JP2011073318A - Ink-jet recording medium and method for manufacturing the same - Google Patents

Abstract

To provide an ink jet recording medium having excellent image clarity, suppressing the occurrence of bronzing, and further capable of suppressing the occurrence of powder falling during cutting.
SOLUTION ink jet recording medium, on a base paper, has the effect of weakening the interfiber bonding force, after 1 g / ^{m 2} coating or size press base paper JAPAN TAPPI NO. A coating liquid containing a surface sizing agent in which the wax pick value measured at 1: 2000 is 1A or more lower than that before coating or size pressing and resin particles having ink solvent absorbability is applied or size pressed. Undercoat so that the total application amount of the surface sizing agent and the resin particles is 0.1 to 5.0 g / m ² , and the mass ratio of the surface sizing agent to the total application amount is 0.01 to 0.5. After providing the layer, a support obtained by smoothing with a calendar, and an ink image receiving layer provided on the support and containing inorganic fine particles having an average primary particle diameter of 30 nm or less are included.
[Selection figure] None

Description

  The present invention relates to an inkjet recording medium and a method for manufacturing the same.

  With the rapid development of the information technology industry, various information processing systems have been developed, and recording methods and recording apparatuses suitable for the information processing systems have been developed and put into practical use. Among these recording methods, the inkjet recording method is capable of recording on a variety of recording materials, has advantages such as being relatively inexpensive and compact in hardware (device), and excellent in quietness. It has also been widely used for so-called home use.

In addition, as the resolution of ink jet printers increases, so-called photo-like high-quality recorded materials can be obtained. With the advancement of such hardware (devices), various ink-jet recording media have been developed. It is coming.
In the use of photo glossy paper used for the purpose of obtaining such so-called photographic-like high-quality recorded matter, in addition to general properties such as ink absorbency, glossiness, surface smoothness, silver salt photography A similar photographic paper-like texture is also required.

In recent years, an ink jet recording medium having a porous structure in an ink receiving layer has been developed and put into practical use for the purpose of improving the various properties described above. Such an ink jet recording medium has a porous structure, is excellent in ink receptivity (fast drying property), and has high gloss.
As a support constituting an ink jet recording medium having such an ink receiving layer, a support having an undercoat layer formed by adhering a composition containing thermoplastic resin particles on a paper substrate is known, and an ink is known. It is said that the occurrence of cockling during the formation of the receiving layer can be suppressed (for example, see Patent Document 1). Further, a support for an image recording material in which a softening agent is added to the surface of a base paper is known, and is said to be excellent in flatness and rigidity (for example, see Patent Document 2).

JP 2005-238829 A JP 2005-154996 A

However, when an inkjet recording medium is configured using the recording medium support described in Patent Documents 1 and 2, it is sufficient in terms of image clarity, suppression of bronzing, and further suppression of powder falling during cutting. It was hard to say.
An object of the present invention is to provide an ink jet recording medium that has excellent image clarity, suppresses the occurrence of bronzing, and further suppresses the occurrence of powder falling off during cutting, and a method for manufacturing the same.

Specific means for solving the above-mentioned problems are as follows.
<1> A support having an undercoat layer provided on at least one side of a base paper, and an ink receiving layer provided on the undercoat layer. The support is coated with 1 g / m ^{2 on the} base paper or a size press. After Japan TAPPI NO. A surface sizing agent in which a wax pick value measured in accordance with 1: 2000 is 1 A or more lower than that before the application or size pressing, and a coating liquid containing resin particles having ink solvent absorptivity, The surface sizing agent is applied to at least one side of the base paper by application or a size press, and the total application amount of the surface sizing agent and the resin particles is 0.1 to 5.0 g / m ² , and the surface sizing agent is added to the total application amount. A support obtained by applying a smoothing treatment with a calendar after providing an undercoat layer so that the mass ratio is 0.01 to 0.5, and the ink receiving layer has an average primary particle size of 30 nm or less. An ink jet recording medium containing inorganic fine particles.
<2> The surface sizing agent is an alkyl ester resin, an alkyl ether resin, an alkylamide, an alkyl ketene dimer, an amino ammonium salt, a fatty acid-containing compound having 10 to 30 carbon atoms, a fatty acid polyamide polyamine, or a fatty acid polyamide polyamine epichlorohydrin condensation. A fatty acid diamide diamine, a fatty acid monoamide, a polyalkylene polyamine fatty acid epichlorohydrin condensate, an epoxidized fatty acid amide, a fatty acid diamide salt, an alkylene oxide adduct of a fatty acid ester, and a fatty acid quaternary ammonium salt. The inkjet recording medium according to <1>, which is a seed.
<3> The resin particles are selected from the group consisting of acrylic resins, acrylic silicon resins, acrylic epoxy resins, acrylic urethane resins, styrene-butadiene resins, acrylonitrile-butadiene resins, and vinyl acetate resins. The inkjet recording medium according to <1> or <2>, wherein the inkjet recording medium is at least one kind.
<4> The inkjet recording medium according to any one of <1> to <3>, wherein the resin particles have a glass transition temperature (Tg) of −10 ° C. to 85 ° C.
<5> The inorganic fine particles according to any one of <1> to <4>, wherein the inorganic fine particles are at least one selected from the group consisting of vapor-phase process silica, colloidal silica, and alumina hydrate. Inkjet recording medium.
<6> The ink receiving layer includes a layer containing gas phase method silica having an average primary particle size of 10 nm or less, polyvinyl alcohol, a crosslinking agent, an organic mordant, and a water-soluble polyvalent metal salt. The inkjet recording medium according to any one of <1> to <5>, wherein the total mass is 15 g / m ² or less.
<7> The <1> to <6>, wherein the undercoat layer further includes at least one of an inorganic pigment and an optical brightener, and the density of the support is 0.7 to 1.15 g / cm ^3. The inkjet recording medium according to any one of the above.

<8> A method for producing an ink jet recording medium having an undercoat layer and an ink receiving layer on at least one side of a base paper, wherein 1 g / m ^{2 is} applied or size-pressed on the base paper, followed by JAPAN TAPPI NO. A surface sizing agent in which a wax pick value measured in accordance with 1: 2000 is 1 A or more lower than that before the application or size pressing, and a coating liquid containing resin particles having ink solvent absorptivity, The surface sizing agent is applied to at least one side of the base paper by application or a size press, and the total application amount of the surface sizing agent and the resin particles is 0.1 to 5.0 g / m ² , and the surface sizing agent is added to the total application amount. A step of providing an undercoat layer such that the mass ratio is 0.01 to 0.5, a step of obtaining a support by subjecting the base paper provided with the undercoat layer to a smoothing process using a calendar, and a step on the support. And a step of providing an ink receiving layer containing inorganic fine particles having an average primary particle diameter of 30 nm or less.
<9> The smoothing treatment by the calendar is performed using a calendar having a nip width of 50 mm or more and a metal roll or a steel belt, and a surface temperature of the metal roll or the steel belt is set to 110 ° C. or more <8> 2. A method for producing an ink jet recording medium according to 1.
<10> The method for producing an inkjet recording medium according to <8> or <9>, wherein the smoothing process using the calendar is performed using a calendar including a steel belt.
<11> The step of providing the ink receiving layer is performed by applying a coating solution containing vapor phase silica having an average primary particle size of 10 nm or less, polyvinyl alcohol, a crosslinking agent, an organic mordant, and a water-soluble polyvalent metal salt to a solid content. a method for producing an ink jet recording medium according to any one of the <8> - <10> the amount comprising the step of applying to a 15 g / m ² or less.
<12> The step of providing the undercoat layer includes the step of applying or size pressing a coating liquid containing at least one of the resin particles, the surface sizing agent, and an inorganic pigment and a fluorescent brightening agent. The manufacturing method of the inkjet recording medium of any one of>-<11>.

  According to the present invention, it is possible to provide an ink jet recording medium that has excellent image clarity, suppresses the occurrence of bronzing, and further suppresses the occurrence of powder falling during the cutting process, and a method for manufacturing the same.

The ink jet recording medium of the present invention includes a support having an undercoat layer provided on at least one side of a base paper, and an ink receiving layer provided on the undercoat layer. The support is coated with JAPAN TAPPI No. 1 after applying or size pressing 1 g / m ^{2 on the} base paper. A coating liquid containing a surface sizing agent in which a wax pick value measured in accordance with 1: 2000 is 1 A or more lower than that before the application or size pressing, and resin particles having ink solvent absorbability is used as a base paper. The surface sizing agent is applied to at least one surface by a size press, the total application amount of the surface sizing agent and the resin particles is 0.1 to 5.0 g / m ² , and the mass of the surface sizing agent with respect to the total application amount The support is obtained by providing a primer layer so as to have a ratio of 0.01 to 0.5 and then smoothing with a calendar. The ink receiving layer is an inorganic material having an average primary particle size of 30 nm or less. It contains fine particles.
By configuring the ink jet recording medium using the support having such a specific configuration, it has excellent image clarity, the occurrence of bronzing is suppressed, and the occurrence of powder falling during cutting is further suppressed.

[Support]
The support in the present invention is prepared by applying JAPAN TAPPI NO. After applying 1 g / m ^{2 to the} base paper or pressing it on at least one side of the base paper. A surface sizing agent in which the wax pick value measured in accordance with 1: 2000 is 1A or more lower than that before the coating or size pressing (hereinafter referred to as “surface sizing agent having an action of weakening interfiber bonding force”). And a coating liquid containing resin particles having ink solvent absorbability is applied or size-pressed to provide an undercoat layer, and then smoothed by a calendar, and is obtained. .
Since the support having such a configuration has high flatness and excellent ink absorbability, excellent image clarity and suppression of bronzing are possible when an ink jet recording medium is configured. In addition, the occurrence of cockling when forming the ink receiving layer can be suppressed. Furthermore, since the adhesiveness between the support and the ink receiving layer is good, it is possible to effectively suppress the occurrence of powder falling during the cutting process.

(Base paper)
The base paper is preferably made of wood pulp as a main raw material, and if necessary, paper made using synthetic pulp such as polypropylene or synthetic fibers such as nylon or polyester in addition to wood pulp. As the above-mentioned wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, NUKP can be used, but more LBKP, NBSP, LBSP, NDP, LDP with more short fibers are used. preferable.
However, the ratio of LBSP and / or LDP is preferably 10% by mass or more and 70% by mass or less.

  The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also useful.

  In the base paper, higher fatty acids, internal sizing agents such as alkyl ketene dimers, white inorganic pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancers such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, Water retaining agents such as polyethylene glycols, dispersants, softening agents such as quaternary ammonium, and the like can be appropriately added.

