Controlling The Laser; Overview - Canon iR C1020 Series Service Manual

7.2 Controlling the Laser

7.2.1 Overview

The laser control is to allow the laser driver to turn the laser diode ON/OFF according to the laser control signals sent from the DC controller.
There are two laser driver PCBs: one is for M/C and the other is for Y/Bk. The configurations of both PCBs are identical.
In the case of the laser driver for M/C
DC controller PCB
+5V
+5V
The DC controller sends the following signals to each laser driver IC (IC1, IC2).
- video signals (VDO, /VDO) for the image formation
- laser control signals (CTRL 0 to 2) for switching the operational mode of the laser driver circuit
- laser light intensity switch signal (LDPWRH) for switching the laser light intensity
The laser driver IC controls the laser according to the combination of the laser control signals.
LDPWRH
LD2CTRL0
LD2CTRL1
LD2CTRL2
VDO21,/VDO21
VDO22,/VDO22
LD2PDOUT
LD1CTRL0
LD1CTRL1
LD1CTRL2
VDO11,/VDO11
VDO12,/VDO12
LD1PDOUT
/BD1I
Laser driver PCB
Cyan laser driver circuit
Light intensity
switching
circuit
LD1
IC2
PD
LD2
C14
Magenta laser driver circuit
LD1
IC1
PD
LD2
C8
F-7-2
Chapter 7
LD2
LD1 BD circuit
0019-5007
7-3