JP6197494B2 - Ink jet recording ink, ink cartridge, ink jet recording method, and ink jet recording apparatus - Google Patents

Description

  The present invention relates to an ink for ink jet recording, an ink cartridge, an ink jet recording method, and an ink jet recording apparatus.

When a pigment is used as a colorant in an inkjet recording ink (hereinafter also referred to as “ink”), if a normal hydrocarbon-based activator is used, the uniformity of the solid image portion, color developability, etc. It is difficult to achieve the same level as dye ink. For this reason, it is already known that by using a fluorine-based material as the surfactant, the surface tension of the ink can be lowered, the uniformity of the solid image portion can be raised, and the color development can be improved.
However, conventional fluorosurfactants can achieve high-quality image formation, but have an environmental impact, or have a low environmental impact, but cannot provide high-quality image quality, reducing environmental impact and improving image quality. There is a problem that it is difficult to coexist with the foam and the bubbles are difficult to disappear.
For example, for the purpose of forming a high-quality image on plain paper, an ink for inkjet recording to which a specific fluorine-based surfactant and a foam suppressor are added has been proposed (see Patent Document 1).
However, although the proposed technology can reduce the environmental load, it is not sufficient in terms of high-quality image formation (high color development), and achieves both a reduction in environmental load and an improvement in image quality. This is difficult at present.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide an ink for inkjet recording that has a low environmental load, has high defoaming properties, and can improve image quality.

The ink for ink jet recording of the present invention as means for solving the above problems is water, a water-soluble organic solvent, a colorant, a compound having a group represented by the following structural formula (1), and the following general formula (1) The compound represented by this is contained.
_{C 6 F 13 -CH 2 CH 2} - ··· structural formula (1)
_{HO-R 1 R 3 C- [} CH 2] n -CR 2 R 4 -OH ··· formula (1)
In the general formula (1), _{R 1} and _{R 2} each independently represent an alkyl group having 3 to 6 carbon atoms, _{R 3} and _{R 4} are each independently an alkyl group having 1 to 2 carbon atoms N is an integer of 1-6.

  According to the present invention, it is possible to solve the above-described problems, and to provide an ink for ink jet recording that has low environmental load, high defoaming properties, and improved image quality.

FIG. 1 is a schematic view showing an example of the ink cartridge of the present invention. FIG. 2 is a schematic view including the case of the ink cartridge of FIG. FIG. 3 is an explanatory perspective view of the ink jet recording apparatus in a state where the cover of the ink cartridge loading unit is opened. FIG. 4 is a schematic configuration diagram illustrating the overall configuration of the ink jet recording apparatus.

(Inkjet recording ink)
The ink for inkjet recording of the present invention contains water, a water-soluble organic solvent, a colorant, a compound having a group represented by the following structural formula (1), and a compound represented by the following general formula (1). Further, it contains other components as required.
_{C 6 F 13 -CH 2 CH 2} - ··· structural formula (1)
_{HO-R 1 R 3 C- [} CH 2] n -CR 2 R 4 -OH ··· formula (1)
In the general formula (1), _{R 1} and _{R 2} each independently represent an alkyl group having 3 to 6 carbon atoms, _{R 3} and _{R 4} are each independently an alkyl group having 1 to 2 carbon atoms N is an integer of 1-6.

The compound having a group represented by the structural formula (1) is preferably a compound represented by the following general formula (2).
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· formula (2)
However, in said general formula (2), n is a natural number of 1-40.

In the present invention, a compound having a group represented by the structural formula (1) (fluorine-based surfactant) and a compound represented by the general formula (1) (foam suppressor) are used in combination. In addition, it is possible to provide an ink that can achieve both reduction in environmental burden and image quality (particularly high color developability). In addition, ejection instability caused by the foaming of the fluorosurfactant can be suppressed.
By containing the compound having the group represented by the structural formula (1) in a specific ratio in the ink, the surface tension is lower than that of the conventional ink, but the surface tension is low. In addition to the characteristics of the conventional ink in which the vehicle quickly penetrates into the paper and the colorant tends to remain on the surface, further coloration can be achieved by using the compound having the group represented by the structural formula (1). The uneven distribution of the agent is eliminated, and the leveling property is remarkably improved by the presence of the colorant uniformly on the paper surface. As a result, an image with high saturation and high color density, but with little show-through is obtained. Further, ejection instability due to the high foaming property, which is a feature of the fluorosurfactant, can be suppressed by adding the compound represented by the general formula (1).
Here, the fluorosurfactant (Zonyl FS-300, manufactured by DuPont) represented by the following general formula (3) has a perfluoroalkyl group having 8 carbon atoms, and in the production process, PFOA (perfluorooctane) is used. Acid) as a by-product. It has been pointed out that this PFOA is carcinogenic.
_{C 8 F 17 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· formula (3)
However, in said general formula (3), n represents the natural number of 1-40.

  On the other hand, since the compound having the group represented by the structural formula (1) has a perfluoroalkyl group having 6 carbon atoms, PFOA is not generated as a by-product during synthesis. Reduced.

<Compound having a group represented by the structural formula (1)>
The compound having a group represented by the structural formula (1) can improve image quality (high color developability, etc.) and impart wettability to a member due to a decrease in surface tension.
The compound having a group represented by the structural formula (1) is preferably a compound represented by the following general formula (2).
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· formula (2)
In the general formula (2), n is preferably a natural number of 1 to 40, and more preferably 6 to 30.
The perfluoroalkyl group C ₆ F ₁₃ in the general formula (2) is preferably a straight chain from the viewpoint of wettability to the member.
As the compound represented by the general formula (2), an appropriately synthesized compound or a commercially available product may be used. Examples of the commercially available products include CAPSTONE (Capstone, registered trademark) FS-30, FS-34, and FS-3100 manufactured by DuPont.

In addition to the compound having a group represented by the structural formula (1), other surfactants may be used in combination. In that case, the ratio of the compound having the group represented by the structural formula (1) to the total content of the compound having the group represented by the structural formula (1) and the other surfactant is 60% by mass or more. It is preferable that
The other surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include nonionic surfactants, anionic surfactants, acetylene glycol surfactants, and fluorine surfactants. Agents, amphoteric surfactants, and the like.
Examples of the nonionic surfactant include Marpomace PT manufactured by Matsumoto Yushi Co., Ltd.
Examples of the anionic surfactant include ECTD-3NEX manufactured by Nikko Chemicals.
Examples of the acetylene glycol surfactant include Surfynol 104PA manufactured by Air Products Japan.
Examples of the fluorosurfactant include DuPont Zonyl FS-300, FSN, FSN-100, FSO, FSO-100, FSH, and Daikin DSN-403N.

The content of the compound having a group represented by the structural formula (1) (preferably a compound represented by the general formula (2)) is not particularly limited and can be appropriately selected according to the purpose. 0.05 mass%-5.0 mass% are preferable with respect to the said inkjet recording ink whole quantity, and 0.1 mass%-0.5 mass% are more preferable. Within this numerical range, the surface tension of the ink can be reduced and the vehicle can be rapidly penetrated to leave the colorant on the paper.
When the content is less than 0.05% by mass, the effect of high color developability may not be obtained. When the content exceeds 5.0% by mass, the storage stability of the ink may be deteriorated. .

<Compound represented by general formula (1) (foam suppressor)>
The compound represented by the following general formula (1) is used for suppressing foaming by adding a trace amount to the ink for ink jet recording.
_{HO-R 1 R 3 C- [} CH 2] n -CR 2 R 4 -OH ··· formula (1)
In the general formula (1), _{R 1} and _{R 2} each independently represent an alkyl group having 3 to 6 carbon atoms, _{R 3} and _{R 4} are each independently an alkyl group having 1 to 2 carbon atoms N is an integer of 1-6.

Here, foaming means that the liquid becomes a thin film and wraps air. The generation of the bubbles involves characteristics such as surface tension and viscosity of the ink for ink jet recording. That is, a liquid having a high surface tension such as water is difficult to foam because a force that attempts to make the surface area of the liquid as small as possible works. On the other hand, inks for ink jet recording with high viscosity and high permeability tend to foam due to low surface tension, and bubbles generated due to the viscosity of the solution are easily maintained and are difficult to defoam.
Usually, the foam suppressor destroys the foam by locally lowering the surface tension of the foam film to destroy the foam or by interspersing the foam suppressor with a foam suppressor insoluble in the foam liquid. When an extremely strong fluorosurfactant that lowers surface tension is used as a surfactant for ink jet recording ink, the surface tension of the foam film is locally reduced even if the former foam suppressor is used. Since it cannot be lowered, it is not usually used. For this reason, an antifoaming agent that is insoluble in the latter foaming liquid is used. In this case, the stability of the ink for ink jet recording may be reduced by the antifoaming agent insoluble in the solution.
Although the compound (foam suppressor) represented by the general formula (1) is not as strong as the fluorosurfactant in reducing the surface tension, it has high compatibility with the fluorosurfactant. For this reason, when the foam is efficiently incorporated into the foam film, the surface of the foam film is locally unbalanced due to the difference in surface tension between the fluorosurfactant and the foam suppressor, and the foam is destroyed. Conceivable.

