JP2018111791A - Ink and treatment solution set, recording method, recorder and treatment solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that according to a method using water-based ink, blocking occurs by overlapping the other recording media on the image of a recording medium before drying, and discharge stability reduces by drying a treatment solution.SOLUTION: The ink includes an organic solvent and a first solution including water, and the treatment solution includes an organic solvent, a second solution including water and at least one of urethane resin particles and acrylic resin particles. A solubility parameter in the second solution of the treatment solution is higher by 1.5(cal/cm)or more to that in the first solution of the ink, and an acid group amount in at least one of the urethane resin particles and acrylic resin particles in the treatment solution is 0.3 meq/g or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a set of ink and processing liquid, a recording method, a recording apparatus, and a processing 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 the image is lowered 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 a recording medium is limited.

  In Patent Document 1, UV curable transparent ink is applied and cured instantaneously to diffusely reflect the finished surface to increase the haze (decrease glossiness), and the haze or glossiness of the transparent coating layer. It is described that it is possible to easily obtain an image forming layer having a matte tone (matte tone) or a glossy tone, or an intermediate finish appearance between them by adjusting the above.

  For reasons such as ease of handling, use of water-based ink may be required in the ink jet recording system. However, according to the method using water-based ink, blocking occurs due to the other recording medium overlapping on the image of the recording medium before drying, or the ejection stability decreases due to drying of the processing liquid. An object of the present invention is to provide a set of an ink and a treatment liquid that achieves a reduction in the glossiness of an image and is excellent in blocking properties and ejection stability.

The invention according to claim 1 includes an ink and a treatment liquid for the recording medium to which the ink is applied, the ink containing a first solution containing an organic solvent and water, and the treatment liquid includes: A second solution containing an organic solvent and water, and at least one of urethane resin particles and acrylic resin particles, and a solubility parameter of the treatment liquid in the second solution is the first solution of the ink 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter in the solution, and the acid group amount of at least one of the urethane resin particles and the acrylic resin particles in the treatment liquid is 0.3 meq. A set of ink and treatment liquid that is greater than / g.

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

1 is a schematic diagram of an ink jet recording apparatus as an image forming apparatus according to an 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 pH change with respect to the dripping amount of HCl about 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 processing liquid used on the surface of the recording medium to which ink is applied is referred to as post-processing liquid. A set having ink and post-treatment liquid is referred to as an image forming set.

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

<Ink>
The ink in the image forming set is a water-based ink, and includes a first mixed solution (an example of the first solution), and optionally a coloring material, and further includes other components as necessary.

<< first mixed solution >>
The first mixed solution contains an organic solvent and water. Further, the first mixed solution may include those classified as functional penetrants and foam suppressors. The dissolution parameter (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 is more preferable. When the organic solvent A, B,..., N is contained in the ink, the SP value of the mixed solution (first mixed solution) of the organic solvent and water in the ink is calculated from the following formula (A). be able to.

SP value (cal / cm ³ ) ^1/2 of mixed solution of organic solvent and water in ink (first mixed solution)
= [SP value of organic solvent A x volume fraction of organic solvent A in mixed solution] + [SP value of organic solvent B x volume fraction of organic solvent B in mixed solution] + ... + [of organic solvent N SP value × volume fraction of organic solvent N in mixed solution] + [SP value of water × volume fraction of water in mixed solution] Formula (A)

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

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

In the formula (B), E is the molecular cohesive energy (cal / mol), 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 shown by the following formula (C) and formula (D). In the following formulas (C) and (D), Σ represents the sum of Δei or Δvi of each atomic group in the molecule.
E = ΣΔei Expression (C)
V = ΣΔvi Equation (D)

Although there are various methods for calculating the SP value, the Fedors method is used in this embodiment. 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, see “Basic Theory of Adhesion” (Akira Imoto, published by Kobunshi Shuppankai, Chapter 5). Those described can be used. For data not shown in the above documents such as -CF ₃ group, R.C. F. Fedors, Polym. Eng. Sci. 14, 147 (1974). For reference, when converting the SP value represented by the formula (B) into (J / cm ³ ) ^1/2 , 2.046 is converted into SI units (J / m ³ ) ^1/2 . In that case, it may be multiplied by 2,046. In the present embodiment, the organic solvent and water are included in the calculation of the above SP value for those containing 3% by mass or more with respect to the total amount of 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, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, 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- -N-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, Examples thereof include ethylene carbonate.
In addition to functioning as a wetting agent, it is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because good drying properties can be obtained.

