Inkjet printing device and inkjet printing method

Abstract

To provide an inkjet printing device which can solve such a problem that bubbles are generated in an ink supply passage or in a cap upon ink filling or upon ink passage and is excellent in ink ejection property and ink passage property.SOLUTION: An inkjet printing device includes ink, an inkjet head, an ink storage container and a filter provided in an ink supply path. Therein, the ink contains water, acetylene compound and alkylene glycol ether, the filter has pores, a pore size of the pores is 5 μm or more and 20 μm or less and thickness of the filter is 0.1 mm or more and 0.5 mm or less.

Description

[Technical Field]

[0001] The present invention relates to an inkjet printing apparatus and an inkjet printing method. [Background technology]

[0002] The inkjet printing method has the advantage that the process is simpler than other printing methods, making it easy to produce full color, and high-resolution images can be obtained even with a device with a simple configuration. Inkjet inks include dye-based inks in which various water-soluble dyes are dissolved in water or a mixture of water and a water-soluble humectant, and pigment inks in which pigments are dispersed in a liquid containing water or an organic solvent.

[0003] In recent years, stricter environmental regulations have led to stricter regulations on fluorosurfactants, and the use of fluorosurfactants is becoming more and more restricted. Because fluorosurfactants have excellent properties such as excellent substrate wetting and foam removal, it is difficult to select alternative materials. From the perspective of environmental impact, hydrocarbon surfactants are superior to fluorosurfactants or silicone surfactants. For example, Patent Document 1 uses a hydrocarbon surfactant with an acetylene structure, which has excellent wetting and foaming properties. DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] However, the hydrocarbon surfactant disclosed in Patent Document 1 does not have sufficient defoaming properties. If sufficient defoaming properties are not ensured, problems such as bubbles forming in the ink supply path when filling or passing the ink can occur, making it impossible to stably eject the ink, or bubbles forming in the cap that sucks up the remaining ink in the head can adhere to the ink ejection head, making it impossible to stably eject the ink, can occur.

[0005] The present invention aims to provide an inkjet printing device that can solve the problem of bubbles forming in the ink supply path or cap when filling or passing ink, and that has excellent ink ejection properties and ink permeability. [Means for solving the problem]

[0006] The inkjet printing apparatus of the present invention as a means for solving the above-mentioned problems is an inkjet printing apparatus having an ink, an inkjet head, an ink storage container, and a filter provided in an ink supply path, wherein the ink is a mixture of water, an acetylene compound, and an alkylene glycol ether. , organic solvent Contains the organic solvent contains 1,2-propanediol and glycerin, The filter has pores, the pores have a diameter of 5 μm or more and 20 μm or less, the filter has a thickness of 0.1 mm or more and 0.5 mm or less, and the ink contains a silicone emulsion. [Effects of the Invention]

[0007] According to the present invention, it is possible to solve the problem of bubbles being generated in the ink supply path or in the cap when filling or passing ink, and to provide an inkjet printing device with excellent ink ejection properties and ink permeability. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic view showing an example of an ink cartridge in an inkjet printing apparatus of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a modified example of the ink cartridge in the inkjet printing apparatus of the present invention. [Figure 3] FIG. 3 is a schematic diagram showing an example of the inkjet printing apparatus of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view of an example of the inkjet printing apparatus of the present invention. [Figure 5] FIG. 5 is a schematic diagram showing an example of the carriage and its surroundings in the inkjet printing apparatus of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments of the present invention will be described in more detail.

[0010] (ink) The ink used in the present invention contains water, an acetylene compound and an alkylene glycol ether as surfactants, and may further contain other organic solvents, wetting agents, colorants, penetrants, defoamers, rust inhibitors, preservatives, water-dispersible resins, and other components as required.

[0011] <Surfactant> The ink used in the present invention contains an acetylene compound and an alkylene glycol ether as the surfactant, which improves the initial filling property and the defoaming effect. As the acetylene compound, for example, a compound having an acetylene structure such as 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol or 2,4,7,9-tetramethyl-5-decyne-4,7-diol can be used appropriately.

[0012] Examples of alkylene glycol ethers that can be used include compounds such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol methyl ethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol-n-propyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tripropylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, and octaethylene glycol monoundecyl ether, as well as ready-made surfactants such as Softanol EP-7025 (polyoxyalkylene alkyl ether, manufactured by Nippon Shokubai Co., Ltd.). Among these, octaethylene glycol monoundecyl ether and Softanol EP-7025 are preferred.

[0013] A surfactant that does not impair dispersion stability depending on the type of colorant or the combination of wetting agents, has low surface tension, and has high penetration and leveling properties is preferred. A mixture of at least one surfactant selected from anionic surfactants and nonionic surfactants having an acetylene structure and one or more surfactants having a hydrocarbon EO chain attached and not having an acetylene structure is used. These surfactants can be used in combination of two or more. The content of the surfactant in the ink is preferably 0.01% by mass or more and 3% by mass or less, and more preferably 0.1% by mass or more and 1% by mass or less. The mass ratio (B / A) of the acetylene compound (A) to the alkylene glycol ether (B) is preferably 2 or more and 5 or less. From the viewpoint of suppressing the generation of bubbles inside the cap that sucks up residual ink inside the head, the acetylene compound is preferably a compound having 16 carbon atoms.

[0014] -Organic solvents- The organic solvent is preferably water-soluble, and the content of the water-soluble organic solvent is preferably 35% by mass or more and 50% by mass or less from the viewpoint of improving ejection reliability.

