADB
ICB
5VDC
SGND
DCPS1
24VDC
PGND
DCPS2
The analog image data from the CCD sensor is A/Dconverted by the ADB (A/D conv erter board), then sent
to the ICB (image control board) for data processing.
The processed image data is converted into a laser
beam according to the control signal received from
the ICB through the ICB IFB (ICB I/F board), then the
beam is radiated onto the drum surface. Two lasers
5VDC
SGND
LD1 SH
LD1 ENB
LD1 VIDEO
SGND
LD1 ALM
LD1DCLK
LD1 DI
LD1 LD
LD1 PR
LDB1
5VDC
SGND
LD2 SH
LD2 ENB
LD2 VIDEO
SGND
LD2 ALM
LD2 DCLK
LD2 LD
LD2 AD
LD2 PR
LDB2ICB IFB
are provided to write two lines of image data per scan.
The write start position is detected by the INDXSB
(index sensor board). The ICB has an E-RDH
(electronic RDH processing) function to store digitized
data. Various editing functions can be performed
based on this data.
2 - D - 4
WRITE UNIT
1. Operation
a. Image processing
The following processing is performed by the ICB
(image control board):
(1) AOC (Auto Offset Control)
During shading correction, a read operation takes
place while L1 (exposure lamp) is OFF, and the
analog offset voltage of the output from the CCD
sensor is automatically adjusted so that the
resulting level is the lower limit of the A/D
converter.
(2) AGC (Auto Gain Control)
During shading correction, the white reference
plate is read, and the amplification of the analog
output from the CCD sensor is automatically
adjusted so that the resulting level is the upper
of the A/D converter.
(3) Shading correction
<Timing>
• When SW1 (main switch) is turned ON
(4) Brightness/density conversion
(5) EE processing
(6) Text/dot pattern judgment
(7) Filtering/magnification change processing
(8) Magnification change processing
(9) Copy gamma correction
(10)Skew correction
(11)Error diffusion processing
(12)Data compression
(13)Write density control
b. Write
The ICB (image control board) sends image data
on a pixel basis to LDB1 and LDB2 according to
the control signals from the PRCB (printer control
board).
LDB1 and LDB2 cause the lasers to emit for a
period corresponding to the image data. This laser light is radiated onto the drum surface.
(1) MPC (Maximum Power Control)
ICB informs LDB1 and LDB2 of the maximum
output value and sets that value for the laser
beam emission. LDB1 and LDB2 store this setting
value and maintain the quantity of the laser beam
emission using the APC (Auto Power Control).
<MPC timing>
a) When SW1 (main switch) is turned ON
(2) APC (Auto Power Control)
The ICB outputs an APC start instruction to the
LDB at the following timing, after MPC is set.
<APC timing>
a) The LDB1 and LDB2 automatically monitor the
laser drive current one line at a time, and
controls it so that the light intensity remains
the MPC value.
(3) Write timing
a) Main scanning direction
Using INDEX signal from INDXSB, determines
the laser write reference position for each scan
in the drum rotation direction, and writes the
image to copy paper using the paper position
information derived from the paper position
detection by PS1(paper mis-centering).
INDEX
Laser
output 1
Laser
output 2
ab c d e
Symbol
a
b
b-c
c-d
d-e
Image area
1st scanning 2nd scanning
Description
Laser goes ON for first scan
Index sensor goes ON.
The timing at the left is controlled
by counting the LD1 IRCLK and
LD2 IRCLK signals. It differs
depending on the document size.
b) Sub scanning direction
Specified interval after PS44 (registration)
detects the tip of the copy paper.
(4) Laser beam position correction
a) Main scanning direction
The index sensor detects the deviation of the
positions of the two beams. This error is
corrected by changing the timing of the light
emission from the laser.
b) Sub scanning direction
The index sensor detects the deviation of the
positions of two beams in order to change the
angle of the fine adjustment prism of the LD1
laser using M24 (laser correction), thus adjusting the vertical angle of the beam.
2 UNIT EXPLANATION
2 - D - 5
WRITE UNIT
2. Signals
a. ICB IFB input signals
(1) M INDEX 1, 2 (INDEXSB to ICB IFB)
This is an index signal used to detect deviation
of vertical scanning.
(2) S INDEX 1, 2 (INDEXSB to ICB IFB)
This is an index signal used to detect deviation
of horizontal scanning.
