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■ Input to the Reversal Amplifier Circuit (if the intensity increased gradually)
Figure 4-109
■ Changes in the Duty Ratio of the FLON signal
Figure 4-110
6. Controlling the Fluorescent Lamp Heater
As the temperature around the scanner increases, the resistance of the fluorescent
lamp thermistor (TH3) lowers, thereby lowering the voltage of the fluorescent lamp
thermal signal (FLTH). Based on the voltage, the fluorescent lamp heater control circuit
on the composite power supply PCB turns on and off the fluorescent lamp heater drive
signal (FLTHON).
You can force the fluorescent heater off by turning off the scanning lamp (fluorescent
lamp) heater switch (SW2) during the months in which the heater is not needed.
COPYRIGHT
©
1997 CANON INC. CANON NP6218 REV. 0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 4 IMAGE FORMATION SYSTEM
4-8
Reference voltage
(4V)
Reference voltage
(4V)
Voltage (V)
Input from intensity
adjustment sensor
Lighter
Darker
Time (t)
"C" "D"
FLON signal 'C'
FLON signal 'D'
OFF
OFF
ON
ON