JP4761022B2 - Ink composition, ink cartridge, ink jet recording method and recorded matter - Google Patents

Description

  The present invention relates to an ink composition capable of improving the storage stability (gas resistance) of an image to be produced, and in particular, an ink containing a phthalocyanine cyan dye that can effectively prevent discoloration of an image. Relates to the composition.

  Conventionally, an ink composition using a phthalocyanine-based cyan dye has been widely used as an ink composition for developing an excellent cyan color image. In addition, recently, an ink composition that develops such an image is used together with one or more ink compositions for developing other colors to form an image, and the resulting image (color) It is widespread that images are posted indoors.

  However, in the ink composition using the phthalocyanine cyan dye, the phthalocyanine cyan dye is inferior in resistance to oxidizing gases such as ozone, nitrogen oxide and sulfur oxide present in the air, particularly ozone resistance. Therefore, when an image of a plurality of colors is formed together with the ink composition of other colors and the image is posted indoors, there is a problem that the image formed from the cyan dye is rapidly changed in color.

  In order to prevent such discoloration of phthalocyanine, various ink compositions have been developed. For example, WO99 / 50363 discloses a cyanide comprising a copper phthalocyanine cyan dye, an imidazole derivative, an antioxidant, a sugar, a naphthalene-1-sulfonic acid having a hydroxyl group or an amino group at the 4-position. An ink composition has been disclosed as means for improving light resistance (Patent Document 1). However, this ink composition has not been evaluated for resistance to ozone gas, and there are hydroxyl groups and amino groups in the molecules of the components used, resulting in an image formed by nitrogen oxides (NOx gas). There is a problem of causing a greening or blackening phenomenon.

  In order to solve this problem, the present inventors have conducted intensive research. As a result, by adding a specific aromatic sulfonic acid or / and a salt thereof to an ink composition using a phthalocyanine-based cyan dye, It has been found that the ozone resistance of a recorded image can be effectively improved without causing discoloration (Japanese Patent Application No. 2003-341633). However, as a result of further research, in the ink composition using the additive, the additive in the ink is sometimes deposited on the surface of the image while the recorded image is stored at room temperature for a long period of time. I found out that sometimes This was seen, for example, when the sodium salt or potassium salt of the aromatic compound such as naphthalene-1,5-disulfonic acid 2Na salt was used. When the amount of the aromatic sulfonate contained in the ink is small, there is no phenomenon that the additive is precipitated, but there is a problem that the ozone resistance is lowered as the amount of the additive is reduced.

Furthermore, when printing was performed in a high-temperature and high-humidity environment, bronzing sometimes occurred. Also in this case, the bronzing phenomenon is not observed when the amount of the aromatic sulfonate contained in the ink is small, but there is a problem that the ozone resistance decreases as the amount of the additive decreases.
WO99 / 50363

  Accordingly, an object of the present invention is to provide an ink capable of improving the indoor storage stability (gas resistance) of an image produced by an ink composition using a phthalocyanine cyan dye without causing additive precipitation and bronzing. It is to provide a composition.

  As a result of diligent research, the present inventors have obtained knowledge that an ink composition containing a specific component together with a phthalocyanine cyan dye can achieve the above object.

This invention is made | formed based on the said knowledge, and provides the following invention.
An ink composition comprising at least water, a phthalocyanine cyan dye, and a lithium salt of an aromatic compound having a sulfo group represented by the following general formula (2) .

  The ink composition of the present invention has an excellent effect that the indoor storage stability (gas resistance) of an image obtained can be improved without causing additive precipitation and bronzing.

Hereinafter, the ink composition of the present invention will be described in detail based on preferred embodiments thereof.
(First embodiment)
The ink composition according to the first embodiment of the present invention includes at least water, a phthalocyanine cyan dye, and an aromatic compound having a sulfo group represented by the following general formula (1) and / or (2). And lithium salt.

