An image forming apparatus includes a fixing member, a heating portion configured to heat the fixing member by being supplied with electric power, a power source configured to supply electric power to the heating portion, a temperature detector, a controller configured to control power supply from the power source to the heating portion based on the output voltage from the temperature detector, a reference voltage generator configured to generate a reference voltage, and a breaker configured to stop the power supply from the power source to the heating portion. The reference voltage generator is configured to output the reference voltage that changes with time having elapsed since a start of heating at which the power supply to the heating portion was started by the controller.

A fixing apparatus includes an endless first rotary member, a heating element, a second rotary member configured to form a nip portion, and a nip member configured to receive radiant heat from the heating element and heat the nip portion. The nip member includes a main-body portion that contains aluminum or aluminum alloy and a protective layer that includes an oxide film formed on a surface of the main-body portion. The main-body portion contains a heat receiving surface that faces the heating element and receives radiant heat from the heating element, and a rubbed surface that is rubbed against the inner circumferential surface of the first rotary member. The protective layer contains coloring agent that causes an emissivity of the heat receiving surface and the rubbed surface to be higher than an emissivity of a natural color oxide film.

An image heating device heats up an image formed on a recording material, the device having: a heating member provided with a heater having a plurality of heating elements juxtaposed in a direction perpendicular to a conveyance direction of the recording material; a roller, such that the circumference of the roller increases from a central portion towards ends portions, in a direction perpendicular to the conveyance direction; and a control portion that controls individually the power supplied to the plurality of heating elements. The control portion sets a control target temperature, being set in order to supply power to a heating element corresponding to a non-sheet passing area, from among the plurality of heating elements, to be higher than a lowest control target temperature from among control target temperatures that are set in order to supply power to a heating element corresponding to a sheet passing area.

A fixing belt includes: a base having an endless shape; and a resin layer covering a surface on an inner peripheral side of the base, the resin layer comprising a resin and a filler, and having a second surface opposite to a first surface facing the base, the second surface having cell structures, and being roughened with the filler. When arithmetic mean roughnesses of the second surface in the central region X and the end regions Y and Z are defined as RaX, RaY and RaZ respectively, a difference between RaX and RaY, a difference between RaY and RaZ, and a difference between RaX and RaZ are all 0.1 μm or smaller, and a coefficient of variation of areas of the cell structures contained in each of the central region X, and end regions Y and Z is 25% or smaller.

A fixing device includes a tubular body in a tubular shape that forms a nip with a pressurizing member. The heater, disposed inside the tubular body, faces a part of the tubular body in a circumferential direction. The heat equalizing member is disposed on an opposite side of a side where the heater faces the tubular body. The heat equalizing member transfers heat from a place having a high temperature to a place having a low temperature in a second direction along an axial direction of the tubular body. The heat conductive member, disposed between the heater and the heat equalizing member, can conduct the heat in each of the second direction and a first direction in which the heater and the heat equalizing member face each other. A side portion of the heat conductive member in the second direction is divided into three or more portions.

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.

According to one embodiment, a temperature control device includes a temperature estimation unit and a frequency generation unit. The temperature estimation unit is configured to estimate a temperature of an object being heated by an induction heating coil, the temperature being estimated based on a frequency of a drive signal supplied to an inverter connected to the induction heating coil. The frequency generation unit is configured to set the frequency of the drive signal based on the temperature estimated by the temperature estimation unit, a detected temperature of the object from a temperature sensor, and a target temperature for the object.

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 disclosed fixing device includes a pressing member; an endless tubular fixing member disposed opposite to the pressing member; a heating source configured to heat the fixing member; a nip forming member disposed opposite to the pressing member via the fixing member to form a nip portion; and a supply unit configured to supply lubricant to a portion of an inner surface of the fixing member, the portion facing the nip forming member, wherein the nip forming member includes a contact portion that contacts the inner surface of the fixing member, the contact portion includes a guide portion for guiding lubricant, and the guide portion is formed by extending obliquely from opposite ends in a width direction toward a center of the fixing member as the contact portion moves from upstream to downstream in a rotational direction of the fixing member.

According to one embodiment, a fixing device includes a belt, a heater, and a holder. The holder has a plurality of support portions that contact an end of the first heating region and an end of the second heating region along the direction perpendicular to the transport direction, and a plurality of non-contacting portions that do not contact the end of the first heating region and the end of the second heating region between the plurality of support portions, the end of the second heating region contacts one of the plurality of support portions at a side in the direction perpendicular to the transport direction, and the end of the second heating region faces to one of the plurality of non-contacting portions at the other side in the direction perpendicular to the transport direction.