JPS5584041A

JPS5584041A - Magnetic recording medium

Info

Publication number: JPS5584041A
Application number: JP15888578A
Authority: JP
Inventors: Akira Matsumoto; Shoichi Sakamoto
Original assignee: Hitachi Maxell Ltd
Current assignee: Maxell Holdings Ltd
Priority date: 1978-12-20
Filing date: 1978-12-20
Publication date: 1980-06-24

Abstract

PURPOSE: To obtain a magnetic recording medium excellent in the forgery prevention with which the true signals recorded could not be read unless the fixed operation given, by forming the magnetic layer via the mixture of the high and low magnetixm keeping power magnetic powder featuring double or more difference of the magnetism keeping power between.

CONSTITUTION: The binder and the mixture of the magnetic powder of the high magnetism keeping power (about 400 Oe or more) and the magnetic powder of the low magnetism keeping power (about 200 Oe or more) are compounded in the ratio of about 80:20W60:40. Such compound is then coated onto substrate 1 to form magnetic layer 2 and then to be used as the magnetic recording medium (Fig. a). The true signals are recorded on the magnetic recording medium mentioned above via the recording current of I₂, and then the false signals are recorded via the recording current of I₁. As a result, the true signals could not be read because of coexistence of the false signals (Fig. b). Thus the erasing current of I₃ is applied to erase the false signals recorded on the low magnetism keeping power magnetic powder. As a result, the true signals recorded on the high magnetism keeping power magnetic powder can be read (Fig. c).