JP2000186244A - Ink composition and color image-forming process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cyan-or secondary colored (orange or green) aqueous ink composition having a good pigment-dispersibility, color tone and weather resistance, and a printing process offering a high printing quality and a wide color-rendering range. SOLUTION: An ink composition (1) is an aqueous ink for recording which employs as a colorant an orange pigment coated with a resin, wherein the pigment is an imidazolone pigment. An ink composition (2) is an aqueous ink for recording which employs as a colorant a green pigment coated with a resin, wherein the pigment is a phthalocyanine pigment, at least a part of which is brominated. An ink composition (3) is an aqueous ink for recording which employs as a colorant a cyan pigment coated with a resin, wherein the pigment is a mixture of a phthalocyanine pigment which is not halogenated and a phthalocyanine pigment at least a part of which is brominated. A process for forming a multicolor image of 3 or more colors uses at least one of these.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a color image using an ink having a pigment coated with a resin as a colorant, and more particularly to a method for forming a colorant obtained by coating a pigment having a specific chemical structure with a resin. The present invention relates to a color image forming method for forming an image by combining ink and the ink.

[0002]

2. Description of the Related Art Many conventional recording inks, particularly aqueous inks for ink jet recording, have a drawback that they are poor in water resistance and light resistance because a water-soluble dye is used as a coloring agent. In addition, since the dye is dissolved at the molecular level, when printing on so-called plain paper such as copy paper generally used in offices, bleeding called whisker-like feathering occurs, leading to a significant decrease in print quality. .

Various pigment inks have been proposed in the past in order to improve the above drawbacks. For example, a resin-soluble pigment ink in which carbon black or an organic pigment is dispersed using a water-soluble resin as a binder and dispersant is used. Various resin-dispersed inks have been proposed in which a colorant is coated as ink, polymer latex, or microcapsules.

In order to obtain a high quality color image using pigment ink, the type of pigment used and its combination are greatly affected. For this reason, Japanese Patent Application Laid-Open No. 5-155006 discloses a color image forming method for forming an image by combining color inks containing yellow, magenta, and cyan pigments having specific color index (CI) numbers. In JP-A-5-320551, at least yellow,
There has been proposed a color ink for an inkjet printer in which a pigment exhibiting magenta, cyan, and black colors is dispersed in a non-aqueous solvent in which a resin component is dissolved. Furthermore, the present inventor has proposed a color ink for an ink jet printer in which a microencapsulated pigment exhibiting at least yellow, magenta, cyan, and black colors is dispersed in an aqueous medium in JP-A-10-52925.

[0005] Further, as described in the above publication,
As a printing method having a larger color rendering range than the color system, it corresponds to a secondary color obtained by combining yellow and magenta among colors corresponding to secondary colors obtained by combining them in addition to cyan, yellow, magenta, and black. A so-called hi-fi color using six colors of ink in which green corresponding to a secondary color obtained by combining orange, cyan and yellow is added is also known.

[0006] However, it is not easy to stably disperse pigments having excellent color purity in inks conventionally used for Hi-Fi colors, and color printing is performed using an ink in which these pigments are used as a colorant. In the case of performing, the color balance of each ink and the fading balance due to exposure to sunlight or the like greatly affected the image quality and its stability.

In a so-called microcapsule in which the surface of a pigment is coated with a resin, not only in a four-color system but also in a six-color system, it is natural that microencapsulation varies depending on each color pigment, and a microparticle having a constant particle diameter is obtained. There was a problem that capsules could not be obtained and it was difficult to maintain the dispersion stability of each color at a constant level.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink which is excellent in full-color color reproducibility, weather resistance and dispersibility, and a color image forming method using the ink. It is in.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have accomplished the present invention.

That is, the present invention relates to a recording aqueous ink using a pigment coated with a resin as a colorant, wherein the orange pigment is an imidazolone pigment, and preferably the C.I. I. Pigment Orange 36, and a green pigment is a phthalocyanine pigment which is at least partially brominated. I. Pigment Green 36
And a mixture of a non-halogenated phthalocyanine pigment and a polybrominated phthalocyanine pigment, wherein the non-halogenated phthalocyanine pigment is preferably at least C.I. I. Pigment Blue 15: 3 or 15: 4, and the polybrominated phthalocyanine pigment is C.I. I. Pigment Green 36 is provided.

The present invention also relates to a water-based recording ink using a pigment coated with a resin as a colorant, wherein the pigment is a cyan ink comprising only a phthalocyanine pigment which is not halogenated, or a phthalocyanine which is not halogenated. A cyan ink comprising a pigment and a phthalocyanine pigment at least partially brominated (hereinafter, sometimes referred to as a cyan ink containing a phthalocyanine pigment whose halogen is not halogenated as an essential component) and a quinacridone pigment. At least 3 of magenta ink and yellow ink composed of benzimidazolone pigment
A color image forming method for forming an image using color inks and a color image forming method for forming an image using at least a total of five inks of the above-described orange and green inks are provided.

In these image forming methods, by combining black ink using carbon black as a colorant, it is possible to form a full-color image with higher color reproducibility.

The cyan ink composition used in the present invention comprises:
For example, a cyan ink composition containing, as an essential component, a resin-coated non-halogenated phthalocyanine pigment as a resin-coated pigment,
When the resin-coated pigment is only a resin-coated non-halogenated phthalocyanine pigment (I)
And, consequently, both the case where the non-halogenated phthalocyanine pigment and the case where at least a part of the phthalocyanine pigment is brominated are both contained (II).

