People are often confused about the distinctions between direct thermal printers and label printers for thermal transfer, and which type best fits their requirements. Here is all you need to know about these two printing methods.

Firstly, each technique utilizes a thermal print head that applies heat to the marked surface.

Thermal transfer printing requires a heated ribbon to create long-lasting, durable images on a broad range of materials.

In Direct thermal printing no ribbon is used, which generates the image directly on the printed material. Direct thermal media is more sensitive to light, heat, and abrasion, reducing printed material’s life.

The best technology for printing barcodes

For barcode label printing, thermal label printers are perfect because they generate precise, high-quality pictures with great edge definition. Thermal printers are designed for printing within tight tolerances and for producing the precise bar widths required by effective barcode printing and scanning. Each technology, at the same print resolutions and speeds, can produce one- and two-dimensional barcode symbologies, graphics and text.

Choose according to your application needs

Here is all described to help you know the technology differences and how to select the right print method for your application.

1. Direct thermal printing
   ● Utilizes heat-sensitive chemically treated media that blackens when passing under the heated print head. There is no ink, toner or ribbon in direct thermal printers.
   ● Simple design makes it durable and easy to use thermal printers.
   ● Because there is no ribbon, it costs less to run direct thermal printers than printers of inkjet, laser, impact and thermal transfer.
   ● Pictures of thermal media may fade over time. If the label is overexposed to heat, light, or other catalysts, the material becomes dark and the text or barcode becomes unreadable. For these purposes, direct thermal printing is not used for lifetime identification apps.
2. For Thermal Printing
   ● In thermal transfer printing, a thermal print head applies heat to a ribbon that melts ink to the image forming material. This technique gives unparalleled picture quality and durability as compared to other on-demand printing technologies.
   ● Thermal transfer printers can accept a wider range of media than direct thermal models, including paper, polyester, and polypropylene materials.

Design and working

Key components of direct thermal printing

• Thermal head: produces heat; prints on paper.
• Platen: a rubber roller that feeds paper.
• Spring: applies pressure to the thermal head, which causes to contact the thermo sensitive paper.

Thermo-sensitive paper is inserted between the thermal head and the platen for printing. The printer sends an electrical current to the thermal head heating elements generating heat. The heat activates the thermo sensitive paper colour layer, which changes colour when heated. Such a mechanism of printing is known as a direct or thermal system.

Key components of thermal transfer printing

• Non-movable print head
• Carbon ribbon (ink)
• Printable substrates (typically paper, synthetic, card etc.)

Thermal transfer printing is performed by melting wax in a specialized printer’s print heads. These three components actually form a sandwich in the middle with the ribbon. A thermally compliant print head, combined with the ribbon’s electrical properties and the correct rheological properties of the ribbon ink, is all essential in creating a high-quality printed image.

There are choices available for print heads in 203 dpi, 300 dpi and 600 dpi resolution. Each dot is addressed independently, and when a dot is addressed electronically it heats up to a pre-set temperature (adjustable). The heated component fuses the wax or resin-based ink instantly on the side of the ribbon film facing the substrate and this process is immediately transferred to the substratum in combination with the constant pressure applied by the print-head locking mechanism.

When a dot “turns off”, that print head component cools down instantly, and that portion of the ribbon stops melting / printing. It is completely dry as the substratum comes out of the printer and can be used immediately. Carbon ribbons are on rolls and are fitted onto a spindle or reel holder within the printer.

Conclusion:

While both printing techniques are up to the mark, everything depends on what type of business you own and what your demands for label printing are. If you own a small business that doesn’t need long-life labels then a direct thermal printer is your best choice. If your business is large and your products require labels capable of withstanding harsh conditions, a thermal transfer is your best choice. It all depends upon your business requirements!

ADC Barcode is involved in the supply of  barcode scanners, barcode label printers, barcode verifiers and label applicators. We also provide custom software, EPOS systems & hardware, RFID and wireless networking technology amongst other professional services. Get in touch now and obtain more information.