JP7892425B2 - 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 - Google Patents

Description

The technologies disclosed herein relate to servo pattern recording devices, magnetic tapes, magnetic tape cartridges, magnetic tape drives, magnetic tape systems, detection devices, inspection devices, servo pattern recording methods, magnetic tape manufacturing methods, detection methods, and inspection methods.

Patent Document 1 addresses the problem in magnetic tape devices where read and/or write errors occur when the tape does not pass through the head with appropriate tension and/or skew angle. To solve this problem, the system described in Patent Document 1 includes a head having at least one array of readers and writers, a drive mechanism for passing the magnetic recording tape over the head, and a skew induction mechanism coupled to the head. This mechanism adjusts the skew angle of the vertical axis of the array with respect to the direction perpendicular to the direction in which the tape moves over the head, and a controller that communicates with the head. Furthermore, the system in Patent Document 1 determines the tape dimensional stability state of the tape, adjusts the skew angle away from the normal to the direction of tape movement, and reduces the overall tape tension of the head if the tape dimensional stability state is a contracted state.

Patent Document 2 discloses a method for reading data tracks on a magnetic tape exhibiting lateral distortion by selectively using vertically offset reading elements. The reading elements are part of a tape head with an azimuth angle to the tape, creating a lateral offset between them. This lateral offset is used to minimize the effects of lateral tape distortion.

Patent Document 3 discloses a head device comprising: a head section in which multiple magnetic elements, each performing at least one of the following actions—reproduction of data recorded on multiple data tracks on a magnetic tape and recording data to each of the data tracks—are arranged at equal intervals on a first straight line; a moving mechanism for moving the head section; and a control unit that performs tracking control to on-track each of the magnetic elements to each of the data tracks by moving the head section relative to the moving mechanism. In the head device described in Patent Document 3, the moving mechanism is configured to be capable of rotational drive, which increases or decreases the angle between a second straight line and a first straight line along the width of the magnetic tape. During the execution of tracking control, the control unit rotates the head section relative to the moving mechanism by an amount of angle increase or decrease corresponding to the change in the spacing between each data track, thereby on-tracking each of the magnetic elements to each data track.

Patent Document 4 describes a method for forming a servo track configuration, comprising the steps of forming at least one servo track having a width, and repeatedly recording a servo pattern within the servo track, wherein the recording step includes repeatedly recording first and second reference pattern lines and a track pattern line simultaneously within the servo track. Each of the first and second reference pattern lines has the same predetermined shape and extends across the width of the servo track, and furthermore, the track pattern line has a predetermined shape different from the predetermined shapes of the first and second reference pattern lines and extends across the width of the servo track.

Patent Document 5 describes a magnetic tape reading device comprising: an acquisition unit that acquires information regarding the linearity of a servo pattern recorded on the servo band of the magnetic tape of a magnetic tape cartridge; a reading element unit in which at least two reading elements, each reading data from a specific track area including the track to be read using a linear scan method within the track area of the magnetic tape, are arranged in close proximity; a servo reading element that reads the servo pattern; a control unit that performs positioning control of the reading element unit using the reading signal of the servo pattern read by the servo reading element and the linearity information acquired by the acquisition unit; a derivation unit that derives the amount of positional displacement between the magnetic tape and the reading element unit using the reading signal of the servo pattern while the control unit is performing control; and an extraction unit that extracts data recorded on the track to be read from the reading results by applying waveform equalization processing to each reading result for each reading element according to the amount of displacement derived by the derivation unit.

U.S. Patent No. 8094402 U.S. Patent No. 6781784 Japanese Patent Publication No. 2009-123288 Japanese Patent Publication No. 2000-260014 Japanese Patent Publication No. 2020-140744

One embodiment of the technology described herein provides a servo pattern recording apparatus, 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 that can obtain highly reliable servo signals.

A first aspect of the technology of this disclosure is a servo pattern recording apparatus comprising a pulse signal generator and a servo pattern recording head, wherein the pulse signal generator generates a pulse signal, and the servo pattern recording head has a substrate and a plurality of gap patterns formed on the surface of the substrate, and records a plurality of servo patterns in the width direction of the magnetic tape by applying a magnetic field to the magnetic tape from the plurality of gap patterns according to the pulse signal, wherein the plurality of gap patterns are formed on the surface along a direction corresponding to the width direction, and the gap pattern is at least one pair of linear regions, a first linear region which is one of the linear regions of the pair of linear regions, and a linear region This servo pattern recording device has a second linear region, which is the other linear region of a pair of regions, tilted in a direction opposite to the first virtual line along the direction corresponding to the width direction on the surface, the first linear region having a steeper tilt angle with respect to the first virtual line than the second linear region, the positions of both ends of the first linear region and the positions of both ends of the second linear region being aligned in the direction corresponding to the width direction of the magnetic tape, multiple gap patterns being offset 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, and the base being tilted along the magnetic tape with respect to the first virtual line at an angle that absorbs the predetermined interval offset.

A second aspect of the technology of this disclosure is a servo pattern recording device according to the first aspect, wherein the substrate is formed in the shape of a rectangular parallelepiped and diagonally traverses the magnetic tape.

A third aspect of the technology of this disclosure is a servo pattern recording device according to the second aspect, wherein the surface is formed in a rectangular shape having a long side and a short side, and the length of the short side is such that multiple servo patterns can be accommodated.

A fourth aspect of the technology of this disclosure is a servo pattern recording device according to any one of the first to third aspects, wherein the total length of the first linear region is shorter than the total length of the second linear region.

A fifth aspect of the technology of this disclosure is a servo pattern recording device according to any one of the first to fourth aspects, wherein the geometric characteristics on the surface of a pair of linear regions correspond to the geometric characteristics obtained when the entire pair of virtual linear regions is tilted with respect to the first virtual line by tilting the axis of symmetry of the pair of virtual linear regions, which are tilted symmetrically with respect to the first virtual line, with respect to the first virtual line, and the positions of both ends of one of the pair of virtual linear regions are aligned in a direction corresponding to the width direction.

A sixth aspect of the technology of this disclosure is a servo pattern recording device according to any one of the first to fifth aspects, wherein a magnetic tape has a plurality of servo bands formed along its width, the servo bands are separated by frames defined based on at least one set of servo patterns, and the predetermined interval is defined based on the angle between corresponding frames in the width direction of adjacent servo bands and a first virtual line, and the pitch between adjacent servo bands in the width direction.

A seventh aspect of the technology of this disclosure is a servo pattern recording device according to any one of the first to fifth aspects, wherein a magnetic tape has a plurality of servo bands formed along its width, the servo bands are separated by frames defined based on at least one set of servo patterns, and the predetermined interval is defined based on the angle between frames that are not corresponding between adjacent servo bands in the width direction and a first virtual straight line, the pitch between adjacent servo bands in the width direction, and the total length of the frame in the longitudinal direction.

An eighth aspect of the technology of this disclosure is a servo pattern recording device according to any one of the first to seventh aspects, wherein the pulse signals used between multiple gap patterns are in-phase signals.

A ninth aspect of the technology of this disclosure is a magnetic tape on which multiple servo patterns are recorded by a servo pattern recording device according to any one of the first to eighth aspects.

A tenth aspect of the technology of this disclosure is a magnetic tape cartridge comprising a magnetic tape according to the ninth aspect and a case containing the magnetic tape.

An eleventh aspect of the technology of this disclosure is a magnetic tape drive comprising: a travel mechanism for traveling a magnetic tape according to the ninth aspect along a predetermined path; and a magnetic head having a plurality of servo reading elements for reading a servo pattern on the predetermined path while the magnetic tape is being traveled by the travel mechanism, wherein the plurality of servo reading elements are arranged along the longitudinal direction of the magnetic head, and the magnetic head is positioned in a posture in which a second virtual straight line along the longitudinal direction of the magnetic head is inclined with respect to the travel direction of the magnetic tape.

A twelfth aspect of the technology of this disclosure is a magnetic tape system comprising a magnetic tape according to the ninth aspect, and a magnetic tape drive equipped with a magnetic head having a plurality of servo reading elements for reading a servo pattern on a predetermined path while the magnetic tape is traveling along the predetermined path, wherein the plurality of servo reading elements are arranged along the longitudinal direction of the magnetic head, and the magnetic head is positioned in a posture in which a third virtual straight line along the longitudinal direction of the magnetic head is inclined with respect to the direction of travel of the magnetic tape.

A thirteenth aspect of the technology of this disclosure is a detection device comprising a processor, wherein the processor detects a servo signal, which is the result of reading a servo pattern from a magnetic tape according to the ninth aspect, using an autocorrelation coefficient.

A fourteenth aspect of the technology of this disclosure is a servo pattern recording method that includes generating a pulse signal and recording a plurality of servo patterns in the width direction of a magnetic tape by applying a magnetic field to the magnetic tape from the plurality of gap patterns in accordance with the pulse signal using a servo pattern recording head having a substrate and a plurality of gap patterns formed on the surface of the substrate, wherein the plurality of gap patterns are formed on the surface along a direction corresponding to the width direction, and each gap pattern is at least one pair of linear regions, and a first linear region which is one of the linear regions of the pair of linear regions and a second linear region which is the other linear region of the pair of linear regions are tilted in directions opposite to a first virtual line along the direction corresponding to the width direction on the surface, the tilt angle of the first linear region with respect to the first virtual line is steeper than that of the second linear region, the positions of both ends of the first linear region and the positions of both ends of the second linear region are aligned in the direction corresponding to the width direction of the magnetic tape, the plurality of gap patterns are offset 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, and the substrate is tilted along the magnetic tape with respect to the first virtual line at an angle that absorbs the offset at predetermined intervals.

A fifteenth aspect of the technology of this disclosure is a method for manufacturing a magnetic tape, comprising: a first step of recording a plurality of servo patterns on a magnetic tape according to the servo pattern recording method of the fourteenth aspect; and a second step of winding up the magnetic tape.

A sixteenth aspect of the technology of this disclosure is a detection device according to the thirteenth aspect, comprising: a detection device used together with a servo pattern recording device according to the first aspect; and an inspection processor that performs inspection of a servo band on which a servo pattern is recorded on a magnetic tape based on a servo signal detected by the detection device.

A 17th aspect of the technology of this disclosure is a detection method used in conjunction with the servo pattern recording method of the 14th aspect, which includes detecting a servo signal, which is the result of reading a servo pattern from a magnetic tape according to the 9th aspect, using an autocorrelation coefficient.

An eighteenth aspect of the technology of this disclosure is an inspection method that includes inspecting a servo band on a magnetic tape where a servo pattern is recorded, based on a servo signal detected by the detection method of the seventeenth aspect.

This is a block diagram showing an example of the configuration of a magnetic tape system according to the embodiment. This is a schematic perspective view showing an example of the appearance of a magnetic tape cartridge according to the embodiment. This is a schematic diagram showing an example of the hardware configuration of a magnetic tape drive according to the embodiment. This is a schematic perspective view showing an example of a configuration in which a magnetic field is emitted from the lower side of a magnetic tape cartridge according to the embodiment by a non-contact reading/writing device. This is a schematic diagram showing an example of the hardware configuration of a magnetic tape drive according to the embodiment. This is a conceptual diagram showing an example of a configuration in which a magnetic head is positioned on a conventionally known magnetic tape, as observed from the surface side of the magnetic tape. This is a conceptual diagram showing an example of how a magnetic tape, before and after a conventionally known shrinkage in width, can be observed from the surface side of the magnetic tape. This is a conceptual diagram showing an example of an observation of a state in which a magnetic head is skewed on a conventionally known magnetic tape, viewed from the surface side of the magnetic tape. This is a conceptual diagram showing an example of a magnetic tape according to the embodiment as observed from the surface side of the magnetic tape. This is a conceptual diagram illustrating an example of the relationship between the geometric characteristics of an actual servo pattern and the geometric characteristics of a virtual servo pattern. This is a conceptual diagram showing an example of an observation from the surface side of a magnetic tape in which corresponding frames are offset by a predetermined interval between adjacent servo bands in the width direction of the magnetic tape according to the embodiment. This is a conceptual diagram showing an example of an observation from the surface side of a magnetic tape in which a servo pattern is read by a servo reading element included in a magnetic head that is not skewed on the magnetic tape according to the embodiment. This is a conceptual diagram showing an example of an observation from the surface side of a magnetic tape in which a servo pattern is read by a servo reading element included in a skewed magnetic head on a magnetic tape according to the embodiment. This is a conceptual diagram showing an example of the functions of a control device included in a magnetic tape drive according to the embodiment. This is a conceptual diagram showing an example of the processing content of the position detection unit and control unit of the control device included in the magnetic tape drive according to the embodiment. This is a conceptual diagram showing an example of the configuration of a servo writer according to the embodiment. This 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 the embodiment, and an example of a view of the servo pattern recording head included in the servo writer according to the embodiment being positioned on a magnetic tape, observed from the surface side of the magnetic tape (i.e., the back side of the servo pattern recording head). This is a conceptual diagram showing an example of how the servo pattern recording head included in the servo writer according to the embodiment is positioned on the magnetic tape, as observed from the surface side of the magnetic tape (i.e., the back side of the servo pattern recording head). This is a conceptual diagram illustrating an example of the relationship between the geometric properties of an actual gap pattern and the geometric properties of a hypothetical gap pattern. This is a conceptual diagram showing an example of how the servo pattern recording head of a comparative example is positioned on a magnetic tape, as observed from the surface side of the magnetic tape (i.e., the back side of the servo pattern recording head). This is a conceptual diagram showing a first modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of how the magnetic tape according to the first modified example is observed from the surface side of the magnetic tape). This is a conceptual diagram showing an example of a servo pattern included in a magnetic tape according to the first modified example. This is a conceptual diagram showing a first modified servo pattern recording head included in the servo writer according to the embodiment (a conceptual diagram showing an example of how the servo pattern recording head according to the first modified embodiment is arranged on a magnetic tape and observed from the surface side of the magnetic tape (i.e., the back side of the servo pattern recording head)). This is a conceptual diagram showing a second modified example of the magnetic tape according to the embodiment (a conceptual diagram showing an example of how the magnetic tape according to the second modified example is observed from the surface side of the magnetic tape). This is a conceptual diagram showing an example of a servo pattern included in a magnetic tape according to the second modified example. This is a conceptual diagram showing a second modified servo pattern recording head included in the servo writer according to the embodiment (a conceptual diagram showing an example of how the servo pattern recording head according to the second modified embodiment is arranged on a magnetic tape and observed from the surface side of the magnetic tape (i.e., the back side of the servo pattern recording head)). This is a conceptual diagram showing an example of an observation from the surface side of a magnetic tape in which corresponding frames are offset by a predetermined interval between adjacent servo bands in the width direction of the magnetic tape according to the embodiment.

The following describes examples of embodiments of the servo pattern recording apparatus, 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 related to the technology of this disclosure, in accordance with the attached drawings.

First, let's explain the terminology used in the following explanation.

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

As an example, as shown in Figure 1, the magnetic tape system 10 comprises 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 the magnetic tape MT from the loaded magnetic tape cartridge 12, and while the pulled-out magnetic tape MT is running, it records data to the magnetic tape MT and reads data from the magnetic tape MT.

In this embodiment, the magnetic tape MT is an example of a "magnetic tape" according to the technology of this disclosure. Furthermore, in this embodiment, the magnetic tape system 10 is an example of a "magnetic tape system" according to the technology of this disclosure. Also, in this embodiment, the magnetic tape drive 14 is an example of a "magnetic tape drive" and "detection device" according to the technology of this disclosure. Furthermore, in this embodiment, the magnetic tape cartridge 12 is an example of a "magnetic tape cartridge" according to the technology of this disclosure.

Next, an example of the configuration of the magnetic tape cartridge 12 will be described with reference to Figures 2 to 4. For the sake of clarity, in the following explanation, in Figures 2 to 4, the loading direction of the magnetic tape cartridge 12 into the magnetic tape drive 14 is indicated by arrow A, and the direction of arrow A is considered the forward direction of the magnetic tape cartridge 12. The side of the magnetic tape cartridge 12 facing forward is referred to as 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.

