| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball receiving seat with sufficient strength an easy inward deformation, sufficient outflow of ink, smooth rotation of ball, even using a big ball. SOLUTION: The ball point pen tip 1 is the type of inwardly deforming a neighborhood of the top of metallic pipe body 2, forming the inside protrusion 3 for the ball receiving seat, and satisfies a relation A/T>5.8, where A is an outside diameter of the ball 5, T is a thickness of the pipe body 2. Also, it satisfies a relation A/D>2.0, where D is a depth of concave 32 formed in an outside of the inner protrusion 3. |
