JP2002332436A - Inkset, method for forming colored part on medium to be printed and ink-jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid composition capable of giving high-quality, ink-jet printed matters of good color developability, an inkset, to provide a method for forming colored part(s) on a medium to be printed, and an ink-jet printer. SOLUTION: This inkset is a water-based liquid composition containing microparticles in a dispersed state with the surface charged antipolarly to the inkset. The method for forming colored part(s) on a medium to be printed and the ink-jet printer are provided, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for obtaining an image having excellent color developability and color uniformity in forming a color image. The present invention relates to a method for forming a colored portion on a recording medium and an ink jet recording apparatus.

[0002]

2. Description of the Related Art In an ink jet recording method, recording is performed by flying ink and attaching the ink to a recording medium such as paper. For example, Japanese Patent Publication No. 61-59911, Japanese Patent Publication No. 61-59912 and Japanese Patent Publication No. 61-5
According to the ink jet recording method disclosed in Japanese Patent Application No. 9914, in which an electrothermal converter is used as a discharge energy supply unit and droplets are discharged by applying thermal energy to ink to generate bubbles. , A high-density multi-orifice can be easily realized, and a high-resolution and high-quality image can be recorded at a high speed.

The ink used in the conventional ink jet recording method is mainly composed of water, and water-soluble high-boiling solvents such as glycol for the purpose of preventing drying of the ink in the nozzles and clogging of the nozzles. Is generally contained.

[0004] Therefore, when recording is performed on a recording medium using such an ink, sufficient fixability cannot be obtained, or unevenness of the filler or sizing agent on the surface of the recording paper as the recording medium. In some cases, a problem such as generation of a non-uniform image which is estimated to be due to an uneven distribution may occur.

On the other hand, in recent years, there has been a strong demand for ink-jet recorded images to have the same level of image quality as silver halide photographs. In addition, technical requirements for improving the color uniformity of a recorded image have become extremely high.

Under these circumstances, various proposals have been made so far in order to stabilize the ink jet recording method and to improve the quality of a recorded image by the ink jet recording method. As one of the proposals for a recording medium, a method of applying a filler or a sizing agent on the surface of a base paper of the recording medium has been proposed. For example, there is disclosed a technique in which porous fine particles for adsorbing a coloring material are applied to a base paper as a filler, and an ink receiving layer is formed using the porous fine particles. As recording media using these techniques, inkjet coated paper and the like are on the market.

Under these circumstances, various proposals have been made so far in order to stabilize the ink jet recording method and to improve the quality of a recorded image by the ink jet recording method. Some of the typical ones are summarized below. (1) a method of internally adding a volatile solvent or a penetrating solvent to the ink;
As a means for accelerating the fixability of the ink to the recording medium, Japanese Patent Application Laid-Open No. 55-65269 discloses a method of adding a compound such as a surfactant to the ink to enhance the permeability. Japanese Patent Application Laid-Open No. 55-66976 discloses the use of an ink mainly composed of a volatile solvent. (2) A method of mixing a liquid composition that reacts with the ink with the ink on a recording medium; an ink for forming a recorded image for the purpose of improving image density, improving water resistance, and suppressing bleeding Prior to or after jetting, a method of applying a liquid composition for improving an image on a recording medium has been proposed.

For example, Japanese Patent Application Laid-Open No. 63-60783 discloses a method in which a liquid composition containing a basic polymer is applied to a recording medium and then recorded with an ink containing an anionic dye. JP-A-63-226
No. 81 discloses a recording method in which a first liquid composition containing a reactive species and a second liquid composition containing a compound which reacts with the reactive species are mixed on a recording medium. Further, JP-A-63-2999971 discloses that
A method is disclosed in which a liquid composition containing an organic compound having two or more cationic groups per molecule is applied onto a recording medium, and then recording is performed with an ink containing an anionic dye. JP-A-64-9279 discloses a method in which an acidic liquid composition containing succinic acid or the like is applied onto a recording medium, and recording is performed with an ink containing an anionic dye.

Further, Japanese Patent Application Laid-Open No. 64-63185 discloses a method in which a liquid composition for insolubilizing a dye is applied to paper prior to application of ink.
Further, Japanese Patent Application Laid-Open No. Hei 8-224595 discloses a method of using a liquid composition containing a cationic substance having a different molecular weight distribution region together with an ink containing an anionic compound. A method is disclosed in which a liquid composition containing a cationic substance and finely ground cellulose is used together with an ink. Is obtained. Japanese Patent Application Laid-Open No. 55-150396 discloses a method of recording a recording medium with a dye ink and then applying a water-resistant agent that forms a lake with the dye.
It has been proposed to impart water resistance to a recorded image.

(3) A method of mixing the ink and the fine particle-containing liquid composition on a recording medium;
Japanese Patent Application Laid-Open No. 6-92010 discloses a method in which a colorless liquid containing colorless fine particles made of an inorganic substance is applied onto a recording medium, and then a non-aqueous recording liquid is attached thereto. After applying a solution containing, or a solution containing fine particles and a binder polymer on a recording medium, a pigment,
A method for adhering an ink containing a water-soluble resin, a water-soluble solvent, and water is disclosed, and it is described that an image having good print quality and color development can be obtained regardless of the type of paper.

(Background Art) The present inventors have conducted various studies on the above-described various types of ink jet recording techniques. As a result, although excellent effects can be confirmed for each technical problem, in exchange for that, other effects were obtained. It has been found that the ink jet recording characteristics may be deteriorated. For example, a recording medium (hereinafter referred to as coated paper) obtained by applying a filler or a sizing agent on the surface of the base paper of the recording medium described above.
Is recognized as a technology capable of forming high-quality images.

In general, it is known that in order to obtain a high chroma image, it is necessary to leave the color material in a monomolecular state on the surface of the recording medium without agglomeration. The porous fine particles of the coated paper have such a function. However,
In order to obtain high image density and image saturation, it is indispensable to form a thick ink receiving layer that covers the base paper with a large amount of porous fine particles for the coloring material in the given ink. There is a problem that the texture of the base paper is lost. The present inventors have speculated that the reason why the ink receiving layer is necessary to lose the texture of the base paper is that the coloring material is not efficiently adsorbed on the porous fine particles.

The following description is based on the assumption that a coated paper has one ink receiving layer. FIG. 9 schematically shows a cross section near the surface of the coated paper. In the figure, 90
Reference numeral 1 denotes a base paper, and 903 denotes an ink receiving layer. In general, the ink receiving layer 903 has porous fine particles 905 and an adhesive 907 for fixing them. When the ink is applied, the ink penetrates the gaps between the porous fine particles 905 by capillary action, and forms an ink penetrating portion 909. As shown in the figure, since the porous fine particles in the ink receiving layer have locally different densities, the manner of permeation of the ink by the capillary phenomenon differs depending on the location. Therefore, during the ink permeation process, the coloring material cannot uniformly contact the surface of the porous fine particles, and the coloring material is not efficiently adsorbed on the porous fine particles.

Further, there are portions where the penetration of ink is inhibited by the adhesive 907, and there are portions where the ink cannot penetrate in the ink receiving layer 903, and portions which do not contribute to color development occur. That is, in the conventional coated paper, the coloring material cannot be efficiently adsorbed in a monomolecular state with respect to the amount of the porous fine particles for the above-described reason,
As a result, in order to obtain a high quality image, a large amount of porous fine particles is required, which impairs the texture of the base paper.

Further, by adopting the technique (1),
Although the fixability of the ink to the recording medium is improved, the image density may decrease, and the color reproduction range important for recording on plain paper or recording a color image may decrease.
Further, according to the technique (2), the color material in the ink can be retained on the surface of the recording medium, so that a recorded image having a high image density can be obtained. However, due to the aggregation of the color material on the surface of the recording medium, a sufficient color reproduction range and saturation may not be obtained in some cases.

In the prior art described in the above (3), although the surface condition of the recording medium is modified by applying a solution containing fine particles, a high-definition image at the same level as coated paper is obtained. I couldn't. In particular, the non-aqueous recording liquid is limited in the selectivity of the coloring material, the method of applying the recording liquid, and the like. As described above, since the conventional methods still have problems, a new ink jet recording technology needs to be developed for higher quality ink jet recorded images required in recent years. The present inventors have realized that the above is true. The present invention has been made based on the new findings described above.

On the basis of the above-described new findings, the present inventors have used fine particles having a function of adsorbing a coloring material, and in order to efficiently adsorb or bond the coloring material to the fine particles, By dispersing and using the ink in a liquid state together with the ink, it becomes possible to cause the color material and the fine particles to react in a liquid-liquid state, and as a result, it is possible to improve the density and saturation of an image with high reliability. This led to the present invention.

[0018]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink capable of obtaining a high-quality ink jet recorded image having a wider color reproduction range, excellent bleed control and excellent color uniformity. Provide a set,
An object of the present invention is to provide an ink set which is excellent in reliability in printing, specifically, storage stability and ejection stability from a recording head.

Another object of the present invention is to provide a wider color reproduction range, excellent suppression of bleeding and excellent color uniformity, less solid streaks, good scratch resistance,
An object of the present invention is to provide a method for forming a colored portion on a recording medium which is capable of forming an ink jet recorded image having excellent weather resistance even on plain paper and having excellent reliability in printing.

Another object of the present invention is to provide a wider color reproduction range, excellent bleed control and excellent color uniformity.
An ink set and an ink jet recording apparatus, which can form an ink jet recording image excellent in scratch resistance and weather resistance in which the occurrence of uneven streaks in a solid portion is suppressed to a favorable state, and also has excellent reliability in printing. To provide. Further, another object of the present invention is to use a specific pigment in the present invention in a colored ink, as compared with the case of using other pigments, to reduce the amount of liquid composition to be applied to a recorded image. The purpose is to reduce cockling.

[0021]

The above objects can be achieved by the present invention described below. That is, the present invention relates to a colored ink set including at least a black ink, a cyan ink, a magenta ink, and a yellow ink each containing a pigment as a coloring material, and fine particles having a surface charged to the opposite polarity to the colored ink set. An ink set comprising a liquid composition contained in a dispersed state, wherein black ink is carbon black, and cyan ink is C.I. I. Pigment Blue 15: 3 or 15:
4. Magenta ink is C.I. I. Pigment Red 12
2. The yellow ink is C.I. I. Pigment Yellow 7
4, 128, 147, 150, 154, 180 and 18
5. An ink set comprising at least one selected from No. 5 is provided.

In the present invention, the black ink is carbon black, and the cyan ink is C.I. I. Pigment Blue 15: 3, magenta ink is C.I. I. Pigment Red 122 and yellow ink are C.I. I. Pigment Yellow 74; the black ink is carbon black, the cyan ink is C.I. I. Pigment Blue 15: 3, magenta ink is C.I. I. Pigment Red 122 and yellow ink are C.I. I. The above ink set including CI Pigment Yellow 128; black ink;
The present invention provides the above ink set, wherein the colored ink including the cyan ink, the magenta ink, and the yellow ink is anionic, and the liquid composition has a zeta potential of +5 to +90 mV.

Further, according to the present invention, the colored ink composed of black ink, cyan ink, magenta ink and yellow ink is anionic, the liquid composition further contains an acid, and the pH is adjusted to 2 to 7. The above ink set; a primary dissociation constant pKa in water of an acid of 5 or less; a black ink, a cyan ink,
The colored ink including the magenta ink and the yellow ink is cationic, and the zeta potential of the liquid composition is −
The above ink set, having a pH of 5 to -90 mV; the colored ink including the black ink, the cyan ink, the magenta ink, and the yellow ink is cationic, and the liquid composition further includes a base, and the pH is adjusted to 7 to 12. Above ink set; first-order dissociation constant p of base in water
The above-mentioned ink set in which Kb is 5 or less; the above-mentioned ink set in which the liquid composition contains fine particles having an average particle diameter in the range of 0.005 to 1 μm; The above-described ink set is provided.

The present invention also provides a method for forming a colored portion on a recording medium using the above-mentioned ink set, wherein (i)
Applying the colored ink to the recording medium, and (ii) applying the liquid composition containing the water-soluble polymer to the recording medium, wherein the liquid composition contains fine particles whose surface is charged in the opposite polarity to the ink in a dispersed state. The colored ink and the liquid composition are brought into contact with each other in a liquid state on the surface of the recording medium. A method for forming a colored portion on a recording medium, characterized in that the process (i) is performed after at least the process (ii) is performed; ) Is performed, and then the method of forming a colored portion, in which the step (ii) is performed, and the step (ii) is performed after the step (i) is performed, and then the step (i) is performed again. And a method for forming the above-mentioned colored portion.

Further, the present invention provides a method for applying a colored ink to a recording medium in the step (i) by an ink jet recording method in which the colored ink is ejected from an orifice according to a recording signal. Forming method;
The above-mentioned method for forming a colored portion, wherein the ink jet recording method is a method in which the ink is ejected from an orifice by applying thermal energy to the ink; the application of the liquid composition to the recording medium in the step (ii) is performed by applying the liquid The above-described method of forming a colored portion, which is performed by an inkjet recording method of discharging a composition from an orifice in accordance with a recording signal, and the inkjet recording method discharges the liquid composition from the orifice by applying thermal energy to the liquid composition. The present invention provides a method for forming the above-mentioned colored portion, which is a method for causing the colored portion to be formed.

According to the present invention, there is provided an ink storage section containing the colored ink, a first recording unit including an ink jet head for discharging the ink, and a liquid composition containing the liquid composition. An ink jet recording apparatus, comprising: a container, and a second recording unit including an ink jet head for discharging the liquid composition; an ink container containing the colored ink; A liquid composition storage section containing the liquid composition, and a colored ink stored in the ink storage section and a liquid composition stored in the liquid composition storage section for independently discharging the liquid composition. An ink jet recording apparatus comprising: an ink jet head; and the ink jet head ejecting liquid by applying thermal energy. Providing the ink jet recording apparatus is a thermal ink jet head for.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. (Explanation of mechanism) The reason why the above-mentioned excellent effects are exerted by the present invention is not clear, but the present inventors believe that it is due to the following reasons. First, the recording mechanism in the present invention will be described with reference to FIGS.
It will be described according to. Here, an aqueous black ink containing an anionic resin-dispersed carbon black is used as a coloring ink (hereinafter abbreviated as ink), and fine particles having a cationically charged surface are dispersed in a liquid composition at the same time. The case where the used liquid composition is used will be described.

Hereinafter, a recorded image according to the present invention will be described with reference to FIG. First, words are defined prior to explanation. In the present invention, the “monomolecular state” indicates that the coloring material substantially maintains a state of being dissolved or dispersed in the ink. At this time, even if the coloring material causes some aggregation, the coloring material is included in the “monomolecular state” as long as the saturation is not reduced. For example, in the case of a dye, since it is considered preferable to be a single molecule,
For convenience, the pigment is also referred to as “monomolecular state”.

FIG. 13 is a diagram schematically showing a state in which a coloring portion I of a recorded image according to the present invention is composed of a main image portion IM and a peripheral portion IS thereof. In FIG. 13, reference numeral 1301 denotes a recording medium, and 1302 denotes a gap generated between fibers of the recording medium. Also, 1303 is the color material 13
Numeral 05 schematically shows fine particles which are chemically adsorbed. As shown in FIG. 13, in the ink jet recorded image of the present invention, the main image portion IM is such that the color material 1305 is uniformly formed on the surface in a single molecule or a state close to a single molecule (hereinafter abbreviated as “single molecule state”). It is composed of adsorbed fine particles 1303 and an aggregate 1307 of fine particles that keep the colorant in a monomolecular state. Reference numeral 1309 denotes an aggregate of fine particles existing near the recording medium fibers in the main image area IM.

The main image area IM includes a process in which the fine particles 1303 are physically or chemically adsorbed on the recording medium fibers,
305 and fine particles 1303 are formed by a process of adsorbing in a liquid-liquid state. Therefore, even in a recording medium such as plain paper in which the ink easily sinks, the image density and saturation are high, and an image having a wide color reproduction range similar to that of coated paper can be formed even when the coloring material of the coloring material itself is not impaired. It becomes possible.

