Hitachi Maxell, Limited

Tsugihiro Doi

Tetsutaro Inoue

Sadamu Kuse

Hiroyuki Mitsuhashi

Mikio Kishimoto

Seigi Kawarai

Masao Okafuji

Yuji Sasaki

Hideaki Watanabe

Akira Miyake

Teruo Sogabe

Ken Yoshimura

Akito Sakemoto

Kunio Mizushima

Hitoshi Nagatani

Minoru Ezoe

Akira Ohtani

The electrode of the present invention includes a current collector and an active material-containing layer formed on one side or both sides of the current collector. The active material-containing layer has a thickness of 20 to 200 &#x3bc;m per one side of the current collector, and diethyl carbonate permeates the active material-containing layer at a rate of 0.1 g/(cm&#xb7;min) or higher. Further, the method for producing an electrode of the present invention includes the steps of: forming an electrode precursor by forming an active material-containing layer on one side or both sides of a current collector; and compressing the electrode precursor. In the electrode precursor forming step, the active material-containing layer is formed such that the active material-containing layer has a higher porosity in a portion close to the current collector then in other portions.

Electrode and method for producing the same

In a recording/reproducing method of a magnetic tape in a tracking servo system, a recording density of each data track is increased while inhibiting occurrence of a recording/reproducing error caused by a size change of a magnetic tape in the width direction. Data tracks are each set to have a smaller track width stepwise as closer to servo tracks (T-toT-etc.) in the width direction of a magnetic tape. With such a setting, the width of the data tracks (A-T-to A-T-etc.) closest to the servo tracks (T-toT-) can be minimized, thereby enabling a significant increase in number of the data tracks. Further, even when the size of the magnetic tapechanges in the width direction due to a change in external environment such as a temperature or moisture, to lead to large displacement of the data tracks (A-T-to A-T-) distant from the servo tracks (T-toT-), the data head (A) can be readily aligned to face the data tracks (A-T-to A-T-) in the reproduction by an increased portion of the width size of the data tracks (A-T-to A-T-), and it is thereby possible to ensure reading of data signals from the data tracks (A-T-to A-T-) so as to improve reproduction accuracy.

Recording/reproducing method of magnetic tape

In a recording/reproducing method of a magnetic tape in a tracking servo system, a recording density of each data track is increased while inhibiting occurrence of a recording/reproducing error caused by a size change of a magnetic tape in the width direction. Data tracks are each set to have a smaller track width stepwise as closer to servo tracks (T-toT-etc.) in the width direction of a magnetic tapeWith such a setting, the width of the data tracks (A-T-to A-T-etc. ) closest to the servo tracks (T-toT-) can be minimized, thereby enabling a significant increase in number of the data tracks. Further, even when the size of the magnetic tapechanges in the width direction due to a change in external environment such as a temperature or moisture, to lead to large displacement of the data tracks (A-T-to A-T-) distant from the servo tracks (T-toT-), the data head (A) can be readily aligned to face the data tracks (A-T-to A-T-) in the reproduction by an increased portion of the width size of the data tracks (A-T-to A-T-), and it is thereby possible to ensure reading of data signals from the data tracks (A-T-to A-T-) so as to improve reproduction accuracy.

A recording medium built-in cartridge of the present invention includes: a case; a recording medium housed in the case; and at least one humidity control member disposed in the case and including at least one humidity control material that absorbs moisture in the case when a humidity in the case is a first humidity or higher and emits the moisture to the case when the humidity in the case is a second humidity or lower, the second humidity being lower than the first humidity.

Recording medium built-in cartridge and cartridge built-in package

A magnetic tape comprising a non-magnetic support, a magnetic layer containing magnetic powder which is formed on one side of the non-magnetic support, a primer layer containing non-magnetic powder which is formed between the non-magnetic support and the magnetic layer, and a backcoat layer containing non-magnetic powder which is formed on the other side of the non-magnetic support, wherein the magnetic layer contains the magnetic powder which comprises plate, granular or ellipsoidal magnetic particles with a particle diameter of 5 to 50 nm, and has a thickness of 0.09 &#x3bc;m or less, and wherein at least one of the primer layer and the backcoat layer contains non-magnetic plate particles with a particle diameter of 10 to 100 nm.

Magnetic tape and magnetic tape cartridge

A magnetic recording medium comprising a non-magnetic support, at least one primer layer formed on one surface of the non-magnetic support, comprising a non-magnetic powder and a binder resin, at least one magnetic layer formed on the primer layer, comprising a magnetic powder and a binder resin, and a back layer formed on the other surface of the non-magnetic support, wherein the magnetic powder contained in the uppermost layer of the magnetic layer is a rare earth metal-iron type magnetic powder of substantially spherical or ellipsoidal particles comprising a rare earth element and iron or a transition metal which comprises iron, and has a number average particle size of 5 to 50 nm and an average axis ratio of 1 to 2, and the total thickness of the magnetic recording medium is less than 6 &#x3bc;m. This magnetic recording medium can achieve an excellent block error rate.

