Photothermographic material and image forming method using the same

1. A photothermographic material comprising a support, and an image forming layer provided on at least one side of the support, the image forming layer comprising at least a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent and a binder,

wherein:

(1) a silver iodide content of the photosensitive silver halide is not less than 40 mole %;

(2) the binder comprises a hydrophilic binder;

(3) the image forming layer comprises a silver iodide complexing agent; and

(4) the image forming layer comprises, as a silver carrier, at least one compound represented by the following Formula (I) or (II):

(wherein Q represents an atomic group that is necessary to form a 5 or 6-membered imide ring);

(wherein: R 5 independently represents a hydrogen atom, alkyl group, cycloalkyl group, alkoxy group, alkylthio group, arylthio group, hydroxyl group, halogen atom or N(R 8 R 9 ), where R 8 and R 9 each independently represents a hydrogen atom, alkyl group, aryl group, cycloalkyl group, alkenyl group or heterocyclic group; r represents 0, 1 or 2; R 8 and R 9 may be bonded to each other to form a substituted or unsubstituted 5 to 7-membered hetero ring; two groups represented by R 5 may be linked together to form an aromatic, heteroaromatic, alicyclic or heterocyclic condensed ring; and X represents O, S, Se or N(R 6 ), where R 6 represents a hydrogen atom, alkyl group, aryl group, cycloalkyl group, alkenyl group or heterocyclic group).

2. A photothermographic material according to claim 1 , wherein the silver iodide content is not less than 80 mole %.

3. A photothermographic material according to claim 2 , wherein the silver iodide content is not less than 90 mole %.

4. A photothermographic material according to claim 3 , wherein the silver iodide content is not less than 95 mole %.

5. A photothermographic material according to claim 1 , wherein the image forming layer comprises at least one selected from polyacrylamides and derivatives thereof.

6. A photothermographic material according to claim 5 , comprising a non-photosensitive organic silver salt formed into grains in the presence of the at least one selected from polyacrylamides and derivatives thereof.

7. A photothermographic material according to claim 1 , wherein the non-photosensitive organic silver salt comprises nano-grains.

8. A photothermographic material according to claim 7 , wherein a mean grain size of the nano-grains is in a range from 10 nm to 1000 nm.

9. A photothermographic material according to claim 1 , wherein the reducing agent comprises a compound represented by the following Formula (R):

(wherein: R 11 and R 11′ each independently represents an alkyl group, where at least one of R 11 and R 11′ is a secondary or tertiary alkyl group; R 12 and R 12′ each independently represents a hydrogen atom or a substituent that is substitutable on a benzene ring; L represents —S— or —CHR 13 —, where R 13 represents a hydrogen atom or an alkyl group; and X 1 and X 1′ each independently represents a hydrogen atom or a substituent that is substitutable on a benzene ring).

10. A photothermographic material according to claim 9 , wherein the hydrophilic binder comprises gelatin or a gelatin derivative.

11. A photothermographic material according to claim 10 , wherein a ratio by mass of the non-photosensitive organic silver salt to the binder in the image forming layer is in a range from 1.0 to 2.5.

12. An image forming method, wherein the photothermographic material according to claim 1 is exposed to light having a wavelength in a range from 350 nm to 450 nm.

13. An image forming method according to claim 12 , wherein the light having a wavelength in a range from 350 nm to 450 nm comprises laser light.

14. An image forming method according to claim 13 , wherein the laser light comprises light emitted from a semiconductor laser.

15. An image forming method according to claim 14 , wherein the semiconductor laser comprises a blue semiconductor laser.

16. An image forming method according to claim 12 , wherein the photothermographic material is thermally developed at a linear velocity of not less than 23 mm/second.