JP2020055985A - Ink, ink container, inkjet recording device and recording method - Google Patents

Abstract

To provide an ink capable of obtaining an excellent color development not only on plain paper but also on commercial printing paper, while excellent in shelf stability and discharge stability, the ink having high drying properties and capable of recording at good quality in which beading is suppressed.SOLUTION: An ink includes a pigment, a quinacridone derivative expressed by a general formula (1) below, and a solvent A with an SP value of 9.0 or more, 11.0 or less. A content of the solvent A is less than 10 mass% (In the formula, R, R, R, and Reach denote a hydrogen atom, a halogen atom or an alkyl group having 1-4 carbon atoms, and may be the same or different. Rand Reach denote an alkyl group having 1-4 carbon atoms, and may be the same or different. m and n denote an integer of 0-2, except that m and n are simultaneously 0).SELECTED DRAWING: None

Description

  The present invention relates to an ink, an ink container, an ink jet recording apparatus, and a recording method.

  The inkjet recording method is popular because it has the advantage that the process is simpler than other recording methods, full color can be easily achieved, and an image having a high resolution can be obtained even with a device having a simple configuration. It is expanding from personal to office applications, commercial printing and industrial printing. In such an ink jet recording method, a water-based ink composition using a water-soluble dye as a coloring material is mainly used, but has a drawback that it has poor water resistance and light resistance. Pigment inks using the above pigments are being developed.

  In inkjet printing for office use, plain paper is mainly used as a recording medium, and a high image density is required. Generally, when a pigment ink is printed on plain paper, the pigment penetrates into the paper without remaining on the paper surface, so that the pigment density on the paper surface is reduced and the image density is reduced. Increasing the pigment concentration in the ink increases the image density, but increases the viscosity of the ink and decreases the ejection stability.

As a measure against high-speed printing, in order to increase the drying speed of the ink attached to the recording medium, a means for increasing the drying speed has been taken by adding a penetrant such as a hydrophobic solvent to the ink and allowing water to penetrate into the recording medium. I have.
It is required to satisfy the dispersion stability under the environment of both the pigment dispersion of the water solvent and the ink of the hydrophobic solvent.

  In addition, the aqueous pigment ink used in the above-described ink jet recording system or writing instrument, unlike an aqueous dye ink prepared by dissolving a dye in water, it is necessary to stably disperse a pigment that does not dissolve in water in water for a long time. Therefore, various pigment dispersions have been developed.

For example, Patent Document 1 discloses a quinacridone pigment (a) and an anionic group-containing organic polymer compound as a method for producing an aqueous pigment dispersion in which a pigment is stably dispersed and a good dispersion state can be maintained even during long-term storage. A mixture containing (c), a basic compound (d), a water-soluble organic compound (e) having a hydrogen bond term δh of 7 to 13 in the solubility parameter, and a quinacridone-based pigment derivative (b) is kneaded and mixed at room temperature. A method for producing an aqueous pigment dispersion having a kneading step of producing a solid pigment dispersion and a mixing step of mixing an aqueous medium with the pigment dispersion is disclosed.
In addition, Patent Document 2 includes a mixture of a quinacridone compound having a novel specific structure that is both effective in achieving excellent storage stability of a pigment dispersion and ink and that is effective in realizing an aqueous ink having excellent ejection stability. An ink is disclosed.
Further, Patent Literature 3 discloses an ink containing at least a pigment, a wax, a water-soluble solvent, and water, wherein the water-soluble solvent includes a solvent having an SP value of 9.0 or more and 11.0 or less. The ratio (by mass) of the content of the wax to the content of the solvent having an SP value of 9.0 or more and 11.0 or less is in the range of 1.0: 2.5 to 1.0: 25.0. Are disclosed. It is described that this ink has high image density and high chroma, but also has excellent scratch resistance of the image, and also has excellent storage stability and ejection stability.

  An object of the present invention is to provide an ink which is excellent in storability and capable of performing recording with suppressed beading.

（式中、Ｒ¹，Ｒ²，Ｒ³およびＲ⁴は水素原子、ハロゲン原子、または炭素数１〜４のアルキル基を表し、同一でも異なっていてもよい。また、Ｒ⁵およびＲ⁶は炭素数１〜４のアルキル基を表し、同一でも異なっていてもよい。ｍ、ｎは０〜２の整数を表す。ただし、ｍ、ｎが同時に０である場合を除く。） The above problem is solved by the following <1> invention.
<1> A pigment, a quinacridone derivative represented by the following general formula (1), and a solvent A having an SP value of 9.0 or more and 11.0 or less, and the content of the solvent A is less than 10% by mass. ink.

^{(Wherein, R 1, R 2, R} 3 and R ⁴ are a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. Also, R ⁵ and R ⁶ Represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different, and m and n represent integers of 0 to 2, provided that m and n are not 0 simultaneously.

According to the present invention, it is possible to provide an ink which is excellent in storability and capable of recording with beading suppressed.

FIG. 1 is a perspective view schematically illustrating an example of a recording apparatus according to the invention. FIG. 2 is a perspective view schematically illustrating an example of an ink container according to the present invention.

In the ink of the present invention, a solvent having an SP value of 9.0 or more and 11.0 or less (hereinafter referred to as solvent A) is used.
When a solvent A having an SP value of 9.0 or more and 11.0 or less is mixed as a solvent with the ink, and when the ink is applied to a coated paper, the residual solvent is reduced in an image area on the coated layer of the coated paper. The effect of suppressing the occurrence of beading can be obtained. However, on the other hand, the solvent A passes through the coat layer and reaches the cellulose layer even on a recording medium having a low water absorption such as coated paper, so that the solvent remaining in the cellulose layer even after heating and drying is reduced. It is difficult to do. For this reason, a problem called blocking occurs in which an image is transferred to the overlapped paper due to the effect of the solvent remaining in the cellulose layer when the printed matter is stacked. In addition, the solvent A affects the storage stability of the ink dispersed using the quinacridone derivative represented by the general formula (1). When the amount exceeds 10% by mass with respect to the ink, the dispersion becomes unstable, It also has an adverse effect on ejection using an ink jet, which can cause deterioration in image quality such as color developability.
Pigments are difficult to disperse, and even if dispersed only with a dispersing resin, there may be a problem in storage stability. However, when the quinacridone derivative represented by the general formula (1) and a water-soluble solvent having an SP value of 9.0 or more and 11.0 or less are used in combination and dispersed, storage stability and ejection stability are good. By controlling the water-soluble solvent having an SP value of 9.0 or more and 11.0 or less to less than 10% by mass, beading is suppressed, drying property is high, and blocking is achieved. It has been found that by being able to prevent this, it is possible to obtain an ink capable of printing with good quality.
Based on such facts, the present inventors have invented the ink of the present invention having excellent color-forming properties, stability and drying properties even for coated paper used for commercial printing paper.

  Hereinafter, the present invention <1> will be described in detail. However, embodiments thereof include the following <2> to <13>, and these will also be described together.

<2> The ink according to <1>, wherein the content of the solvent A is 2% by mass or more and 8% by mass or less.
<3> The ink according to <1> or <2>, wherein the content of the quinacridone derivative with respect to the pigment is 1% by mass or more and 10% by mass or less.
<4> The ink according to any one of <1> to <3>, wherein the content of the quinacridone derivative in the ink is 0.01% by mass or more and 1.00% by mass or less based on the total amount of the ink.
<5> The ratio of the content of the solvent A to the content of the quinacridone derivative in the ink and the content of the solvent A (the quinacridone derivative / the solvent A) is from 0.045 to 0.18 and is from <1> to <4>. The ink according to any of the above.
<6> The solvent A according to <1> to <5>, wherein the solvent A is at least one selected from 3-ethyl-3-hydroxymethyloxetane, isopropylideneglycerol, and N, N-dimethyl-β-butoxypropionamide. The ink according to any of the above.
<7> The ink according to any one of <1> to <6>, wherein the pigment is a quinacridone pigment.
<8> The pigment is C.I. I. Pigment Red 122, C.I. I. Pigment Violet 19, C.I. I. Pigment Red 122 and C.I. I. Pigment Violet 19, or C.I. I. Pigment Red 202 and C.I. I. The ink according to any one of <1> to <7>, which is a mixed crystal of CI Pigment Violet 19.
<9> The ink according to any one of <1> to <8>, wherein the ink further contains a resin emulsion, and the resin emulsion is made of an acrylic resin or a urethane resin.
<10> The ink according to any one of <1> to <9>, wherein the ink further contains a polyethylene wax.
<11> The ink according to any one of <1> to <10>, wherein the ink further contains a polyether-modified siloxane compound.
<12> An ink container containing the ink according to any one of <1> to <11> in a container.
<13> An ink jet recording apparatus comprising: the ink container according to <12>; and an ejection unit that ejects ink supplied from the ink container.
<14> A recording method including an ink applying step of applying the ink according to any one of <1> to <11> to a recording medium.

