JP6146700B2 - INKJET RECORDING INK, INK CONTAINER, INKJET RECORDING DEVICE, RECORDED MATERIAL MANUFACTURING METHOD, AND RECORDED MATERIAL - Google Patents

Description

  The present invention relates to an ink for ink jet recording (hereinafter sometimes simply referred to as “ink”), an ink container, 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 method is a method 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 the application has been expanded to personal and industrial printers and printing.

  Ink jet recording apparatuses mainly use water-based ink using a water-soluble dye as a colorant, but the dye ink has a disadvantage 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 still inferior in color development, ink ejection stability, and storage stability to the dye ink. In addition, with the improvement of image quality improvement technology for OA printers, image density equivalent to that of dye ink is required for pigment ink even when plain paper is used as a recording medium. However, when plain paper is used as a recording medium, the pigment ink has a problem that the pigment density on the paper surface is lowered by penetrating into the paper and the image density is lowered. In order to increase the drying speed of the ink adhering to the recording medium for high-speed printing, a means is taken to accelerate drying by adding a penetrant to the ink and allowing water to penetrate into the recording medium. Not only that, the penetrability 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 (Patent Document 1 (Japanese Patent No. 5001291)). Publication))). 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 printed image density can be improved by making it unstable with the Ca salt therein.
As the monomer constituting the polymer, 4-methacrylamide-1-hydroxybutane-1,1-diphosphonic acid is exemplified, but there is no example of the monomer represented by the formula (4) of the present invention. ) And a monomer represented by the formula (5), or a copolymer using the monomer represented by the formula (4) and the monomer represented by the formula (6). The effect on improving dispersion stability is not described.

Japanese Patent Application Laid-Open No. 2011-122072 discloses an ink used for recording on paper containing a water-soluble polyvalent metal salt. At this time, the ink includes (a) a pigment, (b) a functional group having no surface activity, a molecular weight of 150 or more and 10,000 or less, and having phosphoric acid as a basic skeleton in the molecular structure. And a phosphoric acid-based functional group and a phosphonic acid as a basic skeleton having a phosphorus content ((P content / molecular weight) x 100) of 1.4 or more. It contains at least one compound having a functional group selected from functional groups, and (b) the content (% by mass) of the compound is 1.5% by mass or more and 10.0% by mass based on the total mass of the ink. It is characterized by the following.
Patent Document 2 exemplifies monomers represented by the formulas (5) and (6) in the present invention as monomers for the copolymer, but the monomer represented by the formula (4) in the present invention. There is no exemplification of a copolymer using the above, and the effect of improving the image density and improving the pigment dispersion stability in plain paper having a low content of water-soluble polyvalent metal salt is not described.

  In Patent Document 1, the polymer is not used as a dispersant and additive for the pigment dispersion, but the polymer is coated with a colorant, and the functional group of the polymer is adjacent to a diphosphonic acid group and a hydroxyl group. Therefore, there is a problem that the hydrogen dispersion between the diphosphonic acid group and the hydroxyl group is likely to occur or the dispersion stability of the ink is low.

An object of the present invention is to solve the above-described problems and achieve the following objects.
That is, it is an object of the present invention to provide an ink for ink jet recording, which can obtain a high image density, reduce image back-through, and has good pigment dispersion and dispersion stability of the pigment as the ink. To do.

  As a result of intensive studies, the present inventors have used a copolymer having a bisphosphonic acid group and a specific structural unit as a component of the ink for ink-jet recording, so that the ink for ink-jet recording is aggregated on the paper surface. As a result, the present inventors have found that a high image density can be obtained due to the retention of the pigment in the image, the back-through of the image is reduced, and further, the dispersion of the pigment as the pigment dispersion and the ink becomes stable.

（式（１）中のＲ₁は、水素またはメチル基を表す。Ｍは、水素、アルカリ金属、または有機アンモニウムを表す。）

That is, the above problem is an ink for ink jet recording having at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphonic acid group, wherein the copolymer containing the phosphonic acid group is represented by the following formula (1). This is solved by an ink for ink jet recording characterized by having at least a structural unit represented by the following formula (2) and / or a structural unit represented by the following formula (3).

(R ₁ in formula (1) represents hydrogen or a methyl group. M represents hydrogen, an alkali metal, or organic ammonium.)

  According to the present invention, it is possible to provide an ink for ink jet recording, which can obtain a high image density, reduce the back-through of the image, and has a good dispersion stability of the pigment dispersion and the pigment as the ink.

It is a schematic plan view for demonstrating an example of the ink storage container of this 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 sectional view of the ink jet recording apparatus shown in FIG. 3.

（式（１）中のＲ₁は、水素またはメチル基を表す。Ｍは、水素、アルカリ金属、または有機アンモニウムを表す。）

The ink for inkjet recording of the present invention contains at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphonic acid group, and the copolymer containing the phosphonic acid group is represented by the following formula (1). It is characterized by having at least a structural unit and a structural unit represented by the following formula (2) and / or the following formula (3).

(R ₁ in formula (1) represents hydrogen or a methyl group. M represents hydrogen, an alkali metal, or organic ammonium.)

Phosphoric acid groups and phosphonic acid groups are hydrophilic, but are characterized by reacting with polyvalent metal ions such as calcium ions, magnesium ions, and aluminum ions to make them hydrophobic. Therefore, an inkjet recording ink using a copolymer containing a phosphoric acid group or a phosphonic acid group as a pigment dispersing agent has a pigment dispersing agent adsorbed on the pigment when used in a recording medium containing a water-soluble polyvalent metal salt. Aggregation of the pigment occurs by reacting with the polyvalent metal ions eluted from the recording medium to be hydrophobized. As a result, the penetration of the pigment into the paper can be suppressed, a high image density can be obtained, and the back-through where the image can be seen through from the back side of the paper surface can be reduced.
However, PPC plain paper containing almost no water-soluble polyvalent metal salt has a small amount of polyvalent metal ions eluted from the recording medium, and the effect of improving the image density by aggregation of the pigment is insufficient. .

  As a method of solving the above problems, a method of using a copolymer containing a bisphosphonic acid group as a hydrophilic functional group or a method of increasing the ratio of the hydrophobic structural unit of the pigment dispersant to enhance the adsorption of the dispersant and the pigment Can be considered. However, when bisphosphonic acid groups are introduced into the copolymer, the interaction between the phosphonic acid groups becomes stronger, resulting in a decrease in pigment dispersibility or an increase in viscosity when the pigment dispersion and 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.

  In the present invention, the following effects can be obtained by combining the structural unit represented by the formula (2) and / or the formula (3) in addition to the structural unit represented by the formula (1). A high image density can be obtained even on plain paper containing only a low salt content or a hardly soluble metal salt. Further, the dispersion stability of the pigment in the pigment dispersion and the ink could be ensured.

The effect of each structural unit represented by Formula (1), Formula (2), and Formula (3) will be described in detail below.
(1) The introduction of the structural unit represented by formula (1) increases the reactivity of the copolymer with metal ions, and the pigment is likely to aggregate when ink containing the copolymer lands on paper. became. As a result, a very high image density was obtained.
(2) By introducing the structural unit represented by the formula (2) and / or the formula (3), the adsorptive power of the copolymer to the pigment is improved, and the dispersibility stability of the pigment when used as a dispersant. Improved. Further, when the copolymer reacts with metal ions, the pigment is easily aggregated, and as a result, the image density is improved.

