Abstract: The quality of toner fusing in an electrophotographic or xerographic copier or printer is improved by modifying the reference voltage employed, in conjunction with the fuser hot roll temperature sensing, with a factor correlated to the temperature sensed in the environment of the fuser assembly. In a typical embodiment, the environment temperature is used to develop the reference voltage applied for comparison with the signal from a direct hot roll temperature thermistor. Thus, the temperature set point toward which the hot roll is driven varies as a function of the environment temperature for the fuser assembly.

Abstract: Fusing of a toned sheet of copy paper is accomplished by a fusing nip formed by a resilient hot roll and a rigid backup roll. The sheet is introduced to the fusing nip in a unique manner such that the sheet's initial contact to the hot roll fuser is substantially only a point on the sheet's leading edge. This is accomplished by orientation means operable to bow the sheet's leading edge, and/or to produce skew between the fusing nip and the sheet's leading edge.

Abstract: The temperature of a hot roll xerographic fuser is controlled by a control system which compares a command set point temperature to the fuser's actual temperature and energizes a fuser heater accordingly. A cold start of the fuser is distinguished from a warm start, and the command set point temperature is magnitude-programmed accordingly.

Abstract: An apparatus which provides for a constant center distance between all drive components in a hot roll fusing assembly during fusing nip opening/closing. This apparatus includes a roll closure device which utilizes a high mechanical advantage toggle mechanism in conjunction with a cam drive. The toggle mechanism is comprised of a pivot arm pinned to the fuser frame and a force-cell attached to the pivot arm and the shaft through the backup roll. The backup roll is constrained to rotate about the cam shaft. When the cam rotates, it rotates the pivot arm, which in turn drives the backup roll either towards or away from the hot roll while maintaining a constant center distance between the backup roll center line and a center line through the cam shaft. The drive means for the backup roll includes a first gear drivingly coupled thereto which rotates on the same axis and which meshes with a second gear rotating on the same shaft as the cam.