[0015] --Wetting agent-- In the present invention, a humectant is a highly hygroscopic organic solvent that dissolves in water. When a humectant is added to an ink, it remains on the surface of the ink or recording medium, retaining moisture and suppressing evaporation of the moisture. Other wetting agents include, for example, polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, ethylene carbonate, and sugars. Specific examples include 1,2,3-butanetriol (bp 175°C / 33hPa), 1,2,4-butanetriol (bp 190-191°C / 24hPa), glycerin (bp 290°C), diglycerin (bp 2 70°C / 20hPa), triethylene glycol (bp 285°C), tetraethylene glycol (bp 324-330°C), diethylene glycol (bp 245°C), 1,3-butanediol (bp 203-204°C), 3-methyl-1,3-butanediol (bp 203°C), β-methoxy-N,N-dimethylpropionamide (bp 216°C), 2-pyrrolidone (bp 245°C), 1,3-dimethyl-2-imidazolidinone (bp 225°C), etc.

[0016] Other options that can be used include: 3-Methyl-1,3-butanediol (bp 203°C), isobutyl diglycol (bp 220°C), tripropylene glycol monomethyl ether (bp 242°C), 2-(2-isopropyloxyethoxy)ethanol (bp 207°C), isopropyl glycol (bp 142°C), diethyl diglycol (bp 189°C), propyl propylene glycol (bp 150°C), tributyl citrate (bp 234°C), propyl propylene diglycol (bp 220°C), butyl propylene glycol (bp 170°C), butyl propylene diglycol (bp 212°C), methyl propylene glycol acetate (bp 146°C), triethylene glycol dimethyl ether (bp 216°C), N,N-dimethylacrylamide (bp 171°C), N,N-diethylacrylamide (bp 56°C / 3mmHg), dipropylene glycol (bp 232°C), 1,5-pentanediol (bp 242°C), propylene glycol (bp 187°C), 2-methyl-2,4-pentanediol (bp 197°C), ethylene glycol (bp 196-198°C), tripropylene glycol (bp 267°C), hexylene glycol (bp 197°C), polyethylene glycol (viscous liquid to solid), polypropylene glycol (bp 187°C), 1,6-hexanediol (bp 253-260°C), 1,2,6-hexanetriol (bp 178°C), etc.

[0017] Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether (bp 135°C), ethylene glycol monobutyl ether (bp 171°C), diethylene glycol monomethyl ether (bp 194°C), diethylene glycol monoethyl ether (bp 197°C), diethylene glycol monobutyl ether (bp 231°C), ethylene glycol mono-2-ethylhexyl ether (bp 229°C), and propylene glycol monoethyl ether (bp 132°C). Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether (bp 237° C.) and ethylene glycol monobenzyl ether. Examples of the nitrogen-containing heterocyclic compound include N-methyl-2-pyrrolidone (bp 202° C.), 1,3-dimethyl-2-imidazolidinone (bp 226° C.), ε-caprolactam (bp 270° C.), and γ-butyrolactone (bp 204-205° C.). Examples of the amides include formamide (bp 210° C.), N-methylformamide (bp 199-201° C.), N,N-dimethylformamide (bp 153° C.), and N,N-diethylformamide (bp 176-177° C.). Examples of the amines include monoethanolamine (bp 170°C), diethanolamine (bp 268°C), triethanolamine (bp 360°C), N,N-dimethylmonoethanolamine (bp 139°C), N-methyldiethanolamine (bp 243°C), N-methylethanolamine (bp 159°C), N-phenylethanolamine (bp 282-287°C), and 3-aminopropyldiethylamine (bp 169°C). Examples of the sulfur-containing compounds include dimethyl sulfoxide (bp 139° C.), sulfolane (bp 285° C.), and thiodiglycol (bp 282° C.).

[0018] As other solid water-soluble organic solvents, sugars and the like are preferred. Examples of such sugars include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, etc. Specific examples include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, etc. Here, the term "polysaccharides" refers to sugars in a broad sense, and is used to mean substances that are widely present in nature, such as α-cyclodextrin and cellulose. Furthermore, derivatives of these sugars include reducing sugars of the above-mentioned sugars (for example, sugar alcohols (general formula: HOCH2(CHOH) nExamples of the sugar alcohol include hydroxybenzoates (e.g., hydroxybenzoates represented by CHOH (where n is an integer of 2 to 5)), sugar oxides (e.g., aldonic acid, uronic acid, etc.), amino acids, and thioacids. Among these, sugar alcohols are preferred, and specific examples include maltitol and sorbitol.

[0019] -Coloring materials- As the coloring material, a dye or a pigment is used. Examples of pigments include organic pigments such as phthalocyanine-based, anthraquinone-based, dioxazine-based, indigo-based, thioindigo-based, perylene-based, isoindolenon-based, aniline black, azomethine-based, and rhodamine B lake pigments, and inorganic pigments such as carbon black, iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, Prussian blue, cadmium red, chrome yellow, and metal powder. Specific examples of black pigments include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper oxide, iron oxide (CI Pigment Black 11), and titanium oxide; and organic pigments such as aniline black (CI Pigment Black 1). Specific examples of yellow pigments include CI 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, and 185. Specific examples of magenta pigments include CI Pigment Violet 19, CI Pigment Red 1, 2, 3, 5, 7, 9, 12, 17, 22 (Brilliant Fast 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 Lake), 83, 88, 92, 97, 101 (Red ochre), 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, etc. Specific examples of cyan pigments include CI 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, Vat Blue 4, and Vat Blue 60. Specific examples of intermediate color pigments for red, green, and blue include CI Pigment Red 177, 194, and 224, CI Pigment Orange 16, 36, 43, 51, 55, 59, 61, and 71, CI Pigment Violet 3, 19, 23, 29, 30, 37, 40, and 50, and CI Pigment Green 7 and 36.

[0020] Of the above pigments, carbon black is particularly preferred as a black pigment. Carbon black produced by the furnace method or the channel method has a primary particle size of 15 nm to 40 nm and a specific surface area of ​​50 m2 as measured by the BET adsorption method. 2 / g~300m 2 / g, DBP oil absorption of 40 ml / 100 g to 150 ml / 100 g, volatile content of 0.5% to 10%, and pH of 2 to 9 are used, and acidic carbon black with a pH of 6 or less is particularly preferred for its high concentration. As the color pigment, particularly preferred are Pigment Yellow 13, 17, 55, 74, 93, 97, 98, 110, 128, 139, 147, 150, 151, 154, 155, 180, and 185, Pigment Red 122, 202, and 209, Pigment Violet 19, and Pigment Blue 15:3 and 15:4.

