JP5509585B2 - Pretreatment method for recording medium, pretreatment liquid, cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a pretreatment method, a pretreatment liquid for treating a surface of a recording medium before recording on a recording medium using an aqueous recording ink, a cartridge and an image forming apparatus using the same.

In the case of a combination of a conventional acid-containing pretreatment liquid and an ink containing a colorant included in a carboxyl group-containing resin, pigment aggregation occurs on the recording medium due to the acid and carboxyl group, resulting in high density and high image quality. Although it is possible to obtain an image, the agglomerated pigment cannot be fixed, and especially during high-speed conveyance such as a line engine system (for example, during high-speed printing at 100 rpm or higher), transfer stains to a conveyance roller or the like Will occur a lot.
For example, Patent Document 1 describes that a component (chitosan and a non-volatile organic acid) that aggregates the colorant is contained in the pretreatment liquid. However, although the image density is improved by aggregating the colorant, the filling rate is reduced due to the dot reduction on the recording medium, and the fixing property is deteriorated due to the colorant being stacked in the height direction. .
On the other hand, Patent Document 2 contains an ink composition containing colored resin particles in which a resin having a carboxyl group encapsulates a dye or pigment and a polymer having an oxazoline group for the purpose of high image quality and high abrasion resistance. It is described that a temporary image is formed by mixing a reaction solution to be heated on a recording medium, and the resultant is heated.
However, since the crosslinking reaction rate by the carboxyl group and the oxazoline group is not so fast, the fixability of the image immediately after printing is insufficient. For this reason, as in the case of the acid described above, a large amount of transfer contamination occurs on the conveyance roller or the like.

JP 2005-248133 A JP 2003-072220 A

  The present invention provides a pretreatment method and a pretreatment liquid capable of improving the fixability of an image and recording a high image density and high image quality when recording on a recording medium using an aqueous recording ink. Another object is to provide a cartridge and an image forming apparatus using the same.

The above problems are solved by the following inventions 1) to 11 ).
1) Before discharging an aqueous recording ink containing a carboxyl group-containing resin , an acid and a water-soluble oxazoline group-containing polymer are mixed in an amount of 0.01% of the total amount of oxazoline groups in the water-soluble oxazoline group-containing polymer with respect to 1 mol of acid. A pretreatment method comprising treating a surface of a recording medium using a ratio of ˜0.5 mol .
2 ) The recording medium surface is treated with a mixed solution of an acid and a water-soluble oxazoline group-containing polymer, and the acid and the water-soluble oxazoline group-containing polymer are mixed immediately before the recording medium surface is pretreated. The pre-processing method as described in 1) characterized by the above.
3 ) The pretreatment method according to 1), wherein the surface of the recording medium is treated by separately using an acid and a water-soluble oxazoline group-containing polymer.
4 ) The pretreatment method according to any one of 1) to 3) , wherein the treatment is performed using a pretreatment liquid containing a surfactant in addition to the acid and the water-soluble oxazoline group-containing polymer.
5 ) A pretreatment liquid for treating the surface of an aqueous recording ink containing a carboxyl group-containing resin before recording on a recording medium, wherein the acid and the water-soluble oxazoline group-containing polymer are treated with a water-soluble oxazoline. A pretreatment liquid comprising a total amount of oxazoline groups of a group-containing polymer in a ratio of 0.01 to 0.5 mol with respect to 1 mol of an acid .
6 ) The pretreatment liquid according to 5) , which contains a surfactant in addition to the acid and the water-soluble oxazoline group-containing polymer.
7 ) A cartridge comprising the pretreatment liquid according to 5) or 6) contained in a container.
8 ) Aqueous recording ink discharge means containing a carboxyl group-containing resin, a storage means for storing an acid and a water-soluble oxazoline group-containing polymer, and an acid and a water-soluble oxazoline group before discharging the aqueous recording ink by the discharge means And a pretreatment means for treating the surface of the recording medium using the polymer containing the total amount of oxazoline groups of the water-soluble oxazoline group-containing polymer in a ratio of 0.01 to 0.5 mol with respect to 1 mol of the acid. An image forming apparatus.
9 ) The storage means includes an acid storage means for storing an acid solution containing an acid and a polymer storage means for storing a polymer solution containing a water-soluble oxazoline group-containing polymer, and further, the acid solution and the polymer solution are mixed. 8) The image forming apparatus according to 8) , further comprising a mixing unit that serves as a pretreatment liquid, wherein the pretreatment unit pretreats the surface of the recording medium with the pretreatment liquid.
10 ) The storage means has an acid storage means for storing an acid solution containing an acid and a polymer storage means for storing a polymer solution containing a water-soluble oxazoline group-containing polymer, and the pretreatment means is recorded by an acid solution. 8. The image formation according to 8) , comprising acid pretreatment means for pretreating the surface of the medium and polymer pretreatment means for pretreating the surface of the recording medium with a polymer solution. apparatus.

