Ricoh B286, Service Manual

Page: 532 / 622

Around the Drum
B286/B289 6-24 SM
6.4.2 DRUM DRIVE
The drum motor [A] controls:
! Timing gears [B]
! Timing belt and wheel [C]
This turns the OPC drum [D].
Gear [E] (meshed with the OPC drum) turns the cleaning unit auger [F].
When paper feed starts:
! The drum motor switches on and turns the drum forward.
! While the drum turns forward, the LPH writes the ID sensor pattern on the drum, then
the drum turns forward 250 mm more.
! The ID sensor reads the pattern (Vsp) and the surface of the drum (Vsg) to find
Vsp/Vsg for toner density control.
The drum motor turns the drum in the opposite direction at the end of each job for 0.3 s.
This removes paper dust (caused when the paper roll is cut) from the cleaning blade.