Inkjet recording method

Abstract

To provide an inkjet recording device that has satisfactory maintainability of a recording head even if ink containing water-soluble polymers is used, and is capable of forming an image having excellent image density.SOLUTION: An inkjet recording device has: ink containing water-soluble polymers in which a number average molecular weight Mn is 560 or more and 3,300 or less; a liquid discharge head having a nozzle surface for which a nozzle discharging ink is provided; cleaning liquid containing a compound which has a structure expressed by the following formula (1); an ejection member which ejects the cleaning liquid onto a nozzle surface; a pressurizing member which pressurizes ink to form droplets of the ink on the nozzle surface; and a blade member which contacts the nozzle surface and wipes the nozzle surface from which the cleaning liquid is ejected, where the content of water-soluble polymers is 11.0 mass % or more and 30.0 mass % or less for ink, and the content of the compound having the structure expressed by the above formula is 0.2 mass% or more and 1.5 mass% or less for the cleaning liquid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to inkjet How to record Regarding the law. [Background technology]

[0002] Inkjet printers have advantages such as low noise, low running costs, and ease of color printing, and are widely used as digital signal output devices. Inkjet printers use various materials as substrates, including absorbent recording media such as plain paper, low-absorbency recording media such as coated paper, and non-absorbent recording media such as plastic film. When printing on the aforementioned low-absorption recording medium, there is a problem in that the ink (hereinafter sometimes referred to as "inkjet composition") cannot spread sufficiently, resulting in a decrease in image quality. It is known that including a water-soluble polymer in the inkjet composition improves the spread of the inkjet composition and enhances image quality.

[0003] As an inkjet composition, for example, an inkjet ink composition has been proposed that contains at least one water-soluble polymer selected from the group consisting of polyethylene glycol and block copolymers of ethylene glycol and propylene glycol, having a number average molecular weight of 1,000 to 100,000, a polyfunctional (meth)acrylamide type polymerizable compound, a colorant, and water, for the purpose of recording images with excellent scratch resistance and flexibility (see, for example, Patent Document 1).

[0004] As an inkjet recording apparatus using the aforementioned inkjet composition, for example, an inkjet recording apparatus has been proposed that comprises: a recording head that ejects ink from an ejection port; an application means for applying ink to the surface on which the ejection port is formed on the recording head; a capping unit that caps the ejection port of the recording head; a suction means that applies pressure for suction to the recording head capped by the capping unit to perform suction; and a control means that controls the application means to apply ink to the surface on which the ejection port is formed before the suction operation is performed by the suction means. [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention provides an inkjet recording apparatus that allows for good maintenance of the recording head even with inks containing water-soluble polymers, and that can form images with excellent image density. [Means for solving the problem]

[0006] The inkjet recording apparatus of the present invention, as a means for solving the aforementioned problems, comprises an ink containing a water-soluble polymer having a number average molecular weight Mn of 560 or more and 3,300 or less, A liquid dispensing head having a nozzle surface on which a nozzle for dispensing the aforementioned ink is provided, A washing solution containing a compound having the structure represented by the following structural formula (1), [ka] A spraying member that sprays the cleaning liquid onto the nozzle surface, A pressurizing member that pressurizes the ink to form droplets of the ink on the nozzle surface, It comprises a blade member that contacts the nozzle surface and wipes the nozzle surface from which the cleaning liquid has been sprayed, The content of the water-soluble polymer is 11.0% by mass or more and 30.0% by mass or less relative to the ink. The content of the compound having the structure of structural formula (1) is 0.2% by mass or more and 1.5% by mass or less relative to the washing solution. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an inkjet recording apparatus that can form images with excellent image density and good maintainability of the recording head even when using ink containing water-soluble polymers. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an example of an inkjet recording apparatus according to the present invention and its maintenance operation. [Figure 2] Figure 2 is a schematic diagram showing an example of an inkjet recording apparatus according to the present invention. [Figure 3] Figure 3 is a schematic diagram showing an example of an inkjet recording device used in Comparative Example 14 and its maintenance operation. [Figure 4] Figure 4 is a schematic diagram showing an example of an inkjet recording device used in Comparative Example 15 and its maintenance operation. [Modes for carrying out the invention]

[0009] (Inkjet recording device and inkjet recording method) The inkjet recording apparatus of the present invention comprises ink, a liquid ejection head, a cleaning solution, a jetting member, a pressurizing member, and a blade member, and may have other members as needed. The inkjet recording method of the present invention comprises an ink ejection step, an ink spraying step, a pressurizing step, and a wiping step, and may include other steps as necessary. The recording device of the present invention may also be referred to as an image forming apparatus, an inkjet recording apparatus, an inkjet printer, a molding apparatus, etc.

[0010] It has been reported that in the inkjet ink composition described in Patent Document 1, an ink that does not contain a water-soluble polymer has deteriorated image quality when printed on high-quality paper, causing density unevenness and streaks. In the inkjet recording apparatus described in Patent Document 2, the resin adhering to the nozzle surface cannot be sufficiently removed only by applying ink.