That is, as the form (II), the cyan resin-coated pigment used in the present invention is an intraparticle mixed system.
A resin-coated pigment (II-a) obtained by resin-coating a pigment mixture of a non-halogenated phthalocyanine pigment and a phthalocyanine pigment at least partially brominated, or
A resin-coated pigment (II-b), which is a mixture of a non-halogenated phthalocyanine pigment-only resin-coated pigment and an at least partially brominated phthalocyanine pigment-only resin-coated pigment, which is an interparticle mixed system. There are cases.

The cyan ink composition used in the present invention comprises:
A water-based recording ink using a cyan pigment coated with a resin as a colorant, wherein the pigment is a resin-coated pigment that is a mixture of a phthalocyanine pigment that is not halogenated and a phthalocyanine pigment that is at least partially brominated. A composition.

Another cyan ink composition used in the present invention is a cyan ink aqueous recording ink using a resin-coated pigment as a coloring agent, which is a resin-coated non-halogenated phthalocyanine pigment. And an ink composition comprising a mixture of a resin-coated pigment and a phthalocyanine pigment coated with a resin and at least partially brominated.

That is, when the cyan ink is formed by using both the phthalocyanine pigment (X) that is not halogenated and the phthalocyanine pigment (Y) that is at least partially brominated, there are the following two cases. .

1) A case where each of these pigments is previously mixed so as to have a cyan color to form a pigment mixture, and the whole is coated with a resin to be used as a resin-coated pigment. In this case,
Pigments (X) and (Y) coexist in one resin-coated pigment particle (in the case of II-a). 2) A case where each of these pigments is separately coated with a resin to obtain a resin-coated pigment of each color in advance, and these are mixed and used so as to become cyan. In this case, a mixture of the resin-coated pigment of the pigment (X) alone and the resin-coated pigment of the pigment (Y) alone is obtained (in the case of II-b).

Hereinafter, unless otherwise specified, the form (II
The preferred use form of the pigment used in both -a) and form (II-a) is common.

The cyan pigment in the color image forming method of the present invention must be a phthalocyanine pigment from the viewpoint of color tone and weather resistance. Specific examples of the phthalocyanine pigment include metal-free phthalocyanine, copper phthalocyanine or chlorinated copper phthalocyanine, and various other metal phthalocyanines. The cyan pigment is preferably selected among these from copper phthalocyanine.

The cyan pigment preferably contains a nonhalogenated phthalocyanine pigment as an essential component, and is a mixture of a nonhalogenated phthalocyanine pigment and a phthalocyanine pigment at least partially brominated. More preferably, among the above mixtures, a non-halogenated phthalocyanine pigment,
It is particularly preferred that the secondary particles contain at least a part of a brominated phthalocyanine pigment.

Non-halogenated phthalocyanine pigments include C.I. in terms of color tone and dispersibility, especially when combined with other color pigments. I. Pigment Blue 15: 3
Or, 15: 4 is more preferable. The color tone of these pigments is slightly reddish cyan, and can be toned with a green phthalocyanine pigment if necessary. However, there is no color separation, and the resin-coated pigment colorant In combination with a halogenated phthalocyanine pigment that does not impair the dispersion stability of the cyanide, and an aqueous ink for cyan recording using a pigment coated with a resin as a colorant,
As a combination of a non-halogenated phthalocyanine pigment coated with a resin and a halogenated phthalocyanine pigment coated with a resin, the halogenated phthalocyanine pigment may be at least partially brominated phthalocyanine pigment, More preferably, it is preferable to use a brominated phthalocyanine pigment having only a bromination structure without a chlorinated structural portion, particularly a polybrominated phthalocyanine pigment. C. I. Pigment Blue 15: 3 or 15: 4 in combination with C.I. I. Pigment Green 36.

That is, in a cyan color recording aqueous ink using a mixture of a non-halogenated phthalocyanine pigment, a phthalocyanine pigment at least partially brominated itself, and a pigment coated with a resin as a coloring agent, The non-halogenated phthalocyanine pigment coated with the resin and the resin-coated pigment of the resin-coated at least partially brominated phthalocyanine pigment include at least a non-halogenated phthalocyanine pigment containing at least C. . I. Pigment Blue 15: 3 or 1
5: 4, at least partially brominated phthalocyanine pigment is C.I. I. Pigment Green 36 is optimal. In this combination, the color tone can be corrected more easily than in the case of blue 15: 4 alone, which has a stronger reddish color than the original cyan color.

The magenta ink composition used in the present invention is, for example, an ink composition in which the pigment is a quinacridone pigment, and is preferably an aqueous recording ink using a quinacridone pigment coated with a resin as a coloring agent.

The magenta pigment needs to be a quinacridone pigment from the viewpoint of color tone and weather resistance. Specific examples of the quinacridone pigment include dimethylquinacridone and dichloroquinacridone. Among these, C.I. is particularly preferred in terms of color tone and dispersibility when combined with other color pigments. I. Pigment Red 122 is preferred.

The yellow ink composition used in the present invention is, for example, an ink composition in which the pigment is a benzimidazolone pigment, and is preferably an aqueous recording ink containing a benzimidazolone pigment coated with a resin as a colorant. It is.

The yellow pigment must be a benzimidazolone pigment in terms of color tone and weather resistance. Specific examples of the benzimidazolone pigment include C.I.
I. Pigment Yellow 120, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 154
C. I. Pigment Yellow 156, C.I. I. Pigment Yellow 175. Among these, C.I. in terms of color tone and dispersibility when combined with other color pigments. I. Pigment Yellow 151 is most preferred.

