Experiences on Label Printing Supplies and Environmental Options

Paper

The label pattern is mainly on the ground, which requires the smoothness, whiteness and glossiness of the paper. If you want to get a satisfactory label printing effect in the field, the smoothness of the paper must be high to ensure that the printed product has a uniform density value, so that the surface of the printed product does not cause a flower. Because the paper with high glossiness and whiteness can enhance the contrast between the ink and the paper, and make the picture more clear, the flexographic ink shows a more vivid effect. Therefore, when choosing the flexo label paper, The two indicators of gloss and whiteness are particularly important. The whiteness and gloss of the paper should be selected under the condition that the paper opacity is consistent. The whiteness should be higher than 85% and the glossiness should be higher than 55%. The tensile strength of paper is another important selection indicator. Only with good tensile strength can we ensure that the paper remains stable throughout the printing process, and that the label maintains good overprint accuracy. The surface strength of the paper is also an important indicator. Only the paper with a good surface strength can make the field printing fuller. Do not appear printed on the surface of flowers, uneven color phenomenon.

2. Ink

If the proportion of pigment is too high (more than 35%), the viscosity of the ink will increase and the thixotropy will increase, affecting the transfer of the ink. At this time, the ink must be stirred as necessary and the ink should be placed at a suitable temperature ( Store at 20°C). When selecting the ink, the particle size of the ink and the drying performance of the ink should also be considered. In particular, when there are large areas of color on the label, and there are text, lines or halftone images, it is necessary to consider different patterns of ink drying speed requirements are different, too coarse pigment will produce some wear and tear on the anilox, in the choice Also pay attention to the ink.

3. Printing environment

Environmental factors are important when printing flexo labels. The drying speed of printing ink, lines and other parts will be accelerated due to the volatilization of ammonia and amines. It is necessary to improve the micro-environment of the ink. Humidifying device is installed in the ink tank to suppress the volatilization of such substances and control drying. speed. In addition to controlling the micro-environment, the control of the overall environment during the printing process is also very important. When printing different types of paper, patterns (mainly on the ground, or line-based) labels, the choice of humidity is not the same. General waterproof paper printing requires higher humidity, and large areas require less humidity in the field. High ambient temperature will affect the drying effect of inks (water-based inks, solvent-based inks), resulting in paste printing and other phenomena; if the temperature is too low, the viscosity of the ink will increase, thus the temperature and humidity of the printing environment will be stable within a certain range. It is necessary inside. In China, the four seasons in the north have obvious changes and the temperature and humidity are quite different. It is best to seal the printing environment, install humidifiers, air-conditioning and other equipment to create an environment suitable for flexo printing; in the south, due to the occurrence of rainy weather, the workshop Dehumidification should be used as a focal point for creating a flexo environment. The range of temperature and humidity suitable for flexo printing is generally as follows: the temperature is about 25°C, and the humidity is 50% to 60%.

4. The operator

In label flexo printing, human factors are also critical. Operators should mainly have the following qualities: a high sense of responsibility; a certain understanding of mechanical principles and electrical knowledge; a certain basis of chemical knowledge; mastering various printing processes; to sum up. Only by summarizing and refining the problems that arise in printing can we continuously improve our capabilities.

Source: "Printing Technology"