Abstract: A ribbed ring for winding a magnetic tape cut in narrow width is disclosed which has an annular outer peripheral part and a groove for reinforcing the ring against deformation and a rib for fitting to a groove of an adjacent ring and an annular inner peripheral part having one or more slits for fitting to a spline shaft.

Abstract: A magnetic tape cassette has a tape pad for pushing the magnetic tape in the path of the magnetic tape. The tape pad comprises one piece of a tape contacting part and a spring member for supporting the tape contacting part which is made of a carbon-containing polymer having elasticity.

Abstract: A tape cover formed by molding an L-shaped body of an upper plate and a front plate in one piece in which an erroneous insertion detecting notch is formed in the joint portion of both the plates comprises an injecting port as a gate positioned on a side surface of said upper plate in said notch, and the thickness of the wall of said upper plate just below said injecting port is larger than that of the other part of the wall of said upper plate near said injecting port wall.

Abstract: A tape cover made of resin comprises a single-piece L-shaped body of an upper plate and a front plate and an erroneous insertion detecting notch formed in the joint of the plates, wherein a gate is formed in the notch and the thickness of the wall of a portion adjacent the notch in the upper plate is smaller than the distance from the edge of the upper plate to the most remote part of the diameter of the gate.

Abstract: A magnetic recording medium having a substrate coated with a magnetic layer comprises a binder, a magnetic powder and a metal phosphide at a ratio of 0.2 to 5.0 wt. % based on said magnetic powder.

Abstract: A fitting piece is adapted to fit in a recess for receiving an actuation pin of a recorder. The fitting piece comprises a middle portion; a pair of legs vertically extending the ends of the middle portion; and a cooperative lug formed on the leg. The fitting piece can be fitted into the recess in two different positions either permitting recording or preventing cancellation of the recorded sound.

Abstract: A magnetic tape cassette comprises a pad support membrane made of a metal alloy such as bronze and nickel silver. The pad support membrane is coated with a synthetic resin layer containing a rust inhibitor.

Abstract: A cleaning tape for a magnetic recording apparatus comprises a substrate coated with a cleaning layer comprising magnetic iron oxide power as a main component and a non-magnetic abrasive power having Moh's scale of hardness of at least 6 and a binder wherein said cleaning layer has a surface roughness of 0.5 to 5 .mu.m and a ratio of said abrasive powder to iron oxide powder of 0.3 to 40 wt. % and especially 3 to 40 wt. % in the case of said surface roughness of 0.5 to 1 .mu.m; 0.5 to 20 wt. % in the case of said surface roughness of 1 to 2 .mu.m; 0.3 to 10 wt. % in the case of said surface roughness of 2 to 5 .mu.m.

Abstract: A case for holding a magnetic tape cassette comprises a case body and a cover pivotally joined together by a pair of pivots fitted in corresponding pivot-receiving holes, with arcuate protuberances formed respectively around the pivots and pivot holes in such a manner that, when the pivots have been fitted in the holes, the both protuberances coact to keep the opposing side walls of the case body and the cover apart from each other, the protuberances themselves being arranged so as not to overlap each other. The pivots protrude inwardly from the side walls of the case body, the pivot holes are formed in the side walls of the cover, and the arcuate protuberances are formed, one for each, on the inner faces of the side walls of the case body and on the outer faces of the side walls of the cover. The protuberances of the case body are formed to extend semicircularly through an angle of 180 degrees around the pivots, and the protuberances of the cover extend through an angle of 90 degrees around the pivot holes.

Abstract: A lubricant sheet for a magnetic tape cassette characterized in that at least one side of a base incorporating an antistatic agent is provided with a release type silicone coating. This lubricant sheet combines the transparency derived from the use of the clear base and coating materials with the low friction characteristic and the antistatic property to suit the application as such for transparent tape cassette cases.

Abstract: A tapping boss formed in one piece with the upper half casing for joining the lower half casing of a magnetic tape cassette comprises a stem having a cross sectional area slightly larger than the diameter of a tapping screw to receive the screw and a plurality of ribs which project radially from the cylindrical surface of said stem and whose top portions provide contact shoulders for the boss supporter of a lower half casing.

Abstract: A magnetic tape cassette having one or more guide pole which is forcibly inserted at each end into each axial hole formed in a casing comprises an air releasing portion for releasing air during the forcible insertion of said guide pole in said axial hole.

Abstract: A magnetic recording medium having multi-layer structure of two or more thin metallic layers on a substrate. The orientations of metallic particles are different for each of said thin metallic layers.

Abstract: In elliptical shaped insulated high voltage ceramic capacitors, subjected to higher heat and temperature, stresses are formed which causes gaps between the insulation and ceramic capacitor. To solve this and other problems a hollow elliptical shaped plastic cover is positioned below the capacitor ground conductor. The cover has a bridge which separates the cross section of the cover into two substantially circular areas an insulator is injected into the cover which also covers the capacitor.

Abstract: A urethane resin comprising the reaction product of a C.sub.4 -C.sub.8 alkylenediisocyanate as an isocyanate component and a C.sub.3 -C.sub.12 alkyleneglycol as a polyol component is used as a rubber component for a binder in a magnetic layer of a magnetic recording medium.

Abstract: A magnetic recording medium having a substrate coated with a magnetic layer comprising a magnetic powder and a binder essentially consisting of 20 to 70 wt. % of a polyester resin, 80 to 30 wt. % of a vinyl chloride-vinylidene chloride copolymer and a polyisocyanate.

Abstract: A magnetic recording medium comprises a first magnetic layer containing magnetite or a cobalt doped magnetite which is coated on a non-magnetic substrate; and a second magnetic layer coating a cobalt doped .gamma.-Fe.sub.2 O.sub.3 which is coated on said first magnetic layer.The magnetic recording medium has a high recording sensitivity, a high dynamic range, a less output fluctuation and especially superior sensitivity in low frequency band and superior maximum output level without a deterioration of transfer characteristics.

Abstract: A magnetic recording medium has a substrate coated with a magnetic powder and a binder. The binder in said magnetic layer essentially consists of 15 to 45 wt. % of a polyester resin, 20 to 50 wt. % of an epoxy resin and 10 to 40 wt. % of nitrocellulose.

Abstract: A thermal pen tip comprising a heat reserve layer formed on an insulating substrate; a resistance layer for heating formed on said heat reserve layer; and a protective layer formed on said resistance layer, wherein said heat reserve layer has a convex top having a curvature and a flat surface on said convex top, so as to have a size corresponding substantially to a width of a line and said resistance layer for heating is formed on said flat surface of said heat reserve layer.

Abstract: A magnetic tape cassette having a tape guide coated with nickel-tin alloy plating on the surface which is in slide-contact with a magnetic tape.