JP2021017471A - Ink, ink set, and printing method using the same - Google Patents

Abstract

To provide an aqueous ink that has a neutral hue and a high color density, and resists discoloration after deteriorating, particularly discoloration after exposed to ozone gas.SOLUTION: An ink contains a black dye represented by the formula (1), and a brown dye (where, Z is an optionally substituted naphthyl group. R1-R6 independently represent a hydrogen atom or a substituent. n is an integer of 1 or 2).SELECTED DRAWING: None

Description

The present invention relates to a water-based ink, an inkjet recording method using the ink, and a recording medium to which the ink is attached.

A recording method using an inkjet printer (inkjet recording method) is one of color recording methods. In the inkjet recording method, small droplets of ink are generated and attached to various recording media (paper, film, cloth, etc.) for recording. This method is quiet with less sound generation because the recording head and the recording medium do not come into direct contact with each other. In addition, it has the feature that the size and speed of the inkjet printer can be easily increased. For this reason, the inkjet recording method has rapidly become widespread in recent years, and is expected to grow significantly in the future. As the water-based ink for writing instruments and inkjet recording applications, an ink in which a colorant is dissolved in an water-based medium is generally used. A water-soluble organic solvent is usually added to these water-based inks in order to prevent clogging of the ink at the pen tip or the ink ejection nozzle. In addition, these inks provide a recorded image with sufficient density, do not cause clogging of the pen tip or nozzle, have good drying property on the recording medium, have less bleeding, and have storage stability. Performance such as excellent performance is required. Further, as the colorant, it is desirable that the colorant has high solubility in a water-soluble organic solvent added to water and ink. Further, the image recorded by the water-based ink is required to have various robustness such as water resistance, light resistance, gas resistance (particularly ozone resistance), and moisture resistance.

Black ink is an important ink used for both monocolor and full color images. However, there are many technical difficulties in developing a dye that has a neutral hue in both the dark and light gamuts, a high color density, and excellent fastness, and a great deal of research and development has been carried out. Few have sufficient performance. Therefore, it is generally practiced to prepare a black ink by mixing a plurality of various dyes. However, when ink is prepared by mixing multiple dyes, the hue differs depending on the material to be recorded, and the discoloration becomes particularly large due to deterioration due to light or gas or bleeding due to water, as compared with the case where ink is prepared with a single dye. Problems such as deterioration of storage stability are likely to occur, and there is a demand for black ink having color development, hue, and ozone resistance.

Japanese Patent No. 5624051 WO2008 / 096697 Japanese Patent No. 4764829 Japanese Patent No. 4677403

An object of the present invention is to provide a water-based ink having a neutral hue, a high color density, little discoloration during deterioration, and particularly little discoloration after exposure to ozone gas.

As a result of diligent studies to solve the above problems, the present inventors have found that an ink containing a specific black dye and a brown dye solves the above problems, and have completed the present invention.

That is, the present invention relates to the following 1) to 11).
1)
An ink containing a black dye represented by the following formula (1) and a brown dye.

(In formula (1), Z represents a naphthyl group which may have a substituent. R ^{1 to} R ⁶ each independently represent a hydrogen atom or a substituent. N represents an integer of 1 or 2. .)
2)
The ink according to 1), wherein the brown dye is a brown dye having an azo bond in the molecule.
3)
The ink according to 2), wherein the brown dye further has a triazine skeleton.
4)
The ink according to any one of 1) to 3), wherein the brown dye is represented by the following formula (2).

(In the formula (2), the ^{Q 8} are each independently of the ^{Q 1,} a hydrogen atom, a halogen atom, a sulfo group, a carboxy group, a sulfamoyl group, a carbamoyl group, C1-C4 alkyl group; C1-C4 alkoxy group; a hydroxy group, C1-C4 alkoxy group substituted with at least one group selected from the group consisting of C1-C4 alkoxy group, hydroxy C1-C4 alkoxy group, sulfo group, and carboxy group; C1-C4 alkylcarbonylamino group; carboxy C1-C4 alkylcarbonylamino group substituted with a group; ureido group; mono-C1-C4 alkyl ureido group; di-C1-C4 alkyl ureido group; at least one selected from the group consisting of a hydroxy group, a sulfo group, and a carboxy group. Mono-C1-C4 alkyl ureido groups substituted with different groups; di-C1-C4 alkyl ureido groups substituted with at least one group selected from the group consisting of hydroxy groups, sulfo groups, and carboxy groups; benzoylamino Group; A benzoylamino group in which the benzene ring is substituted with at least one group selected from the group consisting of a halogen atom, a C1-C4 alkyl group, a nitro group, a sulfo group, and a carboxy group; a benzenesulfonylamino group; or Represents a phenylsulfonylamino group in which the benzene ring is substituted with at least one group selected from the group consisting of halogen atoms, C1-C4 alkyl groups, nitro groups, sulfo groups, and carboxy groups.
X is a C1-C8 alkylene diamino group; a C1-C8 alkylene diamino group substituted with a hydroxy group or a carboxy group; an N- (C1-C4) alkyl- (C1-C6) alkylene diamino group; the alkyl moiety is a hydroxy group or N- (C1-C4) alkyl- (C1-C6) alkylene diamino group substituted with carboxy group; amino C1-C6 alkoxy C1-C6 alkylamino group; amino C1-C4 alkoxy C1-C4 alkoxy C1-C4 alkylamino Group; xylylene diamino group; piperazin-1,4-diyl group; piperazin-1,4-diyl group substituted with C1-C4 alkyl group or C1-C4 alkoxy group; and phenylenediamino group; Represents any group selected. )
5)
The ink according to any one of 1) to 4), which further contains a second black dye.
6)
The ink according to any one of 1) to 5), wherein the content mass% of the black dye represented by the above formula (1) in the ink is 0.1% to 3.5%.
7)
The ink according to any one of 1) to 6), wherein the mass ratio of the black dye represented by the above formula (1) to the brown dye is in the range of 4: 96 to 67:33.
8)
The ink according to any one of 1) to 7), further comprising at least one of a water-soluble organic solvent, a preservative, and a pH adjuster as an ink preparation agent.
9)
An ink set containing the ink according to any one of 1) to 8) and at least one ink selected from the group consisting of yellow ink, magenta ink, and cyan ink.
10)
A recording medium printed using the ink according to any one of 1) to 8) or the ink set according to 9).
11)
A printing method using the ink according to any one of 1) to 8) or the ink set according to 9).

The ink containing the black dye and the brown dye represented by the above formula (1) according to the present invention is suitably used as an ink for inkjet recording, and further, when recorded on a special paper for inkjet recording, the print density is extremely high. High in color, excellent in color playability, low in saturation, has a high-quality black hue, and is particularly excellent in ozone resistance. Therefore, the ink composition containing the azo compound of the present invention, a tautomer thereof, or a salt thereof is extremely useful as a black ink for inkjet recording.

Hereinafter, the present invention will be described in detail.
In the present specification, in order to avoid complication, the term “compound” may be abbreviated to include all of “compound”, “the tautomer” and “the salt”. Further, unless otherwise specified in the present invention, acidic functional groups such as sulfo groups and carboxyl groups are represented in the form of free acids.

