A fold-enforcing assembly includes a fold-enforcing device, a moving device to move the fold-enforcing device in a direction of a fold of a sheet bundle, and control circuitry. The fold-enforcing device includes a pressing member pair to nip and press the fold of the sheet bundle in a direction of thickness, a pressing mechanism to pressurize and depressurize the pressing member pair, and a driver to drive the pressing mechanism. Controlled by the control circuitry, the moving device moves the fold-enforcing device in accordance with a size of the sheet bundle in the direction of the fold; pressing mechanism pressurizes the pressing member pair to press a first end portion of the sheet bundle in the direction of the fold; the moving device moves the fold-enforcing device to a second end portion of the sheet bundle; and pressing mechanism depressurizes the pressing member pair in the second end portion.

A sheet processing apparatus includes conveyers to convey a sheet. The conveyers include a registration conveyer which a plurality of sheets is to sequentially contact and is configured to bend a preceding sheet contacting the registration conveyer toward a direction in which the preceding sheet does not obstruct an entry of a following sheet to the registration conveyer when the conveyers overlay and convey the plurality of sheets after the plurality of sheets sequentially contacts the registration conveyer.

In a sheet folding apparatus for folding a sheet, a sheet is pushed at a predetermined position thereof by a push member while the sheet is being conveyed by a conveyance roller. The predetermined position of the sheet is guided to the nip section of a folding roller pair. Then, the sheet is nipped at the predetermined position thereof and folded by the folding roller pair.

A folding apparatus includes a folding device to fold a sheet bundle, an additional folding device, a conveyer, and control circuitry. The additional folding device includes a pressure roller disposed downstream from the folding device in a sheet conveyance direction and configured to press the sheet bundle after the folding device folds the sheet bundle and a sheet support member disposed opposite the pressure roller via the sheet bundle. The conveyer conveys the sheet bundle to a position at which the additional folding device presses the sheet bundle and hold the sheet bundle at the position. The control circuitry causes the additional folding device to perform additional folding processing on a first position of the sheet bundle, the conveyer to move the sheet bundle to a second position different from the first position, and the additional folding device to perform the additional folding processing at the second position again.

A sheet pressing device includes a carry-in port that receives a Z-folded sheet having two folds; an additional folding roller disposed downstream of the carry-in port to press the fold; a lower folding guide having a pedestal disposed opposite to the additional folding roller; a first moving mechanism that moves the additional folding roller between a pressing position at which the additional folding roller is made to approach the pedestal and a retreat position at which the additional folding roller is moved relative to the pedestal from the pressing position; a second moving mechanism that moves the additional folding roller along the fold; and a control part. The control part controls the second moving mechanism so as to increase the number of times the additional folding roller is moved along the fold when a sheet section is positioned between the additional folding roller and the fold.

A sheet bundle discharging apparatus, including: a guide unit configured to guide a sheet bundle with a spine as a leading end; a receiving unit configured to receive the spine of the sheet bundle guided by the guide unit; and a discharging unit configured to discharge the sheet bundle, wherein the receiving unit includes: a first surface configured to receive the spine at a first position; a second surface configured to push the sheet bundle in a rotation direction of the receiving unit; and a third surface configured to regulate a movement of the sheet bundle in the rotation direction while the receiving unit rotates from the first position to a second position, and wherein a friction coefficient between the sheet bundle and the third surface in a direction away from the first surface is larger than a friction coefficient between the first surface and the sheet bundle.

Disclosed herein is a sheet-folding apparatus which includes transporting rollers, folding rollers, a pushing member provided between the transporting rollers and the folding-rollers, and a guide unit for guiding the sheet to the folding-roller pair by using the pushing member.

Provided is a sheet folding apparatus for folding sheets, including: a feeding-roller pair; a loop-forming space provided downstream from the feeding-roller pair, for forming a sheet loop; a pushing member for pushing the looped sheet; a folding-roller pair for nipping a prescribed part of the sheet pushed by the pushing member, thereby to fold the sheet; and a path provided between the feeding-roller pair and the folding-roller pair, for guiding the sheet fed from the feeding-roller pair toward the loop-forming space.

A sheet pressing apparatus includes an inlet port for receiving a sheet having a folding line; additional folding rollers supported by a supporting member arranged downstream from the inlet port; a lower folding guide opposing the additional folding rollers; a first drive mechanism configured to move the additional folding rollers between a pressing position, at which the additional folding rollers approach the lower folding guide to press the sheet at the folding line, and a retreat position to which the additional folding rollers are moved from the pressing position, separating from the sheet; and a second drive mechanism configured to move the additional folding rollers along the folding line. The additional folding rollers are arranged such that one end of the folding line exists between the two additional folding rollers provided at one position and the additional folding roller at the other end position is arranged on the folding line.

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.