Image recording method

Abstract

Provided is an image recording method which includes: a step for applying a pretreatment liquid containing water and a flocculant onto a recording medium; and a step for applying, using an inkjet method, an ink containing water and a pigment onto a region of the recording medium to which the pretreatment liquid has been applied. At least the pretreatment liquid contains an additive (A) that is at least one type selected from the group consisting of a photostabilizer and an ultraviolet radiation absorber. The total amount of the additive (A) applied onto the recording medium is 0.05 g / m2 to 2.00 g / m2. The ratio of the amount of the additive (A) applied through application of the pretreatment liquid relative to the total amount of the additive (A) applied onto the recording medium is 50 mass% to 100 mass%.

Description

Image recording method

[0001] The present disclosure relates to an image recording method.

[0002] Various studies have been conducted on image recording in which ink is applied by an inkjet method (i.e., inkjet recording). For example, Patent Documents 1 to 6 describe adding a light stabilizer or an ultraviolet absorber to ink used in inkjet methods in order to improve the light resistance of the recorded image. Furthermore, Patent Documents 7 and 8 disclose image recording methods in which, in order to improve the image quality of the recorded image, a pretreatment liquid containing a flocculant is applied onto a recording medium, and then ink is applied by inkjet to the area of ​​the recording medium to which the pretreatment liquid has been applied.

[0003] Patent Document 1: JP-A-10-279854 Patent Document 2: JP-A-10-279859 Patent Document 3: JP-A-10-279860 Patent Document 4: JP-A-11-12519 Patent Document 5: JP-A-2002-179963 Patent Document 6: JP-A-2002-79739 Patent Document 7: JP-A-2004-276253

[0004] However, through investigations by the present inventors, it has been found that when an attempt is made to improve the lightfastness of an image recorded using a pretreatment liquid and ink, at least one of the color density and image quality of the image may decrease, and furthermore, when an attempt is made to ensure the color density and image quality of the image, the effect of improving the lightfastness may decrease.

[0005] An object of one aspect of the present disclosure is to provide an image recording method capable of recording an image excellent in light resistance, color density, and image quality.

[0006] The present disclosure includes the following aspects: <1> A method for producing a recording medium, comprising: applying a pretreatment liquid containing water and a flocculant onto a recording medium; and applying, by an inkjet method, an ink containing water and a pigment onto the area of ​​the recording medium to which the pretreatment liquid has been applied, wherein at least the pretreatment liquid contains an additive (A) that is at least one selected from the group consisting of a light stabilizer and an ultraviolet absorber, and wherein the total amount of the additive (A) applied onto the recording medium is 0.05 g / m ２ ~2.00g / m ２ and the proportion of the amount of additive (A) applied by applying the pretreatment liquid to the total amount of additive (A) applied is 50% by mass to 100% by mass.

[0007] <2> The image recording method according to <1>, wherein the light stabilizer includes a hindered amine compound (I) having a structure represented by the following formula (I):

[0008]

[0009] In formula (I), R １ represents a hydrogen atom, a hydroxy group, an alkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, or an acyloxy group having 1 to 40 carbon atoms; R ２ ~R ５ each independently represents an alkyl group having 1 to 5 carbon atoms, and two * each represent a bonding position. ２ and R ３ , and R ４ and R ５ may be linked via an oxygen atom, a nitrogen atom, or a sulfur atom, or may be linked directly to form a ring.

[0010] <3> The image recording method according to <1> or <2>, wherein the UV absorber comprises at least one selected from the group consisting of benzotriazole compounds and triazine compounds. <4> The image recording method according to any one of <1> to <3>, wherein the coagulant comprises at least one selected from the group consisting of organic acids and organic acid salts. <5> The image recording method according to any one of <1> to <4>, wherein the ink further comprises an additive (A) that is at least one selected from the group consisting of a light stabilizer and a UV absorber. <6> The image recording method according to any one of <1> to <5>, further comprising, after the step of applying the ink by an inkjet system, a step of applying a post-treatment liquid containing a liquid component and a resin onto the area on the recording medium where the ink has been applied. <7> The image recording method according to <6>, wherein the post-treatment liquid further comprises an additive (A) that is at least one selected from the group consisting of a light stabilizer and a UV absorber.

[0011] According to one aspect of the present disclosure, there is provided an image recording method capable of recording an image with excellent light resistance, color density, and image quality.

[0012] In this specification, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this specification, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0013] In this specification, the amount of each component in a composition means the total amount of the components in the composition unless otherwise specified, when the composition contains multiple substances corresponding to each component. In this specification, a combination of two or more preferred aspects is a more preferred aspect. In this specification, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0014] In this specification, the term "image" refers to a film in general, and "image recording" refers to the formation of an image (i.e., a film). The concept of "image" in this specification also includes a solid image.

[0015] In this specification, the term "(meth)acrylate" encompasses both acrylate and methacrylate, and the term "(meth)acrylic acid" encompasses both acrylic acid and methacrylic acid.

[0016] [Image Recording Method] The image recording method of the present disclosure includes: a step of applying a pretreatment liquid containing water and a flocculant onto a recording medium (hereinafter also referred to as a "pretreatment liquid applying step"); and a step of applying an ink containing water and a pigment onto the area of ​​the recording medium to which the pretreatment liquid has been applied (hereinafter also referred to as an "ink applying step") by an ink jet method, wherein at least the pretreatment liquid contains an additive (A) that is at least one selected from the group consisting of a light stabilizer and an ultraviolet absorber, and the total amount of additive (A) applied onto the recording medium is 0.05 g / m ２ ~2.00g / m ２ and the proportion of the amount of additive (A) applied by applying the pre-treatment liquid to the total amount of additive (A) applied (hereinafter also referred to as the "proportion due to application of the pre-treatment liquid") is 50% by mass to 100% by mass. The image recording method of the present disclosure may include other steps as necessary.

[0017] Generally, when recording an image using a pretreatment liquid containing water and a flocculant and an ink containing water and a pigment, it is sometimes necessary to improve the lightfastness of the recorded image. To improve the lightfastness of the image, it is possible to add at least one of a light stabilizer and an ultraviolet absorber to at least one of the pretreatment liquid and the ink. However, when attempting to improve the lightfastness of the image using this method, at least one of the color density and image quality of the image may be reduced. Furthermore, when attempting to maintain the color density and image quality of the image, the effect of improving the lightfastness may be reduced.

[0018] Regarding the above-mentioned problems, the image recording method of the present disclosure makes it possible to record images that are excellent in light resistance, color density, and image quality. The reason for this effect is believed to be as follows: When the total amount of additive (A) applied to the recording medium is 0.05 g / m ２ When the total amount of the additive (A) applied to the recording medium is 2.00 g / m or more, the effect of improving the lightfastness of the additive (A) is effectively exhibited, and the lightfastness of the image is ensured. ２ or less and the proportion due to the application of the pretreatment liquid (i.e., the proportion of the amount of additive (A) applied by application of the pretreatment liquid to the total amount of additive (A) applied onto the recording medium) is 50 mass % or more, the aggregation action of the aggregating agent in the pretreatment liquid is prevented from being inhibited by the additive (A), and as a result, the aggregation action of the aggregating agent in the pretreatment liquid is effectively exerted, and it is thought that the color density and image quality of the image are ensured.

[0019] First, the additive (A) contained in at least the pretreatment liquid will be described below, followed by a description of each step of the image recording method of the present disclosure.

[0020] <Additive (A)> The pretreatment liquid contains at least the additive (A), which is at least one selected from the group consisting of a light stabilizer and an ultraviolet absorber.

[0021] Here, "at least the pre-treatment liquid" means "among the pre-treatment liquid and the ink (and the post-treatment liquid, if used), at least the pre-treatment liquid." That is, in the present disclosure, the additive (A) may be contained not only in the pre-treatment liquid but also in the ink (and / or the post-treatment liquid, if used, described below). In this case, the additive (A) contained in the pre-treatment liquid and the additive (A) contained in the ink (and / or the post-treatment liquid, if used) may be the same or different, as long as they are at least one type selected from the group consisting of light stabilizers and ultraviolet absorbers.