[0011] Accordingly, as a result of intensive studies conducted by the present inventors, the present invention provides an ink containing a water-soluble polymer having a number average molecular weight Mn of 560 or more and 3,300 or less, a liquid discharge head having a nozzle surface provided with nozzles for discharging the ink, a cleaning liquid containing a compound having a structure represented by the following structural formula (1), an injection member that injects the cleaning liquid onto the nozzle surface, a pressure member that pressurizes the ink to form ink droplets on the nozzle surface, and a blade member that contacts the nozzle surface and wipes the nozzle surface onto which the cleaning liquid has been injected, wherein the content of the water-soluble polymer is 11.0% by mass or more and 30.0% by mass or less based on the ink, and the content of the compound having the structure of the structural formula (1) is 0.2% by mass or more and 1.5% by mass or less based on the cleaning liquid. It has been found that with this configuration, even with an ink containing a water-soluble polymer, the maintenance performance of the recording head is good, and an image excellent in image density can be formed.

[0012] Hereinafter, the recording apparatus according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and can be modified within the range that can be conceived by those skilled in the art, such as other embodiments, additions, modifications, deletions, etc., and any aspect is included in the scope of the present invention as long as it exhibits the functions and effects of the present invention.

[0013] Fig. 1 is a schematic diagram showing an example of an embodiment of an inkjet recording apparatus and an example of its maintenance operation. As the present embodiment, the apparatus includes, for example, a liquid discharge head 1, a blade member 2, and an injection member 3.

[0014] In the spraying step, as shown in FIG. 1, a cleaning liquid is sprayed onto the nozzle surface of the liquid ejection head 1. By performing the spraying step before the pressurizing step, ink contamination in the vicinity of the nozzle surface can be loosened. The spraying step can be performed by the spraying member 3.

[0015] In the pressurizing step, as shown in FIG. 1, ink is pressurized to form droplets of the ink on the nozzle surface of the liquid ejection head 1. By performing the pressurizing step, the ink on the nozzle surface can be discharged and contamination can be removed. The pressurizing step can be performed by a pressurizing member.

[0016] In the wiping step, as shown in FIG. 1, a blade member is brought into contact with the nozzle surface of the liquid ejection head 1 to wipe the nozzle surface onto which the cleaning liquid has been sprayed. By performing the wiping step, ink contamination on the nozzle surface can be removed together with the cleaning liquid by the blade member, and the nozzle can be brought into an ejectable state. The wiping step can be performed by the blade member 2.

[0017] FIG. 2 is a conceptual diagram illustrating a recording apparatus, in which a conveying means includes a paper feeding device 12, a winding device 13, and rollers 18. A recording medium (continuous form paper P) is conveyed between the paper feeding device 12 and the winding device 13, contacts the roller 18 serving as a conveying member, and is conveyed in the direction of the arrow. It should be noted that only one roller 18 is provided with a reference numeral, and the display of reference numerals for other rollers is omitted. In addition, the configuration of the rollers 18 is not limited to that illustrated, and can be changed as appropriate; for example, the number, arrangement, and the like can be changed as appropriate.

[0018] The liquid ejection head is not particularly limited and can be appropriately selected according to the purpose; examples thereof include an inkjet head. In FIG. 2, ink is ejected onto a recording medium using the inkjet head 14.

[0019] The IR heater 15 is an example of a heating means, which irradiates light onto the recording medium on which the ink has been ejected. By irradiating with light and heating, the water-based ink can be dried well. Preferably, the light used is IR light, which is in the wavelength range absorbed by water, in which case drying can be achieved quickly.

[0020] The exhaust means exhausts the air inside the enclosure. In this embodiment, the exhaust means includes, for example, an exhaust duct 17 and a fan. The exhaust duct 17 has an intake port for drawing in air from inside the enclosure, an exhaust port for discharging air, and so on.

[0021] The hot air device 5 blows hot air onto the recording medium on which the ink has been ejected. In the direction of transport of the recording medium, the ejection means, exhaust means, heating means, and hot air blowing means are arranged in that order from the upstream side. By arranging the hot air blowing means downstream of the heating means in particular, it is possible to suppress the obstruction of the airflow by the hot air to the steam generated by the heating means that would come into contact with the recording medium before it is heated.

[0022] The arrangement of the IR heater 15 and the exhaust duct 17 can be changed as appropriate. It is preferable that a path exists between the IR heater 15 and the suction port of the exhaust duct 17 for transporting the recording medium before it reaches the IR heater 15. In this case, the recording medium can be more reliably passed through the steam heated by the IR heater 15, making it easier for the recording medium to absorb moisture. Furthermore, the area between the IR heater 15 and the suction port of the exhaust duct 17 can also be described as being on a straight line connecting the IR heater 15 and the exhaust duct 17, and it is important to consider whether the transport path for the recording medium exists on such a straight line.

[0023] <ink> The following describes the organic solvents, water, colorants, resins, additives, etc., used in the ink. The ink used in the present invention contains a water-soluble polymer having a number-average molecular weight Mn of 560 or more and 3,300 or less, and preferably contains a colorant, an organic solvent, and water, and optionally contains other components.

[0024] -Water-soluble polymer- The aforementioned water-soluble polymer is a molecule with a number-average molecular weight (Mn) of 560 or more. The number-average molecular weight Mn of the water-soluble polymer is preferably 560 to 3,300 from the viewpoint of image density and maintainability, more preferably 900 to 3,300 from the viewpoint of image density, and particularly preferably 900 to 2,200 from the viewpoint of maintainability.

