An image forming apparatus includes a reverse roller pair configured to reverse a conveyance direction of a recording medium between a first direction and a second direction, a first conveyance roller pair configured to convey the recording medium in the first direction, and a second conveyance roller pair configured to convey the recording medium in the second direction. A first distance is between the first conveyance roller pair and a reversal position in which a trailing edge of the recording medium is located when the conveyance direction is reversed. A second distance is between the reversal position and the second conveyance roller pair. An absolute value of a difference between the first distance and the second distance is an integer multiple of a circumferential length of a drive roller of the reverse roller pair or within a predetermined range from the integer multiple.

An image forming apparatus includes a reverse roller pair including a drive roller and a driven roller by which a recording medium is nipped and conveyed reversibly, a motor configured to rotate the drive roller reversibly, a conveyance roller pair, a detection unit configured to detect the recording medium conveyed by the conveyance roller pair, and a controller configured to control the motor, in a case in which the recording medium is detected by the detection unit, to cause the drive roller to rotate in a first rotation direction by a first rotation amount, thereafter to cause the drive motor to rotate in a second rotation direction by a second rotation amount. A difference between the first rotation amount and the second rotation amount is set to an integer multiple of a predetermined rotation amount of the motor, the predetermined rotation amount making the drive roller one rotation.

A controller is configured to control a print engine and a conveyor to form an image on both sides of a sheet. The controller is configured to: in a case where images to be formed on both sides of each of an Nth (N is a positive integer) sheet, an (N+1)th sheet, and an (N+2)th sheet are all monochrome image or all color image, convey the (N+2)th sheet to the print engine and form an image before forming an image on both sides of the (N+1)th sheet; and in a case where the images to be formed on both sides of each of the Nth sheet, the (N+1)th sheet, and the (N+2)th sheet are a mixture of the monochrome image and the color image, convey the (N+2)th sheet to the print engine and form an image after forming an image on both sides of the (N+1)th sheet.

An image forming apparatus for forming an image on a sheet, includes an image forming unit configured to form the image on the sheet, a double-sided conveyance path through which the sheet with the image formed on a first surface passes before the image forming unit forms an image on a second surface opposite to the first surface, a guide member having a contact portion configured to contact one end of the sheet in the width direction of the sheet, the guide member being provided on the double-sided conveyance path, and a reversing roller pair forwardly and reversely rotatable, configured to convey the sheet to the double-sided conveyance path during a reverse rotation, the reversing roller pair having a drive shaft, and a first roller and a second roller coaxially disposed on the shaft, rotatable with the shaft, wherein the second roller is disposed at a position more away from the contact portion than the first roller in the axial direction of the shaft, the second roller having a larger outer diameter than the first roller.

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.

A drive transmission device includes a drive train including a plurality of drive transmitters, and a container. The plurality of drive transmitters of the drive train transmit a driving force of a drive source to a rotator rotatable around a shaft and a swing member rotatable around a shaft different from the shaft of the rotator. The container contains the drive train.

In order to miniaturize an image forming system, the present invention provides an image forming system which is provided with a sheet feed apparatus including a transport roller pair capable of transporting a sheet in a sheet transport direction S, and an image forming apparatus including an image forming section capable of forming an image on the sheet acquired from the sheet feed apparatus, including a switch member disposed on the downstream side of the transport roller pair in the sheet transport direction to be switched between a first position for guiding the sheet transported by the transport roller pair to the image forming apparatus, and a second position for guiding the sheet transported by the transport roller pair downward, and a storage tray disposed below the switch member predetermined space apart to be able to store the sheet guided to below the switch member positioned in the second position.

An image forming apparatus includes an image forming portion, a reversing portion configured to reverse the sheet received through a first feeding passage by feeding the sheet in a first direction and then in a second direction opposite to the first direction, a sheet feeding portion provided in a second feeding passage branching from the first feeding passage on a side upstream of the reversing portion with respect to the first direction, a first guiding surface forming the second feeding passage for guiding a first surface of the sheet fed by the feeding portion, and a second guiding surface for guiding a second surface, opposite from the first surface, of the sheet fed from the reversing portion in the second direction. The second guiding surface is movable with movement of the first guiding surface for opening the second feeding passage.

An image forming apparatus includes an image forming unit to form an image on a sheet, a conveyance guide unit, and a conveyance unit. The conveyance guide unit conveys the sheet on which the image is to be formed by the image forming unit. The conveyance unit conveys the sheet toward a first conveyance guide unit. The conveyance guide unit includes an urging member, a rotary member to be urged by the urging member and to rotate while abutting the sheet, a holding unit holding the urging member and the rotary member, and the first conveyance guide unit that is detachably attached to the holding unit to guide the sheet. The first conveyance guide unit includes a pressed portion, and the pressed portion is to be pressed by the sheet conveyed by the conveyance unit and has strength less than strength of the holding unit.

An image forming apparatus includes a single fan, a first air outlet port disposed so as to supply air sent from the fan to an image surface of the sheet, a second air outlet port disposed so as to supply the air sent from the fan to a surface opposite to the image surface of the sheet, and a control unit configured to control the fan. The control unit includes a first mode of controlling a rotational speed of the fan at a first rotational speed in a case where the sheet is not present in a position facing the first air outlet port and control the rotational speed of the fan at a second rotational speed lower than the first rotational speed in a case where the sheet is present in the position facing the first air outlet port.