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 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. Examples of ethers include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

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

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of the drying property and ejection reliability of the ink, 20 mass% or more and 60 mass% or less are more preferable.

<Water>
There is no restriction | limiting in particular as water, According to the objective, it can select suitably, For example, pure water, such as ion-exchange water, ultrafiltration water, reverse osmosis water, distilled water; Ultrapure water etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. The SP value of water is 23.4 (cal / cm ³ ) ^1/2 .

<Color material>
The color material is not particularly limited, and pigments and dyes can be used.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used alone or in combination of two or more. A mixed crystal may be used.
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 pigment such as gold or silver, a metallic pigment, or the like can be used.
Carbon black produced by known methods such as contact method, furnace method, thermal method in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow as inorganic pigments Can be used.
Organic pigments include azo pigments, polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments). Dye chelates (for example, basic dye type chelates, acidic dye type chelates), nitro pigments, nitroso pigments, aniline black, and the like can be used. Of these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of pigments include black for carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11). And metal pigments such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).
Further, for color use, 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, etc.
The dye is not particularly limited, and an acid dye, a direct dye, a reactive dye, and a basic dye can be used. One kind may be used alone, or two or more kinds 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, and 35 are mentioned.

  The content of the color 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 improvement in image density, good fixability and ejection stability. It is as follows.

In order to obtain an ink by dispersing a pigment, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing, a dispersing agent is used. Method, etc.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a method of making it dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to the pigment (for example, carbon) Is mentioned.
As a method for coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is included in microcapsules and dispersible in water can be mentioned. This can be paraphrased as a resin-coated pigment. In this case, it is not necessary that all pigments blended in the ink are coated with a resin, and within a range where the effects of the present invention are not impaired, uncoated pigments and partially coated pigments are dispersed in the ink. It may be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular type dispersant or 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 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and naphthalenesulfonic acid Na formalin condensate can also be suitably used as a dispersant.
A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
An ink can be obtained by mixing a material such as water or an organic solvent with a pigment. Further, it is also possible to produce an ink by mixing a pigment, other water, a dispersant, and the like into a pigment dispersion and mixing a material such as water or an organic solvent.
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. For dispersion, a disperser is preferably used.
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 maximum number because the pigment dispersion stability 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 (Nanotrack Wave-UT151, manufactured by Microtrack 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% by mass. % To 50% by mass is preferable, and 0.1% to 30% by mass is more preferable.
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 resin contained in the ink is not particularly limited and can be appropriately selected according to the purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene type 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. An ink can be obtained by mixing resin particles with a material such as a colorant or an organic solvent in a resin emulsion state in which water is dispersed as a dispersion medium. As said resin particle, what was synthesize | combined suitably may be used and a commercial item may be used. Moreover, these may be used individually by 1 type, or may be used in combination of 2 or more types of resin particles.

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

  The resin content is not particularly limited and may be appropriately selected according to the purpose. However, from the viewpoint of fixability and ink storage stability, the content of the resin is 1% by mass or more and 30% by mass or less. Is preferable, and 5 mass% or more and 20 mass% or less are 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. From the viewpoint of improving the image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number Is preferably 20 nm to 1000 nm, and more preferably 20 nm to 150 nm. 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, 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 silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants and anionic surfactants can be used.
There is no restriction | limiting in particular in silicone type surfactant, According to the objective, it can select suitably. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, and side chain both terminal modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as an aqueous surfactant. In addition, as the silicone surfactant, a polyether-modified silicone surfactant can be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.
Examples of the fluorosurfactant 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. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylate. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. As counter ions of salts in these fluorosurfactants, 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. are mentioned.
Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, 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, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.
These may be used alone or in combination of two or more.

The silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side Since both ends of the chain are modified with polydimethylsiloxane, a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibits good properties as an aqueous surfactant. preferable.
As such a surfactant, an appropriately synthesized product 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., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.
The polyether-modified silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyalkylene oxide structure represented by the general formula (S-1) is represented by dimethylpolysiloxane. Examples thereof include those introduced into the side chain of Si part 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。）

Formula (S-1)
(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.)

