Periodic Uneven Density - Minolta CF910 Service Manual

(24) Periodic Uneven Density

<Troubleshooting Procedure>
Cause Step
Defective PH 1
Defective PC 2
Drum Rota-
tion
Defective PC 3
Drum Drive
Defective 4
Image Trans-
fer Corona
Defective
Developing
Unit
Check Item
Are the uneven pitches at
intervals of between 0.5 and
0.6mm?
Are the uneven pitches at
intervals of about 1mm?
Are the uneven pitches at
intervals of between 2mm to
3mm or 10mm?
Are the uneven pitches at
intervals of more than those
mentioned above?
T-92
1144T035AA
Result
YES Check the installation of
each PH Assy. If it is cor-
rect, replace the PH Upper
and Lower Assy.
YES A. Check the developer Ds
Rolls. Clean the Carrier
Retrieving Roller and
the edges of the PC
Drum. If they are
extremely dirty or
scratched, replace
them.
B. Replace the PC Drum
Bushings.
C. Clean or replace the
side seals.
YES A. Check the looseness of
the flywheel fixing bolt.
B. If the PC Drum Drive
Gear or Speed Reduc-
tion Gear is dirty or
damaged, clean or
replace them accord-
ingly.
YES A. Check that the amount
that the Backup Blade
sticks out is correct.
B. Check the cushion in
the Backup Paper Lift-
ing Mechanism.
C. Clean the Drum Ring.
D. Clean the Static Charge
Roller and Rolls.
E. Clean Developing Unit.
Action