PURPOSE: A head of ink jet printer is provided to improve printing performance and quality by improving phenomena of backflow and droplet of discharged ink. CONSTITUTION: At least one ink separating wall(123) is protrusively formed on a nozzle plate near a nozzle hole(126) to be placed on an ink supplying passage(125) to interfere in flow of ink. An upper surface of a printed circuit board(112) and a front end of the ink separating wall are separated by a certain gap. The front end of the ink separating wall is placed above an outer boundary of a heat generating resistance body(114). An ink chamber(124) and the ink supplying passage are separated by an air bubble during most of process of ink discharge so that only ink isolated in the ink chamber is discharged.
