Patent ID: 8449077

Claim:
A droplet ejection head, comprising: a plurality of nozzles which eject droplets of liquid; a plurality of pressure chambers which are filled with the liquid and connected respectively to the nozzles; a plurality of drive elements which are arranged correspondingly to the pressure chambers, the drive elements applying pressure to the liquid inside the corresponding pressure chambers; a plurality of individual supply channels which are connected respectively to the pressure chambers, the liquid being supplied to the pressure chambers through the individual supply channels; a plurality of individual recovery channels which are connected respectively to the pressure chambers, the liquid being recovered from the pressure chambers through the individual recovery channels; a plurality of common supply channels which are connected to the individual supply channels and supply the liquid to the individual supply channels, respectively; and a plurality of common recovery channels which are connected to the individual recovery channels and recover the liquid from the individual recovery channels, respectively, wherein: the droplet ejection head has a plurality of droplet ejection units, each of the droplet ejection units including one of the nozzles, one of the pressure chambers which is connected to the one of the nozzles, one of the drive elements which is arranged correspondingly to the one of the pressure chambers, one of the individual supply channels which is connected to the one of the pressure chambers, and one of the individual recovery channels which is connected to the one of the pressure chambers; and in each of the droplet ejection units, a diameter Dn (μm) of the one of the nozzles, a flow channel resistance R 1 (Ns/m 5 ) of the one of the individual supply channels and a flow channel resistance R 2 (Ns/m 5 ) of the one of the individual recovery channels satisfy: 3.247×10 15 exp(−0.1717 Dn )≦ R 1≦3.278×10 15 exp(−0.1456 Dn ); and 3.247×10 15 exp(−0.1717 Dn )≦ R 2≦3.278×10 15 exp(−0.1456 Dn ).