Patent ID: 7984967

Claim:
An ink jet head comprising: an elongated ink supply port extending in a longitudinal direction; a plurality of head groups, each of which comprises at least three head elements, arranged in a transverse direction crossing with the longitudinal direction, each of said head elements comprising a part of said ink supply port, a first array of ink ejection outlets for ejecting ink, ink passages for fluid communication between said ink ejection outlets of the first array and the part of said ink supply port, a second array ink ejection outlets for ejecting ink, ink passages for fluid communication between said ink ejection outlets of the second array and the part of said ink supply port, a third array of ink ejection outlets for ejecting ink, ink passages for fluid communication between said ink ejection outlets of the third array and the part of said ink supply port, and partition walls between adjacent ink passages, and a sealing tape for protecting said ejection outlets, said sealing tape being peelable in a direction from said second or third array toward said first array in each of said head elements, wherein the first array of said ink ejection outlets is disposed along one lateral side of the part of said ink supply port, and the second and third arrays of said ink ejection outlets are disposed along the other lateral side of said ink supply port, and wherein widths L 2 , measured in the longitudinal direction, of said partition walls for the first array of said ink ejection outlets are greater than widths L 1 , measured in the longitudinal direction, of said partition walls for the second and third arrays of said ink ejection outlets.