JP7040318B2 - Liquid composition, liquid composition applying device, image forming device, and image forming method - Google Patents

Description

The present invention relates to a liquid composition, a liquid composition applying device, an image forming device, and an image forming method.

As an ink used for applications requiring water resistance and light resistance such as posters, an ink using a coloring material such as a pigment is known. When such ink is ejected onto a low-absorbency recording medium such as coated paper used for commercial printing by an inkjet recording method, adjacent droplets coalesce on the recording medium, resulting in beading or the like. Image defects occur. As a method for eliminating image defects in beading, a method of applying a treatment liquid containing a polyvalent metal salt or the like having an action of aggregating a coloring material in the ink to a recording medium before ejecting the ink is known. ing.

Patent Document 1 discloses a liquid composition for surface treatment of a printed matter containing resin particles, water, a water-soluble salt such as a polyvalent metal salt, an organic solvent such as propylene glycol, and the like.

However, for example, when a member such as a roller comes into contact with the region of the recording medium to which the liquid composition is applied after the liquid composition is applied to the recording medium, there is a problem of adhesion to which the liquid composition adheres to the member. be. Further, when the liquid composition contains a polyvalent metal salt, there is a problem of crystallization in which crystals of the polyvalent metal salt are formed.

The invention according to claim 1 is a liquid composition containing a polyvalent metal salt, propylene glycol, and an organic solvent A having a boiling point of 260 ° C. or higher , wherein the content of the propylene glycol is the above. The content of the organic solvent A is 0.50 or more and 1.10 or less on a mass basis with respect to the content of the polyvalent metal salt, and the content of the organic solvent A is 2 on a mass basis with respect to the content of the polyvalent metal salt. It is 0.00 or more and 4.30 or less.

The liquid composition of the present invention suppresses the adhesion of the liquid composition to the member even when the member comes into contact with the region to which the liquid composition is applied, and further, the multivalent value in the liquid composition. It has an excellent effect of suppressing the crystallization of metal salts.

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

Hereinafter, an embodiment of the present invention will be described.

<< Liquid Composition >>
The liquid composition of the present embodiment preferably contains a polyvalent metal salt and an organic solvent, and if necessary, contains water and other components such as a surfactant. The organic solvent includes propylene glycol and an organic solvent having a boiling point of 250 ° C. or higher, and may contain other organic solvents as needed. The use of the liquid composition is not particularly limited, but for example, it may be a treatment liquid applied to the recording medium before the ink containing the coloring material or the like is applied to the recording medium. preferable. In the following description, the "liquid composition" may be referred to as a "treatment liquid".

<Multivalent metal salt>
When the liquid composition comes into contact with the ink, the polyvalent metal salt associates with the coloring material in the ink by a chargeable action to form an aggregate of the coloring material and separate the coloring material from the liquid phase. Promotes fixation on recording media. Further, by containing the polyvalent metal salt in the liquid composition, beading can be suppressed even if a recording medium having low ink absorption is used, and a high-quality image can be formed. Further, unlike a coagulant such as a cationic polymer, the polyvalent metal salt is a recording medium to which the liquid composition is applied after the liquid composition is applied to the recording medium until the ink is applied. Even when the member comes into contact with the region, it is possible to prevent the liquid composition from adhering to the member.

The polyvalent metal salt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a titanium compound, a chromium compound, a copper compound, a cobalt compound, a strontium compound, a barium compound, an iron compound, an aluminum compound, etc. Examples thereof include salts of calcium compounds, magnesium compounds, zinc compounds, nickel compounds and the like. These may be used alone or in combination of two or more. Among these, salts of calcium compounds, magnesium compounds, and nickel compounds are preferable, and alkaline earth metal salts of calcium compounds and magnesium compounds are more preferable, because pigments can be effectively aggregated.

The magnesium compound is not particularly limited and may 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 may 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 intended purpose. Examples thereof include barium sulfate. The zinc compound is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include zinc sulfide and zinc carbonate. The aluminum compound is not particularly limited and may be appropriately selected for the purpose, and examples thereof include aluminum silicate and aluminum hydroxide. Among these, magnesium sulfate, magnesium nitrate, calcium nitrate and the like, which have particularly high solubility in a liquid composition containing an organic solvent A having a boiling point of 250 ° C. or higher, are preferable.

Further, the polyvalent metal salt is preferably contained in an amount of 0.8 mol / L or more and 1.4 mol / L or less with respect to the total amount of the liquid composition. When it is 0.8 mol / L or more, the beading defect can be sufficiently controlled even when a recording medium having low absorbency is used, and when it is 1.4 mol / L or less, the liquid composition. Storage stability is improved.
Further, the polyvalent metal salt is preferably contained in an amount of 3.0% by mass or more, more preferably 5.5% by mass or more, and preferably 7.0% by mass or more based on the total amount of the liquid composition. More preferred. Further, the polyvalent metal salt is preferably contained in an amount of 20.0% by mass or less, more preferably 15.0% by mass or less, and 14.0% by mass or less based on the total amount of the liquid composition. More preferred. When the content of the polyvalent metal salt with respect to the total amount of the liquid composition is 3.0% by mass or more, the occurrence of beading can be further suppressed. Further, when the content is 20.0% by mass or less, it is possible to further suppress the precipitation and crystallization of the polyvalent metal salt in the liquid composition.

<Organic solvent>
The organic solvent includes propylene glycol and the organic solvent A which is an organic solvent having a boiling point of 250 ° C. or higher, and may contain other organic solvents as needed.

