Inkjet printing apparatus and inkjet printing method

Abstract

To provide an ink jet printer which has the excellent glossiness difference between low gloss (matte tone) and high gloss (gloss tone), scratch resistance, weather resistance and drying property.SOLUTION: An ink jet printer comprises: an ink storage part which stores ink; a discharge head which discharges the ink; and heating means which heats a printing object. The ink jet printer includes: a low gloss printing mode being the printing mode for applying low gloss, and a high gloss printing mode being the printing mode for applying high gloss. The heating means, when the temperature of the printing object in a low gloss printing region printed in the low gloss printing mode in a case where non-aqueous clear ink is made to adhere to the printing object is Tmatte (°C), and the temperature of the printing object in a high gloss printing region printed in the high gloss printing mode in a case where the non-aqueous clear ink is made to adhere to the printing object is Tgloss (°C), heats the printing object so as to satisfy the formula: Tmatte>Tgloss. The ink has the non-aqueous clear ink which contains a resin, an organic solvent, and water; and aqueous ink which contains the resin, the organic solvent and water. The content of the resin contained in the aqueous ink is equal to or greater than 10 mass%. The organic solvent contained in the aqueous ink includes an organic solvent whose boiling point is equal to or greater than 240°C. The content of the organic solvent whose boiling point is equal to or greater than 240°C is between 1 mass% and 3 mass%.

Description

Technical Field

[0001] The present invention relates to an inkjet printing apparatus and an inkjet printing method.

Background Art

[0002] In recent years, in industrial applications such as wallpapers, advertisements, and signboards, permeable recording media such as textiles and campus fabrics have been used, and various inks used for such permeable recording media have been developed.

[0003] Examples of such inks include solvent-based inks using organic solvents as solvents and ultraviolet curable inks mainly composed of polymerizable monomers, which are widely used. However, there are concerns about the environmental impact due to the evaporation of the organic solvent in the solvent-based ink. In the ultraviolet curable ink, the choice of polymerizable monomers to be used is limited from the viewpoint of safety. Therefore, an ink set containing an aqueous ink with low environmental impact and capable of directly recording on a permeable recording medium has been proposed.

[0004] On the other hand, in an inkjet recording apparatus, those having a gloss control function have been developed. For example, a liquid ejection head capable of ejecting ink containing thermoplastic resin particles from a nozzle toward a landing target, and heating means for heating the ink droplets landed on the landing target are provided, and the heating means controls the degree of film formation on the surface of the ink droplets by heating at a film formation control temperature corresponding to the minimum film formation temperature at which film formation on the surface of the ink droplets starts. A liquid ejection apparatus has been proposed (see, for example, Patent Document 1).

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide an inkjet printing apparatus excellent in the gloss difference between low gloss (mat finish) and high gloss (gloss finish), rubbing resistance, weather resistance, and drying property.

Means for Solving the Problems

[0006] The inkjet printing apparatus of the present invention as a means for solving the above problems is an inkjet printing apparatus having an ink storage unit for storing ink, a discharge head for discharging ink, and a heating means for heating a printing object, wherein the inkjet printing apparatus has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss, and when the heating means prints in the low gloss printing mode when attaching the non-aqueous clear ink to the printing object, the temperature of the printing object in the low gloss printing area is T matte (°C), and when printing in the high gloss printing mode when attaching the non-aqueous clear ink to the printing object, the temperature of the printing object in the high gloss printing area is T gloss (°C), then the following formula, T matte >T gloss is satisfied for heating, and the ink has a non-aqueous clear ink containing a resin and an organic solvent and an aqueous ink containing a resin, an organic solvent and water, the content of the resin contained in the aqueous ink is 10% by mass or more, the organic solvent contained in the aqueous ink contains an organic solvent having a boiling point of 240°C or higher, and the content of the organic solvent having a boiling point of 240°C or higher is 1% by mass or more and 3% by mass or less.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide an inkjet printing apparatus excellent in the gloss difference between low gloss (mat finish) and high gloss (gloss finish), scratch resistance, weather resistance, and drying property.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0009] (Inkjet Printing Apparatus and Inkjet Printing Method) The inkjet printing apparatus of the present invention is an inkjet printing apparatus having an ink storage unit for storing ink, a discharge head for discharging ink, and a heating means for heating a printing object, wherein the inkjet printing apparatus has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss, and the heating means heats the printing object in the low gloss printing area when printing in the low gloss printing mode in which the non-aqueous clear ink is adhered to the printing object to a temperature of T matte (°C), and heats the printing object in the high gloss printing area when printing in the high gloss printing mode in which the non-aqueous clear ink is adhered to the printing object to a temperature of T gloss (°C), and heats so as to satisfy the following formula, T matte > T gloss and has a non-aqueous clear ink containing a resin and an organic solvent and an aqueous ink containing a resin, an organic solvent, and water, and the content of the resin contained in the aqueous ink is 10% by mass or more, and the organic solvent contained in the aqueous ink contains an organic solvent having a boiling point of 240°C or higher, and the content of the organic solvent having a boiling point of 240°C or higher is 1% by mass or more and 3% by mass or less, and further has other means as required.

[0010] The inkjet printing apparatus of the present invention can obtain a printed matter having a low gloss (mat) printing area and a high gloss (gloss) printing area by using a non-aqueous clear ink containing a resin and an organic solvent. Further, the inkjet printing apparatus of the present invention can form an image using an aqueous ink containing a resin, an organic solvent, and water, and the content of the resin contained in the aqueous ink being 10% by mass or more can improve weather resistance and scratch resistance. Further, the inkjet printing apparatus of the present invention can improve weather resistance and scratch resistance because the aqueous ink contains an organic solvent having a boiling point of 240°C or higher and the content of the organic solvent having a boiling point of 240°C or higher is 1% by mass or more and 3% by mass or less.

[0011] The inkjet printing apparatus of the present invention is an inkjet printing apparatus having an ink storage unit for storing ink, a discharge head for discharging ink, and heating means for heating a printing material, wherein the inkjet printing apparatus has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss, and the temperature of the heating means in the low gloss printing mode is HT matte (°C), and the temperature of the heating means in the high gloss printing mode is HT gloss (°C). When heated so as to satisfy the following formula: HT matte > HT gloss , the ink includes a non-aqueous clear ink containing a resin and an organic solvent, and an aqueous ink containing a resin, an organic solvent, and water. The content of the resin contained in the aqueous ink is 10% by mass or more, the organic solvent contained in the aqueous ink includes an organic solvent having a boiling point of 240°C or higher, and the content of the organic solvent having a boiling point of 240°C or higher is 1% by mass or more and 3% by mass or less. Further, other means are provided as required.

[0012] The inkjet printing method of the present invention includes a step of applying an aqueous ink containing 10% by mass or more of a resin, 1% by mass or more and 3% by mass or less of an organic solvent having a boiling point of 240°C or higher, and water to a printing material to form a printing layer, a step of applying a non-aqueous clear ink containing a resin and an organic solvent to the printing material, and a heating step of heating the printing material by heating means. The method has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss. In the heating step, when the non-aqueous clear ink is adhered to the printing material, the temperature of the printing material in the low gloss printing area printed in the low gloss printing mode is T matte (°C), and the temperature of the printing material in the high gloss printing area printed in the high gloss printing mode when the non-aqueous clear ink is adhered to the printing material is T gloss (°C). When heated so as to satisfy the following formula: T matte > T gloss , and further includes other steps as required.

[0013] The inkjet printing method of the present invention includes a step of applying an aqueous ink containing 10% by mass or more of a resin, 1% by mass or more and 3% by mass or less of an organic solvent having a boiling point of 240°C or higher, and water to a printing object to form a printing layer, a step of applying a non-aqueous clear ink containing a resin and an organic solvent to the printing object, and a heating step of heating the printing object by heating means. It has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss. The temperature of the heating means in the low gloss printing mode is HT matte (°C), and the temperature of the heating means in the high gloss printing mode is HT gloss (°C). Then, the following formula, HT matte >HT gloss is satisfied, and further includes other steps as required.

[0014] Conventionally, in an inkjet recording apparatus using a clear ink (UV clear ink) that cures by irradiation with ultraviolet rays, a gloss control method has been proposed in which gloss can be controlled to low gloss (mat finish) or high gloss (gloss finish) by controlling the amount of irradiation light. However, the problem with UV clear ink is that it has a strong odor, and the odor remains on the printed matter, so it is not suitable for printed matter for indoor use. For this reason, the installation location of the inkjet printing apparatus also requires an environment where exhaust can be performed, and the installation location is limited. In addition, UV clear ink requires an ultraviolet irradiation device, and there are problems such as an increase in the size and cost of the device.

[0015] In the prior art of Patent Document 1, when printing with an aqueous ink on a permeable recording medium, there is a problem that high-gloss printing cannot be performed because the aqueous ink penetrates into the fabric. Also, when using an ink with improved drying properties to increase productivity, there is a problem that the ink film adheres to the surface of the printing object, resulting in poor rub resistance. The inkjet printing apparatus and inkjet printing method of the present invention are based on the finding that in the prior art of Patent Document 1, by using a color ink containing a coloring material and heating it by a heating means at a film-forming control temperature corresponding to the minimum film-forming temperature at which film formation on the surface of ink droplets starts, the degree of film formation on the surface of the ink droplets is controlled to adjust the glossiness. However, compared with a clear ink not containing a coloring material, a sufficient glossiness difference cannot be obtained with a color ink containing a coloring material, and it cannot cope with both low gloss (mat finish) and high gloss control.

