How to effectively control the color tone of color bags

[China Packaging Network News] In the printing process of packaging bags, the color of the ink film of color printing bags depends mainly on the concentration and transfer rate of ink in the printing work. For some specific substrates or specific working inks, the concentration of working ink is relatively fixed, and the transfer rate depends on factors such as the viscosity of the ink, and also factors such as the printing speed. What needs to be noted here is that these elements will have different effects on the highlights, shadows, and midtones of prints when they change.

1, temperature and humidity changes

At room temperature, the liquid temperature of the ink is greatly changed, the flow state changes, and the color tone changes. This is because the change in temperature affects the viscosity of the ink. At the same time, dry meteorology with high temperature and low humidity will have a significant effect on the ink transfer rate in high light areas.

Therefore, when printing high-end products, the temperature and humidity of the printing shop must be controlled anyway. In addition, when the ink is used in winter, warm up in advance to reduce the temperature change of the ink itself.

2. Separation of synthetic colors

This phenomenon is likely to occur in light-colored and organic-color and inorganic pigments, such as the proportion of different colors. In particular, when the ink in the ink tray is too slow, precipitation will promote the separation of the synthesized colors. Therefore, it is necessary to pay attention to making the ink circulate smoothly.

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In addition, if the mixing is not sufficient during the color adjustment, the concentration of a certain color tends to increase as the printing progresses. Therefore, the machine should be thoroughly stirred using a machine such as a dissolver or other method before the printing.

3, ink deterioration and make the color worse

Because of the long-term printing, the ink solvent component is changed, or the ink in the air mixed with the ink causes the ink to deteriorate, rendering the color worse.

In order to prevent temperature drop due to heat of vaporization, a dry solvent can be used in combination. In high temperature and humidity, there may be a certain amount of moisture mixed with the ink, so in the event of abnormality should be added to the new ink, or all change, use more than the remaining ink because of a lot of dust mixed, it should be regularly filtered or repealed .

4, the ink viscosity and drying speed change

Changes in the viscosity of the ink can directly affect the color of the print. When the viscosity is high, the color concentration is relatively high, whereas when the viscosity is low, the color concentration is also relatively low. This influence sometimes becomes clear and must be highly focused. Due to the requirements of the printing process, the ink's working viscosity must be moderate. When the ink sticking is too large, it is not conducive to the transfer of ink, and it is easy to produce a paste scene. When the work of the ink sticks too little, the color of the printed product is prone to static electricity, and it is not conducive to the control of the ink.

The change in viscosity has a subtle effect on the flow area generated by the flow of the ink or the dot flow method, and is particularly significant in multi-color printing. Therefore, when the printing speed is affirmative, it is required that the viscosity of the ink be consistent from beginning to end, and it is better to use an automatic viscosity controller.

When the proportion of the solvent in the ink is changed, the drying speed of the working ink is changed, which in turn affects the ink transfer rate and the printing color. With regard to some inks with a small amount of ink, after a certain period of time is used in the ink tank, since the volatilization of the solvent naturally affects not only the working viscosity of the ink but also the ratio of the solvent and the volatilization rate, it is necessary to replenish the solvent in time.