JP2017160352A - Ink set and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set that comprises an ink allowing the recording of an image having excellent color development, light resistance, and moisture resistance, and also allows the recording of an image having excellent bleeding resistance and the recording of a secondary color image having excellent color development (particularly, the color reproduction range of a dark part).SOLUTION: An ink set has a combination of a first ink and a second ink. The first ink contains a self-dispersible pigment in which an ionic group is chemically bound to the surface of a pigment particle directly or through another atomic group, and the second ink contains a compound represented by general formula (1).SELECTED DRAWING: None

Description

  The present invention relates to an ink set and an ink jet recording method.

  In recent years, inkjet recording methods are required to be able to record images with higher image quality and longer storage than ever. In particular, for images recorded using color inks, it is particularly necessary to improve color developability and light resistance. In order to satisfy such requirements, ink dyes capable of recording images with improved color development and light resistance have been proposed. For example, an magenta ink for ink jet recording using an anthrapyridone colorant or a xanthene colorant having a specific structure and capable of recording an image with improved color developability and light resistance has been proposed (Patent Documents 1 to 3). 3).

  In addition, for black ink capable of recording an image excellent in optical density and fastness, it has been widely studied in recent years to use a self-dispersing pigment as a coloring material. For example, in order to record an image with improved optical density, a water-based ink containing self-dispersing carbon black and a specific salt has been proposed (Patent Document 4). Further, an ink containing a self-dispersing pigment in which a functional group having high reactivity with calcium is bonded based on a calcium index that is an index of reactivity with calcium has been proposed (Patent Document 5). Further, an ink set composed of an ink containing a xanthene dye and an ink containing a self-dispersing pigment has been proposed in order to expand the color gamut reproduction range in the dark part (Patent Document 6).

JP 2005-008868 A JP-A-9-241553 JP 2011-148773 A JP 2000-198955 A Special table 2009-515007 JP2012-193308A

  The present inventors examined the image characteristics of a single color portion and a mixed color portion of an image recorded using the ink proposed in the above prior art document. As a result, it has been found that none of the characteristics has reached the level of performance required in recent years. For example, the color developability and light resistance of images recorded with magenta inks proposed in Patent Documents 1 to 3 do not satisfy the high levels required in recent years. Further, it was found that the color reproduction range of the dark portion of the secondary color image recorded by using these magenta inks in combination with the black ink proposed in Patent Documents 4 and 5 is narrow. Furthermore, it was found that the image recorded using the ink set proposed in Patent Document 6 lacks moisture resistance and bleeding resistance.

  Accordingly, an object of the present invention is to provide an ink set including an ink capable of recording an image having excellent color developability, light resistance, and moisture resistance. It is another object of the present invention to provide an ink set capable of recording an image excellent in bleeding resistance and capable of recording a secondary color image excellent in color developability (particularly in a color reproduction range in a dark portion). Another object of the present invention is to provide an ink jet recording method using the ink set.

  The above object is achieved by the present invention described below. That is, according to the present invention, there is provided an ink set having a combination of a first ink and a second ink, wherein the first ink is chemically bonded to the pigment particle surface directly or through other atomic groups. There is provided an ink set comprising a self-dispersing pigment bonded thereto, wherein the second ink contains a compound represented by the following general formula (1).

（前記一般式（１）中、Ｒ₁、Ｒ₅、Ｒ₆及びＲ₁₀は、それぞれ独立に、アルキル基を表す。Ｒ₃及びＲ₈は、それぞれ独立に、水素原子、アルキル基、アルコキシ基、アリールオキシ基、又はイオン性基を表す。Ｒ₂、Ｒ₄、Ｒ₇及びＲ₉は、それぞれ独立に、水素原子、イオン性基、下記一般式（２）で表される基、又は下記一般式（３）で表される基を表し、Ｒ₂、Ｒ₄、Ｒ₇及びＲ₉は、少なくとも１つが下記一般式（２）で表される基である。ｎは、０乃至６の整数を表す。Ｚは、それぞれ独立に、スルホン酸基又はスルファモイル基を表す。ｎが１乃至６の整数である場合、Ｚは、芳香環に結合している）

(In the general formula (1), R ₁ , R ₅ , R ₆ and R ₁₀ each independently represents an alkyl group. R ₃ and R ₈ each independently represent a hydrogen atom, an alkyl group or an alkoxy group. R ₂ , R ₄ , R ₇ and R ₉ each independently represent a hydrogen atom, an ionic group, a group represented by the following general formula (2), or the following: R ₂ , R ₄ , R ₇ and R ₉ each represents a group represented by the following general formula (2), wherein n is 0 to 6 Z represents each independently a sulfonic acid group or a sulfamoyl group. When n is an integer of 1 to 6, Z is bonded to an aromatic ring)

（前記一般式（２）中、Ｒ₁₁は、アルキレン基、アリーレン基、又はアラルキレン基を表す。Ｍは、水素原子、アルカリ金属、アンモニウム、又は有機アンモニウムを表す。＊は、前記一般式（１）中のベンゼン環との結合部位を表す）

(In the general formula (2), R ₁₁ represents an alkylene group, an arylene group, or an aralkylene group. M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium. * Represents the general formula (1). ) Represents the binding site with the benzene ring in

（前記一般式（３）中、Ｒ₁₂は、アルキル基、シクロアルキル基、アリール基、アラルキル基、アルケニル基、又はヘテロ環基を表す。＊は、前記一般式（１）中のベンゼン環との結合部位を表す）

(In the general formula (3), R ₁₂ represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, or a heterocyclic group. * Represents a benzene ring in the general formula (1). Represents the binding site of

  ADVANTAGE OF THE INVENTION According to this invention, the ink set containing the ink which can record the image excellent in coloring property, light resistance, and moisture resistance can be provided. Furthermore, it is possible to provide an ink set capable of recording an image excellent in bleeding resistance and capable of recording a secondary color image excellent in color developability (particularly in the color reproduction range of a dark portion). Moreover, according to the present invention, an ink jet recording method using this ink set can be provided.

2 is a chart showing the results of ¹ H NMR analysis of Exemplary Compound 1. 3 is a chart showing the results of ¹ H NMR analysis of Exemplary Compound 2. 3 is a chart showing the results of ¹ H NMR analysis of Exemplary Compound 3. 3 is a chart showing the results of ¹ H NMR analysis of Exemplary Compound 4. 4 is a chart showing the results of ¹ H NMR analysis of Exemplary Compound 5. 6 is a chart showing the results of ¹ H NMR analysis of Exemplary Compound 6. It is a chart which shows the result of UV / Vis spectroscopy analysis (in water, temperature 25 degreeC) of each compound synthesize | combined. FIG. 2 is a diagram schematically illustrating an example of an ink jet recording apparatus used in the ink jet recording method of the present invention, in which (a) is a perspective view of a main part of the ink jet recording apparatus, and (b) is a perspective view of a head cartridge.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. In the present invention, when the compound is a salt, the salt is dissociated into ions in the ink, but is expressed as “contains a salt” for convenience. Ink jet ink may be simply referred to as “ink”. Further, the physical property values are values at normal temperature (25 ° C.) unless otherwise specified.

  The present inventors have developed color development, light resistance, and moisture resistance of an image recorded with magenta ink, and color development of a secondary color image recorded using both black ink and magenta ink (color reproduction range of dark part). ) And the configuration of the ink set that improves. Furthermore, the configuration of an ink set that improves bleeding resistance at the boundary portion of an image recorded by using both black ink and magenta ink was studied. C. I. An image recorded with an ink containing Acid Red 289 as a colorant has a relatively low light resistance. Therefore, specifically, C.I. I. As a result of investigating the structure of a colorant capable of recording an image having a color development property equivalent to that of using Acid Red 289 and capable of recording an image with improved light resistance, the compound represented by the general formula (1) is obtained. I found it. Furthermore, it was found that by using the compound represented by the general formula (1) as a coloring material for magenta ink (second ink), a monochrome image with improved color development, light resistance and moisture resistance can be recorded on glossy paper. It was. In addition, this second ink is used in combination with a black ink (first ink) containing a self-dispersing pigment in which an ionic group is chemically bonded to the pigment particle surface directly or through another atomic group. did. As a result, it has also been found that a secondary color image having excellent color developability and particularly a color reproduction range in a dark portion can be recorded on plain paper, and an image having improved bleeding resistance at the boundary portion can be recorded. By using the ink set of the present invention having such a combination of the first ink and the second ink, the color developability of the secondary color image is improved and the bleeding resistance at the boundary portion of the image is improved. The present inventors presume as follows.

  Self-dispersed pigments in which ionic groups are chemically bonded to the pigment particle surface directly or via other atomic groups were applied to the recording medium as compared to resin-dispersed pigments dispersed with resin. The later cohesion is high. In addition, since the compound represented by the general formula (1) is a color material having a group represented by the general formula (2) that is a group containing a carboxy group, the fixing property to the recording medium and the recording The cohesive force after being applied to the medium is high. For this reason, when a secondary color image is recorded using both the first ink and the second ink, the self-dispersing pigment aggregates in the region where the recording medium is dyed by the second ink, and the aggregate of the pigment is formed in an island shape. Thus, the reflected light of the secondary color image is suppressed. Moreover, since the reflected light is maintained without impairing the spectral characteristics of the second ink, it is considered that the color reproduction range in the dark part of the secondary color image is expanded and the color developability is improved. Further, since the color material in the second ink has high fixability to the recording medium, the moisture resistance of the recorded image is improved and the image recorded by using the first ink and the second ink together is improved. It is considered that bleeding resistance at the boundary is also improved.

<Ink set>
The ink set of the present invention has a combination of a first ink and a second ink. The ink set of the present invention may further include ink other than the first ink and the second ink. The ink set of the present invention is particularly suitable as an ink set for inkjet. As the form of the ink set of the present invention, (i) a set of a plurality of ink cartridges containing each ink independently, and (ii) a plurality of ink containing parts containing each ink independently are combined and integrated. There are ink cartridges and the like. However, the ink set of the present invention is not limited to the above forms (i) and (ii) as long as the ink set can be used in combination with the first ink and the second ink. Hereinafter, the components contained in the first ink (black ink) and the second ink (magenta ink) constituting the ink set of the present invention, the physical properties of the ink, and the like will be described in detail.

