US Patent 7905578 Liquid ejection head and liquid ejection device

A liquid ejection head which can fly a minute high viscosity droplet with high precision by a low drive voltage in electric field assist system which exhibiting excellent maintainability such as cleaning. The liquid ejection head (2) comprises a nozzle plate (4) provided with a nozzle (5) having a liquid supply opening (9) for supplying a liquid (L), an ejection opening (11) for ejecting the liquid (L), and a liquid supply passage for supplying the liquid (L) from liquid supply opening (9) to the liquid ejection opening (11), a cavity (20) for storing the liquid (L), a pressure generating means for generating pressure in the cavity (20), and an electrostatic voltage generating means for generating an electrostatic attraction between the liquid (L) and a substrate. The liquid supply opening side of the nozzle (5) is formed of a silicon layer (41), the ejection opening side of the nozzle is formed of at least one resin layer (42) composed of thermosetting or photosensitive fluorine polymer having a volume resistivity of 1015Ω or above and a dielectric constant of 3 or less, and the diameter of the nozzle (5) on the liquid supply opening side is larger than that of the nozzle on the liquid ejection side.