JP2008094898A - Ink, ink set, method of inkjet-recording and ink cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ink excellent in color development satisfying a high color development property to the recently desired extent and effective for reproducing a monitor image such as blue sky, an in-water image, etc. <P>SOLUTION: This ink containing a copper phthalocyanine dyestuff is provided by containing at least 1 kind of xanthene dyestuff expressed by general formula (1). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink excellent in color reproducibility and light resistance suitable as an ink for ink jet recording, and an ink set, an ink jet recording method, and an ink cartridge using the ink.

  Conventionally, water-based color inks in which dyes having respective color tones are dissolved in a water-soluble medium are used for color recording using an ink jet recording method. For those color inks, an optimum one is selected from among a number of color materials, and the color tone is adjusted. Generally, three colors of cyan, magenta, and yellow are used as color inks used for color recording. In recent years, in order to faithfully reproduce an RGB image, an ink jet printing method using special colors such as red, green and blue inks having excellent color developability in addition to the above three primary colors has been proposed and implemented. Among the special colors, the blue ink is effective for reproducing a monitor image such as a blue sky or an underwater image, and is increasingly used.

  The blue ink used at this time may be composed of a single color material (see Patent Documents 1 and 2). However, no blue ink having such excellent color developability that can sufficiently realize the color developability required in recent years has not been developed yet. For this reason, the blue ink is often composed of two kinds of color materials, cyan and magenta, or a larger number of color materials (see, for example, Patent Documents 3 to 5). For example, in Patent Document 5, there is a blue ink containing a cyan color material contained in a cyan ink used for color recording and a magenta color material having a xanthene structure not contained in a magenta ink used together. It is disclosed.

  However, even when two types of inks, cyan and magenta, which have been conventionally used as inkjet inks, are combined, they are still insufficient for the color development of blue images that have been required in recent years. On the other hand, with the recent expansion of the use of ink jet recording methods, the demand for image fastness has further increased, and blue inks having excellent fastness such as light resistance have been demanded.

JP-A-9-111673 JP 2004-250606 A JP 2001-220529 A JP 2002-220555 A JP 2000-273374 A

  As described above, since it is effective for reproducing a monitor image such as a blue sky or an underwater image, the blue ink is particularly required to have excellent color developability. However, the blue ink used as the special color ink will not show the effect on the actual image unless it has a color developability superior to that of the blue color obtained by overlapping printing of cyan ink and magenta ink used together. Therefore, there is a strong demand for the development of blue inks with better color developability.

  On the other hand, with respect to image fastness, there is a strong demand for improvement particularly against light degradation. This is because xanthene dyes with good color developability that have been resistant to degradation by environmental gases have been reported so far, but those that are resistant to light degradation have not yet been known. That is, when an image is formed using a conventional xanthene dye as a magenta dye for blue ink, the fading due to the light of the xanthene dye appears remarkably.

  Patent Document 5 described above discloses a blue ink for the purpose of improving light resistance. However, it does not disclose a blue ink having a color development as high as desired in recent years, including those disclosed in Examples.

  Accordingly, a first object of the present invention is to provide an aqueous blue ink excellent in color developability, which is effective for reproducing a monitor image such as a blue sky or an underwater image, which can satisfy a high color developability as required in recent years. That is. The second object of the present invention is to provide a water-based blue ink having excellent light resistance in addition to the above-mentioned problems. Furthermore, a third object of the present invention is to provide an ink jet recording method capable of giving an image excellent in color developability and fastness using these inks.

  In order to achieve the above object, the present inventors have studied blue ink. First, a search was made for a dye that would be a good blue ink with a single colorant, but none found a problem. Next, many studies were made on blue inks combining two coloring materials. Surprisingly, by combining a specific xanthene dye and a copper phthalocyanine dye, it is possible to express a color gamut that cannot be expressed when each dye is used alone (a synergistic effect in color development). ) Was found. Furthermore, as a result of intensive studies, it has been found that a synergistic effect on color developability is more remarkable by combining a specific xanthene dye and a specific copper phthalocyanine dye.

