JP2017218479A - Ink, ink container, inkjet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose an ink having improved image density, ejection stability under discontinuous ejection conditions, and storage stability. An ink containing water, a coloring material, a first organic solvent, and a second organic solvent, wherein the first organic solvent is 1,2-hexanediol and with respect to the total amount of the ink. The second organic solvent is 2-ethyl-1,3-hexanediol, 3-methyl-1,3-butanediol, 1,2-, which is contained in an amount of 10.0% by mass or more and 40.0% by mass or less. At least one selected from propanediol, 1,3-propanediol, 2-pyrrolidone, and glycerin, the mass of the second organic solvent (S2) with respect to the first organic solvent (S1) in the ink. An ink having a ratio (S2 / S1) of S2 / S1 ≦ 3/10. [Selection diagram] None

Description

  The present invention relates to ink, an ink container, and an ink jet recording apparatus.

The ink used for plain paper and various coated papers is required to have various qualities and functions, but various studies have been made to improve the image density, which is a basic quality.
In particular, there is a strong demand from the market for an improvement in image density of plain inkjet ink.

In general, it is said that the dynamic surface tension should be lowered to improve the image density. Fluorine-based surfactants and silicone-based surfactants that tend to lower the surface tension can reduce the static surface tension by adding a small amount, but the dynamic surface tension is difficult to decrease. This is because the surfactant stabilizes by forming micelles in the ink, and it is difficult to contribute to a decrease in dynamic surface tension. In particular, it is difficult to reduce the dynamic surface tension with a fluorosurfactant.
Silicone surfactants can easily reduce the dynamic surface tension by adjusting the molecular structure as compared with fluorine surfactants.
However, when a surfactant capable of lowering the dynamic surface tension is added, the static surface tension is too low and the meniscus formation in the nozzle becomes unstable, or there are defects such as bleeding and show-through on the paper. It is easy to become.

On the other hand, acetylene glycol surfactants are known to have a relatively low dynamic surface tension and a small difference from static surface tension.
However, acetylene glycol surfactants exhibit good properties when used in dye-based inks, but when used in pigment-dispersed inks, they tend to destabilize pigment dispersion and cause aggregation, etc. Ejection defects such as nozzle bending are likely to occur. It is also known that wetting and spreading on coated paper or film is insufficient.

In Patent Document 1, (a) a specific pigment, (b) water, (c) acetylene glycol and / or acetylene alcohol surfactant, di (tri) ethylene glycol monobutyl ether and / or (di) propylene An attempt is made to improve the printing quality for plain paper or recycled paper using an aqueous ink containing glycol monobutyl ether and one or more selected from the group consisting of 1,2-alkylene glycol.
The preferable addition amount of 1,2-alkylene glycol is 10% by mass or less, and in the examples, there is an example in which 1,2-hexanediol is added by 4% by mass.
In Patent Document 2, a specific clogging preventing agent and a penetrating agent are selected from acetylene glycol surfactants, acetylene alcohol surfactants, silicone surfactants, alkylene glycol monoalkyl ethers, and 1,2-alkylene glycols. One or more selected types are used, and a pigment is wrapped with a polymer to make an ink, thereby improving storage stability.

In Patent Document 3, a surfactant is a silicone having at least one acrylic group in its structure, and a hydrophobic ether such as a polyvinyl chloride sheet is used in combination with glycol ethers and alkanediols as water-soluble organic solvents. It is trying to obtain high print quality with respect to highly difficult to absorb media.
In Patent Document 4, an ink composition containing an acetylene glycol surfactant and a co-solvent such as a polyhydric alcohol and having a specific dynamic surface tension will achieve high print quality with respect to a hardly absorbent medium. It is said.
Patent Document 5 discloses an ink containing a vinyl polymer having an acid value of 200 KOHmg / g or more and having a specific viscosity and dynamic surface tension in order to obtain high print quality with respect to a hardly absorbent medium. Yes. Furthermore, the continuous discharge stability is improved by using a specific alkanediol.

However, the above means cannot be said to be sufficient for ejection failure due to discontinuous ejection conditions.
The present invention proposes an ink with improved image density, which is not sufficiently satisfied by the prior art, improved ejection stability under discontinuous ejection conditions, and storage stability.
The first object of the present invention is to improve the image density, and particularly to improve the image density when an image is formed on plain paper by the ink jet method.
The second purpose is to improve the storage stability of the pigment dispersed in the ink.
The third purpose is to improve drying and discharge drying.

