A sheet folding apparatus includes: a conveying roller conveying a sheet in a predetermined conveying direction; a folding roller pair disposed downstream of the conveying roller in the conveying direction and rotating while nipping a predetermined position of the sheet to form a fold; a conveying path for conveying the sheet in the conveying direction from the conveying roller to the folding roller pair; an abutting member moving downstream in the conveying direction and abutting against the predetermined position of the sheet to bend the sheet downstream; and a loop space where the sheet is bent between the conveying roller and folding roller pair in a direction crossing the conveying direction. The folding roller pair stops while nipping a front end of the sheet fed from to form a loop of the sheet in the loop space, and the abutting member moves to abut against the loop.

A post-processing apparatus includes: a binding device that performs a binding process on a bundle of sheets; a guide rail for moving the binding device; and a rotation mechanism that is arranged at a position adjacent to the guide rail and rotates the binding device that has moved on the guide rail along with movement of the binding device.

A sheet discharging apparatus includes a guide member configured to guide a lower surface of a sheet, a discharge roller pair, a stacking portion, and a first moving member and a second moving member each configured to move to a first position and a second position, the first position being a position where the first moving member and the second moving member protrude downstream of the discharge roller pair in the sheet discharge direction, the second position being a position located upstream of the first position in the sheet discharge direction. Support portions of the first moving member and the second moving member in the first position protrude upward in a height direction with respect to a tangent of a lower roller of the discharge roller pair when viewed in a sheet width direction.

A sheet post-processing apparatus includes a first stapler and a second stapler having different thicknesses of sheets on which a binding process can be performed. A control unit can perform a manual staple mode. If the first stapler is selected as a stapler for performing the binding process in the manual staple mode, the control unit controls the alignment member moving mechanism to move alignment members to a position defining a first insertion position for guiding the sheets to a first placing position. If the second stapler is selected, the control unit controls the alignment member moving mechanism to move the alignment members to a position defining a second insertion position for guiding the sheets to a second placing position.

A sheet binding device includes a first binding unit that performs a first binding process of binding a sheet bundle having a first thickness or less without using a staple, and a second binding unit that performs a second binding process of binding the sheet bundle having a second thickness or less exceeding the first thickness using a staple, the first binding process by the first binding device is preferentially executed when the thickness of the sheet bundle is the first thickness or less, and the second binding process by the second binding unit is executed when the thickness of the sheet bundle exceeds the first thickness and is equal to or less than the second thickness.

A sheet conveying device includes a sheet conveying passage, an upper conveying guide provided in the sheet conveying passage and facing the upper surface of a sheet, a lower conveying guide facing the lower surface of the sheet, a conveying member conveying the sheet along the sheet conveying passage, a sheet stack tray arranged above the upper conveying guide. The upper conveying guide is swingable up and down, with one end part of it in the sheet conveying direction or in the sheet width direction perpendicular to the sheet conveying direction serving as a pivot shaft. The sheet stack tray has a movable part making contact with the upper conveying guide at least when it swings, and the movable part is movable between a sheet receiving position where it forms a sheet stack surface and a retracted position where it has swung upward from the sheet receiving position.

A stapling device of a paper finishing device of one embodiment of the present disclosure includes a stapler including an entrance into which one side of paper is inserted, a moving part including a stapler moving bracket on which the stapler is seated and a moving roller installed on the stapler moving bracket, a driving part which moves the stapler moving bracket, a base frame on which the stapler moving bracket and the driving part are installed, and which includes a horizontal guide surface extending along the one side of the paper, a first corner stapling guide surface spaced apart from the horizontal guide surface, and a first inclined guide surface which diagonally connects the horizontal guide surface and the first corner stapling guide surface, and a position guide part which is installed on the base frame and includes a second corner stapling guide surface and a second inclined guide surface which diagonally connects the horizontal guide surface and the second corner stapling guide surface and is inclined to be opposite to the first inclined guide surface.

A sheet processing device includes a first conveyance passage, a first conveyor, a second conveyor, a folder, a second conveyance passage, and circuitry. The circuitry is configured to (1) cause the first conveyor and the second conveyor to convey the sheet nipping the sheet to warp the sheet between the first conveyor and the second conveyor, (2) guide the warped sheet to form a first fold on the sheet by the folder and circulate the sheet to the first conveyance passage, (3) cause the first conveyor and the second conveyor to convey the sheet while nipping the sheet again to warp the sheet between the first conveyor and the second conveyor, (4) guide the warped sheet to form a second fold on the sheet by the folder, and (5) cause the second conveyor to convey the sheet with the first fold and the second fold.

In a crimp-binding device, a sheet jam less occurs when binding processing is performed. A sheet crimp-binding device includes: a conveying path along which a sheet is conveyed in a predetermined conveying direction; a placing part on which the sheet conveyed along the conveying path is placed; a stack part provided at a location downstream from the placing part in the sheet conveying direction; a discharge unit that discharges the sheet from the placing part to the stack part; a shift unit that moves the sheet placed on a placing position on the placing part in a direction along a sheet surface and perpendicular to the sheet conveying direction; a crimp-binding unit that applies crimp-binding processing to sheets that have been moved in the direction perpendicular to the sheet conveying direction by the shift unit to a crimp-binding position; a recognition unit that recognizes count information of a sheet.

A postprocessing apparatus includes a horizontal alignment plate, a binder, a tray, and a shift actuator assembly. The horizontal alignment plate is positioned to align sheets in a sheet width direction. The binder binds sheets to form bound sheet bundles. The bound sheet bundles are stacked on the tray. The shift actuator assembly shifts the bound sheet bundles in the sheet width direction. A postprocessing controller controls the shift actuator assembly to shift the bound sheet bundles such that swollen portions of the bound sheet bundles are shifted inward of the horizontal alignment plate in the sheet width direction when the processed sheets are piled on the tray to the vicinity of the horizontal alignment plate.