  Examples of the compound represented by the general formula (1) include 2,4,7,9-tetramethyldecane-4,7-diol, 2,5,8,11-tetramethyldodecane-5,8- Diol, and the like. Among these, 2,5,8,11-tetramethyldodecane-5,8-diol is particularly preferable because of its high antifoaming effect and high compatibility with ink.

  The content of the compound represented by the general formula (1) in the ink for inkjet recording is preferably 0.05% by mass to 1.0% by mass. If the content is less than 0.05% by mass, the effect of suppressing foam may not be obtained. If the content exceeds 1.0% by mass, the foam-suppressing effect reaches its peak, and the viscosity, Ink physical properties such as diameter may be adversely affected.

<Water>
There is no restriction | limiting in particular as said water, According to the objective, it can select suitably, For example, pure water, such as ion-exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water etc. are mentioned. It is done. These may be used individually by 1 type and may use 2 or more types together.

<Water-soluble organic solvent>
The water-soluble organic solvent is contained in the ink to prevent drying and improve dispersion stability.
The water-soluble organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, Examples include amides, amines, sulfur-containing compounds, propylene carbonate, ethylene carbonate, and other organic solvents. These may be used individually by 1 type and may use 2 or more types together. The water-soluble organic solvent may be referred to as a wetting agent.

  Examples of the polyhydric alcohols include glycerin, diethylene glycol, 1,3-butanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, triethylene glycol, propylene glycol, Dipropylene glycol, trimethylolethane, trimethylolpropane, ethylene glycol, tripropylene glycol, tetraethylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,2 , 6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol, and the like.

Examples of the polyhydric alcohol alkyl ethers include 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 ether, and the like. Can be mentioned.
Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, Etc.
Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide, and the like.
Examples of the amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine, and the like.
Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like.

Examples of the other organic solvents include saccharides. Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and the like.
Examples of the monosaccharide, disaccharide, and oligosaccharide (including trisaccharide and tetrasaccharide) include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose. , Etc.
The polysaccharide means a saccharide in a broad sense and includes α-cyclodextrin, cellulose and the like.
Examples of the saccharide derivatives include reducing sugars of the saccharides (for example, sugar alcohols represented by the general formula: HOCH ₂ (CHOH) _n CH ₂ OH (n = 2 to an integer of 2 to 5)), oxidized sugars (for example, Aldonic acid, uronic acid, etc.), amino acids, thioic acids, and the like. Of these, sugar alcohols are particularly preferred.
Examples of the sugar alcohol include maltitol, sorbitol, xylitol, and the like.
Among the water-soluble organic solvents, glycerin, hexylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, and 2-ethyl are used from the viewpoint of ink storage stability and ejection stability. -1,3-hexanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 1,5-pentanediol, 1,6-hexanediol, trimethylolpropane, tetramethylol Propane, D-sorbitol, xylitol and 2-pyrrolidone are preferred, 1,3-butanediol, glycerin, 2-ethyl-1,3-hexanediol, 3-methyl-1,3-butanediol, hexylene glycol, 3 -Methyl-1,5-pentanediol, 2- Pyrrolidone, 1,5-pentanediol, 1,6-hexanediol are more preferred.

The content of the water-soluble organic solvent in the ink jet recording ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass to 50% by mass, and 15% by mass to 40% by mass. Is more preferable. If it is within the preferable numerical range, the results such as the drying property, storage stability and reliability of the ink are very good.
In the case of pigment ink, the ratio of the pigment to the water-soluble organic solvent greatly affects the ejection stability of the ink from the head. If the pigment solid content ratio is high but the blending amount of the water-soluble organic solvent is small, water evaporation near the ink meniscus of the nozzle proceeds, resulting in ejection failure.

<Colorant>
As the colorant, a dye or a pigment can be used, but a pigment is preferable from the viewpoint of water resistance and light resistance of an ink recorded matter. There is no restriction | limiting in particular as a kind of said pigment, According to the objective, it can select suitably, An organic pigment, an inorganic pigment, etc. are mentioned. These pigments may be used alone or in combination as a mixture.
Examples of the organic pigment include azo, phthalocyanine, anthraquinone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, and rhodamine B lake pigments.
Examples of the inorganic pigment include carbon black, iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, and metal powder.

Examples of the black pigment include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper oxide, iron oxide (CI pigment black 11). And organic pigments such as metals such as titanium oxide and aniline black (CI Pigment Black 1).
Specific examples of yellow pigments include C.I. I. Pigment Yellow 1 (Fast Yellow G), 2, 3, 12 (Disazo Yellow AAA), 13, 14, 16, 17, 20, 23, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55 73, 74, 75, 81, 83 (disazo yellow HR), 86, 93, 95, 97, 98, 100, 101, 104, 108, 109, 110, 114, 117, 120, 125, 128, 129, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185 and the like.

  Examples of magenta pigments include C.I. I. Pigment violet 19, C.I. I. Pigment Red 1, 2, 3, 5, 7, 9, 12, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 1 [Permanent Red 2B (Ba)], 48: 2 [Permanent Red 2B (Ca)], 48: 3 [permanent red 2B (Sr)], 48: 4 [permanent red 2B (Mn)], 49: 1, 52: 2, 53: 1, 57: 1 (brilliant carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 92, 97, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 (dimethylquinacridone), 123, 146, 149, 166, 168, 170, 172, 175, 176, 178, 179, 180 184,185,190,192,193,202,209,215,216,217,219,220,223,226,227,228,238,240,254,255,272, and the like.

Examples of cyan pigments include C.I. I. Pigment Blue 1, 2, 3, 15 (copper phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 22, 56, 60, 63, 64, Bat Blue 4, Bat Blue 60, and the like.
Specific examples of the intermediate color pigment include C.I. for red, green and blue. I. Pigment red 177, 194, 224, C.I. I. Pigment orange 16, 36, 43, 51, 55, 59, 61, 71, C.I. I. Pigment violet 3, 19, 23, 29, 30, 37, 40, 50, C.I. I. Pigment green 7, 36, and the like.

The following first to third forms are particularly preferred when the colorant is a pigment.
(1) In the first embodiment, the colorant has a pigment having at least one hydrophilic group on its surface and can be self-dispersed in aqueous ink in the absence of a dispersant (hereinafter referred to as “self-dispersing pigment”). Sometimes called).
(2) In the second embodiment, the colorant contains a polymer emulsion (an aqueous dispersion of a pigment coated with a polymer) in which polymer fine particles contain a colorant that is insoluble or hardly soluble in water.
(3) In the third embodiment, the colorant is a pigment dispersed with a surfactant.

The self-dispersing pigment of the first form is surface-modified so that at least one hydrophilic group is bonded to the surface of the pigment directly or through another atomic group.
In the surface modification, a specific functional group (a functional group such as a sulfone group or a carboxyl group) is chemically bonded to the surface of the pigment, or at least one of hypohalous acid and a salt thereof is used. A method such as wet oxidation is used.
For example, as the self-dispersing carbon black, those having ionicity are preferable, and those having an anionic charge or those charged in a cationic form are suitable. Examples of the anionic hydrophilic group include —COOM, —SO ₃ M, —PO ₃ HM, —PO ₃ M ₂ , —SO ₂ NH ₂ , —SO ₂ NHCOR (where M is a hydrogen atom, an alkali metal) And R represents an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent.
Among these, it is preferable to use those in which —COOM and —SO ₃ M are bonded to the surface of the color pigment. Among these, the self-dispersing pigment in which —COOM is bonded to the surface of the pigment and dispersed in water not only improves the dispersion stability, but also provides high-quality printing quality and recording after printing. The water resistance of media is improved. Further, “M” in the hydrophilic group includes, for example, lithium, sodium, potassium and the like as an alkali metal. Examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium.

  As a method of obtaining the anionically charged color pigment, as a method of introducing —COONa to the color pigment surface, for example, a method of oxidizing the color pigment with sodium hypochlorite, a method of sulfonation, a diazonium salt The method of making it react is mentioned. As the cationic hydrophilic group, for example, a quaternary ammonium group is preferable, and those bonded to the carbon black surface are preferable. The volume average particle size of the self-dispersing pigment is preferably 0.01 μm to 0.16 μm in the ink.

