JP6642084B2 - Ink and manufacturing method thereof, ink container, image forming method, image forming apparatus, and image formed product - Google Patents

Description

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

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

  Further, 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, and non-permeable films such as PET films are used, and high compatibility of the ink with the recording medium is required. Therefore, in the ink jet recording method, in order to prevent paper curl that occurs when printing on plain paper, or when printing on coated paper or art paper, increase the permeability of the ink to speed up drying and beading. In order to prevent this, there is a method of adding a hydrophilic organic solvent to the aqueous ink.

  In addition, the aqueous pigment ink used in the ink jet recording method or writing instrument is different from the aqueous dye ink prepared by dissolving a dye in water, because it is necessary to stably disperse a pigment that does not dissolve in water in water for a long time. Various pigment dispersants have been developed. For example, a graft polymer containing an aromatic ring in a side chain has been proposed (for example, see Patent Document 1).

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink which can obtain a high image density even when recorded on plain paper and has high storage stability.

The ink of the present invention as a means for solving the above problems is water, an ink containing 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).
Here, in 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, and Y represents an alkylene group having 5 to 7 carbon atoms or carbon atom. Represents a divalent group of an alicyclic hydrocarbon represented by Formulas 6 to 13.
However, in the general formula (2), R ₂ and R ₃ represent a hydrogen atom or a methyl group, n represents an integer of 1 to 90, and m represents an integer of 0 to 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 a perspective explanatory view illustrating an example of an image forming apparatus. FIG. 2 is a 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 other components.
The ink of the present invention is based on the finding 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.
Here, in 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, and Y represents an alkylene group having 5 to 7 carbon atoms or carbon atom. Represents a divalent group of an alicyclic hydrocarbon represented by Formulas 6 to 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 general formula (2), n and m represent an average addition mole number of ethylene oxide (C ₂ H ₄ O) and propylene oxide (C ₃ H ₆ O). n is an integer of 1 to 90, m is an integer of 0 to 90, and n is preferably 4 to 50, m is preferably 0, and n is 8 to 30, and m is an integer from the viewpoint of ink storage stability and image density. 0 is more preferred.

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 represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 90.

  In the structural unit represented by the general formula (1), a naphthyl group having one end at an end in an open end (open end, in other words, a pendant structure portion) is formed by a pigment having a color material in the ink. Due to π-π stacking, it has excellent pigment adsorption power.

Hereinafter, specific examples of the structural unit represented by the general formula (1) will be described, but the present invention is not limited to the following specific examples.

As understood from the above description of the “naphthyl group existing at the terminal 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 a main chain of a copolymer. However, naturally, it does not exclude the case where a part is included in the side chain.
For example, it is a well-known fact that it is difficult to completely eliminate a secondary radical polymerization reaction that produces a branched structure.
Further, when preparing the pigment dispersion in which the pigment is dispersed in water, when the copolymer used in the present invention is used, since a naphthyl group is present at a terminal of a side chain of the copolymer, the pigment surface The pigment is easily adsorbed and has a high adsorptivity to the pigment, so that a long-term stable pigment dispersion having high dispersibility 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 purpose. However, the content is 30% by mass or more and 80% by mass relative to the total amount of the copolymer. % Or less, more preferably 40% by mass or more and 70% by mass or less. When the content is within the preferred range, it is advantageous in that when used in an ink, the image density and storage stability become good.

  The structural unit represented by the general formula (2) and the cellulose mainly constituting the plain paper are hydrophilic. Therefore, it is considered that the structure represented by the general formula (2) has a higher affinity for cellulose than for a hydrophobic solvent. When the copolymer is used for ink, the copolymer adsorbed on the pigment at the time of printing is adsorbed on cellulose, and the pigment tends to remain on the paper surface. In the general formula (2), having a polyethylene glycol chain and a polypropylene glycol chain (n is an integer of 1 to 90, and m is an integer of 0 to 90) makes it easier to contact with cellulose and more easily adsorb to cellulose. It is considered to be. Thereby, a high image density can be exhibited 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 purpose. However, the content is 20% by mass or more and 70% by mass or more based on the total amount of the copolymer. Or less, more preferably 30% by mass or more and 60% by mass or less. When the content is within the preferred range, it is advantageous in that when used in an ink, the image density and storage stability become good.

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 can 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, and 4-chloromethylstyrene; methyl (meth) acrylate; ) 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), henicosyl (meth) acrylate (C21), Alkyl (meth) acrylates such as docosyl (meth) acrylate (C22); 1-heptene, 3,3-dimethyl-1-pentene, 4,4-dimethyl-1-pentene, 3-methyl-1-hexene, -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 , 1-nonadecene, 1-eicosene, 1-docosene and the like. These may be used alone or in combination of two or more.

