Troubleshooting Image Faults - Canon GP405 Service Manual

C. Troubleshooting Image Faults
1 The copy is too light (halftone area only).
Cause
AE adjustment
Developing
assembly
Developing
assembly
Scanner
Photosensitive
drum
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Step Check
1 Perform the Image Adjustment
Basic Procedure. Is the problem
corrected?
Be sure that the pattern print is
correctly placed when executing
FUNCTION>DENS>PD-ME, DZ-
ME.
2 Make a copy in AE mode. Is the
text too light?
3 Are the rolls of the developing
assembly in firm contact with the
drum?
4 Is the surface of the developing
cylinder coated with an even layer
of toner?
5 Clean the mirror, lens, and dust-
proofing glass. Is the problem
6
corrected?
CHAPTER 14 TROUBLESHOOTING
Yes/No
YES End.
YES Execute AE adjustment.
Decrease the setting of
COPIER>ADJUST>AE>AE-
TBL.
NO Check the developing
assembly locking lever,
and check the surface of
the developing assembly
rolls for foreign mater
(e.g., toner).
NO Check the developing
assembly.
YES End.
NO Replace the drum unit.
Action
14-37