Furthermore, for the sake of clarity in the following explanation, in Figures 2 to 4, the direction of arrow B, which is perpendicular to the direction of arrow A, will be referred to as the right direction, and the right side of the magnetic tape cartridge 12 will be referred to 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.

Furthermore, for the sake of clarity in the following explanation, in Figures 2 to 4, the direction opposite to arrow B will be referred to as the left direction, and the left side of the magnetic tape cartridge 12 will be 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.

Furthermore, for the sake of clarity in the following explanation, in Figures 2 to 4, the direction perpendicular to arrows A and B is indicated by arrow C. The direction of arrow C is considered the upward direction of the magnetic tape cartridge 12, and the upward side of the magnetic tape cartridge 12 is referred to as the upper side of the magnetic tape cartridge 12. In the following description of the structure, "upper" refers to the upper side of the magnetic tape cartridge 12.

Furthermore, for the sake of clarity in the following explanation, in Figures 2 to 4, the direction opposite to the forward direction of the magnetic tape cartridge 12 will be referred to as the rear direction of the magnetic tape cartridge 12, and the side of the magnetic tape cartridge 12 in the rear direction will be 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.

Furthermore, for the sake of clarity in the following explanation, in Figures 2 to 4, the direction opposite to the upward direction of the magnetic tape cartridge 12 will be referred to as the downward direction, and the downward side of the magnetic tape cartridge 12 will be 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.

As an example, as shown in Figure 2, the magnetic tape cartridge 12 is approximately rectangular in plan view and comprises a box-shaped case 16. The case 16 is an example of a "case" according to the technology of this disclosure. The case 16 houses the magnetic tape MT. The case 16 is made of a resin such as polycarbonate and comprises 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 edge surface of the upper case 18 and the upper peripheral edge surface of the lower case 20 in contact. The joining method is not limited to welding and screw fastening; other joining methods may also be used.

The case 16 rotatably houses the delivery reel 22. The delivery reel 22 comprises a reel hub 22A, an upper flange 22B1, and a lower flange 22B2. The reel hub 22A is cylindrical in shape. The reel hub 22A is the axial center of the delivery reel 22, its axial direction aligns with the vertical direction of the case 16, and it is located in the center of the case 16. The upper flange 22B1 and the lower flange 22B2 are each annular in shape. The upper end of the reel hub 22A is fixed to the central part of the upper flange 22B1 in plan view, and the lower end of the reel hub 22A is fixed to the central part of the lower flange 22B2 in plan view. Note that the reel hub 22A and the lower flange 22B2 may be integrally molded.

A magnetic tape MT is wound around the outer circumferential surface of the reel hub 22A, and the ends of the magnetic tape MT in the width direction are held by the upper flange 22B1 and the lower flange 22B2.

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

The lower case 20 is provided with a cartridge memory 24. Specifically, the cartridge memory 24 is housed in the right rear end of the lower case 20. The cartridge memory 24 is equipped with an IC chip having an NVM (Non-Visible Memory). In this embodiment, a so-called passive RFID tag is used as the cartridge memory 24, and various types of information are read and written to the cartridge memory 24 without contact.

The cartridge memory 24 stores management information for managing the magnetic tape cartridge 12. This management information includes, for example, information about the cartridge memory 24 (e.g., information that can identify the magnetic tape cartridge 12), information about the magnetic tape MT (e.g., 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 data items 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 (e.g., information indicating the specifications of the magnetic tape drive 14, and signals used by the magnetic tape drive 14).

As an example, as shown in Figure 3, the magnetic tape drive 14 includes a transport device 26, a magnetic head 28, a control device 30, a storage device 32, a UI device 34, and a communication interface 35. A magnetic tape cartridge 12 is loaded into the magnetic tape drive 14 along 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.

The magnetic tape MT has a magnetic layer 29A, a base film 29B, and a back coat layer 29C. The magnetic layer 29A is formed on one side of the base film 29B, and the back coat layer 29C is formed on the other side of the base film 29B. Data is recorded on the magnetic layer 29A. The magnetic layer 29A contains ferromagnetic powder. As the ferromagnetic powder, for example, a ferromagnetic powder commonly used in the magnetic layer of various magnetic recording media is used. A preferred specific example of the ferromagnetic powder is hexagonal ferrite powder. Examples of hexagonal ferrite powder include hexagonal strontium ferrite powder or hexagonal barium ferrite powder. The back coat layer 29C is a layer containing non-magnetic powder such as carbon black. The base film 29B is also called a support and 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 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.

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., data playback). In this embodiment, the magnetic tape drive 14 selectively performs data recording on the surface 31 of the magnetic tape MT and data reading from the surface 31 of the magnetic tape MT using the magnetic head 28. That is, the magnetic tape drive 14 pulls the magnetic tape MT from the magnetic tape cartridge 12, and then uses the magnetic head 28 to record data on the surface 31 of the pulled-out magnetic tape MT, or to read data from the surface 31 of the pulled-out magnetic tape MT using the magnetic head 28.

The control device 30 controls the entire magnetic tape drive 14. In this embodiment, the control device 30 is implemented by an ASIC, but the technology of this disclosure is not limited thereto. For example, the control device 30 may be implemented by an FPGA and/or a PLC. Alternatively, the control device 30 may be implemented by a computer including a CPU, flash memory (e.g., EEPROM, and/or SSD), and RAM. Furthermore, it may be implemented by a combination of two or more of the ASIC, FPGA, PLC, and computer. In other words, the control device 30 may be implemented by a combination of hardware and software configurations. Note that the control device 30 is an example of a "processor" according to the technology of this disclosure.

The storage device 32 is connected to the control device 30, which writes various types of information to and reads various types of information from the storage device 32. An example of the storage device 32 is a flash memory and/or HDD. Flash memory and HDD are merely examples; any non-volatile memory that can be mounted on the magnetic tape drive 14 may be used.

The UI device 34 is a device having a reception function that receives instruction signals indicating instructions from the user, and a presentation function that presents information to the user. The reception function is implemented, for example, by a touch panel, hard keys (e.g., a keyboard), and/or a mouse. The presentation function is implemented, for example, by a display, printer, and/or 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. Under the control of the control device 30, the UI device 34 presents various types of information to the user.

The communication interface 35 is connected to the control device 30. Furthermore, the communication interface 35 is connected to an external device 37 via a communication network such as a WAN and/or LAN (not shown). The communication interface 35 is responsible for the exchange of various types of information between the control device 30 and the external device 37 (e.g., recording data for the magnetic tape MT, data read from the magnetic tape MT, and/or instruction signals given to the control device 30). Examples of the external device 37 include a personal computer or a mainframe.

The transport device 26 is a device that selectively transports the magnetic tape MT along a predetermined path in the forward and reverse directions, and comprises a feed motor 36, a take-up reel 38, a take-up motor 40, and a plurality of guide rollers GR. Here, "forward direction" refers to the direction in which the magnetic tape MT is fed out, and "reverse direction" refers to the direction in which the magnetic tape MT is rewound. In this embodiment, the transport device 26 is an example of a "travel mechanism" related to the technology of this disclosure.

The feed motor 36 rotates the feed reel 22 inside the magnetic tape cartridge 12 under the control of the control device 30. The control device 30 controls the direction of rotation, rotation speed, and rotation torque of the feed reel 22 by controlling the feed motor 36.

The winding motor 40 rotates the winding reel 38 under the control of the control device 30. The control device 30 controls the winding motor 40, thereby controlling the rotation direction, rotation speed, and rotation torque of the winding reel 38.

When the magnetic tape MT is being wound onto the take-up reel 38, the control device 30 rotates the feed motor 36 and the take-up motor 40 so that the magnetic tape MT travels forward along a predetermined path. The rotational speed and torque of the feed motor 36 and the take-up motor 40 are adjusted according to the speed at which the magnetic tape MT is wound onto the take-up reel 38. Furthermore, tension is applied to the magnetic tape MT by adjusting the rotational speed and torque of the feed motor 36 and the take-up motor 40, respectively, as controlled by the control device 30. The tension applied to the magnetic tape MT is controlled by adjusting the rotational speed and torque of the feed motor 36 and the take-up motor 40, respectively, as controlled by the control device 30.

Furthermore, when rewinding the magnetic tape MT onto the feed reel 22, the control device 30 rotates the feed motor 36 and the take-up motor 40 so that the magnetic tape MT travels in the reverse direction along a predetermined path.

In this embodiment, the tension applied to the magnetic tape MT is controlled by controlling the rotational speed and rotational torque of the delivery motor 36 and the winding motor 40, but the technology of this disclosure is not limited to this. For example, the tension applied to the magnetic tape MT may be controlled using a dancer roller, or it may be controlled by pulling the magnetic tape MT into a vacuum chamber.

Each of the multiple guide rollers GR is a roller that guides the magnetic tape MT. The predetermined path, that is, the travel path of the magnetic tape MT, is determined by the arrangement of the multiple guide rollers GR between the magnetic tape cartridge 12 and the take-up reel 38, at positions that straddle the magnetic head 28.

The magnetic head 28 comprises a magnetic element unit 42 and a holder 44. The magnetic element unit 42 is held by the holder 44 so as to contact the magnetic tape MT while it is moving. The magnetic element unit 42 has multiple magnetic elements.

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 pattern 58 (see Figure 9), and data other than the servo pattern 58, i.e., data recorded in the data band DB (see Figure 9).

The magnetic tape drive 14 is equipped with a non-contact read/write device 46. The non-contact read/write device 46 is positioned on the underside of the magnetic tape cartridge 12 when the magnetic tape cartridge 12 is loaded, facing the back surface 24A of the cartridge memory 24, and performs non-contact reading and writing of information to the cartridge memory 24.

As an example, as shown in Figure 4, the non-contact reading/writing device 46 emits a magnetic field MF from the underside of the magnetic tape cartridge 12 toward the cartridge memory 24. The magnetic field MF penetrates the cartridge memory 24.

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. This control signal controls the cartridge memory 24. The non-contact read/write device 46 generates a magnetic field MF according to the control signal input from the control device 30 and emits the generated magnetic field MF towards the cartridge memory 24.

The contactless read/write device 46 performs contactless communication with the cartridge memory 24 via a magnetic field (MF), thereby processing the cartridge memory 24 according to the control signal. For example, under the control of the control device 30, the contactless read/write device 46 selectively performs the process of reading information from the cartridge memory 24 and the process of storing information in the cartridge memory 24 (i.e., the process of writing information to the cartridge memory 24).

As an example, as shown in Figure 5, the magnetic tape drive 14 includes a moving mechanism 48. The moving mechanism 48 has a moving actuator 48A. Examples of the moving actuator 48A include a voice coil motor and/or a piezo actuator. The moving actuator 48A is connected to a control device 30, which controls the moving actuator 48A. The moving actuator 48A generates power under the control of the control device 30. The moving mechanism 48 moves the magnetic head 28 in the width direction of the magnetic tape MT by receiving the power generated by the moving actuator 48A.

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 piezo actuator. The tilt actuator 49A is connected to a control device 30, which controls the tilt actuator 49A. The tilt actuator 49A generates power under the control of the control device 30. The tilt mechanism 49, receiving the power generated by the tilt actuator 49A, tilts the magnetic head 28 toward the longitudinal direction LD of the magnetic tape MT relative to the width direction WD (see Figure 8). That is, the magnetic head 28 skews on the magnetic tape MT under the control of the control device 30.

Here, as a comparative example to magnetic tape MT, the case where the conventionally known magnetic tape MT0 is used instead of magnetic tape MT will be explained with reference to Figures 6 to 8. Note that when comparing magnetic tape MT0 and magnetic tape MT, the difference is that magnetic tape MT0 has servo pattern 52 (see Figure 6) applied, while magnetic tape MT has servo pattern 58 (see Figure 9) applied.

As an example, as shown in Figure 6, the surface 31 of the magnetic tape MT0 has servo bands SB1, SB2, and SB3, and data bands DB1 and DB2 formed thereon. For the sake of clarity, unless otherwise specified, servo bands SB1 to SB3 will be referred to as servo bands SB, and data bands DB1 and DB2 will be referred to as data bands DB.

The servo bands SB1 to SB3 and data bands DB1 and DB2 are formed along the longitudinal direction LD (i.e., the overall length direction) of the magnetic tape MT0. Here, the overall length direction LD of the magnetic tape MT0 refers to the direction in which the magnetic tape MT0 travels. The direction in which the magnetic tape MT0 travels is defined by two directions: the forward direction (hereinafter simply referred to as "forward direction"), which is the direction in which the magnetic tape MT0 travels from the feed reel 22 side to the take-up reel 38 side, and the reverse direction (hereinafter simply referred to as "reverse direction"), which is the direction in which the magnetic tape MT0 travels from the take-up reel 38 side to the feed reel 22 side.

The servo bands SB1 to SB3 are arranged at spaced positions along the width direction WD (hereinafter also simply referred to as "width direction WD") of the magnetic tape MT0. For example, the servo bands SB1 to SB3 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 an error that is generally acceptable in the art to which this disclosure pertains, and does not contradict the spirit of this disclosure.

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

Note that while Figure 6 shows three servo bands SB and two data bands DB for illustrative purposes, this is merely an example. The technology of this disclosure also applies to two servo bands SB and one data band DB, or even four or more servo bands SB and three or more data bands DB.

Multiple servo patterns 52 are recorded in the servo band SB along the longitudinal LD of the magnetic tape MT0. The servo patterns 52 are classified into servo patterns 52A and servo patterns 52B. The multiple servo patterns 52 are arranged at regular intervals along the longitudinal LD of the magnetic tape MT0. In this embodiment, "regular" refers not only to perfect regularity but also to regularity that includes errors generally acceptable in the art to which the disclosed technology belongs, and that do not contradict the spirit of the disclosed technology.

The servo band SB is divided into multiple frames 50 along the longitudinal direction LD of the magnetic tape MT0. Each frame 50 is defined by a pair of servo patterns 52. In the example shown in Figure 6, servo patterns 52A and 52B are shown as an example of a pair of servo patterns 52. Servo patterns 52A and 52B are adjacent along the longitudinal direction LD of the magnetic tape MT0, with servo pattern 52A located on the upstream side in the forward direction and servo pattern 52B located on the downstream side in the forward direction within the frame 50.

The servo pattern 52 consists of linear magnetization region pairs 54. The linear magnetization region pairs 54 are classified into linear magnetization region pairs 54A and linear magnetization region pairs 54B.

The servo pattern 52A consists of a pair of linear magnetization regions 54A. In the example shown in Figure 6, linear magnetization regions 54A1 and 54A2 are shown as an example of a pair of linear magnetization regions 54A. Each of the linear magnetization regions 54A1 and 54A2 is a linearly magnetized region.

The linear magnetization regions 54A1 and 54A2 are inclined in directions opposite to a virtual straight line C1, which is a virtual straight line along the width direction WD. In the example shown in Figure 6, the linear magnetization regions 54A1 and 54A2 are inclined symmetrically with respect to the virtual straight line C1. More specifically, the linear magnetization regions 54A1 and 54A2 are non-parallel to each other and are formed inclined by a predetermined angle (e.g., 5 degrees) in opposite directions on the longitudinal direction LD side of the magnetic tape MT0, with the virtual straight line C1 as the axis of symmetry. In this embodiment, the virtual straight line C1 is an example of a "first virtual straight line" according to the technology of this disclosure.

A linear magnetization region 54A1 is a set of five magnetized straight lines, known as magnetization lines 54A1a. A linear magnetization region 54A2 is a set of five magnetized straight lines, known as magnetization lines 54A2a.

The servo pattern 52B consists of a pair of linear magnetization regions 54B. In the example shown in Figure 6, linear magnetization regions 54B1 and 54B2 are shown as examples of the pair of linear magnetization regions 54B. Each of the linear magnetization regions 54B1 and 54B2 is a linearly magnetized region.

The linear magnetization regions 54B1 and 54B2 are inclined in directions opposite to a virtual straight line C2, which is a virtual straight line along the width direction WD. In the example shown in Figure 6, the linear magnetization regions 54B1 and 54B2 are inclined symmetrically with respect to the virtual straight line C2. More specifically, the linear magnetization regions 54B1 and 54B2 are non-parallel to each other and are formed inclined by a predetermined angle (e.g., 5 degrees) in opposite directions on the longitudinal direction LD side of the magnetic tape MT0, with the virtual straight line C2 as the axis of symmetry. In this embodiment, the virtual straight line C2 is an example of the "first virtual straight line" according to the technology of this disclosure.

