JP2024078940A - Inkjet recording apparatus and inkjet recording method - Google Patents

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

The present invention relates to an inkjet recording device and an inkjet recording method.

Inkjet printers have the advantages of low noise, low running costs, easy color printing, etc., and are widely used as digital signal output devices. As printing substrates used in inkjet printers, absorbent recording media such as plain paper, low absorbent recording media such as coated paper, non-absorbent recording media such as plastic films, etc. are used.
When printing is performed on such a low-absorbency recording medium, there is a problem that the ink (hereinafter, may be referred to as "ink jet composition") cannot spread sufficiently, resulting in a decrease in image quality.
It is known that when the ink-jet composition contains a water-soluble polymer, the ink-jet composition spreads better and image quality is improved.

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, each 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 abrasion resistance and flexibility (see, for example, Patent Document 1).

As an inkjet recording device using the inkjet composition, for example, an inkjet recording device has been proposed that is characterized by comprising a recording head that ejects ink from an ejection port, an application means that applies ink to the ejection port formation surface of the recording head, a capping unit that caps the ejection port of the recording head, a suction means that applies a suction pressure to the recording head capped by the capping unit to perform suction, and a control means that, when suction is performed by the suction means, controls the application means to apply ink to the ejection port formation surface before the suction operation.

The present invention provides an inkjet recording device that has good maintainability of the recording head even when using ink containing a water-soluble polymer, and can form images with excellent image density.

前記ノズル面に対して前記洗浄液を噴射する噴射部材と、
前記インクを加圧して前記ノズル面上に前記インクの液滴を形成する加圧部材と、
前記ノズル面に接触して前記洗浄液が噴射された前記ノズル面を払拭するブレード部材と、を有し、
前記水溶性高分子の含有量が、前記インクに対して１１．０質量％以上３０．０質量%以下であり、
前記構造式（１）の構造を有する化合物の含有量が、前記洗浄液に対して０．２質量％以上１．５質量％以下である。 The inkjet recording apparatus of the present invention as a means for solving the above 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 ejection head having a nozzle surface provided with nozzles for ejecting the ink;
A cleaning solution containing a compound having a structure represented by the following structural formula (1):

an ejection member that ejects the cleaning liquid onto the nozzle surface;
a pressure member that pressurizes the ink to form droplets of the ink on the nozzle surface;
a blade member that comes into contact with the nozzle surface and wipes the nozzle surface onto 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 with respect to the ink,
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 with respect to the cleaning liquid.

The present invention provides an inkjet recording device that has good maintainability of the recording head even when using ink containing a water-soluble polymer, and can form images with excellent image density.

FIG. 1 is a schematic diagram showing an example of an ink jet recording apparatus according to the present invention and its maintenance operation. FIG. 2 is a schematic diagram showing an example of an inkjet recording apparatus according to the present invention. FIG. 3 is a schematic diagram showing an example of an inkjet recording apparatus used in Comparative Example 14 and its maintenance operation. FIG. 4 is a schematic diagram showing an example of an inkjet recording apparatus used in Comparative Example 15 and its maintenance operation.

(Inkjet recording apparatus and inkjet recording method)
The inkjet recording apparatus of the present invention comprises ink, a liquid ejection head, a cleaning liquid, an ejection member, a pressure member, and a blade member, and may comprise other members as necessary.
The ink jet recording method of the present invention comprises an ink ejection step, a jetting step, a pressurizing step, and a wiping step, and may comprise other steps as necessary.
The recording apparatus of the present invention may be called an image forming apparatus, an inkjet recording apparatus, an inkjet printer, a modeling apparatus, or the like.

It has been reported that the ink-jet ink composition described in Patent Document 1, which does not contain a water-soluble polymer, deteriorates the image quality when printed on high-quality paper, causing uneven density and streaks.
In the inkjet recording apparatus described in JP-A-2003-133999, the resin adhering to the nozzle surface cannot be sufficiently removed by only applying ink.

