A sheet binding processing apparatus includes a conveying portion, a conveying path for sheets, a stacking portion on which sheets from the conveying path are stacked, a first regulating portion for regulating a sheet bundle on the stacking portion in a crossing direction, a second regulating portion for regulating a sheet bundle in the conveying direction, a manual setting portion for setting sheets from an outside of the apparatus, and a binding device which binds a sheet bundle by a staple and moves in the crossing direction. An angular posture of the binding device located at a third position is different from an angular posture located at a first position. An angular posture of the binding device located at the third position is different from an angular posture located at a second position. The second position is located at a second side of the first position.

A medium transport device includes a feeding unit that transports a medium, a stack portion that receives the medium transported by the feeding unit between a support surface for supporting the medium in an inclined posture in which a downstream side in a transport direction is directed downward and an opposing surface opposing the support surface and stacks the medium, an alignment portion that aligns a downstream end of the medium stacked in the stack portion, a paddle that is provided between the feeding unit and the alignment portion in the transport direction and moves the medium toward the alignment portion by rotating while being in contact with the medium, and a control unit that controls an operation of the paddle, in which the control unit controls the operation of the paddle according to a condition.

A post-processing apparatus includes a post-processing unit configured to receive sheets from an image forming apparatus, perform processing on the received sheets, and then discharge the processed sheets through a discharge port. A sensor is configured to detect a presence of an object at the discharge port. The sensor includes a first light emitter on a first side of the discharge port that is positioned to emit a light across a width of the discharge port, a reflector on a second side of the discharge port opposite the first side in a first direction, and a first light receiver positioned to receive light of the first light emitter from the reflector. A controller is configured to terminate the processing on the received sheets by the post-processing unit when the sensor detects the presence of the object at the discharge port.

Provided are a post-processing apparatus, an image forming apparatus, and a post-processing method capable of avoiding the occurrence of a malfunction due to a failure to discharge a sheet bundle after a binding process. A plurality of sheets is loaded on a stack tray. A staple unit binds the plurality of sheets. A discharge roller discharges the sheet bundle bound by the staple unit from the stack tray. Each time a sheet is conveyed to the stack tray, an aligning unit moves between a first position in contact with the sheet loaded on the stack tray and a second position separating from the sheet. A detection processing unit detects a failure of discharging the sheet bundle by the discharging roller. A stop processing unit can stop the operation of the aligning unit when the discharge failure is detected by the detection processing unit.

A sheet discharging device includes: a medium supporting portion configured to support a transported medium, the medium supporting portion being configured to swing; a stacking portion which is provided vertically below the medium supporting portion and on which the medium dropped from the medium supporting portion is stacked, the stacking portion being configured to move up and down; and a detecting portion that detects swinging of the medium supporting portion, in which the detecting portion detects the swinging of the medium supporting portion when the medium on the rising stacking portion comes into contact with a lower surface of the medium supporting portion.

A sheet post-processor includes a processing tray, a sheet discharge port, a discharge roller pair, a pair of cursor members, a pair of support members, and an interlocking mechanism. The interlocking mechanism includes a pair of coupling members arranged in the processing tray so as to be reciprocatable in a sheet width direction. The pair of coupling members are coupled to or decoupled from the pair of cursor members in accordance with movement of the pair of cursor members. While being coupled to the pair of cursor members, the pair of coupling members contact the pair of support members so as to displace the pair of support members to a protruding position, and while being decoupled from the pair of cursor members, the pair of coupling members separate from the pair of support members so as to displace the pair of support members to a retracted position.

A sheet discharge apparatus includes a first tray for stacking sheets, and a sheet bundle forming unit that forms a sheet bundle on the first tray. The sheet bundle forming unit forms a first sheet bundle on the first tray, and forms a second sheet bundle on the first sheet bundle to be offset from the first sheet bundle. When forming each of the first sheet bundle and the second sheet bundle on the first tray, the sheet bundle forming unit divides sheets constituting each of the sheet bundles into a plurality of sets and discharges the sheets in a plurality of times for each sheet bundle. A number of sheets included in a first sheet set of the first sheet bundle is set smaller than a number of sheets included in a first sheet set of the second sheet bundle.

A sheet processing apparatus includes a conveyance member to convey a sheet, a pair of alignment members to move relatively in a width direction orthogonal to a conveyance direction of the sheet by the conveyance member, so as to align a position of the sheet in the width direction, and a lower portion to support a lower surface of the sheet between the pair of alignment members in the width direction. In addition, a pair of upper portions are arranged on one side and the other side of the lower portion in the width direction and each hold an upper surface of the sheet, wherein the pair of upper portions is positioned lower than the lower portion in a plane vertical to the conveyance direction.

In order to properly suppress a discharge defect corresponding to an image ratio of a sheet, in the case where a coefficient of friction is different according to the image ratio of an image on the sheet, an air blowing section is arranged to blow air toward a downstream side in a transport direction from between a downstream-side end portion of a first stacking section and an upstream-side end portion of a second stacking section. When an image ratio of an image on a sheet by an image forming apparatus is a first value, the air blowing section sets an air quantity blown to the sheet at a first air quantity F1, while when the image ratio is a second value higher than the first value, setting the air quantity blown to the sheet at a second air quantity F2 larger than the first air quantity F1.

A sheet post-processor includes a processing tray, a sheet discharge port, a discharge roller pair, a pair of cursor members, a pair of support members, and an interlocking mechanism. The interlocking mechanism includes a pair of coupling members arranged in the processing tray so as to be reciprocatable in a sheet width direction. The pair of coupling members are coupled to or decoupled from the pair of cursor members in accordance with movement of the pair of cursor members. While being coupled to the pair of cursor members, the pair of coupling members contact the pair of support members so as to displace the pair of support members to a protruding position, and while being decoupled from the pair of cursor members, the pair of coupling members separate from the pair of support members so as to displace the pair of support members to a retracted position.