Cleaning liquid for inkjet recording device

Abstract

The cleaning liquid for an ink jet recording device according to the present invention contains a polyol, a glycol ether, and water; the content ratio of the polyhydric alcohol to the glycol ether is more than 3; the content of water in the cleaning solution is 65% by mass or more with respect to 100% by mass of the cleaning solution; and the surface tension of the cleaning liquid is 30 mN / m to 45 mN / m.

Description

Technical Field

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

[0002] In an inkjet recording device, ink is ejected in the form of droplets from a large number of nozzles formed in an inkjet head toward a recording medium, and is fixed to the recording medium, thereby performing recording. If ink adhesion occurs within the device, for example, due to water evaporation, this causes clogging on the nozzle surface of the inkjet head or in the ink line of a filter or the like in the line, resulting in ink ejection failure. The nozzle surface to which ink adhesion has occurred is cleaned, for example, by applying a cleaning liquid to the surface and then wiping the surface.

[0003] Patent Document 1 describes a maintenance liquid (cleaning liquid) containing a given amount of a liquid having an SP value of 26 MPa. 1 / 2 The above water-soluble organic solvents have an SP value of 24 MPa 1 / 2 The following water-soluble organic solvents and water. In Examples, after ink ejection, the maintenance liquid loaded in the inkjet printer was applied to the nozzle surface of the inkjet head using a roller, and then the nozzle surface of the inkjet head was wiped with a wiping sheet (hydrogenated NBR), and then the cleaning performance was confirmed.

[0004] Patent document 2 describes a cleaning liquid for cleaning an inkjet recording device, the cleaning liquid containing a nonionic surfactant having a solubility of less than 0.2% by mass in water at 20°C, 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 satisfying a specific relationship. In the examples, the cleaning liquids of the examples and comparative examples were brought into contact with aqueous ink after an amount corresponding to 30% had evaporated, and the contact interface was visually inspected. The cleaning performance was confirmed based on the presence or absence of agglomerates in the contact surface.

[0005] Patent document 3 describes an ink set for inkjet recording, which contains an aqueous ink and an aqueous cleaning liquid, and wherein the aqueous cleaning liquid contains a nonionic surfactant having an amino group in the molecule, and the surface tension of the aqueous ink and the surface tension of the aqueous cleaning liquid satisfy a given relationship (A). In the embodiment, after a printing fastness test has been performed under the condition of a conveying speed of 350 mm / sec in an environment with a temperature of 25°C and a humidity of 60% RH, the aqueous cleaning liquid of the embodiment or the comparative example is supplied to the nozzle surface, and then a purging operation and a wiping operation are performed. The cleaning performance is confirmed based on whether the nozzle surface has ink dirt.

[0006] On the other hand, in order to restore the inkjet head nozzle contaminated by ink attachment or the ink line of the in-line filter, for example, which has been contaminated by ink attachment, there is a method of filling the nozzle with a cleaning liquid to clean the nozzle. Patent document 4 describes a filling liquid for an inkjet print head, which contains a specific amount of an alkylene oxide adduct showing a specific HLB and a specific amount of a moisturizer and water, and the filling liquid for the inkjet print head has a specific viscosity and a specific pH. In an embodiment, a recording head filled with an aqueous inkjet ink composition (pigment concentration: 12% by mass; pigment / alkali-soluble resin (mass) = 10 / 4) is allowed to stand in a 50°C oven for 3 months, thereby causing it to have an ink ejection failure, and the recording head is filled with each of the cleaning liquids (pH 9 to 13) of the embodiment and the comparative example in the initial filling mode. The cleaning performance is confirmed based on the performance of alleviating or eliminating the ejection failure.

[0007] There is still a desire for a cleaning liquid for an inkjet recording apparatus having better cleaning ability.

[0008] Reference List

[0009] Patent Literature

[0010] Patent Document 1: JP 2013-10267A

[0011] Patent document 2: JP2020-196781 A

[0012] Patent Document 3: JP2018-119078 A

[0013] Patent Document 4: JP2018-1510 A Summary of the invention

[0014] Technical issues

[0015] Therefore, the present invention solves the problem of providing a cleaning liquid for an inkjet recording apparatus having excellent cleaning ability.