As a result of intensive studies, the present inventors have found that the above problems can be solved by the ink described in (1) below, and have reached the present invention. That is, the present invention is as follows.
(1) An ink containing water, a coloring material, a first organic solvent, and a second organic solvent,
The first organic solvent is 1,2-hexanediol and is contained in an amount of 10.0% by mass or more and 40.0% by mass or less based on the total amount of the ink;
The second organic solvent is 2-ethyl-1,3-hexanediol, 3-methyl-1,3-butanediol, 1,2-propanediol, 1,3-propanediol, 2-pyrrolidone, and glycerin. At least one selected from
The ink in which the mass ratio (S2 / S1) of the second organic solvent (S2) to the first organic solvent (S1) in the ink is S2 / S1 ≦ 3/10.

  According to the present invention, it is possible to provide an ink with improved image density, improved ejection stability under discontinuous ejection conditions, and storage stability.

It is a figure which shows an example of the recording device of this invention. FIG. 4 is a perspective view of an ink storage container that stores ink.

The ink of the present invention is
An ink comprising water, a coloring material, a first organic solvent, and a second organic solvent,
The first organic solvent is 1,2-hexanediol and is contained in an amount of 10.0% by mass or more and 40.0% by mass or less based on the total amount of the ink;
The second organic solvent is 2-ethyl-1,3-hexanediol, 3-methyl-1,3-butanediol, 1,2-propanediol, 1,3-propanediol, 2-pyrrolidone, and glycerin. At least one selected from
The mass ratio (S2 / S1) of the second organic solvent (S2) to the first organic solvent (S1) in the ink is S2 / S1 ≦ 3/10.

In order to lower the dynamic surface tension of the ink, it is preferable to use a water-soluble organic solvent having a low surface tension. Since the surfactant requires time to move to a new interface formed when ink droplets are ejected, it is preferable to use a water-soluble organic solvent that does not require transfer time.
Of the water-soluble organic solvents having a low surface tension, 1,2-hexanediol is used as the first organic solvent in the present invention. 1,2 hexanediol can reduce the difference between the dynamic surface tension and the static surface tension of the ink, is stable, and tends to stabilize meniscus formation in the discharge nozzle. In addition, there is little variation in droplet diameter when landing on the printing substrate, and image density unevenness and variation are small. In addition, the ink is hardly deteriorated after long-term storage without impairing the dispersion stability of the pigment dispersed in the ink.
The content of 1,2 hexanediol is 10.0% by mass or more and 40.0% by mass or less, and preferably 12.0% by mass or more and 30.0% by mass or less with respect to the total amount of the ink. The required dynamic surface tension can be obtained within this range. In addition, it is easy to balance the viscosity and moisture retention required for an ink jet printer in combination with other organic solvents used for the purpose of improving moisture retention.

The ink of the present invention contains, as the second organic solvent, 2-ethyl-1,3-hexanediol (EHD), 3-methyl-1,3-butanediol (MBD), 1,2-propanediol (1, 2PD), 1,3-propanediol (1,3PD), 2-pyrrolidone, and at least one organic solvent selected from glycerin.
These second organic solvents have a high effect of improving moisture retention without greatly changing the surface tension.

  It is important that the mass ratio of the second organic solvent amount S2 to the first organic solvent amount S1 is S2 / S1 ≦ 3/10. Preferably, 1/10 ≦ S2 / S1 ≦ 2.5 / 10. If 1/10 ≦ S2 / S1, the discharge stability increases. If S2 / S1 ≦ 2.5 / 10, it is easy to adjust the dynamic surface tension and viscosity.

  The content of the second organic solvent is preferably 1.0% by mass to 12.0% by mass. More preferably, it is 2.0 mass% to 10.0 mass%. When the content is increased, the moisture retention is improved and the ejection stability is improved. When the discharge stability at the time of continuous discharge is expected, the effect is effective from about 1.0% by mass, and when the discharge stability at the time of discontinuous discharge is expected, 2.0% by mass or more is preferable. If the content is increased, it may be difficult to adjust the viscosity and the surface tension. Therefore, if the content is 10.0% by mass or less, it is easy to adjust the desired characteristics.

  Furthermore, the ink of the present invention preferably has a dynamic surface tension of 33 mN / m or less at a bubble life time of 15 msec at 25.0 ° C. according to the maximum bubble pressure method.

