Inspect the toner cartridge to ensure that it is properly seated, that the paper path around it is free of debris, and that none of toner residue has spilled onto the printer.

Remove the toner cartridge and inspect the surface of the drum. It should be free of scratches and should rotate evenly.

If possible, run a test print from a known good file to assess the quality of the current print job.

Clean all accessible areas of the printer with a soft, dry cloth. Be sure to also clean the roller, which may be grimy and clogged with toner.

Ensure that all the printer settings are correct, including paper type, resolution, toner density, and page size.