Tech Specs: Barcode Printers

The Right Size: Desktops, Midrange, Industrial, High Performance, Wide Width

Convenient classifications for barcode printers is by size, which is usually the size of the "footprint," (the space the printer takes up just sitting there), or by performance, (the speed at which they print, or the types of labels they can print, or the print resolution). Here are some of the general classifications based on size and performance:

Desktops - Usually desktop printers are used for smaller labels, or for low volume printing jobs. Typically, they have capacity for smaller rolls of labels, (fanfold labels can also be used), with 1-inch cores and 4-inch outer diameters. Adapters can be purchased to allow for larger rolls to be used.
Midrange - Midrange printers take up a little more space, and depending on the printer model, may take either larger or smaller rolls. (As always, fanfold labels can be used, in which case roll size doesn't matter!) Print speeds and print resolution may be a little higher than desktop models, as well.
Industrial - Industrial printers are built with stronger cases to take the punishment of an industrial work setting, and are generally built to print higher volumes. They typically hold larger capacity rolls of labels in internal bays. Industrial printers may have more on-board memory, to allow for advanced printing functions/operations.
High Performance - High performance printers usually are distinguished by very high print speeds, or the capacity to handle high-volume rolls, or switch between multiple label designs with on-board memory or programming. High performance printers may have attachments that allow automated application of printed labels to cartons or packages at very high speeds.
Wide Width - Wide width printers are distinguished by their capacity to handle labels wider than 6 inches. Such labels are used for chemical drums, large shipping labels, and other applications where a larger-than-normal label is required.

Printing with Heat

Barcode printers use printheads that generate heat to print labels. There are two main types of printing: Thermal Transfer and Direct Thermal. Some - but not all! - barcode printers can function as either Thermal Transfer or Direct Thermal printers.

Thermal Transfer - The printhead heats and melts a wax, resin or wax/resin composite ribbon material onto the label, forming the image. In Thermal Transfer printing, a ribbon is required.
Direct Thermal - In Direct Thermal printing, the printhead heat causes specially treated paper to react and form the desired image. No ribbon is required, but you do need specailly treated paper or synthetic labels. In addition, Direct Thermal labels tend to be heat-sensitive, and darken or fade after about 6 months. (Think of some grocery store receipts that darken and fade after a while sitting in your hot car - and you'll know the problem with direct thermal!)

Print Speed

Print speed on barcode printers is measured in Inches Per Second (abbreviated "ips"). If you print a small number of labels at a time, and have no need for high-volumes of labels, you probably won't be too concerned with print speed. But for high volume printing, or where printing speed matches the speed of an assembly line, print speed is a very important consideration. If a printer has a print speed of 6 ips, and you have labels that are 6 inches long, you'll be able to print one label per second. If your labels are 3 inches long, at 6 ips you can print two labels per second, and so forth.

Print Width

Barcode printers usually have a maximum print width, expressed in inches. This is the maximum width a label can be, but typically printers can handle labels that are any size less than the maximum print width. If, for example, you printer has a print width of 4.2 inches, you should be able to use a 3-inch wide label with no problems.

Print Resolution

Print resolution is measured in Dots Per Inch, (abbreviated "dpi"). The higher the dpi, the better the image, and the clearer and crisper the barcode will be. Higher print resolution helps produce a sharp, clear image, where the comparative width of the bars holds the data. Sharply printed barcodes mean fewer scanning errors. Keep in mind, that to properly scan, a barcode must be printed at a resolution that allows your reader to properly scan it, and at an optimum distance. This involves proportionality of height and width of the printed barcode and the "density." For example, if you print a 30-character barcode on a 1-inch square label, and expect it to be read from 12 feet away, the scanner is going to have trouble reading the printed barcode. Plan your labels accordingly!

Interfaces

Parallel - Parallel data transmission employs up to 8 separate wires (depending on whether a parity bit is used) to transmit each of the 8 bits that make up 1 byte of data. Parallel mode offers increased transmission speeds, compared to RS-232 Serial, as well as unambiguous bit location.
Serial - Serial interfacing requires only a single line to transmit data and is therefore theoretically better for long distance transmissions. Since only one transmit or receive line is used, the maximum data transfer rate is not as high as parallel data transmission. This data transmission protocol used is known as RS-232 Serial. The maximum RS-232 serial cable length for reliable data transmission in a common hardware configuration is approximately 16 meters (50 feet), unless a line repeater is used.
USB - The Universal Serial Bus (USB) uses advanced serial data interfaces at much higher speeds than conventional RS-232 serial with advanced power management (using built-in power lines).
Other Interfaces - Twinax is a type of cable similar to coax, but with two inner conductors instead of one. It is used in IBM midrange (AS/400, System/3x) communications environments.
Coax is a high-capacity cable used in communications and video, commonly called "co-ax." It contains an insulated solid or stranded wire surrounded by a solid or braided metallic shield, wrapped in a plastic cover. Fire-safe teflon coating is optional.

Drivers

Also called a "device driver," it is a program routine that links the operating system to a peripheral device. Written by programmers who understand the hardware's command language and characteristics, the driver contains the precise machine language necessary to perform the functions requested by the application.

When a new hardware device is added to the computer, such as a display adapter, its driver must be installed in order to use it. The operating system calls the driver, and the driver "drives" the device. Routines that perform internal functions, such as memory managers and disk caches, are also called drivers.

Typically, drivers are written by software developers for each printer to work with a specific software application. For example, Seagull Scientific's software developers will write drivers for specific printers to work with BarTender, the company's label design and printing application.

A Note About Ribbons

Some printers are designed to only work with ribbons manufactured by that printer company. So-called "third party" ribbons may not work on all printers, and companies who purchase printers may be unable to procure lower cost "third party" ribbons to realize cost savings in "consumables." Be sure you know exactly the type of ribbons the printer you choose will utilize, and any alternatives you may have for using third-party products.

Click here to read more about Barcode Ribbons.