A control method for forming an image includes receiving a pending image-forming job, and obtaining pending image-forming data and image-forming configuration information in the pending image-forming job, the image-forming configuration information including total page number corresponding to the pending image-forming job; performing image-forming operation on an image-forming medium according to the pending image-forming data and the image-forming configuration information; under satisfied predetermined conditions, controlling a discharge distance of at least one page of the image-forming medium of the pending image-forming data to be different from a discharge distance of other pages of the image-forming medium, or controlling a discharge distance of at least one page of the image-forming medium of the pending image-forming job to be different from a discharge distance of the image-forming medium of a previous image-forming job.

A processing apparatus comprises: a conveyance part for conveying a sheet; a processing part including a processing member that is installed in a manner of being movable in an intersecting direction of intersecting with a conveyance direction of the conveyance part and that performs predetermined processing at a predetermined position of the sheet under conveyance; a stacker part for accumulating processing articles obtained by the processing of the processing part; and a control part for controlling the stacker part such as to sort a predetermined amount of precedently ejected ones of the processing articles from the subsequent ones of the processing articles among the processing articles ejected to the stacker part by the conveyance part.

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 control portion controls a distance H and/or a shift amount L1 such that a relationship of L<HL+L1 holds, where L is a length of each sheet among the sheet bundle in the conveyance direction, H is a distance from the conveyance roller pair to an end regulation member in the conveyance direction, and L1 is a shift amount between a first sheet among the sheet bundle and a second sheet adjacent the first sheet. The second sheet is conveyed toward the end regulation member by the conveyance roller pair in the state in which the leading edge of the preceding sheet is in contact with the end regulation member.

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 fed from an image forming device to a path carry-in port is guided to a first accumulating section along a straight path or guided to a second accumulating section along a branch path branched from the straight path. A buffer path section is formed so as to make the sheet temporarily stay between a first sheet discharge roller pair disposed on the straight path side of the branch path at a position downstream of a branch portion and a second sheet discharge roller pair disposed in the branch path. The sheet staying in the buffer path section is conveyed to the first accumulating section by rotation of the first and second conveying rollers in one direction and to the second accumulating section by rotation of the first and second conveying rollers in an opposite direction to the one direction.

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.

A sheet processing apparatus includes a stacking portion on which sheets targeted for sheet processing are stacked. In the apparatus, a control unit generates, in a buffer section provided in a conveyance path for conveying sheets to the stacking portion, a sheet bundle in which positions of sheets conveyed on the conveyance path are shifted in sequence to an upstream side in a conveyance direction and overlapped. An alignment unit performs alignment processing in the conveyance direction on the sheet bundle stacked on the stacking portion. A processing unit performs sheet processing on the sheet bundle on which the alignment processing has been performed. The control unit controls shift amounts of the positions of the sheets when the sheets are overlapped in the buffer section in sequence, according to sizes of the sheets conveyed on the conveyance path.

A post-processing apparatus includes a conveyance path, a buffer unit, a post-processing unit, and a processor. The conveyance path receives a sheet conveyed from a conveyance apparatus in a stage preceding the post-processing apparatus. The buffer unit forms a sheet bundle constituted by sheets. The post-processing unit loads the sheet bundle performs post-processing on the sheet bundle. The processor controls conveyance of the sheets and the sheet bundle and obtains, in a case of a delay amount, a delay amount of the sheet conveyed from the conveyance apparatus in the stage or a delay amount of a preceding other sheet bundle conveyed from the buffer unit to the post-processing unit. The processor sets a shift amount between plural sheets based on the delay amount obtained by the at least one processor.

A buffer unit receives a sheet and temporarily holds a predetermined number of sheets so as to be overlaid on one another. A stacking unit stacks the predetermined number of sheets conveyed toward a first direction. A moving unit comes into contact with an uppermost sheet among the predetermined number of sheets stacked on the stacking unit and moves the uppermost sheet further toward the first direction. A regulating unit comes into contact with an end portion of the stack of sheets on the stacking unit to regulate the position of the stack of sheets. A control unit controls the predetermined number of sheets.