Servo pattern recording head, servo pattern recording device, magnetic tape, magnetic tape cartridge, magnetic tape drive, magnetic tape system, and method for manufacturing magnetic tape

Abstract

This servo pattern recording head comprises a plurality of magnetically separated head cores, and a plurality of gap patterns that are respectively formed on surfaces of the plurality of head cores and record a plurality of servo patterns in the width direction of a magnetic tape by applying a magnetic field to the magnetic tape in accordance with a pulse current, wherein the plurality of gap patterns are formed on the surfaces along the direction corresponding to the width direction, and the plurality of gap patterns are shifted at predetermined intervals in the direction corresponding to the longitudinal direction of the magnetic tape between adjacent gap patterns along the direction corresponding to the width direction.

Description

Servo pattern recording head, servo pattern recording device, magnetic tape, magnetic tape cartridge, magnetic tape drive, magnetic tape system, and method for manufacturing magnetic tape

[0001] The technology disclosed herein relates to a servo pattern recording head, a servo pattern recording device, a magnetic tape, a magnetic tape cartridge, a magnetic tape drive, a magnetic tape system, and a method for manufacturing a magnetic tape.

[0002] Japanese Patent Application Laid-Open No. 11-273040 discloses a method for determining position information on a linear data storage tape, which method includes the steps of writing a plurality of servo bands having similar longitudinal patterns of magnetic transitions along the length of the linear data storage tape, spacing the servo bands laterally across the linear data storage tape, and longitudinally offsetting one pattern from the other patterns to distinguish the servo bands from one another when reading and writing data laterally relative to the servo bands.

[0003] Japanese Patent Laid-Open Publication No. 2020-071896 discloses a servo pattern recording method. Patent Document 2 discloses a method for recording a servo pattern on a tape-shaped magnetic recording medium having a magnetic layer with five or more servo bands, which determines at least three first servo bands onto which first servo band identification information consisting of a plurality of bits is to be recorded and at least two second servo bands onto which second servo band identification information consisting of a plurality of bits different from the first servo band identification information is to be recorded, and records the first servo band identification information and the second servo band identification information in the same phase on the first servo bands and the second servo bands, respectively.

[0004] One embodiment of the technology disclosed herein provides a servo pattern recording head, a servo pattern recording device, a magnetic tape, a magnetic tape cartridge, a magnetic tape drive, a magnetic tape system, and a method for manufacturing a magnetic tape, which can contribute to identifying data bands and can reduce thermal effects (e.g., thermal contraction of the magnetic tape due to heat generation by the servo pattern recording head) and the occurrence of crosstalk when recording a servo pattern on the magnetic tape.

[0005] A first aspect of the technology of the present disclosure is a servo pattern recording head comprising a plurality of magnetically separated head cores and a plurality of gap patterns formed on the surface of each of the plurality of head cores, and which record a plurality of servo patterns in the width direction of the magnetic tape by applying a magnetic field to the magnetic tape in accordance with a pulse current, the plurality of gap patterns being formed on the surface along a direction corresponding to the width direction, and the plurality of gap patterns being offset at a predetermined interval in a direction corresponding to the longitudinal direction of the magnetic tape between adjacent gap patterns along the direction corresponding to the width direction.

[0006] A second aspect of the disclosed technique is the servo pattern recording head according to the first aspect, in which the information indicated by the pulse current includes identification information for identifying a plurality of servo patterns on a head core basis.

[0007] A third aspect of the technique of the present disclosure is the servo pattern recording head according to the second aspect, in which the identification information is common to each head core.

[0008] A fourth aspect of the disclosed technique is a servo pattern recording head according to any one of the first to third aspects, in which a plurality of gap patterns are arranged in common between head cores.

[0009] A fifth aspect according to the technique of the present disclosure is the servo pattern recording head according to any one of the first to fourth aspects, in which the pulse currents used in units of head cores are in phase.

[0010] A sixth aspect of the technology of the present disclosure is a servo pattern recording device comprising a servo pattern recording head according to any one of the first to fifth aspects and a pulse signal generator that supplies pulse current to a plurality of head cores, the pulse signal generator being provided for each of the plurality of head cores.

[0011] A seventh aspect of the technique of the present disclosure is a magnetic tape on which a servo pattern is recorded using the servo pattern recording head according to any one of the first to fifth aspects.

[0012] An eighth aspect of the technique of the present disclosure is a magnetic tape cartridge including the magnetic tape according to the seventh aspect and a case in which the magnetic tape is housed.

[0013] A ninth aspect of the technology of the present disclosure is a magnetic tape drive comprising a running mechanism that runs the magnetic tape of the seventh aspect along a predetermined path, and a magnetic head that reads a servo pattern on the predetermined path while the magnetic tape is running by the running mechanism.

[0014] A tenth aspect of the technology of the present disclosure is a magnetic tape system comprising a magnetic tape according to the seventh aspect and a magnetic tape drive equipped with a magnetic head that reads a servo pattern on a predetermined path while running the magnetic tape along the predetermined path.

[0015] An eleventh aspect of the technology of the present disclosure is a method for manufacturing a magnetic tape, which includes supplying a pulse current to a plurality of magnetically separated head cores, and recording a plurality of servo patterns in the width direction of the magnetic tape by applying a magnetic field to the magnetic tape in accordance with the pulse current via a plurality of gap patterns formed on the surface of each of the plurality of head cores, wherein the plurality of gap patterns are formed on the surface along a direction corresponding to the width direction, and the plurality of gap patterns are offset at a predetermined interval in a direction corresponding to the longitudinal direction of the magnetic tape between adjacent gap patterns along the direction corresponding to the width direction.

[0016] A twelfth aspect of the technology of the present disclosure is a method for manufacturing a magnetic tape according to the eleventh aspect, in which the information indicated by the pulse current includes identification information for identifying multiple servo patterns on a head core basis.

[0017] A thirteenth aspect of the disclosed technology is a magnetic tape having a plurality of sets of servo bands formed in the width direction, and a plurality of servo patterns arranged along the longitudinal direction of the servo bands, wherein pairs of corresponding servo patterns between the servo bands are offset at a predetermined interval in the longitudinal direction of the magnetic tape between adjacent servo bands in the width direction, and the servo patterns have set identification information recorded therein for identifying the corresponding sets.

[0018] A fourteenth aspect of the technique of the present disclosure is the magnetic tape according to the thirteenth aspect, wherein the set includes at least three or more servo bands.

[0019] 1 is a block diagram showing an example of the configuration of a magnetic tape system according to an embodiment. FIG. 2 is a schematic perspective view showing an example of the appearance of a magnetic tape cartridge according to an embodiment. FIG. 3 is a schematic configuration diagram showing an example of the hardware configuration of a magnetic tape drive according to an embodiment. FIG. 4 is a schematic perspective view showing an example of a mode in which a magnetic field is emitted by a non-contact read / write device from the underside of a magnetic tape cartridge according to an embodiment. FIG. 5 is a schematic configuration diagram showing an example of the hardware configuration of a magnetic tape drive according to an embodiment. FIG. 6 is a conceptual view showing an example of a mode in which a magnetic tape according to an embodiment is observed from the surface side of the magnetic tape. FIG. 7 is a conceptual view showing an example of a mode in which corresponding frames between adjacent servo bands in the width direction of the magnetic tape according to an embodiment are shifted by a predetermined interval, as observed from the surface side of the magnetic tape. FIG. 8 is a conceptual view showing an example of a mode in which servo patterns are read on the magnetic tape according to an embodiment by a servo read element included in a magnetic head, as observed from the surface side of the magnetic tape. FIG. 9 is a conceptual view showing an example of functions possessed by a control device included in a magnetic tape drive according to an embodiment. FIG. 10 is a conceptual view showing an example of processing content of a data band specifying unit included in a control device included in a magnetic tape drive according to an embodiment. FIG. 1 is a conceptual diagram showing an example of the processing contents of a control unit included in a control device included in a magnetic tape drive according to an embodiment. FIG. 1 is a conceptual diagram showing an example of a state in which a magnetic tape according to an embodiment is observed from the surface side of the magnetic tape before and after the width of the magnetic tape is contracted. FIG. 1 is a conceptual diagram showing an example of the processing contents of a position detection unit and control unit included in a control device included in a magnetic tape drive according to an embodiment. FIG. 1 is a conceptual diagram showing an example of the processing contents of a position detection unit and control unit included in a control device included in a magnetic tape drive according to an embodiment. FIG. 1 is a conceptual diagram showing an example of a state in which a servo pattern is read by a servo read element included in a magnetic head skewed above the magnetic tape according to an embodiment, observed from the surface side of the magnetic tape. FIG. 2 is a conceptual diagram showing an example of the configuration of a servo writer according to an embodiment.FIG. 1 is a conceptual diagram showing an example of the relationship between a pulse signal generator and a servo pattern recording head included in a servo writer according to an embodiment, and an example of a state in which the servo pattern recording head included in the servo writer according to the embodiment is arranged on a magnetic tape, observed from the surface side of the magnetic tape (i.e., the back side of the servo pattern recording head). FIG. 2 is a conceptual diagram showing an example of the relationship between a pulse signal generator and a servo pattern recording head included in a servo writer according to a first modified example, and an example of a state in which the servo pattern recording head included in the servo writer according to the embodiment is arranged on a magnetic tape, observed from the surface side of the magnetic tape (i.e., the back side of the servo pattern recording head). FIG. 3 is a conceptual diagram showing an example of the relationship between a pulse signal generator and a servo pattern recording head included in a servo writer according to a second modified example, and an example of a state in which the servo pattern recording head included in the servo writer according to the embodiment is arranged on a magnetic tape, observed from the surface side of the magnetic tape (i.e., the back side of the servo pattern recording head). FIG. 10 is a conceptual diagram showing an example of a magnetic tape according to a second modified example, observed from the surface side of the magnetic tape.

[0020] Below, examples of embodiments of a servo pattern recording device, magnetic tape, magnetic tape cartridge, magnetic tape drive, magnetic tape system, detection device, inspection device, servo pattern recording method, magnetic tape manufacturing method, detection method, and inspection method relating to the technology disclosed herein will be described with reference to the attached drawings.

[0021] First, the terms used in the following description will be explained.

[0022] NVM is an abbreviation for "Non-volatile memory". CPU is an abbreviation for "Central Processing Unit". RAM is an abbreviation for "Random Access Memory". EEPROM is an abbreviation for "Electrically Erasable and Programmable Read Only Memory". SSD is an abbreviation for "Solid State Drive". HDD is an abbreviation for "Hard Disk Drive". ASIC is an abbreviation for "Application Specific Integrated Circuit". FPGA is an abbreviation for "Field-Programmable Gate Array". PLC is an abbreviation for "Programmable Logic Controller". IC is an abbreviation for "Integrated Circuit". RFID is an abbreviation for "Radio Frequency IDentifier". BOT is an abbreviation for "Beginning Of Tape". EOT is an abbreviation for "End Of Tape". UI is an abbreviation for "User Interface." WAN is an abbreviation for "Wide Area Network." LAN is an abbreviation for "Local Area Network."

[0023] 1, as an example, a magnetic tape system 10 includes a magnetic tape cartridge 12 and a magnetic tape drive 14. The magnetic tape cartridge 12 is loaded into the magnetic tape drive 14. The magnetic tape cartridge 12 contains a magnetic tape MT. The magnetic tape drive 14 pulls out the magnetic tape MT from the loaded magnetic tape cartridge 12 and, while running the pulled-out magnetic tape MT, records data on the magnetic tape MT and reads data from the magnetic tape MT.

[0024] In this embodiment, the magnetic tape MT is an example of a "magnetic tape" according to the technology of the present disclosure. Also, in this embodiment, the magnetic tape system 10 is an example of a "magnetic tape system" according to the technology of the present disclosure. Also, in this embodiment, the magnetic tape drive 14 is an example of a "magnetic tape drive" according to the technology of the present disclosure. Also, in this embodiment, the magnetic tape cartridge 12 is an example of a "magnetic tape cartridge" according to the technology of the present disclosure.

[0025] Next, an example of the configuration of the magnetic tape cartridge 12 will be described with reference to Figures 2 to 4. For convenience of explanation, in the following description, the loading direction of the magnetic tape cartridge 12 into the magnetic tape drive 14 is indicated by arrow A in Figures 2 to 4, the direction of arrow A is the front direction of the magnetic tape cartridge 12, and the front side of the magnetic tape cartridge 12 is the front side of the magnetic tape cartridge 12. In the following description of the structure, "front" refers to the front side of the magnetic tape cartridge 12.

[0026] 2 to 4, for convenience of explanation, the direction of arrow B, which is orthogonal to the direction of arrow A, is defined as the right direction, and the right side of the magnetic tape cartridge 12 is defined as the right side of the magnetic tape cartridge 12. In the following description of the structure, "right" refers to the right side of the magnetic tape cartridge 12.

[0027] 2 to 4, for convenience of explanation, the direction opposite to the direction of arrow B is referred to as the left direction, and the left side of the magnetic tape cartridge 12 is referred to as the left side of the magnetic tape cartridge 12. In the following description of the structure, "left" refers to the left side of the magnetic tape cartridge 12.

[0028] 2 to 4, for convenience of explanation, the direction perpendicular to the directions of arrows A and B is indicated by arrow C, the direction of arrow C is the upward direction of the magnetic tape cartridge 12, and the upward side of the magnetic tape cartridge 12 is the upper side of the magnetic tape cartridge 12. In the explanation of the structure shown below, "upper" refers to the upper side of the magnetic tape cartridge 12.

[0029] 2 to 4, for convenience of explanation, the direction opposite to the front direction of the magnetic tape cartridge 12 is referred to as the rear direction of the magnetic tape cartridge 12, and the rear side of the magnetic tape cartridge 12 is referred to as the rear side of the magnetic tape cartridge 12. In the following description of the structure, "rear" refers to the rear side of the magnetic tape cartridge 12.

