JP2006008903A - Ink for recording, recording method using the same, ink jet recording apparatus, and ink jet recorded image - Google Patents

Abstract

A recording ink suitable for inkjet recording, in particular, for obtaining a recorded image having high print density and gloss on a recording medium, particularly on glossy paper, and excellent fixability (rapid drying property) on the recording paper, and the like A recording method, an ink jet recording apparatus, and an ink jet recorded image.
A recording ink (A) for forming a recording image used in an ink recording method for applying a liquid composition (B) containing a resin component after forming a recording image, the ink (A) comprising: A recording ink comprising a color material, and a dispersible color material composed of chargeable resin pseudo fine particles smaller than the color material and fixed to the color material, a recording method using the same, and an ink jet recording apparatus And inkjet recording images.
[Selection] Figure 1

Description

  The present invention relates to an ink recording method in which a liquid composition is applied after forming a recorded image, and particularly to a recording ink suitable for inkjet recording, a recording method using the same, an inkjet recording apparatus, and an inkjet recorded image.

  The ink jet recording method is a method for recording images, characters, etc. by ejecting micro droplets of ink from nozzles to reach a recording medium (paper, etc.) based on various operating principles. Are easy to use, have high flexibility in recording patterns, and do not require development and fixing operations, and are rapidly spreading in various applications. In particular, in recent years, full-color, ink-jet recording technology using water-based ink has made remarkable progress, and multicolor images that are comparable to multicolor printing by conventional plate making methods and printing by color photographic methods. It is also possible to form. Furthermore, when the number of copies is small, printed matter can be obtained at a lower cost than ordinary multicolor printing or printing, so the ink jet recording system is being 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 have been made to ink jet recording apparatuses and recording methods. In general, the performance required for the ink for ink jet recording used in the 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 the paper; 2) Clogging due to ink drying at the nozzle tip does not occur, and ejection responsiveness and ejection stability are always good. (3) Ink fixability is good on paper. (4) Image robustness. Properties (that is, weather resistance, water resistance, etc.) and (5) good long-term storage stability.

  In addition, with the recent increase in the definition of printed images, the development of photographic image quality by the ink jet recording method has been promoted, and not only for plain paper but also for special recording media such as glossy paper, ink drying and There is a demand for ink that can be fixed quickly and that can provide high-quality printing. In response to such demands, as a coloring material for water-based inkjet recording inks that can realize higher weather resistance and water resistance of images, the development of coloring materials that are essentially insoluble in water, especially inks using pigments, has been energetically developed. It is being advanced. Furthermore, as a recent trend, in order to obtain a better ink jet image, not only the water-insoluble coloring material is stably dispersed in the ink, but also the obtained printed matter has an excellent image quality. There is a demand for achieving both excellent scratch resistance.

  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 an aqueous medium. When a water-insoluble colorant is used as an ink for ink jet recording, it is generally dispersed and stabilized using a surfactant or a polymer dispersant (also referred to as a dispersion resin), but the dispersion resin has an affinity for water. Therefore, there is a problem in that it is easily detached from the surface of the color material and sufficient stability cannot be maintained for a long time. Also, water-based inkjet recording ink containing a water-soluble polymer component such as a dispersion resin is likely to stick around or inside the nozzle of an inkjet recording apparatus, which may change the size and direction of the ejected ink droplets. In particular, it has become a problem when obtaining high-definition images.

  Therefore, a method of chemically modifying (reforming) the surface of the water-insoluble colorant so as to stably disperse without containing a dispersion resin or a surfactant has been studied. For example, an aqueous pigment ink using a self-dispersing carbon black in which a hydrophilic group is bonded to the surface of carbon black directly or through another atomic group as a coloring material has been proposed (for example, see Patent Document 1). Such a surface chemical modification pigment is called a self-dispersion pigment and does not require a water-soluble resin or the like, and thus exhibits good ink jet ejection stability. However, according to the study by the present inventors, the adhesive strength of the coloring material to the recording paper is weak because it does not contain the dispersion resin. In particular, an image with a high print density on a glossy paper medium is resistant to the recording paper. In addition to being inferior in rubbing properties, the image was not glossy and the image density tended to decrease.

  On the other hand, development of microcapsule type pigments that are useful for ink jet recording inks and that coat pigments with resins has been underway (see, for example, Patent Document 2). Also in this case, in order to obtain sufficient dispersion stability in the aqueous medium, it is necessary to increase the hydrophilicity of the resin being coated. However, according to the study by the present inventors, if the hydrophilicity of the resin is increased, the resin tends to be detached from the pigment surface or the viscosity of the ink is increased. It became clear that it was difficult to balance with sex.

  For the purpose of improving the glossiness of an image, a recorded image forming method is disclosed in which a top coat layer is formed after an image is formed on a recording medium by an inkjet method (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 10-195360 JP-A-8-183920 JP 2002-201428 A

  However, as a result of further investigation by the present inventors on the technique described in Patent Document 3 listed above, an image obtained in this case requires a long time to obtain satisfactory and sufficient scratch resistance and glossiness. In addition, the fixing property of the image at an early stage was not satisfactory. In other words, no means has yet been achieved for obtaining a recorded image having excellent fixing properties and scratch resistance of the recorded image and sufficient quality in terms of print quality, particularly on glossy paper.

