White inkjet ink composition and inkjet recording method

Abstract

To provide a white ink jet ink composition that suppresses the precipitation of a white pigment and can form an image having excellent color development and excellent fabric followability.SOLUTION: A white ink jet ink composition includes hollow resin particles, resin particles, and water. The glass transition temperature of the hollow resin particles is 120°C or higher, and the glass transition temperature of the resin particles is 5°C or lower.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a white inkjet ink composition and an inkjet recording method. [Background technology]

[0002] The inkjet method has been the subject of various technological developments since it can form high-quality images on recording media. Not only has inkjet recording apparatus been developed, but a very wide range of developments have been made, including studies on ink compositions to be used therein, and studies on ink compositions and recording methods suited to the target recording media.

[0003] For example, Patent Document 1 discloses a water-based white pigment ink for inkjet recording to be used on fabric, in which the white pigment in the ink is made less likely to penetrate into the interior of the fabric, thereby improving the whiteness on the fabric, and a binder is used to improve the washing fastness of the white pigment that remains on the surface of the fabric. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-179263 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when recording a white image on a fabric by an inkjet method, it is necessary to suppress sedimentation of the white pigment in the ink used and to enhance the color development of the image, but it is also necessary for the image to conform to the fabric. That is, depending on the type of fabric, a white inkjet ink composition is required that suppresses image cracking due to the expansion and contraction of the fabric. [Means for solving the problem]

[0006] One embodiment of the white inkjet ink composition according to the present invention comprises: Contains hollow resin particles, resin particles, and water, The glass transition temperature of the hollow resin particles is 120°C or higher, The resin particles have a glass transition temperature of 5° C. or lower.

[0007] The inkjet recording method according to the present invention comprises: The method includes a white ink deposition step in which the above-mentioned white inkjet ink composition is ejected from a recording head and deposited on a recording medium. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a schematic configuration of a first embodiment of a recording apparatus in a see-through state. [Figure 2] FIG. 2 is a perspective view showing an ink supply unit provided in the housing of the recording apparatus. [Figure 3] FIG. [Figure 4] FIG. 4 is a partially broken cross-sectional view taken along line 4-4 in FIG. 3. [Figure 5] FIG. 5 is a partially broken cross-sectional view taken along line 5-5 in FIG. 3. [Figure 6] FIG. 4 is a perspective view of the ink container with the cap removed. [Figure 7] FIG. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] 10 is a cross-sectional view taken along line 10-10 in FIG. 9. [Figure 11] 11 is a cross-sectional view taken along line 11-11 in FIG. 9. [Figure 12] FIG. 10 is a partially cutaway front view showing a state immediately before ink is replenished to the ink accommodating body. [Figure 13] FIG. 10 is a partially cutaway side view showing a state immediately before ink is replenished to the ink accommodating body. [Figure 14] FIG. 10 is a partially cutaway front view showing a state in which ink is being refilled into the ink container. [Figure 15] FIG. 10 is a partially cutaway side view showing a state in which ink is being refilled into the ink container. [Figure 16] FIG. 10 is a partially cutaway front view showing a state in which the positioning portion of the ink accommodating body abuts against a receiving surface on the ink accommodating body side during ink replenishment. [Figure 17] FIG. 10 is a partially cutaway side view showing a state in which the positioning portion of the ink accommodating body abuts against a receiving surface on the ink accommodating body side during ink refilling. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes embodiments of the present invention. The embodiments described below are examples of the present invention. The present invention is not limited to the following embodiments, and includes various modified forms that are implemented within the scope of the present invention. Note that not all of the configurations described below are necessarily essential configurations of the present invention.

[0010] In this specification, "(meth)acrylic" refers to acrylic or methacrylic, and "(meth)acrylate" refers to acrylate or methacrylate.

[0011] 1. White inkjet ink composition The white inkjet ink composition according to this embodiment contains hollow resin particles, resin particles, and water.

[0012] 1.1.Hollow resin particles The hollow resin particles contained in the white inkjet ink composition of this embodiment have a glass transition temperature (Tg) of 120°C or higher. That is, the Tg of the polymer that constitutes the hollow resin particles is 120°C or higher. By using such hollow resin particles, the structure of the hollow resin particles is less likely to change when the white inkjet ink composition attached to a recording medium is dried by heating. Therefore, the light scattering by the hollow resin particles is less likely to change, and good color development can be maintained.

[0013] The hollow resin particles are not particularly limited, and known ones can be used as long as they have a Tg of 120° C. or higher. For example, hollow resin particles having a Tg of 120° C. or higher such as those described in U.S. Pat. No. 4,880,465 and Japanese Patent No. 3,562,754 can be used.

[0014] Hollow resin particles are resin particles that have voids inside the resin particles and that are filled with a liquid or gas. Hollow resin particles can be determined by observing the cross section of a particle with a scanning electron microscope, if the particle has a structure in which voids are visible inside the particle. Alternatively, hollow resin particles can be determined by observing the particle with a transmission electron microscope, if the particle has a structure in which a difference in the contrast of transmitted electrons is visible. In transmission electron microscope observation, if a resin particle has voids inside, the internal voids are easily transmitted by electron beams and are observed with bright contrast, so the presence or absence of internal voids can be determined by the presence or absence of a difference in the contrast of transmitted electrons.

[0015] The hollow resin particles may be prepared and used, or commercially available products may be used. For example, the hollow resin particles may be prepared by a so-called emulsion polymerization method in which a monomer, a surfactant, a polymerization initiator, and an aqueous dispersion medium are heated and stirred under a nitrogen atmosphere to form a hollow resin particle emulsion.

[0016] Examples of the monomer include nonionic monoethylenically unsaturated monomers, such as styrene, vinyltoluene, ethylene, vinyl acetate, vinyl chloride, vinylidene chloride, and acrylonitrile. Furthermore, (meth)acrylic acid and its derivatives may also be used as the monomer, such as (meth)acrylic acid, (meth)acrylamide, and (meth)acrylic acid esters. Examples of the (meth)acrylic acid esters include methyl acrylate, methyl methacrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-hydroxyethyl methacrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, lauryl (meth)acrylate, oleyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate.

[0017] Furthermore, a bifunctional monomer can also be used as the monomer. Examples of bifunctional vinyl monomers include divinylbenzene, and examples of bifunctional (meth)acrylic monomers include allyl methacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, diethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate. By copolymerizing a monofunctional monomer and a bifunctional monomer to achieve a high degree of crosslinking, hollow resin particles can be obtained that not only have light scattering properties but also have heat resistance, solvent resistance, and solvent dispersibility.

[0018] The surfactant may be any surfactant that forms molecular aggregates such as micelles in water, and examples thereof include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants.

[0019] As the polymerization initiator, a known compound soluble in water can be used, and examples thereof include hydrogen peroxide and potassium persulfate.

[0020] Examples of aqueous dispersion media include water and water containing a hydrophilic organic solvent.

[0021] On the other hand, commercially available hollow resin particles may be used. Examples of commercially available products include ROPAQUE HT1432 (trade name, manufactured by The Dow Chemical Company, styrene-acrylic resin, Tg: 123°C, particle size: 500 nm). These may be used alone or in combination of two or more.

[0022] In this specification, a polymer containing a (meth)acrylic acid derivative as a repeating unit is referred to as an “acrylic resin.” For example, the above-mentioned “styrene-acrylic resin,” “crosslinked styrene-acrylic resin,” and “modified styrene-acrylic resin” are examples of “acrylic resin.”

[0023] The resin composition of the hollow resin particles can be an acrylic resin, a urethane resin, a maleic resin, or the like, and these may be used alone or in combination of two or more.

[0024] Furthermore, although it depends on the resin composition of the hollow resin particles, the glass transition temperature (Tg) of the hollow resin particles is preferably 125°C or higher, more preferably 130°C or higher, and even more preferably 135°C or higher. The Tg of the hollow resin particles is preferably equal to or higher than the surface temperature of the recording medium heated in the heat drying step of the inkjet recording method. Considering the whiteness of the image formed with the white inkjet ink composition, there is no particular upper limit to the Tg. However, if the Tg is too high, the image may not conform to the fabric. The upper limit of the glass transition temperature of the hollow resin particles is not particularly limited, but is preferably 180°C or lower, more preferably 170°C or lower, and even more preferably 160°C or lower.

[0025] Furthermore, the material of the hollow resin particles preferably contains an acrylic resin, which makes it easier to obtain hollow resin particles having a glass transition temperature of 120°C or higher, and also makes it easier to adjust the glass transition temperature.

[0026] When hollow resin particles are obtained by polymerization, the glass transition temperature of the hollow resin particles can be changed by changing at least one of the types and composition ratios of the monomers used, the polymerization conditions, and the modification of the resin. Polymerization conditions include the temperature during polymerization, the type of medium containing the monomers, the monomer concentration in the medium, and the types and amounts of polymerization initiators and catalysts used during polymerization. The glass transition temperature can be measured by differential scanning calorimetry (DSC) in accordance with JIS K7121.

[0027] The content (solid content) of the hollow resin particles is preferably 1% by mass to 20% by mass, and more preferably 5% by mass to 15% by mass, based on the total amount of the white inkjet ink composition. By keeping the content (solid content) within this range, in particular by not exceeding 20% ​​by mass, reliability such as preventing clogging of the inkjet recording head is improved, while by keeping the content (solid content) below 1% by mass, sufficient color density such as whiteness is ensured.

[0028] Furthermore, the hollow resin particles preferably have a resin shell and contain a gas such as air. "Hollow" refers to a structure in which the inside of an object is empty, specifically, a structure having at least one of a space capable of containing a gas such as air and holes through which a gas such as air can constantly pass. The hollow resin particles exhibit a white color and excellent opacity due to light scattering caused by the difference in refractive index between the air layer inside the particle and the polymer layer of the shell after drying.

[0029] It is desirable that the hollow resin particles do not precipitate or float up in the white inkjet ink composition. Therefore, the specific gravity may be adjusted appropriately. For example, the dispersion stability in the ink can be adjusted by adjusting the shell thickness of the hollow resin particles or the specific gravity of the polymer that constitutes the shell. Furthermore, the hollow resin particles may have a structure in the white inkjet ink composition that is filled with a vehicle component primarily composed of water or an organic solvent. In this case, the specific gravity of the hollow resin particles can be made close to the specific gravity of the vehicle component. This can prevent the hollow resin particles from settling or floating up in the white inkjet ink composition.

[0030] Furthermore, when the white inkjet ink composition dries, the hollow resin particles exhibit a better white color due to the evaporation of the vehicle components, which causes more pronounced light scattering at the interface between the shell polymer and the inner cavity.

[0031] The hollow resin particles preferably have an average particle diameter (outer diameter) of 200 nm to 1.5 μm, more preferably 300 nm to 1.0 μm, and even more preferably 400 nm to 800 nm. The hollow resin particles preferably have an inner diameter of approximately 50 nm to 1.2 μm.

[0032] The average particle size of the hollow resin particles can be measured using a particle size distribution analyzer that uses a laser diffraction scattering method as its measurement principle. For example, a particle size distribution analyzer that uses a dynamic light scattering method as its measurement principle (e.g., "Microtrac UPA" manufactured by Nikkiso Co., Ltd.) can be used as the laser diffraction particle size distribution analyzer to determine the volume-based average particle size.

[0033] The white inkjet ink composition may contain other coloring materials in addition to the hollow resin particles, such as general-purpose pigments and dyes.

[0034] 1.2.Resin particles The white inkjet ink composition contains resin particles. The resin particles contained in the white inkjet ink composition have a glass transition temperature (Tg) of 5.0°C or less. That is, the Tg of the polymer constituting the resin particles is 5.0°C or less. By using such resin particles, the white inkjet ink composition adhered to a recording medium can be more easily fixed. Furthermore, by using resin particles having a Tg of 5.0°C or less, hollow resin particles having a Tg of 120°C or more can also be well fixed. Furthermore, by using resin particles having a Tg of 5.0°C or less, even if the recording medium expands or contracts, the resin particles can easily expand or contract in accordance with the expansion or contraction, thereby suppressing image cracking and the like. Note that, unlike hollow resin particles, the resin particles are solid rather than hollow.

[0035] Examples of resin particles include those made of urethane resins, acrylic resins (including styrene-acrylic resins), fluorene resins, olefin resins, rosin-modified resins, terpene resins, ester resins, amide resins, epoxy resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymers, ethylene vinyl acetate resins, etc., with a Tg of 5°C or less. Among these, urethane resins, acrylic resins, olefin resins, and ester resins are preferred. The resin particles may be used alone or in combination of two or more types.