  An ink jet recording apparatus having ink ejecting means for ejecting the ink for ink jet recording of the present invention from an ink jet head to record an image on a recording medium, and applying ink through the ink ejecting means to eject ink from the recording head. If an image is recorded on a recording medium, high density image formation can be realized. Further, if the ink for ink jet recording of the present invention is accommodated in a container to be an ink container, the ink can be easily attached to and detached from the ink container loading portion provided in the ink jet recording apparatus, and stable ink supply for a long period of time can be achieved. It becomes possible. The ink recorded matter of the present invention has high image quality and excellent stability over time, and can be suitably used for various applications as materials on which various prints or images are recorded.

［式（１）中、Ｒ₁は、水素、及びメチル基のいずれかを表す。Ｍは、水素、アルカリ金属、または有機アンモニウムを表す。］

<Copolymer containing phosphonic acid group>
The copolymer containing a phosphonic acid group of the present invention (hereinafter also referred to as polymer) has a structural unit represented by the following formula (1) and a structure represented by the following formula (2) and / or the following formula (3). Unit, and, if necessary, other structural units.

[In formula (1), R ₁ represents either hydrogen or a methyl group. M represents hydrogen, an alkali metal, or organic ammonium. ]

Examples of the alkali metal M in the formula (1) include lithium, sodium, potassium, and the like.
Examples of M organic ammonium include alkylamines such as mono-, di- or trimethylamine, mono-, di- or triethylamine; ethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, dimethylethanolamine, monopropanolamine , Alcohols such as dipropanolamine, tripropanolamine, isopropanolamine, trishydroxymethylaminomethane, 2-amino-2-ethyl-1,3-propanediol (AEPD); choline, morpholine, N-methylmonoformin And cyclic amines such as N-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 to the total number of M in the formula (1) constituting the copolymer is preferably 0% to 40%, and the remainder is preferably an alkali metal or organic ammonium.

The ratio (%) of hydrogen to the total number of M in the copolymer can be determined as 100% -neutralization rate (%) using the neutralization rate (%) defined below.
In the present invention, the neutralization rate of the phosphonic acid group in the polymer obtained by the neutralization treatment is defined as the neutralization rate as determined by the following method. This is different from the ratio in which protons are substituted with metal ions or organic amine ions.
When the compound represented by formula (4) is monomer 1,
Neutralization rate X (%) = (number of moles of added base x base cation valence)
÷ (number of moles of monomer 1 contained in polymer × 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 polymer
= Charge amount of monomer 1 Zg / Molecular weight of monomer 1 Therefore, the amount of base necessary to obtain the neutralization rate X% is: Base addition amount Yg = Neutralization rate X (%) x (Feed amount of monomer 1 Zg × 4)
X base molecular weight / (base cation valence x 100 x monomer 1 molecular weight)
It becomes.

［Ｍは、水素、アルカリ金属、または有機アンモニウムを表す。］ The structural unit represented by the formula (1) of the polymer is preferably a structural unit represented by the following formula (7).

[M represents hydrogen, an alkali metal, or organic ammonium. ]

In addition to the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3), the polymer further includes a structural unit derived from a polymerizable monomer. You can also.
There is no restriction | limiting in particular as said polymerizable monomer, According to the objective, it can select suitably. Examples thereof include a polymerizable hydrophobic monomer and a polymerizable hydrophilic monomer.

  The polymerizable hydrophobic monomer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include aromatics such as styrene, α-methylstyrene, 4-t-butylstyrene, and 4-chloromethylstyrene. Unsaturated ethylene monomer having an aromatic ring; methyl (meth) acrylate, ethyl (meth) 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), (meth) acrylic acid ray Alkyl (meth) acrylates such as syl (C20), heicosyl (meth) acrylate (C21), 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, 1-octadecene, 1-nonadecene, 1-eicocene, 1-docose, etc. Monomer, and the like. These may be used individually by 1 type and may use 2 or more types together.

  The polymerizable hydrophilic monomer is not particularly limited and may be appropriately selected depending on the purpose. For example, (meth) acrylic acid or a salt thereof, maleic acid or a salt thereof, monomethyl maleate, itaconic acid, Anionic unsaturated ethylene monomers such as monomethyl itaconic acid, fumaric acid, 4-styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid; (meth) acrylic acid-2-hydroxyethyl, 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- dimethylacrylamide, 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 formula (1) is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5% by mass to 80% by mass with respect to the total amount of the polymer. 10 mass%-60 mass% are more preferable, and 30 mass%-50 mass% are still more preferable. When the mass ratio is within the more preferable range, it is advantageous in that when used for an ink jet recording ink, a high image density is obtained, and dispersion stability and storage stability are improved.

  Further, the mass ratio of the structural unit represented by the formula (2) and / or the formula (3) in the polymer is not particularly limited as long as it is set in the remaining ratio after setting the ratio of the formula (1). And can be appropriately selected according to the purpose. 20 mass%-95 mass% are preferable with respect to the said polymer whole quantity especially, 40 mass%-90 mass% are more preferable, and 50 mass%-70 mass% are still more preferable. When the mass ratio is in the preferred range, it is advantageous in that when used for an ink jet recording ink, a high image density is obtained, and dispersion stability and storage stability are good.

  The polymer containing the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3) is produced by the polymer production method of the present invention described below. be able to. The polymer containing the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3) is not particularly limited and can be widely used in various fields. However, it can be suitably used as a pigment dispersant, a pigment concentration improver, a pigment binder resin, a viscosity modifier and the like in an ink for inkjet recording.

（式（４）中のＲ₂は、水素またはメチル基を表す。）

<Method for producing copolymer containing phosphonic acid group>
The copolymer containing a phosphonic acid group is synthesized using at least a monomer represented by the following formula (4) and a monomer represented by the following formula (5) and / or the following formula (6) as starting materials. Can do.

(R ₂ in formula (4) represents hydrogen or a methyl group.)

  The method for producing a copolymer containing a phosphonic acid group used in the present invention polymerizes at least a monomer represented by formula (4) and a monomer represented by formula (5) and / or formula (6). Then, it is preferable to include a step of neutralizing the obtained polymer with either an alkali metal base or an organic amine base, and further include other steps as necessary.

The polymer containing the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3) includes a monomer represented by the formula (4) and a formula (5). ) Or a monomer represented by formula (6), or a monomer represented by formula (4) below, a monomer represented by formula (5) and / or formula (6), and It can be synthesized by copolymerizing a polymerizable monomer and then neutralizing with either an alkali metal base or an organic amine base.
In addition, the monomer represented by the formula (4) is previously neutralized with either an alkali metal base or an organic amine base, and then copolymerized with the monomer represented by the formula (5) and / or the formula (6). Even synthesis is possible.

Examples of the monomer represented by the formula (4) include 1-methacryloxyethane-1,1-diphosphonic acid represented by the following structural formula (8) in which R ₂ is a methyl group, and R ₂ is hydrogen. Specific examples include 1-acryloxyethane-1,1-diphosphonic acid represented by the following formula (9). These compounds can be synthesized, for example, by the method described in JP-A-58-2222095.