The inventors conducted intensive research and found that a liquid ejection head having a nozzle surface provided with nozzles for ejecting the ink includes an ink containing a water-soluble polymer having a number average molecular weight Mn of 560 to 3,300, a cleaning liquid containing a compound having a structure represented by the following structural formula (1), an ejection member for ejecting the cleaning liquid against the nozzle surface, a pressurizing member for pressurizing the ink to form droplets of the ink on the nozzle surface, and a blade member for contacting the nozzle surface and wiping the nozzle surface onto which the cleaning liquid has been ejected, and that the content of the water-soluble polymer is 11.0% by mass to 30.0% by mass with respect to the ink, and the content of the compound having the structure of structural formula (1) is 0.2% by mass to 1.5% by mass with respect to the cleaning liquid, thereby making it possible to form an image with excellent image density and to maintain the recording head even with an ink containing a water-soluble polymer.

The recording device according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiment shown below, and can be modified within the scope of what a person skilled in the art can imagine, including other embodiments, additions, modifications, deletions, etc., and any aspect is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

Figure 1 is a schematic diagram showing one embodiment of an inkjet recording device and an example of its maintenance operation. This embodiment has, for example, a liquid ejection head 1, a blade member 2, and an ejection member 3.

As shown in FIG. 1, the ejection step involves ejecting cleaning liquid onto the nozzle surface of the liquid ejection head 1. By performing the ejection step before the pressurization step, ink stains near the nozzle surface can be lifted. The ejection step can be performed by an ejection member 3.

In the pressurizing step, as shown in FIG. 1, the 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 dirt can be removed. The pressurizing step can be performed by a pressurizing member.

As shown in FIG. 1, the wiping process involves contacting a blade member 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 process, the blade member can remove ink stains on the nozzle surface together with the cleaning liquid, making the nozzles ready for ejection. The wiping process can be performed by a blade member 2.

Figure 2 is a conceptual diagram showing the recording device, and the transport means includes a paper feeder 12, a winding device 13, and a roller 18. The recording medium (continuous paper P) is transported between the paper feeder 12 and the winding device 13, comes into contact with roller 18, which is a transport member, and is transported in the direction of the arrow. Note that only one roller 7 is given a reference number, and the reference numbers for the others are omitted. Furthermore, the configuration of roller 18 is not limited to that shown in the figure, and can be changed as appropriate, for example, the number and arrangement can be changed as appropriate.

The liquid ejection head is not particularly limited and can be appropriately selected depending on the purpose. For example, an inkjet head can be used.
In FIG. 2, an inkjet head 14 is used to eject ink onto a recording medium.

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

The exhaust means exhausts the air inside the housing. In this embodiment, the exhaust means includes, for example, an exhaust duct 17 and a fan. The exhaust duct 17 includes an intake port for sucking in the air inside the housing and an exhaust port for exhausting the air.

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

The arrangement of the IR heater 15 and the exhaust duct 17 can be changed as appropriate. It is preferable that a path along which the recording medium is transported before reaching the IR heater 15 exists between the IR heater 15 and the suction port of the exhaust duct 17. 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.
In addition, the phrase "between the IR heater 15 and the suction port of the exhaust duct 17" can also be referred to as being on a straight line connecting the IR heater 15 and the exhaust duct 17, and it is taken into consideration whether a transport path for the recording medium exists on such a straight line.

<Ink>
The organic solvent, water, coloring material, resin, additives, etc. used in the ink will be described below.
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 coloring material, an organic solvent and water, and optionally other components.

- Water-soluble polymers -
The water-soluble polymer is a molecule having a number average molecular weight Mn of 560 or more.
The number average molecular weight Mn of the water-soluble polymer is preferably from 560 to 3,300 in terms of image density and maintainability, more preferably from 900 to 3,300 in terms of image density, and particularly preferably from 900 to 2,200 in terms of maintainability.

The method for measuring the number average molecular weight Mn is not particularly limited and can be appropriately selected depending on the purpose, and can be measured, for example, by GPC (Gel Permeation Chromatography) etc. Specific measurement conditions are as follows.
[Measurement condition]
Apparatus: GPC-8020 (manufactured by Tosoh Corporation)
Column: TSK G2000HXL and G4000HXL (manufactured by Tosoh Corporation)
Temperature: 40°C
Solvent: THF (tetrahydrofuran)
Flow rate: 1.0 mL/min

The content of the water-soluble polymer is 11.0% by mass or more and 30.0% by mass or less with respect 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.

