An image forming apparatus includes a heat roller comprising a heater and configured to generate heat to fix a toner image on a print medium, a system controller configured to transmit, when printing is performed on a print medium, a control signal that indicates when power is to be supplied to the heater, and a heater control circuit configured to control amount of power supplied to the heater according to the control signal, a target temperature of the heater, and a current temperature of the heater. When printing is to be continuously performed on a plurality of print media, the system controller transmits the control signal to the heater control circuit a first predetermined time before start of printing.

A fixing apparatus includes a plurality of heat generating elements for heating a developer image formed on a recording medium corresponding to a plurality of heating regions. A first target temperature of the heat generating elements is set based on a developer amount per unit area of the developer image in each of the heating regions, and the temperature of the heat generating elements is controlled to the first target temperature. If a difference between the first target temperatures for two adjacent heating regions is outside of a predetermined range, the first target temperature for one of the two adjacent heating regions is corrected to a second target temperature, which is greater than the first target temperature, so that the difference between the first target temperatures for the two adjacent heating regions is within the predetermined range.

An image forming apparatus includes a heat roller comprising a heater and configured to generate heat to fix a toner image on a print medium, a system controller configured to transmit, when printing is performed on a print medium, a control signal that indicates when power is to be supplied to the heater, and a heater control circuit configured to control amount of power supplied to the heater according to the control signal, a target temperature of the heater, and a current temperature of the heater. When printing is to be continuously performed on a plurality of print media, the system controller transmits the control signal to the heater control circuit a first predetermined time before start of printing.

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 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 heating apparatus has a heater to heat an image formed on a recording material. The heater has a plurality of heat generating elements. A control portion controls electrical power supplied to the plurality of heat generating elements. The control portion respectively sets a heating amount with respect to a region in which an image is formed and a heating amount with respect to a region in which an image is not formed in a single sheet of the recording material. The control portion is further configured to at least set the heating amount with respect to the region in which the image is not formed when the recording material is heavy paper to become less than the heating amount with respect to the region in which the image is not formed when the recording material is plain paper.

A controller is configured to control a drive unit and a heating element to execute a first mode and a second mode. The first mode is a mode in which the sheet is conveyed through a predetermined conveyance section in a duplex image formation by taking a first time length. The second mode is a mode in which the sheet is conveyed through the conveyance section in the duplex image formation by taking a second time length longer than the first time length. In the second mode, the controller is configured to execute a temperature decrease processing and thereafter execute a temperature increase processing in a period in which the sheet is conveyed through the conveyance section.

An image forming apparatus includes: an image forming device that forms an image on a sheet; a fixing device that includes a heating member and heats the sheet on which the image is formed by the image forming device, to fix the image on the sheet; a detector that detects a temperature in the fixing device; and a hardware processor that performs PID control of a turn-on rate of the heating member according to a deviation between a detected temperature by the detector and a target temperature, the PID control being in accordance with an expression including at least a proportional term or an integral term and further including a constant term of a value corresponding to an operation condition of the apparatus, wherein the hardware processor calculates an average turn-on rate of the heating member during execution of the operation, and updates the value of the constant term.

An air blowing cooling mechanism includes a duct, a fan, a first shutter member, a second shutter member, a first drive transmitting portion for transmitting a driving force to the second shutter member, and a second drive transmitting portion for transmitting the driving force from the second shutter member to the first shutter member. The second shutter member is supported by the duct so as to be slidable relative to the duct. The first shutter member is supported by the second shutter member so as to be slidable relative to the second shutter member. The second shutter member includes a slidable portion slidable relative to the first shutter member when said first shutter member slides.

A heating device includes a heater including a heat generator that generates heat as the heat generator is supplied with power. A feeding member contacts the heater and feeds the power to the heat generator. An endless belt rotates and is heated by the heater. A driving roller contacts an outer circumferential surface of the endless belt. A driving force transmitter is disposed at one lateral end of the driving roller in an axial direction of the driving roller. The driving force transmitter transmits a driving force that drives and rotates the driving roller. The feeding member is made of a corson copper alloy and is disposed in a non-driving side defined by a center of the heat generator in a longitudinal direction of the heater. The non-driving side is opposite a driving side in the longitudinal direction of the heater, where the driving force transmitter is disposed.