JP5142487B2 - Ink jet ink, ink jet ink manufacturing method, ink jet recording method, ink cartridge, and yellow ink - Google Patents

Description

  The present invention relates to an inkjet ink, a method for manufacturing an inkjet ink, an inkjet recording method, an ink cartridge, and a yellow ink.

  The ink jet recording method is a recording method in which an ink is applied to a recording medium such as plain paper or glossy media to form an image, and is rapidly spreading due to its low cost and high recording speed. Further, in addition to the progress of higher image quality of recorded materials, with the rapid spread of digital cameras, it has become widespread as a method for outputting an image equivalent to a silver salt photograph. In such an environment, in order to provide a recorded matter that meets the needs of the times, not only the characteristics of the ink used in the ink jet recording method but also the characteristics of the color material have been devised.

  It is expected that the color material used for the yellow ink for inkjet is less likely to cause migration of the color material, that is, less likely to cause a change in color tone or a fading. As a dye having such characteristics, C.I. I. Direct Yellow 86 and C.I. I. There are proposals regarding the use of Direct Yellow 173 (see Patent Documents 1 and 2).

  In addition, pigments that are inferior in color developability compared to dyes but are excellent in image water resistance and the like have been used as ink coloring materials. Among them, C.I. I. The color developability of Pigment Yellow 74 is superior to pigments having other yellow hues. For this reason, C.I. I. There are many proposals regarding the use of Pigment Yellow 74 (see Patent Documents 3 and 4). Furthermore, for the purpose of improving the storage stability and color developability of ink, there is a proposal for using a dye and a pigment together as a color material (see Patent Document 5).

Japanese Patent Laid-Open No. 2-233781 JP-A-4-233975 JP-A-11-199811 JP 2000-281952 A Japanese Patent Publication No. 60-45667

  However, with the improvement of the technology related to ink jet, in recent years, it has been required to output a recorded matter at a higher level than the related art with respect to the image quality of an image obtained by the ink jet recording method. In particular, the recorded material used in the office is required to be a recorded material that has high color developability as recorded by a laser printer that uses powder toner, and further has suppressed bleeding between colors (bleeding). Has been.

  For example, depending on the user, when forming an image at a high speed using the above-mentioned dye as a color material, depending on the recording environment and the type of recording medium, the obtained recorded matter may not be satisfactory I found out that That is, when an image is formed with other ink (especially black ink) adjacent to an image formed with yellow ink, the color may spread at the boundary of different color areas or the ink may be mixed unevenly. As a result, a phenomenon in which the quality of the image is degraded may occur. On the other hand, when a pigment is used as a coloring material for the purpose of obtaining fastness such as light resistance and water resistance in an image formed on plain paper, the following problems may occur. That is, for example, C.I. I. Even when CI Pigment Yellow 74 is used, the color developability of the image, in particular, the saturation of the red image formed with the yellow ink and the magenta ink may not be sufficiently obtained. Accordingly, the present inventors have recognized that it is important to provide an image that can suppress bleeding as compared with conventional ink-jet inks and that is also excellent in color developability.

  In view of the above, the first problem to be solved by the present invention is to provide a novel ink-jet ink that can suppress bleeding and provide an image with excellent color developability. More preferably, for example, when an image is formed with yellow ink adjacent to an image formed with black ink, a novel ink for ink jet which gives an image with suppressed bleeding is provided. In addition, the second problem to be solved by the present invention is a method for producing an ink jet ink which can suppress bleeding and give an image excellent in color developability by means which are economical and preferable from the viewpoint of environmental protection. Is to provide. Furthermore, the third problem to be solved by the present invention is to provide an ink jet recording method and an ink cartridge using an ink for ink jet which gives an image in which bleeding is suppressed and color development is excellent.

As a result of intensive studies to solve the above-described problems, the present inventors have arrived at the present invention. That is, the means for solving the first problem of the present invention is an ink-jet ink containing water, a coloring material, and a water-soluble organic solvent, wherein the coloring material is C.I. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132, and C.I. I. One or more dyes selected from the group consisting of Direct Yellow 59, and C.I. I. A Pigment Yellow 74, surface tension of the ink is at 34.0mN / m or more, the water-soluble organic solvent, the C. I. A poor solvent for CI Pigment Yellow 74 , and the C.I. I. An inkjet ink, wherein a ratio (B / A) of the content B (mass%) of the poor solvent to a content A (mass%) of Pigment Yellow 74 is 0.75 or more and 4 or less. is there.

Another means for solving the first problem is a yellow ink used together with a black ink containing water, carbon black, and a water-soluble organic solvent, wherein the water, the color material, and the water-soluble An organic solvent is contained, and C.I. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132 and C.I. I. One or more dyes selected from the group consisting of Direct Yellow 59, and C.I. I. Pigment Yellow 74, the surface tension of the ink is 34.0 mN / m or more, and the water-soluble organic solvent is C.I. I. It includes a poor solvent for Pigment Yellow 74, above SL in the ink, the C. I. A ratio (B / A) of the content B (mass%) of the poor solvent to a content A (mass%) of Pigment Yellow 74 is 0.75 or more and 4 or less. .

  A means for solving the second problem is a method for producing an ink jet ink for obtaining the ink jet ink having the above-described configuration, comprising C.I. I. Pigment yellow 74, and the C.I. I. An ink cartridge containing a poor solvent for Pigment Yellow 74 and containing ink having a surface tension of 34.0 mN / m or more is used as a coloring material. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132 and C.I. I. An ink-jet ink production method comprising a step of injecting an ink-jet ink containing one or more dyes selected from the group consisting of direct yellow 59.

  A means for solving the third problem is an inkjet recording method using the inkjet ink, yellow ink, or inkjet ink obtained by the inkjet ink manufacturing method, and any of the above An ink cartridge that accommodates ink for inkjet.

  According to the present invention, it is possible to provide an inkjet ink and a yellow ink that can suppress bleeding and can provide an image with improved color developability of the image, particularly, red saturation. In addition, by reusing the ink jet ink remaining in the ink cartridge, it is possible to produce an ink jet ink manufacturing method that is economical and preferable from the viewpoint of environmental protection. can do. Furthermore, it is possible to provide an ink jet recording method and an ink cartridge that can suppress bleeding and can provide an image with improved color developability of the image, in particular, red saturation.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments. Hereinafter, in the present invention, the inkjet ink is referred to as “ink”, and C.I. I. Pigment Yellow 74 may be referred to as “yellow pigment”. The ink according to the present invention is an ink having a yellow hue, and needs to contain a specific dye and a specific yellow pigment as a coloring material. Examples of the dye include C.I. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132 and C.I. I. One or more selected from the group consisting of direct yellow 59 is used. The yellow pigment includes C.I. I. Pigment Yellow 74 is used. Further, the ink according to the present invention may be a C.I. I. It is necessary to contain a poor solvent for Pigment Yellow 74, and the surface tension of the ink should be 34.0 mN / m or more.

  In general, an image formed using an ink containing a pigment as a coloring material is superior to an image formed using an ink containing a dye as a coloring material, but has fastness such as light resistance and water resistance. There are cases where sufficient sex cannot be obtained. For this reason, in order to make both fastness and color developability excellent as in the invention described in Patent Document 5, the use of dyes and pigments as coloring materials has been performed so far. . However, as a result of studies by the present inventors, the following has been found. That is, simply using a dye and a pigment together has a great effect in terms of obtaining the excellent color developability that is the object of the present invention and suppressing bleeding compared to a conventional ink containing a dye or pigment as a colorant. It turned out that it does not reach the level that can be obtained.

  Thus, as a result of further studies by the present inventors, it has been found that the effect of the present invention described above can be remarkably obtained by including a poor solvent for the pigment in the ink. In particular, in the case of an ink having a yellow hue, by controlling the type of dye and pigment in the ink and the ratio of their contents to have a specific relationship, bleeding is suppressed and color developability, particularly the saturation of a red image. It was found that the effect of making the material excellent was obtained more remarkably.

