Screen Printing - Attractive, Versatile
The screen printing process adds "feeling" to package printing.
SCREEN PRINTING IS becoming synonymous with quality in package printing. Increasing the visual appeal of a package is something all brand owners strive for and screen printing helps in a way that very few other processes or substrates can.
With the ability to lay down up to 300 µm of ink in one pass, said John Costenoble, sales manager, Graphic Print Systems, Stork Prints America, Inc., comes the means to explore more creative avenues and the ability to increase the attraction to and perceived value of brand owners' products.
"Rotary screen printing is becoming increasingly important because end users—the brand owners who specify the packaging—are demanding increasingly higher standards of quality," he said. "The overall reason for this is that supermarkets, in particular, aim to offer as much choice as possible. So, in every category of food, beverages, household chemicals, and personal care, many products compete with each other on a crowded shelf to attract consumers' attention. With so much competition, the big fast-moving consumer goods makers focus on building strong brands. High-quality packaging must offer a high impact. It must stand out from the crowd."
Screen printing has no trouble distinguishing a package from others—both visually and tactilely. And, as Joe Posusney, marketing manager, Gallus Inc., explains, adding touch to a consumer's product-selection process can increase sales—what consumers can feel, they tend to buy.
"In the past, the No. 1 feature for screens has been the ability to lay down opaque coverage. Now part of the reason for its popularity is that it adds to the 'touch and feel' of a label," Posusney said.
"Adding a feature that attracts a potential buyer to touch the product has been shown in studies to greatly enhance the chances of the buyer actually purchasing that product. Brand owners know that an impulse purchase will occur 50 percent of the time when the buyer visually notices the product and upwards of 85 percent when they actually touch it," he said.
A welcomed addition
For the most part, adding screen printing capabilities isn't that difficult. According to Gallus, it doesn't take much to add screen printing capabilities on a Gallus press. Gallus screen units are of the "plug 'n play" variety and can be added to all Gallus printing systems and are interchanable on all stations. However, how easy it is to add screen units to other systems depends on several factors.
According to Costenoble, integrating screen units onto a press depends on 1) the market in which a printer is competing, 2) the role that screen printing will play in the printing configuration—"one or many units, in fixed positions or easily moveable on a sliding rail," 3) the type of drying system incorporated, and 4) the kind of press on which the screen capability is to be added.
For the most part, Costenoble said, screen units are being added to flexo presses, which have seen significant improvements in the last few years. But combination printing, in general, is seeing major growth with the aid of screen. "In developed label markets especially, there is a big wake up of hybrid presses today, and a move away from dedicated single-process printing," he said. "We at Stork Prints see a big move to flexo and rotary screen printing in-line. The flexographic process has enjoyed many quality improvements in recent years. One of the reasons for this is the development of enhanced plates and sleeves and, in the last 18 months, the arrival of direct laser engraving as a means of creating the image in one single pass."
Also, the increased availability of the light plug-n-play units and cheaper consumables have put rotary screen within the reach of smaller printing businesses and less frequent users, which helps feed the growth of the printing process. An example of its increasing popularity comes from press sales. At Gallus, Posusney reported, more than 95 percent of the presses delivered by Gallus in the last five years have included UV curing and screen printing capabilities.
The trendy screen scene
Packaging designers are doing their best to make most packages more functional and convenient, but also spectacular—in the truest sense of that word. Special effects, and those created with screen printing, help. Screen printed ink or overprint varnish can create a number of effects, making underlying graphics stand out or adding extra gloss or brilliance to the package, Costenoble said.
Screen's also made major contributions to the no-label-look label, "especially since it renders full coverage for greater opacity," Posusney said.
Another design trend where screen is assisting is in the realm of thermochromic ink applications. Thermochromic inks give consumers greater product information. "Thermochromic inks, which are sensitive to temperature change and are best printed by rotary screen, [are] a very creative way of providing information," Costenoble said. "There are both irreversible and reversible thermochromic ink varieties. Irreversible ink types would be used to indicate if perishable goods have been stored for too long or at too warm a temperature. This can be used to tell the consumer if the product is safe to consume.
"For wines, though, reversible inks would be an ideal choice for showing when a white wine has reached the correct serving temperature. … This could also be ideal for any market where consumers are that extra bit discerning. For instance, English 'traditional' ales or Belgian Trappist/abbey beers are best consumed, according to the cognoscenti, at temperatures a little higher than the standard refrigeration temperature. Fans of such brews may well appreciate an easy indication that serving time has arrived, too."
Another functional use of screen applications is Braille. Already, governments in Europe require Braille on pharmaceutical packaging and the Food and Drug Administration is considering a similar mandate in the United States, Posusney said.
Braille requires laydowns of about 250 µm, which is only achievable with screen printing. "In many European countries—particularly the United Kingdom, France, and Spain—brand owners and retailers are making efforts to communicate more product information to the visually impaired than just the triangular warning sign," Costenoble said. "Braille is being used for mentioning brand names, product information, expiry dates, and ingredients."
Screen printing and RFID
Screen printing is becoming more and more important in the manufacturing of RFID tags and labels. The basic smart label consists of a microchip attached to an antenna. There are three main ways that screen applications contribute to the production of smart labels, Costenoble explained: etching, plating, and printing.
Today, many RFID antennae are produced through an etching process where a UV etch-resistant mask is screen printed over the positive image of the plated copper or aluminum, leaving only the required metal for an antenna, Costenoble said. Another popular method of making an RFID antenna is plating where a copper-plate attracting layer is screen printed and then fortified with copper plating. As RFID technology evolves—sometimes progressing month-to-month—screen printing is being used to directly print the actual antenna using silver-based ink. "Rotary screen printing enables precision control over the thickness and width of the ink layer, whether you are printing the etch-resistant part or the conductive ink itself."
Market requirements require screen
Package printers have one main concern: pleasing their customers. But that's getting harder and harder to do as brand owners put more and more quality and creative pressures on printers. Screen printing can only help printers with these new requirements, Posusney said.
"Attractive labels play a key role in the demanding competition in goods presentations. New requirements are made everyday of the technical printing skills of label printers. And demanding requirements call for the appropriate printing techniques. Screen printing is the ideal process when high coverage, accuracy of detail, and color strength are required to achieve brilliant, high-grade pictorial effects," he said.
by Kate Sharon
Associate Editor