[0025] There are no particular restrictions on the method for measuring the number-average molecular weight Mn, and it can be appropriately selected depending on the purpose. For example, it can be measured by GPC (Gel Permeation Chromatography). The specific measurement conditions are as follows. [Measurement conditions] • Equipment: GPC-8020 (manufactured by Tosoh Corporation) • Columns: TSK G2000HXL and G4000HXL (manufactured by Tosoh Corporation) ·Temperature: 40℃ • Solvent: THF (tetrahydrofuran) Flow rate: 1.0 mL / min

[0026] The content of the water-soluble polymer is 11.0% by mass or more and 30.0% by mass or less relative to the ink, and from the viewpoint of image density and maintainability, 15.0% by mass or more and 20.0% by mass or less is more preferable. When the content is 11.0% by mass or more, the image density is excellent. When the content is 30.0% by mass or less, the maintainability is excellent.

[0027] The aforementioned water-soluble polymer is not particularly limited and can be appropriately selected depending on the purpose. Examples include polyethylene glycol and polypropylene glycol.

[0028] -Organic solvents- The organic solvent used in the present invention is not particularly limited, and water-soluble organic solvents can be used. Examples include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.

[0029] Specific examples of polyhydric alcohols include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, and 1,4-pentanediol. Examples include ethanol, 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, etc. Examples of polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether. Examples of nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone. Examples of amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide. Examples of amines include monoethanolamine, diethanolamine, and triethylamine. Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, and thiodiethanol. Other organic solvents include propylene carbonate and ethylene carbonate. It is preferable to use an organic solvent with a boiling point of 250°C or lower, as it not only functions as a wetting agent but also provides good drying properties.

[0030] -water- There are no particular restrictions on the water content, and it can be selected as appropriate depending on the purpose. However, from the viewpoint of ink drying properties and ejection reliability, 10% to 90% by mass is preferred, and 20% to 80% by mass is more preferred.

[0031] -Colorants- There are no particular restrictions on the colorants used; they can be selected appropriately depending on the purpose, and examples include pigments and dyes. There are no particular restrictions on the pigments used; they can be appropriately selected according to the purpose. Examples include inorganic pigments and organic pigments. These may be used individually or in combination of two or more. Mixed crystals may also be used as pigments. Examples of pigments that can be used include black pigment, yellow pigment, magenta pigment, cyan pigment, white pigment, green pigment, orange pigment, and glossy or metallic pigments such as gold and silver. As inorganic pigments, titanium dioxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chromium yellow can be used, as well as carbon black produced by known methods such as the contact method, furnace method, and thermal method. In addition, organic pigments such as azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye type chelates, acid dye type chelates, etc.), nitro pigments, nitroso pigments, and aniline black can be used. Of these pigments, those with good affinity for the solvent are preferred. Other uses such as resin hollow particles and inorganic hollow particles are also possible.

[0032] Specific examples of pigments include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, or metals such as copper, iron (CI Pigment Black 11), and titanium dioxide, as well as organic pigments such as aniline black (CI Pigment Black 1). Furthermore, for color applications, we have CI Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, and CI Pigment O Range 5, 13, 16, 17, 36, 43, 51, CI Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B(Ca)), 48:3, 48:4, 49:1, 52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88 , 101 (Bengara), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, CI Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38; CI Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3, 15:4 (Phthalocyanine Blue), 16, 17:1, 56, 60, 63; CI Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc. are available. The dyes used are not particularly limited and include acid dyes, direct dyes, reactive dyes, and basic dyes. They may be used individually or in combination of two or more types.

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

[0034] The colorant content in the ink is preferably 0.1% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 10% by mass or less, from the viewpoint of improving image density, good fixation and ejection stability.

[0035] Methods for obtaining ink by dispersing pigments include introducing hydrophilic functional groups into the pigment to create a self-dispersible pigment, coating the surface of the pigment with a resin and dispersing it, and using a dispersant to disperse it. One method for creating self-dispersible pigments by introducing hydrophilic functional groups into pigments is to add functional groups such as sulfone groups or carboxyl groups to a pigment (e.g., carbon) to make it dispersible in water. One method for coating and dispersing a pigment surface with a resin is to encapsulate the pigment in microcapsules, making it dispersible in water. This can be rephrased as a pigment whose surface is coated with a resin and dispersed (hereinafter sometimes referred to as "resin-coated pigment"). When coating and dispersing a pigment surface with a resin, it is not necessary for all pigments incorporated into the ink to be coated with resin; as long as the effects of the present invention are not impaired, uncoated pigments or partially coated pigments may be dispersed in the ink.

[0036] Methods of dispersion using dispersants include using well-known low-molecular-weight dispersants, such as surfactants, and high-molecular-weight dispersants. Depending on the pigment, dispersants such as anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants can be used. As a dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd., and sodium naphthalene sulfonate formalin condensate can also be suitably used as dispersants. Dispersing agents may be used individually or in combination of two or more.

[0037] -resin- There are no particular restrictions on the type of resin contained in the ink, and it can be appropriately selected according to the purpose. Examples include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Resin particles made from these resins may also be used. Ink can be obtained by mixing the resin particles, dispersed in water as a dispersion medium in a resin emulsion, with materials such as colorants and organic solvents. The resin particles may be synthesized as appropriate, or commercially available ones may be used. Furthermore, these may be used individually or in combination of two or more types of resin particles.

