Drum Charge - Ricoh FT6645 Manual

DRUM UNIT 23 April 1993

2.3 DRUM CHARGE

2.3.1 Overview
[A]
This copier uses a double corona wire scorotron system for drum charge.
Two corona wires are required to give sufficient negative charge on the drum
surface because of a rather high drum speed (330 mm/sec.). The stainless
steel grid plate makes the corona charge uniform and controls the amount of
negative charge on the drum surface by applying the negative grid bias
voltage.
The charge power pack [A] gives a constant corona current to the corona
wires (1100 µA) and bias voltage to the grid plate is automatically controlled
to maintain proper image density according to the change of the OPC drum
potential due to dirty grid plate and charge corona casing.
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