JPH10168368A - Ink, applying method thereof and applying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink capable of suppressing the blot of the ink without requiring any pretreatment of a medium for recording or an installation of a special mechanism for a printer, and useful for an ink jet recording method, etc., by including charged particles mainly consisting of a coloring agent and a substance having an opposite charge. SOLUTION: This ink contains (A) a medium for dispersion, (B) charged particles consisting mainly of a coloring agent [e.g. a charge based on the ionic character of a dispersing agent used for dispersing the coloring agent into the component (A)] and (C) a substance having an opposite charge to the component (B) (e.g. having a feather like or a particle like shape). On applying the ink on a medium for recording by loading the ink on an ink jet printer, etc., since a shearing rate is high at the ink discharge part, the component (B) and (C) are separated to reduce the viscosity of the ink for a good discharge. On the impact of ink droplets at the medium for recording, since the shearing rate is reduced, an attracting force works between the components (B) and (C) for restraining the motions between each other to increase the viscosity of the ink before a blot spreads so as to be able to suppress the blot of the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the application of an ink for obtaining a high-quality image or a uniform solid color without performing a bleeding preventing process on a recording medium. In particular, it is suitable for applying ink to a recording medium by ink jet, spray, padding, or the like.

[0002]

2. Description of the Related Art Ink jet recording systems are roughly classified into an on-demand type and a continuous type. In each case, low-viscosity ink of several centipoise is generally used for stable ejection of ink droplets.

However, when such a low-viscosity ink is used, bleeding of the ink on a recording medium occurs, and a high-quality image cannot be obtained. To solve this problem, for example, as disclosed in Japanese Patent Application Laid-Open No. 61-215787, the recording medium is pre-processed using a specific material corresponding to a specific ink, and the ink and the pre-processed material are used. A method of suppressing bleeding by reacting
As disclosed in Japanese Unexamined Patent Application Publication No. 77-244 and Japanese Patent Application Laid-Open No. 58-24492, the degree of freedom of ink is a relatively high method, and a recording medium is pretreated using a water-soluble resin or a highly water-absorbing resin. In short, almost all of the proposed methods, such as a method of holding ink in these resins to suppress bleeding, have been solved by performing a pretreatment on a recording medium.

[0004] However, according to the method of pre-processing these recording media, for example, in an ink jet printer used by connecting to a personal computer in an office or an individual, the running cost is high because special paper must be used. A problem arises in that the paper at hand cannot be used. Further, as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 61-215787 and the like, the same can be said for application to ink jet dyeing using a recording medium as a fabric.

To solve such a problem, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 8975 discloses a method in which ink is heated on a recording medium to increase the viscosity, thereby suppressing bleeding. According to this method, since the pretreatment of the recording medium is not required, the above-described problem can be avoided. However, in this case, a heating mechanism must be provided in the ink jet printer, and compared with a normal printer. Problems such as an increase in size and an increase in the cost of electric power arise.

[0006] The above-mentioned problems occur not only in ink jet recording but also in spray recording in which only the ink discharge mechanism is largely different.

[0007]

SUMMARY OF THE INVENTION The present invention solves the problems of the various bleeding control methods described above, does not require any pretreatment on the recording medium, and does not provide the printer with a special mechanism. It is intended to suppress ink bleeding.

[0008]

Means for Solving the Problems The ink of the present invention has the following constitution to solve the above problems.

That is, an ink comprising at least a charged particle (A) mainly composed of a colorant, a substance (B) having the opposite charge, and a medium.

[0010] The ink application method of the present invention has the following configuration.

That is, an ink characterized by containing at least a charged particle (A) mainly composed of a colorant, a substance (B) having the opposite charge, and a medium is used as a recording medium. A method of applying an ink to the ink by an inkjet method, a spray method, or a padding method.

Further, the ink applying apparatus of the present invention has the following configuration.

That is, an ink loaded with an ink characterized by containing at least a charged particle (A) mainly composed of a colorant, a substance (B) having the opposite charge, and a medium. An ink application device comprising a tank and a mechanism for discharging the ink.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail.

