Canon 1000 Service Manual page 149

The DC bias is turned on and off, and the voltage is controlled as follows:
Developing bias enable signal (HVDCEN)=1
The DC bias output signal HVDC (between 0V and 12 V) is sent to the voltage control circuit.
The output from the transformer is controlled to suit the voltage of HVDC and is applied to
the developing cylinder.
The DC bias output signal (HVDC) and the developing bias enable signal (HVDCEN) have four channels
(for each color), and each of the four channels is controlled independently.
The changes in the developing DC bias
according to different voltage values are as shown
in Figure 3-530.
COPYRIGHT © 2001 CANON INC. CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
3. OPERATION AND TIMING
12V
11V
0V
-200V
Developing DC bias
Figure 3-530
-750V
3-105