JP2006045511A - Water-based ink, ink tank, apparatus for inkjet recording, method for inkjet recording and inkjet recorded image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based ink comprising a dispersible colorant having sufficiently high dispersion stability without separating a resin component from the colorant and forming a recorded image having glossiness and high image quality and to provide an ink tank, an apparatus for inkjet recording, a method for inkjet recording and an inkjet recorded image by using the water-based ink. <P>SOLUTION: The water-based ink is characterized as follows. The water-based ink comprises the dispersible colorant and at least one selected from a water-soluble nonionic resin and emulsion particles.The dispersible colorant has the colorant and chargeable resin pseudo-fine particles smaller than the colorant. In the dispersible colorant, the colorant and the chargeable resin pseudo-fine particles are fixed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aqueous ink, an ink jet recording apparatus, an ink jet recording method, and an ink jet recorded image containing a dispersible colorant and a water-soluble nonionic resin or emulsion particles.

  The ink jet method is a method for recording images, characters, etc. by causing a micro droplet of ink to fly from a nozzle to reach a recording medium (paper, etc.) based on various operating principles. It is easy to realize, has high flexibility in recording patterns, and does not require development and fixing operations, and is rapidly spreading in various applications. In particular, in recent years, full-color water-based inkjet recording technology has been remarkably developed, and it is possible to form multicolored images that are comparable to multicolored printing by conventional platemaking methods and printing by color photographic methods. In the case where the number of copies to be produced is small, printed matter can be obtained at a lower cost than ordinary multicolor printing or printing, so that it has been widely applied to the field of full-color image recording.

  In response to demands for further improvement in recording characteristics such as higher recording speed, higher definition, and full color, improvements in aqueous inkjet recording apparatuses and recording methods have been made. In general, the performance required for water-based ink used in an ink jet recording apparatus is as follows: (1) A uniform image with high resolution and high density without blurring or fogging can be obtained on paper (2). Clogging due to drying of ink at the nozzle tip does not occur, ejection response and ejection stability are always good, (3) ink fixability is good on paper, and (4) weather resistance of the image. (5) long-term storage stability is good. In particular, with the recent increase in printing speed, there has been a demand for ink that can quickly dry and fix the ink and obtain high-quality recording.

  The coloring materials used in the water-based inkjet recording method mainly include dyes and pigments. Conventionally, water-soluble dyes have been mainly used due to their ease of handling as water-based inks and high color developability. As a coloring material for water-based inkjet recording ink that can realize high weather resistance of an image, development of a coloring material that is essentially insoluble in water, particularly an ink using a pigment, has been energetically advanced. In order to use a water-insoluble colorant, particularly a pigment, as an aqueous inkjet recording ink, it is necessary to stably disperse the colorant in water.

  In this case, generally, a method of stabilizing the dispersion using a surfactant or a polymer dispersant (hereinafter also referred to as a dispersion resin) has been used. Further, a method for chemically modifying the surface of the water-insoluble colorant has been proposed (see, for example, Patent Document 1). In addition, a microcapsule type pigment in which the pigment is coated with a resin has been proposed (see, for example, Patent Documents 2 and 3). In particular, in Patent Document 3, “in a water-based colored fine particle dispersion containing a water-insoluble colorant, the colored fine particle dispersion disperses the water-insoluble colorant in an aqueous medium in the presence of the dispersant, and then the vinyl monomer is added. A latex that is added and polymerized, exhibits dispersion stability when the dispersant is dispersed with a water-insoluble colorant, and is formed when the vinyl monomer is polymerized in the presence of the dispersant alone. A water-based colored fine particle dispersion characterized by poor stability of the polymer "is disclosed, and when the emulsion polymerization is carried out into a water-insoluble colorant dispersion, the affinity of the dispersant to the vinyl monomer and the resulting polymer is not much. Because it is not high, desorption of the dispersant from the pigment surface is unlikely to occur, and polymerization has proceeded on the pigment surface to which the dispersant has been adsorbed, ”“ aggregating the fine particle dispersion coated with the pigment surface ” By using the colored fine particle dispersion, it is excellent in dispersion stability and printability, is not dependent on the paper type, has little metallic luster, water resistance, light resistance, It is said that a water-based ink that gives an image excellent in scratch resistance is obtained.

Japanese Patent Laid-Open No. 10-195360 JP-A-8-183920 JP 2003-34770 A

  However, with the above-described technique, there are cases where the dispersion stability of the color material and the gloss of the recorded image are not sufficient. According to the study by the present inventors, it is necessary to increase the surface functional group density of the colorant in order to increase the dispersion stability. However, the conventional technique using a polymer dispersant and the above-mentioned Patent Document 2 In the method of making the pigment coated with the resin shown in the above, if the acid value of the resin is increased in order to increase the dispersion stability, the hydrophilicity of the resin also increases. Therefore, long-term storage stability may not be maintained. On the other hand, in the method of chemically modifying the surface of the water-insoluble colorant by the method disclosed in Patent Document 1, there is a limit to the functional group that can be modified and its density, and the colorant is particularly an organic pigment. In some cases, direct chemical modification causes pigment molecules that are originally insoluble in water and crystallized to become water-soluble due to the binding of hydrophilic groups and to dissolve out of the pigment particles. The technical level is not sufficiently satisfactory, such as the problem of significant change (see FIGS. 6A and 6B).

  The object of the present invention is to solve these problems of the prior art, and to provide glossiness comprising an excellent dispersible colorant having sufficiently high dispersion stability and no detachment of the resin component from the colorant. It is an object of the present invention to provide a water-based ink capable of forming a high-quality image. Furthermore, another object of the present invention is to provide an ink tank, an ink jet recording apparatus, an ink jet recording method, and an ink jet recorded image using such aqueous ink.

  On the other hand, as a result of intensive investigations on means for solving the above problems, the present inventors have achieved a high dispersion stability and a resin component is removed from the color material by using a dispersible color material having a novel shape. We have developed a new dispersible colorant that has long-term storage stability without being separated. And by using such dispersible color material, it has sufficient ejection stability and dispersion stability for inkjet recording applications, and further, by containing at least one selected from water-soluble nonionic resin and emulsion particles, it is high. A water-based ink giving a printed matter with excellent image quality was obtained. The object of the present invention is achieved by the following specific means.

  That is, the present invention provides a dispersible color material having a color material and a chargeable resin pseudo fine particle smaller than the color material, and the color material and the charge resin pseudo fine particle are fixed, and a water-soluble material. A water-based ink comprising at least one selected from nonionic resins and emulsion particles.

  The present invention also provides an ink tank comprising the above water-based ink.

  According to another aspect of the present invention, there is provided an ink jet recording apparatus which forms an ink jet recording image using the water-based ink.

  According to another aspect of the present invention, there is provided an ink jet recording method, wherein an image is formed by an ink jet recording apparatus using the water-based ink.

  The present invention is also an ink jet recording image formed by an ink jet recording apparatus using the water-based ink.

  According to the present invention, there is provided a water-based ink in which a recorded image obtained particularly when recorded on a glossy recording medium is excellent in gloss and has excellent dispersion stability. As another effect of the present invention, there are provided an ink tank, an ink jet recording apparatus, an ink jet recording method, and an ink jet recorded image which can give an image having excellent glossiness by using the above excellent ink.

  Hereinafter, the present invention will be described in detail with reference to an embodiment which is considered to be the best of the present invention. The term “dispersible colorant” used in the present specification and claims means that it can be dispersed in water or an aqueous ink medium without essentially adding a surfactant or a polymer dispersant. That is, it is a color material having self-dispersibility.

  First, the dispersible color material used in the ink according to the present invention is a dispersible color material having a color material and chargeable resin pseudo fine particles smaller than the color material, the color material and the chargeable color material. The resin pseudo fine particles are fixed. In particular, the color material is preferably one in which a plurality of the chargeable resin pseudo fine particles are scattered and fixed to the color material.

  The first characteristic of the dispersible color material used in the present invention is a dispersible color material comprising a color material and a chargeable resin pseudo fine particle, and the color material fixes the chargeable resin pseudo fine particle. There is in point. FIG. 1 is a schematic diagram of a dispersible color material, which characterizes the present invention, in which chargeable resin pseudo fine particles 2 are fixed to a color material 1. A portion 2 ′ in FIG. 1B is a portion schematically showing a state in which a part of the chargeable resin pseudo fine particles 2 fixed to the surface of the color material 1 is fused.

  By fixing the chargeable resin pseudo fine particles to the color material, the charge of the chargeable resin pseudo fine particles is imparted to the surface of the color material, so that the dispersible color material can be dispersed in water or an aqueous ink medium. At the same time, the dispersible colorant has excellent adhesion to the recording medium due to the presence of the resin component adhering to the surface. At this time, since the chargeable resin pseudo fine particles, which are the characteristic of the dispersible color material used in the present invention, are not in a simple physical adsorption of the resin component, the charge resin pseudo fine particles are fixed to the color material. There is no detachment from the color material surface. For this reason, when the dispersible color material used in the present invention is used as an ink color material, the long-term storage stability is also excellent.

  Here, the chargeable resin pseudo fine particles in the present invention are resin aggregates in which the resin component is strongly aggregated, and preferably have many physical crosslinks formed therein (resin aggregates and Is a resin component having a stable form as a fine particle form or a microaggregate close to it). Details of the chargeable resin pseudo fine particles will be described later.

  The state where the chargeable resin pseudo fine particles are fixed to the color material in the present invention is due to the strong interaction between the color material surface and the chargeable resin pseudo fine particles, and is considered to be achieved in the following state. FIG. 4 shows a schematic diagram in which the interface of the chargeable resin pseudo fine particles in contact with the color material is enlarged. First, the chargeable resin pseudo fine particles 2 are formed by intertwining polymers composed of various monomer unit compositions (indicated by 9-1 and 9-2 in the figure). Since the polymer has various structures locally at the interface with the colorant, various states are distributed in the local surface energy. The color material and the polymer are strongly bonded in that the surface energy generated from the chemical structure and the surface structure of the color material and the surface energy generated from the chemical structure and the surface structure of the polymer are well matched locally. (The part indicated by a black circle in the figure). Furthermore, as shown in FIG. 4, there are a plurality of points where the surface energies of both are locally coincident with each other at the interface where one chargeable resin pseudo fine particle is in contact with the coloring material. It is expected that the fixed state of the present application is established by the strong interaction at the plurality of locations. In the present invention, a state in which, for example, 30% or more of the surface area of the chargeable pseudo fine particles, such as 2 ′ in FIG. 1B, is in contact with the coloring material is referred to as “fusion” for convenience. Is a form of fixation, and there is no need for the chargeable pseudo fine particles and the color material to melt together at the interface.

  In particular, a strong interaction is exerted between constituent polymers inside the chargeable resin pseudo fine particles, and in some cases, the constituent polymers are entangled with each other to form a physical crosslink. For this reason, even when the chargeable resin pseudo fine particles have many hydrophilic groups, the fixed charge resin pseudo fine particles are detached from the coloring material or have hydrophilic groups from the chargeable resin pseudo fine particles. The resin component does not continue to elute. On the other hand, in the encapsulation method as described in Patent Document 2, since the highly hydrophilic resin cannot be strongly bonded to the coloring material, the resin is detached from the coloring material, and as a result, the long-term storage stability is sufficient. It may not be obtained.

  In addition, the dispersible color material used in the present invention has a merit that the chargeable resin pseudo fine particles are fixed to the color material. As a result, the specific surface area of the dispersible color material increases depending on the form, and much of the color material surface It is mentioned that the charge of the chargeable resin pseudo fine particles can be distributed on the surface. As a result of the high specific surface area of the dispersible color material, the charge of the chargeable resin pseudo fine particles can be converted to the surface charge of the dispersible color material with extremely high efficiency. That is, the form of the dispersible color material used in the present invention is a form in which more surface charges are more efficiently arranged on the surface of the dispersible color material. High dispersion stability can be imparted even when the substantial acid value or amine value of the resin component is smaller than in the form of coating with a resin.

