JP2000273374A - Inkjet recording ink set - Google Patents

Abstract

(57) [Problem] To provide an ink jet recording ink set excellent in coloring property and light resistance in all of cyan, magenta and blue colors. SOLUTION: Cyan ink, magenta ink,
It is characterized by comprising at least a cyan color material contained in the cyan ink and a blue ink containing a magenta color material having a xanthene structure not contained in the magenta ink. The weight ratio of the cyan color material in the blue ink to the cyan color material in the cyan ink is in the range of 1: 1 to 1: 2, and the content ratio of the cyan color material and the magenta color material in the blue ink. Is in the range of 1: 1 to 1: 2 by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink jet recording ink set suitable for recording a color image and storing the recorded image.

[0002]

2. Description of the Related Art In an ink jet recording method, ink droplets are ejected from nozzles provided in a recording head by vibration of a piezoelectric element or pressure by thermal energy.
This is a method for fixing an image on a recording medium to form an image, and is a recording method which is excellent in quietness and can form a high-resolution image at high speed without using any special fixing means. It is also suitable for forming color images from the viewpoint of structural simplicity and running cost. In recent years, in particular, ink jet recording methods and apparatuses for forming color images in personal computer output, graphic printing, and many other applications have been developed. Provided.

In a recording method for forming a color image, it is general to use at least three primary colors of cyan, magenta and yellow. In an ink jet recording method, four colors including black are used. Generally, image formation is performed. For example, red is expressed in a pseudo manner by applying or adjoining magenta and yellow to the same point on the recording medium. Similarly, blue is magenta and cyan, and green is cyan and yellow. These can be provided with further gradation by adjusting the amount of ink droplets and the number of applied inks, or by combining black.

[0004] The inks used in these ink jet recording methods have, for example, appropriate physical properties such as viscosity and surface tension, high optical density, giving clear colors and images, water resistance and light resistance. It is required to have various performances such as giving an image with excellent robustness, being excellent in storability, being unlikely to cause nozzle clogging, and being excellent in safety. Most of the performances are realized by using an aqueous ink in which a water-soluble dye is dissolved in a mixture of water and a water-soluble organic solvent.

[0005]

However, it is known that dyes, when exposed to sunlight, tend to undergo discoloration due to the ultraviolet light contained therein. Conventionally,
In order to improve the light fastness of recorded images, a method of changing the color material to a pigment with excellent light fastness, a method of using a dye with superior light fastness, and the coloring material is provided with light fastness while using a conventional dye A method of adding various additives has been considered.

[0006] When a pigment is used, the light resistance of the recorded image itself is much higher than that of an ink using a dye as a coloring material because of the light resistance of the pigment itself. However, in general, pigments are insoluble in water and must be mixed with a resin called a dispersant to prepare an aqueous ink in order to be used as an aqueous ink. For this reason, solvents that can be used in inks are restricted compared to dyes, and pigments tend to have lower color developability and saturation than dyes, and there are few types of colorants that can be used and poor color expression. have.

[0007] For this reason, many methods have been provided for increasing the light fastness of inks using dyes having excellent coloring properties as coloring materials.

For example, Japanese Patent Application Laid-Open No. 5-311087 proposes a method using a dye having a specific structure as a coloring material of ink. Japanese Patent Application Laid-Open No. Sho 62-106971 discloses a method in which an ultraviolet absorber and an oxidizing agent are added to the ink. There has been proposed a method of improving the light fastness by adding an inhibitor. However, even dyes that are excellent in light resistance in ultraviolet light, those that undergo discoloration in an actual environment including visible light, and dyes that are excellent in light resistance in an environment including the visible region, In some cases, discoloration occurs due to color mixing with the dye, and a dye having sufficient light resistance has not yet been found. Further, additives also have an effect of suppressing discoloration and fading of the dye due to ultraviolet light, but it is a reality that these additives have little effect under an actual environment including visible light.

Japanese Patent Application Laid-Open No. Hei 6-53436 proposes a method of protecting a dye by laminating a recorded image using a PET (polyethylene terephthalate) film containing an ultraviolet absorber. However, in this case, since a film is stuck on the image to cover it,
Since the color development performance inherent in the dye is impaired and the image quality is deteriorated, and the lamination process itself is increased, it is difficult to say that it is an effective means because it lacks simplicity in general homes and offices. Furthermore, PET films are also effective in discoloring and fading dyes due to ultraviolet light, but have not been able to provide a sufficient effect under actual environments including visible light.

