Patent ID: 8272634
Filing Date: 2012-09-25
Classification: B65H

Abstract:
1. A sheet feeding device, comprising: a tray which may be moved upward and downward in a state in which a plurality of sheets are stacked; an air blowing unit which blows air onto a sheet stacked in the tray for floating and loosening; an absorption conveying unit which absorbs and conveys a uppermost sheet of the sheets stacked on the tray floated by blowing air blown by the air blowing unit at a feed position; a sheet detection portion which detects a position of the uppermost sheet floated by blowing of the air blowing unit; a tray moving unit which moves the tray upward and downward; a tray moving amount detection portion which detects a moving amount of the tray caused by the tray moving unit; a control portion which controls the tray moving unit so as to move the tray in such a way that the uppermost sheet floated by blowing air is located at a feed position, where the uppermost sheet may be absorbed and conveyed by the absorption conveying unit, based on detection of the sheet detection portion; and a ROM which stores a basis weight-moving amount table of the moving amount of the tray according to a basis weight of the sheet, wherein when the uppermost sheet floated by blowing air is moved to the feed position from a position outside of the feeding position, the control portion discriminates the sheet basis weight of the sheets on the tray from the basis weight-moving amount table of the ROM based on the moving amount of the tray detected by the tray moving amount detection portion.