Cleaning liquid for inkjet recording devices

Abstract

A cleaning liquid for inkjet recording devices according to the present invention contains a polyhydric alcohol, a glycol ether and water; the content ratio of the polyhydric alcohol to the glycol ether is 3 or more; the content of the water in the cleaning liquid is 65% by mass or more relative to 100% by mass of the cleaning liquid; and the surface tension of the cleaning liquid is 30 mN / m to 45 mN / m.

Description

Cleaning liquid for inkjet recording devices

[0001] The present invention relates to a cleaning liquid for an inkjet recording apparatus.

[0002] Inkjet recording devices perform recording by ejecting ink droplets from a large number of nozzles formed in an inkjet head toward a recording medium and allowing the ink to fix on the recording medium, but if the ink hardens inside the device due to moisture evaporation or the like, the nozzle surface of the inkjet head and ink lines such as in-line filters become clogged, resulting in ink not being ejected. The nozzle surface of the nozzle head to which ink has adhered is cleaned, for example, by applying a cleaning liquid and then wiping.

[0003] In Patent Document 1, the SP value is 26 MPa. １／２ The above water-soluble organic solvents and SP value 24 MPa １／２ The document describes a maintenance liquid (cleaning liquid) for inkjet recording that contains the following water-soluble organic solvent and water in specified amounts. In the examples, after ink ejection, the maintenance liquid loaded in the inkjet printer is applied to the nozzle surface of the inkjet head with a roller, and then the nozzle surface of the inkjet head is wiped with a wiper blade (hydrogenated NBR) to confirm cleanability.

[0004] Patent Document 2 describes a cleaning liquid used for cleaning inkjet recording devices, which contains a nonionic surfactant having a solubility in water at 20°C of less than 0.2% by mass, a first water-soluble organic solvent having a solubility parameter (SP value) of 13 or more, a second water-soluble organic solvent having a solubility parameter (SP value) of less than 12, and water, and which satisfies a specific relationship. In the examples, the cleaning liquids of the examples and comparative examples, after evaporating 30% or so, are brought into contact with aqueous ink, and the contact interface is visually observed to confirm cleaning properties based on the presence or absence of aggregates at the contact interface.

[0005] Patent Document 3 describes an ink set for inkjet recording, which includes an aqueous ink and an aqueous cleaning solution, the aqueous cleaning solution containing a nonionic surfactant, the nonionic surfactant having an amino group in its molecule, and the surface tension of the aqueous ink and the surface tension of the aqueous cleaning solution satisfying a predetermined relationship (A). In the examples, after a printing durability test conducted under conditions of a temperature of 25°C and a humidity of 60% RH and a conveying speed of 350 mm / sec, an aqueous cleaning solution of the example or comparative example is supplied to the nozzle surface, and then a purging operation and a wiping operation are performed, and cleaning performance is confirmed based on the presence or absence of ink stains on the nozzle surface.

[0006] On the other hand, one method for recovering ink lines, such as inkjet head nozzles and in-line filters, contaminated with solidified ink involves filling and supplying a cleaning liquid into the nozzles. Patent Document 4 describes a filling liquid for inkjet printheads, which contains a specific amount of an alkylene oxide adduct exhibiting a specific HLB, a specific amount of a humectant, and water, and has a specific viscosity and pH. In the examples, a recording head filled with an aqueous inkjet ink composition (pigment concentration 12% by mass, pigment / alkali-soluble resin (mass) = 10 / 4) was left in an oven at 50°C for three months. The recording head, which had experienced ink ejection problems, was filled with cleaning liquids (pH 9 to 13) of the examples and comparative examples in an initial filling mode, and the cleaning ability was confirmed by the improvement in ejection problems.

[0007] There has been a demand for cleaners with superior cleaning power for use in inkjet recording devices.

[0008] JP 2013-10267 A JP 2020-196781 A JP 2018-119078 A JP 2018-1510 A

[0009] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cleaning liquid for an ink jet recording apparatus that has excellent cleaning power.

[0010] As a result of extensive research into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a cleaning liquid for an inkjet recording device that contains polyhydric alcohols, glycol ethers, and water, wherein the glycol ethers and the polyhydric alcohols are contained in a specific content ratio, the water is contained in a specific content, and the cleaning liquid has a specific surface tension, and have thereby completed the present invention.

