JP6733282B2 - Ink and manufacturing method thereof, ink container, image forming method, image forming apparatus, and image formed article - Google Patents

Description

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

The ink jet recording method is popular because it has an advantage that a process is simpler than other recording methods, full colorization is easy, and a high-resolution image can be obtained even with an apparatus having a simple structure. It is expanding from personal to office applications, commercial printing and industrial printing.

In such an ink jet recording system, an aqueous ink composition using a water-soluble dye as a coloring material is mainly used, but since it has a drawback of poor water resistance and light resistance, a water-insoluble alternative to the water-soluble dye is used. The development of pigment inks using these pigments is in progress.

In inkjet printing for office use, plain paper is mainly used as a recording medium, and 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 becomes low and the image density decreases. 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.

Further, in the field of commercial printing and industrial printing, there is a need for a technique capable of stably producing an image with higher resolution and higher definition 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 compatibility of ink with the recording medium is required. In the ink jet recording method, in order to prevent paper curl which occurs when printing on plain paper, or when printing on coated paper or art paper, ink permeability is increased 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.

Further, the water-based pigment ink used in the ink jet recording system or the writing instrument, unlike the water-based dye ink prepared by dissolving a dye in water, needs to disperse a water-insoluble pigment stably in water for a long period of time. , Various pigment dispersants have been developed. For example, a graft polymer having an aromatic ring in its side chain has been proposed (see, for example, Patent Document 1).

It is an object of the present invention to provide an ink that 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 an ink containing water, a coloring material, and a copolymer, and the copolymer has a structure represented by the following general formula (1). A unit and a structural unit represented by the following general formula (2) are included.
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, carbon atoms Y is including substituted or unsubstituted aromatic ring It represents a hydrocarbon group of 6 to 15.
In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl radical, n is. 1 to 90, m is an integer of 0-90.

According to the present invention, it is possible to provide an ink having a high storage stability and a high image density even when recorded on plain paper.

FIG. 1 is a perspective explanatory view showing an example of an inkjet recording apparatus. FIG. 2 is a perspective explanatory view showing an example of a main tank in the inkjet recording 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 finding that long-term storage stability is insufficient when a conventional graft polymer is used as a pigment dispersant.

<Copolymer>
The copolymer contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and further contains other structural units as necessary.
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, carbon atoms Y is including substituted or unsubstituted aromatic ring It represents a hydrocarbon group of 6 to 15. The carbon number of the hydrocarbon group includes the carbon number of the substituent.
The aromatic ring is appropriately selected depending on the intended purpose without any limitation, and examples thereof include a benzene ring, a condensed benzene ring, a non-benzene aromatic ring, and a complex aromatic ring.
The fused benzene ring is appropriately selected depending on the intended purpose without any limitation, and examples thereof include a naphthalene ring, a pyrene ring, and an anthracene ring.
The non-benzene aromatic ring is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a tropylium ring and a cyclopropenium ring.
The composite aromatic ring is appropriately selected depending on the intended purpose without any limitation, and examples thereof include a pyridine ring, a pyrrole ring, and a carbazole ring.
Examples of the substituent of the aromatic ring of Y include 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} represents a hydrogen atom or a methyl radical, n is. 1 to 90, m is an integer of 0-90.
In the general formula (2), n and m represent the average number of added moles of ethylene oxide (C ₂ H ₄ O) and propylene oxide (C ₃ H ₆ O), and n is an integer of 1 to 90. , M represents an integer of 0 to 90, and from the viewpoint of ink storage stability and image density, n is preferably 4 to 50, m is preferably 0, n is 8 to 30, and m is 0. More preferable.

The structural unit represented by the general formula (2) is preferably a structural unit represented by the following general formula (3).
However, in the general formula (3), 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), the naphthyl group present at one end at the open end (open end, that is, the pendant structure portion) has a pigment which is a coloring material in the ink. Due to π-π stacking, it has excellent pigment adsorption power.

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

As will be understood from the description of the above-mentioned “naphthyl group existing at the terminal of the pendant structure part”, the structural unit represented by the general formula (1) typically has a pendant group such as a terminal naphthyl group. It may be the backbone of the copolymer. However, of course, the case where a part is contained in the side chain is not excluded.
For example, it is a well known fact that it is difficult to completely eliminate the secondary radical polymerization reaction that produces a branched structure.
Further, when a pigment dispersion in which a pigment is dispersed in water is prepared, when the copolymer used in the present invention is used, a naphthyl group is present at the terminal of the side chain of the copolymer, so that the pigment surface is present. Since it is easily adsorbed and has a high adsorptivity with the pigment, 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 appropriately selected depending on the intended purpose without any limitation, but it 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% by mass or more and 70% by mass or less is more preferable. When the content is within the preferable range, it is advantageous in that the image density and the storage stability are good when used in the ink.

Cellulose mainly constituting the structural unit represented by the general formula (2) and plain paper is hydrophilic. Therefore, it is considered that the structural unit represented by the general formula (2) has 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 the cellulose, and the pigment easily stays on the paper surface. It is considered that, in the general formula (2), n has a polyethylene glycol chain of 1 to 90 and m has a polypropylene glycol chain of 0 to 90, so that it is easy to contact with cellulose and more easily adsorbed to cellulose. As a result, 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, but is 20% by mass or more and 70% by mass or less with respect to the total amount of the copolymer. The following is preferable, and 30% by mass or more and 60% by mass or less is more preferable. When the content is within the preferable range, it is advantageous in that the image density and the storage stability are good when used in the ink.

