According to an embodiment, a sheet folding apparatus comprises a first roller, a second roller configured to be energized to the first roller, form a nip section together with the first roller, fold a sheet in half together with the first roller through the nip section and convey the sheet folded in half together with the first roller and a pressing force adjusting mechanism configured to be capable of increasing and decreasing a pressing force generated at the nip section. The pressing force adjusting mechanism causes a pressing force in a state of being conveying the sheet folded in half to be lower than that in a state of being folding the sheet in half.

A post-processing device performs a first and a second folding processes on a sheet. The post-processing device comprises a pair of conveying rollers on a first conveying path, a first pair of folding rollers at a downstream side of the pair of conveying rollers on the first conveying path to perform a second folding process on the sheet, a second pair of folding rollers on a second conveying path branched from the first conveying path between the pair of conveying rollers and the first pair of folding rollers, to perform a first folding process on the sheet, and a guide at a closure position which shuts the first conveying path, to guide the sheet conveyed from the pair of conveying rollers to the first pair of folding rollers.

A sheet processing apparatus, including: a conveyance path in which a sheet is conveyed in a predetermined conveyance direction; a rotary member pair configured to nip the sheet conveyed in the conveyance path and rotate to perform folding processing on the sheet; and a guide portion provided between one rotary member of the rotary member pair and the conveyance path and configured to guide a downstream edge of a sheet conveyed in the predetermined conveyance direction, wherein, in case that a sheet is conveyed in the conveyance path in the predetermined conveyance direction, the guide portion guides a downstream edge of the sheet in the predetermined conveyance direction in a state in which the guide portion is held in contact with the one rotary member.

A sheet processing apparatus, including: a rotary member pair configured to nip a sheet conveyed in a conveyance path and rotate to fold the sheet; and a guide portion provided between one rotary member of the rotary member pair and the conveyance path, the one rotary member including: a first part; and a second part, wherein a first distance between the first part and a rotary shaft center of the one rotary member is greater than a second distance between the second part and the rotary shaft center, and wherein the guide portion is positioned at a first position in case that the second part is positioned at a first rotational position, and the guide portion is positioned at a second position different from the first position in a distance from the rotary shaft center in case that the second part is positioned at a second rotational position.

In accordance with an embodiment, a sheet glue binding processing apparatus comprises a processing tray, a glue binding section and a sheet detection section. The processing tray is used to stack a sheet in such a manner that the end of the binding margin side of the sheet is fed to a positioning section. The glue binding section is configured at the positioning section side of the processing tray to adhere glue material to the binding margin of the sheet already stacked on the processing tray. The sheet detection section detects whether or not the binding margin of the first sheet to be stacked on the processing tray is located at a specific position of the processing tray.

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 sheet folding apparatus for folding a sheet is provided with a hold member that holds a transported sheet in a substantially cylindrical shape, a shift member that presses the outer circumferential surface of the sheet of the substantially cylindrical shape held by the hold member to make a substantially flat shape, and a discharge section that further presses the sheet made the substantially flat shape by the shift member, while discharging in a direction crossing a transport direction. By this means, it is possible to provide a relatively compact sheet folding apparatus.

A printing control apparatus according to one aspect of this invention controls to print images on sheets based on image data of a plurality of pages, generate a bookbinding product by executing folding processing for the image-printed sheets, and output the bookbinding product. The printing control apparatus further accepts the position of an insertion sheet to be inserted into the sheets for which the folding processing is executed, and controls to output a plurality of bookbinding products by using, as a reference, the accepted position of the insertion sheet.

An image forming apparatus includes a first development part provided with an image forming developer containing image forming pigments and image forming macromolecular compound, a second development part provided with a bonding developer containing bonding macromolecular compound, a transfer part transferring the image forming developer to a surface of a medium, and a fuser part fusing the image forming developer to the medium. Wherein heating temperature T1 ( C.) for the image forming developer by the fuser part and heating temperature T2 ( C.) for the bonding developer by the fuser part satisfy a condition expressed by Eq. (1) below, and solubility parameter 1 of the image forming macromolecular compound and solubility parameter 2 of the bonding macromolecular compound satisfy a condition expressed by Eq. (2) below.

10 C.T1T230 C.(1)

5.9|12|7.4(2)