A belt unit includes an endless belt including a metal layer, a nip forming member having a heater that includes a heat generating element, a metal stay that presses the nip forming member toward a rotatable member, and a temperature detecting element. A metal leaf spring urges the temperature detecting element toward the inner peripheral surface of the endless belt, and an insulating supporting member is positioned inside the stay and supports the leaf spring. A cord electrically connects with the temperature detecting element through the leaf spring, and an insulating holder portion includes an interposed portion interposed between an exposed portion of the leaf spring and the stay, so as to provide insulation therebetween, and to hold the supporting member. A creepage distance from the heat generating element to the exposed portion of the leaf spring, through the stay and the interposed portion, is 2.5 mm or more.

A fixing device includes a fixing roller, a pressure member, a heating device, a first pressing member, a second pressing member, and a pair of bearings. The pressure member is configured to nip a recording medium in cooperation with the fixing roller. The heating device is disposed opposite to the pressure member relative to the fixing roller. The first pressing member is configured to press the pressure member toward the fixing roller with a first pressing force. The second pressing member is configured to press the heating device toward the fixing roller with a second pressing force. The fixing roller includes a driven gear to be driven by a drive gear that is configured to apply a third pressing force to the driven gear. The third pressing force includes a component opposite in direction to a resultant force of the first pressing force and the second pressing force.

In this fixing device, a pressing roller includes a pressing roller driving unit, and a heating roller includes a heating roller driving unit. Control is performed such that torque of the heating roller in torque distribution between the pressing roller and the heating roller is greater when a belt load reducing device is activated than when the belt load reducing device is not activated. A fixing device and an image forming apparatus thus can be provided, in which the fixability according to the kind of recording medium is excellent, the durability of the fixing belt is high, and the separability between the fixing belt and the recording medium is excellent.

A belt unit includes an endless belt including a metal layer, a heater including a heat generating element, a nip forming member including the heater, a metal stay, a temperature detecting element, a metal leaf spring, an insulating supporting member positioned inside the stay, a cord, and an insulating holder portion including an interposed portion interposed between an exposed portion of the leaf spring and the stay so as to provide insulation therebetween and for holding the supporting member.

An image heating apparatus includes a rotatable heating member, a first motor configured to rotationally drive the rotatable heating member, a belt unit, a position detecting portion, a tilting mechanism including a second motor for tilting the belt unit, a jam detecting portion, and a controller. When the occurrence of the jam is detected by the jam detecting portion during a tilting operation of the belt unit, the controller stops drive of the first motor and drive of the second motor in response to detection of the occurrence of the jam by the jam detecting portion.

A belt deviation correction device for correcting a deviation of an endless belt wound around a plurality of rollers includes a pressing roller that is pressed from outside the endless belt wound around the plurality of rollers. The pressing roller is configured to swing in such a way as to be inclined with respect to the plurality of rollers. A deviation of the endless belt in a direction of an axis of rotation of the plurality of rollers is corrected by swinging the pressing roller.

A fixing device includes a first pressure structure, a second pressure structure, a fixing member, a first arm, a second arm, and an elastic member. The fixing member is disposed between the first and second pressure structures. The first arm is pivotable about a first shaft and includes a first pressing portion and a first connection portion. The second arm is pivotable about a second shaft and includes a second pressing portion and a second connection portion. The elastic member biases the first and second pressing portions toward each other. A first leverage ratio of a distance between the first shaft and the first connection portion to a distance between the first shaft and the first pressing portion is different from a second leverage ratio of a distance between the second shaft and the second connection portion to a distance between the second shaft and the second pressing portion.

A heating device includes an elongated heater, a first holding member configured to hold the heater, a power shut-off member configured to shut off power supply to the heater, a second holding member configured to hold the power shut-off member, a first urging member configured to press the power shut-off member against the heater, and a regulation member configured to regulate a position of the second holding member, wherein, in a longitudinal direction of the heater, one end side of the second holding member is urged by the first urging member, and another end side of the second holding member is regulated in position by the regulation member.

A fixing device includes a first pressure structure, a second pressure structure, a fixing member, a first arm, a second arm, and an elastic member. The fixing member is disposed between the first and second pressure structures. The first arm is pivotable about a first shaft and includes a first pressing portion and a first connection portion. The second arm is pivotable about a second shaft and includes a second pressing portion and a second connection portion. The elastic member biases the first and second pressing portions toward each other. A first leverage ratio of a distance between the first shaft and the first connection portion to a distance between the first shaft and the first pressing portion is different from a second leverage ratio of a distance between the second shaft and the second connection portion to a distance between the second shaft and the second pressing portion.

An image heating apparatus includes a first heater for heating a first roller, a second heater for heating a second roller, a first sensor for detecting a temperature of a region of an endless belt supported by the first roller, a second sensor for detecting a temperature of a region of the endless belt supported by the second roller, and a controller for controlling energization to the first heater and to the second heater. The controller executes a first mode in which the energization to the first heater is controlled using an output of the first sensor and the energization to the second heater is controlled using an output of the second sensor, and a second mode in which the energization to the first heater and the second heater is controlled using the output of the first sensor without using the output of the second sensor.