A heating device includes a base, a plurality of resistance heating elements, a power control circuit, a first temperature sensor, a second temperature sensor, and control circuitry. The resistance heating elements is disposed in a longitudinal direction of the base and electrically connected in parallel with each other. The power control circuit is configured to supply electrical power to the resistance heating elements. The control circuitry is configured to control an electrical power amount of the power control circuit so that temperatures of the resistance heating elements become equal to a first predetermined temperature based on a result of sensing with a first temperature sensor of the resistance heating elements and cut off the electrical power supplied from the power control circuit to the resistance heating elements in response to sensing of a second predetermined temperature with a second temperature sensor of the resistance heating elements.

A heating device includes a rotating unit, a transport belt, a heater, and a heat pipe. The rotating unit rotates. The transport belt rotates together with the rotating unit while nipping a heated member together with the rotating unit so as to transport the heated member. The heater has a contact surface in contact with an inner peripheral surface of the transport belt and a flat non-contact surface not in contact with the inner peripheral surface, and generates heat so as to heat the heated member via the transport belt. The heat pipe has a flat outer surface in contact with the non-contact surface of the heater and an interior having a cross-sectionally-circular space filled with a working fluid, and transfers heat in a belt width direction of the transport belt in accordance with a function of the working fluid.

An image forming apparatus includes a developing device accommodating toner, the toner containing:

a binder resin; and a coloring agent; and a fixing device configured to fix a toner image formed with the toner on a recording medium, the fixing device comprising: a tubular belt member; a heating member configured to heat the tubular belt member directly or indirectly in contact with the tubular belt member; and a pressing member in contact with the tubular belt member, wherein the toner under a load of 2 kg has a flow index Tf of from 70 to 121 degrees C., a flow index Te of from 83 to 120 degrees C., and a softening index Tw of from 65 to 80 degrees C.

Certain embodiments provide a fixing device, for fixing a toner image formed on an image receiving medium to the image receiving medium, including: a pressure rotation member; a pressure member against which the pressure rotation member is pressed across the image receiving medium; a heating roller separated from the pressure member and configured to rotate around a rotation axis thereof; an annular belt wound around the heating roller and the pressure member; a belt regulating member configured to include an opening into which the heating roller is loosely fitted and an abutting surface abutting against the annular belt; and a stopper arranged to face an outer edge of the annular belt contacting the heating roller across the belt regulating member.

A fixing device according to the present disclosure includes a heater, a rotating member heated by the heater, an endless belt, a nip forming member, and a sliding sheet. The nip forming member forms a nip portion by nipping the endless belt between the nip forming member and the rotating member. The sliding sheet has a first portion nipped between the endless belt and the nip forming member and a second portion extending from the first portion. The sliding sheet has higher flexural rigidity than the endless belt. The second portion has a bent portion bent so as to contact an inner circumferential surface of the endless belt. The bent portion configured to urge, in a direction directed from an inner side toward an outer side of the endless belt, a portion of the endless belt positioned downstream of the nip portion in the moving direction.

Certain embodiments provide a fixing device, for fixing a toner image formed on an image receiving medium to the image receiving medium, including: a pressure rotation member; a pressure member against which the pressure rotation member is pressed across the image receiving medium; a heating roller separated from the pressure member and configured to rotate around a rotation axis thereof; an annular belt wound around the heating roller and the pressure member; a belt regulating member configured to include an opening into which the heating roller is loosely fitted and an abutting surface abutting against the annular belt; and a stopper arranged to face an outer edge of the annular belt contacting the heating roller across the belt regulating member.

A heater for being attached to a heating device includes a base layer, a heat generator mounted on the base layer, an electrode mounted on the base layer, and a feeder mounted on the base layer. The feeder is interposed between the electrode and the heat generator. The feeder is configured to electrically connect the electrode to the heat generator. A positioner is configured to engage a counterpart of the heating device. The positioner is configured to position the heater in a longitudinal direction of the heater when the heater is attached to the heating device.

A heating device includes a heater and an interrupting portion. The heater extends in a width direction of a rotary belt and configured to contact and heat the belt. The interrupting portion is configured to interrupt power supply at a longitudinal end portion of the heater.

A heating device includes a base, resistance heating elements, a power control circuit, a first temperature detector, a second temperature detector, a power interrupter, and control circuitry. The resistance heating elements are arranged in a longitudinal direction of the base and electrically connected in parallel. The first detector detects a temperature of a first resistance heating element. The second detector detects a temperature of a second resistance heating element. The power interrupter interrupts power supplied to the resistance heating elements when the temperature of the second resistance heating element becomes a predetermined temperature or more. The control circuitry controls the circuit such that a temperature of each resistance heating element becomes a predetermined temperature, based on a result of detection of the first detector, and interrupts the power supplied to the resistance heating elements when the second detector detects predetermined temperature information regarding the second resistance heating element.

A fixing device includes a heating unit, a pressure unit, a moving unit, and a controller. The heating unit is configured to heat a toner on a recording medium. The pressure unit is configured to transport the recording medium while sandwiching the recording medium in a nip that the pressure unit and the heating unit form. The moving unit is configured to change a nip state of the pressure unit with respect to the heating unit by moving the heating unit or the pressure unit. The controller is configured to, when plural recording media are transported continuously, control the moving unit so that the moving unit moves the heating unit or the pressure unit in a separation direction so as to reduce a nip width at a recording medium interval between the recording media.