JP2020023168A - Image formation method, image formation apparatus and image formed matter - Google Patents

Abstract

To provide an image formation method which has excellent discharge stability and makes it possible to obtain an image formed matter having adhesion, scratch resistance and chemical resistance.SOLUTION: An image formation method includes a discharge step of discharging on a recording medium an ink containing a crosslinking agent reactable with acid group, and resin having acid group. The recording medium has on a surface thereof the acid group reactable with the crosslinking agent.SELECTED DRAWING: None

Description

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

  The water-based ink used in ink-jet printing is excellent in terms of safety and environmental issues because it does not contain volatile components in the ink, but bleeds easily occur when printed on high-quality paper or plain paper. In addition, when printing is performed on the actual printing paper, drying is insufficient and high-speed printing is difficult. Further, when printing is performed on cotton or cotton blend, the ink does not stay on the fiber surface but penetrates into the inside of the fiber, and a desired image quality cannot be obtained. Further, there is a problem that printed ink cannot be fixed on a non-permeable recording medium that does not absorb ink, for example, a polymer resin film, ceramics, or a glass substrate.

  On the other hand, ultraviolet curable (UV) ink used in ink jet printing can be printed on a polymer resin film, pottery, a glass substrate, or the like, and has high followability to the substrate surface. Further, it is excellent from the viewpoint of high-speed printing because it utilizes a curing reaction by light, but has a problem in terms of safety and environment because it contains a large amount of a polymerization initiator. Further, there is a problem that the pile height of the printed coating film is high and the secondary workability of laminating or the like is poor.

In order to solve the above-described problems, various water-based UV inks have been conventionally proposed. For example, an inkjet ink containing a resin emulsion comprising a compound having a radical polymerizable group, a non-polymerizable resin emulsion, and a photo-radical polymerization initiator has been proposed (for example, see Patent Document 1).
In addition, there has been proposed an inkjet printing ink containing a water-soluble pigment dispersant having a crosslinkable functional group, a water-soluble fixing agent having a crosslinkable functional group, and a crosslinker (for example, see Patent Document 2).

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method capable of obtaining an image-formed product having excellent ejection stability and having good adhesion, scratch resistance, and chemical resistance.

  The image forming method of the present invention as a means for solving the above-mentioned problem includes a discharging step of discharging an ink containing a crosslinking agent capable of reacting with an acidic group, and a resin having an acidic group onto a recording medium, The recording medium has an acidic group capable of reacting with the crosslinking agent on the surface of the recording medium.

  According to the present invention, it is possible to provide an image forming method capable of obtaining an image-formed product having excellent ejection stability and having good adhesion, abrasion resistance and chemical resistance.

FIG. 1 is a diagram illustrating an example of an image forming apparatus that performs the image forming method of the present invention. FIG. 2 is a perspective explanatory view showing an example of a main tank of the image forming apparatus of FIG. FIG. 3 is a diagram illustrating another example of the image forming apparatus that performs the image forming method of the present invention. FIG. 4 is a plan view showing an example of the recording head of FIG.

(Image forming method and image forming apparatus)
The image forming method of the present invention includes a discharging step of discharging an ink containing a crosslinking agent capable of reacting with an acidic group and a resin having an acidic group onto a recording medium, wherein the recording medium is formed on a surface of the recording medium. It preferably has an acidic group capable of reacting with the crosslinking agent and includes a surface treatment step and an ultraviolet irradiation step, and further includes other steps as necessary.
The image forming apparatus of the present invention includes a discharging unit that discharges an ink containing a crosslinking agent capable of reacting with an acidic group and a resin having an acidic group onto a recording medium, wherein the recording medium has a surface that is a surface of the recording medium. It preferably has an acidic group capable of reacting with the crosslinking agent, and has a surface treatment means and an ultraviolet irradiation means, and further has other means as necessary.

  The image forming method of the present invention can be suitably performed by the image forming apparatus of the present invention. The discharging step can be performed by a discharging unit. The surface treatment step can be performed by the surface processing unit. Can be performed by ultraviolet irradiation means, and the other steps can be performed by other means.

In the image forming method of the present invention and the image forming apparatus of the present invention, according to the conventional technology described in Patent Document 1, as a result of a scratch resistance test on a PVC recording medium, the state of the original image could not be maintained, and the image was peeled off. This is based on the finding that the scratch resistance, adhesion and chemical resistance of the image-formed product are insufficient.
Further, the image forming method of the present invention and the image forming apparatus of the present invention, in the related art described in Patent Document 2, have an ink design on the assumption that pre-processing is performed, and perform image forming without pre-processing. It is based on the finding that the abrasion resistance, adhesion and chemical resistance of the product are not yet sufficient.

  In the present invention, the crosslinking agent capable of reacting with the acidic group contained in the ink reacted with the resin having the acidic group contained in the ink and the acidic group on the recording medium surface, respectively, and reacted with the crosslinking agent and the crosslinking agent. When the resin is bonded to the recording medium, the adhesion, scratch resistance, and chemical resistance of the image-formed product are improved without impairing the ejection stability of the ink.

<Discharge process and discharge means>
The discharging step is a step of discharging an ink containing a crosslinking agent capable of reacting with an acidic group and a resin having an acidic group onto a recording medium, and is performed by a discharging unit.

Examples of the ejection unit include an ink ejection head.
The ink ejection head ejects ink to form an image layer.
The ink ejection head has a nozzle plate, a pressure chamber, and a stimulus generation unit.

