Lexmark T522 fuser components

The function of the fuser is to melt the toner and bake it onto the paper. The fuser is the part most likely to wear and need overhauling. In commercial-duty Lexmark printers, the fuser is a modular unit that can be removed as a complete sub-assembly. The principal parts in the fuser are a Teflon coated aluminium upper fuser roller (hot roller - usually metallic grey or green); a silicon rubber lower fuser roller (pressure roller, usually an orange colour); a halogen lamp (heating element) inside the hot roller; and a thermistor to monitor the fuser temperature. The Teflon coating on the hot roller gradually wears off or is damaged by the user (like the coating on a Teflon frying pan); the silicon rubber pressure roller becomes soft, its surface may become rippled or the roller may become out-of-round resulting in thumping noises during normal printing; the halogen bulb may fail; and the thermistor may become coated with baked-on toner or lose contact with the hot roller and cause the fuser to overheat.

Sometimes it is necessary to overhaul/replace the fuser before the recommended maintenance interval. This is usually the result of user abuse eg by re-using paper that has already been printed on one side and forgetting to remove staples, paper clips etc; or by using poor quality paper that causes excessive wear on the rollers. The components of the fuser eg the thermistor can also be damaged by excess toner from a leaking toner cartridge. Sometimes the fuser can be damaged by the printer being kept in a ready state for long periods without being used: the rubber pressure roller is kept hot by being pressed against the hot roller and may develop flat spots as a result of staying in one position for too long.

When we refurbish a printer, we always overhaul the fuser and insert new parts as required. We do this regardless of how many pages the printer has apparently produced. We always replace the hot roller; pressure roller; thermistor and bearings. We often replace the hot roller and pressure roller bushes; gears; heating lamp; detack assembly and fuser exit rollers.