[0011] That is, the cleaning liquid for an inkjet recording device of the present invention is a cleaning liquid for an inkjet recording device containing polyhydric alcohols, glycol ethers, and water, wherein the content ratio (mass ratio) of the polyhydric alcohols to the glycol ethers is 3 or more, the content of water contained in the cleaning liquid is 65 mass % or more relative to 100 mass % of the cleaning liquid, and the surface tension of the cleaning liquid is 30 mN / m or more and 45 mN / m or less.

[0012] According to the present invention, it is possible to provide a cleaning liquid for an ink jet recording apparatus that has excellent cleaning power.

[0013] The cleaning liquid for an inkjet recording device of the present invention (hereinafter sometimes simply referred to as the cleaning liquid) contains polyhydric alcohols, glycol ethers, and water, wherein the ratio (mass ratio) of the polyhydric alcohols to the glycol ethers is 3 or more, the content of water in the cleaning liquid is 65% by mass or more, based on 100% by mass of the cleaning liquid, and the surface tension of the cleaning liquid is 30 mN / m or more and 45 mN / m or less. The cleaning liquid of the present invention has excellent cleaning power, as (1) the content (mass ratio) of the polyhydric alcohols to the glycol ethers is 3 or more, (2) the content of water in the cleaning liquid is 65% by mass or more, based on 100% by mass of the cleaning liquid, and (3) the surface tension of the cleaning liquid is 30 mN / m or more and 45 mN / m or less. The cleaning liquid of the present invention preferably has excellent cleaning power for ink lines, such as inkjet head nozzles and in-line filters, that are contaminated with solidified ink. The cleaning liquid of the present invention can be suitably used as a cleaning liquid for inkjet recording devices that use inks containing a large amount of binder components (e.g., 5% by mass or more), such as inks for inkjet textile printing (textile printing inks). Furthermore, the cleaning liquid of the present invention has high detergency and is therefore excellent in safety because it is composed mainly of polyhydric alcohols, glycol ethers, and water.

[0014] Among the polyhydric alcohols contained in the cleaning solution of the present invention, dihydric alcohols or trihydric alcohols are preferred. Among the dihydric alcohols, glycols are preferred. Among the glycols, aliphatic chain diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-butanediol, 2-methyl-1,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, and 1,6-hexanediol are preferred; and aliphatic cyclic diols such as 1,2-cyclohexanediol and 1,4-cyclohexanediol are more preferred, with aliphatic chain diols being more preferred. Among these, diethylene glycol, triethylene glycol, and propylene glycol are even more preferred. Among the trihydric alcohols, glycerin is preferred. Among the polyhydric alcohols, diethylene glycol, triethylene glycol, propylene glycol, and glycerin are preferred. The polyhydric alcohols may be used alone or in combination of two or more. By including the polyhydric alcohols, the cleaning liquid can be endowed with moisture retention (ability to prevent drying).

[0015] The content of the polyhydric alcohol in the cleaning solution is preferably 0.5% by mass to 30% by mass, more preferably 5% by mass to 27% by mass, based on 100% by mass of the cleaning solution. When two or more polyhydric alcohols are used, the content is the total amount of the polyhydric alcohols.

[0016] The glycol ethers contained in the cleaning solution of the present invention are preferably glycol alkyl ethers, and among these, glycol monoalkyl ethers, glycol dialkyl ethers, and glycol monoalkyl ether monoacetates are preferred, with glycol monoalkyl ethers and glycol dialkyl ethers being more preferred, and glycol monoalkyl ethers being particularly preferred. The alkyl chain in the glycol alkyl ethers (glycol monoalkyl ethers, glycol dialkyl ethers, and glycol monoalkyl acetates) is preferably an alkyl chain having 1 to 8 carbon atoms, and more preferably an alkyl chain having 1 or 4 to 6 carbon atoms. The glycol monoalkyl ethers are preferably ethylene glycol ether-based compounds such as ethylene glycol ethers, diethylene glycol ethers, and triethylene glycol ethers; or propylene glycol ether-based compounds such as propylene glycol ethers, dipropylene glycol ethers, and tripropylene glycol ethers, with propylene glycol ether-based compounds being more preferred. Among the ethylene glycol ether-based compounds, diethylene glycol ethers and triethylene glycol ethers are preferred, with diethylene glycol monobutyl ether and triethylene glycol monobutyl ether being particularly preferred. Among the above propylene glycol ether compounds, dipropylene glycol ethers and tripropylene glycol ethers are preferred, and dipropylene glycol monomethyl ether and tripropylene glycol monomethyl ether are particularly preferred. The glycol ethers may be used alone or in combination of two or more. By including the glycol ethers, the cleaning solution can be imparted with the ability to penetrate ink-adhering components (pigments, binders).