The copolymer may have a structural 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 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, (meth) ) Ethyl acrylate, n-butyl (meth)acrylate, dimethyl maleate, dimethyl itaconic acid, 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) Alkyl (meth)acrylates such as eicosyl acrylate (C20), henicosyl acrylate (C21), and docosyl acrylate (C22); 1-heptene, 3,3-dimethyl-1-pentene, 4 ,4-Dimethyl-1-pentene, 3-methyl-1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene, 1-octene, 3,3-dimethyl-1-hexene, 3,4 -Dimethyl-1-hexene, 4,4-dimethyl-1-hexene, 1-nonene, 3,5,5-trimethyl-1-hexene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1 Unsaturated ethylene monomers having an alkyl group such as tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 1-docosene and the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the polymerizable hydrophilic monomer include 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,N-dimethylacrylamide , Nt-butyl acrylamide, N-octyl acrylamide, Nt-octyl acrylamide and the like nonionic unsaturated ethylene monomers.
The polymerizable hydrophobic monomer and the polymerizable hydrophilic monomer may be used alone or in combination of two or more.
As the content of the polymerizable hydrophobic monomer and the polymerizable hydrophilic monomer, the structural unit represented by the general formula (1) and the monomer forming the structural unit represented by the general formula (2) 5 mass% or more and 100 mass% or less is preferable with respect to the total amount.

The polymerizable surfactant is an anionic or nonionic surfactant having at least one radically polymerizable unsaturated double bond 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 _{[-CO-C (CH 3) =} CH 2 ], such as the hydrocarbon compound having, or ammonium sulfate base ^_(-SO 3 - _NH ^{4 +),} such as sulfate groups and one - an aromatic hydrocarbon compound having a propenyl group (-CH = _CH 2 _{CH 3)} and the like. Examples of the anionic surfactant include Eleminol JS-20 and RS-300 manufactured by Sanyo Kasei Co., Ltd., Aqualon KH-10, Aqualon KH-1025, and Aqualon KH-05 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. , Aqualon HS-10, Aqualon HS-1025, Aqualon BC-0515, Aqualon BC-10, Aqualon BC-1025, Aqualon BC-20, and Aqualon BC-2020.

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 Examples thereof include aromatic hydrocarbon compounds. Specific examples of the nonionic surfactants include Aqualon RN-20, Aqualon RN-2025, Aqualon RN-30, and Aqualon RN-50 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Latemur PD-produced by Kao Corporation. 104, latemuru PD-420, latemuru PD-430, latemuru PD-450, and the like.

The polymerizable surfactant may be used alone or in combination of two or more.
The content of the polymerizable surfactant is 0 with respect 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). It is preferably 1% by mass or more and 10% by mass or less.

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

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 was used when synthesizing the copolymer. It can be determined by the molar ratio of the monomers. Further, it can be determined by NMR from the copolymer.

<Method for synthesizing copolymer>
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 is a monomer represented by the following general formula (4) and the following general formula: It is preferably synthesized by radical polymerization from a polymerizable material (starting material) containing the monomer represented by (5).
However, in the general formula (4), R ₄ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, and Y represents 6 carbon atoms including a substituted or unsubstituted aromatic ring. Represents a hydrocarbon group of ~15. The carbon number of the hydrocarbon group includes the carbon number of the substituent.

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

Specific examples of the monomer represented by the general formula (4) are shown below, but the invention is not limited to the following specific examples.

The monomer represented by the general formula (4) 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 amine or pyridine. Then, a reaction intermediate (A-3) is obtained. Then, the hydroxyalkyl methacrylate (A-4) can be reacted with the (A-3) to obtain the monomer represented by the general formula (4).

<Reaction formula (1)>
However, in the reaction formula (1), Y has the same meaning as in the general formula (4).

<Reaction formula (2)>
However, in the reaction formula (2), R ₄ , X, and Y have the same meanings as in the general formula (4).

As another method, first, the above-mentioned (A-1) and (A-4) are reacted with each other, and then the above-mentioned (A-2) is reacted therewith to obtain the compound represented by the general formula (4). 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 react with the above-mentioned general formula. It is also possible to obtain the monomer represented by (4).

<Reaction formula (3)>
However, in the reaction formula (3), R ₄ , X, and Y have the same meanings as in the general formula (4).

The compound represented by (A-1) is not particularly limited as long as Y is a diisocyanate composed of a hydrocarbon group having a carbon number of 6 to 15 and containing an aromatic ring. For example, the following may be mentioned.
4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene bis(1-methylethane-1,1-diyl) diisocyanate, m-xylylene diyl diisocyanate, naphthalene- 1,5-diyl diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 1,4-phenylene diisocyanate, 2-methyl-1,4-phenylene diisocyanate, naphthalene-1,4-diisocyanate, naphthalene- 2,6-diyl diisocyanate, naphthalene-2,7-diyl diisocyanate, 2,2'-dimethoxybiphenyl-4,4'-diyl diisocyanate, 5-methyl-1,3-phenylene diisocyanate, methylene bis(2,1-phenylene) ) Diisocyanate, 4-[(2-isocyanatophenyl)methyl]phenyl isocyanate, 2,4,6-triisopropylbenzene-1,3-diyl diisocyanate, methylene bis(2-methyl-4,1-phenylene) diisocyanate, 4 ,4'-ethylenebis(1-isocyanatobenzene), 1-(trifluoromethyl)-2,2,2-trifluoroethylidenebis(4,1-phenylene)diisocyanate, biphenyl-4,4'-diyldiisocyanate 1,4-phenylenebis(ethylene)diisocyanate, naphthalene-1,4-diylbis(methylene)diisocyanate, naphthalene-1,5-diylbis(methylene)diisocyanate, 4-ethyl-1,3-phenylene diisocyanate, 4-isopropyl -1,3-phenylene diisocyanate, 2,4-dimethyl-1,3-phenylene diisocyanate, 4,6-dimethyl-1,3-phenylene diisocyanate, 2,5-dimethyl-1,4-phenylene diisocyanate, 4-methyl -2,6-Diethylbenzene-1,3-diyl diisocyanate, 2-methyl-4,6-diethylbenzene-1,3-diyl diisocyanate, 2,4,6-triethylbenzene-1,3-diyl diisocyanate, 4-( Trifluoromethyl)benzene-1,2-diyl diisocyanate, 4-chlorobenzene-1,3-diyl diisocyanate, 2,4-dichlorobenzene-1,3-diisocyanate, 4,6-dichlorobenzene-1,3-diyl Diisocyanate, 6-methyl-4-bromoben Zen-1,3-diisocyanate, 4-(trifluoromethyl)benzene-1,3-diyldiisocyanate, 2,5-dichlorobenzene-1,4-diyldiisocyanate, 2-(trifluoromethyl)benzene-1,4 -Diyl diisocyanate, 2-methyl-6-bromobenzene-1,4-diyl diisocyanate, 2-nitrobenzene-1,4-diisocyanate, 2,6-dimethylbenzene-1,4-diyl diisocyanate, 2,6-diethylbenzene- 1,4-diyl diisocyanate, 4-methoxybenzene-1,3-diyl diisocyanate, 4-ethoxybenzene-1,3-diisocyanate, 2-methoxybenzene-1,4-diyl diisocyanate, 2,5-dimethoxybenzene-1 ,4-diyl diisocyanate, 2,5-diethoxybenzene-1,4-diyl diisocyanate, biphenyl-2,4'-diyl diisocyanate, 2-nitrobiphenyl-4,4'-diyl diisocyanate, methylenebis(2-chloro- 4,1-phenylene)diisocyanate, methylenebis(3-methyl-4,1-phenylene)diisocyanate, 4-[(4-isocyanatophenyl)methyl]-2-methoxyphenylisocyanate, 3-[(4-isocyanatophenyl) ) Methyl]-2,4,6-trimethylphenyl isocyanate, isopropylidene bis(4,1-phenylene) diisocyanate, [(tetralin)-1,5-diyl]diisocyanate, 9H-fluorene-2,7-diyl diisocyanate, 9H-carbazole-3,6-diyl diisocyanate and the like can be mentioned. These may be used alone or in combination of two or more.
Among these, methylenediphenyl-4,4′-diisocyanate, m-xylylenediyldiisocyanate, m-phenylenebis(1-methylethane-1,1-diyl)diisocyanate from the viewpoint of image density and storability when ink is prepared. , Naphthalene-1,5-diyl diisocyanate and 2,4-tolylene diisocyanate are preferred.