(Color material of the first ink: self-dispersing pigment)
The first ink constituting the ink set of the present invention contains, as a coloring material, a self-dispersing pigment in which an ionic group is chemically bonded to the pigment particle surface directly or via another atomic group. By using the self-dispersing pigment as the color material, it is not necessary to add a dispersant for dispersing the color material in the first ink, or the amount of the dispersant added can be reduced. Examples of the pigment type of the self-dispersing pigment include organic pigments and inorganic pigments such as carbon black, and any of those usable for ink jet inks can be used. In addition to the self-dispersing pigment, a dye or the like may be used in combination for purposes such as toning. The first ink is preferably a black ink using carbon black as a pigment. The content (mass%) of the pigment in the first ink is preferably 0.10 mass% or more and 15.00 mass% or less, based on the total mass of the first ink, and is 1.00 mass% or more and 10. More preferably, it is 00 mass% or less.

  Examples of the ionic group chemically bonded to the pigment particle surface directly or through another atomic group include anionic groups such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phosphonic acid group. Can be mentioned. These anionic groups may form a salt. The anionic group may be either partially dissociated or completely dissociated. Examples of counter ions that form salts include alkali metals such as lithium, sodium, and potassium; unsubstituted ammonium; cations such as organic ammonium. Other atomic groups (—R—) include linear or branched alkylene groups having 1 to 12 carbon atoms, arylene groups such as phenylene groups and naphthylene groups, amide groups, sulfonyl groups, amino groups, and imino groups. , A carbonyl group, an ester group, an ether group, and a group obtained by combining these groups.

(Coloring material of second ink: compound represented by general formula (1))
The second ink constituting the ink set of the present invention contains a compound represented by the following general formula (1) as a coloring material (dye). The content (% by mass) of the compound represented by the general formula (1) in the second ink is preferably 0.10% by mass or more and 10.00% by mass or less based on the total mass of the ink. More preferably, it is 10 mass% or more and 5.00 mass% or less. If the content of the compound represented by the general formula (1) is less than 0.10% by mass, the color developability and light resistance of the image may be insufficient. On the other hand, if the content of the compound represented by the general formula (1) exceeds 10.00% by mass, characteristics such as ink sticking resistance may be insufficient.

（前記一般式（１）中、Ｒ₁、Ｒ₅、Ｒ₆及びＲ₁₀は、それぞれ独立に、アルキル基を表す。Ｒ₃及びＲ₈は、それぞれ独立に、水素原子、アルキル基、アルコキシ基、アリールオキシ基、又はイオン性基を表す。Ｒ₂、Ｒ₄、Ｒ₇及びＲ₉は、それぞれ独立に、水素原子、イオン性基、下記一般式（２）で表される基、又は下記一般式（３）で表される基を表し、Ｒ₂、Ｒ₄、Ｒ₇及びＲ₉は、少なくとも１つが下記一般式（２）で表される基である。ｎは、０乃至６の整数を表す。Ｚは、それぞれ独立に、スルホン酸基又はスルファモイル基を表す。ｎが１乃至６の整数である場合、Ｚは、芳香環に結合している）

(In the general formula (1), R ₁ , R ₅ , R ₆ and R ₁₀ each independently represents an alkyl group. R ₃ and R ₈ each independently represent a hydrogen atom, an alkyl group or an alkoxy group. R ₂ , R ₄ , R ₇ and R ₉ each independently represent a hydrogen atom, an ionic group, a group represented by the following general formula (2), or the following: R ₂ , R ₄ , R ₇ and R ₉ each represents a group represented by the following general formula (2), wherein n is 0 to 6 Z represents each independently a sulfonic acid group or a sulfamoyl group. When n is an integer of 1 to 6, Z is bonded to an aromatic ring)

（前記一般式（２）中、Ｒ₁₁は、アルキレン基、アリーレン基、又はアラルキレン基を表す。Ｍは、水素原子、アルカリ金属、アンモニウム、又は有機アンモニウムを表す。＊は、前記一般式（１）中のベンゼン環との結合部位を表す）

(In the general formula (2), R ₁₁ represents an alkylene group, an arylene group, or an aralkylene group. M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium. * Represents the general formula (1). ) Represents the binding site with the benzene ring in

（前記一般式（３）中、Ｒ₁₂は、アルキル基、シクロアルキル基、アリール基、アラルキル基、アルケニル基、又はヘテロ環基を表す。＊は、前記一般式（１）中のベンゼン環との結合部位を表す）

(In the general formula (3), R ₁₂ represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, or a heterocyclic group. * Represents a benzene ring in the general formula (1). Represents the binding site of

The compound represented by the general formula (1) is a color material having a structure in which a benzene ring is bonded to a xanthene skeleton via an amino group. An alkyl group is bonded to the ortho position (R ₁ , R ₅ , R ₆ , R ₁₀ ) of the benzene ring bonded to the xanthene skeleton with reference to the bonding position of the amino group. Furthermore, a specific substituent is bonded to at least one of the meta positions (R ₂ , R ₄ , R ₇ , R ₉ ). That is, in the compound represented by the general formula (1), the group represented by the general formula (2) which is a group containing a carboxy group is bonded to the meta position of the benzene ring based on the bonding position of the amino group. ing. For this reason, when an ink containing this compound as a coloring material is used, an image excellent in moisture resistance can be recorded.

In general formula (1), R ₁ , R ₅ , R ₆ and R ₁₀ each independently represents an alkyl group. Examples of the alkyl group represented by R ₁ , R ₅ , R ₆ and R ₁₀ include linear or branched alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. The alkyl group may have a substituent as long as the color developability, light resistance, and moisture resistance of the recorded image are not impaired. Examples of such a substituent include a hydroxy group; an alkoxy group having 1 to 3 carbon atoms such as a methoxy group, an ethoxy group, and a propoxy group; a cyano group; a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom; Can do. As the alkyl group, including those having a substituent, a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, 1-methylbutyl group And unsubstituted alkyl groups such as n-pentyl group and n-hexyl group; substituted alkyl groups such as 2-hydroxyethyl group, 2-methoxyethyl group, 2-cyanoethyl group and trifluoromethyl group; From the viewpoint of obtaining better light resistance and moisture resistance, the alkyl group preferably has 1 to 6 carbon atoms. Furthermore, from the viewpoint of ease of synthesis, the alkyl group preferably has 1 to 3 carbon atoms, and particularly preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group.

In general formula (1), R ₃ and R ₈ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, or an ionic group. The alkyl group, alkoxy group, and aryloxy group may have a substituent as long as the color developability, light resistance, and moisture resistance of the recorded image are not impaired. Examples of such a substituent include an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group; an aryl group having 6 to 12 carbon atoms such as a phenyl group and a naphthyl group; Aralkyl group having 7 to 14 carbon atoms such as p-tolyl group, m-xylyl group, 2-phenethyl group, naphthylethyl group; hydroxy group; carbamoyl group; sulfamoyl group; methoxy group, ethoxy group, n-propoxy group, C1-C3 alkoxy group such as isopropoxy group; cyano group; halogen atom such as fluorine atom, chlorine atom and bromine atom; ionic group such as carboxylic acid group, sulfonic acid group, phosphoric acid group and phosphonic acid group And the like.

Examples of the alkyl group represented by R ₃ and R ₈ include linear or branched alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. As the alkyl group, including those having a substituent, a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, 1-methylbutyl group An unsubstituted alkyl group such as n-pentyl group and n-hexyl group; 2-hydroxyethyl group, 2-methoxyethyl group, 2-cyanoethyl group, trifluoromethyl group, 3-sulfopropyl group, 4-sulfobutyl group, And substituted alkyl groups such as 4-carboxybutyl group. From the viewpoint of obtaining better moisture resistance, the alkyl group preferably has 1 to 6 carbon atoms. Further, from the viewpoint of obtaining better color developability and moisture resistance, the alkyl group preferably has 1 to 3 carbon atoms, and particularly preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group.

Examples of the alkoxy group represented by R ₃ and R ₈ include linear or branched alkoxy groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. As the alkoxy group, including those having a substituent, unsubstituted alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, and an isopropoxy group; a 2-methoxyethoxy group, a 2-hydroxyethoxy group, and a 3-carboxy group And a substituted alkoxy group such as a propoxy group. The number of carbon atoms of the alkoxy group is preferably 1 to 6 from the viewpoint of obtaining better color developability. Furthermore, it is particularly preferable that the alkoxy group has 1 to 3 carbon atoms, since more excellent color developability is obtained and water solubility is also improved.

Examples of the aryloxy group represented by R ₃ and R ₈ include aryloxy groups having 6 to 18 carbon atoms, preferably 6 to 12 carbon atoms, and particularly preferably 6 to 10 carbon atoms. The aryloxy group of R ₃ and R ₈ includes those having a substituent, such as phenoxy group, 2-naphthoxy group, 1-anthryloxy group, 9-phenanthryloxy group, 1-azurenyloxy group, etc. Unsubstituted aryloxy group; p-methoxyphenoxy group, o-methoxyphenoxy group, o-tolyloxy group, p-tolyloxy group, 2,3-xylyloxy group, 3,5-xylyloxy group, 4-carboxy-2-methylphenoxy Group, substituted aryloxy groups such as 4-sulfo-2-methylphenoxy group; and the like. The number of carbon atoms of the aryloxy group is preferably 6 to 18 and more preferably 6 to 12 from the viewpoint of obtaining better moisture resistance. Among them, a phenoxy group is preferable from the viewpoint of easy synthesis, as well as better color developability and moisture resistance.