The black ink composition used in the present invention may be a black ink composition obtained by mixing the above three color pigments. For example, an ink composition wherein the pigment is carbon black And a recording water-based ink containing carbon black coated with a resin as a coloring agent.

The black pigment is not particularly limited, but carbon black is preferred in terms of color tone and weather resistance.

The present invention is equivalent to the above four secondary colors.
The orange ink composition and the green ink composition have the greatest features.

The orange ink composition of the present invention is an aqueous ink composition for recording using an orange pigment coated with a resin as a coloring agent, wherein the pigment is an imidazolone pigment. Examples of the orange pigment include disazo and pyrazolone-based orange pigments such as C.I. I. Pigment Orange 13, which produces a brighter orange color than C.I.
I. Pigment Orange 36 is particularly preferred.

On the other hand, the green ink composition of the present invention is a water-based recording ink using a green pigment coated with a resin as a coloring agent, wherein the pigment is a phthalocyanine pigment at least partially brominated. Things. The at least partially brominated phthalocyanine pigments include phthalocyanine pigments that are only brominated and phthalocyanine pigments that are both brominated and chlorinated. Green pigments include chlorinated phthalocyanine green pigments such as C.I. I. Pigment Green 7, which is a phthalocyanine pigment which is both brominated and chlorinated, and which provides a lighter green color. I. Pigment Green 36 is particularly preferred.

Each of the above color pigments can be used alone or in combination. If necessary, other types of dyes and pigments may be used together to form an ink to form a color image.

In order to prepare an ink using the pigment, the dispersion medium is preferably water from the viewpoint of environmental hygiene. Other components such as a dispersant, a binder resin, an organic solvent,
Although various additives such as antibacterial preservatives and stabilizers can be used, the conventional pigment dispersion using a dispersant has a small pigment dispersion stability and a narrow color reproduction range. A so-called microcapsule ink in which the so-called microcapsules are dispersed in a dispersion medium is preferable.

In the present invention, each of the cyan ink composition, the orange ink composition and the green ink composition is obtained by dispersing a microcapsule in which a pigment is coated with a resin in a dispersion medium, The ink may be substantially free of an agent and a binder resin, but all of one, two, or three of the other magenta, yellow, and black ink compositions may be pigmented. It is technically preferable to use an ink in which microcapsules coated with a resin are dispersed in a dispersion medium and substantially free of other dispersants and binder resins.

Various techniques known in the art can be applied to the microencapsulation of the pigments for obtaining the ink compositions of the six colors, respectively. The pigments used in the color image forming method of the present invention can be used. In order to obtain a highly stable microcapsule ink, the resin for coating the pigment is obtained by neutralizing at least a part of the acid groups of the synthetic resin (a) having an acid value of 50 to 280 with a base (b). The ink is preferably a self-water dispersible resin (A) in which the colored resin particles are dispersed in an aqueous medium containing water as an essential component.

A part or all of the resin coating the pigment may be cross-linked. As a means for cross-linking, a conventionally known method can be used. A method of performing polymerization, a method of dispersing a pigment and microencapsulating a synthetic resin solution containing a crosslinkable monomer, and then crosslinking the crosslinkable monomer taken into the capsule, an anionic property of the self-water dispersible resin (A) A self-water-dispersible ionomer resin (B) in which at least a part of the functional group is neutralized with a monovalent base, and at least another part of the functional group has an intermolecular cross-linked structure by ionic bonding with a polyvalent metal ion. )) To cover the pigment surface.

The acid group of the synthetic resin (a) is, for example, a carboxylic acid group, a sulfonic acid group, a sulfinic acid group, and is not particularly limited. Among them, the carboxylic acid group is generally used. Provides a good self-water dispersible resin (A).

The synthetic resin (a) may be any resin as long as it satisfies the above characteristics. Specific examples thereof include styrene or substituted styrene such as α-methylstyrene, methyl acrylate, and ethyl acrylate. At least one selected from acrylates such as esters, butyl acrylate and 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and methacrylate such as 2-ethylhexyl methacrylate Copolymers containing the above monomer units and at least one monomer unit selected from acrylic acid and methacrylic acid can be used. In particular, styrene monomers and acrylic monomers are essential monomer components of the self-water-dispersible resin (A). Acid monomer, A copolymer obtained by using the Taakuriru acid monomers, in particular constituent ratio styrene monomer 65 to 85 mole% of these essential monomer components, 5 to 15 mol% of acrylic acid monomer, methacrylic acid monomer 10
When the amount is required to be 20 mol%, the copolymer is applied to at least three ink compositions of orange, green, and cyan to obtain the dispersion stability and color stability of the pigment colorant of the present invention. It is possible to maximize color reproduction in an image forming method, and to provide excellent colored resin particles without clogging of nozzles as ink for inkjet recording.

The molecular weight range of the synthetic resin (a) is not particularly limited, but is more preferably from 1,000 to 100,000. Of course, the self-water dispersible resin (A) obtained from the synthetic resin (a) is not particularly limited as long as it forms stable colored resin particles in combination with an aqueous medium. You may mix and use two or more types simultaneously.

