Canon GP405 Service Manual page 133

3. Controlling the Primary Charging Roller (constant voltage/current)
The DC and AC bias outputs applied to the primary charging roller are controlled by the DC
bias control signal and the AC bias control signal from the PW-CPU as follows:
The output voltage of the DC bias is returned to the PW-CPU.
The DC control signal is varied in response to the return voltage.
The DC bias assumes a constant voltage (constant voltage control).
The current for the AC bias output is taken into the drive control circuit.
The AC bias current is compared against the reference value, and the AC control signal is
varied as necessary to drive the transformer.
The AC bias will assume a constant current (constant current control).
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 6 IMAGE FORMATION SYSTEM
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