Abstract: A magnetic recording medium comprised of a support base having a magnetic recording layer positioned thereon is disclosed. The recording medium has positioned an aliphatic acid ester compound on an edge portion of the surface of the recording layer. By utilizing the aliphatic acid ester the recording medium has less audio output variation and the tracking control of the medium is improved. Further, the medium has good running characteristics and excellent sensitivity.

Abstract: A magnetic recording material comprised of a non-magnetic support base having provided thereon a magnetic recording layer on one side and the back layer on the other side is disclosed. The magnetic recording layer is comprised of ferromagnetic particles dispersed in a binder in combination with carbon black particles having an average primary particle size of 30 .mu.m or less. The back layer is comprised of a binder having dispersed therein carbon black having an average primary particle size in the range of 50 to 150 m.mu.. The magnetic recording material has improved electromagnetic properties and improved durability, particularly with respect to video S/N and dropout.

Abstract: A magnetic recording medium is disclosed which is comprised of a non-magnetic support having a magnetic layer provided thereon. The magnetic layer is comprised of two different types of carbon black having different particle sizes, a lubricant which is liquid at room temperature, a ferromagnetic powder all dispersed in a binder. A carbon black (1) has an average particle size smaller than 50 m.mu. and a carbon black (2) has an average particle size of larger than 120 m.mu.. The carbon black is present in a weight ratio of (1)/(2) within the range of 50/50 to 97/3. The magnetic recording medium has improved electromagnetic properties and running durability. In addition, the material provides an improved S/N ratio and an improved coefficient of friction.

Abstract: A magnetic recording medium is disclosed. The medium is comprised of a non-magnetic support having coated thereon a magnetic recording layer and a backing layer on the surface opposite the magnetic recording layer. The backing layer contains carbon black and the surface treated calcium carbonate dispersed in a binder. The calcium carbonate is surface treated so as to make the particles hydrophobic. Including the carbon black and the calcium carbonate in the backing layer provides a recording medium with improved durability and a reduced amount of drop out.

Abstract: A magnetic recording medium comprised of a nonmagnetic support base having a magnetic layer provided thereon is disclosed. The magnetic layer includes ferromagnetic particles dispersed in a binder in combination with carbon black particles. The carbon black particles have an average primary particle size in the range of 30 m.mu. to 50 m.mu.. Further, the carbon black is capable of the adsorption of 120 ml or more of dibutyl phthalate per 100 g of carbon black. By utilizing the particular carbon black of the present invention it is possible to obtain a magnetic recording medium having improved running properties.

Abstract: A method for producing a magnetic recording medium is disclosed. The method involves providing a ferromagnetic coating layer on a non-magnetic support base to produce a coated base. The coated base is then subjected to an atmosphere having a RH of 60% or more, prior to or during a subsequent calendering treatment. The recording medium produced has excellent surface smoothness and improved electromagnetic properties. The method is advantageous in that a substantially long period of time may pass between the coating of the ferromagnetic layer on the support and the calendering treatment without having undesirable effects on the magnetic recording medium produced.

Abstract: A magnetic recording medium is disclosed. The medium is comprised of a support base having coated thereon a magnetic layer comprised of ferromagnetic particles dispersed in a binder and further comprised of at least one anhydrosorbitol di- and/or tetra-fatty acid non-hydroxy ester. By including the particularly disclosed fatty acid non-hydroxy ester the running properties of the magnetic recording medium are greatly improved.

Abstract: A supercalendering apparatus for smoothing the surface of a web by passing it through the nip between a metal roll and an elastic roll is disclosed. The elastic roll is composed of a core metal roll having a first coating made of a fibrous material wound about the core roll and an inorganic filler loaded epoxy resin impregnated in the fibrous material, and a second coating of an inorganic filler loaded epoxy resin formed on the first coating.

Abstract: A magnetic recording medium is disclosed which comprises a nonmagnetic support and a magnetic layer formed thereon, said magnetic layer having a center-line average surface roughness of not more than 2.1.times.10.sup.-2 .mu. and at least one property selected from an average pore size of at least 500 .ANG. and a porosity of at least 30%.

