Type Writing Machine
By about 1910, the mechanical typewriter had reached a somewhat standardized design. There were minor variations from one manufacturer to another, but most type writers followed the concept that each key was attached to a type bar that had the corresponding letter molded, in reverse, into its striking head. To have letters typed in exact location, the type bar was guided all its way till the ribbon by segment. When a key was struck briskly and firmly, the type bar hit a ribbon stretched in front of a cylindrical platen that moved back and forth. The paper was rolled around by the type writers platen, which was then rotated by the carriage return lever into position for each new line of text.