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

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

-Stimulus generation means-
The stimulus generation means is a means for generating a stimulus to be applied to the ink.
The stimulus in the stimulus generation means is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include heat (temperature), pressure, vibration, and light. These may be used alone or in combination of two or more. Among these, heat and pressure are preferred.
Examples of the stimulus generating unit include a heating device, a pressing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, and a light. As the stimulus generating means, specifically, a piezoelectric actuator such as a piezoelectric element, a thermal actuator utilizing an electrothermal conversion element such as a heating resistor and utilizing a phase change due to ink film boiling, a metal phase change due to a temperature change And an electrostatic actuator using electrostatic force.

When the stimulus is “heat”, thermal energy corresponding to a recording signal is applied to the ink in the ink ejection head using, for example, a thermal head. A method may be used in which bubbles are generated in the ink by the thermal 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 is bent by applying a voltage to the piezoelectric element bonded to a position called the pressure chamber in the ink flow path in the ink ejection head. . Thereby, there is a method in which the volume of the pressure chamber is contracted, and the ink is ejected as droplets from the nozzle holes 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.

<< Ink >>
The ink contains a crosslinking agent capable of reacting with an acidic group, and a resin having an acidic group, and further contains other components as necessary.

-Crosslinking agent capable of reacting with acidic groups-
The crosslinking agent capable of reacting with the acidic group is not particularly limited as long as it can react with the acidic group, and can be appropriately selected depending on the purpose.For example, a compound having a carbodiimide group, a compound having an isocyanate group, aziridylidine Examples of the compound include a compound having a group, a compound having a melanin group, a compound having an epoxy group, a compound having an oxazoline group, a compound having an amino group, a compound having an azo group, and a compound having a bismaleimide group. These may be used alone or in combination of two or more. Among these, a compound having a carbodiimide group and a compound having an oxazoline group are preferable from the viewpoint of adhesion, scratch resistance, and chemical resistance.
As the compound having a carbodiimide group, a compound appropriately synthesized may be used, or a commercially available product may be used. Examples of the commercially available product include carbodiimide (trade name: E-03A, manufactured by Nisshinbo Chemical Inc.).
As the compound having an oxazoline group, an appropriately synthesized compound may be used, or a commercially available product may be used. Examples of the commercially available product include oxazoline (trade name: Epocross K-2020E).

  The content of the crosslinking agent capable of reacting with the acidic group is preferably from 1% by mass to 20% by mass, more preferably from 2% by mass to 10% by mass, based on the total amount of the ink.

The crosslinking agent capable of reacting with the acidic group reacts with the resin having the acidic group and the recording medium having the acidic group on the surface of the ink by the function of the curing means.
Examples of the acidic group capable of reacting with the crosslinking agent include a carboxyl group, a phenolic hydroxyl group, an alcoholic hydroxyl group, an amine group, an amide group, an aromatic thiol group, an epoxy group, caprolactam, and an acid anhydride group. Among these, a carboxyl group or an alcoholic hydroxyl group is particularly preferred.

-Curing means-
Examples of a curing unit for curing the ink used in the present invention include a heat curing unit and a curing unit using an active energy ray.
The heat-curing means includes means for heating and drying the printing surface and the back surface of the recording medium, and includes, for example, an infrared heater, a warm air heater, and a heating roller. These may be used alone or in combination of two or more.

The method for drying the recording medium is not particularly limited and may be appropriately selected depending on the purpose. For example, a method of contacting a heated fluid such as hot air as a drying unit with the recording medium to which the ink has been applied. A method in which the recording medium to which the ink is applied is brought into contact with a heating member to heat by heat transfer, and a method in which the recording medium to which the ink is applied by irradiating energy rays such as infrared rays or far-infrared rays. .
Heating can be performed before printing, during printing, and / or after printing.
Heating before and during printing makes it possible to print on a heated recording medium, and heating after printing makes it possible to dry an image-formed product.
The drying temperature during recording is preferably 50 ° C. or higher. The upper limit of the drying temperature during recording is not particularly limited and can be appropriately selected depending on the intended purpose. However, the upper limit is preferably 120 ° C. or lower from the viewpoints of ejection reliability and thermal deformation of the substrate. Further, the temperature is more preferably 90 ° C. or less from the viewpoint of the wettability of the ink to the recording medium. The drying temperature before and after recording is not particularly limited and can be appropriately selected depending on the purpose. However, the drying temperature is preferably 100 ° C. or lower from the viewpoints of ejection reliability and thermal deformation of the recording medium.
The heating time is not particularly limited and may be appropriately selected depending on the intended purpose; however, the heating time is preferably 0.5 seconds or more and 1.5 seconds or less.
The heating time is preferably controlled by controlling the transport speed of the recording medium.

  The active energy rays used for curing the ink used in the present invention include, in addition to ultraviolet rays, electron beams, α rays, β rays, γ rays, X rays, and the like, and the polymerization reaction of a polymerizable component in the composition. What is necessary is just to be able to provide the energy required for proceeding, and there is no particular limitation. In particular, when a high energy light source is used, the polymerization reaction can proceed without using a polymerization initiator. Further, in the case of ultraviolet irradiation, mercury-free is strongly desired from the viewpoint of environmental protection, and replacement with a GaN-based semiconductor ultraviolet light emitting device is very useful industrially and environmentally. Further, an ultraviolet light emitting diode (UV-LED) and an ultraviolet laser diode (UV-LD) are small in size, have a long life, are highly efficient, and are low in cost, and are preferable as an ultraviolet light source.