[0016] Solution to the problem

[0017] The present inventors have conducted intensive research to solve this problem. As a result, the present inventors have found that this problem can be solved by using a cleaning liquid for an inkjet recording device, the cleaning liquid comprising a polyol, a glycol ether and water, wherein the glycol ether and the polyol have a specific content ratio, the water is contained in a specific amount, and the cleaning liquid has a specific surface tension. Thus, the present invention has been completed.

[0018] That is, the cleaning liquid for an inkjet recording device according to the present invention contains a polyol, a glycol ether and water, wherein the content ratio (mass ratio) of the polyol to the glycol ether is 3 or more, and 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 or more and 45 mN / m or less.

[0019] Advantageous Effects of the Invention

[0020] The present invention can provide a cleaning liquid for an inkjet recording apparatus having excellent cleaning ability. DETAILED DESCRIPTION

[0021] The cleaning liquid for an inkjet recording device of the present invention (hereinafter sometimes simply referred to as "cleaning liquid") is a cleaning liquid for an inkjet recording device, the cleaning liquid comprising a polyol, a glycol ether and water, wherein the content ratio (mass ratio) of the polyol to the glycol ether is 3 or more, and 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 or more and 45 mN / m or less.

[0022] In the cleaning liquid of the present invention, (1) the content ratio (mass ratio) of the polyol to the glycol ether is 3 or more, and (2) the content of water in the cleaning liquid is 65% by mass or more relative to 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. Therefore, a cleaning liquid for an inkjet recording device having excellent cleaning ability can be provided.

[0023] The cleaning liquid of the present invention has excellent cleaning capability for the inkjet head nozzles and the ink lines in the filters in the lines, etc., which have been contaminated by the attached ink.

[0024] The cleaning liquid of the present invention is suitable for use as a cleaning liquid for an inkjet recording apparatus which preferably uses an ink containing a large amount (eg, 5% by mass or more) of a binder component, such as an ink for inkjet textile printing (textile printing ink).

[0025] Furthermore, the cleaning liquid of the present invention has excellent safety despite its high cleaning ability since it contains polyol, glycol ether and water as main components.

[0026] As the polyhydric alcohol contained in the cleaning liquid of the present invention, diol or triol is particularly preferred.

[0027] Preferred among the diols are diols. Preferred among the diols are: chain aliphatic 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; and cyclic aliphatic diols such as 1,2-cyclohexanediol and 1,4-cyclohexanediol. Chain aliphatic diols are more preferred. Still more preferred among these are diethylene glycol, triethylene glycol and propylene glycol.

[0028] Preferred among the trihydric alcohols is glycerol.

[0029] Preferred among the polyols are diethylene glycol, triethylene glycol, propylene glycol and glycerol.

[0030] Only one of the polyols may be used, or two or more thereof may be used in combination. The inclusion of the polyol can impart moisturizing properties (non-drying properties) to the cleaning liquid.

[0031] The content of the polyol in the cleaning liquid is preferably 0.5% to 30% by mass, more preferably 5% to 27% by mass, relative to 100% by mass of the cleaning liquid. When two or more polyols are used, the content is the total content of these polyols.

[0032] As the glycol ether contained in the cleaning liquid of the present invention, glycol alkyl ethers are preferred. Among these, glycol monoalkyl ethers, glycol dialkyl ethers and glycol monoalkyl ether monoacetates are preferred. Glycol monoalkyl ethers and glycol dialkyl ethers are more preferred. Glycol monoalkyl ethers are particularly preferred.

[0033] The alkyl chain in these glycol alkyl ethers (glycol monoalkyl ether, glycol dialkyl ether and glycol monoalkyl ether acetate) is preferably an alkyl chain having 1 to 8 carbon atoms, more preferably an alkyl chain having one or 4 to 6 carbon atoms.

[0034] As the glycol monoalkyl ether, preferred are: ethylene glycol ether compounds such as ethylene glycol ether, diethylene glycol ether and triethylene glycol ether; or propylene glycol ether compounds such as propylene glycol ether, dipropylene glycol ether and tripropylene glycol ether. More preferred are propylene glycol ether compounds.

