| 摘要 |
<p>Electromagnetic drive device for the printing needle of a needle printing head comprising an E-shaped magnetic yoke, the central arm (13) of which carries an electrical exciter coil (14), and an elongated tilting armature (15), one end of which is tiltingly arranged on or near one of the outer arms (11, 12) of the magnet yoke (10) and the other end of which projects above the other outer arm (12) of the magnet yoke (10) and acts on the printing needle. In order to improve the printing speed, the strike through rate and the service life, the drive device is designed so that an iron path constituted by the central arm (13) and one of the outer arms (11, 12) has an average length of less than 30 mm, the magnetic circuit has an inductivity less than 3 mH, the tilting armature (15) is wider than the arms of the magnet yoke (11, 12, 13) over its whole length opposite the tilting armature (11, 12, 13) and this tilting armature has a magnetically active cross-section 10 to 50 % less than that of one of the outer arms (11, 12).</p> |
