JP6866752B2 - Ink and treatment liquid set, recording method, recording device, and treatment liquid - Google Patents

Description

The present invention relates to a set of ink and a treatment liquid, a recording method, a recording device, and a treatment liquid.

In various types of printing, processing for reducing the glossiness of an image may be performed. For example, in matte printing or matte printing in offset printing, the glossiness of an image is reduced by including medium in the ink. In the inkjet recording method, the glossiness of an image can be reduced by using special paper. However, according to this method, the degree of freedom in selecting the recording medium is limited.

In Patent Document 1, a UV-curable transparent ink is applied and instantly cured to diffusely reflect the finished surface to increase the degree of frostiness (decrease the glossiness), and the degree of frostiness or glossiness of the transparent coating layer. It is described that an image forming layer having a matte tone (matte tone) or a glossy tone or an intermediate finished appearance thereof can be easily obtained by adjusting the above.

The use of water-based ink may be required in the inkjet recording method for reasons such as ease of handling. However, according to the method using the water-based ink, blocking occurs due to the other recording medium overlapping the image of the recording medium before drying, and the ejection stability deteriorates due to the drying of the treatment liquid. An object of the present invention is to provide a set of an ink and a treatment liquid which achieves a reduction in the glossiness of an image and is excellent in blocking property and ejection stability.

The invention according to claim 1 has the ink, and the treatment liquid on the recording medium in which the ink is applied, the ink is an organic solvent, and water seen including, the treatment liquid, an organic solvent, and water, In addition, it contains at least one of urethane resin particles and acrylic resin particles, and the dissolution parameter of the treatment liquid in the organic solvent and water is 1.5 (cal / cal /) with respect to the dissolution parameter of the ink in the organic solvent and water. cm ³ ) ^{A set of ink and treatment liquid that is 1/2} or more high and has an acid group amount of at least one of the urethane resin particles and the acrylic resin particles in the treatment liquid of 0.3 meq / g or more.

According to the present invention, it is possible to provide a set of an ink and a treatment liquid which achieves a decrease in glossiness of an image and is excellent in blocking property and ejection stability.

It is a schematic diagram of the inkjet recording apparatus as an image forming apparatus which concerns on one Embodiment. It is the schematic of the image formation process part which concerns on one Embodiment. It is an enlarged view of a head unit. It is a titration curve which recorded the pH change with respect to the dropping amount of HCl for a polyurethane resin emulsion. It is the figure which differentiated the titration curve of FIG.

Hereinafter, embodiments of the present invention will be described. Hereinafter, the treatment liquid used on the surface of the recording medium to which the ink is applied is referred to as a post-treatment liquid. Further, a set having ink and a post-treatment liquid is referred to as an image forming set.

(Image formation set)
The image forming set of the present embodiment includes an ink and a post-treatment liquid (an example of a treatment liquid), and further contains other components as necessary.

<Ink>
The ink in the image forming set is a water-based ink, which comprises a first mixed solution (an example of a first solution), and optionally a colorant, and optionally other components.

<< First mixed solution >>
The first mixed solution contains an organic solvent and water. Further, the first mixed solution may contain those classified functionally as penetrants, antifoaming agents and the like. The solubility parameter (hereinafter referred to as "SP value") of the first mixed solution ^{is preferably 14 (cal / cm 3} ) ^1/2 or more and 20 (cal / cm ³ ) ^1/2 or less, and 15 ( cal / cm ³ ) ^1/2 or more and 17 (cal / cm ³ ) ^1/2 or less are more preferable. When the ink contains organic solvents A, B, ..., N, the SP value of the mixed solution of the organic solvent and water in the ink (first mixed solution) is calculated from the following formula (A). be able to.

^{SP value (cal / cm 3} ) ^1/2 of the mixed solution of organic solvent and water in the ink (first mixed solution)
= [SP value of organic solvent A x body integration rate of organic solvent A in mixed solution] + [SP value of organic solvent B x body integration rate of organic solvent B in mixed solution] + ... + [of organic solvent N SP value x body integration rate of organic solvent N in mixed solution] + [SP value of water x body integration rate of water in mixed solution] ... Equation (A)

The SP value is a numerical value of how easily each other melts. The SP value is represented by the attractive force between the molecules, that is, the square root of the cohesive energy density CED (Cohesive Energy Density). The CED is the amount of energy required to evaporate 1 mL of the substance.