-Propylene glycol-
The liquid composition of this embodiment contains propylene glycol. The inclusion of propylene glycol may cause the member to come into contact with the region of the recording medium to which the liquid composition has been applied, after the liquid composition has been applied to the recording medium and before the ink is applied. However, it is possible to prevent the liquid composition from adhering to the member. This is because the liquid composition contains propylene glycol, which can reduce the tack force in the dry film formed by drying the liquid composition.
When the recording medium, which is an example of the object to which the liquid composition is applied, has low absorbency, or the surface of the member in contact with the region of the recording medium to which the liquid composition is applied is heated to 60 ° C. or higher and 100 ° C. or lower. In such cases, the liquid composition adheres significantly to the member. Therefore, it is particularly preferable to include propylene glycol in the liquid composition in such a case.

Further, propylene glycol is preferably contained in an amount of 3.0% by mass or more, more preferably 4.0% by mass or more, and further preferably 4.5% by mass or more, based on the total amount of the liquid composition. .. Further, propylene glycol is preferably contained in an amount of 15.0% by mass or less, more preferably 10.0% by mass or less, and further preferably 9.0% by mass or less, based on the total amount of the liquid composition. .. When the content of propylene glycol with respect to the total amount of the liquid composition is 3.0% by mass or more, the tacking force in the dry film formed by drying the liquid composition can be further reduced, and the liquid composition adheres to the member. It is possible to further suppress what is done.

Further, the content of propylene glycol is preferably 0.50 or more and 1.10 or less, and preferably 0.56 or more and 0.85 or less, based on the mass, with respect to the content of the polyvalent metal salt. When the content of propylene glycol is 0.50 or more with respect to the content of the polyvalent metal salt, the tacking force in the dry film formed by drying the liquid composition can be reduced, and the liquid composition can be added to the member. Can be more suppressed from adhering.

-Organic solvent A-
The liquid composition of the present embodiment contains an organic solvent A which is an organic solvent having a boiling point of 250 ° C. or higher. By containing the organic solvent A, the solubility of the polyvalent metal salt in the liquid composition can be improved, and the crystallization of the polyvalent metal salt in the liquid composition can be suppressed. The boiling point of the organic solvent A is preferably 260 ° C. or higher, more preferably 270 ° C. or lower, further preferably 280 ° C. or higher, and particularly preferably 290 ° C. or higher. Further, the boiling point of the organic solvent A is preferably 350 ° C. or lower, more preferably 300 ° C. or lower.

Examples of the organic solvent A include glycerin (boiling point: 290 ° C.), triethylene glycol (boiling point 287 ° C.), and among these, glycerin is preferable. These may be used alone or may be used in a plurality of types.

Further, the organic solvent A is preferably contained in an amount of 10.0% by mass or more, more preferably 15.0% by mass or more, and further preferably 20.0% by mass or more based on the total amount of the liquid composition. preferable. Further, propylene glycol is preferably contained in an amount of 45.0% by mass or less, more preferably 40.0% by mass or less, and further preferably 35.0% by mass or less based on the total amount of the liquid composition. .. When the content of the organic solvent A with respect to the total amount of the liquid composition is 10.0% by mass or more, the crystallization of the polyvalent metal salt in the liquid composition can be further suppressed.

Further, the content of the organic solvent A is preferably 2.00 or more and 4.30 or less, and preferably 3.00 or more and 4.30 or less, based on the mass, with respect to the content of the polyvalent metal salt. When the content of the organic solvent A is 2.00 or more with respect to the content of the polyvalent metal salt, the crystallization of the polyvalent metal salt in the liquid composition can be further suppressed.

-Other organic solvents-
The liquid composition of the present embodiment may contain other organic solvents in addition to propylene glycol and the organic solvent A which is an organic solvent having a boiling point of 250 ° C. or higher. Examples of other organic solvents include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds. Can be mentioned.
Specific examples of the water-soluble organic solvent include, for example, 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, 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, etc. Polyhydric alcohols such as alcohols, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, etc., ethylene glycol Polyhydric alcohol aryl ethers such as monophenyl ethers, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone and the like. Nitrogen-containing heterocyclic compounds, formamides, N-methylformamides, N, N-dimethylformamides, 3-methoxy-N, N-dimethylpropionamides, 3-butoxy-N, N-dimethylpropionamides and other amides, monoethanol Examples thereof include amines such as amines, diethanolamines and triethylamines, sulfur-containing compounds such as dimethylsulfoxide and thiodiethanol, propylene carbonates and ethylene carbonates.

The content of the organic solvent in the liquid composition is not particularly limited and can be appropriately selected depending on the intended purpose, but from the viewpoint of the dryness of the liquid composition, it is preferably 10% by mass or more and 60% by mass or less. , 20% by mass or more and 60% by mass or less are more preferable.

<Water>
Examples of water include ion-exchanged water, ultra-filtered water, reverse osmosis water, pure water such as distilled water, and ultrapure water. These may be used alone or in combination of two or more. The content of water is preferably 65% by mass or less, more preferably 30% by mass or more and 50% by mass or less, based on the total amount of the liquid composition. When the water content is 65% by mass or less, it is easy to suppress the increase in viscosity, gelation, precipitation of insoluble matter and the like when the water evaporates.

<Surfactant>
The surfactant has the effect of lowering the surface tension of the liquid composition, improving the wettability to various recording media, and being able to apply the liquid composition evenly. The surfactant can increase the permeation rate into various recording media by making the liquid composition moderately wet.
If the permeability of the liquid composition is low, a large amount of the liquid composition is accumulated near the surface of the recording medium, and when it comes into contact with the coloring material in the ink, the coloring material is excessively aggregated and the dot diameter is reduced, resulting in solid color. Insufficient filling of the image may occur. In addition, excessive accumulation of the coloring material on the surface of the recording medium may cause problems such as deterioration of fixability.

