JP2021014027A - Ink discharge head, image formation device, and image formation method - Google Patents

Abstract

To provide an image formation device that prevents the occurrence of beading, and has excellent discharge stability when left to stand in an uncapped state for a long time.SOLUTION: An image formation device 400 has an ink discharge head 434 provided with a nozzle plate having an ink-repellent film, and an ink having a compound of general formula (1), a colorant, and a surfactant different in material from the ink-repellent film. In the general formula (1), n is an average value and an integer of 2-40.SELECTED DRAWING: Figure 1

Description

The present invention relates to an ink ejection head, an image forming apparatus, and an image forming method.

The inkjet recording method, which prints using an inkjet recording device having an ink ejection head, is widely used as a home printer because of its low noise, simple process, and easy colorization. Further, in recent years, the inkjet recording method has been expanded to commercial printing because of its advantages such as variable printing and support for a wide range of recording media.

As an ink used in the above-mentioned inkjet recording method, an aqueous pigment ink in which a pigment is made into fine particles and dispersed in water is attracting attention. Since the pigment has a composition similar to that of a colorant used in general commercial printing inks, it is expected that the texture of printed matter can be brought closer to that of commercial printing. However, when recording on coated paper for commercial printing or publication printing using the water-based pigment ink, there is a problem that the ink cannot be absorbed in time and density unevenness (beading) of a solid image portion occurs.

It is known that the occurrence of beading can be suppressed by lowering the surface tension of the ink, but if this is done, the ink tends to wet and spread on the ink-repellent film of the nozzle plate of the ink ejection head, causing nozzle stains. There is a problem that the discharge stability is lowered.
Therefore, for example, a method has been proposed in which the suppression of beading and the discharge stability during continuous discharge are achieved by optimizing the balance of surface tension (see, for example, Patent Document 1).

An object of the present invention is to provide an image forming apparatus capable of suppressing the occurrence of beading and having good ejection stability when the decap is left for a long time.

The image forming apparatus of the present invention as a means for solving the above-mentioned problems includes an ink ejection head including a nozzle plate having an ink-repellent film, a compound represented by the following general formula (1), a coloring material, and the repellent. It has an ink containing a surfactant having a material different from that of the ink film.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.

According to the present invention, it is an object of the present invention to provide an image forming apparatus capable of suppressing the occurrence of beading and having good ejection stability when the decap is left for a long time.

FIG. 1 is a schematic view showing an example of an image forming apparatus used in the image forming method of the present invention. FIG. 2 is a schematic perspective view of the main tank in the image forming apparatus. Here, an example of the ink ejection head used in the present invention will be described with reference to FIGS. 3 to 5. FIG. 3 is an exploded perspective explanatory view of the ink ejection head used in the image forming apparatus of the present invention. FIG. 4 is an explanatory cross-sectional view taken along a direction (longitudinal direction of the liquid chamber) orthogonal to the nozzle arrangement direction of the ink ejection head of FIG. FIG. 5 is an explanatory cross-sectional view taken along the nozzle arrangement direction (short side direction of the liquid chamber) of the ink ejection head of FIG.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention includes an ink ejection head including a nozzle plate having an ink-repellent film, a compound represented by the following general formula (1), a coloring material, and a surfactant having a material different from the ink-repellent film. It has an ink containing, and further has other means as needed.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.

The image forming method of the present invention is different from the compound represented by the general formula (1), the coloring material, and the ink-repellent film from the ink ejection head provided with the nozzle plate having the ink-repellent film with respect to the recording medium. It includes an ink ejection step of ejecting ink containing a surfactant having a material, and further includes other steps as necessary.

The conventional technique has a problem that the discharge stability is lowered when the decap is left for a long time.

In the present invention, the contact angle of the ink with respect to the recording medium is reduced by including the compound having the structure of the general formula (1). Then, the ink spreads well in wetness, and it becomes possible to suppress the occurrence of beading.
While the occurrence of beading can be suppressed, the ink spreads on the nozzle plate. As a result, there is a problem that the ink sticking to the nozzle plate is deteriorated.
Therefore, by incorporating a surfactant having a material different from the ink-repellent film of the nozzle plate into the ink, it is possible to make the ink difficult to wet and spread on the nozzle plate. Since the ink easily wets and spreads on the nozzle plate only with the compound of the above general formula (1), and even if only a surfactant having the same material as the ink-repellent film of the nozzle plate is added, the material is the same as the ink-repellent film. It only increases the affinity and cannot suppress the wet spread of the ink.
Here, the "material different from the ink-repellent film" means an element different from the element that causes the ink-repellent property of the ink-repellent film and a compound containing the element. Therefore, it means that the main element exhibiting the ink repellency of the ink repellent film and the element possessed by the surfactant are different.
Examples of the element that causes the ink-repellent property of the ink-repellent film include a fluorine element and a silicon element.
Examples of the surfactant having a material different from that of the ink-repellent film include a fluorine surfactant, a silicone surfactant, a higher alcohol ethoxylate surfactant, and an acetylene glycol surfactant. Among these, fluorine surfactants and silicone surfactants are preferable.

In one aspect of the present invention, when the ink-repellent film of the nozzle plate contains a fluorine element, the surfactant in the ink preferably has a silicon element, and the ink-repellent film of the nozzle plate contains a silicon element. It is preferable that the surfactant in the ink has a fluorine element.
Further, when the ink-repellent film of the nozzle plate contains a fluorine element, the ink-repellent property is higher than that when the ink-repellent film contains a silicon element. Therefore, when the ink-repellent film contains a fluorine element, the surfactant in the ink is a silicon element. It is more preferable to have.
The ink-repellent film, the compound of the general formula (1) in the ink, and the surfactant can be analyzed by using GC-MS, NMR, IR, or the like.

In one aspect of the present invention, the receding contact angle of the ink with respect to the nozzle plate is preferably 35 ° or more, and more preferably 35 ° or more and 70 ° or less.
When the receding contact angle of the ink with respect to the nozzle plate is 35 ° or more, it becomes difficult for the ink-repellent film of the nozzle plate of the ink ejection head to get wet, and ejection stability can be ensured.
The receding contact angle can be measured at 25 ° C. using, for example, an automatic contact angle measuring device (DSA25, manufactured by KRUSS).

<Ink>
The ink preferably contains a compound represented by the following general formula (1), a coloring material, and a surfactant which is a material different from the ink-repellent film, and preferably contains an organic solvent, and further, if necessary. Contains other ingredients.

<< Compound represented by general formula (1) >>
The ink contains a compound represented by the following general formula (1).
However, in the general formula (1), n is an average value and is an integer of 2 to 40.

