How to Use Roller to Improve Flexo Printing Quality

Roller and ink

Our goal is to achieve the ideal printing quality with the thinnest ink layer. This looks simple, but it is the essence of flexo printing to achieve superior printing. Roller from the earliest chrome roll development to the current 60-degree angle laser engraving ceramic roll, is also a step toward this goal.

The capacity of the roller has a direct relationship with the thickness of the ink layer. The capacity of the roller is the ability of the fingerprint roller to hold the measurement. The size of each cell on the roller determines the capacity of the roller, and the capacity of the roller determines the thickness of the ink layer. The number of lines of the roller has a direct relationship with the capacity. Therefore, the higher the number of lines of the roller, the greater the number of cells in the unit length, the smaller each cell, the smaller the capacity of the roller, and the thinner the thickness of the ink layer.

As shown in FIG. 7, the 440 line roller provides a thinner ink layer than the 330 line.

We print with a thinner ink layer, which has the following advantages:

※ Thin ink helps to control the dot expansion, thus achieving a wide range of gradation ※ make the color reproduction more realistic, stronger contrast ※ thin ink can achieve accurate color registration, ensure high-speed printing ※ The total area of ​​printing unit ink Larger, thus ink ※ Thin ink layer can make four-color printing overlay more uniform, achieve better color saturation and reduction

How does the thin ink layer achieve the above advantages? The following items are analyzed:

Let's look at the relationship between the thin ink layer and ink cost. We use a thin layer of ink for printing and must use high concentrations of ink. Everyone knows that high-concentration inks are more expensive than normal inks. Will this increase ink costs? The answer is no. Because a thin layer of ink can make a larger area per unit of ink, thereby reducing the total amount of ink used, this allows you to print higher quality prints at the same or even lower ink cost. Therefore, a good roller can realize a thin ink layer, and at the same cost, high-grade prints can be printed.

Second, we look at the relationship between the ink layer and the range of gradation. Let us first look at Figure 8.

The figure shows the transfer of the ink. The ink in the figure expands and expands on the printed material under the printing pressure to form dots on the printed product. If the thickness of the ink layer is large, dots formed by transferring to the object to be printed are large, and dot dot enlargement rate <DOT GAIN> is large. For a better understanding, let's look at this example (Figure 9).

(to be continued)