  The ink composition of the first embodiment has such a configuration, and can thereby effectively prevent early fading of a cyan image without causing problems such as precipitation of additives and generation of bronzes. . As a result, the quality of the created image can be maintained in a good state for a long time.

  The ink composition of the first embodiment is represented by at least a phthalocyanine-based cyan dye and the general formula (1) and / or (2) in water or an aqueous medium composed of water and a water-soluble organic solvent. It contains a lithium salt of an aromatic compound having a sulfo group, and may contain a humectant, a viscosity adjuster, a pH adjuster and other additives as necessary.

The cyan dye used in the ink composition of the first embodiment is not particularly limited as long as it is a phthalocyanine-based cyan dye, but a copper phthalocyanine-based dye can provide a more improved effect.
Preferred examples of the copper phthalocyanine dye include dyes represented by the following formula (3).

  The cyan dye suitably used in the ink composition of this embodiment, that is, the copper phthalocyanine cyan dye represented by the above formula (3) will be described in detail.

  As the above copper phthalocyanine cyan dye, C.I. I. Direct blue 86, 87, 199 etc. are mentioned.

  These dyes can be used alone or in combination, and can also be used in combination with dyes other than those shown above.

  Further, as a phthalocyanine cyan dye, use of a dye having a maximum absorption peak at a wavelength of 590 to 650 nm, particularly 590 to 615 nm, particularly 590 to 605 nm as an absorption spectrum in the visible region (400 to 800 nm) improves the ozone resistance ability. This is preferable.

The phthalocyanine cyan dye particularly has a sulfo group which is an ionic hydrophilic group, for example, SO ₃ R ¹ or SO ₃ R ² in the formula (3), and in these R ¹ and R ² , the bronze of the printed image Lithium ions are most preferable from the viewpoint of suppression of the phenomenon.

  The content of the phthalocyanine cyan dye is appropriately determined depending on the kind of the dye, the kind of the solvent component, etc., but is preferably 0.1 to 10% by weight, more preferably 0.5 to 5% based on the total weight of the ink composition. It is in the range of 5% by weight. By setting the content to 0.1% by weight or more, it is possible to ensure color developability or image density on the recording medium, and by setting the content to 10% by weight or less, it becomes easy to adjust the viscosity of the ink composition, and discharge reliability and clogging properties. Such characteristics can be easily secured.

  In the ink composition of the present embodiment, the discoloration seen when printing is performed using the ink composition containing the phthalocyanine cyan dye (the phthalocyanine cyan dye is inferior in gas resistance, in particular, ozone resistance). In order to suppress the phenomenon caused by (ii), at least one lithium salt of an aromatic compound having a specific sulfo group is contained.

  In the present embodiment, the lithium salt of an aromatic compound having a specific sulfo group is used in combination with the above-described phthalocyanine cyan dye, so that the ozone gas can be produced without causing problems such as precipitation of additives and generation of bronze. This is a technique in which the color fading of the image is suppressed and the color fading resistance of the image is drastically improved.

  In the ink composition of the present embodiment, the discoloration color seen when printing using an ink composition containing a phthalocyanine cyan dye (because the phthalocyanine cyan dye is inferior in gas resistance, particularly ozone resistance) In order to reduce or eliminate the phenomenon considered to occur without causing additive precipitation and bronzing, the aromatic compound having a sulfo group represented by the general formula (1) and / or (2) is used. Contains at least one lithium salt.

  Although the details of the operation of the ink composition of the present embodiment are unknown, the aromatic sulfonic acid compound having one or more sulfo groups is represented by the general formula (1) and / or (2). By selectively using the lithium salt of the compound, the water solubility of the aromatic compound can be improved, and as a result, precipitation of the aromatic compound on the surface of the recording medium and bronzing of the printed matter can be prevented.・ I think that the effect of deterrence appears. As a result, it is possible to improve the gas resistance, particularly ozone resistance of the printed matter without any trouble.

