Patent ID: 8177222

Claim:
A sheet feeding apparatus comprising: a tray which stacks a plurality of sheets and is raiseable or lowerable; an air blowing portion which blows air toward the ends of the sheets stacked on the tray to loosen the sheets; a conveying portion which conveys an uppermost sheet positioned within a predetermined range among the sheets loosened by the air from the air blowing portion; a sheet detecting portion which detects whether the uppermost sheet loosened by the air from the air blowing portion is positioned within the predetermined range; a sheet surface detecting portion which detects an uppermost position of the sheets stacked on the tray; a tray detecting portion which detects a reference position of the tray below the sheet surface detecting portion in a sheet stacking direction; a tray movement detecting portion which detects the amount of movement of the tray; a controlling portion which moves the tray from the reference position to a position at which the uppermost position of the sheets stacked on the tray is detected by the sheet surface detecting position, and moves the tray from which the uppermost sheet loosened by the air from the air blowing portion is positioned within the predetermined range based on a detection by the sheet detecting portion; a remaining amount calculation portion which calculates the amount of the sheets stacked on the tray from (m+q), where (m) represents the amount of movement of the tray from the reference position of the tray detected by the tray detecting portion to the uppermost position of the sheets on the tray detected by the sheet surface detecting portion, and (q) represents the amount of movement of the tray from which the uppermost sheet loosened by the air from the air blowing portion is moved from outside the predetermined range to within the predetermined range detected by the tray movement detection portion; and a remaining amount displaying portion which displays the amount of the sheets stacked on the tray calculated by the remaining amount calculation portion.