Troubleshooting 
115
5
 
White Spots on black text 
and graphics at 94 mm 
(3.71 in.) intervals
 
Black Spots at 94 mm 
(3.71 in.) intervals
 If the problem is not solved after printing a few pages, the drum unit may have 
foreign material, such as glue from a label, stuck on the drum. Clean the drum 
unit. (See Cleaning the drum unit on page 87)
 The drum unit may be damaged. Put in a new drum unit. See Replacing the drum 
unit on page 79.
 
Black toner marks across the 
page
 The drum unit may be damaged. Put in a new drum unit. See Replacing the drum 
unit on page 79.
 The toner cartridge may be damaged. Put in a new toner cartridge. See 
Replacing the toner cartridge on page 71.
 Make sure that you use paper that meets our specifications. See Acceptable 
paper and other print media on page 3.
 If you use label sheets for laser printers, the glue from the sheets may sometimes 
stick to the OPC drum surface. Clean the drum unit. See Cleaning the drum unit 
on page 87.
 Do not use paper that has clips or staples because they will scratch the surface 
of the drum.
 If the unpacked drum unit is in direct sunlight or room light, the unit may be 
damaged.
 
Black lines down the page
Printed pages have toner stains 
down the page.
 Clean the primary corona wire inside the drum unit by sliding the green tab. See 
Cleaning the corona wire on page 85.
 Make sure the green tab of the primary corona wire is at the home position (a).
 The drum unit may be damaged. Put in a new drum unit. See Replacing the drum 
unit on page 79.
 The toner cartridge may be damaged. Put in a new toner cartridge. See 
Replacing the toner cartridge on page 71.
 The fuser unit may be contaminated. Call your dealer or Brother Customer 
Service.
Examples of poor print 
quality
Recommendation
94 mm
(3.71 in.)
94 mm
(3.71 in.)
94 mm
(3.71 in.)
94 mm
(3.71 in.)
ABCDEFGH
abcdefghijk
ABCD
abcde
01234
ABCDEFGH
abcdefghijk
ABCD
abcde
01234