Magnetic tape, magnetic tape cartridge, magnetic tape system, inspection method, and manufacturing method for magnetic tape

Abstract

The index indicating the non-linearity of the servo pattern is controlled to be less than 15% of the track spacing. Track spacing is the distance between tracks. The index indicates the degree of dispersion of multiple distance differences from the average of multiple distance differences. The distance difference is the difference between the distance between a pair of corresponding first positions in the width direction of a pair of servo patterns and the distance between a pair of second positions in a pair of servo patterns offset from the pair of first positions in the width direction by a first predetermined interval. The multiple distance differences are obtained by measuring the distance differences every second predetermined interval along the width direction in a pair of servo patterns. The first predetermined interval is greater than the second predetermined interval.

Description

Technical Field

[0001] The technology disclosed herein relates to a magnetic tape, a magnetic tape cassette, a magnetic tape system, an inspection method, and a method for manufacturing a magnetic tape. Background Technology

[0002] Japanese Patent Application Publication No. 2022-057517 discloses a magnetic tape having a timing-based servo pattern and used in a magnetic tape device with a total number of data tracks of 8705 or more when converted to a 1 / 2-inch wide magnetic tape. The timing-based servo pattern has a ΔPNL of 10.0% or less of the track pitch, and ΔPNL represents the amount of linear offset from the timing-based servo pattern.

[0003] Japanese Patent Application Publication No. 2019-046521 discloses a recording device comprising a recording unit that records information relating to the linearity of a servo signal recorded on a magnetic tape in a recording tape cassette in a recording medium in the recording tape cassette.

[0004] In U.S. Patent Application Publication No. 2019 / 0279673, an shingled recording method is disclosed as a method of recording data on magnetic tape. Summary of the Invention

[0005] One embodiment of the technology disclosed herein provides a magnetic tape, a magnetic tape cassette, a magnetic tape system, an inspection method, and a method for manufacturing a magnetic tape, wherein the magnetic tape can help improve the accuracy of recording data on the magnetic tape and the accuracy of reproducing the data recorded on the magnetic tape.

[0006] means for solving technical problems The first method involved in the disclosed technology is a magnetic tape, which is a magnetic tape in which multiple servo tapes, each recording multiple servo patterns along the length direction, are arranged along the width direction. The index indicating the non-linearity of the servo patterns is controlled to be less than 15% of the track spacing. The track spacing is the distance between multiple tracks formed by recording data on the magnetic tape according to signals obtained from multiple servo patterns by recording elements. The index indicates the degree of dispersion of multiple PES difference gaps from the average value of multiple PES difference gaps. The PES difference gap is the difference between the first PES difference and the second PES difference. The first PES difference is the PES difference between a pair of corresponding first positions in a pair of servo patterns recorded in a pair of servo tapes that span more than one servo tape in the width direction, and the second PES difference is the PES difference between a pair of second positions in a pair of servo patterns that are offset from a pair of first positions in the width direction by a first predetermined interval in the width direction. The multiple PES difference gaps are obtained by measuring the PES difference gaps in a pair of servo patterns at every second predetermined interval along the width direction. The first predetermined interval is greater than the second predetermined interval.

[0007] The second method of the technology disclosed herein is the magnetic tape involved in the first method, wherein multiple tracks are formed by recording data onto the magnetic tape by a recording element in an SMR manner.

[0008] The third method of the technology disclosed herein is the magnetic tape involved in the first or second method, wherein the index is a value equivalent to three times the standard deviation of multiple PES difference gaps.

[0009] The fourth method of the technology disclosed herein refers to the magnetic tape involved in any of the first to third methods, wherein the first predetermined interval is the interval closest to the reference interval, which is a natural multiple of the second predetermined interval and is equivalent to half the difference between the length of the recording element as the length of the recording element in the width direction and the track spacing.

[0010] The fifth method of the technology disclosed herein refers to the magnetic tape involved in any of the first to third methods, wherein the first predetermined interval is an interval that is a natural multiple of 2 or more of the second predetermined interval.

[0011] The sixth method of the technology disclosed herein refers to the magnetic tape involved in any one of the methods 1 to 6, wherein the first predetermined interval is greater than the track spacing.

[0012] The seventh method involved in the technology disclosed herein is the magnetic tape involved in any of the methods 1 to 6, wherein the index is controlled to be less than 10% of the track pitch.

[0013] The eighth method involved in the technology disclosed herein is the magnetic tape involved in any of the methods from the first to the seventh method, wherein the index is controlled to be less than 5% of the track pitch.

[0014] The ninth method of the technology disclosed herein refers to the magnetic tape involved in any of the methods from the first to the eighth method, wherein four or more servo tapes are arranged along the width direction on the magnetic tape as multiple servo tapes, and an index is obtained for each of all pairs of servo tapes that span more than one servo tape in the width direction.

[0015] The tenth method of the technology disclosed herein is the magnetic tape involved in the ninth method, wherein, for each of all pairs of servo tapes spanning more than one servo tape in the width direction, except for a pair of servo tapes not used in data recording and / or playback, an index is obtained.

[0016] The 11th method of the technology disclosed herein is the magnetic tape involved in the 9th or 10th method, wherein the index obtained for each of a pair of servo tapes is controlled to be less than 15% of the track pitch.

[0017] The 12th method of the technology disclosed herein is the magnetic tape involved in the 9th or 10th method, wherein the index obtained for each of a pair of servo tapes is controlled to be less than 10% of the track pitch.

[0018] The 13th method of the technology disclosed herein is the magnetic tape involved in the 9th or 10th method, wherein the index obtained for each of a pair of servo tapes is controlled to be less than 5% of the track pitch.

[0019] The 14th aspect of the technology disclosed herein refers to the magnetic tape involved in any of the 1st to 13th aspects, wherein the servo pattern is at least one pair of linear magnetized regions, the pair of linear magnetized regions being a first linear magnetized region and a second linear magnetized region, the first linear magnetized region and the second linear magnetized region being inclined in opposite directions relative to a virtual straight line along the width direction, and the first linear magnetized region having a steeper inclination angle relative to the virtual straight line compared to the second linear magnetized region.

[0020] The 15th embodiment disclosed herein refers to the magnetic tape involved in any one of the 1st to 14th embodiments, wherein the magnetic tape has a base film composed of polyethylene terephthalate, polyethylene naphthalate, or polyamide.

[0021] The 16th aspect of the technology disclosed herein is a magnetic tape cassette comprising: a magnetic tape as described in any of the 1st to 15th aspects; and a casing for housing the magnetic tape.

[0022] The 17th aspect of the technology disclosed herein is a magnetic tape system comprising: a magnetic tape as described in any of the 1st to 15th aspects; and a magnetic head for recording data on the magnetic tape and / or reproducing data recorded on the magnetic tape.

[0023] The 18th method disclosed herein is an inspection method comprising: obtaining an index from a magnetic tape involved in any of the 1st to 15th methods; and inspecting the magnetic tape using the index.

[0024] The 19th method disclosed herein is the same as the inspection method disclosed in the 18th method, wherein inspecting the magnetic tape includes checking the straightness of the servo pattern using indicators.

[0025] The 20th aspect of the disclosed technology is a method for manufacturing a magnetic tape. The magnetic tape is a tape in which multiple servo tapes, each recording multiple servo patterns along a first length direction, are arranged along their width direction. The method includes: setting a servo write head, having a face (i.e., an opposing face) that faces the recording surface of the tape when recording multiple servo patterns along the first length direction and multiple gap patterns, in an orientation where the recording surface faces the multiple gap patterns. The multiple gap patterns are formed by spacing along a second length direction of the opposing face and correspond to the multiple servo patterns respectively; and using the servo write head in the orientation setting, recording multiple servo patterns along the first length direction on the recording surface, thereby forming multiple servo tapes on the recording surface. The non-linearity index representing the servo patterns is controlled to be less than 15% of the track pitch. The track pitch is determined by the recording element according to the multiple servo patterns... The spacing between multiple tracks formed by recording data of the signal obtained from the pattern on the magnetic tape is an index representing the degree of dispersion of the multiple PES difference gaps from the average value of the multiple PES difference gaps. The PES difference gap is the difference between the first PES difference and the second PES difference. The first PES difference is the difference of PES between a pair of corresponding first positions in the width direction recorded in a pair of servo patterns at corresponding positions in the width direction between a pair of servo tapes that span more than one servo tape in the width direction. The second PES difference is the difference of PES between a pair of second positions in a pair of servo patterns that are offset from a pair of first positions in the width direction by a first predetermined interval. The multiple PES difference gaps are obtained by measuring the PES difference gaps in a pair of servo patterns at every second predetermined interval along the width direction. The first predetermined interval is greater than the second predetermined interval. Attached Figure Description

[0026] Figure 1 This is a conceptual diagram illustrating an example of the structure of a magnetic tape system.

[0027] Figure 2 This is a schematic perspective view showing an example of the appearance of a cassette tape cassette.

[0028] Figure 3 This is a schematic diagram illustrating an example of the hardware structure of a magnetic tape drive.

[0029] Figure 4 This is a schematic perspective view illustrating an example of how a magnetic field is released from the underside of a magnetic tape cassette via a contactless reader / writer.

[0030] Figure 5 This is a conceptual diagram illustrating an example of the relationship between the processing device, the moving mechanism, and the magnetic head.

[0031] Figure 6 This is a conceptual diagram illustrating an example of how the magnetic head is positioned on the magnetic tape when viewed from the surface side.

[0032] Figure 7 This is a conceptual diagram illustrating an example of the structure of a data tape formed on the surface of a magnetic tape.

[0033] Figure 8 This is a conceptual diagram illustrating an example of the correspondence between data recording and playback elements and data tracks.

[0034] Figure 9 This is a conceptual diagram illustrating an example of how a servo pattern is read by a servo reading element.

[0035] Figure 10A This is a conceptual diagram illustrating an example of a data track formed by recording data on the surface of a magnetic tape in an SMR manner on the upper side of the tape in the width direction (between servo tape SB2 and servo tape SB3 within the surface of the tape), where multiple segmented data tracks are staggered and overlapped along the second direction.

[0036] Figure 10B This is a conceptual diagram illustrating an example of a data track formed by recording data on the surface of a magnetic tape in an SMR manner on the lower side in the width direction (between servo tape SB1 and servo tape SB2 within the surface of the magnetic tape), where multiple segmented data tracks are staggered and overlapped along the second direction.

[0037] Figure 11 This is a conceptual diagram illustrating an example of how the first recording module, the regeneration module, and the second recording module are arranged on the magnetic head.

[0038] Figure 12 This is a conceptual diagram illustrating an example of the structure of a servo writer.

[0039] Figure 13 This is a conceptual diagram illustrating an example of the structure of a servo pattern recording head and pulse signal generator included in a servo writer.

[0040] Figure 14This is a flowchart illustrating an example of a linearity inspection method used in the inspection process included in the manufacturing method of magnetic tape.

[0041] Figure 15 This is a conceptual diagram illustrating an example of the structure of a servo tape formed on a magnetic tape.

[0042] Figure 16 This is a conceptual diagram illustrating an example of how multiple ΔdPES are measured based on a servo pattern.

[0043] Figure 17 This is a concept diagram representing an example of a linearity judgment condition.

[0044] Figure 18 This is a diagram illustrating an example of the distribution of multiple dPES obtained from magnetic tape manufactured using conventional techniques without using linearity judgment conditions, and the distribution of multiple dPES obtained from magnetic tape manufactured through a process in which the linearity of the servo pattern is determined to be within the permissible range using linearity judgment conditions.

[0045] Figure 19 This is a chart illustrating an example of the distribution of multiple ΔdPES obtained from a magnetic tape manufactured using conventional techniques without using linearity judgment conditions, and the distribution of multiple ΔdPES obtained from a magnetic tape manufactured through a process in which the linearity of the servo pattern is determined to be within the permissible range using linearity judgment conditions.

[0046] Figure 20A This is a graph showing an example of the distribution of multiple ΔdPES obtained under the first condition shown in Table 1.

[0047] Figure 20B This is a graph showing an example of the distribution of multiple ΔdPES obtained under the second condition shown in Table 2.

[0048] Figure 21 This is a conceptual diagram illustrating an example of how the first recording module reads a servo pattern using the path located at the far end of the tape width among the multiple paths used during data recording.

[0049] Figure 22 This is a conceptual diagram illustrating an example of how a segmented data track is formed by multiple first data recording elements of the first recording module.

[0050] Figure 23 This is a conceptual diagram illustrating an example of a data track formed by multiple first data recording elements of a first recording module, wherein multiple segmented data tracks are staggered and overlapped along a second direction.

[0051] Figure 24This is a conceptual diagram illustrating an example of a regeneration module in which a data regeneration element regenerates data from a segmented data track located at the outermost end of the magnetic tape width among multiple segmented data tracks that form a single data track.

[0052] Figure 25 This is a conceptual diagram illustrating an example of a regeneration module in which a data regeneration element regenerates data from a segmented data track located at the other end of the tape width among multiple segmented data tracks that form a data track.

[0053] Figure 26 This is a conceptual diagram illustrating an example of a data track formed by multiple data recording elements of a recording module, wherein multiple segmented data tracks are staggered and overlapped along a first direction.

[0054] Figure 27 This is a conceptual diagram representing a modified example of the structure of a magnetic head.

[0055] Figure 28 This is a conceptual diagram representing a modified example of the structure of a servo pattern.

[0056] Figure 29 This is a conceptual diagram illustrating an example of the relationship between the geometric characteristics of an actual servo pattern and the geometric characteristics of a virtual servo pattern.

[0057] Figure 30 It means through and Figure 6 The magnetic head shown has more read / write heads and more data recording / reproduction elements compared to the servo read / write head. Figure 6 The diagram shown is a conceptual illustration of an example of magnetic processing using magnetic tapes that have a greater number of data tapes than servo tapes. Detailed Implementation

[0058] Hereinafter, with reference to the accompanying drawings, an example of an embodiment of the magnetic tape, magnetic tape cassette, magnetic tape system, inspection method, and magnetic tape manufacturing method involved in the present disclosure will be described.

[0059] First, the terminology used in the following description will be explained.

[0060] CPU stands for Central Processing Unit. RAM stands for Random Access Memory. NVM stands for Non-Volatile Memory. EEPROM stands for Electrically Erasable and Programmable Read Only Memory. SSD stands for Solid State Drive. HDD stands for Hard Disk Drive. ASIC stands for Application Specific Integrated Circuit. PLD stands for Programmable Logic Device. FPGA stands for Field-Programmable Gate Array. IC stands for Integrated Circuit. RFID stands for Radio Frequency Identifier. UI stands for User Interface. SMR stands for Shingled Magnetic Recording. TDS stands for Transverse Dimensional Stability. FIB stands for Focused Ion Beam. PES stands for Position Error Signal. MEMS stands for Micro Electro Mechanical Systems. PVD stands for Physical Vapor Deposition. CVD stands for Chemical Vapor Deposition.

[0061] As an example, such as Figure 1As shown, the magnetic tape system 10 includes a magnetic tape cassette 12 and a magnetic tape drive 14. The magnetic tape cassette 12 is loaded into the magnetic tape drive 14. The magnetic tape cassette 12 contains a magnetic tape MT. The magnetic tape drive 14 pulls out the magnetic tape MT from the loaded magnetic tape cassette 12, and while driving the pulled-out magnetic tape MT, records data on the magnetic tape MT or reads data from the magnetic tape MT.

[0062] In addition, Figure 1 In the example shown, for ease of understanding of the disclosed technology, the tape cartridge 12 and tape drive 14 are shown separately, but in reality, the tape system 10 has multiple tape cartridges 12 and multiple tape drives 14. Moreover, multiple tape cartridges 12 and multiple tape drives 14 are used selectively.

[0063] For example, according to the given instructions, a tape cartridge 12 is selected from a plurality of tape cartridges 12, and the selected tape cartridge 12 is loaded into a designated tape drive 14 among a plurality of tape drives 14.

[0064] In this embodiment, the magnetic tape system 10 is an example of a "magnetic tape system" as disclosed in this invention. Furthermore, in this embodiment, the magnetic tape MT is an example of a "magnetic tape" as disclosed in this invention. And, in this embodiment, the magnetic tape cassette 12 is an example of a "magnetic tape cassette" as disclosed in this invention.

[0065] Next, refer to Figures 2-4 An example of the structure of the magnetic tape cassette 12 will be described. Furthermore, in the following description, for ease of explanation, [the following will be used...]. Figures 2-4 In the diagram, arrow A indicates the direction in which the tape cassette 12 is loaded into the tape drive 14. Arrow A is defined as the front direction of the tape cassette 12, and the front side of the tape cassette 12 is defined as the front side of the tape cassette 12. In the following description of the structure, "front" refers to the front side of the tape cassette 12.

[0066] Furthermore, in the following description, for ease of explanation, Figures 2-4 In the following description of the structure, arrow B, which is orthogonal to arrow A, is defined as the right direction, and the right side of tape cassette 12 is defined as the right side of tape cassette 12. In the following description of the structure, "right" refers to the right side of tape cassette 12.

[0067] Furthermore, in the following description, for ease of explanation, Figures 2-4 In the following description of the structure, the direction opposite to that of arrow B is defined as the left direction, and the left side of tape cassette 12 is defined as the left side of tape cassette 12. In the following description of the structure, "left" refers to the left side of tape cassette 12.

[0068] Furthermore, in the following description, for ease of explanation, Figures 2-4In the diagram, arrow C represents the direction orthogonal to both arrow A and arrow B. Arrow C is defined as the upward direction of tape cassette 12, and the upward side of tape cassette 12 is defined as the upper side of tape cassette 12. In the following description of the structure, "upper" refers to the upper side of tape cassette 12.

[0069] Furthermore, in the following description, for ease of explanation, Figures 2-4 In this design, the direction opposite to the front direction of the tape cassette 12 is defined as the rear direction of the tape cassette 12, and the rear side of the tape cassette 12 is defined as the rear side of the tape cassette 12. In the following description of the structure, "rear" refers to the rear side of the tape cassette 12.

[0070] Furthermore, in the following description, for ease of explanation, Figures 2-4 In this design, the direction opposite to the upward direction of the tape cassette 12 is defined as the downward direction of the tape cassette 12, and the downward side of the tape cassette 12 is defined as the lower side of the tape cassette 12. In the following description of the structure, "lower" refers to the lower side of the tape cassette 12.

[0071] As an example, such as Figure 2 As shown, the tape cassette 12 is generally rectangular in shape when viewed from above and has a box-shaped outer casing 16. The outer casing 16 houses the magnetic tape MT. The outer casing 16 is an example of the "casing" involved in the technology disclosed herein.

[0072] A feed reel 22 is rotatably housed inside the housing 16. The magnetic tape MT is wound onto the feed reel 22. An opening 16A1 is formed on the front side of the right wall 16A of the housing 16. The magnetic tape MT is pulled out from the opening 16A1.

[0073] The housing 16 houses a cartridge memory 24 as a storage medium other than the magnetic tape MT. The cartridge memory 24 contains an IC chip with NVM. In this embodiment, a so-called passive RFID tag is used as the cartridge memory 24, and various information is read and written (i.e., stored and retrieved) in a non-contact manner.

[0074] The cartridge memory 24 stores management information 15 for managing the tape cartridge 12. For example, the management information 15 includes information related to the cartridge memory 24, information related to the tape MT, information related to the tape system 10, and information related to the tape drive 14.

[0075] The magnetic tape (MT) has a base film as a non-magnetic support and a magnetic layer containing a strongly magnetic powder. The base film (hereinafter also simply referred to as the "support") can be, for example, biaxially stretched polyethylene terephthalate, polyethylene naphthalate, polyamide, polyamide-imide, or aromatic polyamide, among other known base films. The strongly magnetic powder can be, for example, a strongly magnetic powder commonly used in the magnetic layers of various magnetic recording media. A preferred example of a strongly magnetic powder is hexagonal ferrite powder. Examples of hexagonal ferrite powders include hexagonal strontium ferrite powder or hexagonal barium ferrite powder.

[0076] In one embodiment, the base film of the magnetic tape MT can be an aromatic polyester support. In this disclosure and specification, "aromatic polyester" refers to a resin containing an aromatic backbone and multiple ester bonds, and "aromatic polyester support" refers to a support containing at least one layer of aromatic polyester film. "Aromatic polyester film" refers to a film in which aromatic polyester constitutes the largest component by mass. In this disclosure and specification, "aromatic polyester support" includes supports in which all resin films are aromatic polyester films, and supports containing aromatic polyester films and other resin films. Specific examples of aromatic polyester supports include single-layer aromatic polyester films, laminated films with two or more layers of aromatic polyester films of the same composition, laminated films with two or more layers of aromatic polyester films of different compositions, and laminated films containing one or more layers of aromatic polyester films and one or more layers of resin films other than aromatic polyester films. An adhesive layer may also be arbitrarily included between adjacent layers in a laminated film. Furthermore, the aromatic polyester support may also optionally contain a metal film and / or a metal oxide film formed on one or both surfaces by vapor deposition or the like. The same applies to the "polyethylene terephthalate support" and "polyethylene naphthalate support" in this disclosure and specification.

