Outline - Canon GP605 Service Manual

CHAPTER 3 ORIGINAL EXPOSURE SYSTEM
III . CONTROLLING THE SCANNING LAMP
A.

Outline

The scanning lamp is controlled for the following:
[1] Temperature by a fluorescent lamp heater
[2] Pre-heat voltage
[3] Initial activation
[4] Intensity by a light intensity sensor
Figure 3-301 shows the construction of the mechanisms used to control the scanning lamp.
Difference between
FL-REF and FL-DTCT.
FL-PWM is corrected
based on this data.
When '0' ,the scanner
heater turns on.
J506B
1
HEAT-ON
2
FL-TH
3
0 V
4
5
0 V
6
7
8
9
PRH-PWM
10
FLON
11
0 V
12
FL-PWM
13
When '0', the
fluorescent
lamp turns on.
Pulse signals. Changing the pulse
width increases/decreases the
intensity of light.
Pulse signals. Changing the pulse
width increases/decreases the pre-
heat voltage.
Figure 3-301 Construction of the Control System
3-8
COPYRIGHT © 1999 CANON INC.
Light intensity control PCB
1 2 3 4 5
J853
FL-GAIN
FL-REF
Transformer
6 drive control
FL-CLK
7
FL-ERR
8
PRH-ON
9
10
11
12
13
J1002
Inverter PCB
Voltage to suit the light intensity.
J852
24 V
1
2
GND
3 To light intensity sensor
38 V
4
To temperature sensor/scanner
GND
5
heater
FL-TH
6
1 2 3 4
Fluorescent lamp
J851
heater temperature
Reference intensity
level for comparison
against FL-DTCT.
Relay PCB
J1001
1 2
T1001
Fluorescent
lamp
transformer
Pre-heat
Pre-heat voltage
output
control
Current
Output
detection
control
When '0', pre-heat voltage is applied.
Error detection
Pulse signals used to drive
the transformer (T1001).
CANON GP605/605V REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
FL-DTCT
H5
Temperature
sensor
Activation
J803
voltage
1
2
3
4
5
Scanning
lamp
Light intensity
sensor
Fluorescent heater