Controlling The Laser Intensity - Canon ImageRunner 600 Service Manual

CHAPTER 5 LASER EXPOSURE SYSTEM
C.

Controlling the Laser Intensity

The laser is controlled for the following:
[1] Laser power auto control (APC control).
[2] Intensity control to suit the surface potential of the drum.
[2]-1
Selects either laser A EEPROM
or laser B EEPROM for writing.
[2]-2
The activation voltage
determined by potential
control is written into the
EEPROM.
5-10
COPYRIGHT © 1999 CANON INC.
J1107
1 1
9 9
GND
10 10
LD-DT1
11 11
LD-DT2
12 12
SK
13 13
CS
14 14
GND
15 15
GND
16 16
L-RDY-B
17 17
L-RDY-A
18 18
19 19
30 30
When the laser intently is as specified, '1'.
Clock pulses for writing to and reading from the EEPROM.
Figure 5-302 Functional Block Diagram
[1]-1
The intensity is monitored, and a voltage
suited to the intensity is fed back.
[1]-2
The output is controlled so that
the voltage fed back and the
Relay PCB
voltage from the EEPROM will
be identical.
J1714
Laser driver PCB 1
1 2 3 4 5 6
J1301
J1354
To
EEPROM
For laser B
EEPROM
For laser A
EEPROM
Laser driver PCB 2
CANON imageRUNNER 600 REV.1 JAN. 2000 PRINTED IN U.S.A.
Laser B
Intensity monitor
Laser A