[0077] The aromatic rings contained in the aromatic backbone of aromatic polyesters are not particularly limited. Specific examples of aromatic rings include benzene rings or naphthalene rings. For example, polyethylene terephthalate (PET) is a polyester containing benzene rings and is a resin obtained by polycondensation of ethylene glycol with terephthalic acid and / or dimethyl terephthalate. The term "polyethylene terephthalate" in this disclosure and specification also includes compounds having a structure containing one or more other components (e.g., copolymer components, components introduced into the ends or side chains, etc.) in addition to the components described above. Polyethylene naphthalate (PEN) is a polyester containing naphthalene rings and is a resin obtained by esterification of dimethyl 2,6-naphthalate with ethylene glycol followed by transesterification and polycondensation. The term "polyethylene naphthalate" in this invention and specification also includes compounds having a structure containing one or more other components (e.g., copolymer components, components introduced into the ends or side chains, etc.) in addition to the components described above.

[0078] Furthermore, in one embodiment, the base film of the magnetic tape MT can be an aromatic polyamide support. In this disclosure and specification, "aromatic polyamide" refers to a resin containing an aromatic backbone and multiple amide bonds. The aromatic rings contained in the aromatic backbone of the aromatic polyamide are not particularly limited. Specific examples of aromatic rings include, for example, benzene rings. "Aromatic polyamide support" refers to a support containing at least one layer of aromatic polyamide film. "Aromatic polyamide film" refers to a film in which aromatic polyamide constitutes the largest component by mass. In this disclosure and specification, "aromatic polyamide support" includes supports in which all resin films are aromatic polyamide films and supports containing aromatic polyamide films and other resin films. Specific examples of aromatic polyamide supports include single-layer aromatic polyamide films, laminated films consisting of two or more aromatic polyamide films with the same composition, laminated films consisting of two or more aromatic polyamide films with different compositions, and laminated films containing one or more aromatic polyamide films and one or more resin films other than aromatic polyamide films. An adhesive layer may also be arbitrarily included between adjacent layers in the laminated film. Furthermore, the aromatic polyamide support may arbitrarily include a metal film and / or a metal oxide film formed on one or both surfaces by means of vapor deposition, etc.

[0079] Furthermore, the base film can be a biaxially stretched film, or a film that has undergone corona discharge, plasma treatment, easy bonding treatment, or heat treatment.

[0080] As an indicator of the physical properties of the base film, moisture content can be listed as an example. In this invention and this specification, the moisture content of the base film is a value obtained by the following method. The moisture content shown in the table below is a value obtained by the following method. A sample piece (e.g., a sample piece of several grams) cut from the base film to which the moisture content is to be measured is dried to constant weight in a vacuum desiccator at a temperature of 180°C and a pressure of 100 Pa (Pascal). The mass of the sample piece thus dried is defined as W1. W1 is the value measured within 30 seconds after being removed from the vacuum desiccator at a temperature of 23°C and a relative humidity of 50%. Then, the mass of the sample piece after being placed in an environment at a temperature of 25°C and a relative humidity of 75% for 48 hours is defined as W2. W2 is the value measured within 30 seconds after being removed from the above environment at a temperature of 23°C and a relative humidity of 50%. The moisture content is calculated by the following formula.

[0081] Moisture content (%) = [(W2-W1) / W1] × 100 For example, after removing the magnetic layer and other parts other than the base film from the magnetic tape MT by known methods (e.g., stripping using organic solvents), the moisture content of the base film can be determined by the above method.

[0082] In one embodiment, the moisture content of the base film of the magnetic tape MT is preferably 2.0% or less, more preferably 1.8% or less, even more preferably 1.6% or less, even more preferably 1.4% or less, even more preferably 1.2% or less, and even more preferably 1.0% or less. Furthermore, the moisture content of the base film of the magnetic tape MT can be 0%, 0% or more, more than 0%, or 0.1% or more. Using a base film with low moisture content helps to increase the media life of each magnetic tape cartridge 12. This is mainly because using a base film with low moisture content helps to reduce the value of "B" obtained by the method described above.

[0083] Young's modulus can also be listed as an indicator of the physical properties of the base film. In this invention and this specification, the Young's modulus of the base film is the value measured under the following method at a temperature of 23°C and a relative humidity of 50%. The Young's modulus shown in the table below is the value obtained using a Tensilon manufactured by TOYO BALDWIN CO.Ltd. as a universal tensile testing apparatus and by the following method.

[0084] A sample piece cut from the base film of the test object is subjected to tensile testing using a universal tensile testing apparatus under conditions of a clamp spacing of 100 mm, a tensile speed of 10 mm / min, and a recording paper speed of 500 mm / min. As a universal tensile testing apparatus, commercially available universal tensile testing apparatuses such as the Tensilon apparatus manufactured by TOYO BALDWIN CO.Ltd., or universal tensile testing apparatuses with known structures, can be used. Based on the tangent at the beginning of the load-elongation curve thus obtained, the Young's modulus of the sample piece in both the length and width directions is calculated. Here, the length and width directions of the sample piece refer to the length and width directions when the sample piece is contained within the magnetic tape MT.

[0085] For example, after removing the magnetic layer and other parts other than the base film from the magnetic tape MT by known methods (e.g., stripping using organic solvents), the Young's modulus of the base film in the length and width directions can be determined by the above method.

[0086] In one embodiment, the Young's modulus of the base film of the magnetic tape MT in the longitudinal direction is preferably 3000 MPa or more, more preferably 4000 MPa or more, further preferably 5000 MPa or more, and even more preferably 6000 MPa or more. Furthermore, the Young's modulus of the base film in the longitudinal direction of the magnetic tape MT can be 15000 MPa or less, 13000 MPa or less, or 12000 MPa or less. Regarding the width direction, the Young's modulus of the base film in the width direction of the magnetic tape MT is preferably 2000 MPa or more, more preferably 3000 MPa or more, further preferably 4000 MPa or more, and even more preferably 5000 MPa or more. Furthermore, the Young's modulus of the base film in the width direction of the magnetic tape MT can be 12000 MPa or less, 11000 MPa or less, or 10000 MPa or less. When manufacturing the magnetic tape MT, the base film is typically used with the machine direction (MD) of the film as the length direction and the transverse direction (TD) as the width direction. Furthermore, in one embodiment, it is preferable that the Young's modulus in the length direction is greater than that in the width direction, and more preferably the difference (Young's modulus in the length direction - Young's modulus in the width direction) is in the range of 800 to 3000 MPa. The dielectric lifetime of each magnetic tape cartridge 12 can also be controlled by the Young's modulus of the base film.

[0087] The moisture content and Young's modulus of the base film can be controlled by the types and mixing ratios of the components constituting the support, as well as the manufacturing conditions of the support. For example, by adjusting the stretching ratio in each direction during biaxial stretching, the Young's modulus in the length direction and the Young's modulus in the width direction can be controlled separately.

[0088] As an example, such as Figure 3 As shown, the tape drive 14 includes a controller 25, a transfer device 26, a magnetic head 28, and a user interface (UI) system device 29. The controller 25 includes a processing device 30 and a storage device 32. In this embodiment, the magnetic head 28 is an example of a "magnetic head" as disclosed in this invention.

[0089] The tape cassette 12 is loaded into the tape drive 14 in the direction of arrow A. The tape MT is pulled out of the tape cassette 12 and used in the tape drive 14. The tape drive 14 uses management information 15 and other information stored in the cartridge memory 24 to control the tape cassette 12 and the various parts within the tape drive 14.

[0090] The magnetic tape drive 14 uses the magnetic head 28 to perform magnetic processing on the surface 31 of the magnetic tape MT while the magnetic tape MT is being fed. Surface 31 is the recording surface for recording data. Magnetic processing refers to the recording process in which the magnetic head 28 records data on the magnetic surface 31 of the magnetic tape MT, and the playback process in which the magnetic head 28 reads data from the surface 31 of the magnetic tape MT. In this embodiment, the magnetic tape drive 14 selectively performs recording and playback processes using the magnetic head 28. That is, the magnetic tape drive 14 pulls the magnetic tape MT out of the tape cartridge 12 and records data on the surface 31 of the pulled-out magnetic tape MT using the magnetic head 28, or reads data from the surface 31 of the pulled-out magnetic tape MT using the magnetic head 28. In this embodiment, surface 31 is an example of the "recording surface" involved in the technology disclosed herein.

[0091] The processing device 30 controls the entire tape drive 14. In this embodiment, the processing device 30 is implemented using an ASIC, but the technology disclosed herein is not limited to this. For example, the processing device 30 can also be implemented using an FPGA and / or a PLD. Furthermore, the processing device 30 can also be implemented using a computer that includes a CPU, flash memory (e.g., EEPROM and / or SSD), and RAM. It can also be implemented by combining two or more of the following: ASIC, FPGA, PLD, and computer. That is, the processing device 30 can be implemented using a combination of hardware and software architectures.

[0092] Storage device 32 is connected to processing device 30, which writes and reads various information from storage device 32. Examples of storage device 32 include flash memory and / or HDD. Flash memory and HDD are just examples; any non-volatile memory that can be mounted on tape drive 14 can be used.

[0093] UI system device 29 is a device having a receiving function for receiving instruction signals indicating instructions from a user and a prompting function for providing prompting information to the user. The receiving function is implemented, for example, via a touch panel, hard keys (e.g., a keyboard), and / or a mouse. The prompting function is implemented, for example, via a display, a printer, and / or a speaker. UI system device 29 is connected to processing device 30. Processing device 30 acquires the instruction signals received through UI system device 29. Under the control of processing device 30, UI system device 29 prompts various information to the user.

[0094] The conveying device 26 is a device that selectively conveys the magnetic tape MT in both forward and reverse directions along a predetermined path, and includes a feed motor 36, a reel 38, a winding motor 40, and multiple guide rollers GR. Here, "forward" refers to the feeding direction of the magnetic tape MT, and "reverse" refers to the rewind direction of the magnetic tape MT.

[0095] Under the control of the processing device 30, the tape supply motor 36 causes the tape supply reel 22 inside the tape cassette 12 to rotate. The processing device 30 controls the rotation direction, rotation speed, and rotation torque of the tape supply reel 22 by controlling the tape supply motor 36.

[0096] The tape reel 38 is rotated by the tape motor 40 under the control of the processing device 30. The processing device 30 controls the rotation direction, rotation speed, and rotation torque of the tape reel 38 by controlling the tape motor 40.

[0097] When the magnetic tape MT is wound onto the reel 38, the processing device 30 rotates the feed motor 36 and the winding motor 40 to feed the magnetic tape MT forward along a predetermined path. The rotational speed and torque of the feed motor 36 and the winding motor 40 are adjusted according to the speed at which the magnetic tape MT is wound onto the reel 38. Furthermore, by adjusting the rotational speed and torque of the feed motor 36 and the winding motor 40 respectively using the processing device 30, tension is applied to the magnetic tape MT. The tension applied to the magnetic tape MT is controlled by adjusting the rotational speed and torque of the feed motor 36 and the winding motor 40 respectively using the processing device 30.

[0098] When the magnetic tape MT is rewound to the feed reel 22, the processing device 30 causes the feed motor 36 and the winding motor 40 to rotate so that the magnetic tape MT travels in the reverse direction along a predetermined path.

[0099] Multiple guide rollers GR are rollers that guide the magnetic tape MT. The predetermined path, i.e. the tape travel path of the magnetic tape MT, is determined by separately arranging multiple guide rollers GR at the position across the magnetic head 28 between the tape cartridge 12 and the reel 38.

[0100] The magnetic head 28 includes a magnetic element unit 42 and a support 44. The magnetic element unit 42 is held by the support 44 to contact the magnetic tape MT in the tape transport. The magnetic element unit 42 has multiple magnetic elements.

[0101] The magnetic element unit 42 records data on the magnetic tape MT transmitted by the transmission device 26, or replays data from the magnetic tape MT transmitted by the transmission device 26. Here, data refers, for example, to the servo pattern 52 (see reference). Figure 6 ) and data other than servo pattern 52 (i.e., recorded on the data tape DB (see reference) Figure 6 (Data).

[0102] The tape drive 14 includes a contactless read / write device 46. The contactless read / write device 46 is configured such that the underside of the tape cassette 12, which is loaded with tape cassette 12, faces the back of the cartridge memory 24, and reads and writes information to the cartridge memory 24 in a contactless manner.

[0103] As an example, such as Figure 4 As shown, the non-contact read / write device 46 releases a magnetic field MF from the underside of the tape cartridge 12 toward the cartridge memory 24. The magnetic field MF penetrates the cartridge memory 24.

[0104] The contactless reader / writer 46 is connected to the processing unit 30. The processing unit 30 outputs a control signal to the contactless reader / writer 46. The control signal is a signal that controls the cartridge memory 24. The contactless reader / writer 46 generates a magnetic field MF according to the control signal input from the processing unit 30, and releases the generated magnetic field MF toward the cartridge memory 24.

[0105] The contactless reader / writer 46 communicates with the cartridge memory 24 via a magnetic field MF, thereby performing processing on the cartridge memory 24 in accordance with control signals. For example, under the control of the processing unit 30, the contactless reader / writer 46 selectively performs processing to read information from the cartridge memory 24 and processing to store information in the cartridge memory 24 (i.e., processing to write information to the cartridge memory 24). In other words, the processing unit 30 communicates with the cartridge memory 24 in a contactless manner via the contactless reader / writer 46, thereby reading information from the cartridge memory 24 or storing information in the cartridge memory 24.

[0106] As an example, such as Figure 5 As shown, the processing device 30 is connected to the magnetic head 28, and uses the magnetic field MF generated by the magnetic head 28 (reference) Figure 4 The processing device 30 controls the processing of the magnetic head 28 (e.g., the magnetic processing described above). The magnetic tape drive 14 includes a moving mechanism 48. The processing device 30 is connected to the magnetic head 28 via the moving mechanism 48. The processing device 30 controls the movement of the magnetic head 28 via the moving mechanism 48 (e.g., the magnetic tape MT moves in the width direction WD (refer to...). Figure 6 The movement on the device is controlled.

[0107] The moving mechanism 48 has a moving actuator 48A. Examples of moving actuators 48A include voice coil motors and / or piezoelectric actuators. The moving actuator 48A is connected to the processing unit 30, and the processing unit 30 controls the moving actuator 48A. The moving actuator 48A generates power under the control of the processing unit 30. The moving mechanism 48 receives the power generated by the moving actuator 48A, thereby moving the magnetic head 28 along the width direction WD of the magnetic tape MT (see reference). Figure 6 ).

[0108] As an example, such as Figure 6 As shown, servo tapes SB1, SB2, and SB3 and data tapes DB1 and DB2 are formed on the surface 31 of the magnetic tape MT. In this embodiment, servo tapes SB1, SB2, and SB3 are an example of the "multiple servo tapes" disclosed herein. Furthermore, for ease of explanation, servo tapes SB1 to SB3 will be referred to as "servo tapes SB" and data tapes DB1 and DB2 as "data tapes DB" unless otherwise specified.

[0109] Servo tapes SB1 to SB3 and data tapes DB1 and DB2 are formed along the length direction LD (i.e., the entire length direction) of the magnetic tape MT. In other words, the length direction LD refers to the tape travel direction of the magnetic tape MT. The tape travel direction of the magnetic tape MT is defined as the direction in which the tape MT travels from the feed reel 22 side to the reel 38 side, i.e., the forward direction (hereinafter also simply referred to as "forward"), and the direction in which the tape MT travels from the reel 38 side to the feed reel 22 side, i.e., the reverse direction (hereinafter also simply referred to as "reverse"). In this embodiment, the length direction LD is an example of the "length direction" and "first length direction" involved in the technology disclosed herein.

[0110] Servo tapes SB1 to SB3 are arranged at separate positions along the width direction WD (hereinafter also referred to as "width direction WD") of the magnetic tape MT. For example, servo tapes SB1 to SB3 are arranged at equal intervals along the width direction WD.

[0111] Furthermore, in this embodiment, "equal spacing" means, in the sense that, apart from completely equal spacing, it includes errors that are generally permissible in the technical field to which this disclosure pertains and do not depart from the spirit of this disclosure. Moreover, in this embodiment, the width direction WD is an example of the "width direction" involved in this disclosure.

[0112] Data band DB1 is positioned between servo bands SB1 and SB2, and data band DB2 is positioned between servo bands SB2 and SB3. That is, servo bands SB and data bands DB are arranged alternately along the width direction WD.

[0113] In addition, Figure 6 In the example shown, for ease of explanation (to facilitate understanding of the technology disclosed herein), 3 servo bands SB and 2 data bands DB are shown. However, this is only one example, and it can also be 2 servo bands SB and 1 data band DB. Even if there are more than 4 servo bands SB and more than 3 data bands DB, the technology disclosed herein still applies.

[0114] Multiple servo patterns 52 are recorded along the length direction LD on the servo tape SB. The servo patterns 52 are divided into servo pattern 52A and servo pattern 52B. The multiple servo patterns 52 are arranged at predetermined intervals along the length direction LD. Furthermore, in this embodiment, "prescribed" means, in the sense of including errors that are generally permissible in the technical field to which this disclosure pertains, without departing from the spirit of the technical disclosure, other than a complete specification.

[0115] The servo band SB is divided along the length direction LD by multiple frames 50. Frames 50 are defined by a set of servo patterns 52. Figure 6 In the example shown, servo patterns 52A and 52B are shown as one example of a set of servo patterns 52. Servo patterns 52A and 52B are adjacent along the length direction LD. Within frame 50, servo pattern 52A is located on the upstream side in the positive direction, and servo pattern 52B is located on the downstream side in the positive direction.

[0116] The servo pattern 52 is composed of linear magnetized region pairs 54. The linear magnetized region pairs 54 are divided into linear magnetized region pairs 54A and linear magnetized region pairs 54B.

[0117] Servo pattern 52A is composed of linear magnetized regions paired with 54A. In Figure 6 In the example shown, as an example of a linear magnetization region pair 54A, a pair of regions consisting of linear magnetization regions 54A1 and 54A2 are shown. Linear magnetization regions 54A1 and 54A2 are regions that are linearly magnetized.

[0118] The linear magnetization regions 54A1 and 54A2 are tilted in the opposite direction to the virtual straight line C1 along the width direction WD. Figure 6 In the example shown, the linear magnetization regions 54A1 and 54A2 are tilted symmetrically with respect to the virtual straight line C1. More specifically, the linear magnetization regions 54A1 and 54A2 are not parallel to each other and are tilted at a predetermined angle (e.g., 5 degrees) in the opposite direction to the LD side of the symmetrical axial length direction of the virtual straight line C1.

[0119] Linear magnetization region 54A1 is a set of 5 magnetized straight lines, namely magnetization line 54A1a. Linear magnetization region 54A2 is a set of 5 magnetized straight lines, namely magnetization line 54A2a.

[0120] Servo pattern 52B is composed of linear magnetized regions paired with 54B. In Figure 6 In the example shown, as an example of a linear magnetization region pair 54B, a pair of regions consisting of linear magnetization regions 54B1 and 54B2 is shown. Linear magnetization regions 54B1 and 54B2 are regions that are linearly magnetized.

[0121] The linear magnetization regions 54B1 and 54B2 are tilted in the opposite direction to the virtual straight line C2 along the width direction WD. Figure 6 In the example shown, the linear magnetization regions 54B1 and 54B2 are tilted symmetrically with respect to the virtual straight line C2. More specifically, the linear magnetization regions 54B1 and 54B2 are not parallel to each other and are tilted at a predetermined angle (e.g., 5 degrees) in the opposite direction of the LD side of the symmetrical axial length direction of the virtual straight line C2.

[0122] Linear magnetization region 54B1 is a set of four magnetized straight lines, namely magnetization line 54B1a. Linear magnetization region 54B2 is a set of four magnetized straight lines, namely magnetization line 54B2a.

[0123] A magnetic head 28 is disposed on the surface 31 side of the magnetic tape MT thus configured. A support 44 is formed in a cuboid shape and is arranged to span the surface 31 of the magnetic tape MT along its width direction WD. Multiple magnetic elements of the magnetic element unit 42 are arranged in a straight line along the length direction of the support 44. Figure 6 In the example shown, the length direction of the magnetic head 28, i.e. the length direction of the bracket 44, is consistent with the width direction WD.

[0124] The magnetic element unit 42 has three servo read elements SR and multiple data recording and playback elements DRW as multiple magnetic elements. Here, for ease of understanding of this disclosure, three servo read elements SR are illustrated, but this is only an example, and this disclosure still applies even if there are four or more servo read elements SR.

[0125] The length of the support 44 in the longitudinal direction is sufficiently long relative to the width of the magnetic tape MT. For example, the length of the support 44 in the longitudinal direction is set such that it exceeds the width of the magnetic tape MT even if the magnetic element unit 42 is arranged in any position on the magnetic tape MT.

[0126] Three servo read elements SR are mounted on the read / write head 28. The relative positional relationship between the support 44 and the three servo read elements SR on the read / write head 28 is fixed. The three servo read elements SR are composed of servo read elements SR1, SR2, and SR3. The servo read elements SR1, SR2, and SR3 are arranged at intervals along the length of the support 44 (for example, arranged at equal intervals along the length of the support 44).

