No frills: small-character coders stick to the practical: developments in coding and marking equipment bring higher speeds, clearer codes and lower costs

Food & Drug Packaging, August, 2004 by William Makely

New developments in packaging often center around the package's appearance--shelf appeal, brand projection and even the feel of a package that can advance its sale to consumers. We're used to seeing technology change because it affects the way the package looks.

Not so, the changes taking place in coding and marking equipment. This segment of packaging technology is strictly practical.

Demands for traceability trickle down to coding equipment manufacturers through customers regulated by the Food and Drug Administration (FDA). The result: a demand for coding equipment that is reliable, maintainable and produces clear, readable codes. No frills, no bells and whistles. Just results.

Advances in the three most-used coding methods--laser, ink jet and thermal transfer--simplify equipment operation while still delivering the flexibility needed for today's shorter run, higher changeover packaging lines.

Laser

One of the obvious benefits laser coders offer over ink jet competitors is that they use no ink--no ongoing expense for consumables, no potential for clogging or spilling. But the newest developments in lasers have other advantages as well: clarity of marking, high speed and low maintenance costs.

The Weber Marking Systems SolarJet HD vector laser coder is capable of marking up to 1,000 characters per second at product delivery speeds of up to 1,060 feet per minute. Text, bar codes and graphics as small as 0.02 inches high can be marked on substrates like paper, cardboard, foils, coated metals, plastics, wood and glass. And SolarJet is specifically designed to operate efficiently in harsh venues like the damp environments found in beverage filling operations.

Domino Amjet's $300 Series C[O.sub.2] lasers can mark two-line codes at rates of up to 500 feet per minute also in harsh environments like high-humidity bottle filling lines. The series includes the S300B, designed specifically to mark polyethylene terephthalate (PET) bottles with high-contrast codes at rates of up to 1,000 bottles per minute. These lasers also have the power to mark glass effectively. They feature a compact, lightweight head that needs minimal maintenance.

Targeted more to medium-speed production lines are the Markem Corp. SmartLase line of C[O.sub.2] laser coders and the Linx Xymark 300SL scribing laser coder.

One recent development in laser coding uses an entirely new technology. DataLase[TM] is a nontoxic and environmentally friendly ink, coating or substrate additive developed by Sherwood Technology Ltd. in the U.K. When marked by a low power C[O.sub.2] laser, DataLase undergoes a simple chemical color change to create an image that is stable and has high contrast.

Because images are created by laser activation, there are no consumables used during online coding. Images are sharp and production speeds high. By using a low-power beam, imaging occurs faster than with a high-powered beam which burns away the top layer of color to create a white code. DataLase's low power C[O.sub.2] laser is able to apply two lines of 25 alphanumeric characters at speeds of 350 feet per minute.

A unique feature is that images can be formed through polypropylene (PP) and polyethylene (PE) films, allowing the image to be permanently embedded within laminate layers while still being formed online rather than preprinted.

Ink jet

Ink jet coding technology today falls into two major categories: the traditional continuous ink jet (CIJ) coders that draw on a remote store of ink, and newer systems that use more localized ink supplies, like Hewlett-Packard's thermal ink jet (TIJ) and the Diagraph Wax Jet systems.

New technological developments among continuous ink jet coders focus heavily on overcoming the long-running reservations about such equipment--that lines and heads tend to clog with dried ink over long overnight or weekend breaks, requiring valuable production time to restore them to operating status on startup. Whatever sophisticated new capabilities an ink jet coder offers--an ability to print any ink on any substrate, full integration into line control systems, multiple language capability for global compatibility--the deal killer often still is, "Can I start it up and shut it down without hassle?"

The new Hitachi PX Series of CIJ coders features an innovative ink circulation system that helps reduce fluid evaporation and achieves a low cost of operation. At the same time, the coder's nozzle and gutter are automatically cleaned before shut down, so no special cleaning procedures are required of operators either at shutdown or startup. The combination leads to greater productivity.

Diagraph's Linx 6800 Spectrum coder, which was introduced last year, can be shut down for up to four weeks, then started up again without any maintenance because software automatically calculates the duration of each shutdown and adjusts ink circulation when the unit is turned on.

Advancements like these have improved CIJ performance and buyer confidence. The real revolution in ink coding, however, came when Hewlett-Packard (HP) introduced its TIJ system, which incorporates the ink and the printhead in one cartridge, just like the cartridge for a desktop ink jet printer. The cartridges can be replaced simply by snapping them in and out of their carriers. TIJ systems are clean, with everything in one unit. There are no long feed tubes to dry out and clog during downtimes.