Optimized wire matrix impact print head

摘要

An improved wire matrix impact print head comprising a plurality of variable length impact print wires or styli, each having an input end for receiving a propelling force and an output end for delivering an impact to a recording medium. The wire styli are extended from the input end to the output end through a stylus guide assembly where the styli are arranged at the input end of the guide assembly in an irregular oval-like configuration, to favor certain frequently used styli with less bow or bend of their paths, and the styli are arranged at the output end in a continuous linear array configuration. At the input end of the guide means the styli are supported by a bearing assembly which comprises two support plates connected to each other, each plate having a plurality of guide apertures about its outer periphery for receiving the styli. Two-pole electromagnetic actuators for selectively propelling the styli during print cycles are provided for each styli by wrapping a wire coil about one of the actuator poles. The poles of the actuator are all located in the same plane so that the air gaps between the stylus propelling means and the coil-wrapped poles are substantially uniform, thereby eliminating the need to adjust any air gaps for obtaining the desired propulsion force on the styli.