JP2001246841A - Recording medium, manufacturing method thereof, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high ink absorption rate, no stickiness, high transparency, excellent fixability of pigment ink, excellent color reproducibility of dye ink, and sufficient image density and gradation. Provided is a recording medium which is excellent in water resistance and ink fixing property and can obtain an image without cracks. SOLUTION: In a recording medium in which at least one porous organic resin layer is formed on a base material, the porous organic resin layer has an organic fine particle having both a hydrophilic group and a hydrophobic group, and a water-absorbing binder. And the pores, the pore distribution curve of the porous organic layer has a maximum peak in the range of pore radius 3 nm to 300 nm, and the pore volume is 0.2
cm ³ / g or more, the recording medium having a pH of 5.2 or more in the porous organic resin layer measured according to JIS P 8133, a method for producing the same, and excellent recording on the recording medium. An image forming method that can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium in which a porous organic resin is laminated on a base material, a method for manufacturing the same, and recording on the recording medium, preferably by an ink jet recording method. To an image forming method.

[0002]

2. Description of the Related Art An ink jet recording method is a method of recording an image, a character, or the like by flying fine droplets of ink on a recording medium (paper or the like) by various operating principles and attaching the droplets to a recording medium (paper or the like). It has features such as noise, easy multi-coloring, high flexibility of recording patterns, and no need for development and fixing, and is rapidly spreading in various applications. Furthermore, according to the multi-color ink jet recording method, it is possible to form a multi-color image comparable to multi-color printing by a conventional plate-making method or printing by a color photographic method, and furthermore, the number of copies to be made When the number is small, a printed matter can be obtained at a lower cost than ordinary multicolor printing or printing, and is being widely applied to the field of full-color image recording.

[0003] Regarding the ink jet recording system,
Conventionally, with the demand for improvement of recording characteristics such as high-speed recording, high-definition, and full-color recording, improvements have been made in ink-jet recording apparatuses and recording methods. On the other hand, advanced characteristics are required. In the ink jet recording system, ink containing a large amount of water or an aqueous solvent such as a mixture of water and an organic solvent is used because it is necessary to eject ink droplets from a nozzle toward a recording medium at high speed. . Therefore, in order to obtain a recorded image with a high color density, a large amount of ink must be used. In addition, since the ink droplets are continuously ejected, a beading phenomenon in which the dots of the ink are joined may occur, and the image may be disturbed. To prevent this beading phenomenon, the recording medium to be used is required to have a large ink absorption amount and a high ink absorption speed.

In order to solve such a demand, conventionally,
Various types of recording media have been proposed. For example, in order to improve absorption, color development and resolution, a porous material containing inorganic particles (alumina hydrate etc.) on a substrate as described in JP-A-2-276670. Many recording media having a quality layer have been proposed.
Further, there has been proposed a recording medium having an ink fixing layer composed of a transparent resin which is dissolved or swelled by a solvent of the ink on a substrate, as described in JP-A-4-101880. Further, as disclosed in Japanese Patent Publication No. 2-18146 and Japanese Patent Publication No. 2-31673, a recording medium comprising a thermoplastic resin particle on a substrate, an emulsion, and a latex has been proposed. Further, the present inventor has proposed Japanese Patent Application Laid-Open No. H11-192775 for pigment ink.

Japanese Patent Application Laid-Open No. 9-99634 discloses that an ink receiving layer contains a polymer complex of a basic polymer and a styrene / (meth) acrylic acid polymer, and is prepared by dissolving a binder and organic particles once. And a recording medium comprising a polymer complex obtained by mixing. Japanese Patent Application Laid-Open No. Hei 9-156211 discloses that an ink receiving layer provided on a transparent support is composed of crosslinked polymer fine particles having an average particle diameter of 200 nm or less and a water-soluble resin, and has a sheet transmittance. A recording medium characterized by being at least 80% is described. Japanese Patent Application Laid-Open No. 10-324053 proposes a recording medium characterized in that a porous film is formed from an emulsion containing carboxycellulose nitrates and a film-forming aid.

[0006]

The above-described prior arts have various methods for recording media, such as ink absorbency, resolution, image density, transparency and glossiness of a formed image. Despite improvements in characteristics, even with such a recording medium, due to the remarkable progress of recent recording devices, the number of prints has been increased as high-speed printing at a quality comparable to silver halide photography has been performed. That problem has been occurring.

For example, a recording medium having a porous layer made of inorganic particles (alumina hydrate or the like) formed on the surface thereof disclosed in JP-A-2-276670 is excellent in terms of image quality and gloss. However, since the surface is easily damaged, transport damage is likely to occur depending on the transport method of the printer. Further, since the combination of the inorganic particles and the organic resin is used for a transmission type such as an OHP film, the transparency of the sheet is high, and the shadow of the sheet is projected even when the HAZE is relatively low. is there. This is considered to be caused by the difference in the refractive index between the inorganic particles, the organic resin, and the pores. Also, when the pigment ink is printed, since the pores of the porous layer are smaller than the size of the pigment component of the pigment ink, the pigment component is deposited on the surface and is not taken into the porous layer. There is a problem that the scratch resistance of the image is inferior. Further, as a problem peculiar to a recording medium having a porous layer mainly composed of inorganic particles, there is a problem such as yellowing of the sheet itself.

Further, in the case of a recording medium having an ink fixing layer using a resin that dissolves or swells more in an ink solvent as described in JP-A-4-101880, the drying speed of the ink is low, After recording, there is a problem of stickiness for a while. Furthermore, there was a problem that sufficient water resistance of the ink receiving layer itself could not be obtained, and dye migration occurred due to the influence of humidity. Furthermore, since there is no water resistance of the ink receiving layer itself, when recording using a pigment coloring material,
There is also a problem that a crack occurs in a printing portion (particularly, a solid portion).

[0009] Further, an ink receiving material comprising thermoplastic resin particles, an emulsion and a latex is provided on a substrate such as a recording medium described in Japanese Patent Publication No. 2-18146 and Japanese Patent Publication No. 2-3673. In the recording medium on which the layer is formed, the ink absorption speed is high, but since only the gap between the thermoplastic resin particles is used, the thickness of the ink receiving layer must be increased in order to obtain sufficient ink absorption capacity. Therefore, there is a problem that the transparency and the film strength of the film decrease. The recording medium described in JP-A-11-192775 has been improved so as to correspond to a pigment ink, but is subjected to heat treatment after image formation, and its structure and technical It is a different idea.

In a recording medium proposed in Japanese Patent Application Laid-Open No. 9-99634, in which an ink receiving layer is composed of a combination of an inder and organic particles, a binder and organic particles are once dissolved in a solvent and then mixed. Since the ink receiving layer is formed by the polymer complex obtained by this method, in this configuration, sufficient holes are not formed in the ink receiving layer,
Sufficient ink absorption speed cannot be expected.

