Canon iR6570 series Service Manual page 476

Chapter 13
B
13-4
<Checking the Solid Black Density>
Generate a solid black print.
Is the density
too low or too high (too
light or too dark)?
YES
Check the following readings (VD target value) in service mode:
COPIER>DISPLAY>DPOT>VDM (for copier image)
COPIER>DISPLAY>DPOT>VDM-P (for printer image)
Are the
readings ± 6 V of the
target value?
(*1)
YES
Check the following readings (VL1 target value) in service mode:
COPIER>DISPLAY>DPOT>VL1M (for copier image)
COPIER>DISPLAY>DPOT>VL1M-P (for printer image)
Are the
readings ± 6 V of the
target value?
(*2)
YES
Adjust the offset of the VD target potential.
NO
Check the primary charging
NO
system; if normal, replace the
photosensitive drum.
Check the following, and replace them if
necessary:
NO
1. Laser (for output)
2. Potential control system
3. Photosensitive drum
F-13-4
C
D