By containing the compound represented by the general formula (1), the wettability and the permeation rate can be controlled without being greatly affected by the type of recording medium. As a result, unevenness due to shading in the image can be reduced with respect to various recording media, particularly ink non-absorbent or low-absorbent recording media, and a clear image can be obtained.
The compound represented by the general formula (1) preferably has an average value of 3 to 8 from the viewpoint of specifically improving the wettability and obtaining a clearer image. Is more preferably 6.
The value of n in the general formula (1) can be measured using, for example, MALDI-TOF MS.

As the compound represented by the general formula (1), a compound synthesized as appropriate may be used, or a commercially available product may be used. Examples of the commercially available products include TRITON HW-1000 (manufactured by Dow Chemical Co., Ltd.), TERGITOR TMN-3 (manufactured by Dow Chemical Co., Ltd.), TERGITOR TMN-6 (manufactured by Dow Chemical Co., Ltd.), and TERGITOR TMN-100X (manufactured by Dow Chemical Co., Ltd.). -Chemicals), TERGITOR TMN-10 (Dow Chemicals) and the like. These may be used alone or in combination of two or more.

The content of the compound represented by the general formula (1) is preferably 0.1% by mass or more and 5% by mass or less, and more preferably 0.1% by mass or more and 3% by mass or less with respect to the total amount of the ink. When the content of the compound represented by the above general formula (1) is 0.1% by mass or more and 5% by mass or less, the occurrence of beading can be suppressed and the discharge stability when left in decap for a long time is good. Become.

<Surfactant>
The surfactant is not particularly limited as long as it has a material different from that of the ink-repellent film, and can be appropriately selected depending on the intended purpose. However, a silicone surfactant, a fluorine surfactant, and an amphoteric surfactant , Nonionic surfactants and anionic surfactants can be used, but silicone surfactants and fluorine surfactants are preferable from the viewpoint of the relationship with the ion-repellent film.
The silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, one-ended modified polydimethylsiloxane, and side chain double-ended modified polydimethylsiloxane. Those having an oxyethylene group and a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the Si side chain of dimethylsiloxane.
As the fluorine-based surfactant, for example, a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group are contained in a side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. The counter ions of the salts in these fluorine-based surfactants are Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH). _3rd grade can be mentioned.
Examples of the amphoteric tenside agent include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, and lauryldihydroxyethylbetaine.
Examples of the nonionic surfactant include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include ethylene oxide adducts of fatty acid esters and acetylene alcohols.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, polyoxyethylene alkyl ether sulfate salt and the like. These may be used alone or in combination of two or more.

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

[General formula (S-1)]
(However, in the general formula (S-1), m, n, a, and b represent integers. R and R'represent an alkyl group and an alkylene group.)

Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant, for example, KF-618, KF-642, KF-643 (manufactured by Shin-Etsu Chemical Industry Co., Ltd.), EMALEX-SS-5602, SS. -1906EX (manufactured by Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (manufactured by Toray Dow Corning Silicone Co., Ltd.), BYK -33, BYK-387 (manufactured by Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (manufactured by Toshiba Silicon Co., Ltd.) and the like.

As the fluorine-based surfactant, a compound having 2 to 16 carbon atoms substituted with fluorine is preferable, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferable.
Examples of the fluorine-based surfactant include a perfluoroalkyl phosphate compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound 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 it has low foaming property, and fluorine represented by the general formula (F-1) and the general formula (F-2) is particularly preferable. System surfactants are preferred.

[General formula (F-1)]
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.

[General 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 above 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- C _n F _{2n + 1,} where n is An integer of 4 to 6, or C _p H _{2p + 1,} where p is an integer of 1 to 19. a is an integer of 4 to 14.

Commercially available products may be used as the above-mentioned fluorine-based surfactant.
Examples of this commercially available product include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Full Lard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafuck F-470, F -1405, F-474 (all manufactured by DIC Corporation); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont) ); FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF 154, PF-159 (manufactured by Omniova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), etc. Among these, good print quality, especially color development, permeability to paper, wettability, averageness, etc. FS-300 manufactured by DuPont, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW, and Omniova manufactured by Neos Co., Ltd. from the viewpoint of significantly improving dyeability. Polyfox PF-151N and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferable.

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

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-Pentanediol, 1,5-Pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl Polyhydric alcohol alkyl ethers such as ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone. , 1,3-Dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and other nitrogen-containing heterocyclic compounds, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N- Amidos such as dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate and ethylene carbonate. And so on.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because it not only functions as a wetting agent but also has good drying properties.

As the organic solvent, a polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of the glycol ether compound include polyvalent alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers: Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether can be mentioned.
The polyol compound having 8 or more carbon atoms and the glycol ether compound can improve the permeability of the ink when paper is used as the recording medium.

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

<Water>
As the water, for example, pure water such as ion-exchanged water, ultra-filtered water, reverse osmosis water, distilled water, or ultrapure water can be used.
The water content in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of ink drying property and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass. % To 60% by mass is more preferable.

<Color material>
The colorant is not particularly limited, and pigments and dyes can be used.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Moreover, you may use a mixed crystal.
As the pigment, for example, black pigment, yellow pigment, magenta pigment, cyan pigment, white pigment, green pigment, orange pigment, glossy color pigment such as gold or silver, metallic pigment and the like can be used.
As inorganic pigments, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, carbon black produced by known methods such as contact method, furnace method, and thermal method. Can be used.
Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinofuralone pigments). , Dye chelate (for example, basic dye type chelate, acidic dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like can be used. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.

As a specific example of the pigment, for black, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11) , Metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1).
Further, for color, C.I. I. Pigment Yellow 1,3,12,13,14,17,24,34,35,37,42 (yellow iron oxide), 53,55,74,81,83,95,97,98,100,101,104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2 (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 Greens 1, 4, 7, 8, 10, 17, 18, 36 and the like.

The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.
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. Hood Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1,2,15,71,86,87,98,165,199,202, C.I. I. Dilekdo Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 and the like can be mentioned.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass or less, from the viewpoint of improving image density, good fixability and ejection stability. preferable.

To disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing the pigment, a method of dispersing using a dispersant, And so on.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a self-dispersing pigment in which a functional group such as a sulfone group or a carboxyl group is added to a pigment (for example, carbon) so that it can be dispersed in water. Etc. can be used.
As a method of coating the surface of the pigment with a resin and dispersing it, a method in which the pigment is encapsulated in microcapsules and can be dispersed in water can be used. This can be rephrased as a resin coating pigment. In this case, it is not necessary that all the pigments to be blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effects of the present invention are not impaired. You may be.
Examples of the method of dispersing using a dispersant include a known low-molecular-weight dispersant represented by a surfactant and a method of dispersing using a high-molecular-weight dispersant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and a naphthalene sulfonate Na formalin condensate can also be suitably used as a dispersant.
The dispersant may be used alone or in combination of two or more.

