Fixing device using an adjustable heater to reduce contamination on media

摘要

A fixing device includes a fusing roller, a backing roller and an adjustable heater for selectively heating the fusing roller and the backing roller. The adjustable heater includes a heating element and a reflector. The reflector can be positioned to direct heat from the heating element upon the fusing roller or the backing roller. The reflector is coupled to the shaft of a solenoid. Positioning of the reflector is controlled by alternately energizing or de-energizing the solenoid. During the time period between the passing of successive units of the media through the fixing device, the reflector is positioned to heat the backing roller. Heating the backing roller melts toner accumulated on its surface. When the next unit of the media passes between the fusing roller and the backing roller, toner accumulated on the surface of the backing roller is moved onto to the media. By heating the backing roller between the passage of successive units of the media, the quantity of toner that accumulates on the surface backing roller remains small so that the severity of print defects is reduced.