  As the pigment coated with the polymer of the second form, it is preferable to use a polymer emulsion in which a pigment is contained in polymer fine particles in addition to the pigment. The polymer emulsion in which the pigment is contained in the polymer fine particles is one in which the pigment is encapsulated in the polymer fine particles, or the pigment is adsorbed on the surface of the polymer fine particles. In this case, it is not necessary that all the pigments are encapsulated or adsorbed, and the pigments may be dispersed in the emulsion as long as the effects of the present invention are not impaired. Examples of the polymer forming the polymer emulsion (polymer in the polymer fine particles) include vinyl polymers, polyester polymers, and polyurethane polymers. Among these, a water-insoluble vinyl polymer is particularly preferable.

<< Water-insoluble vinyl polymer >>
The water-insoluble vinyl polymer includes (A) a monomer represented by the following general formula (VI) [hereinafter also referred to as monomer (A)], (B) a salt-forming group-containing monomer [hereinafter referred to as monomer (B) And (C) a hydrophobic monomer (hereinafter also referred to as monomer (C)). As necessary, these monomers may be mixed with the required amount of each monomer to form a composition, or monomers other than the monomers (A), (B), and (C) can be additionally used.

[General formula (VI)]

In the general formula (VI), R ₁ is preferably a hydrogen atom or a methyl group from the viewpoint of polymerizability. R ₂ is an alkylene group having 2 to 8 carbon atoms or an alkylene group having 2 to 4 carbon atoms in which a hydrogen atom is substituted with a phenyl group, but an ethylene group, propylene group or butylene group having 2 to 4 carbon atoms. Is preferred. n is an average added mole number, and is a number of 2 to 30, but from the viewpoint of printing density and storage stability, a number of 2 to 25 is preferable, a number of 2 to 15 is more preferable, and 2 to 10 is preferable. Numbers are particularly preferred.
The n R _{2 s} may be the same or different, and when they are different, either block addition or random addition may be used.
R ₃ is a linear or branched alkyl group having 2 to 30 carbon atoms, preferably an alkyl group having 2 to 22 carbon atoms from the viewpoint of high printing density and good storage stability, and has 8 to 18 carbon atoms. Are more preferable, and an octyl group, 2-ethylhexyl group, decyl group, dodecyl (lauryl) group, tetradodecyl (myristyl) group, hexadecyl (cetyl) group and octadecyl (stearyl) group are particularly preferable.

  The monomer (A) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include octoxypolyethylene glycol mono (meth) acrylate, octoxypoly (ethylene glycol / propylene glycol) mono (meth) acrylate, Octoxy poly (ethylene glycol / butylene glycol) mono (meth) acrylate, Lauroxy polyethylene glycol (meth) acrylate, Lauroxy poly (ethylene glycol / propylene glycol) mono (meth) acrylate, stearoxy polyethylene glycol mono (meth) acrylate, stearoxy poly (Ethylene glycol / propylene glycol) mono (meth) acrylate and the like. These may be used individually by 1 type and may use 2 or more types together.

  By using the monomer (A), there is an advantage that a water-based ink having a high printing density and excellent storage stability can be obtained. The terminal alkyl group of the monomer (A) has an effect of facilitating the retention of the colorant on the paper surface and imparts excellent dispersion stability to the water-based ink. In addition, since the monomer (A) exhibits high compatibility with a specific water-soluble organic solvent, when the specific water-soluble organic solvent is contained in the ink, the water evaporates to reach an equilibrium state. Even in the ink residue that has been reached, dispersion stability can be imparted to the polymer particles.

The monomer (A) is obtained by a method in which an aliphatic alcohol terminal (—OH) is polymerized with an alkylene oxide and the polymerized terminal group (—OH) is etherified.
Specific examples of the commercially available monomer (A) include Kyoeisha Chemical Co., Ltd. Light Acrylate EA-C, Nippon Oil & Fats Co., Ltd. 50POEP-800B, PLE200, PSE-400, and the like.
The content of the monomer (A) in the monomer mixture used for polymerizing the water-insoluble vinyl polymer is preferably 3% by mass to 25% by mass from the viewpoint of printing density and ink viscosity, and 5% by mass to 20% by mass. % Is more preferable.

As the monomer (B), a salt-forming group-containing monomer is used. In this embodiment, the salt-forming group monomer refers to a monomer having a salt-forming group that forms a salt by a neutralization reaction.
Examples of the salt-forming group-containing monomer suitably used in the present embodiment include an anionic monomer having an anion-generating group.
The anion-generating group generates an anion in water and imparts dispersion stability to the polymer dispersion by electrostatic repulsion, and when the ink lands on the recording medium, it loses electrostatic repulsive force due to pH change, Promotes pigment fixation. These may be used individually by 1 type and may use 2 or more types together.
Examples of the anionic monomer include one or more selected from an unsaturated carboxylic acid monomer, an unsaturated sulfonic acid monomer, and an unsaturated phosphoric acid monomer.
Examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethyl succinic acid. These may be used individually by 1 type and may use 2 or more types together.
Examples of the unsaturated sulfonic acid monomer include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3-sulfopropyl (meth) acrylic acid ester, bis- (3-sulfopropyl) -itaconic acid ester, and the like. Is mentioned. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the unsaturated phosphoric acid monomer include vinyl phosphonic acid, vinyl phosphate, bis (methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2- Examples include acryloyloxyethyl phosphate. These may be used individually by 1 type and may use 2 or more types together.

Among the anionic monomers, unsaturated carboxylic acid monomers are preferable, and acrylic acid and methacrylic acid are more preferable from the viewpoint of printing density and storage stability.
The content of the monomer (B) in the monomer mixture used for polymerizing the water-insoluble vinyl polymer is preferably 3% by mass to 25% by mass from the viewpoint of printing density and storage stability, and 5% by mass to 20%. % By mass is more preferable, and 12% by mass to 14% by mass is even more preferable.
When the content of the monomer (B) is less than 3% by mass, there is a problem that it is difficult to dissolve in the basic substance and it is difficult to coat the pigment.

  As the monomer (C), a hydrophobic monomer is used in order to impart water resistance to the recorded matter. As the monomer (C) suitably used in the present embodiment, (C-1) a monomer represented by the following general formula (VII), (C-2) a monomer represented by the following general formula (VIII), (C-3) Macromers are mentioned.

<General formula (VII)>
In the general formula (VII), _{R 4} is a hydrogen atom or a methyl group, _{R 5} is an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 22 carbon atoms, alkylaryl group or arylalkyl Group or a C3-C22 cyclic hydrocarbon group is shown.

<General formula (VIII)>
In the general formula (VIII), R ₆ represents a hydrogen atom or a methyl group, R ₇ is a phenyl group which may have a substituent or a biphenyl group, or a naphthalene group. These may be used individually by 1 type and may use 2 or more types together.

The monomer (C) preferably contains at least one selected from (C-2) an aromatic ring-containing monomer and (C-3) a macromer from the viewpoint of printing density and scratch resistance.
As the monomer having an alkyl group of (C-1), a monomer having R ⁴ as a methyl group is preferable, and methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, (iso or tarsic). Lee) Butyl (meth) acrylate, (iso) amyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) decyl (meth) acrylate, (iso) dodecyl (meth) (Meth) acrylates in which the ester moiety such as acrylate, (iso) stearyl (meth) acrylate, behenyl (meth) acrylate and the like is an alkyl group having 1 to 22 carbon atoms may be mentioned. These may be used individually by 1 type and may use 2 or more types together.
In addition, said (iso or tertiary) and (iso) mean both the case where these groups exist, and the case where it is not so, and when these groups do not exist, it shows normal. (Meth) acrylate means both methacrylate and acrylate. The same applies to the following.

Examples of the monomer (C-1) having an aryl group include benzyl (meth) acrylate and phenoxyethyl (meth) acrylate. These may be used individually by 1 type and may use 2 or more types together.
The monomer having a cyclic hydrocarbon group (C-1) is a monocyclic, bicyclic, or tricyclic or higher polycyclic (meth) acrylate having 3 or more carbon atoms. Specifically, examples of the monocyclic (meth) acrylate having 3 or more carbon atoms include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and cycloheptyl. (Meth) acrylate, cyclooctyl (meth) acrylate, cyclononyl (meth) acrylate, cyclodecyl (meth) acrylate, etc. are mentioned.
Examples of the bicyclic (meth) acrylate include isobornyl (meth) acrylate and norbornyl (meth) acrylate.
Examples of the tricyclic (meth) acrylate include adamantyl (meth) acrylate.
These may be used individually by 1 type and may use 2 or more types together.
Among these, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, and adamantyl (meth) acrylate are preferable from the viewpoint of storage stability.

