JPH10140057A - Recording liquid and recording image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a recording liquid for ink jet printers, not blotting and permeating into recording paper, giving high image concentrations, excellent in fixity and water resistance, not clogging ink jet heads, and excellent in extrusion stability, and to provide a method for forming an image with the recording ink. SOLUTION: This recording liquid comprises water, a coloring agent, resin particles having a film-forming property at the ordinary temperature, and water- insoluble solid particles not having a film-forming property at the ordinary, wherein the solid particles comprise inorganic particles and/or synthetic polymer particles. The recording liquid is used in an image-recording method for extruding the drops of the recording liquid from a head to record on a recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a recording liquid and an image recording method. More specifically, the present invention relates to a recording liquid containing water, a colorant and resin fine particles, and an image recording method using the same.

[0002]

2. Description of the Related Art With respect to an output device of an information device such as a computer, an image recording method in which droplets of a recording liquid are ejected from a head to perform recording on a recording medium has recently been adopted as a system which is low in running cost and easy to colorize. Is attracting attention. In this method, a dye aqueous solution containing water and a dye as a main component is conventionally used as a recording liquid for an ink jet printer, but when the recording liquid ejected from a nozzle adheres to the recording paper, the recording liquid is discharged. There was a problem that the ink bleeds on the recording paper, resulting in dots that are significantly larger than the recording droplets formed during flight, and that the density of the recorded image is low, and thus the image quality is low. Further, since the recorded image has low water resistance, there is a problem that the image easily bleeds or flows due to water. There is also a problem that the light resistance is low, and the image is easily discolored by irradiation with light such as sunlight.

Conventionally, in order to solve these problems of an aqueous dye solution, a technique of adding film-forming resin fine particles to a recording liquid has been disclosed. That is, the addition of latex as resin fine particles is disclosed in JP-B-60-32663, and the addition of a water-dispersible resin having a carboxyl group and a nonionic hydrophilic group is described in JP-A-5-239392. The addition of molecules is disclosed in JP-A-5-255628, the addition of polyester particles having an ionic group is disclosed in JP-A-6-340835, and the addition of dyed resin fine particles is disclosed in JP-A-5-255567. ing. Japanese Patent Publication No. 7-47355 discloses a technique in which resin fine particles such as polyester and a crosslinking agent are separately compounded to crosslink the resin on a recording medium.

[0004]

However, the above-mentioned Japanese Patent Publication No. Sho 60-32663 and Japanese Patent Laid-Open Publication No. Hei 5-23939.
No. 2, JP-A-5-255628, JP-A-5-256628
In the recording liquids disclosed in JP-A-340835, JP-A-5-255567 and JP-B-7-47355, all of the recording liquids are discharged at the discharge port portion of the recording head.
As the water in the recording liquid evaporates due to contact with air, the film-forming action of the resin fine particles starts, causing clogging at the discharge port, making it impossible to discharge the recording liquid stably Met. Further, even if the ink can be discharged in the initial stage, it is impossible to completely prevent the recording liquid from bleeding due to the capillary phenomenon on the recording paper fibers, and it is impossible to obtain a high-quality image. Furthermore, it was not possible to completely prevent the recording liquid from penetrating into the inside of the recording paper, and there was a limit to high image density and high image quality. Similarly, there was a limit to water resistance. Further, in the above-described conventional recording liquid, it is conceivable to dilute the recording liquid by adding water in order to avoid clogging at the discharge port. However, the content of fine resin particles contained in the droplets, that is, the content of resin solids contributing to image formation was reduced, and therefore the image density was significantly reduced, making it impossible to obtain a high-quality image. That is, in the recording liquid of the conventional disclosure,
It has been impossible to achieve both high image density and high image quality by increasing the content of resin fine particles (higher resin solid content) and avoiding clogging at the discharge port.

In order to solve these problems, Japanese Patent Laid-Open Publication No. Hei. 3-160068 discloses a minimum film forming temperature (MFT) of a recording liquid.
A method of preventing clogging at a nozzle by using a material having a temperature of 40 ° C. or higher is disclosed in Japanese Patent Application Laid-Open No. HEI 3-160069. A method for preventing clogging by eliminating the affinity with the inside of the nozzle by using the above polymer is disclosed. However, in these methods, since the time for forming the resin film on the recording paper at normal temperature is long, it is impossible to completely prevent the resin paper from penetrating into the recording paper, and it is not possible to obtain a sufficiently high image density. In addition, there is also a defect in fixing strength that the strength of the film is weak and the film easily peels off due to friction or overwriting by a ballpoint pen. JP-A-4-370166
Japanese Patent Application Laid-Open No. H05-1254 discloses a method in which after recording with these recording liquids, a resin film is heated so as to have sufficient fixing strength to form a film. There is a drawback that new additional means such as a device is required and power consumption is increased.

As another solution, Japanese Patent Laid-Open No.
No. 113740 discloses a method in which an inorganic salt such as chloride or hydroxide is added to a recording liquid to absorb moisture in the air to prevent the nozzle from drying and solidifying. However, it has disadvantages such as the corrosion of the film, the stability of the film with respect to humidity, the transparency of the film is reduced, and the coloring property of the secondary color is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to eliminate bleeding or penetration of a recording liquid on recording paper, to increase image density, to improve fixability and water resistance. An object of the present invention is to provide a recording liquid for an ink jet printer, which is excellent and has excellent ejection stability without clogging, and an image forming method using the same.

[0008]

The recording liquid of the present invention, which can achieve the above objects, comprises water, a colorant, resin fine particles having film-forming properties at room temperature, and water-insoluble and non-film-forming materials at room temperature. Wherein the solid fine particles are inorganic fine particles and / or synthetic polymer fine particles. Further, an image recording method of the present invention is to perform recording on a recording medium by discharging recording liquid droplets from a head, and is characterized by using the above recording liquid.

