Flexo Prepress Technology

By Catherine Diamond, Associate Editor | March 8, 2012

Prepress technology can make or break image quality for a converter. Here's how manufacturers have kept pace with broad changes in flexo presses, met customer requirements and kept it eco-friendly.

Developers of prepress technology for the flexographic market have simple goals: to help their customers create crisp images in a streamlined process that they can repeat, again and again. Accomplishing those goals, however, is no easy task. It requires an understanding of the entire print process from start to finish, including its challenges, and of the science behind color.

Over the last 15 years, the steady shift from traditional plate systems to digital systems has been considerable. The change has not only helped many converters to streamline their processes and improve image quality, but it has also helped them to implement sustainable practices and reduce their impact on the environment.

At one point, the decision to go digital was based largely on numbers. It is a significant investment – for some smaller companies, perhaps prohibitively so – and not one that converters were likely to make at the height of the recession. However, as the economy has begun to turn around and converters’ bottom lines have bounced back from rock bottom, investing in digital prepress technology is more attainable and, according to some, very worthwhile.

Making the investment
Just a few months ago, The Label Printers, Aurora, IL, USA, made the decision to invest in digital prepress technology and plates. According to Joe Kane, prepress manager at The Label Printers, the decision was a long time coming.

A screenshot of Esko Studio
“We had been looking into digital for more than five years. At first it was the attraction of the quality and consistency that it offered. But that wasn’t quite enough to justify the large expense of switching,” he says. “Then, with the added benefit of thermal processing reducing the cycle time of the platemaking process, things became much more attractive.”

Despite the attraction to digital prepress and plates, The Label Printers still weren’t yet ready to make the investment. “It wasn’t until we really started in the LIFE (Label Initiative for the Environment) program through TLMI (Tag and Label Manufacturers Institute) that
all the environmental benefits really tipped the scale,” says Kane. “Being able to remove all of the chemicals and solvents used in the platemaking process, as well as increasing the quality and doing it faster, made all the difference.”

The company decided to invest in Esko hardware and software technology, which Kane says was the right decision. “I want to give especially high marks to all of their training staff and phone support team. They have all been instrumental in making the transition as smooth as possible.”

Kane says that the company has seen two significant changes in their printing process and quality since investing in digital. “One huge factor is that if there’s an issue on press, we no longer have to lose half a day remaking plates,” he says. “With the faster turnaround time, we are able to be up and running again in under an hour.”

Kane adds: “With the addition of a new color proofer that was calibrated at the same time the new plates were, we are significantly more accurate and predictable when it comes to color.”

Environmental and quality concerns
The Label Printers is not alone when it comes to environmental concerns. Though digital platemaking is less taxing on the environment than traditional platemaking methods, it is not perfect. But converters have voiced their concerns, and suppliers have responded with solutions.

“This industry is always looking for better ways to leave less impact on the environment without sacrificing quality,” says Jessica Harkins, technologies manager at Anderson & Vreeland, Arlington Heights, IL, USA. “In the past few years we have seen this to be true with the interest and increased use of water-wash plates and alternative eco-friendly solvents.”

Terri Stewart, marketing manager at Flint Group Flexographic Products, Charlotte, NC, USA, says one of the company’s focuses is to increase processing efficiency through equipment automation and reduced waste of consumables. “With that in mind, our range of nylosolv plate washout solutions are formulated to be efficient and environmentally-friendly for safe and fast processing of photopolymer printing plates,” she says. “In 2008, we commissioned and published an independent Eco-Efficiency3 analysis that demonstrated that by proper distillation and reuse of washout solution, the impact to the GWP (global warming potential) of solvent platemaking is nearly equal to or less than the GWP of thermal platemaking. 

“Most recently, 2011 marked the North American debut of Flint Group Flexographic Products’ Plate Waste Recovery Service, whereby 100 percent of all used and unused plate material, coversheets and cushion tape is collected and converted from waste into energy,” she says.
According to Heather Barrett, director of marketing at MacDermid Printing Solutions, Atlanta, GA, USA, “Sustainability is an issue in packaging that’s here to stay, especially as more and more retailers and consumer packaged goods manufacturers push on their suppliers to help them meet their sustainability goals.”

A label made using Esko Studio Visualizer

MacDermid, Barrett says, has taken several steps to ensure that their customers meet those goals. “We are continuously seeking to develop technologies with smaller environmental footprints. For example, we recently developed an EFC (Environmental Footprint Calculator) that enabled us to use LCA (Life Cycle Assessment) data to model different types of platemaking: solvent, thermal and liquid. This tool showed us that thermal platemaking, via MacDermid’s LAVA Plate Processor, and liquid platemaking were much more environmentally friendly than traditional solvent sheet platemaking. We are continuing to innovate in these categories by developing additional applications for our thermal and liquid plate processors.”

Larry Moore, director of Esko software services in North America, says that the push for sustainability has challenged people to produce labels more efficiently. That efficiency, he says, starts at the design level. “Being able to create virtual 3D mock-ups and to communicate and collaborate with customers across the web eliminates hard copy proofs and prototypes, along with shipping costs,” he says. “Design tools — particularly structural design — help make packaging more appropriate to the products they are holding rather than using a generic box that is loose and not as protective of the product as it should be. The drive to make the package more functionally efficient also makes it more environmentally efficient.”

