The gravure printing machine adopts the direct printing method of circular pressing, the printing plate is directly made on the printing plate cylinder, and the ink is supplied by immersion or inkjet method, and there is no ink distribution mechanism. Due to the thick ink layer, the use of volatile fast-drying ink requires a drying device.
Bopp Bag Printing Machine
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 exactly the opposite of the layout structure of the letterpress printing machine. When the machine is printing a single color, the printing plate is first immersed in the ink tank to roll, and the entire surface of the printing plate is covered with ink. Then, the ink layer belonging to the blank part of the surface of the printing plate is scraped off, the convex part forms a blank, and the recessed part is filled with ink. The deeper the recess, the thicker the ink layer. The machine transfers the ink in the recessed part to the printed matter by pressure to obtain the printed matter.
When printing multiple colors, the overprinting 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 needed. The basic printing principle of printing multiple colors is the same as that of printing single colors. There are two main printing plates used by gravure printing machines, one is photogravure, that is, photocopying plate; the other is engraving plate. The engraving of the engraving plate includes manual engraving, mechanical engraving and electronic engraving.