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Media Selection
The following is a limited overview of media characteristics. For complete information and
advice regarding your specific application needs, always consult a qualified media specialist
or a Datamax Media Representative.
Media Selection – Direct Thermal
Consider three important factors when selecting direct thermal stock:
> The abrasive qualities of the material that covers the thermal reactive layer of the paper.
> The ability of that layer to control the chemical reaction that occurs when the image is “burned”.
> The amount of heat required to create an image on the paper.
Print Quality Controls
The printer provides flexibility with a comprehensive set of print controls. Of these, the
amount of heat applied by the printhead and the rate of media movement will have the most
effect on the printed images. Low cost direct thermal stocks, for example, have raised
reaction temperatures and therefore require higher heat values and slower print speeds to
make a clear image on the media. In general, there are two standard methods to control print
quality:
> The first method is to change the ‘Print Control / Heat’ setting (also selectable as ‘Heat Setting’ in
most labeling software programs). Increasing this value causes more energy to be transferred to the
media, resulting in a darker image. Conversely, if the image is too dark, reduce this value.
> The second method is to change the ‘Print Control / Print Speed’ setting (also selectable as ‘Print
Speed’ in most software programs). Changing the print speed changes the amount of time the
media is under the printhead. Slower speeds allow more time and control for energy transfer, while
faster speeds will increase throughput, but may require higher heat settings.
You will find that printing barcodes and detailed images on less expensive direct thermal
media at higher speeds can be tricky. At one heat setting, the images will fade and at the
next higher heat setting, the images will bleed. This is because the reaction temperature of
the media is so high that at higher rates of speed, it cannot react fast enough. To print fine
images at higher speed, media with lower reaction or release temperatures are required. On
the slower end of the print rate settings, crisper images are possible because the media is not
being stretched beyond its limits.
For specific application information, consult your media specialist or a Datamax Media
Representative. Or download our "A Brief Introduction to Media" whitepaper at
www.datamaxcorp.com
