Magnetic Compensation and Cooling Technique for a Stores Energy Print Actuator
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
A print actuator comprises a hammer block 10 with strip permanent magnet 11 and 12 mounted on the ends of pole pieces 13 and 14. Slots 15 and 16 are formed in the pole pieces 14 and 13, respectively, providing air passageways for forced air cooling of the assembly. The end section 18 is made wider than the inner sections of the pole pieces in order to compensate and offset the magnetic leakage at the end positions. The end position tooth 17 of focusing plate 22 may also be made wider than the teeth 19 to aid in this compensation. With this compensation, the spring hammer element at the end positions of each actuator block 10 is retracted and held with the same amount of force as the central hammer elements 24, resulting in identical impact forces.