| 摘要 |
PROBLEM TO BE SOLVED: To provide a ballpoint pen of high performance of a low cost by a general purpose tip member by solving a problem in which writing is impossible due to wear of interior of the tip irrespective of remainder of ink in the pen, and a problem such as a skip, direct flow, air entrainment, scratch of a sheet, ejection of a ball due to wear observed in a neutral ballpoint pen when a cap is removed without necessity of a mechanism of special ink, complicate barrel mechanism for pressurizing. SOLUTION: A plurality of channel circumscribing circle diameters for conducting ink to a tip are formed substantially equal to a ball diameter or more therein, and a sealing surface 5 having substantially the same roundness R to that of a ball 1 is formed. And, a seat 6 having substantially the same R as that of the ball is provided rear of the ball. And, their surface roughness is set to 5 μm or less. Further, an article provided with an L-shaped taper, a tip containing a spring for always pressing forward therein or backflow preventing mechanism is combined. |
