Kabushiki Kaisha Toshiba

Tokyo Shibaura Denki Kabushiki Kaisha

Konica Corporation

Masanori Isshiki

Toshiyuki Suzuki

Hideki Takahashi

Nobuyoshi Saito

Takeo Ito

Narito Goto

Kunitsuna Sasaki

Katsuyuki Takeda

Nobuyuki Sekiguchi

Disclosed is a magnetic recording medium characterized in that plural magnetic layers are provided on a non-magnetic support, the uppermost layer of the magnetic layers contains a ferromagnetic metallic powder and/or a hexagonal system magnetic powder and a binder, at least one layer other than the uppermost layer contains Co-containing iron oxide and a binder, the film thickness of the uppermost layer is 0.5 .mu.m or less, and the surface of the uppermost layer of the magnetic layers has an R.sub.10z value of the magnetic layer defined below of 50 nm or less, by which electromagnetic conversion characteristics of a magnetic recording medium can be improved.

Magnetic recording medium

The high density slave magnetic recording media comprising on a non-magnetic substrate a magnetic recording layer coated with magnetic hexagonal ferrite powder along with a binder component to transfer the digital signals stored on the master magnetic recording media by the magnetic contact duplication process, is characterized in that the perpendicular squareness ratio of the magnetic recording layer is not less than 0.58 and is less than 0.7, center line average roughness Ra is not more than 0.01 .mu.m, and the number of convex projections whose pitches are 10 to 90 .mu.m and whose height is not less than 0.03 .mu.m pp (bottom to top) is not more than 10 per 1 mm of running direction. The slave magnetic recording media permits the functionally enough duplication efficiency of digital signals by the magnetic contact duplication process and can considerably curb the error rate during the reproduction of the duplicated digital signals.

High density slave magnetic recording media having specified

A method for contact magnetic printing of recorded information is disclosed which comprises keeping in intimate mutual contact the magnetic surface of a recorded master magnetic recording medium and the magnetic surface of a blank slave magnetic recording medium which uses hexagonal ferrite magnetic particles as the magnetic material, controlling the temperature of the two-magnetic recording media so as to lower the coercive force of the slave magnetic recording medium relative to that of the master magnetic recording medium, and applying an external magnetic field thereto thereby causing the recorded information to be magnetically printed from the master magnetic recording medium to the slave magnetic recording medium. In accordance with this method, copies of pictures of high quality and sounds of highly desirable high-frequency characteristics can be produced by the contact magnetic printing technique using the slave magnetic recording medium possessing a coercive force equal to or greater than the coercive force of the master magnetic recording medium.

Method for magnetic transfer and apparatus therefor

A method for superimposed recording of a first signal and a second signal with frequency which is less than the frequency for the first signal, in a perpendicular magnetic recording medium by means of a ring-shaped magnetic head. The mutually superimposed first and second signals are supplied to the magnetic head. The value of the first signal current to be supplied to the magnetic head is set at a value which is greater than the current value for which the reproduced output level of the first signal that was recorded on the magnetic recording medium attains a maximum, and a satisfactory superimposed recording characteristic can be obtained by such an arrangement.

Method and apparatus for setting recording current in perpendicular

The thin film magnetic head in accordance with the present invention for recording information on magnetic recording medium with two channels comprises a head-forming base, a pair of head sections formed on the base with a predetermined separation, a depth detection mark formed at the center of the separation between the head sections for detecting the length of the gap depth of the head sections, and a holding plated arranged opposite to the head-forming base to hold, the head sections and the depth detection mark therebetween. The depth detection mark is so arranged as to form an isosceles triangle, with its base extending along the head-forming base situated on the side facing to the recording medium, and its vertex located, facing to the base of the isosceles triangle, on the depth end line of the gaps of the head sections, on the side which is not facing the recording medium, as well as on the center line between the head sections.

Thin film magnetic head for equalizing outputs of a two-channel tracking

A perpendicular magnetic recording head comprising a pole formed of a highly permeable magnetic thin film facing at the end thereof the magnetic surface of a recording medium, a side member formed of a highly permeable magnetic material joined with the film surface of the pole, a nonmagnetic holder for holding the pole and the side member from the side surfaces, the nonmagnetic holder having coil hole, and an exciter coil wound around the pole and the side member through the coil hole, characterized in that the coil hole is gradually increasing in width from the end of the side member toward the rear.

Perpendicular magnetic recording head

A perpendicular magnetic recording head is disclosed which includes a block core of a high magnetic permeability material having a side surface substantially perpendicular to a magnetic surface of a magnetic tape moving relative to it, a thin film core including a magnetic thin film of a high magnetic permeability material, the thin film core being secured to the side surface of the block core and having a width smaller than the width of the block core, the thin film core having a pole section extending from said side surface of the block core substantially perpendicularly to the magnetic surface and in contact therewith at the end, and an exciting coil wound on the block core and thin film core.

Growing community of inventors

Yokohama, Japan

Masanori Isshiki