Patent ID: 8490965
Filing Date: 2013-07-23
Classification: B65H

Abstract:
1. A sheet-supplying device comprising: a sheet-accommodating tray that supports a plurality of sheets stacked in a vertical direction, wherein each sheet has a first end portion having a first edge and a second end portion having a second edge; an air jetting unit that blows air to the first edge of a topmost sheet of the plurality of sheets to float the first edge; a sheet-conveying unit formed with a plurality of sucking holes for attracting a floated sheet, only a floated topmost sheet being attracted by the plurality of sucking holes when the first end portion is at a prescribed position in the stacking direction, the sheet-conveying unit conveying the attracted sheet; a raising/lowering unit that raises and lowers the sheet-accommodating tray in the vertical direction; a first position sensor that contacts the first end portion to detect a position of the first end portion of the topmost sheet in the vertical direction; a second position sensor that contacts the second end portion including the second edge by moving in the vertical direction to detect a position of the second edge of the topmost sheet in the vertical direction; and a controlling unit controlling the raising/lowering unit to raise or lower the sheet-accommodating tray based on both the position detected by the first position sensor and the position detected by the second position sensor, wherein the controlling unit controls the raising/lowering unit to raise the sheet-accommodating tray until the first position sensor detects the first end portion before a sheet-conveying operation of the sheet-conveying unit starts, wherein the controlling unit controls the raising/lowering unit to raise the sheet-accommodating tray when determining, based on the position of the second edge detected by the second position sensor, that the plurality of sucking holes cannot attract only the topmost sheet during the sheet-conveying operation.