JP2020076048A - Ink composition, inkjet recording ink, and inkjet recording method - Google Patents

Abstract

To provide an ink composition, an inkjet recording ink and an inkjet recording method that are capable of forming an image excellent in the gray-to-black hue, print density, moisture resistance, light resistance and ozone resistance.SOLUTION: An ink composition contains a colorant represented by the general formula (I) in the figure, water, a specific compound, and a specific toning agent. Also provided are an inkjet recording ink including the ink composition, and an inkjet recording method based on the ink composition.SELECTED DRAWING: None

Description

  The present invention relates to an ink composition, an inkjet recording ink, and an inkjet recording method.

The inkjet recording method is rapidly spreading and further developing because of low material cost, high-speed recording, low noise during recording, and easy color recording.
As an ink composition used in the inkjet recording method, compositions containing various coloring agents (colorants) have been proposed. In addition, compounds that are added to the ink composition have also been investigated in order to improve various performances.
For example, Patent Document 1 discloses that a cyan ink in which the bronze gloss of an inkjet print is suppressed by using a phthalocyanine dye and a specific planar compound in combination.

JP, 2005-105261, A

  However, in recent years, further improvement in performance has been demanded in the field of ink, and there has been a problem that the color tone of an image from gray to black changes due to natural aging (especially change in humidity). .. Further, high performance is also required for printing density, light resistance, and ozone resistance.

  An object of the present invention is to provide an ink composition capable of forming an image having excellent hue from gray to black and printing density, and having excellent moisture resistance, light resistance, and ozone resistance, an inkjet recording ink, and an inkjet. It is to provide a recording method.

  The present inventors have found that the above object can be achieved by the following configurations.

<1>
An ink composition containing a colorant represented by the following general formula (I), water, a compound represented by the following general formula (II), and a toning agent represented by the following general formula (III).

In formula (I), R ₁ , R ₂ , and R ₄ each independently represent a hydrogen atom or a substituent. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. m represents an integer of 1 to 6. G represents a nitrogen atom or -C (-W) =. W represents an electron-withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃ represents an aromatic group which may have a substituent or a heterocyclic group which may have a substituent.

In the general formula (II), Ar ₂₀ represents a benzene ring or a naphthalene ring. R _{21 to} R ₂₈ each independently represent a hydrogen atom or a substituent. R ₂₁ and R ₂₂ may combine to form a ring. R ₂₃ and R ₂₄ may combine to form a ring. R ₂₅ and R ₂₆ may combine to form a ring. R ₂₇ and R ₂₈ may combine to form a ring. R ₂₉ represents a substituent. When Ar ₂₀ represents a benzene ring, k represents an integer of 0-4. When Ar ₂₀ represents a naphthalene ring, k represents an integer of 0 to 6. If R ₂₉ there are a plurality, may be with or different plural R ₂₉ are the same respectively. If R ₂₉ there are a plurality, may form a ring with a plurality of R ₂₉ is bonded. However, the compound represented by the general formula (II) has at least one hydrophilic group.

In general formula (III), M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. Z represents a divalent linking group.
<2>
The ink composition according to <1>, which contains a toning agent represented by any one of the following general formulas (M1) to (M8).

In formula (M1), R ₄₁ and R ₄₂ each independently represent a substituent. p1 and p2 each independently represent an integer of 0 to 5. When a plurality of R ₄₁ and R ₄₂ are present, they may be the same or different. At least two R _41's may combine with each other to form a ring. At least two R _42's may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M2), Ar ₁ and Ar ₂ each independently represent an aromatic group which may have a substituent or a heterocyclic group which may have a substituent. L ₁ represents a divalent linking group. Z ₁ and Z ₂ each independently represent —OM ′ or a halogen atom. M and M ′ each independently represent a hydrogen atom or a counter cation. The plurality of M may be the same or different. When there are a plurality of M ′, the plurality of M ′ may be the same or different.

In formula (M3), R ₄₃ and R ₄₄ each independently represent a substituent. p3 and p4 each independently represent an integer of 0 to 5. When a plurality of R ₄₃ and R ₄₄ are present, they may be the same or different. At least two R ₄₃ may combine with each other to form a ring. At least two R ₄₄ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M4), R ₄₅ , R _46, and R ₄₇ each independently represent a hydrogen atom or a substituent. R ₄₆ and R ₄₇ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M5), R _{51 to} R ₅₁₂ each independently represent a hydrogen atom or a substituent. R ₅₁ and R ₅₂ may combine with each other to form a ring. R ₅₃ and R ₅₄ may combine with each other to form a ring. At least two of R _{58 to} R ₅₁₂ may combine with each other to form a ring. The toning agent represented by formula (M5) has at least one —SO ₃ M. M represents a hydrogen atom or a counter cation.

In formula (M6), R _{61 to} R ₆₆ each independently represent a hydrogen atom or a substituent. At least two of R _{63 to} R ₆₆ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation.

In formula (M7), R _{71 to} R ₇₄ each independently represent a hydrogen atom or a substituent. L ₂ represents a divalent linking group. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M8), R _{81 to} R ₈₁₂ each independently represent a hydrogen atom or a substituent. At least two of R _{81 to} R ₈₅ may combine with each other to form a ring. At least two of R _{86 to} R ₈₁₀ may combine with each other to form a ring.
<3>
The ink composition according to <1> or <2>, wherein the colorant represented by the general formula (I) is a colorant represented by the following general formula (IV).

In general formula (IV), M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. n represents 1 or 2. G represents a nitrogen atom or -C (-W) =. W and W ₁ each independently represent an electron withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃₀ represents an optionally substituted aromatic group. R ₄ represents a hydrogen atom or a substituent.
<4>
The colorant represented by the general formula (I) contains at least one of the colorant represented by the following general formula (V) and the colorant represented by the following general formula (VI) <1> ~ The ink composition according to any one of <3>.

In formulas (V) and (VI), R ₃₀ represents an aromatic group which may be substituted. R _4S represents _{-SO 3 M, -NO 2, -NHCOR} 5S, -NHSO 2 R 5S, or -NHCONHR _5S. R _5S represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.
<5>
The ink composition according to any one of <1> to <4>, in which the compound represented by the general formula (II) has at least one ionic hydrophilic group.
<6>
The ink composition according to any one of <1> to <5>, in which at least one of R _{21 to} R _{29 in} the general formula (II) has an ionic hydrophilic group.
<7>
The content of the compound represented by the general formula (II) is 0.5 to 1.5 mass% based on the total mass of the ink composition, and <1> to <6 for gray ink. > The ink composition according to any one of items>.
<8>
The content of the compound represented by the general formula (II) is 3.0 to 5.0 mass% based on the total mass of the ink composition, and is for black ink, <1> to <6. > The ink composition according to any one of items>.
<9>
In any one of <1> to <8>, which contains a chelating agent, and the content of the chelating agent is 0.001 to 0.3 mass% based on the total mass of the ink composition. The ink composition described.
<10>
An inkjet recording ink containing the ink composition according to any one of <1> to <9>.
<11>
An inkjet recording method using the inkjet recording ink according to <10>.

  ADVANTAGE OF THE INVENTION According to this invention, the ink composition which can form the image excellent in the hue from gray to black, and the printing density, and also excellent in moisture resistance, light resistance, and ozone resistance, an inkjet recording ink, and inkjet. A recording method can be provided.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

<Ink composition>
The ink composition of the present invention comprises a colorant represented by the following general formula (I), water, a compound represented by the following general formula (II), and a toning agent represented by the following general formula (III). It is an ink composition containing.

In formula (I), R ₁ , R ₂ , and R ₄ each independently represent a hydrogen atom or a substituent. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. m represents an integer of 1 to 6. G represents a nitrogen atom or -C (-W) =. W represents an electron-withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃ represents an aromatic group which may have a substituent or a heterocyclic group which may have a substituent.

In the general formula (II), Ar ₂₀ represents a benzene ring or a naphthalene ring. R _{21 to} R ₂₈ each independently represent a hydrogen atom or a substituent. R ₂₁ and R ₂₂ may combine to form a ring. R ₂₃ and R ₂₄ may combine to form a ring. R ₂₅ and R ₂₆ may combine to form a ring. R ₂₇ and R ₂₈ may combine to form a ring. R ₂₉ represents a substituent. When Ar ₂₀ represents a benzene ring, k represents an integer of 0-4. When Ar ₂₀ represents a naphthalene ring, k represents an integer of 0 to 6. If R ₂₉ there are a plurality, may be with or different plural R ₂₉ are the same respectively. If R ₂₉ there are a plurality, may form a ring with a plurality of R ₂₉ is bonded. However, the compound represented by the general formula (II) has at least one hydrophilic group.

  In general formula (III), M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. Z represents a divalent linking group.

The reason why the ink composition of the present invention can form an image excellent in gray to black color tone and excellent in moisture resistance is not completely clear, but the present inventors have the following. Is estimated.
An ink composition containing a colorant represented by the general formula (I) and a toning agent represented by the general formula (III) is used to form an image excellent in gray to black color tone by an inkjet method. can do. In the image just after being formed, it is considered that the colorant represented by the general formula (I) forms a relatively stable association state. On the other hand, when the humidity of the surrounding environment becomes high, the highly water-soluble coloring agent represented by the general formula (I) proceeds to a more stable association state by using water as a driving force (the H-aggregate of the dye). It is presumed that the color tone of the image changes (short wavelength shift of the color tone derived from the H-aggregate) as a result.
Therefore, in the present invention, by adding the compound represented by the general formula (II), which is a highly planar compound, the coloring represented by the general formula (I) in the image immediately after formed by the inkjet method is added. The relatively stable association state of the agent is stabilized by the intermolecular interaction between the colorant represented by the general formula (I) and the compound represented by the general formula (II), or immediately after the formation of the image by the general formula. A more stable association state can be formed by intermolecular interaction between the colorant represented by (I) and the compound represented by the general formula (II). As a result, it is possible to suppress the change in the color tone of the image without causing the change in the association state of the colorant represented by the general formula (I) due to the change in the surrounding environment (humidity, light, active gas), It is considered that the image fastness (moisture resistance, light resistance, ozone resistance) was improved.

(Colorant represented by the general formula (I))
The colorant represented by formula (I) will be described.

In formula (I), R ₁ , R ₂ , and R ₄ each independently represent a hydrogen atom or a substituent. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. m represents an integer of 1 to 6. G represents a nitrogen atom or -C (-W) =. W represents an electron-withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃ represents an aromatic group which may have a substituent or a heterocyclic group which may have a substituent.

When R ₁ , R ₂ and R ₄ each represent a substituent, the substituent is not particularly limited, and examples thereof include a substituent selected from the following substituent group A.

<Substituent group A>
Substituent group A includes the following substituents.
Halogen atom, aliphatic group, aromatic group, heterocyclic group, cyano group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, acyl group, hydroxy group, alkoxy group, aryloxy group, hetero Ring oxy group, silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, acylamino group, ureido group, sulfamoylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group , Alkylsulfonylamino group, arylsulfonylamino group, heterocyclic sulfonylamino group, nitro group, alkylthio group, arylthio group, heterocyclic thio group, alkylsulfonyl group, arylsulfonyl group, heterocyclic sulfonyl group, alkylsulfinyl group, arylsulfinyl A group, a heterocyclic sulfinyl group, a sulfamoyl group, an azo group, an ionic hydrophilic group, and a substituent formed by combining these groups.

  Hereinafter, each substituent of the substituent group A will be described in detail.

  Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.

  Examples of the aliphatic group include an alkyl group, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an alkynyl group, a substituted alkynyl group, an aralkyl group, and a substituted aralkyl group. The aliphatic group may have a branch and may form a ring. The aliphatic group preferably has 1 to 20 carbon atoms, and more preferably 1 to 16 carbon atoms. The aryl group portion of the aralkyl group and the substituted aralkyl group is preferably a phenyl group or a naphthyl group, and a phenyl group is particularly preferable. Examples of the aliphatic group include methyl group, ethyl group, butyl group, isopropyl group, t-butyl group, hydroxyethyl group, methoxyethyl group, cyanoethyl group, trifluoromethyl group, 3-sulfopropyl group, 4-sulfobutyl group. Group, cyclohexyl group, benzyl group, 2-phenethyl group, vinyl group and allyl group.

  Examples of the aromatic group include an aryl group and a substituted aryl group. The aryl group is preferably a phenyl group or a naphthyl group. The aromatic group has preferably 6 to 20 carbon atoms, and more preferably 6 to 16 carbon atoms. Examples of the aromatic group include a phenyl group, a p-tolyl group, a p-methoxyphenyl group, an o-chlorophenyl group and an m- (3-sulfopropylamino) phenyl group.

