Patent ID: 7510106

Claim:
A driver structure configured to drive a U-character shaped staple including a pair of leg portions configured to pass through a bundle of papers and a crown for connecting the pair of leg portions, the driver structure comprising: a blade edge disposed to be in contact with the staple; a first pair of projections, each projection of said first pair being provided at an opposite end portion of the blade edge, and being disposed to be in contact with a corner formed between the crown and one of the leg portions for pressing the leg portion perpendicularly while retaining opposite ends of the crown inwardly when the leg portion passes through the bundle of papers; a second pair of projections, each projection of said second pair being provided on the blade edge in vicinity of one of the projections of said first pair, and being configured to be in contact with the crown in vicinity of one of the leg portions when the leg portion passes through the bundle of papers; and a middle projection provided on the blade edge between the projections of said second pair, to hold the crown of the staple when the pair of leg portions pass through the bundle of papers, the middle projection comprising a crown pressing portion to press the crown; and cutouts formed between each projection of said second pair and the crown pressing portion to substantially form portions of each projection of said second pair contacting with the crown of the staple perpendicularly to be in engagement with the crown, wherein each projection of said second pair has a corner portion disposed adjacent to one of the corners of the staple, which engages with the crown and is configured to prevent the corner of the staple from slipping toward a central side of the crown, wherein each projection of said first pair has a guiding surface positioned at least partially outside of an outside edge of one of the leg portions, so as to guide said outside edge of the leg portion and restrict the broadening of a leading end of the leg portion when the leg portion of the staple passes through the bundle of papers, and wherein the crown is held by the first pair of projections, the second pair of projections and the crown pressing portion when stapling the bundle of papers.