The stacker comprises two stacking platforms and a system for conveying corrugated board sheets, configured to discharge the sheets alternatively onto one or the other of the two stacking platforms. A switching device allows for a quick switch of the conveyor system from one to the other of two operating conditions.

A post-processing device for processing a sheet includes a first post-processing section and a second post-processing section, for processing a sheet; a buffer section for temporarily staying a sheet transferred from a carry-in port; a first conveying section for conveying a sheet at the buffer section to the first post-processing section; and a second conveying section for conveying a sheet at the buffer section to the second post-processing section.

A sheet stacker includes a sheet conveyor arrangement and a stacker platform. The sheets are fed in a sheet feeding direction on the stacker platform, to form stacks of sheets thereon. The stacker platform supports a stack conveyor configured and controlled to move in a conveyor direction to move the stack under formation such that sequentially piled up jobs are placed in an approximately centered position one with respect to the other according to the sheet feeding direction.

A medium processing device includes a discharge member, a discharge tray, a shift part and a control part. The discharge member is configured to discharge a medium from a discharge position in a discharge direction. On the discharge tray, the medium is stacked. The shift part is configured to vary a relative position of the discharge position and the discharge tray in a shift direction perpendicular to the discharge direction to shift a shift position where the medium is stacked on the discharge tray. The control part is configured to control the shift part so as to shift the shift position for each medium bundle containing a plurality of the mediums. The control part calculates a thickness of the medium bundle, and when the calculated thickness exceeds a first threshold value, the control part makes it possible to select a number of the shift position from a plurality of candidates.

The sheet stacker includes a sheet conveyor arrangement, configured for feeding a plurality of sheets and having a sheet discharge end, and a stacking bay. In the stacking bay sheets delivered by the sheet conveyor arrangement are formed into stacks. A stack conveyor is provided in the stacking bay and is movable in a conveyor direction parallel to a sheet feeding direction, according to which the sheets are fed from the sheet discharge end onto the stack conveyor. The sheet discharge end is configured and controlled such that it is gradually lifted during sheet stacking, in order to accommodate a growing stack of sheets being formed on the stack conveyor. A stop plate is positioned in the stacking bay above the stack conveyor and in front of the sheet discharge end of the sheet conveyor arrangement. The stop plate is configured and controlled to be gradually lifted from the stack conveyor as the sheet stack grows, to be withdrawn upon completion of the stack thus allowing removal of the stack in an evacuation direction substantially parallel to the conveyor direction, and to be lowered towards the stack conveyor again.

Disclosed herein is a sheet processing apparatus comprising a sheet tray configured to hold a bundle composed of the sheets fed from conveyance rollers, a wait path configured to keep waiting following sheets upstream the conveyance rollers, an accumulating tray configured to hold a sheet bundle, delivery rollers configured to nip the sheet bundle mounted on the sheet tray and the following sheets, to set off from one another, and to deliver them to the accumulating tray, and to switch back the following sheets to the sheet tray, and a conveyance member configured to convey the following sheets from the sheet tray.

A sheet processing apparatus includes a sheet processing unit that processes a sheet placed on a placing tray, a discharge roller that discharges the sheet processed on the placing tray to a stacking tray, a conveyance roller that discharges a sheet to the placing tray or conveys a subsequent sheet from upstream to downstream of the discharge roller and switchback-conveys the subsequent sheet upstream again, and a standby path (branch path) that keeps the sheet switched back by the conveyance roller on standby. The subsequent sheet is conveyed to a downstream side of the discharge roller by the conveyance roller and then returned to an upstream side again by switchback conveyance. During the switchback conveyance, the discharge roller nips and discharges the sheets on the placing tray to the stacking tray.

A sheet processing apparatus includes an intermediate tray on which a sheet is to be stacked, a stapler to execute stapling processing on the stacked sheet, a discharge tray on which the sheet subjected to the stapling processing by the stapler and discharged from the intermediate tray is to be stacked, a control unit, and a shift unit. The shift unit may shift the sheet to a position on the intermediate tray, wherein the position is outside of a range in which the stapling processing is to be executed. In a state where a first sheet and a second sheet are stacked on the intermediate tray and the second sheet is subject to the stapling processing, the control unit causes the shift unit to shift the first sheet on which the stapling processing is not executed, and causes the stapler to execute the stapling processing on the second sheet.

A post-processing device (200) includes a circulation conveyance path, a zeroth conveyer (R0), and a controller (50). The circulation conveyance path includes a first conveyance path (W1), a second conveyance path (W2), a third conveyance path (W3), a first conveyer (R1), a second conveyer (R2), and a third conveyer (R3). The first and second conveyers convey a preceding sheet (P1) along the first and second conveyance paths. The third conveyer conveys it from the third conveyance path to the first conveyance path. The zeroth conveyer conveys a following sheet (P2) toward the first conveyer. The controller controls the third conveyer to stop the preceding sheet, subsequently controls the zeroth conveyer and the third conveyer to overlay the preceding sheet with the following sheet to form a sheet bundle (Q) having a shift amount (G) between a leading edges of the preceding sheet and the following sheet and strike the leading edges of the preceding sheet and the following sheet against the first conveyer.

A sheet stacker including a sheet conveyor arrangement and a stacking bay, wherein sheets delivered by the sheet conveyor arrangement are formed into stacks; the stacking bay including a stacker platform. The stacker platform is provided with a vertical lifting and lowering movement with respect to a stationary supporting structure and is controlled to move downwards while a stack of sheets is formed thereon. The stacker platform supports a stack conveyor configured and controlled to perform at least an evacuation motion, to remove a completed stack from the stacking bay. The evacuation motion of the stack conveyor is oriented such that a completed stack is moved from the stacking bay onto an evacuation conveyor arranged under the sheet conveyor arrangement.