A binding apparatus includes: a first toothed part including teeth arranged in one direction; and a second toothed part that includes teeth arranged in the one direction and is configured to mesh with the first toothed part and to press a bundle of sheets, wherein at least one first groove is formed between adjacent teeth of the first toothed part, the first groove has cross-sectional areas at central and end portions in a direction orthogonal to the one direction and a direction in which the first and second toothed parts mesh with each other, the one direction and the orthogonal direction are normal to the cross-sectional areas, and the cross-sectional area at the end portion is larger than the cross-sectional area at the central portion.

A binding device includes a pressing member that has a first tooth, which forms unevenness in a recording material bundle, and a second tooth, which is paired with the first tooth and forms unevenness in the recording material bundle, and presses the recording material bundle with the recording material bundle sandwiched between the first tooth and the second tooth and a control unit that performs control such that pressing is released after a timing when a load on the pressing member decreases from start of pressing of the recording material bundle by the pressing member.

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 recording material processing apparatus includes first teeth that are used for binding processing of a recording material bundle; second teeth that move along a linear route toward the first teeth and presses the recording material bundle located between the first teeth and the second teeth; and a guide portion that is disposed along the linear route and guides the second teeth moving toward the first teeth.

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 apparatus includes a binding tool, a binding tool driver, a shaft, and control circuitry. The binding tool is configured to execute a first binding process at a first binding position on a sheet bundle and execute a second binding process at a second binding position different from the first binding position on the sheet bundle. The binding tool driver includes a driver and is configured to apply a driving force to move the binding tool and a driving force to execute the first binding process and the second binding process. The shaft is disposed between the binding tool and the binding tool driver to support a movement of the binding tool by application of the driving force to the first binding position and the second binding position.

A post-processing apparatus includes a binding tool configured to bind a sheet bundle, a binding tool driver, and control circuitry. The binding tool driver is configured to apply a driving force to move the binding tool to a first binding position at which the binding tool executes a first binding process on the sheet bundle and a second binding position different from the first binding position. At the second binding position, the binding tool executes a second binding process on the sheet bundle. The control circuitry is configured to cause the binding tool driver to move the binding tool to the first binding position at a first movement speed to execute the first binding process, and move the binding tool from the first binding position to the second binding position at a second movement speed slower than the first movement speed to execute the second binding process.

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.

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.