Wuhan Handern printing operation technology
DATE：2021/2/4 8:39:44 / READ： / SOURCE：This station
Wuhan Handern printing operation technology
① Before loading the shuttle plate, you should know the product quality, color, material, check the specifications and dimensions, and check whether there are sand holes and scratches in the plate. In plate mounting, it is necessary to prevent the plate shaft from loosening, keep the plate running smoothly, and pay attention to the requirements of register color order, positive and negative printing plate, even clearance of through shaft pitch, flexible operation of plate roller, etc. Casting protective film unit www.handern.com② The correction scraper is an important part of the relief press which has a direct impact on the printing quality. Its main function is to clean the oil on the surface of the printing plate. The angle between the scraper and the printing plate is 30-60, which can keep the mouth from damaging the plate, and the printing base is better. If the angle between the scraper and the printing plate is too large, the knife is hard, the ink layer may be too thin, the printing ink gloss is poor, and the plate is easily damaged. On the contrary, the printed product has a certain gloss and ink layer thickness, but the image and text edge is easy to blur. The hardness and softness of the knife edge should be considered according to the depth of the four plate dot, the size of the pattern area, the thickness of the required ink and the order of color registration, as well as the performance of the printing material and the ambient temperature and humidity. The smoothness and smoothness of knife sharpening have a great influence on the prevention of "tail" like ink in the printing process.
③ Tension control adjusts the constant tension control system of unwinding and winding, and balancing the film tension is one of the keys to ensure the alignment. Theoretically speaking, the traction speed should be synchronized with the printing speed. However, due to the imbalance of unwinding and rewinding tension, especially in the process of printing heating and drying, the stretching speed should be 1 ~ 1.5% higher than the printing speed in order to ensure the accuracy of overprint and make the product specifications meet the requirements. Casting protective film unit www.handern.com
④ The use of diluent in the printing process, when the temperature, hot air volume, speed changes, in order to ensure normal production and product quality: need to use appropriate solvents to adjust, that is, the use of diluent. The diluent is usually a mixed solution composed of isopropyl alcohol, dimethylamine and 7-alcohol.
According to the drying rate, diluents can be divided into faster than type and slower than type. It is faster to reduce the proportion of erjialai or replace erjialai with Jialai, which is generally used in winter with low temperature. If the isopropyl alcohol in the mixed solution is removed and replaced by butanol or a small amount of cyclohexane is added, it is a slow drying type, which is generally used in summer with higher temperature.
⑤ The essence of printing pressure printing process is to transfer the pattern formed by the ink attached to the plate to the printed material. In the process of ink transfer, a certain pressure must be applied, that is, the so-called printing pressure. When other conditions remain unchanged, the transfer rate increases with the increase of printing pressure. When the printing pressure increases to a certain level, the ink transfer rate will not increase, and it will be harmful to increase the printing pressure. Therefore, from the perspective of ink transfer, the transfer point from improved state to balanced state is the appropriate printing pressure, that is, the necessary minimum pressure. See Figure 12-27.
⑥ The transfer of hot and cold air and temperature and humidity ink to plastic film depends on the convection evaporation and diffusion evaporation of solvent. In order to improve the drying speed, hot air should be combined with cold air to accelerate the diffusion, penetration and convection of solvent between ink film. That is to make the drying speed adapt to the release of solvent, the change of vehicle speed and the requirements of color registration. When printing multiple sets of stacked patterns, the ink thickness and drying speed of each set of colors are different. For example, the viscosity of the ink between the first set of colors and the subsequent sets of colors should be reduced one by one, and the first set of colors should be controlled in the state that the ink seems to be dry rather than dry. Ink drying too fast or too slow will occur after printing roller stick before printing roller picture and text phenomenon. Casting protective film unit www.handern.com
The temperature and humidity of the working environment affect the dryness and drying speed of the ink, so it has a great relationship with the quality of the finished product. It is reported that if the humidity is doubled, the drying speed will be delayed nearly twice, which will cause adhesion. Moreover, in polyamide ink, when the humidity is high, due to the evaporation latent heat of some alcohol solvents is high, when the ink film cools, due to the condensation of the surrounding water, the product will produce whitening phenomenon. On the contrary, low humidity will cause problems such as printing. The optimum temperature of printing workshop is 18 ~ 22c and humidity is 65 ~ 75%.
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