JP2003128968A - Ink jet ink and ink jet cartridge using the same, ink jet image-recording method and ink jet recorded image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet ink which gives ink jet recorded images having excellent graininess, glossiness and light resistance, to provide an ink jet cartridge using the ink jet ink, to provide an ink jet image-recording method, and to provide an ink jet-recorded image. SOLUTION: This ink jet ink containing pigment particles and colored fine particles selected from colored fine particles comprising a resin containing a dye, colored fine particles comprising a resin coated with a dye, and colored fine particles obtained by coating the surfaces of a dye-containing resin with a resin is characterized in that a redispersion coefficient represented by the general formula (1) is 0.5 to 5 and further that the surfaces of the pigment particles are covered with water-insoluble and water-dispersible polymer layers. The formula (1): the redispersion coefficient = the second volume-average particle diameter of the colored fine particles and the pigment particles after redispersion/the second volume-average particle diameter of the colored fine particles and the pigment particles before redispersion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet ink, an inkjet cartridge using the same, an inkjet image recording method, and an inkjet recorded image.

[0002]

2. Description of the Related Art Ink jet recording is a technique for ejecting minute droplets of ink by various operating principles and adhering them to a recording medium to record images, characters, etc. It has an advantage that it can be easily colored.

In addition, due to recent technological advances, ink jet printing using dye ink is accelerating its widespread use with the high image quality approaching that of silver halide photography and the cost reduction of the apparatus.

The dye is soluble in a solvent, and the dye molecule is colored in a molecular state or a cluster state. Therefore,
Since the environment of each molecule is similar, its absorption spectrum is sharp, and it exhibits high purity and vivid color. Furthermore, since there is no granular pattern due to particles and scattered light or reflected light does not occur, it is possible to obtain an inkjet image having high transparency and a clear hue.

On the other hand, however, when the molecules are destroyed by a photochemical reaction or the like, the decrease in the number of molecules is reflected in the coloring density as it is, so that the light resistance is poor. Although an ink jet recorded image using a dye ink has a high image quality, the image quality is largely deteriorated due to storage over time, and a technique that surpasses silver salt photography from the viewpoint of image storability has not yet appeared.

In contrast to dye inks, pigment inks using pigments having good light resistance as colorants are used as inks for applications requiring an image resistant to fading by light. However, since the pigment is present as pigment particles as compared with the dye, it is more susceptible to light scattering and gives an image with no sense of transparency, so there is a drawback that the dye does not match the color reproducibility.

As described above, the dye ink is excellent in graininess, glossiness and color reproducibility, but is inferior in light resistance, and conversely, the pigment ink is excellent in light resistance. However, they have contradictory properties such as poor granularity, glossiness, and color reproducibility.

As a measure for solving the problems of the water-based ink using the water-soluble dye as described above, an emulsion,
The addition of resin fine particles such as latex has been studied for a long time. Japanese Patent Application Laid-Open No. 55-18418 proposes a recording agent for ink jet recording to which a latex which is "a kind of colloidal solution in which components such as rubber and resin are dispersed in water in the form of fine particles by an emulsifier" is added. is there. In order to improve light fastness by adding latex as in the patent proposal or to have a bleeding prevention effect,
It is very difficult to secure dispersion stability and discharge stability because more latex than the amount of dye used is required, and to obtain an image comparable to a photographic image in terms of graininess and glossiness. The current situation is that it has not arrived.

In order to solve the problems of low water resistance and light fastness of the water-based ink using the water-soluble dye, a method of coloring the water-dispersible resin with an oil-soluble dye, a hydrophobic dye or the like has been proposed as an ink jet recording. It is made as an ink. For example, JP-A-55-139471 and JP-A-58-4.
No. 5272, JP-A Nos. 3-250069 and 8-253.
No. 720, No. 8-92513, No. 8-183920.
JP-A 2001-11347 and the like propose inks using emulsion-polymerized particles dyed with an oil-soluble dye or dispersed polymerized particles. In a water-based ink using such colored fine particles, the presence of a dye on the particle surface or outside the particle reduces the light resistance effect, and enhances various properties such as dispersion stability, ejection stability, and light fastness. At present, it is difficult to obtain an image that is comparable to a photographic image in terms of graininess and glossiness as the obtained image.

Further, in JP-A-2001-19880, colored fine particles impregnated with a chelate dye are also disclosed in JP-A-20-18080.
No. 01-139607 proposes colored fine particles having a core-shell type double structure impregnated with a chelate dye, but none of them is at a satisfactory level for obtaining an image comparable to a photographic image.

Further, there is known an ink in which a dye ink is dissolved in a resin and dispersed in fine particles in the ink. However, by using a dye as a colored fine particle, the temperature and humidity are higher than those of a normal dye ink. Although bleeding and water resistance under the ink can be improved, there is a defect that the image bleeds when these inks are stored for a long time under high temperature and high humidity.

As described above, the colored fine particle-containing aqueous ink using a dye has a possibility of overcoming the problems of the conventional aqueous ink using a water-soluble dye and a pigment dispersion and realizing high recording quality. However, there are various problems remaining and further improvement is required.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet ink excellent in graininess, glossiness and light resistance of an ink jet recorded image and an ink jet using the same. A cartridge, an inkjet image recording method, and an inkjet recorded image are provided.

[0014]

The above objects of the present invention have been achieved by the following constitutions.

1. At least one kind of colored fine particles selected from colored fine particles made of a resin containing a dye, colored fine particles made of a resin coated with a dye, and colored fine particles having a surface of a resin containing a dye further coated with a resin; An ink jet ink containing the ink, the redispersion coefficient of the ink jet ink represented by the formula (1) is 0.5 to 5, and the surface of the pigment particle is water-insoluble and highly water-dispersible. An inkjet ink characterized by being coated with a molecular layer.

2. pH is 7.0 or more, The inkjet ink as described in the above item 1.

3. 3. The inkjet ink according to item 1 or 2, wherein the surface tension is 25 to 45 mN / m.

4. The secondary volume average particle diameter of the colored fine particles is 10 to 150 nm,
The ink-jet ink according to any one of item 3.

5. The secondary volume average particle diameter of the pigment particles is 10 to 150 nm,
The inkjet ink according to any one of 4 above.

6. 6. The inkjet ink according to any one of items 1 to 5, wherein the polyvalent metal ion content is 5 ppm or less.

7. Ink solvent content is 5-70% by mass
7. The inkjet ink according to any one of items 1 to 6, wherein:

8. Item 8. The inkjet ink according to any one of items 1 to 7, which contains an anionic surfactant.

9. Item 8. The inkjet ink according to any one of items 1 to 7, which contains a nonionic surfactant.

10. Item 8. The inkjet ink according to any one of Items 1 to 7, which contains a cationic surfactant.

11. Item 8. The inkjet ink according to any one of items 1 to 7, which contains an anionic surfactant and a nonionic surfactant.

12. 12. The inkjet ink according to any one of items 1 to 11, which contains a water-soluble polymer or a water-insoluble polymer dispersion.

13. 13. An inkjet cartridge having an ink containing portion containing at least one inkjet ink according to any one of 1 to 12 above.

14. 13. An inkjet image recording method, which comprises forming an image using at least one inkjet ink according to any one of 1 to 12 above.

15. Using at least one ink-jet ink according to any one of the items 1 to 12,
An inkjet-recorded image, which is formed by performing inkjet-image recording.

The inventors of the present invention have made extensive studies as to improvement of the graininess, glossiness and light resistance of an output image using dye ink and pigment ink, and as a result, colored fine particles made of a resin containing dye and dye were coated. At least one kind of colored fine particles selected from colored fine particles in which the surface of a resin containing colored fine particles and a dye is further coated with a resin, and a pigment whose surface is coated with a water-insoluble and water-dispersible polymer layer By using an inkjet ink containing particles (hereinafter, also simply referred to as an ink) and setting the redispersion coefficient of the ink represented by the above formula (1) in the range of 0.5 to 5, the image characteristics are improved. It was found that the present invention was achieved by finding that a certain graininess, glossiness and light resistance can be achieved at the same time.

Conventionally, there is known an ink in which a dye ink is dissolved in a resin and dispersed in the ink in the form of fine particles. However, by using the dye as colored fine particles, the temperature is higher than that of a normal dye ink at room temperature. Although bleeding and water resistance under humidity can be improved, there was a drawback that the image bleeds when these inks are stored for a long time under high temperature and high humidity,
As a result of intensive studies by the present inventors, coexistence of colored fine particles having specific redispersibility and pigment particles makes it possible to achieve both image storability (light resistance) and image quality (granularity, glossiness). I found it.

Specifically, an image formed from an ink containing colored fine particles is fused at high temperature and high humidity for a long period of time so that the colored fine particles fuse with each other. When the particle dispersion state is destroyed, the ink solvent remaining in the surroundings,
It is considered that when it mixes with moisture in the air, liquefies, and the coloring material moves, bleeding occurs. It has been found that this phenomenon can be improved by coexisting colored fine particles having a specific redispersibility and pigment particles.

Although the process for improving bleeding by the constitution of the present invention is not clear, colored fine particles having an excellent redispersibility are difficult to fuse under high temperature and high humidity as a basic characteristic.
It is presumed that the above-mentioned characteristics are improved by further using the pigment particles together with the pigment particles so that the pigment particles are present between the colored particles and the fusion of the colored particles is further prevented.

