WO2022196225A1 - サーボパターン記録方法、サーボパターン記録装置、磁気テープの製造方法、磁気テープ及びテープカートリッジ - Google Patents
サーボパターン記録方法、サーボパターン記録装置、磁気テープの製造方法、磁気テープ及びテープカートリッジ Download PDFInfo
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Images
Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B5/584—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on tapes
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B21/00—Head arrangements not specific to the method of recording or reproducing
- G11B21/02—Driving or moving of heads
- G11B21/10—Track finding or aligning by moving the head ; Provisions for maintaining alignment of the head relative to the track during transducing operation, i.e. track following
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
- G11B23/02—Containers; Storing means both adapted to cooperate with the recording or reproducing means
- G11B23/04—Magazines; Cassettes for webs or filaments
- G11B23/08—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends
- G11B23/107—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends using one reel or core, one end of the record carrier coming out of the magazine or cassette
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B25/00—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus
- G11B25/06—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus using web-form record carriers, e.g. tape
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/02—Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
- G11B5/09—Digital recording
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/74—Record carriers characterised by the form, e.g. sheet shaped to wrap around a drum
- G11B5/78—Tape carriers
Definitions
- the present technology relates to a servo pattern recording method, a servo pattern recording device, a magnetic tape manufacturing method, a magnetic tape, and a tape cartridge.
- magnetic recording media have been widely used for purposes such as backing up electronic data.
- a magnetic tape cartridge is attracting more and more attention as a storage medium for big data and the like because of its large capacity and long-term storage capability.
- a magnetic tape conforming to the LTO (Linear Tape Open) standard is provided with multiple data bands parallel to the longitudinal direction of the tape, and data is recorded on multiple recording tracks within these multiple data bands. Further, the magnetic tape is provided with a plurality of servo bands parallel to the longitudinal direction of the tape, and each data band is arranged on the magnetic layer so as to be sandwiched between the plurality of servo bands. Each servo band carries out positioning (tracking) control of the recording/reproducing head with respect to each recording track, and furthermore, there is a servo pattern of a predetermined shape in which tape information and servo band identification information for specifying the data band are embedded. It is recorded (see Patent Documents 1 and 2, for example).
- Magnetic tapes are typically manufactured through processes such as coating a base film with a magnetic material, calendering, cutting, and recording servo patterns. Since these treatments are performed while the base film is being wound with a constant tension, the completed magnetic tape has internal strain and tends to widen with the passage of time. Therefore, when data is recorded or reproduced by a tape drive device, even if the magnetic tape is run with the same tension as when recording the servo pattern, the width of the magnetic tape is the same as the width of the magnetic tape when recording the servo pattern. It may increase more than the dimension. In this case, since the intervals between adjacent servo bands change, the intervals between the servo patterns recorded in these servo bands also fluctuate. As a result, desired tracking control becomes difficult. Such a problem can occur significantly due to the thinning of magnetic tapes accompanying the recent increase in recording capacity.
- an object of the present technology is to provide a servo pattern recording method, a servo pattern recording apparatus, a magnetic tape manufacturing method, a magnetic tape, and a tape cartridge that can ensure desired tracking control. It is in.
- a servo pattern recording method is a method of recording a servo pattern in a plurality of servo bands arranged at intervals in the width direction of a magnetic layer of a magnetic tape, running the magnetic tape at a predetermined tension; The plurality of A servo pattern is recorded in the servo band.
- a servo pattern recording device is a device for recording servo patterns in a plurality of servo bands arranged at intervals in a width direction of a magnetic layer of a magnetic tape, A servo write head having a plurality of correspondingly positioned recording portions is provided.
- the plurality of recording sections comprise a second pitch narrower than a first pitch, which is an arrangement interval between two servo read heads in a tape drive device that records data on the magnetic layer or reproduces data recorded on the magnetic layer. , each having a magnetic gap for recording a servo pattern in the plurality of servo bands.
- a method for manufacturing a magnetic tape according to one embodiment of the present technology is a method for manufacturing a magnetic tape including a magnetic layer having a plurality of servo bands arranged at intervals in the width direction, running the magnetic tape at a predetermined tension; The plurality of A servo pattern is recorded in the servo band.
