Patent ID: 7938497

Claim:
An ink jet printer, comprising: an ink jet head comprising an ink passage and a nozzle communicated with the ink passage; a sub ink tank communicated with the ink passage of the ink jet head, the sub ink tank being elastically deformable; a carriage on which the ink jet head and the sub ink tank are mounted, the carriage capable of moving; a main body housing the ink jet head, the sub ink tank, and the carriage, the main body comprising a space for housing a main ink tank that is to be communicated with the sub ink tank; an actuator capable of performing a predetermined action such that the actuator applies a pushing force to the sub ink tank and releases the pushing force after applying the pushing force in a state where the main ink tank is communicated with the sub ink tank; an ink quantity detection device that detects whether an ink quantity within the sub ink tank is less than a first value; and a controller that controls the actuator such that the actuator performs the predetermined action in a first case where the ink quantity within the sub ink tank is less than the first value, wherein the controller controls the actuator such that the actuator performs the predetermined action in a second case where the ink quantity within the sub ink tank is more than the first value and a predetermined condition is satisfied; wherein the pushing force applied to the sub ink tank by the actuator in the first case is greater than the pushing force applied to the sub ink tank by the actuator in the second case.