Mister Softee is getting tough with impersonators this July Fourth holiday -- the "Christmas of the ice cream season," one of the firm's U.S. owners said.

With 600 trucks in 15 states, the company, which has its headquarters in Pennsylvania, is taking legal action against competitors who illegally use Mr. Softee's name, logo or jingle, said James Conway, who owns the business with his cousin, John Conway.

The Conway family founded Mister Softee in 1956, the first truck rolling through Philadelphia to hand out green ice cream on St. Patrick's Day, The Philadelphia Inquirer reported Saturday.

Last month, the U.S. Marshal's Office in New York seized two ice cream trucks from owners ordered by a federal judge to stop operating as copy cats and to reimburse the Conways $20,000 in legal fees.

The Conways decided against asking for part of the profits collected by the impostors, Jeffrey Zucker, Mister Softee's lawyer, said.

"Mister Softee is on the soft side," Zucker said. "They are not trying to put anyone out of business."