US Patent 7264332 Inkjet head and nozzle plate of inkjet head

An inkjet head includes plural nozzles that eject ink. The nozzles are arranged so that (a) the nozzles are arranged in a first direction on an ink ejection surface to form a plurality of rows parallel to one another; and (b) when the nozzles are projected from a second direction, which is parallel to the ink ejection surface and perpendicular to the first direction, onto a virtual straight line extending in the first direction, projective dots of the nozzles are arranged at equally spaced intervals on the virtual straight line. A spatial frequency, which is determined based on an appearance interval of a most-distant adjacent projective dot pair in the first direction, is lower than a spatial frequency corresponding to a peak value of a visual transfer function.