| 摘要 |
PROBLEM TO BE SOLVED: To obtain a good tip of a ballpoint pen which does not produce scratchiness or blurredness in handwriting. SOLUTION: The diameter of the maximum circumcircle of an ink flow hole is made equal to or larger than that of a ball, while the minimum value of the distance between a radial groove and the external shape of a ball holder is made 80-110% of one half of the difference between the diameter of the maximum circumcircle of the ink flow hole and that of a central hole. |