Examples of the polymerizable hydrophilic monomer include, for example, maleic acid or a salt thereof, monomethyl maleate, itaconic acid, monomethyl itaconate, 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; 2-hydroxyethyl (meth) acrylate, 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 content of the polymerizable hydrophilic monomer is determined by the structural unit represented by the general formula (1) and the monomer forming the structural unit represented by the general formula (2) Is preferably 5% by mass or more and 100% by mass or less based on the total amount of

The polymerizable surfactant is an anionic or nonionic surfactant having at least one unsaturated double bond group capable of radical polymerization in a molecule.
Examples of the anionic surfactant, ammonium sulfate base ^_(-SO 3 - _NH ^{4 +)} hydrocarbon compound having a sulfate group and an allyl group _{(-CH 2} -CH = CH 2), such as, ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ sulfate group and methacrylic group, such as _{[-CO-C (CH 3) =} CH 2 ] a hydrocarbon compound having, or ammonium sulfate base ^_(-SO 3 - _NH ^{4 +)} sulfate, such as base and 1 - an aromatic hydrocarbon compound having a propenyl group (-CH = _CH 2 _{CH 3)} and the like. Examples of the anionic surfactant include Elminol JS-20 and RS-300 manufactured by Sanyo Chemical Industries, Ltd., and Aqualon KH-10, Aqualon KH-1025, and 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 surface active agent, e.g., a 1-propenyl group (-CH = _CH 2 _{CH 3)} polyoxyethylene group _{[- (C 2 H 4 O} ) n-H] a hydrocarbon compound having a or And aromatic hydrocarbon compounds. 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., and Latemul PD- manufactured by Kao Corporation. 104, Latemul PD-420, Latemul PD-430, Latemul PD-450, and the like.

The polymerizable surfactant can be used alone or in combination of two or more.
The content of the polymerizable surfactant is 0. 0 to the total amount of the structural unit represented by the general formula (1) and the monomer forming the structural unit represented by the general formula (2). It is preferably from 1% by weight to 10% by weight.

  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 the preferred range, it is advantageous in that when used in ink, the image density and storage stability are improved.

The structure of the copolymer can be analyzed by using a general analysis method such as NMR or IR.
Further, 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 determined by the monomer used in synthesizing the copolymer. Can be determined by the molar ratio of Further, it can be determined by NMR from the 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, a known polymerization method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. it can. The polymerization reaction can be performed by a known operation such as a batch system, a semi-continuous system, and a continuous system. Although not limited to these polymerization methods, a radical polymerization using a radical polymerization initiator shown below is preferable because the polymerization operation and the adjustment of the molecular weight are easy, and a solution polymerization method of polymerizing in a mixed solvent of an organic solvent and water is preferable. More preferred.

In the present invention, the copolymer containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) includes a monomer represented by the following general formula (3) and a copolymer represented by 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, and Y represents an alkylene group having 5 to 7 carbon atoms or 6 carbon atoms. And represents a bivalent group of alicyclic hydrocarbons from 1 to 13.

However, 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, and m represents an integer of 0 to 90.

Specific examples of the compound represented by the general formula (3) are shown 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) and (2), first, a diisocyanate compound (A-1) and a naphthol (A-2) are reacted in the presence of an acid acceptor such as an 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 above reaction formula (1), Y represents the same meaning as in the above general formula (3).

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

  As another method, after reacting (A-1) and (A-4) first, and then reacting with (A-2), the compound is represented by the general formula (3). A compound can be obtained.

  As another method, as shown in the following reaction formula (3), a diisocyanate compound (A-1), a naphthol (A-2), and a hydroxyalkyl methacrylate (A-4) are reacted to form the above-mentioned general compound. It is also possible to obtain a monomer represented by the formula (3).

<Reaction formula 3>
However, in the above reaction formula (2), Y and X represent the same meaning as in the above 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 may be used, or a commercially available product may be used. Examples of the commercially available products include Blemmer 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 a method for synthesizing the copolymer, a method using a radical polymerization initiator is preferable because polymerization operation and adjustment of molecular weight are easy, and a solution polymerization method in which a polymerization reaction is performed in a solution is more preferable.
Preferred solvents for performing radical polymerization by the solution polymerization method include acetone, methyl ethyl ketone, ketone solvents such as methyl isobutyl ketone, ethyl acetate, acetate solvents such as butyl acetate, and aromatic solvents such as benzene, toluene, and xylene. Examples thereof include hydrocarbon solvents, isopropanol, ethanol, cyclohexane, tetrahydrofuran, dimethylformamide, dimethylsulfoxide, and hexamethylphosphamide. Among these, ketone solvents, acetate solvents, and alcohol solvents are preferred.

