An image forming apparatus includes a plurality of sheet storage receptacles configured to store a sheet. The image forming apparatus also includes a fixing device having a heating belt and a pressure roller configured to heat and fix toner on the sheet conveyed from one of the plurality of sheet storage receptacles. The image forming apparatus also includes a processor and a memory configured to store temperature information associated with each sheet storage receptacle and related to temperature control of the fixing device, acquire type information of a sheet to be printed, in response to a predetermined condition, specify the sheet storage receptacle storing the sheet to be printed, and perform a first heating control that controls a temperature of the fixing device based on the stored temperature information associated with the specified sheet storage receptacle.

An image forming apparatus includes: an acquiring portion configured to acquire image information and operation information of the image forming apparatus; an image forming portion configured to form a toner image on a recording material; a fixing portion configured to fix the toner image to the recording material by heating the recording material on which the toner image is formed; and a control portion configured to, when the acquiring portion acquires image information corresponding to a first page and fails to acquire image information corresponding to a second page following the first page, set a temperature of the fixing portion for fixing the first page as a first temperature based on the image information corresponding to the first page and the operation information, and set the temperature of the fixing portion for fixing the second page as a second temperature based on the operation information.

An image forming apparatus, including: an image forming portion that forms an image on a recording material based on image data; a fixing portion that includes a heater having a plurality of heat generating members arranged in a direction perpendicular to a conveying direction of a recording material, and that fixes the image to the recording material using heat of the heater; a storage portion that stores history information on the recording material when image forming operation is performed in which the image forming portion forms the image and the fixing portion fixes the image, a control portion that sets power to be supplied to the heat generating members based on the history information before a type of the recording material on which the image is formed or content of the image data of the image to be formed on the recording material is determined.

An image forming apparatus includes a controller configured to identify a selected sheet size setting as defined by a dimension in the width direction and a dimension in the conveyance direction, set a cooling threshold at a first threshold if the selected sheet size setting is a first size having a dimension in the width direction larger than a predetermined dimension, and a dimension in the conveyance direction larger than the dimension in the width direction, and set the cooling threshold at a second threshold lower than the first threshold if the selected sheet size setting is a second size having a dimension in the width direction that is the same as the dimension in the width direction of the first size, and a dimension in the conveyance direction smaller than the dimension in the width direction.

A fixing device includes a heater, a fixing rotator, a first temperature sensor, a second temperature sensor, a contact rotator, and circuitry. The fixing rotator has an outer circumferential surface having a first area and a second area. The first area contacts both a first sheet and a second sheet having a width narrower than the width of the first sheet. The second area contacts the first sheet but does not contact the second sheet. The first temperature sensor detects a first temperature of the first area. The second temperature sensor detects a second temperature of the second area. The contact rotator contacts both the first area and the second area and rotates at the one of at least two relative velocities with respect to the fixing rotator. The circuitry sets one of the at least two relative velocities based on the first temperature and the second temperature.

An image forming apparatus includes a plurality of sheet storage receptacles configured to store a sheet. The image forming apparatus also includes a fixing device having a heating belt and a pressure roller configured to heat and fix toner on the sheet conveyed from one of the plurality of sheet storage receptacles. The image forming apparatus also includes a processor and a memory configured to store temperature information associated with each sheet storage receptacle and related to temperature control of the fixing device, acquire type information of a sheet to be printed, in response to a predetermined condition, specify the sheet storage receptacle storing the sheet to be printed, and perform a first heating control that controls a temperature of the fixing device based on the stored temperature information associated with the specified sheet storage receptacle.

A fixing apparatus to fix a toner image formed on a recording material to the recording material includes a rotatable member having a heat generation layer, a power supply circuit, and a control unit. The power supply circuit supplies electrical power to the rotatable member. The control unit controls supply of electrical power to the rotatable member and detects a change rate of electrical resistance of the heat generation layer. The heat generation layer generates heat by the electrical power supplied to the rotatable member, and the toner image on the recording material is fixed to the recording material by the heat from the heat generation layer. If the change rate of the electrical resistance to the supplied electrical power is higher than a predetermined threshold, the control unit stops the supply of electrical power to the rotatable member.

A fixing device includes a heater, a fixing rotator, a first temperature sensor, a second temperature sensor, a contact rotator, and circuitry. The fixing rotator has an outer circumferential surface having a first area and a second area. The first area contacts both a first sheet and a second sheet having a width narrower than the width of the first sheet. The second area contacts the first sheet but does not contact the second sheet. The first temperature sensor detects a first temperature of the first area. The second temperature sensor detects a second temperature of the second area. The contact rotator contacts both the first area and the second area and rotates at the one of at least two relative velocities with respect to the fixing rotator. The circuitry sets one of the at least two relative velocities based on the first temperature and the second temperature.

An image forming apparatus, including: an image forming portion that forms an image on a recording material based on image data; a fixing portion that includes a heater having a plurality of heat generating members arranged in a direction perpendicular to a conveying direction of a recording material, and that fixes the image to the recording material using heat of the heater; a storage portion that stores history information on the recording material when image forming operation is performed in which the image forming portion forms the image and the fixing portion fixes the image, a control portion that sets power to be supplied to the heat generating members based on the history information before a type of the recording material on which the image is formed or content of the image data of the image to be formed on the recording material is determined.

An image forming apparatus includes an image former, a fuser, a first sensor, and a processor. The image former is configured to form an image on a recording medium. The fuser is configured to fix the image on the recording medium. The first sensor is configured to detect a temperature of the fuser. The processor is configured to cause the recording medium to be supplied to the fuser after warming up the fuser to a warm up temperature. The processor is also configured to supply power to the fuser after causing the recording medium to be supplied to the fuser, an amount of the supplied power being based on the temperature detected before starting the warming up.