JP2005105095A - Cyan ink for inkjet and ink set for inkjet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cyan ink for inkjet which gives a cyan image excellent in weather resistance and print qualities in high-density printed parts, and an ink set. <P>SOLUTION: The ink for inkjet comprises at least one dye, dissolved or dispersed in an aqueous medium, having a λmax within the range of 580 to 700 nm and a light absorbance ratio of the light absorbance I(λmax+70 nm) at λmax+70 nm to the light absorbance I(λmax) at λmax, I(λmax+70 nm)/I(λmax), of at most 0.75. In the ink set comprising at least two kinds of the inks, the oxidation potential of the dye is heightened and ink solvents and dye solubility are rationalized, while a compulsory fading rate constant in an ozone atmosphere is caused to be at most 5.0×10<SP>-2</SP>[hour<SP>-1</SP>]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cyan ink for ink jet and an ink set for ink jet which are excellent in weather resistance of an image and image quality in a high density printing portion.

In recent years, 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 compositions for inkjet recording, water-based inks, oil-based inks, or solid (melted 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 inkjet 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, non-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 having a color index (CI) number are difficult to achieve both hue and fastness required for inkjet ink.

As an inkjet cyan ink, an ink using a phthalocyanine compound as a dye is known (for example, see Patent Documents 1 to 15).
When preparing these inks, water alone has poor permeability to media, and images are often not fixed. In addition, the liquid properties for ejecting ink as ink are often insufficient. For this reason, water-miscible high-boiling organic solvents are generally used as auxiliary solvents in the art.
Japanese Patent Laid-Open No. 2002-249677 JP 2002-256167 A JP 2002-275386 A JP 2002-285050 A JP 2002-294097 A JP 2002-302626 A JP 2002-309118 A JP 2002-327132 A JP 2003-3086 A JP 2003-3099 A Japanese Patent Laid-Open No. 2003-3109 JP 2003-12952 A Japanese Patent Laid-Open No. 2003-12956 JP 2003-64287 A JP 2003-119415 A

However, when the organic solvent is used in a large amount with respect to the dye, there is a problem that the fastness after printing of the pigment, that is, the weather resistance tends to be lowered. On the other hand, when the amount of the organic solvent is small relative to the dye, a cyan dye having good crystallinity is likely to precipitate in a high-density printing portion, and easily causes bronze gloss, which is a problem in this field.
In particular, in an ink set using a large number of inks when forming an image of one hue, an ink having a lower dye optical density (hereinafter referred to as a light ink) has a higher dye optical density. Since the ratio of the solvent to the dye is higher than that (hereinafter referred to as normal ink), this problem appears more remarkably.

  In view of the above circumstances, an object of the present invention is to provide an inkjet cyan ink and an inkjet ink set that provide a cyan image having excellent weather resistance of an image and printing quality in a high density printing portion.

The above problem is solved by the following means.
(1) A dye having an absorbance ratio I (λmax + 70 nm) / I (λmax) of λmax of 580 nm to 700 nm and an absorbance I (λmax) of λmax and an absorbance I (λmax + 70 nm) of λmax + 70 nm of 0.75 or less An inkjet cyan ink dissolved or dispersed in a seed, an aqueous medium, and after the ink is printed on a reflective medium, the reflection density (D _R ) in the cyan region measured through a status A filter is 0.90. A point of ˜1.10 is defined as the initial density of the ink, and this print is forcibly faded using an ozone fading tester capable of always generating 5 ppm of ozone, and the reflection density is initially set. inkjet Shian'i, wherein the forced fading rate constant obtained from the time until 80% of the concentration is 5.0 × 10 ^-2 [hour ^-1] or less Click.
(2) The cyan ink for inkjet according to (1), wherein the absorbance ratio I (λmax + 70 nm) / I (λmax) is 0.70 or less.
(3) The ink-jet cyan ink as described in (1) or (2) above, wherein the oxidation potential of the dye is nobler than 1.0 V (vs SCE).
(4) The ink-jet cyan ink as described in any one of (1) to (3) above, wherein the dye is a compound represented by the following general formula (1).
General formula (1)

In the general formula (1), X ₂₁ , X ₂₂ , X ₂₃ and X ₂₄ are each independently —SO—Z ₂ , —SO ₂ —Z ₂ , —SO ₂ NR ₂₁ R ₂₂ , a sulfo group, —CONR. ₂₁ R ₂₂ or —COOR ₂₁ is represented. Z ₂ each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or Represents a substituted or unsubstituted heterocyclic group. R ₂₁ and R ₂₂ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, substituted or unsubstituted It represents a substituted aryl group or a substituted or unsubstituted heterocyclic group.
Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ each independently represent a monovalent substituent.
_{a 21 ~a 24, b 21 ~b} 24 each represent the number of substituents of X ₂₁ to X ₂₄ and Y ₂₁ to Y _24. a _{21 to} a ₂₄ each independently represents a number of 0 to 4, but they are not all 0 at the same time. b ₂₁ ~b ₂₄ represents the number of independently 0-4. Incidentally, when a ₂₁ ~a ₂₄ and b ₂₁ ~b ₂₄ represents the number of 2 or more, plural X ₂₁ to X ₂₄ and Y ₂₁ to Y ₂₄ may be the same as or different from each other to each other.
M is a hydrogen atom, a metal atom or an oxide, hydroxide or halide thereof.

(5) The ink-jet cyan ink as described in (4) above, wherein the dye represented by the general formula (1) is a dye represented by the following general formula (2).
General formula (2)

In the general formula _{(2), X 51 ~X 54} , Y 51 ~Y 58, and M ₁ are the same meanings as defined _{X 21 ~X 24, Y 21 ~Y} 24, M in the general formula (1). a _{51 to} a ₅₄ each independently represents an integer of 1 or 2.

(6) The cyan ink according to any one of (1) to (5) above, wherein the ink set is an inkjet ink set including at least two types of cyan inks having different optical densities, and the forced fading according to (1) An inkjet ink set, wherein a cyan ink having a lower optical density has a lower speed constant than a cyan ink having a higher optical density.
(7) The ink set for inkjet according to any one of (1) to (5) above, wherein the ink is an inkjet ink set comprising at least two kinds of cyan inks having different optical densities, wherein the concentration of the water-soluble organic solvent contained in the ink However, an ink set for ink-jet recording is characterized in that a cyan ink having a low optical density is lower than a cyan ink having a high optical density.
(8) The cyan ink according to any one of (1) to (5) above, an inkjet ink set comprising at least two or more cyan inks having different optical densities, wherein the glycol organic solvent contained in the ink, The added solvent concentration when adding any two of the glycol alkyl ether organic solvent concentration and the amide organic solvent concentration is lower for cyan ink with lower optical density than for cyan ink with higher optical density. Ink-jet ink set characterized.

  ADVANTAGE OF THE INVENTION According to this invention, the cyan ink for inkjets and the inkjet ink set which give the cyan image excellent in the weather resistance of an image and the printing quality in a high density printing part can be provided.

Hereinafter, the present invention will be described in detail.
The ink-jet cyan ink of the present invention preferably has good fastness and good hue.
First, since the hue of cyan is good, it is particularly preferable that the tail on the long wave side is good in the absorption spectrum of the cyan dye. For this reason, the cyan dye used in the present invention has a λmax of 580 nm to 700 nm, and an absorbance ratio I (λmax + 70 nm) / I (λmax) between the absorbance I (λmax) of λmax and the absorbance I (λmax + 70 nm) of λmax + 70 nm is 0. .75 or less, preferably 0.70 or less.
In order to reduce the absorbance ratio, it is preferable to give the dye the following characteristics. That is, 1) The direction of the main transition spectrum is made constant (in the electron density distribution, the molecular structure in which the roles of donor and acceptor are clear) is taken. 2) To reduce the molecular mobility, adopt a molecular structure that is as rigid as possible (takes a structure that does not have a long, highly mobile substituent and has a ring fixed). 3) Increase the association and reduce the contribution of the monomer peak.

In the present invention, the following method is employed as a means for evaluating the fastness of the ink. First, after printing the ink on the reflective medium, the reflection density is measured through the status A filter, and one point where the reflection absorption density (D _R ) in the cyan region is 0.90 to 1.10. It is defined as the concentration. From this time (t) until the reflection density (D _R ) reaches 80% of the initial reflection density value, this print is forcibly faded using an ozone fading tester capable of always generating 5 ppm of ozone. The forced fading rate constant (k _R ) is obtained from the relational expression “0.8 = exp (−k _R · t)”. The speed constant in the present invention (k _R) is 5.0 × 10 ^-2 [hour ^-1] or less, preferably 1.0 × 10 ^-2 [hour ^-1] or less, more preferably 5.0 × 10 ^{- 3} Prepare an ink that will be [hour ^-1 ] or less.
In order to reduce the fading rate constant, it is preferable to have characteristics such as the dye used in the ink. That is, 1) It is difficult to be oxidized. Specifically, the oxidation potential described later is increased (an electron-withdrawing group is increased, an electron-deficient heterocycle is used, etc.). 2) Decrease the initial reactivity in the oxidation reaction (make sure there are no protons that are easily extracted, destabilize the cation radical, etc.). 3) Increase associative properties and reduce the frequency of oxidation per molecule (make molecular structure easy to associate). 4) To reduce the molecular mobility, adopt a molecular structure that is as rigid as possible (takes a structure in which no long substituents with high mobility are present and the ring is fixed).

