The company Hell Gravure Systems has further developed the flexographic printing with precise laser engraving of elastomer molds under the name Premium Flexo. Squashed edges and cloudy expressions with which they brought flexo earlier in connection therewith belong to the past.
Further processing possibilities when flexo range of folding cartons, displays, carrying constructs, bags and sacks up into cups together cover sheet and labels and shrink or stretch films. (Photo: Hell Gravure Systems)
The flexo is a direct high-pressure process. That is, the printing elements are as sublime in a stamp and transfer the ink directly onto the print substrate or packaging material. The printing plate materials are flexible polymers or elastomers (rubber). The variety of printable materials is nearly inexhaustible: plastic films with different functional properties on metallized surfaces to paper, cardboard and corrugated board. The finishing options are no less diverse and range of folding cartons, displays, carrying constructs, bags, sacks, cups together cover sheet and labels to shrink beziehungseweise stretch films. Other strengths of flexography are a cost-effective platemaking compared to other printing processes, more variable web widths and especially adaptable to the packaging material printing ink systems based on water, solvents or UV-sensitized components.
Also in the Dry offset printing plates are used, to those in flexographic printing are quite similar. However, the Dry Offset is an indirect letterpress printing. It got its name from the traditional offset printing, because, like this transfers the print image on a blanket on the printing material. But in contrast to the normal offset printing, in which the colors one by one put on paper, the dry offset gathers all colors first on the blanket in order to subsequently transfer the entire design with all the colors in plastic tubes, mugs and containers or aluminum cans.
New possibilities of flexographic printing
The first so-called Premium Setter installed Hell 2006 at the market. Meanwhile, high-power fiber laser engraved directly into elastomeric printing plates and sleeves. A maintenance-free optical head and a variable spot size make the technological highlights of the premium flexo technology. The technology can reproduce high-quality raster images and rasterized waveforms. Positive and negative fonts and line elements are very fine. In addition, a high color density, brilliant photos and high-contrast images can be obtained.
The Premium Setter S1700 is available with a one- or two-beam laser option. The disc formats be 1,650 x 1,170 mm at a thickness of 3 mm. Until 1.700 mm ball width a peripheral 320-1220 mm is possible. At 1,500 mm ball width a peripheral 250-1220 mm. (Photo: Hell Gravure Systems)
The flexographic printing opens up so increasing the premium segment. Branded companies increasingly recognize that the flexographic printing can deliver premium quality packaging types today which previously had to be produced with average quality. Especially in the food segment offers the flexo benefits through grease repellent, frost-resistant and air-permeable film properties. Also at the corrugated box production directly engraved elastomer plate offers new opportunities – both in post-print (Direct print) and in the preprint (forms of Kaschierdecke). Previously served directly printed corrugated board packaging as transport larger goods and consequently was only printed in one color with font and icons. Today fine corrugated cardboards one hand and engraved printing forms on the other hand the conditions that corrugated cardboard can be printed with multi-color images and graphics. High quality has reached a fortiori in Preprint:. The flexographic printing forms on the Kaschierdecke with engraved elastomer forms are indistinguishable without a magnifying glass of offset or gravure printing
Now the premium flexo technology also enables the Print functionally reliable stroke and QR codes and how to implement hidden features in the grid: Hidden Images. Because with penetration in the premium segment to grow, the demands on the forgery-proof packaging.
In addition to classic flexo printing on packaging materials are Premium Flexo proves even in other applications to be advantageous. For the elastomers can be not only in accordance with the ink type optimize, but also in their Shore hardness or in its elastic pressure mold assembly to a robust dimensionally stable metal back. This can elastomer properties such as swelling resistance, high mechanical durability and quality requirements for specific tasks and materials are combined.
Of this also benefits the folding carton on sheetfed offset presses. Complicated paint subjects be realized for years of repro houses on photopolymer coating formes, but how in the flexo varnishing be increasingly replaced by laser engraved elastomer sheeting. With correspondingly hard elastomers can be produced even embossing forms.
Dry offset remain curves and lights up in extremely low tonal printable. This expands the potential of direct printing to achieve the desired appearance on the shelf. More sophisticated designs with more curves can be realized.
laser engraving in the third dimension
was available until the modern direct engraving in elastomer, there was in flexography no serious alternatives to decades proven photopolymer plate. The polymer is enriched with a so-called photoinitiator, which reacts to UV radiation and causes a hardening reaction in the exposed areas. This results in the printing elements. By contrast, the covered areas remain chemically inactive, form of no fixed structure and are washed in further process steps as uncured polymer residues. They form the non-printing grooves in the high pressure mold. In this way can be combined with two-dimensional masks a three-dimensional relief plate produce. The UV exposure of later printing areas is selective by design mask. This was in the conventional photopolymer plates and sleeves, a negative film, which served as a template. With the introduction of the digital workflow of the film has been replaced by a thin black mask layer. Black absorbs heat, which produces an infrared laser on the LAMS layer (Laser Ablation Mask System) whereby the printing areas exposed and made accessible to the UV rays.
Nevertheless, these digital imaging is just one method using a printing technology targeted, customized profile influencing the edges of a halftone dot does not allow, as in the analog imaging. The secret of the quantum leap of precise direct engraving of elastomer is therefore defined in the control of the fine laser beams. This occurs not only in the surface but also in the depth, ie, the third dimension of the raster point. In combination with the robust and versatile elastomer the printer can thereby achieve printing results that remain stable throughout the run
One disadvantage of photopolymer forms that this manufacturing principle requires many process steps:. Laser exposure, multiple UV exposure , washing and drying. By UV radiation injurious to health, ozone is produced in atmospheric oxygen, which must be sucked consuming. The Auswaschstrecke not only takes up space, the washing solution also contains chemicals and caused difficult depositable and especially to dispose waste. On the other hand provides the direct engraving with Premium Flexo a two-stage process, which saves over the six-photopolymer process space, time and costs. The elastomer comes as ready-chemically cured material in the platemaking process, which the user saves the entire cost of Reliefhärtung and -auswaschung. In short, the printing form is ready and available more quickly
There are also advantages in the pressure.. The user can rely on a higher stability of the elastomeric printing forms. By three-dimensionally defined Relief – Undercut, First Step, Cross shape and relief depth – and the digitally controlled laser intensity of high-energy laser beam ultrafine may draw up the relief shape to the full depth in one step. Detached and negative halftone dots with small relief depths are no longer a problem. In addition, the resolution of 2540 dpi can be increased to up to 5,080 dpi – with no impact on the engraving time. This detailed and filigree motifs, finely rasterized images and patterns and brilliant colors and high contrasts or Tonwertumfänge can be realized in the pressure.
For her critical
Premium Flexo technology
- Job Ticket workflow: Engraved Start at your fingertips
- PremiumProfiler: design of the three-dimensional shape of halftone dots
- Online Engine : On-the-fly calculation of 8-bit TIFF engraving data
- Premium Setter: engraving systems for various formats and with a variable number Graviermodule
- elastomer printing form: plates and sleeves of different Manufacturer
Company
Hell Gravure Systems GmbH & amp; Co. KG
Philipp-Reis-Weg 5 24148 Kiel
Germany
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