The ink of the present invention contains at least a charged particle (A) mainly composed of a colorant, a substance (B) having the opposite charge, and a medium. By adopting this configuration, when the ink is allowed to stand still, the charged particles mainly composed of the colorant (A)
And the material (B) having the opposite charge, an attractive force acts to restrict the movement of each other, so that the viscosity of the ink as a whole increases. However, when the ink flows,
(A) and (B) are separated from each other, and the viscosity of the ink as a whole decreases. This is easily confirmed by the viscosity of the rotary viscometer. That is, when the rotation is low (that is, when the shear speed is low), the apparent viscosity of the ink is high, while when the rotation is high (that is, when the shear speed is high), the apparent viscosity of the ink is low (the apparent viscosity is low). Is obtained by dividing the shear stress generated at a certain shear rate by the shear rate.) Such a phenomenon is known as thixotropy (pseudoplasticity). When such an ink is loaded on an ink jet printer or the like and applied to a recording medium, a portion where the ink is discharged corresponds to an environment with a high shear rate. Therefore, the ink viscosity is substantially reduced and the ink is ejected, and when the ink droplet lands on the recording medium, it corresponds to an environment of a low shear rate, and the viscosity increases before the bleeding spreads, and the bleeding is suppressed. is there.

For the purpose of the present invention, when the apparent viscosity at a shear rate of 380 / sec is η ₁ and the apparent viscosity at a shear rate of 38 / sec is η ₂ , the thixotropic property satisfying the relationship 2η ₁ <η ₂ is satisfied. Is more preferably used. Further, under such conditions, when used in the ink jet method, η ₁ is 20
cp or less, more preferably 10 cp or less, still more preferably 5 cp or less, and 3 c
It is particularly preferable that it is p or less. When used in the spray method, η ₁ is preferably 100 cp or less, and 50 c
It is more preferably at most p, particularly preferably at most 20 cp. When used in the padding method, η ₁ is preferably at most 50 cp, more preferably at most 30 cp, particularly preferably at most 20 cp. In the actual measurement, there are restrictions on the apparatus and problems of accuracy. Therefore, the shearing speed of 380 / sec in the present invention is actually 360 to 400 / sec, and the shearing speed of 38 / sec is 30 to 50 / sec.
/ S range.

Japanese Patent Application Laid-Open No. 62-101669 discloses a method for adding a specific water-soluble polymer as such a thixotropic ink. However, inks to which such a water-soluble polymer is added generally have the problem of deteriorating ink ejection characteristics such as clogging of nozzles in ink jet printers, dropping of ink droplets, and generation of satellite droplets. On the other hand, the present invention does not require the addition of a water-soluble polymer, and thus has an advantage of excellent ink ejection characteristics.

The source of the charge of the charged particles (A) mainly composed of the colorant and the charged substance (B) is not particularly limited, but it is easy to use the ionic group when the medium is used. Preferred. In particular, the charge of the charged particles (A) mainly composed of a colorant is mainly based on the ionic group of a dispersant that disperses the colorant in a medium. It is preferable because it can be performed. That is, various known anionic surfactants and cationic surfactants are preferably used as the dispersant.

The substance (B) having the opposite charge is not particularly limited. For example, when the above-mentioned ionic group is used, a divalent or higher valent metal salt, a polyanion or a polycation is preferably used. A more preferred form is particulate, which is charged. Furthermore, feathers are preferable among the particles.

The basic idea of the present invention is as described above.
In practice, the attraction between particles may be so strong that the particles aggregate and do not redisperse even if a shear rate is given. Therefore, it is important to give a moderate repulsion force to make the overall attractive force,
This leads to high stability of the ink. The source of the repulsive force is not particularly limited, but the charged particles mainly composed of the colorant (A) and / or the substance having the opposite charge (B)
In addition, it is achieved by adsorbing or immobilizing a dispersant that is dispersed in a medium without being charged. Specifically, for example, a nonionic surfactant is used.

The particle diameter of the charged particles (A) mainly composed of the colorant and the substance (B) having the opposite charge (in the case of (B), particles) is not particularly limited. Is preferably 0.01 to 10 μm, more preferably 0.02 to 5 μm, even more preferably 0.03 to 1 μm, and 0.04 μm.
It is particularly preferable that the thickness be 0.7 μm.

The ratio between the charged particles (A) mainly composed of a colorant and the substance (B) having the opposite charge is as follows:
Since the above-mentioned particle size is also involved, it should be appropriately selected within a range that achieves the object of the present invention, but is preferably from 10: 1 to 1:10 by weight. More preferably, 5: 1
The ratio is 1: 5, preferably 3: 1 to 1: 3, and more preferably 1.5: 1 to 1: 1.5.

The colorant of the ink of the present invention is not particularly limited, and a dye or a pigment may be used. Preferably, the colorant is substantially insoluble or very hardly soluble in a medium. For example, when the medium is mainly composed of water, various disperse dyes and pigments are preferable examples.