[0017] The content of glycol ethers in the cleaning solution is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 0.7% by mass or more and 5% by mass or less, relative to 100% by mass of the cleaning solution. When two or more glycol ethers are used, the content is the total amount of the glycol ethers.

[0018] The content ratio (mass ratio) of the polyhydric alcohols to the glycol ethers is 3 or more, preferably 4.5 or more, and more preferably 6 or more. By adjusting the content ratio in this manner, a cleaning liquid with high detergency can be obtained. For the same reason, the upper limit of the content ratio is preferably 30 or less, more preferably 20 or less, and even more preferably 15 or less.

[0019] The cleaning solution of the present invention contains water in an amount of 65% by mass or more, preferably 68% by mass or more and 95% by mass or less, and more preferably 70% by mass or more and 90% by mass or less, based on 100% by mass of the cleaning solution. By setting the water content within this range, the cleaning solution can have high detergency.

[0020] The surface tension of the cleaning liquid is 30 mN / m or more and 45 mN / m or less, and preferably 30 mN / m or more and 40 mN / m or less. By setting the surface tension of the cleaning liquid in this range, the cleaning power of the cleaning liquid can be increased.

[0021] The cleaning solution preferably further contains a basic compound. By including a basic compound, the cleaning power of the cleaning solution can be improved. As the basic compound, inorganic basic compounds and organic basic compounds can be used. Among these, inorganic basic compounds are preferred. As the organic basic compound, ammonia, alkanolamines, alkylamines, etc. are preferred. Among these, ammonia, triethylamine, N,N,-dimethylaminoethanol, N,N-dibutylaminoethanol, N-methyl-diethanolamine, 2-amino-2-methylpropanol, diethanolamine, triethanolamine, N-methylaminoethanol, and N,N-diethylaminoethanol are preferred. As the inorganic basic compound, hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, carbonates such as potassium carbonate and sodium carbonate, and bicarbonates such as potassium hydrogen carbonate and sodium hydrogen carbonate (baking soda) are preferred. Among these, bicarbonates are preferred, and sodium hydrogen carbonate (baking soda) is more preferred. The content of the basic compound is preferably 0.01% by mass or more and 0.5% by mass or less, more preferably 0.05% by mass or more and 0.3% by mass or less, based on 100% by mass of the cleaning solution. By setting the content of sodium bicarbonate within this range, the detergency of the cleaning solution can be improved.

[0022] The cleaning liquid preferably further contains a surfactant. By containing a surfactant, the cleaning power of the cleaning liquid can be improved. The content of the surfactant is preferably 0.01% by mass or more and 0.5% by mass or less, more preferably 0.05% by mass or more and 0.3% by mass or less, relative to 100% by mass of the cleaning liquid. By setting the content of the surfactant within this range, the cleaning power of the cleaning liquid can be improved.

[0023] Examples of the surfactant include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, polymer surfactants, etc. These surfactants may be used alone or in combination of two or more. The surfactant is preferably an anionic surfactant or a nonionic surfactant, and more preferably a nonionic surfactant.