[0022] (Total Amount of Additive (A) Applied) In the image recording method of the present disclosure, by applying a pretreatment liquid onto a recording medium, at least the additive (A) contained in the pretreatment liquid is applied onto the recording medium. Furthermore, when the ink contains additive (A), by applying the ink onto the recording medium, the additive (A) contained in the ink is also applied onto the recording medium. Furthermore, when a post-treatment liquid is used and the post-treatment liquid contains additive (A), by applying the post-treatment liquid onto the recording medium, the additive (A) contained in the post-treatment liquid is also applied onto the recording medium.

[0023] In the image recording method of the present disclosure, the total amount of additive (A) applied to the recording medium is 0.05 g / m ２ ~2.00g / m ２ Here, the total amount of additive (A) applied means the amount of additive (A) applied by applying the pretreatment liquid when the additive (A) is contained only in the pretreatment liquid, means the total amount of additive (A) applied by applying the pretreatment liquid and the total amount of additive (A) applied by applying the ink when the additive (A) is contained in both the pretreatment liquid and the ink, and means the total amount of additive (A) applied by applying the pretreatment liquid, the total amount of additive (A) applied by applying the ink and the total amount of additive (A) applied by applying the posttreatment liquid when the additive (A) is contained in all of the pretreatment liquid, the ink and the posttreatment liquid.

[0024] The total amount of additive (A) applied is 0.05 g / m ２ The total amount of the additive (A) applied is preferably 0.30 g / m from the viewpoint of further improving the light resistance of the image. ２ More preferably, 0.50 g / m ２ More preferably, 1.00 g / m ２ That's all.

[0025] The total amount of additive (A) applied is 2.00 g / m ２From the viewpoint of further improving the color density and / or image quality of the image, the total amount of additive (A) applied is preferably 1.75 g / m or less. ２ or less, more preferably 1.50 g / m ２ The following is the result.

[0026] (Proportion of the amount of additive (A) due to application of the pretreatment liquid in the total amount of additive (A) applied) In the image recording method of the present disclosure, the proportion of the amount of additive (A) due to application of the pretreatment liquid (i.e., the proportion of the amount of additive (A) applied by application of the pretreatment liquid) in the total amount of additive (A) applied is 50% by mass to 100% by mass. Having the proportion due to application of the pretreatment liquid be 50% by mass or more contributes to improving the color density and image quality of the image. From the viewpoint of further improving the color density and image quality of the image, the proportion due to application of the pretreatment liquid is preferably 65% ​​by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass.

[0027] Light Stabilizer One option for additive (A) is a light stabilizer.

[0028] The light stabilizer preferably contains a hindered amine compound, and more preferably contains a hindered amine compound (I) containing a structure represented by the following formula (I).

[0029]

[0030] In formula (I), R １ represents a hydrogen atom, a hydroxy group, an alkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, or an acyloxy group having 1 to 40 carbon atoms; R ２ ~R ５ each independently represents an alkyl group having 1 to 5 carbon atoms, and two * each represent a bonding position. ２ and R ３ , and R ４ and R ５ may be linked via an oxygen atom, a nitrogen atom, or a sulfur atom, or may be linked directly to form a ring.

[0031] In formula (I), R １is preferably a hydrogen atom, a hydroxy group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an acyloxy group having 1 to 20 carbon atoms, and more preferably a hydrogen atom, a hydroxy group, an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, or an acyloxy group having 1 to 16 carbon atoms. ２ ~R ５ are each independently preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0032] The molecular weight of the hindered amine compound (for example, hindered amine compound (I)) is preferably 1,000 or less.

[0033] (UV Absorber) One option for additive (A) is a UV absorber.

[0034] The ultraviolet absorber preferably contains at least one selected from the group consisting of benzotriazole compounds and triazine compounds.

[0035] The benzotriazole compound is preferably a compound containing a benzotriazole structure and having a molecular weight of 1000 or less. The triazine compound is preferably a compound containing a triazine structure and having a molecular weight of 1000 or less.

[0036] <Pretreatment Liquid Application Step> The image recording method of the present disclosure includes a pretreatment liquid application step, which is a step of applying a pretreatment liquid containing water and a flocculant onto a recording medium.

[0037] (Recording Medium) There are no particular limitations on the recording medium, and either a permeable substrate or a non-permeable substrate may be used, but a permeable substrate is preferred.

[0038] In this disclosure, a permeable substrate refers to a substrate having a water absorption rate (unit: mass %, measurement time: 24 hours) of 0.2 or more according to ASTM test method ASTM D570. In this disclosure, a non-permeable substrate refers to a substrate having a water absorption rate (unit: mass %, measurement time: 24 hours) of less than 0.2 according to ASTM test method ASTM D570.

[0039] From the viewpoint of further improving the image quality, the permeable substrate has a water absorption coefficient Ka of 0.05 mL / m ２ ・ms １／２ The water absorption coefficient Ka of the permeable substrate is preferably 0.05 mL / m or more. ２ ・ms １／２ ~0.5 mL / m ２ ・ms １／２ More preferably, 0.1 mL / m ２ ・ms １／２ ~0.4 mL / m ２ ・ms １／２ More preferably, 0.2 mL / m ２ ・ms １／２ ~0.3 mL / m ２ ・ms １／２ is more preferred.

[0040] The water absorption coefficient Ka is the same as that described in JAPAN TAPPI Paper and Pulp Testing Method No. 51:2000 (published by the Paper and Pulp Technology Association). The absorption coefficient Ka is a value calculated from the difference in the amount of water transferred between a contact time of 100 ms and a contact time of 900 ms using an automatic scanning absorption meter KM500Win (manufactured by Kumagai Riki Co., Ltd.).

[0041] The permeable substrate preferably includes paper. In this case, the permeable substrate may be a permeable substrate consisting solely of paper (e.g., high-quality paper, neutral paper, etc.), or may be a permeable substrate including paper and a coating layer (e.g., art paper, coated paper, lightweight coated paper, lightly coated paper, etc.). The coating layer preferably includes an inorganic pigment. The inorganic pigment is not particularly limited, but is preferably at least one selected from silica, kaolin, clay, calcined clay, zinc oxide, tin oxide, magnesium sulfate, aluminum oxide, aluminum hydroxide, pseudoboehmite, calcium carbonate, calcium bicarbonate, satin white, aluminum silicate, smectite, zeolite, magnesium silicate, magnesium carbonate, magnesium oxide, and diatomaceous earth, and more preferably calcium carbonate, calcium bicarbonate, silica, and kaolin.

[0042] Commercially available products may be used as the permeable substrate containing paper. Examples of commercially available products include: fine paper (A) such as "OK Prince Bond" manufactured by Oji Paper Co., Ltd., "Shiraoi" manufactured by Nippon Paper Industries Co., Ltd., and "New NPI Bond" manufactured by Nippon Paper Industries Co., Ltd.; Form paper such as "NPi Form" manufactured by Nippon Paper Industries Co., Ltd.; fine coated paper such as "Silver Diamond" manufactured by Nippon Paper Industries Co., Ltd.; lightly coated paper such as "OK Everlight Coat" manufactured by Oji Paper Co., Ltd. and "Aurora S" manufactured by Nippon Paper Industries Co., Ltd.; lightweight coated paper (A3) such as "OK Coat L" manufactured by Oji Paper Co., Ltd. and "Aurora L" manufactured by Nippon Paper Industries Co., Ltd.; coated paper (A2, B2) such as "OK Top Coat +" manufactured by Oji Paper Co., Ltd. and "Aurora Coat" manufactured by Nippon Paper Industries Co., Ltd.; art paper (A1) such as "OK Kinto +" manufactured by Oji Paper Co., Ltd. and "Tokubishi Art" manufactured by Mitsubishi Paper Mills Co., Ltd.; various photo papers for inkjet recording; "Bon Ivory" manufactured by Oji Paper Co., Ltd.; Examples include "Calorina C2S" manufactured by Industrial Corporation; "CartaIntegra" manufactured by Metsaboard; "VJFP Series" manufactured by YUPO; and "MAGNO (registered trademark) Gross," a coated paper manufactured by Sappi.

[0043] (Pretreatment Liquid) The pretreatment liquid contains water and a flocculant.

