| 摘要 |
PURPOSE:To prevent the deformation of a magnetic core due to the rise of temperature by providing a thermal deformation buffer having a smaller thermal expansion coefficient than a casing material to the casting material portion of a printing head into which a wire ring, the magnetic core, a yoke, and a permanent magnet are confined and solidified with the casing material. CONSTITUTION:In confining and solidifying a magnetic core 2, a wire ring 3, a yoke 1, and a permanent magnet 4 into a printing head consisting of the magnetic core 2, the wire ring 3, the yoke 1, the permanent magnet 4, a supporter 6, a submagnetic path 8, and an armature 5 by using a casting material 15, e.g., epoxy resin, etc., a thermal stress buffer plate 16 formed of a metal, e.g., stainless steel, etc., having a smaller thermal expansion coefficient than the casting material 15 is provided as a thermal deformation buffer. In making printing by flowing switching current to be controlled at high speed to the wire ring 3, the wire ring 3 is energized to heat the casing material 15, where a heat stress is generated due to the difference in thermal expansion coefficients between the metal portion, e.g., the yoke 1 and the magnetic core 2, etc., and the casing material 15. This heat stress is applied to the buffer plate 16, and thereby the heat stress to be applied to the magnetic core 2 is lessened and the deformation of the magnetic core 2 is therefore prevented. |
