In an image heating apparatus, a plurality of heat-generating members that a heater has include a first heat-generating member group and a second heat-generating member group, symmetrically laid out with a conveyance reference position of a recording material. A control portion supplies electric power via first and second common circuits to the first heat-generating member group and the second heat-generating member group. A temperature-detecting portion includes a first temperature-detecting element for detecting a temperature of one of the heat-generating members included in the first heat-generating member group, and a second temperature-detecting element for detecting the temperature of one of the heat-generating members included in the second heat-generating member group. The first temperature-detecting element is placed on one side as to the conveyance reference position in the width direction, and the second temperature-detecting element is placed on other side as to the conveyance reference position in the width direction.

A fixing belt includes, in the following order: a resin base material layer; an elastic layer; and a release layer, in which the elastic layer contains an elastic material and an aggregate in which plural fibrous carbons are entangled with each other, and a maximum diameter of the aggregate is 15% or less of a film thickness of the elastic layer.

A fixing device includes a rotatable endless belt; a holding section that is disposed inside the belt and holds a planar heat-generating element so as to bring the belt into pressure contact with a rotating body at a pressure contact portion; and a roughened portion that is provided adjacent to a downstream side in a movement direction of the belt with respect to the pressure contact portion of the holding section and subjected to a roughening treatment for holding abrasion powder on an inner surface of the belt.

A belt device includes a secured member, a belt, a pressure rotator, and lubricant. The belt has an endless shape and slides on a slide surface of the secured member. The belt has an inner portion having an elastic power of 55% or more and a sliding surface sliding on the slide surface of the secured member. The sliding surface has a surface roughness smaller than a surface roughness of the slide surface of the secured member. The pressure rotator presses the secured member via the belt to form a nip between the belt and the pressure rotator. The lubricant is interposed between the sliding surface of the belt and the slide surface of the secured member.

The fixing device includes a fixing member, a heat source, a pressure member, a nip forming member, and a heat equalizing member. The heat equalizing member covers a face of the nip forming member, the face facing the fixing member, and transfers heat in an axial direction of the fixing member. The fixing member includes at least a tubular base made of metal and a sliding layer made of heat resistant resin on an inner circumferential surface of the base. The heat equalizing member made of aluminum or an aluminum alloy includes an alumite layer on a surface facing an inner circumferential surface of the fixing member. A plurality of micropores in the alumite layer is filled with a solid lubricant having a coefficient of friction lower than that of the alumite layer. The alumite layer has a thickness smaller than that of the sliding layer of the fixing member.

An image forming apparatus is operable in a first small-sheet printing in which power is supplied to the first heat generating element and the second heat generating element and in a second small-sheet printing in which power is supplied to the first heat generating element and the third heat generating element. A first power ratio, which is a proportion of power supplied to the first heat generating element to power supplied to the second heat generating element in the first small-sheet printing, is higher than a second power ratio, which is a proportion of power supplied to the first heat generating element to power supplied to the third heat generating element in the second small-sheet printing.

In an image forming device, a first fixing member has a roller. A second fixing member has a belt to form a nip together with the first fixing member. A first motor drives the roller. A pressure modifying mechanism modifies a nip pressure at the nip to selected one of a first nip pressure and a second nip pressure smaller than the first nip pressure. A controller starts driving the first motor to drive the roller in a case where a print command is received in a state that the nip pressure is the second nip pressure. The controller modifies the nip pressure from the second nip pressure to the first nip pressure after the driving is performed and fixes the developer image on the sheet in a state that the nip pressure is the first nip pressure.

A heating device includes a cylindrical film a heater disposed inside the cylindrical film on an inner surface of the cylindrical film. The heater has a plurality of heating elements that are spaced from each other at intervals along an axial direction. A heat transfer member contacts the heater. The heat transfer member is arranged such that, in a first region of the heater that includes just a single one of the heating elements, contact between the heater and heat transfer member is greater than in a second region of the heater that includes an interval between a pair of adjacent heating elements.

A fusing device thermally fuses a toner image formed on a sheet. The fusing device includes a sliding sheet having a sliding contact surface. The inner circumferential surface of a fusing belt comes into contact with and slides on the sliding contact surface. The sliding sheet has a fabric structure containing fluororesin fibers. The fluoroplastic fibers that are flattened by thermal pressure are disposed on the sliding contact surface, Thus, the sliding sheet has heat resistance.

A heating device includes a belt, an opposed rotator, a heater, a nip formation pad inside the belt, a holder holding the nip formation pad, a stay supporting the holder. The nip formation pad or the holder includes pad positioning portions and a holder positioning portion. The pad positioning portions includes a first and second pad positioning portions at both ends of the nip formation pad or the holder with respect to a center of the heater, and a third pad positioning portion near the center. The holder positioning portion is nearer to the center than the first or the second pad positioning portion.