A printer comprising a typewheel, typebar and position determining device. The typewheel is made with raised characters on its periphery and rotates at constant speed. The typebar is rockably supported on a shaft and has a portion for striking a selected character through paper, etc. in its printing position. The position determining device is associated with the typebar to swing it from the rest position to the driving position. The typebar in its driving position is impulsively rocked by engaging a hammer rotating in synchronism with the typewheel, and then returns to its rest position. The typebar in its rest position engages the position determining device without rocking so as to prevent double or repeated printing.
