Sony Corporation

Sony Group Corporation

Minoru Yamaga

Masaru Terakawa

Noboru Sekiguchi

Takanobu Iwama

Eiji Nakashio

Jun Takahashi

Katsunori Maeshima

Yoichi Kanemaki

Naohiro Adachi

Kazuo Anno

Shinya Tochikubo

Tooru Sato

Masayoshi Abe

Kazuya Hashimoto

Futoshi Sasaki

Takashi Aizawa

Tomoe Sato

Jun Hashimoto

Kanako Hashimoto

Nobuyuki Sasaki

Takahiro Takayama

Yuuko Kamoshita

Hiroyuki Kobayashi

Takeshi Takahashi

Hiroshi Morita

Munetake Ebihara

Satoshi Sato

Noriyuki Hirai

Atsushi Muramatsu

Takahiro Miyazaki

Takashi Kataguchi

Natsuki Ichise

Hikaru Terui

Masafumi Nakaya

Toshiaki Miura

Yuji Iwahashi

Yuta Akimoto

Wataru Okawa

Tadahiro Abe

Tsutomu Ogawa

Yuuichi Masuzawa

Taikei Enomoto

A magnetic recording medium sequentially includes a base, an underlayer, and a magnetic layer. The magnetic layer includes magnetic particles, conductive first particles, and second particles having a Mohs hardness of 7.0 or more. The magnetic layer has a concavoconvex shape on a magnetic surface, and the concavoconvex shape includes a first protrusion including the first particles and a second protrusion including the second particles. A ratio H1/H2 of an average height H1 of the first protrusion and an average height H2 of the second protrusion satisfies H1/H2≤2.3, a height range ΔH obtained from statistical information on a height of the concavoconvex shape satisfies 3.00 nm≤ΔH≤6.00 nm, and a gradient range ΔA obtained from statistical information on a gradient of the concavoconvex shape satisfies 4.00 degrees≤ΔA≤9.00 degrees.

Magnetic recording medium and cartridge

A magnetic recording medium is a tape-shaped magnetic recording medium and includes: a base; and a magnetic layer. An average thickness of the magnetic recording medium is 5.30 μm or less. The magnetic layer contains a chlorine atom and a nitrogen atom, an atomic concentration ratio (A2/A1) of a maximum chlorine atomic concentration A1 obtained by measuring a chlorine atomic concentration of the magnetic layer in a thickness direction of the magnetic layer and a maximum nitrogen atomic concentration A2 obtained by measuring a nitrogen atomic concentration of the magnetic layer in the thickness direction of the magnetic layer is 0.50 or more and 0.75 or less. An average value of a protruding peak height Rpk of a surface of the magnetic layer is 2.10 nm or less.

Provided is a magnetic recording medium capable of curbing deterioration in electromagnetic conversion characteristics. A magnetic recording medium with a tape shape includes a substrate that contains polyesters, an underlayer that is provided on the substrate, and a magnetic layer that is provided on the underlayer and contains a magnetic powder. The magnetic recording medium contains a lubricant. An average value of arithmetic average roughnesses Ra of a surface of the magnetic layer is 1.3 nm or less. In a case where an average value of peak half widths of a spacing increase region generated on an entrance side of a glass pseudo head which the magnetic recording medium enters when the magnetic recording medium is slid over the glass pseudo head is set as a spacing index SRL and an average value of peak half widths of a spacing increase region generated in the vicinity of an edge of the magnetic recording medium in a width direction when the magnetic recording medium is slid over the glass pseudo head is set as a spacing index SRT, the spacing index SRL is 35 μm or less and the spacing index SRT is 68 μm or less.

Provided is a magnetic recording medium including: a support body; a base layer containing carbon particle powder and metal-containing particle powder; and a recording layer. In a recording surface, a maximum indentation depth h is 85≤h≤140, and a ratio d of a permanent strain to an elastic recovery (permanent strain/elastic recovery) is 0.95≤d≤1.25.

Magnetic recording medium

A magnetic recording cartridge is provided and includes a magnetic recording medium having a base layer; and a reel, in which a loss modulus at 65° C. of the base layer is 0.40 GPa or less, the magnetic recording medium is wound around the reel, and when a variation in width is measured over an entire length of the magnetic recording medium after storage at 65° C. for 360 hours, a sign of variation in width Δout on an outer side of winding is different from a sign of variation in width Δin on an inner side of winding, and the variation in width is 0 ppm at any position of two portions sandwiching a center line of the entire length of the magnetic recording medium in a case where the entire length of the magnetic recording medium is divided into four portions by dividing into four equal parts.

Magnetic recording cartridge including magnetic recording medium having a variation in width

A magnetic recording medium is provided and including a magnetic layer containing magnetic powders, in which, the magnetic layer contains first particles having conductivity and second particles of which Mohs hardness is 7 or more, protrusions are formed on a surface of the magnetic layer side in accordance with the first particles and the second particles, a ratio (H/H) of an average height (H) of protrusions formed in accordance with the first particles to an average height (H) of protrusions formed in accordance with the second particles is 2.3 or less, and the average height (H) of the protrusions formed in accordance with the second particles is 7 nm or less.

Provided is a cartridge capable of curbing charging of a magnetic tape even in a case where a drive gear is configured of an insulating resin. The cartridge includes a reel that has conductivity and includes a bottom wall, a magnetic tape that is wound around the reel, and a conductive member that is in contact with the reel, the conductive member having a reel gear on a lower surface of the bottom wall.

