Patent ID: 6905199

Claim:
A method of injecting ink into an ink cartridge for an ink jet recording device having a recording head, the method comprising the steps of: providing the ink cartridge comprising: a container including: a lower section ink chamber; an upper section ink chamber; an ink supply port, disposed on a bottom wall of the container, for supplying ink to the recording head; an ink suction passage fluidly connecting the lower section ink chamber to the upper section ink chamber, and having an upper end opening disposed proximate a bottom of the upper section ink chamber and a lower end opening disposed proximate a bottom of the lower section ink chamber; a first ink injection port formed through the bottom wall of the container, opened at the bottom of the lower section ink chamber, and facing the lower end opening: a second ink injection port formed through the bottom wall of the container, and opened at the bottom of the lower section ink chamber; an ink flow passage fluidly connecting the upper section ink chamber to the ink supply port; and an air communication passage for fluid communication with the lower section ink chamber and the ambient atmosphere; a differential pressure valve having a membrane member, which is disposed in the container and disposed within the ink flow passage; and an air communication valve disposed in the container and disposed within the air communication passage; injecting ink from the lower end opening through the ink suction passage and the upper end opening into the upper section ink chamber using the first ink injection port.