The SP value can be calculated by the Fedors method using the following formula (B).
SP value (solubility parameter) = (CED value) ^1/2 = (E / V) ^1/2 ... Equation (B)

In formula (B), when E is the molecular aggregation energy (cal / mol) and V is the molecular volume (cm ³ / mol), the evaporation energy of each atomic group in the molecule is Δei, and the molar volume is Δvi. It is represented by the following formula (C) and formula (D). In addition, Σ in the following formula (C) and formula (D) represents the sum of Δei or Δvi of each atomic group in the molecule.
E = ΣΔei ・ ・ ・ ・ ・ Equation (C)
V = ΣΔvi ・ ・ ・ ・ ・ Equation (D)

There are various methods for calculating the SP value, but in this embodiment, the Fedors method is used. For the calculation of SP value and various data such as evaporation energy Δei and molar volume Δvi of each atomic group used in the calculation, refer to "Basic Theory of Adhesion" (written by Minoru Imoto, published by Polymer Publishing Association, Chapter 5). The described ones can be used. For data not shown in the above literature, such as ₃ -CFs, see R.M. F. Fedors, Polym. Eng. Sci. 14,147 (1974) can be referred to. For reference, when converting the SP value represented by the formula (B) to (J / cm ³ ) ^1/2 , 2.046 is converted to SI unit (J / m ³ ) ^1/2 . In that case, it may be multiplied by 2,046. In this embodiment, the organic solvent and water are taken into consideration in the above calculation of the SP value for those contained in an amount of 3% by mass or more with respect to the total amount of the ink.

<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 ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-Pentanediol, 1,5-Pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, 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 Polyhydric alcohol alkyl ethers such as ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone. , 1,3-Dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and other nitrogen-containing heterocyclic compounds, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N- Amidos such as dimethylpropionamide, 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. And so on.
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.

Polyol compounds having 8 or more carbon atoms and glycol ether compounds 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 glycol ether compounds 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 can be mentioned.

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.

<Water>
The water is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include pure water such as ion-exchanged water, ultra-filtered water, reverse osmosis water and distilled water; and ultrapure water. These may be used alone or in combination of two or more. The SP value of water is 23.4 (cal / cm ³ ) ^1/2 .

<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. Moreover, you may use a mixed crystal.
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, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, carbon black produced by known methods such as contact method, furnace method, and thermal method. 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, acidic 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 Carmin 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Magenta), 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 the 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 image density, good fixability and ejection stability. It is as follows.

In order to disperse the pigment to obtain an ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersing 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 coating pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effects of the present invention are not impaired. May be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low molecular weight dispersant and a 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.
RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and a naphthalene sulfonate Na formalin condensate can also be suitably used as a 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 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 preferable 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, 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. However, from the viewpoint of obtaining good ejection stability and increasing the image density, 0.1 mass is used. % Or more and 50% by mass or less are preferable, and 0.1% by mass or more and 30% by mass or less are more preferable.
If necessary, the pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifuge, or the like.

<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 dispersed 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 diameter 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 Microtrack 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 according to the purpose, but from the viewpoint of improving image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number of inks. Is preferably 20 nm or more and 1000 nm or less, 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 Microtrack Bell Co., Ltd.).

<Additives>
If necessary, a surfactant, a defoaming agent, an antiseptic / antifungal agent, a rust preventive, a pH adjuster, or 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 may be appropriately selected depending on the intended purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, side chain double-ended modified polydimethylsiloxane, and the like. Those having an oxyethylene group and a polyoxyethylene polyoxypropylene 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 a compound 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 compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property. 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. The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. The counterions of the salts in these fluorine-based surfactants are Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH). ₃ etc. can be mentioned.
Examples of the amphoteric tenside agent include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, and lauryldihydroxyethylbetaine.
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, and polyoxyethylene alkyl ether sulfate salt.
These may be used alone or in combination of two or more.

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. Examples thereof include polydimethylsiloxane modified at both ends of the chain, and a polyether-modified silicone-based surfactant having a polyoxyethylene group and a polyoxyethylene polyoxypropylene group as modifying groups exhibits good properties as an aqueous surfactant, and is particularly effective. preferable.
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, the 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.

一般式（Ｓ−１）
（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。）

General formula (S-1)
(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.

The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of excellent wettability and ejection stability and improvement in image quality, 0.001 mass is used. % Or more and 5% by mass or less are preferable, and 0.05% by mass or more and 5% by mass or less are more preferable.

<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.

<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.

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, 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, more preferably 8 to 11, from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

The above-mentioned ink raw material is an example, and the ink raw material in the present invention is not limited to the above. Raw materials and the like specifically shown in the examples are also preferably used in the present invention.

<Post-treatment liquid>
The post-treatment liquid in the image forming set is used to reduce the glossiness of the image. The post-treatment liquid contains a second mixed solution (an example of the second solution), and at least one of a urethane resin and an acrylic resin, and if necessary, a wax, a self-crosslinking resin, and other components. To do.

<< Second mixed solution >>
The second mixed solution in the post-treatment liquid contains an organic solvent and water. The SP value of the second mixed solution ^{is preferably 10 (cal / cm 3} ) ^1/2 or more and 30 (cal / cm ³ ) ^1/2 or less, and 19 (cal / cm ^{3 ) 1/2} or more and 22 (cal). / cm ³ ) ^1/2 or less is more preferable.

The solubility parameter (SP value) of the organic solvent and water mixed solution (second mixed solution) in the post-treatment liquid is based on the SP value of the organic solvent and water mixed solution (first mixed solution) in the ink. The difference is 1.5 (cal / cm ³ ) ^1/2 or more higher, 1.5 (cal / cm ³ ) ^1/2 or more and 5.0 (cal / cm ³ ) ^1/2 or less. Is preferable.

