| 摘要 |
PROBLEM TO BE SOLVED: To prevent back flow of ink by upward writing and a shock in the ball-point pen with a fine point for using ink of low viscosity or ink having shear-thinning properties which basically has low viscosity but statically has high viscosity and flows out because viscosity is lowered by rotation of a ball at time of writing. SOLUTION: The ball-point pen is constituted by providing the tip 5 of the ball-point pen formed of a capillary, in which the diameter of tip ball 5a is 0.3ϕ 0.4ϕ, in the tip of a joint 3 and providing an ink-holding pipe 4 in the rear. A valve chamber 15 is provided in the axial center of a bushing 13 and a taper-shaped or spherical ball receiving seat 14 is provided in the rear of the valve chamber 15. Necessary numbers of projected lines 19a are provided on the front circumferential wall of the valve chamber 15. A ball valve 21 closable to the ball receiving seat 14 elastically deforms the projected lines 19a and is loose-inserted so as not to be pulled out to the inside of the valve chamber 15. On one side, a barrel part 6 is formed to contact- bond the tip 5 to the tip of the joint 3 and also the bushing 13 is fixed to the axial center of the rear inner hole in a closely inserted shape. Further, the ink-holding pipe 4 is fitted to the outer periphery of a fitting cylinder part 7 in the rear of the joint 3. |