  The freeness of pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the fiber length after beating is 24% by weight as defined in JIS P-8207, and 42 mesh remaining. The sum of the mass% of the minute is preferably 30 to 70%. In addition, it is preferable that the mass% of 4 mesh remainder is 20 mass% or less.

The basis weight of the base paper is preferably 30 to 250 g / ^{m 2,} especially 50 to 200 g / ^{m 2} is preferred. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by calendering at the paper making stage or after paper making. The density of the base paper is preferably 0.7 to 1.1 g / cm ³ (JIS P-8118).
Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P-8143.

  The pH of the base paper is preferably 5 to 9 when measured by the hot water extraction method defined in JIS P-8113.

(Surface sizing agent)
As the surface sizing agent in the present invention, a surface sizing agent having an action of weakening the interfiber bonding force is used. Specifically, the action of weakening the fiber-to-fiber bonding force mentioned here is that after applying the surface sizing agent to the base paper in an application amount of 1 g / m ² or by applying a size press, JAPAN TAPPI NO. It means that the wax pick value measured according to the rule of 1: 2000 is reduced by 1 A or more as compared with that before the coating or size pressing. In the present invention, from the viewpoint of image clarity and cockling, the decrease in the wax pick value is preferably 2A or more.

  The surface sizing agent having an action of weakening the interfiber bonding force generally includes chemicals known as softening agents, softening agents, bulking agents and the like. Specifically, alkyl ester resins, alkyl ether resins, alkyl amides, alkyl ketene dimers, aminoammonium salts, fatty acid-containing compounds having 10 to 30 carbon atoms, fatty acid polyamide polyamines, fatty acid polyamide polyamine epichlorohydrin condensates, fatty acid diamides Diamine, fatty acid monoamide, fatty acid diamide, polyalkylene polyamine fatty acid epichlorohydrin condensate, epoxidized fatty acid amide, fatty acid diamide salt, polyhydric alcohol and fatty acid ester compound, polyhydric alcohol and fatty acid ester compound ethylene oxide adduct, higher alcohol Ethylene and / or propylene oxide adducts, polyhydric alcohol type nonionic surfactants, higher fatty acid ethylene oxide adducts, fatty acid ester alkylene Kisaido adducts, and it can include at least one selected from the group consisting of fatty quaternary ammonium salts.

  Among them, from the viewpoint of powder fall prevention and image clarity, alkyl ester resins, alkyl ether resins, alkylamides, alkyl ketene dimers, aminoammonium salts, fatty acid-containing compounds having 10 to 30 carbon atoms, fatty acid polyamide polyamines, fatty acid polyamides From the group consisting of polyamine epichlorohydrin condensate, fatty acid diamide diamine, fatty acid monoamide, fatty acid diamide, polyalkylene polyamine fatty acid epichlorohydrin condensate, epoxidized fatty acid amide, fatty acid diamide salt, alkylene oxide adduct of fatty acid ester, and fatty acid quaternary ammonium salt Preferably, at least one selected from alkyl ketene dimers, fatty acid monoamides, fatty acid diamides, epoxidized fatty acid amides, fatty acid diamide salts, fatty acid esters. More preferably, it is at least one selected from an alkylene oxide adduct of tellurium and a fatty acid quaternary ammonium salt, from an alkyl ketene dimer, a fatty acid monoamide, a fatty acid diamide, an epoxidized fatty acid amide, and an alkylene oxide adduct of a fatty acid ester. More preferably, it is at least one selected.

(Resin particles)
The resin particles in the present invention are characterized by having ink solvent absorbability. Thereby, when an ink jet recording medium is configured, the ink absorption speed is improved, and the occurrence of bronzing can be effectively suppressed. Further, the occurrence of cockling during the formation of the ink receiving layer can be effectively suppressed.
Here, the resin particles have ink solvent absorptivity, for example, when a coating film made of resin particles is formed on the base paper, a solvent commonly used for ink jet inks, such as glycerin and 2-pyrrolidone. It means that an absorptive coating film can be formed with respect to an aqueous solution containing 5 to 30% by mass of at least one of isopropyl alcohol, ethylene glycol, diethylene glycol, diethylene glycol monobutyl ether and the like.

Specifically, the Cobb water absorption test (contact) defined in JIS P8140 using a 15% aqueous solution of diethylene glycol monobutyl ether after applying resin particles on the base paper to a solid content of 2 g / m ² and drying. The measured value of (time 2 minutes) is 10 g / m ² or more. In the present invention, the measured value of the Cobb water absorption test is preferably 10 g / m ² or more and 250 g / m ² or less, more preferably 15 g / m ² or more and 200 g / m ² or less. .

The resin particles are preferably in the form of water-dispersible latex from the viewpoint of productivity.
Specific examples of resin particles having ink solvent absorbability used in the undercoat layer of the present invention include acrylic resins, acrylic silicon resins, acrylic epoxy resins, acrylic styrene resins, acrylic urethane resins, styrene-butadienes. Resin, acrylonitrile-butadiene resin, vinyl acetate resin, methacrylic resin, styrene resin, styrene copolymer resin, natural rubber resin, nitrile-butadiene resin, and the like.
Among these, from the viewpoint of image clarity, bronzing suppression, and powder-off suppression during cutting, acrylic resin, acrylic silicon resin, acrylic epoxy resin, acrylic urethane resin, styrene-butadiene resin, acrylonitrile-butadiene resin, And at least one selected from the group consisting of vinyl acetate resins, and at least one selected from the group consisting of acrylic resins, styrene-butadiene resins, acrylic silicon resins, and acrylic urethane resins. More preferably, it is at least one selected from the group consisting of acrylic resins, styrene-butadiene resins, and acrylic urethane resins.

  Furthermore, the glass transition temperature (Tg) of the resin particles is preferably −10 ° C. to 85 ° C., more preferably −5 ° C. to 80 ° C., and further preferably 0 ° C. to 70 ° C. When Tg is 85 ° C. or lower, the image clarity is more effectively improved, and the occurrence of powder falling off when cutting is more effectively suppressed. Moreover, generation | occurrence | production of cockling and bronzing can be suppressed more effectively because Tg is -10 degreeC or more.

The undercoat layer in the present invention is provided by applying a coating liquid containing at least one kind of the surface sizing agent and at least one kind of the resin particles to at least one side of the base paper by coating or a size press.
Furthermore, in the present invention, the total application amount of the surface sizing agent and the resin particles is 0.1 to 5.0 g / m ² , and the surface with respect to the total application amount of the surface sizing agent and the resin particles. The mass ratio of the sizing agent (surface sizing agent / (surface sizing agent + resin particles)) is 0.01 to 0.5.
When the total application amount of the surface sizing agent and the resin particles is less than 0.1 g / m ² , cockling may occur, image clarity may deteriorate, or a sufficient bronzing suppression effect may not be obtained. . If the total applied amount exceeds 5.0 g / m ² , the productivity may decrease.
If the mass ratio of the surface sizing agent to the total amount of the surface sizing agent and the resin particles is less than 0.01, cockling and image clarity may not be sufficiently suppressed. On the other hand, if it exceeds 0.5, the powder fall-off suppressing effect during cutting may be reduced.

In the present invention, the total application amount of the surface sizing agent and the resin particles in the undercoat layer is preferably 0.15 to 5.0 g / m ² from the viewpoint of cockling suppression, image clarity, and bronzing suppression. 0.2 to 5.0 g / m ² is more preferable.
In addition, the mass ratio of the surface sizing agent to the total amount of the surface sizing agent and the resin particles is 0.01 to 0.45 from the viewpoints of powder fall-off suppression during cutting, image clarity, and cockling. Preferably, it is 0.01-0.4.

Furthermore, in the present invention, from the viewpoints of powder fall-off suppression at the time of cutting, image clarity, and bronzing suppression, the total application amount of the surface sizing agent and the resin particles in the undercoat layer is 0.15 to 5.0 g / m ^2. The mass ratio of the surface sizing agent to the total application amount is preferably 0.01 to 0.45, and the total application amount of the surface sizing agent and the resin particles is 0.2 to 5.0 g. a / ^{m 2,} the weight ratio of said surface size to said total application amount is more preferably 0.01 to 0.4.

  In the present invention, the coating liquid for forming the undercoat layer contains at least one kind of the surface sizing agent and at least one kind of the resin particles, but may contain other components as necessary. Examples of other components include inorganic pigments and fluorescent brighteners. In the present invention, from the viewpoint of image clarity and suppression of bronzing, it is preferable to include at least one of an inorganic pigment and a fluorescent brightening agent.

As the inorganic pigment, a commonly used inorganic pigment can be used without particular limitation. For example, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous White inorganic pigments such as porous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrous halloysite, magnesium carbonate, magnesium hydroxide.
As the fluorescent brightening agent, a commonly used fluorescent brightening agent can be used without particular limitation. For example, K.K. The compounds described in Vene-Ratarammann, “The Chemistry of Synthetic Dies”, Volume V, Chapter 8, can be used. More specifically, stilbene compounds, coumarin compounds, biphenyl compounds, benzoxazolyl compounds, naphthalimide compounds, pyrazoline compounds, carbostyril compounds, and the like can be given.

In the present invention, the coating liquid for forming the undercoat layer is applied on the base paper by coating or size pressing. As a method for applying the coating liquid, a commonly used application method can be used without any particular limitation. Specifically, for example, a known coating apparatus such as an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or a bar coater can be used.
The size press can be performed by a known size press method represented by a horizontal size press method, a roll coater method, a calendar size press method and the like.

Furthermore, the support in the present invention is obtained by providing the undercoat layer on a base paper and then smoothing it using a calendar. As the calendar, a calendar that is generally used in papermaking and coating processes can be used without particular limitation. Specific examples include a soft calender composed of a combination of a metal roll and a synthetic resin roll, and a long nip shoe calender composed of a metal roll and a shoe roll via a synthetic resin belt or a steel belt.
Among them, a calender having a nip width of 50 mm or more is preferable from the viewpoint of more suitably demonstrating the effects of the present invention. A calender is more preferable, and a long nip shoe calender consisting of a metal roll and a shoe roll via a steel belt and having a nip width of 50 mm or more is further preferable.

In the present invention, the surface temperature of the metal roll or steel belt is preferably 110 ° C. or higher, and more preferably 120 ° C. or higher, from the viewpoint of image clarity and suppression of bronzing. The upper limit of the surface temperature is not particularly limited and can be appropriately selected according to the purpose. For example, about 300 ° C. is preferable.
In addition, the nip pressure in the smoothing process using the calendar is not particularly limited and can be appropriately selected depending on the purpose. For example, the nip linear pressure is preferably 500 kN / m or less, and more preferably 300 kN / m or less.