On the other hand, it is not adsorbed on the fine particle surface 1303,
The coloring material 1305 remaining in the ink is a recording medium 1301.
Penetrates both in the lateral direction and in the depth direction with respect to the ink, the ink forms a slight blur in the peripheral portion IS. As described above, since the coloring material remains near the surface of the recording medium 1301 and minute bleeding of the ink is formed in the peripheral portion, even in an image area where a large amount of ink is applied, such as a shadow portion or a solid portion, a white haze or Less color unevenness and excellent color uniformity. In addition, as shown in FIG. 13, when the recording medium 1301 has permeability of the ink or the liquid composition, the present embodiment relates to the penetration of the ink component or the liquid composition component into the recording medium. Is not necessarily hindered, but allows some penetration.

Further, when the liquid composition of the present invention is used, when a fine particle aggregate 1309 existing near the surface of the recording medium is formed, pores of a certain size are formed inside the aggregate. It is formed. The coloring material 1305 which was present alone in the ink described above penetrates into the pores of the fine particle aggregates 1309 when penetrating into the recording medium,
The coloring material can be adsorbed to the vicinity of the entrance of the pores or to the inner wall in an ideal monomolecular state, so that more coloring material can be left near the surface of the recording medium. This makes it possible to obtain a recorded image having even better coloring properties.

FIGS. 14 (1) to 14 (4) are schematic sectional views of a colored portion 1400 of one embodiment of a method for forming a colored portion on a recording medium according to the present invention, and schematic steps for explaining the forming process. FIG. 13, reference numeral 1401 denotes a portion mainly containing a reaction product of the ink and the liquid composition, for example, a reaction product of a coloring material and fine particles (hereinafter abbreviated as “reaction portion”). It is a corresponding part. 14
Reference numeral 02 denotes a portion (hereinafter, abbreviated as “ink outflow portion”) formed by the ink that has not substantially participated in the reaction with the liquid composition flowing out to the periphery of the reaction portion 1401, and is shown in FIG. Corresponds to the peripheral portion IS. Such coloring section 14
00 is formed, for example, as follows. Incidentally, reference numeral 1405 shown in the figure schematically represents a gap generated between the fibers of the recording medium.

First, the coloring material 1404 and the liquid composition 1406 having reactivity are applied as droplets to the recording medium 1403 (FIG. 14A). As a result, a liquid composition pool 1407 is formed. (FIG. 14 (2)). The pool 1
407, the fine particles 14 near the fiber surface of the recording medium.
09 is physically or chemically adsorbed on the fiber surface of the recording medium. At this time, it is considered that there is a case where the dispersion state becomes unstable and aggregates 1411 of fine particles are formed.
On the other hand, in the portion far from the fiber in the liquid pool 1407,
It is considered that the fine particles 1409 maintain the original dispersion state.

Next, the ink 1413 is applied as droplets to the recording medium 1403 (FIG. 14 (2)). As a result, first, at the interface between the ink 1413 and the liquid pool 1407, the coloring material 1404 is chemically adsorbed to the fine particles 1409. Since this reaction is a reaction between liquids (liquid-liquid reaction), the coloring material 1404 is considered to be uniformly adsorbed on the surface of the fine particles 1409 in a monomolecular state (FIG. 14 (3)-).
2). That is, it is presumed that the coloring materials do not agglomerate on the surface of the fine particles, or even if the agglomeration is slight. As a result, the coloring material 1 in a monomolecular state is
A large number of fine particles adsorbed by 404 are formed, and the coloring material can be left in a monomolecular state on the surface layer that most affects color development, so that a recorded image with high image density and high saturation can be formed. I do.

Next, the fine particles adsorbing the coloring material 1404 are considered to be aggregated by the fine particles because the dispersion state becomes unstable (FIG. 14 (3) -2). That is, the aggregate 1415 formed here also holds a monomolecular color material inside. The aggregate 1415 forms a recorded image with high image density and high chroma.

Further, a part of the unreacted coloring material 1404 diffuses in the liquid pool 1407 and is adsorbed on the surface of the unreacted fine particles 1409. As described above, since the reaction between the coloring material and the fine particles further proceeds inside the liquid reservoir 1407, an image having higher density and higher saturation is formed. The aggregate 1411 of fine particles formed on the fiber surface of the recording medium described above is considered to have a role of suppressing the penetration of the liquid phase of the liquid pool 1407 into the recording medium. For this reason, in the liquid pool 1407, it becomes possible to mix more of the fine particles 1409 and the coloring material 1404 in the liquid composition whose permeation is suppressed.
As a result, the probability of contact between the coloring material 1404 and the fine particles 1409 is increased, the reaction proceeds relatively uniformly and sufficiently, and a more uniform image having excellent image density and saturation is formed.

The liquid composition 1406 is applied to the recording medium 1.
403 (FIG. 14 (1)) or the liquid pool 14
07 when the ink 1413 is applied (see FIG. 14).
(2)) Dispersion of the fine particles 1409 becomes unstable due to a change in the dispersion medium in which the fine particles 1409 are dispersed, and there are some substances that cause aggregation between the fine particles 1409 before the coloring material 1404 is adsorbed. The change in the dispersion medium referred to here is a change generally observed when two or more different liquids are mixed, such as a pH of a liquid phase, a solid content concentration, a solvent composition, and a dissolved ion concentration. It is considered that when the liquid composition comes into contact with a recording medium or ink, these changes occur rapidly and in a complex manner, destroying the dispersion stability of the fine particles, and generating aggregates. . It is presumed that these aggregates have the effect of filling the voids between the fibers and the effect of leaving the fine particles adsorbing the coloring material more near the surface of the recording medium.

The aggregate formed in the liquid pool 1407 may be adsorbed on the recording medium,
Some can move (have fluidity) in the liquid phase,
In the case of those having fluidity, similar to the above-described reaction process between the coloring material and the fine particles, the coloring material is adsorbed in a monomolecular state on the surface of the fine particle aggregates to form a larger aggregate, which improves the coloring property. Are contributing. It is considered that when the liquid phase permeates along the fiber, it moves together with the liquid phase, fills voids, smoothes the surface of the recording medium, and contributes to the formation of a more uniform and high-density image.

It is clear from the results described below that a high color image can be obtained by the present invention. This is because, as described above, the coloring material is adsorbed to fine particles or fine particle aggregates in a monomolecular state. It is considered that this is because it remained near the surface of the recording medium in the state. The coloring material is adsorbed in a monomolecular state, and the fine particles remaining near the surface of the recording medium are fixed on the surface of the recording medium. This improves the fastness of the image such as scratch resistance and water resistance.

In the above description, the case where the liquid composition and the ink are applied to the recording medium in this order has been described. The order of applying the composition to the recording medium is not limited to this, and the order of applying the ink and then the liquid composition may be used. Further, as shown in FIG. 14 (2), at least a part of the fine particles in the liquid composition applied to the recording medium penetrates into the recording medium as the liquid medium penetrates into the recording medium. it seems to do.

On the other hand, as clearly shown in FIG. 14 (4), it can be sufficiently assumed that the coloring material is adsorbed or bonded to the previously permeated fine particles in a monomolecular state. Thus, it is considered that the fine particles in which the coloring material is adsorbed or bonded in a monomolecular state inside the recording medium also contributes to the improvement of the coloring property. Further, it is considered that the fixability is improved by the penetration of the liquid medium.

Further, by using the liquid composition of the present invention, when the fine particle aggregate 1411 existing near the surface of the recording medium is formed, pores of a certain size are formed inside the aggregate. Is formed. The coloring material 1404 that could not be completely absorbed by the fine particles 1409 in the liquid pool 1407 is
When penetrating into the inside of the recording medium, some penetrate into the fine particle aggregate 1411 through the pores together with the solvent component.

At this time, the coloring material 1305 is adsorbed near the entrance of the pores in the fine particle aggregates and on the inner wall of the pores, and only the solvent component permeates into the recording medium, so that the coloring material is increased. The fine particles can be efficiently adsorbed on the surface or inside of the aggregate 1411 and remain near the surface of the recording medium. Further, when the coloring material 1404 is a dye, the fine particle aggregate 14
Since the pore diameter of 11 is about 1 to several times the molecular size existing in the ink of the coloring material 1404, the coloring material 1404 adsorbed inside the pores is extremely unlikely to cause aggregation between the coloring materials. Thus, an ideal single molecule state can be formed. This greatly contributes to further improvement of the color developability, and a recorded image having a wider color reproduction range can be obtained.

Further, it is understood that the pore physical properties of the fine particle aggregates 1411 are affected not only by the fine particles contained in the liquid composition but also by the solvent composition and the like. It has been found that the pore volume in a specific pore radius region of the fine particle aggregate has a very high correlation with the image forming ability formed on the recording medium.

Further, in the present invention, when the coloring material is anionic, the coloring material is extremely efficiently applied to the surface of the cationic fine particles by reacting the fine particles and the coloring material in a liquid phase on the surface of the recording medium. Will be adsorbed.

Hereinafter, differences between the ideas of the present invention and the prior art will be described. In order to achieve the same level of colorant adsorption as in the present invention in ink-jet coated paper, a large amount of cationic porous fine particles is required, and it is essential to form a thick ink receiving layer that covers the base paper. For this reason, the coated paper leads to the result of impairing the texture of the base paper.However, since the amount of the fine particles constituting the liquid composition of the present invention can be reduced, the recorded image and the unprinted area can be reduced without impairing the texture of the recording medium. Thus, an image can be formed without a sense of discomfort in texture.

The amount of the color material remaining on the surface of the recording medium is not sufficient as in the technique 1), or the amount of the color material remaining on the surface of the recording medium is insufficient as in the technique 2). However, in the present invention, the coloring material adsorbed on the surface of the fine particles can be left on the surface of the recording medium together with the fine particles, and the coloring material is in a monomolecular state. , It is possible to obtain a high color image.

Further, the present invention relates to the above-mentioned prior art (3) in that an image is formed by applying a liquid composition containing fine particles and ink to the surface of a recording medium.
At first glance, it seems to be similar to the method of externally adding the fine particle-containing liquid composition to the ink described above. However, in the present invention, as described above, the liquid composition and the coloring material are positively reacted with each other, and the fine particles in the liquid composition are used as a means for suppressing the aggregation (rake) of the coloring material. In the conventional technique described in (3), the purpose of applying the solution containing the fine particles is to modify the surface state of the recording medium, and the chemical reaction between the fine particles having different polarities and the coloring material in the ink is performed. Is not disclosed at all. The difference in quality between the recorded image according to these recording techniques and the recorded image obtained by the present invention, which is presumed to be based on the difference in the mechanism, was obvious.

Hereinafter, the liquid composition and the ink which characterize the present invention will be described in detail. First, the definition of the cationic ink or the anionic ink in this specification will be described. It is well known in the art that when referring to the ionic properties of an ink, the ink itself is uncharged and neutral in itself. The term “anionic ink or cationic ink” as used herein means a component in the ink, for example, a colorant has an anionic group or a cationic group, and in the ink, these groups are anionic or cationic. It refers to ink that has been adjusted to act as a base. The meaning of the anionic or cationic liquid composition is the same as described above.

<Liquid Composition> The liquid composition according to the present invention will be described below. [Measurement Method of Liquid Composition] In the present invention, the pore volume in a specific pore radius region of a fine particle aggregate obtained from a liquid composition containing at least fine particles and a solvent is measured according to the following method. First, in measuring these pore properties, the liquid composition is pre-treated in the following procedure. (1) The liquid composition is dried at 120 ° C. for 10 hours in an air atmosphere to evaporate almost the solvent and then dried. (2) The dried product is heated from 120 ° C. to 700 ° C. in one hour, and then baked at 700 ° C. for three hours. (3) After firing, the temperature of the fired product is gradually returned to room temperature, and the fired product is powdered. Here, the reason for performing the above pretreatment is to form fine particles aggregates from the liquid composition by drying, completely remove the solvent component by firing, and empty the pores inside the aggregates to form voids. It is.

As a method for measuring the pore radius and the pore volume used in the present invention, a nitrogen adsorption / desorption method can be suitably used. The size of the pores of the fine particle aggregate to be measured in the present invention is a pore volume in a region having a pore radius of 3 nm to 30 nm. It is not clear why the pore volume in this region is highly correlated to the image forming ability, but to speculate,
In the region smaller than the pore radius, the penetration of the coloring material and the solvent component into the inside of the fine particle aggregate is significantly reduced, the adsorption of the coloring material due to the pores is small, and it does not substantially contribute to the improvement of the coloring property. Conceivable. On the other hand, in the pores larger than this pore radius region, the coloring material and the solvent component easily penetrate, while the coloring material adsorbed near the entrance of the pore or inside the pore is affected by the light scattering of the pore itself. It is considered that the material hardly participates in the absorption of light, and conversely, the coloring property is lowered.

Therefore, measuring the pore volume in the region where the pore radius is 3 nm to 30 nm and in the region exceeding 30 nm is effective for measuring the color development performance of the formed image. The most appropriate method for measuring the physical properties of the pores in this region is a method using a nitrogen adsorption / desorption method. The pore radius and the pore volume were determined by vacuum degassing the pretreated sample at 120 ° C. for 8 hours, followed by the method of Barrett et al. (J. Am. Chem. So
c., Vol 73, 373, 1951). A more preferable measurement method is to measure the pore volume in a region having a pore radius of 3 nm to 20 nm and in a region exceeding 20 nm. In this range, when the coloring material is a dye, it is particularly preferable to measure a further improvement in the coloring property.

[Pore radius and pore volume of fine particle aggregate]
As described above, the pore radius of the fine particle aggregate is in the range of 3 nm to 30 nm from the viewpoint of prompt penetration of the coloring material, adsorption of the coloring material near the entrance of the pore or the inner wall, and prevention of aggregation of the coloring material inside the pore. Is considered preferable. In addition, a certain amount of capacity is required at the same time in order to take in a color material that only contributes to the improvement of the color developing property. In addition, it is considered that the number of pores in the fine particle aggregate increases due to an increase in the pore volume. Conceivable.

From these viewpoints, the liquid composition preferably used in the present invention has a pore volume of 0.4 ml / g or more in a pore radius range of 3 nm to 30 nm and a pore volume exceeding 30 nm. Pore volume at 0.1 ml /
g or less. By setting the pore radius and the pore volume in the above ranges, the penetration of the coloring material and the solvent component into the pores becomes more efficient, and light scattering in the pores is suppressed, so that Is improved.

For pores having a pore radius smaller than 3 nm,
The coloring material and the solvent component do not easily penetrate into the pores, and the pores of the fine particle aggregates do not substantially contribute to the improvement of the coloring property. Also,
When the pore volume exceeds 0.1 ml / g in the region where the pore radius exceeds 30 nm, there are many pores with large light scattering, and the coloring material adsorbed near the pore entrance or on the inner wall contributes to the color development. It becomes difficult to do. Further, when the pore volume in the region of the pore radius is less than this range, since the coloring material and the solvent component permeating into the inside of the fine particle aggregate are small, the coloring material adsorbed near or at the entrance of the pore is small. It is not preferable because the amount is small, and the contribution to the improvement of the coloring property is low.

More preferably, the pore radius is 3n.
0.4 ml / g of pore volume in the range of m to 20 nm
As described above, the pore volume in the region where the pore radius exceeds 20 nm is preferably 0.1 ml / g or less. 3n pores
By having a large amount in the range of a radius of m to 20 nm, especially when a dye is used as a coloring material, the color developability is further improved, and an image having a wider color reproduction range can be formed. The pore radius and pore volume of the fine particle aggregate formed from the liquid composition vary not only with the chemical species, shape, and size of the contained fine particles, but also with the solvent species, other additives, and their composition ratios. However, it is considered that the formation state of the fine particle aggregate can be controlled by controlling these conditions.

(Fine Particles) In the present invention, the desired action of the fine particles contained in the liquid composition is as follows: 1) When mixed with the ink, the coloring material is adsorbed without impairing the inherent coloring property of the coloring material. To do. 2) Dispersion stability is reduced when mixed with ink or applied to a recording medium, and remains on the surface of the recording medium. And the like. These functions may be achieved by one or more kinds of fine particles.

