Silver-free black-and-white thermographic materials containing a benzoquinone and methods of imaging
AssigneeEastman Kodak Company
InventorsJoe E. Maskasky, Victor P. Scaccia
Life of this patent
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Abstract
Silver-free, aqueous-based direct thermographic materials are designed to have image tone with near neutral density. Without the use of organic silver salts containing reducible silver ions, the image is formed using a color developing agent precursor that releases a color developing agent when heated to a temperature of at least 80° C., a combination of cyan, yellow and magenta dye-forming color couplers that provide cyan, yellow, and magenta dyes, and a substituted or unsubstituted benzoquinone as an oxidizing agent. No silver metal or silver ions are purposely added to these materials. This combination of components provides a means for controlling image tone without reliance upon conventional toning agents.
Claims18
A silver-free, black-and-white thermographic material comprising a support having thereon at least one imaging layer comprising predominantly a hydrophilic or water-dispersible polymeric latex binder, and further comprising:
- a) a color developing agent precursor that releases a color developing agent when heated to a temperature of at least 80° C., and
- 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 magenta 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 a benzoquinone that is capable of oxidizing the released color developing agent,
- said material being substantially free of silver metal or reducible silver ions.
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.
Dependencies are inferred from the claim text.