JP2015113447A - Inkjet recording ink, ink storing container, inkjet recording apparatus, record production method, and record - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording ink which provides high image density and low print-through density and has excellent pigment dispersion stability.SOLUTION: An inkjet recording ink contains water, a water soluble solvent, a pigment, and a copolymer that is obtained by copolymerizing an addition polymerizable monomer which is to form a structural unit represented by the general formula (1) in the figure, diacetone acrylamide, and 1-vinylnaphthalene or 2-vinylnaphthalene.

Description

  The present invention relates to an ink for ink jet recording, an ink storage container using the ink, an ink jet recording apparatus, a method for producing a recorded matter, and a recorded matter.

In recent years, as an image forming method, since the process is simple and full color can be easily obtained as compared with other recording methods, there is an advantage that a high-resolution image can be obtained even with an apparatus having a simple configuration. The method has become widespread. The ink jet recording system is a system in which a small amount of ink is ejected by an ink jet recording apparatus and is deposited on a recording medium such as paper, and its application has been expanded to personal and industrial printers and printing.
As the ink, a water-based ink containing a water-soluble dye as a colorant is mainly used. However, the dye ink has a defect that it is inferior in weather resistance and water resistance. Therefore, in recent years, research on pigment inks using pigments instead of water-soluble dyes has been advanced. However, the pigment ink is inferior in color development, ink ejection stability, and storage stability as compared with dye ink. In addition, with the improvement in image quality improvement technology of OA printers, even when pigment ink is used for plain paper, an image density equivalent to that of dye ink is required. However, when plain paper is used as a recording medium, the pigment ink has a problem that the pigment concentration on the paper surface is lowered by penetrating into the paper and the image density is lowered. Further, in order to increase the drying speed of the ink adhering to the recording medium as a measure for high-speed printing, means for increasing the drying speed by adding a penetrant to the ink and allowing water to penetrate into the recording medium is taken. In addition to water, the permeability of the pigment into the recording medium is increased, and the image density is further lowered.

Various methods have been proposed for improving the image density.
For example, Patent Document 1 proposes an ink-jet ink composition containing a liquid vehicle, a colorant, and a polymer having at least one functional group having a specific calcium index value. In this proposal, 4-methacrylamide-1-hydroxybutane-1,1-diphosphonic acid is shown as a monomer constituting the polymer, and when the colorant comes into contact with the paper, the diphosphonic acid group of the polymer and the paper It is said that the density of the printed image can be improved by making it unstable with the Ca salt in the inside.
Patent Document 2 discloses an ink used for recording on paper containing a water-soluble polyvalent metal salt. This ink has (a) a pigment, (b) no surface activity, a molecular weight of 150 to 10,000, and a functional group having phosphoric acid as a basic skeleton in its molecular structure and a basic phosphonic acid. The content of phosphorus derived from the functional group having a skeleton ((P content / molecular weight) × 100) is selected from a functional group having a basic skeleton of phosphoric acid and a functional group having a basic skeleton of phosphonic acid, which are 1.4 or more And (b) the content of the compound is 1.5% by mass or more and 10.0% by mass or less based on the total mass of the ink.

In Patent Document 1, a polymer is not used as a dispersant and an additive for a pigment dispersion, but is coated with a colorant, and the functional group of the polymer is adjacent to a diphosphonic acid group and a hydroxyl group. There is a problem that the dispersion stability of the ink is low because hydrogen bonds between the diphosphonic acid group and the hydroxyl group are likely to occur. Further, 4-methacrylamide-1-hydroxybutane-1,1-diphosphonic acid is exemplified as a monomer constituting the polymer, but there is no example of the monomer of the general formula (5) used in the present invention. There is no illustration of a copolymer using 5), general formula (6) and structural formula (7) or structural formula (8), and the effect on improving the dispersion stability of the pigment is not described.
On the other hand, Patent Document 2 exemplifies monomers of structural formula (7) and structural formula (8) in the present invention as monomers for the copolymer, but the general formula (5) in the present invention was used. There is no exemplification of the copolymer, and there is no description on the effect of improving the image density, the effect of reducing the strikethrough and the improvement of the dispersion stability of the pigment in plain paper having a low content of the water-soluble polyvalent metal salt.
Therefore, the present invention solves the problems of the prior art, provides a high image density even for plain paper, reduces the back-through of the image, and further stabilizes the dispersion of the pigment in the pigment dispersion and ink. An object of the present invention is to provide an ink for ink jet recording having good properties.

上記式中、Ｒ１は、水素原子又はメチル基を表す。Ｍは、水素原子、アルカリ金属又は有機アンモニウムを表す。

＜一般式（２）＞

上記式中、Ｒ２は、水素原子又はメチル基を表す。

＜構造式（３）＞

＜構造式（４）＞

As a result of intensive studies, the present inventors have used a copolymer having a phosphonic acid group and a specific structural unit as a component of an ink for ink jet recording (hereinafter sometimes referred to as ink), so that the ink is a plain paper. By agglomerating on the paper surface and staying on the paper surface, a high image density on plain paper can be obtained, image back-through is reduced, and further pigment dispersion and dispersion of the pigment in the ink Has been found to be stable, leading to the present invention.
That is, the above problem is solved by the following invention 1).
1) In an inkjet recording ink containing at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphonic acid group, the copolymer containing the phosphonic acid group is represented by at least the following general formula (1). An inkjet recording ink comprising: a structural unit represented by the following general formula (2); and a structural unit represented by the following structural formula (3) or structural formula (4):
<General formula (1)>

In the above formula, R1 represents a hydrogen atom or a methyl group. M represents a hydrogen atom, an alkali metal, or organic ammonium.

<General formula (2)>

In the above formula, R2 represents a hydrogen atom or a methyl group.

<Structural formula (3)>

<Structural formula (4)>

  According to the present invention, a high image density can be obtained even with respect to plain paper, the image see-through is reduced, and the pigment dispersion and the dispersion stability of the pigment in the ink are good. Can be provided.

FIG. 3 is a schematic plan view for explaining an example of the ink container of the present invention. FIG. 2 is a schematic plan view including a case (exterior) of the ink container of the present invention shown in FIG. 1. 1 is a perspective view showing an example of a serial type ink jet recording apparatus of the present invention. FIG. 4 is a partially enlarged sectional view of the ink jet recording apparatus shown in FIG. 3. FIG. 4 is another partially enlarged cross-sectional view of the ink jet recording apparatus shown in FIG. 3.

上記式中、Ｒ３は、水素原子又はメチル基を表す。

＜一般式（６）＞

上記式中、Ｒ４は、水素原子又はメチル基を表す。

＜構造式（７）＞

＜構造式（８）＞

３） 前記共重合体における一般式（１）の構造単位の含有率が、１０〜６０質量％であることを特徴とする１）に記載のインクジェット記録用インク。
４） 前記共重合体の固形分１０質量％水溶液又は固形分１０質量％水分散液の２５℃における粘度が、１．５〜３０．０ｍＰａ・ｓであることを特徴とする１）〜３）のいずれかに記載のインクジェット記録用インク。
５） 前記共重合体が、顔料分散体の顔料の分散剤として含有されていることを特徴とする１）〜４）のいずれかに記載のインクジェット記録用インク。
６） 前記顔料分散体における顔料と共重合体の質量比率が、顔料／共重合体＝１００／１０〜１００／１００であることを特徴とする５）に記載のインクジェット記録用インク。
７） 前記一般式（１）のＭが水素原子、カリウム原子又はナトリウム原子であることを特徴とする１）〜６）のいずれかに記載のインクジェット記録用インク。
８） 前記一般式（１）のＭの総数に対する水素原子の割合が４０％以下であることを特徴とする１）〜７）のいずれかに記載のインクジェット記録用インク。
９） 前記水溶性溶剤として、少なくともグリセリンを含むことを特徴とする１）〜８）のいずれかに記載のインクジェット記録用インク。
１０） インク収容部に１）〜９）のいずれかに記載のインクが収容されていることを特徴とするインク収納容器。
１１） １０）に記載のインク収納容器を備えたことを特徴とするインクジェット記録装置。
１２） １）〜９）のいずれかに記載のインクをインクジェットヘッドから吐出させて記録媒体に記録を行う工程を有することを特徴とする記録物の製造方法。
１３） １）〜９）のいずれかに記載のインクを用いて記録媒体に情報又は画像が記録されていることを特徴とする記録物。 Hereinafter, the present invention 1) will be described in detail, but the following 2) to 13) are also included in the embodiment of the present invention, and these will be described together.
2) In an inkjet recording ink containing at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphonic acid group, the copolymer containing the phosphonic acid group is represented by at least the following general formula (5). Inkjet characterized by being synthesized using a monomer represented by the following general formula (6) and a monomer represented by the following structural formula (7) or structural formula (8) as starting materials Recording ink.
<General formula (5)>

In the above formula, R3 represents a hydrogen atom or a methyl group.

