JP5515346B2 - Inkjet recording method, inkjet recording apparatus, pretreatment liquid set - Google Patents

Description

The present invention is pretreated jet recording method and an ink jet recording apparatus for effecting recording on a recording medium, and a pretreatment liquid set Ru used for this.

  An inkjet recording method in which pretreatment is performed with a pretreatment liquid containing a polyvalent metal salt or an acid is known (Patent Document 1, etc.). However, in such a conventional ink jet recording method, the image density can be improved by aggregating the colorant with the pretreatment liquid, but there is a problem that the dot diameter is reduced accordingly.

The present invention has thus the dot diameter is reduced, the ink jet can be improved image density recording method and an ink jet recording apparatus, and an object to provide a pretreatment liquid set Ru used for this.

The above-described problems are solved by the following inventions 1) to 3 ).
1) In an inkjet recording method including a step of processing a recording medium prior to recording and a step of recording with an aqueous recording ink, the step of processing the recording medium includes a first step including a polyvalent metal salt and an acid. An ink jet recording method comprising: a step of treating a recording medium using a pretreatment liquid and a second pretreatment liquid containing sodium alginate having a concentration of 5% by weight or less .
2 ) Aqueous recording ink discharge means, first pretreatment liquid storage means containing polyvalent metal salt and acid, and second pretreatment liquid storage means containing 5% by weight or less of sodium alginate And an ink jet recording apparatus comprising: pretreatment means for treating the surface of the recording medium with a first pretreatment liquid and a second pretreatment liquid before discharging the aqueous recording ink by the discharge means.
3) before recording on a recording medium using the aqueous recording ink, a pretreatment liquid set for processing the surface, a first pre-treatment liquid containing a polyvalent metal salt and acid, 5 wt And a second pretreatment solution containing sodium alginate at a concentration of not more than% .

According to the present invention, without the dot diameter decreases, the ink-jet recording method and an ink jet recording apparatus capable of improving the image density, and can provide a pretreatment liquid set Ru used for this.

1 is a schematic diagram of an example of an ink jet recording apparatus according to the present invention. (Side view) 1 is a diagram showing an ink jet recording apparatus according to a first embodiment of the present invention. The figure which shows the inkjet recording device of 2nd Embodiment which concerns on this invention. Schematic including the case (exterior) of the ink cartridge.

Hereinafter, the present invention will be described in detail.
The present invention is to record on a recording medium whose surface is treated with a polyvalent metal salt and an acid and sodium alginate before discharging the aqueous recording ink, and a crosslinking reaction between the polyvalent metal salt and sodium alginate. characterized by causing a thickening operation of sodium alginate with an acid, thereby without the dot diameter is reduced, it is possible to improve image density. The combined use of tripartite and sodium alginate polyvalent metal salt and acid, it is possible to reduce the counter top and the transfer density of the image density. Polyvalent metal salts, and sodium alginate is preferably used as a treatment solution state dissolved in a solvent such as water. In the present invention, Ru with a second pre-treatment solution containing a first pre-treatment solution and sodium alginate containing the polyvalent metal salt and acid.
And as a structure which processes the recording medium surface using such a pre-processing liquid, the structure which apply | coats a pre-processing liquid to a recording medium surface with an application | coating roller, and the structure which discharges a pre-processing liquid to the recording medium surface from an inkjet head And a configuration in which the pretreatment liquid is sprayed from the spray nozzle onto the surface of the recording medium.

As the polyvalent metal salt used in the present invention, polyvalent metal ions such as aluminum ions, barium ions, calcium ions, copper ions, iron ions, magnesium ions, manganese ions, nickel ions, tin ions, titanium ions, zinc ions, Inorganic acids such as hydrochloric acid, oxalic acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, thiocyanic acid, organic carboxylic acids such as acetic acid, succinic acid, lactic acid, fumaric acid, citric acid, salicylic acid, benzoic acid, and organic sulfonic acids And the like. These may be used alone or in combination.
The polyvalent metal salt has a large effect of aggregating constituent components in the aqueous recording ink, and has a large effect of improving optical density, bleeding, and intercolor bleeding. There are preferable polyvalent metal ions depending on the type of polysaccharide polymer, and calcium ions, barium ions and aluminum ions are preferable for sodium alginate.

As the acid used in the present invention, an organic acid is preferable, and an acid having a carboxyl group is particularly preferable. In the case of organic acids, there are many that are produced in the body and contained in foods and the like, and those that are less likely to remain in the human body can be selected. Moreover, since there are many odorless things, it is suitable for the use in a home or an office. Specific examples include succinic acid, citric acid, malic acid, tartaric acid, lactic acid and the like.
The role of the acid in the present invention is a thickening action of sodium alginate in the pretreatment liquid, and contributes to improvement of image fixability. In addition, when the aqueous recording ink contains a carboxyl group-containing resin, the acid reacts with the resin to contribute to high image density and high image quality.
The thickening action of sodium alginate by acid is affected by the pH when both are mixed. The thickening action of sodium alginate occurs in the range of pH 2 to 5, and if it is lowered to less than pH 2, it will precipitate as alginic acid. Therefore, the addition amount of the acid in the present invention is appropriately selected within a range in which the pH when the both are mixed on the recording medium is within 2 to 5.
However, when the water-based recording ink contains a carboxyl group-containing resin, if the amount of acid added is too large, the pigment agglomeration effect due to the reaction with the carboxyl group-containing resin increases, and dots on the recording medium The diameter becomes smaller. This means that the spread of the dots is reduced. In particular, if the solid portion is insufficiently filled, the influence of the background color of the recording medium appears in the image. Therefore, it is necessary to determine the amount of acid added to the pretreatment liquid within a range that does not cause image defects. The amount of addition is preferably 20% by weight or less, more preferably 10% by weight or less, based on the pretreatment liquid. .

