GB1411549A - Automatic typewriters - Google Patents

Abstract

1411549 Automatic typewriters DATAPLEX Ltd 18 Dec 1972 [1 Oct 1971] 45833/71 Heading G4H In an automatic typewriter the actuation of the type bars corresponding to any two successive characters to be printed is arranged to occur an interval of time a part which depends on their spatial separation in the type basket. Characters in an 8-bit code are input to a buffer store 16 from, e.g. a keyboard, a computer, a magnetic card or punched tape, each character in turn being transferred to an 8-bit shift register 20. The character in 20 is fed to a coding translator 24, then back to 20: it is now in the form of a 6-bit code indicating the sequential position of the type bar in the type basket plus an upper/lower case bit and a parity bit. This character is input to a further register 30 whence it is transferred to a decoder 12 and a control circuit 40 so that the type bar may be actuated; a sensor 14 provides a feedback signal to 40 when the type bar passes through a predetermined position. The output from 30 (representing the character currently being printed) and the next input thereto (the next character to be printed) are fed to a subtractor 34 which calculates the modulus of the difference in positions of the two type bars; if this is greater than three then the next type bar is actuated immediately upon receipt of the signal from 14, but if it is three or less then actuation is delayed so as to avoid interference between closely situated type bars. It is stated that this arrangement (distinguishing only between more than three and three or less) is the optimum one for obtaining increased speed of operation.