As a property for satisfying the function of 1), for example, the fine particles exhibit ionicity opposite to that of the coloring material. Thereby, the fine particles can electrostatically adsorb the coloring material. When the coloring material is anionic, cationic fine particles are used, and when the coloring material is cationic, anionic fine particles are used. Elements that adsorb the coloring material other than ionicity include the size and mass of the fine particles or the shape of the surface. For example, porous fine particles having a large number of pores on the surface exhibit unique adsorption characteristics, and can adsorb a coloring material by a plurality of factors such as the size and shape of the pores.

The function 2) is caused by interaction with ink and a recording medium. For this reason, what is necessary is just to achieve by each structure, For example, as a property of a fine particle,
It has the opposite ionicity to the ink composition component or the component of the recording medium. Also, the coexistence of an electrolyte in the ink or liquid composition affects the dispersion stability of the fine particles. In the present invention, it is desirable that either one of the above-mentioned functions 1) and 2) be obtained instantaneously. Further, it is preferable that both of the above-mentioned effects 1) and 2) be obtained instantaneously. Hereinafter, the liquid compositions containing the respective ionic fine particles will be specifically described.

[Cationic Liquid Composition] Examples of the cationic liquid composition include a liquid composition containing fine particles having a cationic group on the surface and an acid, and the fine particles are stably dispersed. In the present invention, as the cationic liquid composition, for example, an acid containing pH of 2 to 7 is used.
, The zeta potential is +5 to +90 m
V can be suitably used.

(Regarding pH and Zeta Potential) The zeta potential of the liquid composition will be described. The basic principle of the zeta potential will be described below. In general, in a system in which a solid is dispersed in a liquid, when there is free charge on the surface of a solid phase, a charged layer having an opposite charge appears in the liquid phase near the solid phase interface so as to maintain electrical neutrality. This is called an electric double layer, and the potential difference caused by the electric double layer is called zeta potential. When the zeta potential is positive, the surface of the fine particles is cationic, and when the zeta potential is negative, it is anionic. Generally, it is said that the higher the absolute value, the stronger the electrostatic repulsion acting between the fine particles and the better the dispersibility. At the same time, it is considered that the ionicity of the surface of the fine particles is strong. That is, it can be said that the higher the zeta potential of the cationic fine particles, the stronger the cationicity and the stronger the attraction of the anionic compound in the ink.

Further, the present inventors have conducted intensive studies. As a result, when a liquid composition having a zeta potential in the range of +5 to +90 mV is used, the colored portion formed on the recording medium is particularly excellent in coloring. It has been found that it exhibits characteristics. The reason is not clear, but probably because of the moderate cationicity of the fine particles, the anionic compound (anionic coloring material) does not rapidly aggregate, and the anionic compound is thinly and uniformly adsorbed on the surface of the fine particles. Therefore, it is considered that the coloring material hardly forms a huge lake, and as a result, the original coloring characteristics of the coloring material are expressed in a better state. Further, in the cationic liquid composition of the present invention, even after the anionic compound is adsorbed on the surface of the fine particles, the fine particles exhibit a weak cationic property and become in an unstable dispersion state, so that the fine particles are aggregated in the recording medium. It is considered that the ink is easily adsorbed on the surface of an anionic cellulose fiber or the like existing in the recording medium, and is likely to remain near the surface of the recording medium.

As a result, it is considered that the following excellent effects can be obtained. That is, in the image area where the amount of applied ink is large, such as a shadow portion and a solid portion, white haze and color unevenness are small, and the color uniformity is excellent. In addition, since the anionic compound is adsorbed to the fine particles and the color is extremely efficiently compared to the coated paper, the amount of the cationic fine particles can be reduced.
It does not impair the paper texture and has excellent scratch resistance of the recorded image. As a more preferable range of the zeta potential, for example, when a liquid composition containing cationic fine particles having a zeta potential in the range of +10 to +85 mV is used,
When solid printing is performed, boundaries between dots become less conspicuous, and further reduction of uneven streaks due to head scanning can be achieved. Further, the zeta potential becomes +15 to +65 m
When the liquid composition containing the cationic fine particles in the range of V is used, it is possible to obtain an image having extremely excellent color development regardless of the type of paper.

The pH of the cationic liquid composition of the present invention
Is preferably in the range of 2 to 7 at around 25 ° C. from the viewpoints of storage stability and adsorptivity of the anionic compound.
Within this pH range, when mixed with an anionic ink, the stability of the anionic compound is not significantly reduced, so that strong aggregation of the anionic compounds does not occur, and the color of the recorded image does not increase. It is possible to effectively prevent the degree of the image from decreasing or becoming a dull image. Further, when the content is within the above range, the dispersion state of the cationic fine particles is good, so that the storage stability of the liquid composition and the stability of ejection from the recording head can be favorably maintained. Furthermore, when mixed with the ink, the anionic substance is sufficiently adsorbed on the surface of the cationic fine particles, so that excessive penetration of the coloring material into the recording medium is suppressed, and an ink jet recorded image having excellent coloration can be obtained. can get. More preferred p
As the range of H, the pH is 3 to 6, and in this range, corrosion of the recording head due to long-term storage can be extremely effectively prevented, and the scratch resistance of the recorded image is further improved.

(Cationic Fine Particles) Next, the components constituting the cationic liquid composition of the present invention will be described. In order to achieve the above-mentioned effects, the cationic fine particles mentioned as the first component require that the surface of the particles themselves exhibit cationicity in a state of being dispersed in the liquid composition. By making the surface cationic,
When mixed with an anionic ink, the anionic coloring material is quickly adsorbed on the particle surface, and excessive penetration of the coloring material into the recording medium is suppressed, so that an ink jet recorded image having a sufficient image density can be obtained. can get. On the other hand, when the surface of the fine particles is not cationic and is present separately from the water-soluble cationic compound in the liquid composition, the coloring material aggregates around the cationic compound. In addition, since the coloring properties of the coloring material itself are impaired, it is difficult to achieve coloring properties comparable to those of coated ink-jet paper. Therefore, the fine particles used in the liquid composition of the present invention need to have a cationic surface, but not only fine particles that are essentially cationic, but also electrostatically anionic or neutral in nature. Even certain fine particles can be used in the liquid composition of the present invention as long as the fine particles have a surface cationized by the treatment.

The cationic fine particles suitably used in the present invention are sufficient for achieving the object of the present invention as long as the fine particles formed on the recording medium have pores formed in an aggregate. Therefore, there is no particular limitation on the material type of the fine particles. As specific examples, for example, cationized silica, alumina, alumina hydrate, titania, zirconia, boria, silica boria, ceria, magnesia, silica magnesia, calcium carbonate, magnesium carbonate, zinc oxide, Examples thereof include hydrotalcite and the like, composite fine particles thereof, organic fine particles, and inorganic-organic composite fine particles. And in the liquid composition of the present invention, these can be used alone or in combination of two or more.

In particular, when alumina hydrate is used as the fine particles, it is preferable because the surface of the particles has a positive charge.
Among them, alumina hydrate showing a boehmite structure by X-ray diffraction method is preferred in terms of excellent color developing property, uniform color, and storage stability. Alumina hydrate is defined by the following general formula. Al ₂ O _3-n (OH) _2n · mH ₂ O wherein n represents one of integers of 0 to 3, and m represents 0 to 1
It has a value of 0, preferably 0-5. The expression mH ₂ O often refers to a detachable aqueous phase that does not participate in the formation of the crystal lattice, so that m can also be a non-integer value. However, m and n do not become 0 at the same time.

In general, the crystal of alumina hydrate having a boehmite structure is a layered compound whose (020) plane forms a giant plane, and shows a diffraction peak specific to an X-ray diffraction pattern. In addition to complete boehmite, a structure called "pseudo-boehmite" containing an excess of water between layers of the (020) plane can be adopted. The X-ray diffraction pattern of this pseudo-boehmite shows a broader diffraction peak than boehmite.

Since boehmite and pseudo-boehmite cannot be clearly distinguished from each other, they are referred to as alumina hydrate having a boehmite structure (hereinafter referred to as alumina hydrate) unless otherwise specified in the present invention. The (020) plane has an interplanar spacing and a (020) crystal thickness when the diffraction speed 2θ is 1
The peak appearing at 4 to 15 ° is measured, and from the diffraction angle 2θ of the peak and the half width B, the plane spacing can be obtained by using the Bragg equation, and the crystal thickness can be obtained by using the Scherrer equation. it can. The plane spacing of (020) can be used as a measure of the hydrophilicity / hydrophobicity of the alumina hydrate.
The method for producing the alumina hydrate used in the present invention is not particularly limited, but any method capable of producing an alumina hydrate having a boehmite structure, for example, hydrolysis of aluminum alkoxide, hydrolysis of sodium aluminate, etc. Can be produced by a known method.

As disclosed in JP-A-56-120508, a boehmite structure is obtained by heat-treating amorphous alumina hydrate by X-ray diffraction at 50 ° C. or more in the presence of water. It can be changed and used. A method that can be particularly preferably used is a method of obtaining an alumina hydrate by adding an acid to a long-chain aluminum alkoxide and performing hydrolysis and peptization. Here, the long-chain aluminum alkoxide is, for example, an alkoxide having 5 or more carbon atoms, and further has 12 to 12 carbon atoms.
Use of the alkoxide of No. 22 is preferable because removal of the alcohol content and control of the shape of the alumina hydrate are facilitated as described later.

As the acid to be added, one or more of an organic acid and an inorganic acid can be freely selected and used. From the viewpoint of dispersibility and dispersibility, nitric acid is most preferred. After this step, it is also possible to control the particle size by performing hydrothermal synthesis or the like. When hydrothermal synthesis is performed using a dispersion of alumina hydrate containing nitric acid, nitric acid in the aqueous solution is incorporated as nitrate on the surface of the alumina hydrate to improve the water dispersibility of the hydrate. it can. In addition, after the hydrothermal synthesis, by appropriately adding an acid to the alumina hydrate slurry and adjusting the pH, the alumina hydrate slurry can be prepared with a small acid concentration and a very stable high solid content alumina hydrate slurry. . When such a slurry is used, there is no need to separately add an acid to be described later, and a liquid composition having excellent dispersion stability of alumina hydrate fine particles can be produced.

The above-mentioned method of hydrolysis of aluminum alkoxide has an advantage that impurities such as various ions are hardly mixed as compared with the method of producing alumina hydrogel or cationic alumina. Furthermore, long-chain aluminum alkoxides can be completely de-alcoholized from alumina hydrate, as compared with the case where a long-chain alcohol after hydrolysis uses, for example, a short-chain alkoxide such as aluminum isoproxide. There is also an advantage. It is preferred to set the pH of the solution at the start of the hydrolysis to less than 6. When the pH exceeds 8, the alumina hydrate finally obtained becomes crystalline, which is not preferable.

As the alumina hydrate used in the present invention, an alumina hydrate containing a metal oxide such as titanium dioxide can be used as long as it shows a boehmite structure by X-ray diffraction. . The content ratio of metal oxide such as titanium dioxide is 0.01 to 1.00 of alumina hydrate.
% Is preferable because the optical density is high, and more preferably 0.13 to 1.00% by mass. The adsorption speed of the coloring material is increased, and bleeding and beading are less likely to occur.
Further, the titanium dioxide needs to have a valence of +4. The content of titanium dioxide can be determined by dissolving in boric acid and by the ICP method. The distribution of titanium dioxide and the valence of titanium in the alumina hydrate can be analyzed by using ESCA.

The surface of the alumina hydrate can be etched with argon ions for 100 seconds and 500 seconds to examine the change in titanium content. When the valence of titanium is less than +4, the titanium dioxide may act as a catalyst, and the weather resistance of the recorded image may be reduced, or the recorded image may be easily yellowed.

The titanium dioxide may be contained only in the vicinity of the surface of the alumina hydrate, or may be contained up to the inside. Further, the content may change from the surface to the inside. It is more preferable that titanium dioxide is contained only in the vicinity of the surface because the electrical characteristics of alumina hydrate are easily maintained.

As a method for producing alumina hydrate containing titanium dioxide, for example, aluminum alkoxides described in “Surface Science”, 327, edited by Kenji Tamaru, ed. The method of producing by hydrolyzing a mixed solution of and titanium alkoxide is preferable. As another method, when hydrolyzing the mixed solution of the aluminum alkoxide and the titanium alkoxide, alumina hydrate can be added as a nucleus for crystal growth to produce the mixture.

Instead of titanium dioxide, silica, magnesium, calcium, strontium, barium, zinc,
An oxide such as boron, germanium, tin, lead, zirconium, indium, phosphorus, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, ruthenium, or the like can be used. For example, alumina hydrate containing silica is effective in improving the scratch resistance of a recorded image.

The spacing of the (020) plane of the alumina hydrate preferably used in the present invention is 0.614 nm to 0.626.
The range of nm is suitably used, and within this range, a liquid composition having good dispersion stability of alumina hydrate particles in the liquid composition and excellent storage stability and ejection stability can be obtained.
The reason for this is not clear, but if the plane spacing of the (020) plane is within the above range, the ratio of both hydrophobicity and hydrophilicity of alumina hydrate is within an appropriate range. It is presumed that the dispersion stability due to the appropriate repulsion and the appropriate balance of the wettability inside the ejection port improve the ejection stability of the liquid composition.

Further, the crystal thickness of the (020) plane of the alumina hydrate is preferably in the range of 4.0 to 10.0 nm. . According to the knowledge of the present inventors, since the interplanar spacing of the (020) plane and the crystal thickness of the (020) plane have a correlation, (0)
If the plane spacing of the (20) plane is within the above range, the crystal thickness of the (020) plane can be adjusted to a range of 4.0 to 10.0 nm.

The above-mentioned cationic fine particles used in the present invention have an average particle diameter measured by a dynamic light scattering method from the viewpoints of color development after printing, color uniformity and storage stability. Is preferably in the range of 0.005 to 1 μm. Within this range, excessive penetration into the inside of the recording medium can be effectively prevented, and a decrease in color developability and color uniformity can be suppressed.

Further, sedimentation of the cationic fine particles in the liquid composition can be suppressed, and a decrease in the storage stability of the liquid composition can be effectively prevented. More preferably, the average particle diameter is in the range of 0.01 to 0.8 μm, and if such fine particles are used, the abrasion resistance and the texture of the recorded image after printing on the recording medium are particularly improved. It will be preferable. More preferably, the average particle diameter is 0.03 to
Such fine particles are preferred because such fine particles are easy to form effectively in the target pore radius region in the pores of the fine particle aggregate formed on the recording medium.

(Physical Properties and Shape of Pore of Cationic Fine Particles) The above-mentioned cationic fine particles used in the present invention can efficiently form fine pores of fine particle aggregates formed on a recording medium. At the same time, in order to efficiently adsorb the colorant on the surface of the fine particles themselves, the fine particles having a maximum pore radius of 2 nm to 12 nm and a total pore volume of 0.3 ml / g or more in the above nitrogen adsorption / desorption method. Is preferred.
More preferably, the maximum pore radius of the fine particles is 3 nm to 10 n.
m and the total pore volume is 0.3 ml / g or more,
The fine pores of the fine particle aggregate formed on the recording medium are preferable because they are easily formed effectively in the target pore radius region.

When the BET specific surface area of the fine particles used in the present invention is in the range of 70 to 300 m ² / g, the coloring material is in a monomolecular state due to a sufficient adsorption point of the coloring material on the surface of the fine particles. More effectively remain near the surface of the recording medium, which contributes to the improvement of the coloring property.

The shape of the fine particles used in the present invention is as follows.
Fine particles can be dispersed in ion-exchanged water and dropped on a collodion membrane to prepare a measurement sample, which can be determined by observation with a transmission electron microscope. In the present invention, primary particles having a needle-like or plate-like shape, or spherical primary particles have a certain directionality in that pores are formed in the aggregates when forming fine-particle aggregates on a recording medium. A non-spherical shape such as a rod-like or necklace-like shape that forms secondary particles connected together can be suitably used.