As a method for synthesizing a polymer containing the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3), the polymerization operation and the adjustment of the molecular weight are easy. Therefore, a method using a radical polymerization initiator is preferable, and a solution polymerization method in which polymerization is performed in an organic solvent is more preferable.
The solvent for performing radical polymerization by the solution polymerization method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ketone solvents such as methanol, ethanol, acetone, methyl ethyl ketone, and methyl isobutyl ketone; Examples thereof include acetate solvents such as ethyl acetate and 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.

The radical polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose. For example, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, peroxyester Cyano azobisisobutyronitrile, azobis (2-methylbutyronitrile), azobis (2,2′-isovaleronitrile), non-cyano dimethyl-2,2′-azobisisobutyrate, Etc. 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.
The content of the polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1% by mass to 10% by mass with respect to the total mass of the polymerizable monomer.

In order to adjust the molecular weight of the polymer, 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 superposition | polymerization temperature, Although it can select suitably according to the objective, 50 to 150 degreeC is preferable and 60 to 100 degreeC is more preferable. The polymerization time is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 3 hours to 48 hours.

The obtained polymer is neutralized with either an alkali metal base or an organic amine base.
The neutralization treatment can be performed by neutralizing some or all of the phosphonic acid groups of the polymer with an alkali metal base or an organic amine base.
The neutralization treatment of the alkali metal base or organic amine base can also be performed in a state where the pigment and the polymer are mixed in the ink production process.

  The polymer containing the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3) is more specifically a stirrer, a thermometer, and nitrogen introduction. In a flask equipped with a tube, a solvent, a monomer represented by the formula (4), a monomer represented by the formula (5) and / or the formula (6), and a polymerizable monomer as necessary are polymerized. It can synthesize | combine by making it react at the temperature of 50 to 150 degreeC under nitrogen gas recirculation | reflux in the presence of an initiator, and then neutralizing with either an alkali metal base or an organic amine base.

  The viscosity of the 10% by weight aqueous solution or 10% by weight aqueous dispersion of the copolymer is preferably in the range of 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. When it is 30.0 mPa · s or less, the dispersion stability of the pigment is further improved, and the storage stability of the pigment dispersion is further improved. The viscosity is a value measured at 25 ° C. as will be described later.

The weight average molecular weight of the polymer containing the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3) is determined by the polymerization temperature, the polymerization initiator amount, and the reaction time. The monomer concentration can be controlled to some extent.
Regarding the polymerization temperature, a low molecular weight polymer tends to be obtained when polymerized at a high temperature in a short time, and a high molecular weight polymer tends to be obtained when polymerized at a low temperature for a long time.

(Inkjet recording ink)
The ink for inkjet recording of the present invention is represented by water, a water-soluble organic solvent, a pigment, the structural unit represented by the formula (1) of the present invention, and the formula (2) and / or the formula (3). It contains a polymer containing a structural unit, and further contains other components as necessary.
The content of the polymer including the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3) in the inkjet recording ink is 0. It is preferably 5% by mass to 10.0% by mass, and more preferably 1.0% by mass to 5.0% by mass. The addition of 0.5% by mass clearly shows the effect of improving the image density, and by making it 10.0% by mass or less, it is possible to suppress the viscosity to a range suitable for discharging ink from the head.

In addition, the ink for inkjet recording of the present invention is preferably formed by mixing at least a pigment, water, and an aqueous dispersion of a pigment composed of a copolymer containing the phosphonic acid group and a water-soluble solvent. .
If a polymer containing the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3) is used as a pigment dispersant, an image on plain paper is further obtained. Further improvement in storage stability with ink having a high concentration and content of water-soluble organic solvent is observed. When used as the pigment dispersant, in addition to the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3), hydrophilic polymerizable Monomer-derived structural units can be included. As the hydrophilic polymerizable monomer, those described above can be used.
The content of the polymer containing the structural unit represented by the formula (1) and the structural unit represented by the formula (2) and / or the formula (3) is particularly when used as a pigment dispersant. Although there is no restriction | limiting and it can select suitably according to the objective, The mass ratio of the pigment and copolymer in the aqueous dispersion of the said pigment should be pigment / copolymer = 100 / 10-100 / 100. Preferably, 100 / 15-100 / 50 is more preferable. When the content is within the more preferable range, a high image density can be obtained, and further, the storage stability of the ink in which the water-soluble solvent exceeds 20% by mass or more is further improved. Moreover, you may use together the dispersing agent described later with a copolymer in the range which does not impair the said effect.

(water)
As water used in the present invention, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used.
The water content is preferably 20 to 60% by mass with respect to the total amount of ink.

(Water-soluble solvent)
The water-soluble solvent used in the present invention is necessary for improving the ejection stability by providing a moisturizing effect in the ink composition. The content is preferably 10 to 50% by mass with respect to the total amount of ink. When the content is 10% by mass or more, it is difficult for the ink to evaporate water, and the ink supply system in the ink jet recording apparatus is suppressed from evaporating the ink, and ink clogging is less likely to occur. When the content is 50% by mass or less, the ink viscosity can be kept 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 used in the present invention include, but are not limited to, the following. For example, 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 -Polyhydric alcohols such as butanetriol, petriol, trimethylolpropane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono Polyhydric alcohol alkyl ethers such as chill ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl- Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide Amides such as monoethanolamine, diethanolamine, and triethylamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol, propylene carbonate DOO, an ethylene carbonate.
These water-soluble solvents can be used alone or in combination of two or more.

  Among these, the inclusion of 1,3-butanediol, diethylene glycol, 2,2,4-trimethyl-1,3-pentanediol, triethylene glycol and / or glycerin is excellent in preventing discharge failure due to moisture evaporation. Effect. In particular, glycerin is preferably included.

(Pigment)
The content of the pigment used in the present invention in the recording ink is preferably 0.1% by mass or more and 20.0% by mass or less. The volume average particle diameter (D50) of the pigment is preferably 150 nm or less.
Here, the volume average particle diameter (D50) of the pigment is measured by a dynamic light scattering method using Microtrac UPA manufactured by Nikkiso Co., Ltd. in an environment of 23 ° C. and 55% RH.

There is no restriction | limiting in particular as these pigments, According to the objective, it can select suitably, For example, any of an inorganic pigment and an organic pigment may be sufficient. These may be used individually by 1 type and may use 2 or more types together.
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 phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, rhodamine B lake pigments, and the like. It is done. Examples of the dye chelates include basic dye chelates and acidic dye chelates.

Examples of black materials include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), titanium oxide, and the like. And organic pigments such as aniline black (CI Pigment Black 1).
As the carbon black, a furnace method, a carbon black produced by the channel method, primary particle diameter of, 15Nm～40nm, specific surface area by BET ^{method, 50m 2 / g~300m 2 / g} , DBP oil absorption amount 40ml / 100 g to 150 ml / 100 g, those having a volatile content of 0.5% to 10% and a pH value of 2 to 9 are preferred.

  A commercially available product can be used as the carbon black. Examples of commercially available products 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 Columbia); Regal400R, 330R, 660R, Mogu L, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot); 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).

  The pigment that can be used for the yellow ink for color is not particularly limited and can be appropriately selected according to the purpose. 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.

  The pigment that can be used in the magenta ink for color is not particularly limited and may be appropriately selected depending on the intended purpose. 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.

  The pigment that can be used for the cyan ink for the color is not particularly limited and may be appropriately selected according to the purpose. 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.

