JP5871199B2 - Light blue ink composition - Google Patents

Description

Background of the Invention

The present invention relates to a light blue ink composition, and more particularly to a light blue ink composition capable of realizing a good recorded image.

In recent years, it has been practiced to form a color image by an ink jet recording method using a plurality of color ink compositions to obtain a recorded matter. In general, a color image is formed by three colors, ie, a yellow ink composition, a magenta ink composition, and a cyan ink composition, and further, if desired, four colors including a black ink composition. In some cases, color images are formed with six colors obtained by adding a light cyan ink composition and a light magenta ink composition to these four colors, or seven colors obtained by further adding a dark yellow ink composition. A combination of two or more ink compositions is an ink set.

  In the ink composition used for forming the color image described above, the ink composition of each color itself has a good color developability, and a good intermediate color is obtained when a plurality of color ink compositions are combined. It is required that the color can be developed and that the obtained recorded matter does not discolor during storage.

  More recently, in “photo quality” printing by color inkjet printers, the head, ink composition, recording method, and media have been continuously improved, and the resulting image quality is comparable to “silver salt photography”. , "Like photo". On the other hand, improvements in the ink composition and media have improved the storability of recorded images obtained using a color ink jet printer. However, the deterioration of the image is caused by an oxidizing gas present in the environment. For example, the color fading or discoloration of the image proceeds due to oxidation by ozone or the like. Therefore, in order to further improve the storability of the recorded image, it is desired to improve the light resistance and ozone resistance of the image formed by the ink composition. For this reason, various studies have been made to improve the light resistance and ozone resistance of ink-jet recorded matter. Until now, the ozone resistance performance of colorants (coloring materials) used in ink compositions has been particularly improved. (See, for example, International Publication WO02 / 060994 (Patent Document 1) and JP-A-2002-371214 (Patent Document 2)).

  In addition, an ink set capable of recording an image with good ozone resistance on a recording medium, an ink cartridge containing the ink set, a recording method using the ink set, and the ink set so far A recorded matter has been proposed (see, for example, JP-A-2005-105135 (Patent Document 3)).

  On the other hand, regarding a light blue ink composition, Japanese Patent Application Publication No. 2005-511350 (Patent Document 4) proposes a method for inkjet printing a digital image on a cloth, and is one of the inks used for the printing. Although light blue is described as, the composition and characteristics of the ink used for light blue are not described at all.

  Japanese Patent Laid-Open No. 2003-221527 (Patent Document 5) proposes an ink set for inkjet recording capable of realizing a color image having a wide range of colors, image reproducibility, and weather resistance. Although a hue angle and saturation are defined for one blue ink, it is difficult to use as a light blue ink composition.

Further, JP 2001-181987 (Patent Document 6) discloses C.I. I. Although the hue (L ^* a ^* b ^* ) of the printed matter of the ink using the pigment of Pigment Blue 15: 6 is disclosed, it is difficult to use it as a light blue ink composition.

Up to now, a total of four color ink sets of a yellow ink composition, a magenta ink composition, a cyan ink composition, and a black ink composition have been provided, and an image was formed using this ink set. In some cases, further improvement in graininess has been desired. On the other hand, in addition to the above four color ink sets of the yellow ink composition, the magenta ink composition, the cyan ink composition, and the black ink composition, a total of six colors including the light magenta ink composition and the light cyan ink composition were used. In general, when an image is formed, in addition to the case where an image is formed using the above four color ink sets, the graininess is improved. However, since a total of six colors are used, the cost is reduced. Due to the increase, further improvement in cost has been desired.
Therefore, there is a demand for an ink composition that can realize an ink set that is excellent in terms of cost while realizing an image having good graininess.

International Publication WO02 / 060994 JP 2002-371214 A JP-A-2005-105135 JP 2005-511350 A JP 2003-221527 A Japanese Patent Laid-Open No. 2001-181987

The inventors of the present invention are a light blue ink composition comprising a specific anthrapyridone dye and a specific copper phthalocyanine dye, and a spectroscopic analysis of a 1000-fold diluted solution of the light blue ink composition in water is now available. The light blue ink composition in which the L ^* a ^* b ^* color system L ^* value calculated from the characteristics falls within a specific range is not only light and gas resistant, but also has granularity, color reproducibility, and image quality. The knowledge that a recorded image excellent in sharpness was realizable was acquired. The present invention is based on these findings.

  Accordingly, an object of the present invention is to provide a light blue ink composition capable of realizing a recorded image excellent in graininess, color reproducibility, and image sharpness in addition to light resistance and gas resistance.

