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 when an end portion of the at least one pressing member is pressed against the recording-medium stack.

A sheet processing apparatus includes a conveying portion, a stack portion on which sheets conveyed by the conveying portion are stacked, a first regulating portion regulating a position of a sheet bundle stacked on the stack portion in a crossing direction, a second regulating portion regulating a position of a sheet bundle on the stack portion in a conveying direction, a first binding device moved in the crossing direction and binding a corner portion of a sheet bundle by a staple, a second binding device binding a corner portion of a sheet bundle without a staple, and a controller positioning the first binding device and binding a corner portion of a sheet bundle by the first binding device. The controller also moves the second binding device and binds a corner portion of a sheet bundle without a staple by the second binding device.

A sheet processing apparatus includes a conveying portion, a first stack portion on which sheets conveyed are stacked, a first regulating portion which regulates a position of a sheet bundle in a crossing direction crossing to the sheet transport direction, a second regulating portion which regulates a position of a sheet bundle in the conveying direction, a first binding portion binding a corner portion of the sheet bundle by a staple, a second binding portion which binds a corner portion of a sheet bundle without a staple, a second stack portion which stacks a sheet bundle discharged from the first stack portion, and a lifting-lowering motor which lifts and lowers the second stack portion. The lifting-lowering motor is located at a downstream, in the conveying direction, of a first binding position where the first binding portion binds a sheet bundle.

A post-processing apparatus comprises a first processing tray on which fed paper is placed; a paper binding section configured to bind a plurality of sheets of paper stacked on the first processing tray into one bundle; a second processing tray which a plurality of paper bundles bound on the first processing tray are sequentially conveyed to and placed on; a paper bundle gluing section configured to coat glue at a given position of the top surface of a first paper bundle placed on the second processing tray before a second paper bundle is placed on the first paper bundle; a pressing section configured to press and bind the first paper bundle with the second paper bundle between which glue is coated; and a control section configured to control the timing for conveying the second paper bundle onto the first paper bundle after the glue is coated.

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 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 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.

A binding apparatus includes a first pressing member including a base part and multiple projections projecting from the base part, the first pressing member presses a recording media stack from one side; and a second pressing member including a base part and multiple projections projecting from the base part, the second pressing member facing the first pressing member and pressing the recording media stack from the other side. At least one of the first and second pressing members has at least one lower projection whose apex in a projecting direction closer to the base part than the apexes of the other projections are, and the lower projection is provided in the first or second pressing member that has more projections than the other, or more lower projections are provided in the first or second pressing member that has more projections than the other.

A binding apparatus includes: a first pressing member that presses a recording-medium stack from one side of the recording-medium stack; a second pressing member that faces the first pressing member and presses the recording-medium stack from the other side of the recording-medium stack; and a suppressing part provided in at least one of the first pressing member and the second pressing member, the suppressing part suppressing damage to recording media that may be caused when a recording-medium stack including a smaller number of sheets than the maximum number of sheets that can be bound is bound with the first pressing member and the second pressing member.