Charge Corona Power Pack - Ricoh FT8680 Service Manual

31 July 1995

3.4 CHARGE CORONA POWER PACK

DC Power Supply
Main PCB
The main PCB sends a PWM (Pulse Width Modulation) signal to the charge
corona power pack. According to the PWM ratio, the dc power pack outputs a
high dc voltage to the charge corona wires. The main PCB determines the
PWM ratio based on the process control data.
There is a safety relay (RA303) on the dc drive board which is activated by a
signal from the main PCB. In case of the SC conditions related to the high
voltage devices and the abnormal exposure lamp on, the main PCB turns the
RA303 to cut the power of dc 24 V to the power pack through its contact.
DC Drive PCB
2-21
Door
SW
Drum Current
Detect PCB
DRUM CHARGE
24 V
GND
PWM
TRIG
Charge
Corona P.P.
A171D506.wmf