UV offset printing and UV flexo printing

The main difference between UV offset and UV flexo is the ink, ink and plate technology. UV offset printing can take up to 16 ink rollers, dampening systems, and ink tanks due to the longer ink path, requiring a little more automatic control. UV flexo printing is simple because the ink path is simple and requires only a relatively simple manual adjustment.

On the other hand, especially those using digital imaging plates require high-quality printing, which significantly increases the production cost of UV flexo printing. UV offset printing and UV flexo printing have their own advantages and disadvantages in particular printing requirements. There is no absolute "winner", only the most appropriate processes to adapt to different needs.
In the printing area, UV flexo printing has more unique advantages. It can be glazing, printing metal colors, can transfer 1 to 12 micron ink layer, and can almost simulate the tactile effect of screen printing. At the same time, it can handle very fine gradient colors and printing processes. The UV offset ink transfer is limited to about 2 microns, so its high quality printing advantages cannot be extended to all printing processes.

However, due to the short ink path, UV flexo printing can be converted faster than UV offset printing. Modern UV offset printing units can also automatically clean multiple groups of printing units, significantly reducing conversion time.

UV flexo printing can provide better self-visibility than UV offset printing, especially in bright colors and strong contrast colors (contrast colors).

UV offset printing still retains its solid advantages, not only in the gap in print quality, but also in a simpler, more efficient way to meet quality requirements. If there are high-quality requirements for processing, platemaking sources are more likely to meet requirements, and printing variables are more standardized. UV offset printing can be easier and more cost-effective to achieve high quality printing requirements.

The modern UV offset EPN unit XpanndTM offers a fast switching printing combination with low-speed, fast-response modern presses such as Athena, l-Combat and Xpanned, with computer intelligence technology in a global or regional standardization environment, making UV offset and UV flexo also perform equally well in repetitive processing because most of the variables are already controlled by the computer. In some simpler configurations, UV flexo has a clear advantage.

The limitations of UV offset printing are not flexible enough in repeat length dimensions because of the high value and size of the printing press. Although label printers have shown from practical experience that rotary machines can use 4 to 5 sets of repeat lengths, it is sufficient to cover most of the current needs. UV flexo printing can print any repetitive length size, and the investment cost is very small.

Wet offset printing is the most common printing process in the printing industry today. The basic principle is to use the ink balance between the printing area (printing ink) and the non-printing area (water) on the printing plate. The key is to maintain stability and control of the ink balance. Waterless offset printing uses a silicon coating on the printing plate to remove the ink for the non-printing area and balance control. It also eliminates the use of water as a medium. Water is not used for printing, making waterless offset print dots sharper and better visible. Waterless offsets have the potential to reach higher line counts and contrasts. Wet offset printing is more compatible than waterless offset printing. Water can be considered as a cleaning plate, ink path, a bit like the self-cleaning function in printing. In the water-free printing plate, dust, paper dust will damage the water-free offset printing silicon coating, making the selection of substrates and working environment cleaner requirements more stringent.

In general, waterless offset printing requires higher printer maintenance and operator skills. It is the slight mistakes in the process, and the quality of the printing may also vary greatly.

The problem of ink temperature has been the development of technology for many years. Waterless offset printing is still a very complicated process, and every process requires perfect control to achieve high print quality.

At printing speeds higher than 150 meters per minute, wet offset printing requires cooling rollers, cooling the heat accumulated in the printing unit, which may affect the performance of the ink and the density of the ink.

Waterless offset printing requires cooling rollers and cooling ink at any print speed, as well as cooling the plate at the center of the platen roll. Because the ink temperature is extremely sensitive to control the print quality. The working temperature of the ink is limited to a very narrow range, only 3-4°C. Above or below this temperature, the ink becomes unstable and the print quality is affected. In order to achieve better control of the printing effect, the plant needs air conditioning temperature control.

Offset is the most demanding printing process for mechanical components. When flexo printing only requires a limited printing pressure, offset printing requires a lot of pressure to be applied to the platen roller to transfer the ink. The difference in workmanship, assembly, and firmness of the offset printing press, as well as the design of the ink path and the ink management system, will affect the final print quality.

Most commercially available offset heads can achieve acceptable print quality at speeds of 30 to 40 meters per minute. To exceed the speed of 50 meters per minute in order to get continuous good quality prints. The Xpannd offset printhead produces continuous high-quality printing at a printing speed of 12 meters per minute. The amount of waste in the print setting is very small, and it is very close to the flexo process.

With the calculator interface to control all parameters of the ink path, but also from the main control surface through the automatic servo remote control ink management system can be used to store the ink parameters and repeatedly call for use in repeated processing, or as a new processing Set the basis. In the settings, waste and time can be greatly saved, and all ink parameters are controlled and can be copied!

Source: China Printing Materials Network