[0021] The average particle size of the pigment is not particularly limited, but is preferably 20 nm to 200 nm, more preferably 30 nm to 150 nm, and even more preferably 50 nm to 100 nm. The average particle size of the pigment in the present invention was measured using a Microtrac UPA-150 manufactured by Nikkiso Co., Ltd., using a sample diluted with pure water so that the pigment concentration in the measurement sample was 0.01 mass %, with a particle refractive index of 1.51 and a particle density of 1.4 g / cm. 3 This refers to the 50% average particle size (D50) measured at 23°C using the parameters of pure water as the solvent parameters. The pigment concentration in the ink is preferably 2% by mass to 15% by mass, more preferably 3% by mass to 12% by mass, and even more preferably 4% by mass to 10% by mass.

[0022] -Dispersant- Pigment inks generally use dispersants, usually nonionic or anionic surfactant dispersants, which are selected appropriately depending on the type of pigment or ink formulation. Examples of nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether, polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether, polyoxyethylene-α-naphthyl ether, polyoxyethylene-β-naphthyl ether, polyoxyethylene monostyrylphenyl ether, polyoxyethylene distyrylphenyl ether, polyoxyethylene alkylnaphthyl ether, polyoxyethylene monostyrylnaphthyl ether, polyoxyethylene distyrylnaphthyl ether, and polyoxyethylene polyoxypropylene block copolymers. Also useful are surfactants in which part of the polyoxyethylene in these surfactants is replaced with polyoxypropylene, and surfactants in which a compound having an aromatic ring, such as polyoxyethylene alkylphenyl ether, is condensed with formalin or the like. The HLB of the nonionic surfactant is preferably 12 to 19.5, and more preferably 13 to 19.

[0023] Examples of anionic surfactants include polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene monostyryl phenyl ether sulfates, polyoxyethylene distyryl phenyl ether sulfates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, polyoxyethylene monostyryl phenyl ether phosphates, polyoxyethylene distyryl phenyl ether phosphates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl phenyl ether carboxylates, polyoxyethylene monostyryl phenyl ether carboxylates, polyoxyethylene distyryl phenyl ether carboxylates, naphthalene sulfonate formalin condensates, melamine sulfonate formalin condensates, dialkyl sulfosuccinate salts, alkyl sulfosuccinate disalts, polyoxyethylene alkyl sulfosuccinate disalts, alkyl sulfoacetates, α-olefin sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfonates, N-acyl amino acid salts, acylated peptides, and soaps. Among these, sulfates or phosphates of polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, and polyoxyethylene distyryl phenyl ethers are particularly preferred.

[0024] The amount of surfactant-based dispersant added is preferably 10% by mass or more and 50% by mass or less of the pigment.

[0025] -resin- It is preferable to add a resin to the ink used in the present invention, mainly for the purpose of improving the abrasion resistance of the image and improving storage stability when a pigment is used as the colorant. To improve the abrasion resistance of the image, emulsions of acrylic resin, styrene-acrylic resin, acrylic silicone resin, and fluororesin are preferred, while polyurethane resin, acrylic resin, styrene-acrylic resin, and acrylic silicone resin are preferred to improve storage stability. However, since there are few resins that can simultaneously improve the abrasion resistance of the image and the storage stability, two types of resins may be used in combination. These resins can be selected from commercially available products as needed and used. The resin is preferably in an emulsion state, and the emulsion state resin is referred to as a resin emulsion.

[0026] Representative examples of resin emulsions are given below. --Urethane resin emulsion-- The urethane resin in the urethane resin emulsion is obtained by polymerizing a polyisocyanate with a polyether polyol, a polyester polyol, a polylactone polyol, a polycarbonate polyol, etc. Examples of polyisocyanates 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, aralkyl diisocyanate compounds such as xylylene diisocyanate and tetramethylxylene diisocyanate, aromatic diisocyanate compounds such as toluylene diisocyanate and phenylmethane diisocyanate, and modified products of these diisocyanates (carbodiimide, uretdione, uretoimine-containing modified products, etc.). Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol. Examples of polyester polyols include polyethylene adipate, polybutylene adipate, polyneopentyl adipate, poly-3-methylpentyl adipate, polyethylene / butylene adipate, and polyneopentyl / hexyl adipate. Examples of polylactone polyols include polycaprolactone diol and polyomega hydroxycaproic acid polyol. Polycarbonate polyols include those known in the art, such as the products obtained by reacting diols such as propanediol-(1,3), butanediol-(1,4), hexanediol-(1,6), diethylene glycol, triethylene glycol, tetraethylene glycol, with phosgene and a diaryl carbonate such as diphenyl carbonate or a cyclic carbonate such as ethylene carbonate or propylene carbonate.

[0027] --Acrylic resin emulsion-- The acrylic resin in the acrylic resin emulsion is obtained by polymerizing an acrylic monomer alone or copolymerizing it with other monomers. Acrylic monomers 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, methacrylate Examples of the methacrylate include 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, and methacrylonitrile. Examples of other monomers 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, and divinylbenzene, unsaturated carboxylic acids such as itaconic acid and maleic acid, N-substituted maleimide, maleic anhydride, vinyl ketone, vinyl acetate, and vinylidene chloride. As the acrylic resin emulsion, a silicone emulsion is particularly preferable from the viewpoint of suppressing the generation of bubbles in the cap that sucks the residual ink in the head and improving the ejection stability.