(3) IPR (INDEXSB to ICB IFB)
This signal monitors the INDEXSB power supply .
[H]: Normal
[L]: Abnormal
2 UNIT EXPLANATION
(4) LD1 ALM (LDB1 to ICB IFB)
This signal indicates the state of the LD1 laser
drive current.
[H]: Normal
[L]: Abnormal
(5) LD1 PR (LDB1 to ICB IFB)
LD1 power supply monitor signal.
[H]: Normal
[L]: Abnormal
(6) LD2 ALM (LDB2 to ICB IFB)
This signal indicates the state of the LD2 laser
drive current.
[H]: Normal
[L]: Abnormal
(7) LD2 PR (LDB2 -> ICB IFB)
LD2 power supply monitor signal.
[H]: Normal
[L]: Abnormal
b. ICB IFB output signals
(1) M24 PWR A (ICB IFB to M24)
M24 A-phase drive signal.
(2) M24 PWR B (ICB IFB to M24)
M24 B-phase drive signal.
(3) M24 DRIVE A/A'(ICB IFB to M24)
M24 A-phase drive pulse signal.
(4) M24 DRIVE B/B' (ICB IFB to M24)
M24 B-phase drive pulse signal.
(5) LD1 SH (ICB IFB to LDB1)
One scan line equivalent APC sampling signal.
(6) LD1 ENB (ICB IFB to LDB1)
Laser APC function ON/OFF control signal.
Laser beam emission stops when it is OFF.
(7) LD2 SH (ICB IFB to LDB2)
One scan line equivalent APC sampling signal.
(8) LD2 ENB (ICB IFB to LDB2)
Laser APC function ON/OFF control signal.
Laser beam emission stops when it is OFF.
(9) LD1 VIDEO (ICB IFB to LDB1)
LD1 laser image signal.
(10)LD2 VIDEO (ICB IFB to LDB2)
LD2 laser image signal.
(11)LD1 DCLK (ICB IFB to LDB1)
LD1 clock signal for MPC value data transmission.
(12) LD1 DI (ICB IFB to LDB1)
LD1 data signal for MPC.
(13) LD1 AD (ICB IFB to LDB1)
LD1 MPC value storage command signal.
(14) LD2 DCLK (ICB IFB to LDB2)
LD2 clock signal for MPC value data transmission.
(15) LD2 DI (ICB IFB to LDB2)
LD2 data signal for MPC.
(16) LD2 AD (ICB IFB to LDB2)
LD2 MPC value storage command signal.
2 - D - 6
DRUM UNIT
[1] Composition
DRUM UNIT
Charging corona unit
Developing unit
Separation claws
Cleaning/toner recycle unit
Cleaning/toner recycle unit
[2] Mechanisms
Mechanism
Carriage support
PCL/TSL
*1 Auxiliary separa-
tion
*2 Conveyance
assistance
PCL
Method
Fixed rail
LED
Separation claws
Ratchet wheel
Charging corona unit
TSL
2 UNIT EXPLANATION
Separation claw solenoid
Developing unit
Transfer and separation corona unit
mechanism slides the separation claws about
5 mm back and forth in parallel with the drum
surface.
Separation claw
Separation
claw
solenoid(SD4)
The drum unit is an integral assembly consisting of a
drum, charging corona unit, developing unit, cleaning
unit, toner recycle unit, PCL, and separation claws.
*1 Auxiliary separation
• To prevent paper jamming, three separation
claws are used to separate paper from the
drum forcibly. These separation claws are
pressed against the drum or detached from it
by turning ON/OFF the separation claw
solenoid (SD4).
• To prevent a specific part of image copied
paper from being stained and to prevent the
drum from being scratched, the swing
*2 Conveyance assistance
The thick paper conveyance ability has been
improved by the use of ratchets.
2 - E - 1
DRUM UNIT
[3] Separation Claw Control
24VDC
SD4 DRIVE
DCDB
SD4 CONT
M2CONT
M2EM
24VDC
PGND
PRCB
24VDC
DCPS2
MS2 MS1
PGND
2 UNIT EXPLANATION
Separation claws are driven by SD4 (separation claw
drive solenoid). Separation claws are slid by M2 (main).
SD4 is controlled by the PRCB (printer control board)
via the DCDB (DC drive board).
1. Operation
a. Separation claw ON/OFF control
SD4 is a pull-type solenoid powered by 24 VDC .