  In general, organic pigments are insolubilized (pigmented) by crystallization of coloring material molecules by strong interaction. In the case of a dispersible color material in which the color material used in the present invention is an organic pigment, as described above, a plurality of interaction points are distributed at the interface between the chargeable resin pseudo fine particles and the color material. The functional resin pseudo fine particles 11 are fixed across several colorant molecules 1a in the pigment particles (see FIG. 5). Therefore, the “pigment peeling” caused by locally hydrophilizing the colorant molecule 1a by the hydrophilic group 12 as described in FIGS. 6A and 6B does not occur in the present invention. Preferably, when an organic pigment is used as a color material, the size of the chargeable resin pseudo fine particles is controlled to be within a range smaller than the dispersed particle diameter of the pigment and larger than the color material molecule. An organic pigment dispersible colorant imparted with high dispersibility without breaking the crystal structure can be obtained.

  In the present invention, the state in which the coloring material “fixes” the chargeable resin pseudo fine particles can be simply confirmed by a technique involving the following three stages of separation. First, in the first separation, the color material to be confirmed is separated from other water-soluble components (including water-soluble resin components) contained in the ink or water dispersion, and then the second In the separation, the coloring material and the water-insoluble resin component contained in the precipitate in the first separation are separated. Furthermore, in the third separation, the weakly adsorbed resin component is separated from the dispersible colorant fixing the charged resin pseudo fine particles, and the quantitative determination of the resin component contained in the third separation supernatant, Then, the fixation of the coloring material and the chargeable resin pseudo fine particles is confirmed by comparing the precipitate of the second separation and the precipitate of the third separation.

  Specifically, for example, it can be confirmed under the following conditions. Take 20 g of the ink or water dispersion in which the color material is dispersed, adjust the total solid content to about 10%, and use a centrifuge to perform the first test at 12,000 rpm for 60 minutes. Separation. Of the separated substances, the lower sediment containing the coloring material is redispersed in pure water approximately three times the amount of the sediment, and then the second sediment is obtained at 80,000 rpm for 90 minutes. Perform separation. The lower layer containing the color material is subjected to the third separation again under the condition of 80,000 rotations and 90 minutes by redispersing the sediment of the lower layer containing the color material in 3 times the amount of pure water. Remove the sediment. The sediment in the second separation and the sediment in the third separation were each taken to have a solid content of about 0.5 g and dried under reduced pressure at 30 ° C. for 18 hours using a scanning electron microscope. Observe at 50,000 times. Then, it was confirmed that the observed dispersible colorant had a plurality of fine particle-like substances or fine aggregates equivalent thereto attached to the surface, and the respective sediments from the second separation and the third separation. If it has the same form, it is judged that this coloring material has fixed the resin pseudo fine particles. Further, the upper layer supernatant in the third separation is gently taken from the top so as to be about half the volume, and the solid content mass is calculated from the mass change before and after drying at 60 ° C. for 8 hours. If it is less than 1%, it is considered that the resin pseudo fine particles are not detached from the dispersible color material, and it can be determined that the dispersible color material fixes the resin pseudo fine particles.

  The above-described separation conditions are preferable examples, and any other separation method or separation condition can be used as long as the method achieves the purpose of the first separation and the second and third separations described above. It can be applied as a method for determining whether or not it is a dispersible colorant used in the above. That is, the first separation is for the purpose of separating the color material contained in the ink and water dispersion and the resin component adsorbed thereto, and the water-soluble component, and the second separation is the color material. The purpose is to separate the resin component adhering to the coloring material and the other resin component adsorbing to the coloring material. Furthermore, the third separation is intended to confirm that the resin component adhering to the color material is not detached. Of course, as long as the separation method achieves the respective purposes of the first, second, and third separations, any other separation method that is publicly known or newly developed may be used. Moreover, it is applicable even if it is at least.

  The second feature of the dispersible colorant used in the present invention is that it is a dispersible colorant that can be dispersed alone in an aqueous medium in a state where the water-insoluble colorant 1 has the chargeable resin pseudo fine particles 2 fixed thereto. It is in. As described above, the dispersible colorant used in the present invention is essentially a self-dispersing agent that can be stably dispersed in water and water-based inks without the aid of other surfactants or polymer dispersants. It is a sex color material. This definition and determination method will be described in detail later. Therefore, the dispersible colorant used in the present invention is added with a polymer dispersant or other resin component or surfactant component that may be released for a long term for the purpose of stabilizing the dispersion of the colorant. There is no need. As a result, when the dispersible color material used in the present invention is used as a water-based ink, the degree of freedom of design regarding components other than the dispersible color material is increased. For example, the permeability of ink such as plain paper is increased. It is also possible to obtain a water-based ink that can obtain a sufficiently high printing density even on a high recording medium.

  The self-dispersibility of the dispersible colorant used in the present invention can be confirmed as follows, for example. The ink or water dispersion in which the color material is dispersed is diluted 10-fold with pure water, and concentrated to the original concentration using an ultrafiltration filter having a molecular weight cut off of 50,000. This concentrated solution is separated in a centrifuge at 12,000 rpm for 2 hours, and the sediment is taken out and redispersed in pure water. At this time, it is judged that what the sediment can redisperse well has self-dispersibility. Whether or not it is well re-dispersed depends on whether it is uniformly distributed visually, or if there is no noticeable sediment during standing for 1 to 2 hours, or if it is shaken lightly It can be comprehensively judged from the fact that the average particle size is less than twice the particle size before operation when the dispersed particle size is measured by the dynamic light scattering method.

  As described above, the dispersible colorant used in the present invention takes a form having a high specific surface area by fixing the chargeable resin pseudo fine particles, and has a large amount of charges on its vast surface. Realize excellent storage stability. Therefore, more preferable results can be obtained when the chargeable resin pseudo fine particles are scattered in large numbers and fixed to the color material. In particular, it is desirable that there is a certain distance between the adhering charged resin pseudo fine particles, and it is preferably distributed uniformly. More preferably, it is desirable that a part of the color material particle surface is exposed between the chargeable resin pseudo fine particles. Such a form can be confirmed by observing the aqueous ink according to the present invention with a transmission electron microscope or a scanning electron microscope. That is, a plurality of charged resin pseudo fine particles fixed to the color material surface are fixed at a certain distance, or the color material surface is exposed between the fixed charged resin pseudo fine particles. The state can be observed. In addition, the charged resin pseudo fine particles are sometimes close to each other and may be observed to be fused in some cases, but even in this case, there is a distance between the charged resin pseudo fine particles as a whole. If the surface of the color material is exposed and these states are distributed, it is considered that the charged resin pseudo fine particles are scattered and fixed to the color material. This will be apparent to those skilled in the art.

  Furthermore, it has been clarified that the water-based ink containing the dispersible colorant having the above-described characteristics used in the present invention exhibits excellent quick drying on the recording medium. The reason for this is not clear, but is thought to be based on the following mechanism. As described above, the dispersible color material is dispersed in the ink in a form in which charged resin pseudo fine particles are fixed to the color material surface. When this ink reaches the recording medium, the aqueous solvent in the ink (hereinafter referred to as “ink solvent”) is pores on the recording medium due to capillary action (in the case of plain paper, voids between cellulose fibers; In case of glossy paper, it is absorbed into the pores of the receiving layer) At this time, the dispersible color material used in the present invention has many fine gaps due to the morphological characteristics of the charged resin pseudo fine particles interspersed at portions where the color materials are in contact with each other. For this reason, a capillary phenomenon acts on the ink solvent existing between the color materials, and it is quickly absorbed into the recording medium. In the water-based ink according to the present invention, the dispersible colorant having a form in which charged resin pseudo fine particles are scattered on the surface exhibits a more preferable quick drying property. Expected to be achieved.

  The surface functional group density of the dispersible colorant according to the present invention is preferably 250 μmol / g or more and less than 1,000 μmol / g, and more preferably 290 μmol / g or more and less than 900 μmol / g. When the surface functional group density is smaller than this range, the long-term storage stability of the dispersible colorant may be deteriorated. In addition, when the surface functional group density is considerably larger than this range, the dispersion stability becomes too high, and it tends to penetrate on the recording medium, making it difficult to ensure a high printing density.

  The surface functional group density is determined as follows, for example. First, a large excess amount of hydrochloric acid (HCl) aqueous solution is added to an aqueous dispersion or ink containing a dispersible colorant to be measured, and the mixture is precipitated by a centrifuge at 20,000 rpm for 1 hour. The sediment is collected and redispersed in pure water, and then the solid content is measured by a drying method. The redispersed sediment is weighed, and a dispersion obtained by adding a known amount of sodium hydrogen carbonate and stirring the mixture is further sedimented in a centrifuge at 80,000 rpm for 2 hours. Weigh the supernatant and subtract the known amount of sodium bicarbonate from the neutralization amount obtained by neutralization titration with 0.1 N hydrochloric acid to obtain the surface functional group density as the number of moles per gram of colorant. It is done.

  Next, each component constituting the dispersible colorant used in the present invention will be described.

[Color material]
The color material which is a constituent component of the dispersible color material used in the present invention will be described below. As the color material used in the present invention, among color materials known or newly developed, it is desirable to use a color material that is insoluble in water and can be stably dispersed in water together with a dispersant. Examples of such materials include hydrophobic dyes, inorganic pigments, organic pigments, metal colloids, and colored resin particles. Preferably, a coloring material having a dispersed particle size in the range of 0.01 to 0.5 μm (10 to 500 nm), particularly preferably in the range of 0.03 to 0.3 μm (30 to 300 nm) is used. A dispersible color material using a color material dispersed in this range is a preferable dispersible color material that gives an image having high coloring power and high weather resistance when used as an aqueous ink. In addition, let this dispersion | distribution particle size be the cumulant average value of the particle size measured by the dynamic light scattering method.

  In the present invention, examples of the inorganic pigment that can be effectively used for the coloring material include carbon black, titanium oxide, zinc white, zinc oxide, tripone, iron oxide, cadmium red, molybdenum red, chrome vermilion, and molybdate orange. , Yellow lead, chrome yellow, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, pyridian, cobalt green, titanium cobalt green, cobalt chrome green, ultramarine blue, ultramarine blue, bitumen, cobalt blue, cerulean blue, manganese violet, Examples include cobalt violet and mica.

  Examples of organic pigments that can be effectively used in the present invention include azo, azomethine, polyazo, phthalocyanine, quinacridone, anthraquinone, indigo, thioindigo, quinophthalone, benzimidazolone, Various pigments such as indoline and isoindolinone are listed.

  Other organic insoluble colorants that can be used in the present invention include, for example, azo, anthraquinone, indigo, phthalocyanine, carbonyl, quinoneimine, methine, quinoline, nitro, etc. Dyes. Of these, disperse dyes are particularly preferable.

[Charged resin pseudo fine particles]
The charged resin pseudo fine particles, which are another component of the dispersible color material used in the present invention, are substantially insoluble in water, and the color material to be fixed in water (or in ink). The dispersion unit (dispersion particle size) is small, and is defined as a fine body formed by aggregating resin components having a sufficiently high degree of polymerization. The form of the minute body is pseudo close to a sphere, or a plurality of minute bodies (chargeable resin pseudo fine particles) are arranged within a certain range. It is preferable that the resin components constituting the chargeable resin pseudo fine particles are physically or chemically cross-linked with each other. Whether the resin components constituting the chargeable resin pseudo fine particles are cross-linked with each other can be confirmed by using, for example, the following method. The resin component constituting the chargeable resin pseudo fine particles is estimated in advance by a known analysis method, and a linear polymer having the same chemical structure (or the same monomer unit composition) is synthesized by solution polymerization, On the other hand, when the chargeable resin pseudo fine particles and the polymer are immersed in an organic solvent, which is a good solvent, and their solubility is compared, the chargeability is determined when the solubility of the chargeable resin pseudo fine particles is lower than the solubility of the polymer. It is confirmed that the interior of the resin pseudo fine particles is crosslinked.

