ALEXANDRIA, Va., Dec. 2 -- United States Patent no. 12,485,669, issued on Dec. 2, was assigned to Seiko Epson Corp. (Tokyo).
"Head unit and liquid ejection apparatus" was invented by Asami Okamoto (Nagano, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A head unit includes a piezoelectric element displaced according to a driving signal to cause a liquid to be ejected, a driving signal generation unit that generates the driving signal, a residual vibration signal generation circuit that outputs a change in an electromotive force of the piezoelectric element according to residual vibration, in a pressure chamber in communication with a nozzle, that occurs after supply of the driving signal, as a residual...