Application of Transparent Ink in Printing and Troubleshooting 3v

If the misalignment of solvent misalignment control or process operation errors are very likely to cause many failures, so every link can not be sloppy.

Troubleshooting of common faults in clear ink printing

In the process of printing flexible packaging, transparent ink is mostly used with aluminum film or aluminum foil bottom to improve printing and visual effects. However, some quality phenomena often occur during the actual use process, such as the phenomenon that the clear ink has pitting and uneven inking after printing, which greatly reduces its expected effect. Therefore, it is necessary to be familiar with the nature and printing characteristics of the clear ink, and analyze and eliminate it.

1. Produce "pitting" phenomenon when printing transparent ink

The main reason and the solution to this failure is that after the printed product has been coated with an aluminum film, the flash effect will come out. However, if you look closely, you will find that the surface has a pinhole, as if it is not printed. The main reason for this failure is:

1 The surface of the embossing roller is not delicate enough, or there is foreign matter such as dust, which causes the ink to be thick enough here. Check that the embossing roller is dirty, wipe its surface clean, check the quality of the roller, and replace the qualified roller.

2 Plasticizers, lubricants, etc. contained in the film float to the surface to prevent the normal transfer and lubrication of the ink. Before printing, prepress the preheating of the plastic film, and if the film is not warmly printed, replace the appropriate plastic film.

3 The ink is too high in rheology, too dry, or lack of drilling agent causes ink transfer and poor wet adaptability. The ink titer should be reduced appropriately and slowly using thousands of solvents.

4 printing pressure is too small. The printing pressure can be appropriately increased and the printing pressure can be controlled (generally about 4 kg).

5 Problems of printing plate or embossing roller (expressed as regular pitting) The plate and embossing roller should be carefully inspected for defects. If any, re-plate or replace the roller.

2. Adhesion after printing transparent ink

The main reason and solution: In the high temperature, high humidity of the rainy season, the plastic film is prone to sticking during the reeling after the gravure printing, and the transparent ink is stuck in pieces, and the ink cannot even be separated from the underlying plastic film. Cause a lot of waste products. Most of the adhesions produced by printing products are caused by ink drilling, high ambient humidity, and high pressure, which are caused mainly by the following turbulences. 1 Insufficient heat resistance of the ink itself produces greater drillability under high temperature conditions. When the ink is dry, it cannot be seen with the naked eye. Since the printed product is rolled up, the residual solvent is difficult to evaporate. The resin in the ink cannot be dried and solidified to cause severe blocking of the finished product. Excessive residual solvent in the ink will cause severe blocking of the finished product after winding up. Too much residual solvent will not only affect its firmness, but also be extremely unfavorable to the food, causing odor in the package. 2 Because the ambient temperature is too high, the ink will be softened, resulting in adhesion of the print. At room temperature, many prints using clear ink are normal in handling and use, but when printed at high temperatures, the ink softens and causes blocking. Therefore, it is required that the operating temperature of the printed matter and its use should not exceed 50 degrees Celsius and it is better to control the temperature below 45 degrees Celsius. In addition, if the winding is too tight and the winding tension is too large, the adhesion solution may be caused by controlling the printing drying temperature and relaxing the tension. The winding should not be too tight. 3 ink and the substrate does not have a good bond, so that the ink on the substrate is not firmly bonded to the roll after the roll is easy to cause the transfer of adhesion. The solution is to choose the correct ink, control the quality of the ink to adapt to the substrate. In addition, the substrate surface can be treated to improve its affinity for the ink is also a method to reduce the occurrence of ink adhesion. It is generally necessary to ensure that the surface tension of BOPP should be 38 Dyne.

3. Printing transparent ink is not high gloss after aluminum composite

Main reasons and solutions: The main reasons for this phenomenon are: (1) The transparency of the ink itself should be replaced with a good transparency ink.

2 If the solvent volatilization during printing is too fast, the appropriate slow-drying solvent should be selected according to the requirements, so as to inspect and improve the ink rheology. 3 poor uniformity of the aluminized layer, resulting in poor anti-glaze to replace the aluminized film and ensure that the surface is uniform, no pinholes. 4 The squeegee angle is too large The plate hole is shallow. To adjust the angle of the squeegee, the angle is generally controlled at about 35 degrees.

4. Blocking phenomenon of transparent ink

Main reasons and solutions: This phenomenon usually occurs when the temperature is low. In this case, the ink should be heated at room temperature of 35°C. In order to prevent accidents, it must also be guarded by special personnel.

In short, the misalignment of solvents, improper control of the degree of boring, or misoperation of the process are all very likely to result in many failure phenomena. Therefore, every link cannot be sloppy. Therefore, in the use of transparent ink printing, in order to obtain the desired effect of all aspects must be strictly controlled, and according to the actual situation of printing choose the right ink.