Ink jet recording ink, ink jet recording ink set, recording method, recorded matter and ink jet recording apparatus

Abstract

Provided are an ink jet recording ink (IJ ink), an ink jet recording ink set (IJ ink set) and a recording method, having excellent dispersion stability and ejection stability and being capable of providing images which is free from bleeding and which is excellent in color development property and rubbing resistance. An IJ ink and I an IJ ink set having long-term storage stability are provided. Also provided are recorded matter having excellent color development property and rubbing resistance, and an ink jet recording apparatus capable of providing the same. The invention includes: an IJ ink containing a colorant of a pigment and / or dye enveloped in a polymer, and water, and containing at least one compound selected from the group consisting: of acetylene glycol surfactants, acetylene alcohol surfactants, glycol ethers and 1,2-alkylene glycols; an IJ ink set comprising a plurality of the inks; a recording method of using the ink and / or the ink set; recorded matter printed according to the recording method; and an ink jet recording apparatus having an electrostrictive unit mounted thereon and is designed so as to be capable of ejecting the ink.

Description

TECHNICAL FIELD[0001]The present invention relates to an ink jet recording ink, an ink jet recording ink set, a recording method, recorded matter, and an ink jet recording apparatus.BACKGROUND ART[0002]Ink jet recording is a method of recording letters and figures on the surface of a recording object by ejecting ink droplets onto the object through fine nozzles. For such an ink jet recording system, for example, practically employed are a method of recording letters and symbols on the surface of a recording object by converting electronic signals into mechanical ones by the use of an electrostrictive device, followed by intermittently ejecting the ink stored in a nozzle head onto the object according to the thus-converted mechanical signals; and a method of recording letters and symbols on the surface of a recording object by rapidly heating a part of the ink stored in a nozzle head and nearest to the ejecting orifices of the nozzle to cause bubbling, and intermittently ejecting the...

AI Technical Summary

Benefits of technology

[0013]A still other object of the invention is to provide an ink jet recording ink and an ink jet recording ink set, which have excellent long-term storage stability.

[0014]A still other object of the invention is to provide recorded matter having high-quality images of high printed density and excellent color development property, and having satisfactory rubbing resistance.

[0015]A further other object of the invention is to provide an ink jet recording apparatus capable of producing recorded matter having high-quality images of high printed density and excellent color development property, and having satisfactory rubbing resistance.DISCLOSURE OF THE INVENTION

[0016]The present inventors found that an ink containing: a colorant of a pigment and / or dye enveloped in a polymer; and water, and containing a specific compound has excellent properties suitable for ink jet recording ink. Specifically, it was found that the ink has good dispersion stability and ejection stability, and enables stable printing operation with no trouble of nozzle clogging for a long time, and further found that, when used in printing on recording media such as plain paper, regenerated paper and coated paper, it can be realized to form an image having good drying property of a printed image, being free from bleeding, having high printed density and excellent color development property and rubbing resistance. That is, the invention is as follows:

Problems solved by technology

However, the inks of this type are problematic in that their applicability to all kinds of paper is low.

Specifically, one problem is that the difference in the degree of bleeding depending on the kind of paper is large.

In particular, for regenerated paper that comprises many unspecific paper materials, the difference in the wettability of inks with such different paper materials constituting it has an influence on the degree of ink bleeding thereon, and, as a result, the print quality is unstable.

Another problem is that the inks of the type mentioned above take a long time until the printed area is dried.

Still another problem is that some pigment remains on the printed paper, and therefore the printed paper is deteriorated in abrasion resistance.

However, this is problematic in that it is not easy to improve the ink penetration while ensuring the pigment dispersion stability in ink.

Therefore, when the ink of the type is ejected through fine nozzles, the adsorbed dispersant drops off in case where it receives strong shear force, and the pigment dispersibility in the ink is lowered, thereby the ejection may tend to become unstable.

In addition, when the ink is stored for a long time, the dispersibility may tend to become unstable.

In such a case, however, the amount of the dispersant not adsorbed by the pigment but still dissolving in the ink increases, and therefore the ink often involves the phenomena that when used in printing plain paper or regenerated paper, it readily cause bleeding and it wets the periphery of the nozzles to readily make the ejection unstable.

In addition, in case where ink of a pigment dispersion prepared by dispersing a pigment by a dispersant such as surfactant or polymer dispersant to ensure improved penetration is used in printing on plain paper or regenerated paper, the pigment which is the colorant component therein tends to hardly remain on the surface of the fibers constituting the surface of the recording medium and, as a result, there is a tendency that the printed density is insufficient and the color development is not good.

Moreover, in general, the dispersant not originally adsorbed by the pigment but dissolving in ink, or the dispersant having dropped off from the pigment tend to increase the viscosity of the ink, and therefore the pigment content of the ink is limited in many cases.

Therefore, the ink of this type could not ensure sufficient printed density especially on plain paper or regenerated paper, and hence good color development cannot be attained and high-quality images are hardly obtained.

In addition, when ink is left in heads for a long time, its dispersion stability is deteriorated and there have been cases where the ejection of the ink from the nozzles of a printer becomes difficult.

However, inks using the colorant prepared through phase conversion emulsification or acid deposition in combination with a surfactant, as a penetrant, such as glycol ethers or acetylene glycol surfactants are still unsatisfactory especially in point of the image quality on plain paper or regenerated paper.

Therefore, it is difficult to obtain a sufficient printed density and the color development is not good.

In addition, bleeding readily occurs.

Furthermore, it tends to cause a phenomenon that the ink wets the periphery of the nozzles to readily make the ejection unstable.

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