Dropouts; Vertical White Lines; Horizontal White Lines; Loose Toner - Canon imageCLASS LBP6780dn Service Manual

5
Troubleshooting > Corrective Actions > Image Defects > Loose toner

■ Dropouts

F-5-10
Dropout appears in image
Cause
1) The transfer roller is dirty or deformed
2) Poor high-voltage contact with the cartridge
3) The photosensitive drum, primary charging
roller, developing roller is defective
4) Scratches or foreign substance on the fixing
film
5) The high-voltage power supply is defective

■ Vertical white lines

F-5-11
Vertical white line appears in image
Cause
1) Scratches on the circumference of the
photosensitive drum
2) The developing roller is defective
3) Foreign substance adheres to the laser beam
window of the printer or cartridge
5 Troubleshooting > Corrective Actions > Image Defects > Loose toner
Solution
Replace the transfer roller.
Clean the contact if dirty.
Replace the cartridge.
Replace the fixing unit.
Replace the high-voltage power supply unit.
T-5-10
Solution
Replace the cartridge.
Replace the cartridge.
Remove foreign substance from the laser beam
window.
Cause
4) Foreign substance adheres to the fixing inlet
guide or the guide is dirty
5) Scratches or foreign substance on the fixing
film
6) The mirror in the laser scanner unit is dirty

■ Horizontal white lines

F-5-12
Horizontal white line appears in image
Cause
1) Horizontal scratches on the photosensitive
drum
2) The fixing film is defective

■ Loose toner

F-5-13
Toner image is not fully fixed on the media
Cause
1) The pressure roller is dirty
2) The fixing film or the pressure roller is defective Replace the fixing unit.
Solution
Clean the fixing inlet guide.
Replace the fixing unit.
Replace the laser scanner unit.
T-5-11
Solution
Replace the cartridge.
Replace the fixing unit.
T-5-12
Solution
Execute a "pressure roller cleaning"
T-5-13
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