（式中、Ｒ¹，Ｒ²，Ｒ³およびＲ⁴は水素原子、ハロゲン原子、または炭素数１〜４のアルキル基を表し、同一でも異なっていてもよい。また、Ｒ⁵およびＲ⁶は炭素数１〜４のアルキル基を表し、同一でも異なっていてもよい。ｍ、ｎは０〜２の整数を表す。ただし、ｍ、ｎが同時に０である場合を除く。） The ink of the present invention contains a pigment, a quinacridone derivative represented by the following general formula (1), and a solvent A having an SP value of 9.0 or more and 11.0 or less, and the content of the solvent A is 10% by mass. Is less than.

^{(Wherein, R 1, R 2, R} 3 and R ⁴ are a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. Also, R ⁵ and R ⁶ Represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different, and m and n represent integers of 0 to 2, provided that m and n are not 0 simultaneously.

The quinacridone derivative represented by the general formula (1) can be obtained as a quinacridone derivative mixture by the reactions shown in the following reaction formulas (1) and (2).
First, as shown in the following reaction formula (1), the quinacridone compound (A-1) was reacted with an excessive amount of chlorosulfonic acid in the absence of a solvent, and washed with water to replace the chlorosulfonic acid group and the sulfonic acid group. A quinacridone mixture (A-2) is obtained. Next, as shown in the reaction formula (2), the above (A-2) is reacted with a dialkylamine to obtain a quinacridone derivative mixture (A-3). The quinacridone derivative mixture thus obtained by the reaction contains the quinacridone derivative in the case where m = 1 and n = 1 in the general formula (1). In addition, in the quinacridone derivatives represented by m = 1 and n = 1 in the general formula (1), there are quinacridone derivatives having different substitution positions of a sulfonic acid group and a dialkylaminosulfonic acid group, and a mixture thereof. Is also good.
In the present invention, the quinacridone derivative represented by the general formula (1) may be a mixture, and a quinacridone derivative mixture obtained by the above method can be used.

It can be confirmed by mass spectrometry, for example, that the quinacridone derivative mixture contains the quinacridone derivative in the case where m = 1 and n = 1 in the general formula (1).
For example, when the obtained quinacridone derivative mixture has a positive molecular ion peak of 556.1 ± 0.1 and a negative ion molecular peak of 554.1 ± 0.1 in mass spectrometry, the substitution position is Although it cannot be specified, it is confirmed that quinacridone compounds represented by the following formula and in which m = 1 and n = 1 are mixed. Further, when a positive molecular ion peak is found at 611.2 in positive ion measurement, it is understood that a quinacridone compound represented by the following formula and having m = 2 and n = 0 is also present.
In mass spectrometry, mass accuracy and resolution differ depending on the device, but “± 0.1” here indicates an error range of this mass spectrometry. If it falls within this range, it is assumed that the quinacridone derivative of m = 1 and n = 1 in the present invention has been identified.

Whether or not the quinacridone derivative represented by the general formula (1) is contained in the ink can be determined, for example, as follows.
First, it is separated into other components of the ink and a pigment component containing a quinacridone derivative. Components dissolved in the ink are separated by centrifugal sedimentation or ultrafiltration, and components dispersed in the ink (such as a fixing resin) and components such as a dispersed resin adhered (adsorbed) to the pigment are Dissolve and remove them with a solvent that dissolves them. This operation also depends on the material contained in the ink. After separating the quinacridone derivative and the pigment from the other components in the ink, the quinacridone derivative represented by the general formula (1) is detected by the amount of the functional group containing sulfur by a gas chromatograph mass spectrometer (GC-MS). It is possible to

<Ink>
Hereinafter, organic solvents, water, coloring materials, resins, additives, and the like used in the ink will be described.

-Coloring material-
In the present invention, a pigment is used as a coloring material. Examples of the pigment include a surfactant-dispersed pigment in which a pigment is dispersed with a surfactant, a resin-dispersed pigment in which a pigment is dispersed with a resin, a resin-coated pigment in which the surface of a pigment is coated with a resin, and a self-coated pigment in which a hydrophilic group is provided on the pigment surface. Although there are dispersed pigments and the like, water-dispersible pigments are preferred.

The ink of the present invention is preferably a magenta ink.
Examples of the pigment include an azo pigment, a polycyclic pigment, a dye chelate, a nitro pigment, a nitroso pigment, and the like. Among these, polycyclic pigments and the like are preferable, and quinacridone pigments are particularly preferable.
Examples of the pigment include C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 150, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 209, 219, C. I. Pigment Violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38 and the like. Quinacridone pigments are preferred, and C.I. I. Pigment Red 122, C.I. I. Pigment Violet 19, C.I. I. Pigment Red 122 and C.I. I. Pigment Violet 19, or C.I. I. Pigment Red 202 and C.I. I. Pigment Violet 19 is more preferable.

The BET specific surface area of the pigment used is preferably about 10 m ² / g or more and about 1500 m ² / g, more preferably about 20 m ² / g or more and about 600 m ² / g or less, further preferably about 50 m ² / g or more. It is 300 m ² / g or less.
If the desired specific surface area is not readily available, a general size reduction or milling process (eg, ball milling, jet milling, sonication) is performed to reduce the pigment to a relatively small particle size. Good.
The volume average particle diameter (D50) of the water-dispersible pigment is preferably from 10 nm to 200 nm in the ink.

  The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass from the viewpoints of improving image density, good fixability and ejection stability. It is as follows.

  In the present invention, a dye may be used in combination for the purpose of adjusting the color tone, but it is necessary to use the dye within a range that does not deteriorate the weather resistance.

-Pigment derivative-
In order to disperse the pigment in water, a pigment derivative having a hydrophilic group bonded thereto may be used.When dispersing the pigment using a dispersant or the like, a small amount of the pigment derivative is added to the pigment to form a mill. Alternatively, a dispersion can be prepared by kneading. The use of a pigment derivative can enhance the stability of the dispersion, and a high effect can be expected by adding a small amount of the pigment derivative. Even if the structure of the hydrophobic part of the pigment and the pigment derivative used in the dispersion liquid is different, it is possible to obtain a sufficient adsorptive power and it is possible to obtain sufficient storage stability. If the parts have the same structure, the adsorptive power is higher and the pigment derivative is less likely to be peeled off when adsorbed on the pigment surface, so that higher storage stability can be obtained. In the present invention, the quinacridone derivative represented by the general formula (1) is used as the pigment derivative, and the addition amount is preferably 1% by mass or more and 10% by mass or less with respect to the pigment, and more preferably, with respect to the pigment. It is 2% by mass or more and 8% by mass or less.
The content of the quinacridone derivative represented by the general formula (1) in the ink is preferably 0.01% by mass or more and 1.00% by mass or less based on the total amount of the ink. When the content is 0.01% by mass or more, sufficient storage stability and ejection stability can be obtained. When the content is 1.00% by mass or less, the saturation of the printed matter does not decrease.
Further, the ratio of the content of the quinacridone derivative in the ink to the content of the solvent A (the quinacridone derivative / the solvent A) is preferably 0.045 or more and 0.18 or less, and is within the above range. And high storage stability can be obtained.
When the ink contains the quinacridone derivative represented by the general formula (1) as a mixture, the content of the quinacridone derivative represented by the general formula (1) is represented by the content represented by the general formula (1). And the total content of the quinacridone derivative represented by the general formula (1).

-Pigment dispersant-
The dispersant used in the present invention is not particularly limited, and can be appropriately selected from the dispersants used for preparing the pigment dispersion according to the purpose.
For example, nonionic surfactants such as polyoxyethylene isodecyl ether, polyoxyethylene lauryl ether, polyoxyethylene-β-naphthyl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene distyryl phenyl ether, or polyoxyethylene Ethylene lauryl ether sulfate, polyoxyethylene-β-naphthyl ether sulfate, polyoxyethylene styryl phenyl ether phosphonate, polyoxyethylene distyryl phenyl carboxylate, lauryl ether phosphonate, octyl ether carboxylate, An anionic surfactant such as styrylphenyl ether sulfate, styrylphenyl ether phosphonate, and β-naphthyl ether carboxylate can be used as a dispersant.

-Copolymer-
In the present invention, a copolymer can be used as a pigment dispersant.
As the copolymer, an acrylic acid-based copolymer, a vinyl-based copolymer, a polyester-based copolymer, and a polyurethane-based copolymer can be used. Here, the acrylic acid-based copolymer refers to a copolymer using an acrylic acid derivative monomer and / or a methacrylic acid derivative monomer.

