Setting The Grid Bias And The Developing Bias - Canon 1130 Service Manual

CHAPTER 6 IMAGE FORMATION SYSTEM

5. Setting the Grid Bias and the Developing Bias

The grid bias and the developing bias DC component are determined using Vd/VL values,
dark area potential attenuation value, and target contrast potential value.
A line is drawn for the developing bias DC (Vdc) running through points representing the sum
of Vd and Vback voltages (for removal of fogging during copying operation; the Vback voltage is
set to 110 to 130 V according to the content of moisture measured by the environment sensor).
Then, a point where the contrast potential between Vdc and VL (Figure 6-204) is identical to
the target contrast potential is found, and the target values of the grid bias and the developing bias
are obtained.
Drum surface potential/
developing bias
DC component
The measurements of the surface potential may be checked by executing
FUNCTION>DPC>DPC in service mode (DISPLAY>DPOT); use the following as a guide in the
field:
6-12
COPYRIGHT © 2002 CANON INC.
Target contrast potential
(V)
-370V
-520V
Figure 6-204
Image display
V00-500V
V00-700V
VFF-500V
VFF-700V
Table 6-203
CANON CLC1100/1130/1150/1160/1180 REV.1 JAN. 2000 PRINTED IN JAPAN (IMPRIME AU JAPON)
Vd
Vback
Vdc
Contrast potential
VL
(V)
Grid bias
Approximate guide
430 to 570
600 to 800
50 to 150
100 to 200