As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Of these, those that do not decompose even at high pH are preferable. Examples of the silicone-based surfactant include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, and side chain double-ended modified polydimethylsiloxane. Those having a polyoxyethylene group and a polyoxyethylene polyoxypropylene group as the modifying group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, 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 Si portion side chain of dimethylsiloxane.
Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because they have low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a poly having a perfluoroalkyl ether group in the side chain. Examples thereof include salts of oxyalkylene ether polymers. The counter ions of the salts in these fluorine-based surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , and NH (CH ₂ CH ₂ OH). ₃ etc. can be mentioned.
Examples of the amphoteric tenside include laurylaminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include a fatty acid ester and an ethylene oxide adduct of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, polyoxyethylene alkyl ether sulfate salt and the like.
These may be used alone or in combination of two or more.

（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 may be appropriately selected depending on the intended purpose. For example, side-chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, one-ended modified polydimethylsiloxane, side chain. Examples thereof include both-terminal modified polydimethylsiloxane, and a polyether-modified silicone-based surfactant having a polyoxyethylene group and a polyoxyethylene polyoxypropylene group as modifying groups is particularly preferable because it exhibits good properties as an aqueous surfactant. ..
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. As commercially available products, for example, they can be obtained from Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd. and the like.
The above-mentioned polyether-modified silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyalkylene oxide structure represented by the general formula (S-1) is dimethylpoly. Examples thereof include those introduced into the Si part side chain of siloxane.

(However, in the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R'represents an alkyl group.)
Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant, for example, KF-618, KF-642, KF-643 (Shinetsu Chemical Industry Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) and the like can be mentioned.

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 fluorine-based surfactant, a compound having 2 to 16 carbon atoms substituted with fluorine is preferable, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferable.
Examples of the fluorosurfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Among these, the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because it has less foaming property, and is particularly a fluorine-based compound represented by the general formula (F-1) and the general formula (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. It is an integer, or CpH _{2p + 1} and p is an integer of 1 to 19. n is an integer of 1 to 6. a is an integer of 4 to 14.
Commercially available products may be used as the above-mentioned fluorine-based surfactant. Examples of this commercially available product 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.); Full Lard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafuck F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.); 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 The Chemours Company); 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 Omniova), Unidyne DSN-403N (manufactured by Daikin Industries Co., Ltd.) Among these, FS-3100, FS-34, FS-300 manufactured by The Chemours Company, FT-110, FT-250, FT-251 manufactured by Neos Co., Ltd., FT-400S, FT-150, etc. FT-400SW, Polyfox PF-151N manufactured by Omniova Co., Ltd. and Unidyne DSN-403N manufactured by Daikin Industries Co., Ltd. are particularly preferable.

The content of the surfactant in the liquid composition is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.001% by mass or more and 5% by mass or less, preferably 0.05% by mass or more. More preferably, it is 5% by mass or less.

<Defoamer>
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because it has an excellent defoaming effect.

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

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

<pH adjuster>
The pH adjusting agent is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

<Physical characteristics of liquid composition>
The physical properties of the liquid composition are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the liquid composition at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, and more preferably 5 mPa · s or more and 25 mPa · s or less. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. As the measurement conditions, it is possible to measure at 25 ° C. with a standard cone rotor (1 ° 34'× R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes.
The surface tension of the liquid composition is preferably 35 mN / m or less, more preferably 32 mN / m or less at 25 ° C.
The pH of the liquid composition is preferably 7 to 12, more preferably 8 to 11, from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

-Tack force-
The liquid composition is applied to the cast coated paper at 23 ° C. and 65% humidity in an environment of 0.12 mg / cm ² and then heated at 80 ° C. for 15 seconds. The tack force in the region is preferably 50 mN or less, and more preferably 45 mN or less. Further, the lower the tack force is, the more preferable it is, but it may be 10 mN or more. When the tack force is 50 mN or less, the member comes into contact with the region of the recording medium to which the liquid composition is applied after the liquid composition is applied to the recording medium and before the ink is applied. Even in this case, it is possible to prevent the liquid composition from adhering to the member.

A tacking tester TAC-II (manufactured by Reska Co., Ltd.) can be used for measuring the tacking force. Further, the cast coated paper is a kind of recording medium and is a recording medium having a cast coat layer. The recording medium having a cast coat layer is a recording medium obtained by applying a paint to paper and then heating and drying it on a smooth cast drum plated with glossy chrome. Examples of commercially available cast-coated paper include Mirror Coat Gold, Mirror Coat Platinum, Double-sided Chrome Color, Esprit Coat C, Esprit Coat FP and Esprit Coat, but in this embodiment, Esprit C 157 g / Measure the tack force using m ² (manufactured by Nippon Paper Group Inc.).

The method for adjusting the tack force to 50 mN or less is not particularly limited, but for example, a method for adjusting the content of propylene glycol in the liquid composition, a method for adjusting the content of the organic solvent A in the liquid composition, and the like. A method for adjusting the mass ratio of the content of the polyvalent metal salt and the content of propylene glycol in the liquid composition, a method for adjusting the mass ratio of the content of the polyvalent metal salt and the content of the organic solvent A in the liquid composition, and the above method. In addition, a method of adjusting the type and amount of the surfactant can be mentioned. These methods may be used alone or in combination.

<< Ink >>
After the liquid composition is applied to the recording medium, the ink is applied to the area to which the liquid composition is applied, if necessary. The ink contains other components such as organic solvents, water, coloring materials, resins, and surfactants, depending on the purpose. As for other components such as water and a surfactant, the same components as those of the liquid composition can be used, and the description thereof will be omitted.

<Organic solvent>
The organic solvent used is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, 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, for example, 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, Glycolin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Examples thereof include 1,3-pentanediol and petriol.
Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether.
Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone. Can be mentioned.
Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide and the like.
Examples of amines include monoethanolamine, diethanolamine, triethylamine and the like.
Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, and thiodiethanol.
Examples of 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 lower because it not only functions as a wetting agent but also has good drying properties.