[0035] Preferred among the glycol ether compounds are diethylene glycol ether and triethylene glycol ether, and particularly preferred are diethylene glycol monobutyl ether and triethylene glycol monobutyl ether.

[0036] Preferred among the propylene glycol ether compounds are dipropylene glycol ether and tripropylene glycol ether, and particularly preferred are dipropylene glycol monomethyl ether and tripropylene glycol monomethyl ether.

[0037] Only one of these glycol ethers may be used, or two or more thereof may be used in combination. Due to the inclusion of the glycol ether, the cleaning liquid can be given penetrability to the attached ink components (pigment, binder).

[0038] The content of glycol ether in the cleaning liquid is preferably 0.5% to 10% by mass, more preferably 0.7% to 5% by mass, relative to 100% by mass of the cleaning liquid. When two or more glycol ethers are used, the content is the total content of these glycol ethers.

[0039] The content ratio (mass ratio) of the polyol to the glycol ether is 3 or more, more preferably 4.5 or more, still more preferably 6 or more. Such a content ratio enables a cleaning liquid with high cleaning ability to be obtained. For the same reason, the upper limit of the content ratio is preferably 30 or less, more preferably 20 or less, still more preferably 15 or less.

[0040] The water content in the cleaning liquid of the present invention is 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 relative to 100% by mass of the cleaning liquid. By adjusting the water content to a value within such a range, the cleaning ability of the cleaning liquid can be improved.

[0041] The surface tension of the cleaning liquid is 30 mN / m to 45 mN / m, preferably 30 mN / m to 40 mN / m. By adjusting the surface tension of the cleaning liquid to a value within such a range, the cleaning ability of the cleaning liquid can be improved.

[0042] The cleaning solution preferably also contains an alkaline compound. The inclusion of an alkaline compound can further improve the cleaning ability of the cleaning solution.

[0043] As the basic compound, inorganic basic compounds and organic basic compounds can be used. Among these, inorganic basic compounds are preferred.

[0044] As the organic base compound, preferred are ammonia, alkanolamines, alkylamines, etc. Preferred among these are ammonia, triethylamine, N,N-dimethylaminoethanol, N,N-dibutylaminoethanol, N-methyldiethanolamine, 2-amino-2-methylpropanol, diethanolamine, triethanolamine, N-methylaminoethanol, and N,N-diethylaminoethanol.

[0045] As the inorganic alkali compound, preferred are hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; carbonates such as potassium carbonate and sodium carbonate; and bicarbonates such as potassium bicarbonate and sodium bicarbonate (sodium bicarbonate). Among these, bicarbonates are preferred, and sodium bicarbonate (sodium bicarbonate) is more preferred.

[0046] The content of the alkaline compound is preferably 0.01% to 0.5% by mass, more preferably 0.05% to 0.3% by mass, relative to 100% by mass of the cleaning liquid. By adjusting the content of sodium bicarbonate to a value within such a range, the cleaning ability of the cleaning liquid can be further improved.

[0047] The cleaning solution preferably also contains a surfactant. The inclusion of a surfactant can further improve the cleaning ability of the cleaning solution. Relative to 100% by mass of the cleaning solution, 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. By adjusting the content of the surfactant to a value within such a range, the cleaning ability of the cleaning solution can be further improved.

[0048] Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and polymeric surfactants. One of these surfactants can be used alone, or two or more thereof can be combined. As surfactants, anionic surfactants or nonionic surfactants are preferred. More preferred is nonionic surfactant.