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

- Organic solvents -
The organic solvent used in the present invention is not particularly limited, and any water-soluble organic solvent can be used. Examples of the organic solvent 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.

Specific examples of polyhydric alcohols include 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 of such glycerin include 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, and petriol.
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 the 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 the amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide.
Examples of the amines include monoethanolamine, diethanolamine, and triethylamine.
Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, and thiodiethanol.
Other organic solvents include propylene carbonate, ethylene carbonate, and the like.
It is preferable to use an organic solvent having a boiling point of 250° C. or less, since it not only functions as a wetting agent but also provides good drying properties.

-water-
The water content is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of the drying property and ejection reliability of the ink, however, it is preferably from 10% by mass to 90% by mass, and more preferably from 20% by mass to 80% by mass.

- Coloring materials -
The coloring material is not particularly limited and can be appropriately selected depending on the purpose. Examples of the coloring material include pigments and dyes.
The pigment is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include inorganic pigments, organic pigments, etc. These pigments may be used alone or in combination of two or more. Mixed crystals may also be used as the pigment.
Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver pigments, and metallic pigments.
As inorganic pigments, titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, as well as carbon black produced by known methods such as the contact method, furnace method, and thermal method can be used.
As organic pigments, 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, aniline black, etc. can be used. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.

Specific examples of pigments for black colors include carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper, iron (C.I. Pigment Black 11), and titanium oxide; and organic pigments such as aniline black (C.I. Pigment Black 1).
Further, for color, C.I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 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 (Red ochre), 1 04, 105, 106, 108 (Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38, C.I. Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3, 15:4 (Phthalocyanine Blue), 16, 17:1, 56, 60, 63, C.I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. One type of dye may be used alone, or two or more types may be used in combination.

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

The content of colorant 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 viewpoints of improving image density, good fixation property and ejection stability.

Methods for dispersing a pigment to obtain an ink include a method in which a hydrophilic functional group is introduced into the pigment to make it a self-dispersing pigment, a method in which the surface of the pigment is coated with a resin and then dispersed, and a method in which a dispersant is used to disperse the pigment.
As a method for making a pigment self-dispersible by introducing a hydrophilic functional group into the pigment, for example, a method for making the pigment dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to the pigment (e.g., carbon) can be mentioned.
A method of dispersing a pigment by coating its surface with a resin includes a method of encapsulating the pigment in a microcapsule to make 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 a "resin-coated pigment"). When dispersing a pigment by coating its surface with a resin, it is not necessary for all of the pigments blended in the ink to be coated with a resin, and uncoated or partially coated pigments may be dispersed in the ink as long as the effect of the present invention is not impaired.

Examples of the method for dispersing using a dispersant include a method for dispersing using a known low molecular weight dispersant or a high molecular weight dispersant, typified by a surfactant.
As the dispersant, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. can be used depending on the pigment.
As the dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Oil Co., Ltd. and sodium naphthalenesulfonate formalin condensate can also be suitably used.
The dispersants may be used alone or in combination of two or more.

-resin-
The type of resin contained in the ink is not particularly limited and can be appropriately selected depending on the purpose. Examples of the resin 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 of these resins may be used. The resin particles may be dispersed in water as a dispersion medium in a resin emulsion state, and mixed with materials such as coloring materials and organic solvents to obtain an ink. The resin particles may be appropriately synthesized or may be commercially available. These may be used alone or in combination of two or more types of resin particles.

There are no particular limitations on the volume average particle size of the resin particles and they can be selected appropriately depending on the purpose, but in order to obtain good fixation and high image hardness, a volume average particle size of 10 nm or more and 1,000 nm or less is preferable, a volume average particle size of 10 nm or more and 200 nm or less is more preferable, and a volume average particle size of 10 nm or more and 100 nm or less is particularly preferable.

The volume average particle size can be measured, for example, using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).
The resin content is not particularly limited and can be appropriately selected depending on the purpose.

There are no particular restrictions on the particle size of the solid content in the ink, and it can be selected appropriately depending on the purpose. In order to improve image quality such as ejection stability and image density, the maximum frequency of the particle size of the solid content in the ink, calculated in terms of the maximum number, is preferably 20 nm or more and 1,000 nm or less, and more preferably 20 nm or more and 150 nm or less. The solid content includes 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.).

