JP7114916B2 - Liquid composition, treatment liquid, image forming method, and image forming apparatus - Google Patents

Description

The present invention relates to a liquid composition, a treatment liquid, an image forming method, and an image forming apparatus .

2. Description of the Related Art As inks used in applications requiring water resistance and light resistance such as posters, inks using coloring materials such as pigments are known. When such ink is ejected by an inkjet recording method onto a low-absorbent recording medium such as coated paper used for commercial printing, adjacent droplets coalesce on the recording medium, resulting in image defects (beads). ding) occurs. As a method for eliminating image defects due to beading, there is known a method of applying a treatment liquid containing a polyvalent metal salt that has the effect of aggregating the coloring material in the ink onto the recording medium before the ink is ejected. there is

Japanese Patent Laid-Open No. 2002-200000 describes an inkjet method in which a treatment liquid is applied to a recording medium and then ink is applied to the recording medium to which the treatment liquid has been applied, with the object of suppressing precipitation of a polyvalent metal salt contained in the treatment liquid. A processing liquid used in a recording method, containing water, glycerin, and at least one polyvalent metal salt selected from the group consisting of calcium nitrate and magnesium nitrate, wherein the content of glycerin in the processing liquid is from 10 to 10. It is disclosed to use a treatment liquid for inkjet recording, which is 50% by mass and has a polyvalent metal salt content of 0.8 to 2.0 mol/L in the treatment liquid.

However, when a liquid composition such as a conventional treatment liquid having a high glycerin content is applied to a recording medium and then ink is applied to form dots, the ink is applied onto the recording medium on which a large amount of glycerin remains. As a result, the coloring material in the applied ink is wetted and spread by the glycerin, causing deterioration of graininess due to partial collapsing of dots. Therefore, it is difficult to obtain a liquid composition that can suppress the deterioration of graininess while suppressing the occurrence of beading and precipitation of polyvalent metal salts.

The invention according to claim 1 comprises a polyvalent metal salt, glycerin, a compound (1) having a structure obtained by addition polymerization of polyoxyethylene to diglycerin, and a compound having a structure obtained by addition polymerization of polyoxypropylene to diglycerin ( 2) is a liquid composition containing at least one selected from

The liquid composition of the present invention exhibits an excellent effect of suppressing the deterioration of graininess while suppressing the occurrence of beading and precipitation of polyvalent metal salts.

FIG. 1 is a schematic diagram showing an example of an image forming apparatus.

An embodiment of the present invention will be described below.

<< liquid composition >>
The liquid composition of the present invention comprises a polyvalent metal salt, glycerin, a compound (1) having a structure in which polyoxyethylene is addition-polymerized to diglycerin, and a compound having a structure in which polyoxypropylene is addition-polymerized to diglycerin ( 2), and optionally water, an organic solvent, and other components.

<Compound (1) and Compound (2)>
The liquid composition has a structure in which polyoxyalkylene is addition-polymerized to diglycerin, a compound (1) having a structure in which polyoxyethylene is addition-polymerized to diglycerin, and a structure in which polyoxypropylene is addition-polymerized to diglycerin. It contains at least one selected from compound (2). That is, the liquid composition may contain compound (1) or compound (2) alone, or may contain both compound (1) and compound (2).
When the liquid composition does not contain a structure obtained by addition polymerization of polyoxyalkylene to diglycerol such as compound (1) or compound (2) and is used as a treatment liquid, it is applied to the recording medium after application of the treatment liquid. In the dots formed with the ink that is applied, deterioration of graininess occurs due to partial collapsing of the dots. In particular, when using a treatment liquid that does not contain a structure in which polyoxyalkylene is added to diglycerin such as compound (1) and compound (2), when using a low-absorbent recording medium such as coated paper, When the ink is applied to the recording medium to which the treatment liquid has been applied without drying it, graininess due to partial collapsing of the dots becomes conspicuous. In addition, when a processing liquid that does not contain a structure in which polyoxyalkylene is added to diglycerin such as compound (1) or compound (2) is used, the hygroscopicity and moisturizing properties of the processing liquid are reduced, which will be described later. Crystals of the polyvalent metal salt are likely to be precipitated, and the later-described aggregating function of the coloring material in the ink is lowered.

一般式（１）で表される化合物において、ｍ、ｎ、ｏ、及びｐはそれぞれ独立して０、又は１以上の自然数である。また、ｍ、ｎ、ｏ、及びｐから選ばれる少なくとも１つは、１以上の整数である。
また、ｍ＋ｎ＋ｏ＋ｐは、６以上４０以下の整数であることが好ましく、１３以上３０以下の整数であることがより好ましい。ｍ＋ｎ＋ｏ＋ｐが６以上であることにより、本願の液体組成物を処理液として用いた場合、処理液を付与した後の記録媒体に付与されるインクで形成されるドットにおいて、ドットの部分的な崩れに起因する粒状性の悪化が抑制され、ｍ＋ｎ＋ｏ＋ｐが１３以上であることにより更に抑制される。また、ｍ＋ｎ＋ｏ＋ｐが４０以下であることにより、本願の液体組成物を処理液として用いた場合、処理液における吸湿性と保湿性が向上し、後述する多価金属塩の結晶の析出が抑制されることで後述するインク中の色材に対する凝集機能が向上し、ｍ＋ｎ＋ｏ＋ｐが３０以下であることにより更に向上する。 The compound (1) preferably contains, for example, a compound represented by the following general formula (1).

In the compound represented by the general formula (1), m, n, o and p are each independently 0 or a natural number of 1 or more. At least one selected from m, n, o, and p is an integer of 1 or more.
In addition, m+n+o+p is preferably an integer of 6 or more and 40 or less, and more preferably an integer of 13 or more and 30 or less. Since m + n + o + p is 6 or more, when the liquid composition of the present application is used as a treatment liquid, dots formed with ink applied to a recording medium after application of the treatment liquid do not partially collapse. Deterioration of graininess resulting from this is suppressed, and is further suppressed by m+n+o+p being 13 or more. In addition, since m+n+o+p is 40 or less, when the liquid composition of the present application is used as a treatment liquid, the hygroscopicity and moisture retention properties of the treatment liquid are improved, and precipitation of polyvalent metal salt crystals, which will be described later, is suppressed. As a result, the aggregating function for the coloring material in the ink, which will be described later, is improved, and further improved when m+n+o+p is 30 or less.

一般式（２）で表される化合物において、ｑ、ｒ、ｓ、及びｔはそれぞれ独立して０、又は１以上の自然数である。また、ｑ、ｒ、ｓ、及びｔから選ばれる少なくとも１つは、１以上の整数である。
また、ｑ＋ｒ＋ｓ＋ｔは、４以上２４以下の整数であることが好ましく、９以上１８以下の整数であることがより好ましい。ｑ＋ｒ＋ｓ＋ｔが４以上であることにより、本願の液体組成物を処理液として用いた場合、処理液を付与した後の記録媒体に付与されるインクで形成されるドットにおいて、ドットの部分的な崩れに起因する粒状性の悪化が抑制され、ｑ＋ｒ＋ｓ＋ｔが９以上であることにより更に抑制される。また、ｑ＋ｒ＋ｓ＋ｔが２４以下であることにより、本願の液体組成物を処理液として用いた場合、処理液における吸湿性と保湿性が向上し、後述する多価金属塩の結晶の析出が抑制されることで後述するインク中の色材に対する凝集機能が向上し、ｑ＋ｒ＋ｓ＋ｔが１８以下であることにより更に向上する。 The compound (2) preferably contains, for example, a compound represented by the following general formula (2).

