Fuji Photo Film Company, Limited

Akira Kasuga

Akihiro Matsufuji

Hajime Miyatsuka

Masaaki Fujiyama

Yasuyuki Yamada

Goro Akashi

Shigeo Komine

Takahito Miyoshi

Masashi Aonuma

Hajime Miyatuka

Kiyomi Ejiri

Yasuo Tamai

Osamu Suzuki

Yasuo Nishikawa

Noburo Hibino

Hiroshi Ogawa

Yasushi Hattori

Tsutomu Okita

Nobuo Tsuji

Nobutaka Yamaguchi

Takashi Yoneyama

Satoru Hayakawa

Toshimitu Okutu

Toshio Kawamata

Chiaki Mizuno

Takeshi Kakuta

Hiroaki Araki

Yoshito Mukaida

Kazuhiko Morita

Yasutoshi Okuzawa

Masaaki Suzuki

Nobuyuki Yamamoto

Yasuo Nagashima

Shizuo Umemura

Tatsuo Ishikawa

Shinobu Iida

Minoru Sueki

Tsutomu Sugisaki

Takao Ohya

Haruo Masuda

Nobuo Aoki

Kenji Sega

Masaaki Igarashi

Provided is a magnetic recording medium suited to magnetic recording and reproduction systems employing linear methods and incorporating magnetoresistive reproduction heads. The magnetic recording medium comprising a magnetic layer for servo signal recording, a nonmagnetic layer, and a magnetic layer for information recording in this order on a nonmagnetic support, wherein said magnetic layer for information recording exhibits a coercivity of at least 7.96 kA/m (100 Oe) higher than a coercivity of said magnetic layer for servo signal recording and an interface roughness at the interface of said magnetic layer for servo signal recording and said nonmagnetic layer ranges from 7 to 12 nm.

Magnetic recording medium

A magnetic recording tape favorably employable for computer data storage has a flexible polymer web, a magnetic recording layer arranged on one surface side of the web, and a backing layer arranged on another surface side of the web, characterized in that the recording tape has a thickness of 2 to 8 .mu.m and shows a Young's modulus of not less than 1,200 kg/mm.sup.2 in its longitudinal direction; and the backing layer has a thickness of 0.2 to 1 .mu.m and is composed of a binder, a carbon black, a non-magnetic powder I having Mohs' scale of hardness of 3 to 4.5 and another non-magnetic powder II having Mohs' scale of hardness of 5 to 9. Between the magnetic layer and the flexible polymer web, a non-magnetic undercoating layer composed of a binder and a non-magnetic powder can be provided.

Magnetic recording tape favorably employable for computer data storage

A novel magnetic recording medium is provided comprising a non-magnetic support having provided thereon a magnetic layer comprising a ferromagnetic powder dispersed in a binder, wherein at least one fatty acid amide compound represented by formula (I), at least one fatty acid ester represented by formula (II) and at least one fatty acid ester represented by formula (III) are provided in or on the magnetic layer: ##STR1## wherein R.sup.1 represents a C.sub.13-21 straight-chain saturated hydrocarbon group; ##STR2## wherein R.sup.2 represents a C.sub.12-21 straight-chain or branched saturated or unsaturated hydrocarbon group; and R.sup.3 represents a C.sub.1-10 straight-chain or branched saturated or unsaturated hydrocarbon group; ##STR3## wherein R.sup.4 represents a C.sub.12-21 straight-chain or branched saturated or unsaturated hydrocarbon group; R.sup.5 represents a C.sub.2-3 divalent hydrocarbon group; R.sup.6 represents a C.sub.1-10 straight-chain or branched saturated or unsaturated hydrocarbon group; and n represents an integer of from 1 to 10 where n may be the same or different when the magnetic layer contains two or more compounds represented by formula (III).

Magnetic recording medium lubricated by a three component fatty acid

A magnetic recording medium comprising a non-magnetic support having provided thereon a magnetic layer comprising a ferromagnetic powder dispersed in a binder,

Magnetic recording medium using a binder resin containing a polar group,

A method for preparing a magnetic recording medium comprising a non-magnetic support having coated thereon a magnetic layer of a magnetic coating composition containing ferromagnetic metal particles and a binder, comprising at least (1) a step of mixing and dispersing ferromagnetic metal particles, a binder, and a solvent to prepare magnetic coating composition, (2) a step of adding and mixing lubricating agent therewith and (3) a step of coating the resulting magnetic coating composition on a non-magnetic support.