Further, the density of the support is not particularly limited, but is preferably 0.7 to 1.15 g / cm ^{3, and} preferably 0.75 to 1.15 g / cm ³ from the viewpoint of image clarity and handleability. It is more preferable that it is 0.8 to 1.15 g / cm ³ .

A back coat layer can be provided on the support, and examples of components that can be added to the back coat layer include a white pigment, an aqueous binder, and other components.
Examples of white pigments contained in the backcoat layer include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, and aluminum silicate. , Diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrous halloysite, magnesium carbonate, magnesium hydroxide, white inorganic pigment, styrene And organic pigments such as polyethylene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins, and melamine resins.

Examples of the aqueous binder used in the back coat layer include styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxy Examples thereof include water-soluble polymers such as methyl cellulose, hydroxyethyl cellulose, and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion.
Examples of other components contained in the backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water-proofing agent.

  The ink jet recording medium of the present invention is characterized by having the support and an ink receiving layer provided on the support. With such a configuration, it is possible to configure an ink jet recording medium that is excellent in image clarity and ink absorbability and in which the occurrence of cockling and bronzing is suppressed. In addition, such an ink jet recording medium is excellent in processability because the occurrence of powder falling during cutting is suppressed.

[Ink receiving layer]
The ink receiving layer in the invention includes at least one inorganic fine particle having an average primary particle size of 30 nm or less, and further includes a water-soluble resin, a cationic polymer, a polyvalent metal salt, and the like as necessary.
The ink receiving layer in the present invention may be composed of only one layer or may be composed of two or more layers.

(Inorganic fine particles)
The inorganic fine particles form a porous structure when the ink receiving layer is formed, and have a role of improving ink absorption performance.
In particular, if the solid content of the inorganic fine particles in the ink receiving layer is 50% by mass or more, more preferably more than 60% by mass, it is possible to form a more favorable porous structure, and sufficient ink absorption. This is preferable because an ink jet recording medium having the properties can be obtained. Here, the solid content in the ink receiving layer of fine particles is a content calculated based on components other than water in the composition constituting the ink receiving layer.

Examples of the inorganic fine particles in the present invention include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, pseudoboehmite, zinc oxide. Zinc hydroxide, alumina, aluminum silicate, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, yttrium oxide and the like. Among these, silica fine particles, colloidal silica, alumina fine particles, or pseudoboehmite are preferable from the viewpoint of forming a good porous structure. The fine particles may be used as primary particles or in a state where secondary particles are formed.
In the present invention, the average primary particle size of the inorganic fine particles is 30 nm or less, preferably 20 nm or less, and more preferably 10 nm or less.
Further, the inorganic fine particles include silica fine particles having an average primary particle size of 30 nm or less, colloidal silica having an average primary particle size of 30 nm or less, alumina fine particles having an average primary particle size of 20 nm or less, and pseudoboehmite having an average pore radius of 2 to 15 nm. In particular, silica fine particles having an average primary particle size of 10 nm or less are preferred.

  Silica fine particles are generally roughly classified into wet method particles and dry method (gas phase method) particles according to the production method. In the above wet method, a method is mainly used in which activated silica is produced by acid decomposition of a silicate, and this is appropriately polymerized and agglomerated and precipitated to obtain hydrous silica. On the other hand, the gas phase method is a method by high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized with air. A method of obtaining anhydrous silica by the (arc method) is the mainstream, and “gas phase method silica” means silica (anhydrous silica fine particles) synthesized by the gas phase method. As the silica fine particles used in the present invention, gas phase method silica fine particles are particularly preferable.

The gas phase method silica is different from hydrous silica in terms of the density of silanol groups on the surface, the presence or absence of vacancies, etc., and exhibits different properties, but is suitable for forming a three-dimensional structure with a high porosity. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is high at 5 to 8 / nm ² , and the silica fine particles tend to aggregate closely (aggregate). In the case of the method silica, the density of silanol groups on the surface of the fine particles is 2 to 3 / nm ² , so that it is sparse soft aggregation (flocculate), and as a result, it is assumed that the structure has a high porosity. Is done.

  The above-mentioned vapor phase silica has a particularly large specific surface area, so the ink absorption and retention efficiency is high, and the refractive index is low. Therefore, if the dispersion is made to an appropriate particle size, transparency can be imparted to the receiving layer. It is characterized by high color density and good color development. The transparency of the receiving layer is not only for applications that require transparency, such as OHP, but also in terms of obtaining high color density and good color development gloss even when applied to recording media such as photo glossy paper. is important.

  The average primary particle diameter of the vapor phase silica is preferably 30 nm or less, more preferably 20 nm or less, particularly preferably 10 nm or less, and most preferably 3 to 10 nm. Since the vapor phase silica is easily adhered to each other by hydrogen bonding with a silanol group, a structure having a large porosity can be formed when the average primary particle diameter is 30 nm or less, and ink absorption characteristics are effectively improved. Can be improved.

  Silica fine particles may be used in combination with the other fine particles described above. When the other fine particles and the vapor phase silica are used in combination, the content of the vapor phase silica in all the fine particles is preferably 30% by mass or more, and more preferably 50% by mass or more.

As the inorganic fine particles in the present invention, alumina fine particles, alumina hydrate, a mixture or a composite thereof are also preferable. Of these, alumina hydrate is preferable because it absorbs and fixes ink well, and pseudoboehmite (Al ₂ O ₃ .nH ₂ O) is particularly preferable. Alumina hydrates can be used in various forms, but it is preferable to use sol boehmite as a raw material because a smooth layer can be easily obtained.

About the pore structure of pseudo boehmite, the average pore radius is preferably 1 to 30 nm, and more preferably 2 to 15 nm. The pore volume is preferably 0.3 to 2.0 ml / g, more preferably 0.5 to 1.5 ml / g. Here, the pore radius and pore volume are measured by a nitrogen adsorption / desorption method, and can be measured by, for example, a gas adsorption / desorption analyzer (for example, trade name “Omni Soap 369” manufactured by Coulter). .
Among the alumina fine particles, vapor phase method alumina fine particles are preferable because of their large specific surface area. The average primary particle size of the vapor phase alumina is preferably 30 nm or less, and more preferably 20 nm or less.

  When the above-mentioned fine particles are used in an ink jet recording medium, for example, JP-A-10-81064, JP-A-10-119423, JP-A-10-157277, JP-A-10-217601, JP-A-11-348409, JP-A-2001-138621. No. 2000-43401 No. 2000-2111235 No. 2000-309157 No. 2001-96897 No. 2001-138627 No. 11-91242 No. 8-2087 No. 8-2090 No. 8-2091, 8-2093, 8-174992, 11-192777, JP-A-2001-301314, and the like can also be preferably used.

(Colloidal silica)
In the present invention, it is also preferable to provide a colloidal silica layer as the uppermost layer of the ink receiving layer. When the ink receiving layer in the present invention has a colloidal silica layer as the uppermost layer, the average primary particle size of the colloidal silica used is preferably 10 nm to 200 nm, more preferably 50 nm to 150 nm.
In addition, the colloidal silica in the present invention is preferably anionic and nonionic. An anionic property is particularly preferable. The ^{content, 0.01g / m 2 ~5g / m} 2 is preferred. 0.05 g / m ² to ² g / m ² is particularly preferable.

(Nitrogen-containing organic cationic polymer)
The ink receiving layer in the invention preferably contains at least one nitrogen-containing organic cationic polymer from the viewpoint of suppressing bleeding of the recorded image and from the viewpoint of dispersing silica.
The nitrogen-containing organic cationic polymer in the present invention is not particularly limited, but a polymer having a primary to tertiary amino group or a quaternary ammonium base is preferable.
The nitrogen-containing organic cation polymer is a nitrogen-containing organic cation which is a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof or a quaternary ammonium base (nitrogen-containing organic cation monomer). Conjugated dienes such as polymers, nitrogen-containing organic cationic polymers obtained as a copolymer or condensation polymer of the nitrogen-containing organic cationic monomer and other monomers, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer Acrylic polymers such as polymers or copolymers of acrylic acid esters and methacrylic acid esters, polymers or copolymers of acrylic acid and methacrylic acid; styrene-acrylic acid ester copolymers, styrene- Styrene-acrylic polymers such as methacrylate copolymers; ethylene vinyl acetate copolymer Vinyl polymer and the like; the urethane polymer or the like having a urethane bond include a nitrogen-containing organic cation polymers obtained by cationizing modified with a compound containing a cationic group.

  Examples of the nitrogen-containing organic cation monomer include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N, N -Dimethyl-N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-Np -Vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N- Ethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-N -P-vinylbenzylammonium chloride;

Trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl-m-vinyl Benzylammonium acetate, N, N, N-triethyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N, N-triethyl-N-2- (3-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride Tate;

N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N- Methyl chloride, ethyl chloride, methyl bromide of dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide , Quaternary compounds with ethyl bromide, methyl iodide or ethyl iodide, or sulfonates, alkyl sulfonates, acetates or alkyl carboxylates substituted with anions thereof.

  Specific examples of the compound include monomethyl diallylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, Triethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl- 2- (methacryloylamino) ethylammonium chloride, trimethyl-2- (acryloylua) C) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) Propylammonium chloride, triethyl-3- (acryloylamino) propylammonium chloride;

N, N-dimethyl-N-ethyl-2- (methacryloyloxy) ethylammonium chloride, N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N, N-dimethyl-N-ethyl- 3- (acryloylamino) propylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, trimethyl-3- And (acryloylamino) propylammonium acetate. In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole. In addition, a polymerization unit such as N-vinylacetamide, N-vinylformamide or the like, which is converted into a vinylamine unit by hydrolysis after polymerization, and a salt thereof can be used.

  Examples of the other monomer that can be copolymerized (or polycondensed) with the nitrogen-containing organic cation monomer include primary to tertiary amino groups and salts thereof, or basic such as a quaternary ammonium base. Or the monomer which does not contain a cationic part, does not show interaction with the dye in an inkjet ink, or is substantially small interaction is mentioned. For example, (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylic acid; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; benzyl (meth) acrylic acid Aralkyl esters of styrene; aromatic vinyls such as styrene, vinyl toluene and α-methyl styrene; vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate; allyl esters such as allyl acetate; vinylidene chloride, vinyl chloride, etc. A halogenated monomer such as: (c) vinyl cyanide such as (meth) acrylonitrile; and olefins such as ethylene and propylene.

  The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl moiety, specifically, for example, methyl (meth) acrylate or ethyl (meth) acrylate. Propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, (meth) Examples include octyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like. Among these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and hydroxyethyl methacrylate are preferable. The other monomers can also be used alone or in combination of two or more.