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

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

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

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

<About solid content>
The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose, but from the viewpoint of improving image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number of inks. Is preferably 20 nm or more and 1000 nm or less, and more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

<Additives>
If necessary, an antifoaming agent, an antiseptic antifungal agent, a rust preventive agent, a pH adjusting agent and the like may be added to the ink.

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

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

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

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

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

<Ink ejection head>
The ink ejection head has a nozzle plate and, if necessary, other members.

<< Nozzle plate >>
The nozzle plate has a nozzle substrate and an ink-repellent film on the nozzle substrate.

-Nozzle board-
The nozzle substrate is provided with nozzle holes, and the number, shape, size, material, structure, and the like are not particularly limited and can be appropriately selected depending on the intended purpose.
The nozzle substrate has an ink ejection side surface on which ink is ejected from the nozzle hole, and a liquid chamber joint surface located on the side opposite to the ink ejection side surface.
The ink-repellent film is formed on the surface of the nozzle substrate on the ink ejection side.

The planar shape of the nozzle substrate is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a rectangle, a square, a rhombus, a circle, and an ellipse. Further, examples of the cross-sectional shape of the nozzle substrate include a flat plate shape and a plate shape.
The size of the nozzle substrate is not particularly limited and may be appropriately selected depending on the size of the nozzle plate.

The material of the nozzle substrate is not particularly limited and may be appropriately selected depending on the intended purpose. For example, stainless steel, Al, Bi, Cr, InSn, ITO, Nb, Nb ₂ O ₅ , NiCr, Si, etc. Examples thereof include SiO ₂ , Sn, Ta ₂ O ₅ , Ti, W, ZAO (ZnO + Al ₂ O ₃ ), and Zn. These may be used alone or in combination of two or more. Among these, stainless steel is preferable from the viewpoint of rust prevention.

The stainless steel is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include austenitic stainless steel, ferritic stainless steel, martensitic stainless steel and precipitation hardening stainless steel. These may be used alone or in combination of two or more.

A hydroxyl group may be introduced by performing oxygen plasma treatment on at least the surface of the nozzle substrate on the ink ejection side from the viewpoint of improving the adhesion between the ink-repellent film and the nozzle substrate.

-Nozzle hole-
The number, arrangement, spacing, opening shape, opening size, cross-sectional shape of the opening, and the like are not particularly limited as the nozzle holes, and can be appropriately selected depending on the intended purpose.
The arrangement of the nozzle holes is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a plurality of the nozzle holes are arranged at equal intervals along the length direction of the nozzle substrate. And the like.
The arrangement of the nozzle holes can be appropriately selected according to the type of ink to be ejected, but one row to a plurality of rows is preferable, and one row to four rows are more preferable.
The number of the nozzle holes per row is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 or more and 10,000 or less, and more preferably 50 or more and 500 or less.
The interval (pitch) P, which is the shortest distance between the centers of the adjacent nozzle holes, is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 μm or more and 169 μm or less, for example.
The opening shape of the nozzle hole is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a circular shape, an elliptical shape, and a quadrangular shape. Among these, a circular shape is preferable from the viewpoint of ejecting ink droplets.

-Ink repellent film-
The ink-repellent film preferably contains a silicone resin or a fluororesin from the viewpoint of ink repellency.
The ink-repellent film may also be referred to as an ink-repellent material-containing film, a polymer-containing film, a silicone resin-containing film, a fluororesin-containing film, or the like.

--Silicone resin ---
The silicone resin is a resin having a siloxane bond made of Si and O as a basic skeleton, and is commercially available in various forms such as oil, resin, and elastomer, and has heat resistance in addition to the ink repellency important in the present invention. It has various properties such as property, mold release property, defoaming property, and adhesiveness. Silicone resins include room temperature curing, heat curing, ultraviolet curing type, etc., and can be selected according to the manufacturing method and intended use.
Examples of the method of forming the ink-repellent film containing the silicone resin on the nozzle surface include a method of vacuum-depositing a liquid silicone resin material, a method of forming a silicone oil by plasma polymerization, spin coating, dipping, and spraying. Examples thereof include a method of forming by applying a coat and the like, an electrodeposition method and the like. When forming the ink-repellent layer, except for the electrodeposition method, the nozzle hole and the back surface of the nozzle plate are masked with a photoresist, a water-soluble resin, etc., and after the ink-repellent layer is formed, the resist is peeled off and removed to obtain only the nozzle plate surface. In addition, an ink-repellent layer containing a silicone resin can be formed. In this case, care must be taken because using a highly alkaline stripping solution will damage the ink-repellent layer.
The thickness of the ink-repellent film containing the silicone resin is preferably 0.1 μm or more and 5.0 μm or less, and more preferably 0.1 μm or more and 1.0 μm or less.

--Fluororesin ---
As the fluororesin, a fluorine-containing acrylate ester polymer or a polymer having a fluorine-containing heterocyclic structure in the main chain is preferable.
When the ink-repellent film contains the fluorine-containing acrylate ester polymer or a polymer having a fluorine-containing heterocyclic structure in the main chain, the surface free energy becomes very small, and the ink having a low surface tension used in the present invention. Even if it is, it is preferable because it can maintain a state in which it is difficult to get wet.

The fluorine content in the fluorine-containing acrylate ester polymer is preferably 10% by mass or more, more preferably 25% by mass or more, still more preferably 50% by mass or more, from the viewpoint of ink repellency (contact angle).

As the fluorine-containing acrylate ester polymer, a polymer synthesized as appropriate may be used, or a commercially available product may be used.
Examples of the commercially available products include krytoxFSL (manufactured by DuPont), krytoxFSH (manufactured by DuPont), FomblinZ (manufactured by Solbeisolexis), FLUOROLINKS10 (manufactured by Solbeisolexis), Optool DSX (manufactured by Daikin Industries, Ltd.). FLUOROLINKC10 (manufactured by Solbeisolexis), Morescophosphalol A20H (manufactured by Matsumura Petroleum Research Institute Co., Ltd.), Morescophosphalol ADOH (manufactured by Matsumura Petroleum Research Institute Co., Ltd.) Matsumura Petroleum Research Institute), Fluorosurf FG5010 (Fluorotechnology), Fluorosurf FG5020 (Fluorotechnology), Fluorosurf FG5060 (Fluorotechnology), Fluorosurf FG5070 (Fluorotechnology), Cytop CTX-105 (Asahi Glass) (Manufactured by Co., Ltd.), Cytop CTX-805 (manufactured by Asahi Glass Co., Ltd.), Teflon (registered trademark) AF1600, AF2400 (manufactured by DuPont) and the like.

