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.

The folding pocket device for a buckle folding machine includes a folding pocket having a feed-in aperture enabling a sheet to run therethrough in a running-in direction into a pocket space of the folding pocket. A sheet stop device includes a sheet stop extending essentially transversely to the running-in direction in the pocket space, which is displaceable in the running-in direction and in the opposite direction. A sheet directing device includes a diverting device, which is displaceable from a clearance position in which the diverting device opens up the way to the feed-in aperture into the folding pocket to a diverting position in which the diverting device blocks the feed-in aperture in order to divert a sheet. In order to achieve quick switching from the clearance position to the diverting position, the diverting device can be displaced from the clearance position to the diverting position by the sheet stop when the sheet stop is displaced opposite to the running-in direction.

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.

A sheet folding device includes: a sheet receiving unit with a pair of guide plates to restrict opposite sides of one or a plurality of stacked sheets and a striking portion to be struck by leading ends of the introduced sheets; a roller group to introduce the sheets into the sheet receiving unit, strike the introduced sheets on the striking portion to form a bent portion on the sheets, and nip and fold the formed bent portion and discharge the sheets from the sheet receiving unit; and a curve forming unit to form a curved portion on the sheets, at a position closer to the leading ends of the sheets than a position where the bent portion to be folded by the roller group is formed, the curved portion being curved in a width direction perpendicular to a direction of transfer of the sheets.

Provided is a sheet folding device comprising a deceleration means which halts a sheet by pressing. A pressure member such as rubber is disposed upon the leading end of a rod-shaped member which is rotatably retained. A sheet is decelerated by the pressure member being applied obliquely to the sheet. The entire surface of the rubber does not make close contact with paper, and thus, a wrinkle is not formed in the paper. It is possible to ensure a stable folding location.