Canon GP200 Service Manual page 79

2. Controlling Pre-Heating
The filament of the scanning lamp is powered
so as to speed up the time in which the intensity
of the scanning lamp reaches its optimum value
after a press on the Copy Start key. (This mecha-
nism is called pre-heating.)
Pre-heating may be full pre-heating or scan-
ning lamp ON pre-heating.
a. Full Pre-Heating
Power is applied during initial rotation.
b. ON Pre-Heating
Power is applied during copying operation.
3. Turning ON/OFF the Scanning
Lamp
The scanning lamp is turned ON/OFF by the
lamp ON signal (FLPWM) of the DC controller
PCB.
The FLPWM signal is sent to the logic circuit
together with MPCLK (pulse signals) generated
by the composite power supply PCB. The logic
circuit uses these two signals to generate the
scanning lamp ON signal, thereby turning ON the
scanning lamp.
COPYRIGHT © 1996 CANON INC.
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4. Controlling the Intensity
control the intensity of the scanning lamp to a
specific level by varying the duty ratio based on
the results of shading automatic correction exe-
cuted in service mode according to the output of
the scanning lamp intensity sensor.
5. Detecting Errors
presence of the lamp ON signal, the scanning
lamp ON circuit detects the condition to generate
the error detection signal (PRTCT) to the CPU.
lamp OFF signal (FLOFF) without waiting for a
command from the DC controller.
CANON GP215/200 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
3. OPERATIONS AND TIMING
The FLPWM signal is a pulse signal used to
If the scanning lamp fails to turn ON in the
In response, the CPU generates the scanning
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