  Although the reason why the effect of forming an image with excellent color developability is remarkably obtained by using the ink according to the present invention is not clear, the present inventors explain the reason why excellent color developability is obtained as follows. I guess. By containing a poor solvent for the yellow pigment in the ink, the yellow pigment agglomerates with evaporation and penetration of water in the ink after the ink is applied to the recording medium. As a result, the yellow pigment aggregates formed near the surface of the recording medium suppress the penetration of the dye in the depth direction of the recording medium. Further, it is presumed that the dyeing rate of the image is improved by dyeing the gaps between the aggregates of the yellow pigment existing near the surface of the recording medium.

  The reason why bleeding can be suppressed by using the ink according to the present invention is not clear. However, the present inventors presume the reason why bleeding can be suppressed as follows. When the ink according to the present invention is applied to the recording medium, the dye in the ink spreads along the fiber in the same manner as the conventional ink after the ink adheres to the recording medium. On the other hand, the yellow pigment in the ink generates agglomerates because the ratio of the yellow pigment and the poor solvent in the ink increases rapidly with the evaporation of water immediately after the ink adheres to the recording medium (FIG. 3). (See (a) and (b)). The aggregates are rapidly generated as the ratio of the poor solvent in the ink is increased. Therefore, the aggregates are generated as if a bank of a yellow pigment is formed at the outer edge portion of the dot, not at the center portion of the dot. As a result, the spread of the dye in the lateral direction can be suppressed (see FIG. 3C). Due to such a mechanism, even when other ink is applied so as to be adjacent to the dot (image) formed by the ink according to the present invention, it is compared with a conventional ink that only contains both a dye and a yellow pigment as a coloring material. We believe that bleeding can be suppressed.

  At this time, it is considered that bleeding can be more effectively suppressed by adopting the following configuration. That is, the yellow ink of the present invention is used in combination with the black ink, carbon black is used as the color material of the black ink, and the ink according to the present invention described above is used as the yellow ink. At this time, it is preferable to use a black ink containing a poor solvent for carbon black as a coloring material. Furthermore, C.I. in yellow ink used with such black ink. I. It is preferable that the poor solvent for Pigment Yellow 74 is a poor solvent for carbon black in the black ink because bleeding can be suppressed particularly effectively. The reason why bleeding can be suppressed particularly effectively with the above-described configuration is considered as follows. That is, when the color materials come into contact with each other at a location where they penetrate on the recording medium or inside the recording medium (in the depth direction), the color materials are substantially formed by the rapid formation of aggregates. I guess it is because they do not mix. In particular, in the black ink having the above-described configuration, the carbon black is a self-dispersing carbon black in which at least one ionic group is bonded to the surface of the carbon black particles directly or through another atomic group. preferable. In addition, it is particularly preferable that the poor solvent contained in the yellow ink and the black ink exhibits the maximum Ka value among the Ka values of the water-soluble organic solvents contained in these inks.

Here, the Ka value obtained by the Bristow method will be described. This value is used as a measure for the penetrability of the liquid into the recording medium. Hereinafter, the ink will be described as an example. When the ink permeability is expressed as an ink amount V per 1 m ² , the ink penetration amount V (mL / m ² = μm) after a predetermined time t has elapsed since the ink was ejected is It is shown by Bristow's formula (formula (1)) shown below.
V = V _r + Ka (t−t _w ) ^1/2 formula (1)

Most of the ink immediately after being applied to the recording medium is absorbed by the uneven portion (rough portion of the recording medium surface) on the surface of the recording medium and hardly penetrates into the inside (depth direction) of the recording medium. . The time during this period is the contact time (t _w ), and the amount of ink absorbed in the uneven portion of the recording medium at the contact time is V _r . When the contact time is exceeded after the ink is applied to the recording medium, the time exceeding the contact time, that is, the ink proportional to the 1/2 power of (t−t _w ) Penetrating in the vertical direction) and the amount of penetration increases. Ka is a proportional coefficient for this increase, and is a value corresponding to the penetration rate.

  The Ka value described above can be measured using a liquid dynamic permeability test apparatus (for example, trade name: dynamic permeability test apparatus S; manufactured by Toyo Seiki Seisakusho Co., Ltd.) by the Bristow method. The Ka value according to the Bristow method in the present invention is a value measured using plain paper as a recording medium. Specific examples of plain paper include, for example, copying machines using an electrophotographic system, page printers (laser beam printers), PB paper for printers using an inkjet recording system (manufactured by Canon), and copying using an electrophotographic system. PPC paper for machine etc. is mentioned. The measurement environment is assumed to be a normal office environment such as a temperature of 20 ° C. to 25 ° C. and a humidity of 40% to 60%.

  As described above, by using the ink according to the present invention, the effect of improving the saturation of the red image is remarkably obtained, but the reason is not clear. The present inventors presume the reason why excellent red image saturation is obtained as follows.

  When an image is formed using a yellow pigment as a color material, the color developability of the image tends to be inferior compared to the case where an image is formed using a dye as a color material. In contrast, since the ink according to the present invention contains a poor solvent for the yellow pigment (CI Pigment Yellow 74), the ink of the recording medium is better than the ink containing the conventional yellow pigment. Aggregates of yellow pigment can be formed in the vicinity of the surface. The phenomenon that the yellow pigment aggregates closer to the surface of the recording medium than the ink containing the conventional yellow pigment is the same as the mechanism described above. That is, with the evaporation of water immediately after the ink adheres to the recording medium, the ratio of the yellow pigment and the poor solvent in the ink increases rapidly, and aggregates are generated. The aggregates are rapidly generated as the ratio of the poor solvent in the ink is increased. Therefore, the aggregates are generated as if a bank of a yellow pigment is formed at the outer edge portion of the dot, not at the center portion of the dot. As a result, aggregates are generated near the surface of the recording medium before the color material spreads in the lateral direction (see FIGS. 3D and 3E). The ink of the present invention contains a specific yellow dye together with a yellow pigment. When the pigment ink having a structure capable of causing such a phenomenon further contains a dye as a coloring material, an aggregate of yellow pigments Dye is dyed in the gap. For this reason, the dyeing rate is improved in the vicinity of the surface of the recording medium (see FIG. 3F). The present inventors presume that the saturation of the red image is improved by the above-described mechanism when the ink of the present invention is used.

  According to the study by the present inventors, in order to obtain the above three effects of excellent color developability, suppression of bleeding, and improvement of the saturation of the red image at the same time, the penetration speed of the ink into the recording medium is set. It needs to be kept low to some extent. More specifically, the ink of the present invention needs to have a surface tension of 34.0 mN / m or more at 25 ° C. Furthermore, it is preferable to set it as 38.0 mN / m or more in 25 degreeC. When the surface tension of the ink is less than 34.0 mN / m, the penetration speed of the ink into the recording medium is larger than the aggregation speed of the yellow pigment. For this reason, even if bleeding can be suppressed, sufficiently good color developability may not be obtained. The surface tension of the ink according to the present invention is preferably 41.0 mN / m or less. When the surface tension of the ink exceeds 41.0 mN / m, the fixing property of the ink on the recording medium may not be sufficiently obtained, or bleeding may not be sufficiently suppressed.

  A conventional ink set having the effect of suppressing bleeding is configured such that the penetration speed of each ink contained in the ink set into the recording medium is increased so that each ink does not mix colors on the recording medium. In particular, the color ink is often a so-called penetrating ink in order to suppress bleeding between a plurality of color inks. For example, even if the color material to be used is an ink that satisfies the configuration of the color material defined in the present invention as in the embodiment of Japanese Patent Laid-Open No. 2003-20428, it is one of the effects of the present invention. Some excellent color developability cannot be obtained. This is a so-called penetrating ink that uses a combination of a dye and a pigment as the coloring material, but the ink further contains a large amount of a water-soluble organic solvent such as alkanediol and a surfactant. Because it is.