A linear magnetization region 54B1 is a set of four magnetized straight lines, known as magnetization lines 54B1a. A linear magnetization region 54B2 is a set of four magnetized straight lines, known as magnetization lines 54B2a.

The magnetic head 28 is positioned on the surface 31 side of the magnetic tape MT0 configured in this way. The holder 44 is formed in a rectangular parallelepiped shape and is positioned to traverse the surface 31 of the magnetic tape MT0 along the width direction WD. The multiple magnetic elements of the magnetic element unit 42 are arranged linearly along the longitudinal direction LD of the holder 44. The magnetic element unit 42 includes a pair of servo reading elements SR and multiple data reading/writing elements DRW as multiple magnetic elements. The longitudinal length of the holder 44 is sufficiently long compared to the width of the magnetic tape MT0. For example, the longitudinal length of the holder 44 is set to exceed the width of the magnetic tape MT0 regardless of the position of the magnetic element unit 42 on the magnetic tape MT.

The pair of servo reading elements SR consists of servo reading elements SR1 and SR2. Servo reading element SR1 is located at one end of the magnetic element unit 42, and servo reading element SR2 is located at the other end of the magnetic element unit 42. In the example shown in Figure 6, servo reading element SR1 is located at a position corresponding to servo band SB2, and servo reading element SR2 is located at a position corresponding to servo band SB3.

Multiple data read/write elements (DRWs) are arranged linearly between the servo read element SR1 and the servo read element SR2. The multiple data read/write elements (DRWs) are spaced apart along the longitudinal direction of the magnetic head 28 (for example, equally spaced along the longitudinal direction of the magnetic head 28). In the example shown in Figure 6, the multiple data read/write elements (DRWs) are located at positions corresponding to the data band DB2.

The control device 30 acquires a servo signal, which is the result of reading the servo pattern 52 by the servo reading element SR, and performs servo control according to the acquired servo signal. Here, servo control refers to the control that moves the magnetic head 28 in the width direction WD of the magnetic tape MT0 by operating the movement mechanism 48 according to the servo pattern 52 read by the servo reading element SR.

Through servo control, multiple data read/write elements (DRWs) are positioned over a designated area within the data band DB, and perform magnetic processing on that designated area within the data band DB. In the example shown in Figure 6, magnetic processing is performed on a designated area within the data band DB2 by multiple data read/write elements (DRWs).

Furthermore, when the data band DB targeted for data reading by the magnetic element unit 42 is changed (in the example shown in Figure 6, the data band DB targeted for data reading by the magnetic element unit 42 is changed from data band DB2 to DB1), the moving mechanism 48, under the control of the control device 30, moves the magnetic head 28 in the width direction WD, thereby changing the position of the pair of servo reading elements SR. Specifically, the moving mechanism 48 moves the magnetic head 28 in the width direction WD, moving servo reading element SR1 to a position corresponding to servo band SB1, and moving servo reading element SR2 to a position corresponding to servo band SB2. As a result, the positions of the multiple data reading/writing elements DRW are changed from data band DB2 to data band DB1, and magnetic processing is performed on data band DB1 by the multiple data reading/writing elements DRW.

Incidentally, in recent years, research has been progressing on technologies to reduce the effects of TDS (Transverse Dimensional Stability). TDS is affected by temperature, humidity, the pressure applied to the magnetic tape on the reel, and degradation over time. It is known that without countermeasures, TDS increases, leading to off-track events (i.e., misalignment of the data read/write element DRW relative to the tracks within the data band DB) during magnetic processing of the data band DB.

The example shown in Figure 7 illustrates a scenario where the width of the magnetic tape MT0 shrinks over time. In this case, off-tracking occurs. The width of the magnetic tape MT0 may also expand, and in this case, off-tracking also occurs. That is, if the width of the magnetic tape MT0 shrinks or expands over time, the position of the servo reading element SR relative to the servo pattern 52 deviates in the width direction WD from the design-defined default position (for example, the center position of each of the linear magnetization regions 54A1, 54A2, 54B1, and 54B2). When the position of the servo reading element SR relative to the servo pattern 52 deviates in the width direction WD from the design-defined default position, the accuracy of the servo control decreases, and the position of the track in the data band DB and the data read/write element DRW become misaligned. As a result, magnetic processing is not performed on the originally planned track.

As an example of a method to reduce the effects of TDS, as shown in Figure 8, a method is known in which the position of the servo reading element SR relative to the servo pattern 52 is maintained at a predetermined position as determined by the design by skewing the magnetic head 28 on the magnetic tape MT0.

The magnetic head 28 is provided with a rotation axis RA. The rotation axis RA is located at a position corresponding to the center of the magnetic element unit 42 included in the magnetic head 28 in a plan view. The magnetic head 28 is rotatably held by the tilt mechanism 49 via the rotation axis RA. The magnetic head 28 is provided with a virtual straight line C3, which is a virtual center line. The virtual straight line C3 is a straight line that passes through the rotation axis RA and extends in the longitudinal direction of the magnetic head 28 in a plan view (i.e., the direction in which the multiple data read/write elements DRW are arranged). The magnetic head 28 is held by the tilt mechanism 49 such that the virtual straight line C3 is tilted toward the longitudinal direction of the magnetic tape MT0 with respect to a virtual straight line C4, which is a virtual straight line along the width direction WD. In the example shown in Figure 8, the magnetic head 28 is held by the tilt mechanism 49 in a position where the virtual straight line C3 is tilted toward the feed reel 22 side with respect to the virtual straight line C4 (i.e., tilted counterclockwise when viewed from the front side of the paper in Figure 8). In this embodiment, the virtual line C3 is an example of the "second virtual line" and "third virtual line" related to the technology of this disclosure.

The tilting mechanism 49, receiving power from the tilting actuator 49A (see Figure 5), rotates the magnetic head 28 around the rotation axis RA on the surface 31 of the magnetic tape MT0. Under the control of the control device 30, the tilting mechanism 49 rotates the magnetic head 28 around the rotation axis RA on the surface 31 of the magnetic tape MT0, thereby changing the direction and angle of the inclination (i.e., azimuth) of the virtual line C3 relative to the virtual line C4.

The direction and angle of the inclination of the virtual line C3 relative to the virtual line C4 are changed according to temperature, humidity, the pressure applied to the magnetic tape MT0 when wound onto the reel, and deterioration over time, or the resulting expansion and contraction of the magnetic tape MT in the width direction WD. This ensures that the position of the servo reading element SR relative to the servo pattern 52 is maintained at a predetermined position as defined by the design.

Incidentally, the servo reading element SR is formed linearly along the virtual straight line C3. Therefore, when the servo pattern 52A is read by the servo reading element SR, the angle between the linear magnetization region 54A1 and the servo reading element SR is different from the angle between the linear magnetization region 54A2 and the servo reading element SR in the linear magnetization region pair 54A. When the angles are different in this way, variations due to azimuth loss (for example, variations in signal level and waveform distortion) occur between the servo signal originating from the linear magnetization region 54A1 (i.e., the servo signal obtained when the linear magnetization region 54A1 is read by the servo reading element SR) and the servo signal originating from the linear magnetization region 54A2 (i.e., the servo signal obtained when the linear magnetization region 54A2 is read by the servo reading element SR). In the example shown in Figure 8, the angle between the servo reading element SR and the linear magnetization region 54A1 is larger than the angle between the servo reading element SR and the linear magnetization region 54A2. Therefore, the servo signal output is smaller and the waveform broadens, resulting in variations in the servo signal read by the servo reading element SR across the servo band SB while the magnetic tape MT is running. Furthermore, even when the servo pattern 52B is read by the servo reading element SR, variations due to azimuth loss occur between the servo signal originating from the linear magnetization region 54B1 and the servo signal originating from the linear magnetization region 54B2. Such variations in the servo signal can contribute to a decrease in the accuracy of servo control.

Furthermore, as another example of a conventionally known servo pattern 52A, a configuration in which the linear magnetization region 54A1 is parallel to a virtual straight line C1 and the linear magnetization region 54A2 is inclined with respect to the virtual straight line C1 (i.e., a configuration in which only the linear magnetization region 54A2 is inclined) can be considered. Even in this conventionally known configuration, when the servo pattern 52A is read by the servo reading element SR, the angle between the linear magnetization region 54A1 and the servo reading element SR is different from the angle between the linear magnetization region 54A2 and the servo reading element SR. This difference in angles results in variations in the servo signal originating from the linear magnetization region 54A1 and the servo signal originating from the linear magnetization region 54A2, due to azimuth loss. Such variations in the servo signal can contribute to a decrease in the accuracy of servo control.

Therefore, in light of these circumstances, in this embodiment, as an example, a magnetic tape MT is employed, as shown in Figure 9. The magnetic tape MT differs from the magnetic tape MT0 in that it has a frame 56 instead of a frame 50. The frame 56 is defined by a set of servo patterns 58. Multiple servo patterns 58 are recorded in the servo band SB along the longitudinal direction LD. The multiple servo patterns 58 are arranged at regular intervals along the longitudinal direction LD, similar to the multiple servo patterns 52 recorded on the magnetic tape MT0.

In the example shown in Figure 9, servo patterns 58A and 58B are shown as an example of a pair of servo patterns 58 included in frame 56. Servo patterns 58A and 58B are adjacent to each other along the longitudinal direction LD, with servo pattern 58A located on the upstream side in the forward direction within frame 56, and servo pattern 58B located on the downstream side in the forward direction.

The servo pattern 58 consists of linear magnetization region pairs 60. These linear magnetization region pairs 60 are classified into linear magnetization region pairs 60A and linear magnetization region pairs 60B.

The servo pattern 58A consists of a pair of linear magnetization regions 60A. In the example shown in Figure 9, linear magnetization regions 60A1 and 60A2 are shown as examples of the pair of linear magnetization regions 60A. Each of the linear magnetization regions 60A1 and 60A2 is a linearly magnetized region.

The linear magnetization regions 60A1 and 60A2 are tilted in opposite directions with respect to the virtual line C1. In other words, linear magnetization region 60A1 is tilted in one direction with respect to the virtual line C1 (for example, clockwise when viewed from the front side of the paper in Figure 9). On the other hand, linear magnetization region 60A2 is tilted in the other direction with respect to the virtual line C1 (for example, counterclockwise when viewed from the front side of the paper in Figure 9). The linear magnetization regions 60A1 and 60A2 are nonparallel to each other and are tilted at different angles with respect to the virtual line C1. The tilt angle of linear magnetization region 60A1 with respect to the virtual line C1 is steeper than that of linear magnetization region 60A2. Here, "steep" means, for example, that the angle of linear magnetization region 60A1 with respect to the virtual line C1 is smaller than the angle of linear magnetization region 60A2 with respect to the virtual line C1. Furthermore, the total length of the linear magnetization region 60A1 is shorter than the total length of the linear magnetization region 60A2.

In the servo pattern 58A, the linear magnetization region 60A1 contains multiple magnetization lines 60A1a, and the linear magnetization region 60A2 contains multiple magnetization lines 60A2a. The number of magnetization lines 60A1a contained in the linear magnetization region 60A1 is the same as the number of magnetization lines 60A2a contained in the linear magnetization region 60A2.

A linear magnetization region 60A1 is a collection of five magnetized straight lines, which are magnetization lines 60A1a, and a linear magnetization region 60A2 is a collection of five magnetized straight lines, which are magnetization lines 60A2a. Within the servo band SB, the positions of both ends of the linear magnetization region 60A1 (i.e., the positions of each of the five magnetization lines 60A1a) and the positions of both ends of the linear magnetization region 60A2 (i.e., the positions of each of the five magnetization lines 60A2a) are aligned in the width direction WD. Here, we have given an example where the positions of both ends of each of the five magnetization lines 60A1a and the positions of both ends of each of the five magnetization lines 60A2a are aligned. However, this is merely one example; it is sufficient if the positions of the ends of one or more of the five magnetization lines 60A1a and the positions of the ends of one or more of the five magnetization lines 60A2a are aligned. Furthermore, in this embodiment, the concept of "aligned" includes not only the meaning of perfectly aligned, but also the meaning of "aligned" including errors that are generally acceptable in the art to which this disclosure pertains and do not contradict the spirit of this disclosure.

The servo pattern 58B consists of a pair of linear magnetization regions 60B. In the example shown in Figure 9, linear magnetization regions 60B1 and 60B2 are shown as examples of the pair of linear magnetization regions 60B. Each of the linear magnetization regions 60B1 and 60B2 is a linearly magnetized region.

The linear magnetization regions 60B1 and 60B2 are tilted in opposite directions with respect to the virtual line C2. In other words, linear magnetization region 60B1 is tilted in one direction with respect to the virtual line C2 (for example, clockwise when viewed from the front side of the paper in Figure 9). On the other hand, linear magnetization region 60B2 is tilted in the other direction with respect to the virtual line C2 (for example, counterclockwise when viewed from the front side of the paper in Figure 9). The linear magnetization regions 60B1 and 60B2 are nonparallel to each other and are tilted at different angles with respect to the virtual line C2. The tilt angle of linear magnetization region 60B1 with respect to the virtual line C2 is steeper than that of linear magnetization region 60B2. Here, "steep" means, for example, that the angle of linear magnetization region 60B1 with respect to the virtual line C2 is smaller than the angle of linear magnetization region 60B2 with respect to the virtual line C2. Furthermore, the total length of the linear magnetization region 60B1 is shorter than the total length of the linear magnetization region 60B2.

In the servo pattern 58B, the linear magnetization region 60B1 contains multiple magnetization lines 60B1a, and the linear magnetization region 60B2 contains multiple magnetization lines 60B2a. The number of magnetization lines 60B1a contained in the linear magnetization region 60B1 is the same as the number of magnetization lines 60B2a contained in the linear magnetization region 60B2.

The total number of magnetization lines 60B1a and 60B2a included in servo pattern 58B differs from the total number of magnetization lines 60A1a and 60A2a included in servo pattern 58A. In the example shown in Figure 9, the total number of magnetization lines 60A1a and 60A2a included in servo pattern 58A is 10, while the total number of magnetization lines 60B1a and 60B2a included in servo pattern 58B is 8.

The linear magnetization region 60B1 is a set of four magnetized straight lines, namely magnetization lines 60B1a, and the linear magnetization region 60B2 is a set of four magnetized straight lines, namely magnetization lines 60B2a. Within the servoband SB, the positions of both ends of the linear magnetization region 60B1 (i.e., the positions of each of the four magnetization lines 60B1a) and the positions of both ends of the linear magnetization region 60B2 (i.e., the positions of each of the four magnetization lines 60B2a) are aligned in the width direction WD.

Note that while this example shows the positions of both ends of each of the four magnetization lines 60B1a and the positions of both ends of each of the four magnetization lines 60B2a aligned, this is merely one example. It is sufficient if the positions of both ends of one or more of the four magnetization lines 60B1a and the positions of both ends of one or more of the four magnetization lines 60B2a are aligned.

Furthermore, while examples of linear magnetization regions 60A1, 60B1, 60B2, and 60B2 are given, the technology of this disclosure is not limited to these examples. For example, linear magnetization region 60A1 may consist of a number of magnetization lines 60A1a that contribute to identifying the position of the magnetic head 28 on the magnetic tape MT, linear magnetization region 60A2 may consist of a number of magnetization lines 60A2a that contribute to identifying the position of the magnetic head 28 on the magnetic tape MT, linear magnetization region 60B1 may consist of a number of magnetization lines 60B1a that contribute to identifying the position of the magnetic head 28 on the magnetic tape MT, and linear magnetization region 60B2 may consist of a number of magnetization lines 60B2a that contribute to identifying the position of the magnetic head 28 on the magnetic tape MT.

Here, the geometric characteristics of the linear magnetization region pair 60A on the magnetic tape MT will be explained with reference to Figure 10. In this embodiment, geometric characteristics refer to generally recognized geometric properties such as length, shape, orientation, and/or position.

As an example, as shown in Figure 10, the geometric characteristics of the linear magnetization region pair 60A on the magnetic tape MT can be represented using a virtual linear region pair 62. The virtual linear region pair 62 consists of a virtual linear region 62A and a virtual linear region 62B.

