UV offset printing is a global standard (II)

Printing range

In terms of printing range, UV flexo printing has significant advantages over UV offset printing. It can be glazed, printed in metallic colors, and can transfer ink layers of 1 to 12 microns, which can mimic the tactile impression of screen printing. At the same time, it can print extremely fine gradient colors. UV offset ink transfer is limited to about 2 microns, so its high quality printing advantages cannot be extended to all print jobs.

Ink conversion

Due to the relatively short ink path, UV flexo printing can be converted faster than UV offset printing, and modern UV offset printing units such as XpanndTM can perform automatic cleaning of multiple sets of printing units, significantly reducing replacement time.

Self-disclosure

Compared to UV offset printing, UV flexo printing provides better self-display, especially in bright colors, strong ground colors, and strong contrast colors (contrast colors). In high light areas, UV offset printing has certain advantages because the smooth printing effect of UV offset printing is recognized by customers.

Printing process

Compared with UV flexo printing, the strong advantage of UV offset printing is not the difference in print quality, but that it is easier and more economical to meet quality requirements. For those quality-requiring jobs, offset platemaking sources are easier to find and printing variables are more standardized.

standardization

UV offset printing has long been entrenched in global standards, and UV flexo printing mostly relies on local standards. Both printing methods can get similar print results, but UV offset printing has a wider range of applications and lower costs.

Short print: new job

The modern UV offset printing group can provide fast conversion printing combination, adjust at low speed, and quickly adjust the ink function according to the substrate, so that UV offset and UV flexo are almost the same in terms of the loss of the substrate and time in converting the new job. . Although UV flexo has the advantage of shorter ink path, UV offset provides more flexibility for ink management. If the UV flexo process has been standardized locally, the two are similar. Otherwise, UV offset printing can have a clear advantage because its standards are global and its final printing results are also predictable on a global scale.

Flexo printing is advantageous when printing inks frequently change color, and when printing on unknown substrates, because UV offset groups need to coordinate the ink balance and UV flexo printing can start in real time. UV offset printing has advantages in handling unspecified spot color printing because it has achieved the most advanced standardization in the supply chain.

Short-run printing: duplicate jobs

Modern printing presses such as AthenaTM, I-CombatTM, and XpanndTM, which have computer intelligence in a global or regionally standardized environment, make UV offset and UV flexo the same in repeat jobs because most variables are already Handed over to the computer.

In some simpler configurations, UV flexo has a clear advantage because of its short ink path and the stability of the anilox roll ink supply.

limitation

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

UV flexo printing is limited to printing on rough surfaces such as wine labels or recycled cardboard because it uses direct printing technology. UV offset printing can be printed on any substrate without increasing production costs.

Why Use Wet Offset, Waterless Offset

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 as a non-printing area to remove water and ink balance control and also eliminate the use of water as a medium.

Printing quality

No water is used to print sharper and better print dots for waterless offset printing. Waterless offsets have the ability to achieve higher line counts and contrasts.

Print persistence

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 at the time of printing.

In water-free printing plates, dust and paper dust can damage the water-free offset printing silicon coating, making the cleaning requirements for choosing substrates and work environment more stringent.

In general, waterless offset printing requires higher printer maintenance and operator skills. It's the slightest mistake in the process, and the quality of the print may change a lot. The problem of ink temperature, despite years of technical development, waterless offset printing is still a very complicated process. Every process requires perfect control to achieve high print quality.

Claim

At printing speeds higher than 150 meters per minute, wet offset printing requires a chill roll to cool the heat accumulated in the print block, which can affect ink performance and ink density.

Waterless offset printing requires cooling roller cooling at any print speed and cooling of the plate at the center of the plate because the ink temperature is extremely sensitive to controlling print quality. The working temperature of ink is limited to a very narrow range, only 3 ~ 4 °C. Depending on the supplier, 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 air conditioning temperature control is required inside the factory.

Consumables

There is only one supplier of waterless offset printing plates, and there are not many ink suppliers. Suppliers of wet offset materials are in fact numerous.

Consumables cost

Since waterless offset printing is not available in the industry, the cost of consumables is significantly higher than wet offset printing. In some cases, inks and plates can be up to 3 times more expensive.

Disposal at the time of adjustment

Waterless offset printing claims to reduce machine waste because it does not require treatment of ink and water balance. On the other hand, modern wet offset printing can be fully automated for ink and water treatment. It also makes water ink balance control more accurate and responsive, and is comparable to waterless offset printing. In fact, the process of controlling the ink will largely influence the performance of wet offset printing and waterless offset printing.

Printing on plastic substrates

Since there is no water, waterless offset printing can achieve good printing results in a short printing turnaround time, provided that conditions such as temperature and cleaning must be met, and the basic parameters have been set correctly.

For substrates that they do not understand, wet offset printing still takes more time, resulting in more waste products. When repeating the same printing job on a known substrate, the advanced offset printing unit can store the existing ink parameters, can repeat printing, and its preparation time is shorter, similar to waterless offset printing.