The aromatic ring-containing monomer (C-2) is preferably a monomer having R ₆ as hydrogen or a methyl group, and from the viewpoint of water resistance, styrene, vinyl naphthalene, α-methylstyrene, vinyl toluene, ethyl vinyl benzene, and One or more selected from 4-vinylbiphenyl is preferred. Among these, at least one selected from styrene, α-methylstyrene, vinyl toluene, and vinyl naphthalene is more preferable from the viewpoint of printing density and scratch resistance.

Examples of the macromer (C-3) include a macromer having a polymerizable functional group at one terminal and having a number average molecular weight of 400 to 500,000, more preferably 600 to 12,000.
Specific examples of the macromer include a styrenic macromer having a polymerizable functional group at one end, a silicone macromer having a polymerizable functional group at one end, a methyl methacrylate macromer having a polymerizable functional group at one end, Examples thereof include styrene / acrylonitrile macromers having a polymerizable functional group, butyl acrylate macromers having a polymerizable functional group at one end, and isobutyl methacrylate macromers having a polymerizable functional group at one end. In these, since formation of the water-insoluble vinyl polymer particle containing a coloring agent is easy, the styrenic macromer which has a polymerizable functional group in one terminal is preferable.

Examples of the styrenic macromer having a polymerizable functional group at one end include a styrene homopolymer having a polymerizable functional group at one end, and a copolymer of styrene and another monomer having a polymerizable functional group at one end. Is mentioned. Among the styrenic macromers having a polymerizable functional group at one end, a styrenic macromer having an acryloyloxy group or a methacryloyloxy group as a polymerizable functional group at one end is preferable from the viewpoint of dispersibility.
Examples of commercially available styrenic macromers include AS-6 (S), AN-6 (S), HS-6 (S) manufactured by Toa Gosei Co., Ltd., and the like.
The number average molecular weight of the macromer is measured using polystyrene as a standard substance by gel chromatography using 1 mmol / L dodecyldimethylamine-containing chloroform as a solvent.
The content of the monomer (C) in the monomer mixture used for polymerizing the water-insoluble vinyl polymer is preferably 50% by mass to 95% by mass, and 60% by mass to 85% by mass from the viewpoint of storage stability and water resistance. % Is more preferable.

When the aromatic ring-containing monomer (C-2) is used as the monomer (C), the content of the aromatic ring-containing monomer in the monomer (C) is the monomer mixture used for polymerizing the water-insoluble vinyl polymer. The content of the aromatic ring-containing monomer in is preferably 30% by mass to 80% by mass, and more preferably 35% by mass to 75% by mass from the viewpoint of scratch resistance and ink viscosity.
When the macromer of (C-3) is used as the monomer (C), the content of the macromer in the monomer (C) is preferably 3% by mass to 40% by mass from the viewpoint of water resistance and scratch resistance. 5 mass%-25 mass% are more preferable.

The weight average molecular weight of the water-insoluble vinyl polymer is preferably from 3,000 to 300,000, more preferably from 5,000 to 200,000, from the viewpoints of print density and ejection stability.
The weight average molecular weight of the water-insoluble vinyl polymer is isolated by drying a part of the obtained polymer solution at 105 ° C. under reduced pressure for 2 hours and removing the solvent. The weight average molecular weight can be measured by gel permeation chromatography using polystyrene as a standard substance and 60 mmol / L phosphoric acid and 50 mmol / L lithium bromide-containing dimethylformamide as a solvent.

The water-insoluble vinyl polymer is produced by polymerizing the monomers (A), (B), and (C) by a known polymerization method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method. The Among these polymerization methods, the solution polymerization method is preferable.
The solvent used in the solution polymerization method is preferably a polar organic solvent. When the polar organic solvent is miscible with water, it can be used by mixing with water. Examples of the polar organic solvent include aliphatic alcohols having 1 to 3 carbon atoms such as methanol, ethanol and propanol; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate and the like. Among these, methanol, ethanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, or a mixed solution of these with water is preferable. If necessary, toluene may be used.

In the polymerization, a radical polymerization initiator can be used. Examples of the radical polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2′-azobisbutyrate, 2, An azo compound such as 2′-azobis (2-methylbutyronitrile) or 1,1′-azobis (1-cyclohexanecarbonitrile) is preferable. Moreover, organic peroxides, such as t-butyl peroxy octoate, di-t-butyl peroxide, dibenzoyl oxide, can also be used.
The amount of the polymerization initiator is preferably 0.001 mol to 5 mol, more preferably 0.01 mol to 2 mol, per mol of the monomer mixture.

  In the polymerization, a polymerization chain transfer agent may be further added. Specific examples of the polymerization chain transfer agent include mercaptans such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan and 2-mercaptoethanol; xanthogen disulfides such as dimethylxanthogen disulfide and diisopropylxanthogen disulfide. Thiuram disulfides such as tetramethylthiuram disulfide and tetrabutylthiuram disulfide; Halogenated hydrocarbons such as carbon tetrachloride and ethylene bromide; Hydrocarbons such as pentaphenylethane; Acrolein, methacrolein, allyl alcohol, 2 -Ethylhexyl thioglycolate, terbinolene, α-terpinene, γ-terpinene, dipentene, α-methylstyrene dimer, 9,10-dihydroanthrace , 1,4-dihydronaphthalene, indene, 1,4-cyclohexadiene unsaturated cyclic hydrocarbon compounds of a diene and the like; 2,5-unsaturated heterocyclic compounds dihydrofuran like, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Since the polymerization conditions of the monomer differ depending on the radical polymerization initiator, the monomer, the type of the solvent, and the like, it cannot be determined unconditionally. Usually, the polymerization temperature is preferably 30 ° C to 100 ° C, more preferably 50 ° C to 85 ° C. The polymerization time is preferably 2 hours to 24 hours. The polymerization atmosphere is preferably an inert gas atmosphere such as nitrogen gas. After completion of the polymerization reaction, the produced water-insoluble vinyl polymer can be isolated from the reaction solution by a known method such as reprecipitation or solvent distillation. The obtained water-insoluble vinyl polymer can be purified by repeating reprecipitation or removing unreacted monomers by membrane separation, chromatographic methods, extraction methods, and the like.

<< Aqueous dispersion of pigment coated with water-insoluble vinyl polymer >>
As a method for obtaining an aqueous dispersion of a pigment coated with the water-insoluble vinyl polymer as the colorant, the water-insoluble vinyl polymer is dissolved in an organic solvent, and the pigment, water, neutralizing agent, and as necessary. A method of adding a surfactant and kneading, then diluting with water as necessary, and distilling off the organic solvent to form an aqueous system is preferred. The content of the pigment is preferably 20 parts by weight to 1,200 parts by weight, and 50 parts by weight with respect to 100 parts by weight of the water-insoluble vinyl polymer, from the viewpoint of printing density and ease of inclusion in the water-insoluble vinyl polymer particles. Part to 900 parts by weight is more preferable, and 65 parts to 600 parts by weight is even more preferable.

The organic solvent is preferably an alcohol solvent, a ketone solvent, or an ether solvent, and more preferably a hydrophilic organic solvent.
Examples of the alcohol solvent include isopropanol, n-butanol, tertiary butanol, isobutanol, diacetone alcohol, and the like.
Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone.
Examples of the ether solvent include dibutyl ether, tetrahydrofuran, dioxane and the like. Among these solvents, acetone, methyl ethyl ketone, and methyl isobutyl ketone are preferable, and toluene may be used in combination as necessary.

  A base is used as the neutralizing agent. Specific examples include tertiary amines such as trimethylamine and triethylamine, ammonia, sodium hydroxide, potassium hydroxide and the like. There is no restriction | limiting in particular in a neutralization degree, Usually, it is preferable that the liquid property of the obtained water dispersion is neutral, for example, pH is 4-10.

Depending on the type of the salt-forming group, the solubility of the water-insoluble vinyl polymer in water at 25 ° C. after neutralizing the salt-forming group with sodium hydroxide or acetic acid is 100%. In view of the above, it is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 1% by mass or less.
The average particle diameter of the water-insoluble vinyl polymer particles containing the colorant in the water dispersion and the water-based ink of the present embodiment is 0.01 μm to 0.50 μm from the viewpoint of prevention of nozzle clogging and storage stability. Preferably, 0.02 μm to 0.30 μm is more preferable, and 0.04 μm to 0.20 μm is still more preferable.