[0038] There are no particular restrictions on the volume-average particle size of the resin particles, and they can be appropriately selected depending on the purpose. However, from the standpoint of obtaining good adhesion and high image hardness, a size of 10 nm to 1,000 nm is preferred, 10 nm to 200 nm is more preferred, and 10 nm to 100 nm is particularly preferred.

[0039] The volume-average particle size can be measured, for example, using a particle size analyzer (NanoTrac Wave-UT151, manufactured by MicroTrac-Bell Co., Ltd.). There are no particular restrictions on the resin content; it can be selected appropriately depending on the purpose.

[0040] There are no particular restrictions on the particle size of the solids in the ink, and they can be appropriately selected depending on the purpose. However, to improve image quality such as ejection stability and image density, the maximum frequency of solid particles in the ink is preferably between 20 nm and 1,000 nm in terms of maximum number, and more preferably between 20 nm and 150 nm. The solids include resin particles, pigment particles, etc. The particle size can be measured using a particle size analyzer (NanoTrac Wave-UT151, manufactured by MicroTrac-Bell Co., Ltd.).

[0041] - Additives - The ink may contain surfactants, defoamers, preservatives, antifungal agents, rust inhibitors, pH adjusters, etc., as needed.

[0042] --Surfactants-- Any of the following surfactants can be used: silicone-based surfactants, fluorine-based surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants. There are no particular restrictions on silicone-based surfactants, and they can be appropriately selected according to the purpose. Among them, those that do not decompose even at high pH are preferred. Examples of silicone-based surfactants include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and both-end modified polydimethylsiloxane. Those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group are particularly preferred because they exhibit good properties as aqueous surfactants. In addition, polyether-modified silicone-based surfactants can also be used as silicone-based surfactants, for example, compounds in which a polyalkylene oxide structure is introduced into the Si side chain of dimethylsiloxane.

[0043] Examples of fluorinated surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains, as they exhibit low foaming properties. Examples of perfluoroalkyl sulfonic acid compounds include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate salts. Examples of perfluoroalkyl carboxylic acid compounds include perfluoroalkyl carboxylic acid and perfluoroalkyl carboxylic acid salts. Examples of polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains include sulfate ester salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in their side chains, and salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in their side chains. Examples of counterions for the salts of these fluorinated surfactants include Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2, and NH(CH2CH2OH)3. Examples of amphoteric surfactants include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, and lauryldihydroxyethylbetaine. Examples of nonionic surfactants include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and ethylene oxide adducts of acetylene alcohol. Examples of anionic surfactants include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, and salts of polyoxyethylene alkyl ether sulfate. These can be used individually or in combination of two or more types. There are no particular restrictions on the silicone-based surfactant, and it can be appropriately selected depending on the purpose. Examples include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and both-end modified polydimethylsiloxane. Polyether-modified silicone-based surfactants having a polyoxyethylene group or a polyoxyethylene-polyoxypropylene group as a modifying group are particularly preferred as they exhibit good properties as aqueous surfactants.

[0044] Such surfactants may be synthesized as appropriate, or commercially available products may be used. Commercially available products include, for example, those from BIC Chemie Inc., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd. There are no particular restrictions on the polyether-modified silicone surfactants mentioned above, and they can be appropriately selected depending on the purpose. For example, one example is a polyalkylene oxide structure represented by the general formula (S-1), in which a polyalkylene oxide structure is introduced into the Si side chain of dimethylpolysiloxane.

[0045] [ka]

[0046] (However, in general formula (S-1), m, n, a, and b each independently represent integers, R represents an alkylene group, and R' represents an alkyl group.)

[0047] Commercially available polyether-modified silicone surfactants can be used, such as KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-1906EX (Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (BIC Chemie Co., Ltd.), TSF4440, TSF4452, and TSF4453. As for fluorine-based surfactants, compounds with 2 to 16 carbon atoms substituted with fluorine are preferred, and compounds with 4 to 16 carbon atoms substituted with fluorine are more preferred. Examples of fluorinated surfactants include perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains. Among these, polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains are preferred because they have low foaming properties, and fluorinated surfactants represented by general formulas (F-1) and (F-2) are particularly preferred.

[0048] [ka]

[0049] In the compound represented by the above general formula (F-1), m is preferably an integer between 0 and 10, and n is preferably an integer between 0 and 40, in order to impart water solubility.

[0050] C n F 2n+1- CH2CH(OH)CH2-O-(CH2CH2O) a -Y...General formula (F-2) In the compound represented by the above general formula (F-2), Y is H or C m F 2m+1 m is an integer from 1 to 6, or CH2CH(OH)CH2-C m F2m+1 wherein m is an integer of 4 to 6, or C p H 2p+1 wherein p is an integer of 1 to 19, n is an integer of 1 to 6, and a is an integer of 4 to 14.

[0051] Commercially available products may be used as the fluorine-based surfactant described above. Examples of such commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fluorad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, and FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F-1405, and F-474 (all manufactured by Dainippon Ink and Chemicals, Incorporated); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, and FS-35 (all manufactured by Chemours); FT-110, FT-250, FT-251, FT-400S, FT-150, and FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, and PF-159 (manufactured by Omnova Solutions Inc.), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), and the like. Among these, from the viewpoint that good print quality, particularly color developability, permeability to paper, wettability, and level-dyeing properties are significantly improved, FS-3100, FS-34, and FS-300 manufactured by Chemours, FT-110, FT-250, FT-251, FT-400S, FT-150, and FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omnova Solutions Inc., and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferred.