As a cause of discoloration in a real environment including visible light, some dyes themselves act as a singlet oxygen sensitizer in the presence of light and oxygen to generate singlet oxygen, In the case where the dye itself is oxidized by singlet oxygen and the case where inks of different hues are ejected as in an ink jet recording apparatus and multicolor color expression is performed by an ejection ratio (mixing ratio), a certain dye is used. Acts as a singlet oxygen sensitizer, and the generated singlet oxygen reacts with other adjacent or mixed dyes to promote the discoloration and fading of the dye.

The former case can be solved by selecting a dye which does not generate a self-sensitizing photooxidation reaction. The latter case can also be solved by using no dye serving as a sensitizer for singlet oxygen.However, in the case of cyan ink, a copper phthalocyanine dye is generally used in terms of light resistance and color development. This copper phthalocyanine dye acts as a sensitizer for singlet oxygen, and partially promotes the photodegradation of the magenta dye. It was also found that discoloration and discoloration tended to accelerate.

In particular, magenta dyes that are liable to undergo discoloration and discoloration under the influence of singlet oxygen are azo-based dyes, and the magenta dyes themselves often have excellent coloring properties and light fastness. In other words, the light fastness in a single color is very excellent, but the discoloration and discoloration are remarkable in a portion adjacent to or mixed with cyan (copper phthalocyanine), and when viewed as a color image, the light fastness is largely inferior.

Therefore, cyan dyes that do not promote the photodegradation of magenta dyes have been studied, but no cyan dyes having both color developing property and light fastness have been found yet. In JP-A-1-95093, a dark and light cyan ink is used, and a copper phthalocyanine dye having a high coloring property is used for the dark ink, and a cyan dye which has a poor coloring property but does not promote light deterioration of magenta is used for the light ink. The method used has been proposed. However, this method does not provide any improvement in the mixed color portion of the dark cyan ink and the magenta ink.

Further, magenta dyes which do not cause photodegradation in a mixed color portion with a copper phthalocyanine dye have been studied, but a magenta dye having both color developing property and light fastness has not been found yet. In this case, light degradation is relatively easy to occur in the lighter part (it is more conspicuous).
In Japanese Patent No. 82, while using a copper phthalocyanine dye for the cyan ink, a dark and light ink is used for the magenta ink, a dye that emphasizes the color developing property for the dark magenta ink, There has been proposed a method of using a dye which does not discolor even when adjacent to or mixed with ink. However, also in this method, the improvement has no effect on the combination of the cyan ink and the dark magenta ink as in the case of the dark and light cyan ink described above, and in an actual image using these inks, No effect could be found.

That is, in the cyan ink and the magenta ink, the coloring property and the light resistance as a single color are maintained, and the secondary color (blue) generated by the combination of these is similarly high. Techniques showing color development and light fastness have not been found so far.

Regarding the blue color, see JP-A-60-104.
In Japanese Patent Application Publication No. 169, there is provided a method of realizing a blue color excellent in color tone and light fastness by using a blue ink using CI Direct Blue 199 and an arbitrary red dye in combination. In the case of using this method, when the blue ink is used in a single color, an image having excellent light fastness can be obtained by selecting a combination of the blue ink and the selection of the red dye. Is not considered when used in combination with other color inks, and image formation using a plurality of inks such as expressing a plurality of blue gradations and secondary colors in combination with other cyan inks or magenta inks. Is not sufficient for the ink jet recording to be performed.

Therefore, an object of the present invention is to solve these problems. In other words, it is possible to obtain a color image which is excellent in color developing properties for cyan and magenta single colors and shows sufficient light fastness, and also has sufficient color developing properties and light fastness for blue which is a secondary color thereof. Is provided.

[0018]

The above objects are achieved by the present invention. That is, the inkjet recording ink set of the present invention includes a cyan ink, a magenta ink,
An ink jet recording ink set, comprising at least a cyan color material contained in the cyan ink and a blue ink containing a magenta color material having a xanthene structure not contained in the magenta ink. is there.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording ink set according to the present invention is preferably used by adding a yellow ink to the ink set, and more preferably a black ink to these inks.

The ink-jet recording ink set of the present invention contains a cyan ink as a first ink, a magenta ink made of a magenta color material having no xanthene structure as a second ink, and a cyan ink as a third ink. A blue ink containing a cyan color material and a magenta color material having a xanthene structure not contained in the magenta ink.

The cyan color material contained in the cyan ink and the blue ink is not particularly limited as long as it is suitable for forming the cyan ink. Considering that
Generally, metal phthalocyanine-based dyes, particularly copper phthalocyanine-based direct dyes, are more preferable. Specific examples include CI Direct Blue 199 and the like.