Further, the present invention can have a repeating unit composed of a polymerizable monomer, can be appropriately selected according to the purpose without particular limitation, for example, a polymerizable hydrophobic monomer, a polymerizable hydrophilic monomer, And a polymerizable surfactant.
The hydrophobic monomer is not particularly limited, but is an unsaturated ethylene monomer having an aromatic ring such as benzyl (meth) acrylate, styrene, α-methylstyrene, 4-t-butylstyrene, 4-chloromethylstyrene; Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, dimethyl maleate, dimethyl itaconate, dimethyl fumarate, lauryl (meth) acrylate, tridecyl (meth) acrylate, (meth) ) Tetradecyl acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, henycosyl (meth) acrylate, (meth) Alkyl (meth) acrylate such as docosyl acrylate 1-heptene, 3,3-dimethyl-1-pentene, 4,4-dimethyl-1-pentene, 3-methyl-1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene, 1 -Octene, 3,3-dimethyl-1-hexene, 3,4-dimethyl-1-hexene, 4,4-dimethyl-1-hexene, 1-nonene, 3,5,5-trimethyl-1-hexene, An alkyl group such as -decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 1-docose, etc. And the like, and two or more kinds thereof may be used in combination.

  Examples of the hydrophilic monomer include, but are not particularly limited to, (meth) acrylic acid or a salt thereof, maleic acid or a salt thereof, monomethyl maleate, itaconic acid, monomethyl itaconate, fumaric acid, 4-styrenesulfonic acid, and 2-acrylamide- Anionic unsaturated ethylene monomers such as 2-methylpropanesulfonic acid, 2-methacryloxyethyl acid phosphoate, 1-methacryloxyethane-1,1-diphosphonic acid; 2-hydroxyethyl (meth) acrylate, diethylene glycol mono (Meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, N-bi Non-ionic non-ionic compounds such as chloroformate, N-vinylacetamide, N-vinylpyrrolidone, acrylamide, N, N-dimethylacrylamide, Nt-butylacrylamide, N-octylacrylamide, Nt-octylacrylamide, and diacetoneamide Saturated ethylene monomers and the like may be mentioned, and two or more kinds may be used in combination.

  Examples of the polymerizable surfactant include an anionic or nonionic surfactant having at least one or more radically polymerizable unsaturated double bond group in a molecule.

Examples of the anionic surfactant, ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ hydrocarbon compound having a sulfate group and an allyl group (-CH ₂ -CH = CH _2), such as, ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ sulfate group and methacrylic group, such as _{[-CO-C (CH 3) =} CH 2 ] a hydrocarbon compound having, or ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ sulfate, such as base and 1 - an aromatic hydrocarbon compound having a propenyl group (-CH = CH ₂ CH ₃₎ and the like. Specific examples thereof include Eleminol JS-20 and RS-300 manufactured by Sanyo Kasei Co., Ltd., Aqualon KH-10, Aqualon KH-1025, Aqualon KH-05, Aqualon HS-10, Aqualon HS-10 manufactured by Daiichi Kogyo Seiyaku. -1025, Aqualon BC-0515, Aqualon BC-10, Aqualon BC-1025, Aqualon BC-20, Aqualon BC-2020 and the like.

The non-ionic surfactant, 1-propenyl (-CH = CH ₂ CH ₃₎ and polyoxyethylene group _{[- (C 2 H 4 O)} n-H ] a hydrocarbon compound or an aromatic having And hydrocarbon compounds. Specific examples thereof include Aqualon RN-20, Aqualon RN-2025, Aqualon RN-30, and Aqualon RN-50 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Latemul PD-104, Latemul PD-420, and Latemul PD manufactured by Kao Corporation. -430 and Latemul PD-450.

The copolymer is obtained by reacting a monomer component with a solvent in a flask equipped with a stirrer, a thermometer and a nitrogen inlet tube at a temperature of about 50 ° C. or more and 150 ° C. or less under nitrogen gas reflux in the presence of a polymerization initiator. Can be The viscosity of the aqueous solution or aqueous dispersion of the synthesized copolymer can be adjusted by changing the molecular weight, and the monomer concentration, the amount of polymerization initiator, the polymerization temperature, and the polymerization time during polymerization may be changed.
Regarding the polymerization temperature, a low molecular weight copolymer tends to be obtained when polymerized at a high temperature for a short time, and a high molecular weight copolymer tends to be easily obtained when polymerized at a low temperature for a long time. As for the content of the polymerization initiator, a higher content tends to easily obtain a low molecular weight copolymer, and a lower content tends to easily obtain a high molecular weight copolymer. Regarding the monomer concentration at the time of the reaction, a high concentration tends to easily obtain a low molecular weight copolymer, and a low concentration tends to easily obtain a high molecular weight copolymer. The weight average molecular weight of the copolymer is not particularly limited and may be appropriately selected depending on the intended purpose. However, the weight average molecular weight is preferably from 3,000 to 60,000, more preferably from 4,000 to 50,000, and more preferably from 5,000 to 50,000. It is more preferably from 3,000 to 30,000. When the weight average molecular weight is within the preferred range, it is advantageous in that, when used in an ink for inkjet recording, dispersion stability and ejection stability are improved.
The weight average molecular weight can be measured, for example, by gel permeation chromatography (GPC).

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of polyhydric alcohols include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butane Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3- Hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, and the like.
Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether.
Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, and the like. No.
Examples of the amide include formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, and 3-butoxy-N, N-dimethylpropionamide.
Examples of amines include monoethanolamine, diethanolamine, and triethylamine.
Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol and the like.
Other organic solvents include propylene carbonate, ethylene carbonate and the like.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or less, because it not only functions as a wetting agent but also provides good drying properties.

As the organic solvent, a polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Specific examples of the glycol ether compound include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;

  A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve ink permeability when paper is used as a recording medium.

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected depending on the intended purpose. The content is more preferably from 20% by mass to 60% by mass.

  The ink of the present invention contains at least one solvent A having an SP value of 9.0 or more and 11.0 or less. As a result, the wettability to the recording medium is improved, and the ink component penetrates into a commercial printing paper such as a coated paper having a coating layer and poor ink absorbency, thereby making it possible to suppress beading.

なお式（１）において、ΔＥ：凝集エネルギー密度、Ｖ：モル体積、Δｅ_ｉ：原子または原子団の蒸発エネルギー、Δｖ_ｉ：原子または原子団のモル体積、である。 The SP value is a solubility parameter, and is generally and widely used as an index of the affinity and solubility of a material such as a solvent, a resin, or a pigment, which is dissolved or dispersed in water or a solvent. Various methods have been proposed for obtaining the SP value, such as a method of measuring by experiment, a method of calculating from measurement of physical properties such as immersion heat, and a method of calculating from a molecular structure. In the present invention, Fedors proposed. A method of calculating from the molecular structure is used. This method is effective in that the SP value can be calculated if the molecular structure is known, and the difference between the experimentally measured value is small. In Fedors method, defined evaporation energy .DELTA.e i at 25 ° C. of each atom or atomic _group, the molar volume Delta] v _i as shown in the table below, this value can be determined SP value by substituting the equation (1) . In the present invention, the SP value at 25 ° C. is used, and temperature conversion and the like are not performed.

Note in the formula (1), Delta] E: cohesion energy density, V: molar volume, .DELTA.e _i: atom or group of evaporation energy, Delta] v _i: molar volume of atom or atomic group is.

For example, the SP value of isopropylidene glycerol (iPDG) is calculated as follows from the values in Table 1 below.
SP value = (14150 / 139.8) ^1/2 = 10.1 (cal / cm ³ ) ^1/2

As the solvent A, a water-soluble solvent is preferable, and in particular, 3-ethyl-3-hydroxymethyloxetane (SP value: 10.7), isopropylideneglycerol (SP value: 9.8) and N, N-dimethyl-β-butoxy Propionamide (SP value 9.8) is preferred. These solvents have excellent drying properties.
Organic solvents having an SP value of less than 9.0 generally have very low solubility in water and are liable to cause separation. In addition, organic solvents having an SP value of more than 11.0 deteriorate drying properties and beading. Due to the tendency, the ink cannot be constituted only by these solvents, and must be used by mixing with a solvent A having an SP value of 9.0 or more and 11.0 or less.
The content of the solvent A having an SP value of 9.0 or more and 11.0 or less is less than 10% by mass of the whole ink, and preferably 2 to 8% by mass. When the content is 2% by mass or more, the effect of suppressing beading is further improved. When the content is less than 10% by mass, the ejection stability does not deteriorate due to an increase in the viscosity of the ink, and the content is more preferably 8% by mass or less.
By using a gas chromatograph mass spectrometer (GC-MS), an organic compound containing a solvent can be quantified, and the content of the solvent A in the ink can be obtained.

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of drying properties and ejection reliability of the ink, the content is preferably from 10% by mass to 90% by mass, and more preferably from 20% by mass. % Or more and 60% by mass or less.

