US Patent 7484833 Droplet ejector and ink-jet printhead using the same

In a droplet ejector and an ink-jet printhead using the same, the droplet ejector includes a fluid path through which a fluid moves, a nozzle being formed on one end of the fluid path, a volumetric structure formed in the fluid path, the volumetric structure being sensitive to an external stimulus and being capable of varying in size to eject a droplet of the fluid through the nozzle, and a stimulus generator, which applies a stimulus to the volumetric structure to vary a size of the volumetric structure.