The ink-repellent film is composed of a compound film containing the fluorine-containing acrylate ester polymer skeleton in the molecule. An inorganic oxide layer is provided between the nozzle substrate and the ink-repellent film in order to improve adhesion by allowing a large number of hydroxyl groups to be present as bonding points with compounds containing a fluorine-containing acrylate ester polymer skeleton in the molecule. You can also do it.
Examples of the material of the inorganic oxide layer include SiO ₂ and TiO ₂ .
The average thickness of the inorganic oxide layer is preferably 0.001 μm or more and 0.2 μm or less, and more preferably 0.01 μm or more and 0.1 μm or less.

Examples of the method for forming the ink-repellent film by the compound containing the fluorine-containing acrylate ester polymer skeleton in the molecule include methods such as spin coating, roll coating, application such as dipping, printing, and vacuum deposition using a fluorine solvent. Be done.
Examples of the fluorine-based solvent include Novelle (manufactured by 3M Co., Ltd.), Bartrel (manufactured by DuPont), Galden (manufactured by Solbeisolexis), and trade name: "Aflud" (trade name: manufactured by Asahi Glass Co., Ltd.) Solvent), "Fluorinert FC-75" (trade name: a liquid containing perfluoro (2-butyltetrahydrofuran) manufactured by 3M) and the like.

<Other parts>
The other member is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a pressurizing chamber and a stimulus generating means.

-Pressure chamber-
The pressurizing chamber is a plurality of individual flow paths that are individually arranged corresponding to the plurality of nozzle holes provided in the nozzle plate and communicate with the nozzle holes, and are an ink flow path, a pressurized liquid chamber, and the like. It may also be called a pressure chamber, a discharge chamber, a liquid chamber, or the like.

-Stimulation generating means-
The stimulus generating means is a means for generating a stimulus applied to the ink.
The stimulus in the stimulus generating means is not particularly limited and may be appropriately selected depending on the intended purpose, and examples thereof include heat (temperature), pressure, vibration, and light. These may be used alone or in combination of two or more. Among these, heat and pressure are preferably mentioned.
Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generator, an ultrasonic oscillator, and a light. Specifically, as the stimulus generating means, a piezoelectric actuator such as a piezoelectric element, a thermal actuator using an electric heat conversion element such as a heat generating resistor to utilize a phase change due to boiling of an ink film, and a metal phase change due to a temperature change. Examples thereof include a shape memory alloy actuator using the above and an electrostatic actuator using an electrostatic force.

When the stimulus is "heat", heat energy corresponding to the recording signal is applied to the ink in the ink ejection head by using, for example, a thermal head. Examples thereof include a method in which bubbles are generated in the ink by the heat energy and the ink is ejected as droplets from the nozzle holes of the nozzle plate by the pressure of the bubbles.
When the stimulus is "pressure", for example, the piezoelectric element bends by applying a voltage to the piezoelectric element adhered to a position called the pressure chamber in the ink flow path in the ink ejection head. .. As a result, the volume of the pressure chamber contracts, and the ink is ejected as droplets from the nozzle hole of the ink ejection head. Among these, the piezo method in which a voltage is applied to the piezo element to fly the ink is preferable.

Here, an example of the ink ejection head used in the present invention will be described with reference to FIGS. 3 to 5. 3 is an exploded perspective explanatory view of the ink ejection head, FIG. 4 is a cross-sectional explanatory view along a direction (longitudinal direction of the liquid chamber) orthogonal to the nozzle arrangement direction of the ink ejection head, and FIG. 5 is a nozzle arrangement direction of the ink ejection head. It is sectional drawing which follows (the short side direction of a liquid chamber).

The ink ejection head is a flow path plate (liquid chamber substrate, flow path member) 1, a diaphragm member 2 joined to the lower surface of the flow path plate 1, and a nozzle forming member joined to the upper surface of the flow path plate 1. A plurality of liquid chambers (pressurized liquid chambers) as individual flow paths having a certain nozzle plate 3 and having a plurality of nozzle holes 4 for ejecting droplets (ink droplets) communicating with each other through a communication passage 5. (Also referred to as a pressure chamber, a pressurizing chamber, a flow path, etc.) 6, a fluid resistance portion 7 that also serves as a supply path for supplying ink to the liquid chamber 6, and communicating with the liquid chamber 6 via the fluid resistance portion 7. The communication portion 8 is formed, and the ink is supplied to the communication portion 8 from the common liquid chamber 10 formed in the frame member 17 through the supply port 19 formed in the diaphragm member 2.

The flow path plate 1 is formed by etching a silicone substrate to form openings such as a communication passage 5, a pressurized liquid chamber 6, and a fluid resistance portion 7. The flow path plate 1 can also be formed, for example, by etching a SUS substrate with an acidic etching solution or by machining such as punching (pressing).

The diaphragm member 2 has each vibration region (diaphragm portion) 2a forming a wall surface corresponding to each liquid chamber 6, and an island-shaped convex portion on the outside surface (opposite surface side of the liquid chamber 6) of the vibration region 2a. 2b is provided, and the vibration regions 2a are deformed in the island-shaped convex portion 2b, and the piezoelectric elements 12 and 12 of the laminated piezoelectric elements 12 and 12 are used as drive elements (actuator means, pressure generating means) to generate energy for discharging droplets. The upper end surface (joining surface) of the element column 12A is joined. Further, the lower end surface of the laminated piezoelectric element 12 is joined to the base member 13.

Here, the piezoelectric element 12 is formed by alternately laminating a piezoelectric material layer 21 such as PZT and internal electrodes 22a and 22b, and the internal electrodes 22a and 22b are respectively attached to the end face, that is, the vibrating plate member 2 of the piezoelectric element 12. It is pulled out to a substantially vertical side surface, connected to the end face electrodes (external electrodes) 23a and 23b formed on this side surface, and a voltage is applied to the end face electrodes (external electrodes) 23a and 23b to cause displacement in the stacking direction. The piezoelectric element 12 is grooved by half-cut dying to form a required number of piezoelectric element columns 12A and 12B for one piezoelectric element member.

The piezoelectric element columns 12A and 12B of the piezoelectric element 12 are the same, but the piezoelectric element columns that are driven by giving a drive waveform are used as the piezoelectric element columns 12A and the piezoelectric element columns that are simply used as columns without giving a drive waveform. Is distinguished as the piezoelectric element column 12B. In this case, either a bi-pitch configuration in which the drive piezoelectric element columns 12A and the support piezoelectric element columns 12B are used alternately, or a normal pitch configuration in which all the piezoelectric element columns are used as the drive piezoelectric element columns 12A are adopted. it can.

As a result, two rows of drive element rows (rows of drive piezoelectric element pillars 12A) in which a plurality of drive piezoelectric element pillars 12A as drive elements are arranged side by side are provided on the base member 13.

Further, the ink in the liquid chamber 6 is pressurized by using the displacement in the d33 direction as the piezoelectric direction of the laminated piezoelectric element 12, but the pressurized liquid is pressurized by using the displacement in the d31 direction as the piezoelectric direction of the laminated piezoelectric element 12. It is also possible to pressurize the ink in the chamber 6.

