Patent ID: 8057019

Claim:
A liquid ejection apparatus comprising: an ejection head including a nozzle in which liquid is ejected through the nozzle; a plurality of cartridges that retain the liquid and supply liquid to the ejection head; and a switching mechanism that switches liquid to be supplied to the ejection head from a plurality of types of liquids supplied from the cartridges, the switching mechanism including: a body having a communication passage in communication with the ejection head; a first diaphragm chamber and a second diaphragm chamber that communicate with each other through the communication passage and located facing each other; a first diaphragm and a second diaphragm arranged in the first diaphragm chamber and the second diaphragm chamber, respectively, the first diaphragm and the second diaphragm each being capable of opening and closing the communication passage; and an operation mechanism provided in the communication passage, the operation mechanism including: a first operation end and a second operation end that operate the first diaphragm and the second diaphragm, respectively, when the communication passage is opened to allow communication between the ejection head and at least one of the first and second diaphragm chambers; and an urging member that urges the first and second operation ends in a direction in which the communication passage is opened by the first and second diaphragms, wherein the switching mechanism has a switch operating portion that switches an open/closed state of the communication passage by pressing the first diaphragm or the second diaphragm to operate the operation mechanism, wherein when the switching operating portion does not press the first diaphragm and the second diaphragm, the first and second chambers communicate with the ejection head, wherein the body includes: a first circumferential portion arranged around one of a pair of openings of the communication passage and facing the first diaphragm; and a second circumferential portion arranged around the other opening of the communication passage and facing the second diaphragm, wherein the switching mechanism includes: a first urging member that presses the first diaphragm against the first circumferential portion to seal the communication passage; and a second urging member that presses the second diaphragm against the second circumferential portion to seal the communication passage, and wherein urging force of the urging member of the operation mechanism is set to a value greater than urging force of the first urging member of the switching mechanism and also greater than urging force of the second urging member of the switching mechanism.