An image forming apparatus includes a toner image forming unit, a fuser including a heater, a temperature sensor that detects a temperature of the fuser, and a controller. The controller exercises a standby control that includes repeating a control cycle, measuring a temperature fluctuation period that is a time period from start of energizing the heater to an end of the control cycle, and setting an energization amount for a next control cycle, based on the measured temperature fluctuation period. The control cycle includes energizing the heater with an energization amount during a preset heating period when the detection temperature has dropped to a temperature below the target standby temperature, and waiting until the detection temperature drops to the target standby temperature in a case where the detection temperature has risen to a temperature equal to or above the target standby temperature after the preset heating period has elapsed.

A transfer device includes a transfer drum that rotates in conjunction with a fixing roller, a transfer belt that transfers an image onto a medium while rotating along with the transfer drum in a state where the medium is nipped between the transfer belt and the transfer drum, a pressing member that is disposed in a space enclosed by the transfer belt, and a switching unit that moves the pressing member and switches between a pressed state in which the transfer belt is pressed against the transfer drum and a separated state in which the transfer belt is separated from the transfer drum.

An image forming apparatus includes: sheet feeding trays; an image forming part that includes a fixing part and forms an image on a sheet fed from each of the sheet feeding trays based on a print job; and an acquisition part that acquires information indicating “presence” or “absence” of a possible carrier having a possibility of virus infection in a region where an apparatus main body is installed; and a hardware processor that is able to select an operation mode of the print job from a normal mode and a virus removal mode, and sets an operation mode of the print job to the virus removal mode, wherein in the virus removal mode, a fixing temperature of the fixing part is set to a predetermined temperature, and a heating time for the sheet in the fixing part is made longer than a heating time in the normal mode.

A fixing device includes a fixing rotator over which a recording medium bearing an image is conveyed. A first heater heats the fixing rotator and generates heat evenly in a maximum conveyance span where the recording medium having a maximum width in a width direction of the recording medium is conveyed. The maximum width is available for the fixing rotator. A second heater heats the fixing rotator and generates heat in the maximum conveyance span. The second heater includes a first portion that generates heat in a first heat generation amount and a second portion that generates heat in a second heat generation amount that is greater than the first heat generation amount of the first portion.

In an image forming apparatus, upon receipt of a printing instruction, a controller starts rotation of a heating member, starts rotation of a photoconductor drum when a standby time has elapsed from a time of the start of the rotation of the heating member, starts conveyance of a sheet after the start of the rotation of the photoconductor drum, and forms a toner image on the sheet after the start of the conveyance of the sheet. The controller is configured to be operated in one of selectable modes including a multicolor mode in which a toner image is formed using both of toner of a first color and a second color and a monochrome mode in which a toner image is formed using toner of the second color only. The standby time adopted in the monochrome mode is longer than the standby time adopted in the multicolor mode.

An image forming apparatus, temperature control method, and temperature control device are provided. The apparatus includes the device, which acquires a first temperature difference between a temperature estimation value of a fixer, which is obtained by simulating a member temperature of a temperature control target serving as a heat capacitor-resistor circuit at an initial stage of operation of the fixer, and a detected temperature detected by a temperature sensor, and acquires a second temperature difference between a temperature estimation value of the fixer, which is obtained during an operation after the first temperature difference is acquired, and a detected temperature. The device calculates a difference between the first temperature difference and the second temperature difference, determines that the detected temperature is abnormal in response to the difference being equal to or greater than a threshold value, and performs temperature control for correcting a target temperature of the member temperature.

An image forming apparatus including a print engine, a power supply device, a plurality of temperature sensors, and a processor. The print engine including a fuser. The power supply device to selectively provide power to the fuser. The plurality of temperature sensors including a first temperature sensor and a second temperature sensor to sense temperature of the fuser. The processor to control power supplied to the fuser based on a value measured by at least one temperature sensor from among the plurality of temperature sensors. The processor is to identify whether the at least one temperature sensor of the plurality of temperature sensors has an abnormality based on a first measured temperature value and a second measured temperature value of the plurality of temperature sensors.

An image forming apparatus includes a plurality of heaters, a switch portion, and first and second supply lines. The heaters heat a toner image. The switch portion is connected to an alternating-current power source, and opens and closes in a manner interlocked with the opening and closing of a cover. The first supply line connects the respective one ends of the heaters to the switch portion. The second supply line connects the respective other ends of the heaters to the switch portion. The second supply line has a branch portion. The respective other ends of the heaters are each connected to one of branch lines which are electric wires that branch off from the branch portion. The switch portion is disposed between the branch portion and the alternating-current power source.

In one embodiment, an image forming apparatus includes a fixing device with a heating element to heat a sheet. A controller is configured to control electric power supplied to the heating element based on a prior use metric. The controller reduces the electric power supplied to the heating element during a startup period if an electric power level supplied from a power supply is equal to or greater than a threshold value and the prior use metric is equal to or greater than a reference value.

A temperature control device according to one embodiment includes a temperature estimation unit, a comparison unit, and an energization control unit. The temperature estimation unit estimates a temperature of an object based on energization of elements related to temperature control of the object. The comparison unit compares a difference between a detected temperature of the object and an estimated temperature of the object. If the difference exceeds a reference value, the energization control unit stops energizing the elements related to the temperature control of the object.