When the SP value of the second mixed solution in the post-treatment liquid is 1.5 (cal / cm ³ ) ^1/2 or more higher than the SP value of the first mixed solution in the ink, the post-treatment liquid is mixed. Even when it is applied to the surface of an unfixed image, it is possible to prevent the post-treatment solution from being mixed with the unfixed image. This reduces the glossiness of the image. Further, the glossiness of the image can be sufficiently reduced in the range where the above SP value is 5.0 (cal / cm ³ ) ^{1/2 or less.} The SP value of the organic solvent in the post-treatment liquid, the SP value of water, and the SP value of the organic solvent and the second mixed solution of water are the SP value of the organic solvent in the ink described above and the SP value of water. It can be calculated in the same manner as the SP value and the SP value in the first mixed solution of the organic solvent and water. In the present embodiment, only those containing 3% by mass or more of the organic solvent and water with respect to the total amount of the post-treatment liquid are considered in the calculation of the SP value.

<Organic solvent for post-treatment liquid>
The organic solvent used for the post-treatment liquid is not particularly limited, and the same organic solvent as that used for the ink can be used. Examples of the post-treatment liquid include those discharged from the recording head. Therefore, from the viewpoint of dischargeability from the recording head and maintainability, it is preferable to contain at least one of glycerin, diethylene glycol, diglycerin, and 1,3-butanediol as the organic solvent. These may be used alone or in combination of two or more.

<Water>
As the water used for the post-treatment liquid, the same water as that used for the ink can be used.

<Resin>
The post-treatment liquid contains a resin in order to reduce the glossiness of the image and improve the scratch resistance of the image. Examples of the resin include urethane resin and acrylic resin. These may be used alone or in combination of two or more.

When two or more kinds of resins are used in combination, it is preferable to use at least two kinds of urethane resin particles and acrylic resin particles having different volume average particle diameters. Specifically, at least one resin particle having a larger volume average particle diameter (D50) and a smaller volume average particle diameter (D50) than the volume average particle diameter (D50) of the coloring material used for the ink. It is preferably contained seed by seed. When resin particles having a volume average particle size smaller than the volume average particle size of the color material used for ink are used, the resin can penetrate into small gaps between the color materials, improving the scratch resistance of the image. be able to.

The amount of acid groups in the resin is preferably 0.3 meq / g or more and 5.0 meq / g or less. The acid group of the resin imparts hydrophilicity to the resin and affects the separability of the organic solvent and the resin particles in the post-treatment liquid after being applied to the recording medium. By setting the amount of acid groups in the resin to 0.3 meq / g or more and 5.0 meq / g or less, the glossiness of the formed image can be reduced. Further, when the acid group amount of the resin is 0.3 meq / g or more, the blocking property and the discharge stability can be improved. In the present embodiment, the amount of acid groups in the resin is measured according to the method described in JP-A-2007-3454. According to this method, 5 g of a sample is weighed in a 200 ml beaker and 25 ml of 0.2 N NaOH is added thereto. Ion-exchanged water is added to the above sample to make the total volume 50 ml. A stirrer is put in the above sample, set in a magnetic stirrer, and stirred. A pH meter electrode is set on the above sample, and 0.2N HCl is added dropwise while stirring with a stirrer. The amount of Dropped HCl and the amount of pH change are recorded, and the amount of acid group is calculated from the obtained first equivalent point and the amount of HCl required at the second equivalence point.

FIG. 4 is a titration curve recording the pH change of the polyurethane resin emulsion a and the polyurethane resin emulsion b with respect to the amount of hydrochloric acid added dropwise. FIG. 5 is a diagram obtained by differentiating the titration curve of FIG. FIG. 4 is a titration curve recording the pH change with respect to the amount of HCl added dropwise. The range p in FIG. 4 indicates the first equivalence point of the polyurethane resin emulsion a and the polyurethane resin emulsion b, and the range q indicates the second equivalence point. In the range shown in (1), NaOH is neutralized and (2). ), The −COOH group is neutralized. FIG. 5 is a diagram obtained by differentiating the titration curve of FIG. 4 in order to see the inflection point. The polyurethane resin emulsion a has a first equivalence point pa and a second equivalence point qa, and the polyurethane resin emulsion b has a first equivalence point pb and a second equivalence point qb. In FIG. 5, the amount of −COOH groups can be calculated from the amount of HCl required from the first equivalence point to the second equivalence point. At the time of calculation, the ratio of active ingredients in the resin is taken into consideration. The amount of acid groups in the polyurethane resin emulsion a obtained from FIG. 5 is 2.07 (meq / g), and the amount of acid groups in the polyurethane resin emulsion b is 0.30 (meq / g).

The lower limit of the glass transition point (Tg) of the resin is preferably 20 ° C. or higher, and the upper limit is preferably 100 ° C. or lower. When the glass transition point is 20 ° C. or higher, the bondability between the resin and the recording medium can be physically improved, the resin is less likely to come off, and the abrasion resistance can be improved. it can. As the glass point transfer increases, the scratch resistance improves, but if the temperature is 100 ° C. or lower, sufficient scratch resistance of the image can be obtained. The glass transition point can be measured by a differential scanning calorimetry (DSC) or TMA thermomechanical analysis (TMA).

