Treatment liquid, recording method, and ink set

Abstract

The present invention provides a treatment liquid, a recording method, and an ink set, which are less likely to generate foreign matter at the time of storage or at the time of introduction into an inkjet recording device. An aqueous treatment liquid, which is a treatment liquid used in recording together with an inkjet ink, the inkjet ink being an aqueous ink composition, the treatment liquid containing a polyvalent metal salt, a resin selected from the group consisting of an acrylic resin and a maleic resin, and a compound selected from the group consisting of an organic acid and an organic amine, the content of the resin being 1 mass% or less with respect to the total mass of the treatment liquid, and the pH of the treatment liquid being 5.5 or more and 7.5 or less.

Description

Technical Field

[0001] This invention relates to processing liquids, recording methods, and ink sets. Background Technology

[0002] Recording methods that suppress bleed spots by using a reaction solution (treatment solution) containing a coagulant that causes ink components to agglomerate to fix the ink adhering to the recording medium in the early stage (reducing its fluidity) are known. For example, Patent Document 1 discloses an inkjet recording method using a reaction solution containing a carboxylic acid or carboxylate, i.e., a reactant, that reacts with the components of the inkjet ink.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2015-217591 Summary of the Invention

[0004] However, even when excellent image quality is achieved using the processing fluid, foreign matter can sometimes form in the processing fluid during storage or when it is introduced into the inkjet recording device. When such foreign matter forms, concerns arise regarding the storage stability of the processing fluid, and additionally, it can cause poor ejection from the inkjet head that ejects the processing fluid.

[0005] One embodiment of the processing liquid of the present invention is a processing liquid used together with inkjet ink for recording, wherein,

[0006] The inkjet ink is a water-based ink composition.

[0007] The treatment solution contains polyvalent metal salts, resins selected from acrylic resins and maleic acid resins, and compounds selected from organic acids and organic amines.

[0008] The resin content is less than 1% by mass relative to the total mass of the treatment solution, the pH of the treatment solution is greater than or equal to 5.5 and less than 7.5, and

[0009] The treatment solution is an aqueous treatment solution.

[0010] One embodiment of the recording method of the present invention is a recording method using the above-described processing liquid and inkjet ink, wherein,

[0011] The recording method includes the following steps:

[0012] The process of attaching the processing liquid to the recording medium, and

[0013] The ink adhesion step involves ejecting the inkjet ink from the inkjet head and attaching it to the recording medium.

[0014] One embodiment of the ink group of the present invention includes the above-described processing liquid and inkjet ink. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an example of an inkjet recording device.

[0016] Figure 2 This is a schematic diagram of the carriage perimeter of an example of an inkjet recording device.

[0017] Figure 3 This is a block diagram of an example of an inkjet recording device.

[0018] Figure 4 This is a schematic diagram of an example of a container for holding treatment fluid.

[0019] Figure Labels

[0020] 1: Inkjet recording unit; 2: Recording head; 3: IR heater; 4: Plate heater; 5: Heater; 6: Cooling fan; 7: Preheater; 8: Ventilation fan; 9: Carriage; 11: Platform; 12: Ink cartridge; 13: Carriage moving mechanism; 14: Transport means; 101: Interface unit; 102: CPU; 103: Memory; 104: Unit control circuit; 111: Transport unit; 112: Carriage unit; 113: Recording head unit; 114: Drying unit; 121: Detector group; 130: Computer; CONT: Control unit; MS: Main scan direction; SS: Sub-scan direction; M: Recording medium Detailed Implementation

[0021] The embodiments of the present invention will be described below. The embodiments described below are examples of the present invention. The present invention is not limited to any of the following embodiments, and includes various modifications implemented without changing the spirit of the invention. It should be noted that not all of the configurations described below are necessarily essential to the present invention.

[0022] 1. Treatment fluid

[0023] The processing liquid in this embodiment is a processing liquid used for recording together with inkjet ink. The inkjet ink used for recording together with the processing liquid is an aqueous ink composition. Furthermore, the processing liquid in this embodiment is an aqueous processing liquid containing a polyvalent metal salt, a resin selected from acrylic resins and maleic acid resins, and a compound selected from organic acids and organic amines. The content of the resin is 1% by mass or less relative to the total mass of the processing liquid, and the pH of the processing liquid is 5.5 or more and 7.5 or less.

[0024] 1.1. Polyvalent metal salts

[0025] The treatment solution contains polyvalent metal salts. Examples of polyvalent metal salts include water-soluble compounds composed of divalent or higher-valent polyvalent metal ions and anions bonded to those ions. Specific examples of polyvalent metal ions include: Ca... 2+ Cu2+ Ni 2+ Mg 2+ Zn 2+ Ba 2+ Divalent metal ions; Al 3+ Fe 3+ Cr 3+ Trivalent metal ions. Examples of anions include: Cl... - I - ,Br - SO4 2- ,ClO 3- NO 3- HCOO - CH3COO - Among these polyvalent metal salts, calcium and magnesium salts are preferred from the viewpoints of stability of the treatment solution and reactivity as a flocculant.

[0026] More specifically, examples include: magnesium salts such as magnesium chloride, magnesium bromide, magnesium acetate, magnesium formate, magnesium lactate, magnesium nitrate, magnesium sulfate, and magnesium thiosulfate; calcium salts such as calcium formate, calcium lactate, calcium bicarbonate, calcium acetate, calcium propionate, calcium benzoate, calcium dihydrogen phosphate, calcium nitrate, and calcium chloride; and aluminum salts such as aluminum nitrate, aluminum chloride, aluminum sulfate, ammonium aluminum sulfate, potassium aluminum sulfate, aluminum formate, aluminum acetate, and aluminum lactate. Polyvalent metal salts can be used alone or in combination with two or more. Furthermore, both anhydrous and hydrated forms can be used.

[0027] When the polyvalent metal salt is a calcium salt, the components contained in the ink have good agglomeration ability, resulting in superior image quality, which is therefore preferred. Furthermore, considering low deliquescence, organic acid polyvalent metal salts are preferred, especially calcium salts of organic acids, which have low deliquescence. This results in superior water resistance, moisture resistance, and scratch resistance of the obtained recordings, making this even more preferable. However, on the other hand, when the polyvalent metal salt is a calcium salt, there is a tendency for foreign matter to be generated in the processing solution. But in the processing solution of this embodiment, by containing a resin selected from acrylic resins and maleic acid resins (described later), the generation of foreign matter can be suppressed even when the polyvalent metal salt is a calcium salt.

[0028] The content of polyvalent metal salts in the processing solution is preferably 0.5% by mass or more and 10% by mass or less relative to the total mass of the processing solution. More preferably, it is 1% by mass or more and 10% by mass or less, more preferably 1.5% by mass or more and 8% by mass or less, and even more preferably 2% by mass or more and 7% by mass or less. When the content of polyvalent metal salts is within this range, the image quality of the image formed using inkjet ink can be improved.

[0029] 1.2. Resin

[0030] The treatment solution contains resins selected from acrylic resins and maleic acid resins.

[0031] Acrylic resins are resins obtained by polymerization using at least acrylic monomers. Acrylic monomers are (meth)acrylic monomers, including acrylic monomers and methacrylic monomers. They can be copolymers of acrylic monomers with other monomers; examples of other monomers include, for instance, vinyl monomers. Resins that are maleic acid resins (described later) are referred to as maleic acid resins.

[0032] Examples of acrylic resins include styrene-acrylic acid copolymers, styrene-acrylic acid-acrylate copolymers, styrene-methacrylic acid copolymers, and styrene-methacrylic acid-acrylate copolymers.

[0033] Maleic acid resins are resins obtained by polymerization using at least maleic acid or maleic acid derivatives. Examples of maleic acid derivatives include maleic anhydride and maleic esters. Copolymers of maleic acid or maleic acid derivatives with other monomers are preferred. Examples of other monomers include vinyl monomers.

[0034] Examples of maleic acid resins include styrene-maleic acid copolymers, acrylate-maleic acid copolymers, and styrene-acrylate-maleic acid copolymers.

[0035] These resins can form salts. It should be noted that in this section, even if maleic acid resins contain acrylic acid and acrylate in their constituent monomers, they are still considered maleic acid resins.

[0036] Partially esterified maleic acid resins tend to react with metal salts, so it is preferable to avoid using such resins or to use them in small quantities.

[0037] The total content of the aforementioned resins in the treatment solution is 1% by mass or less relative to the total mass of the treatment solution. Furthermore, the total content of resins in the treatment solution is preferably 0.01% by mass or more and 1% by mass or less relative to the total mass of the treatment solution, more preferably 0.05% by mass or more and 0.9% by mass or less, even more preferably 0.05% by mass or more and 0.6% by mass or less, and even more preferably 0.1% by mass or more and 0.6% by mass or less.

[0038] By ensuring the total resin content in the treatment solution is within a certain range, the generation of foreign matter in the treatment solution can be sufficiently suppressed even if the components in contact with the treatment solution contain lubricant. This effect is attributed to the use of resin to suppress the precipitation of lubricant from the components and to stabilize the dispersion of any precipitated lubricant.

[0039] On the other hand, in order to prevent the formation of foreign matter caused by resin aggregation, the processing solution of this embodiment contains compounds selected from organic acids and organic amines, which are described later. These compounds act as pH adjusters, thereby adjusting the pH of the processing solution to 5.5 or higher and 7.5 or lower. As a result, resin aggregation and foreign matter formation are also suppressed, thus suppressing both the formation of foreign matter caused by components and the foreign matter formation of resin.

[0040] The resin can be a resin that disperses in an aqueous medium like an emulsion, or it can be a water-soluble resin. However, a water-soluble resin is more preferred. When a water-soluble resin is selected, it is easier to suppress the formation of foreign matter.

[0041] Regarding water-soluble resins, examples include resins that, when diluted 100 times with water to a solid content of 1g, show no detectable particle size peaks when the volume average particle size (D50) is measured using a dynamic light scattering particle size analyzer. Examples of dynamic light scattering particle size analyzers include the Nanotrac Wave II-EX150.

[0042] Furthermore, regarding the resin, a resin that does not react with the calcium formate aqueous solution is preferred. Choosing such a resin reduces the likelihood of foreign matter buildup, even if the components in contact with the treatment solution contain lubricants.

[0043] 1.3. Compounds selected from organic acids and organic amines

[0044] The processing solution in this embodiment contains compounds selected from organic acids and organic amines.

[0045] Examples of organic acids include carboxylic acids. Among carboxylic acids are monocarboxylic acids, dicarboxylic acids, and tricarboxylic acids or more, with dicarboxylic acids being preferred. Organic acids can also be hydroxy acids. Hydroxy acids are organic acids that contain a hydroxyl group within their molecule, and can be monocarboxylic acids, dicarboxylic acids, or tricarboxylic acids or more.

[0046] Examples of organic acids include: monocarboxylic acids such as formic acid, acetic acid, propionic acid, glycolic acid, pyruvic acid, pyrrolidone carboxylic acid, pyrrolic acid, furanoic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, and nicotinic acid; dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, and pyrrolidone carboxylic acid; hydroxycarboxylic acids such as malic acid, ascorbic acid, citric acid, tartaric acid, and lactic acid; or derivatives of these compounds or their salts.

[0047] As organic amines, compounds having an amino group in an alkane skeleton can be listed. In particular, alkanolamines having both a hydroxyl group and an amino group in an alkane skeleton can be listed. Alkanolamines are more preferred as organic amines. The number of hydroxyl groups in the molecule of an alkanolamine is 1 or more, preferably 1 or more and 5 or less, more preferably 2 or more and 3 or less. The number of carbon atoms in the molecule of an organic amine is preferably 1 or more and 20 or less, more preferably 2 or more and 10 or less, and even more preferably 6 or more and 9 or less. The number of carbon atoms in each alkane skeleton is preferably 1 or more and 6 or less, more preferably 2 or more and 4 or less. The number of amino groups in the molecule of an organic amine is 1 or more, preferably 1 or more and 5 or less, more preferably 1 or more and 2 or less.

[0048] As organic amines, there are no particular limitations, and examples include: ethanolamine, N-methylethanolamine, N,N-dimethylethanolamine, N-ethylethanolamine, N-butylethanolamine, N,N-diethylethanolamine, diethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, N-tert-butyldiethanolamine, triethanolamine, isopropanolamine, N,N-dimethylisopropanolamine, N,N-diethylisopropanolamine, diisopropanolamine, etc. Tripropanolamine, triisopropanolamine (TIPA), N,N-dimethylpropanolamine, 2-amino-1-propanol, 2-amino-2-methyl-1-propanol, 5-amino-1-pentanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-hydroxymethyl-1,3-propanediol, 3-amino-1,2-propanediol, 3-methylamino-1,2-propanediol, tripropanolamine and tributanolamine, or derivatives of these compounds, etc. Triethanolamine and triisopropanolamine are preferred, and triisopropanolamine is more preferred. One organic amine may be used alone, or two or more may be used in combination.