Examples of the ionic group represented by R ₃ and R ₈ include anionic groups such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phosphonic acid group. The ionic group gives water solubility to the compound represented by the general formula (1) together with other ionic groups and sulfamoyl groups that may be present. The ionic group may be either acid type or salt type. When the ionic group is in a salt form, the counter ions that form the salt include alkali metals such as lithium, sodium, and potassium; unsubstituted ammonium; methylammonium, dimethylammonium, trimethylammonium, tetramethylammonium, ethylammonium, Organic ammonium such as diethylammonium, triethylammonium, tetraethylammonium, n-propylammonium, isopropylammonium, diisopropylammonium, n-butylammonium, tetran-butylammonium, isobutylammonium, monoethanolammonium, diethanolammonium, triethanolammonium; Can be mentioned. Not only the ionic groups represented by R ₃ and R ₈ but also other ionic groups that the compound represented by the general formula (1) may have either an acid form or a salt form. When the other ionic group is a salt type, examples of the counter ion that forms a salt include the same counter ions as those described above.

In general formula (1), R ₃ and R ₈ are each independently an alkyl group having 1 to 3 carbon atoms in order to further improve the color developability and moisture resistance of the recorded image. And more preferably a group, an ethyl group, an n-propyl group, or an isopropyl group. From the viewpoint of ease of synthesis, when R ₃ and R ₈ have a substituent, it is preferable that all the groups have the same substituent.

In general formula (1), R ₂ , R ₄ , R ₇ and R ₉ are each independently a hydrogen atom, an ionic group, a group represented by general formula (2), or a general formula (3). Represents a group. R ₂ , R ₄ , R ₇ and R ₉ are at least one group represented by the general formula (2). The number of groups represented by the general formula (2) in the general formula (1) is preferably 2 or more and 4 or less.

The compound represented by the general formula (1) is C.I. I. Similar to Acid Red 289, it is a coloring material (dye) having a high magenta coloring property. And if the compound represented by General formula (1) is used as a coloring material, the image excellent in light resistance and moisture resistance can be recorded. In order to obtain such an effect, it is important that at least one of R ₂ , R ₄ , R ₇ and R _{9 in} the general formula (1) is a group represented by the general formula (2).

Examples of the ionic group represented by R ₂ , R ₄ , R ₇ and R ₉ include anionic groups such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and a phosphonic acid group. The ionic group gives water solubility to the compound represented by the general formula (1) together with other ionic groups and sulfamoyl groups that may be present. The ionic group may be either acid type or salt type. When the ionic group is in a salt form, the counter ion that forms a salt is a specific example of the counter ion that forms a salt when the ionic group represented by R ₃ and R ₈ is in the salt form. The same thing can be mentioned.

The group represented by the general formula (2) is a group having a structure in which an amide group and a carboxylic acid group are linked via R ₁₁ as a linker. R ₁₁ represents an alkylene group, an arylene group, or an aralkylene group. M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium.

R ₁₁ in the general formula (2) may have a substituent as long as the color developability, light resistance, and moisture resistance of the recorded image are not impaired. Examples of such substituents include alkyl groups having 1 to 3 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group; a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. A cycloalkyl group having 3 to 8 carbon atoms such as cyclooctyl group; cyclopropylene group, cyclobutylene group, cyclopentylene group, cyclohexylene group, dimethylcyclohexylene group, methylcycloheptylene group, cyclooctylene group And a cycloalkylene group having 3 to 8 carbon atoms such as an alkoxy group having 1 to 3 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, and an isopropoxy group. Furthermore, the hydrogen atom of these substituents may be replaced with a substituent having a carbon number equal to or less than that of the substituent (such as a linear or branched alkyl group).

Examples of the alkylene group represented by R ₁₁ include linear or branched alkylene groups having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. The alkylene group is a straight chain such as methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, etc. Alkylene group; 2-methyl-n-pentylene group, 3-methyl-n-pentylene group, 4-methyl-n-pentylene group, 1,1-dimethyl-n-butylene group, 1,2-dimethyl-n-butylene Group, 1,3-dimethyl-n-butylene group, 2,2-dimethyl-n-butylene group, 2,3-dimethyl-n-butylene group, 3,3-dimethyl-n-butylene group, 1-ethyl- n-butylene group, 2-ethyl-n-butylene group, 1,1,2-trimethyl-n-propylene group, 1,2,2-trimethyl-n-propylene And the like; group, 1-ethyl-1-methyl -n- propylene group, 1-ethyl-2-methyl -n- propylene group, branched alkylene groups such as sec- decylene. Since the moisture resistance of the image is further improved and the water solubility of the compound represented by the general formula (1) is improved, the alkylene group preferably has 1 to 10 carbon atoms. Furthermore, the carbon number of the alkylene group is particularly preferably 3 to 8 in order to further improve the color developability of the image.

Examples of the arylene group represented by R ₁₁ include monocyclic or polycyclic arylene groups having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms. Examples of the arylene group include a phenylene group, a biphenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, and an azulylene group.

Examples of the aralkylene group represented by R ₁₁ include a group obtained by combining the above arylene group and alkylene group. Among them, an aralkylene group in which a phenylene group and an alkylene group having 1 to 6 carbon atoms are bonded is preferable, and an aralkylene group in which a phenylene group and a propylene group are bonded is more preferable.

  Examples of the alkali metal represented by M include lithium, sodium, and potassium. Examples of the organic ammonium represented by M include methylammonium, dimethylammonium, trimethylammonium, tetramethylammonium, ethylammonium, diethylammonium, triethylammonium, tetraethylammonium, n-propylammonium, isopropylammonium, diisopropylammonium, n-butylammonium. Tetra n-butylammonium, isobutylammonium, monoethanolammonium, diethanolammonium, triethanolammonium and the like.

In general formula (2), R ₁₁ is preferably a group having a structure in which a cycloalkylene is bonded to a carbon atom constituting an alkylene group in order to further improve the moisture resistance of the recorded image. That is, in the case where R ₁₁ represents “cycloalkylene” as “circle” as shown in the following general formula (a), one of the carbon atoms constituting the cycloalkylene is shared with the carbon atom of the alkylene group. It is preferably a group having a structure. The number of carbon atoms of the alkylene group (in general formula (a), x + y + 1) is preferably 2 to 10, and more preferably 3 to 8. Especially, it is preferable that an alkylene group is a propylene group (namely, carbon number is 3). The cycloalkylene preferably has 3 to 8 carbon atoms. Especially, since the moisture resistance of an image improves further and the water solubility of the compound represented by General formula (1) also becomes favorable, it is preferable that carbon number of cycloalkylene is 4-8. In addition, it is more preferable that the cycloalkylene has 5 to 8 carbon atoms from the viewpoint of improving the color developability of the image and ease of synthesis. More specifically, R ₁₁ in the general formula (2) is particularly preferably a group having a structure in which cyclohexylene is bonded to the carbon atom at the 2-position of the propylene group.

（一般式（ａ）中、「円」は、シクロアルキレンを表す。ｘ及びｙは、それぞれ独立に、０以上の整数を表し、ｘ＋ｙは１以上の整数である）

(In general formula (a), “circle” represents cycloalkylene. X and y each independently represents an integer of 0 or more, and x + y is an integer of 1 or more.)

R ₁₁ in the general formula (2) is preferably an aralkylene group having a substituent in order to further improve image color development and moisture resistance. Examples of the substituent include alkyl groups such as methyl group, ethyl group, n-propyl group, and isopropyl group; alkoxy groups such as methoxy group, ethoxy group, n-propoxy group, and isopropoxy group; carboxylic acid group, sulfonic acid group, And ionic groups such as a phosphoric acid group and a phosphonic acid group. Of these, an isopropyl group, an ethoxy group, a t-butoxy group, and a carboxylic acid group (may be a salt type) are preferable.

Since the light resistance of the recorded image is particularly improved, it is preferable that R ₃ and R _{8 in} the general formula (1) and R _{11 in the} general formula (2) are combinations shown below. That is, R ₃ and R ₈ are preferably a hydrogen atom, an unsubstituted alkyl group, an unsubstituted alkoxy group, or an unsubstituted aryloxy group. R _{11 in the} general formula (2) is a group having a structure in which a cycloalkylene having 5 to 8 carbon atoms is bonded to a carbon atom constituting an alkylene group propylene group having 3 to 8 carbon atoms, or a phenylene group and a propylene group are A bonded unsubstituted aralkylene group is preferred.

The group represented by the general formula (3) is an acylamino group to which R ₁₂ (an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, or a heterocyclic group) is bonded. R ₁₂ may have a substituent as long as the color developability, light resistance, and moisture resistance of the recorded image are not impaired. Examples of such a substituent include an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group; an aryl group having 6 to 12 carbon atoms such as a phenyl group and a naphthyl group; , Aralkyl groups having 7 to 14 carbon atoms such as p-tolyl group, xylyl group, 2-phenethyl group, naphthylethyl group; vinyl group, 1-propenyl group, 2-propenyl group, 1-methylethenyl group, 1-butenyl group Alkenyl groups having 2 to 4 carbon atoms such as 2-butenyl group and 3-butenyl group; alkoxy groups having 1 to 3 carbon atoms such as methoxy group, ethoxy group, n-propoxy group and isopropoxy group; cyano group; methyl An alkylamino group having 1 to 3 carbon atoms such as amino group, ethylamino group, n-propylamino group, isopropylamino group; carbamoyl group; Niruamino group; fluorine atom, a chlorine atom, a halogen atom such as a bromine atom; and the like; carboxylic acid group, a phosphoric acid group, the ionic group such as a phosphonic acid group.

