Patent ID: 8112015

Claim:
A belt unit comprising: an endless belt; and a plurality of rollers supporting the endless belt, wherein at least one roller of the plurality of rollers includes a flange arranged on an end portion of the roller, the flange includes a cylindrical portion that is inserted into an opening portion of the roller at the end portion of the roller, an outer circumference of the cylindrical portion makes contact with an inner circumference of the roller, an inner circumference of the flange makes contact with a rotation shaft of the roller, a first inner edge of a first surface where the flange is in contact with the rotation shaft is located on an inner side of a second outer edge of a second surface where the cylindrical portion is in contact with the roller in a longitudinal direction of the rotation shaft, and the second outer edge of the second surface where the cylindrical portion is in contact with the roller is farther from a center position of the rotation shaft in the longitudinal direction of the rotation shaft than a first outer edge of the first surface where the flange is in contact with the rotation shaft.