In addition, the pigment contained in each ink used in the present invention may be newly produced for the present invention.
By using Pigment Yellow 74 as the yellow pigment, Pigment Red 122, Pigment Bio Red 19 as the magenta pigment, and Pigment Blue 15: 3 as the cyan pigment, an ink with excellent color tone and light fastness and balanced can be obtained. Can be obtained.
Further, the pigment used in the present invention may be a grafted or encapsulated product coated with a surfactant such as a dispersant or a resin. More preferably, the coalescence is used as a dispersant.
Moreover, you may use together the pigment mentioned above in the range which does not impair an effect.

(Other ingredients)
There is no restriction | limiting in particular as another component used for the composition of the ink for inkjet recording of this invention, It can select suitably as needed. Examples of other components include a dispersant, a pH adjuster, a water-dispersible resin, an antiseptic / antifungal agent, a chelating reagent, a rust inhibitor, an antioxidant, an ultraviolet absorber, an oxygen absorber, and a light stabilizer. Is mentioned.

(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, Derivatives and the like.
Examples of nonionic surfactants include the following.
Ether-based interfaces such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyallylalkyl alkyl ether Active 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 Examples thereof include acetylene glycol surfactants.

(PH adjuster)
The pH adjuster is not particularly limited as long as the pH can be adjusted to 8.5 to 11 and preferably 9 to 11 without adversely affecting the ink jet ink to be prepared. For example, alcohol amines, hydroxides of alkali metal elements, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like can be used. When the pH is less than 8.5 or more than 11, the amount of the ink jet head or ink supply unit that melts out is large, and problems such as ink deterioration, leakage, and ejection failure may occur. 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, 2-amino-2-ethyl-1,3-propanediol, and the like. 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, and 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)
The water-dispersible resin has excellent film-forming properties (image formability), high water repellency, high water resistance, and high weather resistance, and has high water resistance and high image density (high color development). Useful for.
Specific examples of the water-dispersible resin include condensation-type synthetic resins, addition-type synthetic resins, natural polymer compounds, and the like.
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 though they are 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 disturb the ink ejection stability.
Here, the volume average particle diameter (D50) of the water-dispersible resin is measured by a dynamic light scattering method using Microtrac UPA manufactured by Nikkiso Co., Ltd. in an environment of 23 ° C. and 55% RH.

The water-dispersible resin has a function of fixing the water-dispersed pigment on the paper surface, and is preferably formed into 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.
Further, when the glass transition temperature of the water-dispersible resin is -40 ° C. or lower, the resin film becomes more viscous and the printed matter is tacky. Therefore, the water-dispersible resin has a glass transition temperature of −30 ° C. or higher. It is preferable. The content of the water-dispersible resin in the inkjet 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 ink manufacturing method)
The ink-jet ink of this embodiment is obtained by dispersing or dissolving water, a water-soluble solvent, a pigment, a copolymer containing a phosphonic acid group, and other components in an aqueous medium as required, and further if necessary. Produced by stirring and mixing.
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, and the like. be able to.
When a copolymer containing a phosphonic acid group is used as a dispersant for the pigment, an aqueous dispersion of a pigment composed of at least the pigment, water, and the copolymer containing the phosphonic group, and a water-soluble solvent are added to water. Dispersed or dissolved, and further stirred and mixed as necessary.

There is no restriction | limiting in particular as a physical property of the inkjet ink of this invention, According to the objective, it can select suitably, For example, it is preferable that viscosity, surface tension, etc. are the following ranges.
The viscosity of the inkjet ink at 25 ° C. is preferably 3 mPa · s to 20 mPa · s. By setting the ink viscosity to 3 mPa · s or more, the effect of improving the printing density and the character quality can be obtained. On the other hand, by suppressing the ink viscosity to 20 mPa · s or less, it is possible to ensure the discharge performance.
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 inkjet 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 for storing the ink for ink jet recording of the present invention, and can further constitute other members appropriately selected as necessary.
The shape, structure, size, and material of the container are not particularly limited and can be appropriately selected according to the purpose. Preferred examples include those having at least an ink containing portion formed of an aluminum laminate film, a resin film, or the like.

One embodiment of the ink container of the present invention will be described with reference to FIGS. FIG. 1 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 shown in FIG.
As shown in FIG. 1, the ink container 200 is filled into the ink container 241 from the ink inlet 242 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 a recording medium using the ink jet recording ink of the present invention using an ink jet head. The ink jet recording apparatus of the present invention includes at least ink flying means for discharging ink, and further includes other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.
The ink jet recording method using the ink of the present invention includes at least an ink flying process, and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.
The ink jet recording method can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.

The ink flying step is a step of forming an image by applying a stimulus to the ink jet recording ink of the present invention and causing the ink jet recording ink to fly.
The ink flying means is means for forming an image by applying a stimulus to the ink jet recording ink of the present invention and causing the ink jet recording ink to fly. The ink flying means is not particularly limited, and examples thereof include various nozzles for ejecting ink.

  The stimulus can be generated, for example, by 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. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferable. Examples of the stimulus generating means include a superheater, a pressurizer, a piezoelectric element, a vibration generator, 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 flying, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, the thermal energy corresponding to the recording signal is output to the ink in the recording head. For example, using a thermal head or the like, generating bubbles in the ink by the thermal energy, and ejecting and ejecting the ink as droplets from the nozzle holes of the recording head by the pressure of the bubbles. It is done. Further, 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 bends and the volume of the pressure chamber is increased. And a method of ejecting and ejecting the ink as droplets from the nozzle holes of the recording head.

  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 aspect of carrying out the ink jet recording method by the ink jet recording apparatus of the present invention will be described with reference to the drawings.
FIG. 3 is a perspective view showing an example of the serial type ink jet recording apparatus of the present invention.
The ink jet recording apparatus shown in FIG. 3 stocks an apparatus main body 101, a paper feed tray 102 for loading paper loaded on the apparatus main body 101, and paper on which an image is recorded (formed) mounted on the apparatus main body 101. A discharge tray 103 for printing, and an ink container container loading unit 104 that protrudes forward from the front surface 112 and is lower than the upper cover 111 are provided at 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.

  As shown in FIGS. 4 and 5 (partially enlarged sectional view of the ink jet recording apparatus shown in FIG. 3), a guide which is a guide member horizontally mounted on left and right side plates (not shown) is provided in the apparatus main body 101. The carriage 133 is slidably held in the main scanning direction by the rod 131 and the stay 132, and is moved and scanned in the direction of the arrow as shown in FIG. 5 by the main scanning motor.

  The carriage 133 is provided with a recording head 134 composed of four ink jet recording heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.

  As the ink jet recording head constituting the recording head 134, a piezoelectric actuator such as a piezoelectric element, a thermal actuator using phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a metal phase due to temperature change, etc. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging 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 replenished with the ink supplied from the ink container 200 of the present invention loaded in the ink container loading unit 104 via an ink supply tube (not shown).

