Fixing belt unit and fixing device

Abstract

A heating efficiency 600 includes a substrate 610 and a plurality of heat generating elements 523a to 623f which are provided on both surfaces of the substrate 610 and which generate heat, and heats a fixing belt in contact with an inner peripheral surface of the fixing belt. The plurality of heat generating elements 623a to 623f are different from each other in length with respect to a widthwise direction, and at least three of the heat generating elements are provided on a front surface of the substrate 610 which is a side where the heater 600 contacts the inner peripheral surface of the fixing belt 600, and at least one of the heat generating elements is provided on a back surface. A longest heat generating element 623b, in length with respect to the widthwise direction, of the plurality of heat generating elements 623a-623f is provided on the front surface. Further, as regards the heat generating elements 523a-623c provided on the front surface, with respect to a rotational direction of the fixing belt, the longest heat generating element 623b in length with respect to the widthwise direction is disposed between the heat generating element 623a and the heat generating element 623c.

Dependencies are inferred from the claim text.