White Spots; Black Spots - Brother DCP-7055 Service Manual

■ White spots

Step
Dirt on the electrodes of the drum
1 unit and the machine body
High voltage power supply PCB
2
ASSY failure
3 Main PCB failure

■ Black spots

Step
Dirt on the electrodes of the drum
1 unit and the machine body
Dirt on the heat roller
2
Scratch on the heat roller
3
(Black spots at 53.4 mm)
High voltage power supply PCB
4
ASSY failure
5 Main PCB failure
User Check
• When the white spots at 32.5 mm are intervals, replace the toner
cartridge with a new one.
• If the same problem occurs after printing a few pages, the adhesive
of the label or the like, paper powder or dirt may be attached on the
surface of the exposure drum. Wipe off the dirt on the exposure
drum. (Refer to User's guide, and perform the Drum Cleaning.)
• When the white spots at 94.2 mm are intervals, replace the drum
unit with a new one.
Cause
User Check
• When the black spots at 32.5 mm are intervals, replace the toner
cartridge with a new one.
• If the same problem occurs after printing a few pages, the adhesive
of the label or the like, paper powder or dirt may be attached on the
surface of the exposure drum. Wipe off the dirt on the exposure
drum. (Refer to User's guide, and perform the Drum Cleaning.)
• When the black spots at 94.2 mm are intervals, replace the drum
unit with a new one.
Cause
2-88
Remedy
Clean the electrodes of the drum unit and
machine body. (Refer to
12.)
Replace the high voltage power supply
PCB ASSY.
Replace the main PCB ASSY.
Remedy
Clean the electrodes of the drum unit and
machine body. (Refer to
12.)
Refer to "2-85 How to clean the heat
and clean the heat roller.
Replace the fuser unit.
Replace the high voltage power supply
PCB ASSY.
Replace the main PCB ASSY.
Fig. 2-11, Fig. 2-
Fig. 2-11, Fig. 2-
roller",
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