<General formula (6)>

In the above formula, R4 represents a hydrogen atom or a methyl group.

<Structural formula (7)>

<Structural formula (8)>

3) The ink for inkjet recording according to 1), wherein the content of the structural unit of the general formula (1) in the copolymer is 10 to 60% by mass.
4) The viscosity at 25 ° C. of the 10% by weight solid content aqueous solution or 10% by weight solid content aqueous dispersion of the copolymer is 1.5 to 30.0 mPa · s 1) to 3) An ink for ink jet recording according to any one of the above.
5) The ink for inkjet recording according to any one of 1) to 4), wherein the copolymer is contained as a dispersant for a pigment of a pigment dispersion.
6) The ink for inkjet recording according to 5), wherein a mass ratio of the pigment and the copolymer in the pigment dispersion is pigment / copolymer = 100/10 to 100/100.
7) The ink for ink jet recording according to any one of 1) to 6), wherein M in the general formula (1) is a hydrogen atom, a potassium atom or a sodium atom.
8) The ink for ink jet recording according to any one of 1) to 7), wherein a ratio of hydrogen atoms to the total number of M in the general formula (1) is 40% or less.
9) The ink for inkjet recording according to any one of 1) to 8), wherein the water-soluble solvent contains at least glycerin.
10) An ink storage container in which the ink according to any one of 1) to 9) is stored in an ink storage unit.
11) An ink jet recording apparatus comprising the ink container described in 10).
12) A method for producing a recorded matter comprising a step of recording on a recording medium by discharging the ink according to any one of 1) to 9) from an inkjet head.
13) A recorded matter in which information or an image is recorded on a recording medium using the ink according to any one of 1) to 9).

The phosphonic acid group of the general formula (1) exhibits hydrophilicity, but has a characteristic of reacting with polyvalent metal ions such as calcium ion, magnesium ion, and aluminum ion to be hydrophobized. Therefore, when an ink using a copolymer containing a phosphonic acid group as a pigment dispersant is used for a recording medium containing a water-soluble polyvalent metal salt, the pigment dispersant adsorbed on the pigment is eluted from the recording medium. Aggregation of the pigment occurs because it reacts with the polyvalent metal ion to be hydrophobized. As a result, the penetration of the pigment into the paper can be suppressed, and a high image density can be obtained. Further, the back-through where the image can be seen through from the back side of the paper surface can be reduced.
However, in PPC plain paper that contains almost no water-soluble polyvalent metal salt, the amount of polyvalent metal ions eluted from the recording medium is small. It was insufficient.

As a method for solving the above problems, a method using a copolymer containing a phosphonic acid group which is a hydrophilic functional group, or increasing the proportion of the hydrophobic structural unit of the pigment dispersant to enhance the adsorption of the dispersant and the pigment. A method is conceivable. However, if phosphonic acid groups are introduced into the copolymer, the interaction between the phosphonic acid groups becomes stronger, or the dispersibility of the pigment may decrease or the viscosity may increase when the pigment dispersion and the water-soluble solvent are mixed. found. It has also been found that increasing the proportion of hydrophobic structural units decreases the dispersion stability of the pigment in the pigment dispersion and the ink and increases the viscosity.
As a result of further investigation, the above problem can be solved by combining the structural unit of the general formula (2) and the structural unit of the structural formula (3) or the structural formula (4) in addition to the structural unit of the general formula (1). It was found that a high image density can be obtained even on plain paper having a low content of water-soluble polyvalent metal salt or containing only a hardly soluble metal salt. Further, it has been found that the dispersion stability of the pigment in the pigment dispersion and the ink can be secured.

The effect of each structure of General formula (1), General formula (2), Structural formula (3), and Structural formula (4) is as the following [1]-[3].
[1] The introduction of the general formula (1) increases the reactivity of the copolymer with metal ions, and when the ink containing the copolymer lands on the paper, the pigment is easily aggregated. As a result, a very high image density was obtained and the show-through was reduced.
[2] The structure of the general formula (2) has high affinity for a water-soluble solvent, and an increase in viscosity when a pigment dispersion using a copolymer and a water-soluble solvent are mixed to form an ink is suppressed. A low-viscosity ink advantageous for ejection can be obtained.
[3] By introducing the structural formula (3) or the structural formula (4), the adsorptive power of the copolymer to the pigment is improved, and the dispersibility stability of the pigment when used as a dispersant is improved. Further, when the copolymer reacts with metal ions, the pigment is easily aggregated, and as a result, the image density is improved.

<Copolymer>
The copolymer used in the present invention is represented by the structural unit represented by the general formula (1), the structural unit represented by the general formula (2), and the structural formula (3) or the structural formula (4). And other structural units as necessary.
Examples of the alkali metal of M in the general formula (1) include lithium, sodium, and potassium. Examples of organic ammonium include alkylamines such as mono, di or trimethylamine, mono, di or triethylamine; ethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, dimethylethanolamine, monopropanolamine, dipropanol Alcohol amines such as amine, tripropanolamine, isopropanolamine, trishydroxymethylaminomethane, 2-amino-2-ethyl-1,3-propanediol (AEPD); choline, morpholine, N-methylmonoformin, N -Cyclic amines such as methyl-2-pyrrolidone and 2-pyrrolidone.
In particular, sodium or potassium is desirable in terms of both image density and storage stability.
The ratio of hydrogen atoms to the total number of M in the general formula (1) constituting the copolymer is preferably 40% or less. When the ratio exceeds 40%, the reactivity between the copolymer and calcium ions or other polyvalent metal ions decreases, and the effect of improving the image density decreases.

上記式中、Ｍは、水素原子、アルカリ金属、又は有機アンモニウムを表す。
The structural unit represented by the general formula (1) is preferably a structural unit represented by the following general formula (9).
<General formula (9)>

In said formula, M represents a hydrogen atom, an alkali metal, or organic ammonium.

In addition to the structural unit represented by the general formula (1), general formula (2), structural formula (3), or structural formula (4), the copolymer further has a structure derived from other polymerizable monomer. Units can be included.
There is no restriction | limiting in particular as said other polymerizable monomer, According to the objective, it can select suitably, For example, a polymerizable hydrophobic monomer, a polymerizable hydrophilic monomer, etc. are mentioned.

Examples of the polymerizable hydrophobic monomer include unsaturated ethylene monomers having an aromatic ring such as styrene, α-methylstyrene, 4-t-butylstyrene, 4-chloromethylstyrene; methyl (meth) acrylate, (Meth) ethyl acrylate, (n-butyl) (meth) acrylate, dimethyl maleate, dimethyl itaconate, dimethyl fumarate, lauryl (meth) acrylate (C12), tridecyl (meth) acrylate (C13), ( Tetradecyl (meth) acrylate (C14), pentadecyl (meth) acrylate (C15), hexadecyl (meth) acrylate (C16), heptadecyl (meth) acrylate (C17), nonadecyl (meth) acrylate (C19), Eicosyl acrylate (C20), helicosyl (meth) acrylate ( 21), alkyl (meth) acrylates such as docosyl (meth) acrylate (C22); 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, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene , Unsaturated ethylene monomers having an alkyl group such as 1-octadecene, 1-nonadecene, 1-eicocene and 1-docosene.
These may be used individually by 1 type and may use 2 or more types together.

Examples of the polymerizable hydrophilic monomer include (meth) acrylic acid or a salt thereof, maleic acid or a salt thereof, monomethyl maleate, itaconic acid, monomethyl itaconic acid, fumaric acid, 4-styrenesulfonic acid, 2-acrylamide. Anionic unsaturated ethylene monomers such as -2-methylpropanesulfonic 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-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, acrylamide, N, N-dimethyl Le acrylamide, N-t-butylacrylamide, N- octyl acrylamide, nonionic ethylenically unsaturated monomers such as N-t-octyl acrylamide, and the like.
These may be used individually by 1 type and may use 2 or more types together.

The mass ratio of the structural unit represented by the general formula (1) is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 to 60% by mass of the copolymer mass, and 20 to 40%. More preferred is mass%. Within the preferred range, it is advantageous in that a high image density can be obtained when used in ink, and dispersion stability and storage stability are good.
Moreover, as for the structural ratio of the structural unit represented by the said General formula (2), 10-35 mass% of a copolymer mass is preferable. When it is 10% by mass or more, the viscosity of the dispersion and the ink becomes low, and when it is 35% by mass or less, the effect of improving the image density is clearly exhibited.
Moreover, as for the structural ratio of the structural unit represented by the said Structural formula (3) or Structural formula (4), 20-70 mass% of copolymer mass is preferable. Within the preferred range, it is advantageous in that a high image density can be obtained when used in ink, and dispersion stability and storage stability are good.
The copolymer can be widely used in various fields, but can be suitably used as a pigment dispersant, a pigment concentration improver, a binder resin for pigment, a viscosity modifier, and the like in ink.

