JP2005220258A - Coloring composition, ink for ink jet and ink jet recording method using those - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ink for ink jet and an ink set each containing a water-soluble dye excellent in fastness and capable of ensuring a high printing concentration and to provide an ink jet recording method. <P>SOLUTION: The coloring composition comprises a dye in which at least oxidation potential is nobler than 1.0 V (vs SCE) and an aqueous medium and in the coloring composition, the absolute value of the difference between λmax (D1) of dye in solution spectrum measurement of the coloring composition and λmax (D2) of dye in a reflection density (0.9-1.1) measured after recording the coloring composition in a reflection type medium is <14 nm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a colored composition, an ink jet ink, and an ink jet recording method using the same, and more particularly, to an ink jet black ink having high durability and image density using an azo dye made of a heterocyclic ring as a raw material.

  In recent years, a material for forming a color image has been mainly used as an image recording material, and specifically, an ink jet recording material, a thermal transfer recording material, an electrophotographic recording material, a transfer halogen. Silver halide photosensitive materials, printing inks, recording pens and the like are actively used. Further, a color filter is used for recording and reproducing a color image in an imaging device such as a CCD in a photographing apparatus and in an LCD or PDP in a display. In these color image recording materials and color filters, black colorants (dyes and pigments) are used in addition to the so-called additive color mixing method and subtractive color mixing method in order to reproduce or record full color images.

In particular, with the spread of computers, inkjet printers are widely used for printing on paper, film, cloth, etc. not only in offices but also at home.
Ink jet recording methods include a method of ejecting droplets by applying pressure with a piezo element, a method of ejecting droplets by generating bubbles in ink by heat, a method of using ultrasonic waves, or a droplet by electrostatic force. There is a method of sucking and discharging. As these ink-jet ink compositions, water-based inks, oil-based inks, or solid (melting type) inks are used. Among these inks, water-based inks are mainly used from the viewpoints of production, handleability, odor, safety, and the like.

The colorants used in these ink-jet inks have high solubility in solvents, high density recording, good hue, fastness to light, heat, air, water and chemicals. It is required to be excellent in fixability, good fixability to the image receiving material and difficult to bleed, excellent storability as ink, no toxicity, high purity, and available at low cost. Has been. However, it is extremely difficult to search for colorants that meet these requirements at a high level.
Various dyes and pigments have already been proposed and actually used for inkjet, but no colorant that satisfies all the requirements has yet been discovered. Conventionally well-known dyes and pigments to which color index (CI) numbers are assigned are difficult to achieve both the hue and fastness required for inkjet inks.

As black dyes for inkjet, food black dyes, naphthol direct azo dyes, acidic azo dyes, and the like have been widely known.
Examples of food black dyes include C.I. I. Food Black 1, C.I. I. Food Black 2 is a representative example, and techniques for using these for black ink for inkjet are described in Patent Document 1, Patent Document 2, Patent Document 3, and the like.
Examples of acidic azo dyes include C.I. I. Techniques using Acid Black 2, 31, 52, 140, 187, etc. for black ink for ink jet are disclosed in Patent Document 4, Patent Document 5, Patent Document 6, etc., and direct azo dyes include C.I. I. Japanese Patent Application Laid-Open Publication No. 2003-151867 discloses a technique that uses Direct Black 9, 17, 38, 51, 60, 102, 107, 122, 142, 154, 168, etc. for inkjet black ink. It is described in Document 8, Patent Document 9, and the like.
Usually, it is difficult to cover the black hue alone, and it is preferable to use a short-wave dye together.
As this short wave dye, direct azo dyes, acidic azo dyes and the like are also widely known, and C.I. I. Acid Yellow 17, 23, 49, 194, etc., or C.I. I. Techniques using Direct Yellow 86, 120, 132, 144, and the like for inkjet black ink are described in Patent Document 10, Patent Document 11, Patent Document 12, Patent Document 13, and the like.
There is Patent Document 14 regarding λmax, but there is no description of black ink. An azo dye having an aromatic group and a heterocyclic group includes, for example, T4 described in Patent Document 15, but the oxidation potential is not nobler than 1.0 V (vs SCE). In addition to these documents, there is no document describing the difference between λmax (D1) and λmax (D2) described in the present application.
The dye of the present invention is more excellent in fastness than those described above, and a technique for using the dye of the present invention as a black ink for inkjet is described in Patent Document 16 and Japanese Patent Application No. 2003-360370.

  The inventors of the present invention have so far studied about a fast dye and have developed an excellent ink jet colorant. However, it has been found that a water-soluble dye having excellent fastness has a problem that the concentration is not easily obtained.

JP-A-2-36276 JP-A-2-233382 JP-A-2-233378 JP 60-108481 A JP-A-2-36277 JP-A-2-36278 JP-A-56-139568 JP-A 61-285275 JP-A-3-106974 Japanese Unexamined Patent Publication No. 7-97541 International Publication No. 97/16496 Japanese Patent Laid-Open No. 10-158560 Japanese Patent Laid-Open No. 11-12514 JP-A-2002-371215 Japanese Patent Laid-Open No. 2001-302952 JP 2003-306623 A

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the object of the present invention is to provide a colored image or coloring material excellent in hue and fastness, and is used for printing ink such as inkjet, ink sheet in heat-sensitive recording material, color toner for electrophotography, LCD, PDP, etc. An object of the present invention is to provide a coloring composition that can be preferably used for preparing a color filter used in an image pickup device such as a display and a CCD, and a dyeing solution for dyeing various fibers. Another object of the present invention is to provide a coloring composition, an ink jet ink, an ink set and an ink jet recording method which are water-soluble dyes having excellent fastness and can ensure a high printing density.

The object of the present invention has been achieved by the following coloring composition, ink jet ink, and ink jet recording method using them.
1) A coloring composition containing a dye having an oxidation potential of at least no less than 1.0 V (vs SCE) and an aqueous medium, wherein the dye has a λmax (D1) of the dye in the solution spectrum measurement of the coloring composition And the absolute value of the difference between λmax (D2) of the dye at a reflection density (0.9 to 1.1) measured after recording the colored composition on a reflective medium, Coloring composition.
2) The dye according to the above 1, wherein the dye contains an aromatic group and a heterocyclic group, and contains at least one dye having a half-value width of 100 nm or more in an absorption spectrum of a diluted solution normalized to an absorbance of 1.0. ) The coloring composition as described.
3) The coloring composition according to 1) or 2) above, wherein the dye has a λmax of 500 nm to 700 nm.
4) The colored composition as described in any one of 1) to 3) above, wherein the dye is a dye represented by the following general formula (1).

In the formula, A, B and C each independently represent an optionally substituted aromatic group or heterocyclic group.
5) The colored composition as described in any one of 1) to 4) above, wherein the substituent A in the dye represented by the general formula (1) is represented by the following general formula (2).

Z represents an atomic group capable of forming an aromatic ring or an aromatic heterocyclic ring. X is a substituent capable of imparting water solubility, and at least one of the substituents is substituted with a ring directly bonded to the azo group. n is an integer of 1 or more.
6) A colored composition comprising an aqueous medium containing at least one dye having an absorption spectrum λmax of 350 nm to 500 nm in an aqueous solution and at least one dye described in any one of 1) to 5) above.
7) An ink-jet ink comprising the colored composition according to any one of 1) to 6) above.
8) Image recording with an ink jet printer using the colored composition according to any one of 1) to 6), the ink for ink jet according to 7), or the ink composition containing the color composition or the ink for ink jet. An ink jet recording method comprising:

  The coloring composition of the present invention or the black ink for ink jet has a small hue difference due to the image receiving sheet, and can form an image having high fastness against light and an active gas in the environment, particularly ozone gas. Further, by using a dye in which the substituent X shown in the general formula (2) is substituted at the meta position with respect to the azo group linking portion, excellent fastness and high printing density can be secured.

  The dye used in the coloring composition of the present invention has an oxidation potential (Eox) nobler than 1.0 V (vs SCE), preferably nobler than 1.1 V (vs SCE), most preferably 1.15 V (vs SCE). It is a dye having excellent fastness due to its nobility.

  The oxidation potential value (Eox) of the dye used in the present invention can be easily measured by those skilled in the art. Regarding this method, see, for example, P.I. Delahay, “New Instrumental Methods in Electrochemistry” (published by Interscience Publishers, 1954) J. et al. "Electrochemical Methods" by Bard et al. (Published by John Wiley & Sons in 1980) and "Electrochemical Measurement Method" by Akira Fujishima et al. (Published by Gihodo Publishing Co., Ltd. in 1984).

Specifically, the oxidation potential is 1 × 10 ⁻² to 1 × 10 ⁻⁶ mol / min in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate. Dissolve in 1 liter and measure as a value relative to SCE (standard saturated calomel electrode) using cyclic voltammetry or the like. Although this value may be deviated by several tens of mil volts due to the influence of the liquid potential difference or the liquid resistance of the sample solution, the reproducibility of the potential can be ensured by inserting a standard sample (for example, hydroquinone).
In order to uniquely define the potential, in the present invention, the measurement was performed in dimethylformamide containing 0.1 mol / liter of tetrapropylammonium perchlorate as a supporting electrolyte (the concentration of the dye was 0.001 mol / liter). The value obtained (vs SCE) is taken as the oxidation potential of the dye.

The dye used in the present invention includes the dye λmax (D1) in the solution spectrum measurement of the colored composition and the reflection density (0.9 to 1.1) measured after recording the colored composition on a reflective medium. The absolute value of the difference from λmax (D2) of the dye at is less than 14 nm.
The dye of the coloring composition exhibits a dye state close to a so-called monomolecular dispersion in a solution, and λmax of the dye in the spectrum measurement at that time is defined as D1. It is presumed that the dye forms an association state by recording the coloring composition on the reflection type medium. At this time, λmax of the dye at the measured reflection density (0.9 to 1.1) is set to D2. In general, as dye association proceeds, a decrease in absorbance is observed as the absorption spectrum becomes shorter (sometimes longer), and it is expected to lead to a decrease in printing density. It is estimated that the smaller the absolute value of the difference between D1 and D2 (denoted as ΔD), the higher the print density. In the present invention, it is preferable to use at least one dye having a ΔD of less than 14 nm, preferably 10 nm or less.
The dye used in the colored composition of the present invention contains an aromatic group and a heterocyclic group, and has a half-value width (W _{λ, 1/2} ) in an absorption spectrum of a dilute solution normalized to an absorbance of 1.0 or more. It is preferable to contain at least one kind of dye. The half width is more preferably 120 nm to 500 nm, and particularly preferably 120 nm to 350 nm.
In addition, the dye used in the coloring composition of the present invention preferably has a λmax of 500 nm to 700 nm. Such dyes are optimal for black dyes.
Among the dyes defined in the above 1) to 3) of the present invention, those having the dye structure represented by 4) have a small absorption difference (ΔD) between the solution state and the printing state, and fastness. Has an excellent effect.

Of the colored composition or ink-jet ink of the present invention, as described above, the half-value width (W _{λ, 1/2} ) in the absorption spectrum of a dilute solution having a λmax of 500 nm to 700 nm and an absorbance of 1.0 is normalized. The dye having a size of 100 nm or more is a black dye (hereinafter also referred to as a dye (L)).
The spectrum measurement here will be described in detail.
The dilute solution refers to a solution having a concentration that allows the solution spectrum to be measured under normal conditions using a spectrophotometer. That is, when a cell having an optical path length of 1 cm, which is normally used, is used, this represents a solution whose absorbance (Abs) is 1.0 in the λmax part.

  The black coloring composition of the present invention is a dye (L) alone, and has high image quality. “(Good) black = not depending on the observation light source, and any color tone of B, G, R is difficult to be emphasized. When “black” can be realized, this dye can be used alone as a black dye, but it is generally used in combination with a dye that covers a region where the absorption of the dye is low. Usually, it is preferable to use together with a dye (S) having main absorption in the yellow region. Further, it is possible to prepare a black coloring composition by using it in combination with other dyes.

  In the present invention, a black colored composition is prepared by incorporating the dye into an aqueous medium alone or in combination, and it is preferable for the colored composition, that is, 1) excellent weather resistance, and / or Or 2) In order to satisfy that the black balance is not lost even after fading, it is preferable that the following conditions 1 to 3 are satisfied.

