JP2020019183A - Set for image formation, image formation device and image formation method - Google Patents

Abstract

To provide a set for image formation capable of suppressing generation of beading, and preventing generation of curl.SOLUTION: There is provided a set for image formation having a recording medium and a treatment liquid added to the recording medium, in which the treatment liquid contains a polyvalent metal salt, and satisfies relations of 59≥A≥50 mN/m, 27≤B≤38 mN/m, 2.1≥A/B≥1.5 as relations between dynamic surface tension (A) of 15 ms and static surface tension (B), and the recording medium and the treatment liquid satisfy a relation of 1.5≤(Vi/Vr)≤2.5 as a relation of roughness index calculated by a Bristow method and liquid absorption amount Vi of 20 ms.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming set, an image forming apparatus, and an image forming method.

  The ink jet recording method is a method in which a small amount of ink droplets fly from a fine nozzle and adhere to a recording medium such as paper to record characters and images, and have low noise, a simple process, and easy colorization. Therefore, it is widely used as a home printer.

  In recent years, the ink jet recording method has been expanding as commercial printing because of its advantages such as variable printing and compatibility with a wide range of media. In commercial printing, printing is performed on various types of paper, and the paper is roughly divided into plain paper and coated paper. However, ensuring the optical density (OD) of plain paper and ensuring the gloss of coated paper differ in the required ink function. Therefore, in image formation, color reproducibility of image, abrasion resistance, durability, light resistance, image drying property, character bleed (feathering), color boundary bleed (color bleed), beading, double-sided printability, ejection It is very difficult to satisfy all the required properties such as stability, and the ink to be used is selected according to the characteristics that are prioritized according to the application.

Therefore, by applying a processing liquid having a function of aggregating a coloring material onto a recording medium in advance, and ejecting ink on the recording medium for printing, the image density and saturation of plain paper and coated paper can be increased. There has been proposed an ink jet recording method capable of performing the following.
For example, in Japanese Patent Application Laid-Open No. H11-163, for the purpose of preventing the occurrence of cockling of a recording material and the like, a treatment liquid having a specific viscosity is applied to a coated paper by a Bristow method and the roughness index Vr and absorption of the coated paper are measured. An ink jet recording method is disclosed in which, based on an index of a transition amount Vi at a bending point where a coefficient value changes, the ink is applied to the coated paper after being applied by a roll coating method.

  However, in the method disclosed in Patent Literature 1, the processing liquid does not uniformly wet and spread on the rollers and the coated paper, and the coagulant contained in the processing liquid is unevenly present on the coated paper. However, there is a problem that unevenness can be seen.

  In addition to the technology disclosed in Patent Document 1, a recording medium having a surface coated with a white pigment or a water-soluble polymer has been proposed. However, this proposal is expensive because it requires special processing on the recording medium, and is limited to special uses such as photographic image output, and has not been widely used.

  On the other hand, according to the study of the present inventors, it has been found that when the treatment liquid and the ink penetrate into the recording medium, the coloring is deteriorated and beading occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming set capable of suppressing beading and curling.

The above problem is solved by the following configuration 1).
1) An image forming set comprising a recording medium and a treatment liquid applied to the recording medium, wherein the treatment liquid contains a polyvalent metal salt, and has a dynamic surface tension (A) of 15 ms and a static The relationship between the target surface tension (B) satisfies the relationship of 59 ≧ A ≧ 50 mN / m, 27 ≦ B ≦ 38 mN / m, 2.1 ≧ A / B ≧ 1.5, and the recording medium and the treatment liquid Is a set for image formation, which satisfies the relationship of 1.5 ≦ (Vi / Vr) ≦ 2.5 as the relationship between the roughness index Vr obtained by the Bristow method and the liquid absorption Vi of 20 ms ^0.5 .

  According to the present invention, it is possible to provide an image forming set capable of suppressing the occurrence of beading and preventing the occurrence of curling.

FIG. 1 is an explanatory perspective view showing an example of the ink jet recording apparatus. FIG. 2 is a perspective explanatory view showing an example of a main tank in the ink jet recording apparatus.