Further, the piezoelectric element material is not particularly limited, and an electromechanical conversion element such as a ferroelectric substance such as Badio ₃ , PbTIO ₃ , (NK) NbO ₃ , which is generally used as a piezoelectric element material, can also be used. Further, although a laminated type piezoelectric element is used, a single plate piezoelectric element may be used. The piezoelectric element of the single plate may be a machined one, a thick film obtained by screen printing and sintering, or a thin film formed by sputtering, vapor deposition, or a sol-gel method. Further, the laminated piezoelectric elements 12 provided in one base member 13 may be provided in one row or in a plurality of rows.

Then, an FPC 15 as a wiring means is directly connected to the external electrode 23a of each drive piezoelectric element column 12A of the piezoelectric element 12 with a solder member in order to give a drive signal, and each drive piezoelectric of the piezoelectric element 12 is directly connected to the FPC 15. A drive circuit (driver IC) 16 for selectively applying a drive waveform to the element column 12A is mounted. The external electrodes 23b of all the piezoelectric element columns 12A are electrically and commonly connected, and are also connected to the common wiring of the FPC 15 by a solder member. Further, here, the output terminal portion to be bonded to the piezoelectric element 12 of the FPC 15 is solder-plated to enable solder bonding, but even if the piezoelectric element 12 side is solder-plated instead of the FPC 15. Good. In addition to solder bonding, bonding with an anisotropic conductive film or wire bonding can also be used as the bonding method.

The nozzle plate 3 is a droplet ejection side surface (surface in the ejection direction: ejection surface or liquid) of a nozzle substrate 31 in which a hole portion forming a nozzle hole 4 having a diameter of 10 μm or more and 35 μm or less is formed corresponding to each liquid chamber 6. The ink-repellent film 32 is formed on the surface opposite to the chamber 6 side, the nozzle forming surface).

Further, on the outer peripheral side of the piezoelectric actuator unit 100 composed of the piezoelectric element 12 on which the FPC 15 is mounted (connected) and the base member 13, a frame member 17 formed by injection molding with an epoxy resin or polyphenylene sulfide is formed. It is joined. Then, the above-mentioned common liquid chamber 10 is formed in the frame member 17, and a supply port 19 for supplying ink from the outside is further formed in the common liquid chamber 10, and the supply port 19 is further not shown for a sub tank or ink. Connected to an ink source such as a containment container.

In the ink ejection head configured in this way, for example, by lowering the voltage applied to the piezoelectric element column 12A from the reference potential, the piezoelectric element column 12A contracts, and the vibration region 2a of the vibrating plate member 2 descends to form a liquid chamber. As the volume of 6 expands, ink flows into the liquid chamber 6, and then the voltage applied to the piezoelectric element column 12A is increased to extend the piezoelectric element column 12A in the stacking direction, and the vibrating plate member 2 is inserted into the nozzle hole. By deforming in four directions and contracting the volume / volume of the liquid chamber 6, the ink in the liquid chamber 6 is pressurized, and droplets of ink are ejected (jetted) from the nozzle hole 4.

Then, by returning the voltage applied to the piezoelectric element column 12A to the reference potential, the diaphragm member 2 is restored to the initial position, the liquid chamber 6 expands and a negative pressure is generated. Therefore, at this time, the common liquid chamber 10 is used. The liquid chamber 6 is filled with ink. Therefore, after the vibration of the meniscus surface of the nozzle hole 4 is attenuated and stabilized, the operation for the next droplet ejection is started.

The method of driving the ink ejection head is not limited to the above example (pull-pushing), and pulling or pushing may be performed depending on the driving waveform.

(recoding media)
The recording medium is not particularly limited, and examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper.

The recording medium is not particularly limited, and plain paper, glossy paper, special paper, cloth, or the like can be used, but good image formation is possible even if a non-permeable base material is used.
The non-permeable base material is a base material having a surface having low water permeability and low absorbability, and includes a material that does not open to the outside even if there are many cavities inside, and more quantitatively. , A base material having a water absorption amount of 10 mL / m ² or less from the start of contact to 30 msec ^1/2 in the Bristow method.
As the impermeable substrate, for example, a plastic film such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, polypropylene, polyethylene, or a polycarbonate film can be preferably used.

<Recorded material>
The ink recording material of the present invention comprises an image formed by using the ink of the present invention on a recording medium.
It can be recorded by an inkjet recording device and an inkjet recording method to obtain a recorded material.

(Recording device, recording method)
The ink used in the present invention can be suitably used for various recording devices by an inkjet recording method, for example, a printer, a facsimile device, a copying device, a printer / fax / copier multifunction device, a three-dimensional modeling device, and the like.
In the present invention, the recording device and the recording method are devices capable of ejecting ink, various processing liquids, and the like to a recording medium, and a method of recording using the device. The recording medium means a medium to which ink and various treatment liquids can adhere even temporarily.
This recording device can include not only a head portion for ejecting ink, but also means related to feeding, transporting, and discharging paper of a recording medium, and other devices called pretreatment devices and posttreatment devices. ..
The recording device and recording method may include a heating means used in the heating step and a drying means used in the drying step. The heating means and the drying means include, for example, means for heating and drying the print surface and the back surface of the recording medium. The heating means and the drying means are not particularly limited, but for example, a hot 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 device and the recording method are not limited to those in which significant images such as characters and figures are visualized by ink. For example, those that form patterns such as geometric patterns and those that form a three-dimensional image are also included.
Further, the recording device includes both a serial type device that moves the discharge head and a line type device that does not move the discharge head, unless otherwise specified.
Further, as this recording device, not only a desktop type but also a wide recording device capable of printing on an A0 size recording medium, or, for example, continuous paper wound in a roll shape can be used as a recording medium. Also included are possible continuous line printers.

An example of the recording device will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective explanatory view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanical unit 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink container 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is, for example, an aluminum laminate film or the like. It is made of packaging members. The ink container 411 is housed 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 behind the opening when the cover 401c of the main body of the apparatus is opened. A main tank 410 is detachably attached to the cartridge holder 404. As a result, each ink discharge port 413 of the main tank 410 and the discharge head 434 for each color communicate with each other via the supply tube 436 for each color, and ink can be discharged from the discharge head 434 to the recording medium.

The method of using the ink is not limited to the inkjet recording method, and can be widely used. In addition to the inkjet recording method, examples thereof include a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, and a spray coating method.