An average particle size of 200 nm is set on a transparent support described in JP-A-9-156211.
In a recording medium provided with an ink receiving layer composed of the following crosslinked polymer fine particles and a water-soluble resin, since a water-soluble resin is used as a binder, a sufficient gap can be formed between the fine particles. In addition, it is difficult to increase the absorption speed by the gaps because the water-soluble resin is mixed in a large amount in the range of 1: 1 to 1:10 with respect to the fine particles.

In the case of a recording medium described in JP-A-10-324053, in which a porous film is formed from an emulsion containing carboxycellulose nitrates and a film-forming aid, the emulsion particles Gap is formed, but it is difficult to adjust the pH in the porous film layer,
In the case where the pH is low and the pH is on the acidic side, the dye undergoes specific aggregation after printing the ink, and the color may be different from that of the conventional dye.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a high ink absorption speed, prevent stickiness of a formed image,
High transparency, good fixability of pigment ink, prevention of cracks in the printed area, excellent color reproducibility of dye ink, sufficient image density and gradation when forming images Obtained recording medium capable of forming an image having excellent water resistance and fixability, a method of manufacturing the recording medium, and image formation capable of performing good recording on the recording medium It is to provide a method.

[0014]

The above objects are achieved by the present invention described below. That is, the present invention relates to a recording medium in which at least one porous organic resin layer is formed on a base material, wherein the porous organic resin layer comprises organic fine particles having both a hydrophilic group and a hydrophobic group; And a pore distribution curve of the porous organic layer has a maximum peak in a pore radius range of 3 nm to 300 nm, and a pore volume of 0.2 cm ³ / g or more, and the pH of the porous organic resin layer measured according to JIS P 8133 is 5.2 or more.

The present invention also relates to a method for producing a recording medium in which at least one or more porous organic resin layers are formed on a substrate, wherein the organic fine particles having both a hydrophilic group and a hydrophobic group, a water-absorbing binder, Contains basic substances and JIS
An aqueous dispersion having a liquid pH of 5.2 or more measured according to Z8802 is used as a coating liquid, and the coating liquid is coated on a substrate and dried to form a porous organic resin layer. A method for manufacturing a recording medium. Furthermore, the present invention relates to an image forming method for forming an image by applying ink to a recording medium, wherein the recording medium is used as the recording medium, and in particular, an ink is applied to the recording medium. This is an image forming method using an ink jet recording system when applying the image.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to preferred embodiments. FIG. 1 is a schematic sectional view showing an example of the recording medium of the present invention. This recording medium 1
No. 00 is formed by laminating a porous organic accepting layer 102 on a substrate 101. As the base material 101, various kinds of conventionally known members can be used without limitation. For example, polyester such as polyethylene terephthalate, polycarbonate,
Various plastic sheets such as fluorinated resin such as ETFE, photographic paper used for silver salt photography, loose paper, specially processed paper such as resin coated paper, paper without surface processing such as plain paper, etc. No. Among these, by using plastic sheets having high surface properties as a base material, the glossiness of the surface of the porous organic resin layer formed thereon can be enhanced, and the sheet can be used as a glossy film sheet. Furthermore, by using a transparent substrate, OHP
It can be used as a transmission type recording medium such as a sheet.

The porous organic resin layer 102 laminated on the surface of the base material as described above is mainly formed of an organic resin material composed of a combination of organic fine particles which are hardly melted by heat and a water-absorbing binder. Characterized in that a void is formed in the hole. In order to perform recording on the recording medium 100 of the present invention having such a configuration, ink may be applied onto the porous organic resin layer 102. When the ink is applied, first, the solvent component in the ink passes through the voids of the porous organic resin layer 102, and the water-absorbing binder existing between the organic fine particles plays a role of absorbing the ink. Sufficient ink absorption is performed step by step.

According to the recording medium of the present invention, when the pore size of the porous organic resin layer 102 constituting the recording medium is measured by pore distribution, the maximum peak of the pore radius in the distribution curve is 3 nm. It is characterized in that it has a range of up to 300 nm. In other words, when the pore distribution curve of the porous organic resin layer 102 has a maximum peak at a place where the pore radius is smaller than 3 nm, sufficient ink absorption ability cannot be obtained.
If there is a maximum peak at a place larger than 00 nm, ink bleeding occurs. Furthermore, in order to obtain sufficient absorption and transparency, it is particularly preferable that the porous organic resin layer 102 be configured so that the maximum peak of the pore radius in the void distribution curve is in the range of 7 nm to 100 nm. More preferred. The maximum peak is the maximum peak.

The ink absorption capacity of the porous organic resin layer 102 can be adjusted by the distribution ratio of pores due to voids in the porous organic resin layer and the thickness thereof. The recording medium has a pore volume of 0.2 cm ³ / g in order to increase the ink absorption speed.
So that More preferably, 0.5 cm ³
/ G or more and 1.0 cm ³ / g or less. The voids here are formed as a pore structure connected in two-dimensional and three-dimensional directions such as up and down and right and left directions in the porous organic resin layer, and having such a structure, the ink is applied. In this case, the solvent component in the ink can quickly pass through the pores. Note that the pore distribution due to the voids in the porous organic resin layer 102 was measured by a nitrogen adsorption / desorption method.

In the porous organic resin layer constituting the recording medium of the present invention, the formation of the optimum voids satisfying the above-mentioned properties is determined by the type and the size of the organic fine particles which are the material for forming the porous organic resin layer. The diameter and shape, etc., the type of water-absorbing binder used with the organic fine particles, the mixing ratio of the water-absorbing binder to the organic fine particles, and the relationship between the drying conditions and the film thickness when the porous organic resin layer is formed. Can be adjusted appropriately. As a result, in the porous organic resin layer, a sufficient absorption function of the solvent of the ink is obtained, and a sufficient ink absorption property is achieved.

The organic fine particles used in the present invention are organic pigments that are not substantially plasticized by heat. In the present invention, as the organic fine particles, those having both hydrophilic and hydrophobic groups in the skeleton thereof are used. However, when preparing a coating liquid, it is possible to mix with various aqueous resin aqueous solutions. In addition, by appropriately adjusting the ratio between the hydrophilic group and the hydrophobic group, it is possible to ensure the water resistance of the formed film itself. Specifically, known resins, for example, acryl-based, ester-based, vinyl chloride-based, vinyl acetate-based, styrene-based, butadiene-based, cellulose-based resin and the like, and those chemically modified, such as ester A resin composed of a derivative that has been converted to an ether or an ether can be used.

In the present invention, it is particularly preferable to use, as the organic fine particles, organic fine particles dispersed in a solvent by an emulsion polymerization method in which a nonionic emulsifier or a cationic emulsifier is used to carry out emulsion polymerization. . Specifically, it is obtained by selecting one or more monomers having a highly hydrophilic substituent introduced therein as a monomer, mixing the above-described emulsifier with a liquid medium such as water or an organic solvent, and performing emulsion polymerization. To use. Further, among these organic fine particles, when used in combination with a water-absorbing binder, the refractive index thereof is 1.40 to form a porous organic resin layer without lowering the transparency.
It is preferred to select 1.60.

