Ink and Inkjet Recording Apparatus

Abstract

To provide an ink that is excellent in dischargeability during ink filling, defoamability of ink, discharge stability, and ink passability.SOLUTION: An ink is used in an inkjet recording device having a filter for an ink channel, the ink containing water, a colorant, a silicone surfactant, and silicone compound particles. The silicone compound particles have a volume average size (D50) of 1.01 μm-5.00 μm. The content of the silicone compound particles is 0.01 mass%-0.20 mass%.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to ink and an inkjet recording apparatus.

Background Art

[0002] The inkjet recording method has the advantage that full-colorization is easy because the process is simple compared to other recording methods, and a high-resolution image can be obtained even with a device having a simple configuration. As ink for inkjet, dye-based ink in which various water-soluble dyes are dissolved in water or a mixture of water and a water-soluble humectant is used.

[0003] In recent years, due to the strengthening of environmental regulations, the regulation of fluorine-based surfactants has become stricter. Fluorine-based surfactants are often restricted in use. Since fluorine-based surfactants have very excellent properties such as wettability to a substrate and good defoaming properties, there is a problem that it is difficult to select alternative materials. Considering the environment, hydrocarbon-based surfactants have a lower environmental impact than fluorine-based or silicone-based surfactants. Therefore, it has been proposed to use a surfactant having an acetylene structure as a hydrocarbon-based surfactant to improve wettability and foaming properties (see Patent Document 1). However, even when a surfactant having an acetylene structure is used, the defoaming property is not sufficiently satisfactory.

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide an ink excellent in dischargeability during ink filling, defoaming property of the ink, discharge stability, and ink flowability.

Means for Solving the Problems

[0005] The ink of the present invention as a means for solving the above problems is an ink used in an inkjet recording apparatus having a filter in an ink flow path, and contains water, a coloring material, a silicone surfactant, and silicone compound particles, wherein the volume average particle diameter (D 50 ) of the silicone compound particles is 1.01 μm to 5.00 μm, and the content of the silicone compound particles is 0.01% by mass to 0.20% by mass.

Advantages of the Invention

[0006] According to the present invention, it is possible to provide an ink excellent in dischargeability during ink filling, defoaming property of the ink, discharge stability, and ink flowability.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0008] (Ink) The ink of the present invention is an ink used in an inkjet recording apparatus having a filter in an ink flow path, and contains water, a coloring material, a silicone surfactant, and silicone compound particles, wherein the volume average particle diameter (D 50 ) of the silicone compound particles is 1.01 μm to 5.00 μm, and the content of the silicone compound particles is 0.01% by mass to 0.20% by mass.

[0009] Conventionally, when using an ink container having an air introduction flow path for introducing air and having a structure for generating bubbles in the ink, bubbles flow out of the ink tank together with the ink and are carried to the ink ejection head, causing problems such as poor filling and ejection at the ink ejection head. Further, in an inkjet recording apparatus provided with an ink container in which air and ink can come into contact, such as an open-type ink cartridge, when ink is supplied to the ink ejection head, there has been a problem that ink containing bubbles is carried to the ink ejection head, resulting in poor filling and ejection at the ink ejection head. Such poor filling and ejection at the ink ejection head have led to deterioration of initial filling properties and continuous printing stability. In response to the above problems, the present inventor has conducted intensive studies and found that even when the ink having the above configuration does not contain a fluorine-based surfactant, it has excellent defoaming properties for the ink, and also has excellent ejection properties, ejection stability, and ink flowability during ink filling.

[0010] The ink contains water, a colorant, a silicone surfactant, and silicone compound particles, and further contains, if necessary, other components such as an organic solvent, resin particles, a surfactant other than the silicone surfactant, and various additives.

[0011] <Silicone surfactant> The silicone surfactant is not particularly limited and can be appropriately selected according to the purpose. For example, side-chain modified polydimethylsiloxane, both-terminal modified polydimethylsiloxane, one-terminal modified polydimethylsiloxane, side-chain and both-terminal modified polydimethylsiloxane, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, as the silicone surfactant, a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group is particularly preferable because it exhibits good properties as an aqueous surfactant.

[0012] As such silicone surfactants, those synthesized as appropriate may be used, or commercially available products may be used. Examples of commercially available products of the silicone surfactant include those available from Big Chem Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.

[0013] The polyether-modified silicone surfactant is not particularly limited and can be appropriately selected according to the purpose. For example, those in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylpolysiloxane represented by the following general formula (S-1) can be mentioned.

Chemical formula

[0014] As the polyether-modified silicone surfactant, commercially available products can be used. For example, KF-618, KF-642, KF-643 (all manufactured by Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-1906EX (all manufactured by Nippon Emulsion Co., Ltd.), DOWSIL FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (all manufactured by Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (all manufactured by Big Chem Co., Ltd.), TSF4440, TSF4452, TSF4453 (all manufactured by Toshiba Silicone Co., Ltd.), and the like.

[0015] Among these, as the silicone surfactant, the surfactant represented by the following general formula (1) is particularly preferable in terms of improving the ink flowability and the defoaming property of the ink.

Chemical formula

[0016] There is no particular limitation on the content of the silicone surfactant in the ink, and it can be appropriately selected according to the purpose.

[0017] The silicone surfactant in the ink can be confirmed by various analytical methods such as mass spectrometry, ultraviolet spectroscopy, infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, carbon-13 nuclear magnetic resonance spectroscopy, and elemental analysis.

[0018] <Silicone compound particles> The silicone compound particles are not particularly limited as long as they are silicone compound particles with a volume average particle diameter (D 50 ) of 1.01 μm to 5.00 μm, and can be appropriately selected according to the purpose. For example, polydimethylsiloxane particles can be used.

[0019] The volume average particle diameter (D 50 ) of the silicone compound particles is 1.01 μm to 5.00 μm, preferably 1.10 μm to 4.50 μm. When the volume average particle diameter (D 50 ) of the silicone compound particles is less than 1.01 μm, the initial filling property is poor and foaming of the ink occurs. When it exceeds 5.00 μm, the ejection stability and liquid flowability deteriorate. On the other hand, when the volume average particle diameter (D 50 ) of the silicone compound particles is 1.01 μm to 5.00 μm, it is advantageous in terms of improving the initial filling property, ejection stability, liquid flowability, and defoaming property.

[0020] The silicone compound particles may be directly blended in the ink, or may be blended as a silicone emulsion in which the silicone compound particles are dispersed in a liquid.

[0021] The silicone emulsion can be prepared by emulsifying about two silicone compound particles in the molecule using an anionic surfactant and water, and adding colloidal silica and an organotin compound as needed. The pH of the silicone emulsion is not particularly limited and can be appropriately selected according to the purpose, but 9 to 11.5 is preferred.

[0022] The content of the silicone compound particles in the ink is 0.01% by mass to 0.20% by mass based on the total amount of the ink. When the content of the silicone compound particles is 0.01% by mass to 0.20% by mass, it is advantageous in terms of improving ejection stability and liquid flowability.

[0023] The silicone compound particles in the ink can be confirmed by various analytical methods such as mass spectrometry, ultraviolet spectroscopy, infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, carbon-13 nuclear magnetic resonance spectroscopy, and elemental analysis.

[0024] <Colorant> The colorant is not particularly limited and can be appropriately selected according to the purpose, and examples include pigments, dyes, and the like.