This embodiment is derived from NO _x gas by using a lithium salt of an aromatic compound having a sulfo group represented by the general formula (1) and / or (2) in combination with a phthalocyanine cyan dye. This prevents the discoloration of the image derived from ozone gas without causing any greening or blackening, or precipitation of additives or bronzing, and dramatically improves the discoloration resistance of the image. It is.

  In the present embodiment, the cyan ink composition is, of course, any ink composition that contains water, a phthalocyanine cyan dye, and at least one lithium salt of an aromatic compound having a sulfo group. Even an ink composition having a color different from cyan, such as a black ink composition, can effectively prevent the discoloration color seen when solid printing is performed. In order to produce these various ink compositions, they can be used in combination with other conventionally known dyes.

  The lithium salt of the aromatic compound having a sulfo group represented by the general formula (1) and / or (2) is any lithium salt of an aromatic compound having at least one sulfo group in the molecular structure. However, one having two or more sulfo groups, particularly 1,3-benzenedisulfonic acid, naphthalene-1,5-disulfonic acid, naphthalene-1,6-disulfonic acid, naphthalene-2,6-disulfonic acid, At least one selected from the group consisting of lithium salts of naphthalene-2,7-disulfonic acid and naphthalene-1,3,6-trisulfonic acid, the resulting image has ozone resistance, additive precipitation suppression and bronze It is preferable in terms of improvement in suppression.

  The lithium salt of the aromatic compound having a sulfo group may be added in the form of the salt and contained in the ink composition. Also, the lithium compound and lithium salt having the sulfo group may be formed. It is also possible that the base that can be used for the ink is added separately and contained in the ink composition.

  The content of the lithium salt of the aromatic compound having a sulfo group is appropriately determined depending on the type of the lithium salt of the aromatic compound having the sulfo group, the type of the dye, the type of the solvent component, etc. Preferably it is 0.1 to 10 weight% with respect to a weight, More preferably, it is the range of 0.5 to 10 weight%.

  In the ink composition of the present embodiment, the content ratio (the former: latter) of the phthalocyanine cyan dye and the lithium salt of the aromatic compound having a sulfo group effectively improves the gas resistance and the ink composition. From the viewpoint of ensuring reliability, it is preferably in the range of 1: 0.1 to 1:10, particularly 1: 0.2 to 1: 5.

  In order to stably dissolve the amounts of the phthalocyanine cyan dye and the lithium salt of the aromatic compound having a sulfo group, the pH (20 ° C.) of the ink composition is preferably 8.0 or more. In consideration of material resistance with various members in contact with the ink composition, the pH of the ink composition is preferably 10.5 or less. In order to make these matters better compatible, it is more preferable to adjust the pH of the ink composition to 8.0 to 10.5, particularly 8.5 to 10.0.

The ink composition of the present embodiment can further contain a humectant selected from a water-soluble organic solvent and / or saccharide having a vapor pressure lower than that of pure water.
By including the humectant, the ink can be moisturized by suppressing evaporation of moisture in the ink jet recording system. In addition, if it is a water-soluble organic solvent, the viscosity can be easily changed without improving ejection stability or changing ink characteristics.

The water-soluble organic solvent refers to a medium having an ability to dissolve a solute, and is selected from organic and water-soluble solvents having a vapor pressure smaller than that of water. Specifically, ethylene glycol, propylene glycol, butanediol, pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, glycerin, 1,2,6-hexanetriol, diethylene glycol Desirable are polyhydric alcohols such as triethylene glycol and dipropylene glycol, ketones such as acetonyl acetone, esters such as γ-butyrolactone and triethyl phosphate, furfuryl alcohol, tetrahydrofurfuryl alcohol, thiodiglycol and the like. .
As the saccharide, maltitol, sorbitol, gluconolactone, maltose and the like are preferable.

  The humectant is preferably added in the range of 5 to 50% by weight, more preferably 5 to 30% by weight, and still more preferably 5 to 20% by weight with respect to the total amount of the ink composition. If it is 5% by weight or more, moisture retention can be obtained, and if it is 50% by weight or less, it is easy to adjust the viscosity used for inkjet recording.

