Patent ID: 7673969

Claim:
An assembly for depositing droplets on a substrate during relative motion of the assembly and the substrate along a process direction, the assembly comprising: a first printhead module and a second printhead module contacting the first printhead module, each of the printhead modules including an array of nozzles through which fluid droplets can be ejected, wherein each nozzle in the first printhead module's nozzle array is offset with respect to a corresponding nozzle in the second printhead module's nozzle array in a direction orthogonal to the process direction, and wherein the first printhead module comprises at least one alignment datum that registers with a corresponding alignment datum on the second printhead module, the alignment datum of the first printhead module comprising a precision surface offset from an adjacent region of the first printhead module, and the precision surface being smoother than a surface of the adjacent region of the first printhead module.