[0025] The pigment is not particularly limited and can be appropriately selected according to the purpose, and examples include inorganic pigments, organic pigments, and the like. These can be used alone or in combination of two or more. Also, mixed crystals can be used.

[0026] Examples of the pigment include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, metallic pigments such as gold and silver, and metallic pigments.

[0027] Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, etc. In addition to these, carbon black produced by known methods such as the contact method, furnace method, and thermal method can also be used as the inorganic pigment.

[0028] Examples of the organic pigment include azo pigments, polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (for example, basic dye type chelates, acid dye type chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc.

[0029] Among these pigments, those having good affinity with the solvent are preferably used as the pigment. In addition, the use of resin hollow particles and inorganic hollow particles is also possible.

[0030] Specific examples of the pigment include, for black, carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper, iron (C.I. Pigment Black 11), and titanium oxide; and organic pigments such as aniline black (C.I. Pigment Black 1).

[0031] Furthermore, as specific examples of the pigment, for color use, C.I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213; C.I. Pigment Orange 5, 13, 16, 17, 36, 43, 51; C.I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88, 101 (Vermilion), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264; C.I. Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38; C.I. Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3, 15:4 (Phthalocyanine Blue), 16, 17:1, 56, 60, 63; C.I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36 and the like can be mentioned.

[0032] There are no particular restrictions on the dye, and it can be appropriately selected according to the purpose. For example, acid dyes, direct dyes, reactive dyes, basic dyes, etc. can be mentioned. These may be used alone or in combination of two or more.

[0033] Specific examples of the dyes include C.I. Acid Yellow 17, 23, 42, 44, 79, 142; C.I. Acid Red 52, 80, 82, 249, 254, 289; C.I. Acid Blue 9, 45, 249; C.I. Acid Black 1, 2, 24, 94; C.I. Food Black 1, 2; C.I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173; C.I. Direct Red 1, 4, 9, 80, 81, 225, 227; C.I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202; C.I. Direct Black 19, 38, 51, 71, 154, 168, 171, 195; C.I. Reactive Red 14, 32, 55, 79, 249; C.I. Reactive Black 3, 4, 35, and the like.

[0034] The content of the colorant is not particularly limited and can be appropriately selected according to the purpose. However, with respect to the total amount of the ink, 2% to 15% by mass is preferable, 3% to 12% by mass is more preferable, and 4% to 10% by mass is even more preferable.

[0035] In order to obtain the ink by dispersing the pigment, methods such as introducing a hydrophilic functional group into the pigment to form a self-dispersible pigment, coating the surface of the pigment with a resin for dispersion, and using a dispersant for dispersion can be mentioned.

[0036] As a method of introducing a hydrophilic functional group into the pigment to form a self-dispersible pigment, for example, a method of making it dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to the pigment (for example, carbon, etc.) can be mentioned.

[0037] As a method for coating and dispersing the surface of the pigment with a resin, for example, a method of including the pigment in microcapsules to make it dispersible in water can be mentioned. This can be paraphrased as resin-coated pigment. In this case, not all the pigments incorporated in the ink need to be coated with resin, and uncoated pigments or partially coated pigments may be dispersed in the ink as long as the effects of the present invention are not impaired.

[0038] As a method for dispersing using the dispersant, for example, methods of dispersing using known low-molecular dispersants and high-molecular dispersants typified by surfactants can be mentioned. There is no particular limitation on the dispersant, and it can be appropriately selected according to the type of the pigment and the like. For example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. can be mentioned. These may be used alone or in combination of two or more. Also, RT-100 (nonionic surfactant, manufactured by Takemoto Yushi Co., Ltd.) and sodium naphthalene sulfonate formalin condensate can also be preferably used as the dispersant.

[0039] The volume average particle diameter (D 50 ) of the pigment is not particularly limited and can be appropriately selected according to the purpose, but is preferably 20 nm to 200 nm, more preferably 30 nm to 150 nm, and still more preferably 50 nm to 120 nm. The volume average particle diameter of the pigment in the present invention is measured using a particle size distribution measuring device (NanoTrack UPA-EX150, manufactured by Nikkiso Co., Ltd.), and a sample diluted with pure water so that the solid content concentration of the pigment in the measurement sample is 0.01% by mass is used. With a particle refractive index of 1.51 and a particle density of 1.4 g / cm 3 , using the parameters of pure water as the solvent parameter, it is the 50% volume average particle diameter (D 50 ) measured at 23°C. In addition, when pigment-containing polymer particles are used as the colorant, the volume average particle diameter (D 50 ) as the pigment-containing polymer particles including the polymer part may be measured.

[0040] <<Ratio of [volume average particle diameter (D 50 ) of colorant / volume average particle diameter (D 50 ) of silicone compound particles]>> The volume average particle diameter (D 50 ) of the colorant and the volume average particle diameter (D 50 ) of the silicone compound particles, the ratio [volume average particle diameter (D 50 ) of colorant / volume average particle diameter (D 50 ) of silicone compound particles] is not particularly limited and can be appropriately selected according to the purpose. However, 0.02 to 0.1 is preferable, and 0.05 to 0.1 is more preferable. When the ratio [volume average particle diameter (D 50 ) of colorant / volume average particle diameter (D 50 ) of silicone compound particles] is within the range of 0.02 to 0.1, it is advantageous in terms of improving the liquid passing property of the ink.

[0041] <Water> The water is not particularly limited and can be appropriately selected according to the purpose. Examples include pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water. These can be used alone or in combination of two or more.

[0042] The content of the water is not particularly limited and can be appropriately selected according to the purpose. However, in terms of the drying property and ejection stability of the ink, 10% by mass or more and 90% by mass or less is preferable, and 20% by mass to 60% by mass is more preferable with respect to the total amount of the ink.

[0043] <Other components> The ink may further contain other components such as an organic solvent, resin particles, a surfactant other than the silicone surfactant, and various additives, if necessary.

[0044] <<Organic solvent>> The organic solvent is not particularly limited and can be appropriately selected according to the purpose. For example, water-soluble organic solvents, polyol compounds having 8 or more carbon atoms, glycol ether compounds, and the like can be mentioned. These may be used alone or in combination of two or more.

[0045] Examples of the water-soluble organic solvent include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, and the like. These may be used alone or in combination of two or more.

[0046] Specific examples of the water-soluble organic solvent include polyhydric alcohols such as ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 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-1,3-pentanediol, and petriol; polyhydric alcohol alkyl ethers 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; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone; amides such as formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide; amines such as monoethanolamine, diethanolamine, and triethylamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol; and propylene carbonate and ethylene carbonate.

[0047] Since the water-soluble organic solvent not only functions as a wetting agent but also provides good drying properties, it is preferable to use an organic solvent with a boiling point of 250°C or lower.

[0048] Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.

[0049] Specific examples of the glycol ether compound include polyhydric alcohol alkyl ethers 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, propylene glycol monoethyl ether; and polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, and the like.

[0050] 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.

[0051] The content of the organic solvent is not particularly limited and can be appropriately selected according to the purpose. However, in terms of excellent ejection stability, 30% to 50% by mass is preferable based on the total amount of the ink.

