Thomas Edison of the Edison patent to charge a more reasonable rate for the use of the Edison patent rights and lowering the price of the electric lamp. On October 8, 1883, the US patent office ruled that Edison's patent was based on the work of William E. Sawyer and was, therefore, invalid. Litigation continued for nearly six years, until October 6, 1889, when a judge ruled that Edison's electric light improvement claim for "a filament of carbon of high resistance" was valid. To avoid a possible court battle with Joseph Swan, whose British patent had been awarded a year before Edison's,
Electric pen Electric pen Thomas Edison's electric pen, part of a complete outfit for duplicating handwritten documents and drawings, was the first relatively safe electric-motor-driven office appliance produced and sold in the United States. Edison recognized the possible demand for a high speed copying device after observing the incredible amount of document duplication required of merchants, lawyers, insurance companies, and those of similar occupations. To satisfy this demand, Edison invented the electric pen, which uses a perforating function inspired by the printing telegraph. Edison and his associate Charles Batchelor observed that as this device punctured the paper, a mark was left underneath