An image forming apparatus performs skew correction by bringing a leading end of a conveyed sheet in contact with a registration roller pair being in a stopped state and by forming a first loop with a loop roller pair, and thereafter, refeeds the sheet to an image former by adjusting timing. In a case of feeding a sheet with a length equal to or longer than a prescribed length, after having formed the first loop, the image forming apparatus forms a second loop in a loop accommodator that is disposed on an upstream side than the loop roller pair and accommodates a formed loop.

The present sheet conveying apparatus includes: a resist roller pair that corrects skew of a sheet conveyed from a sheet supplying unit; and a guide portion disposed at an upstream side relative to the resist roller pair in a sheet conveying direction, the guide portion including a first guide and a second guide disposed opposite to the first guide with a sheet conveying path therebetween, the second guide being located at a projection side of a curved portion formed in the sheet when a tip of the sheet is conveyed to a nip portion of the resist roller pair that is stopped, the second guide being divided into a plurality of divided guides in an axial direction of the resist roller pair, a flexible film being disposed to cover at least a portion of a space between the plurality of divided guides.

An image forming apparatus includes a photosensitive drum, a fixing unit including a fixing roller, a sheet ejection tray, a switchback roller, a re-feeding roller, a first frame, a second frame, a first motor, a first transmission mechanism, a second motor, and a second transmission mechanism. The switchback roller is configured to rotate in a forward direction to convey a sheet to the tray and in a reverse direction to convey the sheet back toward the photosensitive drum. The first motor and the first transmission mechanism are disposed to the first frame. The first transmission mechanism is configured to transmit the drive force from the first motor to the fixing roller. The second motor and the second transmission mechanism are disposed to the second frame. The second transmission mechanism is includes a clutch mechanism configured to intermittently transmit the drive force from the second motor to the re-feeding roller.

An image forming apparatus performs skew correction by bringing a leading end of a conveyed sheet in contact with a registration roller pair being in a stopped state and by forming a first loop with a loop roller pair, and thereafter, refeeds the sheet to an image former by adjusting timing. In a case of feeding a sheet with a length equal to or longer than a prescribed length, after having formed the first loop, the image forming apparatus forms a second loop in a loop accommodator that is disposed on an upstream side than the loop roller pair and accommodates a formed loop.

An image forming apparatus includes an image forming unit configured to form an image on a sheet, a duplex conveyance path through which the sheet having the image formed by the image forming unit on a first side passes when an image is formed on a second side that is a back side of the first side, a guiding member provided along the duplex conveyance path, a reversing roller pair capable of rotating in a forward direction and in a reverse direction, h, and a conveyance roller pair provided on the duplex conveyance path, wherein at least one of the reversing roller pair is inclined to the width direction so that, in the width direction, the side end of the sheet being conveyed by the reversing roller pair rotating in the reverse direction moves closer to the contact portion.

A sheet conveyance device includes a sheet conveyance passage, a first sheet stacking portion, a first feeding portion, a second feeding portion, a sheet detection mechanism, a driving portion, and a control portion. The first sheet stacking portion has a bottom face part and a lifting plate. The driving portion drives the first feeding portion when rotating forward and drives the second feeding portion when rotating reversely. The sheet detection mechanism has an actuator and a detection sensor. The control portion controls such that, for a sheet fed from the first sheet stacking portion, when the sheet is detected by the sheet detection mechanism, the driving portion rotates forward and, for a sheet conveyed from the second feeding portion, the driving portion rotates reversely and, when the detection sensor detects the actuator swinging at the detection position, the driving portion is switched to rotate forward.

A sheet characteristic detection device includes: a detector that is disposed on a sheet ejection path through which a sheet is ejected and that detects an electrical resistance value of the sheet; and a charge neutralizer that is disposed on a downstream side of the detector on the sheet ejection path and that neutralizes electric charge on the sheet.

A sheet conveyance device includes a sheet conveyance passage, a first sheet stacking portion, a first feeding portion, a second feeding portion, a sheet detection mechanism, a driving portion, and a control portion. The first sheet stacking portion has a bottom face part and a lifting plate. The driving portion drives the first feeding portion when rotating forward and drives the second feeding portion when rotating reversely. The sheet detection mechanism has an actuator and a detection sensor. The control portion controls such that, for a sheet fed from the first sheet stacking portion, when the sheet is detected by the sheet detection mechanism, the driving portion rotates forward and, for a sheet conveyed from the second feeding portion, the driving portion rotates reversely and, when the detection sensor detects the actuator swinging at the detection position, the driving portion is switched to rotate forward.

A sheet conveyance apparatus includes a first roller pair, a second roller pair, a third roller pair, and a control unit configured to execute a first mode in which skew correction of the sheet is performed by abutting a leading edge of the sheet against the second roller pair in a stopped state, and then the sheet is passed through the third roller pair without abutting the leading edge of the sheet against the third roller pair in a stopped state, and a second mode in which the leading edge of the sheet is passed through the second roller pair without abutting against the second roller pair in the stopped state, and then skew correction of the sheet is performed by abutting the leading edge of the sheet against the third roller pair in the stopped state.

A sheet conveyance apparatus includes a first conveying rotary member pair, an abutment portion, a first skewing rotary member pair, a second skewing rotary member pair, a switching mechanism, and a control unit. The control unit executes a first mode of controlling the second skewing rotary member pair to be in a nipping state in a sheet oblique conveyance state which is a state from when the first skewing rotary member pair starts an oblique conveyance of the sheet having been conveyed by the first conveying rotary member pair until an edge portion in a width direction of the sheet abuts the abutment portion, and a second mode of controlling the second skewing rotary member pair to be in a non-nipping state in the sheet oblique conveyance state.