In the compound represented by the general formula (2), q, r, s and t are each independently 0 or a natural number of 1 or more. At least one selected from q, r, s, and t is an integer of 1 or greater.
Also, q+r+s+t is preferably an integer of 4 or more and 24 or less, and more preferably an integer of 9 or more and 18 or less. When q + r + s + t is 4 or more, when the liquid composition of the present application is used as a treatment liquid, dots formed with ink applied to a recording medium after application of the treatment liquid do not partially collapse. Deterioration of graininess caused by the graininess is suppressed, and is further suppressed by setting q+r+s+t to be 9 or more. Further, since q+r+s+t is 24 or less, when the liquid composition of the present application is used as a treatment liquid, the hygroscopicity and moisture retention properties of the treatment liquid are improved, and precipitation of polyvalent metal salt crystals, which will be described later, is suppressed. As a result, the aggregating function for the coloring material in the ink, which will be described later, is improved.

Compound (1) is preferably contained in an amount of 0.5% by mass or more and 50.0% by mass or less, more preferably 1.0% by mass or more and 30.0% by mass or less, relative to the total amount of the liquid composition. , more preferably 2.0% by mass or more and 20.0% by mass or less.
Compound (2) is preferably contained in an amount of 0.5% by mass or more and 50.0% by mass or less, more preferably 1.0% by mass or more and 30.0% by mass or less, relative to the total amount of the liquid composition. , more preferably 2.0% by mass or more and 20.0% by mass or less.

<Glycerin>
The liquid composition contains glycerin. When a liquid composition containing at least one selected from compound (1) and compound (2) is used as a treatment liquid without glycerin, the solubility and moisture retention properties of the polyvalent metal salt in the treatment liquid are reduced. , crystals of a polyvalent metal salt, which will be described later, are likely to precipitate. When such a liquid composition that easily precipitates polyvalent metal salt crystals is applied onto a recording medium, the precipitated crystals on the recording medium may cause abnormal images such as uneven image density.

10. Glycerin is preferably contained in an amount of 5.0% by mass or more and 60.0% by mass or less, more preferably 10.0% by mass or more and 50.0% by mass or less, relative to the total amount of the liquid composition. It is more preferable to contain 0% by mass or more and 45.0% by mass or less.

Further, the mass ratio of the total content of compound (1) and compound (2) in the liquid composition to the total content of glycerin, compound (1) and compound (2) in the liquid composition is 0. .1 or more and 0.5 or less. Since the mass ratio is 0.1 or more, when the liquid composition of the present application is used as a treatment liquid, in the dots formed with the ink applied to the recording medium after applying the treatment liquid, the dots are partially Deterioration of graininess due to uneven collapse is suppressed. Further, since the mass ratio is 0.5 or less, when the liquid composition of the present application is used as a treatment liquid, the hygroscopicity and moisture retention properties of the treatment liquid are improved, and precipitation of polyvalent metal salt crystals, which will be described later, is prevented. Suppression improves the function of aggregating the coloring material in the ink, which will be described later.

<Polyvalent metal salt>
The liquid composition contains a polyvalent metal salt. The polyvalent metal salt associates with the colorant in the ink by a charge-like action to form an aggregate of the colorant, separate the colorant from the liquid phase, and promote fixation onto the recording medium. By containing a polyvalent metal salt in the liquid composition, when the liquid composition is used as a treatment liquid, the occurrence of beading can be suppressed even when a recording medium with low ink absorption is used, and high image quality can be achieved. image can be formed.

The polyvalent metal salt is not particularly limited and can be appropriately selected depending on the purpose. Examples include titanium compounds, chromium compounds, copper compounds, cobalt compounds, strontium compounds, barium compounds, iron compounds, aluminum compounds, calcium compounds, salts of magnesium compounds, zinc compounds, nickel compounds, and the like. These may be used individually by 1 type, and may use 2 or more types together. Among these, salts of calcium compounds, magnesium compounds, and nickel compounds are preferable, and alkaline earth metal salts such as calcium and magnesium are more preferable, since they can effectively agglomerate colorants such as pigments.
The polyvalent metal salt is preferably ionic. In particular, it is preferable that the polyvalent metal salt is a calcium salt.

The magnesium compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include magnesium chloride, magnesium acetate, magnesium sulfate, magnesium nitrate, and magnesium silicate.
The calcium compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include calcium carbonate, calcium nitrate, calcium chloride, calcium acetate, calcium sulfate and calcium silicate.
The barium compound is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include barium sulfate.
The zinc compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include zinc sulfide and zinc carbonate.
The aluminum compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include aluminum silicate and aluminum hydroxide.
Among these, magnesium sulfate, magnesium nitrate, calcium nitrate, and the like, which are highly soluble in glycerin and at least one selected from compound (1) and compound (2), are preferred. When a liquid composition containing these polyvalent metal salts is used as a treatment liquid, precipitation of crystals of the polyvalent metal salt is suppressed, and the function of aggregating the coloring material in the ink, which will be described later, is improved.

Moreover, the content of the polyvalent metal salt relative to the total amount of the liquid composition is preferably 0.8 mol/kg or more and 1.4 mol/kg or less. When the content is 0.8 mol/kg or more, beading can be suppressed even when a recording medium with low ink absorption is used, and high-quality images can be formed. Moreover, when the content is 1.4 mol/kg or less, the storage stability of the liquid composition is improved.

Further, the mass ratio of the total content of glycerin, compound (1), and compound (2) in the liquid composition to the content of polyvalent metal salt in the liquid composition is 1.05 or more and 1.40 or less. is preferably When the liquid composition containing the polyvalent metal salt is used as the treatment liquid, the mass ratio of 1.05 or more suppresses precipitation of crystals of the polyvalent metal salt, and aggregation of the coloring material in the ink described later is suppressed. Improve functionality. Further, when the mass ratio is 1.40 or less, the storage stability of the liquid composition is improved.

<Organic solvent>
In the present invention, glycerin and at least one selected from compound (1) and compound (2) are used as organic solvents, but other organic solvents can also be used in combination if necessary. As another organic solvent, it is preferable to use a water-soluble organic solvent. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1, 3-pentanediol, petriol and the like.
Examples of polyhydric alcohol alkyl ethers include polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. and ethers.
Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and the like. mentioned.
Amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide and the like.
Amines include monoethanolamine, diethanolamine, triethylamine, and the like.
Examples of sulfur-containing compounds include dimethylsulfoxide, sulfolane, thiodiethanol and the like.
Other organic solvents include propylene carbonate and ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250° C. or less because it not only functions as a wetting agent but also provides good drying properties.

The content of the organic solvent in the liquid composition is not particularly limited and can be appropriately selected according to the purpose. 20% by mass or more and 60% by mass or less is more preferable.

<Water>
The content of water in the liquid composition is not particularly limited and can be appropriately selected according to the purpose. % or more and 60 mass % or less is more preferable.

