オフセット印刷版の技術変遷

抄録

In the field of offset printing, especially in the pre-pressing process, digital technology has advanced significantly over the last 30 years. The old analog photolithography technology was transformed into desktop publishing (DTP) and computer to plate (CTP). The DTP completes the process of collecting images and characters on a computer screen. CTP makes it possible to draw data directly on the plate with a laser. These technologies have made it possible to improve productivity, stabilize quality, shorten delivery times, reduce costs, and respond to the environment. With the progress of visible-light and infrared-light laser technology, several types of CTP have been developed and have undergone selection and segregation. Radical-polymerization-type violet-laser-compatible photopolymer plates and phase-change-type thermal positive plates have become mainstream in commercial printing. On the other hand, acid-crosslinking-type and radical polymerization-type thermal negative plates have become mainstream for long-run printing and newspaper printing. Subsequently, the CTP system, which requires a highly alkaline developer pursued further process simplification, cost reduction, and environmental load reduction, and advanced the development of CTP technology for simplified and zero processing. Currently, non-processed plates (on-press development method/radical polymerization type) exhibit improved performance levels, and the non-processed plates are becoming mainstream in CTP. This report outlines the technical contents of the CTP plate material of each method.