JP2007154016A - Ink set for inkjet and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink for inkjet having variety to recording media, in which feathering and bleeding are prevented, having adhesion to a substrate and high printing quality, an ink set for inkjet in which high-definition image free from stripe of a solid part and banding is obtained even when using a film not having ink-absorbing property and a recording medium having low lightness and to provide an inkjet recording method using the ink set. <P>SOLUTION: In the ink set for inkjet composed of a color ink and white ink and containing at least coloring agent, water and a polymer compound having a plurality of side chains on a hydrophilic main chain and enabling cross linking between side chains by irradiating active energy beam, surface tension of the white ink is controlled so as to be higher than that of the color ink. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink for ink jet and an ink jet recording method using the same, and beading is performed on a medium having good feathering when recording on plain paper and having little ink absorbability or no ink absorbability. The present invention relates to an inkjet ink suitable for recording without color bleeding or the like, and an inkjet recording method using the same.

  The ink jet recording method is capable of recording high-definition images with a relatively simple apparatus, and has been rapidly developed in various fields. In addition, there are various uses, and a recording medium or ink suitable for each purpose is used.

  In particular, in recent years, the recording speed has been greatly improved, and printers having performance capable of withstanding light printing applications have been developed.

  However, in order to bring out the performance of the ink jet printer, an ink jet special paper provided with ink absorbability is required.

  When recording on coated paper or art paper that does not absorb much ink, or on plastic film that does not absorb ink at all, there are problems such as so-called bleed that cause different color ink liquids to mix on the recording medium and cause color turbidity. However, it has been a problem in providing a variety of recording media to inkjet.

  In the above problems, a hot-melt ink composition made of a wax that is solid at room temperature is used, liquefied by heating, etc., sprayed with some energy applied, cooled and solidified while adhering to the recording medium, and recorded A hot-melt ink jet recording method for forming dots has been proposed.

  Since this ink is solid at room temperature, it does not get dirty during handling, and there is no substantial amount of ink evaporation at the time of melting, so there is no clogging of the nozzles. Furthermore, an ink composition has been proposed that solidifies immediately after adhering and has less color bleeding and provides good print quality regardless of paper quality (see Patent Documents 1 and 2).

  However, an image recorded by such a method has problems such as deterioration in quality due to the rising of the dots and lack of scratching performance because the ink dots are in the form of soft wax.

  On the other hand, an inkjet recording ink that is cured by exposure to ultraviolet rays has been disclosed (see Patent Document 3). In addition, a so-called non-aqueous ink containing a pigment as an essential component and a triacrylate or higher polyacrylate as a polymerizable material and using a ketone or an alcohol as a main solvent has been proposed (Patent Document 4). reference).

  Further, an ink using an aqueous ultraviolet polymerization monomer has been proposed (see Patent Document 5).

  In these methods, since the ink itself is cured with a curing component, recording is possible even on a non-absorbing medium. However, since the curing component other than the colorant is contained in a large amount and does not volatilize, the recording surface is reduced. The ink dots swelled up, causing unnaturalness in image quality, especially gloss.

  Furthermore, there is a safety concern for conventionally known curing components, and there is a problem that even if safety is cleared, there is a narrow selection of substances and it is not possible to design materials and physical properties freely.

  By the way, as a method of forming a reflection image on a transparent recording medium (base material), when printing using white ink and color ink, first, a white background is formed on a transparent base material with white ink, and then yellow, magenta Create an image with color inks such as cyan, black, etc., and print the final image from the print side. “Print” and overlay the white ink on the transparent substrate after forming the color ink on the transparent substrate. There is a method called “back printing” viewed through a substrate.

  It is possible to produce these images in the same manner by using white ink and color ink even in the ink jet recording method, and the white ink for ink jet has good visibility for a transparent recording medium or a recording medium with low brightness. In particular, when used in combination with color ink, it is an effective method capable of obtaining a clear full-color image similar to that when recording on a white medium.

  In that case, in the ink jet recording method for producing an image with dots, in order to produce a higher-definition image, the color ink needs to maintain a dot size that matches the resolution on the substrate. In particular, when color ink is placed on white ink such as surface printing, the dot diameter of the color ink depends on the characteristics of the white ink. If the dot diameter of the color ink becomes smaller than the dot size that matches the resolution, a gap is generated between the dots, resulting in an image defect.

On the other hand, an ultraviolet curable ink composition comprising a colorant (coloring material), an ultraviolet curing agent, a photopolymerization initiator, and the like as an inkjet ink that can be fixed and printed on a recording medium such as a film or metal that does not absorb ink There is a thing. There has been proposed an ultraviolet curable inkjet white ink using titanium oxide, which is a white pigment, as these colorants (see, for example, Patent Documents 6 and 7). However, these are not assumed to be used in combination with color inks, and there is no description regarding an optimal combination for obtaining a clear and clear full-color image using white ink and color ink.
US Pat. No. 4,391,369 U.S. Pat. No. 4,484,948 U.S. Pat. No. 4,228,438 Japanese Patent Publication No. 5-64667 JP-A-7-224241 JP 2000-336295 A (Claims) JP 2001-207098 A (Example)

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a variety of recording media, prevent feathering and bleeding, and have high adhesion to a substrate and high print quality. Is to provide ink for use.

  Furthermore, by providing an ink-jet ink set and an ink-jet recording method using the same, which can obtain a high-definition image without solid streaks or banding even on a film having no ink absorption or a recording medium having low brightness. is there.

  The above object of the present invention can be achieved by the following constitution.

  1. A color ink containing at least a colorant, water, a polymer compound having a plurality of side chains in a hydrophilic main chain and capable of crosslinking between side chains by irradiation with active energy rays; An ink-jet ink set comprising an ink, wherein the white ink has a surface tension higher than that of the color ink.

  2. After the white ink described in 1 is jetted onto the recording medium by an ink jet recording apparatus and cured by irradiating active energy rays, the color ink described in 1 is applied on the white ink layer on the recording medium. An ink jet recording method comprising: forming an image by spraying from an ink and irradiating an active energy ray to cure.

  3. 3. The inkjet ink set according to 1 or 2, wherein the white ink has a surface tension of 0.5 to 5 mN / m higher than that of the color ink having the highest surface tension.

  4). The ink set for inkjet according to any one of 1 to 3, wherein the white ink contains titanium oxide as a colorant.

  5. The ink set for inkjet according to any one of 1 to 4, wherein the color ink and the white ink have a surface tension of 20 to 60 mN / m.

  6). The ink set for inkjet according to any one of 1 to 5, wherein the polymer compound is contained in an amount of 0.8 to 5.0% by mass based on the total mass of the ink.

  7). The inkjet according to any one of 1 to 6, wherein the hydrophilic main chain is a saponified product of polyvinyl acetate, has a saponification degree of 77 to 99%, and a polymerization degree of 200 to 4000. Ink set.

  8). The inkjet ink set according to any one of 1 to 7, wherein a modification rate of the side chain with respect to the hydrophilic main chain is 0.8 mol% or more and 4 mol% or less.

  9. An image forming method in which ink is ejected onto a recording medium from the ink jet recording head using the ink jet ink set according to any one of 1 to 8, and printing is performed on the recording medium. After that, an actinic ray is irradiated for 0.001 to 1.0 seconds.

  10. An inkjet recording method comprising: discharging an inkjet ink set according to any one of 1 to 8 onto a recording medium from an inkjet recording head; irradiating with an active energy ray;

  According to the present invention, it is possible to provide an ink-jet ink having a variety of recording media, preventing feathering and bleeding, having high adhesion to a substrate and high printing quality.

