Paper Printing Electrostatic Traceability

Paper is currently the most widely used substrate, how its performance directly affects the stability of production efficiency and product quality. Production practice shows that paper and ink have the same "thixotropic" side. The generation of printed static electricity is an inevitable manifestation of the variation of paper properties.

In the dry climate in winter, the opportunity for electrostatic phenomena in printed papers is obviously increased. Especially for products printed with non-coated paper, the electrostatic phenomenon is particularly severe in the case of fast printing speeds. The generation of static electricity not only causes the paper surface to absorb dust and paper, but also causes the papers to adhere to each other, causing great obstacles to normal paper feeding, paper splicing, and paper collection, which seriously affects the production efficiency and product quality. So, why does the paper produce static electricity? Why is the printing of static electricity on paper more frequent in the winter? We know that static electricity is caused by the friction of paper during the movement. The faster the printing speed of the machine, the more friction the paper and printer or the paper and the paper are in contact with each other, and the more serious the electrostatic phenomenon. The paper that produces static printed paper must have a significantly lower moisture content and should be measured with a rapid moisture analyzer. Some moisture content is less than 3%. It seems that the size of the electrostatic phenomenon (ie, the degree of electrification) is inversely proportional to the moisture content of the paper. This is because the drier the paper is, the greater its surface resistance is, and the static electricity caused by friction during the paper feeding process makes it difficult to generate a current. Stay in circulation. In this case, if the moisture content in the air surrounding the printing environment is high, the electrostatic charge on the paper surface will be quickly transmitted to the air to avoid failure. This shows that static electricity is not only related to the moisture content of the paper, but also closely related to the relative humidity of the printing shop. When the moisture content of the paper is less than 3% and the relative humidity of the printing shop is lower than 40%, the printing static electricity is easily generated. In particular, electrostatic faults are even more pronounced when the paper temperature is lower than the print shop temperature.

Paper moisture content, temperature and humidity in the printing shop, and high-speed frictional motion cause static on paper. In addition, when the paper is manufactured in a paper mill, the content of the electrolyte (such as sodium chloride, alum, etc.) is small, the sizing substance is too much, and the content of some fillers (such as kaolin, etc.) is less, then the paper is drying. In the process of drying and calendering, due to the effect and influence of high temperature and pressure, the paper is charged with high voltage static electricity. Improper storage of paper is also the source of printed static electricity. When there is a significant disparity between the temperature and humidity of the paper store and the temperature and humidity of the printing shop, the change in the moisture content of the paper causes printing static electricity; before the printing, the paper stacking time is too short and the stacking pile is too short. Pressure is too high, so that paper and printing shop lack of effective temperature and humidity balance time and pressure is too large and easy to produce electrostatic failure.

The electrostatic failure of paper printing can be solved by various methods. Through the implementation of preventive measures, the effect of eliminating or reducing static electricity can be achieved. The first is to adjust the temperature and humidity of the printing and paper warehouses so that they maintain a relative balance. Generally, the temperature is controlled between 18°C ​​and 20°C, and the relative humidity is maintained at 60% to 65%. If the paper is electrostatically charged, the workshop is relatively The humidity can be adjusted to between 80% and 85%. The second is to hang the paper. The thickness of the paper should be within 100 sheets per clip. The more loose the paper should be, the better the paper should be. In order to help the paper evenly absorb the moisture in the air to maintain a uniform water content on the paper; third is to install a static eliminator to the printing press, to eliminate static electricity by adjusting the voltage or high frequency; fourth is to reduce the printer The speed of the vehicle reduces the friction of the paper during the printing process and weakens the static electricity.

To sum up, taking all necessary precautionary measures will have a very important role in effectively preventing the occurrence of printing static electricity, which can not only eliminate static electricity but also ensure normal production and product quality.

Source: "Guangdong Printing"