Patent ID: 9180680
Filing Date: 2015-11-10
Classification: B41J,C09D

Abstract:
1. An ink jet recording method comprising: an ejecting step of ejecting a black ink and at least one water-based color ink from a recording head to a plain paper provided as a recording medium, wherein the black ink comprises water, water-soluble organic mediums, and a water-insoluble coloring material, wherein the water-soluble organic mediums comprise at least one good medium to the water-insoluble coloring material and a plurality of poor mediums to the water-insoluble coloring material, wherein the total amount A (% by mass) of the good medium or good mediums in the black ink and the total amount B (% by mass) of the poor mediums in the black ink are in a ratio A:B of from 10:5 to 7:9 both inclusive, wherein at least one of the plurality of poor mediums is selected from the group consisting of diethylene glycol, polyethylene glycol, and 2-pyrrolidone, wherein the water-insoluble coloring material is a self-dispersing pigment having at least one hydrophilic group attached onto a surface of a pigment particle via another group of atoms, wherein the black ink contains no resin dispersant, wherein one of the plurality of poor mediums shows a Ka value determined by the Bristow method which is the largest among the Ka values of all the water-soluble organic mediums in the ink, wherein the recording head comprises an ejection port for the black ink and an ejection port for the at least one water-based color ink, and wherein the ejecting step comprises the steps, in the following order, of: (a) forming a black image in a predetermined region of the recording medium by ejecting the black ink from the ejection port for the black ink, while scanning the recording head in a direction that is perpendicular to a direction of conveying the recording medium; (b) conveying the recording medium; and (c) forming a color image in the predetermined region of the recording medium by ejecting the at least one water-based color ink from the ejection port for the color ink, while scanning the recording head in the direction that is perpendicular to the direction of conveying the recording medium.