[0052] <Resin particles> The ink preferably contains resin particles mainly for the purpose of improving image rub resistance and storage stability when a pigment is used as a colorant. The resin particles are not particularly limited and can be appropriately selected according to the purpose. However, for improving the image rubbing resistance, resin particles of acrylic resin, styrene-acrylic resin, acrylic-silicon resin, and fluororesin are preferable. For improving the storage stability, resin particles of polyurethane resin, acrylic resin, and styrene-acrylic resin are preferable. However, since there are few resin particles that can achieve both improvement of image rubbing resistance and improvement of storage stability at the same time, two types of resin particles may be used in combination. These resin particles are commercially available in the form of a resin emulsion in which the resin particles are dispersed in water and are easily available. Therefore, the resin emulsion can be appropriately selected and used from commercially available products as needed. Next, as typical resin emulsions, urethane resin emulsion and acrylic resin emulsion will be exemplified.

[0053] (1) Urethane resin emulsion The urethane resin of the urethane resin emulsion is obtained by polymerizing a polyisocyanate and a polyether polyol, a polyester polyol, a polylactone polyol, a polycarbonate polyol, or the like.

[0054] Examples of the polyisocyanate include aliphatic diisocyanate compounds such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate; alicyclic diisocyanate compounds such as isophorone diisocyanate, hydrogenated xylylene diisocyanate, 1,4-cyclohexane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate; aromatic aliphatic diisocyanate compounds such as xylylene diisocyanate and tetramethylxylylene diisocyanate; aromatic diisocyanate compounds such as toluylene diisocyanate and phenylmethane diisocyanate; modified products of these diisocyanates (carbodiimide, uretdione, uretoimine-containing modified products, etc.).

[0055] Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like.

[0056] Examples of the polyester polyol include polyethylene adipate, polybutylene adipate, polyneopentyl adipate, poly-3-methylpentyl adipate, polyethylene / butylene adipate, polyneopentyl / hexyl adipate, and the like.

[0057] Examples of the polylactone polyol include polycaprolactone diol, polyol of polyomega-hydroxycaproic acid, and the like.

[0058] Examples of the polycarbonate polyol include known products such as products obtained from the reaction of a diol (e.g., 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, etc.), phosgene, and a diaryl carbonate (e.g., diphenyl carbonate, etc.) or a cyclic carbonate (e.g., ethylene carbonate, propylene carbonate, etc.).

[0059] (2) Acrylic resin emulsion The acrylic resin of the acrylic resin emulsion is obtained by polymerizing an acrylic monomer alone or copolymerizing it with other monomers.

[0060] Examples of the acrylic monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-pentyl acrylate, isopentyl acrylate, neopentyl acrylate, 3-(methyl)butyl acrylate, 2-ethylhexyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, phenyl acrylate, methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, 3-(methyl)butyl methacrylate, 2-ethylhexyl methacrylate, hexyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, and the like.

[0061] Examples of the other monomer include vinyl aromatic hydrocarbons such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, p-chlorostyrene, divinylbenzene; unsaturated carboxylic acids such as itaconic acid, maleic acid; N-substituted maleimide, maleic anhydride, vinyl ketone, vinyl acetate, vinylidene chloride, and the like.

[0062] These resin emulsions exhibit even better water dispersibility by introducing ionic groups into the resin. Examples of such ionic groups include sulfonic acid groups, carboxylic acid groups, sulfuric acid groups, phosphoric acid groups, phosphonic acid groups, and phosphinic acid groups, or their alkali metal bases, alkaline earth metal bases, ammonium bases, primary to tertiary amine groups, and the like. Among these, alkali metal carboxylate bases, ammonium carboxylate bases, alkali metal sulfonate bases, and ammonium sulfonate bases are preferred, and alkali metal sulfonate bases and ammonium sulfonate bases are particularly preferred in terms of water dispersion stability. The introduction of ionic groups into the resin is carried out by adding monomers having ionic groups during resin synthesis. Preferred as the salt are Li, K, or Na salts.

[0063] The volume average particle diameter (D 50 ) of the resin particles is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoints of obtaining good fixing properties and high image hardness, it is preferably 10 nm or more and 1,000 nm or less, more preferably 10 nm or more and 200 nm or less, and particularly preferably 10 nm or more and 100 nm or less. The volume average particle diameter (D 50 ) of the resin particles can be measured, for example, using a particle size distribution measuring device (NanoTrac UPA - EX150, manufactured by Nikkiso Co., Ltd.).

[0064] The content of the resin particles is not particularly limited and can be appropriately selected according to the purpose. However, with respect to the total amount of the ink, it is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less.

[0065] <<Surfactants other than silicone surfactants>> The ink contains the silicone surfactant, but surfactants other than the silicone surfactant can also be additionally contained. As the surfactant other than the silicone surfactant, there is no particular limitation, and it can be appropriately selected according to the type of the coloring agent and the combination of the organic solvents. However, those having low surface tension, high penetrability and leveling property without impairing the dispersion stability are preferable. These may be used alone or in combination of two or more. Among these, as the surfactant other than the silicone surfactant, at least one selected from an anionic surfactant having an acetylene structure and a nonionic surfactant having an acetylene structure, and at least one or more selected from surfactants to which a hydrocarbon-based ethylene oxide (EO) chain having no acetylene structure is added are more preferably mixed and used.

[0066] The content of the surfactant other than the silicone surfactant is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 0.01% by mass to 3.0% by mass, more preferably 0.1% by mass to 1% by mass, based on the total amount of the ink.

[0067] <<Additive>> The ink may contain additives such as an antifoaming agent, an antiseptic and antifungal agent, a rust preventive agent, and a pH adjuster as long as the effects of the present invention are not impaired.

[0068] - Antifoaming agent - There is no particular limitation on the antifoaming agent, and it can be appropriately selected according to the purpose. Examples thereof include polyether-based antifoaming agents and fatty acid ester-based antifoaming agents. These may be used alone or in combination of two or more.

[0069] - Antiseptic and antifungal agent - There is no particular limitation on the antiseptic and antifungal agent, and it can be appropriately selected according to the purpose. Examples thereof include 1,2-benzisothiazolin-3-one.

[0070] - Rust preventive agent - There is no particular limitation on the rust preventive agent, and it can be appropriately selected according to the purpose. Examples thereof include acidic sulfite and sodium thiosulfate.

[0071] -pH adjuster- There are no particular restrictions on the pH adjuster, and it can be appropriately selected according to the purpose. However, those capable of adjusting the pH to 7 or higher are preferred. Examples include amines such as diethanolamine and triethanolamine.

[0072] There are no particular restrictions on the content of the additive as long as the effects of the present invention are not impaired, and it can be appropriately selected according to the purpose.

[0073] There are no particular restrictions on the physical properties of the ink, and it can be appropriately selected according to the purpose. For example, it is preferable that the viscosity, surface tension, pH, etc. are within the following ranges.

[0074] There are no particular restrictions on the viscosity of the ink at 25°C, and it can be appropriately selected according to the purpose. However, 5 mPa·s to 15 mPa·s is preferred, and 5 mPa·s to 10 mPa·s is more preferred. By setting the ink viscosity to 5 mPa·s or higher, the effects of improving the printing density and character quality can be obtained. On the other hand, by suppressing the ink viscosity to 15 mPa·s or lower, the discharge stability can be ensured. Here, the viscosity of the ink can be measured at 25°C using, for example, a viscometer (RE-550L, manufactured by Toki Sangyo Co., Ltd.).

