Patent ID: 7857182

Claim:
A stapler comprising: a binding table; a clinch member disposed on the binding table; a staple striking unit disposed above the binding table; a movable stage disposed so as to be slidable with respect to the binding table; and a sheet detecting sensor which is provided so as to be slidable with respect to the movable stage, wherein the sheet detecting sensor detects the end portion of the sheets before the end portion of the sheets is positioned by an engaging portion, and the staple striking unit strikes out a staple based on a detection of the end portion of the sheets by the sheet detecting sensor, wherein the movable stage is formed with the engaging portion, the engaging portion positions an end portion of sheets placed on the movable stage, and the sheets are inserted and bound between the clinch member and the staple striking unit, wherein a recess portion is formed on a rear portion of the movable stage and a pair of pieces interpose the recess portion therebetween, each piece of the pair of pieces has an end portion, the engaging portion is formed on each end portion and the engaging portion has a standing surface extending perpendicular to an insertion direction of the sheets, and the sheet detecting sensor is positioned on an inner side of the recess portion and detects the end portion of the sheets before the end portion of the sheets is positioned by the standing surface, and wherein the sheet detecting sensor has an abutment surface which is parallel to the standing surface of the engaging portion, a plurality of sawtooth portions, each extending in a right-and-left direction, are formed on the abutment surface, and a cut groove opening is formed at a center portion in the right-and-left direction of the abutment surface.