A binding apparatus includes: a first pressing part that presses a recording material bundle; a second pressing part that faces the first pressing part and presses the recording material bundle; and a moving mechanism that swings at least one of the first pressing part and the second pressing part in a pressing direction to press the recording material bundle and causes the at least one of the first pressing part and the second pressing part to move further with respect to a pressing area of the recording material bundle in an entering and exiting direction where a recoding material or the recoding material bundle enters and exits the pressing area.

A binding unit includes a first pressing part that presses a recording material bundle to bind the recording material bundle, a second pressing part that faces the first pressing part, and a pushout part that pushes out the second pressing part toward the first pressing part by acting on the second pressing part using an upper shaft lever and by varying a distance from a start portion serving as a start point of pushout movement to the upper shaft lever. The start portion is formed integrally with a member at which the first pressing part is formed.

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 stapleless binding device includes a stapleless binding unit that performs a stapleless binding operation to form irregularities in a sheet stack by making forward and backward movements, a moving unit that relatively moves the stapleless binding unit or the sheet stack in a direction along one side of the sheet stack, and a holding unit that holds the sheet stack during the backward movement of the stapleless binding unit. The holding unit holds the sheet stack during the backward movement of the stapleless binding unit before the moving unit moves the stapleless binding unit or the sheet stack.

A recording-medium binding device includes a first tooth row and a second tooth row. The first tooth row and the second tooth row to be engaged with the first tooth row cooperate with each other to pinch a recording medium batch. The first tooth row and the second tooth row include at least one first region and at least one second region adjacent to the at least one first region. When the first tooth row and the second tooth row are engaged with each other, teeth of the first tooth row and teeth of the second tooth row overlap one another in a tooth height direction by a first engagement overlapping amount in the at least one first region and by a second engagement overlapping amount in the at least one second region. The second engagement overlapping amount is larger than the first engagement overlapping amount.

A sheet binding device includes a sheet shifting unit, a tape cutter, and a tape attachment unit. The sheet shifting unit has a guide and is configured to stack multiple sheets on the guide with edge portions that are shifted from each other to form a sheet bundle. The tape cutter cuts tape with a target length that is varied in accordance with a thickness of the sheet bundle. The tape attachment unit is configured to attach the cut tape having the target length to an edge portion of the sheet bundle.

A recording-medium binding device includes a first tooth row including plural teeth and a second tooth row including plural teeth. The first and second tooth rows include a central region and end regions. The plural teeth of each of the first and second tooth rows include at least one tooth disposed in the central region and at least one tooth dispose in each of the end regions. In a process of pinching the recording medium batch, the at least one tooth of the first tooth row in the end region and the at least one tooth of the second tooth row in the end region pinch the recording medium batch earlier than the at least one tooth of the first tooth row in the central region and the at least one tooth of the second tooth row in the central region.

A binding device includes a first pressing member that presses a recording-medium stack from one surface side of the recording-medium stack, a second pressing member disposed at a position opposed to the first pressing member to press the recording-medium stack from the other surface side of the recording-medium stack, and a reduction part provided in at least one pressing member of the first pressing member and the second pressing member to reduce creases in recording media of the recording-medium stack in a binding operation when a number of the recording media in the recording-medium stack is smaller than a maximum number of recording media to be bound by the first pressing member and the second pressing member.

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 some of parts of inclined surfaces of the toothed part which form the recesses, second curved surfaces having the centers of curvature on the opposite sides of the inclined surfaces to the centers of curvature of first curved surfaces which form the recesses are formed.