Hereinafter, the present invention will be described in detail.
<About pretreatment method and pretreatment liquid>
The pretreatment method of the present invention is characterized in that a recording medium surface is treated with an acid and a water-soluble oxazoline group-containing polymer before discharging a water-based recording ink, and a crosslinking reaction is caused between the two. As a result, the fixability of the image can be improved. However, in order to prevent the crosslinking reaction from proceeding and solidifying before use as a pretreatment liquid containing an acid and a water-soluble oxazoline group-containing polymer, it is preferable to adjust the addition ratio of both. In order to reliably prevent unnecessary cross-linking reaction, the both are mixed immediately before pre-treating the recording medium surface and treated with the pre-treatment liquid, or both are used separately to The method of processing is preferred. In the case of these methods, the acid and the water-soluble oxazoline group-containing polymer may be used as they are or in a solution. Moreover, when using both separately, the processing order of both may be first and may be simultaneous. After the treatment, the water-based recording ink is quickly ejected onto it.

Further, when processing with the pretreatment liquid, the pretreatment liquid is applied in order to reduce the surface tension of the pretreatment liquid or when the pretreatment liquid is applied to the surface of the recording medium in a foamed state (details will be described later). In order to make it foam, it is preferable to add a surfactant. In the case of using a surfactant, when the acid and the water-soluble oxazoline group-containing polymer are mixed just before the surface of the recording medium is pretreated, the surfactant is added to one or both, or the surfactant The agent, the acid and the water-soluble oxazoline group-containing polymer are mixed at the same time.
In addition, as a configuration for treating the surface of the recording medium using an acid and a water-soluble oxazoline group-containing polymer, for example, a configuration in which a solution containing at least one of an acid and a water-soluble oxazoline group-containing polymer is coated on the surface of the recording medium by a coating roller. A configuration in which the solution is discharged from the ink jet head onto the surface of the recording medium, and a configuration in which the solution is sprayed onto the surface of the recording medium from a spray nozzle can be exemplified.

The acid used in the present invention is preferably one having a carboxyl group, particularly an organic acid. 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 lies in a crosslinking reaction with the water-soluble oxazoline group-containing polymer, thereby contributing to improvement in image fixability. Further, when the aqueous recording ink contains a carboxyl group-containing resin, it contributes to high image density and high image quality due to the aggregating function of the pigment on the recording medium by reaction with the resin.

Amount of acid added, and 1mol or more with respect to the total amount 0.5mol oxazoline group of water-soluble oxazoline group-containing polymer. This is to ensure that all acids are not consumed in the first crosslinking reaction with the water-soluble oxazoline group-containing polymer. When all the acid is consumed, the subsequent reaction with the carboxyl group-containing resin does not occur.
However, if the amount of the acid is too large, since the agglomeration effect of the pigment by reaction with mosquito carboxyl group-containing resin is increased undesirably. As shown in Table 1-2, which will be described later, when the amount of acid added is increased, the aggregation of the pigment proceeds, and the dot diameter on the recording medium becomes smaller. This means that the spread of the dots is reduced. In particular, if the filling of the solid portion is insufficient, there is a problem that 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 within a range that does not cause image defects.

As the water-soluble oxazoline group-containing polymer of the present invention, for example, an acrylic-styrene resin, an acrylic resin, a styrene resin, or an acrylonitrile-styrene resin can be used.
The water-soluble oxazoline group-containing polymer is available as a commercial product, for example, K-2000 series (acrylic-styrene resin), WS series (acrylic resin), RPS series (styrene resin) manufactured by Nippon Shokubai Co., Ltd. RAS series (acrylonitrile-styrene resin) and the like can be mentioned.
Further, fine particles having a water-soluble oxazoline group-containing polymer adsorbed on the surface may be used, and are commercially available. For example, as organic fine particles, ME series by Soken Chemical Co., Ltd., Jurimer MB series by Nippon Pure Chemicals, Tospearl series by Toshiba Silicone, Microgel series by Nippon Paint, Pullon series by Asahi Glass Examples of the inorganic fine particles include titania release manufactured by Idemitsu Kosan Co., Ltd. and aluminum oxide C manufactured by Nippon Aerosil Co., Ltd.

