An image forming apparatus includes an image forming portion, a sheet feeding portion, a first guiding member, a second guiding member, a driving portion, a detecting portion, and a controller. When a leading end of a sheet is detected by the detecting portion, in a case that information on a thickness of the sheet fed by the sheet feeding portion is a first thickness, the controller controls the driving portion so that a distance in a sheet feeding passage with respect to a thickness direction is a first distance, and in a case that the information on the thickness of the sheet fed by the sheet feeding portion is a second thickness thinner than the first thickness, the controller controls the driving portion so that the distance in the sheet feeding passage with respect to the thickness direction is a second distance shorter than the first distance.

An image forming apparatus includes an image bearing member, an image forming portion, an endless belt, a plurality of stretching rollers including an inner roller, an outer roller, a position changing mechanism capable of changing a position of the inner roller to a first position and a second position positioned downstream of the first position with respect to a rotational direction of the endless belt, a feeding member, a feeding member driving portion, and a controller. A feeding start timing of a recording material by the feeding member depends on the position of the inner roller during transfer of a toner image onto the recording material.

A sheet feeding device includes a sheet feeding roller, a following roller, a rotational speed detection part, and a control part. The rotational speed detection part is configured to detect a rotational speed of the following roller. The control part is configured to accelerate a rotation of the sheet feeding roller and to adjust a sheet interval. The control part obtains a rotational rate of the following roller to the sheet feeding roller based on the rotational speed of the following roller, obtains an actual linear velocity of the sheet based on the rotational rate of the following roller and a theoretical linear velocity of the sheet after accelerating the rotation of the sheet feeding roller, and then adjusts the sheet interval based on the actual linear velocity of the sheet.

An image forming apparatus includes: an inverting unit that inverts a sheet when an image forming process for forming images on both sides of the sheet is performed; an image forming unit that forms an image on a second side of the sheet based on first side image data and forms an image on a third side of the sheet based on second side image data; a controller that starts the image forming process upon receiving print data to be printed on specific paper, and inverts a sheet fed from a sheet feeding unit once or more; and a converting unit that, when the sheet fed from the sheet feeding unit is the specific paper, converts the first side print data which is received to be printed on the specific paper into N-th side image data where N≥2 and transfers the N-th side image data to the image forming unit.

An image forming apparatus includes a feeding unit, a detection unit provided downstream of the feeding unit, a measurement unit that measures a measured time from the start of conveyance of a recording material to the detection of the recording material, and a determination unit that performs renewal determination for determining whether the feeding unit has been replaced with a new feeding unit. Thus, replacement of the feeding unit with a new feeding unit can automatically be detected.

An image forming apparatus fixes a toner image onto a sheet by a fixer, and includes: a re-feeding path that normally conveys the sheet having passed through the fixer and guides the sheet toward the fixer; and a hardware processor that switches between first control to discharge the sheet having passed through the fixer toward a discharge destination and second control to re-feed the sheet having passed through the fixer to the fixer through the re-feeding path, depending on a type of an image which is a source of formation of the toner image.

An image forming apparatus includes an image formation unit configured to form an image on a sheet at a formation position; a circulatory conveyance path for conveying the sheet with the image formed at the formation position on a first side thereof to the formation position again; a reading unit configured to read the first side of the sheet conveyed through the circulatory conveyance path and output image information; and a conveyance control unit configured to convey the sheet in one conveyance mode out of a plurality of conveyance modes when the reading unit reads the first side of the sheet. A range, in a conveyance direction, of the sheet that can be read by the reading unit while a conveyance speed of the sheet is constant is different for each of the plurality of conveyance modes.

After outputting a first start signal for causing an image forming unit to start formation of an image for a first side of an i-th sheet, a controller causes a feeding member to start feeding of the i-th sheet, and determines whether or not the i-th sheet has already been detected by a detector. In a case where the i-th sheet has been detected before a predetermined time has elapsed, the controller outputs a second start signal for causing the image forming unit to start formation of an image for second side of an (i−1)th sheet. In a case where the i-th sheet has not been detected before the predetermined time has elapsed, the controller outputs the second start signal after the i-th sheet is detected.

An image forming apparatus includes an image forming portion, an oblique movement correcting portion including a first registration roller pair and a first moving portion, a reversing portion, and a re-feeding portion. The reversing portion includes a reversing roller pair and a second moving portion. The re-feeding portion includes a second registration roller pair. When an image is formed on a second surface of a sheet opposite from a first surface of the sheet, a side end position of the sheet is corrected by the second moving portion and oblique movement of the sheet is corrected, and then the side end position of the sheet is corrected again by the first moving means and the sheet is fed to the image forming portion.

An image forming apparatus includes a first processor configured to control a transporter that transports a sheet and a first image forming section that forms an image on the sheet transported by the transporter, and a second processor configured to control a second image forming section that forms an image on the sheet transported by the transporter. The first processor and the second processor are contained in a single housing. When the first processor receives an image formation command from outside the housing and determines to perform an image forming process at the first image forming section, the first processor is configured to perform transport preparation for transporting the sheet at the transporter and receive, from the second processor, a completion notification corresponding to a preparation command, for performing image formation preparation in the second image forming section, transmitted to the second processor via an inside of the housing, and subsequently cause the transporter to transport the sheet and the first image forming section to form the image. If the first processor ascertains that an independent process involving not forming the image at the first image forming section but forming the image at the second image forming section is to be performed, the first processor is configured to perform the transport preparation before receiving the completion notification, and cause the transporter to transport the sheet after receiving the completion notification.