<Surfactant>
The liquid composition may contain a surfactant. Surfactants have the effect of lowering the surface tension of the liquid composition, improving the wettability of various recording media when the liquid composition is used as the treatment liquid, and enabling the treatment liquid to be applied evenly. . Surfactants allow the processing liquid to moderately wet the recording medium, thereby increasing the permeation speed of the processing liquid into various recording media. By increasing the permeation speed of the treatment liquid, excessive aggregation of the coloring material contained in the ink applied to the recording medium to which the treatment liquid is applied can be suppressed.

Any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used as surfactants.
The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the purpose. Among them, those that do not decompose even at high pH are preferred. Examples of silicone-based surfactants include side chain-modified polydimethylsiloxane, both-end-modified polydimethylsiloxane, single-end-modified polydimethylsiloxane, and side-chain both-end-modified polydimethylsiloxane. Those having a polyoxyethylene group or a polyoxyethylene-polyoxypropylene group as a modifying group are particularly preferred because they exhibit good properties as water-based surfactants. As the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.
Examples of fluorine-based surfactants include perfluoroalkylsulfonic acid compounds, perfluoroalkylcarboxylic acid compounds, perfluoroalkylphosphoric acid ester compounds, perfluoroalkylethylene oxide adducts, and perfluoroalkyl ether groups in side chains. Polyoxyalkylene ether polymer compounds are particularly preferred due to their low foaming properties. Examples of perfluoroalkylsulfonic acid compounds include perfluoroalkylsulfonic acids, perfluoroalkylsulfonates, and the like. Examples of perfluoroalkylcarboxylic acid compounds include perfluoroalkylcarboxylic acids and perfluoroalkylcarboxylic acid salts. Examples of polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in side chains include sulfuric acid ester salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in side chains, and polyoxyalkylene ether polymers having perfluoroalkyl ether groups in side chains. Examples thereof include salts of oxyalkylene ether polymers. Counter ions of salts in these _{fluorosurfactants} include Li, Na, K, _NH4 , _NH3CH2CH2OH , _{NH2 ( CH2CH2OH} ) ₂ , and _{NH ( CH2CH2OH} ). ₃ and the like.
Examples of amphoteric surfactants include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethylbetaine and the like.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, and salts of polyoxyethylene alkyl ether sulfates.
These may be used individually by 1 type, or may use 2 or more types together.

（但し、一般式（Ｓ－１）式中、ｍ、ｎ、ａ、及びｂは、それぞれ独立に、整数を表わし、Ｒは、アルキレン基を表し、Ｒ’は、アルキル基を表す。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ－６１８、ＫＦ－６４２、ＫＦ－６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ－ＳＳ－５６０２、ＳＳ－１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ－２１０５、ＦＺ－２１１８、ＦＺ－２１５４、ＦＺ－２１６１、ＦＺ－２１６２、ＦＺ－２１６３、ＦＺ－２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ－３３、ＢＹＫ－３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）などが挙げられる。 The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the intended purpose. Examples include polydimethylsiloxane modified at both ends, and polyether-modified silicone surfactants having polyoxyethylene groups or polyoxyethylene polyoxypropylene groups as modifying groups are particularly preferred because they exhibit good properties as water-based surfactants. .
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. Commercially available products are available from, for example, BYK Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nihon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.
The above polyether-modified silicone-based surfactant is not particularly limited and can be appropriately selected according to the purpose. Examples include those introduced into the side chain of the Si portion of siloxane.

(However, in general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.)
Commercially available products can be used as the above polyether-modified silicone-based surfactants. 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Dow Corning Toray Silicone Co., Ltd.), BYK-33, BYK-387 (BYK-Chemie Corporation), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) and the like.

上記一般式（Ｆ－１）で表される化合物において、水溶性を付与するためにｍは０～１０の整数が好ましく、ｎは０～４０の整数が好ましい。

上記一般式（Ｆ－２）で表される化合物において、ＹはＨ、又はＣｍＦ_２ｍ＋１でｍは１～６の整数、又はＣＨ_２ＣＨ（ＯＨ）ＣＨ_２－ＣｍＦ_２ｍ＋１でｍは４～６の整数、又はＣｐＨ_２ｐ＋１でｐは１～１９の整数である。ｎは１～６の整数である。ａは４～１４の整数である。
上記のフッ素系界面活性剤としては市販品を使用してもよい。この市販品としては、例えば、サーフロンＳ－１１１、Ｓ－１１２、Ｓ－１１３、Ｓ－１２１、Ｓ－１３１、Ｓ－１３２、Ｓ－１４１、Ｓ－１４５（いずれも、旭硝子株式会社製）；フルラードＦＣ－９３、ＦＣ－９５、ＦＣ－９８、ＦＣ－１２９、ＦＣ－１３５、ＦＣ－１７０Ｃ、ＦＣ－４３０、ＦＣ－４３１（いずれも、住友スリーエム株式会社製）；メガファックＦ－４７０、Ｆ－１４０５、Ｆ－４７４（いずれも、大日本インキ化学工業株式会社製）；ゾニール（Ｚｏｎｙｌ）ＴＢＳ、ＦＳＰ、ＦＳＡ、ＦＳＮ－１００、ＦＳＮ、ＦＳＯ－１００、ＦＳＯ、ＦＳ－３００、ＵＲ、キャプストーンＦＳ－３０、ＦＳ－３１、ＦＳ－３１００、ＦＳ－３４、ＦＳ－３５（いずれも、Ｃｈｅｍｏｕｒｓ社製）；ＦＴ－１１０、ＦＴ－２５０、ＦＴ－２５１、ＦＴ－４００Ｓ、ＦＴ－１５０、ＦＴ－４００ＳＷ（いずれも、株式会社ネオス社製）、ポリフォックスＰＦ－１３６Ａ，ＰＦ－１５６Ａ、ＰＦ－１５１Ｎ、ＰＦ－１５４、ＰＦ－１５９（オムノバ社製）、ユニダインＤＳＮ－４０３Ｎ（ダイキン工業株式会社製）などが挙げられ、これらの中でも、Ｃｈｅｍｏｕｒｓ社製のＦＳ－３１００、ＦＳ－３４、ＦＳ－３００、株式会社ネオス製のＦＴ－１１０、ＦＴ－２５０、ＦＴ－２５１、ＦＴ－４００Ｓ、ＦＴ－１５０、ＦＴ－４００ＳＷ、オムノバ社製のポリフォックスＰＦ－１５１Ｎ及びダイキン工業株式会社製のユニダインＤＳＮ－４０３Ｎが特に好ましい。 As the fluorosurfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of fluorine-based surfactants include perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in side chains. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain is preferable because of its low foamability, and in particular, fluorine-based compounds represented by general formulas (F-1) and (F-2) Surfactants are preferred.

In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.

In the compound represented by the above general formula (F-2), Y is H, or CmF _2m+1 and m is an integer of 1 to 6, or CH ₂ CH(OH)CH ₂ -CmF _2m+1 and m is 4 to 6 Integer, or CpH _2p+1 where p is an integer from 1-19. n is an integer of 1-6. a is an integer from 4 to 14;
Commercially available products may be used as the fluorosurfactant. Examples of commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fleurard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (both manufactured by Sumitomo 3M); Megafac F-470, F -1405, F-474 (both manufactured by Dainippon Ink and Chemicals); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT-250, FT-251, FT-400S, FT-150, FT- 400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) Among them, Chemours FS-3100, FS-34, FS-300, Neos Co., Ltd. FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW, Polyfox PF-151N manufactured by Omnova and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferred.