（式中、Ｍ^１は、水素原子、ＮＨ_４、またはＮａを表し、Ｒ^１は、水素原子、置換されてもよいアルキル基、置換されてもよいアリール基、または置換されてもよいベンゾイル基を表し、Ｒ^２は、水素原子または置換されてもよいアルキル基を表し、Ｒ^３は、水素原子、ハロゲン原子、または置換されてもよいアルキル基を表し、Ｒ^４は、水素原子、置換されてもよいＮＨ_４、または置換されてもよいスルホン酸基を表し、Ｒ^５はアシル基または下記式(II)を表す：

（式中、ＸおよびＹは、それぞれ独立して、塩素原子、水酸基、アミノ基、モノエタノールアミノ基、ジエタノールアミノ基、モルホリノ基、アニリノ基、またはフェノール基を表し、これらの基は、各々水素原子の部分が一種または二種以上の置換基により置換されていてもよい））、

（式中、Ｒ^ａは、水素原子、アルカリ金属、またはＮＨ₄を表し、Ｒ^ｂは、アルカリ金属またはＮＨ₄を表し、Ｒ^ｃは、水素原子、置換されてもよいアルキル基、または置換されてもよいアリール基を表し、また、ｋ、ｌ、ｎはそれぞれ０〜３、ｍは１〜４の自然数であり、かつｋ＋ｌ＋ｍ＋ｎ＝４である）。 The ink composition according to the present invention is a light blue ink composition comprising an anthrapyridone dye represented by the following formula (I) and a copper phthalocyanine dye represented by the following formula (VI): The light blue ink composition has an L ^* a ^* b ^* color system L ^* value in the range of 70 to 97 calculated from the spectral characteristics of a 1000-fold diluted solution of the light blue ink composition in water. :

(In the formula, M ¹ represents a hydrogen atom, NH ₄ , or Na, and R ¹ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted benzoyl group. R ² represents a hydrogen atom or an optionally substituted alkyl group, R ³ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group, and R ⁴ represents a hydrogen atom or a substituted alkyl group. Represents an optionally substituted NH ₄ or an optionally substituted sulfonic acid group, and R ⁵ represents an acyl group or the following formula (II):

(In the formula, X and Y each independently represent a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group, or a phenol group, and these groups each represent hydrogen. The atom part may be substituted by one or more substituents)),

(In the formula, R ^a represents a hydrogen atom, an alkali metal, or NH ₄ , R ^b represents an alkali metal or NH ₄ , and R ^c represents a hydrogen atom, an optionally substituted alkyl group, or a substituted group. And k, l, and n are each 0 to 3, m is a natural number of 1 to 4, and k + l + m + n = 4).

  According to the present invention, it is possible to provide a light blue ink composition capable of realizing a recorded image excellent in graininess, color reproducibility, and image sharpness in addition to light resistance and gas resistance.

Detailed description of the invention

An ink composition according to the present invention is a light blue ink composition comprising an anthrapyridone dye represented by the above formula (I) and a copper phthalocyanine dye represented by the above formula (III), The light blue ink composition has an L ^* a ^* b ^* color system L ^* value in the range of 70 to 97 calculated from the spectral characteristics of a 1000-fold diluted solution of the light blue ink composition in water. Hereinafter, each ink composition and each component in the ink composition will be described.

<Light blue ink composition>
In the ink composition according to the present invention, the L ^* value of the L ^* a ^* b ^* color system calculated from the spectral characteristics of a 1000-fold diluted solution with water is in the range of 70 to 97, preferably 70 to Within the range of 80. By setting this range, in addition to light resistance and gas resistance, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized.

In the ink composition according to the present invention, the hue angle of the L ^* a ^* b ^* color system calculated from the spectral characteristics of a 1000-fold diluted solution with water is not particularly limited as long as the effect of the present invention is exhibited, but preferably 270. It is in the range of ° to 330 °. The hue angle is more preferably in the range of 280 to 320 °. By setting this range, in addition to light resistance and gas resistance, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized.

Furthermore, in the ink composition according to the present invention, the C ^* value of the L ^* a ^* b ^* color system calculated from the spectral characteristics of a 1000-fold diluted solution with water is preferably in the range of 5 to 40, and more Preferably, it exists in the range of 20-40. By setting this range, in addition to light resistance and gas resistance, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized.

  The ink composition according to the present invention preferably has at least one absorption maximum in the wavelength range of 540 to 600 nm and 600 to 650 nm, more preferably 540 to 570 nm and 600 to 630 nm, respectively, in spectroscopic analysis. Each has at least one absorption maximum within the range. By setting it within this range, it is possible to realize a recorded image having further excellent color reproducibility and light resistance.

In the present invention, the hue angle, saturation (C ^* value), and lightness (L ^* value) of the ink composition are standardized by CIE (Commission International del'Eclairage), and in JIS (ie, JIS Z 8729). It can be defined by the color difference display method by the L ^* a ^* b ^* color system adopted.

Here, the “L ^* a ^* b ^* color system L ^* value calculated from the spectral characteristics of a 1000-fold diluted solution in water” of the ink composition means that the target ink composition is water. The diluted solution obtained was diluted 1000 times on a volume basis, and the obtained diluted solution was subjected to spectroscopic analysis using a spectrophotometer (use cell: quartz cell having an optical path length of 1 cm). From the result, L ^* a ^* b of the diluted solution was determined. ^* L ^* value in the color system is calculated, and a ^* value and b ^* value are also calculated. The “L ^* a ^* b ^* hue angle of the color system calculated from the spectral characteristics of a 1000-fold diluted solution in water” can be determined from these a ^* and b ^* values as follows. At this time, as water used for dilution, ion exchange water, ultrafiltration water, reverse osmosis water, pure water such as distilled water, or ultrapure water can be used.

