Esko (www.esko.com) has extended the application of its HD technology with the introduction of HD Letterpress, a plate imaging technology for metal-backed plates. The new technology allows brands to print plastic and metal packaging such as for example beverage or aerosol cans with a wider tonal range, along with a significant increase of detail and improved productivity.
“If your can does not stand out in the store because it does not look good, your investment in product development and packaging design is largely wasted because consumers make their final buying decision mostly at the point of sale,” says Thomas Klein, VP Hardware Business at Esko. “That is why Esko developed HD Letterpress, which utilizes Esko’s HD technology that is adopted by more than a thousand flexo platemaking facilities around the world. The primary difference is that a special digital Inline UV curing system was developed for steel-back platemaking, and that the Esko CDI imager is delivered with a magnetic drum.”
Applications like metal cans and plastic tubes are often printed on dry offset presses. Dry offset printing for conical/cylindrical packaging however brings some unique challenges when it comes to achieving the highest print quality. Unlike any other print process, dry offset places multiple inks, ‘wet-on-wet’, on a common blanket. That image is then transferred to the packaging to be decorated. “The ‘wet-on-wet’ ink transfer presents several printing problems that must be properly addressed for a job to look and run well. Smooth highlights and clear fine lines or negative text – large and small – have been a problem to achieve in the past. With HD Letterpress, Esko is extending its HD concept of higher quality, in order to resolve some of these issues”, explains Klein.
Digital Inline UV head at the center of innovation
The technical innovations of HD Letterpress platemaking are the digital Inline UV head with a directed UV LED light source and 4000 dpi high-resolution imaging.
Digital Inline UV plate exposure via UV LEDs assures imaging quality is consistent throughout the entire plate because each portion of the plate receives the same amount of UV light. By engineering the UV light output to the characteristics of the steel backed polymer plates, HD Letterpress allows steeper shoulders of the printed dots – ensuring much finer highlights and truly smooth vignettes in print. Because the UV exposure is now integrated within the imager rather than on an external light table, any waste due to dust, finger prints or daylight exposure is eliminated.
The 4000 dpi high-resolution imaging optics offers three times more pixel data than with standard 2540 dpi resolution. Thanks to this improvement, the printed image is more precise with sharper lines and has easier to read positive and reverse text. Screening dots are more clearly defined and better shaped because they are built with more pixels. HD Letterpress delivers much finer highlights with smooth gradients over the whole tonal scale, without any stepping. Because it delivers highly improved image quality and detail sharpness compared to standard imaging, it helps a brand to stand out on the shelf.
Increasing production and reliability
Apart from the much improved image and plate quality, the Esko HD Letterpress system also offers high productivity and reliability throughout the entire production process. The HD Letterpress CDI is up to six times faster than traditional direct laser engraving technologies when it comes to imaging and exposure. This makes it one of the most efficient and highly productive processes currently available on the market. It also comes without the environmental issues of removing significant residue, additional space requirements and costs.
Additionally, in the pressroom ink transfer is dramatically improved, so press operators don’t have to wash out plates as often as when using standard plates. The printer/converter receives highly consistent plates, from image to image and plate to plate.
“Esko HD Flexo has revolutionized the way flexographic printing is seen in the packaging marketplace,” concludes Klein. “In the same way, HD Letterpress will dramatically improve dry offset printing. It will make life easy for brand owners and print buyers without compromising on quality. And, because it is field upgradeable for those who already own an Esko CDI Letterpress imager with magnetic drum, it does not necessarily require a significant capital equipment investment. For anyone who requires competitive, high quality printing with greater productivity and easier use, Esko HD Letterpress offers the answer.”
Esko HD Letterpress is available immediately worldwide. HD Letterpress will image plates manufactured by a variety of leading plate vendors, giving users the freedom to select their own plates and allowing them to image on a wide range of plate sizes and formats. With an Esko CDI plate imager, it is possible to image any type and brand of digital ablation letterpress plate.
Esko will demonstrate HD Letterpress at Labelexpo Europe 2015, September 29 till October 2 at the Brussels Expo in Belgium – stand 4C20.