The monomer represented by the general formula (5) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include methoxy polyethylene glycol methacrylate, polyethylene glycol monomethacrylate, methoxy polyethylene glycol monoacrylate and polyethylene glycol. Examples thereof include polypropylene glycol monomethacrylate. These may be used alone or in combination of two or more.

As the monomer represented by the general formula (5), those synthesized appropriately may be used, or commercially available products may be used. Examples of the commercial product include Bremmer PE-90, PE-200, PE-350, AE-90U, AE-200, AE-400, PME-100, PME-200, PME-400, PME-1000, PME. -4000, AME-200, AME-400, 50PEP-300, 70PEP-350B (all made by NOF CORPORATION) etc. are mentioned.

As a method for synthesizing the copolymer, a method using a radical polymerization initiator is preferable, and a solution polymerization method in which a polymerization reaction is carried out in a solution is more preferable, because the polymerization operation and the adjustment of the molecular weight are easy.
As a preferable solvent when performing radical polymerization in the solution polymerization method, for example, acetone, methyl ethyl ketone, a ketone solvent such as methyl isobutyl ketone, ethyl acetate, acetic ester solvent such as butyl acetate, benzene, toluene, xylene, etc. Examples of the aromatic hydrocarbon solvent, isopropanol, ethanol, cyclohexane, tetrahydrofuran, dimethylformamide, dimethylsulfoxide, hexamethylphosphoamide, and the like. These may be used alone or in combination of two or more. Among these, ketone solvents, acetic acid 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. Examples thereof include peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate and peroxy ester. , Cyano-based azobisisobutyronitrile, azobis(2-methylbutyronitrile), azobis(2,2'-isovaleronitrile), non-cyano-based dimethyl-2,2'-azobisisobutyrate, etc. Are listed. Among these, organic peroxides and azo compounds are preferable, and azo compounds are more preferable, because the molecular weight is easily controlled and the decomposition temperature is low.

The content of the radical polymerization initiator is appropriately selected depending on the intended purpose without any limitation, but it is preferably 1% by mass or more and 10% by mass or less based on the total amount of the polymerizable monomers.

An appropriate amount of a chain transfer agent may be added to adjust the molecular weight of the polymer.
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 appropriately selected depending on the intended purpose without any limitation, but it is preferably 50°C or higher and 150°C or lower, more preferably 60°C or higher and 100°C or lower. The polymerization time is appropriately selected depending on the intended purpose without any limitation, but it 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 as a pigment dispersant or an additive to a pigment dispersion. When used as a pigment dispersant, further improvement in storage stability is observed in inks containing a large amount of water-soluble organic solvent.
The content of the copolymer used in the present invention is not particularly limited when it is 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 mass part or more and 100 mass parts or less are preferable, and 5 mass parts or more and 80 mass parts or less are more preferable. When the content is within the more preferable range, it is advantageous in that the image density and the storage stability are good. Further, other dispersants may be used in combination as long as the effect of the copolymer as a pigment dispersant is not impaired.

The content of the copolymer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.05% by mass or more and 10% by mass or less based on the total amount of the ink in terms of solid content. It is preferably 0.3% by mass or more and 5% by mass or less. When the content is 0.05% by mass or more, the effect of improving the image density and the storage stability is recognized, and when it is 10% by mass or less, the viscosity range suitable for ejecting the ink from the head can be obtained. Becomes

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

As the water, for example, deionized water, ultrafiltered water, reverse osmosis water, pure water such as distilled water, or ultrapure water can be used.

<Color material>
A pigment or dye can be used as the coloring material. Pigments are preferable in terms of adsorption ability of the above-mentioned copolymer to a coloring material, as compared with dyes, and pigments are preferable in terms of water resistance and light resistance.

The pigment is appropriately selected depending on the intended purpose without any limitation, and examples thereof include black or color inorganic pigments and organic pigments. 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, chrome yellow, and 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 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). , 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 and has a primary particle size of 15 nm or more and 40 nm or less, a specific surface area by the BET method of 50 m ² /g or more and 300 m ² /g or less, and a DBP oil absorption of 40 mL. /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 that can be used include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black.
Of these pigments, those having a good affinity for water are particularly preferably used.

