US Patent 7641300 Liquid ejection head and image forming apparatus

The liquid ejection head has an ejection unit which includes: a nozzle ejecting a droplet of liquid; a pressure chamber connected to the nozzle; a displacement generating device which changes a volume of the pressure chamber; and a supply flow channel which is connected to the pressure chamber and supplies the liquid to the pressure chamber, wherein a resonance frequency f (kHz) of the ejection unit and an ejection speed v (m/s) of the droplet ejected by the nozzle satisfy a following relationship: f>31×v+80.