Method for controlling the flight time of a print hammer in an impact printer and impact printer embodying the method

摘要

In an impact printer including a print wheel having a plurality of selectable character type bearing elements for respectively printing a plurality of characters, said print wheel being rotatable for selectively positioning selected type elements in successive print positions, impact means impellable against the selected elements to drive said elements against the printing medium and means for impelling the impact means against said selected type element, the present invention provides the improvement comprising the combination of means (20, 24) for sensing the flight time of the impelled impact means until impact by sensing variations in the velocity of said impact means, means (25) for comparing the sensed flight time to a predetermined desired flight and means (27) for selectively varying the amplitude of the current to the impelling means (23) to adjust the sensed flight time to equal the desired flight time.