The content of the surfactant in the ink is not particularly limited and can be appropriately selected according to the purpose. % or less is more preferable.

<Antifoaming agent>
The antifoaming agent is not particularly limited, and examples thereof include silicone antifoaming agents, polyether antifoaming agents, and fatty acid ester antifoaming agents. These may be used individually by 1 type, or may use 2 or more types together. Among these, silicone-based antifoaming agents are preferred because of their excellent foam breaking effect.

<Preservative and antifungal agent>
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Antirust agent>
The rust inhibitor is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

<pH adjuster>
The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

<Method for producing liquid composition>
A liquid composition can be obtained by dispersing or dissolving the constituent components in an aqueous medium and, if necessary, stirring and mixing. Stirring and mixing can be carried out using a stirrer using ordinary stirring blades, a magnetic stirrer, a high-speed disperser, or the like.

<Physical properties of the liquid composition>
Physical properties of the liquid composition are not particularly limited, and viscosity, surface tension, pH and the like can be appropriately selected depending on the purpose.
The viscosity of the liquid composition is preferably 0.5 mPa·s or more and 30 mPa·s or less at 25°C. Here, the viscosity can be measured using, for example, a viscometer (device name: RE-550L, manufactured by Toki Sangyo Co., Ltd.).
The surface tension of the liquid composition is preferably 45 mN/m or less, more preferably 40 mN/m or less at 25°C.
The pH of the liquid composition is, for example, preferably 4 or more and 12 or less, more preferably 6 or more and 10 or less.

<Application of liquid composition>
A liquid composition is preferably used as a treatment liquid. The treatment liquid is a liquid that has the effect of aggregating the coloring material in the ink, and is applied to the recording medium. This makes it possible, for example, to aggregate the colorant in the ink that is later applied to the recording medium to which the treatment liquid has been applied.

<<Ink>>
Organic solvents, water, coloring materials, resins, additives, and the like used in the ink are described below.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and any water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- 1,3-pentanediol, petriol and the like.
Examples of polyhydric alcohol alkyl ethers include polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. and ethers.
Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and the like. mentioned.
Amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide and the like.
Amines include monoethanolamine, diethanolamine, triethylamine, and the like.
Examples of sulfur-containing compounds include dimethylsulfoxide, sulfolane, thiodiethanol and the like.
Other organic solvents include propylene carbonate and ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250° C. or less because it not only functions as a wetting agent but also provides good drying properties.

The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose. 20% by mass or more and 60% by mass or less is more preferable.

<Water>
The content of water in the ink is not particularly limited and can be appropriately selected according to the purpose. % or more and 60 mass % or less is more preferable.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used individually by 1 type, and may use 2 or more types together. Mixed crystals may also be used as pigments.
Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy color pigments such as gold and silver, and metallic pigments.
As inorganic pigments, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, carbon black produced by known methods such as contact method, furnace method, thermal method, etc. can be used.
Organic pigments include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , dye chelates (eg, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of pigments for black include carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black and channel black, or copper and iron (C.I. Pigment Black 11). , metals such as titanium oxide, and organic pigments such as aniline black (C.I. Pigment Black 1).
Further, for color, C.I. I. Pigment yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52: 2, 53:1, 57:1 (brilliant carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88, 101 (red red), 104, 105, 106, 108 ( cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (rhodamine lake), 3, 5:1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15:1, 15:2, 15:3, 15:4 (phthalocyanine blue), 16, 17:1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.
As dyes, acid dyes, direct dyes, reactive dyes, and basic dyes can be used without particular limitation, and may be used singly or in combination of two or more.
As a dye, for example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. and Reactive Black 3,4,35.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoints of improving image density, good fixability, and ejection stability. It is below.

As a method of dispersing the pigment to obtain an ink, a method of introducing a hydrophilic functional group into the pigment to make it a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing the pigment, and a method of dispersing the pigment using a dispersant. method, etc.
As a method of making a self-dispersing pigment by introducing a hydrophilic functional group into a pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) to make it dispersible in water. are mentioned.
As a method of coating the surface of a pigment with a resin and dispersing it, there is a method of encapsulating the pigment in microcapsules to make it dispersible in water. This can be rephrased as a resin-coated pigment. In this case, all the pigments mixed in the ink need not be coated with a resin, and uncoated pigments or partially coated pigments may be dispersed in the ink as long as the effects of the present invention are not impaired. may be
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant typified by surfactants.
As the dispersant, it is possible to use, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. depending on the pigment.
As a dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and sodium naphthalenesulfonate formalin condensate can also be suitably used as a dispersant.
A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
Inks can be obtained by mixing materials such as water and organic solvents with pigments. Ink can also be produced by mixing a pigment, water, a dispersant, and the like to form a pigment dispersion, and then mixing materials such as water and an organic solvent.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and optionally other components, and adjusting the particle size. Dispersion should be carried out using a disperser.
The particle diameter of the pigment in the pigment dispersion is not particularly limited, but the dispersion stability of the pigment is improved, and the image quality such as ejection stability and image density is improved. 500 nm or less is preferable, and 20 nm or more and 150 nm or less is more preferable. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected according to the purpose. 50% by mass or less is preferable, and 0.1% by mass or more and 30% by mass or less is more preferable.
It is preferable to filter coarse particles with a filter, a centrifugal separator, or the like, and deaerate the pigment dispersion, if necessary.

<Resin>
The type of resin contained in the ink is not particularly limited and can be appropriately selected according to the purpose. resins, styrene-butadiene-based resins, vinyl chloride-based resins, acrylic-styrene-based resins, acrylic-silicone-based resins, and the like.
Resin particles made of these resins may also be used. Ink can be obtained by mixing resin particles in a resin emulsion state in which water is dispersed as a dispersion medium with a material such as a coloring material or an organic solvent. As the resin particles, appropriately synthesized ones may be used, or commercially available products may be used. Moreover, these may be used individually by 1 type, or may be used in combination of 2 or more types of resin particles.

The volume average particle diameter of the resin particles is not particularly limited and can be appropriately selected according to the intended purpose. 200 nm or less is more preferable, and 10 nm or more and 100 nm or less is particularly preferable.
The volume average particle diameter can be measured, for example, using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

The content of the resin is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoint of fixability and storage stability of the ink, the content is 1% by mass or more and 30% by mass or less based on the total amount of the ink. is preferable, and 5% by mass or more and 20% by mass or less is more preferable.

<Solid content in ink>
The particle size of the solid content in the ink is not particularly limited, and can be appropriately selected according to the purpose. From the viewpoint of enhancing image quality such as ejection stability and image density, the maximum frequency of the particle size of the solid content in the ink is preferably 20 nm or more and 1000 nm or less, more preferably 20 nm or more and 150 nm or less, in terms of the maximum number. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

<Other ingredients>
The ink may optionally contain surfactants, antifoaming agents, antiseptic/antifungal agents, antirust agents, pH adjusters, etc. These are the same as those contained in the above liquid composition.

<Ink manufacturing method>
The ink can be obtained by dispersing or dissolving the constituent components in an aqueous medium and, if necessary, stirring and mixing. Stirring and mixing can be carried out using a stirrer using ordinary stirring blades, a magnetic stirrer, a high-speed disperser, or the like.