-Additive-
If necessary, surfactants, antifoaming agents, antiseptic and antifungal agents, rust inhibitors, pH adjusters, and the like may be added to the ink.

--Surfactants--
As the surfactant, any of silicone-based surfactants, fluorine-based surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used.
The silicone surfactant is not particularly limited and can be appropriately selected according to the purpose. Among them, those that do not decompose even at high pH are preferable. Examples of silicone surfactants include side chain modified polydimethylsiloxane, both end modified polydimethylsiloxane, one end modified polydimethylsiloxane, and both end modified polydimethylsiloxane of side chain. Those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modified group are particularly preferable because they show good properties as an aqueous surfactant. In addition, polyether modified silicone surfactants can also be used as silicone surfactants, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylsiloxane.

As the fluorine-based surfactant, for example, perfluoroalkyl sulfonic acid compound, perfluoroalkyl carboxylic acid compound, perfluoroalkyl phosphate compound, perfluoroalkyl ethylene oxide adduct and polyoxyalkylene ether polymer compound having perfluoroalkyl ether group in the side chain are particularly preferred because they have low foaming properties.As the perfluoroalkyl sulfonic acid compound, for example, perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, etc. can be mentioned.As the perfluoroalkyl carboxylic acid compound, for example, perfluoroalkyl carboxylic acid, perfluoroalkyl carboxylate, etc. can be mentioned.As the polyoxyalkylene ether polymer compound having perfluoroalkyl ether group in the side chain, for example, sulfate ester salt of polyoxyalkylene ether polymer having perfluoroalkyl ether group in the side chain, salt of polyoxyalkylene ether polymer having perfluoroalkyl ether group in the side chain, etc. can be mentioned. Examples _of counter ions _of the salts in these fluorosurfactants include Li, Na, K _{, NH4} , _NH3CH2CH2OH , _{NH2 ( CH2CH2OH} ) ₂ , and NH( _CH2CH2OH ) ₃ .
Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
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 the anionic surfactant include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, and polyoxyethylene alkyl ether sulfates.
These may be used alone or in combination of two or more.
The silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the silicone surfactant include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and both-end side-chain modified polydimethylsiloxane. Polyether-modified silicone surfactants having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as the modifying group are particularly preferred because they exhibit good properties as aqueous surfactants.

Such surfactants may be synthesized appropriately or may be commercially available products, such as those available from BYK-Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.
The polyether-modified silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be a surfactant represented by the general formula (S-1) in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylpolysiloxane.

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

As the polyether-modified silicone surfactant, commercially available products can be used, and examples thereof include KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-1906EX (Nihon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Dow Corning Toray Silicone Co., Ltd.), BYK-33, BYK-387 (BYK-Chemie Co., Ltd.), TSF4440, TSF4452, and TSF4453.
As the fluorine-based surfactant, a compound having 2 to 16 fluorine-substituted carbon atoms is preferred, and a compound having 4 to 16 fluorine-substituted carbon atoms is more preferred.
Examples of the fluorine-based surfactant include perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group on the side chain, etc. Among these, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group on the side chain are preferred because they have low foaming properties, and the fluorine-based surfactants represented by the general formulas (F-1) and (F-2) are particularly preferred.

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

C _n F _2n+1- CH ₂ CH(OH)CH ₂ -O-(CH ₂ CH ₂ O) _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 where m is an integer from 1 to 6, or CH ₂ CH(OH)CH ₂ -C _m F _2m+1 where m is an integer from 4 to 6, or C _p H _2p+1 where p is an integer from 1 to 19. n is an integer from 1 to 6. a is an integer from 4 to 14.

As the above-mentioned fluorosurfactant, commercially available products may be used. 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.); Fullard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, and FC-431 (all manufactured by Sumitomo 3M Limited); Megafa F-470, F-1405, F-474 (all manufactured by Dainippon Ink & Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT- 250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), and the like. Among these, preferred are those that have good print quality, particularly color development and paper penetration. In terms of significantly improving permeability, wettability, and dye uniformity, FS-3100, FS-34, and FS-300 manufactured by Chemours Corporation, FT-110, FT-250, FT-251, FT-400S, FT-150, and FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omnova, and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferred.

The content of the surfactant in the ink is not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of excellent wettability, ejection stability, and improved image quality, it 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.

