When choosing a bar code label printer for your business, it's important to remember that not all types of printers are created equal. While dot matrix, ink jet, and laser printers may be capable, at least in theory, of creating scannable bar code labels, in most cases questions about lifetime ownership costs, ease of use, and bar code quality arise. When bar code labels are printed, the tolerances are quite tight, with the width of bars, spaces, and quiet zones measured in thousands of an inch or mils. If bar widths are inconsistent or the contrast between light and dark elements is lacking, the bar code label won't be read.
That's why most companies use thermal printers for their bar code labeling needs. These printers are capable of printing one or a thousand bar code labels at a time, with the highest print sharpness and quality. And since bar code labels are needed wherever products are kept, printers must be able to stand up to harsher conditions than the normal office environment.
(Images, top and right - courtesy of ZebraTechnologies)
What to ask when shopping for a bar code label printer
Finding the right bar code label printer requires an individualized approach. These questions will help you look at your own processes and needs a little more closely.
-What's the expected bar code label print volume?
-Will labels be printed in batches or on-demand?
-What size label will be used?
-How important is print quality? What will happen if bar code label can't be read?
-If label requirements change, can modifications be made internally or will outside support be required?
-How often will bar code label printers need to be replaced or repaired?
-Can the suggested printer stand up to the environment where labels are needed?
-How much ongoing IT support and operator time is needed to run and maintain the system?
Now that you have a better idea what you're looking for in a bar code label printer, consider the two industry standards.
Types of thermal bar code label printers
Depending on the application, a thermal bar code label printer will use either direct thermal or thermal transfer technology to imprint the bar code symbology on the label. Here's a little more information about each type of thermal printer.
Direct thermal bar code label printers
If you've ever left a receipt from a grocery store or a gas station out in the sun and watched the paper turn completely black, then you've observed the results of direct thermal printing. Originally employed with copy and fax machines, direct thermal printing uses chemically coated paper, and is considered very effective for printing bar code labels. The print head consists of a long, linear array of tiny resistive heating elements (100 to 300 per inch), arranged perpendicularly to the direction the paper moves. Each print head element heats the section of the chemically coated paper directly below it. The heat produces a chemical reaction, causing a black dot to form. More and more dots form the complete bar code image.
Thermal transfer bar code label printers
Similar technology is used in thermal transfer printing as direct thermal, but replace the chemically coated paper with non-sensitized label stock and a special, inked ribbon. Coated with dry thermal transfer ink, the polyester ribbon sits between the print head and the label. The heated print head transfers ink to the label surface, where the ink dries and adheres to the label. Once the ribbon is peeled away, the bar code image remains.
Direct thermal v. thermal transfer
Both types of thermal bar code label printers offer advantages and disadvantages during the printing process. In contrast to most laser printers, both direct thermal and thermal transfer printers easily switch between batch and single-label printing without much waste.
Direct thermal printers provide the following benefits:
✓ Easy to use and require no additional supplies like ink, toner, or ribbon.
✓ Sharp bar code print quality that's easily read,
✓ Low long-term maintenance costs and total cost of ownership (TCO).
✓ More durable than dot-matrix or laser printers, meaning that they operate reliably in both industrial and office environments.
The chief drawback of direct thermal bar code label printers is sensitivity to environmental conditions, especially heat and light. The paper also remains chemically active after the printing process is finished, often requiring a top coat that resists UV light exposure, chemicals, and surface abrasions.
Thermal transfer printers offer many of the same benefits as direct thermal technology, including these:
✓ Produces long life image stability
✓ Thermal transfer technology prints on a wide range of media stock.
✓ Very durable, allowing reliable operation in industrial AND office applications.
Supply costs are higher for thermal transfer printers, as they require replacement ribbons. In many cases the ribbons are not recyclable like those of other printer types. And the printer media and the ribbon must be compatible to ensure optimal print quality, otherwise heat from the print head could possible melt the ribbon onto the label, ruining the bar code labels and causing potential internal problems with the printer.
Bar code label printers to consider
Now that you know a little more about what to look for in a thermal bar code label printer, here are some places to start your research.
(1) Zebra Technologies. Zebra offers the widest selection of bar code printers in the industry and supports them extensively with software, connectivity assistance, and supplies. Greater than 90 percent of Fortune 500 companies use Zebra-brand printers. Visit http://www.zebra.com/
(2) Datamax-O'Neil. Headquartered in Orlando, Florida, this global company offers a broad range of industrial bar code printers, and provides stationary and portable label printing solutions, with over 1 million printers manufactured. Visit http://www.datamax-oneil.com/do/com/EN-US/index.cfm
(3) Intermec. Intermec offers industrial label printers for a range of applications, from commercial light volume to rugged, round-the-clock performance. Visit http://www.intermec.com/
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