In the recording liquid of the present invention, the solid fine particles are non-colored solid fine particles, and are preferably substantially spherical, and the solid fine particles have an average particle size of 0.05 to 5 μm.
It is preferred that The colorant is a pigment or a dye, and preferably has a pigment content of 1 to 50% by weight or a dye content of 0.2 to 40% by weight. Further, the resin fine particles are preferably self-crosslinkable resin fine particles.

According to the present invention, a recording liquid in which a colorant and resin fine particles having film forming properties at room temperature are dispersed in water is made to contain solid fine particles which are water-insoluble and non-film forming at room temperature. In addition, it is possible to achieve high image density and no clogging at the discharge port of the recording head without sacrificing the fixing property.
Therefore, it is possible to obtain a recording liquid for an ink jet printer which has high image quality and excellent ejection stability without clogging.

The range of "normal temperature" in the present invention is as follows.
Generally, it refers to the temperature range in which humans live in daily life, and more specifically means the range of -10C to 40C. The term “film-forming at room temperature” refers to -10 ° C to 40 ° C.
The minimum film formation temperature (MFT) must be 40 ° C. or lower for this purpose.

In the present invention, “water-insoluble” refers to
It means that it is stably present in a solid state without being dissolved in pure water. Specifically, it means that its solubility in pure water is 0.1 wt% or less at room temperature. In the present invention, “non-film-forming property” refers to a range of room temperature, specifically −
It means that solid particles do not fuse with each other due to fusion or melting in the range of 10 ° C to 40 ° C. In this case, it is necessary that the material of the solid fine particles has a minimum film formation temperature (MFT) of 40 ° C. or higher. Further, regarding the solid fine particles in the present invention, “non-colored solid fine particles” means solid fine particles which are not colored by a so-called pigment or dye, and the non-colored solid fine particles themselves are not pigments. More specifically, it indicates that the material of the solid fine particles is transparent or white. When dispersed in a powder or liquid phase, the appearance may be white due to the scattering of light and the refractive index.

In the present invention, “substantially spherical” means that the shape of the particles is close to a true sphere. The most common method for measuring the degree of sphericalness of fine particles is to use an optical microscope or a method in which particles are dispersed (in a liquid or gaseous phase, individual particles are separated). This is a method of measuring a two-dimensional particle profile by observing with an electron microscope or the like. Specifically, the enlarged image is subjected to two-dimensional image processing to measure the area S and the perimeter L of each particle,
Shape factor defined by the ratio (= L / 2 (πS)
By calculating ( ^1/2 × 100), it is possible to know the degree of the particles close to a true sphere. This shape factor (L / 2
(ΠS) ^1/2 × 100) is 100 for a perfect circle, about 105 for a regular hexagon, and about 113 for a square, and becomes larger as the shape becomes farther from the perfect circle. Since the dispersed particles can be considered to be projected two-dimensionally without bias, the average value of these values (the average value of about 100 or more particles) is 100.
It can be determined that the particle shape is closer to a true sphere as it approaches. In the present invention, the fact that the solid fine particles are substantially spherical means that the solid fine particles have a value of 200 or less in terms of the shape factor.

In the present invention, the following effects are considered to be the reason why the above-described excellent recording liquid characteristics can be obtained. The first effect is that the approach between the resin fine particles in the recording liquid is prevented by the presence of non-film-forming solid fine particles. This has the effect of reducing the approach and collision probability between the resin fine particles. The second effect is
Since no fusion occurs between the resin fine particles and the solid fine particles, the fluidity of the recording liquid can be stably ensured by the presence of the solid fine particles. By the total action of the above actions, from the approach of the resin fine particles in the recording liquid, the collision,
It is considered that a series of processes as a cause of clogging at a print head discharge port leading to fusion and film formation (film formation) are hindered.

Further, when the recording liquid adheres to the recording medium, the viscosity of the recording liquid rapidly increases due to water permeation into the recording medium, and resin particles are fused to form a solid content of the recording liquid. Is formed and fixed while remaining near the surface of the recording medium. At this time, the colorant and the solid fine particles are adsorbed by the resin fine particles, or are taken into the film by the film forming action and remain on the surface of the recording medium. For this reason, there is no bleeding or permeation of the recording liquid, a film containing a high-concentration colorant is formed on the surface of the recording medium, and an image having a high optical density can be recorded. In addition, since the resin fine particles and the solid fine particles are all contained as solids, a strong solid film containing a colorant can be formed on the surface of the recording medium. For this reason, high image density of the film of the recording liquid and good fixability can be achieved simultaneously with achieving the above-described prevention of clogging.

Furthermore, by using self-crosslinkable resin fine particles as the resin fine particles, an image can be formed more quickly on a recording medium by the high-speed film forming property of the self-crosslinkable resin fine particles. In other words, immediately after the droplets of the recording liquid flying from the recording head adhere to the recording medium, the crosslinking reaction of the self-crosslinkable resin fine particles progresses rapidly with the evaporation of water in the recording liquid and the permeation of the paper. A strong image film in which the colorant is confined in the resin is rapidly formed. Furthermore, the film formation of other co-existing self-crosslinkable resin fine particles and non-crosslinkable resin fine particles also proceeds, thereby preventing bleeding and penetration of the recording liquid, and dispersing and coloring the resin and the resin. It is possible to form an image having high image density and high water resistance composed of an agent on a recording medium such as paper.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. The resin particles capable of forming a film at room temperature used in the present invention (hereinafter, the resin particles capable of forming a film at room temperature dispersed in water are simply referred to as “resin particles”) are, for example, acrylic silicone resin particles, fluorine, etc. Resin particles, acrylic resin particles, polyester resin particles, vinyl acetate resin particles, vinyl chloride resin particles, styrene-butadiene polymer resin particles, polyurethane resin resin particles, polystyrene resin particles, vinyl acetate-acryl Resin fine particles such as copolymer-based resin fine particles, vinyl acetate-acrylamide copolymer-based resin fine particles, ethylene-vinyl acetate copolymer resin, epoxy resin-based resin fine particles, polyamide resin-based resin fine particles, and silicone-based resin fine particles. it can.

