| 摘要 |
PROBLEM TO BE SOLVED: To prevent the back flow and the direct flow of an ink, and a writing blurring due to dryness or the like from arising by a method wherein a ball-shaped plug body which comes into contact with the tip end of a spring in a tip, and is confronted with a front step part while having an ink circulating gap between them, pushes the back surface of a tip end ball through a contact part. SOLUTION: A tip 1 loosely holds a tip end ball 2 by a ball holding part 1c and a receiving seat surface 1d, and a spring 3 is loosely inserted inside. A ball-shaped plug body 6 is provided in a manner to be in contact with the tip end of the spring 3, and a short dimension thinner diametrical contact part 7 is provided in a manner to be in contact with the tip end of the plug body 6. The tip end of the contact part 7 comes into contact with the back surface of the tip end ball 2 like pressing, and the tip end ball 2 is joined to the internal edge of the holding part 1c. With a tapered or spherical step part 1f which is formed at a rear part of a central hole 1e, the tip end of the plug body 6 is confronted while having a proper gap where an ink can flow in. Other than the time of writing, the tip end ball 2 joins to the internal edge of the ball holding part 1c, and a direct flow and a back flow of the ink, and a writing blurring due to dryness or the like can be prevented from arising. |