  As another preferred embodiment, when the dispersed particle size of the charged resin pseudo fine particles in water can be measured by, for example, the dynamic light scattering method, the average value of the dispersed particle size of the cumulant is preferably used. It is desirable to be in the range of 10 nm to 200 nm. Furthermore, from the viewpoint of long-term storage stability of the dispersible colorant, it is more preferable that the polydispersity index of the dispersed particle diameter is suppressed to less than 0.2. When the center value of the dispersed particle diameter is larger than 200 nm or when the polydispersity index is larger than 0.2, the original purpose of finely dispersing and stabilizing the coloring material may not be sufficiently achieved. Further, when the average value of the dispersed particle diameter is smaller than 10 nm, the form as the chargeable resin pseudo fine particles cannot be sufficiently maintained, and the resin is easily dissolved in water, so that the merit of the present invention cannot be obtained. There is a case. On the other hand, in the range of 10 nm or more and 200 nm or less, the particle size is smaller than the color material particles themselves, whereby the dispersion stabilization of the color material by the fixing of the chargeable resin pseudo fine particles in the present invention is effectively expressed. . The above preferred embodiment is the same when the dispersed particle size of the chargeable resin pseudo fine particles is not measurable. In that case, for example, the average diameter of the chargeable resin pseudo fine particles in the electron microscope observation is as described above. It is considered to be a preferred range or a range equivalent thereto.

  When the color material is an organic pigment, in addition to the above range, as described above, the charged resin pseudo fine particles are smaller than the pigment dispersed particle size and larger than the color material molecule. It is particularly desirable because a dispersible colorant having a structurally extremely stable and high dispersibility can be obtained.

  The chargeability in the present invention refers to a state in which a functional group that is ionized in some form in the aqueous medium itself is retained, and is desirably self-dispersible by the chargeability. Therefore, whether or not it is a chargeable resin pseudo fine particle is determined by a method of measuring the surface zeta potential of the chargeable resin pseudo fine particle by a publicly known and arbitrary method, a potentiometric titration by a method as described later, and a functional group. A method for calculating the density, a method for confirming the dependency of dispersion stability on the electrolyte concentration by adding an electrolyte to the aqueous dispersion of the charged resin pseudo fine particles, or a chemical structure analysis of the charged resin pseudo fine particles as a known method The method can be confirmed by any one of the methods of examining the presence or absence of an ionic functional group.

  The resin component constituting the chargeable resin pseudo fine particles may be any resin component such as any commonly used natural or synthetic polymer, or a newly developed polymer for the present invention, without limitation. . Examples of resin components that can be used include acrylic resins, styrene / acrylic resins, polyester resins, polyurethane resins, polyurea resins, polysaccharides, and polypeptides. In particular, from the standpoint that it can be used generally and the functional design of the chargeable resin pseudo fine particles can be easily performed, a polymer or copolymer of a monomer component having a radical polymerizable unsaturated bond, such as an acrylic resin or a styrene / acrylic resin, is used. A polymer can be preferably used.

  Specifically, for example, anionic hydrophilic monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, fumaric acid, and salts thereof, Anionic hydrophilic monomers having a sulfonic acid group such as styrene sulfonic acid, sulfonic acid-2-propyl acrylamide, acrylic acid-2-ethyl sulfonate, methacrylic acid-2-ethyl sulfonate, butyl acrylamide sulfonic acid, etc. Examples thereof include anionic hydrophilic monomers having a phosphonic acid group such as a salt, ethyl methacrylate-2-phosphonate, and acrylic acid-2-ethyl phosphonate.

  The chargeable resin pseudo fine particles preferably used in the present invention preferably have a glass transition temperature (Tg) of the resin constituting the fine particles of −40 ° C. to 60 ° C. When the Tg of the resin component is within this range, high chargeability is imparted to the chargeable resin pseudo fine particles, and the adjacent color materials on the recording paper can be formed to form a strong colored film. Therefore, high scratch resistance can be imparted to a printed matter obtained using the dispersible color material having such a configuration.

  The glass transition temperature of the resin constituting the chargeable resin pseudo fine particles fixed to the color material can be measured by the following procedure. The dispersible colorant is subjected to acid precipitation with hydrochloric acid or the like to recover the precipitate. Furthermore, the charged resin pseudo fine particles fixed to the color material can be obtained by subjecting the precipitate to Soxhlet extraction using an organic solvent such as THF (tetrahydrofuran) and distilling off the organic solvent. And the glass transition temperature can be measured by carrying out the differential scanning thermal analysis of the obtained chargeable resin pseudo fine particle component. As a measuring method, for example, a device such as DSC822e manufactured by METTTLER may be used. In the case of an aqueous dispersion in which a dispersible colorant and a water-soluble nonionic resin coexist, they can be separated using a centrifuge. For example, when separation is performed under a centrifugal separation condition of 12,000 rpm, a dispersible color material can be obtained as a sediment.

  The dispersible colorant of the present invention can be selected by appropriately selecting the monomer species having a radical polymerizable unsaturated bond of the resin component constituting the chargeable resin pseudo fine particles and the copolymerization ratio while satisfying the above-described conditions, and A further function can be imparted to the chargeable resin pseudo fine particles fixed to the color material. Specific examples of the monomer species include hydrophobic monomers as described below, anionic hydrophilic monomers as described above, and nonionic hydrophilic monomers as described later.

  Examples of the hydrophobic monomer include methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid-n-propyl, acrylic acid-n-butyl, acrylic acid-t-butyl, benzyl acrylate, methyl methacrylate, methacrylic acid. (Meth) acrylic acid esters such as ethyl acetate, isopropyl methacrylate, methacrylate-n-propyl, methacrylate-n-butyl, isobutyl methacrylate, tert-butyl methacrylate, tridecyl methacrylate, benzyl methacrylate; styrene Styrene monomers such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-tert-butylstyrene; itaconate such as benzyl itaconate; dimethyl maleate, etc. Maleic acid Ether; fumaric acid such as fumaric acid esters such as dimethyl acrylonitrile, methacrylonitrile, vinyl acetate, and the like.

  Moreover, what was mentioned above is mentioned as a hydrophilic monomer which has an anionic group.

  Further, as the nonionic hydrophilic monomer, specifically, a hydroxyl group having a radical polymerizable unsaturated bond and strong hydrophilicity in a structure such as hydroxyethyl (meth) acrylate and hydroxylpropyl (meth) acrylate. Monomers having a group at the same time, and monomers having an alkylene oxide group such as methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, etc. Also, various known or novel oligomers, macromonomers and the like can be used without limitation.

  In particular, the alkylene oxide group-containing monomer is excellent in copolymerizability with the hydrophobic monomer component, from the viewpoint of uniformity of the surface properties of the chargeable resin pseudo fine particles, uniform adhesion to the colorant, and fusing properties. Gives favorable results.

  Depending on many control factors such as the type and copolymerization ratio of the monomer constituting the chargeable resin pseudo fine particles, the type and concentration of the polymerization initiator used in the preparation, various kinds of dispersible colorant and chargeable resin pseudo fine particles The characteristics can be appropriately controlled. In particular, it is desirable that the chargeable resin pseudo fine particles are composed of a copolymer of monomer components including at least one type of hydrophobic monomer and at least one type of hydrophilic monomer among the monomers listed above. It is a mode. At this time, by using at least one kind of hydrophobic monomer, it is possible to achieve good form control by using at least one kind of hydrophilic monomer, and to achieve good adhesion to the colorant and thermal stability. Dispersion stability can be imparted to each. Therefore, by using these monomers simultaneously, it is possible to obtain chargeable resin pseudo fine particles that are always well fixed to the colorant and can impart good dispersion stability.

[Synthesis of chargeable resin pseudo fine particles and fixation to coloring material]
The method for synthesizing the chargeable resin pseudo fine particles and the method for fixing to the color material are carried out by a method for synthesizing the charge resin pseudo fine particles and a method for combining the charge resin pseudo fine particles and the color material. Can do. On the other hand, the present inventors, as a result of intensive studies, are dispersible colorants having the colorant and the chargeable resin pseudo fine particles smaller than the colorant, which are the characteristics of the present invention. It came to invent the manufacturing method which can obtain easily the dispersible color material of the state which this chargeable resin pseudo fine particles adhere to the material. Hereinafter, a suitable method for producing a dispersible color material, from which the dispersible color material used in the present invention can be easily obtained, will be described.

  As a result of the study by the present inventors, it has been clarified that the dispersible colorant used in the present invention having the above-described characteristics can be produced very simply by applying the aqueous precipitation polymerization method under the following conditions. It was. In such a production method, first, a water-insoluble colorant is dispersed with a dispersant to prepare a dispersed aqueous solution of the water-insoluble colorant. Next, in this dispersed aqueous solution, the chargeable resin pseudo fine particles are fixed to the coloring material by a step of aqueous precipitation polymerization of the radical polymerizable monomer using an aqueous radical polymerization initiator. The dispersible colorant obtained through this aqueous precipitation polymerization process is a water-insoluble color in which the chargeable resin pseudo fine particles synthesized in the aqueous precipitation polymerization process are strongly and firmly adhered to the colorant. It becomes a material and has excellent dispersion stability by itself. Further, in the above aqueous precipitation polymerization process, the characteristics of the chargeable resin pseudo fine particles can be easily controlled to the preferred form as described above. And the charge resin pseudo fine particles are satisfactorily achieved. Hereinafter, preferred embodiments of the manufacturing method will be described in more detail.

(Dispersion of water-insoluble colorant)
First, the water-insoluble colorant preferably used in the present invention as described above is dispersed with a dispersant to obtain an aqueous dispersion. As the dispersant for dispersing the coloring material in the aqueous solution, any of ionic, nonionic, etc. can be used, but from the viewpoint of maintaining dispersion stability in the subsequent polymerization step, the polymer dispersant or water-soluble It is desirable to use a polymer. In particular, a radically polymerizable monomer that is sufficiently water-soluble and that serves as an adsorption site to the oil droplet interface of the radically polymerizable monomer surface and the hydrophobic monomer added in the polymerization process is preferably used. It is done. More preferably, at least one of the hydrophobic monomers used in the subsequent polymerization step is present as a unit constituting the dispersing agent, so that the color of the charged resin pseudo fine particles in the subsequent polymerization step. This is preferable from the viewpoint of easily inducing adhesion to the material.

  The production method of the polymer dispersant and the water-soluble polymer that functions as a dispersant that can be used in the present invention is not particularly limited. For example, a monomer having an ionic group and another polymerizable monomer are non-polymerized. It can manufacture by making it react in the presence or absence of a catalyst in a reactive solvent. In particular, a styrene / acrylic polymer compound obtained by polymerizing a monomer having an ionic group as described above and a styrene monomer as essential components, or a monomer having an ionic group, and the number of carbon atoms is 5. From the ionic group-containing acrylic polymer compound obtained by polymerizing the above (meth) acrylic acid ester monomer as an essential component, it has been clarified that good results can be obtained by using a dispersant selected. . At this time, when the obtained dispersible colorant is intended to have an anionic group in particular, an anionic dispersant, while the obtained dispersible colorant is intended to have a cationic group in particular. In this case, it is desirable to select a dispersant having a cationic group or a nonionic dispersant.

  From the viewpoint of coexistence of promoting the fixation of the chargeable resin pseudo fine particles to the coloring material in the subsequent aqueous precipitation polymerization process and maintaining the dispersion stability of the coloring material in the polymerization process. It is also desirable to use those having an acid value of 100 or more and 250 or less in the case of using an acid, and those having an amine value of 150 or more and 300 or less in the case of using a cationic dispersant. When the acid value and the amine value are smaller than these ranges, the affinity between the hydrophobic monomer and the dispersant becomes higher than the affinity between the colorant and the dispersant during the aqueous precipitation polymerization, and the chargeable resin pseudo In some cases, the dispersing agent may be detached from the surface of the color material before the fine particles are fixed to the color material, and the dispersed state cannot be maintained. In addition, if the acid value and amine value are larger than these ranges, the excluded volume effect of the dispersant on the surface of the color material and the electrostatic repulsion force become too strong, so that the chargeable resin pseudo fine particles adhere to the color material. May be inhibited. When using an anionic dispersant, it is preferable to select a dispersant having a carboxyl group as an anionic group from the viewpoint of not inhibiting the adhesion of the resin fine particles to the colorant.

  In the process of making a water-insoluble colorant into a dispersion aqueous solution with a dispersant, the colorant preferably has a dispersed particle diameter in the range of 0.01 μm to 0.5 μm (10 nm to 500 nm), particularly preferably 0.03 μm or more. Disperse in a range of 0.3 μm or less (30 nm or more and 300 nm or less). The dispersed particle diameter in this process largely reflects the dispersed particle diameter of the dispersible colorant to be obtained, and the above range is preferable from the viewpoint of the above-mentioned coloring power, image weather resistance, and dispersion stability.

