JP2008213388A - Image forming method and recorded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method which enables processing without problem from both environmental and safety aspects under an ordinary home environment and provides an image excellent in fixability and glossiness in a recorded image on a glossy medium with an ink composition containing a pigment as well as a high quality and clear image with little blotting, unevenness of shade or the like on ordinary paper, recycled paper or the like. <P>SOLUTION: The image forming method of the present invention is an image forming method for applying a coating liquid on the recorded image. The method is characterized in that the recorded image recorded with the ink composition comprising at least a resin component, the pigment and water is coated with the coating liquid comprising a plasticizer for dissolving or plasticizing the resin component, a humectant and water. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming method using an ink jet recording printer and a recorded matter.

  Inkjet printers have recently been commercialized as noiseless, high speed, high resolution non-impact printers. From the viewpoints of odor, safety, etc., water-based inks using water or water-soluble organic solvents are the mainstream as ink solvents used in ink jet recording. Further, water-soluble dyes have been conventionally used as colorants for inks used in ink jet recording, but dyes may be inferior in various properties such as light resistance and water resistance, and therefore, dye-based ink compositions. The recorded matter printed by is inferior in light resistance and water resistance. The water resistance is improved by an ink jet recording medium having an ink absorbing layer, but it is still not sufficient for plain paper and recycled paper.

  In contrast, pigments are superior in light resistance and water resistance compared to dyes, and in recent years, the use of pigments as colorants in ink compositions for ink jet recording has been studied for the purpose of improving light resistance and water resistance. In the case of a water-based ink using a pigment as a colorant, since the pigment is originally insoluble in water and easily separated (aggregation / precipitation, sedimentation, etc.) from the ink, in order to stably disperse this in water, Various studies have been conducted.

  One method of dispersing the pigment in water is to mix and disperse it together with a dispersant such as a dispersible resin. Many conventional dispersion methods (type of pigment used, particle size, type of dispersant used, and Dispersing means, etc.) and ink for ink jet recording have been proposed. Another method is to improve the dispersibility of the pigment by physically or chemically bonding a dispersibility-imparting group to the surface of the pigment particle so that it can be dispersed in water without a dispersant. Dispersed surface-treated pigments (hereinafter sometimes referred to as “surface-treated pigments”) have been proposed.

  In the ink using the pigment obtained by the above dispersion method, although the dispersion stability of the pigment in the ink can be ensured, the recorded image on the glossy media such as glossy paper obtained using the pigment is the above-mentioned In some cases, the fixing property and glossiness were inferior to those of other dye inks. The reason why the pigment ink and the dye ink behave differently is as follows. That is, in the dye ink, the dye is dissolved in a molecular form in the ink. When this is attached to the glossy media, the dye molecules penetrate into the ink receiving layer of the glossy media surface layer together with the ink liquid component, so that the glossiness of the glossy media surface layer is maintained. In addition, since the dye molecules penetrate into the medium, there is no problem in fixing the image. In contrast, in the pigment ink, since the pigment is dispersed in the form of particles in the ink, when the ink is attached, the ink liquid component penetrates into the ink receiving layer, but the pigment particles and the like are solid. The minute portion is difficult to penetrate and stays near the surface of the glossy media. For this reason, the recorded image obtained is inferior in fixability, and the image surface is inferior in smoothness, resulting in inferior glossiness. In particular, the above-mentioned surface-treated pigments have a more prominent defect because there are no fixing component and gloss component as they are.

  As a method for improving the above problems, various studies have been made on coating a recorded image obtained with an aqueous pigment ink. For example, it has been proposed to spray or apply a protective liquid composed of a low-boiling hydrocarbon solvent and a lipophilic resin dissolved therein (see Patent Document 1). In addition, it has been proposed to spray or apply a protective liquid made of cyclohexane, isohexane, monohydric alcohol, resin, or the like on a recorded image (see Patent Document 2). In addition, it has been proposed to coat a recorded image with an aqueous protective solution containing a resin having an acid value of greater than 110 (see Patent Document 3). Further, it has been proposed to coat a recorded image with a protective liquid containing a resin having a film forming ability by an ink jet recording method (see Patent Document 4).

JP 2002-240446 A JP 2004-175895 A JP 2004-195451 A JP 2005-81754 A

However, the prior art described above has the following problems.
Since the coating liquids according to Patent Document 1 and Patent Document 2 are mainly oil-soluble and volatile solvents, they are difficult to handle in terms of environment and safety and cannot be used in a general home environment. Further, in the coating liquids according to Patent Document 3 and Patent Document 4, it is necessary to contain a large amount of resin in order to effectively impart a fixing property and gloss to the recorded image. However, there is a problem that clogging or ejection failure due to drying of the protective liquid tends to occur on the nozzle surface of the printer head.

  Accordingly, the present invention has been made to solve the above-described problems. That is, the object of the present invention is that it can be handled without problems in terms of environment and safety even in a general home environment, and also has a fixing property and glossiness in a recorded image on a glossy medium by an ink composition containing a pigment. It is an object of the present invention to provide a coating liquid that is excellent in dischargeability and has excellent ejection stability and clogging properties in an ink jet recording method, and an image forming method using the same.

  As a result of intensive studies, the present inventor has described below a coating liquid suitable for application to a recorded image recorded on a glossy medium in advance using an ink composition containing a resin component, and an image forming method using the same. The knowledge that the said subject can be solved by setting it as the structure shown was acquired. The present invention is based on such knowledge. That is,

  (1) The image forming method of the present invention is an image forming method in which a coating liquid is applied to a recorded image. The resin component is recorded on a recorded image recorded with an ink composition comprising at least a resin component, a pigment, and water. The coating is performed with a coating liquid comprising a plasticizer, a humectant and water for dissolving or plasticizing the water.

  (2) In the image forming method of the present invention, the plasticizer contained in the coating solution is a phthalate ester, trimellitic acid ester, aliphatic dibasic acid ester, orthophosphoric acid ester, or ricinoleic acid ester. , Polyesters, epoxidized esters, acetic acid esters, and sulfonamides are one or two or more selected from the group consisting of sulfonamides.

  (3) The image forming method of the present invention is characterized in that the coating liquid and / or ink composition further contains a penetrating agent.

  (4) The image forming method of the present invention is such that the pigment contained in the ink composition directly or indirectly binds at least one of the functional group represented by the following formula or a salt thereof to the surface. It is treated and made dispersible in water without a dispersant.

  (5) The image forming method of the present invention is characterized in that the resin component contained in the ink composition is contained at least as a dispersion resin for dispersing the pigment.

  (6) In the image forming method of the present invention, the dispersion resin comprises a hydrophobic part and a hydrophilic part, and at least a part of the hydrophilic part contains an unneutralized group that is a part of the hydrophobic part. A neutralized group obtained by adding, wherein the abundance of the neutralized group is in a range of 20% or more and less than 60% in molar ratio to the sum of the unneutralized group and the neutralized group To do.

  (7) The image forming method of the present invention is characterized in that the resin component contained in the ink composition is contained at least as a resin emulsion.

  (8) The image forming method of the present invention is characterized in that the resin constituting the resin emulsion has a glass transition temperature (Tg) of 30 ° C. or higher.

  (9) The image forming method of the present invention is characterized in that the coating liquid is applied to at least a recorded image portion on a recording medium by an ink jet head to perform coating.

  (10) The image forming method of the present invention is characterized in that the recording image to be coated is formed by discharging the ink composition onto a recording medium using an ink jet head.

  (11) The recorded matter of the present invention is recorded using the image forming method described in any one of (1) to (10) above.

  With the image forming method having the above-described configuration, a clear image excellent in fixability and glossiness can be obtained even when recording on glossy media using an ink composition using a pigment. In such a configuration, unlike the prior art, it is not necessary to contain a large amount of resin component in the protective liquid (coating liquid). Therefore, reliability (ejection stability) when the coating liquid is applied to the ink jet recording system. Excellent clogging characteristics).

  Further, as will be described in detail later, when a dispersion resin for dispersing a pigment is included as an essential resin component in the ink composition of the present invention, the dispersion resin comprises a hydrophobic portion and a hydrophilic portion, and the hydrophilic portion Is a neutralizing group obtained by neutralizing an unneutralized group that is a part of the hydrophobic part, and the amount of neutralized group is less than the sum of the unneutralized group and the neutralized group When the molar ratio is 20% or more and less than 60%, or when the resin emulsion is included as the resin component, the glass transition temperature (hereinafter sometimes referred to as Tg) is 30 ° C. or higher. By including a resin emulsion made of resin, even on plain paper, recycled paper, etc., a phenomenon in which the flow of irregular ink in the recorded image and a larger spread than the attached ink droplets (hereinafter referred to as “bleeding”) Etc. Also it has the effect that a clear image is obtained in quality.

Hereinafter, the present invention will be described in detail based on preferred embodiments thereof.
The image forming method of the present invention is an image forming method in which a coating liquid is applied to a recorded image, wherein the resin component is dissolved or dissolved on a recorded image recorded with an ink composition comprising at least a resin component, a pigment, and water. The coating is performed with a coating liquid comprising a plasticizer to be plasticized, a humectant, and water. Also, the plasticizer contained in the coating liquid is phthalic acid esters, trimellitic acid esters, aliphatic dibasic acid esters, orthophosphoric acid esters, ricinoleic acid esters, polyesters, epoxidized esters, acetic acid. It is one or more selected from the group consisting of esters and sulfonamides. The coating liquid containing such a plasticizer is excellent in the effect of improving the fixability / glossiness of an image recorded on a glossy medium by the ink composition according to the present invention.

  The reason for this is not clear yet, but is estimated as follows. In the image forming method of the present invention, an image is first recorded on a glossy medium with an ink composition containing a resin component. When the pigment is used as the colorant of the ink composition to be used, as described above, the solid content in the ink mainly composed of pigment particles and the resin component is present on the glossy media surface, and the image surface Is difficult to smooth. Therefore, the glossiness of the image may be poor. Conventionally, in order to improve the glossiness, various studies have been made on ink additives and ink components (mainly, the structure of the resin component to be added, solvent types, and combinations thereof) to impart glossiness. However, satisfactory results were not obtained.

  However, when the coating liquid according to the present invention is applied to the image portion, the resin component present in the image portion is plasticized and dissolved by the action of the contained plasticizer. The plasticized / dissolved material of the resin component enters between the pigment particles and the surface of the pigment particles, and then forms a uniform resin film with drying. This resin film is rich in smoothness and uniformly reflects light incident on the image surface, which is considered to improve the glossiness of the image. Further, since this resin film also exhibits an action of firmly bonding between the pigment particles and between the pigment particles and the glossy media, it is considered that the resin film also has an effect of improving the fixability of the image.

The coating liquid and ink composition in the image forming method of the present invention will be described below.
<Coating solution>
In the image forming method of the present invention, in the image forming method for applying a coating liquid to a recorded image, a coating liquid containing at least water, a plasticizer, and a humectant as essential components is used. Below, the component of the coating liquid used for this invention is demonstrated.