[0044] -Water- The pretreatment liquid contains water. The water content is preferably 50% by mass or more, and more preferably 60% by mass or more, based on the total amount of the pretreatment liquid. The upper limit of the water content, although it depends on the amounts of other components, is preferably 90% by mass or less, and more preferably 80% by mass or less, based on the total amount of the pretreatment liquid.

[0045] - Flocculant - The pretreatment solution of the present disclosure contains at least one flocculant. Examples of the flocculant include organic acids, organic acid salts, polyvalent metal compounds, and metal complexes. As the flocculant, compounds described in publicly known publications such as paragraphs 0122 to 0130 of WO 2020 / 195360 may be used.

[0046] The flocculant preferably contains at least one selected from the group consisting of organic acids and organic acid salts.

[0047] The organic acid is an organic compound having an acidic group. Examples of the acidic group include a phosphate group, a phosphonate group, a phosphinate group, a sulfate group, a sulfonic acid group, a sulfinic acid group, and a carboxy group. Among these, from the viewpoint of the aggregation rate of the ink, the acidic group is preferably a phosphate group or a carboxy group, and more preferably a carboxy group.

[0048] It is preferable that at least a portion of the acidic groups is dissociated in the pretreatment liquid.

[0049] Examples of organic compounds having a carboxy group include (meth)acrylic acid, poly(meth)acrylic acid, acetic acid, formic acid, benzoic acid, glycolic acid, malonic acid, malic acid (preferably DL-malic acid), maleic acid, succinic acid, glutaric acid, pimelic acid, adipic acid, fumaric acid, citric acid, tartaric acid, phthalic acid, 4-methylphthalic acid, lactic acid, pyrrolidonecarboxylic acid, pyronecarboxylic acid, pyrrolecarboxylic acid, furancarboxylic acid, pyridinecarboxylic acid, coumaric acid, thiophenecarboxylic acid, and nicotinic acid.

[0050] Among these, from the viewpoint of the aggregation speed of the ink, the organic compound having a carboxy group is preferably a divalent or higher carboxylic acid (hereinafter also referred to as a polycarboxylic acid), and more preferably a dicarboxylic acid.

[0051] Specifically, the polycarboxylic acid is preferably malonic acid, malic acid, maleic acid, succinic acid, glutaric acid, pimelic acid, adipic acid, fumaric acid, tartaric acid, 4-methylphthalic acid, or citric acid, and more preferably malonic acid, malic acid, tartaric acid, succinic acid, glutaric acid, pimelic acid, adipic acid, or citric acid.

[0052] The organic acid preferably has a low pKa (for example, 1.0 to 5.0), which reduces the surface charge of particles such as pigments and resin particles in the ink, which are stabilized by weakly acidic functional groups such as carboxyl groups, by contacting them with an organic acid having an even lower pKa, thereby lowering dispersion stability.

[0053] The organic acid preferably has a low pKa, high solubility in water, and a valence of at least 2. Furthermore, the organic acid more preferably has a high buffering capacity in a pH range lower than the pKa of the functional group (e.g., carboxy group) that stabilizes the dispersion of the particles in the ink.

[0054] The organic acid salts include alkali metal salts of organic acids and polyvalent metal salts of organic acids, and preferably polyvalent metal salts of organic acids.The polyvalent metal salts include, for example, salts of alkaline earth metals (for example, magnesium, calcium) of Group 2 of the periodic table, salts of transition metals (for example, lanthanum) of Group 3 of the periodic table, salts of metals (for example, aluminum) of Group 13 of the periodic table, and salts of lanthanides (for example, neodymium).The polyvalent metal salts are preferably calcium salts, magnesium salts, or aluminum salts, and more preferably calcium salts or magnesium salts.

[0055] The polyvalent metal salt of an organic acid is preferably at least partially dissociated into polyvalent metal ions and counter ions in the pretreatment liquid.

[0056] The proportion of the organic acid and organic acid salt in the flocculant is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass.

[0057] The content of the flocculant in the pretreatment liquid is preferably 1.0% by mass to 40% by mass, more preferably 3.0% by mass to 30% by mass, and even more preferably 10% by mass to 30% by mass, based on the total amount of the pretreatment liquid.

[0058] —Additive (A)— The pre-treatment liquid contains the aforementioned additive (A). The content of the additive (A) in the pre-treatment liquid, relative to the total amount of the pre-treatment liquid, is preferably 1.0 to 20% by mass, more preferably 3.0 to 15% by mass, and even more preferably 3.0 to 10% by mass.

[0059] —Organic Solvent— The pretreatment liquid may contain at least one organic solvent. The type of organic solvent is not limited, and examples thereof include: monoalcohols having 1 to 4 carbon atoms; diols such as 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, 1,2-octanediol, 1,2-hexanediol, 1,2-pentanediol, and 4-methyl-1,2-pentanediol; triols such as glycerin, 1,2,6-hexanetriol, and trimethylolpropane; alkylene glycols such as ethylene glycol and propylene glycol; alkylene glycol monoalkyl ethers such as ethylene glycol monoalkyl ethers and propylene glycol monoalkyl ethers; polyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, and polyoxyethylene polyoxypropylene glycol; Examples thereof include polyalkylene glycol ethers such as diethylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, tripropylene glycol monoalkyl ether, and polyoxypropylene glyceryl ether; 2-pyrrolidone, and N-methyl-2-pyrrolidone.

[0060] The content of the organic solvent is preferably 1% by mass to 20% by mass, and more preferably 3% by mass to 10% by mass, based on the total amount of the pretreatment liquid.

[0061] -Surfactant- The pretreatment liquid may contain at least one surfactant. The type of surfactant is not particularly limited, and may be any of anionic surfactants, cationic surfactants, betaine-based surfactants, and nonionic surfactants. Examples of surfactants include acrylic surfactants, fluorine-based surfactants, and silicone-based surfactants. The surfactant may also function as a defoaming agent.

[0062] The content of the surfactant is preferably 0.01% by mass to 6% by mass, and more preferably 0.1% by mass to 4% by mass, based on the total amount of the pretreatment liquid.

[0063] Other Components The pretreatment liquid may contain other components in addition to those described above, as necessary. Examples of other components that can be contained in the pretreatment liquid include known additives such as solid wetting agents, colloidal silica, inorganic salts, anti-fading agents, emulsion stabilizers, penetration enhancers, UV absorbers, preservatives, antifungal agents, pH adjusters, viscosity adjusters, rust inhibitors, chelating agents, and water-soluble polymer compounds (for example, the water-soluble polymer compounds described in paragraphs 0026 to 0080 of JP 2013-001854 A).

[0064] -Physical Properties of Pretreatment Solution- The pH of the pretreatment solution is preferably 0.5 to 7.0, more preferably 3.0 to 6.0, and even more preferably 3.0 to 5.0. Here, pH refers to the pH at 25°C. The pH is measured at 25°C using, for example, a pH meter (e.g., a pH meter manufactured by Toa DKK Corporation (model number "HM-31")).

[0065] The viscosity of the pretreatment liquid is preferably 0.5 mPa·s to 20 mPa·s, and more preferably 1 mPa·s to 10 mPa·s. The viscosity is a value measured at 30°C using a viscometer. The viscosity is measured at 30°C using a viscometer, for example, a TV-22 type viscometer manufactured by Toki Sangyo Co., Ltd.

[0066] The surface tension of the pretreatment liquid is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and even more preferably 30 mN / m to 45 mN / m. The surface tension is a value measured at a temperature of 25°C. The surface tension is measured at 25°C using a surface tensiometer, for example, an automatic surface tensiometer (product name "CBVP-Z" manufactured by Kyowa Interface Science Co., Ltd.) by the plate method.

[0067] (Application of Pretreatment Liquid) The method for applying the pretreatment liquid is not particularly limited, and examples thereof include known methods such as a coating method, a dipping method, and an inkjet recording method.

[0068] Examples of the coating method include known coating methods using a bar coater, extrusion die coater, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, reverse roll coater, and the like.

[0069] The amount of the pretreatment liquid applied is preferably 1 g / m ２ ~30g / m ２ , more preferably 2 g / m ２ ~25g / m ２ , more preferably 5 g / m ２ ~20g / m ２ is.