  The dispersion particle size distribution of the water-insoluble colorant used in the present invention is preferably monodispersed as much as possible. In general, the particle size distribution of the dispersible colorant obtained by fixing the charged resin pseudo fine particles becomes narrower than the particle size distribution of the dispersed aqueous solution before the polymerization step shown in FIG. Although it tends to be, it basically depends on the particle size distribution of the dispersed aqueous solution. It is also important to narrow the particle size distribution of the color material in order to surely induce fixation due to heteroaggregation of the color material and the charged resin pseudo fine particles. According to the study by the present inventors, when the polydispersity index of the color material is in the range of 0.25 or less, the dispersion stability of the obtained dispersible color material becomes excellent.

  Here, the particle size of the colorant in a dispersed state varies depending on various measurement methods. Particularly, the organic pigment is very small when it is a spherical particle, but in the present invention, the colorant is moved by ELS-8000 manufactured by Otsuka Electronics Co., Ltd. The average particle size and the polydispersity index obtained by the measurement based on the dynamic light scattering method and cumulant analysis were used.

  The method for dispersing the water-insoluble coloring material in water may be any method that uses a dispersing agent as described above, among the methods in which the coloring material can be stably dispersed in water under the conditions described above. It is not limited to any method that is used. Alternatively, a dispersion method newly developed for the present invention may be used. In general, for example, when the water-insoluble colorant is a pigment, the addition amount of the polymer dispersant to be used is suitably 10% by mass or more and 130% by mass or less based on the pigment.

  Examples of the dispersion method of the color material used in the present invention include, for example, a dispersion machine such as a paint shaker, a sand mill, an agitator mill, and a three roll mill, a high-pressure homogenizer such as a microfluidizer, a nanomizer, and an optimizer, an ultrasonic dispersion machine, and the like. Any dispersion method that is generally used for each color material is not limited.

(Aqueous precipitation polymerization)
Subsequently, a preferred embodiment of the aqueous precipitation polymerization, which is a step of synthesizing the chargeable resin pseudo fine particles, which is a feature of the present invention, and fixing it to the coloring material will be described. In addition, this invention is not restrict | limited at all by embodiment described below. FIG. 2 is a process diagram schematically showing a process flow of the manufacturing method. The process up to obtaining a dispersible colorant by this step is considered as follows. First, as shown in FIG. 2A, a dispersed aqueous solution in which the coloring material 1 is dispersed in the aqueous solution by the dispersant 3 is prepared. At this time, the coloring material is dispersed and stabilized by adsorption of the dispersing agent, and this adsorption is in a thermal equilibrium state. Next, the temperature of the dispersion aqueous solution prepared in FIG. 2A is raised while stirring, and the monomer component 4 is added thereto together with, for example, the aqueous radical polymerization initiator 5 (see FIG. 2B). The added aqueous radical polymerization initiator cleaves when heated to generate radicals, and among the monomer components added to the aqueous dispersion, a small amount of the hydrophobic monomer dissolved in the aqueous phase and the aqueous phase Contributes to the reaction with the water-soluble monomer.

  FIG. 3 is a schematic diagram illustrating a process until the monomer 4 is polymerized to produce a dispersible colorant. When the reaction of the monomer 4 as described above proceeds, the oligomer 7 generated by the polymerization reaction of the monomer component becomes insoluble in water and precipitates from the aqueous phase to become a precipitate 8. However, since the oligomer 7 deposited at this time does not have sufficient dispersion stability, the charged resin pseudo fine particles 2 are formed together. Further, the charged resin pseudo fine particles 2 cause hetero-aggregation with the hydrophobic surface of the color material in the aqueous dispersion as a nucleus, and the resin component constituting the surface of the color material 1 and the charge resin pseudo fine particles 2 has a hydrophobic interaction. Strongly adsorbed by. At this time, the polymerization reaction continues to proceed inside the chargeable resin pseudo fine particles 2, and changes to a more energetically stable form while increasing the adsorption point with the colorant 1. At the same time, since the inside of the chargeable resin pseudo fine particles 2 is highly physically crosslinked, the form that adsorbs the color material 1 most stably is fixed and is in a fixed state. On the other hand, the coloring material 1 is stabilized by fixing the plurality of chargeable resin pseudo fine particles 2, and the dispersant 3 in an equilibrium state is detached from the surface of the coloring material 1.

  FIG. 4 shows a schematic diagram of the chargeable resin pseudo fine particles 2 obtained as described above on the fixing interface side with the coloring material 1. As shown in FIG. 4, since the charged resin pseudo fine particles, which are aggregates of resin components, are present in an arbitrarily distributed hydrophilic monomer unit 9-1, hydrophobic monomer unit 9-2, etc. The surface energy has a distribution, and there are many adsorption points 10 that coincide with the surface energy of the color material.

  FIG. 5 shows an enlarged schematic view of the fixing interface portion between a part of the chargeable resin pseudo fine particles 11 and the part 1a of the color material particles. The interface 11 of the chargeable resin pseudo fine particles is shown in FIG. While adsorbing the adsorbing point 10, it takes a form corresponding to the surface shape of the part 1a of the color material and adheres stably. As described above, since the polymerization reaction is proceeding in the chargeable resin pseudo fine particles also in this process, fixation to the coloring material is achieved by fixing the adsorption in a stabilized form. Through the above-described process, the dispersible color material having the above-described configuration is easily formed (see FIG. 2D). At this time, in a system in which the chargeable resin pseudo fine particles have sufficient surface charge to achieve self-dispersibility, the charge resin pseudo fine particles are interspersed in the process of adsorption and fixation to the coloring material by heteroaggregation. When the electrostatic repulsive force acts mutually, the chargeable resin pseudo fine particles are scattered and fixed to the color material, and the preferred form described above is obtained.

  The polymerization reaction conditions vary depending on the properties of the polymerization initiator, the dispersant, and the monomer to be used. For example, the reaction temperature is 100 ° C. or lower, preferably 40 ° C. or higher and 80 ° C. or lower. The reaction time is 1 hour or more, preferably 6 hours or more and 30 hours or less. The stirring speed during the reaction is 50 rpm to 500 rpm, preferably 150 rpm to 400 rpm.

  In the above-described steps, particularly when the chargeable resin pseudo fine particles are obtained by polymerizing a monomer component containing at least one kind of hydrophobic monomer and at least one kind of hydrophilic monomer, the monomer component is preferably an aqueous solution. It is desirable to drop it into a dispersed aqueous solution of a water-insoluble colorant that contains a radical polymerization initiator in advance. Alternatively, it is also desirable to add the water-insoluble colorant dropwise at the same time or separately from the aqueous radical polymerization initiator in the aqueous dispersion. In order to uniformly obtain desired charged resin pseudo fine particles from a mixture of monomers having different properties such as a hydrophobic monomer and a hydrophilic monomer, it is desirable to always keep the copolymerization ratio of the monomers having different properties constant. . When the mixture of monomers is added to the polymerization system in excess of the amount of monomer consumed in the polymerization reaction within a certain time, only a specific monomer species is polymerized in advance, and the remaining monomers are polymerized in advance. There is a tendency to polymerize after the consumed monomer is consumed, and in this case, a large non-uniformity occurs in the properties of the generated chargeable resin pseudo fine particles. Among the charged resin pseudo fine particles generated in this way, those having a particularly large hydrophilic monomer component content may not be able to adhere to the surface of the color material.

  Furthermore, when the resin component has a high content of the hydrophilic monomer component, it may not be precipitated due to its high hydrophilicity, and may remain in the system as a water-soluble resin component without forming charged resin pseudo fine particles. is there. On the other hand, by dropping the monomer component into a water-insoluble colorant-dispersed aqueous solution containing an aqueous radical polymerization initiator, the copolymerization ratio between the hydrophobic monomer and the hydrophilic monomer is always kept constant. Chargeable resin pseudo fine particles composed of a copolymerization ratio can be obtained uniformly.

  In addition, especially when anionic monomers such as acrylic acid and methacrylic acid are added to the polymerization system as hydrophilic monomers, they may become partially unstable depending on the characteristics of the polymer dispersant in which the colorant is dispersed. , May cause aggregation. In order to prevent this, it is also a preferred embodiment that the anionic monomer is neutralized in advance and added in the form of sodium salt or potassium salt.

  When preparing a water-based ink using the water-insoluble color material obtained by the above-described process, in which the chargeable resin pseudo fine particles according to the present invention are fixed to the color material, in addition to the above-described process, further purification treatment is performed. It is desirable to do. In particular, in the above, it is possible to carry out purification treatment on unreacted polymerization initiator, monomer component, dispersant, water-soluble resin component that has not been fixed, and chargeable resin pseudo fine particles, etc. Is important in maintaining high. As a purification method to be used, an optimum one may be selected from generally used purification methods. For example, purification using a centrifugal separation method or an ultrafiltration method is a preferred embodiment.

  Through the above-described steps, a dispersible color material in which charged resin pseudo fine particles made of a desired copolymer are fixed to the surface of the color material can be obtained by controlling many control factors. In particular, when an anionic monomer is used for the purpose of high dispersion stability, the dispersible colorant having undergone the process of the present invention has a large surface even if the amount of the anionic monomer used in the above process is relatively small. A functional group density can be obtained and high dispersion stability can be imparted. As a result, it becomes possible to increase the dispersion stability of the chargeable resin pseudo fine particles without impairing the long-term storage stability.

  Although this reason is not clear, the present inventors consider as follows. Polymerization is initiated by radicals generated in water, and when oligomers are precipitated to form charged resin pseudo fine particles, the portion having a large amount of anionic monomer-derived components is preferentially on the water phase side, that is, charged resin pseudo fine particles. Oriented near the surface. This state is maintained even after the chargeable resin pseudo fine particles are fixed to the color material. In the dispersible color material used in the present invention having a structurally large specific surface area, an anionic property derived from an anionic monomer component is further provided. Many groups are present, and as a result, the dispersible colorant obtained by the above-described production method is expected to be stabilized with fewer anionic monomer components.

[Water-soluble nonionic resin]
The water-soluble nonionic resin added to the ink, which is another feature of the ink according to the present invention, will be described. The water-soluble nonionic resin used in the present invention is preferably a copolymer of the nonionic hydrophobic monomer as mentioned above and a nonionic hydrophilic monomer. That is, by using a nonionic hydrophobic monomer as a constituent component of the resin, high fixability of the dispersible colorant on the recording paper can be obtained, while using a nonionic hydrophilic monomer as a constituent component of the resin. Then, the property of the resin is made water-soluble, and the water-soluble nonionic resin 15-1 is satisfactorily penetrated between the color material and the color material on the recording paper (FIG. 7a), and the gap between the color materials is filled. The water-soluble nonionic resin that has permeated between the colorant and the color material forms a resin film 15-2 (FIG. 7b), and makes it possible to impart smoothness to the recorded image. That is, the water-soluble nonionic resin having such a structure contained in the ink fills the gap between the color materials on the recording paper, forms a film, and smoothes the recorded image surface, thereby improving the glossiness of the image. Improvements can be made.

Examples of the water-soluble nonionic resin that can be suitably used in the present invention include polymers of monomers containing an alkylene oxide group, or monomers or vinyl alcohol containing an alkylene oxide group and styrene or methyl methacrylate. A polymer etc. are mentioned. In particular, the following copolymers are suitable. Examples include 40-70 / 60-30 copolymers of styrene / CH ₂ ═C (R ₁ ) COOR ₂ . However R ₁ and R ₂ in the formula represents the followings. Is R ₁ = H or CH _3, R ₂ = - a _{(CH 2 CH 2 O) n} -R 3 (n = 1~30), R 3 in the formula is, R ₃ = H or CH ₃ It is.

  On the other hand, when the ink contains a water-soluble chargeable resin copolymerized with an anionic or cationic monomer instead of the nonionic hydrophilic monomer, it is not preferable from the following points. When the chargeable resin pseudo fine particles of the dispersible colorant and the water-soluble chargeable resin are electrically contradictory, that is, when the chargeable fine particles are anionic and the water-soluble chargeable resin is cationic, When the chargeable fine particles are cationic and the water-soluble chargeable resin is anionic, the ions of the dispersible colorant and the ions of the water-soluble chargeable resin may be ion-bonded and aggregated to lose dispersibility. is there. On the other hand, when the chargeable resin pseudo fine particles of the dispersible color material and the water-soluble charge resin are electrically homogeneous, the water-soluble charge resin remains in the gap between the dispersible color material and the dispersible color material. However, it is more preferable to use a nonionic hydrophilic monomer because the effect of improving the glossiness of the recorded image may be reduced.