Further, the pH of the ink, the surface tension, the amount of polyvalent metal ions, and the amount of the ink solvent are set within specific ranges.
It was found that the purpose and effect of the present invention can be further exerted by using a surfactant.

The details of the present invention will be described below. In the inkjet ink according to claim 1, at least one selected from colored fine particles made of a resin containing a dye, colored fine particles made of a resin coated with a dye, and colored fine particles having a surface of a resin containing a dye further coated with a resin. An inkjet ink containing colored particles of one kind and pigment particles, wherein the inkjet ink has a redispersion coefficient represented by the above formula (1) of 0.5 to 5, and the surface of the pigment particles. Is coated with a water-insoluble and water-dispersible polymer layer.

First, the colored fine particles composed of a dye and a resin will be described. The colored fine particles according to the present invention can be prepared by various methods. For example, a method of dissolving an oil-soluble dye in a monomer, emulsifying in water, then encapsulating the dye in a polymer by polymerization, a method of dissolving the polymer and the dye in an organic solvent, emulsifying in water, and then removing the organic solvent. , A method of adding porous polymer particles to a dye solution, and adsorbing and impregnating the dye with the particles, and the like.
A shelling method of coating those colored fine particles with a polymer can also be used.

The polymer shell is provided by adding a water-soluble polymer dispersant to the aqueous suspension of the core and adsorbing it, by gradually dropping the monomer and depositing it on the core surface at the same time as the polymerization, or by using an organic solvent. There is a method in which the polymer dissolved in is gradually dropped and adsorbed on the core surface simultaneously with precipitation. A method of forming the core shell in one step is also conceivable. For example, a method in which a core polymer and a dye are dissolved or dispersed in a shell polymer and suspended and polymerized in water, or emulsion polymerization is performed while gradually dropping the liquid into water containing an active agent micelle. There are ways. Alternatively, there is a method in which a dye is dissolved or dispersed in a monomer that can be a core and a monomer that can be a shell after polymerization, and suspension polymerization or emulsion polymerization is performed.

The colored fine particles according to the present invention are not particularly limited to shell-formed ones and shell-formed ones, but shell-formed ones are preferable in view of the effect of the invention. In that case, the amount of polymer used in the shell is preferably 5% by mass or more and 95% by mass or less of the total amount of polymer. When the amount is less than 5% by mass, the thickness of the shell is insufficient and a part of the core containing a large amount of dye is likely to appear on the particle surface. Also, if the shell polymer is too much,
It is easy to cause deterioration of the dye protection function of the core. More preferably, it is 10% by mass or more and 90% by mass or less.

The dye is 20% by mass based on the total amount of polymer.
It is preferably not less than 1000% by mass. When the amount of the dye is too small as compared with the polymer, the image density after ejection does not increase, and when the ratio of the dye is high, the polymer protecting ability cannot be sufficiently obtained.

(Evaluation of Core-Shell Formation) In the present invention, it is important to evaluate whether or not a core-shell structure is actually formed. In the present invention, the particle size of each particle is very small, 150 nm or less, so the analysis method is limited from the viewpoint of resolution. A transmission electron microscope (TEM), a time-of-flight secondary ion mass spectrometer (TOF-SIMS), or the like can be applied as an analysis method that meets such a purpose. TE
When observing the colored fine particles core-shelled by M,
The dispersion can be applied on a carbon support film, dried, and observed. Since the TEM observation image is usually monochrome, it is necessary to dye the colored fine particles in order to evaluate whether or not it is core-shelled. The colored fine particles of only the core are dyed, and the TEM observation is performed, and comparison is made with the one provided with the shell. Further, the fine particles provided with the shell and the fine particles not provided with the shell are mixed and dyed, and it is confirmed whether or not the ratio of the fine particles having different degrees of dyeing coincides with the presence or absence of the shell. In TOF-SIMS, it is confirmed that the dye in the vicinity of the surface is reduced by providing the shell on the particle surface as compared with the case where only the core is used. When the dye contains an element that is not contained in the core-shell polymer, it can be confirmed by using the element as a probe whether or not a shell having a small coloring material content is provided. In the absence of such elements, the dye content in the shell can be compared with that without the shell using a suitable dyeing agent. By embedding core-shell particles in an epoxy resin, making an ultrathin section with a microtome, and dyeing, core-shell formation can be observed more clearly. When the polymer or dye has an element that can serve as a probe, the composition of the core-shell and the amount of the dye distributed to the core and the shell can be estimated by TEM.

In order to obtain the required particle size, it is important to optimize the constituent conditions and select an appropriate emulsification method. The constitutional conditions differ depending on the dye and polymer used, but since it is a suspension in water, the shell polymer generally needs to be more hydrophilic than the core polymer. Further, the dye contained in the shell polymer is preferably less than that in the core polymer, and the dye also needs to be less hydrophilic than the shell polymer. Hydrophilicity and hydrophobicity can be estimated using, for example, the solubility parameter (SP). Regarding the solubility parameter, its value, measurement, and calculation method are POLYMER HANDBOOK 4th edition (JOH
N WILEY & SONS, INC. ) The description from page 675 is helpful.

The polymer used for the colored fine particles has a number average molecular weight of 500 to 100,000, especially 1.
000 to 30,000, the coating film strength after printing,
It is preferable in terms of its durability and suspension formability.

Various Tg values can be used for the polymer, but it is preferable to use at least one of the polymers having a Tg of 10 ° C. or higher.

In the present invention, all generally known polymers can be used, but particularly preferred polymers include a polymer containing an acetal group as a main functional group, a polymer containing a carbonic acid ester group and a hydroxyl group. And a polymer having an ester group, particularly the polymer constituting the outermost shell portion,
It preferably has a hydroxyl group. The above-mentioned polymer may have a substituent, and the substituent is linear,
It may have a branched or cyclic structure. Various polymers having the above-mentioned functional group are commercially available, but they can be synthesized by a conventional method. Also,
These copolymers can also be obtained by, for example, introducing an epoxy group into one polymer molecule, and then polycondensing it with another polymer, or performing graft polymerization using light or radiation.

Examples of the polymer containing acetal as a main functional group include polyvinyl butyral resin. For example, # 2000 manufactured by Denki Kagaku Kogyo Co., Ltd.
-L, # 3000-1, # 3000-2, # 3000-
4, # 3000-K, # 4000-1, # 4000-
2, # 5000-A, # 6000-C, # 6000-E
P, or BL-1, BL-1H manufactured by Sekisui Chemical Co., Ltd.
BL-2, BL-2H, BL-5, BL-10, BL-
S, BL-SH, BX-10, BX-L, BM-1, B
M-2, BM-5, BM-S, BM-SH, BH-3,
BH-6, BH-S, BX-1, BX-3, BX-5,
There are KS-10, KS-1, KS-3, KS-5 and the like.

Polyvinyl butyral resin is obtained as a derivative of PVA (polyvinyl alcohol), but the acetalization of the hydroxyl group of the original PVA is 80 mol at maximum.
%, Usually from 50 mol% to 80 mol%
It is a degree. It should be noted that the acetal referred to here is 1 in a narrow sense.
It does not refer to the 1-diethoxyethane group, but refers to compounds in general with orthoaldehyde. The hydroxyl group is not particularly defined, but in the polymer constituting the outermost shell portion, the hydroxyl group-containing monomer is preferably 5 to 50 mol%, more preferably 10 to 30 mol%.
Is. The content of acetyl groups is not particularly limited, but is preferably 10 mol% or less. A polymer containing acetal as a main functional group means at least 30 mol% of oxygen atoms contained in the polymer.
The above means that an acetal group is formed.

In addition, as a polymer containing acetal as a main functional group, Iupital series manufactured by Mitsubishi Engineering Plastics Co., Ltd. can be used.

Examples of the polymer containing carbonic acid ester as a main functional group include polycarbonate resins. For example, there are Iupilon series and Novarex series manufactured by Mitsubishi Engineering Plastics Co., Ltd. The Iupilon series is made from bisphenol A as a raw material, and various molecular weights can be used although the value varies depending on the measuring method. The Novarex series has a molecular weight of 20,000 and a glass transition point of 150.
A material having a temperature in the vicinity of ° C can be used, but the material is not limited to these.

The polymer containing a carbonic acid ester group as a main functional group means that at least 30 mol% or more of oxygen atoms contained in the polymer contribute to the formation of a carbonic acid ester group.

Examples of the polymer having a hydroxyl group as a main functional group include PVA. Although the solubility of PVA in organic solvents is low in many cases, the solubility of PVA in organic solvents increases if the saponification value is low. Highly water-soluble PVA can also be used by adding it to the aqueous phase, removing the organic solvent, and adsorbing it to the polymer suspension.

Commercially available PVA can be used, for example, Kuraray's Poval PVA-102 and PVA.
VA-117, PVA-CSA, PVA-617, PV
In addition to A-505, special grade PVA for sizing agents,
As PVA for hot melt molding and other functional polymers, K
L-506, C-118, R-1130, M-205,
MP-203, HL-12E, SK-5102, etc. can be used. The degree of saponification is generally 50 mol% or more, but it is 40 mol as in LM-10HD.
Even if it is about 1%, it is possible to use it.
Other than PVA, those having a hydroxyl group as a main functional group can be used, but those having at least 20 mol% or more of oxygen atoms contained in the polymer forming a hydroxyl group can be used.