  Moreover, as a monomer which comprises a urethane type polymer, the polyvalent isocyanate compound (For example, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, m-phenylene diisocyanate, 4,4 which has two or more isocyanate groups). '-Diphenylmethane diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatemethyl) -cyclohexane, 1,5-diisocyanate-2-methylpentane, hydrogenated Xylylene diisocyanate, hydrogenated 4,4′-diphenylmethane diisocyanate, etc.) and a compound that can react with an isocyanate group to form a urethane bond (eg, glycerin) Polyol compounds such as 1,6-hexanediol, triethanolamine, polypropylene glycol, polyethylene glycol, bisphenol A, hydroquinone; succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1 , 3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalene Acid, biphenylcarboxylic acid, sorbitol, sucrose, aconitic acid, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, propylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, Such as hydroxybenzoic acid, hydroxyphthalic acid, 1,2,3-propanetrithiol, ethylenediamine, propylenediamine, hexamethylenediamine, phenylenediamine, tolylenediamine, diphenyldiamine, diaminodiphenylmethane, diaminocyclohexylmethane, piperazine, isophoronediamine Such diamines; and hydrazine).

  Furthermore, examples of the compound that introduces a cationic group into a copolymer or condensate having no cationic group include alkyl halides and methylsulfuric acid.

Among the nitrogen-containing organic cationic polymers described above, from the viewpoint of suppressing bleeding, cationic polyurethanes and cationic polyacrylates described in JP-A No. 2004-167784 are preferable, and cationic polyurethanes are more preferable.
Examples of commercial products of cationic polyurethane include “Superflex 650”, “F-8564D”, “F-8570D” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., “Neofix IJ-150” manufactured by Nikka Chemical Co., Ltd. Or the like.

Further, from the viewpoint of dispersion of inorganic fine particles, polydiallyldimethylammonium chloride and polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride derivatives are preferable, and polydiallyldimethylammonium chloride is more preferable.
Examples of commercially available products include “Charol DC902P” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

Further, these nitrogen-containing organic cationic polymers can be used in any form of a water-soluble polymer, water-dispersible latex particles, and an aqueous emulsion.
Examples of the aqueous emulsion include conjugated diene copolymer emulsions; acrylic polymer emulsions; styrene-acrylic polymer emulsions; vinyl polymer emulsions; urethane emulsions and the like that are cationized using a compound having a cationic group. And those obtained by cationizing the emulsion surface with a cationic surfactant, polymerized under cationic polyvinyl alcohol, and distributing the polyvinyl alcohol on the emulsion surface. Among these cationic emulsions, a cationic polyurethane emulsion whose main component is a urethane emulsion is preferable.

  In the present invention, the nitrogen-containing organic cationic polymer contained in the first coating solution is preferably a cationic polyurethane, more preferably a cationic polyurethane emulsion, from the viewpoint of suppressing bleeding.

  In the present invention, the content of the nitrogen-containing organic cationic polymer contained in the ink receiving layer can be, for example, 0.1 to 10% by mass with respect to the inorganic fine particles from the viewpoint of image quality to be formed. It is preferable that it is 0.5-8 mass%.

(Water-soluble aluminum compound)
The ink receiving layer in the invention preferably contains at least one water-soluble aluminum compound.
As a water-soluble aluminum compound, for example, as an inorganic salt, aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum and the like are known. Furthermore, basic polyaluminum hydroxide compounds (hereinafter also referred to as “basic polyaluminum chloride” and “polyaluminum chloride”), which are inorganic aluminum-containing cationic polymers, are known and preferably used.

The basic polyaluminum hydroxide compound has a main component represented by the following general formula 1, 2 or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , and the like, which are water-soluble polyaluminum hydroxides that stably contain basic and high-molecular polynuclear condensed ions.

[Al ₂ (OH) _n Cl _6-n ] _m ·· Formula 1
[Al (OH) ₃ ] _n AlCl ₃ .. Formula 2
Al _n (OH) _m Cl _(3n−m) 0 <m <3n Formula 3

  These are water treatment agents from Taki Chemical Co., Ltd. under the name of polyaluminum chloride (PAC), from Asada Chemical Co., Ltd. under the name of polyaluminum hydroxide (Paho), and from Riken Green Co., Ltd. It is the name of HAP-25, the name of Alphain 83 from Daimei Chemical Co., Ltd., and it is marketed from other manufacturers for the same purpose, and various grades can be easily obtained.

  In the present invention, the content of the water-soluble aluminum compound contained in the ink receiving layer can be, for example, 0.1 to 10% by mass with respect to the inorganic fine particles from the viewpoint of image quality to be formed. It is preferable that it is 5-8 mass%.

(Water-soluble resin)
The ink receiving layer in the invention preferably contains at least one water-soluble resin.
Examples of the water-soluble resin include polyvinyl alcohol resins that are resins having a hydroxy group as a hydrophilic structural unit [polyvinyl alcohol (PVA), acetoacetyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified. Polyvinyl alcohol, polyvinyl acetal, etc.], cellulose resins [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, etc.] , Chitins, chitosans, starch, resins with ether linkages [polyethylene oxide (PEO), Propylene oxide (PPO), poly ether (PVE)], and resins having carbamoyl groups [polyacrylamide (PAAM), polyvinyl pyrrolidone (PVP), polyacrylic acid hydrazide, etc.] and the like.
Moreover, the polyacrylic acid salt which has a carboxyl group as a dissociable group, maleic acid resin, alginate, gelatins, etc. can be mentioned.

Among these, the water-soluble resin used in the present invention is at least one selected from polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, and gelatins. In particular, polyvinyl alcohol (PVA) resin is preferable.
Examples of the polyvinyl alcohol include Japanese Patent Publication No. 4-52786, Japanese Patent Publication No. 5-67432, Japanese Patent Publication No. 7-29479, Japanese Patent No. 2537827, Japanese Patent Publication No. 7-57553, Japanese Patent No. 2502998, and Japanese Patent No. 3053231. JP-A-63-176173, JP-A-2604367, JP-A-7-276787, JP-A-9-207425, JP-A-11-58941, JP-A-2000-135858, JP-A-2001-205924, JP 2001-287444, JP 62-278080, JP 9-39373, JP 2750433, JP 2000-158801, JP 2001-213045, JP 2001-328345, JP 8 -324105, JP-A-11-348417, JP-A58-18168 JP, 10-259213, JP 2001-72711, JP 2002-103805, JP 2000-63427, JP 2002-308928, JP 2001-205919, JP 2002-264489. And the like described in each publication.
Examples of water-soluble resins other than polyvinyl alcohol resins include compounds described in JP-A-11-165461, [0011] to [0012], JP-A-2001-205919, and JP-A-2002-264489. The compounds described in the publication are also included.

  These water-soluble resins may be used alone or in combination of two or more. In the present invention, the content of the water-soluble resin is preferably 9 to 40% by mass, and more preferably 12 to 33% by mass with respect to the total solid content of the ink receiving layer.

The water-soluble resin and the inorganic fine particles, which mainly constitute the ink receiving layer in the invention, may each be a single material or a mixed system of a plurality of materials.
From the viewpoint of maintaining transparency, the type of water-soluble resin combined with inorganic fine particles, particularly silica fine particles, is important. When the gas phase method silica is used, the water-soluble resin is preferably a polyvinyl alcohol resin, more preferably a polyvinyl alcohol resin having a saponification degree of 70 to 100%, and a saponification degree of 80 to 99.5. % Of polyvinyl alcohol resin is particularly preferable.

The polyvinyl alcohol-based resin has a hydroxyl group in its structural unit. Since this hydroxyl group and the surface silanol group of the silica fine particle form a hydrogen bond, a three-dimensional network having a secondary particle of the silica fine particle as a network chain unit. It becomes easy to form a structure. By forming this three-dimensional network structure, it is considered that a porous ink receiving layer having a high porosity and sufficient strength is formed.
In ink jet recording, the porous ink receiving layer obtained as described above can absorb ink rapidly by a capillary phenomenon, and can form dots with good roundness without ink bleeding.

  In addition, the polyvinyl alcohol resin may be used in combination with the other water-soluble resin. When the other water-soluble resin and the polyvinyl alcohol resin are used in combination, the content of the polyvinyl alcohol resin in the total water-soluble resin is preferably 50% by mass or more, and more preferably 70% by mass or more.

-Content ratio of inorganic fine particles and water-soluble resin-
It is possible to further improve the film structure and film strength of the ink receiving layer by optimizing the mass content ratio [PB ratio (x: y)] of the inorganic fine particles (x) and the water-soluble resin (y). It is.

As the mass content ratio [PB ratio (x: y)] in the ink receiving layer, it is possible to prevent a decrease in film strength and cracking during drying caused by the PB ratio being too large, and the PB ratio is When it is too small, the gap is easily blocked by the resin, and the ratio of 1.5: 1 to 10: 1 is preferable from the viewpoint of preventing the ink absorbency from being lowered due to the decrease in the void ratio.
In particular, when the ink receiving layer is composed of two layers, the x / y ratio of the upper half of the ink receiving layer is equal to or greater than the x / y ratio of the lower half (the PB ratio is equal or lower in the upper half and the lower half). The side half is preferably binder-rich), and the upper half and the lower half preferably have the same PB ratio.

  Since stress may be applied to the recording medium when passing through the transport system of the ink jet printer, the ink receiving layer needs to have sufficient film strength. Further, when cutting into a sheet shape, the ink receiving layer needs to have sufficient film strength in order to prevent cracking or peeling of the ink receiving layer. In consideration of these cases, the mass ratio (x: y) is more preferably 5: 1 or less, while it is more preferably 2: 1 or more from the viewpoint of ensuring high-speed ink absorbency in an inkjet printer. preferable.

For example, a coating solution in which gas phase method silica fine particles having an average primary particle diameter of 20 nm or less and a water-soluble resin are completely dispersed in an aqueous solution at a mass ratio (x: y) of 2: 1 to 5: 1 is provided on the support. When the coating layer is dried, a three-dimensional network structure in which secondary particles of silica fine particles are network chains is formed, the average pore diameter is 30 nm or less, the porosity is 50 to 80%, the pore ratio A translucent porous film having a volume of 0.5 ml / g or more and a specific surface area of 100 m ² / g or more can be easily formed.

(Sulfur compounds)
The ink receiving layer in the invention preferably contains at least one sulfur compound from the viewpoint of further improving the ozone resistance.
The sulfur compound is at least one selected from thioether compounds, thiourea compounds, disulfide compounds, sulfinic acid compounds, thiocyanic acid compounds, sulfur-containing heterocyclic compounds, and sulfoxide compounds. Preferably, at least one of a thioether compound and a sulfoxide compound is more preferable, and at least one of a sulfoxide compound is more preferable.
Specific examples of the sulfur compound include compounds described in paragraph numbers 0053 to 0118 of JP-A No. 2008-246988.