First, a black square symbol of JIS code 2223 is printed at 48 points using the colored composition, and the reflection density (Dvis) measured by the status A filter (visual filter) is defined as the initial density. An example of a reflection density measuring machine equipped with a status A filter is an X-Rite density measuring machine. Here, when measuring the density of “black”, the measured value by Dvis is used as the standard observation reflection density. This print is forcibly faded using an ozone fading tester capable of constantly generating 5 ppm of ozone, and forced from the time (t) until the reflection density (Dvis) reaches 80% of the initial reflection density value. The fading rate constant (kvis) is obtained from the relational expression “0.8 = exp (−kvis · t)”.
In the present invention, the rate constant (kvis) is 5.0 × 10 ⁻² [hour ⁻¹ ] or less, preferably 3.0 × 10 ⁻² [hour ⁻¹ ] or less, and more preferably 1.0 × 10 ^−2. [Hour ^-1 ] A coloring composition having the following ^value is preferable. (Condition 1)

  Also, the black square symbol of the JIS code 2223 is printed at 48 points using the coloring composition, and this is a density measurement value measured by a status A filter, and is not Dvis C (cyan), M (magenta), Y The reflection density (DR, DG, DB) of (yellow) three colors is also defined as the initial density. Here, (DR, DG, DB) indicates (C reflection density by the red filter, M reflection density by the green filter, and Y reflection density by the blue filter). This print is forcibly faded using an ozone fading tester capable of always generating 5 ppm of ozone according to the above method until each reflection density (DR, DG, DB) reaches 80% of the initial density value. Similarly, the forced fading rate constants (kR, kG, kB) are determined from the above time. When the three rate constants are obtained and the ratio (R) between the maximum value and the minimum value is obtained (for example, when kR is the maximum value and kG is the minimum value, R = kR / kG), the ratio ( A colored composition is preferred in which R) is 1.2 or less, preferably 1.1 or less, more preferably 1.05 or less. (Condition 2)

  Note that the “printed matter in which the black square symbol of the JIS code 2223 is printed at 48 points” used above gives an image large enough to cover the aperture of the measuring instrument in order to give a sufficient size for density measurement. It is printed.

  Furthermore, examples of the colored composition of the present invention include those prepared using the azo dye described in the general formula (1). The azo dye described in the general formula (1) first corresponds to a dye (L) having a λmax of 500 nm to 700 nm and a half-value width of 100 nm or more in an absorption spectrum of a diluted solution normalized to an absorbance of 1.0. Things can be mentioned. In addition to this, a dye (S) having a λmax of 350 nm to 500 nm can also be cited as corresponding to the dye of the general formula (1). Preferably, at least one of the dyes (L) is a dye of the general formula (1), particularly preferably at least one of the dyes (L) and (S) is a dye of the general formula (1), It is preferable that 90% by mass of the total dye in the coloring composition is the dye of the general formula (1). (Condition 3)

The spectrum measurement here will be described in detail.
The dilute solution has the same meaning as described above.
The dye of the present invention is measured with an aqueous solvent. An aqueous dye solution is preferred. As the measurement conditions, the dye is dissolved as it is in ion-exchanged water or ultrapure water.
Moreover, the inkjet ink containing dye (L) among coloring compositions is also called "black ink of this invention."

  Next, among the dyes represented by the general formula (1), those corresponding to the dye (L) will be described in detail.

  In the formula, A, B and C each independently represent an optionally substituted aromatic group or heterocyclic group. A and C are monovalent groups, and B is a divalent group.

   At least two of A, B and C are preferably an optionally substituted unsaturated heterocyclic group, and among them, particularly preferred is a case where at least B and C are an unsaturated heterocyclic group. .

  The azo dye represented by the general formula (1) is particularly preferably a dye represented by the following general formula (3).

In the general formula (3), A and B have the same meaning as in the general formula (1). B ₁ and B ₂ each represent = CR ₁ -and -CR ₂ =, or either one represents a nitrogen atom and the other represents = CR ₁ -or -CR ₂ =.
G, R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, aliphatic group, aromatic group, heterocyclic group, cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, Heterocyclic oxycarbonyl group, acyl group, hydroxy group, alkoxy group, aryloxy group, heterocyclic oxy group, silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group (alkylamino) Group, arylamino group, and heterocyclic amino group), acylamino group, ureido group, sulfamoylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkyl or arylsulfonylamino group, heterocyclic sulfonylamino group, Represents a nitro group, an alkyl or arylthio group, a heterocyclic thio group, an alkyl or arylsulfonyl group, a heterocyclic sulfonyl group, an alkyl or arylsulfinyl group, a heterocyclic sulfinyl group, a sulfamoyl group, or a sulfo group, each group being further substituted May be.
R ₅ and R ₆ are each independently a hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkyl or arylsulfonyl group, or sulfamoyl group. Each group may further have a substituent. However, R ₅ and R ₆ are not simultaneously hydrogen atoms.
R ₁ and R ₅ , or R ₅ and R ₆ may be bonded to form a 5- to 6-membered ring.
The azo dye represented by the general formula (3) is preferably a dye represented by the following general formula (4).

In the general formula (4), R ₇ and R ₈ have the same meaning as R _{1 in the} general formula (3).

  Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. An aliphatic group means an alkyl group, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an alkynyl group, a substituted alkynyl group, an aralkyl group, and a substituted aralkyl group. The aliphatic group may have a branch and may form a ring. The number of carbon atoms in the aliphatic group is preferably 1-20, and more preferably 1-16. The aryl part of the aralkyl group and the substituted aralkyl group is preferably phenyl or naphthyl, particularly preferably phenyl. Examples of aliphatic groups include methyl, ethyl, butyl, isopropyl, t-butyl, hydroxyethyl, methoxyethyl, cyanoethyl, trifluoromethyl, 3-sulfopropyl, 4-sulfobutyl, cyclohexyl group, benzyl group, 2-phenethyl Groups, vinyl groups, and allyl groups.

  The monovalent aromatic group means an aryl group and a substituted aryl group. The aryl group is preferably phenyl or naphthyl, particularly preferably phenyl. The monovalent aromatic group preferably has 6 to 20 carbon atoms, more preferably 6 to 16. Examples of the monovalent aromatic group include phenyl, p-tolyl, p-methoxyphenyl, o-chlorophenyl and m- (3-sulfopropylamino) phenyl. The divalent aromatic group is a divalent version of these monovalent aromatic groups. Examples thereof include phenylene, p-tolylene, p-methoxyphenylene, o-chlorophenylene, and m- (3- Sulfopropylamino) phenylene, naphthylene, and the like.

  The heterocyclic group includes a heterocyclic group having a substituent and an unsubstituted heterocyclic group. The heterocyclic ring may be condensed with an aliphatic ring, an aromatic ring or another heterocyclic ring. The heterocyclic group is preferably a 5-membered or 6-membered heterocyclic group, and N, O, and S can be exemplified as the hetero atom of the heterocyclic ring. Examples of the substituent include aliphatic groups, halogen atoms, alkyl and arylsulfonyl groups, acyl groups, acylamino groups, sulfamoyl groups, carbamoyl groups, ionic hydrophilic groups, and the like. Examples of heterocyclic rings used for monovalent and divalent heterocyclic groups include pyridine, thiophene, thiazole, benzothiazole, benzoxazole, and furan ring.

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

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

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

The heterocyclic oxycarbonyl group includes a substituted heterocyclic oxycarbonyl group and an unsubstituted heterocyclic oxycarbonyl group. The heterocyclic oxycarbonyl group is preferably a heterocyclic oxycarbonyl group having 2 to 20 carbon atoms. Examples of the substituent include an ionic hydrophilic group. Examples of the heterocyclic oxycarbonyl group include a 2-pyridyloxycarbonyl group.
The acyl group includes an acyl group having a substituent and an unsubstituted acyl group. The acyl group is preferably an acyl group having 1 to 20 carbon atoms. Examples of the substituent include an ionic hydrophilic group. Examples of the acyl group include an acetyl group and a benzoyl group.

  The alkoxy group includes an alkoxy group having a substituent and an unsubstituted alkoxy group. As an alkoxy group, a C1-C20 alkoxy group is preferable. Examples of the substituent include an alkoxy group, a hydroxyl group, and an ionic hydrophilic group. Examples of the alkoxy group include a methoxy group, an ethoxy group, an isopropoxy group, a methoxyethoxy group, a hydroxyethoxy group, and a 3-carboxypropoxy group.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  The heterocyclic sulfonyl group includes a heterocyclic sulfonyl group having a substituent and an unsubstituted heterocyclic sulfonyl group. As the heterocyclic sulfonyl group, a heterocyclic sulfonyl group having 1 to 20 carbon atoms is preferable. Examples of the substituent include an ionic hydrophilic group. Examples of the heterocyclic sulfonyl group include a 2-thiophenesulfonyl group and a 3-pyridinesulfonyl group.

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

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

  The alkyl and arylsulfonyl groups include substituted alkyl and arylsulfonyl groups, unsubstituted alkyl and arylsulfonyl groups. Examples of alkyl and arylsulfonyl groups include methylsulfonyl and phenylsulfonyl groups, respectively.

  Alkyl and arylsulfinyl groups include substituted alkyl and arylsulfinyl groups, unsubstituted alkyl and arylsulfinyl groups. Examples of alkyl and arylsulfinyl groups include methylsulfinyl group and phenylsulfinyl group, respectively.

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

  In the azo dye represented by the general formula (1), the substituent A is particularly preferably represented by the following general formula (2).

Z represents an atomic group capable of forming an aromatic ring or an aromatic heterocyclic ring. Xn is a substituent capable of imparting water solubility, and at least one is substituted with a ring directly bonded to the azo group. n is an integer of 1 or more.
Examples of the ionic hydrophilic group as a substituent capable of imparting water solubility include a sulfo group, a carboxyl group, a phosphono group, and a quaternary ammonium group. As the ionic hydrophilic group, a carboxyl group, a phosphono group, and a sulfo group are preferable, and a carboxyl group and a sulfo group are particularly preferable. The carboxyl group, phosphono group, and sulfo group may be in the form of a salt. Examples of counter ions that form a salt include ammonium ions, alkali metal ions (eg, lithium ions, sodium ions, potassium ions), and organic cations. (Eg, tetramethylammonium ion, tetramethylguanidinium ion, tetramethylphosphonium).
X is particularly preferably substituted at the meta position with respect to the azo group linking moiety, and the presence of this specific substitution position suppresses dye association after printing on the image receiving paper, and is a water-soluble solution with excellent fastness properties. It is considered that a high printing density can be ensured with a neutral dye.

Next, general formulas (1), (3) and (4) will be described.
In the following description, what has already been described applies to the group and the substituent.
In the general formula (1), A, B, and C are each independently an optionally substituted aromatic group (A and C are monovalent aromatic groups such as aryl groups; B is a divalent aromatic group) A group such as an arylene group) or an optionally substituted heterocyclic group (A and C are monovalent heterocyclic groups; B is a divalent heterocyclic group). Examples of the aromatic ring include a benzene ring and a naphthalene ring, and examples of the hetero atom of the heterocyclic ring include N, O, and S. The heterocyclic ring may be condensed with an aliphatic ring, an aromatic ring or another heterocyclic ring.
The substituent may be an arylazo group or a heterocyclic azo group.
Moreover, at least two of A, B, and C are preferably heterocyclic groups.

  A preferable heterocyclic group for C includes an aromatic nitrogen-containing 6-membered heterocyclic group represented by the following general formula (5). When C is an aromatic nitrogen-containing 6-membered heterocyclic group represented by the following general formula (5), the general formula (1) corresponds to the general formula (3).

In the general formula (5), B ₁ and B ₂ each represent = CR ₁ -and -CR ₂ =, or either one represents a nitrogen atom and the other represents = CR ₁ -or -CR ₂ =. More preferably, each represents = CR _1- , -CR ₂ =.
R ₅ and R ₆ are each independently a hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkyl or arylsulfonyl group, sulfamoyl group. Each group may further have a substituent. Preferable substituents represented by R ₅ and R ₆ include a hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, alkyl or arylsulfonyl group. More preferably, they are a hydrogen atom, an aromatic group, a heterocyclic group, an acyl group, an alkyl or arylsulfonyl group. Most preferably, they are a hydrogen atom, an aryl group, and a heterocyclic group. Each group may further have a substituent. However, R ₅ and R ₆ are not simultaneously hydrogen atoms.

G, R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, aliphatic group, aromatic group, heterocyclic group, cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, Heterocyclic oxycarbonyl group, acyl group, hydroxy group, alkoxy group, aryloxy group, heterocyclic oxy group, silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group (alkylamino) Group, arylamino group, and heterocyclic amino group), acylamino group, ureido group, sulfamoylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkyl or arylsulfonylamino group, heterocyclic sulfonylamino group, Nitro Represents an alkyl and arylthio group, a heterocyclic thio group, an alkyl and arylsulfonyl group, a heterocyclic sulfonyl group, an alkyl and arylsulfinyl group, a heterocyclic sulfinyl group, a sulfamoyl group, or a sulfo group, each group being further substituted Also good.