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

The yellow pigment is not particularly limited and may 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 magenta pigment is not particularly limited and may be appropriately selected depending on the intended purpose. For example, C.I. I. Pigment Red 5, C.I. I. Pigment Red 7, C.I. I. Pigment Red 12, C.I. I. Pigment Red 48 (Ca), C.I. I. Pigment Red 48 (Mn), C.I. I. Pigment Red 57 (Ca), C.I. I. Pigment Red 57:1, C.I. I. Pigment Red 112, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 146, C.I. I. Pigment Red 168, C.I. I. Pigment Red 176, C.I. I. Pigment Red 184, C.I. I. Pigment Red 185, C.I. I. Pigment Red 202, Pigment Violet 19, and the like.

The cyan pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 2, C.I. I. Pigment Blue 3, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15:3, C.I. I. Pigment Blue 15:4, C.I. I. Pigment Blue 15:34, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 22, C.I. I. Pigment Blue 60, C.I. I. Pigment Blue 63, C.I. I. Pigment Blue 66; C.I. I. Bat Blue 4, C.I. I. Bat blue 60 and the like can be mentioned.

As a yellow pigment, C.I. I. Pigment Yellow 74, a magenta pigment such as C.I. I. Pigment Red 122, C.I. I. Pigment Violet 19, C.I. as a cyan pigment. I. By using Pigment Blue 15:3, a well-balanced ink having excellent color tone and light resistance can be obtained.

The coloring material newly manufactured for the present invention can also be used for the ink of the present invention.
Further, from the viewpoint of color developability of the obtained image, a self-dispersion pigment may be used, and an anionic self-dispersion pigment is preferable. The anionic self-dispersion pigment refers to a pigment that is dispersion-stabilized by introducing an anionic functional group into the pigment surface directly or via another atomic group.
As the pigment before dispersion stabilization, various conventionally known pigments such as those listed in International Publication No. 2009/014242 can be used.
The anionic functional group means a functional group capable of dissociating more than half of hydrogen ions 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 of introducing an anionic functional group onto the surface of the pigment include a method of oxidizing carbon black.
Specific examples of the method of the oxidation treatment include, for example, a method of treating with hypochlorite, ozone water, hydrogen peroxide, chlorite, nitric acid, etc., Japanese Patent No. 3808504, and Japanese Patent Publication No. 2009-. 515007 and Japanese Patent Publication No. 2009-506196, surface treatment methods using a diazonium salt can be mentioned.
Examples of commercially available pigments having hydrophilic functional groups introduced on the surface include CW-1, CW-2, CW-3 (above, manufactured by Orient Chemical Industry Co., Ltd.); CAB-O-JET200, CAB- O-JET300, CAB-O-JET400 (above, Cabot Corporation make) etc. are 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 1% by mass or more and 10% by mass or less. Is more preferable.

As the dye, a dye classified into an acid dye, a direct dye, a basic dye, a reactive dye, and an edible dye in the color index can be used.
Examples of the acid dye and the 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. Hood Red 7, 9, 14 and the like can be 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 and the like can be 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 and the like.

The ink of the present invention is an organic solvent in order to enhance the permeability to plain paper or coated paper, to further suppress the occurrence of beading, and to prevent 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 polyhydric alcohols, ethers such as 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-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl Polyhydric alcohol alkyl ethers such as ethers, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone , Nitrogen-containing heterocyclic compounds such as 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N- Amides such as 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. Etc.
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 obtains 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 and 2,2,4-trimethyl-1,3-pentanediol.
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. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether and the like.

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

The content of the organic solvent in the ink is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of ink drying properties and ejection reliability, 10% by mass or more and 60% by mass or less is preferable, 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 penetrability and wettability of plain paper, coated paper and the like, and further suppress the occurrence of beading.

<Surfactant>
As the surfactant, any of silicone-based surfactants, fluorine-based surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used.
The silicone-based surfactant is not particularly limited and can be appropriately selected according to the purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and side-chain 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, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include a compound having a polyalkylene oxide structure introduced into the side chain of the Si moiety of dimethylsiloxane.
Examples of the fluorinated surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphoric acid ester compound, a perfluoroalkyl ethylene oxide adduct and a perfluoroalkyl ether group in the side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salts. As the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in its side chain, a sulfuric acid ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in its side chain, or a perfluoroalkyl ether group in its side chain Examples thereof include salts of polyoxyalkylene ether polymers. As counter ions of salts in these fluorine-based surfactants, 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) are used. _{3 and the} like.
Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of nonionic surfactants include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan. Examples thereof include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, and salt of 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 may be appropriately selected depending on the intended purpose. Examples thereof include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and side-modified. Examples include polydimethyl siloxane modified at both chain ends, and a polyether modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group shows good properties as an aqueous surfactant, preferable.
As such a surfactant, an appropriately synthesized product 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., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Kagaku, etc.
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 dimethylpolyene. Examples thereof include those introduced into the side chain of the Si portion of siloxane.
General formula (S-1)
(However, 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.)
As the above polyether-modified silicone-based surfactant, commercially available products can be used, and for example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-. 1906EX (Nippon 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, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

The fluorine-based surfactant is preferably a fluorine-substituted compound having 2 to 16 carbon atoms, more preferably a fluorine-substituted compound having 4 to 16 carbon atoms.
Examples of the fluorine-based surfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in its side chain.
Among these, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain are preferable because they have a low foaming property, and the fluorine-based compounds represented by the general formula (F-1) and the general formula (F-2) are particularly preferable. Surfactants are 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 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. An integer, or CpH _2p+1 and p is an integer of 1 to 19. a is an integer of 4-14.
A commercial item may be used as the above-mentioned fluorine-based surfactant.
Examples of this commercially available product include 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 Dainippon Ink and Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all , Du Pont, Inc.); FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all are Neos Co., Ltd.), Polyfox PF-136A, PF-156A. , PF-151N, PF-154, PF-159 (manufactured by OMNOVA), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) and the like. Among these, good print quality, especially color developability, penetration into paper. From the point that the properties, wettability, and leveling property are remarkably improved, FS-300 manufactured by Du Pont, FT-110, FT-250, FT-251, FT-400S, FT-150, and FT manufactured by Neos Co., Ltd. -400SW, Polyfox PF-151N manufactured by OMNOVA, and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferable.

