Abstract: An ink jet recording medium including a substrate and two or more ink receiving layers provided on the substrate, wherein a first ink receiving layer that is an outermost ink receiving layer of the two or more ink receiving layers and a second ink receiving layer adjacent to the first ink receiving layer contain an alumina pigment, polyvinyl alcohol and boric acid. The first ink receiving layer contains polyvinyl alcohol in an amount of 7.0-10.5% by mass or less based on the alumina pigment and contains boric acid in an amount of 1.1-1.4% by mass or less based on the alumina pigment. The second ink receiving layer contains polyvinyl alcohol in an amount of 10.5-17.0% by mass or less based on the alumina pigment and contains boric acid in an amount of 1.5-2.5% by mass or less based on the alumina pigment.

Abstract: A recording medium includes an ink-receiving layer on a substrate, in which the ink-receiving layer contains a hydrated alumina, an alkylsulfonic acid having 1 to 4 carbon atoms, and at least one salt of a sulfur compound represented by general formula (1) or (2): R1—SO2M1??general formula (1) R2—SO2—SM2??general formula (2) wherein R1 and R2 each represent an alkyl group, an aryl group, or a heterocyclic group; and M1 and M2 each represent an alkali metal, ammonium, or an alkanolamine. The proportion of the alkylsulfonic acid having 1 to 4 carbon atoms is in the range of 1.0% by mass to 2.0% by mass with respect to the hydrated alumina. The proportion of the salt of the sulfur compound is in the range of 0.2% by mass to 4.0% by mass with respect to the hydrated alumina.

Abstract: The invention provides a recording medium having 2 or more ink receiving layers on a substrate, wherein an upper layer of the ink receiving layers, which is a layer most distant from the substrate, and a lower layer, which is a layer located just under the upper layer, contain at least one selected from alumina hydrate and alumina, an acid and a hydrophilic binder, the acid contained in the upper layer is a carboxylic acid represented by the general formula [I], and the acid contained in the lower layer is a sulfonic acid represented by the general formula [II] R1—COOH??General formula [I] R2—SO3H.

Abstract: An inkjet recording medium includes a support and an ink-receiving layer which is disposed on the support and which contains an alumina pigment and an alkylsulfonic acid having the carbon number of 1 or more and 4 or less. The ink-receiving layer further contains a polymeric compound, a water-soluble zirconium compound, and boric acid or a borate. The polymeric compound is one obtained by cationizing at least one amino group of a product with acid, the product being obtained by the reaction of at least three compounds, that is, (i) a sulfur-containing organic compound containing two or more active hydrogen atoms, (ii) a polyisocyanate compound containing two or more isocyanate groups, and (iii) an amine compound containing two or more active hydrogen atoms.

Abstract: The invention provides a recording medium comprising a substrate and an ink receiving layer that is provided on the substrate and contains alumina hydrate and a binder. A surface of the ink receiving layer is covered with a partial coating formed by a plurality of coatings containing a cationic polyurethane. The plurality of coatings have an average major diameter of 0.03 ?m or more and less than 1.00 ?m. The partial coating provides a coverage of 10% or more and less than 70% with respect to the surface of the ink receiving layer.

Abstract: A recording medium includes a support; and an ink-receiving layer, the ink-receiving layer having a lower layer and an upper layer, in which the lower layer contains fine inorganic particles, polyvinyl alcohol, and boric acid, the fine inorganic particles including at least one compound selected from alumina, hydrated alumina, and vapor-phase-process silica, in which the upper layer contains fine inorganic particles, polyvinyl alcohol, and boric acid, the fine inorganic particles including at least one compound selected from alumina and hydrated alumina, in which the lower layer has a boric acid content of 2.0% by mass to 7.0% by mass with respect to polyvinyl alcohol, and in which the upper layer has a boric acid content of 10.0% by mass to 30.0% by mass with respect to polyvinyl alcohol.

Abstract: An ink jet recording medium including a substrate and two or more ink receiving layers provided on the substrate, wherein a first ink receiving layer that is an outermost ink receiving layer of the two or more ink receiving layers and a second ink receiving layer adjacent to the first ink receiving layer contain an alumina pigment, polyvinyl alcohol and boric acid. The first ink receiving layer contains polyvinyl alcohol in an amount of 7.0-10.5% by mass or less based on the alumina pigment and contains boric acid in an amount of 1.1-1.4% by mass or less based on the alumina pigment. The second ink receiving layer contains polyvinyl alcohol in an amount of 10.5-17.0% by mass or less based on the alumina pigment and contains boric acid in an amount of 1.5-2.5% by mass or less based on the alumina pigment.