  The water-soluble nonionic resin used in the present invention preferably has a weight average molecular weight Mw of 1,000 to 100,000, particularly preferably 2,000 to 30,000. Furthermore, it is preferable that it is 2,000-10,000. If it is this range, the fluidity | liquidity for giving smoothness to a recorded image can be obtained. Further, as the content of the water-soluble nonionic resin, the recording image can be smoothened by adding 1% by mass or more to the ink. Further, although there is no particular limitation, since the viscosity of the ink becomes high and the fluidity for imparting smoothness to the recorded image may be lost, the content in the ink may be 10% by mass or less. preferable.

[Emulsion particles]
The emulsion particles, which are another feature of the present invention, may be synthesized by a known method or synthesized by removing the coloring material by the above method, but there are no problems. Are preferably homogeneous or nonionic. That is, if the charged fine particles are anionic, the emulsion particles must be anionic, and if the charged fine particles are cationic, the emulsion particles must be cationic. If electrically contradictory, ions of the dispersible colorant and ions of the emulsion particles may be ion-bonded and aggregated to lose dispersibility. Therefore, it is necessary that the emulsion particles are electrically homogeneous or nonionic with the chargeable fine particles of the dispersible colorant.

  The emulsion particles preferably have an average particle diameter of 10 nm to 80 nm in the aqueous ink. If the average particle size is larger than 10 nm, the ink stays on the recording medium without penetrating the recording medium, and can fill the gap between the dispersible colorant and the dispersible colorant to give the image smoothness and gloss. Improvement is obtained. On the other hand, when the average particle size of the emulsion particles exceeds 80 nm, the gap between the dispersible colorant and the dispersible colorant is more than the effect of filling the dispersible colorant, creating a further gap and losing smoothness. Sometimes.

  Furthermore, it is desirable that the glass transition temperature (Tg) of the emulsion particles is −40 ° C. or higher and 60 ° C. or lower. By being in this range, a film is formed in the gap between the dispersible colorant and the dispersible colorant, and smoothness and film strength are given to the recorded image surface, and either glossiness or scratch resistance of the recorded image is provided. An improvement can be obtained. At this time, depending on the difference in the glass transition temperature (Tg) of the emulsion particles, the following three alternative effects can be mentioned. However, a composite system having these effects can also be selected by adding emulsion particles having different Tg.

  First, the emulsion particles 16-1 dispersed in the form of particles in the water-based ink are stacked while maintaining the state of the particles at the time of recording image formation, and a film is formed by filling the gap between the dispersible color material and the dispersible color material. First effect (FIG. 8a). Next, the emulsion particles dispersed in the form of particles in the water-based ink are crushed at the time of recording image formation, and the gap between the emulsion particles 16-2 and the emulsion particles stacked while maintaining the state of the particles is filled to form a film. Second effect (FIG. 8b). Then, the emulsion particles dispersed in the form of particles in the water-based ink lose the state of the particles at the time of recording image formation to obtain fluidity, flow into the remaining gap (16-3), fill the gap and form a film. (16-4) Third effects can be obtained respectively (FIGS. 8c and d). These first to third effects can also give smoothness to the recorded image surface by selecting the Tg of the resin component constituting the emulsion particles. In addition, when combining each effect, it is necessary to select the Tg range in the same way, or to mix the emulsion particles with different Tg as described above to synergistically give the recorded image surface. You can also. The gloss of the recorded image can be improved by the action of the emulsion particles as described above.

  Such emulsion particles are commercially available as a luster (matting agent) used to improve glossiness of aqueous adhesive compositions or printed materials. For example, Japanese Patent Nos. 3350518 and 3339629 describe a water-based emulsion composed of a urethane resin. These water-based emulsions are prepared by synthesizing a urethane resin in a solvent exhibiting a predetermined amount of solubility in water (most preferably, methyl ethyl ketone, etc.), neutralizing in water and then distilling off the organic solvent with stirring. be able to. Japanese Patent Application Laid-Open No. 10-279879 discloses a method of obtaining an aqueous emulsion by supplying two or more kinds of monomer components to an aqueous system all at once or continuously.

  In the case of these aqueous emulsions, a monomer having an ionic functional group such as a hydroxyl group or a sulfone group needs to be contained in the resin in order to stably disperse in the aqueous system. Therefore, in general emulsion polymerization or suspension polymerization, these ionic functional group-containing monomers may not be sufficiently contained in the emulsion particles. In order to avoid this problem, a polymer having an ionic functional group is polymerized in advance and then the polymerization solvent is distilled off, or a monomer having an ionic functional group and a hydrophobic monomer are subjected to aqueous precipitation polymerization in an aqueous phase system, A technique for producing an aqueous emulsion is employed. The emulsion suitable for the present invention may be prepared by any of the two methods described above, and the polymer constituting the emulsion may be any resin.

  As the content of the emulsion particles, smoothness can be imparted to the recorded image by adding 0.1% by mass or more to the ink. Moreover, although there is no restriction | limiting in particular, It is more preferable to set it as content of 10 mass% or less in an ink. This is because the viscosity of the ink is increased and the fluidity for imparting smoothness to the recorded image may be lost.

[Water-based ink]
The water-based ink according to the present invention includes the dispersible color material described above and at least one of a water-soluble nonionic resin and emulsion particles. When the coloring material to be used is a pigment, the pigment content is generally 0.1% by mass or more and 20% by mass or less, preferably 0.3% by mass or more and 15% by mass or less with respect to the ink. Further, as the aqueous medium, water or a mixed medium containing a water-soluble organic solvent as necessary is also preferable. Further, it may contain a penetrant, an antiseptic, an antifungal agent and the like for helping the permeability to the recording medium.

  As shown in FIG. 1, the dispersible color material used in the present invention is present in the ink in a state where the chargeable resin pseudo fine particles 2 are fixed to the surface of the color material 1. Therefore, the color material adheres to the recording medium and the adjacent color material on the recording paper via the chargeable resin pseudo fine particles fixed to the surface. Accordingly, the printed matter obtained using the water-based ink of the present invention has excellent scratch resistance.

  Further, in the case of using a pigment as the coloring material, the ratio of the pigment and the chargeable resin pseudo fine particles (resin mass / pigment mass = B / P) is in the range of 0.3 or more and 4.0 or less. It can be said that this is a desirable embodiment of the present invention in order to improve the scratch resistance of the printed matter formed of the color material. By setting the B / P ratio to be 0.3 or more, it is possible to impart excellent scratch resistance to the printed matter by improving the adhesion between the color materials and between the color material and the recording medium. In particular, in the case of aqueous ink using a dispersible color material formed by fixing charged resin pseudo fine particles comprising a copolymer component having a glass transition temperature of −40 ° C. or more and 60 ° C. or less, the film formation Can be exhibited more effectively, and the result is that the scratch resistance of glossy paper is further improved. When B / P is significantly larger than 4.0, the ink becomes highly viscous as a whole. In particular, when used in an ink jet recording apparatus, ejection stability may be impaired. In addition, since the amount of resin is extremely large relative to the color material, the color density of the color material on the recording medium is hindered, and the print density may not be sufficiently obtained. By controlling the B / P value within the range of 0.3 to 4.0, the water-based ink having excellent scratch resistance and compatible with ejection stability in the ink jet recording apparatus can be obtained. it can.

  The resin mass as used herein refers to the total amount of the chargeable resin pseudo fine particles contained in the ink according to the present invention, and may include other resin components that are clearly strongly adsorbed on the pigment surface. . However, the water-soluble resin component that can be easily separated from the pigment is not included.

  The above-mentioned B / P value can be generally obtained by differential thermogravimetric analysis, but in the present invention, it is a value measured and calculated with TGA / SDTA851 manufactured by METTTLER. That is, in the present invention, in the case of the water-based inkjet recording ink containing the water-soluble nonionic resin and the dispersible colorant according to the present invention, the ink was centrifuged at 80,000 rotations for 2 hours. The precipitate was dried and weighed, and the mass change before and after the decomposition temperature of each of the pigment and the resin component when the temperature was raised in a nitrogen atmosphere or in the air was calculated, and B / P was calculated. On the other hand, in the case of an aqueous inkjet recording ink containing an emulsion and a dispersible colorant, the precipitate obtained by centrifuging the ink at 25,000 rpm for 3 hours is dried, weighed, and a nitrogen atmosphere or The mass change before and after the decomposition temperature of the pigment and the resin component when the temperature was raised in the atmosphere was determined, and B / P was calculated.

[Recorded image]
The ink according to the present invention can be suitably used for recording using an ink jet recording apparatus as described later. The recording medium used at this time can be used without limitation even if it is a medium capable of ink jet recording.

[Image recording method and recording apparatus]
The dispersible color material used in the present invention and the water-based ink containing the color material are used for an inkjet discharge type head, and also as an ink tank in which the ink is stored or for filling the ink tank. It is also effective as an ink. In particular, the present invention provides an excellent effect in a bubble jet type recording head and recording apparatus among ink jet recording types.

  As for the typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. . This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the ink. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding the nucleate boiling to the electrothermal transducer, heat energy is generated in the electrothermal transducer, and the thermal action of the recording head This is effective because the film can be boiled on the surface and, as a result, the drive signals can be made to correspond one-to-one and bubbles in the ink can be formed. By the growth and contraction of the bubbles, ink is ejected through the ejection openings to form at least one droplet. It is more preferable that the drive signal has a pulse shape, because the bubble growth and contraction is performed immediately and appropriately, and thus ink discharge with particularly excellent responsiveness can be achieved. As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by adopting the conditions described in US Pat. No. 4,313,124, which is an invention relating to the rate of temperature increase of the heat acting surface.

  As the configuration of the recording head, in addition to the combination configuration (linear liquid channel or right-angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the heat acting part The present invention is also effective for configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations in which the lens is disposed in a bending region. In addition, the present invention is also effective for a configuration (Japanese Patent Laid-Open No. 59-123670, etc.) in which a discharge hole is used as a discharge portion of the electrothermal transducer when common to a plurality of electrothermal transducers. . Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is set by combining a plurality of recording heads as disclosed in the above specification. Either a satisfying configuration or a single recording head configuration may be used, but the present invention can exhibit the above-described effects more effectively.

  In addition, it is mounted on the main body of the device so that it can be electrically connected to the main body of the device and supplied with ink from the main body of the device. The present invention is also effective when a cartridge type recording head is used. In the present invention, it is preferable to add a recovery means for the recording head, a preliminary auxiliary means, etc. provided as a configuration of the recording apparatus to be applied, because the effects of the present invention can be further stabilized. is there. Specifically, a capping unit for the recording head, a cleaning unit, a pressurizing or suction unit, an electrothermal transducer, a heating element different from this, or a preheating unit using a combination of these, recording and the like Is a preliminary discharge mode for performing another discharge.

  Next, an Example and a comparative example are given and this invention is demonstrated concretely. The present invention is not limited by the following examples unless it exceeds the gist. In the text, “part” or “%” is based on mass unless otherwise specified.

[Example 1-1]
A recording ink 1-1 according to Example 1-1 was produced in the following manner. First, a mixed liquid composed of 10 parts of carbon black, 6 parts of glycerin, 10 parts of a styrene-acrylic acid resin dispersant, and 74 parts of water was subjected to a sand mill manufactured by Kanada Rika Kogyo Co., Ltd. at 1,500 rpm for 5 hours. Dispersion was performed to obtain Pigment Dispersion Liquid 1. In the sand mill, zirconia beads having a diameter of 0.6 mm were used, and the filling rate in the pot was 70%. The carbon black used in the present example is Black Pearls 880 (hereinafter abbreviated as BP880) marketed by Cabot Corporation in the United States. The styrene-acrylic acid resin dispersant has a copolymerization ratio of 70:30, Mw. = 8,000, acid value 170 was used. As this styrene-acrylic acid resin dispersant, water and potassium hydroxide equivalent to the above acid value were added in advance and stirred at 80 ° C. to obtain an aqueous solution. The obtained pigment dispersion 1-1 was stably dispersed with an average dispersion particle size of 98 nm, and the polydispersity index was 0.16.