[0070] The amount of additive (A) applied by applying the pretreatment liquid is preferably 0.05 g / m ２ ~2.00g / m ２ The amount of additive (A) applied by applying the pretreatment liquid is 0.05 g / m ２ The amount of the additive (A) applied by applying the pretreatment liquid is preferably 0.30 g / m from the viewpoint of further improving the light resistance of the image. ２ More preferably, 0.50 g / m ２ More preferably, 1.00 g / m ２ The amount of additive (A) applied by applying the pretreatment liquid is preferably 1.75 g / m from the viewpoint of further improving the color density and / or image quality of the image. ２ or less, more preferably 1.50 g / m ２ The following is the result.

[0071] (Heat-Drying of Pretreatment Liquid) The pretreatment liquid application step may include applying the pretreatment liquid onto the recording medium and heat-drying the pretreatment liquid applied onto the recording medium. Examples of means for heat-drying the pretreatment liquid include known heating means such as a heater, known air blowing means such as a dryer, and a combination of these.

[0072] Examples of methods for heating and drying the pretreatment liquid include a method of applying heat using a heater or the like from the side opposite to the side of the recording medium to which the pretreatment liquid has been applied, a method of applying warm or hot air to the side of the recording medium to which the pretreatment liquid has been applied, a method of applying heat using an infrared heater from the side of the recording medium to which the pretreatment liquid has been applied or the side opposite to the side to which the pretreatment liquid has been applied, and a combination of these methods.

[0073] The heating temperature during heat drying of the pretreatment liquid is preferably 45° C. or higher, more preferably 50° C. or higher, and particularly preferably 55° C. or higher. The upper limit of the heating temperature is not particularly limited and is, for example, 150° C. The heating time is not particularly limited, but is preferably 0.5 to 30 seconds, more preferably 1 to 10 seconds, and particularly preferably 1 to 5 seconds.

[0074] <Ink Application Step> The image recording method of the present disclosure includes an ink application step. The ink application step is a step of applying, by inkjet printing, an ink containing water and a pigment onto an area on the recording medium to which the pretreatment liquid has been applied. In this step, by applying the ink onto the area on the recording medium to which the pretreatment liquid has been applied, components in the ink (e.g., the pigment) are aggregated on the recording medium by the action of an aggregating agent derived from the pretreatment liquid, thereby obtaining an image.

[0075] (Ink) The ink contains water and a pigment.

[0076] -Water- The water content is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, relative to the total amount of the ink. The upper limit of the water content depends on the amounts of other components. Examples of upper limits of the water content relative to the total amount of the ink include 90% by mass and 80% by mass.

[0077] - Pigment - The ink of the present disclosure contains at least one pigment. The pigment may be an organic pigment or an inorganic pigment.

[0078] Examples of organic pigments include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments or polycyclic pigments are preferred. Examples of azo pigments include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of polycyclic pigments include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments. Examples of dye chelates include basic dye chelates and acid dye chelates.

[0079] Examples of inorganic pigments include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black.

[0080] Examples of the pigment include those described in "Dictionary of Pigments" edited by Seijiro Ito (published in 2000), "Industrial Organic Pigments" by W. Herbst and K. Hunger, and JP-A Nos. 2002-12607, 2002-188025, 2003-26978, and 2003-342503.

[0081] The volume average particle diameter of the pigment is preferably 10 nm to 200 nm, more preferably 30 nm to 180 nm, and even more preferably 50 nm to 160 nm. When the volume average particle diameter is 200 nm or less, color reproducibility is improved and ejection properties are improved when recording images using an inkjet recording method. Furthermore, when the volume average particle diameter is 10 nm or more, light resistance is improved.

[0082] The particle size distribution of the pigment is not particularly limited, and may be either a broad particle size distribution or a monodisperse particle size distribution. Two or more pigments having a monodisperse particle size distribution may be mixed and used.

[0083] The volume average particle size and particle size distribution of the pigment are values ​​measured using a particle size distribution measuring device (for example, Microtrac UPA (registered trademark) EX150 manufactured by Nikkiso Co., Ltd.).

[0084] The content of the pigment is preferably 0.2% by mass to 20.0% by mass, and more preferably 1.0% by mass to 10.0% by mass, relative to the total amount of the ink.

[0085] - Pigment dispersant - The ink of the present disclosure may contain a pigment dispersant. In the present disclosure, a pigment dispersant is a compound that has the function of dispersing a pigment. The pigment dispersant adsorbs to the surface of the pigment, covering at least a portion of the surface of the pigment, thereby enabling the pigment to be dispersed in water. An ink of the present disclosure in an embodiment that contains a pigment dispersant is preferably prepared using a pigment dispersion that contains a pigment and a pigment dispersant. Note that when a self-dispersing pigment that can be dispersed in water even in the absence of a pigment dispersant is used as the pigment, the ink does not need to contain a pigment dispersant.

[0086] The form of the pigment dispersant is not particularly limited, and may be any of a random resin, a block resin, and a graft resin. The pigment dispersant may also be a resin having a crosslinked structure.

[0087] In this disclosure, a resin refers to a compound having a weight average molecular weight (Mw) of 1,000 or more.

[0088] In this disclosure, the weight average molecular weight (Mw) refers to a value measured by gel permeation chromatography (GPC). Measurements by gel permeation chromatography (GPC) are performed using an HLC (registered trademark)-8020GPC (manufactured by Tosoh Corporation) as a measuring device, three TSKgel (registered trademark) Super Multipore HZ-H columns (4.6 mm ID x 15 cm, manufactured by Tosoh Corporation), and THF (tetrahydrofuran) as an eluent. Measurements are performed using an RI detector at a sample concentration of 0.45% by mass, a flow rate of 0.35 ml / min, a sample injection volume of 10 μl, and a measurement temperature of 40°C. The calibration curve is prepared from eight samples of "Standard Sample TSK Standard, Polystyrene" manufactured by Tosoh Corporation: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000", and "n-propylbenzene".

[0089] Water-soluble organic solvent The ink may contain at least one water-soluble organic solvent, which further improves the ejection properties of the ink.

[0090] In the present disclosure, the term "water-soluble" in "water-soluble organic solvent" means that 1 g or more of the solvent dissolves in 100 g of water at 25°C.

[0091] The type of water-soluble organic solvent that can be contained in the ink is not limited, and examples thereof include: monoalcohols having 1 to 4 carbon atoms; diols such as 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, 1,2-octanediol, 1,2-hexanediol, 1,2-pentanediol, and 4-methyl-1,2-pentanediol; triols such as glycerin, 1,2,6-hexanetriol, and trimethylolpropane; alkylene glycols such as ethylene glycol and propylene glycol (also known as 1,2-propanediol); alkylene glycol monoalkyl ethers such as ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether; Polyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, and polyoxyethylene polyoxypropylene glycol; polyalkylene glycol ethers such as diethylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, tripropylene glycol monoalkyl ether, and polyoxypropylene glyceryl ether; 2-pyrrolidone, N-methyl-2-pyrrolidone; and the like.

[0092] The water-soluble organic solvent in the ink preferably contains at least one selected from the group consisting of alkylene glycols and alkylene glycol monoalkyl ethers.

[0093] The content of the water-soluble organic solvent is preferably 10% by mass to 50% by mass, and more preferably 15% by mass to 40% by mass, based on the total amount of the ink.

[0094] -Surfactant- The ink may contain at least one surfactant. The type of surfactant is not particularly limited, and may be any of anionic surfactants, cationic surfactants, betaine surfactants, and nonionic surfactants. Examples of surfactants include acrylic surfactants, fluorine-based surfactants, and silicone-based surfactants.

[0095] The content of the surfactant is preferably 0.01% by mass to 6% by mass, and more preferably 0.1% by mass to 4% by mass, based on the total amount of the ink.

[0096] -Additive (A)- The ink may contain the additive (A) described above. When the ink contains the additive (A), the additive (A) in the ink and the additive (A) in the pretreatment liquid may be the same or different. When the ink contains the additive (A) described above, from the viewpoint of ink ejection stability, the content of the additive (A) in the ink is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less, relative to the total amount of the ink.