The substance (B) having a charge opposite to that of the charged particles (A) mainly composed of a colorant is not particularly limited, and may be particles mainly composed of a colorant. It may be a substance that is not involved in the process. In the former case, the color or type of the colorant may be the same as or different from the colorant of the particles (A) mainly composed of the colorant. It may be designed according to the purpose. For example, when a dark color is desired to be expressed, the same color may be used. In the latter case, a common composition can be used when preparing multicolor inks, so that the preparation is simplified and the production cost can be suppressed. In this case, as a substance having a negative charge, for example, an inorganic substance such as colloidal silica (silicon dioxide) mainly composed of silicon oxide is a preferable example because it has a charge itself. In addition, for example, latex particles or the like in which acrylic acid or methacrylic acid monomer is emulsion-copolymerized with, for example, styrene or methacrylic acid ester, divinylbenzene, etc., various anionic surfactants and polyanion compounds (for example, polyacrylic acid) Acid or aromatic sulfonic acid-formalin condensate). Examples of the particles include fine particles mainly composed of a polyester resin or an epoxy resin, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2,2′-dihydroxy-4,4′-dimethoxybenzophenone. , Ethyl-2-cyano-3,3'-diphenylacrylate, 2,6-di-t-butylphenol, 4,4'-bis- (2,6-di-t-butylphenol), 1,3,5- Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl)
Benzene, 4-isooctylphenol, 4,4'-dioxydiphenyl, 2,5-di-t-butylhydroquinone, barite, precipitated barium sulfate, chalk, precipitated calcium carbonate, chalk, clay, talc, silica white,
Examples include alumina white, titanium white, bentonite, calcium silicate, aluminum silicate, titanium oxide, zinc white, lithopone, lead white, zircon oxide, and antimony white. Conversely, as particles having a positive charge, for example, inorganic substances such as colloidal silica mainly composed of silicon oxide, alumina sol (alumina oxide) and the like, which have been subjected to cationic surface treatment, are preferable. In addition, various particles dispersed and stabilized by various cationic surfactants and polycation compounds can be used. The particles used for this purpose are the same as those described above, and will not be described.

As the ink medium of the present invention, as described above, a medium mainly composed of water is preferable since the object can be easily achieved, but a so-called solvent system may be used.

Examples of preferred combinations of the media of the ink of the present invention are media composed of water and an organic solvent. Examples of the organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and polyethylene glycol. Propanediol,
Dipropylene glycol, tripropylene glycol,
Glycols such as butanediol, pentanediol, hexylene glycol, and thiodiglycol; and polyhydric alcohols such as glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether. At least one of lower alkyl ethers, amines such as triethanolamine, and pyrrolidones such as 2-pyrrolidone and N-methyl-2-pyrrolidone can be used. Particularly preferred is a liquid composed of water and an alkylene glycol having 3 to 6 carbon atoms.

The ink of the present invention may further contain various other additives as ink components. For example, a binder, a surfactant, a pH adjuster, a preservative, an antifoaming agent, a conductivity adjuster, a viscosity adjuster, a chelating agent and the like can be blended.

The method of applying the ink of the present invention is a method of applying the ink described above to a recording medium by an ink jet method or a spray method. By adopting such a configuration, a high-quality image in which bleeding is suppressed can be obtained without performing bleeding prevention processing on a recording medium, which is almost indispensable in the past.

The recording medium used in the present invention includes:
Various materials targeted by the ink jet recording method and the spray recording method are targeted. For example, paper, metal, plastic, film, yarn, fabric, fabric product, food, glass,
Pottery etc. are mentioned. Preferably, the material is a material in which bleeding is conspicuous, and is a structure made of fine fibrous materials, that is, a paper, a thread, a fabric, a fabric product, or the like. Particularly preferred is a fabric. In addition, fabrics are generally roughly classified into woven fabrics, knitted fabrics, nonwoven fabrics and the like, and the present invention can cover all of them. However, the effects of the present invention (the difference between the amount of bleeding between the conventional low-viscosity ink and the ink of the present invention) Is most evident in textiles.