In order to make the above-described voids of the desired size exist in the porous organic resin layer, organic fine particles having a glass transition temperature that is difficult to melt are used. Is preferred. At this time, since the porous organic resin layer forms a film by adhesion of a binder generated by drying by heat, a drying condition of 100 ° C. or more is assumed. Therefore, the glass transition temperature of the organic fine particles to be used is preferably higher than 120 ° C. to 220 ° C. Among these, those obtained by emulsion polymerization of an acrylic or cellulose monomer are preferably used because a low refractive index and a high Tg can be obtained. As a specific example, among the cellulose-based materials, nitrate esters of carboxycellulose described in JP-A-9-324053 are particularly preferable as the material to be used for the recording medium material of the present invention. Can be

Further, in order to obtain pores formed by voids with low light scattering as described above, the particle diameter should be 5 nm to 300 n.
It is preferable to use organic fine particles in the range of m.
That is, if the particle size is too small, it is difficult to obtain a sufficient number of voids, and if the particle size is too large, the effect of light scattering increases, and the transparency of the porous organic resin layer may be reduced. is there. Further, the organic fine particles have a particle diameter of 5n.
It is more preferable to use one having a range of m to 250 nm. Note that a general method such as a quasi-elastic laser light scattering method (dynamic light scattering method) was used for measuring the particle diameter of the organic fine particles. Since the recording medium of the present invention uses the organic fine particles as described above, unlike the conventional recording medium in which a porous layer containing inorganic particles such as alumina hydrate is formed, the recording medium of the sheet itself is used. Yellowing is unlikely to occur, and the occurrence of whitening around the printed portion during ink absorption rarely occurs.

In the recording medium of the present invention, desired voids are formed in the porous organic resin layer by bonding the organic fine particles having the above-described materials and particle diameters by bonding with a binder. , In the porous organic resin layer,
In order to form more voids, it is desirable that the organic fine particles used have an irregular shape. It is also effective to use organic fine particles having many irregularities. Examples of a method for producing an irregularly shaped organic fine particle include, for example, a method in which existing fine particles are used as a seed (seed) and a monomer is absorbed and polymerized, or a method of modifying the surface of the particle is used. Fine particles can be formed.

In order to increase the porosity in the porous organic resin layer, it is desirable to use porous organic fine particles. As a specific method of forming the porous organic fine particles, a method of forming a bridge structure in the particles by introducing a crosslinking component when forming the organic fine particles is exemplified. It is effective that the porosity in the organic fine particles is a porosity that does not impair the transparency of the porous organic resin layer depending on the relationship with the particle diameter of the particles. In the above-described range of the particle diameter, if the porosity is in the range of 5 to 70%, it is possible to obtain voids effective for ink absorption and to maintain the transparency of the film.

As the emulsifier used in the emulsion polymerization for forming the organic fine particles described above, for example, any one of an anionic emulsifier, a nonionic emulsifier, and a cationic emulsifier can be used alone or in combination. In particular, in ink-jet recording applications, since the ionicity of the ink used for image formation is anionic, the porous organic resin layer, which is the ink receiving layer, should be cationic, which is the opposite ionicity. Therefore, it is preferable to use a cationic emulsifier since the ink fixability can be improved. Further, it is also possible to improve the ink fixability by adding a cationic substance separately, but in this case, when the anionic emulsifier is used in the above, there is no adverse effect such as gelation and thickening. Thus, the amount of the cationic substance that can be added is limited. Therefore, in this case, it is preferable to use a nonionic and cationic emulsifier or a mixed emulsifier thereof.

The organic fine particles used in the present invention are characterized in that they have both a hydrophobic group and a hydrophilic group in their structure. By using an organic fine particle having a hydrophobic group, the porous organic resin layer can have excellent water resistance. That is, at the time of application of the ink, or when water is scattered from the outside to the ink applied on the recording medium, and further, when the image is affected by humidity, the ink receiving layer is prevented from dissolving. That is, the water resistance of the coating layer of the porous organic resin layer can be controlled.
On the other hand, by using a hydrophilic organic fine particle, it is possible to effectively prevent the repelling or bleeding of the ink which occurs at the time of applying the ink. Furthermore, by using organic fine particles having an appropriately controlled balance between hydrophobicity and hydrophilicity, the ink receiving properties, fixing properties, water resistance, suppression of stickiness of the receiving layer, and properties such as transparency and color forming properties are further improved. Can be improved.

Specific examples of the above-mentioned hydrophobic group include, for example, an ester group, an allyl group, a vinyl group and a propenyl group, and more specifically, a method of substituting a hydrophilic group by a known method. Used. Specific examples of the hydrophilic group include, for example, a carboxyl group, a sulfone group, a hydroxyl group, a cationic group such as a phosphonic acid group, an amino group, an amide group, and a cationic group such as an ethyleneimine group. In order to control the degree of hydrophilicity, these are appropriately selected from these hydrophilic groups and introduced into the structure of the organic fine particles.
Furthermore, by considering the degree of hydrophobicity and hydrophilicity of these hydrophobic groups and hydrophilic groups, the above various properties can be improved by designing the structure of the organic fine particles by combining several substituents. Can be.

The water-absorbing binder used when forming the porous organic resin layer constituting the recording medium of the present invention together with the organic fine particles described above is a dispersion, that is, a water-soluble binder. Those which maintain the particle state that has not been performed (resin emulsion) are preferably used. Examples of the dispersion include an aqueous dispersion, a dispersion in a mixed solvent of water and alcohol, and a dispersion in an organic solvent, such as an acrylic resin, a urethane resin, a styrene resin, a butadiene resin, and a polyester resin. Resin and the like, and a water-absorbing resin emulsion such as a mixture, a copolymer and a complex thereof can be appropriately selected and used. Further, the resin of these dispersions is mainly composed of a dispersion resin, and may be used in combination with a soluble resin. As the soluble resin, a water-soluble resin, a resin soluble in a mixed solvent such as water and alcohol, and a resin soluble in an organic solvent can be used. As such, for example, polyvinyl alcohol, cellulose-based resin, polyester-based resin, urethane-based resin,
Examples include, but are not limited to, gelatin, polyacrylamide, and polyvinylpyrrolidone. These resins may be used in combination with additives such as a crosslinking agent, a curing agent, a plasticizer, a modifier, and a gelling agent.

In the present invention, it is necessary to bind the organic fine particles with the above-mentioned binder to form a film and to form an appropriate gap between the organic fine particles. The properties of the resin, such as the above, and the mixing ratio between the organic fine particles and the binder are important.
In the present invention, a binder having water absorbency is used as the binder, and when the ink is applied, in addition to the solvent in the ink entering the gap between the organic fine particles, the absorption is further improved. Can be done. Therefore, the balance between the formation of voids and the absorbency of the binder is also important. Furthermore, in the recording medium of the present invention, the voids between the organic fine particles of the porous organic resin layer mainly serve the function of absorbing the ink, and the ink is sufficiently absorbed in the voids. Since the water-absorbing effect of the water-absorbing binder is exhibited, the water resistance of the water-absorbing binder itself is not impaired, and as a result, it is possible to prevent the occurrence of cracks in the solid portion even when recording with the pigment ink. .