（式（１）中、Ｚ₁乃至Ｚ₄はそれぞれ独立に、水素原子、ハロゲン原子、ヒドロキシル基、アルキル基、アルコキシ基、トリフルオロメチル基、カルボキシル基、スルホン酸基、置換していてもよいアミド基から選択される何れかを表す。Ｍは、水素原子、アルカリ金属イオン、アンモニウムイオンから選択される何れかを表す。） Specifically, as described below, the above-described problems are achieved by the present invention described below. That is, the present invention is an ink containing at least one xanthene dye represented by the following general formula (1) in an ink containing a copper phthalocyanine dye.

(In the formula (1), Z _{1 to} Z ₄ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkoxy group, a trifluoromethyl group, a carboxyl group, a sulfonic acid group, or may be substituted. Represents any one selected from amide groups, M represents any one selected from a hydrogen atom, an alkali metal ion, and an ammonium ion.)

  Further, as a more preferable form of the present invention, there are xanthene dyes represented by the general formula (1), which have a specific structure. However, according to such form, color development and fastness can be achieved at a higher level. Sexual compatibility is possible.

（式（２）中、Ｚ₅及びＺ₆はカルボキシル基を表し、又、Ｚ₇及びＺ₈はそれぞれ独立に、水素原子、ハロゲン原子、ヒドロキシル基、アルキル基、アルコキシ基、トリフルオロメチル基、カルボキシル基、スルホン酸基及び置換していてもよいアミド基から選択される何れかを表す。又、Ｍは、水素原子、アルカリ金属イオン、アンモニウムイオンから選択される何れかを表す。）
又、本発明のより好ましい形態としては、キサンテン染料の含有量（Ａ）と銅フタロシアニン染料の含有量（Ｂ）比（Ａ：Ｂ）が０．２：１乃至４：１である上記何れかのインクである。 Specifically, among the xanthene dyes represented by the general formula (1), the ink is a xanthene dye represented by the following general formula (2).

(In the formula (2), Z ₅ and Z ₆ represents a carboxyl group, and each Z ₇ and Z ₈ independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkoxy group, a trifluoromethyl group, This represents any one selected from a carboxyl group, a sulfonic acid group, and an optionally substituted amide group, and M represents any one selected from a hydrogen atom, an alkali metal ion, and an ammonium ion.)
Further, as a more preferable embodiment of the present invention, any one of the above, wherein the ratio (A) of xanthene dye (A) and copper phthalocyanine dye (B) (A: B) is 0.2: 1 to 4: 1. Ink.

Moreover, the following are mentioned as another embodiment of this invention. An ink set comprising at least a combination of any ink selected from cyan, magenta, and yellow and blue ink used for inkjet recording, wherein the blue ink is any one of the inks described above An ink set;
In an inkjet recording method for recording on a recording medium by discharging ink from an orifice in accordance with a recording signal, the ink is any one of the above-described inks;
An ink cartridge including an ink storage portion that stores ink, wherein the ink is any one of the inks described above.

  According to the ink set, the ink jet recording method, and the ink cartridge of the present invention having the above-described configuration, when an image is formed on a recording medium by using the ink of the present invention, a recorded image having excellent color developability can be obtained. Obtainable. Furthermore, according to the ink set, ink jet recording method, and ink cartridge of the present invention, a recorded image having excellent light resistance can be obtained.

  According to one embodiment of the present invention, there is provided a blue ink that has excellent color developability and color reproducibility as an inkjet ink and is excellent in fastness such as light resistance. In addition, an ink set, an ink cartridge, and an ink jet recording method using the blue ink are provided.

  The best mode for carrying out the present invention will be described below. In the present invention, when the dye is a salt, it is dissociated into ions in the ink but is expressed as “contains a salt” for convenience.

《Blue ink》
The blue ink of the present invention is characterized by containing at least one copper phthalocyanine dye and a xanthene dye represented by the following general formula (1). For example, when an ink for inkjet recording is used, these color materials are dissolved or dispersed in water and a water-soluble organic solvent to obtain an aqueous ink.

