US Patent 8052257 Combined ink family keying for an ink cartridge

An ink cartridge includes a single insertion key having a combined datum and keying feature, said insertion key being located on a back edge portion of the ink cartridge, the insertion key being configured to provide a pivotal reference point for insertion of the ink cartridge into the carriage. The ink cartridge also includes a single insertion slot in a bottom surface of said ink cartridge, said insertion slot configured to receive an alignment post.