Types of Bar-code Printers
All bar-code printers are not the same. Some bar-code printers will print labels faster than others, some may have more memory available, and some will support higher densities (dpi). Your specific application will help determine the best type of bar-code printer. Some things to consider are:
- Will you need an industrial or desktop printer?
- How many labels need to be printed?
- Do you require a thermal or direct transfer printer?
- Will you need mobile printing?
- Is your environment dusty or considered hazardous?
- Will the printer connect to a network?
- Do you have security limitations and requirements?
- What size labels need to be printed?
- Do you need to print in color?
- Do you need to print in more than one color?
- Do you require labels in rolls or fan-folded stacks?
- What Density of printer’s print head (dpi) do you need?
- What print speed do you need?
- What interface do you need?
- What software are you using to print your labels?
Questions to Think About:
There are two basic thermal barcode printing methods.
1. Thermal transfer bar-code printing
In this method, the print head transfers ink from a ribbon into standard paper. The thermal transfer barcode printer brings greater consumable costs because it utilizes a ribbon, but there is less wear and tear on the print head. A ribbon produces less friction than paper, so a print head lasts approximately four times longer when printing in thermal transfer mode than in thermal direct mode.
2. Thermal direct barcode printing
In this method, the print head is in direct contact with treated paper, and no ribbon is used. As a result, consumable costs are smaller, but the print head undergoes substantially more wear and tear. There’s a coating on the label media that turns black as heat is applied to it. Because of this, no ribbon is required.
Every thermal barcode label printer is driven by a proprietary programming language, which can make the bar code printing process challenging. However, bar code label software can make it easier by allowing you to create labels on the screen and print barcode labels with data from various sources.
Thermal direct barcode labels will turn yellow over time, and the print will fade to a faint gray. Overnight carriers typically use thermal direct barcode labels because the barcode labels only need to last a day or two. It is reasonable to expect a thermal direct barcode label to last about 6 months. Also, remember that heat is what causes the label to change from white to black. Keep the barcode labels from storefronts, jewelry cases, and lighting centers.
You might think that thermal direct would be a less-expensive method of printing than thermal transfer because you don’t have to buy ribbons. However, thermal direct will wear down the print head faster than with thermal transfer. Paper is coarse and will break the print head down over time. Also, the edge of each label strikes the print head, causing further breakdown. You won’t have to buy ribbons, but you’ll have to buy more print heads, which are expensive. The bottom line is that there is little-to-no difference in the cost of operation between thermal transfer and thermal direct.
Label software can be generic to all printers or specific to one manufacturer. Further, the width of the print head determines the maximum width of printed labels. Print heads are generally 2,4,6 or 8 inches wide.
The quality of the printed barcode label is directly related to the density of the print head. An image appears on a barcode label due to a single dot or series of dots being turned on. The greater the number of dots within an area, the clearer the image. Print heads come in five different densities: 152 dpi, 203 dpi, 300 dpi, 406 dpi, and 600 dpi. TPI can make sure to get the printer that best suits your needs.
Density is measured in dots per inch (dpi). These dots are measured in mils; 1000/1000 mils would make up an inch. Let’s consider a barcode printer with a 203 dpi print head. Divide 1000 by 203 to calculate the width of a dot on a 203 dpi print head printer, which are 4.926 (just round it up to 5) mils. Therefore, if your customer wants to print a 15-mil barcode, a 203-dpi print head would work. Each dot is 5 mils, turn three of them on, and you’ve got 15 mils!
Another example of barcode printing a 15-mil barcode label would be using a 300 dpi print head. Divide 1000 by 300 = 3.333, or just round down to 3. So, if you have a barcode printer with a 300-dpi print head, then 3 mils x 5 = 15 mils.
If labels are being printed using graphics, you would want to get a print head with the greatest density to ensure the reproduction is of good quality.
To print an image, the barcode printer must store a portion, or all, of that label image in its memory before it prints the barcode label. There are different types of memory that serve different purposes. Manufacturers may use different terminology, but as long as you understand what those differences are, then you can apply their terminology to the memory’s function.
SRAM / DRAM: A print head may be the proper density to print a picture on a label, but the barcode printer may not be able to store that entire image up in memory. This is where SRAM or DRAM comes into play. This gives the barcode printer the ability to allow the printer to print a longer label, as well as store that large image in memory. Any data stored in SRAM or DRAM will be lost when the power to the barcode printer is turned off. Flash: “Flash is like a floppy.” If the printer has to wait for the host to send an entire image down every time it wants to print it, the printing is going to be very slow. Having Flash memory will allow you to store the image on the printer, which will greatly speed up the printing of the label. It’s like a floppy diskette because it is permanent storage and does not require power for the data to be maintained.
Labels and ribbons come in different varieties. Labels can be paper, polyester, polyolefin, or polypropylene, to name just a few. Ribbons can be wax, a mix of wax and resin, or resin.
Barcode Printer Interfaces
Connecting printers to a computer or network can be accomplished in several ways. When making your barcode printer decision, you will need to ensure the printer selected supports the connectivity methods desired. Most barcode printers today will by default include a serial, USB, and parallel port unless using a network connection. For example, if connecting to an Ethernet network, you would naturally have an Ethernet port, but the barcode printer may also have a USB port as well.
Bottom Line: TPI will analyze your needs and select the best barcode printer for your application.