(Magnesium salt)
The ink receiving layer in the invention preferably contains at least one magnesium salt from the viewpoint of further improving the ozone resistance.
Examples of the magnesium salt include magnesium acetate, magnesium oxalate, magnesium sulfate, magnesium chloride hexahydrate, and magnesium citrate nonahydrate.
Of these, magnesium chloride hexahydrate is preferred.

  Examples of commercially available magnesium salts include “White Nigari NS” and “Mag Chloride (Special Name) NS” manufactured by Naikai Shigyo Co., Ltd.

  Further, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the magnesium salt in the ink receiving layer is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass. Preferably, 0.2-2 mass% is especially preferable.

(Crosslinking agent)
The ink receiving layer in the invention preferably contains at least one crosslinking agent from the viewpoint of crosslinking the water-soluble resin.
The ink receiving layer in the present invention is preferably a porous layer in which the inorganic fine particles and the water-soluble resin are used in combination, and further cured by a crosslinking reaction between the crosslinking agent and the water-soluble resin.

Boron compounds are preferred for the crosslinking of the water-soluble resin, particularly polyvinyl alcohol. Examples of the boron compound include borax, boric acid, borate (eg, _{orthoborate, InBO 3, ScBO 3, YBO} 3, LaBO 3, Mg 3 (BO 3) 2, Co 3 (BO 3) 2, two borate _{(e.g., Mg 2 B 2 O 5,} Co 2 B 2 O 5), metaborate salts _{(e.g., LiBO 2, Ca (BO 2} ) 2, NaBO 2, KBO 2), tetraborate (eg, Na _{2 B 4 O 7 · 10H 2} O), can be mentioned five borate _{(e.g., KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O 5) or the like. Among them, Of these, borax, boric acid and borates are preferable, and boric acid is particularly preferable because a crosslinking reaction can be promptly caused.

The following compounds other than the boron compound can also be used as a crosslinking agent for the water-soluble resin.
For example, aldehyde compounds such as formaldehyde, glyoxal, and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5- Active halogen compounds such as triazine and 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide) ), Active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin; melamine resins (for example, methylolmelamine, alkylated methylolmelamine) ;Epoxy resin;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate; aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983611; carboximide compounds described in US Pat. No. 3,100,704; glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane-based compounds such as dioxane; titanium-containing aluminum sulfate, chromium alum, potassium alum, metal-containing compounds such as zirconyl acetate, chromium acetate, polyamine compounds such as tetraethylenepentamine, hydrazide compounds such as adipic acid dihydrazide, A low molecule or polymer containing two or more oxazoline groups can be used.
Said crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type.
1-50 mass% is preferable with respect to water-soluble resin, and, as for the usage-amount of a crosslinking agent, 5-40 mass% is more preferable.

(Water-soluble polyvalent metal salt)
The ink receiving layer in the invention preferably contains at least one water-soluble polyvalent metal compound in addition to the magnesium salt. For example, the water-soluble polyvalent metal compound functions as a mordant to further improve the ozone property.

The water-soluble polyvalent metal compound used in the present invention is preferably a trivalent or higher valent metal compound. For example, a water-soluble salt of a metal selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, tungsten, and molybdenum can be given.
Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, calcium butyrate, barium acetate, barium sulfate, barium phosphate, barium oxalate, barium naphthoresorcin carboxylate, barium butyrate, manganese chloride, manganese acetate, Manganese formate dihydrate, manganese ammonium sulfate hexahydrate, cupric chloride, ammonium copper (II) chloride dihydrate, copper sulfate, copper (II) butyrate, copper oxalate, copper phthalate, copper citrate , Copper gluconate, copper naphthenate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, cobalt acetate (II), cobalt naphthenate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, sulfuric acid Nickel ammonium hexahydrate, nickel amidosulfate tetrahydrate, sulfamic acid nitric acid , Nickel 2-ethylhexanoate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, aluminum acetate, aluminum lactate, basic aluminum thioglycolate, Ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, iron (III) citrate, iron (III) lactate trihydrate, iron triammonium trioxalate ( III) Trihydrate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zinc acetate, zinc lactate, zirconium acetate, zirconyl acetate, zirconium tetrachloride, zirconyl chloride, zirconium oxide octahydrate , Hydroxy zirconyl chloride, chromium acetate, chromium sulfate, sodium phosphotungstate, sodium citrate Stainless steel, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, etc., aluminum alum, basic polyaluminum hydroxide, zinc phenolsulfonate, zinc acetate And ammonium and zinc ammonium carbonate. Two or more of these water-soluble polyvalent metal compounds may be used in combination. In the present invention, the water solubility in the water-soluble polyvalent metal compound means that it is dissolved in water at 20 ° C. by 1% by weight or more.

  Among the above water-soluble polyvalent metal compounds, an aluminum compound or a compound composed of a Group 4A metal (for example, zirconium or titanium) in the periodic table is preferable, and an aluminum compound is more preferable. Particularly preferred is a water-soluble aluminum compound. The details of the water-soluble aluminum compound are as described above.

  As the water-soluble compound containing the Group 4A element of the periodic table, a water-soluble compound containing titanium or zirconium is more preferable. Examples of the water-soluble compound containing titanium include titanium chloride, titanium sulfate, titanium tetrachloride, tetraisopropyl titanate, titanium acetylacetonate, and titanium lactate. Zirconyl acetate, zirconyl chloride, zirconyl hydroxy chloride, zirconyl nitrate, basic zirconium carbonate, zirconium hydroxide, zirconyl lactate, zirconyl carbonate / ammonium carbonate, zirconyl carbonate / potassium carbonate, zirconyl sulfate, zirconyl fluoride Etc.

  The above-mentioned water-soluble polyvalent metal compound is preferably added at a ratio of 0.1 to 10% by mass, more preferably 0.5 to 8% by mass with respect to the inorganic fine particles.

(Other ingredients)
The ink receiving layer in the invention may contain other components such as a mordant other than the nitrogen-containing organic cationic polymer, magnesium salt, and water-soluble polyvalent metal salt, and various surfactants.
As other components, the components described in paragraph numbers 0088 to 0117 in JP-A-2005-14593, the components described in paragraph numbers 0138 to 0155 in JP-A-2006-321176, and the like are included. Can be appropriately selected and used.

The solid coating amount of the ink receiving layer in the present invention is not particularly limited, from the viewpoint of quality and productivity, for example, be a 20 g / m ² or less, it is 15 g / m ² or less preferably, and more preferably 3 to 15 g / ^{m 2.} In the present invention, the solid coating amount of the ink receiving layer means the sum of the solid coating amounts of all the ink receiving layers when the ink receiving layer is composed of two or more layers.

  When the ink receiving layer in the present invention is composed of two or more layers, a layer formed by a first coating solution containing inorganic fine particles and a nitrogen-containing organic cationic polymer, and a first layer containing inorganic fine particles and a water-soluble aluminum compound. It is preferable that the layer formed by the coating liquid 2 is laminated in order from the support side.

  The first coating liquid contains at least one inorganic fine particle and at least one nitrogen-containing organic cationic polymer, and if necessary, a water-soluble resin, a sulfur-based compound, a crosslinking agent, a water-soluble polyvalent metal salt, Other components can be further included. The second coating liquid contains at least one inorganic fine particle and at least one water-soluble aluminum compound, and if necessary, a water-soluble resin, a sulfur compound, a crosslinking agent, a water-soluble polyvalent metal salt, Other components can be further included.

The ink receiving layer in the present invention is preferably 2 or more layers are formed by stacking, the layer furthest from the support (hereinafter, "second layer" may be referred to) layer closer to the support than the ( Hereinafter, it is laminated so that the content of the nitrogen-containing organic cationic polymer in “the first layer” is large, and the content of the water-soluble aluminum compound in the first layer is higher than that in the second layer. It is preferable that the layers are laminated so that there are few.
By laminating so that the content of the nitrogen-containing organic cationic polymer in the first layer is higher than that in the second layer, the density of the recorded image is further improved and the ozone resistance is further improved.
Moreover, by laminating so that the content of the water-soluble aluminum compound in the first layer is less than that in the second layer, the occurrence of cracks is suppressed, the surface shape becomes better, and ozone resistance is further improved. More improved.

In the present invention, the distribution of the nitrogen-containing organic cationic polymer in the ink receiving layer can be confirmed by elemental analysis. Specifically, mapping analysis by the SEM-EDX method may be performed and the obtained image may be observed. In this case, the presence position of the entire ink receiving layer is confirmed by mapping analysis of the main component (for example, Si element) of the ink receiving layer, and then the mapping analysis of N element is performed to support the layer far from the support of the ink receiving layer. The mapping image determines which of the N elements in the layer close to the body is larger.
The presence distribution of the water-soluble aluminum compound in the ink receiving layer can be confirmed in the same manner.

In the present invention, the content ratio of the nitrogen-containing organic cationic polymer in the ink receiving layer (content in the layer far from the support of the ink receiving layer / content in the layer near the support of the ink receiving layer) is 1. It is preferably less than 0.
From the viewpoint of more effectively obtaining the effects of the present invention, the content ratio is more preferably 0 to 0.8, and still more preferably 0 to 0.4.
The ink receiving layer containing the nitrogen-containing organic cation polymer in the above content ratio is, for example, a content ratio of nitrogen-containing organic cation polymer (in the second coating solution) in the method for producing an inkjet recording medium of the present invention described later. (Content / content in the first coating solution) can be formed as described below.

Further, from the viewpoint of obtaining the effects of the present invention more effectively, the content of the nitrogen-containing organic cationic polymer in the first layer in the ink receiving layer is 2 with respect to the total solid content of the first layer. -25% by mass is preferable, 4-20% by mass is more preferable, and 6-18% by mass is particularly preferable.
On the other hand, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the nitrogen-containing organic cationic polymer in the second layer of the ink-receiving layer is 1 to 2 based on the total solid content of the second layer. 20 mass% is preferable, 2-15 mass% is more preferable, and 4-12 mass% is especially preferable.
Furthermore, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the nitrogen-containing organic cationic polymer in the entire ink receiving layer including the first layer and the second layer is as follows. 1-15 mass% is preferable with respect to the total solid of the whole, 1.5-12 mass% is more preferable, and 2-10 mass% is especially preferable.
In the present invention, the total solid content of the ink receiving layer refers to all components excluding water from the composition constituting the ink receiving layer.
Further, from the viewpoint of obtaining the effect of the present invention more effectively, the ratio of nitrogen-containing organic cation polymer / inorganic fine particles in the first layer is higher than the ratio of nitrogen-containing organic cation polymer / inorganic fine particles in the second layer. Larger is preferred.

