| 摘要 |
PROBLEM TO BE SOLVED: To expand the selection range for ink materials by a method wherein the volume of air bubbles is made larger by a vacuumized atmosphere, and the specific gravity difference with a liquid part is further expanded, and the removal of bubbles is performed by a weaker centrifugal force. SOLUTION: Invisible air bubbles in a ball-point pen, further speaking, in an ink 20 and in an ink following body, are expanded by vacuumization, and removed to the outside of a system. Therefore, the removal of air bubbles theoretically can be performed by a weaker centrifugal force than a case of a normal pressure if the atmospheric pressure is lower than a normal pressure, but the pressure of the atmosphere is preferable to be 0.5 atmospheric pressure or lower. Under this atmosphere, air bubbles become an approx. twice larger volume, and the specific gravity difference between a liquid part and the air bubbles becomes roughly twice larger as well. Further speaking, it is preferable to be 0.2 atmospheric pressure or lower. Especially, when a water-soluble ball-point pen is built up, caution is required for an excessive reduction of the atmospheric pressure. The boiling point for water under 0.2 atmospheric pressure is approx. 60 deg.C, and even by a temperature ascent which is generated by a friction or the like between a centrifugal machine and air, as long as the machine is not continuously used, the ink 20 does not boil, but at 0.01 atmospheric pressure or lower, the boiling point of water is lower than 10 deg.C. |
