An image forming apparatus includes a first rotating member, a heater, a second rotating member, a detecting unit, a switching unit, a controlling unit, and a power source device. In a first period, a resultant current of first and third currents is supplied to a first heat generating element, and the resultant current in a unit cycle of a first period is a current at which a first current supplying timing and timings of a maximum and a minimum of the third current do not overlap with each other. In a second period, a resultant current of second and third currents is supplied to a second heat generating element, and the resultant current in a unit cycle of the second period is a current at which a second current supplying timing and the timings of the maximum and the minimum of the third current overlap with each other.

Disclosed is a layer transfer device which transfers a layer of a multilayer film onto a surface of a sheet. The layer transfer device includes a heating member including a first portion and a second portion, a first heater, a second heater, and a controller. The controller is configured to control the first heater with an input power set at a predetermined input power, control the second heater with an input power set at a first input power if both of the multilayer film and the sheet pass over a surface of the second portion, and control the second heater with an input power set at a second input power that is smaller than the first input power if at least one of the multilayer film and the sheet does not pass over the surface of the second portion.

An image forming apparatus includes a control unit configured to, in executing a job to form images continuously on a plurality of sheets of a recording material, accumulate an addition amount per sheet to an index in accordance with a number of sheets of the recording material to which images are formed in the job. A value of the addition amount per sheet is determined in correspondence with an attribute of the recording material used in the job. The control unit is configured to, during execution of the job, change a throughput of the job so that images are formed at a first throughput if an accumulated value of the index still does not exceed a predetermined threshold value and images are formed at a second throughput slower than the first throughput if the accumulated value of the index has exceeded the threshold value.

An image forming apparatus includes a control unit configured to execute a first mode and a second mode. The first mode is a mode in which a toner image is formed on a sheet at a time when a sheet passes through an image formation position for a first time after detecting a property of the sheet by a detection unit. Wherein the second mode is a mode in which a toner image is not formed on a sheet at the time when the sheet passes through the image formation position for the first time after detecting the property of the sheet by the detection unit and is formed on the sheet at a time when the sheet is conveyed via the second conveyance path and passes through the image formation position for a second time.

An image heating device includes a heater having a plurality of heating elements that heat a plurality of heating regions and a control portion that controls the supply of electric power to the plurality of heating elements. The power supply is controlled so that a first average temperature, which is an average value of control target temperatures of heating regions included in a first region located closer to one end side than a central heating region in a direction orthogonal to a conveying direction of a recording material, and a second average temperature, which is an average value of control target temperatures of heating regions included in a second region located closer to the other end side than the central heating region, are within a predetermined temperature range.

An example fuser includes a flexible fixing belt, a backup member to form a fixing nip with the fixing belt, a heater substrate for heating the fixing belt at the fixing nip and having a first surface comprising a heating element pattern, a common terminal and a driving power supply terminal for supplying power to the heating element pattern, and a second surface in contact with the fixing belt, and a temperature sensor sheet comprising a temperature sensor, a sensing terminal and an electric wire connecting the temperature sensor to the sensing terminal, wherein the temperature sensor sheet is in contact with the first surface of the heater substrate such that the sensing terminal and the electrical wire do not overlap the common terminal and the driving power supply terminal.

According to one embodiment, a heating device includes a fixing belt configured to be rotated and a pressure roller configured to abut against the fixing belt and be driven to cause the fixing belt to rotate. A heater is configured to heat the fixing belt. A motor is configured to drive the pressure roller to rotate. A current sensor is configured to measure a driving current of the motor. A controller is configured to stop the heater based on the measured driving current.

An image forming apparatus includes an image forming part, a fixing device, a fixing temperature sensor, a drive device, a printed sheet number counting part, a fixing voltage power supply, a controller, and an apparatus external temperature sensor. The controller can perform a cooling mode in which, when a number of continuous printed sheets at a reference speed exceeds an upper limit number, a number of printed sheets per unit time is gradually decreased to suppress an increase of an apparatus internal temperature. The controller sets the upper limit number based on a temperature difference between the fixing temperature detected by the fixing temperature sensor and the apparatus external temperature detected by the apparatus external temperature sensor.

A heater includes a substrate, a first heating element and a second heating element disposed on a first surface of the substrate, a temperature detection element, and a conductor. The temperature detection element is disposed on a second surface of the substrate opposite the first surface of the substrate. The conductor is disposed on the second surface and connected to the temperature detection element. The first heating element has a first distance from the temperature detection element in a lateral direction of the substrate orthogonal to a longitudinal direction of the substrate, and the second heating element has a second distance that is greater than the first distance from the temperature detection element in the lateral direction. As viewed in a thickness direction of the substrate orthogonal to the lateral direction and the longitudinal direction of the substrate, the conductor overlaps the first heating element and the second heating element.

A fixing apparatus includes a first rotary member, a nip forming unit including a heater and a holder member, a second rotary member, and a support member. The holder member includes a first surface configured to support the heater and provided on the nip portion side of the holder member in an orthogonal direction orthogonal to both of a longitudinal direction and a short direction, a second surface provided on a side of the holder member opposite to the first surface in the orthogonal direction and configured to abut a first abutting portion of the support member and abut a second abutting portion of the support member, and a rib portion provided to project from the second surface and extend in the short direction throughout at least a range in the short direction where the first surface is provided.