--Antifoaming agent--
The defoaming agent is not particularly limited, and examples thereof include silicone-based defoaming agents, polyether-based defoaming agents, and fatty acid ester-based defoaming agents. These may be used alone or in combination of two or more. Among these, silicone-based defoaming agents are preferred because of their excellent foam breaking effect.

--Anti-septic and anti-fungal agent--
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

--anti-rust--
The rust inhibitor is not particularly limited, and examples thereof include acid sulfite and sodium thiosulfate.

--pH adjuster--
There are no particular limitations on the pH adjuster, so long as it is capable of adjusting the pH to 7 or higher, and examples of the pH adjuster include amines such as diethanolamine and triethanolamine.

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

<Ink properties>
The viscosity of the ink at 25°C is preferably 3 mPa·s or more and 30 mPa·s or less, and more preferably 5 mPa·s or more and 25 mPa·s or less, in terms of improving the print density and character quality and obtaining good ejection properties. Here, the viscosity can be measured using, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). The measurement conditions are 25°C, a standard cone rotor (1°34'×R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 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 is appropriately leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably from 7 to 12, and more preferably from 8 to 11, from the viewpoint of preventing corrosion of metal members that come into contact with the ink.

<Cleaning solution>
The cleaning liquid preferably contains a compound having a structure represented by the following structural formula (1) and contains water, an organic solvent, and the like.
The compound represented by the structural formula (1) plays a role in lifting dirt (water-soluble polymer) in the vicinity of the nozzle surface, and may be an appropriately synthesized compound or a commercially available product.
As the commercially available product, a commercially available product manufactured by Shin-Etsu Silicone Co., Ltd. can be used.

The content of the compound represented by the structural formula (1) is 0.2% by mass or more and 1.5% by mass or less with respect to the cleaning liquid, and from the viewpoint of maintainability, 0.8% by mass or more and 1.2% by mass or less is preferable. When the content is 0.2% by mass or more, the water-soluble polymer adhered to the nozzle surface can be sufficiently wiped off. When the content is 1.5% by mass or less, the compound does not mix with the ink on the nozzle surface, and ejection defects can be prevented.

The cleaning liquid may contain a compound having a structure represented by the following structural formula (2), no Si, and 8 or more carbon atoms. This enhances the effect of lifting off dirt (water-soluble polymer) near the nozzle surface.
The content of the compound is not particularly limited and may be appropriately selected depending on the purpose, but is preferably from 1.0% by mass to 10.0% by mass from the viewpoint of maintainability.
The compound is not particularly limited and can be appropriately selected depending on the purpose. Examples of the compound include 2-(2-butoxyethoxy)ethanol and dipropylene glycol monopropyl ether.

The cleaning liquid may contain a compound having a structure represented by the following structural formula (2) and not containing Si. This enhances the effect of lifting off dirt (water-soluble polymer) near the nozzle surface.
The content of the compound is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 1.0% by mass or more and 6.0% by mass or less from the viewpoint of maintainability.
The compound is not particularly limited and can be appropriately selected depending on the purpose. Examples of the compound include benzyl alcohol, phenethyl alcohol, and 2-phenoxyethanol.

<Qualitative and quantitative analysis of cleaning solution and ink components>
Examples of the qualitative and quantitative methods for the organic solvent, resin, pigment, and other components contained in the cleaning solution and ink of the present invention include gas chromatography mass spectrometry (GC-MS). For example, an example of a measuring device using gas chromatography mass spectrometry (GC-MS) is GCMS-QP2020NX (manufactured by Shimadzu Corporation). The amount of water contained in the ink can be measured by general methods such as quantifying the volatile components using gas chromatography mass spectrometry (GC-MS) or measuring mass fluctuations using thermogravimetry-differential thermal analysis (TG-DTA).

The inkjet recording device of the present invention may be used as a three-dimensional modeling device. The three-dimensional modeling device for forming a three-dimensional object in the present invention may adopt a known configuration, and is not particularly limited, but may be, for example, one equipped with an ink storage means, supply means, discharge means, drying means, etc. Three-dimensional objects include three-dimensional objects obtained by applying ink in layers. Also included are molded products obtained by processing a structure on which ink has been applied onto a substrate such as a recording medium. Molded products are, for example, recorded materials or structures formed in a sheet or film form that have been molded by heat stretching, punching, etc., and are preferably used for applications in which the surface is molded after decoration, such as meters and operation panel of automobiles, office automation equipment, electric and electronic equipment, cameras, etc.

