A sheet feeding device (4) includes a placing plate (34) on which a sheet is placed; a pickup roller (71) which feeds the sheet to a conveying path (25); a lift member (36) which is turned around a rotating shaft (46) to elevate the placing plate (34) and to make an downstream side end portion of an uppermost sheet in a conveying direction come into contact with the pickup roller (71); a drive unit (37) which rotates the rotating shaft (46); a variable resistor (54) which changes an electric resistance value depending on a rotating angle of the rotating shaft (46); and a control part (77) which calculates the rotating angle of the rotating shaft (46) using the electric resistance value measured by the variable resistor (54) and detects an amount of the sheets based on the calculated rotating angle.

A sheet feeding device (4) includes a placing plate (34) on which a sheet is placed; a pickup roller (71) which feeds the sheet to a conveying path (25); a lift member (36) which is turned around a rotating shaft (46) to elevate the placing plate (34) and to make an downstream side end portion of an uppermost sheet in a conveying direction come into contact with the pickup roller (71); a drive unit (37) which rotates the rotating shaft (46); a variable resistor (54) which changes an electric resistance value depending on a rotating angle of the rotating shaft (46); and a control part (77) which calculates the rotating angle of the rotating shaft (46) using the electric resistance value measured by the variable resistor (54) and detects an amount of the sheets based on the calculated rotating angle.

A roll-shaped medium transport device includes: a medium supply unit that keeps a roll body formed by winding a roll-shaped medium on a support shaft, and unwinds and supplies the roll-shaped medium; a transport unit that transports the roll-shaped medium unwound from the roll body; a rotation detecting unit that detects rotation of the support shaft; a rotation unit that rotates the support shaft; and a determination unit that determines abnormality of a transport state of the roll-shaped medium on the basis of the rotation detecting unit when the rotation unit rotates the support shaft, when the rotation detecting unit does not detect the rotation of the support shaft in a state where a transport operation of the roll-shaped medium is performed by the transport unit.

A conveyance control unit is provided with a conveyance request unit configured to transmit a conveyance request signal to a paper conveyance device at a conveyance request timing corresponding to a processing cycle of a downstream paper processing device, a passage information reception unit configured to receive a paper passage signal indicating that paper has been sent out from the paper conveyance device, and the determination unit configured to determine whether a conveyance delay has occurred based on timing when the paper passage signal was received. The conveyance request unit is configured to transmit the conveyance request signal at the conveyance request timing corresponding to the next processing cycle when it is determined that a conveyance delay has not occurred, and the conveyance request unit is configured not to transmit the conveyance request signal at the conveyance request timing corresponding to the next processing cycle when it is determined that a conveyance delay has occurred.

A medium conveying apparatus includes a first roller to convey a medium, a movement mechanism to move the first roller between a first position in contact with the medium and a second position spaced apart from the medium, a second roller located on a downstream side of the first roller in a medium conveying direction to convey the medium, and a processor to detect a skew of the conveyed medium, and control the movement mechanism to move the first roller to the second position, and correct the skew of the medium using the second roller when the skew of the medium is detected.

A medium feeding mechanism includes: a feeder that feeds a medium; a transport path that is coupled to the feeder; a transporter that transports the medium through the transport path; a transport drive that drives the transporter; an entry detection sensor that detects when the medium fed from the feeder has entered the transport path; a take-in transporter that takes in the medium transported by the transporter; and a transport controller that controls the feeder and the take-in transporter, wherein when the entry detection sensor detects entry of the medium at a time that falls within a first range set in advance, the controller controls the take-in transporter so as to take in the medium, and when the entry detection sensor detects entry of the medium at a time that falls within a second range following the first range.

A sheet post-processing device is connected to a punch processing unit. The punch processing unit includes a skew detection unit and a punch unit. The skew detection unit detects a skew amount of a sheet. The punch unit forms punch holes at positions of the sheet according to the skew amount. The sheet post-processing device includes a processing tray, a paddle, a driver, and a control unit. The sheet of which the skew amount is detected by the skew detection unit is mounted on the processing tray. The paddle conveys the sheet on the processing tray by a paddle operation. The driver drives the paddle to perform the paddle operation. The control unit is configured to operate the driver to control a number of times the paddle operation is performed by the paddle based on the skew amount.

In order to provide a configuration capable of suppressing reductions in productivity of sheets, a pair of regulation guides are capable of guiding opposite end edges in a sheet width direction Y of a sheet S1 conveyed by a conveyance belt and spheres, while being nipped. Further, the pair of regulation guides are capable of shifting to guide positions for guiding the opposite end edges of the sheet, and retract positions retracted from the opposite end edges of the sheet more than the guide positions. A sheet detecting sensor is disposed on the downstream side of the conveyance belt in a conveyance direction X to detect the presence or absence of the sheet.

In order to provide a configuration capable of correcting skew and lateral displacement of a sheet, a pair of regulation guides are capable of guiding opposite end edges in a sheet width direction of a sheet S conveyed by a conveyance belt and spheres, while being nipped. Further, the pair of regulation guides are capable of shifting to guide positions for guiding the opposite end edges of the sheet, and retract positions retracted from the opposite end edges of the sheet more than the guide positions, wherein a control section conveys the sheet by the conveyance belt in a state in which the pair of regulation guides are positioned in the retract positions, and brings a front end of the sheet in a state of being conveyed by the conveyance belt into contact with a conveyance roller pair with drive halted.

In order to provide a configuration capable of stably performing conveyance of sheets, a pair of regulation guides are capable of guiding opposite end edges in the sheet width direction Y of a sheet S conveyed by a conveyance belt and spheres, while being nipped. Further, the pair of regulation guides are capable of shifting to guide positions for guiding the opposite end edges of the sheet and retract positions retracted from the opposite end edges of the sheet more than the guide positions. In shifting the pair of regulation guides from the retract positions to the guide positions, a guide shift section causes the one of regulation guides to arrive at the guide position after the other of regulation guides arrives at the guide position.