Enhanced underscoring methods and means for automatic typewriter and the like employing hammer-type impact printing mechanism

In an automatic typewriter including a keyboard having a plurality of keys representing different underscoreable characters and other keys representing non-underscoreable commands, means for converting strokes of said underscoreable character keys into corresponding data words of predetermined bit length and for converting strokes of said non-underscoreable command keys into command signals having a form distinguishable from said data words, a platen for supporting a copy carrier, a printing mechanism for serially printing successive characters on said copy carrier, and drive means for moving said printing mechanism transversely of said platen;

• the improvement comprising a controller including
• buffer storage means for storing data words and command signals generated in response to said key strokes,
• means for entering an underscore command into said controller,
• means for scanning said stored data words and said command signals in response to said underscore command to alter all consecutive data words preceding said underscore command without interruption by a command signal to indicate that the characters corresponding to the altered data words are to be underscored,
• and an escapement control means responsive to the altered data words for repositioning said printing mechanism after the characters to be underscored have been printed with at least a predetermined per character advance and for then incrementally advancing the printing mechanism at a less than said predetermined advance per character rate of advance to print underscoring characters in overlapping relationship.

A method for printing a substantially straight underscoring line on a platen supported copy carrier through the use of a hammertype impact printing mechanism having a hammer, an inked ribbon, and a character wheel positioned between said hammer and said ribbon to carry a plurality of different characters, including an underscore character;

• said method comprising the steps of
• advancing said printing mechanism for the printing of each of said characters, except for said underscore character, a distance sufficient to print said characters in spaced apart relationship;
• and
• limiting the per character advance of said printing mechanism, while printing said underscoring line, to an increment shorter than said distance and shorter than a predetermined underscore character width, whereby adjacent underscore characters are printed in overlapping relationship.