Quenching; Operation - Ricoh FT5540 Service Manual

9. QUENCHING

9.1 OPERATION

The pre-quenching corona (PQC) [A] applies a positive dc corona (5 kilovolts) to neutralize
the negative charge remaining on the drum's surface from the pre-cleaning corona.
Simultaneously, the quenching lamp [B] neutralizes any remaining positive charge on the
drum. Both a lamp and a dc corona are required because the quenching lamp is less effective
against negative charges than positive charges.
The quenching lamp also stabilizes the drum sensitivity from the first cycle by pre-illuminating
the drum.
This machine uses a cold cathode lamp (sometimes called a cold fluorescent tube) as the
quenching lamp. The cold cathode lamp (ac 430 volts, 1.3 watts) consumes less power,
releases less heat, and is brighter. Also, its effective light is in the most sensitive range of the
drum. A plastic filter prevents toner from being deposited on the lamp.
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31 August 1989