<Method for producing copolymer>
The copolymer contains at least the monomer represented by the general formula (5), the general formula (6), the structural formula (7), or the structural formula (8), and, if necessary, the other polymerizable monomer. After the polymerization, the obtained copolymer can be obtained by a production method including a step of neutralizing with an alkali metal base or an organic amine base. More specifically, a solvent and each of the above monomers are placed in a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, and copolymerized at 50 ° C. to 150 ° C. using a polymerization initiator under nitrogen gas reflux. Then, neutralization treatment may be performed.
Instead of neutralization after copolymerization, the monomer represented by the general formula (5) may be copolymerized after previously neutralizing with an alkali metal base or organic amine base.

＜構造式（１１）＞

Examples of the compound represented by the general formula (5) include 1-methacryloxyethane-1,1-diphosphonic acid represented by the following structural formula (10) in which R3 is a methyl group, and R3 is a hydrogen atom. Specific examples thereof include 1-acryloxyethane-1,1-diphosphonic acid represented by the following structural formula (11). These compounds can be synthesized, for example, by the method described in JP-A-58-2222095.
<Structural formula (10)>

<Structural formula (11)>

As a method for synthesizing the copolymer, a method using a radical polymerization initiator is preferable because the polymerization operation and the molecular weight are easily adjusted, and a solution polymerization method in which polymerization is performed in an organic solvent is more preferable.
There is no restriction | limiting in particular as said radical polymerization initiator, According to the objective, it can select suitably. Examples thereof include peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyesters, cyano azobisisobutyronitriles, azobis (2-methylbutyronitrile), Examples thereof include azobis (2,2′-isovaleronitrile) and non-cyano dimethyl-2,2′-azobisisobutyrate. Among these, organic peroxides and azo compounds are preferable, and azo compounds are particularly preferable from the viewpoint of easy control of molecular weight and low decomposition temperature.
There is no restriction | limiting in particular in content of the said polymerization initiator, Although it can select suitably according to the objective, 1-10 mass% is preferable with respect to the total mass of a polymerizable monomer.

  There is no restriction | limiting in particular in the solvent at the time of performing radical polymerization by a solution polymerization method, According to the objective, it can select suitably, For example, ketone solvents, such as methanol, ethanol, acetone, methyl ethyl ketone, methyl isobutyl ketone; And acetate solvent such as butyl acetate; aromatic hydrocarbon solvents such as benzene, toluene and xylene; isopropanol, ethanol, cyclohexane, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoamide, and the like. Among these, ketone solvents, acetate solvents, and alcohol solvents are preferable.

In order to adjust the molecular weight of the copolymer, an appropriate amount of a chain transfer agent may be added.
Examples of the chain transfer agent include mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol, thiophenol, dodecyl mercaptan, 1-dodecanethiol, thioglycerol, and the like.
There is no restriction | limiting in particular in polymerization temperature, Although it can select suitably according to the objective, 50 to 150 degreeC is preferable and 50 to 100 degreeC is more preferable. There is no restriction | limiting in particular in superposition | polymerization time, Although it can select suitably according to the objective, 3-48 hours are preferable.

Although the obtained copolymer is neutralized, it may be copolymerized using a monomer represented by the general formula (5) that has been previously neutralized as described above. Furthermore, it is possible to neutralize the pigment and copolymer in a mixed state in the ink production process.
By the neutralization treatment, part or all of the phosphonic acid groups of the copolymer are neutralized.
The neutralization rate of the phosphonic acid group in the copolymer after neutralization treatment referred to in the present invention is a value determined by the following method, and the proton in the copolymer is actually a metal ion or an organic ammonium ion. It is different from the rate of replacement.
The monomer represented by the general formula (5) is referred to as “monomer 1”.
Neutralization rate X (%) = (number of moles of added base x base cation valence)
÷ (number of moles of monomer 1 contained in copolymer × 4) × 100
Number of moles of base added = amount of base added Yg ÷ molecular weight of base Number of moles of monomer 1 contained in copolymer
= Charge amount of monomer 1 Zg / Molecular weight of monomer 1 Accordingly, the amount of base necessary to obtain the neutralization rate X% is expressed by the following equation.
Addition amount of base Yg = neutralization rate X (%) × (preparation amount of monomer 1 Zg × 4)
X base molecular weight / (base cation valence x 100 x monomer 1 molecular weight)

The viscosity at 25 ° C. of the 10% by weight aqueous solution or 10% by weight aqueous dispersion of the copolymer is preferably 1.5 to 30.0 mPa · s. If it is 1.5 mPa · s or more, the reactivity between the metal ion eluted from the paper and the pigment dispersant is further improved, and the effect of improving the image density becomes remarkable. Moreover, the dispersion stability of a pigment improves that it is 30.0 mPa * s or less, and the storage stability of a pigment dispersion improves more.
The weight average molecular weight of the copolymer can be controlled to some extent by the polymerization temperature, the polymerization initiator amount, and the monomer concentration during the reaction. With respect to 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 obtained when polymerized at a low temperature for a long time.

(Inkjet recording ink)
The ink of the present invention contains water, a water-soluble organic solvent, and the copolymer, and further contains other components as necessary.
The content of the copolymer in the ink is preferably 0.5 to 10.0% by mass, more preferably 1.0 to 5.0% by mass as the solid content. The effect of improving the image density clearly appears from 0.5% by mass, and by setting it to 10.0% by mass or less, it is possible to suppress the viscosity to a range suitable for ejecting ink from the head.

The copolymer may be used as an additive, but if it is used as a pigment dispersant, a higher image density and an effect of reducing show-through can be obtained. When used as a pigment dispersant, in addition to the structural unit represented by the general formula (1), general formula (2), structural formula (3), or structural formula (4), other hydrophilic polymerizability Monomer-derived structural units can be included. As the hydrophilic polymerizable monomer, those described above can be used.
There is no restriction | limiting in particular when using the said copolymer as a pigment dispersant, Although it can select suitably according to the objective, 10-100 mass parts is preferable with respect to 100 mass parts of pigments. If the content is within this range, a high image density can be obtained. Moreover, you may use together the dispersing agent mentioned later in the range which does not impair the effect as a dispersing agent of a copolymer.

The ink of the present invention is preferably used for paper having an amount of Ca ions eluted from the paper of 1.0 × 10 ^{−4 to} 5.0 × 10 ⁻⁴ [g / g]. When the Ca ion amount is 1.0 × 10 ⁻⁴ [g / g] or more, the effect of improving the image density by reaction aggregation with the pigment dispersant is improved, and the ink penetration into the paper is not hindered. This improves the drying property, and also improves the scratch resistance and marker resistance.
The amount of Ca ions eluted from the paper is calculated by the following method.
That is, the paper is cut into 2.5 cm (± 0.5 cm) × 3.5 cm (± 0.5 cm) square pieces and filtered with a 0.8 μm cellulose acetate filter (manufactured by Advantech) using high-purity water. Remove foreign substances such as paper dust. Next, the paper piece is immersed in high purity water, and Ca ions contained in the immersion liquid are quantified by an ICP emission spectroscopic analyzer. The Ca ion concentration [ppm] obtained here is multiplied by 200 g, which is the weight of high-purity water, and is further divided by 16 g, which is the weight of the immersed paper. The amount of Ca ions eluted from the paper [g / g ] Is calculated.
For example, the amount of Ca ions of MyPaper (manufactured by Ricoh) is 4.3 × 10 ⁻⁴ [g / g], and the amount of Ca ions of Xerox 4024 (manufactured by Fuji Xerox) is 1.7 × 10 ⁻⁴ [g / g]. g].

(water)
Examples of water used in the present invention include pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water.
The water content is preferably 20 to 60% by mass of the total ink.

(Water-soluble solvent)
The water-soluble solvent is used for improving the ejection stability of the ink by providing a moisturizing effect. The content is preferably 10 to 50% by mass of the whole ink. When the content is 10% by mass or more, it is difficult for the ink to evaporate water, the ink water evaporation in the ink supply system in the ink jet recording apparatus is suppressed, and ink clogging is less likely to occur. Further, when the content is 50% by mass or less, the ink viscosity can be suppressed low and a high image density can be obtained even if the content of solids such as pigments and resins is large.

Examples of the water-soluble solvent include, but are not limited to, the following.
Ethylene glycol, diethylene glycol, 1,3-butanediol, 3-methyl-1,3-butyl glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerin, 1 , 2,6-hexanetriol, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,2,4-butanetriol, 1,2,3-butane Polyhydric alcohols such as triol and petriol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene Polyhydric alcohol alkyl ethers such as recall monomethyl ether and propylene glycol monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; 2-pyrrolidone, N-methyl-2-pyrrolidone, Nitrogen-containing heterocyclic compounds such as N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone; amides such as formamide, N-methylformamide, N, N-dimethylformamide Amines such as monoethanolamine, diethanolamine and triethylamine; sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol; propylene carbonate, ethylene carbonate and the like.
These water-soluble solvents can be used alone or in admixture of two or more.
Among these, when 1,3-butanediol, diethylene glycol, 2,2,4-trimethyl-1,3-pentanediol, triethylene glycol and / or glycerin are included, it is excellent in preventing discharge failure due to moisture evaporation. Effect.