  The radical polymerization initiator is not particularly limited and can be appropriately selected depending on the intended purpose.For example, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, peroxyester , Cyano-based azobisisobutyronitrile, azobis (2-methylbutyronitrile), azobis (2,2'-isovaleronitrile), non-cyano-based dimethyl-2,2'-azobisisobutyrate 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 purpose. However, the content is preferably 1% by mass or more and 10% by mass or less based on the total amount of the 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, dodecylmercaptan, 1-dodecanethiol, and thioglycerol.
The polymerization temperature is not particularly limited and may be appropriately selected depending on the intended purpose. The polymerization temperature is preferably from 50 ° C to 150 ° C, more preferably from 60 ° C to 100 ° C. The polymerization time is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 3 hours or more and 48 hours or less.

The copolymer used in the present invention is not particularly limited, and can be used both as a pigment dispersant and as an additive to a pigment dispersion. When used as a pigment dispersant, further improvement in storage stability in inks containing a large amount of a water-soluble organic solvent is recognized.
The content of the copolymer used in the present invention, when used as a pigment dispersant, is not particularly limited and can be appropriately selected depending on the intended purpose. It is preferably from 1 to 100 parts by mass, more preferably from 5 to 80 parts by mass. When the content is within the more preferable range, it is advantageous in that the image density and the storage stability are improved. Further, other dispersants may be used in combination as long as the effect of the copolymer as a dispersant is not impaired.

The content of the copolymer is not particularly limited and can be appropriately selected depending on 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. The content is more preferably from 0.3% by mass to 5% by mass.
When the content is 0.05% by mass or more, an effect of improving dispersibility and storage stability is recognized. When the content is 10% by mass or less, it is possible to set a viscosity range suitable for discharging ink from a head. Become.

<Water>
As the water, for example, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, or ultrapure water can be used.
The content of the water in the ink is not particularly limited and can be appropriately selected depending on the intended purpose; however, from the viewpoint of drying properties and ejection reliability of the ink, the content is preferably from 10% by mass to 90% by mass, The content is more preferably from 20% by mass to 60% by mass.

<Color material>
Pigments or dyes can be used as the coloring material. Pigments are preferred in that pigments are superior to dyes in the ability of the copolymer to adsorb to colorants, and in terms of water resistance and light resistance.

  The pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a black or color inorganic pigment and an organic pigment. These may be used alone or in combination of two or more.

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

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

Examples of the azo pigment include an azo lake, an insoluble azo pigment, a condensed azo pigment, a chelate azo pigment and the like.
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 quinoflurone pigment, and a rhodamine B lake pigment. .
Examples of the dye chelates include basic dye chelates and acid dye chelates.

  The pigment for yellow is not particularly limited and can be appropriately selected depending on the intended 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 for magenta is not particularly limited and can 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 can 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; I. Bat Blue 4, C.I. I. Bat Blue 60 and the like.

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

In the ink of the present invention, a coloring material newly manufactured for the present invention can be used.
Further, from the viewpoint of the coloring property of the obtained image, a self-dispersion pigment may be used, and an anionic self-dispersion pigment is preferable. The anionic self-dispersing pigment refers to a pigment which has been dispersed and stabilized by introducing an anionic functional group directly or via another atomic group onto the surface of the pigment.
As the pigment before dispersion stabilization, various conventionally known pigments such as those listed in WO 2009/014242 can be used.
The anionic functional group refers to a functional group at which half or more 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 them, a carboxyl group or a phosphonic acid group is preferable from the viewpoint of increasing the optical density of the obtained image.
As a method for introducing an anionic functional group on the surface of the pigment, for example, a method of oxidizing carbon black can be mentioned.
As specific examples of the oxidation treatment method, a method of treating with hypochlorite, ozone water, hydrogen peroxide, chlorite, nitric acid, or the like, Japanese Patent No. 3808504, Japanese Patent Publication No. 2009-515007, And a surface treatment method using a diazonium salt as described in JP-T-2009-506196.
Commercially available pigments having a hydrophilic functional group introduced on the surface include, for example, CW-1, CW-2, and CW-3 (all manufactured by Orient Chemical Co., Ltd.); CAB-O-JET200, CAB- O-JET300, CAB-O-JET400 (manufactured by Cabot) and the like.

  The content of the pigment in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. The content 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 into acid dyes, direct dyes, basic dyes, reactive dyes and food dyes in a color index can be used.
Examples of the acid dye and food dye 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, and the like.
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 and the like.
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 and the like.

