JPH09255906A - Ink composition excellent in reproduction if black and ink jet recording method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink compsn. which is excellent in the reproduction of black and can yield images having both high quality and high waterproofness by incorporating a second group of dyes into a first group of dyes represented by specified formulae. SOLUTION: This ink compsn. comprises a first group of dyes and a second group of dyes. The first group of dyes comprise a dye represented by formula I [wherein R<1> represents -PO(OM)2 - or -COOM; X and Y represent each a 1-4C alkoxy; and M represents H or a cation of an alkali metal, ammonia, or an org. amine] with R<1> representing PO(OM)2 located at the m-position relative to the azo group and a dye with R<1> representing COOM located at the m- position relative to the azo group and the second group of dyes comprise a dye represented by formula II and/or formula III [wherein R<21> and R<22> represent each H or -C2 H4 OH; Z<1> to Z<4> represent each a group of formula IV or V (wherein R<41> and R<51> represent each H, a 1-4C alkyl, or a 1-4C alkoxy; A represents -SO3 M or -COOM; M is as defined above; and n is 1 or 2)].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition having excellent black color reproducibility and an inkjet recording method using the same.

[0002] The ink used in the background art ink jet recording system, the various dyes in water or an organic solvent, or it which is dissolved in a mixture of these is common in a variety of properties, as fountain pens or ballpoint More stringent conditions are required as compared with various writing inks.

Further recent trends include high-quality images (clear images with high optical density and no bleed), high speed, and water resistance of printed matter in the ink jet recording system.
There is a strong demand for light resistance.

In order to realize high speed printing,
Rapid fixing of ink is required. Therefore, attempts have been made to improve the penetrability of ink into a recording medium. For example, in JP-A-4-183761, US Pat. No. 5,156,675, US Pat. No. 5,183,502 and the like, addition of diethylene glycol monobutyl ether and addition of both glycol ethers and nonionic acetylene glycol-based surfactants are described. What to do is disclosed. In addition, in this specification, an ink having a high permeability to a recording medium may be referred to as a permeation ink.

However, these penetrating inks are used for plain paper (office, school,
Copy paper, report paper, bond paper, used at home
It is difficult to obtain a clear image with high optical density, because the color development tends to deteriorate due to the ink penetrating into the paper (such as letter paper, postcards, slips, etc.). was there. If the dye concentration is increased in order to increase the optical density, there is a possibility that reliability problems such as clogging may occur. Therefore, the dye used in the penetrating ink is required to have extremely high solubility.

As a highly soluble dye, C.I. I. Food Black 2 (Japanese Patent Laid-Open No. 59-93766, etc.),
Many other direct and acid dyes have been widely known,
In fact, it has been widely used as an ink for inkjet recording. However, high solubility in water means that it is easily soluble in water, resulting in poor water resistance of printing.

Therefore, in order to obtain water resistance, Japanese Patent Application Laid-Open No. 5-1
No. 40495 discloses pyrrolidone (2-pyrrolidone, N
An ink composition containing-(2-hydroxyethyl) -2-pyrrolidone or a mixture thereof has been proposed. Although this ink composition is certainly excellent in water resistance and ink droplet ejection stability, it has not yet fully satisfied all the properties required for ink.

In order to improve the water resistance of printed matter, a black dye having water resistance and an ink containing the dye have been proposed as a coloring material. For example, US Pat.
3189 and U.S. Pat. No. 5,203,912 disclose dyes which are characterized by being readily soluble in bases while not soluble in neutral water. Then, an ink has been proposed which can obtain a printed matter having excellent water resistance.

In Japanese Patent Publication No. 5-80956, a diazo dye having a phosphoric acid group is used, and in Japanese Patent Laid-Open Nos. 3-91577 and 5-262998, a disazo dye having a carboxylic acid group is used. Ink proposals have been made.

However, since the dye having water resistance tends to be difficult to dissolve in the medium of the ink, there is a problem that clogging is likely to occur at the fine ejection port of the ink jet head. Further, there is a problem that a dye having water resistance is not suitable for use in a penetrating ink.

On the other hand, the ink composition is required to reproduce a true black color. The hue of some dyes tends to be bluish, which is somewhat different from the original black (for example, black called jet black such as black and lacquer). Studies have also been conducted to combine complementary dyes to improve the hue. However, by combining the complementary color dyes, the original water resistance of the ink may be impaired, or the reliability such as clogging may be adversely affected.

Further, various proposals have been made on ink compositions using existing dyes and novel structural dyes, which are excellent in water resistance. However, sufficient water resistance is satisfied, black reproducibility is excellent, and high quality images are obtained. It can be said that there is still a demand for an ink that realizes.

[0013]

SUMMARY OF THE INVENTION The present inventors have now found that high-quality images and water-resistant images can be made compatible by using specific dyes in combination. More specifically, due to the combination of specific dyes, it has excellent black reproducibility and high-quality images even on plain paper (high optical density,
It was found that an ink composition that can realize a clear image without bleeding, and that can quickly fix the ink, and provide water resistance and light resistance of the printed matter can be realized.

Therefore, an object of the present invention is to provide an ink composition capable of achieving both high quality images and water resistant images.

Further, the present invention is excellent in black reproducibility and can realize high-quality images (clear images with high optical density and no bleed) even on plain paper, prompt ink fixing, and water resistance of printed matter. The object is to provide an ink composition that imparts light resistance.