[0016] The inkjet printing apparatus and inkjet printing method of the present invention perform both high gloss (gloss finish) and low gloss (mat finish) control by controlling the heating temperature using a non-aqueous clear ink containing a resin and an organic solvent. When applying low gloss (mat), printing is performed at a higher temperature compared to the high gloss (glossy) application mode. Since the printing temperature is high, in the non-aqueous clear ink containing a resin, the spreading of the dots is suppressed, the coalescence of adjacent dots is suppressed, and dots with a high dot height (pile height) are formed. These dots form surface irregularities and impart low gloss (mat gloss). When applying high gloss, printing is performed at a lower temperature compared to the low gloss application mode. Since the printing temperature is low, in the non-aqueous clear ink containing a resin, the spreading of the dots and the coalescence of adjacent dots are promoted to form a smooth surface, and high gloss (glossy) is imparted.

[0017] Image formation can be performed using an aqueous ink containing a resin, an organic solvent, and water. It is preferable to perform printing using an aqueous resin ink having a coloring material as a color ink. By performing high gloss (gloss finish) printing on the surface of a recording medium previously printed with a color ink, the layer of the non-aqueous clear ink covers the surface of the object to be printed, and the abrasion resistance is improved.

[0018] The inkjet printing apparatus of the present invention uses a non-aqueous clear ink containing a resin and an organic solvent, and has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss. When the heating means prints in the low gloss printing mode when the non-aqueous clear ink is attached to the object to be printed, the temperature of the object to be printed in the low gloss (mat) printing area is T matte (°C), and when the heating means prints in the high gloss printing mode when the non-aqueous clear ink is attached to the object to be printed, the temperature of the object to be printed in the high gloss (gloss) printing area is T gloss (°C). Then, by heating so as to satisfy the following formula, T matte >T gloss (i.e., by heating so as to satisfy the following formula), or by setting the temperature of the heating means in the low gloss printing mode to HT matte (°C) and the temperature of the heating means in the high gloss printing mode to HT gloss (°C), then, by satisfying the following formula, HT matte >HT gloss (i.e., by satisfying the following formula), it is possible to cope with the gloss control of both low gloss (mat finish) and high gloss (gloss finish).

[0019] The heating means of the inkjet printing apparatus of the present invention heats the object to be printed so as to satisfy the following formula, T matte >T gloss (i.e., by heating so as to satisfy the following formula), and it is preferable to heat so as to satisfy the following formula, T matte -T gloss ≧10 °C, and it is more preferable to heat so as to satisfy the following formula, T matte -T gloss ≧20 °C. Further, as the temperature HT (°C) of the heating means, when the temperature of the heating means in the low gloss printing mode is HT matte (°C) and the temperature of the heating means in the high gloss printing mode is HT gloss (°C), then, by satisfying the following formula, HT matte >HT gloss (i.e., by satisfying the following formula), and it is preferable to satisfy HT matte >HT gloss ≧10 °C, and it is preferable to satisfy HT matte >HT glossIt is more preferable to satisfy ≧20°C. Thereby, in the low gloss printing mode, the heating temperature is increased to suppress the wet spreading of dots, form dots with a high pile height, and form a surface with large irregularities. On the other hand, in the high gloss printing mode, the heating temperature is lowered to promote the wet spreading of dots, and a smooth surface can be formed by the coalescence of adjacent dots. The temperature HT (°C) of the heating means is not particularly limited and can be appropriately selected according to the purpose. For example, the set temperature of the heating means can be used.

[0020] The temperature T of the object to be printed in the printing section in the low gloss printing mode matte (°C) is preferably 50°C or higher, and more preferably 50°C or higher and 80°C or lower. The temperature T of the object to be printed in the printing section in the high gloss printing mode gloss (°C) is preferably 70°C or lower, and more preferably 60°C or lower. For the temperature HT of the heating means in the low gloss printing mode matte (°C) is preferably 50°C or higher, and more preferably 50°C or higher and 80°C or lower. For the temperature HT of the heating means in the high gloss printing mode gloss (°C) is preferably 70°C or lower, and more preferably 60°C or lower. By setting such a temperature range, a large change in glossiness can be realized in each printing mode using the non-aqueous clear ink. The temperature of the object to be printed in the printing section can be measured, for example, by installing a thermocouple on the recording medium as the object to be printed and directly measuring the recording medium temperature, measuring the temperature of the heater that heats the recording medium and using it as the recording medium temperature, measuring the temperature around the recording medium non-contactingly with a radiation thermometer, etc. and using it as the recording medium temperature.

[0021] In the present invention, the printing rate of the low gloss (mat) printing image printed in the low gloss printing mode is D matte and the printing rate of the high gloss (gloss) printing image printed in the high gloss printing mode is D gloss Then, the following formula, D gloss >D matte is preferably satisfied, and the following formula, D gloss -D matteIt is more preferable to satisfy >10%. Since a smoother surface is more likely to be formed when the printing rate is higher, an image with a high printing rate is used in the high-gloss printing mode. On the other hand, in the low-gloss printing mode, if the printing rate is high, coalescence of adjacent dots occurs and it becomes difficult to form surface irregularities, so an image with a low printing rate is used. Here, the printing rate means the following printing rate (%) = number of clear ink printed dots / (vertical resolution × horizontal resolution) × 100 (wherein, in the above formula, the "number of clear ink printed dots" is the number of dots where clear ink has actually been printed per unit area, and the "vertical resolution" and "horizontal resolution" are the resolutions per unit area respectively. When clear ink is printed in layers so as to be at the same dot position, the "number of clear ink printed dots" is represented by the total number of dots where clear ink has actually been printed per unit area.) Note that a printing rate of 100% means the maximum ink weight of a single color with respect to a pixel.

[0022] <ink storage section> The ink storage section stores a non-aqueous clear ink and an aqueous ink. The ink storage section is not particularly limited as long as it is a member capable of storing ink, and can be appropriately selected according to the purpose. For example, an ink storage container, an ink tank, etc. can be mentioned. The ink storage container contains the non-aqueous clear ink and the aqueous ink in the container, and further has other members appropriately selected as necessary. The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, those having at least an ink bag formed of an aluminum laminate film, a resin film, etc. can be mentioned. Examples of the ink tank include a main tank and a sub-tank.

[0023] <discharge head> The discharge head applies ink to the object to be printed to form a printing layer. The discharge head has a nozzle plate, a pressure chamber, and a stimulation generating means.

[0024] -Nozzle plate- The nozzle plate has a nozzle substrate and a repellent ink film on the nozzle substrate.

[0025] -Pressurizing chamber- The pressurizing chamber is a plurality of individual flow paths that are individually arranged corresponding to the plurality of nozzle holes provided in the nozzle plate and communicate with the nozzle holes, and may also be referred to as an ink flow path, a pressurized liquid chamber, a pressure chamber, a discharge chamber, a liquid chamber, etc.

[0026] -Stimulation generation means- The stimulation generation means is a means for generating stimulation applied to the ink. The stimulation in the stimulation generation means is not particularly limited and can be appropriately selected according to the purpose. For example, heat (temperature), pressure, vibration, light, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, heat (temperature) and pressure are preferred. The stimulation generation means is not particularly limited and can be appropriately selected according to the purpose. For example, a heating device, a pressurizing device, a piezoelectric element, a vibration generation device, an ultrasonic oscillator, light, etc. can be mentioned. Specifically, as the stimulation generation means, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes the phase change due to the boiling of the ink film using an electrothermal conversion element such as a heating resistor, a shape memory alloy actuator that uses a metal phase change due to a temperature change, an electrostatic actuator that uses electrostatic force, etc. can be mentioned.

[0027] When the stimulation is "heat", heat energy corresponding to the recording signal is applied to the ink in the ink ejection head using, for example, a thermal head or the like. Examples of the method include generating bubbles in the ink by the heat energy and ejecting the ink as droplets from the nozzle holes of the nozzle plate by the pressure of the bubbles. When the stimulus is "pressure", for example, by applying a voltage to the piezoelectric element adhered to a position called the pressure chamber in the ink flow path in the ink ejection head, the piezoelectric element bends. As a result, the volume of the pressure chamber contracts, and a method of ejecting the ink as droplets from the nozzle holes of the ink ejection head can be mentioned, etc. Among these, the piezo method of applying a voltage to the piezo element to fly the ink is preferable.

[0028] <Heating means> The heating means heats the object to be printed. As the heating means, means for heating and drying the printing surface or the back surface of the recording medium as the object to be printed is included. The heating means is not particularly limited and can be appropriately selected according to the purpose. For example, an infrared heater, a warm air heater, a heating roller, etc. can be mentioned. These may be used alone or in combination of two or more.

[0029] The method of drying the recording medium as the object to be printed is not particularly limited and can be appropriately selected according to the purpose. For example, a method of bringing a heated fluid such as warm air as a drying means into contact with the recording medium to which the ink is applied, a method of bringing the recording medium to which the ink is applied into contact with a heating member and heating by heat transfer, a method of heating the recording medium to which the ink is applied by irradiating energy rays such as infrared rays and far-infrared rays, etc. can be mentioned. The heating can be performed at least in any one of before printing, during printing, and after printing. By heating before printing and during printing, it becomes possible to print on a heated medium, and by heating after printing, the printed matter can be dried. The heating time is not particularly limited as long as the surface temperature of the recording medium can be controlled to a desired temperature, and can be appropriately selected according to the purpose. The control of the heating time is preferably performed by controlling the conveyance speed of the recording medium as the object to be printed.

[0030] <Non-aqueous clear ink> The non-aqueous clear ink is a colorless and transparent non-aqueous ink that substantially does not contain a coloring material and water, and means an ink containing an organic solvent as a solvent. Substantially not containing a coloring material means that the content of the coloring material is less than 0.5% by mass, and substantially not containing water means that the content of water is less than 1% by mass. The non-aqueous clear ink can contain a coloring material and water as impurities. The non-aqueous clear ink preferably contains a resin and an organic solvent, and preferably contains a surfactant, and further contains other components as required.

