| 摘要 |
PROBLEM TO BE SOLVED: To provide a water-based ink which can improve wettability of a pen core, wherein an ink dripping phenomenon from a pen point is not produced by satisfying both ink storage nature and ink recovery nature accompanying a pressure change inside a writing utensil, ink ejection nature from a pen point is prevented from being unstable, and further thinness or break in handwriting is prevented from being caused, in a water-based ink applied to a writing utensil equipped with a pen core of a synthetic resin; and to provide a direct liquid type writing utensil applied with the same.SOLUTION: The water-based ink composition for a direct liquid type writing utensil is built in a direct liquid type writing utensil which guides an ink to a pen point through a comb groove-like pen core configured by arranging at a shaft core, an ink induction core for guiding the ink to a pen point from an ink storage unit, wherein a surface tension of the water-based ink is at most 30 mN/m, and a contact angle of the water-based ink to a plane part of a disk object of a pen core is at least 30°. In addition, the direct liquid type writing utensil which builds in the ink is disclosed. |
