Image Adjustment Basic Procedure - Canon GP605 Service Manual

<Making Pre-Checks>
Clean the following:
[1] Grid wire
[2] Primary charging wire
[3] Pre-transfer charging wire
[4] Transfer charging wire
Check the following:
[1] Wire height.
[2] Fixing roller nip
Make several copies of the
NA3 Chart.
Generate several of the
following test prints:
[1] PG4 halftone (printer)
[2] PG6 blank (reader)
[3] PG7 halftone (reader)
[4] PG8 solid black (reader)
Output Conditions
· AE OFF
· Fat 5
· Potential control ON
If the test prints have a fault,
Go to
Checking the Scanner Side
2
COPYRIGHT © 1999 CANON INC. CANON GP605/605V REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
<Making Image Initial Checks>
Does
NO
the copy have
vertical lines?
YES
Clean the following, and check for
adhesion of foreign matter:
[1] Dust-proofing glass
[2] Charging assemblies Clean the
following, and check for
adhesion of foreign matter:
Does the
NO
copy have vertical
lines?
YES
Check the following:
[1] Drum cleaning blade
[2] Separation claws
<Checking the Density Slope>
Check PG7 (halftone).
Is there NO
a difference in
density between front
and rear?
YES
Is the rear NO
lighter?
YES
Turn the adjusting screw at
Turn the adjusting screw at
the front of the primary
the rear of the primary
charging assembly
charging assembly
counterclockwise. (1.5 mm
counterclockwise. (1.5 mm
max. in one direction)
max. in one direction)
Execute potential
control.
Turn off and then on the power switch,
and generate one test print of PG7.
Caution:
[1] If the difference in density still exists after
turning the adjusting screw 1.5 mm in one
direction (a single full turn causes a change of
0.7 mm), check the charging assembly,
scanning lamp, and scanner for dirt.
[2] When turning the adjusting screw
counterclockwise, be sure that the height of the
wire is not 7.5 mm or less.
A . Image Adjustment Basic Procedure
1 Checking the Printer Side (1/2)
<Checking Solid Black>
Check PG8 (solid black).
Is
the copy
YES
free of fuzzy images
and is its density
proper?
NO
Select COPIER>DISPLAY>DPOT>VDM
in service mode.
Check the
potential control
Is the
NO
system; if normal,
reading of VDM
between 432 replace the
and 452?
photosensitive
drum.
YES
Select COPIER>DISPLAY>DPOT>VL1M
in service mode.
Check the following;
if normal, replace the
Is
appropriate part:
NO
the reading
[1] Laser output
of VL1M between 62
[2] Potential control
and 82?
system
YES
Replace the
Is the test
YES
developing
print of PG6 (blank)
assembly.
foggy?
NO
Set OPTION>BODY>CNT-W/HM
in service mode between 2 and 7.
· A higher setting increases the
density.
A
13-3