SAN FRANCISCO — Susman Godfrey on Wednesday filed suit against Apple Inc. on behalf of a Japanese company that says the tech giant ripped off the trademark for “Animoji” when it announced a feature for the moving graphics at last month’s iPhone X launch.

Emonster k.k., owned by a U.S. citizen living in Japan named Enrique Bonansea, alleges that Bonansea came up with the term “ANIMOJI” in 2014 and registered it at the U.S. Patent and Trademark Office the following year. He’s been using the name to market an app for moving emojis in Apple’s own app store since 2014, according to the complaint.