Patent ID: 7060740

Claim:
A clear ink composition, which contains polymer fine particles, and does not contain a colorant or contains a colorant in an amount of not more than 0.4 wt % such that the ink composition is clear, wherein said polymer fine particles are polymer fine particles of at least one type selected from the group consisting of (i) sulfonic acid group-containing polymers, (ii) modified polypropylene emulsions, (iii) copolymers obtained by polymerizing, in the presence of an alcoholic hydroxyl group-containing water-soluble macromolecular compound or a copolymerizable surfactant, an ethylenic unsaturated carboxylic acid monomer and another monomer copolymerizable therewith, and (iv) emulsified resins having a particle diameter of at least 70 nm, wherein said polymer fine particles comprise the modified polypropylene emulsions which are obtained by modifying a polypropylene having a weight average molecular weight Mw in a range of 1,000 to 50,000 inclusive with an unsaturated carboxylic acid or an anhydride thereof, and then dispersing the modified polypropylene in the presence of a basic compound and an emulsifier.