  Accordingly, the object of the present invention is to solve these problems and obtain a recorded image having high print density and glossiness on a recording medium, particularly glossy paper, and excellent fixability (fast drying property) on the recording paper. In particular, a recording ink suitable for inkjet recording, a recording method using the same, an inkjet recording apparatus, and an inkjet recorded image are provided.

  As a means for solving the above-mentioned problems, the present inventors combined an ink containing a novel dispersible colorant and a liquid composition containing a resin component to achieve excellent quick drying, high print density and gloss. Inkjet recording images with good properties were obtained. That is, the present invention is achieved by the following means.

1. A recording ink (A) for forming a recording image used in an ink recording method for applying a liquid composition (B) containing a resin component after forming a recording image, the ink (A) comprising a colorant, A recording ink comprising a dispersible color material which is smaller than the color material and is composed of chargeable resin pseudo fine particles fixed to the color material.
2. 2. The recording ink according to 1 above, wherein the chargeable resin pseudo fine particles have an anionic property.
3. 2. The recording ink according to 1 above, wherein the chargeable resin pseudo fine particles have a cationic property.

4). A step (I) of applying a recording ink (A) having a dispersible color material comprising a color material and a chargeable resin pseudo fine particle smaller than the color material and fixed to the color material on a recording medium; And at least a step (II) of applying a liquid composition (B) containing a resin component on a recording image of the recording ink (A), and performing the step (II) following the step (I). A recording method characterized by the above.
5. 5. The recording method as described in 4 above, wherein the resin component contained in the liquid composition (B) is a cationic water-soluble resin.
6). 5. The recording method as described in 4 above, wherein the resin component contained in the liquid composition (B) is an anionic water-soluble resin.
7). 5. The recording method as described in 4 above, wherein the resin component contained in the liquid composition (B) is an emulsion.

8). An ink jet recording apparatus comprising the recording ink according to any one of the above items 1 to 3.
9. An ink jet recorded image formed by an ink jet recording apparatus using the recording method according to any one of 5 to 7 above.

  According to the present invention, there is provided a recording ink (A) comprising a dispersible color material having a color material and a chargeable resin pseudo fine particle smaller than the color material and fixed to the color material. After the image is formed, by applying the liquid composition (B) containing the resin component, it is possible to obtain high image density and gloss, and further quick drying.

  The mechanism that gives the above effect is considered as follows. FIG. 7 shows a state in which a recording ink (A) containing a dispersible color material is printed on a special medium. When the recording ink (A) according to the present invention reaches the recording medium, the ink solvent is a pore on the recording medium due to capillary action (in the case of plain paper, it is a gap between cellulose fibers; coated paper or glossy paper) 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 because of the morphological features (details will be described later), because the chargeable resin pseudo fine particles 2 are scattered at portions where the color materials 1 are in contact with each other. Capillary action acts on the ink solvent that is formed and exists between the color materials. For this reason, the ink solvent between the color materials is quickly absorbed into the recording medium. As a result, it is considered that quick drying is obtained. However, particularly glossy paper and the like have quick drying properties, but glossiness and image density may be insufficient. When color material components such as glossy paper remain on the recording medium, the shape of the surface of the recorded image may be uneven, and it is assumed that irregular reflection of light has an effect on glossiness and image density due to the unevenness. It was.

  By printing the liquid composition (B) containing the resin component on the surface of the recorded image, the resin fills the unevenness of the printing dots, and irregular reflection is suppressed, and glossiness and image density are improved. Since the recorded image formed by the dispersible color material has many fine gaps, the liquid composition (B) containing the resin component applied on the image is uniformly diffused and uneven by the resin. Therefore, printed dots with high smoothness are obtained. Furthermore, since the liquid composition (B) permeates the fine gaps formed by the dispersible colorant of the recording ink (A) by capillary action, it is considered that quick drying is imparted.

  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. A feature of the present invention is that recording is performed with a recording ink (A) characterized by having a dispersible color material having a color material and charged resin pseudo fine particles smaller than the color material and fixed to the color material. After the image is formed, a liquid composition (B) containing a resin component (hereinafter referred to as a liquid composition (B)) is applied.

  The method for applying the recording ink (A) and the liquid composition (B) onto the recording medium includes the step of first applying the recording ink (A) onto the recording medium, and then at least the recording ink (A). There is no particular limitation as long as it is applied in the order of the steps of applying the liquid composition (B) to the recording part according to. For example, a method of printing the liquid composition (B) on a recording medium immediately after forming an image with the recording ink (A) on the recording medium in an ink jet recording system, or a recording ink (A) and a liquid composition Examples include a method in which each ink tank is set in the carriage and the object (B) is printed in the order of the recording ink (A) and the liquid composition (B). Further, the portion to which the liquid composition (B) is applied on the recording medium is not particularly limited as long as it is applied to at least the image portion of the recording ink (A). The liquid composition (B) may be applied only to the recording portion of the recording ink (A) or to the entire recording medium.

  Next, each component of the recording ink (A) according to the present invention and the liquid composition (B) used together with the ink (A) will be described.

<Ink for recording (A)>
The recording ink (A) according to the present invention includes at least a dispersible color material and an aqueous medium, and the dispersible color material has a color material and chargeable resin pseudo fine particles smaller than the color material. In addition, the chargeable resin pseudo fine particles are fixed to the coloring material, and can be dispersed alone in an aqueous medium.