[0075] There are no particular restrictions on the surface tension of the ink, and it can be appropriately selected according to the purpose. However, at 25°C, 35 mN / m or less is preferred, and 32 mN / m or less is more preferred. When the surface tension is 35 mN / m or less, the leveling of the ink on the recording medium is improved.

[0076] There are no particular restrictions on the pH of the ink, and it can be appropriately selected according to the purpose. However, from the viewpoint of preventing corrosion of the metal members in contact with the liquid, 7 to 12 is preferred, and 8 to 11 is more preferred.

[0077] There are no particular restrictions on the coloring of the ink, and it can be appropriately selected according to the colorant. For example, yellow, magenta, cyan, black, etc. can be mentioned. When recording using an ink set in which two or more of these colorings are used in combination, a multicolor image can be formed. When recording using an ink set in which all colors are used in combination, a full-color image can be formed.

[0078] <Method for manufacturing ink> There are no particular restrictions on the method for manufacturing the ink, and it can be appropriately selected from known ink manufacturing methods. For example, water, a colorant, a silicone surfactant, and silicone compound particles with a volume average particle diameter (D 50 ) of 1.01 μm to 5.00 μm, and further, if necessary, other components such as an organic solvent, resin particles, a surfactant other than the silicone surfactant, and various additives are dispersed or dissolved in an aqueous medium, and further, if necessary, stirred and mixed to manufacture. Examples of such methods include this. The dispersion can be performed, for example, by a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc. The stirring and mixing can be performed by a stirrer equipped with a normal stirring blade, a magnetic stirrer, a high-speed disperser, etc.

[0079] The ink can be suitably used in an inkjet recording apparatus (such as a printer) having a filter in the ink flow path. For example, it can also be used in a printer having a function of promoting printing fixation by heating the recording medium and the ink at 50°C to 200°C before and after printing. Therefore, the ink can be particularly suitably used in the inkjet recording apparatus, inkjet recording method, ink cartridge, and ink recording product of the present invention described in detail below.

[0080] (Inkjet recording apparatus and inkjet recording method) The inkjet recording apparatus of the present invention has the ink of the present invention and a filter with an average pore diameter of 4 μm to 22 μm in the flow path of the ink, and further, if necessary, has other means such as ink flying means, stimulation generating means, control means, and treatment liquid applying means. Further, the inkjet recording method of the present invention includes an ink flying step of applying a stimulus to the ink of the present invention and flying the ink onto a recording medium to form an image, and further, if necessary, includes other steps such as a stimulation generating step, a control step, and a treatment liquid applying step. The inkjet recording method of the present invention can be preferably implemented by the inkjet recording apparatus of the present invention. Hereinafter, the inkjet recording method of the present invention will be described together with the description of the inkjet recording apparatus of the present invention.

[0081] <Filter> The inkjet recording apparatus includes at least one filter in the flow path of the ink. The average pore diameter of the filter is 4 μm to 22 μm, but from the viewpoints of discharge stability and liquid permeability, 5 μm to 20 μm is preferable. Further, the thickness of the filter is not particularly limited and can be appropriately selected from known ink manufacturing methods, but 0.1 mm to 0.5 mm is preferable.

[0082] The filter is not particularly limited as long as it is provided in the flow path of the ink, and may be provided in the ink supply path, but is preferably provided between the ink cartridge and the ink discharge head. The ink is excellent in defoaming property, but it is advantageous in that the defoaming property is further improved when the ink passes through the filter and is supplied to the ink discharge head.

[0083] The material of the filter is not particularly limited and can be appropriately selected according to the purpose. However, since it is constantly in contact with the ink, from the perspective of corrosion resistance, it is preferably made of stainless steel or polyimide. Among these, as the material of the filter, since it has excellent corrosion resistance, it is preferably austenitic stainless steel, and more preferably SUS304, SUS316, or SUS316L. The filter may be made of only one of these materials or may be made of two or more materials. Among these, it is preferable that the filter contains at least any one selected from SUS304, SUS316, and SUS316L, and more preferably consists of any one selected from SUS304, SUS316, and SUS316L.

[0084] The shape of the filter is not particularly limited as long as the average pore diameter of the filter is 4 μm to 22 μm, and it can be appropriately selected from known filters. Among these, when using a filter in which a large number of uniform holes are formed in a stainless steel or polyimide plate by punching, laser, etc., a sintered filter in which stainless steel fibers are laminated and sintered in a felt shape, or a twill woven filter formed by twill weaving stainless steel fibers, a more stable inkjet recording apparatus and ink supply unit with long-term ejection stability can be obtained, which is desirable.

[0085] <Ink ejection head> The ink ejection head of the inkjet recording apparatus is not particularly limited and can be appropriately selected from known ones. For example, a so-called piezo type (see Japanese Patent Application Laid-Open No. 2-51734) that deforms a diaphragm forming the wall surface of the ink flow path by using a piezoelectric element as pressure generating means for pressurizing the ink in the ink flow path, changes the volume in the ink flow path, and ejects ink droplets; a so-called thermal type (see Japanese Patent Application Laid-Open No. 61-59911) that generates bubbles by heating the ink in the ink flow path using a heating resistor; an electrostatic type (see Japanese Patent Application Laid-Open No. 6-71882) that disposes a diaphragm forming the wall surface of the ink flow path and an electrode opposite to each other, and deforms the diaphragm by the electrostatic force generated between the diaphragm and the electrode, thereby changing the volume in the ink flow path and ejecting ink droplets, etc. can be mentioned. The ink can be preferably used in any inkjet recording apparatus equipped with an ink ejection head.

[0086] <Recording medium> The recording medium used in the inkjet recording apparatus is not particularly limited and can be appropriately selected according to the purpose. For example, plain paper, glossy paper, special paper, cloth, film, OHP sheet, general-purpose printing paper, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, a coated paper based on photographic printing paper having a coating layer and excellent glossiness is preferably used. Also, when used for plain paper without a coating layer, plain paper with a sizing degree of 10S or more and an air permeability of 5S to 50S, which is generally used as copy paper, is preferable.

[0087] <Ink flight process and ink flight means> The ink flight process is a process of applying a stimulus (energy) to the ink, flying the ink, and forming an image on the recording medium. The ink flight means is means for applying a stimulus (energy) to the ink, flying the ink, and forming an image on the recording medium. The ink flight process is preferably performed by the ink flight means.

[0088] The ink flying means is not particularly limited, and examples thereof include various nozzles for ink ejection.

[0089] The nozzle diameter of the nozzle is not particularly limited and can be appropriately selected according to the purpose, but is preferably 30 μm or less, and more preferably 1 μm to 20 μm.

[0090] In the inkjet recording apparatus, at least a part of the liquid chamber portion, the fluid resistance portion, the diaphragm, and the nozzle member of the ink ejection head is preferably formed of a material containing at least one of silicon and nickel.