[0127] Servo read element SR1 is disposed at one end of magnetic element unit 42. Servo read element SR3 is disposed at the other end of magnetic element unit 42. Servo read element SR2 is disposed between servo read elements SR1 and SR3 along the length of the magnetic head 28 (here, as an example, the center). Figure 6 In the example shown, the servo readout element SR1 is positioned corresponding to the servo band SB3. Furthermore, in Figure 6 In the example shown, the servo readout element SR2 is positioned corresponding to the servo band SB2. Furthermore, in Figure 6 In the example shown, the servo readout element SR3 is positioned corresponding to the servo band SB1.

[0128] Multiple data recording and playback elements (DRWs) are arranged in a straight line between servo read elements SR1 and SR2, and between servo read elements SR2 and SR3, respectively. These DRWs are also spaced apart along the length of the magnetic head 28 (e.g., equally spaced along the length of the magnetic head 28). Figure 6 In the example shown, multiple data record regeneration elements (DRWs) are positioned at the locations corresponding to data tape DB2 and data tape DB1, respectively.

[0129] The processing device 30 acquires the result obtained by the servo pattern 52 read by the servo reading element SR, namely the servo pattern signal, and performs servo control according to the acquired servo pattern signal. In this embodiment, the servo pattern signal is an example of the "signal" involved in the technology disclosed herein.

[0130] Here, servo control refers to the control that moves the magnetic head 28 along the width direction WD of the magnetic tape MT by causing the moving mechanism 48 to move according to the servo pattern 52 read by the servo reading element SR.

[0131] Through servo control, multiple data recording and playback elements (DRWs) are positioned in a designated area within the data band DB, and in this state, magnetic processing is performed on the designated area within the data band DB. Figure 6In the example shown, multiple data recording and reproducing elements (DRWs) perform magnetic processing on a specified area within the data band DB2.

[0132] As an example, such as Figure 7 As shown, in data band DB2, data tracks DT1, DT2, DT3, DT4, DT5, DT6, DT7 and DT8 are formed from the servo band SB2 side to the servo band SB3 side as multiple segmented regions obtained by dividing data band DB2 along the width direction WD.

[0133] The magnetic head 28 has multiple data recording and playback elements DRW1, DRW2, DRW3, DRW4, DRW5, DRW6, DRW7, and DRW8 along the width direction WD between the servo read element SR1 and the servo read element SR2. The data recording and playback elements DRW1 to DRW8 correspond one-to-one with the data tracks DT1 to DT8, and can reproduce data from the data tracks DT1 to DT8 (i.e., read) and record data on the data tracks DT1 to DT8 (i.e., write).

[0134] Hereinafter, without special distinction, data tracks DT1, DT2, DT3, DT4, DT5, DT6, DT7, and DT8 will be referred to as "data track DT". Furthermore, without special distinction, data recording and playback elements DRW1, DRW2, DRW3, DRW4, DRW5, DRW6, DRW7, and DRW8 will be referred to as "data recording and playback elements DRW".

[0135] Additionally, although the illustration is omitted, it is in data band DB1 (reference). Figure 6 On the ), multiple data tracks DT are also formed, which are equivalent to data tracks DT1, DT2, DT3, DT4, DT5, DT6, DT7 and DT8.

[0136] As an example, such as Figure 8 As shown, data track DT has a segmented data track group DTG. Data tracks DT1 to DT8 correspond to segmented data track groups DTG1 to DTG8. Hereinafter, unless otherwise specified, segmented data track groups DTG1 to DTG8 will be referred to as "segmented data track group DTG".

[0137] The segmented data track group DTG1 is a collection of multiple segmented data tracks obtained by dividing the data track DT along the width direction WD. Figure 8In the example shown, as a case of a segmented data track group DTG1, segmented data tracks DT_1, DT_2, DT_3, DT_4, ..., DT_11 and DT_12 are shown, obtained by dividing the data track DT into 12 equal parts along the width direction WD. The data recording and playback element DRW1 is responsible for magnetic processing of the segmented data track group DTG1. That is, the data recording and playback element DRW1 is responsible for recording data from the segmented data tracks DT_1, DT_2, DT_3, DT_4, ..., DT_11 and DT_12, and for reproducing data from the segmented data tracks DT_1, DT_2, DT_3, DT_4, ..., DT_11 and DT_12. Hereinafter, without distinction, the segmented data tracks DT_1, DT_2, DT_3, DT_4, ..., DT_11 and DT_12 will be referred to as "segmented data track DT_N".

[0138] The data recording and playback elements DRW2 to DRW8, like the data recording and playback element DRW1, are responsible for performing magnetic processing on the segmented data track group DTG corresponding to the data track DT of each data recording and playback element DRW.

[0139] The data recording and regeneration element DRW is moved by the moving mechanism 48 (reference). Figure 6 The read / write head 28 is moved in the width direction WD (i.e., along the length direction of the read / write head 28) to a position corresponding to a specified data track DT among multiple data tracks DT. This is achieved by using servo pattern 52 (reference). Figure 6 and Figure 7 Servo control is performed, and the data recording and regeneration element DRW stops at the position corresponding to the specified data track DT.

[0140] As an example, such as Figure 9 As shown, paths P1 to P12 are evenly spaced along the width direction WD in servo pattern 52. Paths P1 to P12 are connected to multiple segmented data tracks DT_N contained in the segmented data track group DTG (in... Figure 8 and Figure 9 The example shown corresponds to 12 split data tracks (DT_N). Paths P1 to P12 are roughly divided into paths Pa1 to Pa12 used when recording data and paths Pb1 to Pb12 used when reproducing data. Hereinafter, when there is no need to distinguish between paths P1 to P12, they will be referred to as "path P".

[0141] When the data recording and playback element DRW performs magnetic processing on the segmented data track DT_N designated as the target of magnetic processing, the moving mechanism 48 moves the read / write head 28 along the width direction WD so that the servo read / write element SR passes through the path P corresponding to the target segmented data track. For example, when the data recording and playback element DRW performs magnetic processing on the segmented data track DT_1, the moving mechanism 48 moves the read / write head 28 along the width direction WD so that the servo read / write element SR passes through path P1. Similarly, for example, when the data recording and playback element DRW performs magnetic processing on the segmented data track DT_12, the moving mechanism 48 moves the read / write head 28 along the width direction WD so that the servo read / write element SR passes through path P12. Thus, the data recording and playback element DRW1 faces the target segmented data track, enabling magnetic processing of the target segmented data track.

[0142] Here, for reference Figure 10A and Figure 10B This paper will explain an example of a magnetic tape (MT) method in which data is recorded using the SMR method. Figure 10A This is a conceptual diagram illustrating an example of a method in which data is recorded on the surface 31 of magnetic tape MT in an SMR manner on the data tape DB2 between servo tape SB2 and servo tape SB3, and multiple segmented data tracks DT_N are offset and overlapped along the other end of the width of magnetic tape MT to form a data track DT. Figure 10B This is a conceptual diagram illustrating an example of a method in which multiple segmented data tracks DT_N are staggered and overlapped along the other side of the width of the magnetic tape MT to form a data track DT, which is achieved by recording data on the surface 31 of the magnetic tape MT in an SMR manner on the data tape DB1 between the servo tape SB1 and the servo tape SB2.

[0143] As an example, such as Figure 10A and Figure 10B As shown, all the subdivided data tracks DT_N that form a data track DT (here, as an example, 12 subdivided data tracks DT_N) are formed by recording data onto the magnetic tape MT in SMR mode by the data recording and playback element DRW. SMR mode is a magnetic recording method used to achieve high-density data recording on the magnetic tape MT, also known as shingled recording mode.

[0144] exist Figure 10A and Figure 10BIn the example shown, the width direction WD is defined by the direction at one end of the width of the magnetic tape MT, i.e., the first direction WD1, and the direction at the other end of the width of the magnetic tape MT, i.e., the second direction WD2. The second direction WD2 is the direction in which data is staggered on the magnetic tape MT by recording data in SMR mode. Multiple segmented data tracks DT_N of each data track DT are recorded on the magnetic tape MT in a staggered and overlapping manner along the second direction WD2. For a data track DT, adjacent segmented data tracks DT_N in the width direction WD are staggered by a specified spacing Tp along the width direction WD.

[0145] In this embodiment, the multiple segmented data tracks DT_N of each data track DT is an example of the "multiple tracks" involved in the disclosed technology. Furthermore, in this embodiment, the spacing Tp is an example of the "track spacing" involved in the disclosed technology. Additionally, in... Figure 10A and Figure 10B In the example shown, to make it easier to understand the configuration relationship of the split data tracks DT_1 to DT_12, the split data tracks DT_1 to DT_12 are deliberately staggered along the length direction LD. However, in reality, the split data tracks DT_1 to DT_12 are not staggered along the length direction LD, but rather the split data tracks DT_1 to DT_12 extend along the length direction LD.

[0146] Guard bands (GB) are formed between data tracks (DT) in the width direction (WD). The guard bands (GB) are blank areas not used for data recording and playback. For example, the guard bands (GB) formed between data tracks (DT) serve the following function: to prevent the influence of magnetic processing on one data track (DT) from affecting the other data track (DT) due to variations in the spacing between data recording and playback elements (DRW) (e.g., variations within manufacturing tolerances).

[0147] Furthermore, a guard band GB is formed between the servo band SB and the data band DB in the width direction WD. For example, the guard band GB between the servo band SB and the data band DB serves the following function: to prevent the magnetic influence caused by the servo read element SR on the servo band SB from affecting the data track DT, or the magnetic influence caused by the data recording and playback element DRW from affecting the servo band SB.

[0148] As an example, such as Figure 11 As shown, the magnetic head 28 includes a first recording module DWM1, a second recording module DWM2, and a regeneration module DRM. Hereinafter, for ease of explanation, the first recording module DWM1 and the second recording module DWM2 will be referred to as "recording module DWM" without distinction.

[0149] The recording module DWM and the regeneration module DRM are along the length direction LD (in other words, in...) Figure 11 The example shown is configured along the short side of the magnetic head 28. For example, along the length direction LD, a recording module DWM is configured on each side of the regeneration module DRM. Figure 11 The example shown schematically illustrates the relationship between and Figure 3 Observe in the opposite direction to the direction indicated by arrow B. Figure 3 The example shown is of the surface side of the magnetic head 28, with the feed reels 22 on both sides of the regeneration module DRM along the length direction LD (see reference). Figure 3 The first recording module DWM1 is configured on the side, and the tape reels 38 (see reference) are located on both sides of the regeneration module DRM in the length direction LD. Figure 3 The second recording module DWM2 is configured on the side.

[0150] Magnetic element units 42 are provided on the recording module DWM and the playback module DRM. Magnetic element unit 42 includes servo read elements SR1, SR2, and SR3, a first data recording element group DWG1, a second data recording element group DWG2, and a data playback element group DRG. The first data recording element group DWG1 is located on the first recording module DWM1. The second data recording element group DWG2 is located on the second recording module DWM2. The data playback element group DRG is located on the playback module DRM.

[0151] Servo read element SR1 is located at one end of magnetic element unit 42, and servo read element SR3 is located at the other end of magnetic element unit 42. Furthermore, servo read element SR2 is located at the center of servo read element SR1 and servo read element SR3 among all the magnetic elements constituting magnetic element unit 42.

[0152] A data recording and playback element DRW is provided between servo reading element SR1 and servo reading element SR2, and between servo reading element SR2 and servo reading element SR3, respectively. The servo recording and playback element DRW has a first data recording element DW1, a second data recording element DW2, and a data playback element DR.

[0153] The first data recording element group DWG1 contains a plurality of first data recording elements DW1, and the plurality of first data recording elements DW1 are along the width direction WD (in other words, in Figure 11 In the example shown, the magnetic head 28 is arranged in a straight line along its length. The arrangement of the plurality of first data recording elements DW1 is parallel to the surface 31 of the magnetic tape MT and parallel to the width direction WD (in other words, orthogonal to the length direction LD).

[0154] The second data recording element group DWG2 includes a plurality of second data recording elements DW2, and the plurality of second data recording elements DW2 are arranged in a straight line along the width direction WD. The arrangement direction of the plurality of second data recording elements DW2 is parallel to the surface 31 of the magnetic tape MT and parallel to the width direction WD (in other words, orthogonal to the length direction LD).

[0155] The data regeneration element group DRG contains multiple data regeneration elements DR, and the multiple data regeneration elements DR are arranged in a straight line along the width direction WD. The arrangement direction of the multiple data regeneration elements DR is parallel to the surface 31 of the magnetic tape MT and parallel to the width direction WD (in other words, orthogonal to the length direction LD).

[0156] For ease of explanation, without distinguishing between the first data recording element DW1 and the second data recording element DW2, the first data recording element DW1 and the second data recording element DW2 will be referred to as "data recording element DW". In this embodiment, the data recording element DW is an example of the "recording element" involved in the technology disclosed herein.

[0157] The data recording element (DW) records data onto the data track (DT). The data playback element (DR) replays data from the data track (DT).

[0158] The first data recording element group DWG1, the second data recording element group DWG2, and the data playback element group DRG are arranged along the length direction LD, from the feed reel 22 side to the reel 38 side, with a predetermined interval between them in the order of the first data recording element group DWG1, the data playback element group DRG, and the second data recording element group DWG2. Here, the predetermined interval refers, for example, to an interval that will not cause crosstalk between the data recording element DW and the data playback element DR, and is predetermined through experiments and / or computer simulations using actual equipment.

[0159] The servo read element SR has a first servo read element SRa, a second servo read element SRb, and a third servo read element SRc. That is, servo read elements SR1, SR2, and SR3 each have a first servo read element SRa, a second servo read element SRb, and a third servo read element SRc.

[0160] The first servo read element SRa, the second servo read element SRb, and the third servo read element SRc feed reel 22 from the length direction LD (reference). Figure 3 Side to reel 38 (reference) Figure 3 On the side, the first servo read element SRa, the second servo read element SRb, and the third servo read element SRc are arranged in that order.

[0161] The first data recording element group DWG1 has multiple first data recording elements DW1. The first data recording elements DW1 record data for the corresponding data track DT in all data tracks DT contained in the data tape DB.

[0162] Three first servo read elements SRa are provided on the first recording module DWM1. The three first servo read elements SRa are adjacent to each other in the width direction WD via multiple first data recording elements DW1. On the first recording module DWM1, the multiple first data recording elements DW1 are arranged in a straight line and are equally spaced between adjacent first servo read elements SRa.

[0163] The number of first data recording elements (DW1) contained in the first data recording element group (DWG1) is the same as the number of data tracks (DT) contained in the data tape (DB). Figure 11 In the example shown, eight first data recording elements DW1 are illustrated as multiple first data recording elements DW1, and the positions of these first data recording elements DW1 are relative to data recording playback elements DRW1, DRW2, DRW3, DRW4, DRW5, DRW6, DRW7, and DRW8 (see reference). Figure 7 and Figure 8 The position corresponds to ).

[0164] The Data Regeneration Element Group (DRG) has multiple Data Regeneration Elements (DR). Each DR regenerates data from the corresponding data track DT contained in the data tape DB.

[0165] The regeneration module DRM has three second servo read elements SRb, which are adjacent to each other in the width direction WD via multiple data regeneration elements DR. On the regeneration module DRM, the multiple data regeneration elements DR are arranged in a straight line and are equally spaced between adjacent second servo read elements SRb.

[0166] The number of data regeneration elements (DRs) contained in the data regeneration element group (DRG) is the same as the number of data tracks (DTs) contained in the data tape (DB). Figure 11 In the example shown, eight data reproducing elements (DRs) are illustrated as multiple data reproducing elements (DRs), and the positions of these data reproducing elements (DRs) are relative to data recording reproducing elements (DRW1, DRW2, DRW3, DRW4, DRW5, DRW6, DRW7, and DRW8) (see reference). Figure 7 and Figure 8 The position corresponds to ).

[0167] The second data recording element group DWG2 has multiple second data recording elements DW2. The second data recording elements DW2 record data for the corresponding data track DT in all data tracks DT contained in the data tape DB.

[0168] Three third servo read elements SRc are provided on the second recording module DWM2. The three third servo read elements SRc are adjacent to each other in the width direction WD via multiple second data recording elements DW2.

[0169] On the second recording module DMW2, multiple second data recording elements DW2 are arranged in a straight line and at equal intervals between one of the adjacent third servo reading elements SRc.

[0170] The number of secondary data recording elements (DW2) contained in the secondary data recording element group (DWG2) is the same as the number of data tracks (DT) contained in the data tape (DB). Figure 11 In the example shown, eight second data recording elements DW2 are illustrated as multiple second data recording elements DW2, and the positions of these second data recording elements DW2 are relative to data recording playback elements DRW1, DRW2, DRW3, DRW4, DRW5, DRW6, DRW7, and DRW8 (see reference). Figure 7 and Figure 8 The position corresponds to ).

[0171] Here, an example of the geometric relationship between the data recording element DW and the data playback element DR contained in the data recording and playback element DRW corresponding to a data track DT will be explained.

[0172] In the magnetic head 28 on the magnetic tape MT, the center position of the data recording element DW included in the data recording and playback element DRW corresponding to a data track DT coincides with the center position of the data playback element DR in the width direction WD. Here, the center position of the data recording element DW refers, for example, to the center position of the data recording element DW in the width direction WD. Similarly, the center position of the data playback element DR refers, for example, to the center position of the data playback element DR in the width direction WD. Furthermore, "coincidence" means, in the sense of including, errors generally permissible in the technical field to which this disclosure pertains, and errors that do not depart from the spirit of this disclosure, in addition to complete coincidence.

[0173] Furthermore, in this embodiment, the center position of the data recording element DW and the center position of the data playback element DR are aligned in the width direction WD, which is also to achieve the so-called "Read while write". In "Read while write", in order to verify whether the data recorded during the recording operation on the magnetic tape MT is recorded correctly, if the first recording module DWM1 records data on the magnetic tape MT in the forward direction according to the servo pattern signal obtained by the first servo read element SRa, then the playback module DRM immediately plays back the data. When the magnetic tape MT is transmitted in the reverse direction and the second recording module DWM2 records data on the magnetic tape MT, "Read while write" is performed between the second recording module DWM2 and the playback module DRM in the same manner.

[0174] Furthermore, in the data recording and playback element DRW corresponding to a data track DT, the length L1 of the data recording element DW in the width direction WD is longer than the length β1 of the data playback element DR in the width direction WD, and is more than twice the pitch Tp. Moreover, the length β1 is less than the pitch Tp (reference). Figure 10A and Figure 10B ).

[0175] In this embodiment, the length L1 is an example of the "recording element length" disclosed herein. Furthermore, in this embodiment, the pitch Tp is an example of the "track pitch" disclosed herein.

[0176] Based on the servo pattern signal obtained by reading the servo pattern 52 from the first servo read element SRa, the first data recording element DW1 forms a data track DT in SMR mode (reference). Figure 10A and Figure 10B After that, the data regeneration element DR extracts the segmented data track DT_N contained in the data track DT (reference). Figure 10A and Figure 10B Data is regenerated. At this time, according to the servo pattern signal obtained by reading servo pattern 52 by the second servo reading element SRb, data is regenerated from the segmented data track DT_N by the data regeneration element DR.

[0177] If the data track DT is formed using SMR (Single Recording Mode), adjacent split data tracks DT_N overlap. Therefore, when data is reproduced by the data playback element DR, the area where the data is reproduced by the data playback element DR is narrower compared to when data is recorded by the first data recording element DW1. For example, in Figure 10A and Figure 10BIn the example shown, only the region with a spacing Tp within the segmented data track DT_N becomes the data reproduction target region based on the data reproduction element DR.

[0178] The positions of the first servo read element SRa and the second servo read element SRb are aligned in the width direction WD. Therefore, when reproducing data on the data track DT formed in the SMR manner (i.e., when the data reproduction element DR reproduces data from the segmented data track DT_N), compared to when data is recorded by the first data recording element DW1, the position of the head 28 needs to be offset in the width direction WD by a distance Dr (={(length L1) - (pitch Tp)} / 2) only greater than the distance Tp. That is, the second servo read element SRb needs to read the servo pattern 52 on a path P that is offset by a distance Dr in the width direction WD from the path P through which the first servo read element SRa passes.

[0179] For example, in the case where the data is regenerated by the data regeneration element DR from a specific segmented data track DT_N formed by the data recorded by the data recording element DW, the second servo reading element SRb reads the servo pattern 52 on a path P that is offset by only a distance Dr from the path P through which the first servo reading element SRa passes along the first direction WD1.

[0180] Next, an example of a method for manufacturing magnetic tape (MT) will be described.

[0181] The manufacturing process of magnetic tape (MT) involves multiple steps. These steps include servo pattern recording, inspection, and winding. (See reference below.) Figure 12 An example of the servo pattern recording process, inspection process, and winding process will be explained.

[0182] As an example, such as Figure 12 As shown, a servo writer SW is used in the servo pattern recording process. The servo writer SW includes a tape reel SW1, a tape reel SW2, a drive unit SW3, a pulse signal generator SW4, a control unit SW5, multiple guides SW6, a transport path SW7, a servo pattern recording head WH, and a verification head VH. In this embodiment, the servo pattern recording head WH is an example of a "servo writing head" involved in the technology disclosed herein.