  Examples of the substituent represented by G include a hydrogen atom, a halogen atom, an aliphatic group, an aromatic group, a hydroxy group, an alkoxy group, an aryloxy group, an acyloxy group, a heterocyclic oxy group, an amino group (an alkylamino group, an aryl group). Amino group, heterocyclic amino group), acylamino group, ureido group, sulfamoylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkyl and arylthio group, or heterocyclic thio group, more preferably A hydrogen atom, a halogen atom, an alkyl group, a hydroxy group, an alkoxy group, an aryloxy group, an acyloxy group, an amino group (including an alkylamino group, an arylamino group, a heterocyclic amino group) or an acylamino group, including a hydrogen atom, Anilino group and acylamino group are most preferred.Each group may further have a substituent.

Preferable substituents represented by R ₁ and R ₂ include a hydrogen atom, an alkyl group, a halogen atom, an alkoxycarbonyl group, a carboxyl group, a carbamoyl group, a hydroxy group, an alkoxy group, and a cyano group. Each group may further have a substituent.
R ₁ and R ₅ , or R ₅ and R ₆ may combine to form a 5- to 6-membered ring.
Examples of the substituent in the case where each substituent represented by A, R ₁ , R ₂ , R ₅ , R ₆ , and G further has a substituent include the substituents exemplified for G, R ₁ , and R ₂ above. be able to. Moreover, it is preferable to further have an ionic hydrophilic group as a substituent at any position on A, R ₁ , R ₂ , R ₅ , R ₆ and G.
Examples of the ionic hydrophilic group as a substituent include a sulfo group, a carboxyl group, a phosphono group, and a quaternary ammonium group. As the ionic hydrophilic group, a carboxyl group, a phosphono group, and a sulfo group are preferable, and a carboxyl group and a sulfo group are particularly preferable. The carboxyl group, phosphono group, and sulfo group may be in the form of a salt. Examples of counter ions that form a salt include ammonium ions, alkali metal ions (eg, lithium ions, sodium ions, potassium ions), and organic cations. (Eg, tetramethylammonium ion, tetramethylguanidinium ion, tetramethylphosphonium).

  Preferred heterocycles when B is a ring structure include thiophene rings, thiazole rings, imidazole rings, benzothiazole rings, and thienothiazole rings. Each heterocyclic group may further have a substituent. Of these, thiophene rings, thiazole rings, imidazole rings, benzothiazole rings, and thienothiazole rings represented by the following general formulas (a) to (e) are preferable. In addition, when B is the thiophene ring represented by (a) and C is the structure represented by the general formula (5), the general formula (1) corresponds to the general formula (4). Become.

In the general formulas (a) to (e), R ₉ to R ₁₇ represent a substituent having the same meaning as G, R ₁ and R ₂ in the general formula (3).

  Here, Hammett's substituent constant σp value used in this specification will be described. Hammett's rule was found in 1935 by L. L. in order to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives. P. A rule of thumb proposed by Hammett, which is widely accepted today. Substituent constants determined by Hammett's rule include a σp value and a σm value, and these values can be found in many general books. A. Dean, “Lange's Handbook of Chemistry”, 12th edition, 1979 (McGraw-Hill), “Chemicals” special edition, 122, 96-103, 1979 (Nankodo). In the present invention, each substituent is limited or explained by Hammett's substituent constant σp, which means that it can be found in the above-mentioned book and is limited only to a substituent having a known value in the literature. However, it goes without saying that even if the value is unknown, it also includes a substituent that would be included in the range when measured based on Hammett's rule. In addition, the general formula (1) or (2) of the present invention includes those that are not benzene derivatives, but the σp value is used as a scale indicating the electronic effect of the substituent regardless of the substitution position. In the present invention, the σp value is used in this sense.

Examples of the electron-withdrawing group having a Hammett substituent constant σp value of 0.60 or more include a cyano group, a nitro group, and an alkylsulfonyl group (for example, a methanesulfonyl group and an arylsulfonyl group (for example, a benzenesulfonyl group)). .
Examples of the electron-withdrawing group having a Hammett σp value of 0.45 or more include an acyl group (for example, acetyl group), an alkoxycarbonyl group (for example, dodecyloxycarbonyl group), an aryloxycarbonyl group (for example, m-chlorophenoxycarbonyl) in addition to the above. ), An alkylsulfinyl group (for example, n-propylsulfinyl), an arylsulfinyl group (for example, phenylsulfinyl), a sulfamoyl group (for example, N-ethylsulfamoyl, N, N-dimethylsulfamoyl), a halogenated alkyl group ( For example, trifluoromethyl) can be mentioned.
As the electron-withdrawing group having a Hammett substituent constant σp value of 0.30 or more, in addition to the above, an acyloxy group (for example, acetoxy), a carbamoyl group (for example, N-ethylcarbamoyl, N, N-dibutylcarbamoyl), halogen Alkoxy group (for example, trifluoromethyloxy), halogenated aryloxy group (for example, pentafluorophenyloxy), sulfonyloxy group (for example, methylsulfonyloxy group), halogenated alkylthio group (for example, difluoromethylthio), 2 An aryl group (eg, 2,4-dinitrophenyl, pentachlorophenyl) substituted with one or more electron-withdrawing groups having a σp value of 0.15 or more, and a heterocycle (eg, 2-benzoxazolyl, 2- Benzothiazolyl, 1-phenyl-2-benzimidazolyl) be able to.
Specific examples of the electron-withdrawing group having a σp value of 0.20 or more include a halogen atom in addition to the above.

A particularly preferred combination of substituents as the azo dye represented by the general formula (4) is preferably a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, a sulfonyl group, or an acyl group as R ₅ and R ₆ . More preferred are a hydrogen atom, an aryl group, a heterocyclic group and a sulfonyl group, and most preferred are a hydrogen atom, an aryl group and a heterocyclic group. However, R ₅ and R ₆ are not both hydrogen atoms.
G is preferably a hydrogen atom, a halogen atom, an alkyl group, a hydroxyl group, an amino group, or an acylamino group, more preferably a hydrogen atom, a halogen atom, an amino group, or an acylamino group, most preferably a hydrogen atom, an amino group. Group, an acylamino group.
Among A, a pyrazole ring, an imidazole ring, an isothiazole ring, a thiadiazole ring, and a benzothiazole ring are preferable, a pyrazole ring and an isothiazole ring are further preferable, and a pyrazole ring is most preferable.
B ₁ and B ₂ are ═CR ₁ — and —CR ₂ ═, respectively, and R ₁ and R ₂ are preferably a hydrogen atom, an alkyl group, a halogen atom, a cyano group, a carbamoyl group, a carboxyl group, a hydroxyl group, respectively. , An alkoxy group and an alkoxycarbonyl group, and more preferably a hydrogen atom, an alkyl group, a carboxyl group, a cyano group and a carbamoyl group.

  In addition, about the preferable combination of a substituent of the compound represented by the said General formula (1), the compound whose at least 1 of a various substituent is the said preferable group is preferable, and many more various substituents are the said preferable. More preferred are compounds that are groups, and most preferred are compounds in which all substituents are the preferred groups.

  Specific examples of the azo dye represented by the general formula (1) are shown below, but the azo dye used in the present invention is not limited to the following examples, and also includes a carboxyl group, a phosphono group, and a sulfo group. May be in the form of a salt, and examples of counter ions that form salts include ammonium ions, alkali metal ions (eg, lithium ions, sodium ions, potassium ions) and organic cations (eg, tetramethylammonium ions, Tetramethylguanidinium ion, tetramethylphosphonium).

The following structures (b-8 to 20) are those in which the substituent A is substituted at the meta position with respect to the azo group linkage, and are particularly preferred examples in the present invention. In addition, it is the substituent A, the substituent B, and the substituent C in order from the left with respect to the paper surface.

  The dyes represented by the general formulas (1), (3), and (4) can be synthesized by a coupling reaction between a diazo component and a coupler. As the main synthesis method, it can be synthesized by the method described in Japanese Patent Application No. 2002-113460.

  The black ink of the present invention preferably contains 0.2 to 20% by mass of the azo dye, more preferably 0.5 to 15% by mass.

  If this dye (L) alone can achieve a high image quality “black (good) black = black that does not depend on the observation light source and any of the colors B, G, and R are difficult to emphasize” Although it is possible to use the dye alone as a black ink dye, it is generally used in combination with a dye that covers a region where the absorption of the dye is low. Usually, a preferable black is realized in combination with a dye or pigment having a main absorption in the yellow region. As a yellow dye, a direct dye or an acid dye represented by a commonly used azo dye or azomethine dye can be used. As the pigment, an aqueous dispersion of a general pigment having a pigment number can be used in combination. Among these, it is particularly preferable to use the dye represented by the general formula (1) as the short wave side dye (S) described above. At this time, A and C are preferably aromatic heterocycles.

  In any case, a dye having an oxidation potential (Eox) nobler than 1.0 V (vs SCE) is preferable, and a dye having an Eox of 1.2 V (vs SCE) or more is particularly preferable.

  It is also possible to produce a black ink by using another dye in combination.

  The black ink of the present invention contains the dye (L) and, if necessary, (S) (hereinafter also referred to as the black dye of the present invention) in an amount of 0.2 to 25% by mass, preferably 0.5 to Contains 15% by mass. The dye (S) can be used in an amount of 1 to 80% by mass based on the whole dye.

  The black ink of the present invention may be used in combination with other dyes in order to adjust the color tone together with the black dye of the present invention. In addition, the present invention can be an ink set comprising the black ink of the present invention and an ink using another dye in order to obtain a desired image such as a full color. The following can be mentioned as an example of the dye which can be used together. Further, as described above, the black ink of the present invention preferably contains a dye (S) having a λmax of 350 nm to 500 nm, and the following yellow dyes and yellow pigments are preferably used.

  Examples of yellow dyes include phenols, naphthols, anilines, pyrazolones, pyridones, aryl or heteryl azo dyes having open-chain active methylene compounds as coupling components; for example, open-chain active methylene compounds as coupling components. Azomethine dyes; methine dyes such as benzylidene dyes and monomethine oxonol dyes; quinone dyes such as naphthoquinone dyes and anthraquinone dyes, and other dye species such as quinophthalone dyes, nitro-nitroso dyes And dyes, acridine dyes, acridinone dyes and the like. These dyes may be those that exhibit yellow only after a part of the chromophore is dissociated, in which case the counter cation may be an alkali metal or an inorganic cation such as ammonium, pyridinium, It may be an organic cation such as a quaternary ammonium salt, and further may be a polymer cation having them in a partial structure.

  Examples of magenta dyes include aryl or heteryl azo dyes having phenols, naphthols, and anilines as coupling components; azomethine dyes having pyrazolones and pyrazolotriazoles as coupling components; for example, arylidene dyes, styryl dyes, and merocyanine Dyes, methine dyes such as oxonol dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, quinone dyes such as naphthoquinone, anthraquinone, anthrapyridone, etc. And ring dyes. These dyes may exhibit magenta only after part of the chromophore is dissociated, and the counter cation in that case may be an alkali metal or an inorganic cation such as ammonium, pyridinium, It may be an organic cation such as a quaternary ammonium salt, and further may be a polymer cation having them in a partial structure.

Examples of cyan dyes include azomethine dyes such as indoaniline dyes and indophenol dyes; polymethine dyes such as cyanine dyes, oxonol dyes and merocyanine dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes and xanthene dyes; phthalocyanine Dyes; anthraquinone dyes; For example, aryl or heteryl azo dyes having phenols, naphthols and anilines as coupling components, and indigo / thioindigo dyes can be mentioned. These dyes may exhibit cyan only after a part of the chromophore is dissociated, and the counter cation in that case may be an alkali metal or an inorganic cation such as ammonium, pyridinium, It may be an organic cation such as a quaternary ammonium salt, and further may be a polymer cation having them in a partial structure.
Moreover, black dyes, such as polyazo dyes other than the black dye of this invention, can also be used.