  From the viewpoint of fastness of ink, particularly fastness to ozone gas, the cyan dye used in the present invention is preferably a dye having an oxidation potential nobler than 1.0 V (vs SCE), from 1.1 V (vs SCE). Are more preferred, and dyes that are noble above 1.2 V (vs SCE) are particularly preferred. As the kind of the dye, a phthalocyanine dye satisfying the above physical property requirements is particularly preferable.

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

Specifically, the oxidation potential is 1 × 10 ⁻⁴ 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 liters and measure as a value for SCE (saturated calomel electrode) using cyclic voltammetry or direct current polarography. 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, a direct current polarometer in dimethylformamide containing 0.1 moldm ^-3 tetrapropylammonium perchlorate as a supporting electrolyte (the concentration of the dye is 0.001 moldm ^-3 ). The value (vs SCE) measured by chromatography is taken as the oxidation potential of the dye.

  The value of Eox represents the ease of electron transfer from the sample to the electrode, and the greater the value (the higher the oxidation potential), the less electron transfer from the sample to the electrode, in other words, the less easily oxidized. In relation to the structure of the compound, the oxidation potential becomes more noble by introducing an electron withdrawing group, and the oxidation potential becomes lower by introducing an electron donating group. In the present invention, in order to lower the reactivity with ozone, which is an electrophile, it is desirable to introduce an electron withdrawing group into the cyan dye skeleton to make the oxidation potential more noble.

In the present invention, an ink set including at least two kinds of cyan inks having the above-described characteristics and different optical densities can be formed as an ink jet ink set.
In this case, when the forced fading speed constant is compared between the inks, the forced fading speed constant is smaller for cyan ink (light ink) having a lower optical density than for cyan ink (normal ink) having a higher optical density. It is preferable for suppressing bronze and the like and improving image quality.
Of the two or more cyan inks having different optical densities in the ink set, the highest density ink preferably contains 0.2 to 20 mass%, more preferably 0.5 to 15 mass% of the dye. To do. On the other hand, the low density ink is preferably in the range of 1/20 to 1/2, more preferably 1/10 to 3/7, with respect to the dye density of the highest density ink. It is.

Examples of cyan dyes suitable for the above purpose include phthalocyanine dyes represented by the general formula (1).
General formula (1)

In the general formula (1), X ₂₁ , X ₂₂ , X ₂₃ and X ₂₄ are each independently —SO—Z ₂ , —SO ₂ —Z ₂ , —SO ₂ NR ₂₁ R ₂₂ , a sulfo group, —CONR. ₂₁ R ₂₂ or —COOR ₂₁ is represented. Z ₂ each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or Represents a substituted or unsubstituted heterocyclic group. R ₂₁ and R ₂₂ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, substituted or unsubstituted It represents a substituted aryl group or a substituted or unsubstituted heterocyclic group.
Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ each independently represent a monovalent substituent.
_{a 21 ~a 24, b 21 ~b} 24 each represent the number of substituents of X ₂₁ to X ₂₄ and Y ₂₁ to Y _24. a _{21 to} a ₂₄ each independently represents a number of 0 to 4, but they are not all 0 at the same time. b ₂₁ ~b ₂₄ represents the number of independently 0-4. Incidentally, when a ₂₁ ~a ₂₄ and b ₂₁ ~b ₂₄ represents the number of 2 or more, plural X ₂₁ to X ₂₄ and Y ₂₁ to Y ₂₄ may be the same as or different from each other to each other.
M is a hydrogen atom, a metal atom or an oxide, hydroxide or halide thereof.

  Hereinafter, the dye that can be used in the present invention, including the general formula (1), will be described.

First, the phthalocyanine dye, which is a cyan dye, including the general formula (1) will be described in detail.
It is preferable that the phthalocyanine dye used in the present invention is excellent in both light resistance and ozone resistance and has a small change in hue and surface state (bronzing hardly occurs and dye does not easily precipitate).

  Regarding light resistance, when xenon light (Xe 1.1 W / m (intermittent condition)) was irradiated for 3 days with a TAC filter on a portion where the reflection density OD of the image printed on the Epson PM photographic receiving paper was 1.0 It is preferable that the dye residual ratio (reflection density after irradiation / initial density × 100) is 90% or more. Moreover, it is preferable that the dye residual rate at the time of 14 days is 85% or more.

Regarding the change in hue and surface state, the amount of Cu ions present as phthalate due to decomposition of the phthalocyanine dye serves as an index. It is preferable that the equivalent amount of Cu ions present in the actual print is 10 mg / m ² or less. The amount of Cu ions flowing out of the print is formed as a solid image with a Cu ion conversion amount of 20 mg / m ² or less. After this image is stored in a 5 ppm ozone environment for 24 hours and then faded by ozone, it flows out of the image into the water. The amount of Cu ions is preferably 20% or less. Prior to the fading, all Cu compounds are trapped in the image receiving material.

  The phthalocyanine dye having the physical properties as described above 1) increases the oxidation potential, 2) increases the association property, 3) introduces an association promoting group, and strengthens the hydrogen bond during π-π stacking. 4) It is obtained by not inserting a substitution machine at the α-position, that is, by making stacking easy.

The structural characteristics of the phthalocyanine dyes used in the present invention are the phthalocyanine dyes used in conventional inks derived from sulfonation of unsubstituted phthalocyanines, so the number and position of substituents are specified. Whereas the mixture cannot be used, a phthalocyanine dye capable of specifying the number and position of substituents is used.
The first structural feature is that the phthalocyanine dye does not go through sulfonation of unsubstituted phthalocyanine. The second structural feature is that it has an electron-withdrawing group at the β-position of the benzene ring of phthalocyanine, and particularly preferably has an electron-withdrawing group at the β-position of all benzene rings. Specifically, a sulfonyl group substituted (Japanese Patent Application Nos. 2001-47013 and 2001-190214), a sulfamoyl group generally substituted (Japanese Patent Application Nos. 2001-24352 and 2001-189882), and a heterocyclic sulfamoyl group Substituted one (Japanese Patent Application 2001-96610, Japanese Patent Application 2001-190216), one substituted with a heterocyclic sulfonyl group (Japanese Patent Application 2001-76689, Japanese Patent Application 2001-190215), one substituted with a specific sulfamoyl group (Japanese Patent Application 2001) -57063), those having a carbonyl group substituted (Japanese Patent Application No. 2002-012869), those having a specific substituent for solubility, improving ink stability, and measures against bronzing are preferred. Application 2002-012868), Li salt (Japanese Patent Application 2002-0) 2864), it is useful.

  The first characteristic feature is that it has a high oxidation potential (noble from 1.0 V). The second physical property is a strong associative property. Specific examples include those that define the association of oil-soluble dyes (Japanese Patent Application No. 2001-64413) and those that define the association of water-soluble dyes (Japanese Patent Application No. 2001-117350).

  Regarding the relationship between the number of associative groups and the performance (ink absorbance of the ink), the introduction of the associative groups tends to cause a decrease in absorbance and a shorter wavelength of λmax even in a dilute solution. The relationship between the number of associative groups and the performance (reflection density OD on Epson PM920 image receiving paper) is that the reflection density OD at the same ionic strength decreases as the number of associative groups increases. In other words, the meeting seems to proceed on the image receiving paper. Regarding the relationship between the number of associative groups and the performance (ozone resistance / light resistance), the greater the number of associative groups, the better the ozone resistance. Dyes with a large number of associative groups tend to improve light resistance. In order to impart ozone resistance, it is necessary to impart a substituent to the benzene ring of phthalocyanine. Since the reflection density OD and the robustness are in a trade-off relationship, it is necessary to increase the light resistance without weakening the association.

A preferred embodiment of the cyan ink using the phthalocyanine dye having the above characteristics is as follows.
1) Dye remaining when xenon light (Xe 1.1 W / m (intermittent condition)) is irradiated with a TAC filter for 3 days at a site where the reflection density OD of the image printed on the Epson PM photographic image receiving paper is 1.0 Cyan ink with a rate of 90% or more.
2) The pigment residual ratio when the portion where the reflection density in the status A filter of the printed image is 0.9 to 1.1 is stored in a 5 ppm ozone environment for 24 hours is 60% or more (preferably 80% or more). Cyan ink.
3) A cyan ink in which the amount of Cu ions flowing out into water after ozone fading is 2% or less of the total dye.
4) Cyan ink that can penetrate up to 30% or more of the upper part of the image receiving layer of the specific image receiving paper.

  Examples of the dye having the above characteristics include a phthalocyanine dye represented by the general formula (1).

Phthalocyanine dyes are known as fast dyes, but are known to be inferior in fastness to ozone gas when used as inkjet recording dyes.
In the present invention, as described above, it is desirable to introduce an electron withdrawing group into the phthalocyanine skeleton to make the oxidation potential nobler than 1.0 V (vs SCE). Therefore, by introducing a substituent having a large Hammett's substituent constant σp value (a measure of electron withdrawing property or electron donating property) such as a sulfinyl group, a sulfonyl group, or a sulfamoyl group, the oxidation potential can be made more noble. it can.
It is preferable to use the phthalocyanine dye represented by the general formula (1) also for the reason of adjusting the potential.