[0049] Organic acids and organic amines can be used alone or in combination with two or more. It should be noted that substances whose salts of organic acids are also polyvalent metal salts are considered as substances contained within polyvalent metal salts.

[0050] Relative to the total mass of the treatment liquid, the total amount of compounds selected from organic acids and organic amines is preferably 1% by mass or less, more preferably 0.0001% by mass or more and 0.8% by mass or less, even more preferably 0.0005% to 0.7% by mass, even more preferably 0.001% by mass or more and 0.5% by mass or less, and even more preferably 0.002% by mass or more and 0.2% by mass or less. Furthermore, it is preferably 0.01% to 0.1% by mass, more preferably 0.02% to 0.05% by mass. Alternatively, it is preferably 0.01% by mass or less, more preferably 0.005% by mass or less.

[0051] When the total amount of compounds selected from organic acids and organic amines is within this range, it is easy to adjust the pH of the treatment solution to be above 5.5 and below 7.5. Furthermore, when the total amount of compounds selected from organic acids and organic amines is within this range, it is easy to stabilize the pH at above 5.5 and below 7.5. Considering these aspects, this is superior to using inorganic acids or inorganic bases.

[0052] Furthermore, the compound selected from organic acids and organic amines is more preferably selected from organic acids. Moreover, in this case, the organic acid is further preferably a dicarboxylic acid compound. In this case, the color development and scratch resistance of the image formed using inkjet ink can be improved.

[0053] It should be noted that, depending on the type of polyvalent metal salt, sometimes even without organic acids or organic amines, the pH may be within the specified range. However, in the absence of organic acids or organic amines, the pH is prone to fluctuation during storage. Furthermore, in the treatment solution of this embodiment, since it coexists with resin, the pH is more susceptible to fluctuation, and even minor differences in content due to measurement errors can sometimes lead to significant pH deviations. In the treatment solution of this embodiment, by using organic acids and organic amines, the pH can be easily adjusted to the specified range, and even when coexisting with resin, the pH stability during storage is excellent.

[0054] It should be noted that when using inorganic acids or bases to adjust the pH, there is a tendency for the pH to increase or decrease significantly, making it difficult to adjust to the specified pH, or the pH may fluctuate easily, raising concerns about the formation of foreign matter caused by the resin. When not using organic acids or amines for pH adjustment, especially under conditions such as high-temperature storage, there is a tendency for the pH of the treatment solution to increase or decrease, raising concerns about the formation of foreign matter such as calcium carbonate, or the resin becoming foreignized.

[0055] 1.4. pH of the treatment solution

[0056] The pH of the treatment solution is 5.5 or higher and 7.5 or lower. With the pH of the treatment solution within this range, foreign matter is unlikely to be generated even if the components in contact with the treatment solution contain lubricants. More preferably, the pH of the treatment solution is 5.7 or higher and 7.4 or lower; even more preferably, it is 6.0 or higher and 7.0 or lower; and still more preferably, it is 6.3 or higher and 7.0 or lower.

[0057] When the pH of the processing solution is higher than the above-mentioned range, there is a concern that the polyvalent metal salts may react with CO2 in the air to form carbonates and foreign matter. In particular, if the polyvalent metal salt is a calcium salt, calcium carbonate is easily formed, potentially creating foreign matter. On the other hand, when the pH of the processing solution is lower than the above-mentioned range, the resin is prone to agglomeration, and sometimes the resin forms foreign matter, reducing the storage stability of the processing solution and the stability during inkjet ejection. It should be noted that when the pH of the processing solution is higher than the above-mentioned range, the dispersion or dissolution state of the resin may sometimes become unstable.

[0058] A more preferred range exists between the pH of the processing solution and the pH of the inkjet ink described later. Specifically, the difference between the pH of the processing solution and the pH of the inkjet ink is preferably 3 or less. Furthermore, the difference between the pH of the processing solution and the pH of the inkjet ink is more preferably 2.5 or less, further preferably 2.0 or less, and even more preferably 1.5 or less. The lower limit of the difference is 0 or more. Additionally, the pH of the processing solution is preferably lower than the pH of the ink.

[0059] It should be noted that the pH difference between the processing solution and the inkjet ink is the pH value obtained by subtracting the lower pH value from the higher pH value.

[0060] By setting the pH difference between the processing solution and the inkjet ink within the aforementioned range, the pH of the inkjet ink will not become too high, allowing for a more complete agglomeration (reactivity) of the inkjet ink components, resulting in better scratch resistance and image quality.

[0061] In addition, by setting the pH difference within the above range, the pH of the treatment solution will not become too low, resulting in better storage stability of the treatment solution.

[0062] 1.5. Water

[0063] The processing solution is an aqueous solution and contains water. Examples of water include pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, and distilled water; and ultrapure water, which removes ionic impurities as much as possible. In addition, when water that has been sterilized by ultraviolet irradiation or the addition of hydrogen peroxide is used, the growth of bacteria and fungi can be inhibited during long-term storage of inkjet ink.

[0064] The water content relative to the total mass of the treatment liquid is preferably 40% by mass or more, more preferably 45% by mass or more, more preferably 50% by mass or more, and particularly preferably 60% by mass or more. Furthermore, there is no particular upper limit on the water content; for example, relative to the total mass of the treatment liquid, it is preferably 98% by mass or less, more preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0065] 1.6. Other ingredients

[0066] The treatment solution may contain the following components.

[0067] 1.6.1. Water-soluble low molecular weight compounds

[0068] The treatment solution may contain water-soluble low-molecular-weight compounds. This category excludes colorants, polyvalent metal salts, organic acids, and organic amines. Water-soluble low-molecular-weight compounds are primarily organic solvents and solid compounds.

[0069] "Water solubility" refers to a solubility of more than 10g in 100g of water at 20℃. Examples of water-soluble low-molecular-weight compounds include compounds that are liquids at room temperature and compounds that are solids at room temperature. By including water-soluble low-molecular-weight compounds in the treatment solution, its clogging recovery properties, preservation stability, and image quality can be improved.

[0070] The method for determining the solubility of water-soluble low-molecular-weight compounds is as follows: First, at 20°C, a specified amount of the water-soluble low-molecular-weight compound is mixed into 100g of water and stirred for 30 minutes. After stirring, for compounds that are liquid at room temperature, if no phase separation or island-like structure occurs, they are considered dissolved. Furthermore, for compounds that are solid at room temperature, if no dissolved residue remains, they are considered dissolved.

[0071] The solubility is defined as the largest specified amount among those that, when mixed with a specified amount of a compound in 100g of water, would be considered dissolved. Compounds with a solubility greater than 10g are defined as water-soluble low-molecular-weight compounds. It should be noted that water-soluble low-molecular-weight compounds can be compounds that are completely miscible with water or compounds that are miscible with water.

[0072] In this specification, "completely mixable with water" means that the compound and water are mutually soluble, i.e., the solubility of the compound in 100g of water at 20°C is infinitely high. Conversely, "mixable with water" means that the compound and water have finite solubility, i.e., the solubility of the compound in 100g of water at 20°C is greater than 10g. It should be noted that the solubility of water-soluble low-molecular-weight compounds is greater than 10g, but there is no upper limit; it can be infinite. The solubility is preferably 11g or more, more preferably 50g or more.

[0073] The water-soluble low-molecular-weight compound preferably has a molecular weight of 500 or less, based on its weight-average molecular weight. More preferably, it has a molecular weight of 400 or less, and even more preferably, it has a molecular weight of 300 or less. Furthermore, the treatment liquid preferably contains a compound with a standard boiling point of 150°C or higher and 350°C or lower, more preferably 150°C or higher and 300°C or lower, as the water-soluble low-molecular-weight compound. Additionally, regarding the water-soluble low-molecular-weight compound, it is preferable to include a compound with a melting point of 90°C or lower. Moreover, it is preferable to include a compound with a melting point of 80°C or lower. Furthermore, the melting point is preferably -70°C or higher.

[0074] Examples of water-soluble low-molecular-weight compounds with a solubility greater than 10g in 100g of water at 20°C include: resin-soluble substances, polyols, and glycol ethers. Examples of resin-soluble substances include: amides, sulfur-containing solvents, and cyclic ethers. Among these, resin-soluble substances, polyols, and glycol ethers are preferred.

[0075] Further preferred compounds include: any one of amides, sulfur-containing solvents, and cyclic ethers with a standard boiling point of 150°C or higher and 300°C or lower; and any one of polyols and glycol ethers with a standard boiling point of 150°C or higher and 250°C or lower.

[0076] Relative to the total mass of the treatment liquid d, it is preferable to contain 40% or less of water-soluble low molecular weight compound, more preferably 1% or more of water-soluble low molecular weight compound, even more preferably 5% or more and 30% or less of water-soluble low molecular weight compound, and even more preferably 10% or more and 25% or less of water-soluble low molecular weight compound.

[0077] <Resin Dissolved Substances>

[0078] Examples of water-soluble low-molecular-weight compounds with a solubility greater than 10g in 100g of water at 20°C include resin-dissolving substances that are any of the following: amides, sulfur-containing solvents, and cyclic ethers. Preferably, the compound contains any of the following resin-dissolving substances that have a standard boiling point of 150°C or higher and 300°C or lower. It should be noted that resin-dissolving substances refer to organic compounds that have the function of dissolving resin and improving scratch resistance, but are not limited to this function.

[0079] Examples of the aforementioned amides include: 2-pyrrolidone (2P), 2-piperidinone, ε-caprolactam (CPL), N-methyl-ε-caprolactam, N-cyclohexyl-2-pyrrolidone, N-methylpyrrolidone, N-ethylpyrrolidone, N-butylpyrrolidone, 5-methyl-2-pyrrolidone, β-propiolactam, ω-heptyllactam, and other cyclic amides (lactams); N,N-dimethylacetylacetamide, N,N-diethylacetylacetamide, N-methylacetylacetamide, N,N-dimethylisobutyramide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropionamide, 3-methoxy-N,N-dimethylpropionamide (DMPA), 3-n-butoxy-N,N-dimethylpropionamide, 3-methoxy-N,N-di-dimethylpropionamide, etc. Ethylpropionamide, 3-methoxy-N,N-methylethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, 3-ethoxy-N,N-diethylpropionamide, 3-ethoxy-N,N-methylethylpropionamide, 3-n-butoxy-N,N-diethylpropionamide, 3-n-butoxy-N,N-methylethylpropionamide, 3-n-propoxy-N,N-dimethylpropionamide, 3-n-propoxy-N,N-diethylpropionamide, 3-n-propoxy-N,N-methylethylpropionamide, 3-isopropoxy-N,N-dimethylpropionamide, 3-isopropoxy-N,N-diethylpropionamide, 3-isopropoxy-N,N-methylethylpropionamide, 3-tert-butoxy-N,N-dimethylpropionamide, 3-tert-butoxy-N,N-diethylpropionamide, 3-tert-butoxy-N,N-methylethylpropionamide, and other chain amides. Among them, any one of 2-pyrrolidone (2P), ε-caprolactam (CPL), and 3-methoxy-N,N-dimethylpropionamide (DMPA) is preferred, as it tends to improve the preservation stability of the ink.

[0080] Examples of sulfur-containing solvents include: 3-methylcyclobutane sulfone, sulfolane, ethyl isopropyl sulfone, ethyl methyl sulfone, dimethyl sulfone, dimethyl sulfoxide (DMSO), diethyl sulfoxide, tetramethylene sulfoxide, and methyl phenyl sulfoxide. Among these, dimethyl sulfoxide (DMSO) is preferred, as it tends to improve the storage stability of inks.

[0081] Examples of the aforementioned cyclic ethers include: isosorbide dimethyl ether, 3-methyl-3-oxetane methanol, 3-ethyl-3-oxetane methanol (DMHD), 2-hydroxymethyloxetane, tetrahydrofurfuryl alcohol, acetone glycerol, glyceryl formal, 1,4-dioxane-2,3-diol, and dihydro-L-glucanone. Among these, 3-ethyl-3-oxetane methanol (DMHD) is preferred, as it tends to improve the preservation stability of inks.

[0082] Among these, resin-soluble substances with a standard boiling point of 150°C or higher and 300°C or lower, and which are amides, tend to have better storage stability and are therefore preferred. Furthermore, the resin-soluble substance is preferably a compound with a melting point of 80°C or lower. When the melting point is within the above range, it tends to have excellent clogging recovery properties.

[0083] Relative to the total mass of the treatment solution, the treatment solution preferably contains 20% by mass or less of a resin-dissolving substance selected from amides, sulfur-containing solvents, and cyclic ethers as a water-soluble low-molecular-weight compound, more preferably 15% by mass or less, even more preferably 10% by mass or less, and particularly preferably 5% by mass or less. Furthermore, the lower limit is 0% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more.