The method for producing the colored resin particles containing the colorant (B) by the film-forming resin (A) of the present invention is not particularly limited, but a more preferred specific example is the following method. Can be obtained at

(1) A resin coloring step in which at least a coloring agent (B) is dispersed or dissolved in a synthetic resin (a) having an acid value to obtain a solid coloring compound. (2) At least water, an organic solvent dissolving the synthetic resin (a), the base (b), and the solid coloring compound obtained in the resin coloring step are mixed, and at least a part of the resin is dissolved by dispersion. A suspension step to obtain a colorant suspension. (3) A reprecipitation step of depositing a dissolved resin component on the surface of the colorant in the colorant suspension obtained in the suspension step.

The resin coloring step (1) is a step of dispersing or dissolving at least the coloring agent (B) in the synthetic resin (a) having an acid value to obtain a solid coloring compound. In this step, the colorant (B) is converted to a synthetic resin (a) having an acid value by using a kneading device such as a roll, a kneader, or a bead mill, which is conventionally known, in the form of a solution or heated and melted.
And then uniformly dissolving or dispersing the resulting mixture into a solid kneaded product (solid colored compound).

In the suspension step (2), at least water, an organic solvent for dissolving the synthetic resin (a), a base (b), and the solid coloring compound obtained in the resin coloring step are mixed.
This is a step of obtaining a colorant suspension in which at least a part of the resin is dissolved by dispersion.

The solid colored compound obtained in the resin coloring step (1) is mixed with water, an organic solvent dissolving the synthetic resin (a) having an acid value, and a base solvent (b) as a dispersion medium. In addition, the colorant (B) is stirred from the surface of the solid colored compound by stirring so as to be uniformly dispersed.
A colorant suspension in which a synthetic resin (a) having an acid value including the following is dissolved or self-emulsified with the help of an organic solvent and a base, and in each case, at least a part of the resin is dissolved: Is obtained.

As a stirring method for obtaining a suspension, any known and commonly used method can be adopted. For example, in addition to a conventional single-shaft propeller-type stirring blade, a stirring blade having a shape suitable for the purpose or a stirring blade may be used. It can be easily suspended using a container.

In obtaining the suspension, there is no or relatively small shearing force, only by simple mixing and stirring, or when the colorant (B) is relatively easy to coagulate, in addition to that, further increase The dispersion may be further stabilized under the shearing force. As the dispersing machine in this case, a conventionally known bead mill, a high-pressure homogenizer, a beadless dispersing machine known by trade names such as a microfluidizer and a nanomizer can be used.

The reprecipitation step (3) is a step of depositing the dissolved resin component on the surface of the colorant in the colorant suspension obtained in the suspension step. "Reprecipitation" in the present invention
This does not mean that the colorant or the colorant in which the dissolved resin is adsorbed on the colorant surface is separated and settled from the liquid medium of the suspension. Therefore, what is obtained in this step is not a mere mixture in which the solid component and the liquid component are clearly separated, but the colorant in which the dissolved resin is adsorbed on the colorant surface is stably dispersed in the liquid medium of the suspension. It is an aqueous dispersion of colored resin particles.

The deposition of the dissolved resin on the surface of the colorant in the colorant suspension in the suspension step (2) is performed, for example, by adding the resin to the colorant suspension in which the resin is dissolved at least partially. It can be easily carried out by adding water or an aqueous medium functioning as a poor solvent and / or by removing the organic solvent from the colorant suspension.

From the aqueous dispersion of colored resin particles thus obtained, the co-existing organic solvent is further removed, and the stability of the colored resin particles containing the colorant (B) in the film-forming resin (A) is stabilized. To obtain an aqueous dispersion.

Further, after the step is completed, it is preferable to remove large-diameter particles by filter filtration, centrifugation or the like. The ink thus obtained is suitable for a color image forming method of the present invention, especially an ink jet recording method, as an ink having excellent full-color color reproducibility and weather resistance and excellent dispersibility.

The neutralization of the acid groups of the synthetic resin (a) with the base (b), that is, the neutralization with the alkaline neutralizing agent, requires that the water-dispersible resin be neutralized to such an extent that the resin does not dissolve in water. An alkaline neutralizer may be added in an excessive amount as long as it does not dissolve.
It is preferable to neutralize at least mol%. When the neutralization ratio is 40 mol% or more, the colored resin particles having a small particle size are obtained, and the dispersion stability is excellent.

Before the pigment is coated with the resin, the mixture is a cyan unresin-coated pigment mixture composed of a non-halogenated phthalocyanine pigment and a brominated phthalocyanine pigment at least partially, and In the case of the coated pigment, a mixture of a cyan resin-coated pigment composed of a non-halogenated phthalocyanine pigment coated with a resin and an at least partially brominated phthalocyanine pigment coated with a resin. Is more preferable.

Before the resin coating, if the pigment is a mixture of a non-halogenated phthalocyanine pigment and at least a partially brominated phthalocyanine pigment, the mixture may be halogenated. It is particularly preferable that the secondary particles are a mixture of a phthalocyanine pigment having no phthalocyanine pigment and a phthalocyanine pigment which is at least partially brominated.

In the cyan ink composition of the present invention,
In a cyan recording water-based ink which forms colored resin particles from a mixture of a non-halogenated phthalocyanine pigment and at least a partially brominated phthalocyanine pigment, and a pigment coated with a resin, In order to form colored resin particles of a non-halogenated phthalocyanine pigment coated with a resin and at least a partially brominated phthalocyanine pigment coated with a resin,
In the resin coloring step (1), both pigments are mixed and dispersed,
In the resin coloring step (1), each pigment is dispersed separately, and in the suspension step (2), a colorant suspension in which both pigments are mixed is obtained, or in the reprecipitation step (3), both pigments are mixed. The dissolved resin component may be deposited on the surface of the mixed colorant, or the aqueous dispersion of the colored resin particles separately obtained may be combined and toned.