  One of the points of the present invention is that, unlike conventional so-called penetrating inks that suppress bleeding as described above, bleeding can be suppressed even if the permeability is suppressed to some extent. In the present invention, the temperature for measuring the surface tension was 25 ° C., and a Kyowa CBVP-2 surface tension meter (manufactured by Kyowa Kagaku) was used for the measurement of the surface tension.

  Furthermore, the more preferable form of this invention is demonstrated. First, in the ink according to the present invention, C.I. I. Pigment Yellow 74 content is A (mass%), C.I. I. When the content of the poor solvent for Pigment Yellow 74 is B (mass%), the ratio of B to A (B / A) is 0.75 or more and 4 or less. Furthermore, the ratio of B to A (B / A) is preferably 1 or more and 4 or less. The values A and B indicate the content (% by mass) based on the total mass of the ink. By setting the ratio of B to A (B / A) to be 0.75 or more, a larger yellow pigment aggregate can be formed in the vicinity of the surface of the recording medium. For this reason, when the content (% by mass) of the yellow pigment in the ink is 4% by mass or more, particularly excellent color developability can be obtained. Furthermore, by setting the ratio of B to A (B / A) to 1 or more, even when the yellow pigment content (% by mass) in the ink is less than 4% by mass, a large yellow pigment is formed near the surface of the recording medium. It becomes easy to form an aggregate. For this reason, bleeding when forming an image on plain paper can be easily suppressed, and excellent color developability can be easily obtained. Further, by setting the ratio of B to A (B / A) to 4 or less, an ink having excellent storage stability can be obtained even when the ink is stored for a long time. Specifically, the change rate of the average particle diameter of the yellow pigment in the ink is small, and it is possible to obtain effects such as that the ink does not substantially increase in viscosity and that no gel-like precipitate is generated in the ink. .

  In order to obtain excellent color developability when the ink according to the present invention is applied to a recording medium, the following configuration is preferable. C. in the ink of the present invention. I. B (mass%), C.I. I. When the content of the good solvent for Pigment Yellow 74 is C (mass%), C: B is preferably 10: 5 to 10:30. That is, when the good solvent content C is 10, the poor solvent content B is preferably 5 or more and 30 or less (that is, C / B is 0.3 or more and 2 or less). That is, by setting the ratio of the content of the poor solvent and the good solvent in the ink within the above range, agglomerates of yellow pigment can be formed in the vicinity of the surface of the recording medium. Can be obtained. In addition, the definition of the poor solvent with respect to the pigment in this invention and a good solvent, and the method of the selection are mentioned later.

<Coloring material content>
In addition, when the content of the dye in the ink is too large, there is a possibility that the water resistance of the image is lowered as compared with the ink containing the conventional pigment. For this reason, it is preferable to determine the content of the dye as appropriate, particularly when the ink is used with emphasis on image fastness. The ratio of the yellow pigment content A (mass%) and the dye content D (mass%) in the ink of the present invention is preferably as follows. In addition, content A and D show content (mass%) on the basis of the total mass of ink, respectively. When the content of the dye in the ink is larger than the content of the yellow pigment, the content A (mass%) of the yellow pigment in the ink is based on the content D (mass%) of the dye in the ink. That is, it is preferable that the value of A / D × 100% is 7% or more and 34% or less. By setting the ratio of the content of the yellow pigment and the dye in the ink to 7% or more, a sufficient amount of aggregates are formed to suppress the lateral spread of the dye in the recording medium. Bleeding can be suppressed more effectively. In addition, by setting the ratio of the yellow pigment and dye content in the ink to 34% or less, the degree of image degradation caused by the difference in light resistance between the dye-added portion and the yellow pigment-added portion of the recording medium There is almost no difference. For this reason, when the image is stored for a long period of time, it is possible to obtain an image in which the color balance between the portion to which the dye is applied and the portion to which the yellow pigment is applied is uniform.

  When the yellow pigment content in the ink is higher than the dye content, the dye content D (% by mass) in the ink is equal to the yellow pigment content A (% by mass) in the ink. On the other hand, it is preferable that the value of D / A × 100% is 5% or more and 25% or less. By setting the ratio of the content of the yellow pigment and the dye in the ink to 5% or more, excellent color developability can be obtained. Also, by setting the ratio of the yellow pigment and dye content in the ink to 25% or less, it is almost as high as the image produced by the difference in light resistance between the dye-added portion and the yellow pigment-added portion of the recording medium. The difference disappears. For this reason, when the image is stored for a long period of time, it is possible to obtain an image in which the color balance of the portion to which the dye is applied and the portion to which the yellow pigment is applied in the recording medium is uniform.

  Specifically, the yellow pigment content and the dye content in the ink according to the present invention are preferably as follows. First, in a configuration in which the content of the dye in the ink is greater than the content of the yellow pigment, the content (% by mass) of the yellow pigment in the ink is set to 0.2% by mass or more based on the total mass of the ink. Is preferably 0.6% by mass or more and 2% by mass or less. When the content of the dye in the ink is higher than the content of the yellow pigment, if the content of the yellow pigment is less than 0.2% by mass, the effect of suppressing excellent color developability and bleeding cannot be obtained. There is a case. This is because when plain paper is used as the recording medium, the effect of suppressing the phenomenon in which the dye spreads in the lateral direction cannot be obtained sufficiently. Further, in a configuration in which the content of the dye in the ink is greater than the content of the yellow pigment, the content (% by mass) of the dye in the ink is 3.0% by mass or more and 3.4% or more based on the total mass of the ink. It is preferable to set it as mass% or less. When the content of the dye in the ink is greater than the content of the yellow pigment, if the content of the dye is less than 3.0% by mass, excellent color developability may not be obtained. This is because if the content exceeds 3.4% by mass, excellent fastness may not be obtained.

  On the other hand, in a configuration in which the yellow pigment content in the ink is higher than the dye content, the yellow pigment content (% by mass) in the ink is 4.0% by mass or more based on the total mass of the ink. It is preferable to make it 0.0 mass% or less. When the yellow pigment content in the ink is greater than the dye content, excellent color developability can be obtained by setting the yellow pigment content to 4.0% by mass or more. When the yellow pigment content in the ink is higher than the dye content, the dye content (% by mass) in the ink is 0.2% by mass or more based on the total mass of the ink. It is preferable to set it to 0.6 mass% or more and 1.1 mass% or less. When the yellow pigment content in the ink is greater than the dye content, by setting the dye content to 0.6% by mass or more, the aggregate of yellow pigments in which the dye is present near the surface of the recording medium Can be dyed, and excellent color developability can be obtained.

<Definition of poor solvent and good solvent>
The ink according to the present invention includes C.I. I. Pigment Yellow 74 is contained in a state dispersed in an aqueous medium obtained by mixing water and a water-soluble organic solvent. C. above. I. The following can be used for the pigment yellow 74. For example, a self-dispersing pigment in which at least one ionic group is bonded to the surface of the pigment particle directly or through another atomic group, a resin dispersion type in which it is dispersed in an aqueous medium by a dispersant, a surfactant or the like And pigments. In the present invention, C.I. present in the ink in the state as described above. I. The water-soluble organic solvent that can keep the dispersion state of Pigment Yellow 74 dispersion stable is defined as a good solvent, and the water-soluble organic solvent that cannot keep the dispersion state stable is defined as a poor solvent.

More specifically, C.I. I. It is determined whether the water-soluble organic solvent used is a poor solvent or a good solvent for the Pigment Yellow 74 dispersion. First, the following water-soluble organic solvent to be determined, C.I. I. Two types of dispersions are prepared: a dispersion X of Pigment Yellow 74 dispersion and an aqueous dispersion Y of the pigment dispersion.
Dispersion X: 50% by mass of a water-soluble organic solvent as a determination target; I. Pigment yellow 74, or the C.I. I. A dispersion having a composition in which the total amount of pigment yellow 74 and substances contributing to dispersion thereof is 5% by mass and water is 45% by mass.
Aqueous dispersion Y: C.I. I. Pigment yellow 74, or the C.I. I. An aqueous dispersion having a composition in which the total amount of pigment yellow 74 and substances contributing to dispersion thereof is 5 mass% and water is 95 mass%.

