A buffer means includes a buffer unit that makes paper sheets temporarily stand by and a paper stacking unit that intermittently conveys paper sheets and sucks the trailing edges of the paper sheets to stack the paper sheets stepwise and make them temporarily stand by.

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.

There is provided a sheet processing apparatus with improved visibility of a sheet bundle discharged without post-processing thereto. The CPU circuit receives the conveyed sheet, drives and controls the sheet-returning paddle, the rack part, the rear end regulation part, the alignment plate and the like and forms sheet bundle comprising of a plural number of sheets as received. Further, the CPU circuit drives and controls the alignment plate when discharging the sheet bundle S from the processing tray, the sheet bundle S exceeding the number of sheets which can be post-processed by the stapler. Therefore, the sheet bundle S which includes sheets equal to the allowable number of sheets for post-processing of the sheet processing unit is discharged to the second discharge position which is different from the first discharge position.

A sheet binding device includes a sheet shifting unit, a tape cutter, and a tape attachment unit. The sheet shifting unit has a guide and is configured to stack multiple sheets on the guide with edge portions that are shifted from each other to form a sheet bundle. The tape cutter cuts tape with a target length that is varied in accordance with a thickness of the sheet bundle. The tape attachment unit is configured to attach the cut tape having the target length to an edge portion of the sheet bundle.

A sheet binding device according to an embodiment includes a tape attachment unit and a sheet support unit. The tape attachment unit includes a tap holding unit configured to hold tape that is to be applied to an edge portion of a sheet bundle at a tape attachment region of the edge portion. The sheet support unit holds the sheet bundle in a state where multiple sheets forming the sheet bundle are shifted relative to each other in the edge portion when the tape is applied by the tape attachment unit. The sheet support unit also presses, in a sheet bundle thickness direction, a pressing region of the edge portion different from the tape attachment region so that there is substantially no slack along the edge portion of the sheet bundle between the pressing region and the tape attachment region.

A sheet binding method according to an embodiment includes holding a sheet bundle in a state where multiple sheets forming the sheet bundle are shifted relative to each other at an edge portion of the sheet bundle. A pressing region of the edge portion is pressed, in a sheet bundle thickness direction, so that there is substantially no slack along the edge portion. While the sheet bundle is pressed, tape is applied to an edge portion of a sheet bundle at a tape attachment region of the edge portion different from the pressing region.

A sheet feeding apparatus includes a first sheet storage portion and a second sheet storage portion disposed side by side with the first sheet storage portion. The sheet feeding device includes a sheet bundle moving member configured to transfer sheets in the second sheet storage portion to the first sheet storage portion and a pickup roller configured to feed the sheet by abutting against the sheet stored in the first sheet storage portion. When transferring the sheet bundle in the second sheet storage portion to the first sheet storage portion, the pickup roller is rotated in the same direction as that during feeding.

A post-processing device includes a stacking portion on which a medium having an image recorded thereon is stacked; an aligning portion that is disposed on the stacking portion and that aligns a position of an edge of the medium; a drawing member that draws the medium stacked on the stacking portion toward the aligning portion; and a guiding member that is disposed above the drawing member and that guides the medium that is transported toward the stacking portion, the guiding member including a vicinity portion that is in a vicinity of the drawing member and that is recessed so as to receive the drawing member.

A post-processing device includes a stacking portion on which a medium having an image recorded thereon is stacked; an aligning portion that is disposed on the stacking portion and that aligns a position of an edge of the medium; a drawing member that draws the medium stacked on the stacking portion toward the aligning portion; and a guiding member that is disposed above the drawing member and that guides the medium that is transported toward the stacking portion, the guiding member including a vicinity portion that is in a vicinity of the drawing member and that is recessed so as to receive the drawing member.

A floating clamp mechanism prevents sheets from migrating back from a lead edge registration wall during the compiling of sheets in a stacker. The floating clamp mechanism includes a spring loaded ball mounted in converging upper and lower tracks that act as a one-way clutch. This allows the incoming sheets to be scuffed with low force to the lead edge registration wall while simultaneously holding the registered sheets to the registration wall.