Sodium alginate used in the present invention is an essential component for expanding the dot diameter . Sodium A alginic acid for gelling instantaneously on contact with a polyvalent metal salt, that discharges a polyvalent metal salt and sodium alginate as a separate pre-treatment liquid. Either of the discharge orders of the different pretreatment liquids may be first.
In the present invention, the above-described polyvalent metal salt and sodium alginate cause cross-linking reaction (gelation action) and acid thickening action of sodium alginate occurs on the recording medium. Rapid pigment aggregation due to acid can be suppressed, and as a result, the dot diameter can be prevented from becoming smaller. Further, when the sodium alginate is gelled or thickened, the aqueous recording ink can remain in the vicinity of the surface layer of the recording medium, and as a result, high image density and high image quality can be achieved . Polyvalent metal salts, processes the recording medium in combination tripartite acid and sodium alginate Then, strong gel with relatively strong because sodium alginate is thickening is generated by the acid, an effect that the fixing property is improved expectation it can.

Further, the ratio of D-mannuronic acid and L-guluronic acid in sodium alginate greatly affects the gelation ability and gel strength of the polyvalent metal salt and sodium alginate. In order to form a gel with higher strength, it is necessary to increase the ratio of the block polymer formed with L-guluronic acid, and the block formed with D-mannuronic acid with respect to the block polymer formed with L-guluronic acid The polymer ratio is preferably 1 or less, more preferably 0.6 to 0.8.
Moreover, the higher the viscosity of the sodium alginate solution, the higher the gelation ability and gel strength. However, when the viscosity of the sodium alginate solution becomes too high, the application to the recording medium is affected. Therefore, the solution viscosity is appropriately selected within a range that does not affect the application to the recording medium.
Sodium alginate is available as a commercial product, and examples thereof include Kimika Argin K-ULV series and K-High · G series manufactured by Kimika.
The addition amount of sodium alginate, and 5 wt% or less in the pretreatment solution. The proportion of transfer density against the image density exceeds 5 wt% becomes when there Ru worse than those not treated with sodium alginate.

Furthermore, it is preferable to add a surfactant to lower the surface tension of the pretreatment liquid and to foam the pretreatment liquid.
When a liquid pretreatment liquid is to be applied to a recording medium having an uneven surface with an application roller or the like, the thickness of the pretreatment liquid on the surface of the application roller needs to be extremely thin. However, in the contact between the surface of the coating roller and the recording medium having the projections and depressions, a portion where the pretreatment liquid cannot be applied occurs because of poor contact. On the contrary, in order to apply the pretreatment liquid to the entire recording medium having irregularities, if the thickness of the pretreatment liquid on the surface of the application roller is increased, an unnecessary pretreatment liquid is applied depending on the recording medium, In addition to high costs, problems such as curling of the recording medium may occur depending on the type of solvent in the pretreatment liquid. Therefore, it is preferable to apply the pretreatment liquid to the recording medium after foaming it in advance. Surfactant is effective in forming this foam.
There is no restriction | limiting in particular as surfactant, A well-known thing can be used. For example, silicone surfactants, fluorine surfactants, acetylene glycol surfactants and the like can be mentioned. These may be used alone or in combination. The addition amount of the surfactant is preferably 0.01 to 3% by weight, and more preferably 0.5 to 2% by weight with respect to the pretreatment liquid.

  Usually, water or a volatile water-soluble solvent is added to the pretreatment liquid as a solvent. These may be used alone or in combination. However, when water is used alone, depending on the type of the recording medium, paper curling may occur remarkably. In addition, when a volatile water-soluble solvent is used alone, the solvent suddenly volatilizes on the recording medium, which may cause a problem with respect to the dot not spreading and filling. Therefore, it is preferable to select appropriately considering the use conditions and environment. A well-known thing can be used as a volatile water-soluble solvent, For example, methanol, ethanol, etc. are mentioned. These may be used alone or in combination.

The aqueous recording ink contains at least a colorant, a water-soluble organic solvent, a surfactant, and water, but preferably further contains a carboxyl group-containing resin.
As the colorant, a known dye or pigment can be used in the aqueous recording ink. Colorant particles obtained by coating inorganic particles with an organic pigment or carbon black may also be used.
Examples of the method for coating the inorganic particles with carbon black include a submerged drying method by coagulation and precipitation, and a dry mixing method in which a mechanical force is applied while mixing. Examples of the method of coating the inorganic particles with the organic pigment include a method of depositing the organic pigment in the presence of the inorganic particles and a method of mechanically kneading the inorganic particles and the organic pigment. In this case, for example, when coating with an organic pigment having excellent thermal stability, a chemical vapor deposition technique can be used. Further, if necessary, if an organosilane compound layer formed from polysiloxane and alkylsilane is provided between the inorganic particles and the organic pigment, the adhesion between them can be improved.
Examples of the inorganic particles include titanium dioxide, silica, alumina, iron oxide, iron hydroxide, and tin oxide. The inorganic particles preferably have a small aspect ratio, and are particularly preferably spherical. Further, when the color coloring agent is adsorbed on the surface of the inorganic particles, the inorganic particles are preferably colorless and transparent or white. However, when the black coloring agent is adsorbed, black inorganic particles may be used. Absent.
The average primary particle size of the inorganic particles is preferably 100 nm or less, and more preferably 5 to 50 nm.