According to the findings of the present inventors, a flat plate shape has better dispersibility in water than a needle-like or hair-like bundle (ciliform), and when a fine particle aggregate is formed, This is more preferable because the pore volume increases due to random orientation. Here, the hair bundle shape refers to a state in which needle-like fine particles are in contact with each other and gather together like a bundle of hair. In particular, among the alumina hydrates that can be preferably used in the present invention, pseudo-boehmite is described in the above literature (Rocek J., etal, Applie
d Catalysis, Vol. 74, pp. 29-36, 1991), it is generally known that there are cilia and other shapes.

The aspect ratio of the tabular grains is 5
It can be determined by a method defined in JP-A-16015. The aspect ratio is indicated by the ratio of the diameter to the thickness of the particle. Here, the diameter indicates the diameter of a circle having an area equal to the projected area of the particles when the alumina hydrate is observed with a microscope or an electron microscope. The aspect ratio is expressed by the ratio of the diameter indicating the minimum value to the diameter indicating the maximum value of the flat plate surface observed in the same manner as the aspect ratio. In the case of the hair bundle shape, the method of obtaining the aspect ratio is to obtain the diameter and length of each of the upper and lower circles by using the individual acicular alumina hydrate particles forming the hair bundle as a cylinder. , And the ratio can be determined. The most preferred shape of alumina hydrate is a flat plate having an average aspect ratio of 3 to 10.
In the hairy bundle, the average aspect ratio is preferably in the range of 3 to 10. When the average aspect ratio is within the above range, a gap is easily formed between the particles when the fine particle aggregate is formed, so that the porous structure can be easily formed.

The content of the cationic fine particles as described above in the liquid composition of the present invention may be determined as appropriate in accordance with the type of the substance to be used. % Is a preferable range for achieving the object of the present invention, more preferably 1 to 30%.
%, More preferably 3 to 15%. Within such a range, an image with excellent color development can be stably obtained regardless of the type of paper, and the storage stability and ejection stability of the liquid composition are particularly excellent.

(Acid) As described above, the liquid composition of the present invention preferably contains an acid and has a pH adjusted to 2 to 7. The acid as the second component is preferably By ionizing the surface of the cationic fine particles and increasing the surface potential, the dispersion stability of the fine particles in the liquid is improved, and the adsorptivity of the anionic compound (anionic colorant) in the ink is improved, and the liquid composition is improved. It plays a role in adjusting the viscosity of the product.
The acid suitably used in the present invention is not particularly limited as long as the desired physical properties such as pH, zeta potential or fine particle dispersibility can be obtained in combination with the cationic fine particles to be used. It can be freely selected from organic acids and the like.

Specifically, the inorganic acids include, for example, hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, boric acid, carbonic acid, and the like. Sulfonic acids, amino acids and the like.

Examples of the carboxylic acids include formic acid, acetic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, fluoroacetic acid, trimethylacetic acid, methoxyacetic acid, mercaptoacetic acid, glycolic acid, propionic acid, butyric acid, valeric acid, caproic acid and caprylic acid. Acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid,
Linoleic acid, linolenic acid, cyclohexanecarboxylic acid,
Phenylacetic acid, benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid, o-chlorobenzoic acid, m-chlorobenzoic acid, p-chlorobenzoic acid, o-bromobenzoic acid, m-bromobenzoic acid , P-bromobenzoic acid, o-nitrobenzoic acid, m-nitrobenzoic acid, p-nitrobenzoic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, tartaric acid, maleic acid, fumaric acid, citric acid , Phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, p
-Hydroxybenzoic acid, anthranilic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-methoxybenzoic acid,
m-methoxybenzoic acid, p-methoxybenzoic acid and the like.

Examples of the sulfonic acid include benzenesulfonic acid, methylbenzenesulfonic acid, ethylbenzenesulfonic acid, dodecylbenzenesulfonic acid,
4,6-trimethylbenzenesulfonic acid, 2,4-dimethylbenzenesulfonic acid, 5-sulfosalicylic acid, 1-
Sulfonaphthalene, 2-sulfonaphthalene, hexanesulfonic acid, octanesulfonic acid, dodecanesulfonic acid and the like can be mentioned.

The amino acids include glycine, alanine, valine, α-aminobutyric acid, γ-aminobutyric acid, and β-aminobutyric acid.
Alanine, taurine, serine, ε-amino-n-caproic acid, leucine, norleucine, phenylalanine and the like.

In the liquid composition of the present invention,
These can be used alone or in combination of two or more. Among them, the primary dissociation constant pka of acid in water
Is 5 or less, which is particularly excellent in dispersion stability of the cationic fine particles and adsorptivity of the anionic compound, and thus can be suitably used. Specific examples include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, acetic acid, formic acid, oxalic acid, lactic acid, citric acid, maleic acid, and malonic acid.

In the liquid composition of the present invention, the mixing ratio of the cationic fine particles (A) and the acid (B) in the liquid composition is such that A: B = 200: 1 to 5: 1 by mass, more preferably It is preferable that the ratio be in the range of 150: 1 to 8: 1 in order to improve the dispersion stability of the cationic fine particles and the adsorbability of the anionic compound to the surface of the fine particles.

(Other components) Next, other components constituting the cationic liquid composition will be specifically described. The cationic liquid composition of the present invention contains the above-mentioned cationic fine particles as an essential component, preferably contains the above-described acid, and, in addition, usually contains water as a liquid medium, and further contains a water-soluble organic solvent. And other additives.

The water-soluble organic solvent used in this case includes, for example, amides such as dimethylformamide and dimethylacetamide, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, and polyalkylenes such as polyethylene glycol and polypropylene glycol. Glycols, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, alkylene glycols such as diethylene glycol, ethylene glycol methyl ether, diethylene glycol monomethyl ether, triethylene glycol Lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether, ethanol, isopropyl alcohol, n Butyl alcohol, other monohydric alcohols such as isobutyl alcohol, glycerin, N
-Methyl-2-pyrrolidone, 1,3-dimethyl-imidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide and the like. The content of the water-soluble organic solvent is not particularly limited, but is, for example, 5 to 60%, more preferably 5 to 40% of the total mass of the liquid composition.

The liquid composition of the present invention may further contain, if necessary, a viscosity adjuster, a pH adjuster, a preservative,
Additives such as various surfactants, antioxidants and evaporation promoters, water-soluble cationic compounds and binder resins may be appropriately blended. The selection of the surfactant is particularly important in adjusting the permeability of the liquid composition into the recording medium. The water-soluble cationic compound can be freely selected and added within a range that does not inhibit the effects of the present invention, for the purpose of further imparting cationicity of the liquid composition.

The binder resin can be used together with the binder resin for the purpose of further improving the abrasion resistance of the cationic fine particles as long as the texture of the recording medium and the storage stability and ejection stability of the liquid composition are not impaired. For example, it can be freely selected from water-soluble polymers, emulsions, latexes and the like.

(Surface tension of liquid composition) The liquid composition of the present invention is more preferably colorless or white.
Toning may be performed according to the color of the recording medium. Further, a preferable range of various physical properties of the liquid composition as described above is such that the surface tension is 10 to 60 mN / m (dyn / cm), more preferably 10 to 40 mN / m (dyn / cm), and the viscosity is 1 -30 mPa · s (cP).

[Anionic Liquid Composition] The anionic liquid composition of the present invention is characterized in that fine particles having an anionic group on the surface are essential components and the fine particles are stably dispersed. However, it further contains a base and has a pH of 7 to
12 or a zeta potential of -5 to -9
Those having 0 mV are preferred.

(Regarding pH and Zeta Potential) As a result of extensive studies by the present inventors, the zeta potential of the liquid composition was -5.
Those having a range of -90 mV find that the cationic compound (cationic coloring material) in the ink is particularly efficiently adsorbed on the surface of the anionic fine particles, and exhibits particularly excellent color-forming properties on the recording medium. Was. The reason is not clear, but probably similar to the case of the cationic liquid composition described earlier, because of the moderate anionicity of the fine particles, the rapid aggregation of the cationic compound in the ink does not occur, It is considered that the coloring material does not form a huge lake by adsorbing thinly and uniformly on the surface of the fine particles, so that the original coloring characteristics of the coloring material are better exhibited.

Further, in the anionic liquid composition of the present invention, the dispersion becomes unstable after the cationic compound is adsorbed on the surface of the fine particles, and the fine particles are aggregated due to a change in concentration when the solvent component permeates on the recording medium. Therefore, it is considered that it is easy to remain near the surface.

As a result, it is considered that the following excellent effects can be obtained. That is, in the image area where the amount of applied ink is large, such as a shadow portion and a solid portion, there is little white haze and color unevenness, and the color uniformity is excellent. In addition, the cationic compound is adsorbed to the surface of the fine particles very efficiently as compared with the coated paper, and the color is formed, so that the amount of the anionic fine particles can be reduced. Scratch resistance of the recorded image is also improved. As a more preferable range of the zeta potential, for example, the zeta potential is -1.
When a liquid composition containing anionic fine particles in the range of 0 to -85 mV is used, the boundary between dots becomes less noticeable when solid printing is performed, and further reduction of uneven streaks due to head scanning is achieved. Is possible, and
When a liquid composition containing anionic fine particles having a zeta potential in the range of -15 to -65 mV is used, it is possible to obtain an image having extremely excellent color development regardless of the type of paper.

PH of anionic liquid composition of the present invention
Is preferably in the range of 7 to 12 at around 25 ° C. from the viewpoints of storage stability and adsorptivity of the cationic compound. Within this pH range, the stability of the cationic compound does not significantly decrease when mixed with the cationic ink, so that strong aggregation of the cationic compounds does not occur, and the saturation of the recorded image is reduced. Can be effectively prevented from dropping or becoming a dull image.

Further, when the content is in the above range, the dispersibility of the anionic fine particles is good, so that the storage stability of the liquid composition and the stability of ejection from the recording head can be maintained well. . Furthermore, when mixed with the ink, the cationic substance is sufficiently adsorbed on the surface of the anionic fine particles,
In order to suppress excessive penetration of coloring materials into the recording medium,
An ink jet recorded image having excellent coloring properties can be obtained. More preferably, the pH range of the liquid composition is from 8 to 11,
When the pH is within this range, corrosion of the recording head due to long-term storage can be extremely effectively prevented, and the scratch resistance of the recorded image is further improved.

(Anionic Fine Particles) Next, the components constituting the anionic liquid composition of the present invention will be described. In order to achieve the above-mentioned effects, the anionic fine particles mentioned as the first component preferably have an anionic surface when dispersed in the liquid composition. When mixed with a cationic ink by making the surface anionic, the cationic coloring material can be adsorbed on the particle surface, and the coloring material is suppressed from excessively penetrating into the recording medium. An ink jet recorded image having an image density can be obtained.

On the other hand, when the surface of the fine particles is not anionic and is present separately from the water-soluble anionic compound in the liquid composition, the coloring material aggregates around the anionic compound. As a result, the coloring property of the coloring material itself is impaired, so that it is difficult to achieve coloring properties comparable to those of coated ink-jet paper. Therefore, the fine particles used in the liquid composition of the present invention need to have an anionically charged surface. Not only fine particles which are essentially anionic, but also are inherently electrostatic or cationic. Neutral fine particles can be used as long as the fine particles have a surface anionized by the treatment.

The anionic fine particles suitably used in the present invention are sufficient to achieve the object of the present invention as long as the fine particles formed on the recording medium have pores formed in the aggregate. For this reason, the material type of the fine particles is not particularly limited. As a specific example, for example,
Examples include anionized silica, titania, zirconia, boria, silica boria, ceria, magnesia, silica magnesia, calcium carbonate, magnesium carbonate, zinc oxide, and the like, and composite fine particles, organic fine particles, and inorganic-organic composite fine particles thereof. And in the liquid composition of the present invention, these can be used alone or in combination of two or more.

The anionic fine particles used in the present invention are, similarly to the cationic fine particles described above, dynamic in view of the color development, uniformity of color and storage stability of the ink after printing. It is preferable that the average particle diameter measured by the light scattering method is in the range of 0.005 to 1 μm. More preferably, the average particle diameter is in the range of 0.01 to 0.8 μm. When such fine particles are used, the abrasion resistance and texture after printing on a recording medium are particularly preferable. More preferably, the average particle diameter is from 0.03 to 0.1.
Such fine particles are preferable because such fine particles are easy to form effectively in the target pore radius region in the fine pores of the fine particle aggregate formed on the recording medium.

(Physical Properties and Shape of Pore of Anionic Fine Particles) The anionic fine particles as described above used in the present invention can efficiently form fine pores of fine particle aggregates formed on a recording medium. At the same time, in order to efficiently adsorb the coloring material on the surface of the fine particles themselves, the fine particles in the nitrogen adsorption / desorption method have a maximum pore radius of 2 nm to 12 nm and a total pore volume of 0.3 ml / g or more. Is preferred.
More preferably, the maximum pore radius of the fine particles is 3 nm to 10 n.
m and the total pore volume is 0.3 ml / g or more,
The fine pores of the fine particle aggregate formed on the recording medium are preferable because they are easily formed effectively in the target pore radius region.

When the BET specific surface area of the fine particles used in the present invention is in the range of 70 to 300 m ² / g, the coloring material can be more easily converted into a monomolecular state because there are sufficient adsorption points of the coloring material on the surface of the fine particles. This effectively leaves the recording medium in the vicinity of the surface thereof, which contributes to the improvement of the coloring property.

The shape of the fine particles used in the present invention is as follows.
Fine particles can be dispersed in ion-exchanged water and dropped on a collodion membrane to prepare a measurement sample, which can be determined by observation with a transmission electron microscope. In the present invention, when forming fine particle aggregates on the recording medium, in terms of forming pores in the aggregates, the fine particles have a needle-like or plate-like shape, or spherical primary particles having a certain directionality. A non-spherical shape such as a rod shape or a necklace shape forming connected secondary particles can be suitably used. According to the findings of the present inventors, the flat shape has better dispersibility in water than the needle shape, and the pore volume is small because the orientation of the fine particles becomes random when the fine particle aggregate is formed. It is more preferable because it becomes larger.

The content of the anionic fine particles in the liquid composition as described above depends on the type of the substance to be used.
The optimum range may be appropriately determined, but is not more than 0.
The range of 1 to 40% is a preferable range for achieving the object of the present invention, more preferably 1 to 30%,
Further, a range of 3 to 15% is preferable. Within such a range, an image with excellent color development can be stably obtained irrespective of the type of paper, and the storage stability and ejection stability of the liquid composition are particularly excellent.

(Base) As described above, the anionic liquid composition of the present invention preferably contains a base and is adjusted to have a pH of 7 to 12. Base ionizes the anionic fine particle surface,
By increasing the surface potential, the dispersion stability in the liquid is improved, and at the same time, the function of improving the adsorptivity of the cationic compound (cationic colorant) in the ink and adjusting the viscosity of the liquid composition is achieved. The base suitably used in the present invention has a desired pH when combined with the anionic fine particles used.
There is no particular limitation as long as physical properties such as zeta potential and fine particle dispersibility can be obtained, and any of the following inorganic compounds and organic compounds can be freely used.

Specifically, for example, sodium hydroxide,
Lithium hydroxide, sodium carbonate, ammonium carbonate,
Ammonia, sodium acetate, ammonium acetate, morpholine, monoethanolamine, diethanolamine,
Triethanolamine, ethyl monoethanolamine,
Alkanolamines such as normal butyl monoethanolamine, dimethylethanolamine, diethylethanolamine, ethyldiethanolamine, normal butyldiethanolamine, dinormalbutylethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine can be used. Among these, particularly, a base having a primary dissociation constant pkb of 5 or less in water is preferably used because it is particularly excellent in dispersion stability of anionic fine particles and adsorptivity of a cationic compound (cationic coloring material). .

The mixing ratio of the anionic fine particles (A) and the base (B) in the liquid composition of the present invention is A: B on a mass basis.
= 200: 1 to 5: 1, more preferably 150: 1 to 1
A range of 8: 1 is preferable because the dispersion stability of the anionic fine particles and the adsorptivity of the cationic compound to the surface of the fine particles are excellent.