[0049] Examples of anionic surfactants include: alkyl sulfates, such as ammonium dodecyl sulfate and sodium dodecyl sulfate; alkyl sulfonates, such as ammonium dodecyl sulfonate, sodium dodecyl sulfonate and sodium alkyl (diphenyl ether) disulfonate; alkyl aryl sulfonates, such as ammonium dodecylbenzene sulfonate and sodium dodecylnaphthalene sulfonate; polyoxyethylene alkyl sulfonates; polyoxyethylene alkyl sulfates; polyoxyethylene alkyl aryl sulfates; dialkyl sulfosuccinates; aryl sulfonic acid / formalin condensates; fatty acid salts, such as ammonium laurate and sodium stearate; sulfuric acid esters or salts of esters having an alkyl group, such as bis (polyoxyethylene polycyclic phenyl ether) methacrylate sulfonates, allyl alkyl sulfosuccinates, (meth) acrylic acid polyoxyethylene sulfonates, (meth) acrylic acid polyoxyethylene phosphates and sulfonates of allyloxymethyl alkyloxy polyoxyethylene; and sulfuric acid ester salts of allyloxymethyl alkoxyethyl polyoxyethylene, and polyoxyalkylene alkenyl ether sulfate ammonium salts. However, anionic surfactants are not limited to these examples.

[0050] The example of nonionic surfactant comprises: the condensation product of polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyethylene glycol and polypropylene glycol, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid monoglyceride, condensation product of ethylene oxide and aliphatic amine, allyloxymethyl alkoxyethyl hydroxy polyoxyethylene, polyoxyalkylene alkenyl ether, acetylene glycol compound and acetylene alcohol compound. However, nonionic surfactant is not limited to these examples. For example, the commercial product of nonionic surfactant can be used. The example of commercial product comprises: "Emulgen (registered trademark) 108" (polyoxyethylene lauryl ether) (produced by Kao Corporation), "Olfine (registered trademark) E1004 (acetylene glycol compound) (produced by Nissin Chemical Industry Co., Ltd.), and "Nonion EH-204" (polyoxyethylene 2-ethylhexyl ether) (produced by NOF Corporation).

[0051] Examples of the cationic surfactant include alkylammonium salts such as dodecylammonium chloride. However, the cationic surfactant is not limited to these examples.

[0052] Examples of the amphoteric surfactant include betaine ester type surfactants. However, the amphoteric surfactant is not limited to these examples.

[0053] Examples of polymeric surfactants include: poly(meth)acrylates, such as poly(sodium acrylate); poly(vinyl alcohol); polyvinyl pyrrolidone; poly(hydroxyalkyl (meth)acrylates), such as poly(hydroxyethyl acrylate); and copolymers each including one or more of the monomers used to form these polymers (as one or more copolymerization components). However, polymeric surfactants are not limited to these examples.

[0054] The cleaning liquid 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 improve the dispersibility of the pigment component contained in the ink.

[0055] As the acid, poly((meth)acrylic acid) and aliphatic carboxylic acids are preferred. Preferred examples of 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. As the salt, alkali metal salts of these acids are preferred. Sodium salts are more preferred. Examples thereof include poly(sodium acrylate), sodium tricarballylic acid, sodium succinate, sodium acetate, and sodium formate.

[0056] There is no particular limitation on the content of the acid and the content of the acid salt. However, 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 liquid.

[0057] The cleaning liquid of the present invention may further contain a preservative. As the preservative, a commonly known preservative may be used. Preferred examples thereof include: isothiazolinone-based preservatives, such as methylisothiazolinone; carbamate compounds, such as iodopropyl butylcarbamate; pyrithione compounds, such as sodium pyrithione; and benzimidazole compounds, such as thiabendazole.

[0058] 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 liquid.

[0059] According to the cleaning liquid for inkjet recording apparatus of the present invention, a cleaning liquid for inkjet recording apparatus with excellent cleaning ability can be provided. The cleaning liquid for inkjet recording apparatus of the present invention is also suitable as a cleaning liquid for inkjet recording apparatus in which inkjet ink (textile printing ink) for pigment textile printing applications is used. Since the inkjet ink for pigment textile printing applications needs to have high fastness, these inkjet inks contain a large amount of binder components, and once the binder components are attached to the head, it is particularly difficult to restore these heads. The cleaning liquid for inkjet recording apparatus of the present invention also has excellent cleaning ability for these inks.