As examples of the self-crosslinkable resin fine particles used in the present invention, among the above, acrylic silicone resin fine particles, acrylamide resin fine particles and the like can be used. Particularly, among the acrylic silicone resin fine particles, the alkoxysilyl group-containing acrylic silicone resin fine particles have the most excellent high-speed film forming property, and are therefore most suitable for rapid image formation. That is, immediately after the recording liquid adheres to the recording medium, the water evaporates or permeates into the recording paper, thereby causing the acrylic silicone resin particles to fuse together. As a result, the alkoxysilyl groups contained in the particles are condensed very quickly by the action of the remaining water, forming a strong siloxane crosslinked film containing the colorant. As a result, high-speed film formation is exhibited. The alkyl of the alkoxysilyl group of the self-crosslinkable acrylic silicone resin fine particles having an alkoxysilyl group is an alkyl having 1 to 3 carbon atoms, and particularly an alkyl having 1 to 2 carbon atoms.
It is preferably an alkyl. Examples of the monomer forming the acrylic skeleton include styrene, vinyl toluene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, vinyl acetate, acrylonitrile, methyl acrylate, and acrylic acid. Ethyl, n-butyl acrylate, 2-ethylhexyl acrylate, methacrylic acid, acrylic acid, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2-acrylic acid
Examples thereof include hydroxyethyl, acrylamide, N-methylolacrylamide, and glycidyl methacrylate. These monomers can be used alone or in combination.

In the present invention, in particular, the use of fluorine resin fine particles as the resin fine particles contained in the recording liquid is advantageous in that this resin has excellent film forming properties, that is, image forming properties, and has a high water repellency inherent to fluororesins. Since it has high water resistance and high weather resistance, it is useful for forming images with high water repellency, high water resistance and high image density. As the fluorine-based resin fine particles, it is particularly useful to use fluorine-based resin fine particles having a fluoroolefin unit. More specifically, fluorine-containing vinyl ether resin fine particles composed of a fluoroolefin unit and a vinyl ether unit can be used effectively. Here, examples of the compound forming the fluoroolefin unit include CF ₂ CF ₂ , CF ₂ CFCF ₃ , CF ₂ CFC
l. Examples of the compound forming a vinyl ether unit include CH ₂ CHOCH ₃ and CH ₂
CHOC ₂ H ₅ , CH ₂ CHOC ₃ H ₇ , CH ₂ CHO
_{C 4 H 9, CH 2 CHOC} 5 H 11, CH 2 CHOCH 2
_{OH, CH 2 CHOC 2 H 4} OH, CH 2 CHOC 3 H
₆ OH, CH ₂ CHOC ₄ H ₈ OH, CH ₂ CHOC ₅
H ₁₀ OH, CH ₂ CHOCH ₂ COOH, CH ₂ CHO
_{C 2 H 4 COOH, CH 2} CHOC 3 H 6 COOH, C
_{H 2 CHOC 4 H 8 COOH,} CH 2 CHOC 5 H 10 C
OOH, CHCH ₃ CHOCH ₃ , CHCH ₃ CHOC
_{2 H 5, CHCH 3 CHOC 3} H 7, CHCH 3 CHO
_{C 4 H 9, CHCH 3 CHOC} 5 H 11, CHCH 3 CH
OCH ₂ OH, CHCH ₃ CHOC ₂ H ₄ OH, CHC
_{H 3 CHOC 3 H 6 OH,} CHCH 3 CHOC 4 H 8 O
_{H, CHCH 3 CHOC 5 H 10} OH, CHCH 3 CHO
_{CH 2 COOH, CHCH 3 CHOC 2} H 4 COOH,
CHCH ₃ CHOC ₃ H ₆ COOH, CHCH ₃ CHO
_{C 4 H 8 COOH, CHCH 3} CHOC 5 H 10 COOH
And so on. Further, as a method of combining these, a combination is preferable in which an alternating copolymer in which fluoroolefin units and vinyl ether units are completely alternately combined is formed.

The average particle size of each resin fine particle used in the present invention is preferably 0.01 μm to 5 μm, more preferably 0.05 μm to 3 μm. When the average particle diameter of the resin fine particles is less than 0.05 μm, the film-forming property is poor, and when it exceeds 5 μm, the optical density (image density) decreases.

Non-film-forming solid fine particles at room temperature which can be used in the present invention (hereinafter simply referred to as "solid fine particles").
May have any composition as long as it is non-film-forming at room temperature and does not contain pigments, dyes, etc., such as inorganic fine particles and synthetic polymer fine particles.

The average particle size of the solid fine particles is 0.05 to 5 μm.
m is desirable. When the average particle diameter is less than 0.05 μm, the coordination effect with the resin fine particles is reduced, and the interaction such as adsorption with the resin fine particles is increased.
The effect on clogging is reduced. Conversely, the average particle size is 5μ
When it is larger than m, when the thickness of the film on the recording paper is thin (5 μm or less), the problem of poor fixing becomes remarkable, for example, solid fine particles cannot be completely taken in the film and easily fall off due to friction or the like. In order to obtain a more favorable effect of preventing clogging without causing these problems, it is desirable that the average particle diameter of the solid fine particles is 0.1 to 2 μm.
The smaller the particle size distribution (standard deviation σ of particle size), the greater the effect on clogging, and the ratio σ / φ to the average particle size φ.
Is preferably 5 or less. If σ / φ is larger than 5, the dispersion stability of the solid fine particles gradually deteriorates, and problems such as deterioration of fixability and uneven density may occur. Therefore, it is further desirable that σ / φ is 3 or less in order to exhibit a more stable effect.

