JP2017145285A - Ink and its production method, and ink container, image forming method, image forming device, and image formation product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink which has high storage stability and provides high image density even in the case of recording on plain paper, in an inkjet recording system or the like.SOLUTION: The ink contains water, a color material, and a copolymer, where the copolymer comprises a structural unit represented by general formula (1) and a structural unit including a polyalkylene glycol ether in a side chain. (Ris H or a methyl group; X is a C2-4 alkylene group; and Y is a C5-7 alkylene group or a C6-13 alicyclic hydrocarbon divalent group.)SELECTED DRAWING: None

Description

  The present invention relates to an ink and a manufacturing method thereof, an ink container, an image forming method, an image forming apparatus, and an image formed product.

  The inkjet recording method is popular because it has the advantage that the process is simple and full color can be easily achieved compared to other recording methods, and a high-resolution image can be obtained even with an apparatus with a simple configuration. It is expanding from personal to office use, commercial printing and industrial printing. In such an ink jet recording method, a water-based ink composition using a water-soluble dye as a coloring material is mainly used. However, since it has a disadvantage of being inferior in water resistance and light resistance, it is a water-insoluble alternative to a water-soluble dye. Development of pigment inks using these pigments is underway.

  In inkjet printing for office use, plain paper is mainly used as a recording medium, and high image density is required. In general, when pigment ink is printed on plain paper, the pigment penetrates into the paper without staying on the paper surface, so the pigment density on the paper surface is lowered and the image density is lowered. If the pigment concentration in the ink is increased, the image density is increased, but the viscosity of the ink is increased and the ejection stability is lowered.

  In the field of commercial printing and industrial printing, there is a need for a technique for stably creating an image with higher resolution and sharpness at a higher speed. As the recording medium, plain paper, coated paper, art paper, non-permeable film such as PET film, and the like are used, and high adaptability of the ink to the recording medium is required. Therefore, in order to prevent paper curl that occurs when printing on plain paper in inkjet recording systems, or when printing on coated paper or art paper, it increases the ink permeability, speeds drying, and beads. In order to prevent this, there is a method of adding a hydrophilic organic solvent to the water-based ink.

  In addition, the aqueous pigment ink used in the ink jet recording method and writing instrument is different from the aqueous dye ink prepared by dissolving the dye in water, because it is necessary to stably disperse the pigment insoluble in water for a long period of time. Various pigment dispersants have been developed. For example, a graft polymer containing an aromatic ring in the side chain has been proposed (see, for example, Patent Document 1).

  An object of the present invention is to provide an ink having a high image density and high storage stability even when recorded on plain paper.

The ink of the present invention as a means for solving the problems is an ink containing water, a coloring material, and a copolymer,
The copolymer includes a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
However, the general formula (1), R ₁ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, Y is an alkylene group of 5-7 carbon atoms, or carbon This represents a divalent group of an alicyclic hydrocarbon of formula 6-13.
However, In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl group, n represents an integer of. 1 to 90, m is an integer of 0-90.

  According to the present invention, a high image density can be obtained even when recording on plain paper, and an ink having high storage stability can be provided.

FIG. 1 is an explanatory perspective view illustrating an example of an image forming apparatus. FIG. 2 is an explanatory perspective view illustrating an example of a main tank in the image forming apparatus.

(ink)
The ink of the present invention contains water, a coloring material, and a copolymer containing a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and further if necessary. And other ingredients.
The ink of the present invention is based on the knowledge that long-term storage stability is insufficient when a conventional graft polymer is used as a pigment dispersant.

<Copolymer>
The copolymer includes a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and further includes other structural units as necessary.
However, the general formula (1), R ₁ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, Y is an alkylene group of 5-7 carbon atoms, or carbon This represents a divalent group of an alicyclic hydrocarbon of formula 6-13.
The alkylene group having 5 to 7 carbon atoms of Y may be independently substituted with a methyl group, a methoxycarbonyl group, a halogen atom and a functional group containing a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

In the general formula (2), R ₂ and R ₃ represent a hydrogen atom or a methyl group.
In the above general formula (2), n and m represents an average addition mole number of ethylene oxide _{(C 2 H} 4 O) and propylene oxide _{(C 3 H} 6 O). n represents an integer of 1 to 90, m represents an integer of 0 to 90, and n is preferably 4 to 50, m is preferably 0, n is 8 to 30, and m is 8 to 30 from the viewpoint of ink storage stability and image density. 0 is more preferable.

The structural unit represented by the general formula (2) is preferably a structural unit represented by the following general formula (2 ′).
However, in the general formula ₍₂ '), _R 2 and _{R 3} represents a hydrogen atom or a methyl group, n represents an integer of 1 to 90.

  In the structural unit represented by the general formula (1), one end of the naphthyl group present at the end of the open end (open end, that is, the pendant structure) is defined as a colorant in the ink. Excellent pigment adsorbing power due to π-π stacking.

Specific examples of the structural unit represented by the general formula (1) are given below, but the present invention is not limited to the following specific examples.

As understood from the description of the “naphthyl group present at the end of the pendant structure”, the structural unit represented by the general formula (1) typically has a pendant group such as a terminal naphthyl group. It may be the main chain of the copolymer. However, as a matter of course, the case where a part is included in the side chain is not excluded.
For example, it is a well-known fact that it is difficult to completely eliminate secondary radical polymerization reactions that produce branched structures.
Further, when preparing the pigment dispersion in which the pigment is dispersed in water, if the copolymer used in the present invention is used, a naphthyl group is present at the end of the side chain of the copolymer, so that the pigment surface Since it is easily adsorbed and has a high adsorbing power with the pigment, a highly dispersible long-term stable pigment dispersion can be obtained.

  The content of the structural unit represented by the general formula (1) is not particularly limited and may be appropriately selected depending on the intended purpose, but is 30% by mass or more and 80% by mass with respect to the total amount of the copolymer. % Or less is preferable, and 40 mass% or more and 70 mass% or less are more preferable. When the content is within a preferable range, it is advantageous in that the image density and storage stability are improved when used in ink.

  The structural unit represented by the general formula (2) and cellulose mainly constituting plain paper are hydrophilic. Therefore, the structure represented by the general formula (2) is considered to have an affinity for cellulose rather than a hydrophobic solvent. When the copolymer is used in ink, the copolymer adsorbed on the pigment during printing is adsorbed on cellulose, and the pigment tends to stay on the paper surface. In the said General formula (2), it has a polyethyleneglycol chain and a polypropyleneglycol chain (n is an integer of 1-90, m is an integer of 0-90), it becomes easy to contact with a cellulose and it is easy to adsorb | suck to a cellulose more. It is considered to be. Thereby, a high image density can be shown even on plain paper.

  The content of the structural unit represented by the general formula (2) is not particularly limited and may be appropriately selected depending on the intended purpose, but is 20% by mass or more and 70% by mass with respect to the total amount of the copolymer. The following is preferable, and 30 mass% or more and 60 mass% or less are more preferable. When the content is within a preferable range, it is advantageous in that the image density and storage stability are improved when used in ink.

The copolymer may have a repeating unit derived from another polymerizable monomer in addition to the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2).
The other polymerizable monomer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a polymerizable hydrophobic monomer, a polymerizable hydrophilic monomer, and a polymerizable surfactant. .

