Controlling The Intensity Of The Scanning Lamp - Canon 1000 Service Manual

3. OPERATION AND TIMING
E. Controlling the Intensity of the Scanning Lamp
1. Outline
Figure 3-207 shows the circuit used to control the intensity of the scanning lamp, and the circuit has the
following functions:
1.Turns ON/OFF the scanning lamp.
2.Checks ON/OFF state of the scanning lamp.
3.Controls the intensity of the scanning lamp.
• The circuit controls the scanning lamp so that the intensity is kept to a specific level against
fluctuations in voltage.
AC power
supply
J1305A
-7 LAERR
-8 LAON
Reader
controller PCB
-9 LINT
-10
-11
2. Operations
a. Turning ON/OFF the Scanning Lamp
The lamp regulator drive circuit turns OFF when LAON=0, causing the intensity control circuit and then
the scanning lamp (LA5) to turn OFF.
When LAON=1, the lamp regulator drive circuit turns ON to activate the intensity control circuit, thereby
turning ON the scanning lamp (LA5).
3-34
COPYRIGHT © 2001 CANON INC.
Lamp regulator
RelayRL1
J131
-1
Fu
24V
-4
J12
-5
-4
Lamp regulator
drive circuit
-3
24V
-2
Relay
drive circuit
-1
Figure 3-207
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
Rectifier circuit
Switching
circuit
Lamp ON
detection circuit
Timer
circuit
Thermal TP 6
J135 switch (175ºC)
-1
-3
Scanning lamp
LA5