The water-soluble solvent used in the present invention includes a penetrant. The penetrant preferably contains either a polyol compound having 8 to 11 carbon atoms or a glycol ether compound having 8 to 11 carbon atoms.
The penetrant can be referred to as a “non-wetting medium”. These non-wetting agent penetrants preferably have a solubility of between 0.2 and 5.0% by weight in water at 25 ° C. Among these, 2-ethyl-1,3-hexanediol [solubility: 4.2% by mass (25 ° C.)], 2,2,4-trimethyl-1,3-pentanediol [solubility: 2.0% by mass] (25 ° C.)] is particularly preferred.
Examples of other polyol compounds include 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-1,2-diol And aliphatic diols such as

Other penetrants that can be used in combination are not particularly limited as long as they can be dissolved in ink and adjusted to desired physical properties, and can be appropriately selected according to the purpose. Examples thereof include alkyls and aryls of polyhydric alcohols such as diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, and tetraethylene glycol chlorophenyl ether. And ethers, lower alcohols such as ethanol, and the like.
The content of the penetrant in the ink is preferably 0.1 to 4.0% by mass. If the content is less than 0.1% by mass, quick drying may not be obtained and a blurred image may be obtained. On the other hand, if it exceeds 4.0% by mass, the dispersion stability of the pigment is impaired, the nozzle is easily clogged, the permeability to the recording medium (recording medium) becomes higher than necessary, and the image density. May be reduced or show through.

(Pigment)
The content of the pigment used in the present invention in the ink is preferably 0.1 to 20.0% by mass. The volume average particle diameter (D50) of the pigment is preferably 150 nm or less. The volume average particle diameter (D50) of the pigment was measured by a dynamic light scattering method using a Microtrac UPA manufactured by Nikkiso Co., Ltd. in an environment of 23 ° C. and 55% RH.
There is no restriction | limiting in particular as a pigment, According to the objective, it can select suitably, Any of an inorganic pigment and an organic pigment may be sufficient. These may be used alone or in combination of two or more.
Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, metal powder, and carbon black. Among these, carbon black is preferable. In addition, as said carbon black, what was manufactured by well-known methods, such as a contact method, a furnace method, and a thermal method, is mentioned, for example.

Examples of the organic pigment include azo pigments, azomethine pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are more preferable.
Examples of the azo pigments include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of the polycyclic pigment include a phthalocyanine pigment, a perylene pigment, a perinone pigment, an anthraquinone pigment, a quinacridone pigment, a dioxazine pigment, an indigo pigment, a thioindigo pigment, an isoindolinone pigment, a quinofullerone pigment, and a rhodamine B lake pigment. . Examples of the dye chelate include basic dye chelate and acid dye chelate.

Examples of black materials include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, and metals such as copper and iron (CI pigment black 11). And metal oxides such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).
The carbon black is a carbon black produced by a furnace method or a channel method, a primary particle size of 15 to 40 nm, a specific surface area by a BET method of 50 to 300 m ² / g, and a DBP oil absorption of 40 to 150 ml / Those having 100 g, a volatile content of 0.5 to 10%, and a pH value of 2 to 9 are preferred.

  Examples of commercially available carbon black include No. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all manufactured by Mitsubishi Chemical Corporation); Raven700, 5750, 5250, 5000, 3500, 1255 (all manufactured by Colombia); Regal400R, 330R, 660R, Mogu L, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot Corporation); Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A, and 4 (all manufactured by Degussa).

  There is no restriction | limiting in particular as a pigment which can be used for the said color, and can be used for yellow ink, According to the objective, it can select suitably. Examples thereof include C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 180, and the like.

  There is no restriction | limiting in particular as a pigment which can be used for the said magenta ink for the said color, According to the objective, it can select suitably. Examples thereof include C.I. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, pigment violet 19, and the like.

  There is no restriction | limiting in particular as a pigment which can be used for the said cyan for cyan, and it can select suitably according to the objective. Examples thereof include C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Bat Blue 60 and the like.

The pigment used in the present invention may be newly produced for the present invention.
In addition, when pigment yellow 74 is used as the yellow pigment, pigment red 122, pigment bio red 19 as the magenta pigment, and pigment blue 15: 3 as the cyan pigment is used, an ink having excellent color tone and light fastness and balanced can be obtained. be able to.
Furthermore, in the present invention, it is possible to use a surfactant such as a dispersant or a pigment coated or encapsulated with a resin, but the copolymer is used as a dispersant. Is more preferable. Moreover, you may use together the pigment mentioned above in the range which does not impair an effect.

(Other ingredients)
The other components used in the ink of the present invention are not particularly limited and can be appropriately selected as necessary. For example, a dispersant, a pH adjuster, a water-dispersible resin, an antiseptic / antifungal agent, a chelating reagent, Examples thereof include a rust inhibitor, an antioxidant, an ultraviolet absorber, an oxygen absorber, and a light stabilizer.

(Dispersant)
As the dispersant, a copolymer containing a phosphonic acid group of the present invention is preferable, but various surfactants and polymers such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant are used. Also included are types of dispersants. These may be used alone or in combination of two or more.
Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurate, polyoxyalkyl ether sulfates. Salt, polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester salt, lauryl alcohol sulfate ester salt, alkylphenol type phosphate ester, naphthalenesulfonate formalin condensate, alkyl type phosphate ester, alkylallylsulfone hydrochloride, diethyl Examples include sulfosuccinate, diethylhexyl sulfosuccinate, and dioctyl sulfosuccinate.

Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.
Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, imidazoline. Derivatives and the like.
Examples of nonionic surfactants include the following.
Ether surface activity such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyallyl alkyl ether Agent;
Polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate Ester surfactants such as
2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octane-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol Acetylene glycol surfactants such as.

(PH adjuster)
The pH adjuster is not particularly limited as long as it can adjust the pH to 8.5 to 11 (preferably 9 to 11) without adversely affecting the ink to be prepared, and is appropriately selected according to the purpose. be able to. Examples thereof include alcohol amines, alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like. When the pH is less than 8.5 or more than 11, the amount of the ink-jet head or the ink supply unit that melts out increases, which may cause problems such as ink deterioration, leakage, and ejection failure. When it is less than 8.5, the ink pH may decrease during storage of the ink, and the polymer fine particles may aggregate due to an increase in the particle diameter.
The pH can be measured by, for example, a pH meter (HM-30R, manufactured by TOA-DKK).
Examples of the alcohol amines include diethanolamine, triethanolamine, and 2-amino-2-ethyl-1,3-propanediol. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the ammonium hydroxide include ammonium hydroxide and quaternary ammonium hydroxide. Examples of the phosphonium hydroxide include quaternary phosphonium hydroxide. Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

(Water dispersible resin)
As the water-dispersible resin, those having excellent film-forming properties (image forming properties) and having high water repellency, high water resistance, and high weather resistance have high water resistance and high image density (high color developability). Useful for image recording.
Specific examples thereof include condensation-type synthetic resins, addition-type synthetic resins, and natural polymer compounds.
Examples of the condensed synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, poly (meth) acrylic resin, acrylic-silicone resin, and fluorine-based resin. Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like. Examples of the natural polymer compound include celluloses, rosins, and natural rubber.
Among these, polyurethane resin fine particles, acrylic-silicone resin fine particles, and fluorine-based resin fine particles are particularly preferable.

The volume average particle diameter (D50) of the water-dispersible resin is related to the viscosity of the dispersion, and for the same composition, the viscosity at the same solid content increases as the particle diameter decreases. The volume average particle diameter (D50) of the water-dispersible resin is preferably 50 nm or more so that the ink does not have an excessively high viscosity. Further, when the particle size is several tens of μm, it becomes larger than the nozzle opening of the ink jet head and cannot be used. If particles having a large particle diameter are present in the ink even if smaller than the nozzle opening, the ejection stability is deteriorated. Therefore, the volume average particle diameter (D50) is more preferably 200 nm or less in order not to inhibit the ink ejection stability.
The volume average particle size (D50) of the water-dispersible resin is measured by a dynamic light scattering method using a Microtrac UPA manufactured by Nikkiso Co., Ltd. in an environment of 23 ° C. and 55% RH.
The water-dispersible resin preferably has a function of fixing the water-dispersed pigment on the paper surface, and forms a film at room temperature to improve the fixability of the pigment. Therefore, it is preferable that the minimum film-forming temperature (MFT) of the water-dispersible resin is 30 ° C. or less.
In addition, when the glass transition temperature of the water dispersible resin is less than −40 ° C., the viscosity of the resin film becomes strong and the printed matter is tacked. Therefore, the water dispersible resin has a glass transition temperature of −40 ° C. or higher. It is preferable.
The content of the water-dispersible resin in the ink is preferably 1 to 15% by mass, more preferably 2 to 7% by mass in terms of solid content.

