A dot matrix double print head including a front actuator and a rear actuator is disclosed. Each actuators has a print wire unit in which a plurality of print wires are slidably mounted, a plurality of electromagnets, and a plurality of armatures corresponding to the number of electromagnets. The length of the armature of the rear actuator is smaller than that of the front actuator, and thereby the moments of inertia of each of the armatures and print wires of both the actuators approach each other.
Resiliency of a flat spring 7 corresponding to an end print wire 12 is set to be greater than that corresponding to a central print wire 12 by varying width of an effective spring portion 7b of a flat spring piece 7A to which an armature 13 is attached depending on positions of corresponding tips of the print wires 12. Distance between a magnet yoke 5 and a core 15 provided between the flat spring 7 and a permanent magnet 4 at a position corresponding to a central print wire 12 side is set to be smaller than that at a position corresponding to an end print wire 12 side by varying it depending on positions of corresponding tips of the print wires 12.
A print head for a dot printer having a plurality of needles for printing by projecting the needles selectively from the print head. The print head has a solenoid base having a plurality of solenoids arranged in a circle thereon for driving the needles, a heat conductor having one side fixed in heat conducting relationship to one surface of the solenoid base and having a heat radiating portion extending in one direction from the solenoid base for radiating heat conducted thereto from the solenoid base, and a connecting portion extending in another direction from the solenoid base, a printed circuit board mounted on the side of the heat conductor opposite the one side, and an electrical connector for receiving a cable for supplying signals to a circuit on the printed circuit board and mounted on the connecting portion and electrically connected to the circuit on the printed circuit board.