[0060] Although the cleaning liquid for inkjet recording devices of the present invention exhibits excellent cleaning ability for any ink, the cleaning liquid is particularly suitable for inks for textile printing, inks containing a large amount (e.g., 5% by mass or more) of a binder component, or inks containing polyols, glycol ethers, and water.

[0061] The present disclosure also provides a method for cleaning an inkjet recording device, the method comprising using a composition comprising a polyol, a glycol ether and water, wherein the content ratio (mass ratio) of the polyol to the glycol ether is 3 or more, and the content of the water is 65% by mass or more relative to 100% by mass of the composition, and the surface tension of the composition is 30 mN / m or more and 45 mN / m or less. By this method for cleaning an inkjet recording device, the feed line and the inkjet head nozzle of the inkjet recording device can be efficiently cleaned.

[0062] The method for cleaning an inkjet recording apparatus is particularly suitable for cleaning an inkjet recording apparatus in which a textile printing ink, a binder containing a large amount (eg, 5% by mass or more) of a binder component, or an ink containing a polyol, a glycol ether, and water is used.

[0063] The preferred embodiments of the composition to be used in the method for cleaning an inkjet recording device (e.g., the polyol and glycol ether in the composition, the content ratio therebetween, the water content ratio, the surface tension, etc.) are independently the same as the preferred embodiments described above for the cleaning liquid for an inkjet recording device of the present invention (e.g., the polyol and glycol ether in the cleaning liquid, the content ratio therebetween, the water content ratio, the surface tension, etc.).

[0064] In addition to using the composition, there is no particular restriction on the device for cleaning the inkjet recording device. The example of the cleaning method includes: a method in which a bottle containing a given amount of the composition is used to replace the ink bottle that has been used and the composition is passed through the ink feed line and the inkjet head nozzle in a given period of time. In this case, after the composition is passed through, the effect of cleaning is confirmed by replacing the bottle with an ink bottle and checking printing. In addition to replacing with an ink bottle, the bottle containing a given amount of the composition can be installed in another position so that the composition is appropriately flowed through the ink line. In this case, after the composition is passed through, the effect of cleaning is confirmed by passing the ink through the ink feed line and the inkjet head nozzle to check printing.

[0065] The method for cleaning an inkjet recording apparatus according to the present disclosure enables a sufficient cleaning effect to be obtained even when the amount of the composition used for cleaning is small and / or the cleaning time is short.

[0066] The present disclosure further provides the use of a composition comprising a polyol, a glycol ether and water as a cleaning liquid for an inkjet recording device, wherein the content ratio (mass ratio) of the polyol to the glycol ether is 3 or more, and the content of the water is 65% by mass or more relative to 100% by mass of the composition, and the surface tension of the composition is 30 mN / m or more and 45 mN / m or less. The use of the composition as a cleaning liquid for an inkjet recording device enables efficient cleaning of a feed line and an inkjet head nozzle of an inkjet recording device.

[0067] The use of the composition as a cleaning liquid for inkjet recording apparatus is particularly suitable for cleaning inkjet recording apparatus in which textile printing ink, a binder containing a large amount (e.g., 5% by mass or more) of a binder component, or an ink containing a polyol, a glycol ether, and water is used.

[0068] The preferred embodiments of the composition in its use as a cleaning liquid for an inkjet recording device (for example, the polyol and glycol ether in the composition, the content ratio therebetween, the water content ratio, the surface tension, etc.) are independently the same as the preferred embodiments described above for the cleaning liquid for an inkjet recording device of the present invention (for example, the polyol and glycol ether in the cleaning liquid, the content ratio therebetween, the water content ratio, the surface tension, etc.).

[0069] Example

[0070] The present invention is described in more detail below by way of examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" are "parts by mass" and "% by mass", respectively.

[0071] The measuring method and the evaluation method are as follows.

[0072] <Average Particle Size of Resin Emulsion Particles>

[0073] The resin emulsion was measured using a particle size distribution analyzer based on a dynamic light scattering method [Product No.: nanoSAQLA, manufactured by Otsuka Electronics Co., Ltd.] to determine the volume particle size distribution. The average particle size thus obtained by cumulative analysis was taken as the average particle size of the resin emulsion particles.

