Brother HL HL-3070CW User Manual page 146

Large spots on the printed pages
If your printout has coloured spots at 94 mm (3.7 in.) intervals, follow the steps below to solve the problem.
a
Turn off the printer power switch. Fully open the top cover by lifting up on the handle (1).
b
See the print sample to identify the colour causing the problem. The colour of the spots is the colour of
the drum you should clean. For example, if the spots are cyan, you should clean the drum for cyan. Take
out the drum unit and toner cartridge assembly of the colour causing the problem.
1
Routine Maintenance
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