  Next, after the dispersion X was stored at 60 ° C. for 48 hours, C.I. I. The average particle size of Pigment Yellow 74 is measured. Similarly, the C.V. I. The average particle size of Pigment Yellow 74 is measured. And each C. of dispersion X and aqueous dispersion Y is obtained. I. Let the average particle diameter of the pigment yellow 74 be a particle diameter (A) and a particle diameter (B). At this time, when the particle size (A) is larger than the particle size (B), the water-soluble organic solvent is a poor solvent, and the particle size (A) is equal to or smaller than the particle size (B). Determined as solvent.

  In the above, C.I. I. Although it demonstrated as a determination method of the poor solvent and good solvent with respect to the pigment yellow 74 dispersion, even when a pigment is carbon black, determination of a poor solvent and a good solvent can be performed by the method similar to the above. Specific examples of the water-soluble organic solvent which is a poor solvent used in the present invention include polyethylene glycol 1000 (polyethylene glycol having an average molecular weight of 1,000), 2-pyrrolidone, 1,5-pentanediol and the like. Specific examples of the water-soluble organic solvent that is a good solvent include glycerin and ethylene glycol. Of course, the poor solvent and the good solvent that can be used in the present invention are not limited to these.

<Inkjet ink>
Next, each component constituting the ink according to the present invention will be described. [Color material]
The ink according to the present invention is a pigment, such as C.I. I. It is necessary to contain CI Pigment Yellow 74. In the present invention, among the pigments, C.I. I. The reason why Pigment Yellow 74 is used will be described below. The pigment which can suppress the bleeding which is the effect of the present invention described above and can obtain an image excellent in color developability is particularly C.I. I. It is not limited to Pigment Yellow 74. C. I. Pigment Yellow 74 has higher color developability than other pigments having a yellow hue, but has a property that light resistance is as low as that of a dye. For this reason, it is thought that the effect that the discoloration balance at the time of storing a recorded matter for a long time cannot be easily lost can be obtained. Therefore, in the present invention, C.I. I. Pigment Yellow 74 was used.

  Furthermore, the ink according to the present invention has the above-described C.I. I. In addition to Pigment Yellow 74, it is necessary to contain certain dyes. The specific dye is C.I. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132 and C.I. I. One or more dyes selected from the group consisting of Direct Yellow 59. These dyes have properties such as excellent color developability. For this reason, by using these dyes, it is possible to form an image equivalent to a silver salt photograph required for ink-jet inks in recent years.

(C.I. Pigment Yellow 74)
The ink according to the present invention contains C.I. I. Pigment Yellow 74 can be used regardless of the dispersion method. For example, a resin dispersion type pigment (resin dispersion type pigment) dispersed using a dispersant or a surfactant dispersion type pigment dispersed by a surfactant can be used. In addition, a self-dispersing pigment (self-dispersing pigment) that can be dispersed without introducing a ionic group on the surface of the pigment particles and using a dispersant or the like can be used. Furthermore, microcapsule type pigments with improved dispersibility by coating the surface of pigment particles with organic polymers, and organic groups containing polymers on the surface of pigment particles were modified by chemical bonding. Polymer-bonded self-dispersing pigments can be used. Of course, in the present invention, the above-mentioned pigments having different dispersion methods can be used in combination. Hereinafter, the pigment that can be used in the present invention will be described.

[Resin dispersion type pigment]
The ink according to the present invention contains C.I. I. As the pigment yellow 74, as described above, a resin dispersion type pigment can be used. In this case, it is preferable to disperse the hydrophobic pigment in the aqueous medium using a dispersant, a surfactant or the like. The dispersant or surfactant used in this case is not particularly limited, and the following can be used.

As the surfactant, an anionic surfactant or a nonionic surfactant can be used. The following can be used as an anionic surfactant. Specifically, for example, fatty acid salt, alkyl sulfate ester salt, alkylbenzene sulfonate, alkyl naphthalene sulfonate,
Examples thereof include dialkyl sulfosuccinate, alkyl phosphate ester salt, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl sulfate ester salt, and substituted derivatives thereof.
The following can be used for the nonionic surfactant. Specifically, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester,
Examples include sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethyleneoxypropylene block polymer, or substituted derivatives thereof.

The following can be used for a dispersing agent. Specifically, for example, styrene or a derivative thereof, vinyl naphthalene or a derivative thereof, an aliphatic alcohol ester of α, β-ethylenically unsaturated carboxylic acid,
Acrylic acid or derivatives thereof, maleic acid or derivatives thereof, itaconic acid or derivatives thereof, fumaric acid or derivatives thereof,
Block copolymer composed of at least two monomers selected from vinyl acetate, vinyl alcohol, vinyl pyrrolidone, acrylamide, or derivatives thereof (of which at least one is a hydrophilic monomer), random copolymer Coalesced and graft copolymers,
Or these salts etc. are mentioned. Furthermore, a block copolymer and a random copolymer can be used in combination.

[Microcapsule type pigment]
The ink according to the present invention contains C.I. I. As the pigment yellow 74, as described above, a microcapsule type pigment whose dispersibility is improved by coating the surface of pigment particles with organic polymers can be used.

(Self-dispersing pigment)
The ink according to the present invention contains C.I. I. As described above, the pigment yellow 74 may be a self-dispersing pigment that is dispersible without introducing a ionic group on the surface of the pigment particles and using a dispersant or the like. Self-dispersing pigments include those in which an ionic group is bonded directly or via other atomic groups to the surface of pigment particles. For example, ionic groups introduced into the surface of the pigment particles, -COOM, -SO ₃ M, and -PO ₃ H (M) ₂ (where M in the formula, a hydrogen atom, an alkali metal, ammonium or organic ammonium) It is preferable to be one selected from the group consisting of Furthermore, the other atomic group is preferably an alkylene group having 1 to 12 carbon atoms, a substituted or unsubstituted phenylene group, or a substituted or unsubstituted naphthylene group. In addition, the surface oxidation treatment obtained by oxidizing the pigment with sodium hypochlorite or ozone treatment in water, the method of modifying the pigment particle surface by wet oxidation with an oxidizing agent after ozone treatment, etc. A type of self-dispersing pigment can be used.

[Polymer-bonded self-dispersing pigment]
The ink according to the present invention contains C.I. I. As the pigment yellow 74, as described above, a polymer-bonded self-dispersing pigment modified by chemically bonding an organic group containing a polymer to the surface of the pigment particle can be used. A polymer-bonded self-dispersing pigment is obtained by reacting a functional group chemically bonded to the surface of pigment particles directly or through another atomic group with a copolymer of an ionic monomer and a hydrophobic monomer. It is preferable to use what is contained. This can change the copolymerization ratio of the ionic monomer and the hydrophobic monomer, which are the materials of the copolymer used for modifying the surface, as appropriate, and thereby the hydrophilicity of the modified pigment can be arbitrarily set. This is because it can be adjusted. Moreover, since the kind of ionic monomer and hydrophobic monomer and the combination of both can be arbitrarily changed, various characteristics can be imparted to the surface of the pigment particles.

[Aqueous medium]
As described above, the ink according to the present invention is a pigment C.I. I. Pigment Yellow 74, a specific dye, and a poor solvent for the pigment. As the other ink components, any of those used in conventional ink-jet inks can be used. For example, as the aqueous medium for dissolving or dispersing the above-described yellow pigment and dye contained in the ink, any of those listed below can be used as long as it satisfies the inclusion of a poor solvent for the yellow pigment. .

