| 摘要 |
PROBLEM TO BE SOLVED: To prevent an interior of a barrel of a ballpoint pen, the hand or a clothing from being stained by preventing a reverse flow of an ink generated by upward writing or an impact and to eliminate a problem due to occurrence of bubbles by preventing bubbles from being formed in the ink due to a centrifugal step, a temperature change or an aging to avoid bubbles after an elapse of long time. SOLUTION: The ballpoint pen comprises a tip fixed to a distal end of a joint, an ink housing tube fixed to a rear end of the joint, a bush fastened to a rear end hole of the tip, a valve chamber provided at the rear side of the bush at an axial center of the joint and a tapered or spherical surface-like ball bearing seat provided at the rear part of the chamber in such a manner that a ball valve is movably engaged within the chamber. In the ink tube, a low viscosity ink is filled to follow to the ink at the rear end of the ink in a movable grease-like state. The ballpoint pen further comprises a groove of a suitable depth formed on pass through the longitudinal end of a required position of the outer periphery of the bush. |