Abstract: A method for producing a magnetic recording medium which comprises preparing a dispersion containing a ferromagnetic powder and a binder in the presence of non-alkali beads and coating the resulting dispersion on a non-magnetic support, and a magnetic recording medium obtained by the above method.

Abstract: In a method of making a magnetic recording sheet, a magnetic material is applied on a web in a layer consisting of a number of contiguous first strip-like zones and second strip-like zones which are alternately arranged in parallel to each other. The ratio of the width of the first strip-like zone to that of the second strip-like zone is within a range of 1:3 to 3:1. In the first strip-like zones having a width of not more than 5 mm the magnetic particles are oriented in a first direction, and in the second strip-like zones magnetic particles are oriented in a second direction which is inclined with respect to the first direction at an angle from 60.degree. to 120.degree.. With this particular orientation of the magnetic particles in the magnetic layer when the magnetic layer is applied on a web, the orientation of the magnetic particles become almost random while the magnetic layer is hardened. The magnetic recording disc thus prepared has a very low output fluctuation and a higher output level.

Abstract: A magnetic recording medium comprising a coated magnetic recording layer having video and chroma S/N ratios appropriately balanced with tape transporting characteristics is attained by controlling the magnetic layer to have a surface roughness such that the maximum value of the arithmetical average roughness (Ra) is about 80 A or greater in the surface roughness pitch region greater than about 300 .mu.m while in the surface roughness pitch region of about 5 .mu.m to about 100 .mu.m the maximum value of the arithmetical average roughness (Ra) is about 40 A or less.

Abstract: In a supercalender consisting of a metal roll and an elastic roll and smoothing a web by nipping the web between the metal roll and the elastic roll, the elastic roll satisfies the condition of:Hs(D).gtoreq.-0.1T+85under the condition of 50 to 500 kg/cm of the linear pressure between the metal roll and the elastic roll, where Hs(D) is Shore hardness D-scale of the elastic roll and T is the working temperature (.degree.C.) of the elastic roller that satisfies the condition of 60.gtoreq.T.gtoreq.120.

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: A cleaning tape used for cleaning the surface of a magnetic recording head of a tape recorder or the like consists of a substrate and a cleaning layer. The cleaning layer contains two kinds of particles. One kind of particles has a small diameter and a high hardness, and the other has a large diameter and a low hardness.

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: A soft, coarse, porous cleaning sheet 32 is adhered to the upper surface of a flat horizontal base plate 2, and has approximately the same configuration as the base plate. A floppy record disc 9 having a magnetic layer 10 is secured to the spindle 6 of a motor 5, and when the disc is rotated at a "below levitation" speed the layer 10 slidingly engages the cleaning sheet 32 and is scrape dusted clean thereby.

Abstract: A ferromagnetic metal powder obtained by a reducing reaction of wet process or dry process is brought into contact with a solution containing phosphate ion. The ferromagnetic metal powder treated in this way is favorably used for magnetic recording media, in particular, suitable for high density recording.

Abstract: A foldable jacket made of a sheet material of rectangular shape and folded at the central portion thereof to form a square base sheet and a square cover sheet. The cover sheet is provided with a cut-away portion extending from an edge opposite to the folded edge to the central part thereof. The base sheet is provided with a disc holding portion at the central part thereof to be engaged with a central hole of the disc. The disc holding portion is composed of a stem portion and engaging portions. The engaging portions are made flexible and releasably engaged with the hole of the disc.

Abstract: This invention relates to a magnetic recording medium, which comprises a first protective plating layer consisting of at least one selected from the group consisting of rhenium, osmium, ruthenium, chromium, rhodium and mixtures thereof, provided on a ferromagnetic thin layer plated on a non-magnetic base material by a plating method, and a second protective plating layer consisting of at least one selected from the group consisting of silver, gold, copper, platinum, palladium, nickel-phosphorus alloys and mixtures thereof, further provided on the first protective plating layer.