| abstract |
The present invention discloses a negative planographicnprinting plate precursor for infrared exposure having an imagenrecording layer containing an infrared absorbing agent, anradical generator and a radical polymerizable compound on ansupport characterized in that a sensitivity ratio (S 1 /S 60 ) ofna sensitivity (S 60 ) when developed 60 minutes after infrarednlaser exposure to a sensitivity (S 1 ) when developed one minutenafter exposure is at least 0.5 and less than 1.0 in the imagenrecording layer. It is preferable that this compositionncontains a polymer compound which has a functional group havingnhigh radical reactivity and can be dissolved or swollen in waternor an aqueous alkali solution. |