| 摘要 |
PURPOSE: To prevent dripping, reverse flow and straight flow of ink to improve cap-off performance or writing well. CONSTITUTION: An ink receiving tube 17 is filled with a low-viscosity oil ball- point pen ink, consisting of a solvent containing 60wt.% or more of an organic solvent having vapor pressure of 0.2mmHg (25 deg.C) or less, a colorant and an additive, and having the ink viscosity of 300mPa.S (20rpm, 25 deg.C) or less as well as the TI value (5rpm/20rpm, 25 deg.C) of 1.1 or more, and with follower, filled on the rear end surface of the ink. Upon writing, a tip end ball 12a is contacted closely to the inner rim of a ball retaining unit at the tip end of a tip 12 and a spring 16 is provided in the tip so that the contacting condition is not released upon non writing while the contacting condition is released upon writing. The follower 19 contains the contains at least one kind of a solvent selected from the group consisting of hardly volatile organic solvent and a non-volatile organic solvent, a gelling agent consisting of micrograin silica and a surface quality improving agent of silane series. |