[0052] There is no particular limitation on the content of the surfactant in the ink, and it can be appropriately selected according to the purpose. From the viewpoint of excellent wettability, ejection stability and improved image quality, the content is preferably 0.001% by mass or more and 5% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less.

[0053] --Antifoaming agent-- There are no particular restrictions on the defoaming agent; examples include silicone-based defoaming agents, polyether-based defoaming agents, and fatty acid ester-based defoaming agents. These may be used individually or in combination of two or more. Among these, silicone-based defoaming agents are preferred due to their superior foam-breaking effect.

[0054] --Preservative and fungicidal agent-- There are no particular restrictions on the preservatives and fungicides used; for example, 1,2-benzisothiazolin-3-one can be used.

[0055] --Rust Inhibitor-- There are no particular restrictions on the rust inhibitors used; examples include acidic sulfites and sodium thiosulfate.

[0056] --pH adjuster-- As for pH adjusting agents, there are no particular restrictions as long as they can adjust the pH to 7 or higher, and examples include amines such as diethanolamine and triethanolamine.

[0057] There are no particular restrictions on the physical properties of the ink, and they can be appropriately selected according to the purpose. For example, it is preferable that the viscosity, surface tension, pH, etc., are within the following ranges.

[0058] <Ink properties> The viscosity of the ink at 25°C is preferably between 3 mPa·s and 30 mPa·s, and more preferably between 5 mPa·s and 25 mPa·s, as this improves print density and character quality and ensures good ejection. Here, viscosity can be measured using, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). Measurement conditions are 25°C, standard cone rotor (1°34'×R24), sample volume of 1.2 mL, rotation speed of 50 rpm, and measurement can be performed in 3 minutes. The surface tension of the ink is preferably 35 mN / m or less, and more preferably 32 mN / m or less, at 25°C, in order to ensure that the ink levels well on the recording medium and shorten the ink drying time. From the viewpoint of preventing corrosion of metal components in contact with the ink, the pH of the ink is preferably 7 to 12, and more preferably 8 to 11.

[0059] <Cleaning solution> The cleaning solution preferably contains a compound having the structure represented by the following structural formula (1), and also contains water, an organic solvent, etc. [ka] The compound represented by structural formula (1) above plays a role in lifting dirt (water-soluble polymer) near the nozzle surface, and may be synthesized as appropriate or a commercially available product may be used. As the aforementioned commercially available product, a commercially available product manufactured by Shin-Etsu Silicone Co., Ltd. can be used.

[0060] The content of the compound represented by structural formula (1) is 0.2% by mass or more and 1.5% by mass or less relative to the cleaning solution, and is preferably 0.8% by mass or more and 1.2% by mass or less from the viewpoint of maintainability. If the content is 0.2% by mass or more, water-soluble polymers adhering to the nozzle surface can be sufficiently wiped away. If the content is 1.5% by mass or less, it will not mix with the ink on the nozzle surface, and dispensing problems can be prevented.

[0061] The cleaning solution may contain a compound that does not have the structure represented by the following structural formula (2) and Si, and has 8 or more carbon atoms. This enhances the effect of lifting dirt (water-soluble polymers) near the nozzle surface. [ka] There are no particular restrictions on the content of the aforementioned compound, and it can be appropriately selected depending on the purpose, but from the viewpoint of maintainability, it is preferable to have a content of 1.0% by mass or more and 10.0% by mass or less. The aforementioned compounds are not particularly limited and can be appropriately selected depending on the purpose. Examples include 2-(2-butoxyethoxy)ethanol and dipropylene glycol monopropyl ether.

[0062] The cleaning solution may include a compound having the structure represented by the following structural formula (2) and not containing Si. This enhances the effect of lifting dirt (water-soluble polymers) near the nozzle surface. [ka] There are no particular restrictions on the content of the aforementioned compound, and it can be appropriately selected depending on the purpose, but from the viewpoint of maintainability, it is preferable that it be 1.0% by mass or more and 6.0% by mass or less. The aforementioned compounds are not particularly limited and can be appropriately selected depending on the purpose. Examples include benzyl alcohol, phenethyl alcohol, and 2-phenoxyethanol.

[0063] <Qualitative and quantitative methods for cleaning solution and ink components> Qualitative and quantitative methods for organic solvents, resins, pigments, and other components contained in the cleaning solution and ink of the present invention include, for example, gas chromatography-mass spectrometry (GC-MS). For example, a measuring device for gas chromatography-mass spectrometry (GC-MS) could be the GCMS-QP2020NX (manufactured by Shimadzu Corporation). The amount of water contained in the ink can be measured by general methods such as quantitative determination of volatile components by gas chromatography-mass spectrometry (GC-MS) or mass fluctuation by simultaneous thermogravimetric and differential thermal analysis (TG-DTA).