In the ink set of the present invention, the addition amount of the cyan coloring material contained in the blue ink is 1: 1 to 1: 1 with respect to the amount (weight ratio) contained in the cyan ink.
It is desirable to be in the range of 2. If less than 1: 2,
The cyan color of the blue ink is too small, and when an image is formed with two inks of blue and cyan, the blue color fades. Conversely, if the ratio is more than 1: 1, the image becomes very noticeable with respect to the cyan color, and the image becomes as if the blue color is raised. Therefore, the ratio of the blue color ink to the cyan color material contained in the cyan ink is within the above range. It is preferable to use it.

As the magenta coloring material used for the blue ink, a magenta dye having a xanthene structure is preferable. When an azo-based magenta dye, which is widely used in general, is used as a coloring material, when used together with the above-described cyan coloring material, it is deteriorated under the influence of singlet oxygen generated from the cyan coloring material, and a blue color is produced. Be impaired. On the other hand, a magenta dye having a xanthene structure has poor light fastness in a single color and is not suitable as a coloring material for a magenta ink, but when used together with the above-described cyan coloring material, a blue color excellent in light fastness can be realized. It becomes possible. The reason is not clear, but one is that the xanthene structure does not undergo accelerated degradation because it is not affected by the promotion of degradation by singlet oxygen,
The other is presumed to be less likely to be discolored because the effect of light on the barrier effect of the cyan coloring material is reduced.

The magenta dye having a xanthene structure used in the present invention includes CI Acid Red 50,
1, 52, 87, 91, 92, 93, 94, 95, 9
8, 289 and the like.

In the ink jet recording ink set of the present invention, the addition ratio of the cyan color material and the magenta color material contained in the blue ink may be in the range of 1: 1 to 1: 2 by weight. preferable. In a general ink jet recording apparatus, the basic colors are three primary colors of yellow, magenta, and cyan, or four primary colors obtained by adding black thereto, and a single color is used alone, and two or more colors are mixed from these. Is used to realize a secondary color. The secondary color is not limited to the blue color, and the mixing ratio is not necessarily 1: 1, but a secondary color having a plurality of gradation expressions is formed by an arbitrary mixing ratio. I do.

On the other hand, in the ink jet recording ink set of the present invention, a blue ink is used as one of the primary colors by using a blue ink, and arbitrary mixing with cyan and magenta is performed to give a gradation. At this time,
When the addition ratio of the cyan color material to the magenta color material having a xanthene structure contained in the blue ink is more than 1: 1, the cyan color becomes too strong and the blue color closer to magenta is expressed. When mixing with magenta ink, the proportion of magenta ink must be increased. However, in this case, the magenta color material used for the magenta ink fades due to the cyan color material contained in the blue ink, and the formed blue color cannot maintain light resistance. If the ratio is less than 1: 2, the light deterioration of the magenta colorant having the xanthene structure in the blue ink is conspicuous, and the light resistance of the blue ink itself cannot be secured.

The present inventors have proposed that when a blue color closer to magenta is expressed when used in the range of 1: 1 to 1: 2, if the blue ink and the magenta ink of the ink set of the present invention are used, It has been found that even when mixed and used, fading of the coloring material contained in the magenta ink is suppressed, and light resistance can be sufficiently maintained. It is presumed that the effect is small because the ratio of the magenta ink is low, and that the effect of singlet oxygen is blocked by the magenta coloring material in the blue ink having a xanthene structure.

In the ink jet recording ink set of the present invention, a cyan ink, a magenta ink,
The amount of the coloring material added to the blue ink is 0.1 to 10 for each ink in consideration of clogging and ejection stability.
It is desirable to use it in the range of wt%.

The ink-jet recording ink set of the present invention is preferably used for expressing more tones and colors by using a yellow ink, preferably a black ink, and more preferably a black ink. .

Further, as the solvent used for the ink constituting the ink set of the present invention, water or a mixture of water and a water-soluble organic solvent is preferable. As the water-soluble organic solvent, a low-volatile solvent is preferable from the viewpoint of suppressing clogging. For example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, 1,3-propanediol, 1,2 Polyhydric alcohols such as 1,6-hexanetriol and glycerin; ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether;
Glycol ethers such as dipropylene glycol monomethyl ether; formamide, dimethylformamide, diethanolamine, triethanolamine, 1,
Nitrogen-containing solvents such as 3-dimethyl-2-imidazolidinone, 2-pyrrolidone, and N-methyl-2-pyrrolidone; and sulfur-containing solvents such as thiodiglycol and dimethylsulfoxide.