(Antiseptic and antifungal agent)
Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, sodium pentachlorophenol, and the like.
(Chelating reagent)
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.
(Rust inhibitor)
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

(Antioxidant)
Examples of the antioxidant include phenolic antioxidants (including hindered phenolic antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.
(UV 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 ultraviolet absorber.

(Inkjet recording ink manufacturing method)
The ink of the present invention is obtained by dispersing or dissolving water, a water-soluble solvent, a pigment, a copolymer containing a phosphonic acid group, and other components as necessary in an aqueous medium, and further stirring and mixing as necessary. To manufacture.
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc., and stirring and mixing are performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser, or the like. be able to.

The physical properties of the ink of the present invention are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. is preferably 3 to 20 mPa · s. By setting the viscosity to 3 mPa · s or more, the effect of improving the printing density and character quality can be obtained. On the other hand, by suppressing the viscosity to 20 mPa · s or less, dischargeability can be ensured.
The viscosity can be measured at 25 ° C. using, for example, a viscometer (RL-550, manufactured by Toki Sangyo Co., Ltd.).
The surface tension of the ink is preferably 40 mN / m or less at 25 ° C. When the surface tension exceeds 40 mN / m, leveling of the ink on the recording medium is difficult to occur and the drying time may be prolonged.

(Ink container)
The ink container of the present invention includes an ink container that stores the ink of the present invention, and further includes other members appropriately selected as necessary.
The shape, structure, size, and material of the container are not particularly limited and may be appropriately selected depending on the intended purpose. It is mentioned in.
An example of the ink container of the present invention is shown in FIGS. FIG. 1 is a schematic plan view of the ink container, and FIG. 2 is a schematic plan view including a case (exterior) of the ink container of FIG.
As shown in FIG. 1, the ink container 200 is filled with ink from the ink inlet 242 into the ink container 241 and exhausted, and then the ink inlet 242 is closed by fusion. In use, the needle of the apparatus main body is pierced into the ink discharge port 243 made of a rubber member and supplied to the apparatus. The ink container 241 is formed of a packaging member such as an aluminum laminate film that does not have air permeability. As shown in FIG. 2, the ink storage unit 241 is normally stored in a plastic container case 244 and is detachably mounted on various ink jet recording apparatuses.

(Inkjet recording apparatus and inkjet recording method)
The ink jet recording apparatus of the present invention records information or an image on the recording medium using the ink of the present invention with an ink jet head. This recording apparatus has at least ink flying means for ejecting ink, and further has other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.
The ink flying means is a means for forming an image by applying a stimulus to the ink of the present invention and causing it to fly. The ink flying means is not particularly limited, and examples thereof include various nozzles for ejecting ink.
The stimulus can be generated by, for example, the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, such as heat (temperature), pressure, vibration, light, etc. Can be mentioned. These may be used individually by 1 type and may use 2 or more types together. Of these, heat and pressure are preferred. Examples of the stimulus generating means include a superheating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, and a light. Specifically, a piezoelectric actuator such as a piezoelectric element such as a piezoelectric element, a thermal actuator that uses a phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a shape that uses a metal phase change due to a temperature change Memory alloy actuators, electrostatic actuators using electrostatic force, and the like can be mentioned.

There is no particular limitation on the mode of the ink flight, and it varies depending on the type of the stimulus.
For example, when the stimulus is “heat”, thermal energy corresponding to a recording signal is applied to the ink in the recording head using, for example, a thermal head, and bubbles are generated in the ink by the thermal energy. Examples include a method of ejecting and ejecting the ink as droplets from the nozzle holes of the recording head by the pressure of the bubbles. When the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element is bent, For example, a method of reducing the volume and ejecting and ejecting the ink as droplets from the nozzle holes of the recording head can be used.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

Here, an outline of the ink jet recording apparatus of the present invention used in the examples and an ink jet recording method using the recording apparatus will be described.
FIG. 3 is a perspective view showing an example of the serial type ink jet recording apparatus of the present invention. The recording apparatus includes an apparatus main body 101, a paper feed tray 102 for loading paper loaded in the apparatus main body 101, and paper discharge for stocking paper on which an image is recorded (formed) mounted on the apparatus main body 101. The tray 103 has an ink container loading portion 104 that protrudes forward from the front surface 112 and is lower than the upper cover 111 on one end of the front surface 112 of the apparatus main body 101. An operation unit 105 such as operation keys and a display is arranged on the upper surface of the ink container loading unit 104. The ink storage container loading unit 104 has a front cover 115 that can be opened and closed for detaching the ink storage container 200.
In the apparatus main body 101, as shown in FIGS. 4 and 5 (partially enlarged sectional view of the recording apparatus in FIG. 3), a guide rod 131 which is a guide member horizontally mounted on left and right side plates, not shown, The carriage 132 holds the carriage 133 slidably in the main scanning direction, and moves and scans in the direction of the arrow as shown in FIG. 5 by the main scanning motor.

The carriage 133 is provided with a plurality of ink ejection heads 134 including four inkjet recording heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The outlets are arranged so as to cross the main scanning direction, and the ink droplet ejection direction is directed downward.
Examples of the ink jet recording head constituting the recording head 134 include a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a metal phase caused by a temperature change. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for ejecting ink can be used. In addition, the carriage 133 is equipped with a sub tank 135 for each color for supplying ink of each color to the recording head 134. The sub tank 135 is supplied with ink from the ink container 200 of the present invention loaded in the ink container loading unit 104 via an ink supply tube (not shown) and is replenished.

On the other hand, as a paper feeding unit for feeding the paper 142 stacked on the paper stacking unit (pressure plate) 141 of the paper feeding tray 102, a half-moon roller (feeding) that separates and feeds the paper 142 from the paper stacking unit 141 one by one. A separation pad 144 made of a material having a large coefficient of friction is provided facing the paper roller 143) and the paper feed roller 143, and the separation pad 144 is urged toward the paper feed roller 143 side.
As a transport unit for transporting the paper 142 fed from the paper feed unit below the recording head 134, a transport belt 151 for transporting the paper 142 by electrostatic adsorption and a guide 145 from the paper feed unit. The counter roller 152 for transporting the paper 142 fed via the transport belt 151 with the transport belt 151 and the paper 142 fed substantially vertically upward are changed by approximately 90 ° so as to follow the transport belt 151. For this purpose, a conveyance guide 153 and a tip pressure roller 155 urged toward the conveyance belt 151 by a pressing member 154 are provided.

In addition, a charging roller 156 that is a charging unit for charging the surface of the conveyance belt 151 is provided. The conveyance belt 151 is an endless belt, is stretched between the conveyance roller 157 and the tension roller 158, and can circulate in the belt conveyance direction. The transport belt 151 includes, for example, a surface layer serving as a sheet adsorbing surface formed of a resin material (for example, a copolymer of tetrafluoroethylene and ethylene (ETFE)) having a thickness of about 40 μm that is not subjected to resistance control, and the surface layer. And a back layer (medium resistance layer, grounding layer) that is controlled by carbon with the same material. On the back side of the conveyance belt 151, a guide member 161 is arranged corresponding to a printing area by the recording head 134.
Note that, as a paper discharge unit for discharging the paper 142 recorded by the recording head 134, a separation claw 171 for separating the paper 142 from the conveyance belt 151, a paper discharge roller 172, and a paper discharge roller 173 are provided. The paper discharge tray 103 is disposed below the paper discharge roller 172.
A double-sided paper feeding unit 181 is detachably mounted on the back surface of the apparatus main body 101.
The double-sided paper feeding unit 181 takes in the paper 142 returned by the reverse rotation of the transport belt 151, reverses it, and feeds it again between the counter roller 152 and the transport belt 151. A manual paper feed unit 182 is provided on the upper surface of the duplex paper feed unit 181.

In this ink jet recording apparatus, the paper 142 is separated and fed one by one from the paper feed unit, and the paper 142 fed substantially vertically upward is guided by the guide 145 and between the transport belt 151 and the counter roller 152. It is sandwiched and conveyed. Further, the leading end is guided by the conveying guide 153 and pressed against the conveying belt 151 by the leading end pressure roller 155, and the conveying direction is changed by approximately 90 °. At this time, the conveyance belt 157 is charged by the charging roller 156, and the sheet 142 is conveyed by being electrostatically attracted to the conveyance belt 151. Therefore, by driving the recording head 134 according to the image signal while moving the carriage 133, ink droplets are ejected onto the stopped paper 142 to record one line, and after the paper 142 is conveyed by a predetermined amount, Record the next line.
Upon receiving a recording end signal or a signal that the trailing edge of the sheet 142 has reached the recording area, the recording operation is terminated, and the sheet 142 is discharged onto the discharge tray 103. When a near-end remaining amount of ink in the sub tank 135 is detected, a required amount of ink is supplied from the ink container 200 to the sub tank 135.

