Patent ID: 7615583

Claim:
A method for producing a radiation-curable ink, comprising the steps of: (a) adding a pigment to a diluent, the diluent comprising at least one component selected from the group consisting of a resin, a dispersant and a first polymerizable compound, in a vessel to obtain a pigment mixture, a weight ratio of the pigment being 20 to 95 weight % based on the total weight of the pigment mixture; (b) dispersing the pigment mixture to obtain a colorant dispersion; (c) adding a second polymerizable compound and a polymerization initiator to the colorant dispersion to obtain a radiation-curable ink precursor, provided that the first polymerizable compound and the second polymerizable compound may be the same or different than each other; (d) adjusting a content of water in the radiation-curable ink precursor to be not more than 2.5% weight % based on the total weight of the radiation-curable ink precursor; and (e) dispersing the radiation-curable ink precursor to obtain a radiation-curable ink having a viscosity of 6 to 500 mPa·s measured at 25° C.