Examples of the organic pigment covering the inorganic particles include aniline black as a black pigment. Examples of the color pigment include anthraquinone, phthalocyanine blue, phthalocyanine green, diazo, monoazo, pyranthrone, perylene, heterocyclic yellow, quinacridone, and (thio) indigoid.
Among these, phthalocyanine pigments, quinacridone pigments, monoazo yellow pigments, diazo yellow pigments, and heterocyclic yellow pigments are particularly preferable from the viewpoint of color developability.
Examples of the phthalocyanine pigment include copper phthalocyanine blue or a derivative thereof (CI pigment blue 15: 3, CI pigment blue 15: 4), aluminum phthalocyanine, and the like.
Examples of quinacridone pigments include C.I. Pigment Orange 48, C.I. Pigment Orange 49, C.I. Pigment Red 122, C.I. Pigment Red 192, C.I. Pigment Red 202, C.I. Pigment Red 206, C.I. Pigment Red 207, C.I. Pigment Red 209, C.I. Pigment Violet 19, C.I. I pigment violet 42 and the like.
Examples of monoazo yellow pigments include C.I. Pigment Yellow 74, C.I. Pigment Yellow 109, C.I. Pigment Yellow 128, C.I. And CI Pigment Yellow 151.
Examples of the diazo yellow pigment include C.I. Pigment Yellow 14, C.I. Pigment Yellow 16, C.I. CI pigment yellow 17 etc. are mentioned.
Examples of the heterocyclic yellow pigment include C.I. Pigment Yellow 117, C.I. I pigment yellow 138 etc. are mentioned.

The weight ratio of the inorganic particles to the organic pigment or carbon black as the colorant (inorganic particles: colorant) is preferably 3: 1 to 1: 3, and more preferably 3: 2 to 1: 2. If the ratio of the colorant is too small, the color developability and coloring power may be reduced, and if the ratio of the colorant is too large, the transparency and color tone may be deteriorated.
Examples of commercially available colorant particles obtained by coating inorganic particles with an organic pigment or carbon black include silica / carbon black composite materials manufactured by Toda Kogyo Co., Ltd., silica / phthalocyanine C.I. I PB15: 3 composite material, silica / diazo yellow composite material, silica / quinacridone C.I. IPPR122 composite materials and the like can be mentioned, and these can be suitably used because of their small average primary particle size.

For example, when inorganic particles having an average primary particle size of 20 nm are coated with an equal amount of organic pigment, the average primary particle size is about 25 nm. Therefore, if it can be dispersed in the form of primary particles using an appropriate dispersant, a very fine pigment-dispersed ink having a dispersed particle diameter of 25 nm can be produced.
The average primary particle diameter of the colorant particles is preferably 5 to 100 nm and more preferably 30 to 80 nm in the aqueous recording ink. If the average primary particle size is less than 5 nm, the ink may thicken during long-term storage or the colorant particles may agglomerate. If it exceeds 100 nm, the ink may be printed on a medium such as paper or film. In some cases, the printed portion has a reduced saturation and lightness. The primary particle size of the colorant particles means the smallest unit of colorant particles that cannot be pulverized further by mechanical shearing.
The content of the colorant particles in the aqueous recording ink is preferably 1 to 20% by weight, and more preferably 2 to 15% by weight.

The water-based recording ink uses water as a solvent, and further uses a water-soluble organic solvent for the purpose of preventing the ink from drying and improving the dispersion stability. A plurality of these water-soluble organic solvents may be used as a mixture.
Examples of the water-soluble organic solvent include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, and ethylene carbonate. Etc.
Examples of polyhydric alcohols include glycerin, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, and triethylene. Glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, hexylene glycol, trimethylolethane, trimethylolpropane, glycerol, 1,2,3-butanetriol, 1,2, Examples include 4-butanetriol, 1,2,6-hexanetriol, and petriol.

Examples of the polyhydric alcohol alkyl ethers include 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 ether and the like. .
Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of the nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-ptyrolactone, and the like. Can be mentioned.
Examples of amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine and the like.
Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol and the like.

Among these water-soluble solvents, glycerin, diethylene glycol, 1,3-butanediol, and 3-methyl-1,3-butanediol are particularly preferable. These have excellent effects on solubility and prevention of jetting property defects due to water evaporation. In addition, an aqueous recording ink having excellent storage stability and ejection stability can be produced.
The mixing ratio of the colorant particles and the water-soluble organic solvent has a great influence on the stability of ink ejection from the head. If the blending amount of the water-soluble organic solvent is small even though the pigment solid content is large, water evaporation near the ink meniscus of the nozzle proceeds, resulting in ejection failure.

The water-based recording ink may be used in combination with other water-soluble organic solvents such as saccharides and derivatives thereof as necessary, in addition to the water-soluble organic solvent. Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and derivatives thereof. Specific examples include glucose, mannose, fructose, ribose, xylose, trehalose, maltotriose and the like. Here, the polysaccharide means a saccharide in a broad sense and includes substances widely present in nature such as α-cyclodextrin and cellulose.
Examples of saccharide derivatives include reducing sugars and oxidized sugars of the saccharides. Among these, sugar alcohols are preferable, and specific examples include maltitol and sorbit.
The saccharide content is preferably from 0.1 to 40% by weight, more preferably from 0.5 to 30% by weight, based on the aqueous recording ink.

