COPYRIGHT
©
1998 CANON INC. CANON NP7161/NP7160 REV.0 AUG. 1998 PRINTED IN JAPAN (IMPRIME AU JAPON)

4–3

CHAPTER 4 IMAGE FORMATION SYSTEM

C. Controlling the Intensity of the Scanning Lamp

1. Outline

Figure 4-103 shows the circuit used to control the intensity of the scanning lamp, and the

circuit has the following functions:

1. Turning on/off the scanning lamp

2. Controlling the intensity of the scanning lamp

controlling the light to a specific intensity against fluctuations in power supply voltage

Lamp regulator
PCB
Power supply
PCB
DC controller
PCB
+5V
LMPDR
Scanning lamp
(LA1)
Thermal fuse
(FU1)
J501
-1
-3
J203
-1
-3
J501
-4
-6
J503
-1
-2
-3
-4
-5
J211
-5
-4
-3
-2
-1
J106
-4
-8
-6
AC_24V_ON
J106
-24 J106
-24
J212
-21
-17
-19 Control
circuit
Drive
circuit
LMP_PWM
LMPDT
Error
detection
circuit
Lamp
ON
detection
IC113
IC119
(CPU) RL
+24V

Figure 4-103