US-12626721-B2 - Magnetic tape, magnetic tape cartridge, servo pattern recording device, magnetic tape drive, magnetic tape system, detection device, inspection device, servo pattern recording method, manufacturing method of magnetic tape, detection method, and inspection method

Abstract

A first servo pattern has a first position and a second position which intersect an imaginary line. A second servo pattern has a third position intersecting the imaginary line. The imaginary line is set at a position at which a relationship in which a distance between the first position and the second position is half of a distance between the first position and the third position is established between the first servo pattern and the second servo pattern adjacent to each other in a longitudinal direction. A width of a servo band is set to a length in which a distance from the imaginary line to one end of the servo band in a width direction and a distance from the imaginary line to the other end of the servo band in the width direction are equal.

Inventors

• Toru Nakao
• Hodaka SUZUKI
• Yoichi AKANO

Assignees

• FUJIFILM CORPORATION

Dates

Publication Date

20260512

Application Date

20250404

Priority Date

20221014

Claims (20)

1. 1 . A magnetic tape comprising: a servo band, wherein a plurality of servo patterns are recorded in the servo band along a longitudinal direction of the magnetic tape, the servo pattern is at least one linear magnetization region pair, the linear magnetization region pair is a first linear magnetization region, which is linearly magnetized, and a second linear magnetization region, which is linearly magnetized, the first linear magnetization region and the second linear magnetization region are inclined in opposite directions with respect to a first imaginary straight line along a width direction of the magnetic tape, the first linear magnetization region has a steeper inclined angle with respect to the first imaginary straight line than the second linear magnetization region, positions of both ends of the first linear magnetization region and positions of both ends of the second linear magnetization region are aligned in the width direction of the magnetic tape, a first servo pattern and a second servo pattern are alternately disposed in the servo band along the longitudinal direction as the plurality of servo patterns, an imaginary line crossing the plurality of servo patterns along the longitudinal direction is set in the plurality of servo patterns, the first servo pattern has a first position and a second position which intersect the imaginary line, the second servo pattern has a third position intersecting the imaginary line, the first position is a position at which the imaginary line and the first linear magnetization region of the first servo pattern intersect each other, the second position is a position at which the imaginary line and the second linear magnetization region of the first servo pattern intersect each other, the third position is a position at which the imaginary line and the first linear magnetization region of the second servo pattern intersect each other, the imaginary line is set at a position at which a relationship in which a first distance, which is a distance between the first position and the second position, is half of a second distance, which is a distance between the first position and the third position, is established between the first servo pattern and the second servo pattern adjacent to each other in the longitudinal direction, and a width of the servo band is set to a length in which a distance from the imaginary line to one end of the servo band in the width direction and a distance from the imaginary line to the other end of the servo band in the width direction are equal.
2. 2 . The magnetic tape according to claim 1 , wherein the first linear magnetization region is a set of a plurality of first magnetization straight lines, the second linear magnetization region is a set of a plurality of second magnetization straight lines, the first position is a position at which a first magnetization straight line positioned at one end on the imaginary line in the longitudinal direction among the plurality of first magnetization straight lines included in the first servo pattern and the imaginary line intersect each other, the second position is a position at which a second magnetization straight line positioned at the one end on the imaginary line in the longitudinal direction among the plurality of second magnetization straight lines included in the first servo pattern and the imaginary line intersect each other, and the third position is a position at which a first magnetization straight line positioned at the one end on the imaginary line in the longitudinal direction among the plurality of first magnetization straight lines included in the second servo pattern and the imaginary line intersect each other.
3. 3 . The magnetic tape according to claim 2 , wherein the number of the first magnetization straight lines and the number of the second magnetization straight lines are the same in the servo pattern, the number of the first magnetization straight lines is different between the first servo pattern and the second servo pattern, and the number of the second magnetization straight lines is different between the first servo pattern and the second servo pattern.
4. 4 . The magnetic tape according to claim 1 , wherein a plurality of the servo bands are formed at a predetermined pitch in the width direction.
5. 5 . A magnetic tape cartridge comprising: the magnetic tape according to claim 1 ; and a case in which the magnetic tape is accommodated.
6. 6 . A magnetic tape drive comprising: a travel mechanism that causes the magnetic tape according to claim 1 to travel along a predetermined path; and a magnetic head including a plurality of servo reading elements that read the servo patterns on the predetermined path in a state in which the magnetic tape is caused to travel by the travel mechanism, wherein the plurality of servo reading elements are arranged along a longitudinal direction of the magnetic head, and the magnetic head is disposed in a posture in which the longitudinal direction of the magnetic head is inclined with respect to a traveling direction of the magnetic tape.
7. 7 . A magnetic tape system comprising: the magnetic tape according to claim 1 ; and a magnetic tape drive on which a magnetic head including a plurality of servo reading elements that read the servo patterns on a predetermined path in a state in which the magnetic tape is caused to travel along the predetermined path is mounted, wherein the plurality of servo reading elements are arranged along a longitudinal direction of the magnetic head, and the magnetic head is disposed in a posture in which the longitudinal direction of the magnetic head is inclined with respect to a traveling direction of the magnetic tape.
