A sheet folding apparatus includes a retract path that is positioned on the upstream side of a stacker section for collecting sheets and that branches off from a transport path to enable a sheet carried in the stacker section to be transported in a direction opposite to a carry-in direction, an adhesion unit that is positioned in a junction position of the transport path and the retract path to bond sheets by applying an adhesive, a staple binding unit that binds sheets collected in the stacker section with a staple, and a folding processing section that folds sheets bound with the unit. The retract path is a path for retracting an application position of the preceding sheet with the adhesive applied, in carrying a next sheet in the stacker section, and the staple binding unit is disposed in the stacker section between the adhesion unit and the folding processing section.

A sheet processing apparatus includes two pressing members and an advancing-receding unit. The pressing members nip and press against a fold section of a sheet. The advancing-receding unit causes the pressing members to repeatedly press against the fold section by causing at least one of the pressing members to advance to and recede from the other pressing member. The advancing-receding unit varies a reception separation amount and a post-receding separation amount from each other and sets the post-receding separation amount to be smaller than the reception separation amount. The reception separation amount is a separation amount by which the pressing members are separated from each other when the fold section is to be received between the pressing members. The post-receding separation amount is a separation amount by which the pressing members that have pressed against the fold section are separated from each other after receding from the fold section.

A sheet processing apparatus includes two pressing members and an advancing-receding unit. The pressing members nip and press against a fold section of a sheet. The advancing-receding unit causes the pressing members to repeatedly press against the fold section by causing at least one of the pressing members to advance to and recede from the other pressing member. The advancing-receding unit varies a reception separation amount and a post-receding separation amount from each other and sets the post-receding separation amount to be smaller than the reception separation amount. The reception separation amount is a separation amount by which the pressing members are separated from each other when the fold section is to be received between the pressing members. The post-receding separation amount is a separation amount by which the pressing members that have pressed against the fold section are separated from each other after receding from the fold section.

A sheet processing apparatus includes a sheet holding unit, a sheet conveying unit configured to convey a plurality of sheets one by one onto the sheet holding unit during sheet processing, wherein the plurality of sheets including a first sheet and a second sheet that is conveyed immediately after the first sheet and is a last of the plurality of sheets that is conveyed, an adhesive applying unit configured to apply an adhesive material, and a control unit configured to control the adhesive material applying unit to apply the adhesive material on the first sheet held on the sheet holding unit before the second sheet is conveyed onto the first sheet and cause the adhesive material applying unit to not apply the adhesive material on the second sheet after the second sheet is conveyed onto the first sheet.

A sheet processing apparatus includes a sheet holding unit, a sheet conveying unit configured to convey a plurality of sheets one by one onto the sheet holding unit during sheet processing, wherein the plurality of sheets including a first sheet and a second sheet that is conveyed immediately after the first sheet and is a last of the plurality of sheets that is conveyed, an adhesive applying unit configured to apply an adhesive material, and a control unit configured to control the adhesive material applying unit to apply the adhesive material on the first sheet held on the sheet holding unit before the second sheet is conveyed onto the first sheet and cause the adhesive material applying unit to not apply the adhesive material on the second sheet after the second sheet is conveyed onto the first sheet.

The present sheet processing apparatus is to obtain that folding in the center portion in the width direction of sheets is made, folding in the end portion is made more reliably by repeatedly pressing the end portion in the width direction, the folded sheets are harder to open, the appearance is also enhanced, and that collection characteristics are improved in stacking bunches of folded sheets, a sheet processing apparatus is provided with pairs of press members (press rollers 70) that press a folded loop BL of folding sheets BS, and a support unit 56 that shifts in the width direction of the folding sheets, while supporting a plurality of rows with a distance between the press members narrowed stepwise in the shift direction.

The present sheet processing apparatus is to obtain that folding in the center portion in the width direction of sheets is made, folding in the end portion is made more reliably by repeatedly pressing the end portion in the width direction, the folded sheets are harder to open, the appearance is also enhanced, and that collection characteristics are improved in stacking bunches of folded sheets, a sheet processing apparatus is provided with pairs of press members (press rollers 70) that press a folded loop BL of folding sheets BS, and a support unit 56 that shifts in the width direction of the folding sheets, while supporting a plurality of rows with a distance between the press members narrowed stepwise in the shift direction.

A folding machine for folding a stack of sheets, the folding machine comprising: a frame; mechanism for pre-folding a stack of sheets along a crease line into a main plane such that a booklet with a straight back is obtained; mechanism for keeping the pre-folded booklet relative to the frame; mechanism for finishing the fold; and a transport plate having a leading edge around which the stack of sheets is folded, the transport plate being movable along the mechanism for pre-folding and the mechanism for finishing the fold.

A folding machine for folding a stack of sheets, the folding machine comprising: a frame; mechanism for pre-folding a stack of sheets along a crease line into a main plane such that a booklet with a straight back is obtained; mechanism for keeping the pre-folded booklet relative to the frame; mechanism for finishing the fold; and a transport plate having a leading edge around which the stack of sheets is folded, the transport plate being movable along the mechanism for pre-folding and the mechanism for finishing the fold.

In a saddle-stitching apparatus, when a sheet is transported to a center-folding unit, a folding blade moves from a retrieved position to a nip position between a pair of folding rollers. A forward end of the folding blade comes into contact with a fold of the sheet, so that the sheet is folded along the fold. When the sheet is attached to the nip position between the folding rollers, the folding rollers start rotating and then, the folding blade inserts the center-folded sheet between the folding rollers. After the center-fold finishing is completed, the rotations of the folding rollers stop in timing at which the folding blade is pulled out of the nip position between the folding rollers. When pulling the folding blade out of the nip position between the folding rollers, the rotations of the folding rollers restart.