The volume average particle diameter (D50) of the resin particles is preferably 10 nm or more and 200 nm or less. When the volume average particle diameter (D50) is 10 nm or more, the viscosity of the resin does not become too high, and the ejection stability at the recording head can be improved. When the volume average particle diameter (D50) is 200 nm or less, the image forming apparatus using the resin Nozzle clogging can be suppressed. The volume average particle size can be measured using a particle size distribution measuring device (trade name: Microtrack UPA, manufactured by Nikkiso Co., Ltd.) or the like.

As for the content of the resin, the lower limit value is preferably 10% by mass or more, more preferably 12% by mass or more, and the upper limit value is more preferably 50% by mass or less with respect to the total amount of the post-treatment liquid. .. When the content of the resin is less than 10% by mass, the effect of lowering the gloss is small and the gloss is hardly lowered. When the content of the resin is more than 50% by mass, the glossiness increases.

-Acrylic resin-
The acrylic resin is not particularly limited, but a commercially available product can be used. Commercially available acrylic resins KP-543, KP-545, KP-549 manufactured by Shin-Etsu Chemical Co., Ltd .; AQ-914, AQ-ASi-91, AQ-4790 manufactured by Daicel FineChem Co., Ltd., SIFCLEAR manufactured by JSR Corporation Series etc. can be mentioned. These may be used alone or in combination of two or more.

-Urethane resin-
The urethane resin is not particularly limited, but a commercially available product can be used. Examples of commercially available urethane resins include Permarin series and Ucoat series manufactured by Sanyo Chemical Industries, Ltd., W5661 and XW-75-W932 manufactured by Mitsui Chemicals Co., Ltd., and SF460S manufactured by NUC Co., Ltd. Further, a material obtained by grafting an aqueous urethane resin and an acrylic resin, such as WEM-3000 manufactured by Taisei Fine Chemical Co., Ltd., may be used. These may be used alone or in combination of two or more. Among the urethane resins, a polyether urethane resin is particularly preferable from the viewpoint of the degree of decrease in gloss when the post-treatment liquid is applied to the image forming portion.

<< Other ingredients >>
The other components are not particularly limited as long as they can be used in the post-treatment liquid, and examples thereof include surfactants; antifoaming agents; pH adjusters; antiseptic and antifungal agents; and rust preventives. Can be mentioned.

-Surfactant-
Surfactants are included to reduce the surface tension of the post-treatment liquid. By containing a surfactant, the post-treatment liquid becomes moderately wet with the recording medium, the penetration speed into the recording medium can be increased, and defects such as scratch resistance and bleeding of the image can be improved. Can be done. As the surfactant, the same surfactant as that used for the water-based ink can be used.

-Foam suppressant; pH adjuster; antiseptic and fungicide; rust preventive-
As the antifoaming agent, pH adjuster; antiseptic / antifungal agent; rust preventive agent, the same ones used for ink can be used.

The raw material of the treatment liquid described above is an example, and the raw material of the treatment liquid in the present invention is not limited to the above. Raw materials and the like specifically shown in the examples are also preferably used in the present invention.

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

(Image forming method and image forming device)
The image forming method (an example of a recording method) in the present embodiment includes an image forming step (an example of an ink applying step) in which a stimulus is applied to ink and ejected to form an image on a recording medium, and an ink is ejected. It has a post-treatment step (an example of a treatment liquid application step) of applying a post-treatment liquid on the surface.

The image forming apparatus in the present embodiment includes an image forming means (an example of an ink applying means) for forming an image on a recording medium by applying a stimulus to the ink and ejecting the ink, and a post-treatment liquid on the surface on which the ink is ejected. (An example of a treatment liquid applying means) and a post-treatment means for applying the above.

<Image forming process and image forming means>
The stimulus used in the image forming step is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include heat (temperature), pressure, vibration, and light. These may be used alone or in combination of two or more. Among these, heat and pressure are preferably used.

As an aspect of ink ejection, for example, a piezoelectric element is used as a pressure generating means to deform a vibrating plate forming a wall surface of the ink flow path to change the internal volume of the ink flow path to eject ink droplets, so-called piezo. Method: A so-called thermal method in which ink is heated in an ink flow path using a heat generating resistor to generate bubbles. A vibrating plate and an electrode forming a wall surface of the ink flow path are arranged to face each other, and the vibrating plate and the electrode are arranged. Examples thereof include an electrostatic method in which the internal volume of the ink flow path is changed to eject ink droplets by deforming the vibrating plate by the electrostatic force generated between the two.

The size of the ink droplets to be ejected is preferably, for example, 3 pl or more and 40 pl or less. The ink ejection speed is preferably 5 m / s or more and 20 m / s or less. The drive frequency for ejecting ink is preferably 1 kHz or higher. The resolution formed by the ejected ink is preferably 300 dpi or more.

<Post-treatment means and post-treatment process>
As the post-treatment step, a method of applying the post-treatment liquid on the surface on which the ink is discharged may be used, and there is no particular limitation. As the post-treatment means, a applying means for applying the post-treatment liquid on the surface on which the ink is discharged may be used, and there is no particular limitation.

