Canon Kabushiki Kaisha

Akiko Yasuda

Masashi Ogasawara

Fumiaki Fujioka

Souichi Nagai

Keigo Gouda

Tomonari Watanabe

The present invention provides an ink that can achieve image characteristics for recording an image having excellent optical density, bleeding resistance, and white blur resistance and also can achieve reliability that provides excellent sticking resistance to a recording head. The ink is one for ink jet containing a first pigment and second pigment. The first pigment is a self-dispersible pigment to a surface of a particle of which a first functional group containing a phosphonic acid group is bonded. The second pigment is a self-dispersible pigment to a surface of a particle of which a second functional group not containing a phosphonic acid group but containing an anionic group other than the phosphonic acid group, and further containing another atomic group is bonded. The introduced amount of the functional group of the second pigment is 0.25 mmol/g or more.

Ink, ink cartridge, and ink jet recording method

Provided is an ink for ink jet including a first pigment and a second pigment. Each of the first pigment and the second pigment comprises a self-dispersible carbon black in which a functional group containing two phosphonic acid groups is bonded to a particle surface. The average particle size of the first pigment is smaller than the average particle size of the second pigment. The introduced amount of the functional group of the first pigment is higher than the introduced amount of the functional group of the second pigment.

Disclosed herein are an ink containing a self-dispersible pigment and a salt, wherein the self-dispersible pigment is a pigment to the surface of a particle of which a functional group containing at least a group having a hydrogen bonding property and two phosphonic acid groups is bonded, counter ions of the two phosphonic acid groups containing one of Kand NH; the salt is constituted by combining at least one cation of Kand NHwith at least one anion selected from the group consisting of Cl, Br, I, ClO, ClO, ClO, ClO, NO, NO, SO, CO, HCO, HCOO, (COO), COOH(COO), CHCOO, CH(COO), CHCOO, CH(COO), PO, HPOand HPO; a cation concentration in the ink is 0.04 mol/L or more; and the viscosity of a liquid obtained by evaporating 15% by mass of the ink is less than 3.5 mPa&#xb7;s at 25&#xb0; C.

Ink, ink cartridge and ink jet recording method

An ink jet ink including a self-dispersible pigment, a salt, a polyoxyethylene alkyl ether and a water-soluble organic solvent. The self-dispersible pigment is a pigment to a surface of a particle of which a functional group containing at least a phosphonic acid group is bonded, the introduced amount of the functional group bonded to the self-dispersible pigment is 0.10 to 0.33 mmol/g. The salt is constituted by combining a specific cation with a specific anion. The value (Concentration of anion)&#xd7;(Valence number of anion) of the salt in the ink is 0.005 to 0.06 mol/L. The water-soluble organic solvent includes glycerol, the content of which in the ink is 35% to 78% by mass based on the total content of the water-soluble organic solvent in the ink.

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Kawasaki, Japan

Akiko Yasuda