-Resin having acidic group-
As the resin having an acidic group, for example, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, isocyanate, vinyl alcohol, alcohol, vinyl ether, Examples thereof include homopolymers or copolymers of vinylpyrrolidone, vinylpyridine, vinylcarbazole, vinylimidazole, and vinylidene chloride, fluororesins, and natural resins. The copolymer may be used in any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer. Further, those described in JP-B-62-1426, JP-A-3-56573, JP-A-3-79678, JP-A-3-160068, JP-A-4-18462 and the like may be used. Good. These may be used alone or in combination of two or more.
Among these, acrylic resins, styrene-acrylic resins, acrylic-silicone resins, polyurethane resins, and polyester resins are preferred.

Resin particles made of these resins may be used. Ink can be obtained by mixing resin particles with a material such as a coloring material or an organic solvent in a state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, appropriately synthesized ones or commercially available ones may be used.
The volume average particle size of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose; however, from the viewpoint of obtaining good fixability and high image hardness, it is preferably from 10 nm to 1,000 nm, and preferably from 10 nm to 1,000 nm. The thickness is more preferably from 200 nm to 200 nm, and particularly preferably from 10 nm to 100 nm.
The volume average particle size can be measured, for example, using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Inc.).

The acid value of the resin having an acidic group is preferably from 5 mgKOH / g to 100 mgKOH / mg from the viewpoint of water dispersibility, and from 5 mgKOH / g to 50 mgKOH / mg, excellent scratch resistance and excellent resistance to water. It is more preferable from the viewpoint of imparting chemical properties.
The acid value of the resin refers to the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of the resin, and is determined by an acid value measurement according to JIS K0070 and a hydrolysis acid value measurement (total acid value measurement). Can be measured.

In dispersing the resin particles in an aqueous medium, a so-called self-emulsifying type / reactive emulsifying type resin having an anionic group in a molecular structure is preferable.
Examples of the anionic group include a carboxyl group, a carboxylate group, a sulfonic acid group, and a sulfonate group. Among these, it is preferable to use a carboxylate group or a sulfonate group partially or wholly neutralized by a basic compound or the like in order to maintain good aqueous dispersion stability, and to use the anionic group in the resin. The monomer having an anionic group or the reactive surfactant may be used for the introduction.
The acidic group in the present invention includes an acidic group in equilibrium with the anionic group for dispersion.

Examples of the basic compound which can be used for neutralization of the anionic group include, for example, ammonia, triethylamine, pyridine, organic amines such as morpholine, alkanolamines such as monoethanolamine, metal bases including Na, K, Li, Ca and the like. And the like.
When the forced emulsification method is used, both a nonionic surfactant and an anionic surfactant can be used, but a nonionic surfactant is preferred because it has better water resistance.

  Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene derivative, polyoxyethylene fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester, polyoxyethylene propylene polyol, and sorbitan. Fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyalkylene polycyclic phenyl ethers, polyoxyethylene alkylamines, alkylalkanolamides, polyalkylene glycol (meth) acrylates and the like can be mentioned. These may be used alone or in combination of two or more. Among them, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene alkylamine are preferable.

Examples of the anionic surfactant include an alkyl sulfate, a polyoxyethylene alkyl ether sulfate, an alkylbenzene sulfonate, an α-olefin sulfonate, a methyl taurate, a sulfosuccinate, an ether sulfonate, and an ether carboxylic acid. Salts, fatty acid salts, naphthalenesulfonic acid formalin condensates, alkylamine salts, quaternary ammonium salts, alkylbetaines, alkylamine oxides and the like. These may be used alone or in combination of two or more. Among these, polyoxyethylene alkyl ether sulfate and sulfosuccinate are preferred.
The content of the surfactant is preferably from 0.1% by mass to 30% by mass, more preferably from 5% by mass to 20% by mass, based on the total amount of the resin. When the content of the surfactant is in the range of 0.1% by mass or more and 30% by mass or less, an ink having excellent adhesion and water resistance can be obtained, and the image formed product is good without blocking.

  Also, a method of forming by soap-free polymerization substantially using no surfactant can be suitably used, and a method of forming by soap-free polymerization is also preferable. Soap-free polymerization refers to a polymerization method for producing resin particles substantially without using a surfactant. Examples of soap-free polymerization include polymerizing polymer particles in the presence of a surfactant content of 1% by mass or less in a solution. In soap-free polymerization, for example, a (meth) acrylic acid monomer or the like can be suitably used. When polymer particles are produced using soap-free polymerization, the gloss tends to be further improved.

  Commercial products can be used as the resin having an acidic group. Examples of commercially available aqueous dispersion type polymer particles include, for example, an acrylic resin emulsion (Movinyl 7470, manufactured by Nippon Synthetic Chemical Co., Ltd.), an acrylic-silicone resin emulsion (Movinyl 7110, manufactured by Nippon Synthetic Chemical Co., Ltd.), styrene -Acrylic resin emulsion (Movinyl 972, manufactured by Nippon Synthetic Chemical Co., Ltd.).

  The content of the resin having an acidic group is not particularly limited and may be appropriately selected depending on the purpose. However, from the viewpoint of fixability and storage stability of the ink, the content is 1% by mass or more based on the total amount of the ink. 30 mass% or less is preferable, and 5 mass% or more and 20 mass% or less are more preferable.

