ALEXANDRIA, Va., Dec. 2 -- United States Patent no. 12,486,414, issued on Dec. 2, was assigned to MITSUBISHI PENCIL COMPANY Ltd. (Tokyo).
"Composite colored particle" was invented by Kosuke Ogura (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A composite colored particle may include a resin particle carrying a positive electric charge on a particle surface, a colored particle carrying a negative electric charge on a particle surface, and a low-density particle, the colored particle and the low-density particle forming a composite with the resin particle through Coulomb force. A water-based ink composition may contain such composite colored particles dispersed in a water-based medium. A writing instrum...