Examples of the applying method include an inkjet method, a blade coating method, a gravure coating method, a gravure offset coating method, a bar coating method, a roll coating method, a knife coating method, an air knife coating method, a comma coating method, a U comma coating method, and an AKKU coating. Examples thereof include a method, a smoothing coating method, a microgravure 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.

The post-processing step and the post-processing means may be performed on an image in which the image formed by the ink is sufficiently fixed on the recording medium, or may be performed on an image in which the image is not fixed. In either case, the glossiness of the image can be reduced. The amount of acid groups in the resin in the post-treatment liquid of the present embodiment is 0.3 meq / g or more and is hydrophilic. When the post-treatment liquid is applied to the recording medium, the resin in the post-treatment liquid is rapidly separated from the organic solvent and fixed. The post-treatment liquid of the present embodiment has excellent fixability and suppresses blocking even when applied to an unfixed image. The image forming apparatus of the present embodiment has a drying means (drying step) for drying ink in a transport path (transport step) between the image forming means (image forming step) and the post-processing means (post-processing step). ) Does not have to be provided. When the drying means is provided, examples of the drying means include a roll heater, a drum heater, and a means for drying the recording medium with warm air.

The drying temperature can be changed according to the type and amount of the water-soluble organic solvent contained in the ink and the minimum film forming temperature of the resin emulsion to be added, and further changed according to the type of the recording medium. Can be done.

The drying temperature is preferably higher than room temperature, more preferably 40 ° C. or higher and 120 ° C. or lower, and further preferably 50 ° C. or higher and 90 ° C. or lower, from the viewpoint of drying property and film formation temperature. When the heating temperature is 40 ° C. or higher and 120 ° C. or lower, it is possible to prevent damage caused by heat of the recording medium and prevent non-ejection due to warming of the ink head.

Wet adhesion amount to the recording medium of the post-treatment liquid in the post-treatment step is preferably from 0.1 g / m ² or more 30.0 g / m ² or less in the range, 0.2 g / m ² or more 10.0 g / More preferably m ² or less. When the wet adhesion amount is 0.1 g / m ² or more, the image quality (image density, saturation, color bleed, character bleeding, and white spot) can be improved, and is 30.0 g / m ² or less. As a result, it is possible to prevent the texture of plain paper from being impaired and to suppress the occurrence of curl.

Hereinafter, the image forming apparatus according to the embodiment will be specifically described with reference to FIGS. 1 to 3, but the present invention is not limited to the following description.

FIG. 1 is a schematic view of an inkjet recording device as an image forming device according to an embodiment. The inkjet recording device 300 includes a recording medium transport unit 301, a pretreatment process unit 302 that applies a pretreatment liquid to the recording medium 203, a pretreatment post-drying unit 303 that dries the recording medium 203 to which the pretreatment liquid is applied, and ink. An image forming process unit 304 provided with an accommodating portion, a post-treatment process unit 305 that applies a post-treatment liquid to the recording medium after the image forming step, and a post-treatment post-drying unit 306 that dries the recording medium 203 to which the post-treatment liquid is applied. It is composed of.

The recording medium transport unit 301 includes a paper feed device 307, a plurality of transport rollers, and a take-up device 308. The recording medium 203 is continuous paper (roll paper) wound in a roll shape, and the recording medium 203 is unwound from the paper feeding device by a transport roller, transported on a platen, and wound by a winding device.

FIG. 2 is a schematic view of an image forming process section according to an embodiment. The image forming process unit 304 is a full-line type head, and has four recording heads that can handle black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side in the recording medium transport direction. 304K, 304C, 304M, 304Y are arranged and configured. For example, the black (K) recording head 304K has four head units 305K that are short in the direction perpendicular to the transport direction as shown in FIG. 1,305K? 2,305K? 3,305K? The print area width is secured by arranging the 4s in a staggered pattern. FIG. 3 is an enlarged view of the head unit 304K-1. As shown in the figure, a large number of printing nozzles 310 are arranged along the longitudinal direction of the head unit 304K-1 on the nozzle surface 309 of the 304K-1 to form a nozzle row. In the present embodiment, the nozzle row is one row, but a plurality of rows may be provided. The other recording heads 304C, 304M, and 304Y have the same configuration, and the four recording heads 304K, 304C, 304M, and 304Y are arranged in the transport direction while maintaining the same pitch. As a result, it is possible to form an image over the entire width of the print area with one recording operation.

Since the head unit of the image forming process unit 304 and the head unit of the post-processing process unit 305 have the same configuration, the description thereof will be omitted. The head unit of the image forming process unit 304 and the head unit of the post-processing process unit 305 are adjacent to each other, and the post-treatment liquid is ejected to the surface of the ink between 0.5 seconds and 3 seconds after the ink is ejected. .. In carrying out the present invention, the pretreatment liquid, the pretreatment process unit 302, and the pretreatment process unit 302 may or may not be used.

