The present invention provides a fixing device including a flexible cylindrical rotary member and an inner-surface opposing portion that opposes an inner surface of the rotary member at an end portion of the rotary member in a generatrix direction. The inner-surface opposing portion moves upstream in a recording material conveying direction in accordance with lateral shift of the rotary member in the generatrix direction. This restricts the lateral shift of the rotary member.

An image forming apparatus according to the present invention includes: a driver that presses and separates two rollers via a belt; a detector that detects a position of the belt in an axial direction of one roller of the two rollers; and a hardware processor that calculates, based on a detection result by the detector, a first movement amount of the position of the belt in the axial direction when the belt is made to travel for a predetermined time in a state where the two rollers are separated and a second movement amount of the position of the belt in the axial direction when the belt is made to travel for the predetermined time in a state where the two rollers are pressed.

An image forming apparatus includes a plurality of image forming portions, an intermediate transfer belt, a belt displacement detector, an attraction force changer, and a controller. The intermediate transfer belt is an endless belt wound around drive and driven rollers. The belt displacement detector detects displacement of the intermediate transfer belt in a rotation axis direction of the driven roller. The attraction force changer is operable to change electrostatic attraction force of the driven roller with respect to the intermediate transfer belt exerted on each of opposite end sides of the driven roller in the rotation axis direction thereof. When the belt displacement detector detects displacement of the intermediate transfer belt, the controller makes the attraction force changer increase the electrostatic attraction force of the driven roller with respect to the intermediate transfer belt exerted on a side opposite to a side toward which the displacement has taken place.

An image forming apparatus includes a plurality of image forming portions, an intermediate transfer belt, a belt displacement detector, an attraction force changer, and a controller. The intermediate transfer belt is an endless belt wound around drive and driven rollers. The belt displacement detector detects displacement of the intermediate transfer belt in a rotation axis direction of the driven roller. The attraction force changer is operable to change electrostatic attraction force of the driven roller with respect to the intermediate transfer belt exerted on each of opposite end sides of the driven roller in the rotation axis direction thereof. When the belt displacement detector detects displacement of the intermediate transfer belt, the controller makes the attraction force changer increase the electrostatic attraction force of the driven roller with respect to the intermediate transfer belt exerted on a side opposite to a side toward which the displacement has taken place.

A belt drive device includes a first pulley, a second pulley, a first bulging portion, a belt, and a pressing portion. The first bulging portion is formed along an outer periphery of the second pulley to bulge outward in a radial direction of the second pulley at a center of the second pulley in an axial direction of the second pulley. The belt is stretched between the first pulley and the first bulging portion. The pressing portion presses an outer peripheral surface of the belt at a center of the belt in a width direction of the belt.

A fixing apparatus includes a fixing belt, a pressing roller configured to form a nip by pressing the fixing belt and rotate the fixing belt, a bush configured to guide an edge of the fixing belt, and a meandering adjustment member configured to move a rotation shaft of the pressing roller in a direction perpendicular to an axis direction of the pressing roller. The fixing apparatus can be provided to an image forming apparatus.

A pair of pressure members are disposed at both ends of a pressure roller and rotatably support the pressure roller to press the pressure roller against a fixing roller including an elastic layer via a fixing belt. One of the pressure members that includes a fulcrum engaging section engaged with a rotation fulcrum at one end and is locked to a biasing member at a side opposite to the fulcrum engaging section is moved by a moving member in a direction intersecting a pressing direction of the pressure roller in a state where deformation of the elastic layer is regulated. Thus, a force acting on a fixing nip formed by the deformation of the elastic layer of the fixing roller is stabilized. As a result, the traveling performance of the fixing belt is stabilized, whereby the offset control can be performed with high accuracy.

Drive belt systems and methods thereof are disclosed. Drive belt systems and methods thereof include driving a continuous belt around a drive pulley member and an idler pulley member by the drive pulley member and transporting a transport unit and/or reciprocating carriage unit coupled to the continuous belt in a first direction away from the drive pulley member. Drive belt systems and methods thereof also include applying at least a force to the belt in a traverse direction thereto to direct a portion of the belt about the drive pulley member by a belt stretch management apparatus coupled to the transport unit and/or reciprocating carriage unit.

A belt rotating device includes: a meandering correction roller that is rotatably supported within a support frame and is one of a plurality of rollers that stretch an endless belt; a supporting portion that is provided at the support frame and supports a rotating shaft of the meandering correction roller so as to be able to incline the rotating shaft of the meandering correction roller in a one direction; a collar member that is provided on the rotating shaft of the meandering correction roller, contacts the side end of the endless belt in which meandering has occurred, and moves in an axial direction; and an inclination guide portion that is supported by the support frame and has an inclined surface downward and inclined with respect to the shaft of the meandering correction roller, in a position in which the contact portion of the collar member contacts the inclination guide portion.

The present invention provides a fixing device including a flexible cylindrical rotary member and an inner-surface opposing portion that opposes an inner surface of the rotary member at an end portion of the rotary member in a generatrix direction. The inner-surface opposing portion moves upstream in a recording material conveying direction in accordance with lateral shift of the rotary member in the generatrix direction. This restricts the lateral shift of the rotary member.