[0024] Examples of anionic surfactants include alkyl sulfate salts such as ammonium dodecyl sulfate and sodium dodecyl sulfate; alkyl sulfonate salts such as ammonium dodecyl sulfonate, sodium dodecyl sulfonate and sodium alkyl diphenyl ether disulfonate; alkyl aryl sulfonate salts such as ammonium dodecyl benzene sulfonate and sodium dodecyl naphthalene sulfonate; polyoxyethylene alkyl sulfonate salts; polyoxyethylene alkyl sulfate salts; polyoxyethylene alkyl aryl sulfate salts; dialkyl sulfosuccinate salts; and aryl sulfonic acid-formalin condensates. fatty acid salts such as ammonium laurate and sodium stearylate; sulfates or salts thereof having an allyl group such as bis(polyoxyethylene polycyclic phenyl ether) methacrylate sulfonate salts, propenyl-alkyl sulfosuccinate ester salts, (meth)acrylic acid polyoxyethylene sulfonate salts, (meth)acrylic acid polyoxyethylene phosphonate salts, and sulfonate salts of allyloxymethyl alkyloxy polyoxyethylene; sulfate salts of allyloxymethyl alkoxyethyl polyoxyethylene, and polyoxyalkylene alkenyl ether ammonium sulfate salts, but are not limited to these examples.

[0025] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, condensates of polyethylene glycol and polypropylene glycol, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid monoglycerides, condensation products of ethylene oxide and aliphatic amines, allyloxymethylalkoxyethylhydroxypolyoxyethylene, polyoxyalkylene alkenyl ethers, acetylene glycols, and acetylene alcohols, but are not limited to these examples. Examples of nonionic surfactants that can be used include commercially available products. Examples of commercially available products include "EMULGEN (registered trademark) 108" (polyoxyethylene lauryl ether) manufactured by Kao Corporation, "OLFIN (registered trademark) E1004" (acetylene glycol-based) manufactured by Nissin Chemical Industry Co., Ltd., and "NONION EH-204" (polyoxyethylene-2-ethylhexyl ether) manufactured by NOF Corporation.

[0026] Examples of cationic surfactants include alkyl ammonium salts such as dodecyl ammonium chloride, but the present invention is not limited to these examples.

[0027] Examples of amphoteric surfactants include, but are not limited to, betaine ester surfactants.

[0028] Examples of polymer surfactants include poly(meth)acrylates such as sodium polyacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polyhydroxyalkyl(meth)acrylates such as polyhydroxyethyl acrylate; and copolymers containing one or more of the monomers constituting these polymers as copolymerization components, but are not limited to these examples.

[0029] The cleaning solution of the present invention may further contain an acid or a salt of the acid. The inclusion of an acid or a salt of the acid tends to enhance the dispersibility of the pigment components contained in the ink. Preferred examples of the acid include poly(meth)acrylic acid and aliphatic carboxylic acids. Preferred examples of the aliphatic carboxylic acids include tricarboxylic acids such as tricarballylic acid, dicarboxylic acids such as succinic acid, and monocarboxylic acids such as acetic acid and formic acid. Preferred examples of the salts include alkali metal salts of the acids, with sodium salts being more preferred. Examples include sodium polyacrylate, sodium tricarballylate, sodium succinate, sodium acetate, and sodium formate. While there are no particular limitations on the content of the acid or the content of the acid salt, the total content of the acid and the acid salt is preferably 0.0001% by mass or more and 0.3% by mass or less relative to 100% by mass of the cleaning solution.

[0030] The cleaning solution of the present invention may further contain a preservative. Conventionally known preservatives can be used as the preservative, and preferred examples include isothiazolinone preservatives such as methylisothiazolinone, carbamates such as butylcarbamate iodopropynyl, pyrithiones such as sodium pyrithione, and benzimidazoles such as thiabendazole. The content of the preservative is not particularly limited, but is preferably 0.0001% by mass or more and 0.3% by mass or less relative to 100% by mass of the cleaning solution.

[0031] The cleaning liquid for an inkjet recording device of the present invention can provide a cleaning liquid for an inkjet recording device with excellent cleaning power. The cleaning liquid for an inkjet recording device of the present invention is also suitable as a cleaning liquid for an inkjet recording device using, for example, inkjet ink (textile printing ink) for pigment textile printing. Inkjet ink for pigment textile printing is required to have high fastness, so it contains a large amount of binder component, and once the binder component adheres to the head, recovery is particularly difficult. The cleaning liquid for an inkjet recording device of the present invention has excellent cleaning power even for these inks.

