Patent ID: 6305284
Filing Date: 2001-10-23
Classification: B41C

Abstract:
A method of making an offset printing plate, comprising:a blank plate attaching step of winding a plate-shaped blank plate having a heat sensitive layer to which an image is formed thermally on a support around an outer circumferential surface of a cylinder with the heat sensitive layer being directed outward, thereby making the blank plate rotatable integrally with the cylinder; andan image forming step of irradiating a group of beams comprising a plurality of infrared laser beams arranged in line to the blank plate on the outer circumferential surface of the cylinder based on an image forming signal while rotating the cylinder, thereby forming an image in accordance with the image forming signal to the heat sensitive layer of the blank plate;wherein, in the image forming step, the group of beams in line are irradiated to a single area on the blank plate; andwherein irradiation conditions for the plurality of infrared laser beams comprising the group of beams are determined individually such that the temperature of the blank plate is made uniform within the single area in which the image is formed at once by the group of beams in line.