Black and white photothermographic material and image forming method

1. A black and white photothermographic material comprising at least a photosensitive silver halide, a non-photosensitive organic silver salt, and a binder on a support, wherein the black and white photothermographic material comprises a compound represented by the following formula (1), and further comprises a compound represented by the following formula (5):

wherein R 1 , R 2 , R 3 , and R 4 each independently represent a hydrogen atom or a substituent which substitutes for a hydrogen atom on a benzene ring; and R 5 represents an alkyl group, an aryl group, or a heterocyclic group;

wherein R 9 and R 10 each independently represent a substituent which substitutes for a hydrogen atom on a benzene ring; m represents an integer of from 0 to 4; n represents an integer of from 1 to 3; when m represents 2 or more, a plurality of R 9 may be the same or different from one another; when n represents 2 or more, a plurality of R 10 may be the same or different from one another; at least one of R 10 is an alkoxy group, an aryloxy group, an alkylthio group, or an arylthio group, and the ortho position of the anilino ring is substituted by any of these groups; and R 11 represents an alkyl group, an aryl group, or a heterocyclic group.

2. The black and white photothermographic material according to claim 1 , wherein the photosensitive silver halide has an average silver iodide content of 40 mol% or higher.

3. The black and white photothermographic material according to claim 1 , wherein the non-photosensitive organic silver salt comprises a silver salt of a long-chained fatty acid.

4. The black and white photothermographic material according to claim 1 , wherein the black and white photothermographic material comprises: at least one selected from compounds represented by the following formula (2); at least one selected from compounds represented by the following formulae (3) or (4); and at least one selected from compounds represented by formula (5):

wherein X and Y each independently represent a hydrogen atom or an electron attracting substituent; and R 6 represents an alkyl group, an aryl group, or a heterocyclic group;

wherein Z represents a hydrogen atom or a substituent; and R 7 represents an alkyl group, an aryl group, or a heterocyclic group;

wherein Z represents a hydrogen atom or a substituent; and R 8 represents an alkyl group, an aryl group, a heterocyclic group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, a sulfonyl group, a sulfamoyl group, or a cyano group.

5. The black and white photothermographic material according to claim 1 , wherein the black and white photothermographic material further comprises an ortho- or para-bisphenol compound.

6. The black and white photothermographic material according to claim 5 , wherein the ortho- or para-bisphenol compound is a compound represented by the following formula (R):

wherein R 11 and R 11′ each independently represent an alkyl group having 1 to 20 carbon atoms; R 12 and R 12′ each independently represent a hydrogen atom or a substituent which substitutes for a hydrogen atom on a benzene ring; L represents an -S- group or a -CHR 13 -group; R 13 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms; and X 1 and X 1′ each independently represent a hydrogen atom or a group substituting for a hydrogen atom on a benzene ring.

7. The black and white photothermographic material according to claim 6 , wherein, in formula (R), R 11 and R 11′ each independently represent a secondary or tertiary alkyl group.

8. The black and white photothermographic material according to claim 1 , wherein 50% by weight or more of the binder is a polymer latex.

9. The black and white photothermographic material according to claim 8 , wherein the polymer latex comprises a monomer component represented by the following formula (M) in a range of from 10% by weight to 70% by weight:

CH 2 =CR 01 -CR 02 =CH 2   Formula (M)

wherein R 01 and R 02 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a halogen atom, or a cyano group.

10. The black and white photothermographic material according to claim 9 , wherein, in formula (M), both of R 01 and R 02 represent a hydrogen atom, or one of R 01 or R 02 represents a hydrogen atom and the other represents a methyl group.

11. The black and white photothermographic material according to claim 1 , wherein the photosensitive silver halide has an average silver iodide content of 80 mol % or higher.

12. The black and white photothermographic material according to claim 1 , wherein the photosensitive silver halide has an average silver iodide content of 90 mol % or higher.

13. The black and white photothermographic material according to claim 12 , wherein the photosensitive silver halide comprises tabular grains.

14. An image forming method using the black and white photothermographic material according to claim 1 , wherein the image forming method comprises:

(a) providing an assembly for forming an image by placing the black and white photothermographic material between a pair of fluorescent intensifying screens;

(b) putting an analyte between the assembly and an X-ray source;

(c) applying X-rays having an energy level in a range of 25 kVp to 125 kVp to the analyte;

(d) taking the black and white photothermographic material out of the assembly; and

(e) heating the removed black and white photothermographic material in a temperature range of from 90° C. to 180° C. for an amount of time in a range of from 1 sec to 60 sec.