[Color material]
<Xanthene dye>
The performance required for the xanthene dye used in the present invention is such that when the ink is mixed with a copper phthalocyanine dye, a synergistic effect is observed, and further, excellent light resistance and color developability are exhibited. As a result of investigations by the present inventors, the above characteristics are achieved by using a xanthene dye represented by the following general formula (1). As shown in the general formula (1), by having a hydrogen bonding substituent such as a carboxyl group at the O position with respect to the amino group, the shape of the xanthene molecular structure is stabilized and it is difficult to take a planar structure. Therefore, the association of xanthene dyes is inhibited, as well as the association of copper phthalocyanine dyes. As a result, the dye molecules can be dispersed and exist, and it is presumed that the color developability is further improved.

(In the formula (1), Z _{1 to} Z ₄ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkoxy group, a trifluoromethyl group, a carboxyl group, a sulfonic acid group, or may be substituted. Represents any one selected from amide groups, M represents any one selected from a hydrogen atom, an alkali metal ion, and an ammonium ion.)

  Regarding the colorant represented by the general formula (1), according to further studies, a xanthene compound represented by the following general formula (2) is particularly preferably used. It is also possible to use a mixture of two or more of these. In general, it is considered that the degradation of the xanthene dye proceeds when the amino group portion is cleaved. As shown in the general formula (2), this xanthene compound has a hydrogen bonding substituent which is a carboxyl group at the 2nd and 6th positions, and the amino group is protected by hydrogen bonds from both sides. For this reason, it is estimated that it will become difficult to deteriorate and light resistance will improve significantly.

（式（２）中、Ｚ₅及びＺ₆はカルボキシル基を表し、又、Ｚ₇及びＺ₈はそれぞれ独立に、水素原子、ハロゲン原子、ヒドロキシル基、アルキル基、アルコキシ基、トリフルオロメチル基、カルボキシル基、スルホン酸基及び置換していてもよいアミド基から選択される何れかを表す。又、Ｍは、水素原子、アルカリ金属イオン、アンモニウムイオンから選択される何れかを表す。）

(In the formula (2), Z ₅ and Z ₆ represents a carboxyl group, and each Z ₇ and Z ₈ independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkoxy group, a trifluoromethyl group, This represents any one selected from a carboxyl group, a sulfonic acid group, and an optionally substituted amide group, and M represents any one selected from a hydrogen atom, an alkali metal ion, and an ammonium ion.)

  Specific examples of the xanthene dye represented by the above general formula (1) or (2) are shown below, but the xanthene compound used in the present invention is not limited to the following examples. In addition, the following exemplary compound was described in the form of the free acid.

  Among the above-described compounds, Exemplified Compound 1 and Exemplified Compound 2 are preferable from the balance between the color developability and light resistance, and Exemplified Compound 2 is the most preferable compound.

<Phthalocyanine dye>
Examples of the copper phthalocyanine dye used in the present invention include C.I. I. Any of existing compounds such as Direct Blue 199 can be used, but particularly preferred are compounds represented by the following general formulas (3) and (4). This is because these compounds are particularly excellent in fastness and color development and have a great effect when mixed with xanthene dyes. Regarding the use of these coloring materials, it is also possible to select one from a phthalocyanine compound represented by the general formulas (3) and (4), or to use a mixture of two or more.

（上記一般式（３）中、ｌ＝０乃至２、ｍ＝１乃至３、ｎ＝１乃至３、但し、ｌ＋ｍ＋ｎ＝３乃至４、置換基の置換位置は、４若しくは４’位を表し、Ｍはアルカリ金属又はアンモニウムであり、Ｒ₁、Ｒ₂は、それぞれ独立に、水素原子、スルホ基、カルボキシル基（但し、Ｒ₁、Ｒ₂は、同時に水素原子となる場合を除く。）を表し、Ｙは、塩素原子、ヒドロキシル基、アミノ基、置換基を有してもよいモノ又はジアルキルアミノ基を表す。） (A) Compound represented by general formula (3)

(In the general formula (3), l = 0 to 2, m = 1 to 3, n = 1 to 3, provided that l + m + n = 3 to 4, and the substitution position of the substituent represents the 4 or 4 ′ position, M is an alkali metal or ammonium, and R ₁ and R ₂ each independently represents a hydrogen atom, a sulfo group, or a carboxyl group (except that R ₁ and R ₂ are simultaneously hydrogen atoms). Y represents a chlorine atom, a hydroxyl group, an amino group, or a mono- or dialkylamino group which may have a substituent.