[0036] Urethane resin is a general term for resins having urethane bonds. In addition to urethane bonds, the urethane resin may also include polyether-type urethane resins containing ether bonds in the main chain, ester-type urethane resins containing ester bonds in the main chain, and carbonate-type urethane resins containing carbonate bonds in the main chain. Furthermore, commercially available urethane resins may be used. For example, commercially available products such as Superflex 460, 460s, 840, and E-4000 (trade names, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Rezamin D-1060, D-2020, D-4080, D-4200, D-6300, and D-6455 (trade names, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), Takelac WS-5100, WS-6021, and W-512-A-6 (trade names, manufactured by Mitsui Chemicals Polyurethanes Inc.), Sancure 2710 (trade name, manufactured by Lubrizol), and Permarin UA-150 (trade name, manufactured by Sanyo Chemical Industries, Ltd.) may be selected and used.

[0037] Acrylic resin is a general term for polymers obtained by polymerizing at least an acrylic monomer such as (meth)acrylic acid or a (meth)acrylic acid ester as one component. Examples include resins obtained from acrylic monomers and copolymers of acrylic monomers with other monomers. Examples include acrylic-vinyl resins, which are copolymers of acrylic monomers and vinyl monomers. Another example of a vinyl monomer is styrene.

[0038] Examples of acrylic monomers that can be used include acrylamide and acrylonitrile. Commercially available products may be used for the resin emulsion made from an acrylic resin, such as FK-854 (trade name, manufactured by Chuo Rika Kogyo Co., Ltd.), Movinyl 952B and 718A (trade names, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and Nipol LX852 and LX874 (trade names, manufactured by Nippon Zeon Co., Ltd.).

[0039] The term "acrylic resin" is the same as that used for the hollow resin particles.

[0040] Styrene-acrylic resins are copolymers obtained from styrene monomers and (meth)acrylic monomers, and include styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-α-methylstyrene-acrylic acid copolymers, and styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymers. The styrene-acrylic resin may be a commercially available product, such as JONCRYL 62J, 7100, 390, 711, 511, 7001, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, or 7610 (trade names, manufactured by BASF), Mowinyl 966A or 975N (trade names, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), or Vinyblan 2586 (manufactured by Nissin Chemical Industry Co., Ltd.).

[0041] The olefin resin is a polymer having an olefin such as ethylene, propylene, or butylene in its structural skeleton, and any known resin can be appropriately selected and used. As the olefin resin, commercially available products can be used, such as Arrowbase CB-1200 and CD-1200 (trade names, manufactured by Unitika Ltd.).

[0042] The resin particles may also be supplied in the form of an emulsion. Examples of commercially available resin emulsions include Microgel E-1002 and E-5002 (trade names of Nippon Paint Co., Ltd., styrene-acrylic resin emulsions), Boncoat 4001 (trade name of DIC Corporation, acrylic resin emulsion), Boncoat 5454 (trade name of DIC Corporation, styrene-acrylic resin emulsion), Polysol AM-710, AM-920, AM-2300, AP-4735, AT-860, PSASE-4210E ( ... Polysol AP-7020 (styrene-acrylic resin emulsion), Polysol SH-502 (vinyl acetate resin emulsion), Polysol AD-13, AD-2, AD-10, AD-96, AD-17, AD-70 (ethylene-vinyl acetate resin emulsion), Polysol PSASE-6010 (ethylene-vinyl acetate resin emulsion) (product name, manufactured by Showa Denko K.K.), Polysol SAE1014 (product name, styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Saivinol SK-200 (product name, acrylic resin emulsion, manufactured by Saiden Chemical Co., Ltd.) , AE-120A (trade name, acrylic resin emulsion, manufactured by JSR Corporation), AE373D (trade name, carboxy-modified styrene-acrylic resin emulsion, manufactured by E-Tech Co., Ltd.), Seikadyne 1900W (trade name, ethylene-vinyl acetate resin emulsion, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), Vinyblan 2682 (acrylic resin emulsion), Vinyblan 2886 (vinyl acetate-acrylic resin emulsion), Vinyblan 5202 (acetic acid acrylic resin emulsion) (trade name, manufactured by Nissin Chemical Industry Co., Ltd.), Elitel KA-5071S, KT-8803, KT-9204, KT-870 1, KT-8904, KT-0507 (trade names of Unitika Ltd., polyester resin emulsion), Hi-Tec SN-2002 (trade name of Toho Chemical Co., Ltd., polyester resin emulsion), Takelac W-6020, W-635, W-6061, W-605, W-635, W-6021 (trade names of Mitsui Chemicals Polyurethanes, urethane resin emulsion), Superflex 870, 800, 150, 420, 460, 470, 610, 700 (trade names of Daiichi Kogyo Seiyaku Co., Ltd., urethane resin emulsion), Parmarin UA-150 (trade name of Sanyo Chemical Industries, Ltd.,Urethane resin emulsion), Sancure 2710 (manufactured by Lubrizol Japan, urethane resin emulsion), NeoRez R-9660, R-9637, R-940 (manufactured by Kusumoto Chemicals Co., Ltd., urethane resin emulsion), Adeka Bontitor HUX-380, 290K (manufactured by ADEKA Corporation, urethane resin emulsion), Mowinyl 966A, Mowinyl 7320 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Joncryl 7100, 390, 711, 511, 7001, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, P Examples of binders include DX-7630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, and 7610 (all manufactured by BASF), NK Binder R-5HN (manufactured by Shin-Nakamura Chemical Co., Ltd.), Hydran WLS-210 (non-crosslinked polyurethane: manufactured by DIC Corporation), and Joncryl 7610 (manufactured by BASF).

[0043] The resin particles are more preferably selected from urethane-based resins and acrylic-based resins, which tends to further improve the fabric conformability of images formed with the white inkjet ink composition.

[0044] The lower limit of the glass transition temperature of the resin particles is not particularly limited, but is preferably −35° C. or higher, more preferably −30° C. or higher, in order to improve the storage stability of the white inkjet ink composition and further suppress clogging of the nozzles. The upper limit of the glass transition temperature of the resin particles is not particularly limited, but is preferably 0° C. or lower, more preferably −15° C. or lower, and even more preferably −20° C. or lower.

[0045] The content of resin particles in the white inkjet ink composition is, in terms of solids content, 0.1% by mass to 15% by mass, preferably 1% by mass to 15% by mass, more preferably 2% by mass to 10% by mass, and even more preferably 3% by mass to 7% by mass, relative to the total mass of the white inkjet ink composition.

[0046] 1.3.Water The white inkjet ink composition according to this embodiment contains water. Examples of water include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, as well as ultrapure water, which has reduced ionic impurities. Furthermore, using water that has been sterilized by ultraviolet irradiation or the addition of hydrogen peroxide can suppress the growth of bacteria and fungi when the white inkjet ink composition is stored for a long period of time.

[0047] The water content of the white inkjet ink composition is 30% by mass or more, preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more, based on the total amount of the white inkjet ink composition. Note that the water in the white inkjet ink composition includes, for example, water contained in raw materials, as well as added water. A water content of 30% by mass or more allows the white inkjet ink composition to have a relatively low viscosity. Furthermore, the upper limit of the water content of the white inkjet ink composition is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, based on the total amount of the white inkjet ink composition.

[0048] 1.4.Other Ingredients The white inkjet ink composition may contain the following components in addition to hollow resin particles, resin particles, and water.

[0049] 1.4.1. Organic Solvents The white inkjet ink composition according to this embodiment may contain an organic solvent. The organic solvent is preferably a water-soluble organic solvent. One function of the organic solvent is to improve the wettability of the ink with respect to the recording medium and to increase the moisture retention of the ink. Examples of the water-soluble organic solvent include polyhydric alcohols, alkylene glycol ethers, esters, cyclic esters, and nitrogen-containing solvents.

[0050] <Polyhydric alcohol> Examples of polyhydric alcohols include polyhydric alcohols having a standard boiling point of 270°C or higher, and polyhydric alcohols having a standard boiling point of 150°C or higher but lower than 270°C.

[0051] (Normal boiling point is 270°C or higher) Examples of polyhydric alcohols having a standard boiling point of 270°C or higher include triethylene glycol (standard boiling point: 287°C), glycerin (standard boiling point: 290°C), trimethylolpropane (standard boiling point: 295°C), and polyethylene glycol monomethyl ether.

[0052] (Normal boiling point is between 150℃ and 270℃) Examples of polyhydric alcohols having a normal boiling point of 150° C. or higher and lower than 270° C. include 1,2-alkanediols and polyols.

[0053] Examples of 1,2-alkanediols include ethylene glycol, propylene glycol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, and 1,2-octanediol.

[0054] Examples of polyols include diethylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,3-butanediol, 2-ethyl-1,3-hexanediol, 3-methyl-1,5-pentanediol, and 2-methylpentane-2,4-diol.

[0055] <Alkylene glycol ethers> The alkylene glycol ethers may be monoethers or diethers of alkylene glycol, and alkyl ethers are preferred.

[0056] Examples of alkylene glycol monoalkyl ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, etc. Alkylene glycol monoalkyl ethers are sometimes classified as monohydric alcohols.

[0057] Examples of alkylene glycol dialkyl ethers include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl butyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol methyl butyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and tripropylene glycol dimethyl ether.

[0058] <Esters> Examples of esters include glycol monoacetates and glycol diesters. It can be obtained.

[0059] Examples of glycol monoacetates include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and methoxybutyl acetate.

[0060] Examples of glycol diesters include ethylene glycol diacetate, diethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, diethylene glycol acetate butyrate, diethylene glycol acetate propionate, diethylene glycol acetate butyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate, dipropylene glycol acetate butyrate, and dipropylene glycol acetate propionate.

[0061] <Cyclic esters> Examples of cyclic esters include cyclic esters (lactones) such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, β-butyrolactone, β-valerolactone, γ-valerolactone, β-hexanolactone, γ-hexanolactone, δ-hexanolactone, β-heptanolactone, γ-heptanolactone, δ-heptanolactone, ε-heptanolactone, γ-octanolactone, δ-octanolactone, ε-octanolactone, δ-nonalactone, ε-nonalactone, and ε-decanolactone, as well as compounds in which the hydrogen atom of the methylene group adjacent to the carbonyl group of these cyclic esters is substituted with an alkyl group having 1 to 4 carbon atoms.

[0062] <Nitrogen-containing solvent> Examples of the nitrogen-containing solvent include cyclic amides and non-cyclic amides. Examples of the non-cyclic amides include alkoxyalkyl amides.

[0063] (cyclic amides) Examples of cyclic amides include lactams, such as pyrrolidones such as 2-pyrrolidone, 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-propyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone, which are preferred in terms of accelerating the formation of a film on the resin particles, with 2-pyrrolidone being particularly preferred.

[0064] (Acyclic amides) Examples of alkoxyalkylamides include 3-methoxy-N,N-dimethylpropionamide, 3-methoxy-N,N-diethylpropionamide, 3-methoxy-N,N-methylethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, 3-ethoxy-N,N-diethylpropionamide, 3-ethoxy-N,N-methylethylpropionamide, 3-n-butoxy-N,N-dimethylpropionamide, and 3-n-butoxy-N,N-diethylpropionamide. amide, 3-n-butoxy-N,N-methylethylpropionamide, 3-n-propoxy-N,N-dimethylpropionamide, 3-n-propoxy-N,N-diethylpropionamide, 3-n-propoxy-N,N-methylethylpropionamide, 3-iso-propoxy-N,N-dimethylpropionamide, 3-iso-propoxy-N,N-diethylpropionamide, 3-iso-propoxy-N,N-methylethylpropionamide, 3-tert-butoxy-N,N-di Examples include methylpropionamide, 3-tert-butoxy-N,N-diethylpropionamide, and 3-tert-butoxy-N,N-methylethylpropionamide.

[0065] It is also preferable to use alkoxyalkylamides, which are compounds represented by the following general formula (1), as the non-cyclic amides.

[0066] R 1 -O-CH2CH2-(C=O)-NR 2 R 3 ···(1)

[0067] In the above formula (1), R 1 represents an alkyl group having 1 to 4 carbon atoms, and R 2 and R 3each independently represents a methyl group or an ethyl group. The "alkyl group having 1 to 4 carbon atoms" can be a linear or branched alkyl group, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, or a tert-butyl group. The compound represented by the above formula (1) may be used alone or in combination of two or more types.