  Furthermore, it is possible to provide an ink-jet ink set capable of obtaining a high-definition image without solid streaks or banding even on a film having no ink absorbability or a recording medium having low brightness, and an ink-jet recording method using the same. it can.

  Hereinafter, although the best mode for carrying out the present invention will be described, the present invention is not limited to these.

  The present invention will be described in detail below.

  The ink set for ink jet comprising the color ink and the white ink of the present invention has at least a colorant, water, and a plurality of side chains in the hydrophilic main chain, and is irradiated with active energy rays between the side chains. A polymer compound that can be crosslinked is contained, but the polymer compound used in the present invention has high curing sensitivity and a small amount is sufficient, and most of the ink is composed of a dry component such as water. Dots do not rise, and the image quality surface is smooth and can provide an image with excellent gloss.

  In addition, for a film having no ink absorption or a recording medium with low brightness, after white ink is first discharged and cured on the recording medium, the color ink is discharged and printed on the white ink layer and cured. This is an effective method having good visibility and capable of obtaining a clear full-color image similar to that when recording on a white medium. At this time, when the surface tension of the white ink is lower than the surface tension of the color ink, if the color ink is placed on the white ink, the wettability of the ink droplets is poor and the dots are not filled, resulting in an image defect. In the ink containing the polymer compound capable of cross-linking between side chains by irradiating with active energy rays of the present invention, the white ink has a surface tension higher than that of the color ink. When printing color ink on top, the color ink dot wettability is improved and landing with the optimal dot diameter according to the resolution of the color ink, so there is no streak or banding in the solid part It has been found that an image can be obtained and has reached the present invention.

  Furthermore, the curing sensitivity when irradiated with active energy rays after color ink printing is further enhanced by the reflection of the active energy rays by the white ink layer, which can be applied to high-speed printing such as a line head. found.

[Ink surface tension]
The surface tension value of the ink defined in the present invention is a static surface tension value (mN / m) at a temperature of 25 ° C. by a platinum plate method using a surface tension meter (for example, CBVP-Z, manufactured by Kyowa Interface Science). Can be sought. The surface tension value of the ink cured by irradiation with actinic rays was determined by measuring the contact angles of water, methylene iodide and nitromethane on the ink image surface after curing, and then the Journal of the Adhesion Society of Japan, Vol. 8, page 131. The solid surface tension value (mN / m) of the ink image can be obtained by calculation according to the calculation formula described in (1972).

  In the present invention, there is no particular limitation as a means for setting the surface tension of the ink before emission defined above and the surface tension of the ink cured by irradiation with actinic rays as defined in the present invention. It can be realized by appropriately adjusting the type and addition amount, or the type and addition amount of the pigment dispersant described above, the type and addition amount of the polymerizable component, and the type and addition amount of the polymerization initiator.

  The surface tension of the color ink and the white ink of the present invention is preferably adjusted to 20 to 60 mN / m, particularly preferably 25 to 45 mN / m for color ink and 30 to 50 mN / m for white ink.

  If the surface tension is less than 20 mN / m, the ink tends to wet and spread to the tip surface of the discharge nozzle of the inkjet head, which may cause bending of output, satellite (minute extra droplets), or nozzle missing. There is. On the other hand, if it is larger than 60 mN / m, the surface tension value of the recording medium, particularly a film having no ink absorption or a recording medium with low lightness, is low, so that the contact angle of the ink droplet is increased and the wettability to the recording medium is increased. Poor, adhesion and adhesion may deteriorate.

  In the present invention, the surface tension of the white ink is preferably 0.5 to 5 mN / m higher than the ink having the highest surface tension among the color inks. If it is less than 0.5 mN / m, the surface tension of the color ink is almost equal to the surface tension of the white ink, and the wet tension of the ink on the solid surface becomes small. The wettability may become worse. On the other hand, if it is greater than 5 mN / m, the wet tension of the ink on the solid surface becomes large, so that the contact angle with the solid surface becomes too small and the wetting spread becomes larger than necessary and the dot diameter of the color ink. May become larger than the dot size according to the resolution, and a high-definition image may not be obtained.

<Active energy ray crosslinkable polymer compound>
The polymer compound having a plurality of side chains in the hydrophilic main chain according to the present invention and capable of crosslinking between the side chains by irradiating with active energy rays is a saponified product of polyvinyl acetate, polyvinyl acetal, polyethylene Oxide, polyalkylene oxide, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose, or a derivative of the hydrophilic resin, and at least one hydrophilic selected from the group consisting of these copolymers In the resin, a modified group such as a photodimerization type, a photodecomposition type, a photopolymerization type, a photomodification type, or a photodepolymerization type is introduced into the side chain. Photopolymerizable crosslinkable groups are desirable from the viewpoints of sensitivity and performance of the generated image.

  In the hydrophilic main chain, a saponified product of polyvinyl acetate is preferable from the viewpoint of ease of introduction of side chains and handling, and the polymerization degree is preferably 200 or more and 4000 or less, and 200 or more and 2000 or less is more preferable from the viewpoint of handling. preferable. The modification rate of the side chain with respect to the main chain is preferably 0.3 mol% or more and 4 mol% or less, and more preferably 0.8 mol% or more and 4 mol% or less from the viewpoint of reactivity. If it is less than 0.3 mol%, the crosslinkability is insufficient and the effect of the present invention is reduced. If it is more than 4 mol%, the crosslink density is increased and the film is hard and brittle, and the strength of the film is lowered.

  As the photodimerization-type modifying group, those in which a diazo group, a cinnamoyl group, a stilbazonium group, a stilquinolium group or the like is introduced are preferable. For example, a photosensitive resin described in JP-A-60-129742 (Composition).

  The photosensitive resin described in JP-A-60-129742 is a compound represented by the following general formula (1) in which a stilbazonium group is introduced into a polyvinyl alcohol structure.

In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms, and A ⁻ represents a counter anion.

  The photosensitive resin described in JP-A-56-67309 includes a 2-azido-5-nitrophenylcarbonyloxyethylene structure represented by the following general formula (2) in the polyvinyl alcohol structure, or the following general formula. This is a resin composition represented by (3) and having a 4-azido-3-nitrophenylcarbonyloxyethylene structure.

  Further, a modifying group represented by the following general formula (4) is also preferably used.

  In the formula, R represents an alkylene group or an aromatic ring. A benzene ring is preferred.

  As the photopolymerization type modifying group, for example, a resin represented by the following general formula (5) shown in JP-A Nos. 2000-181062 and 2004-189841 is preferable from the viewpoint of reactivity.

In the formula, R ₂ represents a methyl group or a hydrogen atom, n represents 1 or 2, X represents — (CH ₂ ) _m —COO— or —O—, and Y represents an aromatic ring or a single bond. And m represents an integer from 0 to 6.

  Moreover, it is also preferable to use the photopolymerization type | mold modified group represented by following General formula (6) described in Unexamined-Japanese-Patent No. 2004-161942 for a conventionally well-known water-soluble resin.

In the formula, R ₃ represents a methyl group or a hydrogen atom, and R ₄ represents a linear or branched alkylene group having 2 to 10 carbon atoms.