The surfactant in the third form functions as a dispersant.
There is no restriction | limiting in particular as surfactant (dispersant) used for carbon black, According to carbon black classification, it can select suitably, For example, anionic surfactant, nonionic surfactant, etc. are mentioned.
Examples of the anionic surfactant include alkyl sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, sodium naphthalene sulfonate formalin condensate, alkane or olefin sulfonate, alkyl sulfate, polyoxyethylene alkyl. Alternatively, surfactants selected from the group consisting of alkyl aryl ether sulfates, alkyl phosphates, alkyl diphenyl ether disulfonates, ether carboxylates, alkyl sulfosuccinates, α-sulfo fatty acid esters, and fatty acid salts, and higher fatty acids And condensates of amino acids and naphthenates.

Examples of the nonionic surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearin ether, polyoxyethylene oleyl ether, and polyoxyethylene alkyl ether. Polyoxyethylene alkyl phenyl ether such as ethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene α naphthyl ether, polyoxyethylene β naphthyl ether, polyoxyethylene monostyryl phenyl ether, polyoxyethylene distyryl phenyl ether, Polyoxyethylene alkyl naphthyl ether, polyoxyethylene monostyryl naphthyl ether, polyoxyethylene Examples thereof include tylene styryl naphthyl ether and polyoxyethylene polyoxypropylene block copolymers.
Among these, aromatic sulfonates such as sodium naphthalene sulfonate formalin condensate are preferable in terms of dispersibility with carbon black and foaming property of the surfactant.

The aromatic sulfonate is a product obtained by introducing sulfonic acid into an aromatic and neutralizing with a basic compound. Benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, alkylnaphthalenesulfonic acid or the like is butylamine, Alkylamines such as triethylamine, alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, morpholine, aqueous ammonia, sodium hydroxide, lithium hydroxide, potassium hydroxide, aminomethylpropanediol, aminoethylpropanediol And those neutralized with choline or the like. Moreover, you may use buffer agents, such as a tris hydroxylmethylaminomethane and a good buffer, as a basic compound. A substance obtained by condensing an aromatic sulfonate with formalin or the like can also be used.
The sodium naphthalene sulfonate formalin condensate is a condensate of sodium naphthalene sulfonate and formaldehyde, and is not particularly limited as long as it consists of repetition of the condensate.

  The surfactant (dispersant) used in the color pigment ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, a compound represented by the following general formula (4) is used. Thus, an aqueous pigment ink having a small average particle size and a small standard deviation in the particle size distribution can be obtained.

<General formula (4)>
In the general formula (4), n is preferably 20 or more and 100 or less, and more preferably 30 or more and 50 or less. When n is less than 20, the dispersion stability tends to decrease, and the ink has a large average particle size and a large standard deviation in the particle size distribution, so that satisfactory saturation may not be obtained. On the other hand, if n exceeds 100, the viscosity of the ink tends to increase, and printing by the inkjet method tends to be difficult.
The dispersant represented by the general formula (4) is preferably POE (n = 40) β-naphthyl ether.

  The content of the colorant in the inkjet recording ink is preferably 2% by mass to 15% by mass, more preferably 3% by mass to 10% by mass, and still more preferably 4% by mass to 8% by mass. When the content is less than 2% by mass, the color developability and the image density of the ink may be lowered. When the content exceeds 15% by mass, the ink is thickened and the ejection stability may be lowered. is there.

<Other ingredients>
Examples of the other components include other components such as a pH adjuster, an antiseptic / antifungal agent, a chelating reagent, a rust inhibitor, an antioxidant, an ultraviolet absorber, an oxygen absorber, and a light stabilizer. Become.

-PH adjuster-
The pH adjuster is not particularly limited as long as it can adjust the pH without adversely affecting the performance of the ink for inkjet recording, and can be appropriately selected according to the purpose. The ozone-oxidized carbon black dispersion liquid The same basic compounds can be used. Of these, aminopropanediol compounds are particularly preferred.

-Antiseptic and fungicide-
Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, sodium pentachlorophenol, and the like.

-Chelating reagent-
Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.

-Antirust agent-
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

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

  Examples of the phenolic antioxidant (including hindered phenolic antioxidant) include butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) ) Propionyloxy] ethyl] -2,4,8,10-tetrixaspiro [5,5] undecane, 1,1,3 Tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl ) Benzene, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, and the like.

  Examples of the amine-based antioxidant include phenyl-β-naphthylamine, α-naphthylamine, N, N′-di-sec-butyl-p-phenylenediamine, phenothiazine, N, N′-diphenyl-p-phenylenediamine. 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl-phenol, butylhydroxyanisole, 2,2′-methylenebis ( 4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), tetrakis [methylene -3 (3,5-di-tert-butyl-4-dihydroxyphenyl) propio Nate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, and the like.

  Examples of the sulfur-based antioxidant include dilauryl-3,3′-thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, dimyristyl-3,3′-thiodipropionate, di Examples include stearyl-β, β′-thiodipropionate, 2-mercaptobenzimidazole, dilauryl sulfide, and the like.

  Examples of the phosphorus antioxidant include triphenyl phosphite, octadecyl phosphite, triisodecyl phosphite, trilauryl trithiophosphite, and trinonylphenyl phosphite.

-UV absorber-
Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex ultraviolet absorber.

  Examples of the benzophenone-based ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. 2,2 ′, 4,4′-tetrahydroxybenzophenone, and the like.

  Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, and the like.

  Examples of the salicylate UV absorber include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, and the like.

  Examples of the cyanoacrylate ultraviolet absorber include ethyl-2-cyano-3,3′-diphenyl acrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate, and butyl-2- And cyano-3-methyl-3- (p-methoxyphenyl) acrylate.

  Examples of the nickel complex ultraviolet absorber include nickel bis (octylphenyl) sulfide, 2,2′-thiobis (4-tert-octylferrate) -n-butylamine nickel (II), 2,2′-thiobis. (4-tert-octylferrate) -2-ethylhexylamine nickel (II), 2,2′-thiobis (4-tert-octylferrate) triethanolamine nickel (II), and the like.

  The ink for inkjet recording of the present invention is not particularly limited and can be produced by a known method. For example, the colorant, the compound having a group represented by the structural formula (1), the water, the water-soluble The organic organic solvent and the compound represented by the general formula (1), if necessary, other ingredients, stirring and mixing using a sand mill, ball mill, roll mill, bead mill, nanomizer, homogenizer, ultrasonic disperser, etc. It is obtained by filtering coarse particles with a filter, a centrifugal separator or the like and degassing as necessary. 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.

  There is no restriction | limiting in particular as coloring of the ink for inkjet recording of this invention, According to the objective, it can select suitably, Yellow, magenta, cyan, black etc. are mentioned. When recording is performed using an ink set in which two or more of these colorings are used in combination, a multicolor image can be formed. When recording is performed using an ink set in which all colors are combined, a full color image is formed. be able to.

There is no restriction | limiting in particular as a physical property of the ink for inkjet recording of this invention, According to the objective, it can select suitably, For example, it is preferable that surface tension, pH, etc. are the following ranges.
The surface tension of the ink for ink jet recording is preferably 25 mN / m to 55 mN / m at 20 ° C. If the surface tension is less than 25 mN / m, bleeding on the recording medium becomes remarkable and stable jetting may not be obtained. If the surface tension exceeds 55 mN / m, ink penetration into the recording medium is sufficient. However, the drying time may be prolonged.
The pH of the inkjet recording ink is preferably 7 to 10, for example.

  The ink for ink jet recording of the present invention can be suitably used in various fields, and can be suitably used in an image recording apparatus (printer or the like) by an ink jet recording method. The ink for ink jet recording is heated at 50 ° C. to 200 ° C. and can be used for a printer or the like having a function of promoting print fixing. The ink cartridge, ink jet recording apparatus, and ink jet recording of the present invention described below It can be used particularly preferably in the method.

(ink cartridge)
The ink cartridge of the present invention contains the ink for ink jet recording of the present invention in a container, and further includes other members and the like 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 bag formed of an aluminum laminate film, a resin film, or the like Preferred examples include those possessed.