8. 8 . A detection device comprising: a processor, wherein the processor is configured to detect a servo signal, which is a result of the servo pattern being read from the magnetic tape according to claim 1 via a servo reading element, by using an autocorrelation coefficient.
9. 9 . An inspection device comprising: the detection device according to claim 8 ; and an inspection processor that performs an inspection of a servo band in which the servo pattern is recorded in the magnetic tape, based on the servo signal detected by the detection device.
10. 10 . A detection method comprising: detecting a servo signal, which is a result of the servo pattern being read from the magnetic tape according to claim 1 via a servo reading element, by using an autocorrelation coefficient.
11. 11 . An inspection method comprising: performing an inspection of a servo band in which the servo pattern is recorded in the magnetic tape based on the servo signal detected by the detection method according to claim 10 .
12. 12 . A servo pattern recording device comprising: a pulse signal generator; and a servo pattern recording head, wherein the pulse signal generator generates a pulse signal, the servo pattern recording head has a gap pattern, and records a plurality of servo patterns in a band-shaped region, which is formed in a band shape on a front surface of a magnetic tape along a longitudinal direction of the magnetic tape, along the longitudinal direction by applying a magnetic field to the band-shaped region from the gap pattern in response to the pulse signal, a servo band is formed by the plurality of servo patterns being recorded in the band-shaped region along the longitudinal direction, the gap pattern is at least one straight line region pair, a first straight line region, which is one straight line region of the straight line region pair, and a second straight line region, which is the other straight line region of the straight line region pair, are inclined in opposite directions with respect to a second imaginary straight line on the front surface along a direction corresponding to a width direction of the magnetic tape, the first straight line region has a steeper inclined angle with respect to the second imaginary straight line than the second straight line region, positions of both ends of the first straight line region and positions of both ends of the second straight line region are aligned in the direction corresponding to the width direction of the magnetic tape, the servo pattern is at least one linear magnetization region pair, the linear magnetization region pair is a first linear magnetization region, which is linearly magnetized, and a second linear magnetization region, which is linearly magnetized, the first linear magnetization region and the second linear magnetization region are inclined in opposite directions with respect to a first imaginary straight line along the width direction of the magnetic tape, the first linear magnetization region has a steeper inclined angle with respect to the first imaginary straight line than the second linear magnetization region, positions of both ends of the first linear magnetization region and positions of both ends of the second linear magnetization region are aligned in the width direction of the magnetic tape, a first servo pattern and a second servo pattern are alternately disposed in the servo band along the longitudinal direction as the plurality of servo patterns, an imaginary line crossing the plurality of servo patterns along the longitudinal direction is set in the plurality of servo patterns, the first servo pattern has a first position and a second position which intersect the imaginary line, the second servo pattern has a third position intersecting the imaginary line, the first position is a position at which the imaginary line and the first linear magnetization region of the first servo pattern intersect each other, the second position is a position at which the imaginary line and the second linear magnetization region of the first servo pattern intersect each other, the third position is a position at which the imaginary line and the first linear magnetization region of the second servo pattern intersect each other, the imaginary line is set at a position at which a relationship in which a first distance, which is a distance between the first position and the second position, is half of a second distance, which is a distance between the first position and the third position, is established between the first servo pattern and the second servo pattern adjacent to each other in the longitudinal direction, and a width of the servo band is set to a length in which a distance from the imaginary line to one end of the servo band in the width direction and a distance from the imaginary line to the other end of the servo band in the width direction are equal.
13. 13 . The servo pattern recording device according to claim 12 , wherein the first linear magnetization region is a set of a plurality of first magnetization straight lines, the second linear magnetization region is a set of a plurality of second magnetization straight lines, the first position is a position at which a first magnetization straight line positioned at one end on the imaginary line in the longitudinal direction among the plurality of first magnetization straight lines included in the first servo pattern and the imaginary line intersect each other, the second position is a position at which a second magnetization straight line positioned at the one end on the imaginary line in the longitudinal direction among the plurality of second magnetization straight lines included in the first servo pattern and the imaginary line intersect each other, and the third position is a position at which a first magnetization straight line positioned at the one end on the imaginary line in the longitudinal direction among the plurality of first magnetization straight lines included in the second servo pattern and the imaginary line intersect each other.
14. 14 . The servo pattern recording device according to claim 13 , wherein the number of the first magnetization straight lines and the number of the second magnetization straight lines are the same in the servo pattern, the number of the first magnetization straight lines is different between the first servo pattern and the second servo pattern, and the number of the second magnetization straight lines is different between the first servo pattern and the second servo pattern.
15. 15 . The servo pattern recording device according to claim 12 , wherein a plurality of the servo bands are formed at a predetermined pitch in the width direction.