When the colorant is a dye appropriately selected according to the recording medium, it is also preferable to carry out ink-jet printing on the recording medium using the ink of the colorant and then dye the dye on the recording medium. Things. Since the selection of dyes according to the recording medium is widely known in the dyeing industry, only a very basic example will be given here.For example, a disperse dye, silk, Acid dyes and reactive dyes for polyamide-based recording media such as nylon, direct dyes and reactive dyes for cellulose-based recording media such as cotton, and basic dyes for acrylic-based recording media. It is. In the case where the dye is dissolved in the medium, for example, when a water-soluble dye is selected when the medium is aqueous, the water-soluble dye may be substantially insolubilized with a suitable method before use. For example, addition of a salt such as sodium sulfate or ammonium sulfate to lower the solubility, absorption by porous fine particles for use, or microencapsulation may be mentioned, but not limited thereto.

Unexpectedly, the present invention is not only effective for printing methods such as ink jet method and spraying method, but also for patterns such as characters, pictures, patterns, and identification marks. It has been found that expressing a solid color by padding using the ink of the present invention also has an effect of being able to express a solid color without unevenness. This is particularly effective when the above-described cloth is used as a recording medium.

When the coloring agent is a pigment, it is preferably used, for example, for printing on paper used in offices and individuals. Further, it can also be used for printing on blended products of polyester / cotton or polyester / wool in fabrics and the like. In such a case, it is more preferable that the ink contains a binder for fixing the colorant to the recording medium. In general, particularly for offices and individuals, in order to obtain a full-color image, at least three colors of yellow, cyan, and magenta, or four colors of black in addition to them are often used, and the present invention may conform to it. Not only that, a fluorescent pigment, a pigment for imparting metallic luster, a pigment whose color changes depending on a temperature change, and the like can also be used. That is, in the present invention, a pigment suitable for the purpose may be selected and used irrespective of the kind thereof, such as an organic pigment, an inorganic pigment, and a composite pigment.

Alternatively, the colorant is preferably used as a dye for printing on a sheet of paper or film, and then superimposing the printed surface on a fabric or the like and heating to dye the fabric. Available.

The ink applying apparatus of the present invention includes an ink tank loaded with the ink having the above-described structure and a mechanism for discharging the ink. The ink discharging mechanism may be an ink jet system or a spray system. Can be
The inkjet system is not particularly limited, and the on-demand system uses a piezoelectric element or a heating element, and the continuous system uses a charging voltage control type, a deflection voltage control type, a Hertz type, or the like. However, the more preferable one will be described later. In a more preferred form, the ink tank of the ink applying device to which the ink is loaded is provided with at least a means for stirring the ink in order to ensure fluidity and, in some cases, suppress sedimentation. As this stirring means, a generally used stirring blade or the like or a water jet pump or the like is sufficient, and a special stirring mechanism is not required. However, depending on the combination of the inks of the present invention, the whole system may be in a very slight gel state to suppress sedimentation. In such a case, there is no need for a means for stirring.

It is also preferable to provide a mechanism for capping the vicinity of the nozzle for discharging ink. Alternatively, a mechanism for wiping the vicinity of the nozzle is preferably provided.

Preferably, a mechanism is provided to deform the ink flow path near the nozzle. As a result, the ink viscosity is reduced, and smooth ink ejection can be ensured. The deformation is preferably caused by high-frequency vibration. As a deforming means, one using an electromagnet or one using a piezoelectric (piezo) element is used, but a piezoelectric element is preferable in terms of response speed. In particular, it is particularly preferable that the means for generating ink droplets is a piezoelectric element. For example, an on-demand type ink drop generating mechanism using a Stemme type or Gould type as a prototype or a continuous type ink drop generating mechanism using a piezoelectric element is preferable.

Further, an ink applying apparatus having a mechanism for forcibly sending out the supply of ink from the ink tank to the ink discharge section using a pump or the like is particularly preferable.

[0038]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. It should be noted that the validity and scope of the rights of the present invention are not limited or limited thereby.

The apparent viscosity of the ink was measured with a rotary viscometer (RE100L viscometer, Toki Sangyo Co., Ltd., rotor (cone): 1 ゜ 34 ′ × R24). The value of the apparent viscosity is ±
Includes about 20% error.

Example 1 First, a dispersion of charged particles (A) mainly composed of a colorant was prepared as follows. To obtain a full-color image, four types were used as colorants.

First, CI Disperse Yellow 82, CI Disperse Red 362, CI Disperse Blue 87 and blended black were used as coloring agents, each of which was a sulfonated product of ethylene oxide adduct of styrene-added phenol, which is an anionic surfactant. And dispersed in water.