Examples of the polymer containing an ester group as a main functional group include methacrylic resin. Asahi Kasei Delpet series 560F, 60N,
80N, LP-1, SR8500, SR6500, etc. can be used. The polymer containing an ester group as a main functional group means that at least 30 mol% or more of oxygen atoms contained in the polymer form an ester group.

One of these polymers is used or two of them are used.
You may mix and use 1 or more types. Further, other polymers and inorganic fillers may be contained as long as these polymers are contained in a mass ratio of 50% or more.

Although it is preferable to use a copolymer of these polymers, for example, a polymer containing a hydroxyl group,
As a method of copolymerizing various polymers, it can be obtained by reacting a hydroxyl group with a monomer having an epoxy group such as glycidyl methacrylate and then copolymerizing it with a methacrylic acid ester monomer by suspension polymerization.

In the dye ink of the present invention, the polymer used for the colored fine particles is 0.5 to 50 in the ink.
It is preferably blended in an amount of 0.5% by mass and 0.5 to 30% by mass.
It is more preferable that it is blended. If the blending amount of the above polymer is less than 0.5% by mass, the ability to protect the coloring material is insufficient, and if it exceeds 50% by mass, the storage stability of the suspension as an ink is lowered, or the nozzle tip portion is deteriorated. Since there is a case where clogging of the printer head may occur due to thickening of the ink and aggregation of the suspension due to the evaporation of the ink, it is preferably within the above range.

On the other hand, the dye is preferably blended in the dye ink in an amount of 1 to 30% by mass, more preferably 1.5 to 25% by mass. If the compounding amount of the above dye is less than 1% by mass, the printing density is insufficient, and 30% by mass
When it exceeds, the stability of the suspension with time is deteriorated and the particle size tends to increase due to aggregation or the like. Therefore, it is preferably within the above range.

The dye ink of the present invention comprises a suspension of a polymer containing water as a medium and encapsulating the above coloring material.
In the suspension, various conventionally known additives, for example, wetting agents such as polyhydric alcohols, dispersants, antifoaming agents such as silicone, antifungal agents such as chloromethylphenol, and / or chelates such as EDTA. An agent, or an oxygen absorbent such as sulfite may be contained.

Here, examples of the wetting agent include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, diethylene glycol diethyl ether, diethylene glycol mono-n-butyl ether, ethylene glycol monomethyl ether, ethylene. Such as glycol monoethyl ether, ethylene glycol monobutyl ether, methyl carbitol, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, diethyl carbitol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, etc. Polyhydric alcohol and its ether, ace Or one or more of nitrogen-containing compounds such as salts, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, triethanolamine, formamide and dimethylformamide, and dimethyl sulfoxide. be able to. The amount of these wetting agents added is not particularly limited, but it is preferably 0.1 to 50% by mass, and more preferably 0.1 to 30% by mass in the ink.

The dispersant is not particularly limited, but having an HLB value of 8 to 18 provides the effect as a dispersant and suppresses the increase in the particle size of the suspension. It is preferable from a certain point.

Commercially available products can also be used as the dispersant. Examples of such a commercially available product include dispersants DEMOL SNB, MS, N, SSL, ST, P manufactured by Kao Corporation.
(Product name).

The blending amount of the dispersant is not particularly limited, but 0.01 to 10% by mass is preferably blended in the ink of the present invention. If the compounding amount of the compound is less than 0.01% by mass, it is difficult to reduce the particle size of the suspension, and if it exceeds 10% by mass, the particle size of the suspension is increased or the suspension stability is lowered to cause gelation. Therefore, it is preferable that the content is within the above range.

The defoaming agent is not particularly limited, and commercially available products can be used. Examples of such commercially available products include Shin-Etsu Silicone KF96, 66,
69, KS68, 604, 607A, 602, 603,
KM73, 73A, 73E, 72, 72A, 72C, 7
2F, 82F, 70, 71, 75, 80, 83A, 8
5, 89, 90, 68-1F, 68-2F (trade name) and the like. The compounding amount of these compounds is not particularly limited, but in the colored fine particle-containing aqueous ink of the present invention, 0.00
It is preferably blended in an amount of 1 to 2% by mass. If the compounding amount of the compound is less than 0.001% by mass, bubbles are likely to be generated during ink preparation, and it is difficult to remove small bubbles in the ink.
If it exceeds 2% by mass, the generation of bubbles can be suppressed, but at the time of printing, repellency may occur in the ink and the print quality may deteriorate. Therefore, it is preferably within the above range.

Next, the method for producing the dye ink of the present invention will be described. The dye ink of the present invention can be manufactured by various emulsification methods.

Various methods can be used as the emulsification method. Examples of these are summarized, for example, in the description on page 86 of “Progress of Functional Emulsifiers / Emulsification Technologies and Their Application and Development”. In the present invention, it is particularly preferable to use an emulsifying / dispersing device using ultrasonic waves, high-speed rotary shearing, and high pressure.

Two types of so-called batch type and continuous type can be used for the ultrasonic dispersion. The batch type is
It is suitable for preparing a relatively small amount of sample, and the continuous method is suitable for preparing a large amount of sample. In the continuous system, for example, UH-60
It is possible to use a device such as 0SR (manufactured by SMT Co., Ltd.). In the case of such a continuous system, the irradiation time of ultrasonic waves can be obtained by the formula: volume of dispersion chamber / flow velocity × number of circulations. When there are a plurality of ultrasonic irradiation devices, the total irradiation time can be calculated. The ultrasonic irradiation time is actually required to be 3 seconds or more, and if the emulsification is completed within that time, the ultrasonic emulsification dispersion device is not required. Further, if it is necessary for 10000 seconds or more, the load of the process is heavy, and it is necessary to shorten the emulsification / dispersion time by reselection of the emulsifier in practice. Therefore, 10,000 seconds or more is not necessary. More preferably, 10 seconds or more, 200
Within 0 seconds.

Examples of the emulsification / dispersion device using high-speed rotary shearing include a disper mixer as described on pages 255-256 of “Advancement of functional emulsifier / emulsification technology and its application development”, and page 251. A homomixer as described above, an ultramixer as described on page 256, or the like can be used. These types can be used properly depending on the liquid viscosity at the time of emulsion dispersion. In these emulsifying dispersers using high-speed rotary shearing, the rotation speed of the stirring blade is important. Since the clearance with the stator is usually about 0.5 mm and cannot be extremely narrowed, the shearing force mainly depends on the peripheral speed of the stirring blade. When the peripheral speed is 5 m / sec or more and 150 m / sec or less, it can be used in the emulsification / dispersion of the present invention. This is because when the peripheral speed is slow, it is often impossible to reduce the particle size even if the emulsification time is extended, and it is necessary to extremely improve the performance of the motor in order to achieve 150 m / sec. More preferably, it is 20 to 100 m / sec.

For emulsification and dispersion by high pressure, LAB2000
(Manufactured by SMT) or the like can be used, but its emulsification / dispersion ability depends on the pressure applied to the sample. Pressure is
It is preferably 10 MPa or more and 500 MPa or less. In addition, the desired particle size can be obtained by emulsifying and dispersing several times as necessary. If the pressure is too low, the desired particle size cannot be achieved in many cases, no matter how many times emulsification and dispersion are performed, and in order to set the pressure to 500 MPa, a large load is applied to the device, which is not practical. More preferably, 50
It is not less than MPa and not more than 200 MPa.

These emulsifying / dispersing devices may be used alone, but may be used in combination as required. A colloid mill, a flow jet mixer, etc., alone cannot achieve the object of the present invention, but by combining with the above-mentioned device, the effect of the present invention can be enhanced by enabling emulsification / dispersion in a single time. .

Further, the ink of the present invention can be produced by so-called phase inversion emulsification, in addition to using the above apparatus.

Here, in the phase inversion emulsification, the above-mentioned polymer is dissolved in an organic solvent such as ester or ketone together with the above-mentioned dye, a neutralizing agent is added as necessary to ionize the carboxyl group in the polymer, and then the After adding the aqueous phase, the organic solvent is distilled off to invert the phase to an aqueous system.

After completion of the phase inversion, the system is heated under reduced pressure to remove the above ester and ketone solvents and a predetermined amount of water to obtain the colored fine particles of the present invention having a desired concentration. A water-based ink containing ink is obtained.