The aqueous medium is preferably water or a mixed medium of water-soluble organic solvent and water. The content (% by mass) of the water-soluble organic solvent in the ink according to the present invention is preferably 3.0% by mass or more and 50.0% by mass or less based on the total mass of the ink. Specifically, for example, the following water-soluble organic solvents can be used. 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 or ketoalcohols such as acetone, methyl ethyl ketone, 2-methyl-2-hydroxypentan-4-one;
Cyclic ethers such as tetrahydrofuran and 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, dithioglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivatives, trimethylolpropane Polyhydric alcohols such as
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;
Heterocycles such as 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylmorpholine;
Sulfur-containing compounds such as dimethyl sulfoxide, urea and urea derivatives.

  The water is preferably deionized water (ion exchange water). The water content (% by mass) in the ink according to the present invention has an appropriate viscosity for stably ejecting the ink, and in order to suppress clogging at the nozzle tip, It is preferable to set it as 50.0 mass% or more and 90.0 mass% or less as a reference | standard.

[Additive]
In addition to the components described above, the ink according to the present invention includes a surfactant, a pH adjuster, a chelating agent, a rust preventive agent, an antiseptic agent, an antifungal agent, an ultraviolet absorber, a viscosity modifier, an antifoaming agent, and Various additives such as a water-soluble polymer may be contained.

Examples of the surfactant include an anionic surfactant, an amphoteric surfactant, a cationic surfactant, and a nonionic surfactant. Specifically, the following can be used for an anionic surfactant, for example.
Alkyl sulfocarboxylate, α-olefin sulfonate, polyoxyethylene alkyl ether acetate, N-acyl amino acid or salt thereof, N-acylmethyl taurate,
Alkyl sulfate polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester, lauryl alcohol sulfate ester,
Alkylphenol phosphate, alkyl phosphate, alkylallylsulfone hydrochloride,
Diethyl sulfosuccinate, diethylhexyl sulfosuccinate dioctyl sulfosuccinate and the like.

Specifically, for example, the following can be used as the cationic surfactant.
Examples include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives. Amphoteric surfactants include lauryldimethylaminoacetic acid betaine,
2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, imidazoline derivatives and the like.

Specific examples of nonionic surfactants include the following.
Polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene lauryl ether,
Ethers such as polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyallylalkyl alkyl ether,
Polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate,
Ester series 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 And the like (for example, acetylenol EH manufactured by Kawaken Fine Chemicals, Surfynol 104, 82, 465, Olphine STG manufactured by Nissin Chemical), and the like.

<Inkjet ink manufacturing method>
The ink according to the present invention may be any ink that satisfies the following structural requirements essential in the present invention. That is, the coloring material is C.I. as a specific dye and pigment. I. It is necessary to contain CI Pigment Yellow 74. The specific dye is C.I. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132 and C.I. I. One or more dyes selected from the group consisting of Direct Yellow 59. In addition, as the water-soluble organic solvent, the C.I. I. It contains a poor solvent for Pigment Yellow 74, and the surface tension of the ink needs to be 34.0 mN / m or more. The ink according to the present invention is not particularly limited as long as it satisfies the above-described constituent requirements, and the production method and the embodiment thereof are not particularly limited.

  The ink-jet ink of the present invention can be produced according to a conventional method using each of the components described above. As described below, the ink-jet ink of the present invention recycles the ink remaining in the ink cartridge, so that the ink according to the present invention is economically and environmentally preferable. It can also be obtained by a manufacturing method.

  Specifically, C.I. I. Pigment yellow 74, and the C.I. I. This is an ink manufacturing method including a step of injecting an ink containing a specific dye into an ink cartridge containing an ink containing a poor solvent for Pigment Yellow 74. The specific dye is C.I. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132 and C.I. I. One or more dyes selected from the group consisting of Direct Yellow 59.

  C. is a pigment having excellent performance by producing an ink by the above-described method. I. The ink cartridge containing the pigment yellow 74 and the poor solvent for the pigment can be reused, and the cost can be reduced. Furthermore, according to the above-described method, it is possible to further obtain an effect of facilitating the filling of the ink into the ink cartridge that once contains the ink and the ink cartridge having the ink storage portion that stores the ink.

<Black ink>
The ink according to the present invention is particularly preferably a yellow ink used together with a black ink containing water, carbon black, and a water-soluble organic solvent. By adopting such a configuration, it is considered that bleeding can be more effectively suppressed. Hereinafter, each component constituting the black ink used in this case will be described.

  Any carbon black contained in the black ink can be used regardless of the dispersion method. That is, C.I. I. Similar to the pigment yellow 74 dispersion method, for example, a resin dispersion type carbon black (resin dispersion type carbon black) dispersed using a dispersant or a surfactant dispersion type carbon black dispersed using a surfactant is used. be able to. Also, self-dispersing carbon black (self-dispersing carbon black) that can be dispersed without introducing a ionic group on the surface of the carbon black particles and using a dispersant or the like can be used. Further, microcapsule type carbon black whose dispersibility is improved by coating the surface of carbon black particles with organic polymers can be used. Furthermore, polymer-bonded self-dispersing carbon black modified by chemically bonding an organic group containing a polymer to the surface of the carbon black particles can be used. Of course, in the present invention, carbon blacks having different dispersion methods mentioned above can be used in combination. Hereinafter, carbon black that can be used in the present invention will be described.

For example, any conventionally known carbon black such as furnace black, lamp black, acetylene black, channel black and the like can be used. Specifically, the following commercially available products can be used.
Raven: 1170, 1190 ULTRA-II, 1200, 1250, 1255, 1500, 2000, 3500, 5000ULTRA, 5250, 5750, 7000 (above Colombia);
Black Pearls L;
Regal: 330R, 400R, 660R;
Mogul L;
Monarch: 700, 800, 880, 900, 1000, 1100, 1300, 1400, 2000;
Vulcan XC-72R (above, manufactured by Cabot).
Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170;
Printex: 35, U, V, 140U, 140V;
Special Black: 4, 4A, 5, 6 (above, manufactured by Degussa).
No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300;
MCF-88, MA600, MA7, MA8, MA100 (above, manufactured by Mitsubishi Chemical).

  Carbon black newly prepared for the present invention can also be used. Magnetic fine particles such as magnetite and ferrite, titanium black, etc. may be used in combination. The carbon black content (% by mass) in the black ink is 0.1% by mass or more and 15.0% by mass or less, and further 1.0% by mass or more and 10.0% by mass or less, based on the total mass of the black ink. It is preferable that

[Aqueous medium]
The aqueous medium used for the black ink is preferably water or a mixed medium of a water-soluble organic solvent and water. And it is preferable that this black ink contains the poor solvent with respect to carbon black demonstrated previously. The carbon black described above includes a dispersion such as a resin dispersion type carbon black and a self-dispersion type carbon black. This is because bleeding can be more effectively suppressed by adopting such a configuration. Furthermore, C.I. in yellow ink used with such black ink. I. It is particularly preferable that the poor solvent for Pigment Yellow 74 is a poor solvent for carbon black in the black ink because bleeding can be suppressed particularly effectively. The component constituting the aqueous medium in the black ink used together with the ink according to the present invention is not particularly limited as long as it satisfies the above-described preferred structure, and is the same as the aqueous medium contained in the ink described above. Can be used.

[Additive]
In addition to the components described above, the black ink includes surfactants, pH adjusters, chelating agents, rust preventives, antiseptics, antifungal agents, ultraviolet absorbers, viscosity modifiers, antifoaming agents, and water solubility. You may contain various additives, such as a polymer. Such additives can be the same as those described above.

<Inkjet recording method>
The ink according to the present invention provides good results particularly when used in an ink jet recording method in which ink is ejected in accordance with a recording signal and recording is performed on a recording medium. A preferable inkjet recording method in this case includes a method of recording on a recording medium by applying thermal energy to the ink.

