| 摘要 |
PROBLEM TO BE SOLVED: To prevent drying of a writing tip and a direct flow and a reverse flow of an ink by pressing a back surface of a tip ball by an end of a spring to bring it into close contact with an inner edge of a ball holding part of the tip, and sealing a guide hole by a ball valve loosely engaged within a valve chamber. SOLUTION: Since a guide hole 21c is sealed by bringing a ball valve 25 into close contact with a ball receiving seat 21b of a valve chamber 21d in the state that a tip 6 is turned upward, even if an ink of a back surface of a tip ball 7 is eliminated by upward writing, the ink does not reversely flow. Accordingly, when the tip 6 is turned downward, the ink can immediately flow out so that a blur can be prevented when writing. Since the ball 7 is brought into close contact with the inner edge of a tip holding part by pressing of a spring 9 in the state that the tip 6 is turned downward before writing, a direct flow of the ink can be prevented. Since the ball 7 is finely retracted by a writing pressure, a gap is generated so that the ink can flow out. A maximum diameter of a refill of the ballpoint pen is 3 to 3.5 mm. |