- a magnetic tape which is one form of the present technology, includes a magnetic layer having a plurality of servo bands spaced apart in a width direction.
- the magnetic layer has two servo read heads in a tape drive device in which a servo band pitch, which is the distance between two adjacent servo bands, records information on the magnetic layer or reproduces information recorded on the magnetic layer. At least a part of the area has an area narrower than the arrangement interval of the .
- a tape cartridge includes a cartridge case, a tape reel rotatably housed inside the cartridge case, and a magnetic tape wound around the tape reel.
- the magnetic tape has a magnetic layer on which a plurality of servo patterns are recorded at intervals in the tape width direction.
- the magnetic layer has two servo read heads in a tape drive device in which a servo band pitch, which is the distance between two adjacent servo bands, records information on the magnetic layer or reproduces information recorded on the magnetic layer. and a second region in which the servo band pitch is wider than the arrangement interval of the two servo read heads.
- FIG. 1 is an exploded perspective view of a tape cartridge according to an embodiment of the present technology
- FIG. 1 is a schematic side view of a magnetic tape according to an embodiment of the present technology
- FIG. 2 is a schematic diagram of the magnetic tape as viewed from above (magnetic layer side)
- FIG. 4 is an enlarged view showing recording tracks in the data band of the magnetic tape
- FIG. 4 is an enlarged view showing a servo pattern written on the servo band of the magnetic tape
- FIG. 1 illustrates a tape drive device
- FIG. 3 is a schematic diagram of a drive head in the tape drive device
- FIG. 4 is a diagram showing a state when the tape drive device is recording/reproducing data signals; 1 is a front view showing a servo pattern recording device according to an embodiment of the present technology; FIG. It is a partially enlarged view showing a part of the servo pattern recording device.
- (A) is a diagram showing the data structure of an LPOS word embedded in a servo pattern, and (B) is a diagram explaining a manufacturer word.
- (A) is a schematic plan view showing an arrangement example of a servo pattern 6, and (B) is a diagram showing its reproduced waveform.
- FIG. 4 is a schematic diagram showing a configuration example of a first servo pattern and a second servo pattern; 4A and 4B are diagrams respectively showing reproduced waveforms of the first servo pattern and the second servo pattern;
- FIG. 3 is a perspective view schematically showing the configuration of a servo write head in the servo pattern recording device;
- FIG. It is a block diagram which shows the structure of the drive part in the said servo pattern recording device.
- FIG. 4 is a diagram schematically showing recording signal waveforms of a first servo subframe in a first pulse signal and a second pulse signal; FIG.
- FIG. 4 is a diagram showing an arrangement interval of magnetic gaps provided in the servo write head; It is a figure which shows the result of one experiment of the servo band pitch of the magnetic tape measured using the tape drive device.
- FIG. 10 is a diagram showing another experimental result of the servo band pitch of the magnetic tape measured using the tape drive device;
- FIG. 10 is a diagram showing still another experimental result of the servo band pitch of the magnetic tape measured using the tape drive device; It is a figure explaining the measuring method of the servo band pitch using the said tape drive apparatus.
- FIG. 4 is an explanatory diagram of a method of measuring a servo trace line;
- FIG. 2 is an explanatory diagram of the particle shape of hexagonal ferrite, which is a magnetic powder;
- FIG. 1 is an exploded perspective view showing a tape cartridge 10 according to one embodiment of the present technology.
- the tape cartridge 10 a tape cartridge complying with the LTO standard will be described as an example.
- the tape cartridge 10 includes a cartridge case 11, a tape reel 13, and a magnetic tape 1.
- the cartridge case 11 is constructed by connecting an upper shell 11a and a lower shell 11b with a plurality of screw members.
- a single tape reel 13 around which the magnetic tape 1 is wound is rotatably accommodated inside the cartridge case 11 .
- a chucking gear (not shown) that engages with the spindle 31 (see FIG. 6) of the tape drive device 30 is annularly formed in the center of the bottom of the tape reel 13 .
- This chucking gear is exposed to the outside through an opening 14 formed in the center of the lower shell 11b.
- An annular metal plate 15 that is magnetically attracted to the spindle 31 is fixed to the inner peripheral side of the chucking gear.