[0097] Other Components The ink may contain other components in addition to those described above, as necessary. Examples of other components that can be contained in the ink include known additives such as resin particles, water-soluble resins, colloidal silica, solid wetting agents, inorganic salts, anti-fading agents, emulsion stabilizers, penetration enhancers, UV absorbers, preservatives, antifungal agents, pH adjusters, viscosity adjusters, rust inhibitors, and chelating agents.

[0098] -Physical Properties of Ink- The pH (25°C) of the ink is preferably 6.0 to 11.0, more preferably 6.5 to 10.0, and even more preferably 7.0 to 9.0. The pH of the ink is measured in the same manner as the pH of the pretreatment liquid.

[0099] The viscosity of the ink (30°C) is preferably 1.2 mPa·s to 15.0 mPa·s, more preferably 2.0 mPa·s to 13.0 mPa·s, and even more preferably 2.5 mPa·s to 10.0 mPa·s. The viscosity of the ink is measured in the same manner as the viscosity of the pretreatment liquid.

[0100] The surface tension of the ink is preferably 60 mN / m or less, more preferably 20 mN / m to 55 mN / m, and even more preferably 30 mN / m to 50 mN / m. The surface tension of the ink is measured in the same manner as the surface tension of the pretreatment liquid.

[0101] (Application of ink by inkjet method) Known inkjet methods can be used, including, for example, a charge control method that uses electrostatic attraction to eject ink, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezoelectric element, an acoustic inkjet method that converts an electric signal into an acoustic beam and irradiates the ink with the acoustic beam to eject the ink by using radiation pressure, and a thermal inkjet (Bubble Jet (registered trademark)) method that heats the ink to form bubbles and uses the resulting pressure.

[0102] Inkjet heads used in inkjet systems include a shuttle system, which uses a short serial head and performs printing by scanning the head in the width direction of the recording medium, and a line system, which uses a line head in which printing elements are arranged to correspond to the entire area of ​​one side of the recording medium.

[0103] In the line method, a pattern can be formed over the entire surface of a recording medium by scanning the recording medium in a direction intersecting the arrangement direction of the recording elements, eliminating the need for a transport system such as a carriage for scanning a short head. Furthermore, the line method does not require complex scanning control of the carriage movement and the recording medium, and only the recording medium moves, making it possible to achieve a faster recording speed than the shuttle method.

[0104] The droplet volume of ink ejected from the inkjet head is preferably 1 pL (picoliter) to 100 pL, more preferably 1.5 pL to 80 pL, and even more preferably 1.8 pL to 50 pL.

[0105] The amount of ink applied is preferably 2 g / m ２ ~30g / m ２ , more preferably 5 g / m ２ ~20g / m ２ , more preferably 8 g / m２ ~15g / m ２ is.

[0106] The amount of additive (A) applied by applying the ink is preferably 0.50 g / m from the viewpoint of ink ejection stability. ２ or less, more preferably 0.40 g / m ２ More preferably, 0.30 g / m or less ２ More preferably, 0.20 g / m or less ２ The following is the result.

[0107] The application step may include heating and drying the ink applied to the recording medium. Examples of the heating and drying method include a known heating method such as a heater, a known air blowing method such as a dryer, and a combination of these.

[0108] Specifically, methods for heating the recording medium include a method of applying heat using a heater or the like from the side opposite to the ink-applied side of the recording medium; a method of applying warm or hot air to the ink-applied side of the recording medium; a method of applying heat using an infrared heater from the ink-applied side of the recording medium or from the side opposite to this side; and a combination of these methods.

[0109] The heating temperature during heat drying of the ink is preferably 55° C. or higher, more preferably 60° C. or higher, and particularly preferably 65° C. or higher. The upper limit of the heating temperature is not particularly limited, and is, for example, 150° C. The heating time is not particularly limited, but is preferably 1 to 60 seconds, more preferably 3 to 45 seconds, and particularly preferably 5 to 30 seconds.

[0110] <Post-treatment liquid application step> The image recording method of the present disclosure may include a post-treatment liquid application step after the ink application step. The post-treatment liquid application step is a step of applying a post-treatment liquid containing a liquid component and a resin onto an area on a recording medium to which ink has been applied. When the image recording method of the present disclosure includes a post-treatment liquid application step, the ink film (i.e., the image) can be coated with a resin film derived from the post-treatment liquid. This further improves the strength of the image (for example, scratch resistance, abrasion resistance, etc.).

[0111] (Post-treatment liquid) The post-treatment liquid contains a liquid component and a resin.

[0112] The post-treatment liquid contains at least one resin. The resin contained in the post-treatment liquid is preferably at least one selected from the group consisting of acrylic resin, ester resin, a mixture of acrylic resin and ester resin, composite particles containing acrylic resin and ester resin, styrene-acrylic resin, and polyurethane resin.

[0113] In the present disclosure, acrylic resin refers to a polymer (homopolymer or copolymer) of raw material monomers containing at least one selected from the group consisting of acrylic acid, derivatives of acrylic acid (e.g., acrylic acid esters), methacrylic acid, and derivatives of methacrylic acid (e.g., methacrylic acid esters).

[0114] The glass transition temperature (Tg) of the resin contained in the post-treatment liquid is preferably 0°C to 200°C, and more preferably 30°C to 100°C. Here, the glass transition temperature (Tg) of the resin particles is the measured Tg obtained by actual measurement. For the method of measuring the measured Tg, see paragraph 0111 of JP2015-25076A.

[0115] The content of the resin in the post-treatment liquid is preferably 1% by mass to 30% by mass, and more preferably 1% by mass to 25% by mass, based on the total amount of the post-treatment liquid.

[0116] - Liquid Component - The post-treatment liquid contains a liquid component. Examples of the liquid component include water, an organic solvent, and a polymerizable monomer (for example, a monofunctional or difunctional (meth)acrylic monomer). The content of the liquid component is preferably 50% by mass or more, and more preferably 60% by mass or more, relative to the total amount of the post-treatment liquid. The upper limit of the content of the liquid component, although it depends on the amounts of other components, is preferably 90% by mass or less, and more preferably 80% by mass or less, relative to the total amount of the post-treatment liquid.

[0117] -Surfactant- The post-treatment liquid may contain at least one surfactant. The type of surfactant is not particularly limited, and may be any of anionic surfactants, cationic surfactants, betaine-based surfactants, and nonionic surfactants. Examples of surfactants include acrylic surfactants, fluorine-based surfactants, and silicone-based surfactants. The surfactant may also function as a defoaming agent.

[0118] The content of the surfactant is preferably 0.01 to 6% by mass, and more preferably 0.1 to 4% by mass, based on the total amount of the post-treatment liquid.

[0119] -Additive (A)- The post-treatment liquid may contain the additive (A) described above. When the post-treatment liquid contains the additive (A), the additive (A) in the post-treatment liquid and the additive (A) in the pre-treatment liquid may be the same or different. When the post-treatment liquid contains the additive (A), from the viewpoint of the texture of the image recorded matter (i.e., the image recorded matter comprising a recording medium and an image), the content of the additive (A) in the post-treatment liquid is preferably 10% by mass or less, more preferably 6.0% by mass or less, and even more preferably 4.0% by mass or less, relative to the total amount of the post-treatment liquid.

[0120] -Other Components- The post-treatment liquid may contain other components in addition to those described above, as necessary. Examples of other components that can be contained in the post-treatment liquid include the same components as those that can be contained in the pre-treatment liquid.

[0121] -Physical Properties of Post-Treatment Solution- The pH of the post-treatment solution is preferably 3.0 to 10.0, more preferably 4.0 to 9.5, and even more preferably 5.0 to 9.0. Here, pH refers to the pH at 25°C. The pH is measured at 25°C using, for example, a pH meter (for example, a pH meter manufactured by Toa DKK Corporation (model number "HM-31")).

[0122] The viscosity of the post-treatment liquid is preferably 3.0 mPa·s to 100 mPa·s, and more preferably 5.0 mPa·s to 50 mPa·s. The viscosity is a value measured at 30°C using a viscometer. The viscosity is measured at 30°C using a viscometer, for example, a TV-22 type viscometer manufactured by Toki Sangyo Co., Ltd.