In this ink jet recording apparatus, when the ink in the ink container 200 is used up, the casing of the ink container 200 can be disassembled and only the ink container inside can be replaced. In addition, the ink container 200 can supply ink stably even when the ink container 200 is placed vertically and has a front loading configuration. Accordingly, even when the upper portion of the apparatus main body 101 is closed and installed, for example, when stored in a rack, or when an object is placed on the upper surface of the apparatus main body 101, the ink container 200 can be easily exchanged.
In addition, although it demonstrated in the example applied to the serial type (shuttle type) inkjet recording device which a carriage scans, it can apply similarly to the line type inkjet recording device provided with the line type head.
The ink jet recording apparatus of the present invention can be applied to various types of recording by the ink jet recording method, and is particularly preferably applied to, for example, an ink jet recording printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like. Can do.

(Recorded matter and method for producing recorded matter)
The recorded matter of the present invention is a recorded matter in which information or an image is recorded on a recording medium (recording medium) using the ink of the present invention. The recorded matter of the present invention can be produced by a step of recording on a recording medium by discharging ink from an inkjet head.
The recording medium is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include plain paper, printing coated paper, glossy paper, special paper, cloth, film, and OHP sheet. . These may be used individually by 1 type and may use 2 or more types together. Among these, any of plain paper and printing coated paper is preferable. The plain paper is advantageous in that it is inexpensive. Further, the coated paper for printing is advantageous in that it provides a smooth glossy image at a relatively low cost compared to glossy paper. However, although the drying property is poor and it is generally difficult to use for inkjet, the drying property is improved by the ink of the present invention.
The recorded matter of the present invention has high image quality, no bleeding, excellent temporal stability, and can be suitably used for various purposes as a material on which various prints or images are recorded.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited at all by these Examples. In the examples, “parts” and “%” represent “parts by mass” and “mass%” unless otherwise specified.

(Measurement of copolymer viscosity)
About each synthesize | combined copolymer, the viscosity of the 10 mass% aqueous solution or 10 mass% aqueous dispersion liquid is 25 degreeC using a rotational viscometer (viscosity meter RE80L, cone plate type, the Toki Sangyo company make). It was measured. Specifically, 1.1 mL of each copolymer was sampled and placed in a viscometer sample cup, which was attached to the viscometer body and allowed to stand for 1 minute, and then the viscometer rotor was rotated, Read the value. The rotation speed at the time of viscosity measurement was adjusted so that the torque was constant within a range of 40 to 80%.

<Synthesis of copolymer>
(Synthesis Example 1)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 30.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 10.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 60.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 10 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 1 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous solution of the obtained copolymer 1 at 25 ° C. was 1.9 mPa · s.

(Synthesis Example 2)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 30.0 parts, diacetone acrylamide [monomer wherein R4 is a hydrogen atom in the general formula (6)] 5.0 parts, 2-vinylnaphthalene [monomer represented by the structural formula (8) ] 65.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 10 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 2 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of 10% aqueous solution of the obtained copolymer 2 at 25 ° C. was 2.2 mPa · s.

(Synthesis Example 3)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group Monomer] 30.0 parts, diacetone methacrylamide [monomer in which R4 is a methyl group in the general formula (6)] 10.0 parts, 1-vinylnaphthalene [represented by the structural formula (7) Monomer] 60.0 parts and a polymerization initiator (azubisisobutyronitrile) 4.0 parts were charged and heated to 65 ° C. Next, after carrying out a polymerization reaction for 10 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 3 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous solution of the obtained copolymer 3 at 25 ° C. was 3.3 mPa · s.

(Synthesis Example 4)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol) and 1-acryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a hydrogen atom 30.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 10.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 60.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 10 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 4 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of 10% aqueous solution of the obtained copolymer 4 at 25 ° C. was 2.0 mPa · s.

(Synthesis Example 5)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 15.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 50.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 75 ° C. Next, after carrying out a polymerization reaction for 3 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, followed by drying, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 5 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% aqueous solution of the obtained copolymer 5 at 25 ° C. was 1.1 mPa · s.

(Synthesis Example 6)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group Which is a monomer] 5.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 60.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 5 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, followed by drying, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 6 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous solution of the obtained copolymer 6 at 25 ° C. was 1.6 mPa · s.

(Synthesis Example 7)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 15.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 50.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 5 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, followed by drying, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 7 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% aqueous solution of the obtained copolymer 7 at 25 ° C. was 1.8 mPa · s.

(Synthesis Example 8)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 55.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 10.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 75 ° C. Next, after carrying out a polymerization reaction for 3 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, followed by drying, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 8 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous solution of the obtained copolymer 8 at 25 ° C. was 1.2 mPa · s.

(Synthesis Example 9)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 65.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 20.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 15.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 5 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, followed by drying, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 9 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% aqueous solution of the obtained copolymer 9 at 25 ° C. was 1.7 mPa · s.

(Synthesis Example 10)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 55.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 25.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) 20.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 5 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, followed by drying, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 10 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous solution of the obtained copolymer 10 at 25 ° C. was 1.6 mPa · s.

(Synthesis Example 11)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 55.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 10.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 50 ° C. Next, after carrying out a polymerization reaction for 48 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 11 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous dispersion at 25 ° C. of the obtained copolymer 11 was 30.1 mPa · s.

(Synthesis Example 12)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 65.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 20.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 15.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 50 ° C. Next, after carrying out a polymerization reaction under a nitrogen stream for 24 hours, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 12 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous solution of the obtained copolymer 12 at 25 ° C. was 25.0 mPa · s.

(Synthesis Example 13)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 55.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 10.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 50 ° C. Next, after carrying out a polymerization reaction under a nitrogen stream for 24 hours, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 13 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of 10% aqueous solution of the obtained copolymer 13 at 25 ° C. was 28.9 mPa · s.

(Synthesis Example 14)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 15.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 50.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 50 ° C. Next, after carrying out a polymerization reaction for 48 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 14 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous dispersion at 25 ° C. of the obtained copolymer 14 was 30.5 mPa · s.

(Synthesis Example 15)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group Which is a monomer] 5.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 60.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 50 ° C. Next, after carrying out a polymerization reaction under a nitrogen stream for 24 hours, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 15 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous solution of the obtained copolymer 15 at 25 ° C. was 27.7 mPa · s.

(Synthesis Example 16)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 15.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 50.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 50 ° C. Next, after carrying out a polymerization reaction under a nitrogen stream for 24 hours, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 16 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% aqueous solution of the obtained copolymer 16 at 25 ° C. was 29.5 mPa · s.

(Synthesis Example 17)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group Which is a monomer] 5.0 parts, diacetone acrylamide [monomer wherein R4 is a hydrogen atom in the general formula (6)] 35.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 60.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 75 ° C. Next, after carrying out a polymerization reaction for 3 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, followed by drying, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 17 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% aqueous solution of the obtained copolymer 17 at 25 ° C. was 1.3 mPa · s.

(Synthesis Example 18)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 65.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 20.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 15.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 50 ° C. Next, after carrying out a polymerization reaction for 48 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 18 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of the 10% aqueous dispersion at 25 ° C. of the obtained copolymer 18 was 31.0 mPa · s.

(Synthesis Example 19)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 20.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in general formula (6)] 10.0 parts, 1-vinylnaphthalene [monomer represented by structural formula (7) 70.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 10 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, sodium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 19 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of 10% aqueous solution of the obtained copolymer 19 at 25 ° C. was 1.9 mPa · s.

(Synthesis Example 20)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 30.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 10.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 60.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 10 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, lithium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 20 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of 10% aqueous solution of the obtained copolymer 20 at 25 ° C. was 2.0 mPa · s.

(Synthesis Example 21)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 20.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in general formula (6)] 10.0 parts, 1-vinylnaphthalene [monomer represented by structural formula (7) 70.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 10 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, dimethylethanolamine was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 21 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% aqueous solution of the obtained copolymer 21 at 25 ° C. was 2.5 mPa · s.

(Synthesis Example 22)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 30.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 10.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 60.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 10 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 70% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 22 having 70% neutralized phosphonic acid groups was synthesized. The viscosity of 10% aqueous solution of the obtained copolymer 22 at 25 ° C. was 2.6 mPa · s.

(Synthesis Example 23)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 1-methacryloxyethane-1,1-diphosphonic acid [in the general formula (5), R3 represents a methyl group 30.0 parts, diacetone acrylamide [monomer in which R4 is a hydrogen atom in the general formula (6)] 10.0 parts, 1-vinylnaphthalene [monomer represented by the structural formula (7) ] 60.0 parts and 4.0 parts of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction under a nitrogen stream for 24 hours, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 50% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 23 having 50% neutralized phosphonic acid groups was synthesized. The viscosity of 10% aqueous solution of the obtained copolymer 23 at 25 ° C. was 3.0 mPa · s.

