JP2014034645A - Ink, ink cartridge and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink that is capable of recording an image at high levels in both light resistance and color development.SOLUTION: An ink contains a first colorant and a second colorant. The first colorant is a compound represented by general formula (I), the second colorant is C. I. direct yellow 132, and the content of the first colorant (mass%) with reference to the total mass of ink, is 0.7 to 3.0 times larger in a mass ratio relative to the content of the second colorant (mass%).

Description

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

  The ink jet recording method is a recording method in which an ink droplet is applied to a recording medium such as plain paper to form an image, and is rapidly spreading due to its low price and an increase in recording speed. On the other hand, a problem of the ink jet recording method is that the obtained recorded matter is inferior in image storability. In general, the recorded matter obtained by the ink jet recording method has lower image storage stability than silver salt photographs. In particular, when the recorded material is exposed to environmental gases such as light, humidity, heat, or ozone gas present in the air for a long time, the color material of the recorded material deteriorates, and the color tone of the image or fading easily occurs. There is a problem.

  Among the cyan, magenta, and yellow inks, it is difficult for the yellow ink to achieve both light fastness and color developability of the image. For this reason, there has been proposed an ink containing a yellow color material having a bisazo skeleton capable of recording an image with improved light resistance and excellent color developability (see Patent Document 1). A yellow ink containing two types of bisazo compounds has been proposed (see Patent Documents 2 and 3).

JP 2004-083903 A JP 2008-297541 A JP 2012-001603 A

  However, even with the yellow ink using the technique proposed in any of the above-mentioned patent documents, it has not been possible to record an image in which both the light resistance and the color developability required in recent years are compatible.

  Accordingly, an object of the present invention is to provide an ink capable of recording an image that is compatible at a high level of light resistance and color development. Another object of the present invention is to provide an ink cartridge and an ink jet recording method using the ink.

  The above object is achieved by the present invention described below. That is, according to the present invention, an ink containing a first color material and a second color material, wherein the first color material is a compound represented by the following general formula (I), The second coloring material is C.I. I. Direct yellow 132, the first colorant content (% by mass) based on the total mass of the ink is 0.7% by mass ratio with respect to the second colorant content (% by mass). The ink is characterized by being not less than twice and not more than 3.0 times.

（前記一般式（Ｉ）中、Ｒ₁は１価の基を表し、Ｒ₂は−ＯＲ₃又は−ＮＨＲ₄を表し（Ｒ₃及びＲ₄は水素原子又は１価の基を表す）、Ｒ₅はイオン性基を表し、Ｒ₆はアリーレン基又は２価のヘテロ環基を表し、Ｒ₇は２価の連結基を表し、ｍは０又は１を表す）

(In the general formula (I), R ₁ represents a monovalent group, R ₂ represents —OR ₃ or —NHR ₄ (R ₃ and R ₄ represent a hydrogen atom or a monovalent group), R ₅ represents an ionic group, R ₆ represents an arylene group or a divalent heterocyclic group, R ₇ represents a divalent linking group, and m represents 0 or 1.

  According to the present invention, it is possible to provide an ink capable of recording an image in which light fastness and color developability are compatible at a high level. In addition, according to the present invention, it is possible to provide an ink cartridge and an ink jet recording method using this ink.

It is sectional drawing which shows typically one Embodiment of the ink cartridge of this invention. FIG. 2 is a diagram schematically illustrating an example of an ink jet recording apparatus used in the ink jet recording method of the present invention, in which (a) is a perspective view of a main part of the ink jet recording apparatus, and (b) is a perspective view of a head cartridge.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. In the present invention, when the compound is a salt, the salt is dissociated into ions in the ink, but is expressed as “contains a salt” for convenience.

  The inventors of the present invention have made various studies focusing on the color developability of the compound represented by the general formula (I). The ink using the compound represented by the general formula (I) has a low color developability when recorded on a recording medium having no ink receiving layer such as plain paper, but has an ink receiving layer such as glossy paper. When recorded on a recording medium, excellent color developability is exhibited. For this reason, the mechanism by which color developability differs depending on the type of recording medium was examined. When hydrochloric acid is added as a proton source to an aqueous solution having a pH of about 8 prepared by dissolving the compound (coloring material) represented by the general formula (I) in water, the solubility of the coloring material rapidly decreases. Color material was deposited. On the other hand, even when potassium salt was added to this aqueous solution as a source of metal cations, the solubility of the coloring material was not significantly reduced, and the coloring material did not precipitate. From this, the present inventors have shown that the color developability of the ink using the compound represented by the general formula (I) is the solubility behavior of the compound represented by the general formula (I) in the presence of protons. And the difference in solubility behavior in the presence of metal cations. That is, immediately after the ink containing the compound represented by the general formula (I) is applied to glossy paper, the ink receiving layer contains a cationic component such as a cationic polymer, alumina, and alumina hydrate. The solubility of the compound represented by formula (I) is drastically lowered. For this reason, it was estimated that the compound represented by the general formula (I) agglomerated and fixed near the surface of the glossy paper, and the color developability increased. On the other hand, when an ink containing the compound represented by the general formula (I) is applied to plain paper, the compound represented by the general formula (I) is in contact with a metal cation such as calcium contained as a filler in the plain paper. Even so, the solubility does not change significantly. For this reason, it was presumed that the compound represented by the general formula (I) could not be fixed in the vicinity of the surface of plain paper but penetrated into the inside of the paper, resulting in a decrease in color developability.

  The inventors of the present invention coexisting the compound represented by the general formula (I) and a colorant having different solubility characteristics, thereby maintaining the color developability of the image on glossy paper while maintaining the color developability of the image on plain paper. I thought that it would be possible to improve. Therefore, when the dissolution characteristics of various colorants were investigated, C.I. I. It has been found that Direct Yellow 132 exhibits a solubility characteristic opposite to that of the compound represented by Formula (I). That is, C.I. I. Direct yellow 132 does not significantly decrease the solubility even when protons are added, but when the metal cation is added, the solubility decreases and precipitates. Further, a compound represented by formula (I), C.I. I. By including the direct yellow 132 in a predetermined ratio, it was possible to obtain an ink that can achieve both the color developability of glossy paper and the color developability of plain paper.