[Black dye represented by formula (1)]
The ink contains a black dye represented by the above formula (1). In the above formula (1), Z represents a naphthyl group which may have a substituent. R ^{1 to} R ⁶ each independently represent a hydrogen atom or a substituent. n represents an integer of 1 or 2.

The above-mentioned substituent is not particularly limited, but for example, a hydroxy group, a halogen group, a cyano group, a carboxy group, a sulfo group, a phosphoric acid group, an aliphatic hydrocarbon group which may have a substituent, or a substituent may be used. An aromatic hydrocarbon group which may have a substituent, a heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an amino group which may have a substituent, Examples thereof include an amide group which may have a substituent.

Examples of the halogen group include a fluorine group, a chlorine group, a bromine group, an iodine group and the like.

Examples of the aliphatic hydrocarbon group in the aliphatic hydrocarbon group which may have the above substituent include a straight chain such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group and an n-octyl group. Examples thereof include a branched alkyl group such as an alkyl group, an iso-butyl group, a sec-butyl group and a t-butyl group, a cyclic alkyl group such as a cyclobutyl group and a cyclohexyl group, and the like.

Examples of the aromatic hydrocarbon group in the aromatic hydrocarbon group which may have the above-mentioned substituent include a phenyl group, a naphthyl group, an anthrasenyl group, a fluorenyl group and the like.

Examples of the heterocyclic group in the heterocyclic group which may have the above-mentioned substituent include a ring containing at least one atom selected from the group consisting of a nitrogen atom, a sulfur atom and an oxygen atom as a ring constituent component. Examples thereof include a pyrrole group, a furan group, a thiophene group, a pyrazole group, an imidazole group, a benzimidazole group, a thiazole group, a benzothiazole group, a naphthothiazole group, a thiazyl group, a benzothiazol group, a triazole group, a benzotriazole group and the like. Be done.

Examples of the alkoxy group in the alkoxy group which may have the above-mentioned substituent include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, a sec-butoxy group, a t-butoxy group and the like.

Examples of the amino group which may have the above-mentioned substituent include an amino group, a methylamino group, an ethylamino group, an n-propylamino group, an n-butylamino group, a phenylamino group, a naphthylamino group and a dimethylamino group. Examples thereof include a group, a diethylamino group, a diphenylamino group, an N-ethyl-N-methylamino group, an N-ethyl-N-phenylamino group and the like.

It has an aliphatic hydrocarbon group which may have the above substituent, an aromatic hydrocarbon group which may have a substituent, a heterocyclic group which may have a substituent, and a substituent. The substituent in the alkoxy group, the amino group which may have a substituent, and the amide group which may have a substituent is not particularly limited, and is, for example, a hydroxy group, a sulfo group, or phosphorus. Examples thereof include an acid group, a carboxy group and a cyano group.

In the black dye represented by the above formula (1), R ^{1 to} R ⁶ independently have a hydrogen atom, a cyano group, a carbamoyl group, and an aliphatic hydrocarbon group and a substituent which may have a substituent. It is preferable that it is any group selected from the group consisting of an alkoxy group which may have a substituent, and among these, R ^{1 to} R ⁴ are aliphatic hydrocarbons which may have a substituent. It is more preferably an alkoxy group having a group or a sulfo group as a substituent, particularly preferably an n-propoxy group having a methyl group or a sulfo group as a substituent, and R ¹ and R ³ are methyl groups, respectively. In addition, a combination in which R ² and R ⁴ are n-propoxy groups each having a sulfo group as a substituent is extremely preferable. The R ^5, more preferably be have a hydrogen atom or a substituent also aliphatic hydrocarbon group is preferably, it may have a substituent aliphatic hydrocarbon group, methyl It is particularly preferred to be a group. The R ⁶ is preferably any group selected from the group consisting of a hydrogen atom, a cyano group, and a carbamoyl group, and more preferably a cyano group.

The naphthyl group which may have the above-mentioned substituent is not particularly limited, and examples thereof include a naphthyl group which may have a hydroxy group, a sulfo group, a phosphoric acid group, a carboxy group or the like as a substituent. .. The number of substituents on the naphthyl group which may have the substituent is preferably 1 to 5, more preferably 1 to 4, particularly preferably 2 to 3, and 3 Is highly preferred. When the number of substituents on the naphthyl group which may have the substituent is 2 or more, the substituents may be the same or different from each other. The Z is preferably a naphthyl group having three sulfo groups as substituents, and the substitution positions are clockwise at the 3rd and 5th positions when the azo bond position of the naphthyl group is 1 position. A combination of 7 positions is particularly preferable.

In the black dye represented by the above formula (1), n represents an integer of 1 or 2, and is preferably 1.

In the black dye represented by the above formula (1), the hydroxy group and the sulfo group, or the carboxy group when having a carboxy group, may be a free acid or a salt, respectively.

Examples of the hydroxy group, sulfo group, and carboxy group salts include alkali salts such as lithium salt, sodium salt, and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt, ammonium salt, and methyl ammonium salt. Examples thereof include ammonium salts such as dimethylammonium salt, triethylammonium salt, tetraethylammonium salt, and tetra-n-propylammonium salt, which can be arbitrarily selected depending on the required performance of the ink including the free acid. For example, a combination consisting of all free acids, a combination consisting of all 1 type salt, a combination consisting of free acid and 1 type salt, a combination consisting of free acid and 2 or more types of salts, a combination consisting of 2 or more types of salts, etc. The combination ratio may be arbitrarily set in the combination of free acid and one kind of salt, the combination of free acid and two or more kinds of salts, and the combination of two or more kinds of salts.

[Brown dye]
The ink contains a brown dye. The brown dye is preferably a brown dye having an azo bond in the molecule, and more preferably a brown dye having an azo bond and a triazine skeleton in the molecule.

Examples of the brown dye having an azo bond in the molecule include Direct Red 84 and the like.

Examples of the brown dye having an azo bond and a triazine skeleton in the molecule include C.I. I. Examples thereof include Direct Brown 195, a brown dye described in Japanese Patent No. 5085129, and a brown dye described in Japanese Patent 5624051.

It is particularly preferable that the brown dye is represented by the above formula (2).

In the above formula (2), the ^{Q 8} are each independently of the ^{Q 1,} a hydrogen atom, a halogen atom, a sulfo group, a carboxy group, a sulfamoyl group, a carbamoyl group, C1-C4 alkyl group; C1-C4 alkoxy group; a hydroxy group, C1-C4 alkoxy group substituted with at least one group selected from the group consisting of C1-C4 alkoxy group, hydroxy C1-C4 alkoxy group, sulfo group, and carboxy group; C1-C4 alkylcarbonylamino group; carboxy C1-C4 alkylcarbonylamino group substituted with a group; ureido group; mono-C1-C4 alkyl ureido group; di-C1-C4 alkyl ureido group; at least one selected from the group consisting of a hydroxy group, a sulfo group, and a carboxy group. Mono-C1-C4 alkyl ureido groups substituted with different groups; di-C1-C4 alkyl ureido groups substituted with at least one group selected from the group consisting of hydroxy groups, sulfo groups, and carboxy groups; benzoylamino Group; A benzoylamino group in which the benzene ring is substituted with at least one group selected from the group consisting of a halogen atom, a C1-C4 alkyl group, a nitro group, a sulfo group, and a carboxy group; a benzenesulfonylamino group; or Represents a phenylsulfonylamino group in which the benzene ring is substituted with at least one group selected from the group consisting of halogen atoms, C1-C4 alkyl groups, nitro groups, sulfo groups, and carboxy groups.
X is a C1-C8 alkylene diamino group; a C1-C8 alkylene diamino group substituted with a hydroxy group or a carboxy group; an N- (C1-C4) alkyl- (C1-C6) alkylene diamino group; the alkyl moiety is a hydroxy group or N- (C1-C4) alkyl- (C1-C6) alkylene diamino group substituted with carboxy group; amino C1-C6 alkoxy C1-C6 alkylamino group; amino C1-C4 alkoxy C1-C4 alkoxy C1-C4 alkylamino Group; xylylene diamino group; piperazin-1,4-diyl group; piperazin-1,4-diyl group substituted with C1-C4 alkyl group or C1-C4 alkoxy group; and phenylenediamino group; Represents any group selected. The halogen atom may be the same as above.