  The heterocyclic group includes a heterocyclic group having a substituent and an unsubstituted heterocyclic group. The heterocycle may be condensed with an aliphatic ring, an aromatic ring or another heterocycle. The heterocyclic group is preferably a 5- or 6-membered heterocyclic group, and the heteroatoms of the heterocycle include N, O, and S. Examples of the substituent include an aliphatic group, a halogen atom, an alkyl group and an arylsulfonyl group, an acyl group, an acylamino group, a sulfamoyl group, a carbamoyl group and an ionic hydrophilic group. Examples of the heterocyclic group include 2-pyridyl group, 2-thienyl group, 2-thiazolyl group, 2-benzothiazolyl group, 2-benzoxazolyl group and 2-furyl group.

  The carbamoyl group includes a carbamoyl group having a substituent and an unsubstituted carbamoyl group. Examples of the above substituent include an alkyl group. Examples of the carbamoyl group include a methylcarbamoyl group and a dimethylcarbamoyl group.

  The alkoxycarbonyl group includes an alkoxycarbonyl group having a substituent and an unsubstituted alkoxycarbonyl group. As the alkoxycarbonyl group, an alkoxycarbonyl group having 2 to 20 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

  The aryloxycarbonyl group includes an aryloxycarbonyl group having a substituent and an unsubstituted aryloxycarbonyl group. As the aryloxycarbonyl group, an aryloxycarbonyl group having 7 to 20 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the aryloxycarbonyl group include a phenoxycarbonyl group.

  The heterocyclic oxycarbonyl group includes a heterocyclic oxycarbonyl group having a substituent and an unsubstituted heterocyclic oxycarbonyl group. The heterocyclic oxycarbonyl group is preferably a heterocyclic oxycarbonyl group having 2 to 20 carbon atoms. Examples of the substituent include an ionic hydrophilic group. Examples of the heterocyclic oxycarbonyl group include a 2-pyridyloxycarbonyl group.

  The acyl group includes an acyl group having a substituent and an unsubstituted acyl group. As the acyl group, an acyl group having 1 to 20 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the acyl group include an acetyl group and a benzoyl group.

  The alkoxy group includes an alkoxy group having a substituent and an unsubstituted alkoxy group. As the alkoxy group, an alkoxy group having 1 to 20 carbon atoms is preferable. Examples of the substituent include an alkoxy group, a hydroxyl group, and an ionic hydrophilic group. Examples of the alkoxy group include a methoxy group, an ethoxy group, an isopropoxy group, a methoxyethoxy group, a hydroxyethoxy group and a 3-carboxypropoxy group.

  The aryloxy group includes an aryloxy group having a substituent and an unsubstituted aryloxy group. As the aryloxy group, an aryloxy group having 6 to 20 carbon atoms is preferable. Examples of the substituent include an alkoxy group and an ionic hydrophilic group. Examples of the aryloxy group include a phenoxy group, a p-methoxyphenoxy group and an o-methoxyphenoxy group.

  The heterocyclic oxy group includes a heterocyclic oxy group having a substituent and an unsubstituted heterocyclic oxy group. As the heterocyclic oxy group, a heterocyclic oxy group having 2 to 20 carbon atoms is preferable. Examples of the substituent include an alkyl group, an alkoxy group, and an ionic hydrophilic group. Examples of the heterocyclic oxy group include 3-pyridyloxy group and 3-thienyloxy group.

  The silyloxy group is preferably a silyloxy group substituted with an aliphatic group or aromatic group having 1 to 20 carbon atoms. Examples of the silyloxy group include trimethylsilyloxy and diphenylmethylsilyloxy.

  The acyloxy group includes an acyloxy group having a substituent and an unsubstituted acyloxy group. As the acyloxy group, an acyloxy group having 1 to 20 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the acyloxy group include an acetoxy group and a benzoyloxy group.

  The carbamoyloxy group includes a carbamoyloxy group having a substituent and an unsubstituted carbamoyloxy group. Examples of the substituent include an alkyl group. Examples of the carbamoyloxy group include an N-methylcarbamoyloxy group.

  The alkoxycarbonyloxy group includes an alkoxycarbonyloxy group having a substituent and an unsubstituted alkoxycarbonyloxy group. As the alkoxycarbonyloxy group, an alkoxycarbonyloxy group having 2 to 20 carbon atoms is preferable. Examples of the alkoxycarbonyloxy group include a methoxycarbonyloxy group and an isopropoxycarbonyloxy group.

  The aryloxycarbonyloxy group includes an aryloxycarbonyloxy group having a substituent and an unsubstituted aryloxycarbonyloxy group. The aryloxycarbonyloxy group is preferably an aryloxycarbonyloxy group having 7 to 20 carbon atoms. Examples of the aryloxycarbonyloxy group include a phenoxycarbonyloxy group.

  The amino group includes an amino group substituted with an alkyl group, an aryl group or a heterocyclic group, and the alkyl group, the aryl group and the heterocyclic group may further have a substituent. As the alkylamino group, an alkylamino group having 1 to 20 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the alkylamino group include a methylamino group and a diethylamino group. The arylamino group includes an arylamino group having a substituent and an unsubstituted arylamino group, and further an anilino group. The arylamino group is preferably an arylamino group having 6 to 20 carbon atoms. Examples of the substituent include a halogen atom and an ionic hydrophilic group. Examples of the arylamino group include a phenylamino group and a 2-chlorophenylamino group. The heterocyclic amino group includes a heterocyclic amino group having a substituent and an unsubstituted heterocyclic amino group. The heterocyclic amino group is preferably a heterocyclic amino group having 2 to 20 carbon atoms. Examples of the substituent include an alkyl group, a halogen atom, and an ionic hydrophilic group.

  The acylamino group includes an acylamino group having a substituent and an unsubstituted acylamino group. The acylamino group is preferably an acylamino group having 2 to 20 carbon atoms. Examples of the substituent include an ionic hydrophilic group. Examples of the acylamino group include an acetylamino group, a propionylamino group, a benzoylamino group, an N-phenylacetylamino group and a 3,5-disulfobenzoylamino group.

  The ureido group includes a ureido group having a substituent and an unsubstituted ureido group. The ureido group is preferably an ureido group having 1 to 20 carbon atoms. Examples of the substituent include an alkyl group and an aryl group. Examples of the ureido group include a 3-methylureido group, a 3,3-dimethylureido group and a 3-phenylureido group.

  The sulfamoylamino group includes a sulfamoylamino group having a substituent and an unsubstituted sulfamoylamino group. Examples of the substituent include an alkyl group. Examples of the sulfamoylamino group include N, N-dipropylsulfamoylamino group.

  The alkoxycarbonylamino group includes an alkoxycarbonylamino group having a substituent and an unsubstituted alkoxycarbonylamino group. As the alkoxycarbonylamino group, an alkoxycarbonylamino group having 2 to 20 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the alkoxycarbonylamino group include an ethoxycarbonylamino group.

  The aryloxycarbonylamino group includes an aryloxycarbonylamino group having a substituent and an unsubstituted aryloxycarbonylamino group. The aryloxycarbonylamino group is preferably an aryloxycarbonylamino group having 7 to 20 carbon atoms. Examples of the substituent include an ionic hydrophilic group. Examples of the aryloxycarbonylamino group include a phenoxycarbonylamino group.

  The alkyl- and aryl-sulfonylamino group includes an alkyl- and aryl-sulfonylamino group having a substituent and an unsubstituted alkyl- and aryl-sulfonylamino group. The sulfonylamino group is preferably a sulfonylamino group having 1 to 20 carbon atoms. Examples of the substituent include an ionic hydrophilic group. Examples of these sulfonylamino groups include a methylsulfonylamino group, an N-phenyl-methylsulfonylamino group, a phenylsulfonylamino group, and a 3-carboxyphenylsulfonylamino group.

  The heterocyclic sulfonylamino group includes a heterocyclic sulfonylamino group having a substituent and an unsubstituted heterocyclic sulfonylamino group. As the heterocyclic sulfonylamino group, a heterocyclic sulfonylamino group having 1 to 12 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the heterocyclic sulfonylamino group include a 2-thiophene sulfonylamino group and a 3-pyridinesulfonylamino group.

  The alkyl, aryl and heterocyclic thio groups include an alkyl, aryl and heterocyclic thio group having a substituent and an unsubstituted alkyl, aryl and heterocyclic thio group. The alkyl, aryl and heterocyclic thio groups preferably have 1 to 20 carbon atoms. Examples of the substituent include an ionic hydrophilic group. Examples of the alkyl, aryl and heterocyclic thio groups include a methylthio group, a phenylthio group and a 2-pyridylthio group.

  The alkyl and aryl sulfonyl groups include an alkyl and aryl sulfonyl group having a substituent and an unsubstituted alkyl and aryl sulfonyl group. Examples of the alkyl and aryl sulfonyl groups may include a methyl sulfonyl group and a phenyl sulfonyl group, respectively.

  The heterocyclic sulfonyl group includes a heterocyclic sulfonyl group having a substituent and an unsubstituted heterocyclic sulfonyl group. The heterocyclic sulfonyl group is preferably a heterocyclic sulfonyl group having 1 to 20 carbon atoms. Examples of the substituent include an ionic hydrophilic group. Examples of the heterocyclic sulfonyl group include a 2-thiophene sulfonyl group and a 3-pyridine sulfonyl group.

  The alkyl and aryl sulfinyl groups include an alkyl and aryl sulfinyl group having a substituent and an unsubstituted alkyl and aryl sulfinyl group. Examples of the alkyl and arylsulfinyl groups include a methylsulfinyl group and a phenylsulfinyl group, respectively.

  The heterocyclic sulfinyl group includes a heterocyclic sulfinyl group having a substituent and an unsubstituted heterocyclic sulfinyl group. As the heterocyclic sulfinyl group, a heterocyclic sulfinyl group having 1 to 20 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the heterocyclic sulfinyl group include 4-pyridinesulfinyl group.

  The sulfamoyl group includes a sulfamoyl group having a substituent and an unsubstituted sulfamoyl group. Examples of the substituent include an alkyl group. Examples of the sulfamoyl group include a dimethylsulfamoyl group and a di- (2-hydroxyethyl) sulfamoyl group.

  Examples of the azo group include a phenylazo group, a 4-methoxyphenylazo group, a 4-pivaloylaminophenylazo group, a 2-hydroxy-4-propanoylphenylazo group, a heterocyclic azo group having a substituent, and an unsubstituted group. Examples thereof include a heterocyclic azo group.

Examples of the ionic hydrophilic group, a sulfo group _(-SO 3 M), a carboxy group (-COOM), phosphate groups (-PO _{(OM) 2)} and a quaternary ammonium group, an acylsulfamoyl group (- ^{_{SO 2 N - M + COR)}} , a sulfonylcarbamoyl group _{^{(-CON - M + SO 2 -R}} ), sulfonylsulfamoyl groups ^{_{(-SO 2 N - M + SO}} 2 -R) , and the like are included. The above M represents a hydrogen atom or a counter cation. The R includes a monovalent substituent (for example, an alkyl group, an aryl group) and the like. Among them, a sulfo group _(-SO 3 M), a carboxy group (-COOM), and phosphoric acid group (-PO _{(OM) 2)} are preferred, in particular a sulfo group _(-SO 3 M), and a carboxy group (-COOM) Is preferred.
As described above, the ionic hydrophilic group may be in a salt state, and examples of the counter cation forming the salt include ammonium ion, alkali metal ion (eg, lithium ion, sodium ion, potassium ion) and organic. Cations (eg, tetramethylammonium ion, tetramethylguanidinium ion, tetramethylphosphonium ion) are included.
M is preferably a hydrogen atom, an ammonium ion or an alkali metal ion, more preferably an alkali metal ion, further preferably a lithium ion, a sodium ion or a potassium ion, and a lithium ion or a sodium ion. Is particularly preferable, and lithium ion is most preferable.

In the general formula (I), R ₁ represents a hydrogen atom, an alkyl group having a total carbon number of 1 to 8, an aryl group having a total carbon number of 6 to 12, a halogen atom, a hydroxy group, an amino group, or a total carbon number of 1 to 6. It is preferably an alkylamino group, an arylamino group having a total carbon number of 1 to 12, or a heterocyclic amino group having a total carbon number of 1 to 11, and a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, i-propyl. Group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, phenyl group, hydroxy group, or amino group, more preferably a hydrogen atom, a methyl group, or an ethyl group. Is more preferable, and a methyl group is particularly preferable.