The ink composition of the present embodiment preferably contains a nitrogen-containing organic solvent as a solvent. Examples of the nitrogen-containing organic solvent include 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidone, N-methyl-2-pyrrolidone, and ε-caprolactam. Among them, 2-pyrrolidone is preferably used. be able to. They can be used alone or in combination of two or more.
The content is preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight. When the content is 0.5% by weight or more, the solubility of the coloring material in the present invention can be improved by adding the content, and when the content is 10% by weight or less, various ink compositions come into contact therewith. The material resistance with the member is not deteriorated.

  In addition, the ink composition of the present embodiment includes a nonionic surfactant as an additive that is effective in obtaining rapid fixing (penetration) of the ink and maintaining the roundness of one dot. It is preferable.

  Examples of nonionic surfactants that can be used in the present embodiment include acetylene glycol surfactants. Specific examples of the acetylene glycol surfactants include Surfinol 465, Surfinol 104 (manufactured by Air Products and Chemicals Inc.), Olfin E1010, Olphine PD001, Olphine STG (manufactured by Nissin Chemical Industry Co., Ltd.). Product name). The addition amount is preferably 0.1 to 5% by weight, more preferably 0.5 to 2% by weight. When the addition amount is 0.1% by weight or more, sufficient penetrability can be obtained, and when the addition amount is 5% by weight or less, it is easy to prevent image blurring.

  The ink composition of the present embodiment preferably further contains a penetration enhancer from the viewpoint that the permeability can be improved. By adding glycol ethers as the penetration enhancer, the penetrability is further increased and the bleed at the boundary with the adjacent color ink is reduced when color printing is performed, thereby obtaining a very clear image. Can do.

  As glycol ethers, 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 Etc. The addition amount is 3 to 30% by weight, preferably 5 to 15% by weight. If the amount added is less than 3% by weight, the effect of preventing bleeding may not be obtained. If the amount exceeds 30% by weight, not only the image will bleed, but also oily separation will occur, so the dissolution aid for these glycol ethers will be required, which will increase the viscosity of the ink. Becomes difficult.

  Furthermore, the ink composition of the present embodiment includes a pH adjuster such as triethanolamine or alkali metal hydroxide, a hydrotrope such as urea and its derivatives, and a water-soluble polymer such as sodium alginate, as necessary. Water-soluble resins, fluorine-based surfactants, fungicides, rust inhibitors, preservatives and the like may be added.

  As a method for preparing the ink composition of the present embodiment, for example, each component is sufficiently mixed and dissolved, pressure filtered through a membrane filter having a pore size of 0.8 μm, and then degassed using a vacuum pump. and so on.

(Second Embodiment)
The ink composition according to the second embodiment of the present invention includes at least water, a phthalocyanine cyan dye, an aromatic compound having a sulfo group represented by the following general formula (4) and / or (5), and And / or a salt thereof.

  Since the ink composition of the second embodiment has such a configuration, it can effectively prevent early fading of a cyan image without causing additive precipitation, and is thus created. It is possible to improve the indoor storage stability (gas resistance) of an image without problems.

  The ink composition of the second embodiment is represented by at least a phthalocyanine cyan dye and the general formula (4) and / or (5) in water or an aqueous medium composed of water and a water-soluble organic solvent. It contains an aromatic compound having a sulfo group and / or a salt thereof, and may contain a moisturizing agent, a viscosity adjusting agent, a pH adjusting agent and other additives as necessary.

  The cyan dye used in the ink composition of the second embodiment is not particularly limited as long as it is a phthalocyanine cyan dye. The cyan dye used in the ink composition of the second embodiment is the same as the cyan dye used in the ink composition of the first embodiment described above. Therefore, for the details of the cyan dye in the present embodiment, the matters relating to the cyan dye in the first embodiment described above are appropriately applied.