In Q ⁸ from the Q ^1, as the C1-C4 alkyl group includes a straight chain or branched chain, a straight chain is preferred. Specific examples include linear chains such as methyl, ethyl, n-propyl and n-butyl; branched chains such as isopropyl, isobutyl, sec-butyl and t-butyl; and the like. Preferred specific examples include methyl and ethyl, with methyl being particularly preferred.

In ^{Q 8} from the ^{Q 1,} as the C1-C4 alkoxy group include a straight chain or branched chain. Specific examples include linear chains such as methoxy, ethoxy, n-propoxy, n-butoxy; and branched chains such as isopropoxy, isobutoxy, sec-butoxy, and t-butoxy; and the like. Preferred specific examples include methoxy and ethoxy, and methoxy is particularly preferable.

In ^{Q 8} from the ^{Q 1,} hydroxy group, C1-C4 alkoxy group, hydroxy C1-C4 alkoxy group, a sulfo group, and at least one C1-C4 alkoxy substituted with a group selected from the group consisting of a carboxy group Examples of the group include those having these substituents on any carbon atom in the C1-C4 alkoxy group. The number of the substituents is usually one or two, preferably one. The position of the substituent is not particularly limited, but it is preferable that the same carbon atom is not substituted with two or more oxygen atoms. Specific examples include hydroxy C1-C4 alkoxy groups such as 2-hydroxyethoxy, 2-hydroxypropoxy, and 3-hydroxypropoxy; methoxyethoxy, ethoxyethoxy, n-propoxyethoxy, isopropoxyethoxy, n-butoxyethoxy, and methoxypropoxy. , C1-C4 alkoxy C1-C4 alkoxy groups such as ethoxypropoxy, n-propoxypropoxy, isopropoxybutoxy, n-propoxybutoxy; hydroxy C1-C4 alkoxy C1-C4 alkoxy groups such as 2-hydroxyethoxyethoxy; carboxymethoxy, CarboxyC1-C4 alkoxy groups such as 2-carboxyethoxy and 3-carboxypropoxy; sulfoC1-C4 alkoxy groups such as 2-sulfoethoxy, 3-sulfopropoxy and 4-sulfobutoxy; and the like.

In Q ⁸ from the Q ^1, as the C1-C4 alkyl carbonyl amino group includes a straight chain or branched chain, a straight chain is preferred. Specific examples include linear ones such as acetylamino (methylcarbonylamino), ethylcarbonylamino, propylcarbonylamino and butylcarbonylamino; branched chains such as isopropylcarbonylamino and t-butylcarbonylamino; and the like. Be done.

In Q ⁸ from the Q ^1, Examples of the C1-C4 alkyl carbonyl amino group substituted by a carboxy group, 2-carboxyethyl carbonylamino, 3-carboxypropyl carbonyl carboxy C1-C4 alkyl carbonyl amino group such as an amino ; Etc. can be mentioned. The number of substitutions of the carboxy group is usually one or two, preferably one.

In Q ⁸ from the Q ^1, Mono-C1-C4 alkyl ureido group, the alkyl moieties are a straight chain or branched chain. The substitution position of the C1-C4 alkyl is not particularly limited, but it is preferably substituted with "N'". In the present specification, the "mono-C1-C4 alkyl ureido group" means a "C1-C4 alkyl NH-CO-NH-" group or a "H2N-CO-N (C1-C4 alkyl)-" group. In the benzene ring to which R1 and R8 are bonded, the nitrogen atom directly bonded to the benzene ring is described as "N", and the nitrogen atom bonded to the nitrogen atom via the carbonyl (CO) group is described as "N'". Therefore, the substitution position of the C1-C4 alkyl is "N'" for the former and "N" for the latter. Specific examples include linear ones such as N'-ethyl ureido, N'-propyl ureido, and N'-butyl ureide; N'-isopropyl ureido, N'-isobutyl ureido, N'-t-butyl ureido, and the like. Branched chain; etc.

In Q ⁸ from the Q ^1, as the di-C1-C4 alkyl ureido group include a straight chain or branched chain. The substitution position of the C1-C4 alkyl is not particularly limited, and one for each of "N" and "N'" or two for "N'" according to the substitution position in the above-mentioned "mono C1-C4 alkyl ureido group". The latter is preferable, although the one substituted with one is mentioned. Further, the two C1-C4 alkyls may be the same or different, but the same one is preferable. Specific examples include linear ones such as N', N'-dimethylureide, N', N'-diethylureido, N', N'-dipropylureido, N', N'-dibutylureide;N'. , N'-diisopropylureido, N', N'-diisobutylureido and the like; etc.

The mono-C1-C4 alkyl ureido group substituted with at least one group selected from the group consisting of a hydroxy group, a sulfo group, and a carboxy group in Q ¹ to Q ⁸ is the mono-C1-C4 alkyl ureido. Any carbon atom in the group includes those having these substituents. The number of the substituents is usually one or two, preferably one. The position of the substituent is not particularly limited, but it is preferable that the nitrogen atom and the hydroxy group do not substitute for the same carbon atom. Specific examples include N'-mono (hydroxy C1-C4 alkyl) ureido groups such as N'-2-hydroxyethyl ureido and N'-3-hydroxypropyl ureido; N'-2-sulfoethyl ureido, N'-. N'-mono (sulfoC1-C4 alkyl) ureido groups such as 3-sulfopropyl ureido; N'-carboxymethyl ureido, N'-2-carboxyethyl ureido, N'-3-carboxypropyl ureido, N'-4 N'-mono (carboxyC1-C4 alkyl) ureido groups such as -carboxybutyl ureido; and the like.

The di-C1-C4 alkyl ureido group substituted with at least one group selected from the group consisting of a hydroxy group, a sulfo group, and a carboxy group in Q ¹ to Q ⁸ is the di C1-C4 alkyl ureido. Any carbon atom in the group includes those having these substituents. The number of the substituents is usually one or two, preferably two. The position of the substituent is not particularly limited, but it is preferable that the nitrogen atom and the hydroxy group do not substitute for the same carbon atom. When a plurality of substituents are provided, the types may be the same or different, but the same type is preferable. Specific examples include N', N'-di (2-hydroxyethyl) ureido, N', N'-di (2-hydroxypropyl) ureido, N', N'-di (3-hydroxypropyl) ureido and the like. N', N'-di (hydroxy C1-C4 alkyl) ureido group; N', N'-di (sulfo C1-C4 alkyl) ureido group such as N', N'-di (3-sulfopropyl) ureide. N', N'-di (carboxymethyl) ureido and the like N', N'-di (carboxyC1-C4 alkyl) ureido group; and the like.