[Dispersible colorant]
Hereinafter, the dispersible colorant, which is an essential component of the recording ink (A) according to the present invention, will be described in detail. The first characteristic of the dispersible color material used in the present invention is that the color material contained in the recording ink (A) is composed of a color material and charged resin pseudo fine particles, and is formed on the surface of the color material. The chargeable resin pseudo fine particles are fixed. Therefore, in the present invention, it is preferable to use a water-insoluble color material such as a pigment as the color material.

  FIG. 1 is a schematic diagram of a dispersible colorant that characterizes the present invention. In the figure, 1 is a color material and 2 is a chargeable resin pseudo fine particle, but a charge resin pseudo fine particle 2 smaller than the color material 1 is fixed to the particle surface of the 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 on the particle surface of the coloring material 1 is fused.

  As shown in FIG. 1, the chargeable resin pseudo fine particles 2 are fixed to the particle surface of the coloring material 1, whereby the charge of the chargeable resin pseudo fine particles 2 is applied to the particle surface of the coloring material 1, and water or water and It becomes a dispersible colorant that can be dispersed alone in an aqueous medium composed of a water-soluble organic medium. At the same time, the dispersible color material has excellent adhesion to the recording medium due to the presence of the resin component fixed to the color material surface. At this time, the dispersible colorant used in the present invention is not a simple physical adsorption of the resin component to the surface of the colorant particle, but the charged resin pseudo fine particles described below are fixed to the surface of the colorant particle. Therefore, the chargeable resin pseudo fine particles are not detached from the color material surface, and the ink has excellent long-term storage stability.

  Here, the “chargeable resin pseudo fine particle” in the present specification is a resin aggregate in which the resin component is strongly aggregated, and preferably has many physical crosslinks formed therein, and the resin aggregate Has a stable form as a fine particle form or a microaggregate close thereto. Details of the chargeable resin pseudo fine particles will be described later.

  The fixing state of the coloring material and the chargeable resin pseudo fine particles in the present invention is due to a strong interaction between the color material surface and the chargeable resin pseudo fine particles, and is considered to be in the following state. FIG. 4 shows a schematic diagram in which the interface between the chargeable resin pseudo fine particles and the color material is enlarged. First, as shown in FIG. 4, at the interface with the colorant 1, the chargeable resin pseudo fine particles 2 are polymers composed of various monomer unit compositions (indicated by 9-1 and 9-2 in the figure). Are intertwined. At this time, the polymer has various structures locally, and the surface energy state is distributed. At the point where the surface energy resulting from the chemical structure and surface structure of the colorant and the surface energy resulting from the chemical structure and surface structure of the polymer are in good agreement locally (indicated by 10 in the figure), the two interfaces are It will be firmly bonded. Furthermore, at the interface where one chargeable resin pseudo fine particle is in contact with the color material, as shown in FIG. 4, there are a plurality of points where the surface energies as indicated by 10 are locally coincident. It is expected that the fixed state of the present invention is established by the interaction.

  In particular, the inside of the chargeable resin pseudo fine particles has a strong interaction between the constituent polymers, and in some cases, the constituent polymers are entangled with each other to form physical crosslinks. Even when there are many hydrophilic groups, the fixed chargeable resin pseudo fine particles are not detached from the coloring material, and the resin component having hydrophilic groups does not continue to elute from the chargeable resin pseudo fine particles. .

  In addition, the dispersible color material used in the present invention has an advantage that the chargeable resin pseudo fine particles are fixed to the color material surface. As a result, the specific surface area of the dispersible color material increases depending on the form (see FIG. 4). It is possible to distribute the charge of the charged resin pseudo fine particles on the surface in many parts. When the dispersible color material has a high specific surface area, 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 color material surface, and the color material represented by Patent Document 2 is coated with a resin. High dispersion stability can be imparted even when the substantial acid value or amine value of the resin component is smaller than that of the form.

  In the present invention, it is confirmed that the color material is a dispersible color material in which the chargeable resin pseudo fine particles are “fixed” in a simple manner using the following three-stage separation method. can do. 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 in the second separation. Thus, the coloring material and the water-insoluble resin component contained in the precipitate in the first separation are separated. Further, in the third separation, the weakly adsorbed resin component is separated from the dispersible colorant to which the chargeable resin pseudo fine particles are fixed, and the resin component contained in the third separation supernatant is determined. Then, the adhesion between 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, and adjust the total solid content to about 10%. 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. Re-disperse the sediment in 3 volumes of pure water. 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. It was confirmed that the observed dispersible colorant had a plurality of fine particle-like substances or micro-aggregates equivalent thereto attached to the surface, and the same sediments from the second separation and the third separation were the same. If it has this 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 can be judged that the resin pseudo fine particles are not detached from the dispersible color material, and 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 the dispersible color material used in the above. That is, in the first separation, the purpose is to separate the coloring material contained in the ink and the water dispersion and the resin component adsorbed thereto, and the water-soluble component. In the second separation, The purpose is to separate the color material and the resin component adhering to the color material from other resin components adsorbed on the color material. Furthermore, the third separation is intended to confirm that the resin component adhering to the colorant is not desorbed. Of course, any other separation method known or newly developed may be used as long as it achieves the purpose of each of the first, second, and third separations. It is applicable at least.