Hereinafter, the phthalocyanine dye represented by formula (1) will be described in detail.
In the general formula (1), X ₂₁ , X ₂₂ , X ₂₃ and X ₂₄ are each independently —SO—Z ₂ , —SO ₂ —Z ₂ , —SO ₂ NR ₂₁ R ₂₂ , a sulfo group, —CONR ₂₁ R ₂₂ or —CO ₂ R ₂₁ is represented. Among these substituents, —SO—Z ₂ , —SO ₂ —Z ₂ , —SO ₂ NR ₂₁ R ₂₂ and —CONR ₂₁ R ₂₂ are preferable, and —SO ₂ —Z ₂ and —SO ₂ NR ₂₁ R are particularly preferable. ₂₂ is preferred, and —SO ₂ —Z ₂ is most preferred. Here, when any of a _{21 to} a ₂₄ representing the number of substituents represents a number of 2 or more, a plurality of X _{21 to} X ₂₄ may be the same or different, and each of the above is independently described above. Represents any group of X ₂₁ , X ₂₂ , X ₂₃ and X ₂₄ may all be the same substituent, or, for example, X ₂₁ , X ₂₂ , X ₂₃ and X ₂₄ are all —SO ₂ —Z ₂ . And each Z ₂ includes different ones, which may be the same type of substituents but may be partially different from each other, or may be different from each other (for example, —SO ₂ —Z ₂ and it may include -SO ₂ NR ₂₁ R _22).

Z ₂ is each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, Represents a substituted or unsubstituted heterocyclic group. Preferred are a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. Among them, a substituted alkyl group, a substituted aryl group, and a substituted heterocyclic group are most preferred.

R ₂₁ and R ₂₂ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, substituted or unsubstituted It represents an unsubstituted aryl group or a substituted or unsubstituted heterocyclic group. Of these, a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group are preferable. Among them, a hydrogen atom, a substituted alkyl group, a substituted aryl group, and a substituted heterocyclic group are preferable. A cyclic group is more preferable. However, it is not preferred that both R ₂₁ and R ₂₂ are hydrogen atoms.

The substituted or unsubstituted alkyl group represented by R ₂₁ , R ₂₂ and Z ₂ is preferably an alkyl group having 1 to 30 carbon atoms. In particular, a branched alkyl group is preferred because of increasing the solubility of the dye and the ink stability, and particularly preferred is a case having an asymmetric carbon (use in a racemic form). Examples of the substituent include the same substituents as those described later when Z ₂ , R ₂₁ , R ₂₂ , Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ can further have a substituent. Of these, a hydroxyl group, an ether group, an ester group, a cyano group, an amide group, and a sulfonamide group are particularly preferable because they enhance the association of the dye and improve the fastness. In addition, you may have a halogen atom and an ionic hydrophilic group. The number of carbon atoms of the alkyl group does not include the carbon atom of the substituent, and the same applies to other groups.

The substituted or unsubstituted cycloalkyl group represented by R ₂₁ , R ₂₂ and Z ₂ is preferably a cycloalkyl group having 5 to 30 carbon atoms. In particular, the case of having an asymmetric carbon (use in a racemic form) is particularly preferable because of increasing the solubility of the dye and the ink stability. Examples of the substituent include the same substituents as those described later when Z ₂ , R ₂₁ , R ₂₂ , Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ can further have a substituent. Among these, a hydroxyl group, an ether group, an ester group, a cyano group, an amide group, and a sulfonamide group are particularly preferable because they increase the association property of the dye and improve the fastness. In addition, you may have a halogen atom and an ionic hydrophilic group.

The substituted or unsubstituted alkenyl group represented by R ₂₁ , R ₂₂ and Z ₂ is preferably an alkenyl group having 2 to 30 carbon atoms. In particular, a branched alkenyl group is preferred because it increases the solubility of the dye and the ink stability, and particularly preferred is a case having an asymmetric carbon (use in a racemic form). Examples of the substituent include the same substituents as those described later when Z ₂ , R ₂₁ , R ₂₂ , Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ can further have a substituent. Among these, a hydroxyl group, an ether group, an ester group, a cyano group, an amide group, and a sulfonamide group are particularly preferable because they increase the association property of the dye and improve the fastness. In addition, you may have a halogen atom and an ionic hydrophilic group.

The substituted or unsubstituted aralkyl group represented by R ₂₁ , R ₂₂ and Z ₂ is preferably an aralkyl group having 7 to 30 carbon atoms. In particular, a branched aralkyl group is preferred because it increases the solubility of the dye and the ink stability, and particularly preferred is a case having an asymmetric carbon (use in a racemic form). Examples of the substituent include the same substituents as those described later when Z ₂ , R ₂₁ , R ₂₂ , Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ can further have a substituent. Among these, a hydroxyl group, an ether group, an ester group, a cyano group, an amide group, and a sulfonamide group are particularly preferable because they increase the association property of the dye and improve the fastness. In addition, you may have a halogen atom and an ionic hydrophilic group.

The substituted or unsubstituted aryl group represented by R ₂₁ , R ₂₂ and Z ₂ is preferably an aryl group having 6 to 30 carbon atoms. Examples of the substituent include the same substituents as those described later when Z ₂ , R ₂₁ , R ₂₂ , Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ can further have a substituent. Among these, an electron-withdrawing group is particularly preferable because the oxidation potential of the dye is noble and fastness is improved. Examples of the electron-withdrawing group include those having a positive Hammett's substituent constant σp value. Among them, a halogen atom, a heterocyclic group, a cyano group, a carboxyl group, an acylamino group, a sulfonamido group, a sulfamoyl group, a carbamoyl group, a sulfonyl group, an imide group, an acyl group, a sulfo group, and a quaternary ammonium group are preferable, and a cyano group , Carboxyl group, sulfamoyl group, carbamoyl group, sulfonyl group, imide group, acyl group, sulfo group, and quaternary ammonium group are more preferable.

The heterocyclic group represented by R ₂₁ , R ₂₂ and Z ₂ is preferably a 5-membered or 6-membered ring, and they may be further condensed. Further, it may be an aromatic heterocyclic ring or a non-aromatic heterocyclic ring. In the following, the heterocyclic group represented by R ₂₁ , R ₂₂ and Z ₂ is exemplified in the form of a heterocyclic ring with the substitution position omitted, but the substitution position is not limited. For example, if it is pyridine, Substitution at the 2nd, 3rd and 4th positions is possible. Pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole, indole, furan, benzofuran, thiophene, benzothiophene, pyrazole, imidazole, benzimidazole, triazole, oxazole, benzoxazole, thiazole Benzothiazole, isothiazole, benzisothiazole, thiadiazole, isoxazole, benzisoxazole, pyrrolidine, piperidine, piperazine, imidazolidine, thiazoline and the like. Among them, an aromatic heterocyclic group is preferable, and preferable examples thereof are exemplified in the same manner as described above. Pyridine, pyrazine, pyrimidine, pyridazine, triazine, pyrazole, imidazole, benzimidazole, triazole, thiazole, benzothiazole, isothiazole, benz Examples include isothiazole and thiadiazole.
They may have a substituent, and as examples of the substituent, Z ₂ , R ₂₁ , R ₂₂ , Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ described later can further have a substituent. In this case, the same substituents as those described above can be used. Preferred substituents are the same as those of the aryl group, and more preferred substituents are the same as the more preferred substituent of the aryl group.

Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ are each independently a hydrogen atom, halogen atom, alkyl group, cycloalkyl group, alkenyl group, aralkyl group, aryl group, heterocyclic group, cyano group, hydroxyl group, nitro Group, amino group, alkylamino group, alkoxy group, aryloxy group, acylamino group, arylamino group, ureido group, sulfamoylamino group, alkylthio group, arylthio group, alkoxycarbonylamino group, sulfonamido group, carbamoyl group, Sulfamoyl group, sulfonyl group, alkoxycarbonyl group, heterocyclic oxy group, azo group, acyloxy group, carbamoyloxy group, silyloxy group, aryloxycarbonyl group, aryloxycarbonylamino group, imide group, heterocyclic thio group, phosphoryl group, Acyl group, carboxy It can be exemplified group or a sulfo group, each of which may further have a substituent.
Among these, a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cyano group, an alkoxy group, an amide group, a ureido group, a sulfonamide group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, a carboxyl group, and a sulfo group are preferable. In particular, a hydrogen atom, a halogen atom, a cyano group, a carboxyl group and a sulfo group are preferable, and a hydrogen atom is most preferable.

