Turning On And Off The Grid Bias - Canon NP6330 Service Manual

CHAPTER 4 IMAGE FORMATION SYSTEM

4. Turning On and Off the Grid Bias

A voltage is applied to the grid wire while the primary corona current is being
generated to ensure even placement of charges on the drum.
The grid bias is controlled by the grid potential control command (GRCONT)
generated by the DC controller: a grid bias of about -800 V is applied when the DC
controller generates the GRCONT command (analog, about 5 V).
As shown in Figure 4-106, the machine keeps the grid bias at 0 V between sheets
of copy paper (A), and exerts control so that charges will not be placed on the drum by
sending primary charging corona current through the grid wire (GND).
Primary corona wire
Grid
A
Photosensitive
drum
4-8
COPYRIGHT © 1997 CANON INC.
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A
Non-charge
Charge
Figure 4-106
CANON NP6330 REV.0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
To HVT
COPY PAPER
PAPER FEED DIRECTION