Scanning Lamp Control - Canon GP160F Service Manual

CHAPTER 3 EXPOSURE SYSTEM
B. Changing the magnification ratio
The magnification ratio in horizontal scanning direction (drum axis direction) is
changed by line skipping (for reducing) when writing the image signal to the line memo-
ry, or double scanning (for enlarging) when reading out from the line memory.
The magnification ratio in the vertical scanning direction is changed by increasing
the speed of the mirror mounts movement (when reducing), or reducing the movement
speed (when enlarging).
C.

Scanning lamp control

This unit's scanning lamp uses a xenon tube.
The ON/OFF control of the scanning lamp is performed by the scanning lamp light-
ing control IC (IC38) which is on the image processor PCB.
Based on the scanning lamps drive signal (LMPON), which is output from the scan-
ning lamp lighting control IC (IC38), the inverter PCB drive circuit comes into operation,
causing 24V to be supplied to the scanning lamp via the scanning lamp lighting circuit.
Image processor
PCB
+24V
Scanning
lamp lighting
control IC
(IC38)
[1] LMPON: Scanning lamp drive signal
Related service mode
Service mode>TEST MODE>5:AGING TEST (Number Key 5)
Scanning lamp lighting, ADF motor operation, oblique line pattern print
3-4
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J207-3
Drive
circuit
[1] LMPON
Figure 3-202
COPYRIGHT © 1999 CANON INC.
Inverter PCB
Scanning
lamp lighting
circuit
CANON GP160 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Scanning lamp
xenon tube