JPH1095158A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method utilizing the ink jet type method in which the generation of the nozzle clogging of an ink jet head in an ink jet type image forming device forming a problem heretofore is eliminated and the restrictions for the selection of a material to be used, for example, a colored material and/or other very fine powders or the like are extremely few. SOLUTION: When ink is jetted on a material to be recorded in compliance with printing information signals by an ink jet type method and a latent image is formed on the material to be recorded preliminarily and then an image is developed by colored or colorless powder or a mixture of them, a curable resin composition composed of a (meth)acrylic polymer and a (meth)acrylic monomer of number-average molecular weight of 1000 or less having unsaturated double bonds in molecules is used as the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method using an ink jet system.

[0002]

2. Description of the Related Art Among non-impact recording methods such as a laser printer using an electrophotographic method, high-speed recording is possible and printing is possible without any processing on plain paper. There has been remarkable progress in the recording method of the ink jet system capable of reducing the cost and the cost, and various types of ink jet recording apparatuses have been developed and commercialized.

In the ink jet recording method, recording is performed by flying small droplets of ink as a recording material and attaching the ink droplets to a recording material. The method for controlling the flight direction is roughly classified into several methods. Broadly speaking, ink droplets are continuously generated regardless of the presence or absence of an information signal, and the continuously generated ink droplets are selectively used in accordance with a print information signal. The method is called an on-demand type in which ink droplets are ejected and fly.

Each of the above-mentioned various ink jet systems has its own characteristics and advantages and disadvantages. However, nozzle clogging due to the precipitation of dyes, which are coloring components present in the ink, or coarse particles of pigments, etc., occurs in any of the ink jet systems. There is also a possibility that this may occur in the system, and many researchers continue to study methods for preventing the nozzle clogging, and various solutions have been proposed. For example, there is a method of covering the ink discharge nozzle when not in use, etc.
These methods are not fundamental, and after a long pause, nozzle clogging often still occurs,
The fact is that it has not been completely solved.

Further, in consideration of the above-mentioned problem of nozzle clogging, there is a limitation that a material which can be dissolved or easily dispersed in an ink solvent must be selected as a material to be used as a coloring agent. In order to prevent the dispersion from clogging the nozzle, a very advanced dispersion technique having an average particle diameter of about 0.05 μm is required. Further, it is necessary to give due consideration to the dispersant so that coarse particles which cause nozzle clogging due to agglomeration of primary particles due to aging do not occur.

In order to solve these problems, it is necessary to remove a coloring agent or a resin which causes clogging from the constituent materials of the ink, or to prepare an ink to which an adhesive is added and discharge these inks by ink-jetting. A method for adhering a specific powder onto ink to obtain various characteristics is disclosed in
-61494 and JP-A-3-89591. However, since the solubility and affinity of the powder in the ink liquid are utilized, usable powders are greatly restricted. Is mixed with a solvent, it is hardly sufficient in terms of operability and stability, such as adjustment of ejection performance from an inkjet head and elimination of nozzle clogging due to drying of ink around the head.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an ink jet system for printing by attaching ink to a recording material in accordance with a print information signal. By providing an image-forming material having excellent dischargeability and good adhesion to the recording material and powder, the ink discharge head is formed by coarse particles of dye precipitates and pigments present in the ink as coloring components. In order to eliminate clogging, and also to solve problems that require advanced dispersion technology, so as not to contain coarse particles even for materials selected for the purpose of ink, and for the purpose of coloring In addition to the materials described above, various materials having various resistances and / or various functions that are usually difficult to make into ink for inkjet can be freely selected. It is intended to broaden the use range significantly.

[0008]

Means for Solving the Problems The inventors of the present invention have studied to solve the above problems, and as a result, have found that good ejection properties from the ink jet head and good adhesion to the recording material and powder are obtained. An imaging material has been found. That is, the present invention
When the ink is ejected onto the recording material in accordance with the ink jet method in accordance with the print information signal and a latent image is formed on the recording material in advance, when visualizing with a colored or colorless powder, or a mixture thereof, The ink has a (meth) acrylic polymer and a number average molecular weight of 100 having an unsaturated double bond in the molecule.
The present invention relates to an image forming material, which is a curable resin composition comprising 0 or less (meth) acrylic monomer.