  The present inventors have conducted intensive studies and found that the degree of penetration of the treatment liquid into the recording medium greatly affected beading, curling and cockling of the recording medium, and to prevent these adverse effects, It is effective to set the type of coagulant in the processing liquid, the relationship between the dynamic surface tension and the static surface tension of the processing liquid, the roughness of the recording medium, and the absorption amount of the processing liquid to the recording medium in specific ranges. It was found that.

Based on the above knowledge, the image forming set of the present invention needs to have a recording medium and a treatment liquid applied to the recording medium, and satisfy all of the following conditions (1) to (3).
(1) The treatment liquid contains a polyvalent metal salt.
(2) The treatment liquid has a dynamic surface tension (A) of 15 ms and a static surface tension (B) of 59 ≧ A ≧ 50 mN / m, 27 ≦ B ≦ 38 mN / m, 2.1 ≧ A / The relationship of B ≧ 1.5 is satisfied.
(3) The recording medium and the treatment liquid satisfy the relationship of 1.5 ≦ (Vi / Vr) ≦ 2.5 as the relationship between the roughness index Vr obtained by the Bristow method and the liquid absorption Vi of 20 ms ^0.5 .

  The image forming set of the present invention satisfies all of the above-mentioned conditions (1) to (3) to ensure a sufficient amount of the processing liquid immediately after being applied onto the surface of the recording medium, and to allow the processing liquid to elapse over time. , The cohesion of the colorant of the ink can be increased with a small amount of application, and the occurrence of beading can be suppressed. In addition, since the aggregation of the coloring material of the ink is completed before the treatment liquid permeates the recording medium, curling and cockling of the recording medium can be suppressed.

  The treatment liquid used in the present invention contains a polyvalent metal salt as a flocculant. Further, the treatment liquid preferably contains an organic solvent and water, and may contain a surfactant, an antifoaming agent, a pH adjusting agent, an antiseptic / antifungal agent, a rust inhibitor and the like as required. Organic solvents, surfactants, defoamers, pH adjusters, preservatives and fungicides, and rust inhibitors can be the same as those used for the inks described below, and are used in other known processing liquids. Material can be used.

  In particular, when the treatment liquid contains a water-soluble organic solvent, it has an effect of suppressing water evaporation and suppressing precipitation of metal salts. In this embodiment, the content of the water-soluble organic solvent in the treatment liquid is preferably from 10% by mass to 50% by mass, and more preferably from 20% by mass to 40% by mass.

  Further, when the treatment liquid contains a surfactant, there is an effect that the treatment liquid can be uniformly applied onto the recording medium. In this embodiment, the content of the surfactant contained in the treatment liquid is preferably 5% by mass or less at which the surfactant is not separated.

The polyvalent metal salt can be composed of a specific polyvalent metal ion having two or more valences and an anion binding to the polyvalent metal ion. Examples of the salt include a calcium salt, a magnesium salt, a nickel salt, an aluminum salt, a boron salt, a zinc salt and the like, preferably a calcium salt and a magnesium salt, and more preferably a magnesium salt. In addition, the polyvalent metal salt contained in the treatment liquid need not be one kind, and may be composed of two or more kinds.
Specific examples of the polyvalent metal salt include the following inorganic metal salts and organic acid metal salts.

Examples of the inorganic metal salt include calcium chloride, magnesium chloride, calcium bromide, magnesium bromide, calcium nitrate, magnesium nitrate, magnesium sulfate and the like.
Examples of the organic acid metal salts include calcium salts and magnesium salts of pantothenic acid, propionic acid, ascorbic acid, acetic acid, and lactic acid.

  The content of the polyvalent metal salt in the treatment liquid is, for example, 10 to 40% by mass, and preferably 15 to 30% by mass.

The processing liquid in the present invention has a relation of dynamic surface tension (A) of 15 ms and static surface tension (B) of 59 ≧ A ≧ 50 mN / m, 27 ≦ B ≦ 38 mN / m, and 2.1 ≧ A / B. Satisfies the relationship of ≧ 1.5. By setting the dynamic surface tension (A) of 15 ms to 50 mN / m or more, it is possible to suppress the penetration of the treatment liquid into the recording medium. Can be applied uniformly.
Further, by setting the static surface tension (B) to 27 mN / m or more, it is possible to leave the coagulant component uniformly on the recording medium. Can be evenly spread and spread.

