Patent ID: 6926398

Claim:
A liquid-feeding device comprising: a liquid reservoir for containing liquid therein; a liquid chamber connected to the liquid reservoir so that liquid in the liquid reservoir can flow down; a valve comprising an open region between the liquid reservoir and the liquid chamber and a closing member urged so as to close the open region so that the closing member is displaced so as to open the open region by the reduction in pressure of the liquid chamber due to the reduction in the amount of liquid in the liquid chamber; a fresh-air communicating hole built in the liquid reservoir for communicating with fresh air; and an air inlet tube arranged to extend from the fresh-air communicating hole toward the inside of the liquid reservoir so that when an amount of liquid in the liquid chamber is reduced, the amount of air corresponding to the amount of the reduced liquid can be brought into the liquid reservoir from the fresh-air communicating hole, wherein a bore diameter of a lower end of the air inlet tube and a water head pressure H are determined so that the meniscus holding power P of liquid at a lower end of the air inlet tube and the water head pressure H corresponding to a height from a liquid outlet, to which atmospheric pressure is applied satisfy the relationship: P>H.