Fuji Photo Film Company, Limited

Hiroo Inaba

Shinji Saito

Kiyomi Ejiri

Satoru Hayakawa

Masaki Suzuki

Hiroshi Ogawa

Hiroaki Takano

Kazuaki Taga

Masatoshi Takahashi

Satoshi Matsubaguchi

Hitoshi Noguchi

Toshihiko Miura

Koichi Yamauchi

Akihiro Matsufuji

Yuichiro Murayama

Noburo Hibino

Koji Naoe

Takeshi Kakuta

Kouichi Masaki

Yasuyuki Yamada

Naoto Abe

Takahito Miyoshi

Osamu Iwasaki

Naoyoshi Chino

Nobuo Yamazaki

Toshiyuki Kitahara

Hiroaki Doushita

Takeshi Tsuda

Kazuko Hanai

Nobuyuki Yamamoto

Akira Ushimaru

Takeshi Harasawa

Keiji Mori

Takeshi Nagata

Jun-ichi Nakamikawa

Kiyoma Ejiri

Toshiharu Takeda

Satoshi Matsubagichi

Kenzo Iwamoto

A magnetic recording tape is described, which comprises a plastic support having provided thereon a magnetic layer comprising a ferromagnetic metal powder dispersed in a binder, wherein the magnetic layer has the product P of the coercivity Hc (Oe) in the in-plane machine direction of the tape and the magnetic flux &phgr;m (G&middot;cm) of from 100 to 160.

Magnetic recording tape with controlled Hc and magnetic flux/unit area value and controlled Cl/Fe intensity

The magnetic tape processing method and apparatus allow at least one of a laser beam or laser beams in a visible region and a laser beam or laser beams in an ultraviolet region to be incident on a backing layer of a magnetic tape while transporting the magnetic tape in a lengthwise direction of the magnetic tape and process the backing layer by means of the laser beam or laser beams to form recesses on the backing layer. The processed magnetic tape is composed of a base layer, a magnetic layer formed on one surface of the base layer and the backing layer formed on another surface of the base layer and having recesses which are formed by processing the backing layer by means of the laser beam or laser beams. The method and apparatus can efficiently manufacture the magnetic tape having excellent characteristics such that the occurrence of the slip of the magnetic tape is not caused on a capstan roller and the like, even if the transportation speed of the tape is increased in a magnetic tape manufacturing apparatus, and furthermore a size of cupping of the magnetic tape is small.

Magnetic tape processing method and magnetic tape processing apparatus having an optical system

A magnetic recording medium using a biaxially oriented aromatic polyamide film as a nonmagnetic support resulting in hardly any improper windings or edge damages. The magnetic recording medium includes a magnetic layer containing ferromagnetic powders dispersed in a binder formed on the nonmagnetic support, wherein the biaxially oriented aromatic support has a ratio of the loss tangent at a temperature of 40&deg; C. to the loss tangent at a temperature of 100&deg; C. of 0.7 or higher.

Magnetic recording medium

A magnetic recording medium is disclosed, comprising a non-magnetic support having provided thereon at least a lower non-magnetic layer comprising a binder having dispersed therein a non-magnetic powder and an upper magnetic layer comprising a binder having dispersed therein a ferromagnetic powder which has been coated on said lower non-magnetic layer while the lower non-magnetic layer is wet, wherein the upper magnetic layer has an average dry thickness (d) of not more than 1.0 &mgr;m and an average thickness variation (,d) at the interface between the upper magnetic layer and lower non-magnetic layer is not more than d/2. The magnetic recording medium exhibits excellent electromagnetic characteristics, running properties, and durability.

A magnetic recording medium is disclosed, comprising a non-magnetic support having provided thereon at least a lower non-magnetic layer comprising a binder having dispersed therein a non-magnetic powder and an upper magnetic layer comprising a binder having dispersed therein a ferromagnetic powder which has been coated on said lower non-magnetic layer while the lower non-magnetic layer is wet, wherein the upper magnetic layer has an average dry thickness (d) of not more than 1.0 .mu.m and an average thickness variation (.sup..DELTA. d) at the interface between the upper magnetic layer and lower non-magnetic layer is not more than d/2. The magnetic recording medium exhibits excellent electromagnetic characteristics, running properties, and durability.

