Canon NP6012 Service Manual page 65

D. Controlling the Scanning
Lamp
1. Outline
Figure 3-305 shows the circuit that con-
trols the scanning lamp (fluorescent lamp;
FL1); the circuit has the following functions:
¢ controls pre-heating of the scanning
lamp.
turns on and off the scanning lamp.
* controls the intensity of the scanning
lamp.
* automatically corrects the intensity of
the scanning Jamp.
The copier's scanning lamp is a fluores-
cent lamp.
Scanning lamp
In consideration of these characteristics
of the fluorescent
lamp, the copier is
equipped with an intensity sensor so that the
originals may be illuminated only after the
intensity of the fluorescent lamp has stabi-
lized.
The copier does not start copying opera-
tion until the intensity of the fluorescent lamp
has been checked and verified that it has
reached a specific value.
sity sensor PCB
=)
Seanning lam
heaters (a2
VR101
+5V
Intensity sil
int a
Pre-heat
voltage
control
circuit
| ir Pre-heat
transformer
(7402)
Fluorescent
lamp driver
FLON*_
FLPRHT _
=>
DC controlier PCB
Composite power supply PCB
Figure 3-305
3-20 COPYRIGHT © 1995 CANON INC.