According to an example aspect of the present invention, there is provided a method and apparatus for folding a stack of superposed sheets. The method comprises transferring the stack to a folding station, gripping a first part of the stack with a first grip and forming a crease on the stack to facilitate the folding. Then the at least a part of the stack is folded over the first part of the stack that has been gripped by utilizing the crease, the folded stack is gripped with a second grip and the folded stack is transferred from the folding station to a next handling stage and releasing the first grip.

In a printing system capable of supplying a sheet of a job having undergone print processing by the printing unit of a printing apparatus to a post-processing unit capable of executing at least a specific type of post-processing among a plurality of types of post-processes, when the target job requires the specific type of post-processing, the printing apparatus is inhibited from executing print processing of the job without explicitly determining a sheet necessary for the print processing of the job by a user using a user interface unit. When the target job does not require the specific type of post-processing, the printing apparatus is permitted to execute print processing of the job without explicitly determining a sheet necessary for the print processing of the job by the user using the user interface unit.

A post-processing apparatus includes a first conveyor, a second conveyor, a third conveyor, and a conveyance passage corrector. The first conveyor conveys a sheet conveyed along a first conveyance passage downstream from the first conveyor. The second conveyor conveys the sheet along a second conveyance passage. The third conveyor conveys the sheet along a third conveyance passage. The conveyance passage corrector includes a retracting mechanism to retract from a joining position at which the third conveyance passage joins to the first conveyance passage and turns a conveyance direction of the sheet toward the first conveyor when the sheet enters from the third conveyance passage to the first conveyance passage.

A folding machine comprises a blade folding unit having a first and a second folding roller, the folding roller axes thereof defining a folding roller plane, and having a folding blade which is oriented and is movable in a folding blade plane which is oriented perpendicularly to the folding roller plane and intersects the folding roller plane in an intersection line. The folding blade is arranged in a retracted position in or below a horizontal plane which comprises the intersection line.

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 turnable sheet stopper blocks and passes a sheet conveyed on a sheet guide, and includes a proximal portion, a distal portion connected to the end of the proximal portion, and a folding mechanism that connects the distal portion to the proximal portion. The sheet stopper transitions between first and second positions. In the second position, the proximal and distal portions integrally turn to the downstream side in the sheet conveyance direction to allow the sheet to pass. The sheet stopper transitions from the second position to a third position when a user draws out the sheet from an upstream side. In the third position, the distal portion folds toward the upstream side to allow the sheet to be drawn out. During transition from the second position to the third position, the edge of the distal portion is located on or away from an outer surface of the sheet guide.

An embodiment of this disclosure provides a folding apparatus configured to stack and fold a designated number of sheets at a time. The folding apparatus includes a conveyor configured to sequentially convey the designated number of sheets, a stacker configured to temporarily store a sheet conveyed by the conveyor to stack the designated number of sheets, a sheet folding device configured to fold the designated number of sheets at a time, and control circuitry. The control circuitry is configured to cause the sheet folding device to fold the stored sheet in response to an occurrence of a sheet jam upstream from the stacker in a direction of sheet conveyance, in processing the designated number of sheets.

An embodiment of this disclosure provides a folding apparatus configured to stack and fold a designated number of sheets at a time. The folding apparatus includes a conveyor configured to sequentially convey the designated number of sheets, a stacker configured to temporarily store a sheet conveyed by the conveyor to stack the designated number of sheets, a sheet folding device configured to fold the designated number of sheets at a time, and control circuitry. The control circuitry is configured to cause the sheet folding device to fold the stored sheet in response to an occurrence of a sheet jam upstream from the stacker in a direction of sheet conveyance, in processing the designated number of sheets.

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.