In Q ⁸ from the Q ^1, benzene ring, a halogen atom (fluorine atom, chlorine atom, bromine atom, and an iodine atom, a chlorine atom is particularly preferred.), C1-C4 alkyl group, a nitro group, a sulfo group , And the benzoylamino group substituted with at least one group selected from the group consisting of carboxy groups includes those having one to three, preferably one or two of these substituents. When a plurality of substituents are provided, the types may be the same or different, but those having the same type are preferable. Specific examples include halogen atom-substituted benzoylamino groups such as 2-chlorobenzoylamino, 4-chlorobenzoylamino, and 2,4-dichlorobenzoylamino; 2-methylbenzoylamino, 3-methylbenzoylamino, and 4-methylbenzoylamino. C1-C4 alkyl-substituted benzoylamino groups such as 2-nitrobenzoylamino, 4-nitrobenzoylamino, 3,5-dinitrobenzoylamino and other nitro-substituted benzoylamino groups; 2-sulfobenzoylamino, 4-sulfobenzoylamino and the like. Sulfo-substituted benzoylamino groups; carboxy-substituted benzoylamino groups such as 2-carboxybenzoylamino, 4-carboxybenzoylamino, 3,5-dicarboxybenzoylamino; and the like.

In Q ⁸ from the Q ^1, benzene ring, a halogen atom, C1-C4 alkyl group, a nitro group, a sulfo group, and at least one substituted phenylsulfonylamino group with a group selected from the group consisting of a carboxy group Examples thereof include those having one to three, preferably one or two, and more preferably one of these substituents. When having a plurality of substituents, the types may be the same or different. Specific examples include halogen atom-substituted phenylsulfonylamino groups such as 2-chlorophenylsulfonylamino and 4-chlorophenylsulfonylamino; 2-methylphenylsulfonylamino, 4-methylphenylsulfonylamino, 4-t-butylphenylsulfonylamino and the like. C1-C4 alkyl-substituted phenylsulfonylamino groups; nitro-substituted phenylsulfonylamino groups such as 2-nitrophenylsulfonylamino, 3-nitrophenylsulfonylamino, 4-nitrophenylsulfonylamino; 3-sulfophenylsulfonylamino, 4-sulfophenyl Sulfonyl-substituted phenylsulfonylamino groups such as sulfonylamino; carboxy-substituted phenylsulfonylamino groups such as 3-carboxyphenylsulfonylamino and 4-carboxyphenylsulfonylamino; and the like.

Of the above, the ^{Q 8} from ^{Q 1,} a hydrogen atom; a halogen atom; C1-C4 alkyl group; C1-C4 alkoxy group; a sulfo group or a C1-C4 alkoxy group substituted with carboxy group; C1-C4 alkylcarbonyl Amino group; is preferable. Among these, hydrogen atom, methyl, ethyl, t-butyl, 2-carboxyethoxy, 3-carboxypropoxy, 2-sulfoethoxy, 3-sulfopropoxy, 4-sulfobutoxy; are more preferable. Particularly preferred are hydrogen atom, methyl and 3-sulfopropoxy.

In the above formula (2), as the ^{Q 8} from ^{Q 1,} it is preferable a C1-C4 alkoxy groups at least one substituted by a sulfo group. Further, Q ¹ to Q ⁴ are independently C1-C4 alkoxy groups substituted with a hydrogen atom, a C1-C4 alkyl group, or a sulfo group, and at least one of Q ¹ to Q ⁴ is substituted with a sulfo group. has been a C1-C4 alkoxy group, ^{Q 8} are each independently of the ^{Q 5,} which are more preferably a hydrogen atom or a C1-C4 alkyl group. At least one of ^{Q 1} and ^{Q 2} are sulfopropoxy group, at least one of ^{Q 3} and ^{Q 4} are sulfopropoxy group, ^{Q 8} from ^{Q 5} and more preferably has a C1-C4 alkyl group. Further, ^one of Q ¹ and Q ² is a sulfopropoxy group, the other is a hydrogen atom or a sulfopropoxy group, one of Q ³ and Q ⁴ is a sulfopropoxy group, and the other is a hydrogen atom or a sulfopropoxy group, and Q ⁵ what Q ⁸ is a methyl group from being particularly preferred.

Is not substituted position particularly limited in Q ⁸ from the Q ^1, in each of the benzene rings to which they are substituted, position 1 the substitution position of the nitrogen atom attached to the triazine ring, a 4-position to the substitution position of the azo group, Q ^It is preferable to replace ¹ to Q ⁴ with the 2nd position and Q ⁵ to Q ⁸ with the 5th position.

X is a C1-C8 alkylene diamino group; a C1-C8 alkylene diamino group substituted with a hydroxy group or a carboxy group; an N- (C1-C4) alkyl- (C1-C6) alkylene diamino group; the alkyl moiety is a hydroxy group or N- (C1-C4) alkyl- (C1-C6) alkylene diamino group substituted with carboxy group; amino C1-C6 alkoxy C1-C6 alkylamino group; amino C1-C4 alkoxy C1-C4 alkoxy C1-C4 alkylamino Group; xylylene diamino group; piperazin-1,4-diyl group; piperazin-1,4-diyl group substituted with C1-C4 alkyl group or C1-C4 alkoxy group; and phenylenediamino group; Represents any group selected

Examples of the C1-C8 alkylene diamino group include those having a straight chain or a branched chain, and those having a straight chain are preferable. The range of carbon numbers is usually C1-C8, preferably C2-C8, more preferably C2-C6, and even more preferably C2-C4. Specific examples include ethylene diamino, 1,3-propylene diamino, 1,4-butylenediamino, 1,5-pentylene diamino, 1,6-hexylene diamino, 1,7-heptylene diamino, and 1,8. -Linear chain such as octylene diamino; branched chain such as 2-methyl-1,3-propylene diamino, 3-methyl-1,4-butylenediamino, 4-methyl-1,6-hexylene diamino ; Etc. can be mentioned.

Examples of the C1-C8 alkylene diamino group substituted with the hydroxy group or the carboxy group include those having these substituents on any carbon atom in the C1-C8 alkylene diamino group. The number of the substituents is not particularly limited, but is preferably one or two. When a plurality of substituents are provided, the types may be the same or different, but the same type is preferable. Specific examples include hydroxy-substituted C1-C8 alkylene diamino groups such as 2-hydroxy-1,3-propylene diamino, 2-hydroxy-1,4-butylenediamino, 3-hydroxy-1,6-hexylene diamino; 1 -Carboxyethylenediamino, 1-carboxy-1,3-propylenediamino, 1-carboxy-1,4-butylenediamino, 1-carboxy-1,5-pentylenediamino, 1,5-dicarboxy-1,5- Carboxy-substituted C1-C8 alkylene diamino groups such as pentylene diamino; and the like.