  Next, a compound represented by formula (I), C.I. I. The light resistance of images recorded using ink containing Direct Yellow 132 was evaluated. The light resistance of an image recorded using an ink containing the compound represented by formula (I) is excellent. I. Light resistance of an image recorded using ink containing direct yellow 132 is low. For this reason, the present inventors initially prepared a compound represented by the general formula (I), C.I. I. It has been speculated that the use of ink containing Direct Yellow 132 would significantly reduce the lightfastness of the image. However, the compound represented by the general formula (I) and C.I. I. The light resistance of images recorded using ink containing Direct Yellow 132 was only slightly reduced. This can be explained by the permeation behavior of ink when an image is recorded on glossy paper.

  As described above, the compound represented by the general formula (I) is fixed near the surface of the glossy paper. I. Direct yellow 132 is fixed inside glossy paper. Therefore, the compound represented by the general formula (I) and C.I. I. When ink coexisting with direct yellow 132 is applied to glossy paper, C.I. I. Direct yellow 132 is fixed at a position deeper than the compound represented by formula (I). For this reason, when the recorded matter is irradiated with light, after the compound represented by the general formula (I) absorbs and reflects the light, the remaining light that has weakened is C.I. I. Direct yellow 132 is reached. That is, since a part of the irradiated light is shielded by the compound represented by the general formula (I) fixed on the surface side, C.I. I. It is considered that the fading of direct yellow 132 is suppressed.

<Ink>
The ink of the present invention contains the first color material and the second color material at a specific mass ratio. The first color material is a compound represented by the general formula (I), and the second color material is C.I. I. Direct yellow 132. Hereinafter, each component constituting the ink of the present invention will be described in detail.

(First colorant: compound represented by formula (I))
The ink of the present invention contains a compound represented by the following general formula (I) as a first color material.

R ₁ in the general formula (I) represents a monovalent group. Monovalent groups include halogen atoms, alkyl groups, cycloalkyl groups, aralkyl groups, alkenyl groups, alkynyl groups, aryl groups, heterocyclic groups, cyano groups, hydroxy groups, nitro groups, and carboxy groups (may be in salt form). , Alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, alkylamino group, anilino group, acylamino group, aminocarbonylamino Group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkylsulfonylamino group, arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, Sulfonic acid group (may be salt type), alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, imide group, phosphino group, phosphinyl group, A phosphinyloxy group, a phosphinylamino group, and a silyl group can be mentioned.

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

  The alkyl group includes a substituted or unsubstituted alkyl group. As the substituted or unsubstituted alkyl group, an alkyl group having 1 to 30 carbon atoms is preferable. Examples of the substituent include the same as those mentioned as specific examples of the monovalent group described above. Among these, a hydroxy group, an alkoxy group, a cyano group, a halogen atom, a sulfonic acid group (may be a salt type), and a carboxy group (may be a salt type) are preferable. Examples of the alkyl group include methyl, ethyl, butyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, hydroxyethyl, cyanoethyl, 4-sulfobutyl, 4-carboxybutyl and the like.

  The cycloalkyl group includes a substituted or unsubstituted cycloalkyl group. As the substituted or unsubstituted cycloalkyl group, a cycloalkyl group having 5 to 30 carbon atoms is preferable. Examples of the cycloalkyl group include cyclohexyl, cyclopentyl, and 4-n-dodecylcyclohexyl.

  Aralkyl groups include substituted or unsubstituted aralkyl groups. As the substituted or unsubstituted aralkyl group, an aralkyl group having 7 to 30 carbon atoms is preferable. Examples of the aralkyl group include benzyl and 2-phenethyl.

  Alkenyl groups include linear, branched, or cyclic, substituted or unsubstituted alkenyl groups. As the substituted or unsubstituted alkenyl group, an alkenyl group having 2 to 30 carbon atoms is preferable. Examples of the alkenyl group include vinyl, allyl, prenyl, geranyl, oleyl, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl and the like.

  Alkynyl groups include substituted or unsubstituted alkynyl groups. As the substituted or unsubstituted alkynyl group, an alkynyl group having 2 to 30 carbon atoms is preferable. Examples of the alkynyl group include ethynyl and propargyl.

  The aryl group includes a substituted or unsubstituted aryl group. As the substituted or unsubstituted aryl group, an aryl group having 6 to 30 carbon atoms is preferable. Examples of the aryl group include phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecanoylaminophenyl, and the like.

  The heterocyclic group includes a monovalent group obtained by removing one hydrogen atom from a substituted or unsubstituted aromatic or non-aromatic heterocyclic compound. As the substituted or unsubstituted heterocyclic group, a 5-membered or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms is preferable. Examples of such aromatic heterocyclic groups include 2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl and the like.

  The alkoxy group includes a substituted or unsubstituted alkoxy group. As the substituted or unsubstituted alkoxy group, an alkoxy group having 1 to 30 carbon atoms is preferable. Examples of the alkoxy group include methoxy, ethoxy, isopropoxy, n-octyloxy, methoxyethoxy, hydroxyethoxy, 3-carboxypropoxy and the like.

  The aryloxy group includes a substituted or unsubstituted aryloxy group. The substituted or unsubstituted aryloxy group is preferably an aryloxy group having 6 to 30 carbon atoms. Examples of the aryloxy group include phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 2-tetradecanoylaminophenoxy and the like.

  As the silyloxy group, a silyloxy group having 3 to 20 carbon atoms is preferable. Examples of the silyloxy group include trimethylsilyloxy and t-butyldimethylsilyloxy.

