When a sheet with a high-density image on it is delivered or when the toner is not fused well, toner may stick to the rollers and guide boards in the finisher, where it may stain the transfer surface or sheet edge.
If you notice such staining, clean the rollers and guide boards in the finisher.
Use the following procedures to clean the rollers and guide boards in the finisher:
Roller
Wipe the roller with a well-wrung-out damp cloth, and then wipe with a dry, unused, lint-free cloth until no moisture remains.
Guide Board
Wipe the guide board with a well-wrung-out damp cloth. To clean the innermost recesses, use a cloth that is as large as your palm.