Further, in the present invention, when the solid fine particles have complicated projections or the like, the solid fine particles may aggregate with the surrounding colorant, thereby impairing the color developability or causing density unevenness. Therefore, the shape of the solid fine particles is desirably close to a sphere. Specifically, the shape factor (= L / 2 (πS) ^1/2 × 100, S: area,
(L: perimeter) is preferably 200 or less. More preferably, those having a value of 150 or less are used. Further, as the shape of the solid fine particles is closer to a spherical shape and the particle size distribution is narrower, the dispersion stability in the recording liquid becomes better.

Materials of the inorganic fine particles that can be used as the solid fine particles include aluminum oxide, tin oxide,
Oxides such as zinc oxide, titanium oxide and silicon oxide, silicon nitride and nitrides such as titanium nitride, and silicon carbide;
Any non-water-soluble substance that is solid at room temperature, such as carbides such as tungsten carbide, calcium carbonate, barium sulfate, clay, talc, and mica can be used. These materials can be formed into particles by a method of oxidizing, nitriding, or carbonizing a metal vapor in a gas phase, a method of discharging in a liquid, a spray drying, or a pulverizing method.

Further, as the material of the synthetic polymer fine particles that can be used as the solid fine particles, vinyl chloride resin,
Vinyl acetate resin, polyethylene, polypropylene, polystyrene, ABS resin, fluorine resin, polymethyl methacrylate, acrylic resin, polyisoprene, ethylene propylene rubber, butyl rubber, nitrile rubber, acrylic rubber, silicone rubber, fluorine rubber, nylon, Polycarbonate, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyphenyl sulfide, polysulfone, polyether sulfone, polyether ether ketone, polyarylate, polyimide,
Polymer materials such as polyamide imide, silicone resin, polyurethane, urea resin, phenol resin, melamine resin, polyacetal, and epoxy resin can be used. These resins can be formed into particles by using a polymer polymerization method such as emulsion polymerization, suspension polymerization, or seed polymerization, a suspension aggregation method, or a method of melting a pulverized resin with hot air. Among these, it is preferable to use a method based on polymerization such as emulsion polymerization or suspension polymerization, and resin particles having a narrow particle size distribution and nearly spherical shape can be obtained.

Further, by adjusting the degree of polymerization of these synthetic polymer fine particles, it is possible to control the film forming property at normal temperature. Specifically, when the degree of polymerization is increased, the minimum film formation temperature (MFT) increases. In addition, in the case of a copolymer, the minimum film formation temperature (MFT) can be controlled by adjusting the ratio of the monomers to be copolymerized. The material of the synthetic polymer fine particles that can be used as the solid fine particles may be composed of the same material as the resin fine particles having a film forming property at normal temperature as described above, but the minimum film forming temperature (MFT) is determined by the method described above. ) Must be increased to eliminate the film-forming property at room temperature to make it non-film-forming.

In the present invention, as the solid fine particles, one type of the above-mentioned materials or a mixture of two or more types can be used. Also, these solid fine particles,
It may be obtained in the form of a powder in a gas phase, or may be obtained in a state of being dispersed in an aqueous continuous phase.

Further, in the present invention, the total content of the resin fine particles having film-forming properties and the solid fine particles of non-film-forming properties (the total content of the solid content of the resin fine particles and the solid fine particles) is based on the total amount of the recording liquid. It is preferably from 10 to 95 wt%,
The content is more preferably in the range of 15 to 90 wt%,
More preferably, it is in the range of 0 to 80 wt%. If the content is less than 10 wt%, the optical density of the image will be low, and if it exceeds 95 wt%, the ejection stability will be reduced.

In the present invention, the content of the solid fine particles (the weight of the solid content of the solid fine particles) is preferably 0.5 to 80 wt% based on the solid content of the resin fine particles.
If the proportion of the non-colored solid fine particles is less than 0.5 wt%, the effect of preventing clogging is reduced, and if it exceeds 80 wt%, the dispersion stability in the recording liquid gradually deteriorates. Therefore, it is more preferable that the content of the non-colored solid fine particles (the weight of the solid content of the non-colored solid fine particles) is 1 to 50 wt% based on the solid content of the resin fine particles having film forming properties.

As the colorant in the present invention, pigments, water-soluble dyes, disperse dyes and the like are used, and those having good affinity for water as a main solvent and those having good uniform dispersibility can be used. Can be.

Examples of the pigments usable in the present invention include organic pigments and inorganic pigments. For example, carbon blacks such as furnace black and channel black (C.I. And organic pigments such as aniline black (CI pigment black 1). Further, for color, C.I. I. Pigment Yellow 1, 3, 12, 13,
14, 17, 24, 34, 35, 37, 42, 53, 5
5, 81, 83, 95, 97, 98, 100, 101,
104, 108, 109, 110, 117, 120, 1,
38 and 153, C.I. I. Pigment Violet 1, 3, 5: 1, 16, 19, 23 and 38, C.I.
I. Pigment Blue 1, 2, 15, 15: 1, 15:
Pigments such as 2, 15: 3, 15: 4, 15: 6 and 16. The amount of the pigment added to the total amount of the recording liquid is 1
５０50 wt% is preferable, and furthermore, 1.5-40 w
t% is preferred. In order to disperse these pigments more evenly, dispersion treatment may be performed by a ball mill or the like in some cases.

