Thomas Edison's US Patent (No. 224,665) for a method of preparing autographic stencils for printing.
In 1885 Thomas Edison, who had invented the Electric Pen in 1876, agreed to sell his patents for this device to Albert Blake Dick, who had invented the mimeograph stencil. Edison also agreed to help Dick market the mimeograph under the name, Edison Mimeograph. Marketed by the AB Dick company of Chicago, the mimeograph became the first widely used duplicating machine.