[Plasticizer]
It is essential that the coating liquid according to the present invention contains a plasticizer. This plasticizer has the feature of functioning as a good plasticizing / dissolving agent for the resin component essential to the ink composition of the present invention, which will be described in detail later. When such a plasticizer is included, as described above, the resin component present in the image portion is plasticized and dissolved, and then a uniform resin film is formed with drying. Since this resin film is rich in smoothness and uniformly reflects light incident on the image surface, it is excellent in the effect of improving the glossiness of the image. Further, this resin film also has an effect of improving the fixability of an image because it exhibits an action of firmly bonding between the pigment particles and between the pigment particles and the glossy media.

Specifically, as a plasticizer having such an effect, as phthalates, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, bis (2-ethylhexyl) phthalate, di-n-octyl phthalate, diisodecyl phthalate, butyl benzyl phthalate, Examples include diisononyl phthalate, ethyl phthalyl ethyl glycolate, and diundecyl phthalate.
Trimellitic acid esters include tris (2-ethylhexyl) trimellitate.
Examples of aliphatic dibasic acid esters include dimethyl adipate, dibutyl adipate, diisobutyl adipate, bis (2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, bis (butyl diglycol) adipate, bis (2-ethylhexyl) azelate, Examples include dimethyl sebacate, dibutyl sebacate, bis (2-ethylhexyl) sebacate, and diethyl succinate.
The orthophosphates include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tris (2-ethylhexyl) phosphate, tris (butoxyethyl) phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl. Examples include phosphate and 2-ethylhexyl diphenyl phosphate.
Examples of ricinoleic acid esters include methyl acetyl ricinoleate.
Polyesters include poly (1,3-butanediol adipate).
Epoxidized esters include epoxidized soybean oil.
Examples of acetates include glyceryl triacetate and 2-ethylhexyl acetate.
Examples of sulfonamides include N-butylbenzenesulfonamide.

  These plasticizers mentioned above can be used in the coating liquid according to the present invention by mixing one kind or two or more kinds.

  The content of the plasticizer contained in the coating liquid according to the present invention is preferably in the range of 0.1% by weight to 10% by weight. When the content is 0.1% by weight or more, the above-described effects are sufficiently exhibited. On the other hand, if it is 10% by weight or less, the viscosity of the coating liquid can be adjusted to a suitable range in the ink jet recording method, and the ejection stability is also good. In addition, the reactivity to the ink flow path member (especially a plastic member) in the printer can be kept low, and there is no problem that the member is eroded even during long-term filling.

[Humectant]
It is essential that the coating liquid according to the present invention contains a humectant. The moisturizing agent used in the present invention is selected from those having low volatility, high water retaining ability, and high compatibility with the plasticizer described above. By doing so, it is possible to suppress drying of the coating liquid due to water evaporation and to prevent alteration of the composition of the coating liquid due to prolonged standing. For this reason, for example, even when the apparatus is in a rest state for a long time after being filled, the effect of the coating liquid according to the present invention is maintained, and the reactivity of the ink flow path member in the printer due to the plasticizer can be suppressed. .

  In detail, the humectant having the above-mentioned characteristics includes glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 1,4- Polyols such as butanediol, 1,5-pentanediol and pentaerythritol, and lactams such as 2-pyrrolidone and N-methyl-2-pyrrolidone can be used.

  Furthermore, a water-soluble solid humectant can be used in combination and added for the purpose of assisting the ability of the above materials. Specifically, diols such as 1,6-hexanediol, 1,8-octanediol, 2,2-dimethyl-1,3-propanediol, and 2,2-diethyl-1,3-propanediol, trimethylolethane , Trimethylolpropane, etc., ureas, glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, glucitol (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, etc. Examples of saccharides, oligosaccharides and polysaccharides and derivatives of these saccharides include reducing sugars, oxidized sugars, amino acids, thiosaccharides, and the like of the aforementioned sugars. Sugar alcohol is particularly preferable, and specific examples include maltitol and sorbit.

  The addition amount of these humectants is preferably in the range of 1% by weight to 50% by weight based on the total amount of the coating liquid, alone or in combination. If it is 1% by weight or more, the above-described effects are sufficiently exhibited. If it is 50% by weight or less, the viscosity of the coating liquid can be adjusted to a suitable range in the ink jet recording system, and the ejection stability is also good.

  The humectant described above can also be added to the ink composition described below. In that case, as in the case where it is included in the coating liquid according to the present invention, it is possible to suppress the drying of the ink composition due to water evaporation and to prevent the composition of the ink composition from deteriorating due to long-term standing. ,preferable.

[water]
Water is a coating medium according to the present invention and a medium serving as the center of the ink composition described below. Preferred water is ion-exchanged water, ultrafiltered water, reverse water for the purpose of reducing ionic impurities as much as possible. Pure water such as osmotic water or distilled water, or ultrapure water can be used. Further, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, it is preferable because generation of mold and bacteria can be prevented when the coating liquid and the ink composition are stored for a long period of time.

<Ink composition>
The image forming method of the present invention is an image forming method in which a coating liquid is applied to a recorded image. On the recorded image recorded with an ink composition comprising at least a resin component and a pigment, the above-described coating liquid is used for coating. It is characterized by giving. The constituent elements of the ink composition used in the present invention will be described below.

[Pigment]
Examples of the pigment essential for the ink composition in the invention include organic pigments insoluble or hardly soluble in an aqueous medium, carbon black, and the like.
In the present invention, specific examples of preferable carbon black include No. 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, No2200B, etc. (all trade names, manufactured by Mitsubishi Chemical Corporation), color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U , Special Black 6, 5, 4A, 4, 250, etc. (all trade names, manufactured by Degussa), Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700, etc. (all trade names, Colombia) (Manufactured by Carbon Co., Ltd.), Regar 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12, etc. (all trade names, manufactured by Cabot Corporation). In addition, these are description of an example of the carbon black suitable for this invention, and this invention is not limited by these. These carbon blacks may be used singly or as a mixture of two or more.
These pigments are added in an amount of 0.5 to 15% by weight, preferably 1 to 10% by weight, based on the total amount of the ink composition.

Preferred organic pigments in the present invention include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments. And diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments and azo pigments.
Specific examples of the organic pigment used in the ink composition according to the present invention include the following.
Examples of the pigment used in the cyan ink composition include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60, etc .; C.I. I. Bat blue 4, 60 and the like, preferably C.I. I. Pigment Blue 15: 3, 15: 4, and one or a mixture of two or more selected from the group consisting of 60. These pigments are contained in an amount of about 0.5 to 15% by weight, preferably about 1 to 10% by weight, based on the cyan ink composition.
Examples of the pigment used in the magenta ink composition include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, C.I. I. Pigment violet 19 and the like, preferably C.I. I. Pigment red 122, 202, and 209, C.I. I. One or a mixture of two or more selected from the group consisting of pigment violet 19. These pigments are contained in an amount of about 0.5 to 15% by weight, preferably about 1 to 10% by weight, based on the magenta ink composition.
Examples of the pigment used in the yellow ink composition include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 119, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, 185, etc., preferably C.I. I. One or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128, and 138. These pigments are contained in an amount of about 0.5 to 15% by weight, preferably about 1 to 10% by weight, based on the yellow ink composition.
Examples of the pigment used in the orange ink composition include C.I. I. Pigment Orange 36 or 43, or a mixture thereof. These pigments are contained in an amount of about 0.5 to 15% by weight, preferably about 1 to 10% by weight, based on the orange ink composition.
Examples of the pigment used in the green ink composition include C.I. I. Pigment Green 7 or 36 or a mixture thereof. These pigments are contained in an amount of about 0.5 to 15% by weight, preferably about 1 to 10% by weight, based on the green ink composition.

  In the ink composition of the present invention, the pigments described above are preferably used. As a form for including the pigment in the ink, a dispersion which can be dispersed in water by a dispersion resin (resin having an anionic group) described later as a resin component, or the surface thereof is represented by the following formula: A surface-treated pigment that is surface-treated so that at least one of functional groups or salts thereof is bonded directly or indirectly and is dispersible in water without a dispersant is preferred.

Hereinafter, the dispersion and the surface-treated pigment will be described in detail.
(Dispersion)
The ink composition according to the present invention includes, as an example, a dispersion in which the above-described pigment is dispersible in water by a dispersion resin that is a resin component. The dispersion resin used in the ink composition of the present invention is insoluble in water alone, and is soluble in an organic solvent (preferably a hydrophilic organic solvent such as acetone or methyl ethyl ketone) used in the method for producing a dispersion described later in the examples. It is essential to dissolve and plasticize with the plasticizer described above and to have both a hydrophobic part and a hydrophilic part as its resin structure.
Here, the hydrophobic portion refers to a repeating unit having an alkyl group, a cycloalkyl group, an aromatic ring, or an unneutralized group. An unneutralized group is a group that can be neutralized by a neutralizing agent, and examples thereof include an acid group and an alkaline group. Specific examples of the unneutralized group include a carboxylic acid group and a sulfonic acid group. Moreover, as a hydrophilic part, the repeating unit which has a hydroxyl group, an amino group, an amide group, and a neutralizing group is shown. The neutralizing group is a group formed by neutralizing an unneutralized group, and is preferably an ionic group. The unneutralized group and the neutralized group are preferably anionic groups, and particularly suitable when the unneutralized group is a carboxylic acid group and the neutralized group is a carboxylic acid anion group (carboxylate group). Can be illustrated. Examples of the carboxylate include lithium carboxylate, sodium carboxylate, potassium carboxylate, and ammonium carboxylate. When the dispersion resin has the above-described structure, the hydrophobic resin can be firmly adsorbed on the hydrophobic surface of the pigment to include the pigment. Furthermore, since the hydrophilic part is compatible with water, it can be a dispersion that is stably dispersed in water.

The dispersion resin having an anionic group is obtained by polymerizing, for example, a monomer having an anionic group (hereinafter referred to as an anionic group-containing monomer) and, if necessary, another monomer that can be copolymerized with these monomers in a solvent. Is obtained. Examples of the anionic group-containing monomer include a monomer having a carboxylic acid group and a monomer having a sulfonic acid group.
As the monomer having a carboxylic acid group, an acrylic monomer containing one or two carboxylic acid groups in the repeating unit is preferable. Specific examples of the monomer having a carboxylic acid group include acrylic acid, methacrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, fumaric acid, maleic acid and the like. Among these, acrylic acid, methacrylic acid, and maleic acid are preferable. Specific examples of the monomer having a sulfonic acid group include styrene sulfonic acid, isoprene sulfonic acid, sulfobutyl methacrylate, and allyl sulfonic acid. Furthermore, after polymerizing the resin, it is also preferable to sulfonate with a sulfonating agent such as sulfuric acid, fuming sulfuric acid, sulfamic acid and the like.