  The heterocyclic oxy group includes a substituted or unsubstituted heterocyclic oxy group. As the substituted or unsubstituted heterocyclic oxy group, a heterocyclic oxy group having 2 to 30 carbon atoms is preferable. Examples of the heterocyclic oxy group include 1-phenyltetrazole-5-oxy, 2-tetrahydropyranyloxy and the like.

  As the acyloxy group, a formyloxy group, a substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, and a substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms are preferable. Examples of the acyloxy group include formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy, p-methoxyphenylcarbonyloxy and the like.

  The carbamoyloxy group includes a substituted or unsubstituted carbamoyloxy group. As the substituted or unsubstituted carbamoyloxy group, a carbamoyloxy group having 1 to 30 carbon atoms is preferable. Examples of the carbamoyloxy group include N, N-dimethylcarbamoyloxy, N, N-diethylcarbamoyloxy, morpholinocarbonyloxy, N, N-di-n-octylaminocarbonyloxy, Nn-octylcarbamoyloxy and the like. Can do.

  The alkoxycarbonyloxy group includes a substituted or unsubstituted alkoxycarbonyloxy group. The substituted or unsubstituted alkoxycarbonyloxy group is preferably an alkoxycarbonyloxy group having 2 to 30 carbon atoms. Examples of the alkoxycarbonyloxy group include methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy, n-octylcarbonyloxy and the like.

  The aryloxycarbonyloxy group includes a substituted or unsubstituted aryloxycarbonyloxy group. The substituted or unsubstituted aryloxycarbonyloxy group is preferably an aryloxycarbonyloxy group having 7 to 30 carbon atoms. Examples of the aryloxycarbonyloxy group include phenoxycarbonyloxy, p-methoxyphenoxycarbonyloxy, p- (n-hexadecyloxy) phenoxycarbonyloxy and the like.

  The alkylamino group includes a substituted or unsubstituted alkylamino group. As the substituted or unsubstituted alkylamino group, an alkylamino group having 1 to 30 carbon atoms is preferable. Examples of the alkylamino group include methylamino and dimethylamino.

  The anilino group includes a substituted or unsubstituted anilino group. As the substituted or unsubstituted anilino group, an anilino group having 6 to 30 carbon atoms is preferable. Examples of the anilino group include anilino, N-methylanilino, diphenylamino and the like.

  The acylamino group is preferably a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, or a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms. Examples of the acylamino group include formylamino, acetylamino, pivaloylamino, lauroylamino, benzoylamino, 3,4,5-tri-n-octyloxyphenylcarbonylamino and the like.

  The aminocarbonylamino group includes a substituted or unsubstituted aminocarbonylamino group. As the substituted or unsubstituted aminocarbonylamino group, an aminocarbonylamino group having 1 to 30 carbon atoms is preferable. Examples of the aminocarbonylamino group include carbamoylamino, N, N-dimethylaminocarbonylamino, N, N-diethylaminocarbonylamino, morpholinocarbonylamino and the like.

  The alkoxycarbonylamino group includes a substituted or unsubstituted alkoxycarbonylamino group. As the substituted or unsubstituted alkoxycarbonylamino group, an alkoxycarbonylamino group having 2 to 30 carbon atoms is preferable. Examples of the alkoxycarbonylamino group include methoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino, N-methyl-methoxycarbonylamino and the like.

  The aryloxycarbonylamino group includes a substituted or unsubstituted aryloxycarbonylamino group. As the substituted or unsubstituted aryloxycarbonylamino group, an aryloxycarbonylamino group having 7 to 30 carbon atoms is preferable. Examples of the aryloxycarbonylamino group include phenoxycarbonylamino, p-chlorophenoxycarbonylamino, m- (n-octyloxy) phenoxycarbonylamino and the like.

  The sulfamoylamino group includes a substituted or unsubstituted sulfamoylamino group. As the substituted or unsubstituted sulfamoylamino group, a sulfamoylamino group having 0 to 30 carbon atoms is preferable. Examples of the sulfamoylamino group include sulfamoylamino, N, N-dimethylaminosulfonylamino, N, N-octylaminosulfonylamino and the like.

  The alkylsulfonylamino group includes a substituted or unsubstituted alkylsulfonylamino group. As the substituted or unsubstituted alkylsulfonylamino group, an alkylsulfonylamino group having 1 to 30 carbon atoms is preferable. Examples of the alkylsulfonylamino group include methylsulfonylamino and butylsulfonylamino.

  The arylsulfonylamino group includes a substituted or unsubstituted arylsulfonylamino group having 6 to 30 carbon atoms. As the substituted or unsubstituted arylsulfonylamino group, an arylsulfonylamino group having 6 to 30 carbon atoms is preferable. Examples of the arylsulfonylamino group include phenylsulfonylamino, 2,3,5-trichlorophenylsulfonylamino, p-methylphenylsulfonylamino and the like.

  The alkylthio group includes a substituted or unsubstituted alkylthio group. As the substituted or unsubstituted alkylthio group, an alkylthio group having 1 to 30 carbon atoms is preferable. Examples of the alkylthio group include methylthio, ethylthio, n-hexadecylthio and the like.

  The arylthio group includes a substituted or unsubstituted arylthio group. As the substituted or unsubstituted arylthio group, an arylthio group having 6 to 30 carbon atoms is preferable. Examples of the arylthio group include phenylthio, p-chlorophenylthio, m-methoxyphenylthio and the like.

  The heterocyclic thio group includes a substituted or unsubstituted heterocyclic thio group. As the substituted or unsubstituted heterocyclic thio group, a heterocyclic thio group having 2 to 30 carbon atoms is preferable. Examples of the heterocyclic thio group include 2-benzothiazolylthio, 1-phenyltetrazol-5-ylthio and the like.