  Examples of the polymerizable hydrophobic monomer include unsaturated ethylene monomers having an aromatic ring such as α-methylstyrene, 4-t-butylstyrene, 4-chloromethylstyrene; methyl (meth) acrylate, (meta ) Ethyl acrylate, (n-butyl) (meth) acrylate, dimethyl maleate, dimethyl itaconate, dimethyl fumarate, lauryl (meth) acrylate (C12), tridecyl (meth) acrylate (C13), (meth) Tetradecyl acrylate (C14), pentadecyl (meth) acrylate (C15), hexadecyl (meth) acrylate (C16), heptadecyl (meth) acrylate (C17), nonadecyl (meth) acrylate (C19), (meth) Eicosyl acrylate (C20), helicosyl (meth) acrylate (C21), Alkyl (meth) acrylates such as docosyl methacrylate (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, -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 And unsaturated ethylene monomers having an alkyl group such as 1-nonadecene, 1-eicosene and 1-docosene. These may be used individually by 1 type and may use 2 or more types together.

Examples of the polymerizable hydrophilic monomer include maleic acid or a salt thereof, monomethyl maleate, itaconic acid, monomethyl itaconic acid, fumaric acid, 4-styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, or Anionic unsaturated ethylene monomers such as unsaturated ethylene monomers containing phosphoric acid, phosphonic acid, alendronic acid or etidronic acid; (meth) acrylic acid-2-hydroxyethyl, diethylene glycol mono (meth) acrylate, triethylene glycol mono (Meth) acrylate, tetraethylene glycol mono (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, acrylamide, , N- dimethylacrylamide, N-t-butylacrylamide, N- octyl acrylamide, such as a non-ionic ethylenically unsaturated monomer such as N-t-octyl acrylamide.
The polymerizable hydrophobic monomer and the polymerizable hydrophilic monomer can be used alone or in combination of two or more.
The content of the polymerizable hydrophobic monomer and the polymerizable hydrophilic monomer is a monomer that forms the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2). 5 mass% or more and 100 mass% or less are preferable with respect to the total amount.

The polymerizable surfactant is an anionic or nonionic surfactant having at least one unsaturated double bondable group in the molecule.
Examples of the anionic surfactant, ammonium sulfate base ^_(-SO 3 - _NH ^{4 +)} hydrocarbon compound having a sulfate group and an allyl group _{(-CH 2} -CH = CH 2), such as, ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ sulfate group and methacrylic group, such as _{[-CO-C (CH 3) =} CH 2 ] a hydrocarbon compound having, or ammonium sulfate base ^_(-SO 3 - _NH ^{4 +)} sulfate, such as base and 1 An aromatic hydrocarbon compound having a —propenyl group (—CH═CH ₂ CH ₃ ) is exemplified. Examples of the anionic surfactant include Eleminol JS-20 and RS-300 manufactured by Sanyo Chemical Industries, Ltd., Aqualon KH-10, Aqualon KH-1025, Aqualon KH-05 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. , Aqualon HS-10, Aqualon HS-1025, Aqualon BC-0515, Aqualon BC-10, Aqualon BC-1025, Aqualon BC-20, Aqualon BC-2020 and the like.

Examples of the nonionic surfactant include a hydrocarbon compound having a 1-propenyl group (—CH═CH ₂ CH ₃ ) and a polyoxyethylene group [— (C ₂ H ₄ O) n—H], or An aromatic hydrocarbon compound etc. are mentioned. Specific examples of the nonionic surfactant include Aqualon RN-20, Aqualon RN-2025, Aqualon RN-30, and Aqualon RN-50 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. 104, Latem PD-420, Latem PD-430, Latem PD-450, and the like.

The said polymerizable surfactant can be used 1 type or in mixture of 2 or more types.
The content of the polymerizable surfactant is 0. 0 relative to the total amount of the monomers forming the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2). 1 mass% or more and 10 mass% or less are preferable.

  The weight average molecular weight of the copolymer is preferably 5,000 to 50,000, more preferably 15,000 to 40,000 in terms of polystyrene. When the weight average molecular weight is within a preferred range, it is advantageous in that the image density and storage stability are good when used in ink.

The structure of the copolymer can be analyzed by using a general analytical method such as NMR or IR.
The molar ratio of the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) constituting the copolymer is the monomer used when the copolymer is synthesized. The molar ratio can be determined. Moreover, it can obtain | require by NMR from a copolymer.

<Synthesis Method of Copolymer>
The copolymer used in the present invention is not particularly limited, and can be synthesized by various polymerization methods, for example, known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. it can. The polymerization reaction can be performed by a known operation such as a batch system, a semi-continuous system, or a continuous system. Although not limited to these polymerization methods, radical polymerization using the radical polymerization initiator shown below is preferable because the polymerization operation and the adjustment of molecular weight are easy, and a solution polymerization method in which polymerization is performed in a mixed solvent of an organic solvent and water is used. Further preferred.

The copolymer containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) in the present invention includes a monomer represented by the following general formula (3) and the following general formula: It can be synthesized by radical polymerization from a polymerizable material (starting material) containing the monomer represented by (4).
However, In the general formula (3), R ₄ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, Y represents an alkylene group having 5-7 carbon atoms or 6 carbon atoms It represents a divalent group of alicyclic hydrocarbon of ~ 13.

In the general formula (4), _{R 5} and _{R 6} represent a hydrogen atom or a methyl group, n represents an integer of. 1 to 90, m is an integer of 0-90.

Specific examples of the compound represented by the general formula (3) are given below, but the present invention is not limited to the following specific examples.

  The monomer represented by the general formula (3) can be synthesized as follows. That is, as shown in the following reaction formulas (1) to (2), first, the diisocyanate compound (A-1) and naphthol (A-2) are reacted in the presence of an acid acceptor such as amine or pyridine. To obtain a reaction intermediate (A-3). Next, the monomer represented by the general formula (3) can be obtained by reacting the hydroxyalkyl methacrylate (A-4) with the (A-3).

<Reaction Formula (1)>
However, in the reaction formula (1), Y represents the same meaning as in the general formula (3).

<Reaction Formula (2)>
However, in the reaction formula (2), Y and X represent the same meaning as in the general formula (3). R represents the same meaning as R _{5 in the} general formula (4).

  As another method, the above (A-1) and the above (A-4) are reacted first and then reacted with the above (A-2) to represent the above general formula (3). A compound can be obtained.

  As another method, as shown in the following reaction formula (3), by reacting the diisocyanate compound (A-1), naphthol (A-2), and hydroxyalkyl methacrylate (A-4), A monomer represented by the formula (3) can also be obtained.

<Reaction Formula 3>
However, in the reaction formula (2), Y and X represent the same meaning as in the general formula (3). R represents the same meaning as R _{5 in the} general formula (4).

  As the monomer represented by the general formula (4), an appropriately synthesized monomer or a commercially available product may be used. Examples of the commercially available products include Bremer PE-90, PE-200, PE-350, AE-90U, AE-200, AE-400, PME-100, PME-200, PME-400, PME-1000, and PME. -4000, AME-200, AME-400 (all manufactured by NOF Corporation) and the like.

