Introduction of gravure printing machine
The main feature of the gravure printing machine is that the graphic part on the printing plate is concave and the blank portion 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 is formed into a blank, and the concave portion is filled with the ink, and the deeper the recess is, the thicker the ink layer is. 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.
Gravure printing 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.
What are the main structures of gravure printing machines?
The mechanical editor tells you that the main structure of the gravure printing machine consists of five parts: paper feeding, ink feeding, printing, drying and delivery.
1. In the paper feeding section, the sheet-fed gravure printing machine is a paper-stack type continuous feeding, and the web-fed gravure printing machine continuously feeds the paper by a web.
2. The arrangement of the plate cylinder and the impression cylinder in the printing part is vertical, horizontal and inclined, and the plate cylinder is arranged below. Generally, each unit has one plate cylinder and one impression cylinder. In order to increase the printing pressure, some are equipped with two impression cylinders.
3. The ink supply device of the gravure printing machine has a direct ink supply for immersing the plate cylinder portion in the ink tank and an indirect ink supply for transferring the ink to the plate cylinder by the ink discharge roller immersed in the ink tank, and the high speed machine has The inkjet method is also used.
4. The drying part of the gravure printing machine is hot air heated by electricity or steam, and some use infrared or far infrared light to make the printed matter dry.
5. In the delivery section, the sheet of paper is piled up into a stack of paper, and the web is piled up and folded into a paper roll. There are two types of structure, the organic type and the satellite type, in the printing part of the multi-color gravure printing machine. The former is to set the unit according to the required color number. Each unit has one plate cylinder and one or two impression cylinders, and the delivery part adopts the rewinding method. The satellite type four-color gravure printing machine has a large impression cylinder and four sets of plate cylinders in the printing section. Gravure printing is also combined with lithographic or letterpress printing, die cutting, etc. to suit the different requirements of the printed matter.