The content of the surfactant in the ink is appropriately selected depending on the intended purpose without any limitation, but it is 0.001 mass% from the viewpoint of excellent wettability and ejection stability and improving image quality. % Or more and 5 mass% or less is preferable, and 0.05 mass% or more and 5 mass% or less is more preferable.

The ink of the present invention preferably contains, as the above-mentioned other components, for example, an antiseptic/antifungal agent, an anticorrosive agent, a pH adjusting agent, and the like, if necessary.

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

<Rust preventive>
The rust preventive agent is not particularly limited, and examples thereof include acid sulfite and sodium thiosulfate.

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

The physical properties of the ink are not particularly limited and may 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, from the viewpoint that the printing density and character quality are improved and good ejection properties are obtained, and 5 mPa·s or more and 25 mPa·s or less are preferable. More preferable. Here, as the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. The measurement conditions are 25° C., standard cone rotor (1°34′×R24), sample liquid volume 1.2 mL, rotation speed 50 rpm, and 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., since the ink is preferably 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 the corrosion of the metal member with which the ink comes into contact.

(Ink manufacturing 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.

Examples of the other steps include a mixing step and the like.
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 when preparing a pigment dispersion.
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, ultrasonic dispersion, or the like. The stirring and mixing can be performed with 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 matter>
The ink recorded matter of the invention has an image formed by using the ink of the invention on a recording medium.
A recorded matter can be obtained by recording with an inkjet recording apparatus and an inkjet recording method.

(Ink container)
The ink storage container of the present invention is an ink storage container including an ink storage portion that stores ink, and the ink stored in the ink storage portion is the ink of the present invention. The ink is contained in a container, and further has other members appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose. For example, at least an ink containing portion formed of an aluminum laminate film, a resin film or the like can be used. Those which have are suitable.

<Recording device, recording method>
The ink of the present invention can be suitably used for various recording apparatuses using an inkjet recording system, such as printers, facsimile machines, copying machines, printer/fax/copier multifunction machines, and three-dimensional modeling apparatuses.
In the present invention, the recording device and the recording method are a device capable of ejecting ink, various treatment liquids, and the like onto a recording medium, and a method of recording using the device. The recording medium means a medium to which ink or various treatment liquids can be attached even temporarily.
This recording apparatus can include not only a head portion for ejecting ink, but also means for feeding, conveying, 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 have a heating means used in the heating step and a drying means 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, but, 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 device and the recording method are not limited to those in which a significant image such as a character or a figure is visualized by ink. For example, it also includes one that forms a pattern such as a geometric pattern and one that models 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 limited.
Further, the recording device is not limited to a desktop type, but can be used as a wide recording device capable of printing on an A0 size recording medium, or a continuous paper wound in a roll as a recording medium. It also includes a continuous form printer.
An example of the recording device will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective 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 mechanical section 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), and yellow (Y) is packed with, for example, an aluminum laminate film. It is formed of a member. The ink container 411 is housed in a container case 414 made of plastics, for example. 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. The main tank 410 is detachably attached to the cartridge holder 404. As a result, the ink discharge ports 413 of the main tank 410 communicate with the ejection heads 434 for the respective colors via the supply tubes 436 for the respective colors, and ink can be ejected from the ejection heads 434 to the recording medium.

(Image formation)
The image-formed product of the present invention is an image-formed product having a recording layer on a recording medium, and the recording layer contains a coloring material and a copolymer and, if necessary, further contains other components.
The copolymer includes a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
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, carbon atoms Y is including substituted or unsubstituted aromatic ring It represents a hydrocarbon group of 6 to 15.
In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl radical, n is. 1 to 90, m is an integer of 0-90.
An image can be obtained by recording with an inkjet recording device and an inkjet recording method.

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 copolymers used in the examples and comparative examples was determined as follows.

<Measurement of average molecular weight of copolymer>
It measured by GPC(Gel Permeation Chromatography) on the following conditions.
-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 by a monodisperse polystyrene standard sample was used from the molecular weight distribution of the copolymer measured under the above conditions. Then, 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-1-
71.6 g (286 mmol) of methylenediphenyl-4,4'-diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.), 37.2 g (286 mmol) of 2-hydroxyethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 41.2 g. (286 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved by heating in a mixed solvent of 550 mL of 2-butanone and 250 mL of toluene. 0.15 g of dibutyldilauryl tin (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added thereto and stirred at 60° C. for 3 hours. After cooling to room temperature and adding 300 mL of toluene for dilution, the precipitate was filtered off to obtain colorless crystals. Further, 1,000 mL of n-hexane was added to the filtrate, and the precipitated colorless crystals were collected by filtration. The obtained crystals were combined, dissolved in 1,200 mL of acetone, insoluble materials were removed by filtration, 1,500 mL of n-hexane was added, the precipitate was collected by filtration, and 63.5 g of a crude product was collected. Obtained. This was purified by silica gel column chromatography (toluene/ethyl acetate=5/1) to obtain 50.8 g of a target monomer M-1 having the following structure.

(Monomer synthesis example 2)
-Synthesis of Monomer M-2-
Monomer M-2 having the following structure was obtained in the same manner as in Monomer Synthesis Example 1 except that methylenediphenyl-4,4′-diisocyanate was changed to m-xylylenediyldiisocyanate (XDI) in Monomer Synthesis Example 1. Got

(Monomer synthesis example 3)
-Synthesis of Monomer M-3-
The same procedure as in the above-mentioned Monomer Synthesis Example 1 except that the methylenediphenyl-4,4′-diisocyanate was changed to m-phenylenebis(1-methylethane-1,1-diyl)diisocyanate (TMXID) in the Monomer Synthesis Example 1. Thus, a monomer M-3 having the following structure was obtained.