[0028] The resin emulsion exhibits even better water dispersibility by introducing ionic groups into the resin. Examples of such ionic groups include sulfonic acid groups, carboxylic acid groups, sulfate groups, phosphate groups, phosphonic acid groups, and phosphinic acid groups, as well as alkali metal salts, alkaline earth metal salts, ammonium salts, and primary, secondary, and tertiary amine groups thereof. Among these, alkali metal carboxylate salts, ammonium carboxylate salts, alkali metal sulfonate salts, and ammonium sulfonate salts are preferred, with alkali metal sulfonate salts and ammonium sulfonate salts being particularly preferred in terms of water dispersion stability. The introduction of ionic groups is achieved by adding a monomer having an ionic group during resin synthesis. The preferred salts are Li, K, or Na salts.

[0029] -Penetrating agent- The ink used in the present invention may contain a penetrant, which improves the ink's permeability into the recording medium and improves dot filling. The penetrating agent may contain at least one polyol compound or glycol ether compound having 8 to 11 carbon atoms. These preferably have a solubility of 0.2% by mass or more and 5.0% by mass or less in water at 25° C. Among these, 2-ethyl-1,3-hexanediol [solubility: 4.2% (25° C.)] and 2,2,4-trimethyl-1,3-pentanediol [solubility: 2.0% (25° C.)] are particularly preferred. Other polyol compounds include aliphatic diols such as 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, and 5-hexene-1,2-diol. Other penetrants that can be used in combination are not particularly limited as long as they are soluble in the ink and can be adjusted to have the desired physical properties, and can be selected appropriately depending on the purpose. Examples of such penetrants include alkyl and aryl ethers of polyhydric alcohols such as diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, and tetraethylene glycol chlorophenyl ether, and lower alcohols such as ethanol.

[0030] The content of the penetrant in the ink is preferably 0.1% by mass or more and 4.0% by mass or less, from the viewpoint of the ink permeability into the recording medium and dot filling.

[0031] In addition to the above-mentioned additives, conventionally known additives such as pH adjusters, antiseptics and fungicides, anticorrosives, and chelating agents may be added to the ink used in the present invention.

[0032] - pH adjuster - The pH adjuster is added to stabilize the dispersion state of the ink by keeping it alkaline, thereby stabilizing ejection. There are no particular restrictions on the pH adjuster, and it can be selected appropriately depending on the purpose, as long as it can adjust the pH without adversely affecting the ink being prepared. From the viewpoints of preventing interactions caused by reactions between the ink and the inkjet head or ink supply unit, and improving ejection stability, it is preferable that the pH be 11 or less. The pH adjuster preferably contains an alcohol amine, an alkali metal hydroxide, an ammonium hydroxide, a phosphonium hydroxide, or an alkali metal carbonate.

[0033] Examples of alcohol amines include diethanolamine, triethanolamine, and 2-amino-2-ethyl-1,3-propanediol. Examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of ammonium hydroxides include ammonium hydroxide and quaternary ammonium hydroxide. Examples of phosphonium hydroxides include quaternary phosphonium hydroxide. Examples of alkali metal carbonates include lithium carbonate, sodium carbonate, and potassium carbonate.

[0034] -Preservatives- Examples of preservatives include sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, and sodium pentachlorophenol.

[0035] -Rust inhibitor- Examples of the rust inhibitor include acid sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[0036] -Chelating reagents- Examples of the chelating agent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uramildiacetate.

[0037] The ink used in the present invention is prepared by dispersing or dissolving water, an acetylene compound, an alkylene glycol ether, and optionally other organic solvents, wetting agents, colorants, penetrants, antifoaming agents, rust inhibitors, preservatives, water-dispersible resins, and other components in an aqueous medium, and then stirring and mixing as necessary. The dispersion can be carried out using, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc., and the stirring and mixing can be carried out using a stirrer with a conventional stirring blade, a magnetic stirrer, a high-speed disperser, etc.

[0038] The physical properties of the ink used in the present invention are not particularly limited and can be appropriately selected depending on the purpose. For example, it is preferable that the viscosity, surface tension, etc. are within the following ranges. The viscosity of the ink at 25° C. is preferably 5 mPa·s or more from the viewpoint of improving print density and character quality, and is preferably 15 mPa·s or less from the viewpoint of ejection stability. The viscosity can be measured at 25°C using, for example, a viscometer (RL-500, manufactured by Toki Sangyo Co., Ltd.). The surface tension of the ink is preferably 35 mN / m or less at 25° C., and more preferably 32 mN / m or less, from the viewpoint of improving the leveling of the ink on the recording medium.

[0039] The color of the ink used in the present invention is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include yellow, magenta, cyan, black, etc. When recording is performed using an ink set that combines two or more of these colors, a multicolor image can be formed, and when recording is performed using an ink set that combines all colors, a full-color image can be formed.

[0040] The ink used in the present invention can be used well in printers equipped with any type of inkjet head, such as a so-called piezo-type inkjet head that uses a piezoelectric element as pressure generating means to pressurize the ink in the ink flow path, thereby deforming a vibration plate that forms the wall of the ink flow path, changing the internal volume of the ink flow path and ejecting ink droplets (Japanese Patent Laid-Open No. 2-51734), a so-called thermal-type inkjet head that uses a heating resistor to heat the ink in the ink flow path and generate bubbles (Japanese Patent Laid-Open No. 61-59911), or an electrostatic-type inkjet head that has a vibration plate that forms the wall of the ink flow path and an electrode arranged opposite each other, and which changes the internal volume of the ink flow path by deforming the vibration plate using electrostatic force generated between the vibration plate and the electrode, thereby ejecting ink droplets (Japanese Patent Laid-Open No. 6-71882).

[0041] <filter> The ink supply unit and inkjet printing device according to the present invention are provided with at least one filter in an ink supply path that supplies ink. The ink supply path in this invention refers to the path through which ink passes from the ink storage bag (ink cartridge) to the nozzle of the head where it is ejected. The filter has holes. The filter pore size is preferably 5 μm or more and 20 μm or less from the viewpoint of improving ejection stability, and 10 μm or more and 20 μm or less from the viewpoint of "suppressing the generation of bubbles during liquid passage." The thickness of the filter is 0.1 mm or more and 0.5 mm or less from the viewpoint of improving ejection stability.