Although the number of moles added and the degree of sulfonation of each group of the anionic surfactant are arbitrary and do not significantly affect the effects of the present invention, styrene addition in the following examples was carried out. The number of moles was 5, and the number of moles of ethylene oxide added was 10. Next, a nonionic surfactant (Pluronic L-44, Asahi Denka Co., Ltd.) composed of an ethylene oxide chain and a propylene oxide chain was added to each of the above four types of dispersion liquids, and the charge mainly composed of the colorant was added. A dispersion of particles (A) was obtained.

Next, a dispersion of particles (B) having a charge opposite to the particles (A) having a charge mainly composed of a colorant was prepared as follows. This is commonly used for each of the above colors. Nissan Chemical Industries, Ltd. Snowtex AK (cationically treated colloidal silica) and polyethylene glycol fatty acid ester-based nonionic surfactant (Nonion L-4, Nippon Oil & Fats Co., Ltd.)
Was added to obtain a dispersion of the particles (B).

A dispersion of particles (B) having opposite charges was mixed with each of the dispersions (4 types) of particles (A) having charges mainly composed of the above-mentioned coloring agent to obtain inks of the present invention. The apparent viscosities of the obtained inks were measured with a rotary viscometer. As a result, all the inks were about 3 cp at 100 rpm (shear speed of about 380 / sec) and about 20 cp at 20 rpm (shear speed of about 80 / sec). At 5 cp and 10 rpm (shear rate of about 38 / sec), the thixotropy was about 8 cp.

These inks were loaded into a color inkjet printer IO-735, manufactured by Sharp Corporation, and an image was drawn on PPC paper for a copying machine widely used in offices. As a result, all the inks were ejected normally. In addition, an image without feathering or the like could be obtained.

Example 2 An ink obtained by further adding ethylene glycol and a preservative as a drying inhibitor to the ink prepared in Example 1 was provided with a cap mechanism in a nozzle, and an ink tank was agitated. It was loaded into a four-color charge deflection type continuous ink jet printer provided with a mechanism. Using this, inkjet printing was carried out on a plain woven fabric composed of polyester fibers that had undergone a refining process, in which the warp yarn was non-twisted and the weft yarn was strongly twisted. As a result, high-quality image without bleeding was obtained.

Next, the printed fabric was colored by high-temperature steaming, and then soaped. As a result, a very high-quality image could be dyed without bleeding.

Thereafter, the nozzle was capped and the ink tank was kept stirring for one month. After the same experiment was repeated, the ink was ejected normally and the obtained image was of high quality without bleeding. Met.

Example 3 First, a dispersion of charged particles (A) mainly composed of a colorant was prepared as follows. To obtain a full-color image, four types were used as colorants. First, as a coloring agent, Sanyo Dyeing Co., Ltd. Emac
ol CT Yellow 4627, Red 4315, Blue 4814, and Black 4926 were each dispersed in water. These were cationic dispersions.

Next, a polyethylene glycol alkyl ether-based nonionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd. Neugen ET100) was added to each of the above four dispersions.
Having a charge mainly composed of a coloring agent (A)
Was obtained.

Next, a dispersion of particles (B) having a charge opposite to the particles (A) having a charge mainly composed of a colorant was prepared as follows. This is commonly used for each of the above colors. Nissan Chemical Industries Snowtex 20L (anionic colloidal silica)
Was added with a nonionic surfactant of sorbitan ester ether type (Nonion LT-221, manufactured by NOF Corporation) to obtain a dispersion of particles (B).

A dispersion of particles (B) having the opposite charge was mixed with each of the dispersions (4 types) of the particles (A) having charge mainly composed of the above-mentioned coloring agent to obtain an ink of the present invention.

The obtained inks were measured with a rotary viscometer (R type viscometer, manufactured by Toki Sangyo Co., Ltd.). As a result, all the inks showed the same thixotropic property as in Example 1.

These inks were used in a Seiko Epson Corporation
The image was loaded on a color inkjet printer MJ-800C, and an image was drawn on PPC paper for a copying machine widely used in offices. As a result, an image was ejected normally, and an image free from feathering and the like was obtained. I got it.

Example 4 An ink obtained by further adding diethylene glycol as a drying inhibitor and a preservative to the ink prepared in Example 3 was loaded into the continuous ink jet printer used in Example 2. did. Using this, inkjet printing was performed on a blended fabric composed of polyester short fibers and cotton that had undergone a refining process. As a result, high-quality image without bleeding was obtained.

Example 5 The ink prepared in Example 4 was further used as a binder component by Sanyo Dyeing Co., Ltd. Ema
col CT binder D2301, DCT 2803,
D2600 was added.

This ink was loaded in the continuous ink jet printer used in Example 2, and ink jet printing was performed on the cloth used in Example 4.