[0074] <Average Particle Size of Pigment>

[0075] The pigment dispersion was measured using a particle size distribution analyzer based on a dynamic light scattering method [Product No.: nanoSAQLA, manufactured by Otsuka Electronics Co., Ltd.] to determine the volume particle size distribution. The average particle diameter thus obtained by the cumulative analysis method was taken as the average particle diameter of the pigment.

[0076] <Ink Viscosity>

[0077] Aqueous inks A to C, which will be described later, were measured using an E-type viscometer TPE-100 (manufactured by Toki Sangyo Co., Ltd.) under the conditions of rotor R24, 0.8 degrees, and 25°C.

[0078] <pH of cleaning solution>

[0079] The cleaning liquids of Examples 1 to 13 and Comparative Examples 1 to 5 were respectively measured at 25°C using a pH meter (G1500, manufactured by Greisinger GmbH).

[0080] <Surface tension of cleaning fluid>

[0081] The surface tensions of the cleaning liquids of Examples 1 to 13 and Comparative Examples 1 to 5 at 25° C. were respectively measured by the Wilhelmy method using a surface tensiometer DY-500 (manufactured by Kyowa Interface Science Co., Ltd.).

[0082] <Emulsion Preparation Example>

[0083] [Emulsion Preparation Example 1]

[0084] 252 parts by mass of deionized water were introduced into a flask equipped with a dropping funnel, a stirrer, a nitrogen introduction tube, a thermometer and a reflux condenser. A pre-emulsion for dropping consisting of 437 parts by mass of deionized water, 80 parts by mass of an aqueous solution of a 25% emulsifier [trade name ADEKA REASOAP SR-10, produced by ADEKA Corp.], 25 parts by mass of acrylic acid, 565 parts by mass of 2-ethylhexyl acrylate, 50 parts by mass of cyclohexyl methacrylate, 10 parts by mass of hydroxyethyl methacrylate and 350 parts by mass of styrene was prepared, and 44 parts by mass of the pre-emulsion (equivalent to 3% of all monomer components) were introduced into the flask. While nitrogen was slowly fed therein, the contents were heated to 80°C. 30 parts by mass of a 5% aqueous solution of ammonium persulfate were added thereto to initiate polymerization. Afterwards, the remainder of the pre-emulsion for dropping and 30 parts by mass of a 5% aqueous solution of ammonium persulfate were uniformly dripped into the flask within 240 minutes. After the dropwise addition was completed, the contents of the flask were maintained at 80°C for 180 minutes, and 25% ammonia water and deionized water were added thereto to adjust the pH to 8.5 and the solid content to 50%. Thus, the polymerization was completed. The resulting reaction solution was cooled to room temperature and then filtered with a 300-mesh metal mesh to obtain an emulsion (emulsion: acrylic resin). The emulsion had a solid (resin emulsion particles) content of 50% and a Tg of -21°C. The average particle size of the resin emulsion particles was 200 nm.

[0085] <Pigment Dispersion Preparation Example>

[0086] [Pigment Dispersion Preparation Example 1]

[0087] 5 parts by mass of a dispersant Discoat N-14 (produced by Dai-ichi Kogyo Seiyaku Co., Ltd.), 6 parts by mass of propylene glycol, 70 parts by mass of deionized water, 100 parts by mass of titanium oxide CR-95 (produced by Ishihara SangyoKaisha, Ltd.), and 50% by volume of zirconium oxide beads having a particle size of 0.5 mm were charged into a bead mill and dispersed using the bead mill to obtain a white pigment dispersion (pigment dispersion: titanium oxide) having a pigment content of 55%. In the obtained white pigment dispersion, the average particle size of the pigment was 330 nm.