[0068] These organic solvents may be used alone or in combination of two or more.

[0069] The white inkjet ink composition of this embodiment preferably contains an alkanediol having a normal boiling point of 240°C or less and having 4 to 6 carbon atoms, in which at least one hydroxyl group is bonded to a position other than the end of the alkane chain, and more preferably in an amount of 75.0 mass% or more relative to the total amount of the water-soluble organic solvent.

[0070] In this way, even if the white image formed on the recording medium is quickly heated and dried, it is possible to suppress a decrease in the whiteness of the white image.

[0071] The number of carbon atoms in the alkanediol having a normal boiling point of 240°C or less and at least one hydroxyl group bonded to a site other than the end of the alkane chain is 4 or more and 6 or less, and preferably 4 or more and 5 or less. Having a carbon number of 4 or more and 6 or less is preferred in terms of suppressing softening of the hollow resin particles and improving the drying properties of the white inkjet ink composition after image formation.

[0072] The alkanediol having 4 to 6 carbon atoms and a normal boiling point of 240°C or less, in which at least one hydroxyl group is bonded to a site other than the end of the alkane chain, is one in which at least one of the alcoholic hydroxyl groups is bonded to a site other than the end of the alkane chain. By having at least one hydroxyl group bonded to a site other than the end of the alkane chain, the whiteness of the white image can be improved.

[0073] Examples of alkanediols having 4 to 6 carbon atoms and a standard boiling point of 240°C or less, in which at least one hydroxyl group is bonded to a position other than the end of the alkane chain, include 1,2-butanediol (standard boiling point: 194°C), 1,3-butanediol (standard boiling point: 203°C), 2,3-butanediol (standard boiling point: 183°C), 1,2-propanediol (standard boiling point: 188°C), 3-methyl-1,3-butanediol (standard boiling point: 203°C), and 2-methyl-2,4-pentanediol (standard boiling point: 197°C). These may be used alone or in combination of two or more.

[0074] Among these, from the viewpoint of the whiteness of a white image, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, and 2-methyl-2,4-pentanediol are preferred, and 3-methyl-1,3-butanediol and 2-methyl-2,4-pentanediol are more preferred.

[0075] The content of the alkanediol having 4 to 6 carbon atoms and having a normal boiling point of 240°C or less and at least one hydroxyl group bonded to a position other than the end of the alkane chain is more preferably 80.0 mass% or more, and even more preferably 88.0 mass% or more, based on the total amount of the water-soluble organic solvent.

[0076] 1.4.2. pH adjusters The white inkjet ink composition according to this embodiment may contain a pH adjuster. Examples of pH adjusters include, but are not limited to, acids, bases, weak acids, weak bases, and appropriate combinations thereof, such as tertiary alkanolamines such as triethanolamine and triisopropanolamine. When a pH adjuster is added, its total amount is preferably from 0.01% to 2.0% by mass, more preferably from 0.1% to 1.0% by mass, and even more preferably from 0.2% to 0.5% by mass, relative to the total mass of the ink composition.

[0077] Surfactants The white inkjet ink composition according to this embodiment may contain a surfactant. The surfactant can be used as a wetting agent to reduce the surface tension of the ink composition and adjust the wettability and permeability of the ink composition to a recording medium. Furthermore, by including a surfactant in the ink composition, the reliability of ejection from an inkjet head is ensured.

[0078] The surfactant may be any of nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants, and these may be used in combination. Among the surfactants, acetylene glycol surfactants, silicone surfactants, and fluorine surfactants are preferably used.

[0079] The acetylene glycol surfactant is not particularly limited, but examples thereof include Surfynol (registered trademark) 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, and DF110D (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), Olfine (registered trademark) B, Y , P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, PD-005, EXP.4001, EXP.4300, EXP.4036, EXP.4051, AF-103, AF-104, AK-02, SK-14, AE-3 (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), Acetylenol (registered trademark) E00, E00P, E40, E100 (all trade names, manufactured by Kawaken Fine Chemicals Co., Ltd.).

[0080] The silicone surfactant is not particularly limited, but a polysiloxane compound is preferred. The polysiloxane compound is not particularly limited, but examples thereof include polyether-modified organosiloxane. Commercially available polyether-modified organosiloxanes include, for example, BYK (registered trademark)-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, and BYK-348 (all trade names, manufactured by BYK), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0081] As the fluorine-based surfactant, it is preferable to use a fluorine-modified polymer, and there are no particular limitations. Although not particularly limited, for example, BYK (registered trademark)-340 (trade name, manufactured by BYK Japan Co., Ltd.) can be mentioned.

[0082] When the ink composition contains a surfactant, multiple types of the surfactants can be used, and the total content of the surfactants is preferably 0.01% by mass or more and 3.0% by mass or less, more preferably 0.05% by mass or more and 2.0% by mass or less, even more preferably 0.1% by mass or more and 1.5% by mass or less, and particularly preferably 0.2% by mass or more and 1.0% by mass or less, relative to the total mass of the ink.

[0083] 1.4.4. Ingredients other than those listed above The white inkjet ink composition according to this embodiment may contain, in addition to the components described above, additives that can be typically used in inkjet inks, such as a chelating agent, a preservative, a mildewproofing agent, a rust inhibitor such as benzotriazole, an antioxidant, an ultraviolet absorber, an oxygen absorber, and a solubilizing agent.

[0084] 1.5. Relationships between ingredients (Materials of resin particles and hollow resin particles) In the white inkjet ink composition of this embodiment, it is more preferable that at least one of the resin particles and the hollow resin particles contains an anionic resin. Examples of the anionic resin include resins having an anionic group such as a carboxyl group, a sulfonic acid group, or a phosphate group, and can be selected from acrylic acid-based resins, urethane-based resins, etc.

[0085] When at least one of the resin particles and the hollow resin particles contains such an anionic resin, when the white inkjet ink composition comes into contact with a cationic compound, at least one of the resin particles and the hollow resin particles is more likely to aggregate, thereby making it possible to obtain images with even better image quality.

[0086] (Relationship with glass transition temperature) The absolute value of the difference between the glass transition temperatures of the hollow resin particles and the resin particles is more preferably 125° C. or higher, even more preferably 130° C. or higher, and particularly preferably 135° C. or higher. Selecting the resin particles and hollow resin particles so as to achieve such a difference in glass transition temperatures can further improve the color development of the image and the conformability to the fabric.

[0087] 1.6. Preparation method and physical properties (preparation) The white inkjet ink composition according to this embodiment can be obtained by mixing the above-described components in any order and, if necessary, removing impurities by filtration or the like. A suitable method for mixing the components is to sequentially add the materials to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer and stir and mix them. Filtration can be performed, if necessary, by centrifugal filtration, filter filtration, or the like.

[0088] (surface tension) In this embodiment, from the viewpoint of balancing print quality and reliability as an inkjet ink, the ink composition preferably has a surface tension at 20°C of 20 mN / m or more and 40 mN / m or less, and more preferably 30 mN / m or more and 36 mN / m or less. Having a surface tension within this range not only provides excellent ejection reliability in inkjet recording, but also makes it easier for the ink to wet, spread evenly, and penetrate onto the recording medium when applied to the recording medium. This may also make it easier for the ink to be fixed to the recording medium.

[0089] The surface tension can be measured, for example, using an automatic surface tensiometer CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.) by checking the surface tension when a platinum plate is wetted with ink in an environment of 20° C. One method for keeping the surface tension within the above ranges includes appropriately adjusting the types of the organic solvent and surfactant described above, and the amounts of these and water added.

[0090] (viscosity) Furthermore, the viscosity of the ink at 20°C is preferably from 1.5 to 15.0 mPa·s, more preferably from 1.5 to 5.0 mPa·s, and even more preferably from 1.5 to 3.6 mPa·s. When the viscosity of the ink at 20°C is within the above range, the ink is more easily fixed when applied to a recording medium, which may improve color development.

[0091] The viscosity can be measured using, for example, a viscoelasticity tester MCR-300 (trade name, manufactured by Pysica). One method for adjusting the viscosity within the above range is to appropriately adjust the types of the organic solvent and surfactant, and the amounts of these and water added.

[0092] (Young's modulus of dry coating film) The Young's modulus of the dried coating film of the white inkjet ink composition is preferably 20 MPa or less, more preferably 15 MPa or less, and even more preferably 10 MPa or less. When the Young's modulus of the dried coating film is within this range, when the coating film is formed on a stretchable recording medium, the coating film is more likely to follow the expansion and contraction of the recording medium. In other words, when the Young's modulus of the dried coating film is preferably 20 MPa or less, an image with even better conformability to the substrate can be formed.

[0093] The Young's modulus of the coating film obtained by drying the white inkjet ink composition can be measured as follows.

[0094] A silicone rubber frame (5 mm thick) was set on a stainless steel (SUS) plate, and 10 g of each ink composition or coating composition prepared above was placed in the 3 cm x 19 cm opening and allowed to dry overnight in the atmosphere. This was then heated at 160°C for 15 minutes to obtain a coating film on the SUS. The coating film was then peeled off from the SUS to obtain the coating film.

[0095] The stress-strain curve of the resulting coating was measured using a TENSILON universal testing machine (manufactured by A&D, product name: RTG-1250) under conditions of a test piece size of 10 mm wide, 30 mm high, and a tensile speed of 100 mm / min. The Young's modulus [MPa] was calculated by linear regression of the stress-strain curve between strains of 0.05 and 0.25%. The coating thickness required for this measurement was determined by actual measurement using a micrometer (manufactured by Mitutoyo, product name: MDH-25M).

[0096] 1.7.Effects According to the white inkjet ink composition of this embodiment, by using hollow resin particles as the white colorant, sedimentation of the white colorant can be effectively suppressed. Furthermore, when hollow resin particles are used, the structure is easily broken during heating and drying, resulting in a decrease in color development. However, by using hollow resin particles having a glass transition temperature of 120°C or higher, the decrease in color development can be suppressed. On the other hand, when hollow resin particles with a high glass transition temperature are used, the stretchability of the dried coating film of the white inkjet ink composition decreases, which can reduce its ability to conform to the recording medium (woven fabric). However, according to this white inkjet ink composition, by using resin particles other than the hollow resin particles that have a glass transition temperature of 5°C or lower, the ability to conform to the recording medium can also be improved. It can be made good.

[0097] 2. Inkjet recording method The inkjet recording method of this embodiment includes a white ink deposition step of ejecting the above-described white inkjet ink composition from a recording head and depositing it onto a recording medium.

[0098] According to the inkjet recording method of this embodiment, by using hollow resin particles as a white colorant, sedimentation of the white colorant can be effectively suppressed. Furthermore, when hollow resin particles are used, their structure is easily destroyed during heat drying, resulting in a decrease in color development. However, by using hollow resin particles having a glass transition temperature of 120°C or higher, the decrease in color development can be suppressed. Furthermore, according to this inkjet recording method, resin particles other than the hollow resin particles having a glass transition temperature of 5°C or lower are also used, so that an image with good conformability to the recording medium can be formed.

[0099] 2.1. Recording Media The recording medium may have a recording surface that absorbs liquid, or may not have a recording surface that absorbs liquid, and therefore is not particularly limited, and examples that can be used include paper, film, fabric, metal, glass, and polymers.

[0100] The material constituting the fabric is not particularly limited, and examples thereof include natural fibers such as cotton, linen, wool, and silk; synthetic fibers such as polypropylene, polyester, acetate, triacetate, polyamide, and polyurethane; and biodegradable fibers such as polylactic acid; and blends of these fibers are also possible.

[0101] Examples of the form of fabric include cloth, clothing, and other accessories. Fabrics include woven fabrics, knitted fabrics, nonwoven fabrics, and the like. Clothing and other accessories include sewn items such as T-shirts, handkerchiefs, scarves, towels, carrier bags, cloth bags, curtains, sheets, bedspreads, and wallpaper, as well as fabrics before and after cutting as parts before sewing. These may be in the form of long rolls, cut to a specified size, or in the shape of a finished product.

[0102] The basis weight of the fabric is not particularly limited, and may be 1.0 oz or more and 10.0 oz or less, preferably 2.0 oz or more and 9.0 oz or less, more preferably 3.0 oz or more and 8.0 oz or less, and even more preferably 4.0 oz or more and 7.0 oz or less. If the basis weight of the fabric is within this range, good recording can be performed. Furthermore, the inkjet recording method according to this embodiment can be applied to multiple types of fabrics with different basis weights, and good printing can be performed.

