Patent ID: 8794618

Claim:
A sheet feeding device comprising: a sheet containing section; a lift plate for lifting up and down sheets stacked in the sheet containing section between a sheet feeding position and a sheet loading position; a sheet feeding section for separating and feeding the sheets in the sheet feeding position one after another; and a lifting mechanism for lifting up and down the lift plate, the lifting mechanism including: a biasing member disposed at a side of lift plate for biasing the lift plate toward the sheet feeding section; a cam, having an outer peripheral surface with a cam curve, fixed to a rotation shaft independent from the sheet feeding section so as to be coupled with a driving force source and rotated thereby; and an operating lever disposed at an opposite side of the lift plate that is opposite said side at which the biasing member is disposed, and provided independently of and between the cam and the lift plate so as to always remain in contact with the outer peripheral surface of the cam and the lift plate, and to simultaneously press the lift plate against a biasing force of the biasing member, thereby to change a posture of the lift plate between the sheet feeding position and the sheet loading position, wherein the lifting mechanism keeps the lift plate in a lowest posture when not feeding a sheet, rotates the cam to raise the lift plate to the sheet feed position so as to keep an uppermost one of the sheets in the sheet feeding position before feeding out the uppermost one sheet and then starts feeding the uppermost one sheet, rotates the cam to move the lift plate back into the lowest posture when a sheet in the sheet containing section is detected as the last sheet therein, and controls the posture of the lift plate by rotating the cam, which always remains in contact with the lift plate, via the operating lever such that the lift plate remains in the sheet feeding position and the sheet feeding section is in contact with the uppermost one sheet so long as a sheet is present in the sheet containing section, irrespective of a number of sheets.