Abstract: A heater includes a plurality of resistive heat generators electrically connected to each other in parallel. A power supply supplies power to the resistive heat generators. An electric current detector detects an electric current that flows through the resistive heat generators. A voltage detector detects a voltage applied to the resistive heat generators. An electric current controller controls the electric current that flows through the resistive heat generators based on the electric current detected by the electric current detector and the voltage detected by the voltage detector. The electric current detector detects the electric current in a state in which, after the power supply starts supplying the power to the resistive heat generators, a waveform of an alternating current supplied to the resistive heat generators remains constant for a predetermined time period or longer taken for the electric current detector to detect the electric current.

Abstract: A heating device includes a heater and a holder. The heater includes a plate, an electrode disposed on one surface of the plate, and a heat generator. The heater does not include another electrode on the other surface of the plate opposite the one surface on which the electrode is disposed, and in a portion on the plate corresponding to the electrode. The holder includes a contact portion to contact the plate in a thickness direction of the plate, and at least one of a plurality of portions, a gap at a location corresponding to the electrode, existing between the plurality of portions and a single portion, at least a part of the single portion corresponding to the electrode, being relatively thinner than a part of the single portion corresponding to the heat generator.

Abstract: A heater includes a base, a plurality of heat generators arranged on the base in parallel to a longitudinal direction of the base, a plurality of electrodes on the base, and conductor paths disposed on the base. The conductor paths are electrically connected to the heat generators and the electrodes. The conductor paths include a main conductor path connected to one of the electrodes and a branch conductor path branched from the main conductor path. At least a part of the branch conductor path has a lower electrical resistance per unit length than an electrical resistance per unit length of the main conductor path.

Abstract: A fixing device includes an endless belt that rotates and a pressure rotator that rotates and presses against the endless belt to form a fixing nip between the endless belt and the pressure rotator, through which a recording medium bearing an image is conveyed. A heater is disposed inside a loop formed by the endless belt. The heater heats the endless belt. A conductor is disposed upstream from the pressure rotator in a recording medium conveyance direction and grounded. The conductor contacts and detects the recording medium.

Abstract: A heating device includes a heater, a holder configured to hold the heater, a. positioner configured to position the heater with respect to the holder in a longitudinal direction of the heater, a connector including a contact portion configured to contact an electrode of the heater. The heater includes a long base, a plurality of heat generators disposed on the base, three or more electrodes disposed on the base and electrically connected to the heat generators. The positioner is closer to the electrodes than a center position of the base in a longitudinal direction of the base.

Abstract: A heating device includes a sleeve-shaped flexible fixing rotator, a heater to contact an inner surface of the fixing rotator, a pressure rotator pressed against the heater via the fixing rotator to form a nip between the fixing rotator and the pressure rotator, a thermometer to detect a temperature of the heater, and a pressing force switching mechanism to switch a pressing force between the heater and the pressure rotator. The pressing force switching mechanism switches the pressing force between the heater and the pressure rotator in at least two stages, a standard force when the temperature of the heater detected by the thermometer increases and reaches a predetermined temperature and before the medium to be heated passes through the nip, and a reduced force smaller than the standard force when the temperature of the heater detected by the thermometer is lower than the predetermined temperature.

Abstract: A heating device includes a heater that heats an object to be heated. A holder supports the heater and includes an engaged portion. The heater includes a contact face that contacts the object to be heated. The heater further includes a separation restrictor that engages the engaged portion of the holder to restrict motion of the heater in a separating direction in which the heater separates from the holder. The separating direction is perpendicular to the contact face.

Abstract: A fixing device includes a first rotator, a second rotator disposed opposite the first rotator to form a nip with the first rotator, a heater including a base and a heat generator, and a non-contact temperature detector to detect a temperature of the heater. The heater contacts an inner circumferential surface of the first rotator. The non-contact temperature detector is disposed opposite the inner circumferential surface of the first rotator via the base and disposed at a predetermined distance from the heater.

Abstract: 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.

Abstract: An image forming apparatus includes a resistive heat generator, a temperature detector, and a power controller that detects a temperature-resistance property of the resistive heat generator before the resistive heat generator is used when the resistive heat generator is removably installed. The power controller obtains power supplied to the resistive heat generator and a change in a temperature of the resistive heat generator, that is detected by the temperature detector, while the power controller supplies the power at a predetermined power duty cycle for adjustment to the resistive heat generator. The power controller calculates the temperature-resistance property of the resistive heat generator based on the power and the change in the temperature that are obtained. The power controller adjusts a power duty cycle at which the power is supplied to the resistive heat generator in use of the resistive heat generator, based on the temperature-resistance property.

Abstract: 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.