When Z ₂ , R ₂₁ , R ₂₂ , Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ are groups that can further have a substituent, they may further have the following substituents.
A linear or branched alkyl group having 1 to 12 carbon atoms, a linear or branched aralkyl group having 7 to 18 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, and a linear chain having 2 to 12 carbon atoms Or a branched alkynyl group, a linear or branched cycloalkyl group having 3 to 12 carbon atoms, a linear or branched cycloalkenyl group having 3 to 12 carbon atoms (the above groups having a branched chain are dissolved in the dye) Preferred are those having an asymmetric carbon, and particularly preferred are those having an asymmetric carbon, such as methyl, ethyl, propyl, isopropyl, sec-butyl, t-butyl, 2- Ethylhexyl, 2-methylsulfonylethyl, 3-phenoxypropyl, trifluoromethyl, cyclopentyl), halogen atom (eg, chlorine atom, bromine atom), aryl group (For example, phenyl, 4-t-butylphenyl, 2,4-di-t-amylphenyl), a heterocyclic group (for example, imidazolyl, pyrazolyl, triazolyl, 2-furyl, 2-thienyl, 2-pyrimidinyl, 2- Benzothiazolyl), cyano group, hydroxyl group, nitro group, carboxy group, amino group, alkyloxy group (for example, methoxy, ethoxy, 2-methoxyethoxy, 2-methanesulfonylethoxy), aryloxy group (for example, phenoxy, 2- Methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 3-t-butyloxycarbamoylphenoxy, 3-methoxycarbamoyl), acylamino groups (for example, acetamide, benzamide, 4- (3-t-butyl-4-) Hydroxyphenoxy) butanamide), alkyl An amino group (eg, methylamino, butylamino, diethylamino, methylbutylamino), an anilino group (eg, phenylamino, 2-chloroanilino), a ureido group (eg, phenylureido, methylureido, N, N-dibutylureido), Sulfamoylamino group (for example, N, N-dipropylsulfamoylamino), alkylthio group (for example, methylthio, octylthio, 2-phenoxyethylthio), arylthio group (for example, phenylthio, 2-butoxy-5-t-) Octylphenylthio, 2-carboxyphenylthio), alkyloxycarbonylamino groups (eg methoxycarbonylamino), sulfonamido groups (eg methanesulfonamide, benzenesulfonamide, p-toluenesulfonamide), cal Moyl group (for example, N-ethylcarbamoyl, N, N-dibutylcarbamoyl), sulfamoyl group (for example, N-ethylsulfamoyl, N, N-dipropylsulfamoyl, N-phenylsulfamoyl), sulfonyl group ( For example, methanesulfonyl, octanesulfonyl, benzenesulfonyl, toluenesulfonyl), alkyloxycarbonyl group (for example, methoxycarbonyl, butyloxycarbonyl), heterocyclic oxy group (for example, 1-phenyltetrazol-5-oxy, 2-tetrahydropyrani) Oxy), azo group (for example, phenylazo, 4-methoxyphenylazo, 4-pivaloylaminophenylazo, 2-hydroxy-4-propanoylphenylazo), acyloxy group (for example, acetoxy), carbamoyloxy group (Eg, N-methylcarbamoyloxy, N-phenylcarbamoyloxy), silyloxy groups (eg, trimethylsilyloxy, dibutylmethylsilyloxy), aryloxycarbonylamino groups (eg, phenoxycarbonylamino), imide groups (eg, N- Succinimide, N-phthalimide), heterocyclic thio group (for example, 2-benzothiazolylthio, 2,4-di-phenoxy-1,3,5-triazole-6-thio, 2-pyridylthio), sulfinyl group (for example, 3-phenoxypropylsulfinyl), phosphonyl groups (eg phenoxyphosphonyl, octyloxyphosphonyl, phenylphosphonyl), aryloxycarbonyl groups (eg phenoxycarbonyl), acyl groups (eg acetyl, 3-phenylpropyl) Panoiru, benzoyl), ionic hydrophilic groups (e.g., carboxyl group, a sulfo group, a phosphono group and a quaternary ammonium group).

When the phthalocyanine dye represented by the general formula (1) is water-soluble, it preferably has an ionic hydrophilic group. Examples of the ionic hydrophilic group 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).
Among the counter ions, an alkali metal salt is preferable, and a lithium salt is particularly preferable because it increases the solubility of the dye and improves the ink stability.

  The number of ionic hydrophilic groups is preferably at least two in one molecule of phthalocyanine dye, and particularly preferably at least two sulfo groups and / or carboxyl groups.

In the general formula (1), a ₂₁ ~a ₂₄ and b ₂₁ ~b ₂₄ each represent the number of substituents of X ₂₁ to X ₂₄ and Y ₂₁ to Y _24. a _{21 to} a ₂₄ each independently represents an integer of 0 to 4, but they are not all 0 at the same time. b ₂₁ ~b ₂₄ each independently represents an integer of 0-4. When any of a _{21 to} a ₂₄ and b _{21 to} b ₂₄ is an integer of 2 or more, any one of X _{21 to} X ₂₄ and Y _{21 to} Y ₂₄ is present, May be the same as or different from each other.

a ₂₁ and b ₂₁ satisfy the relationship a ₂₁ + b ₂₁ = 4. Particularly preferred, a ₂₁ represents 1 or 2, a combination of b ₂₁ represents 3 or 2, Among them, a ₂₁ represents 1, b ₂₁ are the most preferred combination representing the three.

Each combination of a ₂₂ and b ₂₂ , a ₂₃ and b ₂₃ , and a ₂₄ and b ₂₄ has the same relationship as the combination of a ₂₁ and b ₂₁ , and a preferable combination is also the same.

M represents a hydrogen atom, a metal element or an oxide, hydroxide or halide thereof.
What is preferable as M is a metal element other than a hydrogen atom, such as Li, Na, K, Mg, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi and the like can be mentioned.
Preferred examples of the oxide include VO and GeO.

Moreover, as a hydroxide, Si (OH) ₂ , Cr (OH) ₂ , Sn (OH) _2, etc. are mentioned preferably.

Further, examples of the halide include AlCl, SiCl ₂ , VCl, VCl ₂ , VOCl, FeCl, GaCl, and ZrCl.

  Of these, Cu, Ni, Zn, Al and the like are preferable, and Cu is most preferable.

  In addition, in the phthalocyanine dye represented by the general formula (1), Pc (phthalocyanine ring) is a dimer (for example, Pc-MLM-Pc) or 3 via L (a divalent linking group). A monomer may be formed, and M at that time may be the same or different.

In this case, the divalent linking group represented by L is an oxy group —O—, a thio group —S—, a carbonyl group —CO—, a sulfonyl group —SO ₂ —, an imino group —NH—, or a methylene group —CH. _2- and the groups formed by combining these are preferred.

  As for the preferred combination of substituents of the compound represented by the general formula (1), a compound in which at least one of various substituents is the above preferred group is preferred, and more various substituents are the above preferred groups. Compounds are more preferred, and compounds in which all substituents are the preferred groups are most preferred.

Among the phthalocyanine dyes represented by the general formula (1), a phthalocyanine dye having a structure represented by the general formula (2) is more preferable. Hereinafter, the phthalocyanine dye represented by the general formula (2) will be described in detail.
General formula (2)

In the general formula _{(2), X 51 ~X 54} , Y 51 ~Y 58 is the general formula _{X 21 ~X 24, Y 21 ~Y} 24 in (1) the same meanings, and preferred examples are also the same . Further, M ₁ is the general formula (1) have the same meaning as M, preferred examples are also the same.

In the general formula (2), a _{51 to} a ₅₄ are each independently an integer of 1 or 2, preferably satisfy 4 ≦ a ₅₁ + a ₅₂ + a ₅₃ + a ₅₄ ≦ 6, and particularly preferably a ₅₁ = a _{This is when 52} = a ₅₃ = a ₅₄ = 1.

X ₅₁ , X ₅₂ , X ₅₃ and X ₅₄ may each be exactly the same substituent, or, for example, X ₅₁ , X ₅₂ , X ₅₃ and X ₅₄ are all —SO ₂ —Z ₂ and each As in the case where Z ₂ includes different ones, they may be the same type of substituents but may be partially different from each other, or different from each other, for example, —SO ₂ —Z ₂ and —SO _{2. 2} NR ₂₁ R ₂₂ may be included.

Among the phthalocyanine dyes represented by the general formula (2), particularly preferred combinations of substituents are as follows.
X _{51 to} X ₅₄ are each independently preferably —SO—Z ₂ , —SO ₂ —Z ₂ , —SO ₂ NR ₂₁ R ₂₂ or —CONR ₂₁ R ₂₂ , and in particular —SO ₂ —Z ₂ or — SO ₂ NR ₂₁ R ₂₂ is preferred, and —SO ₂ —Z ₂ is most preferred.

Z ₂ is preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and most preferably a substituted alkyl group, a substituted aryl group, or a substituted heterocyclic group. . In particular, the case of having an asymmetric carbon in the substituent (use in a racemic form) is preferable because of increasing the solubility of the dye and the ink stability. In addition, for the reason of increasing the association property and improving the fastness, it is preferable that a hydroxyl group, an ether group, an ester group, a cyano group, an amide group, or a sulfonamide group have in the substituent.

R ₂₁ and R ₂₂ are each independently preferably a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, and among them, a hydrogen atom and a substituted alkyl A group, a substituted aryl group, and a substituted heterocyclic group are more preferable. However, it is not preferred that both R ₂₁ and R ₂₂ are hydrogen atoms. In particular, the case of having an asymmetric carbon in the substituent (use in a racemic form) is preferable because of increasing the solubility of the dye and the ink stability. In addition, for the reason of increasing the association property and improving the fastness, it is preferable that a hydroxyl group, an ether group, an ester group, a cyano group, an amide group, or a sulfonamide group have in the substituent.