Examples of the alkyl group represented by R ₁₂ include linear or branched alkyl groups having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms. As the alkyl group, including those having a substituent, a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, 1-methylbutyl group N-pentyl group, isopentyl group, sec-pentyl group, neopentyl group, tert-pentyl group, n-hexyl group, sec-hexyl group, n-heptyl group, sec-heptyl group, n-octyl group, 2-ethylhexyl Group, sec-octyl group, n-nonyl group, sec-nonyl group, n-decyl group, sec-decyl group, n-undecyl group, sec-undecyl group, n-dodecyl group, sec-dodecyl group, tridecyl group, Isotridecyl group, sec-tridecyl group, tetradecyl group, sec-tetradecyl group, hexadecyl group, sec- Xadecyl group, n-stearyl group, 2-butyloctyl group, 2-butyldecyl group, 2-hexyloctyl group, 2-hexyldecyl group, 2-octyldecyl group, 2-hexyldecyl group, 2-octyldodecyl group, 2 -Unsubstituted alkyl groups such as hexadecyl group and octadecyl group; 2-hydroxyethyl group, 2-methoxyethyl group, 2-cyanoethyl group, trifluoromethyl group, 3-sulfopropyl group, 4-sulfobutyl group, 4-carboxybutyl A substituted alkyl group such as a group;

Examples of the cycloalkyl group represented by R ₁₂ include a monocyclic or multicyclic cycloalkyl group having 3 to 18 carbon atoms, preferably 5 to 12 carbon atoms. As the cycloalkyl group, including those having a substituent, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a bornyl group, an isobornyl group, a 1-norbornyl group, 1-bicyclo [2.2 .2] Octyl group, 1-adamantyl group, 3-noradamantyl group, cyclooctyl group, cyclodecyl group, cyclododecyl group, cyclotetradecyl group, cyclopentadecyl group, cyclohexadecyl group, cycloheptadecyl group, cyclooctadecyl group Unsubstituted cycloalkyl groups such as 1-isopropylcyclohexyl group, 1-adamantylmethyl group, 2,3-dimethylcyclohexyl group, 2,5-dimethylcyclohexyl group, 2,6-dimethylcyclohexyl group, 3,4-dimethyl group Cyclohexyl group, 3,5 Substitution of dimethylcyclohexyl group, 2,4,6-trimethylcyclohexyl group, 3,3,5-trimethylcyclohexyl group, 2,6-diisopropylcyclohexyl group, 4-tert-butylcyclohexyl group, 3-tert-butylcyclohexyl group, etc. A cycloalkyl group;

Examples of the aryl group represented by R ₁₂ include monocyclic or multicyclic aryl groups having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms. As the aryl group, including those having a substituent, an unsubstituted aryl group such as a phenyl group, a biphenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an azulenyl group; a p-methoxyphenyl group, an o-chlorophenyl group, m A substituted aryl group such as-(3-sulfopropylamino) phenyl group and o-carboxyphenyl group;

Examples of the aralkyl group represented by R ₁₂ include aralkyl groups having 7 to 14 carbon atoms, preferably 7 to 10 carbon atoms. Examples of the aralkyl group include a benzyl group, a p-tolyl group, a xylyl group, a 2-phenethyl group, and a naphthylethyl group.

Examples of the alkenyl group represented by R ₁₂ include linear or branched alkenyl groups having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms. Examples of the alkenyl group include a vinyl group, 1-propenyl group, 2-propenyl group, 1-methylethenyl group, 1-butenyl group, 2-butenyl group, and 3-butenyl group.

The heterocyclic group represented by R ₁₂ is preferably a 5-membered or 6-membered heterocyclic group. Examples of the hetero atom contained in the heterocyclic group include a nitrogen atom, an oxygen atom, and a sulfur atom. The heterocyclic group may be condensed with an aliphatic ring, an aromatic ring, and another heterocyclic ring. Heterocyclic groups include imidazolyl, benzoimidazolyl, pyrazolyl, benzopyrazolyl, triazolyl, thiazolyl, benzothiazolyl, isothiazolyl, benzisothiazolyl, oxazolyl, benzoxazolyl, thiadiazolyl, pyrrolyl Group, benzopyrrolyl group, indolyl group, isoxazolyl group, benzoisoxazolyl group, thienyl group, benzothienyl group, furyl group, benzofuryl group, pyridyl group, quinolyl group, isoquinolyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, cinnolinyl Group, phthalazinyl group, quinazolinyl group, quinoxalinyl group, triazinyl group and the like.

From the viewpoint of ease of synthesis of the compound represented by the general formula (1), R ₁ and R ₆ , R ₂ and R ₇ , R ₃ and R ₈ , R ₄ and R ₉ , and R ₅ and R ₁₀ are These are preferably the same groups.

  In general formula (1), n represents an integer of 0 to 6. n means the number of groups represented by Z in the general formula (1) (the number of substitutions). That is, when n = 0, the compound represented by the general formula (1) does not have a sulfonic acid group or a sulfamoyl group represented by Z. The compound represented by the general formula (1) may have n = 0 because water solubility is imparted by the carboxylic acid group contained in the group represented by the general formula (2). However, n is preferably an integer of 1 or more in order to improve water solubility, and n is preferably an integer of 3 or less in order to further improve the moisture resistance of the image. n is determined by the substitution position of each substituent in the general formula (1) and the conditions of the sulfonation reaction or chlorosulfonation reaction. The compound represented by the general formula (1) may be a mixture of a plurality of compounds having different numbers of n.

In general formula (1), Z represents a sulfonic acid group or a sulfamoyl group each independently. When n is an integer of 1 to 6, Z is bonded to the aromatic ring. The sulfonic acid group represented by Z has a role of imparting water solubility to the compound represented by the general formula (1) together with an ionic group and a sulfamoyl group that may be present. The sulfonic acid group may be either acid type or salt type. When the sulfonic acid group is in a salt form, specific examples of counter ions that form a salt include counter ions that form a salt when the ionic groups represented by R ₃ and R ₈ are in a salt form. The same thing as the specific example of can be mentioned.

  The sulfamoyl group represented by Z may have a substituent as long as the color developability, light resistance, and moisture resistance of the recorded image are not impaired. Examples of such a substituent include alkyl groups having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and a butyl group. As the sulfamoyl group, including those having a substituent, an unsubstituted sulfamoyl group (aminosulfonyl group); N-methylaminosulfonyl group, N, N-dimethylaminosulfonyl group, Nn-butylaminosulfonyl group, etc. And sulfamoyl group substituted with an alkyl group having 1 to 4 carbon atoms.

  It is preferable that the compound represented by the general formula (1) has an ionic group because the water solubility of the compound represented by the general formula (1) can be further increased. More specifically, in general formula (1), n is an integer of 1 to 6, and Z is preferably a sulfonic acid group. Further, in the general formula (1), Z is a salt-type sulfonic acid group, and the counter ion forming the salt is at least one selected from the group consisting of lithium ions, sodium ions, potassium ions, and ammonium ions. Preferably there is.

The substitution position of Z in the main skeleton of the compound represented by the general formula (1) (that is, the structure in parentheses ([]) in the general formula (1)) is the position of other substituents in the general formula (1). It is determined by the bonding position and the conditions of the sulfonation reaction or chlorosulfonation reaction. In general formula (1), R ₂ , R ₃ , R ₄ , R ₇ , R ₈ and R ₉ are all groups other than hydrogen atoms, and R ₁₁ or R ₁₂ has an aromatic hydrogen atom. If not, Z is bonded to the xanthene skeleton. Further, when at least one of R ₂ , R ₃ , R ₄ , R ₇ , R ₈ and R ₉ has an aromatic hydrogen atom, Z may be bonded (substituted) to the position of the hydrogen atom. . Further, when R ₁₁ or R ₁₂ has an aromatic ring having an aromatic hydrogen atom, Z may be bonded to this aromatic ring. From the viewpoint of ease of synthesis, it is preferable that Z is bonded to the hydrogen atom position of the xanthene skeleton.

The compound represented by the general formula (1) has tautomers. Examples of the tautomer include compounds represented by the following general formulas (1a) and (1b) in addition to the compound represented by the general formula (1). In the present invention, these compounds (tautomers) and salts are also included in the compound represented by the general formula (1). Incidentally, R ₁ to R ₁₀ in the following general formula (1a) and (1b), Z, and n have the same meanings as R ₁ to R _10, Z, and n in the general formula (1).

The compound represented by the general formula (1) can be synthesized based on a known method. An example of a synthesis scheme is shown below. Compound in Synthesis Scheme (B), (C), (D) and (E) in the R ₁ to R _10, Z, and n have the general formula (1) of R ₁ to R _10, Z, and It is synonymous with n. In addition, the compound represented by the general formula (1) can be synthesized as a mixture of a plurality of isomers having different types, the number, and positions of substituents. However, for convenience, in the present invention, including a mixture, Described as “compound”.

  In the above synthesis scheme, the compound represented by the general formula (1) where n = 0 is synthesized through the first condensation step shown in the first step and the second condensation step shown in the second step. In order to further increase the water solubility of the compound represented by the general formula (1), a sulfonation or sulfamoylation step may be added. When a sulfonation or sulfamoylation step is added, a compound represented by the general formula (1) where n = 1 to 6 can be obtained.

  In the first condensation step, compound (C) is obtained by heating compound (A) and compound (B) in the presence of an organic solvent or a condensing agent to condense. In the second condensation step, compound (D) and compound (C) obtained in the first condensation step are heated and condensed to give compound (E) (general formula (1) where n = 0. ) Is obtained. In order to further increase the water solubility, the compound (E) obtained in the second condensation step is sulfonated using a sulfonating agent such as concentrated sulfuric acid or fuming sulfuric acid. Thereby, the compound (F) (compound represented by General formula (1) which is n = 1-6) whose Z is a sulfonic acid group can be obtained. In addition, if the compound (E) obtained in the second condensation step is chlorosulfonated using chlorosulfonic acid or the like and then reacted with amine compounds such as concentrated aqueous ammonia, alkylamine, and arylamine, sulfamoyl Can be Thereby, the compound (F) (compound represented by General formula (1) which is n = 1-6) whose Z is a sulfamoyl group can be obtained.

  Examples of the organic solvent that can be used in the first condensation step include methanol, ethanol, n-propanol, isopropanol, and n-butanol. A mixture of a plurality of these organic solvents may be used. Examples of the organic solvent that can be used in the second condensation step include ethylene glycol, N-methylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, chlorobenzene, dichlorobenzene, Examples include chlorobenzene and nitrobenzene. A mixture of a plurality of these organic solvents may be used.

  The reaction temperature in the first condensation step is preferably 60 ° C. or higher and 100 ° C. or lower, and more preferably 70 ° C. or higher and 90 ° C. or lower. The reaction temperature in the second condensation step is preferably 120 ° C. or higher and 220 ° C. or lower, and more preferably 180 ° C. or lower.