Abstract: An ink jet recording medium including a substrate and an ink receiving layer provided on the substrate and composed of two or more layers of at least an upper layer and a lower layer. The ink receiving layer contains polyvinyl alcohol in an amount of 12.7% by mass or more based on the total mass of the ink receiving layer. The upper layer is a layer most distant from the substrate, contains a pigment and polyvinyl alcohol, the pigment containing 90% by mass or more of alumina hydrate, and has a thickness of 3.0-10.0 ?m. The lower layer is positioned just under the upper layer, contains a pigment and polyvinyl alcohol, the pigment containing 20% by mass or more of silica, and has a thickness 2.5-10 times larger than that of the upper layer and an average pore radius 0.90-1.30 times larger than that of the upper layer.

Abstract: A recording medium includes an ink-receiving layer on a substrate, in which the ink-receiving layer contains a hydrated alumina, an alkylsulfonic acid having 1 to 4 carbon atoms, and at least one salt of a sulfur compound represented by general formula (1) or (2): R1—SO2M1??general formula (1) R2—SO2—SM2??general formula (2) wherein R1 and R2 each represent an alkyl group, an aryl group, or a heterocyclic group; and M1 and M2 each represent an alkali metal, ammonium, or an alkanolamine. The proportion of the alkylsulfonic acid having 1 to 4 carbon atoms is in the range of 1.0% by mass to 2.0% by mass with respect to the hydrated alumina. The proportion of the salt of the sulfur compound is in the range of 0.2% by mass to 4.0% by mass with respect to the hydrated alumina.

Abstract: A recording medium includes an ink-receiving layer on a substrate, in which the ink-receiving layer contains hydrated alumina, a C1-4 alkylsulfonic acid, and a salt of a compound of general formula (1): X1?R1?(S)n?R2?X2, wherein n represents 1 or 2; X1 and X2 each independently represent H, NH2, or COOH, and at least one of X1 and X2 represents NH2 or COOH; R1 and R2 each independently represent alkylene, arylene, or heteroarylene, and they may be bonded to each other to form a ring, upon letting the proportion of the C1-4 alkylsulfonic acid be A percent by mass with respect to hydrated alumina, A is in the range of 1.0 to 2.0, and upon letting the proportion of the salt of the compound of general formula (1) be B percent by mass with respect to hydrated alumina, B is in the range of 0.5 to 5.0.

Abstract: The invention provides a recording medium having excellent ink absorbency and capable of forming a sharp image thereon. The recording medium has a substrate, and a first layer and an outermost layer provided on the substrate in this order, wherein the first layer contains at least one of alumina and alumina hydrate, the outermost layer contains a pigment and is lower in refractive index than the first layer, and the absolute dry coating amount of the outermost layer is 0.1 g/m2 or more and 0.5 g/m2 or less.

Abstract: In an ink jet recording medium having at least two ink receiving layers, the total content of boric acid, a borate, and a water-soluble zirconium salt of a lower ink receiving layer located close to a support substrate to the total content of alumina and an alumina hydrate thereof is higher than the total content of boric acid, a borate, and a water-soluble zirconium salt of an upper ink receiving layer located apart from the support substrate to the total content of alumina and an alumina hydrate thereof.

Abstract: The invention provides a method for producing a recording medium, comprising a step of coating one or more ink receiving layers provided on at least one surface of a substrate with an outermost layer coating liquid to form an outermost layer, an ink receiving layer, of said one or more ink receiving layers, which is nearest to the outermost layer containing alumina hydrate and a binder. The outermost layer coating liquid contains monodispersive and spherical cationic colloidal silica particles having an average particle size of 30 nm or more and 60 nm or less, polyvinyl alcohol having a saponification degree of 75% by mol or more and 85% by mol or less and a viscosity-average polymerization degree of 1,500 or more and 2,200 or less, and cationic polyurethane emulsion particles having an average particle size of 10 nm or more and 100 nm or less.

Abstract: The invention provides a recording medium comprising a substrate and an ink receiving layer that is provided on the substrate and contains alumina hydrate and a binder. A surface of the ink receiving layer is covered with a partial coating formed by a plurality of coatings containing a cationic polyurethane. The plurality of coatings have an average major diameter of 0.03 ?m or more and less than 1.00 ?m. The partial coating provides a coverage of 10% or more and less than 70% with respect to the surface of the ink receiving layer.

Abstract: The invention provides a recording medium having 2 or more ink receiving layers on a substrate, wherein an upper layer of the ink receiving layers, which is a layer most distant from the substrate, and a lower layer, which is a layer located just under the upper layer, contain at least one selected from alumina hydrate and alumina, an acid and a hydrophilic binder, the acid contained in the upper layer is a carboxylic acid represented by the general formula [I], and the acid contained in the lower layer is a sulfonic acid represented by the general formula [II].