Examples of the water-soluble dye that can be used in the present invention include direct dyes and acid dyes.
C. I. Direct Black 9, 17, 19, 22, 3
2, 51, 56, 62, 69, 77, 80, 91, 9
4, 97, 108, 112, 113, 114, 117,
118, 121, 122, 125, 132, 146, 1
54, 166, 168, 173 and 199, C.I. I.
Direct violet 7, 9, 47, 48, 51, 6
6, 90, 93, 94, 95, 98, 100 and 10
1, C.I. I. Direct Yellow 8, 9, 11, 12,
27, 28, 29, 33, 35, 39, 41, 44, 5
0, 53, 58, 59, 68, 86, 87, 93, 9
5, 96, 98, 100, 106, 108, 109, 1
10, 130, 132, 144, 161, and 163;
C. I. Direct Blue 1, 10, 15, 22, 2
5, 55, 67, 68, 71, 76, 77, 78, 8
0, 84, 86, 87, 90, 98, 106, 201,
202, 244, 251 and 280, C.I. I. Acid Black 7, 24, 29 and 48, C.I. I. Acid Violet 5, 34, 43, 47, 48, 90 and 103, C.I. I. Acid Yellow 17, 19, 2
3, 25, 39, 40, 44, 49, 50, 61, 11
0, 174 and 218, C.I. I. Acid blue 9,
25, 40, 41, 62, 72, 76, 80, 106,
112, 120, 205, 230, 271 and 280
And the like, but are not limited to these.
The amount of these dyes to be added is determined depending on the type of the dye, the type of the solvent component, the properties required for the recording liquid, and the like. 4
0 wt%, preferably in the range of 0.5 to 30 wt%.

Further, the recording liquid of the present invention may contain, if necessary, a pH adjuster such as potassium dihydrogen phosphate and sodium dihydrogen phosphate, and benzoic acid, diclofen for the purpose of fungicidal, antiseptic and rustproofing. , Hexachlorophene, sorbitanic acid and the like can be added. If necessary, various general additives such as ethylene glycol and glycerin may be added to the recording liquid.

The production of the recording liquid can be performed according to the following procedure, but is not limited thereto. The aqueous dispersion of the colorant was dispersed in a ball mill, and it was confirmed by microscopic observation that the colorant particles were in a monodispersed state.To the dispersion, resin fine particles dispersed in water were added, and the mixture was stirred and uniformly mixed. To mix. Then, add powdery solid fine particles,
Stir at 3000 rpm for 10 minutes with a homogenizer to disperse the solid particles. Further, after adding additives such as a preservative and confirming complete dissolution, the obtained dispersion was subjected to pore size 1 addition.
Filtration through a 0 μm membrane filter removes dust and coarse particles to obtain a recording liquid. As a method for dispersing the solid fine particles, in addition to the method described above, a dispersion of solid fine particles in a dispersion medium mainly containing water may be added and mixed. In this case, an ionic surfactant, a nonionic surfactant, a polymer dispersant, or the like may be added as the dispersing agent to disperse.

The recording liquid of the present invention can be used in an image recording method in which droplets are ejected from a head to perform recording on a recording medium such as paper, and can also be used as a writing implement, printing, and stamping ink. Can also.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. Example 1 As resin fine particles, self-crosslinkable resin fine particles of an acrylic silicone resin having a hydrolyzable methoxysilyl group dispersed in water, non-colored solid fine particles of polymethyl methacrylate, and copper phthalocyanine as a colorant An aqueous dispersion of a pigment (Pigment Blue 15: 3) was mixed at the following mixing ratio to prepare a recording liquid. 66 parts by weight of acrylic silicone resin fine particle dispersion (SW-135, manufactured by Sanyo Chemical Industries, solid content = 35 wt%) 2 parts by weight of non-colored solid fine particles (MP-2200, manufactured by Soken Chemical Co., average particle diameter 0.4 μm) Copper phthalocyanine pigment (Pigment Blue 15: 3) Aqueous dispersion (EP-700 manufactured by Dainichi Seika Kogyo, solid content = 34.7 wt%) 32 parts by weight Resin / solid fine particle ratio = solid fine particles / (resin solid content + solid fine particles) × 100 = 10 wt% pigment (colorant) concentration in solid content = pigment solid content / (resin solid content + solid fine particles + pigment solid content) x 100 = 30 wt% total solid content concentration in recording liquid = (resin solid content + solid fine particles + Pigment solid content) ÷ Total amount of recording liquid × 100 = 36.4 wt% Pigment (colorant) concentration in recording liquid = Pigment solid content ÷ Total amount of recording liquid × 100 = 10.9 wt%

The recording liquid prepared as described above is coated on plain paper for a copying machine (L paper, WR paper, J paper manufactured by Fuji Xerox Co., Ltd.) using a bar coater and dried at room temperature (25 ° C.). As a result, a solid image consisting of a coating and dried film was obtained on plain paper. The optical density of the obtained image (Opt
ical density) was measured. Image area 1c
The optical density of a solid image applied with a small amount of recording liquid of 0.9 mg per m ² was measured using a reflection densitometer X-Rite404.
As a result of the measurement at an average of 5 points, the optical density was 1.6 or more in any of the papers, indicating that a high optical density was obtained. Observation of the longitudinal section of the solid image on the plain paper with an optical microscope revealed that the solid image was mainly formed on the plain paper, and that the recording liquid hardly penetrated into the plain paper.

