Patent ID: 7909449
Filing Date: 2011-03-22
Classification: B41J

Abstract:
1. An ink jet recording apparatus comprising: a plurality of inks; and a unit configured to perform a recovery operation by suction of inks from a plurality of ink ejection portions using suction caps, wherein the plurality of inks constitute an ink set including a combination of at least a first ink and a second ink, the first ink containing (i) a self-dispersion pigment having at least one hydrophilic group directly or through another atomic group bonded to the surface of the pigment, and (ii) ammonium ions, the second ink containing (i) a pigment, (ii) a polymer having an acid value of 160 mg KOH/g or less, and (iii) alkali metal ions, wherein the suction caps used in the recovery operation are individually respectively provided for each of the ink ejection portions for the first ink and the second ink so as to prevent a deflection phenomenon caused by precipitation of the polymer in the vicinity of ejection orifices for the first ink, and wherein the ratio of the ammonium ion concentration (mol/L) in the first ink to the alkali metal ion concentration (mol/L) in the second ink is greater than or equal to 0.33.