Hereinafter, examples of the present invention and comparative examples will be described, but the present invention is not limited to these examples. In the table, the unit of the solubility parameter (SP value) is "(cal / cm ³ ) ^1/2 ", and the unit of the amount of each component in the ink and the post-treatment liquid is "mass%". In the table, the unit of acid group amount is "(meq / g)".

(Example 1)
<Ink>
<< Preparation example of styrene-acrylic copolymer containing anionic group >>
550 g of methyl ethyl ketone in the reaction vessel of an automatic polymerization reactor (polymerization tester DSL-2AS type, manufactured by Todoroki Sangyo Co., Ltd.) having 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. The inside of the reaction vessel was replaced with nitrogen while being charged and stirred. After heating the inside of the reaction vessel at 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 NOF CORPORATION) was added dropwise over 4 hours. After completion of the dropping, the reaction was continued at the same temperature for 15 hours, and the acid value was 100 (measured by the method described in JIS K 0070-1992), the weight average molecular weight was 21,000 (D5280 LCS M-PDA, stock). A methyl ethyl ketone solution of an anionic group-containing styrene-acrylic copolymer A at a glass transition point of 31 ° C. (STA7200, measured by Hitachi High-Tech Science Co., Ltd.) was obtained. After completion of the reaction, a part of methyl ethyl ketone was distilled off under reduced pressure to obtain an anionic group-containing styrene-acrylic copolymer A solution having a non-volatile content adjusted to 50%.

<< Preparation of aqueous pigment dispersion >>
800 g of carbon black (trade name: Raven 1080, manufactured by Colombian Carbon Japan Co., Ltd.) and 200 g of anionic group-containing styrene-acrylic copolymer A solution in a mixing tank equipped with a cooling jacket, and 10% sodium hydroxide. 143 g of an aqueous solution, 100 g of methyl ethyl ketone, and 1,957 g of water were charged and mixed by stirring. The mixed solution is passed through a disperser (trade name: SC Mill SC100, manufactured by Mitsui Mining Co., Ltd.) filled with zirconia beads having a diameter of 0.3 mm, and the circulation method (the method of returning the dispersant from the disperser to the mixing tank) Dispersed for 6 hours. The rotation speed of the disperser was set to 2,700 rpm, and cold water was passed through the cooling jacket so that the dispersion temperature was maintained at 40 ° C. or lower. After completion of the dispersion, 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 stock 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 Nuche type filtration device 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 (trade name: TK homodisper, manufactured by Primix Corporation), and add water to prepare a non-volatile component to make it non-volatile. An aqueous pigment dispersion dispersed in an aqueous medium as composite particles coated with a carboxyl group-containing styrene-acrylic copolymer in which 20% of carbon black was neutralized in potassium hydroxide was obtained.

<< Preparation example of ink 1 >>
Rosin-modified maleic acid resin (carboxyl group-containing resin) 2.0 g, glycerin (water-soluble organic solvent, SP value: 16.4 (cal / cm ³ ) ^1/2 ) 2.5 g, 3-methoxy-1-butanol ( Water-soluble organic solvent, SP value: 10.0) (cal / cm ³ ) ^1/2 ) 35.0 g, tripropylene glycol methyl ether (water-soluble organic solvent, SP value: 9.8 (cal / cm ³ ) ^{1) / 2} ) 10.6 g, compound represented by formula (i) (fluorine-based surfactant) 0.4 g, 2-amino-2-ethyl-1,3-propanediol (pH adjuster) 0.2 g, benzo 0.1 g of triazole (antiseptic and anti-rust agent) and ^{40.0 g of water (SP value: 23.4 (cal / cm 3} ) ^1/2 ) were stirred for 1 hour and mixed uniformly. Next, 1.2 g of N-octyl-2-pyrrolidone (foaming agent) was added, and the mixture was further stirred for 1 hour and mixed uniformly. Then, 8.0 g of the aqueous pigment dispersion in terms of solid content was added, and 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 to remove coarse particles and dust to obtain Ink 1. Table 1 shows the composition and content of the ink 1 and the SP value of the mixed solution (first mixed solution) in the ink calculated by the method described in the embodiment.

The volume average particle size (D50) of the pigment dispersion used in the examples was 0.01 mass by using Microtrack UPA-150 manufactured by Nikkiso Co., Ltd. and the solid content concentration (mass concentration) in the measurement sample was 0.01 mass. As a result of measurement using a sample diluted with pure water so as to be%, it was 120 nm.

<Post-treatment liquid>
-Preparation of post-treatment liquid 1-
Water-soluble organic solvent B: Glycerin (SP value: 16.4 (cal / cm ³ ) ^1/2 ) 20.0 g, Water-soluble organic solvent C: 1,3 butanediol (SP value: 12.8 (cal / cm)) ³ ) ^1/2 ) 10.0 g, urethane resin a: Product name: Superflex SF-210 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 37.5 g, Polyurethane wax emulsion A (Product name: Nopcoat MS-40, Sannopco) Co., Ltd.) 5.0 g, 0.4 g of surfactant represented by the above formula (i), 1.2 g of N-octyl-2-pyrrolidone, 2.0 g of octanediol, 2-amino-2-ethyl-1 , 3-Propanediol 0.2 g, benzotriazole 0.1 g, and ion-exchanged water (SP value: 23.4 (cal / cm ³ ) ^1/2 ) 23.6 g were stirred for 1 hour and mixed uniformly. The post-treatment liquid 1 used in Example 1 was obtained.