  A commercial item can be used as said polyether modified silicone type surfactant, For example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Japan 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 (Bic Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

  There is no restriction | limiting in particular as content of surfactant in an ink, Although it can select suitably according to the objective, From the point which is excellent in wettability and discharge stability, and image quality improves, it is 0.001 mass. % To 5% by mass is preferable, and 0.05% to 5% by mass is more preferable.

<Antifoaming agent>
There is no restriction | limiting in particular as an antifoamer, For example, a silicone type antifoamer, a polyether type | system | group antifoamer, a fatty-acid ester type | system | group antifoamer etc. are mentioned. These may be used alone or in combination of two or more. Among these, a silicone type antifoaming agent is preferable from the viewpoint of excellent foam breaking effect.

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

<Rust preventive>
There is no restriction | limiting in particular as a rust preventive agent, For example, acidic sulfite, sodium thiosulfate, etc. are mentioned.

<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.

There is no restriction | limiting in particular as a physical property of an ink, According to the objective, it can select suitably, For example, it is preferable that a viscosity, surface tension, pH, etc. are the following ranges.
The viscosity at 25 ° C. of the ink 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 printing density and character quality and obtaining good discharge properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. Measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid amount 1.2 mL, rotation speed 50 rpm, and measurement is possible for 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less and more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is suitably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12 and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

  The above-described ink raw materials are examples, and the ink raw materials in the present invention are not limited to the above. The raw materials specifically shown in the examples are also preferably used in the present invention.

<Post-treatment liquid>
The post-processing 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), 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 mixed solution (second mixed solution) of the organic solvent and water in the post-treatment liquid is based on the SP value of the mixed solution (first mixed solution) of the organic solvent and water 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 It is preferable.

When the SP value in the second mixed solution in the post-treatment liquid is higher than the SP value in the first mixed solution in the ink by 1.5 (cal / cm ³ ) ^1/2 or more, the post-treatment liquid is Even when applied to the surface of an unfixed image, it is possible to prevent the post-processing liquid from being mixed into the unfixed image. This reduces the glossiness of the image. In addition, the glossiness of the image can be sufficiently lowered in the range where the SP value is 5.0 (cal / cm ³ ) ^1/2 or less. The SP value in the organic solvent in the post-treatment liquid, the SP value in water, and the SP value in the second mixed solution of the organic solvent and water are the SP value in the organic solvent in the ink described above, and in water. The SP value and the SP value in the first mixed solution of the organic solvent and water can be calculated. In the present embodiment, only the organic solvent and water that are contained in an amount of 3% by mass or more 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 used for the ink can be used. As the post-treatment liquid, for example, a liquid ejected from a recording head can be cited. For this reason, it is preferable that at least any one of glycerin, diethylene glycol, diglycerin, and 1,3-butanediol is contained as the organic solvent from the viewpoint of dischargeability from the recording head and maintainability. These may be used individually by 1 type and may use 2 or more types together.

<Water>
As the water used for the post-treatment liquid, the same water as 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 a urethane resin and an acrylic resin. These may be used individually by 1 type and may use 2 or more types together.

  When using 2 or more types of resin together, it is preferable to use at least 2 types of urethane resin particles and acrylic resin particles having different volume average particle diameters. Specifically, at least one resin particle having a volume average particle diameter (D50) larger than the volume average particle diameter (D50) of the color material used in the ink and at least one resin particle having a smaller volume average particle diameter (D50) are used. It is preferable to contain each species. When resin particles having a volume average particle diameter smaller than the volume average particle diameter of the color material used in the ink are used, the resin can enter even a small gap between the color materials, thereby 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 between the organic solvent and the resin particles in the post-treatment liquid after application to the recording medium. By setting the acid group amount of the resin to 0.3 meq / g or more and 5.0 meq / g or less, the glossiness of the formed image can be lowered. Furthermore, when the acid group amount of the resin is 0.3 meq / g or more, blocking property and ejection stability can be improved. In the present embodiment, the acid group amount of 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 into a 200 ml beaker, and 25 ml of 0.2N NaOH is added thereto. Add ion exchange water to the sample to make the total volume 50 ml. A stir bar is placed in the sample and set in a magnetic stirrer and stirred. A pH meter electrode is set on the sample, and 0.2N HCl is dropped while stirring with a stirrer. The amount of HCl dropped and the amount of pH change are recorded, and the amount of acid groups is calculated from the amount of HCl required for the obtained first equivalent point and second equivalent point.