<Physical properties of ink>
The physical properties of the ink are not particularly limited and can be appropriately selected depending on the intended purpose. For example, viscosity, surface tension, pH and the like are preferably within the following ranges.
The viscosity of the ink at 25° C. is preferably 5 mPa·s or more and 30 mPa·s or less, more preferably 5 mPa·s or more and 25 mPa·s or less, from the viewpoint of improving the print density and character quality and obtaining good ejection properties. more preferred. Here, the viscosity can be measured using, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). Measurement conditions are 25° C., standard cone rotor (1°34′×R24), sample liquid volume 1.2 mL, rotation speed 50 rpm, 3 minutes.
The static surface tension of the ink is preferably 25 mN/m or less, more preferably 22 mN/m or less at 25° C. from the viewpoints that the ink is suitably leveled on the recording medium and the drying time of the ink is shortened. When ink with such a low surface tension is used, graininess deteriorates due to partial collapsing of the dots in the dots formed with the ink applied to the recording medium after the application of the treatment liquid. Likely to happen. Therefore, it is preferable to use an ink having a low surface tension in combination with the liquid composition of the present application because it is possible to suppress deterioration of graininess caused by partial collapsing of dots.
The pH of the ink is preferably 7 or more and 12 or less, more preferably 8 or more and 11 or less, from the viewpoint of preventing corrosion of metal members that come into contact with the liquid.

<<Recording medium>>
The recording medium can be used without any particular limitation, and plain paper, glossy paper, special paper, cloth, etc. can also be used, but it is particularly preferably used for low-permeability substrates (low-absorption substrates). be able to.
A low-permeability substrate means a substrate having a surface with low water permeability, absorption, or adsorption, and includes materials that have many cavities inside but are not open to the outside. Examples of low-permeability substrates include recording media such as coated paper used in commercial printing, and paperboard in which waste paper pulp is blended in the middle layer and back layer and the surface is coated. When a low-permeability recording medium is used in this way, graininess deteriorates due to partial collapsing of the dots in the dots formed with the ink applied to the recording medium after applying the treatment liquid. It's easy to do. Therefore, it is preferable to use the low-absorbent recording medium and the liquid composition of the present application together, because it is possible to suppress the deterioration of graininess caused by partial collapsing of dots.

<Low permeability substrate>
Examples of the low-permeability substrate include a recording medium such as coated paper having a support and a surface layer provided on at least one side of the support, and optionally other layers. are mentioned.

In a recording medium having a support and a surface layer, the amount of pure water transferred to the recording medium at a contact time of 100 ms measured with a dynamic scanning liquid absorber is preferably 2 mL/m ² or more and 35 mL/m ² or less, and 2 mL. /m ² or more and 10 mL/m ² or less is more preferable.

If the transfer amount of the ink and pure water at a contact time of 100 ms is too small, beading may easily occur. be.

The transfer amount of pure water to the recording medium at a contact time of 400 ms measured by a dynamic scanning liquid absorption meter is preferably 3 mL/m ² or more and 40 mL/m ² or less, more preferably 3 mL/m ² or more and 10 mL/m ² or less. preferable.

If the transfer amount at a contact time of 400 ms is too small, the drying property will be insufficient, and if it is too large, the glossiness of the image area after drying may tend to be low. The amounts of pure water transferred to the recording medium at contact times of 100 ms and 400 ms can both be measured on the side of the recording medium having the surface layer.

Here, dynamic scanning absorptometer (DSA, Paper-Paper Technical Association, Vol. 48, May 1994, pp. 88-92, Shigenori Kuga) measures the amount of liquid absorbed in an extremely short time. It is a device that can accurately measure The dynamic scanning absorptive meter directly reads the speed of liquid absorption from the movement of the meniscus in the capillary. The measurement is automated by a method of automatically changing and measuring only the required number of points on one sample.

A liquid supply head to the paper sample is connected to the capillary through a Teflon (registered trademark) tube, and the position of the meniscus in the capillary is automatically read by an optical sensor. Specifically, a dynamic scanning liquid absorber (K350 series D type, manufactured by Kyowa Seiko Co., Ltd.) can be used to measure the transfer amount of pure water or ink.

The amount of transfer at a contact time of 100 ms and a contact time of 400 ms can be obtained by interpolation from measured values of the amount of transfer at contact times adjacent to each contact time.

-Support-
The support is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include sheet materials such as paper mainly composed of wood fibers and non-woven fabric mainly composed of wood fibers and synthetic fibers.
The thickness of the support is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 50 μm to 300 μm. Further, the basis weight of the support is preferably 45 g/m ² to 290 g/m ² .

-Surface layer-
The surface layer contains a pigment, a binder (binding agent) and, if necessary, a surfactant and other components.
As the pigment, an inorganic pigment or a combination of an inorganic pigment and an organic pigment can be used. Examples of inorganic pigments include kaolin, talc, heavy calcium carbonate, light calcium carbonate, calcium sulfite, amorphous silica, titanium white, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, water zinc oxide, chlorite and the like. The amount of the inorganic pigment to be added is preferably 50 parts by mass or more with respect to 100 parts by mass of the binder.
Examples of organic pigments include water-soluble dispersions of styrene-acrylic copolymer particles, styrene-butadiene copolymer particles, polystyrene particles, polyethylene particles, and the like. The amount of the organic pigment to be added is preferably 2 parts by mass to 20 parts by mass with respect to 100 parts by mass of all the pigments in the surface layer.
As the binder, it is preferable to use an aqueous resin. At least one of a water-soluble resin and a water-dispersible resin can be preferably used as the water-based resin. The water-soluble resin is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include polyvinyl alcohol, cation-modified polyvinyl alcohol, acetal-modified polyvinyl alcohol, polyester, polyurethane, and polyester and polyurethane.
Surfactants optionally contained in the surface layer are not particularly limited and can be appropriately selected depending on the intended purpose. Either can be used.
The method of forming the surface layer is not particularly limited and can be appropriately selected according to the purpose, and can be carried out by impregnating or coating the support with the liquid constituting the surface layer. ^The amount of the liquid that constitutes the surface layer is not particularly limited and can be appropriately ^{selected according} to the purpose. 15 g/m ² is more preferred.

<<Recording medium (recording material) to which treatment liquid is applied>>
The recording medium is applied with the liquid composition, and in the present application, the recording medium applied with the liquid composition is referred to as a "recording medium applied with the liquid composition" or a "recording medium". The recording medium to which the liquid composition has been applied may be a recording medium to which the liquid composition has been applied, which has been dried, or a recording medium which has not been dried and is in a wet state. It may be in the state where it is.
The recording medium to which the liquid composition is applied comprises a polyvalent metal salt, glycerin, a compound (1) having a structure obtained by addition polymerization of polyoxyethylene to diglycerin, and diglycerin to polyoxyethylene. and at least one selected from compounds (2) having a structure obtained by addition polymerization of oxypropylene. Even after the liquid composition applied to the recording medium is dried, these components remain in the recording medium to which the liquid composition has been applied.

<<Image Forming Method>>
The image forming method comprises a treatment liquid application step of applying the above liquid composition as a treatment liquid to a recording medium, and an ink application step of applying ink to a region of the recording medium to which the treatment liquid has been applied. is preferred.

<Treatment Liquid Application Process>
Methods for applying the treatment liquid to the recording medium include, for example, a liquid ejection method and a coating method.

The liquid ejection method is not particularly limited and can be appropriately selected according to the purpose. For example, a method using a charge control type head of the type.