Y _{51 to} Y ₅₈ are each independently a hydrogen atom, halogen atom, alkyl group, aryl group, cyano group, alkoxy group, amide group, ureido group, sulfonamido group, carbamoyl group, sulfamoyl group, alkoxycarbonyl group, carboxyl And a sulfo group are preferable, and a hydrogen atom, a halogen atom, a cyano group, a carboxyl group, or a sulfo group is particularly preferable, and a hydrogen atom is most preferable.

a _{51 to} a ₅₄ are each independently preferably 1 or 2, and particularly preferably all 1.

M ₁ represents a hydrogen atom, a metal element or an oxide, hydroxide or halide thereof, particularly Cu, Ni, Zn, and Al, and particularly Cu is most preferable.

When the phthalocyanine dye represented by the general formula (2) is water-soluble, it preferably has an ionic hydrophilic group. Examples of the ionic hydrophilic group 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).
Among the counter ions, an alkali metal salt is preferable, and a lithium salt is particularly preferable because it increases the solubility of the dye and improves the ink stability.

  As the number of ionic hydrophilic groups, it is preferable to have at least two phthalocyanine dye molecules, and it is particularly preferable to have at least two sulfo groups and / or carboxyl groups.

  As for the preferred combination of substituents of the compound represented by the general formula (2), a compound in which at least one of various substituents is the above preferred group is preferred, and more various substituents are the above preferred groups. Compounds are more preferred, and compounds in which all substituents are the preferred groups are most preferred.

  The chemical structure of the phthalocyanine dye represented by the general formula (2) includes at least one electron-withdrawing group such as a sulfinyl group, a sulfonyl group, and a sulfamoyl group on each of the four benzene rings of the phthalocyanine, It is preferable to introduce so that the total of the σp values of the substituents may be 1.6 or more.

  Here, Hammett's substituent constant σp value will be described briefly. Hammett's rule is a method described in 1935 by L. E. 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 (Mc Graw-Hill) and “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, dyes used in the present invention include those that are not benzene derivatives, but the σp value is used as a measure of the electronic effect of the substituent regardless of the substitution position. In the present invention, the σp value is used in this sense.

The phthalocyanine dye represented by the general formula (1) inevitably has different introduction positions and introduction numbers of substituents Xn (n = 1 to 4) and Ym (m = 1 to 4) depending on the synthesis method. Mixtures are common, so the general formula often represents a statistical average of these analog mixtures. In the present invention, it has been found that a specific mixture is particularly preferable when these analog mixtures are classified into the following three types. That is, the phthalocyanine dye analog mixture represented by the general formulas (1) and (2) is defined by being classified into the following three types based on the substitution positions. Y ₅₁ , Y ₅₂ , Y ₅₃ , Y ₅₄ , Y ₅₅ , Y ₅₆ , Y ₅₇ , Y ₅₈ in the general formula (2) are respectively in the 1, 4, 5, 8, 9, 12, 13, 16 position. To do.

(1) β-position substitution type: phthalocyanine dye having a specific substituent at the 2 and / or 3 position, 6 and / or 7 position, 10 and / or 11 position, 14 and / or 15 position.
(2) α-position substitution type: phthalocyanine dye having a specific substituent at 1 and / or 4 position, 5 and / or 8 position, 9 and / or 12 position, 13 and / or 16 position.
(3) α, β-position mixed substitution type: a phthalocyanine dye having a specific substituent without regularity at positions 1 to 16.

  In the present specification, when describing derivatives of phthalocyanine dyes having different structures (particularly, different substitution positions), the β-position substitution type, α-position substitution type, and α, β-position mixed substitution type are used. .

  Examples of the phthalocyanine dye used in the present invention include “Phthalocyanine—Chemistry and Function” (P. 1-62), C.I. C. Leznoff-A. B. P. Lever co-authored, published by VCH, “Phthalogicanes-Properties and Applications” (P. 1-54), etc., can be synthesized by combining quoted or similar methods.

  The phthalocyanine dye represented by the general formula (1) of the present invention is described in International Publication Nos. 00/17275, 00/08103, 00/08101, 98/41853, and JP-A-10-36471. As described above, for example, it can be synthesized through sulfonation, sulfonyl chlorideation, and amidation reaction of an unsubstituted phthalocyanine compound. In this case, sulfonation can occur at any position of the phthalocyanine nucleus, and the number of sulfonation is difficult to control. Therefore, when a sulfo group is introduced under such reaction conditions, the position and number of the sulfo group introduced into the product cannot be specified, and a mixture in which the number of substituents and the substitution position are different is always given. Therefore, since the number and position of the heterocyclic-substituted sulfamoyl group cannot be specified when synthesizing it as a raw material, the resulting phthalocyanine dye includes α, β-, which includes several kinds of compounds having different numbers and positions of substituents. It is obtained as a coordinate mixed substitution type mixture.

  As described above, for example, when a large number of electron withdrawing groups such as sulfamoyl groups are introduced into the phthalocyanine nucleus, the oxidation potential becomes more noble and the ozone resistance is enhanced. According to the above synthesis method, it is inevitable that a small amount of electron-withdrawing groups are introduced, that is, a phthalocyanine dye having a lower oxidation potential is mixed. Therefore, in order to improve ozone resistance, it is more preferable to use a synthesis method that suppresses the formation of a compound having a lower oxidation potential.

  The phthalocyanine compound represented by the general formula (2) of the present invention is, for example, a phthalonitrile derivative (compound P) and / or a diiminoisoindoline derivative (compound Q) represented by the following formula represented by the general formula (3). Or a tetrasulfophthalocyanine compound obtained by reacting a 4-sulfophthalonitrile derivative (compound R) represented by the following formula with a metal derivative represented by the following general formula (3): Can be guided.

In the above formulas, Xp corresponds to X ₅₁ , X ₅₂ , X ₅₃ or X ₅₄ in the general formula (2). Yq and Yq ′ correspond to Y ₅₁ , Y ₅₂ , Y ₅₃ , Y ₅₄ , Y ₅₅ , Y ₅₆ , Y ₅₇ or Y ₅₈ in the general formula (2), respectively. In compound R, M ′ represents a cation.

  Examples of the cation represented by M ′ include alkali metal ions such as Li, Na, and K, or organic cations such as triethylammonium ion and pyridinium ion.

  General formula (3): M- (Y) d

In general formula (3), M has the same meaning as M ₁ M, and the general formula (2) of the formula (1), Y is a halogen atom, acetate anion, acetyl acetonate, monovalent, such as oxygen Or a bivalent ligand is shown, d is an integer of 1-4.

  That is, according to the above synthesis method, a specific number of desired substituents can be introduced. In particular, when a large number of electron withdrawing groups are to be introduced in order to make the oxidation potential noble as in the present invention, the above synthesis method is the method already described for synthesizing the phthalocyanine compound of the general formula (1). It is extremely superior compared to

  The phthalocyanine compound represented by the general formula (2) thus obtained is usually a mixture of compounds represented by the following general formulas (a) -1 to (a) -4 which are isomers at each substitution position of Xp. That is, the β-position substitution type.

In the above synthesis method, if the same Xp is used, a β-position substituted phthalocyanine dye in which X ₅₁ , X ₅₂ , X ₅₃ and X ₅₄ are the same substituents can be obtained. On the other hand, by using different combinations of Xp, it is possible to synthesize dyes having the same type of substituents but partially different from each other, or dyes having different types of substituents. . Among the dyes of the general formula (2), these dyes having different electron-withdrawing substituents are particularly preferable because the solubility of the dye, the association property, the stability with time of the ink, and the like can be adjusted.

  In the present invention, it is found that it is very important to improve the fastness that the oxidation potential is noble than 1.0 V (vs SCE) in any substitution type. It was completely unpredictable from the prior art. Although the cause is unknown in detail, the β-position substitution type is clearly superior in terms of hue, light fastness, ozone gas resistance, etc. than the α, β-position mixed substitution type. there were.

  Specific examples of the phthalocyanine dyes represented by the general formulas (1) and (2) (Exemplary compounds I-1 to I-12 and 101 to 190) are shown below. The phthalocyanine dyes used in the present invention are as follows. It is not limited to the example.

  In addition, the structure of the phthalocyanine compound shown by M-Pc (Xp1) m (Xp2) n of compound Nos. 146 to 190 is as follows.

  The phthalocyanine dye represented by the general formula (1) can be synthesized according to the aforementioned patent. Further, the phthalocyanine dye represented by the general formula (2) is not limited to the synthesis method described above, and JP-A Nos. 2001-226275, 2001-96610, 2001-47013, and 2001-193638. It can be synthesized by the method described in 1. Further, the starting material, the dye intermediate and the synthesis route are not limited to these.

  The content of the phthalocyanine dye represented by the general formula (1) in the ink is preferably 0.2 to 20% by mass, and more preferably 0.5 to 15% by mass.

  In the ink and ink set of the present invention, other dyes may be used in combination with the above dyes in order to obtain a full-color image or to adjust the color tone. The following can be mentioned as an example of the dye which can be used together.

