Laser On/Off Control; Horizontal Sync Control - Canon LBP6000 Series Service Manual

Chapter 2
*: Unblanking period
The period during which the laser diode is emitted in non-image area.

2.3.2.3 Laser ON/OFF Control

LBP6000 / LBP6000B
In this control, the laser driver turns on/off the laser diode (LD) according to the laser control signal sent from the engine controller.
The following is the circuit diagram of the laser control.
Engine controller
Main controller
The engine controller sends the laser control signal (CNT0, CNT1) for changing the operation mode of the laser to the logic circuit in the laser driver IC, as well as
the video signal (VD0, /VD0) for image formation. The laser driver IC executes laser control according to the combination of the CNT0, CNT1 signals.
The following is the combination of the laser control signal (CNT0, CNT1).
Operation mode
Discharge
Data output
APC
Forced OFF

2.3.2.4 Horizontal Sync Control

LBP6000 / LBP6000B
This is the control to adjust the writing position in the image horizontal direction.
2-6
+3.3V
/BDI
+5V
CNT1
CNT0
Logic PCB
VOD
/VOD
F-2-6
T-2-4
CNT0 CNT1
L L
H H
H L
L H
Laser driver PCB
BD Sensor
PD LD
Comparator
Sample hold
circuit
Drive
circuit
Laser driver IC
Remarks
The capacitor (C1) is discharged.
At normal print
At using APC
At using image mask
0025-1141
C1
0025-1142