(Examples 2 to 15 and Comparative Examples 1 to 6)
A post-treatment liquid was prepared in the same manner as in Example 1 except that the composition of the post-treatment liquid was changed to that shown in the columns of Examples 2 to 15 of Tables 2 to 5 or Comparative Examples 1 to 6. .. The ink used in Examples 2 to 15 and Comparative Examples 1 to 6 is the same ink 1 as in Example 1. Tables 2 to 5 show the SP values of the mixed solutions (second mixed solutions) in the post-treatment liquids of Examples 1 to 15 and Comparative Examples 1 to 6 and the amount of resin acid groups. The SP value is calculated by the method described in the embodiment. The amount of resin acid group in Example 13 is calculated by the following formula.
(Polyester urethane resin a acid group amount 0.74 (meq / g) x 20 (mass%) + acrylic resin A acid group amount 0.4 (meq / g) x 17.5 (mass%)) / (20 (mass%) + 17.5 (mass%)) = 0.58

Details of the compounds in Tables 2 to 4 are shown below.
* Water-soluble organic solvent A: 3-methoxy-1-butanol (SP value: 10.0 (cal / cm ³ ) ^1/2 , manufactured by Tokyo Chemical Industry Co., Ltd.)
* Water-soluble organic solvent B: Glycerin (SP value: 16.4 (cal / cm ³ ) ^1/2 , manufactured by Wako Pure Chemical Industries, Ltd.)
* Water-soluble organic solvent C: 1,3 butanediol (SP value: 12.8 (cal / cm ³ ) ^1/2 , manufactured by Sankyo Chemical Co., Ltd.)
* Polyester urethane resin a: Product name: Superflex SF-210 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
* Polyester urethane resin b: Product name: NeoRezR-600 (manufactured by Kusumoto Kasei Co., Ltd.)
* Urethane acrylic resin c: Product name: NeoPacR9699 (manufactured by Kusumoto Kasei Co., Ltd.)
* Polyester urethane resin d: Product name: Permarin UA00 (manufactured by Sanyo Chemical Industries, Ltd.)
* Polyester urethane resin e: Product name: SU-100N (manufactured by Chuo Rika Kogyo Co., Ltd.)
* Polyester urethane resin f: Product name: NeoRezR-2170 (manufactured by Kusumoto Kasei Co., Ltd.)
* Acrylic resin A: Product name: NeoCylA1094 (Kusumoto Kasei Co., Ltd.)
* Acrylic resin B: Product name: NeoCylA662 (Kusumoto Kasei Co., Ltd.)
* Acrylic resin C: Product name: Mobilel LDM6740 (manufactured by Nippon Synthetic Chemistry Co., Ltd.)
* Acrylic resin D: Product name: Movinyl 972 (manufactured by Nippon Synthetic Chemistry)
* Acrylic resin E: Product name: TOCRYLW4322 (manufactured by Toyochem)
* Polyethylene wax emulsion A: Product name: Nopco Maru MS-40 (manufactured by San Nopco Ltd., melting point: 79 ° C)
* Polyethylene wax emulsion B: Product name: Nopcoat PEM-17 (manufactured by San Nopco Ltd., melting point: 105 ° C)
* Isocyanate group-containing resin: Product name: Elastron E-37 (Daiichi Kogyo Seiyaku Co., Ltd.)
* A compound represented by the following formula (i), which is a fluorine-based surfactant (trade name: Unidyne DSN-403N), manufactured by Daikin Industries, Ltd.)

<Image formation method>
The inks shown in Table 1 are ejected onto a recording medium (trade name: Mirror Coat Gold, manufactured by Oji Paper Co., Ltd .: glossiness of paper 60) by an image forming apparatus (trade name: IPSIO GXe5500, manufactured by Ricoh Co., Ltd.) and dots. An unfixed solid image of 3 cm square formed by a pattern is formed, and after 1.5 seconds, on the surface of the solid image, after Examples 1 to 15 or Comparative Examples 1 to 6 shown in Tables 2 to 5. The processing liquid was discharged by the image forming apparatus. Then, it was dried at 90 ° C. for 2 minutes with warm air and a drum heater to obtain a fixed image. In Example 11, before applying the post-treatment liquid, the post-treatment liquid of Example 11 is applied to the surface of the solid image after drying with warm air and a drum heater at 90 ° C. for 2 minutes. Was discharged by. Various characteristics of the obtained image were evaluated by the following methods. The evaluation results are shown in Tables 2-5.

<< Image glossiness >>
The image glossiness (60 ° gloss) of a solid portion of a 3 cm square solid image formed by the above method was measured with a gloss meter (micro-TRI-gloss manufactured by BYK Gardener). The lower the value of the image glossiness, the better the matte printing and the matte printing. Note that those with a glossiness of 45 or less can be used as those with a practically low glossiness, and those with a glossiness of 40 or less are more preferable. ..

