Patent ID: 7841711

Claim:
An ink jet printer, comprising: a plurality of ink containers containing inks of different colors, respectively; a carriage which is movable in a moving direction and to which the ink containers are detachably mountable so that the ink containers are arranged in the moving direction; an electrical contact provided in each of the containers; a common electrical line configured to commonly electrically connect with the electrical contacts of the ink containers mounted to the carriage; a sending portion configured to send individual information corresponding to respective ones of the ink containers to the common electrical line; a light emitter provided in each of the ink containers and configured to emit light; a light receptor configured to receive the light from the light emitters; a memory provided in each of the ink containers and storing discrimination information; a controller provided in each of the ink containers and configured to receive, from the common electrical line through the electrical contact, individual information selected correspondingly to positions of the carriage with respect to the moving direction and configured to control the light emitter to emit light on the basis of the received individual information and the discrimination information stored in the memory; and a discriminator configured to discriminate properness of positions of the ink containers in the carriage, on the basis of light reception information of the light receptor provided by light emitted from the light emitters controlled by the controllers.