Post-processing apparatus for performing given process subsequently to image forming process by image forming apparatus is disclosed. Post-processing apparatus includes: first ejector which ejects sheet; first tray which temporarily holds sheet; second tray situated downstream of first tray in ejection direction of sheet; a tray driver which moves second tray downwardly from first height position; blower which forms airstream between second tray and lower surface of sheet; and controller which controls blower and tray driver. Controller includes: blower controller which causes blower to blow air over time period in synchronization with first time period from start to end of sheet ejection by first ejector; and tray controller which causes tray driver to move second tray downwardly from first height position after first time period.

Post-processing apparatus for performing given process subsequently to image forming process by image forming apparatus is disclosed. Post-processing apparatus includes: first ejector which ejects sheet; first tray which temporarily holds sheet; second tray situated downstream of first tray in ejection direction of sheet; a tray driver which moves second tray downwardly from first height position; blower which forms airstream between second tray and lower surface of sheet; and controller which controls blower and tray driver. Controller includes: blower controller which causes blower to blow air over time period in synchronization with first time period from start to end of sheet ejection by first ejector; and tray controller which causes tray driver to move second tray downwardly from first height position after first time period.

A sheet stacking device includes a sheet outlet, a lower discharge roller, and a paddle member. The paddle member is disposed coaxially to a rotation shaft of the lower discharge roller, and is driven to rotate independently of the lower discharge roller in the same direction as the lower discharge roller, so as to contact downward an upstream part in a discharging direction of a sheet discharged through the sheet outlet. The paddle member includes a base part in which the rotation shaft is inserted, an arm part protruding in a direction separating from an axis center of the base part, and a paddle elastic part protruding from the arm part. A rotation speed of the paddle member is the same as a rotation speed of a discharge roller pair when the sheet passes through a nip of the discharge roller pair.

A sheet stacking device includes a sheet outlet, a lower discharge roller, and a paddle member. The paddle member is disposed coaxially to a rotation shaft of the lower discharge roller, and is driven to rotate independently of the lower discharge roller in the same direction as the lower discharge roller, so as to contact downward an upstream part in a discharging direction of a sheet discharged through the sheet outlet. The paddle member includes a base part in which the rotation shaft is inserted, an arm part protruding in a direction separating from an axis center of the base part, and a paddle elastic part protruding from the arm part. A rotation speed of the paddle member is the same as a rotation speed of a discharge roller pair when the sheet passes through a nip of the discharge roller pair.

A post-processing device includes a carrying roller, a conveying member, a transporting member and a processing part. The carrying roller is configured to be rotated to carry a sheet one by one to a processing tray along a conveyance direction. The conveying member is configured to convey the sheet carried by the carrying roller to a receiving position on the processing tray. The conveying member has a rotation shaft and a plurality of contact pieces protruding from the rotation shaft so as to come into contact with the sheet carried on the processing tray. The contact piece is made of elastic material. The conveying member is rotated at a rotation speed higher than a rotation speed of the carrying roller when the sheet carried by the carrying roller is conveyed to the receiving position on the processing tray.

A post-processing device includes a carrying roller, a conveying member, a transporting member and a processing part. The carrying roller is configured to be rotated to carry a sheet one by one to a processing tray along a conveyance direction. The conveying member is configured to convey the sheet carried by the carrying roller to a receiving position on the processing tray. The conveying member has a rotation shaft and a plurality of contact pieces protruding from the rotation shaft so as to come into contact with the sheet carried on the processing tray. The contact piece is made of elastic material. The conveying member is rotated at a rotation speed higher than a rotation speed of the carrying roller when the sheet carried by the carrying roller is conveyed to the receiving position on the processing tray.

The relay conveyance device includes a relay conveyance path, a plurality of conveyance members, at least one detection member and a control device. The control device executes a correction processing such that, in a state where a first sheet and a second sheet positioned at the upstream side from the first sheet are conveyed along the relay conveyance path, a sheet interval from a detection end of the first sheet by the detection member to a detection start of the second sheet by the detection member is compared with a predetermined target value, when the sheet interval is smaller than the target value, the conveyance speed of the conveyance member is decreased so as to widen the sheet interval, and when the sheet interval is larger than the target value, the conveyance speed of the conveyance member is increased so as to shorten the sheet interval.

The relay conveyance device includes a relay conveyance path, a plurality of conveyance members, at least one detection member and a control device. The control device executes a correction processing such that, in a state where a first sheet and a second sheet positioned at the upstream side from the first sheet are conveyed along the relay conveyance path, a sheet interval from a detection end of the first sheet by the detection member to a detection start of the second sheet by the detection member is compared with a predetermined target value, when the sheet interval is smaller than the target value, the conveyance speed of the conveyance member is decreased so as to widen the sheet interval, and when the sheet interval is larger than the target value, the conveyance speed of the conveyance member is increased so as to shorten the sheet interval.

In a sheet postprocessing apparatus, an accommodation paddle increases a rate of increase in transport force generated for sheets by the accommodation paddle, in conjunction with a rate of increase in transport resistance generated for the sheets by a sheet pressing member with an increase in number of the sheets stacked on a sheet stacker.

In a sheet postprocessing apparatus, an accommodation paddle increases a rate of increase in transport force generated for sheets by the accommodation paddle, in conjunction with a rate of increase in transport resistance generated for the sheets by a sheet pressing member with an increase in number of the sheets stacked on a sheet stacker.