[0032] The cleaning liquid for an inkjet recording apparatus of the present invention exhibits excellent cleaning power for any ink, but is particularly suitable for use with textile printing inks, inks containing a large amount of binder components (for example, 5% by mass or more), or inks containing polyhydric alcohols, glycol ethers, and water.

[0033] The present disclosure also provides a method for cleaning an inkjet recording device using a composition containing a polyhydric alcohol, glycol ethers, and water, wherein the content (mass ratio) of the polyhydric alcohol to the glycol ethers is 3 or more, the content of water contained in the composition is 65 mass% or more relative to 100 mass% of the composition, and the composition has a surface tension of 30 mN / m or more and 45 mN / m or less. The method for cleaning an inkjet recording device can efficiently clean the supply lines and inkjet head nozzles of the inkjet recording device.

[0034] The above-described method for cleaning an inkjet recording apparatus is particularly suitable for cleaning an inkjet recording apparatus that uses a textile printing ink, an ink containing a large amount of a binder component (e.g., 5% by mass or more), or an ink containing a polyhydric alcohol, a glycol ether, and water.

[0035] Suitable aspects of the composition used in the method for cleaning an inkjet recording device (for example, the polyhydric alcohols, glycol ethers, content ratio thereof, water content ratio, surface tension, etc. of the composition) are each independently the same as the suitable aspects described above for the cleaning liquid for an inkjet recording device of the present invention (for example, the polyhydric alcohols, glycol ethers, content ratio thereof, water content ratio, surface tension, etc. of the cleaning liquid).

[0036] The method for cleaning the inkjet recording device is not particularly limited other than the use of the composition. Examples of the cleaning method include replacing the ink bottle used with a bottle filled with a predetermined amount of the composition and passing the composition through the ink supply line and inkjet head nozzles for a certain period of time. In this case, after the composition has passed through, the bottle is replaced with an ink bottle and check printing is performed to confirm the cleaning effect. Furthermore, in addition to replacing the ink bottle, a bottle filled with a predetermined amount of the composition may be installed in another location and the composition may be appropriately passed through the ink line. In this case, after the composition has passed through, the ink is passed through the ink supply line and inkjet head nozzles and check printing is performed to confirm the cleaning effect. The method for cleaning the inkjet recording device of the present disclosure enables sufficient cleaning effects to be obtained even when a small amount of composition is used for cleaning and / or the cleaning time is short.

[0037] The present disclosure also provides use of a composition containing polyhydric alcohols, glycol ethers, and water, wherein the content (mass ratio) of the polyhydric alcohols to the glycol ethers is 3 or more, the content of water in the composition is 65 mass% or more relative to 100 mass% of the composition, and the composition has a surface tension of 30 mN / m or more and 45 mN / m or less, as a cleaning liquid for an inkjet recording device. Use of the composition as a cleaning liquid for an inkjet recording device allows efficient cleaning of the supply lines and inkjet head nozzles of the inkjet recording device.

[0038] The use of the composition as a cleaning liquid for an inkjet recording device is particularly suitable for cleaning an inkjet recording device that uses a textile printing ink, an ink containing a large amount of a binder component (for example, 5% by mass or more), or an ink containing a polyhydric alcohol, a glycol ether, and water.

[0039] When the composition is used as a cleaning liquid for an inkjet recording device, suitable aspects of the composition (for example, the polyhydric alcohols, glycol ethers, content ratio thereof, water content ratio, surface tension, etc. in the composition) are each independently the same as the suitable aspects described above for the cleaning liquid for an inkjet recording device of the present invention (for example, the polyhydric alcohols, glycol ethers, content ratio thereof, water content ratio, surface tension, etc. in the cleaning liquid).

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass."

[0041] The measurement and evaluation methods are as follows: <Average particle size of resin emulsion particles> The resin emulsion was measured using a particle size distribution measuring device (manufactured by Otsuka Electronics Co., Ltd., product number: nanoSAQLA) using a dynamic light scattering method to determine the volumetric particle size distribution, and the average particle size obtained by cumulant analysis was used as the average particle size of the resin emulsion particles.