- a reel spring 16 Between the inner surface of the upper shell 11a and the tape reel 13, a reel spring 16, a reel lock member 17 and a spider 18 are arranged. These constitute a reel lock mechanism that prevents rotation of the tape reel 13 when the cartridge 10 is not in use.
- One side wall of the cartridge case 11 is provided with a tape pull-out port 19 for pulling out one end of the magnetic tape 1 to the outside.
- a slide door 20 for opening and closing the tape outlet 19 is arranged inside the side wall.
- the slide door 20 is configured to slide in the direction of opening the tape outlet 19 against the urging force of the torsion spring 21 by engagement with a tape loading mechanism (not shown) of the tape drive device 30 .
- a leader pin 22 is fixed to one end of the magnetic tape 1 .
- the leader pin 22 is detachably attached to a pin holding portion 23 provided inside the tape outlet 19 .
- the pin holding portion 23 elastically holds the upper end portion and the lower end portion of the leader pin 22 on the inner surface of the upper wall (the inner surface of the upper shell 11a) and the inner surface of the bottom wall (the inner surface of the lower shell 11b) of the cartridge case 11, respectively.
- a retainer 24 is provided.
- a cartridge memory 9 is arranged.
- FIG. 2 is a schematic diagram of the magnetic tape 1 viewed from the side
- FIG. 3 is a schematic diagram of the magnetic tape 1 viewed from above (magnetic layer 43 side).
- the magnetic tape 1 is long in the longitudinal direction (X-axis direction), short in the width direction (Y-axis direction), and thin in the thickness direction (Z-axis direction). ing.
- the magnetic tape 1 includes a tape-shaped substrate 41 elongated in the longitudinal direction (X-axis direction), an underlayer (non-magnetic layer) 42 provided on one main surface of the substrate 41, and a It includes a magnetic layer 43 provided and a back layer 44 provided on the other main surface of the substrate 41 .
- the back layer 44 may be provided as required, and the back layer 44 may be omitted.
- the magnetic tape 1 may be a perpendicular recording magnetic recording medium or a longitudinal recording magnetic recording medium.
- the magnetic layer 43 may be a coated film of a magnetic material, or may be a deposited film or a sputtered film of a magnetic material. Details of each layer constituting the magnetic tape 1 will be described later.
- the magnetic layer 43 includes a plurality of data bands d (data bands d0 to d3) elongated in the longitudinal direction (X-axis direction) in which data is written, and a plurality of longitudinally elongated bands d0 to d3 in which the servo pattern 6 is written. of servo bands s (servo bands s0 to s4).
- the servo bands s are arranged at positions sandwiching the data bands d in the width direction (Y-axis direction).
- the ratio of the area of the servo band s to the area of the entire surface of the magnetic layer 43 is typically 4.0% or less.
- the width of the servo band s is 1/2 inch tape width, for example, 96 ⁇ m or less.
- the ratio of the area of the servo band s to the area of the entire surface of the magnetic layer 43 can be obtained, for example, by developing the magnetic tape 1 using a developer such as a ferricolloid developer, and then observing the developed magnetic tape 1 with an optical microscope. It can be measured by observation.
- the number of data bands d is four and the number of servo bands s is five.
- the number of data bands d and the number of servo bands s can be changed as appropriate.
- the data band d includes a plurality of recording tracks 5 that are long in the longitudinal direction and aligned in the width direction.
- the number of recording tracks 5 included in one data band d is, for example, approximately 1,000 to 2,000. Data is recorded within the recording track 5 along this recording track 5 .
- One bit length in the longitudinal direction of the data recorded in the data band d is, for example, 48 nm or less.
- the servo band s includes a servo pattern 6 having a predetermined shape recorded by a servo pattern recording device (see FIG. 9), which will be described later.
- the number of recording tracks 5 increases with each generation, and the recording capacity is dramatically improved.
- the number of recording tracks 5 in the original LTO-1 was 384, but the number of recording tracks 5 in LTO-2 to LTO8 was 512, 704, 896 and 1280 respectively. , 2176, 3584 and 6656.