These solvents may be used alone,
Two or more kinds may be used in combination, and the content is 3 to 40% by weight, preferably 3 to 30% by weight based on the whole ink.
Range. If the content is less than 3 wt%, clogging at the nozzle tip is likely to occur quickly, and if it exceeds 40 wt%, the dryness of the recorded image is reduced, and the image is blurred and the print quality is reduced. This is because a phenomenon occurs.

The ink constituting the ink set of the present invention includes lower alcohols such as ethanol, 1-propanol and 2-propanol, fatty acid salts, and alkyl sulfates in order to promote drying of the ink after image formation. It is preferable to include an anionic surfactant such as an ester salt, or a nonionic surfactant such as acetylene glycols, polyoxyethylene alkyl ethers, and polyethylene fatty acid esters. In the case of lower alcohols, the content is 2 to 10% by weight, preferably 2 to 6% by weight.
% In the case of a surfactant, and 0.01 to 2 wt.
% Is desirable. If the content of each is less than this, sufficient effect to promote the drying property is not obtained, and if the content is too large, bleeding occurs in a printed image, and the ejection stability of ink droplets is affected, and printing quality is deteriorated. May be caused.

In the ink of the ink set of the present invention, bleeding at the boundary between adjacent color inks is a major problem in print quality. However, the above-mentioned acetylene glycol-based nonionic surfactant and By including glycol ethers, this problem is solved, and a clear image without bleeding at the boundary can be obtained. More preferably, by using an acetylene glycol-based nonionic surfactant and a glycol ether in combination, a clearer and more excellent print quality color image can be obtained.

Examples of the acetylene glycol-based nonionic surfactant include Olfin E1010, Olfin STG, and Surfynol 104E (all products of Nissin Chemical Industry Co., Ltd.).

As the glycol ethers, the above-mentioned water-soluble organic solvents are preferred, and particularly preferred are diethylene glycol monobutyl ether, triethylene glycol monobutyl ether and propylene glycol monobutyl ether. Also, the amount of addition is the same as that of the above-mentioned water-soluble organic solvent, and it is more preferable that it is selected in the range of 3 to 30 wt%. If less than 3 wt%, almost no effect is obtained, and 30 wt%
Above, on the contrary, bleeding becomes large, and the whole image is blurred, and conversely, the print quality is degraded. Therefore, it is preferable to use it within the described range.

Further, the ink constituting the ink set of the present invention may contain a water-soluble polymer or a water-soluble resin, if necessary.
An antifoaming agent, a pH adjusting agent, a preservative, a rust inhibitor, and the like may be included.

[0037]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

The inks 1 to 11 described below can be produced by a conventional method. For example, there is a method in which, after sufficiently mixing and dissolving each component, pressure filtration is performed with a membrane filter having a pore size of 1 μm, and this is deaerated to prepare an ink.

Ink 1 (blue) C.I. I. Direct Blue 199 2wt% C.I. I. Acid Red 289 2.5 wt% Triethylene glycol 20 wt% Triethylene glycol monobutyl ether 10 wt% Orfin E1010 (manufactured by Nissin Chemical Industry) 1 wt% Deionized water 64.5 wt% Ink 2 (blue) I. Direct Blue 199 2wt% C.I. I. Direct Red 227 2.5 wt% Triethylene glycol 20 wt% Triethylene glycol monobutyl ether 10 wt% Orfin E1010 1 wt% Ion exchange water 64.5 wt% Ink 3 (blue) I. Direct Blue 199 2wt% C.I. I. Acid Red 52 2% by weight Diethylene glycol 20% by weight Triethylene glycol monobutyl ether 10% by weight Orfin E1010 1% by weight Ion exchange water 65% by weight Ink 4 (blue) I. Direct Blue 199 2.5 wt% C.I. I. Acid Red 289 1.5 wt% Diethylene glycol 20 wt% Triethylene glycol monobutyl ether 10 wt% Orfin E1010 1 wt% Deionized water 65.1 wt% Ink 5 (Blue) I. Direct Blue 199 3wt% C.I. I. Acid Red 52 1 wt% Diethylene glycol 20 wt% Triethylene glycol monobutyl ether 10 wt% Orfin E1010 1 wt% Ion exchange water 65 wt% Ink 6 (blue) I. Direct Blue 199 1wt% C.I. I. Acid Red 289 3 wt% Diethylene glycol 20 wt% Triethylene glycol monobutyl ether 10 wt% Orfin E1010 1 wt% Ion exchange water 65 wt% Ink 7 (magenta) I. Direct Red 227 2.5 wt% Triethylene glycol 24 wt% Triethylene glycol monobutyl ether 10 wt% Orfin E1010 1 wt% Ion exchange water 62.5 wt% Ink 8 (magenta) I. Acid Red 289 2.5 wt% triethylene glycol 24 wt% triethylene glycol monobutyl ether 10 wt% Orfin E1010 1 wt% ion exchange water 62.5 wt% Ink 9 (cyan) I. Direct Blue 199 3 wt% Diethylene glycol 23 wt% Triethylene glycol monobutyl ether 10 wt% Orfin E1010 1 wt% Ion exchange water 63 wt% Ink 10 (black) I. Direct Black 168 6 wt% Glycerin 11 wt% Ethylene glycol monobutyl ether 10 wt% Orfin STG (manufactured by Nissin Chemical Industry) 1 wt% Deionized water 72 wt% Ink 11 (yellow) I. . Direct Yellow 132 3 wt% Glycerin 10 wt% Diethylene glycol 10 wt% Triethylene glycol monobutyl ether 10 wt% Orphin STG 1 wt% Ion-exchanged water 66 wt% Combinations of Examples and Comparative Examples using these are described in Table 1.

