Printing method and printing device

Abstract

To provide a printing method which has a high image quality and excellent discharge stability, even on a permeable printed matter.SOLUTION: A printing method includes a first drying step of heating a surface to which ink is not discharged, and drying the ink, and a second drying step of heating the surface to which the ink is discharged and drying the ink, wherein a heating temperature T1(°C) of the first drying step and a heating temperature T2(°C) of the second drying step satisfy Equality (1): 0(°C)≤T2-T1≤90(°C), the ink contains an organic solvent A having a boiling point of lower than 250°C and an organic solvent B having a boiling point of 250°C or higher, a content of the organic solvent A is 30 mass% or less, a content of the organic solvent B is 1 mass% or more and 3 mass% or less, and a content of the resin with respect to the ink is 5 mass% or more and 15 mass% or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a printing method and a printing device. [Background technology]

[0002] Inkjet printing has been rapidly gaining popularity in recent years because it allows for easy recording of color images and has low running costs. A wide variety of substrates are used for printing, including papers such as plain paper and glossy paper, as well as cloth and fabric made of fibers, such as knitted fabrics, woven fabrics, and nonwoven fabrics (see, for example, Patent Document 1). Many of these printing substrates are permeable, but when printing on a permeable substrate, the coloring material contained in the ink permeates into the substrate, making it difficult to obtain color development. One method for improving color development on permeable printing substrates is to increase the viscosity of the ink (see, for example, Patent Document 2). Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present invention is to provide a printing method that provides high image quality even on a permeable printing substrate and has excellent ejection stability. [Means for solving the problem]

[0004] As a means for solving this problem, the printing method of the present invention comprises the steps of: A discharge step of discharging ink onto a substrate; a first drying step of heating a surface of the printing substrate on which the ink is not ejected to dry the ink; a second drying step of heating the surface of the printing substrate onto which the ink has been ejected to dry the ink; the heating temperature T1 (°C) in the first drying step and the heating temperature T2 (°C) in the second drying step satisfy inequality (1); 0(℃)≦T2-T1≦90(℃)...Inequality (1) the ink contains an organic solvent A having a boiling point of less than 250° C., an organic solvent B having a boiling point of 250° C. or more, and a resin; The content of the organic solvent A is 30% by mass or less, The content of the organic solvent B is 1% by mass or more and 3% by mass or less, The content of the resin in the ink is 5% by mass or more and 15% by mass or less, the viscosity of the ink at 25°C is 8.0 mPa s or more and 11.0 mPa s or less; the viscosity of the ink at 36°C is 5.5 mPa s or more and 11.0 mPa s or less; The ink droplets having a volume of 2.5 μL ejected onto the substrate are characterized in that the time required for the volume of the droplets to decrease to a volume of 0.1 μL or less is 10.0 seconds or less at 25° C. Effect of the Invention

[0005] According to the present invention, it is possible to provide a printing method that provides high image quality even on a permeable printing substrate and has excellent ejection stability. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view showing a schematic diagram of an example of a printing apparatus of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a schematic view of a main tank in the printing apparatus of the present invention. [Diagram 3] FIG. 3 is a schematic diagram showing an example of the configuration of a printing device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] (Printing method) The printing method of the present invention includes a discharge step of discharging ink onto a substrate, a first drying step of heating a surface of the substrate onto which the ink has not been discharged to dry the ink, and a second drying step of heating a surface of the substrate onto which the ink has been discharged to dry the ink, wherein a heating temperature T1 (°C) of the first drying means and a heating temperature T2 (°C) of the second drying means satisfy inequality (1). 0(℃)≦T2-T1≦90(℃)...Inequality (1) The ink in the printing method of the present invention contains an organic solvent A having a boiling point of less than 250° C., an organic solvent B having a boiling point of 250° C. or more, and a resin, The content of the organic solvent A is 30% by mass or less, The content of the organic solvent B is 1% by mass or more and 3% by mass or less, The content of the resin is 5% by mass or more and 15% by mass or less, the viscosity of the ink at 25°C is 8.0 mPa s or more and 11.0 mPa s or less; the viscosity of the ink at 36°C is 5.5 mPa s or more and 11.0 mPa s or less; The time required for a droplet of the ink having a volume of 2.5 μL ejected onto the substrate to reduce in volume to 0.1 μL or less is 10.0 seconds or less at 25° C.

[0008] In the method of Prior Art Document 2 (JP Patent Publication 2005-144966 A), the ink is made highly viscous, which makes the ink more likely to stick to the nozzle surface, resulting in problems such as reduced ejection stability and reduced drying properties after the ink is printed on a substrate. Furthermore, the ink is more likely to remain on the substrate, which reduces abrasion resistance.

[0009] The printing method of the present invention is based on the finding that an optimal combination of ink and system can achieve high image quality and ejection stability on permeable substrates, which could not be achieved with conventional inks and printing devices using ink.

[0010] The printing method of the present invention comprises an ejection step of ejecting ink onto a substrate, a first drying step of heating a surface of the substrate onto which the ink has not been ejected to dry the ink, and a second drying step of heating a surface of the substrate onto which the ink has been ejected to dry the ink, and may further comprise other steps as necessary. In the printing method of the present invention, the heating temperature T1 (°C) in the first drying step and the heating temperature T2 (°C) in the second drying step satisfy inequality (1). When T2-T1 is 0°C or higher, the ink has excellent drying properties after being ejected onto a substrate. When T2-T1 is 90°C or lower, bleeding of the ink after ejection is suppressed, resulting in good image quality. 0(℃)≦T2-T1≦90(℃)...Inequality (1)

[0011] <Discharge process> The ejection step is a step of ejecting ink onto a printing substrate by an ejection means. The ejection means is a nozzle having an ejection port on a nozzle surface for ejecting ink toward a printing substrate, and an example of the nozzle is an ejection head.

[0012] <First drying process> The first drying step is a step of drying the ink by heating the surface of the printing material onto which the ink has not been ejected, using a first drying means.

[0013] The heating temperature (T1) in the first drying step is preferably 20° C. or higher and 70° C. or lower. When the heating temperature (T1) is 20° C. or higher, the ink is excellent in drying properties after being ejected onto a printing substrate. When the heating temperature (T1) is 70° C. or lower, the ink is excellent in ejection stability. Furthermore, when the printing substrate is leather, the original texture can be maintained. The heating temperature (T1) refers to the temperature of the first drying means.

[0014] The heating time of the first drying means is not particularly limited and can be appropriately selected depending on the purpose, and can be adjusted depending on the ejection amount of ink and the performance of the printing device.

[0015] The first drying means is not particularly limited as long as it can heat the surface of the printed material on which the ink is not ejected, and can be appropriately selected depending on the purpose. For example, a hot air heater, an infrared heater, etc. can be mentioned.

[0016] The first drying step is not particularly limited as long as it is performed before the second drying step described below, and can be appropriately selected depending on the purpose. It can be performed simultaneously with the ejection means or after the ejection means.

[0017] <Second drying process> The second drying means is a means for heating the surface of the printing material onto which the ink has been ejected, to dry the ink. The second drying means is not particularly limited as long as it can heat the surface of the printed material onto which the ink has been ejected, and can be appropriately selected depending on the purpose. Examples of the second drying means include a hot air heater and an infrared heater.

[0018] The heating temperature (T2) in the second drying step is not particularly limited as long as it satisfies the inequality (1) and can be appropriately selected depending on the purpose, but is preferably 35° C. or higher and 90° C. or lower. The heating temperature (T2) refers to the temperature of the second drying means.

[0019] The heating time of the second drying means is preferably 1 minute or more and 15 minutes or less. When the heating time is 1 minute or more, the drying property is excellent. When the heating time is 15 minutes or less, in the case where the printed material is leather, the original texture can be maintained.

[0020] <Ink> The ink in the present invention contains organic solvent A having a boiling point of less than 250° C., organic solvent B having a boiling point of 250° C. or higher, and a resin, and preferably contains a coloring material, and further contains other components as necessary.

[0021] The viscosity of the ink at 25°C is 8.0 mPa·s or more and 11.0 mPa·s or less. When the viscosity is 8.0 mPa·s or more, the permeability of the ink after it lands on the printed substrate is suppressed, and the color development on the permeable printed substrate is improved. When the viscosity is 11.0 mPa·s or less, the ejection stability is improved. The viscosity of the ink at 25°C may be 9.0 mPa·s or more and 11.0 mPa·s or less.

[0022] The viscosity of the ink at 36°C is 5.5 mPa·s or more and 11.0 mPa·s or less. When the viscosity is 5.5 mPa·s or more and 11.0 mPa·s or less, even if the environmental temperature changes, the change in the viscosity of the ink can be suppressed, and the ejection stability is improved. The viscosity of the ink at 36°C may be 6.5 mPa·s or more and 11.0 mPa·s or less.

[0023] The method for measuring the viscosity is not particularly limited and may be appropriately selected depending on the purpose. For example, the viscosity may be measured using a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). The viscosity can be measured under the following conditions: 25° C., standard cone rotor (1°34′×R24), sample liquid amount of 1.2 mL, rotation speed of 50 rpm, and 3 minutes.