- the data recording capacity was 100 GB (gigabytes) for LTO-1, but 200 GB, 400 GB, 800 GB, 1.5 TB (terabytes), and 2.5 TB for LTO-2 to LTO-8 respectively. , 6.0 TB and 12 TB.
- the number of recording tracks 5 and the recording capacity are not particularly limited, and can be changed as appropriate. However, for example, when applied to a magnetic tape 1 that has a large number of recording tracks 5 and a large recording capacity (e.g., 6656 or more, 12 TB or more: LTO8 or later) and is susceptible to fluctuations in the width of the magnetic tape 1.
- a large recording capacity e.g., 6656 or more, 12 TB or more: LTO8 or later
- FIG. 4 is an enlarged view showing the recording track 5 in the data band d.
- the recording tracks 5 are long in the longitudinal direction, aligned in the width direction, and have a predetermined recording track width (track pitch) Wd for each track in the width direction.
- the recording track width Wd is typically 2.0 ⁇ m or less. Note that such a recording track width Wd can be obtained, for example, by developing the magnetic layer 43 of the magnetic tape 1 using a developer such as a ferricoloid developer, and then observing the developed magnetic layer 43 of the magnetic tape 1 with an optical microscope.
- Width Wd can be measured.
- FIG. 5 is an enlarged view showing the servo pattern 6 written in the servo band s.
- the servo pattern 6 includes a plurality of stripes inclined at a predetermined azimuth angle ⁇ with respect to the width direction (Y-axis direction), details of which will be described later.
- the plurality of stripes are classified into a first stripe group 61 inclined clockwise with respect to the width direction (Y-axis direction) and a second stripe group 62 inclined counterclockwise with respect to the width direction. be.
- First stripe group 61 and second stripe group 62 typically include four or five stripes.
- the shape of the servo pattern 6 can be determined, for example, by developing the magnetic layer 43 of the magnetic tape 1 using a developer such as a ferricolloid developer, and then observing the developed magnetic layer 43 of the magnetic tape 1 with an optical microscope. It can be measured by observation.
- a developer such as a ferricolloid developer
- a servo trace line T which is a line traced on the servo pattern 6 by a servo read head 132 (see FIG. 7), which will be described later, is indicated by a dashed line.
- the servo trace lines T are set along the longitudinal direction (X-axis direction) and are set at predetermined intervals Ps in the width direction.
- the number of servo trace lines T per one servo band s is, for example, about 30 to 60.
- the interval Ps between two adjacent servo trace lines T is the same as the recording track width Wd, for example, 2.0 ⁇ m or less.
- the interval Ps between two adjacent servo trace lines T is a value that determines the recording track width Wd. That is, when the interval Ps between the servo trace lines T is narrowed, the recording track width Wd is reduced and the number of recording tracks 5 included in one data band d is increased. As a result, the data recording capacity increases.
- FIG. 6 is a diagram showing the tape drive device 30. As shown in FIG.
- the tape drive device 30 is a data recording/reproducing device capable of recording data on the magnetic tape 1 or reproducing data recorded on the magnetic tape 1 .
- the tape drive device 30 is configured so that the cartridge 10 can be loaded.
- the tape drive device 30 is configured to be able to load one cartridge 10, but may be configured to be capable of loading a plurality of cartridges 10 at the same time.
- the tape drive device 30 includes a spindle 31, a take-up reel 32, a spindle drive device 33, a reel drive device 34, a plurality of guide rollers 35, a drive head 36, a reader/writer 37, and a control device 38. Prepare.
- the tape drive device 30 may further include a thermometer 39, a hygrometer 40, and the like.
- the spindle 31 has a head portion that engages the chucking gear of the tape reel 13 through the opening 14 formed in the lower shell 11b of the cartridge 10.
- the spindle 31 raises the tape reel 13 by a predetermined distance against the urging force of the reel spring 16 to release the reel lock function of the reel lock member 17 .
- the tape reel 13 is rotatably supported inside the cartridge case 11 by the spindle 31 .
- the spindle driving device 33 rotates the spindle 31 according to a command from the control device 38.
- the take-up reel 32 is configured to be capable of fixing the leading end (leader pin 22) of the magnetic tape 1 pulled out from the cartridge 10 via a tape loading mechanism (not shown).
