Making Checks On The Printer Unit - Canon Image Reader-A1 iR5000i Service Manual

CHAPTER 2 IMAGE ADJUSTMENT BASIC PROCEDURE

2. Making Checks on the Printer Unit (1/2)

<Checking Images>
Checking Halftone Images
Are there vertical NO
lines in the image?
YES
Clean the following; also check
for foreign matter:
1. Dust-proofing glass
2. Charging assemblies
Are there vertical NO
lines in the image?
YES
1. If there still is a difference in density after giving the adjusting screw 2 turns (each turn
causing a change of about 0.7 mm), check the scanning lamp and the scanner for soiling.
2. When making a clockwise turn, be sure that the intervals between wire grid runs are not
larger than 9 mm.
When making a counterclockwise turn, be sure that the intervals between wire grid runs
are not smaller than 7.5 mm.
3. The machine will not execute potential control even when the main power switch is
turned off and then on if the temperature of the fixing assembly is 150˚C or higher.
Moving the wire from the photosensitive drum causes the image to be lighter, while
moving it closer causes the images to be darker.
Memo
2-2 T
<Checking the Density Slope>
Generate a halftone image.
Is there a
NO
difference in density between
front and rear?
YES
NO
Is the rear lighter?
YES
Turn the adjusting screw Turn the adjusting screw
found at the front of the found at the rear of the
primary charging assembly primary charging assembly
clockwise. (2 full turns max.) clockwise. (2 full turns max.)
Make the selections in service mode, and turn off
Execute forced
and then on the main power switch:
potential control.
COPIER>FUNCTION>DPC>DPC.
Generate one print of a halftone image.
<Checking fro Fogging>
Generate a blank print.
NO
A
Is it foggy?
YES
Check the following readings in service mode:
COPIER>DISPLAY>DPOT>VDM (for copier image)
COPIER>DISPLAY>DPOT>VDM-P (for printer image)
Check the primary charging
NO
Are the readings ± 6 V
system and the potential control
of the target value?
system; if normal, replace the
(*1)
photosensitive drum.
YES
Check the following readings in service mode:
COPIER>DISPLAY>DPOT>VL1M (for copier image)
COPIER>DISPLAY>DPOT>VL1M-P (for printer image)
Check the following, and replace them if
necessary:
NO
Are the readings ± 6 V
1. Laser (for output)
of the target value?
2. Potential control system
(*2)
3. Photosensitive drum
YES
Check the following readings in service mode:
COPIER>DISPLAY>DPOT>VL2M (for copier image)
COPIER>DISPLAY>DPOT>VL2M-P (for printer image)
Check the following, and replace them if
NO necessary.
Are the readings 70 ± 15 V? 1. Laser (for output)
2. Potential control system
3. Photosensitive drum
YES
Adjust the offset value of the VL target potential.
Adjusting the Offset of the VL Target Potential
(DE-OFFSET/DE-OFFSET-P)
Vary the value using the following as a guide:
COPIER>ADJUST>V-CONT>DE-OFST (for copier image)
COPIER>ADJUST>V-CONT>DE-OFST-P (for printer image)
-50 -40 -30 -20 -10
COPYRIGHT © 2001 CANON INC.
REF.
*1:VD target value
COPIER >DISPLAY >DPOT >VDT (for copier image)
COPIER >DISPLAY >DPOT >VDT-P (for printer image)
*2:VL1 target value
COPIER >DISPLAY >DPOT >VD1T (for copier image)
COPIER >DISPLAY >DPOT >VD1T-P (for printer image)
Lighter image Darker image
Default
0 +10 +20 +30 +40 +50
2000 2000 2000 2000 CANON iR5000i/iR6000i REV.0 JUNE 2001