The use of the ink used in the present invention is not particularly limited and can be appropriately selected depending on the intended purpose. For example, it can be applied to printed matter, paints, coating materials, base materials and the like. Further, it can be used not only as an ink to form two-dimensional characters and images, but also as a material for three-dimensional modeling for forming a three-dimensional three-dimensional image (three-dimensional model).
A known three-dimensional modeling device can be used for modeling the three-dimensional object, and the device is not particularly limited, but for example, an device provided with ink accommodating means, supply means, ejection means, drying means, and the like is used. be able to. The three-dimensional model includes a three-dimensional model obtained by overcoating with ink. In addition, a molded product obtained by processing a structure in which ink is applied on a base material such as a recording medium is also included. The molded product is, for example, a recorded material or structure formed in the form of a sheet or a film, which has been subjected to molding processing such as heat stretching or punching. For example, an automobile, an OA device, or electricity. -Suitably used for molding after decorating the surface of electronic devices, meters of cameras, panels of operation parts, etc.

In addition, image formation, recording, printing, printing, etc. in the terms of the present invention are all synonymous terms.
Recording media, media, and printed matter are all synonymous.

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

(Preparation Example 1 of Pigment Dispersion)
<Preparation of cyan pigment dispersion>
SENSIJET SMART Cyan 3154BA (Pigment Blue 15: 4 surface treatment dispersion, pigment solid content 14.5% by mass, manufactured by SENSIENT) 1 kg of pigment dispersion was acidified with a 0.1 N HCl aqueous solution. Then, the pH was adjusted to 9 with a 40 mass% benzyltrimethylammonium hydroxide solution (methanol solution) to obtain a modified pigment dispersion after 30 minutes.
Next, ultrafiltration using a dialysis membrane was performed using a modified pigment dispersion containing a pigment bonded to at least one aminobenzoic acid group or a benzyltrimethylammonium salt of aminobenzoate obtained and ion-exchanged high pure water. ..
Further, ultrasonic dispersion was performed to obtain a cyan pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
The volume average particle size of the obtained cyan pigment dispersion was measured by a particle size distribution measuring device (Nanotrack UPA-EX150, manufactured by Nikkiso Co., Ltd.) and found to be 116 nm.

(Preparation Example 2 of Pigment Dispersion)
<Preparation of black pigment dispersion>
100 g of Black Pearls® (registered trademark) 1000 (carbon black having a BET specific surface area of 343 m ² / g and DBPA 105 mL / 100 g) manufactured by Cabot Corporation, 100 mmol of sulfanilic acid, and 1 L of ion-exchanged high pure water in a Silverson mixer at room temperature. Mix at (6,000 rpm).
If the pH of the resulting slurry was higher than 4, 100 mmol of nitric acid was added. After 30 minutes, sodium nitrite (100 mmol) dissolved in a small amount of ion-exchanged hyperpure water was slowly added to the mixture. Further, the mixture was heated to 60 ° C. with stirring and reacted for 1 hour. A modified pigment in which sulfanilic acid was added to carbon black could be produced. Next, the pH was adjusted to 9 with a 10 mass% tetrabutylammonium hydroxide solution (methanol solution) to obtain a modified pigment dispersion after 30 minutes.
Next, ultrafiltration using a dialysis membrane was performed using a modified pigment dispersion bonded to at least one obtained sulfanilic acid group or a tetrabutylammonium sulfanilic acid salt and ion-exchanged high pure water.
Further, ultrasonic dispersion was performed to obtain a black pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
The surface treatment level of the obtained black pigment dispersion was 0.75 mmol / g, and the volume average particle size was 120 nm as measured by a particle size distribution measuring device (Nanotrack UPA-EX150, manufactured by Nikkiso Co., Ltd.). ..

(Preparation Example 3 of Pigment Dispersion)
<Preparation of magenta pigment dispersion>
SENSIJET SMART Magenta 3122BA (Pigment Red 122 surface treatment dispersion, pigment solid content 14.5% by mass, manufactured by SENSIENT) 1 kg of pigment dispersion was acidified with a 0.1 N HCl aqueous solution.
Then, the pH was adjusted to 9 with a 10 mass% tetraethylammonium hydroxide aqueous solution to obtain a modified pigment dispersion after 30 minutes.
Next, ultrafiltration using a dialysis membrane was performed using a modified pigment dispersion containing a pigment bonded to at least one aminobenzoic acid group or tetraethylammonium aminobenzoate salt obtained and ion-exchanged high pure water. Ultrasonic dispersion was performed to obtain a magenta pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
The volume average particle size of the obtained magenta pigment dispersion was measured by a particle size distribution measuring device (Nanotrack UPA-EX150, manufactured by Nikkiso Co., Ltd.) and found to be 104 nm.

(Preparation Example 4 of Pigment Dispersion)
<Preparation of yellow pigment dispersion>
30 by adjusting the pH to 9 with a 10% by mass tetrabutylammonium hydroxide solution (methanol solution) of SENSIJET SMART Yellow 3074BA (Pigment Yellow 74 surface-treated dispersion, pigment solid content 14.5% by mass, manufactured by SENSIENT). After a minute, a modified pigment dispersion was obtained.
Next, ultrafiltration using a dialysis membrane was performed using a modified pigment dispersion containing a pigment bonded to at least one aminobenzoic acid group or tetrabutylammonium aminobenzoate salt obtained and ion-exchanged high pure water. Further, ultrasonic dispersion was performed to obtain a yellow pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
The volume average particle size of the obtained yellow pigment dispersion was measured by a particle size distribution measuring device (Nanotrack UPA-EX150, manufactured by Nikkiso Co., Ltd.) and found to be 145 nm.

(Ink Preparation Example 1)
<Making ink>
Inks were prepared with the compositions and contents shown in Tables 1 and 2 below as follows.
An organic solvent, a compound represented by the above general formula (1), a surfactant, and an antifoaming agent were mixed in a container equipped with a stirrer, and stirred for 30 minutes to make them uniform.
Next, the fungicide, the pH adjuster, and the colorant were mixed and stirred, and if necessary, the resin was mixed and stirred to make the ink uniform.
The obtained ink was pressure-filtered with a polyvinylidene fluoride membrane filter having an average pore size of 1.2 μm to remove coarse particles and dust to prepare inks 1 to 24.

