Canon CLC 1120 Service Handbook page 15

D. Image Adjustment Basic Procedure
Conditions
· copy density at '5'
· text/photo mode
Select OPTION>BODY>PASCAL=0
in service mode.
Check the height of
each charging wire.
Clean the charging wires.*
*If the primary charging
wire is soiled, replace it.
Make sample copies using TEST in
service mode for the following:
0. normal image using Test Sheet
1. PGTEST=4 using M mono color
2. PGTEST=4 using C mono color
3. PGTEST=4 using Y mono color
4. PGTEST=4 using Bk mono color
5. PGTEST=10
6. PGTEST=5 DENS 48
7. PGTEST=14 photo mode
(TXPH:1)
Adjusting the Left/Right Density Slope
Make a copy of
the Test Sheet. NO
Is the density different
between front
and rear?
YES
Is the
density different
NO
between front and rear on
the sample copy made
at PGTYPE=
10 or 5?
YES
Check to find out if the copyboard
glass is riding over something.
Is the difference
NO
in density different from
one color to another?
Clean the scanning lamp, reflecting
plate, mirror, standard white plate,
and copyboard glass.
YES
Check the coating of toner on the
developing cylinder. Check the
Execute ADJUST>CCD>CCD-ADJ
developing assembly butting roll
in service mode.
and the photosensitive drum butting
block. Clean them if soiled with toner.
Is the difference in
YES
Is the difference in
density gone?
NO
Check the original scanning lamp.
Is the density higher NO
(darker) at the rear?
YES
Turn the adjusting screw Turn the adjusting screw
at the front of the primary at the front of the primary
charging assembly charging assembly
counterclockwise. clockwise.
Execute test printing at
PGTYPE=10 or 5.
1. Check the transfer charging system.
NO 2. Clean the dust-proofing glass.
Is the difference in
3. Clean and check the developing
density gone?
assembly butting roll.
YES
Correcting Difference in Density
Is the darkest
area of the test print
made for a 16-gradation
check too light?
YES
Does the density
become lower (lighter)
gradually in continuous
copying mode?
NO
Is the density low (light)
in all colors?
YES
Execute FUNCTION>DPC>DPC
in service mode.
YES
density gone?
Is the value of
NO
DISPLAY>DPOT>V00-500,
V00-700 normal?
YES
Open the hopper, and insert the
door switch actuator. Check the
temperature and humidity using
DISPLAY>ANALOG>TEMP,
HUM in service mode.
Are the
temperature and humidity
readings normal?
NO
Check the environment sensor.
NO
To [A] of next page.
Check the high-voltage output of
YES
the internal/external static eliminator.
NO
Is the value
YES
of ADJUST>DENS identical
To [B] of next page.
with the value on
the label?
NO
Enter the data once again, and
make 50 copies.
NO
Check the laser shutter and the
laser system.
Reference (normal values)
V00-500: 430 to 570
V00-700: 600 to 800
1. Check the insulating sheet of the
transfer blade for scratches and
peeling.
YES
2. Check the shaft of the transfer
drum for play.
3. Check the cable inside the transfer
drum.
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