PURPOSE: To obtain an inorganic pigment for coated paper, having improved ink glossiness and transperability of the paper, by treating the activated surface of the pigment having a large specific surface area with a cationic high polymer electrolyte.
CONSTITUTION: (A) 100 parts by wt. of an inorganic pigment, e.g. kaolin or BaSO 4 , which is subjected to mechanical treatment by a disperser, e.g. a high-speed turbine disperser or a pulverizer, having a powerful shearing force, to increase the specific surface area by ≥1%, preferably ≥3%, is treated with (B) 0.01W100 parts by wt. of one or more types of cationic high polymer electrolytes, e.g. an epoxy-cross linked polyamino resin, selected from water-soluble high polymers having one or more types of ammonium, sulfonium, phosphonium groups, or chronium atoms as functional groups.