  FIG. 4 is a titration curve in which changes in pH with respect to the amount of HCl dropped are recorded for polyurethane resin emulsion a and polyurethane resin emulsion b. FIG. 5 is a diagram obtained by differentiating the titration curve of FIG. FIG. 4 is a titration curve in which the change in pH with respect to the drop amount of HCl is recorded. The range p in FIG. 4 indicates the first equivalent point of the polyurethane resin emulsion a and the polyurethane resin emulsion b, the range q indicates the second equivalent point, and NaOH is neutralized in the range indicated by (1), (2 ) -COOH group is neutralized in the range indicated by. 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 equivalent point pa and a second equivalent point qa, and the polyurethane resin emulsion b has a first equivalent point pb and a second equivalent point qb. In FIG. 5, the amount of —COOH groups can be calculated from the amount of HCl required from the first equivalent point to the second equivalent point. At the time of calculation, the calculation is performed taking into account the active ingredient ratio in the resin. The acid group amount of the polyurethane resin emulsion a obtained from FIG. 5 is 2.07 (meq / g), and the acid group amount of 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 binding property between the resin and the recording medium can be physically improved, and it is difficult for the resin to be removed and the abrasion resistance can be improved. it can. As the glass point transfer is increased, the scratch resistance is improved. However, if it is 100 ° C. or lower, sufficient image scratch resistance can be obtained. The glass transition point can be measured by a differential scanning calorimeter (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. Nozzle clogging can be suppressed. The volume average particle diameter can be measured using a particle size distribution measuring device (trade name: Microtrac UPA, manufactured by Nikkiso Co., Ltd.).

  As the resin content, the lower limit is preferably 10% by mass or more, more preferably 12% by mass or more, and the upper limit 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 reducing the gloss is small and the gloss is hardly lowered. When the resin content is more than 50% by mass, the glossiness increases.

-Acrylic resin-
Although it does not specifically limit as an acrylic resin, A commercial item can be used. As commercial products of acrylic resin, 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. These may be used individually by 1 type and may use 2 or more types together.

-Urethane resin-
Although it does not specifically limit as a urethane resin, A commercial item can be used. Examples of commercially available urethane resins include permarine series, U-coat series manufactured by Sanyo Chemical Industries, Ltd., W5661, XW-75-W932, manufactured by Mitsui Chemicals, SF460S manufactured by NUC, and the like. Moreover, you may use what grafted water-based urethane resin and acrylic resin like WEM-3000 by Taisei Fine Chemical Co., Ltd. These may be used individually by 1 type and may use 2 or more types together. Among the urethane resins, polyether urethane resins are preferable from the viewpoint of gloss reduction when the post-treatment liquid is applied to the image forming portion.

<< Other ingredients >>
The other components are not particularly limited and may be any components that can be used in the post-treatment liquid. Examples thereof include surfactants; antifoaming agents; pH adjusting agents; antiseptic / antifungal agents; Can be mentioned.

-Surfactant-
The surfactant is contained in order to lower the surface tension of the post-treatment liquid. By containing a surfactant, the post-treatment liquid is moderately easily wetted with respect to the recording medium, can increase the penetration speed into the recording medium, and improve problems such as image scratch resistance and bleeding. Can do. As the surfactant, the same surfactants as those used for water-based inks can be used.

-Antifoaming agent; pH adjusting agent; Antiseptic / antifungal agent;
As the antifoaming agent, the pH adjusting agent, the antiseptic / antifungal agent, and the anticorrosive agent, the same ones used for ink can be used.

  In addition, the raw material of said process liquid is an example, Comprising: The raw material of the process liquid in this invention is not limited above. The raw materials 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, OHP sheet, and general-purpose printing paper.