As the method for synthesizing the copolymer, a method using a radical polymerization initiator is preferable because the polymerization operation and the molecular weight are easily adjusted, and a solution polymerization method in which a polymerization reaction is performed in a solution is more preferable.
Preferred solvents for radical polymerization by the solution polymerization method include ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, acetate solvents such as ethyl acetate and butyl acetate, and aromatic solvents such as benzene, toluene and xylene. Examples thereof include hydrocarbon solvents, isopropanol, ethanol, cyclohexane, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoamide and the like. Among these, ketone solvents, acetate ester 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. Is mentioned. Among these, organic peroxides and azo compounds are preferable, and azo compounds are particularly preferable because the molecular weight is easily controlled and the decomposition temperature is low.

  The content of the radical polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1% by mass or more and 10% by mass or less with respect to the total amount of polymerizable monomers.

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 about 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. There is no restriction | limiting in particular about superposition | polymerization time, Although it can select suitably according to the objective, 3 hours or more and 48 hours or less are preferable.

The copolymer used in the present invention is not particularly limited, and can be used as a pigment dispersant or an additive to the pigment dispersion. When used as a pigment dispersant, further improvement in storage stability in inks having a high water-soluble organic solvent content is observed.
The content of the copolymer used in the present invention is not particularly limited when used as a pigment dispersant, and can be appropriately selected according to the purpose, but with respect to 100 parts by mass of the pigment, 1 part by mass or more and 100 parts by mass or less is preferable, and 5 parts by mass or more and 80 parts by mass or less are more preferable. When the content is within the more preferable range, it is advantageous in that image density and storage stability are improved. Moreover, you may use another dispersing agent together in the range which does not impair the effect as a dispersing agent of a copolymer.

The content of the copolymer is not particularly limited and may be appropriately selected according to the purpose. However, the solid content is preferably 0.05% by mass or more and 10% by mass or less based on the total amount of the ink, 0.3 mass% or more and 5 mass% or less are more preferable.
When the content is 0.05% by mass or more, an effect of improving dispersibility and storage stability is recognized, and when the content is 10% by mass or less, it is possible to make the viscosity range suitable for ejecting ink from the head. Become.

<Water>
As said water, pure water, such as ion-exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used, for example.
The content of the water in the ink is not particularly limited and may be appropriately selected according to the purpose. However, from the viewpoint of ink drying property and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, 20 mass% or more and 60 mass% or less are more preferable.

<Color material>
As the color material, a pigment or a dye can be used. The pigment is preferable from the viewpoints of the pigment being superior to the dye in terms of the ability of the copolymer to adsorb to the coloring material, and water resistance and light resistance.

  There is no restriction | limiting in particular as said pigment, According to the objective, it can select suitably, For example, the inorganic pigment, organic pigment, etc. for black or color are mentioned. These may be used alone or in combination of two or more.

Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as a known method such as a contact method, a furnace method, and a thermal method. Carbon black can be used.
Examples of black pigments include, for example, carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, and metals such as copper and iron (CI pigment black 11). And metal oxides such as titanium oxide and organic pigments such as aniline black (CI Pigment Black 1).
The carbon black is a carbon black produced by a furnace method or a channel method, a primary particle size of 15 nm to 40 nm, a specific surface area by a BET method of 50 m ² / g to 300 m ² / g, and a DBP oil absorption of 40 mL. / 100 g to 150 mL / 100 g, those having a volatile content of 0.5% to 10% and a pH of 2 to 9 are preferred.

Examples of the organic pigment include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, Dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelate, acid dye chelate, etc.), nitro pigments, nitroso pigments, aniline black, and the like can be used.
Of these pigments, those having a good affinity for water are particularly preferably used.

Examples of the azo pigments include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments.
Examples of the polycyclic pigment include a phthalocyanine pigment, a perylene pigment, a perinone pigment, an anthraquinone pigment, a quinacridone pigment, a dioxazine pigment, an indigo pigment, a thioindigo pigment, an isoindolinone pigment, a quinofullerone pigment, and a rhodamine B lake pigment. .
Examples of the dye chelate include basic dye chelate and acid dye chelate.

  There is no restriction | limiting in particular as a pigment for yellow, According to the objective, it can select suitably, For example, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. And CI Pigment Yellow 180.

  The magenta pigment 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 for cyan is not particularly limited and may be appropriately selected depending on the intended 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. Examples include Bat Blue 60.

  In addition, C.I. I. Pigment Yellow 74, C.I. I. Pigment red 122, C.I. I. Pigment Bio Red 19 and C.I. I. By using CI Pigment Blue 15: 3, a well-balanced ink having excellent color tone and light resistance can be obtained.

For the ink of the present invention, a color material newly produced for the present invention can also be used.
Further, from the viewpoint of color developability of the obtained image, a self-dispersing pigment may be used, and an anionic self-dispersing pigment is preferable. The anionic self-dispersing pigment refers to a pigment that is dispersed and stabilized by introducing an anionic functional group directly on the pigment surface or via another atomic group.
As the pigment before dispersion stabilization, for example, various conventionally known pigments as listed in International Publication No. 2009/014242 can be used.
In addition, an anionic functional group means the functional group which half or more of hydrogen ions dissociate at pH 7.0. Specific examples of the anionic functional group include a carboxyl group, a sulfo group, and a phosphonic acid group. Among these, a carboxyl group or a phosphonic acid group is preferable from the viewpoint of increasing the optical density of the obtained image.
Examples of the method for introducing an anionic functional group into the surface of the pigment include a method for oxidizing carbon black.
Specific examples of the oxidation treatment method include a method of treating with hypochlorite, ozone water, hydrogen peroxide, chlorite, nitric acid, etc., Patent No. 3808504, Special Table 2009-515007, And a surface treatment method using a diazonium salt as described in JP-A-2009-506196.
Examples of commercially available pigments having a hydrophilic functional group introduced on the surface include CW-1, CW-2, and CW-3 (above, manufactured by Orient Chemical Industry Co., Ltd.); CAB-O-JET200, CAB- O-JET300, CAB-O-JET400 (manufactured by Cabot Corporation) and the like can be mentioned.

  The content of the pigment in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.5% by mass or more and 20% by mass or less, and more preferably 1% by mass or more and 10% by mass or less. More preferred.

