US Patent 7686431 Liquid droplet ejection head and image forming apparatus

The liquid droplet ejection head includes: a nozzle which ejects a droplet of a liquid containing microparticles; a pressure chamber which connects with the nozzle; a piezoelectric element which varies a volume of the pressure chamber; a common liquid chamber which stores the liquid that is to be supplied to the pressure chamber; and a supply passage which connects the common liquid chamber to the pressure chamber, wherein the supply passage has a plurality of supply ports through which the common liquid chamber is connected to the supply passage, the supply ports being disposed in different positions in a direction of gravitational force.