As the organic solvent, a polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of the glycol ether compound include polyhydric alcohol alkyls 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. Ethers; Examples thereof include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve the permeability of ink when paper is used as a recording medium.

The content of the organic solvent in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of ink drying property and ejection reliability. More preferably, it is 20% by mass or more and 60% by mass or less.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Further, a mixed crystal may be used as the pigment.
As the pigment, for example, a black pigment, a yellow pigment, a magenta pigment, a cyan pigment, a white pigment, a green pigment, an orange pigment, a glossy color pigment such as gold or silver, a metallic pigment, or the like can be used.
As inorganic pigments, carbon black produced by known methods such as contact method, furnace method, thermal method, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow. Can be used.
Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , Dye chelate (for example, basic dye type chelate, acid dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like can be used. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
As a specific example of the pigment, for black, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11) , Metals such as titanium oxide, and organic pigments such as aniline black (CI 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 Calcium 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 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 Greens 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.
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. Hood 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. Dilekdo Black 19,38,51,71,154,168,171,195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 can be mentioned.

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 viewpoint of improving the image density, good fixing property and ejection stability. It is as follows.

As a method of dispersing the pigment to obtain an ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersible pigment, a method of coating the surface of the pigment with a resin and dispersing it, and a method of dispersing using a dispersant are used. The method, etc. can be mentioned.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing 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) so that the pigment can be dispersed in water. Can be mentioned.
Examples of the method of coating the surface of the pigment with a resin and dispersing the pigment include a method of encapsulating the pigment in microcapsules so that the pigment can be dispersed in water. This can be rephrased as a resin-coated pigment. In this case, not all the pigments to be blended in the ink need to be coated with the resin, and the uncoated pigments or the partially coated pigments may be dispersed in the ink.
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 represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
As the dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and a naphthalene sulfonic acid Na formalin condensate can also be suitably used as the dispersant.
The dispersant may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain an ink by mixing a material such as water or an organic solvent with a pigment. It is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. It is good to use a disperser for dispersion.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose, but is 0.1% by mass from the viewpoint of obtaining good ejection stability and increasing the image density. 50% by mass or more is preferable, and 0.1% by mass or more and 30% by mass or less is more preferable.
It is preferable to degas the pigment dispersion by filtering the coarse particles with a filter, a centrifuge, or the like, if necessary.

<Resin>
The type of resin contained in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, etc. Examples thereof include resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, and acrylic silicone resins.
Resin particles made of these resins may be used. It is possible to obtain ink by mixing resin particles with a material such as a coloring material or an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more kinds of resin particles.

The volume average particle size of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining good fixability and high image hardness, 10 nm or more and 1,000 nm or less are preferable. More than 200 nm is more preferable, and 10 nm or more and 100 nm or less is particularly preferable.
The volume average particle size can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

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

The particle size of the solid content in the ink is not particularly limited and can be appropriately selected depending on the intended purpose. From the viewpoint of improving 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 in terms of the maximum number, and more preferably 20 nm or more and 150 nm or less. 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 Microtrac Bell Co., Ltd.).

<Physical characteristics of ink>
The physical characteristics of the ink are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, 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, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. As the measurement conditions, it is possible to measure at 25 ° C. with a standard cone rotor (1 ° 34'× R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less, and more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is preferably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12, and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member that comes into contact with the liquid.

<< Recording medium >>
The recording medium can be used without particular limitation, and plain paper, glossy paper, special paper, cloth and the like can be used, but it is also referred to as a low permeability recording medium or a low absorption substrate. ) Can be used particularly preferably.
The low-permeability base material means a base material having a surface having a low water permeability, absorbency, or adsorptivity, and includes a material having a large number of cavities inside but not opening to the outside. Examples of the low-permeability base material include coated paper used for commercial printing, recording media such as paperboard in which used paper pulp is blended in the middle layer and the back layer and the surface is coated. When such a low-permeability recording medium is used, the area of the recording medium to which the liquid composition is applied is applied after the liquid composition is applied to the recording medium until the ink is applied. When a member such as a roller comes into contact with the member, the liquid composition tends to adhere to the member. Therefore, it is preferable to use the liquid composition of the present application for a recording medium having low absorbency because the adhesion of the liquid composition to the member can be suppressed.

<Low permeability base material>
As the low-permeability substrate, for example, a recording medium such as coated paper having a support and a surface layer provided on at least one surface side of the support, and further having another layer as needed. Can be 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 by a dynamic scanning liquid absorbent is preferably 2 mL / m ² or more and 35 mL / m ² or less, preferably 2 mL. More preferably, it is / m ² or more and 10 mL / m ² or less.

If the transfer amount of ink and pure water at a contact time of 100 ms is too small, beading may easily occur, and if it is too large, the ink dot diameter after image formation may be too small than the desired diameter. be.

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

If the amount of transfer at a contact time of 400 ms is small, the drying property may be insufficient, and if it is too large, the gloss of the image portion after drying may be easily lowered. The amount of pure water transferred to the recording medium at contact times of 100 ms and 400 ms can be measured on the surface of the recording medium on the side having the surface layer.

Here, the dynamic scanning absorber (DSA, Paper Technology Cooperative Magazine, Vol. 48, May 1994, pp. 88-92, Shigenori Kukan) has a liquid absorption amount in an extremely short time. It is a device that can accurately measure. The dynamic scanning liquid absorber reads the speed of the liquid directly from the movement of the meniscus in the capillary, makes the sample disk-shaped, and scans the liquid-absorbing head spirally on it, and scans the speed according to a preset pattern. The measurement is automated by a method of automatically changing and measuring as many points as necessary with one sample.