  As described above, the second feature of the dispersible color material used in the present invention is that the color material 1 can be dispersed in an aqueous medium alone with the chargeable resin pseudo fine particles 2 fixed thereto. There is a point. As described above, the dispersible colorant used in the present invention is essentially a self-dispersing agent that can be stably dispersed in water or water-based ink without the aid of other surfactants or polymer dispersants. The color material of the mold. 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 time for the purpose of stabilizing the dispersion of the colorant. There is no need to do. As a result, when such a dispersible color material is used as a water-based ink, the degree of freedom in designing with respect to components other than the dispersible color material is increased, for example, on a recording medium having high ink permeability such as plain paper. In this case, the water-based ink can obtain a sufficiently high printing density.

  The self-dispersibility of the dispersible colorant used in the present invention can be confirmed by, for example, the following method. 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 by a centrifugal separator at 80,000 rpm for 90 minutes, and the sediment is taken out and redispersed in pure water. At this time, it is determined that the precipitate that can be redispersed 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. When used as an ink, excellent dispersion stability (storage stability) is achieved. Therefore, the chargeable resin pseudo fine particles are many scattered and fixed to the color material, so that a more preferable result can be obtained. In particular, it is desirable that there is a certain distance between the chargeable resin pseudo fine particles fixed to the color material, preferably uniformly distributed, and more preferably, the particle surface of the color material is partially exposed. Such a state can be confirmed by observing the dispersible colorant used in 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. If the state is observed, it can be said that it is a dispersible colorant used in the present invention. In addition, the charged resin pseudo fine particles are sometimes close to each other, and in some cases, may be observed to be fused, 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, the charged resin pseudo fine particles are considered to be scattered and fixed to the color material. Will be apparent to those skilled in the art.

  According to the study by the present inventors, it has been clarified that the recording ink according to the present invention containing the dispersible colorant as described above exhibits an excellent quick drying property 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 a pore on the recording medium due to capillary action (in the case of plain paper, it is a gap between cellulose fibers, coated paper and glossy In the case of paper, it is absorbed into the pores of the receiving layer). At this time, the color material used in the present invention has many fine gaps between the color materials because of the morphological characteristics of the color material. Capillary action acts on the ink solvent. For this reason, the ink solvent between the color materials is quickly absorbed into the recording medium. Among the dispersible color materials used in the present invention, those having a form in which charged resin pseudo fine particles are scattered on the surface give a water-based ink exhibiting a more preferable quick-drying property. It is expected that

[Production method of dispersible colorant]
The dispersible color material in which the chargeable resin pseudo fine particles are fixed to the color material used in the present invention can be obtained by a method using the following aqueous precipitation polymerization. FIG. 2 is a process diagram schematically showing a process flow of the manufacturing method. First, as shown in FIG. 2A, a dispersed aqueous solution (dispersion) in which the coloring material 1 is dispersed in the aqueous solution by the dispersant 3 is prepared. Next, the temperature of the dispersion prepared in FIG. 2A is raised while stirring, and the monomer component 4 is added to the dispersion together with, for example, the aqueous radical polymerization initiator 5 (see FIG. 2B). The added aqueous radical polymerization initiator generates radicals by cleaving when the temperature is raised. 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 It contributes to the reaction with water-soluble monomers.

  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 proceeds as described above, the oligomer 7 generated by the polymerization reaction of the monomer component becomes insoluble in water and precipitates from the aqueous phase (8 in the figure). Since they do not have stability, they are united to form the chargeable resin pseudo fine particles 2. Further, the chargeable resin pseudo fine particles 2 cause hetero-aggregation with the hydrophobic surface of the color material 1 in the dispersed aqueous solution as a nucleus, and the resin component constituting the color material surface and the charge resin pseudo fine particles 2 is caused by hydrophobic interaction. Adsorbs strongly. At this time, the polymerization reaction continues to proceed inside the chargeable resin pseudo fine particles 2, and changes to a more energy-stable form while increasing the adsorption point with the color material 1. At the same time, since the physical cross-linking is highly formed inside the chargeable resin pseudo fine particles, the form that adsorbs most stably to the colorant 1 is fixed and is in a fixed state. On the other hand, the coloring material 1 is stabilized by fixing a plurality of chargeable resin pseudo fine particles 2 and becomes a dispersible coloring material 6 used in the present invention. (See FIG. 2 (d) and FIG. 3).

  FIG. 4 shows a schematic view of the chargeable resin pseudo fine particles 2 on the fixing interface side with the color material 1. The charged resin pseudo fine particles 2 which are aggregates of resin components are distributed in the local surface energy because the hydrophilic monomer unit 9-1, the hydrophobic monomer unit 9-2 and the like are arbitrarily distributed. There are an infinite number of adsorption points 10 that coincide with the surface energy of the coloring material 1.

