Printing system with a negative working thermal plate for onpress development

Method of printing on a press, said method comprising the steps of:

• image-wise exposing to infrared light a heat sensitive lithographic printing plate, wherein said lithographic printing plate comprises:
• a lithographic base with a hydrophilic surface thereupon, an image-forming layer including hydrophobic thermoplastic polymer particles and a hydrophilic polymer binder, and, an infrared absorbing compound, wherein said hydrophobic polymer particles contain more than 0.1 wt % of nitrogen and have an average particle size diameter in the range from 0.015 to 0.15 μm,
• developing the image-wise exposed printing plate by mounting it on a print cylinder of a printing press and applying an aqueous dampening liquid and ink to said imaging element while rotating said print cylinder, and
• printing.

Method of printing on a press, said method comprising the steps of:

• image-wise exposing to infrared light a heat sensitive lithographic printing plate, wherein said lithographic printing plate comprises:
• a lithographic base with a hydrophilic surface thereupon, an image-forming layer including hydrophobic thermoplastic polymer particles and a hydrophilic polymer binder, and, an infrared absorbing compound, wherein said hydrophobic polymer particles contain more than 0.1 wt % of nitrogen and have an average particle size diameter in the range from 0.015 to 0.15 μm,
• developing the image-wise exposed imaging element by mounting it on a print cylinder of a printing press and applying an aqueous dampening liquid and ink to said imaging element while rotating said print cylinder, and
• printing;
• with the proviso that said printing is at least 5 times longer than printing when said hydrophobic polymer particles contain less than 0.1 wt % nitrogen and have an average particle diameter more than 0.15 μm wherein said lithographic printing plate is present on said press prior to said image-wise exposing.