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

The transfer amount at the contact time of 100 ms and the contact time of 400 ms can be obtained by interpolation from the measured values of the transfer amounts at the contact times in the vicinity of each contact time.

-Support-
The support is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paper mainly composed of wood fibers and sheet-like substances such as non-woven fabric mainly composed of wood fibers and synthetic fibers.
The thickness of the support is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 μm to 300 μm. 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 (binder), 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 the 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, and water. Examples include zinc oxide and chlorite. The amount of the inorganic pigment added is preferably 50 parts by mass or more with respect to 100 parts by mass of the binder.
Examples of the organic pigment include water-soluble dispersions such as styrene-acrylic copolymer particles, styrene-butadiene copolymer particles, polystyrene particles, and polyethylene particles. The amount of the organic pigment added is preferably 2 parts by mass to 20 parts by mass with respect to 100 parts by mass of the total pigment in the surface layer.
As the binder, it is preferable to use an aqueous resin. As the water-based resin, at least one of a water-soluble resin and a water-dispersible resin can be preferably used. The water-soluble resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyvinyl alcohol, cationically modified polyvinyl alcohol, acetal-modified polyvinyl alcohol, polyester, polyurethane, polyester and polyurethane.
The surfactant contained in the surface layer as needed is not particularly limited and may be appropriately selected depending on the intended purpose, but of anionic activators, cationic activators, amphoteric activators and nonionic activators. Both can be used.
The method for forming the surface layer is not particularly limited and may be appropriately selected depending on the intended purpose, and can be performed by impregnating or applying a liquid constituting the surface layer on the support. The amount of the liquid constituting the surface layer is not particularly limited and can be appropriately selected depending on the intended purpose. The solid content is preferably 0.5 g / m ² to 20 g / m ² and 1 g / m ² to. 15 g / m ² is more preferable.

<< Image formation method >>
The image forming method may include a liquid composition applying step of applying the above liquid composition to a recording medium, and an ink applying step of applying ink to a region to which the liquid composition of the recording medium is applied. preferable.

<Liquid composition applying process>
Examples of the method of applying the liquid composition to the recording medium include a liquid discharge method and a coating method.

The liquid discharge method is not particularly limited and can be appropriately selected according to the purpose. For example, a method using a piezoelectric element actuator, a method using thermal energy, a method using an actuator using electrostatic force, and continuous injection. Examples include a method using a type charge control type head.

Examples of the coating method include a blade coating method, a gravure coating method, a gravure offset coating method, a wire bar coating method, a bar coating method, a roll coating method, a knife coating method, an air knife coating method, a comma coating method, and a U comma coating method. Examples thereof include an AKKU coating method, a smoothing coating method, a microgravia coating method, a reverse roll coating method, a 4- to 5-roll coating method, a dip coating method, a curtain coating method, a slide coating method, and a die coating method. Among these, the wire bar coating method and the roller coating method are particularly preferable.

The amount of the liquid composition applied to the recording medium in the liquid composition application step is preferably 0.1 g / m ² or more and 30.0 g / m ² or less, and 0.2 g / m ² or more and 10.0 g / m ² or less. Is more preferable. When the applied amount is 0.1 g / m ² or more, the image quality can be improved, and when the applied amount is 30.0 g / m ² or less, the liquid composition is particularly high in the case of a recording medium having low ink absorption. The dryness of the object can be improved and the occurrence of curl can be prevented.

The recording medium to which the liquid composition is applied in the liquid composition applying step heats the recording medium after the liquid composition applying step and before the ink applying step described later to dry the liquid composition, if necessary. The heating step may be performed, but the heating step may not be performed.
The heating step is a step of heating the recording medium by a known heating means such as a roll heater, a drum heater, and warm air to dry the liquid composition applied to the recording medium, and the heating temperature by the heating means is , 60 ° C or higher, preferably 100 ° C or lower.

<Ink application process>
The ink is applied to the recording medium after the liquid composition has been applied. Ink is also applied to the area of the recording medium to which the liquid composition has been applied.
As a method of applying ink to a recording medium, 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. However, the inkjet method is preferable.

<< Image forming device >>
The image forming apparatus includes a liquid composition accommodating means in which the liquid composition is contained, a liquid composition imparting means for imparting the contained liquid composition to the recording medium, and ink in the area in which the liquid composition is imparted. It is preferable to have an ink applying means for applying the ink.

An embodiment of the 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 applying means, and corresponds to a plurality of head units 110K, 110C, 110M, 110Y in which heads for ejecting ink are integrated, and head units of the heads. A plurality of maintenance units 111K, 111C, 111M, 111Y for performing maintenance, and a plurality of ink cartridges 107K, 107C, 107M, 107Y, which are examples of ink accommodating means and accommodate and supply ink, are supplied from the ink cartridges. It has a plurality of sub ink tanks 108K, 108C, 108M, 108Y, which 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 transport belt 113 that sucks and transports the recording medium 114 by the suction fan 120, the transport rollers 119 and 121 that support the transport belt 113, and the transport belt 113 so as to maintain an appropriate tension. The tension roller 115, the platen 124 for the conveyor belt 113 to maintain appropriate flatness, the platen roller 118, the charging roller 116 for electrostatically charging the recording medium 114, and the discharge for holding the recording medium 114. A paper ejection mechanism having a paper roller 117 and a paper ejection tray 104 for stocking the ejected recording medium 114, a paper feed tray 103 for stocking an image-forming recording medium 114, and a paper feed tray for recording one sheet at a time. It has separation pads 112 and 122 for feeding the medium 114, a counter roller 123 for reliably adsorbing the sent recording medium 114 to the charging belt, and a manual feed tray 105 used when the paper is manually fed.
Further, the image forming apparatus 101 includes a waste liquid tank 109 that collects the waste liquid discharged after maintenance, and an operation panel 106 that can operate the device and display the device status.