  Specific examples of other monomers that can be copolymerized with the anionic group-containing monomer include methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid-n-propyl, acrylic acid-n-butyl, and acrylic acid-t-. Butyl, 2-ethylhexyl acrylate, n-octyl acrylate, lauryl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, methacrylic acid n-propyl, methacrylic acid n-butyl, (Meth) acrylic esters such as isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, stearyl methacrylate, tridecyl methacrylate, benzyl methacrylate, etc. ; Steer Addition reaction product of oil fatty acid and (meth) acrylic acid ester monomer having oxirane structure such as addition reaction product of acid and glycidyl methacrylate; oxirane compound containing alkyl group having 3 or more carbon atoms and (meth) acrylic Addition reaction product with acid; styrene monomer such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-tert-butylstyrene, etc .; such as benzyl itaconate Itaconic acid esters; maleic acid esters such as dimethyl maleate; fumaric acid esters such as dimethyl fumarate; acrylonitrile, methacrylonitrile, vinyl acetate, isobornyl acrylate, isobornyl methacrylate, aminoethyl acrylate, acrylic acid Aminopropyl, aqua Methylaminoethyl acrylate, methylaminopropyl acrylate, ethylaminoethyl acrylate, ethylaminopropyl acrylate, aminoethylamide acrylate, aminopropylamide acrylate, methylaminoethylamide acrylate, methylaminopropylamide acrylate, Acrylic acid ethylaminoethylamide, acrylic acid ethylaminopropylamide, methacrylic acid amide, aminoethyl methacrylate, aminopropyl methacrylate, methylaminoethyl methacrylate, methylaminopropyl methacrylate, ethylaminoethyl methacrylate, ethylamino methacrylate Propyl, methacrylic acid aminoethylamide, methacrylic acid aminopropylamide, methacrylic acid methylaminoethylamide, methacrylic acid methylaminoamide Pyramide, ethyl aminoethylamide methacrylate, ethyl aminopropyl amide methacrylate, hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, Examples include 2-hydroxypropyl methacrylate, N-methylolacrylamide, and allyl alcohol.

  These dispersion resins preferably have a weight average molecular weight in the range of 1,000 to 200,000, particularly preferably in the range of 3,000 to 150,000. When the weight average molecular weight of the dispersion resin is within this range, the function as a pigment coating film or a coating film in the ink composition can be sufficiently exhibited.

  Examples of the alkaline compound that neutralizes a part of the unneutralized group of the dispersion resin having an anionic group include organic amines and alkali metal salt compounds. Specific examples of organic amines include salts with volatile amine compounds such as ammonia, triethylamine, tributylamine, dimethylethanolamine, diisopropanolamine and morpholine, diethanolamine, triethanolamine, tripropanolamine and other highly volatile compounds. Examples include salts of boiling organic amines. Specific examples of the alkali metal salt compound include compounds having lithium, sodium and potassium as the alkali metal, preferably an alkali metal hydroxide salt such as sodium hydroxide, potassium hydroxide and lithium hydroxide, more preferably potassium hydroxide. Can be mentioned.

  In the dispersion used in the ink composition of the present invention, the balance between the hydrophobic portion and the hydrophilic portion of the dispersion resin described above is important, and the amount of neutralizing groups that are part of the hydrophilic portion is the dispersion. Greatly affects the dispersion stability of the toner, the ejection stability from the printer head, and the image quality of the recorded matter. The ratio is preferably 20% or more and less than 60% in a molar ratio with respect to the sum of the unneutralized group which is a part of the hydrophobic part in the dispersion resin and the neutralized group which is a part of the hydrophilic part . Within this range, it is possible to obtain an ink composition having higher storage stability and ejection stability, and particularly excellent image quality on plain paper, recycled paper, and the like. If the amount of the neutralizing group is 20% or more, the balance between the hydrophobic portion and the hydrophilic portion becomes good, and the dispersion of the pigment by the dispersing resin is stabilized, so that the aggregation and sedimentation of the pigment can be prevented. Also, if it is less than 60%, the penetration of the ink solid content (particularly pigment particles) into the paper is suppressed particularly when an image is formed on plain paper such as plain paper or recycled paper. There is an effect that pigment particles can be present on the paper surface, and as a result, the color developability is improved, and a clear recorded image with less bleeding and high density can be obtained.

  The amount of the anionic group in the dispersion resin is such that the acid value is about 30 KOHmg / g or more, preferably about 50 KOHmg / g to about 250 KOHmg / g. When the acid value of the dispersion resin is within such a range, the storage stability of the pigment particles formed into a coating film is improved, and the water resistance of the recorded image is improved.

  By using the dispersion resin described above in combination with the ink composition using the dispersion and the above-described coating liquid, an image having excellent glossiness and fixability can be formed on an image on glossy media. it can.

(Surface treatment pigment)
Next, the surface-treated pigment will be described in detail.
In the ink composition of the present invention, as another example of the pigment, the surface is treated and dispersed so that at least one of the functional group represented by the following formula or a salt thereof is bonded directly or indirectly to the surface of the pigment described above. It comprises a surface-treated pigment that is dispersible in water without an agent.

  In the surface-treated pigment, the functional group or salt thereof bonded to one pigment particle may be a single type or a plurality of types. The type and degree of the functional group bonded or the salt thereof may be appropriately determined in consideration of the dispersion stability in the ink composition, the color density, the drying property on the front surface of the inkjet head, and the like. Further, in the surface-treated pigment contained in the ink composition of the present invention, the functional group or a salt thereof may be present at least on the particle surface, and may be contained inside the particle.

  Various known surface treatment means can be applied as the surface treatment means for bonding the functional group or a salt thereof directly or indirectly to the surface of the pigment particles. For example, means for treating a commercially available oxidized carbon black with ozone or a sodium hypochlorite solution to further oxidize the carbon black to make the surface more hydrophilic (for example, JP-A-7-258578, JP-A-H10-238707). 8-3498, JP-A-10-120958, JP-A-10-195331, JP-A-10-237349), means for treating carbon black with 3-amino-N-alkyl-substituted pyridium bromide ( For example, JP-A-10-195360 and JP-A-10-330665), an organic pigment is dispersed in a solvent in which the organic pigment is insoluble or hardly soluble, and a sulfone group is introduced onto the pigment particle surface by a sulfonating agent. Means (for example, JP-A-8-283596, JP-A-10-110110, JP-A-10-110 No. 11), means for dispersing a organic pigment in a basic solvent that forms a complex with sulfur trioxide, treating the surface of the organic pigment by adding sulfur trioxide, and introducing a sulfone group or a sulfonamino group (For example, JP-A-10-110114), a method of introducing a water-solubilizing functional group and a polymer onto a pigment surface through a phenylene group bonded to carbon black by an azo coupling reaction (for example, JP-A-2000-2000). No. -53902) and the like, but the preparation means for the surface-treated pigment used in the ink composition of the present invention is not limited to these means.

  The surface-treated pigment used in the ink composition of the present invention can introduce (chemically bond) a polymer substance directly or indirectly to the surface of the pigment particles. Introduction of the polymer substance to the pigment surface is realized by an acylation reaction or an ester group nucleophilic substitution reaction. Specific examples of such a high-molecular substance include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and their homologs (polyethylene glycol having 1 to 10 carbon atoms in the alkyl group, polypropylene glycol, and polytetramethylene glycol). Monoalkyl ethers or monoaryl ethers, amines of methoxypolyethylene glycol, polyvinyl alcohol, copolymers of polyvinyl alcohol and polyvinyl acetate, and the like. These polymer materials desirably have at least one amino group or hydroxyl group at the terminal.

  When the surface-treated pigment described above is used in the ink composition according to the present invention and an image is formed on plain paper such as plain paper or recycled paper, the penetration of the pigment particles into the paper is suppressed. There is an effect that pigment particles can be present on the paper surface, and as a result, the color developability is improved and a high quality and clear recorded image can be obtained. The reason is not clear, but it is presumed as follows. The surface-treated pigment in the present invention is stable because at least one of the functional groups represented by the above formula or a salt thereof is bonded in the ink, and the electrostatic repulsive force acts between the particles by ion dissociation. However, when the ink adheres to the recording medium, an ionic substance in the recording medium, for example, alkaline earth metal ions such as magnesium and calcium, dissolves in the ink, thereby the functional group and the ion. As a result, the pigment particles are aggregated by the salting-out reaction and the pigment particles are aggregated, whereby separation from the liquid component in the ink occurs. As a result, the pigment aggregate first settles and adsorbs on the surface of the recording medium, and then the liquid component penetrates and diffuses into the surface and inside of the recording medium. Therefore, it seems that an image with less bleeding can be obtained.

  The particle diameter of the dispersion / surface-treated pigment used in the ink composition of the present invention is preferably 500 nm or less, more preferably 300 nm or less, and even more preferably an average particle diameter from the viewpoint of dispersion stability. In the range of 10 nm to 150 nm.

[Resin component]
In the ink composition of the present invention, a resin component is essential. This resin component is preferably included in the ink composition in the form of the above-described dispersion (in which the pigment can be dispersed in water with a dispersion resin) and / or in the form of a resin emulsion. Below, the resin emulsion as a resin component is demonstrated in detail.

(Resin emulsion)
The ink composition in the present invention can contain a resin emulsion as a resin component. The resin emulsion suppresses the above-described pigment from permeating into the recording medium, particularly plain paper, recycled paper, and the like, thereby improving the color developability. Further, when the above-described coating liquid is coated, the resin emulsions and the resin emulsion and the pigment particles are bonded together, so that the pigment is fixed on the recording medium and the fixability can be improved. Furthermore, because the coating emulsion forms a uniform and smooth film in such a manner that the resin emulsion covers the pigment by the above-mentioned action of the coating liquid, an effect of forming an image having excellent glossiness especially on an image on a glossy medium. Also have.

  Examples of the resin constituting the resin emulsion having such characteristics include acrylic resins, methacrylic resins, styrene resins, urethane resins, acrylamide resins, epoxy resins, and the like, and mixed systems of these resins. May be used. Among these resins, more preferred are styrene-acrylic acid copolymers, styrene-acrylic acid-alkyl acrylate copolymers, styrene-maleic acid copolymers, styrene-maleic acid-alkyl acrylates. Examples include ester copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-alkyl acrylate copolymers, styrene-maleic acid-half ester copolymers, and the like.

  These resins are required to have both a hydrophobic part and a hydrophilic part as a structure. Here, the hydrophobic portion refers to a repeating unit having an alkyl group, a cycloalkyl group, an aromatic ring, or an unneutralized group. An unneutralized group is a group that can be neutralized by a neutralizing agent, and examples thereof include an acid group and an alkaline group. Specific examples of the unneutralized group include a carboxylic acid group and a sulfonic acid group. Moreover, as a hydrophilic part, the repeating unit which has a hydroxyl group, an amino group, an amide group, and a neutralizing group is shown. The neutralizing group is a group formed by neutralizing an unneutralized group, and is preferably an ionic group. The unneutralized group and the neutralized group are preferably anionic groups, and particularly suitable when the unneutralized group is a carboxylic acid group and the neutralized group is a carboxylic acid anion group (carboxylate group). Can be illustrated. Examples of the carboxylate include lithium carboxylate, sodium carboxylate, potassium carboxylate, and ammonium carboxylate. Since the resin constituting the resin emulsion has the above-described structure, the hydrophobic part exists inside the resin emulsion and is isolated from the water, and since the hydrophilic part exists on the surface of the resin emulsion, it can be adjusted to water. It can be a resin emulsion that is stably dispersed in water. Moreover, after adhering on the recording medium, the above-described coating liquid is coated, so that the resin emulsions or the resin emulsion and the pigment can be bonded and formed into a film, and the hydrophobic portion can cover the surface of the film. This film is insoluble in water and does not re-disperse, and is firmly fixed on the recording medium together with the pigment, so that the image fixability and water resistance are improved.