[0031] <Resin> There is no particular limitation on the resin, and it can be appropriately selected according to the purpose. For example, polyurethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic-styrene resin, acrylic-silicone resin, etc. can be mentioned. When manufacturing the ink, it is preferably added as resin particles composed of these resins. The resin particles may be added to the ink in the state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those appropriately synthesized or commercially available products may be used. These may be used alone or in combination of two or more types of resin particles.

[0032] As the resin, non-aqueous emulsion-type polymer particles can also be used as the resin. Non-aqueous emulsion-type polymer particles are a dispersion liquid in which particles such as polyurethane resin, acrylic resin, and acrylic polyol resin are stably dispersed in an organic solvent. There is no particular limitation on the non-aqueous emulsion-type polymer particles, and they can be appropriately selected according to the purpose. For example, polyurethane resins such as "Sunprene IB-501" and "Sunprene IB-F370" manufactured by Sanyo Chemical Industries, Ltd., and acrylic polyol resins such as "N-2043-60MEX" and "N-2043-AF-1" manufactured by Harima Chemicals, Inc. can be mentioned.

[0033] As the content of the resin contained in the non-aqueous clear ink, 9% by mass or more is preferable, and 9% by mass or more and 25% by mass or less is more preferable. When the content is 9% by mass or more, even with a small amount of non-aqueous clear ink, low gloss (mat gloss) and high gloss (glossy gloss) can be controlled. When the content is 25% by mass or less, the ejection stability of the ink is improved.

[0034] A printed matter with low gloss (mat gloss) is realized by forming isolated dots with a high dot ball height (pile height), imparting unevenness to the surface, and making it low gloss (mat finish). When the content of the resin in the non-aqueous clear ink is large, dots with a high pile height are likely to be formed, which is preferable in terms of easily obtaining a printed matter with low gloss. On the other hand, a printed matter with high gloss (glossy gloss) is given smoothness by filling the surface unevenness with the non-aqueous clear ink to form a smooth surface. To fill the surface unevenness with the non-aqueous clear ink, it is preferable that the content of the resin in the non-aqueous clear ink is large, because the surface unevenness can be filled with a small amount of non-aqueous clear ink, and a printed matter with high gloss can be easily obtained.

[0035] <Organic solvent> The organic solvent is not particularly limited and can be appropriately selected according to the purpose. For example, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, isopropyl alcohol, and fluorinated alcohol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, carboxylic acid esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, and ethyl propionate, ethers such as diethyl ether, dipropyl ether, alkylene glycol ether compounds, tetrahydrofuran, and dioxane can be mentioned. These may be used alone or in combination of two or more. Among these, from the point of being liquid under normal temperature and pressure, it is preferable to contain one or more of an alkylene glycol ether compound, an alkylene glycol monoether compound, and a lactone compound.

[0036] The alkylene glycol ether compound is not particularly limited and can be appropriately selected according to the purpose. For example, aliphatic groups such as methyl, n-propyl, i-propyl, n-butyl, i-butyl, hexyl, 2-ethylhexyl, allyl having a double bond, and ethylene glycol ethers and propylene glycol ethers based on each group of phenyl can be mentioned. The alkylene glycol ether compound is colorless and has little odor. Since it has an ether group and a hydroxyl group in the molecule, it is a liquid at room temperature with the characteristics of both alcohols and ethers. In addition, there are a monoether type in which only one hydroxyl group is substituted and a diether type in which both hydroxyl groups are substituted, and these can be used in combination.

[0037] The alkylene glycol monoether compound is not particularly limited and can be appropriately selected according to the purpose. For example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, etc. can be mentioned. These may be used alone or in combination of two or more.

[0038] The alkylene glycol diether compound is not particularly limited and can be appropriately selected according to the purpose. For example, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl 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, etc. may be mentioned. These may be used alone or in combination of two or more.

[0039] The lactone compound is not particularly limited and can be appropriately selected according to the purpose. For example, γ-butyrolactone, δ-valerolactone, ε-caprolactone, etc. may be mentioned. Examples of other non-aqueous solvents include lactate, propylene glycol monomethyl ether acetate (PMA), 2-butoxyethyl acetate (BMGAC), propylene diglycol acetate (PGDA), dipropylene glycol dimethyl ether (DMM), 3-methoxy-n-butyl acetate (MBA), 1-butoxy-2-propanol (PNB), 2-octanone, etc.

[0040] The content of the organic solvent contained in the non-aqueous clear ink is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoints of the drying property and ejection reliability of the ink, 10% by mass or more and 60% by mass or less are preferable, and 20% by mass or more and 60% by mass or less are more preferable.

[0041] <Surfactant> The non-aqueous clear ink preferably contains a surfactant. By adding a surfactant to the ink, the surface tension is reduced, and after the ink droplets land on a recording medium such as paper, the penetration into the recording medium is accelerated, so that feathering and color bleeding can be reduced. Surfactants are classified into nonionic, anionic, and amphoteric types according to the polarity of the hydrophilic group. Also, depending on the structure of the hydrophobic group, they are classified into fluorine-based, silicone-based, acetylene-based, etc. In the present invention, a fluorine-based surfactant is mainly used, but a silicone-based surfactant or an acetylene-based surfactant may be used in combination. The content of the surfactant is preferably 2% by mass or less, more preferably 0.05% by mass or more and 2% by mass or less, and still more preferably 0.1% by mass or more and 2% by mass or less. By setting the content of the surfactant to 2% by mass or less, a large decrease in glossiness can be obtained in the low gloss (matte gloss) printing mode.

[0042] The surfactant is not particularly limited and can be appropriately selected according to the purpose. Examples include silicone-based surfactants, fluorine-based surfactants, amphoteric surfactants, nonionic surfactants, anionic surfactants, etc.

[0043] The silicone-based surfactant is not particularly limited and can be appropriately selected according to the purpose. Examples include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, side-chain and both-end modified polydimethylsiloxane, etc. Examples of those that do not decompose even at high pH include those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group. As the silicone-based surfactant, those synthesized as appropriate may be used, or commercially available products may be used. The commercially available products are not particularly limited and can be appropriately selected according to the purpose. For example, they can be obtained from BYK-Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., etc.

[0044] As the silicone-based surfactant, a polyether-modified silicone-based surfactant can be used. For example, compounds in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylsiloxane can be mentioned. There are no particular restrictions on the polyether-modified silicone-based surfactant, and it can be appropriately selected according to the purpose. For example, those represented by the following general formula (S-1), in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylpolysiloxane, can be mentioned.

[0045] [General formula (S-1)] JPEG0007703964000001.jpg62136(However, in the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.)

[0046] As the polyether-modified silicone-based surfactant, those synthesized as appropriate may be used, or commercially available products may be used. There are no particular restrictions on the commercially available products, and they can be appropriately selected according to the purpose. For example, KF-618, KF-642, KF-643 (manufactured by Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-1906EX (manufactured by Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (manufactured by Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (manufactured by BYK-Chemie GmbH), TSF4440, TSF4452, TSF4453 (manufactured by Toshiba Silicone Co., Ltd.), etc. can be mentioned.

[0047] Examples of the fluorine-based surfactant include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain. These are preferable because they have low foaming properties. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid, perfluoroalkylsulfonate, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid, perfluoroalkylcarboxylate, and the like. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, a salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, and the like. Examples of the counter ion of the salt in the fluorosurfactant include Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2, NH(CH2CH2OH)3, and the like.

[0048] Examples of the amphoteric surfactant include lauryl aminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethylbetaine, and the like.

[0049] Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, ethylene oxide adduct of acetylene alcohol, and the like.

[0050] Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, salts of polyoxyethylene alkyl ether sulfate, and the like. These may be used alone or in combination of two or more.

[0051] As the fluorosurfactant, compounds having 2 to 16 carbon atoms substituted with fluorine are preferred, and compounds having 4 to 16 carbon atoms substituted with fluorine are more preferred. Examples of the fluorosurfactant include perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain. Among these, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain are preferred because of their low foaming property, and compounds represented by the following general formula (F-1) and general formula (F-2) are more preferred.

[0052] [General formula (F-1)] JPEG0007703964000002.jpg21156 In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10, and n is preferably an integer of 0 to 40.

[0053] [General formula (F-2)] CnF 2n+1 -CH2CH(OH)CH2-O-(CH2CH2O)a-Y In the compound represented by the general formula (F-2), Y is H, or C m F 2m+1 where m is an integer of 1 to 6, or CH2CH(OH)CH2-C m F 2m+1 where m is an integer of 4 to 6, or C p H 2p+1 where p is an integer of 1 to 19. n is an integer of 1 to 6. a is an integer of 4 to 14.

[0054] As the fluorosurfactant, a commercially available product may be used. Examples of the commercially available products include Surfron S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.), Fluorad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited), Megafac F-470, F-1405, F-474 (all manufactured by DIC Corporation), Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours), FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (all manufactured by Omnova Solutions Inc.), Uni-Dyn DSN-403N (manufactured by Daikin Industries, Ltd.), and the like. Among these, FS-3100, FS-34, FS-300 manufactured by Chemours, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omnova Solutions Inc., and Uni-Dyn DSN-403N manufactured by Daikin Industries, Ltd. are preferable because they significantly improve print quality, color development, penetrability into paper, wettability, and leveling property.

[0055] <Other components> There are no particular restrictions on the other components contained in the non-aqueous clear ink, and they can be selected according to the purpose. Examples include defoamers, preservatives, rust preventives, pH adjusters, and the like.