The nozzle rows of the head units 110K, 110C, 110M, and 110Y are arranged so as to be orthogonal to the transport direction of the recording medium 114, and form a nozzle row having a length equal to or longer than the recording area.
The recording medium 114 is separated from the paper feed tray into a single sheet by a separation roller, is fixed on the transfer belt by being brought into close contact with the transfer belt by the pressure roller, and ejects droplets when passing under the head unit. By doing so, an image, which is an aggregate of dots formed by droplets, is formed, separated from the transport belt by a separating claw, and discharged to a paper ejection tray supported by a paper ejection roller and a paper ejection roller. ..

Further, the image forming apparatus 101 shown in FIG. 1 has a coating mechanism 130 which is an example of a liquid composition applying apparatus as a mechanism for treating the surface of a recording medium with a liquid composition, and employs a roller coating mechanism. .. The liquid composition is contained in a liquid composition accommodating tank 135, which is an example of the liquid composition accommodating means, is pumped up to the roller surface by the pumping roller 137, and is transferred to the membrane pressure control roller 138. Subsequently, the liquid composition transferred to the coating roller 136, which is an example of the liquid composition applying means, is transferred to the recording medium 114 passed between the coating counter roller 139 and the coating roller 139 and coated. The liquid composition applying device is a device having at least a liquid composition applying means, such as an independent device, another device, a device integrated with the means, a device incorporated in an image forming device, and the like. It may be any of.

The amount of the liquid composition transferred to the coating roller 136 is controlled by controlling the nip thickness with the coating roller 136. When it is not desired to apply the liquid composition, the movable blade 134 can be pressed against the coating roller 136 so that the liquid composition does not remain on the coating roller 136, and the liquid composition on the surface of the coating roller can be scraped off. As a result, it is possible to prevent functional disorders such as thickening due to drying caused by the liquid composition remaining on the coating roller 136, sticking to the counter roller 139 for coating, and uneven coating.

Further, as shown in FIG. 1, one paper feeding section is provided on the upper and lower sides, and the lower feeding section is provided when the liquid composition is applied, and the upper feeding section is provided when the liquid composition is not applied. You may use a method such as using it.

In addition to the roller coating, the liquid composition can also be spray-coated by a discharge method. For example, a head similar to 110K can be filled with a liquid composition and discharged to a recording medium 114 in the same manner as ink, and the ejection amount and ejection position can be controlled with high accuracy and easily. Further, the roller coating method and the spray coating method may be used in combination.
Regardless of the method, the liquid composition can be applied to an arbitrary position in an arbitrary amount.

Further, in the image forming apparatus 101 of the present embodiment, in the transport path of the recording medium 114, the liquid composition is between the position where the coating roller 136 is provided and the position where the head units 110K, 110C, 110M, 110Y are provided. The roller 200 is an example of a member that comes into direct contact with the area to which the is applied. Although the roller 200 is used for transporting the recording medium, it may be provided with a heating means for drying the liquid composition applied to the recording medium 114 by heating the liquid composition. Further, although the roller 200 itself does not have a heating means, the roller 200 may be heated by providing the heating means at a position close to the roller 200. In this embodiment, even if such an apparatus configuration is provided, it is possible to prevent the liquid composition from adhering to the roller 200. Further, the temperature on the surface of the roller 200 is preferably 60 ° C. or higher and 100 ° C. or lower. When the temperature on the surface of the roller 200 is in this range, it is possible to further suppress the liquid composition from adhering to the roller 200.

Further, by heating the recording medium to which the liquid composition and the ink are attached by the hot air blower fan 150, the fixing property can be improved by promoting the drying. In the present embodiment, the heat treatment is performed on the recording medium after printing with a hot air fan, but it may be performed on any recording medium before or after image formation, and the method thereof. This may be done not only by a hot air fan but also by a means such as a heating roller.

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

<Synthesis example of copolymer A>
Methyl ethyl ketone is placed in the reaction vessel of an automatic polymerization reaction device (manufactured by Todoroki Sangyo Co., Ltd .: polymerization tester DSL-2AS type) equipped with a reaction vessel equipped with a stirrer, a dropping device, a temperature sensor and a reflux device having a nitrogen introduction device on the upper part. 550 g was charged, and the inside of the reaction vessel was replaced with nitrogen while stirring. After warming the inside of the reaction vessel to 80 ° C while maintaining a nitrogen atmosphere, 75.0 g of -2-hydroxyethyl methacrylate, 77.0 g of methacrylic acid, 80.0 g of styrene, and 150 of butyl methacrylate were added by a dropping device. A mixed solution of 0.0 g, 98.0 g of butyl acrylate, 20.0 g of methyl methacrylate and 40.0 g of "Perbutyl (registered trademark) O" (manufactured by Nippon Oil & Fats Co., Ltd.) was added dropwise over 4 hours. After completion of the dropping, the reaction was continued at the same temperature for 15 hours to obtain a methyl ethyl ketone solution of an 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, a part of methyl ethyl ketone was distilled off under reduced pressure to obtain a copolymer A solution having a non-volatile content adjusted to 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: Raven1080, manufactured by Colombian Carbon Japan Co., Ltd.), 800 g of copolymer A solution, 143 g of 10% sodium hydroxide aqueous solution, and methyl ethyl ketone were added. 100 g and 1,957 g of water were charged and mixed by stirring. The mixed solution is passed through a dispersion device (manufactured by Mitsui Mining Co., Ltd .: SC Mill SC100) filled with zirconia beads having a diameter of 0.3 mm, and the circulation method (the method of returning the dispersion liquid from the dispersion device to the mixing tank) is used for 6 hours. Distributed. The rotation speed of the disperser was 2,700 rpm, and cold water was passed through the cooling jacket to keep the dispersion temperature at 40 ° C or lower. After the dispersion was completed, the dispersion stock solution was withdrawn from the mixing tank, and then the mixing tank and the flow path of the dispersion device were washed with 10,000 g of water to obtain a diluted dispersion solution together with the dispersion stock solution. A diluted dispersion was placed in a glass distillation apparatus, and the entire amount of methyl ethyl ketone and a part of 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 Nutche type filtration device (manufactured by Nippon Kagaku Kikai Seisakusho Co., Ltd., pressure filter) and washed with water. Take the cake in a container, add 200 g of a 20% potassium hydroxide aqueous solution, disperse it with a dispa (TK homodisper manufactured by Tokushu Kika Kogyo Co., Ltd.), and add water to adjust the non-volatile content to make it non-volatile. A pigment dispersion 1 dispersed in an aqueous medium as composite particles coated with a carboxyl group-containing styrene-acrylic copolymer in which 20% by mass of carbon black was neutralized in potassium hydroxide was obtained.

