Did you ever wonder exactly what that dark line is at the top of a thermal printhead?
It’s a question Gulton engineers get all the time and it has a simple answer.
It is the heater line.
It’s actually what allows a thermal printer to print. The heater is broken into hundreds of dot segments, usually 200 or 300 dots per inch. Each heater segment can be activated separately, on or off, hundreds of times per second. The paper, or label or transfer wax, media moves under the printhead heater line. The media is activated to change color by heat under each tiny dot heat source in less than a 200th of a second.
The result with hundreds of individual heater dots is a rastered 2 dimensional pattern of thousands of dots per second. Each dot, either printing dark or light depending if the heater segment if hot or cold, prints at several inches per second, in some cases over 10 inches per second.
That one thin line on top of your printhead is a powerhouse of thermal printing.
Needless to say, the line gets incredibly hot while it’s doing its job so it isn’t advisable to touch the ceramic surface during or immediately after printing. In addition, this heater lines needs to be kept clean. Any dirt which collects on or near it this line will affect the print pattern. Sometimes, one or more of the heater dots can fail. Often this can be to poor cleaning, mechanical mishandling which scratches the heater area, or simple the end of life of the printhead. The best way you can ensure maximum printhead life is to pay close attention to proper care and cleaning. We’ll address that in our next issue, so stay tuned.