The virtual linear region pair 62 is a hypothetical linear magnetization region pair having the same geometric properties as the linear magnetization region pair 54A shown in Figure 6. The virtual linear region pair 62 is a hypothetical magnetization region used for convenience to explain the geometric properties of the linear magnetization region pair 60A on the magnetic tape MT, and is not an actual existing magnetization region.

The virtual linear region 62A has the same geometric characteristics as the linear magnetization region 54A1 shown in Figure 6, and consists of five virtual lines 62A1 corresponding to the five magnetization lines 54A1a shown in Figure 6. The virtual linear region 62B has the same geometric characteristics as the linear magnetization region 54B1 shown in Figure 6, and consists of five virtual lines 62B1 corresponding to the five magnetization lines 54A2a shown in Figure 6.

A center O1 is provided within the virtual linear region pair 62. For example, center O1 is the center of the line segment L0 connecting the center of the line 62A1 located furthest upstream in the forward direction among the five lines 62A1, and the center of the line 62B1 located furthest downstream in the forward direction among the five lines 62B1.

Since the virtual linear region pair 62 has the same geometric characteristics as the linear magnetization region pair 54A shown in Figure 6, the virtual linear region 62A and the virtual linear region 62B are tilted symmetrically with respect to the virtual line C1. Now, let's consider the case where the entire virtual linear region pair 62 is tilted with respect to the virtual line C1 by tilting the axis of symmetry SA1 of the virtual linear regions 62A and 62B by an angle a (for example, 10 degrees) with respect to the virtual line C1, using the center O1 as the axis of rotation, and then reading is performed on the virtual linear region pair 62 using a servo reading element SR. In this case, within the virtual linear region pair 62, there are areas in the width direction WD where the virtual linear region 62A is read but the virtual linear region 62B is not, or where the virtual linear region 62A is not read but the virtual linear region 62B is read. In other words, when reading is performed by the servo reading element SR in each of the virtual linear regions 62A and 62B, a missing portion and an unnecessary portion will occur.

Therefore, by supplementing the deficient parts and removing the unnecessary parts, the positions of both ends of the virtual linear region 62A (i.e., the positions of each of the five straight lines 62A1) and the positions of both ends of the virtual linear region 62B (i.e., the positions of each of the five straight lines 62B1) are aligned in the width direction WD.

The geometric characteristics of the virtual linear region pair 62 obtained in this way (i.e., the geometric characteristics of the virtual servo pattern) correspond to the geometric characteristics of the actual servo pattern 58A. That is, the servo band SB records the linear magnetization region pair 60A whose geometric characteristics correspond to the geometric characteristics of the virtual linear region pair 62 obtained by aligning the positions of both ends of the virtual linear region 62A with the positions of both ends of the virtual linear region 62B in the width direction WD.

Furthermore, the linear magnetization region pair 60B differs from the linear magnetization region pair 60A only in that it has four magnetization lines 60B1a instead of five magnetization lines 60A1a, and four magnetization lines 60B2a instead of five magnetization lines 604A2a. Therefore, the servo band SB records the linear magnetization region pair 60B, whose geometric characteristics correspond to those of a virtual linear region pair (not shown) obtained by aligning the positions of both ends of the four lines 62A1 with the positions of both ends of the four lines 62B1 in the width direction WD.

As an example, as shown in Figure 11, the magnetic tape MT has multiple servo bands SB formed in the width direction WD. The frames 56 corresponding to each other in the servo bands SB are shifted 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 in the servo bands SB are shifted by a predetermined interval in the longitudinal direction LD between adjacent servo bands SB in the width direction WD.

The default 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 "servo band pitch"), and the frame length. In the example shown in Figure 11, the angle α is exaggerated to make it easier to visually grasp, but in reality, the angle α is, for example, about 15 degrees. The angle α is the angle formed between the frames 56 that do not correspond to each other in the width direction WD between adjacent servo bands SB and the virtual straight line C1. In the example shown in Figure 11, an example of angle α is shown as the angle formed between one frame 56 of a pair of frames 56 corresponding to adjacent servo bands SB in the width direction WD (in the example shown in Figure 11, 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 11, one frame 56 of servo band SB2 that corresponds to one frame 56 of servo band SB3) (in the example shown in Figure 11, line segment L1) and the virtual line C1. In this case, frame length refers to the total length of frame 56 in the longitudinal direction LD. The default interval is defined by the following formula (1). Note that Mod(A/B) means the remainder obtained when "A" is divided by "B".

(Default interval) = Mod{(Servo band pitch × tanα) / (Frame length)} ... (1)

In the example shown in Figure 11, angle α is exemplified as the angle formed between one frame 56 of a pair of frames 56 corresponding to adjacent servo bands SB in the width direction WD (hereinafter also referred to as the "first frame") and the frame 56 adjacent to the other frame 56 of the pair of frames 56 (hereinafter also referred to as the "second frame"), and the virtual line C1. However, the technology of this disclosure is not limited to this. For example, angle α may be the angle formed between the first corresponding frame and a frame 56 located two or more frames away from the second frame within the same servo band SB as the second frame (hereinafter also referred to as the "third frame"), and the virtual line C1. In this case, the "frame length" used in formula (1) is the pitch between the second frame and the third frame in the longitudinal direction LD (for example, the distance from the tip of the second frame to the tip of the third frame).

As an example, as shown in Figure 12, when the servo pattern 58A (i.e., the linear magnetization region pair 60A) is read by the servo reading element SR when the direction of virtual line C1 and the direction of virtual line C3 coincide (i.e., the longitudinal direction and width direction WD of the magnetic head 28 coincide), variations due to azimuth loss occur between the servo signal originating from linear magnetization region 60A1 and the servo signal originating from linear magnetization region 60A2. Similarly, when the servo pattern 58B (i.e., the linear magnetization region pair 60B) is read by the servo reading element SR when the direction of virtual line C1 and the direction of virtual line C3 coincide (i.e., the longitudinal direction and width direction WD of the magnetic head 28 coincide), the same phenomenon occurs.

Therefore, as an example shown in Figure 13, the tilting mechanism 49 (see Figure 8) skews the magnetic head 28 on the magnetic tape MT around the rotation axis RA such that the virtual line C3 is tilted at an angle β (i.e., a counterclockwise angle β when viewed from the front side of the paper in Figure 13) relative to the virtual line C1. Because the magnetic head 28 is tilted at an angle β towards the upstream side in the forward direction on the magnetic tape MT, the variation due to azimuth loss between the servo signal originating from the linear magnetization region 60A1 and the servo signal originating from the linear magnetization region 60A2 is reduced compared to the example shown in Figure 12. Similarly, when the servo pattern 58B (i.e., the linear magnetization region pair 60B) is read by the servo reading element SR, the variation due to azimuth loss between the servo signal originating from the linear magnetization region 60B1 and the servo signal originating from the linear magnetization region 60B2 is also reduced.

Here, angle β is set to coincide with angle a (see Figure 10), which is the angle obtained by rotating the axis of symmetry SA1 (see Figure 10) of the virtual linear regions 62A and 62B (see Figure 10) with respect to the virtual straight line C1, with the center O1 (see Figure 10) as the axis of rotation. In this embodiment, "coincidence" refers not only to a perfect coincidence but also to an error that is generally acceptable in the art to which the present disclosure belongs and does not contradict the spirit of the present disclosure. The geometric properties of the virtual linear regions 62A and 62B are the same as the geometric properties of the linear magnetization regions 60A1 and 60B1. Therefore, the linear magnetization regions 60A1 and 60B1 are also inclined at angle a with respect to the virtual straight line C1. In this case, when the magnetic head 28 is tilted upstream in the forward direction by an angle β (i.e., angle a) on the magnetic tape MT, the tilt angle of the magnetic head 28 matches the tilt angles of the linear magnetization regions 60A1 and 60A2. As a result, the variation due to azimuth loss between the servo signal originating from linear magnetization region 60A1 and the servo signal originating from linear magnetization region 60A2 is reduced. Similarly, when the servo pattern 58B (i.e., the linear magnetization region pair 60B) is read by the servo reading element SR, the variation due to azimuth loss between the servo signal originating from linear magnetization region 60B1 and the servo signal originating from linear magnetization region 60B2 is also reduced.

As an example, as shown in Figure 14, the control device 30 includes a control unit 30A and a position detection unit 30B. The position detection unit 30B includes a first position detection unit 30B1 and a second position detection unit 30B2. The position detection unit 30B acquires a servo signal, which is the result of reading the servo pattern 58 by the servo reading element SR, and detects the position of the magnetic head 28 on the magnetic tape MT based on the acquired servo signal.

The servo signals are classified into a first servo signal and a second servo signal. The first servo signal is the servo signal resulting from the reading of the servo pattern 58 by the servo reading element SR1, and the second servo signal is the servo signal resulting from the reading of the servo pattern 58 by the servo reading element SR2.

The first position detection unit 30B1 acquires the first servo signal, and the second position detection unit 30B2 acquires the second servo signal. In the example shown in Figure 14, the first position detection unit 30B1 acquires the first servo signal obtained by reading the servo pattern 58 in the servo band SB2 using the servo reading element SR1, and the second position detection unit 30B2 acquires the second servo signal obtained by reading the servo pattern 58 in the servo band SB3 using the servo reading element SR2. Based on the first servo signal, the first position detection unit 30B1 detects the position of the servo reading element SR1 relative to the servo band SB2, and based on the second servo signal, the second position detection unit 30B2 detects the position of the servo reading element SR2 relative to the servo band SB3.

The control unit 30A performs various controls based on the position detection results from the first position detection unit 30B1 (i.e., the position detected by the first position detection unit 30B1) and the position detection results from the second position detection unit 30B2 (i.e., the position detected by the second position detection unit 30B2). Here, various controls refer to, for example, servo control, skew angle control, and/or tension control. Tension control refers to the control of the tension applied to the magnetic tape MT (for example, tension to reduce the effect of TDS).

As an example, as shown in Figure 15, the position detection unit 30B detects the servo signal, which is the result of reading the servo pattern 58 from the magnetic tape MT by the servo reading element SR, using the autocorrelation coefficient.

The storage 32 stores the ideal waveform signal 66. The ideal waveform signal 66 is a signal representing a single ideal waveform included in the servo signal (for example, an ideal signal resulting from the reading of one ideal magnetization line included in the servo pattern 58 by the servo reading element SR). The ideal waveform signal 66 can also be considered a sample signal compared to the servo signal. While this example shows the ideal waveform signal 66 stored in the storage 32, this is merely one example. For example, the ideal waveform signal 66 may be stored in the cartridge memory 24 instead of, or together with, the storage 32. Furthermore, the ideal waveform signal 66 may be recorded in the BOT area (not shown) at the beginning of the magnetic tape MT, and/or in the EOT area (not shown) at the end of the magnetic tape MT.

The autocorrelation coefficient used by the position detection unit 30B is a coefficient that indicates the degree of correlation between the servo signal and the ideal waveform signal 66. The position detection unit 30B acquires the ideal waveform signal 66 from the storage 32 and compares the acquired ideal waveform signal 66 with the servo signal. Then, the position detection unit 30B calculates the autocorrelation coefficient based on the comparison result. The position detection 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 coincide) according to the autocorrelation coefficient.

The position of the servo reading element SR relative to the servo band SB is detected, for example, as follows. The autocorrelation coefficient makes it possible to detect the spacing of the longitudinal LDs of the servo patterns 58A and 58B. For example, when the servo reading element SR is located on the upper side of the servo pattern 58 (i.e., the upper side in the front view of the paper in Figure 14), the spacing between linear magnetization regions 60A1 and 60A2 becomes narrower, and the spacing between linear magnetization regions 60B1 and 60B2 also becomes narrower. In contrast, when the servo reading element SR is located on the lower side of the servo pattern 58 (i.e., the lower side in the front view of the paper in Figure 14), the spacing between linear magnetization regions 60A1 and 60A2 becomes wider, and the spacing between linear magnetization regions 60B1 and 60B2 also becomes wider. In this way, the position detection unit 30B detects the position of the servo reading element SR relative to the servo band SB using the distance between linear magnetization regions 60A1 and 60A2, and the distance between linear magnetization regions 60B1 and 60B2, which are 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 from the position detection unit 30B (i.e., the position detected by the position detection unit 30B). Furthermore, the control unit 30A causes the magnetic element unit 42 to perform magnetic processing on the data band DB of the magnetic tape MT. That is, the control unit 30A acquires a reading signal (data read from the data band DB of the magnetic tape MT by the magnetic element unit 42) from the magnetic element unit 42, or supplies a recording signal to the magnetic element unit 42 to record data corresponding to the recording signal on the data band DB of the magnetic tape MT.

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 30B, and performs tension control or skews the magnetic head 28 on the magnetic tape MT according to the calculated servo band pitch. Tension control is achieved by adjusting the rotational speed and rotational torque of the feed motor 36 and the winding motor 40, respectively. Skew of the magnetic head 28 is achieved by activating the tilting mechanism 49.

Next, we will describe an example of two processes included in the manufacturing process of magnetic tape MT: the servo pattern recording process, which records a servo pattern 58 on the servo band SB of the magnetic tape MT, and the winding process, which winds the magnetic tape MT.

As an example, as shown in Figure 16, a servo writer SW is used in the servo pattern recording process. The servo writer SW comprises a feed reel SW1, a take-up reel SW2, a drive unit SW3, a pulse signal generator SW4, a control unit SW5, multiple guide SW6, a transport path SW7, a servo pattern recording head WH, and a verify head VH.

In this embodiment, the servo writer SW is an example of a "servo pattern recording device" and "inspection device" according to the technology of this disclosure. Furthermore, in this embodiment, the pulse signal generator SW4 is an example of a "pulse signal generator" according to the technology of this disclosure. Furthermore, in this embodiment, the servo pattern recording head WH is an example of a "servo pattern recording head" according to the technology of this disclosure. Furthermore, in this embodiment, the control device SW5 is an example of an "inspection processor" according to the technology of this disclosure.

The control device SW5 controls the entire servowriter SW. In this embodiment, the control device SW5 is implemented by an ASIC, but the technology of this disclosure is not limited thereto. For example, the control device SW5 may be implemented by an FPGA and/or PLC. Alternatively, the control device SW5 may be implemented by a computer including a CPU, flash memory (e.g., EEPROM and/or SSD), and RAM. Furthermore, it may be implemented by a combination of two or more of the ASIC, FPGA, PLC, and computer. In other words, the control device SW5 may be implemented by a combination of hardware and software configurations.

The delivery reel SW1 is equipped with a pancake. A pancake refers to a large-diameter roll on which magnetic tape MT, cut to the product width from a wide web base before the servo pattern 58 is written, is wound around a hub.

The drive unit SW3 has a motor (not shown) and gears (not shown) and is mechanically connected to the delivery reel SW1 and the take-up reel SW2. When the magnetic tape MT is wound up by the take-up reel SW2, the drive unit SW3 generates power according to instructions from the control device SW5 and transmits the generated power to the delivery reel SW1 and the take-up reel SW2, thereby rotating them. That is, the delivery reel SW1 rotates by receiving power from the drive unit SW3 and sends the magnetic tape MT to the predetermined transport path SW7. The take-up reel SW2 rotates by receiving power from the drive unit SW3 and winds up the magnetic tape MT sent up from the delivery reel SW1. The rotational speed and rotational torque of the delivery reel SW1 and the take-up reel SW2 are adjusted according to the speed at which the magnetic tape MT is wound up by the take-up reel SW2.

Multiple guide switches (SW6) and a servo pattern recording head (WH) are arranged on the transport path (SW7). The servo pattern recording head (WH) is positioned between the multiple guide switches (SW6) on the surface (31) side of the magnetic tape (MT). The magnetic tape (MT), fed from the delivery reel (SW1) onto the transport path (SW7), is guided by the multiple guide switches (SW6), passes over the servo pattern recording head (WH), and is then wound up by the take-up reel (SW2).

The manufacturing process for magnetic tape (MT) includes several steps in addition to the servo pattern recording process. These steps include inspection and winding processes.

