Ricoh A66 - Drum Charge

2.2.2 Drum Charge
This copier uses a single corona wire system to charge the drum.
The single corona wire applies a negative charge to the drum surface
(–670V is the standard voltage). The honeycombed stainless steel grid plate
[A] makes the corona charge uniform and controls the amount of negative
charge on the drum surface by applying the negative grid bias voltage.
The high voltage supply board [B] gives a constant corona voltage (–5 kV) to
the corona wire, and controls the grid voltage to maintain proper image
density.
The drum potential sensor [C] checks the drum surface voltage. The
machine uses the output to maintain a constant development potential (see
the Process Control section for more details).
The charge fan [D] provides a flow of air through the corona unit in order to
prevent an uneven build up of negative ions. This helps maintain even image
density and keeps the ID sensor [F] clean.
[A]
[B]
[D]
[E]
[F]
[C]
DRUM UNIT
A166/A187/A189 2-26 SM