The gravure printing machine is a machine that performs printing using a gravure. The graphic portion of the printing plate is recessed, and the blank portion is on the same plane as the outer circle of the printing plate cylinder.
When printing on a gravure printing press, the entire plate surface of the plate is inked, and the ink on the blank part of the plate is scraped off with a squeegee to leave the ink of the graphic part, and then passed through the paper. The ink in the concave part is directly transferred to the paper surface, and finally the printed matter is piled up or rerolled by the receiving part.
1. The models are divided into single-sheet and web gravure printing machines according to the paper used. 2. According to the number of colors printed in one operation of the unit, it is divided into single color, four colors, five colors, six colors, etc. There are also single-sided printing and double-sided printing.
Gravure printing products have the advantages of thick ink layer, rich layers, strong three-dimensional sense, and good printing quality. They are mainly used for printing delicate color pictures, trademarks, decoration products, securities and color newspapers. Due to the complicated plate making process of the gravure printing press, the long cycle and the environmental pollution caused by benzene-containing ink, it has not been widely used in China. Therefore, measures to improve the plate-making process, shorten the plate-making time, use non-polluting inks, reduce energy consumption, and reduce costs are under study and improvement. The main characteristics of the gravure printing machine are that the graphic part on the printing plate is concave, and the blank part is convex, which is exactly the opposite of the layout structure of the letterpress printing machine. When the machine prints a single color, the printing plate is dipped in the ink tank and rolled, and the entire printing plate surface is coated with an ink layer. Then, the ink layer on the surface of the printing plate, which is a blank part, is scraped off, the raised part forms a blank, and the recessed part is filled with ink. The deeper the recessed part, the thicker the ink layer is. The machine transfers the ink of the recessed portion to the printed matter by the pressure, thereby obtaining the printed matter. When printing multiple colors, the overprint method or indirect partial ink coating method is adopted, so that the inks of various colors are distributed on the relevant part of the surface of the printing plate as required. The basic printing principle of printing multiple colors is the same as that of monochrome printing. There are mainly two types of printing plates used by the gravure printing machine, one is a photogravure, that is, a photocopying plate; and the other is a engraving plate. The engraving of the engraving version includes hand engraving, mechanical engraving and electronic engraving.