[0091] The mode of ink flight is not particularly limited and varies depending on the type of the stimulus and the like. For example, when the stimulus is "heat", thermal energy corresponding to a recording signal is applied to the ink in the ink ejection head using, for example, a thermal head, and bubbles are generated in the ink by the thermal energy, and the ink is ejected as droplets from the nozzle holes of the ink ejection head by the pressure of the bubbles. A method of ejecting and the like can be mentioned. Further, when the stimulus is "pressure", for example, by applying a voltage to a piezoelectric element adhered to a position called a pressure chamber in the ink flow path in the ink ejection head, the piezoelectric element bends, the volume of the pressure chamber decreases, and the ink is ejected as droplets from the nozzle holes of the ink ejection head. A method of ejecting and the like can be mentioned.

[0092] The size of the ink droplets to be flown, the ejection speed, the driving frequency, the resolution, etc. are not particularly limited and can be appropriately selected according to the purpose. However, the size of the ink droplets is 3×10 -15 m 3 ~40×10 -15 m 3 (3 pL to 40 pL) is preferable, the ejection speed is preferably 5 m / s to 20 m / s, the driving frequency is preferably 1 kHz or more, and the resolution is preferably 300 dpi or more.

[0093] <Stimulation Generation Step and Stimulation Generation Means> The stimulation generation step is a step of generating stimulation (energy) applied to the ink in the ink flight step. The stimulation generation means is means for generating stimulation (energy) applied to the ink by the ink flight means. The stimulation generation step is preferably performed by the stimulation generation means.

[0094] The stimulation (energy) is not particularly limited and can be appropriately selected according to the purpose. For example, heat (temperature), pressure, vibration, light, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, heat and pressure are preferable as the stimulation.

[0095] The stimulation generation means is not particularly limited and can be appropriately selected according to the purpose. For example, a heating device, a pressurizing device, a piezoelectric element, a vibration generation device, an ultrasonic oscillator, a light, etc. can be mentioned. Specific examples of the stimulation generation means include piezoelectric actuators such as piezoelectric elements, thermal actuators that utilize phase change by film boiling of a liquid using electrothermal conversion elements such as heating resistors, shape memory alloy actuators that utilize metal phase change due to temperature change, electrostatic actuators that use electrostatic force, etc.

[0096] <Control Step and Control Means> The control step is a step of controlling each step in the inkjet recording method. The control means is means for controlling each means in the inkjet recording apparatus. The control step is preferably performed by the control means.

[0097] The control means is not particularly limited as long as it can control the movement of each means, and can be appropriately selected according to the purpose. For example, devices such as a sequencer and a computer can be mentioned.

[0098] <Treatment Liquid Coating Step and Treatment Liquid Coating Means> The treatment liquid application step is a step of applying a treatment liquid to the recording medium either before or after or both before and after attaching the ink to the recording medium. The treatment liquid application means is means for applying a treatment liquid to the recording medium either before or after or both before and after attaching the ink to the recording medium. The treatment liquid application step is preferably performed by the treatment liquid application means. The treatment liquid application step and the treatment liquid application means can improve the image quality such as image density, bleeding, and blurring on the recording medium.

[0099] The treatment liquid (hereinafter sometimes referred to as "pretreatment liquid") applied to the recording medium before attaching the ink to the recording medium is not particularly limited and can be appropriately selected according to the purpose. For example, those containing a flocculant, an organic solvent, and water, and further containing a surfactant, an antifoaming agent, a pH adjuster, an antiseptic and antifungal agent, a rust preventive agent, etc. as required can be mentioned. These may be used alone or in combination of two or more. As the organic solvent, the surfactant, the antifoaming agent, the pH adjuster, the antiseptic and antifungal agent, and the rust preventive agent, the same materials as those used for the ink can be used, and in addition, materials used for known treatment liquids can also be used. The type of the flocculant is not particularly limited, and examples thereof include water-soluble cationic polymers, acids, polyvalent metal salts, etc.

[0100] The treatment liquid (hereinafter sometimes referred to as "post-treatment liquid") applied to the recording medium after attaching the ink to the recording medium is not particularly limited as long as it can form a transparent layer, and can be appropriately selected according to the purpose. For example, organic solvents, water, resins, surfactants, antifoaming agents, pH adjusters, antiseptic and antifungal agents, rust preventive agents, etc. can be mentioned. These may be used alone or in combination of two or more. As the organic solvent, the water, the resin, the surfactant, the antifoaming agent, the pH adjuster, the antiseptic and antifungal agent, and the rust preventive agent, the same materials as those used for the ink can be used, and in addition, materials used for known treatment liquids can also be used.

[0101] Here, one aspect of implementing the inkjet recording method of the present invention by a serial inkjet recording apparatus will be described with reference to the drawings. The inkjet recording apparatus shown in FIG. 1 includes an apparatus main body 101, a paper feed tray 102 for loading paper into the apparatus main body 101 on the front surface 112 of the apparatus main body 101, a paper discharge tray 103 for storing the paper on which an image is formed (recorded) loaded in the apparatus main body 101, an ink cartridge loading section 104, and an upper cover 111 on the upper surface of the apparatus main body 101. An operation section 105 such as operation keys and a display is arranged on the upper surface of the ink cartridge loading section 104. The ink cartridge loading section 104 has an openable and closable front cover 115 for detaching and attaching the ink cartridge 201.

[0102] Inside the apparatus main body 101, as shown in FIGS. 2 and 3 (not shown in the figure), 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 the left and right side plates (not shown), and is moved and scanned in the direction indicated by the arrow in FIG. 3 by a main scanning motor (not shown). On the carriage 133, a recording head 134 composed of four ink ejection heads for ejecting recording ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) is arranged with a plurality of ink ejection ports in a direction intersecting the main scanning direction, and is mounted with the ink droplet ejection direction facing downward. As the inkjet recording head constituting the recording head 134, those provided with energy generation means for ejecting ink such as a piezoelectric actuator such as a piezoelectric element, a thermal actuator using a phase change due to film boiling of a liquid using an electrothermal conversion element such as a heating resistor, a shape memory alloy actuator using a metal phase change due to a temperature change, and an electrostatic actuator using electrostatic force can be used.

[0103] In addition, the carriage 133 is equipped with sub-tanks 135 of various colors for supplying inks of various colors to the recording head 134. The sub-tanks 135 are replenished with the recording ink of the present invention supplied from the ink cartridge 201 of the present invention loaded in the ink cartridge loading section 104 through a recording ink supply tube (not shown). On the other hand, as a paper feeding unit for feeding the paper 142 stacked on the paper stacking section (platen) 141 of the paper feeding tray 102, it includes a semi-circular roller (paper feeding roller 143) for separating and feeding the paper 142 one by one from the paper stacking section 141, and a separation pad 144 facing the paper feeding roller 143 and made of a material with a large coefficient of friction. The separation pad 144 is biased toward the paper feeding roller 143 side. As a conveying unit for conveying the paper 142 fed from this paper feeding unit below the recording head 134, it includes a conveying belt 151 for electrostatically adsorbing and conveying the paper 142, a counter roller 152 for sandwiching and conveying the paper 142 sent from the paper feeding unit through the guide 145 between the conveying belt 151, a conveying guide 153 for deflecting the paper 142 sent in a substantially vertically upward direction by approximately 90° and guiding it along the conveying belt 151, and a tip pressure roller 155 biased toward the conveying belt 151 side by a pressing member 154. Also, a charging roller 156, which is a charging means for charging the surface of the conveying belt 151, is provided. The conveying belt 151 is an endless belt, stretched between a conveying roller 157 and a tension roller 158, and is capable of rotating in the belt conveying direction. This conveying belt 151 has, for example, a surface layer that serves as a paper adsorption surface formed of a resin material with a thickness of about 40 μm without resistance control, such as a copolymer of tetrafluoroethylene and ethylene (ETFE), and a back layer (medium resistance layer, ground layer) made of the same material as this surface layer and having resistance control by carbon. A guide member 161 is arranged on the back side of the conveying belt 151 corresponding to the printing area by the recording head 134. In addition, as a paper discharging unit for discharging the paper 142 recorded by the recording head 134, it includes a separation claw 171 for separating the paper 142 from the conveying belt 151, a paper discharging roller 172 and a paper discharging roller 173, and a paper discharging tray 103 is arranged below the paper discharging roller 172.

