Fixing device and image forming apparatus with inclined regulation surface

摘要

A fixing device includes a fixing roller, a pressure roller, and a regulation member. The fixing roller includes a roller member and a fixing belt. The roller member includes a shaft which extends in one direction and an elastic layer integrally formed on the shaft. Each regulation member has an annular regulation surface which opposes a side edge of the fixing belt, and is configured to regulate movement of the fixing belt in a rotation axis direction. The regulation surface is inclined relative to a line perpendicular to the rotation axis as viewed on a cross-section parallel to the rotation axis. The regulation surface is inclined from the rotation axis side such that the closer the regulation surface is to an outside, in a radial direction, of the fixing roller, the closer the regulation surface is to a center, in a length direction, of the shaft.

主权项

1. A fixing device comprising:
a fixing roller including a roller member having a shaft which extends in one direction and an elastic layer integrally formed on the shaft and a fixing belt fitted onto the roller member, the fixing roller configured to rotate about an axis of the shaft as a rotation axis; a pressure roller configured to form a fixing nip portion between the pressure roller and the fixing roller; and a respective regulation member mounted at each end portion of the shaft, each regulation member having an annular regulation surface which opposes a side edge of the fixing belt, each regulation member configured to regulate movement of the fixing belt in a rotation axis direction, wherein the regulation surface is inclined relative to a line perpendicular to the rotation axis as viewed on a cross-section parallel to the rotation axis, the regulation surface is inclined from the rotation axis side such that the closer the regulation surface is to an outside, in a radial direction, of the fixing roller, the closer the regulation surface is to a center, in a length direction, of the shaft, the regulation surface is inclined such that, when θ1 represents an inclination angle of an inner region, in the radial direction, of the regulation surface relative to the line perpendicular to the rotation axis, and θ2 represents an inclination angle of an outer region, in the radial direction, of the regulation surface relative to the line perpendicular to the rotation axis, θ2>θ1 is satisfied, each regulation member is a disk-shaped member, each regulation member includes a hole into which the shaft is inserted, an annular flat surface opposing a side edge of the elastic layer of the roller member and being parallel to the side edge of the elastic layer, the regulation surface connecting with an outer side portion, in the radial direction, of the annular flat surface, and an outer circumferential surface connecting with an outer side portion, in the radial direction, of the regulation surface so as to be parallel to the rotation axis, and the elastic layer of the roller member includes an inclined surface whose diameter gradually decreases toward the side edge of the elastic layer, wherein a chamfered portion is provided in a boundary portion between the outer side portion, in the radial direction, of the regulation surface, and the outer circumferential surface.