There is no restriction | limiting in particular as surfactant, According to the objective, it can select suitably from surfactants which do not impair dispersion stability by the combination of the kind of coloring agent, a wetting agent, a penetrant, etc. In particular, when printing on printing paper, a fluorine-based surfactant or a silicone-based surfactant having a low surface tension and high leveling properties is preferable, and a fluorine-based surfactant is particularly preferable.
Examples of the fluorosurfactant include 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 in the side chain. The polyoxyalkylene ether polymer compound is particularly preferred because of its low foamability.

Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate.
Examples of the perfluoroalkyl carboxylic acid compound include perfluoroalkyl carboxylic acid and perfluoroalkyl carboxylate.
Examples of the perfluoroalkyl phosphate compound include perfluoroalkyl phosphate esters, perfluoroalkyl phosphate salts, and the like.
Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Examples thereof include salts of oxyalkylene ether polymers.
As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.

  As a fluorine-type surfactant, what was synthesize | combined suitably may be used, or a commercial item may be used. As a commercial item, for example, Surflon series (S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145) manufactured by Asahi Glass Co., Ltd., Sumitomo 3M Fullrad series (FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431) manufactured by Dainippon Ink, Inc. F-470, F-1405, F-474), Dupont Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Neos FT-110, Examples thereof include FT-250, FT-251, FT-400S, FT-150, FT-400SW, and PF-151N manufactured by Omninova. Among these, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd. are particularly preferable because of good remarkably improved printing quality, particularly color developability and leveling on paper. And PF-151N manufactured by Omninova.

There is no restriction | limiting in particular as said silicone type surfactant, According to the objective, it can select suitably. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, and side chain both terminal modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as an aqueous surfactant.
As a silicone type surfactant, what was synthesize | combined suitably may be used, or a commercial item may be used. Commercially available products such as Big Chemie, Shin-Etsu Silicone, Toray Dow Corning Silicone are readily available.
Further, as the silicone surfactant, a polyether-modified silicone surfactant can be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylpolysiloxane.
As a polyether modified silicone compound, what was synthesize | combined suitably may be used, or a commercial item may be used. As a commercial item, Shin-Etsu Chemical Co., Ltd. KF-618, KF-642, KF-643 etc. are mentioned, for example.

In addition to the fluorine-based surfactant and the silicone-based surfactant, anionic surfactants, nonionic surfactants, amphoteric surfactants, and the like can be used.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, succinate sulfonate, laurate, polyoxyethylene alkyl ether sulfate, and the like.
Examples of the nonionic surfactant include acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, and the like.
Examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3, 5-dimethyl-1-hexyn-3-ol and the like. Moreover, as the commercial item, the Surfynol series (104, 82, 465, 485, TG) by Air Products, etc. are mentioned, for example.

  Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, lauryl dimethyl amine oxide, myristyl dimethyl amine oxide, stearyl dimethyl amine oxide, dihydroethyl lauryl amine oxide, Polyoxyethylene coconut oil alkyldimethylamine oxide, dimethylalkyl (coconut) betaine, dimethyl lauryl betaine and the like can be mentioned. As commercially available products, for example, Nikko Chemicals, Nippon Emulsion, Nippon Shokubai, Toho Chemical, Kao, Adeka, Lion, Aoki Yushi, Sanyo Kasei, etc. can be easily obtained. .

The various surfactants may be used alone or in combination. Even if it is not easily dissolved in the water-based recording ink alone, it may be solubilized by mixing a plurality of inks and can exist stably.
The content of the surfactant in the aqueous recording ink is preferably 0.01 to 3% by weight, and more preferably 0.5 to 2% by weight. However, the total content of the components that are higher in boiling point than water and 25 ° C. is preferably 20% by weight or less, and more preferably 15% by weight or less. When the total content is less than 0.01% by weight, the effect of adding the surfactant may be lost. When the total content exceeds 3% by weight, the permeability to the recording medium becomes unnecessarily high, and the image density decreases. There may be a show-through.

The aqueous recording ink preferably contains a carboxyl group-containing resin. As a result, as described above, the acid in the pretreatment liquid reacts with the carboxyl group-containing resin to cause aggregation of the pigment on the recording medium, so that the image density and image quality can be improved.
Examples of the carboxyl group-containing resin include a maleic acid resin, a styrene-maleic acid resin, a rosin-modified maleic acid resin, an alkyd resin, and a modified alkyd resin. These commercially available products include Arumagawa Chemical's Marquide series (maleic acid resin), Alastar series (styrene-maleic acid resin), Harima Kasei's Harimac series (rosin-modified maleic acid resin), Halifter Le series (alkyd resin, modified alkyd resin).
The addition form of the carboxyl group-containing resin is not particularly limited, and may be added in a form in which the pigment as the colorant is included in the carboxyl group-containing resin, or the carboxyl group-containing resin may be added separately from the colorant. May be.

In addition to the above-described components, a known penetrant, polymer particles, pH adjuster, antiseptic / antifungal agent, rust preventive agent and the like can be added to the aqueous recording ink, if necessary.
As the penetrant, a polyol compound or glycol ether compound having 8 to 11 carbon atoms is preferably used. These are partially water-soluble compounds having the effect of increasing the penetration rate into paper and preventing bleeding and having a solubility of 0.1 to 4.5% by weight in water at 25 ° C.
Examples of the polyol compound having 8 to 11 carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Examples of the glycol ether compound include polyhydric alcohol alkyl ether compounds and polyhydric alcohol aryl ether compounds.
Examples of the polyhydric alcohol alkyl ether compound include 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 ether and the like. .
Examples of the polyhydric alcohol aryl ether compound include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
These penetrants are components that have a higher boiling point than water and are liquid in ink at 25 ° C., and the content in the aqueous recording ink is preferably 0 to 10% by weight, and 0.5 to 5% by weight. Is more preferable.