Magnetic recording medium using magnetic powder having a core portion and an outer layer portion including a rare earth element and magnetic recording cassette

There is provided a magnetic tape cartridge, including a cartridge () composed of a top cartridge () and a bottom cartridge (), a reel () rotatably disposed in the cartridge (), and a magnetic tape () wound onto the reel (), in which a width (w) of the magnetic tape () is over 12.65 mm, a thickness (h) of the cartridge () is 32 mm or less, and the width (w) of the magnetic tape is 60% to 90% of the thickness (h) of the cartridge ().

Magnetic tape cartridge

A magnetic recording medium comprising a non-magnetic support, at least one primer layer formed on one surface of the non-magnetic support, comprising a non-magnetic powder and a binder resin, at least one magnetic layer formed on the primer layer, comprising a magnetic powder and a binder resin, and a back layer formed on the other surface of the non-magnetic support, wherein the magnetic powder contained in the uppermost layer of the magnetic layer is a rare earth metal-iron type magnetic powder of substantially spherical or ellipsoidal particles comprising a rare earth element and iron or a transition metal which comprises iron, and has a number average particle size 5 to 50 nm and an average axis ratio of 1 to 2, and the total thickness of the magnetic recording medium is less than 6 &#x3bc;m. This magnetic recording medium can achieve an excellent block error rate, which cannot be realized with magnetic recording media comprising conventional acicular magnetic powders.

A magnetic recording medium comprising a non-magnetic support; at least one lower magnetic layer containing magnetic powder and a binder resin, which is formed on one side of the non-magnetic support with or without a non-magnetic primer layer interposed between the non-magnetic support and the lower magnetic layer; at least one non-magnetic intermediate layer containing non-magnetic powder and a binder resin, which is formed on the lower magnetic layer; at least one upper magnetic layer containing magnetic powder and a binder resin, which is formed on the non-magnetic intermediate layer; and a back layer which is formed on the other side of the non-magnetic support, characterized in that the magnetic powder contained in the uppermost magnetic layer of the upper magnetic layer is iron type magnetic powder which comprises substantially spherical or ellipsoidal particles with a number-average particle diameter of 5 to 50 nm and an average axial ratio of 1 to 2, each of said particles containing iron or containing iron as a main component and a transition element; and that the total thickness of the magnetic recording medium is 6 &#x3bc;m or less. This magnetic recording medium has electromagnetic conversion characteristics which cannot be achieved by any of conventional magnetic recording media, and also is expected to have excellent magnetic serve characteristics.

A magnetic tape having a lower non-magnetic layer containing non-magnetic powder and a binder, and an upper magnetic layer containing ferromagnetic powder and a binder, formed on a surface of a tape-form non-magnetic support. This magnetic tape has an intermediate binder layer, which is under the upper magnetic layer and has an average dry thickness of 10 to less than 50 nm. The average dry thickness of the upper magnetic layer is 5 to 100 nm, and the squareness ratio of the upper magnetic layer in the lengthwise direction is 0.8 or more. In this magnetic tape, the thickness of the magnetic layer and the fluctuation at the interface between the magnetic layer and the intermediate binder layer under the magnetic layer can be controlled. As a result, the PW50 value of a solitary waveform and modulation noise can be reduced. Thus, the magnetic tape shows excellent C/N characteristics.

Magnetic tape including an intermediate layer consisting essentially of a binder

There is provided a magnetic tape, to be used at a running speed of at least 4,000 mm/sec., wherein servo signals for controlling tracking are recorded on the magnetic layer or the backcoat layer, and wherein the difference between the recording track width and the reproducing track width is 16 &#x3bc;m or less, characterized in that the value of [&#x3b1;/(Tw&#x2212;Tr)] is 0.2 or less, wherein a [&#x3bc;m] is an amount of a weave occurring on one of both edges of the magnetic tape and on the side of reference for the running of the tape; Tw [&#x3bc;m] is a recording track width; and Tr [&#x3bc;m] is a reproducing track width; and that a coefficient of humidity expansion in the tape widthwise direction is (0 to 14)&#xd7;10/% RH; and a coefficient of thermal expansion in the tape widthwise direction is (0 to 10)&#xd7;10/&#xb0; C. This magnetic tape has a recording track width of 28 &#x3bc;m or less, and is excellent in servo performance, since a decrease in reproduction output due to off-track hardly occurs even when the difference between the recording track width and the reproducing track width is 16 &#x3bc;m or less.

A magnetic recording medium comprising a non-magnetic substrate, a primer coating formed on the substrate and comprising an organic conducting polymer and a magnetic layer formed on the primer coating, which has good surface smoothness and low surface resistance.

Magnetic recording medium comprising a substrate coated with a primer

A magnetic disc which comprises a non-magnetic support substrate and a magnetic layer thereon consisting of a magnetic coating comprising ferromagnetic powder, a binder, an aliphatic acid ester having a melting point not higher than 10.degree. C. and an aliphatic acid ester having a melting point from 15.degree. to 60.degree. C., the magnetic coating having improved lubricity and durability.

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Ibaraki, Japan

Tsugihiro Doi