[0024] The surface tension of the ink at 25° C. is preferably 35 mN / m or less, and more preferably 32 mN / m or less, from the viewpoints of favorable leveling of the ink on the substrate and shortening the drying time of the ink.

[0025] The pH of the ink is preferably 7 or more and 12 or less, and more preferably 8 or more and 11 or less, from the viewpoint of preventing corrosion of metal members that come into contact with the ink.

[0026] -Organic solvent A- The organic solvent A is not particularly limited as long as it has a boiling point of less than 250° C. and can be appropriately selected depending on the purpose, and for example, a water-soluble organic solvent can be used. The boiling point refers to the initial boiling point at a standard pressure of 101.3 kPa. Examples of the water-soluble organic solvent include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers, and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, and ethylene carbonate.

[0027] The polyhydric alcohols are not particularly limited and can be appropriately selected depending on the purpose. Examples of the polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, and 2,3-butanediol. Examples of the hexanediol include pentanediol, 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, and petriol. Among these, 3-methyl-1,3-butanediol, 1,5-pentanediol, and 2,3-butanediol are preferred from the viewpoint of ejection stability.

[0028] The polyhydric alcohol alkyl ethers are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether.

[0029] The polyhydric alcohol aryl ethers are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0030] The nitrogen-containing heterocyclic compound is not particularly limited and can be appropriately selected depending on the purpose. Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone.

[0031] The amides are not particularly limited and can be appropriately selected depending on the purpose. Examples of the amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide.

[0032] The amines are not particularly limited and can be appropriately selected depending on the purpose. Examples of the amines include monoethanolamine, diethanolamine, and triethylamine.

[0033] The sulfur-containing compound is not particularly limited and can be appropriately selected depending on the purpose. Examples of the sulfur-containing compound include dimethyl sulfoxide, sulfolane, and thiodiethanol.

[0034] The content of the organic solvent A is 30% by mass or less, and preferably 25% by mass or less, relative to the ink. When the content is 30% by mass or less, the drying property of the ink is improved.

[0035] -Organic solvent B- The organic solvent B is not particularly limited as long as it has a boiling point of 250° C. or more, and can be appropriately selected depending on the purpose, and examples thereof include glycerin (boiling point: 290° C.), pentaerythriol (boiling point: 276° C.), triethylene glycol (boiling point: 285° C.), triethylene glycol monobutyl ether (boiling point: 278° C.), tripropylene glycol (boiling point: 273° C.), etc. The boiling point refers to the initial boiling point at a standard pressure of 101.3 kPa. By including organic solvent B having a boiling point of 250° C. or higher in the ink, the ink is less likely to solidify in the vicinity of the nozzle surface, and therefore the ink has excellent ejection stability.

[0036] The content of the organic solvent B is 1% by mass or more and 3% by mass or less, and preferably 1.5% by mass or more and 2.5% by mass or less, based on the ink. When the content is 1% by mass or more, the ink is less likely to adhere to the vicinity of the nozzle surface, and thus the ink ejection stability is excellent. When the content is 3% by mass or less, the ink is excellent in drying properties after being ejected onto a substrate.

[0037] -resin- The resin is preferably in the form of aqueous resin particles from the viewpoints of ease of preparation of the ink and dispersibility. The resin particles are not particularly limited and can be appropriately selected according to the purpose, and examples thereof include urethane resin particles, polyester resin particles, acrylic resin particles, vinyl acetate resin particles, styrene resin particles, butadiene resin particles, styrene-butadiene resin particles, vinyl chloride resin particles, acrylic styrene resin particles, and acrylic silicone resin particles. These may be used alone or in combination of two or more. Among these, urethane resin particles are preferred from the viewpoint of improving the scratch resistance of printed matter.

[0038] The urethane resin particles are urethane resins constituting the urethane resin particles, and are not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include polycarbonate-based urethane resins, polyester-based urethane resins, polyether-based urethane resins, etc. Among these, polycarbonate-based urethane resins and polyester-based urethane resins are preferred. The polycarbonate-based urethane resins and polyester-based urethane resins preferably have a structure derived from an alicyclic diisocyanate in terms of excellent abrasion resistance of printed matter. The polycarbonate-based urethane resin has excellent water resistance and abrasion resistance due to the high cohesive force of the carbonate group, and therefore it is possible to obtain an ink suitable for printing on materials used in harsh environments such as outdoor use. The polyester-based urethane resin can easily introduce a rigid structure having an aromatic ring or the like into the polyol portion, and has high hardness, a high glass transition temperature, and excellent heat resistance and abrasion resistance, making it possible to obtain an ink that is suitable for printed items used in environments where the material is likely to be subjected to loads such as friction.

[0039] As the resin particles, appropriately synthesized ones or commercially available ones may be used. Commercially available products of the resin particles include, for example, trade names: U-coat UX-485 (polycarbonate urethane resin particles), trade name: U-coat UWS-145 (polyester-based urethane resin particles), trade name: Permarine UA-368T (polycarbonate urethane resin particles), trade name: Permarine UA-200 (polyether-based urethane resin particles) (all manufactured by Sanyo Chemical Industries, Ltd.), trade names: Takelac W6110 (polycarbonate urethane resin particles), Takelac WS4000 (polycarbonate urethane resin particles), Takelac W6061 (polycarbonate urethane resin particles) ( Examples of such resins include those manufactured by Mitsui Chemicals, Inc.), trade name: Boncoat 5454 (styrene-acrylic resin particles, manufactured by DIC Corporation), trade name: SAE-1014 (styrene-acrylic resin particles, manufactured by Zeon Corporation), trade name: Cybinol SK-200 (acrylic resin particles, manufactured by Saiden Chemical Industries, Ltd.), trade name: Primal AC-22, trade name: AC-61 (acrylic resin particles, the above, manufactured by Rohm and Haas Co., Ltd.), trade name: Boncoat 4001 (acrylic resin particles, manufactured by DIC Corporation), and trade name: NANOCRYL (acrylic resin particles, manufactured by Toyochem Co., Ltd.). These may be used alone or in combination of two or more kinds. The resin particles may be of a forced emulsification type that utilizes a dispersant to be dispersed in an aqueous medium, but self-emulsification type resin particles having anionic groups in their molecular structure are preferred in order to prevent the dispersant from remaining in the coating film and reducing its strength.

[0040] The acid value of the anionic group of the self-emulsifying resin particles is preferably from 5 mgKOH / g to 100 mgKOH / g, more preferably from 5 mgKOH / mg to 50 mgKOH / mg, from the viewpoints of water dispersibility, abrasion resistance and chemical resistance.

[0041] The anionic group is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include a carboxyl group, a carboxylate group, a sulfonic acid group, a sulfonate group, etc. Among these, a carboxylate group and a sulfonate group, which are partially or completely neutralized with a basic compound or the like, are preferred from the viewpoint of maintaining good aqueous dispersion stability. As a method for producing the water dispersion of the resin particles having an anionic group, a method of adding a basic compound that can be used for neutralizing the anionic group to the water dispersion can be mentioned.

[0042] Examples of the basic compound include organic amines such as ammonia, triethylamine, pyridine, and morpholine, alkanolamines such as monoethanolamine, and metal base compounds including Na, K, Li, and Ca, etc. These may be used alone or in combination of two or more.

[0043] As a method for producing an aqueous dispersion using the forced emulsification type resin particles, for example, a surfactant such as a nonionic surfactant or an anionic surfactant can be used. These can be used alone or in combination of two or more. Among these, nonionic surfactants are preferred from the viewpoint of water resistance.

[0044] Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene derivative, polyoxyethylene fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester, polyoxyethylene propylene polyol, sorbitan fatty acid ester, polyoxyethylene hydrogenated castor oil, polyoxyalkylene polycyclic phenyl ether, polyoxyethylene alkylamine, alkyl alkanolamide, polyalkylene glycol (meth)acrylate, etc. These may be used alone or in combination of two or more. Among these, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine are preferred.

[0045] Examples of the anionic surfactant include alkyl sulfate, polyoxyethylene alkyl ether sulfate, alkylbenzene sulfonate, α-olefin sulfonate, methyl taurate, sulfosuccinate, ether sulfonate, ether carboxylate, fatty acid salt, naphthalene sulfonate-formaldehyde condensate, alkylamine salt, quaternary ammonium salt, alkyl betaine, and alkylamine oxide. These may be used alone or in combination of two or more. Among these, polyoxyethylene alkyl ether sulfate and sulfosuccinate are preferred.

[0046] The content of the surfactant is preferably 0.1% by mass to 30% by mass, more preferably 5% by mass to 20% by mass, based on the resin. When the content is 0.1% by mass to 30% by mass, the resin forms a film favorably, an ink having excellent adhesion and water resistance is obtained, and blocking of the printed matter can be prevented.

[0047] The volume average particle size of the resin particles is not particularly limited and can be appropriately selected depending on the purpose. However, in terms of being able to form a tough continuous resin coating by increasing the number of contact sites between the organic solvent and the surfaces of the resin particles, the volume average particle size is preferably 10 nm or more and 1,000 nm or less, more preferably 10 nm or more and 200 nm or less, and particularly preferably 10 nm or more and 100 nm or less. The volume average particle size can be measured, for example, by using a particle size analyzer (Microtrac Model UPA9340, manufactured by Nikkiso Co., Ltd.).