-Resin emulsion A resin emulsion having excellent film forming properties (image forming properties) and high water repellency, high water resistance, and high weather resistance has high water resistance and high image density (high color developing property). It is useful for image recording and includes, for example, condensation-type synthetic resins, addition-type synthetic resins, and natural polymer compounds.
Examples of the condensation-based synthetic resin include a polyester resin, a polyurethane resin, a polyepoxy resin, a polyamide resin, a polyether resin, a poly (meth) acrylic resin, an acryl-silicone resin, and a fluorine-based resin. Examples of the additional synthetic resin include a polyolefin resin, a polystyrene resin, a polyvinyl alcohol resin, a polyvinyl ester resin, a polyacrylic acid resin, and an unsaturated carboxylic acid resin. Examples of the natural polymer compound include celluloses, rosins, and natural rubber. As the resin emulsion, a resin emulsion having a hydrophilic group and self-dispersibility, and a resin itself having no dispersibility and having a dispersibility imparted by a surfactant or a resin having a hydrophilic group can be used. Among these, a polyacryl resin or a polyurethane resin is particularly preferable, and two or more of the above resin emulsions may be used in combination.
In the case of emulsion polymerization of unsaturated monomers, a resin emulsion is reacted by adding unsaturated monomers, a polymerization initiator, a surfactant, a chain transfer agent, a chelating agent, and a pH adjuster in water. Therefore, a water-dispersible resin can be easily obtained, the resin composition can be easily changed, and desired properties can be easily obtained.

  The resin emulsion is strongly alkaline, and under strong acidic conditions, the molecular chain is ruptured such as dispersion destruction or hydrolysis, so the pH is preferably 4 or more and 12 or less, particularly from the viewpoint of miscibility with the water-dispersible colorant. 6 or more and 11 or less are more preferable, and 7 or more and 10 or less are still more preferable.

  The average particle size (D50) of the resin emulsion is related to the viscosity of the dispersion, and the smaller the particle size of the same composition, the higher the viscosity at the same solid content. The average particle diameter (D50) of the water-dispersible resin is preferably 50 nm or more so that the ink does not become excessively high in viscosity. Further, when the particle size is several tens of μm, it cannot be used because it becomes larger than the nozzle opening of the inkjet head. If particles having a larger particle diameter than the nozzle port are present in the ink, the ejection performance is deteriorated. Therefore, the average particle diameter (D50) is more preferably 200 nm or less, and still more preferably 150 nm or less, so as not to impair the ink ejection property.

Further, the resin emulsion has a function of fixing the water-dispersible colorant on the paper surface, and has a function of forming a film at ordinary temperature to improve the fixability of the colorant. Therefore, the minimum film forming temperature (MFT) of the resin emulsion is preferably 30 ° C. or less. Further, when the glass transition temperature is -40 ° C or lower, the viscosity of the resin film becomes strong and the printed matter is tacky. Therefore, the glass transition temperature is preferably -30 ° C or higher.
The content of the resin emulsion in the ink is preferably 0.5% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 8% by mass or less.

-Wax-
The ink according to the present invention may include a wax, and the wax may be water-soluble or water-dispersible. As the water-soluble wax, a wax having a hydrophilic group such as a hydroxyl group, a carboxyl group, an ethylene oxide group, and an amine group, and as the water-dispersible wax, a wax emulsion can be mainly used.

  Specifically, petroleum waxes such as carnauba wax, candelilla wax, beeswax, rice wax, lanolin, etc., plant waxes, animal waxes, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, polyethylene oxide wax, petrolatum, etc. Mineral waxes such as wax, montan wax and ozokerite, synthetic waxes such as carbon wax, Hoechst wax, polyethylene wax and stearamide, natural and synthetic wax emulsions such as α-olefin / maleic anhydride copolymers and compounded waxes Can be used alone or in combination of two or more. Further, other latexes, colloid solutions, suspensions and the like can also be used. In the present invention, a polyethylene wax having good solubility and dispersibility with a water-soluble solvent is desirable.

  Commercially available waxes can be used, and specific examples thereof include Cerozol 524 (carnauba wax, melting point: 83 ° C., particle size: 200 nm, manufactured by Chukyo Yushi), HYTEC E-6500 (polyethylene wax, melting point: 140 ° C, particle size 60 nm, manufactured by Toho Chemical Co., Ltd., HYTEC E-8237 (polyethylene wax, melting point 106 ° C, particle size 80 nm, manufactured by Toho Chemical), HYTEC P-9018 (polypropylene wax, melting point 156 ° C, particle size 60 nm, Toho Chemical Co., Ltd.) Nopcoat PEM-177 (polyolefin wax, melting point 105 ° C., particle size 10 nm, manufactured by San Nopco), AQUACER 498 (paraffin wax, melting point 58 ° C., manufactured by Big Chemie Japan), AQUACER535 (mixed wax, melting point 95 ° C., big) Chemie Japan AQUACER531 (polyethylene wax, melting point 130 ° C., particle size 123 nm, manufactured by Big Chemie Japan), AQUACER515 (polyethylene wax, melting point 135 ° C., particle size 33 nm, manufactured by Big Chemie Japan), and the like.

  The melting point of the wax is preferably in the range of 70 ° C to 170 ° C, more preferably 100 ° C to 140 ° C. If the melting point is 70 ° C. or higher, the image is not sticky, and no image transfer occurs even when the images are superimposed. When the melting point is 170 ° C. or lower, the image is melted by frictional heat when the image is rubbed, and a slip property is obtained, so that the image has good scratch resistance.

  The volume average particle diameter of the wax is preferably 200 nm or less, more preferably 20 nm or more and 150 nm or less. When it is 200 nm or less, good ejection can be obtained without being caught by a nozzle or a filter in a head.

  The amount of wax solids added to the ink is preferably in the range of 0.05% by mass to 2% by mass, and more preferably 0.1% by mass to 0.5% by mass. When the amount of addition is 0.1% by mass or more, slipperiness can be imparted to the image surface after printing, and the scratch resistance of the image can be maintained high. Further, when the addition amount is 0.5% by mass or less, the wax can be dissolved or dispersed in the solvent in the ink, so that the wax does not precipitate and adhere to the head, so that the ink droplet is ejected favorably. It becomes possible.

-Surfactant-
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
Surfactants are roughly classified into anionic surfactants, nonionic surfactants, and amphoteric surfactants according to hydrophilic groups, and are generally classified into fluorine-based surfactants, acetylene-based surfactants, and the like according to hydrophobic groups. it can.

  Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, and polyoxyethylene alkyl ether sulfate.

  Examples of the nonionic surfactant include polyol, glycol ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, and polyoxyethylene. Alkyl amide, acetylene glycol and the like can be mentioned.

The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the purpose.
Among them, those which do not decompose even at a high pH are preferable, and examples thereof include side-chain-modified polydimethylsiloxane, both-end-modified polydimethylsiloxane, one-end-modified polydimethylsiloxane, and both-chain-end both-end modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. In addition, a polyether-modified silicone-based surfactant can also be used as the silicone-based surfactant, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.

Examples of the fluorine-based surfactant include a perfluoroalkylsulfonic acid compound, a perfluoroalkylcarboxylic acid compound, a perfluoroalkylphosphate ester compound, a perfluoroalkylethylene oxide adduct, and a perfluoroalkylether group in a side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid and perfluoroalkylsulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain include a sulfate salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in a side chain, and having a perfluoroalkyl ether group in a side chain. Salts of a polyoxyalkylene ether polymer are exemplified. Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) _{3 and the} like.

  Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, and the like.

  Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.

Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, and polyoxyethylene alkyl ether sulfate.
These may be used alone or in combination of two or more.

（上記式中、Ｒ５は、水素原子又は炭素数１〜４のアルキル基を表し、ｍは０〜２３の整数、ｎは１〜１０の整数、ａは１〜２３の整数、ｂは０〜２３の整数を表す。） -Polyether-modified siloxane compound-
As a material of the ink used in the present invention, a polyether-modified siloxane compound as a surfactant can be used. As a result, the ink is hardly wetted by the ink repellent layer of the head nozzle plate, and the ejection failure due to the adhesion of the ink nozzles is prevented, and the ejection stability is improved. Further, the ink hardly adheres to the surface of the nozzle ink repellent layer, which is particularly liable to cause a problem, and the ink hardly causes ejection failure. Among them, those represented by the following general formula (2) are preferable, and in particular, the dispersion stability is not impaired by the combination of the water-dispersible coloring material and the organic solvent, the dynamic surface tension is low, and the permeability and leveling property are low. Are preferred. These polyether-modified siloxane compounds may be used alone or as a mixture of two or more.

(In the above formula, R5 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, m is an integer of 0 to 23, n is an integer of 1 to 10, a is an integer of 1 to 23, b is 0 to Represents an integer of 23.)

Examples of the compound represented by the general formula (2) include compounds represented by the following formulas (2-1) to (2-3).

