Fuji Photo Film Company, Limited

Fujifilm Corporation

Mikio Ohno

Tatsuo Ishikawa

Hiroaki Araki

Tomohiro Ichikawa

Masatoshi Takahashi

Tsutomu Okita

Kiyomi Ejiri

Naoto Murao

Nobuyoshi Asada

Toshichika Aoki

Masaaki Fujiyama

Hiroshi Hashimoto

Akihiro Matsufuji

Yasuo Nishikawa

Hideomi Watanabe

Youichi Hayata

Kunihiko Honda

Masatoshi Kiyama

A leader tape has, on at least one face of a support, a coating layer that contains a powder and a binder, which is characterized in that the center line average roughness (Ra) of at least one face of the leader tape is from 10 to 60 nm, the leader tape is used in a magnetic recording and reproduction device where the line recording density is at least 100 kfci, and the difference between the recording track width and the reproduction track width is from 0 to 16 &#x3bc;m.

Leader tape, magnetic tape cartridge, and magnetic recording and reproduction method

A leader tape where an non-magnetic under layer that contains a powder and a binder and a magnetic upper layer are sequentially laminated on at least one face of a support, in which Fvalues of the support in a machine direction (MD) and in a transverse direction (TD) are from 80 to 120 MPa respectively, the Fvalue in MD is larger than that in TD, and a difference between the Fvalue in MD and that in TD is 15 MPa or less.

Leader tape and magnetic tape cartridge using the same

A magnetic recording tape comprising a nonmagnetic support and a magnetic layer containing ferromagnetic powder and a binder, wherein the nonmagnetic support has an intrinsic viscosity of from 0.40 to 0.60 dl/g and a number average molecular weight of from 12,000 to 24,000, and a distance between an apex of a maximum convexity and a valley of a maximum concavity of the nonmagnetic support on a cross section of an edge of the tape made by cutting the tape in a transverse direction is 2 &#x3bc;m or less in the transverse direction.

Magnetic recording tape

A magnetic recording medium comprising: a magnetic layer containing ferromagnetic powder and a binder; a nonmagnetic support; and a back coat layer, in this order, wherein the nonmagnetic support contains polyester having an intrinsic viscosity of from 0.40 to 0.60 dl/g and a number average molecular weight of from 12,000 to 24,000, a surface of the magnetic layer on a side not having the nonmagnetic support has a surface roughness Ra of from 1 to 5 nm, and a surface of the back coat layer on a side not having the nonmagnetic support has a surface roughness Ra of from 6 to 20 nm.

Magnetic recording medium

A leader tape in which an non-magnetic under layer that contains a powder and a binder and a magnetic upper layer are sequentially laminated on at least one side of a support, a center line average roughness (Ra) of a surface of the support is from 30 to 50 nm, and a center line average roughness (Ra) of the multi layer coated surface is larger than that (Ra) of an opposite surface of the support, and the difference is at most 4 nm.

A magnetic recording medium for being used in a write/read system in which a difference of track width between write track width and read track width is smaller than 10 &#x3bc;m, which comprises: a magnetic layer containing ferromagnetic powder and a binder; a nonmagnetic support; and a backcoating layer, in this order, at least one of the magnetic layer and the backcoating layer having servo signals for tracking control pre-recorded therein, wherein the nonmagnetic support is a film of a polyester having an intrinsic viscosity of 0.40 to 0.60 dl/g and a number average molecular weight of 12000 to 24000.

A magnetic recording medium comprising: a nonmagnetic support; an undercoat layer containing a compound polymerizable by radiation exposure; and a magnetic layer containing ferromagnetic powder and a binder, in this order wherein the undercoat layer has a thickness of from 0.1 to 1 &#x3bc;m, the binder contains a polyurethane resin having a glass transition temperature of from 100 to 200&#xb0; C., the magnetic layer has a thickness of from 20 to 150 nm, and an average particle size of the ferromagnetic powder is from 20 to 60 nm.

In one aspect, the magnetic recording medium comprises a magnetic layer comprising a ferromagnetic powder and a binder and said binder comprises polyurethane resin having a glass transition temperature of 100 to 200&#xb0; C. In a second aspect, the magnetic recording medium comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support and at least the binder comprised in said magnetic layer comprises polyurethane resin having a glass transition temperature of 100 to 200&#xb0; C. In both aspects, said magnetic layer has a thickness equal to or less than 0.15 &#x3bc;m, said ferromagnetic powder has a mean major axis length or a mean plate diameter of 60 nm or less, and said magnetic layer has a coercivity of 159 to 239 kA/m in a longitudinal or in-plane direction.

