The 60-year-old is seeking unspecified damages along with lost profits and a declaration saying he is a half-owner of the trademark, which Iommi registered in the US nine years ago. Osbourne recently issued a statement, asking the guitarist to "do the right thing".
"Tony, I am so sorry it's had to get to this point by me having to take this action against you," The BBC quoted him as saying. "We've all worked too hard and long in our careers to allow you to sell merchandise that features all our faces, old Black Sabbath album covers and band logos, and then you tell us that you own the copyright," he added.
Osbourne further said the band's all four original members should have an equal share to Black Sabbath's name, adding: "I hope that by me taking this first step that it will ultimately end up that way."