Specifically, the binder used in the present invention is more preferably the above-mentioned dispersion, that is, a resin emulsion. The use of such a material is desirable because the binder is uniformly present between the organic particles during drying and coating, and has a molten form that does not fill the voids. Regarding the glass transition point of the binder to be used, it is preferable that the binder has a temperature characteristic that is opposite to the organic fine particles and can be quickly melted.
Those having a glass transition point of 40 ° C. can be preferably used. Further, in order not to fill the voids, a material having a gelling property that suppresses binder migration may be used. Specific examples include those having a thermosensitive gelling property.

Further, as the above resin emulsion,
It is preferable to use one having a particle size in the range of 20 nm to 500 nm. When a resin emulsion smaller than this range is used, the resin emulsion almost approaches the behavior of the resin dissolved in the solvent, and the resin emulsion disposed between the organic fine particles may gradually melt during drying. It may not be possible to obtain the advantage of securing the void amount. On the other hand, if a material larger than this range is used, the distribution and size of the voids are likely to vary. More preferably, those having a particle diameter in the range of 30 nm to 200 nm may be used. For measuring the particle diameter of the resin emulsion, a general method such as a quasi-elastic laser light scattering method (dynamic light scattering method) may be used.

The mixing ratio of the organic fine particles and the binder (P: B
Ratio) is preferably in the range of 1: 1 to 20: 1 in terms of solid content ratio. More preferably, it is used in the range of 2: 1 to 10: 1. Further, regarding the absorption capacity of the binder, the balance between the ink absorption capacity and the ink absorption speed is considered, and it depends on which one is given priority.
Those having an absorption capacity of 0.0 times are preferred. Here, the absorption capacity refers to the amount of ink that can be absorbed per volume of the binder.

As a characteristic of the porous organic resin layer composed of the organic fine particles, the binder and the void, the value of the pH in the porous organic resin layer is further important. The pH of the porous inorganic particle layer, which uses an inorganic material such as alumina or silica and a binder conventionally used for a recording medium and has voids, has a relatively low value. That is, the acid side is often used. However, unlike the case of the porous inorganic particle layer, in the system using the organic fine particles and the binder of the present invention, when the pH in the layer is low, particularly when the pH is lower than 4.5, the ink is applied. On the surface, extreme agglomeration or the like occurs, and a color different from the original color of the used dye occurs, or the dye generates metallic luster on the surface, causing a mottled phenomenon. On the other hand, in the recording medium of the present invention, the above-mentioned problem is solved by adjusting the pH in the porous organic resin layer to 5.2 or more.

Although the reason is not certain, in the case of the porous organic resin layer in which the voids are formed by organic resin particles as in the present invention, unlike the pores of the inorganic fine particles, the adsorption ability of the dye is relatively high. It is presumed that the ink is quickly taken into the voids by adjusting the inside of the layer so as to have an appropriate pH since the ink is weak. Such effects are:
It has been found that it is closely related to the relationship between the type of the fine particles and the size of the voids, and it appears that the voids are remarkably exhibited when the voids are 300 nm or less and further 100 nm or less. Further, in the present invention, the pH of the porous organic resin layer is adjusted to 5.2 to 8.5.
It has been found that more preferable effects can be obtained by adjusting to the range described above.

As described above, p in the porous organic resin layer
As a method of adjusting H, the type and number of the hydrophilic groups of the resin which is the basic material of the organic fine particles are adjusted, and the type and number of the hydrophilic groups are adjusted when the binder is brought into an emulsion state. These methods make it possible to appropriately adjust the pH. Furthermore, it can be adjusted by adding a basic substance, for example, sodium hydroxide, ammonia, amine or the like at the time of preparing the coating liquid. In the present invention, the pH in the layer was measured by a method specified in JIS P 8133.

In the recording medium of the present invention, the porous organic resin layer 102 may contain a small amount of porous inorganic particles in order to improve the ink absorbency in addition to the above-mentioned constituent materials. Good. As the porous inorganic particles used at this time, specifically, for example, silica, alumina hydrate,
Examples include calcium carbonate, magnesium carbonate, magnesium oxide, kaolin, talc, calcium sulfate, barium sulfate, titania, lead oxide, zinc carbonate, silicic acid, sodium silicate, calcium silicate, and clay. Among these porous inorganic particles, it is preferable to use finely divided particles in order to obtain the transparency of the porous organic resin layer. Specifically, ultrafine particles of silica or alumina hydrate are preferred. As the particle size, it is more preferable to use primary particles having a particle size of 100 nm or less, and further preferably 10 nm or less. When the porous inorganic particles are used in combination, the content is 0.1 wt.
It is preferable to be in the range of 1% to 10%. If the content of the inorganic particles is too large, the transparency may be reduced or cracks may occur.

The recording medium of the present invention is based on the above-described coating solution containing the organic fine particles and the binder, a basic substance for adjusting the pH, and, if desired, porous inorganic particles. It is obtained by forming a porous organic resin layer on a substrate by applying it on a material and drying it. At this time, viscosity, pH, dispersibility and the like are important as physical properties of the coating liquid used, and the viscosity is appropriately adjusted depending on the coating method used. Specifically, it is preferable to be in the range of 10 cP to 500 cP. Regarding the pH, the coating solution pH is preferably set to 5.2 or more in order to obtain the above-mentioned intra-layer pH. In addition, the measurement of the pH of the solution is performed according to JIS Z88
02.

Furthermore, in order to obtain uniform coating properties and transparency, it is necessary to ensure sufficient dispersibility and storage stability. Therefore, the coating liquid further includes a dispersing agent, a thickening agent, a lubricant, a fluidity modifier, within a range not to impair the purpose of the present invention.
A surfactant, an antifoaming agent, a waterproofing agent, a foam inhibitor, a release agent, a deodorant, and the like can be added. Coating of a coating liquid having the composition described above on a substrate is performed, for example, by a blade coating method, an air knife coating method, a roll coating method, a flash coating method, a gravure coating method, a kiss coating method, a die coating method, and an extrusion method. , A slide hopper method, a curtain coat method, a spray method, or the like.

At this time, the coating amount of the coating liquid on the base material may be appropriately selected according to the desired use of the recording material and the like. Can not be absorbed into
After the ink is attached to the porous organic resin layer, bleeding or overflow occurs, which is not preferable. If it is too thick,
It is not preferable because the strength of the porous organic resin layer is reduced, and a coating film defect occurs during coating and drying, and a portion where the ink absorption amount cannot be secured partially occurs. On the other hand, if the thickness is too large, the transparency is reduced, and the sharpness of a recorded matter or an image may be impaired. for that reason,
In order to secure the absorption amount and maintain the strength as an overall film,
The preferred thickness of the porous organic resin layer is the thickness after drying,
The thickness is preferably 5 to 50 μm.

