Mysterious printing label ink
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Mysterious printing label ink (1)
With the development of the economy, the wide application of labels on commodities has driven the rapid development of the label printing industry. However, people's understanding of label printing inks is far less than the understanding of label materials, printing methods, etc. Label printing inks, such as a mysterious field, are waiting for us to recognize and explore.
There are many types of label printing inks, which can be divided into three categories according to the solvent used: water-based label printing ink, solvent-based label printing ink and UV label printing ink: (1) water-based ink is safe, hygienic, non-polluting, and meets environmental protection requirements. Conducive to human health; but there are also shortcomings, such as slow drying speed, low color saturation, poor stability, etc., it is not suitable to print large areas of the field, prolonged precipitation and stratification. (2) Solvent-based label printing ink has strong adaptability to label materials, stable performance and high printing quality; however, there are environmental pollution problems, and some volatile solvents are harmful to the human body. (3) UV label printing ink has excellent performance, reliable quality and wide application range; however, the price is high, and special drying equipment is required, and there are certain requirements for supporting materials.
When selecting the label printing ink, it is necessary to comprehensively consider the type of printing material, printing method and printing conditions, customer's special requirements, post-press processing, label use, use conditions, cost and other factors. The performance of label printing inks mainly includes hue, fineness, saturation, gloss, adhesion, viscosity, dryness, etc. These properties have an important influence on the printing process and printing quality.
The influence of the printing shop environment on ink performance and printing quality is mainly reflected in the following two aspects:
(1) The viscosity and dryness of the ink are sensitive to the ambient temperature, the temperature is increased, the viscosity of the ink is lowered, and the drying speed is increased;
Conversely, the viscosity of the ink increases and the drying speed becomes slower. In addition, the ambient humidity also has an effect on the drying of the ink. The humidity in the workshop is too high to be detrimental to the drying of the ink; if the workshop is too dry, it is easy to cause printing failure due to static electricity.
(2) The sanitary condition of the printing workshop is also very important. Therefore, the printing workshop should be kept clean, dust-free, and well ventilated.
In the printing process, problems such as poor ink adhesion fastness, poor ink drying, ink layer adhesion, bubble, paste, dry plate, poor ink transfer, color shift, etc. are often encountered. The analysis of these failures is as follows:
(1) Ink adhesion fastness is poor. Reason: The surface tension of the printing material is too low, the ink does not match the type of printing material, and the ink performance is poor. Solution: Surface treatment of the printing material, adding a wetting agent to reduce the ink tension and replace the ink.
(2) The ink has poor drying properties. Cause: Inappropriate ink solvent ratio, printing speed is too fast, and the ambient humidity is too high. Solution: adjust the solvent ratio, reduce the printing speed, increase the drying temperature, and reduce the environmental humidity.
(3) The ink layer is stuck. Cause: The ink is poorly dried, the ink is too soft, the printing pressure is too high, and the ambient humidity is too high. Solution: adjust the ink solvent ratio, add appropriate amount of anti-adhesive agent, increase drying temperature, reduce printing pressure, reduce environmental humidity and so on.
(4) Bubbles. Cause: The ink contains air, the surface tension of the ink is too large, the ink viscosity is too low, and the printing speed is too fast. Solution: Add appropriate amount of defoamer, adjust ink viscosity, and reduce printing speed.
(5) Paste plate. Cause: The ink pigment particles are too thick, the ink viscosity is too high, the amount of ink is too large, and the printing pressure is too high. Solution: replace the ink, properly reduce the viscosity of the ink, reduce the amount of ink, and reduce the printing pressure.
(6) Dry version. Cause: The ink drying speed is too fast, the drying temperature is too high, and the printing speed is too slow. Solution: adjust the ink solvent ratio, properly reduce the drying temperature, and increase the printing speed.
(7) Poor ink transfer. Cause: The ink does not match the type of the substrate, the ink viscosity is too high, and there is static electricity. Solution: Replace the ink, adjust the viscosity of the ink, and add an antistatic agent.
(8) Color shift. Reason: The ink hue is deviated, the ink drying speed is not suitable, the ink stability is poor, the performance of the printing material, the printing process is changed, and the like. Solution: replace the ink, adjust the solvent ratio, adjust the printing process parameters.
(9) Static electricity. Cause: The ink is too thin, the printing speed is too fast, the environment is too dry, and so on. Solution: Add antistatic agent, increase ink viscosity, reduce printing speed, adjust environmental humidity, etc.
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Mysterious printing label ink (2)
In the printing process, you should also pay attention to the following issues:
(1) Use the same brand of ink produced by the same ink manufacturer to avoid printing failures of different manufacturers and different types of inks.
(2) The ink is thoroughly stirred before use, and it is also frequently stirred during the printing process to ensure uniform dispersion of the ink system.
(3) The ink to be dispensed should not be too much each time, and the principle of “less plus, diligent addition” should be followed, which is beneficial to the stability of ink performance and can effectively avoid waste. In addition, for spot color ink, it should be well prepared. recording.
(4) In the printing process, in order to ensure the quality of the label print and the smooth production of the label, some additives such as antistatic agent, defoaming agent and detacking agent should be added to the ink. Within the specified range.
(5) There are many shortcomings in label printing inks on the market. The most prominent problem is the problem of ink hue deviation:
On the one hand, the hue of the same kind of ink produced by different ink manufacturers is different; on the other hand, even if the same kind of ink produced by the same manufacturer has different batches, the hue will be biased, sometimes even large. For this reason, the printing plant often has to stop the debugging, which is very unfavorable to the stability of the printing quality, which brings great inconvenience to the production and seriously hinders the improvement of the quality of the printed matter.
There is still a certain gap between domestic inks and imported inks, especially in high-end products. Domestic ink manufacturers should improve their technical level and production capacity as soon as possible, and drive the improvement of the entire ink manufacturing industry. In order to achieve better preservation results, the label printing ink should be stored in a closed container in a normal temperature, cool, dry, dark, and ventilated environment.
The following issues should also be noted during the storage and management of label printing inks:
(1) Safety first, keep the ink as far away as possible from fire sources and heat sources to prevent accidents.
(2) It is best to keep the temperature in the ink warehouse, which is not too different from the temperature in the printing workshop. If the temperature difference between the two is large, the ink should be put into the printing workshop in advance, which not only helps the stability of the ink performance, but also ensures the high efficiency of production.
(3) In some areas in the north, the winter is relatively cold, and the ink should be stored outdoors to prevent the ink from gelling at low temperatures. If gelation occurs, transfer it to a warehouse with a high temperature, or put it in hot water to restore the insoluble matter.
(4) In the ink storage and management, the principle of “first in, first out” should be followed, that is, the ink purchased first is used first to prevent the ink from affecting the use effect due to the long storage time.
(5) The ink also has a certain shelf life. If the storage is too long, various components in the ink may separate and precipitate. Therefore, the ink should not be stored for a long time, and the general shelf life is preferably 1 year.
(6) The remaining ink after printing must be sealed and stored in the dark. It must be filtered with a filter of 100 mesh or more before being reused. After thorough mixing, it can be mixed with the new ink.