Re-Charge Bias Control; Operation - Canon GP160F Service Manual

CHAPTER 6 IMAGE FORMATION SYSTEM
VI. RE-CHARGE BIAS CONTROL
A.

Operation

The unit re-charges once again before fixing, in order to increase the transfer toner
adhesiveness, which has been weakened by the separation static charge.
The re-charge bias is controlled by the DC controller PCB's CPU (IC301).
When a re-charge bias ON signal (RECON) is output from the CPU with the pre-
scribed timing, the drive circuit transformer T407 comes into operation and DC positive
bias is applied to the re-charge eliminator.
Also, when output voltage from the transformer T406 is returned to the bias control
circuit, constant voltage control occurs in order to output a fixed voltage.
Furthermore, the re-charge eliminator power supply bias is switched depending on
the print resolution (1200dpi equivalent and 600dpi equivalent).
The bias drive circuit, by means of the bias switching signal (1200DPI) from the
CPU, judges the print resolution and the switches output voltage.
Re-charge eliminator
[1] RECON: Re-charge eliminator
bias ON signal
[2] 1200DPI: Bias switching signal
6-8
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Drive circuit
JH405
(transformer
T407)
Figure 6-601
COPYRIGHT © 1999 CANON INC.
+24V
Bias control
circuit
Bias
switching
circuit
CANON GP160 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
DC controller PCB
[1] RECON
CPU
(IC301)
[2] 1200DPI