[0084] Furthermore, the content of resin-soluble substances with a standard boiling point of 150°C or higher and 300°C or lower, and which are any of the following: amides, sulfur-containing solvents, or cyclic ethers, can be set within the aforementioned range. When the content of these resin-soluble substances is within the aforementioned range, the resin's solubility in the treatment solution becomes good, tending to exhibit better storage stability and scratch resistance. On the other hand, when the content of these resin-soluble substances exceeds the aforementioned range, storage stability sometimes decreases. This is presumably because the resin becomes less soluble due to the relatively reduced water content in the treatment solution.

[0085] <Polyols and glycol ethers>

[0086] The treatment solution may contain any one of the following compounds: polyols or glycol ethers, as a water-soluble low-molecular-weight compound other than the resin-dissolving substances mentioned above. In particular, it is preferable to contain any one of the following compounds: polyols or glycol ethers, with a standard boiling point of 150°C or higher and 250°C or lower.

[0087] (Polyols)

[0088] Polyols are preferably diols or compounds obtained by intermolecular condensation of diols with hydroxyl groups. In this case, it is a compound having two hydroxyl groups. Alternatively, examples of polyols include compounds obtained by intermolecular condensation of diols with hydroxyl groups in which hydrogen atoms are replaced by hydroxyl groups. In this case, it is a compound having three or more hydroxyl groups.

[0089] The number of carbon atoms in the diol unit of a polyol or a compound obtained by intermolecular condensation of diols with hydroxyl groups is preferably 2 or more and 10 or less, more preferably 3 or more and 8 or less. Furthermore, the number of carbon atoms in the molecule of the polyol is preferably 2 or more and 15 or less, more preferably 3 or more and 10 or less. Additionally, the standard boiling point of the polyol is preferably 150°C or higher and 250°C or lower.

[0090] Examples of polyols with a standard boiling point above 150°C and below 250°C include: ethylene glycol (standard boiling point 198°C, miscible with water), diethylene glycol (standard boiling point 244°C, completely miscible with water), 1,2-propanediol (propylene glycol) (standard boiling point 188°C, completely miscible with water), dipropylene glycol (standard boiling point 227°C, completely miscible with water), 1,2-butanediol (standard boiling point 193°C, miscible with water), 1,2-pentanediol (standard boiling point 210°C, miscible with water), 1,2-hexanediol (standard boiling point 224°C, completely miscible with water), 1,3-propanediol (standard boiling point 214°C, completely miscible with water), 1,4-butanediol (standard boiling point 228°C, completely miscible with water), 2,3-butanediol (standard boiling point 177°C, miscible with water), 1, 3-Butanediol (standard boiling point 207℃, completely miscible with water), 3-methyl-1,3-butanediol (standard boiling point 203℃, completely miscible with water), 2-methyl-1,3-propanediol (standard boiling point 214℃, completely miscible with water), 2,2-dimethyl-1,3-propanediol (standard boiling point 208℃, solubility 83 [g / 100g water]), 2-methylpentane-2,4-diol (standard boiling point 197℃, completely miscible with water), 2,5-dimethyl-2,5-hexanediol (standard boiling point 218℃, solubility 14 [g / 100g water]), 1,5-pentanediol (standard boiling point 242℃, miscible with water), 3-methyl-1,5-pentanediol (standard boiling point 250℃, completely miscible with water), 1,6-hexanediol (standard boiling point 250℃, miscible with water), etc. As a type of polyol, polyols with 10 or fewer carbon atoms are more preferred.

[0091] Among polyols, alkyldiols with a standard boiling point of 150°C or higher and 250°C or lower and with 10 or fewer carbon atoms are more preferred, and alkyldiols with a standard boiling point of 150°C or higher and 250°C or lower and with 6 or fewer carbon atoms are even more preferred. Examples of such alkyldiols include, for instance, ethylene glycol, propylene glycol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, etc., which are 1,2-alkyldiols; and 1,3-propanediol, 1,3-butanediol, etc.

[0092] Relative to the total mass of the treatment solution, the treatment solution preferably contains 1% to 5% by mass of alkanediols with a standard boiling point of 150°C or higher and 250°C or lower and with 6 or fewer carbon atoms as water-soluble low-molecular-weight compounds.

[0093] (Diol ethers)

[0094] Glycol ethers are compounds obtained by etherifying one or more hydroxyl groups of a glycol. Preferably, mono- or di-ethers of alkylene glycols are preferred. Alkyl ethers are preferred as the etherified ethers. The alkyl group of the alkylene glycol constituting the glycol ether preferably has 1 or more and 5 or less carbon atoms, more preferably 2 or more and 4 or less. Glycol ethers are also more preferably those with a standard boiling point of 150°C or higher and 250°C or lower.

[0095] Examples of glycol ethers include: ethylene glycol monomethyl ether (completely miscible with water), ethylene glycol monoethyl ether (miscible with water), ethylene glycol monoisopropyl ether (solubility 100 g / 100 g water), ethylene glycol monopropyl ether (miscible with water), ethylene glycol monoisobutyl ether (solubility 75.5 g / 100 g water), ethylene glycol monotert-butyl ether (miscible with water), ethylene glycol monobutyl ether (solubility 100 g / 100 g water), and diethylene glycol monomethyl ether (completely miscible with water). (Mixed), diethylene glycol monoethyl ether (completely mixed with water), diethylene glycol monoisopropyl ether (mixed with water), diethylene glycol monoisobutyl ether (completely mixed with water), diethylene glycol monobutyl ether (completely mixed with water), triethylene glycol monomethyl ether (completely mixed with water), triethylene glycol monoethyl ether (completely mixed with water), triethylene glycol monobutyl ether (mixed with water), tetraethylene glycol monomethyl ether (mixed with water), propylene glycol monomethyl ether (mixed with water), propylene glycol monoethyl ether (completely mixed with water) Alkylene glycol monoalkyl ethers, including propylene glycol monopropyl ether (mixable with water), dipropylene glycol monomethyl ether (completely mixable with water), dipropylene glycol monopropyl ether (solubility 19 g / 100 g water), tripropylene glycol monomethyl ether (completely mixable with water), 1,3-propanediol monomethyl ether (3-methoxy-1-propanol) (completely mixable with water), and 1,3-butanediol-3-monomethyl ether (3-methoxy-1-butanol) (mixable with water); and ethylene glycol dimethyl ether (completely mixable with water). Alkylene glycol dimethyl ethers (glyme) include: diethylene glycol dimethyl ether (completely mixed with water), diethylene glycol methyl ethyl ether (completely mixed with water), diethylene glycol diethyl ether (completely mixed with water), triethylene glycol dimethyl ether (completely mixed with water), tetraethylene glycol dimethyl ether (completely mixed with water), dipropylene glycol dimethyl ether (solubility 52.6 [g / 100g water]), and tripropylene glycol dimethyl ether (solubility 23.6 [g / 100g water]).

[0096] Furthermore, among the aforementioned glycol ethers, diethers tend to more readily dissolve or swell the resin in the processing solution compared to monoethers, making them more preferable in improving the scratch resistance of the resulting image. On the other hand, monoethers are preferred in terms of excellent wetting and spreading properties of the processing solution.

[0097] Relative to the total mass of the treatment solution, the treatment solution preferably contains 30% by mass or less of any one of polyols or glycol ethers as a water-soluble low-molecular-weight compound, more preferably 25% by mass or less. Furthermore, as a lower limit, it is 0% by mass or more relative to the total mass of the treatment solution, preferably 10% by mass or more, more preferably 15% by mass or more.

[0098] In addition, it is preferable to set the content of any one of the polyols and glycol ethers with a standard boiling point of 150 to 250°C within the above range.

[0099] When these water-soluble low-molecular-weight compounds are present within the aforementioned range, the resin tends to exhibit better solubility and superior storage stability.

[0100] <Other Compounds>

[0101] The treatment solution may contain other substances as needed.

[0102] 1.6.2. Surfactants

[0103] The treatment solution may contain surfactants. There are no particular restrictions on the surfactants used, but examples include: acetylenic diol surfactants, fluorinated surfactants, and organosilicon surfactants.

[0104] As a acetylenic diol surfactant, there are no particular limitations, but examples include: Sufynol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, DF110D (all of these are trade names, manufactured by Air Products, Japan Co., Ltd.); OLFINE B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP.4001, EXP.4036, EXP.4051, AF-103, AF-104, AK-02, SK-14, AE-3 (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.); ACETYLENOL E00, E00P, E40, E100 (all trade names, manufactured by Kawaken Fine Chemicals Co., Ltd.).

[0105] As a fluorinated surfactant, fluorinated modified polymers are preferred. For example, BYK-340 (trade name, manufactured by BYK Chemicals Japan Co., Ltd.) can be cited.

[0106] There are no particular limitations on the type of organosilicon surfactant, but polysiloxane compounds are preferred. Furthermore, there are no particular limitations on the type of polysiloxane compound, but examples include polyether-modified organosilicon compounds. Commercially available examples of this polyether-modified organosiloxane include: BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (trade names, manufactured by BYK Chemicals Japan Co., Ltd.); KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (trade names, manufactured by Shin-Etsu Chemical Industry Co., Ltd.); SILFACES AG503A, SILFACE SAG014 (the above are product names, manufactured by Nisshin Chemical Industry Co., Ltd.), etc.

[0107] The surfactants mentioned above can be used alone or in combination with two or more.

[0108] When a surfactant is present, the surfactant content is preferably set to 0.1% by mass or more and 1.5% by mass or less relative to the total mass of the treatment liquid.

[0109] Alternatively, it is preferable to set the content of the organosilicon surfactant or fluorinated surfactant in the above-mentioned surfactant within the range described above. More preferably, the content of the organosilicon surfactant in the above-mentioned surfactant can also be set within the range described above.

[0110] Typically, adding silicone surfactants to the processing solution tends to further improve image quality, but scratch resistance and defoaming properties tend to deteriorate. However, in the processing solution of this embodiment, even a small amount within the above-mentioned range results in excellent image quality and good scratch resistance.

[0111] 1.6.3. Other additives

[0112] The treatment solution can contain various additives such as chelating agents, rust inhibitors, mildew inhibitors, antioxidants, anti-reduction agents, and evaporation promoters, as needed.

[0113] (Regarding monohydric alcohols with a standard boiling point above 280°C)

[0114] The treatment solution preferably does not contain more than 3% by mass of polyols with a standard boiling point higher than 280°C as water-soluble low-molecular-weight compounds relative to the total mass of the treatment solution. Moreover, it is more preferable that it does not contain more than 1% by mass of polyols with a standard boiling point higher than 280°C, and even more preferably that it does not contain more than 0.5% by mass of polyols with a standard boiling point higher than 280°C.

[0115] In this case, the processing solution may or may not contain polyols with a standard boiling point higher than 280°C, and if it does contain polyols with a standard boiling point higher than 280°C, the content should be below the aforementioned level. When the content of polyols with a standard boiling point higher than 280°C is within the aforementioned range, the drying properties of the processing solution are not significantly reduced. As a result, even when recording on low-absorbent or non-absorbent recording media, the tendency for image fixation to decrease can be suppressed. Furthermore, even if the temperature of the recording medium during heat drying is relatively low, sufficient drying can be achieved. Examples of such polyols with a standard boiling point higher than 280°C include, for example, glycerol (standard boiling point 290°C), excluding alkylolamines such as triisopropanolamine.

[0116] 1.7. Preparation and Properties of the Treatment Solution

[0117] The treatment solution is obtained by mixing the above components in any order and removing impurities by filtration or other methods as needed. As a method for mixing the components, it is preferable to add the materials sequentially to a container equipped with a stirring device such as a mechanical stirrer or magnetic stirrer and mix them by stirring. As a filtration method, centrifugal filtration, filter filtration, etc., can be performed as needed.

[0118] From the viewpoint of further improving the image quality of inkjet inks, the surface tension (static surface tension) of the processing liquid at 20°C is preferably 18 mN / m or more and 40 mN / m, more preferably 20 mN / m or more and 35 mN / m or less, and even more preferably 22 mN / m or more and 33 mN / m or less. It should be noted that the surface tension can be measured, for example, by using an automatic surface tension meter CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.) to confirm the surface tension when the platinum plate is wetted with the processing liquid at 20°C.

[0119] From the same perspective, the viscosity of the treatment liquid at 20°C is preferably 3 mPa·s or more and 10 mPa·s or less, more preferably 3 mPa·s or more and 8 mPa·s or less. It should be noted that, for example, the viscosity at 20°C can be measured using a viscoelasticity tester MCR-300 (trade name, manufactured by Pysica).

[0120] 1.8. Applications of the processing solution and ink group

[0121] Processing fluid is used for recording along with inkjet ink. The processing fluid can be pre-applied to the medium onto which the inkjet ink will be applied. Alternatively, the processing fluid, like the inkjet ink, can be ejected from the printhead for recording. This method helps to control the amount of processing fluid used.

[0122] Furthermore, the processing fluid can be combined with inkjet ink to form an ink kit. That is, an ink kit includes both processing fluid and inkjet ink. An ink kit is a set of inks and processing fluid used for recording in a package format.

[0123] According to this ink group, even if the components in contact with the processing liquid contain lubricant, foreign matter is less likely to be generated. Moreover, it can improve the image quality of images formed by inkjet ink.