[0103] The fabric may be a cotton fabric that has been pre-colored with a dye. Examples of dyes that can be used to pre-color the fabric include water-soluble dyes such as acid dyes and basic dyes, disperse dyes that are used in combination with dispersants, and reactive dyes. When using a cotton fabric, it is preferable to use a reactive dye that is suitable for dyeing cotton.

[0104] Among these recording media, the recording medium is preferably a fabric, and preferably a fabric treated with a cationic compound. When recording on fabric using an ink containing hollow resin particles, even if the fabric has been treated with a component that causes the ink to aggregate, the hollow resin particles tend to penetrate into the interior of the fabric, making it difficult to achieve sufficient color development. However, the inkjet recording method according to this embodiment uses the white inkjet ink composition described above, and therefore can achieve excellent color development.

[0105] 2.2. Inkjet recording device The inkjet recording method of this embodiment can be carried out, for example, by filling an inkjet recording apparatus equipped with an ink container with the white inkjet ink composition. An example of an inkjet recording apparatus to which the white inkjet ink composition is applied will be described below.

[0106] The inkjet recording apparatus includes the above-described white inkjet ink composition, an ink container that contains the white inkjet ink composition, and a recording head that ejects the white inkjet ink composition. In the inkjet recording apparatus described below, the ink container has an ink inlet that can be opened and closed for filling with the white inkjet ink composition, but the present invention is not limited to this, and any inkjet recording apparatus may be used. In other words, the inkjet recording apparatus described below is an example of an apparatus that can be used to carry out the inkjet recording method of this embodiment.

[0107] The inkjet recording device will be described with reference to the drawings. The ink container serves as an ink tank for an inkjet printer (inkjet recording device) that records (prints) images or the like on a medium by ejecting ink onto the medium. In the following description, the inkjet recording device may be simply referred to as the recording device, and the white inkjet ink composition may be simply referred to as the ink.

[0108] As shown in FIG. 1, the recording device 21 includes a rectangular parallelepiped housing 22 with its longitudinal direction extending in the left-right direction. FIG. 1 also shows a simplified perspective view of the interior of the housing 22 of the recording device 21. A support base 23, with its longitudinal direction extending in the left-right direction, is provided in a lower portion toward the rear of the housing 22, with its upper surface aligned substantially horizontally. Paper P, an example of a medium, is supported on the upper surface of the support base 23 and transported forward in the transport direction. A guide shaft 24 extending in the left-right direction is installed above the support base 23 within the housing 22. A carriage 26, which includes a recording head 25 on its underside that ejects ink, is supported on the guide shaft 24. The carriage 26 is supported so as to be reciprocable in the left-right direction relative to the guide shaft 24, with the guide shaft 24 inserted through a support hole 27 that penetrates the housing in the left-right direction.

[0109] A drive pulley 28 and a driven pulley 29 are rotatably supported in positions near both ends of the guide shaft 24 within the housing 22. An output shaft of a carriage motor 30 is connected to the drive pulley 28, and an endless timing belt 31, a portion of which is connected to the carriage 26, is wound between the drive pulley 28 and the driven pulley 29. When the carriage 26 is driven by the carriage motor 30 and guided by the guide shaft 24 via the timing belt 31 to move back and forth along the left-right direction, which is the scanning direction for the paper P, ink is ejected from the recording head 25 on the underside of the carriage 26 onto the paper P, which is transported forward on the support base 23.

[0110] 1, a rectangular discharge opening 32 is opened at a position on the front side of the housing 22 in front of the support base 23, through which paper P, on which recording has been performed by ejecting ink from the recording head 25 as the paper is transported on the support base 23 within the housing 22, is discharged forward. A rectangular plate-shaped discharge tray 33 capable of supporting paper P discharged from the housing 22 is provided at the discharge opening 32 so as to be movable forward in the discharge direction. A paper feed cassette 34 capable of accommodating a plurality of sheets of paper P to be used for recording in a stacked state is attached below the discharge tray 33 within the discharge opening 32 so as to be removable in the front-to-rear direction.

[0111] 1, at a position on the front surface of the housing 22 closer to the left and right ends of the outlet 32 ​​(the right end in FIG. 1), a rectangular shape is formed on the front and top surfaces, and a right-angled triangle is formed on the right side surface. The door 35 is provided so as to be able to freely open and close in the front-rear direction around a rotation axis 36 provided at the bottom end of the door 35 and extending in the left-right direction. A window 37 made of a rectangular transparent member is formed on the front surface of the door 35, so that the user can see inside the housing 22 (particularly the back side of the front surface of the door 35) when the door 35 is closed.

[0112] An ink supply unit 40 that supplies ink to the recording head 25 is housed inside the housing 22 of the recording device 21 at a position behind the opening / closing door 35, that is, at a position closer to the front and closer to the end (closer to the right end in this case). The ink supply unit 40 is a structure that includes a plurality of (five in this embodiment) ink containers 41-45 and can be handled as a unit, and as will be described later, each of the ink containers 41-45 can be replenished with ink.

[0113] 2 and 3, the ink supply unit 40 includes five ink containers 41 to 45 each having a rectangular box shape that is elongated in the front-to-rear direction, five ink supply tubes 46 extending from the rear side of each ink container 41 to 45, and a rectangular parallelepiped ink supply adapter 47 to which the ink containers 41 to 45 are attached together. The ink supply adapter 47 is attached to stepped portions 48 cut out and formed in the upper front half portions of all the ink containers 41 to 45 when all the ink containers 41 to 45 are arranged side by side with their thicknesses aligned left to right, thereby integrating the ink containers 41 to 45. As shown in FIG. 1, the ink supply tubes 46 extending from the ink containers 41 to 45 are connected to ink flow paths (not shown) formed in the carriage 26 and are connected to the recording head 25 via the ink flow paths. The ink supply adapter 47 may be a part of the housing 22 that covers the ink containers 41-45, or may be formed integrally with the ink containers 41-45.

[0114] 4 and 5, the ink containers 41 to 45 each have an ink storage chamber 49 therein capable of storing an ink composition IK. In this embodiment, the ink storage chamber 49 of the ink container 41 located at the right end in the horizontal arrangement direction stores black ink. The ink storage chambers 49 of the other ink containers 42 to 45 arranged to the left of the right-end ink container 41 in the horizontal arrangement direction store inks of colors other than black (cyan, magenta, yellow, etc.). In addition, the ink containers 41 to 45 have a front wall portion visible through the window portion 37 on the front surface of the housing 22, on which a visibility portion 50 made of a transparent resin is provided, which enables the liquid level of the ink composition IK in the ink storage chamber 49 to be visible. The visible portion 50 is marked with an upper limit mark 51 indicating the upper limit of the liquid level of the ink composition IK stored in the ink storage chamber 49 (an example of an indication of the amount of ink that can be injected without the ink overflowing from the ink inlet 53), and a lower limit mark 52 indicating the lower limit (for example, an indication to encourage the refilling of ink).

[0115] As shown in FIG. 4, an ink inlet 53 (ink injection port) that can be opened and closed is provided above the horizontal portion of the stepped portion 48 in each of the ink containers 41-45, allowing ink to flow from the outside into the ink storage chamber 49. The ink inlet 53 includes a needle 56 that extends vertically upward and has flow paths 54, 55 that connect the inside of the ink storage chamber 49 to the outside. The flow paths 54, 55 of the needle 56 are composed of two flow paths 54, 55 arranged side by side in a radial direction with their tip openings centered on the needle 56. One of the two flow paths 54, 55 (the flow path 54 on the right side in FIG. 4) has a lower tip opening and a larger cross-sectional area than the other flow path 55 (the flow path 55 on the left side in FIG. 4). A remaining amount sensor 57 is provided at a lower rear portion of the ink storage chamber 49 to detect the remaining amount of ink composition IK in the ink storage chamber 49. The remaining amount sensor 57 is not required.

[0116] As shown in FIGS. 2 to 5, the ink supply adapter 47 has an upper surface 58 on which the needle 56 extends. The ink container 41 has a horizontal surface extending in a direction perpendicular to (intersecting with) the direction of extension, and a through-hole 60 is formed in its upper surface 58 as an ink inlet formation portion, penetrating vertically to a lower surface 59. The through-hole 60 is made up of a circular ink inlet 53 with a needle 56 located in the center, and a pair of rectangular holes connected to the front and rear of the ink inlet 53, and the lower opening is closed by the horizontal portion of the stepped portion 48 in the ink container 41-45 from which the needle 56 protrudes upward.

[0117] Therefore, in the through-hole 60, a pair of front and rear rectangular hole portions with their lower openings blocked form a pair of front and rear recesses 61 that open upward, in the direction in which the needle 56 extends, recessed in the depth direction vertically downward and symmetrically about the ink inlet 53. That is, in the ink refill adapter 47 integrated with the ink accommodating bodies 41 to 45, a plurality of recesses 61 (two pairs of front and rear recesses in this case) are formed that are point-symmetrical about the ink inlet 53 in the area outside the ink inlet 53 including the needle 56. In this case, the tip of the needle 56, which is located at the center of the circular ink inlet 53, is located closer to the ink storage chamber 49 than the top surface 58 of the ink refill adapter 47, which forms the opening edge of the through-hole 60 that includes the ink inlet 53 and the recesses 61. That is, the upper surface 58 of the ink supply adapter 47 extends in a direction intersecting the extension direction of the needle 56 at a position outside the tip of the needle 56 in the extension direction of the needle 56. On the other hand, the lower surface 59 of the ink supply adapter 47 functions as a tank engaging portion that collectively engages from above with the multiple ink containers 41 to 45 that are arranged side by side in the left-right direction.

[0118] Furthermore, the peripheral portion of the upper opening edge of each through hole 60 on the top surface 58 of the ink refill adapter 47 is colored a specific color. That is, it is colored the same color as the color of the ink stored in the ink storage chamber 49 of the ink accommodating body 41-45 into which ink flows via the ink inlet 53 of that through hole 60. In this regard, the peripheral portion of the upper opening edge of each through hole 60 in the ink refill adapter 47 functions as a first portion that externally indicates information related to the ink stored inside the ink accommodating body 41-45 whose ink inlet 53 of that through hole 60 communicates with the ink storage chamber 49. Incidentally, there are no particular restrictions on the ink stored in the ink containers 41 to 45, but if the ink container supplied from the ink container containing the ink composition of this embodiment is the ink container 41, it will store black or gray ink, and therefore the surrounding area of ​​the upper opening of the through hole 60, where the ink inlet 53 communicating with the ink storage chamber 49 of the ink container 41 is located, will be colored black or gray.

[0119] Furthermore, on the inner surface of the recess 61 (specifically, the inner surface along the vertical direction), a first uneven portion (first key structure portion) 62 having a characteristic uneven shape in the horizontal direction is provided at a position closer to the bottom surface than the upper opening edge of the recess 61 (i.e., closer to the horizontal portion of the stepped portion 48), so as to extend along the depth direction of the recess 61 (in other words, the direction of the central axis of the ink inlet 53). As shown in FIGS. 2 and 3 , the first uneven portion 62 is provided for each of the ink inlets 53 of the multiple (five in this embodiment) ink containers 41 to 45. Therefore, in the ink refill adapter 47, the rectangular recess 61 in each through hole 60 formed at a position corresponding to each of the ink containers 41 to 45 in the vertical direction has a first uneven portion 62 formed therein that is different from the first uneven portions 62 provided on the inner surface of the recess 61 of each of the other through holes 60. That is, these first uneven portions 62 function as identification portions that enable identification of ink bottles 63 (see FIG. 6, etc.) that have ink outlets 65 (see FIG. 6, etc.) that are connected to ink inlets 53 in through-holes 60 in which the first uneven portions 62 are formed. Note that "a position that is closer to the bottom than the upper opening edge of recess 61" means that it is sufficient that the position is set back slightly toward the bottom from the opening edge.

[0120] Next, the ink container 41 is used to configure an ink supply system together with the ink containers 41 to 45, and to supply ink to the ink containers 41 to 45 when the remaining amount of ink is low. Next, the ink bottle 63 will be described. The ink bottle 63 contains the white ink-jet ink composition described above.