[0040]

[Table 1]

The following tests were performed on these combinations using an ink jet recording apparatus: PM-5000C (a product of Seiko Epson Corporation). That is, the cyan chamber of the ink cartridge for the recording apparatus,
Each ink is injected into the magenta chamber, and blue ink is injected into the light-color cyan chamber and the light-color magenta chamber.In any case, the genuine ink cartridge of the recording apparatus is used for the black ink and the yellow ink. After attaching to the recording apparatus, the solid image of each of the magenta ink and the blue ink, the cyan ink and the blue ink
A solid image formed by alternately applying at 720 inch intervals (FIG. 1 (a)).
A solid image (FIG. 1 (b)) constituted by an application ratio of 1 and a solid image (FIG. 1 (c)) constituted by alternately applying magenta ink and blue ink at an interval of 1/720 inch. A solid image (FIG. 1 (d)) composed of 720 inch intervals at an application ratio of 3: 1 was created on a medium using EPSON Super Fine special paper (a product of Epson Sales Co., Ltd.) as a recording medium, and a print sample was prepared. I got However, only the comparative example 1 has no blue ink, and instead, a solid image formed by alternately applying magenta ink and cyan ink at an interval of 1/720 inch, similarly, an application ratio of 3: 1 at an interval of 1/720 inch Each of the print samples was obtained from the solid image composed of the above and the solid image similarly composed at an application ratio of 1: 3 at an interval of 1/720 inch.

The blue ink contained in the light-colored cyan chamber and the light-colored magenta chamber were the same, and only ink in one of the ink chambers was used for actual image formation. In addition, yellow ink and black ink are installed in order to normally operate the recording apparatus,
The evaluation in the present embodiment is not directly or indirectly involved.

Using a xenon weatherometer Ci35A (manufactured by ATLAS), a black panel temperature of 63 ° C. and a relative humidity of 50% were used for the print sample.
Exposure was performed for 60 hours at m ultraviolet light irradiance of 0.35 W / m ² . For these, the color difference generated before and after the test.
E ^* ab was converted to a spectrophotometer GRETAG-SPM50 (GR
(ETAG company product), and was determined according to the following criteria.

<Judgment Criteria> Color difference ΔE * ab is A: less than 5 B: 5 or more and less than 10 C: 10 or more and less than 20 NG: 20 or more The evaluation results are shown in Table 2.

[0045]

[Table 2]

[0046]

According to the ink jet recording ink and the recording method of the present invention, it is possible to obtain an image excellent in color developability and light resistance both in a single color of magenta and in a blue color with various gradations. Become.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a positional relationship of application of ink droplets on a print medium.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA13 FC02 4J039 BC31 BC33 BC68 BE04 CA03 CA06 EA15 EA16 EA17 EA19 EA35 EA42 GA24

Claims (3)

[Claims] 1. An ink jet recording ink set used in an ink jet recording apparatus, comprising: a cyan ink, a magenta ink, a cyan color material contained in the cyan ink, and a magenta color having a xanthene structure not contained in the magenta ink. An ink jet recording ink set comprising at least a blue ink containing a material. 2. The weight ratio of the cyan color material in the blue ink to the cyan color material in the cyan ink is 1: 1 to 1:
2. The ink jet recording ink set according to claim 1, wherein the range is 2. 3. The ink jet recording according to claim 2, wherein the content ratio of the cyan color material and the magenta color material contained in the blue ink is in a range of 1: 1 to 1: 2 by weight. Ink set.