Aqueous ink, aqueous ink set, ink cartridge, ink-jet recording apparatus, ink-jet recording method, and image-forming method

Abstract

An aqueous ink comprises water, a water-insoluble coloring material, and plurality of water-soluble organic solvents and the plurality of water-soluble organic solvents including a good medium or good mediums for the water-insoluble coloring material and a poor medium or poor mediums for the water-insoluble coloring material. The ratio of the content of the poor medium and the content of the good medium is in a specific range. A water-soluble organic solvent showing the maximum Ka value out of respective Ka values of the plurality of water-soluble organic solvents is the poor medium. When the aqueous ink is in contact with a specific reaction liquid, the dissolution state or dispersed state of the water-insoluble coloring material in the ink is made unstable. As a result, an image which has a sufficiently large area factor even with a small amount of ink droplets and is excellent in image density, bleeding resistance, and fixability can be obtained. In addition, the aqueous ink is excellent in storage stability.

Description

[0001] This application is a continuation of International Application No. PCT / JP2005 / 012277, filed Jun. 28, 2005, which claims the benefit of Japanese Patent Application Nos. 2004-190555 filed Jun. 28, 2004, and 2004-190573 filed Jun. 28, 2004. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an aqueous ink and an aqueous ink set each containing a water-insoluble coloring material. More specifically, the present invention relates to a recording method and a recording apparatus each using an ink-jet recording system; and an aqueous ink suitable for an image-forming method. [0004] 2. Related Background Art [0005] Ink containing, as a coloring agent, a water-insoluble coloring material such as a pigment (pigment ink) has been conventionally known to provide an image excellent in fastness properties such as water resistance and light resistance. Various techniques have been recently proposed for the purpose of increasing the image den...

AI Technical Summary

Benefits of technology

[0015] In view of the above, the inventors of the present invention have made various studies to provide aqueous ink which can achieve both of image properties requested for an image to be formed on plain paper (a high image density, good bleeding resistance, and excellent fixability) and image properties requested for an image to be formed on a glossy recording medium having surface gloss (high gloss); and is excellent in storage stability. As a result, they have found that, depending on the properties of a water-insoluble coloring material and a water-soluble organic solvent in ink, the rate of flocculation of the water-insoluble coloring material and the formed state of an flocculate after the application of the ink to a recording medium tend to vary completely.

[0016] Accordingly, an object of the present invention is to provide an aqueous ink to be used for an image-forming method including the step

Problems solved by technology

This finding means that each of the above techniques requires an increased amount of ink to be applied as compared to that of conventional pigment ink obtained by dispersing a pigment by means of a polymer dispersant or the like for obtaining the same image density, and each of the above techniques is susceptible to improvement in this respect.

However, when the permeability of ink is improved, the ink permeates into not only the surface of a recording medium but also the depth direction of the recording medium, so a sufficient image density may not be obtained.

As a result, they have revealed that, when a coloring material is present in ink in a high concentration, a large amount of excessive coloring material is present on the surface of a recording medium, or dots having visually different shapes are formed, and that a waste colorin

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