  Next, 100 parts of the pigment dispersion 1-1 obtained above was heated to 70 ° C. under a nitrogen atmosphere, and the following three liquids were charged into the dropping device respectively while stirring with a motor for 6 hours. The polymerization was carried out dropwise. The solution was (1) 5.5 parts methyl methacrylate, (2) 0.5 parts acrylic acid, 0.25 parts potassium hydroxide and 20 parts water, (3) 0.05 parts potassium persulfate and 20 parts water. Consists of parts.

  The obtained dispersion was diluted 10-fold with water and centrifuged at 5,000 rpm for 10 minutes to remove the aggregating component. Then, it further refine | purified by centrifuging on conditions of 12,500 rpm and 2 hours, and the dispersible color material 1-1 which is a sediment was obtained.

  The dispersible colorant 1-1 is dispersed in water, centrifuged at 12,000 rpm for 60 minutes, and the precipitate is redispersed in water, dried, and scanned by an electron microscope JSM-6700 (Japan) When observed at 50,000 times by Electronic Hitech Co., Ltd., it was observed that charged resin pseudo fine particles smaller than the color material carbon black were fixed on the surface of the carbon black. In addition, about the color material after this described in a present Example, the form of the dispersible color material was confirmed with the method similar to the above.

  The dispersible colorant 1-1 obtained above was included in the ink at a concentration of 4%, and the following component composition was mixed with this, and further, a membrane filter having a pore size of 2.5 microns was used. Under pressure, the recording ink 1-1 of this example was prepared. The total amount of ink was adjusted with water so as to be 100 parts.

・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemical Co., Ltd.) 0.25 parts ・ Styrene / CH ₂ = C (R ₁ ) COOR ₂ 40/60 co-weight Combined (manufactured by Seiko Polymer Co., Ltd., weight average molecular weight Mw = 6,898)
4 parts [In the above formula, R ₁ = CH ₃ , R ₂ =-(CH ₂ CH ₂ O) ₂₃ -R ₃ , R ₃ = CH ₃ ]
・ Ion exchange water balance

[Example 1-2]
Using 100 parts of the pigment dispersion 1-1 obtained in Example 1-1 and heating to 70 ° C. in a nitrogen atmosphere, the following three liquids were charged into the dropping device while stirring with a motor for 6 hours. Was added dropwise to perform polymerization. The liquid was (1) 4.5 parts benzyl methacrylate, 1.2 parts butyl acrylate, (2) 0.3 parts acrylic acid, 0.15 parts potassium hydroxide and 20 parts water, (3) persulfuric acid. It consists of 0.05 part of potassium and 20 parts of water.

  By diluting the obtained dispersion 10 times with water and centrifuging at 5,000 rpm for 10 minutes to remove the agglomerated components, and further centrifuging at 12,500 rpm for 2 hours. It refine | purified and the dispersible color material 1-2 which is a sediment was obtained.

  The dispersible colorant 1-2 obtained above was included in the ink at a concentration of 4%, and the following component composition was mixed with this, and further, with a membrane filter having a pore size of 2.5 microns. The ink was subjected to pressure filtration to prepare a recording ink 1-2 of this example. The total amount of ink was adjusted with water so as to be 100 parts.

・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemicals Co., Ltd.) 0.25 part ・ Styrene / CH ₂ = C (R ₁ ) COOR ₂ 60/40 co-weight Combined (manufactured by Seiko Polymer Co., Ltd., weight average molecular weight Mw = 7,213)
1 part [in the above formula, R ₁ = CH ₃ , R ₂ =-(CH ₂ CH ₂ O) ₂₃ -R ₃ , R ₃ = CH ₃ ]
・ Ion exchange water balance

[Example 1-3]
A recording ink 1-3 according to this example was produced in the following manner. First, Pigment Red (PR) 122 (Ciba Specialty MAZENTA DMQ manufactured by Ciba Specialty Chemicals Co., Ltd.) as a coloring material has a composition comprising 10 parts, 6 parts glycerin, 10 parts styrene-acrylic acid dispersant, and 74 parts water. The liquid was dispersed in a sand mill manufactured by Kanada Rika Kogyo Co., Ltd. at 1,500 rpm for 5 hours to obtain pigment dispersion 5. In the sand mill, zirconia beads having a diameter of 0.6 mm were used, and the filling rate in the pot was 70%. The styrene-acrylic resin used as the dispersant was a copolymer having a copolymerization ratio of 70:30, Mw = 8,000, and an acid value of 170. The obtained pigment dispersion 1-3 was stably dispersed with an average dispersion particle size of 88 nm, and the polydispersity index was 0.13.

  Next, using 100 parts of the above pigment dispersion 1-3, while heating to 70 ° C. in a nitrogen atmosphere, the following three liquids were charged into a dropping device while being stirred with a motor, and dropped in 6 hours. In addition, polymerization was performed. (1) styrene 5.7 parts, (2) acrylic acid 0.3 parts, potassium hydroxide 0.15 parts and water 20 parts (3) VA057 (trade name, manufactured by Wako Pure Chemical Industries, Ltd., 2,2'-azobis (N- (2-carboxyethyl) amidinopropane)) is composed of 0.05 part and water 20 parts.

  By diluting the obtained dispersion 10 times with water and centrifuging at 5,000 rpm for 10 minutes to remove the agglomerated components, and further centrifuging at 12,500 rpm for 2 hours. Thus, dispersible colorant 1-3 as a sediment was obtained.

  The dispersible colorant 1-3 obtained above was included in the ink at a concentration of 4%, and the following component composition was mixed with this, and further, with a membrane filter having a pore size of 2.5 microns. Under pressure, the recording ink 1-3 of this example was prepared. The total amount of ink was adjusted with water so as to be 100 parts.

・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemical Co., Ltd.) 0.25 part ・ Styrene / vinyl alcohol 60/40 copolymer (manufactured by Seiko Polymer Co., Ltd., weight) Average molecular weight Mw = 4,030)
3.0 parts, remaining ion-exchanged water

[Example 1-4]
Recording ink 1-4 according to the present example was produced in the following manner. First, a mixed liquid having a composition comprising 10 parts of FAST YELLOW 7413 (Pigment Yellow 74, manufactured by Sanyo Dye Co., Ltd.), 6 parts of glycerin, 10 parts of a styrene-dimethylaminoethyl acrylate dispersant, and 74 parts of water as a colorant. In a sand mill manufactured by Kanada Rika Kogyo Co., Ltd., dispersion was performed at 1,500 rpm for 5 hours to obtain a pigment dispersion 1-4. In the sand mill, zirconia beads having a diameter of 0.6 mm were used, and the filling rate in the pot was 70%. The styrene-acrylic resin dimethylaminoethyl copolymer cationic dispersion resin used as the dispersant was a copolymer having a copolymerization ratio of 70:30, Mw = 8,000, and an amine value of 170. As this dispersion resin, water and an acetic acid slightly larger than the amine value were added in advance and stirred at 80 ° C. to obtain an aqueous solution. The obtained pigment dispersion liquid 1-4 was stably dispersed with an average dispersion particle diameter of 111 nm, and the polydispersity index was 0.16.

  Next, 100 parts of the above pigment dispersion liquid 1-4 was used, and the following three liquids were respectively charged into a dropping device while being stirred with a motor while being heated to 70 ° C. in a nitrogen atmosphere, and dropped in 6 hours. The polymerization was carried out. The liquid consists of (1) 4.2 parts of benzyl methacrylate, (2) 1.8 parts of dimethylaminoethyl acrylate and 20 parts of water, and (3) 0.05 part of potassium persulfate and 20 parts of water.

  By diluting the obtained dispersion 10 times with water and centrifuging at 5,000 rpm for 10 minutes to remove the agglomerated components, and further centrifuging at 12,500 rpm for 2 hours. Thus, dispersible colorant 1-4 as a sediment was obtained.

  The dispersible colorant 4 obtained above is contained in the ink at a concentration of 4%, and the following component composition is mixed with this and further pressurized with a membrane filter having a pore size of 2.5 microns. Filtration was performed to prepare recording ink 1-4 of this example. The total amount of ink was adjusted with water so as to be 100 parts.

・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: Kawaken Fine Chemical Co., Ltd.) 0.25 part ・ Methyl methacrylate / CH ₂ = C (R ₁ ) COOR ₂ 70/30 Copolymer (made by Starlight Polymer, weight average molecular weight Mw = 7,398)
4 parts [In the above formula, R ₁ = CH ₃ , R ₂ =-(CH ₂ CH ₂ O) ₉ -R ₃ , R ₃ = CH ₃ ]
・ Ion exchange water balance

[Comparative Example 1-1]
The dispersible colorant 1-1 obtained in Example 1 was included in the ink at a concentration of 4%, and the following component composition was mixed therein, and further, a membrane filter having a pore size of 2.5 microns. And pressure-filtered to prepare a recording ink 5 of this comparative example. The total amount of ink was adjusted with water so as to be 100 parts.

・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemical Co., Ltd.) 0.25 parts ・ Ion-exchanged water remaining

[Comparative Example 1-2]
The dispersible colorant 1-2 obtained in Example 2 was contained in the ink at a concentration of 4%, and the following component composition was mixed therein, and further, a membrane filter having a pore size of 2.5 microns. And pressure-filtered to prepare a recording ink 6 containing a water-soluble anionic resin. The total amount of ink was adjusted with water so as to be 100 parts.

・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemicals Co., Ltd.) 0.25 part ・ Styrene / acrylic acid 70/30 copolymer (manufactured by Seiko Polymer Co., Ltd., weight) Average molecular weight Mw = 9,053)
5 parts, remaining ion-exchanged water

[Comparative Example 1-3]
The dispersible colorant 1-3 obtained in Example 3 was contained in the ink at a concentration of 4%, and the following component composition was mixed therein, and the membrane filter having a pore size of 2.5 microns was further added. And pressure-filtered to prepare the recording ink 7 of this example. The total amount of ink was adjusted with water so as to be 100 parts.

・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemicals Co., Ltd.) 0.25 part ・ Styrene / dimethylaminoethyl acrylate 70/30 copolymer (Hoshiko Polymer Co., Ltd.) Manufactured, weight average molecular weight Mw = 7,690) 4 parts, ion-exchanged water remaining

[Characteristics of dispersible colorants]
The dispersible color materials obtained in Examples 1-1 to 1-4 were observed and measured for various physical properties by the methods described below. The glass transition temperature (Tg) of the chargeable resin pseudo fine particles was measured by the following procedure. The dispersible colorant was acidified with hydrochloric acid, the acidified solid was subjected to Soxhlet extraction using THF (tetrahydrofuran), and THF was distilled off to obtain a charged resin pseudo fine particle component. Further, Tg of the obtained chargeable resin pseudo fine particle component was measured by a differential scanning calorimetry (manufactured by METLER, DSC822e). In the case of an aqueous dispersion in which a dispersible colorant and a water-soluble nonionic resin or emulsion coexist, they can be separated using a centrifugal separator. The obtained results are shown in Table 1-1.

<Adhesiveness of resin fine particles>
Each dispersible colorant is dispersed in water and dried, and observed with a scanning electron microscope JSM-6700 (manufactured by JEOL Hitec Co., Ltd.) at a magnification of 50,000 times, and the resin fine particles are fixed to the colorant. The properties of the fixed resin fine particles were evaluated as follows.
○: It was confirmed that resin fine particles were fixed.
X: It was not possible to confirm that the resin fine particles were fixed.

<Dispersion stability>
A 5% aqueous dispersion of each dispersible colorant is diluted 10-fold with pure water, concentrated to the original concentration using an ultrafiltration filter with a molecular weight cut off of 50,000, and the concentrated solution is centrifuged. At 12,000 rpm for 2 hours. The separated sediment is taken out and redispersed in pure water, and is visually dispersed uniformly. The average particle diameter measured by the dynamic light scattering method described later is 2 before the operation. It was confirmed that it was within the range, and evaluated according to the following criteria.
○: Satisfies the conditions.
X: What did not satisfy | fill conditions.

