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 an image forming unit, a paper loading base on which manual-feed paper is loaded, a manual-feed paper conveying unit, and a dustproof cover which covers the paper loading base being in the overhang state. The paper loading base has a lower end rotatably supported on one outer surface portion of the device main body, and is opened from an upper end thereof and disposed at a predetermined oblique angle or in a horizontal overhang state such that an overhang side becomes an upper side in an oblique direction. The manual-feed paper conveying unit is conveys the manual-feed paper on the paper loading base onto a paper conveyance path one by one. The dustproof cover includes a base which engages with the paper loading base, and an opening-and-closing cover which is rotatably connected to the base and is opened upwardly on the overhang side.

An image forming apparatus includes a reconveying unit including a reconveying roller; and a second transmission mechanism. The second transmission mechanism transmits a drive force to the reconveying roller and includes an input gear; an output gear; an intermediate gear including first and second gears; and first and second swinging gears. The first toothless part of the first gear and the second toothless part of the second gear are provided at such a position that, when the intermediate gear is rotated by a drive force transmitted from the input gear through the second swinging gear while the second swinging gear meshes with the second toothed part of the second gear and the output gear meshes with the first toothed part of the first gear, the first toothless part reaches a position confronting the output gear and then the second toothless part reaches a position confronting the second swinging gear.

A sheet conveying apparatus configured to convey a sheet includes a reversing portion, a reversing retraction portion provided in the reversing portion, a conveyance portion, a guide member provided in the reversing retraction portion, and a fan provided in the conveyance portion. The reversing portion conveys the sheet in a first direction and then a second direction opposite to the first direction. The reversing retraction portion temporarily retracts the sheet conveyed in the first direction. The conveyance portion has a conveyance path through which the sheet conveyed in the second direction passes and configured to convey the sheet. The guide member guides one surface of the sheet. The fan blows air toward the sheet guided by the guide member and is disposed to blow the air of the conveyance path in the conveyance portion toward the reversing retraction portion and along the guide member in the first direction.

An image forming system includes an image forming apparatus, an image reading apparatus, and a connecting conveyance path that branches from a second main conveyance path of the image reading apparatus and joins a first sub conveyance path of the image forming apparatus, and is configured to convey an original from the image reading apparatus to the image forming apparatus. The system controls conveyance of the original so that a first side becomes a side that faces an image forming unit if the first side of the original is designated as the image formation side or so that a second side becomes the side that faces the image forming unit if the second side of the original is designated as the image formation side.

An image forming apparatus, having an image forming device, a reversible roller rotatable in a first direction and a second direction, a motor, a switching assembly, is provided. The switching assembly has a planetary differential gear having an input gear, a first output gear, a second output gear, and a planetary gear; a first driving-force transmitter connecting the first output gear and the reversible roller; a second driving-force transmitter connecting the second output gear and the reversible roller; and a switcher. The switcher switches conditions of the switching assembly between a first condition, wherein the reversible roller is rotated in the first direction by the first output gear allowed to output the driving force to the first driving-force transmitter, and a second condition, wherein the reversible roller is rotated in the second direction by the second output gear allowed to output the driving force to the second driving-force transmitter.

A sheet feeding apparatus includes a first drive roller and a second drive roller disposed downstream of the first drive roller and configured to rotate at a peripheral speed greater than a peripheral speed of the first drive roller. The first drive roller includes a drive shaft and a roller portion. The roller portion is configured to contact the sheet and is movable relative to the drive shaft in an axial direction and a rotation direction of the drive shaft. One of the drive shaft and the roller portion of the first drive roller includes a protrusion protruding toward the other one of the drive shaft and the roller portion. The other one of the drive shaft and the roller portion of the first drive roller includes a recessed portion. The recessed portion includes a peripheral wall that defines an opening such that the protrusion is positioned in the opening.

A controller calculates a first time period T1 and a second time period T2. The first time period T1 is defined as a time period required for conveying the end portion of the sheet, which is conveyed in a first conveyance direction E, disposed on the upstream side in the first conveyance direction E up to a reversal position A3. The second time period T2 is defined as a time period required for conveying an end portion of the reversed sheet disposed on an upstream side in a second conveyance direction R from the reversal position A3 to a branching point A1.

An image forming apparatus includes a reconveying unit including a reconveying roller; and a second transmission mechanism. The second transmission mechanism transmits a drive force to the reconveying roller and includes an input gear; an output gear; an intermediate gear including first and second gears; and first and second swinging gears. The first toothless part of the first gear and the second toothless part of the second gear are provided at such a position that, when the intermediate gear is rotated by a drive force transmitted from the input gear through the second swinging gear while the second swinging gear meshes with the second toothed part of the second gear and the output gear meshes with the first toothed part of the first gear, the first toothless part reaches a position confronting the output gear and then the second toothless part reaches a position confronting the second swinging gear.

An image forming apparatus includes an image forming device, a switchback roller, and a re-conveying device. The re-conveying device includes a guide configured to change a conveying direction of a sheet conveyed by the switchback roller from a vertical direction to a horizontal direction and to guide the sheet in a width direction. The guide has a first guide surface and a second guide surface. The first guide surface and the second guide surface define a conveying path therebetween. The second guide surface is located closer to a center of a curvature of the conveying path than the first guide surface in a radial direction of the curvature. The first guide surface has a first area being planar and a second area downstream of the first area. The first area is configured to be contacted by a leading end of the sheet.