  Such an active energy ray-crosslinking resin is preferably contained in an amount of 0.8% by mass to 5.0% by mass with respect to the total mass of the ink. The presence of 0.8% by mass or more improves cross-linking efficiency, and beading and color bleeding are more preferable due to a rapid increase in ink viscosity after cross-linking. In the case of 5.0% by mass or less, it is difficult to adversely affect the physical properties of the ink and the state in the ink head, which is preferable from the viewpoints of light emission properties and ink storage stability.

  In the active energy ray cross-linking resin of the present invention, the main chain having a certain degree of polymerization is cross-linked through a cross-linking bond between side chains, and thus polymerizes through a general chain reaction. The effect of increasing the molecular weight per photon is significantly larger than that of an active energy ray curable resin. On the other hand, in the conventionally known active energy ray curable resins, the number of crosslinking points cannot be controlled, so the physical properties of the cured film cannot be controlled, and the film tends to be hard and brittle.

  In the resin used in the present invention, the number of crosslinking points can be completely controlled by the length of the hydrophilic main chain and the amount of side chains introduced, and the physical properties of the ink film can be controlled according to the purpose.

  Furthermore, almost all of the conventionally known active energy ray-curable inks other than the colorant are curable, so that the dots after curing are raised and inferior in image quality typified by gloss, are used in the present invention. The resin requires only a small amount, and since there are many dry components, the image quality after drying is improved and the fixing property is also good.

(Photopolymerization initiator, sensitizer)
In the present invention, it is also preferable to add a photopolymerization initiator or a sensitizer. These compounds may be dissolved or dispersed in a solvent, or may be chemically bonded to the photosensitive resin.

  There is no restriction | limiting in particular about the photoinitiator and photosensitizer which are applied, A conventionally well-known thing can be used.

  Although there is no restriction | limiting in particular about the photoinitiator and photosensitizer which are applied, A water-soluble thing is preferable from a viewpoint of mixability and reaction efficiency. In particular, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (HMPK), thioxanthone ammonium salt (QTX), and benzophenone ammonium salt (ABQ) are preferable from the viewpoint of miscibility with an aqueous solvent.

  Furthermore, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (n = 1, HMPK) represented by the following general formula (7) from the viewpoint of compatibility with the resin, The ethylene oxide adduct (n = 2 to 5) is more preferable.

  In the formula, n represents an integer of 1 to 5.

  Other examples include benzophenones such as benzophenone, hydroxybenzophenone, bis-N, N-dimethylaminobenzophenone, bis-N, N-diethylaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone. Thioxanthones such as thioxatone, 2,4-diethylthioxanthone, isopropylthioxanthone, chlorothioxanthone, and isopropoxychlorothioxanthone. Anthraquinones such as ethyl anthraquinone, benzanthraquinone, aminoanthraquinone and chloroanthraquinone. Acetophenones. Benzoin ethers such as benzoin methyl ether. 2,4,6-trihalomethyltriazines, 1-hydroxycyclohexyl phenyl ketone, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di ( m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-phenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-phenylimidazole dimer, 2- (P-methoxyphenyl) -4,5-diphenylimidazole dimer, 2, -di (p-methoxyphenyl) -5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5 -2,4,5-triarylimidazole dimer of diphenylimidazole dimer, benzyldimethyl ketal, 2-benzyl-2-dimethyl Amino-1- (4-morpholinophenyl) butan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, 2-hydroxy-2-methyl-1-phenyl -Propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, phenanthrenequinone, 9,10-phenanthrenequinone, Benzoins such as methylbenzoin and ethylbenzoin, 9-phenylacridine, acridine derivatives such as 1,7-bis (9,9'-acridinyl) heptane, bisacylphosphine oxide, and mixtures thereof are preferably used. May be used alone or in combination.

  In addition to these photopolymerization initiators, accelerators and the like can also be added. Examples of these include ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, ethanolamine, diethanolamine, triethanolamine and the like.

  Even if these photoinitiators are grafted to the side chain with respect to the hydrophilic main chain.

(Active energy rays, irradiation method)
The active energy ray as used in the present invention includes, for example, electron beam, ultraviolet ray, α ray, β ray, γ ray, X ray and the like. However, it is dangerous to human body, easy to handle, and industrially used. Electron beams and ultraviolet rays are widely used.

  When using an electron beam, the amount of the electron beam to be irradiated is preferably in the range of 0.1 to 30 Mrad. If it is less than 0.1 Mrad, a sufficient irradiation effect cannot be obtained, and if it exceeds 30 Mrad, the support or the like may be deteriorated.

  When using ultraviolet rays, the light source is a low pressure, medium pressure, high pressure mercury lamp, metal halide lamp, xenon lamp having a light emission wavelength in the ultraviolet region, cold cathode tube, hot cathode tube, for example, having an operating pressure of 0.1 kPa to 1 MPa. A conventionally well-known thing, such as LED, is used.

(Light irradiation conditions after ink landing)
As the irradiation condition of actinic rays, actinic rays are preferably irradiated between 0.001 and 1.0 seconds after ink landing, and more preferably 0.001 to 0.5 seconds. In order to form a high-definition image, it is particularly important that the irradiation timing is as early as possible.

  As the light irradiation conditions of the present invention, white ink is first ejected onto a recording medium by an ink jet recording apparatus, and after the ink has landed, actinic rays are irradiated for 0.001 to 1.0 seconds. After curing, the color ink is ejected from above the white ink layer on the recording medium, and after the ink has landed, it is cured by irradiation with active energy rays for 0.001 to 1.0 seconds. The method is preferred.

(Installation of lamp)
As a method for irradiating actinic rays, the basic method is disclosed in JP-A-60-132767. According to this, the light source is provided on both sides of the head unit, and the head and the light source are scanned by the shuttle method. Irradiation is performed after a certain period of time after ink landing. Further, the curing is completed by another light source that is not driven. In US Pat. No. 6,145,979, as an irradiation method, a method using an optical fiber or a method of applying a collimated light source to a mirror surface provided on the side of the head unit and irradiating the recording unit with UV light is disclosed. Yes. Any of these irradiation methods can be used in the image forming method of the present invention.

[Colorant]
As the color material used in the ink jet ink of the present invention, it is preferable to use a dye or a pigment.

(dye)
There is no restriction | limiting in particular as dye which can be used by this invention, Water-soluble dyes, such as an acid dye, a direct dye, and a reactive dye, a disperse dye, etc. are mentioned.

  Specific examples of dyes applicable to the ink jet ink of the present invention are listed below, but the present invention is not limited to these exemplified dyes.

[Water-soluble dye]
Examples of water-soluble dyes that can be used in the present invention include azo dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, phthalocyanine dyes, triphenylmethane dyes, and diphenylmethane dyes.

