Thermal printing uses one of two processes: thermal transfer or direct thermal printing. Both methods are similar in that they both use thermal print heads to apply heat to the surface. However, direct thermal printing requires chemically treated heat-sensitive materials, while thermal transfer printing uses a heated ribbon to transfer the image to various materials.
In both methods, a printhead containing a small heating element delivers heat to a specific area to produce an image. In both methods, the resolution of the image is determined by the arrangement and number of heating elements, or dots per inch (DPI). The higher the DPI, the better the print resolution and quality. The main difference between the two methods is the printing surface, which we will detail further below.
Thermal transfer
To choose the best thermal printing technology for a given application, it is necessary to have a basic understanding of the capabilities of each method. Let’s take a closer look at how thermal transfer printing works and its unique advantages.
How does a thermal transfer printer work?
Thermal transfer printing uses a heating element located in the print head to deliver a well-timed amount of heat to the passing ribbon. The ribbon melts onto the label, forming the printed image. The label absorbs ink to apply the image to the media. In this type of thermal printing, the ribbon and label stock must be chosen carefully. The materials and bonding qualities of labels and ribbons must be well matched to achieve the highest quality and durability of printing. Choosing the right materials allows the final product to withstand chemical and UV exposure, extreme temperatures, rigorous cleaning procedures, and more.
Advantages of thermal transfer printing
Thermal transfer printing enables crisp, high-definition images, text and graphics with maximum readability, scannability and long-life image stability. Single and batch printing can be performed with virtually no waste and can be printed on virtually any media. Thermal transfer printers are more durable than traditional printers, providing greater reliability and lower maintenance costs for your application.
Thermal transfer printing applications
Thermal transfer printing is compatible with an almost infinite variety of media, making the applications of this printing method equally diverse and suitable for many industries. Some common applications include:
Circuit board tracing
Asset tag
Inventory identification
cold storage
Outdoor application
Certification label
Label laboratory specimens
direct thermal printing
In direct thermal printing, the image is applied directly to the material rather than using a ribbon as in thermal transfer printing. The following sections explain how direct thermal printing works, its main advantages and its most suitable applications.
How does thermal printing work?
In this technology, a heating element in the print head applies heat directly to a label with a heat-sensitive coating. Chemicals in this coating cause a reaction that changes the color of the label from white to black in the heated area. Direct thermal printers are simpler in design than thermal transfer printers because they do not require ribbons.
Advantages of thermal printing
This method produces images that scan well and can be used with recyclable materials. This method is ideal for applications where the image does not need to last long, such as receipts or shipping labels. Thermal printers use no ink or toner, making them easy to operate. They produce virtually no waste and have low long-term maintenance costs because they are very durable and have no supplies that need to be replenished.
Thermal printing applications
Thermal transfer printing vs. direct thermal printing
Labels used in direct thermal printing are extremely sensitive to heat, light and other environmental conditions. Therefore, common applications include items typically used or stored indoors, such as:
Receipt
Tickets
Visitor identification for hospitals or schools
shipping label
pharmacy labels
food labels
restaurant order tags
barcode
