Abstract: The present invention provides a pyridine derivative represented by the following formula A or B, a dye produced by coupling the pyridine derivative A or B with an arbitray coupler and a thermal transfer sheet wherein use is made of the dye. In a thermal transfer process wherein use is made of a sublimable dye, the dye and the thermal transfer sheet according to the present invention can form a clear image having a sufficient density and an excellent light fastness.

Abstract: The present invention provides a pyridine derivative represented by the following formula A or B, a dye produced by coupling the pyridine derivative A or B with an arbitray coupler and a thermal transfer sheet wherein use is made of the dye. In a thermal transfer process wherein use is made of a sublimable dye, the dye and the thermal transfer sheet according to the present invention can form a clear image having a sufficient density and an excellent light fastness.

Abstract: A heat transfer sheet for use with a sublimation-type heat transfer printing method, capable of producing a high-quality image having high preservability, comprising a substrate sheet, and a dye layer which is formed on one surface of the substrate sheet, the dye layer containing a sublimable dye represented by the formula (I), (II), (III) or (IV) shown below.

Abstract: A thermal transfer sheet including a substrate sheet and a dye supporting layer formed on one surface of said substrate sheet, characterized in that the dye contained in said dye supporting layer is represented by the following general formula ##STR1## wherein R.sub.1 stands for a substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group or aryl group or an atom or atom group which combines with X to form a five- or six-membered ring; R.sub.2 stands for a substituted or unsubstituted alkyl group, a cycloalkyl group, an aralkyl group or an aryl group, provided that R.sub.1 and R.sub.2 may combine with each other to form a five- or six-membered ring which may have an oxygen or nitrogen atom; R.sub.3 stands for a hydrogen atom, a halogen atom, a cyano group, a substituted or unsubstituted alkyl group, cycloalkyl group, alkoxy group, aralkyl group, aryl group, acyl group, acylamino group, sulfonylamino group, ureido group, carbamoyl group, sulfamoyl group or amino group; R.sub.

Abstract: The heat transfer sheet according to this invention includes a substrate sheet and a dye carrier layer formed on one surface of said substrate sheet, and is characterized in that the dye included in the dye carrier layer is represented by the following general formula (I): ##STR1## wherein R.sub.1 -R.sub.4 and X each represent a substituent. According to this invention, it is possible to obtain image representations improved in terms of printing density and clearness as well as storability and resistance to discoloring and browning.

Abstract: A heat transfer sheet for use with a sublimation-type heat transfer printing method, capable of producing a high-quality image having high preservability, including a substrate sheet, and a dye layer which is formed on one surface of the substrate sheet, the dye layer containing a sublimable dye represented by the formula (I) shown below.

Abstract: A heat transfer sheet including (i) a substrate sheet, and (ii) a dye layer which is formed on one surface of the substrate sheet, and includes a binder and a sublimable dye represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different and may form together a five- or six-membered ring which may contain an oxygen atom or a nitrogen atom, are a substituted or unsubstituted alkyl, cycloalkyl, aralkyl or aryl group; R.sub.3 is hydrogen, halogen, a cyano group, or a substituted or unsubstituted alkyl, cycloalkyl, alkoxyl, aralkyl, aryl, acyl, acylamino, sulfonylamino, ureido, carbamoyl, sulfamoyl or amino group; R.sub.4 is hydrogen, halogen, a cyano group, or a substituted or unsubstituted alkyl, cycloalkyl, alkoxyl, aralkyl, aryl, acyl, acylamino, sulfonylamino, ureido, carbamoyl, sulfamoyl, amino, heterocyclic or sulfonyl group; R.sub.