  The ink of the present invention has an organic solvent for enhancing permeability to plain paper, coated paper, and the like, further suppressing occurrence of beading, and preventing drying of the ink by using a wetting effect. It is preferred 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, 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- Nitrogen-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; And ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or less, because it not only functions as a wetting agent but also provides good drying properties.

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

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

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected depending on the intended purpose; however, from the viewpoint of drying properties and ejection reliability of the ink, the content is preferably from 10% by mass to 60% by mass, The content is more preferably from 20% by mass to 60% by mass.

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

<Surfactant>
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the purpose. Among them, those which do not decompose even at a high pH are preferable, and examples thereof include side-chain-modified polydimethylsiloxane, both-end-modified polydimethylsiloxane, one-end-modified polydimethylsiloxane, and both-chain-end both-end modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. In addition, a polyether-modified silicone-based surfactant can also be used as the silicone-based surfactant, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.
Examples of the fluorine-based surfactant include a perfluoroalkylsulfonic acid compound, a perfluoroalkylcarboxylic acid compound, a perfluoroalkylphosphate ester compound, a perfluoroalkylethylene oxide adduct, and a perfluoroalkylether group in a side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid and perfluoroalkylsulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain include a sulfate salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in a side chain, and having a perfluoroalkyl ether group in a side chain. Salts of a polyoxyalkylene ether polymer are exemplified. The counter ions of the salts in these fluorinated surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , and NH (CH ₂ CH ₂ OH) _{3 and the} like.
Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, and the like.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurylate, and polyoxyethylene alkyl ether sulfate. These may be used alone or in combination of two or more.

The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include side-chain modified polydimethylsiloxane, both-terminal-modified polydimethylsiloxane, one-terminal-modified polydimethylsiloxane, Examples include polydimethylsiloxane modified at both ends of the chain, and a polyoxyethylene group having a modifying group, and a polyether-modified silicone surfactant having a polyoxyethylene polyoxypropylene group exhibiting good properties as an aqueous surfactant. preferable.
As such a surfactant, an appropriately synthesized one may be used, 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., Dow Corning Toray Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd.
The polyether-modified silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the polyalkylene oxide structure represented by the general formula (S-1) may be a dimethylpolysiloxane. Examples include those introduced into the side chain of the siloxane in the siloxane.
[General formula (S-1)]
(In the general formula (S-1), m, n, a, and b represent an integer. R and R ′ represent an alkyl group or an alkylene group.)
Commercially available products can be used as the above-mentioned polyether-modified silicone-based 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 (Big Chemie Co., Ltd.), TSF4440, TSF4452, and TSF4453 (Toshiba Silicon Co., Ltd.).

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 fluorine-based surfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain.
Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because of low foaming property, and particularly, fluorine-based compounds represented by the general formulas (F-1) and (F-2). Surfactants are preferred.
[General formula (F-1)]
In the compound represented by the above 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} and n is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ —CnF _{2n + 1} and n is 4 to 6. P is an integer of 1 to 19 at an integer or CpH _{2p + 1} . a is an integer of 4 to 14.
A commercially available product may be used as the above-mentioned fluorine-based surfactant.
Examples of commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullard 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 OMNOVA), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), etc. From the viewpoint that the quality, particularly the color developing property, the permeability to paper, the wettability, and the leveling property are significantly improved, FS-300 manufactured by DuPont, FT-110, FT-250, FT-251, and FT manufactured by Neos Co., Ltd. -400S, FT-150, FT-400SW, Polyfox PF-151N manufactured by Omnova and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferred.

  The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the purpose. However, from the viewpoint of excellent wettability and ejection stability and improved image quality, 0.001 mass % To 5% by mass, more preferably 0.05% to 5% by mass.

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

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

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

<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.

The physical properties of the ink are not particularly limited and can be appropriately selected depending on the purpose. For example, the viscosity, surface tension, pH, and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, and more preferably 5 mPa · s or more and 25 mPa · s or less, from the viewpoint of improving print density and character quality, and obtaining good ejection properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. As measurement conditions, measurement can be performed at 25 ° C. with a standard cone rotor (1 ° 34 ′ × R24), a sample liquid amount of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less, 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 from 7 to 12, and more preferably from 8 to 11, from the viewpoint of preventing corrosion of the metal member that comes into contact with the ink.

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

The other steps include, for example, a mixing step.
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.
The copolymer may be used as a pigment dispersion resin in producing a pigment dispersion.
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic dispersion, or the like. The stirring and mixing can be performed by a stirrer using a general 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>
The ink record of the present invention has an image formed on a recording medium using the ink of the present invention.
A recorded matter can be obtained by recording using an inkjet recording apparatus and an inkjet recording method.