In the present invention, a porous organic resin layer can be obtained by subjecting the coating layer provided on the substrate as described above to a drying treatment by heating as necessary. By such a drying treatment, an aqueous medium (dispersion) evaporates, and a film is formed by bonding by fusion of a binder.
The conditions for the drying treatment can be appropriately selected according to the composition of the coating solution used. Drying is generally used hot air drying oven,
The infrared drying oven may be used alone or in combination as appropriate.

The image forming method of the present invention is characterized in that an image is formed by applying ink to the recording medium configured as described above. At this time, an ink mainly containing a coloring material (dye or pigment), a water-soluble organic solvent and water is used. As the dye, for example, it is preferable to use a water-soluble dye typified by a direct dye, an acid dye, a basic dye, a reactive dye, and an edible dye. Coloring, sharpness,
Any dye may be used as long as it provides an image that satisfies stability, light resistance, and other required performance. As the pigment, for example, inorganic pigments such as carbon black, organic pigments, metal fine particles, metal oxides, and various metal compounds can be used.

The water-soluble dye is generally used by dissolving it in water or an aqueous solvent composed of water and an organic solvent, and particularly preferably a mixture of water and various water-soluble organic solvents. Is used, and the water content in the ink is from 20 to
It is preferable to use those prepared so as to be within the range of 90% by weight. As the water-soluble organic solvent used at this time, for example, carbon atoms such as methyl alcohol are 1 to 1
Alkyl alcohols, amides such as dimethylformamide, ketones or ketone alcohols such as acetone, ethers such as tetrahydrofuran, polyalkylene glycols such as polyethylene glycol, and alkylene groups such as ethylene glycol having 2 to 6 carbon atoms. Examples include alkylene glycols containing a number, lower alkyl ethers of polyhydric alcohols such as glycerin and ethylene glycol methyl ether, and the like.

Of these many water-soluble organic solvents,
Polyhydric alcohols such as diethylene glycol, and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether are preferred. The use of polyhydric alcohols is particularly preferable because it has a large effect as a lubricant for preventing nozzle clogging due to evaporation of water in the ink and precipitation of a water-soluble dye.

A solubilizing agent can be added to the ink. Typical solubilizers are nitrogen-containing heterocyclic ketones, the purpose of which is to significantly improve the solubility of a water-soluble dye in a solvent. For example, N-methyl-2-pyrrolidone, 1,3-dimethyl-
2-imidazolidinone is preferably used. Furthermore, the following additives can be added for use in improving the properties. For example, a viscosity adjusting agent, a surfactant, a surface tension adjusting agent, a pH adjusting agent, a specific resistance adjusting agent and the like can be added.

As a method of forming an image by applying the ink to the recording medium and performing recording, it is preferable to use an ink jet recording method. The recording method may be any method as long as the ink can be effectively released from the nozzles and applied to the recording medium. In particular, according to the method described in Japanese Patent Application Laid-Open No. 54-59936, ink subjected to the action of thermal energy causes a sudden change in volume, and the ink is ejected from a nozzle by the action force due to this state change. The method can be used effectively.

For printing on the recording medium of the present invention, the following 1. ~ 3. Can be used together. 1. 1. Ink using dye as color material 2. Ink using pigment as color material Ink containing a mixture of pigment colorant and dye colorant, or ink containing pigment colorant and dye colorant

When an image is formed on a recording medium of the present invention by using an ink using a dye as a coloring material, the solid printing of the multicolor ink is particularly preferred due to the high absorption capacity of the recording medium. Bleeding (boundary bleeding) in an image such as a combination is greatly reduced as compared with the related art. Furthermore,
The printed portion has significantly less whiteness and phenomena, the difference in gloss between the printed portion and the unprinted portion is small, and a natural photographic image can be obtained.
In addition, when a pigment is used as a coloring material, the pigment coloring material can be caught because the water-absorbing binder exists in the layer in addition to the gaps (voids) between the organic fine particles, and the rubbing property of the printed portion can be improved. Is high and the water resistance is good. Further, in the case where an ink in which a pigment coloring material and a dye coloring material are mixed is used, when recording is performed on a conventional recording medium, a difference occurs in the gloss between the printed portion of the pigment component and the printed portion of the dye component. However, when the recording medium of the present invention was used, the pigment component was fixed by both the void structure and the water-absorbing binder constituting the porous organic resin layer. The ink is uniformly distributed, and there is little difference in gloss due to the coloring material.

As the printing method, in addition to the conventional method, the following methods 1) to 3) can be used. 1) A method of printing inks having different types of color materials such as pigments and dyes in the same pixel 2) A method of printing three or more types of dark and light inks having different color material densities in the same pixel 3) The number of multi-pass passes High-speed printing method that applies a large amount of ink at a high density with one scan

Even when the recording medium of the present invention is printed with inks of different types of coloring materials such as pigments and dyes in the same pixel, for example, black ink is used as pigment ink, and other inks are used as dye inks. As a result, even when the print density of the black portion is to be increased and a sharp image is to be obtained, bleeding at the interface between the different types of ink is small, and there is a difference in gloss only in the portion where the image is formed by the black ink. Thus, a photographic image having a small difference in gloss due to a difference in color material can be obtained. Also, when printing three or more types of dark and light inks having different colorant densities in the same pixel, for example, by increasing the dot density and over-printing inks having different dye densities, shadows can be removed from the highlight part. Even if you want to express a smooth gradation over the part, using the recording medium of the present invention, the ink absorption capacity is high, and it is possible to print without overflowing the ink of the high density part,
Since the difference in gloss between the printed portion and the unprinted portion is small, the present invention can be applied to the formation of a fine image.

Further, the recording medium of the present invention can cope with a printing method in which a large number of inks are applied at a high density in one scan by reducing the number of multi-passes. That is, in recent years, there has been a demand for a recording medium capable of responding to an increase in printing speed.However, when the recording medium of the present invention is used, the number of passes is smaller than that of a conventional recording medium, and even when a large amount of ink is landed. In addition, it is possible to greatly reduce image quality deterioration due to ink overflow or bleeding. This is because, in the recording medium of the present invention, even when the amount of ink in each pass is large, the ink landed in the first pass is temporarily absorbed by the void structure, and the water-absorbing binder continues to absorb. For this reason, it is considered that a high ink absorbing ability enough to absorb the ink of the next pass can be maintained.

[0053]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Example 1 A recording medium having the structure shown in FIG. 1 was manufactured as follows. A PET film having transparency and a thickness of 100 μm (100Q8 manufactured by Toray Industries, Inc.) is formed on the base material 101.
0D) and a porous organic resin layer 102
In order to form a coating liquid, a coating liquid was prepared by the following method. As the organic fine particles, an aqueous dispersion of carboxymethyl cellulose nitrate having a nitric acid ester group as a hydrophobic group and a carboxymethyl group as a hydrophilic group obtained by the following method was used.