As the dye that can be used in the present invention,
There is no particular limitation, and examples thereof include oily dyes, disperse dyes, direct dyes, acid dyes, and basic dyes. In the present invention, it is preferable to use oily dyes. As the hue, yellow, magenta, cyan, black, blue, green and red are preferably used, and yellow, magenta, cyan and black dyes are particularly preferable. The oil-soluble dyes also include dyes that exhibit oil-solubility by forming a salt of a water-soluble dye with a long-chain base.
The oil dye is not limited to the following,
As a particularly preferable specific example, for example, Valifast Yellow 4 manufactured by Orient Chemical Industry Co., Ltd.
120, Valifast Yellow 3150,
Valifast Yellow 3108, Vali
fast Yellow 2310N, Valifas
t Yellow 1101, Valifast Re
d 3320, Valifast Red 3304,
Valifast Red 1306, Valifas
t Blue 2610, Valifast Blue
2606, Valifast Blue 1603,
Oil Yellow GG-S, Oil Yellow
3G, Oil Yellow 129, Oil Ye
low 107, Oil Yellow 105, Oi
l Scarlet 308, Oil Red RR,
Oil Red OG, Oil Red 5B, Oil
Pink 312, Oil Blue BOS, Oil
Blue 613, Oil Blue 2N, Oil
Black BY, Oil Black BS, Oi
l Black 860, Oil Black 597
0, Oil Black 5906, Oil Black
k 5905, Kayaset manufactured by Nippon Kayaku Co., Ltd.
Yellow SF-G, Kayaset Yellow
w K-CL, Kayaset Yellow GN,
Kayaset Yellow AG, Kayase
t Yellow 2G, Kayaset Red S
F-4G, Kayase Red K-BL, Kay
Aset Red A-BR, KayasetMage
nta312, Kayase Blue K-FL,
Arimoto Chemical Industry Co., Ltd. FS Yellow 101
5, FS Magenta 1404, FS Cyan
1522, FS Blue 1504, C.I. I. So
lvent Yellow 88, Solvent Y
ellow 83, Solvent Yellow 8
2, Solvent Yellow 79, Solve
nt Yellow 56, Solvent Yell
ow 29, Solvent Yellow 19, S
solvent Yellow 16, Solvent
Yellow 14, Solvent Yellow
04, Solvent Yellow 03, Solv
ent Yellow 02, Solvent Yel
low 01, C.I. I. Solvent Red 84:
1, C.I. I. Solvent Red 84, C.I. I.
SolventRed 218, C.I. I. Solven
t Red 132, C.I. I. Solvent Red
73, C.I. I. Solvent Red 72, C.I.
I. Solvent Red 51, C.I. I. Solv
ent Red 43, C.I. I. Solvent Re
d 27, C.I. I. Solvent Red 24, S
solvent Red 18, Solvent Red
01, SolventBlue 70, Solven
t Blue 67, Solvent Blue 44,
Solvent Blue 40, Solvent B
lue 35, Solvent Blue 11, S
solvent Blue 02, Solvent Bl
ue 01, Solvent Black 43, C.I.
I. Solvent Black 70, C.I. I. So
lvent Black 34, C.I. I. Solven
t Black 29, C.I. I. Solvent Bl
ack 27, C.I. I. Solvent Black
22, C.I. I. Solvent Black 7, C.I.
I. Solvent Black 3, C.I. I. Sol
Vent Violet 3, C.I. I. Solven
t Green 3 and 7 and the like.

In addition, JP-A-9-277693 and 10
Metal complex dyes as shown in Nos. -20559 and 10-30061 are also preferably used, and a preferable structure is represented by the following general formula (1).

In the general formula (1) M (Dye) _l (A) _m , M represents a metal ion, and Dye represents a dye capable of forming a coordinate bond with a metal. A represents a ligand other than the dye, 1 represents 1 to 3 and m represents 0, 1, 2, 3. When m is 0, 1 represents 2 or 3, and in that case, Dye may be the same or different. Examples of the metal ion represented by M include Al, Co, Cr, Cu, Fe, Mn, Mo and N.
Examples include ions of i, Sn, Ti, Pt, Pd, Zr, and Zn. Ni, Cu, Cr, from the color tone and various durability,
Ions of Co, Zn and Fe are particularly preferable. More preferably, it is Ni ion.

Various dye structures are conceivable as the dye represented by Dye and capable of forming a coordinate bond with the metal, but a conjugated methine dye, an azomethine dye, and a dye having a coordination group in the azo dye skeleton are preferable.

The disperse dye is not limited to the following, but a particularly preferred specific example is C.I. I. Disperse Yellow 5, 42, 54, 64, 79, 8
2, 83, 93, 99, 100, 119, 122, 12
4, 126, 160, 184: 1, 186, 198, 1
99, 204, 224 and 237; C.I. I. Disperse Orange 13, 29, 31: 1, 33, 49, 54,
55, 66, 73, 118, 119 and 163;
I. Disperse Red 54, 60, 72, 73, 8
6, 88, 91, 92, 93, 111, 126, 12
7, 134, 135, 143, 145, 152, 15
3, 154, 159, 164, 167: 1, 177, 1
81, 204, 206, 207, 221, 239, 24
0, 258, 277, 278, 283, 311, 32
3, 343, 348, 356 and 362; I. Disperse Violet 33; C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143,
148, 154, 158, 165, 165: 1, 16
5: 2, 176, 183, 185, 197, 198, 2
01, 214, 224, 225, 257, 266, 26
7, 287, 354, 358, 365 and 368; and C.I. I. Examples include Disperse Green 6: 1 and 9.

Further, one feature of the present invention is to use pigment particles whose surface is coated with a water-insoluble and water-dispersible polymer layer together with the colored fine particles.

As the pigment which can be used in the present invention,
Known colored organic or colored inorganic pigments can be used. For example, azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthaloni pigments, etc. Examples include polycyclic pigments, dye lakes such as basic dye type lakes and acid dye type lakes, organic pigments such as nitro pigments, nitroso pigments, aniline black and daylight fluorescent pigments, and inorganic pigments such as carbon black. However, the present invention is not limited to these.

Specific organic pigments are exemplified below. Examples of magenta or red pigments include C.I. I.
Pigment Red 2, C.I. I. Pigment Red 3,
C. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16, C.I.
I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 57: 1,
C. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 139, C.I.
I. Pigment Red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166, C.I. I.
Pigment Red 177, C.I. I. Pigment Red 1
78, C.I. I. Pigment Red 222 and the like.

Examples of pigments for orange or yellow include C.I. I. Pigment Orange 31, C.I.
I. Pigment Orange 43, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I.
Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 9
3, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 128, C.I. I. Pigment Yellow 13
8 etc. are mentioned.

As the pigment for green or cyan,
For example, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 1
5: 3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

As the black pigment, for example, C.I. I. Pigment Black 1, C.I. I. Pigment Black 6, C.I. I. Pigment Black 7 and the like.

In the present invention, the pigment particles whose surface is coated with a water-insoluble and water-dispersible polymer layer are, for example, a polymer compound (also referred to as a polymer) having the pigment particle as a core and the surface as a shell. Particles coated with, or
Examples thereof include particles in which a polymer compound particle containing a pigment particle is used as a core, and the surface thereof is used as a shell to be coated with a polymer compound.

The pigment particles whose surface is coated with the polymer compound according to the present invention can be prepared by various methods described below.

For example, a method of dispersing pigment particles described in JP-A-8-71405 with a polymer compound, dissolving the polymer compound in an organic solvent, and then phase inversion emulsifying in water, Journal of Coloring Materials, 70, 503 (1997), the method of polymerizing after adsorbing a monomer on the surface of pigment particles, Journal of Coloring Materials, 69, 743 (1996) and 72, 748.
The method of introducing a polymerization initiator to the surface of the pigment particle described in (1999) and then polymerizing it with a monomer can be mentioned.

In each of the above-mentioned methods, the polymer compound which can be used in the method of dissolving the polymer compound in which the pigment is dispersed in an organic solvent and then subjecting the polymer to phase inversion emulsification in water is used. , -COOH, -SO ₃ H) has, is soluble in an organic solvent in the acid form, a polymer compound soluble neutralized hydrophilic increases with a basic substance such as an alkali or amine. Specific examples thereof include acrylic resin, styrene resin, polyester resin, epoxy resin, polyurethane resin, and the like, and acrylic resin and styrene resin are preferable.

As a method of polymerizing after adsorbing the monomer on the surface of the pigment particle, the pigment, the polymer containing the polar group and the hydrophobic monomer are added to the water-containing liquid, and the monomer is adsorbed for a certain time, and then the polymerization is started It can be obtained by adding an agent and polymerizing for a certain period of time.

Examples of polar group-containing monomers that can be used in the above method include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid,
Monobutyl itaconate, monobutyl maleate, acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl methacrylate, etc. Can be mentioned.

As the hydrophobic monomer, for example, various styrene-based monomers (aromatic vinyl monomers) such as styrene, vinyltoluene, 2-methylstyrene, t-butylstyrene or chlorostyrene; methyl acrylate, Ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-acrylate
Various acrylates such as hexyl, 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate or dodecyl acrylate; methyl methacrylate, propyl methacrylate, n-methacrylate
Various methacrylates such as butyl, isobutyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, decyl methacrylate or dodecyl methacrylate; hydroxy acrylate Various hydroxyl group-containing monomers such as ethyl or hydroxypropyl methacrylate; or N
Various types of N-, such as methylol (meth) acrylamide or N-butoxymethyl (meth) acrylamide
Substituted (meth) acrylic monomers are included.

As the polymerization initiator which can be used,
There is no particular limitation, and for example, benzoyl peroxide, di-t-
Butyl peroxide, cumene hydroperoxide, t-
There may be mentioned various peroxides such as butyl peroxide or 2-ethylhexanoate; or various azo compounds such as azobisisobutyronitrile or azobisisovaleronitrile.