(Monomer Synthesis Example 4)
-Synthesis of Monomer M-4-
Monomer M having the following structure was obtained in the same manner as in Monomer Synthesis Example 1 except that methylenediphenyl-4,4′-diisocyanate was changed to naphthalene-1,5-diyldiisocyanate (NDI) in Monomer Synthesis Example 1. -4 was obtained.

(Monomer Synthesis Example 5)
-Synthesis of Monomer M-5-
Monomer M-having the structure shown below, in the same manner as in Monomer Synthesis Example 1 except that methylenediphenyl-4,4'-diisocyanate in Monomer Synthesis Example 1 was changed to 2,4-tolylene diisocyanate (TDI). Got 5.

(Monomer Synthesis Example 6)
-Synthesis of Monomer M-6-
Monomer M-6 having the following structure was obtained in the same manner as in Monomer Synthesis Example 1 except that 2-hydroxyethyl methacrylate was changed to 2-hydroxyethyl acrylate in Monomer Synthesis Example 1.

(Monomer Synthesis Example 7)
-Synthesis of Monomer M-7-
Monomer M-7 having the following structure was obtained in the same manner as in Monomer Synthesis Example 1 except that 2-hydroxyethyl methacrylate was changed to 2-hydroxypropyl methacrylate in Monomer Synthesis Example 1.

(Monomer Synthesis Example 8)
-Synthesis of Monomer M-8-
A monomer M-8 having the following structure was obtained in the same manner as in the above-mentioned Monomer Synthesis Example 1 except that methylenediphenyl-4,4′-diisocyanate was changed to 1,4-phenylene diisocyanate in Monomer Synthesis Example 1. ..

(Monomer Synthesis Example 9)
-Synthesis of Monomer M-9-
In the monomer synthesis example 1, the following structure was obtained in the same manner as in the monomer synthesis example 1 except that methylenediphenyl-4,4′-diisocyanate was changed to 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate. A monomer having M-9 was obtained.

(Synthesis Example 1 of Copolymer)
-Synthesis of Copolymer CP-1-
56.7 g (51.0 mmol) of methoxy polyethylene glycol methacrylate (manufactured by NOF CORPORATION, n:23, m:0 in the general formula (2) above), 43.3 g (82.5 mmol) of monomer M-1 Was 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, 4.00 g of 2,2′-azobis(isobutyronitrile) was added to the remaining monomer solution (AIBN, manufactured by Tokyo Chemical Industry Co., Ltd.). Was added dropwise over 1.5 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 96.9 g of [copolymer CP-1] (weight average molecular weight (Mw): 21,600).

(Synthesis Examples 2 to 21 of copolymer)
-Synthesis of Copolymers CP-2 to 21-
In Synthetic Example 1 of the copolymer, the contents (parts by mass) shown in Table 1 below were used, and the monomers shown in the general formula (4) and the general formula (5) were used. [Copolymers CP-2 to 21] were obtained in the same manner as in Synthesis Example 1 of copolymer except that (parts by mass) of the polymerization initiator (AIBN) and the chain transfer modifier (thioglycerol) were used. It was
The weight average molecular weights Mw of the obtained copolymers CP-2 to 21 are shown in Table 2 below.
Tables 1 to 3 below show the composition and structure of the obtained copolymer.

(Preparation Example 1 of pigment dispersion)
-Preparation of Pigment Dispersion PD-1-
With respect 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 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 (KDL type, manufactured by Shinmaru Enterprises Co., Ltd., media: zirconia balls having a diameter of 0.1 mm), and then the average pore diameter After filtering with a 1.2 μm membrane filter, 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 26 of Pigment Dispersion)
-Preparation of Pigment Dispersions PD-2 to 26-
Pigment Dispersions PD-2 to 26 were obtained in the same manner as in Pigment Dispersion Preparation Example 1 except that the composition was changed to that shown in Table 4 below.

In Table 4, the following products were used as pigments other than carbon black.
Pigment Blue 15:3 (Chromofine Blue A-220JC, manufactured by Dainichiseika Kogyo Co., Ltd.)
Pigment Red 122 (Toner Magenta EO02, manufactured by Clariant Japan Co., Ltd.)
・Pigment Yellow 74 (First Yellow 531, manufactured by Dainichiseika 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-dimethylpropione 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 were mixed and stirred for 1 hour, and then filtered through a membrane filter having an average pore diameter of 1.2 μm to obtain the ink GJ-1 of Example 1. It was made.

(Examples 2 to 26)
-Preparation of Inks GJ-2 to 26-
Inks GJ-2 to 26 of Examples 2 to 26 were prepared in the same manner as in Example 1 except that the ink compositions shown in Tables 5 and 6 below were changed.

(Comparative Example 1)
-Preparation of comparative ink RGJ-1-
A monomer solution was prepared by dissolving 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 (1) in 30 mL of dry methyl ethyl ketone. After heating 10% by mass of the monomer solution to 75° C. under an argon stream, a solution in which 0.556 g of 2,2-azobis(isobutyronitrile) was dissolved in the remaining monomer solution was 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 added to hexane. The precipitated copolymer was separated by filtration and dried under reduced pressure to obtain 14.11 g of comparative copolymer RCP-1 (weight average molecular weight (Mw): 12,500).

Then, using this, in the same manner as in Example 1, a 10 mass% aqueous solution of the comparative copolymer RCP-1 was prepared.
Next, as in Preparation Example 1 of the pigment dispersion, except that the 10 mass% aqueous solution of the copolymer CP-1 in Preparation Example 1 of the pigment dispersion was changed to the 10 mass% aqueous solution of the comparative copolymer RCP-1. The 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 pigment dispersion PD-1 in the preparation of the ink of Example 1 was changed to the comparative pigment dispersion RPD-1.

(Comparative example 2)
-Preparation of comparative ink RGJ-2-
Except that the 10 mass% aqueous solution of the copolymer CP-1 in Preparation Example 19 of the pigment dispersion was changed to the 10 mass% aqueous solution of the comparative copolymer RCP-1, the same procedure as in Preparation example 19 of the pigment dispersion was carried out. Comparative pigment dispersion RPD-2 was obtained.
Next, a comparative ink RGJ-2 was obtained in the same manner as in Example 19 except that the pigment dispersion PD-19 in the preparation of the ink of Example 19 was changed to the comparative pigment dispersion RPD-2.

