Sheet discharging apparatus, sheet processing apparatus, and image forming system

A sheet discharging apparatus comprising:

• a stacking portion on which a sheet is stacked;
• a first conveyance portion that is disposed on a first conveyance path extending toward the stacking portion and that is configured to convey a sheet toward the stacking portion;
• a detection portion configured to output a detection signal in response to a sheet that is passing through the first conveyance path;
• a second conveyance portion disposed downstream of the first conveyance portion in the first conveyance path and configured to reverse a conveyance direction of a sheet that the second conveyance portion has received from the first conveyance portion and convey the sheet to a second conveyance path, the second conveyance path being a path branched from a portion of the first conveyance path between the first conveyance portion and the second conveyance portion;
• a third conveyance portion disposed on the second conveyance path and configured to reverse a conveyance direction of a sheet and convey the sheet;
• and
• a control portion configured to control the first conveyance portion, the second conveyance portion, and the third conveyance portion, the control portion being configured to execute a discharge operation by causing the sheet discharging apparatus to:
• (1) reverse a conveyance direction of a first sheet conveyed from the first conveyance portion to the second conveyance portion and deliver the first sheet to the third conveyance portion by using the second conveyance portion;
• (2) convey the first sheet toward the second conveyance portion by using the third conveyance portion, depending on the detection signal outputted by the detection portion in response to a second sheet that is conveyed following the first sheet;
• and
• (3) discharge the first sheet and the second sheet to the stacking portion by using the second conveyance portion in a state where the first sheet and the second sheet are superimposed on each other such that an edge portion of the first sheet in the conveyance direction thereof and an edge portion of the second sheet in a conveyance direction thereof are aligned with each other,
• wherein the control portion is configured to change a stop position of a leading edge of the first sheet in accordance with a length of the first sheet in the conveyance direction of the first sheet, the leading edge of the first sheet being an edge in a direction from the second conveyance portion toward the third conveyance portion, the stop position being a position at which conveyance of the first sheet by the third conveyance portion is stopped after the first sheet is delivered to the third conveyance portion.