The N- (C1-C4) alkyl- (C1-C6) alkylene diamino group means that one nitrogen atom of the C1-C6 alkylene diamino group is replaced with a C1-C4 alkyl group. In the present specification, the nitrogen atom substituted with the C1-C4 alkyl group among the diamino groups is referred to as "N", and the other nitrogen atom is referred to as "N'" if necessary. The range of the number of carbon atoms of the alkylene moiety is usually C1-C6, preferably C2-C4, and particularly preferably C2 or C3. Examples of the C1-C4 alkyl group include those having a straight chain or a branched chain, and those having a straight chain are preferable. Specific examples include N- (linear C1-C4) alkyl- (C1-C6) alkylene such as N-methylethylenediamino group, N-ethylethylenediamino group, N-propylethylenediamino group and N-butylethylenediamino group. Diamino group; N- (branched chain C1-C4) alkyl- (C1-) such as N-isopropylethylenediamino group, N-isobutylethylenediamino group, N-sec-butylethylenediamino group, Nt-butylethylenediamino group, etc. C6) An alkylene diamino group; and the like.

The N- (C1-C4) alkyl- (C1-C6) alkylene diamino group in which the alkyl moiety is substituted with a hydroxy group or a carboxy group is the N- (C1-C4) alkyl- (C1-C6) alkylene. Examples of the diamino group include those having these substituents at any carbon atom of the alkyl portion of the N- (C1-C4) alkyl group. The position of the substituent is not particularly limited, but it is preferable that the nitrogen atom and the hydroxy group are not substituted with the same carbon atom. The range of the number of carbon atoms of the alkylene moiety includes the same range as that of the N-C1-C4 alkyl-C1-C6 alkylene diamino group, including those preferable. The carbon number range of the alkyl moiety is usually C1-C4, preferably C2-C4, and more preferably C2-C3. The number of the substituents is usually one or two, preferably one. When a plurality of substituents are provided, the types may be the same or different, but the same type is preferable. Specific examples include N- (2-hydroxyethyl) ethylenediamino group, N- (3-hydroxypropyl) ethylenediamino group, N- (2-hydroxypropyl) ethylenediamino group, N- (4-hydroxybutyl) ethylene. N-Hydroxysubstituted C1-C4 alkyl- (C1-C6) alkylene diamino group such as diamino group; N- (carboxymethyl) ethylenediamino group, N- (2-carboxyethyl) ethylenediamino group, N- (3-carboxy) Examples thereof include an N-carboxy-substituted C1-C4 alkyl- (C1-C6) alkylenediamino group such as a propyl) ethylenediamino group and an N- (4-carboxybutyl) ethylenediamino group.

Examples of the amino C1-C6 alkoxy C1-C6 alkylamino group include those having a straight chain or a branched chain, and those having a straight chain are preferable. The range of the number of carbon atoms is usually an amino C1-C6 alkoxy C1-C6 alkylamino group, preferably an amino C2-C4 alkoxy C2-C4 alkylamino group, and particularly preferably an amino C2-C3 alkoxy C2-C3 alkyl. Amino groups can be mentioned. Specific examples include aminoethoxyethylamino, aminoethoxypropylamino, aminopropoxypropylamino, aminoethoxypentylamino and the like.

Examples of the amino C1-C4 alkoxy C1-C4 alkoxy C1-C4 alkylamino group include those having a straight chain or a branched chain, and those having a straight chain are preferable. The range of the number of carbon atoms is usually an amino C1-C4 alkoxy C1-C4 alkoxy C1-C4 alkylamino group, preferably an amino C2-C4 alkoxy C2-C4 alkoxy C2-C4 alkylamino group, and particularly preferably an amino. C2-C3 alkoxy C2-C3 alkoxy C2-C3 alkylamino groups can be mentioned. Specific examples include linear ones such as aminoethoxyethoxyethylamino, aminoethoxypropoxyethylamino, aminoethoxybutoxyethylamino; aminoethoxy (2-methylethoxy) ethylamino, aminoethoxy (2-methylpropoxy) ethylamino. Such as those of branched chains; etc.

Examples of the xylylene diamino group include o-, m-, and p-xylylene diamino groups, with m- or p-xylylene diamino groups being preferred.

Examples of the piperazine-1,4-diyl group substituted with the C1-C4 alkyl group or the C1-C4 alkoxy group include those having these substituents on any carbon atom of the ring-constituting atom of the piperazine ring. Be done. The number of the substituents is usually one or two, preferably one. When a plurality of substituents are provided, the types may be the same or different, but the same type is preferable. Specific examples include 2-methylpiperazin-1,4-diyl group, 2-ethylpiperazin-1,4-diyl group, 2,5-dimethylpiperazine-1,4-diyl group, 2,6-dimethylpiperazine-. Examples thereof include 1,4-diyl group, 2,5-diethylpiperazin-1,4-diyl group, 2-methyl-5-ethylpiperazine-1,4-diyl group; and the like.

Examples of the phenylenediamino group include o-, m-, and p-phenylenediamino groups, and m- or p-phenylenediamino group is preferable.

Among the above, X is a C1-C8 alkylene diamino group; a C1-C8 alkylene diamino group substituted with a carboxy group; an N- (C1-C4) alkyl- (C1-C6) having an alkyl moiety substituted with hydroxy. Preferable examples include an alkylenediamino group; an amino C1-C4 alkoxy C1-C4 alkoxy C1-C4 alkylamino group; a xylylene diamino group; or a piperazin-1,4-diyl group; More preferably, a C2-C4 alkylene diamino group; a C2-C6 alkylene diamino group substituted with a carboxy group; an N- (C2-C3) alkyl- (C2-C3) alkylene diamino group in which the alkyl moiety is substituted with a hydroxy group. Amino C2-C3 alkoxy C2-C3 alkoxy C2-C3 alkylamino group; m- or p-xylylene diamino group; or piperazin-1,4-diyl group; More preferably, C1-C8 alkylenediamino group; xylylene diamino group; or piperazine-1,4-diyl group; can be mentioned. Of these, preferred specific examples are 1,2-ethylenediamino; 1,3-propylene diamino; 1,4-butylenediamino; 1-carboxypentylene-1,5-diamino; N-2-hydroxyethyl-. Ethylenediamino; aminoethoxyethoxyethylamino; m-xylylene diamino; or piperazine-1,4-diyl; may be mentioned.

In the above formula (2), the substitution positions of the four sulfo groups whose substitution positions are not specified are not particularly limited. The sulfo group substituted on the benzene ring having one azo bond is preferably substituted at the 2-position, 3-position, or 4-position, preferably 4-position, with the substitution position of the azo bond as the 1-position.

In the above formula (2), it is preferable that Q ^{1 to} Q ⁴ are sulfopropoxy groups, Q ^{5 to} Q ⁸ are methyl groups, and X is piperazin-1,4-diyl, respectively. It is preferable that the substitution position of each sulfo group substituted with the four benzene rings farthest from X in 2) is substituted at the para position with respect to the azo bond site of each benzene ring.

Specific examples of the brown dye represented by the above formula (2) include the compounds described in Patent Document 1.

The ink may contain a second black dye in addition to the black dye represented by the above formula (1), and both the black dye represented by the above formula (1) and the second black dye may be contained. It may further contain other black dyes having different structures.