The ink composition of the first aspect of the present invention is an ink composition comprising at least a first dye group and a second dye group, wherein the first dye group is A dye represented by the formula (I), wherein R ¹ represents PO (OM) ₂ in the m-position to the azo group, and R ¹ represents COOM in the m-position to the azo group. Comprising a dye that represents,
The second dye group comprises a dye represented by the following formula (II) and / or a dye represented by the following formula (III).

[0017]

Embedded image [Wherein, R ¹ represents —PO (OM) ₂ or —COOM, X and Y each independently represent C _1-4 alkoxy, and M represents a hydrogen atom, an alkali metal, ammonia, and an organic amine. Represents a cation of a group selected from the group consisting of: ]

[0018]

[Chemical 6] [In the formula, R ²¹ and R ²² each independently represent a hydrogen atom or —C ₂ H ₄ OH, and Z ¹ , Z ² , Z ³ , and Z ⁴ are each independently the following formula (IV) or Representing a group of formula (V):

[0019]

Embedded image [Wherein R ⁴¹ and R ⁵¹ are each independently a hydrogen atom,
C _1-4 alkyl or C _1-4 alkoxy, A represents —SO ₃ M or —COOM, M has the same meaning as defined above, and n is 1 or 2. )] The ink composition of the second aspect of the present invention is a dye represented by the above formula (I), wherein R ¹ is PO (OM) ₂ or COOM in the m-position to the azo group. And a dye that represents
An ink composition comprising a dye represented by the following formula (VI).

[0020]

Embedded image [In the formula, M has the same meaning as defined above, m represents 1 or 2, and n represents 0 or 1. Further, the ink composition of the third aspect of the present invention is a dye group A
And a dye group B, wherein the dye group A is a dye represented by the formula (I) defined above and a formula (VI) defined above. An ink composition, wherein dye group B is a second dye group as defined above.

[0021]

DETAILED DESCRIPTION OF THE INVENTION The ink composition according to the present invention is used in a recording system using the ink composition. The recording method using the ink composition includes, for example, an inkjet recording method, a recording method using a writing instrument such as a pen, and various other printing methods such as a recorder and a pen plotter. In particular, the ink composition according to the present invention is preferably used for an ink jet recording method. As the ink jet recording method, a method of ejecting droplets by utilizing vibration of a piezoelectric element, a method of utilizing thermal energy, and other known or future known ink jet recording methods can be used. Further, the ink composition according to the present invention may be dried and fixed after printing by a suitable heat fixing means (for example, hot air, heating roll / plate, infrared ray, etc.).

Ink Composition of First Aspect The ink composition according to the first aspect of the present invention comprises a first dye group and a second dye group.

By combining these two dye groups, a good black color can be reproduced, and a water-resistant printed material can be realized. Furthermore, copy paper, report paper, used in offices, schools, and homes called plain paper,
Good black color can be reproduced on bond paper, letter paper, postcards, slips, etc., and it is possible to realize water-resistant printed matter.

The abundance ratio of the first dye group and the second dye group in the ink composition may be appropriately determined within the range in which the above advantages can be obtained. For example, the first dye group and the second dye group The weight ratio of the second dye group in the ink composition is 1: 0.1 to 1: 1.
It is preferably in the range of 0.5.

The amount of all dyes added to the ink composition may be appropriately determined within the range in which the above-mentioned advantages are obtained, but is preferably about 1 to 25% by weight, more preferably about 2 to 10% by weight. Is.

The first dye group is a dye represented by the above formula (I), wherein R ¹ is PO (O) in the m-position to the azo group.
M) ₂ dye and R ¹ is C at the m-position to the azo group
And a dye representing OOM.

In the formula (I), C represented by X and Y
_1-4 Alkoxy is preferably a methoxy group, an ethoxy group or a butoxy group.

In formula (I), examples of the alkali metal represented by M include lithium, sodium and potassium. Examples of the organic amine represented by M include mono-, di-, or tri-lower alkyl-substituted (preferably C _1-4 alkyl-substituted) amine, allylamine, morpholine, piperidine, and the like. Examples thereof include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, diisopropylamine, butylamine, isobutylamine, sec-butylamine, tert-butylamine and dibutylamine.

According to a preferred embodiment of the present invention, as the first dye group, PO in which R ¹ is m-position in the formula (I) is used.
A dye representing (OM) ₂ and R ¹ in the formula (I) is m-
And a dye representing COOM at a weight ratio of 1: 0.6
It is preferable to comprise in the range of about 1: 1.5. By using such a first dye group, an ink composition excellent in storage stability can be realized. More specifically, an ink composition that does not generate precipitates during storage can be obtained.

The dye in which R ¹ represents PO (OM) ₂ in the m-position with respect to the azo group in the formula (I) constituting the first dye group is disclosed in JP-B-5-80956. It is a disazo dye having a phosphoric acid group included in the dye group. Since this dye has a phosphate group in the dye structure,
It has good dyeing properties for cellulose fibers such as paper and excellent water resistance. Moreover, since it has a water-soluble acid group such as a sulfonic acid group at the same time, it has excellent solubility in an aqueous liquid medium. Solubility in water depends on the pH of the water solvent,
It exhibits good solubility at pH 7.5 to 11, preferably pH 8.5 to 10, and becomes poorly soluble at acidic pH. This dye can be synthesized, for example, as follows. That is, m-aminobenzenephosphonic acid is diazotized by a conventional method and coupled with 2,5-diC _1-4 alkoxy-substituted aniline to produce a monoazo compound having an amino group. This can be obtained by isolating it, or subsequently diazotizing it by a conventional method, and coupling it with γ-acid (2-amino-8-naphthol-6-sulfonic acid).

