In a fixing device, a first fixing member and a second fixing member are configured to form a nip in combination, and an arm biased by a first spring with a first biasing force provides a nip pressure. A cam rotatably arranged to cause the arm to move against the first biasing force has a first cam surface used to change the nip pressure from a first pressure to a second pressure smaller than the first pressure, and a second cam surface of which an angle of action is greater than that of the first cam surface to change the nip pressure from the second pressure to a third pressure smaller than the second pressure. A maximum pressure angle at the second cam surface is smaller than a maximum pressure angle at the first cam surface.

A fuser includes: a heater; a rotation body which is heated by the heater; an endless belt; an elastic pad which is in contact with an inner circumferential surface of the endless belt to form a nip portion with the endless belt intervening between the elastic pad and the rotation body; and a wall surrounded by the endless belt and disposed upstream of the elastic pad in a moving direction of the endless belt at the nip portion. The wall has a facing surface facing the elastic pad in the moving direction. The facing surface includes: contact portions positioned at both ends in a width direction of the endless belt and in contact with the elastic pad; and a center portion positioned between the contact portions in the width direction, at an upstream side of the contact portions in the moving direction.

In a rotating device, a pair of cuts are formed in an end portion of a metal-made cylindrical body to which a pressure is applied, at positions that face in a diameter direction. A support portion of a synthetic-resin-made bush rotatably supports the cylindrical body. In a state where a center of the cylindrical body matches a rotation center line of the bush, and a first diameter direction connecting respective centers in a circumferential direction of the cuts matches a second diameter direction connecting centers in the circumferential direction of a pair of engaging portions, each interval in the circumferential direction between the engaging portions and edge portions of the cuts is equal to or larger than an interval in a direction perpendicular to the rotation center line between an outer circumferential surface of the support portion and an inner circumferential surface of the end portion.

A fuser includes a rotatable member, a belt, a pressure member, and a sliding member. The pressure member sandwiches the belt together with the rotatable member to form a nip portion. The sliding member is sandwiched between an inner peripheral surface of the belt and the pressure member. The sliding member includes a front surface, which faces the inner peripheral surface of the belt. The front surface includes a plurality of first dimples and a plurality of second dimples. The first dimples are arranged in a zone corresponding to a first part of the nip portion. The second dimples are arranged in a zone corresponding to a second part of the nip portion, to which a pressure smaller than a pressure appled in the first part is applied. Each of the first dimples is of a shape that can release lubricant more easily than each of the second dimples.

A fuser includes a rotatable member, a belt, a pressure member, and a sliding member. The pressure member sandwiches the belt together with the rotatable member to form a nip portion. The sliding member is sandwiched between an inner peripheral surface of the belt and the pressure member. The sliding member includes a front surface, which faces the inner peripheral surface of the belt. The front surface includes a plurality of first dimples and a plurality of second dimples. The first dimples are arranged in a zone corresponding to a first part of the nip portion. The second dimples are arranged in a zone corresponding to a second part of the nip portion, to which a pressure smaller than a pressure applied in the first part is applied. Each of the first dimples is of a shape that can release lubricant more easily than each of the second dimples.

A fixing device includes a rotator, an endless belt, and a nip formation pad. The endless belt contacts the rotator and rotates in a direction of rotation. The nip formation pad contacts an inner circumferential surface of the endless belt to form a fixing nip between the endless belt and the rotator that presses the endless belt against the nip formation pad. The nip formation pad includes a slide layer, a base layer, and a lubricant holding layer. The slide layer contacts the endless belt. The base layer is disposed away from the endless belt. The lubricant holding layer is interposed between the slide layer and the base layer to hold a lubricant inside the lubricant holding layer and supply the lubricant to the slide layer. The slide layer has a porous structure including a plurality of through holes in a thickness direction of the slide layer.

A fixing device includes an endless belt, a pressure rotator that contacts the endless belt, a nip formation pad in the endless belt to form a fixing nip between the endless belt and the pressure rotator, a heater in the endless belt to heat the endless belt, a stay to support the nip formation pad, a contact-separation mechanism that presses the nip formation pad against the pressure rotator in a releasable manner, a holder movable between a nip formation position and a release position to support the stay, and an adjustment mechanism. The holder is provided with a slot to support the heater, and the adjustment mechanism makes a distance between the heater and the nip formation pad when the holder is at the nip formation position larger than a distance between the heater and the nip formation pad when the holder is at the release position.

An image heating apparatus includes a first rotatable member, a second rotatable member cooperative with the first rotatable member to form a heating nip, a first supporting plate supporting the second rotatable member, a second supporting plate rotatably supporting the second rotatable member, a heater unit including the second rotatable member, a heater configured to heat the second rotatable member, a connector mounted to the heater by movement relative to the heater in a first direction, a stopper portion configured to stop the relative movement of the connector relative to the heater in the first direction, and a blocking portion fixed on the first supporting plate. The blocking portion permits mounting of the heater unit with the connector being in the first position relative to the heater. The blocking portion prevents mounting of the heater unit with the connector being in the second position.

A fuser includes: a heater; a rotation body which is heated by the heater; an endless belt; an elastic pad which is in contact with an inner circumferential surface of the endless belt to form a nip portion with the endless belt intervening between the elastic pad and the rotation body; and a wall surrounded by the endless belt and disposed upstream of the elastic pad in a moving direction of the endless belt at the nip portion. The wall has a facing surface facing the elastic pad in the moving direction. The facing surface includes: contact portions positioned at both ends in a width direction of the endless belt and in contact with the elastic pad; and a center portion positioned between the contact portions in the width direction, at an upstream side of the contact portions in the moving direction.

An image heating apparatus includes an endless belt and a rotatable member configured to form a nip for heating a toner image on a recording material therebetween, a substantially stationary pad member and a movable pad member provided along a feeding direction of the recording material and configured to press the endless belt toward the rotatable member from an inside of the endless belt, a moving mechanism configured to move the movable pad member between a first position at which the movable pad member presses the endless belt toward the rotatable member and a second position at which the movable pad member does not press the endless belt toward the rotatable member, and a sheet-like member configured to cover such a surface of the stationary pad member as is opposite to the rotatable member and such a surface of the movable pad member as is opposite to the rotatable member.