Examples of coating methods include blade coating, gravure coating, gravure offset coating, wire bar coating, bar coating, roll coating, knife coating, air knife coating, comma coating, U comma coating, AKKU coating method, smoothing coating method, micro gravure coating method, reverse roll coating method, four or five roll coating method, dip coating method, curtain coating method, slide coating method, die coating method and the like. Among these, the wire bar coating method and the roller coating method are particularly preferred.

The treatment liquid applying step is preferably performed on a recording medium whose surface has been sufficiently dried, but may be performed on a recording medium that has been subjected to image formation and is in the process of being dried. In the treatment liquid application step, the amount of the treatment liquid applied to the recording medium is preferably 0.1 g/m ² or more and 30.0 g/m ² or less, and more preferably 0.2 g/m ² or more and 10.0 g/m ² or less. preferable. When the applied amount is 0.1 g/m ² or ^more , the image quality can be improved. can improve the drying property of the hair and prevent the occurrence of curling.

The recording medium to which the treatment liquid has been applied in the treatment liquid application step is optionally subjected to a heating step of heating the recording medium to dry the treatment liquid after the treatment liquid application step and before the ink application step described later. Although it may be carried out, the heating step may not be carried out. In the case where there is no heating step for heating the recording medium after the treatment liquid applying step and before the ink applying step, the dots formed with the ink applied to the recording medium after applying the treatment liquid may be partially Granularity is likely to deteriorate due to excessive collapse. Therefore, in the case where there is no heating step after the treatment liquid application step and before the ink application step, the use of the liquid composition of the present application suppresses deterioration of graininess due to partial collapsing of dots. It is preferable because it can
The heating step is a step of drying the treatment liquid applied to the recording medium by heating the recording medium with known heating means such as a roll heater, a drum heater, and hot air. This is the temperature at which the medium becomes 60° C. or higher.

<Ink application process>
The ink may be applied to either the recording medium before application of the treatment liquid or the recording medium after application of the treatment liquid, but may be applied to the recording medium after application of the treatment liquid. preferable. Further, it is more preferable that the ink is applied to the area of the recording medium to which the treatment liquid has been applied.
Methods for applying ink to a recording medium include an inkjet method, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, and a spray coating method. etc., but the inkjet method is preferred.

<<Image forming apparatus>>
The image forming apparatus includes a treatment liquid containing means containing the treatment liquid, a treatment liquid applying means for applying the contained treatment liquid to the recording medium, and an ink applying means for applying ink to the area to which the treatment liquid is applied. It is preferred to have means.

An embodiment of an image forming apparatus will be described with reference to FIG. FIG. 1 is a schematic diagram showing an example of an image forming apparatus.
The image forming apparatus 101 shown in FIG. 1 is an example of an ink application unit, and includes a plurality of head units 110K, 110C, 110M, and 110Y each having a plurality of heads for ejecting ink. A plurality of maintenance units 111K, 111C, 111M, and 111Y for performing maintenance, a plurality of ink cartridges 107K, 107C, 107M, and 107Y which are examples of ink storage means and which store and supply ink, and ink supplied from the ink cartridges. A plurality of sub-ink tanks 108K, 108C, 108M and 108Y store a part of the ink and supply the ink to the head at an appropriate pressure.
Further, the image forming apparatus 101 controls the conveying belt 113 that attracts and conveys the recording medium 114 by the suction fan 120, the conveying rollers 119 and 121 that support the conveying belt 113, and the conveying belt 113 so as to maintain proper tension. A tension roller 115 , a platen 124 and a platen roller 118 for maintaining appropriate flatness of the conveying belt 113 , a charging roller 116 for applying electrostatic charge for attracting the recording medium 114 , and a discharger for pressing the recording medium 114 . A paper roller 117, a paper discharge mechanism having a paper discharge tray 104 for stocking the discharged recording medium 114, a paper feed tray 103 for stocking the recording medium 114 for image formation, and recording one sheet at a time from the paper feed tray. It has separation pads 112 and 122 for sending out the medium 114, a counter roller 123 for surely attracting the sent recording medium 114 to the charging belt, and a manual feed tray 105 used when paper is fed manually.
The image forming apparatus 101 also has a waste liquid tank 109 for collecting waste liquid discharged after maintenance, and an operation panel 106 for operating the apparatus and displaying the state of the apparatus.

The nozzle arrays of the head units 110K, 110C, 110M, and 110Y are arranged perpendicular to the conveying direction of the recording medium 114, forming nozzle arrays longer than the recording area.
The recording medium 114 is separated into one sheet from the paper feed tray by a separation roller, is fixed on the transportation belt by being brought into close contact with the transportation belt by a pressure roller, and ejects droplets when passing under the head unit. As a result, an image, which is an aggregate of dots formed by liquid droplets, is formed, separated from the conveying belt by the separation claw, and discharged to the paper discharge tray supported by the paper discharge roller and the paper discharge roller. .

Further, the image forming apparatus 101 shown in FIG. 1 has a coating mechanism as a mechanism for processing the surface of the recording medium with the treatment liquid, and employs a roller coating mechanism. The processing liquid is stored in a processing liquid storage tank 135 , which is an example of a processing liquid storage unit, and is drawn up onto the roller surface by a drawing roller 137 and transferred to a film pressure control roller 138 . Subsequently, the treatment liquid transferred to the application roller 136, which is an example of the treatment liquid application unit, is transferred and applied to the recording medium 114 passed between the application counter roller 139 and the application roller 139. FIG.

The application amount of the treatment liquid transferred to the application roller 136 is controlled by controlling the nip thickness with the application roller 136 . When it is not desired to apply the treatment liquid, the movable blade 134 can be pressed against the application roller 136 so that no treatment liquid remains on the application roller 136 to scrape off the treatment liquid on the surface of the application roller. As a result, it is possible to prevent functional problems such as increase in viscosity due to dryness caused by remaining treatment liquid on the application roller 136, sticking to the application counter roller 139, and uneven application.

In addition, as shown in FIG. 1, one paper feed unit is provided on the top and bottom, and the lower paper feed unit is used when the processing liquid is applied, and the upper paper feed unit is used when the processing liquid is not applied. A method such as

In addition to the above-described roller application, it is also possible to apply the treatment liquid by a spray method. For example, a head similar to 110K can be filled with treatment liquid and ejected onto the recording medium 114 in the same manner as ink, so that ejection amount and ejection position can be controlled with high precision and ease. Further, the roller coating method and the spray coating method may be used together.
By using either method, the processing liquid can be applied in an arbitrary amount to an arbitrary position.