<C. I. Acid Yellow>
1, 3, 11, 17, 18, 19, 23, 25, 36, 38, 40, 42, 44, 49, 59, 61, 65, 67, 72, 73, 79, 99, 104, 110, 114, 116, 118, 121, 127, 129, 135, 137, 141, 143, 151, 155, 158, 159, 169, 176, 184, 193, 200, 204, 207, 215, 219, 220, 230, 232, 235, 241, 242, 246,
<C. I. Acid Orange>
3, 7, 8, 10, 19, 24, 51, 56, 67, 74, 80, 86, 87, 88, 89, 94, 95, 107, 108, 116, 122, 127, 140, 142, 144, 149, 152, 156, 162, 166, 168,
<C. I. Acid Red>
88, 97, 106, 111, 114, 118, 119, 127, 131, 138, 143, 145, 151, 183, 195, 198, 211, 215, 217, 225, 226, 249, 251, 254, 256, 257, 260, 261, 265, 266, 274, 276, 277, 289, 296, 299, 315, 318, 336, 337, 357, 359, 361, 362, 364, 366, 399, 407, 415,
<C. I. Acid Violet>
17, 19, 21, 42, 43, 47, 48, 49, 54, 66, 78, 90, 97, 102, 109, 126,
<C. I. Acid Blue>
1, 7, 9, 15, 23, 25, 40, 62, 72, 74, 80, 83, 90, 92, 103, 104, 112, 113, 114, 120, 127, 128, 129, 138, 140, 142, 156, 158, 171, 182, 185, 193, 199, 201, 203, 204, 205, 207, 209, 220, 221, 224, 225, 229, 230, 239, 249, 258, 260, 264, 278, 279, 280, 284, 290, 296, 298, 300, 317, 324, 333, 335, 338, 342, 350,
<C. I. Acid Green>
9, 12, 16, 19, 20, 25, 27, 28, 40, 43, 56, 73, 81, 84, 104, 108, 109,
<C. I. Acid Brown>
2, 4, 13, 14, 19, 28, 44, 123, 224, 226, 227, 248, 282, 283, 289, 294, 297, 298, 301, 355, 357, 413, <C. I. Acid Black>
1, 2, 3, 24, 26, 31, 50, 52, 58, 60, 63, 107, 109, 112, 119, 132, 140, 155, 172, 187, 188, 194, 207, 222,
<C. I. Direct yellow>
8, 9, 10, 11, 12, 22, 27, 28, 39, 44, 50, 58, 79, 86, 87, 98, 105, 106, 130, 132, 137, 142, 147, 153,
<C. I. Direct orange>
6, 26, 27, 34, 39, 40, 46, 102, 105, 107, 118,
<C. I. Direct Red>
2, 4, 9, 23, 24, 31, 54, 62, 69, 79, 80, 81, 83, 84, 89, 95, 212, 224, 225, 226, 227, 239, 242, 243, 254,
<C. I. Direct Violet>
9, 35, 51, 66, 94, 95,
<C. I. Direct Blue>
1, 15, 71, 76, 77, 78, 80, 86, 87, 90, 98, 106, 108, 160, 168, 189, 192, 193, 199, 200, 201, 202, 203, 218, 225, 229, 237, 244, 248, 251, 270, 273, 274, 290, 291,
<C. I. Direct Green>
26, 28, 59, 80, 85,
<C. I. Direct Brown>
44, 106, 115, 195, 209, 210, 222, 223,
<C. I. Direct Black>
17, 19, 22, 32, 51, 62, 108, 112, 113, 117, 118, 132, 146, 154, 159, 169,
<C. I. Basic Yellow>
1, 2, 11, 13, 15, 19, 21, 28, 29, 32, 36, 40, 41, 45, 51, 63, 67, 70, 73, 91,
<C. I. Basic Orange>
2, 21, 22,
<C. I. Basic Red>
1, 2, 12, 13, 14, 15, 18, 23, 24, 27, 29, 35, 36, 39, 46, 51, 52, 69, 70, 73, 82, 109,
<C. I. Basic Violet>
1, 3, 7, 10, 11, 15, 16, 21, 27, 39,
<C. I. Basic Blue>
1, 3, 7, 9, 21, 22, 26, 41, 45, 47, 52, 54, 65, 69, 75, 77, 92, 100, 105, 117, 124, 129, 147, 151,
<C. I. Basic Green>
1, 4,
<C. I. Basic Brown>
1,
<C. I. Reactive Yellow>
2, 3, 7, 15, 17, 18, 22, 23, 24, 25, 27, 37, 39, 42, 57, 69, 76, 81, 84, 85, 86, 87, 92, 95, 102, 105, 111, 125, 135, 136, 137, 142, 143, 145, 151, 160, 161, 165, 167, 168, 175, 176,
<C. I. Reactive Orange>
1, 4, 5, 7, 11, 12, 13, 15, 16, 20, 30, 35, 56, 64, 67, 69, 70, 72, 74, 82, 84, 86, 87, 91, 92, 93, 95, 107,
<C. I. Reactive Red>
2, 3, 5, 8, 11, 21, 22, 23, 24, 28, 29, 31, 33, 35, 43, 45, 49, 55, 56, 58, 65, 66, 78, 83, 84, 106, 111, 112, 113, 114, 116, 120, 123, 124, 128, 130, 136, 141, 147, 158, 159, 171, 174, 180, 183, 184, 187, 190, 193, 194, 195, 198, 218, 220, 222, 223, 228, 235,
<C. I. Reactive Violet>
1, 2, 4, 5, 6, 22, 23, 33, 36, 38,
<C. I. Reactive Blue>
2, 3, 4, 5, 7, 13, 14, 15, 19, 21, 25, 27, 28, 29, 38, 39, 41, 49, 50, 52, 63, 69, 71, 72, 77, 79, 89, 104, 109, 112, 113, 114, 116, 119, 120, 122, 137, 140, 143, 147, 160, 161, 162, 163, 168, 171, 176, 182, 184, 191, 194, 195, 198, 203, 204, 207, 209, 211, 214, 220, 221, 222, 231, 235, 236,
<C. I. Reactive Green>
8, 12, 15, 19, 21,
<C. I. Reactive Brown>
2, 7, 9, 10, 11, 17, 18, 19, 21, 23, 31, 37, 43, 46,
<C. I. Reactive Black>
5, 8, 13, 14, 31, 34, 39,
<C. I. Food Black>
1, 2,
Etc.

  Furthermore, examples of the dye include a compound represented by the following general formula (8) or a compound represented by the general formula (9).

In the general formula (8), R ₁ represents a hydrogen atom or a substitutable substituent, and is preferably a hydrogen atom or a phenylcarbonyl group. R ₂ may be different and represents a hydrogen atom or a substitutable substituent, and is preferably a hydrogen atom. R ₃ represents a hydrogen atom or a substitutable substituent, and is preferably a hydrogen atom or an alkyl group. R ₄ represents a hydrogen atom or a substitutable substituent, preferably a hydrogen atom or an aryloxy group. R ₅ may be different and represents a hydrogen atom or a substitutable substituent, and is preferably a sulfonic acid group. n represents an integer of 1 to 4, and m represents an integer of 1 to 5.

  In the general formula (9), X represents a phenyl group or a naphthyl group, may be substituted with a substitutable substituent, and is preferably substituted with a sulfonic acid group or a carboxyl group. Y represents hydrogen ion, sodium ion, potassium ion, lithium ion, ammonium ion or alkylammonium ion. Re may be different and represents a hydrogen atom or a substituent that can be substituted on the naphthalene ring. q represents 1 or 2. p represents an integer of 1 to 4. However, q + p = 5. Z represents a substitutable substituent, and represents a carbonyl group, a sulfonyl group or a group represented by the following general formula (10), and particularly preferably a group represented by the following general formula (10).

In the general formula (10), W ₁ and W ₂ each independently represent a halogen atom, amino group, hydroxyl group, alkylamino group or arylamino group, preferably a halogen atom, hydroxyl group or alkylamino group.

[Disperse dye]
As the disperse dye, various disperse dyes such as azo disperse dyes, quinone disperse dyes, anthraquinone disperse dyes, quinophthalone disperse dyes can be used, and specific compounds thereof are listed below.

