Patent ID: 8444258

Claim:
A method of supplying a fluid to a fluid ejection head using a fluid supply mechanism that suctions the fluid from a main tank to a subtank, and supplies the fluid from the subtank through a pressure adjustment chamber to the fluid ejection head, comprising: performing a fluid refill operation for suctioning the fluid from the main tank to the subtank when the fluid ejection volume from the fluid ejection head since the last time the subtank was refilled equals or exceeds a preset reference volume; performing a fluid ejection operation of the fluid ejection head while supplying the fluid in the pressure adjustment chamber to the fluid ejection head when the fluid is not being supplied from the subtank to the pressure adjustment chamber in the fluid refill operation; and performing a fluid ejection operation of the fluid ejection head when the fluid is being supplied from the subtank to the pressure adjustment chamber by supplying the fluid in the pressure adjustment chamber to the fluid ejection head while supplying the fluid in the subtank to the pressure adjustment chamber.