Method for preparing a magnetic recording medium

A magnetic recording medium comprising a non-magnetic support having provided thereon an intermediate layer comprising carbon black, a binder and ferromagnetic particles in a weight ratio of from 5% to 25% based on the carbon black; and a magnetic layer provided on said intermediate layer, wherein said magnetic layer comprises ferromagnetic particles and a binder.

A magnetic recording medium contains in its magnetic recording layer a ferromagnetic metal powder containing an aluminum component in an amount of 1 to 6% by weight as alumnum metal, and an extremely hard abrasive such as .alpha.-alumina, chrome oxide, silicon carbide and silicon nitride. A magnetic recording medium preferably contains in its magnetic recording layer a binder comprising a resin component having a polar group.

In a magnetic recording medium such as a video tape comprising a nonmagnetic support and a magnetic recording layer provided on the support, said magnetic recording layer comprising a binder and a ferromagnetic powder dispersed therein, the improvement in which:

A magnetic recording medium comprising a nonmagnetic support and a magnetic recording layer provided on the support, said magnetic recording layer comprising a binder and a ferromagnetic powder dispersed therein, which is characterized in that said binder is composed of a resin component comprising:

A tape for cleaning magnetic head comprising a support and a cleaning layer coated on at least one surface of said support, which is characterized in that said cleaning layer contains a ferromagnetic metal powder as abrasive, the surface of said cleaning layer is a surface of center line average height of not less than 0.025 .mu.m as cut-off value of 0.08 mm, and said tape has a stiffness of not more than 2.

Tape for cleaning magnetic head

A magnetic recording medium comprising a non-magnetic support having coated thereon a magnetic layer, the magnetic layer containing (i) ferromagnetic alloy particles having an average length in the long axis of 0.25 .mu.m or less and (ii) fatty acid components comprising behenic acid in an amount of 20 to 75 wt%, stearic acid in an amount of 10 to 45 wt% and oleic acid in an amount of 10 to 45 wt% based on the total weight of the three fatty acids.

A magnetic recording medium is disclosed which comprises a non-magnetic support having provided thereon a magnetic layer containing ferromagnetic metal particles and a binder, wherein the ferromagnetic metal particles have a specific surface area of 30 m.sup.2 /g or more, and a saturation magnetization of 120 emu/g or more and have been surface-treated with an organic compound. Also, a magnetic recording medium is disclosed which comprises a non-magnetic support having provided thereon a magnetic layer containing ferromagnetic particles and a binder, wherein the ferromagnetic particles have been surface-treated with an organic compound and the binder has essentially no functional groups which adsorb onto ferromagnetic metal particles.

A heat-treating process is disclosed. The process involves cutting a polymer support for a recording medium from a web roll of a long support base into a sheet form. The sheet or sheets in a superposed state are then heat-treated while applying pressure in the range of 1 g/cm.sup.2 to 1 kg/cm.sup.2 at a temperature of 50.degree. C. to 150.degree. C. for a period of time of 15 seconds to 24 hours. The heat treating process avoids conventional problems with respect to thermal shrinkage.

Process for producing a magnetic recording medium having an improved

A tape for cleaning magnetic head comprising a support and a cleaning layer coated on said support which contains an abrasive comprising a ferromagnetic metal powder of a specific surface area in the range of 40 to 65 m.sup.2 /g as a principal component, the surface of said cleaning layer having a surface of center line average height in the range of 0.02 to 0.04 .mu.m at a cut-off value of 0.08 mm.

A flexible magnetic disc for use in combination with a magnetic head assembly which includes a regulator plate and performs magnetic recording or playback by protruding a magnetic head beyond a predetermined support level of a rotatable sheet of magnetic recording medium at least by an amount which is substantially equal to a total thickness of the recording medium. Assuming that the recording medium has a total thickness of t millimeters (mm) and a Young's modulus of E grams per square millimeter (g/mm.sup.2), a product of the Youngs's modulus E and the third power of the total thickness t, i.e. Et.sup.3, lies in a range between a lower limit of 2.5 g.mm and an upper limit of 36 g.mm inclusive of the lower and upper limits.

Growing community of inventors

Kanagawa, Japan

Akira Kasuga