  Further, commercially available polyether-modified siloxane compound surfactants having the same effect as the above compounds include 71 ADDIVE, 74 ADDITIVE, 57 ADDITIVE, 8029 ADDITIVE, 8054 ADDITIVE, 8211 ADDITIVE, 8019 ADDITIVE, and 8526 ADDITIVE manufactured by TORAY Dow Corning. 2213, FZ-2191, TSF4440, TSF4441, TSF4445, TSF4446, TSF4450, TSF4452, TSF4460, manufactured by Momentive Performance Materials, Sylface SAG002, Sylface SAG003, Sylface SAG005, manufactured by Nissin Chemical Industry Co., Ltd. Sylface SAG503A, Sylface SAG0 8, Sylface SJM003, TEVO_Wet_KL245, TEGO_Wet_250, TEGO_Wet_260, TEGO_Wet_265, TEGO_Wet_270, TEGO_Wet_280, BYK-345, BYK-BYK, BYK-347, BYK-347, BYK-Japan, etc., manufactured by Evonik Co., Ltd. Is mentioned.

  If necessary, the above-mentioned polyether-modified siloxane compound surfactant may be used in combination with a fluorine-based surfactant, a silicone-based surfactant, an acetylene glycol or an acetylene alcohol-based surfactant.

  The content of the surfactant in the ink is preferably from 0.001% by mass to 5% by mass, more preferably from 0.5% by mass to 3% by mass. When the content is 0.001% by mass or more, the effect of adding the surfactant can be obtained. However, if it exceeds 5 mass, the effect of addition is saturated, so that it is meaningless to increase the amount.

-Other components-
In addition to the above components, various known additives may be added to the ink of the present invention, if necessary. Examples include penetrants, foam inhibitors (defoamers), pH adjusters, preservatives and fungicides, chelating agents, rust inhibitors, antioxidants, ultraviolet absorbers, oxygen absorbers, light stabilizers, etc. Is mentioned.

（上記式中、Ｒ′はメチル基又はエチル基、Ｒ″は水素又はメチル基、Ｒ″′はエチル基又はプロピル基である。） <Penetrant>
As the penetrant, at least one non-wetting agent polyol compound or glycol ether compound having 8 to 11 carbon atoms is preferable. Here, the non-wetting agent property means having a solubility of not less than 0.2% by mass and not more than 5.0% by mass in water at 25 ° C. Among these penetrants, a 1,3-diol compound represented by the following general formula (3) is preferable, and 2-ethyl-1,3-hexanediol [solubility: 4.2% (25 ° C.)], , 2,4-trimethyl-1,3-pentanediol [solubility: 2.0% (25 ° C)] is particularly preferred.

(In the above formula, R ′ is a methyl group or an ethyl group, R ″ is a hydrogen or a methyl group, and R ″ ″ is an ethyl group or a propyl group.)

Other non-wetting agent polyol compounds include, for example, 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1,3 -Propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-1 And aliphatic diols such as 2-diol.
The content of the penetrant in the ink is preferably 0.5% by mass or more and 4% by mass or less, more preferably 1% by mass or more and 3% by mass or less. When the content is 0.5% by mass or more, the effect of penetrating the ink is obtained, and the image quality is improved. If the content is 4% by mass or less, the ink is sufficiently dissolved in the ink, so that problems such as separation and an increase in the initial viscosity of the ink do not occur.

<Defoaming agent>
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, silicone-based antifoaming agents are preferred because of their excellent foam breaking effect.

<PH adjuster>
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

<Antiseptic / antifungal agent>
The preservative / antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

-Chelating reagent-
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uramildiacetate.

<Rust inhibitor>
The rust inhibitor is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

<Antioxidant>
Examples of the antioxidant include a phenol-based antioxidant (including a hindered phenol-based antioxidant), an amine-based antioxidant, a sulfur-based antioxidant, and a phosphorus-based antioxidant.

<Ultraviolet absorber>
Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex salt ultraviolet absorber.

-Manufacture of ink-
The ink of the present invention is produced by dispersing or dissolving the pigment, the quinacridone derivative, the organic solvent, water, and other optional components in an aqueous medium, and stirring and mixing as necessary. This stirring and mixing can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, and the like, and the stirring and mixing is performed by a stirrer using a general stirring blade, a magnetic stirrer, a high-speed disperser, or the like. be able to.

-Ink physical properties-
The physical properties of the ink of the present invention are not particularly limited and can be appropriately selected depending on the purpose.
However, if the static surface tension of the ink is 20 mN / m or more and the dynamic surface tension at a bubble life time of 15 msec by the maximum bubble pressure method is 34 mN / m or less, sufficient wettability to the recording medium is ensured. In spite of the fact that the ink can be used, it is difficult to wet the nozzle plate optool water-repellent film of the ink jet head, it is possible to secure the ejection stability, and the ink becomes extremely stable.
The viscosity of the ink at 25 ° C. is preferably from 5 mPa · s to 25 mPa · s, and more preferably from 6 mPa · s to 20 mPa · s. If it is 5 mPa · s or more, the effect of improving the print density and character quality can be obtained. If the pressure is 25 mPa · s or less, the ink ejection property can be ensured.
The viscosity can be measured at 25 ° C. using, for example, a viscometer (RE-550L, manufactured by Toki Sangyo Co., Ltd.).

The ink of the present invention, as an ink jet head, uses a piezoelectric element as a pressure generating means for pressurizing the ink in the ink flow path, and deforms a diaphragm that forms a wall surface of the ink flow path to change the volume in the ink flow path. So-called piezo-type (see JP-A-2-51734), or a so-called thermal-type in which bubbles are generated by heating ink in an ink flow path using a heating resistor (see JP-A-2-51734). Japanese Patent Application Laid-Open No. 61-59911), a diaphragm forming an ink flow path wall and an electrode are arranged to face each other, and the diaphragm is deformed by an electrostatic force generated between the diaphragm and the electrode. A printer equipped with any ink jet head, such as an electrostatic type (see JP-A-6-71882) that ejects ink droplets by changing the volume in an ink flow path. It is also good to use.
Further, the ink of the present invention may be used while housed in an ink housing container such as an ink cartridge.

<Ink storage container>
The ink container of the present invention contains the ink of the present invention in a container, and further includes other members appropriately selected as necessary.
The container is not particularly limited and its shape, structure, size, material and the like can be appropriately selected depending on the purpose.For example, an aluminum laminated film, an ink storage portion formed of a resin film or the like can be used. Those having at least one are preferred.

<Recording medium>
The recording medium on which recording can be performed using the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, plain paper, glossy paper, special paper, cloth, film, OHP Sheets, general-purpose printing paper, and the like. However, the ink of the present invention is very excellent in that good recording is possible on commercial printing paper like other papers.
The commercial printing paper referred to here is a printing paper having a coating layer on at least one surface of a support, for example, a printing paper using a filler such as calcium carbonate or kaolin as a coating layer material. No. Further, in a print-coated paper, which is an example of commercial printing paper, a coating layer is made of a white pigment such as clay (kaolin) or calcium carbonate and an adhesive (binder) such as starch.

A recorded matter having an image formed by using the ink of the present invention is high in image quality, has no bleeding, has excellent stability over time, and is suitably used for various purposes as a material on which various prints or images are recorded. Can be.
Among the recording media, the liquid absorption property is within a certain range because images with excellent image quality (image density, saturation, beading, color bleed), high gloss, and excellent smear fixability can be recorded. Are preferable. Specifically, commercial printing paper having a coating layer on at least one surface of the support is mentioned, and pure water at a contact time of 100 ms, measured by a dynamic scanning absorptiometer, on the surface having the coating layer is exemplified. Is 2 mL / m ² or more and 35 mL / m ² or less, and the amount of pure water transferred to the printing paper at a contact time of 400 ms is 3 mL / m ² or more and 40 mL / m ² or less. Printing paper is preferred. If the transfer amount of pure water is too small, beading (a phenomenon in which adjacent dots are attracted to make the image appear lumpy) and color bleed (bleeding between colors) are likely to occur. In some cases, if the transfer amount of pure water is too large, the ink dot diameter after recording becomes smaller than a desired diameter, and the solid image may not be filled.

  The transfer amount of pure water can be measured using a dynamic scanning absorptiometer (K350 series D type, manufactured by Kyowa Seiko Co., Ltd.). The transfer amount at a contact time of 100 ms can be obtained by interpolation from the measured value of the transfer amount at a contact time adjacent to the contact time.

  Commercially available printing paper having a liquid absorbing property within the above-mentioned predetermined range include, for example, POD gloss coat, OK top coat +, OK Kinto +, SA Kinto + (manufactured by Oji Paper Co., Ltd.), Super MI Dal, Aurora Coat, Space DX (manufactured by Nippon Paper Co., Ltd.), α-mat, Mu Coat (manufactured by Hokuetsu Paper), Thunderbird Art, Thunderbird Super Art (manufactured by Chuetsu Pulp Industry), Pearl Coat N (manufactured by Mitsubishi Paper Mills), and the like.

