A sheet processing apparatus includes: an output unit that renders one side of a sheet convex and outputs the sheet, the sheet having the one side and other side; a first folding unit that mountain-folds the one side of the sheet, which is rendered to be convex, to form a first fold in the sheet; and a second folding unit that mountain-folds the one side of the sheet, which includes the first fold formed therein, to form a second fold in the sheet.

A printing system comprises: a printing unit configured to print an image on a sheet; and a control unit configured to control to perform creasing at a first pressure at a portion, corresponding to an edge of a spine cover, of the sheet on which the printing unit has printed the image, and perform creasing at a second pressure different from the first pressure at a portion of the sheet that corresponds to a hinge.

An image forming apparatus determines whether crease processing at a plurality of portions set on the sheet includes crease processing on two, front and back surfaces of the sheet; determines, if it is determined that crease processing includes crease processing on the two surfaces of the sheet, whether a connected post-processing apparatus that performs crease processing on a sheet can perform crease processing on the two, front and back surfaces of the sheet by one feeding; and controls, if it is determined that the connected post-processing apparatus cannot perform crease processing on the two surfaces by one feeding, to change, to one of the front and back surfaces of the sheet based on attribute information of the sheet, a surface to be processed in crease processing at the plurality of portions.

A floating clamp mechanism prevents sheets from migrating back from a lead edge registration wall during the compiling of sheets in a stacker. The floating clamp mechanism includes a spring loaded ball mounted in converging upper and lower tracks that act as a one-way clutch. This allows the incoming sheets to be scuffed with low force to the lead edge registration wall while simultaneously holding the registered sheets to the registration wall.

An image forming system capable of producing a center-folded or saddle-stitched brochure having punched holes at identical positions between the front and back sides thereof even when a saddle-stitching or center-folding position is set to a location shifted from a sheet center position. A puncher punches holes in a sheet. A finisher folds a sheet bundle formed by sheets each having the holes punched therein. A console sets an adjustment value for adjusting a folding position at which the sheet bundle is folded by the finisher, according to a manual operation. When the adjustment value is larger than a reference value, the puncher determines a punching position with respect to a folding position having the adjustment value reflected thereon and punches the holes in the determined punching position.

A sheet post-processing device includes a conveying section that conveys a paper sheet; a punch section that punches punch holes in the paper sheet conveyed by the conveying section; a stacker section that stores the paper sheet in which the punch holes are punched by the punch section; a binding section that binds a paper sheet bundle stored in the stacker section with a binding member; and a controller that controls the above sections. The controller selectively performs a ring binding mode and a direct binding mode. The ring binding mode is a mode in which punch holes are punched in the paper sheet by the punch section and then the binding member is made to penetrate the punch holes for binding. The direct binding mode is a mode in which the binding member is directly driven into the paper sheet bundle without punching the punch holes in the sheet.

A control portion of an image forming apparatus creates an image list for performing the perfect-binding imposition of the images of the pages on the sheets so that the scores formed on the sheets are on the external surface of the center-folded sheets, for the sheets each having a size twice the size specified as each of the sheets on which the images of the book body are to be formed, when a book-body stacking portion accommodates the sheets center-folded by a folding portion along scores formed for every sheet from a predetermined direction by a scoring portion for each of the sheets having the images formed thereon by the image forming portion, and a bookbinding portion uses a glue-on cover to perform case binding of a bundle of the sheets glued to the side of the spine.

A sheet conveying apparatus, including: a support portion configured to support a second sheet different from a first sheet among a plurality of sheets when the first sheet located undermost among the plurality of sheets conveyed by a conveyance portion is placeable on a placement portion; and a restriction unit configured to bring the second sheet into a first state in order to restrict downward movement of the second sheet at a restriction position located downstream of a support position at which the support portion supports the second sheet when the first sheet is placeable on the placement portion, and to bring the second sheet into a second state in order to remove or reduce a restriction force for restricting the downward movement of the second sheet to less than a restriction force in the first state after bringing the second sheet into the first state at the restriction position.

Folding information and printing surface information, included in content information of a sealed letter creation job, are compared with content printing conditions stored in a storage section, and an appropriate condition (a conveyance path after printing, execution/non-execution of image rotation, and printing page order) is selected such that the position of a window of a windowed envelope is aligned with the position of specifying information printed on a print sheet P to be a content when the print sheet P is enclosed in the envelope. A convey section and a printing section are controlled based on the selected content printing condition.

A booklet processing apparatus includes a pressing member and a rotating unit. The pressing member presses a folded portion of a booklet formed to extend in one direction and having the folded portion on the downstream side in the one direction. The pressing member is provided so as to be rotatable about a rotary shaft that extends along the folded portion. The rotating unit rotates the pressing member so as to move a portion of the pressing member that confronts the folded portion downstream in the one direction so that the portion of the pressing member that confronts the folded portion is changed to a different portion.