In the present invention, the content ratio of the water-soluble aluminum compound in the ink receiving layer (content in the layer close to the support of the ink receiving layer / content in the layer far from the support of the ink receiving layer) is 1.0. It is preferable that it is less than.
From the viewpoint of more effectively obtaining the effects of the present invention, the content ratio is more preferably 0 to 0.8, and still more preferably 0 to 0.4.
The ink receiving layer containing the water-soluble aluminum compound in the above content ratio is, for example, a content ratio of the water-soluble aluminum compound [content in the first coating liquid] in the method for producing an inkjet recording medium of the present invention described later. / Content in the second coating solution] can be formed as described below.

Further, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the water-soluble aluminum compound in the second layer in the ink receiving layer is 2 to 2 with respect to the total solid content of the second layer. 25 mass% is preferable, 4-20 mass% is more preferable, and 6-18 mass% is especially preferable.
On the other hand, from the viewpoint of more effectively obtaining the effects of the present invention, the content of the water-soluble aluminum compound in the second layer of the ink receiving layer is 1 to 20 relative to the total solid content of the second layer. % By mass is preferable, 2 to 15% by mass is more preferable, and 4 to 12% by mass is particularly preferable.
Furthermore, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the water-soluble aluminum compound in the entire ink receiving layer including the first layer and the second layer is as follows. 1 to 15% by mass is preferable, 1.5 to 12% by mass is more preferable, and 2 to 10% by mass is particularly preferable.

  Further, from the viewpoint of improving the glossiness of the ink receiving layer, the ink receiving layer in the present invention is preferably composed of two or more layers, and the uppermost layer farthest from the support contains colloidal silica. Hereinafter, the uppermost layer containing colloidal silica is also referred to as a “colloidal silica layer”.

The layer thickness of the ink receiving layer is preferably an absorption capacity that can absorb liquid droplets to some extent (about touch-to-touch), and therefore the layer thickness of the ink receiving layer needs to be 5 μm or more, and 5 to 40 μm. It is preferable that it is 5-20 micrometers.
Moreover, 2-20 micrometers is preferable respectively and the layer thickness of the 1st layer in this invention and a 2nd layer has more preferable 5-20 micrometers.
On the other hand, the thickness of the colloidal silica layer that may be contained in the ink receiving layer is preferably 0.05 to 5 μm, more preferably 0.1 to 3 μm, from the viewpoint of ink absorbability and gloss.

The pore diameter of the ink receiving layer is preferably 0.005 to 0.030 μm, more preferably 0.01 to 0.025 μm in terms of median diameter.
The porosity and pore median diameter can be measured using a mercury porosimeter (trade name “Pore Sizer 9320-PC2” manufactured by Shimadzu Corporation).

Further, the ink receiving layer is preferably excellent in transparency, but as a guide, the haze value when the ink receiving layer is formed on a transparent film support is preferably 30% or less, More preferably, it is 20% or less.
The haze value can be measured using a haze meter (HGM-2DP: Suga Test Instruments Co., Ltd.).

  The ink jet recording medium of the present invention may further have an ink solvent absorbing layer, an intermediate layer, a protective layer and the like in addition to the ink receiving layer. Further, an undercoat layer may be provided on the support for the purpose of improving the adhesion between the ink receiving layer and the support and appropriately adjusting the electric resistance value.

  A polymer fine particle dispersion may be added to a constituent layer (for example, an ink receiving layer or a back coat layer) of the ink jet recording medium of the present invention. This polymer fine particle dispersion is used for the purpose of improving film properties such as dimensional stabilization, curling prevention, adhesion prevention, and film cracking prevention. The polymer fine particle dispersion is described in JP-A-62-245258 and JP-A-10-228076. If a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to the layer containing the mordant, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the back layer, curling can be prevented.

  The ink receiving layer may be provided only on one side of the support, or may be provided on both sides of the support for the purpose of preventing deformation such as curling.

<Inkjet recording medium manufacturing method>
Method of manufacturing an ink jet recording medium of the present invention, on at least one surface of the base paper, have the effect of weakening the interfiber bonding force, JAPAN TAPPI NO after 1 g / ^{m 2} coating or size press on the base paper. A coating liquid containing a surface sizing agent in which the wax pick value measured at 1: 2000 is 1 A or more lower than that before the coating or size pressing and resin particles having ink solvent absorbability is applied or size pressed. The total application amount of the surface sizing agent and the resin particles is 0.1 to 5.0 g / m ² , and the mass ratio of the surface sizing agent to the total application amount is 0.01 to 0.5. A step of providing an undercoat layer, a step of obtaining a support by subjecting the base paper substrate provided with the undercoat layer to a smoothing process using a calendar, and inorganic fine particles having an average primary particle size of 30 nm or less on the support. Providing an ink receiving layer.
By producing an ink jet recording medium by providing an ink receiving layer on a support obtained by such a production method, the occurrence of cockling and bronzing is suppressed, the image clarity and ink absorbability are excellent, and powder falling off during cutting is performed. An ink jet recording medium in which the occurrence of the above is suppressed can be efficiently produced.

The step of providing an undercoat layer in the present invention and the step of obtaining a support by smoothing are as described above.
For the step of providing the ink receiving layer on the obtained support, a commonly used method can be applied without particular limitation.
In the present invention, the step of providing the ink receiving layer includes vapor phase silica having an average primary particle diameter of 10 nm or less, polyvinyl alcohol, a crosslinking agent, an organic mordant, and a water-soluble polyvalent metal from the viewpoint of productivity and ink absorbability. It is preferable to include a step of coating the coating solution containing salt so that the solid content coating amount is 15 g / m ² or less.

  Specifically, the ink receiving layer is formed, for example, by applying a coating liquid for forming the ink receiving layer on the support to form a coating layer, and drying the coating layer to form the ink receiving layer. Can do. In addition, a coating liquid for forming the ink receiving layer is coated on the support to form a coating layer. (1) When the coating liquid is applied to the coating layer, (2) the coating liquid is added. At any time during the drying of the coating layer formed by coating and before the coating layer exhibits reduced-rate drying, a liquid containing a basic compound is applied and the coating layer is crosslinked and cured. It can manufacture with the manufacturing method containing a process.

When the ink receiving layer is formed from two or more types of coating solutions, each coating solution may be formed by simultaneous multilayer coating by a known method, or each coating solution may be formed by sequentially coating by a known method. May be. The simultaneous multilayer coating can be performed using a known coating apparatus such as an extrusion die coater or a curtain flow coater. The sequential coating can be performed using a known coating apparatus such as an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or a bar coater.
When the ink receiving layer is formed from one type of coating liquid, the ink receiving layer can be formed in the same manner as the sequential application.

  Regarding the details of the method for forming an ink receiving layer in the present invention, for example, the method for forming an ink receiving layer described in JP-A-2008-246988 can be suitably applied to the present invention.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

(Preparation of support 1)
Wood pulp consisting of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, 0.5 part of cationic polyacrylamide All the parts were added at an absolutely dry mass ratio to the pulp, and weighed with a long net paper machine to make a base paper of 170 g / m ² .
On the surface of the base paper obtained above (on the side where the image forming layer is provided), the coating solution for the undercoat layer having the composition shown below is applied with a bar coater so that the coating amount after drying is 8.0 g / m ^2. And dried to form an undercoat layer. Next, calendering was performed with a steel belt calender (Metso, steel belt temperature: 150 ° C., nip linear pressure: 20 kN / m, nip width: 1000 mm) to obtain a support having a density of 1.0 g / cm ³ . .

<Composition of coating solution 1 for undercoat layer>
・ Acrylic water dispersible latex ・ ・ ・ ・ ・ ・ ・ 3.0 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Alkyl ketene dimer ・ 1.0 part (surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide 4.0 parts (Inorganic pigment, TPEAKE R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 2)
In the production of the support 1, a support 2 was produced in the same manner as the production of the support 1 except that an undercoat layer coating solution having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of undercoat layer coating solution 2>
・ Acrylic water dispersible latex ・ ・ ・ ・ ・ ・ ・ 4.0 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Epoxidized fatty acid amide 1.0 part

(Preparation of support 3)
In the production of the support 1, a calender treatment is performed using a soft nip calender (soft nip, manufactured by Yodokou, rigid roll temperature: 150 ° C., nip linear pressure: 200 kN / m, nip width: 80 mm) instead of the steel belt calender. Except having performed, it carried out similarly to preparation of the support body 1, and obtained the support body 3 of density 1.0g / cm < ³ >.

(Preparation of support 4)
In the production of the support 1, a support 4 was produced in the same manner as the production of the support 1 except that the undercoat layer coating solution 4 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating solution 4 for undercoat layer>
・ Acrylic water dispersible latex ・ ・ ・ ・ ・ ・ ・ 4.0 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 5)
In the production of the support 1, the support 5 was produced in the same manner as the production of the support 1, except that the undercoat layer coating solution 5 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating solution 5 for undercoat layer>
・ Alkyl ketene dimer 1.0 parts (surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)