  The sulfamoyl group includes a substituted or unsubstituted sulfamoyl group. As the substituted or unsubstituted sulfamoyl group, a sulfamoyl group having 0 to 30 carbon atoms is preferable. The sulfamoyl group includes N-ethylsulfamoyl, N- (3-dodecyloxypropyl) sulfamoyl, N, N-dimethylsulfamoyl, N-acetylsulfamoyl, N-benzoylsulfamoyl, N- (N '-Phenylcarbamoyl) sulfamoyl) and the like.

  The alkylsulfinyl group includes a substituted or unsubstituted alkylsulfinyl group. As the substituted or unsubstituted alkylsulfinyl group, an alkylsulfinyl group having 1 to 30 carbon atoms is preferable. Examples of the alkylsulfinyl group include methylsulfinyl and ethylsulfinyl.

  The arylsulfinyl group includes a substituted or unsubstituted arylsulfinyl group. The substituted or unsubstituted arylsulfinyl group is preferably an arylsulfinyl group having 6 to 30 carbon atoms. Examples of the arylsulfinyl group include phenylsulfinyl and p-methylphenylsulfinyl.

  The alkylsulfonyl group includes a substituted or unsubstituted alkylsulfonyl group. As the substituted or unsubstituted alkylsulfonyl group, an alkylsulfonyl group having 1 to 30 carbon atoms is preferable. Examples of the alkylsulfonyl group include methylsulfonyl and ethylsulfonyl.

  The arylsulfonyl group includes a substituted or unsubstituted arylsulfonyl group. As the substituted or unsubstituted arylsulfonyl group, an arylsulfonyl group having 6 to 30 carbon atoms is preferable. Examples of the arylsulfonyl group include phenylsulfonyl and p-methylphenylsulfonyl.

  As the acyl group, a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, a substituted or unsubstituted group having 4 to 30 carbon atoms, A heterocyclic carbonyl group bonded to a carbonyl group at a carbon atom is preferred. Examples of the acyl group include acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzoyl, p- (n-octyloxy) phenylcarbonyl, 2-pyridylcarbonyl, 2-furylcarbonyl and the like.

  The aryloxycarbonyl group includes a substituted or unsubstituted aryloxycarbonyl group. The substituted or unsubstituted aryloxycarbonyl group is preferably an aryloxycarbonyl group having 7 to 30 carbon atoms. Examples of the aryloxycarbonyl group include phenoxycarbonyl, o-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl, p- (t-butyl) phenoxycarbonyl, and the like.

  The alkoxycarbonyl group includes a substituted or unsubstituted alkoxycarbonyl group. The substituted or unsubstituted alkoxycarbonyl group is preferably an alkoxycarbonyl group having 2 to 30 carbon atoms. Examples of the alkoxycarbonyl group include methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, n-octadecyloxycarbonyl and the like.

  The carbamoyl group includes a substituted or unsubstituted carbamoyl group. As the substituted or unsubstituted carbamoyl group, a carbamoyl group having 1 to 30 carbon atoms is preferable. Examples of the carbamoyl group include carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N, N-di-n-octylcarbamoyl, N- (methylsulfonyl) carbamoyl and the like.

  The imide group includes a substituted or unsubstituted imide group. As the substituted or unsubstituted imide group, an imide group having 4 to 30 carbon atoms is preferable. Examples of the imide group include succinimide, phthalimide, glutarimide, hexaneimide and the like.

  The phosphino group includes a substituted or unsubstituted phosphino group. As the substituted or unsubstituted phosphino group, a phosphino group having 2 to 30 carbon atoms is preferable. Examples of the phosphino group include dimethylphosphino, diphenylphosphino, methylphenoxyphosphino and the like.

  The phosphinyl group includes a substituted or unsubstituted phosphinyl group. As the substituted or unsubstituted phosphinyl group, a phosphinyl group having 2 to 30 carbon atoms is preferable. Examples of the phosphinyl group include phosphinyl, dioctyloxyphosphinyl, diethoxyphosphinyl and the like.

  The phosphinyloxy group includes a substituted or unsubstituted phosphinyloxy group. As the substituted or unsubstituted phosphinyloxy group, a phosphinyloxy group having 2 to 30 carbon atoms is preferable. Examples of the phosphinyloxy group include diphenoxyphosphinyloxy and dioctyloxyphosphinyloxy.

  The phosphinylamino group includes a substituted or unsubstituted phosphinylamino group. As the substituted or unsubstituted phosphinylamino group, a phosphinylamino group having 2 to 30 carbon atoms is preferable. Examples of the phosphinylamino group include dimethoxyphosphinylamino and dimethylaminophosphinylamino.

  The silyl group includes a substituted or unsubstituted silyl group. The substituted or unsubstituted silyl group is preferably a silyl group having 3 to 30 carbon atoms. Examples of the silyl group include trimethylsilyl, t-butyldimethylsilyl, phenyldimethylsilyl and the like.

  Of the monovalent groups described above, those having a hydrogen atom may be substituted with the above-mentioned monovalent group. Examples of such a substituent include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Specific examples thereof include methylsulfonylaminocarbonyl, p-methylphenylsulfonylaminocarbonyl, acetylaminosulfonyl, and benzoylaminosulfonyl groups.

R ₂ in the general formula (I) represents —OR ₃ or —NHR ₄ . R ₃ and R ₄ represent a hydrogen atom or a monovalent group. Examples of the monovalent group include those exemplified for the monovalent group represented by R ₁ described above, and the same groups including preferred ones. R ₂ is preferably —OH or —NH ₂ , and more preferably —NH ₂ .

