Patent ID: 8820892

Claim:
An inkjet printing head substrate comprising: a first surface, a second surface, which is the backside of the first surface, on which a plurality of heat resistive elements are arrayed for ejecting ink, a recessed portion formed in the first surface, and a plurality of ink supply openings that are formed inside the recessed portion and pass through said inkjet printing head substrate, wherein in the second surface, the heat resistive elements and the ink supply openings are alternately arrayed in a predetermined direction to form an array, and a sum of respective distances along the predetermined direction between a heat resistive element located on an end side of the array and each of two ink supply openings, which are located adjacent to and at both sides of the heat resistive element located on the end side of the array, is greater than a sum of respective distances between a heat resistive element located in a central section of the array in the predetermined direction and each of two ink supply openings, which are located adjacent to and at both sides of the heat resistive element located in the central section of the array.