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Magnetic Field Linearization for Print Hammer Assembly

IP.com Disclosure Number: IPCOM000112515D
Original Publication Date: 1994-May-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Helinski, E: AUTHOR [+2]

Abstract

Stored energy print actuators which are used in dot band printers use permanent magnets that result in more magnetic field strength at internal positions within a print hammer assembly and a relatively lesser magnetic field strength at external positions.

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Magnetic Field Linearization for Print Hammer Assembly

      Stored energy print actuators which are used in dot band
printers use permanent magnets that result in more magnetic field
strength at internal positions within a print hammer assembly and a
relatively lesser magnetic field strength at external positions.

      Fig. 1 describes a side view of a multiple position print
hammer assembly having print hammers (1) which are retracted into a
spring loaded condition by permanent magnets (2) which produce
magnetic flux passing through print hammer (1) and into stator pole
(3) thereby attracting print hammer (1) toward stator pole (3).

      Part of the magnetic flux produced by permanent magnet (2)
passes into magnetically permeable element (4) which may be made of
1010 steel and this magnetic flux passes back into print hammer (1)
and increases the attraction of print hammer (1) to stator pole (3).

      Fig. 2 describes a partial side projected view of the lower
most magnetically permeable element (4) having vertically extending
steps (5), (6) which are above level (7).

      It has been shown that extended steps (5), (6) as shown on the
outermost external position of magnetically permeable element (4) has
the effect of increasing the field strength on end positions which
normally would have reduced magnetic field strength.  This
improvement in field strength uniformity results in more uniform
print energy and print contrast.