| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball point pen which prevents the inversion between a backflow preventing material and ink when the ink of large specific gravity incorporated with a coloring material of large hiding power is allowed to stand upward to be able to write clearly on dark-colored paper and others. SOLUTION: In a ball point pen, an ink housing part in which the nib of the pen is fitted to one end is filled with ink and an ink backflow preventing material. A disk of a material of specific gravity the value of which is between those of the ink and the ink backflow preventing material is arranged between the ink and the ink backflow preventing material. |