16. 16 . A magnetic tape in which the plurality of servo patterns are recorded by the servo pattern recording device according to claim 12 .
17. 17 . A magnetic tape cartridge comprising: the magnetic tape according to claim 16 ; and a case in which the magnetic tape is accommodated.
18. 18 . A magnetic tape drive comprising: a travel mechanism that causes the magnetic tape according to claim 16 to travel along a predetermined path; and a magnetic head including a plurality of servo reading elements that read the servo patterns on the predetermined path in a state in which the magnetic tape is caused to travel by the travel mechanism, wherein the plurality of servo reading elements are arranged along a longitudinal direction of the magnetic head, and the magnetic head is disposed in a posture in which the longitudinal direction of the magnetic head is inclined with respect to a traveling direction of the magnetic tape.
19. 19 . A magnetic tape system comprising: the magnetic tape according to claim 16 ; and a magnetic tape drive on which a magnetic head including a plurality of servo reading elements that read the servo patterns on a predetermined path in a state in which the magnetic tape is caused to travel along the predetermined path is mounted, wherein the plurality of servo reading elements are arranged along a longitudinal direction of the magnetic head, and the magnetic head is disposed in a posture in which the longitudinal direction of the magnetic head is inclined with respect to a traveling direction of the magnetic tape.
20. 20 . A detection device comprising: a processor, wherein the processor is configured to detect a servo signal, which is a result of the servo pattern being read from the magnetic tape according to claim 16 via a servo reading element, by using an autocorrelation coefficient.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation application of International Application No. PCT/JP2023/036433, filed Oct. 5, 2023, the disclosure of which is incorporated herein by reference in its entirety. Further, this application claims priority from Japanese Patent Application No. 2022-165743, filed Oct. 14, 2022, the disclosure of which is incorporated herein by reference in its entirety. BACKGROUND 1. Technical Field The technology of the present disclosure relates to a magnetic tape, a magnetic tape cartridge, a servo pattern recording device, a magnetic tape drive, a magnetic tape system, a detection device, an inspection device, a servo pattern recording method, a manufacturing method of a magnetic tape, a detection method, and an inspection method. 2. Related Art In US2021/0125633A, a servo pattern on a magnetic tape performs compensation in a width direction by inclining a head of a magnetic tape drive using the same pattern as in the related art. The same pattern as in the related art refers to a pattern in which two non-parallel patterns are symmetrically disposed with respect to an imaginary line in the width direction and have the same azimuth angle and backward directions. In the servo pattern disclosed in US2021/0125633A, non-uniformity of a servo signal occurs. In order to solve this problem, a servo pattern disclosed in US2022/0108718A is formed in an orientation in which the symmetrically disposed servo patterns of the related art are rotated, and thus, non-uniformity of a servo signal is suppressed. SUMMARY One embodiment according to the technology of the present disclosure is to provide a magnetic tape, a magnetic tape cartridge, a servo pattern recording device, a magnetic tape drive, a magnetic tape system, a detection device, an inspection device, a servo pattern recording method, a manufacturing method of a magnetic tape, a detection method, and an inspection method, which are capable of contributing to realization of highly accurate reading of a servo band. A first aspect according to the technology of the present disclosure relates to a magnetic tape comprising: a servo band, in which a plurality of servo patterns are recorded in the servo band along a longitudinal direction of the magnetic tape, the servo pattern is at least one linear magnetization region pair, the linear magnetization region pair is a first linear magnetization region, which is linearly magnetized, and a second linear magnetization region, which is linearly magnetized, the first linear magnetization region and the second linear magnetization region are inclined in opposite directions with respect to a first imaginary straight line along a width direction of the magnetic tape, the first linear magnetization region has a steeper inclined angle with respect to the first imaginary straight line than the second linear magnetization region, positions of both ends of the first linear magnetization region and positions of both ends of the second linear magnetization region are aligned in the width direction of the magnetic tape, a first servo pattern and a second servo pattern are alternately disposed in the servo band along the longitudinal direction as the plurality of servo patterns, an imaginary line crossing the plurality of servo patterns along the longitudinal direction is set in the plurality of servo patterns, the first servo pattern has a first position and a second position which intersect the imaginary line, the second servo pattern has a third position intersecting the imaginary line, the first position is a position at which the imaginary line and the first linear magnetization region of the first servo pattern intersect each other, the second position is a position at which the imaginary line and the second linear magnetization region of the first servo pattern intersect each other, the third position is a position at which the imaginary line and the first linear magnetization region of the second servo pattern intersect each other, the imaginary line is set at a position at which a relationship in which a first distance, which is a distance between the first position and the second position, is half of a second distance, which is a distance between the first position and the third position, is established between the first servo pattern and the second servo pattern adjacent to each other in the longitudinal direction, and a width of the servo band is set to a length in which a distance from the imaginary line to one end of the servo band in the width direction and a distance from the imaginary line to the other end of the servo band in the width direction are equal. A second aspect according to the technology of the present disclosure relates to the magnetic tape according to the first aspect, in which the first linear magnetization region is a set of a plurality of first magnetization straight lines, the second linear magnetization region is a set of a plurality of second