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FLEXO Magazine : October 2013
IT’S ABOUT PEOPLE YOURS AND OURS A staple among prepress trade shops since 1903. After 110 years, we think it’s time for something new. dixiegraphics.com | (615) 832-7000 | email@example.com MEET THE TEAM AT DIXIE GRAPHICS Pat Meadows - President Matt Williams - Executive Vice President Scott Hillstead - VP of Operations Johnna Imel - Account Services Director BUSINESS DEVELOPMENT Jay Gieske - firstname.lastname@example.org Mark Coffman - email@example.com Randy Lee - firstname.lastname@example.org of intensity measurement and replacement control can lead to unstable plate quality. Unfortunately, extending the expo- sure time does not compensate for the loss of light intensity. Poor light results in poorly formed dots, because the polymer cannot harden correctly. Individual lamp aging results in uneven light emission and exposure between the lamps themselves. As previously men- tioned, emitted light from fluorescent bulbs is multi-directional and not focused, so even throughout the area of the bed, a plate does not receive even exposure. The inconsistency of bank light UV main exposure is also compromised by the plate’s position on the frame bed and the distance from the middle of the plate to its corners. inside tHe iMAger New, high definition flexo is able to resolve the issue of un- even light and, at the same time, eliminate the manual process- es of moving plates from one side to another—or one device to another. It does so by offering digital inline UV main exposure through an LED-array within the imager. The light source deliv- ers UV power density strong enough to assure full control over the polymerization process during main exposure. The technology involves programmable, variable control of the intensity and timing of the LED UV diode during the UV main exposure inside the imager. The digital control inside the imager can generate both round top and flat top dots on a job-to-job basis. This is done by programming variable power density levels of UV exposure. At the onset of exposure, flat top dots require stronger UV light exposure than round top dots. This burst forms the size and shape of the dot at the surface of the plate and acceler- ates the polymerization reaction so that the oxygen within the surrounding air is not capable of influencing it. This cre- ates a perfect one-to-one reproduction of the image without dot sharpening. When UV exposure is offered within the plate imager, there is no UV degradation over time and the expected lifetime is at least 5,000 hours (but probably much more). Because internal plate exposure delivers light through a simultaneous movement of the UV source over the plate by drum rotation, controlled by software, each area receives the same light quality and quan- tity. When a diode can no longer work, it will warn the operator and, ultimately, completely shut down—it’s either imaging at full power or off. This results in uniform dot shaping throughout the entire plate, a light source that is perpendicular to the plate surface and cool light that does not distribute heat to the plate. Thus, with digital UV exposure, plate departments can expect perfectly controlled, digital plate production. Human errors are reduced and plate consistency improves considerably. Here the quality, as well as the process, benefits. No longer does the plate department need to flip over a plate after back exposure, nor does a plate requiring a main exposure need to be moved from the imager back to the light exposure unit— it’s done in the imager. This means that there is less chance for operator damage—the kinks or folds that occur when a plate is moved. Some companies have built laser-engraving systems that directly engrave a flexo plate. In the past, the laser power has not been sufficient enough to deliver both quality and productivity: The time to produce a plate was significantly slower than that of ablation—roughly four times longer—and the quality had been deficient to analog photopolymer plate production. The more recent systems are promising but still slower and none have been able to replicate the full tonal ranges of 4000 dpi high definition flexo—systems that are con- stantly replacing gravure and offset. And, while they deliver on the promise of no solvents in plate processing, existing plate technology exists to deliver this for the ablation process. Whether a laser will be developed in the future to improve this particular process is conjecture. PAtH to Progress So, while the focus has been on improving the reproduction of images on a flexo press, there has been a concurrent effort of making the process of creating plates much easier, too. We have moved from creating molds of rubber plates to pretty much having the process handled automatically. Flexo plate produc- tion now generates consistent high quality that has an ancillary benefit: The plates are cost-effective and delivered much faster. About the Author: Ian Hole is vice president of market de- velopment for Esko. He currently serves on the FTA Board of Directors & FFTA Board of Trustees. 80 FLeXo OCTOBER 2013 www.flexography.org FTA Member Rate: $15 each or $40 for the set Build your foundation of flexographic knowledge with these practical pocket guides. An Introduction of Flexography Gain a clear definition of what flexography is and how it came to be the process it is today. This booklet reviews the fundamentals of flexography, inks & ink metering systems, substrates, types/sections of flexo presses, and more. Anilox Handling & Care Improper handling of anilox rollers can cost time, money, and press downtime. This booklet reviews the: types of anilox, proper handling methods, guidelines for care and maintenance, and more. Ink Handling & Maintenance Proper ink handling and maintenance is critical to the flexographic printing process. This booklet explains such topics as: ink types, ink prep (transfer, opacity, viscosity & pH), drying and curing, proper cleanup, and more. Get all the details at www.flexography.org/101 FLEXOGRAPHY 101 Booklet Series