-Photoacid generator-
The photoacid generator is a compound that generates an acid when irradiated with light. In the present invention, the photoacid generator is preferably added from the viewpoint of improving adhesion, scratch resistance and chemical resistance.
The photoacid generator is not particularly limited, and a known photoacid generator can be used. For example, “Application and market of UV / EB curing technology” (CMC Publishing, supervised by Yoneho Tabata / Radtech Research Group) Edit) etc. can be used. In the present invention, a solution in which a photoacid generator is dissolved in a polymerizable compound or a solvent may be used.
Examples of the photoacid generator include diazodisulfone-based compounds and triphenylsulfonium-based compounds.
Commercial products can be used as the photoacid generator. Examples of commercially available products include WPAG-367 (manufactured by Wako Pure Chemical Industries, Ltd.).
The content of the photoacid generator is not particularly limited and may be appropriately selected depending on the purpose. However, the content is preferably 0.1% by mass or more and 10% by mass or less based on the total amount of the ink.

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

−Water−
The content of water in the ink is not particularly limited and may be appropriately selected depending on the purpose. However, from the viewpoint of drying properties and ejection reliability of the ink, the content is preferably from 10% by mass to 90% by mass, % Or more and 60% by mass or less.

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

A polyol compound having 8 or more carbon atoms or a glycol ether compound is also preferably used.
Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Specific examples of the glycol ether compound include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;

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

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected depending on the intended purpose; however, from the viewpoint of drying properties and ejection reliability of the ink, the content is preferably from 10% by mass to 60% by mass, The content is more preferably from 20% by mass to 60% by mass.

-Coloring material-
The coloring material is not particularly limited, and pigments and dyes can be used.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Further, a mixed crystal may be used.
As the pigment, for example, black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, luster pigments such as gold and silver, and metallic pigments can be used.
As the inorganic pigment, for example, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, contact method, furnace method, manufactured by known methods such as thermal method Carbon black can be used.
Examples of the organic pigment include azo pigments and polycyclic pigments (for example, phthalocyanine pigment, perylene pigment, perinone pigment, anthraquinone pigment, quinacridone pigment, dioxazine pigment, indigo pigment, thioindigo pigment, isoindolinone pigment, quinophthalone pigment). And dye chelates (eg, basic dye chelates and acid dye chelates), nitro pigments, nitroso pigments, aniline black, and the like. Among these pigments, those having good affinity for the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can be used.
Specific examples of the pigment include carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, or copper and iron (CI pigment black 11) for black. 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 Green 1, 4, 7, 8, 10, 17, 18, 36 and the like.

The dye is not particularly limited, and an acidic dye, a direct dye, a reactive dye, and a basic dye can be used. One type of dye may be used alone, or two or more types may be used in combination.
Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive red 14, 32, 55, 79, 249, C.I. I. And reactive blacks 3, 4, and 35.

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

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

-Pigment dispersion-
It is possible to obtain an ink by mixing a material such as water or an organic solvent with a pigment. Further, it is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. The dispersion may be performed using a disperser.
There is no particular limitation on the particle size of the pigment in the pigment dispersion, but the dispersion frequency of the pigment becomes good, the ejection stability, and the image quality such as image density also become high. Is preferably 20 nm or more and 500 nm or less, more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected depending on the intended purpose; however, from the viewpoint of obtaining good ejection stability and increasing the image density, 0.1 mass % To 50% by mass, more preferably 0.1% to 30% by mass.
The pigment dispersion is preferably deaerated by filtering coarse particles of 7 μm or more with a filter, a centrifugal separator or the like, if necessary.

  The dispersed particle size (median diameter) of the solid content in the ink is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoint of improving image quality such as ejection stability and image density, the maximum is preferable. The maximum frequency in terms of the number is preferably from 20 nm to 1,000 nm, more preferably from 20 nm to 150 nm. The solid content includes resin particles and pigment particles. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Inc.).

-Surfactant-
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. Among these, those which 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 both-chain both-terminal modified polydimethylsiloxane. Those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as the group are particularly preferable because they show good properties as an aqueous surfactant.
As the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.

Examples of the fluorine-based surfactant include a perfluoroalkylsulfonic acid compound, a perfluoroalkylcarboxylic acid compound, a perfluoroalkylphosphate ester compound, a perfluoroalkylethylene oxide adduct, and a perfluoroalkylether group in a side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties.
Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid, perfluoroalkylsulfonic acid salt, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain include a sulfate salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in a side chain, and having a perfluoroalkyl ether group in a side chain. Examples include salts of polyoxyalkylene ether polymers. The counter ions of the salts in these fluorinated surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , and NH (CH ₂ CH ₂ OH) _{3 and the} like.

Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, and the like.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurylate, and polyoxyethylene alkyl ether sulfate.
These may be used alone or in combination of two or more.

The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include side-chain-modified polydimethylsiloxane, both-terminal-modified polydimethylsiloxane, one-terminal-modified polydimethylsiloxane, and a side-chain-modified polydimethylsiloxane. Both ends modified polydimethylsiloxane and the like are mentioned, and polyoxyethylene group as a modifying group, and polyether-modified silicone surfactant having a polyoxyethylene polyoxypropylene group are particularly preferable because they show good properties as an aqueous surfactant. .
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. Commercially available products are available from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Japan Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd.
The polyether-modified silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyalkylene oxide structure represented by the following general formula (S-1) may be used. Examples thereof include those introduced into the side chain of the dimethylpolysiloxane in the Si portion.
[General formula (S-1)]
(In the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R ′ represents an alkyl group.)

  Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant. -1906EX (Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK -33, BYK-387 (manufactured by Big Chemie Co., Ltd.), TSF4440, TSF4452, and TSF4453 (manufactured by Toshiba Silicon Corporation).

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

-Antifoaming agent-
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, silicone-based antifoaming agents are preferred because of their excellent foam breaking effect.

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

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

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

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

<Surface treatment step and surface treatment means>
The surface treatment step is a step of performing one of a corona discharge treatment and a plasma irradiation treatment on the recording medium before the ink lands on the recording medium, and is performed by a surface treatment unit.

-Recording medium-
The recording medium is not particularly limited, and plain paper, glossy paper, special paper, cloth, and the like can be used. However, good image formation can be performed using a non-permeable base material.
The non-permeable substrate is a substrate having a surface having low water permeability and low absorptivity, and includes a material that does not open to the outside even if there are many cavities inside, and more quantitatively. And 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 non-permeable substrate, for example, a plastic film such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, a polypropylene, a polyethylene, or a polycarbonate film can be suitably used.
The recording medium is not limited to one used as a general recording medium, and may be a building material such as wallpaper, flooring and tiles, a cloth for clothing such as a T-shirt, a textile, leather and the like. Further, by adjusting the configuration of the path for transporting the recording medium, ceramics, glass, metal, or the like can be used.

  The surface treatment of the recording medium is performed before the landing of the ink. By performing the surface treatment, an acidic group capable of reacting with a cross-linking agent is introduced into the surface of the recording medium. Then, the cross-linking agent in the ink and the bonded product of the cross-linking agent in the ink and the resin are chemically bonded.

  The introduction of the acidic group into the recording medium is performed using a surface treatment means, and is selected from an ozone oxidation treatment, a plasma irradiation treatment, a corona discharge treatment, an ultraviolet irradiation treatment, an electron beam irradiation treatment, an acid treatment, and an alkali treatment. At least one process is preferred. Among them, corona discharge treatment or plasma irradiation treatment is preferable.

  The plasma irradiation treatment is performed using a plasma irradiation apparatus, and has an effect of breaking the polymerization bond on the surface of the recording medium. As described above, an acidic group can be introduced into a recording medium having a modified surface by selecting a gas type.

  The corona discharge treatment is performed using a corona discharge device. As the corona discharge device, a corona discharge device disclosed in JP-A-2010-241999, JP-A-2005-235448, JP-A-2003-300029, or the like can be used. For example, a pair of inner and outer discharge electrodes are arranged at the center and outer periphery of the gas flow path, and a gas is introduced into the gas flow path, and a corona discharge is generated by applying a high voltage to the pair of discharge electrodes. And a method of blowing a gas flow generated by the corona discharge.

<Ultraviolet irradiation step and ultraviolet irradiation means>
The ultraviolet irradiation step is a step of irradiating the recording medium from which the ink has been ejected with ultraviolet rays, and is performed by an ultraviolet irradiation unit.
UV irradiation generates an acid from the photoacid generator in the ink, which promotes chemical bonding between the acidic groups on the surface of the recording medium and the crosslinker in the ink, or the bond between the crosslinker and the resin in the ink. Thus, adhesion, scratch resistance, and chemical resistance are improved.
The ultraviolet irradiation means is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a known ultraviolet irradiation device.

<Other steps and other means>
The other steps are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a control step.
Other means are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a control means.

<Application>
The application of the ink used in the present invention is not particularly limited as long as the ink is generally used in the field, and can be appropriately selected according to the purpose. For example, molding resins, paints, adhesives, and insulating materials , Release agents, coating materials, sealing materials, various resists, various optical materials, and the like.
Further, it can be used not only for forming a two-dimensional character or image and a design coating film on various base materials but also as a three-dimensional modeling material for forming a three-dimensional three-dimensional image (three-dimensional modeled object). This three-dimensional molding material may be used as a binder between powder particles used in a powder lamination method for performing three-dimensional molding by repeatedly curing and laminating a powder layer, for example. ) May be used as a three-dimensional constituent material (model material) or a support member (support material).

As a three-dimensional modeling apparatus for modeling a three-dimensional molded article using the ink used in the present invention, a known three-dimensional modeling apparatus can be used, and is not particularly limited. An apparatus provided with a discharge unit, an active energy ray irradiation unit, or the like can be used.
The present invention also includes a molded product obtained by processing a cured product obtained by curing an ink or a structure in which the cured product is formed on a substrate. The molded product is obtained by subjecting a cured product or a structure formed into a sheet or a film, for example, to a molding process such as a heat drawing or a punching process. -It is suitably used for applications that require molding after decorating the surface, such as electronic equipment, meters such as cameras, and panels for operation units.

<Image formation>
The image formed product of the present invention has a recording medium and an image layer on the recording medium,
The image layer includes a crosslinking agent capable of reacting with an acidic group, and a resin having an acidic group,
The recording medium has an acidic group capable of reacting with the crosslinking agent on the surface of the recording medium.
By using the image forming apparatus and the image forming method, an image can be formed on a recording medium to obtain an image formed product.

