US Patent 7513600 Liquid droplet discharge head and image forming apparatus

The liquid droplet discharge head comprises: a plurality of nozzles which discharge liquid droplets onto a recording medium, wherein the nozzles are arranged two-dimensionally in a main scanning direction perpendicular to a conveyance direction in which the recording medium is conveyed relatively with respect to the liquid droplet discharge head, and a sub-scanning direction which coincides with the conveyance direction, in such a manner that: at least a portion of dots formed by the droplets deposited on the recording medium from the nozzles overlap mutually in the main scanning direction; and with respect to a first nozzle and a second nozzle which discharge droplets to form mutually adjacent dots in the main scanning direction on the recording medium, and with respect to a third nozzle which is adjacent to the first nozzle in the sub-scanning direction, positions of the first nozzle and the second nozzle are separated in the sub-scanning direction by at least a distance equal to a multiple by an integer that is at least two, of a distance between the first nozzle and the third nozzle in the sub-scanning direction, and positions of the first nozzle and the third nozzle are separated in the main scanning direction by at least a distance equal to a maximum dot diameter formed by the liquid droplets discharged onto the recording medium from the first nozzle and the third nozzle.