[0104] A duplex paper feeding unit 181 is detachably mounted on the back surface of the apparatus main body 101. The duplex paper feeding unit 181 takes in the paper 142 returned by the reverse rotation of the conveyance belt 151, reverses it, and feeds it again between the counter roller 152 and the conveyance belt 151. Note that a manual paper feeding portion 182 is provided on the upper surface of the duplex paper feeding unit 181. In this inkjet recording apparatus, the paper 142 is separated and fed one by one from the paper feeding portion, and the paper 142 fed substantially vertically upward is guided by the guide 145 and sandwiched between the conveyance belt 151 and the counter roller 152 for conveyance. Further, the leading end is guided by the conveyance guide 153 and pressed against the conveyance belt 151 by the leading end pressing roller 155, and the conveyance direction is changed by substantially 90°. At this time, the conveyance belt 151 is charged by the charging roller 156, and the paper 142 is electrostatically adsorbed to the conveyance belt 151 and conveyed. Therefore, while moving the carriage 133, the recording head 134 is driven according to the image signal, ink droplets are ejected onto the stopped paper 142 to record one line, and after the paper 142 is conveyed by a predetermined amount, the next line is recorded. When receiving a recording end signal or a signal indicating that the trailing end of the paper 142 has reached the recording area, the recording operation is terminated and the paper 142 is discharged to the paper discharge tray 103. When the remaining amount of ink in the sub-tank 135 reaches the end, a required amount of ink is replenished from the ink cartridge 201 to the sub-tank 135.

[0105] In this inkjet recording apparatus, when the recording ink in the ink cartridge 201 of the present invention is used up, the housing of the ink cartridge 201 can be disassembled and only the internal ink bag 241 can be replaced. Further, the ink cartridge 201 can supply the recording ink stably even when it is vertically placed and has a front loading configuration. Therefore, even when the upper part of the apparatus main body 101 is blocked and installed, for example, when it is stored in a rack, or when an object is placed on the upper surface of the apparatus main body 101, the ink cartridge 201 can be easily replaced.

[0106] Here, an example of applying the present invention to a serial type (shuttle type) inkjet recording apparatus scanned by a carriage has been described. However, the present invention can be similarly applied to a line type inkjet recording apparatus equipped with a line head.

[0107] The inkjet recording apparatus and the inkjet recording method of the present invention can be applied to various recordings by an inkjet recording method, and can be particularly preferably applied to, for example, an inkjet printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like.

[0108] (Ink cartridge) The ink cartridge of the present invention is formed by housing the ink of the present invention in a container and further having other members and the like appropriately selected as necessary.

[0109] The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, those having an ink bag formed of an aluminum laminate film, a resin film, or the like are preferably mentioned.

[0110] Next, the ink cartridge will be specifically described with reference to FIGS. 4 and 5, but the present invention is not limited thereto. FIG. 4 is a schematic diagram showing the ink cartridge 201, and FIG. 5 is a schematic diagram showing a modification of the ink cartridge of FIG. 4. As shown in FIG. 4, the ink is filled into the ink bag 241 from the ink inlet 242, and after exhausting the air, the ink inlet 242 is closed by fusion. In use, the needle of the ink jet recording apparatus main body 101 shown in FIG. 1 is inserted into the ink outlet 243 made of a rubber member, and the ink is supplied to the apparatus main body 101. The ink bag 241 is formed of a packaging member such as an airtight aluminum laminate film. As shown in FIG. 5, this ink bag 241 is usually housed in a plastic cartridge case 244 and is detachably attached to various ink jet recording apparatuses for use. The ink cartridge 201 of the present invention particularly preferably houses the ink of the present invention and is detachably attached to various ink jet recording apparatuses.

[0111] (Ink recording material) A recording material recorded by the ink jet recording apparatus of the present invention and the ink jet recording method of the present invention using the ink of the present invention is an ink recording material of the present invention. The ink recording material has an image formed on a recording medium using the ink of the present invention.

[0112] Examples of the recording medium include the same ones as those described in the item of (ink jet recording apparatus and ink jet recording method).

[0113] The ink recording material has high image quality, no bleeding, excellent stability over time, and can be suitably used for various purposes as various materials on which various prints or images are recorded.

Example

[0114] The present invention will be specifically described below by way of Preparation Examples, Production Examples, Comparative Production Examples, Examples, and Comparative Examples. However, the present invention is not limited to these Preparation Examples, Production Examples, and Examples. In the Preparation Examples, Production Examples, Comparative Production Examples, Examples, and Comparative Examples, "parts" and "%" indicate "parts by mass" and "mass %" unless otherwise specified.

[0115] (Preparation Example 1) <Preparation of Magenta Pigment-Containing Polymer Fine Particle Dispersion> -Preparation of Polymer Solution A- After thoroughly purging a 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube, and dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer, and 0.4 g of mercaptoethanol were mixed and heated to 65°C. Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxyethyl methacrylate, 36.0 g of styrene macromer, 3.6 g of mercaptoethanol, 2.4 g of azobis(methylvaleronitrile), and 18 g of methyl ethyl ketone were mixed to prepare a mixed solution, which was then added dropwise to the flask over 2.5 hours. After the addition, 0.8 g of azobis(methylvaleronitrile) and 18 g of methyl ethyl ketone were mixed to prepare a mixed solution, which was then added dropwise to the flask over 0.5 hour. Next, after aging at 65°C for 1 hour, 0.8 g of azobis(methylvaleronitrile) was added and aging was continued for another 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of Polymer Solution A with a concentration of 50%.

[0116] -Preparation of Magenta Pigment-Containing Polymer Fine Particle Dispersion- 28 g of the polymer solution A, 42 g of C.I. Pigment Red 122, 13.6 g of 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 13.6 g of ion-exchanged water were mixed and stirred well, and then kneaded using a roll mill. The obtained paste was put into 200 g of pure water, stirred well, and then methyl ethyl ketone and water were distilled off using an evaporator. In order to remove coarser particles, this dispersion was pressure-filtered through a polyvinylidene fluoride membrane filter with an average pore diameter of 5.0 μm to obtain a magenta pigment-containing polymer fine particle dispersion with a pigment content of 15% and a solid content concentration of 20%.