  Such resin emulsions may be synthesized and used so as to satisfy various characteristics, but commercially available products may also be used. Specifically as a commercial item, mobile 701 (Tg: -19 degreeC), mobile 743 (Tg: 39 degreeC), mobile 745 (Tg: 21 degreeC), mobile 940 (Tg: 1 degreeC), mobile 1930 (Tg: 1 ° C), mobile 664 (Tg: 6 ° C), mobile DM5 (Tg: -3 ° C), mobile 700 (Tg: -2 ° C), mobile 792 (Tg: -2 ° C), mobile DM772 (Tg: 3 ° C) ), Mobile 865 (Tg: 1 ° C), Mobile 870 (Tg: 19 ° C), Mobile 928 (Tg: 5 ° C), Mobile 1750T (Tg: 16 ° C), Mobile 1751 (Tg: 16 ° C), Mobile 1760 ( Tg: 7 ° C), mobile LDM6316 (Tg: 17 ° C), mobile 7200 (Tg: 24 ° C), mobile 727 ( g: 5 ° C), mobile 752 (Tg: 16 ° C), mobile 837 (Tg: 10 ° C), mobile 860 (Tg: 3 ° C), mobile 864 (Tg: 4 ° C), mobile 864M (Tg: 4 ° C) , Mobile DM60 (Tg: 0 ° C.), Mobile DM 765 (Tg: −19 ° C.), Mobile 937 (Tg: −42 ° C.), Mobile 1906 (Tg: −45 ° C.), Mobile LDM 6300 (Tg: 10 ° C.), Mobile 742N (Tg: 37 ° C.), mobile 749E (Tg: 25 ° C.), mobile 752 (Tg: 16 ° C.), mobile 916 (Tg: −5 ° C.), mobile 1700A (Tg: 37 ° C.), mobile 7210 (Tg: 16 ° C), mobile 747 (Tg: 42 ° C), mobile 6520 (Tg: 40 ° C), mobile 7 02 (Tg: −35 ° C.), mobile LDM7010 (Tg: 34 ° C.), mobile VDM7410 (Tg: −4 ° C.), mobile DM 772 (Tg: 3 ° C.), mobile DM 774 (Tg: 10 ° C.), mobile 947 (Tg) : -55 ° C), mobile LDM6481 (Tg: -22 ° C), mobile LDM6880 (Tg: 9 ° C), mobile DM758 (Tg: -60 ° C), mobile DM765 (Tg: -19 ° C), mobile 650 (Tg: −37 ° C.), mobile 760H (Tg: −17 ° C.), mobile 761HG (Tg: −35 ° C.), mobile 763 (Tg: −18 ° C.), mobile 412 (Tg: −62 ° C.), mobile 490 (Tg: −53 ° C.), mobile S-71 (Tg: −53 ° C.), mobile 987 (Tg: -2 ° C), Mobile 1410 (Tg: -8 ° C), Mobile 630 (Tg: 27 ° C), Mobile 620 (Tg: -22 ° C), Mobile 730L (Tg: -13 ° C), Mobile 735 (Tg: 14) ° C), mobile 767 (Tg: 25 ° C), mobile 790 (Tg: 102 ° C), mobile 9000 (Tg: 46 ° C), mobile 880 (Tg: 3 ° C), mobile DM60 (Tg: 3 ° C), mobile 8020 (Tg: −22 ° C.), Mobile 8030 (Tg: 17 ° C.), Mobile 8055 (Tg: 78 ° C.), Mobile 8201 (Tg: 8 ° C.), Mobile 787 (Tg: 14 ° C.), Mobile 710 (Tg: 9) ° C), mobile 718 (Tg: -6 ° C), mobile 776 (Tg: -20 ° C), mobile 952 (Tg:- 8 ° C), Mobile 963A (Tg: -19 ° C), Mobile DM 772 (Tg: 6 ° C), Mobile 975A (Tg: 27 ° C), Mobile 3200 (Tg: -21 ° C), Apletan 760H (Tg: -17 ° C) ), Apletan 2200 (Tg: 19 ° C.), Apretan 2000 (Tg: 19 ° C.), Apretan 3510 (Tg: 0 ° C.), Apretan 3410 (Tg: −32 ° C.) (all trade names, manufactured by Clariant Japan Co., Ltd.) PCL series 0619 (Tg: −4 ° C.), PCL series 0623A (Tg: −6 ° C.), PCL series 0640 (Tg: 55 ° C.), PCL series 0693 (Tg: 20 ° C.), PCL series 0695 (Tg: − 4 ° C), PCL series 0696 (Tg: -12 ° C), PCL series 0850 (Tg: 7) ), PCL series 0890 (Tg: −17 ° C.), SB series 0561 (Tg: −63 ° C.), SB series 0589 (Tg: 0 ° C.), SB series 0602 (Tg: 40 ° C.), SB series 2108 (Tg: -66 ° C), SB series 0533 (Tg: -20 ° C), SB series 0545 (Tg: -31 ° C), SB series 0548 (Tg: -49 ° C), SB series 0568 (Tg: -23 ° C), SB Series 0569 (Tg: -4 ° C), SB series 0573 (Tg: -9 ° C), SB series 0597C (Tg: 28 ° C), AE series AE116 (Tg: 50 ° C), AE series AE119 (Tg: 55 ° C) AE series AE120 (Tg: -10 ° C), AE series AE121 (Tg: 58 ° C), AE series AE125 (Tg : AE series AE134 (Tg: 48 ° C), AE series AE137 (Tg: 48 ° C), AE series AE140 (Tg: 53 ° C), AE series AE173 (Tg: 60 ° C), AE series AE200 (Tg) : -45 ° C), AE series AE311 (Tg: -50 ° C), AE series AE318 (Tg: 5 ° C), AE series AE337 (Tg: -30 ° C), AE series 343 (Tg: 0 ° C), AE series 362 (Tg: -5 ° C), AE series AE373B (Tg: 10 ° C), AE series AE379A (Tg: 20 ° C), AE series AE513A (Tg: -48 ° C), AE series AE517 (Tg: -48 ° C) AE series AE604 (Tg: 5 ° C), AE series AE610C (Tg: -62 ° C), AE series AE815 (Tg: 5 ° C), AE series AE945 (Tg: -17 ° C), AE series AE950 (Tg: -20 ° C), AE series AE986A (Tg: 2 ° C) (all trade names, manufactured by JSR Corporation) ), Jonkrill 7100 (Tg: −10 ° C.), Jonkrill 390 (Tg: −5 ° C.), Jonkrill 1674 (Tg: −4 ° C.), Jonkrill 711 (Tg: 0 ° C.), Jonkrill 1695 (Tg) : 5 ° C), Joncryl 511 (Tg: 9 ° C), Joncryl 7001 (Tg: 12 ° C), Joncryl 632 (Tg: 12 ° C), Joncryl 741 (Tg: 15 ° C), Joncryl 450 (Tg) : 16 ° C), Joncryl 840 (Tg: 16 ° C), Joncryl 74J (Tg: 22 ° C), PDX-7111B (Tg: 19 ° C), HR -1645 (Tg: 21 ° C.), Jonkrill 734 (Tg: 30 ° C.), Jonkrill 852 (Tg: 31 ° C.), Jonkrill 7600 (Tg: 35 ° C.), Jonkrill 775 (Tg: 37 ° C.), John Krill 537 (Tg: 49 ° C), Jonkrill 1535 (Tg: 50 ° C), PDX-7630A (Tg: 53 ° C), Jonkrill 352 (Tg: 56 ° C), Jonkrill 352D (Tg: 56 ° C), PDX -7145 (Tg: 56 ° C.), Jonkrill 538 (Tg: 66 ° C.) (all trade names, manufactured by BASF Japan Ltd.) and the like.

  One or a plurality of these resin emulsions can be used in the ink composition of the present invention, and at least one of them can have a Tg (glass transition temperature) of the resin constituting it of 30 ° C. or higher. preferable. The reason is that by including a resin emulsion having a Tg of the resin of 30 ° C. or higher, more pigment can be present on the surface of the recording medium, and as a result, the color developability becomes higher, that is, the ink is particularly plain paper. This is because it has the effect of suppressing the phenomenon that it penetrates to the back side of the printed surface such as recycled paper.

  The addition amount of these resin emulsions may be appropriately determined in consideration of fixing properties, color development properties, etc., but is preferably 20% by weight or less in terms of solid content in the ink composition.

  In addition, the ink composition according to the present invention preferably contains a humectant essential for the coating liquid described above. In that case, as in the case where it is included in the coating liquid according to the present invention, it is possible to suppress the drying of the ink composition due to water evaporation and to prevent the composition of the ink composition from deteriorating due to long-term standing. ,preferable.

<Other additives to coating liquid and ink composition>
The coating liquid according to the present invention contains the above-described plasticizer, humectant, and water as essential components, and the ink composition includes the above-described pigment (pigment contained in the dispersion or surface-treated pigment), resin component ( Dispersion resin, resin emulsion) and water contained in the dispersion are essential components. By forming an image using the coating liquid and ink composition having such a configuration, even if recording is performed on glossy media using an ink composition containing a pigment, a clear and excellent fixability and glossiness are obtained. An image can be obtained and is excellent in reliability (ejection stability, clogging characteristics) when the coating liquid is applied to an ink jet recording system. -Various characteristics of each ink composition can be further improved. Hereinafter, the components will be described.

[Penetration agent]
The coating liquid and ink composition according to the present invention preferably further contain a penetrant. By including a penetrant, in the coating liquid, the permeability to the resin component on the image recorded by the ink composition is improved, and the resin component can be plasticized and dissolved effectively and efficiently. The plasticized / dissolved material can more uniformly cover between the pigment particles and the surface thereof. For this reason, it is possible to provide the characteristics of further improving the fixability and glossiness of the image on the glossy medium. In addition, the ink composition has the effect of increasing the permeability to the recording medium and improving the drying speed of the recorded image. Furthermore, the irregular flow of ink in the recorded image and the phenomenon of spreading larger than the adhering ink droplets (hereinafter referred to as “bleeding”), irregular image density unevenness (hereinafter referred to as “light / dark unevenness”). As a result, a high quality and clear recorded image can be obtained.

As an example of a penetrant having such an effect, it is preferable to select a glycol monoether derivative of a polyhydric alcohol or 1,2-alkyldiols.
As the glycol monoether derivative of a polyhydric alcohol, a derivative of a polyhydric alcohol in which the alkyl group has 3 or more carbon atoms is particularly preferable. Specifically, ethylene glycol monobutyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-tert-butyl ether Diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, diethylene glycol mono-tert-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol mono-tert-butyl ether, propylene glycol mono-n-propyl ether, Propylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether Ether, dipropylene glycol mono -n- butyl ether, dipropylene glycol mono -n- propyl ether, dipropylene glycol monomethyl -iso- propyl ether. The addition amount of the glycol monoether derivative of the polyhydric alcohol is preferably within a range of 15% by weight or less based on the total amount of the coating liquid or the total amount of the ink composition.
As the 1,2-alkyldiols, 1,2-alkyldiols having 4 to 8 carbon atoms such as butanediol, pentanediol, hexanediol, heptanediol, and octanediol are preferable. Among these, 1,2-hexanediol, 1,2-heptanediol, and 1,2-octanediol having 6 to 8 carbon atoms are particularly preferable because of the strong effect of improving permeability described above. These 1,2-alkyldiols are preferably added in an amount of 5% by weight or less based on the total amount of the coating liquid or the total amount of the ink composition.