(Ink storage container)
The ink container of the present invention is an ink container having an ink container for storing ink, and the ink stored in the ink container is the ink of the present invention. It contains the ink in a container, and further has other members appropriately selected as needed.
The container is not particularly limited, and its shape, structure, size, material, and the like can be appropriately selected depending on the purpose.For example, an aluminum laminate film, at least an ink storage portion formed of a resin film, or the like can be used. Are preferred.

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

  The method of using the ink is not limited to the ink jet recording method, but can be widely used. In addition to 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 according to the purpose. For example, the ink can be applied to printed matter, paints, coating materials, base materials, and the like. Further, 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 object).
As a three-dimensional modeling device for modeling a three-dimensional molded object, a known device can be used, and is not particularly limited. For example, a device including an ink storage unit, a supply unit, a discharge unit, a drying unit, and the like is used. be able to. The three-dimensional object includes a three-dimensional object obtained by, for example, over-coating ink. Further, a molded product obtained by processing a structure obtained by applying ink on a base material such as a recording medium is also included. The molded product is obtained by subjecting a recording material or a structure formed in a sheet shape or a film shape to a molding process such as a heat drawing or a punching process. -It is suitably used for molding after decorating the surface, such as electronic equipment, meters of cameras and panels of operation units.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.
The average molecular weight of the copolymer used in Examples and Comparative Examples was determined as follows.

<Measurement of average molecular weight of copolymer>
It was measured under the following conditions by GPC (Gel Permeation Chromatography).
-Equipment: GPC-8020 (manufactured by Tosoh Corporation)
・ Column: TSK G2000HXL and G4000HXL (Tosoh Corporation)
・ Temperature: 40 ° C
-Solvent: THF (tetrahydrofuran)
Flow rate: 1.0 mL / min. Inject 1 mL of the copolymer having a concentration of 0.5% by mass, and use 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. Thus, 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 Kasei Kogyo Co., Ltd.) and 30.4 g (300 mmol) of triethylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.) are dissolved in 300 mL of dry toluene, and the mixture is dissolved under an argon stream. The mixture was heated to 105 ° C. with stirring. A solution in which 43.3 g (300 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 1,500 mL of dry toluene was slowly added dropwise thereto. After the dropwise addition, the mixture was stirred at 105 ° C for 2 hours. After cooling to room temperature, the precipitate was separated by filtration 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 the mixture was stirred at room temperature for 1 hour. The white solid was filtered off to obtain 53.0 g of a reaction intermediate represented by 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 a stream of argon. To this, 0.03 g of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped, and the mixture was heated to 50 ° C. while stirring. A solution obtained 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. After the dropwise addition, the mixture was stirred at 50 ° C. for 2 hours. After cooling to room temperature, insolubles were filtered off, and the solvent was distilled off from the filtrate to obtain a paste-like 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, which was the target product.

(Monomer Synthesis Example 2)
-Synthesis of Monomer M-8-
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.) are dissolved in 200 mL of dry toluene. The mixture was heated to 105 ° C. while stirring under an argon stream. A solution in which 42.5 g (295 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 800 mL of dry toluene was slowly added dropwise thereto. After the dropwise addition, the mixture was stirred at 105 ° C for 2 hours. After cooling to room temperature, the precipitate was separated by filtration 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 the mixture was stirred at room temperature for 1 hour. The white solid was separated by filtration to obtain 55.0 g of a reaction intermediate represented by 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 a stream of argon. 0.2 g of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise thereto, and the mixture was heated to 60 ° C. with stirring. A solution obtained 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 the dropwise addition, the mixture was stirred at 60 ° C. for 2 hours. After cooling to room temperature, insolubles were filtered off, and the solvent was distilled off from the filtrate to obtain a paste-like crude product. This was purified by silica gel chromatography (toluene / ethyl acetate = 5/1) to obtain 52.0 g of monomer M-8, which was the target product.

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

  Next, 16.6 g (128 mmol) of 2-hydroxyethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 80 g of methyl ethyl ketone were placed in a reaction vessel, and 0.2 g of dibutyltin dilaurate (manufactured by Tokyo Chemical Industry Co., Ltd.). Was further added and dissolved by stirring. Next, the temperature of the solution was raised 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. Thereafter, the mixture was cooled to room temperature, the insoluble matter was removed by filtration, and the obtained filtrate was concentrated to dryness to obtain a crude product of a mixture represented by 58 g of the monomers M-10 and M-11. This was further purified by column chromatography on silica gel using a mixed solvent of toluene / ethyl acetate as a developing solvent to obtain 52 g of a mixture of the monomers M-10 and M-11, which was the target substance.

