| 摘要 |
PURPOSE:To obtain a heat developing material which prevents a thermal fog without using mercuric salt and has good developability by incorporating specific polyhydric alcohol in a photosensitive element layer contg. a chemically sensitized silver halide, org. silver salt, reducing agent and a hydrophilic binder. CONSTITUTION:The polyhydric alcohol expressed by the formula I (R<1>, R<2> are H, CH2OH or C2H4OH, n is 0-7) is added to the coating liquid for forming a photosensitive element layer consisting of active gelatin, photosensitive silver halide chemically sensitized by a sulfur sensitizer, etc., org. silver such as various kinds of benzotriazole silver, silver salt of aliphat. or arom. carboxylic acid, a reducing agent such as Na2S2O3 and a water soluble binder such as gelatin, whereby the dipersibility of silver salt, etc. in the aq. gelatin soln. is improved and developability is improved. A high density image is obtd. with high sensitivity without the need for using harmful mercuric salt in preventing a thermal fog. The developability is further accelerated by adding the mercaptotriazole compd. of the formula II, etc. |
