A medium reversing and discharging device includes a discharger that discharges a medium in a paper discharge direction from a discharge outlet, a holder that holds and reverses the medium, and a driver that moves the holder such that when a first plane along a portion of the medium in contact with the discharge outlet does not intersect with a second plane along a portion of the medium held by the holder on a downstream side in the paper discharge direction of the discharge outlet a moving speed at which the holder moves is lower than a discharge speed at which the medium is discharged from the discharge outlet.

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.

An image forming system includes an image forming unit for forming a first toner image and a second toner image on a first surface and a second surface of a recording medium by using toner containing wax; a pressure-bonding unit for pressure-bonding the recording medium folded in two by applying heat and pressure to the recording medium, an inner surface of the recording medium folded in two being pressure-bonded via an adhesive medium, one of the first surface and the second surface being the inner surface of the recording medium folded in two, the pressure-bonding unit pressure-bonding the recording medium folded in two via an adhesive member; and a control unit for determining an image forming order so that an image is formed on an outer surface of the recording medium folded in two, and then on the inner surface of the recording medium folded in two.

A sheet folding apparatus includes a folding roller pair that forms a first fold line owing to that the folding roller pair nips a first position of the sheet, which has a loop to be formed on an upstream side of the folding roller pair due to continuous conveyance of the sheet by a conveyance roller pair in a stopped state in which a front end of the sheet being conveyed from the conveyance roller pair is nipped by the folding roller pair, as starting conveyance of the sheet while a pushing plate is pushing the sheet and moving toward the folding roller pair, and thereafter, forms a second fold line owing to that the folding roller pair nips a second position of the sheet with the loop formed as aligning with a rear end of the sheet.

A post-processing apparatus includes: a processing unit configured to pull in a recording medium transported from an upstream apparatus and perform processing on the recording medium; a discharge unit to which the recording medium processed by the processing unit is discharged; and a lifting drive device configured to, in a case where a folded recording medium is pulled into the processing unit, move the discharge unit downward such that a height of the discharge unit is lower than a height of the discharge unit in a case where an unfolded recording medium is pulled into the processing unit.

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.

A sheet stacking tray includes a first conveyor, a second conveyor, a sheet stopper, a first full-load detector, a second full-load detector, and a plurality of motors. The plurality of motors maintain the sheet stopper at a protruding position to block a sheet conveyed by the first conveyor until the first full-load detector outputs a signal indicating that a sheet bundle is fully loaded, shift the sheet stopper to a lowered position to allow the sheet bundle to pass when the first full-load detector outputs the signal indicating that the sheet bundle is fully loaded, drive the first conveyor and the second conveyor together to convey the sheet bundle when the sheet stopper shifts to the lowered position, and stop the second conveyor and drive only the first conveyor, when the second full-load detector detects a leading edge of the sheet bundle.

A sheet post-processing device includes a folding portion, a discharge portion, a stacking tray, a shift unit, a pair of alignment members, and a controller. The pair of alignment members include first and second alignment members at one and the other side of sheets stacked on the stacking tray. When a sheet bundle sorted and stacked on the stacking tray includes a folded sheet, executes a second alignment mode in which it performs, for sheets shifted to a first position at one side on the stacking tray, alignment with only the first alignment member and, for sheets shifted to a second position at the other side, alignment with only the second alignment member, or does not perform alignment process.

A sheet stacking tray includes a first conveyor, a second conveyor, a sheet stopper, a first full-load detector, a second full-load detector, and a plurality of motors. The plurality of motors maintain the sheet stopper at a protruding position to block a sheet conveyed by the first conveyor until the first full-load detector outputs a signal indicating that a sheet bundle is fully loaded, shift the sheet stopper to a lowered position to allow the sheet bundle to pass when the first full-load detector outputs the signal indicating that the sheet bundle is fully loaded, drive the first conveyor and the second conveyor together to convey the sheet bundle when the sheet stopper shifts to the lowered position, and stop the second conveyor and drive only the first conveyor, when the second full-load detector detects a leading edge of the sheet bundle.

A sheet folding processing device includes a folding processing mechanism that includes a folding roller pair for forming a plurality of folds on the sheet conveyed in a predetermined sheet conveying direction to produce Z-fold, additional folding rollers and a lower folding guide. The additional folding rollers and the lower folding guide are arranged on the downstream side of the folding roller pair in the sheet conveying direction to face each other and cooperate with each other to press the folds. The interval between the folding roller pair and the additional folding rollers is determined such that when the leading fold as viewed in the sheet conveying direction is pressed between the additional folding rollers and the lower folding guide, the sheet part having a plurality of layers of sheet where the sheet is folded between the additional folding rollers can also be held between the folding roller pair.