(Synthesis example 1 of copolymer)
—Synthesis of Copolymer CP-1—
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 were dissolved in 200 mL of dry methyl ethyl ketone to prepare a monomer solution. . After heating 10% by 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.) was added to the remaining monomer solution. A solution in which 0.30 g of α-thioglycerol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved was added dropwise over 2.5 hours, and the mixture was stirred at 75 ° C. for 6 hours. After cooling to room temperature, the obtained reaction solution was dropped into hexane. The precipitated copolymer was separated by filtration and dried under reduced pressure to obtain 97.9 g of [copolymer CP-1] (weight average molecular weight (Mw): 21,600).

(Synthesis examples 2 to 19 of copolymer)
-Synthesis of Copolymers CP-2 to CP-19-
In Synthesis Example 1 of the copolymer, the monomers represented by the general formulas (3) and (4) were used at the contents (parts by mass) shown in Table 1 and the contents (mass) shown in Table 2 were used. [Copolymers CP-2 to 19] were obtained in the same manner as in Synthesis Example 1 of the copolymer except that the polymerization initiator (AIBN) and the chain transfer regulator (thioglycerol) were used. . The IR spectra of the obtained copolymers CP-2 to CP-19 showed the same spectra as those of the copolymer CP-1.
Next, the weight average molecular weight Mw of each of the obtained copolymers CP-2 to CP-19 is as shown in Table 2.

(Preparation Example 1 of Pigment Dispersion)
-Preparation of pigment dispersion PD-1-
To 40.0 parts by mass of a 10% by mass aqueous solution of the copolymer CP-1, 16.0 parts by mass of carbon black (NIPEX150, manufactured by Degussa) and 44.0 parts by mass of high-purity water were added and stirred for 12 hours. The resulting mixture was circulated and dispersed at a peripheral speed of 10 m / s for 1 hour using a disk-type bead mill (KDL type, manufactured by Shinmaru Enterprises Co., Ltd., using zirconia balls having a diameter of 0.1 mm) for 1 hour, and then the average pore diameter 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 to 24 of Pigment Dispersions)
-Preparation of Pigment Dispersions PD-2 to 24-
Pigment Dispersion Preparation Example 1 was prepared in the same manner as in Pigment Dispersion Preparation Example 1 except that the copolymers CP-2 to 19 were used at the contents (parts by mass) shown in Table 3 and the pigments shown in Table 3 were used. Similarly, pigment dispersions PD-2 to PD-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 mass of pigment dispersion PD-1, 10.0 parts by mass of glycerin, 20.0 parts by mass of 1,3-butanediol, 10.0 parts by mass of 3-methoxy-N, N-dimethylpropion Amide, 1.0 part by mass of 2-ethyl-1,3-hexanediol, 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.) and 17.0 parts by mass of ion-exchanged water, stirred for 1 hour, and filtered through a membrane filter having an average pore size of 1.2 μm to obtain the ink GJ-1 of Example 1. Produced.

(Examples 2 to 24)
-Preparation of Ink GJ-2 to 24-
Ink 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 used.

