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 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.

A sheet processing device includes a conveying unit, a presser, an end detector, and a setting unit. The conveying unit conveys a sheet having a crease formed therein. The presser presses the crease in the sheet. The end detector detects an end in a conveying direction of the sheet at a position upstream of the presser in the conveying direction. The setting unit sets a crease position where the crease is to be formed. Upon detection of the end in the conveying direction, the conveying unit conveys the sheet to a position where the crease faces the presser, on the basis of the crease position set by the setting unit. The presser presses the crease in the conveyed sheet.

A sheet processing device includes a conveying unit, a presser, an end detector, and a setting unit. The conveying unit conveys a sheet having a crease formed therein. The presser presses the crease in the sheet. The end detector detects an end in a conveying direction of the sheet at a position upstream of the presser in the conveying direction. The setting unit sets a crease position where the crease is to be formed. Upon detection of the end in the conveying direction, the conveying unit conveys the sheet to a position where the crease faces the presser, on the basis of the crease position set by the setting unit. The presser presses the crease in the conveyed sheet.

A pair of conveyance rollers are arranged for signatures. The signatures is conveyed through the pair of conveyance rollers to a stacking unit while being sandwiched from both sides thereof between the pair of conveyance rollers. In response to passage of a signature for a sheet stack through the pair of the conveyance rollers, the conveyance rollers is switched from conveyance rotation to intermittent rotation to cause the pair of the conveyance rollers to keep the signatures for a next sheet stack from being conveyed to the stacking unit. In response to the stacking unit becoming ready to receive the signatures for the next sheet stack, the conveyance rollers is switched from the intermitted rotation or the stop to the continuous rotation to cause the pair of the conveyance rollers to convey to the signatures to the stacking unit.

Each of the sheets is conveyed by a horizontal conveyance unit in a state of being overlapped with a next sheet from above. Each of the sheets is conveyed out of the horizontal conveyance unit in a state of being folded along a fold line with the fold line oriented upward, the fold line extending in a conveyance direction of the horizontal conveyance unit. An oblique conveyance unit receives the sheet from the horizontal conveyance unit and successively conveys the sheets in an oblique downward direction. A sensor is arranged to detect passage of the sheets at a position where steps pass. Each of the steps is formed by two sheets adjacent to each other diverted to the oblique downward direction by the oblique conveyance unit.

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.

The sheet pressing apparatus includes an inlet port configured to receive a sheet having a folding line; additional-folding rollers arranged downstream of the inlet port and configured to press the sheet at the folding line; 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 with respect to the lower folding guide from the pressing position; a second drive mechanism configured to move the additional-folding rollers along the folding line; and a restriction member configured to restrict, at a preset restriction position, the sheet thickness at the folding line to a value equal to or less than a prescribe value, while the additional-folding rollers are moving.

The sheet pressing apparatus includes an inlet port configured to receive a sheet having a folding line; additional-folding rollers arranged downstream of the inlet port and configured to press the sheet at the folding line; 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 with respect to the lower folding guide from the pressing position; a second drive mechanism configured to move the additional-folding rollers along the folding line; and a restriction member configured to restrict, at a preset restriction position, the sheet thickness at the folding line to a value equal to or less than a prescribe value, while the additional-folding rollers are moving.