In preparing the cyan ink composition of the present invention, as described above as a more preferable embodiment, when both pigments are mixed and dispersed in the resin coloring step (1), the final ink composition is obtained. Since the pigment serving as the core in the colored resin particles contains many secondary particles in which non-halogenated phthalocyanine pigments and primary particles of at least partially brominated phthalocyanine pigments are mixed, more uniform toning is possible. Become.

The amount of the self-water dispersible resin (A) is not particularly limited, but is preferably 0.5 to 20% by weight in the finally obtained aqueous ink.

The base (b) (alkaline neutralizing agent) includes, for example, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, and basic substances such as ammonia, triethylamine and morpholine. Alcohol amines such as triethanolamine, diethanolamine and N-methyldiethanolamine can be used.

As the organic solvent used for dissolving the resin, any organic solvent can be used as long as it dissolves the resin. For example, ketones such as acetone, dimethyl ketone and methyl ethyl ketone can be used. Solvents, alcohol solvents such as methanol, ethanol, and isopropyl alcohol; chlorine solvents such as chloroform and methylene chloride; aromatic solvents such as benzene and toluene; ester solvents such as ethyl acetate; ethylene glycol monomethyl ether; Examples thereof include glycol ether solvents such as dimethyl ether, amides, and the like.

When the resin component is an acrylic resin among these organic solvents, a combination of at least one selected from ketone solvents and alcohol solvents is preferable. The amount of the organic solvent used is not particularly limited as long as the effects of the present invention are achieved, but is preferably such that the weight ratio of the synthetic resin / the organic solvent is 1/1 to 1/20.

As an additive, if necessary, a dispersant,
A plasticizer, an antioxidant, an ultraviolet absorber, and the like may be used together with a solvent, a resin, and a colorant.

The water used in the aqueous medium mixed with the colored resin solution is preferably water of a grade equal to or higher than ion-exchanged water in order to avoid nozzle clogging when mainly used as jet ink.

In order to prevent the ink for ink jet recording from drying, it is preferable that a water-soluble organic solvent is present in the ink as a drying inhibitor. The anti-drying agent may be added to the aqueous medium during or after emulsification. Such an anti-drying agent has an effect of preventing drying of the ink at the ejection nozzle port of the ink jet, and an agent having a boiling point higher than that of water is usually used.

Examples of such an anti-drying agent include polyhydric alcohols such as conventionally known ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol and glycerin, and alkyl ethers thereof. N-methyl-2-pyrrolidone, 2-
Examples thereof include pyrrolidone such as pyrrolidone, amides, dimethyl sulfoxide, imidazolidinone, and the like. The amount of the anti-drying agent varies depending on the type.
It is appropriately selected from the range of 1 to 150 parts by weight with respect to 100 parts by weight of water. If glycerin and other anti-drying agents are used in combination,
~ 50 parts by weight are preferred.

When the ink used in the image forming method of the present invention is an aqueous ink, a water-soluble resin, a pH adjuster, a surfactant for dispersing, defoaming, and penetrating into paper, a preservative, if necessary. And an additive such as a chelating agent.

Further, in the case of the method of forming an image by an ink jet recording method, if necessary, a jet-spraying agent is used as a penetrating agent so as to have a penetrating effect in order to make the adhering ink permeate more into the paper. The indicated water-soluble organic solvents may be added.

As such a penetrant, ethanol,
Lower alcohols such as isopropyl alcohol, glycol ethers such as diethylene glycol-N-butyl ether, and the like can be used, but are not limited thereto. The amount of the penetrant used is not particularly limited as long as the effects of the present invention are achieved, but is preferably 0.1 to 10% by weight in the finally obtained aqueous ink.

These additives may be added to the aqueous medium in advance, may be added when the self-water-dispersible resin solution containing the colorant is mixed with the aqueous medium, or may be added after the mixing. However, it is preferable to avoid adding additives after the final filtration.

In the present invention, a multicolor image including superimposition of these colors is formed using at least three colors of a cyan ink composition, a magenta ink composition, and a yellow ink composition. However, when at least three colors are used, in each color recording aqueous ink using a cyan pigment coated with a resin as a colorant,
A cyan ink composition which is a mixture of a phthalocyanine pigment whose pigment is not halogenated and a phthalocyanine pigment which is at least partially brominated, a magenta ink composition comprising a quinacridone pigment, and a yellow ink comprising a benzimidazolone pigment A color image can be formed using at least the color ink composition.

Also in this embodiment, in comparison with the case where only three colors of ink are used, a better technical effect can be obtained than in the case where the conventional ink compositions of only three colors are used.

Further, in addition to the three color ink compositions, a black ink composition using carbon black as a colorant is combined, and at least four color ink compositions are combined to form an image. You can also.

In the present invention, two colors, an orange ink composition and a green ink composition, are added to the cyan ink composition, the magenta ink composition, and the yellow ink composition. Using at least five colors,
It is also possible to form a multicolor image including the superposition of these colors, but in this case, the pigment is halogenated in a recording aqueous ink using a pigment coated with a resin as a colorant. At least three colors of cyan ink, which contains no phthalocyanine pigment as an essential component, magenta ink, which is quinacridone pigment, yellow ink, which is benzimidazolone pigment, and orange pigment coated with resin as a coloring agent In the recording aqueous ink, the pigment is at least partially brominated in the orange ink composition in which the pigment is an imidazolone pigment and in the recording aqueous ink in which the green pigment coated with a resin is a coloring agent. An image can also be formed using a green color ink composition which is a phthalocyanine pigment.