[0030] 2 to 4, for convenience of explanation, the direction opposite to the upper direction of the magnetic tape cartridge 12 is referred to as the lower direction of the magnetic tape cartridge 12, and the lower side of the magnetic tape cartridge 12 is referred to as the lower side of the magnetic tape cartridge 12. In the following description of the structure, "lower" refers to the lower side of the magnetic tape cartridge 12.

[0031] As shown in FIG. 2 as an example, the magnetic tape cartridge 12 has a box-shaped case 16 that is generally rectangular in plan view. The case 16 is an example of a "case" according to the technology of the present disclosure. The magnetic tape MT is housed in the case 16. The case 16 is made of a resin such as polycarbonate and has an upper case 18 and a lower case 20. The upper case 18 and the lower case 20 are joined by welding (e.g., ultrasonic welding) and screw fastening, with the lower peripheral surface of the upper case 18 and the upper peripheral surface of the lower case 20 in contact with each other. The joining method is not limited to welding and screw fastening, and other joining methods may also be used.

[0032] The supply reel 22 is rotatably housed inside the case 16. The supply reel 22 includes a reel hub 22A, an upper flange 22B1, and a lower flange 22B2. The reel hub 22A is cylindrical. The reel hub 22A is the axial center of the supply reel 22, and its axial direction is aligned with the vertical direction of the case 16, and it is disposed in the center of the case 16. The upper flange 22B1 and the lower flange 22B2 are each formed in an annular shape. The center of the upper flange 22B1 in a plan view is fixed to the upper end of the reel hub 22A, and the center of the lower flange 22B2 in a plan view is fixed to the lower end of the reel hub 22A. The reel hub 22A and the lower flange 22B2 may be integrally molded.

[0033] The magnetic tape MT is wound around the outer peripheral surface of the reel hub 22A, and the widthwise ends of the magnetic tape MT are held by an upper flange 22B1 and a lower flange 22B2.

[0034] An opening 16B is formed in the front side of the right wall 16A of the case 16. The magnetic tape MT is pulled out through the opening 16B.

[0035] The lower case 20 is provided with a cartridge memory 24. Specifically, the cartridge memory 24 is housed in the right rear end portion of the lower case 20. An IC chip having an NVM is mounted on the cartridge memory 24. In this embodiment, a so-called passive RFID tag is used as the cartridge memory 24, and various information is read and written to the cartridge memory 24 in a contactless manner.

[0036] The cartridge memory 24 stores management information for managing the magnetic tape cartridge 12. The management information includes, for example, information about the cartridge memory 24 (for example, information that can identify the magnetic tape cartridge 12), information about the magnetic tape MT (for example, information indicating the recording capacity of the magnetic tape MT, information indicating an overview of the data recorded on the magnetic tape MT, information indicating the items of data recorded on the magnetic tape MT, and information indicating the recording format of the data recorded on the magnetic tape MT), and information about the magnetic tape drive 14 (for example, information indicating the specifications of the magnetic tape drive 14 and signals used in the magnetic tape drive 14).

[0037] 3, the magnetic tape drive 14 includes a transport device 26, a magnetic head 28, a control device 30, storage 32, a UI device 34, and a communication interface 35. The magnetic tape cartridge 12 is loaded into the magnetic tape drive 14 in the direction of arrow A. In the magnetic tape drive 14, the magnetic tape MT is pulled out from the magnetic tape cartridge 12 and used.

[0038] The magnetic tape MT includes a magnetic layer 29A, a base film 29B, and a backcoat layer 29C. The magnetic layer 29A is formed on one side of the base film 29B, and the backcoat layer 29C is formed on the other side of the base film 29B. Data is recorded in the magnetic layer 29A. The magnetic layer 29A contains ferromagnetic powder. Examples of the ferromagnetic powder include ferromagnetic powders commonly used in the magnetic layers of various magnetic recording media. A preferred example of the ferromagnetic powder is hexagonal ferrite powder. Examples of the hexagonal ferrite powder include hexagonal strontium ferrite powder and hexagonal barium ferrite powder. The backcoat layer 29C is a layer containing a non-magnetic powder such as carbon black. The base film 29B, also referred to as a support, is formed of, for example, polyethylene terephthalate, polyethylene naphthalate, or polyamide. A non-magnetic layer may be formed between the base film 29B and the magnetic layer 29A. In the magnetic tape MT, the surface on which the magnetic layer 29A is formed is the front surface 31 of the magnetic tape MT, and the surface on which the backcoat layer 29C is formed is the back surface 33 of the magnetic tape MT.

[0039] The magnetic tape drive 14 performs magnetic processing on the surface 31 of the magnetic tape MT using the magnetic head 28. Here, magnetic processing refers to recording data on the surface 31 of the magnetic tape MT and reading data from the surface 31 of the magnetic tape MT (i.e., reproducing data). In this embodiment, the magnetic tape drive 14 selectively records data on the surface 31 of the magnetic tape MT and reads data from the surface 31 of the magnetic tape MT using the magnetic head 28. That is, the magnetic tape drive 14 pulls out the magnetic tape MT from the magnetic tape cartridge 12 and uses the magnetic head 28 to record data on the surface 31 of the pulled-out magnetic tape MT or reads data from the surface 31 of the pulled-out magnetic tape MT using the magnetic head 28.

[0040] The control device 30 controls the entire magnetic tape drive 14. In this embodiment, the control device 30 is realized by an ASIC, but the technology of the present disclosure is not limited to this. For example, the control device 30 may be realized by an FPGA and / or a PLC. The control device 30 may also be realized by a computer including a CPU, flash memory (e.g., EEPROM and / or SSD), and RAM. The control device 30 may also be realized by a combination of two or more of the ASIC, FPGA, PLC, and computer. In other words, the control device 30 may be realized by a combination of hardware and software.

[0041] The storage 32 is connected to the control device 30, and the control device 30 writes various types of information to the storage 32 and reads various types of information from the storage 32. Examples of the storage 32 include a flash memory and / or a HDD. The flash memory and the HDD are merely examples, and any non-volatile memory that can be mounted in the magnetic tape drive 14 may be used.

[0042] The UI device 34 is a device having a reception function for receiving instruction signals indicating instructions from a user and a presentation function for presenting information to the user. The reception function is realized by, for example, a touch panel, hard keys (e.g., a keyboard), and / or a mouse. The presentation function is realized by, for example, a display, a printer, and / or a speaker. The UI device 34 is connected to the control device 30. The control device 30 acquires the instruction signals received by the UI device 34. The UI device 34 presents various information to the user under the control of the control device 30.

[0043] The communication interface 35 is connected to the control device 30. The communication interface 35 is also connected to an external device 37 via a communication network (not shown) such as a WAN and / or LAN. The communication interface 35 controls the exchange of various information (e.g., data to be recorded on the magnetic tape MT, data read from the magnetic tape MT, and / or instruction signals given to the control device 30) between the control device 30 and the external device 37. The external device 37 may be, for example, a personal computer or a mainframe.

[0044] The transport device 26 is a device that selectively transports the magnetic tape MT in the forward direction or the reverse direction along a predetermined path, and includes a feed motor 36, a take-up reel 38, a take-up motor 40, and multiple guide rollers GR. Note that the forward direction here refers to the feed direction of the magnetic tape MT, and the reverse direction refers to the rewind direction of the magnetic tape MT. In this embodiment, the transport device 26 is an example of a "travel mechanism" according to the technology of the present disclosure.

[0045] The supply motor 36 rotates the supply reel 22 in the magnetic tape cartridge 12 under the control of the control device 30. The control device 30 controls the supply motor 36 to control the rotation direction, rotation speed, rotation torque, etc. of the supply reel 22.

[0046] The take-up motor 40 rotates the take-up reel 38 under the control of the control device 30. The control device 30 controls the take-up motor 40 to control the rotation direction, rotation speed, rotation torque, etc. of the take-up reel 38.

[0047] When the magnetic tape MT is wound by the take-up reel 38, the control device 30 rotates the supply motor 36 and the take-up motor 40 so that the magnetic tape MT runs in the forward direction along a predetermined path. The rotational speed, rotational torque, etc. of the supply motor 36 and the take-up motor 40 are adjusted according to the speed at which the magnetic tape MT is wound around the take-up reel 38. Furthermore, tension is applied to the magnetic tape MT by the control device 30 adjusting the rotational speed, rotational torque, etc. of the supply motor 36 and the take-up motor 40. Furthermore, the tension applied to the magnetic tape MT is controlled by the control device 30 adjusting the rotational speed, rotational torque, etc. of the supply motor 36 and the take-up motor 40.

[0048] When the magnetic tape MT is rewound onto the supply reel 22, the control device 30 rotates the supply motor 36 and the take-up motor 40 so that the magnetic tape MT runs in the reverse direction along the predetermined path.

[0049] In this embodiment, the tension applied to the magnetic tape MT is controlled by controlling the rotation speed and rotation torque of the supply motor 36 and the take-up motor 40, but the technology of the present disclosure is not limited to this. For example, the tension applied to the magnetic tape MT may be controlled using a dancer roller, or may be controlled by drawing the magnetic tape MT into a vacuum chamber.

[0050] Each of the plurality of guide rollers GR is a roller that guides the magnetic tape MT. The predetermined path, i.e., the running path of the magnetic tape MT, is determined by disposing the plurality of guide rollers GR at positions across the magnetic head 28 between the magnetic tape cartridge 12 and the take-up reel 38.

[0051] The magnetic head 28 includes a magnetic element unit 42 and a holder 44. The magnetic element unit 42 is held by the holder 44 so as to come into contact with the running magnetic tape MT. The magnetic element unit 42 has a plurality of magnetic elements.

[0052] The magnetic element unit 42 records data on the magnetic tape MT transported by the transport device 26, and reads data from the magnetic tape MT transported by the transport device 26. Here, data refers to, for example, the servo patterns 58 (see FIG. 9) and data other than the servo patterns 58, i.e., data recorded in the data band DB (see FIG. 9).

[0053] The magnetic tape drive 14 is equipped with a non-contact read / write device 46. The non-contact read / write device 46 is disposed below the magnetic tape cartridge 12 when the magnetic tape cartridge 12 is loaded so as to directly face the back surface 24A of the cartridge memory 24, and reads and writes information from and to the cartridge memory 24 in a non-contact manner.

[0054] 4, the non-contact read / write device 46 emits a magnetic field MF from the bottom side of the magnetic tape cartridge 12 toward the cartridge memory 24. The magnetic field MF penetrates the cartridge memory 24.

[0055] The non-contact read / write device 46 is connected to the control device 30. The control device 30 outputs a control signal to the non-contact read / write device 46. The control signal is a signal that controls the cartridge memory 24. The non-contact read / write device 46 generates a magnetic field MF in accordance with the control signal input from the control device 30, and emits the generated magnetic field MF toward the cartridge memory 24.

[0056] The non-contact type read / write device 46 performs contactless communication with the cartridge memory 24 via the magnetic field MF, and performs processing on the cartridge memory 24 in accordance with the control signal. For example, under the control of the control device 30, the non-contact type read / write device 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).

[0057] 5, the magnetic tape drive 14 includes a movement mechanism 48. The movement mechanism 48 has a movement actuator 48A. Examples of the movement actuator 48A include a voice coil motor and / or a piezoelectric actuator. The movement actuator 48A is connected to the control device 30, which controls the movement actuator 48A. The movement actuator 48A generates power under the control of the control device 30. The movement mechanism 48 receives the power generated by the movement actuator 48A to move the magnetic head 28 in the width direction of the magnetic tape MT.

[0058] The magnetic tape drive 14 is equipped with a tilt mechanism 49. The tilt mechanism 49 has a tilt actuator 49A. Examples of the tilt actuator 49A include a voice coil motor and / or a piezoelectric actuator. The tilt actuator 49A is connected to the control device 30, which controls the tilt actuator 49A. The tilt actuator 49A generates power under the control of the control device 30. By receiving the power generated by the tilt actuator 49A, the tilt mechanism 49 tilts the magnetic head 28 toward the longitudinal direction LD of the magnetic tape MT with respect to the width direction WD (see FIG. 17 ). In other words, the magnetic head 28 is skewed on the magnetic tape MT under the control of the control device 30.

[0059] 6, servo bands SB1, SB2, SB3, and SB4 and data bands DB1, DB2, and DB3 are formed on the surface 31 of the magnetic tape MT. The servo bands SB1 to SB4 are examples of "servo bands" according to the technology of the present disclosure. Note that, for convenience of explanation, the servo bands SB1 to SB4 will be referred to as servo bands SB, and the data bands DB1 to DB3 will be referred to as data bands DB, unless a distinction is particularly needed.

[0060] The servo bands SB1 to SB4 and the data bands DB1 to DB3 are formed along the longitudinal direction LD (i.e., the overall length direction) of the magnetic tape MT. Here, the overall length direction LD of the magnetic tape MT refers to the running direction of the magnetic tape MT. The running direction of the magnetic tape MT is defined as two directions: the forward direction (hereinafter also simply referred to as the "forward direction") in which the magnetic tape MT runs from the supply reel 22 side to the take-up reel 38 side, and the reverse direction (hereinafter also simply referred to as the "reverse direction") in which the magnetic tape MT runs from the take-up reel 38 side to the supply reel 22 side.

[0061] The servo bands SB1 to SB4 are arranged at positions spaced apart in the width direction WD of the magnetic tape MT (hereinafter also simply referred to as the "width direction WD"). For example, the servo bands SB1 to SB4 are arranged at equal intervals along the width direction WD. In this embodiment, "equal intervals" refers not only to perfectly equal intervals, but also to equal intervals that include an error that is generally acceptable in the technical field to which the technology of the present disclosure belongs and that does not contradict the spirit of the technology of the present disclosure.