[0124] 2. Recording Method

[0125] The recording method using a processing liquid and inkjet ink will be described below. The recording method of this embodiment is a recording method using the above-described processing liquid and the inkjet ink described later, wherein the recording method includes: a processing liquid adhesion step of adhering the processing liquid to the recording medium, and an ink adhesion step of ejecting inkjet ink from the inkjet head and adhering it to the recording medium.

[0126] 2.1. Inkjet ink

[0127] Inkjet inks used with the processing liquid are water-based ink compositions. Inkjet inks may contain the following components.

[0128] 2.1.1. Pigments

[0129] Inkjet inks may contain colorants. Colorants can be at least one of pigments and dyes.

[0130] <Pigment>

[0131] Pigments can be either inorganic or organic. Using pigments as colorants can sometimes improve the lightfastness of inkjet inks, which is preferred.

[0132] As an inorganic pigment, it can use carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; iron oxide and titanium oxide.

[0133] Organic pigments include: insoluble azo pigments, condensed azo pigments, azo lakes, chelated azo pigments, and other azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and violet ketone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindolinone pigments, isoindolineone pigments, and quinoline ketone pigments; dye chelates (e.g., basic dye chelates, acid dye chelates, etc.); lakes (basic dye lakes, acid dye lakes); nitro pigments, nitroso pigments, aniline black, and daylight fluorescent pigments.

[0134] More specifically, carbon black used as black inks can be listed as follows: No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B, etc. (all manufactured by Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (all manufactured by Carbon Columbia Corporation), etc.

[0135] Examples of pigments used as white inks include: CI Pigment White 6, 18, and 21.

[0136] Examples of pigments used as yellow inks include: CI Pigment Yellow 1, CI Pigment Yellow 2, CI Pigment Yellow 3, CI Pigment Yellow 4, CI Pigment Yellow 5, CI Pigment Yellow 6, CI Pigment Yellow 7, CI Pigment Yellow 10, CI Pigment Yellow 11, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 16, CI Pigment Yellow 17, CI Pigment Yellow 24, CI Pigment Yellow 34, CI Pigment Yellow 35, CI Pigment Yellow 37, CI Pigment Yellow 53, CI Pigment Yellow 55, CI Pigment Yellow 65, CI Pigment Yellow 73, CI Pigment Yellow 74, CI Pigment Yellow 75, CI Pigment Yellow 81, CI Pigment Yellow 83, CI Pigment Yellow 93, CI Pigment Yellow 84, CI Pigment Yellow 85, CI Pigment Yellow 95, CI Pigment Yellow 86, CI Pigment Yellow 87, CI Pigment Yellow 88, CI Pigment Yellow 89 ... Pigment Yellow 94, CI Pigment Yellow 95, CI Pigment Yellow 97, CI Pigment Yellow 98, CI Pigment Yellow 99, CI Pigment Yellow 108, CI Pigment Yellow 109, CI Pigment Yellow 110, CI Pigment Yellow 113, CI Pigment Yellow 114, CI Pigment Yellow 117, CI Pigment Yellow 120, CI Pigment Yellow 124, CI Pigment Yellow 128, CI Pigment Yellow 129, CI Pigment Yellow 133, CI Pigment Yellow 138, CI Pigment Yellow 139, CI Pigment Yellow 147, CI Pigment Yellow 151, CI Pigment Yellow 153, CI Pigment Yellow 154, CI Pigment Yellow 155, CI Pigment Yellow 167, CI Pigment Yellow 172, CI Pigment Yellow 180.

[0137] As pigments used in red inks for artworks, the following can be listed: CI Pigment Red 1, CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 4, CI Pigment Red 5, CI Pigment Red 6, CI Pigment Red 7, CI Pigment Red 8, CI Pigment Red 9, CI Pigment Red 10, CI Pigment Red 11, CI Pigment Red 12, CI Pigment Red 14, CI Pigment Red 15, CI Pigment Red 16, CI Pigment Red 17, CI Pigment Red 18, CI Pigment Red 19, CI Pigment Red 21, CI Pigment Red 22, CI Pigment Red 23, CI Pigment Red 30, CI Pigment Red 31, CI Pigment Red 32, CI Pigment Red 37, CI Pigment Red 38, CI Pigment Red 40, CI Pigment Red 41, CI Pigment Red 42, CI Pigment Red 48 (Ca), CI Pigment Red 48 (Mn), CI Pigment Red 57 (Ca), CI Pigment Red 57:1, CI Pigment Red 8 8. CI Pigment Red 112, CI Pigment Red 114, CI Pigment Red 122, CI Pigment Red 123, CI Pigment Red 144, CI Pigment Red 146, CI Pigment Red 149, CI Pigment Red 150, CI Pigment Red 166, CI Pigment Red 168, CI Pigment Red 170, CI Pigment Red 171, CI Pigment Red 175, CI Pigment Red 176, CI Pigment Red 177, CI Pigment Red 178, CI Pigment Red 179, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 187, CI Pigment Red 202, CI Pigment Red 209, CI Pigment Red 219, CI Pigment Red 224, CI Pigment Red 245, or CI Pigment Violet 19, CI Pigment Violet 23, CI Pigment Violet 32, CI Pigment Violet 33, CI Pigment Violet 36, CI Pigment Violet 38, CI Pigment Violet 43, CI Pigment Violet 50. Solid solutions of multiple pigments mentioned above may also be used.

[0138] As pigments used as cyan inks, the following can be listed: CI Pigment Blue 1, CI Pigment Blue 2, CI Pigment Blue 3, CI Pigment Blue 15, CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4, CI Pigment Blue 16, CI Pigment Blue 18, CI Pigment Blue 22, CI Pigment Blue 25, CI Pigment Blue 60, CI Pigment Blue 65, CI Pigment Blue 66, CI Vapor Blue 4, CI Vapor Blue 60.

[0139] In addition, other than magenta, cyan, and yellow, the following pigments can be listed: CI Pigment Green 7, CI Pigment Green 10, CI Pigment Brown 3, CI Pigment Brown 5, CI Pigment Brown 25, CI Pigment Brown 26, CI Pigment Orange 1, CI Pigment Orange 2, CI Pigment Orange 5, CI Pigment Orange 7, CI Pigment Orange 13, CI Pigment Orange 14, CI Pigment Orange 15, CI Pigment Orange 16, CI Pigment Orange 24, CI Pigment Orange 34, CI Pigment Orange 36, CI Pigment Orange 38, CI Pigment Orange 40, CI Pigment Orange 43, and CI Pigment Orange 63.

[0140] The above-mentioned pigments can be used alone or in combination with two or more.

[0141] When pigments are used in inkjet inks, the average particle size is preferably 300 nm or less, more preferably 50 to 200 nm. When the average particle size is within the above range, the inkjet ink exhibits superior reliability in terms of ejection stability and dispersion stability, and tends to produce images with excellent image quality. Here, the average particle size in this specification is measured by dynamic light scattering.

[0142] [Pigment Dispersion]

[0143] The pigments described above can exist in a dispersed state in inkjet ink, i.e., in the form of a pigment dispersion. Here, the term "pigment dispersion" in this specification means that it includes pigment dispersion liquids and pigment slurries (low-viscosity aqueous dispersions).

[0144] Examples of pigment dispersions include, but are not limited to, self-dispersible pigments, polymer-dispersible pigments, and pigments coated with polymers.

[0145] (Self-dispersing pigment)

[0146] Self-dispersible pigments refer to pigments that can be dispersed or dissolved in aqueous media without a dispersant. Here, "dispersed or dissolved in aqueous media without a dispersant" means that the pigment exists stably in the aqueous media due to the hydrophilic groups on its surface, even without the use of a dispersant. Therefore, there is almost no foaming caused by reduced defoaming properties due to the dispersant, making it easy to prepare inks with excellent spray stability. Furthermore, since the significant increase in viscosity caused by the dispersant is suppressed, more pigment can be contained, and the printing density can be significantly increased, making it easy to handle.

[0147] The hydrophilic group is preferably one or more hydrophilic groups selected from the group consisting of -OM, -COOM, -CO-, -SO3M, -SO2M, -SO2NH2, -RSO2M, -PO3HM, -PO3M2, -SO2NHCOR, -NH3, and -NR3.

[0148] It should be noted that in these chemical formulas, M represents a hydrogen atom, an alkali metal, ammonium, a phenyl group that may have substituents, or an organic ammonium group, and R represents an alkyl group with 1 to 12 carbon atoms or a naphthyl group that may have substituents. Furthermore, M and R are chosen independently of each other.

[0149] Self-dispersible pigments are manufactured, for example, by physically or chemically treating the pigment to bond (graft) the aforementioned hydrophilic groups onto the pigment surface. Examples of such physical treatments include vacuum plasma treatment. Examples of such chemical treatments include wet oxidation methods using an oxidizing agent in water, and methods that bond carboxyl groups via phenyl groups by bonding p-aminobenzoic acid to the pigment surface.

[0150] (Polymer Dispersion Pigments)

[0151] Polymer-dispersed pigments are pigments that can be dispersed by polymer dispersion. The polymer used in polymer-dispersed pigments is not limited to polymers such as those used for pigment dispersion. For example, the glass transition temperature (Tg) of the dispersion polymer is preferably 80°C or lower, more preferably 75°C or lower. When the Tg is 80°C or lower, good colorfastness of the ink can sometimes be achieved.

[0152] Furthermore, the weight-average molecular weight of the aforementioned polymer, as determined by gel permeation chromatography (GPC), is preferably 10,000 or more and 200,000 or less. This sometimes results in better ink storage stability. Here, the weight-average molecular weight (Mw) in this specification can be determined using gel permeation chromatography (GPC) on an L7100 system manufactured by Hitachi, Ltd., based on the weight-average molecular weight converted from polystyrene.

[0153] As the aforementioned polymer, a polymer obtained by copolymerization of (meth)acrylate and (meth)acrylic acid, comprising 70% or more of its constituent components, is preferred because it tends to have superior ink fixation and gloss. A polymer obtained by polymerization of monomer components comprising at least 70% or more of an alkyl ester of (meth)acrylic acid having 1 to 24 carbon atoms and a cyclic alkyl ester of (meth)acrylic acid having 3 to 24 carbon atoms. Specific examples of this monomeric component include, but are not limited to, the following substances: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, tert-butylcyclohexyl methacrylate, lauryl methacrylate, isobornyl methacrylate, cetyl methacrylate, stearyl methacrylate, isostearyl methacrylate, tetramethylpiperidinyl methacrylate, tetrahydrodicyclopentadienyl methacrylate, dihydrodicyclopentadienyl methacrylate, dihydrodicyclopentadienyl methacrylate, and behenyl methacrylate. In addition, hydroxyl (meth)acrylates, urethane (meth)acrylates, and epoxy (meth)acrylates, which have hydroxyl groups, such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and diethylene glycol (meth)acrylate, can also be used as monomer components for other polymerizations.

[0154] It should be noted that, in this specification, the term (meth)acrylic acid refers to at least one of acrylic acid and methacrylic acid. The term (meth)acrylate refers to at least one of acrylate and methacrylate.

[0155] (Pyramid-coated pigment)

[0156] Furthermore, among the aforementioned polymer-dispersed pigments, it is preferable to use pigments coated with polymers, i.e., microencapsulated pigments, because they tend to have excellent ink fixation, gloss, and color reproduction properties.

[0157] The polymer-coated pigment is obtained through a phase inversion emulsification method. Specifically, the polymer is dissolved in organic solvents such as methanol, ethanol, isopropanol, n-butanol, acetone, methyl ethyl ketone, and dibutyl ether. A pigment is added to the resulting solution, followed by the addition of a neutralizing agent and water, and the mixture is then kneaded and dispersed to prepare an oil-in-water dispersion. The organic solvent is then removed from the resulting dispersion, yielding the polymer-coated pigment as an aqueous dispersion. The kneading and dispersion processes can be performed using, for example, ball mills, roller mills, bead mills, high-pressure homogenizers, and high-speed stirring dispersers.

[0158] Preferred neutralizing agents include tertiary amines such as ethylamine and trimethylamine, lithium hydroxide, sodium hydroxide, potassium hydroxide, and ammonia. The pH of the resulting aqueous dispersion is preferably 6–10.

[0159] From the perspective of ensuring stable dispersion of the pigment, polymers with a weight-average molecular weight of about 10,000 to 150,000 as determined by GPC are preferred as the polymer for coating pigments.

[0160] <Dyes>

[0161] There are no particular restrictions on the types of dyes used; acid dyes, direct dyes, reactive dyes, and basic dyes can all be used. Examples of such dyes include: CI Acid Yellow 17, 23, 42, 44, 79, 142; CI Acid Red 52, 80, 82, 249, 254, 289; CI Acid Blue 9, 45, 249; CI Acid Black 1, 2, 24, 94; CI Food Black 1, 2; CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 1 44, 173; CI Direct Red 1, 4, 9, 80, 81, 225, 227; CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202; CI Direct Black 19, 38, 51, 71, 154, 168, 171, 195; CI Reactive Red 14, 32, 55, 79, 141, 249; CI Reactive Black 3, 4, 35.

