For card production UV ink printing, after understanding the necessary configurations of the inkjet printing machine, let's take a look at the requirements for the printing materials.
1. UV Ink
UV ink is a light-curing absorbent ink. Since many cards need a laminated layering process, the performance of the ink itself is particularly important. There are two key points: First, it must be resistant to high temperatures and high pressures, and not change color or fade under the high temperature and high pressure conditions of the laminating machine; second, the adhesion between it and the plastic film must be strong, with a minimum force of 6N. In addition, the selection of UV ink for card production is also crucial. Apart from ensuring the quality indicators of the ink itself, it is also necessary to match the UV lamp wavelength of the printing machine. Since many manufacturers use color inkjet drafts as the original material for printing, it is recommended to choose scale and color yellow, magenta, cyan inks. Moreover, when mixing spot colors, it is advisable to select inks with low viscosity and good activity. The European Ak ink is better.
2. Special Printing Plates
UV inkjet printing requires special printing plates that are wear-resistant and durable. They do not need to be protected with a protective film during mid-process stops, and old plates can be reused. They are particularly suitable for the transfer of UV ink. During exposure, the dot reproduction rate is high, and basically, 2% of the dots do not lose their quality, and 98% of the dots can be distinguished. Currently, the quality of Fujitsu UV plates in Japan is good. Considering the printing cost, for short-run, small-scale jobs, the text plate can be appropriately used as an ordinary plate, but the plate film is prone to wear, so extra attention should be paid during printing.
3. Rubber Sheets and Liners
To ensure the best transfer performance and dot reproduction of UV ink, it is best to use air cushion rubber sheets. Because they have good acid resistance, oil resistance, hydrophobicity, and excellent ink transfer performance, they can ensure that the dot deformation is minimized during the printing process, the printed graphics are clear, the reproduction of the highlights is good, and the wear of the printing plate is small.
The rubber cylinder liner should use a neutral and slightly hard material. Due to the rough surface of PVC and other sheet materials, it can lead to a high increase in the enlargement rate of the printing dots. Using a neutral and slightly hard liner can make the dots clear, smooth, with good reproduction, small changes in the geometric shape of the graphics, and a small increment in the width of the graphics and the printing sheets.
4. PVC and Other Sheet Materials
PVC and other sheet materials have a glossy and matte surface. The glossy surface is smoother, while the matte surface is rougher. Choosing the printing surface is very important. It can avoid many printing quality problems. Usually, the matte surface of PVC and other sheet materials is used as the printing surface to ensure that the ink does not pull the fibers when printing on the smooth surface, the ink has strong adhesion between the material and the ink, the ink is rich and does not show white spots. In addition, the printing pressure should be appropriately increased by 0.02 to 0.05 mm compared to the standard pressure.
5. Auxiliary materials
The cleaning water for UV printing, the cleaning agent for rubber blankets, and the cleaning solution for printing plates all need to use dedicated products. This is particularly important for the lifespan and performance of UV ink rollers, UV rubber blankets, and UV printing plates. Although the cost may be higher, it can be flexibly applied according to the actual situation. Ensure to clean the ink rollers once a week; when the machine is stopped, use the dedicated restorative agent to clean the rubber blankets. This can not only ensure the effective elasticity of the rubber blankets but also ensure the balanced and consistent color when the machine is restarted and avoid color differences.