[0048] The content of the resin is 5% by mass or more and 15% by mass or less, and preferably 8% by mass or more and 13% by mass or less, based on the ink. When the content is 5% by mass or more, the ink has a high viscosity, and has high color development and abrasion resistance even when applied to a permeable printing substrate. When the content is 15% by mass or less, the ink is less likely to adhere to the nozzle surface of the ejection head, and therefore the ink has excellent ejection stability.

[0049] The glass transition temperature (Tg) of the resin particles is preferably equal to or lower than 0° C. When the ink contains one or more types of resin particles having a glass transition temperature of equal to or lower than 0° C., the ink has improved film-forming properties on a printed material and excellent abrasion resistance. The glass transition temperature of the resin particles can be measured by, for example, differential scanning calorimetry (DSC), differential thermal analysis (DTA), or the like.

[0050] The content of the resin particles is preferably 30% by mass or more and 70% by mass or less, more preferably 40% by mass or more and 60% by mass or less, based on the resin. When the content is 30% by mass or more, the ink film-forming property on the printed matter is improved and the strength of the ink film is increased, so that the printed matter has excellent abrasion resistance. When the content is 70% by mass or less, the ink film on the nozzle surface of the ejection head is suppressed, so that the ejection reliability is excellent.

[0051] -Coloring materials- The coloring material is not particularly limited and can be appropriately selected depending on the purpose. Examples of the coloring material include pigments and dyes.

[0052] The pigment may be an inorganic pigment or an organic pigment. These may be used alone or in combination of two or more. Mixed crystals may also be used.

[0053] Examples of the pigment that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver pigments, and metallic pigments.

[0054] Examples of the inorganic pigment that can be used include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as carbon black produced by a known method such as a contact method, a furnace method, or a thermal method.

[0055] Examples of the organic pigment that can be used include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.

[0056] Specific examples of the pigment include, for black colors, carbon blacks such as furnace black, lamp black, acetylene black, and channel black (CI Pigment Black 7); metals such as copper, iron (CI Pigment Black 11), and titanium oxide; and organic pigments such as aniline black (CI Pigment Black 1). In addition, for color, CI Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, CI Pigment Yellow Range 5, 13, 16, 17, 36, 43, 51, CI Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88 , 101 (red oxide), 104, 105, 106, 108 (cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, CI Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38; CI Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3, 15:4 (Phthalocyanine Blue), 16, 17:1, 56, 60, 63; CI Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.

[0057] The dye is not particularly limited and can be appropriately selected depending on the purpose. Acid dyes, direct dyes, reactive dyes, basic dyes, etc. can be used. These may be used alone or in combination of two or more.

[0058] Examples of the dyes include CI Acid Yellow 17, 23, 42, 44, 79, 142, CI Acid Red 52, 80, 82, 249, 254, 289, CI Acid Blue 9, 45, 249, CI Acid Black 1, 2, 24, 94, CI Food Black 1, 2, CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, CI Direct Red 1, 4, 9, 80, 81, 225, 227, CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, CI Directed Black 19, 38, 51, 71, 154, 168, 171, 195, and CI Reactive Red. 14, 32, 55, 79, 249, and CI Reactive Black 3, 4, and 35.

[0059] The content of the coloring material in the ink is preferably from 0.1% by mass to 15% by mass, and more preferably from 1% by mass to 10% by mass, from the viewpoints of improving image density, good fixability, and ejection stability.

[0060] Methods for dispersing the pigment to obtain an ink include a method of introducing a hydrophilic functional group into the pigment to make it a self-dispersing pigment, a method of dispersing the pigment by coating the surface of the pigment with a resin, and a method of dispersing the pigment using a dispersant. As a method for introducing a hydrophilic functional group into a pigment to make it a self-dispersing pigment, for example, a method in which a functional group such as a sulfone group or a carboxyl group is added to a pigment (e.g., carbon) to make it dispersible in water can be mentioned.

[0061] As a method for dispersing the pigment by coating the surface with a resin, a method for encapsulating the pigment in a microcapsule to make it dispersible in water can be mentioned. This can be called a resin-coated pigment. In this case, it is not necessary for all the pigments blended in the ink to be coated with a resin, and uncoated or partially coated pigments may be dispersed in the ink as long as the effect of the present invention is not impaired. Resin-coated pigments are preferred from the viewpoint of storage stability and ejection reliability of the ink.

[0062] Examples of the method for dispersing using the dispersant include a method for dispersing using a known low molecular weight dispersant or a known high molecular weight dispersant, typified by a surfactant. The dispersant is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, sodium naphthalenesulfonate formalin condensates, etc. The dispersant may be used alone or in combination of two or more kinds. The nonionic surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, RT-100 manufactured by Takemoto Oil Co., Ltd. can be used.

[0063] A pigment dispersion can be obtained by mixing the pigment with materials such as water and an organic solvent. Also, an ink can be produced by mixing a pigment, water, a dispersant, and the like to obtain a pigment dispersion and then mixing the pigment, water, an organic solvent, and the like. The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as required, and adjusting the particle size.

[0064] The number-average particle diameter of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the purpose. From the viewpoints of excellent dispersion stability and ejection stability and high image quality such as image density, the number-average particle diameter is preferably 20 nm or more and 500 nm or less, and more preferably 20 nm or more and 150 nm or less.

[0065] The particle size of the pigment can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.). The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of good ejection stability and excellent image density, the content is preferably from 0.1% by mass to 50% by mass, and more preferably from 0.1% by mass to 30% by mass. It is preferable that the pigment dispersion is degassed, if necessary, by filtering coarse particles using a filter, a centrifugal separator, or the like.

[0066] -Other ingredients- The other components are not particularly limited and may be appropriately selected depending on the purpose. Examples of the other components include silicone surfactants and additives.

[0067] --Silicone surfactants-- The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the silicone-based surfactant include silicone-based surfactants having modified groups such as side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and both-end side-chain modified polydimethylsiloxane.

[0068] Examples of the silicone surfactant include polyether-modified silicone surfactants having a modified group such as a polyoxyethylene group or a polyoxyethylene polyoxypropylene group.

[0069] The polyether-modified silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, polyoxyalkylene-modified dimethylpolysiloxane represented by the following chemical formula 1 can be mentioned. [ka] (chemical formula 1) (In Chemical Formula 1, m represents an integer of 0 to 10, n represents an integer of 1 to 5, a represents an integer of 0 to 20, b represents an integer of 0 to 20, R represents any one of an alkyl group and an alkylene group having 1 to 10 carbon atoms, and R' represents any one of a hydrogen atom, an alkyl group and an alkylene group having 1 to 10 carbon atoms.)

[0070] The polyoxyalkylene-modified dimethylpolysiloxane has a polyalkylene oxide structure on the Si portion side chain of the dimethylpolysiloxane.

[0071] As the silicone surfactant having a modifying group, a suitably synthesized one or a commercially available product may be used. Examples of the commercially available products include surfactants manufactured by Shin-Etsu Chemical Co., Ltd., such as SAG503A, SAG002, SAG005, KF-618, KF-642, and KF-643; surfactants manufactured by Nippon Emulsion Co., Ltd., such as EMALEX-SS-5602 and SS-1906EX; surfactants manufactured by Toray Dow Corning Silicone Co., Ltd., such as FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, and FZ-2164; surfactants manufactured by BYK-Chemie Co., Ltd., such as BYK-33 and BYK-387; surfactants manufactured by Toshiba Silicone Co., Ltd., such as TSF4440, TSF4452, and TSF4453; and surfactants manufactured by Evonic Co., Ltd., such as TEGO Twin4000.

[0072] The HLB value of the silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of color development, it is preferably from 8.0 to 11.5, more preferably from 9.0 to 11.5. The HLB value can be calculated by the Griffin method.

[0073] The content of the silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of color development and ejection stability, however, the content is preferably from 0.5% by mass to 1.5% by mass, and more preferably from 0.7% by mass to 1.3% by mass, based on the total amount of the ink.

[0074] --Additives-- The additives are not particularly limited and can be appropriately selected depending on the purpose. Examples of the additives include water, surfactants, antifoaming agents, antiseptic and antifungal agents, rust inhibitors, and pH adjusters.

[0075] The water content is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of the drying property and ejection reliability of the ink, the water content is preferably from 10% by mass to 90% by mass, and more preferably from 20% by mass to 60% by mass.

[0076] The defoaming agent is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include silicone-based defoaming agents, polyether-based defoaming agents, and fatty acid ester-based defoaming agents. These may be used alone or in combination of two or more. Among these, silicone-based defoaming agents are preferred because of their excellent foam breaking effect.

[0077] The antiseptic and antifungal agent is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include 1,2-benzisothiazolin-3-one.

[0078] The rust inhibitor is not particularly limited and can be appropriately selected depending on the purpose. Examples of the rust inhibitor include acid sulfite and sodium thiosulfate.

[0079] The pH adjuster is not particularly limited as long as it is capable of adjusting the pH to 7 or more, and can be appropriately selected depending on the purpose. Examples of the pH adjuster include amines such as diethanolamine and triethanolamine.

