# US 12,087,337 B2 · Magnetic tape device comprising a characteristic magnetic head and a characteristic medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,087,337 B2 - Document ID: US12087337B2 - Status: Granted - Kind: B2 - Application number: 17/872,651 - Filed: 2022-07-25 - Published: 2023-02-09 - Granted: 2024-09-10 - Earliest claimed: 2021-07-26 - Assignees: FUJIFILM Corporation - Applicants: FUJIFILM Corporation - Inventors: Norihito Kasada - Web page: https://patentgrep.com/patent/US12087337B2 ## CPC - G11B 5/584: for track following on tapes - G11B 5/73927: {Polyester substrates, e.g. polyethylene terephthalate} - G11B 5/78: Tape carriers - G11B 5/127: Structure or manufacture of heads, e.g. inductive - G11B 5/739: {Magnetic recording media substrates} - 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 device. The angle θ formed by the axis of the element array of the magnetic head with respect to a width direction of the magnetic tape is changed during running of the magnetic tape in the magnetic tape device. In a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in a predetermined environment and a servo band spacing obtained after storage in the environment for a storage time T is defined as A, and T is set to a plurality of predetermined times, a medium life calculated by a linear function of A and a logarithm loge T of T, that are derived from a value of A and a value of the logarithm loge T of T obtained for each T is 5 years or longer. ## Claims ### Claim 1 A magnetic tape device comprising: a medium; and a magnetic head, wherein the medium is a magnetic tape, the magnetic head includes a module including an element array including a plurality of magnetic head elements between a pair of servo signal reading elements, the magnetic tape device changes an angle θ formed by an axis of the element array with respect to a width direction of the magnetic tape during running of the magnetic tape in the magnetic tape device, the magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder, the magnetic layer includes a plurality of servo bands, in a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in an environment of a temperature of 32° C. and relative humidity of 55% and a servo band spacing obtained after storage in the environment for a storage time T is defined as A, a unit of A is μm, and T is set to 24 hours, 48 hours, 72 hours, 96 hours, or 120 hours, a medium life calculated by a linear function of A and a logarithm loge T of T, that are derived from a value of A and a value of the logarithm loge T of T obtained for each T is 5 years or longer, the medium life is the storage time T when A satisfies Equation 1: A=1.5 −B+C, (Equation 1) the B is a value calculated by multiplying a difference between a maximum value and a minimum value of servo band spacings obtained in each of the following five environments of a temperature of 16° C. and relative humidity of 20%, a temperature of 16° C. and relative humidity of 80%, a temperature of 26° C. and relative humidity of 80%, a temperature of 32° C. and relative humidity of 20%, and a temperature of 32° C. and relative humidity of 55%, by ½, and a unit is μm, and the C is a value calculated by C=L{COS(θinitial−Δθ)−cos(θinitial−Δθ)} and a unit is μm, the L is a distance between the pair of servo signal reading elements and a unit is μm, and in a case where the angle θ at start of the running of the magnetic tape is defined as θinitial, a maximum value of the angle θ during the running of the magnetic tape is defined as θmax, and a minimum value thereof is defined as θmin, and the Δθ is a greater value between values calculated by Δθmax=θmax−θinitial and Δθmin=θinitial−θmin. ### Claim 2 (depends on 1) The magnetic tape device according to claim 1, wherein the medium life is 5 years to 300 years. ### Claim 3 (depends on 1) The magnetic tape device according to claim 1, wherein the angle θ formed by the axis of the element array with respect to the width direction of the magnetic tape during the running of the magnetic tape in the magnetic tape device is changed according to dimensional information of the magnetic tape in the width direction obtained during the running. ### Claim 4 (depends on 1) The magnetic tape device according to claim 1, wherein the magnetic tape further includes a non-magnetic layer including a non-magnetic powder between the non-magnetic support and the magnetic layer. ### Claim 5 (depends on 1) The magnetic tape device according to claim 1, wherein the magnetic tape further includes a back coating layer including a non-magnetic powder on a surface side of the non-magnetic support opposite to a surface side on which the magnetic layer is provided. ### Claim 6 (depends on 1) The magnetic tape device according to claim 1, wherein the non-magnetic support is an aromatic polyester support. ### Claim 7 (depends on 6) The magnetic tape device according to claim 6, wherein the aromatic polyester support is a polyethylene terephthalate support. ### Claim 8 (depends on 6) The magnetic tape device according to claim 6, wherein the aromatic polyester support is a polyethylene naphthalate support. ### Claim 9 (depends on 1) The magnetic tape device according to claim 1, wherein the non-magnetic support is an aromatic polyamide support. ### Claim 10 (depends on 1) The magnetic tape device according to claim 1, wherein a vertical squareness ratio of the magnetic tape is 0.60 or more. ### Claim 11 (depends on 2) The magnetic tape device according to claim 2, wherein a vertical squareness ratio of the magnetic tape is 0.60 or more.