The compound represented by the general formula (3) is a 4-sulfophthalic acid derivative, or a phthalocyanine compound obtained by reacting a 4-sulfophthalic acid derivative with an (anhydrous) phthalic acid derivative in the presence of a metal compound. And can be synthesized as follows. That is, after the sulfo group in the raw material is converted into a chlorosulfone group, it is limited to the phthalocyanine compound in which an aminating agent is reacted in the presence of an organic amine, that is, the 4 and 4 ′ positions in the general formula (3). It is characterized by being a phthalocyanine compound into which an unsubstituted sulfamoyl group (—SO ₂ NH ₂ ) and a substituted sulfamoyl group (the following formula (5)) are introduced, and an ink using such a compound as a coloring material has extremely high environmental gas resistance I found that it is excellent.

  Specific examples of the substituted sulfamoyl group represented by the above formula (5) are shown below, but the phthalocyanine dye used in the present invention is not limited to the following examples. The above formula (5) is shown in the form of free acid.

  Among these, the compound of the general formula (3) having the exemplified compound 11 as a substituent is the most preferable compound because of its balance between color development and environmental gas resistance.

（上記一般式（４）中、Ｍはスルホン酸基の対イオンであり、水素原子、アルカリ金属、アンモニウム或いは有機アンモニウムの何れかを表す。） (B) Compound represented by general formula (4)

(In the general formula (4), M is a counter ion of a sulfonic acid group, and represents any one of a hydrogen atom, an alkali metal, ammonium, or organic ammonium.)

  Specific examples of the compound represented by the formula (4) are shown below, but the phthalocyanine dye used in the present invention is not limited to the following examples.

<Use ratio of xanthene dye and phthalocyanine dye>
The content ratio of the xanthene dye (A) and the copper phthalocyanine dye (B) in the ink is A: B = 0.2: 1 to 4: 1 (A / B = 0.2) from the viewpoint of color development. To 4.0) is effective. When the content ratio of the xanthene dye is smaller than this (A / B is less than 0.2), the ratio of the xanthene dye in the color material is too small and it is difficult to obtain a synergistic effect due to mixing. On the other hand, even when the content ratio of xanthene dye is larger than this (A / B is larger than 4.0), the ratio of the copper phthalocyanine dye in the color material is too small, and a synergistic effect of color development is obtained. Hateful.

<Other colorants>
Further, the ink of the present invention may further contain another color material for the purpose of color matching. Examples thereof are listed below, but are not limited thereto.
(Yellow color material)
C. I. Direct yellow: 8, 11, 12, 27, 28, 33, 39, 44, 50, 58, 85, 86, 87, 88, 89, 98, 100, 110, 132, 173, etc. I. Acid Yellow: 1, 3, 7, 11, 17, 23, 25, 29, 36, 38, 40, 42, 44, 76, 98, 99 etc. C.I. I. Pigment Yellow: 1, 2, 3, 12, 13, 14, 15, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 114, 128, 138, 180, etc.

(Magenta color material)
C. I. Direct Red: 2, 4, 9, 11, 20, 23, 24, 31, 39, 46, 62, 75, 79, 80, 83, 89, 95, 197, 201, 218, 220, 224, 225, 226 227, 228, 229, 230 etc. C.I. I. Acid Red: 6, 8, 9, 13, 14, 18, 26, 27, 32, 35, 42, 51, 52, 80, 83, 87, 89, 92, 106, 114, 115, 133, 134, 145 158, 198, 249, 265, 289, etc. C.I. I. Food Red: 87, 92, 94, etc. I. Direct violet: 107 grade C.I. I. Pigment Red: 2, 5, 7, 12, 48: 2, 48: 4, 57: 1, 112, 122, 123, 168, 184, 202, etc.

(Cyan color material)
C. I. Direct Blue: 1, 15, 22, 25, 41, 76, 80, 90, 98, 106, 108, 120, 158, 163, 168, 226 etc. C.I. I. Acid Blue: 1, 7, 15, 22, 23, 25, 29, 40, 43, 59, 62, 74, 78, 80, 90, 100, 102, 104, 117, 127, 138, 158, 161, 203 204, 244 etc. C.I. I. Pigment Blue: 1, 2, 3, 15, 15: 2, 15: 3, 15: 4, 16, 22, 60, etc.