Cartridge including magnetic tape including magnetic layer including protrusions on surface thereof

Provided is a magnetic recording medium configured to achieve higher density recording. The magnetic recording medium has a tape-like shape, and includes: a base containing polyester as a main constituent; and a magnetic layer provided on the base, including a plurality of magnetic powders, and configured to record a data signal. An average thickness of the magnetic recording medium is 5.6 μm or less. An average thickness of the base is 4.2 μm or less. An average thickness of the magnetic layer is 90 nm or less. An average aspect ratio of the magnetic powders is 1.0 or greater and 3.0 or less. A coercivity in a perpendicular direction is 3000 oersted or less. A rate of a coercivity in a longitudinal direction to the coercivity in the perpendicular direction is 0.8 or less. The magnetic layer includes a lubricant. An entire BET specific surface area of the magnetic recording medium from which the lubricant has been removed is 2.5 m/g or greater.

Magnetic recording medium having a particular specific surface area, magnetic recording and reproducing apparatus, and magnetic recording medium cartridge

A magnetic recording medium is a magnetic recording medium having a tape shape and includes a substrate, an underlayer provided on the substrate, and a magnetic layer provided on the underlayer. The magnetic layer has a surface having an uneven shape, a height range ΔH obtained from statistical information of a height of the uneven shape is in a range of 4.00 nm≤ΔH≤10.00 nm, and a gradient range ΔA obtained from statistical information of a gradient of the uneven shape is in a range of 2.50 degrees≤ΔA.

Provided is a magnetic recording medium with a tape shape capable of correcting a change in width of the magnetic recording medium by adjusting a running tension of the magnetic recording medium in a case where the magnetic recording medium is saved or caused to run in a high-temperature environment. The magnetic recording medium is a magnetic recording medium with a tape shape, an amount of change in average width of the magnetic recording medium before and after the magnetic recording medium is left still for 40 hours in an environment at a temperature of 50° C. and a relative humidity of 40% RH in a state where a tension of 0.55 N is applied in a longitudinal direction is 170 ppm or less, and an average tension responsiveness with respect to a tension in the longitudinal direction in the environment at a temperature of 50° C. and a relative humidity of 40% RH is 700 ppm/N or more.

Magnetic recording medium having controlled change in average width and cartridge

A servo pattern recording method includes: determining a first servo band group that includes three or more servo bands for recording a servo pattern in which first servo band identification information having a plurality of bits is to be embedded, and a second servo band group that includes three or more servo bands for recording a servo pattern in which second servo band identification information having a plurality of bits is to be embedded, the second servo band identification information being different from the first servo band identification information; and recording the first and second servo band identification information on the first and second servo band groups, respectively, such that a combination of a first pair and a second pair is not duplicated, the first pair being a pair of servo band identification information and a phase in one servo band read by a first servo read head, the second pair being a pair of servo band identification information and a phase in the other servo band read by a second servo read head.

Servo pattern recording method, servo pattern recording apparatus, method of producing tape-like magnetic recording medium, tape-like magnetic recording medium, and servo write head

A magnetic recording medium is a tape-shaped magnetic recording medium, including: a substrate; an underlayer provided on the substrate; and a magnetic layer provided on the underlayer. The substrate contains polyester, each of the underlayer and the magnetic layer contains a lubricant, the magnetic layer has a surface on which a large number of holes is provided, the arithmetic average roughness Ra of the surface is 2.5 nm or less, a BET specific surface area of the entire magnetic recording medium measured in a state where the magnetic recording medium has been washed and dried is 3.5 m/g or more and 7.0 m/g or less, a squareness ratio of the magnetic layer in a vertical direction is 65% or more, an average thickness of the magnetic layer is 80 nm or less, an average thickness of the magnetic recording medium is 5.6 μm or less, and a servo pattern is recorded on the magnetic layer and a statistical value σindicating a non-linearity of the servo pattern is 24 nm or less.

A magnetic recording medium is a tape-shaped magnetic recording medium that has a recording layer including an ε-iron oxide particle. An area ratio R(=(S/S)×100) of a total area Sof an SFD curve of the recording layer in a perpendicular direction and an area Sof the SFD curve in which a coercivity Hc is in a range from −500 [Oe]≤Hc≤500 [Oe] is equal to or less than 5.5%.

A magnetic recording medium is a magnetic recording medium in the form of a tape and includes a substrate, a foundation layer provided on the substrate, and a magnetic layer provided on the foundation layer and containing a magnetic powder. The foundation layer and the magnetic layer each contain a lubricant. A squareness ratio of the magnetic layer in a perpendicular direction is equal to or higher than 65%, an average thickness of the magnetic recording medium is equal to or smaller than 5.6 μm, a plurality of recessed portions each having a depth corresponding to 20% or higher of the average thickness of the magnetic layer is provided on a surface of the magnetic layer, and the number of the recessed portions per unit area of 1,600 μmof the surface of the magnetic layer is equal to or greater than 20 and equal to or smaller than 200, and an amount of exudation of the lubricant per unit region of 12.5 μm×9.3 μm on the surface of the magnetic layer in a vacuum is equal to or greater than 3.0 μmand equal to or smaller than 6.5 μm.

A magnetic recording medium is a magnetic recording medium having a tape shape and includes a substrate, an underlayer provided on the substrate, and a magnetic layer provided on the underlayer. The magnetic layer has a surface having an uneven shape, a height range ΔH obtained from statistical information of a height of the uneven shape is in a range of 4.00 nm≤ΔH≤10.00 nm, and a gradient range ΔA obtained from statistical information of a gradient of the uneven shape is in a range of 2.50 degrees ≤ΔA.

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Miyagi, Japan

Minoru Yamaga