Patent ID: 8057017

Claim:
An ink jet head comprising: a silicon substrate on a front side of which an energy generating element is provided for generating energy for ejecting ink and in which a plurality of ink supply ports for supplying the ink to said energy generating element is provided; ink ejection outlets; and a flow path formation member for forming ink flow paths for communicating said ink ejection outlets and said ink supply ports with each other, wherein said ink supply ports have such a cross-sectional shape that a width of each of said ink supply ports, measured in a direction parallel with the front side, increases to a position of a predetermined depth from an opening of each of said ink supply ports at a back side of said silicon substrate and then decreases toward the front side of said silicon substrate, so that at the position of the predetermined depth, said ink supply port has a maximum width, and wherein the predetermined depths of adjacent ink supply ports are different from each other.