Controlling The Scanning Lamp; Lamp; Exposure System; Ii. Exposure System - Canon PC920 Service Manual

II. EXPOSURE SYSTEM

A.

Controlling the Scanning Lamp

1. Outline
Figure 3-201 shows the circuit used to control the scanning lamp, and has the following func-
tions:
• Turning on/off the scanning lamp.
• Controlling the intensity of the scanning lamp.
• Monitoring the state (on/off) of the scanning lamp.
(Q101)
Serial
communication
VR107
DC controller PCB
COPYRIGHT © 1999 CANON INC.
Intensity adjustment
(Q900)
signal
PWM_1KHz
Lamp activation
signal
LAMP_ON
Activation detection
signal
LAMP_DETECT
Composite power supply PCB
Figure 3-201
CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 3 EXPOSURE SYSTEM
Rectifying
circuit
9
+
-
4
+
Phase
2 -
control
circuit
7
(HIC001)
Arcing circuit
Rectifying
circuit
Activation detection circuit
Thermal fuse
(FU1)
Scanning lamp
(LA1)
3-9