Patent ID: 8201925

Claim:
An ink jet print head comprising: a common liquid chamber formed on a first surface of a print head board; plural arrays of nozzles; plural arrays of ink supply ports through which ink is supplied from the common liquid chamber to the nozzles; and heating resistors installed on a second surface, opposite the first surface, of the print head board, the nozzles capable of ejecting ink from respective ejection openings by energizing the heating resistors, wherein the plural nozzle arrays include a first nozzle array situated on an end portion region of the common liquid chamber and a second nozzle array situated on a central region of the common liquid chamber, wherein the plural ink supply port arrays include a first ink supply port array formed along at least one nozzle array and situated on the end portion region of the common liquid chamber and a second ink supply port array situated on the central region of the common liquid chamber, wherein either the first nozzle array or the second nozzle array is situated between the first ink supply port array and the second ink supply port array, and wherein a heat resistance of a portion of the print head board situated between the ink supply ports in the first ink supply port array is smaller than a heat resistance of a portion of the print head board situated between the ink supply ports in the second ink supply port array.