A fixing device includes a heater, a heater holding member, a stay sheet-metal, and a belt holding member. The stay sheet-metal includes a top plate and side plates and is configured to control a load applied to the heater holding member, the side plates extending respectively from opposite sides of the top plate in a short-length direction of the top plate, toward the heater holding member. The belt holding member holds the fixing belt such that the fixing belt can peripherally rotate, the belt holding member holding at least one end of the heater holding member in a longitudinal direction thereof and at least one end of the stay sheet-metal in a longitudinal direction thereof. The top plate of the stay sheet-metal is formed to extend to at least one end of the stay sheet-metal in the longitudinal direction thereof.

A heating device includes a cylindrical film a heater disposed inside the cylindrical film on an inner surface of the cylindrical film. The heater has a plurality of heating elements that are spaced from each other at intervals along an axial direction. A heat transfer member contacts the heater. The heat transfer member is arranged such that, in a first region of the heater that includes just a single one of the heating elements, contact between the heater and heat transfer member is greater than in a second region of the heater that includes an interval between a pair of adjacent heating elements.

A fixing device includes an endless fixing belt capable of rotational movement, a pressure roller that presses from the outside of the fixing belt, a nip forming member that is arranged on an inner circumference surface side of the fixing belt and forms a fixing nip region between the fixing belt and the pressure roller, a support member that supports the nip forming member from an opposite side to the fixing nip region, and a slide sheet provided between the fixing belt and the nip forming member. The support member includes two support portions. The slide sheet is fixed between the two support portions.

An image forming apparatus includes a pressure roller, a driver that drives the rotation of the pressure roller, an endless fuser belt, a pressing member that is provided inside of the fuser belt to be opposite to the pressure roller and forms a nip portion where the fuser belt and the pressure roller come into contact with each other, a adjustment mechanism that adjusts a pressing force that presses one of the pressure roller and the pressing member to the other, a detector that detects a rotational load of the fuser belt, and a pressing force controller that controls the adjustment mechanism such that the pressing force is higher in an overload state where the rotational load of the fuser belt is equal to or more than a predetermined value than in a normal state where the rotational load of the fuser belt is less than the predetermined value.

A fixing apparatus includes a first rotary member, a nip forming unit including a heater and a holder member, a second rotary member, and a support member. The holder member includes a first surface configured to support the heater and provided on the nip portion side of the holder member in an orthogonal direction orthogonal to both of a longitudinal direction and a short direction, a second surface provided on a side of the holder member opposite to the first surface in the orthogonal direction and configured to abut a first abutting portion of the support member and abut a second abutting portion of the support member, and a rib portion provided to project from the second surface and extend in the short direction throughout at least a range in the short direction where the first surface is provided.

A fixing device (50) includes a fixing belt (70), a pressure member (80), and a heating section (90). The heating section (90) faces an inner peripheral surface of the fixing belt (70). The heating section (90) includes a heater (HT), a first heat sensitive body (SM11), and a second heat sensitive body (SM21). The second heat sensitive body (SM21) differs from the first heat sensitive body (SM11). The heater (HT) has a first heater portion (AE1). The first heater portion (AE1) is one end portion of a pair of end portions of the heater (HT) in a longitudinal direction thereof. The first heat sensitive body (SM11) and the second heat sensitive body (SM21) face the first heater portion (AE1) and are aligned in a conveyance direction (DC) of a sheet (S).

A belt device includes a heater and a belt. The heater includes a substrate and a heat generator on the substrate. The heater has a first heater surface and a second heater surface opposite the first heater surface. The first heater surface is adjacent to the heat generator. The belt is rotatable, has an endless shape, and slides on the second heater surface. The belt includes an inner portion having an inner circumferential surface to slide on the second heater surface. The inner portion has an elastic power of 52% or more.

An image formation apparatus according to an embodiment includes a fixation device and a controller. The fixation device includes: a fixation member that includes a first region and a second region located closer to a center in a longitudinal direction of the fixation member than the first region; a pressurizing member that forms a nip portion between the fixation member and the pressurizing member; first and second heat generating portions that heat the first and second regions, respectively; a first sensor that detects a first temperature of one of the pressurizing member and the fixation member at a position corresponding to the first heat generating portion; and a second sensor that detects a second temperature of the one at a position corresponding to the second heat generating portion. The controller controls a drive speed of the pressurizing member or the fixation member based on the first and second temperatures.

A fixing apparatus includes a first rotary member, a heating element, a second rotary member, a nip member, a reflection member, and a support member. The support member configured to transit to a pressurized state and a non-pressurized state, the pressurized state being a state in which a first position and a second position of the support member are pressurized in a pressurization direction toward the second rotary member, the non-pressurized state being in which the pressurized state of the support member is released. The support member includes a contact surface in contact with the reflection member in the pressurized state. The contact surface takes such a posture that a center position between the first and second positions in the rotation axial direction is close to the second rotary member rather than the first and second positions in a case where the support member is in the non-pressurized state.

A fixing device includes a fixing belt, a pressure applying member, and a heater holding member. The fixing belt fixes toner to a sheet. The pressure applying member forms a nip portion together with an outer peripheral surface of the fixing belt and causes the fixing belt to peripherally rotate while applying pressure to the fixing belt at the nip portion. The heater holding member holds a heater that applies heat to the fixing belt. The heater holding member includes: a side portion that extends from the nip portion along an inner peripheral surface of the fixing belt and guides the fixing belt; and a plurality of inclined ribs that are disposed on the side portion to face the inner peripheral surface and formed such that an interval between them is gradually narrowed as they proceed in a direction in which the fixing belt peripherally rotates.