<Long-term storage stability>
For long-term storage stability, each dispersible colorant was placed in a glass sample bottle in the form of a dispersed aqueous solution, and the dispersion state after standing at 60 ° C. for 1 month in a sealed state was judged visually. The evaluation criteria are as follows.
○: No aggregation or sedimentation of solid content is observed.
Δ: Sedimentation of solids is slightly observed, but when shaken lightly, the original uniform dispersion state is restored.
X: Aggregation / sedimentation of solid content is observed, and even if shaken lightly, it does not become uniform.

<Average particle size>
Each dispersible colorant was measured by a dynamic light scattering method using ELS-8000 manufactured by Otsuka Electronics Co., Ltd., and the cumulant average value was defined as the average particle size.

<Surface functional group density>
The surface functional group density of each dispersible colorant was determined as follows. A large excess amount of hydrochloric acid (HCl) is added to the color material aqueous dispersion, and the precipitate settled in a centrifuge at 20,000 rpm for 1 hour is redispersed in pure water, and the solid content is determined to settle. The material was weighed, and a dispersion obtained by adding a known amount of sodium hydrogen carbonate and stirring the mixture was further sedimented in a centrifuge at 80,000 rpm for 2 hours. The supernatant was weighed, and the surface functional group density was calculated by subtracting the blank amount obtained by measuring the known amount of sodium bicarbonate and pure water from the neutralization amount obtained by neutralization titration with 0.1N HCl aqueous solution.

[Evaluation method and evaluation result of water-based inkjet recording ink]
Each recording ink obtained by the above-described method was printed on a glossy recording medium with an ink jet recording apparatus, and the obtained image was evaluated. BJ S600 marketed by Canon Inc. was used as the ink jet recording apparatus used, and glossy paper PR-101 for ink jet recording marketed by Canon Inc. was used as the recording medium. A solid patch of 5 cm square was printed on glossy paper, and the glossiness and scratch resistance (fixability) were evaluated. The results are shown in Table 1-2.

<Glossiness>
The gloss of the printed matter was measured using a microhazemeter (BYK Gardner) and evaluated according to the following criteria.
A: GLOSS value (20 ° glossiness) is 50 or more.
B: The GLOSS value (20 ° gloss) is 40 or more and less than 50.
C: The GLOSS value (20 ° gloss) is 30 or more and less than 40.
D: The GLOSS value (20 ° gloss) is 20 or more and less than 30.

<Abrasion resistance (fixing property)>
The scratch resistance of the printed matter was evaluated based on the following criteria by rubbing the printed portion with Silbon paper having a weight of 40 g / cm ² three times, and visually observing the shaving of the image portion.
A: Although the image is shaved, 90% or more of the printed portion remains.
B: Although the image is shaved, 70% or more of the printed portion remains.
C: The image is greatly sharpened.

  Next, examples in the case of an ink containing emulsion particles will be described.

<Preparation of dispersible colorant>
[Dispersible colorant 2-1]
First, Pigment Blue (PB) 15: 3 (IRIGALITE BLUE 8700 manufactured by Ciba Specialty Chemicals), 6 parts of glycerin, 10 parts of styrene-acrylic acid resin dispersant, and 74 parts of water, In a sand mill manufactured by Kanada Rika Kogyo Co., Ltd., dispersion was carried out at 1,500 rpm for 5 hours to obtain a pigment dispersion 2-1. In the sand mill, zirconia beads having a diameter of 0.6 mm were used, and the filling rate in the pot was 70%. A styrene-acrylic acid resin dispersant having a copolymerization ratio of 70:30, Mw = 8,000, and an acid value of 170 was used. As this styrene-acrylic acid resin dispersant, water and potassium hydroxide equivalent to the above acid value were added in advance and stirred at 80 ° C. to obtain an aqueous solution. The obtained pigment dispersion 2-1 was stably dispersed with an average dispersion particle size of 110 nm, and the polydispersity index was 0.16.

  Next, 100 parts of the pigment dispersion 2-1 obtained above was heated to 70 ° C. in a nitrogen atmosphere, and the following three liquids were respectively charged into the dropping device while stirring with a motor for 6 hours. The polymerization was carried out dropwise. The solution was (1) 5.5 parts methyl methacrylate, (2) 0.5 parts acrylic acid, 0.25 parts potassium hydroxide and 20 parts water, (3) 0.05 parts potassium persulfate and 20 parts water. Consists of parts.

  The obtained dispersion was diluted 10-fold with water and centrifuged at 5,000 rpm for 10 minutes to remove the aggregating component. Then, it further refine | purified by centrifuging on conditions of 12,500 rpm and 2 hours, and the dispersible color material 2-1 which is a sediment was obtained.

  This dispersible colorant 2-1 is dispersed in water, centrifuged at 12,000 rpm for 60 minutes, and the precipitate redispersed in water is dried, and then scanned with an electron microscope JSM-6700 (Japan) When observed at 50,000 times by Electronic Hitech Co., Ltd., it was observed that the chargeable resin pseudo fine particles smaller than the color material carbon black were fixed on the surface of the carbon black. In addition, also about the color material after this described in a present Example, the form of the color material was confirmed with the method similar to the above.

[Dispersible colorant 2-2]
Using 100 parts of the pigment dispersion 2-1 obtained above, while heating to 70 ° C. in a nitrogen atmosphere, the following three liquids were charged into a dropping device while being stirred with a motor, and dropped in 6 hours. In addition, polymerization was performed. The liquid was (1) 4.5 parts benzyl methacrylate, 1.2 parts butyl acrylate, (2) 0.3 parts acrylic acid, 0.15 parts potassium hydroxide and 20 parts water, (3) persulfuric acid. It consists of 0.05 part of potassium and 20 parts of water.

  By diluting the obtained dispersion 10 times with water and centrifuging at 5,000 rpm for 10 minutes to remove the agglomerated components, and further centrifuging at 12,500 rpm for 2 hours. A dispersible colorant 2-2 as a sediment was obtained.

[Dispersible colorant 2-3]
Using 100 parts of the pigment dispersion 2-1 obtained above, while heating to 70 ° C. in a nitrogen atmosphere, the following three liquids were charged into a dropping device while being stirred with a motor, and dropped in 6 hours. In addition, polymerization was performed. (1) benzyl methacrylate 5.0 parts, butyl acrylate 0.7 parts, (2) acrylic acid 0.3 parts, potassium hydroxide 0.15 parts and water 20 parts (3) potassium persulfate It consists of 0.05 part and 20 parts of water.

  By diluting the obtained dispersion 10 times with water and centrifuging at 5,000 rpm for 10 minutes to remove the agglomerated components, and further centrifuging at 12,500 rpm for 2 hours. Thus, dispersible colorant 2-3 which is a sediment was obtained.

[Dispersible colorant 2-4]
Using 100 parts of the pigment dispersion 2-1 obtained above and heating to 70 ° C. in a nitrogen atmosphere, the following three liquids were respectively charged into a dropping device while stirring with a motor and dropped in 6 hours. The polymerization was carried out. The liquid was (1) butyl acrylate. 5.0 parts, 0.7 parts of benzyl methacrylate, (2) 1.8 parts of dimethylaminoethyl acrylate and 20 parts of water, (3) 0.05 part of potassium persulfate and 20 parts of water.

  By diluting the obtained dispersion 10 times with water and centrifuging at 5,000 rpm for 10 minutes to remove the agglomerated components, and further centrifuging at 12,500 rpm for 2 hours. Thus, dispersible colorant 2-4 as a precipitate was obtained.

[Dispersible colorant 2-5]
Using 100 parts of the pigment dispersion 2-1 obtained above and heating to 70 ° C. in a nitrogen atmosphere, the following three liquids were respectively charged into a dropping device while stirring with a motor and dropped in 6 hours. The polymerization was carried out. The liquid consists of (1) 5.7 parts of butyl acrylate, (2) 1.8 parts of dimethylaminoethyl acrylate and 20 parts of water, and (3) 0.05 part of potassium persulfate and 20 parts of water.

  By diluting the obtained dispersion 10 times with water and centrifuging at 5,000 rpm for 10 minutes to remove the agglomerated components, and further centrifuging at 12,500 rpm for 2 hours. Thus, dispersible colorant 2-5 as a precipitate was obtained.

<Preparation of emulsion particles>
[Emulsion particles 1]
Emulsion particles 1 were prepared as follows. Under a nitrogen atmosphere, 100 parts of the 2% aqueous solution of the styrene-acrylic acid resin dispersant described above was heated to 70 ° C., and the following three liquids were charged into the dropping device while stirring with a motor for 6 hours. The polymerization was carried out dropwise. The liquid was (1) methyl methacrylate 5.5 parts, (2) acrylic acid 0.5 parts, potassium hydroxide 0.25 parts and water 20 parts, (3) potassium persulfate 0.05 parts and water 20 Consists of parts.

  The obtained dispersion was purified by centrifuging at 80,000 rpm for 2 hours to obtain emulsion particles 1 as a precipitate. Emulsion particle 1 had an average dispersed particle size of 20 nm.

[Emulsion particles 2]
Emulsion particles 2 were obtained in the same manner as the preparation of emulsion particles 1 except that 4.5 parts of benzyl methacrylate and 1.0 part of butyl acrylate were used instead of 5.5 parts of methyl methacrylate.

[Emulsion particles 3]
Emulsion particles 3 were obtained in the same manner as in the preparation of emulsion 1 except that 0.7 parts of benzyl methacrylate and 4.8 parts of butyl acrylate were used instead of 5.5 parts of methyl methacrylate.

[Emulsion particles 4]
Emulsion particles 4 were obtained in the same manner as the preparation of emulsion 1 except that 5.0 parts of benzyl methacrylate and 0.5 parts of butyl acrylate were used instead of 5.5 parts of methyl methacrylate.

[Emulsion particles 5]
Emulsion particles 5 were obtained in the same manner as the preparation of the emulsion 1 except that 5.5 parts of butyl acrylate was used instead of 5.5 parts of methyl methacrylate.

[Emulsion particles 6 and 7]
While stirring with a motor in a state where 100 parts of pure water was heated to 70 ° C. in a nitrogen atmosphere, each of the following three liquids was charged into a dropping device and dropped in 6 hours for polymerization. The liquid was (1) 4.5 parts benzyl methacrylate, 1 part butyl acrylate, (2) 0.5 parts acrylic acid, 0.25 parts potassium hydroxide and 20 parts water, (3) 0 potassium persulfate. .05 parts and 20 parts of water.

  The obtained dispersion was classified by centrifugation to obtain emulsion particles 6 and emulsion particles 7. The average dispersed particle size of the emulsion particles 6 was 80 nm, and the average particle size of the emulsion particles 7 was 120 nm.

[Emulsion particles 8]
Emulsion particles 8 were prepared as follows. In a nitrogen atmosphere, 100 parts of the 2% aqueous solution of styrene-dimethylaminoethylethyl acrylate resin dispersant described above was added to each of the following three liquids while stirring with a motor while heating to 70 ° C. Then, it was added dropwise in 6 hours to carry out polymerization. The liquid was (1) butyl acrylate 4.5 parts, benzyl methacrylate 1.2 parts, (2) dimethylaminoethyl acrylate 1.8 parts and water 20 parts, (3) potassium persulfate 0.05 parts. And 20 parts of water.

  The obtained dispersion was purified by centrifuging at 80,000 rpm for 2 hours to obtain emulsion particles 8 as a precipitate. Emulsion particles 8 had an average dispersed particle size of 60 nm.

[Example 2-1]
A recording ink 2-1 according to Example 2-1 was produced in the following manner. The dispersible colorant 2-2 is contained in the ink at a concentration of 4%, and the following component composition is mixed with this, and further filtered under pressure with a membrane filter having a pore size of 2.5 microns, A recording ink 2-1 of this example was prepared.
・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemicals Co., Ltd.) 0.25 part ・ Emulsion particles 1 4 parts ・ Ion-exchanged water remaining (100 parts in total) )

[Example 2-2]
A recording ink 2-2 was prepared in the same manner as in Example 1 except that 4 parts of the emulsion particle 2 was used instead of the emulsion particle 1.

[Example 2-3]
A recording ink 2-3 was prepared in the same manner as in Example 1 except that 4 parts of the emulsion particles 3 were used in place of the emulsion particles 1.

