Bert Moore

Introduction

A quick True/False quiz:

1. Direct thermal labels fade quickly in the sun or warehouses.
2. Ink jet cannot be used to direct mark U.P.C. and other high density symbols.
3. Matrix impact printers aren't used for bar codes any more.
4. Thermal transfer printers are very expensive.
5. Laser printed labels aren't very durable.

If you answered "True" to any of these questions, it's time to rethink your assumptions. It's not so much that there have been major changes in printing technology overnight, it's that incremental improvements have crept up on you. Improvements in consumables and software, as well as hardware, have changed the face of bar code printing.

Today, there are more viable choices than ever. Selecting the right printer(s) for your needs means understanding where bar code printing fits within your business processes.

A bar code printer sits at the end of the labeling process and the beginning of a bar code tracking and identification process (whether for internal or external purposes). It also may play a role in other business processes. These processes vary from company to company, application to application. While virtually all printers can product good quality labels, some specific products or technologies may better meet your process requirements.

Let's take a quick look at these processes to better understand which printing technologies are appropriate for their needs.

It's important to recognize, however, that software, media and consumables play a significant role in overall printer performance and quality. The same printer using differing grades of consumables may produce dramatically different results. In the following discussion, it is assumed that the appropriate consumables will be used. Label design and printing software can significantly affect (for better or worse) the speed and flexibility of any printer.

End Use

Durability

Clearly, the ultimate goal of any bar code labeling program is to produce a symbol that is readable throughout its anticipated life. In some cases, it's a one-use symbol designed for internal use (say, a pick ticket). In other cases, it might need to be read hundreds of times over a five to ten year period (for asset tracking, for example). It might be read with a contact wand or a non-contact laser; it might be used in an office environment or shipped cross-country on a pallet. Durability and symbol quality are areas where consumables play a critical role.

Application Standards

With rare exception, bar code printing must conform with some standard: an industry standard, a customer specification, or an internal corporate standard. This is the first place to look for symbol use requirements. These standards typically mandate symbology, placement and layout, printing dimensions, quality, and durability.

Graphics

For some applications, graphics must be included -- whether it's a company logo, a picture of the product, or some other graphic element. With the trend to higher resolution printing and the availability of TrueType fonts for most technologies, these requirement can be met relatively easily. However, these may merit additional consideration when evaluating the label printing process.

Color

Adding color to a label for aesthetic appeal or for corporate logos is increasingly popular. For applications where pre-printed label media is not an option (because of quantity, control, or turn-around time issues), some printers can produce color -- from limited colors in pre-determined locations all the way to process (4 color) images. Trade-offs here are typically in equipment and consumables costs.

Label Production

Speed

Actually, there is no such measure as "speed" when it comes to label printing. The three meaningful measures of printer performance are: time to first label, time from first to second label, and thruput. (See: Printer Test article for proof of this assertion.)

For batch printing, thruput is the key measure. Graphics, TrueType fonts, variable data, and other elements that must be downloaded may increase the time to first label -- but for a print run of, say, a thousand labels, the difference is inconsequential.

For demand printing, time to first and second labels is more important. These, along with line speed, are the critical measures for printer-applicator or direct-marking applications.

Again, software has a lot to do with these measures and printer performance may vary depending on software used.

Communications

There are two issues involved in communications: how data is communicated and the data source(s). Both of these issues are dependent on the particular application needs.

The growing popularity of dedicated Windows drivers for thermal printers means that all elements of the label will be downloaded as a single graphic. For these applications, parallel ports are becoming more popular to increase data communications speed.

On the other hand, the increasing use of client/server applications may require a networked solution. Today, more Ethernet-capable printers are available that can be installed as network nodes.

Printers are also increasingly capable of accepting inputs directly from scales, cubing systems, and other sources.

Quantity/ Waste

How many labels need to be produced in a given time period is a major factor, although there are some business process considerations here as well.

For low volumes, inexpensive low-thruput printers may be the answer. However, some companies prefer multi-purpose printers (laser, matrix) which can be used to produce reports and other material when not printing bar code labels.

For high volumes, some companies prefer several lower-thruput printers to provide system redundancy. In other cases, a single high-volume printer is preferred. This is typically a business decision.

Depending on the application and the specific printer, more media may be wasted than used. Multiple short runs, particularly on different label sizes, may mean significant amounts of waste with some printers.

Ease of Use

Replenishment of consumables, printer controls, and overall design all play a part in ease of use as well as productivity. Take a good look at the paper path (straighter is better), the ease (or difficulty) of replacing label media and ribbon/ink/toner (if applicable), cleaning and maintenance, and setup.

Consider, too, whether some of these factors are really significant in your application. For example, several thermal transfer printers now come with hinged covers -- making it much easier to replace consumables in tight spaces. Is this significant? It all depends on your physical space.