It turns ON to press separation claws against the
drum to help image copied paper separate.
(1) SD4 operation timing
SD4 turns ON after a lapse of specified time from
turning ON of PS45 (leading edge detection). It
turns OFF after a lapse of the time set by the
PRCB timer.
b. Separation claw swing control
Separation claws are swung by M2 (main) via
the cam mechanism.
2. Signals
a. CB output signal
(1) SD4 CONT (CB to DCDB)
SD4 drive control signal.
[L]: SD4 ON
[H]: SD4 OFF
b. DCDB output signal
(1) SD4 DRIVE (DCDB to SD4)
SD4 drive control signal.
[L]: SD4 ON
[H]: SD4 OFF
SD4
M2
[4] Paper Guide Plate Control
GP CONT
PRCB
24VDC
PGND
DCPS2
ADUSDB
To prevent toner from adhering to the paper guide
plate, a constant voltage is applied to the paper guide
plate. This voltage is supplied from HV2 (high v oltage
unit 2) and is controlled by the serial data sent from
the PRCB (printer control board) via the ADUSDB
(ADU frame control board). When the front door of
this machine opens or closes, MS1 (interlock 1) or
MS2 (interlock 2) operates to interrupt the DC power
supply to HV2, stopping the voltage application to the
paper guide plate.
1. Operation
a. ON/OFF timing
Turning ON/OFF in sync with M2 (drum)
b. Applied voltage
-500 VDC
2. Signal
a. Output signal
(1) GP CONT (ADUSDB to HV2)
This signal controls turning ON/OFF the voltage
application to paper guide plate.
[L]: Voltage applied
[H]: Voltage not applied
GP
HV2
2 - E - 2
DRUM UNIT
[5] Drum Potential Control
DPS DRIVE A
DPS DRIVE B
DPS ANG 1
DPS ANG 2
DPSB
PRCB
DCPS2
DPS ANG
SGND
24VDC
PGND
The drum potential is detected by the DPS (Drum
Potential Sensor) and send the PRCB (printer control
board) via the DPSB (drum potential sensor board).
1. Operation
Drum potential control is performed to keep the
drum surface potential constant and maintain
image quality regardless of the usage
environment or the number of copies.
(1) Method
The image is created on the drum surface by the
difference in the exposure potential and
developing bias. A patch is created with laser
PWM maximum.
The developing bias is corrected so that the
difference between the after exposure potential
(solid black area) and the developing bias is
always 500V and the charging current and the
grid voltage are corrected so that the difference
between the before exposure potential and
developing bias is 150V.
(2) Timing
a) When the fixing temperature is lower than 50°C
at power ON.
b) At the end of job after every 5,000 copies.
DPS
2. Signals
a. PRCB Input signals
(1) DPS ANG (DPSB to PRCB)
Analog signal corresponding to the drum
charging potential.
b. DPSB Input signals
(1) DPS ANG 1 and 2(DPS to DPSB)
Analog signal corresponding to the drum
charging potential.
c. DPSB output signals
(1) DPS DRIVE A and B(DPSB to DPS)
DPS(drum potential) drive signal.
2 UNIT EXPLANATION
2 - E - 3
DRUM UNIT
[6] HTR1 (drum heater) Control
12VDC
5VDC
DRUM TEMP
AGND
TH5 ANG1
TH5 ANG2
TH5
12VDC
5VDC
SGND
DCPS1
2 UNIT EXPLANATION
AC(H)
AC(C)
The drum is heated by HTR1 (drum heater). The
PRCB (printer control board) detects the drum
temperature with TH5 (drum temperature sensor) and
controls HTR1 through ACDB (AC drive board). TH5
is a sensor that changes resistance according to the
detected temperature. Therefore, its value is
converted to voltage by DTSB (drum temperature
sensor board) and output to PRCB.
1. Operation
a. Temperature Control
HTR1 is normally maintained at 30°C and the
temperature is increased only when humidity is
high. When warming up under high humidity , the
drum is rotated after the drum temperature
reaches a specified value and then drum potential
control, Dmax control, and gradation correction
control are performed. When warm up completes,
HTR1 is turned ON/OFF to maintain the drum
temperature constant. Under high humidity, the
temperature is raised to 45°C every 30 minutes
and then returned to specified temperature to
prevent dew condensation.
b. Error detection
HTR1 is equipped with self recover type
thermostat to prevent abnormal increase in drum
temperature. The thermostat turns off at 70°C.