Here, the hue angle is obtained as follows.
Hue angle = 360 + tan (b ^* / a ^* ) When a ^* > 0, b ^* <0
360-tan (b ^* / a ^* ) When a ^* <0, b ^* <0

On the other hand, the saturation (C ^* value) is calculated from the following equation (i) and represents a distance from the origin ((a ^* , b ^* ) = (0, 0)).
Saturation (C ^* value) = ((a ^* ) ² + (b ^* ) ² ) ^1/2 (i)

  The absorption maximum in the spectral analysis of the ink composition according to the present invention can be calculated by confirming the shape of the absorption spectrum curve in the same wavelength region and obtaining the maximum wavelength of the maximum portion of the spectrum curve.

<Colorant>
Anthrapyridone Dye The ink composition of the present invention contains an anthrapyridone dye represented by the above formula (I).

As a preferred group of anthrapyridone dyes of the present invention, in the above formula (I),
M ¹ represents NH ₄ or Na;
R ¹ represents a hydrogen atom or an optionally substituted benzoyl group (preferably, a benzoyl group substituted with a sulfonic acid group (which may be substituted with NH ₄ or Na)),
R ² represents an optionally substituted alkyl group (preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group),
R ³ represents a hydrogen atom,
R ⁴ represents an optionally substituted sulfonic acid group (preferably a sulfonic acid group substituted with NH ₄ or Na),
R ⁵ represents the above formula (II) (preferably, in the formula (II), X and Y are each independently a hydroxyl group, amino group, anilino group, or phenol group (more preferably a carboxyl group (this carboxyl The group may be substituted with NH ₄ or Na)), and each of these groups may be substituted with one or more substituents on each hydrogen atom. ) Are represented.

According to a preferred embodiment of the ink composition of the invention, the anthrapyridone dye represented by the formula (I) is a compound in which M ¹ is NH ₄ in the formula (I), and M ¹ is Na. It is preferable that a certain compound is mixed, and the anthrapyridone dye represented by the above formula (I) is (a compound in which M ¹ is NH ₄ ): (a compound in which M ¹ is Na) = 6: More preferably, it is a compound mixed in a content ratio (molar ratio) of 4 to 8: 2, (a compound in which M ¹ is NH ₄ ) :( a compound in which M ¹ is Na) = 7: 3 It is even more preferable that the compounds are mixed at a content ratio (molar ratio).

（式中、Ｍ^２は、水素原子、ＮＨ_４、またはＮａを表し、Ｒ^６は、水素原子、置換されてもよいアルキル基、置換されてもよいアリール基、または置換されてもよいベンゾイル基を表し、Ｒ^７は、水素原子または置換されてもよいアルキル基を表し、Ｒ^８は、水素原子、ハロゲン原子、または置換されてもよいアルキル基を表し、Ｒ^９は、水素原子、置換されてもよいＮＨ_４、または置換されてもよいスルホン酸基を表し、さらにＡは、アルキレン基、フェニレン基を含有するアルキレン基、または下記式(V)：

（Ｒ¹⁰は水素原子またはアルキル基を表す）
で表される基を表す。さらにＺは、塩素原子、水酸基、アミノ基、モノエタノールアミノ基、ジエタノールアミノ基、モルホリノ基、アニリノ基、またはフェノール基を表し、これらの基は、各々水素原子の部分が一種または二種以上の置換基により置換されていてもよい）。 According to a preferred embodiment of the present invention, there is provided an ink composition in which the anthrapyridone dye represented by the formula (I) is a compound represented by the following formula (IV):

(In the formula, M ² represents a hydrogen atom, NH ₄ , or Na, and R ⁶ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted benzoyl group. R ⁷ represents a hydrogen atom or an optionally substituted alkyl group, R ⁸ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group, and R ⁹ represents a hydrogen atom or a substituted alkyl group. NH ₄ which may be substituted, or a sulfonic acid group which may be substituted, and A represents an alkylene group, an alkylene group containing a phenylene group, or the following formula (V):

(R ¹⁰ represents a hydrogen atom or an alkyl group)
Represents a group represented by Z represents a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group, or a phenol group, and these groups each have one or more hydrogen atom portions. Optionally substituted by a substituent).

As a preferred group of anthrapyridone dyes of the present invention, in the above formula (IV),
M ² represents NH ₄ or Na;
R ⁶ represents an optionally substituted benzoyl group (preferably a benzoyl group substituted with a sulfonic acid group, which may be substituted with NH ₄ or Na), and R ⁷ is substituted An alkyl group (preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group),
R ⁸ represents a hydrogen atom,
R ⁹ represents an optionally substituted sulfonic acid group (preferably a sulfonic acid group substituted with NH ₄ or Na),
A represents an alkylene group or the above formula (V) (preferably R ¹⁰ represents a hydrogen atom), Z represents an amino group or a phenol group (more preferably, a carboxyl group (this carboxyl group is substituted with NH ₄ or Na) And a compound group representing a phenol group substituted with (optionally).