<C. I. Disperse Yellow>
3, 4, 5, 7, 9, 13, 23, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 63, 64, 66, 68, 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 108, 114, 116, 118, 119, 122, 124, 126, 135, 140, 141, 149, 160, 162, 163, 164, 165, 179, 180, 182, 183, 184, 186, 192, 198, 199, 202, 204, 210, 211, 215, 216, 218, 224, 227, 231, 232,
<C. I. Disperse Orange>
1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 47, 48, 49, 50, 53, 54, 55, 56, 57, 58, 59, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130, 139, 142,
<C. I. Disperse Red>
1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122, 126, 127, 128, 131, 132, 134, 135, 137, 143, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 227, 229, 23 , 240,257,258,277,278,279,281,288,298,302,303,310,311,312,320,324,328,
<C. I. Disperse Violet>
1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63, 69, 77,
<C. I. Disperse Green>
9,
<C. I. Disperse Brown>
1, 2, 4, 9, 13, 19,
<C. I. Disperse Blue>
3, 7, 9, 14, 16, 19, 20, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79, 81, 82, 83, 87, 91, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128, 130, 139, 141, 142, 143, 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201, 205, 207, 211, 214, 224, 225, 257, 259, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 3 0,333,
<C. I. Disperse Black>
1, 3, 10, 24
Etc.

<Pigment>
As the pigment that can be used in the present invention, conventionally known organic and inorganic pigments can be used, but they are anionic pigments. For example, azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc. Examples include cyclic pigments, dye lakes such as acid dye lakes, organic pigments such as nitro pigments, nitroso pigments, aniline black, and daylight fluorescent pigments, and inorganic pigments such as carbon black.

  Specific organic pigments are exemplified below.

  Examples of pigments for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the orange or yellow pigment include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. And CI Pigment Yellow 138.

  Examples of pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

[Pig for white ink]
As the colorant used in the white ink according to the present invention, inorganic and / or organic white pigments can be used. Examples of inorganic white pigments include alkaline earth metal sulfates such as barium sulfate, alkaline earth metal carbonates such as calcium carbonate, silicas such as finely divided silicic acid and synthetic silicates, calcium silicate, alumina, Alumina hydrate, titanium oxide, zinc oxide, talc, clay and the like can be mentioned. Titanium oxide is preferable in terms of hiding properties and coloring power.

  Examples of the organic white pigment include organic compound salts disclosed in JP-A No. 11-129613 and alkylene bismelamine derivatives disclosed in JP-A Nos. 11-14365 and 2001-234093. Specific examples of the white pigment include Shigenox OWP, Shigenox OWPL, Shigenox FWP, Shigenox FWG, Shigenox UL, and Shigenox U (all trade names manufactured by Hackol Chemical Co., Ltd.).

[Titanium oxide]
Titanium oxide has three crystal forms of anatase type, rutile type, and brookite type, and general-purpose ones can be broadly classified into anatase type and rutile type. The anatase type has a small specific gravity and tends to have a small particle size, while the rutile type has a large refractive index and high concealment. In the present invention, any of them may be used, but it is preferable to make a selection according to the application by making use of each feature. By using an anatase type which has a small specific gravity and is easy to reduce the particle size, dispersion stability, ink storage stability, and emission properties are improved. In addition, two or more different crystal forms may be used, and the addition amount of titanium oxide can be reduced by using anatase type and rutile type having high coloring power in combination, so that the storage stability and emission properties of ink are improved. .

  As the surface treatment method of titanium oxide, aqueous treatment, vapor phase treatment, etc. are performed, but as the surface treatment agent, alumina / silica treatment is generally used, and untreated, alumina treatment, and alumina / silica treatment are available. is there.

  As a method for dispersing the pigment, for example, various dispersing machines such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used. It is also preferable to use a centrifugal separator or a filter for the purpose of removing the coarse particles of the pigment dispersion.

  In the ink according to the present invention, a self-dispersed pigment in which polar groups such as sulfonic acid and carboxylic acid are pendant on the pigment surface, or a pigment dispersed using a polymer dispersant is preferable.

  In the present invention, the polymer dispersant is not particularly limited, and a water-soluble resin or a water-insoluble resin is used. Examples of these polymers include styrene, styrene derivatives, vinyl naphthalene derivatives, acrylic acid, acrylic acid derivatives, methacrylic acid, methacrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, fumaric acid. Examples thereof include a polymer composed of a single monomer selected from acid derivatives, a copolymer composed of two or more monomers, and salts thereof. Water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, cellulose derivatives, gelatin, and polyethylene glycol can also be used.

  The content of these water-soluble resins with respect to the total amount of ink is preferably 0.1 to 10% by mass, and more preferably 0.3 to 5% by mass. These water-soluble resins can be used in combination of two or more.

  The average particle size of the pigment dispersion used in the inkjet ink of the present invention is preferably 500 nm or less, more preferably 200 nm or less, preferably 10 nm or more and 200 nm or less, and more preferably 10 nm or more and 150 nm or less. If the average particle size of the pigment dispersion exceeds 500 nm, the dispersion becomes unstable. In addition, even when the average particle size of the pigment dispersion is less than 10 nm, the stability of the pigment dispersion tends to deteriorate, and the storage stability of the ink tends to deteriorate.

  The particle size of the pigment dispersion can be determined by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, a laser Doppler method or the like. It is also possible to obtain a particle image with a transmission electron microscope on at least 100 particles and perform statistical processing on the image using image analysis software such as Image-Pro (manufactured by Media Cybernetics). Is possible.

  Various methods such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used as a pigment dispersion method.

<Water-soluble solvent>
In the present invention, an aqueous liquid medium is preferably used as the solvent, and a mixed solvent such as water and a water-soluble organic solvent is more preferably used as the aqueous liquid medium. Examples of water-soluble organic solvents that are preferably used include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, Triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), polyhydric alcohol ethers (eg, ethylene glycol monomethyl ether, ethylene Glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Nomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, ethylene glycol Monophenyl ether, propylene glycol monophenyl ether), amines (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetra) , Tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2 -Pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone), sulfoxides (for example, dimethyl sulfoxide) and the like.

<Surfactant>
Surfactants preferably used in the ink of the present invention include alkyl sulfates, alkyl ester sulfates, dialkyl sulfosuccinates, alkyl naphthalene sulfonates, alkyl phosphates, polyoxyalkylene alkyl ether phosphates, fatty acids. Anionic surfactants such as salts, nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyalkylene alkyl phenyl ethers, acetylene glycols, polyoxyethylene-polyoxypropylene block copolymers, glycerin esters, sorbitan Activators such as esters, polyoxyethylene fatty acid amides and amine oxides, and cationic surfactants such as alkylamine salts and quaternary ammonium salts.

  These surfactants can also be used as pigment dispersants, and in particular, anionic and nonionic surfactants can be preferably used.

<Various additives>
In the present invention, other conventionally known additives can be contained. For example, optical brighteners, antifoaming agents, lubricants, preservatives, thickeners, antistatic agents, matting agents, water-soluble polyvalent metal salts, acid bases, pH adjusters such as buffer solutions, antioxidants, surface tension It is a regulator, a non-resistance modifier, a rust inhibitor, an inorganic pigment, and the like.

