WRITING INSTRUMENT AND METHOD OF MANUFACTURING THEREOF

摘要

A writing instrument having a free-to-move slide plug housed in an ink reservoir thereof, wherein a liquid film is placed in a gap (G) formed between the slide plug (11) and the inner peripheral surface of the ink reservoir (2) to keep them in a virtually non-contact relation, only a viscous drag of the liquid film is acting as a moving resistance of the slide plug (11) which is virtually reduced to zero and the slide plug (11) has a smaller specific gravity than the ink (10) to give it buoyancy, thereby preventing the slide plug (11) in an upright posture from undesirably sinking into the ink.