# US 10,504,546 B2 · Magnetic tape having characterized magnetic particles and magnetic tape device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,504,546 B2 - Document ID: US10504546B2 - Status: Granted - Kind: B2 - Application number: 15/628,814 - Filed: 2017-06-21 - Published: 2017-12-28 - Granted: 2019-12-10 - Earliest claimed: 2016-06-23 - Assignees: FUJIFILM Corporation - Applicants: FUJIFILM Corporation - Inventors: Tetsuya Kaneko; Norihito Kasada; Eiki Ozawa - Web page: https://patentgrep.com/patent/US10504546B2 ## CPC - G11B 5/588: by controlling the position of the rotating heads (by controlling the speed of the record carrier G11B15/467; by controlling speed of the heads G11B15/473; {by moving the transducing part of the head relative to the headwheel, in the direction of the scanning movement G11B15/1841}) - G11B 5/584: for track following on tapes - G11B 5/70: on a base layer - G11B 5/70678: {Ferrites} - G11B 5/7085: {non-magnetic abrasive particles} - G11B 5/78: Tape carriers - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract A magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binder on the non-magnetic support. The total thickness of the magnetic tape is less than or equal to 5.30 μm. The magnetic layer includes a timing-based servo pattern. The center line average surface roughness Ra measured regarding the surface of the magnetic layer is less than or equal to 1.8 nm. The ferromagnetic powder is ferromagnetic hexagonal ferrite powder, and the magnetic layer includes an abrasive. Further, the tilt cos θ of the ferromagnetic hexagonal ferrite powder with respect to the surface of the magnetic layer acquired by cross section observation performed using a scanning transmission electron microscope is 0.85 to 1.00. ## Claims ### Claim 1 A magnetic tape comprising: a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binder on the non-magnetic support, wherein the total thickness of the magnetic tape is equal to or smaller than 5.30 μm, the magnetic layer includes a timing-based servo pattern, the center line average surface roughness Ra measured regarding the surface of the magnetic layer is equal to or smaller than 1.8 nm, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer includes an abrasive, the tilt cos θ of the ferromagnetic hexagonal ferrite powder with respect to the surface of the magnetic layer acquired by cross section observation performed by using a scanning transmission electron microscope is 0.85 to 1.00, and the percentage of hexagonal ferrite particles having a length in the long axis direction of equal to or greater than 10 nm and having an aspect ratio in a range of 1.5 to 6.0 in all of the hexagonal ferrite particles is equal to or greater than 50% but equal to or smaller than 95%, based on the particle number. ### Claim 2 (depends on 1) The magnetic tape according to claim 1, wherein the cos θ is 0.89 to 1.00. ### Claim 3 (depends on 1) The magnetic tape according to claim 1, wherein the magnetic layer further includes a polyester chain-containing compound having a weight-average molecular weight of 1,000 to 80,000. ### Claim 4 (depends on 1) The magnetic tape according to claim 1, wherein the activation volume of the ferromagnetic hexagonal ferrite powder is 800 nm3 to 2,500 nm3. ### Claim 5 (depends on 1) The magnetic tape according to claim 1, wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 1.8 nm. ### Claim 6 (depends on 1) The magnetic tape according to claim 1, wherein the total thickness of the magnetic tape is 3.00 μm to 5.30 μm. ### Claim 7 (depends on 1) The magnetic tape according to claim 1, further comprising: a non-magnetic layer including non-magnetic powder and a binder between the non-magnetic support and the magnetic layer. ### Claim 8 (depends on 1) The magnetic tape according to claim 1, further comprising: a back coating layer including non-magnetic powder and a binder on a side of the non-magnetic support opposite to a side where the magnetic layer is provided. ### Claim 9 (depends on 1) The magnetic tape according to claim 1, wherein the abrasive includes alumina powder. ### Claim 10 (depends on 1) The magnetic tape according to claim 1, wherein the cos θ is 0.85 to 0.98. ### Claim 11 A magnetic tape device comprising: a magnetic tape, a magnetic head; and a servo head, wherein the magnetic tape is a magnetic tape comprising: a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binder on the non-magnetic support, wherein the total thickness of the magnetic tape is equal to or smaller than 5.30 μm, the magnetic layer includes a timing-based servo pattern, the center line average surface roughness Ra measured regarding the surface of the magnetic layer is equal to or smaller than 1.8 nm, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer includes an abrasive, the tilt cos θ of the ferromagnetic hexagonal ferrite powder with respect to the surface of the magnetic layer acquired by cross section observation performed by using a scanning transmission electron microscope is 0.85 to 1.00, and the percentage of hexagonal ferrite particles having a length in the long axis direction of equal to or greater than 10 nm and having an aspect ratio in a range of 1.5 to 6.0 in all of the hexagonal ferrite particles is equal to or greater than 50% but equal to or smaller than 95%, based on the particle number. ### Claim 12 (depends on 11) The magnetic tape device according to claim 11, wherein the cos θ is 0.89 to 1.00. ### Claim 13 (depends on 11) The magnetic tape device according to claim 11, wherein the magnetic layer further includes a polyester chain-containing compound having a weight-average molecular weight of 1,000 to 80,000. ### Claim 14 (depends on 11) The magnetic tape device according to claim 11, wherein the activation volume of the ferromagnetic hexagonal ferrite powder is 800 nm3 to 2,500 nm3. ### Claim 15 (depends on 11) The magnetic tape device according to claim 11, wherein the center line average surface roughness Ra measured regarding the surface of the magnetic layer is 1.2 nm to 1.8 nm. ### Claim 16 (depends on 11) The magnetic tape device according to claim 11, wherein the total thickness of the magnetic tape is 3.00 μm to 5.30 μm. ### Claim 17 (depends on 11) The magnetic tape device according to claim 11, wherein the magnetic tape further comprises a non-magnetic layer including non-magnetic powder and a binder between the non-magnetic support and the magnetic layer. ### Claim 18 (depends on 11) The magnetic tape device according to claim 11, wherein the magnetic tape further comprises a back coating layer including non-magnetic powder and a binder on a side of the non-magnetic support opposite to a side where the magnetic layer is provided. ### Claim 19 (depends on 11) The magnetic tape device according to claim 11, wherein the abrasive includes alumina powder.