  FIG. 5 shows an enlarged schematic view of the fixing interface between the chargeable resin pseudo fine particles and the color material. The interface 11 of the chargeable resin pseudo fine particles is colored while adsorbing the adsorption point 10 shown in FIG. It takes a form corresponding to the surface shape of the material 1 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 colorant 1 is achieved by fixing the adsorption in a stabilized form. Through the above process, the dispersible colorant 6 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. By the electrostatic repulsive force acting on each other, the chargeable resin pseudo fine particles 2 are scattered and fixed to the color material 1 to be in the preferred form described above. On the other hand, the self-dispersion type pigment represented by the above-mentioned Patent Document 1 in which a hydrophilic group is directly modified has a pigment peeling phenomenon as schematically shown in FIG. It is done.

  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.

(Radically polymerizable monomer)
Since the radical polymerizable monomer used in the above-mentioned polymerization becomes a component constituting the chargeable resin pseudo fine particles, it may be appropriately selected depending on the characteristics of the dispersible color material to be obtained. In the production method of the present invention, any conventionally known radically polymerizable monomer or a radically polymerizable monomer newly developed for the present invention can be used. Examples of the monomer having a radically polymerizable unsaturated bond preferably used in the present invention (hereinafter referred to as a radically polymerizable monomer or simply a monomer) include the following. Classified as hydrophobic monomers, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylate-n-propyl, acrylate-n-butyl, acrylate-t-butyl, benzyl acrylate, methyl methacrylate (Meth) acrylic acid esters such as ethyl methacrylate, isopropyl methacrylate, methacrylate-n-propyl, methacrylate-n-butyl, isobutyl methacrylate, tert-butyl methacrylate, tridecyl methacrylate, benzyl methacrylate, etc. Styrene monomers such as styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-tert-butyl styrene, etc .; itaconic acid esters such as benzyl itaconate; dimethyl maleate, etc. Such as Esters; fumaric acid such as fumaric acid esters such as dimethyl acrylonitrile, methacrylonitrile, vinyl acetate, and the like.

  Examples of the monomer having an anionic group include monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid, fumaric acid, and the like. A monomer having a sulfonic acid group such as a salt, styrene sulfonic acid, sulfonic acid-2-propylacrylamide, acrylic acid-2-ethyl sulfonate, methacrylic acid-2-ethyl sulfonate, butyl acrylamide sulfonic acid, and the like; And monomers having a phosphonic acid group such as ethyl methacrylate-2-phosphonate and ethyl acrylate-2-phosphonate. Among these, it is particularly preferable to use acrylic acid and methacrylic acid.

  Examples of the monomer having a cationic group include a monomer having a primary amino group such as aminoethyl acrylate, aminopropyl acrylate, methacrylic acid amide, aminoethyl methacrylate, aminopropyl methacrylate, and the like. Second, such as methylaminoethyl, methylaminopropyl acrylate, ethylaminoethyl acrylate, ethylaminopropyl acrylate, methylaminoethyl methacrylate, methylaminopropyl methacrylate, ethylaminoethyl methacrylate, ethylaminopropyl methacrylate, etc. Monomers having secondary amino groups, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminopropyl acrylate, diethylaminopropyl acrylate, dimethylamino methacrylate Monomer having a tertiary amino group such as diethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, diethylaminopropyl methacrylate, dimethylaminoethyl methyl chloride salt, dimethylaminoethyl methyl methacrylate salt, dimethyl acrylate Examples thereof include monomers having a quaternary ammonium group such as aminoethylbenzyl chloride salt and dimethylaminoethylbenzyl chloride methacrylate, and various vinylimidazoles.

  Further, as the nonionic hydrophilic monomer, specifically, monomers having a radically polymerizable unsaturated bond and a hydroxyl group exhibiting strong hydrophilicity in the structure apply to this, for example, (meth) acrylic Hydroxyethyl acid, hydroxylpropyl (meth) acrylate, etc. are classified into this. In addition, various known or novel oligomers and macromonomers can be used without limitation.

  Furthermore, it is also a preferable aspect to use a crosslinkable monomer. For example, divinylbenzene, allyl (meth) acrylate, methylene bisacrylamide and the like can be used, and other known or novel various crosslinking monomers can also be used.

[Ink composition]
The recording ink (A) according to the present invention is characterized by including the dispersible colorant described above, but other components such as an aqueous medium and additives constituting the aqueous ink are conventionally used for inkjet inks. Any of those used in the above can be used. By ink-jet recording the recording ink (A) on a recording medium, as described above, an image having excellent quick drying properties can be obtained from the structural characteristics of the dispersible colorant.

  When the colorant is a pigment, the content of the dispersible colorant in the recording ink (A) is generally 0.1% by mass to 20% by mass with respect to the ink. Preferably, it is 0.3 mass% or more and 15 mass% or less. The aqueous medium is preferably a mixed medium containing water and, if necessary, an appropriate water-soluble organic solvent. Further, a penetrant for helping penetrability into the recording medium, an antiseptic, an antifungal agent, or the like may be included as an additive.

<Liquid composition (B)>
As described above, the recording ink (A) according to the present invention having the above-described configuration is used in combination with the liquid composition (B) containing the resin component described below, so that the formed image can be quickly dried. In addition, an excellent image having glossiness and high image density is obtained. The liquid composition (B) is sufficient if it contains at least a resin component, and it is not necessary to include a coloring material, and it is colorless without affecting the color tone of the recorded image formed by the recording ink (A). Or it is preferable that it is a pale color thing. Depending on the recording medium to be used, a coloring material may be added to give a light color. Further, as the other components constituting the liquid composition (B), any of ordinary aqueous media and additives used in ink jet recording inks can be used.