When synthesizing a compound in which R _{1 to} R ₅ and R _{6 to} R _{10 in the} general formula (1) are the same group, the compound (B) and the compound (D) in the above synthesis scheme are the same compound. . For this reason, if a one-step condensation process is carried out from the compound (A), the compound represented by the general formula (1) can be obtained. The reaction temperature for carrying out the one-stage condensation step is preferably 120 ° C. or higher and 220 ° C. or lower, and more preferably 180 ° C. or lower. As the condensing agent, for example, magnesium oxide, zinc chloride, aluminum chloride or the like can be used.

The compound which is the final product obtained by the above synthesis scheme is processed in accordance with a post-treatment method of a normal organic synthesis reaction, and then purified, so that it can be used in a desired application such as an ink coloring material (dye). can do. The structure of the compound represented by the general formula (1) can be identified by ¹ H NMR analysis, LC / MS analysis, UV / Vis spectroscopic analysis and the like.

  Preferable examples of the compound represented by the general formula (1) include exemplified compounds 1 to 39 shown in Tables 1 to 3. In the present invention, the compound represented by the general formula (1) is not limited to the exemplified compounds shown below as long as it is included in the structure and definition of the compound represented by the general formula (1). As the compound represented by the general formula (1), Exemplified Compounds 1 to 6 are preferable among the exemplified compounds shown below. In Tables 1 to 3, “Me” represents methyl, “Et” represents ethyl, “n-Pr” represents normal propyl, “i-Pr” represents isopropyl, and “t-Bu” represents tertiary butyl. “*” Represents the bonding position of the substituent.

(Color material of the second ink: other color materials)
The second ink preferably contains a compound other than the compound represented by the general formula (1) as a coloring material. Inclusion of a compound (other colorant) other than the compound represented by the general formula (1) further improves the light resistance without impairing the excellent color developability of the compound represented by the general formula (1). Ink can be recorded on the printed image.

Examples of other colorants include pigments and dyes. Among these, it is preferable to use a dye. As other color materials, materials of any hue classified into cyan, magenta, yellow, red, blue, green, black and the like may be used. In particular, it is preferable to use a dye having a hue of magenta to red, and it is more preferable to use a dye such as a compound having an azo skeleton or an anthrapyridone skeleton. More specifically, the maximum absorption wavelength (λ _max ) in water is preferably 380 to 590 nm, more preferably 480 to 570 nm, and particularly preferably 500 to 560 nm from the viewpoint of obtaining a further improvement effect of color developability. Use compounds present in the range.

  Examples of the compound having an azo skeleton include C.I. I. Examples include Acid Red 249 (Azo Compound 1) and those described in JP-A-8-073791, JP-A-2002-371214, JP-A-2006-143898, and the like. Specific examples include compounds represented by the following general formula (I) and compounds represented by the following general formula (II). Examples of the compound having an anthrapyridone skeleton include International Publication No. 1998/011167, International Publication No. 1998/011167, International Publication No. 2004/104108, International Publication No. 2009/060654, International Publication No. 2009/093433. And the like having a monomer structure described in the above. Furthermore, the thing of the dimer structure etc. which were described in international publication 2003027185, international publication 2006/0775706, international publication 2008/066062, Unexamined-Japanese-Patent No. 2010-006969 etc. can be mentioned. Specific examples include compounds represented by the following general formula (III) and compounds represented by the following general formula (IV).

  In the following general formulas (I) to (IV), the alkyl has preferably 1 to 6 carbon atoms, and the aryl has preferably 6 to 10 carbon atoms. In addition, a group having a carbon atom that may have a substituent is substituted with a substituent such as an alkyl group, an aryl group, a hydroxy group, a halogen atom, a cyano group, a carboxy group, a sulfonic acid group, an alkylsulfonyl group, and an anilino group. It may be.

（一般式（Ｉ）中、Ｒ₁〜Ｒ₄は、それぞれ独立に、水素原子、ハロゲン原子、シアノ基、カルボキシ基、ヒドロキシ基、スルホン酸基、又はアルキル基を表す）

(In general formula (I), R _{1 to} R ₄ each independently represents a hydrogen atom, a halogen atom, a cyano group, a carboxy group, a hydroxy group, a sulfonic acid group, or an alkyl group)

（一般式（ＩＩ）中、Ｒ₁〜Ｒ₈は、それぞれ独立に、水素原子、ハロゲン原子、シアノ基、カルボキシ基、ヒドロキシ基、スルホン酸基、又はアルキル基を表す）

(In general formula (II), R _{1 to} R ₈ each independently represents a hydrogen atom, a halogen atom, a cyano group, a carboxy group, a hydroxy group, a sulfonic acid group, or an alkyl group)

（一般式（ＩＩＩ）中、Ｒ₁は、アルキルカルボニル基、アルコキシカルボニル基、アリールカルボニル基、又はアリールオキシカルボニル基を表す。Ｒ₂は、水素原子又はアルキル基を表す。Ｒ₃は、アニリノ基を表す）

(In the general formula (III), R ₁ represents an alkylcarbonyl group, an alkoxycarbonyl group, an arylcarbonyl group, or an aryloxycarbonyl group. R ₂ represents a hydrogen atom or an alkyl group. R ₃ represents an anilino group. Represents)

（一般式（ＩＶ）中、Ｒ₁は、アルキルカルボニル基、アルコキシカルボニル基、アリールカルボニル基、又はアリールオキシカルボニル基を表す。Ｒ₂は、水素原子又はアルキル基を表す。Ｒ₃は、アニリノ基を表す。Ｒ₄は、連結基を表す）

(In the general formula (IV), R ₁ represents an alkylcarbonyl group, an alkoxycarbonyl group, an arylcarbonyl group, or an aryloxycarbonyl group. R ₂ represents a hydrogen atom or an alkyl group. R ₃ represents an anilino group. R ₄ represents a linking group)

  Specific examples of the compound having an azo skeleton include azo compounds 1 to 4 having the following structure (however, in a free acid state). Specific examples of the compound having an anthrapyridone skeleton include anthrapyridone compounds 1 to 9 having the following structure (however, in a free acid state).

(Aqueous medium)
Each ink constituting the ink set of the present invention may contain water or an aqueous medium that is a mixed solvent of water and a water-soluble organic solvent. Each ink is preferably an aqueous ink containing at least water as an aqueous medium. It is preferable to use deionized water (ion exchange water) as the water. The content (% by mass) of water in the ink is preferably 10.00% by mass or more and 90.00% by mass or less based on the total mass of the ink.

  The water-soluble organic solvent is not particularly limited as long as it is water-soluble, and alcohol, polyhydric alcohol, polyglycol, glycol ether, nitrogen-containing polar solvent, sulfur-containing polar solvent and the like can be used. The content (% by mass) of the water-soluble organic solvent in the ink is preferably from 5.00% by mass to 90.00% by mass based on the total mass of the ink, and from 10.00% by mass to 50.00%. More preferably, it is at most mass%. If the content of the water-soluble organic solvent is out of the above range, the ink ejection stability may be insufficient.

(Other additives)
In addition to the above-described components, each ink constituting the ink set of the present invention includes, if necessary, polyhydric alcohols such as trimethylolpropane and trimethylolethane; water-soluble organic solids at room temperature such as urea and derivatives thereof A compound may be contained. Furthermore, each ink constituting the ink set of the present invention includes a surfactant, a pH adjuster, a rust inhibitor, an antiseptic, an antifungal agent, an antioxidant, an anti-reduction agent, and an evaporation accelerator as necessary. Various additives such as a chelating agent and a water-soluble resin may be contained.

  The first ink and the second ink preferably contain a surfactant. The content (% by mass) of the surfactant in each ink is preferably 0.05% by mass or more and 2.00% by mass or less based on the total mass of the ink. The first ink preferably contains a surfactant such as acetylene glycol, fluorine, silicone, or polyoxyethylene alkyl ether. The second ink preferably contains an acetylene glycol surfactant. Among these, since the second ink is excellent in solubility in an aqueous medium, it is particularly preferable to contain an ethylene oxide adduct of acetylene glycol.

The first ink preferably contains a salt formed by combining a cation and an anion. By containing salt in the first ink, the optical density of an image recorded with the first ink can be improved. Furthermore, bleeding resistance at the boundary between the image recorded with the first ink and the image recorded with the second ink can be improved. Examples of the cation constituting the salt include alkali metal ions such as lithium ions, sodium ions, and potassium ions; ammonium ions; organic ammonium ions. Of these, potassium ion and ammonium ion are preferable. The anions constituting the salt include Cl ⁻ , Br ⁻ , I ⁻ , ClO ⁻ , ClO ₂ ⁻ , ClO ₃ ⁻ , ClO ₄ ⁻ , NO ₂ ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ , CO ₃ ^{2. _{-, HCO 3 -, HCOO -}} , (COO -) 2, COOH (COO -), CH 3 COO -, C 2 H 4 (COO -) 2, C 6 H 5 COO -, C 6 H 4 (COO - ₂ ), PO ₄ ³⁻ , HPO ₄ ²⁻ , H ₂ PO ₄ ^{− and the} like. The form of the salt in the ink may be in any of a dissociated state and a dissociated state.

  The first ink only needs to contain a salt in a range where the above-described effects can be obtained. Specifically, the salt content (% by mass) in the first ink is preferably 0.05% by mass or more and 10.00% by mass or less based on the total mass of the ink. If the salt content in the first ink exceeds 10.00% by mass, the storage stability of the ink may be insufficient. On the other hand, if the salt content in the first ink is less than 0.05% by mass, the above effects may be insufficient.

(Ink physical properties)
The static surface tension at 25 ° C. of each ink constituting the ink set of the present invention is preferably 10 mN / m or more and 60 mN / m or less. Further, it is more preferably 20 mN / m or more and 60 mN / m or less, and particularly preferably 30 mN / m or more and 40 mN / m or less. Each ink constituting the ink set of the present invention has a surface tension within the above-described range, so that when it is applied to an ink jet system, the ejection deviation due to wetting in the vicinity of the ejection opening (displacement of ink landing point), etc. Generation | occurrence | production can be suppressed effectively. The surface tension of the ink can be adjusted by appropriately setting the content of a surfactant or the like in the ink.

