Drum; Opc Drum Characteristics - Ricoh A219 Service Manual

1. DRUM

1.1 OPC DRUM CHARACTERISTICS

The OPC (Organic Photoconductor) drum used in this copier is small in
diameter (30 mm), ensuring good paper separation. An OPC drum has the
following characteristics.
1. The drum is able to accept a high negative electrical charge in the dark.
(The electrical resistance of a photoconductor is high in the absence of
light.)
2. It dissipates the electrical charge when exposed to light.
(Exposure to light greatly increases the conductivity of a photoconductor.)
3. The amount of charge dissipated is in direct proportion to the intensity of
the light. That is, where stronger light is directed to the photoconductor
surface, a smaller voltage remains on the drum.
4. An OPC drum is less sensitive to changes in temperature (when
compared to selenium F type drums).
5. During the drum's life, drum residual voltage gradually increases and the
photoconductive surface becomes worn. Therefore, some compensation
for these characteristics is required.
SM
CÓPIA NÃO CONTROLADA
2-1
CÓPIA NÃO CONTROLADA
DRUM
A219