[Resin component]
The resin component necessary for the liquid composition (B) may be in a solution state, in a dispersed state, or in any form, that is, both a water-soluble polymer (resin) and an emulsion. Can be used. As the water-soluble polymer, any resin component such as any commonly used natural or synthetic polymer, or a polymer newly developed for the present invention can be used without limitation. Examples of resin components that can be used include acrylic resins, styrene / acrylic resins, polyester resins, amino resins, polyurethane resins, polyurea resins, polysaccharides, and polypeptides. In particular, from the viewpoint that it can be generally used and the functional design of the polymer can be easily performed, a polymer of a monomer component having the following radical polymerizable unsaturated bond, such as an acrylic resin or a styrene / acrylic resin, or these Copolymers with other monomers can be preferably used.

  As the monomer having a radical polymerizable unsaturated bond preferably used in the above, the same radical polymerizable monomer as exemplified in the description of the method for producing the chargeable resin pseudo fine particles can be used.

  As the resin component constituting the liquid composition (B) used in the present invention, any of nonionic, anionic and cationic resins can be used. Among these, a water-soluble polymer having chargeability opposite to that of the color material contained in the recording ink (A) according to the present invention is preferably used. By doing so, the electrostatic action causes the water-soluble resin to be present in the vicinity of the color material constituting the print image formed by the ink (A), and the uneven shape of the print image is As a result of further relaxation, the glossiness of the image is further improved. For example, when the color material contained in the recording ink (A) has an anionic group, a water-soluble polymer having a cationic group such as polyethyleneimine is used as a resin component constituting the liquid composition (B). It is preferable to use it. Below, the water-soluble polymer which can be used as a resin component which comprises the liquid composition (B) used by this invention is demonstrated.

  Examples of the water-soluble polymer (resin) having an anionic property include monomers having a carboxyl group such as (meth) acrylic acid, crotonic acid, itaconic acid, fumaric acid, styrene sulfonic acid, acrylic acid-2-ethyl sulfonate, methacrylic acid. Monomers having a sulfonic acid group such as ethyl 2-sulfonic acid, butylacrylamide sulfonic acid and the like, and salts thereof, phosphonic acid groups such as ethyl methacrylate-2-phosphonate, ethyl acrylate-2-phosphonate, etc. For example, a copolymer obtained by using a plurality of these monomers, a copolymer obtained by using any of the above monomers and another monomer, and the like.

  The anionic water-soluble polymer used in the liquid composition (B) preferably has an acid value of 100 to 300. When the water-soluble polymer is contained in the ink, it is usually used after neutralizing with a neutralizing agent. Although it does not specifically limit as a neutralizing agent used in this case, Usually, amines, such as alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, triethanolamine, diethanolamine, monoethanolamine, and triethylamine Is used.

  Examples of the water-soluble polymer (resin) having a cationic property include polymers and copolymers using at least one monomer having an amino group exemplified in the synthesis of the above-described chargeable resin pseudo fine particles, polyethyleneimine, etc. Amino resins, water-soluble urethane resins, and the like are used. As the cationic water-soluble polymer used in the liquid composition (B), those having an amine value of 50 to 100 are preferable. When the above water-soluble resin having cationic property is contained in the ink, it is usually used after neutralizing with a neutralizing agent. Although it does not specifically limit as a neutralizing agent used in this case, Organic acids, such as mineral acids, such as hydrochloric acid, and an acetic acid and propionic acid, etc. are mentioned.

  Further, as the water-soluble polymer (resin) having nonionic property, a polymer or copolymer containing a nonionic monomer exemplified in the description of the recording ink (A) such as ethylene oxide-modified (meth) acrylic ester. And polyvinyl alcohol. In addition, various known or novel oligomers and macromonomers can be used without limitation.

  Examples of emulsions that can be used as the resin component constituting the liquid composition (B) used in the present invention include acrylic resin emulsions, vinyl chloride emulsions, vinyl acetate emulsions, epoxy resin emulsions, amino resin emulsions, etc. A general thing can be used. Of course, any resin component such as an emulsion newly developed for the present invention can be used without limitation. It is preferable to use an emulsion having an average particle size of 200 nm or less. In this case, if the average particle diameter exceeds 200 nm, the glossiness and image density of the image may be lowered when an image is formed in combination with the recording ink (A), which is not preferable.

  Although the density | concentration of the above resin components in a liquid composition (B) is not specifically limited, Usually, it is used in 2 mass%-10 mass%. Furthermore, as the component constituting the other liquid composition (B), any of aqueous media and additives conventionally used in ink jet inks can be used. The aqueous medium is preferably a mixed medium containing water and, if necessary, an appropriate water-soluble organic solvent. Further, a penetrant for helping penetrability into the recording medium, an antiseptic, an antifungal agent, or the like may be included as an additive.

  The liquid composition (B) having the above-described structure is recorded on the recording portion (recorded image) by the recording ink (A) according to the present invention. The aqueous medium (ink solvent) of the composition (B) is rapidly absorbed into the recording medium. This is because the recording portion is formed of a dispersible color material contained in the recording ink (A). As described in the description of the recording ink (A), the dispersible color material is used. Is presumed that the ink solvent in the liquid composition (B) permeated quickly due to the capillary phenomenon from the morphological feature that the resin component is agglomerated in a state of aggregation in the resin component. .

