| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a pipe type ball-point pen tip which can secure a sufficient ink outflow property though adopting an extremely small ball and in which the extremely small ball can be held stably over a long period of time without being dropped out. <P>SOLUTION: The pipe type ball-point pen tip is constituted in such a manner that: the ball 3 is held rotatably by a plurality of inward projecting parts 5 each of which is formed by press-deforming the vicinity of the tip of a metallic pipe 2 inward in the radial direction and used for a ball receiving seat, and a tip edge 4 which is formed by press-deforming the tip of the pipe 2 inward in the radial direction and circularly; and a conical concave plane 6 is formed on the front surface of the inward projecting part 5. The diameter of the ball 3 is ≤0.4 mm and the tilt angle α of the conical concave plane 6 is 75-90°. The pipe type ball-point pen tip satisfies a relationship of [(A-C)/2]<[(B-C)/2], where A is the minimum inside diameter of the tip edge 4; C is the diameter of the ball 3; B is the inside diameter of the pipe 2 between the tip edge 4 and the inward projecting part 5. <P>COPYRIGHT: (C)2012,JPO&INPIT |
