BlackBerry has asked a California court to block U.S. sales of the Typo keyboard, an add-on keyboard for the iPhone that BlackBerry says is an "obvious knock-off" of the keyboards on its phones. The move, which came late Wednesday, intensifies a battle between the two companies that began in January this year when BlackBerry accused Typo of patent infringement. The lawsuit garnered considerable attention, in part because Typo was co-founded by popular U.S. radio and television personality Ryan Seacrest.