HTR1 CONT
PRCB
HTR1 CONT
HTR1 DRIVE
ACDB
DTSB
HTR1
2. Signals
a. PRCB input signal
(1) DRUM TEMP (TH5 to DTSB to PRCB)
Drum temperature signal. The relationship
between drum temperature and output voltage
is linear.
b. PRCB output signal
(1) HTR1 CONT (PRCB to ACDB to HTR1)
Drum heater ON/OFF control signal
c. ACDB output signal
(1) HTR1 CONT (DTSB to HTR1)
Drum heater ON/OFF control signal
(2) HTR1 DRIVE (DTSB to HTR1)
Drum heater drive power supply line
2 - E - 4
CORONA UNIT SECTION
[1] Composition
CORONA UNIT SECTION
<Charging corona unit>
Charging corona unit
Charging
wire cleaning
motor (M23)
Charging
wire cleaning
material
[2] Mechanisms
Mechanism
*1 Charging
Scorotron (DC negative
corona discharge). Discharge
wire: Tungsten, 0.06 mm dia.
(gold-plated skin path: with
automatic wire cleaner). Grid
control: Gold-plated stainless
plate
*2 Toner
transfer
DC positive corona discharge.
Discharge wire: Oxide film
tungsten, 0.06 mm dia., with
automatic wire cleaner.
Toner
detach
AC/DC corona discharge.
Discharge wire: Oxide film
tungsten, 0.06 mm dia., with
automatic wire cleaner
*1 Cleaning the charging wire
The charging corona unit has wire cleaning pads.
The charging wire cleaning pad drive motor
moves the charging wire cleaning pad back and
forth, removing toner and dirt from the wires.
Method
PCL
<Transfer and separation corona unit>
Transfer entrance
guide plate
Plunging prevention plate
Charging
wire
Guide rollers
Transfer
corona unit
Separation corona unit
Charging wire
cleaning material
*2 Cleaning the transfer and separation wires
The transfer and separation wire unit has a wire
cleaner. The transfer and separation wire
cleaning pads drive motor moves the transfer and
separation wire cleaning pads back and forth,
removing toner and dirt from the wires.
Transfer wire
Separation wire cleaning
material
cleaning material
Transfer wire
2 UNIT EXPLANATION
2 - F - 1
Separation wire
CORONA UNIT SECTION
[3] Charging Control
C CONT1
C CONT2
C SHIFT
SGND
G SHIFT
PRCB
2 UNIT EXPLANATION
24VDC
DCPS2 HV1
MS2 MS1
PGND
Charging control is performed using the serial data
sent from the PRCB (printer control board) via the
ADUSDB (ADU stand drive board). HV1 (high voltage
unit 1) is used to apply voltage to the charging wires.
1. Operation
a. Charging
A Scorotron charging method is used. 24 VDC
supplied from DCPS2 is raised to a negative DC
voltage which is then discharged after being
applied to the charging wire.
When the front door of this machine opens or
closes, MS1 (interlock 1) or MS2 (interlock 2)
operates to interrupt the DC power supply to HV1,
stopping the voltage supply to the charging
corona unit and charging grid.
b. Grid voltage
The grid voltage is output from HV1 to the
charging plate.
C SIG
CHARGING
2. Signals
a. Input signal
(1) C SIG (HV1 to PRCB)
Leak or short detection signal.
[L]: Normal
[H]: Abnormal
b. Output signals
(1) C CONT1, 2 (PRCB to HV1)
Charging 1/2 output ON/OF control signal.
[L]: Charging voltage ON
[H]: Charging voltage OFF
(2) C SHIFT (PRCB to HV1)
Charging corona unit output level control signal.
The output to the charging corona unit is
controlled according to the duty ratio of the pulse
(PWM) signal sent from the PRCB.
C SHIFT duty 20% to 80%
Charging output range -500µA to -1900µA
(3) G SHIFT (PRCB to HV1)
Charging grid output level control signal.
The output to the charging grid is controlled
according to the duty ratio of the pulse (PWM)
signal sent from the PRCB.