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

The inspection process is performed using the control device SW5 and the verify head VH. The verify head VH is positioned downstream of the servo pattern recording head WH in the transport direction of the magnetic tape MT. Furthermore, the verify head VH, like the magnetic head 28, is equipped with multiple servo reading elements (not shown), and readings are performed for multiple servo bands SB using these multiple servo reading elements. In addition, the verify head VH, like the magnetic head 28, is skewed on the surface 31 of the magnetic tape MT.

The verify head VH is connected to the control device SW5. The verify head VH is positioned to face the servo band SB directly when viewed from the surface 31 side of the magnetic tape MT (i.e., the back side of the verify head VH). It reads the servo pattern 58 recorded on the servo band SB and outputs the reading result (hereinafter referred to as "servo pattern reading result") to the control device SW5. The control device SW5 performs an inspection of the servo band SB (e.g., determination of the correctness of the servo pattern 58) based on the servo pattern reading result (e.g., servo signal) input from the verify head VH. For example, the control device SW5 operates as the position detection unit 30B shown in Figure 14 to obtain a position detection result from the servo pattern reading result, and performs the inspection of the servo band SB by determining the correctness of the servo pattern 58 using the position detection result.

The control device SW5 outputs information indicating the result of inspecting the servo band SB (for example, the result of determining whether the servo pattern 58 is correct or incorrect) to a predetermined output destination (for example, storage 32 (see Figure 3), UI system device 34 (see Figure 3), and/or external device 37 (see Figure 3), etc.).

For example, once the inspection process is complete, the winding process is performed. The winding process involves winding the magnetic tape MT onto a delivery reel 22 used for each of the multiple magnetic tape cartridges 12 (see Figures 1 to 4) (i.e., the delivery reels 22 housed in the magnetic tape cartridges 12 (see Figures 1 to 4) (see Figures 2 to 4)). A winding motor M is used in the winding process. The winding motor M is mechanically connected to the delivery reel 22 via gears or the like. Under the control of a control device (not shown), the winding motor M rotates the delivery reel 22 by applying rotational force to it. The magnetic tape MT wound onto the winding reel SW2 is then wound onto the delivery reel 22 by the rotation of the delivery reel 22. A cutting device (not shown) is used in the winding process. For each of the multiple feed reels 22, once the required amount of magnetic tape MT has been wound onto the feed reel 22, the magnetic tape MT being fed from the take-up reel SW2 to the feed reel 22 is cut by the cutting device.

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

Figure 17 shows an example of the configuration of the servo pattern recording head WH and an example of the configuration of the pulse signal generator SW4, when the servo pattern recording head WH is observed from the surface 31 side (i.e., the back side of the servo pattern recording head WH) of the magnetic tape MT traveling on the transport path SW7 (see Figure 16).

As an example, as shown in Figure 17, the servo pattern recording head WH has a base body WH1 and a plurality of head cores WH2. The base body WH1 is formed in a rectangular parallelepiped shape and is arranged to traverse the surface 31 of the magnetic tape MT, which travels along the transport path SW7, along the width direction WD. The surface WH1A of the base body WH1 is a rectangle with a long side WH1Aa and a short side WH1Ab. The longitudinal direction of the base body WH1, i.e., the long side WH1Aa, is inclined with respect to the direction WD1 corresponding to the width direction WD (for example, the same direction as the width direction WD). Furthermore, the base body WH1 traverses the magnetic tape MT diagonally. That is, the long side WH1Aa traverses the surface 31 of the magnetic tape MT diagonally from one end to the other of the magnetic tape MT's width.

The surface WH1A has a sliding surface WH1Ax. The sliding surface WH1Ax is the surface of the surface WH1A that overlaps with the surface 31 of the magnetic tape MT when the base body WH1 is diagonally traversing the surface 31 of the magnetic tape MT along the width direction WD (for example, the dot-shaped hatched area shown in Figure 17), and slides against the magnetic tape MT in its running state. The width of the sliding surface WH1Ax shown in Figure 17 (i.e., the length of the short side WH1Ab) is merely an example; the width of the sliding surface WH1Ax may be several times wider than the example shown in Figure 17.

Multiple head cores WH2 are incorporated into the substrate WH1 along the direction of the long side WH1Aa. A gap pattern G is formed on the head cores WH2. The gap pattern G is formed on the surface WH1A (i.e., the side of the substrate WH1 facing the surface 31 of the magnetic tape MT). The gap pattern G consists of a pair of non-parallel linear regions. These non-parallel linear regions refer, for example, to a linear region with the same geometric characteristics as the magnetization line 60A1a located on the upstreammost side in the forward direction among the five magnetization lines 60A1a included in the linear magnetization region 60A1 shown in Figure 9, and to a linear region with the same geometric characteristics as the magnetization line 60A2a located on the upstreammost side in the forward direction among the five magnetization lines 60A2a included in the linear magnetization region 60A2 shown in Figure 9.

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

A coil (not shown) is wound around the head core WH2, and pulse signals are supplied to the coil. The pulse signals supplied to the coil are for servo pattern 58A and for servo pattern 58B.

When the gap pattern G is directly facing the servo band SB of the magnetic tape MT traveling on the transport path SW7, a pulse signal for servo pattern 58A is supplied to the coil of the head core WH2. A magnetic field is then applied from the gap pattern G to the servo band SB of the magnetic tape MT according to the pulse signal. As a result, servo pattern 58A is recorded on the servo band SB. Similarly, when the gap pattern G is directly facing the servo band SB of the magnetic tape MT traveling on the transport path SW7, a pulse signal for servo pattern 58B is supplied to the coil of the head core WH2. A magnetic field is then applied from the gap pattern G to the servo band SB of the magnetic tape MT. As a result, servo pattern 58B is recorded on the servo band SB.

The pulse signals corresponding to each servo pattern 58 (i.e., each servo pattern 58 in each frame 56 (see Figure 9)) are modulated. Modulation of the pulse signals embeds various information into them. In this case, for example, by modulating the pulse signal for servo pattern 58A, it becomes possible to change the interval between the third and second magnetization lines 60A1a (hereinafter referred to as the "first interval") and the interval between the third and fourth magnetization lines 60A1a (hereinafter referred to as the "second interval") for each servo pattern 58A. By varying the first and second intervals for each servo pattern 58A, it becomes possible to embed at least one bit of information into each individual servo pattern 58A. This makes it possible to embed various information by combining multiple servo patterns 58.

The various pieces of information may include, for example, information regarding the position of the longitudinal LD, information identifying the servo band SB, and/or information identifying the manufacturer of the magnetic tape MT, etc., and in this case, it also refers to the pulse signal.

In the example shown in Figure 17, head cores WH2A, WH2B, and WH2C are shown as examples of multiple head cores WH2, and gap patterns G1, G2, and G3 are shown as examples of multiple gap patterns G. Gap pattern G1 is formed on head core WH2A. Gap pattern G2 is formed on head core WH2B. Gap pattern G3 is formed on head core WH2C.

Each of the gap patterns G1 to G3 has the same geometric characteristics. In this embodiment, for example, gap pattern G1 is used to record the servo pattern 58 (see Figure 9) for servo band SB3 (see Figure 9), gap pattern G2 is used to record the servo pattern 58 (see Figure 9) for servo band SB2 (see Figure 9), and gap pattern G3 is used to record the servo pattern 58 (see Figure 9) for servo band SB1 (see Figure 9).

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.

In this embodiment, the pair of linear regions G1A and G1B, the pair of linear regions G2A and G2B, and the pair of linear regions G3A and G3B are examples of "pairs of linear regions" according to the technology of this disclosure. Furthermore, in this embodiment, linear regions G1A, G2A, and G3A are examples of "first linear regions" according to the technology of this disclosure. Furthermore, in this embodiment, linear regions G1B, G2B, and G3B are examples of "second linear regions" according to the technology of this disclosure.

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

When gap pattern G1 is used for servo band SB3 (see Figure 9), the first pulse signal generator SW4A supplies a pulse signal to the head core WH2A. According to the pulse signal, a magnetic field is applied from gap pattern G1 to servo band SB3, and servo pattern 58 (see Figure 9) is recorded on servo band SB3.

For example, when the gap pattern G1 is directly facing the servo band SB3 of a magnetic tape MT traveling on the transport path SW7, and a pulse signal for the servo pattern 58A is supplied to the head core WH2A, the servo pattern 58A (see Figure 9) is recorded on the servo band SB3. That is, a linear magnetization region 60A1 (see Figure 9) is recorded on the servo band SB3 by the linear region G1A, and a linear magnetization region 60A2 (see Figure 9) is recorded on the servo band SB3 by the linear region G1B.

Furthermore, for example, when the gap pattern G1 is directly facing the servo band SB3 of the magnetic tape MT traveling on the transport path SW7, and a pulse signal for the servo pattern 58B is supplied to the head core WH2A, the servo pattern 58B (see Figure 9) is recorded on the servo band SB3. That is, a linear magnetization region 60B1 (see Figure 9) is recorded on the servo band SB3 by the linear region G1A, and a linear magnetization region 60B2 (see Figure 9) is recorded on the servo band SB3 by the linear region G1B.

When gap pattern G2 is used for servo band SB2 (see Figure 9), the second pulse signal generator SW4B supplies a pulse signal to the head core WH2B. According to the pulse signal, a magnetic field is applied from gap pattern G2 to servo band SB2, and the servo pattern 58 is recorded in servo band SB2.

For example, when the gap pattern G2 is directly facing the servo band SB2 of a magnetic tape MT traveling on the transport path SW7, and a pulse signal for the servo pattern 58A is supplied to the head core WH2B, the servo pattern 58A (see Figure 9) is recorded on the servo band SB2. That is, a linear magnetization region 60A1 is recorded on the servo band SB2 by the linear region G2A, and a linear magnetization region 60A2 is recorded on the servo band SB2 by the linear region G2B.

Furthermore, for example, when the gap pattern G2 is directly facing the servo band SB2 of the magnetic tape MT traveling on the transport path SW7, and a pulse signal for the servo pattern 58B is supplied to the head core WH2B, the servo pattern 58B is recorded on the servo band SB2. That is, a linear magnetization region 60B1 is recorded on the servo band SB2 by the linear region G2A, and a linear magnetization region 60B2 is recorded on the servo band SB2 by the linear region G2B.

When gap pattern G3 is used for servo band SB1 (see Figure 9), the third pulse signal generator SW4C supplies a pulse signal to the head core WH2C. According to the pulse signal, a magnetic field is applied from gap pattern G3 to servo band SB1, and servo pattern 58 is recorded on servo band SB1.

For example, when the gap pattern G3 is directly facing the servo band SB1 of a magnetic tape MT traveling on the transport path SW7, and a pulse signal for the servo pattern 58A is supplied to the head core WH2C, the servo pattern 58A is recorded on the servo band SB1. That is, a linear magnetization region 60A1 is recorded on the servo band SB1 by the linear region G3A, and a linear magnetization region 60A2 is recorded on the servo band SB1 by the linear region G3B.

Furthermore, for example, when the gap pattern G3 is directly facing the servo band SB1 of the magnetic tape MT traveling on the transport path SW7, and a pulse signal for the servo pattern 58B is supplied to the head core WH2C, the servo pattern 58B is recorded on the servo band SB1. That is, a linear magnetization region 60B1 is recorded on the servo band SB1 by the linear region G3A, and a linear magnetization region 60B2 is recorded on the servo band SB1 by the linear region G3B.

As an example, as shown in Figure 18, in the gap pattern G1, the linear regions G1A and G1B are inclined in directions opposite to the line along direction WD1, i.e., the virtual line C1. In other words, linear region G1A is inclined in one direction with respect to the virtual line C1 (for example, clockwise when viewed from the front side of the paper in Figure 18). On the other hand, linear region G1B is inclined in the other direction with respect to the virtual line C1 (for example, counterclockwise when viewed from the front side of the paper in Figure 18). Furthermore, the angle of inclination of linear region G1A with respect to the virtual line C1 is steeper than that of linear region G1B. Here, "steep" means, for example, that the angle of linear region G1A with respect to the virtual line C1 is smaller than the angle of linear region G1B with respect to the virtual line C1. Also, the positions of both ends of linear region G1A and the positions of both ends of linear region G1B are aligned in direction WD1. Furthermore, the total length of linear region G1A is shorter than the total length of linear region G1B.

In gap pattern G2, linear regions G2A and G2B are inclined in opposite directions with respect to the virtual line C1. In other words, linear region G2A is inclined in one direction with respect to the virtual line C1 (for example, clockwise when viewed from the front side of the paper in Figure 18). On the other hand, linear region G2B is inclined in the other direction with respect to the virtual line C1 (for example, counterclockwise when viewed from the front side of the paper in Figure 18). Furthermore, the angle of inclination of linear region G2A with respect to the virtual line C1 is steeper than that of linear region G2B. Here, "steep" means, for example, that the angle of linear region G2A with respect to the virtual line C1 is smaller than the angle of linear region G2B with respect to the virtual line C1. Also, the positions of both ends of linear region G2A and the positions of both ends of linear region G2B are aligned in direction WD1. Finally, the total length of linear region G2A is shorter than the total length of linear region G2B.

In gap pattern G3, linear regions G3A and G3B are inclined in opposite directions with respect to the virtual line C1. In other words, linear region G3A is inclined in one direction with respect to the virtual line C1 (for example, clockwise when viewed from the front side of the paper in Figure 18). On the other hand, linear region G3B is inclined in the other direction with respect to the virtual line C1 (for example, counterclockwise when viewed from the front side of the paper in Figure 18). Furthermore, the angle of inclination of linear region G3A with respect to the virtual line C1 is steeper than that of linear region G3B. Here, "steep" means, for example, that the angle of linear region G3A with respect to the virtual line C1 is smaller than the angle of linear region G3B with respect to the virtual line C1. Also, the positions of both ends of linear region G3A and the positions of both ends of linear region G3B are aligned in direction WD1. Furthermore, the total length of linear region G3A is shorter than the total length of linear region G3B.

Gap patterns G1, G2, and G3 are offset along direction WD1 from adjacent gap patterns G by the predetermined interval described above (i.e., the predetermined interval calculated from formula (1)) in the direction LD1 corresponding to the longitudinal direction LD (for example, the same direction as the longitudinal direction LD).

On surface WH1A, the longer side WH1Aa is longer than the width of the magnetic tape MT. The shorter side WH1Ab is long enough to accommodate all of the gap patterns G1, G2, and G3. The base body WH1 is positioned on the surface 31 side of the magnetic tape MT with the multiple gap patterns G and the surface 31 facing each other, and is tilted along the magnetic tape MT at an angle γ that absorbs a predetermined misalignment. The angle γ that absorbs the misalignment refers to, for example, the amount of rotation equivalent to the amount that at least the gap patterns G1 to G3 are misaligned along direction LD1 from gap pattern G1 to gap pattern G3, and the angle at which the base body WH1 is rotated around its planar center point (i.e., the center point of the base body WH when viewed from the surface 31 side of the magnetic tape MT). Here, the direction in which the base WH1 is rotated around its central point in plan view is counterclockwise when the base WH1 is viewed from the surface 31 side of the magnetic tape MT (i.e., counterclockwise when viewed from the front side of the paper in Figure 18). In the example shown in Figure 18, the extension line C5 of the long side WH1Aa is inclined at an angle γ with respect to the virtual straight line C1.

The pulse signals used between gap patterns G1, G2, and G3 (i.e., the pulse signals supplied from the first pulse signal generator SW4A to the head core WH2A, the pulse signals supplied from the second pulse signal generator SW4B to the head core WH2B, and the pulse signals supplied from the third pulse signal generator SW4C to the head core WH2C, as shown in Figure 17) are in phase.

In the servo pattern recording process, the magnetic tape MT travels along the transport path SW7 at a constant speed with the position of gap pattern G1 corresponding to the position of servo band SB3, the position of gap pattern G2 corresponding to the position of servo band SB2, and the position of gap pattern G3 corresponding to the position of servo band SB1. In this state, pulse signals for servo pattern 58A and pulse signals for servo pattern 58B are alternately supplied to head cores WH2A, WH2B, and WH2C.