[0064] Furthermore, the inkjet recording apparatus of the present invention may also be used as a three-dimensional molding apparatus. The three-dimensional molding apparatus for forming three-dimensional objects in the present invention can employ known configurations and is not particularly limited, but for example, one equipped with ink storage means, supply means, ejection means, drying means, etc., can be used. Three-dimensional objects include three-dimensional objects obtained by applying ink in multiple layers. It also includes molded products obtained by processing a structure on which ink has been applied to a substrate such as a recording medium. Molded products are, for example, obtained by subjecting a recording material or structure formed in the form of a sheet or film to molding processes such as heat stretching or punching, and are suitably used in applications where the surface is decorated before molding, such as meters and control panels for automobiles, office automation equipment, electrical and electronic equipment, cameras, etc.

[0065] <Recording medium> There are no particular restrictions on the recording medium; any hygroscopic material such as plain paper, glossy paper, specialty paper, or cloth can be used. The recording medium is not limited to those commonly used as recording media; building materials such as wallpaper, flooring, and tiles, fabrics for clothing such as T-shirts, textiles, leather, etc., can be used as appropriate. Furthermore, by adjusting the configuration of the transport path for the recording medium, ceramics, glass, metal, etc., can also be used. Furthermore, you can freely choose between continuous sheets and cut sheets.

[0066] <Records> The ink recording material of the present invention has an image formed on a recording medium using the ink of the present invention. The data can be recorded and produced as a record using an inkjet recording device and an inkjet recording method.

[0067] <How to use the ink> Furthermore, the method of using ink is not limited to inkjet recording and can be used in a wide range of ways. In addition to inkjet recording, other methods such as blade coating, gravure coating, bar coating, roll coating, dip coating, curtain coating, slide coating, die coating, and spray coating can also be used. The ink of the present invention has no particular limitations on its use and can be appropriately selected according to the purpose. For example, it can be applied to printed materials, paints, coatings, and undercoats. Furthermore, it can be used not only as an ink to form two-dimensional characters and images, but also as a material for forming three-dimensional objects (three-dimensional sculptures).

[0068] In the terminology used in this invention, image formation, recording, printing, and the like are all synonymous. Recording medium, media, and printed material are all synonymous. [Examples]

[0069] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The units for the content of various materials used in the examples and comparative examples are "mass%". In addition, the numerical values ​​indicating the content of pigment dispersions and resins all represent the solid content.

[0070] <Ink preparation examples 1-24> Based on the ink compositions shown in Tables 1 and 2 below, each material was mixed and stirred, filtered using a 5 μm average pore size filter (Sartorius Minisart), and then filtered again using a 0.5 μm average pore size polypropylene filter to prepare inks 1 to 24.

[0071] [Table 1]

[0072] [Table 2]

[0073] <Examples of solution preparation 1-38> Based on the ink compositions shown in Tables 3-6 below, each material was mixed and stirred to prepare cleaning solutions 1-38.

[0074] [Table 3]

[0075] [Table 4]

[0076] [Table 5]

[0077] [Table 6]

[0078] The following materials were used in the preparation of the aforementioned ink and cleaning solution. <Pigment dispersion> • CAB-O-JET 400 (manufactured by Cabot)

[0079] <Water-soluble polymer> • Polyethylene glycol 600 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., number average molecular weight 560-640) • Polyethylene glycol 1000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., number average molecular weight 900-1,100) • Polyethylene glycol 2000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., number average molecular weight 1800-2200) • Polyethylene glycol 4000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., number average molecular weight 2700-3300)

[0080] <organic solvents> Glycerin (manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 290°C) • N-butyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 275℃)

[0081] <Surfactants> • Olefin E1004 (manufactured by Nisshin Chemical Industry Co., Ltd.)

[0082] <Compounds having the structure of structural formula (1)> • KF353 (manufactured by Shin-Etsu Silicone Co., Ltd.) • KF354L (manufactured by Shin-Etsu Silicone Co., Ltd.) • KF945 (manufactured by Shin-Etsu Silicone Co., Ltd.)

[0083] <A compound that does not have the structure represented by structural formula (2) and Si, and has 8 or more carbon atoms> • 2-(2-butoxyethoxy)ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 8 carbon atoms) • Dipropylene glycol monopropyl ether (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 9 carbon atoms) <Compounds having the structure represented by structural formula (2) and lacking Si> • Benzyl alcohol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • Phenethyl alcohol (manufactured by Tokyo Chemical Industry Co., Ltd.) • 2-Phenoxyethanol (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0084] (Examples 1-48 and Comparative Examples 1-15) Inks 1-24 and cleaning solutions 1-38 were loaded into the inkjet recording device shown in Figure 1 in the combinations shown in Tables 7-15 below. The inkjet recording device has a liquid ejection head 1, a blade member 2, and a jetting mechanism 3. The NPi Form NEXT-IJ dispenses solid images at a resolution of 600dpi x 600dpi from the liquid dispensing head. <70> Printing was performed on paper (manufactured by Nippon Paper Industries Co., Ltd., basis weight 81.4 gsm), and ejection was carried out from all nozzles for 1.5 hours. Afterward, it was left standing for 4 hours. Maintenance operations (spraying, pressurizing, and wiping processes) were then performed. In Comparative Example 14, the inkjet recording device shown in Figure 3 was used, and in Comparative Example 15, the inkjet recording device shown in Figure 4 was used. Figure 3 is a schematic diagram showing the inkjet recording device used in Comparative Example 14 and its maintenance operation. This recording device has a liquid ejection head 5, a blade member 6, and a spraying mechanism 7. First, the ink is pressurized in a pressurization step to form droplets of ink on the nozzle surface of the liquid ejection head 5. Then, the cleaning liquid is sprayed onto the nozzle surface in a spraying step. After that, the nozzle surface that has been in contact with the cleaning liquid is wiped with the blade member 6 in a wiping step. Figure 4 is a schematic diagram showing the inkjet recording device used in Comparative Example 15 and its maintenance operation. This recording device has a liquid ejection head 9 and a blade member 10. First, the ink is pressurized in a pressurization step to form droplets of ink on the nozzle surface of the liquid ejection head 9. Then, in a wiping step, the nozzle surface, which has been in contact with the cleaning liquid and sprayed, is wiped by the blade member 10.

