PHOSPHOR INK AND OFFSET PRINTING METHOD

PURPOSE: To obtain a printing ink which gives a printed ink film excellent in shape stability and an be completely transferred to a blanket without leaving the ink in an intaglio by using a specified vehicle, a phosphor powder and a white pigment as the constituents. CONSTITUTION: A vehicle is obtained by using, for example, 74.66wt.% red phosphor Y2 O2 S:Eu, 6.4wt.% depolymerized resin such as a polymer of i-BMA, MMA or α-MeSt and having a molecular weight of 65,000, 16.46wt.% solvent comprising diethylene glycol monobutyl ether acetate, 1.49wt.% dispersant, and 0.99wt.% white pigment (fine hydrophobic SiO2 powder). The red phosphor, the white pigment and the dispersant are further added to the vehicle, and the mixture is kneaded to give a red phosphor ink wherein the phosphor has a mean particle diameter of 4μm and which has a viscosity of 75Pa.S under a rate of shear of 2sec with a type E viscometer. The content of the phosphor powder is 70-80wt.% while the while pigment accounts for 0.2-3wt.% of the total weight of the ink. This ink is filled in the grooves of an intaglio and transferred to a silicone rubber blanket, thus effecting offset printing.