(Other components) Next, other components constituting the anionic liquid composition will be specifically described. The anionic liquid composition of the present invention contains the above-described anionic fine particles as an essential component, preferably contains the above-described base, and, in addition, usually contains water as a liquid medium, and further contains a water-soluble organic solvent. And other additives, for example, a viscosity adjuster, a pH adjuster, a preservative, various surfactants, an antioxidant, an evaporation promoter, a water-soluble anionic compound and a binder resin or the like. I don't care.

(Surface tension of liquid composition) The anionic liquid composition of the present invention is more preferably colorless or white, but may be toned in accordance with the color of the recording medium.
Further, as a preferable range of various physical properties of the liquid composition as described above, the surface tension is set to 10 to 60 mN / m (dyn / c).
m), more preferably 10 to 40 mN / m (dyn / c
m) and a viscosity of 1 to 30 mPa · s (cP).

(Method for Producing Liquid Composition) As a method for producing the liquid composition of the present invention containing the fine particles, a method generally used for dispersion can be selected and used. Specifically, a dispersing machine such as a roll mill, a sand mill, a homogenizer, an ultrasonic homogenizer, an ultrahigh-pressure emulsifier (eg, Nanomizer, etc.) in order to control the average particle size and particle size distribution of the fine particles in the liquid composition to the above ranges. Dispersion treatment using, or classification treatment by centrifugation, ultrafiltration, or the like is preferably used, and the dispersion particle diameter of the fine particles in the liquid composition can be made uniform by these treatment means.

<Ink> The ink used in the present invention contains the following pigments as coloring materials. Black ink: carbon black Cyan ink: C.I. I. Pigment Blue 15: 3 or 15: 4 (preferably CI Pigment Blue 1)
5: 3), magenta ink: C.I. I. Pigment Red 122 Yellow Ink: C.I. I. Pigment Yellow 74, 1
28, 147, 150, 154, 180 and 185 (preferably CI Pigment Yellow 74 and 128)

As a result of intensive studies by the present inventors, the use of the above-mentioned pigments in the ink enables realization of a wider color reproduction range, suppression of bleeding, and uniformity of color in plain paper recording which is the object of the present invention. It has been found that an excellent ink jet recording image having excellent smoothness, less solid streaks, and excellent scratch resistance can be formed.

Although the reason is not clear, the use of the specific pigment according to the present invention in the ink makes it possible to obtain a wide color reproduction with a smaller amount of liquid composition applied than when other pigments are used. It was possible to achieve the range, suppress bleeding, and achieve color uniformity. as a result,
It has been found that cockling of a recorded image can be reduced by reducing the total amount of liquid injected into the recorded image.

[Anionic ink] Next, the anionic ink constituting the ink set of the present invention in combination with the cationic liquid composition described above will be described. Here, the ink set refers to a combination of the liquid composition of the present invention and at least one kind of anionic ink containing an anionic substance (anionic colorant). Further, a combination of at least one type of ink obtained by removing the liquid composition of the present invention from this ink set is referred to as an ink subset.

The anionic ink used in the present invention contains a pigment as a coloring material, and further contains water, a water-soluble organic solvent and other components such as a viscosity adjusting agent, a pH adjusting agent, and the like.
Preservatives, surfactants, antioxidants and the like are included as necessary. Hereinafter, each component of these inks will be described.

In the anionic pigment ink, the anionic compound may be a pigment dispersant, or if the pigment dispersant is not anionic, an anionic compound different from the dispersant is added. It may be something. Of course, even when the dispersant is an anionic compound, the dispersant may further contain another anionic compound.

The carbon black used in the black pigment ink is a carbon black produced by a furnace method or a channel method and has a primary particle size of 15 to 40 μm.
m, specific surface area by BET method is 50 to 300 m ² / g,
Those having a DBP oil absorption of 40 to 150 ml / 100 g, a volatile content of 0.5 to 10% by mass, and a pH value of 2 to 9 are preferred.

For example, No. 1
2300, no. 900, MCF88, No. 40, N
o. 52, MA7, MA8, No. 2200B (or more,
Mitsubishi Kasei), RAVEN1255 (Colombia), REGAL
400R, REGAL660R, MOGUL L (above, made by Cabot), Color Black FW1, Color Black FW18, Color
Black S170, Color Black S150, Printex 35,
Commercial products such as Printex U (all manufactured by Degussa) can be used. Further, a prototype newly manufactured for the present invention may be used.

(Pigment Dispersant) As a pigment dispersant that can be used in the ink used in the present invention, a water-soluble dispersant having a function of stably dispersing a pigment in water or an aqueous medium due to the presence of an anionic group is used. Any resin can be used. In particular, the weight average molecular weight is 1,000
Those having a range of up to 30,000 are preferred. More preferably, the weight average molecular weight is in the range of 3,000 to 15,000. Specifically, for example, styrene, a styrene derivative, vinyl naphthalene, a vinyl naphthalene derivative, α,
hydrophobic monomers such as aliphatic alcohol esters of β-ethylenically unsaturated carboxylic acids, or acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid,
Examples include block copolymers, graft copolymers or random copolymers composed of two or more monomers selected from itaconic acid derivatives, fumaric acid and fumaric acid derivatives, or salts thereof. These resins are alkali-soluble resins that are soluble in an aqueous solution in which a base is dissolved.

Further, a homopolymer comprising a hydrophilic monomer or a salt thereof may be used. Also, polyvinyl alcohol,
Water-soluble resins such as carboxymethylcellulose and condensates of naphthalenesulfonic acid formaldehyde can also be used. However, when an alkali-soluble resin is used, there is an advantage that the viscosity of the dispersion can be reduced and the dispersion is easy. The water-soluble resin is preferably used in a range of 0.1 to 5% by mass based on the total amount of the ink.

The pigment ink which can be used in the present invention is constituted by dispersing or dissolving the above pigment and water-soluble resin in a water-soluble medium. A suitable aqueous medium in the pigment ink that can be used in the present invention is a mixed solvent of water and a water-soluble organic solvent. The water is not general water containing various ions, but ion-exchanged water (deionized water). It is preferred to use

When the dispersant is not an anionic polymer, it is preferable to further add an anionic compound to the ink containing the pigment described above. Examples of the anionic compound suitably used in the present invention include, in addition to the high-molecular substances such as the alkali-soluble resins described in the section of the pigment dispersant, low-molecular-weight anionic surfactants as described below. it can.

Specific examples of the low molecular weight anionic surfactant include, for example, disodium lauryl sulfosuccinate, disodium polyoxyethylene lauroylethanolamide ester sulfosuccinate, disodium polyoxyethylene alkyl sulfosuccinate, carboxylation Polyoxyethylene lauryl ether sodium salt, carboxylated polyoxyethylene tridecyl ether sodium salt, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene lauryl ether triethanolamine sulfate, polyoxyethylene alkyl ether sodium sulfate, sodium alkyl sulfate, alkyl Examples include, but are not limited to, triethanolamine sulfate. The preferred amount of the anionic substance as described above is in the range of 0.05 to 10% by mass, and more preferably 0.05 to 5% by mass, based on the total amount of the ink.

(Self-dispersion type pigment) As a pigment which can be used for anionic ink, a self-dispersion type pigment which can be dispersed in water or an aqueous medium without using a dispersant can also be used. . The self-dispersion type pigment has at least one kind of anionic hydrophilic group bonded directly or via another atomic group to the pigment surface. Examples of the anionic hydrophilic group include, for example, at least one kind selected from the following hydrophilic groups, and further another atomic group is an alkylene group having 1 to 12 carbon atoms, a substituent. And a phenylene group which may have a substituent or a naphthylene group which may have a substituent. _{-COOM, -SO 3 M, -SO 2} NH 2, -PO 3 HM, -PO 3 M 2 (M in the above formulas, represents hydrogen atom, an alkali metal, ammonium, or organic ammonium.)

The pigment anionically charged by the introduction of a hydrophilic group onto the surface of the pigment has excellent water dispersibility due to repulsion of ions, so that the pigment can be dispersed in an aqueous medium even when incorporated in an aqueous medium. A stable dispersion state is maintained without adding any of these. It is particularly preferable when the pigment is carbon black.

(Additional Components in Ink) In addition to the above components, a surfactant, an antifoaming agent, a preservative, or the like may be added to the ink in order to obtain an ink having desired physical properties as required. And a commercially available water-soluble dye or the like can be further added.

Examples of the surfactant include anionic surfactants such as fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, alkyl allyl sulfonates, polyoxyethylene alkyl ethers, and polyoxyethylene alkyl esters. , Polyoxyethylene sorbitan alkyl esters, acetylene alcohol, acetylene glycol, and other nonionic surfactants, and one or more of these can be appropriately selected and used. The amount used depends on the amount of the dispersant added,
Desirably, the content is 0.01 to 5% by mass based on the total amount of the ink. At this time, the surface tension of the ink is 30 mN / m (dyn / c
It is preferable to determine the amount of the activator to be added so as to satisfy m) or more. This is because, in the ink jet recording method used in the present invention, the occurrence of printing distortion (deviation of the impact point of the ink droplet) due to the wetting of the nozzle tip can be effectively suppressed.

As a method of preparing a pigment ink as described above, first, a pigment is added to an aqueous solution containing at least a resin for dispersing a pigment and water, and the mixture is stirred and then dispersed using a dispersing means described later. And, if necessary, centrifugation to obtain a desired dispersion. Next, the above-mentioned components are further added to the dispersion and stirred to form an ink.

When an alkali-soluble resin is used, it is necessary to add a base to dissolve the resin. At this time, the amount of the amine or the base for dissolving the resin must be at least one time the amount of the amine or the base obtained by calculation from the acid value of the resin. The amount of the amine or the base can be calculated by the following formula.

Further, if premixing is carried out for 30 minutes or more before the aqueous solution containing the pigment is subjected to the dispersion treatment, the dispersion efficiency of the pigment is improved. This premixing operation improves the wettability of the pigment surface and promotes the adsorption of the dispersant on the pigment surface.

The bases to be added to the dispersion when the alkali-soluble resin is used include, for example, organic amines such as monoethanolamine, diethanolamine, triethanolamine, amine methylpropanol and ammonia, potassium hydroxide, and the like. It is preferable to use an inorganic base such as sodium hydroxide.

On the other hand, the dispersing machine used for preparing the pigment ink may be any commonly used dispersing machine, and examples thereof include a ball mill and a sand mill.
Among them, a high-speed sand mill is preferable, for example,
Examples thereof include a super mill, a sand grinder, a bead mill, an agitator mill, a Glen mill, a dyno mill, a pearl mill, a Kobol mill (all trade names) and the like.

The ink used in the present invention may contain, if necessary, a water-soluble organic solvent, a surfactant,
Additives such as an H preparation agent, a rust inhibitor, a fungicide, an antioxidant, an evaporation promoter, a chelating agent, and a water-soluble polymer may be added.

The liquid medium for dissolving or dispersing the coloring material which can be used in the present invention is preferably a mixture of water and a water-soluble organic solvent. Specific water-soluble organic solvents, for example, methyl alcohol, ethyl alcohol,
n-propyl alcohol, isopropyl alcohol, n
-Butyl alcohol, sec-butyl alcohol, te
C1-C4 alkyl alcohols such as rt-butyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; ethers such as tetrahydrofuran and dioxane; polyglycols such as polyethylene glycol and polypropylene glycolicol. Alkylene groups such as alkylene glycols, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol and diethylene glycol contain 2 to 6 carbon atoms Lower alkyl ethers of polyhydric alcohols such as alkylene glycols, glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether S, N- methyl-2-pyrrolidone,
1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide, 2-pyrrolidone, ε
And cyclic amide compounds such as caprolactam and imide compounds such as succinimide.

The content of the water-soluble organic solvent is generally preferably from 1% to 40% by mass, more preferably from 3% to 30% by mass based on the total mass of the ink. Further, when the content of water in the ink is in the range of 30 to 95% by mass, the solubility of the coloring material is good, the increase in the viscosity of the ink can be suppressed, and the fixing property is sufficient. Can be satisfied.

The anionic ink used in the present invention can be used as a general aqueous writing instrument, but is particularly suitable when applied to an ink jet recording method of a type in which the ink is ejected by a foaming phenomenon of the ink by heat energy. It is characterized in that the ejection becomes extremely stable and no satellite dots are generated. However, in this case, the thermal properties (for example, specific heat, thermal expansion coefficient, and thermal conductivity) may be adjusted.

[Cationic Ink] Next, the cationic ink constituting the ink set of the present invention in combination with the anionic liquid composition described above will be described.
The term “ink set” as used herein refers to a combination of the liquid composition of the present invention and at least one ink containing a cationic substance (cationic colorant). Further, a combination of at least one type of ink obtained by removing the liquid composition of the present invention from this ink set is referred to as an ink subset.

The cationic ink used in the present invention contains a pigment as a coloring material, and further contains water, a water-soluble organic solvent and other components such as a viscosity adjusting agent, a pH adjusting agent,
Preservatives, surfactants, antioxidants and the like are included as necessary. Hereinafter, each component of these inks will be described.

In the cationic pigment ink, the cationic compound may be a pigment dispersant, or if the pigment dispersant is not cationic, a cationic compound different from the dispersant is added. It may be something. Of course, even when the dispersant is a cationic compound, the dispersant may further contain another cationic compound.

(Pigment Dispersant) The pigment dispersant in the ink used in the present invention may be any water-soluble resin having a function of stably dispersing the pigment in water or an aqueous medium due to the presence of a cationic group. Can be used. As a specific example, what is necessary is just what is obtained by superposition | polymerization of a vinyl monomer, and at least one part of the obtained polymer has cationic property. Examples of the cationic monomer for constituting the cationic moiety include salts of the following tertiary amine monomers and quaternized compounds thereof.

Specifically, N, N-dimethylaminoethyl methacrylate [CH ₂ ＣC (CH ₃ ) —COO—C ₂ H ₄ N (C
_{H 3) 2], N,} N- dimethylaminoethyl acrylate _{[CH 2 = CH-COO-} C 2 H 4 N (CH 3) 2], N, N- dimethylaminopropyl methacrylate [CH ₂ = C (CH _{3 ) -COO-C 3 H 6 N} (C
_{H 3) 2], N,} N- dimethylaminopropyl acrylate _{[CH 2 = CH-COO-} C 3 H 6 N (CH 3) 2], N, N- dimethylacrylamide _{[CH 2 = CH-CON (} CH 3 ) ₂ ], N, N-dimethylmethacrylamide [CH ₂ ＣC (CH ₃ ) -CON (CH ₃ ) ₂ ], N, N-dimethylaminoethylacrylamide [CH ₂ ＣＨCH-CONHC ₂ H ₄ N (CH ₃ ) ₂ ], N, N-dimethylaminoethyl methacrylamide [CH ₂ ＣC (CH ₃ ) -CONHC ₂ H ₄ N (C
_{H 3) 2], N,} N- dimethylaminopropyl acrylamide _{[CH 2 = CH-CONH-} C 3 H 6 N (CH 3) 2], N, N- dimethylaminopropyl methacrylamide [CH ₂ = C (CH _{3) -CONH-C 3 H 6} N (C
H ₃ ) ₂ ].

In the case of the tertiary amine, compounds for forming a salt include hydrochloric acid, sulfuric acid and acetic acid, and compounds used for quaternization include methyl chloride, dimethyl sulfate, benzyl chloride, and the like. Epichlorohydrin and the like. Among them, methyl chloride, dimethyl sulfate and the like are preferable in preparing the dispersant used in the present invention. The tertiary amine salt or the quaternary ammonium compound as described above behaves as a cation in water, and under neutralized conditions, acidity is a stable dissolution region.
The content of these monomers in the copolymer is preferably in the range of 20 to 60% by mass.