[0080] (Printing device) The printing device of the present invention comprises: ink containing means for containing ink which contains 30 mass % or less of organic solvent A having a boiling point of less than 250°C, 1 mass % to 3 mass % of organic solvent B having a boiling point of 250°C or more, and 5 mass % to 15 mass % of resin, the ink having a viscosity of 8.0 mPa·s to 11.0 mPa·s at 25°C and a viscosity of 5.5 mPa·s to 11.0 mPa·s at 36°C, and which takes 10.0 seconds or less at 25°C for a droplet of the ink with a volume of 2.5 μL ejected onto a substrate to reduce in volume to 0.1 μL or less; a discharge means including a nozzle having a discharge port on a nozzle surface for discharging the ink toward the printing material; a first drying means for heating a surface of the printing material on which the ink is not ejected, to dry the ink; and a second drying means for heating the surface of the printed material onto which the ink has been ejected to dry the ink, and further comprising other means, as necessary, such as an ink containing means, a stimulus generating means, and a wiping means.

[0081] <Discharge means> The ejection means is a nozzle having an ejection port on a nozzle surface for ejecting ink toward a printing substrate, and an example of the nozzle is an ejection head. The ejection head preferably has a nozzle substrate and an ink-repellent film on the surface of the nozzle substrate, and the surface of the nozzle substrate on which the ink-repellent film is provided is the nozzle surface.

[0082] The nozzle substrate is provided with nozzle holes, and the number, shape, size, material, structure, etc. of the nozzle holes are not particularly limited and can be appropriately selected depending on the purpose. The nozzle substrate has an ink ejection side surface from which ink is ejected from the nozzle holes, and a liquid chamber joining surface located on the opposite side to the ink ejection side surface. The planar shape of the nozzle substrate is not particularly limited and can be appropriately selected depending on the purpose, and examples of the planar shape include a rectangle, a square, a rhombus, a circle, an ellipse, etc. In addition, examples of the cross-sectional shape of the nozzle substrate include a flat plate shape, a plate shape, etc. The size of the nozzle substrate is not particularly limited and can be appropriately selected depending on the size of the nozzle plate.

[0083] The material of the nozzle substrate is not particularly limited and can be appropriately selected depending on the purpose. For example, stainless steel, Al, Bi, Cr, InSn, ITO, Nb, Nb 2 O 5 , NiCr, Si, SiO 2 , Sn, Ta 2 O 5 , Ti, W, ZnO(ZnO+Al 2 O 3), Zn, etc. These may be used alone or in combination of two or more. Among these, stainless steel is preferred from the viewpoint of rust prevention. The stainless steel is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, precipitation hardening stainless steel, etc. These may be used alone or in combination of two or more.

[0084] At least the surface of the nozzle substrate on the ink ejection side may be subjected to oxygen plasma treatment to introduce hydroxyl groups in order to improve adhesion between the ink repellent film and the nozzle substrate.

[0085] The nozzle holes are not particularly limited in number, arrangement, interval, opening shape, opening size, cross-sectional shape of the opening, etc., and may be appropriately selected depending on the purpose. The arrangement of the nozzle holes is not particularly limited and can be appropriately selected depending on the purpose. For example, a plurality of the nozzle holes may be arranged at equal intervals along the longitudinal direction of the nozzle substrate.

[0086] The arrangement of the nozzle holes can be appropriately selected depending on the type of ink to be ejected, but one to multiple rows are preferable, and one to four rows are more preferable. The number of the nozzle holes per row is not particularly limited and can be appropriately selected depending on the purpose, but is preferably from 10 to 10,000, and more preferably from 50 to 500. The interval (pitch) P, which is the shortest distance between the centers of adjacent nozzle holes, is not particularly limited and can be appropriately selected depending on the purpose, but is preferably, for example, from 21 μm to 169 μm. The opening shape of the nozzle hole is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a circle, an ellipse, a rectangle, etc. Among these, a circle is preferable from the viewpoint of ejecting ink droplets.

[0087] The ink-repellent film is formed on the surface of the nozzle substrate on the ink ejection side. The ink-repellent film is not particularly limited as long as it can repel the ink, and can be appropriately selected depending on the purpose, but it is preferable that the ink-repellent film contains a fluorine-containing acrylate ester polymer or a polymer having a fluorine-containing heterocyclic structure in the main chain. By containing the fluorine-containing acrylate ester polymer or the polymer having a fluorine-containing heterocyclic structure in the main chain, the surface free energy becomes very small, and it is preferable that the ink used in the present invention can maintain a state where it is difficult to wet even with the ink having a low surface tension.

[0088] <First drying means> The first drying means is a means for heating a surface of the printing material onto which the ink is not ejected, to dry the ink. The first drying means is not particularly limited as long as it can heat the surface of the printed material on which the ink is not ejected, and can be appropriately selected depending on the purpose. For example, a hot air heater, an infrared heater, etc. can be mentioned. The heating temperature (T1) by the first drying means is preferably 20° C. or higher and 70° C. or lower. When the heating temperature (T1) is 20° C. or higher, the ink is excellent in drying properties after being ejected onto a printing substrate. When the heating temperature (T1) is 70° C. or lower, the ink is excellent in ejection stability. Furthermore, when the printing substrate is leather, the original texture can be maintained. The heating temperature (T1) refers to the temperature of the first drying means.

[0089] <Second drying means> The second drying means is a means for heating the surface of the printing material onto which the ink has been ejected, to dry the ink. The second drying means is not particularly limited as long as it can heat the surface of the printed material onto which the ink has been ejected, and can be appropriately selected depending on the purpose. Examples of the second drying means include a hot air heater and an infrared heater. The heating temperature (T2) by the second drying means is not particularly limited as long as it satisfies the inequality (1) and can be appropriately selected depending on the purpose, but is preferably 35° C. or higher and 90° C. or lower. The heating temperature (T2) refers to the temperature of the second drying means.

[0090] <Ink storage means> The ink containing means is not particularly limited as long as it is a member capable of containing the ink, and can be appropriately selected depending on the purpose. Examples of the ink containing means include an ink filled container and an ink tank. The ink-filled container is a container filled with the ink, and further includes other members appropriately selected as necessary. The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected depending on the purpose. For example, it may have at least an ink bag formed of an aluminum laminate film, a resin film, etc. The ink tank includes a main tank and a sub-tank.

[0091] <Means of generating stimuli> The stimulus generating means is a means for generating a stimulus to be applied to the ink. The stimulus in the stimulus generating means is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include heat (temperature), pressure, vibration, light, etc. These may be used alone or in combination of two or more. Among these, heat and pressure are preferred. Examples of the stimulus generating means include a heating device, a pressure device, a piezoelectric actuator such as a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a light, a thermal actuator that utilizes a phase change caused by film boiling of ink using an electrothermal conversion element such as a heating resistor, a shape memory alloy actuator that uses a metal phase change caused by a temperature change, and an electrostatic actuator that uses electrostatic force.

[0092] When the stimulus is "heat", thermal energy corresponding to a recording signal is applied to the ink in the ink ejection head using a thermal head, etc. The thermal energy generates bubbles in the ink, and the ink can be ejected as droplets from the nozzle holes of the nozzle plate by the pressure of the bubbles.

[0093] When the stimulus is "pressure," for example, the piezoelectric element is flexed by applying a voltage to the piezoelectric element attached to a position called the pressure chamber in the ink flow path in the ink ejection head. This causes the volume of the pressure chamber to contract, allowing the ink to be ejected as droplets from the nozzle hole of the ink ejection head. Among these, the piezoelectric method in which a voltage is applied to a piezoelectric element to cause ink to fly is preferred.

[0094] <Wiping method> In the printing method of the present invention, in the event that dirt adheres to the nozzle surface due to ink droplets adhering to the nozzle surface as ink is ejected, a wiping means can be provided that can wipe off the dirt adhering to the nozzle surface by using the wiping means. The wiping member of the wiping means is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a wiper blade, a nonwoven fabric, etc. When a nonwoven fabric is used as the wiping member, wiping efficiency can be improved by applying a cleaning liquid to the wiping member during wiping.

[0095] An example of a printing apparatus and a printing method of the present invention will be described with reference to FIGS.

[0096] Fig. 1 is a perspective view showing a typical example of a printing device of the present invention, and the printing device shown in Fig. 1 is a serial type printing device. Fig. 2 is a perspective view showing a typical main tank in the printing device of the present invention.

[0097] The printing device is a serial type image forming device. A mechanism section 420 is provided inside an exterior 401 of the image forming device 400. Each ink storage section 411 of the main tanks 410 (410k, 410c, 410m, and 410y, respectively) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is formed of a packaging material such as an aluminum laminate film.

[0098] The ink containing section 411 is housed in, for example, a plastic container case 414. As a result, the main tank 410 is used as an ink cartridge for each color. On the other hand, a cartridge holder 404 is provided at the back side of the opening when the cover 401c of the apparatus body is opened. A main tank 410 is detachably attached to the cartridge holder 404. As a result, each ink outlet 413 of the main tank 410 communicates with an ejection head 434 for each color via a supply tube 436 for each color, and ink can be ejected from the ejection head 434 to a recording medium.