[0042] The filter is in constant contact with ink, and is therefore preferably made of stainless steel or polyimide from the viewpoint of corrosion resistance, and is particularly preferably made of austenitic stainless steel, more preferably SUS304, SUS316, or SUS316L, because of its excellent corrosion resistance. The filter preferably contains any one selected from SUS304, SUS316, and SUS316L, and more preferably consists of any one of these. The shape of the filter used in the present invention is not particularly limited, and any known filter that meets the requirements can be used. Among these, filters in which multiple holes are drilled into a stainless steel or polyimide plate using a punch or laser, sintered filters made by laminating stainless steel fibers in a felt-like form and sintering them, and twill weave filters made by weaving stainless steel fibers are used. The term "filter with multiple holes" used here refers to a filter in which multiple holes are drilled through a plate-shaped filter substrate from the upstream surface in the ink supply direction to the downstream surface in the ink supply direction. In particular, a sintered filter made by laminating stainless steel fibers into a felt-like shape and sintering them, or a twill weave filter made by weaving stainless steel fibers into a twill weave, is preferred, as it allows for an inkjet printing device or ink supply unit with longer-term ejection reliability to be obtained.

[0043] The filter may be installed in any of the following locations: the head, the liquid passage (ink supply tube) between the head and subtank, the subtank, the liquid passage between the ink cartridge and subtank, or the ink cartridge, but it is preferably installed in a location from the ink ejection port from the subtank to the head just before the ink enters the head. By installing the filter in this location, it is possible to prevent foreign matter that has been mixed in the subtank from entering the head. When installing it in the head, it is preferable to install it in front of the common liquid chamber. This is because, in addition to the reasons mentioned above, there is only one filter, so the structure is not complicated.

[0044] The ink used in the present invention can be suitably used in various fields, such as inkjet recording ink, fountain pens, ballpoint pens, magic markers, and felt-tip pens, and is particularly suitable for use in image forming devices (printers, etc.) using an inkjet recording method. For example, the ink can be used in printers and the like that have a function of heating the recording medium and the ink to 50°C or higher and 200°C or lower before or after printing to promote print fixation, and is particularly suitable for use in the ink cartridge, inkjet printing method, inkjet printing device, and ink recorded matter of the present invention described below.

[0045] -Recording Media- As the recording medium, a coated paper based on photographic printing paper, which has a coating layer and is excellent in gloss, is preferably used. It is also suitable for use with plain paper that does not have a coating layer, and plain paper that is generally used as copy paper and has a sizing degree of 10S or more and an air permeability of 5S to 50S is preferred.

[0046] <Ink cartridges> The ink cartridge used in the present invention contains the ink used in the present invention in a container, and further contains other members appropriately selected as necessary. The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected depending on the purpose. For example, a container having at least an ink bag formed from an aluminum laminate film, a resin film, etc. is suitable.

[0047] Next, the ink cartridge will be described with reference to Figures 1 and 2. Here, Figure 1 is a schematic diagram showing an ink cartridge 201 in a printing device of the present invention, and Figure 2 is a schematic diagram showing a modified example of the ink cartridge of Figure 1. As shown in FIG. 1, the ink of the present invention is filled into an ink bag 241 through an ink inlet 242, and after the ink is exhausted, the ink inlet 242 is sealed by fusion. During use, a needle of the inkjet printing apparatus main body 101, which will be described later in FIG. 3, is inserted into an ink outlet 243 made of a rubber material, and the ink is supplied to the apparatus main body 101. The ink bag 241 is formed from a packaging material such as an airtight aluminum laminate film. As shown in FIG. 2, this ink bag 241 is typically housed in a plastic cartridge case 244 and is designed to be detachably attached to various inkjet printing apparatuses. The ink cartridge 201 used in the present invention is particularly preferably one that contains the ink used in the present invention and is detachably attachable to various inkjet printing apparatuses.

[0048] <Image forming method> The image forming method of this embodiment includes an ink ejection step in which a stimulus is applied to ink and the ink is ejected onto a recording medium to form an image. In order to improve image quality, such as image density, strike-through, and bleeding, the method may also include a step of applying a treatment liquid either before or after the ink is applied to the recording medium, or both.

[0049] -Ink ejection process and ink ejection means- The ink ejection step is a step of applying a stimulus (energy) to the ink to eject the ink and form an image on a recording medium. The ink ejection unit is a unit that applies a stimulus (energy) to the ink to eject the ink and form an image on a recording medium. The ink ejection unit is not particularly limited, and examples thereof include an inkjet head for ejecting ink.

[0050] In the present invention, it is preferable that at least a part of the liquid chamber, the fluid resistance portion, the diaphragm, and the nozzle member of the ink jet head is formed from a material containing at least one of silicon and nickel. The nozzle diameter of the inkjet nozzle is preferably 30 μm or less, and more preferably 1 μm or more and 20 μm or less.

[0051] The stimulus (energy) can be generated, for example, by the stimulus generating means. The stimulus is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include heat (temperature), pressure, vibration, and light. These may be used alone or in combination of two or more. Among these, heat and pressure are preferred. Examples of the stimulus generating means include a heating device, a pressure applying device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a light, and more specifically, examples thereof include a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by film boiling of a liquid using an electrothermal conversion element such as a heating resistor, a shape memory alloy actuator that uses a metal phase change caused by a temperature change, and an electrostatic actuator that uses electrostatic force.

