A sheet processing device for pressing a fold line formed in a sheet, the sheet processing device comprises a pressing portion configured to press a sheet while rotating about a rotation axis. The pressing portion includes a pressing unit having a projecting shape, disposed over a predetermined range in a direction of the rotation axis to have a position in a rotation direction about the rotation axis changed according to the direction of the rotation axis, and an impact absorbing member provided at a part of the pressing unit of the pressing portion, abutting on the sheet at first in the rotation direction of the pressing portion, the impact absorbing member configured to reduce impact upon abutting on the sheet.

A folding processing unit in a sheet post-processing device comprises a first conveying path, upstream side conveying rollers, downstream side conveying rollers, folding rollers between the upstream side conveying rollers and the downstream side conveying rollers, and the second folding rollers. The folding rollers fold a sheet at the first nip portion between the two rollers. The second folding rollers are placed at a downstream side of the first nip portion. An edge face detection sensor for detecting the edge face of the sheet is placed on the first conveying path, at a downstream side of the first nip portion. The second folding rollers pinch the sheet folded by the first nip portion at the second nip portion, to further fold the sheet, based on the detection result of the edge face detection sensor. Herewith, degree of accuracy for folding behavior improves.

A sheet processing apparatus is configured to press a fold line that is formed on a sheet. The sheet processing apparatus includes: a sheet supporting unit configured to support the sheet in a pressing direction for pressing the fold line; a pressing unit configured to press the fold line that is formed on the sheet that is supported by the sheet supporting unit; and a pressing-force generating unit configured to generate a pressing force for pressing the sheet supporting unit against the pressing unit at a central part in a direction along which the fold line is formed.

A sheet processing apparatus is configured to press a fold line that is formed on a sheet. The sheet processing apparatus includes: a sheet supporting unit configured to support the sheet in a pressing direction for pressing the fold line; a pressing unit configured to press the fold line that is formed on the sheet that is supported by the sheet supporting unit; and a pressing-force generating unit configured to generate a pressing force for pressing the sheet supporting unit against the pressing unit at a central part in a direction along which the fold line is formed.

The sheet discharge device includes: a sheet discharge part; a sheet discharge tray having a tray upper surface and a rear wall portion; a fullness detection sensor for detecting that a height of a stack surface of folded sheets; and a first sheet presser member and a second sheet presser member for pressing a rear end side and a fore end side in a discharge direction, of the folded sheet. In a first pressing position in which the first sheet presser member extends from above the detection sensor to below the detection region, and is brought into contact with the folded sheet of a minimum size stacked on the tray upper surface. When a stack number of the folded sheets has exceeded a specified number, the first sheet presser member is retracted upward from the first pressing position by the rise of the stack surface.

A sheet processing apparatus is configured to press a fold line that is formed on a sheet. The sheet processing apparatus includes: a sheet supporting unit configured to support the sheet in a pressing direction for pressing the fold line; a pressing unit configured to press the fold line that is formed on the sheet that is supported by the sheet supporting unit; and a pressing-force generating unit configured to generate a pressing force for pressing the sheet supporting unit against the pressing unit at a central part in a direction along which the fold line is formed.

A post-processing device performs a first and a second folding processes on a sheet. The post-processing device comprises a pair of conveying rollers on a first conveying path, a first pair of folding rollers at a downstream side of the pair of conveying rollers on the first conveying path to perform a second folding process on the sheet, a second pair of folding rollers on a second conveying path branched from the first conveying path between the pair of conveying rollers and the first pair of folding rollers, to perform a first folding process on the sheet, and a guide at a closure position which shuts the first conveying path, to guide the sheet conveyed from the pair of conveying rollers to the first pair of folding rollers.

A sheet processing apparatus is configured to press a fold line that is formed on a sheet. The sheet processing apparatus includes: a sheet supporting unit configured to support the sheet in a pressing direction for pressing the fold line; a pressing unit configured to press the fold line that is formed on the sheet that is supported by the sheet supporting unit; and a pressing-force generating unit configured to generate a pressing force for pressing the sheet supporting unit against the pressing unit at a central part in a direction along which the fold line is formed.

A sheet processing device includes: a folder that forms a plurality of folds on a sheet such that a fold part and a part with no fold of the sheet overlap with each other; a conveyance unit that conveys the sheen on which the folds are formed by the folder; and a pressing part that presses the fold part of the conveyed sheet in which the fold part and the part with no fold overlap with each other, from a side on which the fold part is located.

A sheet processing device includes an upstream device, a downstream device, and a controller as circuitry. The upstream device includes multiple rollers to convey a sheet in a conveyance direction and perform a sheet processing. The downstream device is downstream from the upstream device in the conveyance direction. The downstream device includes a sheet sensor to detect the sheet. The controller controls a timing to rotate the multiple rollers of the upstream device to perform the sheet processing in response to a detection of the sheet by the sheet sensor.