LABEL PRODUCTION TECHNOLOGY TRENDS
Better...Faster...More Versatile

By Ivars Sarkans

The latest advances in label production technology were on display at the well-attended and vigorous Label Expo show during its bi-annual US run in September, 2002. As usual, some of the major technology trends were most evident in press exhibits. While the Label Expo 2002 show maintained its focus on the label market, the newest press models are no longer just for labels. Press suppliers are combining the advantages of the flexographic printing process with advances in precise web controls to expand their reach beyond labels to many other segments of the package printing market. Upgraded label press models can be very effective for short run printing of flexible cartons, films for product pouches and wrappers. The general packaging market trend to more private brands, niche specialties and regional varieties is creating demand for shorter production runs ideal for narrow-web flexographic presses. Some of the press suppliers exhibiting at Label Expo 2002 claim that their newest models can print materials ranging from .5 to 1.0 mil thick unsupported films up to carton board in the 18 to 24 point range. That is a material thickness range of .0005" to .024"!

Improvements in production methods and equipment displayed at Label Expo 2002 can be summarized under five major technology trends:

PREPRESS
Advances in plate materials and platemaking methods, including computer-to-plate (CTP) systems, are narrowing the traditional gap between flexo and offset print quality. Thinner plates and more precise dot formation with CTP systems have improved mid-tones and highlights printed on flexographic presses. Corton has introduced a new "high definition" unit for more consistent exposing of flexo plates from conventional negatives. The Cortron exposure frame uses reflectors to control the angle and uniformity of light across the plate, imitating the action of a laser plate imager. Cortron claims achievement of consistent 30 degree dot shoulder angles that give good highlights and prevent reverses from filling in. These are the same quality benefits offered by more expensive CTP systems.

DuPont has introduced a new version of the popular Cyrel® plate material called Cyrel Fast, which eliminates "wet" processing. After the digital Cyrel Fast plates are imaged in a CTP device and exposed to UV light, dry processing takes place in a special machine. Heat and pressure transfer photopolymer from unexposed plate areas to a roll of disposable developer material. The plates are then ready for the conventional post exposure and finishing step. Cyrel Fast plates are available in various sheet sizes, .045" and .067" plate height and two hardness levels.

Esko Graphics, Creo and other suppliers offer imagers for digital flexo plates, and some inventors are working on machines that use laser to "engrave" photopolymer plates in a single step. To improve laser imaging of flexo plates, Artwork Systems has expanded the capabilities of their Nexus RIP to include imagesetter calibration for precise smaller dots, hybrid conventional and stochastic screening, and creation of special cell structures in solid areas of flexo plates for smoother solids. Other RIP suppliers are also continuing to improve their products designed specifically for flexography.

PRESS HIGHLIGHTS
The label industry has experienced consolidation of press suppliers that has placed some long-established brands under new names. In one of the largest acquisitions, Comco became a division of Mark Andy. Heidelberg solidified its control of Gallus with a new management team from the parent company. Nilpeter acquired Roto Press and showed a new model at Label Expo 2002 based on Roto Press designs. PCMC (Paper Converting Machinery Company) acquired Webtron from Didde Web Press. Acquaflex, also previously owned by Didde, now operates independently under the Chromas name. Indigo has become a division of Hewlett Packard.

In the past, label producers had a choice of letterpress, flexo with water based inks and hot air dryers, and UV flexo. The choices have expanded dramatically, and now include mixed technology presses with options for integrated rotary screen, gravure, hot foil stamping, "cold" foil, and digital printing modules. The growing popularity of clear film labels and printing of packaging films on label presses has increased the demand for rotary screen units to apply a base coat of white ink. Rotary screen units are also used for various coatings and heavy ink coverage requirements. Most of the presses at Label Expo 2002 had a rotary screen unit option or a flexo station could accept a rotary screen insert.

Demand for machine versatility has led to development of more platform presses where any print position can be used for a variety of inserts. One of the technologies enabling easier design of platform presses is computer-controlled servomotors to eliminate conventional driveshafts and gears. When each station in a press is driven by a servomotor, computers can adjust web tension, print registration and other press functions very precisely as required by each printing and processing station or insert. A second benefit of servomotor drives is the ability for the same press to print on materials ranging from thin unsupported films to folding carton board. While some shaft-driven flexo presses claim similar capabilities, servomotor drives should give better web control and registration at the extremes of thin, stretchy and heavy materials that can be printed on a flexo web press.

Almost all label press suppliers have made design improvements to reduce setup time. In most cases, printing and die cylinders are easier to remove, replace and register. Several presses have built-in rails for sliding out each print unit for better access during makeready or to make print insert changes easier and faster. Some designs include "snap-out" inking units or special setup racks that roll up to a press and allow quick exchange of print and die units to minimize downtime and move wash-up tasks to an off-line workstation. To minimize wash-up time, DIP Co from Bloomington, Minn., offers paper and plastic ink pan liners and Keco Coatings, Indianapolis, Ind., provides Teflon-coated ink pans.