  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.
Also, black dyes such as polyazo dyes can 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
CI 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
CI Direct Violet 7, 9, 47, 48, 51, 66, 90, 93, 94, 95, 98, 100, 101
CI 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
CI 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
CI 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
CI 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
CI Acid Violet 5, 34, 43, 47, 48, 90, 103, 126
CI 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
CI 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
CI Acid Black 7, 24, 29, 48, 52: 1, 172
CI Reactive Red 3, 13, 17, 19, 21, 22, 23, 24, 29, 35, 37, 40, 41, 43, 45, 49, 55
CI Reactive Violet 1, 3, 4, 5, 6, 7, 8, 9, 16, 17, 22, 23, 24, 26, 27, 33, 34
CI Reactive Yellow 2, 3, 13, 14, 15, 17, 18, 23, 24, 25, 26, 27, 29, 35, 37, 41, 42
CI Reactive Blue 2, 3, 5, 8, 10, 13, 14, 15, 17, 18, 19, 21, 25, 26, 27, 28, 29, 38
CI Reactive Black 4, 5, 8, 14, 21, 23, 26, 31, 32, 34
CI Basic Red 12, 13, 14, 15, 18, 22, 23, 24, 25, 27, 29, 35, 36, 38, 39, 45, 46
CI Basic Violet 1, 2, 3, 7, 10, 15, 16, 20, 21, 25, 27, 28, 35, 37, 39, 40, 48
CI Basic Yellow 1, 2, 4, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 39, 40
CI Basic Blue 1, 3, 5, 7, 9, 22, 26, 41, 45, 46, 47, 54, 57, 60, 62, 65, 66, 69, 71
CI Basic Black 8, etc.

Furthermore, a pigment can be used in combination.
As the pigment that can be used in the ink of the present invention, commercially available pigments and known pigments described in various documents can be used. Regarding the literature, the Color Index (Edited by The Society of Dyers and Colorists), “Revised New Handbook of Pigments” edited by the Japan Pigment Technology Association (published in 1989), “Latest Pigment Applied Technology” published by CMC (published in 1986), “Printing Ink Technology” CMC Publication (1984), Industrial Organic Pigments (VCH Verlagsgesellschaft, 1993) by W. Herbst and K. Hunger. 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. CI Pigment Yellow 34, 37, 42, 53 for yellow pigments, CI Pigment Red 101, 108 for red pigments, CI Pigment Blue 27, 29, 17: 1 for blue pigments, CI Pigment Black for black pigments 7, CI Pigment White 4, 6, 18, 21, etc. of white pigments such as magnetite.

  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), a dyed lake pigment-based triarylcarbonium pigment are preferable for blue to cyan pigments, and in particular phthalocyanine. Pigments (preferred examples include copper phthalocyanine such as CI Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4, and 15: 6, monochloro or low chlorinated copper phthalocyanine, and arnium phthalocyanine. Pigment described in European Patent No. 860475, metal-free phthalocyanine which is CI Pigment Blue 16, phthalocyanine whose central metal is Zn, Ni, Ti, etc., among which CI Pigment Blue 15: 3, 15: 4, aluminum phthalocyanine ) Is most preferred.

  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: 3, 48: 3, 48: 3). 4, 49: 1, 52: 1, 53: 1, 57: 1, 63: 2, 144, 146, 184), etc. 146, 184), quinacridone pigments (preferred examples include CI Pigment Red 122, 192, 202, 207, 209, CI Pigment Violet 19, 42, and among them, CI Pigment Red 122). Dye-attached lake pigment triarylcarbonium pigments (preferred examples include xanthene CI Pigment Red 81: 1, CI Pigment Violet 1, 2, 3, 27, 39), dioxazine pigments (for example, CI Pigment Violet 23, 37), diketopyrrolopyrrole pigment (eg CI Pigment Red 254), perylene pigment (eg CI Pigment Violet 29), anthraquinone Fee (e.g., C. I. Pigment Violet 5: 1, the 31, the 33), thioindigo (e.g. C. I. Pigment Red 38, the 88) is preferably used.

  As yellow pigments, 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, CI Pigment Yellow 93, 94, 95, 128, 155, benzimidazolone CI Pigment Yellow 120, 151, 154, 156, 180, etc. Among them, preferred are those using benzidine compounds as raw materials), isoindoline Isoindolinone pigments (preferred examples include CI Pigment Yellow 109, 110, 137, 139), quinophthalone pigments (preferred examples include CI Pigment Yellow 138), and furapantron pigments (for example, CI Pigment Yellow 24) 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 (CI Pigment Orange 13, 16, etc.) or a green pigment (CI Pigment Green 7, etc.) may be used.

The pigment that can be used in the ink of the present invention may be the aforementioned 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.
(i) Properties and applications of metal soap (Sachishobo)
(ii) Printing ink printing (CMC Publishing 1984)
(iii) Latest pigment application technology (CMC Publishing 1986)
(iv) U.S. Patent Nos. 5,554,739 and 5,571,311
(v) JP-A-9-151342, JP-A-10-140065, JP-A-10-292143, JP-A-11-166145 In particular, prepared by reacting carbon black with the diazonium salt described in the above-mentioned US patent (iv) Self-dispersing pigments and encapsulated pigments prepared by the method described in the Japanese patent (v) above are particularly effective because dispersion stability can be obtained without using an extra dispersant in the ink. It is.

In the 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 size of the pigment that can be used in the 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).

Next, the surfactant that can be contained in the inkjet ink of the present invention will be described.
By incorporating a surfactant into the ink-jet 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 the same effect.
Examples of the surfactant include anionic surfactants such as sodium dodecyl sulfate, sodium dodecyloxysulfonate, sodium alkylbenzenesulfonate, and cationic surfactants such as cetylpyridinium chloride, trimethylcetylammonium chloride, and terabutylammonium 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.

  The ink-jet ink of the present invention can be prepared by dissolving or dispersing the dye and preferably a surfactant in an aqueous medium. The “aqueous medium” in the present invention refers to a mixture of water or water and a small amount of a water-miscible organic solvent (the following water-soluble organic solvent), and additives such as stabilizers and preservatives are added as necessary. Means things.

When preparing the ink liquid of the present invention, in the case of water-soluble ink, it is preferable to first dissolve in water. 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.

The ink of the present invention preferably contains at least one organic solvent that is liquid at room temperature from the viewpoints of improving the permeability of the ink into the medium and preventing the precipitation of solid matter on the inkjet head. In particular, an organic solvent having a boiling point of 150 ° C. or higher and a water-soluble organic solvent excellent in miscibility with water is preferable. This water-soluble organic solvent may also function as an anti-drying agent, a penetration enhancer, a wetting agent, and the like for inkjet inks in this field.
Such water-soluble organic solvents include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyhydric alcohols (E.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), glycol derivatives (e.g., 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, diethylene) bird Min, triethylenetetramine, 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). These water-soluble organic solvents may be used in combination of two or more. These water-soluble organic solvents are preferably contained in the ink in a total amount of 5 to 75% by mass, more preferably 10 to 60% by mass, and particularly preferably 10 to 45% by mass.

  In the present invention, when forming an ink set having at least two or more cyan inks having different optical densities, in order to suppress the occurrence of bronze and improve the image quality, the ink set includes It is preferable to have a limiting condition.

1) The concentration of the water-soluble organic solvent contained in the ink is lower in the cyan ink (light cyan ink) having a lower optical density than in the cyan ink (normal cyan ink) having a higher optical density.
The content of the water-soluble organic solvent in the ink is preferably 10 to 65% by mass and more preferably 15 to 50% by mass in the light cyan ink. In normal cyan ink, it is preferably 15 to 75% by mass, and more preferably 20 to 60% by mass. The difference in concentration of the water-soluble organic solvent between the light cyan ink and the normal cyan ink is preferably 0.01 to 50% by mass, and more preferably 0.1 to 20% by mass.

2) Cyan ink (light cyan ink) having a low optical density when the solvent concentration of any one of glycol organic solvent, glycol alkyl ether organic solvent concentration and amide organic solvent contained in the ink is added Is lower than cyan ink (normal cyan ink) having higher optical density.
In the light cyan ink, the concentration of the added solvent in the ink is preferably 10 to 65% by mass, and more preferably 15 to 50% by mass. In normal cyan ink, it is preferably 15 to 75% by mass, and more preferably 20 to 60% by mass. The difference in the concentration of the added solvent between light cyan ink and normal cyan ink is preferably 0.01 to 50% by mass, and more preferably 0.1 to 20% by mass.

  These two conditions may be achieved independently, or two or all of them may be achieved. Preferably, the ink set that has been achieved is adopted.

The glycol organic solvent under the condition of the second term represents a solvent of a type in which ethylene glycol or propylene glycol is condensed, such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol or the like.
The glycol alkyl ether organic solvent represents an alkyl-substituted solvent with respect to the glycol solvent. Examples thereof include diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, triethylene glycol monopropyl ether and the like.
The amide organic solvent is an organic solvent having an amide bond in the molecule, and N, N-dimethylformamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methylpyrrolidone, N, N-dimethylimidazolidinone Etc.

When the dye is an oil-soluble dye, it can be prepared by dissolving the oil-soluble dye in a high-boiling 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, additives such as a surfactant, a wetting agent, a dye stabilizer, an emulsion stabilizer, an antiseptic and an antifungal agent, which will be described later, are added to either or both of the aqueous phase and the oil phase as necessary. be able to.
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 dye used in the present invention is water-soluble and the additive is oil-soluble.

