1. Field of the Invention
This invention relates to a dry image forming material. More particularly, it relates to a dry image forming material which has good storage stability, whose sensitivity can be markedly increased by the heat treatment prior to the imagewise exposure to light and which can record images thereon only by dry processing.
2. Description of the Prior Art
Conventional wet processing photosensitive materials require a considerable skill in obtaining good results due to the complicated process of forming images thereon and further a lot of chemicals inconvenient in handling must be used in their processing. For this reason, in order to avoid these disadvantages there have been made many attempts to develop photosensitive materials capable of simplifying image forming process. For example, U.S. Pat. Nos. 3,152,904 and 3,457,075 describe photosensitive materials comprising an organic silver salt oxidizing agent, a reducing agent for silver ion and a catalytic amount of a silver halide which are photosensitive under normal light conditions and which can record images thereon only by dry processing. However, the storage stability of these photosensitive materials are markedly low. U.S. Pat. Nos. 3,802,888 and 3,764,329 describe photosensitive materials which are non-photosensitive under normal light conditions and which can be rendered photosensitive by the preliminary heating prior to the imagewise exposure to light. Although these photosensitive materials have good storage stability and can be advantageously handled under normal light conditions, their sensitivity is much lower than that of the photosensitive materials which are photosensitive under normal light conditions.