Advantages and disadvantages of gravure image proc

  • Detail

Advantages and disadvantages of image processing for flexible packaging gravure printing

there are different opinions in the industry on whether flexible packaging printing adopts flexo printing or gravure printing. For dry and flexible packaging printing enterprises, they should fully understand their performance structure and take their advantages

up to now, it is still impossible to draw a clear conclusion. In today's upholstery industry, flexo printing and gravure printing are two very different printing processes. The ink transfer principle of flexo printing, whether it is two roller type, scraper type or integrated type, is basically composed of ink bucket, ink bucket roller, wrinkle roller and scraper. The ink is transferred from the ink transfer roller to the embossing roller, and then to the printing plate through the embossing roller. Through the pressure between the central embossing cylinder and the printing plate (satellite type), the image and text points of the printing plate stained with ink are printed to the surface of the substrate to complete the whole printing process. The ink amount is determined by the embossing roller. As flexo printing plate is made of soft rubber like polymer material, the image and text line points on the printing plate are embossed on the surface of the plate base, and the central impression cylinder is a rigid metal surface. The pressure between the two will cause the deformation of the image and text line points of the printing plate. This determines that the pressure must be very small, and the pressure variation range is only about 2kg/cm

on the other hand, the printed patterns are divided into field and hierarchical points. In order to make the field part flat and thick, the thick line roller (200 ~ 300 lines/towel) must be selected; The fine line roller (generally 600~1000 lines plus, at present, the laser engraving ceramic grain roller can reach 1200 lines/ten) should be selected for the layer point. Based on the analysis of the ink amount, the thick line roller is used in the field, and the hole volume is as high as 7.5~11.5bcm/sqin, referred to as BCM, while the fine line roller is used for the fine point, and the hole volume is only 1..7bcm/sqin, and it is combined with the hole opening and shape changes to solve the problem of the demand for ink amount

the pattern changes in a variety of ways, which leads to the ever-changing point hierarchy and brings about the problem of selecting the texturing roller: the slightly thick line roller will cause the small dots in the highlight part to fall into the ink hole and cannot be printed, and the "dumbbell shaped" dot paste; Too much detail makes the intermediate adjustment point appear thin and prone to color deviation due to insufficient ink amount, and the tone cannot be opened (the density line is unstable, and the point increase shows nonlinear changes, which is a major obstacle to the quality assurance of flexo printing). If the same color field and jingji'nan experimental machine factory slip and fall, which are the main reasons for shoe injuries, it is more difficult to solve the above contradictions. The first enterprise officially settled in the park, so the "eight color machine can only be six color machine" is helpless

when looking at gravure printing, it is directly inked by the printing plate or directly transferred to the printing plate by the inking roller. As the gravure plate is a rigid chrome plated metal roller, its image and text line points are composed of numerous pits in the shape of "holes". After inking, the ink on the surface of the plate roller except for the pits is scraped clean by the scraper, and then under the pressure of the impression roller (special soft rubber surface), only the ink in the pits is transferred to the surface of the substrate to complete the printing process. The thickness and density of the ink layer depend on the ink volume and transfer rate of the hole of the plate roller itself. The pressure between the embossing roller and the printing plate is much higher than that of flexo printing (about 40kg/cm). The adjustment range is large, and the control is relatively simple and easy. In high-speed printing, there is almost no worry about the expansion of the text line points. However, the disadvantage is that because the scraper scrapes and presses the plate surface continuously for a long time, although the plate is plated with hard chromium, it is still inevitable that the plate will be scratched, or because of the impurities and coarse hard particles in the ink, the cutting wires and lines in the printing process will be generated, resulting in defective printing, which will affect the printing quality

generally speaking, gravure printing reflects the level by the thickness of the ink and the density of the dots. All of us learn from the changes that have a significant impact on the price rise. Among all the printing process evaluations, gravure printing has the most open style level, and the thickness of the ink layer is about three times greater than that of flexo printing. The printing products are recommended as the brightest and brightest ink color, with the most distinct levels, so that other processes can catch up with it

Copyright © 2011 JIN SHI