Hereinafter, the present invention will be described in more detail. The (meth) acrylic polymer of the present invention may be a homopolymer or a copolymer of an alkyl acrylate, a copolymer of an alkyl acrylate and another monomer copolymerizable therewith, or a copolymer thereof. Mixtures are mentioned. Other monomers copolymerizable with the alkyl acrylate include styrene, vinyl acetate, (meth) acrylic acid, alkyl (meth) acrylate, (meth) acrylonitrile, (meth) acrylamide, and (meth) acrylic acid. ) 2-hydroxyethyl acrylate, glycidyl (meth) acrylate, and the like.

In the present invention, (meth) having a number average molecular weight of 1000 or less having one or more unsaturated double bonds in the molecule.
The acrylic monomer (B) is used for adjusting the viscosity and curability of the solventless liquid resin composition.
Examples of such (meth) acrylic monomer (B) include methyl (meth) acrylate, butyl (meth) acrylate, 2hydroxyethyl (meth) acrylate,
Monofunctional (meth) acrylic monomers such as phenoxyethyl (meth) acrylate, methylphenoxy (meth) acrylate, and benzyl (meth) acrylate;

[0011] Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3 butylene glycol di ( (Meth) acrylate, 1,6 hexanediol di (meth) acrylate, 1,9 nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2,2bis [4-{(meth) acryloxy diethoxy} Phenyl] propane, 2,2
Bis [4-{(meth) acryloxyethoxy} phenyl] propane, 2,2bis [4-{(meth) acryloxypolyethoxy} phenyl] propane, 2,2bis [4-{(meth) acryloxydipropoxy} Phenyl] propane, 2,2bis [4-{(meth) acryloxypropoxy} phenyl] propane, 2,2bis [4-
{(Meth) acryloxy / polypropoxy} phenyl]
Bifunctional (meth) acrylic monomers such as propane,

Trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, Examples thereof include trifunctional or higher functional (meth) acrylic monomers such as dipentaerythritol hexa (meth) acrylate.

In the case of curing by irradiation with radiation, a known photopolymerization initiator can be added. Examples of the photopolymerization initiator include benzophenone, methylbenzophenone, methyl o-benzoylbenzoate and p-benzoinethyl ether. Is mentioned. These photopolymerization initiators can be used in combination with photopolymerization accelerators such as 4,4'-bis (diethylamino) benzophenone, ethyl N-dimethylaminobenzoate, dimethylethanolamine and glycine. In addition, as long as the effects of the present invention are not impaired, tackifiers, antioxidants, and polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, and benzoquinone are used to control dark reactions and increase the stability during storage. It can also be added. Electron beam irradiation and ultraviolet irradiation are preferably performed in an inert atmosphere such as nitrogen or carbon dioxide in order to prevent oxygen inhibition.
The electron beam irradiation amount is usually about 0.5 to 20 Mrad.

The ink used in the present invention is adjusted to the optimum viscosity and surface tension depending on the ink jet system to be applied. Therefore, water, alcohol, ether, glycol, ketone, ester, and hydrocarbon are used. And the like, organic solvents, various monomers, and mixtures thereof.

Particularly when the ink is water-based, the aqueous solvents used include ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, polyethylene glycol, glycerin, tetraethylene glycol, dipropylene glycol, ketone alcohol, diethylene glycol monobutyl ether, and ethylene glycol. Glycol monobutyl ether, ethylene glycol monoethyl ether, 1,2-hexanediol,
N-methyl-2-pyrrolidone, substituted pyrrolidone, 2,
4,6-hexanetriol, tetrafurfuryl alcohol, 4-methoxy-4-methylpentanone, and the like. In particular, when dryness on a recording material is required, alcohols such as methanol, ethanol, and isopropyl alcohol can be used for the purpose of speeding up drying.

In the case of an aqueous system, a fungicide can be added to prevent the generation of mold. As an antifungal agent, sodium dehydroacetate, sodium benzoate,
Sodium pyridinethione-1-oxide, zinc pyridinethione-1-oxide, 1,2-benzisothiazolin-3-one, 1-benzisothiazolin-3-one amine salt and the like are used. Further, a pH adjuster for obtaining stability of the ink and stability with a liquid pipe in the apparatus,
An antifoaming agent and other additives that prevent the generation of bubbles during the production, movement, and circulation of the ink in the apparatus can be used within a range that does not hinder use.

The ink adjusted as described above is ejected using an ink-jet method, a latent image is formed on a recording material in advance, and powder is brought into direct contact with the latent image with a brush or a roller. Alternatively, the latent image is visualized by indirectly contacting it with dust or static electricity by sieving. At the time when the powder is brought into contact with the latent image portion, the degree of drying of the ink on the recording material is not particularly specified, and the wettability of the powder in a solvent is used in an undried state depending on the powder used. May be contacted.

