Apc Control - Canon iR6570 series Service Manual

DC controller
MEMO:
1. The laser power is adjusted automatically when the laser unit is replaced.
2. When the manual feed tray is used as the source of paper, the write operation starts when the registration paper sensor (PS29) detects paper.
SERVICE MODE:
DISPLAY> DPOT> LLMT-P
indicates the laser power voltage control value for printer (PDL) imaging.
DISPLAY> DPOT> LLMT
indicates the laser power voltage control value for copier imaging.
DISPLAY> DPOT> LPOWER-P
indicates the result of potential control for the laser intensity used during printer (PDL) imaging.
DISPLAY> DPOT> LPOWER-C
indicates the result of potential control for the laser intensity used during copier imaging.
DISPLAY> MISC> LPOWER
indicates the laser intensity in real time.
ADJUST> LASER> PVE-OFST
used to adjust the laser incident point.
FUNCTION> LASER> POWER
used to turn on laser light.

6.3.2.2 APC Control

The machine executes APC control so that the laser light will remain at a constant level by adjusting the output of the laser diode mounted on the laser
driver.
The control mechanism takes place on the DC control PCB.
The DC controller sends the laser control signal (CTL0=0, CTL1=1) to the laser driver IC on the laser driver PCB.
In response, the laser driver IC sets APC mode, and forces the laser diode (LD) to emit light.
While all this is under way, the laser driver IC monitors the laser diode (LD) by means of a photo diode (PD), and adjusts the output of the laser diode unit
so that the intensity is at a specific level.
J117
1
LD(+) [1]
2
LD(-) [1]
3
GND
4
J121
GND
1
GND
2
LZ-LDPSEL[7]
3
GND
EEPROM 4
CTL1[3]
5
CTL0[2]
6
GND
7
5.5V
8
J113
LWRPD [4]
B2
PCB
DC-CON
J121
CTL0
CTL1
J102
3
Laser
2
drive
1
circuit
J101
9
8
7
6
5
4
3
2
1
Laser driver PCB
F-6-4
Laser Driver
J101
[1]
F-6-5
Laser block
[6]
Laser
Intensity
monitor [5]
Laser unit
Laser write
start sensor (PS28)
5V
PD
LD
Chapter 6
0009-5252
6-5