When emulsifying and dispersing, various surfactants can be used. Anionic interfaces such as fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl sulfate esters, 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 —SO ₃ ⁻ 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 with various additives such as a wetting agent and a surfactant.
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.
As for the high-pressure homogenizer, detailed mechanisms are described in US Pat. No. 4,533,254, JP-A-6-47264, and the like. MICROFLUIDEX INC.), Optimizer (Sugino Machine Co., Ltd.) and the like.
In addition, a high-pressure homogenizer equipped with a mechanism for making fine particles in an ultrahigh-pressure jet stream as described in US Pat. 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. Also preferred is a method of once emulsifying and dispersing with these emulsifiers, adding an additive such as a wetting agent or a surfactant, and then passing the high-pressure homogenizer again while filling the cartridge with ink.
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 ink for inkjet recording of the present invention.

In the production of the ink-jet ink of the present invention, 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 ink-jet ink of the present invention, a step of removing dust that is a solid content by filtration, which is carried out after further preparation, 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.

  The ink-jet ink of the present invention includes a drying inhibitor for preventing clogging due to dry operation at the ink ejection port, a penetration accelerator for allowing the ink to penetrate better into the paper, an ultraviolet absorber, an antioxidant, An appropriate amount of additives such as a viscosity modifier, a surface tension modifier, a dispersant, a dispersion stabilizer, an antifungal agent, a rust inhibitor, a pH adjuster, an antifoaming agent, and a chelating agent can be appropriately selected and used.

  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 , Heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 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. 48-30492, 56-21114, and cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, and 8-239368. Triazine compounds and research discs described in JP-A-10-182621, JP-A-8-501291, etc. Ja 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, No. 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 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 other additive components.

The ink viscosity of the present invention is 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 30 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. For more details, see Chapter 9 of “Viscosity Preparation Technology” (Technical Information Association, 1999), and “Chemicals for Inkjet Printers (98 Supplement)-Material Development Trends and Perspective 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 mNm or less, more preferably 20 to 40 mNm or less at 25 ° C. for both dynamic and static surface tension. When the surface tension exceeds 50 mNm, the printing quality such as ejection stability, bleeding at the time of color mixing, whiskers, and the like is significantly deteriorated. Further, when the surface tension of the ink is set to 20 mNm or less, there may be a case where printing failure occurs due to adhesion of ink to the hard surface during ejection.
For the purpose of adjusting the surface tension, various surfactants of the cation, anion and nonionic types can be added. The surfactant is preferably used in the range of 0.01 to 20% by mass and more preferably in the range of 0.1 to 10% by mass with respect to the ink jet ink. 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 portion where the liquid surface and the plate are in contact. 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 ink of the present invention is 10 to 70% by mass of the total amount of the ink. Ink ejection stability, print image quality, various image robustness, image bleeding after printing, and stickiness of the printing surface In terms of reduction, it is preferably 20 to 60% by mass, and more preferably in terms of ink ejection stability and reduction of image blur 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 for ink-jet recording are dyes, high-boiling solvents, polymer latex added if necessary, surfactants, dye stabilizers, antifungal agents, buffering agents, etc. Other than the dye stabilizer, the dispersion stability of the ink is lowered, and since it remains on the inkjet image-receiving paper after printing, the stabilization due to the association of the dye on the image-receiving paper is inhibited, and various fastnesses and It has the property of exacerbating image bleeding under humidity 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 water-soluble polymer compounds 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, 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 which are 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.
In the present invention, nonionic, cationic or anionic surfactants may be mentioned as surface tension adjusting agents in addition to the surfactants described above. For example, anionic surfactants include fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl sulfates. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene Examples thereof include alkylamines, glycerin fatty acid esters, and oxyethyleneoxypropylene block copolymers. 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.

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

  Examples of the image receiving material used in the present invention include recording paper and recording film which are reflective media described below.

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 backcoat layer may be provided on the support as they are as the image-receiving material of the ink of the present invention, or after a size press or anchor coat layer is provided with starch, polyvinyl alcohol or the like, the image-receiving layer and the backcoat layer are provided. An image receiving material may be used. 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, and 11-348409. No. 2001-138621, 2000-43401, 2000-2111235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, Those disclosed in Nos. 8-2090, 8-2091, 8-2093, 8-174992, 11-192777, and JP-A-2001-301314 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.

  In the present invention, the volume of ink droplets onto the recording material is preferably from 0.1 pl to 100 pl. A more 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 that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element. ), An acoustic ink jet system that converts an electrical signal into an acoustic beam, irradiates the ink and ejects the ink using the radiation pressure, and a thermal ink jet (bubble jet) that heats the ink to form bubbles and uses the generated pressure (Registered trademark)) system.
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 the ink is ejected onto the recording material is preferably 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. For this reason, to increase the droplet ejection density for recording, the recording speed tends to be longer, but it is possible to increase the recording speed 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 using the inkjet ink of the present invention, for example, a mode as disclosed in JP-A-11-170527 is preferable. As the ink cartridge, one disclosed in, for example, Japanese Patent Laid-Open No. 5-229133 is preferable. With respect to the suction and the configuration of a cap or the like that covers the print head 28 at that time, for example, the one disclosed in Japanese Patent Application Laid-Open No. 7-276671 is suitable. Further, it is preferable that a filter for eliminating air 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 Japanese Patent Application 2001-16738. The application may be a printer connected to a computer or an apparatus specialized for printing photographs.

In the inkjet ink of the present invention, the average droplet ejection speed when ejecting onto a recording material is preferably 2 m / sec or more, and 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.

  The inkjet ink of the present invention can also be used for applications 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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this.

(Example 1)
After adding ultrapure water having a resistance value of 18 MΩ or more to the following components to make 1 liter, the mixture was stirred for 1 hour while being heated 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 the light cyan ink liquid LC-101.

[Light cyan ink liquid LC-101 prescription]
(Solid content)
C. I. Direct Blue 199 14g / l
Urea (UR) 15g / l
Benzotriazole (BTZ) 0.08g / l
PROXEL XL2 (PXL) 3.5g / l
(Liquid component)
Triethylene glycol (TEG) 110g / l
Glycerin (GR) 130g / l
Triethylene glycol monobutyl ether (TGB) 110g / l
2-pyrrolidone (PRD) 60g / l
Triethanolamine (TEA) 7g / l
Surfynol STG (SW) 10g / l

Furthermore, cyan ink (normal cyan ink) liquid C-101 having the following formulation was prepared.
[Normal cyan ink C-101 prescription]
(Solid content)
C. I. Direct Blue 199 45g / l
Urea (UR) 15g / l
Benzotriazole (BTZ) 0.08g / l
PROXEL XL2 (PXL) 3.5g / l
(Liquid component)
Triethylene glycol (TEG) 110g / l
Glycerin (GR) 130g / l
Triethylene glycol monobutyl ether (TGB) 110g / l
2-pyrrolidone (PRD) 60g / l
Triethanolamine (TEA) 7g / l
Surfynol STG (SW) 10g / l

  Next, as shown in Tables 1 and 2 below, inks were prepared in which the content of the dye used in the ink was changed. Here, the amount of dye used was adjusted so that the light absorbance of each of the light cyan ink and normal cyan ink was equal. The absorbance of the ink was measured using a thin layer liquid crystal cell having an optical path length of 5 μm.

  The λmax of each dye was in the range of 580 to 700 nm. The absorbance ratio I (λmax + 70 nm) / I (λmax) I. Direct Blue 199 was 0.775, Dye A was 0.682, Dye B was 0.675, and Dye C was 0.655.

  These inks are filled into an ink cartridge of an ink-jet printer = PM-980C manufactured by Seiko Epson Corporation, set in a black ink cartridge loading section, and a pattern of light cyan or normal cyan whose density changes stepwise in monochrome mode. A single color image was printed. As an image receiving sheet, an inkjet paper photo glossy paper EX manufactured by Fuji Photo Film Co., Ltd. was used, an image was printed on this, and the ozone fastness of the image was evaluated.

The forced fading rate constant for each ink was determined as follows.
The photo glossy paper on which the image has been formed is left in a box where the ozone gas concentration is set to 5 ppm, and the image density before and after being left under ozone gas is measured using a reflection densitometer (X-Rite 310TR). For the point of 0.0, the time until the reflection density decreased to 80% of the initial density (density 1.0) was evaluated. From this time, the forced fading rate constant defined in the present invention was determined.
The ozone gas concentration in the box was set using an ozone gas monitor (model: OZG-EM-01) manufactured by APPLICS.
The results are shown in Table 3.

The ink of the present invention has a forced fading rate constant of 5.0 × 10 ⁻² or less, and is excellent in weather resistance, particularly ozone durability.

(Example 2)
The following ink set was prepared using the ink of Example 1. Here, inks (LC-105, LC-106) using dye B were newly prepared according to the following formulation. In the following formulation, the concentration of Dye B is 20 g / l, which corresponds to the same concentration as LC-103.
Further, when the solubility of the cyan dye in water was measured, 30 g of dye A, 24 g of dye B, and 11 g of dye C were dissolved in 100 g of ultrapure water at 25 ° C.

