Cause and treatment of blocking of the hottest gra

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Causes and treatment of gravure block up quality problems of block up in gravure printing are not uncommon. From production practice, we feel that the main reasons for this problem are as follows: first, the ink is dry; The popular methods in the advertising industry, such as "telling stories", citing non source statistical data and "scientific research shows", etc. the second is that impurities are mixed in the ink; Third, there are problems in plate making

1. the ink dries and solidifies in the layout

the roller of the electric engraving gravure printing plate is thin and has rich layers. The ratio of ink transfer in the layout varies depending on the type, viscosity, printing speed, etc. of the ink that must be stopped to remove sundries. Generally speaking, the ink in the hole is only transferred to the printing substrate. If the remaining part is dry and solid, it will encounter the scraper before the drum turns into the ink tank again and is not dissolved by the solvent, and the ink transfer rate will gradually decrease, resulting in blocking. This kind of fault is particularly easy to occur in the high temperature season in summer. Because the high temperature accelerates the volatilization of the solvent and increases the viscosity of the ink, the ink is easy to dry and solidify in the hole. If it is not cleaned in time with the solvent, it will also cause blocking. In addition, if the angle of the scraper is improper, the scraper is too far from the drum, the drum diameter is too large, and the printing speed is too slow, etc., it will cause blocking

the usual countermeasures are as follows:

1. Increase the printing speed as much as possible, or use slow dry solvent

2. Strengthen ink circulation

3. Clean the layout with solvent in time

4. Keep the ink at a certain concentration and viscosity. When printing for a long time, pay attention to adding solvents

5. In case of serious blocking, clean the plate with sliding powder after shutdown

6. Control and maintain the temperature and humidity in the workshop. To do this, it is necessary to install air conditioners in the workshop

2. impurities are mixed in the ink

impurities are mixed in the ink during the printing process, such as chips of the substrate, sand particles of the grinding scraper, dust adsorbed around due to static electricity or moisture in the air, which will cause blocking of the gravure plate. The ink can be filtered through the circulating pump

it is worth noting that some inks themselves may cause chemical reactions for some reason, resulting in blocking

3. problems in plate making

electric engraving intaglio is made by first electric engraving on the copper surface, then chromium plating, and then grinding to achieve the goal of rough polishing. In these processing processes, the ink transfer will be affected by the defects generated on the inner wall of the hole due to electric engraving, the surface defects left by chrome plating, and the burrs generated during grinding, which is also the reason for blocking. Especially in early 2015, blocking is particularly easy to occur in the highlight or small text of the print

Author: chenjinru, printing factory of Putian County, Fujian Province

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