What is the working principle of a PS plate printing machine?

In the printing field, PS plate printing machines, as commonly used printing equipment, operate based on a series of precise processes. The PS plate, namely the pre-coated photosensitive plate, is the key carrier in the entire printing process.

The first step in the operation of a PS plate printing machine is plate making. The graphic and text information is precisely exposed on the PS plate through laser typesetting and other methods. The surface of the PS plate is coated with a layer of photosensitive material. During the exposure process, the part exposed to light undergoes a photochemical reaction, and its molecular structure changes, thus resulting in a significant difference from the unexposed part during development. After exposure, the PS plate undergoes development processing. The photosensitive layer in the unexposed part is dissolved and removed, while the photosensitive layer in the exposed part is retained, forming a clear image corresponding to the original text and graphics. At this point, the PS plate is completed.

Next comes the ink transfer stage. The PS plate is installed onto the plate cylinder of the printing press, and the plate cylinder begins to rotate. Ink is stored in the ink fountain of the printing press. Through devices such as the ink fountain roller and the ink transfer roller, the ink is evenly transferred to the printing plate cylinder. Due to the different ink adsorption properties of the image and non-image parts on the PS plate, the image part can adsorb ink because of the presence of the photosensitive layer, while the non-image part repels ink. In this way, the ink is precisely transferred to the graphic and text areas of the PS plate.

Then it enters the printing execution stage. The paper is conveyed between the impression cylinder and the plate cylinder of the printing press. As the cylinder rotates, under the effect of pressure, the ink in the graphic area on the PS plate is transferred to the surface of the paper, thus completing one printing cycle. To achieve continuous printing, paper is constantly fed into the printing press. By repeating the process of ink transfer and printing mentioned above, a large number of identical printed products can be produced.

The PS plate printing machine, through a series of closely coordinated steps including plate making, ink transfer and printing execution, takes advantage of the characteristics of the PS plate to accurately and efficiently replicate the graphic and text information on the original onto paper and other substrates, providing a reliable and widely used printing method for the printing industry.