Some situations that should be noticed when printing gold ink

The main raw material of gold ink is brass powder, which chemically belongs to active metal and thus easily produces discoloration.

1. Gold ink can easily come into contact with air and water vapor to cause discoloration due to chemical reaction. Therefore, it is necessary to do a good job of storing the golden powder and avoid exposing it to the air. Unused gold powder should be tightly packed.

2. Because the chemical nature of gold powder is not stable enough, if it is in contact with acids, alkalis, carbon and sulfides, it will produce chemical changes of different degrees, which will greatly reduce its metallic luster, and gold ink will appear black. . Therefore, gold ink should be avoided for printing large-area domestic coated paper, offset paper, because the use of acid paper produced by the papermaking process is acidic, gold and ink after printing not only change color, but also lose luster;

3. Similarly, in the case of auxiliary materials for deployment of gold ink, auxiliary materials containing acid should not be used, but neutral materials should be used.

4, the use of metal should be mastered with the tone with the principle of printing, that is a deployment of the amount should be suitable for continuous printing about 3 hours, so as not to adjust the amount of too much gold powder in the grease for too long, and the air exposure to oxidation deterioration and loss of golden luster ;

5, the speed of gold ink printing should not be opened too fast, because the speed of the machine faster the ink roller friction heat increased accordingly, so easy to make gold ink oxidation black. Therefore, the speed of printing should be controlled at about 3,000 per hour;

6, offset printing gold fountain solution, should use a fountain solution containing alcohol or gum, in order to avoid the reaction of the acidic fountain solution and gold powder will make the ink dark and dull;

7, when printing gold should adjust the rubber roller, the position of each roller should be adjusted accurately, so as to avoid the poor ink transfer caused by the printing process piled up, so that the gold powder stays on the roller for a long time friction, causing gold ink oxidation Discoloration. In addition, the number of rubber rollers used should be used as little as possible to reduce the chance that the frictional heat will cause the blackening of gold;

8. The semi-finished products of printed gold ink should not be stacked too much. Otherwise, the heat released by gold ink during paper drying process cannot be emitted as soon as possible, and the gold ink will also be oxidized and discolored.

9, when the machine ink fountain, ink roller with kerosene, gas oil just cleaned, retained on the surface of the organic solvent has not completely evaporated, that is immediately carried out gold ink printing, so that gold ink and solvent reaction caused by discoloration;

10, if the gold on the background should pay attention to the appropriate addition of dry oil in the background, so as not to overprint the ink due to ink on the bottom, will affect the gold ink's gloss color.