(Comparative Example 1)
-Preparation of ink RGJ-1-
8.20 g of methoxypolyethylene glycol methacrylate (n ≒ 23) and 7.03 g of a monomer having a structure represented by the following structural formula (6) were dissolved in 30 mL of dry methyl ethyl ketone to prepare a monomer solution. After heating 10% by mass of the monomer solution to 75 ° C. under a stream of argon, a solution obtained by dissolving 0.556 g of 2,2-azobis (isobutyronitrile) in the remaining monomer solution is taken for 1.5 hours. The mixture was added dropwise and stirred at 75 ° C. for 6 hours. After cooling to room temperature, the obtained reaction solution was poured into hexane. The precipitated copolymer was separated by filtration 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 the comparative copolymer RCP-1 was prepared in the same manner as in Example 1.
Next, Example 1 was repeated 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 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 production 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. To obtain a comparative pigment dispersion RPD-2.
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 producing 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 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 23, Thus, a 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 producing 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 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 24, To obtain a comparative pigment dispersion RPD-4.
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) dissolved in 160 mL, and heated to 65 ° C. in a nitrogen atmosphere to react for 7 hours. The resulting solution was allowed to cool, 80 mg of dibutyltin (IV) dilaurate and a catalytic amount of hydroquinone were added, and 10.0 g of 2-methacryloyloxyethyl isocyanate was added dropwise. After heating 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, The number average molecular weight (Mn) was 1,900).
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 Of 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 the completion of the dropwise addition, the mixture was further reacted for 1 hour. Then, a solution prepared by dissolving 0.2 g of dimethyl 2,2′-azobisisobutyrate in 0.6 g of methyl ethyl ketone was added. did. Further, a solution obtained by dissolving 0.2 g of dimethyl 2,2'-azobisisobutyrate in 0.6 g of methyl ethyl ketone was added thereto, and the mixture was stirred with heating for 6 hours. After cooling, the obtained reaction solution was dropped into hexane, and the precipitated graft polymer was separated by filtration 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 the comparative copolymer RCP-2 was used instead of the 10% by mass aqueous solution of the copolymer CP-1 in the preparation of the pigment dispersion of Example 1. Thus, a comparative pigment dispersion RPD-5 was obtained.
Next, a comparative ink RGJ-5 was obtained in the same manner as in Example 1, except that the comparative pigment dispersion RPD-5 was used instead of the pigment dispersion PD-1 in the production 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.) were added to 500 mL of It was dissolved in N-methyl-2-pyrrolidinone (manufactured by Kanto Chemical Co., Ltd.) and stirred at room temperature for 1 hour. Further, the mixture was stirred at 110 ° C. for 10 hours. After cooling to room temperature, 2,500 mL of pure water was added to the obtained reaction solution, followed by stirring at room temperature for 1 hour. The precipitated solid was separated by filtration 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 the mixture was stirred in an ice bath for 30 minutes. 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 in an ice bath for 3 hours. 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, 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 represented by 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 represented by the structural formula (7), 1.2 g (13.9 mol) of methacrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), and 8.4 g (47.6 mmol) of methacryl Benzyl acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.128 g (0.56 mmol) of dimethyl 2,2′-azobis (isobutyrate) (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, and a solution of 0.06 g (0.26 mmol) of 2,2′-azobis (isobutyric acid) dimethyl dissolved in 2.0 g of methyl ethyl ketone was added. Stirred for hours. Thereafter, reprecipitation was repeated twice using hexane to purify the copolymer. After the purification treatment, the copolymer was separated by filtration 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 the comparative copolymer RCP-3 was mixed with 1.9 parts by mass of a 35% by mass aqueous solution of tetraethylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) and 50.0 parts by mass of 3-methoxy-N, It was dissolved in N′-dimethylpropionamide and 28.1 parts by mass of ion-exchanged water.
To an aqueous solution of 84.0 parts by mass of the comparative copolymer RCP-3, 16.0 parts by mass of carbon black (NIPEX150, manufactured by Degussa) was added and stirred for 12 hours. The resulting mixture was circulated and dispersed at a peripheral speed of 10 m / s for 1 hour using a disk-type bead mill (KDL type, manufactured by Shinmaru Enterprises Co., Ltd., using zirconia balls having a diameter of 0.1 mm) for 1 hour, and then the average pore diameter was measured. The solution 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 parts 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 mixing 0 parts by mass of ion-exchanged water and stirring for 1 hour, the mixture was filtered through a membrane filter having an average pore diameter of 1.2 μm to obtain ink RGJ-6 of Comparative Example 6.

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

<Storage stability of pigment dispersion>
Each pigment dispersion was filled in a glass container having a capacity of 30 mL, filled in a volume of 15 mL, and stored at 70 ° C. for 2 weeks. In addition, C or more is practical.
For the measurement of the viscosity, a viscosity at 25 ° C. was measured at 50 rotations using a viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.).
〔Evaluation criteria〕
A: Change rate of viscosity exceeds ± 3%, within ± 5% B: Change rate of viscosity exceeds ± 5%, within ± 8% C: Change rate of viscosity exceeds ± 8%, ± 10% Within: D: Change rate of viscosity exceeds ± 10%, within ± 30% E: Change rate of viscosity exceeds ± 30% (gelled and cannot be evaluated)

<Storage stability of ink>
Each ink was filled in an ink container and stored at 70 ° C. for one week, and the rate of change of the viscosity after storage with respect to the viscosity before storage was determined from the following formula, and evaluated according to the following criteria. In addition, C or more is practical.
For the measurement of the viscosity, a viscosity at 25 ° C. was measured at 50 rotations using a viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.).
〔Evaluation criteria〕
A: Change rate of viscosity exceeds ± 3%, within ± 5% B: Change rate of viscosity exceeds ± 5%, within ± 8% C: Change rate of viscosity exceeds ± 8%, ± 10% Within: D: Change rate of viscosity exceeds ± 10%, within ± 30% E: Change rate of viscosity exceeds ± 30% (gelled and cannot be evaluated)