When forming an image on a printing substrate such as uncoated paper, coated paper, or polymer film by the inkjet method, when trying to obtain a printed matter with excellent color density and color development and improved image bleeding, the ink It is known that reducing the dynamic surface tension is good.
Ink-jet ink deposits and dries on a printing substrate in a short time of tens of milliseconds or less, with a small droplet of about 10 PL. In order for the ink to exhibit good color developability, it is necessary to get wet on the printing substrate in a short time. An ink having a low dynamic surface tension, specifically, an ink having a bubble lifetime value of 15 msec by the maximum bubble pressure method of 33 mN / m or less is preferred. More preferably, it is 31 mN / m or less.
When the dynamic surface tension is within the above range, the wettability of the ink with respect to the printing substrate can be improved, the surface coverage of the printing substrate with ink droplets can be increased, and the image density can be improved.
The dynamic surface tension is preferably 25 mN / m or more. By not reducing the dynamic surface tension too much, it becomes easy to control the ejection stability of ink droplets and appropriate penetration into the printing substrate.

The ink of the present invention preferably contains a nonionic fluorosurfactant and has a static surface tension of 25 mN / m or more at 25.0 ° C. By not reducing the static surface tension too much, it becomes easy to control the ejection stability of ink droplets and appropriate penetration into the printing substrate.
In particular, by using the above-mentioned fluorine-based surfactant, the penetrability is remarkably improved, whereby the color boundary blur is reduced, the color developability is improved, and the ink with less text blur is obtained.
As the fluorosurfactant used in the present invention, commercially available ones can be used, S-141, S-145 (manufactured by Asahi Glass Co., Ltd.), FC-170C, FC-430, Fluorard- FC4430 (manufactured by Sumitomo 3M), FSO, FSO-100, FSN, FSN-100, FS-300 (manufactured by Dupont), FT-250, 251 (manufactured by Neos), and the like. Among them, FSO, FSO-100, FSN, FSN-100, and FS-300 manufactured by Dupont are preferable because they can provide good print quality and storage stability. The said fluorosurfactant can be used individually or in mixture of 2 or more types.

  The content of the fluorosurfactant is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less with respect to the ink for inkjet recording. If the amount is less than 0.1% by mass, there is no significant effect on the permeability, and if it is added in excess of 10% by mass, the viscosity increases, aggregates, etc. when stored at high temperature, and the reliability deteriorates. There is.

  The cloud point (JIS K2269) of the fluorosurfactant is preferably 50 ° C. or higher, more preferably 60 ° C. or higher. When the cloud point is less than 50 ° C., the stability against heat is weak, and an ink prepared using the cloud point may increase in viscosity, aggregate, etc. when stored at a high temperature, and may deteriorate in reliability.

  The static surface tension (25 ° C.) of a 0.1% (mass) aqueous solution of the fluorosurfactant is preferably 10 mN / m or more and 40 mN / m or less, more preferably 10 mN / m or more and 30 mN / m. It is as follows. According to this surface tension range, the ink permeability of the image support such as paper is increased, and the drying property of the printed image is accelerated. When the static surface tension exceeds 40 mN / m, the dynamic tension is high, so that the drying property when the ink lands on the paper is deteriorated.

<Ink>
Hereinafter, water, color materials, resins, additives, and the like used for the ink will be described.

<Water>
The water content 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 90% by mass or less, and 20% by mass from the viewpoint of ink drying property and ejection reliability. % To 60% by mass is more preferable.

<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.
Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver, and metallic pigments.
Carbon black produced by known methods such as contact method, furnace method, thermal method in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, 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, quinofullerone pigments, etc.) 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 disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of dispersing the pigment surface by coating with a resin, a method of dispersing using a dispersant, Etc.
Examples of a method for introducing a hydrophilic functional group into a pigment to form a self-dispersing pigment include a self-dispersing pigment that can be dispersed in water by adding a functional group such as a sulfone group or a carboxyl group to the pigment (for example, carbon). Can be used.
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 can be dispersed in water can be used. 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 dispersing water, a pigment, a pigment dispersant, and other components as required, 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 converted. 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 preventive agent, 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 the 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.

（但し、一般式（Ｓ−１）式中、ｍ、ｎ、ａ、及びｂは整数を表わす。Ｒ及びＲ’はアルキル基、アルキレン基を表わす。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ−６１８、ＫＦ−６４２、ＫＦ−６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ−ＳＳ−５６０２、ＳＳ−１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ−２１０５、ＦＺ−２１１８、ＦＺ−２１５４、ＦＺ−２１６１、ＦＺ−２１６２、ＦＺ−２１６３、ＦＺ−２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ−３３、ＢＹＫ−３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）などが挙げられる。 The silicone 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.
There is no restriction | limiting in particular as said polyether modified silicone surfactant, According to the objective, it can select suitably, For example, the polyalkylene oxide structure represented by a general formula (S-1) type | formula is dimethylpolyethylene. Examples thereof include those introduced into the side chain of Si part of siloxane.