As the dye, dyes classified in the color index into acid dyes, direct dyes, basic dyes, reactive dyes, and food dyes can be used.
Examples of the acid dyes and food dyes include C.I. I. Acid Black 1, 2, 7, 24, 26, 94, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Blue 9, 29, 45, 92, 249, C.I. I. Acid Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97, 106, 111, 114, 115, 134, 186, 249, 254, 289, C.I. I. Food Black 1, 2, C.I. I. Food Yellow 3, 4, C.I. I. Food red 7, 9, 14 etc. are mentioned.
Examples of the direct dye include C.I. I. Direct Black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, (168), 171, C.I. I. Direct Yellow 1, 12, 24, 26, 33, 44, 50, 86, 120, 132, 142, 144, C.I. I. Direct Blue 1, 2, 6, 15, 22, 25, 71, 76, 79, 86, 87, 90, 98, 163, 165, 199, 202, C.I. I. Direct Red 1, 4, 9, 13, 17, 20, 28, 31, 39, 80, 81, 83, 89, 225, 227, C.I. I. Direct orange 26, 29, 62, 102 etc. are mentioned.
Examples of the basic dye include C.I. I. Basic Black 2, 8, C.I. I. Basic yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41, 45, 49, 51, 53, 63, 64, 65, 67, 70, 73, 77, 87, 91, C.I. I. Basic Blue 1, 3, 5, 7, 9, 21, 22, 26, 35, 41, 45, 47, 54, 62, 65, 66, 67, 69, 75, 77, 78, 89, 92, 93, 105, 117, 120, 122, 124, 129, 137, 141, 147, 155, C.I. I. Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46, 49, 51, 52, 54, 59, 68, 69, 70, 73, 78, 82, 102, 104, 109, 112 and the like.
Examples of the reactive dye include C.I. I. Reactive Black 3, 4, 7, 11, 12, 17, C.I. I. Reactive Yellow 1, 5, 11, 13, 14, 20, 21, 22, 25, 40, 47, 51, 55, 65, 67, C.I. I. Reactive Blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95, C.I. I. Reactive Red 1, 14, 17, 25, 26, 32, 37, 44, 46, 55, 60, 66, 74, 79, 96, 97, etc. are mentioned.

  The ink of the present invention is an organic solvent for increasing the permeability to plain paper, coated paper, etc., further suppressing the occurrence of beading, and for preventing the ink from drying by utilizing the wetting effect. It is preferable to contain.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-he Polyhydric alcohols such as sundiol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, ethylene glycol mono Polyhydric alcohol alkyl ethers such as ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether, ethylene glycol mono Polyhydric alcohol aryl ethers such as benzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- -N-containing heterocyclic compounds such as pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, Amides such as N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, Examples include ethylene carbonate.
In addition to functioning as a wetting agent, it is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because good drying properties can be obtained.

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

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

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of the drying property and ejection reliability of the ink, 20 mass% or more and 60 mass% or less are more preferable.

  The ink of the present invention preferably contains a surfactant in order to enhance the permeability and wettability to plain paper or coated paper and further suppress the occurrence of beading.

<Surfactant>
As the surfactant, any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants and anionic surfactants can be used.
There is no restriction | limiting in particular in silicone type surfactant, According to the objective, it can select suitably. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, and side chain both terminal modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as an aqueous surfactant. In addition, as the silicone surfactant, a polyether-modified silicone surfactant can be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.
Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylate. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.
Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like. These may be used alone or in combination of two or more.

The silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side Since both ends of the chain are modified with polydimethylsiloxane, a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibits good properties as an aqueous surfactant. preferable.
As such a surfactant, an appropriately synthesized product or a commercially available product may be used. Commercially available products can be obtained from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.
There is no restriction | limiting in particular as said polyether modified silicone surfactant, According to the objective, it can select suitably, For example, the polyalkylene oxide structure represented by a general formula (S-1) type | formula is dimethylpolyethylene. Examples thereof include those introduced into the side chain of Si part of siloxane.
[General Formula (S-1)]
(In the general formula (S-1), m, n, a, and b represent integers. R and R ′ represent an alkyl group and an alkylene group.)
A commercial item can be used as said polyether modified silicone type surfactant, For example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Bic Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of the fluorosurfactant include perfluoroalkyl phosphate compounds, perfluoroalkylethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain.
Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because of its low foaming property, and in particular, fluorine-based compounds represented by the general formulas (F-1) and (F-2) A surfactant is preferred.
[General Formula (F-1)]
In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
[General Formula (F-2)]
_{C n F 2n + 1- CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y
In the compound represented by the general formula (F-2), Y is H, or CnF _{2n + 1} , n is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ —CnF _{2n + 1,} where n is 4 to 6. An integer, or CpH _{2p + 1} , p is an integer of 1-19. a is an integer of 4-14.
A commercial item may be used as said fluorosurfactant.
As this commercial item, for example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F -1405, F-474 (all manufactured by DIC Corporation); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont) ); FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Refox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omninova), Unidyne DSN-403N (manufactured by Daikin Kogyo Co., Ltd.), etc., among these, good printing PF-300 manufactured by DuPont, FT-110 manufactured by Neos, FT-250, FT-251, FT -400S, FT-150, FT-400SW, Polynova PF-151N manufactured by Omninova, and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferable.

  There is no restriction | limiting in particular as content of surfactant in an ink, Although it can select suitably according to the objective, From the point which is excellent in wettability and discharge stability, and image quality improves, it is 0.001 mass. % To 5% by mass is preferable, and 0.05% to 5% by mass is more preferable.

  The ink of the present invention preferably contains, for example, an antiseptic / antifungal agent, a rust inhibitor, a pH adjuster and the like as the other components as necessary.

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

<Rust preventive>
There is no restriction | limiting in particular as a rust preventive agent, For example, acidic sulfite, sodium thiosulfate, etc. are mentioned.

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

There is no restriction | limiting in particular as a physical property of an ink, According to the objective, it can select suitably, For example, it is preferable that a viscosity, surface tension, pH, etc. are the following ranges.
The viscosity at 25 ° C. of the ink is preferably 5 mPa · s or more and 30 mPa · s or less, preferably 5 mPa · s or more and 25 mPa · s or less from the viewpoint of improving the printing density and character quality and obtaining good discharge properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. Measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid amount 1.2 mL, rotation speed 50 rpm, and measurement is possible for 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less and more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is suitably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12 and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

(Ink production method)
The method for producing an ink of the present invention is a method for producing an ink containing water, a color material, and a copolymer, which includes a copolymer synthesis step, and further includes other steps as necessary.
The step of synthesizing the copolymer is the same as the method for synthesizing the copolymer.

As said other process, a mixing process etc. are mentioned, for example.
The mixing step is a step of dispersing or dissolving the water, the coloring material, the copolymer, and the other components and stirring and mixing them.
The copolymer may be used as a pigment dispersion resin when preparing a pigment dispersion.
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, or ultrasonic dispersion. The stirring and mixing can be performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser or the like.

<Recording medium>
The recording medium used for recording is not particularly limited, and examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper.

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

(Ink container)
The ink container of the present invention is an ink container having an ink container that stores ink, and the ink stored in the ink container is the ink of the present invention. The ink is contained in a container, and further includes other members appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, at least an ink container formed of an aluminum laminate film, a resin film, etc. What has is suitable.

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

  The method of using the ink is not limited to the ink jet recording method, and can be widely used. Besides the ink jet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be applied to printed materials, paints, coating materials, foundations and the like. Furthermore, it can be used not only to form two-dimensional characters and images using ink, but also as a three-dimensional modeling material for forming a three-dimensional three-dimensional image (three-dimensional modeled object).
A known three-dimensional modeling apparatus for modeling a three-dimensional model can be used, and is not particularly limited. For example, a three-dimensional modeling apparatus including an ink storage unit, a supply unit, a discharge unit, a drying unit, or the like is used. be able to. The three-dimensional structure includes a three-dimensional structure obtained by repeatedly applying ink. Further, a molded product obtained by processing a structure provided with ink on a substrate such as a recording medium is also included. The molded product is obtained by subjecting a recorded material or a structure formed in a sheet shape or a film shape to a molding process such as heat stretching or punching, for example, an automobile, an OA device, an electric -It is suitably used for applications in which surfaces are decorated after decorating, such as meters for electronic devices, cameras, etc., and panels for operation units.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Moreover, the average molecular weight of the copolymer used by the Example and the comparative example was calculated | required as follows.