The total amount of the oxazoline group of the water-soluble oxazoline group-containing polymer to acid 1 mol, although less 0.5 mol, less favorable preferable 0.25 mol. This, when processing a recording medium surface by using a pretreatment liquid to prevent the pretreatment liquid is solidified prior to application of the recording medium by a crosslinking reaction,及Beauty mosquito carboxyl group-containing resin and a water-soluble This is to prevent consumption of all the acid by the crosslinking reaction with the oxazoline group-containing polymer. In addition, as shown in FIG. 3 to be described later, if the total amount of oxazoline groups is 0.5 mol or less with respect to 1 mol of the acid, the fixability of the image on the recording medium tends to be better than when not added. It is. As shown in FIG. 4, the fixability is improved when the acid addition ratio is decreased. As the acid addition ratio is decreased, the dot diameter on the recording medium is increased, that is, the pigment is excessively aggregated. It is thought that this is because there is not. Further, when the total amount of oxazoline groups is more than 0.01 mol with respect to 1 mol of the acid, the effect of improving the fixability of the image tends to increase.

As described above, when the surface of the recording medium is treated with the pretreatment liquid, it is preferable to add a surfactant, which makes it possible to apply the pretreatment liquid in the form of foam on the surface of the recording medium. .
That is, if an excessive amount of pretreatment liquid is applied to the recording medium, the cost increases, and depending on the type of solvent in the pretreatment liquid, problems such as curling of the recording medium may occur. It is preferable to reduce the coating amount of the liquid as much as possible. However, if the thickness of the liquid pretreatment liquid on the surface of the application roller is extremely thin, the contact between the application roller surface and the recording medium having irregularities is not good. There will be places where you can't. Therefore, it is preferable to apply the pretreatment liquid to the recording medium after foaming it in advance.
There is no restriction | limiting in particular in surfactant, A well-known thing can be used. For example, a silicone-based surfactant, a fluorine-based surfactant, an acetylene glycol-based surfactant, and the like may be used, and 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 as a solvent to a solution or a pretreatment liquid containing an acid and a water-soluble oxazoline group-containing polymer. 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.
Examples of volatile water-soluble solvents include methanol and ethanol.

The aqueous recording ink according to the present invention 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 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. And IPPR122 composite materials, and the like. These have a small primary particle size and can be suitably used.

For example, when inorganic particles having a primary particle size of 20 nm are coated with an equal amount of organic pigment, the 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 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 primary particle size is less than 5 nm, the ink may thicken during long-term storage of the ink or the colorant particles may aggregate, and if it exceeds 100 nm, when printing the ink on a medium such as paper or film, There may be a printed matter in which the saturation and lightness of the printing section are lowered. 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 according to the present invention uses water as a solvent, but 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.

In addition to the water-soluble organic solvent, the water-based recording ink according to the present invention can be used in combination with other water-soluble organic solvents such as saccharides and derivatives thereof as necessary. 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 according to the present invention 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-mentioned components, a known penetrant, polymer particles, pH adjuster, antiseptic / antifungal agent, rust preventive agent and the like may be added to the water-based recording ink according to the present invention, if necessary. it can.
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 cartridge of the present invention contains the pretreatment liquid of the present invention in a container, and has other members and the like appropriately selected as necessary.
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, or the like Etc. which have etc. are mentioned.
As a specific example, for example, one having the same structure as the ink cartridge shown in FIG.

Next, the ink cartridge will be described with reference to FIG.
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 attached to various image forming 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 attached to various image forming apparatuses in the same manner as the ink cartridge.

<Image forming apparatus>
FIG. 1 shows a schematic diagram (side explanatory view) of an example (first embodiment) of an image forming apparatus according to the present invention.
The image forming apparatus 101 includes a printing unit P having a head unit 110 and a paper discharge mechanism, an upper sheet feeding unit Q provided below the printing unit, and a lower sheet feeding unit provided below the upper sheet 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 image forming 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 state of the apparatus, 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 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. After the pretreatment liquid 135 supplied from the pretreatment liquid storage tank 140 to the pretreatment tank 130 through a flow path (not shown) is bubbled by an air blowing mechanism (not shown), a roller is drawn up by a pumping roller 137. It is pumped up to the 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 that passes 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.