[0121] 6 to 8, the ink bottle 63 comprises a cylindrical container body 64 that forms the main body of the ink bottle 63; an ink outlet forming portion 66 that is provided at the tip of the container body 64 and has an ink outlet 65 formed at its tip to allow ink to flow out of the ink bottle 63; and a container attachment portion 67 that is attached to the ink outlet forming portion 66 so as to surround the ink outlet 65. The ink outlet 65 of the ink outlet forming portion 66, together with the surrounding container attachment portion 67, is covered by a cylindrical cap 68 with a bottom, so that it is concealed from the outside when the ink bottle 63 is stored. That is, a male thread portion 69 is formed on the outer peripheral surface of the cylindrical lower end of the container attachment portion 67, while a female thread portion (not shown) is formed on the inner peripheral surface of the cap 68. By screwing the female thread portion of the cap 68 onto the male thread portion 69 of the container attachment portion 67, the cap 68 is attached to the tip of the ink bottle 63 so as to cover the ink outlet 65.

[0122] The entire outer surface of the container additional portion 67 is colored a specific color. That is, it is colored the same color as the ink contained in the container main body 64 to which the container additional portion 67 is attached. Incidentally, the outer surface of the container additional portion 67 of an ink bottle 63 containing black or gray ink is colored black or gray. Furthermore, multiple (four in this embodiment) protrusions 70 are formed at equal angular intervals (for example, 90-degree intervals) on the outer periphery of each base end of the container main body 64 and the cap 68. Incidentally, these protrusions 70 are formed to prevent the cylindrical ink bottle 63 from rolling. Furthermore, for example, the container main body 64 of an ink bottle 63 containing black ink may be formed thicker than the container main body 64 of an ink bottle 63 containing other colors of ink. In this case, the ink outlet forming portion 66 for black ink and the other colors of ink may have the same thickness and shape.

[0123] 6 to 8, above the cylindrical lower end where the male thread portion 69 is formed on the outer peripheral surface of the container attachment portion 67, a convex portion 71 is formed in an area outside the ink outlet 65 in the radial direction centered on the ink outlet 65. The convex portion 71 protrudes upward in the direction of the central axis of the ink outlet 65 in the opposite direction from the container main body 64 beyond the ink outlet 65. When the tip of the needle 56 on the ink inlet 53 side is inserted into the ink outlet 65, the convex portion 71 functions as a second fitting portion that can be fitted with the concave portion 61 on the upper surface 58 of the ink refill adapter 47 as the first fitting portion. The convex portion 71 is provided in a pair sandwiching the ink outlet 65 from the front and rear, similar to the pair of concave portions 61 that sandwich the ink inlet 53 from the front and rear. Note that, as shown in FIGS. 6 and 7, the convex portion 71 is formed inward from the outer peripheral surface of the container main body 64 in the radial direction centered on the ink outlet 65 of the ink bottle 63.

[0124] 6 and 9, the outer surface of each convex portion 71 (both left and right side surfaces in FIGS. 6 and 9) is formed with a second concave-convex portion (second key structure portion) 72 that can engage with a first concave-convex portion (first key structure portion) 62 formed on the inner surface of the concave portion 61 of the ink refill adapter 47. This second concave-convex portion 72 is provided to extend along the protruding direction of the convex portion 71 (in other words, the direction of the central axis of the ink outlet 65), and when the convex portion 71 is fitted into the concave portion 61 and the second concave-convex portion 72 is engaged with the first concave-convex portion 62, the ink outlet 65 of the ink bottle 63 is connected to the ink inlet 53 on the ink accommodating body 41-45 side.

[0125] Furthermore, a planar positioning portion 73 that is perpendicular to (intersects with) the central axis of the ink outlet 65 is provided between the cylindrical lower end of the container additional portion 67 where the male thread portion 69 is formed and the convex portion 71 where the second uneven portion 72 is formed, so as to be located radially outward from the ink outlet 65 when the ink outlet 65 is viewed in the direction of its central axis. In other words, this positioning portion 73 constitutes part of the outer surface of the container additional portion 67, which is part of the outer surface of the ink bottle 63, and is provided at a position closer to the container main body 64 than the tip of the convex portion 71 in the direction of the central axis of the ink outlet 65. Furthermore, since this positioning portion 73 is provided in the container attachment portion 67 that is attached to the ink outlet forming portion 66 in the ink bottle 63, it can be said that it is a separate member from the ink outlet forming portion 66 and is provided outside the ink outlet forming portion 66.

[0126] 9, a valve 74 made of an elastic material such as a silicone membrane is provided in the ink outlet 65 formed in the ink outlet forming portion 66, sealing the ink outlet 65 so that it can be opened and closed. The valve 74 is provided at a position where the positioning portion 73 is closer to the container main body 64 in the direction of the central axis of the ink outlet 65 (see, for example, FIG. 14). The valve 74 is provided with a plurality of slits 75 (three in this embodiment) that intersect at equal angular intervals (for example, 120-degree intervals) with the center of the valve 74 as the intersection point, and is configured to open when the slits 75 are pushed inward from the outside of the ink outlet 65. In other words, when the tip of the needle 56 on the ink inlet 53 side is inserted into the ink outlet 65, the normally closed valve 74 is pushed inward by the tip of the needle 56 and opens.

[0127] At this time, the positioning portion 73 comes into contact with the upper surface 58 of the ink refill adapter 47, in which the through-hole 60 including the ink inlet 53 and the recess 61 is formed, on the radial outside of the ink outlet 65, and positions the valve 74 with respect to the ink accommodating bodies 41 to 45 in the direction of the central axis of the ink outlet 65. In this regard, the upper surface 58 of the ink refill adapter 47 is part of the ink accommodating bodies 41 to 45 against which the positioning portion 73 of the ink bottle 63 comes into contact when the valve 74 of the ink outlet 65 of the ink bottle 63 is opened to replenish the ink accommodating bodies 41 to 45 with ink, and functions as a receiving surface that receives the planar positioning portion 73.

[0128] 10 and 11, the container body 64 of the ink bottle 63 is a bottle-shaped member having an ink chamber 76 therein capable of containing an ink composition IK, and a neck portion 77 at its upper end has an external thread portion 78 formed on the outer circumferential surface thereof. Meanwhile, the ink outlet forming portion 66 provided at the upper end of the container body 64 has a large diameter portion 79 located on the outer circumferential side of the neck portion 77 of the container body 64, a small diameter portion 80 forming the ink outlet 65 at a position furthest from the container body 64, and an intermediate portion 81 connecting the large diameter portion 79 and the small diameter portion 80. The ink outlet forming portion 66 is attached to the upper end of the container body 64 by threading a female thread portion 82 formed on the inner circumferential surface of the large diameter portion 79 into the male thread portion 78 formed on the outer circumferential surface of the neck portion 77 of the container body 64.

[0129] Furthermore, the container attachment portion 67, which is attached to the ink outlet forming portion 66 of the ink bottle 63 so as to surround the ink outlet 65, has a cylindrical lower end portion with a male thread portion 69 formed on its outer circumferential surface, which forms a joining portion 83 whose lower end surface is joined to the upper end surface of the large diameter portion 79 of the ink outlet forming portion 66. This joining portion 83 is joined to the large diameter portion 79 of the ink outlet forming portion 66 such that opposing surface areas in the front-to-rear direction of its inner circumferential surface are in surface contact with the front outer surface and the rear outer surface of the intermediate portion 81 of the ink outlet forming portion 66.

[0130] Next, the operation of the ink supply system configured as above will be described below, focusing on the operation when ink is supplied to the ink containers 41 to 45 of the ink supply unit 40 using the ink bottle 63.

[0131] As a premise, as shown in FIG. 2, the ink level in the ink container 41 for black ink, which is located at the far right among the ink containers 41 to 45 arranged side by side, has dropped to the height of the lower limit mark 52 marked at the bottom of the visible portion 50. Therefore, the following description will be given of the case where ink is replenished to this ink container 41. Also, it is assumed that the ink bottle 63 used for ink replenishment contains a sufficient amount of black ink, and that the cap 68 has been removed from the ink bottle 63 in advance. Furthermore, it is assumed that the shape of the second uneven portion 72 formed on the outer surface of the convex portion 71 of the ink bottle 63 is The shape of the protrusion 71 matches the shape of the first protrusion 62 formed on the inner surface of the recess 61 located before and after the ink inlet 53 to the ink container 41, and is capable of engaging with the recess 61 when the protrusion 71 is inserted into the recess 61.

[0132] When refilling the ink container 41 with ink, the user first rotates the open / close door 35 of the housing 22 from the closed state shown in Fig. 1 forward around the rotation shaft 36 to open it. Then, in the ink supply unit 40, the top surface 58 of the ink refill adapter 47, on which the ink inlet 53 leading to the ink containers 41 to 45 is formed, is exposed to the outside of the housing 22, and the user can connect the ink outlet 65 of the ink bottle 63 to the desired ink inlet 53 from above.

[0133] 12 and 13, the user turns the ink bottle 63 containing the ink composition to be used for ink refill upside down and holds it so that the ink outlet 65 is positioned above the rightmost through-hole 60 of the ink refill adapter 47. That is, the user aligns the central axis of the ink outlet 65 of the ink bottle 63 with the central axis of the ink inlet 53 of the ink container 41 to be refilled. At this time, the user compares the color (second portion) of the container attachment portion 67 of the ink bottle 63 being held with the color (first portion) of the periphery of the upper opening edge of the through-hole 60 where the ink inlet 53 of the ink container 41 to be refilled is provided. If the colors are the same (in this case, both are black), the user confirms that the ink bottle 63 being held is suitable for this ink refill and proceeds to the subsequent ink refill operation.

[0134] 12 and 13, the ink bottle 63 is lowered, and the protrusion 71 of the ink bottle 63 is inserted into the recess 61 of the ink refill adapter 47 that is integrated with the ink container 41. The insertion of the protrusion 71 into the recess 61 ensures that the central axis of the ink outlet 65 coincides with the central axis of the ink inlet 53. In this case, the recesses 61 are positioned point-symmetrically with respect to the needle 56, which is the center of the ink inlet 53, so the protrusion 71 can be inserted into either recess 61. Therefore, the user can easily insert the protrusion 71 into the recess 61 without having to repeatedly rotate the ink bottle 63 around the central axis of the ink outlet 65 to confirm the correct positional relationship between the recess 61 and the protrusion 71.

[0135] However, at this point, the protrusion 71 is only slightly inserted into the recess 61, and the tip of the needle 56 located at the center of the ink inlet 53 is inserted into the opening of the ink outlet 65, which protrudes slightly beyond the tip of the protrusion 71, but has not yet reached the valve 74 located deep inside the ink outlet 65. The reason for this is that, as shown in Figure 13, the distance L2 between the tip of the protrusion 71 and the valve 74 inside the ink outlet 65 is longer than the distance L1 between the top surface 58 of the ink refill adapter 47, where the edge of the opening of the recess 61 is located, and the upper end of the first uneven portion 62 inside the recess 61. Therefore, if the protrusion 71 is further inserted downward in the depth direction of the recess 61 from this state, the second uneven portion 72 on the outer surface of the protrusion 71 will engage with the first uneven portion 62 on the inner surface of the recess 61. Then, while maintaining this engagement, if the convex portion 71 is further inserted in the depth direction of the concave portion 61 toward the bottom side, the tip of the needle 56 of the ink inlet 53 will reach the position of the valve 74 of the ink outlet 65, opening the valve 74.

[0136] 14 and 15, the tip of the needle 56 pushes and widens the slit 75 from below to above (i.e., from the outside to the inside of the ink outlet 65) relative to the valve 74, thereby opening the valve 74. As a result, the ink outlet 65 of the ink bottle 63 and the needle 56 of the ink inlet 53 of the ink accommodating body 41 are connected, and the ink composition is replenished from the ink bottle 63 to the ink accommodating body 41. At this time, the needle 56 of the ink inlet 53 is connected to one of the two flow paths 54, 55, which allows the valve 74 to open and the ink to flow out of the ink outlet 65. The flow path that the tip opening touches first functions as an ink flow path for circulating ink, and the other flow path functions as an air flow path for circulating air. For example, if a user attempts to connect ink outlet 65 to ink inlet 53 while tilting ink bottle 63, the flow path that becomes the ink flow path will change depending on the tilt direction.

