An image forming apparatus includes an image forming unit configured to form an image on a sheet, a stacking portion on which the sheet having the image formed thereon is to be stacked, a first roller capable of forward and reverse rotations, a second roller capable of rotating with the first roller when the first roller makes a forward rotation, a third roller capable of rotating with the first roller when the first roller makes a reverse rotation and then the forward rotation, a regulation portion movable between a regulation position where entering of the sheet into a nip portion between the first and second rollers is prevented, and an allowing position where discharge of the sheet is allowed, and a movement unit configured to cause the regulation portion to be placed in the allowing position during forward rotation, and to be placed in the regulation position during reverse rotation.

A transmission unit transmits driving force to be supplied from a motor to a roller pair. A switching unit acts on the transmission unit to switch a rotation direction of the roller pair by the driving force between a normal rotation and a reverse rotation. A control unit controls a rotation speed of the motor to convey the sheet at a second conveyance speed in a part of a first time period. The second conveyance speed is lower than a first conveyance speed. The first conveyance speed is a conveyance speed when the sheet is conveyed in the image forming unit. In the first time period the sheet having the image formed on the first surface is conveyed in a first direction. In a second time period the sheet is conveyed in a second direction.

A heating device includes a heating rotator, a pressing rotator, and a housing. The heating rotator extends in a longitudinal direction and is configured to heat a sheet. The pressing rotator extends in a longitudinal direction and is configured to press against the heating rotator to form a nip with the heating rotator. The housing houses the heating rotator and the pressing rotator. The housing includes a pair of openings and shutters. The pair of openings face both end portions of the heating rotator in the longitudinal direction of the heating rotator. The shutters are configured to rotate about an axis extending in the longitudinal direction of the heating rotator to open and close the pair of openings.

An image forming apparatus, having a photosensitive drum, an intermediate transfer belt located at a lower position with respect to the photosensitive drum to contact the photosensitive drum, a secondary transfer roller contacting the intermediate transfer belt, a first sheet tray located at a lower position with respect to the intermediate transfer belt to store a sheet, and a sheet guide to guide the sheet stored in the first sheet tray to a position between the intermediate transfer belt and the secondary transfer roller, is provided. The sheet guide is located between the intermediate transfer belt and the first sheet tray with regard to a vertical direction and has a curved section. A contact area between the secondary transfer roller and the intermediate transfer belt is located at a lower position with respect to an upper end portion of the curved section.

An image forming apparatus suppresses the occurrence of dew condensation in a post-processing operation when the sheet is jammed. When information indicating that a sheet is jammed is received, if the sheet detecting sensor detects the sheet on a switching member, a controller executes a conveying action to drive the sheet conveying portion until an upstream edge of the sheet in the sheet conveyance direction passes through the switching member and then stops the sheet conveying portion.

An image forming apparatus is configured such that in a case where images are to be formed on a first surface of a preceding sheet, on a first surface of a succeeding sheet fed to the first conveyance path succeeding to the preceding sheet and on a second surface of the preceding sheet, a first conveyance member is stopped without reversing the preceding sheet to a second conveyance path in a case where the image has been formed on the first surface of the preceding sheet and permission of preparing the image to be formed on the first surface of the succeeding sheet is not issued yet. The first conveyance member restarts conveyance of the preceding sheet to the second conveyance path based on timing when an image forming unit starts preparing the image to be formed on the first surface of the succeeding sheet.

An image forming apparatus with a duplex printing function may include a closeable and openable portion. In one example, the portion may correspond to a cover of the image forming apparatus. The cover may include guiding portions configured to define a return path for duplex printing. In another example, the portion may correspond to a document reading unit including an outer casing. A portion of the outer casing may be configured to guide a recording sheet that is conveyed out of a housing of the image forming apparatus by a switchback roller. In one example, the switchback roller may convey a recording sheet to a position above an upper surface of the outer casing.

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.

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.

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.