(Synthesis Example 24)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of solvent (ethanol), 30.0 parts of methacrylic acid, diacetone acrylamide [in the general formula (6), R4 is a hydrogen atom. Monomer] 10.0 parts, 1-vinylnaphthalene [monomer represented by the above structural formula (7)] 60.0 parts, polymerization initiator (azubisisobutyronitrile) 4.0 parts, charged at 65 ° C. The temperature rose. Next, after carrying out a polymerization reaction for 15 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into acetone to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this manner, a copolymer 24 in which the phosphonic acid group was 100% acid neutralized was synthesized. The viscosity of the 10% aqueous solution of the obtained copolymer 24 at 25 ° C. was 13.2 mPa · s.

(Synthesis Example 25)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts of a solvent (1-methoxy-2-propanol) and Phosmer M (2-methacryloxyethyl acid phosphoate, Unichemical Co.) 18. 0 parts, St (styrene) 30.0 parts, MMA (methyl methacrylate) 20.0 parts, BMA (butyl methacrylate) 18.0 parts, MAA (methacrylic acid) 10.0 parts, polymerization initiator (Azbis) 4.0 parts of isobutyronitrile) was charged, and the temperature was raised to 110 ° C. Next, after carrying out a polymerization reaction for 4 hours under a nitrogen stream, about half of the charged solvent is distilled off from the reaction system, and the mixture is poured into methanol to precipitate a copolymer, which is further dried, A polymer was obtained.
While diluting the obtained copolymer with water, potassium hydroxide was added so that 100% acid neutralization could be achieved, and the concentration was adjusted with water so that the solid concentration was 10%. In this way, a copolymer 25 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% aqueous solution of the obtained copolymer 25 at 25 ° C. was 11.5 mPa · s.

Table 1 shows the properties of the copolymers 1 to 25 synthesized as described above.
The monomer (MAA) in the column of structure 1 of the copolymer 24 is not a monomer of structure 1. Further, the monomers in the columns of the structures 1 to 3 of the copolymer 25 are not the monomers of the structures 1 to 3.

Details of the abbreviations shown in Table 1 and counter ions are as follows.
MEDP: 1-methacryloxyethane-1,1-diphosphonic acid AEDP: 1-acryloxyethane-1,1-diphosphonic acid DAAM: diacetone acrylamide DMAAM: diacetone methacrylamide 1-ViN: 1- Vinyl naphthalene 2-ViN: 2-vinyl naphthalene St: Styrene MAA: Methacrylic acid MMA: Methyl methacrylate BMA: Butyl methacrylate DMEA: Dimethylethanolamine

<Preparation Examples 1-36 of Pigment Dispersion>
Each pigment dispersion was prepared as follows.
(Preparation Example 1): Black pigment dispersion 1
The material of the following prescription was premixed to prepare a mixed slurry. This was circulated and dispersed for 3 minutes at a peripheral speed of 10 m / s and a liquid temperature of 10 ° C. using a disk type media mill (manufactured by Ashizawa Finetech Co., Ltd., DMR type) with 0.05 mm zirconia beads and a filling rate of 55%. Subsequently, coarse particles were centrifuged with a centrifuge (Model 7700, manufactured by Kubota Corporation) to obtain Pigment Dispersion 1 having a pigment concentration of 16%.
・ Carbon black (NIPEX160, manufactured by degussa,
BET specific surface area 150 m ² / g, average primary particle size 20 nm, pH 4.0,
DBP oil absorption 620 g / 100 g) ... 160 parts-Copolymer 1 ... 40 parts-Distilled water ... 800 parts

(Preparation Example 2): Black pigment dispersion 2
A pigment dispersion 2 having a pigment concentration of 16% was obtained in the same manner as in Preparation Example 1, except that the copolymer 1 of Preparation Example 1 was changed from 40 parts to 10 parts and distilled water was changed from 800 parts to 830 parts. It was.

(Preparation Example 3): Black pigment dispersion 3
A pigment dispersion 3 having a pigment concentration of 16% was obtained in the same manner as in Preparation Example 1, except that the copolymer 1 of Preparation Example 1 was changed from 40 parts to 20 parts and distilled water was changed from 800 parts to 820 parts. It was.

(Preparation Example 4): Black pigment dispersion 4
A pigment dispersion 4 having a pigment concentration of 16% is obtained in the same manner as in Preparation Example 1, except that the copolymer 1 of Preparation Example 1 is changed from 40 parts to 160 parts and distilled water is changed from 800 parts to 680 parts. It was.

(Preparation Example 5): Black pigment dispersion 5
A pigment dispersion 5 having a pigment concentration of 16% was obtained in the same manner as in Preparation Example 1, except that the copolymer 1 of Preparation Example 1 was changed from 40 parts to 200 parts and distilled water was changed from 800 parts to 640 parts. It was.

(Preparation Example 6): Black pigment dispersion 6
A pigment was prepared in the same manner as in Preparation Example 1 except that the copolymer 1 of Preparation Example 1 was changed to a polyoxyethylene (POE) (m = 40) -β-naphthyl ether (Takemoto Yushi Co., Ltd.) 10% aqueous solution. A pigment dispersion 6 having a concentration of 16% was obtained.

(Preparation Example 7): Cyan pigment dispersion 1
A pigment dispersion 7 having a pigment concentration of 16% was obtained in the same manner as in Preparation Example 1, except that the carbon black of Preparation Example 1 was changed to Pigment Blue 15: 3 (Dainipei Seika Co., Ltd., Chromofine Blue). .

(Preparation Example 8): Magenta pigment dispersion 1
A pigment dispersion 8 having a pigment concentration of 16% was obtained in the same manner as in Preparation Example 1 except that the carbon black of Preparation Example 1 was changed to Pigment Red 122 (manufactured by Clariant, Toner Magenta EO02).

(Preparation Example 9): Yellow pigment dispersion 1
A pigment dispersion 9 having a pigment concentration of 16% was obtained in the same manner as in Preparation Example 1, except that the carbon black of Preparation Example 1 was changed to Pigment Yellow 74 (Daiichi Seika Chemical Co., Ltd., First Yellow 531).

(Preparation Example 10) to (Preparation Example 33): Black pigment dispersions 8 to 29
Pigment dispersions 10 to 33 having a pigment concentration of 16% were obtained in the same manner as in Preparation Example 1, except that the copolymer 1 of Preparation Example 1 was changed to Copolymer 2 to Copolymer 25.

(Preparation Example 34): Cyan pigment dispersion 2
A pigment is prepared in the same manner as in Preparation Example 1 except that the carbon black of Preparation Example 1 is changed to Pigment Blue 15: 3 (Dainipei Chemical Co., Ltd., Chromofine Blue) and the copolymer 1 is changed to the copolymer 24. A pigment dispersion 34 having a concentration of 16% was obtained.

(Preparation Example 35): Magenta pigment dispersion 2
A pigment concentration of 16% was obtained in the same manner as in Preparation Example 1 except that the carbon black of Preparation Example 1 was changed to Pigment Red 122 (manufactured by Clariant, Toner Magenta EO02) and Copolymer 1 was changed to Copolymer 24. A pigment dispersion 35 was obtained.

(Preparation Example 36): Yellow pigment dispersion 2
A pigment concentration of 16 was obtained in the same manner as in Preparation Example 1 except that the carbon black of Preparation Example 1 was changed to Pigment Yellow 74 (Daiichi Seika Chemicals Co., Ltd., First Yellow 531) and Copolymer 1 was changed to Copolymer 24. % Of pigment dispersion 36 was obtained.

表２−１、表２−２中の[＊]は、ポリオキシエチレン（ＰＯＥ）（ｍ＝４０）−β−ナフチルエーテル１０％水溶液を表す。 The composition of each pigment dispersion obtained in Preparation Examples 1 to 36 is summarized in Tables 2-1 and 2-2. In addition, the numerical value in a table | surface is a mass part.

[*] In Tables 2-1 and 2-2 represents a 10% aqueous solution of polyoxyethylene (POE) (m = 40) -β-naphthyl ether.

[Examples 1 to 33, Comparative Examples 1 to 5]
<Preparation of ink for ink jet recording>
(Example 1)
The materials of the following formulation were stirred for 1 hour and mixed uniformly, and the resulting dispersion was pressure filtered through a polyvinylidene fluoride membrane filter having an average pore size of 5.0 μm to remove coarse particles and dust. 1 ink was produced.
Pigment dispersion 1 (pigment concentration 16%) 50.0 parts Glycerin 10.0 parts 1,3-butanediol 20.0 parts Distilled water 20.0 parts

(Examples 2-33, Comparative Examples 1-5)
Each ink was produced in the same manner as in Example 1 except that the materials shown in the columns of Examples 2 to 33 and Comparative Examples 1 to 5 in Table 3-1 and Table 3-2 were used. In addition, the numerical value in Table 3-1 and Table 3-2 is the mass%.