<Measurement of average molecular weight of copolymer>
The measurement was carried out under the following conditions by GPC (Gel Permeation Chromatography).
・ Device: GPC-8020 (manufactured by Tosoh Corporation)
Column: TSK G2000HXL and G4000HXL (manufactured by Tosoh Corporation)
・ Temperature: 40 ℃
・ Solvent: THF (tetrahydrofuran)
-Flow rate: 1.0 mL / min 1 mL of a copolymer having a concentration of 0.5% by mass was injected, and a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from the molecular weight distribution of the copolymer measured under the above conditions was used. The number average molecular weight Mn and the weight average molecular weight Mw of the copolymer were calculated.

(Monomer Synthesis Example 1)
-Synthesis of monomer M-3-
50.5 g (300 mmol) of hexamethylene diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 30.4 g (300 mmol) of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in 300 mL of dry toluene, And heated to 105 ° C. with stirring. A solution prepared by dissolving 43.3 g (300 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) in 1,500 mL of dry toluene was slowly added dropwise thereto. After dropping, the mixture was stirred at 105 ° C. for 2 hours. After cooling to room temperature, the precipitate was filtered off and the filtrate was collected.
The solvent was distilled off from the filtrate to obtain a white solid. 200 mL of hexane was added thereto and stirred at room temperature for 1 hour. The white solid was filtered off to obtain 53.0 g of a reaction intermediate of the following structural formula (1).

  20.8 g (160 mmol) of 2-hydroxyethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 80 mL of methyl ethyl ketone and stirred at room temperature under an argon stream. 0.03 g of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise thereto and heated to 50 ° C. with stirring. A solution prepared by dissolving 50.0 g of the reaction intermediate of the structural formula (1) in 120 ml of methyl ethyl ketone was slowly added dropwise thereto. After dropping, the mixture was stirred at 50 ° C. for 2 hours. After cooling to room temperature, insoluble matters were filtered off, and the solvent was distilled off from the filtrate to obtain a pasty crude product. This was purified by silica gel column chromatography (methylene chloride / ethyl acetate = 6/1) to obtain 48.0 g of monomer M-3 as a target product.

(Monomer synthesis example 2)
-Synthesis of Monomer M-8-
Dissolve 91.0 g (347 mmol) of dicyclohexylmethane 4,4′-diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 35.1 g (347 mmol) of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) in 200 mL of dry toluene. And heated to 105 ° C. with stirring under an argon stream. A solution prepared by dissolving 42.5 g (295 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) in 800 mL of dry toluene was slowly added dropwise thereto. After dropping, the mixture was stirred at 105 ° C. for 2 hours. After cooling to room temperature, the precipitate was filtered off and the filtrate was collected.
The solvent was distilled off from the filtrate to obtain a white solid. 200 mL of hexane was added thereto and stirred at room temperature for 1 hour. The white solid was filtered off to obtain 55.0 g of a reaction intermediate of the following structural formula (1 ′).

  16.6 g (143 mmol) of 2-hydroxyethyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 80 mL of methyl ethyl ketone and stirred at room temperature under an argon stream. 0.2 g of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise thereto and heated to 60 ° C. with stirring. A solution prepared by dissolving 52.0 g of the reaction intermediate of the structural formula (1 ′) in a mixed solution of 26 mL of methyl ethyl ketone and 16 mL of tetrahydrofuran was slowly added dropwise thereto. After dropping, the mixture was stirred at 60 ° C. for 2 hours. After cooling to room temperature, insoluble matters were filtered off, and the solvent was distilled off from the filtrate to obtain a pasty crude product. This was purified by silica gel chromatography (toluene / ethyl acetate = 5/1) to obtain 52.0 g of monomer M-8 as a target product.

(Monomer Synthesis Example 3)
-Synthesis of a mixture of monomer M-10 and monomer M-11-
91.0 g (409 mmol) of isophorone diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.), 35.1 g (347 mmol) of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 200 g of toluene were placed in a reaction vessel and stirred under a nitrogen stream. Dissolved.
This solution was heated to 105 ° C., and 42.5 g (295 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise with 800 g of toluene, followed by stirring at 105 ° C. for 2 hours for reaction. Was terminated. Then, the filtrate obtained by cooling to room temperature (25 ° C.) and removing the precipitate by filtration was concentrated to dryness, washed with hexane, and represented by 55 g of the following structural formulas (2) and (3). The resulting monoisocyanate intermediate was obtained.

  Next, 16.6 g (128 mmol) of 2-hydroxyethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 80 g of methyl ethyl ketone are placed in a reaction vessel, and 0.2 g of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) Was further dissolved by stirring. Next, this solution was heated to 60 ° C., and a mixed solution of 52 g of the monoisocyanate intermediate, 26 g of methyl ethyl ketone, and 15 g of tetrahydrofuran was added dropwise. Thereafter, the reaction was completed by stirring at 60 ° C. for 2 hours. Then, it cooled to room temperature, the filtrate obtained by removing an insoluble matter by filtration was concentrated to dryness, and the rough-yield of the mixture represented by 58 g of monomer M-10 and monomer M-11 was obtained. This was further purified by column chromatography on silica gel using a toluene / ethyl acetate mixed solvent as a developing solvent, to obtain a mixture of 52 g of monomer M-10 and monomer M-11 as the target product.

(Copolymer Synthesis Example 1)
-Synthesis of copolymer CP-1-
A monomer solution was prepared by dissolving 57.3 g (51.5 mmol) of methoxypolyethylene glycol methacrylate (manufactured by NOF Corporation) and 42.7 g (96.9 mmol) of monomer M-3 in 200 mL of dry methyl ethyl ketone. . After heating 10 mass% of the monomer solution to 75 ° C. under an argon stream, 3.70 g of 2,2′-azobis (isobutyronitrile) (AIBN, manufactured by Tokyo Chemical Industry Co., Ltd.), A solution in which 0.30 g of α-thioglycerol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved was dropped over 2.5 hours and stirred at 75 ° C. for 6 hours. After cooling to room temperature, the resulting reaction solution was dropped into hexane. The precipitated copolymer was filtered off and dried under reduced pressure to obtain 97.9 g of [Copolymer CP-1] (weight average molecular weight (Mw): 21,600).

(Synthesis Examples 2-19 of Copolymer)
-Synthesis of copolymers CP-2 to CP-19-
In the synthesis example 1 of the copolymer, the monomer represented by the general formula (3) and the general formula (4) is used in the content (parts by mass) shown in Table 1, and the content (mass by mass) shown in Table 2 Part) polymerization initiator (AIBN) and a chain transfer regulator (thioglycerol) were used in the same manner as in Synthesis Example 1 for copolymers to obtain [Copolymer CP-2 to 19]. . The IR spectra of the obtained copolymers CP-2 to CP-19 showed the same spectrum as that of the copolymer CP-1.
Next, the weight average molecular weights Mw of the obtained copolymers CP-2 to CP-19 are as shown in Table 2.

