A document sheet transportation device includes a feeding portion which feeds a document sheet from a document sheet placement portion toward a document sheet transportation path. The feeding portion includes a holder, a feeding member, a supporting body supported by the holder, a rotatable stopper member having a contact end portion allowed to contact a front end of a document sheet, and a biasing member which applies a biasing force to the stopper member. The stopper member is allowed to change a position among a first position in which the contact end portion contacts the front end of the document sheet, a second position which allows feeding of the document sheet by the feeding member, and a third position which is rotated in the first rotating direction from the second position. The biasing member applies the biasing force to the stopper member in a reverse second rotating direction.

A sheet conveying device includes a blocking member having a blocking surface with which a leading end of a sheet that is being conveyed comes into contact for obliquity correction. The blocking member is rotated by being pushed by the sheet against an urging force of a positioning unit that positions the blocking member to be in the standby position. The blocking member is rotatable to be in a sheet-passage-allowing orientation in which the sheet is allowed to pass. When a trailing end of the sheet that is being conveyed has passed the blocking member, the blocking member that is in the sheet-passage-allowing orientation rotates in a same direction as a sheet conveyance direction and is positioned to be in a standby position.

A sheet conveying device includes a blocking member having a blocking surface with which a leading end of a sheet that is being conveyed comes into contact for obliquity correction. The blocking member is rotated by being pushed by the sheet against an urging force of a positioning unit that positions the blocking member to be in the standby position. The blocking member is rotatable to be in a sheet-passage-allowing orientation in which the sheet is allowed to pass. When a trailing end of the sheet that is being conveyed has passed the blocking member, the blocking member that is in the sheet-passage-allowing orientation rotates in a same direction as a sheet conveyance direction and is positioned to be in a standby position.

In accordance with an embodiment, a sheet processing apparatus comprises a processing tray, a longitudinal alignment mechanism, a horizontal alignment mechanism and an interlocking mechanism. The processing tray can stack a sheet. The longitudinal alignment mechanism includes a rotatable paddle. The longitudinal alignment mechanism can align the sheets stacked on the processing tray in a sheet conveyance direction. The horizontal alignment mechanism includes a horizontal alignment plate movable in a sheet width direction orthogonal to the sheet conveyance direction. The horizontal alignment mechanism can align the sheets placed on the processing tray in the sheet width direction. The interlocking mechanism interlocks the paddle in the sheet width direction in synchronization with the movement of the horizontal alignment plate in the sheet width direction.

In accordance with an embodiment, a sheet processing apparatus comprises a processing tray, a longitudinal alignment mechanism, a horizontal alignment mechanism and an interlocking mechanism. The processing tray can stack a sheet. The longitudinal alignment mechanism includes a rotatable paddle. The longitudinal alignment mechanism can align the sheets stacked on the processing tray in a sheet conveyance direction. The horizontal alignment mechanism includes a horizontal alignment plate movable in a sheet width direction orthogonal to the sheet conveyance direction. The horizontal alignment mechanism can align the sheets placed on the processing tray in the sheet width direction. The interlocking mechanism interlocks the paddle in the sheet width direction in synchronization with the movement of the horizontal alignment plate in the sheet width direction.

In a sheet conveyor, a stopper piece of a sheet stopper temporarily stops a sheet supported on a sheet tray, and a pickup roller conveys the sheet from the sheet tray in a sheet conveying direction. A first sheet sensor disposed upstream of a registration roller and downstream of the stopper piece in the sheet conveying direction detects a leading edge of the sheet, and a second sheet sensor disposed downstream of the registration roller detects the leading edge of the sheet. A first contact member of the first sheet sensor receives the leading edge of the sheet. A second contact member of the second sheet sensor receives the leading edge of the sheet. The stopper piece, the first contact member, and the second contact member are offset from each other in a direction perpendicular to the sheet conveying direction and unaligned with each other in the sheet conveying direction.

In a sheet conveyor, a stopper piece of a sheet stopper temporarily stops a sheet supported on a sheet tray, and a pickup roller conveys the sheet from the sheet tray in a sheet conveying direction. A first sheet sensor disposed upstream of a registration roller and downstream of the stopper piece in the sheet conveying direction detects a leading edge of the sheet, and a second sheet sensor disposed downstream of the registration roller detects the leading edge of the sheet. A first contact member of the first sheet sensor receives the leading edge of the sheet. A second contact member of the second sheet sensor receives the leading edge of the sheet. The stopper piece, the first contact member, and the second contact member are offset from each other in a direction perpendicular to the sheet conveying direction and unaligned with each other in the sheet conveying direction.

A device for overlapping sheets includes at least one blower box and a supply table. Multiple sheets are guided into a region of the blower box consecutively, in the same transport direction, and are arranged at a distance from one another on the supply table. A blower nozzle is arranged in the blower box, on the side thereof facing the supply table. A blowing direction of the blower nozzle is oriented and parallel to the supply table and against the transport direction of the sheets. The supply table is arranged below the blower box and multiple blower nozzles are arranged in the blower box, one after the other, in the transport direction of the sheets, on the side thereof facing the supply table. A respective blowing direction of the blower nozzles is oriented in parallel to the supply table, and against the transport direction of the sheets.

A sheet conveyance apparatus includes first and second conveyance regulating portions which are respectively supported pivotably at different positions in a width direction, and an engagement portion provided on one of the first and second conveyance regulating portions and configured to be engaged with the other of the first and second conveyance regulating portions. In a state where a sheet whose length in the width direction is a first width is conveyed through a conveyance path, the sheet abuts the first conveyance regulating portion and pivots only the first conveyance regulating portion. In a state where a sheet whose length in the width direction is a second width that is greater than the first width is conveyed through the conveyance path, the sheet abuts the second conveyance regulating portion and pivots the second conveyance regulating portion while also pivoting the first conveyance regulating portion through the engagement portion.

An image forming apparatus includes: one paper cassette configured to accommodate a paper sheet; an image forming section provided above the paper cassette to form an image on the paper sheet; a main conveying path configured to convey the paper sheet; and a reverse conveying path configured to reverse the paper sheet, wherein the reverse conveying path includes: a first reverse conveying path provided side by side with the paper cassette to extend vertically; a second reverse conveying path configured to connect from the first reverse conveying path and extend below the paper cassette; a guide plate configured to open and close the first reverse conveying path and release pressure of a pair of paper conveying rollers; and an entry restricting unit provided at a boundary point between the first reverse conveying path and the second reverse conveying path to open and close a conveying course of the paper sheet.