<Ink cartridge>
Examples of the ink cartridge suitable for performing recording using the ink according to the present invention include an ink cartridge having an ink containing portion for containing these inks. Specific examples of ink cartridges suitable for recording using the ink according to the present invention are shown below.

  FIG. 1 is a schematic explanatory view of an ink cartridge suitable for recording using the ink according to the present invention, and is a cross-sectional view. As shown in FIG. 1, the ink cartridge communicates with the atmosphere via the atmosphere communication port 112 at the upper portion and communicates with the ink supply port at the lower portion. The interior of the ink cartridge is partitioned by a partition wall 138 into a negative pressure generating member storage chamber 134 that stores a negative pressure generating member and a substantially sealed liquid storage chamber 136 that stores liquid ink. 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 ink cartridge and the atmosphere for promoting the introduction of the atmosphere into the liquid storage chamber during the liquid supply operation. It communicates only through the introduction groove (atmosphere introduction path) 150. A plurality of ribs are integrally formed on the upper wall of the ink cartridge constituting the negative pressure generating member storage chamber 134 so as to protrude inside, and the negative pressure stored in the negative pressure generating member storage chamber 134 in a compressed state. It is in contact with the generating member. 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 example, in the negative pressure generating member storage chamber, two of the first negative pressure generating member 132B and the second negative pressure generating member 132A, which are made of olefin resin fibers such as polyethylene, are used as the negative pressure generating member. Two capillary force generating negative pressure generating members are 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 the posture when the ink cartridge 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 of another ink cartridge suitable for recording using the ink according to the present invention, and is a cross-sectional view. As shown in FIG. 2, the 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 store three colors of ink. These three spaces are arranged along the insertion direction of the color ink cartridge when the color ink cartridge is mounted in the ink cartridge 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 stored 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.

Hereinafter, the present invention will be described more specifically with reference to Examples , Reference Examples, and Comparative Examples. The present invention is not limited by the following examples as long as the gist thereof is not exceeded. In the following description, “parts” and “%” are based on mass unless otherwise specified.

<Evaluation of ink>
Here, the ink which is one embodiment of the present invention was prepared by the following procedure, and the obtained ink was evaluated as follows.

(Preparation of yellow pigment dispersion)
10 parts of a pigment (CI Pigment Yellow 74), 20 parts of a dispersant and 70 parts of ion-exchanged water were mixed and dispersed for 3 hours using a batch type vertical sand mill. Thereafter, coarse particles were removed by centrifugation. Further, the mixture was filtered under pressure through a microfilter (manufactured by Fuji Film) having a pore size of 3.0 μm to prepare a yellow pigment dispersion. Then, it adjusted with water so that a pigment concentration might be 10%, and obtained the yellow pigment dispersion liquid. As the dispersant, an aqueous solution obtained by neutralizing a styrene-acrylic acid copolymer having an acid value of 200 and a weight average molecular weight of 10,000 with a 10% aqueous sodium hydroxide solution was used.

(Determination of poor and good solvents for each water-soluble organic solvent)
In order to select a water-soluble organic solvent that acts as a poor solvent and a good solvent for the yellow pigment dispersion obtained above, the following experiment was conducted. First, a 10% solid concentration aqueous solution of the yellow pigment dispersion obtained above was prepared, and using this and each water-soluble organic solvent, a dispersion for determining poor and good solvents at the following blending ratio: X and an aqueous dispersion Y for determination were prepared.

[Dispersion liquid X for determination]
・ Yellow pigment dispersion 50 parts ・ 50 parts of each water-soluble organic solvent listed in Table 1 [determination water dispersion Y]
・ Yellow pigment dispersion 50 parts ・ Pure water 50 parts

  Next, 10 g of each of the determination dispersion X and the determination water dispersion Y prepared as described above were put in a transparent glass lidded sample bottle, capped, and then sufficiently stirred. The mixture was left at 48 ° C. for 48 hours. Thereafter, the average particle size of the pigment in the dispersion was measured using a concentrated dispersion particle size analyzer (trade name: FPAR-1000; manufactured by Otsuka Electronics Co., Ltd.) using the dispersion as a measurement sample. A water-soluble organic solvent in which the average particle diameter of the pigment in the determination dispersion X and the determination aqueous dispersion Y after storage at 60 ° C. for 48 hours is larger than that of the determination aqueous dispersion Y is poor. The solvent was determined. A water-soluble organic solvent having an average particle size of the determination dispersion X after storage at 60 ° C. for 48 hours equal to or less than that of the determination aqueous dispersion Y was determined as a good solvent.

  By measuring the average particle size as described above, for the four types of water-soluble organic solvents shown in Table 1, the poor solvent and the good solvent were compared with the pigment dispersion in the yellow pigment dispersion prepared earlier. Judgment was made as to which case. The evaluation results are shown in Table 1. The results in Table 1 were shown as ◯ when judged as a good solvent and as x when judged as a poor solvent.

(Measurement of Ka value of each water-soluble organic solvent)
First, in measuring the Ka value of each water-soluble organic solvent, a dye aqueous solution having a dye content of 0.5% and having the following composition was prepared. The reason why such an aqueous dye solution is used is that it is visualized by coloring a colorless and transparent aqueous solution to facilitate measurement of the Ka value.
・ C. I. Direct Blue 199 0.5 part, Pure water 99.5 parts

Next, a 20% aqueous solution of a colored water-soluble organic solvent having the following composition was prepared from the 0.5% dye aqueous solution and each water-soluble organic solvent to be measured.
80 parts of the above 0.5% dye aqueous solution 20 parts of the water-soluble organic solvent listed in Table 1

  Using the 20% aqueous solution of each water-soluble organic solvent prepared above as a sample for measurement, using a dynamic permeability test apparatus (trade name: dynamic permeability test apparatus S; manufactured by Toyo Seiki Seisakusho), the Bristow method The Ka value of a 20% aqueous solution of each water-soluble organic solvent was determined. Table 1 shows the measurement results of the Ka value in a 20% aqueous solution of each water-soluble organic solvent that can be used in the ink, measured as described above.

(Preparation of ink)
The components shown in Tables 2 to 4 below were mixed and sufficiently stirred, and then pressure filtration was performed with a micro filter (manufactured by Fuji Film) having a pore size of 3.0 μm. Reference Examples 1 to 8 and Examples 9 to 25 and Comparative Examples 1 to 11 were prepared. Further, Reference Examples 1 to 8 obtained above, the inks of Examples 9-25 and Comparative Examples 1 to 11, using a Kyowa CBVP-2 formula surface tension meter (Kyowa Science), the surface of the ink at 25 ° C. Tension was measured. The measured surface tension of the ink is shown in Tables 2 to 4. Tables 2 to 4 show the pigment content A (%), the poor solvent content B (%), the good solvent content C (%), and the dye content D (in each ink). %) And B / A, C / B, A / D × 100 or D / A × 100 (%).

[Evaluation of color development and bleeding]
The following evaluation was performed using the inks of Reference Examples 1 to 8, Examples 9 to 13 and Comparative Examples 1 to 11 prepared above, and the black inks 1 to 3 shown below.

(Preparation of black pigment dispersion 1)
10 parts of carbon black having a specific surface area of 210 m ² / g and DBP oil absorption of 74 ml / 100 g, 20 parts of a dispersant, and 70 parts of ion-exchanged water were mixed and dispersed for 1 hour using a sand grinder. Thereafter, coarse particles were removed by centrifugation. Further, the mixture was filtered under pressure through a micro filter (manufactured by Fuji Film) having a pore size of 3.0 μm to prepare a black pigment dispersion 1. Then, it adjusted with water so that a pigment concentration might be 10%, and the black pigment dispersion liquid 1 was obtained. As the dispersant, an aqueous solution obtained by neutralizing a styrene-acrylic acid copolymer having an acid value of 200 and a weight average molecular weight of 10,000 with a 10% aqueous sodium hydroxide solution was used.

