Neither. We used a variety of micros but the majority were based on various Hitachi micros which were selected primarily because of their combination of features and pricing. The very first Dymo electronic label printer made by Dymo (as opposed to badging someone else's design) was the Dymo 4000 which came out around 1987 or so. I was not involved in its design but it used an 8051 variant and a good old HD4480 LCD driver.

I am not sure which model you are refering to. Dymo keep changing their naming system. When we developed them they were known as the 1000,2000, 5000 and so on. I retired 4 years ago from the company that did the developments so if it a relatively new model I cannot throw any light on its design. They were very much designed for maximum functionality from minumum cost hardware whilst being reliable enough to manufacture at a miilion units.

Ian