Abstract: A heater includes a base and at least one resistive heat generator mounted on a face of the base. At least one electrode supplies power to the at least one resistive heat generator. A conductor couples the at least one electrode with the at least one resistive heat generator. A slide layer covers the at least one resistive heat generator and the conductor. The slide layer includes a projecting portion that defines a surface of the slide layer. The projecting portion is defined by a film thickness of at least one of the conductor and the at least one resistive heat generator. The projecting portion includes an upstream projection disposed opposite a lateral end of the base in a longitudinal direction of the base and a downstream projection disposed downstream from the upstream projection in a rotation direction of an endless belt that slides over the heater.

Abstract: A heating device includes an endless rotator that rotates in a rotation direction. A heater contacts the endless rotator. An elastic body is disposed opposite an inner circumferential surface of the endless rotator and disposed downstream from the heater in the rotation direction of the endless rotator. A holder holds the heater and the elastic body. A pressure rotator is disposed opposite the heater and the elastic body via the endless rotator to form a nip between the endless rotator and the pressure rotator. A slide sheet covers a surface of the elastic body. The slide sheet includes an upstream end in the rotation direction of the endless rotator. The upstream end is sandwiched between the heater and the elastic body and between the elastic body and the holder. The upstream end is secured to the holder.

Abstract: A heater includes a base layer, a heat generator mounted on the base layer, and a slide layer mounted on the base layer. A sliding face of a counterpart slides over the slide layer. The slide layer is made of a material containing fluorine and includes a slide face that contacts the sliding face of the counterpart. The slide face of the slide layer has a surface roughness that is greater than a surface roughness of the sliding face of the counterpart.

Abstract: A fixing device includes an endless belt that rotates and a pressure rotator that rotates and presses against the endless belt to form a fixing nip between the endless belt and the pressure rotator, through which a recording medium bearing an image is conveyed. A heater is disposed inside a loop formed by the endless belt. The heater heats the endless belt. A conductor is disposed upstream from the pressure rotator in a recording medium conveyance direction and grounded. The conductor contacts and detects the recording medium.

Abstract: A heater includes a base and at least one resistive heat generator mounted on a face of the base. At least one electrode supplies power to the at least one resistive heat generator. A conductor couples the at least one electrode with the at least one resistive heat generator. A slide layer covers the at least one resistive heat generator and the conductor. The slide layer includes a projecting portion that defines a surface of the slide layer. The projecting portion is defined by a film thickness of at least one of the conductor and the at least one resistive heat generator. The projecting portion includes an upstream projection disposed opposite a lateral end of the base in a longitudinal direction of the base and a downstream projection disposed downstream from the upstream projection in a rotation direction of an endless belt that slides over the heater.

Abstract: A heating device includes an endless rotator that rotates in a rotation direction and a heater that contacts an inner circumferential surface of the endless rotator and extends in an axial direction of the endless rotator. An elastic body contacts the inner circumferential surface of the endless rotator and is disposed downstream from the heater in the rotation direction of the endless rotator. A holder holds the heater and the elastic body. A pressure rotator is disposed opposite the heater and the elastic body via the endless rotator to form a nip between the endless rotator and the pressure rotator. A motion restrictor is mounted on the holder. The motion restrictor restricts motion of the heater downstream in the rotation direction of the endless rotator.

Abstract: An image forming apparatus includes a heating device including a heat generator and a resistance value identifier, a body, a resistance value acquisition unit, a detector to detect detachment and attachment of the heating device from and to the body, and an electric power controller. The resistance value identifier corresponds to a resistance value of the heat generator. The resistance value acquisition unit acquires the resistance value from the resistance value identifier. The electric power controller causes the resistance value acquisition unit to acquire the resistance value when the detector detects detachment and attachment of the heating device. The electric power controller changes a lighting duty of the heat generator when the acquired resistance value of the heat generator is different from the resistance value before the detector detects detachment and attachment of the heating device.

Abstract: A heating device includes a belt that rotates in a rotation direction and has a temperature decrease span in an axial direction of the belt, where the belt is susceptible to temperature decrease. A resistive heat generator is disposed opposite the belt. The resistive heat generator heats the belt and extends in the axial direction of the belt. The resistive heat generator includes a primary heat generating portion that generates heat in a first heat generation amount and a secondary heat generating portion that is disposed outside the primary heat generating portion and disposed opposite the temperature decrease span of the belt. The secondary heat generating portion generates heat in a second heat generation amount that is greater than the first heat generation amount of the primary heat generating portion.

Abstract: A fixing device includes a heater including a heat generator that is divided into a plurality of heat generating portions in an axial direction of the endless belt. The heat generator defines a dividing region between adjacent ones of the plurality of heat generating portions and a non-dividing region other than the dividing region. A primary guide contacts and guides the endless belt. The primary guide is disposed opposite the dividing region of the heat generator and has a first thermal capacity. A secondary guide contacts and guides the endless belt. The secondary guide is disposed opposite the non-dividing region of the heat generator and has a second thermal capacity that is greater than the first thermal capacity.