(Preparation of black pigment dispersion 2)
To a solution prepared by dissolving 5 g of concentrated hydrochloric acid in 5.5 g of water, 1.5 g of 4-aminophthalic acid was added while being cooled to 5 ° C. Next, the container containing the solution was placed in an ice bath and the solution was stirred to keep the solution constantly at 10 ° C. or lower, and 1.8 g of sodium nitrite was dissolved in 9 g of water at 5 ° C. The solution was added. After the solution was further stirred for 15 minutes, 6 g of carbon black having a specific surface area of 220 m ² / g and a DBP oil absorption of 105 mL / 100 g was added with stirring. Thereafter, the mixture was further stirred for 15 minutes. The obtained slurry was filtered with a filter paper (trade name: Standard filter paper No. 2; manufactured by Advantech), and then the particles were sufficiently washed with water and dried in an oven at 110 ° C. to prepare self-dispersing carbon black. Thereafter, the black pigment dispersion 2 was obtained by adjusting with water so that the pigment concentration was 10%.

(Determination of poor and good solvents for each water-soluble organic solvent)
The water-soluble organic that acts as a poor solvent and a good solvent for the black pigment dispersions 1 and 2 obtained above by the same method as the determination of the poor solvent and the good solvent of each water-soluble organic solvent for the yellow pigment dispersion Experiments were conducted to select the solvent. With respect to the four types of water-soluble organic solvents shown in Table 5, it was determined whether the solvent was a poor solvent or a good solvent for the pigment dispersion in the black pigment dispersion. The evaluation results are shown in Table 5. The results in Table 5 were shown as ◯ when judged as a good solvent and as x when judged as a poor solvent.

(Preparation of black ink)
After mixing each component shown in the following Table 6 and stirring sufficiently, pressure filtration was performed with a micro filter (manufactured by Fuji Film) having a pore size of 3.0 μm to prepare black inks 1 to 3.

(Preparation of recorded material)
An ink jet recording apparatus (trade name: PIXUS 950i; manufactured by Canon Inc.) that discharges ink by the action of thermal energy was used for the production of recorded matter. Specifically, the ink cartridge having the configuration of FIG. 1 was filled with each of the inks obtained above, and the ink cartridge was mounted on the ink jet recording apparatus to form an image. Then, using each ink of Reference Examples 1 to 8, Examples 9 to 13 and Comparative Examples 1 to 11, and Black Ink 1, yellow ink and black ink were applied to the following four types of copy paper (plain paper). A recording was formed on which a solid image of 2 cm × 2 cm was formed in a state where the two adjacent to each other.

The printer driver selected the default mode. The default mode setting conditions are as follows.
-Paper type: Plain paper-Print quality: Standard-Color adjustment: Automatic

As the recording medium, the following four types of copy paper (plain paper) were used.
・ PPC paper PB (Canon)
・ PPC paper 4024 (Xerox)
・ PPC paper prober bond (manufactured by Fox River)
・ Canon PPC paper (made by Neuzidra)

(Color development and bleeding)
One day after producing the recorded matter, the degree of bleeding at the portion where the image formed with the black ink 1 and the image formed with the inks of Examples and Reference Examples were adjacent was visually observed. Similarly, the degree of bleeding in the portion where the image formed with the black ink 1 and the image formed with the ink of the comparative example are adjacent to each other is visually observed and compared with the recorded materials of the examples and the reference examples. Evaluation was performed. Further, the optical density in the yellow image was measured using Macbeth RD915 (manufactured by Macbeth). The evaluation criteria for color development and bleeding are as follows. Table 7 shows the evaluation results. Note that the evaluation results in Table 7 were common to any recording medium.

A: Both the color developability and the suppression of bleeding are clearly superior to the image formed with the ink of the comparative example.
B: Compared with the image formed with the ink of the comparative example, either color development or bleeding suppression is superior.
C: There is no difference in color development and suppression of bleeding compared to an image formed with the ink of the comparative example.

The evaluation results of Examples 11 and 12, Reference Examples 6-8, as compared Examples 9-10 and 13, and, in any chromogenic and bleeding suppression also had become better results.

Using the black ink 2 instead of the black ink 1, a recorded material on which a 2 cm × 2 cm solid image in which the yellow ink and the black ink 2 of Reference Example 1 were adjacent to each other was formed in the same manner as described above. Immediately after producing the recorded matter, the degree of bleeding in the portion where the image formed with the black ink 2 and the image formed with the ink of the example and the reference example are adjacent to each other is visually observed, and the yellow of the reference example 1 described above is observed. Evaluation was performed in comparison with a recorded matter prepared with ink and black ink 2. As a result, the recorded matter produced using the black ink 2 had a better suppression of bleeding than the recorded matter produced using the black ink 1.

Using the black ink 3 in place of the black ink 2, a recorded matter in which a 2 cm × 2 cm solid image in which the yellow ink and the black ink 3 of Reference Example 1 were adjacent to each other was produced in the same manner as described above. Immediately after producing the recorded matter, the degree of bleeding in the portion where the image formed with the black ink 3 and the image formed with the ink of the example and the reference example were adjacent was visually observed, and the yellow of the reference example 1 described above was observed. Evaluation was performed in comparison with a recorded matter prepared with ink and black ink 2. As a result, the recorded matter produced using the black ink 3 had a better suppression of bleeding than the recorded matter produced using the black ink 2.

[Evaluation of saturation of red image]
The following evaluations were performed using the inks of Examples 14 to 25 and Comparative Examples 8 to 11 prepared earlier and the magenta ink shown below.
・ C. I. Acid Red 52 2.4%
・ Glycerin 3.6%
・ Polyethylene glycol 1000 1.0%
・ Surfinol 465 (surfactant; manufactured by Nissin Chemical Industry) 1.0%
・ Water 92.0%

(Preparation of recorded material)
An ink jet recording apparatus (trade name: PIXUS 950i; manufactured by Canon Inc.) that discharges ink by the action of thermal energy was used for the production of recorded matter. Specifically, the ink cartridge having the configuration shown in FIG. 1 is filled with each of the inks obtained above, and this ink cartridge is mounted on the ink jet recording apparatus. Then, using each of the inks of Examples 14 to 25 and Comparative Examples 8 to 11, 2 cm × 2 cm solid images of each color were formed. Each ink was mixed with magenta ink at a mass ratio of 50:50 on the recording medium to form a solid image (secondary color image) of 2 cm × 2 cm. The printer driver and the recording medium were the same as described above.

(Saturation of red image)
One day after producing the recorded matter, the saturation in the yellow image and the secondary color image was measured using Spectrolino (manufactured by Gretag Macbeth). The saturation can be obtained by the equation c ^* = (a ^{* 2} + b ^{* 2} ) ^1/2 . The evaluation criteria for saturation are as follows. The evaluation results are shown in Table 8. The evaluation results in Table 8 were common to any recording medium used.

A: Compared with the image formed with the ink of the comparative example, both the saturation of the yellow image and the secondary color image are clearly superior.
B: Compared with the image formed with the ink of the comparative example, it is clearly superior in the saturation of one of the yellow image and the secondary color image.
C: Compared to the image formed with the ink of the comparative example, there is no difference in the saturation of the yellow image and the secondary color image.

  In Examples 19, 22 and 23, although the types and contents of the dyes and pigments contained in the ink are exactly the same, the saturation of the yellow image and the secondary color image of Example 23 is the highest. It was good. Also, the degree of saturation of Example 22 was slightly inferior to that of Example 23, but the saturation of the yellow image and the secondary color image was better than that of Example 19.

  The recorded materials prepared in Examples 9, 13, 24 and 25 were set in a low-temperature cycle xenon weather meter (trade name: XL-75C; manufactured by Suga Test Instruments Co., Ltd.). One week exposure at 55% condition. The degree of uniformity in the yellow solid image before and after the light resistance test was visually confirmed to evaluate the fading balance. As a result, compared to Example 9, Example 13 was inferior in uniformity. Further, the uniformity of Example 25 was inferior to that of Example 24.