[0062] Data band DB1 is arranged between servo band SB1 and servo band SB2, and data band DB2 is arranged between servo band SB2 and servo band SB3. Data band DB3 is arranged between servo band SB3 and servo band SB4. In other words, servo bands SB and data bands DB are arranged alternately along the width direction WD.

[0063] 6 shows four servo bands SB and three data bands DB for ease of explanation, but this is merely an example, and two servo bands SB and one data band DB may be used, or three servo bands and two data bands may be used.Furthermore, the technology of the present disclosure is also applicable to five or more servo bands SB and four or more data bands DB.

[0064] A plurality of servo patterns 58 are recorded on the servo band SB along the longitudinal direction LD of the magnetic tape MT. The servo patterns 58 are classified into servo patterns 58A and servo patterns 58B. The plurality of servo patterns 58 are arranged at regular intervals along the longitudinal direction LD of the magnetic tape MT. In this embodiment, "constant" refers not only to perfect uniformity but also to uniformity that includes an error that is generally acceptable in the technical field to which the technology of the present disclosure pertains and that does not contradict the spirit of the technology of the present disclosure.

[0065] The servo band SB is separated by a plurality of frames 56 along the longitudinal direction LD of the magnetic tape MT. Each frame 56 is defined by a set of servo patterns 58. In the example shown in Fig. 6, servo patterns 58A and 58B are shown as an example of a set of servo patterns 58. The servo patterns 58A and 58B are adjacent to each other along the longitudinal direction LD of the magnetic tape MT, and within the frame 56, the servo pattern 58A is located on the upstream side in the forward direction, and the servo pattern 58B is located on the downstream side in the forward direction.

[0066] The servo pattern 58 is made up of linear magnetization region pairs 60. The linear magnetization region pairs 60 are classified into linear magnetization region pairs 60A and linear magnetization region pairs 60B.

[0067] The servo pattern 58A is made up of a pair of linear magnetization regions 60A. In the example shown in Fig. 6, linear magnetization regions 60A1 and 60A2 are shown as an example of the pair of linear magnetization regions 60A. Each of the linear magnetization regions 60A1 and 60A2 is a linearly magnetized region.

[0068] The linear magnetization regions 60A1 and 60A2 are inclined in opposite directions with respect to a virtual line C1, which is a virtual line along the width direction WD. In the example shown in Fig. 6, the linear magnetization regions 60A1 and 60A2 are inclined in line symmetry with respect to the virtual line C1. More specifically, the linear magnetization regions 60A1 and 60A2 are formed non-parallel to each other and inclined at a predetermined angle (e.g., 5 degrees) in opposite directions on the longitudinal direction LD side of the magnetic tape MT with the virtual line C1 as the axis of symmetry.

[0069] The linear magnetization region 60A1 is a set of five magnetized straight lines 60A1a, and the linear magnetization region 60A2 is a set of five magnetized straight lines 60A2a.

[0070] The servo pattern 58B is made up of a pair of linear magnetization regions 60B. In the example shown in Fig. 6, linear magnetization regions 60B1 and 60B2 are shown as an example of the pair of linear magnetization regions 60B. Each of the linear magnetization regions 60B1 and 60B2 is a linearly magnetized region.

[0071] The linear magnetization regions 60B1 and 60B2 are inclined in opposite directions with respect to a virtual line C2, which is a virtual line along the width direction WD. In the example shown in Fig. 6, the linear magnetization regions 60B1 and 60B2 are inclined in line symmetry with respect to the virtual line C2. More specifically, the linear magnetization regions 60B1 and 60B2 are formed non-parallel to each other and inclined at a predetermined angle (e.g., 5 degrees) in opposite directions on the longitudinal direction LD side of the magnetic tape MT with the virtual line C2 as the axis of symmetry.

[0072] The linear magnetization region 60B1 is a set of four magnetized straight lines 60B1a, and the linear magnetization region 60B2 is a set of four magnetized straight lines 60B2a.

[0073] The magnetic head 28 is disposed on the surface 31 side of the magnetic tape MT configured in this manner. The holder 44 is formed in a rectangular parallelepiped shape and is disposed so as to traverse the surface 31 of the magnetic tape MT in the width direction WD. The multiple magnetic elements of the magnetic element unit 42 are linearly arranged along the longitudinal direction LD of the holder 44. The magnetic element unit 42 has, as its multiple magnetic elements, a pair of servo read elements SR and multiple data read / write elements DRW. The longitudinal length of the holder 44 is sufficiently long relative to the width of the magnetic tape MT. For example, the longitudinal length of the holder 44 is set to be longer than the width of the magnetic tape MT regardless of the position of the magnetic element unit 42 on the magnetic tape MT.

[0074] The pair of servo read elements SR consists of servo read elements SR1 and SR2. The servo read element SR1 is disposed at one end of the magnetic element unit 42, and the servo read element SR2 is disposed at the other end of the magnetic element unit 42. In the example shown in Figure 6, the servo read element SR1 is provided at a position corresponding to the servo band SB2, and the servo read element SR2 is provided at a position corresponding to the servo band SB3.

[0075] The plurality of data read / write elements DRW are arranged linearly between the servo read element SR1 and the servo read element SR2. The plurality of data read / write elements DRW are arranged at intervals along the longitudinal direction of the magnetic head 28 (for example, at equal intervals along the longitudinal direction of the magnetic head 28). In the example shown in FIG. 6, the plurality of data read / write elements DRW are provided at positions corresponding to the data band DB3.

[0076] The control device 30 acquires a servo signal resulting from the servo read element SR reading the servo pattern 58, and performs servo control in accordance with the acquired servo signal. Here, servo control refers to control that moves the magnetic head 28 in the width direction WD of the magnetic tape MT by operating the movement mechanism 48 in accordance with the servo pattern 58 read by the servo read element SR.

[0077] By performing servo control, the plurality of data read / write elements DRW are positioned on a designated area in the data band DB, and perform magnetic processing on the designated area in the data band DB. In the example shown in Fig. 6, the plurality of data read / write elements DRW perform magnetic processing on the designated area in the data band DB2.

[0078] Furthermore, when the data band DB from which the magnetic element unit 42 reads data is changed (in the example shown in FIG. 6 , when the data band DB from which the magnetic element unit 42 reads data is changed from data band DB2 to data band DB1), the movement mechanism 48, under the control of the control device 30, moves the magnetic head 28 in the width direction WD to change the positions of the pair of servo read elements SR. That is, by moving the magnetic head 28 in the width direction WD, the movement mechanism 48 moves the servo read element SR1 to a position corresponding to servo band SB1 and moves the servo read element SR2 to a position corresponding to servo band SB2. As a result, the positions of the multiple data read / write elements DRW are changed from on data band DB2 to on data band DB1, and the multiple data read / write elements DRW perform magnetic processing on data band DB1.

[0079] The same control is also performed when the data band DB from which the magnetic element unit 42 reads data is changed from data band DB2 to data band DB3. The same control is also performed when the data band DB from which the magnetic element unit 42 reads data is changed from data band DB1 to data band DB3.

[0080] Recently, as the recording capacity of magnetic tape MT increases in density, there is a demand for an increased number of data bands DB. As the number of data bands DB increases, the number of servo bands SB also increases. In this case, it is difficult to form a magnetic head 28 with numerous relative displacements (i.e., deviations at predetermined intervals) between the servo patterns 58, as this would affect the recording performance of the magnetic head 28. In other words, an increase in the predetermined intervals leads to an increase in the width of the magnetic head 28 (i.e., the length along the running direction of the magnetic tape MT). This, in turn, leads to an increase in the width of the sub-gap (i.e., the substrate supporting the surface WH1A on which the gap pattern G is formed), resulting in a decrease in recording performance. Furthermore, in the case of a magnetic head 28 that does not have relative displacement, a pulse signal generator SW4 (see FIG. 18) corresponding to the number of servo bands SB is required, which increases the current supplied to the entire magnetic head 28, resulting in heat generation and / or a smaller distance between the servo bands SB (i.e., the spacing between the servo bands SB), which can cause problems with crosstalk (i.e., a phenomenon in which the magnetic field formed by a pulse current supplied to one head core WH (see FIG. 19) of the magnetic head 28 is superimposed on the adjacent head core WH2 (see FIG. 19), causing an unintended signal to be recorded). Furthermore, an increase in the number of facilities that generate pulse currents also leads to the problem of increased costs for production facilities.

[0081] Therefore, as shown in FIG. 7 as an example, information ID (hereinafter also simply referred to as "identification information ID") for identifying the servo band SB is embedded in each servo pattern 58. In the example shown in FIG. 7, by modulating the pulse signal for the servo pattern 58A in the servo band SB4, the interval between the third magnetization line 60A1a and the second magnetization line 60A1a (hereinafter referred to as the "first interval") and the interval between the third magnetization line 60A1a and the fourth magnetization line 60A1a (hereinafter referred to as the "second interval") can be changed for each servo pattern 58A. In the example shown in FIG. 7, the first interval and the second interval are exaggerated to make them easier to visually grasp. By varying the first interval and the second interval for each servo pattern 58A, it is possible to embed at least one bit of information in each frame 56. This makes it possible to embed identification information ID1 by combining multiple frames 56. As a result, the identification information ID1 is obtained when the servo read element SR reads the plurality of servo patterns 58. The identification information ID and the identification information ID1 are examples of "identification information" according to the technology of the present disclosure.

[0082] Although not shown, in the servo band SB3, as in the servo band SB4, the pulse signal for the servo pattern 58A is modulated, so that the first interval and the second interval among the five magnetization lines 60A1a can be changed for each servo pattern 58A. This makes it possible to embed the identification information ID1 by combining a plurality of frames 56.

[0083] Here, the servo bands SB3 and SB4 form one servo band set SBP1. In other words, the servo band set SBP1 includes a pair of servo bands SB3 and SB4. The identification information ID1 recorded in the servo pattern 58A of the servo band SB3 and the servo pattern 58A of the servo band SB4 is the same.

[0084] In the example shown in FIG. 7 , the pulse signal for the servo pattern 58A is modulated in the servo band SB2, thereby changing the distance between the first and second magnetization lines 60A1a (hereinafter referred to as the "third distance") and the distance between the fourth and fifth magnetization lines 60A1a (hereinafter referred to as the "third distance") for each servo pattern 58A. In the example shown in FIG. 7 , the third and fourth distances are exaggerated to make them easier to visualize. By varying the third and fourth distances for each servo pattern 58A, it is possible to embed at least one bit of information in each frame 56. This makes it possible to embed identification information ID2 by combining multiple frames 56. As a result, when multiple servo patterns 58 are read by the servo read element SR, the identification information ID2 is obtained. The identification information ID2 is an example of "identification information" according to the technology of the present disclosure.

[0085] Although not shown, in the servo band SB1, as in the servo band SB2, the pulse signal for the servo pattern 58A is modulated, so that the third and fourth intervals among the five magnetization lines 60A1a can be changed for each servo pattern 58A. This makes it possible to embed the identification information ID2 by combining a plurality of frames 56.

[0086] The servo bands SB1 and SB2 form another set of servo bands SBP2. In other words, the set of servo bands SBP2 includes a pair of servo bands SB1 and SB2. The identification information ID2 recorded in the servo patterns 58A of the servo bands SB1 and SB2 is common to both the servo patterns 58A of the servo bands SB1 and SB2.

[0087] As described above, the identification information ID1 recorded in the servo pattern 58A of the servo band SB3 and the servo pattern 58A of the servo band SB4 is common. Furthermore, the servo band SB3 and the servo band SB4 form a set SBP1 of servo bands. Therefore, the identification information ID1 can also be said to be information PID1 for identifying the set SBP1 (hereinafter also simply referred to as "set identification information PID1").

[0088] As described above, the identification information ID2 recorded in the servo pattern 58A of the servo band SB1 and the servo pattern 58A of the servo band SB2 is the same. Furthermore, the servo band SB1 and the servo band SB2 form a set SBP2 of servo bands. Therefore, the identification information ID2 can also be said to be information PID2 for identifying the set SBP2 (hereinafter simply referred to as "set identification information PID2," and when there is no need to distinguish between the set identification information PID1 and PID2, also referred to as "set identification information PID"). In this way, the set identification information PID is recorded in the servo pattern 58. The set identification information PID is an example of "set identification information" according to the technology of the present disclosure.

[0089] In addition to the identification information ID, various information may be embedded in the servo pattern 58A. The various information may include, for example, information about the position in the longitudinal direction LD and / or information specifying the manufacturer of the magnetic tape MT, etc. In this case, the information also refers to a pulse signal.

[0090] 8, a plurality of servo bands SB are formed on the magnetic tape MT in the width direction WD, and the frames 56 corresponding to each other between the servo bands SB are offset by a predetermined interval in the longitudinal direction LD between adjacent servo bands SB in the width direction WD. This means that the servo patterns 58 corresponding to each other between the servo bands SB are offset by a predetermined interval in the longitudinal direction LD between adjacent servo bands SB in the width direction WD. The predetermined interval is a predetermined value (for example, a value determined based on the specifications of the magnetic tape MT).

[0091] Although the present embodiment has been described with reference to an example in which the predetermined interval is determined, the predetermined interval may be determined as follows. For example, the predetermined interval is determined based on the angle α, the pitch between adjacent servo bands SB in the width direction WD (hereinafter also referred to as the "servo band pitch"), and the frame length. In the example shown in FIG. 8, the angle α is exaggerated to make it easier to visually grasp the angle α, but in reality, the angle α is, for example, approximately 15 degrees. The angle α is the angle formed by the virtual line C1 and the frames 56 that do not have a corresponding relationship between adjacent servo bands SB in the width direction WD. In the example shown in Figure 8, an example of the angle α is the angle formed between one frame 56 of a pair of frames 56 that correspond to each other between adjacent servo bands SB in the width direction WD (in the example shown in Figure 8, one frame 56 of servo band SB3) and the frame 56 adjacent to the other frame 56 of the pair of frames 56 (in the example shown in Figure 8, one frame 56 of servo band SB2 that corresponds to one frame 56 of servo band SB3) (in the example shown in Figure 8, line segment L1) and the virtual straight line C1.