[0117] -Measurement of volume-average particle diameter (D 50 ) The obtained magenta pigment-containing polymer fine particle dispersion was diluted with pure water so that the solid content concentration of the polymer fine particles became 0.01%, and the pigment volume-average particle diameter (D 50 ) was measured using a particle size distribution measuring device (NanoTrac UPA-EX150, manufactured by Nikkiso Co., Ltd.). At this time, the particle refractive index was 1.51, the particle density was 1.4 g / cm 3 , and the parameters of pure water were used as the solvent parameters, and the measurement was carried out under the measurement conditions of 23°C. As a result, the volume-average particle diameter (D 50 ) of the polymer fine particles in the magenta pigment-containing polymer fine particle dispersion was 82.7 nm.

[0118] (Preparation Example 2) <Preparation of Cyan Pigment-Containing Polymer Fine Particle Dispersion> In the preparation of the magenta pigment-containing polymer fine particle dispersion of Preparation Example 1, a cyan pigment-containing polymer fine particle dispersion with a pigment content of 15% and a solid content concentration of 20% was obtained in the same manner as in Preparation Example 1, except that C.I. Pigment Red 122 was changed to C.I. Pigment Blue 15:3. The volume-average particle diameter (D 50 ) of the polymer fine particles in the obtained cyan pigment-containing polymer fine particle dispersion was measured in the same manner as in Preparation Example 1. As a result, the volume-average particle diameter (D 50) was 120.0 nm.

[0119] (Preparation Example 3) <Preparation of Silicone Emulsion 1> A mixture of 381.2 g of polydimethylsiloxane fluid (having a hydroxyl group at the terminal and a degree of polymerization of 35), 3.85 g of polymethylhydrogen siloxane (having a trimethylsiloxy group at the terminal, a viscosity of 0.13 Pa·s at 25°C, and a content of silicon-bonded hydrogen atoms of 1.6%), 15.9 g of a 30% aqueous sodium lauryl sulfate solution, and 186 g of distilled water was prepared. This mixture was processed twice using a laboratory single-stage homogenizer to make it homogeneous, and a uniform emulsion with a volume average particle diameter (D 50 ) of 1.1 μm was prepared. After adding 3.2 g of dodecylbenzenesulfonic acid to this emulsion, it was allowed to stand at 25°C for 24 hours for polymerization. Polymerization was terminated by adding a sufficient amount of diethylamine to raise the pH to 7 - 7.5. Thereby, Silicone Emulsion 1 (polydimethylsiloxane emulsion, volume average particle diameter (D 50 ) 1.1 μm) was obtained. Incidentally, the volume average particle diameter (D 50 ) of the silicone emulsion was measured using a particle size distribution measuring device (NanoTrac UPA-EX150, manufactured by Nikkiso Co., Ltd.).

[0120] (Preparation Example 4) In Preparation Example 3, except that the shear force of the homogenizer was changed, in the same manner as in Preparation Example 3, Silicone Emulsion 2 (polydimethylsiloxane emulsion, volume average particle diameter (D 50 ) 4.5 μm) was obtained.

[0121] (Preparation Example 5) In Preparation Example 3, except that the shear force of the homogenizer was changed, in the same manner as in Preparation Example 3, Silicone Emulsion 3 (polydimethylsiloxane emulsion, volume average particle diameter (D 50 ) 195 nm) was obtained.

[0122] (Preparation Example 6) In Preparation Example 3, a silicone emulsion 4 (polydimethylsiloxane emulsion, volume average particle diameter (D 50 ) 6.0 μm) was obtained in the same manner as in Preparation Example 3, except that the shear force of the homogenizer was changed.

[0123] (Production Examples 1 to 7 and Comparative Production Examples 1 to 5) (Preparation of Ink for Inkjet) Each ink for inkjet was prepared according to the following procedure. A pigment dispersion, a resin dispersion, an organic solvent, a surfactant, and water (pure) were mixed in the compositions and contents shown in Table 1-1 and Table 1-2 below, and stirred for 1 hour to mix uniformly. This dispersion was pressure-filtered through a polyvinylidene fluoride membrane filter with an average pore diameter of 5.0 μm to remove coarse particles and dust, thereby preparing inks for inkjet of Production Examples 1 to 7 and Comparative Production Examples 1 to 5. In Table 1-1 and Table 1-2 below, the pigment dispersion and the resin dispersion show the contents in terms of solid content. Also, the ratio [volume average particle diameter of colorant (D 50 ) / volume average particle diameter of silicone emulsion (D 50 )] shows the value up to the second decimal place, with the third decimal place rounded off.

[0124] -Measurement of Ink Viscosity- The viscosities of the inks for inkjet of Production Examples 1 to 7 and Comparative Production Examples 1 to 5 were measured at 25 °C using a viscometer (RE-550L, manufactured by Toki Sangyo Co., Ltd.). The results are shown in Table 1-1 and Table 1-2 below.

[0125]

Table 1-1

[0126]

Table 1-2

[0127] ※ As the "polyurethane emulsion" in Table 1-1 and Table 1-2 above, the product name: Yucoat UA-3945 (solid content concentration 38.4%, volume average particle diameter (D 50 ) 35 nm, manufactured by Sanyo Chemical Industries, Ltd.) was used. ※ As the "silicone surfactant 1" in Table 1-1 and Table 1-2 above, the product name: KF-6043 (PEG-10 dimethicone, silicone linear polyether modified silicone, manufactured by Shin-Etsu Chemical Co., Ltd.) was used. ※ In Table 1-1 and Table 1-2 above, "silicone surfactant 2" is a compound represented by the following general formula (1), and the product name: TEGO (registered trademark) Wet 270 (manufactured by Evonik Industries) was used. [Chemical formula] (However, in the above general formula (1), m represents an integer from 0 to 7, and n represents an integer from 2 to 15.) ※ As the "fluorosurfactant 1" in Table 1-1 and Table 1-2 above, the product name: Ftergent 250 (manufactured by Neos Co., Ltd.) was used.

[0128] (Examples 1 to 11 and Comparative Examples 1 to 5) Each inkjet ink of Production Examples 1 to 7 and Comparative Production Examples 1 to 5 and an inkjet recording apparatus having a filter shown in Table 2 below in the ink flow path were used in the combinations shown in Table 2 below, and "initial filling property", "bubbles in the cap", "discharge stability", and "liquid passing property" were evaluated by the following evaluation methods. The results are shown in Table 2 below. Note that the inkjet recording apparatus used in the following evaluation has a filter in the ink flow path. The material of the filter is metal fiber, and the average pore diameter and thickness of the filter are shown in Table 2 below. The filter was provided between the ink cartridge and the ink discharge head.