In the general formula (I), R ₂ is preferably an electron-withdrawing group having a Hammett's substituent constant σp value of 0.2 or more, and an σp value of 0.30 or more. The electron withdrawing group having a σp value of 0.45 or more is more preferable, and the electron withdrawing group having a σp value of 0.60 or more is particularly preferable. R ₂ preferably has a σp value not exceeding 1.0.
The Hammett's substituent constant σp value used in the present specification will be described.
Hammett's rule is used to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives in 1935 L.A. P. The rule of thumb proposed by Hammett, which is widely accepted today. Substituent constants determined by Hammett's law include σp values and σm values, and these values can be found in many general textbooks. A. Dean ed., “Lange's Handbook of Chemistry” 12th edition, 1979 (McGraw-Hill) and “Chemistry” extra number, 122, 96-103 pages, 1979 (Nankodo). In the present invention, each substituent is limited or explained by Hammett's substituent constant σp, but in the sense that it is limited only to a substituent having a value known in the literature, which can be found in the above-mentioned book. Needless to say, even if the value is unknown in the literature, it also includes a substituent that may be included in the range when measured based on Hammett's rule. Although the compound according to the present invention is not a benzene derivative, the σp value is used as a measure of the electronic effect of a substituent regardless of the substitution position. In the present invention, the σp value will be used in this meaning from now on.
More specifically, R ₂ is an acyl group having 2 to 20 carbon atoms, an alkyloxycarbonyl group having 2 to 20 carbon atoms, a nitro group, a cyano group, an alkylsulfonyl group having 1 to 20 carbon atoms, or a total carbon number. It is preferably an arylsulfonyl group having 6 to 20 carbon atoms, a carbamoyl group having 1 to 20 carbon atoms in total, or a halogenated alkyl group having 1 to 20 carbon atoms in total. R ₂ is more preferably a cyano group, an alkyloxycarbonyl group having a total carbon number of 2 to 10, an alkylsulfonyl group having a total carbon number of 1 to 20 or an arylsulfonyl group having a total carbon number of 6 to 20, and a cyano group. , A methyloxycarbonyl group, a methylsulfonyl group, or a phenylsulfonyl group is particularly preferable, and a cyano group is most preferable.

In the general formula (I), R ₄ represents a hydrogen atom, a halogen atom, a hydroxy group, a nitro group, an amino group, an alkylamino group, an arylamino group, a heterocyclic amino group, an alkylcarbonylamino group, an alkylsulfonylamino group, an aryl. A sulfonylamino group, a heterocyclic sulfonylamino group, an azo group (for example, -N = N-aryl, -N = N-heterocycle), or an ionic hydrophilic group is preferable, and a hydrogen atom, a halogen atom, and a hydroxy group are used. Group, nitro group, amino group, alkylamino group having 1 to 8 carbon atoms, arylamino group having 6 to 12 carbon atoms, heterocyclic amino group having 1 to 10 carbon atoms, alkyl having 1 to 7 carbon atoms Carbonylamino group, alkylsulfonylamino group having 1 to 6 carbon atoms, arylsulfonylamino group having 6 to 12 carbon atoms, heterocyclic sulfonylamino group having 1 to 7 carbon atoms, sulfo group (and a salt thereof), or A carboxy group (and a salt thereof) is more preferable, and a hydrogen atom, a nitro group, an alkylcarbonylamino group having a total carbon number of 1 to 5, or a sulfo group (and a salt thereof) is particularly preferable.

Examples of the aromatic group or heterocyclic group represented by R ₃ in the above general formula (I) include the aromatic groups and heterocyclic groups listed as the above-mentioned substituent group A.
R ₃ preferably represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and an aromatic which may have a substituent. More preferably, it represents a group hydrocarbon group.
More specifically, R ₃ is a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted heterocyclic group (eg, pyrrole ring group, thiophene ring group, imidazole ring group, thiazole Ring group, benzothiazole ring group, pyridine ring group or pyridazine ring group), preferably a substituted phenyl group (particularly para-substituted phenyl group), substituted or unsubstituted β-naphthyl group, 2-pyridine ring group , 3-pyridine ring group, 4-pyridine ring group, or thiazole ring group are more preferable, and unsubstituted β-naphthyl group is most preferable.

In the general formula (I), G represents a nitrogen atom or = CW-, and W represents an electron-withdrawing group having a Hammett's substituent constant σp value of 0.20 or more. W is preferably an electron withdrawing group having a σp value of 0.30 or more, more preferably an electron withdrawing group having a σp value of 0.45 or more, and a σp value of 0.60 or more. An electron-withdrawing group is particularly preferable. It is desirable that the σp value of W does not exceed 1.0.
G represents a nitrogen atom or = CW-, wherein W is an acyl group having 2 to 20 carbon atoms, an alkyloxycarbonyl group having 2 to 20 carbon atoms, a nitro group, a cyano group, an alkylsulfonyl group having 1 to 20 carbon atoms. It is preferably an arylsulfonyl group having 6 to 20 carbon atoms, a carbamoyl group having 1 to 20 carbon atoms, or a halogenated alkyl group having 1 to 20 carbon atoms.
G represents a nitrogen atom or = CW-, and W is more preferably a cyano group, an alkylsulfonyl group having 1 to 20 carbon atoms, or an arylsulfonyl group having 6 to 20 carbon atoms.
G represents a nitrogen atom or = CW-, and it is more preferable that W is a cyano group, a methylsulfonyl group, or a phenylsulfonyl group.
G represents a nitrogen atom or = CW-, and it is particularly preferable that W is a cyano group from the viewpoint of the hue, oxidation potential and association property (image fastness) of the azo dye.

In the above general formula (I), M represents a hydrogen atom or a counter cation. The counter cation is not particularly limited, and examples thereof include alkali metal ions, ammonium ions, and organic cations (tetramethylammonium, guanidinium, pyridinium, etc.).
M is preferably a hydrogen atom, an ammonium ion or an alkali metal ion, more preferably an alkali metal ion, further preferably a lithium ion, a sodium ion or a potassium ion, and a lithium ion or a sodium ion. Is particularly preferable, and lithium ion is most preferable. Particularly, a lithium salt of a sulfo group (—SO ₃ Li) is preferable because it enhances the solubility of the dye and improves the ink stability.
In addition, M may be a divalent counter cation. When M is a divalent counter cation, one M may serve as two —SO ₃ ^— counter cations.
From the viewpoint of water solubility, M is preferably a monovalent counter cation.
When M represents a lithium ion, it is not necessary for all M to be a lithium ion, but it is preferable that the counter cation having the substantially highest abundance ratio is a lithium ion. Under such abundance ratio conditions, hydrogen atom as M, alkali metal ion (for example, sodium ion, potassium ion), alkaline earth metal ion (for example, magnesium ion, calcium ion, etc.), quaternary ammonium ion, 4 It can include a primary phosphonium ion, a sulfonium ion, and the like. The amount of lithium ions is preferably 50% or more, more preferably 60% or more, still more preferably 80% or more, particularly preferably 90% or more, with respect to the total amount of M, and the upper limit. Is preferably 100%.

  In the above general formula (I), m represents an integer of 1 to 6, preferably an integer of 2 to 4, and preferably 2 or 3 for imparting the association property of the azo dye molecule and the water solubility of the azo dye. From the viewpoint of compatibility, it is particularly preferable, and 2 is the most preferable.

In the general formula (I), examples of the substituent in the case where each of the substituents represented by R ₁ , R ₂ , R ₃ , R ₄ and W can further have a substituent include the above-mentioned substituent group. A substituent selected from A can be mentioned.

The colorant represented by the general formula (I) is a colorant represented by the following general formula (I-2) as an embodiment in which the aromatic group or heterocyclic group represented by R ₃ has a substituent. It may be.

In formula (I-2), R ₁ , R ₂ , and R ₄ each independently represent a hydrogen atom or a substituent. M represents a hydrogen atom or a counter cation. m represents an integer of 1 to 6. G represents a nitrogen atom or -C (-W) =. W represents an electron-withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃ represents an aromatic group which may have a substituent or a heterocyclic group which may have a substituent. The plurality of R ₁ , R ₂ , R ₄ , M, m, G, and R ₃ may be the same or different. Z ₁₀ represents a divalent linking group.

In the general formula _{(I-2), R 1} , R 2, R 4, M, m, G, and _{R 3, R} 1, respectively in formula _{(I), R 2, R} 4, M, m, It has the same meaning as G and R ₃ and the preferred range is also the same.

  The colorant represented by the general formula (I) is preferably a colorant represented by the following general formula (IV).

In general formula (IV), M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. n represents 1 or 2. G represents a nitrogen atom or -C (-W) =. W and W ₁ each independently represent an electron withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃₀ represents an optionally substituted aromatic group. R ₄ represents a hydrogen atom or a substituent.

  In the above general formula (IV), n represents 1 or 2. It is particularly preferable that n represents 2 from the viewpoint of providing both the association property of the azo dye molecule and the water solubility of the azo dye.

In the general formula (IV), the preferable range of W ₁ is the same as R ₂ in the general formula (I).

  In the general formula (IV), M has the same meaning as M in the general formula (I), and the preferred range is also the same.

  In the general formula (IV), G has the same meaning as G in the general formula (I), and the preferred range is also the same.

In the general formula (IV), the preferable range of R ₃₀ is that of the optionally substituted aromatic group (which may have a substituent) of R _{3 in} the general formula (I). It is the same as the preferred range.

In the general formula (IV), R ₄ has the same meaning as R ₄ in the general formula (I), and the preferred range is also the same.

  The colorant represented by the general formula (IV) is preferably a colorant represented by the following general formula (IV-2).

In general formula (IV-2), M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. n represents 1 or 2. G represents a nitrogen atom or -C (-W) =. W and W ₁ each independently represent an electron withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃₀ represents an optionally substituted aromatic group. R ₄ represents a hydrogen atom or a substituent.

In general formula (IV-2), M, n, G, W, W ₁ , R ₃₀ and R ₄ are each M, n, G, W, W ₁ , R ₃₀ in general formula (IV). And R ₄ have the same meanings, and preferred ranges are also the same.

  The colorant represented by the general formula (I), the colorant represented by the general formula (IV), and the colorant represented by the general formula (IV-2) are represented by the following general formula (V). It is preferable to include at least one of the colorant represented and the colorant represented by the following general formula (VI).

In formulas (V) and (VI), R ₃₀ represents an aromatic group which may be substituted. R _4S represents _{-SO 3 M, -NO 2, -NHCOR} 5S, -NHSO 2 R 5S, or -NHCONHR _5S. R _5S represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

  In the general formulas (V) and (VI), M has the same meaning as M in the general formula (IV), and the preferred range is also the same.

In the general formulas (V) and (VI), R ₃₀ has the same meaning as R ₃₀ in the general formula (IV), and the preferred range is also the same.

In the general formulas (V) and (VI), R _4S is —SO ₃ M (sulfo group or a salt thereof), —NO ₂ (nitro group), —NHCOR _5S (acylamino group), —NHSO ₂ R _5S (alkyl). A sulfonylamino group, an arylsulfonylamino group, or a heterocyclic sulfonylamino group) or —NHCONHR _5S (ureido group). M represents a hydrogen atom or a counter cation, has the same meaning as M in the general formula (IV), and the preferred range is also the same.
R _4S is preferably —SO ₃ M, —NO ₂ , —NHCOR _5S , or —NHSO ₂ R _5S (preferably an alkylsulfonylamino group), and —SO ₃ M, —NO ₂ or —NHCOR _5S . It is more preferable from the viewpoint of the associativity of the colorant and the intermolecular interaction, particularly preferably —NO ₂ or —NHCOR _5S , and most preferably —NHCOR _5S .

R _5S represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent.
Specific examples of the alkyl group, aryl group, or heterocyclic group represented by R _5S include the alkyl group, aryl group, or heterocyclic group mentioned in the above-mentioned substituent group A.
R _5S is preferably an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, and an alkyl group having 1 to 8 carbon atoms. Is more preferable, and an alkyl group having 1 to 6 carbon atoms is most preferable from the viewpoint of water solubility. R _5S may have a substituent, and examples of the substituent include a substituent selected from the substituent group A. R _5S preferably has no substituent (that is, is unsubstituted).

Specific examples of the colorant represented by the general formula (I), (IV), (IV-2), (V), or (VI) are shown below, and the colorant used in the present invention is as follows. It is not limited to the example of. In the following Examples, M of the ionic hydrophilic group _{(-SO 3 M, -CO 2 M} ) can be another cation or the hydrogen atom in place of the lithium ion. However, as described above, it is preferable that lithium ions have the highest abundance ratio, and it is most preferable that lithium ions are all lithium ions.

The content of the colorant represented by formula (I) in the ink composition of the present invention is preferably 0.01 to 10.0% by mass, based on the total mass of the ink composition, It is more preferably from 1 to 10.0% by mass.
When the ink composition of the present invention is used as a gray ink, the content of the compound represented by the general formula (I) is 0.1 to 10.0 mass% based on the total mass of the ink composition. It is preferably 0.2 to 7.0 mass%, more preferably 0.3 to 5.0 mass%, still more preferably 0.3 to 3.0 mass%. Particularly preferred is 0.5 to 2.0% by mass for the purpose of enhancing intermolecular interaction with the compound represented by the general formula (II) coexisting in the ink composition and for the case represented by the general formula (III). It is most preferable from the viewpoint of adjusting the gray hue with the toning agent.