<Recorded image>
The ink jet recording image according to the present invention is formed on a recording medium by an ink jet recording apparatus as described later using the recording ink (A) and the liquid composition (B) having the structure described above. Examples of the recording medium used in the present invention include plain paper and various recording media developed for ink-jet recording, and good results are obtained particularly for glossy paper.

<Image recording method and recording apparatus>
The ink set formed by combining the recording ink (A) and the liquid composition (B) according to the present invention is favorably used for an inkjet discharge type head. It is also effective as an ink tank in which these inks are stored or as ink for filling the ink tank. In particular, the ink set having the above configuration provides excellent effects in a bubble jet (registered trademark) recording head and recording apparatus, among inkjet recording methods.

  As for typical configurations and principles of these recording apparatuses, for example, the basic principles disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are used. What to do is preferred. 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 is 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 using the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate 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 recovery means for the recording head, preliminary auxiliary means, etc. provided as the configuration of the recording apparatus to be applied, because the effects of the present invention can be further stabilized. . Specific examples thereof include a capping unit for the recording head, a cleaning unit, a pressure or suction unit, an electrothermal converter, a heating element different from this, or a preheating unit using a combination thereof, This is a preliminary ejection mode in which ejection different from recording is performed.

  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]
<Preparation of recording ink (A)>
A recording ink 1 according to Example 1 was prepared in the following manner. First, a mixed liquid composed of 10 parts of a phthalocyanine pigment (PB15: 3), 6 parts of glycerin, 10 parts of a styrene-acrylic acid resin dispersant, and 74 parts of water was subjected to 1,500 rpm in a sand mill manufactured by Kanada Rika Kogyo Co., Ltd. Dispersion was carried out for 5 hours 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%. 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.

  Next, 100 parts of the pigment dispersion 1 obtained above was heated to 70 ° C. under a nitrogen atmosphere, and the following liquid was gradually added dropwise while stirring with a motor to perform polymerization for 5 hours. . The liquid used consists of 5.5 parts of styrene, 0.5 part of acrylic acid, 0.12 part of potassium hydroxide, 0.05 part of potassium persulfate and 20 parts of water. Next, the dispersion obtained by polymerization was diluted 10 times with water, and centrifuged at 5,000 rpm for 10 minutes to remove aggregated components not fixed to the coloring material. Then, the dispersible color material 1 which is a sediment was obtained by further centrifuging at 12,500 rpm for 2 hours.

  The dispersible colorant 1 obtained above was dispersed in water, centrifuged at 12,000 rpm for 60 minutes, and the precipitate redispersed in water was dried. When the dried product (dispersible colorant 1) was observed with a scanning electron microscope JSM-6700 (manufactured by JEOL Hi-Tech Co., Ltd.) at a magnification of 50,000 times, the charged resin pseudo fine particles were fixed on the surface of the pigment particles. A state of being observed was observed.

  The following components are mixed so that the dispersible colorant 1 obtained above has a concentration of 4% in the ink, and further filtered under pressure with a membrane filter having a pore size of 2.5 microns. Recording ink (A1). The total amount of ink was adjusted with water so as to be 100 parts. The same applies to the subsequent inks.

・ Dispersible colorant 1 4 parts ・ Glycerin 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 7 parts ・ Acetylenol EH (trade name: manufactured by Kawaken Fine Chemicals Co., Ltd.) 0.2 part ・ Ion-exchanged water remaining

<Preparation of liquid composition (B)>
The liquid composition (B) was mixed with the following components, and further filtered under pressure with a membrane filter having a pore size of 2.5 microns to obtain a liquid composition (B1) used in this example. In addition, it adjusted with water so that the whole quantity of a liquid composition might be 100 parts. The same applies to the subsequent liquid compositions.

・ Styrene-acrylic resin (Mw = 10,000, acid value 140, equivalent neutralization with calcium hydroxide) 4 parts ・ Glycerin 7 parts ・ Diethylene glycol 5 parts ・ Trimethylolpropane 7 parts ・ Acetylenol EH (trade name: Kawa Ken Fine Chemical Co., Ltd.) 1 part, remaining ion-exchanged water

<Evaluation method and evaluation result of recording ink>
The recording ink (A1) obtained by the method described above and the liquid composition (B1) are combined to form a set, and an image is formed by the following method using the recording ink (A1). Was evaluated. That is, with the ink jet recording apparatus described below, the recording ink (A1) was printed on a glossy paper (Pro Photo Paper manufactured by Canon Inc.) on a 2 cm square using the ink jet recording apparatus. Immediately after printing, the liquid composition (B1) was solid-printed on the solid printing portion with an ink jet recording apparatus, and the obtained image was evaluated. BJS600 (trade name: manufactured by Canon Inc.) was used for the ink jet recording apparatus. About the printed matter obtained by printing above, the optical density, glossiness, and quick drying property were evaluated by the following methods and standards, and the results are shown in Table 1.

<Optical density (OD)>
The optical density of the solid print portion formed on the glossy paper was measured with a reflection densitometer Macbeth RD-918 (manufactured by Macbeth), and the value is shown in Table 1.