(In the general formula (S-1), m, n, a, and b represent integers. R and R ′ represent an alkyl group and an alkylene 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.

上記一般式（Ｆ−１）で表される化合物において、水溶性を付与するためにｍは０〜１０の整数が好ましく、ｎは０〜４０の整数が好ましい。
一般式（Ｆ−２）
Ｃ_nＦ_2n+1−ＣＨ₂ＣＨ(ＯＨ)ＣＨ₂−Ｏ−(ＣＨ₂ＣＨ₂Ｏ)_a−Ｙ
上記一般式（Ｆ−２）で表される化合物において、ＹはＨ、又はＣ_ｎＦ_2n+1でｎは１〜６の整数、又はＣＨ₂ＣＨ(ＯＨ)ＣＨ₂−ＣnＦ_2n+1でｎは４〜６の整数、又はＣ_pＨ_2p+1でｐは１〜１９の整数である。ａは４〜１４の整数である。
上記のフッ素系界面活性剤としては市販品を使用してもよい。この市販品としては、例えば、サーフロンＳ−１１１、Ｓ−１１２、Ｓ−１１３、Ｓ−１２１、Ｓ−１３１、Ｓ−１３２、Ｓ−１４１、Ｓ−１４５（いずれも、旭硝子株式会社製）；フルラードＦＣ−９３、ＦＣ−９５、ＦＣ−９８、ＦＣ−１２９、ＦＣ−１３５、ＦＣ−１７０Ｃ、ＦＣ−４３０、ＦＣ−４３１（いずれも、住友スリーエム株式会社製）；メガファックＦ−４７０、Ｆ−１４０５、Ｆ−４７４（いずれも、大日本インキ化学工業株式会社製）；ゾニール（Ｚｏｎｙｌ）ＴＢＳ、ＦＳＰ、ＦＳＡ、ＦＳＮ−１００、ＦＳＮ、ＦＳＯ−１００、ＦＳＯ、ＦＳ−３００、ＵＲ（いずれも、ＤｕＰｏｎｔ社製）；ＦＴ−１１０、ＦＴ−２５０、ＦＴ−２５１、ＦＴ−４００Ｓ、ＦＴ−１５０、ＦＴ−４００ＳＷ（いずれも、株式会社ネオス社製）、ポリフォックスＰＦ−１３６Ａ，ＰＦ−１５６Ａ、ＰＦ−１５１Ｎ、ＰＦ−１５４、ＰＦ−１５９（オムノバ社製）、ユニダインＤＳＮ-４０３Ｎ（ダイキン工業株式会社製）などが挙げられ、これらの中でも、良好な印字品質、特に発色性、紙に対する浸透性、濡れ性、均染性が著しく向上する点から、Ｄｕ Ｐｏｎｔ社製のＦＳ−３００、株式会社ネオス製のＦＴ−１１０、ＦＴ−２５０、ＦＴ−２５１、ＦＴ−４００Ｓ、ＦＴ−１５０、ＦＴ−４００ＳＷ、オムノバ社製のポリフォックスＰＦ−１５１Ｎ及びダイキン工業株式会社製のユニダインＤＳＮ−４０３Ｎが特に好ましい。 As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of the fluorosurfactant include perfluoroalkyl phosphate compounds, perfluoroalkylethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because of its low foaming property, and in particular, fluorine-based compounds represented by the general formulas (F-1) and (F-2) A surfactant is preferred.

In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
Formula (F-2)
_{C n F 2n + 1 -CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y
In the compound represented by the general formula (F-2), Y is H, or _C n F _{2n + 1,} n is an integer of 1 to 6, or _{CH 2 CH (OH) CH 2} -CnF 2n + 1 n is 4-6 integer, or p is C _p H _{2p + 1} is 1 to 19 integer. a is an integer of 4-14.
A commercial item may be used as said fluorosurfactant. As this commercial item, for example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F -1405, F-474 (all manufactured by Dainippon Ink & Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all are corporations) (Manufactured by Male), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (Omnova), Unidyne DSN-403N (produced by Daikin Industries, Ltd.), and the like. Among these, FS-300 manufactured by Du Pont, FT-110, FT-250 manufactured by Neos Co., Ltd., and the like, have excellent print quality, particularly color developability, paper permeability, wettability, and leveling. FT-251, FT-400S, FT-150, FT-400SW, Polyfox PF-151N manufactured by Omninova, and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferable.