[0056] - Defoamer - There are no particular restrictions on the defoaming agent. For example, silicone-based defoaming agents, polyether-based defoaming agents, fatty acid ester-based defoaming agents, etc. may be mentioned. These may be used alone or in combination of two or more. Among these, silicone-based defoaming agents are preferred in terms of excellent defoaming effect.

[0057] -Antiseptic and antifungal agent- There are no particular restrictions on the antiseptic and antifungal agent. For example, 1,2-benzisothiazolin-3-one, etc. may be mentioned.

[0058] -Rust inhibitor- There are no particular restrictions on the rust inhibitor. For example, acid sulfite, sodium thiosulfate, etc. may be mentioned.

[0059] -pH adjuster- There are no particular restrictions on the pH adjuster as long as it can adjust the pH to 7 or higher. For example, amines such as diethanolamine and triethanolamine may be mentioned.

[0060] There are no particular restrictions on the physical properties of the non-aqueous clear ink, and it can be appropriately selected according to the purpose. For example, it is preferable that the viscosity, surface tension, pH, etc. are in the following ranges.

[0061] There are no particular restrictions on the viscosity of the non-aqueous clear ink at 25°C, and it can be appropriately selected according to the purpose. However, from the points of improving the printing density and the quality of the characters and obtaining good discharge stability, it is preferably 5 mPa·s or more and 30 mPa·s or less, and more preferably 5 mPa·s or more and 25 mPa·s or less. As for the viscosity, for example, it can be measured under the measurement conditions of using a rotational viscometer (manufactured by Toki Sangyo Co., Ltd., RE-80L), at 25°C, with a standard cone rotor (1°34’×R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and for 3 minutes.

[0062] The surface tension of the non-aqueous clear ink at 25°C is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoints of favorable leveling of the ink on the recording medium and shortening of the drying time of the ink, 35 mN / m or less is preferable, and 32 mN / m or less is more preferable.

[0063] The pH of the non-aqueous clear ink is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoint of preventing corrosion of the metal members in contact with the liquid, 7 or more and 12 or less is preferable, and 8 or more and 11 or less is more preferable.

[0064] <Water-based ink> The water-based ink preferably contains a resin, an organic solvent, and water, and preferably contains a colorant and a surfactant, and further contains other components as necessary. The water-based ink has a resin content of 10% by mass or more. Thereby, the weather resistance and the abrasion resistance can be improved. The water-based ink contains an organic solvent having a boiling point of 240°C or higher, and the content of the organic solvent having a boiling point of 240°C or higher is 1% by mass or more and 3% by mass or less. When the content is 1% by mass or more, the weather resistance can be improved, and when the content is 3% by mass or less, the abrasion resistance can be improved.

[0065] <Resin> The resin is not particularly limited and can be appropriately selected according to the purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, acrylic silicone resin, etc. may be mentioned, and resin particles composed of these resins may also be used. Among these, polyurethane resin is preferable. It is possible to obtain an ink by mixing the resin particles with materials such as a colorant and an organic solvent in a state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those synthesized appropriately may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more kinds of resin particles.

[0066] The polyurethane resin is a reaction product of a polyisocyanate and a polyol, and exhibits the respective performances of a soft segment composed of a polyol component with weak cohesive force and a hard segment composed of a urethane bond with strong cohesive force. The soft segment is soft and resistant to deformation of the base material such as stretching and bending, and the hard segment has high adhesion to the base material and excellent abrasion resistance.

[0067] There is no particular limitation on the polyurethane resin, and it can be appropriately selected according to the purpose. Examples thereof include polyether-based urethane resins, polyester-based urethane resins, and polycarbonate-based urethane resins.

[0068] From the viewpoint of drying property, the content of the resin is 10% by mass or more, and more preferably 35% by mass or more and 40% by mass or less.

[0069] There is no particular limitation on the volume average particle diameter of the resin particles, and it can be appropriately selected according to the purpose. From the viewpoints of obtaining good fixing property and high image hardness, it 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 diameter can be measured, for example, using a particle size analyzer (NanoTrac Wave-UT151, manufactured by Microtrac Bell Corporation).

[0070] <Organic solvent> The organic solvent includes an organic solvent having a boiling point of 240°C or higher, and may include other organic solvents having a boiling point of less than 240°C as necessary. By including an organic solvent having a boiling point of 240°C or higher in the aqueous ink, sufficient fixing property to wallpaper and canvas fabric can be ensured, and drying near the nozzle can be suppressed to reduce ejection failure.

[0071] The organic solvent with a boiling point of 240 °C or higher is not particularly limited and can be appropriately selected according to the purpose. For example, glycerin (boiling point: 290 °C), diethylene glycol (boiling point: 244.8 °C), butyl carbitol acetate (boiling point: 246.8 °C to 247 °C), 2-ethyl-1,3-hexanediol (boiling point: 241 °C to 249 °C), ethylene glycol monophenyl ether (boiling point: 247 °C), 2-pyrrolidone (boiling point: 245 °C), etc. can be mentioned.

[0072] The content of the organic solvent with a boiling point of 240 °C or higher is 1% by mass or more and 3% by mass or less, and preferably 1.2% by mass or more and 2% by mass or less. When the content is 1% by mass or more, the weather resistance can be improved, and when the content is 3% by mass or less, the scratch resistance can be improved.

[0073] There are no particular restrictions on the other organic solvents, and water-soluble organic solvents can be used. For example, polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds can be mentioned. Specific examples of polyhydric alcohols include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-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, petriol, etc. Examples of polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, etc. Examples of nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, etc. Examples of amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, etc.Examples of the amines include monoethanolamine, diethanolamine, triethylamine, and the like. Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like. Examples of the other organic solvents include propylene carbonate, ethylene carbonate, and the like. It is preferable to use an organic solvent having a boiling point of 250°C or lower because it not only functions as a wetting agent but also provides good drying properties.

[0074] As the organic solvent, polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of the polyol compounds having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like. Specific examples of the glycol ether compounds include polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like; and polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, and the like. Regarding the composition of the organic solvent having 270°C or higher, 6% or more in the ink composition is preferable, and 10% or more is more preferable.

[0075] <Water> Regarding the content of the water, from the viewpoints of the drying property and ejection reliability of the ink, it is 1% by mass or more, and preferably 1% by mass or more and 10% by mass or less.

[0076] <Colorant> As the colorant, for example, pigments and dyes can be used.

[0077] As the pigment, an inorganic pigment or an organic pigment can be used. These can be used alone or in combination of two or more. Further, mixed crystals can be used as the pigment. As the pigment, for example, black pigment, yellow pigment, magenta pigment, cyan pigment, white pigment, green pigment, orange pigment, lustrous pigments such as gold and silver, and metallic pigments can be used. There is no particular limitation on the inorganic pigment, and it can be appropriately selected according to the purpose. For example, titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, carbon black produced by known methods, etc. can be mentioned. Examples of the known methods include methods such as the contact method, the furnace method, and the thermal method. There is no particular limitation on the organic pigment, and it can be appropriately selected according to the purpose. For example, azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye type chelates, acidic dye type chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be mentioned. Among these pigments, those with good affinity for the solvent are preferably used. In addition, the use of resin hollow particles and inorganic hollow particles is also possible.

[0078] Examples of the black pigments include carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, metals such as copper and iron (C.I. Pigment Black 11), titanium oxide, and organic pigments such as aniline black (C.I. Pigment Black 1). Further, examples of the color pigments include C.I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2 (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 (vermilion), 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, C.I. Pigment Violet 1 (rhodamine lake), 3, 5:1, 16, 19, 23, 38, C.I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15:1, 15:2, 15:3, 15:4 (phthalocyanine blue), 16, 17:1, 56, 60, 63, C.I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.

[0079] There are no particular restrictions on the dyes, and they can be appropriately selected according to the purpose. Examples include acid dyes, direct dyes, reactive dyes, and basic dyes. These may be used alone or in combination of two or more. Examples of the dye include C.I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. Acid Red 52, 80, 82, 249, 254, 289, C.I. Acid Blue 9, 45, 249, C.I. Acid Black 1, 2, 24, 94, C.I. Food Black 1, 2, C.I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. Direct Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. Reactive Red 14, 32, 55, 79, 249, C.I. Reactive Black 3, 4, 35.

[0080] The content of the colorant is not particularly limited and can be appropriately selected according to the purpose. From the viewpoints of good fixability and ejection stability, it is preferably 15% by mass or less, and more preferably 10% by mass or less.

[0081] Examples of the method for obtaining the ink by dispersing the pigment include a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersible pigment, a method of coating the surface of the pigment with a resin for dispersion, and a method of dispersing using a dispersant. Examples of the method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersible pigment include a method of making the pigment (e.g., carbon) dispersible in water by adding a functional group such as a sulfone group or a carboxyl group. Examples of the method of coating the surface of the pigment with a resin for dispersion include a method of incorporating the pigment into microcapsules to make it dispersible in water. This can be rephrased as resin-coated pigment. In this case, it is not necessary for all the pigments blended in the ink to be coated with the resin, and uncoated pigments or partially coated pigments may be dispersed in the ink as long as the effects of the present invention are not impaired. Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular dispersant or high-molecular dispersant typified by a surfactant. As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, etc. can be used according to the pigment. As the dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and sodium naphthalene sulfonate formalin condensate can also be preferably used as the dispersant. The dispersant may be used alone or in combination of two or more.

