| 摘要 |
PROBLEM TO BE SOLVED: To prevent the direct outflow and reverse flow of ink, upward writing and thin writing after a shock is applied to a ballpoint pen, which uses low- viscosity ink, and further prevent the direct outflow of ink even in the case where an accident of detachment of a top end ball happens by any chance. SOLUTION: A pipe-like tip 5 is provided at a forward end of a joint 3, and a top end ball 5a is rotatably held at a tip top end. Another peripheral receiving seat face 21a is provided in the rear of a top end ball receiving seat 5b in an inner hole of the tip, and it is so constituted that the receiving seat face 21a and a narrow-diametral portion of the forward part of a spring 17 penetrating through its receiving seat press the rear face of the top end ball to bring the top end ball into close contact with an inner edge of a ball holding portion of the tip, so that the outflow of ink is checked. Further, under such a condition, it is so constituted that an abutment portion is provided at the forward part of the spring in relationship of being opposed to the receiving seat face and that a gap through which ink can flow is formed between the receiving seat face and the abutment portion. Furthermore, when the top end ball is detached, the abutment portion is brought into close contact with the receiving seat face, and the direct outflow of ink can be prevented. |