  Other examples of penetrants include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, 2,2-dimethyl-1-propanol, n-butanol, 2-butanol, tert-butanol, and iso-butanol. Water-soluble ones such as 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, n-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, etc. And monohydric alcohols. The addition amount of these monohydric alcohols is preferably in the range of 10% by weight or less based on the total amount of the water-based ink composition.

  Furthermore, another example of the penetrating agent is an acetylene glycol surfactant or an acetylene alcohol surfactant. Acetylene glycol surfactants and acetylene alcohol surfactants have less foaming properties and superior antifoaming properties compared to other surfactants. Therefore, it is possible to efficiently record a coating or an image without causing defects such as missing dots due to the coating liquid or bubbles of the ink composition. Specific examples of the acetylene glycol surfactant or acetylene alcohol surfactant preferable in the present invention include Surfynol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465. , 485, SE, SE-F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA (all are trade names, manufactured by Air Products and Chemicals), Olfin B, Y, P, A, STG SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP. 4001, EXP. 4036, EXP. 4051, AF-103, AF-104, AK-02, SK-14, AE-3 (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), acetylenol E00, E00P, E40, E100 (all trade names, Kawaken Fine Chemical Co., Ltd.). The addition amount of these acetylene glycol surfactants and acetylene alcohol surfactants may be appropriately determined, but is preferably 10% by weight or less based on the total amount of the coating liquid or the total amount of the ink composition.

  Another example of the penetrant includes a glycerin ether compound represented by the following formula.

  Any glycerin ether compound may be used as long as it has the structure of the above formula, among which 3-methoxy-1,2-propanediol, 3-ethoxy-1,2-propane, among others. Diol, 3-allyloxy-1,2-propanediol, 3- (octadecyloxy) -1,2-propanediol, monoolein, 1,2-dihydroxy-3- (2-methoxyphenoxy) propane, 3-phenoxy It is preferably selected from the group consisting of -1,2-propanediol. The addition amount of these glycerin ether compounds may be appropriately determined so that a desired effect can be exhibited, but is preferably 10% by weight or less based on the total amount of the coating liquid or the total amount of the ink composition according to the present invention.

  These penetrants may be used alone or in a mixture of two or more. In particular, when a plurality of penetrants having different structures are used in combination, the same penetrability can be obtained for various recording medium types exhibiting different penetrability / coloring properties, which is preferable from the viewpoint of compatibility with the recording medium type. .

[Antiseptic / antifungal agent]
The coating liquid and ink composition of the present invention preferably further contain an antiseptic / antifungal agent. The antiseptic / antifungal agent used in the present invention is preferably selected from the group consisting of isothiazolone compounds and oxazolidine compounds. If bacteria or wrinkles occur in the coating liquid or ink composition, they become foreign matter and clog the head nozzles or ink flow paths in the ink jet printer, adversely affecting the ejection of the coating liquid or ink composition. However, by including these antiseptic / antifungal agents, it is possible to more effectively suppress the generation of bacteria, wrinkles and the like even when left for a long period of time.

  The antiseptic / antifungal agent contained in the coating liquid and ink composition of the present invention can be contained in an amount of 1% by weight or less, preferably in the range of 50 ppm to 1% by weight, preferably 100 ppm to 0.5%. More preferably, it is in the range of% by weight.

  As the antiseptic / antifungal agent contained in the coating liquid and ink composition of the present invention, in detail, Proxel XL2, Proxel GXL (trade name, manufactured by Avisia), Denside CSA, NS-500W (trade name, Nagase) Chemtex Co., Ltd.). The antiseptic / antifungal agent may be used alone or in combination of two or more.

<Physical properties of coating liquid and ink composition>
The coating liquid and ink composition in the present invention preferably have a pH in the range of 6 to 11 at 25 ° C. More preferably, the pH is in the range of 7-10. When the pH is less than 6, the coating liquid may have poor coating properties on the recorded image, that is, the plasticizing / dissolving properties of the resin component may be deteriorated, resulting in poor gloss and fixing properties on the glossy media. is there. In addition, the ink composition may lack the dispersion stability of the dispersion, the surface-treated pigment, the resin emulsion, or the like, and may have adverse effects such as thickening, granulation, and sedimentation. If the pH is higher than 11, both the coating liquid and the ink composition have high reactivity with respect to the ink flow path member, which may cause deterioration of the member, generation of foreign matters, unstable ejection, and the like. In order to adjust the pH of the coating liquid and ink composition to the above range, a water-soluble basic substance can be used as necessary.

Specific examples of such basic substances include sodium hydroxide, potassium hydroxide and lithium hydroxide, ammonia, etc., carbonates such as potassium (hydrogen) potassium, sodium (hydrogen) carbonate, lithium (hydrogen) carbonate, and other phosphates. And inorganic alkalis.
In addition, salts of alkyl carboxylic acids such as acetate and propionate, organic acids such as hydroxy acid salts such as lactate, glycolate and glycerate, especially alkali metal salts of alkyl carboxylic acids, sodium acetate , Potassium acetate, sodium propionate, potassium propionate and the like. Moreover, organic buffer agents, such as a tris (hydroxymethyl) aminomethane, a tris-hydrochloride, a tris-maleic acid, bis (2-hydroxyethyl) imino tris (hydroxymethyl) methane, are mentioned. Moreover, various amine compounds can be mentioned. Preferred amine compounds include water-soluble volatile amines and alkanolamines. Specifically, a volatile amine substituted with an alkyl group (for example, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, diisopropylamine, butylamine, isobutylamine, sec- Butylamine, tert-butylamine, dibutylamine, diisobutylamine, pentylamine, etc.); alkanolamines substituted with alkanol groups (for example, 2-aminoethanol, 2- (dimethylamino) ethanol, 2- (diethylamino) ethanol, diethanolamine, N-butylethanolamine, triethanolamine, isopropanolamine, etc.); alkyl alkanol amino substituted with alkyl and alkanol groups Etc. The.

The coating liquid and ink composition of the present invention preferably have a surface tension at 25 ° C. of 40 mN / m or less. More preferably, it is 35 mN / m or less. When the surface tension is within the above range, the wettability with respect to the surface of an ink flow path member generally used in an ink jet printer is improved, and the discharge is easily stabilized. In order to adjust the surface tension within the above range, a surfactant may be used in addition to the above-described penetrant and others as necessary.
As surfactants, in addition to the above-mentioned acetylene glycol and acetylene alcohol surfactants as penetrants, general anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants A nonionic surfactant or an anionic surfactant is preferable. Nonionic surfactants include sorbitan fatty acid ester, glycerin fatty acid ester, decagrin fatty acid ester, polyglycerin fatty acid ester, propylene glycol / pentaerythritol fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycerin. Fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene / polyoxypropylene / block polymer, polyoxyethylene alkylphenyl ether, polyoxyethylene castor oil / cured castor oil , Polyoxyethylene lanolin / lanolin alcohol, polyoxyethylene alcohol Triethanolamine, fatty acid amides, there polyoxyethylene alkyl phenyl formaldehyde condensates, fluorine-based surfactants such as polyoxyethylene perfluoroalkyl the like. Anionic surfactants include alkyl sulfates, polyoxyethylene alkyl sulfates, N-acyl amino acids and their salts, N-acyl methyl taurates, dialkyl sulfosuccinates, disodium sulfosuccinate monoesters, N-alkyl sulfosuccinates. Examples include acid monoamides, polyoxyethylene alkyl ether acetates, alkyl sulfocarboxylates, α-olefin sulfonates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, and the like. As another function of these surfactants described above, when the plasticizer in the coating liquid is difficult to dissolve or does not dissolve in water, it also acts as a solubilizer / emulsifier, effectively in the coating liquid. It also has the property that it can be included.

  In addition, the viscosity of the coating liquid and ink composition in the present invention is preferably 25 cPs or less at 25 ° C. from the viewpoint of ensuring ejection stability in the ink jet recording apparatus. More preferably, it is 15 cPs or less.

<Method for producing dispersion>
Here, the manufacturing method of the dispersion used for the ink composition in the present invention will be described.
The dispersion used in the ink composition of the present invention is prepared by dissolving or dispersing a resin containing an anionic group in an alkaline water containing an alkaline compound such as an organic amine or an alkali metal salt compound. It is obtained by mixing and dispersing using a dispersing machine such as a ball mill, a sand mill, an attritor, a roll mill, an agitator mill, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a jet mill, or an ang mill. More preferably, in order to more firmly bond the colorant and the dispersion resin to stabilize the dispersion, JP-A Nos. 9-151342, 10-140065, 11-209672, and 11 -172180, JP-A-10-25440, JP-A-11-43636, or JP-A-2001-247810. The manufacturing methods disclosed in these publications are outlined below.

  Japanese Patent Laid-Open Nos. 2001-247810, 9-151342, and 10-140065 disclose a “phase inversion method” and an “acid precipitation method”.

a) "Phase inversion method"
In the present invention, the “phase inversion method” basically refers to a self-dispersion (phase inversion emulsification) method in which a mixed melt of a resin having a self-dispersing ability or a dissolving ability and a colorant is dispersed in water. Say. Here, the mixed melt means a mixed state without dissolving, a mixed state with dissolved, or a state including both of these states.
As one specific example, (1) a solvent-based slurry is prepared by adding a pigment, a neutralizing agent, and a small amount of water to a dispersion resin precursor (resin containing anionic group described above) / solvent solution. Step (2) Dispersing the slurry while adding it to a large amount of water to produce a water-based slurry, (3) Removing the solvent used to dissolve the resin from the water-based slurry and dispersing the water A step of preparing a pigment-containing resin particle dispersion including a pigment with a functional resin.

b) "Acid precipitation"
In the present invention, the “acid precipitation method” refers to preparing a water-containing cake composed of a resin and a colorant, and neutralizing a part of the unneutralized groups contained in the resin in the water-containing cake with a neutralizing agent. A method for producing a dispersion by adding together.
When the unneutralized group is an anionic acid group and the neutralizing agent is a basic compound, specifically, for example, (1) a resin and a pigment are dispersed in an alkaline aqueous medium, and A step of subjecting the resin to gelation by heat treatment as necessary, (2) a step of hydrophobizing the resin by making the pH neutral or acidic, and strongly fixing the resin to the pigment; and (3) A step of filtering and washing with water as necessary to obtain a water-containing cake; (4) Neutralizing part or all of the anionic groups contained in the resin in the water-containing cake with a basic compound Thereafter, a step of re-dispersing in an aqueous medium, and (5) a step of subjecting the resin to gelation by performing a heat treatment as necessary.