As a method of introducing a polymerization initiator to the surface of the pigment particles and then polymerizing it with the monomer, a functional group (eg, amino group or hydroxyl group) of the pigment is chemically reacted with a peroxide group such as a peroxycarbonyl group. And a method of introducing a group that initiates polymerization from the carboxyl group by generating a carboxyl group on the pigment surface with an oxidizing agent such as hypochlorous acid. A polymer-coated pigment can be obtained by polymerizing the above-mentioned hydrophobic monomer and polar group-containing monomer with the pigment having a polymerization initiation group on the surface obtained by these methods.

In the present invention, the coating amount of the polymer compound with respect to the pigment is 1% or more and 100% or less, preferably 5% or more and 50% or less.

In the invention according to claim 1, the ink-jet ink is characterized in that the redispersion coefficient represented by the formula (1) of the coloring fine particles and the pigment particles in the aqueous solvent is 0.5 to 5. one of.

The redispersion coefficient as used in the present invention is a scale showing the dispersion stability and cohesiveness of the colored fine particles and the pigment particles,
As represented by the above formula (1), it is represented by the ratio of the volume average particle size of the colored fine particles and the pigment particles after redispersion to the volume average particle size of the colored fine particles and pigment particles before redispersion. The volume average particle diameter in the present invention is a value measured by the secondary particle diameter.

More specifically, the volume average particle size of the colored fine particles and pigment particles before redispersion represents the secondary particle size of the prepared ink, and the volume average particle size of the colored fine particles and pigment particles after redispersion Is a secondary particle diameter of the colored fine particles and the pigment particles after the ink is dried, and then the dried colored fine particles and the pigment particles are added to water or an ink medium such as an organic solvent, and peptized. The smaller the redispersion coefficient represented by the formula (1), the better the peptizing property and dispersibility, and the less the number of aggregates generated. The redispersion coefficient of 1 indicates that the secondary particle diameter changes before and after redispersion. Means no.

As a concrete measuring method, 1 m of ink is used.
After being sampled and spread evenly on a washed petri dish, it is left at room temperature and normal humidity for 1 week and dried. Then, 1 ml of water was added to the dried product, and using a glass rod,
The mixture is stirred for 2 minutes and redispersed, and the volume average particle diameters of the colored fine particles and the pigment particles before and after drying are measured by the following method.

The volume average particle diameter can be measured by a commercially available particle size measuring device using, for example, a light scattering method, an electrophoresis method, a laser Doppler method, etc. , Shimadzu laser diffraction particle size analyzer SLAD1100, particle size analyzer (HOR
IBA LA-920), Zetasizer 1000 manufactured by Malvern Instruments Ltd., and the like.

The present invention is characterized by a redispersion coefficient of 0.5 to 5, preferably 0.7 to 3, and more preferably 0.8 to 2.

In the present invention, the means for adjusting the redispersion coefficient to the range defined above is not particularly limited, but for example, the pigment particles according to the present invention whose surface is coated with a polymer compound are used. Coating the colored fine particles or the pigment particle surface with a polymer compound, optimizing the type and addition amount of the surfactant, controlling the secondary particle size distribution of the pigment particles, pigment dispersing means and its dispersing conditions A desired redispersion degree can be obtained by appropriately selecting or combining various means such as optimizing.

Examples of the dispersing device that can be used in the present invention include various dispersing devices such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill and a paint shaker. I can raise the opportunity.

The invention according to claim 2 is characterized in that the pH of the ink-jet ink defined in claim 1 is 7.0 or more, but it is preferably 8.0 to 10.0. Examples of the pH adjuster used in the aqueous medium used in the pigment ink of the present invention include various organic amines such as monoethanolamine, diethanolamine and triethanolamine, sodium hydroxide, lithium hydroxide,
Examples thereof include inorganic alkali agents such as alkali metal hydroxides such as potassium hydroxide, organic acids, and mineral acids.

Further, in the invention according to claim 3, the invention according to claim 1
Alternatively, the surface tension of the inkjet ink defined by 2 is 25 to 45 mN / m, and preferably 30 to 40 mN / m. As a means for adjusting the surface tension of the pigment ink of the present invention, it is preferable to appropriately adjust the type and amount of addition using various surfactants described later.

The invention according to claim 4 is characterized in that the colored fine particles have a secondary volume average particle diameter of 10 to 150 nm, preferably 20 to 120 nm, more preferably 20 to 80 nm, and In the invention according to claim 5, the secondary volume average particle diameter of the pigment particles is 10 to 150 n.
m is a feature, and preferably 10 to 100 n
m, more preferably 20 to 70 nm, particularly preferably 20 to 50 nm, and it is preferable that the effect of the present invention can be exerted at all by making each particle have a volume average particle diameter defined in the present invention. .

The secondary volume average particle diameter of the colored fine particles and the pigment particles can be determined by the same method as described above for the redispersion coefficient.

The invention according to claim 6 is characterized in that the polyvalent metal ion content of the ink is 5 ppm or less, preferably 0.1 to 3 ppm, particularly preferably 0.1 to 1 ppm. is there. By setting the content of the polyvalent metal ion in the ink to the amount defined above, an ink having high dispersion stability can be obtained.

The polyvalent metal ion in the present invention means, for example, Fe ³⁺ , Sr ²⁺ , Mg ²⁺ , Ca ²⁺ , Zn ²⁺ , Z.
^Examples thereof include r ²⁺ , Ni ²⁺ and Al ³⁺ , which are contained as sulfates, chlorides, nitrates, acetates, organic ammonium salts, EDTA salts and the like.

The invention according to claim 7 is characterized in that the ink solvent content is 5 to 70% by mass, preferably 10 to 60% by mass, particularly preferably 20 to 50% by mass.

The ink solvent used in the present invention is not particularly limited, but it is preferable to use a compound represented by the following general formula (1). General formula (1) AB In formula, A represents a group containing a hydrophilic substituent, and B represents a hydrophobic group.

The group represented by A is a group containing a hydrophilic substituent, and examples of the hydrophilic substituent include a hydroxy group, a carboxyl group, a sulfoxide group, a sulfone group, a sulfonic acid group and 2-keto-1. -Pyrrolidinyl group and the like.
Of these, a hydroxy group is preferable.

B represents a hydrophobic group, preferably an aliphatic or aromatic hydrocarbon group having 3 to 10 carbon atoms.
Further, B is preferably an aliphatic group having 4 to 8 carbon atoms.

The compound represented by the general formula (1) has a structure similar to that of a general surfactant. A general surfactant has a characteristic of forming micelles in an aqueous solution at a low concentration.

The compound represented by the general formula (1) preferably does not have such a micelle forming ability. This is because, when it has a micelle forming ability, it has a drawback that the viscosity of the ink remarkably increases when the concentration exceeds 1% because the interaction between molecules is strong.

Among the compounds represented by the general formula (1), preferred examples include polyhydric alcohol ether derivatives and aliphatic 1,2-diols having 4 to 8 carbon atoms, such as ethylene glycol monobutyl ether. (Butyl cellosolve), diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monophenyl ether, 1,
A compound selected from 2-hexanediol and 1,2-pentanediol is more preferable. More preferred is triethylene glycol monobutyl ether or 1,2-hexanediol.

As the other ink solvent which can be used in the present invention, a water-soluble organic solvent is preferable, and specifically, alcohols (eg, methanol, ethanol,
Propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc., polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol) , Dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (for example, ethylene glycol monomethyl ether,
Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, tri Ethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, triethylene glycol dimethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol dimethyl ether, etc.), amines For example, ethanolamine, diethanolamine, triethanolamine, N- methyldiethanolamine, N- ethyldiethanolamine, morpholine, N- ethylmorpholine, ethylenediamine,
Diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.), amides (eg, formamide, N, N-)
Dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-). Examples thereof include imidazolidinone), sulfoxides (eg dimethyl sulfoxide), sulfones (eg sulfolane etc.), sulfonates (eg 1-butanesulfonic acid sodium salt etc.), urea, acetonitrile, acetone and the like.

In the ink of the present invention, an anionic surfactant is used in the invention of claim 8, a nonionic surfactant is used in the invention of claim 9, and a cationic surfactant is used in the invention of claim 10. The invention according to claim 11 is characterized in that it contains an anionic surfactant and a nonionic surfactant.

Each surfactant which can be used in the present invention is not particularly limited, but examples thereof include anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates and fatty acid salts, and polyoxyethylene alkyl ethers. , Nonionic surfactants such as polyoxyethylene alkyl allyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. To be In particular, an anionic surfactant and a nonionic surfactant can be preferably used.

Further, in the present invention, a high molecular surface active agent can also be used. For example, styrene-acrylic acid-alkyl acrylate copolymer, styrene-acrylic acid copolymer, styrene-maleic acid-acrylic. Acid alkyl ester copolymer, styrene-maleic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-maleic acid half ester copolymer, vinylnaphthalene-acrylic Examples thereof include acid copolymers and vinylnaphthalene-maleic acid copolymers.

The invention according to claim 12 is characterized in that the ink contains a water-soluble polymer or a water-insoluble polymer dispersion liquid.

A natural polymer is a preferable example of the water-soluble polymer, and specific examples thereof include glue and
Proteins such as gelatin, casein, or albumin, natural gums such as gum arabic, or gum tragacanth, glucosides such as savonine, alginic acid and propylene glycol alginate, triethanolamine alginate, or alginate derivatives such as ammonium alginate, methylcellulose, Examples thereof include cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, or ethyl hydroxyl cellulose.