[0099] FIG. 3 is a schematic diagram showing the configuration of the printing device 1. As shown in FIG. The printing device 1 is a serial printing device. As shown in Fig. 3, the printing device 1 includes an image forming unit 2 that prints a required image, a drying device 3, a roll media storage unit 4, and a transport mechanism 5. The roll media storage section 4 stores roll media (recording media) 40. The roll media storage section 4 can store recording media 40 of different sizes in the width direction. The recording medium 40 is not particularly limited and can be appropriately selected depending on the purpose. Examples of the recording medium 40 include non-permeable media such as PVC (polyvinyl chloride) and PET (polyethylene terephthalate) films, permeable media such as cloth and synthetic paper, and wallpaper media made of polyester material.

[0100] The transport mechanism 5 constitutes a roll-to-roll type transport means and includes a pair of nip rollers 51, a pair of driven rollers 52, and a take-up roller 53 on a transport path 54 for the recording medium 40. The nip roller 51 is provided on the front side (upstream side in the transport direction A) of the image forming unit 2. The nip roller 51 transports the sandwiched recording medium 40 toward the image forming unit 2 by rotating in conjunction with the drive of a motor. The winding roller 53 rotates as the motor M is driven, thereby winding up the recording medium 40 after printing. The driven roller 52 rotates in response to the transport of the recording medium 40 .

[0101] The transport mechanism 5 is equipped with a wheel encoder for detecting the transport speed. The conveying speed of the conveying mechanism 5 is controlled by controlling the motor based on a target value and a speed detection value obtained by sampling detection pulses from a wheel encoder 55 .

[0102] The recording medium 40 stored in the roll medium storage section 4 is transported to the image forming section 2 by the rotation of the nip roller 51 via a driven roller 52 . When the recording medium 40 reaches the image forming unit 2 , a required image is printed by the image forming unit 2 , and the recording medium 40 after printing is taken up by the rotation of a take-up roller 53 .

[0103] The image forming unit 2 includes a carriage 21 . The carriage 21 is slidably supported by a guide rod (guide rail) 22 . The carriage 21 moves on a guide rod (guide rail) 22 in a direction (main scanning direction) perpendicular to the transport direction A of the recording medium 40 as the motor M is driven. Specifically, the carriage 21 moves back and forth within a recording area where the image forming unit 2 can print on the recording medium 40 transported by the transport mechanism 5, within a main scanning area which is a movable area in the main scanning direction.

[0104] The carriage 21 is equipped with a recording head 20 having an array of nozzle holes, which are ejection ports for ejecting droplets. The recording head 20 is integrally provided with a tank that supplies ink to the recording head 20. However, the recording head 20 is not limited to one that is integrally provided with a tank, and may be one that is provided with a tank separately. The recording head 20 functions as a liquid ejection unit and ejects ink droplets of each of the process color recording liquids, namely black (K), yellow (Y), magenta (M), and cyan (C). Black (K), yellow (Y), magenta (M), and cyan (C) are inks for forming images.

[0105] The image forming unit 2 includes a platen 23 that supports a recording medium 40 below the recording head 20 when the recording head 20 prints.

[0106] The image forming unit 2 includes an encoder sheet for detecting the main scanning position of the carriage 21 along the main scanning direction of the carriage 21. The carriage 21 also includes an encoder. The image forming unit 2 detects the main scanning position of the carriage 21 by reading an encoder sheet with an encoder of the carriage 21 .

[0107] The carriage 21 is equipped with a sensor 24 that optically detects the edge of the recording medium 40 in accordance with the movement of the carriage 21. A detection signal from this sensor 24 is used to calculate the position of the edge of the recording medium 40 in the main scanning direction and the width of the recording medium 40.

[0108] The drying device 3 includes a preheater 30, a platen heater 31 which is a first drying means used in a first drying step, a drying heater 32 which is a second drying means used in a second drying step, and a hot air fan 33. Here, either the drying heater 32 or the hot air fan 33 may be used alone or both may be used in combination. The preheater 30, the platen heater 31, and the drying heater 32 are, for example, electric heaters using ceramics or nichrome wire.

[0109] The preheater 30 is provided upstream of the image forming unit 2 in the transport direction A of the recording medium 40. The preheater 30 preliminarily heats the recording medium 40 being transported by the transport mechanism 5.

[0110] The platen heater 31 is disposed on the platen 23. The platen heater 31 heats the recording medium 40 on which the ink droplets ejected from the nozzle holes of the recording head 20 land.

[0111] The drying heater 32 is provided downstream of the image forming unit 2 in the transport direction A of the recording medium 40. The drying heater 32 continues to heat the recording medium 40 printed by the image forming unit 2, and promotes drying of the landed ink droplets.

[0112] The hot air fan 33 is provided downstream of the drying heater 32 (image forming unit 2) in the transport direction A of the recording medium 40. The hot air fan 33 blows hot air onto the recording surface (the surface onto which the ink is ejected) of the recording medium 40 onto which the ink has landed. The hot air fan 33 blows hot air directly onto the ink on the recording surface of the recording medium 40, thereby lowering the humidity of the atmosphere around the recording surface of the recording medium 40 and completely drying it.

[0113] By incorporating the drying device 3, the printing device 1 can use, as the recording medium 40, non-permeable media that does not allow ink to soak in, such as polyvinyl chloride film, polyethylene terephthalate (PET) film, and acrylic film.

[0114] In the printing device 1 in which the carriage 21 moves back and forth across the width of the recording medium 40 while ejecting ink from the recording head 20 to form an image, there are two types of printing: unidirectional printing, in which ink is ejected only when the carriage moves forward to form an image, and bidirectional printing, in which ink is ejected both forward and backward to form an image. The printing device 1 primarily uses bidirectional printing, which is advantageous in terms of printing speed. In this case, the operation of ejecting ink from the recording head 20 while the carriage 21 moves in the main scanning direction is considered to be one scan.

[0115] For the control configuration of the printing device 1, the description in JP 2017-105193 A can be referenced, for example.

[0116] <Print material> The printing substrate is not particularly limited and can be appropriately selected depending on the purpose. Examples of the printing substrate include paper substrates such as ordinary paper, glossy paper, and special paper, clothing cloth such as T-shirts, and fabrics such as fabrics. The printing method of the present invention provides high color development even on permeable substrates, and is also excellent in ejection stability, drying properties, and abrasion resistance.

[0117] In the present invention, examples of the cloth substrate include fabrics and cloths made of fibers such as knitted fabrics, woven fabrics, and nonwoven fabrics. The material used for the cloth-like printing substrate may include cellulose fibers derived from pulp, cotton, hemp, etc., synthetic fibers made from polyolefin resins, polyamide resins, polyacrylic resins, vinylon resins, vinylidene resins, polyvinyl alcohol, polyvinyl chloride, polyester resins, benzoate resins, polychlar, and phenolic resins, etc., natural fibers such as silk and wool, regenerated fibers including rayon fiber, cupra fiber, and lyocell fiber, semi-synthetic fibers such as acetate fiber, triacetate fiber, and promix fiber, metal fibers, glass fibers, and inorganic fibers such as rock fibers. These fibers may be used alone or in combination. The cloth-like printing material may be made of a fiber obtained by blending the cellulose fiber or natural fiber with the synthetic fiber.

[0118] The permeability of the printing substrate can be defined from the change in the volume of the ink ejected onto the printing substrate. Specifically, a printing substrate is considered to be permeable if the time it takes for a droplet of the ink with a volume of 2.5 μL ejected onto the printing substrate to decrease to a volume of 0.1 μL or less at 25° C. is 10.0 seconds or less. The contact angle meter used to evaluate the permeability of the printed material is not particularly limited and can be appropriately selected depending on the purpose. For example, Dmo-5-1 (manufactured by Kyowa Interface Science Co., Ltd.) can be used for measurement. During measurement, 2.5 μl of the ink is pushed out from a syringe equipped with a syringe needle, and the ink is ejected onto the printed material by a droplet method to measure the change in volume. It is preferable to use a Teflon (registered trademark) syringe needle for improving the reproducibility of the measurement. The volume of the ink at a certain time after the ink is placed on the substrate can be calculated by the following formula. [ka] In the above formula, V(t) is the volume of the ink on the substrate at a certain time (unit: μl), R v (t) is the radius of the ink droplet on the substrate at a certain time (unit: mm), θ D (t) is the contact angle (in radians) of the ink droplet on the substrate at a certain time. v (t), and the θ D (t) can be evaluated using a contact angle meter. D For (t), the value obtained using the θ / 2 method shall be used. EXAMPLES

[0119] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, "parts" means "parts by mass" and "%" means "% by mass" except in the evaluation criteria.