  More specific production methods of the above “phase inversion method” and “acid precipitation method” are the same as those disclosed in JP-A-9-151342 and JP-A-10-140065. Good.

Furthermore, JP-A-11-209672 and JP-A-11-172180 disclose a method for producing a dispersion. The outline of this production method basically comprises the following production steps.
(1) A resin having an anionic group or a solution obtained by dissolving it in an organic solvent and a neutral compound are mixed and neutralized; (2) A pigment is mixed with this mixed solution to form a suspension. Later, the pigment is dispersed by a disperser or the like to obtain a pigment dispersion, (3) if necessary, the solvent is distilled off, and (4) a resin having an anionic group by adding an acidic compound By coating the pigment with a resin having an anionic group, (5) filtering and washing with water if necessary, and (6) adding a basic compound to have an anionic group. Neutralizing the anionic group of the resin and dispersing it in an aqueous medium to obtain an aqueous dispersion.

  More specific methods for producing the dispersion shown above may be the same as those disclosed in JP-A-11-209672 and JP-A-11-172180.

<Method for producing surface-treated pigment>
Next, the manufacturing method of the surface treatment pigment used for the ink composition in this invention is demonstrated.
As a method for producing a surface-treated pigment, first, a step of surface-treating the pigment is performed. In this step, the surface treatment of the pigment (introduction of the above-described functional groups or salts thereof) is performed by mixing the pigment and the surface treatment agent in an aqueous or non-aqueous solvent, or by heating the mixture. To implement. After the surface treatment, the obtained reaction product is repeatedly washed with water, ultrafiltration, reverse osmosis, centrifugation and / or filtration to remove residual unreacted substances, reaction by-products, residual treatment agents, etc. Thus, a surface-treated pigment can be obtained.

  In addition, it is desirable that the pigment used in the surface treatment step is pulverized and atomized in advance before introducing the above-described functional group or a salt thereof. As a means for pulverizing the pigment, pulverization media such as zirconia beads, glass beads, and inorganic salts can be used, and wet pulverization or dry pulverization can be used. Examples of the pulverizer include an attritor, a ball mill, and a vibration mill. After the pulverization treatment, it is desirable to remove contaminant components generated from the pulverization media and the pulverizer by washing the pigment, ultrafiltration and the like. In particular, a pulverization treatment method (salt milling method) combining dry pulverization and an inorganic salt can be easily removed by washing with water because the contaminant component generated from the pulverization medium is a water-soluble inorganic salt.

Here, as an example of a method for producing a surface-treated pigment used in the ink composition of the present invention, an example of a method for producing a surface-treated pigment having a sulfonic acid group or a sulfinic acid group on the surface will be described below in more detail. To do.
First, in the step of surface-treating the pigment, a fine particulate or powdery pigment is placed in an aprotic solvent (for example, N-methyl-2-pyrrolidone or sulfolane) 3 to 200 times the amount of the pigment, The pigment is sized with a sulfonating agent. As the sulfonating agent, for example, sulfonated pyridine salt, sulfamic acid, amidosulfuric acid, fluorosulfuric acid, chlorosulfuric acid, sulfur trioxide, fuming sulfuric acid or sulfuric acid can be used alone or in combination of two or more. The treatment with the sulfonating agent can be performed under heating (about 60 ° C. to 200 ° C.) and under stirring, and the heating can be performed before or after the addition of the sulfonating agent.
After the sulfonation treatment, the aprotic solvent and the remaining sulfonating agent are removed from the obtained pigment slurry. The removal treatment can be carried out repeatedly by washing with water, ultrafiltration, reverse osmosis, centrifugation, and / or filtration. Moreover, the contaminant component mixed in the above-mentioned sizing and dispersing treatment and sulfonation treatment is also removed together with the aprotic solvent and the sulfonating agent.

The amount of the functional group introduced into the surface-treated pigment used in the ink composition of the present invention is preferably 10 × 10 ⁻⁶ equivalents or more, more preferably 15 × 10 ⁻⁶ equivalents or more per 1 g of pigment particles. If the amount of functional groups introduced is less than 5 × 10 ⁻⁶ equivalents per gram of pigment particles, aggregation of dispersed pigment particles and the like occur, and the viscosity and dispersion of the dispersion / aqueous ink composition are increased. In some cases, the storage stability of the pigment dispersion or the water-based ink composition may decrease due to, for example, an increase in the particle size of the pigment particles. For example, when the functional group is a sulfonic acid group or a sulfinic acid group, the pigment aqueous dispersion is treated by an oxygen flask combustion method and absorbed in an aqueous hydrogen peroxide solution. It can be measured by quantifying sulfate ions (divalent) by ion chromatography and converting them to sulfonic acid groups and sulfinic acid groups.

  The zeta potential of the surface-treated pigment particles used in the ink composition of the present invention is a dilution obtained by diluting the surface-treated pigment particles with ion-exchanged water so that the pigment concentration is 0.001 wt% to 0.01 wt%. The absolute value of the zeta potential of the pigment particles at 20 ° C. and pH 8 to pH 9 when measured as a liquid is preferably 30 mV or more. More preferably, it is 40 mV or more, and an even more preferable absolute value of the zeta potential is 50 mV or more. When the absolute value of the zeta potential of the pigment particles is 20 mV or less, the storage stability of the pigment dispersion or water-based ink composition is reduced as in the case where the amount of the dispersibility-imparting group introduced is insufficient.

[Method for producing dispersion of surface-treated pigment]
In the ink composition of the present invention, the surface-treated pigment can be used as it is in the ink composition, but it is preferable to use it in the form of a pigment dispersion described below because it is easy to handle.

In the production of the pigment dispersion, first, the surface-treated pigment obtained in the above-described surface treatment step of the pigment, or the slurry of the surface-treated pigment, the wet cake, etc., has a pigment concentration (weight of about 5% to 50% by weight. Add to the aqueous medium (especially ion-exchanged water or distilled water) together with a neutralizing agent as necessary. Subsequently, a surface-treated pigment dispersion can be obtained by dispersing the pigment particles in an aqueous medium by applying an appropriate shearing force using a stirrer or a dispersing device.
In the dispersing step, it is preferable to add a small amount of the above-mentioned penetrating agent or surfactant to disperse. The reason for this is that these penetrants and surfactants have the effect that the pigment particles are easily adapted (wet easily) to the aqueous medium, and the contact resistance between the pigment particles in the aqueous medium and between the pigment and the dispersion medium is reduced. This is because it is effective to increase the dispersion efficiency. As a result, the shearing conditions of the apparatus in the dispersion treatment step can be relaxed (the shear force applied from the apparatus to the pigment dispersion can be reduced), and the time required for the dispersion treatment can be shortened. In such a case, the contamination component (particularly polyvalent metal ions such as Si, Ca, Mg, Fe, Cr, Ni, etc.) due to the dispersion media and the dispersion device is reduced. There is an effect that the dispersion stability and storage stability of the used ink composition are improved. These penetrants and surfactants only need to be mixed with at least the pigment in the dispersion step, and the timing of addition to the pigment may be before the dispersion step or during the dispersion step.

  Examples of the apparatus that can be used in the dispersion treatment include a stirrer, paint shaker, ball mill, sand mill, roll mill, speed line mill, homomixer, ultrasonic homogenizer, nanomizer, and microfluidizer.

  The neutralizing agent is added to dissociate the salt-forming group of the functional group on the surface of the surface-treated pigment, and the above-mentioned water-soluble basic substances can be suitably used.

The above-described pigment surface treatment step and this surface treatment pigment dispersion step may be carried out continuously. In particular, when the surface treatment of the pigment is carried out with an aqueous solvent, the reaction solvent in the surface treatment step and the dispersion medium in the dispersion step can be made the same aqueous system, so that it is easy to assemble continuous steps. However, the removal of residual unreacted substances, reaction by-products and the like in the surface treatment step is easier to obtain a pigment dispersion having better final dispersion stability if carried out before the dispersion step. On the other hand, when the solvent in the surface treatment step is a non-aqueous solvent, it may be easier to separate and remove residual unreacted substances from the target surface-treated pigment.
<Example>

  The image forming method of the present invention will be described in detail below, but the present invention is not limited to these examples. Prior to this, the coating liquid and ink composition to be used were prepared by the following materials and methods.

<Preparation of coating solution>
Coating solutions were prepared with the compositions shown in Tables 1 and 2. Each coating solution was used for each of the following evaluations after sufficiently stirring and mixing the respective materials and performing pressure filtration at a pressure of ² kg / cm ² using a membrane filter having a pore size of 1 μm.

<Preparation of ink composition>
Hereinafter, the preparation of the ink composition in the invention will be described. First, preparation examples of Dispersion 1 to Dispersion 4 containing the dispersion will be described.

(1) Dispersion 1
MA100 which is carbon black as a pigment (trade name, manufactured by Mitsubishi Chemical Co., Ltd.); 75 g, Jonkrill 611 of a styrene-acrylic acid resin having a carboxylic acid group as an anionic group as a dispersion resin (trade name, BASF Japan Ltd.) Manufactured, weight average molecular weight 8,100, acid value 53 KOH mg / g); 25 g, potassium hydroxide as an alkaline compound; 0.75 g, ultrapure water purified by ion exchange method and reverse osmosis method; 250 g mixed, zirconia Dispersion was carried out for 10 hours by a ball mill using beads. The obtained dispersion liquid was filtered through a membrane filter (trade name, manufactured by Nihon Millipore Limited) having a pore size of about 8 μm to remove coarse particles, and diluted with ultrapure water to a pigment concentration of 15% by weight to prepare dispersion 1. .

(2) Dispersion 2
For dispersion 1, the pigment is an organic pigment such as C.I. I. Dispersion 2 was prepared in the same manner except that it was changed to Pigment Yellow 74 and the addition amount was changed to 75 g.

(3) Dispersion 3
C. which is an organic pigment as a pigment. I. Pigment Blue 15: 4 (75 g), a styrene-acrylic acid resin Jonkril 678 having a carboxylic acid group as an anionic group as a dispersion resin (trade name, manufactured by BASF Japan Ltd., weight average molecular weight 8,500, acid value 215 KOHmg / G) is 75 g, potassium hydroxide is 9.4 g as an alkaline compound, and 250 g of ultrapure water purified by an ion exchange method and a reverse osmosis method is used, and each is mixed and dispersed for 10 hours in a ball mill with zirconia beads. went. The obtained dispersion stock solution is filtered through a membrane filter having a pore diameter of about 8 μm (trade name, manufactured by Nippon Millipore Limited) to remove coarse particles, diluted with ultrapure water to a pigment concentration of 15% by weight, and C, which is an organic pigment. . I. Dispersion 3 was prepared by dispersing Pigment Blue 15: 4 with a dispersion resin.

