(1) Surface treatment of printing plates. Gravure is now mostly electronically engraved. During the carving process, many small burrs are formed on the edge of the engraved mesh cavity. These small burrs also damage the squeegee during the printing process, causing the wire drawing. However, this type of drawing is limited to the dots on the printing plate and will not extend into the blank space. The new version is prone to this situation. Within a certain range, with the increase in the number of prints, drawing will gradually decrease. This requires that in the production process of the plate cylinder, on the one hand, the hardness of the engraved copper layer should be ensured, the formation of small burrs in the engraving process should be reduced, and the copper layer should be processed after the engraving; on the other hand, a standardized chromium layer should be established. Polishing process, including the type of belt used, the speed of the platen, the frequency of the polishing head, and the speed of movement. Polishing time and so on. If wire drawing occurs during the printing process, the surface of the printing plate can also be polished with 2# metallographic sandpaper or 600# water sandpaper or a dedicated nylon polishing net. Polishing can generally solve the drawing problem.
(2) Installation of printing plates. If the printing plate runs large during the printing process, it may also cause wire drawing. This requires checking the concentricity of the printing plate and the printing plate shaft (no shaft mounting plate to check the top), checking whether the bearing and transmission parts are deformed, worn, or even the machine base is horizontal.
2. Environmental wire drawing
The printing site environment must be kept clean. If there is dust in the operating environment, it may be mixed into the ink, resulting in drawing. Therefore, in the printing operation site, the number of people should be reduced as much as possible, and commuting should be performed in a clean and hygienic manner. Conditional companies can isolate the printing units, install air-conditioning facilities and dust removal equipment.
Drawing is one of the common problems in gravure printing, involving gravure printing machines, plate cylinders, doctor blades, and printing environments. Many factors such as ink, such as improper handling will affect the production and quality.
Drawing is also called pull line, starting line, when the ink performance and ink color is different, its performance is also different, usually black, blue. The drawing phenomenon of magenta is obvious, and it usually appears on a large area of shallow web.
The common wire drawing is mainly divided into three types: drawing in the shallow position, drawing in the squeegee in the solid color, and drawing in the blank in the printing blank.
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