A high speed print pin driver for a dot matrix printer. A U-shaped core having a pair of parallel spaced legs is formed of a plurality of laminations of silicon iron. A rectangular magnetic field-forming coil is on one of the legs. A magnetic flux plate of silicon iron is disposed across the open end of the U of the core between the legs, the flux plate being attached to the other of the legs and in close-spaced adjacent relationship to the one of the legs. The top surface of the flux plate over the other leg is slightly longitudinally beveled and the flux plate has a bore therethrough over the one of the legs and longitudinally aligned therewith. A longitudinal spring-metal beam is disposed along the flux plate, being attached on one end to the beveled top surface and extending out over the flux plate on the other end. The beam includes an armature piece of magnetically attractable material disposed within the bore in the flux plate. The beam tapers from adjacent the armature piece to the other end thereof and has one edge forming a reinforcing rib along the tapered portion. A print pin is carried by the other end of the beam disposed substantially parallel to the one leg of the core.