[0092] In addition, in the example shown in Figure 8, an example of the angle α is the angle formed between one frame 56 of a pair of frames 56 that correspond to each other between adjacent servo bands SB in the width direction WD (in the example shown in Figure 8, one frame 56 of servo band SB1) and the frame 56 adjacent to the other frame 56 of the pair of frames 56 (in the example shown in Figure 8, one frame 56 of servo band SB4 that corresponds to one frame 56 of servo band SB3) (in the example shown in Figure 8, line segment L2) and the virtual straight line C1.

[0093] The frame length refers to the total length of the frame 56 in the longitudinal direction LD. The predetermined interval is defined by the following formula (1): Mod(A / B) denotes the remainder when "A" is divided by "B".

[0094] (Predetermined interval) = Mod{(servo band pitch × tan α) / (frame length)} (1)

[0095] In the example shown in FIG. 8 , the angle α is the angle formed by the virtual line C1 between one frame 56 (hereinafter also referred to as the “first frame”) of a pair of frames 56 corresponding to each other in the width direction WD and the frame 56 adjacent to the other frame 56 (hereinafter also referred to as the “second frame”) of the pair of frames 56. However, the technology disclosed herein is not limited to this. For example, the angle α may be the angle formed by the virtual line C1 between the first corresponding frame and a frame 56 (hereinafter also referred to as the “third frame”) that is two or more frames away from the second frame within the same servo band SB as the second frame. In this case, the “frame length” used in equation (1) is the pitch between the second frame and the third frame in the longitudinal direction LD (e.g., the distance from the leading edge of the second frame to the leading edge of the third frame).

[0096] 9, when the servo read element SR reads the servo patterns 58A and 58B (i.e., the pair of linear magnetized regions 60A and 60B), a servo signal derived from the linear magnetized regions 60A and 60B is obtained. As described above, the servo pattern 58A of each servo band SB has identification information ID recorded therein. Also, as described above, the corresponding servo patterns 58 between the servo bands SB are shifted at a predetermined interval in the longitudinal direction LD between the servo bands SB adjacent in the width direction WD.

[0097] Therefore, the servo signal obtained by reading each servo band SB reflects the identification information ID recorded in the servo pattern 58A of each servo band SB and the deviation of the predetermined interval. In the example shown in Figure 9, the servo signal obtained by reading the servo band SB4 (hereinafter also referred to as the "fourth servo signal SBS4") and the servo signal obtained by reading the servo band SB3 (hereinafter also referred to as the "third servo signal SBS3") have different phases, reflecting the deviation of the predetermined interval. Specifically, when the magnetic tape MT is run in the forward direction, the fourth servo signal SBS4 is detected later than the third servo signal SBS3 by a time t1 corresponding to the predetermined interval.

[0098] Furthermore, the third servo signal SBS3 and the servo signal obtained by reading the servo band SB2 (hereinafter also referred to as the "second servo signal SBS2") have different phases, reflecting the difference in the predetermined interval. Specifically, when the magnetic tape MT is run in the forward direction, the third servo signal SBS3 is detected earlier than the second servo signal SBS2 by a time t1 corresponding to the predetermined interval. Furthermore, the identification information ID1 indicated by the third servo signal SBS3 is different from the identification information ID2 indicated by the second servo signal SBS2. Specifically, the pulse interval corresponding to the linear magnetized region pair 60A in the third servo signal SBS3 is different from the pulse interval corresponding to the linear magnetized region pair 60A in the second servo signal SBS2.

[0099] Furthermore, the second servo signal SBS2 and the servo signal obtained by reading the servo band SB1 (hereinafter also referred to as the "first servo signal SBS1") have different phases, reflecting the difference in the predetermined interval. Specifically, when the magnetic tape MT is run in the forward direction, the first servo signal SBS1 is detected earlier than the second servo signal SBS2 by a time t2 corresponding to the predetermined interval.

[0100] 10, the control device 30 includes a control unit 30A and a data band identification unit 30B. The data band identification unit 30B includes a first identification unit 30B1 and a second identification unit 30B2. The data band identification unit 30B acquires a servo signal resulting from the servo read element SR reading the servo pattern 58 in the servo band SB, and identifies the data band DB based on the acquired servo signal.

[0101] The first specifying unit 30B1 acquires the result of reading the servo pattern 58 by the servo read element SR1, and the second specifying unit 30B2 acquires the result of reading the servo pattern 58 by the servo read element SR2.

[0102] 10, the first specifying unit 30B1 acquires a third servo signal SBS3 obtained by the servo read element SR1 reading the servo pattern 58 in the servo band SB3, and the second specifying unit 30B2 acquires a fourth servo signal SBS4 obtained by the servo read element SR2 reading the servo pattern 58 in the servo band SB3.

[0103] As an example, as shown in FIG. 11, the data band identification unit 30B identifies the data band DB based on the third servo signal SBS3 and the fourth servo signal SBS4 acquired by the first identification unit 30B1 and the second identification unit 30B2, respectively.

[0104] Specifically, the data band identification unit 30B acquires the identification information ID from the third servo signal SBS3 and the fourth servo signal SBS4 using an autocorrelation coefficient. The data band identification unit 30B also calculates the offset amount OS, which indicates the deviation of the predetermined interval, from the first servo signal SBS3 and the fourth servo signal SBS4 using an autocorrelation coefficient.

[0105] An ideal waveform signal 66 is stored in the storage 32. The ideal waveform signal 66 is a signal indicating a single ideal waveform included in the servo signal (for example, an ideal signal resulting from reading one of the ideal magnetization lines included in the servo pattern 58 by the servo read element SR). The ideal waveform signal 66 can also be considered a sample signal to be compared with the servo signal. Note that while an example in which the ideal waveform signal 66 is stored in the storage 32 is given here, this is merely an example. For example, the ideal waveform signal 66 may be stored in the cartridge memory 24 instead of or in addition to the storage 32. The ideal waveform signal 66 may also be recorded in a BOT area (not shown) provided at the beginning of the magnetic tape MT and / or an EOT area (not shown) provided at the end of the magnetic tape MT.

[0106] The autocorrelation coefficient used by the data band identification unit 30B is a coefficient that indicates the degree of correlation between the servo signal and the ideal waveform signal 66. The data band identification unit 30B acquires the ideal waveform signal 66 from the storage 32 and compares the acquired ideal waveform signal 66 with the servo signal. The data band identification unit 30B then calculates the autocorrelation coefficient based on the comparison result. The data band identification unit 30B detects positions on the servo band SB where the correlation between the servo signal and the ideal waveform signal 66 is high (for example, positions where the servo signal and the ideal waveform signal 66 match) according to the autocorrelation coefficient.

[0107] The data band identification unit 30B acquires the identification information ID, for example, as follows. As described above, when recording the servo patterns 58A, the first interval and the second interval are made different for each servo pattern 58A, thereby embedding the identification information ID (i.e., the group identification information PID). Therefore, the data band identification unit 30B acquires the identification information ID based on the pulse waveform detected according to the autocorrelation coefficient. That is, the data band identification unit 30B distinguishes the servo patterns 58 included in the servo band SB from the shape of the pulse waveform. Then, the data band identification unit 30B reads out the identification information ID based on the combination of the servo patterns 58 included in the servo band SB. In the example shown in FIG. 11 , the identification information ID1 is read out from the shape of the pulse waveform indicated by the servo signals SBS3 and SBS4.

[0108] The data band identification unit 30B obtains the offset amount OS, for example, as follows: The third servo signal SBS3 and the fourth servo signal SBS4 have different phases, reflecting the difference in the predetermined interval. Specifically, when the magnetic tape MT is run in the forward direction, the fourth servo signal SBS4 is detected a time t1 corresponding to the predetermined interval later than the third servo signal SBS3. Therefore, the offset amount OS is the product of the time t1 corresponding to the predetermined interval and the running speed of the magnetic tape MT.

[0109] In the examples shown in Figures 10 and 11, the first identification unit 30B1 and the second identification unit 30B2 acquire the third servo signal SBS3 and the fourth servo signal SBS3, and the identification information ID and the offset amount OS are acquired from the third servo signal SBS3 and the fourth servo signal SBS4 using autocorrelation coefficients, but this is merely one example.

[0110] The first and second identifying units 30B1 and 30B2 may acquire the second and third servo signals SBS2 and SBS3, respectively. In this case, the data band identifying unit 30B acquires the identification information ID and the offset amount OS from the second and third servo signals SBS2 and SBS3 using autocorrelation coefficients.

[0111] Alternatively, the first and second servo signals SBS1 and SBS2 may be acquired by the first and second identifying units 30B1 and 30B2. In this case, the data band identifying unit 30B acquires the identification information ID and the offset amount OS from the first and second servo signals SBS1 and SBS2 using autocorrelation coefficients.

[0112] As an example, as shown in FIG. 12 , the data band identification unit 30B identifies a data band DB using a data band derivation table 30C. The data band derivation table 30C is a table that takes the identification result of the servo band SB indicated by the identification information ID and the offset amount OS as input values ​​and the number of the data band DB as output values. The data band derivation table 30C is pre-stored in the storage 32. The data band identification unit 30B acquires the data band derivation table 30C from the storage 32. The data band identification unit 30B derives data band identification information 30D from the data band derivation table 30C according to the identification information ID and the offset amount OS. The data band identification information 30D is information for identifying the data band DB. The data band identification unit 30B outputs the data band identification information 30D to the control unit 30A. For example, the data band identification information 30D is information indicating the number of the data band DB, but this is merely an example. The data band identification information 30D may be information indicating a symbol for identifying a data band DB. Note that, although the data band derivation table 30C is illustrated here, the technology of the present disclosure is not limited to this. For example, the data band DB number may be calculated by the data band identification unit 30B using an arithmetic expression in which a value indicating the identification result of the servo band SB indicated by the identification information ID and a value indicating the offset amount OS are independent variables, and the data band DB number is a dependent variable.

[0113] 13, the control unit 30A performs servo control based on data band identification information 30D acquired from the data band identification unit 30B. For example, the control unit 30A controls the moving mechanism 48 to move the magnetic head 28 to a position corresponding to the data band DB number indicated by the data band identification information 30D. By performing servo control, the multiple data read / write elements DRW are positioned over designated areas in the data band DB and perform magnetic processing on the designated areas in the data band DB. That is, the control unit 30A acquires a read signal from the magnetic element unit 42 (i.e., data read from the data band DB of the magnetic tape MT by the magnetic element unit 42) and supplies a recording signal to the magnetic element unit 42 to record data corresponding to the recording signal in the data band DB of the magnetic tape MT.

[0114] Recently, research has been conducted into techniques for reducing the effects of TDS (Transverse Dimensional Stability). TDS is influenced by factors such as temperature, humidity, the pressure at which the magnetic tape is wound around the reel, and deterioration over time. It is known that if no countermeasures are taken, TDS will increase, resulting in off-track (i.e., misalignment of the data read / write element DRW with respect to the track in the data band DB) when magnetic processing is performed on the data band DB.

[0115] The example shown in Figure 14 shows a state in which the width of the magnetic tape MT shrinks over time. In this case, off-track occurs. The width of the magnetic tape MT may also expand, and in this case, off-track occurs. That is, when the width of the magnetic tape MT shrinks or expands over time, the position of the servo read element SR relative to the servo pattern 58 deviates in the width direction WD from the predetermined position determined by design (e.g., the center position of each of the linear magnetized regions 60A1, 60A2, 60B1, and 60B2). When the position of the servo read element SR relative to the servo pattern 58 deviates in the width direction WD from the predetermined position determined by design, the accuracy of servo control decreases, and the track in the data band DB and the position of the data read / write element DRW are misaligned. As a result, magnetic processing is not performed on the originally intended track.

[0116] As a method for reducing the effects of TDS, the control unit 30A performs various controls based on the position detection results of the first position detection unit 30E1 (i.e., the results of position detection by the first position detection unit 30E1) and the position detection results of the second position detection unit 30E2 (i.e., the results of position detection by the second position detection unit 30E2). Here, the various controls refer to, for example, servo control, skew angle control, and / or tension control. Tension control refers to control of the tension applied to the magnetic tape MT (e.g., tension to reduce the effects of TDS).

[0117] 15, the control device 30 includes a control unit 30A and a position detection unit 30E. The position detection unit 30E includes a first position detection unit 30E1 and a second position detection unit 30E2. The position detection unit 30E acquires a servo signal resulting from the servo pattern 58 being read by the servo read element SR, and detects the position of the magnetic head 28 on the magnetic tape MT based on the acquired servo signal.

[0118] As an example, as shown in FIG. 16, the position detector 30E detects a servo signal, which is the result of the servo pattern 58 being read from the magnetic tape MT by the servo read element SR, using an autocorrelation coefficient.

[0119] The position of the servo read element SR relative to the servo band SB is detected, for example, as follows. The autocorrelation coefficient enables detection of the distance between the servo patterns 58A and 58B in the longitudinal direction LD. For example, when the servo read element SR is located above the servo pattern 58 (i.e., above the plane of FIG. 15 ), the distance between the linear magnetization regions 60A1 and 60A2 is narrow, and the distance between the linear magnetization regions 60B1 and 60B2 is also narrow. On the other hand, when the servo read element SR is located below the servo pattern 58 (i.e., below the plane of FIG. 15 ), the distance between the linear magnetization regions 60A1 and 60A2 is wide, and the distance between the linear magnetization regions 60B1 and 60B2 is also wide. In this way, the position detection unit 30E detects the position of the servo read element SR relative to the servo band SB using the interval between the linear magnetization regions 60A1 and 60A2 and the interval between the linear magnetization regions 60B1 and 60B2 detected according to the autocorrelation coefficient. The control unit 30A adjusts the position of the magnetic head 28 by operating the movement mechanism 48 based on the position detection result by the position detection unit 30E (i.e., the result of position detection by the position detection unit 30E). The control unit 30A also causes the magnetic element unit 42 to perform magnetic processing on the data band DB of the magnetic tape MT.