In addition, water-soluble dyes such as direct dyes, acid dyes, food dyes, basic dyes, and reactive dyes can be used in combination. Among them, preferred is
C. I. Direct Red 2, 4, 9, 23, 26, 31, 39, 62, 63, 72, 75, 76, 79, 80, 81, 83, 84, 89, 92, 95, 111, 173, 184, 207, 211, 212, 214, 218, 21, 223, 224, 225, 226, 227, 232, 233, 240, 241, 242, 243, 247
C. I. Direct violet 7, 9, 47, 48, 51, 66, 90, 93, 94, 95, 98, 100, 101
C. I. Direct yellow 8, 9, 11, 12, 27, 28, 29, 33, 35, 39, 41, 44, 50, 53, 58, 59, 68, 86, 87, 93, 95, 96, 98, 100, 106, 108, 109, 110, 130, 132, 142, 144, 161, 163
C. I. Direct Blue 1, 10, 15, 22, 25, 55, 67, 68, 71, 76, 77, 78, 80
, 84, 86, 87, 90, 98, 106, 108, 109, 151, 156, 158, 159, 160, 168, 189,
192, 193, 194, 199, 200, 201, 202, 203, 207, 211, 213, 214, 218, 225, 229, 236, 237, 244, 248, 249, 251, 252, 264, 270, 280, 288, 289, 291
C. I. Direct Black 9, 17, 19, 22, 32, 51, 56, 62, 69, 77, 80, 91, 94, 97, 108, 112, 113, 114, 117, 118, 121, 122, 125, 132, 146, 154, 166, 168, 173, 199
C. I. Acid Red 35, 42, 52, 57, 62, 80, 82, 111, 114, 118, 119, 127,
128, 131, 143, 151, 154, 158, 249, 254, 257, 261, 263, 266, 289, 299, 301, 305, 336, 337, 361, 396, 397
C. I. Acid Violet 5, 34, 43, 47, 48, 90, 103, 126
C. I. Acid Yellow 17, 19, 23, 25, 39, 40, 42, 44, 49, 50, 61, 64, 76, 79, 110, 127, 135, 143, 151, 159, 169, 174, 190, 195, 196, 197, 199, 218, 219, 222, 227
C. I. Acid Blue 9, 25, 40, 41, 62, 72, 76, 78, 80, 82, 92, 106, 112,
113, 120, 127: 1, 129, 138, 143, 175, 181, 205, 207, 220, 221, 230, 232, 247, 258, 260, 264, 271, 277, 278, 279, 280, 288, 290, 326
C. I. Acid Black 7, 24, 29, 48, 52: 1, 172
C. I. Reactive Red 3, 13, 17, 19, 21, 22, 23, 24, 29, 35, 37, 40, 41, 43, 45, 49, 55
C. I. Reactive violet 1, 3, 4, 5, 6, 7, 8, 9, 16, 17, 22, 23, 24, 26, 27, 33, 34
C. I. Reactive Yellow 2, 3, 13, 14, 15, 17, 18, 23, 24, 25, 26, 27, 29, 35, 37, 41, 42
C. I. Reactive Blue 2, 3, 5, 8, 10, 13, 14, 15, 17, 18, 19, 21, 25, 26, 27, 28, 29, 38
C. I. Reactive Black 4, 5, 8, 14, 21, 23, 26, 31, 32, 34
C. I. Basic Red 12, 13, 14, 15, 18, 22, 23, 24, 25, 27, 29, 35, 36, 38, 39, 45, 46
C. I. Basic violet 1, 2, 3, 7, 10, 15, 16, 20, 21, 25, 27, 28, 35, 37, 39, 40, 48
C. I. Basic yellow 1, 2, 4, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 39, 40
C. I. Basic Blue 1, 3, 5, 7, 9, 22, 26, 41, 45, 46, 47, 54, 57, 60, 62, 65, 66, 69, 71
C. I. Basic black 8, etc. are mentioned.

Furthermore, a pigment can be used in combination.
As the pigment that can be used in the black ink of the present invention, commercially available pigments and known pigments described in various documents can be used. For the literature, Color Index (Edited by The Society of Dyers and Colorists), “Revised New Handbook of Pigments” edited by Japan Pigment Technology Association (1989), “Latest Pigment Applied Technology” CMC Publishing (1986), “Printing Ink Technology” CMC Publishing (1984), W. Herbst, K.M. Hunger co-authored Industrial Organic Pigments (VCH Verlagsgesellschaft, published in 1993). Specifically, as organic pigments, azo pigments (azo lake pigments, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, indigo pigments, quinacridone Pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments), dyed lake pigments (acid or basic dye lake pigments), azine pigments, etc. C.I. of yellow pigment I. Pigment Yellow 34, 37, 42, 53, and other red pigments such as C.I. I. Pigment Red 101, 108, etc., blue pigments such as C.I. I. Pigment Blue 27, 29, 17: 1, etc. I. Pigment Black 7, magnetite, and other white pigments such as C.I. I. Pigment White 4, 6, 18, 21 and the like.

  As a pigment having a preferable color tone for image formation, a phthalocyanine pigment, an anthraquinone-based indanthrone pigment (for example, CI Pigment Blue 60), and a dyed lake pigment-based triarylcarbonium pigment are preferable for a blue or cyan pigment. In particular, phthalocyanine pigments (preferred examples include copper phthalocyanine such as CI Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, monochloro or low chlorinated copper). Among the phthalocyanines and alnium phthalocyanines, the pigments described in European Patent No. 860475, the metal-free phthalocyanine which is CI Pigment Blue 16, the phthalocyanines whose central metals are Zn, Ni and Ti, and the like are preferable among them. nt Blue 15: 3, 15: 4, aluminum phthalocyanine).

  For red to violet pigments, azo pigments (preferred examples include CI Pigment Red 3, 5, 11, 22, 38, 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 52: 1, 53: 1, 57: 1, 63: 2, 144, 146, and 184). I. Pigment Red 57: 1, 146, 184), quinacridone pigments (preferred examples include CI Pigment Red 122, 192, 202, 207, 209, CI Pigment Violet 19, 42, particularly preferred are CI Pigment Red 122), dyed lake pigment-based triarylcarbonium pigments (preferred examples include xanthene-based CI Pigment Red 81: 1, C.I. Pigment Violet). 1, 2, 3, 27, 39), dioxazine pigments (for example, CI Pigment Violet 23, 37), diketopyrrolopyrrole pigments (for example, CI Pigment Red 254), perylene Pigment ( For example, CI Pigment Violet 29), anthraquinone pigments (for example, CI Pigment Violet 5: 1, 31, 33), and thioindigo (for example, CI Pigment Red 38, 88) are preferably used. It is done.

  Examples of yellow pigments include azo pigments (preferred examples include monoazo pigment-based CI Pigment Yellow 1, 3, 74, 98, disazo pigment-based CI Pigment Yellow 12, 13, 14, 16, 17, 83, synthetic azo-based CI Pigment Yellow 93, 94, 95, 128, 155, benzimidazolone-based CI Pigment Yellow 120, 151, 154, 156, 180, etc., among which benzidine is preferred. That are not used as raw materials), isoindoline / isoindolinone pigments (preferred examples include CI Pigment Yellow 109, 110, 137, and 139), quinophthalone pigments (preferred examples include C C. I. Pigment Yellow 138), flavanthrone pigments (e.g., C. I. Pigment Yellow 24, etc.) are preferably used.

Preferred examples of the black pigment include inorganic pigments (preferably carbon black and magnetite as examples) and aniline black.
In addition, an orange pigment (C.I. Pigment Orange 13, 16, etc.) or a green pigment (C.I. Pigment Green 7, etc.) may be used.

The pigment that can be used in the black ink of the present invention may be the above-mentioned bare pigment or a surface-treated pigment. Surface treatment methods include resin or wax surface coating, surfactant attachment, reactive substances (eg radicals derived from silane coupling agents, epoxy compounds, polyisocyanates, diazonium salts, etc.) pigments A method of bonding to the surface is conceivable, and is described in the following documents and patents.
(1) The nature and application of metal soap (Shoshobo)
(2) Printing ink printing (CMC Publishing 1984)
(3) Latest pigment application technology (CMC Publishing 1986)
(4) U.S. Pat. Nos. 5,554,739, 5,571,311 (5) JP-A-9-151342, 10-140065, 10-292143, 11-166145 Self-dispersing pigments prepared by allowing a diazonium salt described in US Patent 4) to act on carbon black and encapsulated pigments prepared by the method described in Japanese Patent (5) above are used in inks. In particular, the dispersion stability can be obtained without using an extra dispersant.

In the black ink of the present invention, the pigment may be further dispersed using a dispersant. Various known dispersants can be used in accordance with the pigment to be used, for example, a surfactant-type low-molecular dispersant or a polymer-type dispersant. Examples of the dispersant include those described in JP-A-3-69949, European Patent 549486 and the like. In addition, when a dispersant is used, a pigment derivative called a synergist may be added to promote adsorption of the dispersant to the pigment.
The particle diameter of the pigment that can be used in the black ink of the present invention is preferably in the range of 0.01 to 10 μm after dispersion, and more preferably 0.05 to 1 μm.
As a method for dispersing the pigment, a known dispersion technique used in ink production or toner production can be used. Examples of the disperser include vertical or horizontal agitator mills, attritors, colloid mills, ball mills, three roll mills, pearl mills, super mills, impellers, dispersers, KD mills, dynatrons, and pressure kneaders. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

  The black ink of the present invention can be prepared by including a black dye in an aqueous medium. The means for containing the black dye is preferably dissolved and / or dispersed. The “aqueous medium” in the present invention means water or water added with a component such as a water-miscible organic solvent, a wetting agent, a stabilizer, a preservative, etc. as necessary.

  The water-miscible organic solvent that can be used in the present invention is a material having functions such as an anti-drying agent, a penetration accelerator, and a wetting agent for ink jet recording inks in the field, and is mainly a high-boiling water-miscible material. An organic solvent is used. Such compounds include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyhydric alcohols (eg, , Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), glycol derivatives (eg, ethylene glycol monomethyl) Ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether Diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, triethylene glycol Monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monophenyl ether), amine (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine) , Reethylenetetramine, polyethyleneimine, tetramethylpropylenediamine) and other polar solvents (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2- Pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone). In addition, the said water miscible organic solvent may use 2 or more types together.

Among these, alcohol solvents are particularly preferable.
These water-miscible organic solvents are preferably contained in the ink in a total amount of 5 to 60% by mass, particularly preferably 10 to 45% by mass.

When preparing the black ink of the present invention, if the dye is water-soluble, it is preferably dissolved in water first. Thereafter, various solvents and additives are added, dissolved and mixed to obtain a uniform ink solution.
As the dissolution method at this time, various methods such as dissolution by stirring, dissolution by ultrasonic irradiation, and dissolution by shaking can be used. Of these, the stirring method is particularly preferably used. In the case of stirring, various methods such as fluidized stirring known in the art and stirring using shearing force using an inverted agitator or dissolver can be used. On the other hand, a stirring method using a shearing force with the bottom surface of the container, such as a magnetic stirrer, can also be preferably used.

By adding a surfactant to the black ink of the present invention and adjusting the liquid physical properties of the ink, the ink ejection stability is improved, and the water resistance of the image is improved and the bleeding of the printed ink is excellent. Can have an effect.
Examples of the surfactant include anionic surfactants such as sodium dodecyl sulfate, sodium dodecyloxysulfonate, and sodium alkylbenzene sulfonate, and cationic surfactants such as cetyl pyridinium chloride, trimethyl cetyl ammonium chloride, and tetrabutyl ammonium chloride. And nonionic surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene naphthyl ether, polyoxyethylene octylphenyl ether, and the like. Among these, nonionic surfactants are particularly preferably used.

  The content of the surfactant is 0.001 to 20% by mass, preferably 0.005 to 10% by mass, and more preferably 0.01 to 5% by mass with respect to the ink.

When the black dye of the present invention is an oil-soluble dye, it can be prepared by dissolving the oil-soluble dye in a high boiling point organic solvent and emulsifying and dispersing it in an aqueous medium.
The boiling point of the high-boiling organic solvent used in the present invention is 150 ° C. or higher, preferably 170 ° C. or higher.
For example, phthalic acid esters (for example, dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl phthalate, decyl phthalate, bis (2,4-di-tert-amylphenyl) isophthalate, bis (1, 1-diethylpropyl) phthalate), esters of phosphoric acid or phosphones (eg diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, 2-ethylhexyl diphenyl phosphate, dioctyl butyl phosphate, tricyclohexyl phosphate, tri-2-ethylhexyl phosphate , Tridodecyl phosphate, di-2-ethylhexylphenyl phosphate), benzoic acid esters (eg 2-ethylhexyl benzoate, 2,4-dicarbonate) Lobenzoate, dodecylbenzoate, 2-ethylhexyl-p-hydroxybenzoate), amides (eg, N, N-diethyldodecanamide, N, N-diethyllaurylamide), alcohols or phenols (isostearyl alcohol, 2, 4-di-tert-amylphenol), aliphatic esters (eg, dibutoxyethyl succinate, di-2-ethylhexyl succinate, 2-hexyldecyl tetradecanoate, tributyl citrate, diethyl azelate, isostearyl lactate , Trioctyl citrate), aniline derivatives (N, N-dibutyl-2-butoxy-5-tert-octylaniline, etc.), chlorinated paraffins (paraffins having a chlorine content of 10% to 80%), trimesic acid esters Kind (for example, Tributyl trimesate), dodecylbenzene, diisopropylnaphthalene, phenols (eg, 2,4-di-tert-amylphenol, 4-dodecyloxyphenol, 4-dodecyloxycarbonylphenol, 4- (4-dodecyloxyphenylsulfonyl)) Phenol), carboxylic acids (eg, 2- (2,4-di-tert-amylphenoxybutyric acid, 2-ethoxyoctanedecanoic acid), alkylphosphoric acids (eg, di-2 (ethylhexyl) phosphoric acid, diphenylphosphoric acid) The high-boiling organic solvent can be used in an amount of 0.01 to 3 times, preferably 0.01 to 1.0 times the mass ratio of the oil-soluble dye.
These high-boiling organic solvents may be used alone or in a mixture of several types (eg tricresyl phosphate and dibutyl phthalate, trioctyl phosphate and di (2-ethylhexyl) sebacate, dibutyl phthalate and poly (Nt-butyl). Acrylamide)].