[0120] <Production example of black pigment dispersion> In a flask, 11.2 g of styrene, 2.8 g of acrylic acid, 12 g of lauryl methacrylate, 4 g of polyethylene glycol methacrylate, 4 g of styrene macromer, and 0.4 g of mercaptoethanol were mixed and heated to 65°C. Next, a mixed solution of 100.8 g of styrene, 25.2 g of acrylic acid, 108 g of lauryl methacrylate, 36 g of polyethylene glycol methacrylate, 60 g of hydroxylethyl methacrylate, 36 g of styrene macromer, 3.6 g of mercaptoethanol, 2.4 g of azobismethylvaleronitrile, and 18 g of methyl ethyl ketone was dropped into the flask over 2.5 hours. Then, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. Next, after aging for 1 hour at 65°C, 0.8 g of azobismethylvaleronitrile was added, and the reaction was continued for another 1 hour. After the reaction was completed, 364 g of methyl ethyl ketone was added to the flask, and 800 g of polymer solution A with a solid content concentration of 50% was obtained. Next, 28 g of polymer solution A, 42 g of carbon black (Black Pearls 1000, manufactured by Cabot Corporation), 13.6 g of a 1 mol / L aqueous potassium hydroxide solution, 20 g of methyl ethyl ketone, and 13.6 g of water were thoroughly stirred and then kneaded with a roll mill to obtain a paste. The obtained paste was added to 200 g of pure water and thoroughly stirred, after which the methyl ethyl ketone was removed using an evaporator, and the mixture was pressure filtered through a polyvinylidene fluoride membrane filter having an average pore size of 5 μm. The water content was then adjusted so that the solids concentration was 20%, and a black pigment dispersion with a solids concentration of 20% was obtained.

[0121] <Production Example of Cyan Pigment Dispersion> A cyan pigment dispersion having a solid content of 20% was obtained in the same manner as in the preparation example of the black pigment dispersion, except that Pigment Blue 15:4 (SENSIENT SMART Cyan 3154BA) was used instead of carbon black in the preparation of the black pigment dispersion.

[0122] <Production Example of Magenta Pigment Dispersion> A magenta pigment dispersion having a solid content concentration of 20% was obtained in the same manner as in the preparation example of the black pigment dispersion, except that Pigment Red 122 (Pigment Red 122 manufactured by Sun Chemical Co.) was used instead of carbon black in the preparation of the black pigment dispersion.

[0123] <Production Example of Yellow Pigment Dispersion> A yellow pigment dispersion having a solid content of 20% was obtained in the same manner as in the preparation example of the black pigment dispersion, except that Pigment Yellow 74 (SMART Yellow 3074BA manufactured by ENSIENT) was used instead of carbon black in the preparation of the black pigment dispersion.

[0124] <Synthesis Example 1 of Polyester-based Urethane Resin Emulsion> In a nitrogen-substituted vessel equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 124.4 g of polyester polyol (trade name: Polylite OD-X-2251, manufactured by DIC Corporation, average molecular weight 2,000), 9.7 g of 2,2-dimethylolpropionic acid, 29.8 g of isophorone diisocyanate, 77.1 g of methyl ethyl ketone as an organic solvent, and 0.06 g of DMTDL (dibutyltin dilaurate) as a catalyst were used to react. After the reaction was continued for 4 hours, 30.7 g of methyl ethyl ketone was supplied as a dilution solvent, and the reaction was continued further. When the average molecular weight of the reactant reached a range of 20,000 to 60,000, 1.4 g of methanol was added to terminate the reaction, thereby obtaining an organic solvent solution of a urethane resin. 13.4 g of 48% by mass potassium hydroxide aqueous solution was added to the organic solvent solution of the urethane resin to neutralize the carboxyl group of the urethane resin, and then 715.3 g of water was added and thoroughly stirred, followed by aging and desolvation to obtain a polyester-based urethane resin emulsion 1 with a solid content concentration of 30% by mass. The glass transition temperature of the obtained polyester-based urethane resin emulsion 1 was measured to be 74° C. The volume average particle size was 69 nm.

[0125] <Synthesis Example 2 of Polyester-based Urethane Resin Emulsion> A 2 L reactor equipped with a stirrer, a thermometer, a nitrogen seal tube (nitrogen inlet tube), and a condenser was charged with 100 g of methyl ethyl ketone, 345 g of polyester polyol (1) (a polyester polyol (number average molecular weight = 2,000, average number of functional groups: 2) obtained from isophthalic acid / adipic acid = 6 / 4 (molar ratio) and ethylene glycol / neopentyl glycol = 1 / 9 (molar ratio)), and 9.92 g of 2,2-dimethylolpropionic acid (DMPA), and the mixture was mixed uniformly at 60°C. Thereafter, 45.1 g of triethylene glycol diisocyanate (TEGDI) and 0.08 g of dioctyltin dilaurate (DOTDL) were charged and reacted at 72°C for 3 hours to obtain a polyurethane solution. 80 g of isophthalic acid (IPA), 220 g of methyl ethyl ketone (MEK), 3.74 g of TEA (triethylamine), and 596 g of water were charged into the obtained polyurethane solution to invert the phase, and MEK and IPA were removed with a rotary evaporator to obtain a polyester-based urethane resin emulsion 2. The obtained aqueous emulsion was cooled to room temperature, and then ion-exchanged water and an aqueous sodium hydroxide solution were added to adjust the solid concentration to 30 mass% and pH to 8. The glass transition temperature of the obtained polyester-based urethane resin emulsion 2 was measured and found to be -5°C. The volume average particle size was also 88 nm.

[0126] <Synthesis Example 1 of Polyether-based Urethane Resin Emulsion> In a nitrogen-substituted vessel equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 100.2 g of polyether polyol (trade name: PTMG1000, manufactured by Mitsubishi Chemical Corporation, average molecular weight: 1,000), 15.7 g of 2,2-dimethylolpropionic acid, 48.0 g of isophorone diisocyanate, 77.1 g of methyl ethyl ketone as an organic solvent, and 0.06 g of DMTDL (dibutyltin dilaurate) as a catalyst were used to react. After the reaction was continued for 4 hours, 30.7 g of methyl ethyl ketone was supplied as a dilution solvent, and the reaction was continued further. When the average molecular weight of the reactant reached a range of 20,000 to 60,000, 1.4 g of methanol was added to terminate the reaction, thereby obtaining an organic solvent solution of a urethane resin. The carboxyl group of the urethane resin was neutralized by adding 13.4 g of 48% by mass potassium hydroxide aqueous solution to the organic solvent solution of the urethane resin, and then 715.3 g of water was added and thoroughly stirred, followed by aging and desolvation to obtain a polyether-based urethane resin emulsion with a solid content concentration of 30% by mass. The glass transition temperature of the obtained polyether-based urethane resin emulsion was measured to be 43°C. The volume average particle size was 121 nm.

[0127] <Synthesis Example 1 of Polycarbonate-based Urethane Resin Emulsion> In a reaction vessel equipped with a stirrer, reflux condenser and thermometer, 1,500g of polycarbonate diol (a reaction product of 1,6-hexanediol and dimethyl carbonate (number average molecular weight (Mn): 1,200)), 220g of 2,2-dimethylolpropionic acid (DMPA), and 1,347g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream and heated to 60°C to dissolve DMPA. Next, 1,223g (5.5 moles) of isophorone diisocyanate and 2.6g of dibutyltin dilaurate (catalyst) were added and heated to 90°C, and a urethane reaction was carried out over 5 hours to obtain an isocyanate-terminated urethane prepolymer. The reaction mixture was cooled to 80°C, and 149g of triethylamine was added and mixed, from which 4,340g was extracted and added to a mixed solution of 5,400g of water and 15g of triethylamine under strong stirring. Next, 1,500 g of ice was added, and 626 g of 35% 2-methyl-1,5-pentanediamine aqueous solution was added to carry out a chain extension reaction, and the solvent was distilled off so that the solid content concentration became 30 mass %, to obtain a polycarbonate urethane resin emulsion 1 having a structure derived from an alicyclic diisocyanate. The glass transition temperature of the obtained polycarbonate-based urethane resin emulsion 1 was measured and found to be 83° C. The volume average particle size was also found to be 71 nm.

[0128] <Synthesis Example 2 of Polycarbonate-based Urethane Resin Emulsion> In a reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 1,500 g of polycarbonate diol (a reaction product of 1,6-hexanediol and dimethyl carbonate (number average molecular weight (Mn): 1,200)), 220 g of 2,2-dimethylolpropionic acid (DMPA), and 1,347 g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream and heated to 60°C to dissolve DMPA. Next, 1,445 g (5.5 mol) of 4,4'-dicyclohexylmethane diisocyanate and 2.6 g of dibutyltin dilaurate (catalyst) were added and heated to 90°C, and a urethane reaction was carried out over 5 hours to obtain an isocyanate-terminated urethane prepolymer. The reaction mixture was cooled to 80°C, and 149g of triethylamine was added and mixed. From the mixture, 4,340g was taken out and added to a mixed solution of 5,400g of water and 15g of triethylamine under strong stirring. Next, 1,500g of ice was added, and 626g of a 35% aqueous solution of 2-methyl-1,5-pentanediamine was added to carry out a chain extension reaction. The solvent was distilled off so that the solid content concentration became 30% by mass, and polycarbonate urethane resin emulsion 2 having a structure derived from alicyclic diisocyanate was obtained. The glass transition temperature of the obtained polycarbonate-based urethane resin emulsion 2 was measured and found to be 55°C. The volume average particle size was also found to be 55nm.

