| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a fear of leaking ink from an air vent of a tail cap fitted on the tail end of a shaft cylinder to the outside even in the case of losing the sealing effect of a backflow preventing agent when a writing instrument is placed facing upward. SOLUTION: In a direct liquid type writing instrument in which ink is directly filled in a shaft cylinder 1 with a pen body tip 2 disposed at the front end and a tail cap 5 fitted on the tail end and the tail end side of the ink is sealed by a paste-like backflow preventing body 6, a check valve constituted of a valve 9 as a ball and a seat component 8 is disposed on the tail cap 5, and an ink reservoir section 53 is formed on the tail end side of the check valve. |
