Controlling The Bias To The Transfer Roller - Oce 3121 Technical & Service Manual

2 Controlling the bias to the transfer roller

Outline
The copier uses direct transfer executed by means of a roller. Four charging po-
tentials are applied to the transfer roller. These have the following functions
and timing:
Composite power supply PCB
T101
J209-B4
J102-B6
Transfer Bias
This positive bias is used to transfer the image from the OPC to the copy paper.
502 TSM Océ 3121
T502
T101
Transforemer
(increase)circuit
5V
Constant
current
control
drive
Overcurrent
circuit
detection
Q605
J209-B5
J102-B7
IC101
CPU
DC controller PCB
24VU
24VU
Transformer
output
24VU
detection
24VR
CPU
J209-A4~A9
J102-A1~A7
Photosensitive
drum
Transformer
Functional description