  The dynamic surface tension of the first ink at 25 ° C. and a lifetime of 50 milliseconds is preferably 40 mN / m or more, and more preferably 45 mN / m or more. By using the first ink having a dynamic surface tension in the above range, the pigment can be present particularly efficiently on the surface of the recording medium, and an image having a higher optical density can be recorded. The dynamic surface tension of the ink is measured by the maximum bubble pressure method. In the maximum bubble pressure method, the surface tension is obtained by measuring the maximum pressure required to release bubbles pushed out from the tip of a probe (thin tube) immersed in the liquid to be measured. “Lifetime” is the maximum bubble pressure method. When bubbles are formed from the tip of the probe, when a new surface is formed after the bubbles are released, the maximum bubble pressure (the radius of curvature of the bubble and the probe tip) Time until the radius of the part becomes equal).

  Each ink constituting the ink set of the present invention is preferably adjusted to a desired pH and viscosity so that good ejection characteristics can be obtained when applied to an ink jet recording apparatus. The pH at 25 ° C. of each ink constituting the ink set of the present invention is preferably 5.0 or more and 10.0 or less. The viscosity at 25 ° C. of each ink constituting the ink set of the present invention is preferably 1.0 mPa · s or more and 5.0 mPa · s or less.

<Inkjet recording method>
The ink jet recording method of the present invention is a method of recording an image on a recording medium by ejecting each ink constituting the ink set of the present invention described above from an ink jet recording head. Examples of the method for ejecting ink include a method for imparting mechanical energy to the ink and a method for imparting thermal energy to the ink. In the present invention, it is preferable to employ a method in which thermal energy is applied to the ink and the ink is ejected. Except for using each ink constituting the ink set of the present invention, the steps of the ink jet recording method and the constitution of the ink jet recording apparatus may be known ones.

  8A and 8B are diagrams schematically showing an example of an ink jet recording apparatus used in the ink jet recording method of the present invention. FIG. 8A is a perspective view of a main part of the ink jet recording apparatus, and FIG. 8B is a perspective view of a head cartridge. It is. The ink jet recording apparatus is provided with a conveying means (not shown) for conveying the recording medium 32 and a carriage shaft 34. A head cartridge 36 can be mounted on the carriage shaft 34. The head cartridge 36 includes recording heads 38 and 40, and is configured such that an ink cartridge 42 is set. While the head cartridge 36 is conveyed along the carriage shaft 34 in the main scanning direction, ink (not shown) is ejected from the recording heads 38 and 40 toward the recording medium 32. Then, the recording medium 32 is conveyed in the sub-scanning direction by a conveying unit (not shown), whereby an image is recorded on the recording medium 32.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited at all by the following Example, unless the summary is exceeded. In addition, what is described as “parts” and “%” with respect to the component amounts is based on mass unless otherwise specified.

<Preparation of pigment dispersion>
(Pigment dispersion A)
A solution prepared by dissolving 5 g of concentrated sulfuric acid in 5.5 g of water was cooled to 5 ° C., and 0.84 g (4.64 mmol) of 4-amino-1,2-benzenedicarboxylic acid was added. Potassium nitrite obtained by dissolving 2.2 g (26 mmol) of potassium nitrite in 9 g of water at 5 ° C. while the solution temperature is kept at 10 ° C. or lower while the container containing the solution is put in an ice bath. The solution was added. After further stirring for 15 minutes, 6 g of carbon black (trade name “Black Pearls 1100”, manufactured by Cabot) was added with stirring. Furthermore, the slurry obtained by stirring for 15 minutes was filtered with a filter paper (trade name “standard filter paper No. 2”, manufactured by Advantech) to obtain particles. The obtained particles were sufficiently cooled with water and then dried in an oven at 110 ° C. Subsequently, water was added to obtain a dispersion liquid in which a self-dispersing pigment having —C ₆ H ₃ — (COOH) ₂ groups bonded to the particle surface was dispersed with a pigment content of 10.0%. By replacing potassium ions with ammonium ions by an ion exchange method, a self-dispersing pigment having a pigment content of 10.0% and having —C ₆ H ₃ — (COONH ₄ ) ₂ groups bonded to the particle surface was dispersed. A pigment dispersion A was obtained.

(Pigment dispersion B)
Using a Silverson mixer, 20 g of carbon black (solid content), 9 mmol of ((4-aminobenzoylamino) -methane-1,1-diyl) bisphosphonic acid monosodium salt, 20 mmol of nitric acid, and 200 mL of pure water were mixed. did. As carbon black, a trade name “Black Pearls 880” (manufactured by Cabot) was used. Mixing was performed at 6,000 rpm under room temperature conditions. After 30 minutes, 20 mmol of sodium nitrite dissolved in a small amount of water was slowly added to the resulting mixture. The temperature of the mixture reached 60 ° C. by the addition of sodium nitrite. It was made to react in this state for 1 hour. Thereafter, an aqueous sodium hydroxide solution was added to adjust the pH of the mixture to 10. After 30 minutes, 20 mL of pure water was added, and diafiltration was performed using a spectrum membrane. Thereby, the self-dispersion in which the content of the pigment is 10.0% and the —C ₆ H ₄ —CONH—CH— (PO (OH) (ONa)) (PO (OH) ₂ ) group is bonded to the particle surface. A dispersion in which the pigment was dispersed was obtained. By substituting sodium ions to ammonium ions by an ion exchange method, the content of the pigment is _{10.0%, -C 6 H 4 -CONH} -CH- (PO (OH) (ONH 4)) on the particle surface ( A pigment dispersion B in which a self-dispersing pigment having a PO (OH) ₂ ) group bonded thereto was obtained was obtained.

(Pigment dispersion C)
A solution prepared by dissolving 5 g of concentrated sulfuric acid in 5.5 g of water was cooled to 5 ° C., and 1.61 g (9.28 mmol) of 4-aminobenzenesulfonic acid was added. Potassium nitrite obtained by dissolving 2.2 g (26 mmol) of potassium nitrite in 9 g of water at 5 ° C. while the solution temperature is kept at 10 ° C. or lower while the container containing the solution is put in an ice bath. The solution was added. After further stirring for 15 minutes, 6 g of carbon black (trade name “Black Pearls 1100”, manufactured by Cabot) was added with stirring. Furthermore, the slurry obtained by stirring for 15 minutes was filtered with a filter paper (trade name “standard filter paper No. 2”, manufactured by Advantech) to obtain particles. The obtained particles were sufficiently cooled with water and then dried in an oven at 110 ° C. Subsequently, water was added to obtain a dispersion liquid in which a self-dispersing pigment having —C ₆ H ₄ —SO ₃ K groups bonded to the particle surface was dispersed, the pigment content being 10.0%. A pigment in which a potassium ion is replaced with an ammonium ion by an ion exchange method, and a self-dispersing pigment having a pigment content of 10.0% and having —C ₆ H ₄ —SO ₃ NH ₄ groups bonded to the particle surface is dispersed. Dispersion C was obtained.

<Synthesis of Compound Represented by General Formula (1)>
(Structure identification method)
The structure of the synthesized compound represented by the general formula (1) was identified by each analysis method shown below.
[1] ¹ H NMR analysis: ¹ H nuclear magnetic resonance spectroscopy (trade name “ECA-400”, manufactured by JEOL Ltd.)
[2] LC / MS analysis: LC / TOF MS (trade name “LC / MSD TOF”, manufactured by Agilent Technologies, ionization method: electrospray ionization method (ESI))
[3] UV / Vis spectroscopic analysis: UV / Vis spectrophotometer (trade name “UV-3600 type spectrophotometer”, manufactured by Shimadzu Corporation)

(Exemplary Compound 1)
3- (4-carboxy-butyrylamino) -2,4,6-trimethylaniline (7.3 g), and 7.4 g of the compound (A) in the above synthesis scheme, 4.1 g of zinc chloride in sulfolane (20 mL) In the presence of, the reaction was carried out by heating at 130 ° C. for 3 hours. The resulting solution was cooled and then added to 50 mL of 2 mol / L hydrochloric acid. The precipitated crystals were collected by filtration, washed with water, and then dried to obtain a dried product. The obtained dried product was suspended in 50 mL of water, and a 2 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 7.0 for dissolution. Then, it crystallized with acetone and the exemplary compound 1 represented by a following formula (1-1) was obtained.

The structure of the obtained exemplary compound 1 was identified by [1] ¹ H NMR analysis, [2] LC / TOF MS analysis, and [3] UV / Vis spectroscopic analysis. The results are shown below.
[1] Results of ¹ H NMR (400 MHz, DMSO-d ₆ , 80 ° C.) (see FIG. 1):
δ [ppm] = 9.20 (s, 2H), 7.99 (d, 1H), 7.51 (t, 1H), 7.45 (t, 1H), 7.09 (d, 1H), 6.96 (s, 2H), 6.74 (s, 1H), 6.71 (s, 1H), 6.61 (bs, 2H), 5.80 (s, 2H), 2.40-1 .50 (m, 30H)
[2] Results of LC / TOF MS analysis (eluent: 0.1% aqueous acetic acid-methanol, ESI):
Retention time 17.4 minutes: Purity = 98.6 area%, m / z = 859.30 [(M-2Na + H) ⁻ ]
[3] Results of UV / Vis spectroscopic analysis (see FIG. 7):
λ _max = 529 nm, ε = 80594 M ⁻¹ cm ⁻¹ (in water, 25 ° C.)

(Exemplary Compound 2)
6 g of the dried product obtained in the synthesis of the “Exemplary Compound 1” was added to 30 g of fuming sulfuric acid under ice cooling, and then stirred at 20 to 25 ° C. for 4 hours to obtain a reaction solution. The obtained reaction solution was poured on 100 g of ice, and the deposited precipitate was collected by filtration and washed with cold water to obtain a precipitate. The obtained precipitate was suspended in 50 mL of water, and a 2 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 7.0 for dissolution. Subsequently, it crystallized with acetone, and the exemplary compound 2 represented by the following formula (1-2) was obtained.

