| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball-point pen tip excellent in writing feel and suppressed in the wears of a ball and a ball seat.SOLUTION: A tip body comprises: a ball holding chamber 3 for holding a ball 9; an ink communication hole 7 formed at a center of a bottom wall 4 of the ball holding chamber; and a plurality of ink circulation grooves 6 extending radially from the ink communication hole. A tip part of the tip body is caulked inward to protrude a portion of the ball held in the ball holding chamber from a tip edge, and the ball is rotatably held. In the ball pen tip, a bottom wall of the ball holding chamber is formed with a curved abutment surface 5 having a curvature different from that of the ball, and the ball abuts against an abutment part 5a or a portion of the abutment surface. Between the ball and the abutment surface, there is formed a first clearance S1 which becomes gradually smaller from a side of the ink communication hole to the abutment part, and there is formed a second clearance S2 which becomes gradually smaller from a leading end side of the ink circulation groove to the abutment part.SELECTED DRAWING: Figure 1 |