[0082] <Pigment dispersion> It is possible to obtain ink by mixing a pigment with materials such as water or an organic solvent. It is also possible to produce ink by mixing a pigment with other materials such as water or a dispersant to form a pigment dispersion and then mixing the pigment dispersion with materials such as water or an organic solvent. The pigment dispersion is obtained by dispersing water, a pigment, a pigment dispersant, and other components as necessary and adjusting the particle size. It is advisable to use a disperser for dispersion. Regarding the particle size of the pigment in the pigment dispersion, there is no particular limitation. However, from the viewpoints of good dispersion stability of the pigment and high image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number is preferably 20 nm or more and 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (NanoTrack Wave-UT151, manufactured by Microtrac Bell Corporation). The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoints of obtaining good ejection stability and increasing the image density, it is preferably 0.1% by mass or more and 50% by mass or less, and more preferably 0.1% by mass or more and 30% by mass or less. The pigment dispersion is preferably filtered to remove coarse particles and degassed using a filter, a centrifuge, etc. as necessary.

[0083] <Other components> The other components contained in the aqueous ink are not particularly limited and can be appropriately selected according to the purpose, and examples include surfactants, defoamers, antiseptic and antifungal agents, rust inhibitors, pH adjusters, etc. As the other components contained in the aqueous ink, the same components as those used in the non-aqueous clear ink can be used.

[0084] The physical properties of the aqueous ink are not particularly limited and can be appropriately selected according to the purpose. For example, it is preferable that the viscosity, surface tension, pH, etc. are within the following ranges.

[0085] The viscosity of the aqueous ink at 25°C is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoints of improving the printing density and character quality and obtaining good ejection stability, it is preferably 5 mPa·s or more and 30 mPa·s or less, and more preferably 6.5 mPa·s or more and 25 mPa·s or less. The viscosity of the aqueous ink at 40°C is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoints of improving the printing density and character quality and obtaining good ejection stability, it is preferably 6.5 mPa·s or more and 30 mPa·s or less. The viscosity can be measured, for example, using a rotational viscometer (manufactured by Toki Sangyo Co., Ltd., RE-80L) at 25°C under the measurement conditions of a standard cone rotor (1°34’×R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and for 3 minutes.

[0086] The surface tension of the aqueous ink at 25°C is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoints of the ink being preferably leveled on the recording medium and shortening the drying time of the ink, it is preferably 35 mN / m or less, and more preferably 32 mN / m or less.

[0087] The pH of the aqueous ink is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoint of preventing corrosion of the metal members in contact with the liquid, it is preferably 7 or more and 12 or less, and more preferably 8 or more and 11 or less.

[0088] <Object to be printed> The printed material is not limited to those used as a recording medium. For example, building materials such as wallpaper, floor materials, tiles, clothing fabrics such as T-shirts, textiles, leather, etc. can be appropriately used. By adjusting the configuration of the path for transporting the recording medium, ceramics, glass, metal, etc. can also be used as the printed material. There is no particular limitation on the recording medium, and ordinary paper, glossy paper, special paper, cloth, etc. can be used. However, good image formation is also possible using a non-permeable substrate. The non-permeable substrate is a substrate having a surface with low water permeability and absorbency, and includes materials that have a large number of cavities inside but do not open to the outside. More quantitatively, in the Bristow method, the water absorption from the start of contact to 30 msec 1 / 2 is 10 mL / m 2 or less, and this is what is meant by the substrate. As the non-permeable substrate, for example, plastic films such as vinyl chloride resin film, polyethylene terephthalate (PET) film, acrylic resin film, polypropylene film, polyethylene film, polycarbonate film, etc. can be preferably used.

[0089] In the present invention, in the low gloss printing mode, it is preferable to use a printed material with high gloss. A printed material with high gloss is preferable because the low gloss effect by the clear ink is more easily emphasized. On the other hand, in the high gloss printing mode, it is preferable to use a printed material with low gloss. A printed material with low gloss is preferable because the high gloss effect by the clear ink is more easily emphasized. Therefore, if the gloss of the printed material used in the low gloss printing mode is G matte and the gloss of the printed material used in the high gloss printing mode is G gloss , then the following formula, G matte >G gloss is preferably satisfied, and it is more preferable to satisfy G matte -G gloss ≧100.

[0090] (Method for Controlling Gloss of Printed Image) The method for controlling the gloss of a printed image according to the present invention includes the following steps: A printing process in which ink is ejected onto a substrate to form a printing layer; A heating step of heating the printed substrate; A method for controlling gloss of a printed image, comprising: the ink is a water-based clear ink containing a resin and water, The method for controlling the glossiness of a printed image includes a low gloss printing mode, which is a printing mode that imparts low gloss. a high gloss printing mode which is a printing mode that imparts high gloss, When printing in the low gloss printing mode, the heating temperature is controlled to be high, When printing in the high gloss printing mode, the heating temperature is controlled to be lowered.

[0091] (Printed material) The printed matter according to the present invention is a printed matter having a substrate and a printing layer on the substrate, the printing layer being made of a clear ink layer containing a resin, the printed matter has a low gloss (matte) print image printed in a low gloss (matte gloss) print mode and a high gloss (gloss) print image printed in a high gloss (gloss gloss) print mode, The gloss difference (Ga-Gb) between the 60° gloss Ga of the high-gloss (gloss) printed image and the 60° gloss Gb of the printed material used in the high-gloss (gloss) printing mode is 20 or more; An image can be formed to produce a printed matter using an inkjet printing device and inkjet printing method in which the gloss difference (Gc-Gd) between the 60° gloss Gc of the low gloss (matte gloss) printed image and the 60° gloss Gd of the printed material used in the low gloss (matte gloss) printing mode is -20 or less.

[0092] In the following description of the inkjet printing apparatus and inkjet printing method of the present invention, the use of black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink will be described; however, a water-based clear ink can be used instead of or in addition to these inks. The aqueous clear ink used in the present invention can be suitably used in various recording devices using an inkjet recording method, such as printers, facsimile machines, copying machines, printer / fax / copier multifunction machines, stereolithography devices, and the like. The inkjet printing device includes, unless otherwise particularly limited, both a serial type device that moves the ejection head and a line type device that does not move the ejection head. Furthermore, the inkjet printing device includes not only desktop type devices, but also wide-format recording devices, such as continuous printers that can use continuous paper wound in a roll as a recording medium. In the present invention, an inkjet printing device and an inkjet printing method are a device capable of ejecting ink and various processing liquids, etc. onto a recording medium, and a method of performing recording using the device. The recording medium means something to which ink and various processing liquids can adhere, even temporarily. The inkjet printing device can include not only the head portion that ejects ink, but also means related to feeding, transporting, and discharging the recording medium, and other devices referred to as pre-processing devices and post-processing devices. Also, the inkjet printing device and the inkjet printing recording method are not limited to those in which significant images such as characters and figures are visualized by ink. For example, those that form patterns such as geometric patterns, and those that create three-dimensional images are also included. Also, the inkjet printing device includes, unless otherwise particularly limited, both a serial type device that moves the ejection head and a line type device that does not move the ejection head. Furthermore, the inkjet printing device includes not only desktop type devices, but also wide-format recording devices capable of printing on A0 size recording media, such as continuous printers that can use continuous paper wound in a roll as a recording medium.

[0093] An example of the inkjet printing device will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective explanatory view of the inkjet printing apparatus. FIG. 2 is a perspective explanatory view of the main tank. An image forming apparatus 400 as an example of the inkjet printing apparatus is a serial type image forming apparatus. A mechanism unit 420 is provided inside an exterior 401 of the image forming apparatus 400. Each ink storage unit 411 of main tanks 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is formed of a packaging member such as an aluminum laminate film, for example. The ink storage unit 411 is stored in a storage container case 414 made of plastics, for example. Thereby, the main tank 410 is used as an ink cartridge for each color. On the other hand, a cartridge holder 404 is provided on the back side of the opening when the cover 401c of the apparatus main body is opened. The main tank 410 is detachably attached to the cartridge holder 404. Thereby, each ink discharge port 413 of the main tank 410 and a discharge head 434 for each color communicate with each other via a supply tube 436 for each color, and ink can be discharged from the discharge head 434 onto a recording medium.

[0094] The inkjet printing apparatus can include not only a portion that discharges ink but also apparatuses referred to as a preprocessing apparatus and a postprocessing apparatus. As an aspect of the preprocessing apparatus and the postprocessing apparatus, in the same manner as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), a liquid storage unit having a preprocessing liquid and a postprocessing liquid and a liquid discharge head are added, and there is an aspect of discharging the preprocessing liquid and the postprocessing liquid by an inkjet recording method. As another aspect of the preprocessing apparatus and the postprocessing apparatus, there is an aspect of providing a preprocessing apparatus and a postprocessing apparatus by a method other than the inkjet recording method, for example, a blade coating method, a roll coating method, or a spray coating method.

[0095] Note that the method of using the ink is not limited to the inkjet recording method and can be widely used. In addition to the inkjet recording method, for example, blade coating method, gravure coating method, bar coating method, roll coating method, dip coating method, curtain coating method, slide coating method, die coating method, spray coating method, etc. can be mentioned.

[0096] The use of the ink is not particularly limited and can be appropriately selected according to the purpose. For example, it can be applied to printed matter, paints, coating materials, substrates, etc. Furthermore, not only can it be used as an ink to form two-dimensional characters and images, but it can also be used as a material for three-dimensional modeling to form three-dimensional solid images (three-dimensional modeled objects). As the three-dimensional modeling apparatus for modeling a three-dimensional modeled object, a known one can be used and is not particularly limited. For example, one equipped with an ink storage means, supply means, discharge means, drying means, etc. can be used. The three-dimensional modeled object includes a three-dimensional modeled object obtained by, for example, overcoating the ink. In addition, it also includes a molded processed product obtained by processing a structure in which ink is applied on a base material such as a recording medium. The molded processed product is, for example, a recording object and a structure formed in a sheet shape or a film shape, which are subjected to molding processes such as heat stretching and punching, and are suitably used for applications such as forming the surface after decoration for meters, operation panel of OA equipment, electric and electronic equipment, cameras, etc. of automobiles.

