Ricoh A085, Руководство пользователя, Страница: 273 / 617

2.2 DRUM UNIT
An organic photoconductor drum is used on this model.
To prevent stress on the drum, a drum unit is used to hold the drum without a
drum shaft.
The drum unit consists of an OPC drum [A], ID sensor board with a drum
thermistor [B], V sensor board [C], pick-off pawls [D], erase lamp unit [E], and
toner shield glass.
The pick-off pawls are always in contact with the drum surface with weak
spring pressure. They move side to side during the copy cycle. This
movement is made via a worm gear and an eccentric cam gear.
The ID sensor is used to control the toner density in the developer. The V
sensor is used for V
R
and V
L
pattern detections. The drum thermistor is used
for drum temperature control.
A green color filter [F] is stuck just above the toner shield glass on the drum
unit top plate to decrease the sensitivity of the OPC layer against red light.
The drum is driven by the main motor [G] through a timing belt [H], and a
drum drive shaft [I].
[G]
[H]
[I]
[D]
[B]
[D]
[C]
[A]
[E]
[F]
DRUM 12 February 1992
2-18