According to a preferred embodiment of the present invention, the ink composition preferably comprises an anthrapyridone dye in which a compound in which M ² is NH ₄ and a compound in which M ² is Na in the formula (IV) is mixed. In the formula (IV), (a compound in which M ² is NH ₄ ) :( a compound in which M ² is Na) = Anthrapyridone mixed at a content ratio (molar ratio) of 6: 4 to 8: 2 It is more preferable that the ink composition contains a dye. In the above formula (IV), the content ratio of (a compound in which M ² is NH ₄ ) :( a compound in which M ² is Na) = 7: 3 ( It is even more preferable that the ink composition contains an anthrapyridone dye mixed in a molar ratio.

（式中、Ｍ^３は、水素原子、ＮＨ_４、またはＮａを表し、Ｂはアルキレン基を表し、ｎは１または２を表す）。 According to a more preferred embodiment of the present invention, there is provided an ink composition wherein the anthrapyridone dye represented by the above formula (I) or (IV) is a compound represented by the following formula (VI):

(Wherein M ³ represents a hydrogen atom, NH ₄ , or Na, B represents an alkylene group, and n represents 1 or 2).

As a preferred group of anthrapyridone dyes of the present invention, M ^{3 in the} above formula (VI) represents NH ₄ or Na,
B represents an alkylene group (preferably an ethylene group),
A compound group in which n = 2 is exemplified.

According to a preferred embodiment of the present invention, the ink composition preferably includes an anthrapyridone dye in which a compound in which M ³ is NH ₄ and a compound in which M ³ is Na in the formula (VI) is mixed. In the above formula (VI), (a compound in which M ³ is NH ₄ ) :( a compound in which M ³ is Na) = Anthrapyridone mixed at a content ratio (molar ratio) of 6: 4 to 8: 2 It is more preferable that the ink composition contains a dye, and in the above formula (VI), (compound in which M ³ is NH ₄ ) :( compound in which M ³ is Na) = 7: 3 content ratio ( It is even more preferable that the ink composition contains an anthrapyridone dye mixed in a molar ratio.

（式中、Ｍ^４が、水素原子、ＮＨ_４、またはＮａを表す）。 According to a preferred embodiment of the ink composition of the invention, the anthrapyridone dye represented by the above formula (I) is a compound of the following formula (VI). By including these compounds in the ink composition of the present invention, in addition to light resistance and gas resistance, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized:

(Wherein M ⁴ represents a hydrogen atom, NH ₄ , or Na).

According to a preferred aspect of the present invention, the ink composition comprises an anthrapyridone dye in which a compound in which M ⁴ is NH ₄ and a compound in which M ⁴ is Na in the formula (VI) is mixed. In the above formula (VI), (compound in which M ⁴ is NH ₄ ) :( compound in which M ⁴ is Na) = mixed in a content ratio (molar ratio) of 6: 4 to 8: 2. More preferably, the ink composition contains an anthrapyridone dye, and in the above formula (VI), (a compound in which M ⁴ is NH ₄ ) :( a compound in which M ⁴ is Na) = 7: 3 It is even more preferable that the ink composition contains an anthrapyridone dye mixed at a ratio (molar ratio).

（式中、Ｍ^５が、水素原子、ＮＨ_４、またはＮａを表す）。 According to a preferred embodiment of the ink composition of the invention, the anthrapyridone dye represented by the above formula (I) is a compound of the following formula (VIII). By including these compounds in the ink composition of the present invention, in addition to light resistance and gas resistance, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized:

(Wherein M ⁵ represents a hydrogen atom, NH ₄ , or Na).

Furthermore, according to a preferred aspect of the present invention, there is provided an ink composition comprising an anthrapyridone dye in which a compound in which M ⁵ is NH ₄ and a compound in which M ⁵ is Na are mixed in the above formula (VIII). In the above formula (VIII), (compound in which M ⁵ is NH ₄ ) :( compound in which M ⁵ is Na) = mixed in a content ratio (molar ratio) of 6: 4 to 8: 2. More preferably, the ink composition contains an anthrapyridone dye, and in the above formula (VIII), (a compound in which M ⁵ is NH ₄ ) :( a compound in which M ⁵ is Na) = 7: 3 It is even more preferable that the ink composition contains an anthrapyridone dye mixed at a ratio (molar ratio).

According to a preferred embodiment of the ink composition of the invention, the anthrapyridone dye represented by the above formula (I) is a compound of the following formula (IX). By including these compounds in the ink composition of the present invention, it is possible to realize a recorded image that maintains both the color reproducibility inherent to the colorant and the light resistance:

  The content of the anthrapyridone dye is not particularly limited as long as a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized in addition to light resistance and gas resistance. 0.1 to 4.5% by mass, preferably 2.0 to 3.0% by mass. By setting this range, in addition to light resistance and gas resistance, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized.