<Ink preparation example>
-Preparation of ink 1-
Glycerin (manufactured by Kanto Chemical Co., Ltd.) 22.0% by mass, 1,3-butanediol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 11.0% by mass, 2-ethyl-1,3-hexanediol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 2 .0% by mass, surfactant (trade name: E1010, manufactured by Nissin Chemical Industry Co., Ltd.) 2.0% by mass, 2,4,7,9-tetramethyldecane-4,7-diol 1.1% by mass , Proxel LV (manufactured by Abyssia) 0.1% by mass, 2-amino-2-ethyl-1,3-propanediol 0.5% by mass, and ion-exchanged water were stirred for 1 hour and mixed uniformly to modify rosin. After adding 2.0% by mass of maleic acid resin (manufactured by Harima Kasei Co., Ltd .: Harimac R-100), stirring for 1 hour and mixing uniformly, the pigment dispersion 1 is adjusted to have a solid content of 8.0% by mass. In addition, the mixture was further stirred for 1 hour and mixed uniformly. This mixture was pressure-filtered with a polyvinylidene fluoride membrane filter having an average pore size of 0.8 μm, and coarse particles and dust were removed to obtain ink 1.
The static surface tension of the obtained ink 1 was measured at 23 ° C. and 55% RH using a Wilhelmy type surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) and found to be 22 mN / m.

-Preparation of ink 2-
Ink 2 was obtained in the same manner as in the preparation of ink 1 except that the composition of ink 1 was changed to the composition shown in Table 1 below. Further, when the static surface tension was measured in the same manner as in ink 1, it was 35 mN / m. The unit of each numerical value of the composition in Table 1 is "mass%".

<Example 1>
-Preparation of liquid composition-
Glycerin (manufactured by Kanto Chemical Co., Ltd.) 22.5% by mass, propylene glycol (manufactured by ADEKA) 6.0% by mass, magnesium sulfate heptahydrate (manufactured by Showa Chemical Co., Ltd.) 22.5% by mass, 2-ethyl-1 , 3-Hexanediol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 0.2% by mass, Polyoxyalkylene alkyl ether (trade name: Emargen 103, manufactured by Kao Co., Ltd.) 0.1% by mass, 2-amino-2-ethyl-1 , 3-Propanediol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 0.3% by mass, Proxel LV (manufactured by Abyssia) 0.1% by mass, benzotriazole (manufactured by Johoku Chemical Industry Co., Ltd.) 0.1% by mass, and ion-exchanged water Was added to make a total of 100% by mass, and the mixture was stirred for 1 hour and mixed uniformly to obtain the liquid composition 1 of Example 1.

Next, the tack force of the prepared liquid composition 1 was measured. To Esprit C157 g / m ² (manufactured by Nippon Paper Group Inc.), which is cast coated paper, 0.12 mg / cm ² of liquid composition 1 was applied using a bar coater in an environment of 23 ° C. and 65% humidity. Then, after heating at 80 degrees for 15 seconds, the tack force was measured. A tacking tester TAC-II (manufactured by Reska Co., Ltd.) was used to measure the tacking force. The results are shown in Table 2.

<Examples 2 to 7, Comparative Examples 1 to 9>
-Preparation of liquid compositions 2-16-
In the preparation of the liquid composition 1, the liquid compositions 2 to 7 of Examples 2 to 7 and the comparative examples 1 to 9 are the same as the preparation of the liquid composition 1 except that the compositions are changed to the compositions shown in Tables 2 and 3 below. Liquid compositions 8 to 16 of the above were obtained. The unit of each numerical value of the composition in Tables 2 and 3 is "mass%".
Further, the tacking forces of the liquid compositions 2 to 7 of Examples 2 to 7 and the liquid compositions 8 to 16 of Comparative Examples 1 to 9 were measured in the same manner as in the liquid composition 1. The results are shown in Tables 2 and 3.
The various calculation results in Tables 2 and 3 were obtained with the molar mass of magnesium sulfate as 120.37 g / mol and the molar mass of magnesium sulfate heptahydrate as 246.47 g / mol.

In Tables 2 and 3, the product names of the ingredients and the names of the manufacturing companies are as follows.
・ Triethylene glycol (manufactured by Sankyo Chemical Co., Ltd.)
・ Ethylene glycol (manufactured by Sankyo Chemical Co., Ltd.)
・ 1,3-Propanediol (manufactured by Tokyo Chemical Industry Co., Ltd.)
・ 1,2-Butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.)