Examples of other high boiling point organic solvents used in the present invention and / or methods for synthesizing these high boiling point organic solvents are disclosed in, for example, US Pat. Nos. 2,322,027, 2,533,514, and 2 772,163, 2,835,579, 3,594,171, 3,676,137, 3,689,271, 3,700,454 3,748,141, 3,764,336, 3,765,897, 3,912,515, 3,936,303, 4, No. 004,928, No. 4,080,209, No. 4,127,413, No. 4,193,802, No. 4,207,393, No. 4,220,711, No. 4,239,851, No. 4,278,757, No. 4 353,979, 4,363,873, 4,430,421, 4,430,422, 4,464,464, 4,483,918, 4,540,657, 4,684,606, 4,728,599, 4,745,049, 4,935,321, 5,013 , 639, European Patent Nos. 276,319A, 286,253A, 289,820A, 309,158A, 309,159A, 309,160A, 509 No. 311A, No. 510,576A, East German Patent No. 147,009, No. 157,147, No. 159,573, No. 225,240A, British Patent No. 2,091,124A, JP-A-48-47335, 50 No. 26530, No. 51-25133, No. 51-26036, No. 51-27921, No. 51-27922, No. 51-149028, No. 52-46816, No. 53-1520, No. 53-1521 53-15127, 53-146622, 54-91325, 54-106228, 54-118246, 55-59464, 56-64333, 56-81836, 59-204041, 61-84641, 62-118345, 62-247364, 63-167357, 63-214744, 63-301941, 63-94552, 64-945 9454, 64-68745, JP-A-1-101543, 1-102454, 2-792, and 2 No.-4239, No. 2-43541, No. 4-29237, No. 4-30165, No. 4-232946, No. 4-346338 and the like.
The high boiling point organic solvent is used in an amount of 0.01 to 3.0 times, preferably 0.01 to 1.0 times the mass ratio of the oil-soluble dye.

  In the present invention, the oil-soluble dye and the high boiling point organic solvent are emulsified and dispersed in an aqueous medium. In the emulsification dispersion, a low boiling organic solvent can be used depending on the case from the viewpoint of emulsification. The low boiling point organic solvent is an organic solvent having a boiling point of about 30 ° C. or higher and 150 ° C. or lower at normal pressure. For example, esters (eg ethyl acetate, butyl acetate, ethyl propionate, β-ethoxyethyl acetate, methyl cellosolve acetate), alcohols (eg isopropyl alcohol, n-butyl alcohol, secondary butyl alcohol), ketones (eg methyl isobutyl) Ketones, methyl ethyl ketone, cyclohexanone), amides (for example, dimethylformamide, N-methylpyrrolidone), ethers (for example, tetrahydrofuran, dioxane) and the like are preferably used, but are not limited thereto.

The emulsification dispersion is used to disperse an oil phase in which a dye is dissolved in a mixed solvent of a high-boiling organic solvent and, optionally, a low-boiling organic solvent, in an aqueous phase mainly composed of water to form fine oil droplets in the oil phase. Done. At this time, components such as a surfactant, a wetting agent, a dye stabilizer, an emulsion stabilizer, an antiseptic, and an antifungal agent can be added to either or both of the aqueous phase and the oil phase as necessary. .
As an emulsification method, a method of adding an oil phase to an aqueous phase is common, but a so-called phase inversion emulsification method in which an aqueous phase is dropped into an oil phase can also be preferably used. The emulsification method can also be applied when the black dye of the present invention is water-soluble and the component is oil-soluble.

  When emulsifying and dispersing, various surfactants can be used. Anionic interfaces such as fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl sulfates, etc. Activator, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethyleneoxypropylene block copolymer Nonionic surfactants such as Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred. Further, pages (37) to (38) of JP-A-59-157,636, Research Disclosure No. The surfactants described in 308119 (1989) can also be used.

  For the purpose of stabilization immediately after emulsification, a water-soluble polymer can be added in combination with the surfactant. As the water-soluble polymer, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polyacrylic acid, polyacrylamide or a copolymer thereof is preferably used. It is also preferable to use natural water-soluble polymers such as polysaccharides, casein, and gelatin. Further, for stabilization of the dye dispersion, acrylic acid esters, methacrylic acid esters, vinyl esters, acrylamides, methacrylamides, olefins, styrenes, vinyl ethers that are not substantially soluble in an aqueous medium, Polyvinyl, polyurethane, polyester, polyamide, polyurea, polycarbonate and the like obtained by polymerization of acrylonitrile can also be used in combination. These polymers preferably contain -SO3- and -COO-. When these polymers that do not substantially dissolve in an aqueous medium are used in combination, it is preferably used in an amount of 20% by mass or less, more preferably 10% by mass or less of the high boiling point organic solvent.

When an oil-soluble dye or a high-boiling organic solvent is dispersed by emulsification to obtain a water-based ink, control of the particle size is particularly important. In order to increase color purity and density when an image is formed by inkjet, it is essential to reduce the average particle size. The volume average particle size is preferably 1 μm or less, more preferably 5 to 100 nm.
In addition to static light scattering, dynamic light scattering, and centrifugal sedimentation, the methods for measuring the volume average particle size and particle size distribution of the dispersed particles are described in pages 417 to 418 of Experimental Chemistry Course 4th edition. It can be easily measured by a known method such as using a method. For example, after dilution with distilled water so that the particle concentration in the ink is 0.1 to 1% by mass, it is easy with a commercially available volume average particle size measuring device (for example, Microtrac UPA (manufactured by Nikkiso Co., Ltd.)). Can be measured. Furthermore, the dynamic light scattering method using the laser Doppler effect is particularly preferable because it can measure the particle size up to a small size.
The volume average particle diameter is an average particle diameter weighted by the particle volume, and is the sum of the diameter of each particle multiplied by the volume of the particle divided by the total volume of the particles. The volume average particle diameter is described on page 119 of “Chemistry of Polymer Latex (by Soichi Muroi, Polymer Press Society)”.

It was also found that the presence of coarse particles also plays a very important role in printing performance. That is, it has been found that the coarse particles clog the nozzles of the head, or even if they are not clogged, the ink is not ejected or the ink is not ejected, resulting in a serious influence on the printing performance. In order to prevent this, it is important to limit the number of particles of 5 μm or more to 10 or less and 1 μm or more to 1000 or less in 1 μl of ink.
As a method for removing these coarse particles, a known centrifugal separation method, microfiltration method, or the like can be used. These separation means may be performed immediately after the emulsification dispersion, or may be performed immediately after filling the ink dispersion after adding various components such as a wetting agent and a surfactant to the emulsification dispersion.
A mechanical emulsifier can be used as an effective means for reducing the average particle size and eliminating coarse particles.

As the emulsifying device, known devices such as a simple stirrer, impeller stirring method, in-line stirring method, mill method such as colloid mill, and ultrasonic method can be used, but the use of a high-pressure homogenizer is particularly preferable.
The high-pressure homogenizer is described in detail in US Pat. No. 4,533,254, JP-A-6-47264, and the like, but as a commercially available device, a Gorin homogenizer (APV GAULIN INC.), A microfluidizer ( MICROFLUIDEX INC.), Optimizer (Sugino Machine Co., Ltd.) and the like.
In addition, a high-pressure homogenizer equipped with a mechanism for atomizing in an ultrahigh-pressure jet stream as described in US Pat. No. 5,720,551 in recent years is particularly effective for the emulsification dispersion of the present invention. An example of an emulsifying apparatus using this ultra-high pressure jet flow is DeBEE2000 (BEE INTERNIONAL LTD.).

The pressure when emulsifying with the high-pressure emulsifying dispersion device is 50 MPa or more, preferably 60 MPa or more, more preferably 180 MPa or more.
For example, it is a particularly preferable method that two or more types of emulsifiers are used together by a method such as emulsification with a stirring emulsifier and then passing through a high-pressure homogenizer. In addition, a method of once emulsifying and dispersing with these emulsifiers, adding components such as a wetting agent and a surfactant, and then passing the high-pressure homogenizer again while filling the cartridge with ink is also a preferable method.
When a low boiling point organic solvent is contained in addition to the high boiling point organic solvent, it is preferable to remove the low boiling point solvent from the viewpoint of the stability of the emulsion and safety and health. Various known methods can be used as the method for removing the low boiling point solvent depending on the type of the solvent. That is, an evaporation method, a vacuum evaporation method, an ultrafiltration method, and the like. This step of removing the low-boiling organic solvent is preferably performed as soon as possible immediately after emulsification.

  Ink jet ink preparation methods are described in detail in JP-A Nos. 5-148436, 5-295212, 7-97541, 7-82515, and 7-118584. Thus, it can also be used for preparing the black ink of the present invention.

  The ink for inkjet recording obtained in the present invention can contain a functional component for imparting various functions to the ink. For example, as the functional component, the above-mentioned various solvents, a drying preventive agent for preventing clogging due to dry operation at the ink ejection port, a penetration enhancer for allowing the ink to permeate the paper better, an ultraviolet absorber, Antioxidants, viscosity modifiers, surface tension modifiers, dispersants, dispersion stabilizers, antifungal agents, rust preventive agents, pH adjusters, antifoaming agents, chelating agents, and the like, and the black ink of the present invention These can be appropriately selected and used in appropriate amounts. These functional components include a single compound that can exhibit one or more functions. Therefore, in the following blending ratio of the functional component, the handling of the functional component in the case where the function is duplicated shall include the compound in each functional component independently.

  The drying inhibitor used in the present invention is preferably a water-soluble organic solvent having a vapor pressure lower than that of water. Specific examples include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivatives, glycerin. Polyhydric alcohols typified by trimethylolpropane, etc., lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monoethyl (or butyl) ether 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, heterocyclic rings such as N-ethylmorpholine, sulfolane, dimethyl sulfoxide, 3 Sulfur-containing compounds such as sulfolane, diacetone alcohol, polyfunctional compounds such as diethanolamine, and urea derivatives. Of these, polyhydric alcohols such as glycerin and diethylene glycol are more preferred. Moreover, said drying inhibitor may be used independently and may be used together 2 or more types. These drying inhibitors are preferably contained in the ink in an amount of 10 to 50% by mass.

  Examples of penetration enhancers used in the present invention include alcohols such as ethanol, isopropanol, butanol, di (tri) ethylene glycol monobutyl ether, 1,2-hexanediol, sodium lauryl sulfate, sodium oleate, and nonionic surfactants. Etc. can be used. If these are contained in the ink in an amount of 10 to 30% by mass, the effect is sufficient, and it is preferable to use them in a range of addition amounts that do not cause printing bleeding and paper loss (print through).

  Examples of the ultraviolet absorber used for improving the storability of the image in the present invention include JP-A Nos. 58-185677, 61-190537, JP-A-2-782, and JP-A-5-97075. Benzotriazole compounds described in JP-A-9-34057, etc., benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194443, US Pat. No. 3,214,463, etc. Cinnamic acid compounds described in JP-A-48-30492, JP-A-56-21141, JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, JP-A-8-239368. And triazine compounds described in JP-A-10-182621, JP-A-8-501291, etc. Jar No. Compounds described in No. 24239, compounds that emit fluorescence by absorbing ultraviolet rays typified by stilbene-based compounds and benzoxazole-based compounds, so-called fluorescent brighteners, can also be used.

