Samsung MultiXpress M537x series Service Manual page 330

4. Troubleshooting
1) Vertical Black Line and Band
Description : Straight thin black vertical line occurs in the printed image.
Probable Cause
The paper is not the proper type.
The paper path is contaminated by toner residue, debris etc.
The imaging unit is defective.
The transfer roller is contaminated or worn out.
The pressure roller or heat roller in fuser unit defective.
4-194
Solution
Replace the paper.
Clean the paper path.
Replace the imaging unit.
Replace the transfer roller.
1) Turn the machine off.
2) Remove and replace the fuser unit.
3) Turn the machine on.
WARNING
Do not touch the fuser unit while it is hot.
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