The dynamic surface tension (A) of 15 ms is a value measured by the maximum bubble pressure method at a temperature of 25 ° C. and a bubble life time of 15 ms. can do.
The static surface tension (B) can be measured at a temperature of 25 ° C. using a surface tension meter DY300 (manufactured by Kyowa Interface Co., Ltd.).

The method for adjusting the dynamic surface tension (A) in the treatment liquid is not particularly limited. For example, it can be controlled to a desired value by appropriately changing the type and amount of the surfactant added to the treatment liquid.
The method for adjusting the static surface tension (B) in the treatment liquid is not particularly limited. For example, a desired value can be obtained by appropriately changing the kind and amount of the diol added to the treatment liquid and the kind and amount of the surfactant. Can be controlled.

Further, the recording medium and the processing liquid in the present invention need to satisfy the relation of 1.5 ≦ (Vi / Vr) ≦ 2.5 as the relation between the roughness index Vr obtained by the Bristow method and the liquid absorption Vi of 20 ms ^0.5. is there. By setting (Vi / Vr) to 1.5 or more, it becomes possible to suppress the absorption of the processing liquid irrespective of the type of the recording medium and leave the aggregated component on the recording medium. In addition, it is possible to suppress the extra processing liquid from entering the inside of the recording medium, and it is possible to prevent curling and cockling.

  What is the Bristow method? 51-87, "Method for Testing Liquid Absorbency of Paper and Paperboard" and is well known. Both the roughness index and the liquid absorption by the Bristow method are measured using a recording medium to be printed and a processing liquid to be used.

From the viewpoint of improving the effect of the present invention, the relationship between the roughness index Vr determined by the Bristow method and the liquid absorption Vi at 20 ms ^0.5 is preferably 1.8 ≦ (Vi / Vr) ≦ 2.5, and 1.9 ≦ (Vi / Vr). More preferably, (Vi / Vr) ≦ 2.2.

In order to adjust the relationship between the roughness index Vr and the liquid absorption amount Vi to the above range, a method of adjusting the blending amounts of the water-soluble organic solvent and the surfactant to be used can be mentioned.
The amount of the pretreatment liquid applied to the recording medium is, for example, 10 mg to 80 mg / A4, and preferably 20 mg to 60 mg / A4.

  The image forming set of the present invention can include ink. Hereinafter, the ink used in the present invention will be described.

<Ink>
Hereinafter, organic solvents, water, coloring materials, resins, additives, and the like used in the ink will be described.

<Organic solvent>
The organic solvent used in the present invention 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 the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 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-he Polyhydric alcohols such as sundiol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, ethylene glycol mono Polyhydric alcohol alkyl ethers such as ethyl 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, ethylene glycol monophenyl ether, ethylene glycol mono Polyhydric alcohol aryl ethers such as benzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- Nitrogen-containing heterocyclic compounds such as -pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, Amides such as N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide; amines such as monoethanolamine, diethanolamine and triethylamine; sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol; 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.

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, 2,2,4-trimethyl-1,3-pentanediol, and the like.
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; 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 ink permeability 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. The content is more preferably from 20% by mass to 60% by mass.

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of drying properties and ejection reliability of the ink, the content is preferably from 10% by mass to 90% by mass, and more preferably from 20% by mass. % To 60% by mass is more preferable.

<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, for example, black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, luster pigments such as gold and silver, and metallic pigments can be used.
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 a known method such as a contact method, a furnace method, and a thermal method Can be used.
Examples of the organic pigment 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, quinoflurone pigments). And dye chelates (eg, basic dye chelates and acid dye chelates), nitro pigments, nitroso pigments, aniline black, and the like. Among these pigments, those having good affinity for the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can be used.
Specific examples of the pigment include carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, or copper or iron (CI pigment black 11) for black. And 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 Carmine 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 Green 1, 4, 7, 8, 10, 17, 18, 36, and the like.
The dye is not particularly limited, and an acidic dye, a direct dye, a reactive dye, and a basic dye can be used. One type of dye may be used alone, or two or more types may be used in combination.
Examples of the dye include 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. 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 as follows.

