There are many kinds of printed dew points, how to quickly identify and treat the symptoms?
There will be many quality problems in the production process of printing presses, such as printing paste, printing deinking, printing dew, etc., among which printing dew is a relatively common problem. In actual production, there are many reasons for printing whiteness. This article focuses on how the printing staff should quickly find the type of printing whiteness and take medicine.
Printing exposure seriously affects printing results
Printing whiteness is the most common and most difficult quality problem in the production of corrugated boxes. Printing whiteness seriously affects the printing effect, which will not only cause unattractive printing on the surface of the carton, but also cause large areas of whitening, it will also be regarded as unqualified products, resulting in waste in production.
Paper water absorption, ink viscosity, printing pressure, etc. will cause printing to be white
There are various reasons for the phenomenon of printing whiteness, such as paper water absorption, ink viscosity, printing pressure, paper dust on the cardboard, dust and so on. Of course, the reasons for printing disclosure are different, so the way to solve the problem is naturally different!
Different prints show different performance, and should be treated according to the disease!
As a printing staff, how to quickly find the solution direction of printing printing? Often the reasons for printing whiteness are different, and the appearance of the whiteness is also slightly different. The printing staff needs to learn to judge the crux of the printing whiteness according to the appearance, so as to quickly deal with it! The following highlights the three most common phenomena of exposure and solutions.
1. Exposure caused by improper pressure adjustment
1. The pressure of the plate pressure (up pressure) is not enough. The pressure of the printing cylinder and the anilox roller: the imprint on the cardboard has a concave and convex feeling
Insufficient pressure of the plate press (upper press). The whiteness is mainly reflected in the incomplete printing of the printed surface, the printed patterns are smooth and clean, and the printed patterns have imprinted marks on the cardboard. As long as the white areas are printed by hand, the cardboard here can be found. There is a feeling of unevenness, once this phenomenon occurs, it means that the plate pressure is insufficient. If you separate the printing unit and check the printing plate, if the amount of ink on the plate is insufficient, it is also the lack of pressure on the printing plate, which causes the printing to become white. Generally, the printing area will be larger.
2. Insufficient printing pressure (pressure of the pressure roller and printing cylinder): there is enough ink on the printing plate, no unevenness
The lack of printing pressure has the same effect as the lack of plate pressure, but there is a very obvious difference, that is, the printed pattern has no unevenness on the cardboard, and there is enough ink on the printing plate.
Improvement method: The best solution to these two types of whitening phenomenon is to adjust the respective pressure to an appropriate position, which can directly improve the printing whitening phenomenon.
Second, the ink viscosity is low and white: the color of the printed pattern ink is light, showing the phenomenon of pinholes
The phenomenon of printing dew appears when the ink viscosity is low. The most obvious thing is that the ink color of the printed pattern is lighter, and the printing dew shows a pinhole phenomenon, and the untrue printing pattern looks very virtual.
Improvement method: Firstly, the viscosity of the ink should be measured when such whitening occurs. You can add tackifier to the ink or add some new ink to solve the printing whitening phenomenon.
Third, the paper is exposed: the printing pattern is deinked
The phenomenon of printing whiteness caused by paper is mainly reflected in the deinking of the printed pattern. If the color block is white, it is mainly reflected in the middle part of the paper, because the paper has very poor ink absorption, the ink cannot penetrate into the paper, and the ink floats on the surface of the paper. As long as you rub it by hand, you will notice that the ink has fallen off.
Improvement method: If you encounter this kind of printing, you should not add printing pressure and plate pressure desperately. You must work hard from the ink side to increase the resin content and penetrant in the ink. This method is more effective than other methods.
Concluding remarks: The occurrence of printing white phenomenon and the solution of printing white phenomenon are far more than these aspects. The above four are just the most common printing white phenomenon in the production process.
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