As the polymer particles, those having a film-forming property are used. Here, the film-forming property means the property that when polymer particles are dispersed in water to form an emulsion, a resin film is formed when water in the aqueous emulsion is evaporated.
When such polymer particles are contained, the polymer particles form a film when the volatile components in the aqueous recording ink evaporate, and serve to firmly fix the colorant in the ink to the recording medium. . Thereby, it is possible to realize an image excellent in abrasion resistance and water resistance.
In order to form a film at room temperature, the polymer particles preferably have a minimum film-forming temperature of 30 ° C. or lower, more preferably 10 ° C. or lower. Here, the minimum film-forming temperature means that a polymer emulsion obtained by dispersing polymer particles in water is thinly cast on a metal plate such as aluminum, and when the temperature is raised, it is transparent and continuous. It means the lowest temperature at which a film is formed.
The volume average particle diameter of the polymer particles is preferably 5 to 200 nm, more preferably 10 to 100 nm.
A polymer particle having a single particle structure can be used. For example, when an alkoxysilyl group is contained in the emulsion particles, it comes into contact with water remaining due to fusion of the emulsions due to water evaporation during the coating film formation process, and hydrolyzes to form silanol groups. Moreover, the alkoxysilyl group in which a silanol group remains, or silanol groups can react, and the firm crosslinked structure by a siloxane bond can be formed. When reactive functional groups coexist in the polymer fine particles as described above, a network structure can be formed by reacting these functional groups during film formation without adding a curing agent.

It is also possible to use polymer particles having a core-shell structure comprising a core part and a shell part surrounding the core part. The core-shell structure here means a form in which two or more kinds of polymers having different compositions are present in phase separation in the particles. Therefore, the shell portion may not only cover the core portion completely, but may cover a portion of the core portion. Further, a part of the polymer of the shell part may form a domain or the like in the core particle. Further, it may have a multilayer structure of three or more layers including one or more layers having different compositions between the core portion and the shell portion.
The polymer particles can be obtained by a known method such as emulsion polymerization of an unsaturated vinyl monomer (unsaturated vinyl polymer) in water containing a polymerization catalyst and an emulsifier.
The content of the polymer particles in the aqueous recording ink is preferably 0.5 to 20% by weight, and more preferably 1 to 5% by weight. If the content is less than 0.5% by weight, the rub resistance and water resistance improving function may not be sufficiently exhibited. If the content exceeds 20% by weight, ink discharge may occur due to increase in viscosity due to drying or adhesion of polymer components. May become unstable and nozzle clogging may occur.

Colorant particles (composite pigment particles) obtained by coating the inorganic particles with an organic pigment or carbon black have a strong tendency to show acidity when kneaded and dispersed in water together with an anionic dispersant. The surface of the composite pigment particles dispersed in a medium such as water is negatively charged because it is encapsulated in an anionic dispersant. However, since the entire ink is acidic, the medium itself has a positive charge. It is in a state in which the negative charge on the particle surface is easily neutralized. In this state, the dispersed particles agglomerate and cause a discharge failure. Therefore, it is preferable to stabilize the dispersion state by adding a pH adjuster to keep the dispersion and to stabilize the discharge.
The pH of the aqueous recording ink is preferably 7-11. When the pH exceeds 11, the amount of the material for the ink jet head and the ink supply unit to be melted increases, and problems such as ink deterioration, leakage, and ejection failure occur.
It is more preferable to add the pH adjuster when kneading and dispersing the pigment in water together with the dispersant than together with additives such as a kneading and dispersing machine, a wetting agent, and a penetrating agent. This is because the dispersion may be destroyed by addition depending on the pH adjusting agent.

Examples of the pH adjuster include alcohol amines, alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, and alkali metal carbonates.
Examples of alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.
Examples of the ammonium hydroxide include ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, and the like.
Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

Examples of antiseptic / antifungal agents include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, sodium pentachlorophenol and the like.
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

<Cartridge>
The pretreatment liquid used in the present invention may be accommodated in a container to form a cartridge. The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, an ink bag formed of a plastic container, an aluminum laminate film, a resin film, etc. The thing which has is mentioned.
A specific example is the same structure as the ink cartridge shown in FIG.
FIG. 4 is an example of an ink cartridge.
The ink is filled into the ink bag 241 from the ink inlet 242 and exhausted, and then the ink inlet 242 is closed by fusion. In use, ink is supplied to the apparatus by inserting a needle of the apparatus main body into the ink discharge port 243 made of a rubber member. The ink bag 241 is formed of a packaging member such as a non-permeable aluminum laminate film. The ink bag 241 is usually housed in a plastic cartridge case 244, and is used as an ink cartridge 240 that is detachably mounted on various ink jet recording apparatuses.
Further, if a pretreatment liquid is put in the ink cartridge 240 instead of the ink and used as a cartridge for the pretreatment liquid, it can be used by being detachably mounted on various ink jet recording apparatuses in the same manner as the ink cartridge.