<Recording media>
There are no particular limitations on the recording medium, and any hygroscopic material such as plain paper, glossy paper, special paper, or cloth can be used.
The recording medium is not limited to those generally used as recording media, and may be wallpaper, flooring, building materials such as tiles, cloth for clothing such as T-shirts, textiles, leather, etc. Ceramics, glass, metals, etc. may also be used by adjusting the configuration of the path for conveying the recording medium.
In addition, cut paper can be freely selected in addition to continuous paper.

<Recordings>
The ink recorded matter of the present invention comprises an image formed on a recording medium using the ink of the present invention.
A recorded matter can be obtained by recording using an inkjet recording apparatus and an inkjet recording method.

<How to use the ink>
The ink can be used in a wide variety of ways, including, but not limited to, inkjet recording, blade coating, gravure coating, bar coating, roll coating, dip coating, curtain coating, slide coating, die coating, and spray coating.
The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose, and can be applied to, for example, printed matter, paint, coating material, undercoat, etc. Furthermore, the ink can be used not only as an ink for forming two-dimensional characters and images, but also as a material for three-dimensional modeling for forming three-dimensional images (three-dimensional objects).

In the terminology of this invention, image formation, recording, printing, printing, etc. are all synonymous. Recording medium, media, and printed material are all synonymous.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples. The units of content of various materials used in the examples and comparative examples are "mass %". The values showing the content of pigment dispersion and resin both represent the solid content.

<Ink Preparation Examples 1 to 24>
Inks 1 to 24 were prepared by mixing and stirring each material based on the ink composition shown in Tables 1 and 2 below, filtering the mixture through a filter having an average pore size of 5 μm (Minisart, manufactured by Sartorius), and then filtering the mixture through a polypropylene filter having an average pore size of 0.5 μm.

<Solution Preparation Examples 1 to 38>
Based on the ink compositions shown in Tables 3 to 6 below, the materials were mixed and stirred to prepare cleaning solutions 1 to 38.

The materials used in the preparation of the ink and cleaning solution were as follows:
<Pigment Dispersion>
・CAB-O-JET 400 (manufactured by Cabot Corporation)

<Water-soluble polymer>
Polyethylene glycol 600 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., number average molecular weight 560 to 640)
Polyethylene glycol 1000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., number average molecular weight 900 to 1,100)
Polyethylene glycol 2000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., number average molecular weight 1800 to 2,200)
Polyethylene glycol 4000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., number average molecular weight 2700 to 3,300)

<Organic solvent>
Glycerin (manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 290°C)
N-Butyldiethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 275°C)

<Surfactant>
Olefin E1004 (manufactured by Nissin Chemical Industry Co., Ltd.)

<Compound having the structure of structural formula (1)>
・KF353 (manufactured by Shin-Etsu Silicone Co., Ltd.)
・KF354L (Shin-Etsu Silicone Co., Ltd.)
・KF945 (manufactured by Shin-Etsu Silicone Co., Ltd.)

<Compound having a structure represented by structural formula (2), no Si, and having 8 or more carbon atoms>
2-(2-butoxyethoxy)ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, carbon number 8)
Dipropylene glycol monopropyl ether (manufactured by Fujifilm Wako Pure Chemical Industries, carbon number 9)
<Compound having a structure represented by structural formula (2) and not having Si>
・Benzyl alcohol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
- Phenethyl alcohol (Tokyo Chemical Industry Co., Ltd.)
・2-phenoxyethanol (Tokyo Chemical Industry Co., Ltd.)

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

For 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.