[0183] The control device SW5 controls the entire servo writer SW. In this embodiment, the control device SW5 is implemented using an ASIC, but the technology disclosed herein is not limited to this. For example, the control device SW5 can also be implemented using an FPGA and / or a PLC. Furthermore, the control device SW5 can also be implemented using a computer that includes a CPU, flash memory (e.g., EEPROM and / or SSD), and RAM. Moreover, it can also be implemented using a combination of two or more of ASIC, FPGA, PLC, and computer. That is, the control device SW5 can be implemented using a combination of hardware and software structures.

[0184] A disc reel is provided in the tape reel SW1. A disc reel refers to a large-diameter tape MT that is cut from a wide roll to the product width and wound onto a hub before the servo pattern 52 is written.

[0185] The drive unit SW3 has a motor (not shown) and gears (not shown), and is mechanically connected to the feed reel SW1 and the take-up reel SW2. When the tape MT is wound by the take-up reel SW2, the drive unit SW3 generates power according to the instruction from the control unit SW5, and transmits the generated power to the feed reel SW1 and the take-up reel SW2, thereby causing the feed reel SW1 and the take-up reel SW2 to rotate.

[0186] That is, the feed reel SW1 receives power from the drive unit SW3 and rotates, thereby feeding the magnetic tape MT onto the predetermined transport path SW7. The reel SW2 receives power from the drive unit SW3 and rotates, thereby winding the magnetic tape MT fed from the feed reel SW1. The rotational speed and rotational torque of the feed reel SW1 and the reel SW2 are adjusted according to the speed at which the reel SW2 winds the magnetic tape MT.

[0187] Multiple guides SW6 and a servo pattern recording head WH are configured on the transport path SW7. The servo pattern recording head WH is positioned on the surface 31 side of the magnetic tape MT between the multiple guides SW6. The magnetic tape MT fed from the feed reel SW1 to the transport path SW7 is guided by the multiple guides SW6 and wound onto the reel SW2 via the servo pattern recording head WH.

[0188] Under the control of the control device SW5, the pulse signal generator SW4 generates pulse signals and supplies them to the servo pattern recording head WH. With the magnetic tape MT traveling at a predetermined speed along the transport path SW7, the servo pattern recording head WH, according to the pulse signals supplied from the pulse signal generator SW4, moves along the length direction LD (reference) to the pre-determined area for forming the servo tape SB. Figure 6 (etc.) Record multiple servo patterns 52, thereby forming a servo tape SB on the magnetic tape MT.

[0189] The inspection process is a process of inspecting the magnetic tape MT on which the servo tape SB is formed. For example, in the inspection process, the servo tape SB formed by the servo pattern recording head WH on the surface 31 of the magnetic tape MT is inspected. The inspection of the servo tape SB refers, for example, to the process of determining whether the servo pattern 52 recorded on the servo tape SB is correct. The determination of whether the servo pattern 52 is correct refers, for example, to determining whether the magnetization lines 54A1a, 54A2a, 54B1a, and 54B2a at predetermined locations within the surface 31 have recorded the servo patterns 52A and 58B without over- or under-recording and within the allowable error (i.e., verification of the servo pattern 52).

[0190] The inspection of the servo tape SB is performed using the control device SW5 and the verification head VH. The verification head VH is positioned downstream of the servo pattern recording head WH in the transport direction of the magnetic tape MT. The verification head VH, like the magnetic head 28, is equipped with multiple servo read elements (not shown), and these multiple servo read elements read multiple servo tapes SB.

[0191] The verification head VH is connected to the control device SW5. The verification head VH is positioned so that it faces the servo tape SB when viewed from the surface 31 side of the magnetic tape MT (i.e., the back side of the verification head VH), and reads the servo pattern 52 recorded on the servo tape SB, outputting the read result (hereinafter referred to as the "servo pattern read result") to the control device SW5. The control device SW5 checks the servo tape SB (e.g., determines whether the servo pattern 52 is correct) based on the servo pattern read result (e.g., servo pattern signal) input from the verification head VH.

[0192] The control device SW5 outputs information indicating the inspection result of the servo band SB (e.g., the determination result of whether the servo pattern 52 is correct) to a predetermined output object (e.g., a storage device built into the servo writer SW, a display connected to the servo writer SW, and / or an external device that can communicate with the servo writer SW).

[0193] If the inspection process is completed (for example, if the inspection process determines that the servo tape SB is correctly formed on the magnetic tape MT), then the winding process is performed. The winding process involves winding the magnetic tape onto multiple tape cassettes 12 (see reference). Figures 1-4 Each uses a tape reel 22 (i.e., a tape cassette 12 (see reference)). Figures 1-4 The feed tray 22 in the ) (reference) Figures 2-4The winding process involves a tape reel motor M. The tape reel motor M is mechanically connected to the feed reel 22 via gears, etc. Under the control of a control device (not shown), the tape reel motor M imparts rotational force to the feed reel 22, thereby causing the feed reel 22 to rotate. The magnetic tape MT wound onto the feed reel 22 is wound onto the feed reel 22 by the rotation of the feed reel 22. A cutting device (not shown) is used in the winding process. If the required amount of magnetic tape MT is wound onto each of the multiple feed reels 22, the magnetic tape MT fed from the feed reel 22 to the feed reel 22 is cut by the cutting device.

[0194] exist Figure 13 The diagram shows the transmission path SW7 (reference). Figure 12 An example of the structure of the servo pattern recording head WH when observing the surface 31 side of the magnetic tape MT (i.e., the back side of the servo pattern recording head WH), and an example of the structure of the pulse signal generator SW4.

[0195] As an example, such as Figure 13 As shown, the servo pattern recording head WH has a base WH1 and multiple magnetic head cores WH2. The base WH1 is formed into a cuboid shape and is arranged to span the surface 31 of the magnetic tape MT traveling on the transport path SW7 along the width direction WD. The surface WH1A of the base WH1 is a rectangle with a long side WH1Aa and a short side WH1Ab, and the long side WH1Aa spans the surface 31 of the magnetic tape MT along the width direction WD.

[0196] Surface WH1A has a sliding surface WH1Ax. The sliding surface WH1Ax is the surface of surface WH1A that overlaps with surface 31 of magnetic tape MT when the substrate WH1 spans across surface 31 of magnetic tape MT in the width direction WD. The sliding surface WH1Ax slides relative to magnetic tape MT in the tape-running state. Figure 13 The width of the sliding surface WH1Ax shown (i.e., the length in the direction LD1 corresponding to the length direction LD (e.g., the same direction as the length direction LD)) is only one example; the width of the sliding surface WH1Ax can also be greater than... Figure 13 The example shown is several times wider.

[0197] The length direction of the substrate WH1, i.e., direction WD3 (i.e., the direction along the long side WH1Aa), is the direction corresponding to the width direction WD (e.g., the same direction as the width direction WD). Multiple magnetic head cores WH2 are assembled in the substrate WH1 along direction WD3. On the surface WH1A of the magnetic head cores WH2 (i.e., the side of the substrate WH1 opposite to the surface 31 of the magnetic tape MT), multiple gap patterns G are formed at intervals along direction WD3.

[0198] In this embodiment, direction WD3 is an example of the "second length direction" disclosed herein. Furthermore, in this embodiment, surface WH1A is an example of the "opposing surface" disclosed herein. And, in this embodiment, gap pattern G is an example of the "gap pattern" disclosed herein.

[0199] The gap pattern G consists of a pair of non-parallel straight line regions. For example, a pair of non-parallel straight line regions refers to regions that are parallel to each other. Figure 6 The linear magnetization region 54A1 shown contains a region of lines with the same geometric characteristics as the uppermost magnetization line 54A1a in the positive direction among the five magnetization lines 54A1a. Figure 6 The linear magnetization region 54A2 shown contains a region of linear magnetization lines 54A2a, the uppermost magnetization line 54A2a in the positive direction, which has the same geometric characteristics as the line region.

[0200] On surface WH1A, multiple gap patterns G are formed at intervals along direction WD3. On surface WH1A, the interval in direction WD3 between adjacent gap patterns G in direction WD3 corresponds to the interval in the width direction WD between servo tapes SB of magnetic tape MT (i.e., servo tape spacing).

[0201] A coil (not shown) is wound on the magnetic head core WH2, and a pulse signal is supplied to the coil. The pulse signal supplied to the coil is the pulse signal used for servo pattern 52A and the pulse signal used for servo pattern 52B.

[0202] In the case of a servo pattern recording process performed by a servo writer SW configured as described above, the servo pattern recording head WH is positioned with the surface 31 of the magnetic tape MT facing multiple gap patterns G. Then, while maintaining this position, the servo writing head WH records multiple servo patterns G along the length direction LD on the surface 31 of the magnetic tape MT, thereby forming multiple servo tapes SB on the surface 31 (see reference). Figure 6 The method for forming multiple servo bands SB on surface 31 will be described in more detail below.

[0203] If a pulse signal for servo pattern 52A is supplied to the coil of the magnetic head core WH2 when the gap pattern G is opposite to (in other words, facing each other) a predetermined area on the surface 31 of the magnetic tape MT traveling on the transport path SW7 for forming the servo tape SB, a magnetic field is applied to the servo tape SB of the magnetic tape MT from the gap pattern G according to the pulse signal. Thus, the servo pattern 52A is recorded in the predetermined area on the surface 31 of the magnetic tape MT for forming the servo tape SB. Furthermore, if a pulse signal for servo pattern 52B is supplied to the coil of the magnetic head core WH2 when the gap pattern G is opposite to (in other words, facing each other) a predetermined area on the surface 31 of the magnetic tape MT for forming the servo tape SB, a magnetic field is applied to the servo tape SB of the magnetic tape MT from the gap pattern G. Thus, the servo pattern 52B is recorded in the predetermined area on the surface 31 of the magnetic tape MT for forming the servo tape SB. Thus, in the area predetermined for forming the servo tape SB within the surface 31 of the magnetic tape MT, servo patterns 52A and 52B are alternately formed along the length direction, thereby forming the servo tape SB.

[0204] For each servo pattern 52 (i.e., each frame 50 (reference) Figure 6 The pulse signal corresponding to the servo pattern 52A is modulated. Various information is embedded within the pulse signal through modulation. In this case, for example, by modulating the pulse signal used for servo pattern 52A, it is possible to change five magnetization lines 54A1a (see reference) for each servo pattern 52A. Figure 6 The interval between the third magnetization line 54A1a and the second magnetization line 54A1a (hereinafter referred to as the "first interval"), and the interval between the third magnetization line 54A1a and the fourth magnetization line 54A1a (hereinafter referred to as the "second interval") in the servo pattern 52A. By making the first interval and the second interval different for each servo pattern 52A, at least one bit of information can be embedded into each servo pattern 52A. Thus, various types of information can be embedded by combining multiple servo patterns 52.

[0205] Various types of information include, for example, information related to the position of the tape MT in the length direction LD, information identifying the servo tape SB, and / or information identifying the manufacturer of the tape MT, etc.

[0206] exist Figure 13 In the example shown, head cores WH2A, WH2B, and WH2C are shown as examples of multiple head cores WH2, and gap patterns G1, G2, and G3 are shown as examples of multiple gap patterns G. Gap pattern G1 is formed in head core WH2A. Gap pattern G2 is formed in head core WH2B. Gap pattern G3 is formed in head core WH2C.

[0207] Gap patterns G1 to G3 each have the same geometric characteristics. In this embodiment, for example, gap pattern G1 is used for the servo band SB3 (reference). Figure 6 Record servo pattern 52 (reference) Figure 6 The gap pattern G2 is used for the servo band SB2 (reference). Figure 6 Record servo pattern 52 (reference) Figure 6 The gap pattern G3 is used for servo band SB1 (reference). Figure 6 Record servo pattern 52 (reference) Figure 6 ).

[0208] Gap pattern G1 is a pair of straight line regions formed by straight line regions G1A and G1B. Gap pattern G2 is a pair of straight line regions formed by straight line regions G2A and G2B. Gap pattern G3 is a pair of straight line regions formed by straight line regions G3A and G3B. In this embodiment, gap patterns G1 to G3 are examples of the "multiple gap patterns" disclosed herein.

[0209] The pulse signal generator SW4 includes a first pulse signal generator SW4A, a second pulse signal generator SW4B, and a third pulse signal generator SW4C. The first pulse signal generator SW4A is connected to the magnetic head core WH2A. The second pulse signal generator SW4B is connected to the magnetic head core WH2B. The third pulse signal generator SW4C is connected to the magnetic head core WH2C.

[0210] The gap pattern G1 is used to form the servo band SB3 (reference). Figure 6 In the case where the first pulse signal generator SW4A supplies a pulse signal to the magnetic head core WH2A, a magnetic field is applied from the gap pattern G1 to the predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB3 according to the pulse signal, thereby recording the servo pattern 52 (see reference) in the predetermined area for forming the servo tape SB3. Figure 6 ).

[0211] For example, if a pulse signal for servo pattern 52A is supplied to the magnetic head core WH2A when the gap pattern G1 is facing (in other words, directly opposite) a predetermined area on the surface 31 of the magnetic tape MT that is traveling on the conveyor path SW7 for forming servo tape SB3, then servo pattern 52A is recorded in the predetermined area on the surface 31 of the magnetic tape MT for forming servo tape SB3 (see reference). Figure 6 That is, in the area predetermined for forming the servo tape SB3 within the surface 31 of the magnetic tape MT, the linear magnetization region 54A1 is recorded through the linear region G1A (see reference). Figure 6Furthermore, the linear magnetization region 54A2 is recorded in the servo band SB3 via the linear region G1B (see reference). Figure 6 Thus, a servo pattern 52A is formed in a predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB3.

[0212] Furthermore, for example, if a pulse signal for the servo pattern 52B is supplied to the magnetic head core WH2A when the gap pattern G1 is facing (in other words, directly opposite) a predetermined area on the surface 31 of the magnetic tape MT that is traveling on the transport path SW7 for forming the servo tape SB3, then the servo pattern 52B is recorded in the predetermined area on the surface 31 of the magnetic tape MT for forming the servo tape SB1 (see reference). Figure 6 That is, in the area predetermined for forming the servo tape SB1 within the surface 31 of the magnetic tape MT, the linear magnetization region 54B1 is recorded through the linear region G1A (see reference). Figure 6 Furthermore, in the area predetermined for forming the servo tape SB3 within the surface 31 of the magnetic tape MT, the linear magnetization region 54B2 is recorded through the linear region G1B (see reference). Figure 6 Thus, a servo pattern 52B is formed in a predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB3.

[0213] Thus, in the area predetermined for forming the servo tape SB3 within the surface 31 of the magnetic tape MT, servo patterns 52A and 52B are alternately formed along the length direction LD, thereby forming the servo tape SB3.

[0214] The gap pattern G2 is used to form the servo band SB2 (reference). Figure 6 In the case where the second pulse signal generator SW4B supplies a pulse signal to the magnetic head core WH2B, a magnetic field is applied from the gap pattern G2 to a predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB2, thereby recording the servo pattern 52 (see reference) within the predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB2. Figure 6 ).

[0215] For example, if a pulse signal for servo pattern 52A is supplied to the magnetic head core WH2B when the gap pattern G2 is facing (in other words, directly opposite) a predetermined area on the surface 31 of the magnetic tape MT that is traveling on the conveyor path SW7 for forming servo tape SB2, then servo pattern 52A is recorded in the predetermined area on the surface 31 of the magnetic tape MT for forming servo tape SB2 (see reference). Figure 6That is, in the predetermined region within the surface 31 of the magnetic tape MT for forming the servo tape SB2, the linear magnetization region 54A1 is recorded through the straight region G2A, and in the predetermined region within the surface 31 of the magnetic tape MT for forming the servo tape SB2, the linear magnetization region 54A2 is recorded through the straight region G2B (see reference). Figure 6 Thus, a servo pattern 52A is formed in a predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB2.

[0216] Furthermore, for example, if the gap pattern G2 is opposite to (in other words, facing each other) a predetermined area for forming the servo tape SB2 on the surface 31 of the magnetic tape MT traveling on the transport path SW7, and a pulse signal for supplying the servo pattern 52B to the magnetic head core WH2B, then the servo pattern 52B is recorded in the predetermined area for forming the servo tape SB2 on the surface 31 of the magnetic tape MT. That is, in the predetermined area for forming the servo tape SB2 on the surface 31 of the magnetic tape MT, the linear magnetization area 54B1 is recorded through the straight area G2A, and in the predetermined area for forming the servo tape SB2 on the surface 31 of the magnetic tape MT, the linear magnetization area 54B2 is recorded through the straight area G2B (see reference). Figure 6 Thus, a servo pattern 52B is formed in a predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB2.

[0217] Thus, in the area predetermined for forming the servo tape SB2 within the surface 31 of the magnetic tape MT, servo patterns 52A and 52B are alternately formed along the length direction LD, thereby forming the servo tape SB2.

[0218] In the gap pattern G3, the servo band SB1 is formed (reference). Figure 6 In the case where the third pulse signal generator SW4C supplies a pulse signal to the magnetic head core WH2C, a magnetic field is applied from the gap pattern G3 to the predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB1, according to the pulse signal, thereby recording the servo pattern 52 (see reference) within the predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB1. Figure 6 ).

[0219] For example, if a pulse signal for the servo pattern 52A is supplied to the magnetic head core WH2C when the gap pattern G3 is opposite to (in other words, facing each other) a predetermined area on the surface 31 of the magnetic tape MT that is traveling on the transport path SW7 for forming the servo tape SB1, then the servo pattern 52A is recorded in the predetermined area on the surface 31 of the magnetic tape MT for forming the servo tape SB1. That is, in the predetermined area on the surface 31 of the magnetic tape MT for forming the servo tape SB1, a linear magnetization region 54A1 is recorded through the linear region G3A (see reference). Figure 6 Furthermore, in the area predetermined for forming the servo tape SB1 within the surface 31 of the magnetic tape MT, a linear magnetization region 54B2 is recorded via a linear region G3B (see reference). Figure 6 Thus, a servo pattern 52A is formed in a predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB1.

[0220] Furthermore, for example, if a pulse signal for the servo pattern 52B is supplied to the magnetic head core WH2C when the gap pattern G3 is facing (in other words, directly opposite) a predetermined area on the surface 31 of the magnetic tape MT that is traveling on the transport path SW7 for forming the servo tape SB1, then the servo pattern 52B is recorded in the predetermined area on the surface 31 of the magnetic tape MT for forming the servo tape SB1. That is, in the predetermined area on the surface 31 of the magnetic tape MT for forming the servo tape SB1, a linear magnetization region 54B1 is recorded through a straight region G3A (see reference). Figure 6 Furthermore, in the area predetermined for forming the servo tape SB1 within the surface 31 of the magnetic tape MT, a linear magnetization region 54B2 is recorded via a linear region G3B (see reference). Figure 6 Thus, a servo pattern 52B is formed in a predetermined area within the surface 31 of the magnetic tape MT for forming the servo tape SB1.

[0221] Thus, in the area predetermined for forming the servo tape SB1 within the surface 31 of the magnetic tape MT, servo patterns 52A and 52B are alternately formed along the length direction LD, thereby forming the servo tape SB1.

[0222] The magnetic head core WH2C has a magnetic film 60 and a substrate glass 62. The magnetic film 60 forms the substrate of the magnetic head core WH2C. As an example of the magnetic film 60, a metal film can be cited. Here, the concept of "metal film" also includes alloy films. As an example of a metal film, a deposited film formed by stacking one or more metal materials selected from the group consisting of one or more pure metals and one or more alloys can be cited. Furthermore, the metal film may contain one or more additives, and may also contain one or more impurities that are inevitably mixed in. The magnetic film 60 can be an iron-based alloy film. Here, "based" means "includes". An iron-based alloy film is preferably an iron-nitride alloy film. As an example of an iron-nitride alloy, as a constitutive element, one or two or more constitutive elements selected from the group consisting of Al and / or Ta, along with Fe and N, can be cited. The magnetic film 60 can also be obtained as a deposited film formed by depositing metallic material on a substrate using known film deposition methods such as physical vapor deposition (PVD) and / or chemical vapor deposition (CVD), such as sputtering and / or vacuum evaporation. The substrate glass 62, together with the magnetic film 60, forms the substrate of the WH2C magnetic head core. A non-magnetic material is used in the substrate glass 62. A plane 66 is formed by the magnetic film 60 and the substrate glass 62.

[0223] A linear opening 66A is formed on a substrate glass 62, and a non-magnetic material 68, such as silicon dioxide and / or aluminum, is filled into the opening 66A to form a substrate G3B1. The substrate G3B1 is the substrate of the linear region G3B.

[0224] The magnetic head core WH2C is formed using photolithography. If the substrate G3B1, which has low straightness in the ridge region 70, is directly used as the straight region G3B, it will be difficult to record a highly straight servo pattern 52 on the surface 31 of the magnetic tape MT. If the straightness of the servo pattern 52 decreases, the accuracy of servo control will decrease.