Printer Types

There are still only four basic printer types: thermal (direct and thermal transfer), laser, matrix impact, and ink jet. What's changed are the capabilities and the options.

Thermal / Thermal Transfer

Long known for producing crisp, high quality images, thermal printers (particularly thermal transfer) were also known as "high ticket" items. That's changing. Economies of scale and decreasing cost of computing horsepower are bringing the price of thermal transfer printers down.

Eltron, for example, has a line of relatively capable but low cost (and admittedly low volume) thermal and thermal transfer printers in the range of a few hundred dollars. Low volume printers may be ideal for relabeling situations even if a high volume printer is used for the primary application. Eltron's lowest cost Companion printer can even be daisy-chained.

High-end printers now offer more power and features for about the same price as less capable printers a few years ago. Wide throat printers (6 inches and above) are increasingly available without the punitive pricing of early models.

Thermal print resolution is headed in the opposite direction of price -- it's going up -- with Intermec and others offering 400 dots per inch (dpi) resolution -- easily competing against standard laser printers. For on-demand production of very high density symbols, thermal is still the technology of choice.

Ease of use is also improving.

Tharo has just introduced the Gemini printer with no resident bar code or text fonts. Everything is controlled from a dedicated Windows driver that allows accurate printing of bar codes in standard Windows programs (from spreadsheets to word processing documents).

Monarch's new 9820 and 9830 center all consumables for easier replenishment. The print head also snaps in and out without tools.

Media improvements are most noticeable in direct thermal, with materials that can withstand up to two weeks exposure to direct sunlight. Spot color can also be added to direct thermal with special label stock. For those who want "real" color, there's Astro-Med's Sundance four color thermal transfer printer.

With the right media, thermal printing can produce a very durable image.

Laser Printers

It may be time to rethink assumptions about laser printers as well. Usually favored because they can be used to print reports, inexpensive one-use documents like picking lists, graphics, and bar code labels, high volume laser printers are now coming into their own as label "presses."

Medium-high volume laser printers are available from OTC, IBI, Printronix, and others. The pin-feed mechanism offers particular advantages for very heavy stock. Resolutions of 300, 600 and even 1200 dpi are available, although media considerations still limit most laser printers when printing very high density symbols.

On the high volume end, products like Esselte Meto's LIS-1630 are designed for high-speed, high-volume runs. Particularly interesting with the Meto model is that, rather than proprietary internal electronics, it is controlled by a dedicated PC server, making upgrades and interfacing much easier. Printing up to a 16 inch page at speeds up to 29 pages per minute, at 400 dpi, this is definitely a high-volume machine.

All of these printers are benefiting from improved media, enabling the production of very durable labels. Among the uses of laser printers is the printing of washable care labels for clothing.

Matrix Impact

Those who thought dot matrix was dead have another think coming. Genicom, Printronix, and others continue to prove there's a place for matrix impact printers in the bar code arena.

Although dot resolution for industrial models hasn't improved greatly (still less than 100 dpi), improved hardware, software, media, and ribbon technology are producing higher quality results for medium density symbols. The multi-use nature of matrix, along with wide page width, offers advantages similar to larger laser printers. Matrix printers, however, have other advantages as well, such as the ability to print multi-part forms. In addition, Genicom printers, for example, can feed two separate media at the same time (say, labels and 8.5 inch paper) -- a considerable advantage for mixed-use applications and one that reduces waste.

Windows drivers are also being used to enable printing of TrueType fonts, company logos, and other graphics. High quality matrix impact printing comes with some trade-offs, however. Because the printer makes multiple passes for the same image, print speed decreases when plotting bar codes, graphics, and other high quality items.

Nonetheless, with new ribbon technology and the right media, matrix impact printers can produce good quality, durable bar codes -- or inexpensive one-use picking lists. In other words, matrix impact is still here.

Ink Jet

Industrial ink jet used to be relegated to printing large text or U.P.C. case codes at 20 mils or more (and some of the early examples looked more like a child's connect-the-dots game than a bar code). Recent advances in inks and printhead technology, however, have made ink jet a viable technology for a wide range of direct marking applications. In addition to Interleaved 2-of-5 and Code 128 shipping container symbols, companies such as Videojet and ITI can mark U.P.C. symbols directly onto product packaging. Truncation of U.P.C. symbols is still somewhat problematic but for many hand scanning uses, users are accepting slightly truncated symbols. (Here's where customer standards come into play.)

Ink jet is also poised for new challenges. Domino Amjet, for example, is currently printing high density Data Matrix symbols directly onto production parts.

For all industrial ink jet, durability is dependent on the particular substrate being marked.

Summary

Today's printers offer tremendous flexibility to meet your process needs. Many processes will require the use of different types of printer at different parts of the process. Understanding process requirements can help make the selection process easier.