Ink jet printer capable of detecting lack of ink

摘要

An ink jet printer having an ink tank and nozzle passages for jetting ink therefrom. A through hole communicates with the ink tank and has a diameter which is sufficiently greater than the diameter of the nozzle passages so that air is introduced in the through hole when the pressure in the ink tank becomes negative due to a lack of ink therein and when the nozzle passages are still filled with ink. The air introduced into the through hole is detected so as to indicate a lack of ink in the ink tank.