<Image Density>
In Examples 1 to 48 and Comparative Examples 1 to 15, the solid areas of the images obtained were measured using a reflective color spectrodensitometer (manufactured by X-Rite Corporation) to measure the image density, and evaluated based on the following criteria. Note that "A" or higher is within the range of practical use.
[Evaluation criteria]
AA: Image density 1.2 or more A: Image density 1.1 or more and less than 1.2 B: Image density 1.0 or more and less than 1.1 C: Image density less than 1.0

<Maintenance>
In Examples 1 to 48 and Comparative Examples 1 to 15, maintenance operations (ejection process, pressurization process, and wiping process) were performed, and the number of maintenance operations required for all nozzles to become capable of ejection was determined. From the number of maintenance operations, maintainability was evaluated based on the following criteria. Note that "B" or higher is within the range of practical use.
[Evaluation criteria]
AA: All nozzles eject after one maintenance operation. A: All nozzles eject after 2 to less than 3 maintenance operations. B: All nozzles eject after 3 to less than 5 maintenance operations. C: All nozzles eject after 5 to less than 7 maintenance operations. D: All nozzles eject after 7 or more maintenance operations.

From Examples 1 to 48, it can be seen that, using the device of FIG. 1 , when the content of the water-soluble polymer having a number average molecular weight Mn of 560 or more and 3,300 or less is 11.0 mass % or more and 30.0 mass % or less with respect to the ink, and the content of the compound having a structure represented by structural formula (1) is 0.2 mass % or more and 1.5 mass % or less with respect to the cleaning liquid, both image density and maintainability are achieved.
A comparison of Examples 1 to 16 shows that the image density is better when the number average molecular weight Mn of the water-soluble polymer is 900 or more. It is also shown that the maintainability is better when the number average molecular weight Mn of the water-soluble polymer is 2,200 or less.
Comparisons of Examples 6 and 7 with Examples 5 and 8, and comparisons of Examples 10 and 11 with Examples 9 and 12 show that image density and maintainability are better balanced when the content of the water-soluble polymer is 15.0% by mass or more and 20.0% by mass or less.
By comparing Examples 6 and 17 to 23 with Examples 24 to 32 and 42 to 44 with Examples 22 to 30 and 40 to 44, it is found that the maintainability is better when the content of the compound that does not have the structure represented by structural formula (2) and Si and has 8 or more carbon atoms is 1.0 mass% or more and 10.0 mass% or less with respect to the cleaning liquid.
By comparing Examples 6, and 17 to 23 with Examples 33 to 44, it can be seen that the maintainability is better when the content of the compound having the structure represented by structural formula (2) and having no Si is 1.0 mass% or more and 6.0 mass% or less with respect to the cleaning liquid.
By comparing Examples 6, 46, and 47 with Examples 45 and 48, it can be seen that the maintainability is better when the content of the compound having a structure represented by structural formula (1) is 0.8 mass% or more and 1.2 mass% or less with respect to the cleaning liquid.
A comparison of Examples 1 to 48 with Comparative Examples 1 to 8 reveals that when the content of the water-soluble polymer is less than 11.0% by mass, the image density falls outside the allowable range, and when the content of the water-soluble polymer is more than 30.0% by mass, the maintainability falls outside the allowable range.
A comparison of Examples 1 to 48 and Comparative Examples 9 to 13 reveals that when the content of the compound having a structure represented by Structural Formula (1) is not 0.2% by mass or more and 1.5% by mass or less with respect to the cleaning liquid, the maintainability falls outside the allowable range.
A comparison of Examples 1 to 48 with Comparative Example 14 shows that the maintenance performance is outside the acceptable range in a configuration in which ink is pressurized to form droplets of the ink on the nozzle surface and then cleaning liquid is sprayed.
A comparison of Examples 1 to 48 with Comparative Example 15 reveals that the maintenance performance is outside the acceptable range in a configuration in which ink is pressurized to form ink droplets on the nozzle surface and then wiped away by a blade member.

