An image forming apparatus includes an image forming portion configured to form a developer image on a recording material, a fixing portion configured to heat-fix the developer image to the recording material, a first motor configured to drive the image forming portion, a second motor configured to drive the fixing portion, and a control portion configured to control the first motor and the second motor. The second motor is a stepping motor. The control portion allows the second motor to start rotation at a speed in a self-start region, temporarily stops the second motor at a timing at which the first motor is activated, then allows the second motor to restart rotation at a speed in the self-start region, and changes the speed of the second motor to a speed outside the self-start region before the recording material arrives at the fixing portion.

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.

An example image forming apparatus includes an endless belt to rotate, belt rollers including a tension roller and an adjustment roller extending inside the endless belt, a nip roller extending adjacent the endless belt to form a nip between the nip roller and the endless belt, and a cam shaft that includes a nip forming cam and a tension adjustment cam. The nip forming cam moves the nip roller between a pressed position in which the nip roller is pressed against the endless belt, and a retracted position in which the nip roller is retracted from the endless belt. The tension adjustment cam moves the adjustment roller relative to the tension roller.

An image forming apparatus includes an endless belt to rotate, belt rollers including a tension roller and an adjustment roller extending inside the endless belt, a nip roller extending adjacent the endless belt to form a nip between the nip roller and the endless belt, and a cam shaft that includes a nip forming cam and a tension adjustment cam. The nip forming cam moves the nip roller between a pressed position in which the nip roller is pressed against the endless belt, and a retracted position in which the nip roller is retracted from the endless belt. The tension adjustment cam moves the adjustment roller relative to the tension roller.

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.

A fixing device includes a pair of fixing members disposed to face each other in a fixing area, a movable member movably supporting at least one of the fixing members between first and second positions, a driving device including a contact member and a drive source to move the movable member between the first and second positions, and a controller that controls the driving device, and if a temperature of the one of the fixing members is equal to or higher than a preset temperature when the driving device moves the movable member from the second position to the first position, changes the control to make driving force constantly exceed a rotational load of the driving device in accordance with advancement of a time of increase in the rotational load as compared with when the temperature of the one of the fixing members is lower than the preset temperature.

A fixing device includes a fixing belt that is endless and rotatable in a rotation direction and a nip former stretching the fixing belt. A pressure rotator presses against the nip former via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator, through which a recording medium is conveyed. A presser is disposed downstream from an exit of the fixing nip in a recording medium conveyance direction. The presser brings the fixing belt into contact with the pressure rotator. A gap retainer contacts the nip former and is coupled to the presser to retain isolation of the presser from the nip former.

A fixing device includes a fixing belt that is endless and rotatable in a rotation direction and a nip former stretching the fixing belt and including an elastic layer as a surface layer. A pressure rotator presses against the nip former via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator, through which a recording medium is conveyed. A presser is disposed downstream from an exit of the fixing nip in a recording medium conveyance direction. The presser brings the fixing belt into contact with the pressure rotator.

A fixing device includes a fixing belt that is endless and rotatable in a rotation direction and a nip former stretching the fixing belt. A pressure rotator presses against the nip former via the fixing belt to form a fixing nip between the fixing belt and the pressure rotator, through which a recording medium is conveyed. A presser is disposed downstream from an exit of the fixing nip in the rotation direction of the fixing belt. The presser brings the fixing belt into contact with the pressure rotator. A mover is coupled to the presser to move the presser between a contact position where the presser brings the fixing belt into contact with the pressure rotator and an isolation position where the presser isolates the fixing belt from the pressure rotator.

An image forming apparatus includes a heating unit that heats a recording material, a contact member that is positioned upstream or downstream from the heating unit in a transport direction of the recording material and is in contact with the recording material, the contact member being configured in such a manner that a portion of the contact member that is in contact with the recording material moves with the recording material, a temperature detection unit that detects a temperature of the contact member, and a control unit that controls, based on a detection result obtained by the temperature detection unit, an output of the heating unit.