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 having a thickness of about 40 μm that is not subjected to resistance control, for example, a copolymer of tetrafluoroethylene and ethylene (ETFE), and the surface layer. It has a back layer (medium resistance layer, earth layer) that is made of the same material and has resistance controlled by carbon. 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 conveying belt 151 is charged by the charging roller 156, and the sheet 142 is electrostatically attracted to the conveying belt 151 and conveyed. 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 of the present invention is used up, the casing of the ink container 200 can be disassembled and only the ink container inside can be replaced. Further, the ink container 200 can supply ink stably even if it 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 recordings 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 ink recorded matter recorded by the ink jet recording method of the present invention is the recorded matter of the present invention. That is, in the recorded matter of the present invention, information or an image is recorded on a recording medium (recording medium) using the ink for ink jet recording of the present invention. The recorded matter of the present invention can be produced by a process of recording on a recording medium by discharging ink for inkjet recording 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, coated paper for printing, glossy paper, special paper, cloth, film, and OHP sheet. It is done. These may be used individually by 1 type and may use 2 or more types together. Among these, at least one of plain paper and coated paper for printing is preferable. The plain paper is advantageous in that it is inexpensive. The coated paper for printing is advantageous in that it provides a smooth glossy image at a relatively low cost as compared with glossy paper. However, plain paper and coated paper for printing have low image density and poor drying, and are generally not preferred for use in ink jet printing. The ink of the present invention can be used on plain paper and coated paper for printing with improved image density and dryness.
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.

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 ^{−5 to} 5.0 × 10 ⁻⁴ [g / g]. When the Ca ion amount is 1.0 × 10 ⁻⁵ [g / g] or more, the effect of improving the image density by reaction aggregation with the pigment dispersant is improved. In addition, when the Ca ion amount is 5.0 × 10 ⁻⁴ [g / g] or less, the penetration of the ink into the paper is not inhibited, so that the drying property of the ink is improved, and the scratch resistance and the marker resistance are also improved. improves.
For example, the amount of Ca ions of MyPaper (plain paper manufactured by Ricoh Co., Ltd.) is 4.3 × 10 ⁻⁴ [g / g].

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 of paper. 16 g of the cut paper piece is immersed in 200 g of high-purity water at 25 ° C. for 40 hours. High purity water (immersion liquid) after dipping a piece of paper is filtered through a 0.8 μm cellulose acetate filter (manufactured by Advantech) to remove foreign substances such as paper dust, and then CaP contained in the immersion liquid is analyzed by ICP emission spectrometry. Quantify by instrument. 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.

（式（１）中のＲ₁は、水素またはメチル基を表す。Ｍは、水素、アルカリ金属、または有機アンモニウムを表す。）

（２）少なくとも水、水溶性溶剤、顔料、及びホスホン酸基を含む共重合体を有するインクジェット記録用インクであって、前記ホスホン酸基を含む共重合体が、下記式（４）で表されるモノマーと、下記式（５）及び／又は下記式（６）で表されるモノマーとを少なくとも出発物質として合成されたものであることを特徴とするインクジェット記録用インク。

（式（４）中のＲ₂は、水素またはメチル基を表す。）

（３）前記ホスホン酸基を含む共重合体における前記式（１）の構造単位の含有率又は前記式（４）で表されるモノマーの含有率が１０質量％〜６０質量％であることを特徴とする前記（１）又は（２）に記載のインクジェット記録用インク。
（４）前記ホスホン酸基を含む共重合体の固形分１０質量％の水溶液または水分散液の粘度が１．５〜３０．０ｍＰａ・ｓであることを特徴とする前記（１）乃至（３）のいずれかに記載のインクジェット記録用インク。
（５）少なくとも顔料、水、及び前記ホスホン酸基を含む共重合体から構成される顔料の水分散液と、水溶性溶剤とを少なくとも混合してなることを特徴とする前記（１）乃至（４）のいずれかに記載のインクジェット記録用インク。
（６）前記顔料の水分散液における顔料とホスホン酸基を含む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前記（５）に記載のインクジェット記録用インク。
（７）前記共重合体を構成する式（１）のＭが水素またはカリウムまたはナトリウムであることを特徴とする前記（１）、（３）乃至（６）のいずれかに記載のインクジェット記録用インク。
（８）前記共重合体を構成する式（１）のＭの総数に対する水素の割合が０％〜４０％であることを特徴とする前記（１）、（３）乃至（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前記（１）乃至（８）のいずれかに記載のインクジェット記録用インク。
（１０）インクを収容するインク収容部を備えたインク収容容器であって、前記インク収容部に収容されたインクが、前記（１）乃至（９）のいずれかに記載のインクジェット記録用インクであることを特徴とするインク収容容器。
（１１）インクをインクジェットヘッドを用いて記録媒体に情報または画像を記録するインクジェット記録装置であって、前記インクが、前記（１）乃至（９）のいずれかに記載のインクジェット記録用インクであることを特徴とするインクジェット記録装置。
（１２）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記録物の製造方法であって、前記インクが、前記（１）乃至（９）のいずれかに記載のインクジェット記録用インクであることを特徴とする記録物の製造方法。
（１３）インクを用いて記録媒体に情報または画像が記録されている記録物であって、前記インクが、前記（１）乃至（９）のいずれかに記載のインクジェット記録用インクであることを特徴とする記録物。 Further, the present invention relates to the following ink for inkjet recording (1), and includes the following (2) to (13) as embodiments.
(1) An inkjet recording ink having a copolymer containing at least water, a water-soluble solvent, a pigment, and a phosphonic acid group, wherein the copolymer containing the phosphonic acid group is represented by the following formula (1): An inkjet recording ink comprising at least a structural unit and a structural unit represented by the following formula (2) and / or the following formula (3):

(R ₁ in formula (1) represents hydrogen or a methyl group. M represents hydrogen, an alkali metal, or organic ammonium.)

(2) An ink for inkjet recording having at least water, a water-soluble solvent, a pigment, and a copolymer containing a phosphonic acid group, wherein the copolymer containing the phosphonic acid group is represented by the following formula (4): An ink for inkjet recording, which is synthesized using at least a monomer represented by the following formula (5) and / or a monomer represented by the following formula (6) as a starting material.

(R ₂ in formula (4) represents hydrogen or a methyl group.)

(3) The content of the structural unit of the formula (1) in the copolymer containing the phosphonic acid group or the content of the monomer represented by the formula (4) is 10% by mass to 60% by mass. The ink for ink-jet recording described in (1) or (2), which is characterized in that
(4) Said (1) thru | or (3) characterized by the viscosity of the aqueous solution or water dispersion of 10 mass% solid content of the copolymer containing the said phosphonic acid group being 1.5-30.0 mPa * s. ) Ink for ink jet recording according to any of the above.
(5) Said (1) thru | or () characterized by comprising at least a pigment, water, and the aqueous dispersion of the pigment comprised from the said copolymer containing the said phosphonic acid group, and a water-soluble solvent. 4) Ink for ink jet recording according to any one of the above.
(6) The mass ratio of the pigment and the copolymer containing a phosphonic acid group in the aqueous pigment dispersion is pigment / copolymer = 100/10 to 100/100. The ink for inkjet recording as described.
(7) The inkjet recording according to any one of (1), (3) to (6), wherein M in the formula (1) constituting the copolymer is hydrogen, potassium, or sodium ink.
(8) The ratio of hydrogen to the total number of M in the formula (1) constituting the copolymer is 0% to 40%, any one of (1), (3) to (7) 2. Ink for ink jet recording described in 1.
(9) The ink for ink-jet recording according to any one of (1) to (8), wherein the water-soluble solvent contains at least glycerin.
(10) An ink storage container including an ink storage unit that stores ink, wherein the ink stored in the ink storage unit is the ink for inkjet recording according to any one of (1) to (9). An ink container that is characterized by being.
(11) An ink jet recording apparatus that records information or an image on a recording medium using an ink jet head, wherein the ink is the ink for ink jet recording according to any one of (1) to (9). An ink jet recording apparatus.
(12) A method of manufacturing a recorded matter including a step of recording on a recording medium by discharging ink from an inkjet head, wherein the ink is for inkjet recording according to any one of (1) to (9). A method for producing a recorded matter, characterized by being ink.
(13) A recorded matter in which information or an image is recorded on a recording medium using ink, wherein the ink is the ink for ink jet recording according to any one of (1) to (9). Characteristic recorded matter.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples. “Part” represents “part by mass” unless otherwise specified. “%” Represents “% by mass” unless otherwise specified.