<Recording device and recording method>
The ink of the present invention can be suitably used in various recording apparatuses using an ink jet recording system, for example, a printer, a facsimile apparatus, a copying apparatus, a combined printer / fax / copier machine, and a three-dimensional printing apparatus.
In the present invention, a recording device and a recording method are a device capable of discharging ink, various processing liquids, and the like to a recording medium, and a method of performing recording using the device. The recording medium means a medium to which ink and various processing liquids can be temporarily attached.
This recording apparatus can include not only a head portion for discharging ink, but also means for feeding, transporting, and discharging a recording medium, and other devices such as a pre-processing device and a post-processing device. .
The recording device and the recording method may include a heating unit used in the heating step and a drying unit used in the drying step. The heating means and the drying means include, for example, means for heating and drying the printing surface or the back surface of the recording medium. The heating means and the drying means are not particularly limited, and for example, a warm air heater or an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording apparatus and the recording method are not limited to those in which a significant image such as a character or a graphic is visualized by ink. For example, those that form a pattern such as a geometric pattern and the like that form a three-dimensional image are also included.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise limited.
Furthermore, this recording apparatus can use not only a desktop type but also a wide recording apparatus that can print on an A0 size recording medium, or a continuous paper wound in a roll shape as a recording medium. It also includes a simple continuous printer.
An example of the recording apparatus will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective explanatory view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanism section 420 is provided inside an exterior 401 of the image forming apparatus 400. Each ink storage section 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is packaged with, for example, an aluminum laminate film. It is formed by a member. The ink storage unit 411 is stored in a storage container case 414 made of, for example, plastics. Thus, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided behind the opening when the cover 401c of the apparatus main body is opened. The main tank 410 is detachably mounted on the cartridge holder 404. Thus, the ink discharge ports 413 of the main tank 410 and the discharge heads 434 for the respective colors communicate with each other via the supply tubes 436 for the respective colors, and the ink can be discharged from the discharge heads 434 to the recording medium.

The recording apparatus can include not only a portion for discharging ink but also a device called a pre-processing device or a post-processing device.
As one mode of the pre-processing device and the post-processing device, the pre-processing device and the post-processing device include a pre-processing liquid and a post-processing liquid as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y). There is a mode in which a liquid storage unit and a liquid discharge head are added, and a pretreatment liquid and a post-treatment liquid are discharged by an inkjet recording method.
As another embodiment of the pre-processing device and the post-processing device, there is a mode in which a pre-processing device and a post-processing device other than the ink jet recording method, for example, by a blade coating method, a roll coating method, and a spray coating method are provided.

<Recorded>
The ink record of the present invention has an image formed on a recording medium using the ink of the present invention.
A recorded matter can be obtained by recording using an inkjet recording apparatus and an inkjet recording method.

The use of the ink of the present invention is not particularly limited and can be appropriately selected according to the purpose. For example, the ink can be applied to printed matter, paints, coating materials, base materials, and the like. Furthermore, it can be used not only to form two-dimensional characters and images using ink, but also as a material for three-dimensional modeling for forming a three-dimensional three-dimensional image (three-dimensional object).
As a three-dimensional modeling device for modeling a three-dimensional molded object, a known device can be used, and is not particularly limited. For example, a device including an ink storage unit, a supply unit, a discharge unit, a drying unit, and the like is used. be able to. The three-dimensional object includes a three-dimensional object obtained by, for example, over-coating ink. Further, a molded product obtained by processing a structure obtained by applying ink on a base material such as a recording medium is also included. The molded product is, for example, a recording material or a structure formed in a sheet shape or a film shape, which is subjected to a forming process such as a heat drawing or a punching process. It is suitably used for molding after decorating the surface, such as a meter of an electronic device or a camera or a panel of an operation unit.

  Further, image forming, recording, printing, printing and the like in the terms of the present invention are all synonyms.

  A recording medium, a medium, and a printed material are all synonyms.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the examples, “parts” and “%” are “parts by mass” and “% by mass” unless otherwise specified.

<Quinacridone derivative mixture>
A 200 mL four-necked flask cooled in an ice water bath was charged with 50 parts of chlorosulfonic acid, and C.I. I. Pigment Red 122 (Red No. 81, manufactured by Dainichi Seika) was added little by little over 5 minutes at a temperature of 10 to 15 ° C. After further stirring at 80 ° C. for 3 hours and returning to room temperature, the reaction solution was added to 600 parts of ice water with stirring to precipitate a sulfonate. Next, the mixture was separated by filtration, washed with 300 parts of 0.1% hydrochloric acid, and further with 300 parts of ion-exchanged water to obtain a red intermediate wet cake. 150 mL of water was added to this wet cake, and the mixture was cooled to 4 ° C. in an ice water bath with stirring. To this, 10.75 g of diethylamine was added dropwise over 5 minutes, and the mixture was further stirred at 70 ° C. for 3 hours. After cooling to room temperature, 15.6 g of concentrated hydrochloric acid was added with stirring, and the precipitated red precipitate was collected by filtration. This wet cake is stirred and filtered and washed with ion-exchanged water, and heated and dried under reduced pressure at 60 ° C. for 2 days to obtain a quinacridone derivative mixture of maroon brown powder, the following formulas (1-1) and (1-2) 2.67 g of a mixture were obtained.

<Copolymer>
62.0 parts (525 mmol) of 1,6-hexanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 700 mL of methylene chloride, and 20.7 parts (262 mmol) of pyridine was added. A solution of 50.0 parts (262 mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) in 100 mL of methylene chloride was added dropwise to this solution with stirring over 2 hours, and then stirred at room temperature for 6 hours. did. After washing the obtained reaction solution with water, the organic phase was isolated, dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio: 98/2) as an eluent to obtain 52.5 parts of 2-naphthoic acid-2-hydroxyethyl ester. .
Next, 42.1 parts (155 mmol) of 2-naphthoic acid-2-hydroxyethyl ester was dissolved in 80 mL of dry methyl ethyl ketone, and heated to 60 ° C. To this solution, a solution of 24.0 parts (155 mmol) of 2-methacryloyloxyethyl isocyanate (Karenz MOI, manufactured by Showa Denko KK) in 20 mL of dry methyl ethyl ketone was added dropwise with stirring over 1 hour. For 12 hours. After cooling to room temperature, the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio: 99/1) as an eluent, and 57.0 parts of a monomer having a structure represented by the following formula (3): I got

  Next, 1.20 parts (16.7 mmol) of acrylic acid (manufactured by Sigma-Aldrich) and 7.12 parts (16.7 mmol) of a monomer having a structure represented by the formula (3) are dissolved in 40 mL of dry methyl ethyl ketone. To prepare a monomer solution. 10% of the monomer solution was added to a 100 mL flask equipped with a condenser, heated to 75 ° C. under a stream of argon, and 0.273 parts of the remaining monomer solution was added to the solution while stirring the solution. A solution in which (1.67 mmol) of 2,2′-azoiso (butyronitrile) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved was added dropwise over 1.5 hours, and the mixture was further stirred at 60 ° C. for 15 hours. After cooling to room temperature, the obtained reaction solution was dropped into hexane. The precipitated copolymer was separated by filtration and dried under reduced pressure to obtain 8.13 parts of a copolymer. The copolymer was obtained by dissolving the obtained copolymer in an aqueous dimethylethanolamine solution so as to neutralize the acid by 100% and adjusting the concentration with ion-exchanged water so that the concentration of the copolymer became 10%. Was. The weight average molecular weight of the obtained copolymer was 21,800.

[Example 1]
<Dispersion 1>
In 81 parts of ion-exchanged water, 3.2 parts of the copolymer and 0.8 parts of dimethylaminoethanol were added and dissolved, and the compound represented by the formula (1-1) and the compound represented by the formula (1-2) were dissolved. 1.0 part of <quinacridone derivative mixture>, which is a mixture of the compounds represented, and 14.0 parts of a quinacridone pigment (a mixed crystal pigment of CI Pigment Red 202 and Pigment Violet 19, Cinquasia Magenta D4500J manufactured by BASF). Pre-dispersion was performed for 10 minutes using an ultrasonic homogenizer. This was put into an ultra-spec mill UAM015 (manufactured by Kotobuki Kogyo Co., Ltd.) using 0.05 mm zirconia beads, subjected to a dispersion treatment for 1 hour, and the obtained dispersion was filtered through a 1 μm filter to obtain a pigment. A dispersion 1 having a concentration of 14% was obtained.

<Ink 1>
-Dispersion 1 ... 36.0 parts-3-ethyl-3-hydroxymethyloxetane ... 1.0 parts-3-methyl-1,3-butanediol ... 19.0 parts-1,2 -Propanediol ... 10.0 parts-2-ethyl-1,3-hexanediol ... 2.0 parts-Polyoxyethylene polyoxypropylene alkyl ether ... 1.0 part (Emulgen LS-106, Kao Corporation)
・ 2-Amino-2-ethyl-1,3-propanediol ・ ・ ・ 0.5 part ・ Preservative / antifungal agent ・ ・ ・ 0.1 part (Proxel LV, manufactured by Arch Chemicals Japan)
・ Ion-exchanged water: 30.4 parts The above-mentioned components other than the dispersion 1 were dissolved in ion-exchanged water to prepare a vehicle, and then mixed with the dispersion 1 and filtered through a filter having an average pore diameter of 1 μm to form an ink. 1 was obtained.