[Example 2-4]
A recording ink 2-4 was prepared in the same manner as in Example 1 except that 4 parts of the emulsion particles 4 were used in place of the emulsion particles 1.

[Example 2-5]
A recording ink 2-5 was prepared in the same manner as in Example 1 except that 4 parts of the emulsion particles 5 were used in place of the emulsion particles 1.

[Example 2-6]
A recording ink 2-6 was prepared in the same manner as in Example 1 except that 0.2 part of the emulsion particle 2 was used instead of the emulsion particle 1.

[Example 2-7]
A recording ink 2-7 was prepared in the same manner as in Example 1 except that 0.2 part of the emulsion particle 6 was used instead of the emulsion particle 1.

[Example 2-8]
A recording ink 2-8 was obtained in the same manner as in Example 1 except that 0.2 part of the emulsion particle 7 was used instead of the emulsion particle 1.

[Example 2-9]
The recording ink 2- was prepared in the same manner as in Example 1 except that the dispersible colorant 2-5 was used instead of the dispersible colorant 2-2, and that 4 parts of the emulsion particles 8 were used instead of the emulsion particles 1. 9 was obtained.

[Example 2-10]
A recording ink 2-10 was prepared in the same manner as in Example 2-1, except that the dispersible colorant 2-1 was used instead of the dispersible colorant 2-2.

[Example 2-11]
A recording ink 2-11 was prepared in the same manner as in Example 2-1, except that the dispersible colorant 2-3 was used instead of the dispersible colorant 2-2.

[Example 2-12]
A recording ink 2-12 was prepared in the same manner as in Example 2-1, except that the dispersible color material 2-4 was used instead of the dispersible color material 2-2.

[Comparative Example 2-1]
The dispersible colorant 2-2 is contained in the ink at a concentration of 4%, and the following component composition is mixed with this, and pressure filtration is performed with a membrane filter having a pore size of 2.5 microns. Then, a recording ink 2-13 of this example was prepared.
・ Glycerol 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 5 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemicals Co., Ltd.) 0.25 part ・ Ion-exchanged water remaining (amount to be 100 parts in total)

《Dispersible colorant properties》
Each dispersible colorant was observed and measured for various physical properties by the methods described below, and the glass transition temperature (Tg) of the chargeable resin pseudo fine particles was measured by the following procedure. The dispersible colorant was acidified with hydrochloric acid, the acidified solid was subjected to Soxhlet extraction using THF (tetrahydrofuran), and THF was distilled off to obtain a charged resin pseudo fine particle component. Further, Tg of the obtained chargeable resin pseudo fine particle component was measured by a differential scanning calorimetry (manufactured by METLER, DSC822e). In the case of an aqueous dispersion in which a dispersible colorant and a water-soluble nonionic resin or emulsion coexist, they can be separated using a centrifugal separator. The obtained results are shown in Table 2-1.

<Adhesiveness of resin fine particles>
Each dispersible colorant is dispersed in water and dried, and observed with a scanning electron microscope JSM-6700 (manufactured by JEOL Hitec Co., Ltd.) at a magnification of 50,000 times, and the resin fine particles are fixed to the colorant. The properties of the fixed resin fine particles were evaluated as follows.

(Adhesive state of resin fine particles)
○: It was confirmed that resin fine particles were fixed.
X: It was not possible to confirm that the resin fine particles were fixed.

<Dispersion stability>
A 5% aqueous dispersion of each dispersible colorant is diluted 10-fold with pure water, concentrated to the original concentration using an ultrafiltration filter with a molecular weight cut off of 50,000, and the concentrated solution is centrifuged. At 12,000 rpm for 2 hours. The separated sediment is taken out and redispersed in pure water, and is visually dispersed uniformly. The average particle diameter measured by the dynamic light scattering method described later is 2 before the operation. It was confirmed that it was within the range, and evaluated according to the following criteria.
○: Satisfies the conditions.
X: What did not satisfy | fill conditions.

<Long-term storage stability>
For long-term storage stability, each dispersible colorant was placed in a glass sample bottle in the form of a dispersed aqueous solution, and the dispersion state after standing at 60 ° C. for 1 month in a sealed state was judged visually. The evaluation criteria are as follows.
○: No aggregation or sedimentation of solid content is observed.
Δ: Sedimentation of solids is slightly observed, but when shaken lightly, the original uniform dispersion state is restored.
X: Aggregation / sedimentation of solid content is observed, and even if shaken lightly, it does not become uniform.

<Average particle size>
Each dispersible colorant and emulsion particles were measured by a dynamic light scattering method using ELS-8000 manufactured by Otsuka Electronics Co., Ltd., and the cumulant average value was defined as the average particle size.

<Surface functional group density>
The surface functional group density of each dispersible colorant was determined as follows. A large excess amount of hydrochloric acid (HCl) is added to the color material aqueous dispersion, and the precipitate settled in a centrifuge at 20,000 rpm for 1 hour is redispersed in pure water, and the solid content is determined to settle. The material was weighed, and a dispersion obtained by adding a known amount of sodium hydrogen carbonate and stirring the mixture was further sedimented in a centrifuge at 80,000 rpm for 2 hours. The supernatant was weighed and the surface functional group density was calculated by subtracting the blank value obtained by measuring the known amount of sodium hydrogen carbonate and pure water from the neutralization amount obtained by neutralization titration with 0.1 N hydrochloric acid aqueous solution. When it has an amine value, it can be calculated by using a known amount of aqueous hydrochloric acid and 0.1N potassium hydroxide instead of sodium hydrogen carbonate and 0.1N aqueous hydrochloric acid.

<Characteristics of emulsion particles>
Each emulsion particle obtained as described above was measured for an average particle size by a particle size measuring device (FPAR1000 manufactured by Otsuka Electronics Co., Ltd.). Further, the glass transition temperature of the emulsion particles was measured by differential scanning calorimetry (DSC822e manufactured by METTTLER) of the emulsion water dispersion obtained by evaporation to dryness. The results are shown in Table 2-2.

[Evaluation method and evaluation result of water-based inkjet recording ink]
Each of the recording inks of Examples and Comparative Examples obtained by the method described above was printed on a glossy recording medium with an inkjet recording apparatus, and the obtained images were evaluated. BJ S600 marketed by Canon Inc. was used as the ink jet recording apparatus used, and glossy paper PR-101 for ink jet recording marketed by Canon Inc. was used as the recording medium. A solid patch of 5 cm square was printed on glossy paper, and the glossiness and scratch resistance (fixability) were evaluated. The results are shown in Tables 2-3 to 2-5.

<Glossiness>
The gloss of the printed matter was measured using a microhazemeter (BYK Gardner) and evaluated according to the following criteria.
A: GLOSS value (20 ° glossiness) is 50 or more.
B: The GLOSS value (20 ° gloss) is 40 or more and less than 50.
C: The GLOSS value (20 ° gloss) is 30 or more and less than 40.
D: The GLOSS value (20 ° gloss) is 20 or more and less than 30.

<Abrasion resistance (fixing property)>
The scratch resistance of the printed matter was evaluated based on the following criteria by rubbing the printed portion with Silbon paper having a weight of 40 g / cm ² three times, and visually observing the shaving of the image portion.
A: Although the image is shaved, 90% or more of the printed portion remains.
B: Although the image is scraped, 70% or more and less than 90% of the printed portion remains.
C: The image is greatly scraped (remaining less than 70%).

  From the above results, the glossiness and scratch resistance were improved by using the water-based ink in which the emulsion was added to the dispersible colorant. Furthermore, at least one of glossiness and abrasion resistance is further improved by using an emulsion having a glass transition temperature in the range of −40 ° C. to 60 ° C. or an emulsion particle having an average particle size in the range of 10 nm to 80 nm. did.

  According to the present invention, an image having high dispersion stability, excellent long-term dispersion stability, and excellent fastness such as scratch resistance can be obtained, and particularly suitable for inkjet recording from which a highly glossy image can be obtained. Water-based ink is provided. In addition, according to the present invention, an ink tank, an ink jet recording apparatus, an ink jet recording method, and an ink jet recorded image capable of providing such an excellent image are provided.

It is a schematic diagram which shows the basic structure of the dispersible coloring material which has fused the flat chargeable resin pseudo fine particles according to the present invention. It is a schematic diagram of the typical process in the manufacturing method of this invention. It is a schematic diagram which shows the refinement | purification of the flat chargeable resin pseudo fine particles and the fusion process to a color material in the manufacturing method of this invention. It is the schematic diagram which expanded the chargeable resin pseudo fine particle of this invention from the interface side fuse | melted with a coloring material. It is the schematic diagram which expanded the interface where the chargeable resin pseudo fine particles of the present invention and the color material are fused. It is a schematic diagram of a pigment peeling phenomenon when a hydrophilic group is directly modified on an organic pigment, represented by Patent Document 1. FIG. 4 is a schematic diagram illustrating a state in which a water-soluble nonionic resin forms a film in a gap between dispersible color materials on a recording medium. It is a schematic diagram showing a state where emulsion particles form a film in a gap between dispersible color materials on a recording medium.

Explanation of symbols

1: Color material 2: Flat chargeable resin pseudo fine particles 3: Dispersant 4: Monomer 5: Polymerization initiator aqueous solution 6: Dispersible color material 7: Oligomer formed by polymerization of monomer 8: Oligomer insolubilized in water Deposit 9-1: Hydrophilic monomer unit portion 9-2 in the flat charged resin pseudo fine particle 9-2: Hydrophobic monomer unit portion 10 in the flat charge resin pseudo fine particle 10: Bonding site 11 with the color material 11: Flat Interfacial portion of colored chargeable resin pseudo fine particles with color material 12: hydrophilic group 13 directly modified to color material 13: hydrophilic color material molecule 14: recording medium 15-1: water-soluble nonionic resin 15-2: Film formation with water-soluble nonionic resin 16-1: Particulate emulsion 16-2: Emulsion with crushed particles 16-3: Emulsion with fluidity 16-4: Film formation with emulsion

Claims (15)

  A dispersible color material comprising a color material and a chargeable resin pseudo fine particle smaller than the color material, and the color material and the charge resin pseudo fine particle fixed together, a water-soluble nonionic resin, and emulsion particles An aqueous ink comprising at least one selected from the group consisting of:   The water-based ink according to claim 1, wherein the dispersible colorant has a surface functional group density of 250 μmol / g or more and less than 1,000 μmol / g.   The water-based ink according to claim 1 or 2, wherein the resin constituting the chargeable resin pseudo fine particles has a glass transition temperature of -40 ° C or higher and 60 ° C or lower.   The dispersible colorant is an aqueous radical polymerization initiator in an aqueous solution in which a water-insoluble colorant is dispersed, and a chargeable resin pseudo fine particle that generates a radical polymerizable monomer by aqueous precipitation polymerization and the water-insoluble colorant. The water-based ink according to any one of claims 1 to 3, which is a dispersible color material produced by integrating the ink.   The water-based ink according to any one of claims 1 to 4, wherein the water-soluble nonionic resin has a weight average molecular weight Mw of 2,000 to 10,000.   The water-based ink according to any one of claims 1 to 5, wherein the water-soluble nonionic resin is contained in an amount of 1% by mass or more in the ink.   The water-based ink according to any one of claims 1 to 4, wherein the emulsion particles are electrically homogeneous or nonionic with the chargeable resin pseudo fine particles.   The water-based ink according to any one of claims 1 to 4 and 7, wherein an average particle diameter of the emulsion particles is 10 to 80 nm.   The water-based ink according to any one of claims 1 to 4, 7, and 8, wherein the emulsion particles are contained in an amount of 0.1% by mass or more in the ink.   The water-based ink according to any one of claims 1 to 4 and 7 to 9, wherein the emulsion particles have a glass transition temperature of -40 ° C or higher and 60 ° C or lower.   The water-based ink according to any one of claims 1 to 10, which is for inkjet recording.   An ink tank comprising the water-based ink according to claim 11.   An ink jet recording apparatus that forms an ink jet recording image using the water-based ink according to claim 11.   An ink jet recording method comprising forming an image by an ink jet recording apparatus using the water-based ink according to claim 11. An ink jet recording image formed by an ink jet recording apparatus using the water-based ink according to claim 11.

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