<Inkjet recording apparatus>
Figure 1 shows an example schematic view of Lee inkjet recording apparatus (side view) as reference drawing.
The ink jet recording apparatus 101 includes a printing unit P having a head unit 110, a paper discharge mechanism, and the like, an upper paper feeding unit Q provided below the printing unit, and a lower paper feeding provided below the upper paper feeding unit. And a coating mechanism (pretreatment means) S and a pretreatment liquid storage tank (storage means) 140 attached to the lower sheet feeding section R. In addition, the inkjet recording apparatus 101 includes a waste liquid tank 109 that collects waste liquid discharged after maintenance, an operation panel 106 that can operate the apparatus and display the apparatus state, the entire apparatus, and a control unit that controls and controls each part (FIG. (Not shown).
When the pre-processing is performed by the coating mechanism S, the recording medium 114 (for example, printing paper) is fed from the lower sheet feeding unit R, and the recording medium 114 that has been pre-processed passes through the upper sheet feeding unit Q. Then, it is sent to the printing section P and printing processing is performed. On the other hand, when the pre-processing is not performed by the coating mechanism S, the recording medium 114 is fed from the upper sheet feeding unit Q, and the recording medium 114 is sent to the printing unit P to perform the printing process. ing.
The printing unit P includes head units 110K, 110C, 110M, and 110Y (ejection means) that integrate ink jet heads that eject ink, and maintenance units 111K, 111C, 111M that perform head maintenance corresponding to the head units. 111Y, ink cartridges 107K, 107C, 107M, 107Y for supplying ink, sub ink tanks 108K, 108C, 108M, 108Y for storing a part of ink from the cartridge and supplying ink with an appropriate pressure to the head, and paper discharge And a mechanism T.

The paper discharge mechanism T includes a conveyance belt 113 that sucks and conveys the recording medium 114, conveyance rollers 119 and 121 around which the conveyance belt 113 is wound, a tension roller 115 that controls the conveyance belt 113 to maintain an appropriate tension, A platen 124 for maintaining appropriate flatness of the belt 113, a charging roller 116 for applying electrostatic charging to the conveyance belt 113 for attracting the recording medium 114, a discharge roller 117 for pressing the recording medium, and a discharged recording medium 114 The paper discharge tray 104 stores the stock.
Each of the upper sheet feeding unit Q and the lower sheet feeding unit R includes a sheet feeding tray 103 that stocks the recording medium 114 to be printed, and a separation pad 112 that feeds the recording medium 114 one by one from the sheet feeding tray. The part Q includes a counter roller 123 that reliably attracts the recording medium 114 that has been fed to the conveyor belt 113, and a manual feed tray 105 that is used when paper is manually fed. The recording medium 114 stocked in the lower paper feed section R has a surface treated beforehand with a polyvalent metal salt.
The nozzle rows of each head unit 110 are arranged so as to be orthogonal to the conveyance direction of the recording medium 114, and form a nozzle row that is longer than the recording area. The recording medium 114 is separated from the paper feed tray 103 one by one by the separation pad 112, and is fixed on the conveying belt 113 by being in close contact with the conveying belt 113 by the counter roller 123, and recorded when passing under the head unit 110. By ejecting droplets onto the medium 114, patterning can be performed on the recording medium 114 with droplets at a high speed, and the recording medium 114 is separated from the transport belt 113 by a separation claw (not shown), and is supported by the charging roller 116 and the sheet discharge roller 117. As a result, the recorded matter is discharged to the discharge tray 104.

The coating mechanism S employs roller coating. It is stored pretreatment liquid in the pretreatment liquid storage tank 140. The pretreatment liquid 135 supplied from the pretreatment liquid storage tank 140 to the pretreatment tank 130 via a flow path (not shown) is bubbled by an air blowing mechanism (not shown), and then pumped up by a pumping roller 137. Pumped up on the roller surface and transferred to the film pressure control roller 138. Subsequently, the pretreatment liquid transferred to the application roller 136 is transferred and applied to the recording medium 114 passing between the application roller 136 and the application counter roller 139.
The application amount of the pretreatment liquid transferred to the application roller 136 is performed by controlling the nip thickness between the application roller 136 and the film pressure control roller 138. When it is not desired to apply the pretreatment liquid, the movable blade 134 can be pressed against the application roller 136 so that the pretreatment liquid does not remain on the application roller 136 and the pretreatment liquid on the surface of the application roller can be scraped off. As a result, it is possible to prevent functional troubles such as thickening due to drying of the pretreatment liquid, adhesion to the application counter roller 139, and uneven application, which occur because the pretreatment liquid remains on the application roller 136. . Note that the liquid pretreatment liquid may be applied without providing the air blowing mechanism.

It will now be described implementation form of the ink jet recording apparatus of the present invention. In the ink jet recording apparatuses of the first and second embodiments, a first pretreatment liquid containing a polyvalent metal salt and an acid and a second pretreatment liquid containing sodium alginate are applied (discharged) to the recording medium. After that, recording is performed with ink.
The ink jet recording apparatus of the first embodiment shown in FIG. 2 has substantially the same configuration as that of the ink jet recording apparatus of FIG. 1 , but instead of the pretreatment liquid storage tank 140, a first ink containing a polyvalent metal salt and an acid. A first storage tank (not shown) for storing one pretreatment liquid and a second storage tank (not shown) for storing a second pretreatment liquid containing sodium alginate are provided. Further, unlike the application mechanism S of FIG. 1 , the application mechanism S faces the first storage tank over the large-diameter application roller 136, the small-diameter counter roller 139 that is in rolling contact with the application roller 136, and the application roller 136. The first pretreatment liquid dropping mechanism U having a dropping nozzle for dripping the first pretreatment liquid stored in the coating roller 136 onto the surface of the application roller 136 and the second pretreatment liquid stored in the second storage tank are applied. And a second pretreatment droplet dropping mechanism V having a dropping nozzle for dropping on the surface of the roller 136. Each dropping nozzle is arranged in the axial direction of the application roller 136. The first pretreatment liquid dropped from the dropping mechanism U and the second pretreatment liquid dropped from the dropping mechanism V are mixed at the nip portion between the coating roller 136 and the counter roller 139 to become a pretreatment liquid. The pretreatment liquid is applied to the recording medium 114 by the application roller 136. The movable blade 134 has the same function as the movable blade 134 in FIG. 1 , and a receiving member 141 that receives the pretreatment liquid scraped off by the movable blade 134 is provided below the movable blade 134.
In the ink jet recording apparatus of the first embodiment, the first pretreatment liquid and the second pretreatment liquid are stored separately in a first storage tank and a second storage tank, and the pretreatment is performed on the surface of the recording medium. Since the first pretreatment liquid and the second pretreatment liquid are mixed by the application roller 136 and the counter roller 139 immediately before the application, the polyvalent metal salt and acid of the first pretreatment liquid and the second pretreatment liquid are mixed. It is possible to prevent sodium alginate from reacting in advance and gelling or precipitating.

