Ricoh FT8680 Service Manual page 40

DRUM 31 July 1995
2. DRUM
2.1 OVERVIEW
[D]
[E]
[A]
[C]
[B]
[F]
Al
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This model uses an FO-type drum made by applying an urethane resin
coating [A] on an F-type drum [B]. This coating provides a long life and
minimize the white line problems on the half-tone areas.
For the F-type drum, the charge carrying layer [C] is made by the drum
conditioning. Since the FO-type drums are coated after the charge carrying
layer has been made, it is not necessary to perform the drum conditioning at
the new drum installation.
When drum temperature drops below the permissible level, extreme
sensitivity changes occur. Additionally, the temperature changes can cause
condensation. To maintain a constant drum temperature, a drum heater [D]
(100 V 140 W) which is controlled by a thermistor [E] and two thermoswitches
[F] is used.
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