[0088] [Pigment dispersion preparation example 2]

[0089] 3 parts by mass of dispersant Joncryl 678 (produced by BASF AG), 1.3 parts by mass of dimethylaminoethanol and 81 parts by mass of deionized water were stirred together at 70°C to mix. Subsequently, 15 parts by mass of blue pigment CI PigmentBlue 15:3 LIONOL BLUE FG-7330 (produced by Toyo Ink Mfg. Co., Ltd.), 0.1 parts by mass of surfactant Olfine D-10PG (produced by Nissin Chemical Industry Co., Ltd.) and 50% by volume of zirconium oxide beads with a particle size of 0.5 mm were loaded into a bead mill and dispersed using the bead mill. The resulting mixture was filtered with a filter (MCP-1-C10S, produced by Advantec Co.) having a pore size of 1 μm, thereby obtaining a blue pigment dispersion (pigment dispersion: cyan pigment) with a pigment content of 15%. In the resulting blue pigment dispersion, the average particle size of the pigment was 90 nm.

[0090] <Example of water-based ink preparation>

[0091] [Preparation Example of Water-Based Ink A]

[0092] Deionized water was added to 20 parts by mass of the acrylic resin emulsion of Emulsion Preparation Example 1 (10 parts by mass in terms of the amount of resin emulsion particles), 25 parts by mass of the pigment dispersion of Pigment Dispersion Preparation Example 1 (14 parts by mass in terms of the amount of pigment), 15 parts by mass of triethylene glycol, 3.0 parts by mass of diethylene glycol monobutyl ether, and 1.0 parts by mass of surfactant Olfin E1004 (produced by Shin-Etsu Chemical Co., Ltd.) to obtain 100 parts by mass. The components were mixed together and filtered with a filter having a pore size of 1 μm (MCP-1-C10S, produced by Advantec Co.), thereby preparing aqueous ink A.

[0093] [Preparation Example of Water-Based Ink B]

[0094] Deionized water was added to 17 parts by mass of Takelac W6010 (produced by Mitsui Chemicals, Inc.; solid content 30%) as a urethane resin emulsion (emulsion: urethane) (5 parts by mass in terms of the amount of resin emulsion particles), 25 parts by mass of the pigment dispersion of Pigment Dispersion Preparation Example 1 (14 parts by mass in terms of the amount of pigment), 15 parts by mass of triethylene glycol, 3 parts by mass of diethylene glycol monobutyl ether, and 1.0 parts by mass of surfactant Olfine E1004 (produced by Shin-Etsu Chemical Co., Ltd.) to obtain 100 parts by mass. The components were mixed together and filtered with a filter having a pore size of 1 μm (MCP-1-C10S, produced by Advantec Co.), thereby preparing an aqueous ink B.

[0095] [Preparation Example of Water-Based Ink C]

[0096] Deionized water was added to 20 parts by mass of the acrylic resin emulsion of Emulsion Preparation Example 1 (10 parts by mass in terms of the amount of resin emulsion particles), 23 parts by mass of the pigment dispersion of Pigment Dispersion Preparation Example 2 (3.5 parts by mass in terms of the amount of pigment), 15 parts by mass of triethylene glycol, 3.0 parts by mass of diethylene glycol monobutyl ether, and 1.0 parts by mass of surfactant Olfin E1004 (produced by Shin-Etsu Chemical Co., Ltd.) to obtain 100 parts by mass. The components were mixed together and filtered with a filter having a pore size of 1 μm (MCP-1-C10S, produced by Advantec Co.), thereby preparing aqueous ink C.

[0097] Table 1 shows the formulations of the prepared inks.

[0098] [Table 1]

[0099] Table 1

[0100]

[0101] [Example 1]

[0102] (Preparation of cleaning solution)

[0103] 20 parts by mass of triethylene glycol, 3 parts by mass of diethylene glycol monobutyl ether, 0.1 parts by mass of surfactant Olfin E1004 (produced by Shin-Etsu Chemical Co., Ltd.) and 76.9 parts by mass of deionized water were mixed together. The mixture was filtered with a filter having a pore size of 1 μm (MCP-1-C10S, produced by Advantec Co.), thereby preparing a cleaning liquid (1).

[0104] [Examples 2 to 13 and Comparative Examples 1 to 5]

[0105] 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 prepared in the same manner as in Example 1, except that the types and amounts of the components in Example 1 of "(Preparation of cleaning solution)" were changed as shown in Tables 2 to 4 and the total amount was adjusted to 100 parts by mass by adjusting the amount of deionized water to be introduced.

