ALEXANDRIA, Va., Dec. 16 -- United States Patent no. 12,497,528, issued on Dec. 16, was assigned to SEIKO EPSON Corp. (Japan).
"Aqueous ink jet ink composition and recording method" was invented by Hisashi Okamura (Shiojiri, Japan), Hidehiko Komatsu (Chino, Japan) and Yasuhiro Oki (Matsumoto, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "An aqueous ink jet ink composition of the present disclosure contains a color material represented by Formula (1) below, a water-soluble organic solvent, and water. The color material represented by Formula (1) below contains two or more alkali metal ions as counterions, and the counterions include at least a sodium ion.(In Formula (1), M represents a counterion.)"
T...