Further, in the formula (I) which constitutes the first dye group, dyes in which R ¹ represents COOM at the m-position are disclosed in JP-A-5-58200.
It is a disazo dye having a carboxylic acid group, which is disclosed in JP-A-262998 or JP-A-5-125318. Since this dye has a carboxylic acid group in the dye structure, it has good water resistance. At the same time, since it has a water-soluble acid group such as a sulfonic acid group, it dissolves in an aqueous liquid medium in the form of an alkali metal salt or ammonium salt. pH
If it is 6 or less, it becomes insoluble. It has good solubility at pH 8.0 to 10. This dye can be synthesized, for example, as follows. That is, m-aminobenzenecarboxylic acid is diazotized by a conventional method and coupled with 2,5-diC _1-4 alkoxy-substituted aniline to produce a monoazo compound having an amino group. This can be obtained by isolating it, or subsequently diazotizing it by a conventional method, and coupling it with γ-acid (2-amino-8-naphthol-6-sulfonic acid).

In the formula (I) preferably used in the present invention, R ¹ is PO (O) in the m-position to the azo group.
Specific examples of the dye represented by M) ₂ and the dye represented by formula (I) in which R ¹ represents m-position COOM include the following.

[0033]

Embedded image

[0034]

Embedded image

[0035]

Embedded image

[0036]

Embedded image

[0037]

Embedded image

[0038]

Embedded image The two dyes constituting the first dye group may be separately synthesized and mixed, or may be simultaneously synthesized as a mixture of the two dyes. Examples of such a method of simultaneous synthesis include the methods described in the following schemes.

[0039]

Embedded image In step (i), a mixed amine of m-aminobenzenephosphonic acid and m-aminobenzenecarboxylic acid is simultaneously diazotized, for example, at a temperature of 0 to 5 ° C. Next, in the step (ii), a coupling reaction is carried out with the 2,5-dialkoxy-substituted aniline, for example, at a temperature of 0 to 5 ° C and a pH of 0.5 to 3.5. In step (iii), the obtained monoazo compound is diazotized, for example, at a temperature of 25 to 35 ° C, and subsequently at a temperature of 5 to 15 ° C and a pH of 9 to 10,
Gamma acid (2-amino-8-naphthol-6-sulfonic acid)
And the coupling reaction.

The second dye group used in the first embodiment of the present invention comprises a dye represented by the formula (II) and / or a dye represented by the formula (III).

Dyes belonging to these second dye groups are known, for example, JP-A-4-233975, color index (THE SOCIETY OF DYERS AND COLOURISTS).
It is described in.

Specific examples of the dyes included in the second dye group which are preferably used in the present invention are as follows.

[0043]

Embedded image According to a preferred embodiment of the present invention, the combination in which M in formula (I) represents the cation of a volatile compound and M in formula (II) and / or formula (III) is an alkali metal cation. It is preferable from the viewpoints of water resistance of printing and prevention of nozzle clogging. Here, the volatile compound means ammonium, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, diisopropylamine, butylamine, isobutylamine, sec-butylamine, tert- Butylamine, dibutylamine, allylamine, morpholine, piperidine and mixtures thereof.

The ink composition according to the first aspect of the present invention basically comprises the above dye group, water, and an organic solvent.

According to a preferred embodiment of the present invention, a nitrogen-containing cyclic compound and a polyhydric alcohol are preferably used as the organic solvent in combination with the above dye group.

The addition of the nitrogen-containing cyclic compound stabilizes the dissolution of the dye, prevents the nozzle from clogging, and enables stable printing. Further, it is possible to obtain the advantages of assisting the color development of the dye and improving the water resistance of printing. The amount added is preferably about 1 to 30% by weight, more preferably 3 to 20% by weight. Specific examples of the nitrogen-containing cyclic compound include 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidone, N-methyl-2-pyrrolidone,
ε-caprolactam, a mixture thereof, and the like.

Further, the addition of the polyhydric alcohol has an advantage that the clogging of the nozzle can be prevented more effectively. The amount added is preferably about 1 to 30% by weight, more preferably 3 to 20% by weight. Specific examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, 1,3-propanediol, 1,5-pentanediol, 1,2,6-hexanetriol, glycerin, and Mention may be made of mixtures thereof.

According to a preferred aspect of the present invention, the ink composition of the first aspect of the present invention comprises a nonionic acetylene glycol-based surfactant. This addition has the advantages that the ink can be rapidly fixed (permeability) and the roundness of one dot can be maintained.

Specific examples of the nonionic acetylene glycol-based surfactant used in the present invention include Surfynol 465, Surfynol 104, Olfine STG (trade name, manufactured by Nisshin Chemical Co., Ltd.), and the like. Olfine STG is effective. The amount added is preferably about 0.05 to 3% by weight, more preferably 0.5 to 2% by weight.

According to a preferred embodiment of the present invention, the ink composition of the first embodiment of the present invention comprises glycol ethers. By this addition, the permeability of the ink is further increased, and the bleeding at the boundary between the adjacent color inks when color printing is performed can be reduced, and a very clear image can be obtained.

