A post-processing apparatus includes: a first binding unit that binds sheets and moves while rotating a first gear; a second binding unit that binds sheets and moves while rotating a second gear; a common path that is a path along which the first binding unit and the second binding unit move; a first rack gear that is provided along the common path and meshes with the first gear; and a second rack gear that is provided along the common path at a side opposite to the first rack gear with the common path interposed between the second rack gear and the first rack gear, and meshes with the second gear.

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.

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.

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 sheet binding unit includes a first sheet binder having first and second dentate uneven sheet binding elements to conduct a first sheet binding process by engaging each other by a prescribed meshing depth while sandwiching the sheet bundle therebetween to form a dentate unevenness on the sheet bundle at a first sheet binding portion of the sheet bundle, and a second sheet binder having third and fourth dentate uneven sheet binding elements to conduct a second sheet binding process by engaging each other by a greater meshing depth than that made by first and second dentate uneven sheet binding elements of the first sheet binder while sandwiching the sheet bundle therebetween to form a dentate unevenness on the sheet bundle at a second sheet binding portion different from the first sheet binding portion of the sheet bundle.

A sheet binding unit includes a first sheet binder having first and second dentate uneven sheet binding elements to conduct a first sheet binding process by engaging each other by a prescribed meshing depth while sandwiching the sheet bundle therebetween to form a dentate unevenness on the sheet bundle at a first sheet binding portion of the sheet bundle, and a second sheet binder having third and fourth dentate uneven sheet binding elements to conduct a second sheet binding process by engaging each other by a greater meshing depth than that made by first and second dentate uneven sheet binding elements of the first sheet binder while sandwiching the sheet bundle therebetween to form a dentate unevenness on the sheet bundle at a second sheet binding portion different from the first sheet binding portion of the sheet bundle.

There is provided a binding member. The binding member includes: an upper toothed part having projections and recesses for forming irregularities in a bundle of recording materials; and a lower toothed part having projections and recesses for forming irregularities in the bundle of recording materials and forming a pair with the upper toothed part. In at least one of the upper toothed part and the lower toothed part, in side surfaces of the recesses of one toothed part, when the upper toothed part and the lower toothed part are engaged, surfaces wide in a direction parallel to the pressing direction of the toothed parts are formed so as to be provided gaps between the upper toothed part and the lower toothed part.

There is provided a binding member. The binding member includes: an upper toothed part having projections and recesses for forming irregularities in a bundle of recording materials; and a lower toothed part having projections and recesses for forming irregularities in the bundle of recording materials and forming a pair with the upper toothed part. In at least one of the upper toothed part and the lower toothed part, in side surfaces of the recesses of one toothed part, when the upper toothed part and the lower toothed part are engaged, surfaces wide in a direction parallel to the pressing direction of the toothed parts are formed so as to be provided gaps between the upper toothed part and the lower toothed part.

A sheet processing apparatus includes a folding device to fold a sheet and a fold-enhancing device to press a folded portion of the sheet folded by the folding device to perform enhanced folding processing on the sheet whose trailing edge has exited the folding device.

A sheet processing apparatus includes a folding device to fold a sheet and a fold-enhancing device to press a folded portion of the sheet folded by the folding device to perform enhanced folding processing on the sheet whose trailing edge has exited the folding device.