Further, by heating the recording medium to which the treatment liquid and the ink are adhered by the hot air blower fan 150, it is possible to improve fixability by accelerating drying. In this embodiment, the heat treatment is performed on the recording medium after printing with a hot air fan, but it may be performed on either the recording medium before image formation or after image formation. The heating may be carried out not only by a hot air fan but also by means such as a heating roller.
Further, in this embodiment, as shown in FIG. 1, there is no heating means between the ink applying means and the treatment liquid applying means in the transport path of the recording medium.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Synthesis Example of Copolymer A>
Methyl ethyl ketone was added to a reaction vessel of an automatic polymerization reactor (manufactured by Todoroki Sangyo Co., Ltd.: polymerization tester DSL-2AS type) equipped with a reaction vessel equipped with a stirring device, a dropping device, a temperature sensor, and a reflux device having a nitrogen introduction device at the top. 550 g of the mixture was charged, and the inside of the reaction vessel was replaced with nitrogen while stirring. After heating to 80° C. while maintaining the inside of the reaction vessel in a nitrogen atmosphere, 75.0 g of 2-hydroxyethyl methacrylate, 77.0 g of methacrylic acid, 80.0 g of styrene, and 150 g of butyl methacrylate were added by a dropping device. 0 g, 98.0 g of butyl acrylate, 20.0 g of methyl methacrylate, and 40.0 g of "PERBUTYL (registered trademark) O" (manufactured by NOF CORPORATION) were added dropwise over 4 hours. After the completion of dropping, the reaction was further continued at the same temperature for 15 hours to obtain a methyl ethyl ketone solution of the anionic group-containing styrene-acrylic copolymer A having an acid value of 100, a weight average molecular weight of 21,000, and a Tg (calculated value) of 31°C. got After completion of the reaction, part of the methyl ethyl ketone was distilled off under reduced pressure to obtain a copolymer A solution adjusted to have a non-volatile content of 50%.

<Preparation example of pigment dispersion>
-Preparation of Pigment Dispersion 1-
In a mixing tank equipped with a cooling jacket, 1,000 g of carbon black (trade name: Raven 1080, manufactured by Columbian Carbon Japan Co., Ltd.), 800 g of copolymer A solution, 143 g of 10% sodium hydroxide aqueous solution, methyl ethyl ketone 100 g and 1,957 g of water were charged and mixed with stirring. The mixed solution is passed through a dispersing device (manufactured by Mitsui Mining Co., Ltd.: SC Mill SC100) filled with zirconia beads with a diameter of 0.3 mm, and circulated for 6 hours by a circulation method (a method in which the dispersed liquid discharged from the dispersing device is returned to the mixing tank). dispersed. The number of rotations of the dispersing device was 2,700 rpm, and cold water was passed through the cooling jacket so as to keep the temperature of the dispersion at 40° C. or less. After completion of the dispersion, the undiluted dispersion was extracted from the mixing vessel, and then the mixing vessel and the flow path of the dispersing device were washed with 10,000 g of water. The diluted dispersion was placed in a glass distillation apparatus, and the entire amount of methyl ethyl ketone and part of the water were distilled off. After cooling to room temperature, 10% hydrochloric acid was added dropwise with stirring to adjust the pH to 4.5, and then the solid content was filtered with a Nutsche filter (manufactured by Nippon Kagaku Kikai Seisakusho, pressure filter) and washed with water. Take the cake in a container, add 200 g of a 20% aqueous potassium hydroxide solution, disperse it with Dispa (TK Homo Disper, manufactured by Tokushu Kika Kogyo Co., Ltd.), and add water to adjust the non-volatile content. A pigment dispersion 1 was obtained as composite particles dispersed in an aqueous medium, each coated with a carboxyl group-containing styrene-acrylic copolymer in which 20% by weight of carbon black was neutralized in potassium hydroxide.

-Preparation of Pigment Dispersion 2-
In the preparation of Pigment Dispersion 1, Pigment Dispersion 2 was obtained in the same manner as in Preparation Example of Pigment Dispersion 1, except that carbon black was changed to copper phthalocyanine (manufactured by Dainichiseika Kogyo Co., Ltd., SEIKALIGHT BLUE A612). rice field.

<Ink preparation example>
-Preparation of Ink 1-
22.0% by mass of glycerin, 11.0% by mass of 1,3-butanediol, 2.0% by mass of 1,3-octanediol, surfactant (trade name: E1010, manufactured by Nisshin Chemical Industry Co., Ltd.)2. 0% by mass, 2,4,7,9-tetramethyldecane-4,7-diol 1.1% by mass, Proxel LV (manufactured by Avecia) 0.1% by mass, and 2-amino-2-ethyl-1 , 0.5% by mass of 3-propanediol, and ion-exchanged water are stirred for 1 hour and mixed uniformly, and 2.0% by mass of rosin-modified maleic acid resin (manufactured by Harima Chemicals Co., Ltd.: Harimak R-100) is added. After stirring for 1 hour and mixing uniformly, Pigment Dispersion 1 was added so that the solid content was 8.0% by mass, and the mixture was further stirred for 1 hour and mixed uniformly. This mixture was subjected to pressure filtration through a polyvinylidene fluoride membrane filter having an average pore size of 0.8 μm to remove coarse particles and dust, thereby obtaining Ink 1 .

-Preparation of Inks 2-3-
Inks 2 and 3 were obtained in the same manner as Ink 1, except that the composition of Ink 1 was changed to that shown in Table 1 below. In addition, the unit of each numerical value of the composition in Table 1 is "% by mass".

<Example 1>
-Preparation of treatment liquid 1-
Glycerin 22.5% by mass, magnesium sulfate heptahydrate 25.0% (manufactured by Showa Kagaku Co., Ltd.), compound SC-E750 (manufactured by Sakamoto Co., Ltd.) having a structure in which polyoxyethylene is addition-polymerized to diglycerin 7.5 %, polyoxyalkylene alkyl ether (trade name: Emulgen 103, manufactured by Kao Corporation) 0.4% by mass, Proxel LV (manufactured by Avecia) 0.1% by mass, and benzotriazole 0.1% by mass. The mixture was stirred for hours to mix uniformly. Further, 1.2% by mass of N-octyl-2-pyrrolidone was added, and ion-exchanged water was added to make the total 100% by mass. A treatment liquid 1 was obtained.

<Examples 2 to 33, Comparative Examples 1 to 3>
-Adjustment of treatment liquids 2 to 36-
In the preparation of Treatment Liquid 1, Treatment Liquid 2, which is the liquid composition of Examples 2 to 33 and Comparative Examples 1 to 3, was prepared in the same manner as Treatment Liquid 1, except that the compositions were changed to those shown in Tables 2 to 6 below. ~36 was obtained. The unit of each numerical value of the compositions in Tables 2 to 6 is "% by mass". "SC" in Tables 2 to 6 represents the total content of compound (1) and compound (2) in the treatment liquid.

In Tables 2 to 6, the product names of ingredients and the names of manufacturers are as follows.
・SC-E450 (manufactured by Sakamoto Co., Ltd.)
・SC-E750 (manufactured by Sakamoto Co., Ltd.)
・SC-E1500 (manufactured by Sakamoto Co., Ltd.)
・SC-E2000 (manufactured by Sakamoto Co., Ltd.)
・SC-P450 (manufactured by Sakamoto Co., Ltd.)
・SC-P750 (manufactured by Sakamoto Co., Ltd.)
・ SC-P1200 (manufactured by Sakamoto Co., Ltd.)
・SC-P1600 (manufactured by Sakamoto Co., Ltd.)
・ Magnesium nitrate heptahydrate (manufactured by Showa Chemical Co., Ltd.)
・ Magnesium nitrate hexahydrate (manufactured by Showa Chemical Co., Ltd.)

Next, the treatment liquids 1 to 36 prepared in Examples 1 to 33 and Comparative Examples 1 to 3 above and the inks 1 to 3 prepared in the ink preparation examples were combined as shown in Table 7 below. Image forming sets were prepared for Examples 34 to 69 and Comparative Examples 4 to 7, and the properties of each image forming set were evaluated according to the following methods and evaluation criteria. Since Comparative Example 7 does not use the treatment liquid and uses only the ink, it is indicated as "-" in Table 7. The results are also shown in Table 7.