(Preparation Example 1 of Pigment Dispersion)
-Preparation of pigment dispersion PD-1-
To 40.0 parts by mass of the 10% by mass aqueous solution of copolymer CP-1, 16.0 parts by mass of carbon black (NIPEX 150, manufactured by Degussa) and 44.0 parts by mass of pure water were added and stirred for 12 hours. The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls having a diameter of 0.1 mm), and then the average pore size was measured. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 97.0 parts by mass of [Pigment Dispersion PD-1] (pigment solid content concentration: 16% by mass).

(Preparation Examples 2-24 of Pigment Dispersion)
-Preparation of Pigment Dispersion PD-2-24-
In Preparation Example 1 of Pigment Dispersion, except for using the copolymers CP-2 to 19 in the content (parts by mass) shown in Table 3 and using the pigment shown in Table 3, Preparation Example 1 of Pigment Dispersion and Similarly, pigment dispersions PD-2 to 24 were obtained.

In Table 3, the following products were used as pigments other than carbon black.
Pigment Blue 15: 3 (Chromo Fine Blue A-220JC, manufactured by Dainichi Seika Kogyo Co., Ltd.) Pigment Red 122 (Toner Magenta EO02, manufactured by Clariant)
・ Pigment Yellow 74 (First Yellow 531, manufactured by Dainichi Seika Kogyo Co., Ltd.)

Example 1
-Preparation of ink GJ-1-
40.0 parts by weight of Pigment Dispersion PD-1, 10.0 parts by weight of glycerin, 20.0 parts by weight of 1,3-butanediol, 10.0 parts by weight of 3-methoxy-N, N-dimethylpropion Amide, 1.0 part by weight of 2-ethyl-1,3-hexanediol, 1.0 part by weight of 2,2,4-trimethyl-1,3-pentanediol, 1.0 part by weight of Unidyne DSN-403N (Daikin Kogyo Co., Ltd.) and 17.0 parts by mass of ion-exchanged water were mixed and stirred for 1 hour, and then filtered through a membrane filter having an average pore size of 1.2 μm, so that the ink GJ-1 of Example 1 was used. Produced.

(Examples 2 to 24)
-Preparation of ink GJ-2 to 24-
Inks GJ-2 to 24 of Examples 2 to 24 were produced in the same manner as in Example 1 except that the ink formulations shown in Tables 4 and 5 were changed in Example 1.

(Comparative Example 1)
-Preparation of ink RGJ-1-
A monomer solution was prepared by dissolving 8.20 g of methoxypolyethylene glycol methacrylate (n≈23) and 7.03 g of the monomer represented by the following structural formula (6) in 30 mL of dry methyl ethyl ketone. After heating 10 mass% of the monomer solution to 75 ° C. under an argon stream, a solution obtained by dissolving 0.556 g of 2,2-azobis (isobutyronitrile) in the remaining monomer solution was added over 1.5 hours. The solution was added dropwise and stirred at 75 ° C. for 6 hours. After cooling to room temperature, the resulting reaction solution was poured into hexane. The precipitated copolymer was filtered off and dried under reduced pressure to obtain 14.11 g of a comparative copolymer RCP-1 (weight average molecular weight (Mw): 12,500).

Next, using this, a 10% by mass aqueous solution of comparative copolymer RCP-1 was prepared in the same manner as in Example 1.
Next, Example 1 and Example 1 were used except that a 10% by mass aqueous solution of comparative copolymer RCP-1 was used instead of the 10% by mass aqueous solution of copolymer CP-1 in the preparation of the pigment dispersion of Example 1. Similarly, a comparative pigment dispersion RPD-1 was obtained.
Next, a comparative ink RGJ-1 was obtained in the same manner as in Example 1 except that the comparative pigment dispersion RPD-1 was used instead of the pigment dispersion PD-1 in the preparation of the ink of Example 1. .

(Comparative Example 2)
-Preparation of ink RGJ-2-
In the same manner as in Example 22, except that a 10% by mass aqueous solution of the comparative copolymer RCP-1 was used instead of the 10% by mass aqueous solution of the copolymer CP-1 in the preparation of the pigment dispersion of Example 22. Comparative pigment dispersion RPD-2 was obtained.
Next, a comparative ink RGJ-2 was obtained in the same manner as in Example 22 except that the comparative pigment dispersion RPD-2 was used instead of the pigment dispersion PD-22 in the preparation of the ink of Example 22. .

(Comparative Example 3)
-Preparation of ink RGJ-3-
In the same manner as in Example 23, except that a 10% by mass aqueous solution of comparative copolymer RCP-1 was used instead of the 10% by mass aqueous solution of copolymer CP-1 in the preparation of the pigment dispersion of Example 23. Comparative pigment dispersion RPD-3 was obtained.
Next, a comparative ink RGJ-3 was obtained in the same manner as in Example 23 except that the comparative pigment dispersion RPD-3 was used instead of the pigment dispersion PD-23 in the preparation of the ink of Example 23. .

(Comparative Example 4)
-Preparation of ink RGJ-4-
In the same manner as in Example 24 except that a 10% by mass aqueous solution of comparative copolymer RCP-1 was used instead of the 10% by mass aqueous solution of copolymer CP-1 in the preparation of the pigment dispersion of Example 24. Comparative pigment dispersion RPD-4 was obtained.
Next, a comparative ink RGJ-4 was obtained in the same manner as in Example 24 except that the comparative pigment dispersion RPD-4 was used instead of the pigment dispersion PD-24 in the ink preparation of Example 24.

(Comparative Example 5)
-Preparation of ink RGJ-5-
80 g of 2-phenoxyethyl methacrylate as a monomer, 3.7 g of 3-mercapto-1-propanol as a chain transfer agent, and 0.3 g of 2,2-azobis (2,4-dimethylvaleronitrile) as an initiator in tetrahydrofuran (THF) It melt | dissolved in 160 mL, and it was made to react for 7 hours by heating at 65 degreeC by nitrogen atmosphere. The resulting solution was allowed to cool, 80 mg of dibutyltin dilaurate (IV) and a catalytic amount of hydroquinone were added, and 10.0 g of 2-methacryloyloxyethyl isocyanate was added dropwise. After raising the temperature to 50 ° C. and reacting for 2.5 hours, purification was performed by reprecipitation with a mixed solvent of methanol and water, and 71 g of macromonomer MM-1 (weight average molecular weight (Mw): 4,000, Number average molecular weight (Mn): 1,900) was obtained.
Next, after heating 20 g of methyl ethyl ketone to 75 ° C. under a nitrogen atmosphere, 1.16 g of dimethyl 2,2′-azobisisobutyrate, 9 g of the macromonomer MM-1 obtained above, 1.8 g P-styrenesulfonic acid and 49.2 g of methyl methacrylate dissolved in 40 g of methyl ethyl ketone were added dropwise over 3 hours. After completion of the dropwise addition, the reaction was further continued for 1 hour, and then a solution of 0.2 g of dimethyl 2,2′-azobisisobutyrate dissolved in 0.6 g of methyl ethyl ketone was added, the temperature was raised to 80 ° C., and the mixture was heated and stirred for 4 hours. did. Further, a solution of 0.2 g of dimethyl 2,2′-azobisisobutyrate dissolved in 0.6 g of methyl ethyl ketone was added, and the mixture was heated and stirred for 6 hours. After cooling, the resulting reaction solution was dropped into hexane, and the precipitated graft polymer was filtered off and dried to obtain a comparative copolymer RCP-2 (weight average molecular weight (Mw): 22,000). .