In order to test the fixability of this recording liquid, 3
Plain paper (L paper manufactured by Fuji Xerox Co., Ltd.) was superimposed on the solid image coated surface prepared under the above-described conditions on a kind of plain paper, and a pen offset test was performed. A straight line having a length of 5 cm was drawn from the stacked plain paper with an Eriksen 318 test bar set at a writing pressure of 300 g, and a portion which was in close contact with the coated surface of the stacked plain paper was magnified and observed. As a result, in the solid image which was left at room temperature (25 ° C.) for 30 seconds or more after the application of the recording liquid, no adhesion of the recording liquid to the superposed paper was observed at all, and the film on the applied surface did not peel off. Furthermore, the solid images prepared on three types of plain paper under the same conditions were tested for the peeling of the recording liquid by rubbing with a finger. As a result, the peeling of the recording liquid and the adhesion of the recording liquid to the finger were observed in all samples. No occurrence was observed, and it was confirmed that the toner had excellent fixability.

In order to examine the water resistance performance of this recording liquid,
I rubbed the coated surface prepared with the method described above with a finger with distilled water, and found that there was no sticking of the recording liquid to the finger, seepage of the recording liquid into the paper, and no bleeding at the boundary with the non-coated part. Did not occur. Further, solid images prepared on three types of plain paper under the above conditions were cut into squares each measuring 2 cm on a side, and these were immersed in 50 ml of distilled water in a petri dish at room temperature (25 ° C.).
For 24 hours. Thereafter, these samples were taken out, dried at room temperature for 8 hours, and the above-described pen offset test was performed on the coated surface. As a result, the recording liquid was applied to the portion of the stacked plain paper which was in close contact with the coated surface. Was not observed at all. The optical densities of the three types of plain paper samples left for 24 hours show an optical density of 1.6 as measured by the reflection densitometer X-Rite 404 described above.
It was confirmed that there was no problem with water resistance.

Next, the clogging property of the recording liquid at the discharge port of the recording head was evaluated by the following method. A standard syringe needle (manufactured by Iwashita Engineering Co., Ltd.) having an inner diameter of 180 μm was set at the tip of a syringe having an inner diameter of 15 mm, and a fixed amount of 10 ml (milliliter) of the recording liquid was sucked into the syringe. By opening or closing the upper part of the syringe, dripping or non-dripping (stopping) of the recording liquid from the injection needle was controlled. The specific evaluation method of the clogging property by this experimental method is as follows. First, the upper part of the syringe is sealed, and the dripping of the recording liquid from the injection needle is stopped. Then, after a certain period of elapse, the upper part was opened, and it was measured and evaluated whether or not the recording liquid could be continuously dropped from the injection needle. The maximum rest time (maximum leaving time) of the recording liquid that can be dropped from the injection needle was set as a margin time until the occurrence of clogging. The margin time until the clogging of the recording liquid measured as described above was as long as 25 seconds.

Next, a printing test of this recording liquid on plain paper was performed using a commercially available ink jet printer. As a result, stable ejection was possible in the state of a stock solution not diluted with water. Observation of the printed dots of the sample printed as described above using a magnifying loupe and an optical microscope showed that clear dots with no image liquid bleeding around the dots and high image density were formed. confirmed.

Example 2 Modified polyester resin fine particles having carboxyl groups added to side chains dispersed in water as fine resin particles, and polymethyl methacrylate fine particles as non-colored solid fine particles,
Further, an aqueous dispersion of a copper phthalocyanine pigment (Pigment Blue 15: 3) as a coloring agent was mixed at the following mixing ratio to prepare a recording liquid. 70 parts by weight of non-colored solid fine particles (MP-2200 manufactured by Soken Chemical Co., Ltd., average particle diameter 0.4 μm) 2 parts by weight of copper phthalocyanine pigment ( Pigment Blue 15: 3) Aqueous dispersion (EP-700, manufactured by Dainichi Seika Kogyo, solid content = 34.7 wt%) 28 parts by weight Resin / solid fine particle ratio = solid fine particles ÷ (resin solid content + solid fine particles) × 100 = 10% by weight Pigment (colorant) concentration in solid content = Pigment solid content ÷ (Resin solid content + solid fine particles + pigment solid content) × 100 = 30 wt% Total solid content concentration in recording liquid = (Resin solid content + solid fine particles + pigment) (Solid content) ÷ total amount of recording liquid × 100 = 32.8 wt% concentration of pigment (colorant) in recording liquid = pigment solid content ÷ total amount of recording liquid × 100 = 9.8 wt%

Using a bar coater, 0.9 mg of the recording liquid prepared as described above was coated on plain paper for a copying machine (L paper, WR paper, J paper manufactured by Fuji Xerox Co., Ltd.) in an image area of 1 cm ² . The recording liquid was applied in an applied amount and dried at room temperature (25 ° C.) to obtain a solid image formed of a coated and dried film on plain paper. Then, the optical density of the obtained image was measured by the same method as in Example 1. As a result, a value of 1.5 or more was obtained for any paper, and a high optical density was obtained. Further, as a result of observing the longitudinal section of the solid image on the plain paper with an optical microscope, almost no permeation of the recording liquid into the plain paper was recognized.

The fixing properties of the recording liquid were tested in the same manner as in Example 1 (pen offset test, finger friction test). As a result, the recording liquid was peeled off on all three types of plain paper. No problem such as adhesion of the recording liquid to the finger occurred at all, and it was confirmed that the fixability was excellent. As a result of testing the water resistance performance of this recording liquid in the same manner as in Example 1, there was no problem with water resistance in both the friction test of the coated surface with a wet finger and the 24-hour water immersion test. It was confirmed that there was no.

Next, the clogging property of the recording liquid at the discharge port of the recording head was tested in the same manner as in Example 1. As a result, the margin time until the clogging of the recording liquid was as long as 20 seconds or more. Was. Next, a printing test of the recording liquid on plain paper was performed using a commercially available inkjet printer, and as a result, stable ejection was possible even in an actual machine.
Observation of the printed dots of the printed sample with a magnifying loupe and an optical microscope confirmed that clear dots with no image liquid bleeding around the dots and high image density were formed.

