When printing on the gravure printing machine, the full plate of the plate cylinder is inked, and the ink of the blank part of the plate is scraped off by the squeegee to leave the ink of the graphic part, and then the paper is pressed, and the embossing roller is embossed on the back side of the paper. The ink of the concave portion is directly transferred to the paper surface, and finally the printed matter is piled up or rewinded through the delivery portion.
Features of gravure printing machine:
Gravure printing machine products have the advantages of thick ink layer, rich layers, strong three-dimensional effect, good printing quality, etc., mainly used for printing exquisite color pictures, trademarks, decorative items, securities and color newspapers. Due to the complicated plate making process, long cycle and environmental pollution of benzene-containing inks, the gravure printing machine has not been widely used in China. Therefore, measures such as improving the plate making process, shortening the plate making time, using non-polluting inks, reducing energy consumption, and reducing costs are being studied and improved.
The main feature of the gravure printing machine is that the graphic part on the printing plate is concave and the blank part is convex, which is opposite to the layout structure of the letterpress printing machine. When the machine is printing a single color, the plate is first immersed in the ink tank to roll, and the entire surface of the printing plate is coated with the ink layer. Then, the ink layer on the surface of the printing plate which is a blank portion is scraped off, the convex portion forms a blank, and the concave portion fills the ink, and the deeper the recess, the thicker the ink layer. The machine transfers the ink of the recessed portion to the printed matter by pressure to obtain a printed matter.
When printing multi-color, the overprint method or the indirect partial ink application method is adopted, so that the inks of various colors are distributed on the relevant parts of the surface of the printing plate according to the needs, and the basic printing principle of printing multi-color is the same as the printing monochrome. There are two main types of printing plates used in gravure printing machines, one is gravure, which is a photocopying plate; the other is an engraving plate. The engravings are engraved by hand, mechanical and electronic engraving.
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