A fixing device includes a hollow rotating body, a pressing member that applies pressure to a recording medium and transports the recording medium in a transport direction along with rotation of the rotating body, a heating member that is in contact with the rotating body while extending in an axial direction perpendicular to the transport direction, and a holding member that holds the heating member. The heating member includes a contact portion and non-contact portions, the contact portion has a first end portion on a downstream side of the contact portion in the transport direction, each non-contact portion has a second end portion on the downstream side in the transport direction, and each second end portion is thicker than the first end portion in a direction perpendicular to the transport and axial directions. The holding member is in contact with the second end portions in the transport direction.

A belt driving device includes plural rotating members around which a belt member extends, each rotating member rotating about a rotating shaft; and contact members disposed at both sides of the belt member in a width direction. The rotating members include a first rotating member, having a dimension less than a width of the belt member in a direction of the rotating shaft. Each contact member has a first contact point at which the contact member contacts the belt member and a second contact point closer to a corresponding one of the end portions in the width direction than the first contact point and at which the contact member contacts the belt member such that an angle between the contact member and the rotating shaft at the second contact point is greater than an angle between the contact member and the rotating shaft at the first contact point.

In a fixing device, a pressure unit is pressed toward a roller by an arm, to form a nip region. The pressure unit includes a belt configured to contact the roller in a nip region, a pressure pad configured to press the belt in combination with the roller, and a side guide including an end guide surface configured to guide a side end of the belt, and a stay configured to support the pressure pad. A supporting member is located on an outer side of the side guide that is opposite to an inner side on which the end guide surface faces. The supporting member is held between the stay and the arm, the supporting member comprising a contact surface which contacts the side guide and on which the side guide is swayably supported.

According to one embodiment, a belt positioning structure includes a belt roller around which an endless belt is wound. The belt comprises a belt-side positioning component curbing position aberration from the belt roller in a roller shaft direction. The belt roller comprises a roller-side positioning component curbing position aberration of the belt in a belt shaft direction. The roller-side positioning component comprises a regulation plate formed along a virtual tapered surface that has a diameter on one side in the roller shaft direction larger than a diameter on an opposite side of the regulation plate. The regulation plate comprises a movement regulation component that regulates movement of the belt-side positioning component to the one side of the belt-side positioning component in the roller shaft direction and strengthens a movement regulation force to the one side of the belt-side positioning component in the roller shaft direction.

A fixing device includes a hollow rotating body that rotates about an axis of the rotating body, a pressing member that applies, together with the rotating body, pressure to a recording medium and transports the recording medium in a transport direction along with rotation of the rotating body, a heating member that is disposed in such a manner as to be in contact with an inner surface of the rotating body while extending in an axial direction perpendicular to the transport direction and that heats the rotating body, the heating member including a contact portion at least a portion of which is brought into contact with the inner surface and non-contact portions that are positioned on either side of the contact portion in the axial direction in such a manner as not to be in contact with the rotating body and each of which has a second end portion thicker than a first end portion of the contact portion on a downstream side in the transport direction, and a holding member that holds the heating member by being brought into contact with at least the second end portions in the transport direction.

A belt driving device includes plural rotating members around which a belt member extends, each rotating member rotating about a rotating shaft; and contact members disposed at both sides of the belt member in a width direction. The rotating members include a first rotating member, having a dimension less than a width of the belt member in a direction of the rotating shaft. Each contact member has a first contact point at which the contact member contacts the belt member and a second contact point closer to a corresponding one of the end portions in the width direction than the first contact point and at which the contact member contacts the belt member such that an angle between the contact member and the rotating shaft at the second contact point is greater than an angle between the contact member and the rotating shaft at the first contact point.

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 includes a first roller having a first portion between tapered portions, which are at each end of the first portion. An outer diameter of each tapered portion decreases with distance from the first portion along a width direction of the first roller. A second roller has a second portion facing the first portion of the first roller and third portions, which are at each end of the second portion. The third portions face the tapered portions of the first roller. A belt of the image forming apparatus has an inner surface contacting the first portion of the first roller and an outer surface forming a nip with the second portion of the second roller. The belt has a protruding portion on the inner surface at each end of the belt in the width direction. The protruding portions face the tapered portions of the first roller.

A belt control device includes a plurality of rollers, a belt wound around the plurality of rollers and configured to rotate along with the plurality of rollers, a belt contact member that the belt contacts when the belt moves in an axial direction of the plurality of rollers, and a shaft displacement member movable in the axial direction and including an inclined face inclined with respect to a surface of the belt to control movement of the belt in the axial direction. The belt, the belt contact member, and the shaft displacement member are configured to make a frictional force between an edge of the belt and the belt contact member greater than a frictional force between the belt contact member and the shaft displacement member.

A belt driving device includes an annular belt member, rotary members, a protrusion, and a contact member. The belt member includes first and second edges. The belt member is wound around the rotary members. The protrusion protrudes from an inner peripheral surface of the belt member. The protrusion and each rotary member are arranged in an extending direction of the rotary member. The protrusion is provided at the second edge. The contact member is closer to the first edge. When the belt member deviates, the contact member comes into contact with the belt member. A difference between a position of the belt member when the protrusion comes into contact with an end surface of one of the rotary members and a position of the belt member when the belt member comes into contact with the contact member is equal to or less than a width of the protrusion.