Apple Inc. sued companies it said are selling unauthorized electronic accessories such as chargers, speakers and cables for the iPod music player, iPhone and iPad tablet computer.

“Many are of inferior quality and reliability, raising significant concerns over compatibility with and damage to Apple’s products,” Apple said in the complaint, citing a user comment that a charger from one of the companies drained his iPod rather than replenishing the battery.

Apple said it has a program called “Made for iPod” under which manufacturers can get a license to sell accessories for the devices. The unauthorized products are infringing as many as 10 patents and violating Apple’s trademarks, the Cupertino, California-based companies said in the filing.

The complaint, filed July 22 in federal court in San Francisco, identifies six sellers based in California and one in Washington and said Apple could name as many as 20 additional companies. Calls or e-mails to five of the named companies weren’t immediately returned and contact information for two companies couldn’t be obtained.

Apple sold 3.27 million iPads, 8.4 million iPhones and 9.41 million iPods in the quarter ended June 26, the company said in its third-quarter earnings report on July 20.

In November, Apple sued a California company it said was selling knockoff power adapters for the MacBook laptop computer. The company agreed to a court order that it stop selling the products.

(Source: Bloomberg News)