Abstract: A heat-sensitive composition is disclosed which includes a substance which absorbs light and generates heat, an anionic self water-dispersible resin particle having an acid value of 10 to 300 and an average particle diameter of 0.005 to 15 &mgr;m, and a fluorine base surfactant. An original plate for a lithographic printing plate is disclosed which includes an ordinary negative- or positive-type PS plate having coated thereon the heat-sensitive composition. The original plate is image-wise exposed with high energy density light based on digital image information from a computer, subjected to first development with an aqueous alkali solution, flood exposure with active light, a second development with a developer for a negative or a positive, and post-treatment to obtain a printing plate.

Abstract: A spherically particulate toner characterized by a volume-average particle diameter of from 1 to 6 &mgr;m, a colorant content of not less than 9.1% by weight, particularly not less than 5% by weight when the colorant is an organic chromatic pigment, based on the total weight of the binder resin and colorant used and an average circularity (average of circularity defined by (perimeter of circle having the same area as the projected area of particle)/(perimeter of the projected image of particle)) of not less than 0.98. The spherically particulate toner according to the present invention gives an excellent image quality and can be consumed in a drastically reduced amount per sheet of printing paper. By predetermining the particle size distribution of spherical toner particles and the added amount of inorganic oxide fine particles to optimum values, the image quality can be further improved.