[Example 2]
In ink 1 of Example 1, 1.0 part of 3-ethyl-3-hydroxymethyloxetane was changed to 2.0 parts, and 19.0 parts of 3-methyl-1,3-butanediol was changed to 18.0 parts. Ink 2 was obtained using the same formulation and method as in Example 1 except for the above.

[Example 3]
In ink 1 of Example 1, 1.0 part of 3-ethyl-3-hydroxymethyloxetane was changed to 5.0 parts, and 19.0 parts of 3-methyl-1,3-butanediol was changed to 15.0 parts. Ink 3 was obtained using the same formulation and method as in Example 1 except for the above.

[Example 4]
Ink 3 of Example 3, except that 5.0 parts of 3-ethyl-3-hydroxymethyloxetane was changed to 5.0 parts of tripropylene glycol monomethyl ether, using the same formulation and method as in Example 3. 4 was obtained.

[Example 5]
Ink 3 of Example 3 was prepared by using the same formulation and method as in Example 3 except that 5.0 parts of 3-ethyl-3-hydroxymethyloxetane was changed to 5.0 parts of methyltriglycol. Obtained.

[Example 6]
Ink 3 was prepared in the same manner as in Example 3 except that 5.0 parts of 3-ethyl-3-hydroxymethyloxetane was changed to 5.0 parts of isopropylidene glycerol in Ink 3 of Example 3. Obtained.

[Example 7]
Ink 3 of Example 3, the same formulation as that of Example 3 except that 5.0 parts of 3-ethyl-3-hydroxymethyloxetane were changed to 5.0 parts of N, N-dimethyl-β-butoxypropionamide. Ink 7 was obtained using the method described above.

Example 8
<Dispersion 2>
14.0 parts of quinacridone pigment (CI Pigment Red 202 and Pigment Violet 19, a mixed crystal pigment of BASF Cinquasia Magenta D4500J) in Dispersion 1 of Example 1 was used as a quinacridone pigment (CI Pigment Red 122, Dispersion 2 was obtained by using the same formulation and method as Dispersion 1, except that 14.0 parts of Red No. 81 (Dainichi Seika) was used.
<Ink 8>
Ink 8 was obtained using the same formulation and method as Ink 3 of Example 3, except that Dispersion 1 in Ink 3 of Example 3 was changed to Dispersion 2.

[Example 9]
<Dispersion 3>
14.0 parts of a quinacridone pigment (CI Pigment Red 202 and Pigment Violet 19, a mixed crystal pigment of CI Pigment Violet 19, Cinquasia Magenta D4500J manufactured by BASF) in Dispersion 1 of Example 1 was used as a quinacridone pigment (CI Pigment Violet 19, Dispersion 3 was obtained using the same formulation and method as Dispersion 1 except that the amount was changed to 14.0 parts (Ink Jet MAGENTA E5B, Clariant Japan).
<Ink 9>
Ink 9 was obtained using the same formulation and method as ink 3 of example 3 except that dispersion 1 in ink 3 of example 3 was changed to dispersion 3.

[Example 10]
<Dispersion 4>
14.0 parts of a quinacridone pigment (CI Pigment Red 122 and Pigment Violet 19, a mixed crystal pigment of CI Pigment Violet 19, BASF Cinquasia Magenta D4500J) in Dispersion 1 of Example 1 was added to a quinacridone pigment (CI Pigment Red 122). Pigment Violet 19, Dispersion 4 was obtained using the same formulation and method as Dispersion 1, except that 14.0 parts of FASTGEN SUPER Magenta RE-05 (manufactured by DIC) were used.
<Ink 10>
Ink 10 was obtained using the same formulation and method as ink 3 of example 3, except that dispersion 1 in ink 3 of example 3 was changed to dispersion 4.

[Example 11]
<Dispersion 5>
14.0 parts of a quinacridone pigment (a mixed crystal pigment of CI Pigment Red 202 and Pigment Violet 19, Cinquasia Magenta D4500J manufactured by BASF) in Dispersion 1 of Example 1 was used as an azo pigment (CI Pigment Red 184, Dispersion 5 was obtained using the same formulation and method as Dispersion 1, except that 14.0 parts of Naphtol Carmine 6B) manufactured by Cappelle Pigment NV were used.
<Ink 11>
Ink 11 was obtained using the same formulation and method as ink 3 of example 3 except that dispersion 1 in ink 3 of example 3 was changed to dispersion 5.

[Example 12]
<Dispersion 6>
14.0 parts of a quinacridone pigment (a mixed crystal pigment of CI Pigment Red 202 and Pigment Violet 19, Cinquasia Magenta D4500J manufactured by BASF) in Dispersion 1 of Example 1 was used as an azo pigment (CI Pigment Red 150, Dispersion 6 was obtained using the same formulation and method as Dispersion 1 except that the pigment was changed to 14.0 parts of Pigment Red 150 (manufactured by Fuji Dye).
<Ink 12>
Ink 12 was obtained using the same formulation and method as Ink 3 of Example 3, except that Dispersion 1 in Ink 3 of Example 3 was changed to Dispersion 6.

Example 13
<Ink 13>
-Dispersion 1 ... 36.0 parts-3-ethyl-3-hydroxymethyloxetane ... 5.0 parts-3-methyl-1,3-butanediol ... 10.0 parts-1,2 -Propanediol ... 10.0 parts-2-ethyl-1,3-hexanediol ... 2.0 parts-Polyoxyethylene polyoxypropylene alkyl ether ... 1.0 part (Emulgen LS-106, Kao Corporation)
・ Urethane resin emulsion 12.5 parts (Takelac W-6110, manufactured by Mitsui Chemicals, Inc., 32.0% aqueous dispersion)
・ 2-Amino-2-ethyl-1,3-propanediol ・ ・ ・ 0.5 part ・ Preservative / antifungal agent ・ ・ ・ 0.1 part (Proxel LV, manufactured by Arch Chemicals Japan)
22.9 parts of ion-exchanged water The above-mentioned components other than the dispersion 1 are dissolved in ion-exchanged water to prepare a vehicle, and then mixed with the dispersion 1 and filtered through a filter having an average pore diameter of 1 μm to form an ink. 13 was obtained.

[Example 14]
<Ink 14>
-Dispersion 1 ... 36.0 parts-3-ethyl-3-hydroxymethyloxetane ... 5.0 parts-3-methyl-1,3-butanediol ... 10.0 parts-1,2 -Propanediol ... 10.0 parts-2-ethyl-1,3-hexanediol ... 2.0 parts-Polyoxyethylene polyoxypropylene alkyl ether ... 1.0 part (Emulgen LS-106, Kao Corporation)
-Acrylic resin emulsion ... 10.0 parts (NANOCLYL-S KPX, 40.0% aqueous dispersion manufactured by Toyochem Co., Ltd.)-2-amino-2-ethyl-1,3-propanediol ... 5 parts-Antiseptic / antifungal agent 0.1 parts (Proxel LV, manufactured by Arch Chemicals Japan)
-Ion-exchanged water ... 25.4 parts After dissolving the above-mentioned components other than the dispersion 1 in ion-exchanged water to prepare a vehicle, the vehicle is mixed with the dispersion 1, and the mixture is filtered through a filter having an average pore diameter of 1 µm to form an ink. 14 was obtained.

[Example 15]
In ink 3 of Example 3, except that 1.0 part of polyethylene wax (AQUACER531, manufactured by BYK, 45.0% aqueous dispersion) was added, and ion-exchanged water was changed from 30.4 parts to 29.4 parts. Using the same formulation and method as in Example 3, ink 15 was obtained.

[Example 16]
Ink 3 of Example 3, except that 1.0 part of the polyether-modified siloxane compound represented by the above formula (2-2) was added, and ion-exchanged water was changed from 30.4 parts to 29.4 parts. Ink 16 was obtained using the same formulation and method as in Example 3.

[Example 17]
In the ink 1 of Example 1, 1.0 part of 3-ethyl-3-hydroxymethyloxetane was changed to 7.8 parts, and 19.0 parts of 3-methyl-1,3-butanediol was changed to 12.2 parts. Ink 17 was obtained using the same formulation and method as in Example 1 except for the above.

[Example 18]
In the ink 1 of Example 1, 1.0 part of 3-ethyl-3-hydroxymethyloxetane was changed to 8.5 parts, and 19.0 parts of 3-methyl-1,3-butanediol was changed to 11.5 parts. An ink 18 was obtained using the same formulation and method as in Example 1 except for the above.