  Ratio (A / B) of content (A) of the anthrapyridone dye contained in the ink composition of the present invention and content (B) of the following copper phthalocyanine dye (content of magenta dye / cyan) The content of the dye) is not particularly limited as long as the effect of the present invention is exhibited, but is preferably in the range of 0.6 to 2.5. By setting this range, in addition to light resistance and gas resistance, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized.

Copper phthalocyanine dye The ink composition of the present invention contains a copper phthalocyanine dye represented by the above formula (VI).

（式中、Ｚ１、Ｚ２、Ｚ３、およびＺ４はそれぞれ以下の基である。）

The copper phthalocyanine dye used in the present invention is more preferably a compound of the following formula (X) and CI Direct Blue 199, and among them, a compound of the formula (X) is more preferable. By including this compound in the ink composition of the present invention, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized in addition to light resistance and gas resistance.

(Wherein Z1, Z2, Z3, and Z4 are the following groups, respectively)

  In the present invention, the content of the copper phthalocyanine dye contained in the ink composition is preferably 0.02 to 3.0% by mass with respect to the ink composition, and preferably 1.0 to 2.0. More preferably, it is contained by mass%. By setting this range, in addition to light resistance and gas resistance, a recorded image excellent in graininess, color reproducibility, and image sharpness can be realized.

<Water, water-soluble organic solvent, and other optional components>
The ink composition according to the present invention is represented by the dye represented by the above formula (I) and the above formula (III) as a colorant in water alone or an aqueous medium composed of water and a water-soluble organic solvent. A dye containing a humectant, a surfactant, a penetration enhancer, a viscosity modifier, a pH adjuster, and other additives as necessary.

  The ink composition in the present invention can be obtained by dissolving the above-described colorant (dye) in an appropriate solvent. As a solvent for dissolving the colorant in the ink composition, water or a mixed liquid of water and a water-soluble organic solvent is preferably used as a main solvent. As water, ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or the like can be used. From the viewpoint of long-term storage, it is preferable to use water that has been subjected to various chemical sterilization treatments such as ultraviolet irradiation and addition of hydrogen peroxide. The water content in the ink composition of the present invention is preferably 40 to 90% by mass of the ink composition, and more preferably 50 to 80% by mass.

  As described above, the ink composition in the present invention can use a water-soluble organic solvent as a solvent together with water. As the water-soluble organic solvent, those having the ability to dissolve the dye are preferable, and those having a vapor pressure smaller than that of pure water are preferable.

  Examples of the water-soluble organic solvent used in the present invention include ethylene glycol, propylene glycol, butanediol, pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, glycerin, 1, Polyhydric alcohols such as 2,6-hexanetriol, diethylene glycol, triethylene glycol and dipropylene glycol, ketones such as acetonylacetone, esters such as γ-butyrolactone and triethyl phosphate, furfuryl alcohol, tetrahydrofurfuryl Although alcohol, thiodiglycol, etc. are preferable, it is not limited to these. By using a water-soluble organic solvent together with water as the solvent of the ink composition, the ejection stability of the ink composition from the ink head can be improved, and the viscosity of the ink composition can be lowered with almost no other change. Etc. can be easily adjusted.

  In addition, at least one humectant selected from saccharides can be contained in the ink composition of the present invention. By including a moisturizing agent in the ink composition, when the ink composition is used in the ink jet recording method, it is possible to suppress moisture evaporation from the ink and moisturize the ink. As the saccharide used in the present invention, maltitol, sorbitol, gluconolactone, maltose and the like are preferable. In addition, the water-soluble organic solvent mentioned above may work as a moisturizer.

  The water-soluble organic solvent and / or humectant can be contained in the ink composition in a total amount of 5 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 5 to 20% by mass. By making these contents 5% by mass or more, good ink moisture retention can be obtained, and by making it 50% by mass or less, the viscosity of the ink composition is adjusted to a preferred viscosity for use in the ink jet recording method. can do.

  The surfactant contained in the ink composition of the present invention is not particularly limited, but a nonionic surfactant is preferable. By adding a nonionic surfactant to the ink composition, the ink composition has excellent permeability to the recording medium, and the ink composition can be quickly fixed on the recording medium during printing. Further, it is preferable that one dot recorded by the ink composition on the recording medium is as close to a perfect circle as possible, but an image formed by one dot by incorporating a nonionic surfactant in the ink composition. The roundness of the image can be increased, and the image quality of the obtained image can be improved.

  Examples of nonionic surfactants that can be used in the present invention include acetylene glycol surfactants. Specific examples of acetylene glycol surfactants include Surfinol 465, Surfinol 104 (manufactured by Air Products and Chemicals Inc.), Olphine E1010, Olphine PD001, Olphine STG (Nisshin Chemical Industry Co., Ltd.) Product name). The addition amount is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 3.0% by mass. When the addition amount is 0.1% by mass or more, sufficient penetrability can be obtained, and when the addition amount is 5.0% by mass or less, it is easy to prevent image bleeding.