(Image forming method and image forming apparatus)
An image forming method (an example of a recording method) in the present embodiment includes an image forming step (an example of an ink application step) in which an image is formed on a recording medium by applying a stimulus to the ink and ejecting the ink. And a post-treatment process (an example of a treatment liquid application process) for applying a post-treatment liquid on the surface.

  The image forming apparatus according to the present exemplary embodiment includes an image forming unit (an example of an ink applying unit) that discharges ink by applying a stimulus to the ink, and a post-processing liquid on the surface on which the ink is discharged. And post-processing means for applying (an example of processing liquid applying means).

<Image forming step and image forming means>
There is no restriction | limiting in particular as irritation | stimulation used by an image formation process, According to the objective, it can select suitably, For example, heat | fever (temperature), a pressure, a vibration, light, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferably used.

  As an ink discharge mode, for example, a piezoelectric element is used as a pressure generating unit, and a diaphragm that forms the wall surface of the ink flow path is deformed to change the volume of the ink flow path to discharge ink droplets. Method: A so-called thermal method in which bubbles are generated by heating ink in an ink flow path using a heating resistor; a vibration plate and an electrode that form a wall surface of the ink flow channel are arranged to face each other, and the vibration plate and the electrode For example, an electrostatic method in which an ink droplet is ejected by changing the volume in the ink flow path by deforming the vibration plate by an electrostatic force generated between the two and the like.

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

<Post-processing means and post-processing steps>
As the post-treatment process, there is no particular limitation as long as an application method for applying the post-treatment liquid onto the surface on which the ink has been ejected is used. As the post-processing means, there is no particular limitation as long as the applying means for applying the post-processing liquid onto the surface on which the ink is ejected is used.

  Examples of the application method include inkjet method, blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, and AKKU coating. Method, smoothing coating method, micro gravure coating method, reverse roll coating method, 4 to 5 roll coating method, dip coating method, curtain coating method, slide coating method, die coating method and the like.

  The post-processing step and the post-processing means may be performed on an image in which an image formed with ink is sufficiently fixed on a recording medium, or may be performed on an unfixed image. In either case, the glossiness of the image can be reduced. The acid group amount of the resin in the post-treatment liquid of this embodiment is 0.3 meq / g or more and has hydrophilicity. When the post-treatment liquid is applied to the recording medium, the resin in the post-treatment liquid is quickly separated from the organic solvent and fixed. The post-treatment liquid of this embodiment is excellent in fixability and suppresses blocking even when applied to an unfixed image. The image forming apparatus according to the present exemplary embodiment includes a drying unit (drying step) for drying ink on a conveyance path (conveying step) between the image forming unit (image forming step) and the post-processing unit (post-processing step). ) May not be provided. In the case where a drying unit is provided, examples of the drying unit include a roll heater, a drum heater, or a unit that dries the recording medium with hot 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 can also be changed according to the type of the recording medium. Can do.

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

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 / m ² or less is more preferable. 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 it is 30.0 g / m ² or less. Thus, the texture of plain paper can be prevented from being damaged, and curling can be suppressed.

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

  FIG. 1 is a schematic diagram of an ink jet recording apparatus as an image forming apparatus according to an embodiment. The ink jet recording apparatus 300 includes a recording medium transport unit 301, a pretreatment step 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 section 304 having a storage section, a post-processing process section 305 that applies a post-processing liquid to a recording medium after the image forming process, and a post-processing post-drying section 306 that dries the recording medium 203 applied with the post-processing liquid. It consists of

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

  FIG. 2 is a schematic diagram of an image forming process unit according to an embodiment. The image forming process unit 304 is a full-line head, and four recording heads that can handle black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side in the recording medium conveyance direction. 304K, 304C, 304M, and 304Y are arranged. For example, the black (K) recording head 304K has four head units 305K that are short in the direction orthogonal to the conveying direction as shown in FIG. 1, 305K? 2, 305K? 3, 305K? The print area width is secured by arranging 4 in a zigzag pattern. FIG. 3 is an enlarged view of the head unit 304K-1. As shown in the drawing, a large number of print nozzles 310 are arranged on the nozzle surface 309 of 304K-1 along the longitudinal direction of the head unit 304K-1, thereby constituting a nozzle row. In this embodiment, the number of nozzle rows is one, but a plurality of rows can 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 a single 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, 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-processing liquid is ejected to the surface of the ink within 0.5 seconds to 3 seconds after ink ejection. . In the implementation of the present invention, the pretreatment liquid, the pretreatment process unit 302, and the pretreatment process unit 302 may or may not be used.

