Abstract: A process for the production of a magnetic recording member which comprises effecting electric field vapor deposition under conditions such that the angle of incidence at which the vapor beam of a ferromagnetic metal strikes a support is at least about 50.degree. and the electric field between the support and a vaporization source is at least about 5 kv/m.

Abstract: A magnetic recording medium is described comprising a protective layer including at least one substance selected from the group consisting of poly(paraxylylene), poly(monochloroparaxylylene), and poly(dichloroparaxylylene) formed on a magnetic recording layer comprising a thin ferromagnetic metal film.

Abstract: A recording medium and, more particularly, a recording medium based on a composition exhibiting high dispersibility for finely-divided ferromagnetic powders having excellent abrasion resistance is disclosed in which the magnetic composition comprises a finely-divided ferromagnetic powders dispersed in a binder containing 2-chloroacrylonitrile polymer and a polyurethane prepolymer; in another embodiment of the invention the magnetic composition additionally contains a polyisocyanate compound.

Abstract: A magnetic head assembly for recording and playing back information on a recording medium in a vertically magnetized mode. Main and auxiliary heads are provided opposite one another with the recording medium passing therebetween. The main head includes a core of material exhibiting a magnetoresistance effect to which core are attached leads which carry the output play back signal. The auxiliary head has a magnetic core around which is wrapped a winding carrying the recording current. The recorded information patterns have their primary magnetic field components perpendicular to the surface of the recording medium.

Abstract: A process for producing a cobalt-containing ferromagnetic iron oxide powder suitable for magnetic recording which comprises(a) mixing cobalt ion, ferrous ion and an alkali with an aqueous dispersion of acicular ferromagnetic iron oxide nuclei under non-oxidizing conditions at a temperature of about 50.degree. C. or less;(b) heating the dispersion to a temperature of at least about 60.degree. C. but below the boiling point of the dispersion under non-oxidizing conditions to cause a reaction; and(c) treating the dispersion at a temperature of at least about 60.degree. C. but below the boiling point of the dispersion under the following conditions:(1) initially treating the dispersion under non-oxidizing conditions for about 5 minutes or more;(2) subsequentially treating the dispersion under oxidizing conditions for about 5 minutes or more prior to the termination of the reaction; and(3) a total treating time under non-oxidizing conditions and oxidizing conditions of at least about 30 minutes.

Abstract: A method of producing a magnetic recording layer on a support comprising simultaneously depositing a ferromagnetic material and a polymer on a support using a vapor deposition technique such as vacuum deposition, sputtering, etc., thereby to produce thereon a magnetic recording layer of a composite film of the ferromagnetic material and the polymer. A further embodiment for producing a magnetic recording layer comprises simultaneously depositing a ferromagnetic material and a monomer or oligomer on the support using a vapor deposition technique, polymerizing the deposited layer, e.g., using a polymerization catalyst or by applying ionizing or electromagnetic rays thereto, to form a composite film of the ferromagnetic material and the polymer. The magnetic recording layer thus obtained in either embodiment can be used for high density recording.

Abstract: The inner surface of a disc jacket for retaining a magnetic recording disc is provided with a fibrous layer containing an antistatic agent. The fibrous layer is composed of a nonwoven cloth impregnated with the antistatic agent. The antistatic agent may be applied to the nonwoven cloth by spraying instead of impregnation.

Abstract: A magnetic recording medium excellent in adhesiveness and surface property is produced by a process comprising treating the surface of a plastic substrate by glow discharge, then subjecting the substrate to a surface activating treatment and forming a magnetic metallic plating layer on the surface of the substrate by an electroless plating method.

Abstract: In a magnetic sheet recorder, a scraping member is mounted in association with a magnetic head to be put into contact with the magnetic layer of a magnetic sheet together with the magnetic head. The scraping member is mounted ahead of the head so as to treat the recording track of the magnetic sheet in advance of the head when the magnetic sheet is rotated. The scraping member removes from the surface of the magnetic layer scratches and dust particles which cause drop-out of the output level.

Abstract: This invention relates to a process for the production of a magnetic recording medium, which comprises heating a substrate or subbing layer containing copper as a main component at a temperature of about 100.degree. to 350.degree. C. and, at the same time, vapor depositing in vacuum a ferromagnetic metal containing cobalt as a main component on the substrate or subbing layer to thus form a magnetic recording layer.

Abstract: A magnetic iron oxide having a large coercive force and an improved squareness ratio prepared by coating the surface of needle-like particles of magnetic iron oxide with a cobalt compound, placing the coated iron oxide particles in a unidirectionally oriented magnetic field thereby orienting the particles in the direction of the magnetic field, and heat-treating the needle-like particles in this state with the application of an external magnetic field, or heat-treating the needle-like particles in a magnetized state.

