Uneven Density In The Fd And Cd - Minolta CF910 Service Manual

(12) Uneven Density in the FD and CD

Uneven Density in the FD
<Troubleshooting Procedure>
Cause Step
1
Defective IR 2
3
4
Defective 5
Developing
Unit
Defective PC 6
Drum
Defective PC 7
Drum Charge
Corona
Defective 8
Image Trans-
fer Corona
Defective 9
Developing
Unit
Defective PC 10
Drum
11
Defective PC 12
Drum Charge
Corona
1144T019AA
Check Item
Does the image problem occur
in the FD?
Is the shading sheet dirty?
Are the lens, mirror, and Origi-
nal Glass dirty?
Is the Exposure Lamp dirty or
deteriorated?
Is the Developing Unit installed
properly?
Is the PC Drum grounded
properly?
Is the Corona Wire or Meshes
dirty or deteriorated?
Is the Image Transfer Charge
being output properly?
Do the Sleeve/Magnet Roller
and Developer Supply Roller
turn properly?
Is the PC Drum grounded
properly?
Is there a sensitivity change in
the PC Drum (light fatigue)?
Are the Corona Wire and
Meshes dirty or deteriorated?
T-72
Uneven Density in the CD
1144T020AA
Result
NO Go to step 8.
YES Clean the sheet.
YES Clean the surfaces.
YES Clean or change the Expo-
sure Lamp.
NO Reinstall the unit.
NO Clean or change the PC
Drum ground plate.
YES Clean or change the
Corona Wire or Meshes.
("AIDC Mode/AIDC Offset"
and "Gradation Adjust")
NO Referring to
DIS/REASSEMBLY,
ADJUSTMENT, readjust
the charge output.
NO Check the wiring between
PWB-I and M19 and, if it is
intact, change M19.
NO Clean or change the PC
Drum ground plate.
YES After leaving the PC Drum
untouched for a while, try
making another copy. If the
same problem recurs,
replace the PC Drum.
YES Clean or change the
Corona Wire and Meshes.
Action