A magnetic recording medium is provided comprising a non-magnetic support and at least one magnetic layer comprising ferromagnetic metal particles principally containing iron, having a spindle shape and having an average major axis length of 0.15 &mgr;m or less, and a binder resin, and optionally further comprising, between the support and the magnetic layer, at least one adhesive layer or at least one non-magnetic layer principally containing a non-magnetic inorganic powder and a binder, and wherein center line average surface roughness Ra of the magnetic layer surface being 2 to 6 nm, said recording medium having the following properties; steel ball wear at 23&deg; C. and 70% RH being 2&times;10 to 4&times;10 mm , surface C/Fe ratio measured by Auger electron spectroscopy being 50 to 100, and coefficient of friction between the magnetic layer surface and an SUS rod having a roughness of 8 to 10 nm being 0.2 to 0.3.

Magnetic recording medium comprising spindle-shaped ferromagnetic metal particles

A magnetic recording medium is formed from a non-magnetic support, and a magnetic layer formed on the support and including mainly a binder resin and a ferromagnetic metal powder including mainly Fe. The magnetic layer includes an abrasive and a lubricant. The abrasive present on the surface of the magnetic layer satisfies the relationship 0.01&lE;H /H &lE;0.3 where H denotes the number of particles per unit area having a height less than 10 nm (particles/&mgr;m ) and H denotes the number of particles per unit area having a height equal to or greater than 15 nm (particles/&mgr;m ). The magnetic recording medium has a surface lubricant index of 3 to 11. The height of the abrasive particles can be controlled by, for example, a blade treatment using an abrasive tape (LTBL system) or a diamond powder-studded rotating roll (DWBL system).

Provided is a thin magnetic tape with good tracking and very little output variation in VTRs. The magnetic tape comprises a flexible support, a magnetic layer provided on one side of said flexible support and a backcoat layer provided on the reverse side of said flexible support. The magnetic tape has a stiffness equal to or less than 70 mg&middot;mm in the width direction, an average meandering amount of a tape edge trajectory traced by each of both end in the width direction of said tape observed from the direction perpendicular to said magnetic layer surface is equal to or less than 15 &mgr;m in every end, and an intensity of a meandering component having a cycle of 20 to 200 mm is equal to or less than 30 percent of the intensity of a meandering component having a cycle of 20 to 10,000 mm.

Magnetic tape having specific meandering features

A magnetic recording medium having little head staining and favorable dropout and error rates when recording after extended or high-temperature and -humidity storage. The medium has, on a nonmagnetic support, a magnetic layer of coated ferromagnetic metal powder containing Fe and binder. The ferromagnetic metal powder contains at least Al, Co and Y, and, respectively, has ratios of Al to Fe (Al/Fe) ranging from 5 to 15% by atom, Co to Fe (Co/Fe) from 1 to 25% by atom, and Y to Fe (Y/Fe) ranging from 0.5 to 5% by atom. Si and Nd either are absent or are each found in an amount not more than 0.01% by atom with respect to Fe. The magnetic layer contains a fatty acid and a fatty acid ester, the fatty acid ester being a fatty alkyl ester compound having an acid-hydrolytic speed not more than 0.03/hour

A magnetic recording medium is disclosed, comprising a nonmagnetic support having provided on a first side of the support a magnetic layer containing a ferromagnetic powder and a binder, the ferromagnetic powder is a ferromagnetic metal powder having a water-soluble calcium content of 100 ppm or less, and the ratio of widthwise stiffness (TD) to lengthwise stiffness (MD) of the magnetic recording medium is in the range of from 0.65 to 1.00. In a preferred embodiment, the magnetic layer contains a saturated aliphatic acid having 14 to 24 carbon atoms, the magnetic layer has a dry thickness of from 0.5 to 3.5 .mu.m, the nonmagnetic support has a thickness of from 8 to 11 .mu.m, and the magnetic recording medium further comprises a backing layer having a dry thickness of from 0.1 to 1.0 .mu.m.

A method for preparing a magnetic recording medium is disclosed, comprising the steps of (1) surface-treating ferromagnetic particles with a glycidyl compound having a molecular weight of 1,000 or less and having an epoxy equivalent of 200 g/eq. or less, (2) dispersing the surface-treated ferromagnetic particles with a binder to prepare a magnetic coating composition, (3) coating the resulting magnetic coating composition on a nonmagnetic support, and then (4) drying the magnetic coating composition.

Growing community of inventors

Kanagawa, Japan

Mikio Ohno