JPS6488906A - Magnetic head - Google Patents

Abstract

PURPOSE:To reduce the reading error of the output of a recording and reproducing head by having a different thermal expansion coefficient at a sealing material to bond the gap with an erasing head for a recording and reproducing head. CONSTITUTION:When a glass having a thermal expansion coefficient smaller than the thermal expansion coefficient of a recording and reproducing core 5 of a ferrite material is used as a sealing agent, the effective permeability of the recording and reproducing core 5 is raised, and when the glass having the thermal expansion coefficient larger than the thermal expansion coefficient of the recording and reproducing core 5 is used, the effective permeability of the recording and reproducing core 5 is lowered. The relation is in the same way applied to an erasing core 11 of an erasing head 3 and a sealing material 16. Consequently, when the effective permeability of the erasing core 11 is smaller than the recording and reproducing core 5 at the extent in which a trouble does not occur for the erasing action of the erasing head 3 and the off-track occurs at the time of recording and reproducing, the magnetic flux picked up from the peak of the recording track by the erasing head 3 is reduced, the magnetic flux to flow in the erasing core 11 is reduced, and therefore, the leakage flux to enter the recording and reproducing core 5 can be prevented and the reading error of the reproducing output from a reproducing and recording head 2 can be prevented.