As competition for shelf space heats up, companies are forced to create more compelling-looking products. That means better looking graphics, more vivid colors and unique packaging. Today’s narrow web printers are turning to new ink and coating formulas to improve efficiency and make products more appealing. Unfortunately, the properties of these chemistries cause problems such as UV ink spitting and accelerated blade wear. Where steel falls short, a next generation polymer doctor blade may be the solution in these applications.
UV Ink Spitting
UV inks are being used more often today to differentiate the look of packaging, speed up turnaround times, increase throughput and reduce downtime. The chemical properties of UV inks make them difficult for the printer to meter and control ink film thickness, however. UV ink has a normal viscosity of 5-7 times that of water and solvent-based inks, and its thixotropic properties (ability to thin out when agitated) make it transfer differently on press. This thicker consistency applies excessive pressure to the metering blade, often causing hydroplaning, or “spitting,” and defects in the printed image.
UV ink spitting is common with many flexographic printers who use steel doctor blades. Next generation polymer doctor blades have been successful in eliminating UV ink spitting problems due to their surface energy characteristics. To explain, a progressively lower surface energy, or dyne level, throughout the anilox ink delivery system allows the ink to easily transfer from one component of the anilox system to another. Otherwise, one component wants to hold on to the ink instead of letting it flow to the next. The characteristics of the new doctor blade material - its lubricity, rigidity and lower surface energy – give the blades a significantly lower dyne level than steel. This decreases the attraction between the doctor blade and ink and facilitates a more fluid transfer of ink to the plate.
Specialty Inks and Coatings Are Abrasive
Specialty coatings and tactile finishes such as glitter, pearlescent, textures and soft touch, are also being used more frequently to enhance the look of product packages. These chemistries are extremely abrasive to steel doctor blades and accelerate blade wear. Printers are consuming blades faster which increases downtime and costs. Next generation polymer blades are highly abrasion resistant and chemically compatible with all specialty ink and coating formulas; they last longer and minimize press downtime for blade changes.
As the industry evolves to keep up with the demands of manufacturers, printers are faced with new challenges in the pressroom. The new ink and coating formulas used to make products stand out on the retail shelf are difficult to meter with traditional doctor blade materials. Unlike steel, next generation polymer doctor blades can help reduce downtime and costs associated with UV ink spitting and accelerated blade wear.
About Flexo Concepts
Headquartered in Plymouth, Massachusetts, Flexo Concepts manufactures TruPoint doctor blades, the TruPoint QuikWash™ System and wash-up blades, and MicroClean™ dry media anilox cleaning systems. All products are designed to improve print quality and reduce operational costs for flexographic and offset printers. Flexo Concepts maintains distribution locations in North America, South America, Europe, Asia, Africa and Australia. For more information about the company and its products visit www.flexoconcepts.com.
Source: FlexoGlobal Blog