SHEET FEEDING DEVICE AND IMAGE FORMING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a sheet feeding device and an image forming device which enable continuous and smooth paper-feeding by loading a large number of pieces of envelopes and the like in the same manner as general cut sheets on the sheet feeding device of large capacity.SOLUTION: A paper-feeding deck includes: a lifter motor for moving a lifter tray 107 upward/downward; a paper-feeding roller 101 for coming into contact with an uppermost sheet out of sheets S on the lifter tray 107, and for feeding the sheets S; and a sheet presence/absence detection sensor 201 for detecting presence/absence of the sheet S. The paper-feeding deck includes: a position detection sensor 205 for detection a height position of the lifter tray 107; and control means for controlling so that a positional relationship between the lifter tray 107 and the uppermost sheet is maintained constant by an operation of the lifter motor. The control means validates a detection result by the position detection sensor 205 after the height position of the lifter tray 107 based on the detection of the position detection sensor 205 surpasses a predetermined height (point W).