Brother HL 3070CW - Manual (Page 146)

Routine Maintenance
136
5
Large spots on the printed pages
5
If your printout has colored 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 color causing the problem. The color of the spots is the color 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 color causing the problem.
1