<Recording sheet>
The paper, coated paper, there is a non-coated paper, as the coated paper, the coating amount per 1m ² is one side 20g before and after of art paper, 1m ² per coated amount on one side 10g before and after the coated paper Examples include a light-weight coated paper having a coating amount per 1 m ^{2 of} about 5 g on one side, a finely coated paper, a mat-like finished mat-coated paper, a dull-like finished dull-coated paper, and a newsprint. Non-coated paper includes printing paper A using 100% chemical pulp, printing paper B using 70% or more chemical pulp, printing paper C using 40% or more and less than 70% chemical pulp, and printing using less than 40% chemical pulp. Examples thereof include paper D, gravure paper containing mechanical pulp and subjected to calendar treatment. Further details are described in detail in the “Latest Paper Processing Handbook” edited by the Paper Processing Handbook Editorial Committee, published by Tech Times, “Printing Engineering Handbook” edited by the Japan Printing Society.

  The plain paper is 80 to 200 μm uncoated paper belonging to a part of uncoated paper, special printing paper and information paper. The plain paper used in the present invention includes, for example, high-grade printing paper, intermediate-grade printing paper, low-grade printing paper, thin-like printing paper, fine-coating printing paper, special printing paper such as fine-quality printing paper, foam paper, PPC paper, and others There are information sheets and the like. Specifically, there are the following sheets and various modified / processed sheets using these sheets, but the present invention is not particularly limited thereto. High quality paper and colored high quality paper, recycled paper, copy paper / colored paper, OCR paper, carbonless paper / colored paper, synthetic paper such as YUPO 60, 80, 110 microns, YUPO COAT 70, 90 microns, etc. Coated paper 90kg, Foam mat paper 70, 90, 110kg, Foamed PET 38 microns, Mitsuori-kun (above, Kobayashi recording paper), OK fine paper, New OK fine paper, Sunflower, Phoenix, OK Royal White, Export fine paper ( NPP, NCP, NWP, Royal White) OK Book Paper, OK Cream Book Paper, Cream Premium Paper, OK Map Paper, OK Ishikari, Cucumber, OK Foam, OKH, NIP-N (above, Shin Oji Paper), Gold Wang, Toko, export quality paper, special demand quality paper, book paper, book paper L, light cream book paper, elementary textbook Paper, continuous slip paper, high quality NIP paper, silver ring, gold yang, gold yang (W), bridge, capital, silver ring book, harp, harp cream, SK color, securities paper, opera cream, opera, KYP medical record, silvia HN, Excellent Foam, NPI Foam DX (Nippon Paper), Pearl, Kinryo, Uscream fine paper, Special Book Paper, Super Book Paper, Book Paper, Diamond Foam, Inkjet Foam (Mitsubishi Paper), Carpet V, carpet SW, white elephant, luxury publication paper, cream carpet, cream white elephant, securities / voucher paper, book paper, map paper, copy paper, HNF (above, Hokuetsu), phone book cover, Book paper, cream shirairai, cream shirairaifu, cream shirairaifu, DSK (above, Daishowa Paper), Sendai MP fine paper, Jiang, Thunderbird quality, hanging paper, colored paper base, dictionary paper, cream book, white book, cream quality paper, map paper, continuous slip paper (above, Chuetsu Pulp), OP gold cherry (Chuetsu), gold sand, reference book paper, Replacement certificate paper (white), form printing paper, KRF, white foam, color foam, (K) NIP, fine PPC, Kishu inkjet paper (above, made by Kishu Paper), Taiou, Bright Foam, Kant, Kant White, Dante , CM paper, Dante comic, Heine, paperback book paper, Heine S, New AD paper, Utrilo Excel, Excel Super A, Kant Excel, Excel Super B, Dante Excel, Heine Excel, Excel Super C, Excel Super D, AD Excel, Excel Super E, New Bright Foam, New Bright NI P (above, made by Daio Paper), Sun Ring, Moon Ring, Cloud Pass, Galaxy, Baiyun, Wyeth, Moon Ring Ace, Baiyun Ace, Cloud Pass Ace (above, Nippon Paper Industries), Taiou, Bright Foam, Bright Nip (Nagoya Pulp), Peony A, Golden Pigeon, Special Peony, White Peony A, White Peony C, Silver Pigeon, Super White Peony A, Light Cream White Peony, Special Medium Quality Paper, White Pigeon, Super Medium Quality Paper, Blue Pigeon, Red Pigeon, Gold Pigeon M Snow Vision, Snow Vision, Gold Pigeon Snow Vision, White Pigeon M, Super DX, Hamanasu O, Red Pigeon M, HK Super Printing Paper (Made by Honshu Paper), Stalinden (A・ AW), Star Elm, Star Maple, Star Laurel, Star Poplar, MOP, Star Cherry I, Cherry I Super, Cherry II Super, Star Cherry III, Star Cherry IV, Cherry III Super, Cheri -IV Super (above, made by Maruzumi Paper), SHF (above, made by Toyo Pulp), TRP (above, made by Tokai Pulp), etc.

<Various films>
As the various films, all commonly used films can be used. For example, there are a polyester film, a polyolefin film, a polyvinyl chloride film, a polyvinylidene chloride film, and the like. Resin-coated paper that is photographic printing paper or YUPO paper that is synthetic paper can also be used.

<Various inkjet recording media>
As the various ink jet recording media, an ink receiving layer is formed on the surface using an absorbent support or a non-absorbent support as a base material. Examples of the ink receiving layer include a coating layer, a swelling layer, and a fine void layer.

  The swelling layer absorbs ink when the ink receiving layer made of a water-soluble polymer swells. The fine void layer is composed of inorganic or organic fine particles having a secondary particle size of about 20 to 200 nm and a binder, and fine voids of about 100 nm absorb ink.

  In recent years, an inkjet recording medium in which the above-mentioned fine void layer is provided on a base material using RC paper in which both sides of a paper base material are coated with an olefin resin is preferably used in terms of photographic images.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. In the examples, “%” represents mass% unless otherwise specified. Further, unless otherwise specified, “part” in the examples represents “part by mass”.

Example 1
<Synthesis of Polymer Compound 1>
56 g of glycidyl methacrylate, 48 g of p-hydroxybenzaldehyde, 2 g of pyridine, and 1 g of N-nitroso-phenylhydroxyamine ammonium salt were each put in a reaction vessel and stirred in a hot water bath at 80 ° C. for 8 hours.

  Next, 45 g of a polyvinyl acetate saponified product having a polymerization degree of 300 and a saponification degree of 88% was dispersed in 225 g of ion-exchanged water, and then 4.5 g of phosphoric acid was added to this solution and p- (3- (Methacryloxy-2-hydroxypropyloxy) benzaldehyde was added under the condition that the modification rate was 3 mol% with respect to the saponified polyvinyl acetate, and the mixture was stirred at 90 ° C. for 6 hours. After cooling the resulting solution to room temperature, 30 g of basic ion exchange resin was added and stirred for 1 hour. Next, the ion exchange resin was filtered, and Irgacure 2959 (manufactured by Ciba Specialty Chemicals) was mixed here as a photopolymerization initiator at a ratio of 0.1 g with respect to 100 g of a 15% aqueous solution. Dilution gave a 12% aqueous solution of polymer compound 1.

<Synthesis of polymer compound 2>
A 12% aqueous solution of polymer compound 2 was obtained in the same manner as polymer compound 1 except that the crosslinking group modification rate of the polyvinyl acetate saponified product was changed to 0.4 mol% in the synthesis of polymer compound 1.

<Synthesis of Polymer Compound 3>
A 12% aqueous solution of polymer compound 2 was obtained in the same manner as polymer compound 1 except that the crosslinking group modification rate of the polyvinyl acetate saponified product was changed to 4.5 mol% in the synthesis of polymer compound 1.

