Abstract: A thermosensitive image transfer medium is disclosed which consists essentially of (i) an image transfer sheet comprising (a) a plastic film, (b) an undercoat layer formed thereon containing a porous filler having an average particle size of 1 to 10 .mu.m and an oil absorption of 200 ml/100 g or less as measured in accordance with the Japanese Industrial Standard K 5101, with a depostion of the porous filler ranging from 1 g/m.sup.2 to 10 g/m.sup.2 and (c) an image transfer layer comprising a leuco dye formed on the undercoat layer, and (ii) an acceptor sheet having an acceptor layer comprising a color developer which is capable of inducing color formation in the leuco dye.

Abstract: A heat-sensitive recording medium including:(a) a transferring sheet which includesa first substrate,a lower layer provided over the first substrate and comprised of a discoloring agent and a solid ink having a first color, andan upper layer provided above the lower layer and containing a leuco-compound capable of coloring in a second color which is different from the first color by reaction with a developer at such a first temperature that at least one of said leuco-compound and said developer can melt but that neither the discoloring agent nor the solid ink can melt, the leuco-compound being incapable of coloring upon contact with the developer in the presence of the discoloring agent at such a second temperature that both of the discoloring agent and the solid ink can melt; and(b) a receiving sheet which includesa second substrate, anda developing layer provided over the second substrate and containing the developer.

Abstract: The present invention provides a heat-sensitive recording sheet which is composed of a support and a heat-sensitive layer formed on said support, said heat-sensitive layer consisting essentially of a color-developable substance and an organic acid substance capable of making said color-developable substance develop a color when heated and containing at least one member selected from the group consisting of condensate of higher fatty acid amide and formaldehyde and condensate of higher fatty acid and ethylene diamine and at least one member selected from the group consisting of vegetable waxes and mineral waxes.