[0052] The manner in which the ink is ejected is not particularly limited and varies depending on the type of stimulus, and examples thereof include a method in which, when the stimulus is "heat," thermal energy corresponding to a recording signal is applied to the ink in the recording head using, for example, a thermal head, the thermal energy generates bubbles in the ink, and the pressure of the bubbles causes the ink to be ejected as droplets from the nozzle holes of the recording head. Also, when the stimulus is "pressure," examples thereof include a method in which, when a voltage is applied 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, the volume of the pressure chamber decreases, and the ink is ejected as droplets from the nozzle holes of the recording head.

[0053] The size of the ink droplets to be ejected is, for example, 3×10 -15 ~40×10 -15 m 3 The volume is preferably (3 to 40 pL), the ejection speed is preferably 5 to 20 m / s, the drive frequency is preferably 1 kHz or higher, and the resolution is preferably 300 dpi or higher. The control means is not particularly limited as long as it can control the movement of each of the means, and can be appropriately selected depending on the purpose. For example, devices such as a sequencer and a computer can be mentioned.

[0054] Here, one embodiment of the inkjet printing method of the present invention using a serial inkjet printing device will be described with reference to the drawings. The inkjet printing device shown in Figure 3 has a device main body 101, a paper feed tray 102 for loading paper into the device main body 101, a paper output tray 103 for storing paper loaded into the device main body 101 and on which an image has been formed (recorded), and an ink cartridge loading unit 104. An operation unit 105 including operation keys and a display is arranged on the top surface of the ink cartridge loading unit 104. The ink cartridge loading unit 104 has an openable front cover 115 for installing and removing an ink cartridge 201.

[0055] As shown in FIGS. 4 and 5, within the device main body 101, a carriage 133 is held slidably in the main scanning direction by a guide rod 131 and a stay 132, which are guide members hung horizontally on left and right side plates (not shown), and is moved and scanned in the direction indicated by the arrow in FIG. 5 by a main scanning motor. The carriage 133 is fitted with a recording head 134 consisting of four inkjet recording heads that eject ink droplets of each color: yellow (Y), cyan (C), magenta (M), and black (Bk). The recording head 134 has multiple ink ejection ports arranged in a direction that intersects with the main scanning direction, and the ink droplet ejection direction faces downward. The inkjet recording head constituting the recording head 134 may be provided with an energy generating means for ejecting ink, such as a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses an electrothermal conversion element such as a heating resistor to utilize a phase change caused by film boiling of a liquid, a shape memory alloy actuator that uses a metal phase change caused by a temperature change, or an electrostatic actuator that uses electrostatic force. The carriage 133 also carries sub-tanks 135 of each color for supplying ink of each color to the recording head 134. The sub-tanks 135 are replenished with the ink of the present invention from the ink cartridges 201 used in the present invention loaded in the ink cartridge loading section 104 via ink supply tubes (not shown). The filters used in the present invention may be attached to the sub-tanks or the ink supply tubes.

[0056] On the other hand, as a paper feed section for feeding the paper 142 loaded on the paper loading section (pressure plate) 141 of the paper feed tray 102, it is provided with a crescent roller (paper feed roller 143) that separates and feeds the paper 142 one sheet at a time from the paper loading section 141, and a separation pad 144 that faces the paper feed roller 143 and is made of a material with a large friction coefficient, and this separation pad 144 is urged toward the paper feed roller 143. The conveying section for conveying the paper 142 fed from this paper feed section below the recording head 134 includes a conveying belt 151 for electrostatically attracting and conveying the paper 142, a counter roller 152 for sandwiching and conveying the paper 142 fed from the paper feed section via a guide 145 between the conveying belt 151, a conveying guide 153 for turning the paper 142 fed almost vertically upward by approximately 90 degrees so that it follows the conveying belt 151, and a leading edge pressure roller 155 urged toward the conveying belt 151 by a pressing member 154. Also provided is a charging roller 156 which is a charging means for charging the surface of the conveying belt 151.

[0057] The conveyor belt 151 is an endless belt that is stretched between a conveyor roller 157 and a tension roller 158 and can rotate in the belt conveyance direction. The conveyor belt 151 has a surface layer that serves as a paper attraction surface and is formed, for example, of a resin material with a thickness of approximately 40 μm that is not resistance-controlled, such as a copolymer of tetrafluoroethylene and ethylene (ETFE), and a back layer (medium-resistance layer, earth layer) made of the same material as the surface layer but with resistance control using carbon. A guide member 161 is disposed on the back side of the conveyor belt 151 in correspondence with the printing area of ​​the recording head 134. A paper discharge section for discharging the paper 142 recorded by the recording head 134 includes a separation claw 171 for separating the paper 142 from the conveyor belt 151, a paper discharge roller 172, and a paper discharge roller 173. A paper discharge tray 103 is disposed below the paper discharge roller 172.

[0058] A duplex paper feed unit 181 is detachably mounted on the rear surface of the apparatus main body 101. The duplex paper feed unit 181 takes in paper 142 returned by the reverse rotation of the conveyor belt 151, turns it over, and feeds it again between the counter roller 152 and the conveyor belt 151. A manual paper feed unit 182 is provided on the top surface of the duplex paper feed unit 181.

[0059] In this inkjet printing device, paper sheets 142 are separated and fed one by one from a paper feed unit, and the paper sheets 142 fed approximately vertically upward are guided by guide 145 and conveyed while being sandwiched between conveyor belt 151 and counter roller 152. Furthermore, the leading edge of the paper is guided by conveyor guide 153 and pressed against conveyor belt 151 by leading edge pressure roller 155, and the conveying direction is changed by approximately 90°. At this time, the conveyor belt 157 is charged by the charging roller 156, and the paper 142 is electrostatically attracted to the conveyor belt 151 and conveyed. Then, by driving the recording head 134 in accordance with an image signal while moving the carriage 133, ink droplets are ejected onto the stopped paper 142 to record one line, and after conveying the paper 142 a predetermined distance, the next line is recorded. Upon receiving a recording end signal or a signal indicating that the rear 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 it is detected that the remaining amount of ink in the sub-tank 135 is near the end, the required amount of ink is replenished from the ink cartridge 201 to the sub-tank 135 .

