Ricoh FT 4015, Service Manual

Page: 17 / 229

2. CHARGE
2.1 OVERVIEW
This copier uses a single wire scorotron to charge the drum. The corona wire
[A] generates a corona of negative ions when the high voltage supply unit
applies a negative voltage. The stainless steel grid plate [B] ensures that the
drum coating receives a uniform negative charge as it rotates past the corona
unit.
The exhaust fan [C] causes a flow of air above and through the charge
corona section. This prevents an uneven build-up of negative ions that can
cause uneven image density.
An ozone filter [D], which absorbs ozone (O
3
) generated by the charge
corona, is located beside the exhaust fan. The ozone filter decreases in
efficiency over time as it absorbs ozone. The ozone filter should be replaced
every PM cycle (45 k copies).
[A] [B]
A219D505.wmf
[C]
[D]
A219D521.wmf
Det
ailed
Descript
ions
20 December 1996 CHARGE
2-3