| 摘要 |
PROBLEM TO BE SOLVED: To enable prevention of a direct flow or a reverse flow of an ink in a ballpoint pen immediately filling the ink having low viscosity or so-called shear-rate thinning in a thick barrel. SOLUTION: The ballpoint pen comprises a tip thereof at a distal end of a distal barrel and a barrel directly filled with the ink at a rear side of the distal barrel. The pen further comprises a spring internally inserted into the inner hole of the tip and provided so as not to be drawn from the rear end of the tip to urge the rear end of the distal end ball rotatably held by the distal end of the tip at the head of the spring, so that the ball is closely contacted with the inner edge of the ball holding part of the tip. In the barrel, the ink having low viscosity or the ink having steadily high viscosity to lower the viscosity by a rotation of the ball at a writing time to have shear-rate thinning capable of flowing out. Further, the pen comprises a grease-like follower capable of following in contact with the ink as the ink is consumed at a rear end of the ink, and a follower bar made of a resin having substantially same specific gravity as that of the follower dipped therein. |
