Abstract: An information recording disk includes detection regions used to confirm presence or absence of written signals, read/write regions available for signal writing and write-project regions which reject signal writing. Regions where the detection regions and read/write regions overlap each other are originally provided with discriminating signals to distinguish these regions from at least the other regions. The write protect regions are distinguished from the read/write regions, referring to information detected by a head assembly.

Abstract: A magnetic head assembly including a carriage which carries thereon a first magnetic head for information writing and reading to and from one side of a disc-like magnetic recording medium, and a hold case which carries thereon a second magnetic head for information writing and reading to and from the other side of the magnetic recording medium, the second magnetic head being disposed in a position opposed to the first magnetic head, the hold case being connected to the carriage through hinge means rotatably to a certain degree relative to the carriage, and the magnetic head assembly being reciprocated in a radial direction of the magnetic recording medium. The first magnetic head is mounted on the carriage through a gimbal spring which is formed rotatably to a certain degree with respect to biaxial hinge portions, and the second magnetic head is mounted on the hold case through a spring plate which is formed rotatably to a certain degree with respect to a uniaxial hinge portion.

Abstract: A method of manufacturing a magnetic head assembly including a carriage, a lower magnetic head fixed to the carriage, a spring-loaded arm connected to the carriage, and an upper magnetic head fixed to the arm and facing the lower head, the upper and lower heads defining therebetween a clearance having a width which is equal to the thickness of a magnetic disk, the arm is so supported at its end remote from the upper head that it may be rotatable only in a direction which allows the upper head to face the lower head.

Abstract: A magnetic head having an upper head and a lower head disposed opposite to each other and capable of simultaneously reading information from or writing information in both sides of a magnetic disc inserted therein. The upper head is fixed to a wingable arm at correct vertical position and inclination, while the lower head is mounted through a gimbals spring on a carriage which is slidable along a guide rod or guide rods in the radial direction of the magnetic disc. Since the upper head is positioned correctly and the surface thereof facing the lower head serves as a datum surface, the inclination of the lower head need not be adjusted in assembling the magnetic head, and thereby the process for assembling the magnetic head is remarkably simplified.

Abstract: A disk recording-reproducing device having a carriage with a read/write head, a screw shaft to shift the carriage with an engaging element through coupling between a spiral groove of the screw shaft and the engaging element, and a stepping motor to rotate the screw shaft. The spiral groove is composed of a number of groove portions each with a straight bottom whose angle of lead is substantially zero degree that are displaced successively, circumferentially and axially. Preferably, the screw shaft has plane portions for its positioning, and a rotor of the stepping motor has magnetization points being set correspondingly to the lines of the groove portions.