G SHIFT duty 20% to 80%
Grid voltage output range -400 V to -1000 V
2 - F - 2
CORONA UNIT SECTION
[4] Transfer/Separation Control
24VDC
PGND
DCPS2
MS2 MS1
24VDC
T CONT
S CONT
SEL
T SIG
S SIG
SGND
PGND
ADUSDB
S SHIFT(DC)
S FB(AC)
S FB(DC)
S SHIFT(AC)
T SHIFT
PRCB HV2
The transfer and separation corona unit is controlled
by the PRCB (printer control board) and ADUSDB
(ADU stand drive board) via the HV2 (high voltage
unit 2). Between the the PRCB and ADUSDB, signals
are exchanged using serial data. When the front door
of this machine opens or closes, MS1 (interlock 1) or
MS2 (interlock 2) operates to interrupt the DC power
supply to HV2, stopping the voltage supply to the
transfer and separation corona unit.
SEPARATION
TRANSFER
b. PRCB output signals
(1) T SHIFT (PRCB to HV2)
Transfer corona unit output level control signal.
This signal controls the level of the output to the
transfer corona unit according to the duty ratio of
the pulse (PWM) signal sent from the PRCB.
T SHIFT duty 20% to 80%
Transfer DC output range
70µA to -700µA
(2) S SHIFT (DC) (PRCB to HV2)
Separation corona unit output level control signal.
This signal controls the level of the output (DC
bias component) to the separation corona unit
according to the duty ratio of the pulse (PWM)
signal sent from the PRCB.
S SHIFT duty 20% to 80%
Separation DC output range
0µA to -300µA
(3) S SHIFT (AC) (PRCB to HV2)
Separation corona unit output level control signal.
This signal controls the level of the output (AC
component) to the separation corona unit according to the duty ratio of the pulse (PWM) signal
sent from the PRCB.
2 UNIT EXPLANATION
1. Operation
a. Transfer
Positiv e DC high voltage is used for toner transf er
to the drum surface.
b. Separation
AC high voltage is used for toner separation from
the drum surface.
2. Signals
a. PRCB input signals
(1) S FB (AC) (HV2 to PRCB)
Toner separation (AC) current feedback signal.
This signal monitors the toner separation (AC)
current. It is a 0 to 5V analog signal corresponding to the output level.
(2) S FB (DC) (HV2 to PRCB)
Transfer and separation (DC) current feedback
signal
This signal monitors the toner transfer and
separation (DC) current. It is a 0 to 5V analog
signal corresponding to the output level.
S SHIFT duty 20% to 80%
Separation AC output range
500µA to 1400µA
c. ADUSDB input signals
(1) T SIG (HV2 to ADUSDB)
Leak or short toner transfer abnormality detection signal
[L]: Normal
[H]: Abnor mal
(2) S SIG (HV2 to ADUSDB)
Leak or short toner separation abnormality detection signal
[L]: Normal
[H]: Abnormal
2 - F - 3
CORONA UNIT SECTION
d. ADUSDB output signals
(1) T CONT (ADUSDB to HV2)
Transfer corona unit output ON/OFF control
signal.
[L]: Transfer corona unit ON
[H]: Transfer corona unit OFF
(2) S CONT (ADUSDB to HV2)
Separation corona unit output ON/OFF control
signal.
[L]: Separation corona unit ON
[H]: Separation corona unit OFF
(3) SEL (ADUSDB to HV2)
2 UNIT EXPLANATION
Feedback switchover signal.
This signal determines whether the feedback
signal of the transfer and separation (DC) current
is used for toner separation monitor or toner
transfer monitor.
[L]: Toner separation monitor
[H]: Toner transfer monitor
[5] M23 (Charger Cleaning ) Control
M23 CONT
5VDC
PS41
PS42
PS41
SGND
PS42
M23 F/R
M23 EM
PRCB
12VDC
5VDC
SGND
DCPS1
M23 (charger cleaning ) is a 12V DC motor which is
controlled by the PRCB (printer control board) via the
DCDB (DC drive board). Related signals are PS41
(charging wire cleaning pad HP ) and PS42 (charging
wire cleaning pad limit).
1. Operation
a. Purpose of driving
M23 is used to drive the charging wire cleaning
pad.
b. Operation timing
The charging corona wires are cleaned when the
main switch is turned ON, when the fixing
temperature is lower than 50°C (122°F). They
are also cleaned when the specified copy count
is reached.
