Patent ID: 8430486

Claim:
An ink tank which is provided with pigment ink containing pigment particles and a solvent and an ink reservoir storing the pigment ink, the ink tank comprising: a first electrode disposed on one of side surfaces defining the outside of the ink reservoir; and a second electrode disposed on another one of the side surfaces of the ink reservoir opposed to the one side surface defining the outside of the ink reservoir, wherein said first electrode is thinner than said second electrode so that an electric field strength generated by applying alternating current voltage between said first and second electrodes is higher at said first electrode than at said second electrode, an end of said first electrode is thinner than the other end thereof so that the electric field strength increases from the end of said first electrode toward the other end thereof, and hereby, the pigment particles dielectrically polarized by the alternating current voltage applied between said first and second electrodes move to where the electric field strength is higher.