The Benefits of Marrying LED Plate Exposure with ITR Sleeves

In the last few years, LED plate exposure has gained greater acceptance in the areas of plate consistency, printing minimum dots, flat top technology and improved screening.

Further, organizations with Key Performance Indicators (KPIs) that help minimize their environmental impact have embraced LED technology as an effective way to contribute to their objectives.

However, LED technology is not new to the flexographic industry. In fact, it has been around for nearly 10 years, since the early 2010s, when flat top dots were just taking shape and being perfected from multiple manufacturers and many industry experts.

It was 2013 when E.C. Shaw Co took ownership of its first LED exposure unit. Subsequent investments have broadened our portfolio and reaffirmed a commitment to LED plate making. After nearly 10 years of “exposure,” LED is finally gaining recognition as a preferred methodology for plate exposure. When matched with in-the-round (ITR), it becomes yet another game changer for the flexographic printing industry.

Nod to Past

For years, those of us in the flexographic premedia and printing industry have fought for plate consistency. From the days of grinders and rubber plates to the warmup and non-stop measurement of UV banks, flexographic printing has struggled with this variable in our collective systems. It can be argued that for a long period of time, UV bulbs were not even recognized for their contribution to the inconsistencies found on press. In essence, UV was a part of the problem.

As an example, it is widely accepted that early flat top dot technologies had an enormous impact on the flexographic industry. In fact, the flat top dot was one of the most important advances in flexographic printing in recent memory. It forced all of us to up our game. It challenged us to rethink what was possible and reignited passions within the industry. Print quality was substantially improved through flat top and cost reductions were realized in the areas of ink savings—almost eliminating the dreaded “double bump” whites and the increased use of ink extender in formulas (to name a couple).

Overnight, transitioning jobs from offset to a more cost-effective flexographic solution became routine. Flat top dots clearly provided a win-win for printers and premedia shops alike. More importantly, it was a definitive win for flexography, an industry that was being threatened by lithographic printing and some felt would be replaced by digital printing in a relatively short time frame.

During this period, many flat top technologies entered the industry. However, even with the vast improvement that printing with flat top technologies offered, most of the new technologies continued to rely on UV exposure as part of the manufacturing process. Better transitions to zero, enhanced screening and flat top dots were achieved, but the nature of UV bulbs made (and still makes) it difficult to achieve consistency from plate to plate.

Enter the world of LED. It’s like flat top on steroids. Not only are we able to reproduce surface screening patterns 1:1 on solids and halftones, but transitions to zero can also be further improved with minimum dot optimization. Now, with LED, we can eliminate the UV variable. LED allows you to drive plate consistency not just day to day, but year to year. Add a healthy dose of environmentally friendly bulbs to replace the mercury from days of old and the result is another win-win for our industry.

ITR Now

Similar to the slow acceptance of LED exposure, ITR sleeves have been in the flexographic printing industry for approximately 10 years now and have slowly found a niche in certain markets over time. Once thought of as an expensive and unnecessary replacement for flat mounting plates, ITR sleeves have been proven to be a cost-effective alternative.

The following trends illustrate the point:

• Press manufacturers continue to push the boundaries of press speeds, some of which even require ITR sleeves to eliminate plate lift
• Other presses are geared for quick changeover, using sleeves to minimize downtime
• Graphic designers continue to reinvent packaging by pushing the envelope with challenging graphics and requirements for continuous print
• Production managers are in relentless pursuit of reducing changeover time and minimizing setup costs

With plate life in the tens of millions of impressions, long-running jobs continue to demonstrate the cost effectiveness of utilizing ITR sleeves. These seamless sleeves have clearly found a home addressing these needs.

When Worlds Collide

There are, however, challenges when these two worlds collide. The challenge of matching a state-of-the-art LED plate with an ITR sleeve that has been exposed with UV bank can be problematic. As discussed, not only can flat top and HD dots be vastly different, but UV and LED exposure can lend itself to adding another variable to the printing process.

Further challenges occur when jobs normally printed with LED flat plates are transitioned to ITR because the volume dictates a more cost-effective ITR approach. Although HD at 4,000 dpi is good, LED flat top has proven itself to yield better ink densities and a better min dot. Furthermore, the inconsistencies of UV exposure will not provide the desired 1:1 match in surface screening, the transitions to zero found with LED, nor the consistency from plate to plate.

Future Is Today

Fast forward to today, where next-generation LED technology is coupled with an ITR seamless plating system. At E.C. Shaw Co, the result is the only next-generation ITR LED exposure unit in North America. And it is yielding tremendous results. Typical comments are:

• “The reverse print could be the best I’ve seen.” – Wide web printer
• “The solid ink coverage from the LED looks great. No mottling.” – Wide web printer
• “You beat your competitor with these ink densities. Impressive.” – Film printer
• “Opacity increased by 12 percent with a single hit of white.” – Film printer
• “Nice. How did you get the varnish to lay down so thick for us? It’s tactile.” – Narrow web printer

The game is changing again. Converters are marrying all of the benefits of LED with the advantages of ITR, embracing six letters that change everything. Critical features of the blending of technologies include utilization of a LED flat top, imaging at 4,000 dpi, application of 1:1 pixel+ microcell/surface screenings, better consistency and elimination of plate gaps. Production teams are attesting to multiple benefits:

• Better transitions to zero
• Greater solid ink densities
• Sharper/crisp dots
• No plate lift
• Faster press speeds
• Reduced makeready times
• Environmentally friendly
• No plate cupping
• Better print quality
• Longer plate life
• Zero mounting tape costs

Some have said that the future of photopolymer plates is in the plate material itself and that materials that are inherently capable of producing flat top dots are likely to drive innovation. Others have indicated the future will be driven by LED exposure units and the consistency that lies therein. Still others have driven innovation through software, measuring devices, ancillary products/services or integrated printing presses.

In each case, the flexographic industry continues to reinvent itself. In each case, we challenge each other to do better. And, in each case, we adapt to the changes we are faced with. Regardless of our approach, we embrace change and look for new ways to improve the industry we love—flexographic printing. True to form: L-E-D-I-T-R are six letters that change everything!