[0225] As methods to improve the straightness of the edge region 70, the following methods 1 to 3 can be listed as examples. The first method is to improve the straightness of the edge region 70 by increasing the precision of the photomask used in photolithography. The second method is as follows: using FIB or a laser to trim the full width of the opening 66A of the magnetic head core WH2C formed by photolithography, thereby forming a straight groove 71 with a size corresponding to the full width of the opening 66A, and filling the groove 71 with a non-magnetic material 68, thereby forming a straight region G3B. The third method is as follows: using FIB or a laser to trim the edge region 70 of the substrate G3B1 of the magnetic head core WH2C formed by photolithography into a straight shape, thereby forming a groove 72, and filling the groove 72 with a non-magnetic material 68, thereby forming a straight region G3B.

[0226] Regarding the third method, for example, firstly, the magnetic head core WH2C formed by photolithography is processed using FIB or laser to shape the substrate G3B1. Specifically, the edge region 70 of the substrate G3B1 of the magnetic head core WH2C formed by photolithography is irradiated with FIB or laser along the length direction of the substrate G3B1, thereby straightening the edge region 70 of the substrate G3B1 into a straight line. Then, a non-magnetic material 68 is filled into the groove 72 obtained by straightening the substrate G3B1 using FIB. Thus, a straight region G3B is formed by shaping the substrate G3B1. Therefore, by performing processing using any of the methods from the first to the third method, the straightness of the straight region G3B can be improved, and the durability of the straight region G3B can be improved.

[0227] Furthermore, while a straight line region G3B is illustrated here, straight line regions G1A, G1B, G2A, G2B, and G3A can also be obtained by performing the same processing as that performed to obtain straight line region G3B.

[0228] Thus, by processing the magnetic head core WH2 using FIB or laser, the straightness of the straight areas G1A, G1B, G2A, G2B, G3A and G3B is improved. As a result, multiple servo patterns 52 with high straightness can be formed on the surface 31 of the magnetic tape MT for each servo tape SB along the length direction LD.

[0229] In this embodiment, in order to further improve the linearity of each servo pattern 52 contained in each servo band SB, as an example, such as Figure 14 As shown, a linearity check method is performed on a magnetic tape MT having multiple servo tapes SB.

[0230] The straightness inspection method is a method for checking the straightness of the servo pattern 52 formed on the magnetic tape MT, and is implemented, for example, in the inspection process included in the aforementioned magnetic tape MT manufacturing method. Alternatively, this is just one example; the inspection using the straightness inspection method can also be performed using the magnetic tape drive 14. The straightness inspection method can be implemented through manual measurement or other operations mainly performed by an inspector (not shown), or it can be implemented through automation mainly using an inspection device (not shown). In this embodiment, Figure 14 The linearity check method shown is an example of the "check method" involved in the technology disclosed herein.

[0231] exist Figure 14In the linearity checking method shown, firstly, in step ST10, from the two servo tapes SB that span one servo tape SB in the width direction WD of the magnetic tape MT formed by the above-mentioned servo pattern recording process (that is, a pair of servo tapes SB that are not adjacent in the width direction WD, i.e., servo tape SB1 and servo tape SB3), a pair of unchecked servo patterns 52 that are adjacent in the width direction WD are selected (i.e., a pair of servo patterns 52 that have not been checked for linearity).

[0232] In the next step ST12, an index (hereinafter also referred to as "index") representing the nonlinearity of the servo pattern 52 is obtained from the pair of unchecked servo patterns 52 selected in step ST10.

[0233] In the next step ST14, the tape MT is checked using the metrics obtained in step ST12. For example, in step ST14, the linearity of the unchecked pair of servo patterns 52 selected in step ST10 is checked using the metrics obtained in step ST12.

[0234] In the next step ST16, it is determined whether the straightness of all inspection objects (i.e., all pairs of servo patterns 52 predetermined as inspection objects) contained in the two servo tapes SB that span one servo tape SB in the width direction WD within the magnetic tape MT has been checked. If, in step ST16, the straightness of all inspection objects contained in the two servo tapes SB that span one servo tape SB in the width direction WD within the magnetic tape MT has not been checked, a negative determination is made, and the straightness inspection method proceeds to step ST10. If, in step ST16, the straightness of all inspection objects contained in the two servo tapes SB that span one servo tape SB in the width direction WD within the magnetic tape MT has been checked, a positive determination is made, and the straightness inspection method ends. Furthermore, an example of checking the straightness of all inspection objects contained in the two servo tapes SB that span one servo tape SB in the width direction WD within the magnetic tape MT is given here, but this is only one example. For example, in the case of a servo belt (illustrated but referred to as "servo belt SB4") that spans more than one data belt (not shown) in the first direction WD1 side compared to servo belt SB3, the straightness of all the inspection objects (i.e., all pairs of servo patterns 52 predetermined as inspection objects) contained in servo belt SB2 and servo belt SB4 can be further checked.

[0235] Here, a specific example of how to derive the index is explained.

[0236] The index utilizes multiple PES. PES refers to the position of the width direction WD within the servo pattern 52. PES is measured using the following formula (1).

[0237] [Formula 1] exist Figure 15 The diagram shows a conceptual diagram of the variable used in Equation (1) to determine the PES and PES of the linear magnetized region 54A1 within the servo pattern 52A when the magnetic tape MT is traveling in the forward direction.

[0238] In equation (1), "α1" is a predetermined angle formed by the virtual straight line C1 and the linear magnetized region 54A1. In equation (1), "α2" is a predetermined angle formed by the virtual straight line C1 and the linear magnetized region 54A2. Furthermore, in this embodiment, since the linear magnetized regions 54A1 and 54A2 are symmetrically inclined with respect to the virtual straight line C1, "α1" and "α2" are the same value.

[0239] In equation (1), "i" is a natural number from 1 to 4. The maximum value of "i" (4 in this case) is the number of magnetization lines 54A1a used in the PES measurement. In equation (1), "Ai" refers to the distance between magnetization lines 54A1a and 54A2a at corresponding positions when the servo reading element SR4 of the verification head VH crosses the servo pattern 52A along the length direction LD. Here, "magnetization lines 54A1a and 54A2a at corresponding positions" refers to the first to fourth pairs of magnetization lines. The first pair of magnetization lines refers to the magnetization lines 54A1a and 54A2a located on the upstream side of the magnetic tape MT in the tape transport direction of each of the linear magnetization regions 54A1 and 54A2. The second pair of magnetization lines refers to magnetization lines 54A1a and 54A2a located at the second position from the upstream side to the downstream side in the direction of tape MT in both linear magnetization regions 54A1 and 54A2. The third pair of magnetization lines refers to magnetization lines 54A1a and 54A2a located at the third position from the upstream side to the downstream side in the direction of tape MT in both linear magnetization regions 54A1 and 54A2. The fourth pair of magnetization lines refers to magnetization lines 54A1a and 54A2a located at the fourth position from the upstream side to the downstream side in the direction of tape MT in both linear magnetization regions 54A1 and 54A2.

[0240] In equation (1), "Bi" refers to the distance between the magnetized lines 54A1a and 54B1a at corresponding positions when the servo read element SR4 crosses the servo pattern 52A and the servo pattern 52B adjacent to the servo pattern 52A on the positive side along the length direction LD. Here, "magnetized lines 54A1a and 54B1a at corresponding positions" refers to the 5th to 8th pairs of magnetized lines. The 5th pair of magnetized lines refers to the magnetized lines 54A1a and 54B1a located on the upstream side of the magnetic tape MT in the tape transport direction of the linear magnetized region 54A1 in the servo pattern 52A and the linear magnetized region 54B1 in the servo pattern 52B adjacent to the servo pattern 52A on the positive side. The sixth pair of magnetization lines refers to the magnetization lines 54A1a and 54B1a located at the second position from the upstream side to the downstream side in the tape transport direction of the magnetic tape MT, in both the linear magnetization region 54A1 within the servo pattern 52A and the linear magnetization region 54B1 within the servo pattern 52B adjacent to the servo pattern 52A on the positive side. The seventh pair of magnetization lines refers to the magnetization lines 54A1a and 54B1a located at the third position from the upstream side to the downstream side in the tape transport direction of the magnetic tape MT, in both the linear magnetization region 54A1 within the servo pattern 52A and the linear magnetization region 54B1 within the servo pattern 52B adjacent to the servo pattern 52A on the positive side. The 8th pair of magnetization lines refers to the magnetization lines 54A1a and 54B1a located at the 4th position from the upstream side to the downstream side in the direction of the tape MT, in the linear magnetization region 54A1 in the servo pattern 52A and the linear magnetization region 54B1 in the servo pattern 52B adjacent to the servo pattern 52A on the positive side.

[0241] In equation (1), "d" is a predetermined distance that serves as the distance between linear magnetized regions 54A1 and 54B1 along the length direction LD. As an example of "d", the predetermined distance can be given as the distance between magnetized lines 54A1a and 54B1a, which are corresponding positions, when the servo read element SR4 crosses the servo patterns 52A and 52B along the length direction LD.

[0242] Furthermore, here is an example of using formula (1) to measure the PES in the servo pattern 52A when the magnetic tape MT is traveling in the forward direction. Formula (1) can also be used to measure the PES in the servo pattern 52B. In this case, "Bi" refers to the distance between the magnetization lines 54B1a and 54A1a at the corresponding positions when the servo read element SR4 crosses the servo pattern 52B and the servo pattern 52A adjacent to the servo pattern 52B on the forward side along the length direction LD.

[0243] "Ai" and "Bi" are determined based on the servo pattern signal, which is obtained by reading the servo pattern 52 by the servo reading element SR4 of the verification head VH.

[0244] Regarding PES, when the center position of the servo pattern 52 in the width direction WD (for example, the position where the virtual straight line C3, which passes through the center of the servo pattern 52 in the width direction WD along the length direction LD, intersects the servo pattern 52) is set to "0", the position in the servo pattern 52 located on the first direction WD1 side compared to the virtual straight line C3 is displayed as a positive value, and the position in the servo pattern 52 located on the second direction WD2 side compared to the virtual straight line C3 is displayed as a negative value.

[0245] As an example, such as Figure 16 As shown, in the servo pattern recording process described above, a pair of servo patterns 52 that are adjacent in the width direction WD within two servo tapes SB that cross one servo tape SB in the width direction WD within the magnetic tape MT containing multiple servo tapes SB (here, servo tapes SB1 and SB3 are examples of servo tapes SB1 and SB3, which are not adjacent in the width direction WD) are read by the servo readout element SR4 used for each servo tape SB (here, servo tapes SB1 and SB3, which are examples of servo tapes SB1 and SB3, respectively). Then, multiple dPES are measured based on the servo pattern signals obtained by reading each servo pattern 52 (here, each of the pair of servo patterns 52 that are adjacent in the width direction WD contained in servo tapes SB1 and SB3, which are examples of servo tapes SB1 and SB3, respectively).

[0246] Furthermore, for ease of explanation, the two servo tapes SB that cross one servo tape SB in the width direction WD within the magnetic tape MT, which has multiple servo tapes SB formed through the above-described servo pattern recording process (i.e., two servo tapes SB that are not adjacent in the width direction WD within the magnetic tape MT, which has multiple servo tapes SB formed through the above-described servo pattern recording process) will also be referred to as a "servo tape pair". And, for ease of explanation, the pair of servo patterns 52 that are adjacent in the width direction WD within the servo tape pair will also be referred to as a "servo pattern pair".

[0247] If one of the servo patterns 52 contained in the servo pattern pair (for example, ...) is to be included in the servo pattern pair, Figure 16 The PES for measuring the upper servo pattern 52 shown is set as PES1, and the PES for measuring the other servo pattern 52 included in the servo pattern pair (e.g., Figure 16If the PES measured for the servo pattern 52 shown on the lower side is set as PES2, then the difference between PES1 and PES2, i.e., dPES, can be measured. When the tape MT does not deform in the width direction WD, the linearity of the servo pattern 52 is ideal, and the spacing between the two servo read elements SR4 (hereinafter also referred to as "servo read element pair") used on the servo tape pair is at the design center, dPES becomes "0".

[0248] During the inspection process, the straightness of the servo pattern 52 needs to be checked. Multiple PES and multiple dPES are measured at multiple positions from one end of the servo pattern 52 (here, the end on the WD1 side in the first direction, for example) to the other end (here, the end on the WD2 side in the second direction, for example), as detailed later. Then, ΔdPES, which is the PES difference gap, is measured based on the multiple PES and multiple dPES.

[0249] In one servo pattern 52 and another servo pattern 52, multiple first positions 74 and multiple second positions 76 are set. A servo pattern 52 refers to one servo pattern 52 contained in a pair of servo pattern pairs recorded on the servo tape pair at corresponding positions in the width direction WD. Figure 16 The upper servo pattern 52 is shown. The other servo pattern 52 refers to another servo pattern 52 included in the servo pattern pair recorded on the servo tape pair at corresponding positions in the width direction WD, i.e. Figure 16 The servo pattern 52 shown on the lower side.

[0250] In a linear magnetization region 54A1 (e.g., the magnetization line 54A1a located on the uppermost side in the positive direction) included in a servo pattern 52, a plurality of first positions 74 and a plurality of second positions 76 are set from one end (e.g., the end on the side of the first direction WD1) to the other end (e.g., the end on the side of the second direction WD2) of the linear magnetization region 54A1. The plurality of first positions 74 and the plurality of second positions 76 are in a predetermined correspondence. The first positions 74 and second positions 76, which are in a corresponding position relationship, are set on the linear magnetization region 54A1 at intervals INT1 along the width direction WD. Furthermore, the first positions 74 and second positions 76, which are in a corresponding position relationship, are each set on the linear magnetization region 54A1 at intervals INT2 along the width direction WD. The interval INT1 is approximately equivalent to the distance Dr described above (refer to...). Figure 11 The interval INT1 is approximately equal to the distance Dr, and the interval INT2 is approximately equal to the distance Tp. In this embodiment, for ease of explanation, the explanation is based on the premise that "interval INT1 = distance Dr" and "interval INT2 = distance Tp".

[0251] This is just one example; even if "interval INT1 ≈ distance Dr" and "interval INT2 ≈ spacing Tp", the disclosed technique still holds true. In this embodiment, interval INT1 is an example of the "first predetermined interval" involved in the disclosed technique. Interval INT2 is an example of the "second predetermined interval" involved in the disclosed technique.

[0252] Between interval INT1 and spacing Tp, the relationship "interval INT1 > spacing Tp" holds true. Furthermore, between interval INT1 and interval INT2, the relationship "interval INT1 > interval INT2" holds true. Also, interval INT1 is the interval closest to the reference interval. The reference interval is defined as an interval that is a natural multiple of interval INT2 (e.g., a natural multiple of 2 or greater), and is equivalent to length L1 (see reference). Figure 11 The interval is half the difference between the spacing INT1 and the spacing Tp. Here, as an example of spacing INT1, 1200 nm is used, and as an example of spacing INT2, 400 nm is used.

[0253] exist Figure 16 In the example shown, when the variable n is set to a natural number greater than or equal to 3, dPES is roughly divided into dPES(n) and dPES(n-3). In this embodiment, dPES(n-3) is an example of the "first PES difference" involved in the disclosed technology. Furthermore, in this embodiment, dPES(n) is an example of the "second PES difference" involved in the disclosed technology.

[0254] In linearity checking methods (e.g., Figure 14 In step ST12 of the linearity checking method shown, dPES(n-3) is measured using the PES of one first position 74 and the PES of the other first position 74 in a pair of corresponding positions in the servo pattern pair. More specifically, dPES(n-3) is measured using the PES of one first position 74 and the PES of the other first position 74 in a pair of corresponding first positions 74 between a linear magnetized region 54A1 (e.g., the magnetized straight line 54A1a on the positive upstream side) included in one servo pattern 52 and a linear magnetized region 54A1 (e.g., the magnetized straight line 54A1a on the positive upstream side) included in another servo pattern 52.

[0255] In linearity checking methods (e.g., Figure 14In step ST12 of the linearity checking method shown, dPES(n) is measured using the PES of one second position 76 and the PES of the other second position 76 in a pair of corresponding second positions 76 in the servo pattern pair. More specifically, dPES(n) is measured using the PES of one second position 76 and the PES of the other second position 76 in a pair of corresponding second positions 76 between a linear magnetized region 54A1 (e.g., the magnetized straight line 54A1a on the positive upstream side) included in one servo pattern 52 and a linear magnetized region 54A1 (e.g., the magnetized straight line 54A1a on the positive upstream side) included in another servo pattern 52.

[0256] In linearity checking methods (e.g., Figure 14 In step ST12) of the linearity inspection method shown, multiple ΔdPES are measured based on multiple dPES(n-3) and multiple dPES(n). ΔdPES is the difference between corresponding dPES(n-3) and dPES(n). Corresponding dPES(n-3) and dPES(n) refer to dPES(n-3) and dPES(n) at the first position 74 and the second position 76, which are separated by an interval INT1 along the width direction WD. In this embodiment, ΔdPES is an example of the "PES difference gap" involved in the disclosed technology.

[0257] In this embodiment, the interval INT2 is set to one step size, and the variable n corresponds to the measurement step size. In this embodiment, 1200 nm is used as an example of the interval INT1, and 400 nm is used as an example of the interval INT2. ΔdPES is calculated using the dPES values ​​of positions separated by only "3" measurement steps, where "3" measurement steps represent the ratio of interval INT2 to interval INT1 (in other words, the ratio). The variable n is incremented by 1 each time the first position 74 and the second position 76 advance one measurement step along the second direction WD2. That is, whenever the first position 74 and the second position 76 move an interval INT2 along the second direction WD2, the variable n is incremented by 1, thereby updating a pair of first positions 74 and a pair of second positions 76. If a pair of first positions 74 and a pair of second positions 76 are updated, dPES(n-3) is measured for the updated pair of first positions 74, and dPES(n) is measured for the updated pair of second positions 76. Then, each time dPES(n-3) and dPES(n) are measured, ΔdPES (i.e., the difference between dPES(n-3) and dPES(n)) is determined based on the measured dPES(n-3) and dPES(n).

[0258] Thus, in Figure 16In the example shown, in the servo pattern pair, for a pair of adjacent linear magnetized regions 54A1 in the width direction WD, ΔdPES is measured every interval INT2 along the second direction WD2, thereby obtaining multiple ΔdPES.

[0259] Furthermore, in the same manner as setting multiple first positions 74 and multiple second positions 76 on a pair of linear magnetization regions 54A1 included in the servo pattern pair, multiple first positions 74 and multiple second positions 76 are also set on a pair of linear magnetization regions 54A2 included in the servo pattern pair (for example, the magnetization line 54A2a located on the positive upstream side included in one of the linear magnetization regions 54A2 and the magnetization line 54A2a located on the positive upstream side included in the other of the linear magnetization regions 54A2). Furthermore, in the same manner as measuring multiple dPES(n) and multiple dPES(n-3) on multiple first positions 74 and multiple second positions 76 on a pair of linear magnetized regions 54A1 included in the servo pattern pair, multiple dPES(n) and multiple dPES(n-3) are also measured on multiple first positions 74 and multiple second positions 76 on a pair of linear magnetized regions 54A1 included in the servo pattern pair. In addition, in the same manner as measuring multiple ΔdPES based on the multiple dPES(n) and multiple dPES(n-3) measured on multiple first positions 74 and multiple second positions 76 on a pair of linear magnetized regions 54A1 included in the servo pattern pair, multiple ΔdPES are also measured based on the multiple dPES(n) and multiple dPES(n-3) measured on multiple first positions 74 and multiple second positions 76 on a pair of linear magnetized regions 54A2 included in the servo pattern pair.

[0260] Furthermore, in the same manner as setting multiple first positions 74 and multiple second positions 76 on a pair of servo patterns 52A included in the servo pattern pair, multiple first positions 74 and multiple second positions 76 are also set on a pair of servo patterns 52B adjacent in the width direction WD. Furthermore, in the same manner as measuring multiple dPES(n) and multiple dPES(n-3) on multiple first positions 74 and multiple second positions 76 on a pair of servo patterns 52A included in the servo pattern pair, multiple dPES(n) and multiple dPES(n-3) are also measured on multiple first positions 74 and multiple second positions 76 on a pair of servo patterns 52B adjacent in the width direction WD. In addition, in the same manner as measuring multiple dPES(n) and multiple dPES(n-3) on a pair of servo patterns 52A included in the servo pattern pair, multiple ΔdPES are also measured based on multiple dPES(n) and multiple dPES(n-3) on a pair of servo patterns 52B adjacent in the width direction WD.

[0261] However, if the magnetic tape MT does not deform in the width direction WD and the straightness of the servo pattern 52 is ideal, but the spacing of the servo read element pairs (i.e., the spacing between one servo read element SR4 and the other servo read element SR4 in the width direction WD) is offset from the design center, dPES becomes a value equivalent to the amount by which the spacing of the servo read element pairs is offset from the design center. Furthermore, if the magnetic tape MT deforms in the width direction WD, dPES becomes a value equivalent to the amount of deformation of the magnetic tape MT in the width direction WD.

[0262] However, by measuring ΔdPES (i.e., the difference between dPES(n) and dPES(n-3)), the amount of deformation of the tape MT in the width direction WD cancels out the amount of offset of the spacing of the servo read element pairs from the design center.

