A fixing device includes a belt unit and an opposite member. The belt unit and opposite member are configured to, when a recording medium with a developer image transferred thereon passes through a nip region formed by the belt unit and opposite member, fix the developer image to the recording medium. The belt unit includes an endless belt, a heater group including a plurality of stacked heaters, and a holder that holds the heater group inside the belt.

A fuser device for fusing a developer image on a medium by applying heat includes an endless fuser belt, a belt supporting part that has a contact face shaped in an arc centering on a first central axis and contacts with the inner circumferential face of the fuser belt on the contact face, a driven ring that is disposed on at least one side of the fuser belt in the width direction of the fuser belt, and a ring supporting part that has a contact face shaped in an arc centering on a second central axis and contacts with an inner circumferential face of the driven ring on the contact face, wherein the first central axis is shifted from the second central axis.

A release sheet includes a support member including a positioning portion formed on a part, in a first direction along a longitudinal direction of the fixing belt, of the support member and configured to position the support member to a holding portion, that holds the fixing belt, in a second direction orthogonal to the first direction, and a release member fixed with the support member and including a front end portion that faces a surface of the fixing belt through a gap. One member among the support member and the release member includes an opening which is oblong in the second direction more than the first direction in order to adjust a distance between the front end portion and the positioning portion in the second direction.

A belt-type transport device includes a belt, a pressure unit, a nip forming unit, a belt stretching roller, an inclination controller, a contact unit, and a support unit. The belt is an endless belt, has an outer circumferential surface and an inner circumferential surface, and is to be rotated. The pressure unit is in contact with the outer circumferential surface of the belt. The nip forming unit presses the belt against the pressure unit so as to form a nip through which a recording medium is to be transported. The belt stretching roller is disposed inside the belt and stretches the belt. The inclination controller controls inclination of the belt stretching roller. The contact unit is provided along a width direction of the belt and is in contact with the inner circumferential surface of the belt. The support unit supports the contact unit such that the contact unit is able to follow inclination of the belt which is changed due to the inclination of the belt stretching roller.

Provided is a fixing member having an outer surface including excellent toner releasability and excellent scratch resistance, wherein the fixing member has a base material, an elastic layer, and a release layer in this order, the release layer including a tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer, and has a loss tangent at a frequency of 10 Hz and 180 C. of 5.010.sup.2 or more and 3.010.sup.1 or less.

A fixing apparatus includes a holding member including a groove-like holding portion, a heater supported by the holding portion, a film rotatable around the heater, the film being configured to be heated by sliding on the heater and to heat a toner image on a printing material, and a gap filling member including, on an upstream side with respect to the heater in a direction in which the circumferential surface of the film moves, a first portion disposed between the heater and the holding member and a first contact portion connecting to the first portion and being in contact with the film. A second distance between the first portion and the holding member disposed upstream from the first portion and facing the first portion is smaller than a first distance between the heater and the first portion disposed upstream from the heater and facing the holding member.

An image forming apparatus includes a control unit configured to perform a rubbing mode in which a rubbing rotatable member moves from a separation position to an abutment position in a state where a fixing belt is in a stop state. The control unit is configured to control a contact-and-separation mechanism in the rubbing mode such that if a predetermined temperature to which the fixing belt is heated is a first temperature, the rubbing rotatable member moves from the abutment position to the separation position at a timing when a first time has elapsed since the rubbing rotatable member abutted against the surface of the fixing belt, and if the predetermined temperature is a second temperature higher than the first temperature, the rubbing rotatable member moves from the abutment position to the separation position at a timing when a second time shorter than the first time has elapsed.

A belt-type transport device includes a belt, a pressure unit, a nip forming unit, a belt stretching roller, an inclination controller, a contact unit, and a support unit. The belt is an endless belt, has an outer circumferential surface and an inner circumferential surface, and is to be rotated. The pressure unit is in contact with the outer circumferential surface of the belt. The nip forming unit presses the belt against the pressure unit so as to form a nip through which a recording medium is to be transported. The belt stretching roller is disposed inside the belt and stretches the belt. The inclination controller controls inclination of the belt stretching roller. The contact unit is provided along a width direction of the belt and is in contact with the inner circumferential surface of the belt. The support unit supports the contact unit such that the contact unit is able to follow inclination of the belt which is changed due to the inclination of the belt stretching roller.

An image forming apparatus includes an image forming portion, a fixing unit, a position adjustment mechanism, a number-of-printed-sheets counter, and a control unit. The image forming portion includes an image carrier, a charging unit, an exposure unit, a developing unit, and a transfer member. The fixing unit has a heated rotary member and a pressing member and heats and presses the sheet passing through a fixing nip portion. A position adjustment mechanism adjusts the width-direction position of the sheet parallel to the scanning direction of optical scanning by the exposure unit. Every time the number of printed sheets reaches a predetermined number, the control unit makes the correction unit shift the width-direction position of the sheet by a predetermined amount and changes the start position of scanning by the exposure unit on the image carrier according to the direction and amount of shift.

An endless belt, a heat source, a rotatable member forming a nip together with a belt, a nip forming member which includes a first member having a U-shape made of metal and open on a side opposite from the rotatable member and which includes a second member provided inside the first member, a contact member contacting an inner peripheral surface of the belt, a reflecting portion for reflecting, toward the inner peripheral surface of the belt, radiation heat from the heat source toward the nip forming member, and a heat conducting portion, contacting the contact member, for conducting heat of the reflecting portion to the contact member, and a heat insulating member provided between the first member and the second member are provided, and a thickness t (m) and thermal conductivity (W/m.Math.K) satisfy:

t100 (m)

0.02 (W/m.Math.K)0.05 (W/m.Math.K).