| 摘要 |
PROBLEM TO BE SOLVED: To eliminate adherence of ink ball to a tip by providing a groove at a ball retaining part. SOLUTION: A groove 2 is provided at a ball retaining part 1. A direction of the groove 2 may be longitudinal, lateral or oblique, and number of the installed balls may be arbitrary. A shape of the groove 2 is a square, triangular, circular or trapezoidal shape. Sine a size of the groove 2 similarly relates to viscosity of ink, it is desirable to decide the size in proportion to the viscosity. As a material of the part 1, an elastic material may be used. And, a ring of rubber or synthetic resin may be added to the part 1 to provide the groove 2 at the ring. If sufficient elasticity is given to the ring at the time of attaching the ring, the groove 2 can be provided horizontally to a rotating direction of the ball. Thus, leakage of ink having low viscosity can be prevented. To obtain an effect, the ring may be given, for example, with a shape of a spring. |