In this embodiment, the conventional three-color ink compositions of only three colors are used, the three-color ink compositions of the present invention are used, or the conventional five-color ink compositions of only five colors are used. A better technical effect can be obtained than when using a product.

In the image forming method using each of the five color ink compositions of the present invention, the cyan ink composition is coated with a resin in the same manner as that which is suitable for the three color image forming method. A water-based ink for color recording using a colored cyan pigment as a colorant, a resin-coated pigment of a pigment mixture of a phthalocyanine pigment whose halogen is not halogenated and a phthalocyanine pigment which is at least partially brominated, or a resin. A water-based ink for cyan recording using a colored pigment as a colorant, comprising a resin-coated non-halogenated phthalocyanine pigment and a resin-coated at least partially brominated phthalocyanine pigment It is likewise preferred to use a cyan ink composition which is a mixture of resin-coated pigments.

In addition to the five color ink compositions, a black ink composition using carbon black as a colorant may be combined, and an image may be formed using a combination of at least six color ink compositions. , This is the optimal embodiment.

Each ink composition of the present invention can be applied to known and common ink fields, but is preferably used as an ink for ink jet recording. That is, an image can be formed from the ink composition of the present invention by using an inkjet recording method.

The recording medium used for forming an image at this time includes, for example, plain paper, resin-coated paper, surface-treated resin film, cloth and the like.

[0078]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention includes the following embodiments.

1. An aqueous ink composition for recording comprising an orange pigment coated with a resin as a coloring agent, wherein the pigment is an imidazolone pigment.

2. An aqueous ink composition for recording comprising a green pigment coated with a resin as a colorant, wherein the pigment is a phthalocyanine pigment at least partially brominated.

3. An ink composition comprising a water-based recording ink containing a cyan pigment coated with a resin as a coloring agent, wherein the pigment is a mixture of a non-halogenated phthalocyanine pigment and a phthalocyanine pigment at least partially brominated.

4. A mixture of a resin-coated non-halogenated phthalocyanine pigment and a resin-coated at least partially brominated phthalocyanine pigment in a water-based cyan recording ink using a resin-coated pigment as a colorant. An ink composition which is:

5. When the imidazolone pigment is C.I. I. 2. The ink composition according to the above 1, which is CI Pigment Orange 36.

6. The phthalocyanine pigment at least partially brominated is C.I. I. 3. The ink composition according to the above item 2, which is Pigment Green 36.

7. The non-halogenated phthalocyanine pigment contains at least C.I. I. Pigment Blue 15:
Phthalocyanine pigments selected from 3 or 15: 4 and at least partially brominated are C.I. I. Pigment Green 3
6. The ink composition according to the above 3 and 4, which is 6.

8. 8. The ink composition according to any one of the above items 3 and 7, wherein the resin-coated cyan pigment comprises secondary particles in which a non-halogenated phthalocyanine pigment and at least a part of a brominated phthalocyanine pigment are mixed.

9. The resin is a copolymer comprising a styrene monomer having a monomer ratio of 65 to 85 mol%, an acrylic acid manomer of 5 to 15 mol%, and a methacrylic acid monomer of 10 to 20 mol%. 1 above
The ink composition according to any one of claims 1 to 8, wherein

(10) In a recording aqueous ink using a pigment coated with a resin as a colorant, the pigment is a magenta ink comprising the cyan ink described in any one of (3), (4), (7), (8) and (9) above and a quinacridone pigment. A color image forming method, wherein an image is formed using at least three color inks of a color ink and a yellow ink composed of a benzimidazolone pigment.

11. Aqueous recording inks with a resin-coated pigment as a colorant, a cyan ink containing a phthalocyanine pigment whose pigment is not halogenated as an essential component, a magenta ink containing a quinacridone pigment, and a benzimidazolone pigment. 10. The ink of at least three colors of yellow ink, the orange ink of any one of the above 1 or 5, or 9;
Or a method for forming an image using the green ink described in any one of 6 and 9 above.

12. 10. A recording aqueous ink using a pigment coated with a resin as a colorant, wherein the cyan ink described in any one of the above 3 or 4 or 7 or 8 or 9, and a magenta ink made of a quinacridone pigment,
10. The ink of at least three colors of a yellow ink comprising a benzimidazolone pigment, the orange ink of any one of the above 1 or 5, and the ink of 2 or 6,
10. A color image forming method, wherein an image is formed using the green color ink according to any one of 9.

13. 11. The color image forming method according to the above item 10, wherein image formation is performed using a combination of at least four colors of ink in combination with black ink using carbon black as a coloring agent.

14. 13. The color image forming method according to the above item 11 or 12, wherein an image is formed using a combination of at least six colors of ink in combination with a black ink using carbon black as a coloring agent.

15. The quinacridone pigment is C.I. I. Pigment Red 122.
15. The color image forming method according to any one of items 14 to 14.

16. The benzimidazolone pigment is C.I.
I. Pigment Yellow 151, the color image forming method according to any one of the above 10 to 15, wherein

17. 17. The color image forming method according to any one of the above items 10 to 16, wherein the image is formed using an ink jet recording method.

