Abstract: 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.

Abstract: A heating device (9) includes a heater (22), a holder (23), a device frame (40), a primary positioner (A), a secondary positioner (B), and a tertiary positioner (C). The heater includes a heat generator (60). The holder holds the heater. The device frame is configured to support the holder. The primary positioner is configured to position the heater and the holder in a longitudinal direction of the heater. The secondary positioner is configured to position the holder and the device frame in the longitudinal direction of the heater. The tertiary positioner is configured to position the device frame and a body of an image forming apparatus in the longitudinal direction of the heater. The primary positioner and one of the secondary positioner and the tertiary positioner are disposed on an identical side defined by a center of the heat generator in the longitudinal direction of the heater.

Abstract: 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.

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 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.

Abstract: A heater for being attached to a heating device includes a base layer and a heat generator, an electrode, and a feeder that are 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. The base layer includes a heat generating portion mounting the heat generator and an electrode portion mounting the electrode. A decreased cross section portion is interposed between the heat generating portion and the electrode portion. The decreased cross section portion has a cross-sectional area that is smaller than a cross-sectional area of the heat generating portion. The decreased cross section portion includes a positioner configured to engage a counterpart of the heating device and position the heater in a longitudinal direction of the heater when the heater is attached to the heating device.

Abstract: A heater includes a first heat generator and a second heat generator each of which has a hypothetical center line that divides each of the first heat generator and the second heat generator into a first section and a second section. A first conductor connects a first electrode to the first heat generator and the second heat generator. A second conductor connects a second electrode to the first heat generator and the second heat generator. A first primary connector connects the first conductor to the first section of the first heat generator. A second primary connector connects the first conductor to the second section of the second heat generator. A first secondary connector connects the second conductor to the first heat generator. A second secondary connector connects the second conductor to the second heat generator.

Abstract: A belt heating device includes an endless belt and a heater that heats the endless belt and includes a heat generator. A driving roller contacts the endless belt. A driving force transmitter is disposed at a lateral end of the driving roller in an axial direction thereof. The driving force transmitter transmits a driving force that drives and rotates the driving roller. The driving force transmitter is disposed in a driving side defined by a center of the heat generator in a longitudinal direction of the heater. A counterpart is disposed opposite the heater. A positioner positions the heater with respect to the counterpart in the longitudinal direction of the heater. The positioner is disposed in a positioning side defined by the center of the heat generator in the longitudinal direction of the heater. The positioning side is opposite the driving side in the longitudinal direction of 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 resistive heat generator and a power control device that controls power supplied to the resistive heat generator. The power control device supplies the power at a predetermined power duty cycle for adjustment to the resistive heat generator. The power control device adjusts a power duty cycle when the resistive heat generator is used.

Abstract: A heating device includes a heater, a holder, a connector, and a guide pair. The heater includes an electrode through which power is conducted. The holder is configured to hold the heater. The connector includes a conduction terminal and an engagement portion. The conduction terminal is configured to contact the electrode. The engagement portion is configured to be engaged with the holder. The connector is attachable to the holder to engage the engagement portion with the holder and contact the conduction terminal with the electrode. The guide pair includes a convex portion and a recess. The convex portion is disposed in one of the holder and the connector. The recess is disposed in another one of the holder and the connector. The guide pair is configured to guide the connector in an attaching direction of the connector to attach the connector to the holder.

Abstract: An image forming apparatus includes a cooler and a heater. The heater includes a heat generation unit, which includes resistive heat generators arranged in a longitudinal direction of the heater, a first electrode, a second electrode, a first conductor that connects the resistive heat generators in parallel with each other to the first electrode, and a second conductor that connects the resistive heat generators in parallel with each other to the second electrode. The first and second conductors are connected to at least one of the resistive heat generators on a first longitudinal end side of the heater from a center of the resistive heat generator in the longitudinal direction of the heater. A cooling ability of the cooler to a second longitudinal end side of the heater opposite the first longitudinal end side of the heater is greater than that to the first longitudinal end side of the heater.

Abstract: An image forming apparatus includes a cooler and a heater, which includes a heat generation part including resistive heat generators, a first electrode, a second electrode, a first conductor, a second conductor, and a branch channel. The first conductor connects the resistive heat generators and the first electrode. The second conductor extends from the resistive heat generators to a side in a first longitudinal direction of the heater to be connected to the second electrode. The branch channel branches from the second conductor and extends to a side in a second longitudinal direction opposite the first longitudinal direction to be connected to either the second conductor or the second electrode without passing through the first conductor. A cooling ability of the cooler to an end side of the heater in the second longitudinal direction is greater than that to an end side of the heater in the first longitudinal direction.

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 temperature detector for being positioned with respect to a counterpart includes a temperature detecting element that detects a temperature of a detecting target and a holding body that holds the temperature detecting element. A projecting engagement engages the counterpart and is mounted on the holding body.