R ₅ in the general formula (I) represents an ionic group. This ionic group may be in a salt form. Examples of the ionic group include a carboxy group, a sulfonic acid group, a phosphoric acid group, and a phosphonic acid group. Of these, a carboxy group is preferable. Examples of counter ions in the case of forming a salt include alkali metals; ammonia (NH ₃ ); cations such as organic ammonium. Examples of the alkali metal include lithium, sodium, and potassium. Examples of organic ammonium include alkylamines having 1 to 3 carbon atoms such as methylamine and ethylamine; 1 to 4 carbon atoms such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine. The following organic ammonium such as mono-, di- or trialkanolamines can be mentioned. In addition, when the compound represented by the general formula (I) has a monovalent group or an ionic group as a substituent, it may be in a salt form as in R ₅ .

R ₆ in the general formula (I) represents an arylene group or a divalent heterocyclic group. The arylene group represented by R ₆ includes a substituted or unsubstituted arylene group. As the substituted or unsubstituted arylene group, an arylene group having 6 to 30 carbon atoms is preferable. Examples of the substituent include those similar to those exemplified for the monovalent group represented by the aforementioned R _1. Examples of the arylene group include phenylene and naphthylene.

The divalent heterocyclic group represented by R ₆ is preferably a 5-membered ring or a 6-membered ring. These divalent hetero rings may be further condensed, and may be an aromatic hetero ring or a non-aromatic hetero ring. In general, heterocyclic groups can be classified into type I and type II. Type I heterocyclic groups are known as acidic nuclei. Examples of type I heterocyclic groups include 5-pyrazolone ring, 5-aminopyrazole ring, oxazolone ring, barbituric acid ring, pyridone ring, rhodanine ring, pyrazolidinedione ring, pyrazolopyridone ring, Meldrum acid ring Can do. Of these, a 5-pyrazolone ring and a 5-aminopyrazole ring are preferable. Type II heterocyclic groups are known as basic nuclei. Type II heterocyclic groups include pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole, indole, furan, benzofuran, thiophene, benzothiophene, pyrazole, imidazole, benzimidazole , Triazole, oxazole, benzoxazole, thiazole, benzothiazole, isothiazole, benzisothiazole, thiadiazole, isoxazole, benzisoxazole, pyrrolidine, piperidine, piperazine, imidazolidine, thiazoline and the like. Among them, an aromatic heterocyclic group is preferable, and pyridine, pyrazine, pyrimidine, pyridazine, triazine, pyrazole, imidazole, benzimidazole, triazole, thiazole, benzothiazole, isothiazole, benzisothiazole, thiadiazole are more preferable, and light resistance is improved. From the viewpoint, thiadiazole is particularly preferable. The divalent heterocyclic group may have a substituent. Examples of the substituent include those similar to those exemplified for the monovalent group represented by the aforementioned R _1.

R ₇ in the general formula (I) represents a divalent linking group, and m represents 0 or 1. When m is 0, it means that two R ₆ are bonded to each other.

Examples of the divalent linking group represented by R ₇ include alkylene groups such as methylene, ethylene, propylene, butylene and pentylene; alkenylene groups such as ethenylene and propenylene; alkynylene groups such as ethynylene and propynylene; phenylene and naphthylene A divalent heterocyclic group such as 6-chloro-1,3,5-triazine-2,4-diyl group, pyrimidine-2,4-diyl group, quinoxaline-2,3-diyl group; O -; - CO -; - NR 9 - (R 9 is a hydrogen atom, an alkyl group or an aryl group); - S -; - SO 2 -; - SO-; and thereof, and the like combinations.

Any of the alkylene group, alkenylene group, alkynylene group, arylene group, divalent heterocyclic group, alkyl group represented by R ₉ and aryl group may have a substituent. Examples of the substituent include those similar to those exemplified for the monovalent group represented by R ₁ described above. Examples of the alkyl group and aryl group represented by R ₉ include those exemplified above for the alkyl group and aryl group of the monovalent group represented by R ₁ , including the preferred ones. be able to.

R ₇ in the general formula (I) is an alkylene group having 10 or less carbon atoms, an alkenylene group having 10 or less carbon atoms, an alkynylene group having 10 or less carbon atoms, an arylene group having 6 to 10 carbon atoms, or a divalent heterocyclic ring. More preferably, it is a group, —O—, —S—, or a combination thereof. Among these, a combination of —S— and an alkylene group is particularly preferable from the viewpoint of the stability of the compound represented by the general formula (I).

The total number of carbon atoms of the divalent linking group represented by R ₇ is preferably 0 to 50, more preferably 0 to 30, and particularly preferably 0 to 10.

In the present invention, it is particularly preferable that the compound represented by the general formula (I) has the following structure. R ₂ is preferably an amino group. R ₆ is preferably a heterocyclic group, more preferably thiadiazole. R ₇ is preferably an alkylene group or an alkylene group containing a hetero atom, more preferably an alkylene group containing a hetero atom.

  When preferred examples of the compound represented by the general formula (I) are represented in the free acid form, the following exemplified compounds 1 to 29 can be mentioned. Of course, the present invention is not limited to the exemplified compounds shown below as long as it is included in the structure of the general formula (I) and the definition thereof. In the present invention, among the exemplary compounds shown below, exemplary compounds 1 to 13, 18 to 22, and 29 are preferable, and exemplary compound 2 is more preferable.

(First color material verification method)
In order to verify whether or not the first color material used in the present invention is contained in each ink, the following verification methods (1) to (3) using high performance liquid chromatography (HPLC) are applied. be able to.
(1) Peak retention time (2) Maximum absorption wavelength for peak of (1) (3) M / Z (posi), M / Z (negative) of mass spectrum for peak of (1)

The analysis conditions of high performance liquid chromatography are as follows. A liquid (ink) diluted about 1,000 times with pure water is used as a measurement sample. Then, an analysis by high performance liquid chromatography is performed under the following conditions, and a peak retention time and a peak maximum absorption wavelength are measured.
Column: SunFire C18 (Nippon Waters) 2.1mm x 150mm
-Column temperature: 40 ° C
・ Flow rate: 0.2 mL / min
PDA: 200 nm to 700 nm
Mobile phase and gradient conditions: Table 1

The analysis conditions of the mass spectrum are as shown below. About the obtained peak, a mass spectrum is measured on condition of the following, MZ detected most strongly is measured with respect to each of posi and nega.
・ Ionization method: ESI
・ Capillary voltage: 3.5 kV
-Desolvent gas: 300 ° C
-Ion source temperature: 120 ° C
·Detector:
posi; 40V 200-1500amu / 0.9sec
nega; 40V 200-1500amu / 0.9sec

  Under the above-mentioned method and conditions, the measurement was performed on the exemplified compound 2 which is a specific example of the compound represented by the general formula (I). As a result, the retention time, maximum absorption wavelength, M / Z (posi), and M / Z (negative) values obtained are shown in Table 2. For an unknown ink, measurement is performed under the same method and conditions as described above, and when the obtained measurement value corresponds to the value shown in Table 2, it can be determined that the compound used in the ink of the present invention is contained. .