[0129] <Acrylic resin emulsion synthesis example 1> In a reaction vessel equipped with a stirrer, reflux condenser, dropping device, and thermometer, 900g of ion-exchanged water and 1g of sodium lauryl sulfate were charged, and the temperature was raised to 70°C while stirring and replacing with nitrogen. The internal temperature was kept at 70°C, and 4g of potassium persulfate was added as a polymerization initiator. After dissolution, an emulsion was prepared by adding 450g of ion-exchanged water, 3g of sodium lauryl sulfate, 20g of acrylamide, 365g of styrene, 545g of butyl acrylate, and 10g of methacrylic acid under stirring, and was continuously dropped into the reaction solution over 4 hours. After the dropwise addition was completed, the emulsion was aged for 3 hours. The aqueous emulsion obtained was cooled to room temperature, and then ion-exchanged water and an aqueous sodium hydroxide solution were added to adjust the solid concentration to 30% by mass and the pH to 8, to obtain acrylic resin emulsion 1. The glass transition temperature of the obtained acrylic resin emulsion 1 was measured and found to be 86°C. The volume average particle size was 158nm.

[0130] <Acrylic resin emulsion synthesis example 2> A reaction vessel equipped with a stirrer, a reflux condenser, a dropping device, and a thermometer was charged with 900 g of ion-exchanged water and 1 g of sodium lauryl sulfate, and the temperature was raised to 70° C. while stirring and replacing with nitrogen. The internal temperature was kept at 70°C, and 4g of potassium persulfate was added as a polymerization initiator. After dissolution, an emulsion was prepared by adding 568g of 2-ethylhexyl acrylate and 447g of methyl methacrylate to 450g of ion-exchanged water and 3g of sodium lauryl sulfate while stirring, and then continuously dripped into the reaction solution over 4 hours. After dripping was completed, the mixture was aged for 3 hours. The aqueous emulsion obtained was cooled to room temperature, and then ion-exchanged water and an aqueous sodium hydroxide solution were added to adjust the solid content concentration to 30% by mass and the pH to 8, to obtain acrylic resin emulsion 2. The glass transition temperature of the obtained acrylic resin emulsion 2 was measured and found to be -21°C. The volume average particle size was 152nm.

[0131] <Measurement of glass transition temperature> The glass transition temperature of the resin particles was measured using a DSC system Q-2000 (manufactured by TA Instruments). Specifically, the resin particle dispersion was heated and dried in an oven at 70°C for 12 hours or more, 5 mg of solid content was placed in an aluminum sample container and set in the device, and measurements were performed under the following measurement conditions (1) to (4) under a nitrogen stream. The DSC curve at the second temperature rise was selected, and the glass transition temperature was determined by the midpoint method. The results are shown in Tables 1 and 2 below. Note that the unit of each number for the glass transition temperature in Tables 1 and 2 below is "°C". (1) Cool to -70℃ and hold for 5 minutes (2) Heat up to 120°C at 10°C / min (3) Cool to -70℃ and hold for 5 minutes (4) Heat up to 120°C at 10°C / min

[0132] <Volume average particle size measurement> The volume average particle size was measured using a Microtrac UPA-150 manufactured by Nikkiso Co., Ltd., using a sample diluted with pure water so that the resin particle concentration (mass concentration) in the measurement sample was 0.01 mass %.

[0133] <Preparation example of ink A> Ink A was prepared by adding ion-exchanged water to the ink formulation below so that the total amount became 100 parts by mass, mixing and stirring, and filtering through a filter having an average pore size of 5 μm (Minisart, manufactured by Sartorius). [Ink formula] The above black pigment dispersion: 20 parts by weight Polyester-based urethane resin 1 (volume average particle size: 69 nm): 4 parts by weight Polycarbonate-based urethane resin emulsion 3 (manufactured by Mitsui Chemicals, Inc., product name: Takelac W6110, volume average particle size: 41 nm): 5 parts by mass SAG503A (manufactured by Nissin Chemical Industry Co., Ltd., silicone surfactant, HLB value: 11): 1 part by weight 1,3-propanediol (Dupont): 3 parts by weight 3-Methyl-1,3-butanediol (product name: isoprene glycol, manufactured by Kuraray Co., Ltd.): 25 parts by mass Glycerin (manufactured by Sakamoto Pharmaceutical Co., Ltd.): 2 parts by weight Proxel LV (Avecia, antiseptic and antifungal agent): 0.1 parts by weight Ion exchange water: remaining amount (total: 100 parts by mass)

[0134] <Preparation examples of Ink B to Ink P> Inks B to P were prepared in the same manner as in Preparation Example of Ink A, except that the ink formulations in Preparation Example of Ink A were changed to those shown in Tables 1 and 2. The resin contents in Tables 1 and 2 are solid content amounts. The details of each component in Tables 1 and 2 are as follows: 1,2-Propanediol (product name: propylene glycol, manufactured by ADEKA Corporation) 1,4-Butanediol (Tokyo Chemical Industry Co., Ltd.) 2,3-Butanediol (Tokyo Chemical Industry Co., Ltd.) 1,5-Pentanediol (Tokyo Chemical Industry Co., Ltd.) 3-Methoxy-3-methyl-1-butanol (product name: Solfit, manufactured by Kuraray Co., Ltd.) Triethylene glycol monobutyl ether (Tokyo Chemical Industry Co., Ltd.) SAG002 (Nissin Chemical Industry Co., Ltd., silicone surfactant, HLB value: 12) SAG005 (Nissin Chemical Industry Co., Ltd., silicone surfactant, HLB value: 7) TEGO Twin4000 (Evonic, silicone surfactant) FS-300 (Dupont, fluorosurfactant) Cyan pigment dispersion Magenta pigment dispersion Yellow pigment dispersion Polyester-based urethane resin 2 Polyether-based urethane resin Polycarbonate-based urethane resin 1 Polycarbonate-based urethane resin 2 Acrylic resin emulsion 1 Acrylic resin emulsion 2

[0135] <Ink viscosity measurement> The viscosity of the inks was measured using a viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) under the following conditions. The measurement results of the viscosity of each ink are shown in Tables 1 and 2. [Measurement conditions] Cone rotor: Standard cone rotor (1°34'×R24) Sample volume: 1.2mL Rotation speed: 50 rpm Measurement time: 3 min Temperature: 25℃, 36℃

[0136] <Example 1> To prepare the print, ink A was filled into an ink tank mounted on Ri100 (manufactured by Ricoh Co., Ltd.) and printing was performed on HP Light Fabric (a polyester fabric). Printing conditions were as follows: substrate: T-shirt, fast mode, 100% gradation solid color image was printed while heating was performed at 55.0°C using a silicon rubber heater (first drying step). After that, the surface of the substrate onto which the ink was ejected was heated at a heating temperature of 100.0°C for 3 minutes using a hot air drying unit (second drying step).

[0137] <Examples 2 to 13 and Comparative Examples 1 to 6> Printing was performed in the same manner as in Example 1, except that ink A in Example 1 was changed to ink B to ink P as shown in Tables 3 and 5.

[0138] <Measuring the time it takes for the ink on the printed material to become 0.1μl> For each combination of ink and printing substrate in Examples 1 to 13 and Comparative Examples 1 to 6, the time it took for the ink to reach 0.1 μl when placed on the printing substrate was measured under the following conditions. The measurement results are shown in Tables 1 and 2. [Measurement conditions] Evaluation device: Dmo-5-1 (manufactured by Kyowa Interface Science Co., Ltd.) Measurement method: Droplet method Syringe needle: Teflon (registered trademark) needle (inner diameter: 0.37 μm) Temperature: 25℃ Measurement interval: 0.1 sec Ink drop volume: 2.5μl Contact angle analysis method: θ / 2 method Printed material: HP Light Fabric

[0139] In Examples 1 to 13 and Comparative Examples 1 to 6, "bleeding," "drying property," and "ejection stability" were evaluated. The results are shown in Tables 3 to 5.

[0140] <Bleeding> In Examples 1 to 13 and Comparative Examples 1 to 6, the inks containing the black pigment dispersion were replaced with a cyan pigment dispersion, the inks containing the cyan pigment dispersion were replaced with a magenta pigment dispersion, the inks containing the magenta pigment dispersion were replaced with a yellow pigment dispersion, and the inks containing the yellow pigment dispersion were replaced with a black pigment dispersion. The inks A to P were printed with and before replacement, and the bleeding at the color boundary of the obtained images was visually evaluated. A rating of B or higher was deemed practical. [Evaluation Criteria] A: No bleeding at all at color boundaries B: Slight color bleeding is observed in 5 or fewer places. C: Slight color bleeding is observed in 10 or fewer places. D: Severe bleeding is observed, degrading image quality.

[0141] <Drying> Using the inkjet printer, a deposition amount of 1.5 g / m 2 After printing, the product was placed in a dryer at 100°C, and the drying time was varied. The print was removed and the solid area was touched to check whether transfer occurred. The drying time until no transfer occurred was used to evaluate the drying performance according to the following evaluation criteria. A rating of C or higher is deemed practical. [Evaluation Criteria] A: If the drying time is less than 15 seconds, the transfer will not occur. B: If the drying time is between 15 and 30 seconds, the transfer will not occur. C: If the drying time is between 30 and 45 seconds, the transfer will not occur. D: The transfer does not disappear even if the drying time is 45 seconds or more.