When pulse signals for servo pattern 58A are supplied to head cores WH2A, WH2B, and WH2C in phase, servo pattern 58A is recorded on servo bands SB3, SB2, and SB1 with a predetermined interval shift in the longitudinal direction LD. Similarly, when pulse signals for servo pattern 58B are supplied to head cores WH2A, WH2B, and WH2C in phase, servo pattern 58B is recorded on servo bands SB3, SB2, and SB1 with a predetermined interval shift in the longitudinal direction LD.

Here, the geometric properties of the gap pattern G on the surface WH1A will be explained with reference to Figure 19.

As an example, as shown in Figure 19, the geometric properties on the surface WH1A of the gap pattern G can be represented using a pair of virtual linear regions 68. The pair of virtual linear regions 68 consists of virtual linear region 68A and virtual linear region 68B. In this embodiment, the pair of virtual linear regions 68 is an example of a "pair of virtual linear regions" relating to the technology of this disclosure, virtual linear region 68A is an example of "one virtual linear region" relating to the technology of this disclosure, and virtual linear region 68B is an example of "the other virtual linear region" relating to the technology of this disclosure.

The virtual linear region pair 68 is a hypothetical linear region pair having the same geometric properties as the gap pattern G shown in Figure 18. The virtual linear region pair 68 is a hypothetical linear region pair used for convenience to explain the geometric properties on the surface WH1A of the gap pattern G, and is not a real linear region pair.

In this embodiment, for example, the virtual linear region 68A has the same geometric characteristics as the linear region G1A shown in Figure 18, and the virtual linear region 68B has the same geometric characteristics as the linear region G1B shown in Figure 18.

A center O2 is provided within the virtual linear region 68. For example, center O2 is the center of the line segment L2 connecting the center of virtual linear region 68A and the center of virtual linear region 68B.

The virtual linear regions 68A and 68B are tilted symmetrically with respect to the virtual line C1. Here, when the entire pair of virtual linear regions 68 is tilted with respect to the virtual line C1 by tilting the axis of symmetry SA2 of the virtual linear regions 68A and 68B by an angle b (for example, 10 degrees) with respect to the virtual line C1, using the center O2 as the axis of rotation, a comparison is made between the pair of virtual linear regions 68 and the pair of virtual linear regions 62 shown in Figure 10. The pair of virtual linear regions 68 will have both a deficient and an unnecessary portion. Here, the deficient portion refers to the portion that is insufficient for the servo pattern recording head WH to record the servo pattern 58 on the magnetic tape MT, and the unnecessary portion refers to the portion that is unnecessary for the servo pattern recording head WH to record the servo pattern 58 on the magnetic tape MT. The example shown in Figure 19 illustrates a configuration in which the virtual linear region 68B has both a deficient and an unnecessary portion.

Therefore, by supplementing the deficient parts and removing the unnecessary parts, the positions of both ends of the virtual linear region 68A and the positions of both ends of the virtual linear region 68B are aligned with respect to direction WD1.

The geometric properties of the virtual linear region pair 68 obtained in this way (i.e., the geometric properties of the virtual gap pattern) correspond to the geometric properties of the actual gap pattern G. That is, on the surface WH1A (see Figure 18), a gap pattern G is formed with geometric properties corresponding to the geometric properties of the virtual linear region pair 68 obtained by aligning the positions of both ends of the virtual linear region 68A with respect to the direction WD1.

Next, the operation of the magnetic tape system 10 will be explained.

The magnetic tape cartridge 12 contains the magnetic tape MT shown in Figure 9 (see Figures 9 and 11). The magnetic tape cartridge 12 is loaded into the magnetic tape drive 14. When magnetic processing is performed on the magnetic tape MT by the magnetic element unit 42 (see Figures 3 and 15) in the magnetic tape drive 14, the magnetic tape MT is pulled out of the magnetic tape cartridge 12, and the servo pattern 58 within the servo band SB is read by the servo reading element SR of the magnetic head 28.

As shown in Figures 9 and 10, the linear magnetization regions 60A1 and 60A2 included in the servo pattern 58A recorded on the servo band SB of the magnetic tape MT are tilted in directions opposite to the virtual straight line C1. On the other hand, as shown in Figure 13, the magnetic head 28 on the magnetic tape MT is also tilted by an angle β towards the upstream side in the forward direction (i.e., an angle β counterclockwise when viewed from the front side of the paper in Figure 13). In this state, when the servo pattern 58A is read by the servo reading element SR, the angle between the linear magnetization region 60A1 and the servo reading element SR becomes close to the angle between the linear magnetization region 60A2 and the servo reading element SR. Therefore, the variation in the servo signal due to azimuth loss is less than the variation that occurs between the servo signal originating from the linear magnetization region 54A1 included in the conventionally known servo pattern 52A and the servo signal originating from the linear magnetization region 54A2 included in the conventionally known servo pattern 52A.

As a result, the variation between the servo signal originating from linear magnetization region 60A1 and the servo signal originating from linear magnetization region 60A2 is smaller than the variation between the servo signal originating from linear magnetization region 54A1 and the servo signal originating from linear magnetization region 54A2 in the conventionally known servo pattern 52A. This allows for the acquisition of a more reliable servo signal than that obtained from the conventionally known servo pattern 52A (hereinafter, this effect will also be referred to as the "first effect"). Furthermore, as shown in Figure 13, when the magnetic head 28 is tilted at an angle β towards the upstream side in the forward direction on the magnetic tape MT (i.e., an angle β counterclockwise when viewed from the front side of the paper in Figure 13), and the servo pattern 58B is read by the servo reading element SR, the same effect as the first effect (hereinafter, this effect will also be referred to as the "second effect") is obtained.

Incidentally, if the positions of both ends of the linear magnetization region 60A1 and the positions of both ends of the linear magnetization region 60A2 are not aligned in the width direction WD, the servo reading element SR may read one end of the linear magnetization region 60A1 but not one end of the linear magnetization region 60A2, or the servo reading element SR may read the other end of the linear magnetization region 60A1 but not the other end of the linear magnetization region 60A2.

Therefore, in the magnetic tape MT according to this embodiment, the positions of both ends of the linear magnetization region 60A1 (i.e., the positions of both ends of each of the five magnetization lines 60A1a) and the positions of both ends of the linear magnetization region 60A2 (i.e., the positions of both ends of each of the five magnetization lines 60A2a) are aligned in the width direction WD within the servo band SB. Consequently, when reading is performed by the servo reading element SR on the servo pattern 58A, the servo reading element SR can read the linear magnetization regions 60A1 and 60A2 without excess or deficiency, compared to the case where the positions of both ends of the linear magnetization region 60A1 and the positions of both ends of the linear magnetization region 60A2 are not aligned in the width direction WD. As a result, a more reliable servo signal can be obtained compared to the case where the positions of both ends of the linear magnetization region 60A1 and the positions of both ends of the linear magnetization region 60A2 are not aligned in the width direction WD (hereinafter, this effect will be referred to as the "third effect"). Furthermore, when reading is performed on the servo pattern 58B using the servo reading element SR, the same effect as the third effect (hereinafter referred to as the "fourth effect") can be obtained.

As shown in Figures 9 and 10, even though the gradient of the linear magnetization region 60A1 with respect to the virtual straight line C1 is steeper than the gradient of the linear magnetization region 60A2 with respect to the virtual straight line C1, if the total length of the linear magnetization region 60A1 is made longer than the total length of the linear magnetization region 60A2, portions will be read and unreadable between the linear magnetization region 60A1 and the linear magnetization region 60A2 by the servo reading element SR. Similarly, even if the total length of the linear magnetization region 60B1 is made longer than the total length of the linear magnetization region 60B2, portions will be read and unreadable between the linear magnetization region 60B1 and the linear magnetization region 60B2 by the servo reading element SR. Therefore, in the magnetic tape MT according to this embodiment, the total length of the linear magnetization region 60A1 is shorter than the total length of the linear magnetization region 60A2, and the total length of the linear magnetization region 60B1 is shorter than the total length of the linear magnetization region 60B2. This allows for reading of the linear magnetization regions 60A1 and 60A2 by the servo reading element SR, and reading of the linear magnetization regions 60B1 and 60B2 by the servo reading element SR, without any excess or deficiency (hereinafter, this effect will be referred to as the "fifth effect").

Furthermore, in the magnetic tape MT according to this embodiment, the linear magnetization region 60A1 is a collection of five magnetization lines 60A1a, the linear magnetization region 60A2 is a collection of five magnetization lines 60A2a, the linear magnetization region 60B1 is a collection of four magnetization lines 60B1a, and the linear magnetization region 60B2 is a collection of four magnetization lines 60B2a. Therefore, compared to the case where each linear magnetization region consists of a single magnetization line, the amount of information obtained from the servo pattern 58 can be increased, resulting in highly accurate servo control (hereinafter, this effect will be referred to as the "sixth effect").

Furthermore, in the magnetic tape MT according to this embodiment, the geometric characteristics of the linear magnetization region pair 60A on the magnetic tape MT correspond to the geometric characteristics obtained when the entire virtual linear region pair 62 is tilted with respect to the virtual line C1 by tilting the symmetry axis SA1 of the virtual linear region pair 62 with respect to the virtual line C1, thereby aligning the positions of both ends of the virtual linear region 62A and the positions of both ends of the virtual linear region 62B in the width direction WD. Therefore, compared to the case where reading is performed by the servo reading element SR on a servo pattern 52A having conventionally known geometric characteristics, the variation between the servo signal originating from the linear magnetization region 60A1 and the servo signal originating from the linear magnetization region 60A2 can be reduced. As a result, a more reliable servo signal can be obtained than the servo signal obtained from a servo pattern 52A having conventionally known geometric characteristics (hereinafter, this effect will be referred to as the "seventh effect").

The linear magnetization region pair 60B differs from the linear magnetization region pair 60A only in that it has a linear magnetization region 60B1 instead of linear magnetization region 60A1, and a linear magnetization region 60B2 instead of linear magnetization region 60A2. Reading is performed on the linear magnetization region pair 60B in the same way as on the linear magnetization region pair 60A using the servo reading element SR. Therefore, compared to the case where reading is performed on a servo pattern 52B with conventionally known geometric characteristics using the servo reading element SR, the variation between the servo signal originating from linear magnetization region 60B1 and the servo signal originating from linear magnetization region 60B2 can be reduced. As a result, a more reliable servo signal can be obtained than the servo signal obtained from a servo pattern 52B with conventionally known geometric characteristics (hereinafter, this effect will be referred to as the "eighth effect").

In this embodiment, a pair of corresponding servo patterns 58 between servo bands SB are read by servo reading elements SR1 and SR2 included in the magnetic head 28. Furthermore, in this embodiment, the magnetic head 28 is used in a skewed state on the magnetic tape MT (see Figures 13 to 15). If the pair of corresponding servo patterns 58 between servo bands SB were arranged without a predetermined offset in the longitudinal direction LD, a time difference would occur between the timing of reading one of the servo patterns 58 between the servo bands SB and the timing of reading the other servo pattern 58. Therefore, in the magnetic tape MT according to this embodiment, the corresponding servo patterns 58 between servo bands SB are offset by a predetermined offset in the longitudinal direction LD between adjacent servo bands SB in the width direction WD. This reduces the time difference between the timing of readings being performed on one of the servo patterns 58 between adjacent servo bands SB in the width direction WD and the timing of readings being performed on the other servo pattern 58, compared to the case where a pair of corresponding servo patterns 58 between adjacent servo bands SB are arranged without a predetermined shift in spacing (hereinafter, this effect will be referred to as the "ninth effect").

In this embodiment, the servo band SB is divided by a plurality of frames 56 (see Figures 9 and 11). Each frame 56 is defined based on a pair of servo patterns 58 (i.e., servo patterns 58A and 58B). In this embodiment, a pair of servo patterns 58 included in a pair of frames 56 that correspond to adjacent servo bands SB in the width direction WD is read by servo reading elements SR1 and SR2 included in the magnetic head 28. In this embodiment, the magnetic head 28 is used in a skewed state on the magnetic tape MT (see Figures 13 to 15). If, hypothetically, the pair of servo patterns 58 included in a pair of frames 56 that correspond to adjacent servo bands SB in the width direction WD are arranged without being shifted by a predetermined interval in the longitudinal direction LD, a time difference will occur between the timing at which a reading is performed on one of the servo patterns 58 and the timing at which a reading is performed on the other servo pattern 58. Therefore, in the magnetic tape MT according to this embodiment, a pair of servo patterns 58 contained in a pair of frames 56 that correspond to adjacent servo bands SB in the width direction WD are shifted by a predetermined interval in the longitudinal direction LD between adjacent servo bands SB in the width direction WD. This reduces the time difference between the timing of reading one servo pattern 58 and the timing of reading the other servo pattern 58, compared to the case where a pair of corresponding frames 56 between adjacent servo bands SB in the width direction WD are not shifted by a predetermined interval (hereinafter, this effect will be referred to as the "tenth effect").

In this embodiment, as shown in Figure 11, the predetermined interval is defined based on the angle α formed between frames 56 that are not corresponding to each other in the width direction WD and a virtual straight line C1, the servo band pitch, and the total length of the frame 56 in the longitudinal direction. That is, the predetermined interval is defined by equation (1) and calculated from equation (1). Therefore, compared to defining the predetermined interval without using angle α, servo band pitch, or the total length of the frame 56 in the longitudinal direction, the predetermined interval can be obtained more easily (hereinafter, this effect will be referred to as the "eleventh effect").

In this embodiment, the servo signal, which is the result of reading the servo pattern 58 by the servo reading element SR, is detected using the autocorrelation coefficient (see Figure 15). This allows for more accurate detection of the servo signal compared to detecting the servo signal using only a method that determines whether the signal level exceeds a threshold (hereinafter, this effect will be referred to as the "twelfth effect").

Next, we will explain the operation of the servowriter switch.

In the servo writer SW, when recording a servo pattern 58 onto the magnetic tape MT using the servo pattern recording head WH, the magnetic tape MT is sent to the transport path SW7 and driven at a constant speed. At this time, the magnetic tape MT is driven with the position of gap pattern G1 corresponding to the position of servo band SB3, the position of gap pattern G2 corresponding to the position of servo band SB2, and the position of gap pattern G3 corresponding to the position of servo band SB1. In this state, pulse signals for servo pattern 58A and pulse signals for servo pattern 58B are alternately supplied to the head cores WH2A, WH2B, and WH2C of the servo pattern recording head WH.

The gap pattern G consists of a pair of non-parallel linear regions. These non-parallel linear regions are: one with the same geometric characteristics as the magnetization line 60A1a located on the upstream end of the five magnetization lines 60A1a in the linear magnetization region 60A1 shown in Figure 9; and another with the same geometric characteristics as the magnetization line 60A2a located on the upstream end of the five magnetization lines 60A2a in the linear magnetization region 60A2 shown in Figure 9. Furthermore, gap patterns G1, G2, and G3 are offset by predetermined intervals along direction LD1.

Therefore, when pulse signals for servo pattern 58A are supplied to head cores WH2A, WH2B, and WH2C in phase, servo pattern 58A is recorded on servo bands SB3, SB2, and SB1 with a predetermined interval shift in the longitudinal direction LD. Similarly, when pulse signals for servo pattern 58B are supplied to head cores WH2A, WH2B, and WH2C in phase, servo pattern 58B is recorded on servo bands SB3, SB2, and SB1 with a predetermined interval shift in the longitudinal direction LD.

When the servo pattern 58A recorded on the servo band SB of the magnetic tape MT obtained in this way is read by the servo reading element SR included in the magnetic head 28, which is skewed on the magnetic tape MT, the first to twelfth effects are obtained.

As shown in Figure 20 as a comparative example, even when using the servo pattern recording head H, the servo pattern 58 can be recorded with a predetermined offset in the longitudinal direction LD relative to the servo bands SB3, SB2, and SB1. The servo pattern recording head H differs from the servo pattern recording head WH in that it has a base H1 instead of a base WH1. The base H1 is formed in a rectangular parallelepiped shape and is arranged to traverse the surface 31 of the magnetic tape MT running on the transport path SW7 along the width direction WD. The surface H1A of the base H1 is a rectangle with a long side H1Aa and a short side H1Ab, and the long side H1Aa traverses the surface 31 of the magnetic tape MT along the width direction WD.