[0123] The surface tension of the post-treatment liquid is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and even more preferably 30 mN / m to 45 mN / m. The surface tension is a value measured at a temperature of 25°C. The surface tension is measured at 25°C using a surface tensiometer, for example, an automatic surface tensiometer (product name "CBVP-Z") manufactured by Kyowa Interface Science Co., Ltd., by the plate method.

[0124] (Application of Post-Treatment Liquid) The method for applying the post-treatment liquid is not particularly limited, and examples thereof include known methods such as printing methods (for example, flexographic printing methods), coating methods, immersion methods, and inkjet recording methods.

[0125] The amount of post-treatment liquid applied is preferably 2 g / m ２ ~30g / m ２ , more preferably 3 g / m ２ ~25g / m ２ , more preferably 5 g / m ２ ~25g / m ２ is.

[0126] The amount of additive (A) applied by applying the post-treatment liquid is preferably 0.50 g / m from the viewpoint of the texture of the image recorded matter (i.e., the image recorded matter containing the recording medium and the image). ２ or less, more preferably 0.40 g / m ２ More preferably, 0.30 g / m or less ２ More preferably, 0.20 g / m or less ２ The following is the result.

[0127] (Heat-drying of post-treatment liquid) The post-treatment liquid application step may include applying a post-treatment liquid onto a recording medium and heat-drying the post-treatment liquid applied onto the recording medium. Preferred aspects of heat-drying the post-treatment liquid are the same as preferred aspects of heat-drying the pre-treatment liquid.

[0128] Examples of the present disclosure will be shown below, but the present disclosure is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass.

[0129] Examples 1 to 46, Comparative Examples 1 to 6 <Ink Preparation> The components listed in Table 1 below were mixed and coarse particles were removed using a 1 μm filter to obtain cyan ink (IC-1), magenta inks (IM-1) and (IM-2), yellow inks (IY-1) and (IY-2), and black ink (IK-1). In Table 1, the "remaining amount," which is the water content, refers to the amount remaining so that the total of all components is 100% by mass. In Table 1, "*1" refers to the amount of additive (A)-containing composition corresponding to the additive (A) content shown in Tables 2 and 3. In Table 1, blank spaces and "-" both indicate that the corresponding component is not contained. In all of the inks, the volume average particle diameter of the pigment was in the range of 106 nm to 130 nm, the pH (25°C) was in the range of 7.7 to 8.0, the viscosity (30°C) was in the range of 3.6 to 3.8, the surface tension (25°C) was in the range of 34.0 mN / m to 37.0 mN / m, and the electrical conductivity was in the range of 37 mS / m to 90 mS / m. In Examples 1 to 46 and Comparative Examples 1 to 6, a black ink (IK-1), a cyan ink (IC-1), a magenta ink (IM-1), and a yellow ink (IY-1) were used, and in Examples 101 and 102 described below, a black ink (IK-1), a cyan ink (IC-1), a magenta ink (IM-2), and a yellow ink (IY-2) were used.

[0130]

[0131] Details of the components in Table 1 are as follows: Pro-Jet APD1000 Cyan: Pigment dispersion containing Pigment Blue 15:3 (pigment solids concentration: 14.1%, average pigment particle size: 106 nm), manufactured by FUJIFILM Imaging Colorants. Pro-Jet APD1000 Magenta: Pigment dispersion containing Pigment Red 122 (pigment solids concentration: 14.0%, average pigment particle size: 117 nm), manufactured by FUJIFILM Imaging Colorants. Pro-Jet APD1000 Red: Pigment dispersion containing Pigment Red 254 (pigment solids concentration: 14.3%, average pigment particle size: 115 nm), manufactured by FUJIFILM Imaging Colorants. Pro-Jet APD1000 Yellow-TP: Pigment dispersion containing Pigment Yellow 74 (pigment solids concentration: 15.3%, average pigment particle size: 129 nm), manufactured by FUJIFILM Imaging Colorants. Pro-Jet APD1000 Yellow-LF: Pigment dispersion containing Pigment Yellow 155 (pigment solids concentration: 14.7%, average pigment particle size: 140 nm), manufactured by FUJIFILM Imaging Colorants. Pro-Jet APD1000 Black: Pigment dispersion containing Pigment Black 7 (pigment solids concentration: 14.3%, average pigment particle size: 115 nm), manufactured by FUJIFILM Imaging Colorants. Polyvinylpyrrolidone... Polyvinylpyrrolidone K15 (average molecular weight 10,000), manufactured by Tokyo Chemical Industry Co., Ltd. Surfynol 465... acetylene glycol surfactant, manufactured by Nissin Chemical Industry Co., Ltd. Snowtex XS... colloidal silica, manufactured by Nissan Chemical Industries, Ltd. BYK-024... antifoaming agent, manufactured by BYK Japan K.K.

[0132] <Preparation of Pretreatment Liquid (PR-1)> The following components were mixed and filtered using a 1 μm filter to obtain a pretreatment liquid (PR-1) with a pH of 4.3 (25° C.).

[0133] - Components of pre-treatment liquid (PR-1) - Malonic acid: 10.90% by mass Citric acid: 13.40% by mass Diethylene glycol monobutyl ether: 2.00% by mass Potassium hydroxide: 7.30% by mass BYK-038 (defoaming agent, manufactured by BYK Japan KK): 0.05% by mass Polyacrylic acid 25,000 (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.): 0.95% by mass Additive (A) shown in Table 2 or Table 3: Content shown in Table 2 or Table 3 Ion-exchanged water: Remaining amount to make the total 100% by mass

[0134] <Preparation of Post-Treatment Solution (PT-1)> The following components were mixed and filtered using a 1 μm filter to obtain a post-treatment solution (PR-1) with a pH of 4.3 (25° C.).

[0135] - Components of post-treatment liquid (PT-1) - Propylene glycol: 2.00% by mass; BYK-038 (defoaming agent, manufactured by BYK Japan KK): 0.05% by mass; Neopelex G-65: 0.85% by mass; JONCRYL 60: 5.1% by mass as solid content (i.e., amount of resin); JONCRYL 537: 4.57% by mass as solid content (i.e., amount of resin); Additive (A) shown in Table 2 or Table 3: Content shown in Table 2 or Table 3; Ion-exchanged water: Remaining amount to make the total 100% by mass

[0136] Details of the following components in the post-treatment liquid are as follows: Neopelex G-65: sodium dodecylbenzenesulfonate (soft type) (solid content: 65%, manufactured by Kao Corporation) JONCRYL 60: aqueous ammonia solution of styrene-acrylic resin (Tg: 85°C, solid content: 34% by mass, manufactured by BASF) JONCRYL 537: aqueous dispersion of styrene-acrylic resin (Tg: 44°C, particle size (D95): 61 nm, solid content: 45.7% by mass, manufactured by BASF)

[0137] <Compositions containing additive (A) in Table 2 or Table 3> Details of the compositions containing additive (A) in Table 2 or Table 3 are as follows: The content of additive (A) in Table 2 or Table 3 means the amount of the active ingredient (i.e., the light stabilizer or ultraviolet absorber as additive (A)) in each of the compositions containing additive (A) described below.

[0138] Additive (A)-containing composition A-1: ​​Tinuvin 123-DW(N)...an aqueous dispersion of an acrylic polymer containing a hindered amine-based light stabilizer having the following structure (active ingredient (i.e., light stabilizer as additive (A)) 30% by mass, total solids content 50% by mass, manufactured by BASF)

[0139]

[0140] Additive (A)-containing composition A-2: Tinuvin 249-DW(N) ... neutral hindered amine light stabilizer (active ingredient (i.e., light stabilizer as additive (A)) 40% by mass, total solids content 50% by mass, manufactured by BASF)

[0141] Additive (A)-containing composition A-3: Hostavin 3051-2 DISP...aqueous dispersion of a light stabilizer having the following structure (active ingredient (i.e., light stabilizer as additive (A)) 52% by mass, manufactured by Clariant Chemicals K.K.)