<Recording device and recording method>
The ink of the present invention can be suitably used in various recording apparatuses using an ink jet recording system, for example, a printer, a facsimile apparatus, a copying apparatus, a combined printer / fax / copier machine, and a three-dimensional printing apparatus.
In the present invention, a recording device and a recording method are a device capable of discharging ink, various processing liquids, and the like to a recording medium, and a method of performing recording using the device. The recording medium means a medium to which ink and various processing liquids can be temporarily attached.
This recording apparatus can include not only a head portion for discharging ink, but also means for feeding, transporting, and discharging a recording medium, and other devices such as a pre-processing device and a post-processing device. .
In addition, the recording apparatus may include an ultraviolet irradiation device that irradiates the recording medium on which the ink has been ejected with ultraviolet light as necessary.
The recording apparatus and the recording method may include a heating unit used in the heating step and a drying / curing unit used in the drying step.
Further, the recording apparatus and the recording method are not limited to those in which a significant image such as a character or a graphic is visualized by ink. For example, those that form a pattern such as a geometric pattern and the like that form a three-dimensional image are also included.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise limited.
Furthermore, this recording apparatus can use not only a desktop type but also a wide recording apparatus that can print on an A0 size recording medium, or a continuous paper wound in a roll shape as a recording medium. It also includes a simple continuous printer.

An example of the recording apparatus will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective explanatory view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanism section 420 is provided inside an exterior 401 of the image forming apparatus 400. Each ink storage section 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is made of, for example, an aluminum laminate film. It is formed by a packaging member. The ink storage unit 411 is stored in a storage container case 414 made of, for example, plastics. Thus, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided behind the opening when the cover 401c of the apparatus main body is opened. The main tank 410 is detachably mounted on the cartridge holder 404. Accordingly, the ink discharge ports 413 of the main tank 410 and the discharge heads 434 for the respective colors communicate with each other via the supply tubes 436 for the respective colors, and the ink can be discharged from the discharge heads 434 to the recording medium.

Here, another example of the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 3 is an explanatory plan view of a mechanism of the image forming apparatus of the present invention.
This image forming apparatus is a serial type ink jet recording apparatus, and a carriage 3 is movably held by a main guide member 1 and a not-shown sub-guide member which are laid on left and right side plates (not shown). Then, the main scanning motor 5 reciprocates in the main scanning direction (carriage moving direction) via a timing belt 8 bridged between the driving pulley 6 and the driven pulley 7.
The carriage 3 is equipped with recording heads 4a and 4b (hereinafter, referred to as "recording heads 4" when no distinction is made) composed of liquid ejection heads. The recording head 4 ejects, for example, yellow (Y), cyan (C), magenta (M), and black (K) ink droplets. The recording head 4 has a nozzle row composed of a plurality of nozzles arranged in a sub-scanning direction orthogonal to the main scanning direction, and is mounted with the droplet ejection direction facing downward.

The recording head 4 has, for example, two nozzle rows Na and Nb each having a plurality of nozzles 4n arranged as shown in FIG. One nozzle row Na of the recording head 4a discharges black (K) droplets, and the other nozzle row Nb discharges cyan (C) droplets. One nozzle row Na of the recording head 4b discharges magenta (M) droplets, and the other nozzle row Nb discharges yellow (Y) droplets.
As the liquid ejection head constituting the recording head 4, for example, a piezoelectric actuator such as a piezoelectric element, or a thermal actuator using an electrothermal conversion element such as a heating resistor and utilizing a phase change due to liquid film boiling can be used. .
On the other hand, a transport mechanism 51 for transporting the sheet 10 facing the recording head 4 includes a transport belt 12 as transport means. The transport belt 12 is an endless belt, and is stretched between a transport roller 13 and a tension roller 14.
Then, the transport belt 12 is rotated by the sub-scanning motor 16 via the timing belt 17 and the timing pulley 18 to rotate the transport roller 13, so that the transport belt 12 moves in the sub-scanning direction. The transport belt 12 is charged (charged) by a charging roller (not shown) while moving around.
Further, on one side of the carriage 3 in the main scanning direction, a maintenance and recovery mechanism 20 for maintaining and recovering the recording head 4 is arranged on the side of the transport belt 12, and on the other side, the recording head 4 is arranged on the side of the transport belt 12. The empty discharge receivers 21 for performing the idle discharge are arranged respectively.
The maintenance / recovery mechanism 20 is, for example, a cap member 20a for capping the nozzle surface (the surface on which the nozzle is formed) of the recording head 4, a wiper member 20b for wiping the nozzle surface, and ejecting droplets that do not contribute to image formation (not shown). It is composed of an empty discharge receiver and the like.
An encoder scale 23 having a predetermined pattern is arranged between both side plates along the main scanning direction of the carriage 3, and the carriage 3 is provided with an encoder sensor 24 composed of a transmission type photo sensor for reading the pattern of the encoder scale 23. Provided. The encoder scale 23 and the encoder sensor 24 constitute a linear encoder (main scanning encoder) that detects the movement of the carriage 3.
A code wheel 25 is mounted on the shaft of the transport roller 13, and an encoder sensor 26 composed of a transmission type photo sensor for detecting a pattern formed on the code wheel 25 is provided. The code wheel 25 and the encoder sensor 26 constitute a rotary encoder (sub-scanning encoder) that detects the moving amount and the moving position of the conveyor belt 12.
In the image forming apparatus configured as described above, the paper 10 is fed from a paper feed tray (not shown) onto the charged transport belt 12 and is attracted, and the paper 10 is moved in the sub-scanning direction by the orbital movement of the transport belt 12. Conveyed.
Therefore, by driving the recording head 4 in accordance with the image signal while moving the carriage 3 in the main scanning direction, ink droplets are ejected onto the stopped paper 10 to record one line. Then, after the paper 10 is conveyed by a predetermined amount, recording of the next line is performed.
Upon receiving a recording end signal or a signal indicating that the rear end of the sheet 10 has reached the recording area, the recording operation ends, and the sheet 10 is discharged to a discharge tray (not shown).

