Patent ID: 8657396

Claim:
An ink jet printer for printing using an inkjet head configured to eject a plurality of different types of inks, comprising: a mounting portion to which a plurality of ink tanks are detachably mountable, wherein each of the ink tanks contains an ink to be supplied to the inkjet head, and has a memory storing (a) type information indicative of a type of the ink contained in the ink tank and (b) individual information of the ink tank; a common wiring capable of electrically connecting in common with the ink tanks mounted on the mounting portion; and a controlling unit electrically connected with the common wiring and capable of communicating with the ink tanks through the common wiring, wherein the controlling unit is configured: (i) to select one of multiple pieces of type information corresponding to the different types, respectively, (ii) to send, to the common wiring, a send command for requesting one or more ink tanks having the selected type information to send individual information stored in the memory, (iii) to receive, from the common wiring, the individual information as a response to the send command, (iv) to send, to the common wiring, a non-response command for putting the ink tank having the received individual information into a non-response state during a predetermined period where the ink tank does not respond to the send command, and (v) to send, to the common wiring, the send command in the predetermined period, and to determine that at least two ink tanks having the selected type information are mounted on the mounting unit if the controlling unit receives individual information as a response to the send command from the common wiring.