  Furthermore, in addition to nonionic surfactants, the addition of glycol ethers as penetration enhancers to the ink composition improves the penetrability of the ink composition with respect to the recording medium, and when color printing is performed. At the boundary between adjacent color inks, ink bleeding (bleeding) is reduced, and a very clear image can be obtained. Therefore, it is preferable to add a penetration enhancer to the ink composition of the present invention.

  The glycol ethers used in the present invention as penetration enhancers include ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene Glycol monobutyl ether, triethylene glycol monobutyl ether and the like are preferable, but are not limited thereto. These glycol ethers are preferably contained in the ink composition in an amount of 3 to 30% by mass, more preferably 5 to 15% by mass. By making the addition amount of glycol ethers 3% by mass or more, bleeding (bleeding) between adjacent inks at the time of color printing can be effectively prevented, and further by making this addition amount 30% by mass or less, image It becomes easy to prevent the occurrence of bleeding, and the storage stability of the ink can be improved.

  Further, the ink composition of the present invention includes a pH adjuster such as triethanolamine or alkali metal hydroxide, a water-soluble polymer such as sodium alginate, a water-soluble resin, a fluorosurfactant, an antiseptic, and an antifungal agent. A material selected from a rust inhibitor, a dissolution aid, an antioxidant, an ultraviolet absorber, and the like can be added as desired. These components can be used alone or in combination of two or more. Moreover, it is not necessary to add, if it is not necessary to add. Those skilled in the art can use the preferable additive selected in a preferable amount as long as the effects of the present invention are not impaired. The dissolution aid is an additive for dissolving the insoluble matter and keeping the ink composition in a uniform solution when the insoluble matter is precipitated from the ink composition.

  Examples of the solubilizer include pyrrolidones such as N-methyl-2-pyrrolidone and 2-pyrrolidone, ureas such as urea, thiourea and tetramethylurea, allophanates such as allohanate and methyl allophanate, biuret and dimethylbiuret. And biurets such as tetramethylbiuret can be mentioned, but the invention is not limited to these. Examples of the antioxidant include L-ascorbic acid and salts thereof, but are not limited thereto.

  Examples of the antiseptic or antifungal agent include sodium benzoate, sodium pentachlorophenol, 2-pyridinethiol-1-oxide sodium, sodium sorbate, sodium dehydroacetate, and 1,2-dibenzisothiazoline-3. -ON (Avexia Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN (trade name) and the like can be exemplified, but not limited thereto.

  Examples of the pH adjuster include amines such as diethanolamine, triethanolamine, propanolamine, and morpholine, and modified products thereof, metal hydroxides such as potassium hydroxide, sodium hydroxide, and lithium hydroxide, ammonium hydroxide, Examples thereof include ammonium salts such as quaternary ammonium hydroxide (tetramethylammonium, etc.), carbonates such as potassium carbonate, sodium carbonate, lithium carbonate, and other phosphates, but are not limited thereto.

  The ink composition of the present invention is prepared by including components appropriately selected from the components described above, and the viscosity of the obtained ink composition is preferably less than 10 mPa · s at 20 ° C. Furthermore, in the present invention, the surface tension of the ink composition is preferably 45 mN / m or less at 20 ° C., and particularly preferably in the range of 25 to 45 mN / m. By adjusting the viscosity and the surface tension in this way, an ink composition having desirable characteristics for use in the ink jet recording method can be obtained. The adjustment of the viscosity and the surface tension can be performed by appropriately adjusting and selecting the addition amount of the solvent and various additives to be contained in the ink composition, the kind thereof, and the like.

  The ink composition of the present invention preferably has a pH of 7.0 to 10.5 at 20 ° C., more preferably 7.5 to 10.0. By making the pH of the ink composition at 20 ° C. 7.0 or more, it is possible to prevent the eutectoid plating of the ink jet head from being peeled off, and to stabilize the ejection characteristics of the ink composition from the ink jet head. Can do. In addition, by setting the pH of the ink composition to 10.5 or less at 20 ° C., it is possible to prevent deterioration of various members that come into contact with the ink composition, for example, members constituting an ink cartridge or an inkjet head. .

  As a method for preparing the ink composition in the present invention, for example, various components contained in the ink composition are sufficiently mixed and dissolved as uniformly as possible, followed by pressure filtration with a membrane filter having a pore size of 0.8 μm, and further. Although the method of preparing the obtained solution by deaerating using a vacuum pump can be illustrated, it is not limited to this.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these Examples.

<Preparation of ink composition>
The ink composition having the composition shown in Table 1 below was stirred at room temperature for 1 hour and then filtered through a 0.8 μm membrane filter to obtain each ink composition. The numerical values in Table 1 below represent the content (% by mass) in the ink, and Olfine E1011 is manufactured by Nissin Chemical Industry Co., Ltd.