First, carboxymethyl cellulose was added to 40
g, sulfuric acid / nitric acid / water = 62.6 / 25.0 / 12.4
A mixed acid 400 cm ³ of a mixed, stirred, and the product separated and recovered by water washing, further, and then dried 1 hour at 100 ° C., to obtain a carboxymethyl cellulose nitrate. Next, the obtained carboxymethylcellulose nitrate, water, toluene, and an emulsifier were adjusted to a W / O state while stirring with a three-one motor, and water was further added to cause a phase transition to an O / W state. The organic solvent was removed with an evaporator to obtain an aqueous dispersion of organic fine particles. The average particle diameter of the organic fine particles was 142 nm, and Tg was 165 ° C. Further, the particles were scanned with a scanning electron microscope (Hitachi S-500).
Observation at 0) revealed that the surface was not a true sphere but an irregular shape with many irregularities on the surface.

The aqueous dispersion of the obtained organic fine particles was diluted with water so as to have a solid content of 10%, and a water-absorbing cationic urethane emulsion (water absorption 1.6 times, average particle diameter 50 n) was used.
The mixture was mixed at a mixing ratio of 10: 1 with m), and 25% aqueous ammonia was added at 3% by weight of the total amount for pH adjustment to obtain a coating liquid. The pH of the obtained coating solution was 6.0.

This coating solution was die-coated on a substrate using a coating machine and a hot-air drying furnace (not shown), and then dried (drying temperature: 120 ° C.) to form a porous organic resin layer 102 having a thickness of 30 μm.
Was formed. When the pore structure of the porous organic resin layer was observed on its surface and cross section with a scanning electron microscope (S-5000, manufactured by Hitachi, Ltd.), a pore structure having voids as shown in FIG. 2 was observed. . Further, when the maximum peak of the pore distribution curve of the porous organic resin layer was measured (Autosoap 1 manufactured by Kantachrome), the maximum peak was at a pore radius of 30 nm, and the pore volume was 0.252 cm ³ /. g, pH in the layer was 6.3.

Using the recording medium 100, the following evaluation was performed. Table 1 shows the evaluation results. In addition, the following evaluations (1) to (4) were performed, and as an overall evaluation, those having at least one x item were rejected, and those not having it were passed. (Evaluation) (1) Transparency The total light transmittance (%) of the recording medium was measured according to JIS K-71.
05, a haze meter (Nippon Denshoku Industries Co., Ltd.
DH-100DP).

(2) Tack and Fingerprint Resistance A finger touch test (holding the thumb for 10 seconds so that the thumb is in contact with the surface of the porous organic resin layer of the recording medium) was performed on the surface of the recording medium with bare hands. The presence or absence of adhesion and fingerprint marks was confirmed. The case where no fingerprint trace was confirmed was evaluated as ○, the case where some fingerprint trace was attached was evaluated as Δ, and the case where a finger adhered to the surface to form a fingerprint trace was evaluated as ×.

(3) Blocking property Ten recording media were stacked, placed in a PP bag, and placed at 30 ° C.
It was stored for one month in an environment of / 80% RH. After storage, those that could be separated without the recording media adhering to each other were evaluated as ○, and those that could not be separated were evaluated as x.

(4) Printing Characteristics An ink-jet printer that has a drop-on-demand ink-jet head having nozzles at a ratio of 24 lines per 1 mm (600 dpi) for each ink and scans the nozzle array in the vertical direction to form an image. The ink jet recording was performed by discharging 10 pl of ink per dot printing with the ink having the following composition. 1mm
24 × 24 dots per ² (600 dpi × 600 dpi
In the two-color printing using two single-color inks assuming that the ink amount in the printing of the single-color ink in i) is 100%, the ink amount is twice as large as that in the single-color printing.
Color and four-color printing were set to 300% and 400%, respectively.

As a color material of each color ink, C.I. I. Direct Yellow 86, M ink has C.I.
I. Acid Red 35 and C Ink are C.I. I. Direct Blue 199 and Bk Ink have C.I. I. Using the respective dyes of Food Black 2, the following three types of inks having different dye concentrations were prepared and used, respectively.

1) Ink composition 1: High-concentration dye ink ・ 3 parts of the above dye ・ 5 parts of diethylene glycol ・ 10 parts of polyethylene glycol ・ 82 parts of water

2) Ink composition 2: Concentration ink in dye ・ 1 part of the above dye ・ 5 parts of diethylene glycol ・ 10 parts of polyethylene glycol ・ 84 parts of water

3) Ink composition 3: Low-concentration dye ink 0.6 parts of the above dye 5 parts of diethylene glycol 10 parts of polyethylene glycol 84.4 parts of water

Using the above-prepared ink set consisting of four color inks of yellow (Y), magenta (M), cyan (C) and black (Bk), printing was performed on the recording medium of this embodiment. The following [1] to [7] regarding printing characteristics
Were evaluated for specific items.

[1] Presence / absence of bleeding, bleeding, beading, cissing, and unevenness Using the ink of the ink composition 1, using the recording apparatus,
The print ink amount of each color is from 100% (single color) to 400% (4
Color), and the presence or absence of bleeding, bleeding, beading, cissing, and streaks was visually observed, and evaluated according to the following criteria. Not generated at 400% printing ink amount: ず Not generated at 300% printing ink amount: ○ Not generated at 100% printing ink amount: △ Generated at 100% printing ink amount: ×

[2] Image Density The transmission image density of a solid printed image with the ink amount of each color of 100% (single color) was determined by using the above-described recording apparatus using each of the inks having a high dye concentration of ink composition 1, and X-Rite. Company 31
The measurement was performed using 0TR, and the image density was indicated by the obtained numerical value.

[3] Confirmation of Gradation Number Using the dark and light ink sets of ink compositions 1 to 3, printing was performed on the recording medium by controlling the ejection amount of each ink set in the recording apparatus. That is, printing was performed with a density change of about 60 steps, and each printed portion was visually observed. If a difference in image density could be determined, it was determined that gradation was obtained. The number of gradations when gradation was obtained by this method was counted.

[4] Confirmation of Color Reproducibility A solid pattern of a single color was printed at 100%, and color reproducibility (whether there was any abnormality in color) was visually checked for each of the four colors. Then, the case where the color was normal was evaluated as ○, and the case where the color was abnormal was evaluated as x.

[5] Ink Fixing Property A solid pattern was printed at 300%, and 10 sheets were continuously discharged at 1 sheet / minute. After printing, the presence or absence of sticking between the printed portion of the sheet and the back surface was checked. Then, a case where there was no sticking was evaluated as ○, and a case where there was sticking was evaluated as x.

[6] Water Resistance The solid pattern printed with each ink was printed 200%,
After leaving the ink to dry for 3 days, place the sheet in pure water for 3 days.
After immersion for a minute, it was confirmed whether the ink flowed out and the ink receiving layer was not melted. Then, those with no flow-out / melt are ○, those with flow-out / melt are ×
Was evaluated.