  When the ink composition of the present invention is used as a black ink, the content of the colorant represented by the general formula (I) is 0.1 to 10.0% by mass based on the total mass of the ink composition. Is preferable, 0.5 to 7.0 mass% is more preferable, 1.0 to 6.0 mass% is still more preferable, and 3.0 to 5.5 mass% is preferable. Is particularly preferable, and the content of 3.5 to 5.0% by mass is preferable for the purpose of enhancing intermolecular interaction with the compound represented by the general formula (II) coexisting in the ink composition. It is most preferable from the viewpoint of adjusting the black hue with the toning agent represented.

(Compound represented by the general formula (II))
The compound represented by formula (II) contained in the ink composition of the invention will be described.

In the general formula (II), Ar ₂₀ represents a benzene ring or a naphthalene ring. R _{21 to} R ₂₈ each independently represent a hydrogen atom or a substituent. R ₂₁ and R ₂₂ may combine to form a ring. R ₂₃ and R ₂₄ may combine to form a ring. R ₂₅ and R ₂₆ may combine to form a ring. R ₂₇ and R ₂₈ may combine to form a ring. R ₂₉ represents a substituent. When Ar ₂₀ represents a benzene ring, k represents an integer of 0-4. When Ar ₂₀ represents a naphthalene ring, k represents an integer of 0 to 6. If R ₂₉ there are a plurality, may be with or different plural R ₂₉ are the same respectively. If R ₂₉ there are a plurality, may form a ring with a plurality of R ₂₉ is bonded. However, the compound represented by the general formula (II) has at least one hydrophilic group.

  The compound represented by the general formula (II) is preferably a colorless water-soluble planar compound having more than 10 delocalized π electrons in one molecule.

  When the number of π electrons forming the delocalized π electron system increases and the π electron system expands, it often has absorption in the visible region. Colorless in the present invention also includes a state in which the color is extremely slight within a range that does not affect the image. Further, the water-soluble compound represented by the general formula (II) may be a fluorescent compound, but is preferably a compound without fluorescence, and more preferably the wavelength (λmax) of the absorption peak on the longest wavelength side is 350 nm. The compound having a molar extinction coefficient of not more than 320 nm and not more than 10,000 is more preferable.

  The upper limit of the number of delocalized π electrons in one molecule of the compound represented by the general formula (II) is not particularly limited, but is preferably 80 or less, particularly preferably 50 or less, and particularly preferably 30 or less. preferable. Further, more than 10 π electrons may form one large delocalized system, or may form two or more delocalized systems. In particular, a compound having two or more aromatic rings in one molecule is preferable. The aromatic ring may be an aromatic hydrocarbon ring or an aromatic heterocycle containing a hetero atom, or may be a condensed ring to form one aromatic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a pyridine ring, a pyrimidine ring, a pyrazine ring and a triazine ring.

  The compound represented by the general formula (II) is preferably water-soluble, and is preferably a compound capable of dissolving at least 1 g or more in 100 g of water at 20 ° C. More preferably, it is a compound capable of dissolving 5 g or more, and most preferably 10 g or more.

The compound represented by the general formula (II) has at least one hydrophilic group in one molecule. In the case of a compound having two or more aromatic rings in one molecule, it is particularly preferable to have at least two hydrophilic groups bonded to the aromatic rings in the molecule.
The hydrophilic group, a sulfo group _(-SO 3 M), a carboxyl group (-COOM), hydroxy group, phosphoric acid group (-PO _{(OM) 2),} a carbonamido group, a sulfonamido group, a quaternary ammonium group But is not limited to. As the hydrophilic group, an ionic hydrophilic group is preferable, a sulfo group (—SO ₃ M) and a carboxyl group (—COOM) are more preferable, and a sulfo group (—SO ₃ M) is most preferable.
The compound represented by the general formula (II) preferably has at least one ionic hydrophilic group.
M represents a hydrogen atom or a counter cation. The counter cation is not particularly limited, and examples thereof include alkali metal ions, ammonium ions, and organic cations (tetramethylammonium, guanidinium, pyridinium, etc.).
M is preferably a hydrogen atom, an ammonium ion or an alkali metal ion, more preferably an alkali metal ion, further preferably a lithium ion, a sodium ion or a potassium ion, and a lithium ion or a sodium ion. Is particularly preferable. The counter cation may be a single salt or a mixed salt.

The compound represented by the general formula (II) preferably has 1 to 10 hydrophilic groups, and more preferably 2 to 8 hydrophilic groups in one molecule.
The compound represented by the general formula (II) preferably has 2 to 6 ionic hydrophilic groups, and more preferably 2 to 4 ionic hydrophilic groups in one molecule.
At least one of R _{21 to} R _{29 in} the general formula (II) preferably has an ionic hydrophilic group, more preferably has —SO ₃ M, and 2 to 6 of R _{21 to} R ₂₉ are more preferably having a -SO _{3 M,} but one to four of R 21 _{to R 29} particularly preferably has a -SO ₃ M.

In formula (II), R _{21 to} R ₂₈ each independently represent a hydrogen atom or a substituent, and examples of the substituent include the substituents selected from the above-mentioned Substituent Group A. As the substituent, an alkyl group, an aryl group, an aralkyl group, a heterocyclic group, an alkoxy group, an aryloxy group, a hydroxyl group, an amino group (including an anilino group and a heterocyclic amino group), an acyl group, an acylamino group, a ureido group, Examples thereof include a halogen atom, a sulfamoyl group, a carbamoyl group, a sulfonamide group, a sulfonyl group, a sulfenyl group, a sulfinyl group and a hydrophilic group, which may further have a substituent.
It is preferable that R _{21 to} R ₂₈ each independently represent a hydrogen atom or an alkyl group. The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and most preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group preferably has the above-mentioned hydrophilic group as a substituent from the viewpoint of storage stability of the water-based ink.

R ₂₁ and R ₂₂ , R ₂₃ and R ₂₄ , R ₂₅ and R ₂₆ , and R ₂₇ and R ₂₈ may be bonded to each other to form a ring. The ring is not particularly limited, but may be an aromatic ring or a non-aromatic ring, and is preferably a 5-membered ring or a 6-membered ring. Further, the ring may contain a hetero atom (for example, an oxygen atom, a nitrogen atom, a sulfur atom) in addition to the nitrogen atom to which R _{21 to} R ₂₈ are bonded.

R ₂₉ represents a substituent, and examples of the substituent include the substituents selected from the aforementioned substituent group A. As the substituent, an alkyl group, an aryl group, an aralkyl group, a heterocyclic group, an alkoxy group, an aryloxy group, a hydroxyl group, an amino group (including an anilino group and a heterocyclic amino group), an acyl group, an acylamino group, a ureido group, Examples thereof include a halogen atom, a sulfamoyl group, a carbamoyl group, a sulfonamide group, a sulfonyl group, a sulfenyl group, a sulfinyl group and a hydrophilic group, which may further have a substituent.
If R ₂₉ there are a plurality, may be with or different plural R ₂₉ are the same respectively. If R ₂₉ there are a plurality, may form a ring with a plurality of R ₂₉ is bonded. The ring is not particularly limited, but may be an aromatic ring or a non-aromatic ring, and is preferably a 5-membered ring or a 6-membered ring. Further, the above ring may contain a hetero atom (eg, oxygen atom, nitrogen atom, sulfur atom).

In the general formula (II), Ar ₂₀ represents a benzene ring or a naphthalene ring, preferably a benzene ring.
When Ar ₂₀ represents a benzene ring, k represents an integer of 0 to 4, preferably an integer of 0 to 2, and more preferably 0 or 1.
When Ar ₂₀ represents a naphthalene ring, k represents an integer of 0 to 6, preferably an integer of 0 to 4, more preferably an integer of 0 to 2, and further preferably 0 or 1. preferable.

  Specific examples of the compound represented by formula (II) are shown below, but the invention is not limited thereto.

The content of the compound represented by the general formula (II) in the ink composition of the present invention is preferably 0.01 to 10.0 mass% based on the total mass of the ink composition, and 0.1 It is more preferable that the content is ˜10.0 mass%.
When the ink composition of the present invention is used as a gray ink, the content of the compound represented by the general formula (II) is 0.1 to 10.0% by mass based on the total mass of the ink composition. It is preferably 0.2 to 7.0 mass%, more preferably 0.3 to 5.0 mass%, still more preferably 0.3 to 3.0 mass%. Particularly preferred is 0.5 to 1.5% by mass, and it is most preferred for enhancing the intermolecular interaction with the colorant represented by the general formula (I) that coexists in the ink composition.

  When the ink composition of the present invention is used as a black ink, the content of the compound represented by the general formula (II) is 0.1 to 10.0% by mass based on the total mass of the ink composition. It is preferably 0.5 to 7.0 mass%, more preferably 1.0 to 6.0 mass%, still more preferably 3.0 to 5.5 mass%. It is particularly preferable that the content is 3.0 to 5.0% by mass, and the most preferable reason is to enhance the intermolecular interaction with the colorant represented by the general formula (I) coexisting in the ink composition.

  The compound represented by the general formula (II) can be synthesized by a known method (for example, the method described in JP-A-2005-105261).

(Toning agent represented by general formula (III))
The ink composition of the present invention contains a toning agent represented by the following general formula (III).
By containing the toning agent represented by the following general formula (III), the ink composition of the present invention is excellent in terms of gray to black color tone, print density and fading balance.

  In general formula (III), M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. Z represents a divalent linking group.

In the general formula (III), M represents a hydrogen atom or a counter cation, preferably a hydrogen atom, an ammonium ion or an alkali metal ion, and more preferably an alkali metal ion. M is preferably a lithium ion, a sodium ion or a kalim ion, particularly preferably a lithium ion or a sodium ion, and among them, the lithium ion enhances the water solubility of the azo dye represented by the general formula (III) and improves the ink storage stability. It is particularly preferable because it improves the efficiency. M does not have to be all lithium ions, but it is preferable that the counter cation having the highest abundance ratio is lithium ion.
When the highest abundance ratio of M is lithium ion, M other than lithium ion is hydrogen atom, alkali metal ion (for example, sodium ion, potassium ion) quaternary ammonium ion, quaternary phosphonium ion, sulfonium. Examples include ions. The amount of lithium ions is preferably 50% or more, preferably 60% or more, more preferably 80% or more, particularly preferably 90% or more, and the upper limit is preferably 100% with respect to the entire M.

In the general formula (III), Z represents a divalent linking group, an alkylene group, an alkenylene group, -CO -, - _SO n - (n represents 0, 1, or 2), heterocyclic group, - It is preferable to represent O- and a divalent group in which these linking groups are combined. Z is preferably an alkylene group having a total carbon number of 1 to 5, a phenylene group, -CO-, a 5- or 6-membered nitrogen-containing heterocyclic group, more preferably -CO-, or a 6-membered nitrogen-containing heterocyclic group, Among them, -CO- or s-triazine ring is preferable, and -CO- is particularly preferable from the viewpoint of simultaneously providing the association property of the azo dye molecule and the water solubility of the azo dye.

  In the general formula (III), when the divalent linking group represented by Z can further have a substituent, it may have a substituent. Examples of the substituent include the substituents selected from the above-mentioned substituent group A.

Specific examples of the toning agent represented by the general formula (III) are shown below, but the invention is not limited to the following examples. In the following specific examples, M of the ionic hydrophilic group (—SO ₃ M) may be another cation or a hydrogen atom instead of the lithium ion. However, as described above, it is preferable that lithium ions have the highest abundance ratio, and it is most preferable that lithium ions are all lithium ions.

The content of the toning agent represented by the general formula (III) in the ink composition of the present invention is preferably 0.01 to 10.0 mass% based on the total mass of the ink composition, and 0 More preferably, it is 0.05 to 5.0 mass%.
When the ink composition of the present invention is used as a gray ink, the content of the toning agent represented by the general formula (III) is 0.01 to 5.0 mass based on the total mass of the ink composition. %, More preferably 0.03 to 3.0% by mass, further preferably 0.05 to 1.0% by mass, and 0.05 to 0.50% by mass. From the viewpoint of hue adjustment (neutral gray toning) with the colorant represented by the general formula (I) coexisting in the ink composition, it is particularly preferably 0.05 to 0.10% by mass. preferable.

  When the ink composition of the present invention is used as a black ink, the content of the toning agent represented by the general formula (III) is 0.10 to 10.0 mass based on the total mass of the ink composition. %, More preferably 0.50 to 5.0% by mass, further preferably 1.0 to 4.0% by mass, and 1.0 to 3.0% by mass. From the viewpoint of adjusting the hue (black toning) with the colorant represented by the general formula (I) coexisting in the ink composition, 1.5 to 2.0% by mass is most preferable. ..

The preferable compounding ratio of the colorant represented by the general formula (I) / the compound represented by the general formula (II) / the toning agent represented by the general formula (III) in the ink composition of the present invention is the ink composition. Based on the total mass of the object,
Colorant represented by general formula (I) (0.01 to 10.0% by mass) / compound represented by general formula (II) (0.01 to 10.0% by mass) / general formula (III) Is preferably a toning agent (0.01 to 10.0% by mass),
Colorant represented by general formula (I) (0.05 to 5.0 mass%) / compound represented by general formula (II) (0.05 to 5.0 mass%) / general formula (III) It is more preferable that it is a toning agent represented by (0.05 to 5.0% by mass).

