Patent ID: 8295753
Filing Date: 2012-10-23
Classification: G03G

Abstract:
1. A fixing device, comprising: a fixing roller which is rotatably supported; a belt holding member; a fixing belt which is endless and which is rotatably held around the fixing roller and the belt holding member; first heating means for heating the fixing belt; a pressing member which is capable of being pressed against the fixing roller via the fixing belt; first driving means for driving the fixing roller to rotate; and a disjunction mechanism for switching a relative position of the pressing member and the fixing roller from a first position to a second position, or vice versa, the first position being a position at which the pressing member and the fixing roller are pressed against each other via the fixing belt, the second position being a position at which the pressing member and the fixing belt are separated from each other; the fixing device fixing an unfixed toner image, formed on a recording material, to the recording material by causing the recording material to pass through a nip at which the fixing belt and the pressing member are pressed against each other, the fixing belt satisfying where: D (mm) represents a first inner diameter of a loop of the fixing belt held in a state where the fixing belt is looped in a shape of a circle without suspension; A (mm) represents a second inner diameter of the fixing belt, the second inner diameter being a distance between respective axial centers of a supporting member and a spindle in a state where the fixing belt is held with a tensile load of 0.383 gf/mm by (i) suspending the fixing belt from the supporting member inserted in a loop of the fixing belt, and (ii) further inserting the spindle in the loop of the fixing belt, the supporting member and the spindle having a shape of a roller with a diameter of 0.26×D (mm); ER represents an elongation rate (%) of the fixing belt and is formulated as μ represents a coefficient of kinetic friction between the fixing belt and the fixing roller, the fixing belt being driven by the fixing roller to rotate in a case where the fixing roller is driven by the first driving means to rotate in a state where the relative position is set to the second position.