In the 1980s the Alps 4-pen printer/plotter mechanism was used by almost every home computer manufacturer, for portable computer printers as well as a number of pieces of medical equipment. While they were not fast, they were compact, and did allow for 4 color printing/plotting at an affordable price.   Over the years they all develop the same problem however, the pinion gears on the stepper motors crack. Plastic shrinks over time and a small plastic gear pressed onto a steel shaft wil