[0097] Also, in the terms of the present invention, image formation, recording, printing, etc. are all regarded as synonyms. Recording medium, medium, object to be printed are all regarded as synonyms.

Examples

[0098] Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples at all.

[0099] (Production Example 1) -Production of non-aqueous clear ink A- 19.5% by mass of a commercially available urethane resin solution (Sample IB-F370, manufactured by Sanyo Chemical Industries, Ltd., non-volatile content: 40% by mass, non-aqueous system, solvent: mixed solvent of methoxypropanol and isopropanol), 55% by mass of diethylene glycol diethyl ether, 13.1% by mass of γ-butyrolactone, 10% by mass of tetraethylene glycol dimethyl ether, 0.6% by mass of a silicone-based surfactant (BYK-UV3500, manufactured by BYK), and 1.8% by mass of an acetylene glycol-based surfactant (E-1010, manufactured by Nissin Chemical Industry Co., Ltd.) were added and mixed and stirred to prepare a mixture. Next, the obtained mixture was filtered through a polypropylene filter with an average pore size of 0.2 μm (trade name: Betafine polypropylene pleated filter PPG series, manufactured by 3M) to produce a non-aqueous clear ink A.

[0100] (Production Examples 2 to 3) -Production of Non-aqueous Clear Inks B to C- In Production Example 1, non-aqueous clear inks B to C were produced in the same manner as in Production Example 1, except that the ink compositions shown in Table 1 were changed.

[0101]

Table 1

[0102] Details of each component in Table 1 above are as follows. ·Urethane resin solution (Sample IB-F370, manufactured by Sanyo Chemical Industries, Ltd., non-volatile content: 40% by mass, non-aqueous system, solvent: mixed solvent of methoxypropanol and isopropanol) ·Acrylic resin solution (N-2043-60MEX, manufactured by Harima Chemicals, Inc., non-volatile content: 60% by mass) ·Silicone-based surfactant (BYK-UV3500, manufactured by BYK) ·Acetylene glycol-based surfactant (E-1010, manufactured by Nissin Chemical Industry Co., Ltd.)

[0103] (Preparation Example 1) -Preparation of Urethane Resin Emulsion A- In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 200.4 g of a polyester polyol (trade name: PolyLite OD-X-2251, manufactured by DIC Corporation, average molecular weight 2,000) in a double amount, 15.7 g of 2,2-dimethylolpropionic acid, 48.0 g of isophorone diisocyanate, and 77.1 g of methyl ethyl ketone as an organic solvent were reacted using 0.06 g of DMTDL (dibutyltin dilaurate) as a catalyst. After continuing the reaction for 4 hours, 30.7 g of methyl ethyl ketone was supplied as a diluting solvent, and the reaction was further continued. When the average molecular weight of the reaction product reached the 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. Next, 13.4 g of a 48% by mass aqueous potassium hydroxide solution was added to the organic solvent solution of the urethane resin to neutralize the carboxyl groups possessed by the urethane resin. Then, 715.3 g of water was added and stirred well. After that, by aging and desolventizing, a urethane resin emulsion A was obtained. Regarding the obtained urethane resin emulsion A, the minimum film-forming temperature (MFT) measured with a film-forming temperature test apparatus (manufactured by Imoto Seisakusho Co., Ltd.) was 74 °C.

[0104] (Preparation Example 2) - Preparation of Urethane Resin Emulsion B - Into a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, 1,500 g of a polycarbonate diol (reaction product of 1,6-hexanediol and dimethyl carbonate (number average molecular weight (Mn): 1,200)), 220 g of 2,2-dimethylolpropionic acid (hereinafter sometimes referred to as "DMPA"), and 1,347 g of N-methylpyrrolidone (hereinafter sometimes referred to as "NMP") were charged under a nitrogen stream and heated to 60 °C to dissolve DMPA. Next, 1,445 g of 4,4'-dicyclohexylmethane diisocyanate and 2.6 g of dibutyltin dilaurate (catalyst) were added and heated to 90 °C, and a urethanization reaction was carried out over 5 hours to obtain an isocyanate-terminated urethane prepolymer. The obtained isocyanate-terminated urethane prepolymer was cooled to 80 °C, 149 g of triethylamine was added and mixed, and 4,340 g was withdrawn from the mixture and added to a mixed solution of 5,400 g of water and 15 g of triethylamine under strong stirring. Next, 1,500 g of ice was charged, 626 g of a 35 mass% aqueous solution of 2-methyl-1,5-pentanediamine was added, and a chain extension reaction was carried out to obtain urethane resin emulsion B. Regarding the obtained urethane resin emulsion B, when measured with a film-forming temperature test apparatus (manufactured by Imoto Seisakusho Co., Ltd.), the minimum film-forming temperature was 55 °C.

[0105] (Preparation Example 3) - Preparation of acrylic resin emulsion A - After thoroughly replacing the inside of a 1 L flask equipped with a mechanical stirrer, a thermometer, a nitrogen gas introduction tube, a reflux tube, and a dropping funnel with nitrogen gas, 17.5 g of Latemul S-180 and 350 g of ion-exchanged water were added and mixed, and the temperature was raised to 65 °C. After the temperature rise, 3.0 g of t-butyl peroxybenzoate, which is a reaction initiator, and 1.0 g of sodium isoascorbate were added. After 5 minutes, 45 g of methyl methacrylate, 160 g of 2-ethylhexyl methacrylate, 5 g of acrylic acid, 45 g of butyl methacrylate, 30 g of cyclohexyl methacrylate, 15 g of vinyltriethoxysilane, 8.0 g of Latemul S-180, and 340 g of ion-exchanged water were mixed and added dropwise over 3 hours. Then, after heating and aging at 80 °C for 2 hours, it was cooled to room temperature, and the pH was adjusted to 7 - 8 with sodium hydroxide. Ethanol was distilled off using an evaporator, and the water content was adjusted to prepare an acrylic resin emulsion A with a solid content of 40 mass%. Regarding the obtained acrylic resin emulsion A, the minimum film-forming temperature (MFT) measured with a film-forming temperature test apparatus (manufactured by Imoto Seisakusho Co., Ltd.) was 95 °C.

[0106] (Preparation Example 4) - Preparation of acrylic resin emulsion B - To a reaction vessel equipped with a stirrer, a reflux condenser, a dropping device, and a thermometer, 900 parts by mass of ion-exchanged water and 1 part by mass of sodium lauryl sulfate were added, and the temperature was raised to 70 °C while purging with nitrogen under stirring. While maintaining the temperature in the reaction vessel at 70 °C, 4 parts by mass of potassium persulfate as a polymerization initiator was added and dissolved. After dissolution, an emulsion prepared by adding 450 parts by mass of ion-exchanged water, 3 parts by mass of sodium lauryl sulfate, 20 parts by mass of acrylamide, 365 parts by mass of styrene, 545 parts by mass of butyl acrylate, and 10 parts by mass of methacrylic acid under stirring was continuously added dropwise to the reaction solution over 4 hours. After completion of the dropping, it was held for 3 hours, and the obtained aqueous emulsion was cooled to room temperature. Then, ion-exchanged water and an aqueous sodium hydroxide solution were added to adjust the pH to 8, and an acrylic resin emulsion B with a solid content of 30% by mass was obtained. Regarding the obtained acrylic resin emulsion B, the minimum film-forming temperature (MFT) measured with a film-forming temperature test apparatus (manufactured by Imoto Seisakusho Co., Ltd.) was 85 °C.

[0107] (Production Example 4) - Production of Aqueous Ink A (Black Ink A)- After premixing 3 parts by mass of a black pigment (carbon black), 0.5 part by mass of a dispersant (Pionin A-51-B, manufactured by Takemoto Yushi Co., Ltd.), and 58.5 parts by mass of diethylene glycol diethyl ether, it was circulated and dispersed with a disk-type bead mill (manufactured by Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls with a diameter of 0.3 mm) for 3 hours to obtain a black pigment dispersion.

[0108] Next, 18.7 parts by mass of the obtained black pigment dispersion, 17.1 parts by mass of the urethane resin emulsion A, 20.6 parts by mass of the urethane resin emulsion B, 0.3 parts by mass of 2-amino-2-ethyl-1,3-propanediol (AEPD) (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.2 parts by mass of glycerin, 29.0 parts by volume of isoprene glycol, 0.8 parts by mass of a silicone-based surfactant KF-643 (Shin-Etsu Chemical Co., Ltd.), 0.2 parts by mass of an antifoaming agent Surfynol AD01 (manufactured by Nissin Chemical Industry Co., Ltd.) were added, and deionized water was added to make the total 100 parts by mass, and the mixture was stirred to prepare a mixture. The obtained mixture was filtered through a polypropylene filter (trade name: Betafine polypropylene pleated filter PPG series, manufactured by 3M) with an average pore diameter of 0.2 μm to produce an aqueous ink A (black ink A).

[0109] (Production Examples 5 to 10) -Production of Aqueous Inks B to G (Black Inks B to G)- In Production Example 4, except that the composition shown in Tables 2 and 3 was changed, aqueous inks B to G (black inks B to G) were produced in the same manner as in Production Example 4.

[0110]

Table 2

[0111]

Table 3

[0112] (Example 1) The ink cartridge of an inkjet printer GXe5500 conversion machine (manufactured by Ricoh Company, Ltd.) was filled with the non-aqueous clear ink A of Production Example 1 and the aqueous ink A (black ink A) of Production Example 4. The ink cartridge filled with the ink was installed in the inkjet printer GXe5500 conversion machine, and inkjet printing was carried out using the aqueous ink A (black ink A). Subsequently, inkjet printing was performed using the non-aqueous clear ink A. A heater (temperature control controller, model MTCD, manufactured by Misumi Corporation) was provided in the modified inkjet printer GXe5500 so that the recording medium could be heated from the back surface before, during, and after printing. As a result, printing can be performed on the recording medium heated by the heater before and during printing, and the printed matter can be heated and dried by the heater after printing. Printing was performed by changing the type of recording medium, heating conditions, and printed image in the high gloss (glossy) printing mode and the low gloss (matte) printing mode.