  In the ink composition of the present embodiment, the discoloration seen when printing is performed using the ink composition containing the phthalocyanine cyan dye (the phthalocyanine cyan dye is inferior in gas resistance, in particular, ozone resistance). In order to suppress the phenomenon caused by (3), at least one specific aromatic compound having 3 or more sulfo groups and / or a salt thereof is contained.

  In the present embodiment, the use of the specific aromatic compound having three or more sulfo groups and / or a salt thereof in combination with the phthalocyanine cyan dye described above makes it possible to generate ozone gas without causing problems such as additive precipitation. The color fading of the image is suppressed, and the fading resistance of the image is drastically improved.

  In the ink composition of the present embodiment, the discoloration color seen when printing using an ink composition containing a phthalocyanine cyan dye (because the phthalocyanine cyan dye is inferior in gas resistance, particularly ozone resistance) In order to reduce or eliminate the phenomenon considered to occur without causing additive precipitation, an aromatic compound having three or more sulfo groups represented by the general formula (4) and / or (5) and At least 1 type of the salt is contained.

  Although the details of the action of the ink composition of the present embodiment are unknown, the aromatic compound having a sulfo group and / or a salt thereof is represented by the general formula (4) and / or (5). By selectively using those having three or more sulfo groups, the water solubility of the aromatic compound can be improved, and as a result, the precipitation of the aromatic compound on the surface of the recording medium can be prevented / suppressed. I think that the effect to do is expressed. As a result, it is possible to improve the gas resistance, particularly ozone resistance of the printed matter without any trouble.

In the present embodiment, an aromatic compound having three or more sulfo groups represented by the general formula (4) and / or (5) and / or a salt thereof is used in combination with a phthalocyanine cyan dye, Suppresses the discoloration of the image derived from ozone gas without causing greening or blackening due to NO _x gas, and without causing precipitation of additives, and dramatically improves the discoloration resistance of the image. It is a thing.

  Further, in the present embodiment, the cyan ink composition is of course any ink composition that contains at least one aromatic compound and / or salt thereof having water, a phthalocyanine-based cyan dye, and three or more sulfo groups. For example, even an ink composition having a color different from cyan, such as a black ink composition, can effectively prevent the discoloration color seen when printing. In order to produce these various ink compositions, they can be used in combination with other conventionally known dyes.

  As the aromatic compound having three or more sulfo groups and / or a salt thereof represented by the general formula (4) and / or (5), an aromatic compound having at least three sulfo groups in the molecular structure and / or Any salt may be used, but in particular, naphthalene-1,3,5-trisulfonic acid, naphthalene-1,3,6-trisulfonic acid, naphthalene-1,3,7-trisulfonic acid, naphthalene At least one selected from the group consisting of -1,4,6-trisulfonic acid, naphthalene-1,4,7-trisulfonic acid and salts thereof is ozone resistance of the resulting image and additive precipitation It is preferable in terms of improvement in suppression. Furthermore, the lithium salt of these aromatic sulfonic acid compounds is more preferable because it works effectively in terms of suppressing bronzing of printed images.

  The content of the aromatic compound having a sulfo group and / or a salt thereof is appropriately determined depending on the type of the aromatic compound having a sulfo group and / or a salt thereof, the type of the dye, the type of the solvent component, and the like. Preferably it is 0.1 to 10 weight% with respect to the total weight of an ink composition, More preferably, it is the range of 0.5 to 10 weight%.

  In the ink composition of the present embodiment, the content ratio (the former: the latter) of the phthalocyanine cyan dye and the aromatic compound having a sulfo group and / or a salt thereof effectively improves the gas resistance and From the viewpoint of ensuring the reliability of the ink, it is preferably in the range of 1: 0.1 to 1:10, particularly 1: 0.2 to 1: 5.

  Regarding the pH in the ink composition of the present embodiment, other additives such as a humectant, a nitrogen-containing organic solvent, a nonionic surfactant, a penetration accelerator, and their contents, and a method for preparing the ink composition, The description is the same as that of the ink composition of the first embodiment described above, and the description is appropriately applied to this embodiment.

