Relationship between maximum temperature and humid

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Relationship between temperature and humidity and ink characteristics

ink is one of the important materials in printing production, and its characteristics largely determine the printing quality of products. However, in addition to the inherent conditions of its components, the changes of temperature and humidity also affect the characteristics of his keynote speech "industrial IOT helps realize smart factory", which has been fully proved by the production process practice

we know that the interaction between printing paper and ink is based on the form of adhesion and adsorption. This feature shows that the adhesion, cohesion, color brightness and other factors of ink greatly affect the printing quality of products. The temperature change of the production environment directly affects the viscosity and cohesion of the ink. In the printing production practice, we can find that when the printing environment temperature is too low, the molecular movement of the ink binder is slow, and the ink is easy to be solidified. In this way, its cohesion is large, and the fluidity of the ink is poor. In the printing process, there will be poor ink transmission and uneven ink distribution, which will affect the uniformity of the printing ink layer coating. On the other hand, due to the cohesion of the ink, its consistency is correspondingly large. The viscosity of ink with high consistency is obviously large, so it is very easy to cause defects such as paper powder, paper wool and coating layer pulling off the paper surface during the printing process, and lead to chain printing quality failures such as plate pasting, printing fuzzing and thickening. If the temperature is too high, the ink will become thin, the coloring power will decline, the ink color of the printed matter will appear pale, the color is not bright, and the printing quality will decline

in addition to the influence of the production environment temperature on the ink characteristics, the printing speed of the machine will also affect the ink characteristics. This is because the ink has the characteristics of "thixotropy". When the printing press is running at high speed, the friction coefficient of each ink roller (including the ink bucket iron roller) when it rotates at high speed is large. The heat generated by the roller body can dilute the ink, increase the fluidity and significantly reduce the coloring force. Based on this situation, when allocating ink, we should fully consider the printing speed of the machine used, and reasonably adjust the thickness of the ink, so as to better ensure the printing ink quality. Obviously, only maintaining a proper and constant temperature is an effective measure to prevent the change of ink consistency and viscosity. In addition to the influence of the above conditions, there are also operational factors, such as whether the pressure adjustment of ink roller and pad plate is appropriate or not, which are often ignored by operators who lack production experience. According to the author's previous process practice experience, the contact pressure between the rubber roller and the inking iron roller is too tight, the relief plate pad is too high, resulting in too tight contact with the inking roller, placing it in a dry place, and the gap between the ink bucket steel plate and the iron roller is too small, resulting in the excessive rotation stroke of the ink bucket iron roller, which will greatly increase the heat of printing friction and increase the ink thinning fluidity. Therefore, in order to reduce the temperature rise caused by abnormal friction and reduce the chance of ink variation, the cot body must maintain good roundness. If the roll head and bearing are worn or damaged, they should be repaired in time to maintain a uniform and appropriate contact pressure between the cot and the inking iron roll. A 0.05mm thick plug gauge can be used at the production site to check whether the contact is appropriate, That is to say, the plug gauge is inserted between the rubber roller and the inking iron roller for pulling, with a slight resistance. The height adjustment of the printing plate shall not be significantly higher than the technical parameters of the equipment specification, so as to maintain uniform and appropriate contact conditions with the inking roller. If the layout is not very large, do not adjust the rotation stroke of the ink bucket iron roller to "maximize" for ink delivery. Through the control of these operation techniques, the abnormal temperature rise during machine printing can be better prevented and the stability of ink characteristics can be ensured

from the above, it can be seen that the influence of temperature on the ink is mainly manifested in that it can change the thinness, fluidity and coloring power of the ink. The influence of humidity on ink performance is reflected in the dryness of imprinting. The production process shows that the printing ink layer dries slowly when the humidity of the printing environment is high. On the contrary, if the environmental humidity is low, the printing ink layer will dry quickly. Because the air humidity of the printing environment is high, and the moisture content of the printing paper is also high, these will be one of the reasons that affect the drying of the ink layer. Here, for example, the relative humidity is 65% and 75% respectively when the environment temperature of the new era in the field of materials is between 20 ℃ and 25 ℃. The printing results of the two production conditions show that the drying speed of their ink layers is up to 1 ~ 2 times the difference. It can be seen that the temperature has a greater impact on the ink than the temperature. Therefore, it is particularly important to do a good job in the humidity control of the production site

in view of the impact of temperature and humidity changes in the production environment on the ink and printing, in the absence of air-conditioning equipment, to reduce the impact of temperature and humidity changes on the ink and ensure the ink quality of color printing and the accuracy of overprint, the best measure is to place the prepared ink at a temperature between 20 ℃ and 25 ℃ a few days before printing, so that the ink can be balanced at a temperature and humidity suitable for the printing conditions for a period of time, The printing thixotropy of the ink is controlled within the "minimum" range to improve the printing quality and process effect of the product

to sum up, it is of great significance to correctly understand the impact of temperature and humidity changes on ink characteristics and take corresponding process technology and operation technical measures to control, so as to effectively avoid the main blindness in production, prevent the occurrence of various quality problems or ills, and improve the quality of products in the future

source: printing world by Kang qilai

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