Canon 7086 Series Service Manual - page 236
Chapter 6
6-4
F-6-4
Related Service Mode:
- COPIER > ADJUST > LASER > PVE-OFST (laser projection position adjustment)
If you have replaced the DC controller PCB or initialized the RAM on the DC controller PCB, enter the adjustment value.
Setting range: -300 to 300
Note that the laser B move in sync with the laser A.
The laser D move in sync with the laser C.
6.3.2 Controlling the Intensity of Laser Light
6.3.2.1 APC Control
0010-8029
iR7105 / iR7095 / iR7086
The machine uses APC control to make sure that the intensity of laser light remains at a specific level by controlling the output of the laser diode of the laser driver.
For the control, the machine causes the Video controller to send the laser control signal (CTL0a, CTL1a, CTL2a, CTL0b, CTL1b, CTL2b) to the laser drive IC on
the laser driver PCB. As a result, the laser drive IC is set to APC mode, thus forcing the laser diode (LD) to emit light. While the control is under, way, the laser
driver IC uses the photo diode (PD) to monitor the laser diode (LD), adjusting the output of the laser diode until a specific level of intensity is reached.
F-6-5
SERVICE MODE:
COPIER > FUNCTION > LASER > POWER-A, B, C, D (activation for laser power adjustment)
Use this mode to turn on the laser when checking laser activation.
BD PCB
Laser driver
PCB 2
BD
J3701
J1319
J1406
J1317
J1317
J1312
J1313
J1302
J1303
J1406
GND
5V
VIDEO
BD
4
3
2
1
36
6
7
8
Laser driver
PCB 1
Video signal PCB
Sync
signal
generation
Memory
control
36
When laser light
is detected, '0'.
Generates the printer
sync signal based on
CLK-B.
Executes read operation based
on this sync signal.
Front
Setting decreased
Setting increased
Rear
Laser A, C
Laser driver PCB 1
5V
Laser driver IC
PD
LD
Laser driver PCB 2
CNT1a
CNT0a
CNT0b
CNT2a
CNT2b
CNT1b
J1311
Video PCB
CNT1a
CNT0a
CNT0b
CNT2a
CNT2b
CNT1b
J1317
J1406
J1301