Example 3 As resin fine particles, fluororesin fine particles made of a fluorinated vinyl ether resin produced by emulsion polymerization of a copolymer of fluoroolefin and vinyl ether dispersed in water, and polymethacrylic acid as non-colored solid fine particles A recording liquid was prepared by mixing methyl fine particles and an aqueous dispersion of a copper phthalocyanine pigment (Pigment Blue 15: 3) as a coloring agent in the following mixing ratio. Fluororesin fine particle dispersion (FE-3000 manufactured by Asahi Glass; solid content = 50 wt%) 58 parts by weight Non-colored solid fine particles (MP-2200 manufactured by Soken Chemical, average particle diameter 0.4 μm): 3 parts by weight Copper phthalocyanine pigment (pigment) Blue 15: 3) Aqueous dispersion (EP-700 manufactured by Dainichi Seika Industries, solid content = 34.7 wt%) 39 parts by weight Resin / solid fine particle ratio = solid fine particles / (resin solid content + solid fine particles) × 100 = 10 wt % Pigment (colorant) concentration in solid content = pigment solid content / (resin solid content + solid fine particles + pigment solid content) × 100 = 30 wt% Total solid content concentration in recording liquid = (resin solid content + solid fine particles + pigment solid) Min) ÷ total amount of recording liquid × 100 = 45.4 wt% pigment (colorant) concentration in recording liquid = solid pigment content ÷ total amount of recording liquid × 100 = 13.6 wt%

Using a bar coater, 0.9 mg of the recording solution prepared as described above was coated on plain paper for a copying machine (L paper, WR paper, J paper manufactured by Fuji Xerox Co., Ltd.) in an image area of 1 cm ² . The recording liquid was applied in an applied amount and dried at room temperature (25 ° C.) to obtain a solid image formed of a coated and dried film on plain paper. Then, the optical density of the obtained image was measured by the same method as in Example 1. As a result, a value of 1.5 or more was obtained for any paper, and a high optical density was obtained. Further, as a result of observing the longitudinal section of the solid image on the plain paper with an optical microscope, almost no permeation of the recording liquid into the plain paper was recognized.

The fixing properties of the recording liquid were tested in the same manner as in Example 1 (pen offset test, finger friction test). As a result, the recording liquid was peeled off on all three types of plain paper. No problem such as adhesion of the recording liquid to the finger occurred at all, and it was confirmed that the fixability was excellent. As a result of testing the water resistance performance of this recording liquid in the same manner as in Example 1, there was no problem with water resistance in both the friction test of the coated surface with a wet finger and the 24-hour water immersion test. It was confirmed that there was no.

Next, the clogging property of the recording liquid at the discharge port of the recording head was tested in the same manner as in Example 1. As a result, the margin time until the clogging of the recording liquid was as long as 20 seconds or more. Was. Furthermore, a printing test of the recording liquid on plain paper was performed using a commercially available ink jet printer. As a result, stable ejection was possible even in an actual machine. Observation of the printed dots of the printed sample with a magnifying loupe and an optical microscope confirmed that clear dots with no image liquid bleeding around the dots and high image density were formed.

Example 4 Acrylic silicone resin fine particles having a hydrolyzable methoxysilyl group as fine resin particles, silica fine particles as non-colored solid fine particles, and a copper phthalocyanine pigment (Pigment Blue 15: 3) aqueous solution as a colorant The recording liquid was prepared by mixing the dispersion with the following mixture ratio. Acrylic silicone resin fine particle dispersion (SW-135 manufactured by Sanyo Chemical Industries, solid content = 35 wt%) 66 parts by weight Non-colored solid fine particles (Nippon Shokubai KE-P50, average particle size 0.5 μm) 2 parts by weight Copper phthalocyanine pigment ( Pigment Blue 15: 3) Aqueous dispersion (EP-700 manufactured by Dainichi Seika Industries, solid content = 34.7 wt%) 32 parts by weight Resin / solid fine particle ratio = solid fine particles ÷ (resin solid content + solid fine particles) × 100 = 10% by weight Pigment (colorant) concentration in solid content = Pigment solid content ÷ (Resin solid content + solid fine particles + pigment solid content) × 100 = 30 wt% Total solid content concentration in recording liquid = (Resin solid content + solid fine particles + pigment) Solid content) ÷ total amount of recording liquid × 100 = 36.4 wt% concentration of pigment (colorant) in recording liquid = pigment solid content ÷ total amount of recording liquid × 100 = 10.9 wt%

Using a bar coater, 0.9 mg of the recording solution prepared as described above was coated on plain paper for a copying machine (L paper, WR paper, J paper manufactured by Fuji Xerox Co., Ltd.) per 1 cm ^{2 of} image area. The recording liquid was applied in an applied amount and dried at room temperature (25 ° C.) to obtain a solid image formed of a coated and dried film on plain paper. Then, the optical density of the obtained image was measured by the same method as in Example 1. As a result, a value of 1.5 or more was obtained for any paper, and a high optical density was obtained. Further, as a result of observing the longitudinal section of the solid image on the plain paper with an optical microscope, almost no permeation of the recording liquid into the plain paper was recognized.

The fixing properties of the recording liquid were tested in the same manner as in Example 1 (pen offset test, finger friction test). As a result, the recording liquid was peeled off on all three types of plain paper. No problem such as adhesion of the recording liquid to the finger occurred at all, and it was confirmed that the fixability was excellent. As a result of testing the water resistance performance of this recording liquid in the same manner as in Example 1, there was no problem with water resistance in both the friction test of the coated surface with a wet finger and the 24-hour water immersion test. It was confirmed that there was no.