-Preparation of comparative pigment dispersion RPD-5-
Next, in the same manner as in Example 1 except that a 10% by mass aqueous solution of comparative copolymer RCP-2 was used instead of the 10% by mass aqueous solution of copolymer CP-1 in the preparation of the pigment dispersion of Example 1. As a result, a comparative pigment dispersion RPD-5 was obtained.
Next, comparative ink RGJ-5 was obtained in the same manner as in Example 1, except that Comparative Pigment Dispersion RPD-5 was used instead of Pigment Dispersion PD-1 in the preparation of the ink of Example 1. .

(Comparative Example 6)
<Preparation of Ink RGJ-6>
-Synthesis of comparative copolymer RCP-3-
72.0 g (500 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) and 125.0 g (1,000 mmol) of ethylene glycol mono-2-chloroethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) It melt | dissolved in N-methyl-2- pyrrolidinone (made by Kanto Chemical Co., Inc.), and stirred at room temperature for 1 hour. Furthermore, it stirred at 110 degreeC for 10 hours. After cooling to room temperature, 2,500 mL of pure water was added to the resulting reaction solution and stirred at room temperature for 1 hour. The precipitated solid was filtered off and dried under reduced pressure.
70.0 g of the solid obtained in the above reaction and 45.0 g (450 mmol) of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in 250 mL of tetrahydrofuran and stirred for 30 minutes in an ice bath. 36.6 g (350 mmol) of methacryloyl chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was slowly added dropwise thereto, and the mixture was further stirred for 3 hours in an ice bath. To the obtained solution, 250 mL of ethyl acetate and 100 mL of pure water were added and washed with water. Next, the ethyl acetate layer was isolated and washed with a saturated saline solution. The ethyl acetate layer was isolated and dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography to obtain 80.5 g of a monomer of the following structural formula (7).

  Next, 12.0 g of methyl ethyl ketone was added to a 100 mL three-necked flask equipped with a stirrer and a condenser, and heated to 72 ° C. under an argon stream. Here, 2.4 g (8.00 mmol) of the monomer of the structural formula (7), 1.2 g (13.9 mol) of methacrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 8.4 g (47.6 mmol) of methacrylic acid. Benzyl acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.128 g (0.56 mmol) of 2,2′-azobis (isobutyric acid) dimethyl (manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved in 6.0 g of methyl ethyl ketone. The solution was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was further reacted for 1 hour. A solution prepared by dissolving 0.06 g (0.26 mmol) of 2,2′-azobis (isobutyric acid) dimethyl in 2.0 g of methyl ethyl ketone was added and heated to 78 ° C. Stir for hours. Thereafter, reprecipitation was repeated twice using hexane to purify the copolymer. After the purification treatment, the copolymer was filtered off and dried under reduced pressure to obtain 11.6 g of a comparative copolymer RCP-3 (weight average molecular weight (Mw): 34,000).

-Preparation of comparative pigment dispersion RPD-6-
4.0 parts by mass of comparative copolymer RCP-3 was added to 1.9 parts by mass of tetraethylammonium hydroxide 35% by mass aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd.), 50.0 parts by mass of 3-methoxy-N, It was dissolved in N′-dimethylpropionamide and 28.1 parts by mass of ion exchange water.
16.0 parts by mass of carbon black (NIPEX 150, manufactured by Degussa) was added to an aqueous solution of 84.0 parts by mass of the comparative copolymer RCP-3, and the mixture was stirred for 12 hours. The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls having a diameter of 0.1 mm), and then the average pore size was measured. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 95.0 parts by mass of a comparative pigment dispersion RPD-6 (pigment solid content concentration: 16% by mass).

-Preparation of ink RGJ-6-
40.0 parts by weight of comparative pigment dispersion RPD-6, 10.0 parts by weight of 1,3-butanediol, 10.0 parts by weight of glycerin, 1.0 part by weight of 2-ethyl-1,3-hexane Diol, 1.0 part by mass of 2,2,4-trimethyl-1,3-pentanediol, 1.0 part by mass of Unidyne DSN-403N (manufactured by Daikin Industries, Ltd., solid content: 100% by mass), and 37. After 0 parts by mass of ion-exchanged water was mixed and stirred for 1 hour, it was filtered through a membrane filter having an average pore size of 1.2 μm to obtain ink RGJ-6 of Comparative Example 6.

  Next, various properties were evaluated as follows for each of the pigment dispersions and the inks of Examples 1 to 24 and Comparative Examples 1 to 6 that were produced. The results are shown in Table 6.

<Storage stability of pigment dispersion>
Each pigment dispersion was filled in 15 mL in a 30 mL capacity glass container and stored at 70 ° C. for 2 weeks. The change rate of the viscosity after storage with respect to the viscosity before storage was determined from the following formula and evaluated according to the following criteria. C and above are practical.
For the measurement of the viscosity, a viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used, and the viscosity at 25 ° C. was measured at 50 revolutions.
〔Evaluation criteria〕
A: Viscosity change rate exceeds ± 3%, within ± 5% B: Viscosity change rate exceeds ± 5%, within ± 8% C: Viscosity change rate exceeds ± 8%, ± 10% Within D: Change rate of viscosity exceeds ± 10% and within ± 30% E: Change rate of viscosity exceeds ± 30% (cannot be evaluated due to gelation)

<Ink storage stability>
Each ink was filled in an ink container and stored at 70 ° C. for 1 week. The change rate of the viscosity after storage with respect to the viscosity before storage was obtained from the following formula and evaluated according to the following criteria. C and above are practical.
For the measurement of the viscosity, a viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used, and the viscosity at 25 ° C. was measured at 50 revolutions.
〔Evaluation criteria〕
A: Viscosity change rate exceeds ± 3%, within ± 5% B: Viscosity change rate exceeds ± 5%, within ± 8% C: Viscosity change rate exceeds ± 8%, ± 10% Within D: Change rate of viscosity exceeds ± 10% and within ± 30% E: Change rate of viscosity exceeds ± 30% (cannot be evaluated due to gelation)