Next, another embodiment of the image forming apparatus will be described.
The image forming apparatus of the second embodiment shown in FIG. 5 has substantially the same configuration as the image forming apparatus of the first embodiment, but stores an acid solution containing an acid instead of the pretreatment liquid storage tank 140. An acid storage tank (acid storage means, not shown) and a polymer storage tank (polymer storage means, not shown) for storing a polymer solution containing a water-soluble oxazoline group-containing polymer. An acid solution is supplied from the acid storage tank to the pretreatment tank 130 (mixing means), and a polymer solution is supplied from the polymer storage tank so that both solutions are mixed in the pretreatment tank 130. The coating mechanism S has substantially the same configuration as the coating mechanism S of the first embodiment, but the film thickness control roller 138 is omitted. In the image forming apparatus of the second embodiment, the acid solution and the polymer solution are stored separately in the acid storage tank and the polymer storage tank, and the acid is stored in the pretreatment tank 130 immediately before the pretreatment is performed on the surface of the recording medium. Since the solution and the polymer solution are mixed, it is possible to prevent the acid and the water-soluble oxazoline group-containing polymer from excessively causing a crosslinking reaction in advance.

  The image forming apparatus according to the third embodiment shown in FIG. 6 has substantially the same configuration as the image forming apparatus according to the first embodiment, but stores an acid solution containing an acid instead of the pretreatment liquid storage tank 140. An acid storage tank (acid storage means, not shown) and a polymer storage tank (polymer storage means, not shown) for storing a polymer solution containing a water-soluble oxazoline group-containing polymer. Furthermore, unlike the application mechanism S of the first embodiment, the application mechanism S faces the upper side of 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 to store the acid. An acid solution dropping mechanism U having a dropping nozzle for dropping the acid solution stored in the tank onto the surface of the coating roller 136, and a polymer having a dropping nozzle for dropping the polymer solution stored in the polymer storage tank onto the surface of the coating roller 136 And a solution dropping mechanism V. Each dropping nozzle is arranged in the axial direction of the application roller 136. Then, the acid solution dropped from the acid solution dropping mechanism U and the polymer solution dropped from the polymer solution dropping mechanism V are mixed at the nip portion between the coating roller 136 and the counter roller 139 to become a pretreatment liquid, and the pretreatment is performed. The 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 of the first embodiment, and a receiving member 141 that receives the pretreatment liquid scraped off by the movable blade 134 is provided below the movable blade 134. Yes. In the image forming apparatus according to the third embodiment, the acid solution and the polymer solution are stored separately in an acid storage tank and a polymer storage tank, and the coating roller 136 and the counter roller 139 immediately before the recording medium surface is pretreated. Since the acid solution and the polymer solution are mixed, it is possible to prevent the acid and the water-soluble oxazoline group-containing polymer from excessively causing a crosslinking reaction in advance.

  The image forming apparatus of the fourth embodiment shown in FIG. 7 has substantially the same configuration as the image forming apparatus of the first embodiment, but includes an acid instead of the coating mechanism S and the pretreatment liquid storage tank 140. An acid storage tank (acid storage means, not shown) for storing an acid solution, a polymer storage tank (polymer storage means, not shown) for storing a polymer solution containing a water-soluble oxazoline group-containing polymer, and an acid storage tank An acid solution spray mechanism W (acid pretreatment means) having a spray nozzle for spraying the stored acid solution onto the surface of the recording medium 114 and the polymer solution stored in the polymer storage tank are sprayed onto the surface of the recording medium 114. The recording medium 114 is carried to each of the spray nozzles of the polymer solution spray mechanism X (polymer pretreatment means) having the spray nozzle and the acid solution spray mechanism W and the polymer solution spray mechanism X. And a transport mechanism (not shown) to. The polymer solution and the acid solution are sequentially sprayed from the polymer solution spray mechanism X and the acid solution spray mechanism W onto the surface of the recording medium 114 transported by the transport mechanism. Needless to say, the acid solution and the polymer solution may be sprayed in this order, or the acid solution and the polymer solution may be sprayed simultaneously on each portion. In the image forming apparatus according to the fourth embodiment, the acid and the water-soluble oxazoline group-containing polymer are separately used and the pretreatment is performed on the surface of the recording medium. It is possible to prevent a crosslinking reaction from occurring.

