Charge Corona Circuit - Ricoh M5 Service Manual

2. Charge Corona Circuit

-.
Main Board
The dc power supply board supplies +22 volts through the interface board and the main board to
CN706-I as the power input of the charge power pack. CN706-3 is the trigger input.
pulse after the sensor plate on the master is detected, the CPU drops CN102-4 from +22 volts to O
volt. This falling edge trigger actuates a hybrid IC within the power pack, which applies about -5600
volts to the charge corona wire.
When the grid reaches about
charge. Therefore, the potential does not fluctuate and an even charge is applied to the master sur-
face.
NOTE: The variable resistor (VR1 ) is set at the factory and should not be adjusted in the field.
Power Pack-Charge
I
I
-820 volts, the varistor begins draining off any excess
3 - 5
25, 1985
May,
On
the 24th