(Orange color material)
C. I. Acid Orange: 7, 8, 10, 12, 24, 33, 56, 67, 74, 88, 94, 116, 142, etc. C.I. I. Acid Red: 111, 114, 266, 374, etc. C.I. I. Direct orange: 26, 29, 34, 39, 57, 102, 118 etc. C.I. I. Food Orange: 3 etc. C.I. I. Reactive orange: 1, 4, 5, 7, 12, 13, 14, 15, 16, 20, 29, 30, 84, 107, etc. I. Disperse orange: 1, 3, 11, 13, 20, 25, 29, 30, 31, 32, 47, 55, 56 etc. C.I. I. Pigment orange: 43 mag C.I. I. Pigment Red: 122, 170, 177, 194, 209, 224, etc.

(Green color material)
C. I. Acid Green: 1, 3, 5, 6, 9, 12, 15, 16, 19, 21, 25, 28, 81, 84 etc. C.I. I. Direct green: 26, 59, 67 etc. I. Food Green: 3rd grade C.I. I. Reactive Green: 5, 6, 12, 19, 21 etc. C.I. I. Disperse Green: 6, 9 etc. C.I. I. Pigment Green: 7, 36 etc.

(Blue color material)
C. I. Acid Blue: 62, 80, 83, 90, 104, 112, 113, 142, 203, 204, 221, 244, etc. C.I. I. Reactive Blue: 49 etc. C.I. I. Acid Violet: 17, 19, 48, 49, 54, 129, etc. C.I. I. Direct violet: 9, 35, 47, 51, 66, 93, 95, 99 etc. C.I. I. Reactive violet: 1, 2, 4, 5, 6, 8, 9, 22, 34, 36 etc. C.I. I. Disperse violet: 1, 4, 8, 23, 26, 28, 31, 33, 35, 38, 48, 56 etc. C.I. I. Pigment Blue: 15: 6 etc. C.I. I. Pigment Violet: 19, 23, 37, etc.

(Black color material)
C. I. Direct black: 17, 19, 22, 31, 32, 51, 62, 71, 74, 112, 113, 154, 168, 195, etc. I. Acid Black: 2, 48, 51, 52, 110, 115, 156 etc. C.I. I. Food black: 1st, 2nd grade carbon black, etc.

[Water-soluble organic solvents and additives]
In addition, the ink of the present invention is characterized by containing the specific xanthene dye and the copper phthalocyanine compound described above. For example, when an ink for inkjet is used, these coloring materials are used in an aqueous medium. Is dissolved or dispersed. As the aqueous medium, it is preferable to use a mixed medium of water and a water-soluble organic solvent. The following are mentioned as a preferable water-soluble organic solvent. For example, C1-C4 alkanols such as ethanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol and the like;
Carboxylic acid amides such as N, N-dimethylformamide or N, N-dimethylacetamide;
Ketones such as acetone, methyl ethyl ketone, 2-methyl-2-hydroxypentan-4-one, or cyclic ethers such as ketoalcohol, tetrahydrofuran, dioxane;
Glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2- or 1,3-propylene glycol, 1,2- or 1,4-butylene glycol, polyethylene glycol;
1,3-butanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol;
Polyhydric alcohols such as dithioglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivatives, trimethylolpropane;
Alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monoethyl (or butyl) ether;
2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, heterocycles such as N-methylmorpholine, sulfur-containing compounds such as dimethyl sulfoxide, urea, urea derivatives, etc. A suitable example is given.

〔Additive〕
In addition to the above, the ink of the present invention includes a surfactant, a pH adjuster, a chelating agent, a rust inhibitor, an antiseptic, an antifungal agent, an ultraviolet absorber, a viscosity adjuster, and an antifoam as necessary. Various additives such as an agent and a water-soluble polymer may be contained.

(Surfactant)
As the surfactant, for example, an anionic surfactant, an amphoteric surfactant, a cationic surfactant, a nonionic surfactant and the like can be used. Specific examples of the surfactant that can be used include the following.

Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, and N-acyl methyl taurate salts;
Alkyl sulfate polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap;
Castor oil sulfate ester salt, lauryl alcohol sulfate ester salt, alkylphenol type phosphate ester, alkyl type phosphate ester, alkylallyl sulfone hydrochloride, diethyl sulfosuccinate, diethylhexyl sulfosuccinate dioctyl sulfosuccinate and the like.

  Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

  Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, and other imidazoline derivatives. Etc.

Nonionic surfactants include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether,
Ethers such as polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyallylalkyl alkyl ether;
Polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate,
Ester systems such as sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate;
2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol An acetylene glycol system such as
Examples of commercially available acetylene glycol-based nonionic surfactants include acetylenol EH manufactured by Kawaken Fine Chemical Co., Ltd., Surfynol 104, 82, 465 manufactured by Nisshin Chemical Co., Ltd., and Olfin STG.

(PH adjuster)
As the pH adjusting agent, any substance can be used as long as it can control the pH of the ink within a predetermined range. For example, alcohol amine compounds such as diethanolamine, triethanolamine, isopropanolamine, trishydroxymethylaminomethane;
Examples include alkali metal hydroxides such as lithium hydroxide and potassium hydroxide, ammonium hydroxide, and alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate.

(Antiseptic, antifungal agent)
Examples of antiseptic and mildewproofing agents include organic sulfur, organic nitrogen sulfur, organic halogen, haloallylsulfone, iodopropargyl, N-haloalkylthio, benzthiazole, nitrityl, pyridine, 8 -Oxyquinoline,
Benzothiazole, isothiazoline, dithiol, pyridine oxide, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiadiazine, anilide, adamantane,
Examples include dithiocarbamate, brominated indanone, benzyl bromacetate, and inorganic salt compounds.

Examples of the organic halogen compound include sodium pentachlorophenol, and examples of the pyridine oxide compound include 2-pyridinethiol-1-oxide sodium. An example of the inorganic salt compound is anhydrous sodium acetate. Examples of the isothiazoline-based compound include 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one,
Examples include 5-chloro-2-methyl-4-isothiazolin-3-one magnesium chloride and 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride. Other antiseptic / antifungal agents include sodium sorbate sodium benzoate and the like, for example, Avecia Proxel GXL (S), Proxel XL-2 (S) and the like.

(Chelating agent)
Examples of the chelating agent include sodium citrate, sodium ethylenediaminetetraacetate, sodium dinitrotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate and the like.

(anti-rust)
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

(UV absorber)
Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, cinnamic acid compounds, triazine compounds, and stilbene compounds;
Alternatively, a compound that absorbs ultraviolet rays typified by a benzoxazole-based compound and emits fluorescence, a so-called fluorescent brightener can also be used.

(Viscosity modifier / antifoaming agent)
Examples of the viscosity modifier include water-soluble polymer compounds in addition to water-soluble organic solvents, such as polyvinyl alcohol, cellulose derivatives, polyamines, and polyimines. As the antifoaming agent, a fluorine-based or silicone-based compound is used as necessary.

"ink cartridge"
The ink cartridge of the present invention contains the ink of the present invention described above in an ink container. Accordingly, the ink cartridge may have any structure as long as it has an ink storage portion that stores the ink of the present invention. Specific examples of ink cartridges suitable for recording using the ink of the present invention are shown below.

  FIG. 1 is a schematic explanatory view and a cross-sectional view of a liquid storage container which is an ink cartridge suitable for performing recording using the ink of the present invention. In FIG. 1, the liquid storage container (ink tank) is connected to the atmosphere via the atmosphere communication port 112 in the upper part, communicates with the ink supply port in the lower part, and stores a negative pressure generation member storage chamber 134 in which the negative pressure generation member is accommodated. And a substantially sealed liquid storage chamber 136 for storing liquid ink by a partition wall 138. The negative pressure generating member storage chamber 134 and the liquid storage chamber 136 are connected to the communication hole 140 formed in the partition wall 138 near the bottom of the liquid storage container (ink tank) and the introduction of the atmosphere into the liquid storage chamber during the liquid supply operation. It communicates only through an air introduction groove (atmosphere introduction path) 150 for promoting the above. A plurality of ribs are integrally formed on the upper wall of the liquid container (ink tank) that defines the negative pressure generating member storage chamber 134 so as to protrude into the inside, and is compressed into the negative pressure generating member storage chamber 134. Is in contact with the negative pressure generating member accommodated in. By this rib, an air buffer chamber is formed between the upper wall and the upper surface of the negative pressure generating member. Further, the ink supply cylinder provided with the liquid supply port 114 is provided with a pressure contact body 146 having a higher capillary force and a higher physical strength than the negative pressure generating member, and is in pressure contact with the negative pressure generating member.

