Print high-quality barcodes, choose ink color and performance

Print high-quality barcodes, choose ink color and performance

The color difference caused by the color matching of the ink, the thickness and concentration of the ink layer, the spreadability of the ink, the amount of ink supply and the printing pressure will all affect the scanner's reading of the barcode. To print high-quality barcodes, be sure to pay attention to the choice of ink color and performance.

1. When matching the color of the ink, the color cast of the ink should be considered

The color shift of the ink also has a great influence on the accuracy of the barcode. Theoretically speaking, as long as the ink is used according to the color ratio in Table 1, the bar code requirements can be met, but because the printing ink has the defect of impure hue, the phenomenon of color cast will occur. For example, due to the wrong absorption of red light by blue ink, the reflectivity under red light will increase, which reduces the PCS value of the barcode.

Therefore, the color of the ink should be strictly controlled, so that the ink density is uniform, the hue is saturated, and the purity is high. It is best to measure whether the reflectivity of a certain ink under red light meets the requirements before printing the magnetic barcode. Metallic inks (such as gold) cannot be used to print barcodes because their reflectivity and gloss will cause a specular reflection effect that affects scanner reading.

Table 1: Barcode Color Matching

2. Barcode printing requirements for ink concentration and ink layer thickness

Since barcode printing is solid printing, the reflection density D that can be achieved by printing is related to the optical properties of the ink and the thickness of the ink layer. During the printing process, the reflection density of the printed product increases with the increase of the ink thickness, but when the ink thickness reaches a certain value, the density reaches saturation.

According to different printing processes, the thickness of the ink layer on the printed matter is different, offset printing is 2-4 μm, embossing is 8 μm, flexo printing is 10 μm, gravure printing is 12 μm, and silk printing can reach 30 μm. According to the test, it can be calculated that the solid reflection density of the printed products obtained by the above printing types can reach more than 0.3. In addition, black, cyan, blue, green and other colors are fully absorbed by red light, so the above-mentioned printing processes are used to print barcode strips. rate can meet the requirements.

3. Requirements for ink spreadability

The ink viscosity directly affects the fluidity and spreadability of the ink. In barcode printing, the ink viscosity is low, the ink spreads large, and the bars are easy to become thick. Therefore, the viscosity of the ink for barcode printing should not be too large.

4. Ink supply

If the ink supply is too large, the substrate cannot be absorbed quickly and completely, and it will spread on the surface of the substrate, resulting in a decrease in accuracy.

5. Printing pressure

On the one hand, if the pressure is too large, the shear stress of the ink will increase, and the fluidity will increase, causing the ink to spread; will widen.

Therefore, it is necessary to adjust the printing pressure, printing speed and other factors to an appropriate degree according to different printing methods, the rheology of different inks and the ink absorption performance of the printing materials.

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