[Light cyan ink LC-105 prescription]
(Solid content)
Dye B 20g / l
Urea (UR) 15g / l
Benzotriazole (BTZ) 0.08g / l
PROXEL XL2 (PXL) 3.5g / l
(Liquid component)
Triethylene glycol (TEG) 110g / l
Glycerin (GR) 130g / l
Triethylene glycol monobutyl ether (TGB) 140g / l
2-pyrrolidone (PRD) 80g / l
Triethanolamine (TEA) 7g / l
Surfynol STG (SW) 10g / l

[Light cyan ink LC-106 prescription]
(Solid content)
Dye B 20g / l
Urea (UR) 15g / l
Benzotriazole (BTZ) 0.08g / l
PROXEL XL2 (PXL) 3.5g / l
(Liquid component)
Triethylene glycol (TEG) 80g / l
Glycerin (GR) 130g / l
Triethylene glycol monobutyl ether (TGB) 80g / l
2-pyrrolidone (PRD) 10g / l
Triethanolamine (TEA) 7g / l
Surfynol STG (SW) 10g / l

Using these inks, ink sets shown in Table 4 were produced. The same forced fading speed constant as in Example 1 was obtained with light cyan ink LC-105, 106. The forced fading speed constant of the sample printed with LC-105 was 6.7 × 10 ⁻² [hour ⁻¹ ], The forced fading rate constant of the sample printed with LC-106 was 0.48 × 10 ⁻² [hour ⁻¹ ].

  These ink sets were filled in cyan & light cyan ink cartridges of an ink jet printer PM-980C manufactured by Seiko Epson Corporation, and set in each cartridge loading section to print an image. The other colors were prepared according to the following formulas, filled in the corresponding ink cartridges, and set in the filling section. In addition, in the following prescription, all prepared using ultrapure water so that it might become a finished quantity of 1 liter.

[Light magenta ink prescription]
(Solid content)
Magenta dye (M-1) 7.5g / l
Urea (UR) 10g / l
PROXEL XL2 (PXL) 5g / l
(Liquid component)
Diethylene glycol (DEG) 90g / l
Glycerin (GR) 70g / l
Triethylene glycol monobutyl ether (TGB) 70g / l
Triethanolamine (TEA) 6.9 g / l
Surfynol STG (SW) 10g / l

[Magenta ink prescription]
(Solid content)
Magenta dye (M-1) 23g / l
Urea (UR) 15g / l
PROXEL XL2 (PXL) 5g / l
(Liquid component)
Diethylene glycol 90g / l
Glycerin 70g / l
Triethylene glycol monobutyl ether (TGB) 70g / l
Triethanolamine 6.9g / l
Surfynol STG 10g / l

[Yellow ink prescription]
(Solid content)
Yellow dye (Y-1) 35g / l
PROXEL XL2 (PXL) 3.5g / l
Benzotriazole (BTZ) 0.08g / l
Urea 10g / l
(Liquid component)
Triethylene glycol monobutyl ether (TGB) 130g / l
Glycerin (GR) 115g / l
Diethylene glycol (DEG) 120g / l
2-pyrrolidone (PDR) 35g / l
Triethanolamine (TEA) 8g / l
Surfynol STG (SW) 10g / l

[Dark yellow ink prescription]
(Solid content)
Yellow dye (Y-1) 35g / l
Magenta dye (M-1) 2g / l
Cyan dye (B) 2g / l
Proxel 5g / l
Benzotriazole (BTZ) 0.08g / l
Urea 10g / l
(Liquid component)
Triethylene glycol monobutyl ether (TGB) 140g / l
Glycerin (GR) 125g / l
Diethylene glycol (DEG) 120g / l
2-pyrrolidone (PDR) 35g / l
Triethanolamine (TEA) 8g / l
Surfynol STG (SW) 10g / l

[Black ink prescription]
(Solid content)
Black dye (Bk-1) 75g / l
Black dye (Bk-2) 30g / l
PROXEL XL2 (PXL) 5g / l
Urea 10g / l
Benzotriazole 3g / l
(Liquid component)
Diethylene glycol monobutyl ether (DGB) 120g / l
Glycerin (GR) 125g / l
Diethylene glycol (DEG) 100g / l
2-pyrrolidone (PDR) 35g / l
Triethanolamine (TEA) 8g / l
Surfynol STG (SW) 10g / l

  As the image receiving sheet, Fuji Photo Film Co., Ltd. Inkjet Paper Photo Glossy Paper EX was used. Images were printed on this, and the images were evaluated and the ozone fastness was evaluated. The results are shown in Table 5.

<Evaluation of image>
A: A uniform and uniform image is obtained.
B: Bronze or beading is allowed.
C: Both bronze and beading are allowed.

<Evaluation of ozone fastness>
When storing the image for 3 days under the condition of ozone concentration 5ppm,
X: Image deterioration is greatly recognized.
○: Image degradation is at an acceptable level.

As shown in Table 5, when an ink having a forced fading rate constant of 5 × 10 ⁻² [hour ⁻¹ ] or more is used for light cyan ink and normal cyan ink (IS-201), ozone resistance is reduced. poor. Also, in the case of an ink set in which the light cyan ink has a forced fading rate constant larger than that of the normal cyan ink (IS-202), or the water-soluble organic solvent concentration or the additive solvent concentration defined in the present invention is light cyan ink than the normal cyan ink. In the case of the ink set in which is higher (IS-203), bronze and beading were recognized in the printed image.
On the other hand, the light cyan ink has a forced fading rate constant smaller than that of normal cyan ink, and the water-soluble organic solvent concentration and the additive solvent concentration defined in the present invention are lower in the light cyan ink (IS-204, In IS-205 and IS-206), good results were obtained in both image quality and ozone resistance. From this result, the effect of the present invention is clear.

Claims (7)

At least one dye having an absorbance ratio I (λmax + 70 nm) / I (λmax) of λmax of 580 nm to 700 nm and an absorbance I (λmax) of λmax and an absorbance I (λmax + 70 nm) of λmax + 70 nm of 0.75 or less, aqueous An inkjet cyan ink dissolved or dispersed in a medium, and after the ink is printed on a reflective medium, the reflection density (D _R ) in a cyan region measured through a status A filter is 0.90 to 1. 10 points are defined as the initial density of the ink, and the print is forcibly faded using an ozone fading tester capable of always generating 5 ppm of ozone, and the reflection density is 80% of the initial density. An ink-jet cyan ink, wherein the forced fading rate constant determined from the time until it becomes% is 5.0 × 10 ⁻² [hour ⁻¹ ] or less.   2. The cyan ink for ink jet according to claim 1, wherein the absorbance ratio I (λmax + 70 nm) / I (λmax) is 0.70 or less.   3. The cyan ink for inkjet according to claim 1, wherein the oxidation potential of the dye is nobler than 1.0 V (vs SCE). 4. The ink-jet cyan ink according to claim 1, wherein the dye is a compound represented by the following general formula (1).
General formula (1)

In the general formula (1), X ₂₁ , X ₂₂ , X ₂₃ and X ₂₄ are each independently —SO—Z ₂ , —SO ₂ —Z ₂ , —SO ₂ NR ₂₁ R ₂₂ , a sulfo group, —CONR. ₂₁ R ₂₂ or —COOR ₂₁ is represented. Z ₂ each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or Represents a substituted or unsubstituted heterocyclic group. R ₂₁ and R ₂₂ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, substituted or unsubstituted It represents a substituted aryl group or a substituted or unsubstituted heterocyclic group.
Y ₂₁ , Y ₂₂ , Y ₂₃ and Y ₂₄ each independently represent a monovalent substituent.
_{a 21 ~a 24, b 21 ~b} 24 each represent the number of substituents of X ₂₁ to X ₂₄ and Y ₂₁ to Y _24. a _{21 to} a ₂₄ each independently represents a number of 0 to 4, but they are not all 0 at the same time. b ₂₁ ~b ₂₄ represents the number of independently 0-4. Incidentally, when a ₂₁ ~a ₂₄ and b ₂₁ ~b ₂₄ represents the number of 2 or more, plural X ₂₁ to X ₂₄ and Y ₂₁ to Y ₂₄ may be the same as or different from each other to each other.
M is a hydrogen atom, a metal atom or an oxide, hydroxide or halide thereof.   The cyan ink according to any one of claims 1 to 4, wherein the ink set is an ink jet ink set including at least two or more cyan inks having different optical densities, wherein the forced fading speed constant according to claim 1 has an optical density of An ink set for ink jet, wherein a low cyan ink is smaller than a cyan ink having a high optical density.   The cyan ink according to any one of claims 1 to 4, wherein the ink set is an inkjet ink set including at least two or more cyan inks having different optical densities, and the water-soluble organic solvent concentration contained in the ink is low. An ink-jet ink set, wherein cyan ink has a lower optical density than cyan ink.   The cyan ink according to any one of claims 1 to 4, wherein the ink set for inkjet includes at least two kinds of cyan inks having different optical densities, wherein the glycol organic solvent and glycol alkyl ether organic solvent are contained in the ink. An ink-jet ink set, wherein a cyan ink having a lower optical density has a lower solvent density than a cyan ink having a higher optical density when the concentration of any two of the density and the amide organic solvent is added.