For example, aspects 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 ejection head having a nozzle surface provided with nozzles for ejecting the ink;
A cleaning solution containing a compound having a structure represented by the following structural formula (1):
an ejection member that ejects the cleaning liquid onto the nozzle surface;
a pressure member that pressurizes the ink to form droplets of the ink on the nozzle surface;
a blade member that comes into contact with the nozzle surface and wipes the nozzle surface onto 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 with respect 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 with respect to the cleaning liquid.
<2> The cleaning solution contains a compound having a structure represented by the following structural formula (2), no Si, and 8 or more carbon atoms,
The ink jet recording apparatus according to <1>, wherein the content of the compound is 1.0% by mass or more and 10.0% by mass or less with respect to the cleaning liquid.
<3> The cleaning solution contains a compound having a structure represented by the following structural formula (2) and having no Si,
The inkjet recording apparatus according to any one of <1> to <2>, wherein the content of the compound having the structure represented by the structural formula (2) and having no Si is 1.0 mass % to 6.0 mass % or less with respect to the cleaning liquid.
<4> The inkjet recording apparatus according to any one of <1> to <2>, wherein a content of the compound having a structure represented by the structural formula (1) is 0.8% by mass or more and 1.2% by mass or less with respect to the cleaning liquid.
<5> The inkjet recording apparatus according to any one of <1> and <2>, wherein the water-soluble polymer has a number average molecular weight Mn of 900 or more and 2,200 or less.
<6> The recording apparatus according to any one of <1> and <2>, wherein the content of the water-soluble polymer in the ink is 15.0% by mass to 20.0% by mass.
<7> an ink ejection step of ejecting an ink containing a water-soluble polymer having a number average molecular weight Mn of 560 or more and 3,300 or less from a nozzle surface of a liquid ejection head;
a spraying step of spraying a cleaning liquid containing a compound having a structure represented by the following structural formula (1) onto the nozzle surface;
a pressurizing step of pressurizing the ink to form droplets of the ink on the nozzle surface;
a wiping step of wiping the nozzle surface onto which the cleaning liquid has been sprayed by contacting the nozzle surface 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 with respect to the ink,
The inkjet recording method is characterized in that 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 with respect to the cleaning liquid.

The inkjet recording device described in any one of <1> to <6> and the inkjet recording device described in <7> can solve the above-mentioned problems in the past and achieve the object of the present invention.

Reference Signs List 1 Liquid ejection head 2 Blade member 3 Spray mechanism 4 Wiping mechanism 5 Liquid ejection head 6 Blade member 7 Spray mechanism 8 Wiping mechanism 9 Liquid ejection head 10 Blade member 11 Wiping mechanism 12 Paper feed device 13 Winding device 14 Liquid ejection head 15 IR heater 16 Hot air device 17 Exhaust duct P Continuous paper

JP 2015-052084 A JP 2021-075015 A

Claims (7)

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 ejection head having a nozzle surface provided with nozzles for ejecting the ink;
A cleaning solution containing a compound having a structure represented by the following structural formula (1):
an ejection member that ejects the cleaning liquid onto the nozzle surface;
a pressure member that pressurizes the ink to form droplets of the ink on the nozzle surface;
a blade member that comes into contact with the nozzle surface and wipes the nozzle surface onto 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 with respect to the ink,
An ink-jet recording apparatus, characterized in that the content of the compound having a structure represented by the structural formula (1) is 0.2% by mass or more and 1.5% by mass or less with respect to the cleaning liquid. The cleaning solution contains a compound having a structure represented by the following structural formula (2), no Si, and no carbon number of 8:
2. The inkjet recording apparatus according to claim 1, wherein the content of the compound is 1.0% by mass or more and 10.0% by mass or less with respect to the cleaning liquid.
The cleaning solution contains a compound having a structure represented by the following structural formula (2) and not having Si,
3. The inkjet recording apparatus according to claim 1, wherein the content of the compound having the structure represented by structural formula (2) and not having Si is 1.0% by mass to 6.0% by mass or less with respect to the cleaning liquid.
The inkjet recording device 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 with respect to the cleaning liquid. The inkjet recording device 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. A recording device according to any one of claims 1 to 2, wherein the content of the water-soluble polymer in the ink is 15.0% by mass or more and 20.0% by mass or less. an ink ejection step of ejecting ink containing a water-soluble polymer having a number average molecular weight Mn of 560 or more and 3,300 or less from a nozzle surface of a liquid ejection head;
a spraying step of spraying a cleaning liquid containing a compound having a structure represented by the following structural formula (1) onto the nozzle surface;
a pressurizing step of pressurizing the ink to form droplets of the ink on the nozzle surface;
a wiping step of wiping the nozzle surface onto which the cleaning liquid has been sprayed by contacting the nozzle surface 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 with respect to the ink,
The ink-jet recording method according to claim 1, wherein the content of the compound having the structure of the structural formula (1) is from 0.2% by mass to 1.5% by mass with respect to the cleaning liquid.

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