[0060] In this inkjet printing device, when the ink in the ink cartridge 201 used in the present invention runs out, the housing of the ink cartridge 201 can be disassembled and only the ink bag 241 inside can be replaced. Furthermore, the ink cartridge 201 can provide a stable supply of ink even when installed vertically and in a front-loading configuration. Therefore, even when the device main body 101 is installed with the space above it blocked, such as when it is stored in a rack, or when there is something placed on top of the device main body 101, the ink cartridge 201 can be easily replaced.

[0061] Although the present invention has been described as being applied to a serial (shuttle) inkjet printing device in which a carriage scans, it can also be applied to a line inkjet printing device equipped with a line head.

[0062] Furthermore, the inkjet printing apparatus and inkjet printing method of the present invention can be applied to various types of recording using inkjet recording methods, and are particularly suitable for use in, for example, inkjet recording printers, facsimile machines, copying machines, and printer / fax / copier combination machines.

[0063] -Ink recordings- The recorded matter recorded by the inkjet printing apparatus and inkjet printing method of the present invention is the ink recorded matter used in the present invention. The ink recording used in the present invention has an image formed on a recording medium using the ink used in the present invention. The recording medium is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include plain paper, glossy paper, general-purpose printing paper, etc. These may be used alone or in combination of two or more. The ink recording material has high image quality, is free from bleeding, and has excellent stability over time, and can be suitably used for various purposes such as documents on which various prints or images are recorded. [Example]

[0064] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

[0065] (Pigment Dispersion Liquid Preparation Example 1) <Preparation of Pigment-Containing Polymer Microparticle Dispersion> - Preparation of polymer solution A - A 1-L flask equipped with a mechanical stirrer, a thermometer, a nitrogen gas inlet tube, a reflux condenser, and a dropping funnel was thoroughly purged with nitrogen gas, and then 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, a mixed solution of 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 azobismethylvaleronitrile, and 18 g of methyl ethyl ketone was added dropwise to the flask over 2.5 hours. After the dropwise addition, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was added dropwise to the flask over 0.5 hours. After aging at 65 °C for 1 hour, 0.8 g of azobismethylvaleronitrile was added, and the mixture was further aged for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask, yielding 800 g of polymer solution A with a concentration of 50% by mass.

[0066] - Preparation of pigment-containing polymer particle dispersion - 28 g of polymer solution A, 42 g of carbon black (FW100, manufactured by Degussa), 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 thoroughly stirred and then kneaded using a roll mill. The resulting paste was added to 200 g of pure water and thoroughly stirred. After that, the methyl ethyl ketone and water were distilled off using an evaporator. Furthermore, to remove coarse particles, the resulting dispersion was pressure-filtered through a polyvinylidene fluoride membrane filter with an average pore size of 5.0 μm, yielding a black pigment-containing polymer microparticle dispersion containing 15% pigment by weight and 20% solids by weight. The average particle diameter (D 50 The average particle diameter (D 50 ) was measured using a particle size distribution measuring device (Nanotrac UPA-EX150, manufactured by Nikkiso Co., Ltd.).

[0067] (Silicone emulsion preparation example 1) To prepare the silicone emulsion, a mixture of 381.2 g of a hydroxyl-endblocked polydimethylsiloxane fluid with a degree of polymerization of approximately 35, 3.85 g of trimethylsiloxy-endblocked polymethylhydrogensiloxane with a viscosity of approximately 0.13 Pa·s at 25°C and a silicon-bonded hydrogen content of approximately 1.6% by weight, 15.9 g of a 30% solution of sodium lauryl sulfate, and 186 g of distilled water was prepared. This mixture was homogenized twice in a single-stage laboratory homogenizer to produce a uniform emulsion with an average particle size of approximately 1.1 μm. 3.2 g of dodecylbenzenesulfonic acid was added to the emulsion, which was then allowed to polymerize for 24 hours at approximately 25°C. The polymerization was then terminated by adding enough diethylamine to raise the pH to 7-7.5. Silicone Emulsion 1 was obtained using the above procedure. The average particle size of the resulting silicone emulsion was 4.6 μm.

[0068] (Silicone emulsion preparation examples 2-3) Silicone Emulsions 2 and 3, which are polydimethylsiloxane emulsions with different average particle sizes, were obtained in the same manner as in Silicone Emulsion Preparation Example 1, except that the shear force of the homogenizer was adjusted as needed. The resulting silicone emulsion 2 had an average particle size of 196 nm, and the silicone emulsion 3 had an average particle size of 6.0 μm.

[0069] (Manufacturing Examples 1 to 15) <Preparation of inkjet ink> Each inkjet ink was prepared according to the following procedure. First, the water-soluble organic solvent (wetting agent), penetrant, surfactant, anti-fungal agent, and water shown in Tables 1 and 2 below were mixed and stirred for 1 hour to achieve a uniform mixture. Depending on the mixture, a water-dispersible resin was added and stirred for 1 hour, and then a pigment-containing polymer particle dispersion, antifoaming agent, and pH adjuster were added and stirred for 1 hour. The resulting dispersion was pressure-filtered using a polyvinylidene fluoride membrane filter with an average pore size of 5.0 μm to remove coarse particles and dust, thereby preparing each of the inkjet inks of Production Examples 1 to 15. The contents of the pigment dispersion and resin dispersion in Tables 1 and 2 indicate the solid content, and the unit of the content of each component is parts by mass.

