What is Thermal Transfer Barcode Printing?

By Tim Walker

Thermal Transfer

• Uses a ribbon to transfer ink to label
• Crisper printing (important for barcode compliance)
• Long life span for printed labels
• Wide range of media material types
• Ribbon protects printhead, prolonging its usage
• Used when label is needed for longer period of time
• Used when label is required to be exposed to harsh environments

Thermal Transfer works by having the printhead heat an ink ribbon. The ink is actually melted and transferred onto the label where it quickly solidifies forming the desired image. Notice in the video you can see where the ink has been transferred from the ribbon to the label. Since the ink is actually bonded to the label, Thermal Transfer has the advantage of creating a more permanent image on the label. The images also tend to be crisper, making it good for high definition text and barcodes. Thermal Transfer is used in applications where the label needs to have a longer lifespan than Direct Thermal can provide or has to exist in an environment, like direct sunlight, that would cause problems for Direct Thermal. The ribbon also contains a coating on the back that helps protect the printhead, extending the lifespan of the printhead.

The disadvantage of Thermal Transfer is the actual ribbon itself. There is the additional expense of the ribbon, the additional cost in time involved when changing the ribbon, and the hassle of disposing of the used ribbon.

Thermal Transfer is used for applications where the tag is expected to have a long life span, or exist in a difficult environment. There are also more options for types of media when using Thermal Transfer, opening up applications that are not available to Direct Thermal. Some common examples would be permanent shelf tags, asset tags, labels on vehicles and boats, wrist bands, plant tags, and the list goes on.

As thermal transfer labels move past the printhead, the printhead will heat up to a specific temperature to cause the ink on the ribbon to separate from the backing and affix to the label which in turn produces the desired image/text on the media. Shown above is an example of thermal transfer printing. As the label was feed from the left side of the graphic to the right side, the printhead heated which caused the ink to bond to the media to make that specific spot black and cooled where no ink transfer was needed. This produces the desired output on the label.

Advantages of Thermal Transfer

• Suitable for permanent labeling solutions
• Crisp printout
• Ribbons protect the printhead
• Not subject to label degradation in adverse eviroments

Since the transferred image is bonded to the media, Thermal Transfer labels are more suitable for permanent/long life labeling solutions.

Printout is crisper than direct thermal – ideal for barcodes or higher quality text.

Ribbons (in contrast with direct thermal labels) are like a buffer for the printhead. They have special coatings on their back to protect the printhead from the abrasive direct contact of the media.

Since the labels have transferred images and not a chemical reaction to create the image, the labels are not affected by adverse temperatures – great for archival quality and/or in non-temperature controlled environments such as warehouses.

Disadvantages of Thermal Transfer

• Ribbon costs
• Downtime due to ribbon replacement
• Disposal of spent ribbons

Just as the ribbon is an advantage, it is also a disadvantage because it adds cost to the total solution, downtime during replacement, and costs associated with the disposal.