- a plurality of guide rollers 35 guide the running of the magnetic tape 1 so that the tape path formed between the cartridge 10 and the take-up reel 32 has a predetermined relative positional relationship with respect to the drive head 36 .
- the reel driving device 34 rotates the take-up reel 32 according to a command from the control device 38 .
- the running direction of the magnetic tape 1 is the forward direction indicated by arrow A1 in FIG. rewinding direction toward the reel 13 side).
- the rotation of the spindle 31 by the spindle drive device 33 and the rotation of the take-up reel 32 by the reel drive device 34 are controlled to control the longitudinal direction (X-axis direction) of the magnetic tape 1 during data recording/reproducing.
- the tension at is adjustable.
- the tension of the magnetic tape 1 is adjusted by controlling the movement of the guide roller 35 instead of (or in addition to) controlling the rotation of the spindle 31 and the take-up reel 32, and a tension control unit including a dancer roller. etc. may be performed.
- the reader/writer 37 is configured to be able to record management information in the cartridge memory 9 according to commands from the control device 38 . Also, the reader/writer 37 is configured to be able to read the management information from the cartridge memory 9 according to a command from the control device 38 . As a communication method between the reader/writer 37 and the cartridge memory 9, for example, the ISO14443 method is adopted.
- the control device 38 includes, for example, a control section, a storage section, a communication section, and the like.
- the control unit is composed of, for example, a CPU (Central Processing Unit) or the like, and comprehensively controls each unit of the tape drive device 30 according to a program stored in the storage unit.
- CPU Central Processing Unit
- the storage unit includes a non-volatile memory in which various data and various programs are recorded, and a volatile memory used as a work area for the control unit.
- the various programs described above may be read from a portable recording medium such as an optical disk or a semiconductor memory, or may be downloaded from a server device on a network.
- the storage unit temporarily or non-temporarily stores the information of the cartridge memory 9 read from the reader/writer 27, the output of the thermometer 39 and the hygrometer 40, and the like.
- the communication unit is configured to be able to communicate with other devices such as a PC (Personal Computer) and a server device.
- the drive head 36 is configured to be able to record data on the magnetic tape 1 according to commands from the control device 38 . Further, the drive head 36 is configured to be able to reproduce data written on the magnetic tape 1 according to commands from the control device 38 .
- the drive head 36 is composed of a head unit having, for example, two servo read heads, a plurality of data write/read heads, and the like.
- FIG. 7 is a schematic view of the drive head 36 viewed from below (tape running surface).
- the drive head 36 includes a first drive head portion 36a and a second drive head portion 36b.
- the first drive head portion 36a and the second drive head portion 36b are configured symmetrically in the X'-axis direction (running direction of the magnetic tape 1 (the X-axis direction in FIG. 3)).
- the first drive head portion 36a and the second drive head portion 36b are configured to be movable in the width direction of the magnetic tape 1 (the Y-axis direction in FIG. 3).
- the first drive head portion 36a is a drive head used when the magnetic tape 1 is running in the forward direction (the A1 direction in FIG. 6).
- the second drive head portion 36b is a drive head that is used when the magnetic tape 1 is running in the opposite direction (direction A2 in FIG. 6). Since the first drive head portion 36a and the second drive head portion 36b have basically the same configuration, the first drive head portion 36a will be described as a representative.
- the first drive head section 36 a has a head body 131 , two servo read heads 132 and a plurality of data write/read heads 133 .
- the servo read head 132 is configured to read the magnetic flux generated from the magnetic information recorded in the servo band s of the magnetic tape 1 by means of an MR element (MR: Magneto Resistive effect) or the like, thereby reproducing the servo signal. . That is, the servo signal is reproduced by reading the servo pattern 6 recorded on the servo band s by the servo read head 132 .
- MR Magneto Resistive effect
- the servo read heads 132 are provided on each side of the head body 131 in the width direction (the Y'-axis direction in FIG. 7).
- MR elements include anisotropic magneto resistive effect (AMR), giant magneto resistive effect (GMR), and tunnel magneto resistive effect (TMR). include.