[0162] The dyes mentioned above can be used alone or in combination of two or more.

[0163] The content of pigment (solids) relative to the total mass of the inkjet ink is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more. Furthermore, the content of pigment (solids) relative to the total mass of the inkjet ink is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less. Alternatively, it is preferably 5% by mass or more. When the pigment content is within the above range, the storage stability is sometimes superior.

[0164] 2.1.2. Water

[0165] The inkjet ink is a water-based inkjet ink (water-based ink) and contains water. A "water-based" composition refers to a composition in which water is one of the main solvents. Regarding water, as described in the section on processing liquids above, further explanation is omitted.

[0166] 2.1.3. Other ingredients

[0167] (Water-soluble low molecular weight compounds)

[0168] Inkjet inks may contain water-soluble low-molecular-weight compounds. The presence of these compounds in inkjet inks facilitates excellent ink clogging recovery, preservation stability, and image quality. Specific examples of water-soluble low-molecular-weight compounds are the same as described in the section on processing liquids above, and therefore, their description is omitted. The content of the water-soluble low-molecular-weight compound in the ink is preferably 0.5% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less.

[0169] (surfactant)

[0170] Inkjet inks may contain surfactants. Specific examples of surfactants are the same as those described in the section on processing solutions above, and therefore are omitted.

[0171] (resin)

[0172] Inkjet inks may contain resins. These resins can be formulated as water-soluble resins or emulsions of resin particles. Such resins sometimes function as so-called fixing resins, which improve the adhesion and scratch resistance of pigment ink components to the recording medium. Emulsions of resin particles are preferred as the resin.

[0173] Examples of resins include, for instance, polyurethane resins, acrylic resins, fluorene resins, polyolefin resins, rosin-modified resins, terpene resins, polyester resins, polyamide resins, epoxy resins, vinyl chloride resins, ethylene-vinyl acetate resins, vinyl acetate resins, butadiene resins, styrene resins, crosslinked acrylic resins, crosslinked styrene resins, phenylguanidine resins, phenolic resins, silicone resins, epoxy resins, paraffin resins, and fluorinated resins. These resins are mostly processed in the form of emulsions, but they can also be in powder form. Furthermore, one type of resin can be used alone, or two or more can be used in combination.

[0174] Polyurethane resins are a general term for resins containing urethane bonds. Among polyurethane resins, those containing ether bonds in the main chain (in addition to urethane bonds), polyester resins containing ester bonds in the main chain, and polycarbonate resins containing carbonate bonds in the main chain can be used. As a polyurethane resin, commercially available products can be used, such as: Superflex 210, 460, 460s, 840, E-4000 (trade name, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.), RESAMINE D-1060, D-2020, D-4080, D-4200, D-6300, D-6455 (trade name, manufactured by Dai-Nippon Seika Co., Ltd.), TAKELAC WS-6020, WS-6021, W-512-A-6 (trade name, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), Sancure2710 (trade name, manufactured by LUBRIZOL Co., Ltd.), PERMARIN UA-150 (trade name, manufactured by Sanyo Chemical Co., Ltd.), etc.

[0175] Acrylic resins are a general term for polymers obtained by polymerizing acrylic monomers such as (meth)acrylic acid and (meth)acrylates as at least one component. Examples include resins obtained from acrylic monomers and copolymers of acrylic monomers with other monomers. Examples include acrylic-vinyl resins, which are copolymers of acrylic monomers and vinyl monomers. Furthermore, examples include copolymers with vinyl monomers such as styrene. Acrylamide, acrylonitrile, etc., can also be used as acrylic monomers.

[0176] As for resin emulsions using acrylic resins as raw materials, commercially available products can be used, such as: Mowinyl 952B, 718A (trade name, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.); Nipol LX852, LX874 (trade name, manufactured by Zeon Corporation); POLYSOL AT860 (manufactured by Showa Denko Co., Ltd.); VONCOAT AN-1190S, YG-651, AC-501, AN-1170, 4001 (trade name, manufactured by DIC Corporation, acrylic resin emulsion), etc.

[0177] It should be noted that, as described above, acrylic resins can be styrene-acrylic resins. Furthermore, in this specification, the term (meth)acrylic acid refers to at least one of acrylic acid and methacrylic acid.

[0178] Styrene-acrylic resins are copolymers obtained from styrene monomers and acrylic monomers. Examples include: styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylate copolymers, styrene-α-methylstyrene-acrylic acid copolymers, and styrene-α-methylstyrene-acrylic acid-acrylate copolymers. As a styrene-acrylic resin, commercially available products can be used, such as: Joncryl 62J, 7100, 390, 711, 511, 7001, 631, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, 7610 (trade names, manufactured by BASF); Mowinyl 966A, 975N (trade names, manufactured by Nippon Synthetic Chemicals Co., Ltd.), etc.

[0179] Vinyl chloride resins can be vinyl chloride-vinyl acetate copolymers.

[0180] Polyolefin resins are resins that contain olefins such as ethylene, propylene, and butene in their structural backbone. Well-known polyolefin resins can be appropriately selected and used. Commercially available products can be used as polyolefin resins, such as Arrowbase CB-1200 and CD-1200 (trade name, manufactured by Unitika Co., Ltd.).

[0181] In addition, the resin can be supplied in the form of an emulsion. Examples of commercially available resin emulsions include: Microgel E-1002, E-5002 (manufactured by Nippon Paint Co., Ltd., trade name: styrene-acrylic resin emulsion); VONCOAT AN-1190S, YG-651, AC-501, AN-1170, 4001, 5454 (manufactured by DIC Corporation, trade name: styrene-acrylic resin emulsion); POLYSOL AM-710, AM-920, AM-2300, AP-4735, AT-860, PSASE-4210E (acrylic resin emulsion); POLYSOL AP-7020 (styrene-acrylic resin emulsion); POLYSOL SH-502 (vinyl acetate resin emulsion); POLYSOL AD-13, AD-2, AD-10, AD-96, AD-17, AD-70 (ethylene-vinyl acetate resin emulsion); POLYSOL PSASE-6010 (ethylene-vinyl acetate resin emulsion) (manufactured by Showa Denko Corporation, trade name); POLYSOL SAE1014 (trade name, styrene-acrylic resin emulsion, manufactured by Zeon Corporation); SAIVINOL SK-200 (trade name, acrylic resin emulsion, manufactured by SAIDEN Chemical Co., Ltd.); AE-120A (manufactured by JSR Corporation, trade name, acrylic resin emulsion); AE373D (manufactured by E-TEC Corporation, trade name, carboxyl-modified styrene-acrylic resin emulsion); SEIKADYNE 1900W (manufactured by Dainisei Chemical Co., Ltd., trade name, ethylene-vinyl acetate resin emulsion); Vinyblan 2682 (acrylic resin emulsion), Vinyblan 2886 (vinyl acetate-acrylic resin emulsion), Vinyblan 5202 (acetic acid-acrylic resin emulsion) (manufactured by Nissin Chemical Industry Co., Ltd., trade name); Vinyblan 700, 2586 (manufactured by Nissin Chemical Industry Co., Ltd.); Elitel KA-5071S, KT-8803, KT-9204, KT-8701, KT-8904, KT-0507 (manufactured by Unitika Co., Ltd., trade name, polyester resin emulsion); HI-TEC SN-2002 (manufactured by Toho Chemical Co., Ltd., trade name, polyester resin emulsion); TAKELAC W-6020, W-635, W-6061, W-605, W-635, W-6021 (manufactured by Mitsui Chemicals Polyurethane Co., Ltd., trade name, polyurethane resin emulsion); Superflex 870, 800, 150, 420, 460, 470, 610, 620, 700 (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., trade name: polyurethane resin emulsion);PERMARIN UA-150 (manufactured by Sanyo Chemical Industries, Ltd., polyurethane resin emulsion); Sancure 2710 (manufactured by LUBRIZOL Corporation, Japan, polyurethane resin emulsion); NeoRez R-9660, R-9637, R-940 (manufactured by Kusumoto Chemical Co., Ltd., polyurethane resin emulsion); ADEKA BONTIGHTER HUX-380, 290K (manufactured by ADEKA Corporation, polyurethane resin emulsion); Mowinyl 966A, Mowinyl 7320 (manufactured by Nippon Synthetic Chemicals Co., Ltd.); Joncryl 7100, 390, 711, 511, 7001, 631, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, 7610 (all manufactured by BASF); NK Binder R-5HN (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.); HYDRAN WLS-210 (non-crosslinked polyurethane: manufactured by DIC Corporation); Joncryl 7610 (manufactured by BASF), etc.

[0182] Among these resins, acrylic resins are preferred, and styrene-acrylic resins are more preferred. Such resins tend to have superior scratch resistance.

[0183] Furthermore, the glass transition temperature (Tg) of the resin is preferably 60°C or higher, more preferably 70°C or higher, even more preferably 80°C or higher, and particularly preferably 90°C or higher. On the other hand, it is preferably 120°C or lower, more preferably 115°C or lower, even more preferably 110°C or lower, and particularly preferably 105°C or lower. When the glass transition temperature (Tg) of the resin is within the above range, the depth of streaks can sometimes be further reduced, resulting in better scratch resistance.

[0184] It should be noted that the glass transition temperature (Tg) of the resin can be confirmed by conventional methods such as differential scanning calorimetry (DSC).

[0185] The resin content, in terms of solids, is preferably 0.1% by mass or more and 20% by mass or less relative to the total mass of the inkjet ink, more preferably 1.0% by mass or more and 15.0% by mass or less, even more preferably 2.0% by mass or more and 10.0% by mass or less, and particularly preferably 3.0% by mass or more and 8.0% by mass or less.

[0186] (wax)

[0187] Inkjet inks may contain wax. Examples of waxes include waxes that are solvents in the ink or waxes dispersed in the form of microparticles such as emulsions. By using such waxes, there is a tendency to obtain recorded media with superior scratch resistance. In particular, there is a tendency to improve scratch resistance by means of the uneven distribution of the ink film on the surface of the recording medium, i.e., at the interface between the air and the ink film.

[0188] There are no particular limitations on such waxes, and examples include: ester waxes of higher fatty acids and higher monohydric or dihydric alcohols, paraffin waxes, microcrystalline waxes, or polyolefin waxes, or mixtures thereof.

[0189] Examples of polyolefin waxes include waxes or copolymers made from olefins such as ethylene, propylene, and butene, or their derivatives. Specifically, these include polyethylene waxes, polypropylene waxes, and polybutene waxes. Commercially available polyolefin waxes can be used, including: Nopcote PEM17 (trade name, manufactured by San Nopco Co., Ltd.), ChemipearlW4005 (trade name, manufactured by Mitsui Chemicals Co., Ltd.), AQUACER515, AQUACER593 (trade names, manufactured by BYK Chemicals Japan Co., Ltd.), and HI-TEC E-6500 (manufactured by Toho Chemical Co., Ltd., a polyethylene wax).

[0190] When wax is present, its content relative to the total mass of the inkjet ink is preferably 0.1% by mass or more and 5% by mass or less, more preferably 0.2% by mass or more and 4% by mass or less, and even more preferably 0.3% by mass or more and 3% by mass or less. When the wax content is within the above range, it tends to have improved scratch resistance, maintain low ink viscosity, excellent ejection stability, and excellent clogging recovery, and is therefore preferred.

[0191] (Other substances)

[0192] Inkjet inks can contain various additives such as chelating agents, rust inhibitors, mildew inhibitors, antioxidants, anti-reduction agents, and evaporation accelerators, depending on the requirements.

[0193] 2.1.4. Preparation and Properties of Inkjet Inks

[0194] Inkjet ink is obtained by mixing the above components in any order and removing impurities by filtration or other methods as needed. As a method for mixing the components, it is preferable to add the materials sequentially to a container equipped with a stirring device such as a mechanical stirrer or magnetic stirrer and then mix them by stirring. As a filtration method, centrifugal filtration, filter filtration, etc., can be performed as needed.

[0195] From the viewpoint of balancing image quality and the reliability of inks used for inkjet recording, the surface tension (static surface tension) of the inkjet ink at 20°C is preferably 18 mN / m or more and 40 mN / m or less, more preferably 20 mN / m or more and 35 mN / m or less, and even more preferably 22 mN / m or more and 33 mN / m or less. It should be noted that the surface tension can be measured, for example, by using an automatic surface tension meter CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.) to confirm the surface tension when the ink wets a platinum plate at 20°C.

[0196] From the same perspective, the viscosity of the ink at 20°C is preferably 3 mPa·s or higher and 10 mPa·s or lower, more preferably 3 mPa·s or higher and 8 mPa·s or lower. It should be noted that the viscosity can be measured, for example, using a viscoelasticity tester MCR-300 (trade name, manufactured by Pysica) at 20°C.