(Second color material: CI Direct Yellow 132)
The second color material used together with the first color material is C.I. I. Direct yellow 132. C. I. As the direct yellow 132, a commercially available product can be used.

(Coloring material content)
The ink of the present invention is capable of recording an image in which both the light resistance and the color developability are high by including the first color material and the second color material in a specific mass ratio. In the ink of the present invention, the content (mass%) of the first color material is 0.7 times or more in terms of the mass ratio with respect to the content (mass%) of the second color material, based on the total mass of the ink. 0.0 times or less, preferably 1.0 times or more and 2.0 times or less. That is, “content of first color material (mass%)” / “content of second color material (mass%)” = 0.7 to 3.0 times, preferably 1.0 2 times or more and 2.0 times or less. When the mass ratio is less than 0.7 times, color development on plain paper cannot be obtained. On the other hand, if the above-mentioned mass ratio is more than 3.0 times, color development and light resistance in glossy paper cannot be obtained. In addition, when the mass ratio is 1.0 to 2.0, the color developability and light resistance of plain paper and glossy paper can be improved in a balanced manner.

  The content (% by mass) of the first color material in the ink is preferably 0.1% by mass or more and 10.0% by mass or less, and 1.0% by mass or more and 5.% by mass or less based on the total mass of the ink. More preferably, it is 0 mass% or less. The content (% by mass) of the second color material in the ink is preferably 0.1% by mass or more and 10.0% by mass or less, and 1.0% by mass or more based on the total mass of the ink. More preferably, it is 5.0 mass% or less. The ink of the present invention may contain a color material other than the first color material and the second color material. The total content (% by mass) of the coloring material in the ink is not particularly limited as long as it satisfies the reliability as an inkjet ink such as ejection characteristics, but is 0.1% by mass to 10.0% by mass. It is preferable that

(Alkali metal ions)
C. I. The solubility of direct yellow 132 in an aqueous medium tends to depend on the type and concentration of coexisting alkali metals. For example, the coexisting alkali metal types are lithium, sodium, and potassium in this order. I. The solubility of direct yellow 132 is reduced. By adjusting the concentration of various alkali metal ions in the ink as follows, the present inventors can control the cohesiveness of the second color material (CI Direct Yellow 132) accurately, and image It has been found that the light resistance of can be further improved.

In the present invention, the potassium ion concentration C _K (μmol / g), the sodium ion concentration C _Na (μmol / g), and the alkali metal ion concentration C _T (μmol / g) in the ink are 0.7 ≦ ( It is preferable to satisfy the relationship of C _K + C _Na ) / C _T. When the value of (C _K + C _Na ) / C _T is less than 0.7, the concentration of lithium ions or the like that enhances the solubility of the second color material increases, and the cohesiveness of the second color material tends to decrease. Become. For this reason, the light resistance of the image may be slightly lowered. The value of (C _K + C _Na ) / C _T is preferably 5.0 or less, and more preferably 2.0 or less.

In the present invention, the relationship between the potassium ion concentration C _K (μmol / g) and the sodium ion concentration C _Na (μmol / g) in the ink is 0.7 ≦ C _K / C _Na ≦ 2.0. It is preferable to satisfy. When this relationship is satisfied, the cohesiveness of the second color material is increased, and the position (depth) of the second color material fixed to the glossy paper is lower than the first color material. For this reason, the light shielding effect by the first color material can be obtained, and an image having higher light resistance can be recorded. If the value of C _K / C _Na is less than 0.7, the cohesiveness of the second color material tends to be lowered, and the light resistance of the image may be slightly lowered. On the other hand, if the value of C _K / C _Na is more than 2.0, the cohesiveness of the second color material is slightly increased, and the second color material is easily fixed near the surface of the glossy paper. For this reason, it is difficult to obtain the light shielding effect by the first color material, and the light resistance of the image may be slightly lowered.

Furthermore, the potassium ion concentration C _K (μmol / g) in the ink is preferably 90 μmol / g or less. If the potassium ion concentration C _K is more than 90 μmol / g, the potassium ion concentration tends to decrease the solubility of the second color material. For this reason, the cohesiveness of the second color material is slightly increased, and the second color material is easily fixed near the surface of the glossy paper. For this reason, it is difficult to obtain the light shielding effect by the first color material, and the light resistance of the image may be slightly lowered. The ink does not need to contain potassium ions. That is, the lower limit value of the potassium ion concentration in the ink may be 0 μmol / g.

  The concentration of various alkali metal ions in the ink may be adjusted by the type of counter ion of the ionic group of the color material and the content of the color material, and may be adjusted by a component other than the color material such as the electrolyte. Also good. The concentration (content) of alkali metal ions in the ink can be measured by a conventional method such as ion chromatography.

(Aqueous medium)
In the ink of the present invention, water or an aqueous medium that is a mixed solvent of water and a water-soluble organic solvent can be used. It is preferable to use deionized water (ion exchange water) as the water. The content (% by mass) of water in the ink is preferably 10.0% by mass or more and 90.0% by mass or less based on the total mass of the ink.

