Canon imagePRESS C800 Series, Troubleshooting Manual

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Chapter 1
1-137
- Gradation
If there is no 16-step density gradation, it may be caused by fault of drum unit or laser scanning system.
- Foggy image
If there is foggy image only at the white area as shown in the figure below, it may be caused by fault of drum unit or laser scanning system.
- Vertical white/black line
If white or black lines occur with a particular color, the possible cause is an error in the Drum Unit of the color, an error in the Developing Assembly, or soiling on
the laser light path.
If white or black lines occur at the same position with all the colors, the possible cause is deterioration of the Intermediate Transfer Unit or Fixing Assembly.
- Density unevenness at the rear/front
If there is density unevenness at the rear/front, it may be caused by fault of drum unit, laser scanning system or transfer unit.
c-2) Full Area Half Tone (TYPE > 5)
[Reference]
- Output by every developing color is available by specifying the developing color service mode > COPIER > Test > PG > COLOR-Y/M/C/K in the following
service mode > COPIER > Test > PG.
- In the case of changing density of the test print, execute followings in service mode for density setting: service mode > COPIER > Test > PG > DENS-Y/M/C/K.
COLOR-M > 1, COLOR-Y/C/K > 0
- Transfer failure
If there is transfer failure, it may be caused by fault of transfer (intermediate transfer/secondary transfer) unit.
- Horizontal unevenness
If there is horizontal unevenness, it may be caused by fault of photosensitive drum drive unit, drum ITB motor, or drum unit.
- Vertical unevenness
If there is vertical unevenness, it may be caused by soiled LED lens, fault of drum unit, or deterioration of intermediate transfer belt.
c-3) Grid (TYPE > 6)