[0137] If the second uneven portion 72 does not engage with the first uneven portion 62 after inserting the protrusion 71 into the recess 61, the user will recognize at that point that they are inserting an ink bottle 63 of a color other than black. In this case, if the upper end of the first uneven portion 62 were positioned at the same height as the opening edge of the recess 61, not only would the second uneven portion 72 not be able to engage with the first uneven portion 62, but insertion of the protrusion 71 into the recess 61 would also be rejected. This could lead to the user repeatedly trying to insert the protrusion 71 into the recess 61, wasting time. In this regard, in the present embodiment, the height of the first uneven portion 62 is lower than the opening edge of the recess 61, so when the protrusion 71 is inserted into the recess 61, it is more likely to be guided toward the bottom in the depth direction of the recess 61, preventing the protrusion 71 from being unnecessarily long.

[0138] 14, 16, and 17, when the needle 56 of the ink inlet 53 on the ink accommodating body 41 side opens the valve 74 in the ink outlet 65 of the ink bottle 63, the positioning portion 73 of the ink bottle 63 abuts against the upper surface 58 of the ink refill adapter 47, which is part of the ink accommodating body 41 side. In other words, due to the abutment of this positioning portion 73 with the upper surface 58 of the ink refill adapter 47, the ink bottle 63 is opened with the valve 74 positioned relative to the needle 56 on the ink accommodating body 41 side in the direction of the central axis of the ink outlet 65.

[0139] Furthermore, at this time, because the positioning portion 73 is located radially outward of the ink outlet 65, the ink bottle 63 is stably maintained in a position with the ink outlet 65 connected to the ink inlet 53. Furthermore, as shown in Figures 14 and 15, when the positioning portion 73 of the ink bottle 63 abuts against the upper surface 58 of the ink refill adapter 47, a gap exists between the bottom surface of the ink inlet 53, where the base end of the needle 56 of the ink inlet 53 is located, and the tip of the ink outlet 65 of the ink bottle 63. Therefore, although ink tends to accumulate on the bottom surface of the ink inlet 53, where the base end of the needle 56 is located, this prevents the accumulated ink from adhering to the tip of the ink outlet 65 and soiling the ink bottle 63.

[0140] 14 and 16, when the ink replenishment from the ink bottle 63 to the ink container 41 is completed, if the ink level in the ink container 41 is still lower than the upper limit mark 51 of the visible portion 50, the same black ink bottle 63 may be used to further replenish the ink up to the upper limit mark 51. Note that the ink replenishment operation as described above is also performed in the same way for the ink containers 42 to 45 of other colors other than the ink container 41 containing the ink composition (black or gray ink composition).

[0141] The inkjet recording method of this embodiment can be easily carried out by ejecting the above-described white inkjet ink composition from the recording head of the above-described inkjet recording apparatus and depositing it onto a recording medium.

[0142] The step of depositing the white inkjet ink composition on a recording medium can be carried out using the inkjet recording apparatus described above. That is, the white inkjet ink composition is filled into a recording head so that it can be ejected from predetermined nozzles, and then ejected in that state onto a recording medium at predetermined timing, thereby depositing the white inkjet ink composition on a recording medium.

[0143] 2.3.Cationic Compound Treatment The inkjet recording method may include a step of treating a fabric with a cationic compound. The treatment method is not particularly limited, but the fabric can be treated with the cationic compound by applying a pretreatment agent containing a cationic compound to the fabric and drying it. Alternatively, the pretreatment agent may be applied using the inkjet recording apparatus described above.

[0144] [Pretreatment agent] When a pretreatment agent is used, it is sufficient that the pretreatment agent contains a cationic compound. The pretreatment agent may also contain resin particles, an organic solvent, water, and the like that can be contained in the white inkjet ink composition described above.

[0145] The cationic compound functions to aggregate components in the ink composition. Therefore, when the ink composition is applied to a fabric to which a pretreatment agent has been applied, the cationic compound promotes aggregation of ink particles and increases the viscosity of the ink, thereby suppressing absorption into the gaps or interior of the fibers that make up the fabric. In this way, the cationic compound retains the ink on the surface of the fabric, thereby improving the color development of the ink in the recorded material.

[0146] The cationic compound is not particularly limited, but examples thereof include metal salts, acids, cationic organic compounds, etc., and examples of the cationic organic compound that can be used include cationic resins (cationic polymers), cationic surfactants, etc. Among these, polyvalent metal salts are preferred as metal salts, and cationic resins are preferred as cationic organic compounds. Examples of acids include organic acids and inorganic acids, with organic acids being preferred. Therefore, it is preferred that the cationic compound be selected from cationic resins, organic acids, and polyvalent metal salts, as this will result in particularly excellent image quality, abrasion resistance, gloss, etc.

[0147] The metal salt is preferably a polyvalent metal salt, but metal salts other than polyvalent metal salts can also be used. Among these cationic compounds, it is preferable to use at least one selected from metal salts and organic acids because of their excellent reactivity with the components contained in the ink. It is also possible to use multiple types of cationic compounds in combination.

[0148] Polyvalent metal salts are compounds composed of divalent or higher metal ions and anions. Examples of divalent or higher metal ions include calcium, magnesium, copper, nickel, zinc, barium, aluminum, titanium, strontium, chromium, cobalt, and iron ions. Among the metal ions that compose these polyvalent metal salts, at least one of calcium ions and magnesium ions is preferred because they have excellent coagulation properties for ink components.

[0149] The anions constituting the polyvalent metal salt are inorganic or organic ions. That is, the polyvalent metal salt in the present invention is composed of an inorganic or organic ion and a polyvalent metal. Examples of such inorganic ions include chloride ions, bromide ions, iodide ions, nitrate ions, sulfate ions, and hydroxide ions. Examples of organic ions include organic acid ions, such as carboxylate ions.

[0150] The polyvalent metal compound is preferably an ionic polyvalent metal salt, and the stability of the pretreatment agent is improved particularly when the polyvalent metal salt is a magnesium salt or a calcium salt. The counter ion of the polyvalent metal may be either an inorganic acid ion or an organic acid ion.

[0151] Specific examples of the polyvalent metal salts include calcium carbonate such as heavy calcium carbonate and light calcium carbonate, calcium nitrate, calcium chloride, calcium sulfate, magnesium sulfate, calcium hydroxide, magnesium chloride, magnesium carbonate, barium sulfate, barium chloride, zinc carbonate, zinc sulfide, aluminum silicate, calcium silicate, magnesium silicate, Examples of suitable polyvalent metal salts include copper nitrate, calcium acetate, magnesium acetate, aluminum acetate, calcium propionate, magnesium propionate, aluminum propionate, calcium lactate, magnesium lactate, and aluminum lactate. These polyvalent metal salts may be used singly or in combination of two or more. Among these, at least one of magnesium sulfate, calcium nitrate, aluminum lactate, and calcium propionate is preferred in terms of achieving sufficient solubility in water. These metal salts may contain water of hydration in the raw material form.

[0152] Examples of metal salts other than polyvalent metal salts include monovalent metal salts such as sodium salts and potassium salts, such as sodium sulfate and potassium sulfate.

[0153] Suitable examples of organic acids include poly(meth)acrylic acid, acetic acid, propionic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, tartaric acid, lactic acid, sulfonic acid, orthophosphoric acid, pyrrolidonecarboxylic acid, pyronecarboxylic acid, pyrrolecarboxylic acid, furancarboxylic acid, pyridinecarboxylic acid, coumaric acid, thiophenecarboxylic acid, nicotinic acid, or derivatives of these compounds, or salts thereof. One organic acid may be used alone, or two or more organic acids may be used in combination. Salts of organic acids that are metal salts are included in the above-mentioned metal salts.

[0154] Examples of inorganic acids include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, etc. The inorganic acids may be used alone or in combination of two or more.

[0155] Examples of cationic resins (cationic polymers) include cationic urethane resins, cationic olefin resins, cationic amine resins, and cationic surfactants.

[0156] As the cationic urethane-based resin, commercially available products can be used, such as Hydran CP-7010, CP-7020, CP-7030, CP-7040, CP-7050, CP-7060, and CP-7610 (trade names, manufactured by Dainippon Ink and Chemicals, Inc.), Superflex 600, 610, 620, 630, 640, and 650 (trade names, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and Urethane Emulsion WBR-2120C and WBR-2122C (trade names, manufactured by Taisei Fine Chemical Co., Ltd.).

[0157] The cationic olefin resin has an olefin such as ethylene or propylene in its structural skeleton, and known resins can be appropriately selected and used. The cationic olefin resin may also be in an emulsion state dispersed in a solvent containing water or an organic solvent. Commercially available cationic olefin resins can be used, such as Arrowbase CB-1200 and CD-1200 (trade names, manufactured by Unitika Ltd.).

[0158] The cationic amine resin (cationic polymer) may be any resin having an amino group in its structure, and known resins may be appropriately selected and used. Examples include polyamine resins, polyamide resins, and polyallylamine resins. Polyamine resins are resins having amino groups in their main skeletons. Polyamide resins are resins having amide groups in their main skeletons. Polyallylamine resins are resins having a structure derived from allyl groups in their main skeletons.

[0159] Commercially available cationic amine resins include Unisense KHE103L (hexamethylenediamine / epichlorohydrin resin, 1% aqueous solution pH 5.0, viscosity 20-50 (mPa·s), 50% solids concentration) manufactured by Senka Corporation, and Unisense Examples of commercially available cationic polyamine resins include KHE104L (dimethylamine / epichlorohydrin resin, pH of 1% aqueous solution is about 7.0, viscosity is 1 to 10 (mPa·s), and solid content is 20% by mass). Specific examples of commercially available cationic polyamine resins include FL-14 (manufactured by SNF Corporation), Arafix 100, 251S, 255, and 255LOX (manufactured by Arakawa Chemical Co., Ltd.), DK-6810, 6853, and 6885; WS-4010, 4011, 4020, 4024, 4027, and 4030 (manufactured by Seiko PMC Corporation), and Papiogen P-105 (manufactured by Senka Co., Ltd.). , Sumirez Resin 650 (30), 675A, 6615, SLX-1 (manufactured by Taoka Chemical Co., Ltd.), Catiomaster (registered trademark) PD-1, 7, 30, A, PDT-2, PE-10, PE-30, DT-EH, EPA-SK01, TMHMDA-E (manufactured by Yokkaichi Synthetic Co., Ltd.), Jetfix 36N, 38A, 5052 (manufactured by Satoda Chemical Co., Ltd.).

[0160] Examples of allylamine resins include polyallylamine hydrochloride, polyallylamine amidosulfate, allylamine hydrochloride-diallylamine hydrochloride copolymer, allylamine acetate-diallylamine acetate copolymer, allylamine acetate-diallylamine acetate copolymer, allylamine hydrochloride-dimethylallylamine hydrochloride copolymer, allylamine-dimethylallylamine copolymer, polydiallylamine hydrochloride, polymethyldiallylamine hydrochloride, polymethyldiallylamine amidosulfate, polymethyldiallylamine acetate, polydiallyldimethylammonium chloride, diallylamine acetate-sulfur dioxide copolymer, diallylmethylethylammonium ethyl sulfate-sulfur dioxide copolymer, methyldiallylamine hydrochloride-sulfur dioxide copolymer, diallyldimethylammonium chloride-sulfur dioxide copolymer, diallyldimethylammonium chloride-acrylamide copolymer, and the like.

[0161] Examples of cationic surfactants include primary, secondary, and tertiary amine salt compounds, alkylamine salts, dialkylamine salts, aliphatic amine salts, benzalkonium salts, quaternary ammonium salts, quaternary alkylammonium salts, alkylpyridinium salts, sulfonium salts, phosphonium salts, onium salts, and imidazolinium salts. Specific examples include hydrochlorides and acetates of laurylamine, coconut amine, and rosinamine, lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, dimethylethyllaurylammonium ethyl sulfate, dimethylethyloctylammonium ethyl sulfate, trimethyllaurylammonium hydrochloride, cetylpyridinium chloride, cetylpyridinium bromide, dihydroxyethyllaurylamine, decyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium chloride, tetradecyldimethylammonium chloride, hexadecyldimethylammonium chloride, and octadecyldimethylammonium chloride. The cationic surfactant functions as a cationic compound, which will be described later, and may be contained in the ink composition. However, it is more preferable that the cationic surfactant be contained as a cationic compound in the pretreatment agent.

[0162] A plurality of these cationic compounds may be used. Furthermore, if at least one of polyvalent metal salts, organic acids, and cationic resins is selected from these cationic compounds, the aggregating action is more favorable, and therefore images of higher quality (particularly with better color development) can be formed.