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 way 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.

  According to the present invention, when recording on a recording medium using an aqueous recording ink, the pretreatment method can improve the fixability of an image, and further obtain a high image density and high image quality. A treatment liquid, a cartridge and an image forming apparatus using the treatment liquid can be provided.

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.

Examples 1 7 and Reference Example 8, Comparative Example 1-9
After air was blown into the pretreatment liquids of the Examples , Reference Examples, and Comparative Examples prepared by mixing the materials having the formulations shown in Table 1-1 and Table 1-2, the wire bar (manufactured by Kobayashi Manufacturing Co., Ltd.) Using a winding diameter of 0.02 mm, it was uniformly applied to a recording medium (Ricoh dry PPC paper My Paper).
Next, an aqueous recording ink was ejected onto the recording medium with an image forming apparatus (IPSIO GX5000 manufactured by Ricoh Co., Ltd.) according to a predetermined image at a printing speed of 30 rpm to obtain a printing sample. For the water-based recording ink, GX cartridge cyan GC21CS manufactured by Ricoh Company was used. This ink contains a copolymer of (meth) acrylic acid ester and styrene.
In addition, the numerical value of the material column in Table 1-1 and Table 1-2 showed weight%, and the following were used for each material.
Ethanol: manufactured by Kanto Chemical Co., Ltd. Lactic acid: manufactured by Wako Pure Chemical Industries, Ltd. Fluorosurfactant: Surflon S-111 manufactured by Asahi Glass Co., Ltd.
Water-soluble oxazoline group-containing polymer 1: EPOCROSS K-2030E manufactured by Nippon Shokubai Co., Ltd.
-Water-soluble oxazoline group-containing polymer 2: Nippon Shokubai Epocross WS-700

About each said printing sample, various characteristics were evaluated with the following method.
The evaluation results are shown in Table 1-1 and Table 1-2. FIG. 3 shows the relationship between the number of moles of the oxazoline group and the transfer concentration with respect to 1 mol of acid, and FIG. 4 shows the relationship between the number of moles of the oxazoline group with respect to 1 mol of acid and the dot diameter. 3, both of FIG. 4, in order from the left, examples 1,3,4,5,6,7, in which reference example 8 and mol number is plotted with the reference example in the case of 1.36.

[Image density]
The solid portion of the print sample was measured with a spectrocolorimetric densitometer (939) manufactured by X-Rite.
Larger numbers are better.
[Transfer density (fixability)]
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 spectrophotometric densitometer (939) manufactured by X-Rite. Measured with The smaller the transfer density, the better the image fixability.
[Dot diameter (μm)]
With respect to the print sample, an image was taken with a digital microscope VHX-200 manufactured by Keyence Corporation, and then an average value of N (number of samples) = 20 was calculated by dot diameter analysis software. A larger dot diameter is better.

Examples 10 to 14, Reference Example 15
[Solidification test]
The same lactic acid and water-soluble oxazoline group-containing polymer 2 used in Example 1 were mixed, and the mixed solution was placed on a slide glass and allowed to stand overnight, and then the slide glass was tilted to determine the fluidity of the mixed solution. did. The evaluation criteria for the solidification level are as follows. The results are shown in Table 2. In addition, the numerical value of the material column in Table 2 is weight%.
○: Fluidity
△: Some fluidity is seen
×: No fluidity

As can be seen from Table 1-1 and Table 1-2, Examples 1 to 7 in which the surface of the recording medium was pretreated with an acid and a water-soluble oxazoline group-containing polymer when the carboxyl group-containing resin was included in the ink were used. Compared with Comparative Example 1 in which no pretreatment was performed and Comparative Examples 2 to 9 in which only one of an acid and a water-soluble oxazoline group-containing polymer was used, in Examples 1 to 7 , the image density and transfer While satisfactory results were obtained for both the density and the dot diameter, in Comparative Examples 1 to 9, at least one of the image density, the transfer density, and the dot diameter was inferior. That is, when only acid was used (for example, Comparative Example 2), the transfer density was high and the dot diameter was small. On the other hand, when only the water-soluble oxazoline group-containing polymer was used (for example, Comparative Example 8), the image density was low. Further, the total amount of the oxazoline groups exceeds 0.5 mol compared to Examples 1 to 7 in which the total amount of the oxazoline groups of the water-soluble oxazoline group-containing polymer is in the range of 0.01 to 0.5 mol with respect to 1 mol of acid. In the case of Reference Example 8, the image density and the dot diameter were inferior.
Further, as can be seen from the comparison between Examples 10 to 14 and Reference Example 15 in Table 2 , in order to surely prevent the pretreatment liquid from solidifying, the amount of the oxazoline group of the water-soluble oxazoline group-containing polymer with respect to 1 mol of the acid. The total amount is preferably 0.5 mol or less.