[0263] In detail, dPES includes a value corresponding to the amount by which the spacing of the servo read element pair is offset from the design center, a value corresponding to the amount of deformation of the magnetic tape MT in the width direction WD, and a value representing the linearity of the servo pattern 52. However, for example, in the case where there is no deformation of the magnetic tape MT in the width direction WD and the spacing of the servo read element pair is offset from the design value, since both dPES(n) and dPES(n-3) contain the same offset of the spacing of the servo read element pair from the design value, by calculating the difference between dPES(n) and dPES(n-3), the offset of the spacing between the servo read elements SR of a pair of servo read elements SR from the design value is canceled out, and only the value representing the linearity of the servo pattern 52 is calculated. Similarly, even if the magnetic tape MT deforms in the width direction WD, since it can be considered that the magnetic tape MT deforms in the same way at the first position 74 and the second position 76, the amount of deformation of the magnetic tape MT in the width direction WD is canceled out by calculating the difference between dPES(n) and dPES(n-3), and only the value representing the linearity of the servo pattern 52 is calculated. Therefore, the linearity of the servo pattern 52 is represented by multiple ΔdPES measured based on multiple dPES(n) and multiple dPES(n-3) corresponding to multiple first positions 74 and multiple second positions 76.

[0264] Therefore, in Figure 14 In step ST12 of the linearity checking method shown, an index is obtained based on multiple ΔdPES. The following describes a specific example of the method for obtaining an index based on multiple ΔdPES and the method for checking the linearity of the servo pattern 52 of the magnetic tape MT using the index.

[0265] As an example, such as Figure 17 As shown, when the data regeneration element DR with a length β1 of 350 nm is aligned with the center of the segmented data track DT_N with a spacing Tp of 500 nm in the width direction WD, blanks BS1 and BS2 are generated between the segmented data track DT_N and the data regeneration element DR. Blank BS1 is generated on the side of the first direction WD1, and blank BS2 is generated on the side of the second direction WD2.

[0266] The lengths of the blank space BS1 and BS2 in the width direction WD are respectively equivalent to 15% of the spacing Tp.

[0267] exist Figure 14In step ST12 of the linearity checking method shown, the average value μ and standard deviation σ of the multiple ΔdPES measured from the servo pattern pair are calculated. The standard deviation σ represents the degree of linearity of the servo pattern 52. The smaller the standard deviation σ, the higher the linearity of the servo pattern 52. Therefore, in the above-described servo pattern recording process, it is preferable to record the servo pattern 52 onto the magnetic tape MT in a manner that minimizes the standard deviation σ.

[0268] exist Figure 17 Figure 78 is shown below. Figure 78 is a graph representing the normal distribution obtained from the mean μ and standard deviation σ. If the total area of ​​the closed region enclosed by Figure 78 is set to 100%, then ΔdPES exists with a probability of 68.3% in the interval of σ, with a probability of 95.4% in the interval of 2σ, and with a probability of 99.7% in the interval of 3σ.

[0269] exist Figure 14 In step ST12 of the linearity check method shown, 3σ is calculated based on the standard deviation σ. 3σ is an indicator of the degree to which multiple ΔdPES values ​​are discrete from the average value μ. The smaller the standard deviation σ, the smaller the 3σ, and the higher the linearity of the servo pattern 52. The higher the linearity of the servo pattern 52, the easier it is for the data recording element DW to record data at the position desired by the user, etc., within the magnetic tape MT, and the easier it is for the data playback element DR to align with the segmented data track DT_N.

[0270] Therefore, in order to easily record data at the desired location within the magnetic tape MT and to easily align the data playback element DR with the split data track DT_N, in Figure 14 In step ST14 of the linearity check method shown, it is determined whether the linearity criterion of "3σ is controlled below 15% of the spacing Tp" is met. This is because, as long as 3σ is controlled below 15% of the spacing Tp, it can be expected that the data regeneration element DR is aligned with the segmented data track DT_N with a probability of 99.7%.

[0271] If the linearity judgment condition is met, the linearity of the servo pattern 52 is determined to be within the allowable range; if the linearity judgment condition is not met, the linearity of the servo pattern 52 is determined to be outside the allowable range. Then, a magnetic tape MT is used if the linearity of the servo pattern 52 is determined to be within the allowable range, and a magnetic tape MT is not used if the linearity of the servo pattern 52 is determined to be outside the allowable range. Furthermore, if the linearity of the servo pattern 52 is determined to be within the allowable range, the servo pattern recording head WH is not replaced; if the linearity of the servo pattern 52 is determined to be outside the allowable range, the servo pattern recording head WH is replaced (for example, replaced with a servo pattern recording head WH whose linearity of the gap pattern G is improved).

[0272] In this embodiment, the standard deviation σ is an example of the "standard deviation" involved in the technology disclosed herein. Furthermore, in this embodiment, 3σ is an example of the "index" involved in the technology disclosed herein and "a value equivalent to three times the standard deviation of multiple PES difference gaps".

[0273] exist Figure 18 The diagram illustrates the distribution of multiple dPES obtained from a magnetic tape MT manufactured using conventional techniques without using linearity judgment conditions, and an example of the distribution of multiple dPES obtained from a magnetic tape MT manufactured via a process in which the linearity of the servo pattern 52 is determined to be within the permissible range using linearity judgment conditions. Figure 19 The diagram shows an example of the distribution of multiple ΔdPES obtained from a magnetic tape MT manufactured using conventional techniques without using linearity judgment conditions, and an example of the distribution of multiple ΔdPES obtained from a magnetic tape MT manufactured via a process in which the linearity of the servo pattern 52 is determined to be within the allowable range using linearity judgment conditions.

[0274] As an example, such as Figure 18 As shown, the distribution of multiple dPES obtained from a magnetic tape MT manufactured through a process in which the linearity of the servo pattern 52 is determined to be within the allowable range using a linearity judgment condition has better concentration than the distribution of multiple dPES obtained from a magnetic tape MT manufactured using conventional techniques without using a linearity judgment condition. That is, the dispersion of dPES is smaller.

[0275] As an example, such as Figure 19 As shown, the distribution of multiple ΔdPES obtained from a magnetic tape MT manufactured through a process in which the linearity of the servo pattern 52 is determined to be within the allowable range using a linearity judgment condition has better concentration than the distribution of multiple ΔdPES obtained from a magnetic tape MT manufactured using conventional techniques without using a linearity judgment condition. That is, the dispersion of ΔdPES is smaller.

[0276] exist Figure 20A The diagram shows an example of the distribution of multiple ΔdPES values ​​obtained under the first condition shown in Table 1. Figure 20B The figure shows an example of the distribution of multiple ΔdPES obtained under the second condition shown in Table 2.

[0277] [Table 1]

[0278] [Table 2]

[0279] As an example, such as Figure 20A and Figure 20B As shown, the distributions of multiple ΔdPES obtained under condition 1 exhibit better centrality than those obtained under condition 2. That is, the dispersion of ΔdPES is smaller.

[0280] Table 3 shows the 3σ values ​​obtained when manufacturing magnetic tape MT using the first servo pattern recording head (hereinafter, also referred to as "first head"), the second servo pattern recording head (hereinafter, also referred to as "second head"), and the third servo pattern recording head (hereinafter, also referred to as "third head") under condition 1. Table 4 shows the 3σ values ​​obtained when manufacturing magnetic tape MT using the first head, the second head, and the third head under condition 2.

[0281] Furthermore, the first magnetic head is a servo pattern recording head based on previously known technology, with the opening of the gap pattern G formed through MEMS processing. The second magnetic head is formed using the second method described above (through FIB or laser processing). Figure 13 The servo pattern recording head WH is formed by trimming the full width of the opening 66A shown to form a groove 71 and filling the groove 71 with a non-magnetic body 68. The third magnetic head is a servo pattern recording head obtained by MEMS machining the opening of the gap pattern G under different machining conditions than those used in MEMS machining of the opening of the gap pattern G of the first servo pattern recording head.

[0282] [Table 3]

[0283] [Table 4]

[0284] Next, the function of the magnetic tape system 10 according to this embodiment will be explained.

[0285] First, the case where data is simultaneously recorded on data tapes DB1 and DB2, where the linearity of all servo patterns 52 being checked is within the allowable range (i.e., the linearity judgment condition is met) is determined by the first recording module DWM1 using a linearity check method, and multiple data tracks DT are formed between servo tapes SB.

[0286] As an example, such as Figure 21 As shown, firstly, a pair of first servo read elements SRa (hereinafter, also simply referred to as "a pair of first servo read elements SRa") included in the servo read element pair are positioned on the servo tape pair. Specifically, one of the first servo read elements SRa (hereinafter, also referred to as "one first servo read element SRa") is positioned on the servo tape SB3, and the other first servo read element SRa (hereinafter, also referred to as "another first servo read element SRa") is positioned on the servo tape SB1. More specifically, the first recording module DWM1 is positioned on the magnetic tape MT by moving the magnetic head 28 along the width direction WD, so that one first servo read element SRa is positioned on the path Pa1 of the servo tape SB3, and the other first servo read element SRa is positioned on the path Pa1 of the servo tape SB1.

[0287] In this state, the magnetic tape MT is fed in the forward direction, and the data recording elements DW1 of the first recording module DWM1 perform recording processing. Thus, as an example, ... Figure 22 As shown, on the magnetic tape MT, the data recording elements DW1 of the first recording module DWM1 form the split data track DT_1.

[0288] After forming the split data track DT_1, the magnetic tape MT is moved in the reverse direction, thereby returning the first recording module DWM1 to the starting position of the split data track DT_1 formation. Then, with the magnetic head 28 offset only by the pitch Tp along the second direction WD2, the magnetic tape MT is moved in the forward direction, and the data recording elements DW1 of the first recording module DWM1 perform recording processing. Thus, the split data track DT_2 is formed on the magnetic tape MT by the data recording elements DW1 of the first recording module DWM1.

[0289] In the same manner as forming the segmented data tracks DT_1 and DT_2 sequentially, the segmented data tracks DT_3 to DT_12 are formed sequentially by the data recording elements DW1 of the first recording module DWM1. Thus, as an example, Figure 23As shown, in the width direction WD, a data band DB2 containing data tracks DT1 to DT8 is formed between servo band SB2 and servo band SB3, and in the width direction WD, a data band DB1 containing data tracks DT1 to DT8 is formed between servo band SB2 and servo band SB1.

[0290] Furthermore, when segmented data tracks DT_1 to DT_12 are formed sequentially, the first servo readout element SRa is sequentially located on paths Pa1 to Pa12, which are set at intervals Tp from the first direction WD1 side to the second direction WD2 side for the plurality of servo patterns 52 contained in the servo band SB. Then, the servo patterns 52 in each servo band SB are read by the first servo readout element SRa along paths Pa1 to Pa12, and servo control is performed according to the servo pattern signals obtained therefrom.

[0291] Next, the process of regenerating data sequentially from the segmented data track DT_1 to the segmented data track DT_12 contained in each data track DT by the regeneration module DRM will be explained.

[0292] As an example, such as Figure 24 and Figure 25 As shown, among the multiple servo patterns 52 included in the servo band SB, paths Pb1 to Pb12 are set at intervals Tp from the first direction WD1 side to the second direction WD2 side. Paths Pb1 to Pb12 correspond to paths Pa1 to Pa12, and paths Pb1 to Pb12 are respectively set at positions offset by a distance Dr from each of paths Pa1 to Pa12 towards the first direction WD1 side.

[0293] As an example, such as Figure 24 As shown, firstly, a pair of second servo read elements SRb (hereinafter also simply referred to as "a pair of second servo read elements SRb") included in the servo read element pair are positioned on the servo tape pair. Specifically, one of the second servo read elements SRb (hereinafter also referred to as "one second servo read element SRb") is positioned on the servo tape SB3, and the other second servo read element SRb (hereinafter referred to as "the other second servo read element SRb") is positioned on the servo tape SB1. More specifically, the regeneration module DRM is positioned on the magnetic tape MT by moving the magnetic head 28 along the width direction WD, so that one second servo read element SRb is positioned on the path Pb1 of the servo tape SB3, and the other second servo read element SRb is positioned on the path Pb1 of the servo tape SB1.

[0294] In this state, the magnetic tape MT is fed in the forward direction, and the data regeneration elements DR of the regeneration module DRM perform regeneration processing. Thus, on the magnetic tape MT, data is regenerated from the split data track DT_1 by the data regeneration elements DR of the regeneration module DRM.

[0295] After data regeneration from the split data track DT_1, the magnetic tape MT is moved in the reverse direction, thereby returning the regeneration module DRM to the position where data regeneration from the split data track DT_1 was performed. Then, with the magnetic head 28 offset only by the pitch Tp along the second direction WD2, the magnetic tape MT is moved in the forward direction, and the data regeneration elements DR of the regeneration module DRM perform regeneration processing. Thus, data is regenerated from the split data track DT_2 on the magnetic tape MT by the data regeneration elements DR of the regeneration module DRM.

[0296] In the same manner as the sequential regeneration of data from split data tracks DT_1 and DT_2, the data regeneration elements DR of the regeneration module DRM sequentially regenerate data from split data track DT_3 to split data track DT_12.

[0297] exist Figure 25 In the example shown, one second servo read element SRb is located on path Pb12 of servo tape SB3, and another second servo read element SRb is located on path Pb12 of servo tape SB1. In this state, the magnetic tape MT is fed in the forward direction, and the data regeneration elements DR of the regeneration module DRM perform regeneration processing. Thus, on the magnetic tape MT, data is regenerated from the split data track DT_12 by the data regeneration elements DR of the regeneration module DRM.

[0298] Here, regarding the regeneration of data from split data tracks DT_1 to DT_12, an example is given of a method in which the data is regenerated sequentially from split data track DT_1 to split data track DT_12. However, this is only one example. The data can also be regenerated sequentially from split data track DT_12 to split data track DT_1, or it can be regenerated from a split data track DT_N specified by the user or others.

[0299] In addition, Figures 22-25 The example shown illustrates a case where the segmented data tracks DT_1 to DT_12 are staggered and overlapped sequentially along the second direction WD2 with a spacing Tp, but the technique disclosed herein is not limited to this. For example, as Figure 26As shown, multiple segmented data tracks DT_N can also be formed by overlapping along the first direction WD1 in an SMR manner. In this case, the second recording module DWM2 is used. Specifically, the magnetic tape MT is moved in the reverse direction by moving the pair of third servo read elements SRc (hereinafter also simply referred to as "the pair of third servo read elements SRc") included in the servo read element pair sequentially from path Pa12 to path Pa1, thereby moving the pair of third servo read elements SRc along path P and reading the servo pattern 52 through the pair of third servo read elements SRc. According to the servo pattern signal obtained therefrom, the magnetic head 28 is moved along the first direction WD1, and the segmented data tracks DT_12 to DT_1 are overlapped sequentially along the first direction WD1.

[0300] In this case, data is also regenerated from the segmented data tracks DT_1 to DT_12 by the data regeneration elements DR of the regeneration module DRM. Paths Pb1 to Pb12 are respectively set at positions offset by a distance Dr from each of paths Pa1 to Pa12 towards the second direction WD2. When regenerating data from the segmented data tracks DT_1 to DT_12, the servo pattern 52 is read by the second servo read element SRb using paths Pb1 to Pb12, and servo control is performed according to the servo pattern signal obtained therefrom.

[0301] Here, regarding the regeneration of data from split data tracks DT_1 to DT_12, an example is given of a method in which the data is regenerated sequentially from split data track DT_1 to split data track DT_12. However, this is only one example. The data can also be regenerated sequentially from split data track DT_12 to split data track DT_1, or it can be regenerated from a split data track DT_N specified by the user or others.

[0302] As explained above, in this embodiment, a straightness inspection method (see reference) is used in the inspection process included in the manufacturing method of the magnetic tape MT. Figure 14 The linearity of the servo pattern 52 recorded on the magnetic tape MT during the servo pattern recording process is checked (see reference). Figure 14 Step ST14 is shown.

[0303] In this embodiment, in order to check the straightness of the servo pattern 52, multiple ΔdPES (reference) values ​​are measured. Figure 16 ΔdPES is the difference between dPES(n-3) and dPES(n) (see reference). Figure 16 ).

[0304] dPES(n-3) is the difference in PES between a pair of first positions 74 corresponding to each other in the width direction WD of a servo pattern pair recorded at corresponding positions in the width direction WD between one servo band SB (e.g., servo band SB3) and another servo band SB (e.g., servo band SB1) of a servo band pair (reference). Figure 16 ). dPES(n) is the difference in PES between a pair of second positions 76, offset from a pair of first positions 74 toward the width direction WD by a distance greater than the distance INT1, in a servo pattern pair recorded at corresponding positions in the width direction WD between one servo band SB (e.g., servo band SB3) and another servo band SB (e.g., servo band SB1) of a servo band pair (reference). Figure 16 ).

[0305] Multiple ΔdPES values ​​are obtained by measuring ΔdPES at intervals INT2 along the width direction WD in a pair of servo patterns 52. In this embodiment, in order to check the straightness of the servo pattern 52, the degree of dispersion of the multiple ΔdPES values ​​from the average value of the multiple ΔdPES values ​​is obtained as an indicator of the non-linearity of the servo pattern 52 (see reference). Figure 14 Step ST12 is shown. Then, the linearity of the servo pattern 52 of the magnetic tape MT is checked using an index representing the nonlinearity of the servo pattern 52 (see reference). Figure 14 Step ST14 is shown.

[0306] In this embodiment, the condition that the index representing the nonlinearity of the servo pattern 52 is controlled to be less than 15% of the pitch Tp is met (see reference). Figure 17 The linearity of the servo pattern 52 of the magnetic tape MT is determined to be within the allowable range (i.e., the linearity of the servo pattern 52 used for servo control is acceptable). However, if the condition that the index representing the non-linearity of the servo pattern 52 is controlled to be less than 15% of the pitch Tp is not met, the linearity of the servo pattern 52 of the magnetic tape MT is determined to be outside the allowable range (i.e., the linearity of the servo pattern 52 used for servo control is problematic). 15% of the pitch Tp corresponds to the length of the blank BS1 in the width direction WD and the length of the blank BS2 in the width direction WD (see reference). Figure 17 Each of these refers to the fact that the index control is below 15% of the spacing Tp, meaning that high-precision servo control can be achieved compared to the case where the index exceeds 15% of the spacing Tp. This means that multiple segmented data tracks DT_N can be formed with high precision, and the data regeneration element DR can perform high-precision tracking of the segmented data tracks DT_N.

[0307] Thus, by determining whether the condition that the index representing the nonlinearity of the servo pattern 52 is controlled to be less than 15% of the pitch Tp is met, a magnetic tape MT containing only multiple servo patterns 52 that meet the condition of the index representing the nonlinearity of the servo pattern 52 being controlled to be less than 15% of the pitch Tp can be used as a shipping magnetic tape MT. By using a magnetic tape MT that guarantees the linearity of the servo pattern 52 at such a high level as a shipping magnetic tape MT, it is possible to improve the accuracy of data recording on the magnetic tape MT and the accuracy of reproducing the data recorded on the magnetic tape MT.

[0308] In particular, in this embodiment, it is determined whether the index representing the non-linearity of the servo pattern 52 contained in the two servo tapes SB (i.e., servo tape SB1 and servo tape SB3) spanning servo tape SB2 is controlled to be less than 15% of the pitch Tp. Therefore, a magnetic tape MT whose linearity of the servo pattern 52 contained in the two servo tapes SB (i.e., servo tape SB1 and servo tape SB3) spanning servo tape SB2 is guaranteed can be used as a shipping magnetic tape MT. Thus, the shipping magnetic tape MT used in this way can help improve the accuracy of simultaneously recording data on data tapes DB1 and DB2 (in other words, the accuracy of parallel recording data on data tapes DB1 and DB2) and the accuracy of simultaneously reproducing data from data tapes DB1 and DB2 (in other words, the accuracy of parallel reproducing data from data tapes DB1 and DB2).

[0309] Furthermore, in this embodiment, the metrics obtained for the servo tape pairs (i.e., servo tapes SB1 and SB3) included in the magnetic tape MT are controlled to be less than 15% of the pitch Tp. Therefore, compared to the case where the metrics obtained from adjacent servo tapes SB in the width direction WD (e.g., servo tapes SB2 and SB3) are controlled to be less than 15% of the pitch Tp, it is possible to improve the accuracy of recording data on the magnetic tape MT and the accuracy of reproducing the data recorded on the magnetic tape MT within a wide range (in this embodiment, data tapes DB1 and DB2) in the width direction WD of the magnetic tape MT.

[0310] Furthermore, in this embodiment, multiple segmented data tracks DT_N are formed on a magnetic tape MT that satisfies the condition that the index representing the nonlinearity of the servo pattern 52 is controlled to be less than 15% of the pitch Tp by recording data in an SMR manner according to multiple servo patterns 52. Therefore, the quality of the multiple segmented data tracks DT_N formed by recording data in an SMR manner can be guaranteed at a high level, and data can be reproduced from the multiple segmented data tracks DT_N with good accuracy.