  In the present invention, various organic and metal complex anti-fading agents can be used as the antioxidant used to improve image storage stability. Organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, heterocycles, etc. Complex, zinc complex and the like. More specifically, Research Disclosure No. No. 17643, No. VII, I to J, ibid. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of the representative compounds described in pages 127 to 137 of JP-A-62-215272 can be used.

Antifungal agents used in the present invention include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and its salts. Can be mentioned. These are preferably used in the ink in an amount of 0.02 to 5.00% by mass.
Details of these are described in “Encyclopedia of Antibacterial and Antifungal Agents” (edited by the Japanese Association of Antimicrobial and Antifungal Society).
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and benzotriazole. These are preferably used in the ink in an amount of 0.02 to 5.00% by mass.

The pH adjuster used in the present invention can be suitably used in terms of adjusting pH, imparting dispersion stability, etc., and the pH of the ink at 25 ° C. is preferably adjusted to 8-11. When the pH is less than 8, the solubility of the dye is lowered and the nozzle is easily clogged, and when it exceeds 11, the water resistance tends to deteriorate. Examples of the pH adjuster include organic bases and inorganic alkalis as basic substances, and organic acids and inorganic acids as acidic substances.
Basic compounds include inorganic compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium acetate, potassium acetate, sodium phosphate, sodium hydrogen phosphate, aqueous ammonia, Use organic bases such as methylamine, ethylamine, diethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, ethylenediamine, piperidine, diazabicyclooctane, diazabicycloundecene, pyridine, quinoline, picoline, lutidine, collidine Is also possible.
Examples of acidic compounds include inorganic compounds such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, sodium hydrogen sulfate, potassium hydrogen sulfate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, acetic acid, tartaric acid, benzoic acid, trifluoroacetic acid. Organic compounds such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, saccharic acid, phthalic acid, picolinic acid and quinolinic acid can also be used.

The conductivity of the black ink of the present invention is in the range of 0.01 to 10 S / m. Among these, a preferable range is a conductivity of 0.05 to 5 S / m.
The conductivity can be measured by an electrode method using commercially available saturated potassium chloride.
The conductivity can be controlled mainly by the ion concentration in the aqueous solution. When the salt concentration is high, desalting can be performed using an ultrafiltration membrane or the like. Moreover, when adjusting conductivity by adding salt etc., it can adjust by adding various organic substance salt and inorganic substance salt.
Inorganic salts include potassium halide, sodium halide, sodium sulfate, potassium sulfate, sodium hydrogen sulfate, potassium hydrogen sulfate, sodium nitrate, potassium nitrate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium phosphate, sodium monohydrogen phosphate, Inorganic compounds such as boric acid, potassium dihydrogen phosphate, sodium dihydrogen phosphate, sodium acetate, potassium acetate, potassium tartrate, sodium tartrate, sodium benzoate, potassium benzoate, sodium p-toluenesulfonate, potassium saccharinate Organic compounds such as potassium phthalate and sodium picolinate can also be used.
The conductivity can also be adjusted by selecting the components of the aqueous medium described later.

The black ink viscosity of the present invention is preferably 1 to 20 mPa · s at 25 ° C. More preferably, it is 2-15 mPa * s, Most preferably, it is 2-10 mPa * s. If it exceeds 20 mPa · s, the fixing speed of the recorded image becomes slow, and the discharge performance also deteriorates. If it is less than 1 mPa · s, the recorded image is blurred and the quality is lowered.
The viscosity can be arbitrarily adjusted by adding the ink solvent. Examples of the ink solvent include glycerin, diethylene glycol, triethanolamine, 2-pyrrolidone, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether.
A viscosity modifier may be used. Examples of the viscosity modifier include water-soluble polymers such as celluloses and polyvinyl alcohol, and nonionic surfactants. More specifically, “Viscosity Preparation Technology” (Technical Information Association, 1999), Chapter 9, and “Chemicals for Inkjet Printers (98 Supplement) —Material Development Trends and Prospects Survey” (CMC, 1997) 162- Page 174.

  The method for measuring the viscosity of the liquid is described in detail in JIS Z8803, but can be easily measured with a commercially available viscometer. For example, the rotary type includes Tokyo Keiki B-type viscometer and E-type viscometer. In this invention, it measured at 25 degreeC by the vibration type VM-100AL type of Yamaichi Electric. The unit of viscosity is Pascal second (Pa · s), but millipascal second (mPa · s) is usually used.

The surface tension of the ink used in the present invention is preferably 20 to 50 mN / m, more preferably 20 to 40 mN / m at 25 ° C. for both dynamic and static surface tension. If the surface tension exceeds 50 mN / m, the ejection quality, bleeding at the time of color mixing, print quality such as whiskers, etc. will be significantly reduced. If the surface tension of the ink is 20 mN / m or less, there may be a printing failure due to ink adhesion to the hard surface during ejection.
For the purpose of adjusting the surface tension, various cations, anions, nonionic surfactants and betaine surfactants can be added. Moreover, 2 or more types of surfactant can be used together.

As a static surface tension measuring method, a capillary rising method, a dropping method, a hanging ring method and the like are known. In the present invention, a vertical plate method is used as a static surface tension measuring method.
When a thin plate of glass or platinum is partially immersed in the liquid and suspended vertically, the surface tension of the liquid acts downward along the length of contact between the liquid and the plate. The surface tension can be measured by balancing this force with an upward force.

  Examples of the dynamic surface tension measurement method include “New Experimental Chemistry Course, Vol. 18, Interface and Colloid” [Maruzen Co., Ltd., p. 69-90 (1977)], the vibration jet method, the meniscus dropping method, the maximum bubble pressure method and the like are known, and further, the liquid film breakage as described in JP-A-3-2064 is known. In the present invention, a bubble pressure differential pressure method is used as a dynamic surface tension measurement method. The measurement principle and method will be described below.

  When bubbles are generated in the solution that has become homogeneous by stirring, a new gas-liquid interface is generated, and the surfactant molecules in the solution gather on the surface of the water at a constant rate. When the bubble rate (bubble generation rate) is changed, if the generation rate slows down, more surfactant molecules gather on the surface of the bubble, so the maximum bubble pressure just before the bubble pops is reduced, The maximum bubble pressure (surface tension) relative to the bubble rate can be detected. As a preferable dynamic surface tension measurement, a method is used in which bubbles are generated in a solution using two large and small probes, the differential pressure in the maximum bubble pressure state of the two probes is measured, and the dynamic surface tension is calculated. Can be mentioned.

The non-volatile component in the black ink of the present invention is 10 to 70% by mass of the total amount of the ink. It is preferable in terms of reduction in stickiness, and is more preferably 20 to 60% by mass in terms of ink ejection stability and reduction in image bleeding after printing.
Here, the non-volatile component means a liquid, a solid component or a high molecular weight component having a boiling point of 150 ° C. or higher under 1 atm. Non-volatile components of ink-jet ink are dyes, high boiling point solvents, polymer latex added as necessary, surfactants, dye stabilizers, antifungal agents, buffering agents, etc., and many of these non-volatile components are Other than dye stabilizers, the dispersion stability of the ink is reduced, and since it remains on the inkjet image-receiving paper after printing, the stability due to the association of dyes on the image-receiving paper is hindered. It has the property of exacerbating image bleeding under conditions.

  In the present invention, a high molecular weight compound can also be contained. Here, the high molecular weight compound means all high molecular compounds having a number average molecular weight of 5000 or more contained in the ink. These polymer compounds are soluble in water-soluble polymer compounds that are substantially soluble in aqueous media, water-dispersible polymer compounds such as polymer latex and polymer emulsion, and polyhydric alcohols that are used as auxiliary solvents. Alcohol-soluble polymer compounds and the like can be mentioned, but any compound that substantially dissolves or disperses uniformly in the ink liquid is included in the high molecular weight compound in the present invention.

Specific examples of the water-soluble polymer compound include polyvinyl alcohol, silanol-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyethylene oxide, water-soluble polymers such as polyoxyalkylene oxide such as polypropylene oxide, and polyalkylene oxide derivatives. polysaccharides, starch, cationized starch, casein, natural water-soluble polymers such as gelatin, polyacrylic acid, polyacrylamide or aqueous acrylic resins such as a copolymer thereof, aqueous alkyd resins, -SO in the molecule ₃ ^-, Examples thereof include water-soluble polymer compounds having a —COO 2 ^— group and substantially soluble in an aqueous medium.
Examples of the polymer latex include styrene-butadiene latex, styrene-acrylic latex, and polyurethane latex. Furthermore, an acrylic emulsion etc. are mentioned as a polymer emulsion.
These water-soluble polymer compounds can be used alone or in combination of two or more.

As described above, the water-soluble polymer compound is used as a viscosity modifier to adjust the viscosity of the ink in a viscosity region having good ejection characteristics. However, if the amount of the water-soluble polymer compound added is large, the viscosity of the ink increases. As a result, the ejection stability of the ink liquid is lowered, and the nozzle is easily clogged by the precipitate when the ink is aged.
The addition amount of the polymer compound of the viscosity modifier depends on the molecular weight of the compound to be added (the higher the molecular weight, the smaller the addition amount may be), but the addition amount is 0 to 5% by mass with respect to the total amount of the ink, preferably Is 0 to 3% by mass, more preferably 0 to 1% by mass.

  Further, in the present invention, the above-mentioned cation, anion, nonionic and betaine surfactants are necessary as a dispersant and dispersion stabilizer, and fluorine-based, silicone-based compounds and chelating agents represented by EDTA are required as an antifoaming agent. Can be used according to.

The reflective media used in the present invention will be described. Examples of reflective media include recording paper and recording film. The support for recording paper and recording film is made of chemical pulp such as LBKP and NBKP, mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMP, and CGP, and waste paper pulp such as DIP. Additives such as known pigments, binders, sizing agents, fixing agents, cationic agents, paper strength enhancers, etc. can be mixed and manufactured using various devices such as long net paper machines and circular net paper machines. is there. As the support, in addition to these supports, either synthetic paper or plastic film sheet may be used. The thickness of the support is preferably 10 to 250 μm and the basis weight is preferably 10 to 250 g / m ² .
An image receiving layer and a back coat layer may be provided on the support as they are, and the image receiving material for the black ink of the present invention may be used. It may be provided as an image receiving material. Further, the support may be flattened by a calendar device such as a machine calendar, a TG calendar, or a soft calendar.
In the present invention, as the support, paper and plastic film laminated on both sides with polyolefin (eg, polyethylene, polystyrene, polybutene and copolymers thereof) or polyethylene terephthalate are more preferably used. It is preferable to add a white pigment (eg, titanium oxide, zinc oxide) or a coloring dye (eg, cobalt blue, ultramarine blue, neodymium oxide) to the polyolefin.

  The image receiving layer provided on the support contains a porous material and an aqueous binder. The image receiving layer preferably contains a pigment, and the pigment is preferably a white pigment. White pigments include calcium carbonate, kaolin, talc, clay, diatomaceous earth, synthetic amorphous silica, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, alumina, lithopone, zeolite, barium sulfate, calcium sulfate, titanium dioxide, Examples thereof include inorganic white pigments such as zinc sulfide and zinc carbonate, organic pigments such as styrene pigments, acrylic pigments, urea resins and melamine resins. A porous white inorganic pigment is particularly preferable, and synthetic amorphous silica having a large pore area is particularly preferable. As the synthetic amorphous silica, either anhydrous silicic acid obtained by a dry production method (gas phase method) or hydrous silicic acid obtained by a wet production method can be used.

  Specific examples of the recording paper containing the pigment in the image receiving layer include JP-A Nos. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, and JP-A-2001-138621. 2000-43401, 2000-2111235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8-2091, 8-9. 2093, 8-174992, 11-192777, JP-A-2001-301314, and the like can be used.

  The aqueous binder contained in the image receiving layer includes water-soluble polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, polyalkylene oxide, polyalkylene oxide derivatives, etc. Examples thereof include water-dispersible polymers such as polymers, styrene butadiene latexes, and acrylic emulsions. These aqueous binders can be used alone or in combination of two or more. In the present invention, among these, polyvinyl alcohol and silanol-modified polyvinyl alcohol are particularly preferable in terms of adhesion to the pigment and resistance to peeling of the ink receiving layer.

  The image receiving layer can contain a mordant, a water resistance agent, a light resistance improver, a gas resistance improver, a surfactant, a hardener and other additives in addition to the pigment and the aqueous binder.

