Patent ID: 8267497

Claim:
A method of controlling a liquid ejecting apparatus including (a) a liquid ejecting head having a liquid supply portion through which a liquid is supplied to the liquid ejecting head, a liquid ejecting portion through which the liquid supplied through the liquid supply portion is ejected from the liquid ejecting head, a liquid discharge portion through which the liquid supplied through the liquid supply portion is discharged from the liquid ejecting head, and an internal passage including a passage from the liquid supply portion to the liquid ejecting portion through an intermediate part, and a passage extending from the intermediate part to the liquid discharge portion, and (b) a pressurizing portion configured to apply a pressure to at least one of the liquid supply portion and the liquid discharge portion, said method comprising: controlling the pressurizing portion so as to satisfy the following formulas (1) and (2), during a maintenance operation wherein the liquid supplied through the liquid supply portion is discharged from the liquid discharge portion, without a flow of the liquid through the liquid ejecting portion, − P 0 ′( R 1 +R 2 )< P 1 R 2 +P 2 R 1 <P 0 ( R 1 +R 2 ) formula (1) P 1 −P 2 >Q 0 ( R 1 +R 2 ) formula (2) wherein P 0 : meniscus-withstanding pressure of the liquid ejecting portion in a direction from a side of the liquid toward a side of an atmosphere, P 0 ′: meniscus-withstanding pressure of the liquid ejecting portion in a direction from the side of the atmosphere toward the side of the liquid, P 1 : pressure at the liquid supply portion during the maintenance operation, P 2 : pressure at the liquid discharge portion during the maintenance operation, R 1 : liquid flow resistance in a passage from the liquid supply portion to the intermediate part of the internal passage, R 2 : liquid flow resistance in a passage from the intermediate part of the internal passage to the liquid discharge portion, and Q 0 : minimum amount of liquid supplied through the liquid supply portion and discharged through the liquid discharge portion, which minimum amount is required to discharge foreign matters existing in a passage from the liquid supply portion to the liquid discharge portion via the intermediate part during the maintenance operation.