[Beading]
Using a wire bar (winding diameter: 0.05 mm, manufactured by Kobayashi Seisakusho Co., Ltd.), the treatment liquid is applied to the recording medium (trade name: Esprit W 210 gsm (manufactured by Nippon Paper Industries), cast coated paper) so that the coating amount is 0. .6 g/m ² was applied uniformly.
Next, the recording medium coated with the treatment liquid was ejected with ink from an image forming apparatus (device name: IPSIO GXe5500, manufactured by Ricoh Co., Ltd.) without being dried by heat treatment to obtain a print sample. A 3 cm square solid image formed of a dot pattern was used as the printing chart.
Next, the solid portion of the 3 cm square solid image formed by the dot pattern was visually observed, and the "beading property" was evaluated based on the following evaluation criteria. The case where the evaluation was B or higher was evaluated as practicable.
(Evaluation criteria)
A: No beading seen B: Some beading seen but no problem C: Beading seen and clearly visible

[Graininess]
Using a wire bar (winding diameter: 0.05 mm, manufactured by Kobayashi Seisakusho Co., Ltd.), the treatment liquid is applied to the recording medium (trade name: Esprit W 210 gsm (manufactured by Nippon Paper Industries), cast coated paper) so that the coating amount is 0. .6 g/m ² was applied uniformly.
Next, the recording medium coated with the treatment liquid was ejected with ink from an image forming apparatus (device name: IPSIO GXe5500, manufactured by Ricoh Co., Ltd.) without being dried by heat treatment to obtain a print sample. For the printing chart, a 3 cm square gradation image formed by a dot pattern with gradations was used.
Next, a 3 cm square gradation image formed by a dot pattern with gradations was visually observed, and "graininess" was evaluated based on the following evaluation criteria. The case where the evaluation was B or higher was evaluated as practicable.
(Evaluation criteria)
A: No deterioration of graininess is observed (dots are not collapsed)
B: Slight deterioration of graininess is observed, but there is no problem (most dots are not collapsed)
C: Deterioration of graininess is observed and clearly visible (most dots are collapsed)

[Precipitation]
Three petri dishes each having an inner diameter of 2.5 cm and containing 3 g of the treatment liquid were prepared and allowed to stand in an environment of 23° C. and 50% humidity. The case where the evaluation was B or higher was evaluated as practicable.
(Evaluation criteria)
A: Seven days after standing, no crystals were generated in any of the three pieces.
B: 2 days after standing, no crystals were generated in any of the 3, and 7 days after standing, crystals were generated in any of the 3. C: 2 days after standing, any of the 3. crystals form at

[Storage stability]
The treatment liquid was placed in a 20 mL glass bottle and stored in a constant temperature bath at 60° C. for two weeks. Next, using a viscometer (device name: SV-10, manufactured by A&D Co., Ltd.) at 25 ° C., the initial viscosity before storage for 2 weeks and the viscosity after storage for 2 weeks were measured. The difference between the initial viscosity before storage for a week and the viscosity after storage for 2 weeks (viscosity increase level (viscosity change rate)) was calculated, and "storage stability" was evaluated based on the following evaluation criteria. The case where the evaluation was B or higher was evaluated as preferable.
[Evaluation criteria]
A: The rate of viscosity change from the initial viscosity is less than 1% B: The rate of viscosity change from the initial viscosity is 1% or more and less than 5% C: The rate of viscosity change from the initial viscosity is 5% or more, or there are aggregates in the treatment liquid It has occurred

101 Image forming apparatus 107K, 107C, 107M, 107Y Ink cartridge 110K, 110C, 110M, 110Y Head unit 114 Recording medium 135 Treatment liquid storage tank 136 Application roller 140 Treatment liquid storage tank

JP 2011-56884 A

Claims (18)

at least one selected from a polyvalent metal salt, glycerin, a compound (1) having a structure in which polyoxyethylene is addition-polymerized to diglycerin, and a compound (2) having a structure in which polyoxypropylene is addition-polymerized to diglycerin; A liquid composition comprising: 2. The liquid composition according to claim 1, wherein said compound (1) contains a compound represented by the following general formula (1).

(In the compound represented by the general formula (1), m+n+o+p is an integer of 6 or more and 40 or less.) 3. The liquid composition according to claim 1, wherein the compound (2) contains a compound represented by the following general formula (2).

(In the compound represented by the general formula (2), q+r+s+t is an integer of 4 or more and 24 or less.) 3. The liquid composition according to claim 2, wherein in the compound represented by the general formula (1), m+n+o+p is an integer of 13 or more and 30 or less. 4. The liquid composition according to claim 3, wherein in the compound represented by the general formula (2), q+r+s+t is an integer of 9 or more and 18 or less. The mass ratio of the total content of the glycerin, the compound (1), and the compound (2) in the liquid composition to the content of the polyvalent metal salt in the liquid composition is 1.05 or more. 6. The liquid composition according to any one of claims 1 to 5, which is 1.40 or less. of the total content of the compound (1) and the compound (2) in the liquid composition relative to the total content of the glycerin, the compound (1) and the compound (2) in the liquid composition 7. The liquid composition according to any one of claims 1 to 6, wherein the mass ratio is 0.1 or more and 0.5 or less. 8. The liquid composition according to any one of claims 1 to 7, wherein the content of said polyvalent metal salt relative to the total amount of said liquid composition is 0.8 mol/kg or more and 1.4 mol/kg or less. A treatment liquid containing the liquid composition according to any one of claims 1 to 8 and applied to a recording medium. 10. An image forming method comprising: a treatment liquid application step of applying the treatment liquid according to claim 9 to a recording medium; and an ink application step of applying ink to a region of the recording medium to which the treatment liquid has been applied. 11. The image forming method according to claim 10, which does not include a heating step of heating the recording medium after the treatment liquid applying step and before the ink applying step. 12. The image forming method according to claim 10, wherein the static surface tension of the ink is 25 mN/m or less. The recording medium has a support and a coating layer provided on at least one side of the support, and is made of pure water at a contact time of 100 ms measured by a dynamic scanning absorptiometer. 13. The amount of pure water transferred to the recording medium is 2 to 35 ml/m ² and the amount of pure water transferred to the recording medium is 3 to 40 ml/m ² at a contact time of 400 ms. image forming method. 10. An image forming apparatus comprising: treatment liquid containing means containing the treatment liquid according to claim 9; and treatment liquid application means for applying the treatment liquid to the recording medium. The image forming apparatus according to claim 14, further comprising:
An image forming apparatus comprising an ink applying unit that applies ink to a region of the recording medium to which the treatment liquid has been applied. The image forming apparatus according to claim 14 or 15,
An image forming apparatus having no heating means for heating the treatment liquid applied to the recording medium. 17. The image forming apparatus according to claim 15, wherein the static surface tension of the ink is 25 mN/m or less. The recording medium has a support and a coating layer provided on at least one side of the support, and is made of pure water at a contact time of 100 ms measured by a dynamic scanning absorptiometer. 2 ml/m ² or more and 35 ml/m ² or less, and the transfer amount of pure water to the recording medium at a contact time of 400 ms is 3 ml/m ² or more and 40 ml/m ² or less. 18. The image forming apparatus according to any one of 17.

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