A binding processing apparatus includes: a pressure-applying member pair that has multiple projections arranged side-by-side and applies pressure to a sheet stack by pressing the projections against the sheet stack; and an advancing-and-retracting part that causes at least one of the pressure-applying members in the pressure-applying member pair to move toward or away from the other pressure-applying member. A pitch of the projections in each pressure-applying member is from 1.2 mm to 1.5 mm, and a height of the projections is from 0.55 mm to 0.75 mm, and a load per unit area applied from each pressure-applying member to the sheet stack when the pressure-applying member applies pressure to the sheet stack is from 42 N/mm.sup.2 to 94 N/mm.sup.2.

To provide a sheet binding processing apparatus for enabling strong binding strength or weak binding strength to be selected in a neat sheet posture to perform binding processing in applying narrow pressure to a plurality of sheets with concavo-convex-shaped pressurizing surfaces to perform the binding processing, in positioning sheets in a binding position for press-binding the sheets with the concavo-convex-shaped pressurizing surfaces that mutually mesh to perform the binding processing, it is possible to set an engagement area of the sheets and the pressurizing surfaces in two or more different steps with positioning references or by shifting a position of a binding processing section in the direction for passing over an edge side of the sheets to perform the binding processing.

A staple-less binding unit including a pair of upper and lower teeth binds a sheet bundle which is discharged to an intermediate processing tray by a sheet discharge portion and whose one edge abuts against a rear edge stopper. A control portion switches a binding mode of the staple-less binding unit that implements the binding process on the sheet bundle in a first binding mode of binding the sheet bundle without any staple such that the pair of upper and lower teeth bite across an edge of the sheet bundle and in a second binding mode of binding the sheet bundle without any staple such that the pair of upper and lower teeth do not bite across any edge of the sheet bundle.

A post-processing device includes a stacking portion on which media are stacked; a staple binding device that binds the media together by using a staple and that is movable between staple binding positions at which the staple binding device binds the media together and a supply position that is in a front section in a width direction of the media and at which staples are suppliable to the staple binding device; and a stapleless binding device that binds the media together without using a staple and that is movable between a stapleless binding position at which the stapleless binding device binds the media together and a retracted position that is in the front section. When the stapleless binding device is moved to the retracted position, the staple binding device and the stapleless binding device do not interfere with each other irrespective of a position of the staple binding device.

A sheet post-processing apparatus includes a binding unit that crimps a predetermined position on a sheet for binding, and a setting unit that sets the number of binding points at which to bind the sheet. The binding unit applies binding to the sheet at different positions as many as the number of binding points set by the setting unit.

A staple-less binding unit including a pair of upper and lower teeth binds a sheet bundle which is discharged to an intermediate processing tray by a sheet discharge portion and whose one edge abuts against a rear edge stopper. A control portion switches a binding mode of the staple-less binding unit that implements the binding process on the sheet bundle in a first binding mode of binding the sheet bundle without any staple such that the pair of upper and lower teeth bite across an edge of the sheet bundle and in a second binding mode of binding the sheet bundle without any staple such that the pair of upper and lower teeth do not bite across any edge of the sheet bundle.

A sheet binding device includes a binding operation unit including a first tooth-shaped member that has plural arrayed teeth, a second tooth-shaped member that has plural arrayed teeth and binds sheets by biting the first tooth-shaped member to clamp the sheets in cooperation with the first tooth-shaped member, and a link structure that opens and closes the first tooth-shaped member and the second tooth-shaped member to perform a binding operation, and two side frames that are arranged to hold the binding operation unit therebetween and to support the binding operation unit on both sides of the binding operation unit.

A sheet binding device includes a pressurizing unit that pressurizes a sheet bundle to bind the sheet bundle, a pressurizing section that is disposed in the pressurizing unit and configured to be moved from a waiting position separated from the sheet bundle to a pressurizing position at which the pressurizing section pressurizes the sheet bundle, a drive motor that actuates the pressurizing unit, and a controller that controls the drive motor such that the pressurizing section is engaged with the sheet bundle at a predetermined setting velocity.

A sheet processing apparatus includes a binding unit configured to perform binding processing by pressing a sheet bundle, a motor configured to drive the binding unit to press the sheet bundle, and a motor control unit configured to set a driving current of the motor and an upper limit value of the driving current, the motor control unit being configured to set the driving current when starting activating the motor in a state where the binding unit is not pressing the sheet bundle to a first value, and set the upper limit value of the driving current in a period in which the binding unit is pressing the sheet bundle to a second value less than or equal to the first value.

The present invention is to provide a sheet processing device including: a receiving tray capable of accommodating therein a sheet having, at a part thereof, a protruding portion and a sheet not having the protruding portion in a mixed state; a first binding member that binds the accommodated sheet bundle at a substantially center thereof in a sheet conveying direction; a folding section that folds the sheet bundle bound by the first binding member in two; and a second binding member that binds protruding portions of the sheet bundle folded by the folding section on a fore edge side of the sheet bundle. With this configuration, the fore edge side of the folded and saddle-stitched sheet bundle can be bound by temporary binding. Thus, a sheet processing device capable of ensuring the security of a saddle-stitched sheet bundle can be provided.