[0142] <Discharge stability> After printing a 15cm x 20cm solid image on the printing substrate, a chart that can identify nozzle clogs, which is installed in the inkjet printer, was printed to check the number of nozzle clogs. The ejection stability was evaluated based on the ratio of the number of nozzle clogs to the total number of nozzles, according to the following evaluation criteria. A rating of B or higher indicates that the ink is usable. [Evaluation Criteria] A: Less than 5% B: 5% or more but less than 10% C: 10% to less than 15% D: 15% or more

[0143] [Table 1]

[0144] [Table 2]

[0145] [Table 3]

[0146] [Table 4]

[0147] [Table 5]

[0148] Examples of aspects of the present invention include the following. <1> A discharge step of discharging ink onto a substrate; a first drying step of heating a surface of the printing substrate on which the ink is not ejected to dry the ink; a second drying step of heating the surface of the printing substrate onto which the ink has been ejected to dry the ink; the heating temperature T1 (°C) in the first drying step and the heating temperature T2 (°C) in the second drying step satisfy inequality (1); 0(℃)≦T2-T1≦90(℃)...Inequality (1) the ink contains an organic solvent A having a boiling point of less than 250° C., an organic solvent B having a boiling point of 250° C. or more, and a resin; the content of the organic solvent A is 30% by mass or less relative to the ink, the content of the organic solvent B is 1% by mass or more and 3% by mass or less with respect to the ink, The content of the resin in the ink is 5% by mass or more and 15% by mass or less, the viscosity of the ink at 25°C is 8.0 mPa s or more and 11.0 mPa s or less; the viscosity of the ink at 36°C is 5.5 mPa s or more and 11.0 mPa s or less; This printing method is characterized in that the time it takes for a droplet of the ink having a volume of 2.5 μL ejected onto the substrate to reduce to a volume of 0.1 μL or less is 10.0 seconds or less at 25° C. <2> The T1 (°C) is 20°C or more and 70°C or less. <1> 2 is a printing method according to the present invention. <3> In the second drying step, the surface of the printing material onto which the ink is discharged is heated by at least one of a hot air heater and an infrared (IR) heater. <1> from <2> 13. The printing method according to claim 12, wherein <4> The resin contains one or more kinds of resin particles having a glass transition temperature of 0° C. or lower. <1> from <3> 13. The printing method according to claim 12, wherein <5> The resin particles are urethane resin particles. <4> 2 is a printing method according to the present invention. <6> The content of the resin particles is 30% by mass or more and 70% by mass or less with respect to the resin. <4> from <5> 13. The printing method according to claim 12, wherein <7> The organic solvent B is glycerin. <1> from <6> 13. The printing method according to claim 12, wherein <8> The ink contains a silicone surfactant. <1> from <7> 13. The printing method according to claim 12, wherein <9> The silicone surfactant is a polyoxyalkylene-modified dimethylpolysiloxane represented by the following chemical formula 1: <8> 2 is a printing method according to the present invention. [ka] (chemical formula 1) (In Chemical Formula 1, m represents an integer of 0 to 10, n represents an integer of 1 to 5, a represents an integer of 0 to 20, b represents an integer of 0 to 20, R represents any one of an alkyl group and an alkylene group having 1 to 10 carbon atoms, and R' represents any one of a hydrogen atom, an alkyl group and an alkylene group having 1 to 10 carbon atoms.) <10> The silicone surfactant has an HLB value of 8.0 or more and 11.5 or less, calculated by the Griffin method. <9> 2 is a printing method according to the present invention. <11> The content of the silicone surfactant is 0.5% by mass or more and 1.5% by mass or less. <8> from <10> 13. The printing method according to claim 12, wherein <12> an ink containing means for containing the ink, which contains 30 mass % or less of an organic solvent A having a boiling point of less than 250°C, 1 mass % to 3 mass % of an organic solvent B having a boiling point of 250°C or more, and 5 mass % to 15 mass % of a resin, and which has a viscosity of 8.0 mPa·s to 11.0 mPa·s at 25°C and a viscosity of 5.5 mPa·s to 11.0 mPa·s at 36°C, and which takes 10.0 seconds or less at 25°C for a droplet of ink having a volume of 2.5 μL ejected onto a substrate to reduce in volume to 0.1 μL or less; a discharge means including a nozzle having a discharge port on a nozzle surface for discharging the ink toward the printing material; a first drying means for heating a surface of the printing material on which the ink is not ejected, to dry the ink; and a second drying means for heating the surface of the printing material onto which the ink has been ejected, to dry the ink, The printing device is characterized in that the heating temperature T1 (° C.) of the first drying means and the heating temperature T2 (° C.) of the second drying means satisfy inequality (1). 0(℃)≦T2-T1≦90(℃)...Inequality (1)

[0149] The above <1> from <11> The printing method according to any one of the preceding claims, <12> The printing apparatus described in the above is capable of solving the above-mentioned problems in the prior art and achieving the object of the present invention. [Prior art documents] [Patent documents]

[0150] [Patent Document 1] JP 2019-163380 A [Patent Document 2] JP 2005-144966 A [Explanation of symbols]

[0151] 1 Printing device 20 Recording head 400 Image forming device 401 Exterior of image forming device 401c Device body cover 404 Cartridge Holder 410 Main Tank 410k Black (K) main tank 410c Cyan (C) main tank 410m Magenta (M) main tank 410y Yellow (Y) main tank 411 Ink storage unit 413 Ink outlet 414 Storage container case 420 Mechanism Department 434 Discharge Head 436 Supply Tube

Claims

1. A discharge step of discharging ink onto a substrate; a first drying step of heating a surface of the printing substrate on which the ink is not ejected to dry the ink; a second drying step of heating the surface of the printing substrate onto which the ink has been ejected to dry the ink; the heating temperature T1 (° C.) in the first drying step and the heating temperature T2 (° C.) in the second drying step satisfy inequality (1), 0 (℃)≦T2-T1≦90 (℃)...Inequality (1) the ink contains an organic solvent A having a boiling point of less than 250° C., an organic solvent B having a boiling point of 250° C. or more, and a resin; the content of the organic solvent A is 30% by mass or less with respect to the ink, the content of the organic solvent B is 1% by mass or more and 3% by mass or less with respect to the ink, the content of the resin is 5% by mass or more and 15% by mass or less with respect to the ink, The resin contains one or more types of resin particles having a glass transition temperature of 0° C. or lower, The viscosity of the ink at 25° C. is 8.0 mPa·s or more and 11.0 mPa·s or less, The viscosity of the ink at 36° C. is 5.5 mPa·s or more and 11.0 mPa·s or less, A printing method, characterized in that the time required for a droplet of the ink having a volume of 2.5 μL ejected onto the substrate to reduce to a volume of 0.1 μL or less is 10.0 seconds or less at 25° C.

2. The printing method according to claim 1 , wherein T1 (° C.) is 20° C. or more and 70° C. or less.

3. The printing method according to claim 1 , wherein in the second drying step, the surface of the printing material onto which the ink has been ejected is heated by at least one of a hot air heater and an infrared (IR) heater.

4. The printing method according to claim 3 , wherein the resin particles are urethane resin particles.

5. The printing method according to claim 3 , wherein the content of the resin particles is 30% by mass or more and 70% by mass or less with respect to the resin.

6. The printing method according to claim 1 , wherein the organic solvent B is glycerin.

7. The printing method according to claim 1 , wherein the ink comprises a silicone-based surfactant.

8. The printing method according to claim 7 , wherein the silicone surfactant is a polyoxyalkylene-modified dimethylpolysiloxane represented by the following chemical formula 1: 【Chemistry 1】 (Chemical formula 1) (In Chemical Formula 1, m is an integer from 0 to 10, n is an integer from 1 to 5, a is an integer from 0 to 20, b is an integer from 0 to 20, R is either an alkyl group or an alkylene group having 1 to 10 carbon atoms, and R' is either a hydrogen atom, an alkyl group or an alkylene group having 1 to 10 carbon atoms.)

9. The printing method according to claim 8 , wherein the silicone surfactant has an HLB value of 8.0 or more and 11.5 or less, as calculated by the Griffin method.

10. The printing method according to claim 7 , wherein the content of the silicone surfactant is from 0.5% by mass to 1.5% by mass.

11. an ink containing means for containing the ink, the ink containing 30 mass % or less of an organic solvent A having a boiling point of less than 250°C, 1 mass % or more and 3 mass % or less of an organic solvent B having a boiling point of 250°C or more, and 5 mass % or more and 15 mass % or less of a resin containing one or more kinds of resin particles having a glass transition temperature of 0°C or less, the ink having a viscosity of 8.0 mPa·s or more and 11.0 mPa·s or less at 25°C and a viscosity of 5.5 mPa·s or more and 11.0 mPa·s or less at 36°C, and the time required for a droplet of the ink having a volume of 2.5 μL ejected onto a substrate to reduce in volume to 0.1 μL or less is 10.0 seconds or less at 25°C; a discharge means including a nozzle having a discharge port on a nozzle surface for discharging the ink toward the printing material; a first drying means for heating a surface of the printing material on which the ink is not ejected, to dry the ink; and a second drying means for heating the surface of the printing material onto which the ink has been ejected, to dry the ink, A printing apparatus, wherein a heating temperature T1 (° C.) of the first drying means and a heating temperature T2 (° C.) of the second drying means satisfy inequality (1). 0 (℃)≦T2-T1≦90 (℃)...Inequality (1)

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