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

  A recording medium, a medium, and a printed material are all synonyms.

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

(Preparation Example 1)
<Preparation of cyan pigment dispersion>
After premixing the following formulation mixture, it was circulated and dispersed for 7 hours in a disk-type bead mill (KDL type, Shinmaru Enterprises Co., Ltd., using zirconia balls of 0.3 mm in diameter) to obtain a cyan pigment dispersion.
・ Cyan pigment: 15 parts by mass ・ Anionic surfactant (Pionin A-51-B, manufactured by Takemoto Yushi Co., Ltd.): 2 parts by mass ・ Ion exchange water: 83 parts by mass

(Production Example 1)
-Preparation of Ink 1-
An organic solvent, a cross-linking agent, a cyan pigment dispersion, an acrylic resin emulsion, a surfactant, and ion-exchanged water shown in Table 1 were added, and mixed and stirred to prepare an ink solution.
The obtained ink solution was filtered to remove coarse particles and foreign substances, thereby preparing Ink 1.

(Production Examples 2 to 17)
-Preparation of Inks 2 to 17-
Ink 1 to 17 were produced in the same manner as in Production Example 1, except that the composition and content of the inks shown in Tables 1 to 4 were changed.

  Next, Tables 1 to 4 collectively show the compositions and contents of the inks 1 to 17.

The detailed contents of the components in the inks 1 to 17 in Tables 1 to 4 are as follows.
-Resin emulsion-
Acrylic resin emulsion (Nippon Gohsei Chemical Co., Ltd., Movinyl 7470, solid content concentration 44% by mass, resin having acidic group)
Acrylic-silicone resin emulsion (Nippon Synthetic Chemical Co., Ltd., Movinyl 7110, solid content concentration 46% by mass, resin having acidic group)
Styrene-acrylic resin emulsion (Nippon Gohsei Chemical Co., Ltd., Movinyl 972, solid content concentration 50% by mass, resin having an acidic group)
-Surfactant-
・ Silicone surfactant (BYK348, manufactured by BYK)
-Crosslinking agent-
・ Carbodiimide (Nisshinbo Chemical Inc., E-03A)
・ Oxazoline (Nippon Shokubai Co., Ltd., Epocross K-2020E)
-Photoacid generator-
・ WPAG-367 (manufactured by Wako Pure Chemical Industries, Ltd.)

(Examples 1 to 8 and Comparative Examples 1 to 9)
<Image formation>
Each of the produced cyan inks was filled in an ink jet printer (device name: IPSiO GXe5500 modified machine, manufactured by Ricoh Co., Ltd.), and a solid image (1200 dpi × 1200 dpi) was printed.
The IPSiO GXe5500 modified machine enables the IPSiO GXe5500 machine to reproduce a print equivalent to a print speed of 30 m ² / hr with a print width of 150 cm in A4 size, and to change the drying temperature before, during, and after recording. It has been remodeled. The drying temperature at the time of recording was set to 55 ° C., and the surface temperature of the recording medium at the time of recording was adjusted (heat-drying treatment) to 50 ° C., and solid images were formed on the recording media shown in Tables 5 to 8. Formed.
In Examples 7 and 8, and Comparative Examples 4, 5, and 9, a modified IPSiO GXe5500 was used so that ultraviolet irradiation could be performed during image formation.

Details of the recording media shown in Tables 5 to 8 are as follows.
<Recording medium>
Recording medium 1: polyvinyl alcohol (PVA) sheet, having acidic groups on the surface.
Recording medium 2: polypropylene (PP) sheet recording medium 3: cotton: having an acidic group on the surface, having an acidic group on the surface.
Recording medium 4: polyethylene (PE) fiber

<Adhesion test>
Adhesion of the prepared sample according to JIS K5600-5-6 [General Paint Test Method-Part 5: Mechanical properties of coating film-Section 6: Adhesion (cross cut method)] according to the following criteria Was evaluated. The results are shown in Tables 5 to 8.
[Evaluation criteria]
：: The edge of the cut is completely smooth, and there is no peeling at any grid eyes. ：: Small peeling of the coating film at the intersection of the cut is observed. X: The coating film is along the edge of the cut and / or at the intersection. Peeled off at

<Scratch resistance test>
The evaluation of the abrasion resistance was carried out according to JIS K5701 (ISO 11628) (specified for the method of testing inks, colored samples, and printed materials used in lithographic printing), a Gakushin-type friction fastness tester (Tester Sangyo Co., Ltd.) (Manufactured by the company).
The evaluation method was as follows. A gold width (No. 3) was placed on the surface of the coating film, rubbed 20 times with a load of 500 g, and visually observed for peeling and scratches on the surface of the coating film after rubbing, and evaluated according to the following criteria. did. The results are shown in Tables 5 to 8.
[Evaluation criteria]
：: No peeling of the coating film was observed after the rubbing of the metal, or the base was not visible even if the peeling of the coating was recognized. 未 満: The base was exposed to less than 1/4 due to the peeling of the coating after the rubbing of the metal. ×: The base was exposed by 1/4 or more due to peeling of the coating film after rubbing with a metal cloth.