[Evaluation of storage stability]
Each of the inks of Reference Examples 1 to 8 and Examples 9 to 25 prepared previously were placed in a shot bottle, sealed, and stored in an oven at 60 ° C. for 2 weeks. The average particle diameter of the pigment and the viscosity of the ink were measured before and after storage at 60 ° C., respectively, and the change rate of the average particle diameter and the change rate of the viscosity were obtained, and evaluation was performed based on the obtained change rates. The evaluation criteria for storage stability are as follows. Table 9 shows the evaluation results.

A: The change rate of the average particle diameter of the pigment or the change rate of the viscosity of the ink is 5% or less before and after storage at 60 ° C.
B: The change rate of the average particle diameter of the pigment or the change rate of the viscosity of the ink is more than 5% and 10% or less before and after storage at 60 ° C.
C: After storage at 60 ° C., the ink changes to a gel, the upper part of the ink is transparent, or the ink is clearly thickened.

<Evaluation of inkjet ink production method>
Here, the ink obtained by the ink jet ink manufacturing method according to another embodiment of the present invention was evaluated.

  Each component shown in Table 10 below was mixed and sufficiently stirred, and then pressure filtration was performed with a microfilter (manufactured by Fuji Film) having a pore size of 3.0 μm to prepare ink A. This ink A is C.I. I. Pigment Yellow 74 and the C.I. I. It contains a poor solvent for Pigment Yellow 74.

  14.5 g of ink A prepared according to the formulation shown in Table 10 was injected into the ink cartridge having the configuration shown in FIG. Thereafter, 12.5 g of ink was discharged from the ink cartridge. Thereafter, 10.0 g of each of the ink cartridges prepared in Comparative Examples 1 to 6 was filled in the ink cartridges to prepare inks of Examples 26 to 31. When these inks were extracted from the ink cartridge and the composition was analyzed, the compositions shown in Table 11 below were found.

(Preparation of recorded material)
A recorded matter was produced using each of the inks of Examples 26 to 31. An ink jet recording apparatus (trade name: PIXUS 950i; manufactured by Canon Inc.) that discharges ink by the action of thermal energy was used for the production of recorded matter. Specifically, the ink cartridge obtained above was mounted on the ink jet recording apparatus to form an image. Then, using each of the inks of Examples 26 to 31, evaluation was performed by the same method and standard as the evaluation of color developability and bleeding performed in Reference Example 1. The evaluation results are shown in Table 12. In addition, the comparative example in the evaluation criteria in this case is Comparative Examples 1-11 similarly to the above.

It is a schematic explanatory drawing of the ink cartridge suitable for performing recording using the ink concerning this invention. It is a schematic explanatory drawing of the ink cartridge suitable for performing recording using the ink concerning this invention. FIG. 3 is a schematic explanatory diagram from when ink is applied to a recording medium until fixing.

Explanation of symbols

41: Container 42: Lid members 43Y, 43M, 43C: Ink supply ports 44Y, 44M, 44C: Ink absorbers 45Y, 45M, 45C: Ink supply member 46: Retaining claw 47: Latch lever 47c: Base slope 48: Latch Claw 49: Stepped portion 112: Atmospheric communication port 114: Liquid supply port 132A: Second negative pressure generating member 132B: First negative pressure generating member 132C: First negative pressure generating member and second negative pressure generating member Boundary layer 134: negative pressure generating member storage chamber 136: liquid storage chamber 138: partition wall 140: communication hole 146: pressure contact body 150: air introduction groove (atmosphere introduction path)
411, 412: Partition plate L: Liquid-gas interface 1300: Recording medium 1301: C.I. I. Pigment Yellow 74
1302: Dye 1303: C.I. I. Aggregates of Pigment Yellow 74

Claims (16)

An inkjet ink comprising water, a coloring material, and a water-soluble organic solvent,
The color material is C.I. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132, and C.I. I. One or more dyes selected from the group consisting of Direct Yellow 59, and C.I. I. Pigment Yellow 74,
The surface tension of the ink is 34.0 mN / m or more,
The water-soluble organic solvent is the C.I. I. A poor solvent for Pigment Yellow 74,
In the ink, the C.I. I. An inkjet ink, wherein a ratio (B / A) of the content B (mass%) of the poor solvent to a content A (mass%) of Pigment Yellow 74 is 0.75 or more and 4 or less.   In the ink, the C.I. I. 2. The inkjet ink according to claim 1, wherein the ratio (B / A) of the content B (mass%) of the poor solvent to the content A (mass%) of Pigment Yellow 74 is 1 or more and 4 or less.   The inkjet ink according to claim 1, wherein the ink has a surface tension of 41.0 mN / m or less.   In the ink, the C.I. I. The value of A / D × 100% is 7% or more and 34% or less when the content A (mass%) of Pigment Yellow 74 is smaller than the content D (mass%) of the dye. An ink-jet ink according to claim 1.   In the ink, the C.I. I. The value of D / A × 100% is 5% or more and 25% or less when the content A (mass%) of Pigment Yellow 74 is larger than the content D (mass%) of the dye. An ink-jet ink according to claim 1. The water-soluble organic solvent is the C.I. I. Including a good solvent for Pigment Yellow 74,
The ratio (C / B) of the content C (mass%) of the good solvent to the content B (mass%) of the poor solvent in the ink is 0.3 or more and 2 or less. 6. The inkjet ink according to any one of 5 above.   The inkjet ink according to claim 1, wherein the poor solvent is at least one selected from polyethylene glycol having an average molecular weight of 1,000, 2-pyrrolidone, and 1,5-pentanediol. . The inkjet ink according to any one of claims 1 to 6, wherein the poor solvent is polyethylene glycol having an average molecular weight of 1,000. The inkjet ink according to any one of claims 6 to 8, wherein the good solvent is at least one selected from glycerin and ethylene glycol. C. above. I. The inkjet ink according to any one of claims 1 to 9, wherein the pigment yellow 74 is dispersed by the action of an ionic group. An inkjet ink manufacturing method for obtaining the inkjet ink according to any one of claims 1 to 10 ,
C. I. Pigment yellow 74, and the C.I. I. An ink cartridge containing a poor solvent for Pigment Yellow 74 and containing ink having a surface tension of 34.0 mN / m or more is used as a coloring material. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132 and C.I. I. A method for producing an ink-jet ink, comprising a step of injecting an ink-jet ink containing one or more dyes selected from the group consisting of direct yellow 59. An inkjet ink obtained by the method for producing an inkjet ink according to claim 11 . In an inkjet recording method for ejecting ink by an inkjet method,
The ink jet recording method which comprises using the ink jet ink according to any one of claims 1 to 10 and 1 2. In the ink cartridge comprising an ink storage portion for storing ink, and characterized in that the housing portion of the ink, formed by accommodating the ink jet ink according to any one of claims 1 to 10 and 1 2 Ink cartridge to use. A yellow ink used together with a black ink containing water, carbon black, and a water-soluble organic solvent,
Water, a coloring material, and a water-soluble organic solvent. I. Direct Yellow 86, C.I. I. Acid Yellow 23, C.I. I. Direct Yellow 173, C.I. I. Direct Yellow 132 and C.I. I. One or more dyes selected from the group consisting of Direct Yellow 59, and C.I. I. Pigment Yellow 74,
The surface tension of the ink is 34.0 mN / m or more,
The water-soluble organic solvent is the C.I. I. A poor solvent for Pigment Yellow 74,
In the ink, the C.I. I. A yellow ink, wherein a ratio (B / A) of the content B (mass%) of the poor solvent to a content A (mass%) of Pigment Yellow 74 is 0.75 or more and 4 or less. C. above. I. The yellow ink according to claim 15 , wherein the poor solvent for pigment yellow 74 is also a poor solvent for carbon black in the black ink used together.

Images