The full solution of printing ink gloss (below)

Third, printing pressure

Pressure is the key to a good transfer of prints. Pressure is too high, prints are enlarged, and glossiness is weakened; pressure is too small and prints are not clear, which can result in dull prints. Therefore, under the premise of ensuring that the ink on the blanket can be correctly transferred to the printing material during offset printing, the minimum pressure should be used as much as possible so as to print the glossy printing product.

Under the same paper and ink conditions, due to the problems in the operation process, the gloss of finished products often differs greatly after printing. Without considering the treatment of post-printing, the following methods can be used to increase the gloss of printed products:

1. Improve the acidic wetting fluid. Our country has used acidic wetting liquids for decades, mainly chromic acid and phosphoric acid. Although diluted, the pH is still between 3.5 and 5.6. The stronger the acidity, the greater the decomposition force and corrosive force on the ink binder and the pigment, resulting in rougher surface of the imprinted film and reduced gloss. For the research and development of wetting fluids, breakthroughs have been made in recent years. For instance, Shanghai's “Lydtex Wetting Powder” can be said to be effective. Now our country's offset wetting fluid has entered a new stage, but some printing The factory is still using the old formula.

2. Reduce the degree of ink emulsification. Excessive emulsification of the ink in offset printing is caused by large amounts of water and ink in the operation. The ink layer on the imprint looks very thick, but the ink molecules become oil-in-water, and after drying, the gloss is extremely poor, and a series of other malfunction. Water, ink and more is the most taboo practice in offset printing. To change this situation, in addition to the quality and technical education that should always be performed on operators, we recommend the use of "Lide wet powder," because the agent has better wetting properties. Even if the layout moisture is small, it is not easy to get dirty. It is both beneficial to the operation and makes the finished product glossy.

3. Appropriately add auxiliary agent in ink. Adding appropriate auxiliary agents in the ink can adjust the printability of the ink for smooth printing. Most of the auxiliaries have an adverse effect on the gloss of the finished product. For example: anti-adhesive agent, the main raw material for the six grain flour, adding ink, the surface of the imprinting film layer due to the precipitation of corn flour and rough, the finished product is poor. Another example is the addition of No. 6 thin varnish, which not only increases the fluidity, but also increases the permeability of the blot on the paper, and also reduces the drying, which is detrimental to the gloss of the print. Therefore, the amount of ink added to the general adjuvant must not exceed 5%. If the gloss effect is taken into consideration, it should be kept less or not. However, fluorocarbon surfactants are different. They can prevent surface defects such as orange peel and wrinkles in the ink layer, and at the same time, can improve the gloss of the surface of the printed product.

4. Use dry oil properly. For high-gloss, fast-drying inks, they have sufficient drying capacity under normal temperature and humidity conditions. In case of the following conditions should be added dry oil: First, in the winter when the temperature and humidity are low; Second, the ink must be added to the anti-adhesive agent, de-adhesive, thin ink, etc., should be added Dry oil. In the process operation, the correct use of dry oil is very beneficial to the gloss of the finished product. This is because it takes time for the paper to absorb the binder. During this process, the binder is condensed as quickly as possible until the conjunctiva is dry, which is the key to good gloss.

5. Pay attention to dusting. Dusting powder, like ink, can also produce cohesion, especially in bags or drums that are badly sealed. After dusting, the powder is condensed into larger particles and sprayed on wet ink blots to make the surface of the ink layer rough and reduce. The original gloss, so dust should pay attention to moisture. In addition, there is a heating device on the mechanism of the powder spraying device, which should be inspected when using powder spraying, and whether the heating device is malfunctioning.

6. Adjust the machine correctly. Whether or not the thickness of the ink layer is up to the standard also has an effect on gloss. For example, poor pressure regulation, high dot gain rate, and the thickness of the ink layer do not meet the standards, and the gloss of the finished product is slightly poorer. Therefore, we must adjust the pressure so that the expansion rate of outlets will be controlled at about 15%. The ink layer of the printed product will be thick, the layers will be pulled open, and the gloss will also be there.

7. Add Fan water (No. 0 oil). This oil is very viscous, thick in itself, can adjust the ink concentration, thicken the thin ink, increase the gloss of printed products.

8. Add bright light. Bright paste is processed from raw materials with high gloss, which can increase the gloss of the ink, but the amount should not be too large, otherwise it will reduce the drying speed of the ink, resulting in sticky, brushed phenomenon, affecting gloss.

9. Add a lighter. When some inks are too dark to meet the requirements of spot color printing, they need to be lightened. This will not only make the ink lighter, but also improve the gloss of the prints.

10. Add 19# resin oil. When the ink fluidity and transfer performance are not good, 19# resin oil can be directly transferred, which can not only improve the ink gloss, but also does not affect the progress of multicolor overprint printing.