In a sheet postprocessing apparatus, an accommodation paddle increases a rate of increase in transport force generated for sheets by the accommodation paddle, in conjunction with a rate of increase in transport resistance generated for the sheets by a sheet pressing member with an increase in number of the sheets stacked on a sheet stacker.

A stapling apparatus including a holding portion that receives and holds a plurality of mediums, a first matching portion positioned downstream of the holding portion, a paddle that applies sending force to the mediums so that leading edge sides of the mediums reach the first matching portion, a stapler that binds the mediums, the leading edge sides of the mediums having been matched by the first matching portion, a folding mechanism portion that folds the mediums that have been bound by the stapler. In the stapling apparatus, the first matching portion is configured to move and is configured to transport the mediums to a performing position of the stapler and a performing position of the folding mechanism portion by moving, and a position where the paddle applies sending force to the mediums differs according to lengths of the mediums in a transport direction.

According to embodiments, a sheet post-processing apparatus includes a processing tray, a vertical alignment section, a horizontal alignment section and a controller. The controller is configured to control the horizontal alignment section to shift the sheet to a first alignment position a predetermined distance from the center of the processing tray in the sheet width direction, control the horizontal alignment section to align the sheet in the sheet width direction at the first alignment position, and control the vertical alignment section to align the sheet in the conveying direction at the first alignment position, control the horizontal alignment section to realign the sheet at the first alignment position.

A post-processing device includes a transport path along which a medium printed with liquid ejected by a liquid ejecting portion is transported, an intermediate tray on which the medium is stacked, a first transporting member starting a first transporting operation of transporting the medium upstream in a transport direction after a rear end of the medium passes through the transport path, a rear-end alignment portion that comes into contact with the rear end of the medium transported by the first transporting member and that aligns the medium, a control portion controlling an operation of the first transporting member, and a detection portion detecting a transporting state of the medium in the intermediate tray, in which when the control portion determines, from an output of the detection portion, that the medium reaches the rear-end alignment portion, the control portion regulates the first transporting operation of the first transporting member.

According to an example, printed media stack alignment may include actuating a belt and a paddle to shift first and second sheets to a stopper position represented by register of the first and second sheets against a stopper. The stopper may be actuated to shift the first and second sheets to an eject position, where the eject position is intermediate to a sheet deposit position and the stopper position. The belt and the paddle may be actuated to shift the first sheet, the second sheet, and a third sheet received at the sheet deposit position to the stopper position. The stopper may be actuated to shift the first, second, and third sheets to the eject position. Further, an ejector may be actuated to eject a stack including the first, second, and third sheets from the eject position.

A paddle device for a finisher device to align paper discharged from an imaging apparatus comprises a paddle drive shaft to be rotated by a paddle motor, a rotation body having an installation hole, through which the paddle drive shaft is fitted into the rotation body, and a paddle blade extending from the rotation body and having an end portion that is to contact the paper while the paddle drive shaft is rotated by the paddle drive shaft, to align the paper.

An paddle apparatus for a finisher includes a rotatable shaft and a paddle coupled to the rotatable shaft. The paddle is rotatable in a forward direction to compile a recording medium toward an end of a register tray of the finisher, and is rotatable in a reverse direction to apply a downward force to the compiled recording medium. An amount that the paddle is rotated in the reverse direction can be varied based on a height of the compiled recording medium in the register tray.

An image forming apparatus is provided. The image forming apparatus includes a printing engine, a paddle device, a stapler device, and a processor. The printing engine is to form an image on a printing paper. The paddle device is to move the printing paper ejected from the printing engine in a moving direction to align a first end of the printing paper. The stapler device is to staple the align printing paper. The processor is to control the paddle device and the stapler device to move a second end of the aligned printing paper in an opposite direction to the moving direction when the first end of the printing paper is aligned.

A tray unit assembly includes a housing, a separating/stacking unit, a tray unit and an elevating member. The separating/stacking unit includes a separating roller unit and a stacking roller unit provided in the housing. The tray unit is provided to be inserted into the housing and includes a first tray body fixed to the housing when the tray unit is inserted into the housing, and a second tray body connected to the first tray body to be slidable in a vertical direction and having a media stacking space formed therein. The elevating member is disposed to be movable up and down and configured to be in contact with a bottom surface of the second tray body to move the second tray body toward the stacking roller unit or the separating roller unit.

A medium stacking sheet is installed on a rotation shaft of a medium separating and stacking apparatus for stacking or dispensing a medium. The medium stacking sheet includes a body fixed to the rotation shaft and having a plurality of rotation holes which are spaced apart from each other in a rotation direction of the rotation shaft, and a plurality of vanes each including a vane pin rotatably installed in a corresponding rotation hole and a vane piece coupled to the vane pin to stack the medium.