| 摘要 |
PROBLEM TO BE SOLVED: To easily form an ink passing hole with high sealing reliability at the time of closing and to eliminate clogging of a valve member in a part feeder, by forming a satin having a surface roughness of a specific numeric value range in a surface state of an elastic valve. SOLUTION: A surface of an elastic valve 8 opened in a slit-like ink passing hole 8a to be elastically deformed by pressing a rear end of a nib is formed with a satin having a roughness of 0.5 to 100 μm. The roughness of this case is represented by a mean value of depths of a protrusion and a recess in a predetermined measured length on the surface of the valve 8. Generally, the roughness of 0.5 μm or more is in the degree that fine protrusion and recess can be visually confirmed. When the roughness exceeds 10 μm, its liquid- tightness to ink is lowered to other member to provide a fear of leaking the ink. The roughness of an extremely soft elastic material like the valve 8 can be measured by forming a replica. Such a satin can be easily obtained by executing a sand blasting on an inner surface of a mold. |
