It is known from experience that the printing plate's resistance to printing can directly affect the economic benefits of production, while also reducing production costs, increasing production, and ensuring important conditions for printing quality. The main reason for the influence of printing plate printing durability is ink and environment. Let's analyze how it affects.
First, the influence of ink viscosity and drying speed on the printing plate
In the printing process, in order to scrape excess ink from the surface of the plate cylinder, the blade must penetrate the ink film, so when the viscosity of the ink we use is large, it needs to use a larger circle of blade pressure to scrape it. except. Therefore, the method we take reduces the viscosity of the ink during printing, so as to reduce the pressure of the blade to avoid the wear of the printing plate.
When the ink is excessively dried, the friction between the plate cylinder and the blade is relatively increased, and the life of the plate is less. When the environment is too wet, the dispersion of the ink is deteriorated, and the plate cylinder is not easily scraped. For this reason, the pressure of the blade has to be increased correspondingly, and the friction of the blade to the plate cylinder is correspondingly increased.
Second, the impact of hard sand, dust and other impurities on the printing plate
If the printed ink contains hard particles, the plate cylinder is easily scratched by hard particles when the ink is scraped, which affects the quality of the printed product, and causes the plate cylinder to be scrapped. Also, the impurities on the surface of the substrate are easily mixed into the ink. After a long period of accumulation, the plate cylinder is easily damaged. Therefore, it is particularly important to keep the substrate and the ink clean. Sometimes, in order to remove foreign matter, the ink in the ink tank may be filtered on time or the wire mesh may be inserted into the ink circulation system to continuously filter. Dust in the environment, whether it falls into the ink or adsorbed onto the impression cylinder, directly damages the blade and the layout.
Impurities, coarse particles, foreign matter, etc. in the ink are mainly caused by the following factors:
1. Admixture of foreign matter or ink in the ink is precipitated as the temperature changes, and the pigment is agglomerated to produce coarse particles.
2. Some foreign matter is carried by the film. When the film adsorbs dust due to static electricity and the additive in the film precipitates more into the ink, foreign matter is formed. Especially when the workshop is too dry, the film easily adsorbs dust due to static electricity, which in turn affects the life of the plate cylinder.
3. When using a pigment with a high hardness, the rule line may be caused even by kneading. If the pigment used in red, blue ink or the like is difficult to grind, the cut line is relatively easy to occur.
4. The drying system draws in dust or air ducts from the outside air for a long time.
Third, the impact of ink erosion
Some inks, such as black ink, are somewhat erosive to the plate cylinder, so they should be cleaned in time after use.
Fourth, the impact of chemical factors
A certain amount of active agent is added during the production process of the ink. If the activity of the ink or the plate cylinder is too high, the active material adheres to the plate cylinder relatively firmly during the printing process, and the blade is difficult to completely scrape. The blade pressure has to be increased to affect the life of the plate cylinder. At this time, the plate cylinder can be cleaned, and after the active material adhered to the plate cylinder is removed, a special surface-active slowing agent is added to the ink, and a remarkable effect is obtained. If a surfactant slowing agent is added before printing, it can prevent it.
Therefore, in the process of packaging box printing
, attention should be paid to the factors affecting the printing durability of the printing plate, and this will help to improve the quality, efficiency and cost of printing.