(Measurement of copolymer viscosity)
The viscosity of the 10% by mass aqueous solution or 10% by mass aqueous dispersion of the synthesized copolymer was measured at 25 ° C. using a rotational viscometer (viscosity meter RE80L, cone plate type, manufactured by Toki Sangyo Co., Ltd.). Specific operations are shown below. 1.1 mL of a 10% by weight aqueous solution or 10% by weight aqueous dispersion of the copolymer was sampled and placed in a sample cup of a viscometer. After the sample cup was attached to the viscometer body and allowed to stand for 1 minute, the viscometer rotor was rotated and the value after 1 minute was read. About the rotation speed at the time of a viscosity measurement, it adjusted so that a torque might become fixed in 40%-80% of range.

<Synthesis of copolymer compound>
(Synthesis Example 1)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 40.0 parts by mass of the compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 60.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 1 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 3.3 mPa · s.

(Synthesis Example 2)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 40.0 parts by mass, a compound represented by the structural formula (6), (2-vinylnaphthalene) 60.0 parts by mass, polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 2 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 3.1 mPa · s.

(Synthesis Example 3)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (9) (1-acryloxyethane-1,1-diphosphonic acid) In the general formula (4), 40.0 parts by mass of a compound in which R ₂ is hydrogen, a compound represented by the structural formula (5), 60.0 parts by mass of (1-vinylnaphthalene), a polymerization initiator 4.0 parts by mass of (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 3 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 2.9 mPa · s.

(Synthesis Example 4)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 15.0 parts by mass, a compound represented by the structural formula (5), (1-vinylnaphthalene) 85.0 parts by mass, polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 75 ° C. Next, after carrying out the polymerization reaction for 3 hours under a nitrogen stream, after distilling about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 4 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 1.1 mPa · s.

(Synthesis Example 5)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group, 5.0 parts by mass, a compound represented by the structural formula (5), (1-vinylnaphthalene, 95.0 parts by mass, polymerization initiation 4.0 parts by mass of an agent (azubisisobutyronitrile) was added, and the temperature was raised to 65 ° C. Next, after carrying out a polymerization reaction for 5 hours in a nitrogen stream, about half of the charged solvent was added from the reaction system. Then, the mixture was poured into acetone to precipitate a polymer, which was further dried to obtain a polymer.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 5 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 1.6 mPa · s.

(Synthesis Example 6)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 15.0 parts by mass, a compound represented by the structural formula (5), (1-vinylnaphthalene) 85.0 parts by mass, polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 5 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 6 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 1.7 mPa · s.

(Synthesis Example 7)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 55.0 parts by mass of a compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 45.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 75 ° C. Next, after carrying out the polymerization reaction for 3 hours under a nitrogen stream, after distilling about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 7 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 1.0 mPa · s.

(Synthesis Example 8)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 65.0 parts by mass, a compound represented by the structural formula (5), 35.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 5 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 8 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 1.8 mPa · s.

(Synthesis Example 9)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 55.0 parts by mass of a compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 45.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 5 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 9 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 1.8 mPa · s.

(Synthesis Example 10)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 55.0 parts by mass of a compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 45.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 50 ° C. Next, after carrying out the polymerization reaction for 48 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer was precipitated by pouring the mixture into acetone, and further dried, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 10 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 31.5 mPa · s.

(Synthesis Example 11)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 65.0 parts by mass, a compound represented by the structural formula (5), 35.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 50 ° C. Next, after performing a polymerization reaction for 24 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 11 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 29.1 mPa · s.

(Synthesis Example 12)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 55.0 parts by mass of a compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 45.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 50 ° C. Next, after performing a polymerization reaction for 24 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 12 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 29.0 mPa · s.

(Synthesis Example 13)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 15.0 parts by mass, a compound represented by the structural formula (5), (1-vinylnaphthalene) 85.0 parts by mass, polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 50 ° C. Next, after carrying out the polymerization reaction for 48 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer was precipitated by pouring the mixture into acetone, and further dried, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 13 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 35.2 mPa · s.

(Synthesis Example 14)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 5.0 parts by mass, a compound represented by the structural formula (5), 95.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 50 ° C. Next, after performing a polymerization reaction for 24 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 14 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 29.9 mPa · s.

(Synthesis Example 15)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 15.0 parts by mass, a compound represented by the structural formula (5), (1-vinylnaphthalene) 85.0 parts by mass, polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 50 ° C. Next, after performing a polymerization reaction for 24 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 15 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 28.9 mPa · s.

(Synthesis Example 16)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 5.0 parts by mass, a compound represented by the structural formula (5), 95.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 75 ° C. Next, after carrying out the polymerization reaction for 3 hours under a nitrogen stream, after distilling about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 16 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 1.1 mPa · s.

(Synthesis Example 17)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), a compound in which R ₂ is a methyl group) 65.0 parts by mass, a compound represented by the structural formula (5), 35.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 50 ° C. Next, after carrying out the polymerization reaction for 48 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer was precipitated by pouring the mixture into acetone, and further dried, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 17 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 33.0 mPa · s.

(Synthesis Example 18)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 40.0 parts by mass of the compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 60.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, sodium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 18 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 3.2 mPa · s.

(Synthesis Example 19)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 40.0 parts by mass of the compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 60.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, lithium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 19 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 3.1 mPa · s.

(Synthesis Example 20)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 40.0 parts by mass of the compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 60.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, DMEA (dimethylethanolamine) was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 20 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 4.0 mPa · s.

(Synthesis Example 21)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 40.0 parts by mass of the compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 60.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 70% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 21 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 4.1 mPa · s.

(Synthesis Example 22)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 40.0 parts by mass of the compound in which R ₂ is a methyl group, a compound represented by the structural formula (5), 60.0 parts by mass of (1-vinylnaphthalene), polymerization initiation 4.0 parts by weight of an agent (azubisisobutyronitrile) was charged, and the temperature was raised to 65 ° C. Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 50% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 22 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 4.5 mPa · s.

(Synthesis Example 23)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol) and a compound represented by the structural formula (8) (1-methacryloxyethane-1,1-diphosphonic acid) In the general formula (4), 100.0 parts by mass of a compound in which R ₂ is a methyl group) and 4.0 parts by mass of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. . Next, after carrying out the polymerization reaction for 10 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 23 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 4.0 mPa · s.