[0142]

[0143] Additive (A)-containing composition A-4: CHIGUARD 5400WB...an emulsion containing a triazine-based ultraviolet absorber having the following structure (active ingredient (i.e., ultraviolet absorber as additive (A)) 30% by mass, total solids content 31% to 34% by mass, manufactured by Cbitec)

[0144]

[0145] Additive (A)-containing composition A-5: Tinuvin 400-DW(N): an aqueous dispersion of an acrylic polymer containing a triazine-based ultraviolet absorber having the following structure (active ingredient (i.e., ultraviolet absorber as additive (A)) 20% by mass, total solids content 40% by mass, manufactured by BASF)

[0146]

[0147] Additive (A)-containing composition A-6: Tinuvin 477-DW(N)...aqueous dispersion of acrylic polymer containing a triazine-based ultraviolet absorber (active ingredient (i.e., ultraviolet absorber as additive (A)) 20% by mass, total solids content 40% by mass, manufactured by BASF)

[0148]

[0149] Additive (A)-containing composition A-7: Tinuvin 479-DW(N)...aqueous dispersion of acrylic polymer containing a triazine-based ultraviolet absorber (active ingredient (i.e., ultraviolet absorber as additive (A)) 20% by mass, total solids content 40% by mass, manufactured by BASF)

[0150]

[0151] Additive (A)-containing composition A-8: Tinuvin 9945-DW(N)...an aqueous dispersion of an acrylic polymer containing a benzotriazole-based UV absorber having the following structure (active ingredient (i.e., UV absorber as additive (A)) 45% by mass, total solids content 52% by mass, manufactured by BASF)

[0152]

[0153] Additive (A)-containing composition A-9: UVA-805...aqueous dispersion of a benzotriazole-based polymeric ultraviolet absorber having the following structure (solid content (i.e., ultraviolet absorber as additive (A)) 33% by mass, manufactured by BASF)

[0154]

[0155] Additive (A)-containing composition A-10: HOSTAVIN 3315 DISP...a water dispersion of a benzotriazole-based light stabilizer having the following structure (active ingredient (i.e., light stabilizer as additive (A)) 52% by mass, manufactured by Clariant Chemicals K.K.)

[0156]

[0157] Additive (A)-containing composition A-11: HOSTAVIN 3326 DISP...a water dispersion of a benzotriazole-based light stabilizer having the following structure (active ingredient (i.e., light stabilizer as additive (A)) 52% by mass, manufactured by Clariant Chemicals K.K.)

[0158]

[0159] <Image Recording> Using NPi Form NEXT-IJ<90> (manufactured by Nippon Paper Industries Co., Ltd.) as a recording medium, an image was recorded by the following method.

[0160] (Pretreatment Liquid Application Step) Using a coating bar, a pretreatment liquid (PR-1) (hereinafter also simply referred to as a pretreatment liquid) was applied onto the recording medium in a wet mass of 5.0 g / m. ２ Two seconds after the application of the pretreatment liquid was completed, hot air at a temperature of 100° C. and a velocity of 15 m / sec was blown from a height of 10 cm for two seconds onto the surface of the recording medium on which the pretreatment liquid had been applied, thereby drying the pretreatment liquid.

[0161] (Ink Application Step) Three seconds after the pretreatment liquid had dried, black ink (IK-1), cyan ink (IC-1), magenta ink (IM-1), and yellow ink (IY-1) (hereinafter, these may be referred to as "four color inks") were applied in this order to the surface of the recording medium to which the pretreatment liquid had been applied using a single pass method at a resolution of 1200 dpi × 1200 dpi, and then these inks were dried, thereby recording a four-color mixed image. The four-color mixed image was recorded by applying 1.3 pL each of the four color inks (i.e., black ink (IK-1), cyan ink (IC-1), magenta ink (IM-1), and yellow ink (IY-1)) to a unit area (i.e., one pixel) of 1 / 1200 inch × 1 / 1200 inch (i.e., 1 pixel).

[0162] Furthermore, on another recording medium on which the pretreatment liquid had been dried, a single-color image of each color was recorded in the same manner as for recording the four-color mixed-color image, except that only one of the four ink colors was used. Each single-color image was recorded by applying 3.0 pL of the single-color ink to one pixel.

[0163] Each ink was applied using a 1,200 dpi (dots per inch) / 20 inch wide piezo full line head as an inkjet head. When applying each ink, the drive frequency was 60 kHz and the recording medium transport speed was 1,270 mm / sec.

[0164] The ink was dried by blowing hot air at a temperature of 120°C and a speed of 15 m / sec from a height of 10 cm onto the ink-applied surface of the recording medium for 10 seconds, 2 seconds after the end of application of the ink (or the end of application of the fourth color ink in the case of recording a four-color mixed image).

[0165] (Post-treatment liquid application step) In Tables 2 and 3, the column for the amount of post-treatment liquid applied is 0 g / m ２ In Examples and Comparative Examples other than those in which the column for the amount of post-treatment liquid applied is 0 g / m, the following operation of the post-treatment liquid application step was carried out. ２ In the examples and comparative examples, the following operation of the post-treatment liquid application step was omitted.

[0166] The operation of the post-treatment liquid application step is as follows: For each of the recording media on which a four-color mixed image was recorded and the recording media on which a single-color image of each color was recorded, the post-treatment liquid was applied by flexographic printing to the surface of the recording media on which the pre-treatment liquid and ink had been applied, 3 seconds after the ink had dried, in an amount of 12.0 g / m2 in wet mass. ２ Two seconds after the application of the post-treatment liquid was completed, hot air at a temperature of 100°C and a velocity of 15 m / sec was blown from a height of 10 cm for 10 seconds onto the surface of the recording medium on which the pre-treatment liquid had been applied, thereby drying the post-treatment liquid.

[0167] As a result of the above, a four-color mixed image record containing a recording medium and a four-color mixed image, and four monochrome image records containing a recording medium and a monochrome image of each color (specifically, a black image record containing a recording medium and a monochrome image of black, a cyan image record containing a recording medium and a monochrome image of cyan, a magenta image record containing a recording medium and a monochrome image of magenta, and a yellow image record containing a recording medium and a monochrome image of yellow) were obtained.

[0168] <Evaluation> The following evaluations were carried out using the ink and the image recording material described above. The evaluation results are shown in Tables 2 and 3 below.

[0169] (Lightfastness) The image in the yellow image recording material (i.e., a yellow monochrome image) was measured using a Super Xenon Weather Meter XL75 manufactured by Suga Test Instruments Co., Ltd. at an irradiation illuminance of 180 W / m ２ An accelerated lightfastness test was conducted under conditions of a black panel temperature of 63°C and a humidity of 55% RH. Before the accelerated lightfastness test and 1000 hours after the start of the accelerated lightfastness test, the CIE LAB values ​​(L*, a*, b*) of the image were measured using an X-rite eXact colorimeter manufactured by X-rite under conditions of light source D50 and status -T, and the color difference ΔE was calculated based on the obtained results. The lightfastness of the image was evaluated based on the obtained color difference ΔE according to the following evaluation criteria. In the evaluation criteria below, the most excellent rank for image lightfastness is A.

[0170] -Evaluation criteria for light fastness- A: ΔE≦3 B: 3<ΔE≦6 C: 6<ΔE≦9 D: 9<ΔE

[0171] (Color Density) The density (OD) of the image in the black image recording (i.e., a black monochrome image) was measured using an X-rite eXact colorimeter manufactured by X-Rite Corporation under conditions of light source D50 and status -T. Based on the obtained density (OD), the color density of the image was evaluated according to the following evaluation criteria. In the following evaluation criteria, the rank of the image with the best color density is A.

[0172] -Evaluation criteria for color density- A: OD was 1.15 or more. B: OD was 1.10 or more and less than 1.15. C: OD was 1.00 or more and less than 1.10. D: OD was less than 1.00.

[0173] (Image Quality) Each of 10 observers visually observed the graininess of the image in the four-color mixed image recording (i.e., the four-color mixed image) and rated the image quality according to the following rating criteria. The average of the obtained image quality scores for the 10 observers was calculated. Based on the obtained average, the image quality was evaluated according to the following rating criteria. In the following rating criteria, the most excellent rank for image quality is A.