1 is a schematic diagram (side explanatory view) of an example (first embodiment) of an image forming apparatus according to the present invention. Schematic including the case (exterior) of the ink cartridge of the present invention. The figure which shows the relationship between the mol number of an oxazoline group with respect to 1 mol of acids, and transcription | transfer density | concentration. The figure which shows the relationship between the mol number of an oxazoline group with respect to 1 mol of acids, and a dot diameter. The figure which shows the image forming apparatus of 2nd Embodiment which concerns on this invention. The figure which shows the image forming apparatus of 3rd Embodiment which concerns on this invention. The figure which shows the image forming apparatus of 4th Embodiment which concerns on this invention.

Explanation of symbols

P Printing unit Q Upper sheet feeding unit R Lower sheet feeding unit S Coating mechanism T Paper discharging mechanism U Acid solution dropping mechanism V Polymer solution dropping mechanism W Acid solution spraying mechanism X Polymer solution spraying mechanism 101 Image forming apparatus 103 Paper feed tray 104 Discharge Paper 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 111Y Maintenance unit G 112 Separation pad 113 Conveying belt 114 Recording medium 115 Tension roller 116 Charging roller 117 Paper 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

Claims (10)

Before discharging the aqueous recording ink containing the carboxyl group-containing resin , the acid and the water-soluble oxazoline group-containing polymer are added in an amount of 0.01 to 0 with respect to 1 mol of the total amount of oxazoline groups in the water-soluble oxazoline group-containing polymer. A pretreatment method characterized in that the surface of a recording medium is treated at a ratio of 5 mol . The recording medium surface is treated with a mixed solution of an acid and a water-soluble oxazoline group-containing polymer, and the acid and the water-soluble oxazoline group-containing polymer are mixed immediately before the recording medium surface is pretreated. The pretreatment method according to claim 1 . The pretreatment method according to claim 1, wherein the surface of the recording medium is treated by separately using an acid and a water-soluble oxazoline group-containing polymer. The pretreatment method according to any one of claims 1 to 3 , wherein the treatment is performed using a pretreatment liquid containing a surfactant in addition to the acid and the water-soluble oxazoline group-containing polymer. A pretreatment liquid for treating the surface of an aqueous recording ink containing an aqueous recording ink containing a carboxyl group-containing resin before recording on the recording medium, wherein the acid and the water-soluble oxazoline group-containing polymer contain a water-soluble oxazoline group. A pretreatment liquid comprising a total amount of oxazoline groups of a polymer at a ratio of 0.01 to 0.5 mol with respect to 1 mol of an acid . The pretreatment liquid according to claim 5 , further comprising a surfactant in addition to the acid and the water-soluble oxazoline group-containing polymer. A cartridge characterized by containing the pretreatment liquid according to claim 5 or 6 in a container. An aqueous recording ink discharge means containing a carboxyl group-containing resin, a storage means for storing an acid and a water-soluble oxazoline group-containing polymer, and an acid and a water-soluble oxazoline group-containing polymer before discharging the aqueous recording ink by the discharge means And a pretreatment means for treating the surface of the recording medium using a total amount of oxazoline groups of the water-soluble oxazoline group-containing polymer in a ratio of 0.01 to 0.5 mol with respect to 1 mol of the acid. An image forming apparatus. The storage means includes an acid storage means for storing an acid solution containing an acid, and a polymer storage means for storing a polymer solution containing a water-soluble oxazoline group-containing polymer. 9. The image forming apparatus according to claim 8 , further comprising a mixing unit serving as a processing liquid, wherein the preprocessing unit performs a preprocessing on the surface of the recording medium with the preprocessing liquid. The storage means includes an acid storage means for storing an acid solution containing an acid, and a polymer storage means for storing a polymer solution containing a water-soluble oxazoline group-containing polymer. 9. The image forming apparatus according to claim 8 , further comprising: an acid pretreatment unit that performs a pretreatment on the surface; and a polymer pretreatment unit that performs a pretreatment on the surface of the recording medium with a polymer solution. .

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