<Synthesis of Polymer Compound 4>
A 12% aqueous solution of polymer compound 4 was obtained in the same manner as polymer compound 1 except that the polymerization degree of polyvinyl acetate saponified product was changed to 180 in the synthesis of polymer compound 1.

<Synthesis of Polymer Compound 5>
A 5% aqueous solution of polymer compound 5 was obtained in the same manner as polymer compound 1 except that the polymerization degree of polyvinyl acetate saponified product was changed to 4500 in the synthesis of polymer compound 1.

<Preparation of ink>
(Preparation of pigment dispersion)
(Yellow pigment dispersion)
The following additives were mixed and dispersed using a sand grinder filled with 0.5 mm zirconia beads at a volume ratio of 50% to prepare a yellow pigment dispersion having a yellow pigment content of 10%.

C. I. Pigment Yellow 74 95g
Demall C (Kao Corporation) 65g
Ethylene glycol 100g
Ion exchange water 120g
(Preparation of magenta pigment dispersion)
The following additives were mixed and dispersed using a sand grinder filled with 50% by volume of 0.5 mm zirconia beads to prepare a magenta pigment dispersion having a magenta pigment content of 10%. The average particle size of the magenta pigment particles contained in this magenta pigment dispersion was 83 nm. The particle size was measured using a Zetasizer 1000HS manufactured by Malvern.

C. I. Pigment Red 122 10 parts Jonkrill 61 (acrylic styrene resin dispersant, manufactured by Johnson) 3 parts Glycerin 15 parts Ion-exchanged water 72 parts (Cyan pigment dispersion)
The following additives were mixed and dispersed using a sand grinder filled with 50% by volume of 0.5 mm zirconia beads to prepare a cyan pigment dispersion having a cyan pigment content of 10%.

C. I. Pigment Blue 15: 3 100g
DEMAL C 68g
Diethylene glycol 100g
125g of ion exchange water
(White pigment dispersion)
The following additives were mixed and dispersed using a sand grinder filled with 0.5 mm zirconia beads at a volume ratio of 50% to prepare a white pigment dispersion having a white pigment content of 20%.

C. I. Pigment White 6 (Anatase-type titanium oxide, average particle size 0.16 μm)
120g
Jonkrill 62 (acrylic styrene resin dispersant, manufactured by Johnson Polymer Co., Ltd.) 59 g
Lebenol WX (Kao Corporation) 3g
Diethylene glycol 100g
Ion exchange water 300g
Hereinafter, pigment type ink sets (three colors of Y, M, and C) 1 to 7 were prepared.

<Preparation of ink set 1>
Ink set 1 composed of yellow ink Y1, magenta ink M1, and cyan ink C1 was produced as follows.

(Preparation of yellow ink Y1)
Yellow pigment dispersion 30 parts 12% aqueous solution of polymer compound 1 17 parts Glycerol 7 parts Ethylene glycol 15 parts Diethylene glycol monobutyl ether 2 parts Orphine e1010 (manufactured by Nissin Chemical Co., Ltd.) 0.2 parts Was 100 parts, and yellow ink Y1 was produced.
(Preparation of magenta ink M1)
Magenta ink M1 was produced in the same manner as yellow ink Y1, except that the yellow pigment dispersion was changed to a magenta pigment dispersion in the production of yellow ink Y1.

(Preparation of cyan ink C1)
A cyan ink C1 was produced in the same manner as the yellow ink Y1, except that the yellow pigment dispersion was changed to a cyan pigment dispersion in the production of the yellow ink Y1.

<Preparation of ink set 2>
Ink set 2 composed of yellow ink Y2, magenta ink M2, and cyan ink C2 was produced as follows.

(Preparation of yellow ink Y2)
A yellow ink Y2 was prepared in the same manner as in the preparation of the yellow ink Y1, except that a 12% aqueous solution of the polymer compound 2 was used instead of the 12% aqueous solution of the polymer compound 1.

(Preparation of magenta ink M2)
Magenta ink M2 was produced in the same manner as yellow ink Y2, except that the yellow pigment dispersion was changed to a magenta pigment dispersion in the production of yellow ink Y2.

(Preparation of cyan ink C2)
Cyan ink C2 was produced in the same manner as yellow ink Y2, except that the yellow pigment dispersion was changed to a cyan pigment dispersion in the production of yellow ink Y2.

<Preparation of ink set 3>
Ink set 3 composed of yellow ink Y3, magenta ink M3 and cyan ink C3 was produced as follows.

(Preparation of yellow ink Y3)
A yellow ink Y3 was prepared in the same manner as in the preparation of the yellow ink Y1, except that a 12% aqueous solution of the polymer compound 3 was used instead of the 12% aqueous solution of the polymer compound 1.

(Preparation of magenta ink M3)
A magenta ink M3 was produced in the same manner as the yellow ink Y3 except that the yellow pigment dispersion was changed to a magenta pigment dispersion in the production of the yellow ink Y3.

(Preparation of cyan ink C3)
A cyan ink C3 was produced in the same manner as the yellow ink Y3 except that the yellow pigment dispersion was changed to a cyan pigment dispersion in the production of the yellow ink Y3.

<Preparation of ink set 4>
Ink set 4 composed of yellow ink Y4, magenta ink M4 and cyan ink C4 was produced as follows.

(Preparation of yellow ink Y4)
A yellow ink Y4 was prepared in the same manner as in the preparation of the yellow ink Y1, except that a 12% aqueous solution of the polymer compound 4 was used instead of the 12% aqueous solution of the polymer compound 1.

(Preparation of magenta ink M4)
A magenta ink M4 was produced in the same manner as the yellow ink Y4 except that the yellow pigment dispersion was changed to a magenta pigment dispersion in the production of the yellow ink Y4.

(Preparation of cyan ink C4)
A cyan ink C4 was produced in the same manner as the yellow ink Y4 except that the yellow pigment dispersion was changed to a cyan pigment dispersion in the production of the yellow ink Y4.

<Preparation of ink set 5>
Ink set 5 composed of yellow ink Y5, magenta ink M5 and cyan ink C5 was produced as follows.
(Preparation of yellow ink Y5)
Yellow pigment dispersion 30 parts 5% aqueous solution of polymer compound 5 40 parts Glycerol 7 parts Ethylene glycol 15 parts Diethylene glycol monobutyl ether 2 parts Orphine e1010 (manufactured by Nissin Chemical Co., Ltd.) 0.2 parts Was 100 parts, and yellow ink Y5 was produced.

(Preparation of magenta ink M5)
A magenta ink M5 was produced in the same manner as the yellow ink Y5 except that the yellow pigment dispersion was changed to a magenta pigment dispersion in the production of the yellow ink Y5.

(Preparation of cyan ink C5)
A cyan ink C5 was produced in the same manner as the yellow ink Y5 except that the yellow pigment dispersion was changed to a cyan pigment dispersion in the production of the yellow ink Y5.

<Preparation of ink set 6>
Ink set 6 composed of yellow ink Y6, magenta ink M6 and cyan ink C6 was produced as follows.

(Preparation of yellow ink Y6)
Yellow pigment dispersion 30 parts 12% aqueous solution of polymer compound 1 4.2 parts Glycerol 7 parts Ethylene glycol 15 parts Diethylene glycol monobutyl ether 2 parts Orphine e1010 (manufactured by Nissin Chemical) 0.2 parts In addition, the total amount was 100 parts, and yellow ink Y6 was produced.

(Preparation of magenta ink M6)
A magenta ink M6 was produced in the same manner as the yellow ink Y6 except that the yellow pigment dispersion was changed to a magenta pigment dispersion in the production of the yellow ink Y6.

