Transfer sheets for thermal transfer recording

DETAILED DESCRIPTION OF THE INVENTION Then, the invention is described below in detail.
First, the dyes for use in this invention shown by formula (I) described above are explained.
In formula (I) described above, the alkyl group having 1 to 8 carbon atoms shown by R, R.
sup.
1, and R.
sup.
2 includes a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, etc.
, and they may be of a straight chain form or a branched form.
In these groups, alkyl groups having 1 to 6 carbon atoms are preferred and alkyl groups having 1 to 4 carbon atoms are particularly preferred.
The alkoxyalkyl group having 3 to 8 carbon atoms shown by R, R.
sup.
1, and R.
sup.
2 includes a methoxyalkyl group, an ethoxyalkyl group, a butoxyalkyl group, etc.
, and, in particular, an ethyl group substituted by an alkoxy group having 1 to 4 carbon atoms is preferred.
The aralkyl group shown by R, R.
sup.
1, and R.
sup.
2 includes aralkyl groups having 7 or 8 carbon atoms such as a benzyl group, a phenethyl group, etc.
Also, the hydroxyalkyl group shown by R, R.
sup.
1, and R.
sup.
2 includes an alkyl group having 1 to 4 carbon atoms substituted by a hydroxy group and, in particular, a hydroxyethyl group is preferred.
The alkylcarbonylamino group having 1 to 8 carbon atoms shown by X preferably includes alkylcarbonylamino groups having the alkyl moiety of 1 to 4 carbon atoms, such as methyl, ethyl, propyl, butyl, etc.
, and these alkyl groups as the substituents may be of a straight chain form or a branched form.
The alkoxycarbonylamino group having 1 to 8 carbon atoms shown by X includes alkoxycarbonylamino groups having the alkoxy moiety of 1 to 6 carbon atoms, such as methoxy, ethoxy, propoxy, hexyloxy, etc.
The alkylsulfonylamino group having 1 to 8 carbon atoms shown by X includes alkylsulfonylamino groups having the alkyl moiety of 1 to 4 carbon atoms, such as methyl, ethyl, etc.
, and, in particular, alkylsulfonylamino groups having the alkyl moiety of 1 to 2 carbon atoms are preferred.
Also, the halogen atom shown by X is preferably a chlorine atom