[0197] 2.2. Recording Method

[0198] The recording method is a recording method that uses the above-mentioned processing liquid and inkjet ink for recording. The recording method includes: a processing liquid adhesion step of adhering the processing liquid to the recording medium, and an ink adhesion step of ejecting inkjet ink from the inkjet head and adhering it to the recording medium.

[0199] 2.2.1. Recording medium

[0200] Recording media can be either recording media with an ink-absorbing recording surface or recording media without an ink-absorbing recording surface. Therefore, there are no particular limitations on the recording media, and examples include: liquid absorbent media such as paper, film, and cloth; liquid low absorbent recording media such as printing paper; and liquid non-absorbent recording media such as metals, glass, and polymers.

[0201] Recording media with low or no liquid absorption refers to recording media that have the property of completely or almost no absorption of ink. Quantitatively, recording media with low or no liquid absorption refers to those that, in the Bristol process, absorb ink from the start of contact for 30 msec. 1 / 2 The water absorption rate up to this point is 10 mL / m 2The following is a description of the recording medium. The Bristol method is the most common method for determining liquid absorption over a short period of time and is also adopted by the Japan Pulp Technology Association (JAPAN TAPPI). The detailed test method is described in Standard No. 51 "Paper and Paperboard - Liquid Absorption Test Method - Bristol Method" of the "JAPAN TAPPI Pulp Test Methods 2000 Edition". In contrast, liquid-absorbent recording media refers to recording media that are not classified as non-absorbent or low-absorbent. It should be noted that in this specification, low-absorbent and non-absorbent liquid properties are sometimes simply referred to as low-absorbent and non-absorbent.

[0202] Examples of non-absorbent recording media include: recording media with plastic coated on a paper substrate; recording media with a plastic film adhered to a paper substrate; and plastic films without an absorbent layer (receiving layer). Examples of plastics mentioned here include: polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

[0203] Furthermore, examples of recording media with low liquid absorption include recording media having a coating with low liquid absorption on its surface. For example, recording media known as coated paper. Examples of low-absorption recording media with paper as the substrate include printing papers such as art paper, coated paper, and matte paper; in the case of a plastic film substrate, examples include recording media with polymers coated on the surface of polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc.; and recording media coated with particles of silica, titanium dioxide, etc., and a binder.

[0204] Liquid-absorbing recording media can also be used as recording media. Liquid-absorbing recording media refers to the aforementioned "from the start of contact to 30 msec in the Bristol method". 1 / 2 The water absorption rate is greater than 10 mL / m 2 "Recording medium".

[0205] Examples of liquid-absorbing recording media include recording media that become liquid-absorbing recording media by providing a liquid-absorbing containment layer on the surface of the recording medium. Examples include inkjet paper (inkjet-specific paper). Examples of liquid-absorbing containment layers include layers composed of liquid-absorbing resin, liquid-absorbing inorganic particles, etc.

[0206] Examples of liquid-absorbing recording media include those whose substrate is itself liquid-absorbing. Examples include cloth containing fibers and paper made from pulp. Examples of paper include ordinary paper, thick paper, and backing paper. Examples of backing paper include backing paper made from kraft pulp, waste paper, etc.

[0207] The recording method of this embodiment exhibits significantly better scratch resistance and image quality when applied to low-absorbency or non-absorbency recording media, as the images formed by inkjet inks are presented.

[0208] 2.2.2. Treatment liquid adhesion steps

[0209] The processing liquid adhesion step in the recording method of this embodiment is a step of adhering the above-mentioned processing liquid to the recording medium.

[0210] The treatment liquid adhesion step can be performed simultaneously with the ink adhesion step described later, or it can be performed before or after the ink adhesion step described later.

[0211] Examples of methods for adhering the processing liquid include: impregnation coating, in which the recording medium is immersed in the processing liquid; roller coating, in which the processing liquid is adhered using brushes, rollers, doctor blades, roller coaters, etc.; spray coating, in which the processing liquid is sprayed using a spraying device, etc.; and inkjet coating, in which the processing liquid is adhered using an inkjet method. Among these, the inkjet method is preferred.

[0212] Relative to the amount of inkjet ink adhered in the ink adhesion step, the amount of processing liquid adhered in the processing liquid adhesion step of the recording medium in the area where the ink and processing liquid overlap is preferably 5% by mass or more, more preferably 7% by mass or more, and particularly preferably 9% by mass or more. On the other hand, relative to the amount of inkjet ink adhered in the ink adhesion step, the amount of processing liquid adhered is preferably 25% by mass or less, more preferably 21% by mass or less, further preferably 17% by mass or less, and particularly preferably 13% by mass or less. When the amount of processing liquid adhered is within the above range, there is a tendency to preferably achieve both image quality and scratch resistance.

[0213] Furthermore, the amount of processing liquid adhering to the area of ​​the recording medium where ink and processing liquid overlap is preferably 0.1 mg / inch. 2 Above and 5mg / inch 2 Furthermore, it is preferable to set the amount of processing liquid adhering to the area in the recording medium where the ink and processing liquid overlap and adhere most heavily to the range described above.

[0214] 2.2.3. Ink Adhesion Steps

[0215] The ink adhesion step in the recording method of this embodiment is a step of spraying the above-mentioned inkjet ink using an inkjet method and adhering it to the recording medium.

[0216] In the ink adhesion step, the amount of ink composition adhered to per unit area of ​​the recording medium in the area where ink is adhered is preferably 3 mg / inch. 2 The above, preferably 5 mg / inch 2 The above is further preferred to be 10 mg / inch. 2 The above. The preferred adhesion amount of the ink composition per unit area of ​​recording media is 20 mg / inch. 2 The following is more preferably 18 mg / inch. 2 The following is a further preferred value: 16 mg / inch 2 Hereinafter, it is preferable to set the amount of ink composition adhering per unit area of ​​the recording medium in the region where the ink adheres to the recording medium is the largest, i.e., the maximum amount of ink adhering, to the range described above.

[0217] 2.2.4. Serial Recording Method

[0218] The recording method of this embodiment is preferably a serial recording method that records by multiple main scans within the same scanning area. That is, the processing liquid adhesion step and the ink adhesion step are preferably performed using a serial recording method.

[0219] For example, the treatment liquid adhesion step and the ink adhesion step can use the methods described later. Figure 1 and Figure 2 The inkjet recording apparatus shown, equipped with a serial recording head (recording head 2), is implemented using a serial recording method. In this serial recording method, the processing liquid attachment step and the ink attachment step are performed by multiple main scans in which the ink composition and processing liquid are attached to the same scanning area of ​​the recording medium M while the relative positions of the recording head 2 and the recording medium M are changed along the main scanning direction MS, and by multiple sub-scans in which the relative positions of the carriage 9 and the recording medium M are changed along the sub-scanning direction SS, which is orthogonal to the main scanning direction MS. The number of main scans is preferably 2 to 20, more preferably 3 to 15, and even more preferably 4 to 10.

[0220] In this configuration, the nozzle surface (not shown) of the recording head 2 has multiple nozzle rows along the main scanning direction MS, wherein the multiple nozzles are arranged along the sub-scanning direction SS. The multiple nozzle rows are preferably configured such that at least a portion overlaps when projected along the main scanning direction MS, and each nozzle row is capable of ejecting a processing liquid or ink composition. This facilitates the ejection of the processing liquid or ink composition in the same main scan and its adhesion to the same position in the sub-scanning direction of the recording medium.

[0221] The recording method of this embodiment records by multiple master scans. When multiple master scans are performed in the same scanning area, the amount of ink droplets adhering in a single master scan is small. In this case, the ink droplets adhere discretely to the recording medium, thus reducing the chance of contact between adjacent ink droplets. As a result, the ink filling ability on the recording medium is poor, making it easier to produce dark and light stripes that resemble veins in the recorded image. That is, serial recording methods are more prone to producing dark and light stripes. However, according to the recording method of this embodiment, since the above-described processing liquid is used, even in such a serial recording method, there is a tendency to effectively reduce dark and light stripes and to have excellent preservation stability of the processing liquid.

[0222] It should be noted that performing multiple main scans within the same scanning area refers to scanning again in an area that has already undergone one scan. For example, if the distance of a sub-scan is shorter than the length of the sub-scanning direction of the ink-ejecting nozzle array, a second scan is performed within the scanning area of ​​the first main scan. For instance, if the distance of a sub-scan is one-quarter of the length of the sub-scanning direction of the ink-ejecting nozzle array, then four main scans are performed within the same scanning area. In this case, the number of main scans is referred to as 4.

[0223] It should be noted that the recording method of this embodiment can also be performed using a line recording head to record in a single scan. In other words, even with a line recording method, the effects of the processing liquid, ink group, and recording method of this embodiment can be fully achieved. In this case, ridge-like streaks may sometimes occur along the scanning direction; according to this embodiment, these ridge-like streaks can be reduced.

[0224] 2.2.5. Primary heating step

[0225] The recording method of this embodiment may include a heating step of heating the inkjet ink attached to the recording medium.

[0226] The primary heating step is a step of drying the ink adhered to the recording medium by heating it in an early stage. The primary heating step is a heating step used to dry at least a portion of the solvent component of the ink adhered to the recording medium to a degree that at least reduces the flow of the ink. The primary heating step can be performed by allowing the ink to adhere to the heated recording medium, or by heating it in an early stage after adhesion. In the primary heating step, it is preferable to begin heating the ink droplets that fall onto the recording medium within 0.5 seconds of the droplets falling. Alternatively, the primary heating step can also be performed on the adhering processing liquid, just like with the ink.

[0227] The preferred heating steps are an IR heater, microwave radiation, a plate heater, and hot air blown onto the recording medium by a fan.

[0228] The heating step can be performed at least at any stage, either before, simultaneously with, or in the early stage after the treatment liquid adhesion step and the ink adhesion step, preferably simultaneously. This heating sequence allows for the treatment liquid adhesion step and the ink adhesion step to be performed.

[0229] When the ink is applied to a heated recording medium, the heating temperature of the first heating step is the surface temperature of the recording medium at the time of ink application. If heating is performed in the early stages after ink application, the heating temperature of the first heating step is the surface temperature of the recording medium at the time of heating. Furthermore, the heating temperature of the first heating step is the maximum temperature reached during the first heating step.

[0230] The heating temperature of the first heating step, measured by the surface temperature of the recording surface of the heated recording medium, is preferably 28°C or higher, more preferably 30°C or higher, even more preferably 32°C or higher, and particularly preferably 34°C or higher. Furthermore, the heating temperature of the first heating step, measured by the surface temperature of the heated recording surface of the recording medium, is preferably 50°C or lower, more preferably 45°C or lower, and even more preferably 40°C or lower. When the heating temperature of the first heating step is within the above range, it tends to effectively reduce shallow and deep banding, and to obtain good image quality (coagulated banding) and good clogging recovery.

[0231] 2.2.6. Post-heating step

[0232] The recording method of this embodiment may include a post-heating step of heating the recording medium after the above-described processing liquid adhesion step and ink adhesion step.

[0233] The post-heating step is a heating step that heats the material sufficiently to the point where recording is complete and the recording medium is usable. The post-heating step is used to thoroughly dry the solvent components of the ink or processing liquid and to heat the resins contained in the ink to flatten the ink film. The post-heating step preferably begins more than 0.5 seconds after the ink and processing liquid have adhered to the recording medium. For example, it is preferable to begin heating a recording area more than 0.5 seconds after the ink and processing liquid have completely adhered to a certain recording area of ​​the recording medium. Furthermore, it is preferable that the temperature preferred in the primary heating step is different from the temperature preferred in the post-heating step.

[0234] For example, when using an inkjet recording apparatus, the heating of the recording medium in the post-heating step can be performed using an appropriate heating method. Furthermore, the heating method is not limited to that found in inkjet recording apparatuses; any appropriate heating method can be used. In this case, the surface temperature of the recording medium is preferably 60°C or higher, more preferably 70°C or higher, even more preferably 80°C or higher, and particularly preferably 85°C or higher. Furthermore, the surface temperature of the recording medium after being heated in the post-heating step is preferably 120°C or lower, more preferably 110°C or lower, even more preferably 100°C or lower, and particularly preferably 95°C or lower. According to the recording method of this embodiment, even with a surface temperature of the recording medium within the above-mentioned range, the ink can be sufficiently dried, resulting in a recording with excellent scratch resistance.

[0235] 2.3. Inkjet Recording Device

[0236] An example of an inkjet recording apparatus suitable for each step of the recording method of this embodiment will be described with reference to the accompanying drawings.

[0237] <Summary of Device Structure>

[0238] Figure 1 This is a schematic cross-sectional view of an inkjet recording device. Figure 2 To show Figure 1 A perspective view of an example of the configuration of the carriage periphery of an inkjet recording device 1. Figure 1 , Figure 2 As shown, the inkjet recording device 1 includes: a recording head 2, an IR heater 3, a plate heater 4, a heater 5, a cooling fan 6, a preheater 7, an exhaust fan 8, a carriage 9, a platform 11, a carriage moving mechanism 13, a transport means 14, and a control unit CONT. The inkjet recording device 1... Figure 2 The control unit CONT shown controls the overall operation of the inkjet recording device 1.