<Image density>
General of 64 points JIS X 0208 (1997), 2223 created by Microsoft Word 2000 (manufactured by Microsoft) by filling each ink in an ink jet printer (IPSiO GX5000, manufactured by Ricoh Co., Ltd.) under an environment of 23 ° C. and 50% RH. The chart on which the symbols are described is stamped on plain paper 1 (XEROX 4200, manufactured by XEROX) and plain paper 2 (MyPaper, manufactured by Ricoh Co., Ltd.). Color), and evaluated according to the following criteria. C and above are practical.
As the print mode, a mode in which the “plain paper-standard fast” mode is changed to “no color correction” from the user setting of plain paper by a driver attached to the printer.
The general symbols of JIS X 0208 (1997) and 2223 are symbols whose outer shape is a regular square and the entire surface of the symbol is filled with ink.
〔Evaluation criteria〕
A: 1.25 or more and less than 1.27 B: 1.20 or more and less than 1.25 C: 1.10 or more and less than 1.20 D: less than 1.10 E: The pigment gelled and could not be dispersed in the ink, Cannot print

From the results shown in Table 6, the pigment dispersions prepared using the copolymers having naphthyl groups at the ends of the side chains of Examples 1 to 24 are those having no naphthyl group at the ends of the side chains of Comparative Examples 1 to 5. Compared to a pigment dispersion prepared using a polymer, it had excellent storage stability. This is presumably because the adsorptivity to the pigment was increased by the π-π interaction between the naphthyl group of the copolymer and the pigment.
Further, as in Comparative Example 6, even when the side chain has a naphthyl group at the end, depending on the selection of other monomers used for the synthesis of the copolymer, the storability of the ink can be made sufficient. Therefore, it was found difficult to ensure long-term stable quality.

The aspect of the present invention is as follows.
<1> An ink containing water, a coloring material, and a copolymer,
The copolymer includes a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
However, the general formula (1), R ₁ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, Y is an alkylene group of 5-7 carbon atoms, or carbon This represents a divalent group of an alicyclic hydrocarbon of formula 6-13.
However, In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl group. n represents an integer of 1 to 90, and m represents an integer of 0 to 90.
<2> The ink according to <1>, wherein the structural unit represented by the general formula (2) is a structural unit represented by the following general formula (2 ′).
However, in the general formula ₍₂ '), _R 2 and _{R 3} represents a hydrogen atom or a methyl group, n represents an integer of 1 to 90.
<3> The ink according to any one of <1> to <2>, wherein the content of the structural unit represented by the general formula (1) in the copolymer is 40% by mass or more and 70% by mass or less. It is.
<4> The ink according to any one of <1> to <3>, wherein the structural unit represented by the general formula (1) is any one of the structural units represented by the following structural formula.
<5> The ink according to any one of <1> to <4>, wherein n is 4 to 50 and m is 0 in the general formula (2).
<6> The ink according to any one of <1> to <5>, wherein n is 8 to 30 and m is 0 in the general formula (2).
<7> The ink according to any one of <1> to <6>, wherein the copolymer has a weight average molecular weight of 15,000 to 40,000.
<8> The ink according to any one of <1> to <7>, wherein a content of the copolymer is 0.05% by mass or more and 10% by mass or less.
<9> The ink according to any one of <1> to <8>, wherein the color material is a pigment.
<10> The ink according to any one of <1> to <9>, further including at least one of an organic solvent and a surfactant.
<11> A method for producing an ink comprising water, a coloring material, and a copolymer,
Production of an ink, wherein the copolymer is synthesized by radical polymerization from a monomer represented by the following general formula (3) and a polymerizable material containing a monomer represented by the following general formula (4): Is the method.
However, In the general formula (3), R ₄ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, Y is an alkylene group of 5-7 carbon atoms, or carbon This represents a divalent group of an alicyclic hydrocarbon of formula 6-13.
In the general formula (4), _{R 5} and _{R 6} represent a hydrogen atom or a methyl group, n represents an integer of. 1 to 90, m is an integer of 0-90.
<12> The method for producing an ink according to <11>, wherein the monomer represented by the general formula (3) is any of the monomers represented by the following structural formulas.
<13> The method for producing an ink according to any one of <11> to <12>, wherein the monomer represented by the general formula (4) is any one of methoxypolyethylene glycol methacrylate and polyethylene glycol monomethacrylate. .
<14> An ink storage container including an ink storage unit that stores ink, wherein the ink stored in the ink storage unit is the ink according to any one of <1> to <10>. This is an ink container.
<15> An image forming method comprising at least an ink flying step of recording an image by applying a stimulus to the ink according to any one of <1> to <10> and causing the ink to fly. .
<16> The image forming method according to <15>, wherein the stimulus is at least one selected from heat, pressure, vibration, and light.
<17> An image forming apparatus comprising at least ink flying means for recording an image by applying a stimulus to the ink according to any one of <1> to <10> and causing the ink to fly. .
<18> The image forming apparatus according to <17>, wherein the stimulus is at least one selected from heat, pressure, vibration, and light.
<19> An image formed product comprising an image formed using the ink according to any one of <1> to <10> on a recording medium.
<20> The image formed product according to <19>, wherein the recording medium is plain paper.

  The ink according to any one of <1> to <10>, the method for producing the ink according to any one of <11> to <13>, the ink container according to <14>, and the <15> To <16>, the image forming apparatus according to any one of <17> to <18>, and the image-formed product according to any one of <19> to <20> According to the above, the above-described problems can be solved and the object of the present invention can be achieved.

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

JP 2011-105866 A

Claims (11)

An ink containing water, a coloring material, and a copolymer,
The ink, wherein the copolymer includes a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
However, the general formula (1), R ₁ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, Y is an alkylene group of 5-7 carbon atoms, or carbon This represents a divalent group of an alicyclic hydrocarbon of formula 6-13.
However, In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl group. n represents an integer of 1 to 90, and m represents an integer of 0 to 90. The ink according to claim 1, wherein the structural unit represented by the general formula (2) is a structural unit represented by the following general formula (2 ′).
However, in the general formula ₍₂ '), _R 2 and _{R 3} represents a hydrogen atom or a methyl group, n represents an integer of 1 to 90.   The ink according to claim 1, wherein the content of the structural unit represented by the general formula (1) in the copolymer is 40% by mass or more and 70% by mass or less.   The ink according to any one of claims 1 to 3, wherein the copolymer has a weight average molecular weight of 15,000 to 40,000.   The ink according to claim 1, wherein the color material is a pigment.   The ink according to any one of claims 1 to 5, further comprising at least one of an organic solvent and a surfactant. A method for producing an ink containing water, a coloring material, and a copolymer,
Production of an ink, wherein the copolymer is synthesized by radical polymerization from a monomer represented by the following general formula (3) and a polymerizable material containing a monomer represented by the following general formula (4): Method.
However, In the general formula (3), R ₄ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, Y is an alkylene group of 5-7 carbon atoms, or carbon This represents a divalent group of an alicyclic hydrocarbon of formula 6-13.
In the general formula (4), _{R 5} and _{R 6} represent a hydrogen atom or a methyl group, n represents an integer of. 1 to 90, m is an integer of 0-90.   An ink container having an ink container for containing ink, wherein the ink stored in the ink container is the ink according to any one of claims 1 to 6. .   7. An image forming method comprising at least an ink flying step of recording an image by applying a stimulus to the ink according to claim 1 and causing the ink to fly.   7. An image forming apparatus comprising at least an ink flying unit that records an image by applying a stimulus to the ink according to claim 1 and causing the ink to fly.   An image formed product comprising an image formed using the ink according to any one of claims 1 to 6 on a recording medium.