When the ink composition of the present invention is used as a gray ink,
Based on the total mass of the ink composition,
Colorant represented by general formula (I) (0.30 to 5.0 mass%) / compound represented by general formula (II) (0.30 to 5.0 mass%) / general formula (III) Is preferably a toning agent (0.05 to 1.0% by mass),
Colorant represented by general formula (I) (0.30 to 3.0 mass%) / compound represented by general formula (II) (0.30 to 3.0 mass%) / general formula (III) Is more preferably a toning agent (0.05 to 0.5% by mass),
Colorant represented by general formula (I) (0.50 to 2.0 mass%) / compound represented by general formula (II) (0.50 to 1.5 mass%) / general formula (III) It is more preferable that the toning agent is represented by (0.05 to 0.10% by mass).

When the ink composition of the present invention is used as a black ink,
Based on the total mass of the ink composition,
Colorant represented by the general formula (I) (1.0 to 6.0 mass%) / compound represented by the general formula (II) (1.0 to 6.0 mass%) / general formula (III) Is preferably a toning agent represented by (1.0 to 4.0% by mass),
Colorant represented by general formula (I) (3.0 to 5.5 mass%) / compound represented by general formula (II) (3.0 to 5.5 mass%) / general formula (III) Is more preferably a toning agent represented by (1.0 to 3.0% by mass),
Colorant represented by the general formula (I) (3.5 to 5.0 mass%) / compound represented by the general formula (II) (3.0 to 5.0 mass%) / general formula (III) It is more preferable that it is a toning agent represented by (1.5 to 2.0 mass%).

(Magenta dye)
The ink composition of the present invention preferably contains a magenta dye as a toning agent in order to improve the color tone from gray to black, and is represented by any one of the following general formulas (M1) to (M8). It is more preferable to include a toning agent. Among them, it is particularly preferable to contain the toning agent represented by the following general formula (M7) or (M8), and it is most preferable to contain the toning agent represented by the following general formula (M7).

In formula (M1), R ₄₁ and R ₄₂ each independently represent a substituent. p1 and p2 each independently represent an integer of 0 to 5. When a plurality of R ₄₁ and R ₄₂ are present, they may be the same or different. At least two R _41's may combine with each other to form a ring. At least two R _42's may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M2), Ar ₁ and Ar ₂ each independently represent an aromatic group which may have a substituent or a heterocyclic group which may have a substituent. L ₁ represents a divalent linking group. Z ₁ and Z ₂ each independently represent —OM ′ or a halogen atom. M and M ′ each independently represent a hydrogen atom or a counter cation. The plurality of M may be the same or different. When there are a plurality of M ′, the plurality of M ′ may be the same or different.

In formula (M3), R ₄₃ and R ₄₄ each independently represent a substituent. p3 and p4 each independently represent an integer of 0 to 5. When a plurality of R ₄₃ and R ₄₄ are present, they may be the same or different. At least two R ₄₃ may combine with each other to form a ring. At least two R ₄₄ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M4), R ₄₅ , R _46, and R ₄₇ each independently represent a hydrogen atom or a substituent. R ₄₆ and R ₄₇ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M5), R _{51 to} R ₅₁₂ each independently represent a hydrogen atom or a substituent. R ₅₁ and R ₅₂ may combine with each other to form a ring. R ₅₃ and R ₅₄ may combine with each other to form a ring. At least two of R _{58 to} R ₅₁₂ may combine with each other to form a ring. The toning agent represented by formula (M5) has at least one —SO ₃ M. M represents a hydrogen atom or a counter cation.

In formula (M6), R _{61 to} R ₆₆ each independently represent a hydrogen atom or a substituent. At least two of R _{63 to} R ₆₆ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation.

In formula (M7), R _{71 to} R ₇₄ each independently represent a hydrogen atom or a substituent. L ₂ represents a divalent linking group. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M8), R _{81 to} R ₈₁₂ each independently represent a hydrogen atom or a substituent. At least two of R _{81 to} R ₈₅ may combine with each other to form a ring. At least two of R _{86 to} R ₈₁₀ may combine with each other to form a ring.

In the general formula (M1), R ₄₁ and R ₄₂ each independently represent a substituent, and examples of the substituent include the substituents selected from the above-mentioned Substituent Group A, such as an alkyl group, an aryl group, a halogen atom and an alkoxy group. group, an aryloxy group, a heterocyclic group, preferably an ionic hydrophilic group, a sulfo group _(-SO 3 M) or carboxy group (-COOM) is particularly preferred. M represents a hydrogen atom or a counter cation, preferably a hydrogen atom, an ammonium ion or an alkali metal ion, more preferably an alkali metal ion, and further preferably a lithium ion, a potassium ion or a sodium ion, It is particularly preferred to represent lithium or sodium ions, most preferably lithium ions.
M in the general formula (M1) represents a hydrogen atom or a counter cation, and the preferred range is the same as above.
p1 and p2 each independently represent an integer of 0 to 5, and preferably an integer of 0 to 3.
At least two R ₄₁ may combine with each other to form a ring, and at least two R ₄₂ may combine with each other to form a ring. The ring is preferably an aromatic ring, more preferably a benzene ring. The above ring may have a substituent, and examples of the substituent include the substituents selected from the above-mentioned substituent group A.

In the general formula (M2), Ar ₁ and Ar ₂ each independently represent an aromatic group which may have a substituent or a heterocyclic group which may have a substituent, and examples of these include those described above. The thing mentioned as the substituent group A can be mentioned. Ar ₁ and Ar ₂ preferably represent an aromatic group which may have a substituent.
L ₁ represents a divalent linking group, preferably —NH—, an aromatic group, a heterocyclic group, or a divalent linking group formed by combining these. The divalent linking group may further have a substituent, and examples of the substituent include the substituents selected from the above-mentioned substituent group A.
M represents a hydrogen atom or a counter cation, and the preferable range is the same as M in the general formula (M1).
Z ₁ and Z ₂ each independently represent -OM 'or a halogen atom, preferably -OM' or a chlorine atom.
M'represents a hydrogen atom or a counter cation. Specific examples and preferred ranges in the case where M ′ represents a counter cation are the same as those in the case where M above represents a counter cation. It is preferable that M ′ represents a hydrogen atom.

In formula (M3), R ₄₃ and R ₄₄ each independently represent a substituent, and examples of the substituent include the substituents selected from the above-mentioned Substituent Group A, such as an alkyl group, an aryl group, a halogen atom and an alkoxy group. A group, an aryloxy group, a heterocyclic group and an ionic hydrophilic group are preferred.
p3 and p4 each independently represent an integer of 0 to 5, preferably an integer of 0 to 3.
At least two R ₄₃ may combine with each other to form a ring, and at least two R ₄₄ may combine with each other to form a ring. The ring is preferably an aromatic ring, more preferably a benzene ring. The above ring may have a substituent, and examples of the substituent include the substituents selected from the above-mentioned substituent group A.
M represents a hydrogen atom or a counter cation, and the preferable range is the same as M in the general formula (M1).

In formula (M4), R ₄₅ , R _46, and R ₄₇ each independently represent a hydrogen atom or a substituent. Examples of the substituent include a substituent selected from the above-mentioned Substituent Group A, and an alkyl group, an aryl group, a halogen atom, an alkoxy group, an aryloxy group, a heterocyclic group and an ionic hydrophilic group are preferable.
R ₄₆ and R ₄₇ may combine with each other to form a ring, and the above ring may have a substituent.
M represents a hydrogen atom or a counter cation, and the preferable range is the same as M in the general formula (M1).

In formula (M5), R _{51 to} R ₅₄ and R _{56 to} R ₅₁₂ each independently represent a hydrogen atom or a substituent. Examples of the substituent include a substituent selected from the above-mentioned Substituent Group A, and an alkyl group, an aryl group, a halogen atom, an alkoxy group, an aryloxy group, a heterocyclic group and an ionic hydrophilic group are preferable.
In the general formula (M5), R ₅₅ represents a hydrogen atom or a substituent, and is preferably an electron-withdrawing group having a Hammett's substituent constant σp value of 0.2 or more, and a σp value of 0.30 or more. It is more preferably an electron-withdrawing group, more preferably an electron-withdrawing group having a σp value of 0.45 or more, and particularly preferably an electron-withdrawing group having a σp value of 0.60 or more. preferable. It is desirable that the σp value of R ₅₅ does not exceed 1.0. More specifically, R ₅₅ is an acyl group having a total carbon number of 2 to 20, an alkyloxycarbonyl group having a total carbon number of 2 to 20, a nitro group, a cyano group, an alkylsulfonyl group having a total carbon number of 1 to 20, and a total carbon number of 6. It is preferably an arylsulfonyl group having 20 to 20 carbon atoms, a carbamoyl group having 1 to 20 carbon atoms in total, or a halogenated alkyl group having 1 to 20 carbon atoms in total. R ₅₅ is more preferably a cyano group, an alkyloxycarbonyl group having 2 to 10 carbon atoms in total, an alkylsulfonyl group having 1 to 20 carbon atoms in total, or an arylsulfonyl group having 6 to 20 carbon atoms in total, and a cyano group, A methyloxycarbonyl group, a methylsulfonyl group, or a phenylsulfonyl group is particularly preferable, and a cyano group is most preferable.

R ₅₁ and R ₅₂ may be bonded to each other to form a ring, R ₅₃ and R ₅₄ may be bonded to each other to form a ring, and at least two of R _{58 to} R ₅₁₂ are bonded to each other to form a ring. May be formed. The above ring may have a substituent, and examples of the substituent include the substituents selected from the above-mentioned substituent group A.
The toning agent represented by formula (M5) has at least one —SO ₃ M. M represents a hydrogen atom or a counter cation, and the preferable range is the same as M in the general formula (M1).

In formula (M6), R _{61 to} R ₆₆ each independently represent a hydrogen atom or a substituent. Examples of the substituent include a substituent selected from the above-mentioned Substituent Group A, and an amino group, an alkyl group, an aryl group, a halogen atom, an alkoxy group, an aryloxy group, a heterocyclic group and an ionic hydrophilic group are preferable.
At least two of R _{63 to} R ₆₆ may combine with each other to form a ring. The above ring may have a substituent, and examples of the substituent include the substituents selected from the above-mentioned substituent group A.
M represents a hydrogen atom or a counter cation, and the preferable range is the same as M in the general formula (M1).

In formula (M7), R _{71 to} R ₇₄ each independently represent a hydrogen atom or a substituent. Examples of the substituent include a substituent selected from the above-mentioned Substituent Group A, and an amino group, an alkyl group, an aryl group, a halogen atom, an alkoxy group, an aryloxy group, a heterocyclic group and an ionic hydrophilic group are preferable.
L ₂ represents a divalent linking group, preferably an alkylene group, an arylene group, a heterocyclic group, or a divalent linking group formed by combining these. The divalent linking group may have a substituent, and examples of the substituent include the substituents selected from the above-mentioned substituent group A.
M represents a hydrogen atom or a counter cation, and the preferable range is the same as M in the general formula (M1).

In formula (M8), R _{81 to} R ₈₁₂ each independently represent a hydrogen atom or a substituent. Examples of the substituent include a substituent selected from the above-mentioned Substituent Group A, and an amino group, an alkyl group, an aryl group, a halogen atom, an alkoxy group, an aryloxy group, a heterocyclic group and an ionic hydrophilic group are preferable.
At least two of R _{81 to} R ₈₅ may be bonded to each other to form a ring, and at least two of R _{86 to} R ₈₁₀ may be bonded to each other to form a ring. The above ring may have a substituent, and examples of the substituent include the substituents selected from the above-mentioned substituent group A.
R ₈₁ , R ₈₅ , R ₈₆ , and R ₈₁₀ preferably each independently represent an alkyl group, and more preferably represent an alkyl group having 1 to 6 carbon atoms.
It is preferable that R ₈₁₁ and R ₈₁₂ each independently represent a hydrogen atom or a sulfo group (—SO ₃ M), and more preferably a sulfo group (—SO ₃ M). M represents a hydrogen atom or a counter cation, and the preferable range is the same as M in the general formula (M1).
R ₈₂ , R ₈₃ , R ₈₄ , R ₈₇ , R ₈₈ , and R ₈₉ each independently represent a hydrogen atom, an alkyl group, a sulfo group (-SO ₃ M), or an arylsulfonylamino group which may have a substituent. It is preferable that at least R ₈₄ and R ₈₉ each independently represent an arylsulfonylamino group which may have a substituent. Examples of the substituent include a substituent selected from the above-mentioned Substituent Group A, an ionic hydrophilic group is preferable, and a sulfo group (—SO ₃ M) is more preferable. M represents a hydrogen atom or a counter cation, and the preferable range is the same as M in the general formula (M1).

