A sheet conveyance apparatus includes a rotary member and an opposing member to convey a sheet in a conveyance nip, and an abutting member abutting a surface of the rotary member, which is supported between a first position and a second position with respect to the abutting member. When the sheet is not passing through the conveyance nip the rotary member is positioned at the first position and abuts the opposing member, and when the sheet is passing through the conveyance nip the rotary member is positioned at the second position which is more separated from the opposing member than the first position. The abutting member abuts the rotary member regardless of which of the first position and the second position the rotary member is positioned at, and the opposing member and the abutting member are supported so they do not move in a radial direction of the rotary member.

An image forming apparatus includes an image forming device, a transport route, a purge transport route, an image forming transport route, a transport roller, and a blowing machine. The image forming device forms an image on a sheet. The transport route extends to a predetermined position. The purge transport route extends to a downstream side in a sheet transport direction, from the predetermined position. The image forming transport route is branched from the purge transport route at the predetermined position, and extends toward the image forming device. The transport roller transports the sheet along the transport route, and along one of the purge transport route and the image forming transport route. The blowing machine delivers the sheet to one of the purge transport route and the image forming transport route, by blowing air to the sheet being transported along the transport route.

An image forming apparatus includes a sheet accommodation unit, a feed roller to feed a sheet along a conveyance path, a first encoder to detect rotation of the feed roller, a conveying roller downstream of the feed roller, a second encoder to detect rotation of the conveying roller, and a motor to drive the feed roller and the conveying roller. A first clutch switches between connecting and disconnecting the paper feed roller to the motor. A second clutch switches between connecting and disconnecting the motor to the conveying roller. A first sensor detects the sheet at a first position. A second sensor detects the sheet at a second position. A control unit controls the motor based on output from the first encoder when the sheet is at the first position and output from the second encoder when the sheet is at the second position.

An image processing apparatus includes a transmitter, a receiver, a comparison circuit, and a control unit. The transmitter transmits an ultrasonic wave to a conveyance path through which a sheet is conveyed. The receiver faces the transmitter with the conveyance path in between, and receives the ultrasonic wave transmitted by the transmitter. The comparison circuit compares a level signal indicating a reception level of the ultrasonic wave received by the receiver with a threshold signal for determining whether or not the sheet is double-fed in the conveyance path, and outputs a comparison result signal according to the comparison result. The control unit determines whether or not there is a possibility of a defect in the double feed detection function of detecting double feed based on the comparison result signal and the level signal.

A medium feeding apparatus includes a feed roller that feeds media. A separation roller nips the media together with the feed roller to separate it and is rotated in a first direction to feed the media. A motor applies driving torque to the separation roller in a second direction opposite to the first direction. A torque limiter, when rotation torque applied to the separation roller in the first direction exceeds a preset upper torque limit, causes the separation roller to rotate at idle in the first direction independently of the driving torque. During feeding operations, including feeding of first and second media, a controller that controls the motor provides a break period in which the motor is not driven. The break period contains the timing when a rear edge of the first medium leaves a nip position between the feeding and separation rollers.

A medium transport apparatus includes a first roller configured to apply feeding force to a medium in a medium transport path for transporting the medium, a second roller disposed on an upstream side of the first roller in a medium transport direction in the medium transport path, the second roller being configured to apply feeding force to the medium, a third roller configured to be switched between a first position at which the medium is to be nipped with the second roller and a second position at which the nipping of the medium is to be released, a switching section configured to switch a position of the third roller, and at least one protruding member protruding from an outer circumferential surface of the second roller, the protruding member being configured to separate the medium from the outer circumferential surface of the second roller in the medium transport path.

In an image-forming apparatus, when a sheet length of a first sheet is shorter than or equal to a predetermined length, a controller supplies power to an electromagnetic clutch to convey the first sheet and a second sheet so that a sheet gap of the second sheet is equivalent to a first gap. When the sheet length of the first sheet is longer than the predetermined length, the controller supplies power to the electromagnetic clutch to successively convey a first number of sheets so that the sheet gap of each of the first number of sheets is equivalent to the first gap. After the first number of sheets has been conveyed, the controller supplies power to the electromagnetic clutch to convey at least one sheet so that the sheet gap of each of the at least one sheet is equivalent to a second gap greater than the first gap.

A sheet feeding apparatus includes a supporting portion to support a sheet, a feeding portion to feed the supported sheet, and a base member opposed to the supporting portion so the sheet is supported by the supporting portion between the supporting portion and the base member. A regulation unit includes a regulation portion to regulate a position of an edge portion of the supported sheet and moves in a moving direction, and a sensor outputs an output value that changes in accordance with an amount of movement of the regulation unit. The sensor and the regulation unit are supported by the base member, and the sensor is supported by the base member at a position above an abutment position between the sheet supported by the supporting portion and the feeding portion in a gravity direction.

A sheet conveying device includes a first duct, a second duct, and a switching member. The first duct is disposed at a first side of a sheet conveyance passage to face a first face of a sheet passing the sheet conveyance passage and has a first air blowing port through which air is blown toward the sheet conveyance passage. The second duct is disposed at a second side of the sheet conveyance passage to face a second face of the sheet passing the sheet conveyance passage and has a second air blowing port through which air is blown toward the sheet conveyance passage. The switching member is disposed downstream from the first and second air blowing ports in a sheet conveyance direction and configured to switch the sheet conveyance passage. No pair of rollers is disposed between the switching member and each of the first and second blowing ports.

A sheet conveyance apparatus includes a receiving member to hold a sheet pressing portion and receive a reaction force of an urging portion for urging the sheet pressing portion toward the first sheet guide, a detection unit having a first detection portion disposed on a first sheet guide, and a second detection portion facing the first detection portion and disposed on a second sheet guide. The detection unit changes an output value based on presence and absence of the sheet at a detection position in a sheet conveyance path, wherein the second guide provided with the second detection portion, and a receiving member are movably disposed with respect to the first guide provided with the first detection portion respectively, and are positioned with respect to the first guide independently from each other, and wherein the receiving member is pivotably supported around the pivot axis independently from the second guide.