Differential key lock mechanism for justifying text writing composing machine

摘要

A desk top justifying text writing composing machine including automatic encoding and reading control means for operating a desk top justifying reproducing machine, or for operating larger and more sophisticated printing machines capable of automatic justification. The machine will produce unjustified typed lines and will automatically encode for controlling another machine to print justified lines, as a result of a single series of manual keyboard composing operations and automatic code controlled reproducing operations for producing a justified copy of a literal text, respectively. A differential character and space key lock means prevents operation of character and space keys that would extend a line beyond the right hand margin, and this means is appropriately effective to permit the addition of any character or space that will still fit in the line at any given time. The arrangement also accounts for the difference in character sizes for each key in upper and lower case conditions.