Ricoh FT 4015 Service Manual page 17

20 December 1996 CHARGE
2. CHARGE
2.1 OVERVIEW
[A] [B]
[C]
[D]
A219D505.wmf
A219D521.wmf
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 ) generated by the charge
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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).
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