<< Image scratch resistance >>
The solid part of the solid image of 3 cm square in the image formed by the above method is rubbed with a cloth attached to a friction tester (trade name: clock meter, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and then rubbed onto the cloth after rubbing. The transfer density of the ink was measured with a spectrophotometric densitometer (trade name: X-Rite939, manufactured by X-Rite). The smaller the transfer density, the better the scratch resistance of the image. If the transfer concentration is less than 0.20, it can be used without any problem in practical use.

<< Discharge stability >>
After printing the solid part of a solid image of 3 cm square by the above method, leave it for 1 hour without capping the recording head, then record the same image again, measure the number of non-ejection nozzles, and measure the following. "Discharge stability" was evaluated based on the evaluation criteria. If the following evaluation criteria are "○", it can be used without any problem in practical use.

-Evaluation criteria-
◯: No non-discharge ×: Non-discharge

<Blocking resistance>
A recording medium that has not been recorded is placed on the recording surface of the solid part of the solid image of 3 cm square recorded by the above method, sandwiched between two glass plates of 10 × 10 cm square, and a load of 1 kg is placed on the recording medium. It was left at 40 ° C. and 90% RH for 24 hours under the condition of / m ^2. After that, it was left at room temperature (25 ° C.) for 2 hours, and the degree of sticking between the recording media when peeled off was visually observed and evaluated according to the following evaluation criteria. If the following evaluation criteria are "○" or higher, it can be used without any problem in practical use.

-Evaluation criteria-
◯: No blocking (slightly sticky. There are slight scratches on the surface of the sample.)
×: With blocking (adjacent surface is closely fused. It is difficult to peel off.)

Japanese Unexamined Patent Publication No. 2008-21351

203 Recording medium 300 Inkjet recording device 301 Recording medium transport unit 302 Pretreatment process unit 303 Pretreatment and post-drying unit 304 Image formation process unit 304K, 304C, 304M, 304Y Recording head 305 Post-processing process unit 305K-1, 305K-2, 305K-3, 305K-4 Head unit 306 Post-processing drying section 307 Paper feed device 308 Winding device 309 Nozzle surface 310 Printing nozzle

Claims (10)

It has an ink and a processing liquid for a recording medium to which the ink is applied.
The ink contains an organic solvent and water, and contains
The treatment liquid contains at least one of an organic solvent, water, urethane resin particles, and acrylic resin particles.
The solubility parameter of the treatment liquid in the organic solvent and water is 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter of the ink in the organic solvent and water.
A set of an ink and a treatment liquid in which the amount of an acid group of at least one of the urethane resin particles and the acrylic resin particles in the treatment liquid is 0.3 meq / g or more. The ink according to claim 1, wherein the content of at least one of the urethane resin particles and the acrylic resin particles in the treatment liquid is 10% by mass or more and 50% by mass or less with respect to the total amount of the treatment liquid. Set of treatment liquid. The set of ink and treatment liquid according to claim 1 or 2, wherein the glass transition point of at least one of the urethane resin particles and the acrylic resin particles in the treatment liquid is 20 ° C. or higher and 100 ° C. or lower. The set of ink and treatment liquid according to any one of claims 1 to 3, wherein the resin particles in the treatment liquid are urethane resin particles. The set of ink and treatment liquid according to claim 4, wherein the urethane resin particles are polyether urethane resin particles. An ink application step of applying an ink containing an organic solvent and water to a recording medium, and
It has a treatment liquid application step of applying a treatment liquid containing at least one of an organic solvent, water, urethane resin particles, and acrylic resin particles to the ink-applied surface of the recording medium.
The solubility parameter of the treatment liquid in the organic solvent and water is 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter of the ink in the organic solvent and water.
A recording method in which the amount of at least one of the urethane resin particles and the acrylic resin particles in the treatment liquid is 0.3 meq / g or more. The recording method according to claim 6, wherein the drying step of drying the ink is not provided between the ink applying step and the processing liquid applying step. An ink storage unit that stores ink containing organic solvent and water,
An ink applying means for applying the ink to a recording medium,
Organic solvent, and water, and urethane resin particles, and accommodates the processing liquid containing at least one of acrylic resin particles, the treatment liquid application for imparting the treatment liquid surface on which the ink is applied in the recording medium With means,
The solubility parameter of the treatment liquid in the organic solvent and water is 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter of the ink in the organic solvent and water.
A recording device in which the amount of at least one of the urethane resin particles and the acrylic resin particles in the treatment liquid is 0.3 meq / g or more. The recording device according to claim 8, further comprising no drying means for drying the ink in the transport path of the recording medium between the ink applying means and the processing liquid applying means. It is applied to a recording medium to which an organic solvent and an ink containing water are applied.
Containing at least one of organic solvent, water, urethane resin particles, and acrylic resin particles,
The solubility parameter of the treatment liquid in the organic solvent and water is 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter of the ink in the organic solvent and water.
A treatment liquid in which at least one of the urethane resin particles and the acrylic resin particles has an acid group amount of 0.3 meq / g or more.

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