Hereinafter, although an example of the present invention and a comparative example are given and explained, 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 the amount of acid groups is “(meq / g)”.

Example 1
<Ink>
<< Preparation Example of Anionic Group-Containing Styrene-Acrylic Copolymer >>
550 g of methyl ethyl ketone is added to a reaction vessel of an automatic polymerization reaction device (polymerization tester DSL-2AS type, manufactured by Sakai Sangyo Co., Ltd.) having a reaction vessel equipped with a stirring device, a dropping device, a temperature sensor and a reflux device having a nitrogen introducing device at the top. While charging and stirring, the inside of the reaction vessel was purged with nitrogen. The reaction vessel was heated at 80 ° C. while maintaining a nitrogen atmosphere, and then 75.0 g of methacrylic acid-2-hydroxyethyl, 77.0 g of methacrylic acid, 80.0 g of styrene and 150 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 dropped over 4 hours. After completion of dropping, the reaction was further continued at the same temperature for 15 hours, acid value: 100 (measured by the method described in JIS K 0070-1992), weight average molecular weight: 21,000 (D5280 LCS M-PDA, stock) The measurement was performed by Shimadzu Corporation), and the glass transition point: 31 ° C. (STA 7200, measurement performed by Hitachi High-Tech Science Co., Ltd.). An anionic group-containing styrene-acrylic copolymer A methyl ethyl ketone solution 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 nonvolatile content adjusted to 50%.

<< Preparation of aqueous pigment dispersion >>
In a mixing tank equipped with a cooling jacket, 800 g of carbon black (trade name: Raven 1080, manufactured by Colombian Carbon Japan Co., Ltd.), 200 g of an anionic group-containing styrene-acrylic copolymer A solution, 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 with stirring. The mixture is passed through a dispersion apparatus (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 system (a system in which the dispersion liquid discharged from the dispersion apparatus is returned to the mixing tank). Dispersed for 6 hours. The number of revolutions of the dispersing device was 2,700 rpm, and the temperature of the dispersion liquid was kept at 40 ° C. or less through the cooling jacket through cold water. After completion of the dispersion, the dispersion stock solution was extracted from the mixing tank, and then the mixing tank and the dispersion apparatus flow path were washed with 10,000 g of water, and the diluted dispersion liquid was obtained together with the dispersion stock solution. The diluted dispersion was put into a glass distillation apparatus, and the whole 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 the solid content was filtered with a Nutsche filter and washed with water. Take the cake in a container, add 200 g of 20% aqueous potassium hydroxide solution, and then disperse in a dispa (trade name: TK Homo Disper, manufactured by Primix Co., Ltd.). An aqueous pigment dispersion in which 20% carbon black was dispersed in an aqueous medium as composite particles coated with a carboxyl group-containing styrene-acrylic copolymer 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 surfactant) 0.4 g, 2-amino-2-ethyl-1,3-propanediol (pH adjuster) 0.2 g, benzo Triazole (antiseptic and rust preventive agent) 0.1 g and water (SP value: 23.4 (cal / cm ³ ) ^1/2 ) 40.0 g were stirred for 1 hour and mixed uniformly. Next, 1.2 g of N-octyl-2-pyrrolidone (foam suppressor) was added, and the mixture was further stirred for 1 hour and mixed uniformly. Thereafter, 8.0 g in terms of solid content of the aqueous pigment dispersion was added, and the mixture was further stirred for 1 hour and mixed uniformly. This mixture was subjected to pressure filtration through a polyvinylidene fluoride membrane filter having an average pore diameter 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 diameter (D50) of the pigment dispersion used in the examples was measured using a Microtrac UPA-150 manufactured by Nikkiso Co., Ltd., and the solid content concentration (mass concentration) in the measurement sample was 0.01 mass. It was 120 nm as a result of measuring using the sample diluted with the pure water so that it might become%.