The longer side H1Aa is longer than the width of the magnetic tape MT. The direction of the longer side H1Aa coincides with the width direction WD. The base H1 is positioned on the surface 31 side of the magnetic tape MT, with multiple gap patterns G facing the surface 31, and traversing the magnetic tape MT in the width direction WD.

In the servo pattern recording head H, similar to the servo pattern recording head WH, gap patterns G1, G2, and G3 are offset in the direction LD1 along the direction WD1 between adjacent gap patterns G by the predetermined interval described above (i.e., the predetermined interval calculated from formula (1)). The direction of the short side H1Ab coincides with the direction LD1, and the length of the short side H1Ab is sufficient to accommodate all of the gap patterns G1, G2, and G3. In other words, the length of the short side H1Ab is set to compensate for at least the amount by which gap patterns G1 to G3 are offset along the direction LD1 from gap pattern G1 to gap pattern G3.

In contrast, in the servo pattern recording head WH, the base body WH1 is positioned so that multiple gap patterns G and the surface 31 face each other on the surface 31 side of the magnetic tape MT, and is tilted along the surface 31 of the magnetic tape MT with respect to a virtual straight line C1 at an angle γ that absorbs the displacement of a predetermined interval. Therefore, in the servo pattern recording head WH, the amount by which gap patterns G1 to G3 are shifted along direction LD1 from gap pattern G1 to gap pattern G3 is taken into consideration as an extra amount, making it possible to make the length of the short side WH1Ab of the base body WH1 shorter than the short side H1Ab of the base body H1 shown in Figure 20. In other words, it is possible to make the area of surface WH1A smaller than the area of surface H1A shown in Figure 20. As a result, the area in which surface WH1A contacts the surface 31 of the magnetic tape MT (i.e., the area of the sliding surface WH1Ax shown in Figure 17) can be made smaller than the area in which surface H1A contacts the surface 31 of the magnetic tape MT shown in Figure 20. Therefore, the servo pattern recording head WH can suppress friction between the magnetic tape MT and surface WH1A compared to the servo pattern recording head H. Furthermore, suppressing friction contributes to stabilizing the movement of the magnetic tape MT.

Furthermore, in the servo writer SW, in-phase signals are used as pulse signals between multiple gap patterns G. Pulse signals for servo pattern 58A and pulse signals for servo pattern 58B are supplied alternately to head cores WH2A, WH2B, and WH2C. In the servo writer SW, gap patterns G1, G2, and G3 are shifted by a predetermined interval in the direction LD1. Therefore, by supplying pulse signals for servo pattern 58A in-phase to head cores WH2A, WH2B, and WH2C, the servo writer SW can record servo pattern 58A between adjacent servo bands SB1 to SB3 in the width direction WD, shifted by a predetermined interval in the longitudinal direction LD. Furthermore, the servo writer SW supplies pulse signals for the servo pattern 58B to head cores WH2A, WH2B, and WH2C in the same phase, thereby recording the servo pattern 58B for servo bands SB1 to SB3, shifted by a predetermined interval in the longitudinal direction LD between adjacent servo bands SB in the width direction WD.

Furthermore, in the servo writer SW, the control device SW5 operates as the position detection unit 30B shown in Figure 14, acquiring position detection results from the servo pattern reading results. The servo band SB is then inspected by determining the correctness of the servo pattern 58 using these position detection results. The control device SW5, operating as the position detection unit 30B, can detect the servo signal with greater accuracy compared to a method that only determines whether the signal level exceeds a threshold. Therefore, the servo writer SW can also perform accurate inspection of the servo band SB.

In the above embodiment, an example was described in which the servo band SB is divided by a plurality of frames 56 along the longitudinal direction LD, but the technology of this disclosure is not limited to this. For example, as shown in Figure 21, the servo band SB may be divided by frames 70 along the longitudinal direction LD. Each frame 70 is defined by a set of servo patterns 72. Multiple servo patterns 72 are recorded in the servo band SB along the longitudinal direction LD. The multiple servo patterns 72, like the multiple servo patterns 58, are arranged at regular intervals along the longitudinal direction LD.

In the example shown in Figure 21, servo patterns 72A and 72B are shown as an example of a pair of servo patterns 72. Each of servo patterns 72A and 72B is an M-shaped magnetized servo pattern. Servo patterns 72A and 72B are adjacent along the longitudinal direction LD, with servo pattern 72A located on the upstream side in the forward direction and servo pattern 72B located on the downstream side in the forward direction within the frame 70.

As an example, as shown in Figure 22, the servo pattern 72 consists of linear magnetization region pairs 74. The linear magnetization region pairs 74 are classified into linear magnetization region pairs 74A and linear magnetization region pairs 74B.

The servo pattern 72A consists of a pair of linear magnetization regions 74A. The pair of linear magnetization regions 74A are arranged adjacent to each other along the longitudinal direction LD.

In the example shown in Figure 22, linear magnetization regions 74A1 and 74A2 are shown as an example of a linear magnetization region pair 74A. The linear magnetization region pair 74A is configured similarly to the linear magnetization region pair 60A described in the above embodiment and has the same geometric characteristics as the linear magnetization region pair 60A. Specifically, linear magnetization region 74A1 is configured similarly to linear magnetization region 60A1 described in the above embodiment and has the same geometric characteristics as linear magnetization region 60A1, and linear magnetization region 74A2 is configured similarly to linear magnetization region 60A2 described in the above embodiment and has the same geometric characteristics as linear magnetization region 60A2.

The servo pattern 72B consists of a pair of linear magnetization regions 74B. The pair of linear magnetization regions 74B are arranged adjacent to each other along the longitudinal direction LD.

In the example shown in Figure 22, linear magnetization regions 74B1 and 74B2 are shown as an example of a linear magnetization region pair 74B. The linear magnetization region pair 74B is configured similarly to the linear magnetization region pair 60B described in the above embodiment and has the same geometric characteristics as the linear magnetization region pair 60B. Specifically, linear magnetization region 74B1 is configured similarly to linear magnetization region 60B1 described in the above embodiment and has the same geometric characteristics as linear magnetization region 60B1, and linear magnetization region 74B2 is configured similarly to linear magnetization region 60B2 described in the above embodiment and has the same geometric characteristics as linear magnetization region 60B2.

As an example, as shown in Figure 23, the servo pattern recording head WH used for recording the servo pattern 72 differs from the servo pattern recording head WH described in the above embodiment (i.e., the servo pattern recording head WH used for recording the servo pattern 58) in that it has a gap pattern G4 instead of a gap pattern G1, a gap pattern G5 instead of a gap pattern G2, and a gap pattern G6 instead of a gap pattern G3.

The gap pattern G4 consists of linear regions G4A, G4B, G4C, and G4D. Linear regions G4A and G4B are used to record one of the pair of linear magnetization regions 74A shown in Figure 22 (for example, the upstream linear magnetization region pair 74A in the forward direction), and linear regions G4C and G4D are used to record the other pair of linear magnetization regions 74A shown in Figure 22 (for example, the downstream linear magnetization region pair 74A in the forward direction). Furthermore, linear regions G4A and G4B are used to record one of the pair of linear magnetization regions 74B shown in Figure 22 (for example, the upstream linear magnetization region 74B in the forward direction), while linear regions G4C and G4D are used to record the other pair of linear magnetization regions 74B shown in Figure 22 (for example, the downstream linear magnetization region 74B in the forward direction).

The configurations of linear regions G4A and G4B are the same as those of linear regions G1A and G1B. That is, linear regions G4A and G4B have the same geometric properties as linear regions G1A and G1B. The configurations of linear regions G4C and G4D are the same as those of linear regions G4A and G4B. That is, linear regions G4C and G4D have the same geometric properties as linear regions G4A and G4B.

Gap pattern G5 consists of linear regions G5A, G5B, G5C, and G5D. The configuration of linear regions G5A, G5B, G5C, and G5D is the same as that of linear regions G4A, G4B, G4C, and G4D. That is, linear regions G5A, G5B, G5C, and G5D have the same geometric properties as linear regions G4A, G4B, G4C, and G4D.

Gap pattern G6 consists of linear regions G6A, G6B, G6C, and G6D. The configuration of linear regions G6A, G6B, G6C, and G6D is the same as that of linear regions G4A, G4B, G4C, and G4D. That is, linear regions G6A, G6B, G6C, and G6D have the same geometric properties as linear regions G4A, G4B, G4C, and G4D.

The gap patterns G4, G5, and G6 configured in this way are offset in the direction LD1 by the predetermined interval (i.e., the predetermined interval calculated from formula (1)) between adjacent gap patterns G along direction WD1.

The longer side WH1Aa of surface WH1A is longer than the width of the magnetic tape MT. The shorter side WH1Ab of surface WH1A is long enough to accommodate all of the gap patterns G4, G5, and G6. The base WH1 is positioned on the surface 31 side of the magnetic tape MT, facing the multiple gap patterns G and the surface 31, and traversing the magnetic tape MT diagonally, similar to the embodiment described above.

The pulse signals used between gap patterns G4, G5, and G6 (i.e., the pulse signals supplied from the first pulse signal generator SW4A to the head core WH2A, the pulse signals supplied from the second pulse signal generator SW4B to the head core WH2B, and the pulse signals supplied from the third pulse signal generator SW4C to the head core WH2C, as shown in Figure 23) are in phase.

In the servo pattern recording process, the magnetic tape MT travels along the transport path SW7 at a constant speed, with the position of gap pattern G4 corresponding to the position of servo band SB3, the position of gap pattern G5 corresponding to the position of servo band SB2, and the position of gap pattern G6 corresponding to the position of servo band SB1. In this state, pulse signals for servo pattern 72A and pulse signals for servo pattern 72B are alternately supplied to head cores WH2A, WH2B, and WH2C.

Here, when pulse signals for servo pattern 72A are supplied to head cores WH2A, WH2B, and WH2C in phase, servo pattern 72A is recorded on servo bands SB3, SB2, and SB1 with a predetermined interval shift in the longitudinal direction LD. Similarly, when pulse signals for servo pattern 72B are supplied to head cores WH2A, WH2B, and WH2C in phase, servo pattern 72B is recorded on servo bands SB3, SB2, and SB1 with a predetermined interval shift in the longitudinal direction LD.

The example shown in Figure 21 illustrates a configuration in which the servo band SB is divided into multiple frames 70 along the longitudinal direction LD, but the technology of this disclosure is not limited to this. For example, as shown in Figure 24, the servo band SB may be divided into frames 76 along the longitudinal direction LD. Each frame 76 is defined by a set of servo patterns 78. Multiple servo patterns 78 are recorded in the servo band SB along the longitudinal direction LD. The multiple servo patterns 78 are arranged at regular intervals along the longitudinal direction LD, similar to the multiple servo patterns 72 (see Figure 21).

In the example shown in Figure 24, servo patterns 78A and 78B are shown as an example of a pair of servo patterns 78. Each of servo patterns 78A and 78B is an N-shaped magnetized servo pattern. Servo patterns 78A and 78B are adjacent to each other along the longitudinal direction LD, with servo pattern 78A located on the upstream side in the forward direction and servo pattern 78B located on the downstream side in the forward direction within the frame 76.

As an example, as shown in Figure 25, the servo pattern 78 consists of a linear magnetization region group 80. The linear magnetization region group 80 is further classified into linear magnetization region group 80A and linear magnetization region group 80B.

The servo pattern 78A consists of a linear magnetization region group 80A. The linear magnetization region group 80A consists of linear magnetization regions 80A1, 80A2, and 80A3. The linear magnetization regions 80A1, 80A2, and 80A3 are arranged adjacent to each other along the longitudinal direction LD. The linear magnetization regions 80A1, 80A2, and 80A3 are arranged in the order of linear magnetization region 80A1, 80A2, and 80A3 from the upstream side in the forward direction.

The linear magnetization regions 80A1 and 80A2 are configured similarly to the linear magnetization region pair 74A shown in Figure 22, and have the same geometric characteristics as the linear magnetization region pair 74AA. That is, linear magnetization region 80A1 is configured similarly to linear magnetization region 74A1 shown in Figure 22, and has the same geometric characteristics as linear magnetization region 74A1; linear magnetization region 80A2 is configured similarly to linear magnetization region 74A2 shown in Figure 22, and has the same geometric characteristics as linear magnetization region 74A2. Furthermore, linear magnetization region 80A3 is configured similarly to linear magnetization region 80A1, and has the same geometric characteristics as linear magnetization region 80A1.

In the example shown in Figure 25, linear magnetization regions 80A1 and 80A2 are examples of a "pair of linear magnetization regions" relating to the technology of this disclosure. In this case, linear magnetization region 80A1 is an example of a "first linear magnetization region" relating to the technology of this disclosure, and linear magnetization region 80A2 is an example of a "second linear magnetization region" relating to the technology of this disclosure. Similarly, linear magnetization regions 80A2 and 80A3 are also examples of a "pair of linear magnetization regions" relating to the technology of this disclosure. In this case, linear magnetization region 80A3 is an example of a "first linear magnetization region" relating to the technology of this disclosure, and linear magnetization region 80A2 is an example of a "second linear magnetization region" relating to the technology of this disclosure.

The servo pattern 78B consists of a linear magnetization region group 80B. The linear magnetization region group 80B consists of linear magnetization regions 80B1, 80B2, and 80B3. The linear magnetization regions 80B1, 80B2, and 80B3 are arranged adjacent to each other along the longitudinal direction LD. The linear magnetization regions 80B1, 80B2, and 80B3 are arranged in the order of 80B1, 80B2, and 80B3 from the upstream side in the forward direction.

The linear magnetization regions 80B1 and 80B2 are configured similarly to the linear magnetization region pair 74B shown in Figure 22, and have the same geometric characteristics as the linear magnetization region pair 74BB. Specifically, linear magnetization region 80B1 is configured similarly to linear magnetization region 74B1 shown in Figure 22, and has the same geometric characteristics as linear magnetization region 74B1. Similarly, linear magnetization region 80B2 is configured similarly to linear magnetization region 74B2 shown in Figure 22, and has the same geometric characteristics as linear magnetization region 74B2. Furthermore, linear magnetization region 80B3 is configured similarly to linear magnetization region 80B1, and has the same geometric characteristics as linear magnetization region 80B1.

In the example shown in Figure 25, linear magnetization regions 80B1 and 80B2 are examples of a "pair of linear magnetization regions" relating to the technology of this disclosure. In this case, linear magnetization region 80B1 is an example of a "first linear magnetization region" relating to the technology of this disclosure, and linear magnetization region 80B2 is an example of a "second linear magnetization region" relating to the technology of this disclosure. Similarly, linear magnetization regions 80B2 and 80B3 are also examples of a "pair of linear magnetization regions" relating to the technology of this disclosure. In this case, linear magnetization region 80B3 is an example of a "first linear magnetization region" relating to the technology of this disclosure, and linear magnetization region 80B2 is an example of a "second linear magnetization region" relating to the technology of this disclosure.

As an example, as shown in Figure 26, the servo pattern recording head WH used for recording the servo pattern 78 differs from the servo pattern recording head WH shown in Figure 23 (i.e., the servo pattern recording head WH used for recording the servo pattern 72) in that it has a gap pattern G7 instead of gap pattern G4, a gap pattern G8 instead of gap pattern G5, and a gap pattern G9 instead of gap pattern G6.

The gap pattern G7 consists of linear regions G7A, G7B, and G7C. Linear region G7A is used for recording linear magnetization regions 80A1 and 80B1 (see Figure 25) within servoband SB3 (see Figure 24), linear region G7B is used for recording linear magnetization regions 80A2 and 80B2 (see Figure 25) within servoband SB3 (see Figure 24), and linear region G7C is used for recording linear magnetization regions 80A3 and 80B3 (see Figure 24) within servoband SB3 (see Figure 25).

The configurations of linear regions G7A, G7B, and G7C are the same as those of linear regions G4A, G4B, and G4C shown in Figure 23. That is, linear regions G7A, G7B, and G7C have the same geometric properties as linear regions G4A, G4B, and G4C.

The gap pattern G8 consists of linear regions G8A, G8B, and G8C. Linear region G8A is used for recording linear magnetization regions 80A1 and 80B1 (see Figure 25) within the servo band SB2 (see Figure 24). Linear region G8B is used for recording linear magnetization regions 80A2 and 80B2 (see Figure 25) within the servo band SB2 (see Figure 24). Linear region G8C is used for recording linear magnetization regions 80A3 and 80B3 (see Figure 25) within the servo band SB2 (see Figure 24).

