According to the New York Post, Ozzy Osbourne has filed a lawsuit against his BLACK SABBATH bandmate Tony Iommi, claiming that Iommi illegally took sole ownership of the band's name in a filing with the U.S. Patent and Trademark Office.

Osbourne is suing Iommi for a 50 percent interest in the "Black Sabbath" trademark, along with a portion of Iommi's profits from use of the name.

The Manhattan federal court suit also charges that Osbourne's "signature lead vocals" are largely responsible for the band's "extraordinary success," noting that its popularity plummeted during his absence from 1980 through 1996.

Ozzy's suit follows one filed by Iommi in December 2008 against Live Nation. In that filing, Iommi claims the concert giant sold merchandise bearing the band's logo, despite the 2006 expiration of a merchandising deal, reportedly worth nearly $80 million. Soon after that agreement concluded, Iommi reclaimed the band's trademark.

Iommi's suit argues Live Nation continued to sell more than 100 items of merchandise featuring the band's likeness, name and logo, despite the receipt of cease-and-desist orders from the guitarist's camp. Iommi's suit seeks damages in the amount of three times the profits from the merchandise sales, plus a halt to the BLACK SABBATH product sales.

Iommi and Geezer Butler have both said some less than kind things about working with Osbourne in a new interview with Decibel magazine. The pair recently completed a new studio album as HEAVEN & HELL, the post-Ozzy version of SABBATH featuring vocalist Ronnie James Dio, and Butler said that working with Dio was much easier than Osbourne. He explained, "Ronnie's a songwriter in his own right -- he's got tons of ideas. Whereas Ozzy . . . in the old days, he'd come up with a vocal line and I'd write the lyrics. Ronnie is 100 percent involved in both the musical side and the vocal side, and he writes his own lyrics as well."

Butler added that Osbourne didn't take him seriously as a songwriter, saying, "If we were with Ozzy and I came in with the killer riff of all time, Ozzy wouldn't even think of doing it because I'm not the guitarist and that's the way he thinks . . . That's why it was so bloody hard to write anything."

Butler said about HEAVEN & HELL's debut CD, "The Devil You Know", "If we'd written this album with Ozzy, we'd still be working on the first track."

Iommi added that there was a sharp difference between the singers live as well, saying, "It was great being with Ozzy on the road . . . but with Ronnie it's a lot different, because we go out and we know exactly what we're gonna be doing. With Ozzy, we didn't really know. It was touch and go sometimes on some of those early shows, whether he was gonna turn up, if he'd be able to sing, if his voice was gone, or what. We'd have to cancel shows, which Geezer and myself really hated. But with Ronnie, we've never canceled a show."