[0042] <Average Particle Diameter of Pigment> The pigment dispersion was measured using a particle size distribution measuring device (manufactured by Otsuka Electronics Co., Ltd., product number: nanoSAQLA) using a dynamic light scattering method to determine the volume-based particle size distribution, and the average particle diameter obtained by cumulant method analysis was defined as the average particle diameter of the pigment.

[0043] <Ink Viscosity> The following aqueous inks A to C were measured using an E-type viscometer TPE-100 (manufactured by Toki Sangyo Co., Ltd.) with a rotor R24, 0.8 degrees, and 25°C.

[0044] <pH of Cleaning Solution> The pH of each of the cleaning solutions of Examples 1 to 13 and Comparative Examples 1 to 5 was measured at 25° C. using a pH meter (G1500 manufactured by Gleisinger).

[0045] <Surface Tension of Cleaning Liquid> The surface tension of each of the cleaning liquids of Examples 1 to 13 and Comparative Examples 1 to 5 was measured at 25° C. according to the Wilhelmy method using a surface tensiometer DY-500 (manufactured by Kyowa Interface Science Co., Ltd.).

[0046] <Emulsion Production Examples> [Emulsion Production Example 1] 252 parts of deionized water was charged into a flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. A pre-emulsion for dropping was prepared by adding 437 parts of deionized water, 80 parts of a 25% aqueous solution of an emulsifier (manufactured by ADEKA Corporation, trade name: ADEKA REASORB SR-10), 25 parts of acrylic acid, 565 parts of 2-ethylhexyl acrylate, 50 parts of cyclohexyl methacrylate, 10 parts of hydroxyethyl methacrylate, and 350 parts of styrene to the dropping funnel. 44 parts of this pre-emulsion, corresponding to 3% of the total amount of all monomer components, was added to the flask. The temperature was raised to 80°C while slowly blowing in nitrogen gas, and 30 parts of a 5% aqueous ammonium persulfate solution was added to initiate polymerization. Thereafter, the remainder of the pre-emulsion for dropping and 30 parts of a 5% aqueous ammonium persulfate solution were uniformly added dropwise to the flask over 240 minutes. After the dropwise addition was completed, the contents of the flask were maintained at 80°C for 180 minutes, and the pH was adjusted to 8.5 and the solids content to 50% by adding 25% aqueous ammonia and deionized water, thereby terminating the polymerization. The resulting reaction solution was cooled to room temperature and then filtered through a 300-mesh wire mesh to obtain an emulsion (emulsion: acrylic). The solids content (resin emulsion particles) of this emulsion was 50%, the Tg was -21°C, and the average particle size of the resin emulsion particles was 200 nm.

[0047] <Pigment Dispersion Production Examples> [Pigment Dispersion Production Example 1] 5 parts of a dispersant, Discoat N-14 (manufactured by Dai-ichi Kogyo Seiyaku), 6 parts of propylene glycol, 70 parts of deionized water, 100 parts of titanium oxide, CR-95 (manufactured by Ishihara Sangyo Kaisha), and zirconia beads with a particle size of 0.5 mm were filled to a volume ratio of 50%, and dispersed using a bead mill to obtain a white pigment dispersion containing 55% pigment (pigment dispersion: titanium oxide). The average particle size of the pigment in the obtained white pigment dispersion was 330 nm.

[0048] [Pigment Dispersion Production Example 2] 3 parts of a dispersant, Joncryl 678 (manufactured by BASF), 1.3 parts of dimethylaminoethanol, and 81 parts of deionized water were mixed and stirred at 70°C. Next, 15 parts of a blue pigment, C.I. Pigment Blue 15:3 LIONOL BLUE FG-7330 (manufactured by Toyo Ink Co., Ltd.), 0.1 parts of a surfactant, Olfine D-10PG (manufactured by Nissin Chemical Industry Co., Ltd.), and zirconia beads with a particle size of 0.5 mm were added to a volumetric pack of 50%, dispersed using a bead mill, and filtered through a 1 μm pore size filter (MCP-1-C10S, manufactured by Advantec Co., Ltd.) to obtain a 15% blue pigment dispersion (pigment dispersion: cyan). The average particle size of the pigment in the resulting blue pigment dispersion was 90 nm.

