Sheet aligning apparatus

A sheet aligning apparatus comprising:

• a discharging section to discharge sheets;
• a tray on which the sheets discharged from the discharging section are stacked;
• a sorting section to sort the sheets to be stacked on the tray in a direction perpendicular to the discharging direction of the sheets;
• a pair of sheet aligning members to align both edges of the sheets sorted and stacked on the tray, wherein the both edges of sheets are located in a direction perpendicular to the conveying direction of the sheets;
• a control section to control the pair of sheet aligning members to stop at least three positions in a vertical direction in such a way that:
• when a sheet aligning operation is not conducted, the pair of sheet aligning members stops at the first position of an upper level so as not to come in contact with sheets discharged from the discharging section,
• when the sorting section shifts for sorting sheets, the pair of sheet aligning members stops at the second position of a middle level lower than the first position so as not to come in contact with sheets stacked on the tray, and
• when a sheet aligning operation is conducted, the pair of sheet aligning members stops at the third position of a lower level so as to come in contact with the top surface of the tray or the upper surface of sheets stacked on the tray.