<Glossiness>
About the solid printing part formed in the glossy paper, the glossiness with respect to 20 degrees of incident light was measured, and the value was shown in Table 1. For the measurement of glossiness, a micro haze meter (Bikku Gardner) was used.

<Quick-drying>
The solid print portion formed on the glossy paper was rubbed with a finger 1 minute after the completion of printing, and the stain on the print portion was evaluated according to the following criteria. The obtained results are shown in Table 1.
A: There is almost no stain on the blank paper portion.
B: The blank paper portion is slightly stained, but there is no problem in character recognition.
C: Disturbance of printing occurs and the blank paper portion is clearly stained.

[Example 2]
In the preparation of the liquid composition (B1), a liquid was prepared in the same manner as in Example 1, except that the same amount of polyethyleneimine (amine value 150, Mw 10,000) was used instead of the styrene-acrylic resin. A composition (B2) was obtained. In the same manner as in Example 1 except that a set comprising the obtained liquid composition (B2) and the ink (A1) used in Example 1 was used, an image was formed by the set and evaluated. The results are shown in Table 1.

[Example 3]
In the preparation of the liquid composition (B1), an emulsion (manufactured by Johnson Polymer Co., Ltd., trade name: Jonkrill 7001, average particle size 80 nm) is used instead of the styrene-acrylic acid resin which is a water-soluble resin, and the resin content is the same. A liquid composition (B3) was obtained in the same manner as in Example 1 except that the amount was adjusted. Image formation by the set was evaluated in the same manner as in Example 1 except that the set comprising the obtained liquid composition (B3) and the ink (A1) used in Example 1 was used. The obtained results are shown in Table 1.

[Comparative Example 1]
The same components as in Example 1 were mixed so that the pigment dispersion 1 in Example 1 had a concentration of 4% in the ink, and further filtered under pressure with a membrane filter having a pore size of 2.5 microns. The recording ink of this comparative example was used. Then, the image formation by the set was evaluated in the same manner as in Example 1 except that the obtained recording ink and the liquid composition (B1) used in Example 1 were used as a set. The obtained results are shown in Table 1.

  First, the recording ink (A) is printed to form an image, and then the liquid composition (B) is printed second, so that not only quick drying but also image density (optical density) and glossiness are excellent. Images can be obtained.

It is a schematic diagram for demonstrating the basic structure in which the chargeable resin pseudo fine particles are fixed to the color material in the dispersible color material used in the present invention. It is a schematic diagram for demonstrating the typical process in the manufacturing method of the dispersible color material used by this invention. It is a schematic diagram for demonstrating the production | generation of the chargeable resin pseudo fine particle in the manufacturing method of the dispersible color material used by this invention, and the adhering process to a color material. It is the schematic diagram which expanded the chargeable resin pseudo fine particle which comprises the dispersible color material used by this invention from the interface side fixed to a color material. It is the schematic diagram which expanded the interface which the chargeable resin pseudo fine particles and color material which comprise the dispersible color material used by this invention adhere. It is a figure which illustrates typically the peeling phenomenon of the pigment in the self-dispersion type pigment which directly modified the hydrophilic group to the pigment. FIG. 6 is a schematic diagram illustrating an aggregation state of a dispersible color material on a recording medium.

Explanation of symbols

1: Color material 2: Charged resin pseudo fine particles 3: Dispersion resin 4: Monomer 5: Polymerization initiator aqueous solution 6: Dispersible color material 7: Oligomer formed by polymerization of monomer 8: Precipitation in which oligomer is insolubilized in water Product 9-1: Hydrophilic monomer unit portion 9-2 in the charged resin pseudo fine particle 9-2: Hydrophobic monomer unit portion 10 in the charge resin pseudo fine particle 10: Bonding site with the coloring material 11: Color of the charge resin pseudo fine particle Interface portion 12 with material: hydrophilic group 14 directly modified with color material 14: recording medium

Claims (9)

  A recording ink (A) for forming a recording image used in an ink recording method for applying a liquid composition (B) containing a resin component after forming a recording image, the ink (A) comprising a colorant, A recording ink comprising a dispersible color material which is smaller than the color material and is composed of chargeable resin pseudo fine particles fixed to the color material.   The recording ink according to claim 1, wherein the chargeable resin pseudo fine particles have an anionic property.   The recording ink according to claim 1, wherein the chargeable resin pseudo fine particles have a cationic property.   A step (I) of applying a recording ink (A) having a dispersible color material comprising a color material and a chargeable resin pseudo fine particle smaller than the color material and fixed to the color material on a recording medium; And at least a step (II) of applying a liquid composition (B) containing a resin component on a recording image of the recording ink (A), and performing the step (II) following the step (I). A recording method characterized by the above.   The recording method according to claim 4, wherein the resin component contained in the liquid composition (B) is a cationic water-soluble resin.   The recording method according to claim 4, wherein the resin component contained in the liquid composition (B) is an anionic water-soluble resin.   The recording method according to claim 4, wherein the resin component contained in the liquid composition (B) is an emulsion.   An ink jet recording apparatus comprising the recording ink according to claim 1.   An inkjet recording image formed by an inkjet recording apparatus using the recording method according to claim 5.

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