[0120] Furthermore, to reduce the effects of TDS, the control unit 30A calculates the servo band pitch from the position detection result of the position detection unit 30E, and performs tension control and skews the magnetic head 28 on the magnetic tape MT according to the calculated servo band pitch. Tension control is achieved by adjusting the rotation speed and rotation torque of the supply motor 36 and the take-up motor 40. Skew of the magnetic head 28 is achieved by operating the tilt mechanism 49. By skewing the magnetic head 28 on the magnetic tape MT, the position of the servo read element SR relative to the servo pattern 58 is maintained at a predetermined position determined by design.

[0121] As an example, as shown in FIG. 17 , the magnetic head 28 has a rotation axis RA. The rotation axis RA is provided at a position corresponding to the center of the magnetic element unit 42 included in the magnetic head 28 in a planar view. The magnetic head 28 is rotatably held by a tilting mechanism 49 via the rotation axis RA. A virtual line C3, which is a virtual center line, is provided in the magnetic head 28. The virtual line C3 passes through the rotation axis RA and extends in the longitudinal direction of the magnetic head 28 in a planar view (i.e., the direction in which multiple data read / write elements DRW are arranged). The magnetic head 28 is held by the tilting mechanism 49 so that the virtual line C3 is inclined toward the longitudinal direction of the magnetic tape MT with respect to a virtual line C4, which is a virtual line along the width direction WD. In the example shown in Figure 17, the magnetic head 28 is held by the tilting mechanism 49 in a position where the imaginary line C3 is tilted toward the supply reel 22 with respect to the imaginary line C4 (i.e., a position where the imaginary line C3 is tilted counterclockwise when viewed from the front side of the paper in Figure 17).

[0122] The tilt mechanism 49 receives power from a tilt actuator 49A (see FIG. 5 ) to rotate the magnetic head 28 about the rotation axis RA on the surface 31 of the magnetic tape MT. Under the control of the control device 30, the tilt mechanism 49 rotates the magnetic head 28 about the rotation axis RA on the surface 31 of the magnetic tape MT, thereby changing the direction and angle of tilt (i.e., azimuth) of the imaginary line C3 with respect to the imaginary line C4.

[0123] The direction and angle β of inclination of the virtual straight line C3 relative to the virtual straight line C4 are changed according to temperature, humidity, the pressure at which the magnetic tape MT is wound around the reel, deterioration over time, etc., or the expansion and contraction in the width direction WD of the magnetic tape MT due to these, thereby maintaining the position of the servo read element SR relative to the servo pattern 58 at a predetermined position determined by design.

[0124] Next, among the multiple steps included in the manufacturing process of the magnetic tape MT, an example of a servo pattern recording step of recording servo patterns 58 on the servo bands SB of the magnetic tape MT and a winding step of winding the magnetic tape MT will be described. In this embodiment, the servo pattern recording step is an example of a "manufacturing method of magnetic tape" according to the technology of the present disclosure.

[0125] 18, the servo pattern recording process uses a servo writer SW, which includes a supply reel SW1, a take-up reel SW2, a drive unit SW3, a pulse signal generator SW4, a control unit SW5, a plurality of guides SW6, a transport path SW7, a servo pattern recording head WH, and a verify head VH.

[0126] In this embodiment, the servo writer SW is an example of a "servo pattern recording device" according to the technology of the present disclosure. Also, in this embodiment, the servo pattern recording head WH is an example of a "servo pattern recording head" according to the technology of the present disclosure.

[0127] The control device SW5 controls the entire servo writer SW. In this embodiment, the control device SW5 is realized by an ASIC, but the technology of the present disclosure is not limited to this. For example, the control device SW5 may be realized by an FPGA and / or a PLC. The control device SW5 may also be realized by a computer including a CPU, flash memory (e.g., EEPROM and / or SSD), and RAM. The control device SW5 may also be realized by a combination of two or more of the ASIC, FPGA, PLC, and computer. In other words, the control device SW5 may be realized by a combination of hardware and software.

[0128] A pancake is set on the supply reel SW1. The pancake refers to a large diameter roll of magnetic tape MT, which is cut to the product width from a wide web before the servo pattern 58 is written, wound around a hub.

[0129] The drive unit SW3 has a motor (not shown) and gears (not shown) and is mechanically connected to the supply reel SW1 and the take-up reel SW2. When the magnetic tape MT is wound by the take-up reel SW2, the drive unit SW3 generates power in accordance with instructions from the control unit SW5 and transmits the generated power to the supply reel SW1 and the take-up reel SW2, thereby rotating the supply reel SW1 and the take-up reel SW2. That is, the supply reel SW1 receives power from the drive unit SW3 and rotates to feed the magnetic tape MT to the predetermined transport path SW7. The take-up reel SW2 receives power from the drive unit SW3 and rotates to wind the magnetic tape MT fed from the supply reel SW1. The rotation speeds and rotation torques of the supply reel SW1 and the take-up reel SW2 are adjusted according to the speed at which the magnetic tape MT is wound around the take-up reel SW2.

[0130] A plurality of guides SW6 and a servo pattern recording head WH are arranged on the transport path SW7. The servo pattern recording head WH is arranged on the surface 31 side of the magnetic tape MT between the plurality of guides SW6. The magnetic tape MT sent out from the supply reel SW1 to the transport path SW7 is guided by the plurality of guides SW6, passes over the servo pattern recording head WH, and is taken up by the take-up reel SW2.

[0131] The manufacturing process of the magnetic tape MT includes a number of steps in addition to the servo pattern recording step, including an inspection step and a winding step.

[0132] For example, the inspection process is a process of inspecting the servo bands SB formed on the surface 31 of the magnetic tape MT by the servo pattern recording head WH. Inspecting the servo bands SB refers to, for example, a process of determining whether the servo patterns 58 recorded on the servo bands SB are correct. Determining whether the servo patterns 58 are correct refers to, for example, determining whether the magnetization lines 60A1a, 60A2a, 60B1a, and 60B2a of the servo patterns 58A and 58B are recorded exactly and within the allowable error relative to predetermined locations on the surface 31 (i.e., verifying the servo patterns 58).

[0133] The inspection process is performed using the control device SW5 and the verify head VH. The verify head VH is located downstream of the servo pattern recording head WH in the transport direction of the magnetic tape MT. The verify head VH is also provided with multiple servo read elements (not shown), similar to the magnetic head 28, and the multiple servo read elements read multiple servo bands SB.

[0134] The verify head VH is connected to the control device SW5. The verify head VH is positioned directly opposite the servo bands SB when viewed from the surface 31 side of the magnetic tape MT (i.e., the back side of the verify head VH). The verify head VH reads the servo patterns 58 recorded on the servo bands SB and outputs the read results (hereinafter referred to as "servo pattern read results") to the control device SW5. The control device SW5 inspects the servo bands SB (e.g., determines whether the servo patterns 58 are correct) based on the servo pattern read results (e.g., servo signals) input from the verify head VH. For example, the control device SW5 operates as the position detection unit 30E shown in FIG. 15 to obtain position detection results from the servo pattern read results and inspects the servo bands SB by using the position detection results to determine whether the servo patterns 58 are correct.

[0135] The control device SW5 outputs information indicating the results of inspecting the servo band SB (e.g., the results of determining whether the servo pattern 58 is correct or not) to a predetermined output destination (e.g., storage 32 (see Figure 3), UI device 34 (see Figure 3), and / or external device 37 (see Figure 3), etc.).

[0136] For example, after the inspection process is completed, the winding process is carried out next. The winding process is a process of winding the magnetic tape MT around the supply reel 22 (see FIGS. 2 to 4) housed in the magnetic tape cartridge 12 (see FIGS. 1 to 4)) used for each of the multiple magnetic tape cartridges 12 (see FIGS. 1 to 4). In the winding process, a winding motor M is used. The winding motor M is mechanically connected to the supply reel 22 via a gear or the like. Under the control of a control device (not shown), the winding motor M applies a rotational force to the supply reel 22 to rotate the supply reel 22. The magnetic tape MT wound around the take-up reel SW2 is wound onto the supply reel 22 by the rotation of the supply reel 22. In the winding process, a cutting device (not shown) is used. When the required amount of magnetic tape MT is wound onto each of the plurality of supply reels 22, the magnetic tape MT fed from the take-up reel SW2 to the supply reel 22 is cut by a cutting device.

[0137] The pulse signal generator SW4 generates a pulse current under the control of the control device SW5 and supplies the generated pulse current to the servo pattern recording head WH. While the magnetic tape MT is traveling at a constant speed on the transport path SW7, the servo pattern recording head WH records the servo pattern 58 on the servo band SB in accordance with the pulse current supplied from the pulse signal generator SW4.

[0138] Figure 19 shows an example of the configuration of the servo pattern recording head WH when observed from the surface 31 side (i.e., the back side of the servo pattern recording head WH) of the magnetic tape MT running on the transport path SW7 (see Figure 18), and an example of the configuration of the pulse signal generator SW4.

[0139] As an example, as shown in Figure 19, the servo pattern recording head WH has a base body WH1 and multiple head cores WH2. The base body WH1 is formed in a rectangular parallelepiped shape and is arranged to cross the surface 31 of the magnetic tape MT running on the transport path SW7 in the width direction WD. The surface WH1A of the base body WH1 is rectangular with a long side WH1Aa and a short side WH1Ab. In this embodiment, the multiple head cores WH2 are an example of the "multiple head cores" according to the technology of the present disclosure.

[0140] The surface WH1A has a sliding surface WH1Ax. The sliding surface WH1Ax is a portion of the surface WH1A that overlaps with the surface 31 of the magnetic tape MT when the substrate WH1 diagonally crosses the surface 31 of the magnetic tape MT in the width direction WD (e.g., the dotted hatched area shown in FIG. 19 ), and slides against the running magnetic tape MT. The width of the sliding surface WH1Ax (i.e., the length of the short side WH1Ab) shown in FIG. 19 is merely an example, and the width of the sliding surface WH1Ax may be several times wider than the example shown in FIG. 19 .

[0141] A plurality of head cores WH2 are assembled in the base body WH1 along the long side WH1Aa. The head cores WH2 are magnetically separated from one another. For example, a non-magnetic layer (e.g., a ceramic layer) is formed between the head cores WH2. This prevents the magnetic fields generated in adjacent head cores WH2 from interfering with each other.

[0142] A gap pattern G is formed on the head core WH2. The gap pattern G is formed on the surface WH1A (i.e., the surface of the substrate WH1 facing the surface 31 of the magnetic tape MT). The gap pattern G is composed of a pair of non-parallel linear regions. The pair of non-parallel linear regions refers to, for example, a linear region having the same geometric characteristics as the magnetization line 60A1a located at the most upstream side in the forward direction among the five magnetization lines 60A1a included in the linear magnetization region 60A1 shown in FIG. 7, and a linear region having the same geometric characteristics as the magnetization line 60A2a located at the most upstream side in the forward direction among the five magnetization lines 60A2a included in the linear magnetization region 60A2 shown in FIG.

[0143] A plurality of gap patterns G are formed on the surface WH1A along the direction WD1. On the surface WH1A, the distance in the direction WD1 between adjacent gap patterns G in the direction WD1 corresponds to the distance in the width direction WD between the servo bands SB of the magnetic tape MT (i.e., the servo band pitch).

[0144] A coil (not shown) is wound around the head core WH2, and pulse currents are supplied to the coils, including a pulse current for the servo pattern 58A and a pulse current for the servo pattern 58B.

[0145] When a pulse current for servo pattern 58A is supplied to the coil of head core WH2 with gap pattern G facing directly to magnetic tape MT running on transport path SW7, a magnetic field is applied from gap pattern G to magnetic tape MT in accordance with the pulse current. As a result, servo pattern 58A is recorded on magnetic tape MT. Also, when a pulse current for servo pattern 58B is supplied to the coil of head core WH2 with gap pattern G facing directly to magnetic tape MT running on transport path SW7, a magnetic field is applied from gap pattern G to magnetic tape MT. As a result, servo pattern 58B is recorded on magnetic tape MT.

[0146] Here, the information indicated by the pulse current supplied to the head core WH2A includes identification information ID. As described above, the pulse current corresponding to each servo pattern 58 (i.e., the servo pattern 58 for each frame 56 (see FIG. 7)) is modulated. By modulating the pulse signal, the identification information ID is embedded in the pulse current.

[0147] In the example shown in Figure 19, head cores WH2A and WH2B are shown as an example of a plurality of head cores WH2, and gap patterns G1, G2, G3, and G4 are shown as an example of a plurality of gap patterns G. Gap pattern G1 and gap pattern G2 are formed in head core WH2A. Gap pattern G3 and gap pattern G4 are formed in head core WH2B. In this embodiment, gap patterns G1 to G4 are an example of "a plurality of gap patterns" according to the technology of the present disclosure.

[0148] Gap patterns G1 to G4 each have the same geometric characteristics. In this embodiment, for example, gap pattern G1 is used to record servo pattern 58 (see FIG. 9) for servo band SB4 (see FIG. 9). Gap pattern G2 is used to record servo pattern 58 (see FIG. 9) for servo band SB3 (see FIG. 9). Gap pattern G3 is used to record servo pattern 58 (see FIG. 9) for servo band SB2 (see FIG. 9). Gap pattern G4 is used to record servo pattern 58 (see FIG. 9) for servo band SB1 (see FIG. 9).