The present invention includes the following preferred embodiments. 1. In the following steps, an aqueous dispersion of colored resin particles to obtain an aqueous dispersion of colored resin particles is produced. (1) Synthetic resin (a) (styrene-acrylic acid-methacrylic acid resin) having a glass transition temperature of 70 to 120 ° C. and colorant (B) (pigment) dispersed with two rolls to obtain a solid colored compound. Coloring process. (2) At least water, an organic solvent dissolving the synthetic resin (a) (methyl ethyl ketone / isopropyl alcohol), a base (b) (alcoholamine), and the solid coloring compound obtained in the resin coloring step are mixed, and dispersed and stirred. A suspension step of dispersing with a machine to obtain a colorant suspension. (3) A reprecipitation step in which water is added to the colorant suspension obtained in the suspension step to deposit a dissolved resin component on the colorant surface. 2. After the reprecipitation step (3), the solvent is removed to obtain an aqueous dispersion. 3. The obtained aqueous dispersion is gradually added to an aqueous solution of an ink adjusting agent, and after adjusting the concentration and physical properties, filtration is performed to obtain an aqueous ink for inkjet recording.

[0097]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In addition, "part" in the following examples
Represents "parts by weight".

(Example 1) C.I. I. Pigment Orange 36 and a styrene-acrylic acid-methacrylic acid resin (styrene / acrylic acid / methacrylic acid = 77/10).
/ 13; molecular weight 50,000, acid value 160, glass transition temperature 10
(7 ° C.) 20 parts of the two-roll kneaded material is added to a mixed solution of 210 parts of water, 35 parts of glycerin, 8 parts of triethanolamine, 90 parts of methyl ethyl ketone and 40 parts of isopropyl alcohol, and stirred at room temperature for 3 hours to suspend the colorant. A suspension was obtained.

While stirring the resulting suspension, a mixture of 30 parts of glycerin and 210 parts of water was added dropwise at a rate of 5 ml / min to obtain an aqueous dispersion of orange colored resin particles. A part of methyl ethyl ketone, isopropyl alcohol and water was distilled off from the obtained capsule liquid using a rotary evaporator to obtain a final aqueous dispersion of orange colored resin particles having a pigment content of 8% by mass.

50 parts of the aqueous dispersion of the colored resin particles was gradually added to 50 parts of a mixed aqueous solution containing 5% by mass of glycerin and 2% by mass of propylene glycol propyl ether while stirring, and the mixture was filtered using a 0.5 μm filter. The recording water-based ink was used. P of the ink obtained
H was 8.4.

The obtained water-based ink showed stable dispersion for a long period without aggregation. This ink is C.I. I.
Pigment Orange 13 showed a brighter orange color than the ink prepared in the same manner except that the same amount of Pigment Orange 13 was used. The weather resistance of this ink was good.

(Embodiment 2) The C.I. I. Pigment Orange 36 and C.I. I. Pigment Green 3
Using No. 6, an ink was similarly obtained.

The obtained water-based ink showed stable dispersion for a long period without aggregation. This ink is C.I. I.
Pigment Green 7 exhibited a lighter green color than the ink prepared in the same manner except that the same amount of Pigment Green 7 was used. The weather resistance of this ink was good.

(Embodiment 3) The C.I. I. Pigment Orange 36 and C.I. I. Pigment Blue 1
5: 4 and 15 parts of C.I. I. Pigment Green 36-5
Ink was obtained in the same manner using the above-mentioned parts.

The obtained water-based ink showed stable dispersion for a long period without aggregation. This ink is C.I. I.
Pigment Blue 15: 4 and C.I. I. Compared with the case of preparing the ink using Pigment Green 7, a bright cyan color was exhibited with a smaller amount of the green pigment used. The weather resistance of this ink was good.

(Example 4) C.I. I. Pigment Orange 36 and a styrene-acrylic acid-methacrylic acid resin (styrene / acrylic acid / methacrylic acid = 77/10).
/ 13; molecular weight 50,000, acid value 160, glass transition temperature 10
(7 ° C.) 20 parts of the two-roll kneaded material is added to a mixed solution of 210 parts of water, 35 parts of glycerin, 8 parts of triethanolamine, 90 parts of methyl ethyl ketone and 40 parts of isopropyl alcohol, and stirred at room temperature for 3 hours to suspend the colorant. A suspension was obtained.
C. of Example 1. I. Pigment Orange 36 and C.I. I. A blue colored suspension using CI Pigment Blue 15: 4 was obtained. Similarly, the C.I. I. A green colored suspension using Pigment Green 36 was obtained. An ink was similarly obtained using 15 parts of the blue colored suspension and 5 parts of the green colored suspension.

The obtained aqueous ink showed stable dispersion for a long period without aggregation. This ink is C.I. I.
Pigment Blue 15: 4 and C.I. I. Pigment Green 7 compared to preparing ink in the same way,
Vivid cyan was exhibited with less green pigment used. The weather resistance of this ink was good.

(Embodiment 5) The C.I. I. Pigment Orange 36 and C.I. I. Pigment Red 12
Magenta ink was obtained in the same manner using No. 2. Similarly, C.I.
I. Pigment Yellow 151 was similarly used to obtain a yellow ink. Similarly, a black ink was obtained using carbon black. These inks and Examples 1 to
Printing was performed using a piezo-type color printer having a six-color head by combining the inks of a total of six colors obtained in 3 above.

These inks show stable jetting without clogging, and the printed matter obtained is free of bleeding, and can be printed not only in a single color but also in full color printing as compared with the conventional combination of four colors of cyan, magenta, yellow and black. And showed extremely high color development.