The structure of the obtained exemplary compound 2 was identified by [1] ¹ H NMR analysis, [2] LC / TOF MS analysis, and [3] UV / Vis spectroscopic analysis. The results are shown below.
[1] Results of ¹ H NMR (400 MHz, DMSO-d ₆ , 80 ° C.) (see FIG. 2):
δ [ppm] = 10.00−8.00 (br, 2H), 8.02 (d, 1H), 7.67 (t, 1H), 7.59 (t, 1H), 7.46 (s) 2H), 7.34-7.22 (m, 1H), 7.08 (s, 1H), 7.07 (s, 1H), 5.85 (s, 2H), 2.45-1. 65 (m, 30H)
[2] Results of LC / TOF MS analysis (eluent: 0.1% aqueous acetic acid-methanol, ESI):
Retention time 4.4 minutes: Purity = 0.3 area%, m / z = 509.10 [n = 2, (M-4Na + H) ²⁻ ]
Retention time 8.0 min: Purity = 99.4 area%, m / z = 1019.21 [n = 2, (M−4Na + H) ⁻ ], 509.10 [n = 2, (M−4Na + H) ²⁻ ]
[3] Results of UV / Vis spectroscopic analysis (see FIG. 7):
λ _max = 532.5 nm, ε = 86966 M ⁻¹ cm ⁻¹ (in water, 25 ° C.)

(Exemplary Compound 3)
7.3 g of 3- (3-dimethyl-4-carboxybutyrylamino) -2,4,6-trimethylaniline and 7.4 g of the compound (A) in the above synthesis scheme were placed in 20 mL of sulfolane, and zinc chloride 4 In the presence of 1 g, the reaction was carried out by heating at 130 ° C. for 3 hours. The resulting solution was cooled and then added to 50 mL of 2 mol / L hydrochloric acid. The precipitated crystals were collected by filtration, washed with water, and then dried to obtain a dried product. The obtained dried product was suspended in 50 mL of water, and a 2 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 7.0 for dissolution. Then, it crystallized with acetone, and the exemplary compound 3 represented by the following formula (1-3) was obtained.

The structure of Exemplified Compound 3 obtained was identified by [1] ¹ H NMR analysis, [2] LC / TOF MS analysis, and [3] UV / Vis spectroscopic analysis. The results are shown below.
[1] Results of ¹ H NMR (400 MHz, DMSO-d ₆ , 80 ° C.) (see FIG. 3):
δ [ppm] = 10.93 (s, 2H), 8.00 (d, 1H), 7.54 (t, 1H), 7.47 (t, 1H), 7.12 (d, 1H), 6.98 (s, 2H), 6.82 (s, 1H), 6.80 (s, 1H), 6.68 (brs, 2H), 5.87 (brs, 2H), 2.40 (s 4H), 2.26 (s, 4H), 2.16 (s, 6H), 2.05 (s, 6H), 1.94 (s, 6H), 1.05 (s, 12H)
[2] Results of LC / TOF MS analysis (eluent: 0.1% aqueous acetic acid-methanol, ESI):
Retention time 19.94 min: purity = 99.9 area%, m / z = 915.36 [(M-2Na + H) ⁻ ].
[3] Results of UV / Vis spectroscopic analysis (see FIG. 7):
λ _max = 529.5 nm, ε = 88991 M ⁻¹ cm ⁻¹ (in water, 25 ° C.)

(Exemplary Compound 4)
6 g of the dried product obtained in the synthesis of “Exemplary Compound 3” above was added to 30 g of fuming sulfuric acid under ice cooling, and then stirred at 20 to 25 ° C. for 4 hours to obtain a reaction solution. The obtained reaction solution was poured on 100 g of ice, and the deposited precipitate was collected by filtration and washed with cold water to obtain a precipitate. The obtained precipitate was suspended in 50 mL of water, and a 2 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 7.0 for dissolution. Subsequently, it crystallized with acetone, and the exemplary compound 4 represented by the following formula (1-4) was obtained.

The structure of the obtained exemplary compound 4 was identified by [1] ¹ H NMR analysis, [2] LC / TOF MS analysis, and [3] UV / Vis spectroscopic analysis. The results are shown below.
[1] Results of ¹ H NMR (400 MHz, DMSO-d ₆ , 80 ° C.) (see FIG. 4):
[delta] [ppm] = 11.55-11.00 (m, 2H), 8.05 (d, 1H), 7.65 (t, 1H), 7.62-7.44 (m, 3H), 7 .23 (t, 1H), 7.14-7.00 (m, 2H), 6.15-5.75 (m, 2H), 2.48-1.75 (m, 26H), 1.05 (S, 12H)
[2] Results of LC / TOF MS analysis (eluent: 0.1% aqueous acetic acid-methanol, ESI):
Retention time 11.1 min: Purity = 99.8 area%, m / z = 1075.27 [n = 2, (M−4Na + H) ⁻ ], 537.13 [n = 2, (M−4Na + H) ²⁻ ]
[3] Results of UV / Vis spectroscopic analysis (see FIG. 7):
λ _max = 533 nm, ε = 87480 M ⁻¹ cm ⁻¹ (in water, 25 ° C.)

(Exemplary Compound 5)
7.3 g of 3- (3-cyclopentamethylene-4-carboxy-butyrylamino) -2,4,6-trimethylaniline and 7.4 g of the compound (A) in the above synthesis scheme were placed in 20 mL of sulfolane. And it was made to react by heating at 130 degreeC for 3 hours in presence of 4.1 g of zinc chloride. The resulting solution was cooled and then added to 50 mL of 2 mol / L hydrochloric acid. The precipitated crystals were collected by filtration, washed with water, and then dried to obtain a dried product. The obtained dried product was suspended in 50 mL of water, and a 2 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 7.0 for dissolution. Then, it crystallized with acetone and the exemplary compound 5 represented by a following formula (1-5) was obtained.

The structure of the obtained exemplary compound 5 was identified by [1] ¹ H NMR analysis, [2] LC / TOF MS analysis, and [3] UV / Vis spectroscopic analysis. The results are shown below.
[1] Results of ¹ H NMR (400 MHz, DMSO-d ₆ , 80 ° C.) (see FIG. 5):
δ [ppm] = 11.18 (brs, 2H), 8.02 (d, 2H), 7.56 (t, 1H), 7.49 (t, 1H), 7.13 (d, 1H), 7.00 (s, 1H), 6.87 (s, 1H), 6.85 (s, 1H), 6.74 (brs, 2H), 5.89 (brs, 2H), 2.49 (s) 4H), 2.36 (s, 4H), 2.20-1.80 (m, 18H), 1.45 (s, 16H), 1.39 (s, 4H)
[2] Results of LC / TOF MS analysis (eluent: 0.1% aqueous acetic acid-methanol, ESI):
Retention time 23.1 minutes: purity = 99.9 area%, m / z = 995.42 [(M-2Na + H) ⁻ ].
[3] Results of UV / Vis spectroscopic analysis (see FIG. 7):
λ _max = 530 nm, ε = 81812 M ⁻¹ cm ⁻¹ (in water, 25 ° C.)

(Exemplary Compound 6)
6 g of the dried product obtained in the synthesis of the “Exemplary Compound 5” was added to 30 g of fuming sulfuric acid under ice cooling, and then stirred at 20 to 25 ° C. for 4 hours to obtain a reaction solution. The obtained reaction solution was poured on 100 g of ice, and the deposited precipitate was collected by filtration and washed with cold water to obtain a precipitate. The obtained precipitate was suspended in 50 mL of water, and a 2 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 7.0 for dissolution. Subsequently, it crystallized with acetone, and the exemplary compound 6 represented by the following formula (1-6) was obtained.

The structure of the obtained exemplary compound 6 was identified by [1] ¹ H NMR analysis, [2] LC / TOF MS analysis, and [3] UV / Vis spectroscopic analysis. The results are shown below.
[1] Results of ¹ H NMR (400 MHz, DMSO-d ₆ , 80 ° C.) (see FIG. 6):
δ [ppm] = 12.00-10.00 (m, 2H), 9.52 (br, 1H), 8.05 (d, 2H), 7.70-7.40 (m, 4H), 7 .30-7.15 (m, 1H), 7.05 (s, 2H), 5.91 (brs, 2H), 2.60-1.80 (m, 26H), 1.65-1.20 (M, 20H)
[2] Results of LC / TOF MS analysis (eluent: 0.1% aqueous acetic acid-methanol, ESI):
Retention time 14.1 min: Purity = 99.7 area%, m / z = 1155.34 [n = 2, (M−4Na + H) ⁻ ], 579.16 [n = 2, (M−4Na + H) ²⁻ ]
[3] Results of UV / Vis spectroscopic analysis (see FIG. 7):
λ _max = 533 nm, ε = 90496 M ⁻¹ cm ⁻¹ (in water, 25 ° C.).

<Preparation of ink>
Each component (unit:%) shown in Table 4 was mixed and sufficiently stirred, and then pressure filtered through a polypropylene filter (manufactured by Pole) having a pore size of 2.5 μm to prepare a first ink. Further, each component (unit:%) shown in Table 5 was mixed and sufficiently stirred, and then subjected to pressure filtration with a micro filter (manufactured by Fuji Film) having a pore size of 0.2 μm to prepare a second ink. “Acetylenol E100” in Tables 4 and 5 is a trade name of a nonionic surfactant (manufactured by Kawaken Fine Chemicals). Anthrapyridone compounds 3 and 8 were used as sodium salts. Comparative compound 1 is a compound having a structure represented by the following formula (A).

<Evaluation>
Each ink obtained above was filled in an ink cartridge to obtain an ink set having a combination shown in Table 7. Then, the following items were evaluated. The color of the image was measured using a spectrophotometer (trade name “Spectorolino”, manufactured by Gretag Macbeth) under the conditions of light source: D50 and field of view: 2 °. L ^*, a ^* and b ^*, L ^* in the L ^* a ^* b ^* display system defined by the CIE (Commission Internationale de l'Eclairage), is a ^* and b ^*. Table 7 shows the evaluation results.

(Dark color reproduction range)
The ink cartridge filled with each ink was mounted on an ink jet recording apparatus (trade name “PIXUS MP490”, manufactured by Canon) that ejects ink from the recording head by the action of thermal energy. The first ink was set at the black ink position, and the second ink was set at the magenta ink position. A pattern (secondary color image) including a secondary color solid image was printed on plain paper (trade name “Canon” under the conditions of a temperature of 23 ° C. and a relative humidity of 55% under the recording conditions of Nos. 1 to 9 shown in Table 6. Recorded in “Office Paper” (Canon).