Characteristics obtained from the diluted solution of the ink composition in water The spectral characteristics of the diluted solution in water of each light blue ink composition (ink compositions of Examples 1 to 13) were measured using a spectrophotometer (trade name U manufactured by Hitachi, Ltd.). -3000). In the measurement, ion exchange water was added to 1 ml of the ink composition to make 1000 ml, which was filled in a quartz cell having an optical path length of 1 cm and measured in a transmission mode. The L ^* a ^* b ^* value of the ink composition was determined from the measured spectral characteristics using a color analysis program (color analysis program attached to U-3000). L ^* , C ^* , and hue angle were calculated as described above. The magenta dye content / cyan dye content, L ^* , C ^* , and hue angle of each ink composition are shown in Table 2 below.

Printing test method An ink cartridge filled with a light blue ink composition (ink compositions of Examples 1 to 13) was loaded into an ink jet printer PM-G800 (manufactured by Seiko Epson Corporation), and an evaluation paper (photographic paper Crispier <high gloss) >: Seiko Epson Corporation). The ink supply method is to fill the PM-G800 ink cartridge with light blue ink and load it at the ICLC32 position on the carriage, and the PM-G800 black ink cartridge (ICBK32: Seiko Epson Corporation) and color An ink cartridge (ICC32, ICM32, ICY32: all manufactured by the same company) was loaded at a predetermined position on the carriage, and each required color ink was supplied to the head from there. On the other hand, an empty ink cartridge not filled with light blue ink was loaded at the position of ICLM32 on the carriage, and the one loaded with the black ink cartridge for PM-G800 and the color ink cartridge was used as a control. For printing, a printer driver for light blue ink was created and used.

Graininess evaluation A cyan gradation pattern was printed. Next, each printing pattern was scanned under the following conditions.
Scanner: DT-S1045AI (Dainippon Screen Mfg. Co., Ltd.)
Resolution: 1300 dpi analysis target area: 512 × 512 pixels (10 × 10 mm)
Next, the scanned image data is converted into the L ^* a ^* b ^* space, and the L ^* component image is subjected to a two-dimensional FFT (two-dimensional fast Fourier transform) and then converted into a curved coordinate system. To obtain WS (u) which is the winner spectrum of the image (see “Noise Evaluation Method of Halftone Color Image” by Imagawa et al. (Hardcopy '96, 189-192, 1996)). Further, VTF (u) indicating the visual spatial frequency characteristic was obtained by using the following equation (1) and assuming that the clear vision distance l was 300 mm.
VTF (u) = 5.05exp (-0.138πlu / 180) {1-exp (-0.1πlu / 180)} (1)
From these WS (u) and VTF (u), the graininess index was finally calculated by the following formula (2), and the graininess in each case was evaluated.
(Granularity index) = a (L ^* ) ∫ (WS (u)) ^0.5 VTF (u) du (2)
Here, a (L ^* ) which is brightness correction in the above formula (2) is a value derived from the following formula (3). This uses only the L ^* component, but there is a high correlation coefficient of 0.95 between the subjective evaluation results using 8 types of ink jet printers and 9 level gray patches of Pictrography. It is the original one that the relationship was obtained.
a (L ^* ) = ((L ^* + 16) / 116) ^0.8 (3)
From the above, for the ink compositions of the above examples, values were calculated when the graininess index of the control (when light blue ink was not used) was 1.0. These obtained values were determined according to the following criteria. In the gradation pattern printing, the portion of L ^* = 30 was used as a comparison point. The smaller the value of the graininess index, the less the graininess in the formed image and the higher the image quality.
Evaluation A: Evaluation B less than 0.7 Evaluation B: 0.7 or more and evaluation 1.0 or less C: 1.0 or more Evaluation results are shown in Table 2 below.

Evaluation of image clarity A clear image was taken with a digital camera. “A” when the image data is printed by the above printing test method, and the obtained image is felt to be much clearer than the control (when light blue ink is not used). The case where it was perceived as “B” was evaluated as “B”, and the case where it was perceived as equivalent sharpness was evaluated as “C”.
The evaluation results are shown in Table 2 below.

Evaluation of color reproducibility A patch pattern including various hues unified to a predetermined L ^* value is printed according to the above printing test method, and these are measured to obtain a ^* and b ^* values as described above. The color reproducibility at a predetermined L ^* value was determined. The color of the printed matter was measured using a colorimeter SPM-50 (manufactured by Gertag). Specifically, the evaluation L ^* values are 70, 80, and 90, and the value when the color reproduction area in the control of each example (when light blue ink is not used) is 100% is obtained, and the average of these values is obtained. “C” when the value is 100% or more and less than 120%, “B” when the average value is 120% or more and less than 140%, and “A” when the average value exceeds 140% . The evaluation results are shown in Table 2 below.

