An edge regulating member provided in a belt rotation device that tensions a belt via a belt tensioning roller and rotates the belt in a rotation direction includes a body that comes into contact with an inner surface of the belt and a regulating portion that extends, at a position adjacent to the body, further outward in a radial direction of the belt tensioning roller than the body, and comes into contact with an edge of the belt. Tension of the belt acting on the body while the inner surface of the belt is in contact with the body causes the regulating portion to tilt, turned outward in the rotation axis direction from a fold-back portion of the belt toward an upstream side in the rotation direction.

A flexible belt is disclosed for use in a printing system. The belt comprises an endless strip which, in use, travels along a continuous path. Formations are provided along the sides of the strip which are capable of engaging with lateral tracks to place the belt under lateral tension, the lateral tracks further serving to constrain the belt to follow the continuous path.

An image forming apparatus including a belt wound around a plurality of rollers, and a restriction portion disposed outside a specific roller of the plurality of rollers in a rotational axis direction of the specific roller, the restriction portion being configured to restrict movement of the belt in the rotational axis direction by contacting an end surface of the belt in the rotational axis direction, the belt having a first outer circumferential surface of an end portion of the belt in the rotational axis direction, the end portion including the end surface contactable with the restriction portion, and a second outer circumferential surface of a middle portion of the belt in the rotational axis direction, the first outer circumferential surface being positioned outside the second outer circumferential surface in a radial direction of the specific roller, the first outer circumferential surface being parallel to the second outer circumferential surface.

A fixing device includes a cylindrical film; a pressing member, and a preventing member including a preventing surface configured to prevent movement of the film in a longitudinal direction and a film rotation guiding surface. As viewed in the longitudinal direction of the film, the preventing surface includes first and second regions positioned downstream and upstream, respectively, of a nip center line with respect to a recording material feeding direction. The first region retracts from a longitudinal film end surface relative to the second region. The second region continuously extends in the recording material feeding direction from a portion upstream of a nip center line to a portion downstream of the nip center line, and has a length, with respect to a rotational direction of the film, longer at the portion upstream of the nip center line than at the portion downstream of the nip center line.

A flexible belt is disclosed for use in a printing system. The belt comprises an endless strip which, in use, travels along a continuous path. Formations are provided along the sides of the strip which are capable of engaging with lateral tracks to place the belt under lateral tension, the lateral tracks further serving to constrain the belt to follow the continuous path.

A belt unit includes: a belt member; a roller rotatably placed on an inner peripheral surface of the belt member; and a meander restraint member facing an edge portion of the belt member and configured to restrain the belt member from meandering while the belt member is running. The edge portion of the belt member includes a modification layer.

A flexible belt is disclosed for use in a printing system. The belt comprises an endless strip which, in use, travels along a continuous path. Formations are provided along the sides of the strip which are capable of engaging with lateral tracks to place the belt under lateral tension, the lateral tracks further serving to constrain the belt to follow the continuous path.

A flexible belt is disclosed for use in a printing system. The belt comprises an endless strip which, in use, travels along a continuous path. Formations are provided along the sides of the strip which are capable of engaging with lateral tracks to place the belt under lateral tension, the lateral tracks further serving to constrain the belt to follow the continuous path.

A flexible belt is disclosed for use in a printing system. The belt comprises an endless strip which, in use, travels along a continuous path. Formations are provided along the sides of the strip which are capable of engaging with lateral tracks to place the belt under lateral tension, the lateral tracks further serving to constrain the belt to follow the continuous path.

A belt unit includes: a belt member; a roller rotatably placed on an inner peripheral surface of the belt member; and a meander restraint member facing an edge portion of the belt member and configured to restrain the belt member from meandering while the belt member is running. The edge portion of the belt member comprises a modification layer.