<Image density>
Under an environment of 23 ° C. and 50% RH, an ink-jet printer (IPSiO GX5000, manufactured by Ricoh Co., Ltd.) was filled with each ink, and 64 points of JIS X 0208 (1997), 2223 prepared by Microsoft Word2000 (manufactured by Microsoft) were used. The chart on which the symbols are described is printed on plain paper 1 (XEROX4200, manufactured by XEROX) and plain paper 2 (MyPaper, manufactured by Ricoh Co., Ltd.), and the symbol portion on the printing surface is converted to X-Rite 938 (X-Rite, Inc.). Color) and evaluated according to the following criteria. In addition, C or more is practical.
The print mode used was a mode in which the "plain paper-standard fast" mode was changed to "no color correction" from the plain paper user setting by the driver attached to the printer.
The general symbols of JIS X 0208 (1997) and 2223 are symbols whose outer shape is a square and whose entire surface 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 1.25 D: less than 1.10 E: The pigment gelled and could not be dispersed in the ink, Cannot print

From the results in Table 6, the pigment dispersions prepared by using the copolymers having a naphthyl group at the end of the side chain in Examples 1 to 24 show the copolymers having no naphthyl group at the end of the side chain in Comparative Examples 1 to 5. It had excellent storage stability as compared with a pigment dispersion prepared using a polymer. This is presumably because the π-π interaction between the naphthyl group of the copolymer and the pigment increased the adsorptivity to the pigment.
Also, as in Comparative Example 6, even if it has a naphthyl group at the terminal of the side chain, the storage stability of the ink can be made sufficient depending on the selection of other monomers used for the synthesis of the copolymer. It was difficult to guarantee long-term stable quality.

Embodiments of the present invention are as follows.
<1> An ink containing water, a coloring material, and a copolymer,
The ink is characterized in that the copolymer contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
Here, in 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, and Y represents an alkylene group having 5 to 7 carbon atoms or carbon atom. Represents a divalent group of an alicyclic hydrocarbon represented by Formulas 6 to 13.
However, in the general formula (2), R ₂ and R ₃ represent 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 represent a hydrogen atom or a methyl group, and 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 from 40% by mass to 70% by mass. 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 structural units represented by the following structural formulas.
<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 the 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 coloring 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 containing water, a coloring material, and a copolymer,
Ink production characterized in that the copolymer is synthesized from a monomer represented by the following general formula (3) and a polymerizable material containing a monomer represented by the following general formula (4) by radical polymerization. Is the way.
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, and Y represents an alkylene group having 5 to 7 carbon atoms or carbon atom. Represents a divalent group of an alicyclic hydrocarbon represented by Formulas 6 to 13.
However, 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, and m represents an integer of 0 to 90.
<12> The method for producing an ink according to <11>, wherein the monomer represented by the general formula (3) is any one of 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 a characteristic ink storage container.
<15> An image forming method characterized by including at least an ink flying step of applying a stimulus to the ink according to any one of <1> to <10> to fly the ink and record an image. .
<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 applying a stimulus to the ink according to any one of <1> to <10>, and flying the ink to record an image. .
<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 having an image formed on a recording medium using the ink according to any one of <1> to <10>.
<20> The image formed article according to <19>, wherein the recording medium is plain paper.

  The ink according to any one of <1> to <10>, the method for producing an 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 forming product according to any one of <19> to <20>. According to this, the above-mentioned problems in the related art 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), and yellow (Y) Main tank 411 Ink storage section 413 Ink discharge port 414 Storage container case 420 Mechanism section 434 Discharge head 436 Supply tube

JP 2011-105866 A

Claims (11)

Water, a coloring material, and an ink containing a copolymer,
An ink characterized in that the copolymer contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
Here, in 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, and Y represents an alkylene group having 5 to 7 carbon atoms or carbon atom. Represents a divalent group of an alicyclic hydrocarbon represented by Formulas 6 to 13.
However, in the general formula (2), R ₂ and R ₃ represent 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 represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 90.   3. The ink according to claim 1, wherein a 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 any one of claims 1 to 4, wherein the coloring material is a pigment.   The ink according to claim 1, further comprising at least one of an organic solvent and a surfactant. Water, a coloring material, and a method for producing an ink containing a copolymer,
Ink production characterized in that the copolymer is synthesized from a monomer represented by the following general formula (3) and a polymerizable material containing a monomer represented by the following general formula (4) by radical polymerization. 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, and Y represents an alkylene group having 5 to 7 carbon atoms or carbon atom. Represents a divalent group of an alicyclic hydrocarbon represented by Formulas 6 to 13.
However, 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, and m represents an integer of 0 to 90.   An ink container having an ink container for storing ink, wherein the ink contained in the ink container is the ink according to any one of claims 1 to 6. .   An image forming method, comprising: at least an ink flying step of applying a stimulus to the ink according to any one of claims 1 to 6 to fly the ink and record an image.   An image forming apparatus, comprising: at least ink flying means for applying a stimulus to the ink according to any one of claims 1 to 6 to fly the ink and record an image.   An image formed article having an image formed on a recording medium using the ink according to any one of claims 1 to 6.