Various properties of the pigment dispersion and ink were measured and evaluated as follows. The results are summarized in Table 4.

<Evaluation of storage stability of pigment dispersion and ink>
For each of the pigment dispersions 1 to 36 and Examples 1 to 33 and Comparative Examples 1 to 5, the viscosity at 25 ° C. was measured using a viscometer RE80L manufactured by Toki Sangyo Co., Ltd. The rotation speed at the time of viscosity measurement was adjusted so that the torque was constant within a range of 40 to 80%.
As an index of the dispersion stability of the pigment in each pigment dispersion and each ink, the initial viscosity after preparation of the pigment dispersion and the ink was measured and evaluated according to the following criteria.
For storage stability, after measuring the initial viscosity at 25 ° C., each pigment dispersion and each ink were sealed in a polyethylene container, and the viscosity after storage at 70 ° C. for 1 week was measured. Based on the rate of change from the viscosity, the following criteria were used.

[Evaluation criteria for pigment dispersion]
Initial viscosity A: Initial viscosity value is less than 3 mPa · s B: Initial viscosity value is 3 mPa · s or more and less than 10 mPa · s C: Initial viscosity value is 10 mPa · s or more

Storage stability A: Change rate of viscosity after storage based on initial viscosity is less than 5% B: Change rate of viscosity after storage based on initial viscosity is 5% or more and less than 50% C: Initial viscosity The change rate of viscosity after storage based on

[Ink evaluation criteria]
Initial viscosity A: Initial viscosity value is less than 10 mPa · s B: Initial viscosity value is 10 mPa · s or more and less than 20 mPa · s C: Initial viscosity value is 20 mPa · s or more

Storage stability A: Change rate of viscosity after storage based on initial viscosity is less than 5% B: Change rate of viscosity after storage based on initial viscosity is 5% or more and less than 50% C: Initial viscosity The change rate of viscosity after storage based on

Further, the viscosity of the ink when 30% of the water in the ink was evaporated was measured as an index of the dispersion stability of the pigment when the water was evaporated. Specifically, 30 g of ink was put in a 50 mL glass beaker and left in an environment of 50 ° C. to evaporate water. Then, the viscosity η (30%) at 25 ° C. when the mass of the ink was reduced by 30% compared to the initial value was obtained. Also, the initial viscosity η (0%) at 25 ° C. of the ink was measured to obtain η (30%) / η (0%), and evaluated according to the following criteria.
〔Evaluation criteria〕
Viscosity change rate at 30% water evaporation A: η (30%) / η (0%) value is less than 10 B: η (30%) / η (0%) value is 10 or more, 100 Less than C: The value of η (30%) / η (0%) is 100 or more

<Evaluation of printing of each ink>
Using an ink jet printer (IPSiO GXe5500, manufactured by Ricoh), change the drive voltage of the piezo element so that the amount of ink discharged is uniform, and set so that the same amount of ink adheres to the recording material, The following printing evaluation was performed.

<< Image density & showthrough >>
64 point JIS created by Microsoft Word 2003 using each ink
X 0208 (1997), 2223 A chart describing general symbols is printed on My Paper (Ricoh Co., Ltd.), then the symbol part is color-measured by X-Rite 938 (X-Rite Co., Ltd.) and the image density is measured. Evaluated. The print mode was “plain paper-fast” mode with the driver attached to the printer. The image density of each color was evaluated according to the following criteria. In the evaluation, four measurement locations per color were measured once for each chart, and the average value of the four locations was taken as the measurement result for each color. Note that JIS X 0208 (1997), 2223 is a symbol whose outer shape is a regular square and the entire symbol surface is filled with ink.
Further, using X-Rite 938, the image density (OD value) of the symbol part and the OD value of the non-printing part of the paper are measured from the back side measurement of the paper, and the non-printing part of the paper is determined from the OD value of the symbol part. The OD value obtained by subtracting the OD value was evaluated as the back-through concentration according to the same criteria as described above.

[Image density (OD value) evaluation criteria]
A: OD value Black 1.30 or more
Yellow 0.80 or more
Magenta 0.95 or higher
Cyan 1.05 or more B: OD value Black 1.20 or more, less than 1.30
Yellow 0.75 or more, less than 0.80
Magenta 0.85 or more, less than 0.95
Cyan 0.95 or more and less than 1.05 C: OD value Black 1.10 or more and less than 1.20
Yellow 0.70 or more, less than 0.75
Magenta 0.75 or more and less than 0.85
Cyan 0.85 or more, less than 0.95 D: OD value Black less than 1.10
Yellow less than 0.70
Less than magenta 0.75
Cyan less than 0.85

[Evaluation criteria for strikethrough density (OD value)]
A: OD value Black Less than 0.10
Yellow less than 0.08
Magenta less than 0.09
Cyan Less than 0.10 B: OD value Black 0.10 or more, less than 0.20
Yellow 0.08 or more, less than 0.16
Magenta 0.09 or more, less than 0.18
Cyan 0.10 or more and less than 0.20 C: OD value Black 0.20 or more and less than 0.50
Yellow 0.16 or more, less than 0.40
Magenta 0.18 or more, less than 0.40
Cyan 0.20 or more, less than 0.50 D: OD value Black 0.50 or more
Yellow 0.40 or more
Magenta 0.40 or higher
Cyan 0.50 or more

DESCRIPTION OF SYMBOLS 101 Device main body 102 Paper feed tray 103 Paper discharge tray 104 Ink storage container loading part 105 Operation part 111 Upper cover 112 Front surface 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Sub tank 141 Paper mounting part 142 Paper 143 Paper feed Roller 144 Separation pad 145 Guide 151 Conveying belt 152 Counter roller 153 Conveying guide 154 Holding member 155 Tip pressure roller 156 Charging roller 157 Conveying roller 158 Densation roller 161 Guide member 171 Separating claw 172 Discharging roller 173 Discharging roller 181 Double-sided feeding Paper unit 182 Manual paper feed unit 200 Ink container 241 Ink container 242 Ink inlet 243 Ink outlet 244 Case (exterior)

Japanese Patent No. 5001291 JP 2011-122072 A

Claims (13)

In an inkjet recording ink containing at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphonic acid group, the copolymer containing the phosphonic acid group is represented by at least the following general formula (1). An ink for ink jet recording comprising a structural unit, a structural unit represented by the following general formula (2), and a structural unit represented by the following structural formula (3) or (4).
<General formula (1)>

In the above formula, R1 represents a hydrogen atom or a methyl group. M represents a hydrogen atom, an alkali metal, or organic ammonium.

<General formula (2)>

In the above formula, R2 represents a hydrogen atom or a methyl group.

<Structural formula (3)>

<Structural formula (4)>

In the inkjet recording ink containing at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphonic acid group, the copolymer containing the phosphonic acid group is represented by at least the following general formula (5). Inkjet recording characterized by being synthesized using a monomer, a monomer represented by the following general formula (6), and a monomer represented by the following structural formula (7) or structural formula (8) as starting materials For ink.
<General formula (5)>

In the above formula, R3 represents a hydrogen atom or a methyl group.

<General formula (6)>

In the above formula, R4 represents a hydrogen atom or a methyl group.

<Structural formula (7)>

<Structural formula (8)>

  The ink for inkjet recording according to claim 1, wherein the content of the structural unit of the general formula (1) in the copolymer is 10 to 60% by mass.   4. The viscosity at 25 ° C. of a 10 mass% solid content aqueous solution or 10 mass% solid dispersion of the copolymer is 1.5 to 30.0 mPa · s. An ink for ink jet recording according to claim 1.   The ink for inkjet recording according to any one of claims 1 to 4, wherein the copolymer is contained as a dispersant for the pigment of the pigment dispersion.   6. The ink for ink jet recording according to claim 5, wherein a mass ratio of the pigment and the copolymer in the pigment dispersion is pigment / copolymer = 100/10 to 100/100.   The ink for inkjet recording according to any one of claims 1 to 6, wherein M in the general formula (1) is a hydrogen atom, a potassium atom or a sodium atom.   The ink for inkjet recording according to any one of claims 1 to 7, wherein a ratio of hydrogen atoms to a total number of M in the general formula (1) is 40% or less.   The ink for inkjet recording according to any one of claims 1 to 8, wherein the water-soluble solvent contains at least glycerin.   An ink storage container, wherein the ink storage unit stores the ink according to claim 1.   An ink jet recording apparatus comprising the ink container according to claim 10.   A method for producing a recorded matter comprising a step of recording on a recording medium by discharging the ink according to claim 1 from an ink jet head.   A recorded matter in which information or an image is recorded on a recording medium using the ink according to claim 1.

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