Wire-matrix printers, and electromagnetic actuator mechanisms useful in

Abstract

A wire-matrix printer including a vertical column of essentially horizontal, generally parallel print wires arranged for substantially linear reciprocation along spaced, parallel printing axes. The print wires are of progressively varying length so that the lowermost wire in the column is the shortest and each successive higher wire is a predetermined amount longer than the preceding wire. Thus, the outer or actuator ends of the wires define a horizontally spaced and vertically stepped array. An array of horizontally spaced and vertically stepped electromagnetic actuators is provided, as is means for flexibly coupling each print wire to an armature portion of the actuator. Each electromagnetic actuator includes a flat, generally T-shaped armature, preferably a spring reed, and a flat, generally C-shaped magnet core. The core and reed are mounted generally parallel to each other, with the crossarm of the T facing and overlapping pole face portions defined at the inner tips of the arms of the C. The core is magnetized and demagnetized to attract and release the armature, thus reciprocating a workpiece such as a print wire coupled to the free end of the reed or armature. Further details of significance relate to the positioning and geometry of the spring-reed-and-magnet t-core actuator assembly, particularly to the pole-face geometry and operational magnetic characteristics whereby the core acts as an electromagnet when attracting the reed and as a permanent magnet when latching it in a flexed cocked position, and to the electromagnetic operating principles; to a special flexible coupling for mounting workpieces such as the print wires to the flexing spring reed; and to a special mounting assembly for an array of such actuating assemblies such as in a print head of a matrix printer.