HEAT-SENSITIVE, NON-ABLATABLE WASTELESS IMAGING ELEMENT FOR PROVIDING LITHOGRAPHIC PRINTING PLATE HAVING DIFFERENCE IN COLORING MATTER DENSITY BETWEEN IMAGE AND NON-IMAGE REGIONS

摘要

PROBLEM TO BE SOLVED: To visually identify the image and non-image regions after an exposure by a method wherein an uppermost layer which forms hydrophobic and hydrophilic regions the same as an image by an exposure is included in a supporting body, and an IR-coloring matter which changes an optical density by the exposure of an image forming element is contained. ;SOLUTION: This image-forming element which is heat-snsitive and non-ablatable and wasteless for providing a lithographic printing plate includes and uppermost layer which can form hydrophobic and hydrophilic regions the same as an image by an exposure which is the same as the image, on a supporting body, and contains an IR-coloring matter which can change the density of the color by the exposure of the image forming element. For the IR-coloring matter contained in the image forming element, a mixture can be used, but it is preferable to use an IR-coloring matter of one kind alone. Preferably, the IR-coloring matter is an IR-cyanin coloring matter. Also, the uppermost layer or a layer which is directly under the uppermost layer preferably contains a compound which can convert light into heat. A suitable compound for this purpose preferably is an infrared ray absorbing component.;COPYRIGHT: (C)1999,JPO