Specific examples of the toning agent represented by any of the general formulas (M1) to (M8) are shown below, but are not limited thereto. In the following structural formulae, Me represents a methyl group, Et represents an ethyl group, (i) Pr and Pr (i) represent isopropyl groups, t-Bu represents a tert-butyl group, and (n) C ₅ H ₁₁ or C ₅ H ₁₁ (n) represents an n-pentyl group. M represents a hydrogen atom or a counter cation.

The content of the magenta dye in the ink composition of the present invention varies depending on the color value (coloring power per unit weight) of the dye used, but is 0.01 to 10.0 mass% based on the total mass of the ink composition. Is preferable, and it is more preferable that it is 0.05 to 5.0 mass%.
When the ink composition of the present invention is used as a gray ink, the magenta dye content is preferably 0.01 to 5.0% by mass, based on the total mass of the ink composition, and 0.03% by mass. To 3.0 mass% is more preferable, 0.05 to 2.0 mass% is still more preferable, 0.05 to 1.0 mass% is particularly preferable, and 0.05 to 0 mass%. From the viewpoint of hue adjustment (neutral gray toning) with the colorant represented by the general formula (I) coexisting in the ink composition, it is most preferably 10% by mass.

  When the ink composition of the present invention is used as a black ink, the magenta dye content is preferably 0.10 to 10.0 mass% based on the total mass of the ink composition, and 0.50. To 7.0 mass% is more preferable, 1.0 to 6.0 mass% is still more preferable, 1.0 to 4.0 mass% is particularly preferable, 1.0 to 2 It is most preferably 0.0% by mass from the viewpoint of hue adjustment (black toning) with the colorant represented by the general formula (I) coexisting in the ink composition.

(Other toning agents)
The ink composition of the present invention may contain other toning agent.
Examples of other toning agents include dyes having the following structures.

In addition to the toning dyes 1 to 6, the toning dyes that can be contained in the ink composition of the present invention are exemplified below, but the toning dyes are not limited thereto.
C. I. Direct Yellow 9, 11, 28, 29, 35, 39, 41, 53, 59, 68, 87, 93, 95, 96, 106, 108, 109, 122, 130, 142, 144, 161, 163, etc. ． I. Acid Yellow 19, 39, 49, 50, 61, 64, 79, 110, 127, 135, 143, 151, 159, 169, 174, 190, 195, 196, 197, 199, 218, 219, 222, 227, etc. C. I. Reactive Yellow 2, 3, 13, 14, 15, 17, 18, 23, 24, 25, 26, 27, 29, 35, 37, 41, 42, etc. C.I. I. Basic Yellow 1, 2, 4, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 39, 40, etc.

The ink composition of the present invention may or may not contain other toning agent, but in the case of containing it, the content of the other toning agent in the ink composition of the present invention (plural kinds) In the case of, the total amount) is preferably in the following range based on the total mass of the ink composition of the present invention.
When the ink composition of the present invention is used as a gray ink, it is preferably 0.01 to 1.0% by mass, more preferably 0.01 to 0.08% by mass, and 0.01 to It is more preferably 0.05% by mass, and 0.01 to 0.3% by mass adjusts the hue with the colorant represented by the general formula (I) coexisting in the ink composition (neutral gray). Most preferable from the viewpoint of (toning).
When the ink composition of the present invention is used as a black ink, it is preferably 0.10 to 5.0% by mass, more preferably 0.10 to 3.0% by mass, and 0.10 to 2% by mass. 0.0 mass% is more preferable, 0.10 to 1.5 mass% is particularly preferable, and 0.20 to 1.0 mass% is a general formula coexisting in the ink composition ( It is most preferable from the viewpoint of hue adjustment (black toning) with the colorant represented by I).

<Chelating agent>
The ink composition of the present invention may contain a chelating agent.
Chelating agents (also referred to as "chelating agents") are compounds that bind to inorganic or metal cations (particularly preferably polyvalent cations) to form chelate compounds.
In the present invention, the chelating agent has a function of preventing the formation and growth of insoluble deposits derived from an inorganic or metal cation (particularly a polyvalent cation) in the aqueous ink composition (that is, functions as a solubilizer).
The ink composition (water-based ink composition) of the present invention contains a chelating agent, so that it is possible to suppress the generation of deposits even during long-term storage of the water-based ink composition, and the water-based ink composition after long-term storage When an image is printed by an inkjet printer using the ink as an inkjet recording ink, the ink clogging in nozzles and the like hardly occurs, and a high-quality printed matter can be obtained. The chelating agent usable in the present invention is not particularly limited, and various kinds can be used.

  As a chelating agent, a chelating action forms a complex with a cation present in the ink composition (water-based ink composition) to solubilize the water-based ink composition, which is effective in suppressing the generation and growth of deposits. Various agents can be used alone or in combination of two or more, but water-soluble compounds are preferable.

  Examples of the chelating agent include ethylenediaminetetraacetic acid (EDTA) or a salt thereof (eg, EDTA-4 sodium (4 sodium salt), EDTA-4 lithium (4 lithium salt), etc.), picolinic acid or a salt thereof (eg, picoline). Acid sodium salt), quinolinic acid or a salt thereof (for example, sodium quinolinate), 1,10-phenanthroline, 8-hydroxyquinoline, 3-hydroxy-2,2′-iminodisuccinate tetrasodium, methylglycine diacetic acid (MGDA) or Salts thereof, L-glutamic acid diacetic acid (GLDA) or salts thereof, L-aspartic acid diacetic acid (ASDA) or salts thereof, hydroxyethyliminodiacetic acid (HIDA) or salts thereof, 3-hydroxy-2,2′-iminodisuccinate Examples thereof include acid (HIDS) or a salt thereof, dicarboxymethylglutamic acid (CMGA) or a salt thereof, (S, S) -ethylenediaminedisuccinic acid (EDDS) or a salt thereof, and the like. As the salt of the chelating agent, for example, salts of ammonium, amine and the like are preferable in addition to monovalent metal salts such as sodium, potassium and lithium. Among these chelating agents, the decay of the chelating action with respect to the pH change of the ink composition is even smaller. Therefore, a chelating action is exhibited in a wider range of pH, and it is possible to further improve the adaptability to pH changes of the ink composition such as changes with time.

The content of the chelating agent is preferably 0.001% by mass or more and 1.1% by mass or less based on the total mass of the ink composition. It is more preferably 0.001% by mass or more and 0.5% by mass or less, and even more preferably 0.001% by mass or more and 0.3% by mass or less.
When the content of the chelating agent is 0.001% by mass or more, the chelating effect can be effectively exhibited, and when the content of the chelating agent is 1.1% by mass or less, the addition of the chelating agent causes the dye ink composition to be added. It is possible to prevent the viscosity from increasing excessively and the pH from increasing excessively.
Further, in the ink composition, the chelating agent and the dye (the “dye” here is a colorant represented by the general formula (I), a toning agent represented by the general formula (III), and other). (Meaning all dyes including magenta dyes which may be used in combination) (content based on mass of chelating agent: content based on mass of dye) is 0.0001: 1 to 0. It is preferably in the range of 15: 1 (chelating agent: dye is preferably 0.0001 to 0.15). The range is more preferably 0.0001: 1 to 0.05: 1, and further preferably 0.0002: 1 to 0.005: 1.

  The metal that may form a metal salt is a metal that may be mixed in the dye manufacturing process or contained in the ink container of the ink composition and eluted in the ink composition. With the ratio, it is possible to effectively suppress the generation of foreign matter that causes the clogging of the inkjet head. Further, a chelating effect can be effectively exhibited, and it is possible to suppress an excessive increase in viscosity of the ink composition and an excessive increase in pH.

  Examples of the use of the ink composition of the present invention include image recording materials for forming images. Specifically, thermal recording materials, pressure sensitive recording materials, including inkjet recording materials described in detail below. , A recording material using an electrophotographic method, a transfer type silver halide photosensitive material, a printing ink, a recording pen, and the like, preferably an inkjet recording material, a heat-sensitive recording material, a recording material using an electrophotographic method, and more preferably It is an inkjet recording material.

  In addition, the ink composition of the present invention records and reproduces a color image used in a solid-state imaging device such as a CCD (Charge-Coupled Device) or a display such as an LCD (Liquid Crystal Display) or a PDP (Plasma Display Panel). It can also be applied to the color filters of and the dyeing solution for dyeing various fibers.

  The ink composition of the present invention can be used by adjusting physical properties such as solubility, dispersibility, and heat transferability suitable for its use with a substituent. Further, the dye used in the present invention can be used in a dissolved state, an emulsified dispersed state, or even a solid dispersed state depending on the system used.

  The ink composition of the present invention is particularly suitable as an ink for inkjet recording.

The ink composition of the present invention uses water as a medium and, if necessary, further uses a lipophilic medium or an aqueous medium to dissolve and / or disperse a colorant, a toning agent, and an additive therein. It can be produced by
Examples of water include deionized water, ultrafiltered water, reverse osmosis water, pure water such as distilled water, and ultrapure water.

The ink composition of the present invention may contain other solvent in addition to water. As the other solvent, a water-miscible organic solvent is preferable.
Examples of water-miscible organic solvents are alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyhydric alcohols. Classes (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), glycol derivatives (for example, Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol Diacetate, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monophenyl ether), amine (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyl) Diethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine, triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine) and other polar solvents (for example, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl). Sulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone) are included. Two or more water-miscible organic solvents may be used in combination.

In the ink composition of the present invention, the content of water is preferably 40 to 80% by mass, more preferably 45 to 70% by mass, and more preferably 50 to 60% by mass based on the total mass of the ink composition. From the viewpoint of the ejection stability and the storage stability of the ink, it is more preferable that the content is% by mass.
When the ink composition of the present invention contains a water-miscible organic solvent, the content of the water-miscible organic solvent is preferably 10 to 55 mass% based on the total mass of the ink composition, 20 Is more preferably from 50 to 50% by mass, further preferably from 30 to 45% by mass.

  The ink of the present invention may contain other additives, if necessary, within a range that does not impair the effects of the present invention.

  Other additives include, for example, anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, permeation accelerators, UV absorbers, antiseptics, mildew-proofing agents, pH adjusting agents, surface tension adjusting agents, and deodorizing agents. Known additives such as foaming agents, viscosity modifiers, dispersants, dispersion stabilizers, rust preventives and chelating agents (described in JP-A-2003-306623) can be mentioned.

[Inkjet recording method]
The ink jet recording method of the present invention applies energy to the ink jet recording ink of the present invention to form a known image receiving material, that is, plain paper or resin-coated paper, for example, JP-A-8-169172 and JP-A-8-27693. No. 2-276670, No. 7-276789, No. 9-323475, No. 62-238783, No. 10-153989, No. 10-217473, No. 10-235995. Images are formed on inkjet-dedicated papers, films, electrophotographic co-papers, cloths, glass, metals, ceramics, etc. described in Japanese Patent Publication Nos. 10-337947, 10-217597, 10-337947, etc. To do.

  When forming an image, a polymer latex compound may be used together for the purpose of imparting glossiness and water resistance or improving weather resistance.

  The recording method of the inkjet recording method of the present invention is not limited, and known methods such as a charge control method of ejecting ink by using electrostatic attraction and a drop-on-demand method (pressure of oscillating pressure of a piezoelectric element) Pulse method), an acoustic ink jet method of converting an electric signal into an acoustic beam and irradiating the ink and ejecting the ink by using radiation pressure, and a thermal ink jet method of heating the ink to form bubbles and utilizing the generated pressure. It is used for methods. The ink jet recording method uses a method of ejecting a large number of low density ink called photo ink in a small volume, a method of improving image quality by using a plurality of inks having substantially the same hue but different densities, and a colorless transparent ink. Method is included.

  Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto.

Example 1
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-1) was prepared by filtering under reduced pressure with a microfilter having an average pore diameter of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Additive (P-4) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

  Proxel XLII (s) is a preservative manufactured by LONZA.