The mordant added to the image receiving layer is preferably immobilized. For that purpose, a polymer mordant is preferably used.
For the polymer mordant, JP-A-48-28325, 54-74430, 54-124726, 55-22766, 55-142339, 60-23850, 60-23835, 60-23852, 60-23853, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60-122942, 60- No. 235134, JP-A-1-161236, U.S. Pat.Nos. 2,484,430, 2,548,564, 3,148,061, 3,309,690, 4,115,124, 4,124,386, 4,193,800, 4,273,853, 4,282,305, It is described in each specification of the same No. 4450224. An image receiving material containing a polymer mordant described in JP-A-1-161236, pages 212 to 215 is particularly preferred. When the polymer mordant described in the publication is used, an image with excellent image quality is obtained and the light resistance of the image is improved.

  The water-proofing agent is effective for making the image water-resistant. As these water-proofing agents, cationic resins are particularly desirable. Examples of such a cationic resin include polyamide polyamine epichlorohydrin, polyethyleneimine, polyamine sulfone, dimethyldiallylammonium chloride polymer, and cationic polyacrylamide. The content of these cationic resins is preferably 1 to 15% by mass, particularly 3 to 10% by mass, based on the total solid content of the ink receiving layer.

Examples of the light resistance improver and gas resistance improver include phenol compounds, hindered phenol compounds, thioether compounds, thiourea compounds, thiocyanate compounds, amine compounds, hindered amine compounds, TEMPO compounds, hydrazine compounds, hydrazide compounds, amidine compounds, Vinyl group-containing compounds, ester compounds, amide compounds, ether compounds, alcohol compounds, sulfinic acid compounds, saccharides, water-soluble reducing compounds, organic acids, inorganic acids, hydroxy group-containing organic acids, benzotriazole compounds, benzophenone compounds, triazine compounds , Heterocyclic compounds, water-soluble metal salts, organometallic compounds, metal complexes and the like.
Specific examples of these compounds include JP-A-10-182621, JP-A-2001-260519, JP-A-2000-260519, JP-B-4-34953, JP-B-4-34513, and JP-B-4-34512. , JP-A-11-170686, JP-A-60-67190, JP-A-7-276808, JP-A-2000-94829, JP-T 8-512258, JP-A-11-321090, etc. Can be given.

The surfactant functions as a coating aid, a peelability improver, a slippage improver or an antistatic agent. The surfactant is described in JP-A Nos. 62-173463 and 62-183457.
An organic fluoro compound may be used in place of the surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compound include a fluorine-based surfactant, an oily fluorine-based compound (eg, fluorine oil), and a solid fluorine compound resin (eg, tetrafluoroethylene resin). The organic fluoro compounds are described in JP-B-57-9053 (columns 8 to 17), JP-A-61-20994, and 62-135826.

  As the hardener, materials described in JP-A-1-161236, page 222, JP-A-9-263036, JP-A-10-119423, and JP-A-2001-310547 can be used.

  Examples of other additives added to the image receiving layer include pigment dispersants, thickeners, antifoaming agents, dyes, fluorescent whitening agents, preservatives, pH adjusters, matting agents, and hardening agents. The ink receiving layer may be one layer or two layers.

The recording paper and the recording film can be provided with a back coat layer, and examples of components that can be added to this layer include a white pigment, an aqueous binder, and other components.
Examples of white pigments contained in the backcoat layer include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, and aluminum silicate. , Diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrous halloysite, magnesium carbonate, magnesium hydroxide, white inorganic pigment, styrene And organic pigments such as polyethylene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins, and melamine resins.

  As the aqueous binder contained in the backcoat layer, styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxymethylcellulose Water-soluble polymers such as hydroxyethyl cellulose and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion. Examples of other components contained in the backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water-proofing agent.

  A polymer fine particle dispersion may be added to the constituent layers (including the back layer) of the inkjet recording paper and recording film. The polymer fine particle dispersion is used for the purpose of improving film properties such as dimensional stabilization, curling prevention, adhesion prevention, and film cracking prevention. The polymer fine particle dispersion is described in JP-A Nos. 62-245258, 62-136648, and 62-110066. When a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to a layer containing a mordant, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the back layer, curling can be prevented.

  The black ink of the present invention can also be used for purposes other than inkjet recording. For example, it can be used for display image materials, image forming materials for interior decoration materials, and image forming materials for outdoor decoration materials.

  Display image materials include posters, wallpaper, small decorative items (such as figurines and dolls), commercial flyers, wrapping paper, wrapping materials, paper bags, plastic bags, packaging materials, signs, transportation (automobiles, buses, trains, etc.) ) Refers to various things such as images drawn and attached to the side, clothes with logos, and so on. When the dye of the present invention is used as a material for forming a display image, the image includes all patterns of human-recognizable dyes such as abstract designs, characters, and geometric patterns in addition to images in a narrow sense.

  The interior decoration material refers to various items such as wallpaper, decorative accessories (such as figurines and dolls), lighting fixture members, furniture members, floor and ceiling design members. When the dye of the present invention is used as an image forming material, the image includes all patterns of dyes that can be recognized by humans such as abstract designs, characters, and geometric patterns in addition to images in a narrow sense.

  The outdoor decoration material refers to various materials such as wall materials, roofing materials, signboards, gardening materials, outdoor decoration accessories (such as figurines and dolls), and members of outdoor lighting equipment. When the dye of the present invention is used as an image forming material, the image includes not only images in a narrow sense but also all patterns of dyes that can be recognized by humans, such as abstract designs, characters, and geometric patterns.

  In the above applications, examples of media on which a pattern is formed include various materials such as paper, fiber, cloth (including non-woven fabric), plastic, metal, and ceramics. As the dyeing form, the dye can be fixed in the form of mordanting, printing, or a reactive dye having a reactive group introduced. Among these, it is preferable that the mordanting is performed.

In the production of ink, ultrasonic vibration can be applied to the dissolution process of additives such as dyes.
Ultrasonic vibration is a bubble created by applying ultrasonic energy equal to or higher than the energy received by the recording head in advance during the ink manufacturing process in order to prevent ink from generating bubbles due to the pressure applied by the recording head. Is to be removed.
The ultrasonic vibration is usually an ultrasonic wave having a frequency of 20 kHz or higher, preferably 40 kHz or higher, more preferably 50 kHz. The energy applied to the liquid by ultrasonic vibration is usually 2 × 10 ⁷ J / m ³ or more, preferably 5 × 10 ⁷ J / m ³ or more, more preferably 1 × 10 ⁸ J / m ³ or more. . Moreover, the application time of ultrasonic vibration is usually about 10 minutes to 1 hour.
The step of applying ultrasonic vibration shows an effect at any time after the dye is put into the medium. The effect is exhibited even if ultrasonic vibration is applied after the completed ink is once stored. However, adding ultrasonic vibration when the dye is dissolved and / or dispersed in the medium has a greater effect of removing bubbles, and the ultrasonic vibration promotes dissolution and / or dispersion of the dye in the medium. This is preferable.
That is, the step of applying at least ultrasonic vibration can be performed in any case, either during or after the step of dissolving and / or dispersing the dye in the medium. In other words, the step of applying at least the ultrasonic vibration can be arbitrarily performed once or more after the ink preparation until it becomes a product.
As an embodiment, the step of dissolving and / or dispersing in the medium preferably includes a step of dissolving the dye in a medium of a part of the entire medium and a step of mixing the remaining medium, and at least one of the above It is preferable to apply ultrasonic vibration to this step, and it is more preferable to apply at least ultrasonic vibration to the step of dissolving the dye in a part of the medium.
The step of mixing the remaining solvent may be a single step or a plurality of steps.
In addition, it is preferable to use heat degassing or vacuum degassing in combination with the ink production according to the present invention because the effect of removing bubbles in the ink is improved. The heating degassing step or the vacuum degassing step is preferably performed simultaneously with or after the step of mixing the remaining medium.
Examples of the ultrasonic vibration generating means in the step of applying ultrasonic vibration include known devices such as an ultrasonic disperser.

When producing the black ink of the present invention, a step of removing dust that is a solid content by filtration, which is performed after further preparation of liquid, is important. A filtration filter is used for this work. The filtration filter at this time is a filter having an effective diameter of 1 μm or less, preferably 0.3 μm or less and 0.05 μm or more, particularly preferably 0.3 μm or less and 0.25 μm or more. Use. Various materials can be used as the filter material, but in the case of water-soluble dye inks, it is preferable to use a filter prepared for an aqueous solvent. Among them, it is particularly preferable to use a filter made of a polymer material that hardly generates dust. As the filtration method, the solution may be passed through a solution, and either pressure filtration or vacuum filtration can be used.
After this filtration, air is often taken into the solution. Since bubbles caused by air often cause image disturbance in ink jet recording, it is preferable to separately provide the aforementioned defoaming step. As the defoaming method, the filtered solution may be allowed to stand, or various methods such as ultrasonic defoaming and vacuum defoaming using a commercially available apparatus can be used. In the case of defoaming with ultrasonic waves, the defoaming operation is preferably performed for about 30 seconds to 2 hours, more preferably about 5 minutes to 1 hour.
These operations are preferably performed using a space such as a clean room or a clean bench in order to prevent dust from entering during the operation. In the present invention, it is particularly preferable to perform this operation in a space of class 1000 or less as the degree of cleanliness. Here, “cleanness” refers to a value measured by a dust counter.

  In the present invention, the ink droplet volume on the recording material is from 0.1 pl to 100 pl. A preferable range of the droplet ejection volume is 0.5 pl or more and 50 pl or less, and a particularly preferable range is 2 pl or more and 50 pl or less.

In the present invention, there is no limitation on the ink jet recording method, and a known method, for example, a charge control method for ejecting ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) using vibration pressure of a piezo element, and the like. ), An acoustic ink jet system that converts electrical signals into acoustic beams, irradiates the ink and ejects ink using radiation pressure, and thermal ink jet (bubble jet) that uses the pressure generated by heating the ink to form bubbles ) Method.
Inkjet recording methods use a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different concentrations, and colorless and transparent inks. The method is included. The ink droplet volume is controlled mainly by the print head.

For example, in the case of the thermal ink jet method, the droplet ejection volume can be controlled by the structure of the print head. That is, droplets can be ejected in a desired size by changing the sizes of the ink chamber, the heating unit, and the nozzle. Even in the case of the thermal ink jet method, it is possible to realize droplet ejection of a plurality of sizes by providing a plurality of print heads having different heating parts and nozzle sizes.
In the case of the drop-on-demand method using a piezo element, the droplet ejection volume can be changed due to the structure of the print head as in the thermal ink jet method, but the waveform of the drive signal that drives the piezo element is controlled as described later. By doing so, droplets of a plurality of sizes can be ejected with a print head having the same structure.

In the present invention, the ejection frequency when ink is ejected onto a recording material is 1 KHz or more.
In order to record a high-quality image such as a photograph, it is necessary to set the droplet ejection density to 600 dpi (number of dots per inch) or more in order to reproduce a sharp image with small ink droplets.
On the other hand, when ink is ejected by a head having a plurality of nozzles, the number of heads that can be driven simultaneously is about several tens to 200 in the type in which the recording paper and the head move in a direction orthogonal to each other, and the line head There is a restriction that there are several hundreds even if the head is called a fixed type. This is because there are restrictions on driving power, and heat generated by the head affects the image, so that a large number of head nozzles cannot be driven simultaneously.
Here, the recording speed can be increased by increasing the drive frequency.
In the case of the thermal ink jet method, the droplet ejection frequency can be controlled by controlling the frequency of the head drive signal for heating the head.
In the case of the piezo method, this is possible by controlling the frequency of a signal for driving the piezo.
The driving of the piezo head will be described. For the image signal to be printed, the droplet size, droplet ejection speed, and droplet ejection frequency are determined by the printer control unit, and a signal for driving the print head is created. The drive signal is supplied to the print head. The droplet ejection size, droplet ejection speed, and droplet ejection frequency are controlled by a signal for driving the piezo. Here, the droplet ejection size and droplet ejection speed are determined by the shape and amplitude of the drive waveform, and the frequency is determined by the signal repetition period.
When this droplet ejection frequency is set to 10 kHz, the head is driven every 100 microseconds, and recording of one line is completed in 400 microseconds. By setting the moving speed of the recording paper to move 1/600 inch in 400 microseconds, that is, approximately 42 microns, it is possible to print at a speed of one sheet in 1.2 seconds.