[7] OHP Transmissivity Projection was performed on a reflective overhead projector, and it was visually confirmed whether or not shadows (gray and yellow) on the sheet were conspicuous. And, when it is not conspicuous ○, when it is conspicuous ×
Was evaluated.

Comparative Example 1 A recording medium was obtained in the same manner as in Example 1, except that the binder was changed to water-soluble polyvinyl alcohol, and the pH was not adjusted. An image was formed on the obtained recording medium in the same manner as in Example 1, and the same items (1) to (4) were evaluated. Table 1 shows the evaluation results. The surface and cross section of the porous organic resin layer of this sheet were observed with a scanning electron microscope (S-5000, manufactured by Hitachi, Ltd.). As shown in FIG. 3, the pore structure was insufficient. Furthermore, when the maximum peak of the pore distribution curve of the porous organic resin layer was measured (measured by Autosoap 1 manufactured by Cantachrome Co.), the maximum peak was at a pore radius of 2 nm, and the pore volume was 0.052 cm. ³ / g, pH in the layer is 4.
It was 3.

Comparative Example 2 A recording medium was obtained in the same manner as in Example 1 except that organic fine particles were not contained (water-absorbing binder only). An image was formed on the obtained recording medium in the same manner as in Example 1, and the items (1) to (4) were similarly evaluated. Table 1 shows the evaluation results. When the surface and cross section of the ink receiving layer of this sheet were observed with a scanning electron microscope (S-5000, manufactured by Hitachi, Ltd.), no pore structure was observed as shown in FIG.

Comparative Example 3 A coating liquid was obtained in the same manner as in Example 1, except that alumina hydrate as porous inorganic particles was used instead of the organic fine particles, and the binder was polyvinyl alcohol. A recording medium was obtained by coating on the same substrate as in Example 1. An image was formed on the obtained recording medium in the same manner as in Example 1, and the items (1) to (4) were similarly evaluated. Table 1 shows the evaluation results.

In order to prepare a coating liquid, aluminum dodecoxide was first produced by the method described in US Pat. No. 4,242,271. Next, US Pat.
According to the method described in the specification of Japanese Patent No. 870, the aluminum dodecoxide was hydrolyzed to produce an alumina slurry. Water was added to the alumina slurry until the alumina hydrate solid content became 7.9%. The pH of this alumina slurry was 9.4. Next, a 3.9% nitric acid aqueous solution was added to adjust the pH, and then a maturing step was performed to obtain a colloidal sol. This colloidal sol is heated at an inlet temperature of 83 ° C.
To obtain an alumina hydrate powder having a boehmite structure. The alumina hydrate was dispersed in ion-exchanged water to form a 15% solution. Next, polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenol G)
H17) was dissolved in ion-exchanged water to obtain a 10% solution. The alumina hydrate and the polyvinyl alcohol solution were mixed and stirred at a weight mixing ratio of 7: 1 in terms of solid content to obtain a coating liquid.

The obtained coating liquid was die-coated on a base film using a coating machine and a hot-air drying furnace (not shown), and then dried at a drying temperature of 140 ° C. to form an ink receiving layer 102 having a thickness of 40 μm. . At this time, the maximum peak of the pore radius of the pore distribution curve of the ink receiving layer 102 was at 8.5 nm, and the pore volume was 0.54 cm ³ / g. The pH in the layer was 4.5. When the surface and cross section of the ink receiving layer of this sheet were observed with a scanning electron microscope (S-5000, manufactured by Hitachi, Ltd.), a pore structure as shown in FIG. 5 was found.

(Example 2) A recording medium was obtained in the same manner as in Example 1 except that the organic fine particles were changed to the following fine particles obtained by crosslinking acrylamide. An image was formed on the obtained recording medium in the same manner as in Example 1, and the items (1) to (4) were similarly evaluated. Table 1 shows the evaluation results.

The fine particles obtained by cross-linking acrylamide used in this example were produced as follows. First, acrylamide (60 parts by weight), methylenebisacrylamide (20 parts by weight as a crosslinking component), and methacrylic acid (20 parts by weight as a particle size adjusting component) were added and polymerized in ethanol to prepare an ethanol dispersion of organic fine particles. did. Next, pure water was added to the dispersion so that the mixing ratio of water: ethanol was 1: 1 and the mixture was sufficiently stirred with a stirrer. The average particle diameter of the organic fine particles thus obtained is 142 n.
m and Tg were 165 ° C. When the particles were observed with a scanning electron microscope (S-5000, manufactured by Hitachi, Ltd.), the particles were porous with fine pores formed on the surface. Furthermore,
When the porosity of the particles was measured by a nitrogen desorption adsorption method, it was 0.353 cm ³ / g.

Next, using the organic fine particles obtained above,
In the same manner as in Example 1, the mixture was mixed with a binder and stirred to obtain a coating liquid. Using this coating liquid, a recording medium was prepared in the same manner as in Example 1. When the surface and cross section of the porous organic resin layer of the obtained sheet were observed with a scanning electron microscope (S-5000, manufactured by Hitachi, Ltd.), a pore structure was confirmed. Furthermore, when the maximum peak of the pore distribution curve of the porous organic resin layer was measured (Autosoap 1 manufactured by Kantachrome),
The maximum peak was at a pore radius of 29 nm, the pore volume was 0.452 cm ³ / g, and the pH in the layer was 6.3.

[0081]

[Table 1]

(Embodiment 3) In this embodiment, an ink set made of a pigment ink containing a pigment as a coloring material of the ink is used.
An image was recorded on the recording medium obtained in Example 1.
The color material of each color ink used at this time is C.I. I. Pigment Yellow 83 and M ink have C.I.
I. Pigment Red 48: 3, C ink has C.I. I.
Pigment Blue 15: 3 and Bk inks were prepared using carbon black pigments and the following three inks having different colorant concentrations were prepared and used.

For the preparation of the pigment ink, first, a pigment dispersion having the following composition was prepared by a known dispersion method using the following dispersant, and thereafter, each color ink was prepared using the dispersion. -15 parts of the above pigment-Copolymer of polyethylene glycol monoacrylate having 45 mol of oxyethylene groups introduced therein and sodium acrylate [Molar ratio of monomers (former / latter) = 2/8] 3 parts-Monoethanolamine One copy

Using the above pigment dispersion, inks having different pigment concentrations as described below were prepared. <1> Ink composition 4: High-concentration pigment ink ・ Pigment dispersion liquid 33 parts ・ Diethylene glycol 4 parts ・ Ion exchange water 63 parts

<2> Ink composition 5: Ink concentration medium pigment 11 parts of pigment dispersion liquid 4 parts of diethylene glycol 85 parts of ion-exchanged water

<3> Ink composition 6: low-concentration pigment ink ・ 6.6 parts of pigment dispersion ・ 4 parts of diethylene glycol ・ 89.4 parts of ion-exchanged water Same as Example 1 using the above ink set (1) ~
The item (4) was evaluated. Further, the following items (5) and (6) were added. Table 2 shows the obtained evaluation results.