Next, the clogging property of the recording liquid at the discharge port of the recording head was tested by the same method as in Example 1. As a result, the margin time until the clogging of the recording liquid was 20 seconds or more was sufficiently long. there were. Further, a printing test of the above recording liquid on plain paper was performed using a commercially available ink jet printer, and as a result, stable discharge was possible with an actual machine. Observation of the printed dots of the printed sample with a magnifying loupe and an optical microscope confirmed that clear dots with no image liquid bleeding around the dots and high image density were formed.

Comparative Example For the purpose of comparing the effects of the present invention, the recording liquids obtained by removing non-colored solid fine particles from the recording liquids of Examples 1 to 3 were adjusted so that the pigment concentration in the solid content was equal to that in Example 1. Created in
An evaluation was performed. The composition of the recording liquid is shown below.

Comparative Example 1 Acrylic silicone resin fine particle dispersion (SW-135 manufactured by Sanyo Chemical Industries, solid content = 35 wt%) 70 parts by weight Copper phthalocyanine pigment (pigment blue 15: 3) aqueous dispersion (manufactured by Dainichi Seika Kogyo) (EP-700, solid content = 34.7 wt%) 30 parts by weight Pigment (colorant) concentration in solid content = pigment solid content / (pigment solid content + resin fine particle solid content) × 100 = 30 wt% total solid content in recording liquid Concentration = (pigment solid content + resin fine particle solid content) ÷ total amount of recording liquid x 100 = 34.9 wt% Pigment (colorant) concentration in recording liquid = pigment solid ÷ total amount of recording liquid x 100 = 10.5 wt%

Comparative Example 2 Modified polyester resin fine particle dispersion (A-215G manufactured by Takamatsu Oil & Fat Co., solid content = 30 wt%) 73 parts by weight Copper phthalocyanine pigment (pigment blue 15: 3) aqueous dispersion (EP manufactured by Dainichi Seika Kogyo Co., Ltd.) -700, solid content = 34.7 wt%) 27 parts by weight Pigment (colorant) concentration in solid content = pigment solid content / (pigment solid content + resin fine particle solid content) × 100 = 30 wt% Total solid content concentration in recording liquid = (Pigment solid content + resin fine particle solid content) ÷ total amount of recording liquid x 100 = 31.3 wt% Pigment (colorant) concentration in recording liquid = pigment solid content 全 total amount of recording liquid x 100 = 9.4 wt%

Comparative Example 3 Fluorine resin fine particle dispersion (FE-3000 manufactured by Asahi Glass; solid content = 50 wt%) 62 parts by weight Copper phthalocyanine-based pigment (pigment blue 15: 3) aqueous dispersion (EP-700 manufactured by Dainichi Seika Kogyo) 38% by weight Pigment (colorant) concentration in solid content = Pigment solid content / (Pigment solid content + Resin fine particle solid content) × 100 = 30% by weight Total solid content concentration in recording liquid = ( (Pigment solid content + resin fine particle solid content) ÷ Total amount of recording liquid × 100 = 44.2 wt% Pigment (colorant) concentration in recording liquid = Pigment solid content 全 Total amount of recording liquid × 100 = 13.2 wt%

The recording liquid prepared as described above was applied to a plain paper for a copying machine (L paper, WR paper, J paper manufactured by Fuji Xerox Co., Ltd.) using a bar coater in the same manner as in Example 1 to obtain an image area of 1 cm. ^The coating liquid was applied at a coating amount of 0.9 mg per ² and dried at room temperature (25 ° C.) to obtain a solid image composed of a coating and dried film on plain paper. The optical density of the obtained image was measured by the same method as in Example 1. As a result, in each of Comparative Examples 1, 2, and 3, all the papers showed an optical density of 1.5 or more. In addition, as a result of observing the longitudinal section of these solid images on plain paper with an optical microscope,
Almost no permeation of the recording liquid into plain paper was observed.

Next, the clogging of the recording liquid at the recording head discharge port was tested in the same manner as in Example 1. The margin time until clogging of the recording liquid of each comparative example was 8 in Comparative Example 1.
Second, Comparative Example 2 was 5 seconds, and Comparative Example 3 was 5 seconds, all of which were extremely shorter than those of the examples.

Further, a printing test on plain paper was carried out by using a commercially available ink-jet printer in the same manner as in Example 1, using the recording liquids of these comparative examples. As a result, the time until printing was impossible due to clogging was 10 seconds in Comparative Example 1, 5 seconds in Comparative Example 2, and 5 seconds in Comparative Example 3, which were extremely shorter than those in Examples. Was.
In each case, cleaning was performed, but did not return to the initial state. When the nozzle portion of this head was observed under magnification with a microscope, it was found that the recording liquid was dried and fixed at all nozzle outlets.

[0061]

As described above, in the recording liquid of the present invention, due to the action of the solid resin fine particles, the approach of the resin fine particles in the recording liquid causes clogging at the head ejection port due to collision and fusion. It is possible to inhibit the cause of occurrence. Therefore, it can be used as a recording liquid for an ink jet printer which is excellent in ejection stability without clogging. Further, when the recording liquid of the present invention is used, a film containing a high-density colorant without bleeding or permeation is formed on the surface of the recording medium, and an image having a high image density (optical density) can be recorded. Further, a film having a high solid content containing a colorant on the surface of the recording medium has excellent fixability and water resistance. As a result, high image density of the film of the recording liquid, and thereby high image quality, and prevention of clogging can be simultaneously achieved.

Claims (2)

[Claims] Claims: 1. A fine particle comprising water, a colorant, resin fine particles capable of forming a film at normal temperature, and solid fine particles which are water-insoluble and non-film forming at a normal temperature, wherein the solid fine particles are inorganic fine particles and / or synthetic polymer fine particles. A recording liquid, characterized in that: 2. An image recording method in which recording liquid droplets are ejected from a head to perform recording on a recording medium, wherein the recording liquid according to claim 1 is used as the recording liquid.