Controlling The Laser Activation Timing - Canon imageRUNNER ADVANCE 4551i Service Manual

Polygon motor
PVREQ signal
Laser
BD
Laser A
Laser B
Laser C
Laser D
1: BD signal is generated based on A laser light. Only A laser light reaches BD sensor
on BD PCB and B/C/D laser does not reach.

Controlling the Laser Activation Timing

■ Laser ON/OFF Control
Laser ON/OFF control is dependent on the combination of the laser control signal (A/B laser: CNT0-0/0-1/0-2, C/D laser:
CNT1-0/1-1/1-2) from the DC Controller PCB.
NOTE:
25 ppm machine does not control the C,D laser for 2 beam.
CNT0-0
1
0
1
0
1
0
1
0
CNT1-0
1
0
1
0
1
0
1
0
Control panel key ON
(Start key ON 1 )
Start key ON
STBY INTR
Waiting in FG control
Speed up
Light off Light off
1
BD
Laser A
Laser B
Laser C
Laser D
<A laser/B laser>
Laser control signal
CNT0-1
1
1
0
0
1
1
0
0
<C laser/D laser>
Laser control signal
CNT1-1
1
1
0
0
1
1
0
0
PRINT STBY
Speed down
BD control
Light on Light off
: BD detection/APC control
: AP control
1
CNT0-2
1
1
1
1
0
0
0
0
CNT1-2
1
1
1
1
0
0
0
0
85
2. Technology
Image per 1 line
Laser status
Image data output.
Forced output of the A laser
Forced output of the B laser.
Forced output of the A/B Laser
Output compulsion OFF.
A Laser (APC control)
B Laser (APC control)
Electric discharge: APC reset
Laser status
Image data output.
Forced output of the C laser.
Forced output of the D laser.
Forced output of the C/D laser.
Output compulsion OFF
C Laser (APC control)OFF
D Laser (APC control)OFF
Electric discharge: APC reset