[0129] [Initial filling property] The following evaluation was carried out under environmental conditions adjusted to 23 ± 0.5 °C and 50 ± 5% RH. After filling the inkjet recording apparatus (IPSiO GXe-5500, manufactured by Ricoh Company, Ltd.) with a 10% aqueous propylene glycol solution, each of the inkjet inks of Production Examples 1 to 7 and Comparative Production Examples 1 to 5 was filled. Using this, when printing a nozzle check pattern, the number of nozzle cleaning times until the number of non-ejecting nozzles became 0 was measured, and the "initial fillability" of Examples 1 to 11 and Comparative Examples 1 to 5 was evaluated based on the following evaluation criteria. - Evaluation Criteria for Initial Fillability - A: The number of non-ejecting nozzles becomes 0 after 1 to 2 nozzle cleanings B: The number of non-ejecting nozzles becomes 0 after 3 to 10 nozzle cleanings

[0130] <Bubbles in the Cap> Under environmental conditions adjusted to 23 ± 0.5°C and 50 ± 5% RH, the following evaluations were performed. Each of the inkjet inks of Production Examples 1 to 7 and Comparative Production Examples 1 to 5 was filled into an inkjet recording apparatus (IPSiO GXe-5500, manufactured by Ricoh Company, Ltd.). Using this, after performing ink refresh (an operation of discarding the ink accumulated in the ink ejection head and sucking up new ink from the cartridge) 5 times, the inside of the head suction cap was visually observed, and the "bubbles in the cap" of Examples 1 to 11 and Comparative Examples 1 to 5 was evaluated based on the following evaluation criteria. - Evaluation Criteria for Initial Fillability - A: No bubbles in the cap B: Bubbles only at the bottom of the cap C: Bubbles throughout the cap

[0131] <Ejection Stability> Under environmental conditions adjusted to 32 ± 0.5°C and 50 ± 5% RH, the following evaluations were performed. After filling the inkjet recording apparatus (IPSiO GXe-5500, manufactured by Ricoh Company, Ltd.) with the inkjet inks of Production Examples 1 to 7 and Comparative Production Examples 1 to 5, it was left standing for 6 hours with the cap open. After performing nozzle cleaning once, a nozzle check pattern was printed to confirm the presence or absence of non-ejecting nozzles. Also, when there were non-ejecting nozzles, nozzle cleaning was further performed twice, and the presence or absence of non-ejecting nozzles was confirmed. When there were still non-ejecting nozzles after performing nozzle cleaning a total of three times, ink refreshing was further performed once, and the presence or absence of non-ejecting nozzles was confirmed. Based on the above operations, the "discharge stability" of Examples 1 to 11 and Comparative Examples 1 to 5 was evaluated according to the following evaluation criteria. - Evaluation Criteria for Discharge Stability - A: After performing nozzle cleaning once, there are no non-ejecting nozzles B: After performing nozzle cleaning once, there are non-ejecting nozzles, and the non-ejection is restored within three times of nozzle cleaning C: After performing nozzle cleaning once, there are non-ejecting nozzles, and the non-ejection is restored by three times of nozzle cleaning and once of nozzle refreshing

[0132] <Liquid Flow Property> The following evaluation was carried out under environmental conditions adjusted to 23 ± 0.5°C and 50 ± 5% RH. After passing 5 kg of the inkjet inks of Production Examples 1 to 7 and Comparative Production Examples 1 to 5 through the inkjet recording apparatus (IPSiO GXe-5500, manufactured by Ricoh Company, Ltd.) during the ink filling operation, a nozzle check pattern was printed to confirm the presence or absence of non-ejecting nozzles. Also, when there were non-ejecting nozzles, nozzle cleaning was further performed three times, and the presence or absence of non-ejecting nozzles was confirmed. Based on the above operations, the "liquid flow property" of Examples 1 to 11 and Comparative Examples 1 to 5 was evaluated according to the following evaluation criteria. - Evaluation Criteria for Liquid Flow Property - A: After performing nozzle cleaning once, there are no non-ejecting nozzles B: After performing nozzle cleaning once, there are non-ejecting nozzles, and the non-ejection is restored within three times of nozzle cleaning C: Ink ejection is impossible

[0133] [Table 2]

[0134] Examples of aspects of the present invention include the following. <1> An ink for use in an inkjet recording device having a filter in an ink flow path, Contains water, a coloring material, a silicone surfactant, and silicone compound particles; The volume average particle diameter (D 50 ) is 1.01 μm to 5.00 μm, and the content of the silicone compound particles is 0.01% by mass to 0.20% by mass. <2> The silicone surfactant contains a surfactant represented by the following general formula (1): <1> The ink is as described in [ka] (In the general formula (1), m represents an integer of 0 to 7, and n represents an integer of 2 to 15.) <3> The volume average particle diameter (D 50 ) and the volume average particle diameter (D 50 ) [Volume average particle diameter of color material (D 50 ) / Volume average particle size of silicone compound particles (D 50 ) is in the range of 0.02 to 0.1 <1> from <2> The ink according to any one of claims 1 to 5, <4> The above <1> from <3> An ink according to any one of the preceding claims, A filter having an average pore size of 4 μm to 22 μm is provided in the ink flow path. The ink jet recording apparatus is characterized by having the above features. <5> The above <1> from <3> and causing the ink to fly onto a recording medium to form an image. <6> An ink cartridge characterized in that the ink according to any one of <1> to <3> is contained in a container. <7> An ink recording article characterized in that it has an image recorded by the ink according to any one of <1> to <3> on a recording medium.

[0135] The ink according to any one of <1> to <3>, the inkjet recording apparatus according to <4>, the inkjet recording method according to <5>, the ink cartridge according to <6>, and the ink recording article according to <7> can solve the above-described various problems in the prior art and achieve the object of the present invention.

Industrial Applicability

[0136] The ink of the present invention is excellent in dischargeability during ink filling, defoaming property of the ink, discharge stability, and ink flowability. Therefore, when printing on a recording medium, particularly when printing on coated paper, it is excellent in fixability and storage stability and can be suitably used for an inkjet recording apparatus, an inkjet recording method, an ink cartridge, and an ink recording article. Further, the inkjet recording apparatus and the inkjet recording method of the present invention can be applied to various recordings by an inkjet recording method, and are particularly suitably applicable to, for example, an inkjet printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like.

Explanation of Signs

[0137] 101 Apparatus main body 102 Paper feed tray 103 Paper discharge tray 104 Ink cartridge loading section 105 Operation section 111 Upper cover 112 Front surface 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Sub-tank 141 Paper loading section 142 Paper 143 Paper feed roller 144 Separation pad 145 Guide 151 Conveyor belt 152 Counter roller 153 Conveyor guide 154 Pressing member 155 Tip pressure roller 156 Charging roller 157 Conveyor roller 158 Tension roller 161 Guide member 171 Separation claw 172 Paper discharge roller 173 Paper discharge roller 181 Duplex paper feed unit 182 Manual paper feed section 201 Ink cartridge 241 Ink bag 242 Ink injection port 243 Ink discharge port 244 Cartridge case

Prior art documents

Patent documents

[0138]

Patent Document 1

Claims

1. An ink used in an inkjet recording apparatus having a filter in an ink flow path, containing water, a coloring material, a silicone surfactant, and silicone compound particles, The volume average particle diameter (D ５０ ) of the silicone compound particles is 1.01 μm to 5.00 μm, and the content of the silicone compound particles is 0.01% by mass to 0.20% by mass. The ink is characterized by this.

2. The ink according to claim 1, wherein the silicone surfactant contains a surfactant represented by the following general formula (1). 【Chemical 1】 (However, in the general formula (1), m represents an integer of 0 to 7, and n represents an integer of 2 to 15.)

3. The volume average particle diameter (D ５０ ), and the volume average particle diameter (D ５０ ) of the silicone compound particles, and the ratio [volume average particle diameter of the colorant (D ５０ ) / volume average particle diameter of the silicone compound particles (D ５０ )] is in the range of 0.02 to 0.

1. The ink according to any one of claims 1 to 2.

4. An inkjet recording apparatus comprising the ink according to any one of claims 1 to 3, and a filter having an average pore diameter of 4 μm to 22 μm in the ink flow path. ​

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