Abstract: An automatic sheet feeding system of a printing apparatus comprising a platen, a printing head, a sheet ejecting stacker and a sheet feeding stacker. The platen remains stationary when the leading edge of a sheet fed by the sheet feeding roller has abutted against the platen, whereby the tilting position of the sheet can be corrected. The system comprises further sheet leading edge detecting means disposed at the inlet of the sheet ejecting passage near the platen. When the detecting means detects the leading edge of a sheet, the platen can be rotated in the reverse direction through a predetermined angle for setting the printing initiating position on a sheet at a predetermined distance from the leading edge of the sheet.