| 摘要 |
PROBLEM TO BE SOLVED: To obtain an ink composition which can give an image having sufficient fluorescent intensity and being excellent in scratch resistance, water resistance, or the like, by mixing a fluorescent colorant with water, a water-soluble organic solvent, and film-forming polymer microparticles. SOLUTION: It is desirable that the fluorescent colorant used is colorless to visible light and contains a colorant having a color in the visible region. It is desirable that the colorant is in a state in which it is free in the polymer microparticles and in the ink composition, that it is in a state in which it is physically mixed in the microparticles; or that it is in a state in which it is chemically bound to a polymer constituting the microparticles. It is desirable that the microparticles have the lowest film-forming temperature of 30 deg.C or below; that they are made from a polymer based on a thermoplastic polymer; that they have a single particle structure; that they have a core/shell structure composed of a core and a shell surrounding the core; and that they have a particle diameter of 0.4 μm or below. The organic solvent is desirably the one having a boiling point of 180 deg.C or above. |
