Heater for processing thermally sensitive paper - has electrodes providing HF field parallel to sliding plane of paper

摘要

The heater is powered from the dielectric loss of a material at a h.f. This is used to process isolating material in sheet form and allows the system to be used for reproduction of information received from a transmission line on a paper coated with thermosensitive material. The electrodes (10, 11) of the heater provide an HF electrical field whose lines of force are parallel to the sliding plane of a sheet (12) of material being processed. The electrodes are mounted in grooves in a bar of isolating material through which the sheet passes. A supplementary conductor (18) is used when a very high operating frequency is employed. The electrodes are driven from an oscillator (19) which drives a power stage comprising a transistor (21) through a low value capacitor (20). The electrodes are connected to a step up auto transformer (24) in the collector circuit.