In order to disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of coating and dispersing the surface of the pigment with a resin, a method of dispersing using a dispersant, And the like.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersible pigment, for example, a self-dispersible pigment which can be dispersed in water by adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon). Can be used.
As a method of coating and dispersing the surface of the pigment with a resin, a method in which the pigment is included in microcapsules and can be dispersed in water can be used. This can be rephrased as a resin-coated pigment. In this case, it is not necessary that all the pigments incorporated in the ink be coated on the resin, and as long as the effects of the present invention are not impaired, uncoated pigments or partially coated pigments are dispersed in the ink. May be.
Examples of a method of dispersing using a dispersant include a method of dispersing using a known low-molecular type dispersant and a high-molecular type dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, or the like can be used depending on the pigment.
RT-100 (a nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd., and Na formalin condensate of naphthalenesulfonic acid can also be suitably used as the dispersant.
One type of dispersant may be used alone, or two or more types may be used in combination.

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

<Resin>
The type of the resin contained in the ink is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a urethane resin, a polyester resin, an acrylic resin, a vinyl acetate resin, a styrene resin, and a butadiene resin. Resin, styrene-butadiene-based resin, vinyl chloride-based resin, acrylic styrene-based resin, acrylic silicone-based resin, and the like.
Resin particles made of these resins may be used. Ink can be obtained by mixing resin particles with a material such as a coloring material or an organic solvent in a state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, appropriately synthesized ones or commercially available ones may be used. These may be used alone or in combination of two or more 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, it is preferably from 10 nm to 1,000 nm, and preferably from 10 nm to 1,000 nm. The thickness is more preferably from 200 nm to 200 nm, and particularly preferably from 10 nm to 100 nm.
The volume average particle size can be measured, for example, using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Inc.).

  The content of the resin is not particularly limited and may be appropriately selected depending on the purpose. 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 preferably 5% by mass or more and 20% by mass or less.

<Additives>
If necessary, a surfactant, an antifoaming agent, an antiseptic / antifungal agent, a rust inhibitor, a pH adjuster and the like may be added to the ink.

<Surfactant>
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 can be appropriately selected depending on the purpose. Among them, those which do not decompose even at a high pH are preferable, and examples thereof include side-chain-modified polydimethylsiloxane, both-end-modified polydimethylsiloxane, one-end-modified polydimethylsiloxane, and both-chain-end both-end modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. In addition, a polyether-modified silicone-based surfactant can also be used as the silicone-based surfactant, 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 the fluorine-based surfactant include a perfluoroalkylsulfonic acid compound, a perfluoroalkylcarboxylic acid compound, a perfluoroalkylphosphate ester compound, a perfluoroalkylethylene oxide adduct, and a perfluoroalkylether group in a side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid and perfluoroalkylsulfonic 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 a side chain include a sulfate salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in a side chain, and having a perfluoroalkyl ether group in a side chain. Salts of a polyoxyalkylene ether polymer are exemplified. The counter ions of the salts in these fluorinated 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 and the} like.
Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, and the like.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurylate, and polyoxyethylene alkyl ether sulfate.
These may be used alone or in combination of two or more.

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

(In the formula (S-1), m, n, a, and b represent an integer. R and R 'represent an alkyl group or an alkylene group.)
Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant. For example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical 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, and TSF4453 (Toshiba Silicon Co., Ltd.).

  The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the purpose. However, from the viewpoint of excellent wettability and ejection stability and improved image quality, 0.001 mass % To 5% by mass, more preferably 0.05% to 5% by mass.

<Defoaming agent>
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, silicone-based antifoaming agents are preferred because of their excellent foam breaking effect.

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

<Rust inhibitor>
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 the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

The physical properties of the ink are not particularly limited and can be appropriately selected depending on the 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, and more preferably 5 mPa · s or more and 25 mPa · s or less, from the viewpoint of improving 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 measurement conditions, measurement can be performed at 25 ° C. with a standard cone rotor (1 ° 34 ′ × R24), a sample liquid amount 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, more preferably 32 mN / m or less at 25 ° C., from the viewpoint that the ink is suitably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably from 7 to 12, and more preferably from 8 to 11, from the viewpoint of preventing corrosion of the metal member that comes into contact with the ink.

