Silver-free black-and-white thermographic materials containing a benzoquinone and methods of imaging

A silver-free, black-and-white, non-photosensitive thermographic material that comprises a transparent polymer support having on only one side thereof one or more thermally sensitive imaging layers and an outermost non-thermally sensitive protective layer over said one or more thermally sensitive imaging layers,

• said one or more thermally sensitive imaging layers comprising predominantly one or more hydrophilic binders, and in reactive association, imaging chemistry consisting essentially of:
• a) a color developing agent precursor that releases a p-phenylenediamine color developing agent when heated to a temperature of at least 80° C., said color developing agent precursor being present in an amount of from about 0.001 to about 0.05 mol/m2,
• b) a cyan dye-forming color coupler that is capable of reacting with said released color developing agent to produce a cyan dye,
• c) a magenta dye-forming color coupler that is capable of reacting with said released color developing agent to produce a yellow dye,
• d) a yellow dye-forming color coupler that is capable of reacting with said released color developing agent to produce a yellow dye, and
• e) an oxidizing agent that is benzoquinone, tetrachloro-1,4-benzoquinone, 2,6-dimethoxy-1,4-benzoquinone, or 2,3,5-trichloro-6-pentadecyl-1,4-benzoquinone, and is present in an amount of from about 1 to about 10 mol/mol of said color developing agent precursor,
• said material being substantially free of silver metal or reducible silver ions, and said cyan dye-forming color coupler, magenta dye-forming color coupler, and yellow dye-forming color coupler being independently present in an amount from about 0.05 to about 0.5 mol/mol of said color developing agent precursor.