[0085] In each example and comparative example, image density and maintainability were evaluated based on the following methods. The evaluation results are shown in Tables 7 to 15 below.

[0086] <Image density> In Examples 1-48 and Comparative Examples 1-15, the solid areas of the obtained images were measured using a reflective color spectrophotometer (X-Rite), and the image density was evaluated based on the following criteria. A score of "A" or higher indicates a range suitable for practical use. [Evaluation Criteria] AA: Image density 1.2 or higher A: Image density 1.1 or higher and less than 1.2 B: Image density between 1.0 and less than 1.1 C: Image density less than 1.0

[0087] <Maintainability> In Examples 1-48 and Comparative Examples 1-15, maintenance operations (injection, pressurization, and wiping) were performed, and the number of maintenance operations required for all nozzles to be ready for discharge was determined. Based on the number of maintenance operations, the maintainability was evaluated according to the following criteria. A rating of "B" or higher indicates a range that is actually usable. [Evaluation Criteria] AA: All nozzles dispense during a single maintenance operation. A: All nozzles will dispense after two to three maintenance operations. B: All nozzles dispense after 3 to 5 maintenance operations. C: All nozzles dispense after 5 to 7 maintenance operations. D: All nozzles will dispense after 7 or more maintenance operations.

[0088] [Table 7]

[0089] [Table 8]

[0090] [Table 9]

[0091] [Table 10]

[0092] [Table 11]

[0093] [Table 12]

[0094] [Table 13]

[0095] Examples 1 to 48 show that, using the apparatus shown in Figure 1, image density and maintainability can be achieved when the content of a water-soluble polymer with a number average molecular weight Mn of 560 to 3,300 is 11.0% to 30.0% by mass relative to the ink, and the content of a compound having the structure represented by structural formula (1) is 0.2% to 1.5% by mass relative to the cleaning solution. A comparison of Examples 1 to 16 shows that image density is better when the number-average molecular weight (Mn) of the water-soluble polymer is 900 or higher. Furthermore, it is found that maintainability is better when the number-average molecular weight (Mn) of the water-soluble polymer is 2,200 or lower. A comparison between Examples 6 and 7 and Examples 5 and 8, and between Examples 10 and 11 and Examples 9 and 12, reveals that image density and maintainability are better balanced when the water-soluble polymer content is between 15.0% by mass and 20.0% by mass. A comparison of Examples 6 and 17-23 with Examples 24-32 and 42-44 with Examples 22-30 and 40-44 reveals that maintainability is better when the content of a compound with the structure represented by structural formula (2), which does not contain Si and has 8 or more carbon atoms, is between 1.0% by mass and 10.0% by mass relative to the cleaning solution. A comparison of Examples 6, 17-23 and 33-44 reveals that maintainability is better when the content of a compound having the structure represented by structural formula (2) and lacking Si is 1.0% by mass or more and 6.0% by mass or less relative to the cleaning solution. A comparison of Examples 6, 46, and 47 with Examples 45 and 48 reveals that maintainability is better when the content of the compound having the structure represented by structural formula (1) is 0.8% by mass or more and 1.2% by mass or less relative to the cleaning solution. A comparison of Examples 1-48 with Comparative Examples 1-8 reveals that when the water-soluble polymer content is less than 11.0% by mass, the image density falls outside the acceptable range. Furthermore, when the water-soluble polymer content exceeds 30.0% by mass, the maintainability falls outside the acceptable range. A comparison of Examples 1-48 and Comparative Examples 9-13 reveals that maintainability falls outside the acceptable range when the content of the compound having the structure represented by structural formula (1) is not 0.2% by mass or more and 1.5% by mass or less relative to the cleaning solution. A comparison of Examples 1-48 and Comparative Example 14 reveals that in a configuration where ink is pressurized to form droplets on the nozzle surface before the cleaning solution is sprayed, the maintainability falls outside the acceptable range. A comparison of Examples 1-48 and Comparative Example 15 reveals that in a configuration where ink is pressurized to form droplets on the nozzle surface and then wiped away by a blade member, the maintainability falls outside the acceptable range.