(Comparative example 3)
-Preparation of comparative ink RGJ-3-
Except that the 10 mass% aqueous solution of the copolymer CP-1 in Preparation Example 20 of the pigment dispersion was changed to the 10 mass% aqueous solution of the comparative copolymer RCP-1, the same procedure as in Preparation Example 20 of the pigment dispersion was carried out. Comparative pigment dispersion RPD-3 was obtained.
Next, Comparative Ink RGJ-3 was obtained in the same manner as Example 20 except that the pigment dispersion PD-20 in the preparation of the ink of Example 20 was changed to the comparative pigment dispersion RPD-3.

(Comparative Example 4)
-Preparation of comparative ink RGJ-4-
Except that the 10% by mass aqueous solution of the copolymer CP-1 in Preparation Example 21 of the pigment dispersion was changed to the 10% by mass aqueous solution of the comparative copolymer RCP-1, the same procedure as in Preparation Example 21 of the pigment dispersion was carried out. Comparative pigment dispersion RPD-4 was obtained.
Next, a comparative ink RGJ-4 was obtained in the same manner as in Example 21 except that the pigment dispersion PD-21 in the ink preparation of Example 21 was changed to the comparative pigment dispersion RPD-4.

(Comparative example 5)
-Preparation of Comparative 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 were added to tetrahydrofuran ( THF) (160 mL), and heated to 65° C. in a nitrogen atmosphere and reacted for 7 hours. 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 heating to 50° C. and reacting for 2.5 hours, reprecipitation was performed with a mixed solvent of methanol and water for purification, and 71 g of macromonomer MM-1 (weight average molecular weight (Mw): 4,000, The 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 A solution of p-styrenesulfonic acid (4) and 49.2 g of methyl methacrylate dissolved in 40 g of methyl ethyl ketone was added dropwise over 3 hours. After completion of the dropping, the reaction was continued for another 1 hour, then a solution of 0.2 g of dimethyl 2,2′-azobisisobutyrate 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 obtained reaction solution was dropped into hexane, and the precipitated graft polymer was separated by filtration and dried to obtain a comparative copolymer RCP-5 (weight average molecular weight (Mw): 22,000). ..

-Preparation of Comparative Pigment Dispersion RPD-5-
Then, in the same manner as in Preparation example 1 of pigment dispersion, except that the 10 mass% aqueous solution of the copolymer CP-1 in Preparation example 1 of pigment dispersion was changed to a 10 mass% aqueous solution of the comparative copolymer RCP-5. Thus, 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 the pigment dispersion PD-1 in the preparation of the ink of Example 1 was changed to the comparative pigment dispersion RPD-5.

(Comparative example 6)
-Synthesis of Comparative Copolymer RCP-6-
72.0 g (500 mmol) of 2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.), 125.0 g (1,000 mmol) of ethylene glycol mono-2-chloroethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.), 500 mL of N -Methyl-2-pyrrolidinone (manufactured by Kanto Chemical Co., Inc.) was dissolved 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 obtained reaction solution, and the mixture was 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 by the above reaction, 45.0 g (450 mmol) of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was 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. 250 mL of ethyl acetate and 100 mL of pure water were added to the obtained solution 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 evaporated. The residue was purified by silica gel column chromatography to obtain 80.5 g of the monomer of the following structural formula (2).

Next, 12.0 g of methyl ethyl ketone was added to a 100 mL three-necked flask equipped with a stirrer and a cooling tube, and heated to 72° C. under an argon stream. Here, 2.4 g (8.00 mmol) of the monomer of the structural formula (2), 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. A solution in which benzyl acidate (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. Was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was further reacted for 1 hour, and a solution prepared by dissolving 0.06 g (0.26 mmol) of dimethyl 2,2′-azobis(isobutyrate) in 2.0 g of methyl ethyl ketone was added and heated to 78° C. Stir for hours. After that, reprecipitation was repeated twice with 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-6 (weight average molecular weight (Mw): 34,000).

-Preparation of Comparative Pigment Dispersion RPD-6-
4.0 parts by mass of the comparative copolymer RCP-6 was mixed with 1.9 parts by mass of a 35% by mass tetraethylammonium hydroxide 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-exchanged water to obtain an aqueous solution of comparative copolymer RCP-6.
To an aqueous solution of 84.0 parts by mass of the comparative copolymer RCP-6, 16.0 parts by mass of carbon black (NIPEX150, manufactured by Degussa) was 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 (KDL type, manufactured by Shinmaru Enterprises Co., Ltd., media: zirconia balls having a diameter of 0.1 mm) was used, and then the average pore diameter was obtained. 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 comparative pigment dispersion RPD-6 (pigment solid content concentration: 16% by mass).

-Preparation of Comparative 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 concentration: 100% by mass), and 37.0 parts by mass of ion-exchanged water was mixed, stirred for 1 hour, and then filtered through a membrane filter having an average pore size of 1.2 μm to obtain comparative ink RGJ-6.

Next, various properties of the produced pigment dispersions and inks of Examples 1 to 26 and Comparative Examples 1 to 6 were evaluated as follows. The results are shown in Table 7 below.

