Ricoh FT6645 Manual page 55

DRUM UNIT 23 April 1993
2.6 QUENCHING
[A]
In preparation for the next copy cycle, light from the quenching lamp (QL) [A]
neutralizes any charge remaining on the drum.
The quenching lamp consists of a line of 16 LEDs extending across the full
width of the drum.
Yellow colored LEDs are used for QL to reduce ultra violet light which would
cause light fatigue on the OPC drum.
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