[0311] In particular, in this embodiment, multiple split data tracks DT_N are formed on the magnetic tape MT by recording data in an SMR manner according to multiple servo patterns 52, wherein the index indicating the nonlinearity of the servo pattern 52 contained in the servo tape pair (i.e., servo tapes SB1 and SB3) contained in the magnetic tape MT is controlled to be less than 15% of the pitch Tp. Therefore, compared with the case where data is recorded in an SMR manner on the magnetic tape MT, wherein the index obtained from adjacent servo tapes SB (e.g., servo tapes SB2 and SB3) in the width direction WD is controlled to be less than 15% of the pitch Tp, the quality of the multiple split data tracks DT_N formed by recording data in an SMR manner can be guaranteed at a high level within a wide range (in this embodiment, data tapes DB1 and DB2) in the width direction WD of the magnetic tape MT, and data can be reproduced from the multiple split data tracks DT_N with high precision.

[0312] Furthermore, in this embodiment, the average value μ and standard deviation σ of multiple ΔdPES are calculated. Then, as an indicator of the nonlinearity of the servo pattern 52, a graph 78 representing a normal distribution obtained from the average value μ and standard deviation σ (see reference) is used. Figure 17 3σ (reference) Figure 17 Within the 3σ closed region in Figure 78, ΔdPES exists with a probability of 99.7%. In this embodiment, by determining whether the condition of 3σ being controlled to be less than 15% of the spacing Tp is met, a magnetic tape MT containing only multiple servo patterns 52 that satisfy the condition of 3σ being controlled to be less than 15% of the spacing Tp can be used as a shipping magnetic tape MT. By using a magnetic tape MT that guarantees the linearity of the servo patterns 52 at such a high level as a shipping magnetic tape MT, it is possible to improve the accuracy of data recording on the magnetic tape MT and the accuracy of reproducing the data recorded on the magnetic tape MT.

[0313] In particular, in this embodiment, a shipping magnetic tape MT can be used that records only a plurality of servo patterns 52 that satisfy the condition that the 3σ obtained from the servo tape pairs (i.e., servo tapes SB1 and SB3) included in the magnetic tape MT is controlled to be less than 15% of the pitch Tp. Therefore, compared with a magnetic tape MT that records only a plurality of servo patterns 52 that satisfy the condition that the 3σ obtained from the servo tapes SB (e.g., servo tapes SB2 and SB3) adjacent in the width direction WD is controlled to be less than 15% of the pitch Tp, the shipping magnetic tape MT used in this way can help improve the accuracy of recording data on the magnetic tape MT and the accuracy of reproducing the data recorded on the magnetic tape MT within a wide range (in this embodiment, data tapes DB1 and DB2) in the width direction WD of the magnetic tape MT.

[0314] Furthermore, in this embodiment, as a reference for ΔdPES (reference) Figure 16 The interval INT1 for the determination of ) (reference) Figure 16 The interval closest to the reference interval was used, which is a natural multiple of the interval INT2 (in Figure 16 In the example shown, it is 3 times (and is equivalent to length L1) (see reference). Figure 11 The difference between the interval INT1 and the spacing Tp (refer to Figure 10) is half. Therefore, compared to the case where the interval INT1 is set to be independent of the length L1 and the spacing Tp, even if the multiple segmented data tracks DT_N are high-density, the data regeneration element DR can still be accurately aligned with each of the multiple segmented data tracks DT_N during data regeneration.

[0315] Furthermore, in this embodiment, as a reference for ΔdPES (reference) Figure 16 The interval INT1 for the determination of ) (reference) Figure 16 ), used an interval equivalent to INT2 (see reference) Figure 16 The interval is 3 times that of the previous one. Therefore, it is possible to collect multiple ΔdPES (reference) without over- or under-collection to obtain an index representing the nonlinearity of the servo pattern 52. Figure 16 ).

[0316] Interval INT1 (reference) Figure 16 This interval (Dr) represents the distance Dr that the head 28 moves along the width direction WD during tracking when reproducing data between adjacent segmented data tracks DT_N in the width direction WD. When the distance Dr is short, tracking during data recording and tracking during data reproduction are performed with the positions of the first servo read element SRa used during data recording and the second servo read element SRb used during data reproduction being close. Therefore, even if the servo pattern signal is distorted, the effect of the distortion can be suppressed to a small extent. Conversely, if the distance Dr becomes longer, the effect of the distortion becomes relatively large, and the positional offset caused by the distortion becomes larger.

[0317] If we assume that data is recorded on magnetic tape MT in the SMR mode, then the difference between the position of the first servo read element SRa when the split data track DT_1 is formed during the first data recording and the position of the second servo read element SRb when the split data track DT_2 is formed during the second data recording is equivalent to the pitch Tp.

[0318] Distance Dr during data regeneration (reference) Figure 11 , Figure 24 and Figure 25 ) Comparison of spacing Tp (refer to Figure 10 and Figures 23-25In the case of a short time, the effect of position offset during data regeneration will be controlled within the range of the effect of position offset during data recording, and the effect of linearity of servo pattern 52 will be reduced.

[0319] Conversely, when the distance Dr during data regeneration is greater than the spacing Tp, the effect of positional offset during data regeneration is not controlled within the range of positional offset during data recording, and the linearity of the servo pattern 52 is amplified. This leads to a decrease in servo control performance.

[0320] Therefore, in this embodiment, the interval INT1 (reference) is the interval equivalent to the distance Dr. Figure 16 The interval is greater than the spacing Tp. Therefore, the servo pattern 52 is formed in such a way that an index (e.g., 3σ) representing the degree of dispersion of the multiple ΔdPES determined according to the interval INT1 greater than the spacing Tp is controlled to be less than 15% of the spacing Tp. Thus, compared to the case where the interval INT1 is less than the spacing Tp, even with a high density of multiple segmented data tracks DT_N, the data reproduction element DR can still be accurately aligned with each of the multiple segmented data tracks DT_N during data reproduction.

[0321] Furthermore, in the above embodiments, the metrics (e.g., 3σ) obtained for each servo band pair (e.g., each of servo bands SB1 and SB3) are controlled to be less than 15% of the pitch Tp, but the disclosed technology is not limited to this. For example, the metrics obtained for each servo band pair (e.g., each of servo bands SB1 and SB3) can be controlled to be less than 10% of the pitch Tp, or the metrics obtained for each servo band pair (e.g., each of servo bands SB1 and SB3) can be controlled to be less than 5% of the pitch Tp. Figure 17 In the example shown, a length β1 of 500 nm is cited. However, if the specification is controlled to less than 10% of the pitch Tp, the length β1 can be extended to 400 nm, and if the specification is controlled to less than 5% of the pitch Tp, the length β1 can be extended to 450 nm. Thus, if the length β1 can be extended, the performance of data playback can be expected to be improved. Furthermore, PES caused by the variation of the magnetic tape MT in the width direction WD is also the main cause of positional offset of the data playback element DR. However, by controlling the specification to less than 10% or less than 5% of the pitch Tp, it is possible to improve the design tolerance for positional offset caused primarily by PES.

[0322] In the above embodiment, the case where the segmented data tracks DT_1 to DT_12 are staggered and overlapped sequentially along the second direction WD2 with a spacing Tp has been described, but the technology disclosed herein is not limited to this. For example, as Figure 26As shown, multiple segmented data tracks DT_N can also be formed by overlapping along the first direction WD1 in an SMR manner. In this case, the second recording module DWM2 is used. Specifically, a pair of third servo read elements SRc are moved sequentially from path P12 to path P1 to cause the magnetic tape MT to travel in the reverse direction, thereby moving the pair of third servo read elements SRc along path P, and reading the servo pattern 52 by the pair of third servo read elements SRc. According to the servo pattern signal obtained therefrom, the magnetic head 28 is moved along the first direction WD1, and the segmented data tracks DT_12 to DT_1 are overlapped sequentially along the first direction WD1. The regeneration of data from the segmented data tracks DT_1 to DT_12 is performed by the data regeneration elements DR of the regeneration module DRM.

[0323] In addition, Figure 24 and Figure 25 In the example shown, the path Pb1~Pb12 used in reading the servo pattern 52 during data regeneration is set at a position offset by a distance Dr from the path Pa1~Pa12 towards the first direction WD1. Figure 26 In the example shown, the path Pb1~Pb12 used in reading the servo pattern 52 during data regeneration is set at a position offset by a distance Dr from the second direction WD2 compared to the path Pa1~Pa12.

[0324] In recent years, research has been advancing on technologies related to reducing the impact of TDS. It is known that TDS is affected by factors such as temperature, humidity, the pressure of the magnetic tape wound on the disc, and deterioration over time. Without any measures, TDS increases, causing derailment (i.e., the positional shift of the data recording and playback element DRW relative to the split data track DT_N within the data tape DB) in scenarios where magnetic processing of the data tape DB is performed.

[0325] For example, if the width of the magnetic tape MT shrinks over time, derailment may occur. Derailment refers to the state in which the data recording playback element DRW is not located on the designated split data track DT_N among the split data tracks DT1_1, DT1_2, DT1_3, DT1_4, ..., DT1_11 and DT1_12 contained in the split data track group (i.e., in the width direction WD, the position of the designated split data track DT_N is offset from the position of the data recording playback element DRW).

[0326] The width of the magnetic tape MT may sometimes increase, which can also lead to derailment. Specifically, if the width of the magnetic tape MT narrows or widens over time, the position of the servo read element SR relative to the servo pattern 52 will shift from its predetermined position (i.e., the predetermined position for each of the linear magnetization regions 54A1, 54A2, 54B1, and 54B2) along the width direction WD. If the position of the servo read element SR relative to the servo pattern 52 shifts from its predetermined position along the width direction WD, the accuracy of the servo control decreases, and the tracks within the data tape DB (e.g., the specified segmented data track DT_N among the segmented data tracks DT1_1, DT1_2, DT1_3, DT1_4, ..., DT1_11 and DT1_12) shifts from the position of the data recording and playback element DRW. Consequently, the initially predetermined segmented data track DT_N cannot be magnetically processed.

[0327] As a method to reduce the impact of TDS, adjusting the width of the magnetic tape MT by adjusting the tension applied to the MT can be considered. However, if the deformation of the magnetic tape MT in the width direction WD is too large, derailment may not be eliminated even if the tension applied to the MT is adjusted. Furthermore, increasing the tension applied to the MT will increase the load on the MT, which may shorten its lifespan. Moreover, if the tension applied to the MT is too weak, the contact state between the magnetic head 28 and the magnetic tape MT becomes unstable, making magnetic processing of the MT by the magnetic head 28 difficult. As an example of a method to reduce the impact of TDS other than adjusting the tension applied to the MT, such as... Figure 27 As shown, there is a known method for maintaining the position of the servo read element SR relative to the servo pattern 52 at a predetermined position determined by design by causing the magnetic head 28 to skew on the magnetic tape MT.

[0328] Therefore, as an example, such as Figure 27 As shown, the first recording module DWM1 can be configured to be tilted relative to the width direction WD along the surface 31 of the magnetic tape MT with the rotation axis RA1 as the center. Furthermore, the playback module DRM can be configured to be tilted relative to the width direction WD along the surface 31 of the magnetic tape MT with the rotation axis RA2 as the center. Additionally, the second recording module DWM2 can be configured to be tilted relative to the width direction WD along the surface 31 of the magnetic tape MT with the rotation axis RA3 as the center.

[0329] exist Figure 27 In the example shown, the length L2 of each data recording element DW contained in the recording module DWM in the width direction WD is compared with the aforementioned length L1 (see reference). Figure 11 The same. And, in Figure 27In the example shown, the lengths of the data regeneration elements DR contained in the regeneration module DRM in the width direction WD are lengths β2 and β1 (see reference). Figure 1 The positions of the first servo read element SRa, the second servo read element SRb, and the third servo read element SRc in the width direction WD are aligned.

[0330] The orientation of the first recording module DWM1, the playback module DRM, and the second recording module DWM2 relative to the width direction WD can be fixed or changed depending on the situation (e.g., the degree of deformation of the magnetic tape MT). When changing the orientation of the first recording module DWM1, the playback module DRM, and the second recording module DWM2 relative to the width direction WD, a tilting mechanism (not shown) operating under the control of the processing device 30 is used. The tilting mechanism is mechanically connected to the first recording module DWM1, the playback module DRM, and the second recording module DWM2. In this case, depending on the situation, the tilting degree of the first recording module DWM1, the playback module DRM, and the second recording module DWM2 relative to the width direction WD is adjusted by the tilting mechanism under the control of the processing device 30.

[0331] For example, the tilt of the first recording module DWM1, the regeneration module DRM, and the second recording module DWM2 relative to the width direction WD is adjusted as follows: the first recording module DWM1 is rotated along the surface 31 with the rotation axis RA1 as the central axis, the regeneration module DRM is rotated along the surface 31 with the rotation axis RA2 as the central axis, and the second recording module DWM2 is rotated along the surface 31 with the rotation axis RA3 as the central axis.

[0332] In addition, an example is given here in which the first recording module DWM1, the regeneration module DRM and the second recording module DWM2 are individually controlled by a tilting mechanism to rotate. However, this is only one example. It is also possible for a single tilting mechanism to rotate the entire magnetic head 28 around the rotation axis RA2.

[0333] By tilting the recording module DWM and the playback module DRM along the surface 31 of the magnetic tape MT relative to the width direction WD, a certain offset is generated in the width direction WD between the positions of the first servo read element SRa, the second servo read element SRb, and the third servo read element SRc. In this case, the position (in other words, the path P) of the servo pattern 52 is read by each of the first servo read element SRa, the second servo read element SRb, and the third servo read element SRc, and adjusted according to the adjustment amount determined by the certain offset generated in the width direction WD.

[0334] Thus, by configuring the recording module DWM and the playback module DRM in an angled manner along the surface 31 of the magnetic tape MT relative to the width direction WD, it is possible to suppress the decrease in tracking accuracy of the magnetic head 28 on the magnetic tape MT due to deformation of the magnetic tape MT. For example, it is possible to suppress the occurrence of situations where data is not recorded at a predetermined position or cannot be reproduced from a predetermined position due to deformation of the magnetic tape MT.

[0335] In the above embodiments, a magnetic tape system 10 in which the tape cartridge 12 can be freely inserted and removed from the tape drive 14 is illustrated, but the technology disclosed herein is not limited thereto. For example, the technology disclosed herein still applies even to magnetic tape systems in which at least one tape cartridge 12 has been pre-loaded into the tape drive 14 (i.e., a magnetic tape system in which at least one tape cartridge 12 and the tape drive 14, or a tape MT and the tape drive 14 are pre-integrated (e.g., before recording data on the data tape DB)). A magnetic tape system in which at least one tape cartridge 12 is loaded into the tape drive 14 is an example of a "magnetic tape system" to which the technology disclosed herein pertains.

[0336] In the above embodiment, a single magnetic head 28 is illustrated, but the technology disclosed herein is not limited thereto. For example, multiple magnetic heads 28 may also be configured on the magnetic tape MT.

[0337] like Figure 27As shown, when the recording module DWM and the playback module DRM are tilted along the surface 31 of the magnetic tape MT relative to the width direction WD, the angles formed by the linear magnetized region 54A1 and the servo read element SR are different from those formed by the linear magnetized region 54A2 and the servo read element SR. If the angles are different, discrepancies (e.g., signal level discrepancies and waveform distortions) caused by azimuth angle loss occur between the servo pattern signal originating from the linear magnetized region 54A1 (i.e., the servo pattern signal obtained by reading the linear magnetized region 54A1 by the servo read element SR) and the servo pattern signal originating from the linear magnetized region 54A2 (i.e., the servo pattern signal obtained by reading the linear magnetized region 54A2 by the servo read element SR).

[0338] like Figure 27 As shown, when the recording module DWM and the playback module DRM are tilted along the surface 31 of the magnetic tape MT relative to the width direction WD, the servo read element SR and the linear magnetized region 54A1 (reference) Figure 6 The angle between the servo read element SR and the linear magnetized region 54A2 is greater than the angle between them. Therefore, the output servo pattern signal is smaller, and the waveform is wider. Consequently, when the magnetic tape MT is moving, the servo pattern signal read by the servo read element SR across the servo tape SB will exhibit discrepancies. Furthermore, when the servo read element SR reads the servo pattern 52B, discrepancies due to azimuth loss will also occur between the servo pattern signals originating from the linear magnetized region 54B1 and the servo pattern signals originating from the linear magnetized region 54B2. This discrepancy in the servo pattern signal may contribute to a decrease in the accuracy of servo control.

[0339] Furthermore, for example, as another known example of the servo pattern 52A, consider a configuration where the linear magnetized region 54A1 is parallel to the virtual straight line C1 and the linear magnetized region 54A2 is tilted relative to the virtual straight line C1 (i.e., only the linear magnetized region 54A2 is tilted). With this known configuration, when the servo pattern 52A is read by the servo read element SR, the angles formed by the linear magnetized region 54A1 and the servo read element SR are different from those formed by the linear magnetized region 54A2 and the servo read element SR. Thus, if the angles are different, a discrepancy due to azimuth loss occurs between the servo pattern signal originating from the linear magnetized region 54A1 and the servo pattern signal originating from the linear magnetized region 54A2. This discrepancy in the servo pattern signal can be a cause of decreased servo control accuracy.

[0340] Therefore, when the recording module DWM and the playback module DRM are tilted along the surface 31 of the magnetic tape MT relative to the width direction WD (see reference) Figure 27 As an example, such as Figure 28 As shown, magnetic tape MT1 is used instead of magnetic tape MT. The difference between magnetic tape MT1 and magnetic tape MT is that magnetic tape MT1 has frame 80 instead of frame 50. Frame 80 is defined by a set of servo patterns 82. Multiple servo patterns 82 are recorded on the servo tape SB along the length direction LD of magnetic tape MT1. The multiple servo patterns 82, like the multiple servo patterns 52 recorded on magnetic tape MT, are arranged at predetermined intervals along the length direction LD of magnetic tape MT.

[0341] exist Figure 28 In the example shown, servo patterns 82A and 82B are shown as one example of a set of servo patterns 82 included in frame 80. Servo patterns 82A and 82B are adjacent to each other along the length direction LD of the magnetic tape MT1, and within frame 80, servo pattern 82A is located on the positive upstream side and servo pattern 82B is located on the positive downstream side.

[0342] The servo pattern 82 is composed of linear magnetized region pairs 84. The linear magnetized region pairs 84 are divided into linear magnetized region pairs 84A and linear magnetized region pairs 84B. Here, the linear magnetized region pairs 84 are an example of the "linear magnetized region pairs" involved in the technology disclosed herein.

[0343] Servo pattern 82A is composed of linear magnetized regions paired with 84A. In Figure 28 In the example shown, linear magnetization regions 84A1 and 84A2 are shown as examples of linear magnetization regions 84A. Linear magnetization regions 84A1 and 84A2 are regions that are linearly magnetized.

[0344] The linear magnetization regions 84A1 and 84A2 are tilted in opposite directions relative to the virtual straight line C1. In other words, the linear magnetization region 84A1 is tilted in one direction relative to the virtual straight line C1 (e.g., from...). Figure 28 The paper is tilted (clockwise when viewed from the front side). On the other hand, the linear magnetized region 84A2 is tilted in another direction relative to the virtual straight line C1 (e.g., from...). Figure 28 The paper is tilted (counterclockwise when viewed from the front side). Linear magnetized regions 84A1 and 84A2 are not parallel to each other and are tilted at different angles relative to the virtual line C1. The tilt angle of linear magnetized region 84A1 relative to the virtual line C1 is steeper than that of linear magnetized region 84A2. Here, "steep" means, for example, that the angle of linear magnetized region 84A1 relative to the virtual line C1 is smaller than the angle of linear magnetized region 84A2 relative to the virtual line C1. Furthermore, the total length of linear magnetized region 84A1 is shorter than the total length of linear magnetized region 84A2.

[0345] Here, the linear magnetization region 84A1 is an example of the "first linear magnetization region" involved in the technology disclosed herein, the linear magnetization region 84A2 is an example of the "second linear magnetization region" involved in the technology disclosed herein, and the virtual straight line C1 is an example of the "virtual straight line" involved in the technology disclosed herein.

[0346] In the servo pattern 82A, the linear magnetization region 84A1 contains multiple magnetization lines 84A1a, and the linear magnetization region 84A2 contains multiple magnetization lines 84A2a. The number of magnetization lines 84A1a contained in the linear magnetization region 84A1 is the same as the number of magnetization lines 84A2a contained in the linear magnetization region 84A2.

[0347] Linear magnetization region 84A1 is a set of five magnetized straight lines, i.e., magnetization lines 84A1a, and linear magnetization region 84A2 is a set of five magnetized straight lines, i.e., magnetization lines 84A2a. Within the servo band SB, in the width direction WD, the positions of the two ends of linear magnetization region 84A1 (i.e., the positions of the two ends of each of the five magnetized lines 84A1a) are aligned with the positions of the two ends of linear magnetization region 84A2 (i.e., the positions of the two ends of each of the five magnetized lines 84A2a). Furthermore, an example of alignment between the positions of the two ends of each of the five magnetized lines 84A1a and the two ends of each of the five magnetized lines 84A2a is given here, but this is only one example; alignment is sufficient as long as the positions of the two ends of one or more of the five magnetized lines 84A1a are aligned with the positions of the two ends of one or more of the five magnetized lines 84A2a. Furthermore, in this specification, the concept of "alignment" includes not only the meaning of perfect alignment, but also the meaning of "alignment" that includes errors that are generally permissible in the technical field to which this disclosure pertains and do not depart from the technical spirit of this disclosure.

