An image forming apparatus includes an image forming portion configured to form a developer image on a recording material, a fixing portion configured to heat-fix the developer image to the recording material, a first motor configured to drive the image forming portion, a second motor configured to drive the fixing portion, and a control portion configured to control the first motor and the second motor. The second motor is a stepping motor. The control portion allows the second motor to start rotation at a speed in a self-start region, temporarily stops the second motor at a timing at which the first motor is activated, then allows the second motor to restart rotation at a speed in the self-start region, and changes the speed of the second motor to a speed outside the self-start region before the recording material arrives at the fixing portion.

Provided is an image forming apparatus, in which a recording material is conveyed by a reverse portion rotated in a first direction at a first velocity which is faster than a conveyance velocity of the recording material in a fixing portion after a rear end portion of the recording material passes through the fixing portion, and then, the recording material is conveyed to a conveying portion by the reverse portion rotated in a second direction opposite to the first direction through a conveyance path at a second velocity which is faster than the conveyance velocity of the recording material in the fixing portion, and a conveyance velocity of the recording material is set to a third velocity which is slower than the second velocity at a predetermined timing before the rear end portion of the recording material reaches a curved portion of the conveyance path.

Provided is an image forming apparatus including a secondary transfer portion which transfers a toner image onto a recording material; a fixing device which fixes the toner image onto the recording material, and a belt conveying portion which adsorbs the recording material between the secondary transfer portion and the fixing device, and conveys the recording material, in which the belt conveying portion includes a first velocity at the time of receiving a front end portion of the recording material in a traveling direction from the secondary transfer portion, and a second velocity before a rear end portion of the recording material in the traveling direction leaves the secondary transfer portion at the time of delivering the front end portion of the recording material in the traveling direction to the fixing device, and the second velocity is faster than the first velocity.

A fixing unit includes a first heater, a first switch, a second heater, and a second switch. In an image forming mode, a controller controls the first switch and the second switch to keep a temperature of the fixing unit at a fixing temperature serving as a target temperature for fixing the image on the sheet. In a standby mode, the controller controls the first and second switches to keep the temperature of the fixing unit at a standby temperature, and controls the first and second switches such that a period in which a first current is supplied to the first heater and a period in which a second current is supplied to the second heater do not overlap.

A controller obtains a first duty cycle of a first current to be supplied to a first heater and a second duty cycle of a second current to be supplied to a second heater and controls the first switch and the second switch after the reduction control period, such that the temperature of a fixing unit maintains a target temperature for fixing the image by the fixing unit.

An image forming apparatus includes an exposure unit that reflects a laser beam emitted from a light source by a polygon mirror having a plurality of reflection surfaces to form a latent image on a photosensitive member, and a control unit that controls the image forming apparatus in a plurality of operation modes including a normal mode and a low speed mode having a slower process speed than the normal mode. The control unit controls the polygon mirror to use all of the plurality of reflection surfaces to reflect the laser beam when in the normal mode. When in the low speed mode, the control unit makes the process speed faster than 0.5 times that of the normal mode, rotates the polygon mirror faster than in the normal mode, and controls the polygon mirror to use only some of the plurality of reflection surfaces to reflect the laser beam.

An image forming apparatus includes a fixing device and a drive transmission mechanism. The fixing device fixes an image on a sheet by application of heat and pressure. The drive transmission mechanism changes a conveying speed of the sheet in the fixing device between an image forming mode and a lamination mode. The conveying speed of the sheet in the fixing device in the lamination mode is lower than the conveying speed of the sheet in the fixing device in the image forming mode.

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 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.