[0163] The total content of the cationic compounds in the pretreatment agent is, for example, 0.1% by mass or more and 20% by mass or less, preferably 1% by mass or more and 20% by mass or less, and more preferably 2% by mass or more and 15% by mass or less, relative to the total mass of the pretreatment agent. Even when the cationic compounds are used in a solution or dispersion, the solid content is preferably within the above range. When the content of the cationic compounds is 1% by mass or more, the cationic compounds can be easily dissolved in the pretreatment agent. The cationic compound content of the pretreatment agent is 30% by mass or less, which results in a satisfactory ability of the compound to aggregate the components contained in the ink. Furthermore, by keeping the content of the cationic compound at 30% by mass or less, the solubility and dispersibility of the cationic compound in the pretreatment agent are improved, thereby improving the storage stability of the pretreatment agent.

[0164] [Method of applying pretreatment agent] The application method is not particularly limited as long as it can adhere the pretreatment agent to at least a partial region of the fabric. Examples of application methods include dip coating, in which the fabric is immersed in the pretreatment agent; roller coating, in which the pretreatment agent is applied using a brush, roller, spatula, roll coater, or the like; spray coating, in which the pretreatment agent is sprayed using a spray device, or the like; and inkjet coating, in which the pretreatment agent is applied by an inkjet method. Among these, dip coating, roller coating, spray coating, and the like are preferred, as they require a simple device configuration and allow for rapid application of the pretreatment agent.

[0165] The amount of pretreatment agent to be applied is not particularly limited, but when fabric is used as the recording medium, it is preferable to apply 5 to 30 g, more preferably 10 to 25 g, and even more preferably 15 to 25 g per A4 size area.

[0166] [Drying method] The drying method is not particularly limited, but examples thereof include drying using a hot press machine, an oven, etc. The heating temperature is preferably 100°C or higher, more preferably 110 to 200°C, and even more preferably 120 to 180°C. The heating time is preferably within 2 minutes. When the heating temperature is 100°C or higher, the fixability of the cationic compound tends to be improved. When a hot press machine is used, the pressing pressure is not particularly limited, but is preferably 3.0 to 5.0 N / cm. 2 It is preferable to do this to an extent.

[0167] 2.4.Heat drying process The inkjet recording method according to this embodiment may include a step of heating and drying the ink that has been applied to the recording medium, after the white ink application step.

[0168] The heat drying method is not particularly limited, but examples thereof include a heat press method, an atmospheric pressure steam method, a high pressure steam method, a Thermofix method, etc. The heat source for heat drying is not particularly limited, but for example, an infrared lamp or the like can be used.

[0169] The heat drying temperature is preferably a temperature at which the resin particles of the ink are fused and the medium, such as water, volatilizes. For example, a temperature of about 100°C or higher and about 200°C or lower is preferable, 180°C or lower is more preferable, and 160°C or lower is even more preferable. Here, the heat drying temperature in the heat drying step refers to the surface temperature of the image formed on the recording medium. The time for heat drying is not particularly limited, but is preferably, for example, 30 seconds to 20 minutes, and more preferably 5 minutes to 10 minutes.

[0170] It is more preferable that the maximum temperature of the recording medium in the heat-drying step is 180°C or less and that the duration of the heat-drying step is 10 minutes or less. This allows for faster image formation while maintaining good color development of the white image. The duration of the heat-drying step refers to the time during which the recording medium is heated by the heat source.

[0171] 2.5.Other processes The inkjet recording method according to this embodiment may further include, after the heat drying step, a step of rinsing the printed recording medium with water, and a step of again rinsing with heat. If necessary, during the water washing step, components of the ink and the like that have not been fixed to the recording medium may be washed away using a hot soapy solution or the like as a soaping treatment.

[0172] 3. Working Example The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" below is based on mass.

[0173] 3.1. Preparation of White Inkjet Ink Composition The components were placed in a container so as to obtain the compositions shown in Tables 1 and 2, and mixed and stirred for 2 hours using a magnetic stirrer. The mixture was then filtered through a membrane filter with a pore size of 5 μm to obtain white inkjet ink compositions according to Examples and Comparative Examples. Unless otherwise specified, the numerical values ​​in the tables represent the content in mass %. The content of the colorant and resin particles represents the content converted into solid content.

[0174] [Table 1]

[0175] [Table 2]

[0176] The abbreviations and footnotes in Tables 1 and 2 are as follows: Titanium dioxide slurry: anionic; average particle size 400nm Dispersion A: Preparation Example 1 below; Tg = 124°C; styrene-acrylic resin; anionic; average particle size 280 nm SX868B: JSR Corporation; Tg = 109°C; styrene-acrylic resin; anionic; average particle size 500 nm V1004: Zeon Corporation; Tg = 87°C; styrene-acrylic resin; anionic; average particle size 314 nm Dispersion B: Preparation Example 2 below; Tg = 131°C; styrene-acrylic resin; anionic; average particle size 700 nm Movinyl 6899D; Nippon Synthetic Chemical Industry Co., Ltd.; Tg=46°C; acrylic resin; anionic Movinyl 6718; Nippon Synthetic Chemical Industry Co., Ltd.; Tg=3°C; acrylic resin; anionic Movinyl 6751D; Nippon Synthetic Chemical Industry Co., Ltd.; Tg = -32°C; acrylic resin; anionic Superflex 820: Daiichi Kogyo Seiyaku Co., Ltd.; Tg = 46°C; urethane resin; anionic Superflex 740; Daiichi Kogyo Seiyaku Co., Ltd.; Tg=-34°C; urethane resin; anionic Glycerin: Standard boiling point 290℃ Triethylene glycol: Standard boiling point 287°C 3-Methyl-1,3-butanediol: Standard boiling point 203°C 1,3-Butanediol normal boiling point 203℃ BYK348: BYK; polyether-modified organosiloxane Dispersion A: Preparation Example 1 below; Tg = 124°C; styrene-acrylic resin; anionic; average particle size 280 nm Superflex 500M; Daiichi Kogyo Seiyaku Co., Ltd.; Tg=-39°C; urethane resin; nonionic In addition to the evaluation results, Table 1 also lists the difference in Tg between the hollow resin particles and the resin particles.

[0177] 3.2.Evaluation Method 3.2.1. Preparation of Dispersion Dispersions A and B of hollow resin particles were prepared as follows. <Production Example 1> (1) Synthesis of seed particle emulsion A four-neck separable flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 726.0 parts by mass of deionized water, 5.0 parts by mass of methyl methacrylate, and 0.1 parts by mass of methacrylic acid, and heated with stirring. Next, when the internal temperature of the separable flask reached 70°C, 1.0 part by mass of a 10% by mass aqueous solution of ammonium persulfate was added, and the mixture was heated at 80°C for 20 minutes.

[0178] Separately, 141.0 parts by mass of methyl methacrylate, 94.9 parts by mass of methacrylic acid, 5.0 parts by mass of sodium alkylbenzenesulfonate (Neogen SF-20, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as an anionic emulsifier, and 120.0 parts by mass of deionized water were emulsified using a Homodisper to form a pre-emulsion, which was then charged into a dropping funnel.

[0179] Next, while maintaining the internal temperature of the separable flask at 80°C, the pre-emulsion obtained above was added dropwise uniformly over 3 hours, and simultaneously 10.0 parts by mass of a 10% by mass aqueous solution of ammonium persulfate was added dropwise uniformly over 3 hours. After completion of the addition, the mixture was aged at 80°C for 3 hours, cooled, and then filtered using a 120-mesh filter cloth to obtain a seed particle emulsion.

[0180] (2) First-stage polymerization A four-neck separable flask equipped with a stirrer, thermometer, condenser, and dropping funnel was charged with 188.2 parts by mass of deionized water, and 66.0 parts by mass of the seed particle emulsion obtained above was added dropwise, followed by heating to 80° C. with stirring. Meanwhile, 2.4 parts by mass of butyl acrylate, 1.1 parts by mass of butyl methacrylate, 19.5 parts by mass of methyl methacrylate, 0.7 parts by mass of methacrylic acid, 5.0 parts by mass of sodium alkylbenzenesulfonate (Neogen SF-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 55.3 parts by mass of deionized water were emulsified with a Homodisper to form pre-emulsion 1, which was then charged into the dropping funnel.

[0181] Next, while maintaining the internal temperature of the separable flask at 80°C, the pre-emulsion 1 obtained above was added dropwise uniformly over 30 minutes, and at the same time, a 10% by mass aqueous solution of sodium persulfate was added dropwise. 1.2 parts by mass of the solution was added dropwise evenly over 30 minutes.

[0182] (3) Second-stage polymerization 20.5 parts by mass of styrene, 0.5 parts by mass of 1,3-diethylbenzene, 5.0 parts by mass of sodium alkylbenzenesulfonate (Neogen SF-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 51.8 parts by mass of deionized water were emulsified using a Homodisper to form pre-emulsion 2, which was then charged into a dropping funnel.

[0183] Next, while maintaining the internal temperature of the separable flask at 80°C, one hour after the completion of the dropwise addition of pre-emulsion 1, pre-emulsion 2 obtained above was added dropwise uniformly over 60 minutes, and simultaneously, 3.5 parts by mass of a 10% by mass aqueous solution of sodium persulfate was added dropwise uniformly over 60 minutes.

[0184] After the dropwise addition of pre-emulsion 2 was completed, 7.5 parts by mass of 28% by mass ammonia water was added dropwise to swell and dissolve the seed particles, and the mixture was aged for 1 hour at 80° C. After cooling, the mixture was filtered using a 120-mesh filter cloth to obtain hollow resin dispersion A.

[0185] <Production Example 2> A hollow resin dispersion B was obtained in the same manner as in Production Example 1 above, except that the amount of styrene in the second-stage polymerization was 60.1 parts by mass.

[0186] 3.2.2. Fabric pretreatment The fabric to be treated was a Hanes T-shirt (black, 100% cotton) and 15 to 20 g of the pretreatment agent from each example and comparative example was sprayed onto it, and then the pretreatment agent was applied to the fabric using a heat press machine (Itsumi SF-54TEN) at a pressure of 4.2 N / cm. 2 The fabric was dried at 130°C for 1 minute so that the temperature became 25°C, and then returned to 25°C to obtain a treated fabric.

[0187] The pretreatment agent was formulated as an aqueous solution in which calcium chloride dihydrate was dissolved in pure water as a cationic compound, and the following treatment liquid compositions 1 to 3, which differed in calcium chloride dihydrate concentration, were used. Treatment liquid composition 1: 9.0 mass% Treatment liquid composition 2: 6.0 mass% Treatment liquid composition 3: 3.0 mass% In addition, in the examples and comparative examples in Table 1, processing liquid composition 2 was used. In Table 2, the processing liquid composition shown in Table 2 was used for each example. The amount of pretreatment agent applied was 15 g / A4 in all cases.

[0188] 3.2.3. Recording method A recording device, SC-F2000 manufactured by Seiko Epson Corporation, was prepared. The white inkjet ink composition of each Example and Comparative Example was filled in, and images described in each evaluation method were printed on the pretreated fabric described above or in the table. The amount of the white inkjet ink composition applied was 100 mg / inch in all examples. 2 It was decided.