[0113] -Recording Medium- In the high gloss (glossy) printing mode, as the recording medium 1, synthetic paper VJFN160 (white polypropylene film, glossiness 16 (60° gloss value)) manufactured by Upo Corporation was used. In the low gloss (matte) printing mode, as the recording medium 2, window film GIY-0305 (transparent polyethylene terephthalate (PET) film, glossiness 159 (60° gloss value)) manufactured by Lintec Sign Systems Co., Ltd. was used.

[0114] -Color Printing Conditions- In color printing, the heating temperatures of each heater (heating means) arranged before, during, and after printing were set to 45°C, 45°C, and 60°C, and a solid-color image with an image resolution of 600 dpi × 600 dpi and a printing rate of 100% was printed.

[0115] -Heating Conditions of Non-Aqueous Clear Ink- As the heating conditions of the non-aqueous clear ink, in the high gloss (glossy) printing mode, the heating temperatures of each heater (heating means) arranged before, during, and after printing were set to 45°C, 45°C, and 60°C, and in the low gloss (matte) printing mode, the heating temperatures of each heater (heating means) arranged before, during, and after printing were set to 65°C, 65°C, and 70°C. When measuring the temperature of the recording medium during printing, the recording medium temperature (T in the high gloss (glossy) printing mode gloss) is 45°C, which is the temperature (HT gloss ) of the heating means in the high-gloss (glossy) printing mode during printing. matte ) is 64°C. Also, when measuring the temperature of the recording medium during printing, the temperature of the recording medium (T matte ) in the low-gloss printing mode is 64°C, and the temperature (HT ) of the heating means in the low-gloss printing mode during printing is 65°C.

[0116] -Printing rate- Note that the printing rate here means the following. Printing rate (%) = Number of clear ink printed dots / (Vertical resolution × Horizontal resolution) × 100 (However, in the above formula, the "number of clear ink printed dots" is the number of dots where clear ink is actually printed per unit area, and the "vertical resolution" and "horizontal resolution" are the resolutions per unit area respectively. When clear ink is printed in layers so that the same dot positions overlap, the "number of clear ink printed dots" is represented by the total number of dots where clear ink is actually printed per unit area.) The non-aqueous clear ink A was printed on the recording medium by directly applying it once in an overlapping manner at the same dot positions. Next, for the obtained printed matter, the glossiness, abrasion resistance, weather resistance, and drying property were measured as follows. The results are shown in Table 4.

[0117] <Glossiness> The 60° gloss values of both the clear ink printed part where the non-aqueous clear ink A was printed and the clear ink non-printed part (recording medium) where the non-aqueous clear ink A was not printed were measured using a glossiness measuring device (Microtri Gloss, manufactured by BYK). Note that the 60° gloss value was used as the glossiness. (Evaluation method) The glossiness difference between the clear ink printed part and the clear ink non-printed part (recording medium) was evaluated according to the following criteria. 〇 indicates a practical range. (Evaluation criteria) ○: Gloss difference of 20 or more ×: Gloss difference of less than 20

[0118] <Scratch resistance> An aqueous ink (black ink) and a non-aqueous clear ink were printed on the surface of the printed material to form an image. After leaving it for one hour, a gold bar was rubbed on the formed image using a Kagaku Shinkou testing machine, and the image density (OD) transferred to the gold bar was measured using xRite (manufactured by PANTONE) to evaluate the weather resistance. The printing conditions were 600×600 dpi, the load was 200 gf, and the number of rubbing times was 25. According to the following evaluation criteria, Δ or more is within the practical range, and ○ is preferable. (Evaluation criteria) ○: Less than 0.15 Δ: 0.15 or more and less than 0.28 ×: 0.28 or more

[0119] <Weather resistance> An aqueous ink (black ink) and a non-aqueous clear ink were printed on the surface of the printed material to form an image. The formed image was placed in a weather meter (SX75), and exposed under the conditions of an output of 180 W / m 2 , a total received light amount of 324 MJ / m 2 , and an exposure time of 500 hours. The image density (OD) was measured before and after exposure, and the OD change was evaluated according to the following criteria. ○ is within the practical range. (Evaluation criteria) ○: Less than 0.1 ×: 0.1 or more

[0120] <Drying property> An aqueous ink (black ink) and a non-aqueous clear ink were printed on the surface of the printed material to form an image. Every 30 seconds after image formation, a printed material identical to the non-permeable printed material cut into a 2 cm square was pressed against the surface of the ink coating film. The pressing load was 103 g / cm 2 , and the pressing time was 10 seconds. The printed material was peeled off from the ink coating film, and the time taken until the transfer and peeling of the ink coating film in the previous period disappeared was measured and evaluated according to the following criteria. According to the following evaluation criteria, Δ or more is within the practical range, and ○ is preferable. (Evaluation criteria) ○: Less than 7 points △: 7 points or more and less than 9 points ×: 9 points or more

[0121] (Example 2) In Example 1, inkjet printing was performed in the same manner as in Example 1, except that the non-aqueous clear ink A was changed to non-aqueous clear ink B. For the obtained printed matter, the glossiness, rub resistance, weather resistance, and drying property were measured in the same manner as in Example 1. The results are shown in Table 4.

[0122] (Example 3) In Example 1, inkjet printing was performed in the same manner as in Example 1, except that the non-aqueous clear ink A was changed to non-aqueous clear ink C, and the aqueous ink A (black ink A) was changed to aqueous ink B (black ink B). For the obtained printed matter, the glossiness, rub resistance, weather resistance, and drying property were measured in the same manner as in Example 1. The results are shown in Table 4.

[0123] (Example 4) In Example 1, inkjet printing was performed in the same manner as in Example 1, except that the aqueous ink A (black ink A) was changed to aqueous ink D (black ink D). For the obtained printed matter, the glossiness, rub resistance, weather resistance, and drying property were measured in the same manner as in Example 1. The results are shown in Table 4.

[0124] (Example 5) In Example 1, inkjet printing was performed in the same manner as in Example 1, except that the aqueous ink A (black ink A) was changed to aqueous ink E (black ink E). For the obtained printed matter, the glossiness, rub resistance, weather resistance, and drying property were measured in the same manner as in Example 1. The results are shown in Table 4.

[0125] (Comparative Example 1) In Example 1, inkjet printing was performed in the same manner as in Example 1, except that the aqueous ink A (black ink A) was changed to the aqueous ink C (black ink C). For the obtained printed matter, the glossiness, rubbing resistance, weather resistance, and drying property were measured in the same manner as in Example 1. The results are shown in Table 5.

[0126] (Comparative Example 2) In Example 1, inkjet printing was performed in the same manner as in Example 1, except that the non-aqueous clear ink was not used. For the obtained printed matter, the glossiness, rubbing resistance, weather resistance, and drying property were measured in the same manner as in Example 1. The results are shown in Table 5.

[0127] (Comparative Example 3) In Example 1, inkjet printing was performed in the same manner as in Example 1, except that the aqueous ink A (black ink A) was changed to the aqueous ink F (black ink F). For the obtained printed matter, the glossiness, rubbing resistance, weather resistance, and drying property were measured in the same manner as in Example 1. The results are shown in Table 5.

[0128] (Comparative Example 4) In Example 1, inkjet printing was performed in the same manner as in Example 1, except that the aqueous ink A (black ink A) was changed to the aqueous ink G (black ink G). For the obtained printed matter, the glossiness, rubbing resistance, weather resistance, and drying property were measured in the same manner as in Example 1. The results are shown in Table 5.

[0129] [Table 4]

[0130] [Table 5]

[0131] As a result of comparing Example 1 and Comparative Example 2 in Tables 4 and 5, it was confirmed that the combination of the non-aqueous clear ink and the aqueous ink improved the gloss rate, rubbing resistance, weather resistance, and drying property. As a result of comparing Example 1 and Example 2 in Table 4, it was confirmed that the drying property was improved when the content of the resin in the non-aqueous clear ink was smaller. As a result of comparing Example 1 and Example 3 in Table 4, it was confirmed that Example 1 was improved in terms of rubbing resistance. As a result of comparing Example 1 and Comparative Example 1 in Tables 4 and 5, it was confirmed that when the content of glycerin having a boiling point of 240 ° C or higher was 3% by mass or less, the glossiness, rubbing resistance, and drying property were improved.