The ink jet recording apparatus of the second embodiment shown in FIG. 3 has substantially the same configuration as the ink jet recording apparatus of FIG. 1 , but instead of the coating mechanism S and the pretreatment liquid storage tank 140, a polyvalent metal salt and A first storage tank (not shown) for storing a first pretreatment liquid containing acid, a second storage tank (not shown) for storing a second pretreatment liquid containing sodium alginate, and a first storage A first pretreatment liquid spray mechanism W having a spray nozzle for spraying the first pretreatment liquid stored in the tank onto the surface of the recording medium 114, and a second pretreatment stored in the second storage tank. A second pretreatment liquid spray mechanism X having a spray nozzle for spraying the liquid onto the surface of the recording medium 114, and a transport mechanism (not shown) for transporting the recording medium 114 to each spray nozzle of the spray mechanism W and the spray mechanism X. )). The first pretreatment liquid and the second pretreatment liquid are sequentially sprayed from the spray mechanism W and the spray mechanism X onto the surface of the recording medium 114 transported by the transport mechanism. Of course, the second pretreatment liquid and the first pretreatment liquid may be sprayed in this order, and the first pretreatment liquid and the second pretreatment liquid may be sprayed simultaneously on each part. .
In the ink jet recording apparatus according to the second embodiment, the first pretreatment liquid and the second pretreatment liquid are separately used to perform the pretreatment on the surface of the recording medium. It is possible to prevent the valent metal salt and acid and the sodium alginate of the second pretreatment liquid from reacting in advance and gelling or precipitating.

In addition to the above roller application, the pretreatment liquid may be spray applied by an ink jet method. For example, a pretreatment liquid can be filled in a head similar to 110K and ejected onto the recording medium 114 in the same manner as ink, and the ejection amount and ejection position can be controlled with high accuracy and ease.
Regardless of which method is used, the pretreatment liquid can be applied in an arbitrary amount at an arbitrary position.

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

Reference Example 1-2, Example 3-4, Comparative Examples 1-4
Pretreatment liquids used in the examples , reference examples, and comparative examples were prepared using the materials having the formulations shown in Table 1. Immediate Chi, a first pretreatment solution containing at least one of a polyvalent metal salt and acid, the second pre-treatment solution was made by adjusting divided into the (Comparative Examples 2 to 4 In the first prior containing alginate Na Treatment liquid only).
Next, after blowing air into each pretreatment liquid and bubbling, in Comparative Examples 2 to 4, using a wire bar (winding diameter: 0.02 mm) manufactured by Kobayashi Seisakusho, a recording medium (manufactured by Ricoh Company: My Recycle) Paper GP) was evenly applied. In Reference Examples 1 and 2 and Examples 3 to 4, the ink jet recording apparatus having the configuration according to the first embodiment (made by Ricoh Co., Ltd .: a part of IPSIO GX5000) is used for the first front containing acid. Treatment liquid ( Reference Example 1), first pretreatment liquid containing a polyvalent metal salt ( Reference Example 2), first pretreatment liquid containing a polyvalent metal salt and an acid (Examples 3 to 4), and alginic acid A recording medium (manufactured by Ricoh: My Recycle Paper GP) was pretreated using a second pretreatment liquid containing sodium. The application amounts of the first pretreatment liquid and the second pretreatment liquid were 80 to 100 mg / A4 size paper, respectively.
Next, an aqueous recording ink was ejected onto the pretreated recording medium at a printing speed of 30 rpm according to a chart in which 5% of the total area of the A4 size paper was a solid image by the inkjet recording apparatus to obtain a printing sample. In Reference Examples 1-2 and Example 3 , a GX cartridge (Cyan GC21CS) manufactured by Ricoh Company was used as the aqueous recording ink. Moreover, in Example 4, in order to see the influence of carboxyl group-containing resin, what was made on the basis of the GC21CS was used.
The materials shown in Table 1 are as follows, and “%” in the table is “% by weight”. The same applies to Tables 2 to 4 described later (for Table 1, the weight when the total weight of the first pretreatment liquid and the second pretreatment liquid is 100).
· CaCl _2: manufactured by Kanto Chemical Co., Inc. Calcium chloride dihydrate Alginate Na: Kimica Corp. ULV-L3G
Lactic acid: manufactured by Kanto Chemical Co., Ltd. Fluorosurfactant: Zonyl FS-300 manufactured by Dupon

Examples 5-12, Reference Examples 13-16 , Comparative Examples 5-8
Using the materials having the formulations shown in Table 2, four types of second pretreatment liquids F-1, F-2, F-3, and F-4 containing sodium alginate were prepared.
On the other hand, first pretreatment liquids containing polyvalent metal salts and acids of Examples , Reference Examples and Comparative Examples were prepared using the materials having the formulations shown in Tables 3 and 4.
Next, the recording medium was pretreated in the same manner as in Example 1 except that the first pretreatment liquid and the second pretreatment liquid were used in combination as shown in Tables 3 and 4, followed by aqueous treatment. A recording sample was obtained by discharging recording ink.
The data such as image density in Table 2 are reference materials for a print sample prepared by pre-processing a recording medium in the same manner as in Comparative Example 2.

