Causes of ink blockage and its influencing factors

Ink drying is basically caused by the following points: The old printing was not cleaned. The solvent is drying too fast (the printing speed does not match the evaporation rate of the solvent). Dry hot air hit the board. When the contact points of the doctor blade and the plate surface are mixed with dust, moisture, air bubbles, etc., the ink transfer rate will decrease due to the decrease of the actual ink volume in the cell site. Some coarser particles may even be embedded in the cell site. . At the time of plate making, the precision and angle of the electric carving of the cell site will also be affected. The transfer to the ink causes the network to be insufficient or missing. The quality of inks and solvents is also one of the causes of blockage. If the fluidity of the ink is not good, the printing viscosity is too high, the ink has deteriorated or mixed with different series of inks, an inappropriate solvent or solvent ratio is used, and even the addition Improper handling of solvent inks can affect the transferability of the ink and cause blockage.

The effect of active particles: When printed for a certain period of time, the ink produces many reactive groups that bind to the chromium ions of the plate roller. When these binders are in the shallow part of the graded version, their binding force hinders Ink transfer to the substrate, resulting in block version, the basic performance is: shallow screen version of the flower. To solve these problems, we can add a slowing agent (such as CHY-1 printing aid) to the ink. Leakage is mainly caused by the pressure roller, film, improper operation and other reasons: the roller is uneven or there is a bubble will cause serious leakage phenomenon. Film corona or contaminated during use, causing localized corona insufficiency. The amount of ink in the ink tank is insufficient, and the printing roller has a partial lack of ink. A hard object stuck under the printing blade, scraping off the ink and causing the ink mark scraper. Imprinting due to blocking or ink loss. There are many reasons for the adhesion and peeling of the ink. Everyone generally considers the ink, film, and solvent residues, ignoring the mismatch between the temperature and the air volume during drying, the false drying phenomenon caused by the low temperature and high air volume, and insufficient cooling of the printed film after drying. These two points.

European and American countries have higher requirements for solvent residues, and the benzene content is generally not more than 0.5 mg/m2. With the current printing level in our country, it is very difficult for the benzene content to be lower than 2mg/m2. The residual solvent mainly exists in the process of printing and dry recycling, while the benzene solvent is mainly caused by printing residue (if the drying path of the dryer is long, the drying capacity is sufficient, and sometimes the printed residual solvent is volatilized. Therefore, we are now mainly discussing printing solvent residue problems.