[0149] Gap pattern G1 is a pair of linear regions consisting of linear regions G1A and G1B. Gap pattern G2 is a pair of linear regions consisting of linear regions G2A and G2B. Gap pattern G3 is a pair of linear regions consisting of linear regions G3A and G3B. Gap pattern G4 is a pair of linear regions consisting of linear regions G4A and G4B.

[0150] The pulse signal generator SW4 has a first pulse signal generator SW4A and a second pulse signal generator SW4B. The first pulse signal generator SW4A is connected to the head core WH2A. The second pulse signal generator SW4B is connected to the head core WH2B. In this embodiment, the first pulse signal generator SW4A and the second pulse signal generator SW4B are examples of a "pulse signal generator" according to the technology of the present disclosure.

[0151] When the gap pattern G1 is used for the servo band SB4 (see Figure 9), when the first pulse signal generator SW4A supplies a pulse current to the head core WH2A, a magnetic field is applied from the gap pattern G1 to the magnetic tape MT in accordance with the pulse current, and the servo pattern 58 (see Figure 9) is recorded on the magnetic tape MT.

[0152] For example, when a pulse current for the servo pattern 58A is supplied to the head core WH2A with the gap pattern G1 facing the magnetic tape MT running on the transport path SW7, the servo pattern 58A (see FIG. 9) is recorded on the magnetic tape MT. That is, a linear magnetized region 60A1 (see FIG. 9) is recorded on the magnetic tape MT by the linear region G1A, and a linear magnetized region 60A2 (see FIG. 9) is recorded on the magnetic tape MT by the linear region G1B.

[0153] Furthermore, for example, when a pulse current for the servo pattern 58B is supplied to the head core WH2A with the gap pattern G1 facing the magnetic tape MT running on the transport path SW7, the servo pattern 58B (see FIG. 9) is recorded on the magnetic tape MT. That is, a linear magnetization region 60B1 (see FIG. 9) is recorded on the magnetic tape MT by the linear region G1A, and a linear magnetization region 60B2 (see FIG. 9) is recorded on the magnetic tape MT by the linear region G1B.

[0154] When the gap pattern G2 is used for the servo band SB3 (see Figure 9), when the first pulse signal generator SW4A supplies a pulse current to the head core WH2A, a magnetic field is applied from the gap pattern G2 to the magnetic tape MT in accordance with the pulse current, and the servo pattern 58 is recorded on the magnetic tape MT.

[0155] For example, when a pulse current for the servo pattern 58A is supplied to the head core WH2A with the gap pattern G2 facing the magnetic tape MT running on the transport path SW7, the servo pattern 58A (see FIG. 9) is recorded on the magnetic tape MT. That is, a linear magnetized region 60A1 is recorded on the magnetic tape MT by the linear region G2A, and a linear magnetized region 60A2 is recorded on the magnetic tape MT by the linear region G2B.

[0156] Furthermore, for example, when a pulse current for the servo pattern 58B is supplied to the head core WH2A with the gap pattern G2 facing the magnetic tape MT running on the transport path SW7, the servo pattern 58B is recorded on the magnetic tape MT. That is, a linear magnetization region 60B1 is recorded on the magnetic tape MT by the linear region G2A, and a linear magnetization region 60B2 is recorded on the magnetic tape MT by the linear region G2B.

[0157] When the gap pattern G3 is used for the servo band SB2 (see Figure 9), when the second pulse signal generator SW4B supplies a pulse current to the head core WH2B, a magnetic field is applied from the gap pattern G3 to the magnetic tape MT in accordance with the pulse current, and the servo pattern 58 is recorded on the magnetic tape MT.

[0158] For example, when a pulse current for the servo pattern 58A is supplied to the head core WH2B with the gap pattern G3 facing the magnetic tape MT running on the transport path SW7, the servo pattern 58A is recorded on the magnetic tape MT. That is, a linear magnetization region 60A1 is recorded on the magnetic tape MT by the linear region G3A, and a linear magnetization region 60A2 is recorded on the magnetic tape MT by the linear region G3B.

[0159] Furthermore, for example, when a pulse current for the servo pattern 58B is supplied to the head core WH2B with the gap pattern G3 facing the magnetic tape MT running on the transport path SW7, the servo pattern 58B is recorded on the magnetic tape MT. That is, a linear magnetization region 60B1 is recorded on the magnetic tape MT by the linear region G3A, and a linear magnetization region 60B2 is recorded on the magnetic tape MT by the linear region G3B.

[0160] When the gap pattern G4 is used for the servo band SB1 (see Figure 9), when the second pulse signal generator SW4B supplies a pulse current to the head core WH2B, a magnetic field is applied from the gap pattern G4 to the magnetic tape MT in accordance with the pulse current, and the magnetic tape MT is recorded.

[0161] For example, when a pulse current for the servo pattern 58A is supplied to the head core WH2B with the gap pattern G4 facing the magnetic tape MT running on the transport path SW7, the servo pattern 58A is recorded on the magnetic tape MT. That is, a linear magnetization region 60A1 is recorded on the magnetic tape MT by the linear region G4A, and a linear magnetization region 60A2 is recorded on the magnetic tape MT by the linear region G4B.

[0162] Furthermore, for example, when a pulse current for the servo pattern 58B is supplied to the head core WH2B with the gap pattern G4 facing the magnetic tape MT running on the transport path SW7, the servo pattern 58B is recorded on the magnetic tape MT. That is, a linear magnetization region 60B1 is recorded on the magnetic tape MT by the linear region G4A, and a linear magnetization region 60B2 is recorded on the magnetic tape MT by the linear region G4B.

[0163] 20, in the gap pattern G1, the linear regions G1A and G1B are inclined in opposite directions with respect to a virtual line C2, which is a virtual line extending along the width direction WD. The linear regions G1A and G1B are inclined in line symmetry with respect to the virtual line C2. More specifically, the linear regions G1A and G1B are non-parallel to each other and are inclined at a predetermined angle (e.g., 5 degrees) in opposite directions in the longitudinal direction LD of the magnetic tape MT with the virtual line C2 as the axis of symmetry.

[0164] In the gap pattern G2, the linear regions G2A and G2B are inclined in opposite directions with respect to a virtual line C2, which is a virtual line extending along the width direction WD. The linear regions G2A and G2B are inclined in line symmetry with respect to the virtual line C2. More specifically, the linear regions G2A and G2B are non-parallel to each other and are inclined at a predetermined angle (e.g., 5 degrees) in opposite directions in the longitudinal direction LD of the magnetic tape MT with the virtual line C2 as the axis of symmetry.

[0165] In the gap pattern G3, the linear regions G3A and G3B are inclined in opposite directions with respect to a virtual line C2, which is a virtual line extending along the width direction WD. The linear regions G3A and G3B are inclined in line symmetry with respect to the virtual line C2. More specifically, the linear regions G3A and G3B are non-parallel to each other and are inclined at a predetermined angle (e.g., 5 degrees) in opposite directions in the longitudinal direction LD of the magnetic tape MT with the virtual line C2 as the axis of symmetry.

[0166] In the gap pattern G4, the linear regions G4A and G4B are inclined in opposite directions with respect to a virtual line C2, which is a virtual line extending along the width direction WD. The linear regions G4A and G4B are inclined in line symmetry with respect to the virtual line C2. More specifically, the linear regions G4A and G4B are non-parallel to each other and are inclined at a predetermined angle (e.g., 5 degrees) in opposite directions in the longitudinal direction LD of the magnetic tape MT with the virtual line C2 as the axis of symmetry.

[0167] The gap patterns G1 and G2 are offset by the above-mentioned predetermined interval between adjacent gap patterns G along the direction WD1 in a direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

[0168] The gap patterns G3 and G4 are offset by the above-mentioned predetermined interval between adjacent gap patterns G along the direction WD1 in the direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

[0169] The arrangement of the gap pattern G in the head core WH2A (i.e., the positional relationship between the gap pattern G1 and the gap pattern G2) is the same as the arrangement of the gap pattern G in the head core WH2B (i.e., the positional relationship between the gap pattern G3 and the gap pattern G4). That is, the gap pattern G is arranged in common between the head cores WH2A and WH2B.

[0170] The pulse currents used in gap patterns G1 and G2 (i.e., the pulse currents supplied from the first pulse signal generator SW4A to the head core WH2A as shown in FIG. 19) are in-phase signals. Also, the pulse currents used in gap patterns G3 and G4 (i.e., the pulse currents supplied from the second pulse signal generator SW4B to the head core WH2B as shown in FIG. 19) are in-phase currents. That is, the pulse currents used in units of head core WH2 are in-phase currents. In this embodiment, in-phase currents refer to currents that are in the same phase, as well as currents that are in the same phase but include an error that is generally acceptable in the technical field to which the technology of the present disclosure pertains and that does not contradict the spirit of the technology of the present disclosure.

[0171] In the servo pattern recording process, the magnetic tape MT runs at a constant speed on the transport path SW7 with the position of gap pattern G1 corresponding to the position of servo band SB4 and the position of gap pattern G2 corresponding to the position of servo band SB3. The magnetic tape MT also runs at a constant speed on the transport path SW7 with the position of gap pattern G3 corresponding to the position of servo band SB2 and the position of gap pattern G4 corresponding to the position of servo band SB1. In this state, pulse currents for servo pattern 58A and servo pattern 58B are alternately supplied to head core WH2A and head core WH2B.

[0172] When a pulse current for servo pattern 58A is supplied to head core WH2A in phase, servo pattern 58A is recorded on servo bands SB4 and SB3 with a predetermined interval offset in the longitudinal direction LD. Also, when a pulse current for servo pattern 58B is supplied to head core WH2A in phase, servo pattern 58B is recorded on servo bands SB4 and SB3 with a predetermined interval offset in the longitudinal direction LD.

[0173] When a pulse current for servo pattern 58B is supplied to head core WH2B in phase, servo pattern 58A is recorded on servo band SB2 and servo band SB1 with a predetermined interval offset in the longitudinal direction LD. Also, when a pulse current for servo pattern 58B is supplied to head core WH2B in phase, servo pattern 58B is recorded on servo band SB2 and servo band SB1 with a predetermined interval offset in the longitudinal direction LD.

[0174] Next, the operation of the magnetic tape system 10 will be described.

[0175] The magnetic tape cartridge 12 contains the magnetic tape MT shown in Fig. 9 (see Figs. 9 and 11). The magnetic tape cartridge 12 is loaded into the magnetic tape drive 14. In the magnetic tape drive 14, when magnetic processing is performed on the magnetic tape MT by the magnetic element unit 42 (see Figs. 3 and 15), the magnetic tape MT is pulled out of the magnetic tape cartridge 12, and the servo read element SR of the magnetic head 28 reads the servo patterns 58 in the servo bands SB.

[0176] Here, a plurality of servo band sets SBP1 and SBP2 are formed on the magnetic tape MT in the width direction WD. Furthermore, on the magnetic tape MT, a plurality of corresponding servo patterns 58 between the servo bands SB are offset by a predetermined interval in the longitudinal direction LD of the magnetic tape MT between adjacent servo bands SB in the width direction WD. Furthermore, the servo patterns 58 have set identification information PID recorded therein for identifying the corresponding servo band sets SBP1 and SBP2. This allows the servo bands SB to be identified based on the offset of the predetermined interval formed in the servo patterns 58 between adjacent servo bands SB and the set identification information PID. That is, the combination of the set identification information PID and the offset of the predetermined interval between the servo patterns 58 uniquely identifies the servo band set SBP. Identifying the servo band set SBP allows the servo band SB to be identified. Being able to identify the servo band SB also means being able to identify the data band DB present between adjacent servo bands SB. Therefore, this configuration can contribute to identifying the data band DB.

[0177] Furthermore, information for identifying the sets of servo patterns SBP1 and SBP2 is recorded by a common pulse current. By specifying the set of servo bands SBP, the servo band SB can be identified. Being able to identify the servo band SB also means being able to identify the data band DB present between adjacent servo bands SB. Therefore, this configuration can contribute to identifying the data band DB.

[0178] Next, the operation of the servo writer SW will be described.

[0179] In the servo writer SW according to this embodiment, when the servo pattern recording head WH is to record the servo pattern 58 on the magnetic tape MT, the magnetic tape MT is sent out onto the transport path SW7 and run at a constant speed. At this time, the position of the gap pattern G1 is made to correspond to the position of the servo band SB4, and the position of the gap pattern G2 is made to correspond to the position of the servo band SB3. Furthermore, the position of the gap pattern G3 is made to correspond to the position of the servo band SB2, and the position of the gap pattern G4 is made to correspond to the position of the servo band SB1. In this state, the magnetic tape MT is run. Then, pulse signals for the servo pattern 58A and pulse signals for the servo pattern 58B are alternately supplied to the head cores WH2A and WH2B of the servo pattern recording head WH.

[0180] A plurality of gap patterns G are formed on each of the magnetically separated head cores WH2. A plurality of servo patterns 58 are recorded on the magnetic tape MT with the plurality of gap patterns G in the longitudinal direction LD of the magnetic tape MT, thereby forming a plurality of servo bands SB along the width direction WD of the magnetic tape MT. The plurality of gap patterns G are offset by a predetermined interval between adjacent gap patterns G along the direction corresponding to the width direction WD of the magnetic tape MT. This allows the gap pattern G to be identified in each of the separated head cores WH2 based on the offset of the predetermined interval formed between adjacent gap patterns G. Being able to identify the gap pattern G in each head core WH2 means that the plurality of servo bands SB corresponding to the head core WH2 can also be identified on a head core WH2 basis. This also means that the data bands DB present between adjacent servo bands SB can be identified on a head core WH2 basis. Therefore, this configuration contributes to identifying the data bands DB. Furthermore, since the pulse signal is supplied to each separate head core WH2, the current value representing the pulse signal can be reduced. For example, compared to when a current is supplied by changing the pulse signal for each gap pattern G, the current value supplied to the head core WH2 can be reduced. As a result, heat generation in the servo pattern recording head WH is suppressed. Therefore, with this configuration, the thermal effects (e.g., thermal contraction of the magnetic tape MT due to heat generation in the servo pattern recording head WH) when recording the servo patterns 58 on the magnetic tape MT are reduced.

