Service manual

2.
DRUM UNIT
2.1 OVERVIEW
The drum unit consists of the drum [A], the charge corona unit [B], the
quenching lamp [C], the drum potential sensor [D], the ID sensor [E], and the
cleaning unit [F].
An organic photoconductor drum (diameter: 80 mm) is used in this machine.
The cleaning unit is at the upper right side of the drum, and faces
downwards. The cleaning unit is a part of the drum unit, and is removed with
and attached to the drum as a unit. This prevents toner from spilling out of
the cleaning unit.
2.1.1 OPC Drum Characteristics
An OPC has the characteristics of:
1. Being 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. Dissipating the electrical charge when exposed to light. (Exposure to
light greatly increases the conductivity of a photoconductor.)
3. Dissipating an amount of charge 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 OPC.
4. Being less sensitive to changes in temperature (when compared to
selenium F type drums).
5. Being less sensitive to changes in rest time (light fatigue). This makes it
unnecessary to compensate development bias voltage for variations in
rest time.
[B]
[C]
[F]
[A]
[D]
[E]
DRUM UNIT
A166/A187/A189 2-24 SM
CÓPIA NÃO CONTROLADA
CÓPIA NÃO CONTROLADA