[0096] Examples of the present invention are as follows: <1> An ink containing a water-soluble polymer having a number-average molecular weight Mn of 560 or more and 3,300 or less, A liquid dispensing head having a nozzle surface on which a nozzle for dispensing the aforementioned ink is provided, A washing solution containing a compound having the structure represented by the following structural formula (1), [ka] A spraying member that sprays the cleaning liquid onto the nozzle surface, A pressurizing member that pressurizes the ink to form droplets of the ink on the nozzle surface, It comprises a blade member that contacts the nozzle surface and wipes the nozzle surface from which the cleaning liquid has been sprayed, The content of the water-soluble polymer is 11.0% by mass or more and 30.0% by mass or less relative to the ink. The inkjet recording apparatus is characterized in that the content of the compound having the structure represented by the structural formula (1) is 0.2% by mass or more and 1.5% by mass or less relative to the cleaning solution. <2> The aforementioned cleaning solution contains a compound that has a structure represented by the following structural formula (2) and does not contain Si, and has 8 or more carbon atoms. The content of the compound is 1.0% by mass or more and 10.0% by mass or less relative to the washing solution. <1> This is the inkjet recording device described in [reference]. [ka] <3> The cleaning solution contains a compound having a structure represented by the following structural formula (2) and not containing Si, The content of a compound having the structure represented by the structural formula (2) and not containing Si is 1.0% by mass or less and 6.0% by mass or less relative to the washing solution. <1> from <2> It is an inkjet recording device as described in any of the following. [ka] <4> The content of the compound having the structure represented by the structural formula (1) is 0.8% by mass or more and 1.2% by mass or less relative to the washing solution. <1> from <2> It is an inkjet recording device as described in any of the following. <5> The number-average molecular weight Mn of the water-soluble polymer is 900 or more and 2,200 or less. <1> from <2> It is an inkjet recording device as described in any of the following. <6> The content of the water-soluble polymer is 15.0% by mass or more and 20.0% by mass or less relative to the ink. <1> from <2> It is a recording device as described in any of the following. <7> An ink ejection process in which an ink containing a water-soluble polymer having a number-average molecular weight Mn of 560 or more and 3,300 or less is ejected from the nozzle surface of a liquid ejection head, A spraying step in which a cleaning solution containing a compound having the structure of the following structural formula (1) is sprayed onto the nozzle surface, A pressurization step involves pressurizing the ink to form droplets of the ink on the nozzle surface, The process includes a wiping step in which the nozzle surface, which has been in contact with the nozzle surface and sprayed with the cleaning liquid, is wiped with a blade member, The content of the water-soluble polymer is 11.0% by mass or more and 30.0% by mass or less relative to the ink. The inkjet recording method is characterized in that the content of the compound having the structure of structural formula (1) is 0.2% by mass or more and 1.5% by mass or less relative to the cleaning solution.

[0097] The aforementioned <1> from <6> An inkjet recording device as described in any of the above, and the <7> The inkjet recording apparatus described above can solve the aforementioned problems of the conventional method and achieve the objectives of the present invention. [Explanation of Symbols]

[0098] 1. Liquid dispensing head 2 Blade members 3 Injection mechanism 4. Wiping mechanism 5. Liquid dispensing head 6 Blade members 7 Injection mechanism 8. Wiping mechanism 9 Liquid dispensing head 10 Blade members 11. Wiping mechanism 12 Paper feeder 13. Winding device 14 Liquid dispensing head 15 IR heater 16. Hot air device 17 Exhaust duct P Continuous paper [Prior art documents] [Patent Documents]

[0099] [Patent Document 1] Japanese Patent Publication No. 2015-052084 [Patent Document 2] Japanese Patent Publication No. 2021-075015

Claims

1. An ink ejection process in which an ink containing a water-soluble polymer having a number-average molecular weight Mn of 560 or more and 3,300 or less is ejected from the nozzle surface of a liquid ejection head, A spraying step in which a cleaning solution containing a compound having the structure of the following structural formula (1) is sprayed onto the nozzle surface, A pressurization step involves pressurizing the ink to form droplets of the ink on the nozzle surface, The process includes a wiping step in which the nozzle surface, which has been in contact with the nozzle surface and sprayed with the cleaning liquid to form droplets of ink, is wiped with a blade member. The injection step is performed before the pressurization step. The content of the water-soluble polymer is 11.0% by mass or more and 30.0% by mass or less relative to the ink. An inkjet recording method characterized in that the content of the compound having the structure of structural formula (1) is 0.2% by mass or more and 1.5% by mass or less relative to the cleaning solution. 【Chemistry 1】

2. The cleaning solution contains a compound that has a structure represented by the following structural formula (2) and does not have Si, and has 8 or more carbon atoms. The inkjet recording method according to claim 1, wherein the content of a compound having a structure represented by the structural formula (2) and no Si, and having 8 or more carbon atoms, is 1.0% by mass or more and 10.0% by mass or less relative to the cleaning solution. 【Chemistry 2】

3. The cleaning solution contains a compound having the structure represented by the following structural formula (2) and not containing Si, The inkjet recording method according to any one of claims 1 to 2, wherein the content of a compound having the structure represented by the structural formula (2) and not containing Si is 1.0% by mass to 6.0% by mass or less relative to the cleaning solution. 【Transformation 3】

4. The inkjet recording method according to any one of claims 1 to 2, wherein the content of the compound having the structure represented by the structural formula (1) is 0.8% by mass or more and 1.2% by mass or less relative to the cleaning solution.

5. The inkjet recording method according to any one of claims 1 to 2, wherein the number-average molecular weight Mn of the water-soluble polymer is 900 or more and 2,200 or less.

6. The inkjet recording method according to any one of claims 1 to 2, wherein the content of the water-soluble polymer is 15.0% by mass or more and 20.0% by mass or less relative to the ink.

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