Further, as a preferable example of the water-soluble polymer, a synthetic polymer can be mentioned. Polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers. Acrylic resins such as vinyl acetate-acrylic acid ester copolymers or acrylic acid-acrylic acid ester copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid Ester copolymer, styrene-
Styrene acrylic acid resin such as α-methylstyrene-acrylic acid copolymer or styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer Copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene-maleic acid copolymer, and vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinylethylene copolymer, vinyl acetate-maleic acid ester copolymer, acetic acid Examples thereof include vinyl acetate-based copolymers such as vinyl-crotonic acid copolymers and vinyl acetate-acrylic acid copolymers and salts thereof. Among these, polyvinylpyrrolidones are particularly preferable.

The molecular weight of the water-soluble polymer is preferably 1,000 or more and 200,000 or less. Furthermore, 3,000 or more and 20,000 or less are more preferable. When it is less than 1,000, the effect of suppressing the growth and aggregation of pigment particles is reduced, and when it exceeds 200,000, problems such as viscosity increase and poor dissolution tend to occur.

The amount of the water-soluble polymer added is 1 with respect to the pigment.
It is preferably 0% by mass or more and 1,000% by mass or less. Furthermore, 50 mass% or more and 200 mass% or less are more preferable.
If it is less than 10% by mass, the effect of suppressing the growth and aggregation of the pigment particles is reduced, and if it exceeds 1000% by mass, problems such as viscosity increase and poor dissolution tend to occur.

Further, as a water-insoluble polymer dispersion liquid (hereinafter, also referred to as latex) which can be used in the present invention,
Although not particularly limited, for example, styrene-butadiene copolymer, polystyrene, acrylonitrile-butadiene copolymer, acrylic ester copolymer, polyurethane,
Examples thereof include silicone-acrylic copolymers and latices such as acrylic modified fluorinated grease. Latex, even if the polymer particles are dispersed using an emulsifier,
It may also be dispersed without using an emulsifier. A surfactant is often used as an emulsifier, but a polymer having a water-soluble group such as a sulfonic acid group or a carboxylic acid group (for example, a polymer having a solubilizing group graft-bonded thereto or a monomer having a solubilizing group It is also preferable to use a polymer obtained from a monomer and a monomer having an insoluble portion.

In the ink of the present invention, it is particularly preferable to use soap-free latex. Soap-free latex is a latex that does not use an emulsifier, and a polymer having a water-soluble group such as a sulfonic acid group and a carboxylic acid group (for example, a polymer having a solubilizing group graft-bonded thereto, a solubilizing group Polymer obtained from a monomer having an insoluble portion and a monomer having an insoluble portion) is used as an emulsifier.

In recent years, as polymer particles of latex, in addition to latex in which polymer particles having a uniform particle size are dispersed, core particles having different compositions at the central part and the outer edge part
Although there is a latex in which shell-type polymer particles are dispersed, this type of latex can also be preferably used.

In the ink of the present invention, the average particle size of the polymer particles in the latex is 10 nm or more and 300 nm or less, and more preferably 10 nm or more and 100 nm or less. If the average particle size of the latex exceeds 300 nm, the glossiness of the image deteriorates, and if it is less than 10 nm, the water resistance and scratch resistance become insufficient. The average particle size of the polymer particles in the latex can be determined by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, or a laser Doppler method.

In the ink of the present invention, the latex is 0.1% by mass based on the total mass of the ink as a solid content addition amount.
As described above, it is added so as to be 20% by mass or less, but the solid content of the latex is 0.5% by mass or more and 10% by mass.
The following is particularly preferable. If the solid content of the latex is less than 0.1% by mass, it is difficult to exert a sufficient effect on water resistance, and if it exceeds 20% by mass, the viscosity of the ink increases with time and the particle size of the pigment dispersion is increased. In many cases, problems occur in terms of ink storability, such as an increase in ink liquor.

In the ink of the present invention, in addition to the above description, if necessary, the ejection stability, the compatibility with the print head or the ink cartridge, the storage stability, the image storability, and other purposes for improving various performances are satisfied. It is possible to appropriately select and use various known additives, for example, a viscosity modifier, a specific resistance modifier, a film forming agent, an ultraviolet absorber, an antioxidant, an anti-fading agent, an antibacterial agent, and an anticorrosive agent. For example, liquid paraffin, dioctyl phthalate, tricresyl phosphate, oil droplet fine particles such as silicone oil, and JP-A-57-74.
193, 57-87988 and 62-2614.
UV absorbers described in JP-A-76-74192.
No. 57-89789, No. 60-72785, No. 61-146591, No. 1-95091 and No. 3-13376, and anti-fading agents, No. 59-42993, 59-52689, 62
Examples thereof include fluorescent whitening agents described in JP-A-280069, JP-A-61-242871 and JP-A-4-219266.

The recording medium used in the present invention includes plain paper, coated paper, swelling type inkjet recording paper provided with an ink receiving layer which absorbs and swells an ink liquid, and voids having a porous ink receiving layer. Type inkjet recording paper,
Further, a substrate using a resin support such as a polyethylene terephthalate film can be used instead of the base paper, but it is preferable to use a porous inkjet recording medium as the recording medium, and this combination provides the best effect of the present invention. Can be demonstrated.

As the porous ink jet recording medium,
Specifically, mention may be made of void-type inkjet recording paper or void-type inkjet film, which are recording media provided with a void layer having an ink absorbing ability, and the void layer is mainly hydrophilic. It is formed by soft agglomeration of the binder and the inorganic fine particles.

Various methods for forming a void layer are known as a method for forming voids in a film. For example, a uniform coating solution containing two or more kinds of polymers is coated on a support and dried in a drying process. A method of phase-separating these polymers with each other to form voids, a coating liquid containing solid fine particles and a hydrophilic or hydrophobic binder is applied on a support, and after drying,
A method of immersing an inkjet recording paper in water or a liquid containing a suitable organic solvent to dissolve solid fine particles to form voids, a coating liquid containing a compound having a property of foaming during film formation, and a drying process. A method of foaming this compound to form voids in the film, a method of applying a coating liquid containing porous solid fine particles and a hydrophilic binder onto a support to form voids in the porous fine particles or between the fine particles. ,
A method of forming voids between solid fine particles by applying a coating liquid containing solid fine particles and / or fine particle oil droplets and a hydrophilic binder having a volume equal to or more than the hydrophilic binder to a solid fine particle. However, when using the ink of the present invention, good results are obtained even if they are provided by any method.

The ink jet head that can be used in the ink jet image recording method of the present invention may be either an on-demand type or a continuous type.
In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type,
Bender type, piston type, shear mode type, shared wall type, etc., electric-heat conversion method (for example, thermal inkjet type, bubble jet (registered trademark) type, etc.), electrostatic attraction method (for example, electric field control type, slit) Specific examples include a jet type) and a discharge method (for example, a spark jet type).
Either ejection method may be used.

[0133]

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example 1 << Preparation of Colored Fine Particles (Dye) >> Magenta colored fine particles 1 to 7 shown in Table 1 were prepared. The following is an example of preparation.

(Preparation Example 1: Preparation of magenta colored fine particles 6) 5.0 g of polyvinyl butyral (BL made by Sekisui Chemical Co., Ltd.
-10, average degree of polymerization 250), 5.0 g of magenta dye 2 and 100 g of ethyl acetate were placed in a separable flask, the inside of the flask was replaced with nitrogen gas, and the mixture was stirred to completely remove the polyvinyl butyral and magenta dyes. Dissolved in. Next, 90 g of an aqueous solution containing 1.0 g of sodium lauryl sulfate was dropped and stirred, and then an ultrasonic disperser (U
H-150 type, manufactured by SMT Co., Ltd.)
Emulsified for 00 seconds. Then, ethyl acetate was removed under reduced pressure to obtain a core type colored fine particle dispersion liquid impregnated with a magenta dye.

To this, 0.1 g of potassium persulfate was added and dissolved, and after heating with a heater to 70 ° C., 2.
A mixed solution of 50 g of styrene, 1.25 g of 2-ethylhexyl acrylate and 1.25 g of 2-hydroxyethyl methacrylate was added dropwise for 7 hours to obtain a dispersion liquid of magenta core-shell type colored fine particles 6. The average particle size of the colored fine particles 6 was 64 nm. The average particle diameter in the present invention is a volume average particle diameter measured by using a laser particle size analysis system manufactured by Otsuka Electronics.

(Preparation of Other Colored Fine Particles) Magenta colored fine particles other than those described above were also prepared in the composition shown in Table 1 according to the above preparation example. The colored fine particles 1
The core polymers used in the preparations of the above
001-19880 and 2001-13960
It was prepared according to the method described in Publication No.

Table 1 shows the characteristics of each colored fine particle obtained as described above. The secondary volume average particle diameter of the colored fine particles shown in Table 1 was measured by the following method.

<Measurement of Average Particle Diameter of Colored Fine Particles> Each colored fine particle dispersion was mixed with SA-5 (Perex OT-P) of 0.
After diluting 1000 times with a 1% aqueous solution, it was measured using Zetasizer 1000 manufactured by Malvern.

