Direct thermal printers work by creating images directly on the printed material without using a ribbon, toner, or ink. This is accomplished by using a chemically treated, heat-sensitive media that blackens when it passes under the thermal printhead.
As a result, this media is more sensitive to light, heat, and abrasion. Labels and tags are not as long-lasting. Images can fade over time, and media will darken if overexposed to heat, light, or other catalysts. We noticed at work that our QR codes were fading because of this.
Thermal transfer printers work by using a heated printhead that applies that heat to a ribbon that has a wax or resin coating, depending on the type of media. The heat from the printhead melts the wax or resin and transfers it from the ribbon and onto the media.
The wax or resin is absorbed by the media so that the image becomes part of the media. This technique provides image quality and durability that is unmatched by other on-demand printing technologies. Thermal transfer printers can accept a wider variety of media than direct thermal models, including paper, polyester, and polypropylene materials.
A thermal printer typically contains at least these components:
- Thermal head: Produces heat to create an image on the paper
- Platen: A rubber roller that moves the paper
- Spring: Applies pressure to hold the paper and printhead together
Thermal printers print more quietly and usually faster than other printers. They are also smaller, lighter, and consume less power, making them ideal for portable and retail applications. Direct thermal printers are generally less expensive, but they produce labels that can become illegible if exposed to heat, direct sunlight, or chemical vapors.