[0239] <The Structure of the Recording Head>

[0240] The recording head 2 is configured to record on the recording medium M by ejecting ink from the nozzle of the recording head 2 and allowing it to adhere. The same operation can also be performed on the processing liquid. Figure 1 and Figure 2 The recording head 2 shown is a serial recording head, which applies ink or processing liquid to the recording medium M by scanning it multiple times along the main scanning direction relative to the recording medium M. The recording head 2 is mounted on... Figure 2The recording head 2 scans multiple times relative to the recording medium M along the main scanning direction by operating the carriage moving mechanism 13, which moves the carriage 9 along the width direction of the recording medium M. The width direction of the medium is the main scanning direction of the recording head 2. The scanning along the main scanning direction is also called the main scan.

[0241] Furthermore, here, the main scanning direction is the direction in which the carriage 9 carrying the recording head 2 moves. Figure 1 In this context, the main scanning direction is orthogonal to the secondary scanning direction, which is the transport direction of the recording medium M, indicated by arrow SS. Figure 2 In this diagram, the width direction of the recording medium M, represented by S1-S2, is the main scanning direction MS, and the direction represented by T1→T2 is the sub-scanning direction SS. It should be noted that in a single scan, scanning is performed along either the main scanning direction (arrow S1 or arrow S2). Furthermore, recording of the recording medium M is achieved by repeatedly performing the main scan of the recording head 2 and the sub-scans used for transporting the recording medium M.

[0242] The ink cartridge 12, which supplies ink or processing fluid to the recording head 2, comprises multiple independent ink cartridges. The ink cartridge 12 is detachably mounted on the carriage 9 that houses the recording head 2. Different types of inkjet ink or processing fluid can be filled into the multiple ink cartridges, and the inkjet ink or processing fluid can be supplied from the ink cartridge 12 to each nozzle. It should be noted that... Figure 1 and Figure 2 The image shows an example of mounting the ink cartridge 12 on the carriage 9, but it is not limited to this. It can also be mounted on a location other than the carriage 9 and supplied to each nozzle through a supply pipe not shown.

[0243] The ejection of the recording head 2 can be performed using conventionally known methods. Here, a method of ejecting droplets by means of vibration of a piezoelectric element is used, that is, an ejection method in which ink droplets are formed by mechanical deformation of the piezoelectric element.

[0244] <Primary heating mechanism>

[0245] The inkjet recording apparatus 1 can have a primary heating mechanism that heats the recording medium M when ink or processing liquid is ejected from the recording head 2 and adheres to the recording medium. The primary heating mechanism can be conductive, air-blown, or radiative. Conductive heating transfers heat from a component in contact with the recording medium to the recording medium. Examples include plate heaters. Air-blown heating dries the ink by blowing room-temperature or hot air onto the recording medium. Examples include blowers. Radiative heating heats the recording medium by radiating heat-generating rays onto it. Examples include IR radiation. Additionally, although not shown, a heater similar to the plate heater can be provided downstream of the plate heater 4 in the SS direction. These primary heating mechanisms can be used individually or in combination. For example, an IR heater 3 and a plate heater 4 can be used as a primary heating mechanism.

[0246] It should be noted that when using the IR heater 3, the recording medium M can be heated radiatively from the recording head 2 side using infrared radiation. Therefore, the recording head 2 can also be heated simultaneously, but compared to cases where heating is performed from the back of the recording medium M, such as with a plate heater 4, the temperature can be raised without being affected by the thickness of the recording medium M. It should also be noted that various fans (e.g., ventilation fan 8) can be used to bring hot air or air at the same temperature as the environment into contact with the recording medium M to dry the ink on the recording medium M.

[0247] The plate heater 4 heats the recording medium M across the stage plate 11 at a position opposite the recording head 2. The plate heater 4 heats the recording medium M by conduction and is used as needed in inkjet recording methods.

[0248] In addition, the inkjet recording apparatus 1 may have a preheater 7 that preheats the recording medium M before applying ink or processing liquid to the recording medium M.

[0249] <Post-heating mechanism>

[0250] It may have a post-heating mechanism that heats the recording medium after the processing liquid adhesion step and the ink adhesion step to dry and fix the ink, etc.

[0251] The heater 5 used in the post-heating mechanism dries and cures the ink and other substances adhering to the recording medium M. By heating the recording medium M on which the image is recorded, the heater 5 causes the water and other substances contained in the ink or processing liquid to evaporate and disperse more rapidly, and an ink film is formed by the resin contained in the ink. In this way, the ink film is firmly fixed or adhered to the recording medium M, exhibiting excellent film-forming properties, and enabling the acquisition of excellent high-quality images in a short time.

[0252] <Other Components>

[0253] The inkjet recording device 1 may include a cooling fan 6. After the ink or the like recorded on the recording medium M is dried, the cooling fan 6 is used to cool the ink on the recording medium M, thereby forming a well-adhesive ink coating on the recording medium M.

[0254] Below the carriage 9 are a platform 11 supporting the recording medium M, a carriage moving mechanism 13 that moves the carriage 9 relative to the recording medium M, and a transport means 14 that serves as a roller for transporting the recording medium M along the sub-scanning direction. The operation of the carriage moving mechanism 13 and the transport means 14 is controlled by the control unit CONT.

[0255] <Electrical Control>

[0256] Figure 3 This is a functional block diagram of the inkjet recording device 1. The control unit CONT is a control unit for controlling the inkjet recording device 1. The interface unit 101 (I / F) is a unit for receiving / transmitting data between the computer 130 (COMP) and the inkjet recording device 1. The CPU 102 is an arithmetic processing unit for controlling the inkjet recording device 1 as a whole. The memory 103 (MEM) is a unit for storing programs, working areas, etc., in the CPU 102. The CPU 102 controls each unit via the unit control circuit 104 (UCTRL). It should be noted that the detector group 121 (DS) monitors the condition within the inkjet recording device 1, and based on its detection results, the control unit CONT controls each unit.

[0257] The transport unit 111 (CONVU) is a unit that controls the sub-scanning (transportation) of inkjet recording. Specifically, it controls the transport direction and speed of the recording medium M. More specifically, it controls the transport direction and speed of the recording medium M by controlling the rotation direction and speed of the motor-driven transport roller.

[0258] The carriage unit 112 (CARU) is a unit that controls the main scan (track) of inkjet recording; specifically, it is a unit that reciprocates the recording head 2 along the main scan direction. The carriage unit 112 has a carriage 9 that carries the recording head 2 and a carriage moving mechanism 13 for reciprocating the carriage 9.

[0259] The recording head unit 113 (HU) is a unit that controls the amount of ink or processing liquid ejected from the nozzles of the recording head 2. For example, if the nozzles of the recording head 2 are nozzles driven by piezoelectric elements, the operation of the piezoelectric elements of each nozzle is controlled. The recording head unit 113 controls the timing of ink and processing liquid adhesion, the ink or processing liquid droplet size, etc. Furthermore, the amount of ink or processing liquid adhered in each scan is controlled by combining the control of the carriage unit 112 and the recording head unit 113.

[0260] The drying unit 114(DU) controls the temperature of various heaters, including IR heater 3, preheater 7, plate heater 4, and heater 5.

[0261] The inkjet recording apparatus 1 described above alternately performs operations of moving the carriage 9 carrying the recording head 2 along the main scanning direction and transport operations (sub-scanning). During each pass, the control unit CONT controls the carriage unit 112 to move the recording head 2 along the main scanning direction, while simultaneously controlling the recording head unit 113 to eject droplets of ink or processing fluid from the predetermined nozzle orifice of the recording head 2, causing the droplets to adhere to the recording medium M. Furthermore, the control unit CONT controls the transport unit 111 to transport the recording medium M along the transport direction with a predetermined transport amount (transfer amount) during the transport operation.

[0262] In the inkjet recording apparatus 1, a recording area covered with a large number of droplets is slowly transported by repeatedly performing main scans (tracks) and sub-scans (transport operations). Furthermore, a heater 5 dries the droplets adhering to the recording medium M, thereby completing the image. The completed recording can then be wound into a roll using a winding mechanism or transported using a flat belt mechanism.

[0263] The components of the recording apparatus used in the recording method that come into contact with the processing fluid may contain a lubricant. Examples of lubricants include fatty acid lubricants, hydrocarbon lubricants, and higher alcohol lubricants.

[0264] Examples of fatty acid-based lubricants include: fatty acids, fatty acid salts, and fatty acid derivatives. Examples of fatty acid derivatives include: fatty acid amides and fatty acid esters.

[0265] Regarding components of the recording device that come into contact with the processing fluid, examples include: the packaging film constituting the ink pack containing the processing fluid, the inner surface of the ink cartridge, the ink supply tube, and the flow path of the processing fluid within the inkjet head. These components (the materials constituting the components) contain lubricant. The presence of lubricant imparts lubricity to the components, resulting in excellent strength, scratch resistance, and demolding properties during component molding, which is preferable.

[0266] On the other hand, in cases where lubricants are present, foreign matter may sometimes be generated in the processing fluid due to the lubricant. Even in such cases, when using the processing fluid of this embodiment, foreign matter is less likely to be generated, and the foreign matter suppression effect becomes more significant.

[0267] Figure 4An ink cartridge is an example of a container for holding processing fluid. An ink pack 70 holds the processing fluid. The ink pack 70, together with a cartridge housing 72, constitutes an ink cartridge 40. The cartridge housing 72 includes a main body housing 76 and a cover 78 that protect the ink pack 70 by housing it inside. The ink pack has an ink supply port 74, and the main body housing has a hook 84, a notch 80, and a pressing part 82. The ink pack 70 includes a packaging film. The packaging film is made of plastics such as polyolefin, nylon, or other plastics. When the packaging film contains the aforementioned lubricant, foreign matter may sometimes be generated in the processing fluid contained in the ink pack during storage. Even in such cases, the generation of foreign matter can be suppressed when using the processing fluid of this embodiment, which is preferable.

[0268] 3. Examples and Comparative Examples

[0269] The present invention will now be specifically described through examples, but the invention is not limited to these examples. Unless otherwise stated, "parts" and "%" refer to mass. It should be noted that, unless otherwise stated, evaluations were conducted at a temperature of 25.0°C and a relative humidity of 40.0%.

[0270] 3.1. Preparation of the treatment solution

[0271] The components were added to a container to form the compositions shown in Tables 1 to 3. The mixture was stirred using a magnetic stirrer for 2 hours, and then filtered using a 5 μm pore size membrane filter to obtain the treatment solutions A to V used in the examples and comparative examples. It should be noted that the values ​​in the resin tables represent the amount of solids.

[0272] [Table 1]

[0273]

[0274] [Table 2]

[0275]

[0276] [Table 3]

[0277]

[0278] Supplementary explanations are provided for the abbreviations and product names shown in Tables 1 to 3.

[0279] PG: Propylene Glycol

[0280] ·1,2-HD: 1,2-Hexanediol

[0281] CPL: ε-caprolactam

[0282] TIPA: Triisopropanolamine

[0283] • DISPERBYK-190: Styrene-maleic acid water-soluble resin (manufactured by BYK Chemicals Japan Co., Ltd.) (non-reactive resin)

[0284] • DISPERBYK-2010: Styrene-maleic acid resin emulsion (manufactured by BYK Chemicals Japan Co., Ltd.) (non-reactive resin)

[0285] SN DISPERSANT 5033: Water-soluble acrylic resin (manufactured by San Nopco Co., Ltd.) (non-reactive resin)

[0286] SN DISPERSANT 5029: Styrene-maleic acid water-soluble resin (manufactured by San Nopco Co., Ltd.) (reactive resin)

[0287] • PITZCOL K-17: Nonionic water-soluble resin, polyvinylpyrrolidone (PVP) (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) (non-reactive resin)

[0288] • BYK-349: Organosilicon surfactant (manufactured by BYK Chemical Co., Ltd., Japan)

[0289] • Sufynol DF110D: A acetylenic diol surfactant (manufactured by Nissin Chemical Industries, Ltd.)

[0290] It should be noted that "non-reactive resin" refers to a resin that does not react with calcium formate aqueous solution, while "reactive resin" refers to a resin that reacts with calcium formate aqueous solution. The determination method is as follows.

[0291] Resin was added to the sample vial to make the amount of resin solids 0.1 g. Water was added to make a total of 8 g, and then 0.5 g of a 3% (w / w) aqueous solution of calcium formate was added and stirred. The state at this point was visually confirmed (evaluated at 25°C). Furthermore, the formation of precipitate was defined as "reactive," and the absence of precipitate was defined as "non-reactive."