The details of the abbreviations of the compounds shown in Table 1 are as follows.

[0141]

[Chemical 1]

Dye 4: Orazole Red G (Metal complex of red azo dye manufactured by Ciba Geigy) P-1: Styrene / lauryl methacrylate / 2-hydroxyethyl acrylate / polyethylene glycol methacrylate / methacrylic acid / silicone macromer /
Ethyl mercaptan = 30/25/15/10/10 /
10/1 (methacrylic acid was neutralized with potassium hydroxide after the dye was dissolved) P-2: n-butoxymethyl acrylamide / ethylene glycol dimethacrylate = 99/1 PVB: polyvinyl butyral PMMA: polymethyl methacrylate HEMA: 2- Hydroxyethyl methacrylate P-3: Styrene / 2-hydroxyethyl methacrylate = 75/25 P-4: Styrene / 2-ethylhexyl acrylate /
2-hydroxyethyl methacrylate = 50/25/2
5 P-5: methyl methacrylate / 2-ethylhexyl acrylate / 2-hydroxyethyl methacrylate = 5
0/25/25 SA-1: Sodium dodecylbenzenesulfonate SA-2: New Frontier S510 (Daiichi Kogyo Seiyaku Co., Ltd.) SA-3: Emulgen LS-110 (Kao, Nonionic surfactant)

[0143]

[Table 1]

<< Preparation of Pigment Particles Coated with Polymer Layer >> (Preparation of Pigment Particle Dispersion Liquid 101: Pigment Dispersion Method A) Using Fastgen Super Magenta RTS (manufactured by Dainippon Ink and Chemicals) as a pigment 10-1200
According to Production Example 3 described in Japanese Patent Publication No. 65-65, magenta pigment particle dispersion liquid 10 in which pigment particle surfaces are coated with a polymer compound.
1 was prepared.

(Preparation of Pigment Particle Dispersion Liquid 102: Pigment Dispersion Method B) Fastgen Super Magenta RTS (manufactured by Dainippon Ink and Chemicals, Inc.) was used as a pigment, and the method described in JP-A-1 (1999) was used.
According to Production Example 4 described in JP-A-0-120065, a magenta pigment particle dispersion liquid 102 in which the surfaces of the pigment particles are coated with a polymer compound was prepared.

(Preparation of Pigment Particle Dispersion Liquid 103: Pigment Dispersion Method C) C.I. I. Pigment Red 122 (PV Fa
stPink EB-Trans, manufactured by Clariant) 15 g, pyridine 10 ml, and adipic acid dichloride 1
0 ml was dispersed in 500 ml of tetrahydrofuran and reacted at 60 ° C. for 2 hours under a nitrogen stream. After the reaction was completed, the pigment reaction product was filtered off, washed with tetrahydrofuran, and then dispersed in 100 ml of an aqueous t-butyl hydroperoxide solution (70% by mass),
Further, 2 g of sodium hydroxide was added, and the mixture was reacted at room temperature for 24 hours under a nitrogen stream. Then, the reaction product was filtered and washed with tetrahydrofuran, and then the reaction product was dispersed in 150 ml of tetrahydrofuran. 7.5 g of the following monomer mixture 1 was added to this dispersion, and the mixture was reacted at 80 ° C. for 6 hours. After the reaction was completed, an appropriate amount of ion-exchanged water was added to the polymerization reaction product, the pH was adjusted to 7.0 with diethanolamine, and concentration and water addition by ultrafiltration were repeated, and then centrifugation was performed to obtain the target magenta product. A pigment particle dispersion liquid 103 was obtained.

<Monomer mixture 1> Composition ratio: styrene / 2-ethylhexyl acrylate /
n-butyl acrylate / acrylic acid / sodium styrenesulfonate = 64/15/15/15/1 (Preparation of pigment particle dispersion liquid 104: pigment dispersion method D) PV dispersed using dioctyl sodium sulfosuccinate
FastPink EB-Trans (Clariant)
100 g of a 10% by mass aqueous dispersion of the above was taken, and 20 g of the monomer mixture 2 having the following composition, 50 g of ethanol and 0.1 g of potassium persulfate were added thereto, and a polymerization reaction was carried out at 80 ° C. for 6 hours. After the polymerization reaction, concentration by ultrafiltration and water addition were repeated, and then centrifugal separation was performed to prepare a magenta pigment particle dispersion liquid 104.

<Monomer mixture 2> Composition ratio: styrene / 2-ethylhexyl acrylate /
Methacrylic acid = 64/16/15 Table 2 shows the characteristics of each pigment particle obtained as described above.

The secondary volume average particle diameter of the pigment particles shown in Table 2 was measured by the following method.

<Measurement of Average Particle Size of Pigment Particles> Each pigment particle dispersion liquid is 0.1% of SA-5 (Perex OT-P).
After diluting 1000 times with the aqueous solution, measurement was performed using Malvern Zetasizer 1000.

The details of the compound abbreviations shown in Table 2 are as follows. Pigment a: Fastgen Super Magenta RTS
(Manufactured by Dainippon Ink and Chemicals Inc.) Pigment b: PV FastPink EB-Trans
(Manufactured by Clariant) P-6: n-butyl methacrylate / n-butyl acrylate / 2-hydroxyethyl methacrylate / methacrylic acid = 175 / 10.7 / 37.5 / 26.8 P-7: n-butyl methacrylate / n -Butyl acrylate / 2-hydroxyethyl methacrylate / acrylic acid = 171.4 / 6.3 / 37.5 / 34.8 P-8: Styrene / 2-hydroxyethyl methacrylate / n-butyl acrylate / acrylic acid / styrene sulfone Sodium acidate = 64/15/15/15/1 P-9: Styrene / 2-hydroxyethylmethacrylate / methacrylic acid = 64/16/15

[0152]

[Table 2]

<< Preparation of Ink >> Magenta inks 1 to 1 were prepared using the dispersion liquid of the respective colored fine particles and pigment particles prepared above.
26 was prepared. In the preparation of each magenta ink,
In each of the colored fine particles and the dispersion liquid of the pigment particles, pure water, the ink solvent described in Tables 3 and 4, the polyvalent metal ion aqueous solution,
The surfactant and the polymer compound were added to the mixture so as to have the concentrations shown in Tables 3 and 4 and prepared. The amount of each color fine particle and the dispersion liquid of pigment particles added was appropriately adjusted so that the concentration of each color material in the ink was 1: 1. When the concentration of the coloring material in the dispersion liquid is insufficient and the concentration of the coloring material in the ink cannot be adjusted to the target value, the dispersion liquid of the colored fine particles and the pigment particles is decompressed under reduced pressure to remove water, concentrate and It was adjusted.

When iron ions, aluminum ions and calcium ions are used as the polyvalent metal ion aqueous solution, 0.1% aqueous solutions of ferric chloride, aluminum chloride and calcium chloride are added respectively, and Table 3, The polyvalent metal ion concentration shown in Table 4 was adjusted. Further, the pH was adjusted to be a value described in Table 5 below by using a 0.1 mol / L nitric acid aqueous solution and a sodium hydroxide aqueous solution.

Details of the compound abbreviations shown in Tables 3 and 4 are as follows. EG: ethylene glycol gly: glycerin TEGBE: triethylene glycol monobutyl ether DEG: diethylene glycol HDO: 1,2-hexanediol TEG: tetraethylene glycol PG: propylene glycol PYR: 2-pyrrolidinone SA-4: Olphin E1010 (manufactured by Nisshin Chemical Co., Ltd.) , Nonionic surfactant) SA-5: Perex OT-P (manufactured by Kao, anionic surfactant) SA-6: Emulgen 920 (manufactured by Kao, anionic surfactant) SA-7: Rebenol WX (manufactured by Kao, anionic surfactant) Activator) P-10: Takelac W-605 (manufactured by Takeda Pharmaceutical Co., Ltd., urethane-based soap-free latex) P-11: Nipol LX844B (manufactured by Nippon Zeon,
Acrylic latex) P-12: Takelac W-6060 (manufactured by Takeda Pharmaceutical Co., Ltd., urethane-based soap-free latex) P-13: Nipol SX1105 (manufactured by Zeon Corporation,
Styrene-butadiene soap-free latex) P-14: John Kryl 61J (Johnson polymer, water-soluble acrylic polymer) P-15: PVA203 (Kuraray, polyvinyl alcohol)

[0156]

[Table 3]

[0157]

[Table 4]

<< Measurement of Characteristic Value of Each Ink >> With respect to each magenta ink prepared as described above, each characteristic of magenta ink and each colored fine particle in the ink was measured according to the method described below.

<Measurement of Redispersion Coefficient> After collecting 1 ml of each ink and spreading the ink evenly on a washed petri dish,
Leave at room temperature and humidity for 1 week to dry. Next, 1 ml of water was added to the dried product, and the mixture was stirred for 2 minutes with a glass rod to be redispersed. Was measured by the method.

The volume average particle diameter was measured by diluting each of the inks before and after drying 1000 times, and then using a Zetasizer 1000 manufactured by Malvern Instruments Ltd. to obtain a redispersion coefficient according to the above formula (1).

<Measurement of pH and Surface Tension> The pH and surface tension were measured by a conventional method.