[0181] This configuration also reduces the occurrence of crosstalk. That is, since the multiple head cores WH2 are magnetically separated, the magnetic field formed by the pulse current supplied to the head core WH2 is prevented from overlapping with the adjacent head core WH2. This reduces the occurrence of crosstalk.

[0182] Furthermore, in the servo pattern recording head WH according to this embodiment, the information indicated by the pulse current includes identification information ID. Servo bands SB are formed by the servo pattern recording head WH recording a plurality of servo patterns 58 in the longitudinal direction LD of the magnetic tape MT in accordance with the pulse current. This makes it possible to identify the servo bands SB in units of head core WH2. Therefore, it is possible to identify the data bands DB present between adjacent servo bands SB in the width direction of the magnetic tape MT.

[0183] In the servo pattern recording head WH according to this embodiment, the identification information ID is common to each head core WH2. Therefore, according to this configuration, the servo patterns 58 recorded by the servo pattern recording head WH having multiple head cores WH2 can be identified on a head core WH2 basis.

[0184] Furthermore, in the servo pattern recording head WH according to this embodiment, the plurality of gap patterns G are arranged in common among the head cores WH2. Therefore, this configuration can simplify the configuration of the servo pattern recording head WH having the plurality of head cores WH2.

[0185] In the servo pattern recording head WH according to this embodiment, the pulse currents used for each head core WH2 are in phase. Therefore, this configuration simplifies the generation of the pulse currents supplied to each magnetically separated head core WH2.

[0186] Furthermore, in the servo writer SW according to this embodiment, pulse signal generators SW4A and SW4B are provided for each head core WH2A and WH2B. This allows a pulse current to be supplied to each separate head core WH2, thereby reducing the pulse current value. For example, compared to a case where a pulse signal generator SW4 is provided for each gap pattern G and current is supplied, the current value supplied to the head core WH2 can be reduced. As a result, heat generation in the servo pattern recording head WH is suppressed. Therefore, this configuration reduces thermal effects (e.g., thermal contraction of the magnetic tape MT due to heat generation in the servo pattern recording head WH) when recording the servo patterns 58 on the magnetic tape MT. Furthermore, compared to a case where a pulse signal generator SW4 is provided for each servo pattern 58, for example, the number of pulse signal generators SW4 can be reduced, thereby reducing capital investment in the servo writer SW.

[0187] In the above embodiment, an example was described in which two gap patterns G are formed on the surface WH1A of the head core WH2 in the servo pattern recording head WH. However, the technology of the present disclosure is not limited to this. In this first modification, three gap patterns G are formed on the surface WH1A of the head core WH2.

[0188] 21, the servo pattern recording head WH has a base body WH1 and multiple head cores WH2. The base body WH1 has multiple head cores WH2 built in along the direction of the long side WH1Aa. The multiple head cores WH2 are magnetically separated.

[0189] The head core WH2 is formed with a gap pattern G. The gap pattern G is formed on the surface WH1A (that is, the surface of the substrate WH1 that faces the surface 31 of the magnetic tape MT).

[0190] 21 shows head cores WH2A and WH2B as an example of a plurality of head cores WH2, and gap patterns G11, G12, G13, G14, G15, and G16 as an example of a plurality of gap patterns G. Gap patterns G11, G12, and G13 are formed in head core WH2A. Gap patterns G14, G15, and G16 are formed in head core WH2B. In this modification, gap patterns G11 to G16 are an example of "a plurality of gap patterns" according to the technology of the present disclosure.

[0191] Gap patterns G11 to G16 each have the same geometric characteristics. In this modification, for example, gap pattern G11 is used to record servo pattern 58 (see FIG. 22) for servo band SB6 (see FIG. 22). Gap pattern G12 is used to record servo pattern 58 (see FIG. 22) for servo band SB5 (see FIG. 22). Gap pattern G13 is used to record servo pattern 58 (see FIG. 22) for servo band SB4 (see FIG. 22). Gap pattern G14 is used to record servo pattern 58 (see FIG. 22) for servo band SB3 (see FIG. 22). Gap pattern G15 is used to record servo pattern 58 (see FIG. 22) for servo band SB2 (see FIG. 22). Gap pattern G16 is used to record servo pattern 58 (see FIG. 22) for servo band SB1 (see FIG. 22).

[0192] Gap pattern G11 is a pair of linear regions consisting of linear regions G11A and G11B. Gap pattern G12 is a pair of linear regions consisting of linear regions G12A and G12B. Gap pattern G13 is a pair of linear regions consisting of linear regions G13A and G13B. Gap pattern G14 is a pair of linear regions consisting of linear regions G14A and G14B. Gap pattern G15 is a pair of linear regions consisting of linear regions G15A and G15B. Gap pattern G16 is a pair of linear regions consisting of linear regions G16A and G16B.

[0193] The pulse signal generator SW4 has a first pulse signal generator SW4A and a second pulse signal generator SW4B. The first pulse signal generator SW4A is connected to the head core WH2A. The second pulse signal generator SW4B is connected to the head core WH2B.

[0194] When the gap pattern G11 is used for the servo band SB6 (see Figure 22), when the first pulse signal generator SW4A supplies a pulse current to the head core WH2A, a magnetic field is applied from the gap pattern G11 to the magnetic tape MT in accordance with the pulse current, and the servo pattern 58 (see Figure 22) is recorded on the magnetic tape MT.

[0195] Similarly, the gap patterns G12 and G13 are supplied with a pulse current from the first pulse signal generator SW4A, and a servo pattern 58 is recorded in the servo bands SB5 and SB4.

[0196] When the gap pattern G14 is used for the servo band SB3 (see Figure 22), when the second pulse signal generator SW4B supplies a pulse current to the head core WH2B, a magnetic field is applied from the gap pattern G14 to the magnetic tape MT in accordance with the pulse current, and the servo pattern 58 (see Figure 22) is recorded on the magnetic tape MT.

[0197] Similarly, the gap patterns G15 and G16 are supplied with a pulse current from the second pulse signal generator SW4B, whereby a servo pattern 58 is recorded on the magnetic tape MT.

[0198] The gap patterns G11 and G12 are offset at the above-mentioned predetermined interval between adjacent gap patterns G along the direction WD1 in a direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

[0199] Furthermore, the gap patterns G12 and G13 are offset at the above-mentioned predetermined interval between adjacent gap patterns G along the direction WD1 in the direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

[0200] Here, the direction of the shift of the predetermined interval between gap pattern G13 and gap pattern G12 is opposite to the direction of the shift of the predetermined interval between gap pattern G12 and gap pattern G11. In the example shown in Fig. 21, gap pattern G12 is shifted to the right relative to gap pattern G11 as viewed from the front side of the paper. On the other hand, gap pattern G13 is shifted to the left relative to gap pattern G12 as viewed from the front side of the paper.

[0201] Furthermore, the gap patterns G11 and G13 are arranged at the same position in the direction LD1 corresponding to the longitudinal direction LD. Furthermore, the gap patterns G13 and G14 are arranged at the same position in the direction LD1 corresponding to the longitudinal direction LD.

[0202] The gap patterns G14 and G15 are offset at the above-mentioned predetermined interval between adjacent gap patterns G along the direction WD1 in the direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

[0203] Furthermore, the gap patterns G15 and G16 are offset at the above-mentioned predetermined interval between adjacent gap patterns G along the direction WD1 in the direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

[0204] Here, the direction of the shift of the predetermined distance between gap pattern G16 and gap pattern G15 is opposite to the direction of the shift of the predetermined distance between gap pattern G15 and gap pattern G14. In the example shown in Fig. 21, gap pattern G15 is shifted to the right relative to gap pattern G14 as viewed from the front side of the paper. On the other hand, gap pattern G16 is shifted to the left relative to gap pattern G15 as viewed from the front side of the paper.

[0205] Furthermore, the gap patterns G14 and G16 are arranged at the same position in the direction LD1 corresponding to the longitudinal direction LD.

[0206] The arrangement of the gap pattern G in the head core WH2A and the arrangement of the gap pattern G in the head core WH2B are the same, that is, the gap pattern G is arranged in common between the head cores WH2A and WH2B.

[0207] The pulse currents used in gap patterns G11 to G13 (i.e., as shown in FIG. 21, the pulse currents supplied from the first pulse signal generator SW4A to the head core WH2A) are in-phase signals. Also, the pulse currents used in gap patterns G14 to G16 (i.e., as shown in FIG. 21, the pulse currents supplied from the second pulse signal generator SW4B to the head core WH2B) are in-phase currents. In other words, the pulse currents used in units of head core WH2 are in-phase currents.

[0208] 22, servo bands SB1, SB2, SB3, SB4, SB5, and SB6 and data bands DB1, DB2, DB3, DB4, and DB5 are formed on the surface 31 of the magnetic tape MT. The servo bands SB1 to SB6 are examples of "servo bands" according to the technology of the present disclosure. Note that, for convenience of explanation, the servo bands SB1 to SB6 will be referred to as servo bands SB, and the data bands DB1 to DB5 will be referred to as data bands DB, unless a distinction is particularly needed.

[0209] Data band DB1 is arranged between servo band SB1 and servo band SB2, and data band DB2 is arranged between servo band SB2 and servo band SB3. Data band DB3 is arranged between servo band SB3 and servo band SB4. Data band DB4 is arranged between servo band SB4 and servo band SB5. Data band DB5 is arranged between servo band SB5 and servo band SB6. In other words, servo bands SB and data bands DB are arranged alternately along the width direction WD.

[0210] Here, the servo bands SB4, SB5, and SB6 form one servo band set SBP1. In other words, the servo band set SBP1 includes the servo bands SB4, SB5, and SB6.

[0211] Furthermore, the servo bands SB1, SB2, and SB3 form another servo band set SBP2, in other words, the servo band set SBP2 includes the servo bands SB1, SB2, and SB3.

[0212] As described above, in the magnetic tape MT according to the first modification, the plurality of servo patterns 58 corresponding to each other between the servo bands SB are shifted at a predetermined interval in the longitudinal direction LD of the magnetic tape MT between the servo bands SB adjacent in the width direction WD. Furthermore, the servo patterns 58 have recorded therein set identification information PID for identifying the corresponding sets of servo bands SBP1 and SBP2. Furthermore, the set of servo bands SBP includes three servo bands SB.

[0213] As a result, even if the servo band set SBP includes three servo bands SB, the servo bands SB can be identified based on the predetermined interval difference formed in the servo pattern 58 between adjacent servo bands SB and the information for identifying the servo band sets SBP1 and SBP2. That is, the servo bands SB of the servo band sets SBP1 and SBP2 are identified by combining the set identification information PID and the predetermined interval difference between the servo patterns 58. Being able to identify the servo bands SB also means being able to identify the data bands DB present between adjacent servo bands SB. Therefore, this configuration can contribute to identifying the data bands DB even if the servo band set SBP includes three servo bands SB.

[0214] Furthermore, the set identification information PID is recorded using a common pulse current. This allows a common circuit for supplying the pulse current, thereby reducing the pulse current value. For example, compared to when a separate circuit is provided for each servo pattern 58 to supply current, the current value when recording the servo patterns 58 can be reduced. Therefore, this configuration reduces the thermal effects (e.g., thermal contraction of the magnetic tape MT due to heat generated by the servo pattern recording head WH) and the occurrence of crosstalk when recording the servo patterns 58 on the magnetic tape MT.

[0215] For example, consider a case where only the set identification information PID is used to identify the servo bands SB. In this case, the number of servo bands SB included in the servo band set SBP is limited to two. This is because, if the servo band set SBP includes three servo bands SB, the servo bands SB within the servo band set SBP cannot be identified using only the set identification information PID. Therefore, when identifying the servo bands SB using only the set identification information PID, the servo band set SBP can only include two servo bands SB. On the other hand, in the magnetic tape MT according to the first modified example, the servo bands SB are identified using the set identification information PID and the deviation of the predetermined intervals of the servo patterns 58. Therefore, even if the servo band set SBP includes three servo bands SB, the servo bands SB can be identified. That is, even if common set identification information PID is recorded in the servo patterns 58 in the set of servo bands SBP, the servo bands SB in the set of servo bands SBP can be identified by the deviation of the predetermined intervals of the servo patterns 58.

[0216] In the first modification, three gap patterns G are formed on the surface WH1A of the head core WH2 in the servo pattern recording head WH. However, the technology of the present disclosure is not limited to this. In the second modification, five gap patterns G are formed on the surface WH1A of the head core WH2.

[0217] As an example, as shown in FIG. 23 , a gap pattern G is formed in the head core WH2. In the example shown in FIG. 23 , head cores WH2A and WH2B are shown as examples of the multiple head cores WH2, and gap patterns G21, G22, G23, G24, G25, and G26 are shown as examples of the multiple gap patterns G. Gap patterns G21 to G25 are formed in the head core WH2A. Gap pattern G26 is formed in the head core WH2B. Although not shown, four gap patterns G having the same geometric characteristics and arrangement as each of gap patterns G22 to G25 are formed in the head core WH2B. In this modification, gap patterns G21 to G26 are an example of "multiple gap patterns" according to the technology of the present disclosure.

