Sheet post-processing apparatus with pair of side end cursors pivotable toward and away from tray and movable in sheet width direction, and image formation system with sheet post-processing apparatus

A sheet post-processing apparatus comprising:

• a post-processing device that subjects a sheet to post-processing;
• an ejection roller that ejects the sheet;
• a tray on which a plurality of sheets ejected by the ejection roller are to be loaded;
• a pair of side end cursors provided above the tray and the ejection roller pivotably toward and away from the tray and opposed to each other in a width direction of the sheet orthogonal to a direction of ejection of the sheet movably in the width direction;
• a first drive device that pivots each of the side end cursors toward and away from the tray;
• a second drive device that moves each of the side end cursors in the width direction;
• and
• a control device that includes a processor and controls, through the processor executing a control program, the first drive device and the second drive device,
• wherein the control device successively performs:
• a control in a first mode to allow the first drive device to pivot each of the side end cursors away from the tray to thus move the side end cursors to respective predetermined first positions where edges of the side end cursors facing the tray are located above and away from the tray and come into contact with the sheet ejected by the ejection roller and allow the second drive device to move each of the side end cursors to respective holding positions located inwardly of the sheet in the width direction;
• and
• a control in a second mode to allow the second drive device to move each of the side end cursors in the width direction to respective predetermined lateral positions located outwardly of the sheet in the width direction, allow the first drive device to pivot each of the side end cursors toward the tray to thus move the side end cursors to respective predetermined second positions where the edges of the side end cursors facing the tray come close to or into contact with the tray, and then allow the second drive device to move each of the side end cursors from the lateral positions to respective predetermined abutment positions where the side end cursors abut against ends of the sheet in the width direction,
• wherein the side end cursors are mounted at respective upstream ends thereof in the direction of ejection to respective pins extending in the width direction and supported by the pins, and
• the first drive device rotates the pins and thus pivots the side end cursors toward and away from the tray,
• the sheet post-processing apparatus further comprises covers provided around the respective pins and extending downward beyond the upstream ends of the side end cursors supported by the pins to a location of contact with a sheet ejected by the ejection roller during the control in the first mode.