Example 2
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-2) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 1: M = Na ion) 0.08 g
Additive (P-4) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 3
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-3) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (Magenta dye 3: M = Na ion) 0.06g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 4
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-4) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (Magenta dye 7: M = Li ion) 0.07 g
Additive (P-4) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 5
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-5) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14 :: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 6
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-6) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 27 :: M = Na ion) 0.05 g
Additive (P-4) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 7
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-7) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (Magenta dye 30: M = Na ion) 0.05 g
Additive (P-4) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 8
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-8) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-3) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 9
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-9) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Colorant (Exemplary Compound I-17) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 10
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-10) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 1.0 g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 11
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-11) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 1.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 12
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-12) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-2) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 13
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-13) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-3) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 14
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-14) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-4) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 15
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-15) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplified compound III-5) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 16
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-16) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-6) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 17
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-17) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Colorant (Exemplary Compound I-21) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 18
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-18) was prepared by performing vacuum filtration with a microfilter having an average pore diameter of 0.25 μm.
Colorant (Exemplary Compound I-22) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 19
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-19) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (Magenta dye 4: M = Na ion) 0.08 g
Additive (P-4) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 20
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-20) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (Magenta dye 5: M = Na ion) 0.08 g
Additive (P-4) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 21
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-21) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Colorant (Exemplary Compound I-22) 0.7 g
Toning agent (Exemplified compound III-5) 0.1 g
Magenta dye (Magenta dye 9: M = Na ion) 0.2 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 22
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-22) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-1) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 23
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-23) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-2) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 24
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-23) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-17) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 25
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-25) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-25) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 34
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-34) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 1.0 g
EDTA (4 sodium salt) 0.01 g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 35
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-35) was prepared by performing vacuum filtration with a microfilter having an average pore diameter of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (Magenta dye 14: M = Li ion) 0.1 g
Additive (P-4) 1.0 g
EDTA (4 lithium salt) 0.01g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 36
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-36) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Colorant (Exemplary Compound I-5) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
EDTA (4 sodium salt) 0.01 g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 37
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-37) was prepared by performing vacuum filtration with a microfilter having an average pore diameter of 0.25 μm.
Colorant (Exemplary Compound I-5) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (Magenta dye 14: M = Li ion) 0.1 g
Additive (P-4) 0.5g
EDTA (4 lithium salt) 0.01g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 38
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-38) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Colorant (Exemplary Compound I-17) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
EDTA (4 sodium salt) 0.01 g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Example 39
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (G-39) was prepared by performing vacuum filtration with a microfilter having an average pore diameter of 0.25 μm.
Colorant (Exemplary Compound I-17) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (Magenta dye 14: M = Li ion) 0.1 g
Additive (P-4) 0.5g
EDTA (4 lithium salt) 0.01g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 1
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-1) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-3) 0.7 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative example 2
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-2) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-3) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 3
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-3) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 4
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-4) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (Comparative compound IR-1) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 5
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-5) was prepared by filtering under reduced pressure with a microfilter having an average pore size of 0.25 μm.
Coloring agent (Comparative compound IR-2) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 6
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-6) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (Comparative compound IR-3) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 7
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-7) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (Comparative compound IR-4) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 8
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-8) was prepared by vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (Comparative compound IR-5) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 9
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-9) was prepared by performing vacuum filtration with a microfilter having an average pore size of 0.25 μm.
Coloring agent (Comparative compound IR-6) 0.7 g
Toning agent (Exemplary compound III-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

Comparative Example 10
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 100 g, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, the ink for gray (GR-10) was prepared by vacuum filtration with a micro filter having an average pore size of 0.25 μm.
Coloring agent (exemplary compound I-1) 0.7 g
Toning agent (Comparative compound IIIR-1) 0.1 g
Magenta dye (magenta dye 14: M = Na ion) 0.1 g
Additive (P-3) 0.5g
Triethylene glycol 8.0g
Triethylene glycol monobutyl ether 7.6g
2-pyrrolidone 2.9 g
Glycerin 7.3g
Propylene glycol 0.3g
Proxel XLII (s) 0.1g

(Image recording and evaluation)
Image recording was performed and evaluated as follows using the ink prepared above. In each of the examples and the comparative examples, image recording was performed with the combination of the following inkjet printer and recording paper, and the practical skill was evaluated.
Each of the inks of Examples 1 to 25, 34 to 39, and Comparative Examples 1 to 10 was loaded in an ink cartridge, and an ink jet printer (Seiko Epson Corp .; PX-045A) was used to print photographic paper (Seiko Epson Corp. ) It is evaluated by using an image recorded on photographic paper <gloss>).

<Hue>
The printed sample was visually observed and evaluated according to the following three grades.
A: Neutral gray B: Gray that is a little reddish yellow, gray that is a little red, or gray that is a little blue C: A color that is clearly deviated from gray (when further toning is required)

<Print density (coloring power)>
A solid image (printed image at an applied voltage of 100%) was recorded using each ink with the combination of the inkjet printer and the recording paper described above.
The print density of the solid gray image created was measured using a reflection densitometer (trade name i1 PUBLISH PRO 2, manufactured by X-Rite), and the print density (Optical Density) when using a visual filter was 1.0 or more. The case was evaluated as A, the case of 0.8 or more and less than 1.0 as B, the case of 0.7 or more and less than 0.8 as C, and the case of less than 0.7 as D.

<Moisture resistance>
Print a toned gray staircase patch image, and after 24 hours at 25 ° C, reflect from each density area of the staircase patch part using an i1 PUBLISH PRO 2 densitometer equipped with a Status A filter (Visual) as standard equipment. The concentration (OD≈1.0) (L1, a1, b1) was measured. This image sample was stored for 7 days under the conditions of 45 ° C. and 85% relative humidity, and after being stored again, the (L2, a2, b2) at the location of the initial reflection density (OD≈1.0) was measured, and after the exposure test. The color difference (ΔE) was calculated as an index of discoloration and fading of the.
ΔE of (L1, a1, b1) and (L2, a2, b2) was calculated from the following calculation formula.
ΔE = [(L1-L2) ² + (a1-a2) ² + (b1-b2) ² ] ^1/2
ΔE was obtained from the above equation, and the moisture resistance was evaluated according to the following criteria.
A: When ΔE is less than 3 B: When ΔE is 3 or more and less than 10 C: When ΔE is 10 or more

<Light resistance>
Print a toned gray staircase patch image, and after 24 hours at 25 ° C, reflect from each density area of the staircase patch part using an i1 PUBLISH PRO 2 densitometer equipped with a Status A filter (Visual) as standard equipment. The density (OD≈1.0) (L3, a3, b3) was measured. This image sample was irradiated with xenon light (100,000 lux) for 28 days using a low-temperature cycle xenon weather meter (XL75 manufactured by Suga Test Instruments Co., Ltd.), and (L4 at an initial reflection density (OD≈1.0)). a4, b4) were measured, and the color difference (ΔE) was calculated as an index of discoloration / fading after the exposure test.
ΔE of (L3, a3, b3) and (L4, a4, b4) was calculated from the following calculation formula.
ΔE = [(L3-L4) ² + (a3-a4) ² + (b3-b4) ² ] ^1/2
ΔE was obtained from the above equation, and the light resistance was evaluated according to the following criteria.
A: When ΔE is less than 10 B: When ΔE is 10 or more and less than 20 C: When ΔE is 20 or more

<Ozone resistance>
Print a toned gray staircase patch image, and after 24 hours at 25 ° C, reflect from each density area of the staircase patch part using an i1 PUBLISH PRO 2 densitometer equipped with a Status A filter (Visual) as standard equipment. The concentration (OD≈1.0) (L5, a5, b5) was measured. While passing dry air through the double glass tube of the Siemens-type ozonizer, an AC voltage of 5 kV was applied, and using this, the ozone gas concentration was 10.0 ± 0.5 ppm (parts per million), room temperature (20 ° C.), dark place. The paper on which the image is formed is left in the box set for 3 days, and (L6, a6, b6) at the initial reflection density (OD≈1.0) is measured, and the discoloration / fading after the exposure test is performed. The color difference (ΔE) was calculated as an index. The ozone gas concentration in the box was set using an ozone gas monitor manufactured by APPLICS (model: OZG-EM-01).
ΔE of (L5, a5, b5) and (L6, a6, b6) was calculated from the following calculation formula.
ΔE = [(L5-L6) ² + (a5-a6) ² + (b5-b6) ² ] ^1/2
ΔE was obtained from the above formula, and ozone resistance was evaluated according to the following criteria.
A: When ΔE is less than 10 B: When ΔE is 10 or more and less than 20 C: When ΔE is 20 or more

Examples 26 to 30, Comparative Examples 11 to 13
Using the inks used in Examples 1, 5, 7, 9, 11 and Comparative Examples 1, 2, and 3, an inkjet printer and a printing paper were each taken with an inkjet printer (Seiko Epson Corp .; PX-045A). Inkjet printer (Canon Co., Ltd .; PIXUS Pro 9000MkII) and inkjet dedicated paper (Canon Co., Ltd .; Photo gloss paper PT-201) were used in place of the paper (Seiko Epson Corp. photo paper <Glossy>). An image was created and evaluated by the same operation except for the above (Examples 26, 27, 28, 29, 30 and Comparative Examples 11, 12, 13). As a result, Examples 26, 27, 28, 29, 30 and Comparative Examples 11, 12, 13 show the same effects as Examples 1, 5, 7, 9, 11 and Comparative Examples 1, 2, 3, respectively. It was confirmed.

Example 31
Deionized water was added to a mixture containing the following components in the following addition amounts to 100 g, and the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Thereafter, the pH was adjusted to 9.0 with a 10 mol / L lithium hydroxide aqueous solution, and vacuum filtration was performed using a microfilter having an average pore size of 0.25 μm to prepare a black ink (BK-31).
3.50 g of colorant (exemplary compound I-1)
1.50 g of toning agent (exemplary compound III-1)
Magenta dye (Magenta dye 14: M = Na ion) 1.50 g
Additive (P-3) 3.50 g
Glycerin 10.00g
Triethylene glycol 2.00 g
Triethylene glycol monobutyl ether 10.00g
2-pyrrolidone 2.00 g
Surfynol (manufactured by Air Products and Chemicals) 1.00 g
Proxel XLII (s) 0.11g

Example 32
Deionized water was added to a mixture containing the following components in the following addition amounts to 100 g, and the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Thereafter, the pH was adjusted to 9.0 with a 10 mol / L lithium hydroxide aqueous solution, and vacuum filtration was performed using a microfilter having an average pore size of 0.25 μm to prepare a black ink (BK-32).
3.50 g of colorant (exemplary compound I-1)
1.50 g of toning agent (exemplary compound III-1)
Magenta dye (Magenta dye 14: M = Na ion) 1.50 g
Additive (P-3) 5.00g
Glycerin 10.00g
Triethylene glycol 2.00 g
Triethylene glycol monobutyl ether 10.00g
2-pyrrolidone 2.00 g
Surfynol (manufactured by Air Products and Chemicals) 1.00 g
Proxel XLII (s) 0.11g

Example 33
Deionized water was added to a mixture containing the following components in the following addition amounts to 100 g, and the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Thereafter, the pH was adjusted to 9.0 with a 10 mol / L aqueous lithium hydroxide solution, and vacuum filtration was performed using a microfilter having an average pore size of 0.25 μm to prepare a black ink (BK-33).
Coloring agent (exemplary compound I-3) 4.50 g
1.50 g of toning agent (exemplary compound III-1)
Magenta dye (Magenta dye 14: M = Na ion) 1.50 g
Additive (P-3) 3.00 g
Glycerin 6.50g
1.90 g of 1,5-pentanediol
2-pyrrolidone 3.70 g
2.30 g of triethylene glycol
Surfynol (manufactured by Air Products and Chemicals) 0.50 g
Proxel XLII (s) 0.11g

Example 40
Deionized water was added to a mixture containing the following components in the following addition amounts to 100 g, and the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Thereafter, the pH was adjusted to 9.0 with a 10 mol / L aqueous lithium hydroxide solution, and vacuum filtration was performed using a microfilter having an average pore size of 0.25 μm to prepare a black ink (BK-40).
Colorant (Exemplary Compound I-17) 4.5 g
Toning agent (Exemplary compound III-1) 1.5 g
Magenta dye (magenta dye 14: M = Li ion) 1.5 g
Additive (P-4) 3.0 g
EDTA (4 lithium salt) 0.02g
Glycerin 6.5g
2.9 g of 1,5-pentanediol
2-pyrrolidone 3.7 g
2.3 g of triethylene glycol
Surfynol (manufactured by Air Products and Chemicals) 0.5g
Proxel XLII (s) 0.1g

Comparative Example 14
Deionized water was added to a mixture containing the following components in the following addition amounts to 100 g, and the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Thereafter, the pH was adjusted to 9.0 with a 10 mol / L lithium hydroxide aqueous solution, and vacuum filtration was performed using a microfilter having an average pore size of 0.25 μm to prepare a black ink (BKR-14).
3.50 g of colorant (exemplary compound I-1)
1.50 g of toning agent (exemplary compound III-1)
Magenta dye (Magenta dye 14: M = Na ion) 1.50 g
Glycerin 10.00g
Triethylene glycol 2.00 g
Triethylene glycol monobutyl ether 10.00g
2-pyrrolidone 2.00 g
Surfynol (manufactured by Air Products and Chemicals) 1.00 g
Proxel XLII (s) 0.11g

Comparative Example 15
Deionized water was added to a mixture containing the following components in the following addition amounts to 100 g, and the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Thereafter, pH was adjusted to 9.0 with a 10 mol / L aqueous lithium hydroxide solution, and vacuum filtration was performed using a microfilter having an average pore size of 0.25 μm to prepare a black ink (BKR-15).
Coloring agent (exemplary compound I-1) 4.50 g
1.50 g of toning agent (exemplary compound III-1)
Magenta dye (Magenta dye 14: M = Na ion) 1.50 g
Glycerin 6.50g
1.90 g of 1,5-pentanediol
2-pyrrolidone 3.70 g
2.30 g of triethylene glycol
Surfynol (manufactured by Air Products and Chemicals) 0.50 g
Proxel XLII (s) 0.11g

  Each of the inks of Examples 31 and 32 and Comparative Example 14 was loaded in an ink cartridge, and an ink jet printer (Seiko Epson Corp .; PX-045A) was used to print photo paper (Seiko Epson Corp. photo paper <gloss. >) Was used for evaluation.