[0132] As aspects of the present invention, for example, they are as follows. <1> An ink containing portion for containing ink, A discharge head for discharging ink, Heating means for heating a printing object, An inkjet printing apparatus having: The inkjet printing apparatus has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss. When the heating means prints in a low gloss printing mode when attaching the non-aqueous clear ink to the printing object, the temperature of the printing object in the low gloss printing area is T matte (° C), and when the non-aqueous clear ink is attached to the printing object, the temperature of the printing object in the high gloss printing area printed in the high gloss printing mode is T gloss (° C), then the following formula, T matte > T gloss , and heating is performed so as to satisfy: The ink has a non-aqueous clear ink containing a resin and an organic solvent, and an aqueous ink containing a resin, an organic solvent, and water. The content of the resin contained in the aqueous ink is 10% by mass or more. The inkjet printing apparatus is characterized in that the organic solvent contained in the aqueous ink contains an organic solvent having a boiling point of 240 °C or higher, and the content of the organic solvent having a boiling point of 240 °C or higher is 1% by mass or more and 3% by mass or less. <2> The heating means heats so as to satisfy the following formula: T matte -T gloss ≧10 °C, which is the inkjet printing apparatus according to <1> above. <3> An inkjet printing apparatus having an ink storage section for storing ink, a discharge head for discharging ink, and heating means for heating a printing object, wherein the inkjet printing apparatus has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss, wherein the temperature of the heating means in the low gloss printing mode is HT (°C), and the temperature of the heating means in the high gloss printing mode is HT matte (°C), then, according to the following formula: HT gloss (°C), it heats so as to satisfy the following formula: HT matte >HT gloss (°C), wherein the ink has a non-aqueous clear ink containing a resin and an organic solvent, and an aqueous ink containing a resin, an organic solvent, and water, wherein the content of the resin contained in the aqueous ink is 10% by mass or more, The inkjet printing apparatus is characterized in that the organic solvent contained in the aqueous ink contains an organic solvent having a boiling point of 240 °C or higher, and the content of the organic solvent having a boiling point of 240 °C or higher is 1% by mass or more and 3% by mass or less. <4> The glossiness of the printing object used in the low gloss printing mode is G matte and the glossiness of the printing object used in the high gloss printing mode is G gloss , then, according to the following formula: G matte >G gloss (°C), which is the inkjet printing apparatus according to any one of <1> to <3> above. <5> The inkjet printing apparatus according to any one of <1> to <4> above, wherein the organic solvent contained in the non-aqueous clear ink is at least one selected from an alkylene glycol diether compound, an alkylene glycol monoether compound, and a lactone compound. <6> The inkjet printing apparatus according to any one of <1> to <5> above, wherein the resin content in the non-aqueous clear ink is 9% by mass or more. <7> The inkjet printing apparatus according to <6> above, wherein the resin content in the non-aqueous clear ink is 9% by mass or more and 20% by mass or less. <8> The inkjet printing apparatus according to any one of <1> to <7> above, wherein the non-aqueous clear ink further contains a surfactant, and the surfactant content is 2% by mass or more. <9> The inkjet printing apparatus according to any one of <1> to <8> above, wherein the viscosity of the aqueous ink at 40 °C is 6.5 mPa·s or more. <10> The inkjet printing apparatus according to any one of <1> to <9> above, wherein the organic solvent contained in the aqueous ink contains an organic solvent having a boiling point of 270 °C or higher, and the content of the organic solvent having a boiling point of 270 °C or higher is 1% by mass or more and 3% by mass or less. <11> A step of applying an aqueous ink containing 10% by mass or more of resin, 1% by mass or more and 3% by mass or less of an organic solvent having a boiling point of 240 °C or higher, and water to a printing object to print an image; A step of applying a non-aqueous clear ink containing a resin and an organic solvent to a printing object; A heating step of heating the printing object by heating means, and having A low gloss printing mode that is a printing mode for imparting low gloss and a high gloss printing mode that is a printing mode for imparting high gloss, In the heating step, the temperature of the printing object in the low gloss printing area printed in the low gloss printing mode when the non-aqueous clear ink is adhered to the printing object is T matte (°C), and the temperature of the printing object in the high gloss printing area printed in the high gloss printing mode when the non-aqueous clear ink is adhered to the printing object is Tgloss When it is T matte >T gloss It is an inkjet printing method that heats so as to satisfy. <12> A step of applying an aqueous ink containing 10% by mass or more of a resin, 1% by mass or more and 3% by mass or less of an organic solvent having a boiling point of 240 ° C or higher, and water to a printing object to form a printing layer; A step of applying a non-aqueous clear ink containing a resin and an organic solvent to a printing object; A heating step of heating the printing object by heating means, and It has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss. In the heating step, the temperature of the heating means in the low gloss printing mode when the non-aqueous clear ink is adhered to the printing object is HT matte (° C), and the temperature of the heating means in the high gloss printing mode is HT gloss (° C), then the following formula, HT matte > HT gloss It is an inkjet printing method that heats so as to satisfy.

[0133] According to the inkjet printing apparatus according to any one of <1> to <10> and the inkjet printing method according to any one of <11> to <12>, various conventional problems can be solved and the object of the present invention can be achieved.

Explanation of symbols

[0134] 400 Image forming apparatus 401 Exterior 401c Cover 404 Cartridge holder 410, 410k, 410c, 410m, 410y Main tank 411 Ink storage section 413 Ink discharge port 414 Storage container case 420 Mechanism section 434 Discharge head 436 Supply tube L Ink Storage Container

Prior Art Documents

Patent Documents

[0135]

Patent Document 1

Claims

1. An inkjet printing apparatus comprising an ink storage section for storing ink, a discharge head for discharging ink, heating means for heating a printing medium, wherein the inkjet printing apparatus has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss, the ink includes a non-aqueous clear ink containing a resin and an organic solvent, and an aqueous ink containing a resin, an organic solvent, and water, Let the temperature of the object to be printed in the low gloss printing area, where the heating means prints in the low gloss printing mode when attaching the non-aqueous clear ink to the object to be printed, be T ｍａｔｔｅ (°C), and let the temperature of the object to be printed in the high gloss printing area, where the heating means prints in the high gloss printing mode when attaching the non-aqueous clear ink to the object to be printed, be T ｇｌｏｓｓ (°C). Then, for the following formula, T ｍａｔｔｅ > T ｇｌｏｓｓ , heat so as to satisfy it, the content of the resin contained in the aqueous ink is 10% by mass or more, the organic solvent contained in the aqueous ink includes an organic solvent having a boiling point of 240°C or higher, and the content of the organic solvent having a boiling point of 240°C or higher is 1% by mass or more and 3% by mass or less. An inkjet printing apparatus characterized by the above.

2. wherein the heating means heats so as to satisfy the following formula: T ｍａｔｔｅ − T ｇｌｏｓｓ ≧ 10°C, the inkjet printing apparatus according to claim 1.

3. An inkjet printing apparatus comprising an ink storage section for storing ink, a discharge head for discharging ink, heating means for heating a printing medium, wherein the inkjet printing apparatus has a low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss, the ink includes a non-aqueous clear ink containing a resin and an organic solvent, and an aqueous ink containing a resin, an organic solvent, and water, Let the temperature of the heating means in the low gloss printing mode be HT ｍａｔｔｅ (°C), and let the temperature of the heating means in the high gloss printing mode be HT ｇｌｏｓｓ (°C). Then, for the following formula, HT ｍａｔｔｅ > HT ｇｌｏｓｓ , heat so as to satisfy it, the content of the resin contained in the aqueous ink is 10% by mass or more, the organic solvent contained in the aqueous ink includes an organic solvent having a boiling point of 240°C or higher, and the content of the organic solvent having a boiling point of 240°C or higher is 1% by mass or more and 3% by mass or less. An inkjet printing apparatus characterized by the above.

4. Let the glossiness of the object to be printed used in the low gloss printing mode be G ｍａｔｔｅ and let the glossiness of the object to be printed used in the high gloss printing mode be G ｇｌｏｓｓ Then, the following formula, G ｍａｔｔｅ > G ｇｌｏｓｓ is satisfied. The inkjet printing apparatus according to any one of claims 1 to 3.

5. The inkjet printing apparatus according to any one of Claims 1 to 4, wherein the organic solvent contained in the non-aqueous clear ink is at least one selected from an alkylene glycol diether compound, an alkylene glycol monoether compound, and a lactone compound.

6. The inkjet printing apparatus according to any one of Claims 1 to 5, wherein the content of the resin contained in the non-aqueous clear ink is 9% by mass or more.

7. The inkjet printing apparatus according to any one of Claims 1 to 6, wherein the non-aqueous clear ink further contains a surfactant, and the content of the surfactant is 2% by mass or more.

8. The inkjet printing apparatus according to any one of Claims 1 to 7, wherein the viscosity of the aqueous ink at 40°C is 6.5 mPa·s or more and 30 mPa·s or less.

9. A step of applying an aqueous ink containing 10% by mass or more of a resin, 1% by mass or more and 3% by mass or less of an organic solvent having a boiling point of 240°C or higher, and water to a printing substrate to form a printed layer; A step of applying a non-aqueous clear ink containing a resin and an organic solvent to the printing substrate; A heating step of heating the printing substrate by heating means, and having A low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss; In the heating step, the temperature of the object to be printed in the low gloss printing area printed in the low gloss printing mode when the non-aqueous clear ink is attached to the object to be printed is T ｍａｔｔｅ (°C), and the temperature of the object to be printed in the high gloss printing area printed in the high gloss printing mode when the non-aqueous clear ink is attached to the object to be printed is T ｇｌｏｓｓ (°C). Then, an inkjet printing method of heating so as to satisfy the following formula: T ｍａｔｔｅ > T ｇｌｏｓｓ .

10. A step of applying an aqueous ink containing 10% by mass or more of a resin, 1% by mass or more and 3% by mass or less of an organic solvent having a boiling point of 240°C or higher, and water to a printing substrate to form a printed layer; A step of applying a non-aqueous clear ink containing a resin and an organic solvent to the printing substrate; A heating step of heating the printing substrate by heating means, and having A low gloss printing mode which is a printing mode for imparting low gloss and a high gloss printing mode which is a printing mode for imparting high gloss; In the heating step, the temperature of the heating means in the low gloss printing mode when the non-aqueous clear ink is attached to the object to be printed is HT ｍａｔｔｅ (°C), and the temperature of the heating means in the high gloss printing mode is HT ｇｌｏｓｓ (°C). Then, an inkjet printing method of heating so as to satisfy the following formula: HT ｍａｔｔｅ > HT ｇｌｏｓｓ .

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