The present invention is characterized in that a 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 a recording material, and a difference between the heating amount with respect to the region in which an image is formed and the heating amount with respect to the region in which an image is not formed differs depending on a type of the recording material.

An image forming apparatus includes a heating rotary member, a pressure rotary member, a nip portion formed by the rotary members, a temperature adjustment control section controlling a temperature of the heating rotary member to a target temperature, a cleaning web removing toner adhering to the heating rotary member, and a controller selectively executing one of a cleaning mode and a non-cleaning mode. A first basis weight and a second basis weight greater than the first predetermined basis weight are set, in a job that mixedly uses recording media with the first and second basis weights. When the controller executes the non-cleaning mode, the temperature adjustment control section sets a target temperature of a recording medium with a basis weight less than or equal to the first basis weight to a temperature lower than a target temperature of the recording medium in the cleaning mode.

An image forming apparatus is disclosed. A fixing device includes a heating rotary member and a pressing rotary member. The fixing device further includes an acquisition means that acquires information about a printing medium for a predetermined number of sheets beforehand, and a temperature control means that controls a temperature of the heating rotary member based on the information about a basis weight acquired by the acquisition means. A job in which different basis weights are mixed is a mixed job. In a case where the mixed job is executed and the temperature of the heating rotary member is changed while the mixed job is executed, a change amount of the temperature of the heating rotary member is reduced based on the information about the basis weight of the printing medium acquired by the acquisition means.

An example device includes: a print engine including a fuser; an ambient temperature sensor; a memory storing a plurality of curves that relate, for given respective ambient temperatures, respective time periods for the fuser to heat to a fusing temperature, to respective factors associated with cooling of the fuser; and a processor The processor is to: detect a current ambient temperature using the ambient temperature sensor; select a curve, from the plurality of curves, using the current ambient temperature; determine a current factor associated with cooling of the fuser; and control the fuser to heat to the fusing temperature based on a respective time period determined from the curve and the current factor associated with cooling of the fuser.

According to an embodiment, an image forming apparatus measures a temperature of a pressing member and controls heat generation of a heater such that the measured temperature approaches a control temperature. Further, the image forming apparatus sets, before starting image formation of one job including image formation, one candidate temperature of a plurality of predetermined candidate temperatures different from each other as the control temperature on the basis of the number of sheets to be used and a sheet size to be used in the image formation of the one job.

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 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 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 fixing device includes a tubular body in a tubular shape that forms a nip with a pressurizing member. The heater, disposed inside the tubular body, faces a part of the tubular body in a circumferential direction. The heat equalizing member is disposed on an opposite side of a side where the heater faces the tubular body. The heat equalizing member transfers heat from a place having a high temperature to a place having a low temperature in a second direction along an axial direction of the tubular body. The heat conductive member, disposed between the heater and the heat equalizing member, can conduct the heat in each of the second direction and a first direction in which the heater and the heat equalizing member face each other. A side portion of the heat conductive member in the second direction is divided into three or more portions.

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.