<Discharge stability>
The ink was ejected using the above-described inkjet printer. Discharge was continuously performed for 48 hours on a polyethylene terephthalate (PET) film as a recording medium. At this time, the occurrence of missing dots, bent flight, or scattering of ink was visually observed and evaluated according to the following criteria. The results are shown in Tables 5 to 8.
[Evaluation criteria]
：: The number of missing dots, flight bending, or ink scattering was less than 50 times. ×: The number of missing dots, flying bending, or ink scattering was 50 times or more.

<Ethanol resistance>
A solid image was printed on each recording medium described in Tables 5 to 8 using each ink, and then dried at 80 ° C. for 1 hour. Thereafter, a cotton swab was impregnated with a 50% by mass aqueous solution of ethanol, and the solid portion of the image was rubbed 20 times. The results are shown in Tables 5 to 8.
[Evaluation criteria]
◎: No peeling was seen on the solid portion of the image, and no dirt was seen on the cotton swab. ○: No peeling was found on the solid portion of the image, but dirt was slightly attached to the swab. No ×: Ink dissolution is seen in the solid coating film of the image

  From the results of Tables 5 to 8, Examples 1 to 8 were superior to Comparative Examples 1 to 9 in that the image formed product had good scratch resistance, adhesion, and ethanol resistance, and was excellent in ejection stability. It has been found that an image forming method can be provided.

Aspects of the present invention are, for example, as follows.
<1> including a discharging step of discharging an ink containing a crosslinking agent capable of reacting with an acidic group and a resin having an acidic group onto a recording medium,
An image forming method, wherein the recording medium has an acidic group capable of reacting with the crosslinking agent on a surface of the recording medium.
<2> The image forming method according to <1>, further including a surface treatment step of performing one of corona discharge treatment and plasma irradiation treatment on the recording medium before the ink lands on the recording medium. .
<3> The image forming method according to any one of <1> to <2>, wherein the crosslinking agent is at least one of a compound having an oxazoline group and a compound having a carbodiimide group.
<4> The image forming method according to any one of <1> to <3>, wherein the ink further contains a photoacid generator.
<5> The image forming method according to <4>, further including an ultraviolet irradiation step of irradiating the recording medium onto which the ink is ejected with ultraviolet light.
<6> The image forming method according to any one of <1> to <5>, wherein the ink is an inkjet recording ink.
<7> having a cross-linking agent capable of reacting with an acidic group, and a discharging unit for discharging an ink containing a resin having an acidic group onto a recording medium,
The image forming apparatus is characterized in that the recording medium has an acidic group capable of reacting with the crosslinking agent on the surface of the recording medium.
<8> The image forming apparatus according to <7>, further including a surface treatment unit that performs one of a corona discharge process and a plasma irradiation process on the recording medium before the ink lands on the recording medium. .
<9> The image forming apparatus according to any one of <7> to <8>, wherein the crosslinking agent is at least one of a compound having an oxazoline group and a compound having a carbodiimide group.
<10> The image forming apparatus according to any one of <7> to <9>, wherein the ink further contains a photoacid generator.
<11> The image forming apparatus according to <10>, further including an ultraviolet irradiation unit configured to irradiate the recording medium onto which the ink is ejected with ultraviolet light.
<12> The image forming apparatus according to any one of <7> to <11>, wherein the ink is an inkjet recording ink.
<13> having a recording medium and an image layer on the recording medium,
The image layer includes a crosslinking agent capable of reacting with an acidic group, and a resin having an acidic group,
The image forming product, wherein the recording medium has an acidic group capable of reacting with the crosslinking agent on the surface of the recording medium.

  According to the image forming method according to any one of <1> to <6>, the image forming apparatus according to any one of <7> to <12>, and the image forming product according to <13>, The conventional problems can be solved and the object of the present invention can be achieved.

400 Image forming apparatus 401 Exterior 401c Cover 404 Cartridge holder 410, 410k, 410c, 410m, 410y Main tank 411 Ink storage unit 413 Ink discharge port 414 Storage container case 420 Mechanism unit 434 Discharge head 436 Supply tube L Ink storage container

Japanese Patent No. 622298 Japanese Patent No. 5837765

Claims (7)

Including a cross-linking agent capable of reacting with an acidic group, and an ejection step of ejecting an ink containing a resin having an acidic group onto a recording medium,
An image forming method, wherein the recording medium has an acidic group capable of reacting with the crosslinking agent on the surface of the recording medium.   The image forming method according to claim 1, further comprising a surface treatment step of performing one of corona discharge treatment and plasma irradiation treatment on the recording medium before the ink lands on the recording medium.   The image forming method according to claim 1, wherein the crosslinking agent is at least one of a compound having an oxazoline group and a compound having a carbodiimide group.   The image forming method according to claim 1, wherein the ink further contains a photoacid generator.   5. The image forming method according to claim 4, further comprising an ultraviolet irradiation step of irradiating the recording medium onto which the ink has been ejected with ultraviolet rays. A cross-linking agent capable of reacting with an acidic group, and an ejection unit that ejects an ink containing a resin having an acidic group onto a recording medium,
An image forming apparatus, wherein the recording medium has an acidic group capable of reacting with the crosslinking agent on the surface of the recording medium. A recording medium, having an image layer on the recording medium,
The image layer includes a crosslinking agent capable of reacting with an acidic group, and a resin having an acidic group,
An image-formed product, wherein the recording medium has an acidic group capable of reacting with the crosslinking agent on the surface of the recording medium.