A sheet binding device includes a first binding unit that performs a first binding process of binding a sheet bundle having a first thickness or less without using a staple, and a second binding unit that performs a second binding process of binding the sheet bundle having a second thickness or less exceeding the first thickness using a staple, the first binding process by the first binding device is preferentially executed when the thickness of the sheet bundle is the first thickness or less, and the second binding process by the second binding unit is executed when the thickness of the sheet bundle exceeds the first thickness and is equal to or less than the second thickness.

A sheet stacking device includes a conveyance part and a stopper. The conveyance part includes a tray and a conveyance member. On the tray, sheet stacks are stacked. The conveyance member conveys the sheet stack on the tray. The stopper is located on a downstream side of the tray and prevents the sheet stack from falling from the tray. The stopper has a main plate and an anti-slip member. The main plate is inclined upward. The main plate has a contact face coming into contact with the sheet stack and a bent face bent downward from a downstream side tip end of the contact face. The anti-slip member is provided from a downstream side end portion of the contact face to the bent face. A frictional coefficient between the anti-slip member and the sheet stack is larger than a frictional coefficient between the sheet stack and the contact face.

A sheet folding apparatus including a folding roller, a positioning member, a push member, and a shift member. The folding roller including a pair of rollers to rotatably engage with each other to form a folding nip. The positioning member to support a first end of a printing medium which is fed along a folding path and to arrange the printing medium in an initial folding location. The push member to move to an insertion location to push the printing medium on the folding path into the folding nip, and to move to a retreat location. The shift member, located at an exit of the folding nip, to selectively guide the printing medium to a guide path to return the printing medium having passed through the folding nip to the folding path, the guide path being provided around at least one of the pair of rollers.

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.

A binding machine, includes: an accommodating portion configured to accommodate a wound binding tape; a main handle; and a clincher arm. The accommodating portion includes, with the wound binding tape in an accommodated state, a side wall portion that faces a side surface of the binding tape, and a circumferential portion that is continuous with the side wall portion, faces a front surface of the binding tape, and is provided with an opening for accommodating the binding tape in a part of the circumferential portion.

A sheet post-processing apparatus includes a first stapler and a second stapler having different thicknesses of sheets on which a binding process can be performed. A control unit can perform a manual staple mode. If the first stapler is selected as a stapler for performing the binding process in the manual staple mode, the control unit controls the alignment member moving mechanism to move alignment members to a position defining a first insertion position for guiding the sheets to a first placing position. If the second stapler is selected, the control unit controls the alignment member moving mechanism to move the alignment members to a position defining a second insertion position for guiding the sheets to a second placing position.

A staple-refill 11 is provided with: a casing 12 in which a plurality of sheet-type connected staples 10 are stacked; a staple inserting port 14; a staple discharge port 16; a cover member 15 which covers the sheet-type connected staples 10 in the casing 12 from a side of the staple inserting port 14; and a notch portion 18 formed in the casing 12 and extending from an edge of the staple inserting port 14 in an insertion 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 includes a conveying portion for conveying sheets, a conveying path for sheets, a stack portion for stacking sheets, a first binding portion having a first binding member and moving in a crossing direction crossing to the conveying direction, a first regulating portion which regulates a position of a sheet bundle stacked on the stack portion, a second regulating portion which regulates a position of a sheet bundle stacked on the stack portion, a third regulating portion which regulates a position of a sheet bundle, and a second binding portion which has a second binding member and binds a corner portion of a sheet bundle without a staple. The first binding portion binds a corner portion of a sheet bundle by a staple. The second binding member is located at a downstream of the first binding member in the conveying direction.

A sheet postprocessing device includes a sheet conveying passage, a sheet tray, an inlet guide, a processing device, and a blowing device. Though the sheet conveying passage, a sheet on which an image has been formed is conveyed. The sheet tray is arranged downstream of the sheet conveying passage and has sheets stacked on it. The inlet guide is arranged at the downstream end of the sheet conveying passage and guides a sheet to the sheet tray. The processing device performs predetermined processing on a sheet stacked on the sheet tray. The blowing device blows air, from the upstream side in the sheet conveying direction, between the top face of the top-most sheet in the sheets stacked on the sheet tray and the bottom face of the subsequent sheet sent from the inlet guide into the sheet tray.