Multiple coil hammer actuator system

A multiple coil/hammer actuator system for a dot matrix line printer wherein images are created by controlling the printing of dots in dot lines across a print receiving medium as the print receiving medium is stepped in a direction transverse to said dot line, said multiple coil/hammer actuator system comprising:

• a plurality of coils, mounted side-by-side in a fixed position and along a common axis lying transverse to the direction of movement of said print receiving medium, for producing adjacent magnetic fields when energized;
• a plurality of resilient hammer means, smaller in number than the number of coils, mounted for oscillatory movement in the adjacent magnetic fields produced by said plurality of coils and between said plurality of coils and said print receiving medium, said oscillatory movement being such that at least a portion of each hammer means moves in the region where the magnetic fields are produced by at least two adjacent coils when said at least two adjacent coils are energized, said portion of said hammer means being formed of a ferromagnetic material that is attracted toward said at least two adjacent coils when one or both of said two adjacent coils are energized, said attraction acting against said resilience of said resilient hammer means to create stored mechanical energy that is released when the energized one or both of said at least two adjacent coils is de-energized, said release creating a dot producing hammer actuation force;
• and,
• control means connected to said plurality of coils for controlling the energization of said plurality of coils such that one or both of the two adjacent coils related to each of said hammer means is selectively energized in accordance with the position of said related hammer means in the region where magnetic fields are produced by said at least two adjacent coils and the nature of a dot control signal.