HEAT DEVELOPING METHOD, HEAT DEVELOPING MACHINE AND HEAT DEVELOPABLE PHOTOSENSITIVE MATERIAL EACH USED IN SAME, METHOD FOR FORMING MASK MATERIAL AND IMAGE FORMING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a heat developing method in which the distortion and deformation of a photosensitive material due to heating are suppressed and the conveyability is improved even when processing time is shortened by increasing processing speed, unevenness in density between the right and left edges of the photosensitive material is suppressed and the deterioration of dot quality in the case of use for the production of a printing plate, scuffing in processing and the occurrence of surface ruggedness after heat development are prevented, to obtain a photosensitive material used in the method and the method to form a mask material. SOLUTION: A heat developable photosensitive material with at least silver halide, organic silver salt grains and a reducing agent on the substrate is heat- developed through three or more heating steps including a heating step A at >=115 deg.C, a heating step B at a lower temperature than that of the step A by 8-30 deg.C before the step A and a heating step C at a lower temperature than that of the step A by 8-30 deg.C after the step A.