Importance

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Abstract

In an electronic typewriter having a printing device of the daisywheel type, the direct current electric motors which control the rotation of the character-carrying element, the movement of the carriage along the various printing positions and the rotation of the platen roller for line spacing are associated with corresponding transducers which detect the angular position thereof, and are actuated by a single integrated circuit connected to a microprocessor by an address and data bus (43). The microprocessor determines, for each of the motors, the angular amplitude of the rotary movement and the time required to cover each of the elementary angular distances, in accordance with a given speed law and addresses with data, including the said time, a plurality of circuit modules (B1, B2, B3) individual to the motors. The modules issue motor command signals (e.g. M11, M21, M31). Checking as between the actual speed and the desired or theoretical speed is effected by the modules of the integrated circuit using the timing signals (e.g. STA 1, STB 1) generated by the transducers connected to the motors. The modules send back interrupt signals (INT 1, INT 2, INT 3) which provide interrupt vectors (46) for the microprocessor, enabling the microprocessor to determine the new data to be sent to the modules.

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First Claim