Smudges, spots and marks that repeat down the page of a Brother MFC-L5915DW are clues to which part of the print path is dirty, and the spacing of the repeating mark tells you which. Brother's user guide has a table of repeat distances for each part: a mark that recurs at the same distance down the page matches the circumference of one particular roller, the drum or the fuser, so measuring the gap between marks with a ruler tells you which part to clean or replace.
The checks in more detail
A drum or fuser that is dirty or damaged leaves a mark every turn. For random spots, first wipe the inside. Switch off and unplug, wait for the fuser to cool, open the covers and remove the toner and drum unit, and wipe the paper path and the glass of the laser window gently with a dry lint-free cloth. Do not touch the green drum surface with fingers. Shake out loose toner from the unit over a bin.
Check for paper scraps or a piece of label in the path, and check the paper itself: damp, curled or coated paper smudges, as does labels or envelopes not meant for lasers. Use the right paper type in the settings and in the tray, for the fuser's temperature depends on it. Smudges on the back of the page come from toner on the transfer roller or a dirty fuser, and a few blank pages printed at once may clear them.
Brother's machine has a drum cleaning routine in its menu on some models, run from Settings, Machine Info, if offered. If spots appear only on duplex pages, the duplex path may hold toner. A drum near end of life or a damaged toner cartridge leaves spots, so try a new cartridge. Genuine or good-quality toner leaks less. If the marks continue after cleaning and new consumables, ask Brother to check the fuser, giving the serial number and a sample page. Keep a sample for the technician, showing the repeat distance.
Differential
Likely causes of “Brother MFC-L5915DW leaves smudges, spots or repeated marks”, and how to tell them apart
- 1
A dirty or damaged drum
What separates it Marks repeat at a fixed spacing down the page
How to confirm Replace the drum unit
- 2
Loose toner or paper scraps in the path
What separates it Random spots
How to confirm Wipe the path and remove debris
- 3
Damp or wrong paper
What separates it Smudges that rub off
How to confirm Use dry paper and the right paper type
- 4
Toner on the transfer roller or fuser
What separates it Smudges on the back
How to confirm Print blank pages and clean
- 5
A leaking cartridge
What separates it Spots and dust
How to confirm Replace the toner
Before you touch a setting
Record this first — changing settings destroys the evidence
- The spacing of repeating marks
- Whether they are on the back
- The paper type
- Whether duplex pages differ
Try in this order
0 of 6 completedMeasure the repeat spacing
ReversibleDown the page.
Wipe the path
ReversibleWith a dry lint-free cloth.
Check the paper
ReversibleAnd its type setting.
Print a few blank pages
ReversibleTo clear the rollers.
Replace toner or drum
ReversibleIf marks persist.
Contact Brother
ReversibleWith a sample.
Model-specific
What is true of this model and not of its siblings
- Repeat spacing
- A clue to the part at fault.
- Fuser
- Allow it to cool before opening.
Stop boundary
When this stops being a self-service repair
- !If marks continue after cleaning and new consumables, contact Brother with the serial number and a sample
- !Keep a sample page
- !Avoid refilled cartridges
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Why are there spots on my pages?+
Loose toner, paper or a dirty drum.
What does the repeat spacing mean?+
It points to the roller or drum at fault.
Should I clean the green drum?+
Never touch its surface.
Can paper cause smudges?+
Yes, damp or coated paper.