Brother HL 1240 - B/W Laser Printer Service Manual page 305

Image defect examples
94 mm
(3.7 in.)
94 mm
(3.7 in.)
White Spots
Printed pages have white spots in
black text and graphics at intervals
of 94 mm (3.7 in.).
94 mm
(3.7 in.)
94 mm
(3.7 in.)
Printed pages have black spots at
intervals of 94 mm (3.7 in.).
Recommendation
!
Caution
Do not try to clean the surface of the photosensitive drum with
anything sharp such as ball-point pen etc.
The drum unit may be damaged.
"How to replace the Drum unit" in Chapter 3.
4-21
CHAPTER 4 TROUBLESHOOTING
Install a new drum unit. See