Selecting one conveyance mode from a plurality of conveyance modes includes a first selection process of selecting the one conveyance mode based on a detection temperature of a temperature sensor from a first time point at which rotation of a fixing rotator is started to a second time point at which a particular period elapses from the first time point. The first selection process includes: determining whether an initial temperature is higher than or equal to a first temperature, the initial temperature being a detection temperature of the temperature sensor when a print instruction is received; in response to determining that the initial temperature is lower than the first temperature, setting the particular period to a first period; and in response to determining that the initial temperature is higher than or equal to the first temperature, setting the particular period to a second period longer than the first period.

An image forming apparatus is configured to execute image forming processing of forming an image on a sheet. The apparatus includes a photosensitive drum, a fixing device including a heater and a roller, a main motor configured to generate a driving force, a driving mechanism having a connected state in which the driving force is transmittable to both the roller and the photosensitive drum, and a disconnected state in which the driving force is transmittable to the roller but is not transmitted to the photosensitive drum, a temperature sensor configured to detect a temperature of the fixing device, and a controller. In a case where the image forming processing is started, the controller sets the driving mechanism into the disconnected state, rotates the main motor at a preheating speed, and executes preheating processing in which the fixing device is heated by the heater.

An image formation apparatus according to an embodiment includes a fixation device and a controller. The fixation device includes: a fixation member that includes a first region and a second region located closer to a center in a longitudinal direction of the fixation member than the first region; a pressurizing member that forms a nip portion between the fixation member and the pressurizing member; first and second heat generating portions that heat the first and second regions, respectively; a first sensor that detects a first temperature of one of the pressurizing member and the fixation member at a position corresponding to the first heat generating portion; and a second sensor that detects a second temperature of the one at a position corresponding to the second heat generating portion. The controller controls a drive speed of the pressurizing member or the fixation member based on the first and second temperatures.

An image forming apparatus includes: a transferer that transfers a toner image on an image carrier formed by an image former onto a paper sheet; a fixer that heats and thereby fixes the toner image on the paper sheet; a read image acquisitor that acquires read image data of the paper sheet on a downstream side of the fixer in a conveyance direction, the read image data being generated by a reader that reads an image of the paper sheet; and a hardware processor that: controls a conveyance speed of the paper sheet in the transferer and/or the fixer, and changes or updates the conveyance speed based on an image of the acquired read image data.

In general, a fixing device according to an embodiment includes an endless belt, a pressure element, a heating member, an adjustment mechanism, and a controller. The pressure element conveys a sheet while interposing the sheet under pressure between the same and the endless belt. The heating member is provided on the inner side of the endless belt and has a heat generating element for heating the endless belt. The adjustment mechanism moves at least one of the heating member and the pressure element in such a direction as to bring the one closer to or away from the other, to adjust the nip width which is the length of an interposing and pressurizing region in a sheet conveyance direction, the interposing and pressurizing region being formed by the heating member and the pressure element to interpose the endless belt under pressure. The controller controls the adjustment mechanism so that A>B≧N is satisfied, where A is the nip width during a fixing process in which the sheet is heated to fix a color material onto the sheet, B is the nip width during temperature raising of the heating member to be conducted before the fixing process, and N is the length of the heat generating element in the sheet conveyance direction.

A fixing device includes an endless belt, a drive rotator, a driven rotator, a rotation detector, and circuitry. The drive rotator contacts and rotates the endless belt. The driven rotator contacts an inner circumferential surface of the endless belt. The rotation detector detects a rotational speed of the driven rotator. The circuitry is operatively connected to the rotation detector to control a rotational speed of the drive rotator based on the rotational speed of the driven rotator detected by the rotational detector. The circuitry changes the rotational speed of the drive rotator when a recording medium bearing a toner image is not conveyed over the endless belt.

An image forming apparatus includes an image forming device, a fixing device including a first rotary member of which a surface layer containing a fluororesin is brought into contact with a sheet surface having an unfixed toner image formed by the image forming device, and a controller. In a case that image formation processing for continuously forming a toner image on a plurality of predetermined sheets is executed, the controller can control conveyance of a sheet so that a portion of the surface layer of the first rotary member which is brought into contact with a trailing edge of a preceding sheet is brought into contact with a margin area on a leading edge side on a next sheet.

An image forming apparatus include a transport unit, a tension adjusting unit, a transfer unit, a fixing unit, and a controller. The transport unit transports continuous paper. The tension adjusting unit adjusts tension of the continuous paper being transported by the transport unit. The transfer unit transfers an image to the continuous paper transported by the transport unit. The fixing unit fixes the image transferred by the transfer unit onto the continuous paper. The controller controls, in a case where the fixing unit is driven in a state in which the fixing unit is separated from the continuous paper and a difference between a transport speed of the transport unit and a fixing speed of the fixing unit has reached a predetermined range, the fixing unit to be in press-contact with the continuous paper.

An image forming apparatus includes a control unit configured to execute a sheet discharge mode. If a case where a distance between the leading edge and the nip portion is a first distance is a first case, and a case where a distance between the leading edge of the sheet and the nip portion is a second distance shorter than the first distance and the temperature detected by the temperature detection unit is the same as that in the first case is a second case, the control unit is configured to set a conveyance speed of the sheet in discharging the sheet toward the nip portion in the second case to be slower than that in the first case, in the sheet discharge mode.

An image forming apparatus includes a forming part that forms an image on a ribbon-like medium that is being transported; and a fixing part disposed downstream of the forming part in a medium transport direction, the fixing part including multiple fixing members, which are arranged in the transport direction and fix the image to the medium by applying heat and pressure to the medium. An upstream-downstream tension difference, in the medium transport direction, of the fixing member located on the most upstream side in the transport direction is greater than those of the other fixing members in the medium transport direction.