Special symbol generator for high speed printer

Claim 1

In a high-speed dot matrix printer of the kind comprising a plurality of individual signal-actuated dot printer elements that print standard data characters in a basic format constituting a group of dot-position columns each including a given number of dot positions, with each such group of columns normally separated from the next adjacent group by a predetermined number of blank columns, a control system enabling the printer to print special symbols unsuited to the basic format, utilizing an input signal comprising a series of intermixed code words individually respresentative of standard data characters and special symbols, said control system comprising: a plural-level data store for receiving said input signal and capable of storing a plurality of received code words, each received code word being initially recorded in an input level of said store and then advanced to an output level; a main character signal generator, coupled to said dot printer elements, for actuating said dot printer elements to print characters in said basic format; encoding means for generating a series of modified code words each representative of a part of a special symbol, which part is reproducible in said basic format; an auxiliary character signal generator, coupled to said dot printer elements, for actuating said dot printer elements to print dots in a predetermined pattern in one or more columns adjacent the columns of said basic format to complete the reproduction of said special symbols; gating means, coupling an output level of said data store and said encoding means to said main character signal generator; and special symbol detector means, coupled to said data store, said gating means, and said encoding means, for identifying received code words representative of said special symbols, and for actuating said gating means and said encoding means to apply modified code words to said main character generator; said encoding means also being coupled to said auxiliary character generator to actuate said auxiliary character signal generator.