Fuji Photo Film Company, Limited

Fujifilm Corporation

Other

Kiyomi Ejiri

Hiroo Inaba

Shinji Saito

Satoru Hayakawa

Koji Naoe

Masahiko Mori

Hiroaki Araki

Akihiro Matsufuji

Hiroaki Takano

Hiroshi Hashimoto

Hiroaki Doushita

Minoru Sueki

Takao Ohya

Hiroshi Ogawa

Tsutomu Okita

Masashi Aonuma

Akira Kasuga

Chiaki Mizuno

Shigeo Komine

Masaki Suzuki

Toshihiko Miura

Mikio Ohno

Yutaka Kakuishi

Kunihiko Sano

Hideaki Kosha

Noriko Inoue

Hiroyuki Tahara

Kiyoo Morita

Masatoshi Takahashi

Naoto Abe

Yasuo Nishikawa

Yuichiro Murayama

Mikihiko Kato

Kenichi Masuyama

Kouichi Masaki

Satoshi Matsubaguchi

Takeshi Harasawa

Kiyotaka Fukino

Tsutomu Sugisaki

Shinji Tsujimoto

Nobuyoshi Asada

Kunihiko Honda

Masatoshi Kiyama

Kideaki Kosha

Koyotaka Fukino

Yoichi Hayata

Jun-ichi Nakamikawa

A method for reproducing information recorded on a magnetic recording medium comprising, in the following order, a non-magnetic flexible support, a non-magnetic lower layer containing non-magnetic powder and a binder, and a magnetic layer containing ferromagnetic powder, a binder and an abrasive, the magnetic layer having an average thickness of 30 to 150 nm, a density of projections having a height of 10 nm or more of 2,000 to 10,000 per 100 &#x3bc;mas measured by atomic force microscopy, and a scratch depth of 50 to 200 nm, the method comprising reading the magnetic recording medium with a magnetoresistive head having a magnetoresistive element, the magnetoresistive element being recessed 20 nm or less from a plane of contact with the magnetic recording medium.

Magnetic reproducing method and magnetic recording medium

A magnetic recording tape comprising a magnetic layer, a flexible support and a back coat layer in this order, wherein the support is a polyester film 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 back coat layer has protrusions having a height of 100 nm or more measured with an atomic force microscope in a density of from 10 to 500 in 90 &#x3bc;m square, and a ratio of a total number of protrusions having a height of 50 nm or more on the surface of the back coat layer to a total number of protrusions having a height of 100 nm or more on the surface of the back coat layer is from 10 to 100.

Magnetic recording tape

A leader tape comprising a support and a coating layer containing a powder and a binder, wherein at least one surface of the leader tape has a center line average roughness (Ra) of from 10 to 60 nm, and the leader tape has a cupping of from 0 to 1 mm per a width of &#xbd; inch.

Leader tape and magnetic tape cartridge using the same

A magnetic recording medium having a magnetic layer containing magnetic powder provided on a support is disclosed. The magnetic layer possesses a servo band in which a servo signal for controlling tracking of a magnetic head, and a data band on which a data is recorded. The servo signal is magnetized and recorded on the servo band, having been magnetized in one direction of the track direction thereof, in the direction other than the one direction. The thickness of the magnetic layer ranging from 10 to 180 &#x3bc;m, and variation [standard deviation of Mrt] of the product [Mrt] of the residual magnetism by the thickness of the magnetic field being not more than 30%.

Magnetic recording medium including servo and data bands in the magnetic layer

A magnetic recording and reproducing system, including recording a signal on a magnetic recording medium by an inductive head and reproducing the signal by a magneto resistance head. The gap length of the inductive head is 0.3 &#x3bc;m or less. The maximum particle diameter of ferromagnetic powder is from 1/10  to &#xbd; of the gap length, the minimum particle diameter of the powder is from 1/100 to &#x2155; of the gap length, and the thickness of a magnetic layer is from 1/10 to &#xbd; of the gap length. The average particle size of the powder is from 10 to 35 nm, the tabular ratio is from 2 to 6, the squareness ratio of in-plane of the magnetic layer is from 0.5 to 0.9 in the longitudinal direction, and from 0.2 to 0.6 in the thickness direction, and the thickness of the magnetic layer is from 0.01 to 0.2 &#x3bc;m.

Magnetic recording and reproducing system and magnetic recording medium used therein

Provided is a particulate magnetic recording medium having good durability and a high C/N ratio in high-density magnetic recording (particularly when employing an MR head for reproduction). A magnetic recording medium which comprises a lower layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder, an abrasive and a binder provided in this order on a nonmagnetic flexible support. The magnetic layer has a mean thickness d ranging from 0.01 to 0.1 &#x3bc;m, the ferromagnetic powder contained in the magnetic layer is an acicular ferromagnetic alloy powder having the mean major axis length equal to or less than 0.1 &#x3bc;m and the saturation magnetization &#x3c3;s equal to or less than 120 A&#xb7;m/kg, and the number of abrasive protrusions ranging in height from 5 to 10 nm on the surface of the magnetic layer ranges from 15 to 25/225 &#x3bc;m.