  In the illustrated negative pressure generating member storage chamber, as the negative pressure generating member, two capillary force generations of a first negative pressure generating member 132B and a second negative pressure generating member 132A made of olefin resin fibers such as polyethylene are generated. The mold negative pressure generating member is accommodated. Reference numeral 132C denotes a boundary layer between the two negative pressure generating members, and an intersecting portion of the boundary layer 132C with the partition wall 138 has an air introduction groove (atmosphere introduction path) in a posture when the liquid storage container is used with the communication portion downward. ) It exists above the upper end of 150. Further, the ink accommodated in the negative pressure generating member exists above the boundary layer 132C as indicated by the ink level L.

  Here, the boundary layer between the first negative pressure generating member and the second negative pressure generating member is in pressure contact, and the vicinity of the boundary layer of the negative pressure generating member has a higher compressibility than other parts, and the capillary force Is in a strong state. That is, assuming that the capillary force of the first negative pressure generating member is P1, the capillary force of the second negative pressure generating member is P2, and the capillary force of the interface between the negative pressure generating members is PS, P2 <P1 <PS. It has become.

  FIG. 2 is a schematic explanatory view and a cross-sectional view of a liquid storage container which is still another ink cartridge suitable for recording using the ink of the present invention. The illustrated ink cartridge includes a container 41 that stores ink of three colors, yellow (Y), magenta (M), and cyan (C), and a lid member 42 that covers the container 41. The interior of the container 41 is partitioned into three spaces having substantially the same capacity by two partition plates 411 and 412 arranged in parallel to each other in order to accommodate three colors of ink. These three spaces are aligned along the insertion direction of the color ink tank when the color ink tank is attached to the ink tank holder. In each of these spaces, an ink absorber 44Y that absorbs and holds yellow ink, an ink absorber 44M that absorbs and holds magenta ink, and an ink absorber 44C that absorbs and holds cyan ink. Is stored. Further, the ink accommodated in the ink absorber 44Y, the ink absorber 44M, and the ink absorber 44C, which are negative pressure generating members, reaches the top of each ink absorber as indicated by the ink level L. Existing.

<Inkjet recording method>
The inkjet recording method of the present invention is characterized in that recording is performed on a recording medium by ejecting the ink of the present invention from an orifice in accordance with a recording signal. In particular, the ink of the present invention can be preferably used in an ink jet recording method for recording on a recording medium by applying thermal energy to the ink.

  EXAMPLES Hereinafter, although an Example is given and this description is demonstrated further more concretely, this invention is not limited to a following example. In the text, “parts” and “%” are based on mass unless otherwise specified.

[Examples 1-6 and Comparative Examples 1-3]
(Preparation of ink)
Inks were prepared according to the formulations shown in Table 1 below, and each was pressure filtered through a 0.2 μm membrane filter, and then inks of Examples 1 to 6 and Comparative Examples 1 to 3 shown in Table 1 below were obtained. . Unless otherwise specified, the ink components in Examples and Comparative Examples mean mass%. In addition, as the comparative compound 1, a compound having the following structure was used.

(Evaluation of ink)
Using each ink prepared above, printing was performed using the following apparatus, and the ink was evaluated as described later. Printing was performed using a thermal ink jet printer (trade name: PIXUS iP8600; manufactured by Canon) that discharges ink droplets using thermal energy. At this time, each ink was filled in the ink tank of the ink cartridge having the structure shown in FIG. 1, and printing was performed using this ink tank. Then, various tests described below were performed.