- AMR anisotropic magneto resistive effect
- GMR giant magneto resistive effect
- TMR tunnel magneto resistive effect
- the distance between the two servo read heads 132 in the width direction (Y'-axis direction) is approximately the same as the distance between adjacent servo bands s on the magnetic tape 1, the details of which will be described later.
- the data write/read heads 133 are arranged at equal intervals along the width direction (Y'-axis direction). Also, the data write/read head 133 is arranged at a position sandwiched between the two servo read heads 132 .
- the number of data write/read heads 133 is, for example, about 20 to 40, but this number is not particularly limited.
- the data write/read head 133 includes a data write head 134 and a data read head 135 .
- the data write head 134 is configured to be able to record data signals on the data band d of the magnetic tape 1 by the magnetic field generated from the magnetic gap.
- the data read head 135 is configured to read the magnetic field generated from the magnetic information recorded in the data band d of the magnetic tape 1 with an MR element (MR: Magneto Resistive effect) or the like, thereby reproducing the data signal.
- MR elements include anisotropic magneto resistive effect (AMR), giant magneto resistive effect (GMR), and tunnel magneto resistive effect (TMR). include.
- the data write head 134 is arranged on the left side of the data read head 135 (on the upstream side when the magnetic tape 1 flows in the forward direction).
- the data write head 134 is arranged on the right side of the data read head 135 (on the upstream side when the magnetic tape 1 flows in the opposite direction).
- the data read head 135 can reproduce the data signal immediately after the data write head 134 writes the data signal on the magnetic tape 1 .
- FIG. 8 is a diagram showing a state when the first drive head section 36a is recording/reproducing data signals.
- the example shown in FIG. 8 shows the magnetic tape 1 running in the forward direction (direction A1).
- one of the two servo read heads 132 is one of the two servo bands s. Positioned on one servo band s, the servo pattern 6 on this servo band s is read. The other servo read head 132 of the two servo read heads 132 is positioned on the other servo band s of the two adjacent servo bands s and reads the servo pattern 6 on this servo band s.
- the control device 38 determines whether the servo read head 132 is accurately tracing the target servo trace line T (see FIG. 5).
- the first stripe group 61 and the second stripe group 62 in the servo pattern 6 are inclined in opposite directions with respect to the width direction (Y-axis direction). Therefore, in the upper servo trace line T, the distance in the longitudinal direction (X-axis direction) between the first stripe group 61 and the second stripe group 62 is relatively narrow. On the other hand, on the lower servo trace line T, the distance in the longitudinal direction (X-axis direction) between the first stripe group 61 and the second stripe group 62 is relatively wide.
- the servo read head 132 can detect the magnetic tape 1. It is possible to know the current position in the width direction (Y-axis direction).
- the control device 38 can determine whether the servo read head 132 is accurately tracing the intended servo trace line T based on the reproduced waveform of the servo pattern 6 . If the servo read head 132 does not accurately trace the target servo trace line T, the control device 38 moves the drive head 36 in the width direction (Y'-axis direction) to Adjust the position of 36. A method of measuring the servo trace line T traced by the servo read head 132 will be described later with reference to FIG.
- the data write/read head 133 adjusts its position along the servo trace line T to produce a data signal in the recording track 5. record.
- the magnetic tape 1 is completely pulled out from the tape cartridge 10, this time the magnetic tape 1 is run in the reverse direction (direction A2).
- the second drive head portion 36b is used as the servo trace line T.
- the servo trace line T the servo trace line T adjacent to the previous servo trace line T is used.
- the data signal is recorded on the recording track 5 adjacent to the recording track 5 on which the data signal was previously recorded.
- data signals are recorded on the recording tracks 5 while the magnetic tape 1 is reciprocated many times by changing the running direction between the forward and reverse directions.
- the number of servo trace lines T is 50 and the number of data write/read heads 133 included in the first drive head section 36a (or the second drive head section 36b) is 32.
- FIG. 9 is a front view showing a servo pattern recording device 100 according to one embodiment of the present technology.
- FIG. 10 is a partially enlarged view showing a part of the servo pattern recording device 100.
- the servo pattern recording device 100 includes a feed roller 111, a preprocessing section 112, a servo write head 113, a read head section 114, and a take-up roller 115 in order from the upstream side in the transport direction of the magnetic tape 1.