  The total content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. From the viewpoint of excellent wettability and ejection stability and improving image quality, 0.001. The mass% is preferably 5% by mass or less and more preferably 0.05% by mass or more and 5% by mass or less.

<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.

<Ink container>
The ink storage container of the present invention includes an ink storage portion that stores the ink of the present invention in a container, and may further constitute other members appropriately selected as necessary.
The shape, structure, size, and material of the container are not particularly limited and can be appropriately selected according to the purpose. Preferred examples include those having at least an ink containing portion formed of an aluminum laminate film, a resin film, or the like.

<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.

<Recorded material>
The ink recorded matter of the present invention has an image formed using the ink of the present invention on a recording medium.
Recording can be performed by recording with an inkjet recording apparatus and an inkjet recording method.

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

  The method of using the ink is not limited to the ink jet recording method, and can be widely used. Besides the ink jet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be applied to printed materials, paints, coating materials, foundations and the like. Furthermore, it can be used not only to form two-dimensional characters and images using ink, but also as a three-dimensional modeling material for forming a three-dimensional three-dimensional image (three-dimensional modeled object).
A known three-dimensional modeling apparatus for modeling a three-dimensional model can be used, and is not particularly limited. For example, a three-dimensional modeling apparatus including an ink storage unit, a supply unit, a discharge unit, a drying unit, or the like is used. be able to. The three-dimensional structure includes a three-dimensional structure obtained by repeatedly applying ink. Further, a molded product obtained by processing a structure provided with ink on a substrate such as a recording medium is also included. The molded product is obtained by subjecting a recorded material or a structure formed in a sheet shape or a film shape to a molding process such as heat stretching or punching, for example, an automobile, an OA device, an electric -It is suitably used for applications in which surfaces are decorated after decorating, such as meters for electronic devices, cameras, etc., and panels for operation units.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these Examples.

Preparation Example 1 (Preparation of surface-treated carbon black pigment dispersion)
BET specific surface area of 220 m ² / g, carbon black 90g of DBP adsorption amount 100 ml / 100 g, was added to 2.5 N sulfuric acid solution of sodium 3000 ml, temperature of 60 ° C., and stirred at a speed 300 rpm, oxidized and reacted for 10 hours Was done.
The reaction solution was filtered, and the carbon black separated by filtration was neutralized with a sodium hydroxide solution and subjected to ultrafiltration.
The obtained carbon black was washed with water and dried, and then dispersed in pure water so that the amount of carbon black was 20% by mass to obtain a carbon black pigment dispersion.

Examples 1-8, Comparative Examples 1-4
Ink Production Examples Inks of Examples 1 to 8 and Comparative Examples 1 to 4 were prepared according to the formulations shown in Table 1. In Table 1, the numerical value of each material indicates part by mass.
Stir for 1 hour and 30 minutes after adding all ingredients. Then, it filtered with the membrane filter with the hole diameter of 0.8 micrometer, and obtained the ink.
FS-300 is a nonionic fluorosurfactant manufactured by DuPont, and has a static surface tension (25 ° C.) in a 0.1% by mass aqueous solution in the range of 10 mN / m to 40 mN / m.
BYK-3400 is a silicon-based wetting agent manufactured by Big Chemie.

The following evaluation was performed about the obtained ink.
[Ink evaluation method]
<Dynamic surface tension>
A Dyna Tester manufactured by SITA was used for the measurement of the dynamic surface tension of the ink.
The measurement conditions were 25.0 ° C. and bubble lifetime 15 msec.

<Static surface tension>
For measuring the static surface tension of the ink, an automatic surface tension measuring machine DY-300 manufactured by Kyowa Interface Science Co., Ltd. was used. A constant temperature water tank was connected to the main body, and 25.0 ° C. warm water was circulated for use.

<Average particle size>
The average particle diameter (D50%) of the ink was measured with a particle size distribution measuring device (Nikki Co., Ltd., Nanotrac UPA-EX150).

<Viscosity>
The viscosity of the ink is measured using a rheometer (MCR301 manufactured by Anton Paar) in an environment of 25 ° C. and 50% RH. At this time, a gap (Gap) is set to 50 μm using a flat plate having a diameter of 5 (cm). The viscosity at a shear rate of 100 (1 / s) was measured.