Examples of the second black dye and the other black dye include C.I. I. Direct Black 19, 38, 168, Food Black 2, Black Dye described in Japanese Patent No. 4630584, Black Dye described in Japanese Patent No. 45333136, Black Dye described in Japanese Patent No. 45117174, Japanese Patent No. 4605635 , The black dye described in Japanese Patent No. 6218381, the black dye described in Japanese Patent Application Laid-Open No. 2017-061633, the black dye described in Japanese Patent No. 5152966, the black dye described in Japanese Patent No. 4764829. Dyes, black dyes described in Japanese Patent No. 4677403, black dyes described in Japanese Patent No. 4630584, black dyes described in Japanese Patent No. 4533136, black dyes described in Japanese Patent No. 45177174, etc. Black dye described in Japanese Patent No. 4605635, black dye described in Japanese Patent No. 6218381, black dye described in Japanese Patent Application Laid-Open No. 2017-061633, black dye described in Japanese Patent No. 5152966, Japanese Patent No. 4764829. The black dye described in Japanese Patent No. 4677403, the black dye described in Japanese Patent No. 4677403, the black dye described in Japanese Patent No. 45177174, the black dye described in Japanese Patent No. 4605635, and the black dye described in Japanese Patent No. 6218381 are described. , Black dye described in Japanese Patent Application Laid-Open No. 2017-061633, black dye described in Japanese Patent No. 5152966, black dye described in Japanese Patent No. 4764829, black dye described in Japanese Patent No. 4677403, etc. Is more preferable, and the black dye described in Japanese Patent No. 4764829, the black dye described in Japanese Patent No. 4677403, and the like are particularly preferable.

The ink may further contain a dye having another color in addition to the black dye represented by the formula (1) and the brown dye. Specific examples of such dyes include, for example, C.I. I. Yellow dyes such as Direct Yellow 34, 50, 58, 86, 132, 142, 161 and 173, and Acid Yellow 17, 23, yellow dyes described in Japanese Patent No. 5663561, yellow dyes described in WO2018-079422; C. I. Direct orange 17, 26, 29, 39, 49 and other orange dyes; C.I. I. Examples thereof include red dyes such as Direct Red 62, 75, 79, 80, 89, 225, 226, and 227. Of these, yellow dyes are preferred.

The mass% of the black dye represented by the above formula (1) in the ink is preferably 0.1% to 3.5%, more preferably 0.1% to 1.0%. Especially preferably 0.15% to 0.3%.

The mass ratio of the black dye represented by the above formula (1) to the brown dye is preferably in the range of 4: 96 to 67:33, more preferably 1: 4 to 1:20, and 1: 5. ~ 1:10 is particularly preferable.

The ink may contain at least one of a water-soluble organic solvent, a preservative, and a pH adjuster as an ink preparation agent.

Examples of the water-soluble organic solvent include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, second butanol, third butanol, 1,2-hexanediol, 1,6-hexanediol, and trimethylolpropane. C1-C6 alkanol; carboxylic acid amides such as N, N-dimethylformamide, and N, N-dimethylacetamide; lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-methylpyrrolidin-2-one. Cyclic ureas such as 1,3-dimethylimidazolidine-2-one and 1,3-dimethylhexahydropyrimido-2-one; acetone, 2-methyl-2-hydroxypentane-4-one, and Ketones or keto alcohols such as ethylene carbonate; cyclic ethers such as tetrahydrofuran and dioxane; ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,4-butylene glycol , 1,6-Hexylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol having a molecular weight of 400, 800, 1540 or more, polypropylene glycol, thiodiglycol, dithiodiglycol, etc., C2 Mono-, oligo-, and poly-alkylene glycols or thioglycols having a -C6 alkylene unit; polyols (triols) such as glycerin, diglycerin, hexane-1,2,6-triol; γ-butyrolactone; and dimethyl sulfoxide. And so on.

Examples of the preservative include organic sulfur-based, organic nitrogen-sulfur-based, organic halogen-based, haloarylsulfone-based, iodopropagil-based, haloalkylthio-based, nitrile-based, pyridine-based, 8-oxyquinolin-based, and benzothiazole-based. , Isothiazolin-based, dithiol-based, pyridine oxide-based, nitropropane-based, organic tin-based, phenol-based, tetraammonium salt-based, triazine-based, thiazine-based, anilide-based, adamantan-based, dithiocarbamate-based, brominated indanone-based, benzyl Examples thereof include bromacetate-based compounds and inorganic salt-based compounds. Moreover, 1,2-benzisothiazolin-3-one is preferably mentioned.

As the pH adjuster, any substance can be used as long as the pH of the ink can be controlled in the range of approximately 5 to 11 without adversely affecting the prepared ink. Specific examples thereof include alkanolamines such as diethanolamine, triethanolamine, N-methyldiethanolamine and triisopropanolamine; hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide. (Ammonia water); Alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium carbonate; Alkali metal salts of organic acids such as potassium acetate; Inorganic bases such as sodium silicate and disodium phosphate, etc. Can be mentioned.

The ink may further contain other additives in addition to the ink preparation agent. Examples of other additives include fungicides, chelating reagents, rust inhibitors, water-soluble ultraviolet absorbers, antioxidants, surfactants, water, and the like.

Examples of the fungicide include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof. ..

Examples of the chelating reagent include disodium ethylenediaminetetraacetate, sodium nitrilotriacetic acid, sodium hydroxyethylethylenediamine triacetate, sodium diethylenetriamine pentaacetate, and sodium uracil diacetate.

Examples of the rust preventive include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like.

Examples of the water-soluble ultraviolet absorber include sulfated benzophenone compounds, benzotriazol compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

As the antioxidant, for example, various organic and metal complex-based anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indans, alkoxyanilines, heterocyclics such as chromans, and the like. Can be mentioned.

Examples of the surfactant include known surfactants such as anion, cation, nonion, amphoteric, silicone-based, and fluorine-based. Among these, a surfactant selected from nonionic and silicone-based surfactants is preferable, and silicone-based surfactants are more preferable. Examples of anionic surfactants include alkyl sulfocarboxylic acid salts, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, N-acylamino acids or salts thereof, N-acylmethyl taurine salts, and the like. Alkyl Sulfate Polyoxyalkyl Ether Sulfate, Alkyl Sulfate Polyoxyethylene Alkether Sulfate, Loginate Soap, Himasi Oil Sulfate, Lauryl Alcohol Sulfate, Alkylphenol Phosphate, Alkyl Phosphate, Examples thereof include alkylaryl sulfonate, diethyl sulfo sulphate, diethyl hexyl sulfo sulphate, and dioctyl sulfo sulphate.

Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly4-vinylpyridine derivatives.

Examples of the nonionic surfactant include ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, and polyoxyethylene alkyl ether; Ethers such as polyoxyethylene oleic acid ester, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate; 2,4,7,9-Tetramethyl-5-decine-4,7-diol, 3,6-dimethyl-4-octin-3,6-diol, 3,5-dimethyl-1-hexin-3-ol Etc. acetylene glycol (alcohol) type; manufactured by Nissin Chemical Co., Ltd., trade name Surfinol 104, 105, 82, 465, Orphine STG, etc .; polyglycol ether type (for example, Tergitol 15-S-7 manufactured by SIGMA-ALDRICH) ); Etc. can be mentioned.

Examples of amphoteric tenside agents include betaine lauryldimethylaminoacetic acid, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, betaine palm oil fatty acid amide propyldimethylaminoacetic acid, polyoctylpolyaminoethylglycine, and imidazoline derivatives. Can be mentioned.