Several companies continue to build semi-rotary or intermittent feed narrow web presses in letterpress, flexographic and waterless offset (dry offset) versions. These machines operate as typical rotary presses when printing at maximum repeat length, usually 12". For all other (shorter) repeats, the presses switch to intermittent (stop-go) web feeding, and production rate varies with repeat size. The most important advantage of these presses is the ability to do most common label sizes with one set of cylinders, eliminating cylinder change time and inventory of different size printing and die cutting cylinders. Suppliers of these flexo presses claim setup time advantages, but in actual practice that would depend partly on operator plate mounting skills. The semi-rotary concept becomes particularly attractive in a short run offset press version that can use computer-imaged plates and change print repeat without changing cylinder inserts. The offset CTP process is simpler and plates are less expensive than conventional or CTP flexo plates. Servomotor drive technology holds promise for making semi-rotary press designs, which depend on precise control of web movement, more effective and productive. The tradeoff against semi-rotary press advantages is relatively low running speed, making these machines suitable mainly for short run production of labels.

Label press suppliers are gradually boosting maximum rated press speed from the 500 feet/minute level common in the 1990’s to 750 feet/minute. The higher flexo press speeds are partly a response to the increasingly competitive label industry environment, package printing demands and higher speeds of web offset presses configured for labels and packaging. At the same time, advances in flexo press web tension controls, inking unit designs and dryers make it easier to achieve the higher speeds. In actual production, the growing use of rotary screen units, hot foil stamping, "cold" foil application and other special on-line modules limit the running speed attainable on many jobs. In labels, like most other segments of printing, short runs are increasing and productivity gains from quick setup can be far greater than from high rated press speeds.

Among the more unique presses at Label Expo 2002, the Mark Andy/Comco ProGlide model appears to offer an almost unlimited range of printing, coating, drying and processing options for extremely complex and demanding applications in labels, tickets with security features and packaging. The Gallus RCS-330 platform press had a dual plate cylinder "flying" imprinter that allows plate changes without stopping the machine. The Omet VaryFlex model has no print repeat restrictions imposed by gears. The press uses servomotor drives and different diameter plate sleeves to achieve any desired print repeat from 11.5" to 33.0". Another unique design for an infinitely variable print repeat offset press was shown by Drent Goebel in partnership with RDP Marathon. The Drent Goebel technology demonstration featured easily changeable low-cost plate and blanket sleeves in a new print tower design which eliminates the need for costly and heavy print cylinder inserts. Plate and blanket sleeve shafts and form rollers adjust automatically to each different sleeve diameter. Commercial availability of Variable Sleeve Offset (VSO) technology presses is planned for the second half of 2003.

DIGITAL PRINTING
At this early stage of digital printing in labels, run speeds of digital color presses are far below typical flexo press speeds, but image quality of some machines is comparable to good flexo printing. Given their advantages in setup time and variable image printing, digital color presses will have a growing presence in the label industry, as evidenced by their increased presence at every successive Label Expo.

The Indigo Division of Hewlett Packard introduced the new WS-4000 digital web press. The machine can print up to 7 colors, including a white base plus six process inks (CMYK, orange, violet) on webs up to 13" wide. Print repeat is variable from 8.85" to 18.5". Production rate depends on the number of colors printed, with 4 colors at 52.5 feet/minute. The WS-4000 was demonstrated in-line with an Omega Systems Digicon 330 finishing unit consisting of stations for flexo varnishing, over-laminating, "cold" foil stamping, die cutting, trim removal and rewinding. Other in-line finishing options include hot-foil stamping and sheeting. At Label Expo 2002, Indigo reported sales of seven WS-4000 machines, counting the early test sites.

Another major digital printing introduction was the Mark Andy DT (digital technology) press utilizing ink jet technology. The SPICE (Single Pass Inkjet Color Engine) unit was mounted on a Mark Andy 2200 press base in combination with flexo printing stations and a Las-X laser die cutter. The SPICE unit can print 4 process colors, with future plans for 6 colors, using pigmented UV inks. Rated speed I80 feet/minute. The DT press is a joint development of Mark Andy and Dotrix (formerly Barco), with Xaar designed ink jet heads produced by Toshiba. Digital print quality is rated as equivalent to 150 line screen flexo.

Digital printing and other press finishing technology advances will continue to create new market niche and product opportunities for label suppliers. This includes the many forms producers who have expanded into labels and can use the same equipment to reach some segments of the package printing market. Both forms and label press suppliers have sold machines for a combination of label and packaging products, signaling a growing overlap between these specialties and opportunities for innovators and short run specialists.

Ivars Sarkans is president of consulting firm Sarkans & Associates of Los Angeles, California and a long time contributor to DMIA publications. He can be reached by telephone at (323) 221-7791 or by e-mail at isarkans@sarkans.com. His Internet address is http://www.sarkans.com

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PRESS COMPARISON CHART
Label Expo 2002

Note 1: Static technology exhibit of print tower at Label Expo 2002
Note 2: Codimag and Omet presses are sold in the US by Matik North America (www.matik.com), West Hartford, Conn.

Abbreviations
FPM - lineal feet per minute
IPH - press impressions per hour

This chart is limited to full-scale presses or print units actually present at Label Expo 2002. It excludes several suppliers that had only press literature at the show (Xeikon, Allied Gear, Arpeco), desktop digital label printers and thermal transfer ribbon printers.

Most of the suppliers listed in the chart offer multiple models, web widths and a wide range of press options. Practically all press models are available with a web cleaner, corona treatment, die cutting stations, trim rewind, roll and sheet delivery and hot air dryers. With exception of the most basic label printing models, flexo presses can be equipped with UV dryers.

All trade names and trademarks used to identify products, models and features in this chart are the property of the respective suppliers.

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