<Post-treatment liquid>
-Preparation of post-treatment liquid 1-
Water-soluble organic solvent B: 20.0 g of glycerin (SP value: 16.4 (cal / cm ³ ) ^1/2 ), water-soluble organic solvent C: 1,3 butanediol (SP value: 12.8 (cal / cm ³ ) ^1/2 ) 10.0 g, urethane resin a: trade name: Superflex SF-210 (Daiichi Kogyo Seiyaku Co., Ltd.) 37.5 g, polyethylene wax emulsion A (trade name: Nopcoat MS-40, San Nopco) 5.0 g, surfactant 0.4 g shown in the above formula (i), N-octyl-2-pyrrolidone 1.2 g, octanediol 2.0 g, 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 those described in Examples 2 to 15 of Tables 2 to 5 or the columns of Comparative Examples 1 to 6. . The ink used in Examples 2 to 15 and Comparative Examples 1 to 6 is 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 amounts of resin acid groups. The SP value is calculated by the method described in the embodiment. Moreover, the resin acid group amount of Example 13 is calculated by the following formula.
(Acid group amount of polyester urethane resin a 0.74 (meq / g) × 20 (mass%) + Acrylic resin A acid group amount 0.4 (meq / g) × 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 , Sankyo Chemical Co., Ltd.)
* Polyester urethane resin a: Product name: Superflex SF-210 (Daiichi Kogyo Seiyaku Co., Ltd.)
* Polyether urethane resin b: Trade name: NeoRezR-600 (manufactured by Enomoto Kasei Co., Ltd.)
* Urethane acrylic resin c: Trade name: NeoPacR 9699 (manufactured by Enomoto Kasei Co., Ltd.)
* Polyether urethane resin d: Trade name: Permarin UA00 (manufactured by Sanyo Chemical Industries)
* Polyether urethane resin e: Trade name: SU-100N (manufactured by Chuo Rika Kogyo Co., Ltd.)
* Polyester urethane resin f: Trade name: NeoRezR-2170 (manufactured by Enomoto Kasei Co., Ltd.)
* Acrylic resin A: Trade name: NeoCryl A1094 (Enomoto Kasei Co., Ltd.)
* Acrylic resin B: Trade name: NeoCryl A662 (Enomoto Kasei Co., Ltd.)
* Acrylic resin C: Trade name: Mobile LDM6740 (manufactured by Nippon Synthetic Chemical Co., Ltd.)
* Acrylic resin D: Trade name: Mobile 972 (manufactured by Nippon Synthetic Chemical)
* Acrylic resin E: Trade name: TOCRYLW4322 (manufactured by Toyochem)
* Polyethylene-based wax emulsion A: Trade name: Nopcomal MS-40 (manufactured by San Nopco, melting point: 79 ° C.)
* Polyethylene wax emulsion B: Product name: Nopcoat PEM-17 (San Nopco, melting point: 105 ° C)
* Isocyanate group-containing resin: Trade name: Elastron E-37 (Daiichi Kogyo Seiyaku Co., Ltd.)
* A compound represented by the following formula (i) which is a fluorosurfactant (trade name: Unidyne DSN-403N), manufactured by Daikin Industries, Ltd.

<Image forming method>
The ink described in Table 1 is ejected onto a recording medium (trade name: Mirror Coat Gold, Oji Paper Co., Ltd .: glossiness 60 of paper) by an image forming apparatus (trade name: IPSIO GXe5500, manufactured by Ricoh Co., Ltd.) An unfixed solid image of 3 cm square formed with a pattern was formed, and after 1.5 seconds, after Examples 1 to 15 described in Tables 2 to 5 or Comparative Examples 1 to 6 on the surface of the solid image The processing liquid was discharged by the image forming apparatus. Then, it was dried at 90 ° C. for 2 minutes with hot air and a drum heater to obtain a fixed image. In Example 11, before applying the post-treatment liquid, it was dried at 90 ° C. for 2 minutes with hot air and a drum heater, and then the post-treatment liquid of Example 11 was applied to the surface of the solid image. Was discharged. 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 with a dot pattern by the above method was measured with a gloss meter (manufactured by BYK Gardener, micro-TRI-gloss). The lower the gloss value of the image, the better the matte printing and mat printing. In addition, those having a glossiness of 45 or less can be used as a low glossiness in practice, and a glossiness of 40 or less is more preferable. .