[0292] 3.2. Preparation of Inkjet Ink

[0293] The components were added to a container to form the composition shown in Table 4. The mixture was stirred and mixed for 2 hours using a magnetic stirrer, and then dispersed using a bead mill filled with 0.3 mm diameter zirconia beads to ensure thorough mixing. After stirring for 1 hour, the mixture was filtered through a 5.0 μm PTFE membrane filter to obtain inkjet inks (A, B). Pure water was used as the ink source, and water was added to ensure that each ink reached 100% by mass. The pigments, dispersant resins, and dispersions were prepared as follows and used.

[0294] 50g of methyl ethyl ketone (MEK) was added to a flask equipped with a dropping funnel, nitrogen inlet tube, reflux condenser, thermometer, and stirrer. The temperature was raised to 75°C while bubbling with nitrogen. Using the dropping funnel, a mixture of 80g butyl methacrylate, 50g methyl methacrylate, 15g styrene, 20g methacrylic acid monomers, 50g MEK, and 500mg of polymerization initiator (azobisisobutyronitrile / AIBN) was added dropwise over 3 hours. After the dropwise addition, the mixture was refluxed for 6 hours. After natural cooling, the evaporated amount of MEK was added to obtain a resin solution (resin solids 50% by mass, acid value 79mg / KOH, Tg 65°C). A specified amount of 20% by mass sodium hydroxide aqueous solution was added to 20g of this solution as a neutralizing agent to neutralize 100% of the salt-forming groups. While stirring, 50g of pigment (CI Pigment Blue 15:3) was added little by little, and the mixture was then kneaded using a bead mill for 2 hours. 200g of deionized water was added to the obtained mixture and stirred. MEK was then distilled off under reduced pressure and heated. The concentration was then adjusted using deionized water to obtain a pigment dispersion (pigment solids 20% by mass, resin solids 5% by weight).

[0295] [Table 4]

[0296]

[0297] Provide supplementary explanations for the abbreviations and product names in Table 4.

[0298] • Joncryl 631: Styrene-acrylic resin emulsion (manufactured by BASF Corporation, Japan) • HI-TEC E-6500: Polyolefin wax emulsion (manufactured by Toho Chemical Co., Ltd.) Regarding other substances, see Tables 1-3. The cyan pigments in the tables are pigment solids.

[0299] 3.3. Evaluation Methods

[0300] 3.3.1. Printing Test

[0301] The printing test was conducted under the following conditions.

[0302] Printing press: SC-R5050 (manufactured by Seiko Epson Corporation) Modified press resolution: 1200×1200dpi

[0303] Printed design: All-over design (cyan)

[0304] Number of scans: 9; processing liquid and ink are applied simultaneously.

[0305] Tabletop paper surface temperature: 35℃

[0306] Secondary drying temperature: 80℃

[0307] Recording medium: Orajet 3165G-010 (manufactured by ORAFOL Japan, vinyl chloride membrane)

[0308] Tabletop gap: 1.7mm

[0309] 3.3.2. Evaluation of preservation stability

[0310] Seal 50g of each treatment solution in an aluminum bag (a three-layer laminated bag of nylon / aluminum / polyethylene, with polyethylene on the inner side and stearamide as a lubricant) to prevent air bubbles, and then place them in a 60℃ constant temperature bath for 5 and 14 days. Remove and allow to cool naturally, then allow 10g of the treatment solution to pass through... The filter (with a liquid flow area of ​​1 cm²) 2 The number of foreign objects was counted. Evaluation was conducted according to the following criteria, and the results were recorded in Tables 1 to 3.

[0311] A: The number of foreign objects is less than 50 under conditions of 60℃ and 14 days.

[0312] B: The number of foreign objects is more than 50 under conditions of 60℃ and 14 days; the number of foreign objects is less than 50 under conditions of 60℃ and 5 days.

[0313] C: The number of foreign objects is more than 50 under conditions of 60℃ and 5 days.

[0314] 3.3.3. Evaluation of scratch resistance

[0315] The SC-R5050 (manufactured by Seiko Epson Corporation, inkjet printer) was filled with the processing liquid and inkjet ink groups listed in Table 5, and a full-page pattern was printed on the recording medium (color ink adhesion amount of 12 mg / inch). 2 The amount of treatment fluid adhering is 1 mg / inch. 2 After being left at room temperature for 30 minutes, the ink-attached area was cut into rectangles of 30×150mm. The rectangles were then rubbed 100 times in a vibratory scratch resistance tester (load 500g) using a water-wetted plain woven fabric. The degree of ink peeling was visually evaluated at this point. The evaluation was conducted according to the following standards, and the results were recorded in Table 5.

[0316] AA: No stripping

[0317] A: Peeling occurred relative to an area less than 1 / 5 of the evaluation area.

[0318] B: Peeling occurs relative to an area less than 1 / 2 of the evaluation area.

[0319] C: Peeling occurred relative to an area exceeding 1 / 2 of the evaluation area.

[0320] 3.3.4. Evaluation of full-page image quality

[0321] The SC-R5050 (manufactured by Seiko Epson Corporation, inkjet printer) was filled with the processing liquid and inkjet ink groups listed in Table 5, and a full-page pattern was printed on the recording medium (color ink adhesion amount of 12 mg / inch). 2 The amount of treatment fluid adhering is 1 mg / inch. 2 Visually inspect the printed material. Evaluate it according to the following criteria and record the results in Table 5.

[0322] AA: No streaks (dark and light streaks) of uneven concentration extending along the main scan direction were observed.

[0323] A: There are a few dark and light streaks, but the concentration difference is small and not obvious.

[0324] B: There are dark and light stripes, and the concentration difference is large, but it is permissible.

[0325] C: Exists with varying shades of stripes and a large concentration difference, which is obvious.

[0326] [Table 5]

[0327]

[0328]

[0329] 3.4. Evaluation Results

[0330] The evaluation results are shown in Table 5. Table 5 records the processing solution, color ink, and pH difference between the two used in each example. As can be seen from the table, in the examples using processing solutions containing polyvalent metal salts, resins selected from acrylic resins and maleic acid resins, and compounds selected from organic acids and organic amines, with the resin content being less than 1% by mass relative to the total mass, and the pH being 5.5 or higher and less than 7.5, the storage stability and image quality of the processing solution were good.

[0331] This invention includes configurations that are substantially the same as those described in the embodiments, such as configurations with the same function, method, and result, or configurations with the same purpose and effect. Additionally, this invention includes configurations that replace non-essential parts of the configurations described in the embodiments. Furthermore, this invention includes configurations that can achieve the same effect as those described in the embodiments, or configurations that can achieve the same purpose. Additionally, this invention includes configurations that incorporate known techniques into the configurations described in the embodiments.

[0332] Based on the above implementation methods and variations, the following content is derived.

[0333] A processing liquid, which is used for recording together with inkjet ink, wherein,

[0334] The inkjet ink is a water-based ink composition.

[0335] The treatment solution contains polyvalent metal salts, resins selected from acrylic resins and maleic acid resins, and compounds selected from organic acids and organic amines.

[0336] The resin content is less than 1% by mass relative to the total mass of the treatment solution.

[0337] The pH of the treatment solution is above 5.5 and below 7.5.

[0338] According to this processing solution, by containing resin, foreign matter is not easily generated even if the components in contact with the processing solution contain lubricants. Moreover, by containing resin in an amount of less than 1% by mass, the scratch resistance and image quality of the image formed by inkjet ink are good.

[0339] For the aforementioned processing fluid, the component of the recording device that comes into contact with the processing fluid may contain a fatty acid-based lubricant.

[0340] According to this treatment fluid, even when the component contains a lubricant that is more likely to generate foreign matter, foreign matter is less likely to be generated, and the foreign matter suppression effect is more significant.

[0341] The aforementioned processing fluid can be ejected from the inkjet head for use in the recording.

[0342] Based on this treatment solution, the amount of treatment solution used can be controlled.

[0343] For the above-mentioned processing solution, the pH difference between the processing solution and the pH of the inkjet ink can be less than 3.

[0344] According to this treatment solution, suppressing the pH of inkjet ink from becoming too high can improve the scratch resistance and image quality of images formed by inkjet ink.

[0345] In the above-mentioned treatment solution, the resin can be a water-soluble resin.

[0346] The treatment solution can further suppress the generation of foreign matter.

[0347] In the above-mentioned treatment solution, the content of the resin relative to the total mass of the treatment solution can be more than 0.05% by mass and less than 0.6% by mass.

[0348] This treatment solution can improve the scratch resistance of images formed by inkjet ink.

[0349] In the above-mentioned treatment solution, the content of the polyvalent metal salt relative to the total mass of the treatment solution can be more than 0.5% by mass and less than 10% by mass.

[0350] This processing solution can improve the image quality of images formed from inkjet inks.

[0351] In the above-described treatment solution, the total amount of the compounds selected from organic acids and organic amines may be less than 1% by mass relative to the total mass of the treatment solution.

[0352] Based on this treatment solution, the pH of the treatment solution can be easily adjusted to be above 5.5 and below 7.5.

[0353] The above-mentioned treatment solution may contain the organic acid, and the organic acid may be a dicarboxylic acid compound.

[0354] This treatment solution can improve the scratch resistance of images formed by inkjet ink.

[0355] In the above-mentioned treatment solution, the polyvalent metal salt can be an organic acid polyvalent metal salt.

[0356] According to this treatment solution, due to the use of organic acid polyvalent metal salts with low deliquescence, the water resistance, moisture resistance and scratch resistance of the recorded material are improved.

[0357] In the above-mentioned treatment solution, the resin can be a resin that does not react with the calcium formate aqueous solution.

[0358] According to this treatment fluid, even if the components in contact with the treatment fluid contain lubricant, it is less likely to generate foreign matter.

[0359] The above-mentioned treatment solution may contain water-soluble low-molecular-weight organic compounds.

[0360] The aforementioned processing solution can be used for recording on low-absorbency or non-absorbency recording media.

[0361] A recording method, which uses the above-mentioned processing liquid and inkjet ink, includes the following steps:

[0362] The process of attaching the processing liquid to the recording medium, and

[0363] The ink adhesion step involves ejecting the inkjet ink from the inkjet head and attaching it to the recording medium.

[0364] According to this recording method, even if the components in contact with the processing liquid contain lubricant, foreign matter is less likely to be generated. Furthermore, it enables the scratch resistance and image quality of images formed from inkjet inks to be improved.

[0365] An ink group comprising the above-mentioned processing liquid and inkjet ink.

[0366] According to this ink group, even if the components in contact with the processing liquid contain lubricant, foreign matter is not easily generated. Moreover, it enables the images formed by inkjet ink to have good scratch resistance and image quality.

Claims

1. An aqueous treatment solution, characterized in that, A processing liquid used for recording along with inkjet inks. The inkjet ink is a water-based ink composition. The treatment solution contains polyvalent metal salts, resins selected from acrylic resins and maleic acid resins, and compounds selected from organic acids and organic amines. The resin content is less than 1% by mass relative to the total mass of the treatment solution. The pH of the treatment solution is above 5.5 and below 7.

5. The total amount of the compounds selected from organic acids and organic amines relative to the total mass of the treatment solution is less than 0.2% by mass. The content of the polyvalent metal salt is 1% by mass or more relative to the total mass of the treatment solution. The resin content is less than 0.8% by mass relative to the total mass of the treatment liquid.

2. The treatment solution according to claim 1, wherein, The components of the recording device that come into contact with the processing liquid contain fatty acid-based lubricants.

3. The treatment solution according to claim 1, wherein, The processing fluid is ejected from the inkjet head for the recording.

4. The treatment solution according to claim 1, wherein, The pH difference between the processing solution and the inkjet ink is less than 3.

5. The treatment solution according to claim 1, wherein, The resin is a water-soluble resin.

6. The treatment solution according to claim 1, wherein, The resin content is 0.05% by mass or more and 0.6% by mass or less relative to the total mass of the treatment liquid.

7. The treatment solution according to claim 1, wherein, The content of the polyvalent metal salt is 1% by mass or more and 10% by mass or less relative to the total mass of the treatment solution.

8. The treatment solution according to claim 1, wherein, The total amount of the compounds selected from organic acids and organic amines is less than 0.1% by mass relative to the total mass of the treatment solution.

9. The treatment solution according to claim 1, wherein, The treatment solution contains the organic acid, and the organic acid is a dicarboxylic acid compound.

10. The treatment solution according to claim 1, wherein, The polyvalent metal salt is an organic acid polyvalent metal salt.

11. The treatment solution according to claim 1, wherein, The resin is a resin that does not react with calcium formate aqueous solution.

12. The treatment solution according to claim 1, wherein, The treatment solution contains water-soluble low-molecular-weight organic compounds.

13. The treatment solution according to claim 1, wherein, The processing fluid is used for recording on low-absorbency or non-absorbency recording media.

14. A recording method, characterized in that, For a recording method using the processing liquid and inkjet ink as described in claim 1, The recording method includes the following steps: The process of attaching the processing liquid to the recording medium, and The ink adhesion step involves ejecting the inkjet ink from the inkjet head and attaching it to the recording medium.

15. An ink set, characterized in that... ， It includes the processing liquid and inkjet ink as described in claim 1.

Images