A heating device includes a first rotator, a heater including a base and a heat generator, and a second rotator contacting the first rotator. The heat generator adjacent to the base defines a heat generation area having one edge close to one edge of the base in a longitudinal direction of the base. A length between the one edge of the base and the one edge of the heat generation area is longer than a length between the other edge of the base and the other edge of the heat generation area. The second rotator has one edge close to the one edge of the heat generation area. A length between the one edge of the second rotator and the one edge of the heat generation area is shorter than a length between the other edge of the second rotator and the other edge of the heat generation area.

According to one embodiment, a heater includes an insulating substrate, a heat generating section formed in the insulating substrate and including a plurality of divided regions in a longitudinal direction, temperature sensors detecting temperature of the heat generating section and a wiring pattern for power feed to the temperature sensors, each formed in a layer different from a layer in which the heat generating section is formed in the insulating substrate. The heat generating section, the temperature sensors, and the wiring pattern are layer stacked.

According to an embodiment, a heater includes a heat-resistant insulating substrate, a plurality of heat generating members arrayed on a first surface of the insulating substrate, and a heat radiating body disposed on a surface different from the first surface of the insulating substrate corresponding to gap portions among the plurality of heat generating members and configured to actively or passively radiate stored heat.

A heating device according to an embodiment generally includes heat generating parts and temperature sensors. The heat generating parts are divided into a plurality of blocks, so that the plurality of heat generating parts are arranged with a gap therebetween on a substrate in each block. With a temperature detection region provided in each block, the temperature sensors are provided corresponding to the heat generating parts with the gaps being avoided. The temperatures of the heat generating parts are detected by the temperature sensors that are less in number than the plurality of heat generating parts.

According to one embodiment, a heater has a base member, a heat generating resistor, a wiring and a switch. Three or more electrodes are disposed on the base member to be spaced apart from each other in a longitudinal direction of the base member. The heat generating resistor electrically interconnects electrodes which form an electrode pair and face each other in the longitudinal direction among the electrodes. The wiring connects the electrodes forming the electrode pair to have different polarities from each other. The switch is connected to the wiring and configured to select an electrode to which a voltage is to be applied.

There is provided a heater according to an embodiment including a heat generating unit configured to generate heat by electric conduct ion; and a plurality of electrodes configured to be respectively disposed at facing side edges of the heat generating unit so as to be electrically connected to the heat generating unit and at least one side of the side edges is formed by cutting out a part thereof.

According to one embodiment, a heater includes an insulator substrate, a heat generating section in which a plurality of divided regions are formed in a longitudinal direction on a first surface of the insulator substrate, electrodes formed at both end portions of the heat generating section to correspond to the plurality of divided regions, and electric conductors connected to at least one of the electrodes and formed over a surface different from the first surface of the insulator substrate.

A heater according to an embodiment generally includes resistive members and a first pole-side electrode. The plurality of resistive members are arranged in a first direction. The first pole-side electrode is connected to one ends of the resistive members in a second direction perpendicular to the first direction and configured to divide the plurality of resistive members into a plurality of blocks and to cause the plurality of resistive members to generate heat by the block. The first pole-side electrode includes a first pole-side first electrode provided in a first block including the resistive members arranged successively in the first direction, extending across the one ends of the resistive members in the first block, and connected to the one ends.

A heating device includes a heating rotator, a pressure rotator, a planar heater, and a holder. The pressure rotator is configured to press against the fixing rotator to form a nip through which the recording medium is conveyed. The planar heater includes a plurality of heat generators arranged side by side and at least one separation region between the plurality of heat generators. The holder holds the planar heater and contacts the planar heater in a pressure direction in which the pressure rotator presses the heating rotator. The holder includes at least one clearance structure configured to cause a contact area between the planar heater and a portion of the holder corresponding to the at least one separation region to be smaller than a contact area between the planar heater and a portion of the holder not corresponding to the at least one separation region.

A fixing device includes a nip formation pad which is disposed opposite an endless belt and forms a fixing nip between the endless belt and a pressure rotator. A contact heater is disposed at least at one lateral end of the nip formation pad in a longitudinal direction thereof and heats at least one lateral end of the endless belt in an axial direction thereof. A thermal conduction aid contacts a belt-side face of each of the nip formation pad and the contact heater and conducts heat in the axial direction of the endless belt. A cover is disposed outboard from the thermal conduction aid in a longitudinal direction thereof. The cover covers the belt-side face of the contact heater. The contact heater includes a power supply portion disposed outboard from the thermal conduction aid in the longitudinal direction thereof and covered by the cover.