Abstract: A teleprinter includes a carriage for conveying a dot matrix-type print head along an operating path parallel to a print-receiving surface. The carriage is mounted on parallel-spaced support rods by means of spaced bearings slidably engaged to one of the support rods, and a pair of perpendicularly-aligned guide rollers which engage the other guide rod. The carriage is advanced by a drive belt which extends along the carriage operating path and is attached to the carriage at either end. A stepper motor coupled to one of the pulleys drives the belt to position the carriage. A removable cartridge on the carriage contains an inked ribbon which is advanced with movement of the carriage by a drive gear engaged to the drive belt. A unidirectional clutch prevents the inked ribbon from moving in a reverse direction during carriage return.

Abstract: A dot matrix-type print head for forming a character-defining array of individual dots on a print-receiving surface includes a plurality of parallel-spaced print wires arranged in a vertical plane perpendicular to the print receiving surface. The print wires are individually actuated by respective actuator assemblies which each include a stationary portion consisting of an end plate, a bobbin, a solenoid winding, and a spring, and a movable portion consisting of a magnetic armature attached to the associated print wire. Upon energization of the solenoid winding the resulting magnetic flux displaces the magnetic armature and causes the print wire to impact the print-receiving surface.

Abstract: A control system for controlling a motor having a plurality of electromagnetic field windings adapted to be separately energized by switching circuitry to control rotation of a rotor in the motor. Digital circuitry generates a plurality of logic signals, one for each respective motor field winding to cause the switching circuitry to energize the field windings in a two phase on mode, a one phase on mode, or in one of a plurality of fractional phase on modes. A signal command source provides a plurality of digital signals to select or gate the desired phase on energization mode of the field windings in response to a feedback signal derived from detecting rotary movement of the rotor. Related methods of controlling a multi-phase motor with digitally generated variable phase modes are also disclosed.

Abstract: A motor control system for use in a high speed teleprinter or the like for controlling the rotational position and movement of a rotor, and apparatus driven by the rotor, by detecting back EMF induced into an unenergized field winding by rotational movement of the rotor. The output and input terminals of a first amplifier responsive to a first motor control signal, and a second amplifier responsive to a second motor control signal, are reactively coupled such that the amplifiers respond to either motor control signal to develop a signal simulating the signal into an unenergized winding of the motor due to mutual inductance with an energized winding. A differential voltage comparator provides a feedback signal indicative of motor performance upon comparing the simulated signal with the signal actually induced.