Next, the ink cartridge will be described with reference to FIGS. Here, FIG. 1 is a view showing an example of the ink cartridge of the present invention, and FIG. 2 is a view including a case (exterior) of the ink cartridge of FIG.
As shown in FIG. 1, the ink cartridge 200 is filled into the ink bag 241 from the ink inlet 242 and exhausted, and then the ink inlet 242 is closed by fusion. In use, the needle of the apparatus main body is pierced into the ink discharge port 243 made of a rubber member and supplied to the apparatus.
The ink bag 241 is formed of a packaging member such as a non-permeable aluminum laminate film. As shown in FIG. 2, the ink bag 241 is usually housed in a plastic cartridge case 244 and is detachably attached to various ink jet recording apparatuses.

  The ink cartridge of the present invention contains the ink for ink jet recording of the present invention, and can be used by being detachably attached to various ink jet recording apparatuses, but is detachably attached to the ink jet recording apparatus of the present invention described later. It is particularly preferable to use them.

(Inkjet recording apparatus and inkjet recording method)
The ink jet recording apparatus of the present invention includes at least ink flying means, and further includes other means appropriately selected as necessary, for example, stimulus generation means, reversing means, control means, and the like.
The ink jet recording method used in the present invention includes at least an ink flying process and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a reversal process, a control process, and the like.
The ink jet recording method used in the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.

<Ink flying process and ink flying means>
The ink flying step is a step of recording an image by applying a stimulus to the ink jet recording ink of the present invention and causing the ink jet recording ink to fly.
The ink flying means is means for recording an image by applying a stimulus to the ink jet recording ink of the present invention and causing the ink jet recording ink to fly. There is no restriction | limiting in particular as said ink flying means, For example, the recording head which has various nozzles for ink discharge etc. are mentioned.

In the present invention, it is preferable that at least a part of the liquid chamber portion, the fluid resistance portion, the vibration plate, and the nozzle member of the recording head is formed of a material containing at least one of silicon and nickel.
The nozzle diameter of the nozzle is preferably 30 μm or less, and preferably 1 μm to 20 μm.
The recording head preferably has a nozzle plate having a water repellent treatment applied to the ink ejection surface, and the water repellent finish is any one selected from PTFE-Ni eutectoid processing, fluororesin processing, and silicone resin processing. It is preferable that
It is preferable that the recording head has a sub tank for supplying ink for ink jet recording, and the sub tank is replenished with ink for ink jet recording from an ink cartridge through a supply tube.

  The size of the droplets of the ink jet recording ink to be ejected is preferably 3 pl to 40 pl, the ejection speed is preferably 5 m / s to 20 m / s, and the drive frequency is, for example, 1 kHz or more is preferable, and the resolution is preferably 300 dpi or more.

<Other processes and other means>
-Stimulus generation process and stimulus generation means-
The stimulus can be generated, for example, by the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, such as heat (temperature), pressure, vibration, light, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferable.

  Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a light, and the like. Specifically, for example, a piezoelectric actuator such as a piezoelectric element, a heating resistor, etc. Examples include a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a body, a shape memory alloy actuator that uses a metal phase change caused by a temperature change, and an electrostatic actuator that uses an electrostatic force.

  There is no particular limitation on the manner of flying the ink jet recording ink, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, recording is performed on the ink jet recording ink in the recording head. Thermal energy corresponding to the signal is applied using, for example, a thermal head, bubbles are generated in the inkjet recording ink by the thermal energy, and the inkjet recording ink is generated from the nozzle holes of the recording head by the pressure of the bubbles. And the like. Further, when the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. And a method of ejecting and ejecting the ink jet recording ink as droplets from the nozzle holes of the recording head.

-Control process and control means-
The control step is a step of controlling the movement of each step, and can be performed by the control means. There is no restriction | limiting in particular as said control means, According to the objective, it can select suitably, For example, a sequencer, a computer, etc. are mentioned.

One mode for carrying out the ink jet recording method used in the present invention by the ink jet recording apparatus of the present invention will be described with reference to the drawings.
The ink jet recording apparatus shown in FIG. 3 stocks an apparatus main body 101, a paper feed tray 102 for loading paper loaded on the apparatus main body 101, and paper on which an image is recorded (formed) mounted on the apparatus main body 101. A paper discharge tray 103 and an ink cartridge loading unit 104. On the upper surface of the ink cartridge loading unit 104, an operation unit 105 such as operation keys and a display is arranged. The ink cartridge loading unit 104 has a front cover 115 that can be opened and closed for attaching and detaching the ink cartridge 200. In FIG. 3, reference numeral 111 denotes an upper cover, and 112 denotes a front surface of the front cover.

In the apparatus main body 101, as shown in FIG. 4, a carriage 133 is slidably held in the main scanning direction by a guide rod 131 and a stay 132, which are guide members horizontally mounted on left and right side plates (not shown). Then, the scanning is moved by a main scanning motor (not shown).
The carriage 133 has a plurality of ink ejection openings of a recording head 134 including four inkjet recording heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.
As the ink jet recording head constituting the recording head 134, a piezoelectric actuator such as a piezoelectric element, a thermal actuator using phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a metal phase due to temperature change, etc. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging ink can be used.
In addition, the carriage 133 is equipped with a sub tank 135 for each color for supplying ink of each color to the recording head 134. The sub tank 135 is supplied with ink for ink jet recording of the present invention from the ink cartridge 200 of the present invention loaded in the ink cartridge loading section 104 via an ink supply tube (not shown).

On the other hand, as a paper feeding unit for feeding the paper 142 stacked on the paper stacking unit (pressure plate) 141 of the paper feed tray 102, the half-moon roller [feeding the paper 142 one by one from the paper stacking unit 141] The sheet roller 143] and the sheet feeding roller 143 are opposed to each other, and a separation pad 144 made of a material having a large friction coefficient is provided. The separation pad 144 is urged toward the sheet feeding roller 143 side.
As a transport unit for transporting the paper 142 fed from the paper feed unit below the recording head 134, a transport belt 151 for transporting the paper 142 by electrostatic adsorption and a guide 145 from the paper feed unit. The counter roller 152 for transporting the paper 142 fed via the transport belt 151 with the transport belt 151 and the paper 142 fed substantially vertically upward are changed by approximately 90 ° so as to follow the transport belt 151. A conveying guide 153 and a tip pressure roller 155 urged toward the conveying belt 151 by a pressing member 154, and a charging roller 156 as a charging means for charging the surface of the conveying belt 151. It has been.

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

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

When the ink remaining amount near end in the sub tank 135 is detected, a required amount of ink is supplied from the ink cartridge 200 to the sub tank 135.
In this ink jet recording apparatus, when the ink in the ink cartridge 200 is used up, the casing of the ink cartridge 200 can be disassembled and only the ink bag inside can be replaced. Further, the ink cartridge 200 can supply ink stably even when the ink cartridge 200 is installed vertically and has a front loading configuration. Accordingly, when the upper portion of the apparatus main body 101 is closed and installed, for example, even when the apparatus main body 101 is stored in a rack or an object is placed on the upper surface of the apparatus main body 101, the ink cartridge 200 is replaced. Can be easily performed.
Here, an example is described in which the present invention is applied to a serial (shuttle type) ink jet recording apparatus that is scanned by a carriage, but the present invention can be similarly applied to a line type ink jet recording apparatus having a line type head.

  The ink jet recording apparatus and the ink jet recording method of the present invention can be applied to various types of recording by the ink jet recording method, and are particularly suitable for, for example, an ink jet recording printer, a facsimile apparatus, a copying apparatus, and a printer / fax / copier multifunction machine. Can be applied to.

<Ink record>
The ink recorded matter used in the present invention has an image formed on the recording medium using the ink jet recording ink of the present invention.

-Recording media-
The recording medium is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the recording medium has an absorptivity with respect to ink jet recording ink such as paper, and substantially with respect to ink jet recording ink. Any of the non-absorbing materials are preferably used.
Examples of the recording medium include plastic sheets based on polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polysulfone, ABS resin, polyvinyl chloride, etc .; metals such as brass, iron, aluminum, stainless steel (SUS), and copper A recording medium in which a metal coating treatment is applied to a surface or non-metallic substrate by a technique such as vapor deposition; a recording medium that has been subjected to water repellency treatment using paper as a substrate; a so-called ceramic material obtained by firing an inorganic material at a high temperature Examples include recording media. Among these, paper is preferable from the viewpoint of economy and the naturalness of an image, and in the present invention, both smooth paper and non-smooth paper are preferably used.