  The water-soluble organic solvent is not particularly limited as long as it is water-soluble, and alcohol, polyhydric alcohol, polyglycol, glycol ether, nitrogen-containing polar solvent, sulfur-containing polar solvent and the like can be used. The content (% by mass) of the water-soluble organic solvent in the ink is 5.0% by mass or more and 90.0% by mass or less, and further 10.0% by mass or more and 50.0% by mass or less based on the total mass of the ink. It is preferable that When the content of the water-soluble organic solvent is less than the above range, reliability such as ejection stability may not be obtained when the ink is used in an ink jet recording apparatus. Further, if the content of the water-soluble organic solvent is larger than the above range, the viscosity of the ink is increased and ink supply failure may occur.

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

(Other inks)
Further, in order to form a full-color image or the like, the ink of the present invention can be used in combination with another ink having a hue different from the ink of the present invention. Examples of the other ink include at least one ink selected from the group consisting of black ink, cyan ink, magenta ink, yellow ink, red ink, green ink, and blue ink. Further, a so-called light ink having substantially the same hue as these inks can be used in combination. The coloring material used for other inks and light inks may be a known dye or a newly synthesized dye.

<Ink cartridge>
The ink cartridge of the present invention includes ink and an ink storage unit that stores the ink. And the ink accommodated in this ink accommodating part is the ink of this invention demonstrated above. FIG. 1 is a cross-sectional view schematically showing an embodiment of the ink cartridge of the present invention. As shown in FIG. 1, an ink supply port 12 for supplying ink to the recording head is provided on the bottom surface of the ink cartridge. The inside of the ink cartridge is an ink storage portion for storing ink. The ink storage portion is composed of an ink storage chamber 14 and an absorber storage chamber 16, which communicate with each other via a communication port 18. The absorber housing chamber 16 communicates with the ink supply port 12. Liquid ink 20 is stored in the ink storage chamber 14, and absorbers 22 and 24 that hold the ink in an impregnated state are stored in the absorber storage chamber 16. The ink storage unit may have a form in which the entire amount of ink stored is held by an absorber without having an ink storage chamber for storing liquid ink. Further, the ink storage portion may have a form that does not have an absorber and stores the entire amount of ink in a liquid state. Further, the ink cartridge may be configured to have an ink storage portion and a recording head.

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

  2A and 2B are diagrams schematically showing an example of an ink jet recording apparatus used in the ink jet recording method of the present invention. FIG. 2A is a perspective view of a main part of the ink jet recording apparatus, and FIG. 2B is a perspective view of a head cartridge. It is. The ink jet recording apparatus is provided with a conveying means (not shown) for conveying the recording medium 32 and a carriage shaft 34. A head cartridge 36 can be mounted on the carriage shaft 34. The head cartridge 36 includes recording heads 38 and 40, and is configured such that an ink cartridge 42 is set. While the head cartridge 36 is conveyed along the carriage shaft 34 in the main scanning direction, ink (not shown) is ejected from the recording heads 38 and 40 toward the recording medium 32. Then, the recording medium 32 is conveyed in the sub-scanning direction by a conveying unit (not shown), whereby an image is recorded on the recording medium 32.

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

<Synthesis of coloring materials>
(Compound A)
(A)
In a solution obtained by dissolving 13.3 g of the compound represented by the following formula (1) in 100 mL of methanol, 20 mL of an aqueous solution obtained by dissolving 4.5 g of potassium hydroxide in water, and 1,2-dibromoethane 0 g was added. After refluxing for 2 hours, the precipitated crystals were filtered to obtain 13.0 g of a compound represented by the following formula (2).

(B)
A mixture of 59.8 g of the compound represented by the following formula (3), 32.0 g of pivaloyl acetonitrile, 65.0 g of sodium hydrogen carbonate, 340 mL of water, and 340 mL of ethanol was heated for 2 hours, and then 60 mL of hydrochloric acid was added. . After further heating for 2 hours, the precipitated crystals were filtered to obtain 61.0 g of a compound represented by the following formula (4).

(C)
A mixed solution of 6.0 g of the compound represented by the formula (4) obtained in the procedure (b), 80 mL of methanol, and 30 g of sodium acetate was cooled to 10 ° C. or lower. Further, 3.0 g of the compound represented by the formula (2) obtained in the procedure (a) and sodium nitrite were mixed to obtain a diazo liquid. This diazo liquid was added to the mixed liquid at 10 ° C. or lower and stirred at room temperature for 2 hours. The precipitated crystals were filtered and then purified by column chromatography using Sephadex (trade name). Further, hydrochloric acid was added to adjust the pH to 1.0 or less to obtain the free acid form of the following formula (5) Then, 4.3 g of the compound A represented by the formula:

(D)
A potassium hydroxide aqueous solution was added to the free acid type compound A obtained in the procedure (c) to adjust the pH to 8.0 to obtain a potassium salt type compound A.

(Compound B and Compound C)
Similar to the synthesis of Compound A described above except that the potassium hydroxide aqueous solution used in step (d) was changed to a sodium hydroxide aqueous solution or a lithium hydroxide aqueous solution, sodium salt type compound B and lithium A salt form of Compound C was obtained.

(Comparative Compound A)
In accordance with the method for synthesizing Exemplified Compound 5 described in Patent Document 2, Comparative Compound A represented by the following formula was synthesized.

(Comparative Compound B)
After synthesizing according to the method for synthesizing Exemplified Compound 16 described in Patent Document 2, the pH was adjusted to 7.5 using an aqueous sodium hydroxide solution to obtain Comparative Compound B represented by the following formula. It was.