(Synthesis Example 24)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (ethanol), 50.0 parts by mass of MAA (methacrylic acid), a compound represented by the structural formula (5), 10.0-vinylnaphthalene) and 50.0 parts by weight of a polymerization initiator (azubisisobutyronitrile) were charged, and the temperature was raised to 65 ° C. Next, after performing the polymerization reaction for 15 hours under a nitrogen stream, after distilling off about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into acetone, and further drying, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 24 in which the carboxylic acid group was neutralized 100% was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 15.0 mPa · s.

(Synthesis Example 25)
In a flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 500.0 parts by mass of a solvent (1-methoxy-2-propanol) and Phosmer M (2-metaquiloxyethyl acid phosphoate, Unichemical) 18 0.0 part by mass, St (styrene) 30.0 parts by mass, MMA (methyl methacrylate) 20.0 parts by mass, BMA (butyl methacrylate) 18.0 parts by mass, MAA (methacrylic acid) 10.0 parts by mass, 4.0 parts by mass of a polymerization initiator (azubisisobutyronitrile) was charged, and the temperature was raised to 110 ° C. Next, after carrying out the polymerization reaction for 4 hours under a nitrogen stream, after distilling about half of the charged solvent from the reaction system, the polymer is precipitated by pouring the mixture into methanol, and further dried, A polymer was obtained.
While diluting the obtained polymer with water, potassium hydroxide was added so as to achieve 100% acid neutralization, and the concentration was adjusted with water so that the solid concentration was 10% by mass. In this way, a copolymer 25 having 100% neutralized phosphonic acid groups was synthesized. The viscosity of a 10% by mass aqueous solution of the obtained copolymer at 25 ° C. was 11.5 mPa · s.

Table 1 shows the properties of the copolymers 1 to 25 synthesized as described above.

<Preparation Examples 1-36 of Pigment Dispersion>
Each material dispersion was prepared as follows.
(Pigment dispersion preparation example 1): Black pigment dispersion 1
A mixture of the following formulation (1) was premixed to prepare a mixed slurry (a). This was circulated and dispersed in a disk type media mill (manufactured by Ashizawa Finetech Co., Ltd., DMR type) using 0.05 mm zirconia beads and a filling rate of 55% at a peripheral speed of 10 m / s and a liquid temperature of 10 ° C. for 3 minutes. Coarse particles were centrifuged with a centrifuge (Model 7700, manufactured by Kubota Corporation) to obtain a pigment dispersion (pigment aqueous dispersion) having a pigment concentration of 16% by mass.
・ 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 by mass Copolymer 1 (Synthesis Example 1) ... 40 parts by mass Distilled water ... 800 parts by mass

(Pigment dispersion preparation example 2): Black pigment dispersion 2
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of the Pigment Dispersion Preparation Example 1 was changed to the Copolymer 2 (Synthesis Example 2). A black pigment dispersion was obtained.

(Pigment dispersion preparation example 3): Black pigment dispersion 3
Similar to Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed from 40 parts by mass to 10 parts by mass and distilled water was changed from 800 parts by mass to 830 parts by mass. Thus, a black pigment dispersion having a pigment concentration of 16% by mass was obtained.

(Pigment dispersion preparation example 4): Black pigment dispersion 4
Similar to Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed from 40 parts by mass to 20 parts by mass and distilled water was changed from 800 parts by mass to 820 parts by mass. Thus, a black pigment dispersion having a pigment concentration of 16% by mass was obtained.

(Pigment dispersion preparation example 5): Black pigment dispersion 5
Similar to Pigment Dispersion Preparation Example 1 except that the copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed from 40 parts by mass to 160 parts by mass and distilled water was changed from 800 parts by mass to 680 parts by mass. Thus, a black pigment dispersion having a pigment concentration of 16% by mass was obtained.

(Pigment dispersion preparation example 6): Black pigment dispersion 6
Same as Pigment Dispersion Preparation Example 1 except that copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed from 40 parts by mass to 200 parts by mass and distilled water was changed from 800 parts by mass to 640 parts by mass. Thus, a black pigment dispersion having a pigment concentration of 16% by mass was obtained.

(Pigment dispersion preparation example 7): Black pigment dispersion 7
Copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 is changed to a POE (m = 40) β-naphthyl ether (Takemoto Yushi Co., Ltd.) 10% aqueous solution, and its mass part is changed from 40 parts by mass to 400 parts by mass. A black pigment dispersion having a pigment concentration of 16% by mass was obtained in the same manner as in Pigment Dispersion Preparation Example 1 except that distilled water was changed from 800 parts by mass to 440 parts by mass.

(Pigment dispersion preparation example 8): Cyan pigment dispersion 1
The pigment concentration was 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1, except that the carbon black of Pigment Dispersion Preparation Example 1 was changed to Pigment Blue 15: 3 (Dainipei Seika Co., Ltd., Chromofine Blue). A blue pigment dispersion was obtained.

(Pigment Dispersion Preparation Example 9): Magenta pigment dispersion 1
Similar to Pigment Dispersion Preparation Example 1, except that the carbon black of Pigment Dispersion Preparation Example 1 was changed to Pigment Red 122 (manufactured by Clariant, Toner Magenta EO02). A pigment dispersion was obtained.

(Pigment dispersion preparation example 10): Yellow pigment dispersion 1
Yellow having a pigment concentration of 16% by mass in the same manner as in Pigment Dispersion Preparation Example 1, except that the carbon black of Pigment Dispersion Preparation Example 1 was changed to Pigment Yellow 74 (Daiichi Seika Chemical Co., Ltd., First Yellow 531). A pigment dispersion was obtained.

(Pigment Dispersion Preparation Example 11) to (Pigment Dispersion Preparation Example 33): Black Pigment Dispersion 8 to 30
Similar to Pigment Dispersion Preparation Example 1 except that Copolymer 1 (Synthesis Example 1) of Pigment Dispersion Preparation Example 1 was changed to Copolymer 3 (Synthesis Example 3) to Copolymer 25 (Synthesis Example 25). Thus, black pigment dispersions 11 to 33 having a pigment concentration of 16% by mass were obtained.

(Pigment dispersion preparation example 34): Cyan pigment dispersion 2
The carbon black of Pigment Dispersion Preparation Example 1 was changed to Pigment Blue 15: 3 (Dainipei Seika Co., Ltd., Chromofine Blue), and Copolymer 1 (Synthesis Example 1) was changed to Copolymer 24 (Synthesis Example 24). Except for the above, a blue pigment dispersion having a pigment concentration of 16% by mass was obtained in the same manner as in Pigment Dispersion Preparation Example 1.

(Pigment dispersion preparation example 35): Magenta pigment dispersion 2
Pigment Dispersion Example 1 except that the carbon black of Preparation 1 was changed to Pigment Red 122 (Clariant, Toner Magenta EO02), and Copolymer 1 (Synthesis Example 1) was changed to Copolymer 24 (Synthesis Example 24). In the same manner as in Dispersion Preparation Example 1, a red-violet pigment dispersion having a pigment concentration of 16% by mass was obtained.

(Pigment dispersion preparation example 36): Yellow pigment dispersion 2
Except for changing the carbon black of Pigment Dispersion Preparation Example 1 to Pigment Yellow 74 (Daiichi Seika Co., Ltd., First Yellow 531) and Copolymer 1 (Synthesis Example 1) to Copolymer 24 (Synthesis Example 24). In the same manner as in Pigment Dispersion Preparation Example 1, a yellow pigment dispersion having a pigment concentration of 16% by mass was obtained.