<Storage stability of pigment dispersion>
Each pigment dispersion was filled in a glass container having a volume of 30 mL in an amount of 15 mL and stored at 70° C. for 2 weeks. The rate of change in viscosity after storage with respect to the viscosity before storage was obtained from the following formula and evaluated according to the following criteria. In addition, C or more is practical.
A viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used to measure the viscosity, and the viscosity at 25° C. was measured at 50 rotations.
〔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: Viscosity change rate exceeds ±10%, within ±30% E: Viscosity change rate exceeds ±30% (gelation cannot be evaluated)

<Ink storage stability>
Each ink was filled in an ink container and stored at 70° C. for 1 week. The rate of change in viscosity after storage with respect to the viscosity before storage was obtained from the following formula, and evaluated according to the following criteria. In addition, C or more is practical.
A viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used to measure the viscosity, and the viscosity at 25° C. was measured at 50 rotations.
〔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: Viscosity change rate exceeds ±10%, within ±30% E: Viscosity change rate exceeds ±30% (gelation cannot be evaluated)

<Image density>
In the environment of 23° C. and 50% RH, an ink jet printer (manufactured by Ricoh Co., Ltd., IPSiO GX5000) was filled with each ink, and 64 points of JIS X 0208 (1997), 2223 created by Microsoft Word 2000 (manufactured by Microsoft) were used. A chart with general symbols is stamped on plain paper 1 (XEROX4200, manufactured by XEROX Co., Ltd.) and plain paper 2 (MyPaper, manufactured by Ricoh Co., Ltd.), and the symbol portion on the printed surface is marked with X-Rite 938 (X-light (Manufactured by the company), and the color was evaluated according to the following criteria. In addition, C or more is practical.
As the printing mode, a mode in which the "plain paper-standard fast" mode was changed to "no color correction" from the user setting for plain paper using a driver attached to the printer was used.
The general symbols of JIS X 0208 (1997) and 2223 are symbols in which the outer shape is a square shape 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 is gelled and cannot be dispersed in the ink. Cannot print

From the results in Table 7 above, the pigment dispersions prepared using the copolymers having naphthyl groups at the ends of the side chains of Examples 1 to 26 have no naphthyl groups at the ends of the side chains of Comparative Examples 1 to 5. It had excellent storage stability as compared with the pigment dispersion prepared by using the copolymer. It is considered that this is because the naphthyl group of the copolymer and the π-π interaction between the pigment increased the adsorptivity to the pigment.
Further, as in Comparative Example 6, even if it has a naphthyl group at the terminal of the side chain, depending on the selection of other monomers used in the synthesis of the copolymer, the storage stability of the ink may be sufficient. It was difficult to guarantee stable quality over a long period of time.

The aspects 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).
However, 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 6 to 6 carbon atoms containing a substituted or unsubstituted aromatic ring. Represents 15 hydrocarbon groups.
In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl radical, n is. 1 to 90, m is an integer of 0-90.
<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 (3).
However, in the general formula (3), 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 40% by mass or more and 70% by mass or less. is there.
<4> The ink according to any one of <1> to <3>, wherein the structural unit represented by the general formula (1) is one 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 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 color material is a pigment.
<10> The ink according to any one of <1> to <9>, further containing 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, wherein the copolymer is synthesized by radical polymerization from a polymerizable material containing a monomer represented by the following general formula (4) and a monomer represented by the following general formula (5). Is the way.
However, in the general formula (4), R ₄ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, and Y represents 6 to 6 carbon atoms including a substituted or unsubstituted aromatic ring. Represents 15 hydrocarbon groups.
In the general formula (5), _{R 5} and _{R 6} represent a hydrogen atom or a methyl radical, n is. 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 (4) is any of the monomers represented by the following structural formulas.
<13> The monomer represented by the general formula (5) is at least one selected from methoxy polyethylene glycol methacrylate, polyethylene glycol monomethacrylate, methoxy polyethylene glycol monoacrylate, and polyethylene glycol polypropylene glycol monomethacrylate. 11> The method for producing an ink according to any one of <12>.
<14> An ink storage container including an ink storage portion that stores ink,
It is an ink container characterized in that the ink contained in the ink container is the ink according to any one of <1> to <10>.
<15> An image forming method, which also includes an ink flying step of applying a stimulus to the ink according to any one of <1> to <10> to fly the ink to 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: an ink flying unit that applies a stimulus to the ink according to any one of <1> to <10> to fly 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 a recording layer on a recording medium,
The recording layer contains a coloring material and a copolymer,
The image-formed product 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).
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, carbon atoms Y is including substituted or unsubstituted aromatic ring It represents a hydrocarbon group of 6 to 15.
In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl radical, n is. 1 to 90, m is an integer of 0-90.
<20> The image forming material 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>, the <15>. To <16>, the image forming apparatus described in <17> to <18>, and the image formed product described in <19> to <20>. According to this, it is possible to solve the above-mentioned various problems in the related art and achieve the above-mentioned object of the present invention.

400 image forming apparatus

JP, 2011-105866, A

Claims (11)

An ink containing water, a coloring material, and 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).
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, carbon atoms Y is including substituted or unsubstituted aromatic ring It represents a hydrocarbon group of 6 to 15.
In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl radical, n is. 1 to 90, m is an integer of 0-90. 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 (3).
However, in the general formula (3), R ₂ and R ₃ represent a hydrogen atom or a methyl group, and 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 claim 1, 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 claim 1, 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,
A step of synthesizing a copolymer by radical polymerization from the polymerizable material comprising a monomer represented by the monomer represented by the following general formula (5) under following general formula (4),
Water, a coloring material, and a step of dispersing and stirring the copolymer,
A method for producing an ink , comprising :
In the general formula (4), R ₄ represents a hydrogen atom or a methyl group, X represents an alkylene group having 2 to 4 carbon atoms, carbon atoms Y is including substituted or unsubstituted aromatic ring It represents a hydrocarbon group of 6 to 15.
In the general formula (5), _{R 5} and _{R 6} represent a hydrogen atom or a methyl radical, n is. 1 to 90, m is an integer of 0-90. An ink containing container having an ink containing portion for containing ink,
An ink container, 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: an ink flying step of applying a stimulus to the ink according to any one of claims 1 to 6 to fly the ink to record an image. The ink according to any one of claims 1 to 6 ,
An inkjet head for ejecting the ink,
An image forming apparatus comprising: An image formed product having a recording layer on a recording medium,
The recording layer contains a coloring material and a copolymer,
An image-formed product, wherein the copolymer contains a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2).
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, carbon atoms Y is including substituted or unsubstituted aromatic ring It represents a hydrocarbon group of 6 to 15.
In the general formula (2), _{R 2} and _{R 3} represents a hydrogen atom or a methyl radical, n is. 1 to 90, m is an integer of 0-90.