(Preparation of support 6)
Wood pulp composed of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, 0.5 part of cationic polyacrylamide All parts were added at an absolutely dry mass ratio to the pulp, and weighed with a long net paper machine to make a base paper of 170 g / m ^2. A steel belt calender (Metso, steel belt temperature: 150 ° C., nip linear pressure) : 20 kN / m, nip width: 1000 mm).
On the surface of the obtained base paper (side on which the image forming layer is provided), an undercoat layer coating solution 6 having the composition shown below is applied by a bar coater so that the coating amount after drying is 8.0 g / m ^2. Then, an undercoat layer was formed to obtain a support 6.
<Composition of coating liquid 6 for undercoat layer>
・ Acrylic water dispersible latex ・ ・ ・ ・ ・ ・ ・ 3.0 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Alkyl ketene dimer 1.0 parts (surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 7)
In the production of the support 1, the support 7 was produced in the same manner as the production of the support 1, except that the undercoat layer coating solution 7 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating solution 7 for undercoat layer>
・ Acrylic water-dispersible latex ・ ・ ・ ・ ・ ・ 0.07 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Alkyl ketene dimer 0.01 parts (Surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide: 0.4 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ 0.01 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 8)
In the production of the support 1, the support 8 was produced in the same manner as the production of the support 1, except that the undercoat layer coating solution 8 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating solution 8 for undercoat layer>
・ Acrylic water-dispersible latex ・ ・ ・ ・ ・ ・ ・ 1.6 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Alkyl ketene dimer 2.4 parts (Surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 9)
In the production of the support 1, the support 9 was produced in the same manner as the production of the support 1, except that the undercoat coating solution 9 having the following composition was used instead of the undercoat coating solution 1.
<Composition of coating liquid 9 for undercoat layer>
・ Acrylic water dispersible latex ・ ・ ・ ・ ・ ・ ・ 3.0 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Starch: 1.0 part (surface sizing agent, starch)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 10)
In the production of the support 1, a support 10 was produced in the same manner as the production of the support 1 except that the undercoat layer coating solution 10 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating solution 10 for undercoat layer>
・ Styrene-butadiene latex ・ ・ ・ ・ ・ ・ ・ 3.0 parts
(Resin particles, SR-103, manufactured by Nippon A & L)
・ Alkyl ketene dimer 1.0 parts (surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 11)
In the production of the support 1, a support 10 was produced in the same manner as the production of the support 1 except that the undercoat layer coating solution 11 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating solution 11 for undercoat layer>
・ Styrene-butadiene latex ・ ・ ・ ・ ・ ・ ・ 1.9 parts
(Resin particles, SR-103, manufactured by Nippon A & L)
・ Alkyl ketene dimer 0.02 part (surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide ・ ・ ・ 3.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ 0.05 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 12)
In the production of the support 1, the support 12 was produced in the same manner as the production of the support 1, except that the undercoat coating solution 12 having the following composition was used instead of the undercoat coating solution 1.
<Composition of coating liquid 12 for undercoat layer>
・ Acrylic water-dispersible latex ・ ・ ・ ・ ・ ・ ・ 2.2 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Alkyl ketene dimer 0.02 part (surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide ・ ・ ・ 3.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ 0.05 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 13)
In the preparation of the support 1, except for using the coating solution for undercoat layer 13 having the following composition in place of the coating solution for undercoat layer 1 in the same manner as in the preparation of the support 1, to prepare a support 13.
<Composition of coating solution 13 for undercoat layer>
・ Acrylic water-dispersible latex ・ ・ ・ ・ ・ ・ 1.05 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Alkyl ketene dimer ・ ・ ・ 1.01 parts (Surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide ・ ・ ・ 3.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ 0.05 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 14)
In the production of the support 1, the support 14 was produced in the same manner as the production of the support 1, except that the undercoat layer coating solution 14 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating solution 14 for undercoat layer>
・ Acrylic water dispersible latex ・ ・ ・ ・ ・ ・ ・ 3.0 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Polyhydric alcohol fatty acid ester compound ・ 1.0 parts (Surface sizing agent, KB-110, manufactured by Kao Corporation)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 15)
In the production of the support 1, the support 15 was produced in the same manner as the production of the support 1, except that the undercoat coating solution 15 having the following composition was used instead of the undercoat coating solution 1.
<Composition of coating solution 15 for undercoat layer>
・ Vinylidene chloride latex ・ ・ ・ ・ ・ ・ ・ 3.0 parts
(Resin particles, Saran latex L411A, manufactured by Asahi Kasei Chemicals)
・ Alkyl ketene dimer 1.0 parts (surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 16)
In the production of the support 1, the support 16 was produced in the same manner as the production of the support 1, except that the undercoat layer coating solution 16 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating liquid 16 for undercoat layer>
・ Acrylic water dispersible latex ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 6.0 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Alkyl ketene dimer 2.0 parts (surface sizing agent, SKS296, manufactured by Arakawa Chemical Industries)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Creation of support 17)
In the production of the support 1, the support 17 was produced in the same manner as the production of the support 1, except that the undercoat coating solution 17 having the following composition was used instead of the undercoat coating solution 1.
<Composition of coating solution 17 for undercoat layer>
・ Acrylic water-dispersible latex ・ ・ ・ ・ ・ ・ 0.7 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Alkyl ketene dimer 0.3 parts (Surface sizing agent, SKS296, Arakawa Chemical Industries)
・ Titanium oxide: 2.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ 0.05 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 18)
In the production of the support 1, the support 18 was produced in the same manner as the production of the support 1, except that the undercoat layer coating solution 18 having the following composition was used instead of the undercoat layer coating solution 1.
<Composition of coating liquid 18 for undercoat layer>
・ Acrylic water dispersible latex ・ ・ ・ ・ ・ ・ ・ 3.0 parts
(Resin particles, Aquabrid AQ4635, manufactured by Daicel Chemical Industries)
・ Fatty acid diamide 1.0 part (Surface sizing agent, ethylenebisstearic acid amide, Alflow H-50ES, manufactured by Japan PMC)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

(Preparation of support 19)
In the production of the support 1, a support 19 was produced in the same manner as the production of the support 1, except that the undercoat coating solution 19 having the following composition was used instead of the undercoat coating solution 1.
<Composition of coating liquid 19 for undercoat layer>
・ Acrylic urethane latex ・ 3.0 parts
(Resin particles, WEM-202U, manufactured by Taisei Fine Chemical)
・ Fatty acid amide 1.0 part (Surface sizing agent, PT-203, manufactured by Starlight PMC)
・ Titanium oxide: 4.0 parts (Inorganic pigment, Tyco R780-2, manufactured by Ishihara Sangyo)
・ Fluorescent whitening agent ・ ・ ・ ・ ・ ・ ・ 0.1 parts (Tinopal SFP, manufactured by Ciba Japan)

[Formation of Ink Receiving Layer R-1]
(Preparation of coating liquid A for forming an ink receiving layer)
In accordance with the composition of “silica dispersion A” below, silica fine particles, ion-exchanged water, dimethyldiallylammonium chloride polymer (Daiichi Kogyo Seiyaku Co., Ltd., Charol DC902P) and zirconyl acetate are mixed, and a liquid-liquid collision type disperser (Sugino Then, the dispersion was heated to 45 ° C. and held for 20 hours to prepare silica dispersion A.
To the obtained silica dispersion A, 31.2 parts of a polyvinyl alcohol (water-soluble resin) solution A having the following composition was added at 30 ° C. to prepare a coating liquid A for forming an ink receiving layer.
The mass ratio of the silica fine particles to the water-soluble resin in the ink-receiving layer forming coating liquid A (P / B ratio = silica fine particles / water-soluble resin) was 4/1, and the pH was 3.4.

"Silica dispersion A"
(1) Silica fine particles: 8.9 parts (Nippon Aerosil Co., Ltd., AEROSIL300SF75)
(2) Ion-exchanged water: 1.0 part (3) “Charol DC-902P” (51.5% solution): 0.78 part (Daiichi Kogyo Seiyaku Co., Ltd., dispersant)
(4) Zirconyl acetate (50% solution): 0.48 parts (Dilcozol ZA-30, manufactured by Daiichi Elemental Chemical Co., Ltd.)

"Polyvinyl alcohol (water-soluble resin) solution A"
(1) Polyvinyl alcohol: 2.2 parts (manufactured by Nippon Acetate / Poval, “JM-33”, saponification degree 94.3 mol%, polymerization degree 3300)
(2) Ion-exchanged water: 28.2 parts (3) Diethylene glycol monobutyl ether: 0.7 parts (Kyowa Hakko Chemical Co., Ltd., Butisenol 20P)
(4) Polyoxyethylene lauryl ether: 0.1 part (manufactured by Kao Corporation, Emulgen 109P)

(Preparation of coating liquid B for forming an ink receiving layer)
In accordance with the composition of “silica dispersion B” below, silica fine particles, ion exchange water, dimethyldiallylammonium chloride polymer (Daiichi Kogyo Seiyaku Co., Ltd., Charol DC902P), zirconyl acetate, methionine sulfoxide, and boric acid are mixed. After dispersing with a collision type disperser (manufactured by Sugino Machine Co., Ltd., an optimizer), the dispersion was heated to 45 ° C. and held for 20 hours to prepare silica dispersion B.
Next, 31.2 parts of a polyvinyl alcohol (water-soluble resin) solution B having the following composition in the silica dispersion B and a cation-modified polyurethane (Daiichi Kogyo Seiyaku Co., Ltd., Superflex 650 (25% solution)) 3. 1 part was added at 30 ° C. to prepare a coating liquid B for forming an ink receiving layer.
The mass ratio of the silica fine particles to the water-soluble resin in the ink-receiving layer-forming coating liquid B (P / B ratio = silica fine particles / water-soluble resin) was 4/1, and the pH was 3.8.

"Silica dispersion B"
(1) Silica fine particles: 8.9 parts (Nippon Aerosil Co., Ltd., AEROSIL300SF75)
(2) Ion-exchanged water: 1.0 part (3) “Charol DC-902P” (51.5% solution): 0.78 part (Daiichi Kogyo Seiyaku Co., Ltd., dispersant)
(4) Zirconyl acetate (50% solution): 0.24 parts (Dilcosol ZA-30, manufactured by Daiichi Elemental Chemical Co., Ltd.)
(5) 30% methionine sulfoxide: 1.76 parts (6) Boric acid (crosslinking agent): 0.4 parts

"Polyvinyl alcohol (water-soluble resin) solution B"
(1) Polyvinyl alcohol: 2.2 parts (manufactured by Nippon Acetate / Poval, “JM-33”, saponification degree 94.3 mol%, polymerization degree 3300)
(2) Ion-exchanged water: 28.2 parts (3) Diethylene glycol monobutyl ether: 0.7 parts (Kyowa Hakko Chemical Co., Ltd., Butisenol 20P)
(4) Polyoxyethylene lauryl ether: 0.1 part (manufactured by Kao Corporation, Emulgen 109P)

<Example 1>
[Preparation of Inkjet Recording Medium 1]
It was subjected to corona discharge treatment in the undercoat layer of the support obtained above, the ink receiving layer coating solution B with respect to 49 ml / m ^2, an in-line solution having the following composition in 3.2 ml / m ² Lower layer coating solution mixed in-line at a speed and 44 ml / m ² of coating solution A for forming an ink-receiving layer An in-line coating composed of the following composition is mixed in-line at a rate of 9.6 ml / m ² The liquid and the coating layer were simultaneously applied with an extrusion die coater to form a coating layer.
Then, it is dried at 90 ° C. (dew point 5 ° C.) (wind speed 3 to 8 m / sec) with a hot air dryer until the solid content concentration of the coating layer becomes 17%, and then the solid content concentration of the coating layer is 24%. It was made to dry at 55 degreeC (dew point 5 degreeC) until it became (wind speed 3-8 m / sec). The coating layer showed a constant rate of drying during this period.
Immediately after that, it was immersed in a solution containing a basic compound having the following composition for 3 seconds to deposit 6.5 g / m ² on the coating layer, and further dried at 72 ° C. for 10 minutes. As a result, the ink receiving layer R-1 having a dry film thickness of 17.5 μm was provided on the support, and the ink jet recording medium 1 was obtained.

