Anilox Impact

Today's Anilox Roller Can Provide a Bright Future for Packaging

April 2011 By Paul Teachout, Harper Corp.

multipage

Today’s anilox roller technology has grown to be much more than a transfer roller for colorants. It is a versatile tool in many decorative and coating applications. Anilox rollers are now being used to create high opacity whites and base coats for flexible packaging, tactile coatings for raised-imaged varnishes, as well as applying coatings and adhesives for cold foil and multiple other decorative applications.

All these opportunities have allowed today’s anilox roller technology to compete with and share in the market with other processes that are much more costly. Even the advancements of high definition flexographic digital plates are incorporating this tool to create graphics that were once thought of as unobtainable.

Having the ability to take advantage of all these processes on a flexographic printing press has allowed converters to offer many cost-effective solutions to their customers. We no longer require expensive rotary screen and hot foil units to compete in today’s competitive markets. It is very common now to see packaging that is printed 300 LPI with opaque white, tactile varnish, and cold foil accents—all on one package, all flexo, and all printed in-line with no added investment in ancillary equipment. This is all being done, in part, with special care in anilox roller selection and use.

High definition flexography

The latest in digital plate technologies is taking great advantage of today’s anilox roller. As plate screens continue to climb, it is up to the anilox supplier to deliver an engraved roller that supports the plate structure and graphic design. It is critical for the plate and anilox roller to work together to maintain the crisp highlights and mid-tones that are required from today’s CPGs and converters. Current screen rulings are approaching 300 LPI and beyond.

This requires that the dot structure be uniformly supported by anilox cell structure to reduce over inking, bridging, and other print-related defects. The tried-and-true 60 degree hexagonal engraving is still proving best for this task. Nothing to date beats the honeycomb pattern for strength, rigidity, wear characteristics, and all-around dot support.

Having as many cells as possible under the highlight dots is what will lead to clean and crisp reproduction. To properly support the graphics, a rule of thumb for the required anilox cells per inch (CPI) is five to six times the plate screen. This means that a 300 LPI image will require a 1,500 to 1,800 CPI engraving to properly support the graphic reproduction of a one percent dot.

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