[0218] The pulse signal generator SW4 has a first pulse signal generator SW4A and a second pulse signal generator SW4B. The first pulse signal generator SW4A is connected to the head core WH2A. The second pulse signal generator SW4B is connected to the head core WH2B.

[0219] When the gap pattern G21 is used for the servo band SB6 (see Figure 24), when the first pulse signal generator SW4A supplies a pulse current to the head core WH2A, a magnetic field is applied from the gap pattern G21 to the magnetic tape MT in accordance with the pulse current, and the servo pattern 58 (see Figure 24) is recorded on the magnetic tape MT.

[0220] Similarly, the gap patterns G22 to G25 are supplied with a pulse current from the first pulse signal generator SW4A, and a servo pattern 58 is recorded on the magnetic tape MT.

[0221] The gap patterns G21 and G22 are offset at the above-mentioned predetermined interval between adjacent gap patterns G along the direction WD1 in a direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

[0222] Furthermore, the gap patterns G22 and G23 are offset at the above-mentioned predetermined interval between adjacent gap patterns G along the direction WD1 in the direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

[0223] Here, the direction of the shift of the predetermined interval of gap pattern G23 relative to gap pattern G22 is opposite to the direction of the shift of the predetermined interval of gap pattern G22 relative to gap pattern G21. In the example shown in Fig. 23, gap pattern G22 is shifted to the right relative to gap pattern G21 as viewed from the front side of the paper. On the other hand, gap pattern G23 is shifted to the left relative to gap pattern G22 as viewed from the front side of the paper.

[0224] Furthermore, the gap patterns G21 and G23 are arranged at the same position in a direction LD1 corresponding to the longitudinal direction LD.

[0225] Gap patterns G23 and G24 are offset between adjacent gap patterns G along direction WD1 in a direction LD1 corresponding to the longitudinal direction LD (e.g., the same direction as the longitudinal direction LD) at an interval different from the above-mentioned default interval (e.g., an interval twice the default interval).

[0226] Gap patterns G24 and G25 are offset between adjacent gap patterns G along direction WD1 in a direction LD1 corresponding to the longitudinal direction LD (e.g., the same direction as the longitudinal direction LD) at an interval different from the above-mentioned default interval (e.g., an interval twice the default interval).

[0227] Here, the direction of the shift of the predetermined distance between gap pattern G25 and gap pattern G24 is opposite to the direction of the shift of the predetermined distance between gap pattern G24 and gap pattern G23. In the example shown in Fig. 23, gap pattern G24 is shifted to the right relative to gap pattern G23 when viewed from the front side of the paper. On the other hand, gap pattern G25 is shifted to the left relative to gap pattern G24 when viewed from the front side of the paper.

[0228] Furthermore, the gap patterns G25 and G26 are arranged at the same position in the direction LD1 corresponding to the longitudinal direction LD.

[0229] The arrangement of the gap pattern G in the head core WH2A and the arrangement of the gap pattern G in the head core WH2B are the same, that is, the gap pattern G is arranged in common between the head cores WH2A and WH2B.

[0230] The pulse currents used in gap patterns G21 to G25 (i.e., the pulse currents supplied from the first pulse signal generator SW4A to the head core WH2A as shown in FIG. 23) are in-phase signals. Also, the pulse currents used in gap pattern G26 (i.e., the pulse currents supplied from the second pulse signal generator SW4B to the head core WH2B as shown in FIG. 23) are in-phase currents. In other words, the pulse currents used in units of head core WH2 are in-phase currents.

[0231] 24, servo bands SB1, SB2, SB3, SB4, SB5, and SB6 and data bands DB1, DB2, DB3, DB4, and DB5 are formed on the surface 31 of the magnetic tape MT. The servo bands SB1 to SB6 are examples of "servo bands" according to the technology of the present disclosure. Note that, for convenience of explanation, the servo bands SB1 to SB6 will be referred to as servo bands SB, and the data bands DB1 to DB5 will be referred to as data bands DB, unless a distinction is particularly needed.

[0232] Data band DB1 is arranged between servo band SB1 and servo band SB2, and data band DB2 is arranged between servo band SB2 and servo band SB3. Data band DB3 is arranged between servo band SB3 and servo band SB4. Data band DB4 is arranged between servo band SB4 and servo band SB5. Data band DB5 is arranged between servo band SB5 and servo band SB6. In other words, servo bands SB and data bands DB are arranged alternately along the width direction WD.

[0233] Here, the servo bands SB6, SB5, SB4, SB3, and SB2 form one servo band set SBP1. In other words, the servo band set SBP1 includes the servo bands SB6, SB5, SB4, SB3, and SB2.

[0234] As described above, in the magnetic tape MT according to the second modification, the plurality of servo patterns 58 corresponding to each other between the servo bands SB are shifted at a predetermined interval in the longitudinal direction LD of the magnetic tape MT between the servo bands SB adjacent in the width direction WD. Furthermore, the servo patterns 58 have recorded therein set identification information for identifying the corresponding sets of servo bands SBP1 and SBP2. Furthermore, the set of servo bands SBP includes five servo bands SB.

[0235] As a result, even if a servo band set SBP includes three servo bands SB, the servo bands SB can be identified based on the predetermined interval difference formed in the servo pattern 58 between adjacent servo bands SB and the information for identifying the servo band sets SBP1 and SBP2. That is, the servo bands SB of the servo band sets SBP1 and SBP2 are identified by a combination of the set identification information PID and the predetermined interval difference between the servo patterns 58. Being able to identify the servo bands SB also means being able to identify the data bands DB present between adjacent servo bands SB. Therefore, this configuration can contribute to identifying the data bands DB even if a servo band set SBP includes five servo bands SB.

[0236] Furthermore, the set identification information PID is recorded using a common pulse current. This allows a common circuit for supplying the pulse current, thereby reducing the pulse current value. For example, compared to when a separate circuit is provided for each servo pattern 58 to supply current, the current value when recording the servo patterns 58 can be reduced. Therefore, this configuration reduces the thermal effects (e.g., thermal contraction of the magnetic tape MT due to heat generated by the servo pattern recording head WH) when recording the servo patterns 58 on the magnetic tape MT.

[0237] In the above embodiment, the predetermined interval is a predetermined value. However, the technology of the present disclosure is not limited to this. For example, the predetermined interval is determined based on the angle α between the corresponding frames 56 of adjacent servo bands SB in the width direction WD and the virtual line C1, and the pitch between adjacent servo bands SB in the width direction WD (i.e., the servo band pitch). In this case, for example, the predetermined interval is calculated using the following formula (2):

[0238] (Predetermined interval) = (Servo band pitch) × tan α (2)

[0239] As described above, the frame length is not included in formula (2). This means that the predetermined interval can be calculated without taking the frame length into consideration. Therefore, with this configuration, the predetermined interval can be calculated more easily than when the predetermined interval is calculated from formula (1).

[0240] In the above embodiment, the magnetic tape system 10 is exemplified as one in which the magnetic tape cartridge 12 is freely insertable into and removable from the magnetic tape drive 14. However, the technology of the present disclosure is not limited to this. For example, the technology of the present disclosure can also be applied to a magnetic tape system in which at least one magnetic tape cartridge 12 is pre-loaded into the magnetic tape drive 14 (i.e., a magnetic tape system in which at least one magnetic tape cartridge 12 and the magnetic tape drive 14 are pre-integrated).

[0241] Although the above embodiment illustrates a single magnetic head 28, the technology of the present disclosure is not limited to this. For example, multiple magnetic heads 28 may be arranged on the magnetic tape MT. For example, a read magnetic head 28 and at least one write magnetic head 28 may be arranged on the magnetic tape MT. The read magnetic head 28 may be used to verify data recorded in the data band DB by the write magnetic head 28. Furthermore, one magnetic head equipped with a read magnetic element unit 42 and at least one write magnetic element unit 42 may be arranged on the magnetic tape MT.

[0242] In the above embodiment, the servo pattern recording head WH has been described as having two head cores WH2A and WH2B, but the technology of the present disclosure is not limited to this. The servo pattern recording head WH may have three or more head cores WH2.

[0243] The above-described description and illustrations are a detailed explanation of the parts related to the technology of the present disclosure and are merely an example of the technology of the present disclosure. For example, the above description of the configuration, functions, actions, and effects is an explanation of an example of the configuration, functions, actions, and effects of the parts related to the technology of the present disclosure. Therefore, it goes without saying that unnecessary parts may be deleted, new elements may be added, or replacements may be made to the above-described description and illustrations within the scope of the gist of the technology of the present disclosure. Furthermore, to avoid confusion and facilitate understanding of the parts related to the technology of the present disclosure, the above-described description and illustrations omit explanations of common technical knowledge that do not require particular explanation to enable the implementation of the technology of the present disclosure.

[0244] In this specification, "A and / or B" is synonymous with "at least one of A and B." In other words, "A and / or B" means that it may be only A, only B, or a combination of A and B. Furthermore, in this specification, the same concept as "A and / or B" is also applied when three or more things are expressed by connecting them with "and / or."

[0245] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

[0246] The disclosure of Japanese Patent Application No. 2022-110796, filed on July 8, 2023, is incorporated herein by reference in its entirety.

[0247] The following additional notes are provided regarding the above-described embodiments.

[0248] (Supplementary Note 1) A servo pattern recording head comprising: a plurality of magnetically separated head cores; and a plurality of gap patterns formed on the surface of each of the plurality of head cores, and recording a plurality of servo patterns in the width direction of the magnetic tape by applying a magnetic field to the magnetic tape in accordance with a pulse current, wherein the plurality of gap patterns are formed on the surface along a direction corresponding to the width direction, and the plurality of gap patterns are shifted at a predetermined interval in a direction corresponding to the longitudinal direction of the magnetic tape between gap patterns adjacent in the direction corresponding to the width direction. (Supplementary Note 2) The servo pattern recording head according to Supplementary Note 1, wherein information indicated by the pulse current includes identification information for identifying the plurality of servo patterns on a head core-by-head core basis. (Supplementary Note 3) The servo pattern recording head according to Supplementary Note 2, wherein the identification information is common to each head core. (Supplementary Note 4) The servo pattern recording head according to any one of Supplements 1 to 3, wherein the plurality of gap patterns are arranged in a common manner between the head cores. (Supplementary Note 5) The servo pattern recording head according to any one of Supplementary Note 1 to Supplementary Note 4, wherein the pulse currents used for each head core are in phase. (Supplementary Note 6) A servo pattern recording device comprising: the servo pattern recording head according to any one of Supplementary Note 1 to Supplementary Note 5; and a pulse signal generator that supplies the pulse currents to the plurality of head cores, wherein the pulse signal generator is provided for each of the plurality of head cores. (Supplementary Note 7) A magnetic tape on which the servo patterns are recorded using the servo pattern recording head according to any one of Supplementary Note 1 to Supplementary Note 5.

Claims

1. A servo pattern recording head comprising: a plurality of magnetically separated head cores; and a plurality of gap patterns formed on the surface of each of the plurality of head cores, which record a plurality of servo patterns in the width direction of the magnetic tape by applying a magnetic field to the magnetic tape in accordance with a pulse current, wherein the plurality of gap patterns are formed on the surface along a direction corresponding to the width direction, and the plurality of gap patterns are offset at a predetermined interval in a direction corresponding to the longitudinal direction of the magnetic tape between gap patterns adjacent to each other along the direction corresponding to the width direction.

2. The servo pattern recording head according to claim 1, wherein the information indicated by the pulse current includes identification information for identifying the plurality of servo patterns for each head core.

3. The servo pattern recording head according to claim 2, wherein the identification information is common to each head core.

4. The servo pattern recording head according to claim 1, wherein the plurality of gap patterns are arranged in a common manner between the head cores.

5. The servo pattern recording head according to claim 1, wherein the pulse currents used in each head core are in phase.

6. A servo pattern recording device comprising: the servo pattern recording head according to any one of claims 1 to 5; and a pulse signal generator that supplies the pulse current to the plurality of head cores, wherein the pulse signal generator is provided for each of the plurality of head cores.

7. A magnetic tape on which a servo pattern is recorded using the servo pattern recording head according to any one of claims 1 to 5.

8. A magnetic tape cartridge comprising: the magnetic tape according to claim 7; and a case in which the magnetic tape is housed.

9. A magnetic tape drive comprising: a running mechanism for running the magnetic tape according to claim 7 along a predetermined path; and a magnetic head for reading the servo pattern on the predetermined path while the magnetic tape is being run by the running mechanism.

10. A magnetic tape system comprising: the magnetic tape according to claim 7; and a magnetic tape drive equipped with a magnetic head that reads the servo pattern on a predetermined path while the magnetic tape is running along the predetermined path.

11. A method for manufacturing a magnetic tape, comprising: supplying a pulse current to a plurality of magnetically separated head cores; and recording a plurality of servo patterns in the width direction of the magnetic tape by applying a magnetic field to the magnetic tape in accordance with the pulse current via a plurality of gap patterns formed on the surface of each of the plurality of head cores, wherein the plurality of gap patterns are formed on the surface in a direction corresponding to the width direction, and the plurality of gap patterns are offset at a predetermined interval in a direction corresponding to the longitudinal direction of the magnetic tape between gap patterns adjacent to each other in the direction corresponding to the width direction.

12. The method for manufacturing a magnetic tape according to claim 11, wherein the information indicated by the pulse current includes identification information for identifying the plurality of servo patterns for each head core.

13. A magnetic tape having a plurality of sets of servo bands formed in the width direction, and a plurality of servo patterns arranged along the longitudinal direction of the servo bands, wherein pairs of corresponding servo patterns between the servo bands are shifted at a predetermined interval in the longitudinal direction of the magnetic tape between adjacent servo bands in the width direction, and wherein set identification information for identifying the sets is recorded in the servo patterns.

14. The magnetic tape according to claim 13, wherein the set includes at least three servo bands.

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