Brother MFC-8440 User Manual page 371

Examples of poor print
quality
94 mm
(3.7 in.)
94 mm
(3.7 in.)
White Spots on black text
and graphics at 94 mm
(3.7 in.) intervals
94 mm
(3.7 in.)
94 mm
(3.7 in.)
Black Spots at 94 mm
(3.7 in.) intervals
22 - 19 TROUBLESHOOTING AND ROUTINE MAINTENANCE
Recommendation
If the problem is not solved after printing a few pages, the drum unit may
have glue from label stock on the OPC drum surface.
Clean the drum unit as follows:
1 Position the print sample in front of the drum unit, and find the exact
position of the poor print.
2 Turn the drum unit gear by hand while looking at the surface of the
OPC drum.
Do not touch the photosensitive drum with your fingers.
3 When you have located the mark on the drum that matches the print
sample, wipe the surface of the OPC drum with a cotton swab until
the dust or paper powder on the surface comes off.
Do not try to clean the surface of the photosensitive drum with a
sharp object, such as a ball-point pen, and so on.
The drum unit may be damaged. Put in a new drum unit. (See Replacing
the drum unit on page 22-34.)
Photosensitive drum