The abbreviations in Tables 1 and 2 have the following meanings.
* Movinyl 6969D: Styrene-acrylic resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
* W6110: Urethane resin (manufactured by Mitsui Chemicals, Inc.)
* TRITON HW-1000: Compound represented by the above general formula (1), n = 6 (average) (manufactured by Dow Chemical Co., Ltd.)
* TERGITOR TMN-3: Compound represented by the above general formula (1), n = 3 (average) (manufactured by Dow Chemical Co., Ltd.)
* TERGITOR TMN-6: Compound represented by the above general formula (1), n = 8 (average) (manufactured by Dow Chemical Co., Ltd.)
* TERGITOR TMN-10: Compound represented by the above general formula (1), n = 11 (average) (manufactured by Dow Chemical Co., Ltd.)
* TEGO Wet270: Polyester-modified siloxane compound (manufactured by Evonik Degussa Japan, 100% by mass of active ingredient)
* Unidyne DSN403N: Polyoxyethylene perfluoroalkyl ether (manufactured by Daikin Industries, Ltd., 100% by mass of active ingredient)
* Softanol EP-7025: Higher alcohol ethoxylate compound (manufactured by Nippon Shokubai Co., Ltd., 100% by mass of active ingredient)
* Surfinol 104E: Acetylene glycol compound (manufactured by Nissin Chemical Industry Co., Ltd., 100% by mass of active ingredient)
* Proxel LV: Antifungal agent containing 1,2-benzisothiazolin-3-one as the main component (manufactured by Lonza, 20% by mass of component, containing dipropylene glycol)

(Production example 1 of nozzle plate)
<Making the nozzle plate 1>
A nozzle substrate made of stainless steel (SUS304) having a length of 34 mm, a width of 16 mm, and an average thickness of 20 μm was prepared. The nozzle substrate is formed with four rows of nozzle holes arranged in 320 pieces / row with a pitch of 85 μm (300 dpi), which is the shortest distance between the centers of the nozzle holes having an average hole diameter of 25 μm. ing.
A fluorine-containing acrylate ester polymer solution (Optur DSX, manufactured by Daikin Industries, Ltd.) is applied to the surface of the nozzle substrate on the ink ejection side by a dipping method and dried to form an ink-repellent film having an average thickness of 20 nm. Formed. At this time, the nozzle holes were masked with a water-soluble resin, and the back surface of the nozzle substrate was masked with tape to form an ink-repellent film, which was then peeled off. Further, the ink-repellent film was formed by heating at 120 ° C. for 1 hour.
From the above, the nozzle plate 1 was manufactured.

(Production example 2 of nozzle plate)
<Making the nozzle plate 2>
In Manufacturing Example 1 of the nozzle plate, a silicone resin solution (SR 2441 RESIN, manufactured by Toray Dow Corning Co., Ltd.) is applied to the ink ejection side surface of the same nozzle substrate as the nozzle plate 1 by a dipping method, and dried. , An ink-repellent film having an average thickness of 100 nm was formed. At this time, the nozzle holes were masked with a water-soluble resin, and the back surface of the nozzle substrate was masked with tape to form an ink-repellent film, which was then peeled off. This was heat-cured at 150 ° C. for 2 hours in the air to obtain an ink-repellent film.
From the above, the nozzle plate 2 was manufactured.

Next, using the combination of the ink and the nozzle plate shown in Table 3, various characteristics were evaluated as follows. The results are shown in Table 3.

<Backward contact angle with respect to nozzle plate>
The following evaluations were performed to evaluate the ease with which the ink spreads on the nozzle plate.
Under environmental conditions adjusted to 25 ° C and 50% ± 5% RH, 2.5 μL of each ink was extruded into each nozzle plate from a syringe equipped with a syringe needle with an inner diameter of 0.37 μm, and retracted at 25 ° C by the shrinkage method. The contact angle (°) was measured by an automatic contact angle measuring device (DSA25, manufactured by KRUSS).

<Evaluation of beading>
The following evaluations were performed to evaluate the density unevenness (beading) of the solid image of the printed matter.
Using an image forming device (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) under environmental conditions adjusted to 23 ° C ± 1 ° C and 50% ± 5% RH, drive the piezo element so that the ink ejection amount is even. Ink was ejected to a recording medium (OK top coat +, basis weight: 127.9 g / m ² , manufactured by Oji Paper Co., Ltd.) by varying the voltage to obtain a print sample. As the print chart, a solid image of 3 cm square formed by a dot pattern was used.
Next, the obtained print sample was visually observed, and the density unevenness (beading) of the solid image was evaluated based on the following evaluation criteria. In addition, B or higher is a level that can be actually used.
[Evaluation criteria]
A: No density unevenness B: Slight density unevenness C: Significant density unevenness D: Severe density unevenness

<Intermittent discharge stability>
The following evaluations were performed to evaluate the ejection stability during printing.
Using an image forming device (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) under environmental conditions adjusted to 23 ° C ± 1 ° C and 50% ± 5% RH, a continuous chart is used to fill 45 cm x 70 cm per color with a solid image. 200 sheets were printed, and evaluation was performed based on the following evaluation criteria based on the ejection turbulence of each nozzle after printing. In addition, B or higher is a level that can be actually used.
[Evaluation criteria]
A: No discharge turbulence B: Some discharge turbulence C: Discharge turbulence D: Discharge turbulence or part not discharged

<Discharge stability after decap>
The following evaluations were performed to evaluate the discharge stability after leaving the decap.
The following operations were performed under environmental conditions adjusted to 23 ° C. ± 1 ° C. and 50% ± 5% RH.
First, fill each ink, use an image forming device (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) equipped with each nozzle plate, execute head cleaning from a maintenance command, print a test chart, and print all nozzle channels. Was confirmed to be in the discharge state.
Next, after leaving the head cap removed for 120 minutes, the test chart was printed again. The number of non-ejection channels was counted from the test chart before and after leaving, and the judgment was made according to the following criteria. In addition, B or higher is a level that can be actually used.
[Evaluation criteria]
A: Number of non-discharge channels is 1 or less B: Number of non-discharge channels is 2 or more and less than 10 C: Number of non-discharge channels is 10 or more

