| 摘要 |
PURPOSE: To prevent leakage of ink, failure in writing function, blurred writing and the like from occurring by a method wherein a float having a through-hole, which is communicatingly opened to the rear surface on the atmospheric side, is provided in highly viscous fluid layer, which is formed so as to move together with the interface of ink as the ink within an ink tank is spent. CONSTITUTION: A writing utensil A has a shaft tube 1, the interior of which serves as an ink tank and at the tip of the small diameter part of which a pen point is mounted, in which highly viscous fluid layer 4 as an ink back-flow preventing body and a float 5 immersed in the highly viscous fluid layer are arranged in the interfacial portion of ink. The float 5 has its front face 5a made parallel to the interface between the ink and the highly viscous fluid layer 4 and, in addition, has a through hole 6, which is opened to both fore face 5 and a rear face 5b and diametrically expanded towards the rear. Further, the leakage of the ink is prevented from occurring by dispersing the force in the direction developing at the insertion of the float 5 through the movement of the highly viscous fluid in the through-hole 6. |
