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Offset printing technology experience - water ink balance 13 points

water ink balance 13 points in offset printing note

offset printing uses the principle of oil-water immiscibility to balance ink and water on the printing plate, so as to realize point transfer. However, in the actual printing process, ink is from unstable to relative balance, and the heat is not reduced, and then from new imbalance to new relative balance. This relatively balanced process is a relatively complex and difficult work. Only by constantly summarizing experience in long-term production practice can we master its regularity

1. The printing plate must have a solid graphic foundation and blank foundation. The electronic universal experimental machine mainly adopts servo electromechanical as the power source to maintain its lipophilicity and hydrophilicity relatively stable. At the same time, the graphic foundation and blank foundation should have good adsorption on the printing plate foundation

2. The sand mesh on the surface of the printing plate must be kept uniform and fine, and have a certain mechanical strength

3. In principle, the workshop is required to be constant humidity and constant temperature, because the change of temperature will cause the change of ink viscosity and fluidity, so the ink loses balance, especially for resin ink. Generally, it is best to install air conditioners in the workshop and control the temperature within the range of 20~25 ℃

4. In production, it is best to keep the machine running at a normal constant speed and constant speed. The machine is fast and slow, which is easy to make the ink balance out of control

5. The performance difference between the ink and paper used in printing has a great impact on the parts that users can directly see. There are different requirements for using different paper and ink and mastering the balance of ink and water. For example, paper has tight texture, loose texture and water content; Ink has viscosity, fluidity and pigment particle size. Under the same conditions of printing plate, temperature and humidity, mastering the changes of their properties is the premise to ensure the balance of ink and water

6. The addition of dry oil in the ink accelerates the drying of the ink, but it also enhances the viscosity of the ink. Therefore, the improper amount of dry oil is the main factor that makes the ink balance out of control and dirty

7. The pH value of fountain solution is also the main condition that affects the ink balance and must be kept constant

8. The printing press must have accurate roller pressure, ink roller pressure and water roller pressure, which directly determine the balance of ink and water

9. When printing pictures and texts or text lines, the ink volume can be appropriately increased on the premise of ensuring that the final acceptance of the equipment is clear

10. Some inks have poor coloring power, and the printed products are dim and lifeless. In this case, the ink volume can be increased appropriately

11. The ink layer of single-sided printing can be thicker than that of double-sided printing

12. Coated paper and glass paperboard have smooth surface and low absorption, so the amount of ink should be smaller, especially when printing field graphics and texts, the amount of ink should not be too large

13. For thinner paper, the ink layer is not thick when printing, while for rough and absorbent paper, the ink volume can be enlarged