The glycol ethers used in the present invention include, for example, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether,
Examples thereof include triethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether and triethylene glycol monobutyl ether. The amount added is preferably about 3 to 30% by weight, more preferably 5 to 15% by weight.

According to a preferred embodiment of the present invention, the pH of the ink composition is preferably adjusted by the addition of tri (hydroxyalkyl) amine. As a pH adjusting method, a method using an inorganic base such as KOH or NaOH,
Alternatively, a method using an organic base such as amines can be considered. The inorganic base may cause a sharp rise in pH from a certain amount of addition, which may be difficult to control. In addition, since the inorganic base is a solid, the inorganic base itself is deposited in the ink composition to cause nozzle clogging. It may be a cause. Also,
The organic base may react with a dye or the like because the nitrogen atom is positively charged. Care must be taken so that the above-mentioned problems do not occur regardless of whether these inorganic bases or organic bases are used. On the other hand, tri (hydroxyalkyl) amine is preferably used because it causes less of the above problems. The addition amount thereof may be appropriately determined in consideration of the required pH and other characteristics of the ink composition, but is preferably about 0.1 to 2% by weight, more preferably 0.3 to 1% by weight. It is a degree.

Further, according to a preferred embodiment of the present invention, the above-mentioned tri (hydroxyalkyl) amine is further contained, and at least one hydroxide of a metal element selected from the group consisting of the element period Ia is further included. More preferable. This hydroxide belongs to the above-mentioned inorganic bases, but when used together with tri (hydroxyalkyl) amine, the clogging recovery property is further improved. Furthermore, only the above-mentioned inorganic base is added.
Compared with the case where H adjustment is performed, the advantage that less precipitates are generated and the pH does not change is obtained. As the metal hydroxide, LiOH, NaOH, KOH and the like are preferable because they have high solubility in water. The addition amount may be appropriately determined within a range in which the properties of the ink, particularly the clogging recovery property are improved, but it is preferably about 0.01 to 1% by weight.

Further, a dye may be further added to the ink composition of the first aspect according to the present invention within the range where the effects of water resistance and black reproducibility are not impaired. If necessary, lower alcohols, water-soluble polymers such as sodium alginate, water-soluble resins, fluorochemical surfactants, fungicides, rust preventives and the like may be added.

When the ink composition according to the present invention is used in an ink jet recording method, good responsiveness, ejection stability,
The viscosity of the ink composition is preferably 30 mPa · s or less at an operating temperature of 0 to 50 ° C., and more preferably 1.2 to 20 mPa ·, in order to realize appropriate dot spread and good roundness. The surface tension of the ink composition is preferably about 20 to 35 mN / m at an operating temperature of 0 to 50 ° C.

The ink composition according to the first aspect of the present invention can be manufactured by a conventional method. For example, the respective components are sufficiently mixed and dissolved, filtered under pressure with a membrane filter having a pore size of about 0.8 μm, and then deaerated using a vacuum pump to prepare an ink.

Ink Composition According to Second Aspect The ink composition according to the second aspect of the present invention is a dye represented by the above formula (I), wherein R ¹ is m-position to the azo group. A dye representing PO (OM) ₂ or COOM,
And a dye represented by the above formula (VI).

By combining these two dye groups, a good black color can be reproduced, and a printed product having water resistance can be realized. Furthermore, copy paper, report paper, used in offices, schools, and homes called plain paper,
Good black color can be reproduced on bond paper, letter paper, postcards, slips, etc., and it is possible to realize water-resistant printed matter.

The abundance ratio of the dye represented by the formula (I) and the dye represented by the formula (VI) in the ink composition may be appropriately determined within the range where the above advantages can be obtained. The weight ratio of the dye represented by I) to the dye represented by the formula (VI) is 4:
The content is preferably in the range of 1 to 1:10, more preferably in the range of 3: 1 to 1: 5.

The amount of the dye added to the ink composition may be appropriately determined within the range in which the above-mentioned advantages are obtained, but is preferably about 1 to 20% by weight, more preferably 2.5 to 10% by weight. It is a degree.

The dye represented by formula (I) used in the ink composition according to the second aspect of the present invention may have the same meaning as described in the first aspect of the present invention. The preferred specific examples thereof may be the same, and therefore preferred specific examples include the above (I-1) to (I-2).
The dye of 4) is mentioned. In the present embodiment, the dye represented by the formula (I) means that R ¹ is m- with respect to the azo group.
It may be either a dye representing PO (OM) ₂ at the position or a dye in which R ¹ represents COOM at the m-position with respect to the azo group.

According to a preferred embodiment of the present invention, the formula (I)
It is preferred that M therein is a volatile alkali salt such as ammonium, substituted ammonium, morpholinium, or piperidinium. This is because the water resistance of the printed matter is further improved by utilizing these. Examples of amines used to form such salts include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, diisopropylamine, butylamine, isobutylamine, sec- Butylamine, tert-butylamine, dibutylamine, allylamine, morpholine, piperidine and mixtures thereof. However, the dye of formula (I) does not need to be completely ammonium salt, substituted ammonium salt, morpholinium salt, piperidinium salt, and may be a mixture with an alkali metal salt. In that case, the ratio of the alkali metal salt to the entire dye is preferably 50% or less.

The dye represented by the above formula (VI) used in the second embodiment of the present invention is as described in US Pat.
Known dyes described in US Pat. No. 5,203,912.

