| 摘要 |
PROBLEM TO BE SOLVED: To make the motion of a valve body smooth and make a writing smooth, by forming a valve receiving contact section of the valve body into a sphere, and setting a projection area of a void section which is formed by projecting the valve body and the void section on a plane which is orthogonal to the ink flowing direction at a specified area. SOLUTION: A valve body is a sphere made of a raw material which is hard to rust, and has a weight of a certain degree such as stainless steel and ceramic. Also, for a valve receiver, e.g. six kerves (void section) 51 having a rectangular cross section are radially provided. Then, a projected area of the void section which is not covered by the valve body by projecting the valve body and the void section 51 on a plane which is orthogonal to the axis, is set at 0.035 mm2 or higher. That is, when it is taken that the width of the kerf 51 is GW, the depth is GH, the length is GL, the diameter as a whole body is OD, the quantity is (n), and the diameter of the valve body is BD, GW×(OD-BD)÷2×n>=0.035 mm2 is satisfied. By this constitution, even when a water-soluble ink of which the viscosity is comparatively high is used, a blur of the ink becomes hard to occur, and the writing becomes smooth. |