* Changeable with 25 mode DIPSW
c. Cleaning operation
The home position of the charging wire cleaning
pad is on the rear side of machine. The charging
wire cleaning pad operates as follows:
M23
DRIVE1
M23
DRIVE2
DCDB
M23
2 - F - 4
Charging wire cleaning
pad HP PS
PS41 PS42
Cleaning (forward)
Cleaning (return)
Home search (forward)
Home search (return)
Charging wire cleaning
pad limit PS
CORONA UNIT SECTION
2. Signals
a. PRCB input signals
(1) M23 EM (DCDB to PRCB)
M23 rotation state detection signal.
[L]: Normal rotation.
[H]: Abnormal rotation
(2) PS41 (PS41 to PRCB)
Charging wire cleaning pad home position
detection signal.
This signal detects the reference position (rear
side) of the charging wire cleaning pad home
position.
[L]: HP detected
[H]: HP not detected
(3) PS42 (PS42 to PRCB)
Charging wire cleaning pad limit detection signal.
This signal detects the front drive limit position
of charging wire cleaning pad.
[L]: Limit position detected
[H]: Limit position not detected
b. CB output signals
(1) M23 CONT (PRCB to DCDB)
M23 drive control signal.
[L]: M23 ON
[H]: M23 OFF
(2) M23 F/R (PRCB to DCDB)
M23 rotational direction signal.
[L]: CW (to the rear end from the home position)
[H]: CCW (to the home position from the rear
end)
c. DCDB output signal
(1) M23 DRIVE1, 2 (DCDB to M23)
M23 drive control signal.
The drive direction of M23 is controlled by
switching the drive current directions of two
signals.
Status
Forward stroke
of cleaning
Return stroke of
cleaning
Stop
M23 DRIVE1 M23 DRIVE2
HL
LH
LL
[6] M18 (Transfer/Separation Cleaning)
Control
M18
DRIVE1
DRIVE2
24VDC
PGND
DCPS2
PRCB
5VDC
SGND
DCPS1
MS2 MS1
5VDC
PS11
SGND
PS12
ADUSDB
M18 (transfer/separation cleaning) is a 24 VDC motor
which is controlled by the PRCB (printer control board)
via the ADUSDB (ADU stand drive board). Between
the PRCB and ADUSDB, signals are exchanged using
serial data. Related signals are PS11 (transfer/
separation wire cleaning pad HP) and PS12 (transfer/
separation wire cleaning pad limit). When the front right
or left door of this machine opens or closes, MS1
(interlock 1) or MS2 (interlock 2) operates to interrupt
the DC power supply to DCDB, stopping the voltage
supply to M18.
1. Operation
a. Purpose of driving
M8 is used to drive the transfer and separation
wire cleaning pads.
b. Operation timing
The transfer and separation wires are cleaned
when the main switch is turned ON, when the
fixing temperature is lower than 50°C, or when
the specified copy count is reached.
* Changeable with 25 mode DIPSW.
M18
M18
PS11
PS12
2 UNIT EXPLANATION
2 - F - 5
CORONA UNIT SECTION
c. Cleaning operation
The home position of the transfer and separation
wire cleaning pads is on the front side of machine. The transfer and separation wire cleaning pads operate as follows:
Tansfer/Separation wire
cleaning pad HP
PS11 PS12
Cleaning (forward)
2 UNIT EXPLANATION
Cleaning (return)
Home search (forward)
Home search (return)
2. Signals
a. PRCB input signals
(1) PS11 (PS11 to PRCB)
T ransf er and separation wire cleaning pads home
position detection signal.
This signal detects the reference position of the
transfer and separation wire cleaning pads home
position (front side).
[L]: HP detected
[H]: HP not detected
(2) PS12 (PS12 to PRCB)
T ransf er and separation wire cleaning pads drive
limit detection signal.
This signal detects the rear limit position of the
transfer and separation wire cleaning pads.
[L]: Limit position detected
[H]: Limit position not detected
b. ADUSDB output signals
(1) M18 DRIVE1, 2 (ADUSDB to M18)
M18 drive control signal.
The drive direction of M18 is controlled by
switching the drive current directions of two
signals.
Tansfer/Separation wire
cleaning pad limit
[7] PCL/TSL Control
24VDC
PGND
DCPS2
PCL CONT
PRCB
LEDs are used for PCL (pre-charging lamp) and TSL
(transfer synchronization lamp). PCL is driven by the
DCDB (DC drive board). TSL is driven b y the ADUSDB
(ADU stand drive board). PCL and TSL are controlled
by the PRCB (printer control board).
