Oil roller

It is placed near toner fixating set (specificaly near the heating roller). It can cause toner remainders gathering, which precipitate on the heating roller surface. The heating roller surface should be clean (in some types of printers are applied felt scrapers removing contaminations from the surface). Oil roller should be replaced on a specific period of printed copies (the most often we exchange it during copier service). Not replacing may cause that printouts are dirty.
Used in laser printers.