Monday, July 24, 2017

What is the difference between thermal direct and thermal transfer label printing?

What is the Difference Between Thermal Direct and Thermal Transfer Label Printing?

I had a few questions on this recently so thought it would be a good topic to cover here. The main differences between the two processes is the label material that is being used. Many label printers being sold will work with both direct and transfer materials, you just need to select and purchase the correct materials to best match your application and make sure you select the matching option in the printer driver setting when you print.



Thermal direct label stock has a chemical coating on its surface that changes its color when heated (normally to black, but colors are available at a premium). The heat is created by a row of very small resistors at the front of the printers print head. 

A thermal transfer label looks the same as a thermal direct label, but to put an image on it, you must use a special ribbon (these come in many colors including gold and silver).

The ribbon and the label material travel under the print head at the same time and are heated in the same way that the direct material was heated. However, in this process material from the ribbon is transferred to the surface of the label, which generates the image.








How to tell what label roll you have?

If you have a roll of labels and you are not sure if it is a thermal direct or thermal transfer label there is a simple way to test. Quickly scratch your nail over the surface of the label (put the label on a flat hard surface and run your nail over it quickly when applying pressure). If the label is a thermal direct, this action will heat the material enough to leave a black mark. If you do this and there is no mark, then it is more than likely to be a thermal transfer label.

Applications for thermal transfer and thermal direct labels

If your application requires that the label only needs to last a short time and it is not used in a very hot environment, then a thermal direct label is usually ideal. It is important to note that this type of label is susceptible to fading if left out in the sun, and will change color if heated. Both heat and the sun will leave the label unreadable. 
Thermal direct labels are often used for shipping labels or receipts. They are also used on products that have a short shelf life like sandwiches. Many retail application use thermal direct materials as they only require staff to replace one consumable, which is simpler.

If your application requires the label to be readable for a longer period of time (months or years), or will be left in the sun, or even in a hot environment then it is better to use thermal transfer. The best match for asset tracking, warehouse location, and UL labels would be thermal transfer.

It is also important to note that thermal transfer works with several types of ribbons – wax, wax resin, and resin. The ribbon used depends on the label material to be printed, and/or the environment that the label has to withstand. Wax is more a general purpose, cheaper material that makes a great image, but can be scratched off. If you need to print on a polymer material or the label has to withstand harsh environments, then a resin ribbon is the better way to go.'
Zebra ZD500 runs in direct thermal or thermal transfer mode.

Other things to remember when talking about labels

Zebra ZT410 runs in direct thermal
or thermal transfer mode.
  • What is the ideal external diameter of the label roll for your printer? – each label printer is designed to hold a maximum label roll diameter and will not work with larger rolls
  • What is the ideal external diameter of the label roll core? – most large printers are designed to handle a roll core of three inches, but smaller printers have different sized cores, so check what core diameter your printer needs
  • How are your labels wound onto the core? – the labels can be wound inside (with the face of the label pointing into the center of the roll) or outside wound (the face of the label pointing away from the core). Again, it is important to know which wind your printer works with for optimum operation.
  • What label roll width is supported by your printer? – Each printer will work well with labels of a certain size (min size and max size). If you try to operate the printer with wider or narrower labels will cause issues.
  • Are you running the printer with the ideal ribbon width for your label? – though not every width of label is supported by ribbon widths, and it is also impractical to stock every width of ribbon, it is best to use a ribbon that matches your label width. Using a ribbon that is much wider than you label can cause print problems, like ribbon wrinkle and of course wastes ribbon that you are not using to print on. 
Zebra 110xi4 runs in direct thermal or thermal transfer mode.
This blog is written as a rough guide and we recommend researching the product you need in more detail before making a purchasing decision. We hope that it is helpful and if you have any questions on anything in the blog or want more information please feel free to call the RedLine Solutions team at 408-562-1700 or email us at sales@redlinesolutions.com.

© RedLine Solutions Inc. 2017. Unauthorized use and/or duplication of this material without express and written permission from this site’s owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to RedLine Solutions and there is the inclusion of a link to www.barcodenerd.com. Printer images provided by Zebra Technologies.

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