| 摘要 |
PURPOSE:To miniaturize a magnetic latent image forming apparatus by housing a magnet for forming a magnetic bias field in a roll facing to a thermal printing head and locally heating a magnetic medium by using a selected heating element in order to form a magnetic latent image having a magnetized pattern different from the other portions. CONSTITUTION:First, a magnetic medium 3 is saturatedly magnetized in the directions of thickness, in-surface and the like to form a uniform magnetized pattern. Then, when coming to directly below a thermal printing head 1, the magnetic medium 3 is locally heated by a selected heating element 11. The temperature of the heated portion is raised above the Curie point or the temperature of the compensation point, so that the magnetization of the heated portion disappears. When the current supply to the heating element 11 stops, the temperature of the magnetic medium 3 lowers, so that the heated portion is magnetized by the magnetic field of a bias magnet 5 at a temperature below the Curie point or the like. The heated portion is magnetized in the direction determined by the magnetic field of the magnet 5. Therefore, a magnetic latent image having a pattern different form the preliminary magnetization can be obtained. |
