A sheet post-processing device includes: an alignment member which aligns a sheet bundle on a stacking tray; and a stapler which performs binding processing on a rear end of the sheet bundle. The stapler includes: a first stapler which moves along the rear end of a first sheet bundle and performs the binding processing on a plurality of positions at the rear end of the first sheet bundle; and a second stapler which performs, at one part of an end portion of the rear end on one side, binding processing different from the first stapler. The alignment member includes: a first alignment member and a second alignment member which align the sheet bundle in a first stacking position; and a third alignment member which is fixed to a position corresponding to the second stapler and which aligns the sheet bundle in a second stacking position with the first alignment member.

A binding apparatus includes a pair of pressing members to sandwich and press a sheet bundle to bind the sheet bundle, a rotator to rotate to periodically separate and contact the pressing members with each other, a detector to detect whether the rotator is between a first position at which the pressing members are separated from each other and a second position downstream from the first position in a forward rotation direction of the rotator, and control circuitry. The second position is upstream in the forward rotation direction from a peak position at which a pressing force between the pressing members is maximum. The control circuitry is configured to rotate the rotator in a reverse direction to the forward rotation direction to move the rotator to the first position when the detector detects that the rotator is between the first position and the second position in the forward rotation direction.

To enable a bunch of sheets to be reliably discharged to a stack tray, also in the case where weight of the bunch of sheets formed on a processing tray is large, upon receiving a printing command, a main body control section checks information on an ink discharge amount in printing on a sheet, the number of sheets, sheet type and printing mode (two-side/one-side). By this means, the section recognizes weight of the bunch of sheets formed on the processing tray, and when determining that the weight is heavier than predetermined weight, deceases an upper limit value of the number of sheets of a bunch of sheets formed at a time to report to a user.

A sheet processing apparatus for performing binding processing for a sheet bundle formed from a plurality of sheets, comprises: an application unit configured to apply a liquid to a sheet wherein the application unit applies the liquid to an outermost sheet of the sheet bundle, and a static surface tension of the liquid is lower than a static surface tension of water; and a binding processing unit configured to bind the sheet bundle, without using a staple, wherein the binding processing unit includes a pair of groups of pressurizing teeth, and the pressurizing teeth clamp and pressurize the sheet bundle. In the sheet bundle, a liquid application region which is applied with the liquid and a pressurizing region which is pressurized by the pressurizing teeth are provided to overlap each other.

A binding device includes a stacking device configured to receive sheets, a sheet alignment member configured to align the sheets on the stacking device, a binder configured to bind the sheets on the stacking device, a binder moving device configured to move the binder, and a retreat device configured to retreat the sheet alignment member from a range of movement of the binder. The retreat device retreats the sheet alignment member in response to a pressing force acting on the sheet alignment member in a direction of movement of the binder.

A sheet processing device includes a stapling unit that cuts off excess parts of a staple at a normal processing position, a container that stores the excess parts, the container having an upper end portion with an opening and being disposed below the stapling unit, a pair of electrodes disposed at a portion of a side wall of the upper end portion, the portion corresponding to the normal processing position, the pair of electrodes being exposed to inside the container, and a control unit for detecting that the excess parts in the container have reached the upper end portion when the pair of electrodes is short-circuited.

A binding apparatus includes: a set of binding parts configured to press and bind a bundle of recording materials from one side and a remaining side in a thickness direction; a first support part configured to support the bundle of recording materials from the one side by performing rotation toward the bundle of recording materials around a predetermined fulcrum; and a second support part configured to support the bundle of recording materials from the remaining side so as to face the first support part when binding is performed by the set of binding parts.

A binding apparatus includes: a first pressing part that presses a recording material bundle; and a second pressing part that is pushed out toward the first pressing part and presses the recording material bundle. When a recording material or the recording material bundle enters a pressing area where the first pressing part and the second pressing part face each other, at least one of the first pressing part and the second pressing part retreats more downstream than the pressing area in a direction where the recording material or the recording material bundle enters the pressing area.

A sheet processing apparatus includes: a conveying unit configured to convey a sheet along a sheet conveyance path; a conveyance-path supporting unit configured to support both ends of the sheet conveyance path with respect to a direction perpendicular to a sheet conveying direction; a first stitching unit configured to stitch the sheets conveyed; a second stitching unit configured to stitch the sheets conveyed; a first moving unit configured to move the first stitching unit in a direction perpendicular to the sheet conveying direction; and a second moving unit configured to move the second stitching unit in a direction perpendicular to the sheet conveying direction, wherein any one of the first stitching unit and the second stitching unit is movable to outside of the conveyance-path supporting unit.

An image forming apparatus includes: a needleless binding device configured to form a recessed or raised impression as a needleless binding part by performing needleless binding on a bundle of sheets; an environment sensor; and a controller configured to perform, based on a value detected by the environment sensor, control to display a confirmation image requesting a user to make confirmation on the needleless binding prior to execution of the needleless binding.