Examples of the silicone-based surfactant include polyether-modified siloxanes and polyether-modified polydimethylsiloxanes. As an example, Dynol 960 and Dynol 980 manufactured by Air Products Japan, Silface SAG001, Silface SAG002, Silface SAG003, Silface SAG005, Silface SAG503A, Silface SAG008, Sill made by Nisshin Kagaku Kogyo Co., Ltd. Examples thereof include Face SAG009, Silface SAG010, and BYK-345, BYK-347, BYK-348, BYK-349, and BYK-3455 manufactured by Big Chemie Japan. Among these, polyether-modified siloxanes known as the BYK series manufactured by Big Chemie Japan Co., Ltd. are preferable.

Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group as side chains. Examples thereof include a polyoxyalkylene ether polymer compound contained in. As the fluorine-based surfactant, various types of products can be easily purchased from, for example, DuPont, Omniova Solutions, DIC Corporation, Big Chemie Japan, and the like.

Each of the above inks is obtained by mixing the above components into a solution and, if necessary, filtering the solution obtained with a membrane filter or the like. As the ink for inkjet printing, it is preferable to filter the solution with a membrane filter or the like. The pore size of the membrane filter is usually 0.1 μm to 1 μm, preferably 0.1 μm to 0.5 μm.

The viscosity of each of the above inks at 25 ° C. is preferably in the range of 3 to 20 mPa · s when measured by an E-type viscometer; 20 to 40 mN / m when measured by the plate method. The viscosity of the ink can be adjusted to an appropriate value within the above range in consideration of the ejection amount of the printer; the response speed; the flight characteristics of the ink droplets; the characteristics of the inkjet head; and the like.

The present invention also includes an ink set containing the above ink and at least one of the inks selected from the group consisting of yellow ink, magenta ink, and cyan ink.

The ink set further includes any one selected from the group consisting of a second black ink, a second yellow ink, a second magenta ink, a second cyan ink, a violet ink, a green ink, and an orange ink. be able to.

A recording medium printed using the above ink and the above ink set is also included in the present invention.

The recording media are roughly classified into those having an ink receiving layer and those having no ink receiving layer. Any of these is preferable as the recording medium used in the above-mentioned inkjet recording method. Specific recording media include, for example, paper, film, fibers and cloths (cellulose, nylon, wool, etc.), leather, base materials for color filters, and the like. The ink receiving layer is installed on a recording medium for the purpose of absorbing ink and accelerating its drying. The ink receiving layer is, for example, a method of impregnating or coating the recording medium with a cationic polymer; inorganic fine particles capable of absorbing the dye in the ink are coated on the surface of the recording medium together with a hydrophilic polymer such as polyvinyl alcohol or polyvinylpyrrolidone. It is installed by the method of construction; etc. Examples of the inorganic fine particles capable of absorbing the dye in the ink include porous silica, alumina sol, and special ceramics. A recording medium having such an ink receiving layer is usually called an inkjet paper, an inkjet film, a glossy paper, a glossy film, or the like. Examples of typical commercial products of recording media having an ink receiving layer are those manufactured by Canon Corporation, trade name Professional Photo Paper, Canon Photo Paper / Glossy Pro [Platinum Grade], and Glossy Gold; manufactured by Seiko Epson Corporation, Product Name Photo Paper Crispia (High Glossy), Photo Paper (Glossy); Made by Nippon Hulett Packard Co., Ltd., Product Name Advanced Photo Paper (Glossy); Made by FUJIFILM Corporation, Product Name Color Photo Finishing Pro; Brother Industry Co., Ltd. Manufactured, trade name: photographic glossy paper BP71G; and the like. Further, as a paper having no ink receiving layer, plain paper or the like can be mentioned. Among the plain papers on the market, for inkjet recording, double-sided high-quality plain paper (manufactured by Seiko Epson Corporation); PB PAPER GF-500 (manufactured by Canon Inc.); Multipurpose Paper, All-in-one Printing Paper (manufactured by Canon Inc.) (Manufactured by Hewlett-Packard Co., Ltd.) and the like. In addition, plain paper copy (PPC) paper and the like are also plain paper.

The present invention also includes a printing method using the above ink and the above ink set.

For all the above-mentioned components and matters, the combination of preferable ones is more preferable, and the combination of more preferable ones is further preferable.

The ink containing the black dye and the brown dye represented by the above formula (1) of the present invention has a feature of having good filterability for, for example, a membrane filter, and when recorded on various recording media, it is extremely It is clear, has excellent color development and color rendering properties, and gives a black image with an ideal hue. Therefore, it is possible to faithfully reproduce a color image of photographic image quality on a recording medium. Furthermore, the ink of the present invention has extremely good storage stability without solid precipitation, physical property change, hue change, etc. after long-term storage. In addition, the ink of the present invention is extremely unlikely to precipitate solids due to drying, and therefore, the injector (recording head) of the inkjet printer is not clogged. Further, the ink of the present invention does not cause a change in physical properties in a continuous inkjet printer in which the ink is recirculated at a relatively long time interval or in an intermittent use by an on-demand inkjet printer.
An image recorded on a recording medium having an ink receiving layer using the ink of the present invention has various robustnesses such as light resistance, water resistance, moisture resistance, rubbing resistance and light resistance, and particularly good ozone resistance. is there. For this reason, the long-term storage stability of images recorded with photographic image quality is also excellent. Further, an image recorded on a recording medium having no ink receiving layer using the ink of the present invention is excellent in color development such as saturation, lightness, and print density. The ink recorded image using the black dye represented by the above formula (1) of the present invention and the ink containing the brown dye expresses an ideal black hue, and is exposed to light for a long time or in an ozone exposure environment. It is possible to maintain the hue even in. When color matching is performed by blending a plurality of dyes, the hue may change significantly before and after the fastness test, but in the ink recorded image using the above ink of the present invention, a * and b * are close to 0. It has an ideal hue, and the change in hue after the light resistance test and the ozone resistance test is small, and the ideal black color can be maintained.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples. Further, in each structural formula of the compound obtained in the examples, acidic functional groups such as sulfo groups are described in the form of free acids.

[Synthesis Example 1]
The structural formula of the compound synthesized according to the method described in Example 4 of Patent Document 2 is shown in the following formula (1-1).

[Synthesis Example 2]
The structural formula of the compound synthesized according to the method described in Example 9 of Patent Document 1 is shown in the following formula (2-1).

[Synthesis Example 3]
The structural formula of the compound synthesized according to the method described in Example 1 of Patent Document 3 is shown in the following formula (3-1).

[Synthesis Example 4]
The structural formula of the compound synthesized according to the method described in Example 8 of Patent Document 4 is shown in the following formula (3-2).

[(A) Ink preparation]
The components shown in Table 1 below were mixed to prepare a solution, and then filtered through a 0.45 μm membrane filter to obtain inks of each Example and Comparative Example. The pH of each ink was adjusted to the range of 8.0 to 9.5.

