A sheet stacker includes a housing, a fence, a first distance measurement sensor, and a second distance measurement sensor. The fence is movable in a fence moving direction on the housing and is configured to regulate a position of an end of a sheet. The first distance measurement sensor is configured to measure a distance between the fence and a first portion of the housing, the first portion being on one side of the housing with respect to the fence in the fence moving direction. The second distance measurement sensor is configured to measure a distance between the fence and a second portion of the housing, the second portion being on another side of the housing with respect to the fence in the fence moving direction.

A sheet stacker includes a housing, a fence, a first distance measurement sensor, and a second distance measurement sensor. The fence is movable in a fence moving direction on the housing and is configured to regulate a position of an end of a sheet. The first distance measurement sensor is configured to measure a distance between the fence and a first portion of the housing, the first portion being on one side of the housing with respect to the fence in the fence moving direction. The second distance measurement sensor is configured to measure a distance between the fence and a second portion of the housing, the second portion being on another side of the housing with respect to the fence in the fence moving direction.

Examples of alignment fins for output trays of media dispensing devices are disclosed. In an example, an alignment fin is coupled to a support surface of an output tray of a media dispensing device. The alignment fin is to transition between a first position wherein the alignment fin is disposed below the support surface, and a second position wherein the alignment fin is exposed through an aperture in the support surface. When the alignment fin is in the second position, the alignment fin is to align the media dispensed from the dispensing device into a stack on the support surface.

Examples of alignment fins for output trays of media dispensing devices are disclosed. In an example, an alignment fin is coupled to a support surface of an output tray of a media dispensing device. The alignment fin is to transition between a first position wherein the alignment fin is disposed below the support surface, and a second position wherein the alignment fin is exposed through an aperture in the support surface. When the alignment fin is in the second position, the alignment fin is to align the media dispensed from the dispensing device into a stack on the support surface.

A medium ejection apparatus includes a placement mount on which media are placed, a restriction part that moves between a restriction position at which the restriction part restricts media ejected toward the placement mount and a retracted position retracted from the restriction position, and a processor that controls the restriction part by adjusting a restriction frequency on the basis of at least either an amount of movement of the restriction part from the retracted position to the restriction position or ejection intervals at which the media are ejected toward the placement mount, the restriction frequency being a frequency with which the restriction part performs a restriction operation for the media.

A medium ejection apparatus includes a placement mount on which media are placed, a restriction part that moves between a restriction position at which the restriction part restricts media ejected toward the placement mount and a retracted position retracted from the restriction position, and a processor that controls the restriction part by adjusting a restriction frequency on the basis of at least either an amount of movement of the restriction part from the retracted position to the restriction position or ejection intervals at which the media are ejected toward the placement mount, the restriction frequency being a frequency with which the restriction part performs a restriction operation for the media.

A post-processing apparatus includes a binding device, a closing device, a driver, and a changeover switch. The binding device binds a sheet bundle. The closing device closes an entrance to a binding position at which the binding device binds the sheet bundle. The driver moves the closing device to a closing position to close the entrance. The switch performs switching to implement a state in which the binding device is able to bind the sheet bundle when the closing device moves to the closing position. The closing device includes an avoidance operation portion to move to the closing position to operate the switch, and a drive coupler coupled to the avoidance operation portion to move the avoidance operation portion to the closing position. A coupling state between the avoidance operation portion and the drive coupler is released when movement of the avoidance operation portion to the closing position is prevented.

A post-processing apparatus includes a binding device, a closing device, a driver, and a changeover switch. The binding device binds a sheet bundle. The closing device closes an entrance to a binding position at which the binding device binds the sheet bundle. The driver moves the closing device to a closing position to close the entrance. The switch performs switching to implement a state in which the binding device is able to bind the sheet bundle when the closing device moves to the closing position. The closing device includes an avoidance operation portion to move to the closing position to operate the switch, and a drive coupler coupled to the avoidance operation portion to move the avoidance operation portion to the closing position. A coupling state between the avoidance operation portion and the drive coupler is released when movement of the avoidance operation portion to the closing position is prevented.

A sheet post-processing apparatus includes an output tray on which a sheet ejected from a sheet outlet is stacked; a wall disposed downstream from the output tray in a sheet ejection direction; and an alignment member configured to contact and move the sheet on the output tray, to bring a rear end of the sheet in the sheet ejection direction into contact with the wall for alignment. The alignment member is selectively set at three positions of: an alignment position protruding beyond the wall toward the output tray to contact the sheet on the output tray; a withdrawn position inward of the wall; and a home position between the alignment position and the withdrawn position.

A sheet post-processing apparatus includes an output tray on which a sheet ejected from a sheet outlet is stacked; a wall disposed downstream from the output tray in a sheet ejection direction; and an alignment member configured to contact and move the sheet on the output tray, to bring a rear end of the sheet in the sheet ejection direction into contact with the wall for alignment. The alignment member is selectively set at three positions of: an alignment position protruding beyond the wall toward the output tray to contact the sheet on the output tray; a withdrawn position inward of the wall; and a home position between the alignment position and the withdrawn position.