[0049] <Water-Based Ink Production Examples> [Water-Based Ink A Production Example] 20 parts of the acrylic emulsion of Emulsion Production Example 1 (10 parts as resin emulsion particles), 25 parts of the pigment dispersion of Pigment Dispersion Production Example 1 (14 parts as pigment), 15 parts of triethylene glycol, 3.0 parts of diethylene glycol monobutyl ether, and 1.0 part of the surfactant Olfine E1004 (manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and filtered through a 1 μm pore size filter (MCP-1-C10S, manufactured by Advantec Co., Ltd.) to produce water-based ink A.

[0050] [Aqueous Ink B Production Example] A urethane resin emulsion (emulsion: urethane) was prepared by adding 17 parts (5 parts as resin emulsion particles) of Takelac W6010 (manufactured by Mitsui Chemicals, Inc., solids content 30%), 25 parts (14 parts as pigment) of the pigment dispersion from Pigment Dispersion Production Example 1, 15 parts of triethylene glycol, 3 parts of diethylene glycol monobutyl ether, and 1.0 part of the surfactant Olfine E1004 (manufactured by Shin-Etsu Chemical Co., Ltd.) and deionized water to a total volume of 100 parts. These ingredients were mixed and filtered through a 1 μm pore size filter (MCP-1-C10S, manufactured by Advantec Co., Ltd.), to produce aqueous ink B.

[0051] [Aqueous Ink C Production Example] 20 parts of the acrylic emulsion of Emulsion Production Example 1 (10 parts as resin emulsion particles), 23 parts of the pigment dispersion of Pigment Dispersion Production Example 2 (3.5 parts as pigment), 15 parts of triethylene glycol, 3.0 parts of diethylene glycol monobutyl ether, and 1.0 part of the surfactant Olfin E1004 (manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and filtered through a 1 μm pore size filter (MCP-1-C10S, manufactured by Advantec Co., Ltd.) to produce aqueous ink C. The formulation of the produced ink is shown in Table 1.

[0052]

[0053] Example 1 (Production of cleaning solution) 20 parts of triethylene glycol, 3 parts of diethylene glycol monobutyl ether, 0.1 parts of a surfactant, Olfine E1004 (manufactured by Shin-Etsu Chemical Co., Ltd.), and 76.9 parts of deionized water were mixed and filtered through a 1 μm pore size filter (MCP-1-C10S, manufactured by Advantec Co., Ltd.), to produce a cleaning solution (1).

[0054] [Examples 2 to 13 and Comparative Examples 1 to 5] Cleaning solutions (2) to (13) according to Examples 2 to 13 and cleaning solutions (c1) to (c5) according to Comparative Examples 1 to 5 were produced in the same manner as in Example 1 (production of cleaning solution), except that the type and amount of each raw material used were changed as shown in Tables 2 to 4, and the amount of deionized water used was adjusted so that the total amount was 100 parts. The head nozzle recovery properties of the cleaning solutions produced in each Example and Comparative Example were evaluated according to the following evaluation criteria. The results are shown in Tables 2 to 4.

[0055] <Evaluation of Improvement of Ejection Defects> Water-based ink A was filled into a Mastermind MMP-TX13 textile printer, and three 120 mm x 120 mm solid prints were performed consecutively on cotton fabric (a 100% cotton white T-shirt manufactured by Hanes) at 1440 dpi x 1440 dpi, a print speed setting of 8, and on three consecutive sheets. This confirmed that the ink had been filled. The inkjet head was then left uncapped for one week in an environment with a temperature of 23°C and humidity of 50%. By leaving the ink uncapped, the ink dried and firmly adhered. After leaving the ink uncapped, a nozzle check print was performed (all 180 nozzles were ejected in sequence to print ruled lines). More than 10 nozzles were confirmed to have exhibited ink scattering (curvature) and missing dots due to poor ink ejection.