[Adhesion of liquid composition]
The adhesiveness of the liquid compositions 1 to 16 prepared in Examples 1 to 7 and Comparative Examples 1 to 9 was evaluated. To Esprit C157 g / m ² (manufactured by Nippon Paper Group Inc.), which is a cast-coated paper, 0.12 mg / cm ² of the liquid composition was applied using a bar coater in an environment of 23 ° C. and 65% humidity, and then 0.12 mg / cm 2 was applied. It was heated at 80 degrees for 15 seconds. Next, a metal plate made of aluminum at 80 ° C. was brought into contact with the region of the cast coated paper to which the liquid composition was applied while pressing at 100 kgf / m ² for 30 seconds. Then, the adhesiveness of the liquid composition to the metal plate was evaluated based on the following evaluation criteria. The results are shown in Table 4. When the evaluation was B or higher, it was evaluated as practical.
(Evaluation criteria)
A: No adhesion B: One adhesion C: Two or more adhesions

[Crystalization of liquid composition]
The crystallization of the liquid compositions 1 to 16 prepared in Examples 1 to 7 and Comparative Examples 1 to 9 was evaluated. 3.0 g of the liquid composition was placed in a petri dish having a diameter of 27 mm and without a lid, and allowed to stand in an environment of room temperature of 24 ° C. and humidity of 44% until crystals were formed. The crystallization of the liquid composition was evaluated based on the following evaluation criteria. The results are shown in Table 4. When the evaluation was B or higher, it was evaluated as practical. In addition, "crystals are generated" means that a visible crystal is generated, and for example, a crystal having a length of the longest portion of 0.1 mm or more is generated.
(Evaluation criteria)
A: Time to crystallize 200 hours or more B: Time to crystallize 100 hours or more, less than 200 hours C: Time to crystallize less than 100 hours

[Beading]
The beading property in the image formed by using the inks 1 and 2 prepared above, and the liquid compositions 1 to 16 prepared in Examples 1 to 7 and Comparative Examples 1 to 9 was evaluated. First, 0.12 mg / cm ² of the liquid composition was applied to Esprit C157 g / m ² (manufactured by Nippon Paper Group Inc.), which is cast coated paper, in an environment of 23 ° C. and 65% humidity using a bar coater. .. Next, the ink produced above was filled in an inkjet printer (device name: IPSiO GXe5500, manufactured by Ricoh Co., Ltd.), a solid image was printed on the area of the recording medium to which the liquid composition was applied, and the temperature was 80 ° C. for 2 minutes. It was dried by heating. The uneven density (beading) of the solid image was observed with an optical microscope at a magnification of 40 times, and evaluated based on the following evaluation criteria. The results are shown in Table 5. A case where the evaluation was B or higher was evaluated as practically preferable.
(Evaluation criteria)
A: No beading observed B: Slight beading observed C: Significant beading observed

101 Image forming device 107K, 107C, 107M, 107Y Ink cartridge 110K, 110C, 110M, 110Y Head unit 114 Recording medium 130 Coating mechanism 135 Liquid composition storage tank 136 Coating roller 200 Roller

JP-A-2017-222833

Claims (13)

A liquid composition containing a polyvalent metal salt, propylene glycol, and an organic solvent A, which is an organic solvent having a boiling point of 260 ° C. or higher .
The content of the propylene glycol is 0.50 or more and 1.10 or less on a mass basis with respect to the content of the polyvalent metal salt.
The content of the organic solvent A is 2.00 or more and 4.30 or less on a mass basis with respect to the content of the polyvalent metal salt. The liquid composition according to claim 1, wherein the organic solvent A contains either glycerin or triethylene glycol . The liquid composition according to claim 1 or 2, wherein the content of the polyvalent metal salt is 5.5% by mass or more and 14.0% by mass or less with respect to the total amount of the liquid composition. The liquid composition according to any one of claims 1 to 3, wherein the content of the propylene glycol is 0.56 or more and 0.85 or less on a mass basis with respect to the content of the polyvalent metal salt. The liquid composition according to any one of claims 1 to 4, wherein the content of the organic solvent A is 3.00 or more and 4.30 or less on a mass basis with respect to the content of the polyvalent metal salt. .. A liquid composition that is applied to the recording medium before the ink is applied to the recording medium.
The liquid composition is the liquid composition according to any one of claims 1 to 5 . A liquid composition applying device comprising the liquid composition accommodating means for accommodating the liquid composition according to any one of claims 1 to 6 and the liquid composition applying means for applying the liquid composition to a recording medium. .. A liquid composition accommodating means for accommodating the liquid composition according to any one of claims 1 to 6 , a liquid composition applying means for imparting the liquid composition to a recording medium, and the liquid composition of the recording medium. An image forming apparatus having an ink applying means for applying ink to an area to which an object is applied. The liquid composition is applied between the position where the liquid composition applying means is provided and the position where the ink applying means is provided in the transport path of the recording medium of the image forming apparatus according to claim 8. An image forming apparatus having a member in contact with a region. The image forming apparatus according to claim 9, wherein the member is a roller. The image forming apparatus according to claim 9 or 10, wherein the surface temperature of the member is 60 ° C. or higher and 100 ° C. or lower. The recording medium has a support and a coating layer provided on at least one surface side of the support, and the recording medium of pure water having a contact time of 100 ms measured by a dynamic scanning liquid absorbent meter. 8 to claim 8 to which the amount of transfer to the recording medium is 2 ml / m ² or more and 35 ml / m ² or less, and the amount of pure water transferred 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. 11. The image forming apparatus according to any one of items 11. A liquid composition applying step of applying the liquid composition according to any one of claims 1 to 6 to a recording medium, and an ink applying step of applying ink to a region to which the liquid composition is applied. Image forming method having.

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