Patent ID: 8175482

Claim:
An apparatus for a printer comprising: a fuser assembly comprising a heat transfer member including a belt and a heater to heat said belt, a backup member adapted to engage said belt so as to define a fusing nip with said belt, and a temperature sensor for sensing a temperature of a portion of said backup member; and a controller coupled to said temperature sensor and based on signals generated by said temperature sensor determining whether a substrate has been contacted by a portion of said backup member portion and, upon a positive determination, determining whether said substrate is a full width substrate or is narrower than a full width substrate; wherein said controller performs the determining by sampling said temperature sensor during each fusing cycle at a first point in time after a leading edge of a substrate passes through said fusing nip and a first section on the backup member contacted by a portion of the substrate spaced from the leading edge moves adjacent to where said temperature sensor is located, and sampling said temperature sensor during each fusing cycle at a second point in time after a trailing edge of the substrate passes through said fusing nip and a second section on the backup member contacted by a portion of the substrate spaced from the trailing edge moves adjacent to where said temperature sensor is located.