Mixture of dyes for cyan dye donor for thermal color proofing

In a process of forming a dye transfer image comprising imagewise-heating a cyan dye-donor element comprising a support having thereon a dye layer comprising a mixture of cyan dyes dispersed in a polymeric binder, at least one of the cyan dyes having the formula:

• ##STR30## wherein:
• R.sup.1 and R.sup.2 each independently represents hydrogen;
• a substituted or unsubstituted alkyl group having from 1 to about 6 carbon atoms;
• a substituted or unsubstituted cycloalkyl group having from about 5 to about 7 carbon atoms or a substituted or unsubstituted allyl group;
• or R.sup.1 and R.sup.2 can be joined together to form, along with the nitrogen to which they are attached, a 5- to 7-membered heterocyclic ring;
• or either or both of R.sup.1 and R.sup.2 can be combined with R.sup.3 to form a 5- to 7-membered heterocyclic ring;
• each R.sup.3 independently represents substituted or unsubstituted alkyl, cycloalkyl or allyl as described above for R.sup.1 and R.sup.2, alkoxy, aryloxy, halogen, thiocyano, acylamido, ureido, alkylsulfonamido, arylsulfonamido, alkylthio, arylthio or trifluoromethyl;
• or any two of R.sup.3 may be combined together to form a 5- or 6-membered carbocyclic or heterocyclic ring;
• or one or two of R.sup.3 may be combined with either or both of R.sup.1 and R.sup.2 to complete a 5- to 7-membered ring;
• m is an integer of from 0 to 4;
• R.sup.4 represents an electron withdrawing group;
• R.sup.5 represents a substituted or unsubstituted aryl group having from about 6 to about 10 carbon atoms or a substituted or unsubstituted hetaryl group having from about 5 to about 10 atoms;
• R.sup.6 and R.sup.7 each independently represents an electron withdrawing group;
• and
• R.sup.6 and R.sup.7 may be combined to form the residue of an active methylene compound;
• and at least one of the other of the dyes having the formula:
• ##STR31## wherein:
• R.sup.1, R.sup.2, R.sup.3 and m represent the same as above;
• X represents hydrogen, halogen or may be combined together with Y to represent the atoms necessary to complete a 6-membered aromatic ring;
• with the proviso that when X is hydrogen, then J represents NHCOR.sub.F where R.sub.F represents a perfluorinated alkyl or aryl group;
• and with the further proviso that when X is halogen, then J represents NHCOR.sup.8, NHCO.sub.2 R.sup.8, NHCONHR.sup.8 or NHSO.sub.2 R.sup.8 ;
• and with the further proviso that when X is combined with Y, then J represents CONHR.sup.8, SO.sub.2 NHR.sup.8, CN, SO.sub.2 R.sup.8 or SCN, in which case, however, R.sup.8 cannot be hydrogen;
• R.sup.8 is the same as R.sup.1 and R.sup.5 as described above;
• and
• Y is R.sup.1, R.sup.5, acylamino or may be combined together with X as described above.

In a thermal dye transfer assemblage comprising:

• a) a cyan dye-donor element comprising a support having thereon a dye layer comprising a mixture of cyan dyes dispersed in a polymeric binder, and
• b) a dye-receiving element comprising a support having thereon a dye image-receiving layer, said dye-receiving element being in a superposed relationship with said cyan dye-donor element so that said dye layer is in contact with said dye image-receiving layer, the improvement wherein at least one of the cyan dyes has the formula:
• ##STR32## wherein:
• R.sup.1 and R.sup.2 each independently represents hydrogen;
• a substituted or unsubstituted alkyl group having from 1 to about 6 carbon atoms;
• a substituted or unsubstituted cycloalkyl group having from about 5 to about 7 carbon atoms or a substituted or unsubstituted allyl group;
• or R.sup.1 and R.sup.2 can be joined together to form, along with the nitrogen to which they are attached, a 5- to 7-membered heterocyclic ring;
• or either or both of R.sup.1 and R.sup.2 can be combined with R.sup.3 to form a 5- to 7-membered heterocyclic ring;
• each R.sup.3 independently represents substituted or unsubstituted alkyl, cycloalkyl or allyl as described above for R.sup.1 and R.sup.2, alkoxy, aryloxy, halogen, thiocyano, acylamido, ureido, alkylsulfonamido, arylsulfonamido, alkylthio, arylthio or trifluoromethyl;
• or any two of R.sup.3 may be combined together to form a 5- or 6-membered carbocyclic or heterocyclic ring;
• or one or two of R.sup.3 may be combined with either or both of R.sup.1 and R.sup.2 to complete a 5- to 7-membered ring;
• m is an integer of from 0 to 4;
• R.sup.4 represents an electron withdrawing group;
• R.sup.5 represents a substituted or unsubstituted aryl group having from about 6 to about 10 carbon atoms or a substituted or unsubstituted hetaryl group having from about 5 to about 10 atoms;
• R.sup.6 and R.sup.7 each independently represents an electron withdrawing group;
• and
• R.sup.6 and R.sup.7 may be combined to form the residue of an active methylene compound;
• and at least one of the other of the dyes having the formula:
• ##STR33## wherein:
• R.sup.1, R.sup.2, R.sup.3 and m represent the same as above;
• X represents hydrogen, halogen or may be combined together with Y to represent the atoms necessary to complete a 6-membered aromatic ring;
• with the proviso that when X is hydrogen, then J represents NHCOR.sub.F where R.sub.F represents a perfluorinated alkyl or aryl group;
• and with the further proviso that when X is halogen, then J represents NHCOR.sup.8, NHCO.sub.2 R.sup.8, NHCONHR.sup.8 or NHSO.sub.2 R.sup.8 ;
• and with the further proviso that when X is combined with Y, then J represents CONHR.sup.8, SO.sup.2 NHR.sup.8, CN, SO.sub.2 R.sup.8 or SCN, in which case, however, R.sup.8 cannot be hydrogen;
• R.sup.8 is the same as R.sup.1 and R.sup.5 as described above;
• and
• Y is R.sup.1, R.sup.5, acylamino or may be combined together with X as described above.