With respect to the configuration of the printing apparatus and the configuration of the printer of the present invention, for example, a mode as disclosed in JP-A-11-170527 is preferable. For the ink cartridge, for example, the one disclosed in Japanese Patent Laid-Open No. 5-229133 is suitable. With respect to the suction and the configuration of a cap or the like that covers the print head at that time, for example, the one disclosed in JP-A-7-276671 is suitable. Further, it is preferable that a filter for eliminating bubbles as disclosed in JP-A-9-277552 is provided in the vicinity of the head.
The surface of the nozzle is preferably subjected to water repellent treatment as described in JP-A-2002-292878. The application may be a printer connected to a computer or an apparatus specialized for printing photographs.
In the ink jet recording method applied to the black ink of the present invention, it is preferable that the average droplet ejection speed when ejecting ink onto a recording material is 2 m / sec or more, preferably 5 m / sec or more.
The droplet ejection speed is controlled by controlling the shape and amplitude of the waveform that drives the head.
In addition, by using a plurality of drive waveforms properly, it is possible to eject droplets of a plurality of sizes with the same head.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this.
(Example 1-Use of the present dye alone)
After adding ultrapure water (resistance value 18 MΩ or more) to the following components to 20 ml, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, it filtered under reduced pressure with the micro filter with an average hole diameter of 0.25 micrometer, and prepared black ink AF.

Composition of black ink A b-8 1.5 g
(Λmax: 594 nm, W _{λ, 1/2} : 125 nm, Eox: 1.3 V)
Diethylene glycol 0.15g
Glycerin 2.25g
Diethylene glycol monobutyl ether 1.48g
2-pyrrolidone 0.73g
0.25 g of triethanolamine
AF-101 0.06g
Olfin E1010 0.15g
PROXEL XL2 0.05g

Composition of black ink B b-9 1.5 g
(Λmax: 597 nm, W _{λ, 1/2} : 125 nm, Eox: 1.32 V)
Diethylene glycol 1.48g
Glycerin 2.25g
Diethylene glycol monobutyl ether 1.48g
2-pyrrolidone 0.73g
0.25 g of triethanolamine
AF-101 0.06g
Olfin E1010 0.15g
PROXEL XL2 0.05g

Composition of black ink C b-10 1.5 g
(Λmax: 600 nm, W _{λ, 1/2} : 125 nm, Eox: 1.35 V)
Diethylene glycol 1.48g
Glycerin 2.25g
Diethylene glycol monobutyl ether 1.48g
2-pyrrolidone 0.73g
0.25 g of triethanolamine
AF-101 0.06g
Olfin E1010 0.15g
PROXEL XL2 0.05g

Composition of black ink D b-11 1.5 g
(Λmax: 575 nm, W _{λ, 1/2} : 125 nm, Eox: 1.3 V)
Diethylene glycol 1.48g
Glycerin 2.25g
Diethylene glycol monobutyl ether 1.48g
2-pyrrolidone 0.73g
0.25 g of triethanolamine
AF-101 0.06g
Olfin E1010 0.15g
PROXEL XL2 0.05g

  As shown in Table 10, as comparative inks, inks E and F were prepared in the same manner as in Example 1 using the dye b-7 in addition to the comparative dye 1 having the following structure.

Dye b-7
(Λmax: 588 nm, Wλ _{, 1/2} : 125 nm, Eox: 1.3 V)
Using the above dyes, inks shown in Table 10 below were prepared.

(Example 2-Combination with dye (s))
After adding ultrapure water (resistance value 18 MΩ or more) to the following components to 20 ml, the mixture was stirred for 1 hour while heating at 30 to 40 ° C. Then, it filtered under reduced pressure with the micro filter with an average hole diameter of 0.25 micrometer, and prepared black ink Bk-101.
[Bk-101 prescription]
(Solid content)
Black dye of the present invention (L: long wave side) (b-8) 1.5 g
_{(Λmax: 599nm, Wλ, 1} /2: 125nm, Eox: 1.3V)
Black dye (S: Short wave side) (BS-1) 0.5g
(Λmax: 462 nm)

Diethylene glycol 1.48g
Glycerin 2.25g
Diethylene glycol monobutyl ether 1.48g
2-pyrrolidone 0.73g
0.25 g of triethanolamine
AF-101 0.06g
Olfin E1010 0.15g
PROXEL XL2 0.05g

[Bk-102 prescription]
Bk-102 was prepared by preparing the same composition as in the Bk-101 formulation except that the black dye b-8 in the Bk-101 formulation was changed to b-9.

The oxidation potential (Eox) of the black dye (L: b-8 to 11) used here was determined by the measurement method described above and confirmed to be noble from 1.0 V (vs SCE).
[Bk-103-4 prescription]
Bk-103 to 4 were prepared in the same manner as the Bk-101 formulation except that the black dye b-8 of the Bk-101 formulation was changed to the following dye.
In addition, the following three types of dyes were used as comparative dyes.
1) Long wave side black dye (A) whose oxidation potential (Eox) is 1.0 V (vs SCE) or less (CI FOOD BLACK 2, Eox: 0.7 V)
2) Long wave side black dye having a half-value width (W _λ, 1/2) of diluted solution normalized spectrum of 95 nm and λmax of 580 nm (B)
3) Short-wave side black dye (C) having an oxidation potential (Eox) of 1.0 V (vs SCE) or less (CI DIRECT YELLOW 120)
The oxidation potential of the long wave side black dye (B) was 1.0 V (vs SCE) or less (Eox: 0.69 V).

The structure of comparative dye B is as follows.

  Using the above dyes, black inks shown in Table 11 below were prepared.

  Further, as a comparison type of ink, a PM-920C black ink cartridge manufactured by Epson Corporation was used.

  These inks are loaded into a black ink cartridge of an ink-jet printer PM-920C manufactured by EPSON, and other color inks are printed using PM-920C ink to print an image incorporating a gray image pattern and a character pattern. I let you. This includes a JIS code 2223 black square symbol printed at 48 points. Separately from this, the color tone of the image was visually evaluated using a test image chart of ISO / JIS 12640. The image receiving sheet was printed on photo glossy paper (PM photo paper <gloss> manufactured by EPSON Co., Ltd.) and inkjet paper photo glossy paper “Image” manufactured by Fuji Photo Film Co., Ltd., and image quality and image fastness were evaluated. .

(Image recording and evaluation)
The following evaluation was performed on the ink jet ink composed of the above inks and the comparative inks. The results are shown in Table 12. In Table 12, “paper dependency”, “water resistance”, “light resistance”, “dark heat storage stability”, and “ozone gas resistance” indicate that each ink-jet ink is an inkjet printer (EPSON Co., Ltd.). PM920C) was used for photo glossy paper (Epson's PM photographic paper <glossy>), and an image was evaluated by the following method.

<Paper dependence>
The color tone of the image formed on the photo glossy paper and the image separately formed on FUJIFILM photo glossy photographic paper and PPC plain paper are visually compared, and when the difference in color tone between the images is small, A (good), The case where the difference in color tone between images was large was evaluated as B (defect) and evaluated in two stages.
<Print density>
The maximum image density (ODmax) formed on the photo glossy paper was measured using a reflection densitometer (X-Rite 310TR), and the density values were compared.
<Absorbance difference (ΔD)>
Each ink was diluted with ultrapure water, an absorption spectrum was measured with a spectrophotometer using a cell having an optical path length of 1 cm, and λmax at that time was defined as D1. Further, the reflection spectrum of a sample recorded on photo glossy paper (PM gloss paper manufactured by EPSON Co., Ltd. <gloss>) was measured with an inkjet printer (manufactured by EPSON Corporation; PM920C), and λmax at that time was defined as D2. D1 and D2 The absolute value of the difference was calculated and used as the absorbance difference.

<Water resistance>
The photo glossy paper on which the image was formed was dried at room temperature for 1 hour, then immersed in deionized water for 10 seconds, and naturally dried at room temperature, and bleeding was observed. Evaluation was made in three stages, with A indicating no bleeding, B indicating slight bleeding, and C indicating large bleeding.
<Light resistance>
The photo glossy paper on which the image has been formed is irradiated with xenon light (85000 lx) for 7 days using a weatherometer (Atlas C.I65), and the image density before and after the xenon irradiation is measured by a reflection densitometer (X-Rite 310TR). And evaluated as a dye residual ratio. The reflection density was measured at three points of 1, 1.5 and 2.0.
The evaluation was made in three stages, with A being a dye residual ratio of 70% or more at any concentration, A being 1 or 2 points being less than 70% B, and C being less than 70% at all concentrations.
<Dark heat preservation>
The photo glossy paper on which the image was formed was stored for 7 days under conditions of 80 ° C. and 15% RH, and the image density before and after storage was measured using a reflection densitometer (X-Rite 310TR) and evaluated as a dye residual ratio. .
For the dye residual rate, the reflection density is evaluated at three points of 1, 1.5 and 2.0. When the dye residual rate is 90% or more at any concentration, A, 1 or 2 points are less than 90%. B, the case of less than 90% at all concentrations was set as C and evaluated in three stages.
<Ozone resistance>
The photo glossy paper on which the image is formed is left for 5 days in a box set at an ozone gas concentration of 0.5 to 0.1 ppm, room temperature, in a dark place, and the image density reflection density (X-Rite310TR) before and after being left under ozone gas. ) And evaluated as a dye residual ratio. The reflection density was evaluated at three points of 1, 1.5 and 2.0. The ozone gas concentration in the box was set using an ozone gas monitor (model: OZG-EM-01) manufactured by APPLICS. The evaluation was made in three stages, with A being a dye residual ratio of 70% or more at any concentration, A being 1 or 2 points being less than 70% B, and C being less than 70% at all concentrations.

As shown in the above table, it was found that the system using the black ink of the present invention was superior to the comparative example in all performances. Ink using a dye (b-8 to 11) in which at least one substituent X shown in the general formula (2) is substituted at the meta position with respect to the azo group linking part uses b-7. It was clear that the difference in absorbance was smaller than that of the inks used, the paper dependency was small, and the printing density was high, and it was found that all the performances including this point were superior.
Further, using inks A to D, an image was recorded on superfine glossy paper using an ink jet printer (PM-920C, manufactured by Seiko Epson Corporation). When the hue and light fastness of the obtained image were evaluated, the same results as in the above table were obtained.
Further, when comparing black images, it was found that the color balance of the image was greatly inferior after fading in the system (Bk-104) using the long wave side black dye (B).
Further, the reflection density (D _R , D _G , D _B ) of the three colors C (cyan), M (magenta), and Y (yellow) is measured for the pattern S using an X-rite 310TR density measuring device equipped with a status A filter. Was also measured at the same time. When the forced fading rate constants (k _R , k _G , k _B ) of the pattern S are obtained from this experiment, the ratio (R) between the maximum value and the minimum value is all 1 in the system using the black ink of the present invention. .05 or less. On the other hand, in Bk-103 to 4, all the ratios (R) were 1.25 or more, and it was found that the discoloration balance of the black image was greatly broken.
Also from this fact, the effect of the present invention is clear.
Further, the same ink prepared in Example 1 is packed in a cartridge of an ink jet printer BJ-F850 (manufactured by CANON), and an image is printed on the photo glossy paper GP-301 of the same printer, and the same evaluation as in Example 1 is performed. As a result, the same performance as in the above example was obtained.
In addition, the black ink of the present invention prepared by replacing the black dye with the other dye represented by the general formula (1) in the above-described example also obtained the same performance as in the above-described example.

Claims (8)

  A coloring composition comprising a dye having an oxidation potential of at least no less than 1.0 V (vs SCE) and an aqueous medium, wherein the dye has a λmax (D1) of the dye in the solution spectrum measurement of the coloring composition Coloring characterized in that the absolute value of the difference from λmax (D2) of the dye at a reflection density (0.9 to 1.1) measured after recording the coloring composition on a reflective medium is less than 14 nm Composition.   2. The dye according to claim 1, wherein the dye contains an aromatic group and a heterocyclic group, and contains at least one dye having a half-value width of 100 nm or more in an absorption spectrum of a diluted solution normalized to an absorbance of 1.0. Coloring composition.   The coloring composition according to claim 1 or 2, wherein the dye has a λmax of 500 nm to 700 nm. The coloring composition according to any one of claims 1 to 3, wherein the dye is a dye represented by the following general formula (1).

In the formula, A, B and C each independently represent an optionally substituted aromatic group or heterocyclic group. The coloring composition according to any one of claims 1 to 4, wherein the substituent A is represented by the following general formula (2) in the dye represented by the general formula (1).

Z represents an atomic group capable of forming an aromatic ring or an aromatic heterocyclic ring. X is a substituent capable of imparting water solubility, and at least one of the substituents is substituted with a ring directly bonded to the azo group. n is an integer of 1 or more.   A coloring composition comprising an aqueous medium containing at least one dye having an absorption spectrum λmax of 350 nm to 500 nm in an aqueous solution and at least one dye according to claim 1.   An ink-jet ink comprising the colored composition according to claim 1.   Using the colored composition according to claim 1, the inkjet ink according to claim 7, or an ink set comprising the colored composition or inkjet ink, image recording is performed by an inkjet printer. An inkjet recording method characterized by the above.