How to Avoid Smeared Thermal Transfer Printing

By George Righter

A friend of mine who knows how much I like to analyze labels and print jobs recently showed me some cannabis containers with smeared printing. Since this is considered medical packaging, the printing needs to be legible and durable. In this case, the black thermal transfer print is neither. I contacted the company via email and said I could easily and quickly solve the problem but haven’t heard back. I’m interested to see if the same issue occurs down the road, as this is a safety issue.

First a little information about the labels. These labels are made from a polypropylene film which repels moisture and works the best on curved surfaces. There is a tamper evident perforation where the lid meets the container that indicates the container has been opened. The labels look to have been pre-printed on a flexographic press. They most likely order the pre-printed labels in bulk for cost savings.

Next the pre-printed labels are loaded onto a thermal transfer printer, which will imprint variable information (ingredients, percentages, dates and tracking numbers can change among lots) with a black thermal transfer ribbon. The ribbon needs to be matched with the label material for durability and overall print quality. In this case, a wax ribbon was used rather than a more durable wax/resin, or pure resin ribbon formulation. The simple remedy here is to go with a more durable wax/resin ribbon.

So how did this occur? Who dropped the ball? Here are some ideas:

  •  The label ribbon combination was never tested and there is no specification
  •  Incorrect ribbons (wax grade) were ordered
  •  Correct ribbons were ordered (wax/resin) but the ribbon vendor shipped wax instead
  •  The ribbon supplier shipped the correct ribbons, but they have a quality issue
  •  The ribbon supplier or customer could only procure wax ribbons

In any event, to consistently print durable legible labels, the thermal transfer ribbons should first be tested and matched properly on the label material and made part of the label/ribbon specification. Then when the ribbons arrive, a print durability/scratch smear test should be able to validate the correct ribbons were ordered and received.

Rightertrack provides guidance for mission critical label printing. We’ll match your label material with a proper thermal transfer ribbon combination. We have decades of experience. Get it right the first time and avoid headaches by contacting George Righter at 215-493-7191 or email