SHEET STORAGE DEVICE, POST-PROCESSING DEVICE USING THE SAME, AND IMAGE FORMING DEVICE

PROBLEM TO BE SOLVED: To provide a sheet storage device capable of simplifying a sensor mechanism for detecting the sheet surface level when stacking and storing sheets, preventing the sheets from being folded, and at the same time, reducing its power consumption. SOLUTION: The sheet storage device comprises a tray means for stacking and storing sheets from a paper discharge port, a paper discharge means arranged at the paper discharge port to discharge the sheets to the tray means, and a sheet surface detection means for detecting the sheet surface level of the highest sheet on the tray means. The sheet surface detection means comprises a sensor lever, a detection sensor for detecting the position of the sensor lever, and a lever driving means for shifting the sensor lever between the sheet surface detection position for engagement with the highest sheet on the tray means and the retreated position for retreated from the highest sheet. A paddle member having an elastic piece for pressing the highest sheet on the tray means, and a paddle driving means for turning the paddle member are arranged at the paper discharge port. COPYRIGHT: (C)2009,JPO&INPIT