Overhead projector with facility to produce hard copy from sketches made on foil

摘要

The overhead projector has a facility to sketch diagrams and write text onto a transparent foil (3) that is passed between a pair of rollers (2). Located directly beneath the foil is a load cell (5) that responds to the force applied by the pen and the signals produced are digitised and stored in memory . The data is processed before outputting to a copier.