(4) Dispersion 4
[Synthesis of dispersion resin]
1-L beaker was mixed with n-butyl methacrylate; 200 g, n-butyl acrylate; 25 g, styrene; 100 g, 2-hydroxyethyl methacrylate; 75 g, methacrylic acid; 100 g, and tert-butyl peroxyoctoate as a polymerization initiator; 4 g was added to prepare a resin synthesis mixture.
Next, 500 g of methyl ethyl ketone was placed in a 1 L flask, and the temperature was raised to 75 ° C. with stirring in a nitrogen atmosphere. The resin synthesis mixture was mixed dropwise over 3 hours with stirring. After completion of the dropwise addition, the reaction was further continued at 75 ° C. with stirring for 8 hours. Thereafter, the reaction product was naturally cooled to 25 ° C., and diluted by adding methyl ethyl ketone so that the solid content was 50% by weight. A dispersion resin A solution having an acid value of 150 KOH mg / g and a weight average molecular weight of 15,000 was prepared.
[Preparation of dispersion]
C. which is an organic pigment as a pigment. I. 150 g of Pigment Violet 19, 100 g of the above dispersion resin A solution, 50 g of potassium hydroxide (10% by weight aqueous solution) as an alkaline compound, 700 g of ultrapure water purified by an ion exchange method and a reverse osmosis method, and mixing them. Then, in a sand mill (manufactured by Yasukawa Seisakusho), the mixture was dispersed for 2 hours together with glass beads (diameter 1.7 mm, 1.5 times the weight (weight) of the mixture). Thereafter, the glass beads were removed, and the mixture was stirred at room temperature for 20 minutes, and then filtered through a 5 μm membrane filter.
The obtained filtrate was distilled at 80 ° C. under normal pressure to remove all of methyl ethyl ketone and a part of water. Further, 1N hydrochloric acid solution was added dropwise with stirring to coagulate the dispersed resin layer. This was subjected to suction filtration while washing with water to obtain a water-containing pigment cake. The water-containing cake was gradually added to stirred potassium hydroxide (1 wt% aqueous solution); 422 g, and stirred and mixed to redisperse. Further, ultrapure water was added so that the pigment concentration was 15% by weight to prepare dispersion 4.

  Next, a method for producing a surface-treated pigment and preparation examples of dispersions 5 to 8 containing the same will be described.

[Preparation of surface-treated pigment and preparation of dispersion]
(1) Preparation of surface-treated pigment 1 and preparation of dispersion 5; carbon black 15 parts of MA-7 (trade name, manufactured by Mitsubishi Chemical Corporation), which is carbon black as a pigment, was mixed in 200 parts of sulfolane, and Eiger Motor In Mill M250 type (trade name, manufactured by Eiger Japan), dispersed for 1 hour under the conditions of 70% bead filling and 5,000 rpm, and the dispersed pigment paste and solvent mixture was transferred to an evaporator, 30 mmHg or less While reducing the pressure to 120 ° C., the water contained in the system was distilled as much as possible, and then the temperature was controlled at 150 ° C.
Next, 25 parts of sulfur trioxide was added and reacted for 6 hours. After completion of the reaction, the resin was washed several times with excess sulfolane, poured into water, and filtered to remove functional groups such as sulfinic acid groups or sulfonic acid groups. A slurry of the surface-treated pigment 1 introduced directly on the surface was obtained.
20 parts of the surface-treated pigment 1 (carbon black) prepared above, 3 parts of triethanolamine as a neutralizing agent, and 77 parts of ion-exchanged water are mixed, and a paint shaker (using glass beads; bead filling ratio 60%; media diameter) 1.7 mm) was used to disperse the pigment until the average particle size (secondary particle size) of the pigment reached 100 nm, thereby preparing a dispersion 5 having a pigment concentration of 20% by weight.

(2) Preparation of surface-treated pigment 2 and preparation of dispersion 6; I. Pigment Blue 15: 3
20 parts of phthalocyanine blue pigment (CI Pigment Blue 15: 3), an organic pigment, is mixed with 500 parts of quinoline as a pigment, and a bead filling rate of 70% with an Eiger motor mill M250 type (trade name, manufactured by Eiger Japan). And the dispersion of the pigment paste and the solvent dispersed for 2 hours under the condition of a rotational speed of 5,000 rpm, transferred to an evaporator and heated to 120 ° C. while reducing the pressure to 30 mmHg or less, so that the water contained in the system was retained as much as possible. After leaving, the temperature was controlled at 160 ° C. Next, 20 parts of a sulfonated pyridine complex is added and allowed to react for 8 hours. After completion of the reaction, it is washed several times with excess quinoline, poured into water and filtered to remove functional groups such as sulfinic acid groups or sulfonic acid groups. A slurry of the surface-treated pigment 2 introduced directly on the pigment surface was obtained.
20 parts of the surface-treated pigment 2 (CI Pigment Blue 15: 3) produced above, 2 parts of Surfynol 465 (trade name, manufactured by Air Products and Chemicals), an acetylene glycol surfactant that is a penetrant, As a neutralizing agent, 4 parts of triethanolamine and 74 parts of ion-exchanged water are mixed, and using a paint shaker (using glass beads; bead filling ratio 60%, media diameter 1.7 mm), the average particle diameter of the pigment ( Dispersion liquid 6 having a pigment concentration of 20% by weight was prepared by dispersing until the secondary particle diameter was 95 nm.

(3) Preparation of surface-treated pigment 3 and preparation of dispersion 7; I. Pigment Red 122
As a pigment, 20 parts of dimethylquinacridone pigment (CI Pigment Red 122), an organic pigment, is mixed with 500 parts of quinoline, and a bead filling rate of 70% and rotation with an Eiger Motor Mill M250 type (trade name, manufactured by Eiger Japan). Disperse for 2 hours under conditions of several 5,000 rpm, transfer the mixture of the pigment paste and solvent after dispersion to an evaporator, and heat to 120 ° C while reducing the pressure to 30 mmHg or less to distill off as much water as possible in the system. After that, the temperature was controlled at 160 ° C. Next, 20 parts of a sulfonated pyridine complex is added as a reactant and reacted for 4 hours. After completion of the reaction, the mixture is washed several times with excess quinoline, poured into water and filtered to obtain a functional group such as a sulfinic acid group or a sulfonic acid group. A slurry of the surface-treated pigment 3 was obtained in which the groups were directly introduced on the surface of the organic pigment.
20 parts of surface-treated pigment 3 (CI Pigment Red 122) produced above, 5 parts of Surfynol 465 (trade name, manufactured by Air Products and Chemicals), an acetylene glycol surfactant that is a penetrant, and a penetrant 10 parts of 1,2-hexanediol, 3 parts of an aqueous 30% ammonia solution as a neutralizing agent, and 62 parts of ion-exchanged water are mixed with a paint shaker (using glass beads; bead filling ratio 60%, media diameter 1.7 mm). ) Was used until the average particle size (secondary particle size) of the pigment reached 100 nm, whereby a dispersion 7 having a pigment concentration of 20% by weight was prepared.

(4) Preparation of surface-treated pigment 4 and preparation of dispersion 8; C. I. Pigment Yellow 128
20 parts of a condensed azo yellow pigment (CI Pigment Yellow 128), which is an organic pigment, is mixed with 500 parts of quinoline as a pigment, and an Eiger Motor Mill M250 type (trade name, manufactured by Eiger Japan) has a bead filling ratio of 70%. The mixture of the pigment paste and the solvent, which has been sized and dispersed for 2 hours at a rotational speed of 5,000 rpm, is transferred to an evaporator and heated to 120 ° C. while being reduced in pressure to 30 mmHg or less, and contained in the system. After removing water as much as possible, the temperature was controlled at 160 ° C. Next, 20 parts of a sulfonated pyridine complex is added as a reactant and allowed to react for 4 hours. After completion of the reaction, the mixture is washed several times with excess quinoline, poured into water, and filtered to obtain sulfinic acid groups or sulfonic acid groups. A slurry of the surface-treated pigment 4 in which the functional group was directly introduced on the surface of the organic pigment was obtained.
20 parts of the surface-treated pigment 4 (CI Pigment Yellow 128) prepared above, 1 part of Surfynol 104 (trade name, manufactured by Air Products and Chemicals), an acetylene glycol surfactant as a penetrant, and a penetrant 10 parts of triethylene glycol monobutyl ether, 1 part of potassium hydroxide as a neutralizing agent and 68 parts of ion-exchanged water are mixed, and a paint shaker (using glass beads; bead filling ratio 60%, media diameter 1.7 mm) is mixed. A dispersion 8 having a pigment concentration of 20% by weight was prepared by dispersing the pigment until the average particle size (secondary particle size) of the pigment reached 130 nm.

  Using the dispersions 1 to 8 obtained by the materials and methods described above, ink compositions having the compositions shown in Tables 3 and 4 were prepared. Each ink composition was used for each of the following evaluations after sufficiently stirring and mixing the respective materials and performing pressure filtration at a pressure of 2 kg / cm 2 using a membrane filter having a pore size of 1 μm.

  Using the coating liquid and ink composition prepared by the materials and methods described above, the following evaluations (recorded product evaluation, printer characteristic evaluation) were performed. Table 5 shows the combination of the coating liquid and the ink composition and the evaluation results at the time of evaluation. However, for Example 13, Example 14, Example 15, and Comparative Example 6, when performing the evaluation shown below, the four ink composition examples shown in Table 5 were combined to produce a single color or a secondary color. This was done by printing a full color image in which tertiary colors were mixed.

<Evaluation of recorded materials>
[Evaluation 1: Evaluation of glossiness on glossy media]
Using the coating liquid examples 1 to 18 and the ink composition examples 1 to 16 prepared as described above, the combinations shown in Table 5 were evaluated. First, ink composition example 1 to ink composition example 16 are mounted on an ink jet printer PX-A650 (trade name, manufactured by Seiko Epson Corporation), and images with different fill densities in 5% increments from 5% to 100% are used as glossy media. Printed on top. The print setting at this time was “paper type: EPSON photo paper, print quality: good”. Thereafter, coating liquid example 1 to coating liquid example 18 are mounted on the black cartridge portion of another ink jet printer PX-A650, and using this, on the recorded image printed in ink composition example 1 to ink composition example 16 earlier. An image filled with a coating solution was printed on the surface. The print setting at this time was “paper type; plain paper, print quality: fast”. The gloss of the recorded material thus recorded was evaluated. The glossy media used in this evaluation are (1) glossy paper, (2) photographic paper <gloss>, (Both (1) and (2) are trade names, manufactured by Seiko Epson Corporation), and (3) professional photo paper ( (Product name, manufactured by Canon Inc.), (4) Premium Plus Photo Paper (Gloss) (trade name, manufactured by Hured Packard), (5) Glossy Inkjet Photo Paper (Photolike QP) (Product Name, Konica Minolta Holdings, Inc.) Made by Co., Ltd.). Evaluation was made visually. The evaluation criteria are shown below. The evaluation results are shown in Table 5. Note that the parentheses shown for the recording medium type in Table 5 are the same as the parentheses attached to the glossy media names.
Evaluation A: Glossiness is recognized in all filled images.
Evaluation B: An image with a fill density of 100% is slightly glossy but has no practical problem.
Evaluation C: An image with a fill density of 50% or more lacks gloss.
Evaluation D: All painted images lack gloss.