A cleaning medium for magnetic recording devices comprises a non-magnetic substrate, a lower coating layer, which is overlaid upon the non-magnetic substrate and primarily contains a binder and non-magnetic inorganic particles dispersed in the binder, and a cleaning layer, which is overlaid upon the lower coating layer and contains a binder and inorganic particles dispersed in the binder and at least containing ferromagnetic particles. An at least 50% by weight portion of the non-magnetic inorganic particles, which are contained in the lower coating layer, is constituted of granular inorganic particles, which have a mean particle diameter of at most 0.08 .mu.m, or acicular inorganic particles, which have a mean longer axis length falling within the range of 0.05 .mu.m to 0.3 .mu.m and an acicular ratio falling within the range of 3 to 20. The cleaning medium removes dirt from magnetic heads with high cleaning power, such that the wear of the magnetic heads may be small and no scratch may occur on the cleaned magnetic heads.

Cleaning medium for magnetic recording devices

A magnetic recording medium is disclosed, which comprises a support having thereon a magnetic layer comprising a binder and a ferromagnetic powder dispersed therein, wherein said binder comprises a polyurethane resin having at least one cyclic hydrocarbon group and at least one ether linkage, and said ferromagnetic powder is a ferromagnetic metallic powder which comprises Fe and has a mean major-axis length of from 0.05 to 0.19 .mu.m and a crystallite size of from 100 to 230 .ANG.; and further a magnetic recording medium is disclosed, comprising a support having thereon in succession an undercoat layer comprising a binder U and an inorganic powder dispersed therein and a magnetic layer comprising a binder M and a ferromagnetic powder dispersed therein, wherein at least either of the binder U or M comprises a polyurethane resin having at least one cyclic hydrocarbon group and at least one ether linkage and said ferromagnetic powder is a ferromagnetic metallic powder which comprises Fe and has a mean major-axis length of from 0.05 to 0.19 .mu.m and a crystallite size of from 100 to 230 .ANG..

A magnetic recording medium is disclosed, comprising a nonmagnetic support having thereon at least two coating layers which comprise:

A magnetic recording medium is disclosed, comprising a non-magnetic support having provided thereon at least a lower non-magnetic layer comprising a binder having dispersed therein a non-magnetic powder and an upper magnetic layer comprising which has been coated on said lower non-magnetic layer while the lower non-magnetic layer is wet or in a dry state, wherein the coating solution for the lower non-magnetic layer having a thixotropic property and the lower non-magnetic layer containing either (a) an acicular inorganic powder having a Mohs hardness of 3 or more and a major axis length of 0.3 .mu.m or less or (b) a spherical inorganic powder other than carbon black having an average primary particle size of 0.08 .mu.m or less. The magnetic recording medium exhibits excellent electromagnetic characteristics, running properties, and durability.

A magnetic recording medium is disclosed, comprising a lower coating layer mainly comprising an inorganic powder and a binder provided on a non-magnetic support, and one or more magnetic layers comprising at least a ferromagnetic metal powder and a binder provided on the lower coating layer, wherein the thickness of said magnetic layers is from 0.05 .mu.m to 0.8 .mu.m and the magnetic particle incorporated in said magnetic layers comprises Fe as a main component, Co in an amount of from 10 atm-% to 40 atm-% and Y is an amount of from 1.5 atm-% to 10 atm-%, based on Fe.

A magnetic recording medium comprises a non-magnetic substrate, a lower coating layer, which is overlaid upon the non-magnetic substrate and primarily contains a binder and inorganic particles dispersed in the binder, and a magnetic layer, which is overlaid upon the lower coating layer and is constituted of at least a single layer. The magnetic layer contains at least a binder and ferromagnetic metal particles dispersed in the binder. The thickness of the magnetic layer falls within the range of 0.05 .mu.m to 0.5 .mu.m. The surface roughness of a top magnetic layer is at most 3 nm. The lower coating layer contains a fatty acid. An increase in the number of small protrusions, which have a height of at least 30 nm, does not occur substantially on the surface of the magnetic layer after the magnetic recording medium has been stored for seven days under environmental conditions of a temperature of 60.degree. C. and a relative humidity of 90%.

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Kanagawa, Japan

Hiroo Inaba