[0106] The nozzle recovery performance of the head of the cleaning liquids prepared in these Examples and Comparative Examples was evaluated according to the following evaluation criteria.

[0107] <Evaluation of jet failure improvement performance>

[0108] Aqueous ink A was filled into a textile printer MMP-TX13 (produced by Mastermind Co.), and three pieces of cotton fabric (100% cotton white T-shirts produced by Hanes, Inc.) were continuously printed with a solid area of ​​120 mm × 120 mm at 1440 dpi × 1440 dpi and a set printing speed of 8. Thus, it was confirmed that the inkjet head was filled with ink. After that, the inkjet head in an uncapped state was left to stand for one week in an environment with a temperature of 23° C. and a humidity of 50%. Standing without a cap allowed the ink to dry and adhere firmly. After standing, nozzle check printing was performed (all 180 nozzles were continuously ejected to print grid lines). As a result, it was confirmed that more than 10 nozzles had scattering (deflection) or dot skipping due to ink ejection failure.

[0109] The recording head having ink ejection failure was filled with each cleaning liquid of Examples 1 to 13 and Comparative Examples 1 to 5 for 10 minutes in the filling mode, and cleaned therewith. Thereafter, aqueous ink A was filled into the head again, and nozzle check printing was performed. The improvement performance of ejection failure was evaluated according to the following evaluation criteria.

[0110] The same evaluation was performed on aqueous inks B and C.

[0111] (Evaluation Criteria)

[0112] ⊚: There was no scattering (deviation) and missing dots in the nozzle check printing after cleaning with the cleaning liquid and refilling of the ink.

[0113] ○: There were one or two scattering (deviation) and missing dots in the nozzle check printing after cleaning with the cleaning liquid and ink refilling.

[0114] Δ: There are three or four scattering (deviation) and missing dots in the nozzle check printing after cleaning with the cleaning liquid and ink refilling.

[0115] ×: There are five or more scattering (deviation) and missing dots in the nozzle check printing after cleaning with the cleaning liquid and ink refilling.

[0116] [Table 2]

[0117] Table 2

[0118]

[0119] [Table 3]

[0120] Table 3

[0121]

[0122] [Table 4]

[0123] Table 4

[0124]

[0125] The cleaning liquid of the embodiments has excellent cleaning ability against the attached residues of each of the aqueous inks A, B and C (each of which contains 5-10% by mass of the binder component), and each of the cleaning liquids of the embodiments satisfies: (1) the content ratio (mass ratio) of the polyol to the glycol ether is 3 or more, and (2) the water content is 65% by mass or more relative to 100% by mass of the cleaning liquid, and (3) the surface tension of each of the cleaning liquids is 30 mN / m or more and 45 mN / m or less.

[0126] On the other hand, the cleaning liquids of Comparative Examples 1, 3 and 5 that do not satisfy (1) and (3) above, the cleaning liquid of Comparative Example 2 that does not satisfy (3) above, and the cleaning liquid of Comparative Example 4 that does not satisfy (2) and (3) above have poor cleaning capabilities.

[0127] Industrial Applicability

[0128] The inkjet recording device cleaning liquid of the present invention exhibits excellent cleaning ability for any ink, but is particularly suitable for textile printing ink, ink containing a large amount (eg, 5% by mass or more) of a binder component, or ink containing a polyol, a glycol ether, and water.

Claims

1. A cleaning liquid for an inkjet recording device, the cleaning liquid for an inkjet recording device comprising a polyol, a glycol ether and water, wherein The content ratio (mass ratio) of the polyol to the glycol ether is 3 or more, The water content 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 greater than or equal to 30 mN / m and less than or equal to 45 mN / m.

2. The cleaning fluid of claim 1, wherein the polyol comprises a diol and / or a triol.

3. The cleaning fluid of claim 1 or 2, wherein the glycol ether comprises a glycol monoalkyl ether. The cleaning solution according to claim 1 , further comprising an alkaline compound. The cleaning solution according to claim 3 , further comprising an alkaline compound.

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