Next, the printed fabric was dried and then heat-treated at 150 ° C. for 2 minutes. As a result, a very high-quality image could be fixed without bleeding.

Example 6 As a dispersion of charged particles (A) mainly composed of a colorant, a dispersion of a blended black disperse dye stabilized and dispersed by an anionic surfactant was used.

As a dispersion of charged particles (B) having a charge opposite to that of charged particles (A) mainly containing a colorant, a dispersion of alumina sol-100 having a feather shape is used. Using.

A polyester cloth was padded with a liquid obtained by mixing the two, and squeezed with a mangle.
It was dried in a tenter.

Next, the color was developed by high-temperature steaming and washed by a conventional method. The obtained dyed fabric was very excellent in levelness.

Comparative Example 1 A similar operation was performed using only the dispersion of the charged particles (A) mainly composed of the colorant in Example 1.

As a result, the obtained dyed fabric had migration and uneven dyeing.

[0065]

According to the present invention, a high-quality image free from bleeding can be obtained without preventing bleeding on the recording medium.

Claims (28)

[Claims] 1. An ink comprising at least a charged particle (A) mainly composed of a colorant, a substance (B) having an opposite charge, and a medium. 2. The ink according to claim 1, which is used in an ink jet method, a spray method, or a padding method. 3. The ink according to claim 1, wherein the substance (B) is in the form of particles. 4. The weight ratio between the charged particles (A) mainly composed of a colorant and the substance (B) having the opposite charge is 10: 1 to 1:10. 1
Or the ink according to 2. 5. The method according to claim 1, wherein the charge of the charged particles mainly composed of a colorant (A) and / or the substance (B) having the opposite charge is expressed by an ionic group. 3. The ink according to 2. 6. The method according to claim 1, wherein the charged particles (A) mainly composed of a colorant are charged mainly by an ionic group of a dispersant for dispersing the colorant in a medium. 3. The ink according to 2. 7. A charged particle mainly composed of a colorant (A) and / or a substance (B) having an opposite charge.
3. The ink according to claim 1, wherein the ink contains a dispersant that disperses in a medium without being charged. 4. 8. The ink according to claim 7, wherein the dispersant dispersing in the medium without being charged is a nonionic surfactant. 9. The ink according to claim 1, wherein the colorant is a dye. 10. The ink according to claim 1, wherein the colorant is a disperse dye. 11. The ink according to claim 1, wherein the colorant is a pigment. 12. The ink according to claim 1, wherein the medium contains water. 13. The ink according to claim 1, wherein the substance (B) having the opposite charge to the charged particles (A) mainly composed of the colorant is mainly composed of the colorant. 14. The ink according to claim 1, wherein the substance (B) having the opposite charge to the charged particles (A) mainly composed of the colorant is mainly composed of an inorganic substance. 15. The ink according to claim 1, wherein the ink has thixotropic properties. 16. ₁ The apparent viscosity at a shear rate of 380 / sec eta, when the ₂ an apparent viscosity eta at a shear rate of 38 / sec, 2η ₁ <claim 1 or characterized by satisfying the eta ₂ of the relationship 3. The ink according to 2. 17. An apparent viscosity η _{1 at a} shear rate of 380 / sec is not more than 20 cp.
The ink according to the above. 18. A method for applying an ink, comprising applying at least the ink according to claim 1 to a recording medium by an ink jet method, a spray method, or a padding method. 19. The method according to claim 18, wherein the recording medium is a cloth. 20. A method according to claim 1, further comprising the steps of: applying an ink in which the colorant is a dye to the recording medium; and dyeing the recording medium to which the ink has been applied with the dye in the ink. 19. The method for applying an ink according to item 18. 21. The method according to claim 18, wherein the colorant is a pigment. 22. An ink application device comprising at least an ink tank loaded with the ink according to claim 1 and a mechanism for discharging the ink. 23. The ink application device according to claim 22, wherein the ink tank of the device is provided with at least means for stirring the ink. 24. The ink application device according to claim 22, further comprising means for capping a vicinity of a nozzle for discharging the ink. 25. The ink application device according to claim 22, further comprising means for deforming the ink flow path in the vicinity of the nozzle. 26. The ink application device according to claim 25, wherein the means for deforming the ink flow path is a piezoelectric element. 27. The apparatus according to claim 25, wherein the means for deforming the ink flow path is an ink droplet generating means. 28. The ink supply device according to claim 25, further comprising a pump for supplying ink to a mechanism for discharging ink from the ink tank.