Examples of other monomers used in the constitution of the polymer dispersant include 2-hydroxyethyl methacrylate, acrylic esters having a hydroxy group such as acrylic esters having a long ethylene oxide chain in the side chain, and styrene. Examples of hydrophobic monomers such as series monomers and water-soluble monomers soluble in water near pH 7 include acrylamides, vinyl ethers, vinylpyrrolidones, vinylpyridines, and vinyloxazolines. As the hydrophobic monomer, a hydrophobic monomer such as styrene, a styrene derivative, vinyl naphthalene, a vinyl naphthalene derivative, an alkyl ester of (meth) acrylic acid, or acrylonitrile is used. In the polymer dispersant obtained by copolymerization, a water-soluble monomer is used in order to make the copolymer stably exist in an aqueous solution.
The hydrophobic monomer is used in an amount of 20 to 4% by mass in order to enhance the dispersing effect of the copolymer on the pigment.
It is preferable to use it in the range of 0% by mass.

(Self-dispersing Pigment) In the case of a cationically charged pigment, at least one hydrophilic group bonded directly or via another atomic group is selected from the following quaternary ammonium groups. Are combined. However, the present invention is not limited to these.

[0155]

In the above formula, R represents a linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group. The above cationic groups include, for example, NO ₃ ⁻ and CH ₃ COO ⁻ as counter ions.

As a method for producing a cationically-charged self-dispersible pigment having a hydrophilic group bonded thereto as described above, for example, a method of bonding an N-ethylpyridyl group having the following structure is exemplified. To explain, 3
-Amino-N-ethylpyridinium bromide.

The pigment charged cationically by the introduction of a hydrophilic group on the surface of the pigment has excellent water dispersibility due to repulsion of ions. Therefore, even when the pigment is contained in the ink, a dispersant or the like can be used. Maintains a stable dispersion state without the addition of. In particular, it is preferable that the pigment is carbon black.

(Surface Tension of Ink) Further, the cationic ink used in the present invention is not limited in terms of the ink penetrability of the recorded image when recorded on plain paper or the like and the good matching with the ink jet head. The surface tension at 25 ° C. is 30 to 68 mN /
m (dyn / cm) and viscosity are preferably adjusted to 15 mPa · s (cP) or less, preferably 10 mPa · s (cP) or less, and more preferably 5 mPa · s (cP) or less.

<Ink Concentration> The mass concentration of the coloring material components contained in the above-mentioned anionic and cationic inks is appropriately selected according to the kind of the pigment. -20%, particularly preferably 0.1-12%. Further, the mass concentration of the coloring material component is 0.3 to 7
In the range of%, with respect to the relationship between the concentration of the fine particles in the liquid composition and the concentration of the coloring material in the ink, the coloring material is 1.2 or less, particularly 1.0 or less with respect to the fine particles 1 on a mass basis. In this case, the color developability of an image formed under normal two-liquid recording conditions is particularly excellent.

<Method for Forming a Colored Part on a Recording Medium> Next, a method for forming a colored part on a recording medium of the present invention will be described. The method for forming a colored portion on a recording medium according to the present invention includes: (i) a step of applying an anionic or cationic ink containing a coloring material to the recording medium; and (ii) a polarity opposite to that of the ink. Applying a liquid composition containing fine particles having a charged surface to the recording medium in a dispersed state, wherein the ink and the liquid composition are in a liquid state on the surface of the recording medium. It is characterized by being provided so as to be in contact with. Hereinafter, a method of applying the liquid composition and the ink configured as described above to a recording medium will be described.

The method of forming a colored portion on a recording medium according to the present invention comprises the step (ii) of applying the liquid composition as described above on the recording medium, and the step of (ii) containing an anionic or cationic material containing a coloring material. (I) applying a neutral ink to a recording medium, and in this case, a liquid is formed in the colored portion forming region of the recording medium formed by the ink containing the coloring material, or the colored portion forming region and the vicinity thereof. The composition is applied so that the ink and the liquid composition are in contact with each other in a liquid state.
The term “colored portion forming region” as used herein refers to a region where ink dots are attached, and the vicinity of the colored portion forming region refers to a region that is about 1 to 5 dots outside the region where ink dots are attached. Refers to

In the method of forming a colored portion on a recording medium of the present invention, any of the above-mentioned methods can be used if the liquid composition of the present invention and the ink come into contact with each other in a liquid state on the recording medium. May be applied. Therefore, it does not matter which of the liquid composition and the ink is applied first on the recording medium. For example, step (i) may be performed after performing step (ii), or step (ii) may be performed after performing step (i). It is also preferable to perform the step (ii) after performing the step (i), and then perform the step (i) again. Further, when the liquid composition is first applied to the recording medium, the time from application of the liquid composition to the recording medium to application of the ink on the recording medium is particularly limited. However, it is preferable that the ink be applied to the recording medium almost simultaneously or within a few seconds in order to make them come into contact with each other in a liquid state.

(Recording Medium) The recording medium used in the above-described method of forming a colored portion on the recording medium of the present invention is not particularly limited. So-called plain paper such as bond paper is preferably used. Of course, a coated paper specially prepared for ink jet recording or a transparent film for OHP is also preferably used. Further, it can be suitably used for general high-quality paper and glossy paper.

(Method of Applying Liquid Composition) As a method of applying the liquid composition of the present invention on a recording medium, for example, a method of applying the liquid composition to the entire surface of the recording medium by a spray or a roller may be considered. More preferably, it is preferable to carry out the ink-jet method in which the liquid composition can be selectively and uniformly applied only to the colored portion forming region to which the ink is to be applied or to the vicinity of the colored portion forming region and the colored portion forming region. In this case, various ink jet recording methods can be used, but a method of discharging droplets using bubbles generated by thermal energy is particularly preferable.

<Inkjet Recording Apparatus> Next, the inkjet recording apparatus of the present invention will be described. An ink jet recording apparatus according to an aspect of the invention includes an ink storage unit that stores an anionic or cationic ink containing a coloring material, a first recording unit including an inkjet head that discharges the ink, and a liquid according to the present invention. A composition, preferably a liquid composition container containing a liquid composition containing fine particles whose surface is charged in a polarity opposite to that of the ink in a dispersed state, and an inkjet head for discharging the liquid composition And a second recording unit having: Hereinafter, these will be described.

FIG. 1 is a schematic perspective view showing an example of a schematic configuration of an ink jet recording apparatus to which the present invention is applied.
In FIG. 1, reference numeral 1 denotes a cartridge constituting a recording head for performing printing by discharging ink, and reference numeral 2 denotes a cartridge constituting a liquid composition discharge head for discharging a liquid composition. In the illustrated example, four print cartridges 1 and one liquid composition discharge cartridge 2 using inks of different colors are used.

Each of the cartridges 1 for printing has a structure in which an ink tank portion is provided at an upper portion and an ink discharge portion (printing portion) is provided at a lower portion. The liquid composition cartridge 2 has a structure in which a liquid composition tank portion is provided at an upper portion and a liquid composition discharge portion is provided at a lower portion. Further, the cartridges 1 and 2 are provided with connectors for receiving drive signals and the like. 3 is a carriage.

On the carriage 3, four print head cartridges (recording heads) 1 for printing with inks of different colors and one liquid composition discharge head cartridge (liquid composition discharge head) 2 are provided. Is mounted. The carriage 3 is provided with a connector holder for transmitting a signal for driving the recording head 1 and the liquid composition ejection head 2 and the like. Each of the head cartridges 1, 2 is connected via the connector holder. Is electrically connected to

Each recording head 1 stores inks of different colors, for example, yellow (Y), magenta (M), cyan (C), and black (B) inks.
In this figure, from the left side of the figure, print head cartridges (print heads) 1Y, 1M, 1C and 1B for yellow, magenta, cyan and black inks are mounted,
At the right end, a liquid composition discharge head cartridge (liquid composition discharge head) 2 containing the liquid composition is mounted.

In FIG. 1, reference numeral 4 denotes a scanning rail extending in the main scanning direction of the carriage 3 and slidably supporting the carriage 3. Reference numeral 5 denotes a driving belt for transmitting a driving force for reciprocating the carriage 3. is there. Also, 6, 7 and 8, 9
Are transport roller pairs disposed before and after the print position of the recording head for nipping and transporting the recording medium 10. The recording medium 10, such as paper, is guided and supported at a printing position by a platen (not shown) for regulating a printing surface flat in a press-contact state. At this time, the ejection port forming surfaces of the head cartridges (heads) 1 and 2 mounted on the carriage 3 protrude downward from the carriage 3 and are positioned between the recording medium transport rollers 7 and 9, and the platen (non- (Shown) in parallel with the recording medium 10 pressed against the guide surface.

A recovery unit 11 is provided in the vicinity of a home position set on the left side of the print area of the ink jet recording apparatus shown in FIG. The recovery unit 11 has four recording heads (head cartridges).
4 caps 1 corresponding to 1Y, 1M, 1C and 1B
One cap 13 corresponding to 2 and one liquid composition discharge head (head cartridge) 2 is provided so as to be vertically movable. When the carriage 3 is at the home position, the ejection ports of the heads 1 and 2 are sealed by capping the corresponding caps 12 and 13 against the ejection port formation surfaces of the heads 1 and 2 (capping). ) Is done. By capping, thickening and sticking of the ink due to evaporation of the ink solvent in the discharge port is prevented, and occurrence of defective discharge is prevented.

The recovery unit 11 is provided with each cap 1
A suction pump 14 communicating with the cap 2 and a suction pump 15 communicating with the cap 13 are provided. These pumps 14, 1
Reference numeral 5 denotes a case where ejection failure occurs in the recording head 1 or the liquid composition ejection head 2, and the ejection port forming surface is provided with a cap 1.
Used to perform the suction recovery process by capping at 2 and 13. Further, the recovery unit 11 includes two wiping members (blades) 1 made of an elastic member such as rubber.
6 and 17 are provided. The blade 16 is held by a blade holder 18, and the blade 17 is held by a blade holder 19.

In the schematic diagram of the present invention, the blade holders 18 and 19 are respectively raised and lowered by a blade lifting mechanism (not shown) driven by using the movement of the carriage 3, whereby the blades 16 and 19 are moved. 17
Is a position (wiping position) that protrudes (rises) for wiping ink or foreign matter attached to the ejection port forming surfaces of the heads (cartridges) 1 and 2 and a retracted (down) position that does not contact the ejection port forming surfaces (standby Position).
In this case, the blade 16 for wiping the recording head 1
1 for wiping liquid composition ejection head 2 with liquid
7 are configured to be able to move up and down independently of each other.

Then, when the carriage 3 moves from the right side (print area side) in FIG. 1 to the home position side,
Alternatively, when moving from the home position side to the print area side, the blade 16 comes into contact with the ejection port forming surface of each recording head 1, and the blade 17 comes into contact with the ejection port forming surface of the liquid composition ejection head 2, and the relative movement occurs. As a result, the wiping operation of the discharge port forming surfaces is performed.

FIG. 2 is a schematic perspective view showing a recording head (cartridge) 1 having a structure in which an ink discharge section and an ink tank are integrated. The liquid composition ejection head 2 has substantially the same configuration as the recording head 1 except that the liquid to be stored and used is a liquid composition. In FIG.
The recording head 1 has an ink tank unit 21 at an upper part and an ink discharge part (recording head part) 22 at a lower part. Further, the recording head 1 receives a signal for driving the ink discharge part 22 and the like. It has a head-side connector 23 for outputting a detection signal. The connector 23 is provided at a position aligned with the ink tank unit 21.

The recording head 1 has a discharge port forming surface 81 on the bottom surface side (the recording medium 10 side) in FIG. 2, and the discharge port forming surface 81 is formed with a plurality of discharge ports. A discharge energy generating element that generates energy necessary for discharging ink is disposed in a liquid path portion that communicates with each discharge port.

The Recording Head (Head Cartridge) 1
Denotes an ink jet printing unit that performs printing by discharging ink, and includes an ink discharging unit 22 and an ink tank 2.
1 is a replaceable ink jet cartridge. The recording head 1 is an ink-jet printing unit that discharges ink by using thermal energy, and includes an electrothermal converter for generating thermal energy. The recording head 1 performs printing by discharging ink from a discharge port by utilizing a pressure change generated by growth and shrinkage of bubbles caused by film boiling caused by thermal energy applied by the electrothermal transducer. It is.

FIG. 3 shows an ink discharge section 22 (liquid composition discharge section 22) of the recording head 1 (liquid composition discharge head 2).
It is a partial perspective view which shows the structure of A) typically. In FIG. 3, a plurality of discharge ports are formed at a predetermined pitch on a discharge port forming surface 81 facing a recording medium (print paper or the like) 10 with a predetermined gap (for example, about 0.5 to 2.0 mm). An outlet 82 is formed, and an electrothermal converter (heat-generating resistor or the like) 85 for generating energy for ink ejection along the wall surface of each liquid path 84 communicating the common liquid chamber 83 and each ejection port 82.
Are arranged. The plurality of ejection openings 82 are arranged in a positional relationship such that they are arranged in a direction crossing the moving direction (main scanning direction) of the recording head 1. In this manner, the corresponding electrothermal transducer 85 is driven (energized) based on the image signal or the ejection signal to cause the ink in the liquid passage 84 to boil, and the ink is ejected from the ejection port 82 by the pressure generated at that time. The recording head 1 is configured.

FIGS. 4 to 6 are schematic diagrams showing the wiping operation of the above-described ink jet recording apparatus. FIG. 4 shows a case where the carriage 3 moves from the print area side to the home position side. In FIG. 4, the recording head 1 and the liquid composition ejection head 2 on the carriage 4 move toward the home position from the right side (print area side) as shown in FIG. Then, as shown in (B), first, the blade 16 for the ink between the cap 12 for the ink and the cap 13 for the liquid composition rises, and the respective recording heads 1Y, 1Y, 1M, 1
C and 1B are sequentially wiped.

Further, as shown in FIG. 4 (C), after each recording head 1 has passed over the blade 17 for the liquid composition, the blade 17 for the liquid composition is raised, and as shown in FIG. 4 (D). Then, the ejection port forming surface of the liquid composition ejection head 2 is simultaneously wiped. After the ink blade 16 wipes the fourth recording head 1 and the liquid composition path blade 17 finishes wiping the liquid composition ejection head 2, the blades 16 and 17 descend, respectively. Wait at the standby position. In FIG. 4, when the carriage 3 moves from the right side (print area) in FIG. 1 to the home position side where the recovery unit 11 is located, wiping by the blades 16 and 17 is performed. However, the present invention is not limited to this, and wiping may be performed when the carriage 3 moves from the home position side to the right side (print area side) as shown in FIG.

In FIG. 5A, in FIG. 5A, the ink blade 16 and the liquid composition blade 17 are simultaneously raised, and the carriage 3 is moved to the right (toward the print area), whereby the recording head 1 is moved. And the liquid composition discharge head 2 are simultaneously wiped (B), and at the same time when the wiping of the liquid composition discharge head 2 is completed, only the blade 17 for the liquid composition is lowered to stand by, and the blade 17 for the ink remains as it is. Of the recording head 1 is performed (C). Finally, as shown in FIG. 5D, when the wiping of all the recording heads 1 is completed, the blade 16 for ink is lowered to complete a series of wiping operations.

By adopting the wiping direction as described with reference to FIG. 5, the droplets removed by the wiping and adhering to the blades 16 and 17 are scattered to the transport portion of the recording medium 10 by the elasticity of the blades. The danger of inadvertently soiling the recording medium 10 can be eliminated.

Further, as shown in FIG. 6, the wiping direction of the recording head 1 and the wiping direction of the liquid composition discharge head 2 may be different. In FIG. 6, for example, (A)
And (B), when the carriage 3 moves from the home position side to the right side (print area side), the recording head 1 is wiped by the ink blade 16,
As shown in (C) and (D), when the carriage 3 moves from the print area side to the home position side, only the liquid composition ejection head 2 may be wiped by the liquid composition blade 17. . By adopting such a wiping direction, ink scattered by the elastic force of the blade 16 adheres to the liquid composition discharge head 2, and conversely, the liquid composition scattered by the elastic force of the blade 17 is applied to the recording head 1. The inconvenience (danger) of adhesion can be eliminated or greatly reduced.