Preferred specific examples of the dye represented by the formula (VI) include the following.

[0065]

Embedded image

[0066]

Embedded image As described above, the dye represented by the formula (VI) is the dye described in US Pat. No. 4,963,189 and US Pat. No. 5,203,912.
Since it is described in the specification, it can be manufactured by referring to those descriptions. In addition, Japanese Unexamined Patent Application Publication No.
No. 140270, Color Index Third Edition (Colou
r Index, Third Edition, The societyof Dyers and Co
It can also be produced by the method described in lourists).

The dyes represented by the above formulas (I) and (VI) are disclosed in JP-B-5-80956 or JP-A-5-9556.
-262998, JP-A-5-125318, US Pat. No. 4,963,189, US Pat. No. 5
As is known in the specification such as the 203,912 specification, the added ink composition is required to be basic for dissolution. Therefore, also in the ink composition according to the present invention,
The pH is preferably adjusted to be basic. According to a preferred embodiment of the present invention, the ink composition has a pH of 8.
It is preferably in the range of 5 to 11, and more preferably in the range of 8.5 to 10.

The ink composition according to this embodiment basically comprises the above dye group, water, and an organic solvent.

According to a preferred embodiment of the present invention, as an effective additive for obtaining quick fixing (permeability) of ink and preventing bleeding in color printing,
The addition of glycol ethers is preferred. Specific examples of glycol ethers include ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol. Monobutyl ether,
Examples include triethylene glycol monobutyl ether. The addition amount thereof may be appropriately determined within a range in which the effect of the ink permeability and the ability to prevent bleeding can be obtained. The dye represented by the formula (I) and the dye represented by the formula (IV) are glycols. Since it is hardly soluble or insoluble in ethers, excessive addition thereof may cause nozzle clogging, so that it is preferably about 3 to 30% by weight, more preferably about 5 to 15% by weight.

Also in the ink composition of this embodiment, it is preferable to add a nonionic acetylene glycol-based surfactant for the same reason as in the ink composition of the first embodiment.
Specific examples thereof include those described above in the first aspect. The addition amount thereof may also be appropriately determined, but in the present embodiment, it is preferably about 0.05 to 5% by weight, more preferably about 0.1 to 2% by weight.

Also in this embodiment, the pH of the ink composition is the same as in the case of the ink composition according to the first embodiment.
Is preferably adjusted by the addition of tri (hydroxyalkyl) amine. The same may be applied to the added amount.

Further, also in this embodiment, for the same reason as in the case of the ink composition according to the first embodiment, the hydroxylation of the metal element selected from the group consisting of the group Ia of the elemental period together with tri (hydroxyalkyl) amine is performed. At least one
More preferably, it comprises one. The same may be applied to the added amount.

Also, in the ink composition of the second aspect according to the present invention, like the ink composition of the first aspect,
A dye may be further added within a range that does not impair the effects of water resistance and black color reproducibility. If necessary, lower alcohols, water-soluble polymers such as sodium alginate, water-soluble resins, fluorochemical surfactants, fungicides, rust preventives and the like may be added.

When the ink composition according to the present invention is used in an ink jet recording method, it is preferable that the ink composition has the same viscosity and surface tension as those of the ink composition according to the first aspect of the present invention.

The ink composition of this embodiment can also be produced by the same method as the above-mentioned ink composition of the first embodiment of the present invention.

Ink Composition According to Third Aspect The ink composition according to the third aspect of the present invention comprises a dye group A.
And a dye group B.

By combining these two dye groups, it is possible to reproduce a good black color and realize a printed matter having water resistance. Furthermore, copy paper, report paper, used in offices, schools, and homes called plain paper,
Good black color can be reproduced on bond paper, letter paper, postcards, slips, etc., and it is possible to realize water-resistant printed matter.

The abundance ratio of the dye group A and the dye group B in the ink composition may be appropriately determined within the range where the above advantages are obtained, but the weight ratio is 1: 0.1 to 1: 0.5. It is preferably contained in the range.

The amount of the dye added to the ink composition may be appropriately determined within the range in which the above-mentioned advantages are obtained, but is preferably about 1 to 25% by weight, more preferably about 3 to 15% by weight. is there.

In this embodiment, the dye group A is a dye of the above formula (I)
And a dye represented by the above formula (VI).

Here, the dye represented by the above formula (I) is
It may have the same meaning as described in the first aspect of the present invention. In the present embodiment, the dye represented by the formula (I) is not particularly specified in the substitution position of R ¹ , but a dye that represents PO (OM) ₂ or COOM at the m-position to the azo group is preferable. Furthermore, the preferred specific examples thereof may be the same as those in the first aspect, and therefore preferred specific examples include the dyes (I-1) to (I-24) described above.

According to a preferred embodiment of the present invention, the ink composition of the present embodiment comprises a dye represented by the formula (I) and a compound represented by the formula (VII:
) And a dye represented by the formula (4) in a weight ratio of 4: 1 to 1:10, and more preferably 3: 1 to 1:10.
1: 5. When the weight ratio is within the above range, the solubility of the dye group A in the aqueous solvent is improved and the dissolution stability is also improved, which is preferable.

The addition amount of the dye group A to the ink composition may be appropriately determined, but is preferably about 1 to 20% by weight, more preferably about 2.5 to 10% by weight.