The obtained printed matter was subjected to 150
When irradiated for a period of time (corresponding to one year of sunlight exposure), the primary, secondary, tertiary and full-colored colors hardly faded as compared to before irradiation. 150 with xenon lamp
After time irradiation (for a total of 300 hours, equivalent to two years of sun exposure), slight fading was observed throughout, but the fading manner was balanced for each color, and no remarkable color change was observed.

Comparative Example 4 C.I. I. Pigment Orange 36 and C.I. I. Pigment Orange 1
3 (pyrazolone), C.I. I. Pigment Green 36
In place of C. I. Pigment Green 7 (polychlorinated phthalocyanine) was used to obtain orange and green inks. Using these inks, a total of six inks were combined in the same manner as in Example 4, and printing was performed using a piezo-type color printer having a six-color head.

These inks showed stable jetting without clogging, and the obtained printed matter did not have bleeding. However, not only monochromatic printing but also full-color printing and a color obtained with a slightly duller color tone than that of Example 4 were obtained. The balance was not enough.

The obtained printed matter was subjected to 150
Irradiation for a period of time (corresponding to one year of sun exposure) showed a slight fading compared to before irradiation.

[0114]

The ink composition of the present invention is a recording aqueous ink composition containing a specific cyan pigment, orange pigment or green pigment coated with a resin as a coloring agent. The color image forming method of the present invention using these ink compositions is excellent in color tone and weather resistance (light resistance), enables stable ink jet ejection characteristics without nozzle clogging, and provides print quality and weather resistance (light resistance). )
Enables excellent recording.

Continued on the front page (72) Inventor Ritsuko Doi 1089-307 Ageomura, Ageo-shi, Saitama F-term (reference) 2C056 EA11 EE18 FB01 FB03 FC01 FC02 2H086 BA04 BA55 BA59 BA62 4J037 CC13 CC16 EE03 FF22 FF25 4J039 BC51 BC60 BE01 CA24

Claims (17)

[Claims] 1. An aqueous ink composition for recording comprising an orange pigment coated with a resin as a coloring agent, wherein the pigment is an imidazolone pigment. 2. An aqueous ink composition for recording which uses a green pigment coated with a resin as a coloring agent, wherein the pigment is a phthalocyanine pigment at least partially brominated. 3. A recording aqueous ink comprising a cyan pigment coated with a resin as a colorant, wherein the pigment is a mixture of a phthalocyanine pigment not halogenated and a phthalocyanine pigment at least partially brominated. Composition. 4. A cyan recording aqueous ink comprising a resin-coated pigment as a colorant, wherein at least a part of the resin-coated non-halogenated phthalocyanine pigment and the resin are brominated. An ink composition which is a mixture of a phthalocyanine pigment. 5. An imidazolone pigment comprising C.I. I. The ink composition according to claim 1, which is CI Pigment Orange 36. 6. A phthalocyanine pigment which is at least partially brominated is C.I. I. The ink composition according to claim 2, which is Pigment Green 36. 7. A non-halogenated phthalocyanine pigment comprising at least C.I. I. Pigment Blue 15: 3 or 15: 4, and at least partially brominated phthalocyanine pigment is C.I. I. 5. The ink composition according to claim 3, which is Pigment Green 36. 8. The method according to claim 3, wherein the cyan pigment coated with the resin comprises secondary particles in which a non-halogenated phthalocyanine pigment and at least a part of the phthalocyanine pigment are brominated. The ink composition as described in the above. 9. The resin is a copolymer essentially comprising a styrene monomer having a monomer ratio of 65 to 85 mol%, an acrylic acid manomer of 5 to 15 mol%, and a methacrylic acid monomer of 10 to 20 mol%. Claim 1 characterized by the above-mentioned.
9. The ink composition according to any one of 8. 10. A recording aqueous ink containing a pigment coated with a resin as a colorant, wherein the pigment is selected from the cyan ink according to any one of claims 3 or 4, or 7 or 8 or 9, and a quinacridone pigment. A color image forming method comprising forming an image using at least three colors of magenta ink and yellow ink composed of a benzimidazolone pigment. 11. A recording aqueous ink comprising a pigment coated with a resin as a colorant, a cyan ink containing a phthalocyanine pigment whose pigment is not halogenated as an essential component, a magenta ink containing a quinacridone pigment, 10. An ink of at least three colors of a yellow ink comprising a benzimidazolone pigment, an orange ink of any one of claims 1 to 5, and 9;
Or a method for forming an image using the green ink described in any one of 6 and 9 above. 12. A recording aqueous ink comprising a pigment coated with a resin as a colorant, wherein the aqueous ink is a recording ink.
Or a cyan ink according to any one of claims 8 or 9; a magenta ink comprising a quinacridone pigment; and at least three inks comprising a yellow ink comprising a benzimidazolone pigment; 10. A color image forming method, wherein an image is formed using the orange ink according to any one of claims 1 to 6 and the green ink according to any one of claims 2 to 6. 13. The color image forming method according to claim 10, wherein image formation is performed using a combination of at least four colors of ink obtained by combining black ink using carbon black as a coloring agent. 14. The color image forming method according to claim 11, wherein an image is formed using a combination of at least six colors of ink in combination with a black ink using carbon black as a coloring agent. 15. The quinacridone pigment is C.I. I. Pigment Red 122.
5. The color image forming method according to any one of the above items 4. 16. A benzimidazolone pigment comprising C.I. I. 16. The color image forming method according to claim 10, wherein the color image is CI Pigment Yellow 151. 17. The color image forming method according to claim 10, wherein the image is formed using an ink jet recording method.