Quiznos has filed for Chapter 11 bankruptcy protection to reduce its debt by more than $400 million. The sandwich chain said today that it voluntarily filed to reorganize to put a restructuring plan into place. Quiznos says customers won't notice. The company owns and operates only seven of the nearly 2,100 Quiznos restaurants; the rest are owned operated by franchisees and will continue operating as usual. Quiznos says the restructuring plan has been approved by its creditors, and it expects to emerge from restructuring quickly. Still, it's a far cry from the days when the chain seemed to pose a legitimate threat to Subway, notes CNNMoney. Earlier this month, Sbarro filed for bankruptcy protection, too.