Precautions for using solvent-based ink piezoelectric photo machine
Piezoelectric photo machine solvent-based inks are now used by many companies. Now, the music color printer manufacturer Xiaobian will summarize the things you need to pay attention to when using solvent-based inks:
(1) Solvent-based inks are dangerous and should be kept away from fire when stored. The printer often stores it in a basement or a low-temperature dangerous goods warehouse. In this case, the viscosity of the ink is high, and when the storage temperature is lower than 0 °C, the ink will gel. When the ink is taken out from the low temperature warehouse, it cannot be immediately poured into the ink tank, otherwise the performance of the ink cannot be properly exerted, which affects the quality of the printed matter. At this point, the ink should be returned to the temperature before use, and also pay attention to the temperature should not be too fast, to prevent the solvent volatilization ratio imbalance and affect the ink performance. It can be stored for a day and night after the same temperature as the printing shop.
(2) Solvent-based ink should be fully stirred before use, because some pigments will precipitate after long-term storage, resulting in inconsistent pigment content in the upper and lower parts of the ink, which affects the consistency of the hue before and after printing.
(3) The initial viscosity of solvent-based inks produced by ink factories is generally high, mostly in 30-40 seconds, up to 60 seconds. Before printing on the machine, the corresponding diluent should be used to reduce the viscosity of the ink, and the viscosity is controlled to about 25 seconds (25 ° C * coated 4 # cup). The viscosity is controlled to be non-dry, no imaginary edge, and not rough as the upper limit of viscosity, so that the print does not have water marks and the color is not thin as the lower limit of viscosity.
Also, be careful to use the same type of diluent as the ink used. Various types of solvent-based inks are equipped with special thinners. Because of their different composition, they must not be adjusted at will, so as not to affect the ink and not print properly.
In addition, the choice of thinner should also be combined with printing speed, dryer temperature, season and other factors. Taking solvent-based plastic film printing ink as an example, normal (medium speed) thinner should not be used in general. In summer, an appropriate amount (less than 5%) of n-butanol can be added to reduce the drying speed, and a quick diluent can be used in winter.
(4) In the printing, due to the different transfer properties of the colorant, the continuous material and the solvent on the substrate in the solvent-based ink, after a period of use, the solvent is volatilized due to the decrease of the resin content in the ink, and the ink becomes viscous and needs to be diluted. Adjust the agent, but control the amount of thinner. If the ink circulation system is not installed on the printing machine, it is not advisable to add too much at the time of adding the thinner. It is necessary to use a small amount, diligently, and stir while stirring to keep the ink uniform and consistent, and to prevent the ink structure from changing. Moreover, after adding a small amount of thinner, a part of the original ink should be appropriately adjusted to ensure the consistency of the color, gloss and the like of the printed matter.
(5) In the printing process, since the surface coating of the substrate is peeled off (especially paper material), it is easy to fall into the ink, causing the ink particles to become large. It has been found that the fineness of the ink will increase by more than 50 μm from the original 20 μm. These impurities are liable to cause printing failures such as cut lines and white spots. Therefore, the ink circulation system of the printing press should be reinforced to filter the ink and remove impurities.
(6) Different types of inks cannot be mixed and blended with each other to avoid deterioration of the ink. In particular, it is necessary to prevent misuse of the gravure ink and the flexographic printing ink, which affects the printing quality.
(7) The ink remaining after printing is stored in a sealed container after being filtered, and can be mixed with the same variety and the same color system for the next printing.
(8) The solvent-based ink is evaporated and evaporated, and the evaporation rate of the solvent is greatly affected by the ambient temperature and humidity, and the relative humidity is too low to generate static electricity. Therefore, the printing environment is preferably kept at a constant temperature and constant humidity. The general temperature is controlled at 25 ° C ± 1 ° C, and the relative humidity is controlled at 65 ° C ± 5% to reduce printing failure.
(9) Most of the solvents are flammable, explosive, and have certain toxicity, pollute the environment and endanger personal health. Therefore, production, use and storage should pay attention to fire prevention, explosion-proof, and use non-toxic or low-toxic solvents as much as possible, and use solvent recovery equipment to reduce environmental pollution.
