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 feed device includes a feed roller, a transport roller pair provided further to the downstream side in the transport direction of a sheet than the feed roller, a first motor by which the feed roller is driven, and a second motor by which the transport roller pair is driven, and in which a controller that controls the first motor, and performs a skew removal operation accompanying reverse transport of the sheet by the transport roller pair causes a reverse current and a hold current as suppression currents that suppress the reverse transport amount of the feed roller to the reverse transport amount of the transport roller pair or less to flow to the first motor in at least a part of the skew removal operation.

A sheet processing device in an embodiment includes a conveyance path, a stacker, a post processing section, and vertical alignment members. The conveyance path conveys sheets in a conveying direction and stacks the sheets. The stacker restricts a leading end of the conveyed sheets. The stacker is movable in the conveying direction. The post processing section processes the sheets further on an upstream side in the conveying direction than a position where the sheets are supported by the stacker. The vertical alignment members feed the sheets in the conveying direction toward the stacker. The vertical alignment members are enabled to come into contact with a bundle of the sheets supported by the stacker. The vertical alignment members are movable in the conveying direction integrally with the stacker.

A sheet feeding device has a sheet stacking tray, a sheet stop portion, a sheet feed roller, a separation member, a first urging member, an eccentric cam, a cam follower, a sheet detection mechanism, and a holding mechanism. The holding mechanism holds the separation member at a position away from the sheet feed roller after a half-moon-shaped feed surface has passed across the separation member as the sheet feed roller rotates. Immediately before a sheet starts to be fed, the sheet stacking tray is kept on standby at a standby position radially inward of the outer diameter of the feed surface so that the feedable distance between the feed start position and the sheet stop portion is larger than the detectable distance as the maximum distance between the detectable position at which the sheet can be detected by the sheet detection mechanism and the sheet stop portion.