Magnetic recording medium

A magnetic tape is disclosed, comprising a support having thereon a magnetic layer comprising ferromagnetic particles and a binder as the main components, (i) the magnetic tape being for use in a magnetic recording/reproducing system in which signals recorded are reproduced with a magneto resistive head, (ii) the ferromagnetic particles contained in the magnetic layer being hexagonal-ferrite magnetic particles having an average tabular diameter of from 10 to 40 nm, and the magnetic layer having a machine direction coercive force Hof from 158 to 350 kA/m, a squareness ratio SQ&#x22a5; as measured in the direction perpendicular to the magnetic plane of 0.5 or lower, and a thickness of from 30 to 300 nm.

Magnetic tape

Provided is a magnetic recording medium which has excellent electromagnetic characteristics in an MR head and which is suited to high-density digital recording, especially suited to reproduction in an MR head. The magnetic recording medium comprises a magnetic layer comprising a ferromagnetic powder and a binder on a nonmagnetic support. The magnetic layer has a residual magnetization &PHgr;r ranging from 5 to 50 mA, and ratio (Sdc/Sac) of average area Sdc of magnetic clusters under DC magnetized condition to average area Sac of magnetic clusters under AC erased condition ranges from 0.8 to 2.0.

A magnetic recording tape comprising a magnetic layer, a flexible support and a backcoating layer in this order, wherein the backcoating layer has on its surface 10 to 200 projections having a height of 50 to 100 nm per 90 &mgr;m side square as measured with an atomic force microscope and 10 or fewer projections having a height greater than 100 nm and not greater than 500 nm per 90 &mgr;m side square as measured with an atomic force microscope, and the tape has a cupping of 3 to 20% of the tape width with convexity on the magnetic layer side.

A magnetic recording tape comprising a magnetic layer, a flexible support and a backcoating layer in this order, wherein the backcoating layer has on its surface 10 to 200 projections having a height of 50 to 100 nm per 90 &mgr;m side square as measured with an atomic force microscope and 10 or fewer projections having a height greater than 100 nm and not greater than 500 nm per 90 &mgr;m side square as measured with an atomic force microscope, and the tape has a curvature of 3 to 30% of the tape width per meter.

Provided is a magnetic recording medium exhibiting high C/N ratio and suited to high-density magnetic recording, particularly, to reproduction with MR heads. The magnetic recording medium comprises a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a flexible nonmagnetic support. The magnetic layer has an average thickness ranging from 0.02 to 0.2 &mgr;m, the ferromagnetic powder contained in the magnetic layer is a plate-shaped hexagonal ferrite ferromagnetic powder having an average plate diameter of 10 to 40 nm, the ratio of a volume of magnetic reversal to a volume of magnetic material particles is equal to or less than 3, the magnetic layer has a coercive force Hc equal to or higher than 159 kA/m, and components magnetically reversing in the magnetic field of 80 kA/m or less are less than 1 percent in the magnetization distribution of the magnetic layer.

A method of magnetic recording/reproducing is disclosed, which comprises reproducing with a magnetoresistive head (MR head) signals recorded in a magnetic recording medium comprising a support having thereon a magnetic layer comprising mainly ferromagnetic particles and a binder, wherein the MR head has an element thickness of 50 nm or smaller and the ferromagnetic particles are hexagonal-ferrite magnetic particles having an average tabular diameter of from 10 to 40 nm and an average tabular thickness smaller than the element thickness of the MR head used for reproduction.

Method of magnetic recording/reproducing

Magnetic tape recording medium, magnetic tape recording and reproducing apparatus, magnetic tape recording method and magnetic tape cassette

A magnetic recording medium having on a support at least two magnetic layers that include an uppermost magnetic layer for recording information and a lower magnetic layer for recording servo signals, wherein the uppermost magnetic layer has a coercive force Hc(U) &lsqb;KA/m&rsqb; at most 265 times as much as a saturated magnetic flux density Bs&lsqb;T&rsqb; of a recording head used for information recording and the lower magnetic layer has a coercive force Hc(L) &lsqb;KA/m&rsqb; at least 159 times as much as the saturated magnetic flux density Bs&lsqb;T&rsqb; of the recording head used for information recording, thereby ensuring highly accurate servo write and elevation of recording density.

Magnetic recording medium comprising magnetic layers, the coercive force thereof specifically related to saturation magnetic flux density

A magnetic recording medium is disclosed, comprising a support having thereon a magnetic layer which mainly comprises a ferromagnetic powder and a binder, wherein the magnetic recording medium is used in a magnetic recording reproduction system in which a recording signal is reproduced with a magnetic resistance type head (MR head), the ferromagnetic powder is a hexagonal magnetic ferrite powder having an average tabular diameter of from 10 to 40 nm, and the magnetic layer has a coercive force of 159 kA/m or more and has at most less than 1% of a component which performs magnetic flux revolution in a region of 80 kA/m or less in a differential curve of a remanence curve.

Growing community of inventors

Kanagawa, Japan

Kiyomi Ejiri