[0189] 3.2.4. Evaluation of Whiteness L* after Heat Drying A white inkjet ink composition that had been thoroughly stirred to restore sedimentation was applied by inkjet to the fabric pretreated by the above method, and then subjected to a heat drying treatment at 150°C for 5 minutes using a conveyor drying oven (Economax D conveyor drying oven, manufactured by M&R). The printed fabric was then immersed in 2 L of water at 25°C, and washed for 5 minutes by shaking the container once every 2 seconds. The water was then removed with a towel, and the printed fabric was then subjected to a heat drying treatment at 150°C for 5 minutes. L* was then measured using a colorimeter (Spectrolino, manufactured by Gretag), and the following criteria were calculated: The results were evaluated according to the standard and are shown in the table. S:85≦L* A:70≦L*<85 A-:60≦L*<70 B:L*<60

[0190] 3.2.5. Evaluation of fabric conformability (cotton T-shirt fabric) The ink composition, which had been thoroughly stirred to restore sedimentation, was then ink-jet coated onto the fabric pretreated as described above at the ink deposition amount specified in the Examples. The ink composition was then heated and dried at 150°C for 5 minutes using a conveyor drying oven (Economax D conveyor drying oven, manufactured by M&R). The printed fabric was then allowed to stand and returned to 25°C, after which a 3 x 15 cm piece of fabric was prepared. With one side of the fabric piece fixed, it was stretched 5 cm in the longitudinal direction, and the state of the printed image was visually observed and evaluated according to the following criteria. The results are shown in the table. A: No cracks in the image B: Cracks in the image

[0191] 3.2.6.Evaluation of Discharge Reliability Each white inkjet ink composition was filled into a color ink cartridge of the recording device described above, and a nozzle check image was printed on a transparent PET film using the SC-F2000's built-in nozzle check function. After confirming that the nozzle check image was printed correctly and that ink was ejecting normally from all nozzles, the automatic head cleaning function was turned off, and the printer was left standing for 15 minutes in an environment at room temperature of 25°C and relative humidity of 40% without the drying prevention caps attached to the head nozzles. The printer was then left standing for another 24 hours with the drying prevention caps attached. After that, a nozzle check image was printed again, and the number of nozzles for which the nozzle check image was not printed was counted. The results were evaluated according to the following criteria and listed in the table. If any nozzles were missing, a recovery operation was performed 1 to 5 times using the SC-F2000's built-in head cleaning function, and a nozzle check image was printed and the number of missing nozzles was counted. The results were evaluated according to the following criteria and listed in the table. S: No missing nozzles A: Nozzle missing, but no nozzle missing after one recovery operation A-: Nozzle missing, but no nozzle missing within 5 recovery operations B: Nozzle missing, and nozzle missing still occurs after performing recovery operation five times

[0192] 3.2.7. Evaluation of pigment sedimentation rate After thorough stirring to remove any sedimentation, 100 mL of each white inkjet ink composition was poured into a glass screw cap vial (110 cc lab screw cap vial, manufactured by AS ONE Corporation). A 5 mL sample was then pipetted at 10 mm below the ink surface to serve as a pre-test sample. The screw cap vial was then left to stand at 20°C. After 168 hours, 5 mL of ink was again pipetted at 10 mm below the ink surface to serve as a post-test sample. The pre-test and post-test samples were thoroughly stirred to remove any sedimentation, and 0.5 mg of each sample was pipetted. The sample was diluted with pure water in a 1-L volumetric flask to prepare a 1-L diluted solution. The absorbance (Abs) was measured using a spectrophotometer (U-3900H, manufactured by Hitachi High-Tech Science Corporation). The percentage change in absorbance was then calculated using the following formula, and the results were evaluated according to the following criteria. The results are listed in the table. Percentage change in absorbance: {(Abs after test) - (Abs before test)} / (Abs before test) x 100 A: -5% or more B: Less than -5%

[0193] 3.2.8. Measurement of Young's modulus of dried ink coating A silicone rubber frame (thickness: 5 mm) was set on a stainless steel (SUS) plate, and 10 g of each ink composition prepared above was placed in the opening (3 cm x 19 cm) and dried overnight in the atmosphere. The plate was then heated at 160°C for 15 minutes to obtain a coating film on the SUS plate. The coating film was then peeled off from the SUS plate to obtain a coating film.

[0194] The stress-strain curve of the resulting coating was measured using a TENSILON universal testing machine (manufactured by A&D Corporation, product name: RTG-1250) under conditions of a test piece size of 10 mm wide, 30 mm high, and a tensile speed of 100 mm / min. The Young's modulus [MPa] was calculated by linear regression of the stress-strain curve between strains of 0.05 and 0.25%. The coating thickness required for this measurement was determined by actual measurement using a micrometer (manufactured by Mitutoyo Corporation, product name: MDH-25M). The Young's modulus of the coating film obtained by drying each white inkjet ink composition is shown in the table.

[0195] 3.2.9. Difference between Tg of hollow resin particles and Tg of resin particles The glass transition temperatures of the hollow resin particles and resin particles used in each example were determined using a differential scanning calorimeter "DSC7000" manufactured by Hitachi High-Tech Science Corporation in accordance with the glass transition temperature measurement method for plastics JIS K7121, and the differences are shown in the table.

[0196] 3.2.10. Evaluation of bleeding after heat drying A gradation pattern (patch size: 1 x 1 cm, 10 gradations (20-200%), patch spacing: 0.25 mm) was printed in four rows at 0.25 mm intervals on the fabric pretreated using an inkjet device (SC-F2000). The pattern was then subjected to a heat drying treatment at 150°C for 5 minutes using a conveyor drying oven (M&R Economax D conveyor drying oven). The boundaries of each patch were checked under a microscope, and if the boundaries between the patches had disappeared due to bleeding, the pattern was judged to be unacceptable. The results were evaluated according to the following criteria and listed in the table. S: Pass up to Duty 200% A: Duty 100% or more but less than 200% fails B: Duty less than 100% failed

[0197] 3.3.Evaluation Results The white inkjet ink compositions of the examples, which contain hollow resin particles, resin particles, and water, and in which the hollow resin particles have a glass transition temperature of 120°C or higher and the resin particles have a glass transition temperature of 5°C or lower, were found to have good color development (whiteness L*), storage stability (pigment sedimentation rate), and image conformability to fabric.

[0198] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

[0199] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations that replace non-essential parts of the configurations described in the embodiments. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations that add publicly known technology to the configurations described in the embodiments.

[0200] The following can be derived from the above-described embodiment and modifications.

[0201] The white inkjet ink composition comprises Contains hollow resin particles, resin particles, and water, The glass transition temperature of the hollow resin particles is 120°C or higher, The resin particles have a glass transition temperature of 5° C. or lower.

[0202] This white inkjet ink composition uses hollow resin particles as a white colorant, thereby effectively suppressing settling of the white colorant. Furthermore, when hollow resin particles are used, their structure is prone to break down during heat drying, resulting in a decrease in color development. However, by using hollow resin particles with a glass transition temperature of 120°C or higher, this decrease in color development can be suppressed. On the other hand, the use of hollow resin particles with a high glass transition temperature can reduce the stretchability of the dried coating film of the white inkjet ink composition, resulting in a decrease in conformity to the recording medium (woven fabric). However, this white inkjet ink composition can also improve conformity to the recording medium by using resin particles other than the hollow resin particles that have a glass transition temperature of 5°C or lower.

[0203] In the white inkjet ink composition, The hollow resin particles may contain an acrylic resin.

[0204] This white inkjet ink composition makes it easy to produce hollow resin particles having a glass transition temperature of 120° C. or higher, and also makes it easier to adjust the glass transition temperature.

[0205] In the white inkjet ink composition, The resin particles may contain any one selected from a urethane-based resin and an acrylic-based resin.

[0206] This white inkjet ink composition can form images with even better fabric conformability.

[0207] In the white inkjet ink composition, The resin particles may have a glass transition temperature of −35° C. or higher.

[0208] This white inkjet ink composition can further improve the storage stability of the white inkjet ink composition.

[0209] In the white inkjet ink composition, The white inkjet ink composition may have a Young's modulus of 20 MPa or less when dried.

[0210] This white inkjet ink composition can form images with even better fabric conformability.

[0211] In the white inkjet ink composition, At least one of the resin particles and the hollow resin particles may contain an anionic resin.

[0212] When the white inkjet ink composition comes into contact with a cationic compound, at least one of the resin particles and the hollow resin particles tends to aggregate, making it possible to obtain images with even better image quality.

[0213] In the white inkjet ink composition, The water-soluble organic solvent further contains an alkanediol having a normal boiling point of 240°C or less, The alkanediol is an alkanediol having 4 to 6 carbon atoms and at least one hydroxyl group bonded to a position other than the terminal of the alkane chain, The content of the alkanediol having a normal boiling point of 240° C. or less may be 75.0% by mass or more based on the total amount of the water-soluble organic solvent.

[0214] This white inkjet ink composition can suppress a decrease in the whiteness of a white image formed on a recording medium, even when the white image is quickly dried by heating.

[0215] In the white inkjet ink composition, The absolute value of the difference between the glass transition temperature of the hollow resin particles and the glass transition temperature of the resin particles may be 125° C. or more.

[0216] This white inkjet ink composition can improve the color development of images and also improve the conformability to the fabric.

[0217] The inkjet recording method is The method includes a white ink deposition step of ejecting the white inkjet ink composition from a recording head and depositing it onto a recording medium.

[0218] According to this inkjet recording method, hollow resin particles are used as a white coloring material, thereby effectively suppressing settling of the white coloring material. Furthermore, when hollow resin particles are used, their structure is easily destroyed during heat drying, resulting in a decrease in color development. However, by using hollow resin particles having a glass transition temperature of 120°C or higher, the decrease in color development can be suppressed. Furthermore, according to this inkjet recording method, resin particles other than the hollow resin particles having a glass transition temperature of 5°C or lower are also used, thereby enabling the formation of images with good conformability to the recording medium.

[0219] In the inkjet recording method, The inkjet recording method, wherein the recording medium is a fabric.

[0220] According to this inkjet recording method, an image can be formed that has good conformability to fabric.

[0221] In the inkjet recording method, The method further includes a heating step of heating the recording medium after the white ink applying step, The maximum temperature of the recording medium in the heating step may be 180° C. or less, and the duration of the heating step may be 10 minutes or less.

[0222] According to this inkjet recording method, it is possible to form an image at a higher speed while maintaining good color development of the white image. [Explanation of symbols]

[0223] 21...recording device, 22...casing, 23...support base, 24...guide shaft, 25...recording head, 26...carriage, 27...support hole, 28...drive pulley, 29...driven pulley, 30...carriage motor, 31...timing belt, 32...discharge outlet, 33...discharge tray, 34...paper feed cassette, 35...opening / closing door, 36...rotating shaft, 37...window portion, 40...ink supply unit, 41-45...ink container, 46...ink supply tube, 47...ink refill adapter, 48...step portion, 49...ink storage chamber, 50...visible portion, 51...upper limit mark, 52...lower limit mark, 53...ink inlet, 54, 55...flow path, 56...needle (ink inlet flow path portion), 57...remaining amount sensor, 58...upper surface (receiving surface), 59...lower surface (tank engagement portion), 60...through hole, 61...recess portion (first fitting portion), 62...first uneven portion (identification portion), 63...ink bottle, 64...container main body portion, 65...ink outlet, 66...ink outlet forming portion, 67...container additional portion, 68...cap, 69...male thread portion, 70...projection, 71...convex portion (second fitting portion), 72...second uneven portion, 73...positioning portion, 74...valve, 75...slit, 76...ink storage chamber, 77...neck portion, 78...male thread portion, 79...large diameter portion, 80...small diameter portion, 81...middle portion, 82...female thread portion, 83...joint portion, L1...distance, L2...distance, P...paper, IK...ink composition

Claims

1. The composition contains hollow resin particles, resin particles, water, and a water-soluble organic solvent, The glass transition temperature of the hollow resin particles is 120°C or higher, the glass transition temperature of the resin particles is 5°C or less, the water-soluble organic solvent contains an alkanediol having a normal boiling point of 240°C or less, the alkanediol is selected from 3-methyl-1,3-butanediol, 1,3-butanediol and 2-methyl-2,4-pentanediol; the content of the alkanediol having a normal boiling point of 240°C or less is 75.0% by mass or more relative to the total amount of the water-soluble organic solvent.

2. In claim 1, The white inkjet ink composition, wherein the hollow resin particles comprise an acrylic resin.

3. In claim 1 or claim 2, The white inkjet ink composition, wherein the resin particles contain any one selected from a urethane-based resin and an acrylic-based resin.

4. In any one of claims 1 to 3, The white inkjet ink composition, wherein the resin particles have a glass transition temperature of −35° C. or higher.

5. In any one of claims 1 to 4, The white inkjet ink composition, wherein the Young's modulus of a dried coating film of the white inkjet ink composition is 20 MPa or less.

6. In any one of claims 1 to 5, At least one of the resin particles and the hollow resin particles comprises an anionic resin.

7. In any one of claims 1 to 6, the absolute value of the difference between the glass transition temperature of the hollow resin particles and the glass transition temperature of the resin particles is 125° C. or more.

8. An inkjet recording method comprising: a white ink deposition step of ejecting the white inkjet ink composition according to claim 1 from a recording head and depositing it onto a recording medium.

9. In claim 8, The inkjet recording method, wherein the recording medium is a fabric.

10. In claim 8 or claim 9, The method further includes a heating step of heating the recording medium after the white ink applying step, The inkjet recording method, wherein the maximum temperature of the recording medium in the heating step is 180° C. or less.

Images