* 1: Higher alcohol ethoxylate surfactant * 2: Acetylene glycol surfactant

Examples of aspects of the present invention are as follows.
<1> An ink ejection head having a nozzle plate having an ink-repellent film and
An ink containing a compound represented by the following general formula (1), a coloring material, and a surfactant having a material different from that of the ink-repellent film.
It is an image forming apparatus characterized by having.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.
<2> The image forming apparatus according to <1>, wherein the material different from the ink-repellent film is an element different from the element that causes the ink-repellent property of the ink-repellent film.
<3> When the ink-repellent film contains a fluorine element, the surfactant has a silicon element.
The image forming apparatus according to any one of <1> to <2>, wherein when the ink-repellent film contains a silicon element, the surfactant has a fluorine element.
<4> The image forming apparatus according to any one of <1> to <3>, wherein the receding contact angle of the ink with respect to the nozzle plate is 35 ° or more.
<5> The compound represented by the general formula (1) is the image forming apparatus according to any one of <1> to <4>, wherein n is 3 to 8 on average.
<6> The compound represented by the general formula (1) is the image forming apparatus according to any one of <1> to <5>, wherein n is 6 on average.
<7> For a recording medium, from an ink ejection head provided with a nozzle plate having an ink-repellent film, a compound represented by the following general formula (1), a coloring material, and a surface activity having a material different from the ink-repellent film. An image forming method comprising an ink ejection step of ejecting ink containing an agent.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.
<8> The image forming method according to <7>, wherein the material different from the ink-repellent film is an element different from the element that causes the ink-repellent property of the ink-repellent film.
<9> When the ink-repellent film contains a fluorine element, the surfactant has a silicon element.
The image forming method according to any one of <7> to <8>, wherein when the ink-repellent film contains a silicon element, the surfactant has a fluorine element.
<10> The image forming method according to any one of <7> to <9>, wherein the receding contact angle of the ink with respect to the nozzle plate is 35 ° or more.
<11> The compound represented by the general formula (1) is the image forming method according to any one of <7> to <10>, wherein n is 3 to 8 on average.
<12> The compound represented by the general formula (1) is the image forming method according to any one of <7> to <11>, wherein n is 6 on average.
<13> An ink ejection head that ejects ink containing a compound, a coloring material, and a surfactant represented by the following general formula (1).
The ink ejection head has a nozzle plate having an ink-repellent film, and the ink-repellent film has a material different from that of the surfactant.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.
<14> An ink ejection head having a nozzle plate having an ink-repellent film and
An ink containing a compound represented by the following general formula (1), a coloring material, and a surfactant,
Have,
When the ink-repellent film contains a fluorine element, the surfactant has a silicon element.
The image forming apparatus is characterized in that when the ink-repellent film contains a silicon element, the surfactant has a fluorine element.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.
<15> An ink ejection head having a nozzle plate having an ink-repellent film and
Inks containing compounds, coloring materials, and liquid components represented by the following general formula (1), and
Have,
When the ink-repellent film contains a fluorine element, the liquid component contains a compound having a silicon element.
The image forming apparatus is characterized in that when the ink-repellent film contains a silicon element, the liquid component contains a compound having a fluorine element.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.
<16> An ink used in an image forming apparatus having an ink ejection head having a nozzle plate having an ink-repellent film.
The ink is an ink characterized by containing a compound represented by the following general formula (1), a coloring material, and a surfactant having a material different from that of the ink-repellent film.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.
<17> An ink used in an image forming apparatus having an ink ejection head having a nozzle plate having an ink-repellent film.
The ink contains a compound represented by the following general formula (1), a coloring material, and a surfactant.
When the ink-repellent film contains a fluorine element, the surfactant has a silicon element.
When the ink-repellent film contains a silicon element, the surfactant is an ink characterized by having a fluorine element.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.
<18> The ink according to any one of <16> to <17>, wherein the material different from the ink-repellent film is an element different from the element that causes the ink-repellent property of the ink-repellent film.
<19> When the ink-repellent film contains a fluorine element, the surfactant has a silicon element.
When the ink-repellent film contains a silicon element, the ink according to any one of <16> to <18>, wherein the surfactant has a fluorine element.
<20> The ink according to any one of <16> to <19>, wherein the receding contact angle of the ink with respect to the nozzle plate is 35 ° or more.
<21> The compound represented by the general formula (1) is the ink according to any one of <16> to <20>, wherein n is 3 to 8 on average.
<22> The compound represented by the general formula (1) is the ink according to any one of <16> to <21>, wherein n is 6 on average.

The image forming apparatus according to any one of <1> to <6> and <14> to <15>, the image forming method according to any one of <7> to <12>, and the above <13>. According to the above-described ink ejection head and the ink according to any one of <16> to <22>, it is possible to solve various conventional problems and achieve the object of the present invention.

400 Image forming device 401 Image forming device exterior 401c Device body cover 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 unit 413 Ink discharge port 414 Storage container case 420 Mechanical unit 434 Discharge head 436 Supply tube

Japanese Unexamined Patent Publication No. 2016-216701

Claims (12)

An ink ejection head having a nozzle plate with an ink repellent film,
An ink containing a compound represented by the following general formula (1), a coloring material, and a surfactant having a material different from that of the ink-repellent film.
An image forming apparatus characterized by having.
However, in the general formula (1), n is an average value and is an integer of 2 to 40. The image forming apparatus according to claim 1, wherein the material different from the ink-repellent film is an element different from the element that causes the ink-repellent property of the ink-repellent film. When the ink-repellent film contains a fluorine element, the surfactant has a silicon element.
The image forming apparatus according to any one of claims 1 to 2, wherein when the ink-repellent film contains a silicon element, the surfactant has a fluorine element. The image forming apparatus according to any one of claims 1 to 3, wherein the receding contact angle of the ink with respect to the nozzle plate is 35 ° or more. The image forming apparatus according to any one of claims 1 to 4, wherein the compound represented by the general formula (1) has an average value of 3 to 8. The image forming apparatus according to any one of claims 1 to 5, wherein the compound represented by the general formula (1) has an average value of 6. The recording medium contains a compound represented by the following general formula (1), a coloring material, and a surfactant having a material different from the ink-repellent film from an ink ejection head provided with a nozzle plate having an ink-repellent film. An image forming method comprising an ink ejection step of ejecting ink.
However, in the general formula (1), n is an average value and is an integer of 2 to 40. An ink ejection head that ejects ink containing a compound, a coloring material, and a surfactant represented by the following general formula (1).
An ink ejection head having a nozzle plate having an ink-repellent film, wherein the ink-repellent film has a material different from that of the surfactant.
However, in the general formula (1), n is an average value and is an integer of 2 to 40. An ink ejection head having a nozzle plate with an ink repellent film,
An ink containing a compound represented by the following general formula (1), a coloring material, and a surfactant,
Have,
When the ink-repellent film contains a fluorine element, the surfactant has a silicon element.
An image forming apparatus, wherein when the ink-repellent film contains a silicon element, the surfactant has a fluorine element.
However, in the general formula (1), n is an average value and is an integer of 2 to 40. An ink ejection head having a nozzle plate with an ink repellent film,
Inks containing compounds, coloring materials, and liquid components represented by the following general formula (1), and
Have,
When the ink-repellent film contains a fluorine element, the liquid component contains a compound having a silicon element.
An image forming apparatus, wherein when the ink-repellent film contains a silicon element, the liquid component contains a compound having a fluorine element.
However, in the general formula (1), n is an average value and is an integer of 2 to 40. An ink used in an image forming apparatus having an ink ejection head having a nozzle plate having an ink-repellent film.
The ink is an ink characterized by containing a compound represented by the following general formula (1), a coloring material, and a surfactant having a material different from that of the ink-repellent film.
However, in the general formula (1), n is an average value and is an integer of 2 to 40. An ink used in an image forming apparatus having an ink ejection head having a nozzle plate having an ink-repellent film.
The ink contains a compound represented by the following general formula (1), a coloring material, and a surfactant.
When the ink-repellent film contains a fluorine element, the surfactant has a silicon element.
An ink characterized in that when the ink-repellent film contains a silicon element, the surfactant has a fluorine element.
However, in the general formula (1), n is an average value and is an integer of 2 to 40.