Abstract: An actuator assembly for a dot matrix printer of the stored energy type in which a plurality of flexible spring hammer elements are mounted in an interleaved arrangement in order to provide a compact structure. The actuator assembly includes a mounting block having upper and lower magnetic circuits and spring hammers attached to it. A portion of the magnetic circuits is coupled to the rear of the mounting block in order to facilitate heat dissipation from the actuator. The pole pieces of the magnetic circuits are positioned to reduce resonance of the spring hammers to thereby decrease cycling time. Permanent magnets utilized in the assembly are arranged in a non-symmetrical fashion in order to increase the magnetic efficiency of the device. Integrally connected pole pieces and permanent magnets are used in the assembly to reduce manufacturing costs without degrading performance.