The configurations of linear regions G8A, G8B, and G8C are the same as those of linear regions G5A, G5B, and G5C shown in Figure 23. That is, linear regions G8A, G8B, and G8C have the same geometric properties as linear regions G5A, G5B, and G5C.

The gap pattern G9 consists of linear regions G9A, G9B, and G9C. Linear region G9A is used for recording linear magnetization regions 80A1 and 80B1 (see Figure 25) within servoband SB1 (see Figure 24), linear region G9B is used for recording linear magnetization regions 80A2 and 80B2 (see Figure 25) within servoband SB1 (see Figure 24), and linear region G9C is used for recording linear magnetization regions 80A3 and 80B3 (see Figure 25) within servoband SB1 (see Figure 24).

The configurations of linear regions G9A, G9B, and G9C are the same as those of linear regions G6A, G6B, and G6C shown in Figure 23. That is, linear regions G9A, G9B, and G9C have the same geometric properties as linear regions G6A, G6B, and G6C.

The gap patterns G7, G8, and G9 configured in this way are offset in the direction LD1 by the predetermined interval (i.e., the predetermined interval calculated from formula (1)) between adjacent gap patterns G along direction WD1.

The longer side WH1Aa of surface WH1A is longer than the width of the magnetic tape MT. The shorter side WH1Ab of surface WH1A is long enough to accommodate all of the gap patterns G7, G8, and G9. The base WH1 is positioned on the surface 31 side of the magnetic tape MT, facing the multiple gap patterns G and the surface 31, and traversing the magnetic tape MT diagonally, similar to the embodiment described above.

The pulse signals used between gap patterns G7, G8, and G9 (i.e., the pulse signals supplied from the first pulse signal generator SW4A to the head core WH2A, the pulse signals supplied from the second pulse signal generator SW4B to the head core WH2B, and the pulse signals supplied from the third pulse signal generator SW4C to the head core WH2C, as shown in Figure 23) are in phase.

In the servo pattern recording process, the magnetic tape MT travels along the transport path SW7 at a constant speed, with the position of gap pattern G7 corresponding to the position of servo band SB3, the position of gap pattern G8 corresponding to the position of servo band SB2, and the position of gap pattern G9 corresponding to the position of servo band SB1. In this state, pulse signals for servo pattern 80A and pulse signals for servo pattern 80B are alternately supplied to head cores WH2A, WH2B, and WH2C.

Here, when pulse signals for servo pattern 80A are supplied to head cores WH2A, WH2B, and WH2C in phase, servo pattern 80A is recorded on servo bands SB3, SB2, and SB1 with a predetermined interval shift in the longitudinal direction LD. Similarly, when pulse signals for servo pattern 80B are supplied to head cores WH2A, WH2B, and WH2C in phase, servo pattern 80B is recorded on servo bands SB3, SB2, and SB1 with a predetermined interval shift in the longitudinal direction LD.

In the above embodiment, an example was described in which the default interval is defined based on the angle α, the servo band pitch, and the frame length. However, the technology of this disclosure is not limited thereto, and the default interval may be defined without using the frame length. For example, as shown in Figure 27, the default interval is defined based on the angle α formed between the corresponding frames 56 (line segment L3 in the example shown in Figure 27) and the virtual line C1 in the width direction WD, 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 default interval is calculated from the following formula (2).

(Default interval) = (Servo band pitch) × tanα .... (2)

Thus, formula (2) does not include the frame length. This means that the default interval can be calculated without considering the frame length. Therefore, this configuration allows for simpler calculation of the default interval compared to calculating it from formula (1).

In the above embodiment, a magnetic tape system 10 in which a magnetic tape cartridge 12 can be inserted into and removed from a magnetic tape drive 14 was illustrated, but the technology of this disclosure is not limited thereto. For example, the technology of this disclosure also applies 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).

In the above embodiment, a single magnetic head 28 was illustrated, but the technology of this disclosure is not limited thereto. For example, multiple magnetic heads 28 may be arranged on the magnetic tape MT. For example, a reading magnetic head 28 and at least one writing magnetic head 28 may be arranged on the magnetic tape MT. The reading magnetic head 28 may be used to verify the data recorded in the data band DB by the writing magnetic head 28. Alternatively, a single magnetic head equipped with a reading magnetic element unit 42 and at least one writing magnetic element unit 42 may be arranged on the magnetic tape MT.

The descriptions and illustrations presented above are detailed explanations of the technical aspects of this disclosure and represent only one example of the technology. For example, the above descriptions of the structure, function, operation, and effects are examples of the structure, function, operation, and effects of the technical aspects of this disclosure. Therefore, it goes without saying that you may delete unnecessary parts, add new elements, or replace elements in the descriptions and illustrations presented above, as long as you do not deviate from the essence of the technology presented. Furthermore, to avoid confusion and facilitate understanding of the technical aspects of this disclosure, explanations of common technical knowledge and other information that do not require special explanation to enable the implementation of the technology have been omitted from the descriptions and illustrations presented above.

In this specification, "A and/or B" is synonymous with "at least one of A and B." That is, "A and/or B" means that it could be A alone, B alone, or a combination of A and B. Furthermore, in this specification, the same concept applies when expressing three or more things linked by "and/or."

All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted as being incorporated by reference.

The following additional information is disclosed regarding the embodiments described above.

(Note 1)
Substrate and,
A servo pattern recording head comprising a plurality of gap patterns formed on the surface of the above-mentioned substrate,
The above multiple gap patterns are,
The above surface is formed in a direction corresponding to the width direction of the magnetic tape,
Multiple servo patterns are recorded in the width direction by applying a magnetic field to the magnetic tape according to the supplied pulse signal.
The above gap pattern is at least one pair of linear regions,
The first linear region, which is one of the pair of linear regions described above, and the second linear region, which is the other of the pair of linear regions described above, are tilted in directions opposite to the first virtual line along the direction corresponding to the width direction on the surface.
The first linear region described above has a steeper angle of inclination with respect to the first virtual line than the second linear region described above.
The positions of both ends of the first linear region and the positions of both ends of the second linear region are aligned in a direction corresponding to the width direction of the magnetic tape.
The above multiple gap patterns are offset by a predetermined interval in the direction corresponding to the longitudinal direction of the magnetic tape, between adjacent gap patterns along the direction corresponding to the width direction.
The above-mentioned substrate is a servo pattern recording head tilted along the magnetic tape with respect to the first virtual straight line at an angle that absorbs the deviation of the predetermined interval.

10 Magnetic tape system 12 Magnetic tape cartridge 14 Magnetic tape drive 16 Case 16A Right wall 16B Opening 18 Upper case 20 Lower case 22, SW1 Delivery reel 22A Reel hub 22B1 Upper flange 22B2 Lower flange 24 Cartridge memory 24B, 33 Back surface 26 Transport device 28 Magnetic head 29A Magnetic layer 29B Base film 29C Back coat layer 30, SW5 Control device 30A Control unit 30B Position detection unit 30B1 First position detection unit 30B2 Second position detection unit 31, H1A, WH1A Front surface 32 Storage 34 UI system device 35 Communication interface 36 Delivery motor 37 External device 38, SW2 Take-up reel 40 Take-up motor 42 Magnetic element unit 44 Holder 46 Non-contact read/write device 48 Moving mechanism 48A Moving actuator 49 Tilting mechanism 49A Tilting actuators 50, 56, 70, 76 Frames 52, 52A, 52B, 58, 58A, 58B, 72, 72A, 72B, 78, 78A, 78B Servo patterns 54, 54A, 54B, 60, 60A, 60B, 74, 74A, 74B Linear magnetization region pairs 54A1, 54A2, 54B1, 54B2, 60A1, 60A2, 60B1, 60B2, 74A1, 74A2, 74B1, 74B2, 80A1, 80A2, 80A3 Linear magnetization regions 54A1a, 54A2a, 54B1a, 54B2a, 60A1a, 60A2a, 60B1a, 60B2a Magnetization line 62 Virtual linear region pair 62A, 62B Virtual linear region 62A1, 62B1 Line 66 Ideal waveform signal 68 Virtual linear region pair 68A, 68B Virtual linear region 80, 80A, 80B Linear magnetization region group A, B, C Arrows a, b, α, β, γ Angle C1, C2, C3, C4 Virtual line C5 Extension lines DB, DB1, DB2 Data band DRW Data read/write elements G, G1, G2, G3, G4, G5, G6, G7, G8, G9 Gap patterns G1A, G1B, G2A, G2B, G3A, G3B, G4A, G4B, G4C, G4D, G5A, G5B, G5C, G5D, G6A, G6B, G6C, G6D, G7A, G7B, G7C, G8A, G8B, G8C, G9A, G9B, G9C Linear region GR Guide rollers H, WH Servo pattern recording heads H1, WH1 Base H1Aa, WH1Aa Long side H1Ab, WH1Ab Short side L0, L1, L2 Line segment LD Long direction LD1, WD1 Direction MF Magnetic field MT, MT0 Magnetic tape O1, O2 Center RA Rotation axis SA1, SA2 Symmetry axis SB, SB1, SB2, SB3 Servo bands SR, SR1, SR2 Servo reading element SW Servo writer SW3 Drive unit SW4 Pulse signal generator SW4A First pulse signal generator SW4B Second pulse signal generator SW4C Third pulse signal generator SW6 Guide SW7 Conveyor path VH Verify head WD Width direction WH1 Base WH1Aa Long side WH1Ab Short side WH1Ax Sliding surfaces WH2, WH2A, WH2B, WH2C Head core

Claims (18)

A pulse signal generator,
A servo pattern recording device comprising a servo pattern recording head,
The pulse signal generator generates a pulse signal,
The servo pattern recording head has a base and a plurality of gap patterns formed on the surface of the base, and records a plurality of servo patterns in the width direction of the magnetic tape by applying a magnetic field to the magnetic tape from the plurality of gap patterns in accordance with the pulse signal.
The plurality of gap patterns are formed on the surface along the direction corresponding to the width direction,
The gap pattern is at least one pair of linear regions,
The first linear region, which is one of the pair of linear regions, and the second linear region, which is the other of the pair of linear regions, are tilted in directions opposite to the first virtual line along the direction corresponding to the width direction on the surface.
The first linear region has a steeper angle of inclination with respect to the first virtual line than the second linear region.
The positions of both ends of the first linear region and the positions of both ends of the second linear region are aligned in a direction corresponding to the width direction of the magnetic tape.
The plurality of gap patterns are offset by a predetermined interval in the direction corresponding to the longitudinal direction of the magnetic tape, between adjacent gap patterns along the direction corresponding to the width direction.
A servo pattern recording device in which the base is tilted along the magnetic tape with respect to the first virtual line at an angle that absorbs the deviation of the predetermined interval. The servo pattern recording apparatus according to claim 1, wherein the substrate is formed in the shape of a rectangular parallelepiped and diagonally crosses the magnetic tape. The surface is formed in a rectangular shape having a long side and a short side,
The servo pattern recording device according to claim 2, wherein the length of the shorter side is the length that accommodates the plurality of servo patterns. The servo pattern recording device according to claim 1, wherein the total length of the first linear region is shorter than the total length of the second linear region. The servo pattern recording device according to claim 1, wherein the geometric characteristics of the pair of linear regions on the surface correspond to the geometric characteristics obtained when the entire pair of virtual linear regions is tilted with respect to the first virtual line by tilting the axis of symmetry of the pair of virtual linear regions, which are tilted symmetrically with respect to the first virtual line, with respect to the first virtual line, and the positions of both ends of one of the pair of virtual linear regions and the positions of both ends of the other virtual linear region are aligned in a direction corresponding to the width direction. The magnetic tape has a plurality of servo bands formed along the width direction,
The servo band is divided into frames defined based on at least one set of the servo patterns,
The servo pattern recording device according to claim 1, wherein the predetermined interval is defined based on the angle formed between the frames corresponding to adjacent servo bands in the width direction and the first virtual line, and the pitch between adjacent servo bands in the width direction. The magnetic tape has a plurality of servo bands formed along the width direction,
The servo band is divided into frames defined based on at least one set of the servo patterns,
The servo pattern recording device according to claim 1, wherein the predetermined interval is defined based on the angle between the frames that are not in a corresponding relationship between adjacent servo bands in the width direction and the first virtual straight line, the pitch between adjacent servo bands in the width direction, and the total length of the frame in the longitudinal direction. The servo pattern recording device according to claim 1, wherein the pulse signals used between the plurality of gap patterns are in-phase signals. A magnetic tape on which multiple servo patterns are recorded by a servo pattern recording device according to any one of claims 1 to 8. The magnetic tape according to claim 9,
A case containing the aforementioned magnetic tape,
A magnetic tape cartridge equipped with [a specific feature/feature]. A travel mechanism for traveling the magnetic tape described in claim 9 along a predetermined path,
A magnetic tape drive comprising: a magnetic head having a plurality of servo reading elements that read the servo pattern on the predetermined path while the magnetic tape is being driven by the aforementioned travel mechanism,
The plurality of servo reading elements are arranged along the longitudinal direction of the magnetic head,
The magnetic tape drive is configured such that the magnetic head is positioned such that a second virtual straight line along the longitudinal direction of the magnetic head is inclined with respect to the direction of travel of the magnetic tape. The magnetic tape according to claim 9,
A magnetic tape system comprising: a magnetic tape drive equipped with a magnetic head having a plurality of servo reading elements for reading the servo pattern on the predetermined path while the magnetic tape is running along the predetermined path,
The plurality of servo reading elements are arranged along the longitudinal direction of the magnetic head,
A magnetic tape system in which the magnetic head is positioned such that a third virtual straight line along the longitudinal direction of the magnetic head is inclined with respect to the direction of travel of the magnetic tape. A detection device equipped with a processor,
The processor calculates the autocorrelation coefficient for the servo signal, which is the result of reading the servo pattern from the magnetic tape described in claim 9 by the servo reading element.
A detection device that detects the servo signal based on the calculated autocorrelation coefficient. To generate a pulse signal,
The process includes recording a plurality of servo patterns in the width direction of a magnetic tape by applying a magnetic field to the magnetic tape from the plurality of gap patterns in accordance with the pulse signal, using a servo pattern recording head having a substrate and a plurality of gap patterns formed on the surface of the substrate,
The plurality of gap patterns are formed on the surface along the direction corresponding to the width direction,
The gap pattern is at least one pair of linear regions,
The first linear region, which is one of the pair of linear regions, and the second linear region, which is the other of the pair of linear regions, are tilted in directions opposite to the first virtual line along the direction corresponding to the width direction on the surface.
The first linear region has a steeper angle of inclination with respect to the first virtual line than the second linear region.
The positions of both ends of the first linear region and the positions of both ends of the second linear region are aligned in a direction corresponding to the width direction of the magnetic tape.
The plurality of gap patterns are offset by a predetermined interval in the direction corresponding to the longitudinal direction of the magnetic tape, between adjacent gap patterns along the direction corresponding to the width direction.
A servo pattern recording method wherein the substrate is tilted along the magnetic tape with respect to the first virtual line at an angle that absorbs the deviation of the predetermined interval. A first step of recording a plurality of servo patterns on a magnetic tape according to the servo pattern recording method described in claim 14,
A method for manufacturing a magnetic tape, comprising a second step of winding up the magnetic tape. An inspection device used in conjunction with the servo pattern recording device described in claim 1,
The detection device according to claim 13 ,
An inspection processor that inspects the servo band on the magnetic tape where the servo pattern is recorded, based on the servo signal detected by the detection device,
An inspection device equipped with the following features. A detection method used in conjunction with the servo pattern recording method described in claim 14,
To calculate the autocorrelation coefficient of the servo signal, which is the result of reading the servo pattern from the magnetic tape described in claim 9 by a servo reading element, and
A detection method comprising detecting the servo signal based on the calculated autocorrelation coefficient. Based on the servo signal detected by the detection method described in claim 17, the servo band on which the servo pattern is recorded in the magnetic tape is inspected, and
An inspection method that includes determining whether the servo pattern is correct or incorrect.