A cylindrical fixing member for use with a fixing device includes a heat generating layer and an electrode layer contacting the heat generating layer. The electrode layer is smaller in volume resistance value than the heat generating layer. The electrode layer is formed in a helical shape so that a helical axis thereof extends in a direction along a generatrix direction of the fixing member. One end and the other end of the electrode layer are electrically open.

A heating system includes a heater, a current sensor outputting a current monitoring signal indicating a current level of an alternating current power signal, and a switch providing alternating current to the heater. The heating system also includes a controller that controls operation of the switch. The controller activates the switch during a portion of a half cycle of the alternating current power signal having increasing amplitude. Upon the current monitoring signal reaching a predetermined threshold within the half cycle, the controller deactivates the switch. The heating system is useable within an image forming apparatus.

A heating system includes a heater, a switch providing alternating current to the heater, and a current sensor electrically connected between the switch and the heater. The heating system also includes a controller that controls operation of the switch. The controller activates the switch during a portion of a half cycle of the alternating current having increasing amplitude under a threshold. The controller determines, based on a signal received from the current sensor during the activation of the switch, a time period from the start of the half cycle to a threshold timing at which the alternating current reaches the threshold. The controller reactivates the switch at a timing on or after a timing obtained by subtraction of the determined time period from an end of the half cycle. The heating system is useable within an image forming apparatus.

An imaging device includes a controller and fuser assembly. The fuser assembly has a heat transfer and backup member defining a nip and process direction of media travel. The heat transfer member includes a resistive trace with a length twice extending transverse to the process direction. The controller selectively applies AC power to the resistive trace. The controller calculates a power level from zero power to full power to heat the trace to a predetermined set-point temperature from a measured current temperature. The controller maps the calculated power level to one of only eight actual heating power levels that become applied or not to the resistive trace to achieve a desired power flicker and harmonics response otherwise unattainable by merely applying the calculated power level. The actual heating power levels include differing numbers of consecutive half-cycles of AC power and are applied at zero-crossings thereof.

A fuser, having a heater in a form of a planar plate and a holder supporting the heater, is provided. The heater has a first face and a second face opposite to the first face. The holder has a supporting base supporting the first face of the heater, a side wall protruding from the supporting base, a first contact portion, and a second contact portion. The first contact portion is located in an end area on one side in a lengthwise direction of the holder. The first contact portion protrudes from the side wall and contacts the second face of the heater. The second contact portion is located apart from the first contact portion in the lengthwise direction in an end area on the other side of the holder in the lengthwise direction. The second contact portion protrudes from the side wall and contacts the second face of the heater.

Provided is a heater that is excellent in heat equalizing property even when being narrow in a sweep direction. Also provided are a fixing device, an image-forming device, and a heating device each including such a heater. A heater is configured to heat an object to be heated in such a manner that at least one of the object to be heated and the heater is swept with the heater disposed opposite the object to be heated. The heater includes a base having a rectangular shape and a plurality of heating cells each independently receiving power supply, the heating cells being disposed on the base and arranged in a longitudinal direction of the base. Each of the heating cells includes a plurality of lateral wires extending in substantially parallel with the longitudinal direction of the base and a plurality of oblique wires tilted relative to the lateral wires.

An image heating apparatus includes a plurality of heat generating elements, a plurality of temperature detecting elements, and an energization controlling portion for selectively controlling, based on the temperature detected by each of the plurality of temperature detecting elements, electrical power to be supplied to the plurality of heat generating elements. The plurality of temperature detecting elements are arranged in each of the plurality of heat generating elements, and the energization controlling portion controls electrical power supply to the plurality of heat generating elements for the purpose of heating a non-sheet-passing heating region, through which a recording material does not pass, among the plurality of heating regions, based on a temperature detected by a temperature detecting element that is farthest from a conveyance reference position of the recording material, among the plurality of temperature detecting elements arranged in the non-sheet-passing heating region.

A heating device capable of suppressing electrically conductive parts that electrically connect power supply electrodes and heating resistors from generating heat. The heating device has heating resistors disposed in a longitudinal direction of an elongated base plate and connected through electrically conductive parts to power supply electrodes disposed on one longitudinal end portion of the base plate and supplied with electric power from the power supply electrodes. The electrically conductive parts are formed such that electrically conductive parts that can provide larger amounts of power supply each have a larger cross-sectional area perpendicular to a power supply direction.

An image forming apparatus includes a fixing unit having a heater, an energization control unit configured to control energization to a first heat generation member of the heater depending on a temperature detected by a temperature detection element of the fixing unit, a resistance detecting unit configured to detect a resistance of a second heat generation member of the heater, and a temperature acquiring unit configured to acquire a temperature of the heater in the region in which the second heat generation member is formed based on the resistance detected by the resistance detecting unit. An image, formed on a recording material, is fixed to the recording material with heat form the heater.

An image heating apparatus includes a cylindrical film, and a heater having a substrate, and a heat generating element provided on the substrate. The heater has an elongated plate-like shape, and a first surface contacting the film, a second surface opposite to the first surface, and a heater lateral surface facing outwardly in a widthwise direction of the heat generating element. A supporting member supports the heater, and includes a recess and a supporting lateral surface that is parallel to and opposes the heater lateral surface. The supporting lateral surface is provided in the recess, and is bonded to the heater lateral surface using an adhesive material. A high heat conduction member has a thermal conductivity greater than a thermal conductivity of the substrate, and contacts the second surface of the heater and is sandwiched between the heater and the supporting member.