[0056] A print head that had experienced ink ejection problems was cleaned by filling it with the cleaning solution of each of Examples 1 to 13 and Comparative Examples 1 to 5 for 10 minutes in the fill mode, and then refilled with water-based ink A and performed nozzle check printing, and the improvement of the ejection problems was evaluated according to the following evaluation criteria. A similar evaluation was also performed for water-based inks B and C. (Evaluation criteria) ◎: After cleaning with cleaning solution and refilling with ink, the nozzle check printing showed no scattering (curvature) or missing dots. ○: After cleaning with cleaning solution and refilling with ink, the nozzle check printing showed 1 to 2 scattering (curvature) or missing dots. △: After cleaning with cleaning solution and refilling with ink, the nozzle check printing showed 3 to 4 scattering (curvature) or missing dots. ×: After cleaning with cleaning solution and refilling with ink, the nozzle check printing showed 5 or more scattering (curvature) or missing dots.

[0057]

[0058]

[0059]

[0060] The cleaning solutions of the examples in which (1) the content ratio (mass ratio) of the polyhydric alcohols to the glycol ethers was 3 or more, (2) the content of water contained in the cleaning solution was 65 mass % or more relative to 100 mass % of the cleaning solution, and (3) the surface tension of the cleaning solution was 30 mN / m or more and 45 mN / m or less, had excellent detergency for all of the fixed deposits of aqueous inks A, B, and C, each containing 5 to 10 mass % of a binder component. On the other hand, the cleaning solutions of Comparative Examples 1, 3, and 5, which did not satisfy the above conditions (1) and (3), the cleaning solution of Comparative Example 2, which did not satisfy the above condition (3), and the cleaning solution of Comparative Example 4, which did not satisfy the above conditions (2) and (3), had poor detergency.

[0061] The cleaning liquid for an inkjet recording apparatus of the present invention exhibits excellent cleaning power for any ink, but is particularly suitable for use with textile printing inks, inks containing a large amount of binder components (for example, 5% by mass or more), or inks containing polyhydric alcohols, glycol ethers, and water.

Claims

1. A cleaning liquid for an inkjet recording device, comprising: a polyhydric alcohol; a glycol ether; and water, a content ratio (mass ratio) of the polyhydric alcohols to the glycol ethers is 3 or more, The content of water contained in the cleaning solution is 65% by mass or more relative to 100% by mass of the cleaning solution, The surface tension of the cleaning liquid is 30 mN / m or more and 45 mN / m or less, The cleaning liquid for an inkjet recording device, wherein the cleaning liquid is used for cleaning an inkjet recording device that uses an aqueous ink, the aqueous ink being an ink containing 5% by mass or more of a binder.

2. The cleaning solution described in claim 1, further containing 0.01 mass % or more and 0.5 mass % or less of a basic compound.

3. A cleaning solution as described in claim 1 or 2, wherein the content ratio (mass ratio) of the polyhydric alcohols to the glycol ethers is 4.5 or more.

4. The cleaning solution according to claim 1 or 2, wherein the polyhydric alcohols include dihydric alcohols and / or trihydric alcohols.

5. A cleaning solution as described in claim 1 or 2, wherein the polyhydric alcohols include dihydric alcohols.

6. The cleaning solution according to claim 1 or 2, wherein the glycol ethers include glycol monoalkyl ethers.

7. A cleaning solution as described in claim 1 or 2, wherein the glycol ethers include dipropylene glycol monomethyl ether or tripropylene glycol monomethyl ether.

8. The cleaning solution of claim 1 or 2, wherein the aqueous ink comprises an emulsion.

9. A cleaning solution as described in claim 1 or 2, wherein the water-based ink is a pigment printing ink.

10. A cleaning solution as described in claim 1 or 2, wherein the water-based ink has a surface tension of 26 to 29.

11. The cleaning solution of claim 1 or 2, wherein the aqueous ink contains an acrylic or urethane binder.

12. A cleaning solution as described in claim 1 or 2, wherein the aqueous ink contains an acrylic binder.

13. A method for cleaning an inkjet recording device using a composition comprising a polyhydric alcohol, a glycol ether, and water, comprising the steps of: a content ratio (mass ratio) of the polyhydric alcohols to the glycol ethers is 3 or more, The content of water contained in the composition is 65% by mass or more relative to 100% by mass of the composition, The surface tension is 30 mN / m or more and 45 mN / m or less, The composition is used for cleaning an inkjet recording device that uses an aqueous ink, and the aqueous ink contains 5% by mass or more of a binder. A method for cleaning an inkjet recording device.