[Evaluation 2: Evaluation of fixability on glossy media]
Using the coating liquid examples 1 to 18 and the ink composition examples 1 to 16 prepared as described above, the combinations shown in Table 5 were evaluated. First, ink composition examples 1 to 16 were mounted on an ink jet printer PX-A650 (trade name, manufactured by Seiko Epson Corporation), and 12-point Gothic character printing was performed on each. The print setting at this time was “paper type: EPSON photo paper, print quality: good”. Thereafter, coating liquid example 1 to coating liquid example 18 are mounted on the black cartridge portion of another ink jet printer PX-A650, and using this, on the recorded image printed in ink composition example 1 to ink composition example 16 earlier. An image filled with a coating solution was printed on the surface. The print setting at this time was “paper type; plain paper, print quality: fast”. Using the recorded matter thus recorded, the fixability was evaluated. The glossy media used in this evaluation was the same as that used in [(1) Evaluation of glossiness on glossy media]. Evaluation is carried out by visually observing the deviation or blurring of characters after rubbing with a finger using a recorded material that has been dried at 20 ° C. to 25 ° C./40% RH to 60% RH for 1 hour after printing. It was. The evaluation criteria are shown below. The evaluation results are shown in Table 5. The numbers in parentheses shown for the recording medium types in Table 5 are the same as those shown in [Evaluation 1: Evaluation of glossiness on glossy media].
Evaluation A: Misalignment and blurring are not recognized.
Evaluation B: A slight deviation is recognized, but there is no practical problem.
Evaluation C: Misalignment or blurring is observed.
Evaluation D: Misalignment and faintness are severe, and characters are difficult to read.

[Evaluation 3: Evaluation of image quality on plain paper / recycled paper]
Using the ink composition examples 1 to 16 prepared above, the ink composition printer PX-A650 (trade name, manufactured by Seiko Epson Corporation) was mounted. Image quality (character quality) due to character blurring when 1 to 20 points of Gothic characters are printed in 1 point increments on plain paper / recycled paper with the print setting “paper type; plain paper, print quality; fast” Evaluated. Furthermore, images with different fill densities were printed in 5% increments from 5% to 100% with the same print settings, and the image quality (filled image quality) due to shading unevenness of the recorded matter was evaluated. In this evaluation, as plain paper, (6) Xerox Business Multipurpose 4200 Paper (trade name, manufactured by Xerox Corporation), (7) Xerox P (trade name, manufactured by Fuji Xerox Office Supply Co., Ltd.), (8) Hammermill Copy Plus ( (9) Xerox R (trade name, manufactured by Fuji Xerox Office Supply Co., Ltd.) was used as the recycled paper, and the evaluation was performed visually. The evaluation criteria are shown below. The evaluation results are shown in Table 5. Note that the parenthesis numerals shown for the recording medium types in Table 5 are the same as the parenthesis numerals attached to the names of the above-mentioned plain paper and recycled paper.
[Character quality]
Evaluation A: No blur is seen in the characters at all points.
Evaluation B: Slight bleeding is observed with characters of 5 points or less (practical level).
Evaluation C: Characters of 5 points or less appear thick due to bleeding.
Evaluation D: Bleeding is remarkable and characters of 5 points or less cannot be distinguished.
[Filled image quality]
Evaluation A: Light and shade unevenness is hardly recognized in all filled images.
Evaluation B: Slight shading unevenness is recognized in an image with a fill density of 100% (practical level).
Evaluation C: Density unevenness is observed in an image having a fill density of 50% or more.
Evaluation D: Light and shade unevenness is observed in all filled images.

<Printer characteristic evaluation>
[Evaluation 4: Clogging evaluation]
Using the coating liquid examples 1 to 18 and the ink composition examples 1 to 16 prepared as described above, they were mounted on an inkjet printer PX-A650 (trade name, manufactured by Seiko Epson Corporation), respectively. Thereafter, the printer was left in a 60 ° C. environment for one week in a state where the coating liquid example and the ink composition example were filled. After returning the printer to room temperature after standing, premium plus photo paper (gloss) (trade name, manufactured by Hured Packard) is used as a recording medium, and 20 ° C / -25 ° C / 40% RH-60% RH. Filled image printing was continuously performed in an environment, and clogging was determined based on the following criteria based on conditions such as missing dots and bent dots. The print setting was “paper type; plain paper, print quality: fast”. The evaluation criteria are shown below. The evaluation results are shown in Table 5.
Evaluation A: Clogging such as bent dots and missing dots does not occur immediately after the start of continuous printing.
Evaluation B: The clogging is eliminated by performing the cleaning operation of the printer within two times.
Evaluation C: The clogging is eliminated by performing the cleaning operation of the printer 3 to 5 times.
Evaluation D: The printer needs to be cleaned six times or more to eliminate clogging, or clogging is not eliminated.

[Evaluation 5: Evaluation of ejection stability]
Using the coating liquid examples 1 to 18 and the ink composition examples 1 to 16 prepared as described above, they were mounted on an inkjet printer PX-A650 (trade name, manufactured by Seiko Epson Corporation), respectively. Premium plus photo paper (gloss) (trade name, manufactured by Hured Packard) is used as the recording medium, and images with mixed text and fills are used in an environment of 20 ° C / -25 ° C / 40% RH-60% RH. The images were printed continuously, and the presence or absence of defects such as bent dots and missing dots in the image was visually measured. The print setting was “paper type; plain paper, print quality: fast”. The evaluation criteria are shown below. The evaluation results are shown in Table 5.
Evaluation A: Even when continuous printing is performed up to 200 sheets, dot bending and dot missing do not occur.
Evaluation B: In continuous printing up to 100 sheets, dot bending and dot missing do not occur.
Evaluation C: In continuous printing up to 100 sheets, dot bending / dot missing occurred but there were less than 10 points.
Evaluation D: At the time of continuous printing up to 100 sheets, 10 or more dots are bent or missing.

  As is apparent from Table 5, in the image forming method of the present invention, that is, the image forming method of applying a coating liquid to the recorded image, the coating liquid comprising at least water, a plasticizer and a humectant, and the recorded image is In Examples 1 to 15 according to the image forming method recorded with an ink composition containing at least a resin component and a pigment, the paper is excellent in glossiness and fixability on glossy media such as glossy paper, and is plain paper. -A high-quality and clear recorded matter that oozes on recycled paper and has little unevenness in density was obtained. Further, in the coating liquid examples 1 to 15 and the ink composition examples 1 to 12 used in Examples 1 to 15, the printer characteristics (clogging property and ejection stability) were good. In particular, in Examples 13 to 15, in addition to the above evaluation, a full color image was printed using a photograph image of a person and a landscape. However, similar to the above evaluation, glossiness / fixing on glossy media such as glossy paper was performed. High quality and clear recordings with excellent properties, bleeding on plain paper and recycled paper, and less uneven density were obtained.

  On the other hand, in Comparative Example 1, since the coating liquid to which the plasticizer according to the present invention was not added (Coating Liquid Example 16) was used, both glossiness and fixing property on the glossy media were poor. Further, in Comparative Example 2, since the coating liquid (Coating liquid example 17) in which the plasticizer and the humectant were not used together was used, the printer characteristics (clogging property and ejection stability) were poor. In Comparative Example 3, the coating liquid based on JP-A-2005-81754 was used, but both glossiness and fixability on glossy media were satisfied despite the addition of a water-soluble resin. In addition, the printer characteristics (clogging and ejection stability) of the coating liquid were not satisfactory. In Comparative Example 4 and Comparative Example 5, since no coating liquid was used during image formation, the image quality on plain paper and recycled paper and the printer characteristics (clogging property, ejection stability) of the ink composition were not a problem. Both glossiness and fixability on glossy media were poor. Further, in Comparative Example 6, since the ink composition containing no resin component (Ink Composition Examples 13 to 16) was used, the image quality and the printer characteristics (clogging property, ejection stability) on plain paper / recycled paper were used. Although there was no problem, glossiness and fixability on glossy media were both poor.

  As described above, in the image forming method according to the present invention, that is, the image forming method for applying a coating liquid to a recorded image, the coating liquid containing at least water, a plasticizer, and a humectant, and the recorded image is at least a resin In an image forming method recorded with an ink composition comprising a component and a pigment, the coating solution used does not contain an oil-soluble or volatile solvent. Can be handled without problems, and images with excellent fixability and glossiness can be obtained even on recorded images on glossy media with ink compositions containing pigments. Furthermore, ejection stability and clogging are also possible in the inkjet recording method. Is excellent. Further, as a dispersant for dispersing the pigment in the component in the ink composition to be used, an unneutralized group comprising a hydrophobic part and a hydrophilic part, at least a part of the hydrophilic part being a part of the hydrophobic part A neutralizing group obtained by neutralizing a dispersion resin, wherein the abundance of the neutralizing group is in the range of 20% or more and less than 60% in molar ratio to the sum of the unneutralized group and the neutralized group And / or when a resin emulsion made of a resin having a glass transition temperature of 30 ° C. or higher is used, even on plain paper and recycled paper, a high-quality and clear image with little bleeding, shading unevenness, etc. It also has the effect of being obtained.

  The present invention should not be considered to be limited to these examples, and various modifications can be made without departing from the gist of the present invention.

Claims (11)

  In an image forming method for applying a coating liquid to a recorded image, a plasticizer and a humectant for dissolving or plasticizing the resin component on a recorded image recorded with an ink composition comprising at least a resin component, a pigment, and water An image forming method comprising coating with a coating solution containing water and water.   The plasticizer contained in the coating liquid is phthalic acid esters, trimellitic acid esters, aliphatic dibasic acid esters, orthophosphoric acid esters, ricinoleic acid esters, polyesters, epoxidized esters, acetate esters. The image forming method according to claim 1, wherein the image forming method is one or two or more selected from the group consisting of catechol and sulfonamides.   The image forming method according to claim 1, wherein the coating liquid and / or the ink composition further contains a penetrating agent. The pigment contained in the ink composition is surface-treated so as to directly or indirectly bond at least one of the functional group represented by the following formula or a salt thereof to the surface thereof, and can be dispersed in water without a dispersant. The image forming method according to claim 1, wherein the image forming method is performed.

  The image forming method according to claim 1, wherein the resin component contained in the ink composition is contained as a dispersion resin that disperses at least a pigment.   The dispersion resin consists of a hydrophobic part and a hydrophilic part, and at least a part of the hydrophilic part is a neutralizing group obtained by neutralizing an unneutralized group that is a part of the hydrophobic part, 6. The image forming method according to claim 5, wherein the abundance of the neutralizing group is in a range of 20% or more and less than 60% in molar ratio with respect to the sum of the unneutralized group and the neutralized group.   6. The image forming method according to claim 1, wherein the resin component contained in the ink composition is contained at least as a resin emulsion.   The image forming method according to claim 7, wherein a glass transition temperature (Tg) of a resin constituting the resin emulsion is 30 ° C. or higher.   The image forming method according to claim 1, wherein the coating liquid is applied to at least a recorded image portion on a recording medium by an inkjet head to perform coating.   The image forming method according to claim 1, wherein the recorded image to be coated is formed by ejecting the ink composition onto a recording medium with an inkjet head. .   A recorded matter recorded using the image forming method according to claim 1.