1. Operation
PCL is turned ON/OFF in sync with M2 (drum
drive). TSL turns ON after a lapse of specified
time from turning ON of PS45 (leading edge
detection) of the second paper feed section. It
turns OFF after a lapse of specified time from
detection of the trailing edge of copy paper.
2. Signals
a. Output signals
(1) PCL CONT (PRCB to DCDB to PCL)
PCL ON/OFF control signal.
[L]: PCL ON
[H]: PCL OFF
(2) TSL CONT (ADUSDB to TLS)
TSL ON/OFF control signal.
[L]: TSL ON
[H]: TSL OFF
24VDC
PCL CONT
DCDB
24VDC
TSL CONT
ADUSDB
PCL
TSL
Status
Forward stroke
of cleaning
Return stroke of
cleaning
Stop
M18 DRIVE1 M18 DRIVE2
HL
LH
LL
2 - F - 6
DEVELOPING UNIT
[1] Composition
Developing unit cover
Developing sleeve
Splash prevention
sheet (upper)
Developing regulation plate
Developing
sleeve
Agitator
wheel
DEVELOPING UNIT
Agitator screws
[2] Mechanisms
Mechanism Method
Developing 2-component developer
Developing bias DC bias
Developer Main agitator
agitation Auxiliary agitator
1. The developing unit drive motor (M3)
drives the following parts via the gear unit
at the back:
• Developing sleeve
• Agitator wheel
• Agitator screws
2. Flow of developer
The developer inside the developing unit is
supplied to the developing sleeve by the agitator
wheel, and maintained at a constant thickness
by the developing regulation plate (bristle height
regulation plate). The dev eloper remaining on the
developing sleeve is returned to the agitator
screws.
2 UNIT EXPLANATION
Drum
Developing regulation plate
Agitator wheel
Agitator screw
2 - G - 1
DEVELOPING UNIT
[3] M3 (Developing Unit Drive) Control
24VDC
PGND
DCPS2
M3 CONT
M3 CLK
M3 EM
PRCB
M3 (developing) is controlled by the PRCB (printer
control board) and the motor drive power is supplied
by DCPS2 (DC power supply unit 2). When the front
left or right door of this machine opens or closes, MS1
(interlock 1) or MS2 (interlock 2) operates to interrupt
the DC power supply to M3, stopping the voltage
2 UNIT EXPLANATION
supply to the developing sleeve.
MS2 MS1
M3
[4] Developing Bias Control
24VDC
5VDC
SGND
B CONT
B SHIFT
B FB
PRCB
5VDC
SGND
DCPS1
24VDC
24VDC
PGND
DCPS2
MS2 MS1
HV1
The developing bias is controlled by PRCB (printer
control board) via the HV1(high voltage unit 1). When
the front left or right door of this machine opens or
closes, MS1 (interlock 1) or MS2 (interlock 2) operates
to interrupt the DC power supply to HV1, stopping the
voltage supply to the developing sleeve.
BIAS
1. Operation
M3 which is the 24V driven DC motor drives the
developing slee ve and agitator . M3 equipped with
speed control circuit send the rotation error signal
to PRCB when PLL lock is released longer than
the specified time period. M3 starts after the
specified time interval from the start switch is ON,
and stops after the specified time interval from
the charging wire unit stops charging.
2. Signals
a. Input signals
(1) M3 EM (M3 to PRCB)
M3 fault detection signal
[H] Abnormal rotation (when PLL is unlocked
for more than 1.5 seconds)
[L] Normal rotation
b. Output signals
(1) M3 CONT (PRCB to M3)
M3 drive control signal
[L] M3 ON
[H] M3 OFF
1. Operation
The developing bias voltage is applied to the
developing sleeve based on the M2 (drum)
rotation state signal.
2. Signals
a. Input signals
(1) B FB (HV1 to PRCB)
Developing bias voltage feedback signal.
This signal monitors the developing bias v oltage.
It is an 0V to 5V analog signal corresponding to
the output level.
b. Output signals
(1) B CONT (PRCB to HV1)
Developing bias output ON/OFF control signal.
[L]: Developing bias ON
[H]: Developing bias OFF
(2) B SHIFT (PRCB to HV1)
Developing bias output level control signal.
The developing bias output level is controlled
according to the duty ratio of the pulse (PWM)
signal sent from the PRCB.
B SHIFT duty 20% to 80%
Developing bias output range -300 V to-800 V
2 - G - 2
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