Patent ID: 6994341
Filing Date: 2006-02-07
Classification: B65H

Abstract:
1. A sheet feeding device comprising: sheet containing means detachably attached to an apparatus main body for containing sheets; sheet pick-up means adapted to vertically move for feeding the sheet contained in said sheet containing means, a sheet support member provided in the sheet containing means and adapted to vertically move while supporting the sheets; lifter means for raising said sheet support member so as to bring an uppermost surface of the sheets supported by said sheet support member to a predetermined height; a cam member mounted rotatably and adapted to lower the sheet pick-up means so as to bring it into contact with the sheets when the uppermost surface of the sheets is raised to the predetermined height, and adapted to raise the sheet pick-up means to an upper initial position above the uppermost surface of the sheets on standby; detection means for detecting a height of the uppermost surface of the sheets according to a position at which the sheet pick-up means contact with the sheets; and control means for controlling the raising operations of said lifter means on the basis of the result of the detection of the height of the uppermost surface of the sheets so as to maintain the uppermost surface of the sheets supported by the sheet support member at a predetermined height, wherein, when the sheet containing means is attached in the apparatus main body, and said cam member is pressurized and rotated by said sheet containing means, so the raising operation of said cam member is canceled by the rotation of the cam member, and the sheet pick-up means is lowered from the upper initial position so as to enable said detection means to perform detection.