  The present invention can also provide an ink cartridge including at least the ink composition described above. According to the ink cartridge of the present invention, it is possible to improve the indoor storage stability (gas resistance) of the formed image without causing additive precipitation or bronzing, and effectively prevent early discoloration of the image. It is possible to facilitate handling such as transportation of ink.

  Next, the recording method of the present invention using the above-described ink composition will be described. In the recording method of the present invention, an ink jet recording method in which an ink composition is ejected as droplets from fine holes and the droplets are attached to a recording medium for recording can be used particularly preferably. Needless to say, it can also be used for applications such as pen plotters.

  As the ink jet recording method, any of the conventionally known methods can be used, and in particular, a method of ejecting droplets using vibration of a piezoelectric element (using an ink jet head that forms ink droplets by mechanical deformation of an electrostrictive element). Recording method) and a method using thermal energy, it is possible to perform excellent image recording.

  In addition, the recorded matter of the present invention was recorded using the above-described ink composition, and was excellent in the indoor storage stability (gas resistance) of the formed image without additive precipitation or bronzing. Quality is maintained for a long time.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these examples.

(A desirable first aspect of the invention)
[Examples 1-4, 8-10, Comparative Examples 1-4 and Reference Examples 1-3 ]
Examples 1 to 10 (However, Examples 5 to 7 are not included. The same applies hereinafter), Comparative Examples 1 to 4 and Reference Examples 1 to 3 were mixed and dissolved in the components shown in Table 1. Each ink composition was prepared by performing pressure filtration with a membrane filter having a pore diameter of 1 μm.

なお、表１中に示すインク組成物の各成分はインク組成物全量に対する各成分の重量％を示し、残量は水である。

In addition, each component of the ink composition shown in Table 1 indicates weight% of each component with respect to the total amount of the ink composition, and the remaining amount is water.

  The ink compositions described in Examples 1 to 10 and Comparative Examples 1 to 4 are filled into a dedicated cartridge (Cyan chamber) using an inkjet printer EM930C (manufactured by Seiko Epson Corporation), and used exclusively for inkjet. Printing was performed on a recording medium (PM photo paper: manufactured by Seiko Epson Corporation), and the following evaluations were performed.

≪Ozone resistance test≫
Using the above cartridge, printed matter obtained by performing printing while adjusting the applied duty so that the OD (Optical Density) is in the range of 0.9 to 1.1 is obtained as an ozone weather meter OMS-H type ( The product was exposed for a predetermined time (6, 9, 12 hours) under the conditions of 24 ° C., relative humidity 60% RH, and ozone concentration 10 ppm.

  After the exposure, the OD of each printed matter was measured using a densitometer (Spectrolino: manufactured by Gretag), the optical density residual ratio (ROD) was determined by the following formula, and evaluated according to the following criteria.

ROD (%) = (D / D0) × 100
D: OD after exposure test
D0: OD before exposure test
(However, the measurement conditions are Filter: Red, Light source: D50, Viewing angle: 2 degrees)

[Criteria]
Evaluation A: ROD is 90% or more Evaluation B: ROD is 80% or more and less than 90% Evaluation C: ROD is 70% or more and less than 80% Evaluation D: ROD is less than 70%

<< Additive resistance test >>
The printed matter obtained by printing with an applied duty of 100% was left in an environment of 25 ° C. and 50% RH for 2 weeks, 4 weeks, and 6 weeks.
After standing, the printed matter was visually observed to see if precipitates were observed on the application surface.

[Criteria]
Evaluation A: No precipitate.
Evaluation B: Although there is a portion that looks slightly whitish, it is not clearly recognized as a precipitate. There is no problem in practical use.
Evaluation C: The applied surface becomes whitish, but precipitates cannot be recognized. Acceptable level.
Evaluation D: The application surface is clearly white and the occurrence of precipitates can be easily confirmed.