In FIG. 1, the cap 12 for the recording head 1 and the cap 1 for the liquid composition discharge head 2 are shown.
3 and independent of each other (specialized), and
Suction pump 1 connected to these caps 12, 13
Reference numerals 4 and 15 were separately (dedicated) for the recording head 1 and the liquid composition discharge head 2 independently. Thus, in the caps 12 and 13 and the pumps 14 and 15, these waste liquids can be treated without bringing the ink and the liquid composition reactive with the ink into contact with each other, and maintain high reliability. It becomes possible.

FIG. 7 is a schematic diagram showing a collection system for collecting the ink and liquid composition discharged from the pumps 14 and 15 into the waste ink tank. In FIG. 7, the recording head 1 is moved by a suction pump 14 communicating with a cap 12.
The waste ink sucked from the ink cartridge and the waste liquid sucked from the liquid composition discharge head 2 by the suction pump 15 connected to the cap 13 are introduced into the waste liquid tank 24 through independent paths so as not to leak out of the recording apparatus. Collected and stored.

[0187] The waste liquid tank 24 is configured so that a porous absorber 25 is filled in the inside thereof, and the absorber 25 absorbs and holds the waste liquid. This waste liquid tank 24
It is provided in the recording apparatus main body. In FIG. 7, the waste ink conduit 26 from the suction pump 14 for the recording head 1 and the waste liquid conduit 27 from the suction pump 15 for the liquid composition discharge head 2 are connected to each other at both ends of the waste tank 24 as shown in the figure. Connected to a remote location. By doing this,
Since the liquid composition and the ink in the waste liquid tank 24 come into contact with each other only when the liquid is sufficiently absorbed in the absorber 25, the amount of the liquid that can be absorbed and held by the porous absorber 25 is sufficiently ensured. be able to.

FIG. 8 shows the waste liquid recovery system shown in FIG. 7 in which the absorbers 25 in the waste liquid tank 24 are arranged in two upper and lower stages, the lower absorber 25A absorbs ink, and the upper absorber 25
It is a schematic diagram which shows the waste-liquid collection | recovery system comprised so that B might absorb a liquid composition. According to the configuration of FIG. 8, even if the lower ink absorber 25A overflows, the upper absorber 25
The dye in the ink reacts and is fixed by the upper absorber 25B by B and the liquid composition absorbed therein, so that the ink does not leak out and stain the inside and outside of the recording apparatus.

Another form of the ink jet recording apparatus includes an ink containing section containing an anionic or cationic ink containing a coloring material, and a liquid composition of the present invention, preferably the above ink. A liquid composition containing a liquid composition containing fine particles having a surface charged to a polarity in a dispersed state, and ink contained in the ink containing section and contained in the liquid composition containing section And an ink jet head for independently discharging the liquid compositions described above. Hereinafter, these will be described.

FIG. 10 shows such a cartridge 100.
As shown in FIG. 1, reference numeral 1003 in the figure denotes an ink storage unit that stores ink, and 1005 denotes a liquid composition storage unit that stores a liquid composition. As shown in FIG. 11, the cartridge is configured to be detachable from a recording head 1101 for ejecting each of the ink and the liquid composition, and when the cartridge 1001 is mounted on the recording head 1101, the liquid composition and the Ink is configured to be supplied to the recording head 1101.

The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated as described above, and the one in which they are integrated as shown in FIG. Can be

In FIG. 15, reference numeral 1500 denotes a recording unit, in which an ink storage section storing ink, for example, an ink absorber is stored, and the ink in the ink absorber has a plurality of orifices. Head part 1
It is configured to be ejected from 501 as ink droplets. As a material of the ink absorber, for example, polypropylene or polyurethane can be used. 1502
Is an atmosphere communication port for communicating the inside of the recording unit with the atmosphere.

Further, as another embodiment of the recording unit used in the present invention, the ink and the liquid composition are stored in respective storage sections in one ink tank, and each of the ink and the liquid composition is stored. A recording unit integrally provided with a recording head for discharging, specifically, for example, as shown in FIG. 12, a liquid composition in a container 1201L, a black ink in a container 1201Bk, and yellow, Cyan and magenta inks are stored in ink storage units 1201 respectively.
Y, 1201M, and 1201C, and a recording unit 1201 having a recording head 1203 having a separate ink flow path so that each ink can be ejected individually.

FIG. 16 is a schematic perspective view showing a schematic configuration of another embodiment of the ink jet recording apparatus according to the present invention. In FIG. 16, reference numeral 4 denotes a scanning rail which extends in the main scanning direction of the carriage 3 and slidably supports the carriage 3, and reference numeral 5 denotes a drive belt for transmitting a driving force for reciprocating the carriage 3. Also, 6, 7 and 8, 9
Are transport roller pairs disposed before and after the print position of the recording head for nipping and transporting the recording medium 10. The recording medium 10, such as paper, is guided and supported at a printing position by a platen (not shown) for regulating a printing surface flat in a press-contact state. At this time, the ejection port forming surfaces of the head cartridges (heads) 1 and 2 mounted on the carriage 3 protrude downward from the carriage 3 and are positioned between the recording medium transport rollers 7 and 9, and the platen (non- (Shown) in parallel with the recording medium 10 pressed against the guide surface.

In FIG. 16, a total of six head cartridges are positioned and mounted on the carriage 3.
In the present embodiment, from the left end in the drawing to the right side on the carriage 3, the yellow recording head 1Y, the magenta recording head 1M, the cyan recording head 1C, the black recording head 1B, the liquid composition discharge head 2, and the second Of black recording heads 1BB. The liquid composition discharge head 2 discharges a liquid composition reactive with a coloring material in the ink onto the recording medium 10. The second black recording head 1BB at the right end is a recording head that uses black ink used in sub-scanning printing in reciprocating printing and the like. In other words, the liquid composition ejection head 2 is disposed (to the right) next to the black recording head 1B in each of the above-described embodiments, and the black recording head 1BB is disposed to the next (right end). Have been.

In FIG. 16, a recovery unit 11 is provided on the left side of the print area. In the recovery unit 11, the recording heads 1Y and 1Y are arranged from left to right in accordance with the arrangement of the head cartridges 1 and 2. 1M, 1C and 1B
A cap 12 for capping the liquid composition discharge head 2 is disposed next (on the right side), and a second black recording head 1BB is further disposed on the right side (right end) thereof. A cap 12 for capping is arranged. Each cap is provided so as to be able to move up and down in the vertical direction. When the carriage 3 is at the home position, each head 1, 2
When the corresponding caps 12 and 13 are pressed against the discharge port forming surfaces, the discharge ports of the respective heads 1 and 2 are sealed (capping), whereby the amount of ink increases due to evaporation of the ink solvent in the discharge ports. Sticking and sticking are prevented,
The occurrence of ejection failure is prevented.

The recovery unit 11 has a suction pump 14 communicating with the caps 1 and 2 and a suction pump 15 communicating with the cap 13. These pumps 1
Reference numerals 4 and 15 are used to execute a suction recovery process by capping the ejection port forming surfaces with caps 12 and 13 when ejection failure occurs in the recording head 1 or the liquid composition ejection head 2. Further, a blade 17 for the liquid composition ejection head 2 is disposed between the fifth liquid composition cap 13 from the left end and the sixth (right end) black ink cap 12, and the right end of the right end cap 12. A blade 16 for each recording head 1 is arranged on the (print area side).

The blade 17 is the blade holder 1
9 and the blade 16 is held by a blade holder. In this embodiment, the blade holder 19 is moved up and down by a blade elevating mechanism (not shown) driven by using the movement of the carriage 3, whereby the blades 16 and 17 move the heads 1 and 2.
Is moved up and down between a protruding position (wiping position) for wiping ink and foreign matter attached to the discharge port forming surface and a retracted position (standby position) not in contact with the discharge port forming surface. In this case, the blade 16 for wiping the recording head 1 and the blade 17 for wiping the liquid composition ejection head 2 are configured to be able to move up and down independently of each other.

FIG. 17 is a schematic diagram showing the wiping operation of the ink jet recording apparatus of FIG. In FIG. 16, as shown in FIG.
Then, each head mounted on the carriage 3 moves from the right side (print area side) toward the home position. The raised printhead blade 16 sequentially wipes the printhead 1 as the carriage 3 moves to the left as shown in FIG. Then, as shown in (C), when the liquid composition discharge head 2 comes before (to the right of) the recording head blade 16, the blade 16 retreats (downs) to the standby position, and Contact with the liquid composition discharge head 2 is prevented.

Further, when the carriage 3 moves leftward and the liquid composition discharge head 2 passes through the recording head blade 6, as shown in FIG. Both blades 17 protrude (raise). As the carriage 3 moves to the left, the wiping of the liquid composition discharge head 2 by the blade 17 and the wiping of the rightmost recording head 1BB by the blade 16 are performed simultaneously as shown in FIG.
After wiping of all the heads 1 and 2 is completed, (F)
As shown in (2), both blades 16 and 17 are retracted (downward), and wait at the standby position.

In the embodiment shown in FIGS. 16 and 17, when the carriage 3 moves from the print area side (right side) to the home position side where the recovery unit 11 is located, the blade 1 is moved.
Although the wiping according to steps 6 and 17 is performed, the wiping direction is not limited to this, and the wiping may be performed when moving from the home position side to the right side (print area side).

In the ink jet recording apparatus shown in FIG. 16, the liquid composition according to the present invention having a reactivity with the coloring material in the ink from the liquid composition discharge head 2 is applied to the recording medium 10.
And the ink ejected from each recording head 1 is brought into contact with the recording medium 10 to form a recorded image. On the recording medium 10, the coloring material in the ink reacts with the liquid composition, so that the coloring material in the ink is adsorbed on the surface of the fine particles in a monomolecular state, and an image is formed by the fine particles. An image with excellent properties and color uniformity can be obtained.

Incidentally, in the recording apparatus used in the present invention,
In the above description, an ink jet recording apparatus that ejects ink droplets by applying thermal energy to ink and a liquid composition has been described as an example. However, a piezoelectric ink jet recording apparatus using a piezoelectric element can be similarly used.

[0204]

The present invention will be described more specifically with reference to the following Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist of the invention. In the following description, “parts” and “%” are based on mass unless otherwise specified.

The zeta potential in the text is determined by dispersing the liquid composition with ion-exchanged water so that the solid concentration of the fine particles becomes 0.1%, and then measuring the zeta potential using a BI-ZETA, manufactured by Brookhaven. plus, liquid temperature 20 ℃, use acrylic cell)
It is the value measured in. The pH was measured using a pH meter (HORIBA, Ltd.) at a liquid temperature of 25 ° C. for the prepared liquid composition.
Was measured using a Castany pH meter D-14). The average particle diameter of the fine particles is determined by dispersing the liquid composition in ion-exchanged water such that the solid content concentration of the fine particles is 0.1%, and then using a dynamic light scattering particle size distribution analyzer (BI-90, manufactured by Brookhaven). , A liquid temperature of 20 ° C, and an acrylic cell).

Preparation of Liquid Composition 1 After the following components were mixed and dissolved, the pore size became 1
The mixture was filtered under pressure through a membrane filter of μm to obtain Liquid Composition 1 of the present invention. Here, the alumina hydrate used above was obtained by the following synthesis method.

(Synthesis Example of Alumina Hydrate) Aluminum dodexide was produced by the method described in US Pat. No. 4,242,271. Next, U.S. Pat.
According to the method described in JP-A-02,870, the aluminum dodecoxide was hydrolyzed to produce an alumina slurry. Water was added to this alumina slurry until the solid content of the alumina hydrate became 7.9%. Alumina slurry p
H was 9.3. Add 3.9% nitric acid solution and adjust pH
Was adjusted to 5.3, and aged at 120 ° C. for 8 hours in an autoclave to obtain a colloidal sol. This colloidal sol was spray-dried at 83 ° C. to produce an alumina hydrate. The surface of the alumina hydrate is positively charged in water, and shows a cationic property. The pH of the cationic liquid composition 1 obtained above was 3.5, and the zeta potential was +39 mV.

[0208] The above-mentioned colloidal silica has been subjected to cation treatment on its surface, and exhibits cationicity in water. The pH of the cationic liquid composition 2 obtained above was 3.8, and the zeta potential was +68 mV.

(Preparation of Ink) Preparation of Yellow Inks 1 to 4 A pigment dispersion was prepared from the following components, and a yellow ink Y1 was prepared using the pigment dispersion. Further, using the same pigment dispersion, yellow inks Y2 to Y4 were obtained.

[Yellow Ink Y1] (Preparation of Pigment Dispersion) Styrene-acrylic acid copolymer (acid value 150, weight average molecular weight 6,000) 1.5 parts Monoethanolamine 1.0 part Diethylene glycol 5.0 Parts ・ Ion exchange water 81.5 parts

The above components were mixed and mixed in a water bath at 70
Heat to ° C. to completely dissolve the resin. To this solution, 10 parts of Pigment Yellow 74 and 1 part of isopropyl alcohol were added, and after premixing for 30 minutes, dispersion treatment was performed under the following conditions. Disperser: Sand grinder (made by Igarashi Kikai) Grinding media: zirconium beads, 1 mm diameter Filling ratio of grinding media: 50% (volume ratio) Grinding time: 3 hours Further centrifugation (12,000 rpm, 20 minutes)
Was performed to remove coarse particles to obtain a dispersion.

(Preparation of Yellow Ink Y1) Using the above-described pigment dispersion, components having the following composition ratios were mixed, and
An ink containing a pigment was prepared, and this was designated as a yellow ink Y1. -30.0 parts of the above pigment dispersion-7.5 parts of glycerin-5.0 parts of ethylene glycol-5.0 parts of 2-pyrrolidone-0.5 parts of acetylenol EH (manufactured by Kawaken Chemicals Co.)-0.5 parts of ion-exchanged water 0 copies

(Preparation of Yellow Ink Y2) Pigment Yellow 74 used in the preparation of Yellow Ink Y1
Pigment-containing yellow ink Y2 was produced in the same manner as in the production of yellow ink Y1, except that Pigment Yellow 128 was used in place of 10 parts.

(Preparation of Yellow Ink Y3) Pigment Yellow 74 used in the preparation of Yellow Ink Y1
Was prepared in the same manner as in the preparation of the yellow ink Y1 except that the pigment yellow 154 was used instead of 10 parts.

(Preparation of Yellow Ink Y4) Pigment Yellow 74 used in the preparation of Yellow Ink Y1
Was prepared in the same manner as in the preparation of the yellow ink Y1 except that 10 parts were replaced with Pigment Yellow 185.

Preparation of Magenta Ink 1 (Preparation of Magenta Ink M1) 10 parts of Pigment Yellow 74 used in preparation of yellow ink Y1 were
Pigment-containing magenta ink M1 was produced in the same manner as in the production of yellow ink Y1 except that Pigment Red 122 was used.

Preparation of Cyan Ink 1 and 2 (Preparation of Cyan Ink C1) Except that 10 parts of Pigment Yellow 74 used in the preparation of Yellow Ink Y1 were changed to Pigment Blue 15: 3, Pigment-containing cyan ink C in the same manner as in the production.
1 was produced.

(Preparation of Cyan Ink C2) A pigment was prepared in the same manner as in the preparation of yellow ink Y1, except that 10 parts of Pigment Yellow 74 used in the preparation of Yellow Ink Y1 were changed to Pigment Blue 15: 4. A cyan ink C2 was prepared.

Preparation of Black Ink 1 (Preparation of Black Ink Bk1) Pigment Yellow 74 used in the preparation of Yellow Ink Y1 was replaced with carbon black (MCF88, manufactured by Mitsubishi Chemical) in 10 parts. Acetylenol E in production
A pigment-containing black ink Bk1 was produced in the same manner as in the production of the yellow ink Y1, except that the amount of H was changed from 0.5 part to 0.1 part.

(Examples 1 to 6, Comparative Examples 1 and 2) The liquid compositions 1 and 2 of the present invention obtained as described above,
Inks Y1, Y2, Y3, Y4, M1, C1, C2, B
Printing was performed using the respective color inks of k1 in the combinations shown in Table 1 below. This was designated as Examples 1 to 6 of the present invention and Comparative Examples 1 and 2 using no liquid composition.

