According to one embodiment, a sheet post-processing apparatus includes: a standby unit configured to put a sheet on standby, the standby unit including a tray member on which the sheet is placed; a corrugation forming unit configured to form a corrugation in a direction orthogonal to a conveying direction on the sheet in the standby unit, the corrugation forming unit integrally provided with the tray member; and a processing unit disposed below the standby unit and configured to process the sheet supplied from the standby unit, wherein the corrugation forming unit includes: a projecting roller projecting upward from a conveyance reference plane in the standby unit; and a housing unit configured as a part of the tray member to house the projecting roller below the conveyance reference plane.

A binding processing apparatus includes a pair of pressing members each including a concave-convex portion configured to form a concave part and a convex part in a recording material bundle. The concave-convex portion includes protrusion portions. Aside surface of each protrusion portion is inclined so that the protrusion portion is widened from an apex of the protrusion portion. The side surfaces of the protrusion portions of a first pressing member that is one of the pressing members and the side surfaces of the protrusion portions of a second pressing member that is the other of the pressing members intersect with each other during pressing when viewed in a column direction of the protrusion portions.

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.

A binding device includes a first pushing member that includes protrusions along one direction and that pushes a recording-material bundle as a result of pushing the protrusions against one of surfaces of the recording-material bundle, the protrusions disposed side by side in a direction that intersects the one direction; and a second pushing member that includes protrusions along the one direction and that pushes the recording-material bundle as a result of pushing the protrusions against the other surface of the recording-material bundle, the protrusions disposed side by side in the direction that intersects the one direction, wherein, in at least one end portion in the one direction of each protrusion of at least one of the first pushing member and the second pushing member, a hollow is disposed in a top portion of each protrusion.

A binding member is provided and includes: upper teeth having a tooth form configured to form a convex-concave portion on a recording material bundle; and lower teeth having a tooth form configured to form the convex-concave portion on the recording material bundle, and paired with the upper teeth. At least one of the upper teeth and the lower teeth includes: a first tooth row having a first tooth form having a first shape suitable for binding a first binding number of sheets; and a second tooth row having a second tooth form having a second shape suitable for binding a second binding number of sheets which is smaller than the first binding number of sheets.

A series of conveyance paths to convey a recording medium is formed across a printer and a post-processing device in a printing system. The printing system includes: a detection unit that detects that the post-processing device has entered a predetermined state; and a paper feeding control unit that limits the number of recording media fed to the conveyance path, when it is not detected that the post-processing device has entered the predetermined state, based on the number of recording media conveyable to the post-processing device after the post-processing device enters the predetermined state.

A staple-less binding unit is provided with upper and lower die portions having pluralities of concave and convex teeth engaging with each other. A control portion causes the staple-less binding unit to carry out a binding process of binding a sheet bundle by biting the sheet bundle by the upper and lower die portions and to carry out a cleaning process of engaging the upper and lower die portions in a non-binding process in which no binding process is carried out.

A sheet stacking apparatus including a control portion is configured to execute: a first mode in which the control portion causes a bundle forming portion to form a bundle of sheets including a sheet supported by a first placement portion and a sheet placed on a second placement portion; and a second mode in which a downstream end portion of a bundle of sheets formed in the second mode is positioned upstream of a downstream end portion of a bundle of sheets to be formed in the first mode, and wherein the control portion sets a maximum number of sheets constituting a bundle of sheets which the control portion causes the bundle forming portion to form in the second mode to be smaller than a maximum number of sheets constituting a bundle of sheets which the control portion causes the bundle forming portion to form in the first mode.

A sheet conveying device has a body and a frame supporting it, and is insertable or extractable along a sheet stacking face formed in an in-body discharge space in an image forming apparatus and having an inclined face with an upward gradient toward the downstream side in the sheet discharge direction. On the face of the frame opposite the sheet stacking face, a plurality of first and second wheels rotatable in the insertion or extraction direction are provided downward of the center of the opposite face in the insertion direction. The first wheels are arranged downstream of the second wheels in the insertion direction, and protrude from the opposite face farther than the second wheels. The first wheels fit into a concave portion formed in the sheet stacking face by the inclined face and thereby enable the second wheels to make contact with the sheet stacking face.

Provided is a sheet processing apparatus, including: a regulation portion configured to contact with an end edge of a sheet to be conveyed and to regulate a position of the sheet; a position adjustment portion configured to perform position adjustment on a sheet in a direction along an end edge of the sheet of which the end edge is in contact with the regulation portion; a folding portion configured to perform folding processing on a sheet which has been regulated by the regulation portion; and a control portion configured to execute: a first mode of causing the folding portion to perform the folding processing on a sheet which has been regulated by the regulation portion, without causing the position adjustment portion to perform the position adjustment on the sheet; and a second mode of causing the position adjustment portion to perform the position adjustment with respect to the regulated sheet.