| 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. SOLUTION: A partitioning portion 21a is provided in an inner hole of a fitting cylinder 12, and lateral holes 20a, 20b communicating to a fore end hole and a rear end hole, respectively, are bored at an outer peripheral portion of the fitting cylinder. Further, the outer peripheral portion is provided with a groove communicating between the lateral holes, has also a flange 27, and is provided with a piece 13 at a top end of a shaft portion. The piece is so formed that a spring 22 is urged to allow the tip of a narrow-diametral portion 17 of the piece to abut with a rear face of a top end ball 5a so that the top end ball is brought into close contact with an inner edge of a holding portion at a forward end of a tip 5. Furthermore, a seal face 16 is provided at the front face of a flange 15 of the piece and, under the condition that the top end ball is in close contact with the inner edge of the holding portion at the forward end of the tip, a gap through which ink can flow in is formed between a rear end face of the tip and the seal face, or by providing a seal face 25, which can be in close contact with a seal step 26 of the tip, in the rear of the narrow-diametral portion of the piece, a gap through which ink can flow in is formed between the seal step of the tip and the seal face of the piece. |
