Difference between the Zebra GK420D and the GK420T?

The “D” behind the Zebra GK420D stands for Direct Thermal. This means that printing occurs through heating of the print head on the part you want to have printed. The top layer of the thermal label responds to the heat of the print head. For example, when you scratch on the label with your nails you’ll see a discolouration. Here you can see that the label is a thermal label. Direct thermal printing is a simple solution for labels that are needed for short-term and is often used for shipping / mailing labels. These label printers are cheaper to purchase and the use of an ink ribbon is not necessary and not possible.

The “T” behind Zebra GK420T stands for Thermal Transfer. In contrast to the D-model, the T-model uses an ink ribbon to print your label. These print labels don’t respond to heat. It works like this. When using a printer with a ribbon, the ribbon is between the print head and the label. The print head printer gets heated, just like the D-printer, and it heats the parts of the ribbon that need to get printed on the label. These parts will stay visible on the label.