≪Bronze resistance≫
The printed matter obtained by adjusting the applied duty so as to obtain a driving amount of 1.5 to 2.2 mg per inch square meter was measured using a gloss meter (PG-1M: manufactured by Nippon Denshoku Industries Co., Ltd.). (Measurement angle 60 °), glossiness was determined. Printing was performed in two environments of 20 ° C. and 55% RH and 32 ° C. and 75% RH.
The glossiness obtained and the value obtained from the following equation were used as the bronze criteria.
Glossiness (printed material)-Glossiness (recording medium)

[Criteria]
Evaluation A: Less than 15 Evaluation B: 15 or more and less than 35 Evaluation C: 35 or more and less than 55 Evaluation D: 55 or more

≪Clogging resistance test≫
The ink was filled into an inkjet printer EM-930C (manufactured by Seiko Epson Corporation) and then continuously printed for 10 minutes. After confirming that the ink was discharged from the nozzle, printing was stopped. This was left for 2 weeks in an environment of 40 ° C. and 25% RH without capping the head. After leaving, nozzle cleaning operation was performed, and then printing was performed. The ink clogging characteristics were evaluated by the number of cleaning operations until there was no defective printing such as blurring or missing, and printing equivalent to the initial printing became possible.

[Criteria]
Evaluation A: When printing equivalent to the initial value is obtained by 1 to 5 cleaning operations Evaluation B: When printing equivalent to the initial value is obtained by 6 to 10 cleaning operations Evaluation C: Cleaning operation 11 to 15 times When the same print as the initial print is obtained with Evaluation D: Print equivalent to the initial print is not possible even after 16 or more cleaning operations

  The obtained evaluation results are shown in Table 2.

(A desirable second aspect of the invention)
[Examples 12-15, 17, 18 , Comparative Examples 5-7 and Reference Examples 4, 5 ]
Examples 11 to 18 (However, Examples 11 and 16 are not included. The same applies hereinafter), Comparative Examples 5 to 7 and Reference Examples 4 and 5 were mixed and dissolved at the blending ratios shown in Table 3. Each ink composition was prepared by performing pressure filtration with a membrane filter having a pore diameter of 1 μm.

なお、表３中に示すインク組成物の各成分はインク組成物全量に対する各成分の重量％を示し、残量は水である。

In addition, each component of the ink composition shown in Table 3 indicates the weight% of each component with respect to the total amount of the ink composition, and the remaining amount is water.

  The ink compositions described in Examples 1 to 18 and Comparative Examples 5 to 7 were printed by the same method as in the first preferred embodiment, and the following evaluations were made.

≪Ozone resistance test≫
Except that the ozone concentration was 2 ppm, ozone exposure was performed in the same manner as in the first preferred embodiment.

After the exposure, the OD of each printed matter was measured using a densitometer (Spectrolino: manufactured by Gretag) to determine the residual optical density (ROD), and evaluated according to the following criteria.
[Criteria]
Evaluation A: ROD is 90% or more Evaluation B: ROD is 80% or more and less than 90% Evaluation C: ROD is 70% or more and less than 80% Evaluation D: ROD is less than 70%

<< Additive resistance test >>
With respect to the ink compositions of Examples 1 to 18 and Comparative Examples 5 to 7, an additive precipitation resistance test was performed in the same manner as in the first preferred embodiment. And it evaluated by the same criteria.

≪Bronze resistance≫
The ink compositions of Examples 1 to 18 and Comparative Examples 5 to 7 were subjected to a bronze resistance test in the same manner as in the first preferred embodiment. And it evaluated by the same criteria.

≪Clogging resistance test≫
About the ink composition of Examples 1-18 and Comparative Examples 5-7, the clogging-proof test was done by the method similar to the desirable 1st aspect. And it evaluated by the same criteria.

  The obtained evaluation results are shown in Table 4.