<Preparation of ink>
After mixing each component (unit:%) shown in the upper part of Tables 3-1 to 3-3 and stirring sufficiently, each ink was prepared by pressure filtration with a filter having a pore size of 0.20 μm. Also, the amount of ion-exchanged water in the ink prepared using potassium acetate or sodium acetate to adjust the potassium ion concentration and sodium ion concentration in the ink to the values shown in the lower parts of Tables 3-1 to 3-3. Is expressed as a value including potassium acetate or sodium acetate. “Acetylenol E100” in Tables 3-1 to 3-3 is a trade name of a nonionic surfactant (manufactured by Kawaken Fine Chemicals). The lower part of Tables 3-1 to 3-3 shows the content (%) of the first color material and the content (%) of the second color material in the ink. The meaning of each item described in the lower part of -1 to 3-3 is as follows.
“First / second mass ratio (times)”: Mass ratio of the content of the first color material / the content of the second color material in the ink • “Potassium concentration C _k (μmol / g) ) ”: Concentration of potassium ion in ink •“ Sodium concentration C _Na (μmol / g) ”: Concentration of sodium ion in ink •“ Lithium concentration C _Li (μmol / g) ”: Lithium ion concentration in ink Metal ion concentration C _T (μmol / g) ”: alkali metal ion concentration in ink (total)
“(C _K + C _Na ) / C _T ”: Sum of potassium ion concentration C _K (μmol / g) and sodium ion concentration C _Na (μmol / g) / alkali metal ion concentration C _T (μmol / g) g) Ratio: “C _K + C _Na ”: Ratio of potassium ion concentration C _K (μmol / g) / sodium ion concentration C _Na (μmol / g) in the ink

<Evaluation>
Each ink obtained above was filled in an ink cartridge and mounted on an ink jet recording apparatus (trade name “PIXUS iP8600”, manufactured by Canon Inc.) that discharges ink from the recording head by the action of thermal energy. In this embodiment, a solid image recorded by applying 22 ng of ink to a unit area of 1/600 inch × 1/600 inch is defined as “recording duty is 100%”. Using this ink jet recording apparatus, a recorded matter in which a solid image with a recording duty changed from 0% to 150% in increments of 5% is recorded on glossy paper and plain paper in an environment of a temperature of 23 ° C. and a relative humidity of 55%. Was made. As the glossy paper, the trade name “Canon Photo Paper / Glossy Pro [Platinum Grade] PT101” (manufactured by Canon) was used. In addition, the trade name “PB PAPER” (manufactured by Canon Marketing Japan) was used as plain paper. The obtained recorded matter was dried for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%. The optical density was measured using a spectrophotometer (trade name “Spectrolino”, manufactured by Gretag Macbeth) under the conditions of light source: D50 and field of view: 2 °. In the present invention, according to the evaluation criteria of the following items, C is a level that is not acceptable, and (AA,) A, and B are acceptable levels. The evaluation results are shown in Table 4.

(Color development)
The optical density of the solid image of each recording duty in the recorded matter using glossy paper and plain paper was measured, and the color developability was evaluated from the highest value of the optical density according to the following evaluation criteria.
[Evaluation criteria for glossy paper]
AA: The optical density was 2.30 or more.
A: The optical density was 2.25 or more and less than 2.30.
B: The optical density was 2.20 or more and less than 2.25.
C: The optical density was less than 2.20.
[Evaluation criteria for plain paper]
AA: The optical density was 1.25 or more.
A: The optical density was 1.20 or more and less than 1.25.
B: The optical density was 1.15 or more and less than 1.20.
C: The optical density was less than 1.15.

(Light resistance)
The optical density of the solid image of each recording duty in the recorded matter using glossy paper was measured, and the solid image whose value was closest to 0.50 was identified (optical density before the light resistance test). This recorded matter was placed in a super xenon tester (trade name “SX-75”, manufactured by Suga Tester) and irradiated with xenon light for 100 hours at a bath temperature of 24 ° C., a relative humidity of 60%, and an irradiation intensity of 100 kilolux. Went. Thereafter, the optical density of the same solid image as before was measured (optical density after the light fastness test). From the obtained optical density before the light resistance test and the value of the optical density after the light resistance test, the residual ratio of the optical density = the optical density after the light resistance test / the optical density before the light resistance test × 100% is calculated, Light resistance was evaluated according to the following evaluation criteria.
A: The residual ratio of the optical density was 60% or more.
B: The residual ratio of the optical density was 50% or more and less than 60%.
C: The residual ratio of optical density was less than 50%.

Claims (6)

An ink containing a first color material and a second color material,
The first colorant is a compound represented by the following general formula (I):
The second color material is C.I. I. Direct yellow 132,
Based on the total mass of the ink, the content (mass%) of the first color material is 0.7 to 3.0 times the mass ratio of the content (mass%) of the second color material. Ink characterized by:

(In the general formula (I), R ₁ represents a monovalent group, R ₂ represents —OR ₃ or —NHR ₄ (R ₃ and R ₄ represent a hydrogen atom or a monovalent group), R ₅ represents an ionic group, R ₆ represents an arylene group or a divalent heterocyclic group, R ₇ represents a divalent linking group, and m represents 0 or 1. In the ink, the potassium ion concentration C _K (μmol / g), the sodium ion concentration C _Na (μmol / g), and the alkali metal ion concentration C _T (μmol / g) are 0.7 ≦ (C _K + C _Na ) / C _T ink according to claim 1 which satisfies the relation. The potassium ion concentration C _K (μmol / g) and the sodium ion concentration C _Na (μmol / g) in the ink satisfy a relationship of 0.7 ≦ C _K / C _Na ≦ 2.0. The ink according to 2. The ink according to any one of claims 1 to 3, wherein a potassium ion concentration C _K (µmol / g) in the ink is 90 µmol / g or less. An ink cartridge comprising ink and an ink containing portion for containing the ink,
The ink cartridge according to claim 1, wherein the ink is an ink according to claim 1. An inkjet recording method for recording an image on a recording medium by discharging ink from an inkjet recording head,
An ink jet recording method, wherein the ink is the ink according to claim 1.

Images