A recording medium substrate in an aspect of the present invention is a recording medium substrate having a base paper and a stretched film layer on the base paper, wherein the stretched film layer has a thickness of 70 μm or more, and the recording medium substrate has an average surface roughness of 0.3 μm or less. A recording medium in another aspect of the present invention includes a recording medium substrate, a first ink receiving layer on the recording medium substrate, and a second ink receiving layer on the first ink receiving layer, wherein the first ink receiving layer is in contact with the second ink receiving layer, the first ink receiving layer contains an alumina hydrate and a hydroxy acid, the second ink receiving layer contains an alumina hydrate and a sulfonic acid.

A thermal transfer ribbon comprising a dye layer and a transferable protective layer repeatedly formed on one surface of a substrate, the transferable protective layer having a first layer formed on the substrate, and a second layer formed on the first layer. The first layer comprises an acrylic resin (X) containing methyl methacrylate, an acrylic resin (Y) containing a styrene resin, and a polyester resin (Z). X has a weight average molecular weight of 120000 or more, the mass ratio of X and Y is within the range of 1:9 to 9:1, and the mass of Z is 1% or more and 3% or less of the total mass of X and Y.

A thermal transfer ribbon comprising a dye layer and a transferable protective layer repeatedly formed on one surface of a substrate, the transferable protective layer having a first layer formed on the substrate, and a second layer formed on the first layer. The first layer comprises an acrylic resin (X) containing methyl methacrylate, an acrylic resin (Y) containing a styrene resin, and a polyester resin (Z). X has a weight average molecular weight of 120000 or more, the mass ratio of X and Y is within the range of 1:9 to 9:1, and the mass of Z is 1% or more and 3% or less of the total mass of X and Y.

A method for manufacturing a thermal transfer image-receiving sheet support that can be used to obtain a thermal transfer image-receiving sheet that maintains its gloss and that has excellent handleability and high condition uniformity while preventing the formation of air bubbles in an adhesive layer. A resin is supplied to one side of a substrate, which is passed between a cooling roller A and a rubber roller A. A porous film is stacked on another side of the substrate through a resin, and the substrate is passed between a cooling roller B and a rubber roller B. The cooling rollers A and B have surfaces with a ten-point average roughness (Rz) of 5 to 30 m and 0 to 20 m, respectively. The rubber rollers A and B have a rubber hardness (durometer (Type A)) of 60 to 95 and 50 to 80, respectively.

A method for manufacturing a thermal transfer image-receiving sheet support that can be used to obtain a thermal transfer image-receiving sheet that maintains its gloss and that has excellent handleability and high condition uniformity while preventing the formation of air bubbles in an adhesive layer. A resin is supplied to one side of a substrate, which is passed between a cooling roller A and a rubber roller A. A porous film is stacked on another side of the substrate through a resin, and the substrate is passed between a cooling roller B and a rubber roller B. The cooling rollers A and B have surfaces with a ten-point average roughness (Rz) of 5 to 30 m and 0 to 20 m, respectively. The rubber rollers A and B have a rubber hardness (durometer (Type A)) of 60 to 95 and 50 to 80, respectively.

A recording medium according to one embodiment of the present disclosure includes a recording layer and an optical thin film. The recording layer includes a heat-sensitive color-developing composition and a photothermal conversion material. The photothermal conversion material absorbs a wavelength in an infrared region and generates heat. The optical thin film is provided on one surface of the recording layer. The optical thin film reflects the wavelength in the infrared region and transmits a wavelength in a visible region.

A reversible recording medium according to an embodiment of the present disclosure includes a first recording layer to be colored in a first color, a second recording layer to be colored in a second color, the second color being different from the first color, and a first intermediate layer provided between the first recording layer and the second recording layer, the first intermediate layer including a plurality of layers respectively containing materials different from each other.

The invention relates to a heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive colour-forming layer, which contains at least one colour former and at least one phenol-free colour developer, characterised in that the at least one colour developer is the compound of formula (A), Ar(NHCONHCONHAr.sup.1).sub.n (A), wherein Ar is an unsubstituted or substituted phenyl or naphthyl group, Ar.sup.1 is an unsubstituted or substituted phenyl, naphthyl, pyridyl, thiazolyl or benzothiazolyl group, and n is 1 or 2.

The invention relates to a heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive colour-forming layer, which contains at least one colour former and at least one phenol-free colour developer, characterised in that the at least one colour developer is the compound of formula (A), Ar(NHCONHCONHAr.sup.1).sub.n (A), wherein Ar is an unsubstituted or substituted phenyl or naphthyl group, Ar.sup.1 is an unsubstituted or substituted phenyl, naphthyl, pyridyl, thiazolyl or benzothiazolyl group, and n is 1 or 2.

A plastic material is useful as an ink receiver or printing medium in dye diffusion thermal transfer printing, wherein the plastic material has a polyamide component (a), and a (co)-polyamide (b) based on ether units and amide units. This plastic material can be used to make a layered structure. The layered structure can be used in dye diffusion thermal transfer printing. A security and/or valuable document with the layered structure can be obtained. Based on the finding that the (co)-polyamide (b) offers sufficient absorbency for the printing ink, the layer produced from the plastic material can be printed on by means of dye diffusion thermal transfer printing with a good color intensity.