Abstract: A process of producing a magnetic recording element comprising a non-magnetic support having provided thereon a subbing layer and further having provided thereon a magnetic layer comprising a ferromagnetic powder and a binder, in which the non-magnetic support is a biaxially stretched polyester and the subbing layer is formed by coating a coating solution having a solids concentration of about 0.8 to about 5 wt% comprising an amorphous linear saturated polyester resin containing an aromatic dicarboxylic acid, 10 to 50 wt% of a vinylidene chloride addition polymerizable nitrile copolymer based on the polyester resin and an organic solvent mainly composed of methyl ethyl ketone, which comprises coating the subbing solution at a temperature of about 100.degree. C. or below to provide a dry thickness of about 0.03 to about 2.0 .mu.m, drying the coated layer and then coating the magnetic recording layer thereon.

Abstract: A magnetic Fe oxide containing Co, and optionally, a divalent metal, in which the oxidation degree indicated by the following formula ranges from about 30% to 80%; ##EQU1## wherein y is the amount of the Co, plus the divalent metal if present, in atomic % contained in the magnetic Fe oxide, and R is the ratio of the divalent Fe ion to the total Fe ions;and a process for producing a magnetic Fe oxide containing Co, and optionally, a divalent metal, and having an oxidizing degree of about 30 to 80%, which comprises dehydrating and reducing goethite containing Co, and optionally, the divalent metal, to obtain magnetic containing Co, and optionally, a divalent metal, and oxidizing gradually the magnetite at a relatively low temperature of lower than about 100.degree. C.

Abstract: This invention relates to a magnetic recording medium comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, in which the surface roughness of the support is 0.10 .mu.m or less and the period of the surface roughness is v/10.sup.6 .mu.m or less where v represents a relative speed between a magnetic head and magnetic recording medium by .mu.m/sec. In the case of providing an undercoated layer between the magnetic recording layer and non-magnetic flexible support, the surface roughness of the undercoated layer is adjusted to 0.10 .mu.m or less and the period of the surface roughness is adjusted to v/10.sup.6 .mu.m or less.

Abstract: A process for producing a ferromagnetic powder comprising injecting a stream of an aqueous solution of a metal salt capable of forming a ferromagnetic substance and a stream of solution containing a reducing material for mixing into a reaction chamber such that the two solutions impinge upon one another causing an oxidation-reduction reaction between them to occur, and applying a magnetic field of 50 oe or more to the particles produced by the oxidation-reduction reaction for the period during which the particles become ferromagnetic particles after going through a superparamagnetic state and an apparatus for use in the practice of the above process comprising a reaction vessel, at least one nozzle for injecting each of a solution of a metal salt and a solution containing a reducing material into the reaction vessel and a magnet for producing a magnetic field in the reaction vessel with the nozzles being open to the magnetic field and positioned so that the solution of the metal salt and the solution of the r

Abstract: A magnetic recording and reproducing apparatus provided with a magnetic head device comprising a supporting means having a recording magnetic head made of an alloy system magnetic material and a reproducing magnetic head made of a ferrite system magnetic material. The recording and reproducing heads are fixed relative to one another thereby eliminating the need for completely separate head mechanisms and for complex mechanisms to reliably interchange the positions of the two heads relative to the recording medium.

Abstract: The process for the production of a magnetic recording medium by electroless plating comprises carrying out the plating in a plating aqueous solution containing at least one ferromagnetic metal ion, barium ion and hypophosphite ion as a reducing agent, and thus forming a magnetic metal thin film.

Abstract: In a process for producing a ferromagnetic powder having a high coercive force which comprises adding an aqueous solution containing Co.sup.+2 ions, or both Co.sup.+2 ions and another cation(s), and an alkali solution to a suspension of a ferromagnetic iron oxide containing the metal(s) given by these ion(s), the improvement wherein said ferromagnetic iron oxide is treated with a reducing agent prior to the preparation of the suspension.

Abstract: A method for electroplating in a single electroplating bath comprising varying the electric current density so that a non-magnetic plated film and a ferromagnetic plated film are selectively deposited. To achieve this effect the electroplating bath must contain at least about 1 g/l NaH.sub.2 PO.sub.2.H.sub.2 O.

Abstract: In ferromagnetic powders mainly composed of iron oxide, the ferromagnetic iron oxide(s) comprise a superparamagnetic material which provides a peak showing superparamagnetism by measurement of the Mossbauer Effect spectrum. The ferromagnetic iron oxides are suitable for making highly sensitive magnetic recording media having excellent frequency response with lowered modulation noise.