  The present invention is an ink composition using a phthalocyanine-based cyan dye, which can improve indoor storage stability (gas resistance) of a formed image without causing problems such as precipitation of additives and generation of bronze, The present invention has industrial applicability as an ink composition that can effectively prevent premature discoloration of an image, and an ink cartridge, an ink jet recording method, and a recorded matter using the ink composition.

It is a figure which shows the spectral characteristic (absorption wavelength) of the dye (CI direct blue 199) (* 1) contained in the ink composition of the desirable 1st aspect which concerns on this invention. It is a figure which shows the spectral characteristic (absorption wavelength) of the dye (CI direct blue 86) (* 4) contained in the ink composition of the desirable 2nd aspect which concerns on this invention.

Claims (22)

An ink composition comprising at least water, a phthalocyanine cyan dye, and a lithium salt of an aromatic compound having a sulfo group represented by the following general formula (2) .

The ink composition according to claim 1, wherein the phthalocyanine cyan dye is a copper phthalocyanine dye represented by the following formula (3).

  The copper phthalocyanine dye is C.I. I. The ink composition according to claim 2, which is Direct Blue 86, 87, and / or 199.   The ink composition according to claim 1, wherein the lithium salt of the aromatic compound having a sulfo group has two or more sulfo groups.   The ink composition according to any one of claims 1 to 4, wherein the phthalocyanine cyan dye has a group containing a lithium ion as a counter ion. Lithium salt of an aromatic compound having a sulfo group, Na Futaren 1,5-disulfonic acid, naphthalene-1,6-disulfonic acid, naphthalene-2,6-disulfonic acid, naphthalene-2,7-disulfonic acid and The ink composition according to claim 4, wherein the ink composition is at least one selected from the group consisting of lithium salts of naphthalene-1,3,6-trisulfonic acid.   The ink composition according to any one of claims 1 to 6, comprising 0.1 to 10% by weight of the lithium salt of the aromatic compound having a sulfo group based on the total amount of the ink composition.   The content ratio of the said phthalocyanine series cyan dye and the lithium salt of the aromatic compound which has the said sulfo group exists in the range of 1: 0.1-1: 10 in any one of Claims 1-7. Ink composition. The phthalocyanine cyan dye is a dye having a maximum absorption peak absorption spectrum in the wavelength 590~650nm in the visible range (400 to 800 nm), the ink composition according to any one of claims 1-8. The phthalocyanine cyan dye is a dye having a maximum absorption peak absorption spectrum in the wavelength 590~615nm in the visible range (400 to 800 nm), the ink composition according to any one of claims 1-9. The phthalocyanine cyan dye is a dye having a maximum absorption peak absorption spectrum in the wavelength 590~605nm in the visible range (400 to 800 nm), the ink composition according to any one of claims 1-10. The ink composition according to any one of claims 1 to 11 , further comprising a nonionic surfactant. The ink composition according to claim 12 , wherein the nonionic surfactant is an acetylene glycol surfactant. The ink composition according to claim 12 or 13 , comprising 0.1 to 5% by weight of the nonionic surfactant based on the total amount of the ink composition. The ink composition according to any one of claims 1 to 14 , further comprising a penetration enhancer. The ink composition according to claim 15 , wherein the penetration enhancer is a glycol ether. PH of the ink composition at 20 ° C. is a 8.0 to 10.5, the ink composition according to any one of claims 1-16. Used in the ink jet recording method, an ink composition according to any one of claims 1 to 17. The ink composition according to claim 18 , wherein the ink jet recording method is a recording method using an ink jet head that forms ink droplets by mechanical deformation of an electrostrictive element. Ink cartridge, wherein at least comprising the ink composition according to any one of claims 1 to 19. An ink jet recording method for performing recording by discharging droplets of an ink composition and attaching the droplets to a recording medium, wherein the ink composition according to any one of claims 1 to 19 is used as the ink composition. An ink jet recording method comprising: Recorded material characterized by being recorded by using the ink composition according to any one of claims 1 to 19.

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