(Preparation of cyan ink C6)
Cyan ink C6 was produced in the same manner as yellow ink Y6 except that the yellow pigment dispersion was changed to a cyan pigment dispersion in the production of yellow ink Y6.

<Preparation of ink set 7>
Ink set 7 composed of yellow ink Y7, magenta ink M7 and cyan ink C7 was produced as follows.

(Preparation of yellow ink Y7)
Yellow pigment dispersion 30 parts 12% aqueous solution of polymer compound 1 43 parts Glycerol 7 parts Ethylene glycol 15 parts Diethylene glycol monobutyl ether 2 parts Olfine e1010 (manufactured by Nissin Chemical Co., Ltd.) 0.2 parts Was 100 parts, and yellow ink Y7 was produced.

(Preparation of magenta ink M7)
A magenta ink M7 was produced in the same manner as the yellow ink Y7 except that the yellow pigment dispersion was changed to a magenta pigment dispersion in the production of the yellow ink Y7.

(Preparation of cyan ink C7)
A cyan ink C7 was produced in the same manner as the yellow ink Y7 except that the yellow pigment dispersion was changed to a cyan pigment dispersion in the production of the yellow ink Y7.

<Preparation of white inks W1 to W6>
White pigment dispersion 30 parts 12% aqueous solution of polymer compound 1 17 parts Glycerol 7 parts Ethylene glycol 15 parts Diethylene glycol monobutyl ether 2 parts Ion-exchanged water 20 parts Surfactant Olfine e1010 (manufactured by Nisshin Chemical Co., Ltd.) ) Was appropriately added between 0.05 and 0.5 part, and the remainder was added with ion-exchanged water and stirred to prepare six types of white inks (W1 to W6) having different surface tensions.

  Table 1 shows the combinations of the Y, M, and C three-color ink sets 1 to 7 and the white inks W1 to W6 and the difference in surface tension between the white ink and the color ink. The following evaluation was performed on these ink combinations.

(Evaluation of beading resistance)
An on-demand type with a maximum recording density of 720 × 720 dpi using a piezo head having a nozzle diameter of 25 μm, a drive frequency of 12 kHz, a nozzle count of 128, and a nozzle density of 180 dpi (dpi represents the number of dots per 2.54 cm). Using an inkjet printer, 5 cm × 5 cm magenta solid was printed on art paper (Oji Paper's OK Kanto +) and visually observed, and beading resistance was evaluated according to the following criteria.

  In addition, each ink was continuously ejected, and 0.1 seconds after landing, 120 W / cm metal halide lamps (MAL 400NL manufactured by Nihon Battery Co., Ltd., power supply power 3 kW · hr) disposed at both ends of the piezoelectric head were irradiated.

◎: Uniform image ○: Mottled noise that can be seen when viewed closely is present in less than 5 points Δ: Mottled noise that can be understood when viewed carefully is present in less than 10 points ×: Clear mottled noise is 10 Existence of more than one place XX: There are more than 20 mottled noises. Among these, XX and XX are levels at which there is a problem as a product.

(Evaluation of bleed resistance)
Using an on-demand type ink jet printer with a maximum recording density of 720 × 720 dpi, using a piezo-type head with a nozzle diameter of 25 μm, a drive frequency of 12 kHz, a nozzle number of 128, and a nozzle density of 180 dpi, art paper (OK Koji Fuji manufactured by Oji Paper) A black thin line having a width of 200 μm was printed on the magenta solid and then visually observed, and bleed resistance was evaluated according to the following criteria.

  In addition, each ink was continuously ejected, and 0.1 seconds after landing, 120 W / cm metal halide lamps (MAL 400NL manufactured by Nihon Battery Co., Ltd., power supply power 3 kW · hr) disposed at both ends of the piezoelectric head were irradiated.

◎: The boundary between the fine line and the solid is clear. ○: The boundary is slightly blurred, but the quality has no problem in practical use. △: The boundary is blurred but is practically acceptable. X: Obvious blurring is observed at the boundary, the line width is about 1.5 times, and this is a quality that is a practical problem. XX: The boundary between the fine line and the solid part is unclear. Quality and bleed resistance is extremely poor.

(Evaluation of solid lines)
After the white ink is printed and cured on a recording medium (polyethylene terephthalate film) by the ink jet recording apparatus, an image of the color ink is output onto the white ink and cured by irradiating with active energy rays. The solid part was visually observed and the solid part streak was evaluated according to the following criteria.

◎: Good without streaks ○: There are some streaks, but there is no problem with high-definition printing △: There are streaks, but somehow usable level ×: Level where streaks are noticeable and unusable (Evaluation of solid banding)
After the white ink is printed and cured on a recording medium (polyethylene terephthalate film) by the ink jet recording apparatus, an image of the color ink is output onto the white ink and cured by irradiating with active energy rays. The solid part was visually observed and the solid part banding was evaluated according to the following criteria.

◎: Good without banding ○: Slight banding but no problem with high-definition printing △: Banding is present but somehow usable level ×: Banding is conspicuous and unusable level Each evaluation result is shown in Table 2 .

  From Table 2, it is clear that the ink composition set of the present invention is excellent in all evaluations of beading resistance, bleeding resistance, solid streaks, and solid banding.

  As described above, according to the present invention, there are a variety of recording media, feathering and bleeding can be prevented, and solid lines and banding can be applied to non-ink-absorbing films and recording media with low brightness. Ink jet ink sets capable of obtaining a high-definition image free of ink and an ink jet recording method using the same can be provided.

Claims (10)

A color ink containing at least a colorant, water, a polymer compound having a plurality of side chains in a hydrophilic main chain and capable of crosslinking between side chains by irradiation with active energy rays; An ink-jet ink set comprising an ink, wherein the white ink has a surface tension higher than that of the color ink. After the white ink according to claim 1 is first jetted onto the recording medium by an ink jet recording apparatus and cured by irradiation with active energy rays, the color ink according to claim 1 is applied to the white ink on the recording medium. An ink jet recording method, comprising: jetting from above an ink layer, irradiating and curing an active energy ray to form an image. The inkjet ink set according to claim 1 or 2, wherein the white ink has a surface tension of 0.5 to 5 mN / m higher than that of the color ink having the highest surface tension. The ink set for inkjet according to any one of claims 1 to 3, wherein the white ink contains titanium oxide as a colorant. 5. The ink set for inkjet according to claim 1, wherein the color ink and the white ink have a surface tension of 20 to 60 mN / m. The ink set for inkjet according to any one of claims 1 to 5, wherein the polymer compound is contained in an amount of 0.8 to 5.0% by mass based on the total mass of the ink. The hydrophilic main chain is a saponified product of polyvinyl acetate, has a saponification degree of 77 to 99%, and a polymerization degree of 200 to 4000. Inkjet ink set. The inkjet ink set according to any one of claims 1 to 7, wherein a modification rate of the side chain with respect to the hydrophilic main chain is 0.8 mol% or more and 4 mol% or less. An image forming method for performing printing on a recording medium by ejecting ink onto the recording medium from the ink jet recording head using the ink set for ink jet according to any one of claims 1 to 8, comprising: After the ink has landed, an actinic ray is irradiated for 0.001 to 1.0 seconds. An ink jet recording method comprising: discharging an ink jet ink set according to any one of claims 1 to 8 onto a recording medium from an ink jet recording head; irradiating with active energy rays; and drying the ink set.