The ink of the present invention has a viscosity of 0.002 to 1 at 25 ° C., depending on the type of the ink jet apparatus.
It is preferably adjusted to 00 poise, preferably 0.008 to 50 poise. If the viscosity is lower or higher than this, it is not preferable because it is difficult to form a latent image by an ink jet method.

Excess powder attached to the non-image area is blown off or sucked by air, or removed by an adhesive roller or the like. For the visualized powder, no particular fixing step is required, and the powder particles adhering to the ink are directly impregnated or adhered to the recording material, but are further used in ordinary copying machines or printers. By using a fixing method using heat or pressure, or using a fixing device, the adhesion between the recording material and the powder can be further improved. Depending on the application, post-processing such as lamination may be performed to protect the surface.

As the ink jet system that can be used in the present invention, various known systems and apparatuses can be applied. For example, in the case of a continuous type in which ink droplets are continuously ejected and formed into particles, the present invention can be applied to a charge control type, a divergence control type, and the like. In addition, the on-demand type can be applied to a pressure control method of ejecting ink droplets from an orifice by mechanical vibration of a piezoelectric vibrating element, a heat control method using a heating resistor element, and the like. It is not limited.

The recording medium that can be used in the present invention is not particularly limited, and examples thereof include paper, plastic films, metal plates, and wood. In addition, since it is a non-contact method, it can be applied not only to a flat surface or a curved surface but also to an uneven surface or a three-dimensional object.

The powder that can be used in the present invention is not limited at all, and known pigments and dyes conventionally used as powder coloring materials or a mixture of both can be used. For example, as dyes, direct dyes, acid dyes, basic dyes, mordant dyes, metal-containing dyes, vat dyes, sulfur dyes, reactive dyes, disperse dyes,
Alcohol-soluble dyes, oil-soluble dyes, and the like, and in terms of chemical structure, acridine dyes, aniline black, anthraquinone dyes, azine dyes, azo dyes, azomethine dyes, benzo and naphthoquinone dyes, indigoid dyes, indophenol, indoaniline , Indamine, leuco vat dye ester, naphtholimide dye, nigrosine and indulin, nitro and nitroso dye, oxazine and dioxazine dye, oxidation dye, phthalocyanine dye, polymethine dye, quinophthalone dye, tri and diallyl methane dye, thiazine dye, thiazole dye And xanthene dyes.
As organic pigments, nitroso, nitro, phthalocyanine, insoluble azo, poorly soluble azo, soluble azo,
Basic dye lakes, acid dye lakes, vat dye lakes, quinacridones, dioxazines, perylenes,
Isoindolinone type, imidazolone type, pyranthrone type, thioindigo type and the like, and inorganic pigments include carbon black, titanium white, cobalt oxide, barium sulfate, calcium carbonate, magnesium carbonate, navy blue and the like.

Further, metal powder such as gold powder, silver powder, aluminum powder and the like, or metal foil can also be used. Also,
Ceramics, fluorescent substances, magnetic powder, colorless or colored glass beads, etc. can also be used. Further, a colored resin powder (toner) obtained by kneading the above-mentioned dye / pigment with a thermoplastic resin and pulverizing it into fine powder can be used. Alternatively, even if only the thermoplastic resin powder is adhered, a prominent image can be obtained. In any case, the material is not limited to these materials, and is not limited to a material for coloring, and various resistances such as weather resistance, corrosion resistance, and / or ultraviolet light which are usually difficult to make into an ink for inkjet use. Various powders having functions such as absorption and conductivity can be used as the powder material for visualization.

Further, by repeating the steps provided by the present invention and visualizing various powders in accordance with print information, for example, when the powder is a coloring material, a multicolor image is obtained, In such a case, a molded article having higher functionality according to the purpose of use can be obtained.

As a method for producing the above toner that can be used in the present invention, a conventionally known method can be used. As a general method, a thermoplastic resin serving as a binder and a dye / pigment serving as a coloring component are heated and melted and kneaded with a hot roll or the like, cooled, pulverized and classified, and powdered with a particle diameter of 5 to 15 μm. A method of obtaining a material, a method of dissolving a resin serving as a binder, mixing a dye / pigment serving as a coloring component, kneading the mixture with a disperser such as a ball mill and an attritor, drying and pulverizing and classifying the powder having a particle diameter of 5 to 15 μm; There is a method of obtaining a body coloring material. Further, there is no problem in adding a third component other than the dye and pigment when producing the toner.