<Recording medium>
The recording medium used for recording is not particularly limited, and examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper.

<Image forming method and image forming apparatus>
The image forming method of the present invention includes a step of applying the processing liquid on a recording medium, and a step of applying ink to the recording medium to which the processing liquid has been applied. The apparatus includes means for applying a processing liquid onto a recording medium, and means for applying ink to the recording medium to which the processing liquid has been applied.
In order to apply the treatment liquid on the recording medium in the present invention, a known pretreatment device can be used. For example, as one mode of the pretreatment device, as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), a liquid storage unit having a pretreatment liquid and a liquid ejection head Is added, and the pretreatment liquid is discharged by an ink jet recording method.
As another embodiment of the pretreatment device, there is an embodiment in which a pretreatment device other than the ink jet recording method, for example, a blade coating method, a roll coating method, or a spray coating method is provided.
Next, a recording apparatus and a recording method of the ink (also referred to as the ink of the present invention) will be described.

<Recording device and recording method>
The ink of the present invention can be suitably used in various recording apparatuses using an ink jet recording system, for example, a printer, a facsimile apparatus, a copying apparatus, a combined printer / fax / copier machine, and a three-dimensional printing apparatus.
In the present application, a recording device and a recording method are a device capable of discharging ink, various processing liquids, and the like to a recording medium, and a method of performing recording using the device. The recording medium means a medium to which ink and various processing liquids can be temporarily attached.
This recording apparatus can include not only a head portion for discharging ink, but also means for feeding, transporting, and discharging a recording medium, and other devices such as a pre-processing device and a post-processing device. .
The recording device and the recording method may include a heating unit used in the heating step and a drying unit used in the drying step. The heating means and the drying means include, for example, means for heating and drying the printing surface or the back surface of the recording medium. The heating means and the drying means are not particularly limited, and for example, a warm air heater or an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording apparatus and the recording method are not limited to those in which a significant image such as a character or a graphic is visualized by ink. For example, those that form a pattern such as a geometric pattern and the like that form a three-dimensional image are also included.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise limited.
Furthermore, this recording apparatus can use not only a desktop type but also a wide recording apparatus that can print on an A0 size recording medium, or a continuous paper wound in a roll shape as a recording medium. It also includes a simple continuous printer.
An example of the recording apparatus will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective explanatory view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanism section 420 is provided inside an exterior 401 of the image forming apparatus 400. Each ink storage section 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is packaged with, for example, an aluminum laminate film. It is formed by a member. The ink storage unit 411 is stored in a storage container case 414 made of, for example, plastics. Thus, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided behind the opening when the cover 401c of the apparatus main body is opened. The main tank 410 is detachably mounted on the cartridge holder 404. Accordingly, the ink discharge ports 413 of the main tank 410 and the discharge heads 434 for the respective colors communicate with each other via the supply tubes 436 for the respective colors, and the ink can be discharged from the discharge heads 434 to the recording medium.

  Further, image forming, recording, printing, printing and the like in the terms of the present invention are all synonyms.

  Hereinafter, examples and comparative examples of the present invention will be described, but the present invention is not limited to these. In addition, the amount (%) of each component described in Examples is a solid content on a mass basis unless otherwise specified.

(Preparation of treatment liquid)
Each component was mixed and stirred at the ratios (mass basis) shown in Tables 1 and 2 below to obtain various treatment liquids.

(Measurement of dynamic surface tension (A) and static surface tension (B) of treatment liquid)
The dynamic surface tension (A) and the static surface tension (B) of the treatment liquid were measured by the method described above. The results are shown in Tables 1 and 2.

(Measurement of roughness index Vr and liquid absorption Vi)
According to the method described above, the roughness index Vr and the liquid absorption Vi of the treatment liquid were measured. The results are shown in Tables 1 and 2.
The coating of the treatment liquid on the recording medium was performed using a wire bar (winding diameter: 0.02 mm) manufactured by Kobayashi Seisakusho at a coating amount of 40 mg / A4 before printing, and then at 90 ° C. for 30 seconds. Oven drying was performed.
Immediately after oven drying, printing using the ink was performed and subjected to the following test.

  The ink formulation is as follows.

(Preparation Example 1)
-Preparation of black pigment dispersion-
90 g of carbon black (MA100, manufactured by Mitsubishi Chemical Corporation) was added to 3,000 mL of a 2.5 N sodium sulfate solution, stirred at a temperature of 60 ° C. and a speed of 300 rpm, and reacted for 10 hours to perform an oxidation treatment. The obtained reaction solution was filtered, the filtered carbon black was neutralized with a sodium hydroxide solution, and ultrafiltration was performed. The obtained carbon black was washed with water, dried, and dispersed in pure water so that the pigment concentration became 20%. Thus, the black pigment dispersion of Preparation Example 1 was prepared.

(Preparation Example 2)
-Preparation of yellow pigment dispersion-
C.I. I. Pigment Yellow 128 was subjected to low-temperature plasma treatment to prepare a yellow pigment having a carboxylic acid group introduced therein. This was dispersed in ion-exchanged water and desalted and concentrated by an ultrafiltration membrane to obtain a yellow pigment dispersion of Preparation Example 2 having a pigment concentration of 15%.

(Preparation Example 3)
-Preparation of magenta pigment dispersion-
C. I. Pigment Yellow 128 instead of C.I. I. A surface-modified magenta pigment was produced in the same manner as in Preparation Example 2 except that Pigment Red 122 was used. This was dispersed in ion-exchanged water and desalted and concentrated by an ultrafiltration membrane to obtain a magenta pigment dispersion of Preparation Example 3 having a pigment concentration of 15%.

(Preparation Example 4)
-Preparation of cyan pigment dispersion-
C. I. Pigment Yellow 128 instead of C.I. I. A surface-modified cyan pigment was produced in the same manner as in Preparation Example 2 except that Pigment Cyan 15: 3 was used. This was dispersed in ion-exchanged water and desalted and concentrated by an ultrafiltration membrane to obtain a cyan pigment dispersion of Preparation Example 4 having a pigment concentration of 15%.

An ink composition having the following formulation was prepared, and then filtered with a membrane filter having an average pore diameter of 0.8 μm to prepare each ink.
(Ink composition)
・ 20.00% of pigment dispersion obtained in each preparation example
・ 1,3-butanediol 23.00%
・ Glycerin 8.00%
・ 2-ethyl-1,3-hexanediol 2.00%
-Proxel LV 0.20% (Avisia, fungicide)
-2-amino-2-ethyl-1,3-propanediol 0.30%
・ Superflex (urethane resin, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10.00%
・ Capstone FS-30 (manufactured by Dupont) 1.00% (0.80% for black)
・ Remaining amount of ion-exchanged water (total: 100%)

<Evaluation>
<Beading>
Using Ricoh's IPSIO GXe5500 as an image forming device and Stora Enso's Lumi Art Gross130 as a recording medium, selecting glossy paper-clean mode, no color correction, printing a solid image, and density unevenness (beading) Was visually determined.
[Evaluation criteria]
AA: None at all.
A: Density unevenness can be slightly confirmed from a position 15 cm away.
B: Density unevenness can be slightly observed from a distance of 30 cm.
C: Density unevenness can be confirmed even at a distance of 1 m.
D: Density unevenness can be confirmed even from a distance of 1.5 m or more.

<Curl>
The treatment liquid was applied on Lumi Art Gross130, and without drying, the sheet was placed on a horizontal table, and after 30 seconds, the height of the sheet at the maximum distance vertically from the table was measured.
[Evaluation criteria]
A: 0 to 3 mm.
B: higher than 3 mm and 5 mm or less.
C: higher than 5 mm and 10 mm or less.
D: higher than 10 mm.

The evaluation of beading is equal to or higher than B judgment, and the evaluation of curl is equal to or higher than B judgment, which is a level that does not cause any problem in actual use.
The results are shown in Tables 1 and 2.

  In Tables 1 and 2, Himax SC-506 is a polyalkylamine-based cationic polymer manufactured by Hymo Co., Ltd., and Capstone-FS3100 and Capstone-FS34 are nonionic fluorine-containing surfactants manufactured by Chemers Co., Ltd. LS-106 is a polyoxyalkylene alkyl ether manufactured by Kao Corporation, and WET-270 is a polyether-modified silicone-based surfactant manufactured by Shin-Etsu Chemical Co., Ltd.

