Fixing device and image forming apparatus including the same

摘要

A peripheral surface of a pressing roller in a fixing device has a pair of drive transmission surface portions and a paper passing surface portion. The drive transmission surface portions are respectively formed at both end portions of the pressing roller in an axial direction to transmit rotational driving force of the pressing roller to the fixing belt. The paper passing surface portion is positioned between the pair of drive transmission surface portions and has a dynamic friction coefficient lower than that of the drive transmission surface portion. It is determined whether a slip of the fixing belt occurs based on a difference between temperatures detected by a first temperature sensor that detects the temperature of the drive transmission surface portion and a second temperature sensor that detects the temperature of the paper passing surface portion. Thereby, even a slight slip of the fixing belt 42 is reliably detected.

主权项

1. A fixing device, which comprises a heating means, a fixing belt heated by the heating means, an abutting member abutting an inner peripheral surface of the fixing belt, and a pressing roller brought into press-contact with the abutting member while interposing the fixing belt between the pressing roller and the abutting member and rotationally driven in the abutting state to allow the fixing belt to be rotationally driven, and allows a paper to pass through between the fixing belt and the pressing roller so as to fix a toner image to the paper, wherein
a peripheral surface of the pressing roller has a pair of drive transmission surface portions respectively formed at both end portions of the pressing roller in an axial direction to transmit rotational driving force of the pressing roller to the fixing belt, and a paper passing surface portion positioned between the pair of drive transmission surface portions and having a lower dynamic friction coefficient for the fixing belt as compared with the pair of drive transmission surface portions, and the fixing device further comprises: a first temperature sensor arranged to face the drive transmission surface portion and detecting a temperature of the drive transmission surface portion; a second temperature sensor arranged to face the paper passing surface portion and detecting a temperature of the paper passing surface portion; and a slip determination unit that determines whether a slip of the fixing belt occurs with respect to the pressing roller based on a temperature difference between the temperatures detected by the first and second temperature sensors.