[0221]

In the method of forming a colored portion in the above embodiment, recording was performed on PPC paper (manufactured by Canon). Also,
The ink jet recording apparatus used at that time is shown in FIG.
A color image was formed using five recording heads shown in FIG. 3 using the same recording apparatus as shown in FIG. At this time, the liquid composition was first applied and attached on recording paper first, and then ink was attached.

Specifically, in the evaluation items (1) to (5), three-pass fine printing for printing the print area by three scans was performed, and in the evaluation item (6), two-pass printing was performed. At this time, the liquid composition was printed at a pixel position where any one of yellow, magenta, cyan, and black inks was printed for each pass. That is, the logical sum of the print data of yellow, magenta, cyan, and black for each pass was used as the print data of the liquid composition. The type of the fine mask at the time of the fine printing is not particularly limited, and a known technique can be used.

The recording head used here was 600 dpi.
And a driving frequency of 9.
6 kHz. When a 600 dpi head was used, the ejection amount per dot was 15 ng for the yellow, magenta, cyan ink and liquid composition, and 30 ng per dot for the black ink. These recording conditions are the same throughout the examples and comparative examples.

[Evaluation Method and Evaluation Criteria] Example 1 above
Each of the recorded images obtained in Example 6 and Comparative Examples 1 and 2 was evaluated by the following evaluation methods and evaluation criteria. The results are shown in Table 2.

(Method of Evaluating Recorded Image) (1) Chromogenicity RG of high-definition XYZ, CIELAB, and RGB standard image (SHIPP) (supervised by the High-Definition Standard Image Creation Committee, published by the Institute of Image Electronics Engineers of Japan)
The B color chart was printed using a printer, and the color charts were measured. The evaluation of the color developing properties was performed by calculating the three-dimensional spread of the color distribution (hereinafter referred to as a color gamut volume in the text) by the method described in the technical description and compared. At that time, image processing for forming a printed image was performed under the same conditions, and colorimetry was measured 24 hours after printing using a GRETAG spectrolino with a light source of D50 and a visual field of 2 °. The evaluation criteria are shown below. The ratio of the color gamut volume to the printed image of only ink (Comparative Example 1) was used as an evaluation criterion.

AAA: Color gamut volume ratio of 1.7 times or more AA: Color gamut volume ratio of 1.5 to less than 1.7 times A: Color gamut volume ratio of 1.4 to less than 1.5 times BB: Color The gamut volume ratio is from 1.2 to less than 1.4 times. B: The gamut volume ratio is from 1.0 to less than 1.2 times. C: The gamut volume ratio is less than 1.0 times.

(2) Uniformity After printing solid images of secondary colors red, blue and green using the above-mentioned printer, the color uniformity was evaluated visually with respect to white haze and color unevenness. In particular, colors having poor uniformity were evaluated. The evaluation criteria are as follows. A: Almost no white haze or color unevenness occurs. B: White haze and color unevenness are slightly visible along the paper fibers,
It is a level with virtually no problem. C: White haze and color unevenness are remarkably observed along the fiber of the paper.

(3) Unevenness Using a printer as described above, secondary red, blue and green solid images were printed, and the unevenness was visually evaluated. In particular, a color with poor unevenness was evaluated. The evaluation criteria are as follows. A: There is almost no uneven streaks. B: Streaks are slightly visible for each head scan, but there is practically no problem. C: White stripes are remarkably visible for each head scan.

(4) Scratch Resistance Solid images of inks of each color of yellow, magenta, cyan and black were printed using the printer described above.
Sixteen hours after printing, a silk-bon paper was overlaid on the recorded image, and a weight of 3.5 cm × 3.5 cm was further placed thereon, and 15 cm / sec while applying a pressure of 40 g / cm ^3.
The abrasion resistance of the recorded image was evaluated by pulling the silk paper at the speed of c. In particular, colors having poor abrasion resistance were evaluated. The evaluation criteria are as follows. A: Ink drop hardly occurs. B: Ink slightly adheres to the silk paper, but the discoloration of the recorded image is not noticeable. C: A large amount of ink adheres to the silbon paper, and the discoloration of the recorded image clearly occurs.

(5) Texture After printing solid images of yellow, magenta, cyan and black inks using the above-described printer, the texture of the recording medium was visually evaluated. The evaluation criteria are as follows. A: Both the recorded image and the unprinted portion have no uncomfortable feeling and leave the texture of plain paper. B: The texture differs between the recorded image and the unprinted portion, or the texture of the entire recording medium differs greatly from the texture of plain paper.

(6) Bleed Using a printer, solid cyan and black images were printed adjacent to each other, and the bleed at the boundary between colors was visually evaluated. The evaluation criteria are as follows. AA: Bleeding cannot be visually recognized. A: Bleeding is hardly noticeable. B: Bleeding is at a level where there is practically no problem. C: The bleeding is such that the boundary between the colors is not clear.

[0233]

[0234]

As described above, according to the present invention,
In particular, excellent color developability and color uniformity can be obtained while leaving the texture of plain paper, there are few streaks in the solid image area, and the recorded image has excellent scratch resistance and weather resistance, and furthermore, cockling of the recorded image An ink set, a method of forming a colored portion on a recording medium, and an ink jet recording apparatus.

In particular, by using an ink jet recording technique according to the present invention in which a liquid composition containing fine particles and an ink are used in combination, a color tone inherent in a color material in the ink is formed into an ink jet recorded image. It can be used for That is, there have been many inventions which specify a color material for each color ink constituting an ink set for forming an excellent multi-color image. However, most of them are selected on the premise that the color material is agglomerated on the recording medium, in other words, the color tone inherent in the color material cannot be obtained on the recording medium. As far as the present inventors know, the study of color materials suitable for the ink group constituting the ink set for obtaining a high-quality multi-color image on a recording medium using the color tone Has not been done. The present invention has found a color material suitable for an ink group constituting an ink set used to form a multi-color image on a recording medium by utilizing the original color tone of the color material. An extremely high-quality multi-color image having excellent color developability and well-balanced color can be obtained by the ink jet method.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view schematically showing an ink jet recording apparatus to which the present invention is applied.

FIG. 2 is a schematic perspective view of the head cartridge in FIG.

FIG. 3 is a partial perspective view schematically illustrating a structure of an ink ejection unit of the head cartridge in FIG. 1;

4A and 4B are schematic diagrams showing a wiping operation of the ink jet recording apparatus of FIG. 1, wherein FIG. 4A shows movement of each head from a print area side to a home position and elevation of an ink blade, and FIG. Wiping, (C) shows the wiping of the liquid composition discharge head, and (D) shows the lowering of each blade.

5A and 5B are schematic diagrams illustrating a wiping operation of the ink jet recording apparatus of FIG. 1, wherein FIG.
(B) moves each head from the home position to the print area side, (C) moves down the blade for liquid composition,
(D) shows the wiping of the recording head and the lowering of the ink blade, respectively.

FIGS. 6A and 6B are schematic diagrams showing a wiping operation of the ink jet recording apparatus of FIG. 1, in which FIG. 6A shows an elevation of an ink blade, and FIG. 6B shows movement of each head from a home position side to a print area side and a recording head. (C) shows the movement of each head from the print area side to the home position side, the standby of the ink blade and the rise of the liquid composition blade, (D) the movement of each head to the home position side and the liquid composition The wiping of the object discharge head is shown respectively.

FIG. 7 is a schematic diagram showing a waste liquid collection system of the ink jet recording apparatus of FIG.

FIG. 8 is a schematic diagram showing a partially modified example of the waste liquid recovery system of FIG. 7;

FIG. 9 is a schematic cross-sectional view illustrating a state of a colored portion when inkjet recording is performed on coated paper.

FIG. 10 is a schematic view showing one embodiment of an ink cartridge according to the present invention.

FIG. 11 is a schematic diagram of a recording head on which the ink cartridge of FIG. 10 is mounted.

FIG. 12 is a schematic diagram showing one embodiment of a recording unit according to the present invention.

FIG. 13 is a schematic cross-sectional view illustrating a state of a colored portion of an inkjet image according to the present invention.

FIG. 14 is a schematic process diagram illustrating a process of forming a colored portion of an ink jet recorded image according to the present invention.

FIG. 15 is a perspective view of a recording unit.

FIG. 16 is a partially broken perspective view schematically showing one embodiment of the ink jet recording apparatus according to the present invention.

17A and 17B are schematic diagrams illustrating a wiping operation of the ink jet recording apparatus of FIG. 16; FIG. 17A illustrates a rising of an ink blade, FIG. 17B illustrates a wiping of a recording head, FIG. D) shows the rise of both blades after the liquid composition has reached the proper position, (E) shows the wiping of the liquid composition and the second black ink head, and (F) shows the descent of both blades.

[Explanation of symbols]

1: recording head (ink discharge head cartridge) 2: liquid composition discharge head (liquid composition discharge head cartridge) 3: carriage 4: guide shaft (scanning rail) 5: drive belt 6, 7: transport roller 8, 9: Conveyance roller 10: Recording medium 11: Recovery unit 12: Cap (for recording head) 13: Cap (for liquid composition ejection head) 14: Suction pump (for ink) 15: Suction pump (for liquid composition) 16: Blade (for recording head) 17: Blade (for liquid composition discharging head) 18: Blade holder (for recording head blade) 19: Blade holder (for liquid composition discharging head blade) 21: Liquid storage tank 22: (Ink ) Discharge part 22A: (Liquid composition) discharge part 23: Head side connector 24: Waste liquid tank 25: Absorber 25A: Ink absorber 25B: Liquid composition absorber 26: Waste ink conduit 27: Waste liquid conduit 81: Discharge port forming surface 82: Discharge port 83: Common liquid chamber 84: Liquid path 85: Electrothermal converter (heating resistor) 901: Base paper 903: Ink receiving layer 905: Porous fine particles 907: Adhesive 909: Ink penetrating section 1001: Cartridge 1003: Ink storing section 1005: Liquid composition storing section 1101: Recording head 1201: Recording unit 1201Y: Yellow ink storage unit 1201M: Magenta ink storage unit 1201C: Cyan ink storage unit 1201L: Liquid composition storage unit 1201Bk: Black ink storage unit 1203: Recording head 1301: Recording medium 1302: Air gap between fibers of recording medium 1303: Fine particles 1305: coloring material 1307: (holds coloring material ) Aggregates of fine particles 1309: Aggregates of fine particles (near the fiber of the recording medium) I: Colored part IM: Main image part IS: Peripheral part 1400: Colored part 1401: Reaction part 1402: Ink outflow part 1403: Recording Medium 1404: Coloring material 1405: Void between fibers of recording medium 1406: Liquid composition 1407: Liquid pool 1409: Fine particles 1411: Aggregation of fine particles 1413: Ink 1415: Aggregate of fine particles with coloring material 1500: Recording Unit 1501: Head 1502: Atmospheric communication port

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yutaka Kurabayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2C056 FC02 2H086 BA02 BA05 BA51 BA55 BA60 4J039 AD02 AD03 AD06 AD09 AD10 AD11 AD12 AD13 AD14 AD17 AD20 BA04 BA13 BA14 BA15 BA16 BA21 BA30 BA31 BA32 BA33 BA34 BA35 BA36 BA37 BA38 BA39 BC07 BC09 BC10 BC11 BC12 BC13 BC14 BC15 BC18 BC19 BC25 BC33 BC35 BC36 BC40 BC50 BC51 BC54 BD03 BE01 BE02 BE12 BE28 BE30 BE33 CA03 EA29 EA42 EA44 EA46 EA47 GA24

Claims (22)

[Claims] 1. A colored ink set including at least a black ink, a cyan ink, a magenta ink, and a yellow ink each containing a pigment as a coloring material, and fine particles having a surface charged to a polarity opposite to that of the colored ink set are dispersed. An ink set comprising the liquid composition contained in a black state, wherein the black ink is carbon black and the cyan ink is C.I. I. Pigment Blue 15: 3
Or 15: 4, magenta ink is C.I. I. Pigment Red 122 and yellow ink are C.I. I. Pigment Yellow 74, 128, 147, 150, 154, 18
An ink set comprising at least one selected from 0 and 185. 2. The black ink is carbon black, and the cyan ink is C.I. I. Pigment Blue 15: 3, magenta ink is C.I. I. Pigment Red 122 and yellow ink are C.I. I. The ink set according to claim 1, comprising Pigment Yellow 74. 3. The black ink is carbon black, and the cyan ink is C.I. I. Pigment Blue 15: 3, magenta ink is C.I. I. Pigment Red 122 and yellow ink are C.I. I. 2. The ink set according to claim 1, wherein the ink set contains CI Pigment Yellow 128. 4. A colored ink comprising a black ink, a cyan ink, a magenta ink and a yellow ink, and the liquid composition has a zeta potential of +5 to +
The ink set according to claim 1, wherein the ink set is 90 mV. 5. The colored ink comprising a black ink, a cyan ink, a magenta ink and a yellow ink, is anionic, the liquid composition further contains an acid, and the pH is adjusted to 2 to 7. Item 3. The ink set according to any one of Items 3. 6. The ink set according to claim 5, wherein the primary dissociation constant pKa of the acid in water is 5 or less. 7. A colored ink comprising a black ink, a cyan ink, a magenta ink and a yellow ink is cationic, and the liquid composition has a zeta potential of -5 to-.
The ink set according to claim 1, wherein the ink set is 90 mV. 8. A colored ink comprising a black ink, a cyan ink, a magenta ink and a yellow ink is cationic, and the liquid composition further comprises a base,
Is adjusted to 7 to 12;
The ink set according to the item. 9. A base having a first-order dissociation constant pKb of 5 in water.
The ink set according to claim 8, wherein: 10. The liquid composition has an average particle diameter of 0.00
The ink set according to any one of claims 1 to 9, further comprising fine particles having a size in a range of 5 to 1 µm. 11. The ink of claim 1, wherein the yellow ink, the magenta ink and the cyan ink are composed of dark and light inks.
11. The ink set according to any one of items 10 to 10. 12. A method for forming a colored portion on a recording medium using the ink set according to claim 1, wherein (i) a step of applying the colored ink to the recording medium, and (ii) the colored ink. And a process of applying a liquid composition containing a water-soluble polymer to a recording medium, the dispersion comprising fine particles having a surface charged to the opposite polarity to the opposite polarity, and applying the liquid ink to the surface of the recording medium. And applying the liquid composition to the recording medium in a liquid state. 13. The method according to claim 12, wherein the step (i) is performed at least after the step (ii) is performed. 14. The method according to claim 12, wherein the step (ii) is performed at least after the step (i) is performed. 15. After the step (i) is performed, the step (i)
The method for forming a colored portion according to claim 12, wherein i) is performed, and thereafter, step (i) is performed again. 16. The ink jet recording method according to claim 11, wherein the application of the colored ink to the recording medium in the step (i) is performed by a method of discharging the colored ink from an orifice according to a recording signal. The method for forming a colored portion according to the above item. 17. The method according to claim 16, wherein the ink jet recording method is a method in which the ink is ejected from an orifice by applying thermal energy to the ink. 18. The method according to claim 11, wherein the application of the liquid composition to the recording medium in the step (ii) is performed by an ink jet recording method of discharging the liquid composition from an orifice according to a recording signal. 2. The method for forming a colored portion according to claim 1. 19. The method for forming a colored portion according to claim 18, wherein the ink jet recording method is a method of applying thermal energy to the liquid composition to discharge the liquid composition from the orifice. 20. An ink storage section containing the colored ink according to claim 1, a first recording unit including an ink jet head for discharging the ink, and a liquid composition according to claim 1. A liquid composition storage section that contains the liquid composition;
An ink jet recording apparatus comprising: a second recording unit having an ink jet head for discharging the liquid composition. 21. An ink container containing the colored ink according to claim 1, a liquid composition container containing the liquid composition according to claim 1, and coloring contained in the ink container. An ink jet recording apparatus comprising: an ink jet head for independently discharging ink and a liquid composition stored in the liquid composition storage section. 22. The ink-jet recording apparatus according to claim 20, wherein the ink-jet head is a thermal ink-jet head that ejects liquid by applying thermal energy.