"Inline liquid"
(1) Polyaluminum chloride aqueous solution: 2.0 parts (Daimei Chemical Co., Ltd., Alpha-in 83, Basicity 83%)
(2) Ion-exchanged water: 7.8 parts (3) SC-505 (manufactured by Haimo Co., Ltd.): 0.2 parts

“Solutions containing basic compounds”
(1) Boric acid: 1.3 parts (2) Ammonium carbonate (first grade): 5.0 parts (Kanto Chemical Co., Inc.)
(3) Ammonium zirconium carbonate (28% aqueous solution): 2.5 parts (Zircosol AC-7, manufactured by Daiichi Elemental Chemical Co., Ltd.)
(4) Ion-exchanged water: 85.2 parts (5) Polyoxyethylene lauryl ether: 6.0 parts (manufactured by Kao Corporation, Emulgen 109P, 10% aqueous solution, HLB value 13.6)

<Examples 2 to 10>
Ink jet recording media 2 to 10 were obtained in the same manner as in Example 1 except that the support shown in Table 1 below was used instead of the support 1 in the production of the ink jet recording medium of Example 1.

<Comparative Examples 1-3, 5-10>
Ink jet recording media were obtained in the same manner as in Example 1 except that the support shown in Table 1 was used instead of the support 1 in the production of the ink jet recording medium of Example 1.

<Comparative example 4>
[Formation of Ink Receiving Layer R-2]
(Preparation of inkjet recording medium)
Water was added to the following ink receiving layer composition, and an ink receiving layer coating solution having a solid concentration of 25% by weight was prepared by a conventional method.
The obtained ink receiving layer coating solution was applied to the support 1 so as to have a solid content of 12 g / m ² and dried to obtain an ink jet recording medium.
[Ink-receiving layer composition]
Synthetic amorphous silica: 100 parts (average primary particle size: 50 nm, average secondary particle size: 3.5 μm)
-Sodium hexametaphosphate: 1 part-Silanol-modified polyvinyl alcohol: 42.5 parts (Polymerization degree 1700, manufactured by Kuraray Co., Ltd .: R-1130)
・ Fluorescent whitening agent: 3 parts ・ Anionic surfactant: 7 parts ・ Polydimethyldiaminoammonium chloride: 1 part ・ Polyamide polyamine epichlorohydrin: 3.5 parts (Arakawa Chemical Industries, Arafix 300) It was.

In Table 1, the amount of DEGMBE liquid absorption is specified in JIS P8140 using a 15% aqueous solution of diethylene glycol monobutyl ether (DEMBB) after coating each resin particle on the surface of the base paper at a solid content of 2 g / m ² and drying. It is the measured value of the liquid absorption when the Cobb water absorption test (contact time 2 minutes) is performed.
Also, delta wax pick value, JAPAN TAPPI NO.1 from the wax pick value of base paper is measured according to the standards of (2000), 1g / ^{m 2} coated with a solid content coating amount of each surface sizing agent surface of the base paper After drying, it is a value obtained by subtracting the wax pick value measured in accordance with the regulations of JAPAN TAPPI NO.1 (2000).

<Evaluation>
The following evaluation was performed about the support body and inkjet recording medium which were obtained above. The evaluation results are shown in Table 2.

(Cockling)
Cockling when the ink receiving layer coating solution was applied to each support obtained above was visually observed and evaluated according to the following evaluation criteria.
~Evaluation criteria~
AA ... no cockling was seen.
BB ... Cock ring was slightly seen.
CC: A little cockling was observed, but there was no practical problem.
DD: Cock rings were observed over the entire surface, and there were practical problems.

(Image clarity)
A black (K) solid image was printed on each ink jet recording medium using an ink jet printer PM-G800 (manufactured by Seiko Epson Corporation) to prepare a measurement sample.
The obtained sample for measurement was measured for image clarity C value based on JIS H8866-2 using image clarity measuring machine (ICM-1 (manufactured by Suga Test Instruments Co., Ltd.)) and evaluated according to the following evaluation criteria. did.
The measurement conditions are as follows.
Measurement method: reflection, measurement angle: 60 degrees, optical comb; measured at 1.0 mm.
~Evaluation criteria~
AA: Image clarity C value of 50% or more.
BB: Image clarity C value of 30% or more and less than 50%.
CC: Image clarity C value of 20% or more and less than 30%.
DD: Less than 20%.

(Bronzing)
For each inkjet recording medium, an inkjet printer PX-G930 (manufactured by Seiko Epson Corporation) was used to eject cyan ink at the maximum ink ejection amount, and a solid image was printed to prepare an evaluation sample. The obtained sample for evaluation was visually observed, and bronzing was evaluated according to the following evaluation criteria.
~Evaluation criteria~
AA: The occurrence of bronzing was hardly confirmed.
BB: The occurrence of bronzing was slightly confirmed.
CC: The occurrence of bronzing was confirmed, but to the extent that there was no practical problem.
DD: The occurrence of bronzing was clearly confirmed, which hindered practical use.

(Powder falling)
Each ink-jet recording medium (A4 plate) was stacked 250 sheets each, and the test of cutting with a guillotine cutter from the surface opposite to the ink receiving layer forming surface was repeated 6 times, and the amount of generated paper dust was visually observed and evaluated as follows. Evaluation was made according to criteria.
~Evaluation criteria~
AA: Paper dust was hardly generated.
BB: Generation of paper dust was slightly recognized.
CC: Although generation | occurrence | production of paper dust was recognized a little, it was a grade which does not have a problem practically.
DD: There was much generation of paper dust, and there was a problem in practical use.

(image quality)
With respect to each inkjet recording medium, an image of a person and a landscape was printed and visually observed using an inkjet printer PM-G800 (manufactured by Seiko Epson Corporation), and the image quality was evaluated according to the following evaluation criteria.
~Evaluation criteria~
AA: The image quality was very good.
BB: The image quality was good.
CC: Although the image quality is slightly inferior, it was not a problem in practical use.
DD: Image quality was inferior.

  From Table 2, it can be seen that the ink jet recording medium of the present invention has excellent image clarity, suppresses the occurrence of bronzing, and suppresses the occurrence of powder falling during the cutting process. Furthermore, it can be seen that the support in the present invention can suppress the occurrence of cockling during the formation of the ink receiving layer.

Claims (12)

A support having an undercoat layer provided on at least one side of the base paper, and an ink receiving layer provided on the undercoat layer,
The support is coated with JAPAN TAPPI NO. 1 after applying or size pressing 1 g / m ^{2 on the} base paper. A surface sizing agent in which a wax pick value measured in accordance with 1: 2000 is 1 A or more lower than that before the application or size pressing, and a coating liquid containing resin particles having ink solvent absorptivity, The surface is applied to at least one side of the base paper by application or a size press, and the total application amount of the surface sizing agent and the resin particles is 0.1 g / m ^{2 to} 5.0 g / m ² , and the surface with respect to the total application amount After providing the undercoat layer so that the mass ratio of the sizing agent is 0.01 to 0.5, it is a support obtained by smoothing with a calendar,
The ink receiving layer is an ink jet recording medium containing inorganic fine particles having an average primary particle diameter of 30 nm or less.   The surface sizing agent includes alkyl ester resins, alkyl ether resins, alkylamides, alkyl ketene dimers, aminoammonium salts, fatty acid-containing compounds having 10 to 30 carbon atoms, fatty acid polyamide polyamine, fatty acid polyamide polyamine epichlorohydrin condensate, fatty acid At least one selected from the group consisting of diamidodiamine, fatty acid monoamide, fatty acid diamide, polyalkylene polyamine fatty acid epichlorohydrin condensate, epoxidized fatty acid amide, fatty acid diamide salt, alkylene oxide adduct of fatty acid ester, and fatty acid quaternary ammonium salt The inkjet recording medium according to claim 1, which is a seed.   The resin particles are at least selected from the group consisting of acrylic resins, acrylic silicon resins, acrylic epoxy resins, acrylic urethane resins, styrene-butadiene resins, acrylonitrile-butadiene resins, and vinyl acetate resins. The ink jet recording medium according to claim 1, wherein the ink jet recording medium is one type.   4. The inkjet recording medium according to claim 1, wherein the resin particles have a glass transition temperature (Tg) of −10 ° C. to 85 ° C. 5.   5. The ink jet recording medium according to claim 1, wherein the inorganic fine particles are at least one selected from the group consisting of vapor phase method silica, colloidal silica, and alumina hydrate. The ink receiving layer includes a layer containing vapor phase silica having an average primary particle size of 10 nm or less, polyvinyl alcohol, a crosslinking agent, an organic mordant, and a water-soluble polyvalent metal salt, and the total mass of the ink receiving layer is It is 15 g / m < ² > or less, The inkjet recording medium of any one of Claims 1-5. The undercoat layer further includes at least one of an inorganic pigment and a fluorescent brightening agent, and the density of the support is 0.7 to 1.15 g / cm ^3. The ink jet recording medium according to Item. A method for producing an ink jet recording medium having an undercoat layer and an ink receiving layer on at least one side of a base paper,
After coating or size pressing 1 g / m ^{2 on the} base paper, JAPAN TAPPI NO. A surface sizing agent in which a wax pick value measured in accordance with 1: 2000 is 1 A or more lower than that before the application or size pressing, and a coating liquid containing resin particles having ink solvent absorptivity, The surface is applied to at least one side of the base paper by application or a size press, and the total application amount of the surface sizing agent and the resin particles is 0.1 g / m ^{2 to} 5.0 g / m ² , and the surface with respect to the total application amount Providing an undercoat layer so that the mass ratio of the sizing agent is 0.01 to 0.5;
A step of smoothing the base paper provided with the undercoat layer with a calendar to obtain a support; and
Providing an ink receiving layer containing inorganic fine particles having an average primary particle size of 30 nm or less on the support;
A method for producing an inkjet recording medium comprising:   The inkjet according to claim 8, wherein the smoothing process using the calendar is performed by using a calendar having a nip width of 50 mm or more, a metal roll or a steel belt, and a surface temperature of the metal roll or the steel belt being 110 ° C. or more. A method for manufacturing a recording medium.   The method for producing an ink jet recording medium according to claim 8 or 9, wherein the smoothing process using the calendar is performed using a calendar including a steel belt. The step of providing the ink receiving layer is performed by applying a coating solution containing vapor phase silica having an average primary particle size of 10 nm or less, polyvinyl alcohol, a crosslinking agent, an organic mordant, and a water-soluble polyvalent metal salt, with a solid content coating amount of 15 g. The manufacturing method of the inkjet recording medium of any one of Claims 8-10 including the process apply | coated so that it may become / m < ² > or less.   The step of providing the undercoat layer includes a step of applying or size pressing a coating solution containing at least one of the resin particles, the surface sizing agent, and an inorganic pigment and a fluorescent brightening agent. 11. A method for producing an ink jet recording medium according to any one of 11 above.