<< Image scratch resistance >>
The solid portion of the solid image of 3 cm square in the image formed by the above method is rubbed by attaching a cloth to a friction tester (trade name: CLOCK METER, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and applied to the cloth after rubbing. The transfer density of the ink was measured with a spectrocolorimetric densitometer (trade name: X-Rite 939, manufactured by X-Rite). The smaller the transfer density, the better the image scratch resistance. If the transfer density is less than 0.20, it can be used practically without any problem.

<< Discharge stability >>
After printing a solid portion of a 3 cm square solid image by the above method, the recording head is left uncaped for 1 hour, and then the same image is recorded again to measure the number of non-ejection nozzles. Based on the evaluation criteria, “ejection stability” was evaluated. In addition, when the following evaluation criteria are "(circle)", it can be used practically without a problem.

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

<Blocking resistance>
An unrecorded recording medium is placed on the recording surface of a solid portion of a 3 cm square solid image recorded by the above method, and this is sandwiched between two 10 × 10 cm square glass plates. / M ² , and left under environmental conditions of 40 ° C. and 90% RH for 24 hours. Thereafter, it was left at room temperature (25 ° C.) for 2 hours, and the state of sticking of the recording media when peeled off was visually observed and evaluated according to the following evaluation criteria. In addition, it can be used without a problem practically that the following evaluation criteria are "(circle)" or more.

-Evaluation criteria-
○: No blocking (Slightly sticking. There are slight scratches on the surface of the sample)
X: Blocking (adherently fused on the adjacent surface. State that is difficult to peel off)

JP 2008-213151 A

203 Recording medium 300 Inkjet recording apparatus 301 Recording medium transport unit 302 Pre-processing step unit 303 Pre-processing post-drying unit 304 Image forming processing units 304K, 304C, 304M, 304Y Recording head 305 Post-processing step units 305K-1, 305K-2, 305K-3, 305K-4 Head unit 306 Post-processing post-drying unit 307 Paper feeding device 308 Winding device 309 Nozzle surface 310 Printing nozzle

Claims (10)

An ink, and a treatment liquid for the recording medium to which the ink is applied,
The ink contains a first solution containing an organic solvent and water,
The treatment liquid contains at least one of an organic solvent, a second solution containing water, urethane resin particles, and acrylic resin particles,
The solubility parameter of the treatment liquid in the second solution is 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter of the ink in the first solution,
An ink and a treatment liquid set in which the amount of acid groups 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. A set of processing solutions. The set of the ink and the treatment liquid according to claim 1 or 2, wherein a 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 the ink and the treatment liquid according to any one of claims 1 to 3, wherein the resin particles in the treatment liquid are urethane resin particles. The ink and treatment liquid set according to claim 4, wherein the urethane resin particles are polyether-based urethane resin particles. An ink application step of applying an ink containing a first solution containing an organic solvent and water to a recording medium;
A treatment liquid application step of applying a treatment liquid containing at least one of a second solution containing an organic solvent and water, urethane resin particles, and acrylic resin particles to the surface of the recording medium to which the ink has been applied. And having
The solubility parameter of the treatment liquid in the second solution is 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter of the ink in the first solution,
The recording method wherein the amount of acid groups 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 there is no drying step for drying the ink between the ink application step and the treatment liquid application step. An ink applying means for applying an ink containing a first solution containing an organic solvent and water to a recording medium;
A treatment liquid application means for applying a treatment liquid containing at least one of an organic solvent and a second solution containing water, urethane resin particles, and acrylic resin particles to the surface of the recording medium to which the ink has been applied. And having
The solubility parameter of the treatment liquid in the second solution is 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter of the ink in the first solution,
The recording apparatus wherein the amount of acid groups 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 apparatus according to claim 8, wherein a drying unit that dries the ink is not provided in a conveyance path of the recording medium between the ink application unit and the treatment liquid application unit. An organic solvent and a recording medium provided with an ink containing a first solution containing water;
Containing at least one of an organic solvent, a second solution containing water, urethane resin particles, and acrylic resin particles;
The solubility parameter in the second solution is 1.5 (cal / cm ³ ) ^1/2 or more higher than the solubility parameter in the first solution,
The treatment liquid wherein the acid group amount of at least one of the urethane resin particles and the acrylic resin particles is 0.3 meq / g or more.

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