<Color development>
Printing on a recording medium (trade name: PR-101; manufactured by Canon Inc.) at a temperature of 23 ° C. and a relative humidity of 55%, with a recording density of 4,800 dpi × 2,400 dpi, an ejection amount of 2.5 pl, and 100% duty. did. The reflection density of the printed matter was measured using Spectrolino (manufactured by GretagMacbeth). The evaluation criteria are as follows, and the results are shown in Table 2. Note that the standard magenta dye single color is a case where the same ink as the ink of Comparative Example 3 is used except that only 3.5 parts of each xanthene dye used in the above-described examples is used as a colorant. Means. That is, the evaluation was performed based on the difference (ΔC) between the reflection density of the printed matter obtained using this magenta dye-only ink and the reflection density of the printed matter obtained using each ink.

(Evaluation criteria)
AA: ΔC ≧ 1.5 compared to a single magenta dye color
A: Compared with a magenta dye single color, 1.5> ΔC ≧ 1.0
B: 1.0> ΔC ≧ 0.5 compared with a single magenta dye color
C: 0.5> ΔC ≧ 0 compared with a single color of magenta dye
D: ΔC <0 compared to a single magenta dye color

<Light resistance>
Using each ink, under conditions of a temperature of 23 ° C. and a relative humidity of 55%, a recording density of 4,800 dpi × 2,400 dpi on a recording medium (trade name: PR-101; manufactured by Canon), an ejection amount of 2.5 pl, 50 Printed in% duty. After that, it is naturally dried for 24 hours under conditions of a temperature of 23 ° C. and a relative humidity of 55%, and is put into a xenon test apparatus (trade name: XL-750 (manufactured by Suga Test Instruments)). For 168 hours in an atmosphere of 100 klx. First, the reflection density of the printed matter was measured before and after the test using Spectrolino (manufactured by GretagMacbeth). Next, by using the obtained reflection density, the density residual ratio after the test ((reflection density after exposure / reflection density before exposure) × 100 [%]) was calculated and evaluated. And it evaluated on the following evaluation criteria, and the result was shown in Table 2.

(Evaluation criteria)
A: Concentration residual ratio is 70% or more A: Concentration residual ratio is 60% or more and less than 70% B: Concentration residual ratio is 50% or more and less than 60% C: Concentration residual ratio is 40% or more and less than 50% D: Concentration residual ratio Is less than 40%

It is a schematic explanatory drawing of the liquid storage container which is an ink cartridge suitable for recording using the ink of this invention. It is a schematic explanatory drawing of the liquid storage container which is an ink cartridge suitable for recording using the ink of this invention.

Claims (6)

An ink comprising a copper phthalocyanine dye, wherein the ink contains at least one xanthene dye represented by the following general formula (1).

(In the formula (1), Z _{1 to} Z ₄ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkoxy group, a trifluoromethyl group, a carboxyl group, a sulfonic acid group, or may be substituted. Represents any one selected from amide groups, M represents any one selected from a hydrogen atom, an alkali metal ion, and an ammonium ion.) The ink according to claim 1, wherein the xanthene dye of the general formula (1) is a xanthene dye represented by the general formula (2).

(In the formula (2), Z ₅ and Z ₆ represents a carboxyl group, and each Z ₇ and Z ₈ independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an alkoxy group, a trifluoromethyl group, This represents any one selected from a carboxyl group, a sulfonic acid group, and an optionally substituted amide group, and M represents any one selected from a hydrogen atom, an alkali metal ion, and an ammonium ion.)   The ink according to claim 1 or 2, wherein the ratio (A: B) of the xanthene dye content (A) and the copper phthalocyanine dye content (B) is 0.2: 1 to 4: 1.   4. An ink set comprising at least a combination of any ink selected from cyan, magenta, and yellow and blue ink used for ink jet recording, wherein the blue ink is any one of claims 1 to 3. An ink set, which is the ink described in 1.   An inkjet recording method for recording on a recording medium by ejecting ink from an orifice in accordance with a recording signal, wherein the ink is the ink according to any one of claims 1 to 3. Recording method.   4. An ink cartridge comprising an ink container that contains ink, wherein the ink is the ink according to claim 1.

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