Smooth paper and non-smooth paper as the recording medium can be classified into smooth paper and non-smooth paper by measuring the smoothness and using the smoothness.
The non-smooth paper is plain paper having a smoothness of less than 500 seconds and not subjected to a surface coating or the like.
Many of the smooth papers are surface-coated and have a smoothness of 500 seconds or more, and examples include glossy papers such as art papers and cast-coated papers.
The smoothness is, for example, an Oken type measuring instrument that places a hollow head on the paper surface, reduces the pressure inside, and measures the smoothness according to the time (seconds) that a certain amount of air flows from the gap between the head and the paper surface. Can be measured.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Production Examples 1-6)
-Polymer synthesis-
In a reaction vessel, 20 parts by mass of methyl ethyl ketone, 0.03 part by mass of a polymerization chain transfer agent (2-mercaptoethanol), and 10% by mass of each monomer (indicated by mass) shown in Table 1 are added and mixed. Then, nitrogen gas replacement was sufficiently performed to obtain a mixed solution.
On the other hand, the remaining 90% by mass of each monomer (indicated by mass) shown in Table 1 was charged into the dropping funnel, and then 0.27 parts by mass of a polymerization chain transfer agent (2-mercaptoethanol), methyl ethyl ketone 60 Part by mass and 1.2 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) were mixed and mixed, and nitrogen gas substitution was sufficiently performed to obtain a mixed solution.

Under a nitrogen atmosphere, the mixed solution in the reaction vessel was heated to 75 ° C. while stirring, and the mixed solution in the dropping funnel was gradually dropped into the reaction vessel over 3 hours. After completion of the dropwise addition, the liquid temperature of the mixed solution was maintained at 75 ° C. for 2 hours, and then a solution in which 0.3 part by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in 5 parts by mass of methyl ethyl ketone was prepared. In addition to the mixed solution, the mixture was further aged at 75 ° C. for 2 hours and 85 ° C. for 2 hours to obtain each polymer solution.
A portion of each polymer solution obtained was isolated by drying at 105 ° C. under reduced pressure for 2 hours and removing the solvent. The weight average molecular weight was measured by gel permeation chromatography using polystyrene as a standard substance and 60 mmol / L phosphoric acid and 50 mmol / L lithium bromide-containing dimethylformamide as a solvent. The results are shown in Table 1.

  The details of each compound shown in Table 1 are as follows.

[General formula (VI)]
In the general formula (VI), R ₁ represents a hydrogen atom or a methyl group. R ₂ represents an alkylene group having 2 to 8 carbon atoms or an alkylene group having 2 to 4 carbon atoms in which a hydrogen atom is substituted with a phenyl group. However, a C2-C4 ethylene group, a propylene group, and a butylene group are preferable. n is an average added mole number, and is a number of 2-30. R ₃ represents a linear or branched alkyl group having 2 to 30 carbon atoms.

* Ethoxypolyethylene glycol monomethacrylate: a compound in which n is 9, R ₁ is a methyl group, R ₂ is an ethylene group, and R ₃ is an ethyl group in the general formula (VI) * Octoxypolyethylene glycol monomethacrylate: the general formula In (VI), n is 6, R ₁ is a methyl group, R ₂ is an ethylene group, and R ₃ is an octyl group. * Octoxypolyethylene glycol / polypropylene glycol monomethacrylate: In the general formula (VI), n is 6 (average added mole number of polyethylene glycol is 4, average added mole number of polypropylene glycol is 2), R ₁ is methyl group, R ₂ is ethylene group and propylene group, R ₃ is octyl group, Compound with random addition of oxyethylenepropylene group * Lauroki Sipolyethylene glycol monomethacrylate: a compound in which n is 4, R ₁ is a methyl group, R ₂ is an ethylene group, and R ₃ is a dodecyl group in the general formula (IV). IV), a compound in which n is 9, R ₁ is a methyl group, R ₂ is an ethylene group, and R ₃ is an octadecyl group. * Polyethylene glycol monomethacrylate: In the general formula (IV), n is 15 and R ₁ is methyl. Group, R ₂ is an ethylene group and R ₃ is a hydrogen atom * Methacrylic acid: manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: GE-110 (MAA)
* 2-ethylhexyl methacrylate: manufactured by Mitsubishi Rayon Co., Ltd., trade name: acrylate EH
* Styrene monomer: Nippon Steel Chemical Co., Ltd., trade name: Styrene monomer * Styrene macromer: Toa Gosei Co., Ltd., trade name: AS-6S (styrene macromer), number average molecular weight 6,000

(Preparation Examples 1 to 7)
As shown in Table 2, the polymer obtained in Production Examples 1 to 6 was mixed with 77 parts by mass of methyl ethyl ketone adjusted to 50% by mass, 90 parts by mass of methyl ethyl ketone, and a neutralizing agent (5N aqueous sodium hydroxide solution). After neutralizing methacrylic acid by adding a predetermined amount (neutralization degree 90%), 370 parts by mass of ion-exchanged water, and further, 90 parts by mass of the pigment described in Table 2 below as a colorant were added and dispersed. Further, 20 passes were processed with a disperser (Microfluidizer M-140K, 150 MPa). In the case of using carbon black (Nipex 150, manufactured by Degussa), the pass processing of the disperser was made 5 passes.
After adding 100 parts by mass of ion-exchanged water to the obtained aqueous dispersion and stirring, methyl ethyl ketone was removed at 60 ° C. under reduced pressure, and a part of the water was further removed, followed by a filter with an average pore size of 5 μm [acetylcellulose Filtration with a 25 mL needleless syringe (made by Terumo Corporation) with a membrane, outer diameter: 2.5 cm, made by Fuji Film Co., Ltd., to remove coarse particles, and pigment aqueous dispersions of Preparation Examples 1 to 7 (All were 15 mass% as solid content).

(Preparation Examples 8 to 9)
-Formulation of black pigment dispersion-
-Pigment (carbon black, Nippon 150, manufactured by Degussa) ... 150 parts by mass-Surfactant species: I (see Table 3 below) ... 10 parts by mass-High purity water-remaining amount

-Color pigment dispersion formulation-
Pigment (Pigment Yellow 74, manufactured by Dainichi Seika Kogyo Co., Ltd.) 150 parts by mass Surfactant type: II (see Table 3 below) 60 parts by mass High purity water: remaining amount

<General formula (4)>

  The formulations of Preparation Examples 8 and 9 were premixed to obtain a mixed slurry. Using a disk type media mill (manufactured by Kotobuki Industries Co., Ltd., UAM type), using a zirconia bead with a diameter of 0.015 mm and a filling rate of 70%, a peripheral speed of 6 m / s and a liquid temperature of 10 ° C. to a specific average particle size After circulating and dispersing, after centrifuging coarse particles with a centrifugal separator (Model 7700, manufactured by Kubota Corporation), the mixture is filtered using a filter having a diameter of 1.2 μm to remove the coarse particles. The pigment aqueous dispersions of Examples 8 and 9 were obtained (both 15% by mass as the solid content).

(Examples 1-18 and Comparative Examples 1-5)
−Preparation of ink for ink jet recording−
Each inkjet recording ink was manufactured according to the following procedure.
First, a water-soluble organic solvent, a penetrating agent, a surfactant, a fungicide, a pH adjuster, and water shown in Tables 4 and 5 were mixed, and stirred for 1 hour and mixed uniformly. The pigment dispersion shown in Tables 4 and 5 and the foam inhibitor were added to this mixed solution and stirred for 1 hour. The dispersion was subjected to pressure filtration with a polyvinylidene fluoride membrane filter having an average pore size of 5.0 μm to remove coarse particles and dust, and the inks for inkjet recording of Examples 1 to 18 and Comparative Examples 1 to 5 were used. Produced.

In addition, the symbol in Table 4 and Table 5 represents the following meaning.
* Self-dispersed pigment dispersion 1: Cabot, CaboJet # 300, solid content 15% by mass * Self-dispersing pigment dispersion 2: Cabot, CaboJet # 260m, solid content 15% by mass
* ANTIFORM 1266: Silicone-based antifoaming agent (manufactured by Toray Dow Corning Co., Ltd., 100 mass% component)
* BYK-1615: Silicone-based antifoaming agent (by Big Chemie Japan Co., Ltd., component 100% by mass)
* KM-72F: Self-emulsifying silicone defoaming agent (manufactured by Shin-Etsu Silicone Co., Ltd., 100% by mass)
* Fluorosurfactant: Compound represented by the following general formula (2) (n = 10, 20, 40, or 50)
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· formula (2)
However, in said general formula (2), n is a natural number of 1-40.
* Fluorosurfactant: Compound represented by the following general formula (3) (n = 40) (Zonyl FS-300, manufactured by DuPont, 40 mass% component)
_{C 8 F 17 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· formula (3)
However, in said general formula (3), n represents the natural number of 1-40.
* Orphine EXP4001: acetylene glycol surfactant, manufactured by Nissin Chemical Industry Co., Ltd., 80% by mass of active ingredient
* Softanol EP-7025: polyoxyalkylene alkyl ether (manufactured by Nippon Shokubai Co., Ltd., component 100% by mass)
* Proxel GXL: Antifungal agent based on 1,2-benzisothiazolin-3-one (Avicia, 20% by mass, containing dipropylene glycol)

  Next, various characteristics of each ink-jet recording ink produced were evaluated as follows. The results are shown in Table 6.