[0174] - Image quality rating criteria - 5: No image unevenness is observed at all 4: Image unevenness is barely observed 3: Image unevenness is slightly noticeable 2: Image unevenness is noticeable 1: Image unevenness is very noticeable

[0175] - Image quality evaluation criteria - A: The average score for image quality was greater than 4.5 and less than 5.0. B: The average score for image quality was greater than 4.0 and less than 4.5. C: The average score for image quality was greater than 3.5 and less than 4.0. D: The average score for image quality was greater than 3.0 and less than 3.5. E: The average score for image quality was less than 3.0.

[0176] (Feel) The Clark stiffness of the four-color mixed image recorded material was measured using a Clark stiffness tester (fully automatic digital type) manufactured by Kumagai Riki Kogyo Co., Ltd. in accordance with Japanese Industrial Standards JIS P8143:2009, "Paper - Stiffness Test Method - Clark Stiffness Tester Method." Similarly, the Clark stiffness of the recording medium before application of the pretreatment liquid for image recording (hereinafter also referred to as "non-recorded material") was also measured. From these measurement results, the difference from the non-recorded material was calculated according to the following formula: Difference from Non-Recorded Material (%) = ((Clark Stiffness of Four-Color Mixed Image Recorded Material - Clark Stiffness of Non-Recorded Material) / Clark Stiffness of Non-Recorded Material) x 100 Based on the calculated results, the feel of the image recorded material was evaluated according to the following evaluation criteria. In the evaluation criteria below, the most excellent feel of the image recorded material is ranked 5.

[0177] --Evaluation criteria for image quality-- 5: Difference from non-recorded material is 30% or less. 4: Difference from non-recorded material is more than 30% but not more than 60%. 3: Difference from non-recorded material is more than 60% but not more than 100%. 2: Difference from non-recorded material is more than 100% but not more than 150%. 1: Difference from non-recorded material is more than 150%.

[0178] (Ejection Stability) Black ink (IK-1) was continuously ejected for 10 minutes under the following ejection conditions, and the number of nozzles that stopped ejecting (missing nozzles) was counted among 2,048 nozzles. Based on the results obtained, the ejection stability was evaluated according to the following evaluation criteria. In the following evaluation criteria, the most excellent ink ejection stability is ranked 5.

[0179] - Discharge conditions - Head: SAMBA G3L (manufactured by FUJIFILM Dimatix, Inc.) Discharge droplet volume: 1.5 pL (picoliter) Drive frequency: 54 kHz

[0180] -Evaluation criteria for ejection stability- 5: The number of clogged nozzles was 1 or less. 4: The number of clogged nozzles was 2 to 4. 3: The number of clogged nozzles was 5 to 7. 2: The number of clogged nozzles was 7 to 9. 1: The number of clogged nozzles was 10 or more.

[0181]

[0182]

[0183] As shown in Tables 2 and 3, at least the pretreatment liquid contains additive (A), which is at least one selected from the group consisting of a light stabilizer and an ultraviolet absorber, and the total amount of additive (A) applied to the recording medium is 0.05 g / m ２ ~2.00g / m ２ In each of the Examples where the proportion of the amount of additive (A) applied by application of the pretreatment liquid to the total amount of additive (A) applied onto the recording medium (i.e., the "proportion due to application of the pretreatment liquid" in Tables 2 and 3) was 50 mass % to 100 mass %, images excellent in light fastness, color density, and image quality were obtained.

[0184] The results of the comparative examples compared to the examples were as follows: In comparative example 1, in which the pretreatment liquid did not contain additive (A), the lightfastness of the image was reduced. The total amount of additive (A) applied to the recording medium was 0.05 g / m ２ In Comparative Example 2, where the total amount of additive (A) applied to the recording medium was less than 2.00 g / m, the light resistance of the image was reduced. ２ In Comparative Example 3, where the proportion of the amount of additive (A) applied by the application of the pretreatment liquid to the total amount of additive (A) applied to the recording medium was less than 50 mass %, the color density or image quality of the image was reduced.

[0185] Examples 101 and 102 The same operations as in Example 1 were performed, except that the magenta ink (IM-1) was changed to magenta ink (IM-2), the yellow ink (IY-1) was changed to yellow ink (IY-2), and the pretreatment liquid (PR-1) was changed to the following pretreatment liquid (PR-2) or (PR-3). The results are shown in Table 4.

[0186] <Preparation of Pretreatment Solution (PR-2)> The following components were mixed and filtered using a 1 μm filter to obtain a pretreatment solution (PR-2) with a pH of 1.0.

[0187] - Components of Pretreatment Liquid (PR-2) - Malonic acid: 6.80% by mass Malic acid: 5.75% by mass Citric acid: 5.88% by mass Phosphoric acid (85%): 5.05% by mass Diethylene glycol monoethyl ether: 1.20% by mass BYK-093 (defoaming agent, manufactured by BYK Japan KK): 0.01% by mass Sodium dodecylbenzenesulfonate (soft type) (manufactured by Tokyo Chemical Industry Co., Ltd.): 0.50% by mass Benzotriazole: 0.03% by mass Additive (A)-containing composition shown in Table 4: amount corresponding to the content of additive (A) shown in Table 4 Ion-exchanged water: balance amount totaling 100% by mass

[0188] <Preparation of Pretreatment Solution (PR-3)> The following components were mixed and filtered using a 1 μm filter to obtain a pretreatment solution (PR-3) with a pH of 1.0.

[0189] - Components of Pretreatment Liquid (PR-3) - Malonic acid... 0.14 mass% Calcium acetate monohydrate... 6.48 mass% Magnesium acetate tetrahydrate... 10.76 mass% Polyethylene glycol 6,000 (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.)... 2.35 mass% Surfynol 465 (acetylene glycol surfactant, manufactured by Nissin Chemical Industry Co., Ltd.)... 0.20 mass% BYK-024 (defoaming agent, manufactured by BYK Japan KK)... 0.01 mass% Additive (A)-containing composition shown in Table 4... amount corresponding to the content of additive (A) shown in Table 4 Ion-exchanged water... balance amount totaling 100 mass%

[0190]

[0191] As shown in Table 4, in Examples 101 and 102 in which the formulations of the magenta ink, yellow ink, and pretreatment liquid were changed from those in Example 1, similar results to those in Example 1 were obtained.

[0192] The disclosure of Japanese Patent Application No. 2023-125054, filed on July 31, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A method for producing a recording medium comprising the steps of: applying a pretreatment liquid containing water and a coagulant onto a recording medium; and applying, by an inkjet method, an ink containing water and a pigment onto the area of ​​the recording medium onto which the pretreatment liquid has been applied; wherein the pretreatment liquid contains at least one additive (A) selected from the group consisting of a light stabilizer and an ultraviolet absorbing agent; and wherein the total amount of the additive (A) applied onto the recording medium is 0.05 g / m. ２ ~2.00g / m ２ a ratio of an amount of the additive (A) applied by applying the pretreatment liquid to a total amount of the additive (A) applied is 50% by mass to 100% by mass.

2. The image recording method according to claim 1, wherein the light stabilizer comprises a hindered amine compound (I) having a structure represented by the following formula (I): In formula (I), R １ represents a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, or an acyloxy group having 1 to 40 carbon atoms; R ２ ~R ５ Each of R independently represents an alkyl group having 1 to 5 carbon atoms, and two *s each represent a bonding position. ２ and R ３ , and R ４ and R ５ may each be linked via an oxygen atom, a nitrogen atom, or a sulfur atom, or may be linked directly to form a ring.

3. The image recording method according to claim 1 or 2, wherein the ultraviolet absorbing agent comprises at least one selected from the group consisting of benzotriazole compounds and triazine compounds.

4. The image recording method according to claim 1 or 2, wherein the coagulant contains at least one selected from the group consisting of organic acids and organic acid salts.

5. The image recording method according to claim 1 or 2, wherein the ink further contains an additive (A) which is at least one selected from the group consisting of a light stabilizer and an ultraviolet absorber.

6. The image recording method according to claim 1 or 2, further comprising a step of applying a post-treatment liquid containing a liquid component and a resin onto the area on the recording medium to which the ink has been applied, after the step of applying the ink by an inkjet method.

7. The image recording method according to claim 6, wherein the post-treatment liquid further contains an additive (A) which is at least one selected from the group consisting of a light stabilizer and an ultraviolet absorber.