Patent ID: 8240822

Claim:
A liquid supply apparatus which supplies liquid from a liquid container containing the liquid to a recording head from which the liquid is ejected comprising: a liquid supply path which communicates the liquid container with the recording head; a liquid supply pump which pump-drives when a first flexible member constituting at least a part of an inner surface of a pump chamber is displaced such that a volume of the pump chamber is increased or decreased while a part of the liquid supply path is set as the pump chamber; a negative pressure chamber which is divided from the pump chamber by the first flexible member and of which volume can be changed; a pressure reduction unit which applies a negative pressure to the negative pressure chamber; a first directional valve which is provided at the liquid supply path between the liquid container and the pump chamber and passes the liquid in one direction toward the supply pump from the liquid container; a second directional valve which is provided at the liquid supply path between the supply pump and the liquid ejecting apparatus and passes the liquid in one direction toward the liquid ejecting apparatus from the supply pump; and a pressure adjustor which is provided at the liquid supply path between the first directional valve and the second directional valve and which increases a volume corresponding to at least a part of an increase volume compared to the predetermined volume of the liquid container when a negative pressure larger than a predetermined liquid supply pressure is applied to the negative pressure chamber.