<Evaluation of color development: saturation>
Using an ink jet printer (IPSIO GXe3300, manufactured by Ricoh Co., Ltd.), printing was performed on My Paper (manufactured by Ricoh Co., Ltd.), and printing patterns were printed with 100% duty for each ink jet recording ink of yellow, magenta and cyan . The printing conditions were 360 dpi and one-pass printing.
After printing and drying, each of the solid image portions of yellow, magenta, and cyan is measured with a reflective color spectrophotometric densitometer (manufactured by X-Rite), and the color difference display method L ^* a ^* b defined by CIE is used. ^* The coordinates of the color system were determined, and the saturation C ^* for each color was determined. The higher the saturation, the better the color. The saturation C ^* is defined by the following formula.
C ^* = [(a ^* ) ² + (b ^* ) ² ] ^1/2

<Beading evaluation>
Using an ink jet printer (IPSIO GXe3300, manufactured by Ricoh Co., Ltd.), printing is performed on the Ricoh Business Coat Gloss 100 (manufactured by Ricoh Co., Ltd.), and the printing patterns are black, yellow, magenta, and cyan ink jet recording inks. Printing was performed at 100% duty.
After the print was dried, the beading rank was visually confirmed for each color, and the beading was evaluated according to the following criteria.
〔Evaluation criteria〕
AA: There is no unevenness on the printed surface and the solid part is uniform. A: There is some unevenness but it is not so noticeable. B: Fine unevenness in the solid part can be confirmed. C: Large unevenness is observed in the solid part.

<Image density>
Using an inkjet printer (IPSIO GXe3300, manufactured by Ricoh Co., Ltd.), printing is performed on My Paper (manufactured by Ricoh Co., Ltd.). Was printed. The printing conditions were 360 dpi and one-pass printing.
After the print was dried, each solid image portion of black, yellow, magenta, and cyan was measured with a reflective color spectrophotometric densitometer (manufactured by X-Rite), and judged according to the following criteria.
〔Evaluation criteria〕
◎: Black ... 1.25 or more Yellow ... 0.85 or more Magenta ... 1.05 or more, or Cyan ... 1.05 or more ○: Black ... 1.2 or more 1.25 Less than Yellow ... 0.8 or more and less than 0.85 Magenta ... 1.0 or more and less than 1.05, or Cyan ···· 1.0 or more and less than 1.05 Δ: Black ··· 1.15 or more Less than 1.2 Yellow ... 0.75 to less than 0.8 Magenta ... 0.95 to less than 1.0, or Cyan ... 0.95 to less than 1.0 x: Black ... 1. Less than 15 Yellow ... less than 0.75 Magenta ... less than 0.95, or Cyan ... less than 0.95

<Defoaming property>
In an environment of 25 ° C., 10 mL of each ink-jet recording ink thus prepared is put into a 100 mL graduated cylinder, air of constant pressure is injected until the volume of each ink-jet recording ink and bubbles reaches 100 mL, and all bubbles are generated from there. The time until disappearance was defined as the defoaming time, and evaluation was performed according to the following criteria.
〔Evaluation criteria〕
A: Defoaming time less than 150 seconds B: Foaming time 150 seconds or more and less than 300 seconds C: Foaming time 300 seconds or more and less than 600 seconds D: Foaming time 600 seconds or more

<Evaluation of storage stability>
Using a viscometer (RE-550L, manufactured by Toki Sangyo Co., Ltd., cone 1 ° 3 ′ × R24), stored in a sealed container at 70 ° C. for 14 days in a sealed container (25 ° C.). From the viscosity after storage measured at 25 ° C., the storage stability was determined according to the following formula and evaluated based on the following criteria.
Storage stability (%) = (viscosity after storage / viscosity before storage) × 100
〔Evaluation criteria〕
○: Storage stability is within 100% ± 5% △: Storage stability is over 100% ± 5% to less than 100% ± 10% ×: Storage stability is over 100% ± 10%

From the results in Table 6, it was found that Examples 1 to 18 had higher saturation than Comparative Examples 1 to 5, and an intended image density was obtained.

As an aspect of this invention, it is as follows, for example.
<1> Inkjet recording comprising water, a water-soluble organic solvent, a colorant, a compound having a group represented by the following structural formula (1), and a compound represented by the following general formula (1) Ink.
_{C 6 F 13 -CH 2 CH 2} - ··· structural formula (1)
_{HO-R 1 R 3 C- [} CH 2] n -CR 2 R 4 -OH ··· formula (1)
In the general formula (1), _{R 1} and _{R 2} each independently represent an alkyl group having 3 to 6 carbon atoms, _{R 3} and _{R 4} are each independently an alkyl group having 1 to 2 carbon atoms N is an integer of 1-6.
<2> The ink for inkjet recording according to <1>, wherein the compound having a group represented by the structural formula (1) is a compound represented by the following general formula (2).
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· formula (2)
However, in said general formula (2), n is a natural number of 1-40.
<3> The compound represented by the general formula (1) is 2,4,7,9-tetramethyldecane-4,7-diol and 2,5,8,11-tetramethyldodecane-5,8-diol. The inkjet recording ink according to any one of <1> to <2>.
<4> The ink for inkjet recording according to any one of <1> to <3>, wherein the content of the compound represented by the general formula (1) is 0.05% by mass to 1.0% by mass. is there.
<5> The inkjet recording ink according to any one of <2> to <4>, wherein the content of the compound represented by the general formula (2) is 0.05% by mass to 5.0% by mass. is there.
<6> From the above <1> to <1>, wherein the colorant is a pigment, and the pigment is at least one selected from a self-dispersible pigment, a pigment dispersed with a surfactant, and a pigment coated with a polymer 5> The ink for inkjet recording according to any one of 5>.
<7> The inkjet recording ink according to any one of <1> to <6>, wherein the ink is at least one selected from cyan ink, magenta ink, yellow ink, and black ink.
<8> An ink cartridge characterized in that the ink for ink jet recording according to any one of <1> to <7> is contained in a container.
<9> At least an ink flying step of recording an image by applying a stimulus to the ink for ink jet recording according to any one of <1> to <7> and causing the recording ink to fly. Inkjet recording method.
<10> At least ink jetting means for recording an image by applying a stimulus to the ink for inkjet recording according to any one of <1> to <7> and causing the recording ink to fly. Inkjet recording apparatus.
<11> An ink recorded matter comprising an image recorded using the inkjet ink according to any one of <1> to <7> on a recording medium.

134 Recording head 200 Ink cartridge

JP 2010-275377 A

Claims (8)

An ink for inkjet recording, comprising water, a water-soluble organic solvent, a colorant, a compound represented by the following general formula (2) , and a compound represented by the following general formula (1).
_{HO-R 1 R 3 C- [} CH 2] n -CR 2 R 4 -OH ··· formula (1)
In the general formula (1), _{R 1} and _{R 2} each independently represent an alkyl group having 3 to 6 carbon atoms, _{R 3} and _{R 4} are each independently an alkyl group having 1 to 2 carbon atoms N is an integer of 1-6.
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· formula (2)
However, in said general formula (2), n is a natural number of 1-40. The compound represented by the general formula (1) is any of 2,4,7,9-tetramethyldecane-4,7-diol and 2,5,8,11-tetramethyldodecane-5,8-diol. The ink for ink jet recording according to claim 1. The inkjet recording ink according to claim 1, wherein the content of the compound represented by the general formula (1) is 0.05% by mass to 1.0% by mass. The ink for inkjet recording according to any one of claims 1 to 3, wherein the content of the compound represented by the general formula (2) is 0.05% by mass to 5.0% by mass. The colorant is a pigment, and the pigment is at least one selected from a self-dispersible pigment, a pigment dispersed with a surfactant, and a pigment coated with a polymer. The ink for inkjet recording as described. The ink for inkjet recording according to any one of claims 1 to 5, wherein the ink is at least one selected from cyan ink, magenta ink, yellow ink, and black ink. An ink cartridge, wherein the ink for ink jet recording according to claim 1 is contained in a container. An ink jet recording method comprising at least an ink flying step of recording an image by applying a stimulus to the ink for ink jet recording according to claim 1 and causing the recording ink to fly.