The abbreviations and the like in Table 1 have the following meanings. In addition, the numerical value of each component is a "part".
1-1: Compound represented by the above formula (1-1) 2-1: Compound represented by the above formula (2-1) 3-1: Compound represented by the above formula (3-1) 3- 2: Compound represented by the above formula (3-2) GLY: Glycerin NMP: N-Methyl-2-pyrrolidone IPA: Isopropyl alcohol BCA: Butylcarbitol TAU: Taurine EDA: Ethylenediaminetetraacetic acid disodium SF104: Surfinol 104PG -50
Further, "aq. NaOH" and "remaining portion" mean that the pH of each liquid was adjusted to 8.0 to 9.5 with a 25% aqueous sodium hydroxide solution, and then water was added to make the total amount of the liquid 100 parts. Means that. The surfinol 104PG-50 is a 50% propylene glycol solution of surfinol 104 manufactured by Nisshin Chemical Industry Co., Ltd.

[(B) Inkjet recording]
The inks of Examples and Comparative Examples were subjected to inkjet recording on the following glossy papers using an inkjet printer (manufactured by Canon Inc., trade name: PIXUS ip7230). At the time of recording, an image pattern was created so that 6 grades of 100%, 85%, 70%, 55%, 40%, and 25% densities could be obtained, and a halftone recorded material was obtained. The following test was carried out using the obtained recorded material as a test piece.
Glossy paper: Made by Canon Inc., Product name: Canon photo paper, glossy gold (GL-101).

[(C) Color development evaluation, hue evaluation]
Using a colorimeter (trade name: Spectro Eye ^RTM ) manufactured by GRETAG-MACBETH, the print density (Dk value) at 100% density gradation and a * and b * at each gradation were measured. The color measurement conditions are a density reference DIN NB, a viewing angle of 2 degrees, and a light source D65. The test results were evaluated according to the following criteria.
[Color development]
○ ・ ・ ・ Print density (Dk value) is 2.35 or more × ・ ・ ・ Print density (Dk value) is less than 2.35 [Hue]
◯ ... Satisfy −5.5 ≦ a * ≦ 5.5 and −5.5 ≦ b * ≦ 5.5 in all gradations.
Δ ・ ・ ・ 100% density gradation
-5.5 ≤ a * ≤ 5.5, -5.5 ≤ b * ≤ 5.5
Satisfies the conditions of
-5.5 ≤ a * ≤ 5.5, -5.5 ≤ b * ≤ 5.5
There are gradations that do not satisfy the above conditions.
× ... Does not satisfy −5.5 ≦ a * ≦ 5.5 and −5.5 ≦ b * ≦ 5.5 in all gradations.

[(D) Ozone resistance evaluation]
Each test piece was placed in an ozone weather meter (model OMS-H manufactured by Suga Test Instruments Co., Ltd.) and left for 24 hours at an ozone concentration of 10 ppm, a tank temperature of 23 ° C., and a humidity of 50% RH. For each test piece, L *, a *, and b * before and after the test at each gradation portion were color-measured under the same conditions as in (C) above, and the color difference ΔE was determined. For the color difference ΔE, a value rounded off to the nearest whole number was taken as an effective value. The test results were evaluated according to the following criteria.
[Ozone resistance]
◯ ・ ・ ・ ΔE is less than 20 in all gradations × ・ ・ ・ ΔE is 20 or more gradations The above ΔE (color difference) is a numerical difference ΔL *, Δa of L *, a *, b * before and after the test. It can be calculated from * and Δb * by the following formula (1).
ΔE = √ (ΔL *) ² + (Δa) ² + (Δb *) ² Calculation formula (1)

As is clear from Table 2, it was found that the inks of Examples 1 to 3 were excellent in color development, hue, and ozone resistance, and had these characteristics. On the other hand, it was found that Comparative Example 1 was inferior in color development and hue, and Comparative Example 2 was inferior in color development, hue and ozone resistance. These results show that the printed image obtained by the ink of the present invention can express a good black hue, and also has excellent ozone gas resistance required for an inkjet printed image, even after exposure to ozone gas. It can be seen that a good black hue can be maintained.

The ink of the present invention is suitable as a black ink for various types of recording such as for inkjet recording and writing instruments, and particularly for inkjet recording.

Claims (11)

An ink containing a black dye represented by the following formula (1) and a brown dye.

(In formula (1), Z represents a naphthyl group which may have a substituent. R ^{1 to} R ⁶ each independently represent a hydrogen atom or a substituent. N represents an integer of 1 or 2. .) The ink according to claim 1, wherein the brown dye is a brown dye having an azo bond in the molecule. The ink according to claim 2, wherein the brown dye further has a triazine skeleton. The ink according to any one of claims 1 to 3, wherein the brown dye is represented by the following formula (2).

(In the formula (2), the ^{Q 8} are each independently of the ^{Q 1,} a hydrogen atom, a halogen atom, a sulfo group, a carboxy group, a sulfamoyl group, a carbamoyl group, C1-C4 alkyl group; C1-C4 alkoxy group; a hydroxy group, C1-C4 alkoxy group substituted with at least one group selected from the group consisting of C1-C4 alkoxy group, hydroxy C1-C4 alkoxy group, sulfo group, and carboxy group; C1-C4 alkylcarbonylamino group; carboxy C1-C4 alkylcarbonylamino group substituted with a group; ureido group; mono-C1-C4 alkyl ureido group; di-C1-C4 alkyl ureido group; at least one selected from the group consisting of a hydroxy group, a sulfo group, and a carboxy group. Mono-C1-C4 alkyl ureido groups substituted with different groups; di-C1-C4 alkyl ureido groups substituted with at least one group selected from the group consisting of hydroxy groups, sulfo groups, and carboxy groups; benzoylamino Group; A benzoylamino group in which the benzene ring is substituted with at least one group selected from the group consisting of a halogen atom, a C1-C4 alkyl group, a nitro group, a sulfo group, and a carboxy group; a benzenesulfonylamino group; or Represents a phenylsulfonylamino group in which the benzene ring is substituted with at least one group selected from the group consisting of halogen atoms, C1-C4 alkyl groups, nitro groups, sulfo groups, and carboxy groups.
X is a C1-C8 alkylene diamino group; a C1-C8 alkylene diamino group substituted with a hydroxy group or a carboxy group; an N- (C1-C4) alkyl- (C1-C6) alkylene diamino group; the alkyl moiety is a hydroxy group or N- (C1-C4) alkyl- (C1-C6) alkylene diamino group substituted with carboxy group; amino C1-C6 alkoxy C1-C6 alkylamino group; amino C1-C4 alkoxy C1-C4 alkoxy C1-C4 alkylamino Group; xylylene diamino group; piperazin-1,4-diyl group; piperazin-1,4-diyl group substituted with C1-C4 alkyl group or C1-C4 alkoxy group; and phenylenediamino group; Represents any group selected. ) The ink according to any one of claims 1 to 4, further comprising a second black dye. The ink according to any one of claims 1 to 5, wherein the content mass% of the black dye represented by the above formula (1) in the ink is 0.1% to 3.5%. The ink according to any one of claims 1 to 6, wherein the mass ratio of the black dye represented by the above formula (1) to the brown dye is in the range of 4: 96 to 67:33. The ink according to any one of claims 1 to 7, further comprising at least one of a water-soluble organic solvent, a preservative, and a pH adjuster as an ink preparation agent. An ink set containing the ink according to any one of claims 1 to 8 and at least one ink selected from the group consisting of yellow ink, magenta ink, and cyan ink. A recording medium printed using the ink according to any one of claims 1 to 8 or the ink set according to claim 9. A printing method using the ink according to any one of claims 1 to 8 or the ink set according to claim 9.