[0348] The servo pattern 82B is composed of linear magnetized regions paired with 84B. Figure 28 In the example shown, linear magnetization regions 84B1 and 84B2 are shown as examples of linear magnetization regions 84B. Linear magnetization regions 84B1 and 84B2 are regions that are linearly magnetized.

[0349] The linear magnetization regions 84B1 and 84B2 are tilted in opposite directions relative to the virtual straight line C2. In other words, the linear magnetization region 84B1 is tilted in one direction relative to the virtual straight line C2 (e.g., from...). Figure 28 The paper is tilted (clockwise when viewed from the front side). On the other hand, the linear magnetized region 84B2 is tilted in another direction relative to the virtual straight line C2 (e.g., from...). Figure 28The paper is tilted (counterclockwise when viewed from the front side). Linear magnetized regions 84B1 and 84B2 are not parallel to each other and are tilted at different angles relative to the virtual line C2. The tilt angle of linear magnetized region 84B1 relative to the virtual line C2 is steeper than that of linear magnetized region 84B2. Here, "steep" means, for example, that the angle of linear magnetized region 84B1 relative to the virtual line C2 is smaller than the angle of linear magnetized region 84B2 relative to the virtual line C2. Furthermore, the total length of linear magnetized region 84B1 is shorter than the total length of linear magnetized region 84B2.

[0350] Here, the linear magnetization region 84B1 is an example of the "first linear magnetization region" involved in the technology disclosed herein, the linear magnetization region 84B2 is an example of the "second linear magnetization region" involved in the technology disclosed herein, and the virtual straight line C2 is an example of the "virtual straight line" involved in the technology disclosed herein.

[0351] In the servo pattern 82B, the linear magnetization region 84B1 contains multiple magnetization lines 84B1a, and the linear magnetization region 84B2 contains multiple magnetization lines 84B2a. The number of magnetization lines 84B1a contained in the linear magnetization region 84B1 is the same as the number of magnetization lines 84B2a contained in the linear magnetization region 84B2.

[0352] The total number of magnetized lines 84B1a and 84B2a included in servo pattern 82B is different from the total number of magnetized lines 84A1a and 84A2a included in servo pattern 82A. Figure 28 In the example shown, the servo pattern 82A contains a total of 10 magnetized lines 84A1a and 84A2a, while the servo pattern 82B contains a total of 8 magnetized lines 84B1a and 84B2a.

[0353] Linear magnetization region 84B1 is a set of four magnetized straight lines, namely magnetization lines 84B1a, and linear magnetization region 84B2 is a set of four magnetized straight lines, namely magnetization lines 84B2a. Within the servo band SB, in the width direction WD, the positions of the two ends of linear magnetization region 84B1 (i.e., the positions of the two ends of each of the four magnetization lines 84B1a) are aligned with the positions of the two ends of linear magnetization region 84B2 (i.e., the positions of the two ends of each of the four magnetization lines 84B2a).

[0354] Furthermore, an example is given here where the positions of the two ends of each of the four magnetization lines 84B1a are aligned with the positions of the two ends of each of the four magnetization lines 84B2a, but this is only one example. For instance, the technique disclosed herein is valid as long as the positions of the two ends of one or more of the four magnetization lines 84B1a are aligned with the positions of the two ends of one or more of the four magnetization lines 84B2a.

[0355] Furthermore, as an example of linear magnetized region 84A1, a set of 5 magnetized straight lines, namely magnetized lines 84A1a, is listed; and as an example of linear magnetized region 84A2, a set of 5 magnetized straight lines, namely magnetized lines 84A2a, is listed; however, the technology disclosed herein is not limited to this. Similarly, as an example of linear magnetized region 84B1, a set of 4 magnetized straight lines, namely magnetized lines 84B1a, is listed; and as an example of linear magnetized region 84B2, a set of 4 magnetized straight lines, namely magnetized lines 84B2a, is listed; however, the technology disclosed herein is not limited to this. For example, the technology disclosed is valid as long as linear magnetized region 84A1 consists of magnetized lines 84A1a that help determine the number of positions of the magnetic head 28 on magnetic tape MT1, and linear magnetized region 84A2 consists of magnetized lines 84A2a that help determine the position of the magnetic head 28 on magnetic tape MT1. Furthermore, the disclosed technique is valid as long as the linear magnetization region 84B1 is a magnetization line 84B1a that helps determine the number of magnetic heads 28 on the magnetic tape MT1 and the linear magnetization region 84B2 is a magnetization line 84B2a that helps determine the number of magnetic heads 28 on the magnetic tape MT1.

[0356] Here, for reference Figure 29 The geometric characteristics of the 84A on the MT1 magnetic tape are explained for the linear magnetization region. Here, geometric characteristics refer to the commonly understood geometric properties such as length, shape, orientation, and / or position.

[0357] As an example, such as Figure 29 As shown, the geometric characteristics of the linear magnetization region pair 84A on the magnetic tape MT1 can be represented using a virtual linear region pair 86. The virtual linear region pair 86 consists of virtual linear regions 86A and 86B. The geometric characteristics of the linear magnetization region pair 84A on the magnetic tape MT1 are equivalent to the geometric characteristics of the virtual linear region pair 86 when the entire virtual linear region pair 86 is tilted relative to the virtual line C1 by tilting the axis of symmetry SA1 of the virtual linear regions 86A and 86B, which are symmetrically tilted relative to the virtual line C1, relative to the virtual line C1.

[0358] The virtual linear region is related to 86. Figure 6The linear magnetization region shown is a virtual linear magnetization region pair with the same geometric characteristics as the 54A. The virtual linear region pair 86 is a virtual magnetization region used for the purpose of illustrating the geometric characteristics of the linear magnetization region pair 86A on the magnetic tape MT1, and is not an actual existing magnetization region.

[0359] Virtual linear region 86A has the same Figure 6 The linear magnetization region 54A1 shown has the same geometric characteristics, and is composed of the same... Figure 6 The five magnetization lines 54A1a shown correspond to five virtual lines 86A1. The virtual linear region 86B has the same characteristics as... Figure 6 The linear magnetization region 54B1 shown has the same geometric characteristics, and is composed of the same... Figure 6 The five magnetization lines 54A2a shown are composed of five virtual lines 86B1.

[0360] A center O1 is provided on the virtual linear region 86. For example, the center O1 is the center of the line segment 88 that connects the center of the line 86A1 located on the upstream side of the five lines 86A1 in the positive direction with the center of the line 86B1 located on the downstream side of the five lines 86B1 in the positive direction.

[0361] The virtual linear region has the same characteristics as 86. Figure 6 The linear magnetization regions shown have the same geometric characteristics as 54A; therefore, the virtual linear regions 86A and 86B are inclined in a line-symmetrical manner with respect to the virtual straight line C1. Here, consider the assumption that... Figure 27 The servo reading element SR shown reads the virtual linear region pair 86 when the axis of symmetry SA1 of the virtual linear regions 86A and 86B is tilted relative to the virtual line C1 by an angle α (e.g., 10 degrees) about the center O1, causing the entire virtual linear region pair 86 to be tilted relative to the virtual line C1. In this case, in the width direction WD of the virtual linear region pair 86, there will be positions where virtual linear region 86A is read but virtual linear region 86B is not read, or where virtual linear region 86A is not read but virtual linear region 86B is read. That is, in each of the virtual linear regions 86A and 86B, when read by the servo reading element SR, there will be insufficient portions and unwanted portions.

[0362] Therefore, in each of the virtual linear regions 86A and 86B, the insufficient parts are supplemented and the unnecessary parts are removed. As a result, in the width direction WD, the positions of the two ends of the virtual linear region 86A (i.e., the positions of the two ends of each of the five straight lines 86A1) are aligned with the positions of the two ends of the virtual linear region 86B (i.e., the positions of the two ends of each of the five straight lines 86B1).

[0363] The resulting virtual linear region pair 86 has geometric characteristics (i.e., the geometric characteristics of the virtual servo pattern) equivalent to the geometric characteristics of the actual servo pattern 82A. Specifically, a pair of linear magnetized regions 84A with geometric characteristics equivalent to those of the virtual linear region pair 86 is recorded on the servo tape SB. This virtual linear region pair 86 is obtained by aligning the positions of the two ends of the virtual linear region 86A with the positions of the two ends of the virtual linear region 86B in the width direction WD.

[0364] Furthermore, the linear magnetization region pair 84B differs from the linear magnetization region pair 84A only in that it has four magnetization lines 84B1a instead of five magnetization lines 84A1a, and four magnetization lines 84B2a instead of five magnetization lines 84A2a. Therefore, a linear magnetization region pair 84B with geometric characteristics equivalent to the virtual linear region pair (not shown) is recorded on the servo tape SB. This virtual linear region pair is obtained by aligning the positions of the two ends of each of the four lines 86A1 with the positions of the two ends of each of the four lines 86B1 in the width direction WD.

[0365] Thus, when the recording module DWM and the playback module DRM are tilted along the surface 31 of the magnetic tape MT relative to the width direction WD (see reference). Figure 27 The magnetic tape MT1 is used, which has a servo pattern 82A formed by linear magnetization region pairs 84A and a servo pattern 82B formed by linear magnetization region pairs 84B. Therefore, even when the magnetic head 28, which is skewed on the magnetic tape MT1 in order to reduce the influence of TDS, records data on the magnetic tape MT1 or reproduces data from the magnetic tape MT1, it is still possible to improve the accuracy of recording data on the magnetic tape MT1 and the accuracy of reproducing data recorded on the magnetic tape MT1.

[0366] Additionally, a method for checking the linearity of the magnetic tape MT1 in the same manner as described above (see reference) Figure 14 This ensures the linearity of the servo pattern 82. Therefore, the same effect as the above-described implementation can be achieved.

[0367] Furthermore, in the formation of multiple servo strips SB, each comprising multiple servo patterns 82 along the length direction LD, a skew-corresponding servo pattern recording head (not shown) is used instead of the servo pattern recording head WH, in the same manner as in the above embodiment. A skew-corresponding servo pattern recording head, for example, refers to a multiple gap pattern having geometric characteristics equivalent to those of the straight line 86A1 located on the positive upstream side within the virtual linear region 86A and the straight line 86B1 located on the positive upstream side within the virtual linear region 86B, along the direction WD3 (see reference). Figure 13 A servo pattern recording head formed at equal intervals.

[0368] Furthermore, the magnetic tape MT and the magnetic head 28 are illustrated in the above embodiments, but this is only one example. For example, such as... Figure 30 As shown, magnetic tape MT2 and magnetic head 28A can also be used instead of magnetic tape MT and magnetic head 28. The difference between magnetic tape MT2 and magnetic tape MT is that it has a data tape DB0 and a servo tape SB0. Data tape DB0 is adjacent to servo tape SB1 in the width direction WD via servo tape SB1. Servo tape SB0 is adjacent to servo tape SB1 in the width direction WD via data tape DB0. The structure of servo tape SB0 is the same as that of servo tape SB described in the above embodiment, and the structure of data tape DB0 is the same as that of data tape DB described in the above embodiment.

[0369] The difference between magnetic head 28A and magnetic head 28 is that magnetic element unit 42A replaces magnetic element unit 42. The difference between magnetic element unit 42A and magnetic element unit 42 is that it has four servo read elements SR as multiple magnetic elements, and it has more data recording and playback elements DRW compared to magnetic element unit 42. The four servo read elements SR are servo read elements SR1, SR2, SR3, and SR5.

[0370] The structure of the servo read element SR5 is the same as that of the servo read element SR described in the above embodiment. The servo read element SR5 serves the servo tape SB0. In the width direction WD, a plurality of data recording and playback elements DRW are disposed between the servo read elements SR3 and SR4. The plurality of data recording and playback elements DRW disposed between the servo read elements SR3 and SR4 serve the data tape DB0.

[0371] In addition, in use Figure 30 In the examples shown, when there is no need to distinguish between data bands DB0, DB1, and DB2, they are referred to as "data band DB". Furthermore, when using... Figure 30 In the example illustration, when there is no need to distinguish between servo bands SB0, SB1, SB2, and SB3, they are referred to as "servo band SB". Furthermore, when using... Figure 30 In the example shown, when there is no need to distinguish between servo read elements SR1, SR2, SR3, and SR5, they are referred to as "servo read elements SR".

[0372] When using this magnetic tape MT2 and magnetic head 28A, for example, for each of all pairs of servo tapes SB that span more than one servo tape SB in the width direction WD, the parameters described in the above embodiment can be obtained. Here, in Figure 30In the example shown, each of all pairs of servo bands SB that span more than one servo band SB in the width direction WD refers to the combination of servo bands SB1 and SB3, the combination of servo bands SB0 and SB2, and the combination of servo bands SB0 and SB3.

[0373] Thus, by targeting each of the available parameters for all pairs of servo tapes SB that span more than one servo tape SB in the width direction WD, the same effect as described above can be achieved even when using head 28A on magnetic tape MT2.

[0374] In addition, examples of how to obtain metrics from each of the combinations of servo bands SB1 and SB3, servo bands SB0 and SB2, and servo bands SB0 and SB3 are given here. However, this is only one example. Metrics can also be obtained from one or two of the combinations of servo bands SB1 and SB3, servo bands SB0 and SB2, and servo bands SB0 and SB3.

[0375] Furthermore, in Figure 30 In the example shown, when magnetic processing is performed only on data bands DB0, DB1, and DB2 by the read / write head 28A on data bands DB0, DB1, and DB2, the metrics described in the above embodiment can be obtained for each of the data bands DB that are not used in the magnetic processing, i.e., the pair of servo bands SB (servo bands SB1 and SB2, as an example) that are not used in the magnetic processing (servo bands SB0 and SB3, as an example). In this case, the same effect as in the above embodiment can still be obtained.

[0376] in addition, Figure 30 The structure of the MT2 tape shown is only one example. Even if the number of servo tapes (SB) and data tapes (DB) is greater than that of the MT2 tape, the disclosed technology still applies. In this case, the index can be obtained for at least one of all pairs of servo tapes (DB) that span more than one servo tape DB in the width direction (WD) (i.e., at least one servo tape pair), or for at least one of all pairs of servo tapes (DB) that span more than one servo tape in the width direction (WD), excluding the pair of servo tapes (DB) not used in data recording and / or playback (i.e., at least one servo tape pair).

[0377] The descriptions and illustrations above are detailed explanations of the parts involved in the technology disclosed herein, and are merely one example of the technology disclosed herein. For example, the descriptions of the structure, function, role, and effect described above are examples of the structure, function, role, and effect of the parts involved in the technology disclosed herein. Therefore, it is natural to delete unnecessary parts, add new elements, or replace the descriptions and illustrations above without departing from the spirit of the technology disclosed herein. Furthermore, to avoid complexity and facilitate understanding of the parts involved in the technology disclosed herein, explanations of common technical knowledge and other related information that do not require special explanation based on the ability to implement the technology disclosed herein have been omitted from the descriptions and illustrations above.

[0378] In this specification, "A and / or B" has the same meaning as "at least one of A and B". That is, "A and / or B" means that it can be only A, only B, or a combination of A and B. Furthermore, in this specification, when more than three cases are connected by "and / or", the same meaning as "A and / or B" can be applied.

[0379] All documents, patent applications and technical standards described in this specification may be referenced in this specification to the same extent as the specific and individually described instances of reference to each document, patent application and technical standard.

Claims

1. A magnetic tape comprising multiple servo tapes, each recording multiple servo patterns along its length, arranged along its width. The index indicating the nonlinearity of the servo pattern is controlled to be below 15% of the track pitch. The track spacing is the distance between multiple tracks formed by recording data onto the magnetic tape by a recording element according to signals obtained from the plurality of servo patterns. The index represents the degree to which multiple PES difference gaps are discrete from the average value of the multiple PES difference gaps. The PES difference gap is the difference between the first PES difference and the second PES difference. The first PES difference is the difference in PES values ​​between a pair of corresponding first positions in the width direction of a pair of servo patterns recorded at corresponding positions in the width direction between a pair of servo bands that span more than one servo band in the width direction among the plurality of servo bands. The second PES difference is the difference in PES values ​​between a pair of second positions in the pair of servo patterns that are offset from the pair of first positions by a first predetermined interval in the width direction. The plurality of PES difference gaps are obtained by measuring the PES difference gaps at a second predetermined interval along the width direction in the pair of servo patterns. The first predetermined interval is greater than the second predetermined interval.

2. The magnetic tape according to claim 1, wherein, The plurality of tracks are formed by recording the data onto the magnetic tape using the recording element in an SMR manner.

3. The magnetic tape according to claim 1, wherein, The index is a value equivalent to three times the standard deviation of the plurality of PES difference gaps.

4. The magnetic tape according to claim 1, wherein, The first predetermined interval is the interval closest to the reference interval, which is a natural multiple of the second predetermined interval and is equivalent to half the difference between the length of the recording element (which is the length of the recording element in the width direction) and the track spacing.

5. The magnetic tape according to claim 1, wherein, The first predetermined interval is an interval that is a natural number multiple of 2 or more of the second predetermined interval.

6. The magnetic tape according to claim 1, wherein, The first predetermined interval is greater than the track spacing.

7. The magnetic tape according to claim 1, wherein, The specified index is controlled to be below 10% of the track spacing.

8. The magnetic tape according to claim 1, wherein, The specified index is controlled to be below 5% of the track spacing.

9. The magnetic tape according to claim 1, wherein, On the magnetic tape, four or more servo tapes are arranged along the width direction as the plurality of servo tapes. The index is obtained for each of the pairs of servo bands that span more than one servo band in the width direction.

10. The magnetic tape according to claim 9, wherein, The index is obtained for each of the pairs of servo bands that span more than one servo band in the width direction, except for the pair of servo bands that are not used in the recording and / or reproduction of the data.

11. The magnetic tape according to claim 9, wherein, The parameters obtained for each of the pair of servo bands are controlled to be below 15% of the track pitch.

12. The magnetic tape according to claim 9, wherein, The parameters obtained for each of the pair of servo bands are controlled to be below 10% of the track spacing.

13. The magnetic tape according to claim 9, wherein, The metric obtained for each of the pair of servo bands is controlled to be below 5% of the track pitch.

14. The magnetic tape according to claim 1, wherein, The servo pattern consists of at least one pair of linear magnetization regions. The linear magnetization region is a first linear magnetization region and a second linear magnetization region. The first linear magnetization region and the second linear magnetization region are inclined in opposite directions relative to the virtual straight line along the width direction. Compared to the second linear magnetization region, the first linear magnetization region has a steeper tilt angle relative to the virtual straight line.

15. The magnetic tape according to claim 1, wherein, The magnetic tape has a base film. The base film is composed of polyethylene terephthalate, polyethylene naphthalate, or polyamide.

16. A magnetic tape cassette, comprising: The magnetic tape according to any one of claims 1 to 15; and The outer casing contains the magnetic tape.

17. A magnetic tape system comprising: The magnetic tape according to any one of claims 1 to 15; and The magnetic head performs data recording on the magnetic tape and / or reproducing data recorded on the magnetic tape.

18. An inspection method comprising: The index is obtained from the magnetic tape according to any one of claims 1 to 15; and The magnetic tape is inspected using the aforementioned metrics.

19. The inspection method according to claim 18, wherein, Inspecting the tape includes checking the linearity of the servo pattern using the aforementioned metrics.

20. A method for manufacturing a magnetic tape, wherein the magnetic tape is a magnetic tape in which multiple servo tapes, each having a plurality of servo patterns recorded along a first length direction, are arranged along the width direction. The method for manufacturing the magnetic tape includes: A servo write head having a facing surface (i.e., an opposing surface) that faces the recording surface of the magnetic tape when recording the plurality of servo patterns along the first length direction, and a plurality of gap patterns, is positioned with the recording surface facing the plurality of gap patterns. The plurality of gap patterns are formed by spacing along the second length direction of the opposing surface and correspond to the plurality of servo patterns respectively. Using the servo write head positioned in the aforementioned posture, the plurality of servo patterns are recorded on the recording surface along the first length direction, thereby forming the plurality of servo strips on the recording surface. The index indicating the nonlinearity of the servo pattern is controlled to be below 15% of the track pitch. The track spacing is the distance between multiple tracks formed by recording data onto the magnetic tape by a recording element according to signals obtained from the plurality of servo patterns. The index represents the degree to which multiple PES difference gaps are discrete from the average value of the multiple PES difference gaps. The PES difference gap is the difference between the first PES difference and the second PES difference. The first PES difference is the difference in PES values ​​between a pair of corresponding first positions in the width direction of a pair of servo patterns recorded at corresponding positions in the width direction between a pair of servo bands that span more than one servo band in the width direction among the plurality of servo bands. The second PES difference is the difference in PES values ​​between a pair of second positions in the pair of servo patterns that are offset from the pair of first positions by a first predetermined interval in the width direction. The plurality of PES difference gaps are obtained by measuring the PES difference gaps at a second predetermined interval along the width direction in the pair of servo patterns. The first predetermined interval is greater than the second predetermined interval.

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