Table 2 summarizes the compositions of the pigment dispersions obtained in Pigment Dispersion Preparation Examples 1 to 36.

[Examples 1 to 32, Comparative Examples 1 to 6]
<Preparation of ink for ink jet recording>
The following tables show the configurations of the ink compositions of Examples 1 to 32 and Comparative Examples 1 to 6, respectively. In addition, the numerical value in a table | surface shows the mass%.

<Inkjet ink manufacturing method>
Example 1
The ingredients of the following formulation are mixed and stirred for 1 hour to mix uniformly. This dispersion was subjected to pressure filtration with a polyvinylidene fluoride membrane filter having an average pore size of 5.0 μm to remove coarse particles and dust, thereby producing a recording ink.
Pigment dispersion 1 of pigment dispersion preparation example 1 (pigment concentration 16%) 50.0 parts by mass

(Examples 2-32 and Comparative Examples 1-6)
For the inks of Examples 2-32 and Comparative Examples 1-6, inks were produced in the same manner as described above according to the following prescription table.

<Evaluation of storage stability of each pigment dispersion and each ink>
To measure the viscosity of pigment dispersion preparation examples 1-36, Examples 1-32, and Comparative Examples 1-6, and viscosity of each recording ink, a viscometer RE80L manufactured by Toki Sangyo Co., Ltd. was used. The viscosity at 25 ° C. was measured. About the rotation speed at the time of a viscosity measurement, it adjusted so that a torque might become fixed in 40%-80% of range. As an index of the dispersion stability of the pigment as the pigment dispersion and the ink, the initial viscosity after the preparation of the pigment dispersion and the ink was measured and evaluated based on the following criteria.
As for storage stability, after measuring the initial viscosity, each pigment dispersion and the ink are put in a polyethylene container, sealed, and measured after storage at 70 ° C. for 1 week, and the change from the initial viscosity is measured. The rate was evaluated based on the following criteria.

[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: Based on initial viscosity The change rate of the viscosity after storage was less than 5% B: The change rate of the viscosity after storage based on the initial viscosity was 5% or more and less than 50% C: The change rate of the viscosity after storage based on the initial viscosity was 50% or more

[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 · Preservability A: Based on initial viscosity The change rate of the viscosity after storage was less than 5% B: The change rate of the viscosity after storage based on the initial viscosity was 5% or more and less than 50% C: The change rate of the viscosity after storage based on the initial viscosity was 50% or more

<Print evaluation of each ink set>
Printing evaluation was performed on the recording inks of Examples 1 to 32 and Comparative Examples 1 to 6.
Using an ink jet printer (IPSiO GXe5500, manufactured by Ricoh Co., Ltd.), change the drive voltage of the piezo element so that the amount of ink discharged is uniform, and set the same amount of ink on the recording material. went.
The results are shown in the table.

<Image density &showthrough>
Using each ink, a chart containing general symbols of JIS X 0208 (1997), 2223 of 64 points created by Microsoft Word 2003 was printed on My Paper (manufactured by Ricoh), and then X-Rite 938 (X- The symbol portion was color-measured by Rite) to evaluate the image density. 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. JIS X 0208 (1997), 2223 is a symbol whose outer shape is a regular square and the entire surface of the symbol is filled with ink.
Also, using X-Rite 938, the image density of the symbol part and the non-printed part of the paper are measured from the back side of the paper, and the non-printed part of the paper is measured from the image density of the symbol part measured from the back side. The OD value obtained by subtracting the image density was used as the back-through density, and evaluation was performed according to the same criteria as 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 and less than 1.30
Yellow 0.75 or more and less than 0.80
Magenta 0.85 or more and 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 and less than 0.75
Magenta 0.75 or more and less than 0.85
Cyan 0.85 or more and 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]
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 and less than 0.20
Yellow 0.08 or more and less than 0.16
Magenta 0.09 or more and 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 and less than 0.40
Magenta 0.18 or more and less than 0.40
Cyan 0.20 or more and 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

101 apparatus main body 102 paper feed tray 103 paper discharge tray 104 ink storage container loading unit 105 operation unit 111 upper cover 112 front surface 115 front cover 131 guide rod 132 stay 133 carriage 134 recording head 135 sub tank 141 paper placement unit 142 paper 143 paper supply Roller 144 Separation pad 145 Guide 151 Conveying belt 152 Counter roller 153 Conveying guide 154 Pressing member 155 Tip pressure roller 156 Charging roller 157 Conveying roller 158 Tension roller 161 Guide member 171 Separating claw 172 Discharging roller 173 Discharging roller 181 Double-sided sheet feeding 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)

An ink for inkjet recording having a copolymer containing at least water, a water-soluble solvent, a pigment, and a phosphonic acid group, wherein the copolymer containing a phosphonic acid group is a structural unit represented by the following formula (1): An ink for inkjet recording, comprising at least a structural unit represented by the following formula (2) and / or the following formula (3).

(R ₁ in formula (1) represents hydrogen or a methyl group. M represents hydrogen, an alkali metal, or organic ammonium.)

An ink for inkjet recording having a copolymer containing at least water, a water-soluble solvent, a pigment, and a phosphonic acid group, wherein the copolymer containing the phosphonic acid group is represented by the following formula (4): An inkjet recording ink synthesized using at least a monomer represented by the following formula (5) and / or the following formula (6) as a starting material.

(R ₂ in formula (4) represents hydrogen or a methyl group.)

  The content of the structural unit of the formula (1) or the content of the monomer represented by the formula (4) in the copolymer containing the phosphonic acid group is 10% by mass to 60% by mass. The ink for inkjet recording according to claim 1 or 2.   The viscosity of the aqueous solution or aqueous dispersion having a solid content of 10% by mass of the phosphonic acid group-containing copolymer is 1.5 to 30.0 mPa · s. Ink jet recording ink.   5. An aqueous dispersion of a pigment composed of at least a pigment, water, and a copolymer containing the phosphonic acid group and a water-soluble solvent are mixed at least. The ink for inkjet recording as described.   6. The ink jet recording according to claim 5, wherein a mass ratio of the pigment and the copolymer containing a phosphonic acid group in the aqueous dispersion of the pigment is pigment / copolymer = 100/10 to 100/100. For ink.   7. The ink for ink jet recording according to claim 1, wherein M in the formula (1) constituting the copolymer is hydrogen, potassium or sodium.   8. The ink for ink jet recording according to claim 1, wherein a ratio of hydrogen to a total number of M in the formula (1) constituting the copolymer is 0% to 40%.   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 including an ink storage portion for storing ink, wherein the ink stored in the ink storage portion is the ink for ink jet recording according to any one of claims 1 to 9. Ink container.   An ink jet recording apparatus for recording information or an image on a recording medium using an ink jet head, wherein the ink is the ink for ink jet recording according to any one of claims 1 to 9. Recording device.   A method for producing a recorded matter comprising a step of recording on a recording medium by discharging ink from an ink jet head, wherein the ink is the ink for ink jet recording according to any one of claims 1 to 9. A method for producing recorded material.   A recorded matter in which information or an image is recorded on a recording medium using ink, wherein the ink is the ink for inkjet recording according to any one of claims 1 to 9.

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