Canon GP215 Service Handbook page 42

TROUBLESHOOTING IMAGE PROBLEMS
2 The copy is too light. (including solid black)
Cause Step
1
2
Transfer 3
roller unit
4
5
6
7
Copy paper
8
Transfer
guide
High-voltage
cord, High-
voltage
transformer,
DC con-
troller PCB
9
Developing
assembly
Toner 10
detecting
assembly
11
Drum unit
Image proces-
sor PCB,
Analog proces-
sor PCB
3–6
Checks
Perform the Image Adjustment
Basic Procedure. Is the prob-
lem corrected?
Turn off the power switch in the
middle of copying operation,
and open the front door. Is the
toner image on the surface of
the photosensitive drum more
or less normal?
Is the transfer roller unit proper-
ly installed?
Does leakage occur in the
transfer roller unit?
Is there dirt, cracks, or scratch-
es on the transfer charging
roller?
Is the position and condition of
the transfer charging roller
pressure spring normal?
Try fresh copy paper. Is the
image darker?
Set the feeding assembly in the
feeding position, and measure
the resistance between the
transfer guide and the mount
(metal portion) of the transfer
charging assembly rail. Is the
resistance 0 ?
Is the developing assembly
properly installed? (Check to
make sure that the developing
rolls are in firm contact with the
photosensitive drum.)
Is there toner in the developing
assembly?
Replace the drum unit. Is the
problem corrected?
Yes/No Action
YES End.
The image will become appre-
ciably light if the pattern print is
placed in reverse (left/right) ori-
entation. Be sure to place it in
correct orientation.
NO Go to step 9.
NO Install the transfer roller unit
securely.
YES Check the transfer roller unit.
YES Replace the transfer charging
roller.
NO Correct the position of the
spring, or replace the spring.
YES 1. The paper may be moist;
advise the user on the cor-
rect method of storing paper.
2. Advise the user that the use
of non-recommended paper
may not bring about the best
results.
YES Check if the transfer guide
should be in contact with a
metal portion (e.g., side plate
of the feeding assembly).
NO 1. Check the high-voltage cord
for electrical continuity.
2. Check the high-voltage
transformer DC controller
PCB.
NO Re-install the developing
assembly.
NO 1. Check the toner sensor.
2. Check the connector and
the harness for electrical
continuity.
YES End.
NO Try replacing the image
processor PCB or the analog
processor PCB.