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 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 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 binding processing apparatus includes a binding device which performs a binding process on a sheet bundle stacked on a stacking unit and a sheet bundle set at a manual setting portion, the stacking unit stacking introduced sheets, a sheet bundle being set to the manual setting portion from an outside; a moving portion which moves the binding device to a first binding position for performing the binding process on a sheet bundle stacked on the stacking unit and a second binding position for performing the binding process on a sheet bundle set at the manual setting portion; and a controller which causes the binding device, in a case that the binding process is not performed on a sheet bundle stacked on the stacking unit, to wait due to the moving portion at a position different from the first binding position.

A sheet binding processing apparatus includes a binding device which performs a binding process on a sheet bundle stacked on a stacking unit and a sheet bundle set at a manual setting portion, the stacking unit stacking introduced sheets, a sheet bundle being set to the manual setting portion from an outside; a moving portion which moves the binding device to a first binding position for performing the binding process on a sheet bundle stacked on the stacking unit and a second binding position for performing the binding process on a sheet bundle set at the manual setting portion; and a controller which causes the binding device, in a case that the binding process is not performed on a sheet bundle stacked on the stacking unit, to wait due to the moving portion at a position different from the first binding position.

A pair of tooth portions has a plurality of convex portions and is arranged to engage with each other when approaching each other. The convex portion of at least one tooth portion of the pair of tooth portions has, on an opposing surface thereof opposing the convex portion of the other tooth portion, an abutting surface abutting against the convex portion of the other tooth portion when the pair of tooth portions is engaged with each other and a non-abutting surface not abutting against the convex portion of the other tooth portion when the pair of tooth portions is engaged with each other.

A pair of tooth portions has a plurality of convex portions and is arranged to engage with each other when approaching each other. The convex portion of at least one tooth portion of the pair of tooth portions has, on an opposing surface thereof opposing the convex portion of the other tooth portion, an abutting surface abutting against the convex portion of the other tooth portion when the pair of tooth portions is engaged with each other and a non-abutting surface not abutting against the convex portion of the other tooth portion when the pair of tooth portions is engaged with each other.