From the results shown in Tables 1 and 2, the treatment liquids of the respective examples contain a polyvalent metal salt and have a relationship between a dynamic surface tension (A) of 15 ms and a static surface tension (B) of 59 ≧ A ≧ 50 mN / m, 27 ≦ B ≦ 38 mN / m, 2.1 ≧ A / B ≧ 1.5, and the recording medium and the processing liquid have a roughness index Vr determined by the Bristow method and a roughness index Vr of 20 ms ^0.5 . Since the relationship of 1.5 ≦ (Vi / Vr) ≦ 2.5 is satisfied as the relationship of the liquid absorption amount Vi, the occurrence of beading is suppressed and the occurrence of curl is also reduced at the same time as compared with the processing solution of the comparative example. It was shown to be preventable.

400 Image forming apparatus 401 Exterior of image forming apparatus 401c Cover of apparatus main body 404 Cartridge holder 410 Main tank 410k, 410c, 410m, 410y For each color of black (K), cyan (C), magenta (M), yellow (Y) Main tank 411 ink storage section 413 ink discharge port 414 storage container case 420 mechanism section 434 discharge head 436 supply tube

Japanese Patent No. 5513031

Claims (8)

An image forming set comprising a recording medium and a treatment liquid applied to the recording medium, wherein the treatment liquid contains a polyvalent metal salt, and has a dynamic surface tension (A) of 15 ms and a static surface tension. As the relationship of the tension (B), the relationship of 59 ≧ A ≧ 50 mN / m, 27 ≦ B ≦ 38 mN / m, 2.1 ≧ A / B ≧ 1.5 is satisfied, and the recording medium and the processing liquid are: An image forming set characterized by satisfying a relationship of 1.5 ≦ (Vi / Vr) ≦ 2.5 as a relationship between a roughness index Vr obtained by the Bristow method and a liquid absorption Vi of 20 ms ^0.5 .   2. The image forming set according to claim 1, wherein the polyvalent metal salt in the processing liquid contains one of a magnesium salt and a calcium salt.   The image forming set according to claim 1, wherein the content of the polyvalent metal salt in the processing liquid is 10% by mass or more and 40% by mass or less.   The treatment liquid contains a water-soluble organic solvent, and the content of the water-soluble organic solvent contained in the treatment liquid is 10% by mass or more and 50% by mass or less. An image forming set according to any one of the above.   The image forming set according to any one of claims 1 to 4, wherein the processing liquid contains a surfactant, and the surfactant contained in the processing liquid is 5% by mass or less.   The image forming set according to claim 1, further comprising an ink, wherein the ink contains a coloring material, a water-soluble organic solvent, a resin, and a surfactant. An image forming method comprising: a step of applying a processing liquid on a recording medium; and a step of applying ink to the recording medium to which the processing liquid has been applied,
The treatment liquid contains a polyvalent metal salt and has a dynamic surface tension (A) of 15 ms and a static surface tension (B) in a relationship of 59 ≧ A ≧ 50 mN / m, 27 ≦ B ≦ 38 mN / m, 2 .1 ≧ A / B ≧ 1.5, and the recording medium and the processing liquid have a relationship between the roughness index Vr obtained by the Bristow method and the liquid absorption Vi of 20 ms ^0.5 , which is 1.5 ≦ ( (Vi / Vr) ≦ 2.5. An image forming apparatus comprising: means for applying a processing liquid onto a recording medium; and means for applying ink to the recording medium to which the processing liquid has been applied,
The treatment liquid contains a polyvalent metal salt and has a dynamic surface tension (A) of 15 ms and a static surface tension (B) in a relationship of 59 ≧ A ≧ 50 mN / m, 27 ≦ B ≦ 38 mN / m, 2 .1 ≧ A / B ≧ 1.5, and the recording medium and the processing liquid have a relationship between the roughness index Vr obtained by the Bristow method and the liquid absorption Vi of 20 ms ^0.5 , which is 1.5 ≦ ( (Vi / Vr) ≦ 2.5.

Images