[0070] [Table 1]

[0071] [Table 2]

[0072] The abbreviations in Tables 1 and 2 above have the following meanings. *Pigment dispersion (prepared as described above) *Polyurethane emulsion: Sanyo Chemical Industries, Ltd., U-coat UA-3945, solid content 38.4% by mass, average particle size 35 nm *2,5,8,11-tetramethyl-6-dodecyne-5,8-diol: acetylene compound *2,4,7,9-tetramethyl-5-decyne-4,7-diol: acetylene compound *SAG008: Polyether-modified silicone surfactant (manufactured by Nissin Chemical Industry Co., Ltd., active ingredient 95% or more by weight) *DSN403N: Fluorine-based surfactant (manufactured by Daikin Industries, Ltd., active ingredient 98% or more by mass) *Softanol EP-7025: Polyoxyalkylene alkyl ether (manufactured by Nippon Shokubai Co., Ltd., 100% by weight)

[0073] Next, a number of filters were prepared with different pore sizes, shapes, thicknesses, materials, and processing methods as shown in Table 3.

[0074] [Table 3]

[0075] (Examples 1 to 17 and Comparative Examples 1 to 7) Next, an inkjet printer (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) was filled with each ink shown in Tables 1 and 2 and equipped with each filter shown in Table 3, and various properties were evaluated as follows. The filters in the inkjet printers used in the examples and comparative examples were installed immediately before the head (between the head and the supply path of the subtank). The results are shown in Tables 4 and 5.

[0076] <Initial filling properties> Under environmental conditions adjusted to 23±0.5°C and 50±5% RH, an inkjet printing device (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) was filled with a 10% propylene glycol aqueous solution, and then filled with the inks of Production Examples 1 to 15. A nozzle check pattern was printed, and the number of times nozzle cleaning was performed until there were no more non-ejecting nozzles was determined. Evaluation was based on the following criteria. [Evaluation criteria] A: It will recover after 1-2 cleanings. B: Recovers after 3 to 10 cleanings A rating of A is a practical level.

[0077] <Foam inside the cap> Under environmental conditions adjusted to 23±0.5°C and 50±5% RH, an inkjet printer (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) was used to fill the inks of Production Examples 1 to 15, and then ink refresh was performed five times. The inside of the cap was visually observed when the head was sucked, and the ink was evaluated according to the following criteria. A grade of C or higher was considered to be practically acceptable. [Evaluation criteria] A: No bubbles in the cap B: There is foam only at the bottom of the cap, but the area of ​​the foam is less than 10% of the area of ​​the bottom of the cap. C: There is foam only at the bottom of the cap, but the area of ​​the foam is more than 10% of the area of ​​the bottom of the cap. D: There are bubbles all over the cap

[0078] <Discharge stability> Under environmental conditions adjusted to 32±0.5°C and 20±5% RH, an inkjet printer (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) was used to fill the inks of Production Examples 1 to 15, and then left for 6 hours with the cap open. After leaving the inks, nozzle cleaning was performed once, and the ejection performance was evaluated according to the following criteria. A grade of B or higher is considered to be at a practical level. [Evaluation criteria] A: No non-discharge B: Non-ejection occurs, non-ejection recovered within three nozzle cleanings C: Non-ejection occurred, non-ejection recovered after 3 nozzle cleanings and 1 nozzle refresh

[0079] <Liquid permeability> Under environmental conditions adjusted to 23±0.5°C and 50±5% RH, an inkjet printing device (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) was used to fill the ink, and 5 kg of the inks of Production Examples 1 to 15 were passed through. The ink ejection properties were evaluated according to the following criteria. A grade of C or higher is considered to be practically acceptable. [Evaluation criteria] A: No non-discharge B: Non-ejection occurs, non-ejection recovered within one nozzle cleaning C: Non-ejection occurs, non-ejection recovered within three nozzle cleanings D: Ink cannot be ejected

[0080] [Table 4]

[0081] [Table 5] [Industrial Applicability]

[0082] The inkjet printing apparatus and inkjet printing method of the present invention can be applied to various types of recording using an inkjet recording system, and are particularly suitable for use in, for example, inkjet recording printers, facsimile machines, copying machines, and printer / fax / copier combination machines. [Explanation of symbols]

[0083] 101 Device body 102 Paper tray 103 Paper output tray 104 Ink cartridge loading section 111 Upper cover 112 Front 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Subtank 141 Paper stacking section 142 Paper 144 Separation Pad 151 Conveyor belt 152 Counter roller again 156 Charging roller 157 Conveyor roller 158 Tension roller 171 Separation claw 172 Paper ejection roller 173 Paper ejection roller 181 Duplex paper feed unit 201 Ink cartridges 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge Case [Prior art documents] [Patent documents]

[0084] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-223980

Claims

1. An inkjet printing device having ink, an inkjet head, an ink container, and a filter provided in an ink supply path, the ink contains water, an acetylene compound, an alkylene glycol ether, and an organic solvent; the organic solvent contains 1,2-propanediol and glycerin, The filter has pores, and the pores have a pore size of 5 μm or more and 20 μm or less, The thickness of the filter is 0.1 mm or more and 0.5 mm or less, An inkjet printing apparatus, wherein the ink contains a silicone emulsion.

2. The inkjet printing apparatus according to claim 1 , wherein the pore diameter is 10 μm or more and 20 μm or less.

3. The inkjet printing device according to claim 1 or 2, wherein the pores have a structure of stacked fibers.

4. 4. The inkjet printing apparatus according to claim 1, wherein the filter is a sintered body of stainless steel.

5. The inkjet printing apparatus according to claim 1 or 2, wherein the filter has a plate-like shape.

6. The inkjet printing apparatus according to claim 5 , wherein the filter has a plurality of holes penetrating from one surface to the other surface.

7. 7. The inkjet printing apparatus according to claim 6, wherein the one surface is a surface on the upstream side in the ink supply direction, and the other surface is a surface on the downstream side in the ink supply direction.

8. 8. The inkjet printing apparatus according to claim 1, wherein the content of the organic solvent is 35% by mass or more and 50% by mass or less with respect to the total amount of the ink.

9. 9. The inkjet printing apparatus according to claim 1, wherein the acetylene compound has 16 carbon atoms.

10. An inkjet printing method, comprising using the inkjet printing apparatus according to any one of claims 1 to 9.

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