[Example 19]
In the ink 1 of Example 1, 1.0 part of 3-ethyl-3-hydroxymethyloxetane was changed to 9.8 parts, and 19.0 parts of 3-methyl-1,3-butanediol was changed to 10.2 parts. An ink 19 was obtained using the same formulation and method as in Example 1 except for the above.

[Comparative Example 1]
In Ink 3 of Example 3, 5.0 parts of 3-ethyl-3-hydroxymethyloxetane was changed to 12.0 parts, and 15.0 parts of 3-methyl-1,3-butanediol was changed to 8.0 parts. An ink 20 was obtained using the same formulation and method as in Example 3 except for the above.

[Comparative Example 2]
Ink 3 was obtained using the same formulation and method as in Example 3 except that 5.0 parts of 3-ethyl-3-hydroxymethyloxetane was changed to 5.0 parts of 2-pyrrolidone in Ink 3 of Example 3. Was.

[Comparative Example 3]
Ink 3 was obtained using the same formulation and method as in Example 3 except that 5.0 parts of 3-ethyl-3-hydroxymethyloxetane was changed to 5.0 parts of glycerin in Ink 3 of Example 3.

[Comparative Example 4]
<Dispersion 7>
In Dispersion 1 of Example 1, 1.0 part of a <quinacridone derivative mixture> which is a mixture of the compound represented by the formula (1-1) and the compound represented by the formula (1-2) was not added, Quinacridone pigment (mixed crystal pigment of CI Pigment Red 202 and Pigment Violet 19, Cinquasia Magenta D4500J manufactured by BASF) The same formulation and method as in Dispersion 1 except that 14.0 parts was changed to 15.0 parts. Was used to obtain Dispersion 7.
<Ink 23>
Ink 23 was obtained using the same formulation and method as in Example 3 except that Dispersion 1 was changed to Dispersion 7 in Ink 3 of Example 3.

なお、粘度の測定には、粘度計（ＲＥ８０Ｌ、東機産業社製）を使用し、５０回転又は１００回転で２５℃における粘度を測定した。評価結果を表３に示す。
［評価基準］
Ａ：粘度の変化率が±５％以内
Ｂ：粘度の変化率が±５％を超え、±１０％以内
Ｃ：粘度の変化率が±１０％を超え、±３０％以内
Ｄ：粘度の変化率が±３０％を超える（ゲル化して評価不能） <Ink storage stability>
Each ink was filled in an ink cartridge and stored at 70 ° C. for 14 days, and the rate of change of the viscosity after storage with respect to the viscosity before storage was determined from the following formula, and evaluated according to the following criteria.

The viscosity was measured at 25 ° C. at 50 or 100 rotations using a viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.). Table 3 shows the evaluation results.
[Evaluation criteria]
A: Change rate of viscosity is within ± 5% B: Change rate of viscosity exceeds ± 5%, within ± 10% C: Change rate of viscosity exceeds ± 10%, within ± 30% D: Change of viscosity The rate exceeds ± 30% (can not be evaluated due to gelation)

<Ink ejection device>
The inks prepared in Examples and Comparative Examples were set in a commercially available inkjet printer (manufactured by Ricoh, IPSiO GX-e5500), and an operation of printing 1,000 sheets of a print chart with a print area of 5% was performed. After a pause of 24 hours from the end of printing, the following <Ejection stability>, <Saturation>, <Beading>, and <Dryability> were evaluated. The evaluation criteria are shown below. The results are shown in Table 3.

<Discharge stability>
Using the above-described ink ejection device, the droplets were ejected from all the nozzles for one hour.
After 1 hour, a nozzle check pattern is printed on glossy paper for inkjet (Painted Photographic Finish Value, manufactured by FUJIFILM Corporation), and the number of discharge nozzles from which ink has been discharged for all 384 nozzles is confirmed. Evaluation was made according to the following criteria. Table 3 shows the results.
[Evaluation criteria]
A: The number of ejection nozzles is 384 (all nozzles are ejected)
B: The number of discharge nozzles is 368 or more (a level at which there is no problem in actual use)
C: Number of discharge nozzles is 192 or more and less than 368 D: Number of discharge nozzles is less than 192

<Saturation>
A 5 cm × 5 cm solid image was formed on a recording medium (OK top coat + US basis weight 104.7 g / m ² (manufactured by Oji Paper)) with a pixel density of 1200 dpi × 1200 dpi so that the internal temperature was 100 ° C. The printing section was dried for 30 seconds in the set thermostat. Using a reflection-type color spectrophotometer (manufactured by X-Rite), the value of L * a * b * was measured, and the C ^* value was calculated from the measured values of a * and b *. Based on the evaluation. Note that ranks A and B are allowable ranges.
〔Evaluation criteria〕
A: C ^* is 75 or more B: C ^* is 70 or more and less than 75 C: C ^* is 65 or more and less than 70 D: C ^* is less than 65

<Beading>
The beading of a 5 cm × 5 cm solid image formed using the same method as the <Saturation> evaluation was visually confirmed, and evaluated according to the following criteria.
〔Evaluation criteria〕
A: None (not visible from a distance of 15 cm)
B: Very slight
(It is visible from a distance of 15 cm, but not visible from a distance of 50 cm.)
C: Slightly present
(Visible from a distance of 50 cm, but not visible from a distance of 1 m)
D: Violent (visible from a distance of 1m)

<Dryability>
An unprinted paper (4 cm × 4 cm) is superimposed on a 5 cm × 5 cm solid image formed using the same method as the <Saturation> evaluation, and a 2 cm × 2 cm × 0.2 cm thick image is placed thereon. A rubber sheet is placed at the center of the paper, and a weight is placed on the rubber sheet so that the pressure applied to the paper from the rubber sheet is 0.5 kgf / cm ^2. Left for hours. After the standing, the overlapped paper was peeled off, the degree of transfer of the pigment to unprinted paper was visually observed, and the transferability was evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: Transfer of pigment to paper is hardly observed, and sticking between papers is not observed. B: Transfer of pigment to paper is hardly observed, but sticking between papers is observed. C: Slightly sticking to paper. Pigment transfer is seen (transfer of area less than 10% of whole paper)
D: Clear transfer of pigment to paper is observed (transfer of area of 10% or more of the entire paper)

400 Image forming apparatus 401 Exterior of image forming apparatus 401c Cover of apparatus main body 404 Cartridge holder 410 Main tank 410k, 410c, 410m, 410y For each color of black (K), cyan (C), magenta (M), and yellow (Y) Main tank 411 Ink storage section 413 Ink discharge port 414 Storage container case 420 Mechanism section 434 Discharge head 436 Supply tube

JP 2014-065872 A JP 2017-014150A JP-A-2006-145313

Claims (14)

An ink comprising a pigment, a quinacridone derivative represented by the following general formula (1), and a solvent A having an SP value of 9.0 or more and 11.0 or less, wherein the content of the solvent A is less than 10% by mass.

^{(Wherein, R 1, R 2, R} 3 and R ⁴ are a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms, and may be the same or different. Also, R ⁵ and R ⁶ Represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different, and m and n represent integers of 0 to 2, provided that m and n are not 0 simultaneously.   The ink according to claim 1, wherein the content of the solvent A is 2% by mass or more and 8% by mass or less.   The ink according to claim 1, wherein a content of the quinacridone derivative with respect to the pigment is 1% by mass or more and 10% by mass or less.   The ink according to any one of claims 1 to 3, wherein the content of the quinacridone derivative in the ink is 0.01% by mass or more and 1.00% by mass or less based on the total amount of the ink.   The ratio of the content of the quinacridone derivative in the ink to the content of the solvent A (the quinacridone derivative / the solvent A) is 0.045 or more and 0.18 or less. ink.   The solvent according to any one of claims 1 to 5, wherein the solvent A is at least one selected from 3-ethyl-3-hydroxymethyloxetane, isopropylideneglycerol, and N, N-dimethyl-β-butoxypropionamide. ink.   The ink according to any one of claims 1 to 6, wherein the pigment is a quinacridone pigment.   The pigment is C.I. I. Pigment Red 122, C.I. I. Pigment Violet 19, C.I. I. Pigment Red 122 and C.I. I. Pigment Violet 19, or C.I. I. Pigment Red 202 and C.I. I. The ink according to any one of claims 1 to 7, which is a mixed crystal of CI Pigment Violet 19.   The ink according to any one of claims 1 to 8, wherein the ink further contains a resin emulsion, and the resin emulsion is made of an acrylic resin or a urethane resin.   The ink according to any one of claims 1 to 9, wherein the ink further contains a polyethylene wax.   The ink according to any one of claims 1 to 10, wherein the ink further contains a polyether-modified siloxane compound.   An ink container containing the ink according to any one of claims 1 to 11 in a container.   An ink jet recording apparatus comprising: the ink container according to claim 12; and an ejection unit configured to eject ink supplied from the ink container.   A recording method comprising an ink applying step of applying the ink according to claim 1 to a recording medium.

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