[0026]

Embodiments will be described below with reference to embodiments. Example 1 41 parts of n-butyl acrylate, 41 parts of 2-ethylhexyl acrylate, 10 parts of vinyl acetate and 8 parts of acrylic acid were copolymerized in toluene, and the solvent was removed to obtain an acrylic polymer. In 100 parts of the obtained acrylic polymer,
N-butylcarbamoyloxyethyl acrylate 60
Parts, polyethylene glycol (molecular weight: about 400) 3 parts, and a photopolymerization initiator “Darocur 117”
3 "(trade name, manufactured by Merck & Co.) was mixed with methyl ethyl ketone and n-hexane in a ratio of 2: 7:
Thus, an ink mixed and dissolved at a weight ratio of 1 was obtained.

This ink is ejected onto high quality paper from a pressure-controlled on-demand type ink jet output device that ejects ink droplets from an orifice by the mechanical vibration of a piezoelectric vibrating element to form a transparent latent image. The latent image was visualized by contacting the powder coloring material prepared by the method. Also,
Excess powder coloring material existing in portions other than the latent image was suctioned by a pneumatic suction device. Thereafter, in a nitrogen atmosphere, ultraviolet rays were irradiated for 1 second at a position of 15 cm from a coating surface side under one 80 W / cm ² high pressure mercury lamp to cure the image area. Styrene-acrylic acid copolymer resin 95 parts Molecular weight (Mn: about 8,0000, Mw: about 200,000) Glass transition point Tg: 63 ° C, degree of polymerization 800 Pigment (Finess RED F2B: manufactured by Toyo Ink Mfg. Co., Ltd.) 5 parts) were heated, melted and kneaded with three hot rolls, and then cooled and pulverized and classified to obtain a powder coloring material having an average particle diameter of 10 μm.

As a result, good dischargeability from the output device, a visualized state, and a cured image were obtained.

Example 2 60 parts of methoxypolyethylene glycol acrylate
2-ethylhexyl acrylate 10 parts, acrylic acid 3
0 parts is azobisisobutyronitrile (AIBN) as an initiator (1% by weight based on the total charged amount of monomers), and isopropyl alcohol / water = 4/1 solvent (concentration at the time of charged monomers: 33% by weight) And the solvent was removed to obtain an acrylic polymer. To 100 parts of the obtained acrylic polymer, 2 hydroxyethyl acrylate 40
And 10 parts of ethylene glycol diacrylate were mixed and dissolved in water, ethanol, and isopropyl alcohol at a weight ratio of 2: 3.5: 3.5: 1 to obtain a sticky liquid.

The liquid is discharged onto a polyester film from a pressure-controlled on-demand type ink jet output device that discharges ink droplets from an orifice by mechanical vibration of a piezoelectric vibrating element to form a transparent latent image. The latent image was visualized by contacting the powder coloring material prepared by the following method. Excess powder coloring material existing in portions other than the latent image was suctioned by a pneumatic suction device. Then 2Mra
The image area was cured by irradiating the electron beam of d. Styrene-acrylic acid copolymer resin 95 parts Molecular weight (Mn: about 8,0000, Mw: about 200,000) Glass transition point Tg: 63 ° C., degree of polymerization 800 Pigment (Lionol Blue FG-7351: Toyo Ink Manufacturing Co., Ltd.) 5 parts) were heated, melted and kneaded with three hot rolls, and then cooled and pulverized to obtain a powder colorant having an average particle diameter of 10 μm.

As a result, good dischargeability from the output device, a visualized state, and a cured image were obtained.

[0032]

As described above, by using the image forming method and the image forming material of the present invention, the nozzle clogging of the ink discharge head in the ink jet type image forming apparatus, which has been a conventional problem, can be solved. Thus, it was possible to provide an image forming method using an ink-jet method which has very few restrictions on selection of a material to be used such as a coloring material and / or other fine powder.

Claims (1)

[Claims] An ink is ejected onto a recording material in accordance with a print information signal by an ink-jet method, a latent image is formed on the recording material in advance, and then a colored or colorless powder or a mixture thereof is developed. When forming an image, the ink is a curable resin composition comprising a (meth) acrylic polymer and a (meth) acrylic monomer having an unsaturated double bond in the molecule and having a number average molecular weight of 1,000 or less. An image forming method, comprising: