The development of flexo technology (below)

The development of drying technology makes the ink film cure faster, which makes the printing effect of flexo gold ink and silver ink even surpass the offset printing. In recent years, the ink pigments can be made finer, so that an anilox roller with a higher number of lines can be used, so that the flexo printing process can also reproduce finer images.

Photosensitive resin plate digital imaging or direct engraving

Since Drupa 1995 first exhibited a digital imaging flexo and Drupa 2000 exhibited a direct-engraved polymer flexo, a fierce controversy has continued: Which technology is superior in quality and economy? What? Direct engraving plate making technology is the use of laser engraving on the surface of the flexible plate material, using this method to engrave the rubber plate has been more than 30 years of history. The flexo direct platemaking technique uses a photosensitive resin flexographic plate with a black mask (LAMS) on the surface to expose it on a flexo CTP platesetter, remove the LAMS layer of the plate graphic portion, and then perform UV exposure, rinse and dry.

In recent years, the quality of photosensitive resin flexo plates has been increasing, which not only has higher resolution but also has a shorter imaging time. The flexo CTP system uses eight Nd:YAG lasers to expose the flexographic plate, but after the exposure, the plate needs to be exposed and imaged by UV. Newer platemaking technologies, such as the Cyrel FAST system, use special techniques to remove excess parts of the plate with high heat energy and use it immediately without having to rinse it. However, the CyrelFAST system currently has limitations on the format size of the printing plate, but it is expected that it will not solve the plate-making problem of the large-format flexo plate.

Advantages of direct engraving flexography

Although low-resolution direct-engraved rubber plates have become commonplace on the market, the direct plate-making system directly on BASF's polymer plates exhibited at Drupa 2000 has attracted attention. However, it was criticized that the cO2 laser beam used in this system was too large to reach high resolution and was not economical, but this problem has now been completely resolved. Because BASF and STK Schablonentechnik recently announced that the first such direct engraving system was installed at GRS in Germany, the diameter of the light spot can be made very small by overlapping laser spots.

In addition, the manufacturers of direct engraving systems have also improved the system. The laser beam is changed from one beam to three beams. Since the laser energy can be changed, the evaporated material can also reach different depths, thus making the dots more clear. This is because CO2 laser and Nd:YAG laser are used. The CO2 laser first forms a roughly embossed effect (mainly embossed depth), while the Nd:YAG laser can form different dots because the spot diameter is smaller. However, because the Nd:YAG laser cannot be absorbed by all materials, it is limited in use.

In the seminar of the German Flexographic Society in 2001, different platemaking methods were compared. In 2003, the seminar discussed the advantages of direct engraving flexo plate making. It is generally believed that the quality of flexographic direct engraving plates appears. In the field of traditional analog platemaking, not only the QualiyD0t technology developed by the German company Theimer and Hex0Technik Handels and InnoFlex has emerged, resulting in greater contrast after imaging, and the development of the software has also enhanced the simulation of flexographic and digital platemaking. The competitiveness.

Thin sleeve technology

Another technology that promotes the improvement of flexo printing quality is the introduction and application of thin sleeve flexo. The thin-sleeve technology combines the advantages of a single sheet of photopolymer flexo and a non-deformable circular sleeve version. The photosensitive resin is first flexibly mounted on a thin sleeve, and then imaged and rinsed, without having to be as flexible as a single sheet. The image is finished and mounted on a circular plate roller to avoid image distortion. The price of this system is high, so the application is not yet universal.

Development continues

The development of flexographic technology continues, whether it is a flexographic printing machine or an anilox roller, whether it is ink or plate material, as well as register control, closed scraper device, the development of these technologies will promote the overall level of flexographic technology .