Patent ID: 8550598

Claim:
A liquid ejection head module comprising: first and second head units disposed in a first direction, each of the first and second head units having first and second rows of liquid ejecting heads that comprises a plurality of nozzles disposed in the first direction, the first and second rows of liquid ejecting heads being disposed in a second direction crossing the first direction; a first concavity and convexity on edge of the first head unit; a second convexity and concavity on edge of the second head unit, the edge of the second head unit facing to the edge of the first head unit, at least one of the liquid ejecting heads being disposed at each of the first and second convexities, wherein the first concavity and convexity and the second convexity and concavity are disposed in mating relation to one another, and the at least one of the liquid ejecting heads disposed at each of the first and second convexities are disposed in overlapping relation to one another in the second direction and wherein the first and second row of liquid ejecting heads of the first and second head units are aligned in a straight line in the first direction when the first concavity and convexity and the second convexity and concavity are disposed in the mating relation.