L ^* , a ^*, and b ^* of the solid images in the nine secondary color images recorded under the recording conditions of Nos. 1 to 9 were measured. C ^* = {(a ^* ) ² + (b ^* ) ² } ^1/2 is calculated, the saturation C ^* is calculated, and the horizontal axis represents the saturation C ^* and the vertical axis represents the lightness L ^*. C ^* and L ^* of the image were plotted. Then, the color reproduction range of the dark part was evaluated from the viewpoint of “whether at least one of the solid images satisfies the following condition”. In the present invention, according to the evaluation criteria shown below, “AA”, “A”, and “B” are acceptable levels, and “C” is an unacceptable level.
AA: C ^{* at} L ^* = 40 was 30 or more, and C ^{* at} L ^* = 35 was 20 or more.
A: C ^{* at} L ^* = 40 was 30 or more, and C ^{* at} L ^* = 35 was less than 20.
B: C ^{* at} L ^* = 40 was 10 or more and less than 30, and C ^{* at} L ^* = 35 was 10 or more and less than 20.
C: C ^{* at} L ^* = 40 was less than 10, and C ^{* at} L ^* = 35 was less than 10.

(Bleeding resistance)
The ink cartridge filled with each ink was mounted on an ink jet recording apparatus (trade name “PIXUS MP490”, manufactured by Canon) that ejects ink from the recording head by the action of thermal energy. The first ink was set at the black ink position, and the second ink was set at the magenta ink position. A pattern in which a solid image of 5 cm × 5 cm with the first ink and a solid image of 5 cm × 5 cm with the second ink are arranged in a zigzag pattern under the conditions of a temperature of 23 ° C. and a relative humidity of 55% Recorded in the name "Canon Office Paper", manufactured by Canon. The boundary portion of the recorded solid image was visually confirmed, and bleeding resistance was evaluated according to the following evaluation criteria. In the present invention, according to the evaluation criteria shown below, “A” and “B” are acceptable levels, and “C” is an unacceptable level.
A: No bleeding occurred.
B: Slight bleeding occurred, but the boundary was found.
C: Bleeding occurred so that the boundary was not known.

(Color development of images recorded with the second ink)
The ink cartridge filled with the second ink was mounted on an ink jet recording apparatus (trade name “PIXUS iP8600”, manufactured by Canon Inc.) that discharges ink from the recording head by the action of thermal energy. In this embodiment, a solid image recorded by applying 8 ink droplets of 2.5 pL per droplet to a unit area of 1/600 inch × 1/600 inch is recorded as “recording duty is 100%”. Define. Using this ink jet recording apparatus, 10 types of solid images in which the recording duty is changed from 10% to 100% in 10% increments are recorded on glossy paper in an environment of a temperature of 23 ° C. and a relative humidity of 55%. Got. As the glossy paper, a trade name “Canon Photo Paper / Glossy Gold GL-101” (manufactured by Canon) was used. The obtained recorded matter was dried at a temperature of 23 ° C. and a relative humidity of 55% for 24 hours. A ^* and b ^* of a solid image of each recording duty in the obtained recorded matter were measured. Then, saturation C ^* = {(a ^* ) ² + (b ^* ) ² } ^1/2 was calculated from the values of a ^* and b ^* of the solid image having a recording duty of 100%. Further, a solid image having the largest value of a ^* among the 10 types of solid images was identified, and the hue angle H ° was calculated from the values of a ^* and b ^* of the solid image based on the following formula.
When a ^* ≧ 0 and b ^* ≧ 0 (first quadrant), the hue angle H ° = tan ⁻¹ (b ^* / a ^* )
When a ^* ≦ 0 and b ^* ≧ 0 (second quadrant), the hue angle H ° = 180 + tan ⁻¹ (b ^* / a ^* )
When a ^* ≦ 0 and b ^* ≦ 0 (third quadrant), the hue angle H ° = 180 + tan ⁻¹ (b ^* / a ^* )
When a ^* ≧ 0 and b ^* ≦ 0 (fourth quadrant), the hue angle H ° = 360 + tan ⁻¹ (b ^* / a ^* ).

From the obtained values of C ^* and H °, the color developability of the image recorded with the second ink was evaluated according to the following evaluation criteria. In the present invention, according to the evaluation criteria shown below, “A” is an acceptable level, and “B” and “C” are unacceptable levels.
A: H ° was 340 or more and less than 360, and C ^* was 80 or more.
B: H ° was 340 or more and less than 360, and C ^* was less than 80.
C: H ° was 0 or more and less than 340.

(Light resistance of images recorded with the second ink)
A solid image having a recording duty of 100% was recorded under the same conditions as in the case of the evaluation of “color development of an image recorded with the second ink” to obtain a recorded matter. The obtained recorded matter was dried at a temperature of 23 ° C. and a relative humidity of 55% for 24 hours, and then the optical density of the solid image was measured (referred to as “optical density before test”). Next, the recorded material was put into a xenon test apparatus (trade name “Xenon Weather Meter SX-75”, manufactured by Suga Test Instruments Co., Ltd.), and 240 xenon light was applied to the solid image under the conditions of a bath temperature of 23 ° C., a relative humidity of 50%, and an illuminance of 50 klx. Irradiated for hours. After irradiation with xenon light, the optical density of the solid image of the recorded material was measured (referred to as “optical density after test”). Then, the residual ratio of optical density (%) = (optical density after test / optical density before test) × 100 was calculated, and the light resistance of the image recorded with the second ink was evaluated according to the evaluation criteria shown below. . In the present invention, according to the following evaluation criteria, “A” and “B” are acceptable levels, and “C” and “D” are unacceptable levels.
A: The residual ratio of optical density was 85% or more B: The residual ratio of optical density was 80% or more and less than 85% C: The residual ratio of optical density was 75% or more and less than 80% D: The residual ratio of optical density was less than 75%.

(Moisture resistance of images recorded with the second ink)
A solid image with a recording duty of 100% and a non-recording portion of the same size are arranged in a grid pattern under the same conditions as in the case of the evaluation of “color development of an image recorded with the second ink”. The recorded pattern was recorded to obtain a recorded matter. The obtained recorded matter was dried at a temperature of 23 ° C. and a relative humidity of 55% for 24 hours, and then L ^* , a ^* and b ^* of the solid image were measured (L ₁ ^* , a ₁ ^* and b ₁ ^* and To do). Next, the recorded material was placed in a constant temperature and humidity chamber at a temperature of 30 ° C. and a relative humidity of 90% for 168 hours, and then L ^* , a ^* and b ^* of the solid image were measured (L ₂ ^* , a ₂ ^* and b). ₂ ^* ). Then, the color change (ΔE) = {(L ₁ ^* −L ₂ ^* ) (a ₁ ^* −a ₂ ^* ) ² + (b ₁ ^* −b ₂ ^* ) ² } ^1/2 is calculated and shown below. The moisture resistance of the image recorded with the second ink was evaluated according to the evaluation criteria. In the present invention, “AA”, “A” and “B” are acceptable levels and “C” and “D” are unacceptable levels according to the following evaluation criteria.
AA: ΔE was less than 5.
A: ΔE was 5 or more and less than 8.
B: ΔE was 8 or more and less than 10.
C: ΔE was 10 or more and less than 15.
D: ΔE was 15 or more.

Claims (8)

An ink set having a combination of a first ink and a second ink,
The first ink contains a self-dispersing pigment in which an ionic group is chemically bonded to the pigment particle surface directly or through another atomic group,
The ink set, wherein the second ink contains a compound represented by the following general formula (1).

(In the general formula (1), R ₁ , R ₅ , R ₆ and R ₁₀ each independently represents an alkyl group. R ₃ and R ₈ each independently represent a hydrogen atom, an alkyl group or an alkoxy group. R ₂ , R ₄ , R ₇ and R ₉ each independently represent a hydrogen atom, an ionic group, a group represented by the following general formula (2), or the following: R ₂ , R ₄ , R ₇ and R ₉ each represents a group represented by the following general formula (2), wherein n is 0 to 6 Z represents each independently a sulfonic acid group or a sulfamoyl group. When n is an integer of 1 to 6, Z is bonded to an aromatic ring)

(In the general formula (2), R ₁₁ represents an alkylene group, an arylene group, or an aralkylene group. M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium. * Represents the general formula (1). ) Represents the binding site with the benzene ring in

(In the general formula (3), R ₁₂ represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, or a heterocyclic group. * Represents a benzene ring in the general formula (1). Represents the binding site of In the general formula (1), R ₃ and R ₈ are each independently a hydrogen atom, an unsubstituted alkyl group, an unsubstituted alkoxy group, or an unsubstituted aryloxy group,
In the general formula (2), R ₁₁ is an alkylene group having 3 to 8 carbon atoms, a group having a structure in which a cycloalkylene having 5 to 8 carbon atoms is bonded to a carbon atom constituting a propylene group, or a phenylene group and The ink set according to claim 1, which is an unsubstituted aralkylene group to which a propylene group is bonded.   The ink set according to claim 1 or 2, wherein the number of groups represented by the general formula (2) in the general formula (1) is 2 or more and 4 or less.   The ink set according to any one of claims 1 to 3, wherein, in the general formula (1), n is an integer of 1 to 6, and Z is a sulfonic acid group. 5. The ink set according to claim ₁ , wherein, in the general formula (1), R ₁ , R ₅ , R _6, and R ₁₀ are each independently an alkyl group having 1 to 3 carbon atoms. . 6. The ink set according to claim 1, wherein in the general formula (1), R ₃ and R ₈ are each independently an alkyl group having 1 to 3 carbon atoms. In the general formula (1), R ₁ and R ₆ , R ₂ and R ₇ , R ₃ and R ₈ , R ₄ and R ₉ , and R ₅ and R ₁₀ are the same groups, respectively. The ink set according to any one of 6. An ink jet recording method for recording an image on a recording medium by discharging ink from an ink jet recording head,
An ink jet recording method, wherein the ink is a first ink and a second ink constituting the ink set according to any one of claims 1 to 7.

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