Digital press and prepress changes
In addition to responding to converter and consumer concerns about the environment, manufacturers of prepress technology have also had to respond to the overall changes in digital press technology.

“Some of the advancements in prepress wouldn’t be possible without faster, more accurate presses, capable of higher end work,” says Barrett of MacDermid. “Without these press capabilities, it wouldn’t matter whether we were able to develop plates with smaller dots and fine line screens, because that improvement wouldn’t show up in print. So, as presses have gotten faster and more accurate, we have developed prepress technologies that are faster and more accurate as well.”

Stewart, of Flint Group Flexographic Products, echoes Barrett’s sentiment: “As higher print quality demands and other ink and press achievements have created a trend toward the use of harder flexo plates, the issue of plate rigidity and life can arise on small repeats,” she says.

“For Flint Group, these types of challenges have been met with new, refined product innovations, such as our nyloflex FAB and nyloflex FAM digital plates. Regarding the need for quick changeovers, our response was the hard rotec label sleeve, which was specially developed for narrow web presses. These sleeves offer consistent printing properties through high-dimensional stability, and long-lasting and continuous register accuracy.”

Greg Mais, sales representative at Sam Chung and Associates in Mississauga, ON, Canada, a prepress and plate supplier to the wide and narrow web industry, says that the future of flexo prepress technology will undoubtedly include ITR (in the round) sleeves.

“Within the last ten years the quality of flexo printing has made considerable progress,” he says. “The digital plate has increased the color gamut, contributed to higher screen counts and, with better plate materials, has contributed to a higher quality of clean flexo printing.”

“Using ITR sleeves can improve productivity and quality by increasing press speeds between 10-30 percent, eliminating the need for plate mounting, and by offering continuous designs, simplified trapping, better register and improved consistency,” he says.  

Thin is in?
Another aspect of prepress technology that has changed in recent years is plate thinness. According to Paul Zeinert, direct engraving product manager for Anderson & Vreeland, it is a trend that is slowly being embraced by converters in North America.

“Thin plates are very popular in Europe and are slowly gaining acceptance in the United States. Their popularity will increase as new presses enter the marketplace,” he says. “Adoption of ‘thin plates’ is a slow process due to predefined undercuts on press. Many customers are hesitant to buy a new press specified to use 0.045 or 0.030 plates when they are already using 0.067 material in-house. Having one press using thin plates makes scheduling more of a challenge, as imaged plates are no longer universal and are press-specific.

“That being said, there are many advantages to using thin plates once the obstacles are addressed. Benefits include handling, processing time, weight (less expensive to ship), mounting (less plate lift on narrow cylinders) and equal – if not improved – print quality,” he says.

MacDermid’s Heather Barrett says that thinner plates have a sustainability advantage because “quite simply, it requires less photopolymer to make a thinner plate than a thicker one.”

In addition to the eco-friendly characteristics of thin plates, Barrett says that there are also considerable advantages in regards to platemaking time. “Thinner plates can usually be imaged and processed more quickly, since less washout time and dry time is needed. This results in higher efficiency for the plate maker,” she says.

“Additionally, thinner plates tend to have a higher effective durometer, and historical print data tells us that a higher effective durometer results in less dot gain. For those in the narrow web segment, especially the prime label business, less dot gain results in better print functionality. They also work well within the narrow web segment because narrow web presses tend to run on smaller print repeat lengths, so thinner plates wrap around the press cylinder more easily. They’re more limber, so there is less opportunity for edge lift,” she says.

“For years, the narrow web market was limited to using an 0.067 plate,” says Moore, of Esko. “Over the past few years, thinner plates have become available in 0.045 and 0.030 thicknesses. These are more capable of carrying more detail than thicker plates, offering better printing quality because it is easier to control the plate depth. These plates typically have a higher durometer, so they hold greater detail when printing on labelstocks. All of this is assisted by newer presses that are designed and capable to work with thinner plates.”

Flint Group’s nyloflex NExT LED bar
The future of flexo
Many flexo printing experts believe that the trend towards digital will continue, much to the benefit of converters’ customers and end-use consumers.

“In the past, ‘flexo’ was synonymous with 3 percent minimum dot, hard break and heavy dot gain,” says Harkins of Anderson & Vreeland. “Now it’s possible to hold 0.5 percent dots when using hybrid screening technology, such as HD Flexo from Esko, which can smooth image breaks and improve print quality. This vastly promotes tonal range and the ability to reproduce fine images. In the future, the process will only become more automated and streamlined – leading to a full process that is increasingly digital.”

Stewart of Flint Group Flexographic Products believes that plate manufacturers will continue to respond to advancements in prepress software technology with the same urgency that they responded to changes over the last decade.

“For narrow web, where quality is already at a high level compared to other flexo markets, the future will lie in refining technology and pushing the envelope even further,” she says. “A world where 200-plus LPI and 1 percent printed dots are the status quo is not far away.”

According to Moore, the most significant change he’s seen in recent years is data files for many applications being stored on remote servers and shared throughout the enterprise.
“In the future, prepress technology will be in the clouds – quite literally,” he says.