<Image formation>
For the image formation, an ink jet printer IPSiO SG3100 manufactured by Ricoh Co., Ltd. was used.

<Image density>
For the image density, a spectrocolorimetric densitometer model 938 manufactured by X-Rite was used.
Using the inkjet printer, a document in which six 10 mm square black solid patches were evenly arranged was punched out on My Paper (manufactured by NBS Ricoh Co., Ltd.), and the image density of the black solid portion was measured.
The print mode is “plain paper fast” in the driver settings.

<Continuous discharge stability>
Using the ink jet printer, it was confirmed that there was no ejection disturbance by sticking out a chart that fills 100% area of A4 size paper created with Microsoft Word 2000 with a solid image on My Paper (manufactured by NBS Ricoh Co., Ltd.). .
Thereafter, the maintenance cap of the printer was separated from the nozzles to open the nozzles, and then left in an environment of 40 ° C. and 10% RH for 3 hours.
Thereafter, the same chart as that in the initial stage was printed, and ejection disturbance of each nozzle was evaluated according to the following criteria. The print mode used was a driver attached to the printer, in which the “plain paper standard fast” mode was changed to “no color correction” from the user settings for plain paper.
〔Evaluation criteria〕
○: Discharge all nozzles Δ: Less than 10 nozzles that do not discharge ×: 10 or more nozzles that do not discharge

<Intermittent discharge stability>
A chart that prints an area of 0.1% of A4 size paper per color created by Microsoft Word 2000 as a line image by using the inkjet printer and varying the drive voltage of the piezo element so that the amount of ink discharged is uniform. 250 sheets were printed on My Paper (manufactured by NBS Ricoh Co., Ltd.), and it was confirmed that there was no discharge disturbance.
〔Evaluation criteria〕
○: Discharge all nozzles Δ: Less than 10 nozzles that do not discharge ×: 10 or more nozzles that do not discharge

<Storage stability>
200 g of the prepared ink was sealed in a glass bottle with a capacity of 500 CC, and stored in a constant temperature bath at 40 ° C. for 1 month. The average particle size and viscosity after storage were measured in the same manner as the measurement of the average particle size and the viscosity.

The evaluation results are shown in Table 2.

  As shown in Table 2, the ink of the present invention exhibits high image density, has little change in particle size and viscosity during storage, and is excellent in ejection stability.

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

JP 2004-339282 A JP 2004-143387 A JP 2013-189599 A Special table 2015-515510 gazette JP 2014-224248 A

Claims (9)

An ink comprising water, a coloring material, a first organic solvent, and a second organic solvent,
The first organic solvent is 1,2-hexanediol and is contained in an amount of 10.0% by mass or more and 40.0% by mass or less based on the total amount of the ink;
The second organic solvent is 2-ethyl-1,3-hexanediol, 3-methyl-1,3-butanediol, 1,2-propanediol, 1,3-propanediol, 2-pyrrolidone, and glycerin. At least one selected from
The ink in which the mass ratio (S2 / S1) of the second organic solvent (S2) to the first organic solvent (S1) in the ink is S2 / S1 ≦ 3/10.   2. The ink according to claim 1, wherein the ink has a dynamic surface tension of 33 mN / m or less at 25.0 ° C. when a bubble lifetime is 15 msec by a maximum bubble pressure method. The ink contains a nonionic fluorosurfactant,
The ink according to claim 1 or 2, wherein a static surface tension is 25 mN / m or more at 25.0 ° C.   The ink according to any one of claims 1 to 3, wherein a content of the first organic solvent with respect to the total amount of the ink is 12.0 mass% or more and 30.0 mass% or less.   The ink according to any one of claims 1 to 4, wherein the mass ratio (S2 / S1) is 1 / 10≤S2 / S1≤2.5 / 10.   The ink according to any one of claims 1 to 5, wherein a content of the second organic solvent with respect to the total amount of the ink is 1.0% by mass or more and 12.0% by mass or less.   4. The ink according to claim 3, wherein a static surface tension (25 ° C.) in a 0.1% by mass aqueous solution of the nonionic fluorosurfactant is 10 mN / m or more and 40 mN / m or less.   An ink storage container in which the ink according to claim 1 is stored in a container. An ink container according to claim 8,
Discharge means for discharging ink supplied from the ink container;
An ink jet recording apparatus.

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