A heating device includes a heater, a rotator, and a pressure rotator. The heater includes resistive heat generators forming a heat generation area and has a separation area formed by the resistive heat generators. The pressure rotator includes a first region and a second region. The first region faces the heater in a range of 20 mm from a center position of the heat generation area toward an end thereof in the arrangement direction. The second region faces the heater in at least a part of a range of 30 mm from a center position of the separation area toward the center position of the heat generation area. An outer diameter of the pressure rotator increases from the center toward the end. The outer diameter of the second region increases at an increasing rate larger than an increasing rate of the outer diameter of the first region.

A contact-separation device brings a contact-separation member into contact with a contacted member separably and includes a biasing member that generates a biasing force. A presser presses the contact-separation member against the contacted member in a pressing direction with the biasing force from the biasing member. A cam presses the presser in an opposite direction being opposite to the pressing direction. The cam is rotatable and has a cam face. A cam follower has a cam contact face that contacts the cam face of the cam. The cam contact face is curved to project toward the cam. The cam contact face has a curvature that is smaller than a greatest curvature of the cam face of the cam and is greater than a smallest curvature of the cam face of the cam.

A fixing member is supported so as to be displaceable in a crossing direction that crosses a sheet conveying direction. A pressure member rotationally drives the fixing member by being rotationally driven. A motor rotationally drives the pressure member. A biasing mechanism elastically biases the fixing member toward the pressure member. A sheet detection portion detects a sheet at a first position and a second position. The first position is a position between a mechanism that feeds the sheet to a fixing position and the fixing position in the conveyance path. The second position is a position between the fixing position and a mechanism that takes over conveyance of the sheet from the fixing device. A control device times a time required for detection results from the sheet detection portion to show a predetermined change, and controls a rotational speed of the motor according to the timed time.

An image forming apparatus includes an image forming portion, a fixing portion configured to heat and press the sheet conveyed from the image forming portion while nipping and conveying the sheet by a first nip portion to fix toner image to the sheet, a folding portion configured to fold the sheet, and a bonding portion configured to heat and press the sheet folded by the folding portion while nipping and conveying the sheet by a second nip portion to bond the sheet by powder adhesive. A peak value of pressure that the second rotary member pair applies to the sheet in the second nip portion is greater than a peak value of pressure that the first rotary member pair applies to the sheet in the first nip portion.

A fixing device includes an endless fixing belt, a heating roller that heats the fixing belt, a steering roller, and a pressurization rotating member. The steering roller is controlled to swing to move the fixing belt to a prescribed position. The pressurization rotating member pressurizes and forms a fixing nip portion with the fixing belt. When a recording material bearing unfixed toner is nipped and conveyed to the fixing nip portion, an unfixed toner image is fixed to the recording material. A single inclination operation that inclines the steering roller results in an inclination angle that is smaller when a recording material having a length greater than a predetermined length in a recording material conveying direction is conveyed to the fixing nip portion than when a recording material having a length less than or equal to the predetermined length in the conveying direction is conveyed to the fixing nip portion.

An image forming apparatus includes an image forming device, a heater, and a controller. The image forming device is configured to generate a laser scanning beam based on the image data to form a toner image on a sheet. The heater is configured to heat the sheet. The heater includes heater elements arranged in a direction corresponding to the main scanning direction of the laser scanning. The controller is configured to selectively control the heater elements to be energized at an energization start timing based on the image data and a signal from the image forming device indicating a start of scanning by the laser scanning beam in the main scanning direction.

A fixing apparatus includes a fixing belt, a steering roller, a pressure rotation member, and a contact-separation mechanism. The contact-separation mechanism moves the pressure rotation member to a position where the pressure rotation member is in a contact state with the fixing belt and a position where the pressure rotation member is in a separated state from the fixing belt. Swing of the steering roller is controlled so that the fixing belt moves to a predetermined position in a fixing belt width direction. A distance between a center position of the fixing belt in tilting the steering roller for a first time after the center position is separated from a center position of a range of movement of the fixing belt and the center position of the range of movement of the fixing belt in the width direction is smaller in the separated state than in the contact state.

In an image forming apparatus, a controller causes a first fixing member to heat up to a standby temperature Tr lower than a fixing temperature, through a control process executed from a state in which rotation of the first fixing member is stopped and a nip pressure is set at a second pressure smaller than a first pressure. The control process includes: a first process of activating and controlling a heater to cause the first fixing member to heat up toward a target temperature; a second process of starting the rotation of the first fixing member; a third process of changing the nip pressure from the second pressure to the first pressure; a fourth process of changing the nip pressure from the first pressure to the second pressure; and a fifth process of stopping the rotation of the first fixing member, executed in this sequence.

Provided is an electrophotographic belt of an endless shape including a substrate, wherein the substrate contains a polyimide resin and carbon nanotubes, wherein a content of the carbon nanotubes in the substrate is 15 vol % or less with respect to a total volume of the polyimide resin, wherein the substrate has a tensile strength of 200 MPa or more in each of a peripheral direction thereof and a direction perpendicular to the peripheral direction, and wherein the substrate has a thermal conductivity of 0.9 W/(m.Math.K) or more in a thickness direction thereof.

A belt includes a resin and an aggregate in which plural fibrous carbons are entangled with each other, in which a maximum diameter of the aggregate is 50% or less of a belt film thickness.