When using a flipping wheel to flip sheets of weak or long media, there is a risk that these sheets collapse upon themselves. To reduce this risk, a method of stacking sheets includes flipping a sheet while holding its leading edge and bringing the leading edge down towards a stack support; bringing a trailing portion of the sheet into contact with a guide member positioned over the stack support; forming an overpressure in an inner volume of the bent sheet during flipping, while its trailing portion is in contact with the guide member; and maintaining the overpressure and contact while a trailing edge of the sheet travels along the guide member.

A post-processing device includes a processing tray, an aligning plate, a transport section, a feeding section, and a pressing section. A sheet before being subjected to stapling processing by a stapler is to be mounted on the processing tray. The aligning plate aligns ends of a plurality of sheets. The transport section transports the sheet toward the aligning plate. The feeding section is provided between the transport section and the aligning plate and feeds the sheet in a transport direction. The pressing section is provided between the transport section and the aligning plate and applies, to the sheet, a pressing force having a component in a direction opposite from the transport direction. Further, the pressing section applies the pressing force to the sheet before the feeding section applies a feeding force to the sheet.

An image forming apparatus includes an image forming device, a sheet stacking portion, a side projecting portion, a rear projecting portion, and a blower. The sheet stacking portion is disposed above the image forming device to stack sheets after image forming. The side projecting portion protrudes upward from a lateral end of the image forming device and includes a sheet ejection passage to convey the sheet after image forming and a sheet ejection port to eject the sheet toward the sheet stacking portion. The rear projecting portion protrudes upward from a rear end of the image forming device and forms a space together with the side projecting portion. The blower is disposed in the space to face the rear projecting portion, takes in air from a side facing the rear projecting portion, and exhausts the air from the sheet ejection port toward the sheet ejected toward the sheet stacking portion.

A postprocessing device is attached to an image forming apparatus. The postprocessing device includes a processing tray, a sheet processor, and a fan. The processing tray is for stacking thereon sheets on which an image has been formed and which is transported from the image forming apparatus. The sheet processor performs predetermined postprocessing on the sheets stacked on the processing tray. The fan forms an air layer between an upper face of the sheets already stacked on the stacking surface of the processing tray and a lower face of a sheet newly placed on the processing tray, by emitting air in a transport direction of the sheet, from an upstream side in the transport direction toward the stacking surface.

A method operates a facility, which serves for the continuous production of multiple gang runs for forming individual signatures or signature packs from which type-specific print products are made in a downstream print further processing machine. An endless web is the basis for the formation of these multiple gang runs. The endless web, in the non-folded state, is imparted complementary handling by facility-internal means according to the following criteria: i) in a 2-gang run, the individual signatures or the folded signature packs are only deflected in a second longitudinal air folding station disposed downstream of the first longitudinal air folding station; and ii) in a 3 or 4-gang run, the individual signatures or the folded signature packs are additionally folded in a second longitudinal air folding station disposed downstream of the first longitudinal air folding station.