Evaluation of image light resistance Using the fluorescent light resistance tester STF-11 (trade name: manufactured by Suga Test Instruments Co., Ltd.), each of the above printed materials was tested under the conditions of 24 ° C, relative humidity 60% RH, and illuminance 70,000lux. Exposure for 18 and 24 days.
After exposure, the OD value of each printed matter is measured using a reflection densitometer (“Spectrilino” (trade name, manufactured by Gretag), and the optical density residual ratio (ROD) is calculated from the following formula. evaluated.
ROD (%) = (D / D ₀ ) x 100
D: OD after exposure test D ₀ : OD before exposure test
(Measurement conditions Light source: D50, viewing angle: 2 °)
A: When exposed to 24 days and ROD is 80% or more
B: ROD is 80% or more after 18 days exposure, and ROD is less than 80% after 24 days exposure
C: When the ROD is less than 80% after 18 days exposure, the evaluation results are shown in Table 2 below.

Evaluation of image ozone resistance Each of the above printed materials is 60 using an ozone weather meter OMS-H type (trade name, manufactured by Suga Test Instruments Co., Ltd.) under the conditions of 24 ° C., relative humidity 60% RH, and ozone concentration 10 ppm. Exposure for 80 hours. After exposure, measure the OD value of each printed matter using the same reflection densitometer used in the light resistance test under the same measurement conditions as the light resistance test. (ROD) was determined and evaluated according to the following criteria.
A: ROD is 70% or more after 80 hours exposure
B: ROD is 70% or more after 60 hours exposure. When ROD is less than 70% after 80 hours exposure
C: When the ROD is less than 70% after 60 hours exposure, the evaluation results are shown in Table 2 below.

Claims (9)

And anthrapyridone dye represented by the following formula (I), a Louis ink composition Do and a copper phthalocyanine dye represented by the following formula (X),
Before ^{L *} value of ^{the L} * ^a * ^{b *} color system calculated from spectral characteristics of 1000-fold diluted solution with water of listening ink composition I near the range of 70 to 97, wherein the anthrapyridone dye The content A of the copper phthalocyanine dye is 0.02 to 3.0% by mass, and the content molar ratio (A / B) is 0.1 to 4.5% by mass. 0.6 to 2.5, the ink composition:

(In the formula, M ¹ is a mixture of a compound of NH ₄ and a compound of Na in a molar ratio of 6: 4 to 8: 2 , wherein R ¹ is a hydrogen atom, substituted Represents an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted benzoyl group, R ² represents a hydrogen atom or an optionally substituted alkyl group, R ³ represents a hydrogen atom, a halogen atom, Represents an atom or an alkyl group which may be substituted; R ⁴ represents a hydrogen atom, NH ₄ which may be substituted or a sulfonic acid group which may be substituted; R ⁵ represents an acyl group or a group represented by the following formula (II Represents:

(In the formula, X and Y each independently represent a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group, or a phenol group, and these groups each represent hydrogen. The atom part may be substituted by one or more substituents)),

(Wherein Z1, Z2, Z3, and Z4 are the following groups, respectively)

M ¹ But NH ₄ The ink composition according to claim 1, wherein the compound and Na are mixed at a molar ratio of 7: 3. The ink composition according to claim 1 or 2 , wherein the anthrapyridone dye is a compound represented by the following formula (IV):

(In the formula, M ² represents a hydrogen atom, NH ₄ , or Na, and R ⁶ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted benzoyl group. R ⁷ represents a hydrogen atom or an optionally substituted alkyl group, R ⁸ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group, and R ⁹ represents a hydrogen atom or a substituted alkyl group. NH ₄ which may be substituted, or a sulfonic acid group which may be substituted, and A represents an alkylene group, an alkylene group containing a phenylene group, or the following formula (V):

(R ¹⁰ represents a hydrogen atom or an alkyl group)
Represents a group represented by Z represents a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group, or a phenol group, and these groups each have one or more hydrogen atom portions. Optionally substituted by a substituent). The ink composition according to any one of claims 1 to 3, wherein the anthrapyridone dye is a compound represented by the following formula (VI):

(Wherein M ³ represents a hydrogen atom, NH ₄ , or Na, B represents an alkylene group, and n represents 1 or 2). The hue angle of the L ^* a ^* b ^* color system calculated from the spectral characteristics of a 1000-fold diluted solution with water is in the range of 270 ° to 330 °, according to any one of claims 1 to 4. Ink composition. The ink according to any one of claims 1 to 4, wherein the hue angle of the L ^* a ^* b ^* color system calculated from the spectral characteristics of a 1000-fold diluted solution in water is in the range of 280 to 320 °. Composition. The ink according to any one of claims 1 to 6, wherein the C ^* value of the L ^* a ^* b ^* color system calculated from the spectral characteristics of the 1000-fold diluted solution in water is in the range of 5 to 40. Composition.   The ink composition according to any one of claims 1 to 7, wherein a content of the anthrapyridone dye is in a range of 0.1 to 4.5 mass% with respect to the ink composition.   The ink composition according to any one of claims 1 to 8, wherein a content of the copper phthalocyanine dye is 0.02 to 3.0 mass% with respect to the ink composition.