(5) Fixing property of color material Using the above-described recording apparatus, using a high-density ink of each color of the ink composition 4 prepared above, drying a solid printed portion with a print ink amount of 100% (single color), The coloring material was peeled off by rubbing with a finger. When the color material did not peel off, the evaluation was evaluated as ○, and when the color material peeled off, the evaluation was ×.

(6) Presence or Absence of Cracking in Solid Color Printing of Coloring Material Using the above-described recording apparatus, using the high-density ink of each color of the ink composition 4 prepared above, solid printing with a printing ink amount of 100% (monochrome). The thus-obtained portion was observed with an optical microscope (not shown) to confirm the presence or absence of cracks. Then, the case without cracks was evaluated as ○, and the case without cracks was evaluated as x.

Example 4 In this example, an image was formed on the same recording medium as in Example 1 by using both a pigment ink and a dye ink. At this time, an ink set including the dye ink prepared in Example 1 for Y, M, and C, and the pigment ink prepared in Example 3 for Bk, and an image was formed by the above-described recording apparatus. Then, evaluations (1) to (6) were performed in the same manner as in Example 3. (5),
In the evaluation of (6), an ink set of a combination of high density inks among the above inks was used. Table 2 shows the evaluation results.

Example 5 In this example, an image was recorded on the same recording medium as in Example 1 by using an ink set including the following inks having a color material in which a pigment and a dye were mixed. The same dye as used in Example 1 was used as the dye, and the pigment dispersion used in Example 3 was used as the pigment. [1] Ink composition 7: High-concentration dye / pigment mixed ink 1.5 parts of dye 16.5 parts of pigment dispersion liquid 4.5 parts of diethylene glycol 5 parts of polyethylene glycol 72.5 parts of water

[2] Ink Composition 8: Concentration Ink in Dye / Pigment Mixing Dye 0.5 parts Pigment dispersion 5.5 parts Diethylene glycol 4.5 parts Polyethylene glycol 5 parts Water 84.5 parts

[3] Ink composition 9: Dye / pigment mixed low-concentration ink Dye 0.3 part Pigment dispersion 3.3 parts Diethylene glycol 4.5 parts Polyethylene glycol 5 parts Water 86.9 parts

Then, as in Example 3, (1) to (6)
Was evaluated. In evaluations (5) and (6), an ink set composed of high-concentration inks of Bk, Y, M, and C of the pigment / dye ink was used. Table 2 shows the evaluation results.

(Comparative Example 4) In Example 3, Comparative Example 1
Example 3 An image was formed using the same recording medium as in Example 3.
In the same manner as in the above, the items (1) to (4) were evaluated. Table 1 shows the evaluation results. (Comparative Example 5) In Example 3, an image was formed using the same recording medium as in Comparative Example 3, and the items (1) to (4) were evaluated as in Example 3. Table 1 shows the evaluation results.

[0095]

[Table 2]

[0096]

As described above, according to the present invention, ink absorption speed is high, stickiness is prevented, transparency is high, fixing property of pigment ink and color reproducibility of dye ink are excellent, and When an image is formed thereon, the occurrence of cracks in the printing portion is prevented, the image density and the number of gradations are sufficient, and an image can be formed with excellent image water resistance and ink fixability. Provided are a recording medium, a manufacturing method thereof, and a recording method capable of performing good recording on the recording medium.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a recording medium of the present invention.

FIG. 2 is a schematic view of a view obtained by observing and photographing a porous organic resin layer of a recording medium of Example 1 with a scanning microscope.

FIG. 3 is a simulated view of a diagram obtained by observing and photographing a surface and a cross section of a recording medium of Comparative Example 1 with a scanning microscope.

FIG. 4 is a schematic diagram of a view in which a surface and a cross section of a recording medium of Comparative Example 4 are observed and photographed with a scanning microscope.

FIG. 5 is a schematic view of a diagram obtained by observing and photographing the surface and cross section of Comparative Example 3 with a scanning microscope.

[Explanation of symbols]

 100: Recording medium 101: Base material 102: Porous organic resin layer

Claims (17)

[Claims] 1. A recording medium in which at least one porous organic resin layer is formed on a base material, wherein the porous organic resin layer comprises organic fine particles having both a hydrophilic group and a hydrophobic group; It is formed from a binder and a void,
The pore distribution curve of the porous organic layer has a pore radius of 3 nm to 3 nm.
It has a maximum peak in the range of 00 nm and has a pore volume of 0.2 cm ³ / g or more.
PH in the porous organic resin layer measured according to the method described in No. 3 was 5.2.
A recording medium characterized by the above. 2. The recording medium according to claim 1, wherein the hydrophilic group is any one selected from the group consisting of a carboxyl group, a sulfone group, a hydroxyl group, a phosphonic acid group, an amino group, an amide group, and an ethyleneimine group. 3. The recording medium according to claim 1, wherein the hydrophobic group is any one selected from the group consisting of an ester group, an allyl group, a vinyl group and a propenyl group. 4. The organic fine particles have a glass transition temperature of 120 ° C.
The recording medium according to claim 1, wherein the temperature is in the range of -220C. 5. An organic fine particle having an average particle size of 5 nm to 30 nm.
The recording medium according to claim 1, wherein the recording medium is in a range of 0 nm. 6. The recording medium according to claim 1, wherein the organic fine particles are non-spherical. 7. The recording medium according to claim 1, wherein the organic fine particles have pores. 8. The recording medium according to claim 1, wherein the water-absorbing binder has cationic or nonionic properties. 9. The recording medium according to claim 1, wherein the substrate is a transparent substrate. 10. A method for producing a recording medium, comprising forming at least one or more porous organic resin layers on a base material,
JIS Z88 containing organic fine particles having both a hydrophilic group and a hydrophobic group, a water-absorbing binder, and a basic substance
An aqueous dispersion having a liquid pH of 5.2 or more as measured according to Example 02 is used as a coating liquid, and the coating liquid is coated on a substrate and dried to form a porous organic resin layer. A method for manufacturing a recording medium characterized by the above-mentioned. 11. The recording according to claim 10, wherein the organic fine particles are formed by being dispersed in a solvent by an emulsion polymerization method in which emulsion polymerization is performed using a nonionic emulsifier or a cationic emulsifier. The method of manufacturing the medium. 12. The method according to claim 10, wherein the water-absorbing binder is a resin emulsion. 13. The method according to claim 10, wherein the basic substance is any one selected from the group consisting of ammonia, tertiary ammonium salts, and quaternary ammonium salts. 14. An image forming method for forming an image by applying ink to a recording medium, wherein the recording medium is the recording medium according to any one of claims 1 to 9. Image forming method. 15. The image forming method according to claim 14, wherein an ink jet recording method is used for applying ink to the recording medium. 16. The image forming method according to claim 15, wherein the ink jet recording method is a method in which thermal energy is applied to ink to discharge ink droplets. 17. The image forming method according to claim 14, wherein an ink using a dye and / or a pigment as a coloring material is used.