Brother HL-3075CW - Manual (Page 142)

Routine Maintenance
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5
d Put the print sample in front of the drum unit, and find the exact position of the poor print.
e Turn the drum unit gear by hand while looking at the surface of the OPC drum (1).
f When you have found the mark on the drum that matches the print sample, wipe the surface of the OPC
drum with a dry cotton swab until the dust or glue on the surface comes off.
IMPORTANT
DO NOT clean the surface of the photosensitive drum with a sharp object.
1