About each said printing sample, various characteristics were evaluated with the following method. The results are shown in Tables 1-5.
"Image density"
The solid portion of the print sample was measured with a spectral color density system (939) manufactured by X-Rite. Larger numbers are better.
"Transfer density"
The solid part of the print sample is affixed to a clock meter manufactured by Toyo Seiki Seisakusho and rubbed, and the transfer density of ink onto the cloth after rubbing is measured using a spectroscopic color densitometer (939) manufactured by X-Rite. Measured with The smaller the transfer density, the better the image fixability.
“Dot diameter (μm)”
For the print sample, an image was measured with a digital microscope manufactured by Keyence Corporation: VHX-200, and then an average value of N (= number of samples) = 20 was calculated by dot diameter analysis software. A larger dot diameter is better.

As can be seen from Table 1 above, the image density and the dot diameter are higher in Comparative Example 1 in which pretreatment is not performed and in Comparative Example 3 in which pretreatment is performed with only acid than in Reference Example 1 in which sodium alginate and acid are pretreated. Improved. Further, compared to Comparative Example 1 in which pretreatment was not performed and Comparative Example 2 in which pretreatment liquid was pretreated with only a polyvalent metal salt, Reference Example 2 in which pretreatment liquid was pretreated with sodium alginate and polyvalent metal salt was used. Improved. Further, in Example 3 was used in the pretreatment of the tripartite sodium alginate and polyvalent metal salt and acid, the co-image density and dot diameter than Reference Examples 1 and 2 is improved, improving the transfer density (decrease) did. Further, Example 4 was a case where printing was performed using an aqueous recording ink not containing a carboxyl group-containing resin, and the same result as in Reference Example 1 was obtained.
In addition, as can be seen from Tables 3 and 4 above, compared with Comparative Examples 5 to 8 using a pretreatment liquid containing a polyvalent metal salt and an acid, the three of sodium alginate, polyvalent metal salt and acid In Examples 5 to 12 and Reference Examples 13 to 16 used in the processing, the image density and the dot diameter were improved. However, the transfer density was improved in Examples 5 to 12, but deteriorated in Reference Examples 13 to 16. That is, from the viewpoint of improving the transfer density, the amount of sodium alginate added in the pretreatment liquid is preferably 5% by weight or less.
In addition, although the case where printing speed was 30 rpm was shown in the Example, this invention is applicable also to the high-speed printing of 100 rpm or more.

P Printing section Q Upper sheet feeding section R Lower sheet feeding section S Coating mechanism T Discharging mechanism U First pretreatment droplet dropping mechanism V Second pretreatment droplet dropping mechanism W First pretreatment liquid spraying mechanism X Second Pretreatment liquid spray mechanism 101 Inkjet recording device 103 Paper feed tray 104 Paper discharge tray 105 Manual feed tray 106 Operation panel 107K Ink cartridge 107C Ink cartridge 107M Ink cartridge 107Y Ink cartridge 108K Sub ink tank 108C Sub ink tank 108M Sub ink tank 108Y Sub Ink tank 109 Waste liquid tank 110K Head unit 110C Head unit 110M Head unit 110Y Head unit 111K Maintenance unit 111C Maintenance unit 111M Maintenance unit G 111Y Maintenance unit 112 Separation pad 113 Conveying belt 114 Recording medium 115 Tension roller 116 Charging roller 117 Discharge roller 118 Platen roller 119 Conveying roller 120 Suction fan 121 Conveying roller 122 Separating pad 123 Counter roller 124 Platen 130 Pretreatment tank 134 Movable blade 135 Pretreatment liquid 136 Application roller 137 Pumping roller 138 Film pressure control roller 139 Application counter roller 140 Pretreatment liquid storage tank 141 Pretreatment liquid receiving member 240 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge case

JP 2005-154767 A

Claims (3)

In the ink jet recording method including a step of processing a recording medium prior to recording and a step of recording with an aqueous recording ink, the step of processing the recording medium includes a first pretreatment including a polyvalent metal salt and an acid. An ink jet recording method comprising a step of treating a recording medium with a liquid and a second pretreatment liquid containing sodium alginate at a concentration of 5% by weight or less . An aqueous recording ink discharge means, a first pretreatment liquid storage means containing a polyvalent metal salt and an acid, and a second pretreatment liquid storage means containing sodium alginate at a concentration of 5% by weight or less, An ink jet recording apparatus comprising: pretreatment means for treating a surface of a recording medium with a first pretreatment liquid and a second pretreatment liquid before discharging the aqueous recording ink by the discharge means. A pretreatment liquid set for treating the surface of an aqueous recording ink before recording on a recording medium, the first pretreatment liquid containing a polyvalent metal salt and an acid, and 5 wt% or less And a second pretreatment solution containing sodium alginate at a concentration of .

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