In this embodiment, the dye group B has the same meaning as the second dye group described in the first embodiment of the present invention. That is, it comprises a dye represented by the formula (II) and / or a dye represented by the formula (III). further,
Its preferred embodiment may also be the same as that of the first aspect, and therefore, as a preferred embodiment, the above (II-
1), (II-2), (III-1), and (III-2)
Dyes.

Also in this embodiment, as in the ink composition according to the first embodiment of the present invention, M in the formula (I) represents a cation of a volatile compound, and the formula (II) and / or
Alternatively, a combination in which M in the formula (III) is an alkali metal cation is preferable from the viewpoint of water resistance of printing and prevention of nozzle clogging. As the volatile compound, the same compounds as in the case of the first aspect can be mentioned.

Further, the ink composition according to this embodiment basically comprises the above dye group, water, and an organic solvent.

Also in this embodiment, for the same reason as in the ink composition according to the first embodiment of the present invention, a nitrogen-containing cyclic compound and a polyhydric alcohol are used as the organic solvent in combination with the above dye group. preferable. Specific examples and addition amounts thereof may be the same as those of the ink composition according to the first aspect.

Also in this embodiment, for the same reason as in the ink composition according to the first embodiment, it is preferable that the nonionic acetylene glycol surfactant is contained.
The specific example and the addition amount thereof may be the same as those of the ink composition according to the first aspect. Also in this aspect,
For the same reason as that of the ink composition according to the first aspect, it is preferable to include glycol ethers. Specific examples and addition amounts thereof may be the same as those of the ink composition according to the first aspect.

Also in this embodiment, for the same reason as in the case of the ink composition according to the first embodiment, the pH of the ink composition is
Is preferably adjusted by the addition of tri (hydroxyalkyl) amine. The same may be applied to the added amount.

Further, also in this embodiment, for the same reason as in the case of the ink composition according to the first embodiment, the hydroxylation of the metal element selected from the group consisting of the group Ia of the elemental period together with tri (hydroxyalkyl) amine is performed. At least one
More preferably, it comprises one. The same may be applied to the added amount.

Further, also in the ink composition of the third aspect according to the present invention, like the ink composition of the first aspect,
A dye may be further added within a range that does not impair the effects of water resistance and black color reproducibility. If necessary, lower alcohols, water-soluble polymers such as sodium alginate, water-soluble resins, fluorochemical surfactants, fungicides, rust preventives and the like may be added.

When the ink composition according to the present invention is used in an ink jet recording method, it is preferable that the ink composition has the same viscosity and surface tension as those of the ink composition according to the first aspect of the present invention.

The ink composition of this aspect can also be produced by the same method as that for the ink composition of the first aspect of the present invention.

[0094]

EXAMPLES The present invention will be described in detail with reference to the following Examples, but the present invention is not limited to these Examples.

In the following examples, the dye numbers correspond to the above specific dye numbers.

Example A Synthesis of dye (I-1) 34.62 g (0.20 ) of m-aminobenzenephosphonic acid
(mol) was suspended in 400 ml of water while stirring, and 35% hydrochloric acid (30.4 g, 0.29 mol) was added thereto, and the mixture was added at 0 ° C.
And cooled. To this solution, 40.0 g (0.2%) of 36% sodium nitrite aqueous solution was gradually added so that the temperature did not exceed 5 ° C.
1 mol) was appropriately applied, and the mixed amine was diazotized by stirring for 50 minutes. Then, thiourea was added to the obtained aqueous solution to remove excess nitrous acid, to obtain a diazo component-containing liquid. On the other hand, 3,5-diethoxyaniline 36.3 g
(0.22 mol) was dispersed in 500 ml of water, and 21.3 g (0.21 mol) of 35% hydrochloric acid was added and dissolved.
A liquid containing a coupling component was obtained. Here, the coupling component-containing liquid was cooled to 0 ° C., and the above diazo component-containing liquid was added dropwise thereto so that the temperature did not exceed 5 ° C. Then 3
Monoazo compound; m- (2,
5-Diethoxy-4-amino-phenylazo) benzenephosphonic acid was obtained.

The obtained monoazo compound mixture was mixed with water 900
Dispersed in ml, 45% sodium hydroxide aqueous solution 43.0
g (0.48 mol) was added and dissolved. 36 in this solution
% Aqueous sodium nitrite solution 38.5 g (0.20 mo
l) was added and the mixture was cooled to 25 ° C.
g (0.71 mol) was gradually added so as not to exceed 30 ° C., and the mixture of monoazo compounds was diazotized by stirring at 25 to 30 ° C. or lower for 3 hours. Then, sulfamic acid was added to the obtained aqueous solution to remove excess nitrous acid to obtain a diazo component liquid.

51.6 g (0.21 mol) of gamma acid was added to water 6
In addition to 00 ml, 45% sodium hydroxide aqueous solution 37.
The solution was dissolved in 0 g (0.42 mol) and cooled to 5 ° C. to prepare a coupler solution. A liquid containing the diazo component of the monoazo compound prepared above was added dropwise thereto so that the reaction temperature did not exceed 8 ° C. and the reaction pH was maintained at 8.5 or more by adding a 20% aqueous sodium hydroxide solution. Then, the mixture was stirred at 8 ° C for 3 hours. About 80 g of the disazo dye represented by the dye (I-1) was obtained by the salt / acid precipitation operation.

Synthesis of dye (I-9) 27.40 g (0.20 ) of m-aminobenzenecarboxylic acid
mol) was used, and the disazo dye represented by the dye (I-9) was prepared in the same manner as in the production of the dye (I-1).
g was obtained.

Preparation of Ink Compositions The ink compositions described in the following table were prepared. In particular,
All ingredients were mixed and stirred at 70 ° C. for 1 hour. Then, the mixture was naturally cooled while continuing stirring, and when the temperature reached 40 ° C. or lower, it was filtered under reduced pressure with a 0.8 μm membrane filter to obtain the desired ink.

In the table, the ink compositions used as examples are the ink compositions according to the first aspect of the present invention. The numerical values in the table represent% by weight, and the balance of the composition is water.

[0102]

[Table 1] In the table, the dyes (I-1) and (I-9) were added to the ink composition in the form of ammonium salt. Proxel XL-2 is a fungicide manufactured by Zeneca Corporation.

Printing Evaluation Test The following printing evaluation test is performed by the inkjet printer MJ.
A black ink cartridge for -700V2 / C (manufactured by Seiko Epson Corporation) was filled with the inks of the above-mentioned Example A and Comparative Ink Example A, and the following tests 1 to 6 were evaluated.

The following test papers were used for image quality evaluation.
(1) to (4) are so-called plain papers, and (5) is paper for exclusive use in an inkjet printer (coated paper).

(1) EPP paper (Epson Sales Co., Ltd.) (2) Xerox P (Fuji Xerox Co., Ltd.) (3) Xerox 4024 (Xerox Co.) (4) Riccopy 6200 (Ricoh Co., Ltd.) (5) ) EPSON Fine Paper (Epson Sales Co., Ltd.)

Test 1 : Black color reproducibility Graphic printing was carried out on the above-mentioned test paper, and the hue (spectral characteristics / L ^* a ^* b ^* ) of the solid part was measured, "Electrophotographic Society Test Chart No. 5" (1988). The color difference (ΔE) with the black sample shown in (Year) as the standard color was determined.

In the hue measurement, the spectral characteristics in the wavelength region of 350 to 750 nm were measured by using Macbeth spectrophotometer CE-7000 manufactured by Macbeth. Based on the measured spectral characteristics, the lightness (L ^* ) and chromaticity (a
^When the difference between ^* , b ^* ) is ΔL ^* , Δa ^* , Δb ^* ,
The color difference (ΔE) is calculated by the following formula.

ΔE = [(ΔL ^* ) ² + (Δa ^* ) ² +
(Δb ^* ) ² ] ^{1/2 From the} obtained ΔE value, black reproducibility was evaluated as follows.

⊚: ΔE ≦ 1 ○: 1 <ΔE <3 Δ: 3 ≦ ΔE <5 x: ΔE ≧ 5

Test 2 : 2-1 : Image Quality The above test paper was subjected to alphabetic printing and graphic printing, the visual density and the optical density (OD value) of the solid portion were measured, and evaluated according to the following criteria.

For the OD value measurement, Macbeth TR-927 manufactured by Macbeth Co. was used to measure the reflection density.

⊚: No bleeding and OD value of 1.30 or more ◯: Some bleeding is observed but does not affect the image, OD value is 1.25 or more Δ: Little bleeding, but OD value of 1.25 Less than x: OD value less than 1.20

2-2 : Bleed Inkjet Printer MJ-700V2 / C Color printing was carried out together with the mounted color ink, and the bleeding at the boundary between the black ink and the color ink was visually observed, and the result was evaluated according to the following criteria. .

⊚: No bleeding and clear ◯: Some bleeding, but clear Δ: Bleed is slightly conspicuous ×: Bleed is severe

Test 3 : Water resistance The above recording papers (1) and (2) were printed with letters. Water droplets were dropped on the printed sample and the state of the sample after natural drying was visually observed, and the result was evaluated according to the following criteria.

⊚: No change from the initial state ◯: Dye slightly melted out, but characters were clearly readable Δ: Bleeding was found, but characters were readable ×: Characters were bleeding and not readable

Test 4 : Recovery from clogging After the recording head of the printer was filled with ink, the recording head was left at 40 ° C. for one month while being displaced from the cap position. After that, when printing was started, the number of cleanings required until normal printing was possible was evaluated as follows.

⊚: 0 to 2 times ◯: 3 to 4 times △: 5 to 10 times ×: No recovery after 10 times

Test 5 : Drying property After a lapse of a certain time after printing, the printed part was rubbed with the edge of the same kind of paper as the recording medium, and the presence or absence of rubbing was observed, and the result was evaluated as follows.

⊚: Rubbing immediately after printing, no rubbing confirmed ◯: Rubbing 10 seconds after printing, no rubbing confirmed ×: Rubbing 10 seconds after printing, rubbing confirmed

Test 6 : Storage stability Fill the ink cartridge of the printer with ink, and
It was left at 30 ° C. and 70 ° C. for 2 weeks. Before and after leaving
The physical properties of the ink, the change in color tone, and the presence or absence of foreign matter / precipitates were observed, and the results were evaluated as follows.

◯: No change in physical property / color tone, no generation of foreign matter / precipitate ×: Change in physical property / color tone, or generation of foreign matter / precipitate Evaluation results of tests 1 to 6 above Was as shown in the following table.

[0123]

[Table 2]

Example B The ink compositions listed in the table below were prepared in the same manner as Example A.

[0125]

[Table 3] In the table, the dyes (I-1) and (I-9) were added to the ink composition in the form of ammonium salt.

Print Evaluation Test For the ink composition of Example B above, Tests 1 to 6 above
A printing test similar to the above was performed. The results are shown in the table below.

[0127]

[Table 4]

Example C The ink compositions described in the following table were prepared in the same manner as Example A.

[0129]

[Table 5]

Print Evaluation Test For the ink composition of Example C above, the above tests 1 to 6 were conducted.
A printing test similar to the above was performed. The results are shown in the table below. The results are shown in the table below.

[0131]

[Table 6]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Owata 3-5 Yamato 3-chome, Suwa, Nagano Prefecture

Claims (22)

[Claims] 1. An ink composition comprising at least a first dye group and a second dye group, wherein the first dye group is a dye represented by the following formula (I): , it comprises a dye wherein R ¹ represents m- position of PO (OM) ₂ to the azo group, and a dye wherein R ¹ represents m- position of COOM to the azo group, the second dye group Is an ink composition comprising a dye represented by the following formula (II) and / or a dye represented by the following formula (III). Embedded image [Wherein, R ¹ represents —PO (OM) ₂ or —COOM, X and Y independently represent C _1-4 alkoxy, and M 1
Represents a cation of a group selected from the group consisting of hydrogen atom, alkali metal, ammonia, and organic amines. ] [Chemical 2] [Wherein R ²¹ and R ²² are each independently a hydrogen atom or —C
₂ H ₄ OH, Z ¹ , Z ² , Z ³ , and Z ⁴ are
Each independently represents a group represented by the following formula (IV) or formula (V): [In the formula, R ⁴¹ and R ⁵¹ each independently represent a hydrogen atom, C _1-4 alkyl, or C _1-4 alkoxy, and A is —SO ₃
Represents M or -COOM, M has the same meaning as defined above, and n is 1 or 2. )] 2. As a first dye group, R in the formula (I) is used.
¹ and the dye representing the the m- position of PO (OM) _2, formula (I) weight and the dye representing the R1 is m- position of COOM in ratio 1: 0.6 to 1: contains in the range of 1.5 Claim 1 consisting of
The ink composition as described in the above. 3. The method according to claim 1, wherein the first dye group and the second dye group are contained in a weight ratio of 1: 0.1 to 1: 0.5. Ink composition. 4. M in the formula (I) represents a cation of a compound having volatility, and the formula (II) and / or the formula (III)
The ink composition according to any one of claims 1 to 3, wherein M in (4) is an alkali metal cation. 5. The ink composition according to claim 1, which comprises a nitrogen-containing cyclic compound and a polyhydric alcohol. 6. A dye represented by formula (I) defined in claim 1, wherein R ¹ is P at the m-position with respect to the azo group.
An ink composition comprising a dye representing O (OM) ₂ or COOM and a dye represented by the following formula (VI). Embedded image [In the formula, M has the same meaning as defined above, m represents 1 or 2, and n represents 0 or 1. ] 7. The dye according to claim 6, wherein the dye represented by the formula (I) and the dye represented by the formula (VI) are contained in a weight ratio of 4: 1 to 1:10. Ink composition. 8. An ink composition comprising at least a dye group A and a dye group B, wherein the dye group A is a dye represented by the formula (I) defined in claim 1. An ink composition comprising a dye represented by formula (VI) defined in claim 6, wherein dye group B is the second dye group defined in claim 1. 9. The method according to claim 8, wherein the dye represented by the formula (I) and the dye represented by the formula (VI) are contained in a weight ratio of 4: 1 to 1:10. Ink composition. 10. A dye group A comprising 1 to 20% by weight,
The ink composition according to claim 8 or 9. 11. The dye composition according to claim 8, wherein the weight ratio of the dye group A and the dye group B in the ink composition is in the range of 1: 0.1 to 1: 0.5. The ink composition described. 12. M in the formula (I) represents a cation of a volatile compound, and the formula (II) and / or the formula (II)
The ink composition according to any one of claims 8 to 11, wherein M in I) is an alkali metal cation. 13. The ink composition according to claim 8, which comprises a nitrogen-containing cyclic compound and a polyhydric alcohol. 14. The pH is adjusted to 8.5 to 11 with tri (hydroxyalkyl) amine.
The ink composition according to any one of 13 above. 15. The ink composition according to claim 1, which comprises at least one hydroxide selected from the group consisting of elemental period Ia metal elements. 16. The hydroxide is LiOH, NaOH,
The ink composition according to any one of claims 1 to 15, which is KOH. 17. A glycol ether in an amount of 3 to 30% by weight.
The ink composition according to any one of claims 1 to 16, which comprises the range of. 18. The ink composition according to claim 1, comprising a nonionic acetylene glycol-based surfactant in a range of 0.1 to 5% by weight. 19. The surface tension is 20 to 35 mN / m,
The ink composition according to any one of claims 1 to 15. 20. A recording method for depositing an ink composition to print on a recording medium, wherein the ink composition according to any one of claims 1 to 19 is used as the ink composition. 21. An ink jet recording method for ejecting droplets of an ink composition, adhering the droplets to a recording medium for printing, wherein the ink composition is any one of claims 1 to 19. An inkjet recording method using the described ink composition. 22. A recorded matter recorded by the recording method according to claim 20 or 21.