To provide a sheet stacking apparatus and image forming system capable of improving alignment characteristics also in the case where an aligning section is not able to act on a sheet discharged onto a stacking tray, the sheet stacking apparatus and image forming system include a stacking tray stacking discharged sheets, a pair of aligning sections capable of shifting in a width direction to align the width direction crossing a direction in which the sheet to stack on the stacking tray is discharged, and a control section that controls a relative position of the aligning sections and the sheet to discharge so that one of the pair of the aligning sections regulates a shift of the sheet stacked on the stacking tray to one direction side in the width direction, when a sheet with a predetermined width in the width direction of the sheet is discharged to the stacking tray.

To provide a sheet stacking apparatus and image forming system capable of improving alignment characteristics also in the case where an aligning section is not able to act on a sheet discharged onto a stacking tray, the sheet stacking apparatus and image forming system include a stacking tray stacking discharged sheets, a pair of aligning sections capable of shifting in a width direction to align the width direction crossing a direction in which the sheet to stack on the stacking tray is discharged, and a control section that controls a relative position of the aligning sections and the sheet to discharge so that one of the pair of the aligning sections regulates a shift of the sheet stacked on the stacking tray to one direction side in the width direction, when a sheet with a predetermined width in the width direction of the sheet is discharged to the stacking tray.

A sheet post-processing device includes a folding portion, a discharge portion, a stacking tray, a shift unit, a pair of alignment members, and a controller. The pair of alignment members include first and second alignment members at one and the other side of sheets stacked on the stacking tray. When a sheet bundle sorted and stacked on the stacking tray includes a folded sheet, executes a second alignment mode in which it performs, for sheets shifted to a first position at one side on the stacking tray, alignment with only the first alignment member and, for sheets shifted to a second position at the other side, alignment with only the second alignment member, or does not perform alignment process.

A sheet sorting device includes a plurality of trays, a tray shifter, a tray stop position detector, and circuitry. The plurality of trays is disposed in multiple stages in a vertical direction and configured to stack a sheet. The tray shifter is configured to move the plurality of trays separately in a tray shift direction. The tray stop position detector is configured to detect stop positions of the plurality of trays separately. The circuitry is configured to cause the tray shifter to move the plurality of trays to home positions in an initial operation, at least one tray having a home position opposite to a home position of another tray in the tray shift direction. The circuitry is configured to, while moving the plurality of trays at a same time in the initial operation, cause the tray shifter to move the trays in directions opposite to each other.

A postprocessing apparatus includes a horizontal alignment plate, a binder, a tray, and a shift actuator assembly. The horizontal alignment plate is positioned to align sheets in a sheet width direction. The binder binds sheets to form bound sheet bundles. The bound sheet bundles are stacked on the tray. The shift actuator assembly shifts the bound sheet bundles in the sheet width direction. A postprocessing controller controls the shift actuator assembly to shift the bound sheet bundles such that swollen portions of the bound sheet bundles are shifted inward of the horizontal alignment plate in the sheet width direction when the processed sheets are piled on the tray to the vicinity of the horizontal alignment plate.

A sheet processing device includes a stacking member configured to stack a sheet, a discharging member configured to discharge the sheet stacked on the stacking member, a discharging tray on which the sheet discharged by the discharging member is stacked, a pushing-out member configured to push out the sheet from the stacking member toward the discharging member by being moved in a pushing-out direction, and a controller configured to select, on the basis of information of the sheet stacked on the stacking member, whether to move the pushing-out member to which position of a first position and a second position positioned on a side downstream of the first position with respect to the pushing-out direction.

A sheet discharge device includes at least one sheet discharge tray, a sheet discharge position adjustment actuator, and a controller. The sheet discharge tray receives discharged sheets. The discharge position adjustment actuator adjusts discharge positions of the discharged sheets on the at least one sheet discharge tray. The controller compares a first rotation amount of first print data printed on a first sheet with a second rotation amount of second print data printed on a second sheet. In response to a determination that the first rotation amount is different than the second rotation amount, the controller controls the sheet discharge position adjustment actuator to (a) discharge the first sheet to a first discharge position and (b) discharge the second sheet to a second discharge position different than the first discharge position.

A post-processing device includes a loading unit on which a sheet is loaded, a first transport unit configured to apply, to the sheet loaded on the loading unit, a transport force toward an alignment unit, a second transport unit located between the first transport unit and the alignment unit, and configured to apply, to the sheet, a transport force toward the alignment unit, a control unit configured to control rotation operation of the second transport unit, and a post-processing unit configured to perform post-processing on the sheet transported to the alignment unit, wherein the post-processing unit is configured to execute a plurality of types of the post-processing, and the control unit is configured to control the rotation operation of the second transport unit in accordance with the type of the post-processing.

Provided is a sheet stacking apparatus including an aligning member lifting-lowering device configured to lift and lower aligning members between an aligning position where the aligning members abut to and align the sheets and a retreating position where the aligning members are lifted from an upper surface of the sheets, an aligning member moving device configured to move the aligning members in a sheet width direction, and a stack tray lifting-lowering device configured to lift and lower a stack tray based on a detection result of a sheet surface detecting device. A controller lifts the aligning members to the retreating position with the aligning member lifting-lowering device after the sheets stacked on the stack tray is aligned at the aligning position, and stops lifting-lowering operation of the stack tray lifting-lowering device while the aligning members are moved in the sheet width direction with the aligning member moving device.

A sheet conveyance apparatus includes a first conveyance path, a detection portion, a second conveyance path, a discharge unit, and a controller. The discharge unit is movable in a width direction and is configured to perform a discharge operation of discharging a sheet onto a first discharge portion and a reversing operation of reversing and conveying the sheet to the second conveyance path. The controller is configured to control the discharge unit and to execute a first alignment control when the reversing operation is performed. The first alignment control is a control in which the discharge unit moves the sheet in the width direction based on a position of the sheet detected by the detection portion to align the sheet at a target position.