  In the inks of Examples 33 and 40 and Comparative Example 15, each ink was loaded in an ink cartridge, and an ink jet printer (manufactured by Canon Inc .; PIXUS Pro9000MkII) and ink jet dedicated paper (manufactured by Canon Inc .; photo gloss paper PT-201). ), And evaluated using the image recorded by.

<Hue>
The printed sample was visually observed and evaluated according to the following three grades.
A: Black B: Black that is close to reddish yellow, black that is close to red, or black that is close to blue C: Color that clearly deviates from black (when further toning is required)

<Print density (coloring power)>
A solid image (printed image at an applied voltage of 100%) was recorded using each ink with the combination of the inkjet printer and the recording paper described above.

  The print density of the solid black image prepared was measured using a reflection densitometer (trade name: i1 PUBLISH PRO 2, manufactured by X-Rite), and the print density (Optical Density) when using a visual filter was 2.4 or more. The case was evaluated as A, the case of 2.2 or more and less than 2.4 as B, the case of 2.0 or more and less than 2.2 as C, and the case of less than 2.0 as D.

<Moisture resistance>
After printing the staircase patch image in black color and after 24 hours at 25 ° C, the reflection density was measured from each density area of the staircase patch part using the i1 PUBLISH PRO 2 densitometer equipped with the Status A filter (Visual) as standard. The (L1, a1, b1) of (OD≈1.0) was measured. This image sample was stored for 7 days under the conditions of 45 ° C. and 85% relative humidity, and after being stored again, the (L2, a2, b2) at the location of the initial reflection density (OD≈1.0) was measured, and after the exposure test. The color difference (ΔE) was calculated as an index of discoloration and fading of the.
ΔE of (L1, a1, b1) and (L2, a2, b2) was calculated from the following calculation formula.
ΔE = [(L1-L2) ² + (a1-a2) ² + (b1-b2) ² ] ^1/2
ΔE was obtained from the above equation, and the moisture resistance was evaluated according to the following criteria.
A: When ΔE is less than 3 B: When ΔE is 3 or more and less than 10 C: When ΔE is 10 or more

<Light resistance>
After printing the staircase patch image in black color and after 24 hours at 25 ° C, the reflection density was measured from each density area of the staircase patch part using the i1 PUBLISH PRO 2 densitometer equipped with the Status A filter (Visual) as standard. (L3, a3, b3) of (OD≈1.0) was measured. This image sample was irradiated with xenon light (100,000 lux) for 28 days using a low-temperature cycle xenon weather meter (XL75 manufactured by Suga Test Instruments Co., Ltd.), and (L4 at an initial reflection density (OD≈1.0)). a4, b4) were measured, and the color difference (ΔE) was calculated as an index of discoloration / fading after the exposure test.
ΔE of (L3, a3, b3) and (L4, a4, b4) was calculated from the following calculation formula.
ΔE = [(L3-L4) ² + (a3-a4) ² + (b3-b4) ² ] ^1/2
ΔE was obtained from the above equation, and the light resistance was evaluated according to the following criteria.
A: When ΔE is less than 10 B: When ΔE is 10 or more and less than 20 C: When ΔE is 20 or more

<Ozone resistance>
After printing a staircase patch image in black color and after 24 hours at 25 ° C, use the i1 PUBLISH PRO 2 densitometer equipped with a status A filter (Visual) as standard from each density range of the staircase patch part. (L5, a5, b5) of (OD≈1.0) was measured. While passing dry air through a double glass tube of a Siemens type ozonizer, an AC voltage of 5 kV was applied, and using this, ozone gas concentration was 10.0 ± 0.5 ppm, room temperature (20 ° C.), and a box set in a dark place. The paper on which the image is formed is left inside for 3 days, (L6, a6, b6) at the position of the initial reflection density (OD≈1.0) is measured, and the color difference (index of discoloration / fading after the exposure test ΔE) was calculated. The ozone gas concentration in the box was set using an ozone gas monitor manufactured by APPLICS (model: OZG-EM-01).
ΔE of (L5, a5, b5) and (L6, a6, b6) was calculated from the following calculation formula.
ΔE = [(L5-L6) ² + (a5-a6) ² + (b5-b6) ² ] ^1/2
ΔE was obtained from the above formula, and ozone resistance was evaluated according to the following criteria.
A: When ΔE is less than 10 B: When ΔE is 10 or more and less than 20 C: When ΔE is 20 or more

  The results of Examples and Comparative Examples are shown in Tables 1 and 2 below.

<Stability of ink ejection>
Regarding the ink ejection stability, the ink compositions prepared in Examples 1 to 25, 31 to 32, and 34 to 39 were filled in an ink cartridge for an inkjet recording device (trade name: PM-700C, manufactured by Seiko Epson Corporation). Then, after setting this cartridge in the inkjet recording device and confirming the ink ejection from all the nozzles, output to 100 sheets of A4 paper (inkjet dedicated paper, photo paper <gloss> manufactured by Seiko Epson Corp.), The following criteria evaluated.
Further, the ink compositions prepared in Examples 26 to 30, 33, and 40 were filled in an ink cartridge for an inkjet recording device (trade name: PIXUS Pro9000MkII, manufactured by Canon Inc.), and the cartridge was set in the inkjet recording device. After confirming the ink ejection from all the nozzles, the paper was output to 100 sheets of A4 paper (inkjet dedicated paper, manufactured by Canon Inc .; photo gloss paper PT-201) and evaluated according to the following criteria.
A: Almost no print disturbance from the start to the end of printing B: A small number of output with print disturbance C: A lot of output with print disturbance D: Disorder of print from start to finish

The ink ejection stability test was conducted immediately after the ink composition was prepared and after being stored in an ink cartridge at 40 ° C. and 80% relative humidity for 4 weeks.
In Table 3 below, the results when the ink composition immediately after preparation was used are shown in the column "immediately after ink preparation". The results of the case where the ink cartridge was stored for 4 weeks under the conditions of 40 ° C. and 80% relative humidity in the ink cartridge are shown in the column of “4 weeks after forced test”.

<Storage stability>
With respect to the ink compositions prepared in Examples 1 to 40, as a forced test, the ink storage stability was evaluated after storing at 60 ° C. for 4 weeks and after storing at 60 ° C. for 10 weeks.
A that maintains the same performance as the ink composition immediately after preparation, A, even one item of the evaluation items (hue, print density, moisture resistance, light resistance, ozone resistance, and ejection stability) after the forced test The decrease was designated as B and evaluated in two stages.

  The results of the examples are shown in Table 3 below.

From the above results, the ink of the example of the present invention is an ink composition capable of forming an image having excellent hue from gray to black, and printing density, and excellent moisture resistance, light resistance, and ozone resistance. I found out. In particular, the inks of the examples of the present invention were excellent in moisture resistance, and were excellent in terms of preservability of the inkjet print on natural aging (especially at high humidity). Furthermore, the ink composition of the present invention was excellent in storage stability after long-term storage, print quality of the ink after long-term storage, and ejection stability.

Claims (11)

An ink composition containing a colorant represented by the following general formula (I), water, a compound represented by the following general formula (II), and a toning agent represented by the following general formula (III).

In formula (I), R ₁ , R ₂ , and R ₄ each independently represent a hydrogen atom or a substituent. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. m represents an integer of 1 to 6. G represents a nitrogen atom or -C (-W) =. W represents an electron-withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃ represents an aromatic group which may have a substituent or a heterocyclic group which may have a substituent.

In the general formula (II), Ar ₂₀ represents a benzene ring or a naphthalene ring. R _{21 to} R ₂₈ each independently represent a hydrogen atom or a substituent. R ₂₁ and R ₂₂ may combine to form a ring. R ₂₃ and R ₂₄ may combine to form a ring. R ₂₅ and R ₂₆ may combine to form a ring. R ₂₇ and R ₂₈ may combine to form a ring. R ₂₉ represents a substituent. When Ar ₂₀ represents a benzene ring, k represents an integer of 0-4. When Ar ₂₀ represents a naphthalene ring, k represents an integer of 0 to 6. If R ₂₉ there are a plurality, may be with or different plural R ₂₉ are the same respectively. If R ₂₉ there are a plurality, may form a ring with a plurality of R ₂₉ is bonded. However, the compound represented by the general formula (II) has at least one hydrophilic group.

In general formula (III), M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. Z represents a divalent linking group. The ink composition according to claim 1, further comprising a toning agent represented by any one of the following general formulas (M1) to (M8).

In formula (M1), R ₄₁ and R ₄₂ each independently represent a substituent. p1 and p2 each independently represent an integer of 0 to 5. When a plurality of R ₄₁ and R ₄₂ are present, they may be the same or different. At least two R _41's may combine with each other to form a ring. At least two R _42's may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M2), Ar ₁ and Ar ₂ each independently represent an aromatic group which may have a substituent or a heterocyclic group which may have a substituent. L ₁ represents a divalent linking group. Z ₁ and Z ₂ each independently represent —OM ′ or a halogen atom. M and M ′ each independently represent a hydrogen atom or a counter cation. The plurality of M may be the same or different. When there are a plurality of M ′, the plurality of M ′ may be the same or different.

In formula (M3), R ₄₃ and R ₄₄ each independently represent a substituent. p3 and p4 each independently represent an integer of 0 to 5. When a plurality of R ₄₃ and R ₄₄ are present, they may be the same or different. At least two R ₄₃ may combine with each other to form a ring. At least two R ₄₄ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M4), R ₄₅ , R _46, and R ₄₇ each independently represent a hydrogen atom or a substituent. R ₄₆ and R ₄₇ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M5), R _{51 to} R ₅₁₂ each independently represent a hydrogen atom or a substituent. R ₅₁ and R ₅₂ may combine with each other to form a ring. R ₅₃ and R ₅₄ may combine with each other to form a ring. At least two of R _{58 to} R ₅₁₂ may combine with each other to form a ring. The toning agent represented by formula (M5) has at least one —SO ₃ M. M represents a hydrogen atom or a counter cation.

In formula (M6), R _{61 to} R ₆₆ each independently represent a hydrogen atom or a substituent. At least two of R _{63 to} R ₆₆ may combine with each other to form a ring. M represents a hydrogen atom or a counter cation.

In formula (M7), R _{71 to} R ₇₄ each independently represent a hydrogen atom or a substituent. L ₂ represents a divalent linking group. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.

In formula (M8), R _{81 to} R ₈₁₂ each independently represent a hydrogen atom or a substituent. At least two of R _{81 to} R ₈₅ may combine with each other to form a ring. At least two of R _{86 to} R ₈₁₀ may combine with each other to form a ring. The ink composition according to claim 1, wherein the colorant represented by the general formula (I) is a colorant represented by the following general formula (IV).

In general formula (IV), M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different. n represents 1 or 2. G represents a nitrogen atom or -C (-W) =. W and W ₁ each independently represent an electron withdrawing group having a Hammett's substituent constant σp value of 0.2 or more. R ₃₀ represents an optionally substituted aromatic group. R ₄ represents a hydrogen atom or a substituent. The colorant represented by the general formula (I) includes at least one selected from the colorant represented by the following general formula (V) and the colorant represented by the following general formula (VI). 4. The ink composition according to any one of 3 to 3.

In formulas (V) and (VI), R ₃₀ represents an aromatic group which may be substituted. R _4S represents _{-SO 3 M, -NO 2, -NHCOR} 5S, -NHSO 2 R 5S, or -NHCONHR _5S. R _5S represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent. M represents a hydrogen atom or a counter cation. The plurality of M may be the same or different.   The ink composition according to any one of claims 1 to 4, wherein the compound represented by the general formula (II) has at least one ionic hydrophilic group. The ink composition according to claim 1, wherein at least one of R _{21 to} R _{29 in} the general formula (II) has an ionic hydrophilic group.   The content of the compound represented by the general formula (II) is 0.5 to 1.5 mass% based on the total mass of the ink composition, and the content is for gray ink. The ink composition according to any one of items.   The content of the compound represented by the general formula (II) is 3.0 to 5.0% by mass, based on the total mass of the ink composition, and is for black ink. The ink composition according to any one of items.   The chelating agent is contained, and the content of the chelating agent is 0.001 to 0.3% by mass based on the total mass of the ink composition. Ink composition.   An inkjet recording ink containing the ink composition according to claim 1.   An inkjet recording method using the inkjet recording ink according to claim 10.