20.04.2010

Flexography in package printing growing

During the past 30 years, flexography has been demonstrated to be a printing technology with a very impressive growth in terms of quality and productivity. It passed from low to high quality printing and today is widely used for packaging production, in different applications: flexible packaging, label and tags, plastic bags, carton board and corrugated, shrink-wrap, etc. Flexography becomes the standard and today is the main printing technology used in the packaging printing industry in America as well as in Europe (Central, Western and Eastern). But the technology is not standing still and there are continuous process improvements and innovations that strengthen flexo´s leading packaging printing position. A wide range of industry vendors are taking successful steps to make flexo even more productive, cost effective, sustainable and printing higher consistent quality. Improvements are seen along the whole production process, from the packaging design to the final product. Improvements in the plate – making room In order for the quality of flexo printing to rival other technologies, specially offset, the flexo platemakers (services and printers), can use solutions able to combine high-resolution optics with an exceptional screening output. Devices capable of combining 4000 dpi HD optics with unique screening technologies deliver the advantage of sharper and more accurate imaging. This combination makes it possible to achieve outstanding print quality with a straightforward plate production process. Just as significant, this technology is very easy to use and there is no longer any need for tweaking or adjustments. Moreover, the rounder dot shape produced thanks to this technology combination, means that they are more stable on press, resulting in longer print runs with the same printing plate - even more than standard digital flexo plates. With longer print runs, the press stops less often for wash-ups, resulting in greater productivity. HD Flexo brings also significant sustainability benefits as well, as it avoids any manual lamination of the plate. Therefore there is no film to dispose once the plates have been imaged. Moreover, thanks to the use of thermal technology for the processing of the plates, theres’ no need to use solvents, potentially damaging to the environment. Printers who work with plates generated from HD Flexo typically reduce make-ready sheets required to get to acceptable color by 66%—resulting in much less waste. “HD Flexo is a big step in flexo printing,” comments Jef Stoffels, Marketing Manager at Esko Artwork and Voice Speaker for flexo4all. “It makes life easier for brand owners, print buyers, trade shops and converters. It does not require a significant capital equipment investment as it is just an upgrade of existing and running equipment. Trade shops or converters will benefit from HD Flexo because, with a safe, high quality process, they can compete with offset or other printing techniques without losing quality or having to adapt prepress specifically for the process.” Improvements in the press room Even the printing process in undergoing to improvements, thanks to increased levels of quality controls available from some press manufacturers. In the world of flexo, the time taken in setting and adjusting a production run is a key factor when it comes to evaluating productivity. On top of this, returned orders affect the reputation of a company and increase its costs. With these issues in mind, new high performance, quality control systems make possible to guarantee that 100% of the production from a flexo printer meets the quality standards set by the customer, while simultaneously cutting setting times and reducing waste. Thanks to the high level technology employed with these quality control systems, a wide range of print defects down to just 3mm2 in size can be detected. When used in carton board application, the sheets containing elements identified as defective are automatically ejected, highlighted, or ignored by the press, according to the settings defined for the detection zone the defects occur in and the level of quality chosen by the operator. Philippe Kunz, Marketing & Communication Project Manager at BOBST, another flexo4all core member, comments: “iQ300, the quality control system developed by BOBST, is the essential final filter, verifies the production and ensures that the printing reaches the quality needs of even the most demanding end-users”. Where flexo beats offset The cardboard packaging market is undergoing a period of renewed development. This is true in Industrial countries, where the standard of living is high, as well as in developing countries, including large Asian countries such as China and India. As a consequence, within the printing and converting industry investment in innovative technology is going to grow. New alternative solutions to offset printing appear, offering streamlined production processes, excellent qualitative results and interesting profit outlooks. Flexo printing technology results particularly convenient when low volumes of production are required, often within a limited budget of expense. An example is the pharmaceutical industry, whose large orders include such a range of variations that each project is regarded as a separate order. In these kind of packaging applications, flexo printing provides a higher level of chromatic balance and colour constancy than the average offset. “The best results are obtained by flexo printing with UV ink”. – states Paolo Grasso, Area Manager at OMET, again a flexo4all core member. “Without denying the excellent printing quality of sheet-fed offset printing used for luxury packaging, many packaging processes can be transferred to flexo lines with significant monetary and time savings. This concept is breaking into many paper product companies as it provides immediate benefits to those who opt these solutions”. Flexo benefits on inking edge The latest developments of polyurethane (PUR) resins have opened up new applications. The successful increase of flexography printing of e.g. laminates is highly correlated to the almost unlimited possibilities of the PUR synthesis. Modern polyurethane resins are synthesized through the complex combination of various intermediates by multi-step reactions. Thus high-molecular, film-forming resins are formed exhibiting excellent adhesion properties, high solubility in alcohol, lowest solvent retention, high blocking and sterilization resistance. Properties of polyurethane resins can be varied in multiple ways by selecting specific intermediates. Tailor-made PUR resins can be manufactured and their characteristics can be adjusted exactly to the respective requirements.


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