Table 5 shows the results obtained as described above. << Formation and Evaluation of Magenta Image >> (Image formation) After storing each magenta ink prepared above in an ink jet cartridge, an image was output using a color ink jet printer PM820C (manufactured by Epson). The output image has an output density of 0% to 1
A wedge image (outputted in a 3 cm × 3 cm patch shape for each density) obtained by dividing 0% between 16 steps was used.
The same data at the same time, Digital Minilab QD-21P
LUS (manufactured by Konica) was used to output on Konica Color QA Paper Type A7 and development processing was carried out to obtain a color silver salt photographic image for comparison.

(Evaluation of Graininess) Regarding the graininess, in order to determine whether graininess equivalent to that of a silver salt photograph was obtained, the wedge image prepared above was prepared at the same time as a color silver salt photograph for comparison. The images were compared and evaluated. The evaluation was carried out by visual evaluation by 20 general evaluators and judged according to the following criteria.

4: 16 people or more evaluated as equivalent to silver salt photograph 3: 12 to 15 people evaluated as equivalent to silver salt photograph 2: 8 to 11 people evaluated as equivalent to silver salt photograph 1: 7 people or less were evaluated as equivalent to the silver salt photograph (evaluation of glossiness) For the glossiness, in order to determine whether or not the glossiness equivalent to the silver salt photograph was obtained, the wedge image created above was The color silver salt photographic image for comparison prepared at the same time was compared and evaluated. The evaluation was carried out by visual evaluation by 20 general evaluators and judged according to the following criteria.

A: 16 or more people evaluated as equivalent to silver salt photographs b: 12 to 15 people evaluated as equivalent to silver salt photographs c: 8 to 11 people evaluated as equivalent to silver salt photographs d: Seven or less people were evaluated as equivalent to a silver salt photograph (evaluation of light resistance) Regarding light resistance, a patch with a reflection density of about 1.0 was used in the xenon fade meter in the image prepared above. After irradiating 70,000 lux of xenon light for 240 hours, the residual ratio of reflection density {(reflection density after irradiation with xenon light) / (reflection density before irradiation with xenon light) × 100 (%)} was calculated. From this residual rate, evaluation was performed according to the following criteria.

[0166] A: Reflection density residual rate is 85% or more B: Reflection density residual rate is 70% or more and less than 85% C: Reflection density residual rate is 50% or more and less than 70% D: Reflection density residual rate is less than 50% Table 5 shows the evaluation results obtained as described above.

[0167]

[Table 5]

As is clear from Table 5, in the comparative example, it was not possible to obtain a sample satisfying all of the graininess, glossiness and light resistance.

On the other hand, each of the samples of the present invention showed excellent light resistance in all the samples, and in terms of graininess and glossiness, had image characteristics equivalent to or better than the color silver salt photographic image used for comparison. I was able to confirm that

Example 2 << Preparation and Evaluation of Color Image >> (Preparation of Colored Fine Particles for Each Color and Pigment Particle Dispersion) Example 1
According to the preparation example 1 of magenta colored fine particles described in 1., a dispersion liquid of yellow, cyan and black colored fine particles was prepared. Here, as the yellow dye, FS Yellow
w 1015 (manufactured by Arimoto Chemical Co., Ltd.) is used as a cyan dye in F
S Blue 1504 (manufactured by Arimoto Kagaku) and Oil Black 860 (manufactured by Orient Chemical) were used as the black dye. As the magenta colored fine particles, the colored fine particles 6 described in Table 1 above were used.

Also, the pigment particle dispersion 1 described in Example 1
A dispersion of pigment particles of each of yellow, cyan and black was prepared according to the preparation method of No. 04. Here, as the yellow pigment, Pigment Yellow 128,
Pigment Blue 15 as a cyan pigment:
3. Carbon black was used as the black pigment. As the magenta pigment particles, the magenta pigment dispersion liquid 104 described in Table 2 above was used.

(Preparation of Ink of Each Color) Using the dispersion liquid of colored fine particles of each color and pigment particles obtained as described above, an ink of each color was prepared according to the constitution of Ink 6 shown in Table 3. Here, the density of the color material is adjusted appropriately so that it is the same as the genuine absorbance for the large format inkjet printer Iguazu 1044SD (manufactured by Konica), and two colors of light and shade are prepared for each color. , Stored in an inkjet cartridge.

Each of the obtained ink jet cartridges of each color was placed on Konica ink jet paper Photolike QP using an ink jet tester equipped with eight piezo type ink jet heads having 512 ejection nozzles, a nozzle diameter of 25 μm and an ejection frequency of 30 kHz. , 1440 × 720 dpi (dpi is 2.54 cm
The image data was output at a pixel density of (representing the number of dots per hit).

By changing the driving voltage of the nozzle,
The droplet velocity was adjusted to be 8 m / sec. At this time, when the amount of the ejected ink droplet was measured, it was 7p.
It was l. Further, the driving conditions were appropriately set so that the low-concentration inkjet image recording liquid was output mainly in the low-to-medium density region, and the high-concentration inkjet image recording liquid was output mainly in the high-density region.

The structure of the head 11 of the piezo type ink jet tester is as shown in FIG. 1 (a). In addition, a cross-sectional view of the head 11 taken along the line AA is shown in FIG.
Shown in.

In FIG. 1A, the head 11 having five ejection nozzles is illustrated for the sake of description, but the second embodiment
In the above, a head having 128 nozzles was used. A piezo element 12 that ejects ink droplets by displacing the piezo element is provided on the head corresponding to each ejection nozzle. A driver IC 13 that supplies a driving signal and a heating signal to the piezo element is arranged on the ink flow path (ink pool).

Further, the thermistor 14 is provided on the discharge nozzle near the piezo element and has a temperature measuring means.

As the output image data, the wedge image used in the first embodiment and the high-definition color digital standard image data "N5 / bicycle" issued by the Japan Standards Association
(Issued in December 1995) was used.

Also, as in the first embodiment, the same image data is copied to Digital Minilab QD-21 PLUS (manufactured by Konica).
Was printed on Konica Color QA Paper Type A7 and developed to obtain a color silver salt photographic image for comparison.

With respect to each of the images obtained as described above, the light resistance, the graininess and the glossiness were evaluated by the method described in Example 1. As a result, the same results as in Example 1 were obtained.
Good results were shown for each color. Also, with regard to graininess and gloss, good results equivalent to or better than the comparative color silver salt photographic image were shown.

[0181]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an inkjet ink having excellent granularity, glossiness and light resistance of an inkjet recorded image, an inkjet cartridge using the same, an inkjet image recording method and an inkjet recorded image. .

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a head of a piezo system inkjet tester used in the present invention.

[Explanation of symbols]

11 heads 12 Piezo element 13 Driver IC 14 Thermistor

Continued front page    F-term (reference) 2C056 EA13 FA04 FC02                 2H086 BA01 BA52 BA55 BA59 BA60                       BA62                 4J039 AD03 AD07 AD09 AD10 AD12                       AD13 AD14 BA31 BA32 BA33                       BA35 BA36 BA37 BA38 BA39                       BE01 BE02 BE03 BE04 BE05                       BE07 BE08 BE12 BE22 BE28                       BE30 EA33 EA35 EA48 GA24

Claims (15)

[Claims] 1. At least one kind of colored fine particles selected from colored fine particles made of a resin containing a dye, colored fine particles made of a resin coated with a dye, and colored fine particles having a surface of a resin containing a dye further coated with a resin. An inkjet ink containing pigment particles, wherein the inkjet ink has a redispersion coefficient represented by the following formula (1) of 0.5 to 5, and the surface of the pigment particles is water-insoluble. An inkjet ink characterized by being coated with a water-dispersible polymer layer. Formula (1) Redispersion coefficient = secondary volume average particle size of colored fine particles and pigment particles after redispersion / secondary volume average particle size of colored fine particles and pigment particles before redispersion 2. The inkjet ink according to claim 1, which has a pH of 7.0 or more. 3. The ink jet ink according to claim 1, which has a surface tension of 25 to 45 mN / m. 4. The secondary volume average particle diameter of the colored fine particles is 10 to 150 nm.
4. The inkjet ink according to any one of 3 to 4. 5. The secondary volume average particle diameter of the pigment particles is
It is 10-150 nm, It is characterized by the above-mentioned.
The inkjet ink according to any one of 1. 6. The inkjet ink according to claim 1, wherein the polyvalent metal ion content is 5 ppm or less. 7. The inkjet ink according to claim 1, wherein the ink solvent content is 5 to 70 mass%. 8. The inkjet ink according to claim 1, further comprising an anionic surfactant. 9. The ink jet ink according to claim 1, further comprising a nonionic surfactant. 10. The inkjet ink according to claim 1, further comprising a cationic surfactant. 11. The inkjet ink according to claim 1, further comprising an anionic surfactant and a nonionic surfactant. 12. The inkjet ink according to claim 1, which contains a water-soluble polymer or a water-insoluble polymer dispersion liquid. 13. An ink jet cartridge comprising an ink containing portion containing at least one ink jet ink according to any one of claims 1 to 12. 14. An ink jet image recording method, which comprises forming an image using at least one ink jet ink according to any one of claims 1 to 12. 15. An inkjet recorded image formed by performing inkjet image recording using at least one inkjet ink according to any one of claims 1 to 12.