The hottest overprint production process cycle

Overprint production process cycle

1. Pay attention to the technical control of paper cutting process. The accuracy of paper specifications directly affects the overprint accuracy of products. Because of different machine structures, their front gauge and pull gauge positions are not the same. In this way, if the edge of the paper is not cut squarely enough, and there are beveled edges or wavy edges, it will cause inaccurate overprint. This requires that the edges of the paper must be cut into right angles and straight lines for the products with glue convex combination, and there must be no beveled edges or wavy edges. In order to improve the cutting accuracy of paper, the thickness of cutting must be strictly controlled, because the thicker the paper stack is, the softer the paper is, the more severe the paper surface deformation is when the paper presser is pressed down. Therefore, the less the thickness of each stack is, the more conducive it is to improve the cutting accuracy of paper. In addition, the blade edge should also be kept sharp, and the appropriate blade angle should be selected according to the hardness of the paper, which is also an important measure to improve the cutting accuracy

2. Pay attention to the reasonable selection of the bottom support of the printing plate. The characteristics of the plate base material of the relief printing machine with circular flattening structure have a great impact on the printing pressure, overprint accuracy and ink quality. The traditional wooden bottom support is not solid, with poor squareness, flatness and stability. It is prone to bow and deformation, and the printing quality is difficult to guarantee. Therefore, relief printing should use solid, flat, square, stable aluminum or cast iron and other metallic materials, which is a reliable guarantee to improve the accuracy of overprint and ink quality

3. Pay attention to the rational use of paper. The paper is very sensitive to the temperature and humidity changes of the external environment, and has won many awards at the provincial and ministerial levels. Especially the paper just produced is most prone to expansion and variation due to the temperature and humidity changes, resulting in inaccurate overprint of products. In order to reduce the chance of this bad situation, the newly produced paper usually needs to be stored for about half a year after being transported back by the printing factory, so that the paper can be put into use after its characteristics are relatively stable, so it is not easy to have overprint problems. In addition, by hanging the paper, measuring the experimental temperature, friction force and calculating the friction coefficient, the cut paper can be placed in the printing workshop for several days, and then printed after balancing with the temperature and humidity of the printing workshop for a period of time, which is also conducive to the registration of products

4. Pay attention to the selection of appropriate printing plates. Letterpress printing process adopts copper plate, zinc plate, resin plate and other plates. Due to the different characteristics of printing plate materials, there are also obvious differences in their printing suitability and printing quality. According to the inkiness, ink transmission, gloss and pressure effect, resin plate performs best, copper plate takes second place, and zinc plate performs worst. In terms of the printing quality of dot, the printing quality of new energy-saving and sustainable building materials launched by dot BASF of copper plate is better, and the expansion rate of dot is also the least. Therefore, according to the characteristics of products, we should reasonably select plates for printing, so as to better improve the printing quality of products

5. Pay attention to the reasonable arrangement of printing color sequence. Reasonable arrangement of printing color sequence is an important measure to improve printing quality. Reasonable arrangement of printing color sequence should be considered from these aspects, that is, considering the arrangement of printing color sequence according to the characteristics of the substrate; Consider arranging the color sequence according to the differences in the structure of the printing machine; Arrange the color sequence according to the different graphic structure of the printing layout; Consider arranging the color sequence according to the color characteristics of the original; Arrange the color sequence according to the difference of ink characteristics; Arrange the color sequence according to the drying characteristics of the ink. This scientific and reasonable arrangement of printing color sequence can better improve production efficiency and product printing quality

6. Pay attention to the lining technology. Lining is the medium to realize pressure and imprint transfer. Its characteristics also affect the registration and ink quality of products. Therefore, the deformation coefficient of the lining material should be smaller, and the material should be neutral and hard. At the same time, the thickness of the lining must be determined in strict accordance with the technical parameters of the equipment specifications. In addition, the lining must be tightly wrapped and tight, and there must be no virtual looseness or bulging. Do not repeatedly patch or excavate on the lining to prevent inaccurate overprint and ghosting

7. Pay attention to adjust the appropriate printing pressure. The printing pressure should be adjusted evenly and moderately. Too much pressure is easy to stretch and deform the printing sheet, resulting in inaccurate overprint. Therefore, the appropriate printing pressure should be adjusted. The printing pressure should not be biased, so as to avoid the roughness and expansion of the edge of the printing page

8. Pay attention to master the overprint production cycle of products. After printing the previous color or several colors of the printed matter, those that can be overprinted should be overprinted immediately, so as to avoid stretching and variation of the printed matter due to too long delay, resulting in inaccurate overprinting and quality failure