- the servo pattern recording apparatus 100 further includes a driving section 120 and a controller 130.
- FIG. The controller 130 includes a control unit that generally controls each unit of the servo pattern recording apparatus 100, a recording unit that stores various programs and data necessary for the processing of the control unit, a display unit that displays data, and a data input unit. It has an input part etc.
- the delivery roller 111 can rotatably support the roll-shaped magnetic tape 1 (before the servo pattern 6 is recorded).
- the delivery roller 111 is rotated by a driving source such as a motor, and delivers the magnetic tape 1 downstream according to the rotation.
- the take-up roller 115 can rotatably support the roll-shaped magnetic tape 1 (after recording the servo pattern 6).
- the take-up roller 115 rotates in synchronization with the feed roller 111 when driven by a drive source such as a motor, and winds the magnetic tape 1 on which the servo patterns 6 are recorded according to the rotation.
- the delivery roller 111 and the take-up roller 115 are capable of moving the magnetic tape 1 at a constant speed on the transport path.
- the servo write head 113 is arranged, for example, above the magnetic tape 1 (on the side of the magnetic layer 43).
- the servo write head 113 may be arranged below the magnetic tape 1 (on the substrate 41 side).
- the servo write head 113 generates a magnetic field at a predetermined timing in response to the square wave pulse signal, and applies the magnetic field to a portion of the magnetic layer 43 (after pretreatment) of the magnetic tape 1 .
- the servo write head 113 magnetizes part of the magnetic layer 43 in the first direction to record the servo pattern 6 on the magnetic layer 43 (see the black arrow in FIG. 10 for the magnetization direction).
- the servo write head 113 is capable of recording servo patterns 6 on each of the five servo bands s0 to s4 when the magnetic layer 43 passes under the servo write head 113.
- the first direction which is the magnetization direction of the servo pattern 6 , includes a vertical component perpendicular to the upper surface of the magnetic layer 43 . That is, in the present embodiment, the magnetic layer 43 contains perpendicularly oriented or non-oriented magnetic powder, so the servo pattern 6 recorded on the magnetic layer 43 includes a perpendicular magnetization component.
- the preprocessing unit 112 is arranged, for example, on the upstream side of the servo write head 113 and below the magnetic tape 1 (on the substrate 41 side).
- the preprocessing section 112 may be arranged above the magnetic tape 1 (on the magnetic layer 43 side).
- the preprocessing section 112 includes a permanent magnet 112a rotatable about the Y-axis direction (the width direction of the tape 1) as the central axis of rotation.
- the shape of the permanent magnet 112a is, for example, cylindrical or polygonal, but not limited thereto.
- the permanent magnet 112a Before the servo pattern 6 is recorded by the servo write head 113, the permanent magnet 112a applies a magnetic field to the entire magnetic layer 43 by a DC magnetic field to demagnetize the entire magnetic layer 43.
- FIG. 10 As a result, the permanent magnet 112a can previously magnetize the magnetic layer 43 in the second direction opposite to the magnetization direction of the servo pattern 6 (see the white arrow in FIG. 10).
- the reproduced waveform of the servo signal obtained by reading the servo pattern 6 can be made symmetrical in the vertical direction ( ⁇ ).
- the rotation angle of the permanent magnet 112a is arbitrary, the entire magnetic layer 43 is demagnetized, the servo pattern 6 is recorded on the magnetic layer 43, and the gradient of the reproduced waveform is Based on this, the rotation angle of the permanent magnet 112a about the width direction of the magnetic tape 1 may be adjusted.
- the reproducing head unit 114 is arranged downstream of the servo write head 113 and above the magnetic tape 1 (magnetic layer 43 side).
- the reproducing head unit 114 reads the servo pattern 6 from the magnetic layer 43 of the magnetic tape 1 which has been preprocessed by the preprocessing unit 112 and recorded with the servo pattern 6 by the servo write head 113 .
- a reproduced waveform of the servo pattern 6 read by the reproducing head unit 114 is displayed on the screen of the display unit.
- the read head section 114 detects magnetic flux generated from the surface of the servo band s when the magnetic layer 43 passes under the read head section 114 . The magnetic flux detected at this time becomes a reproduction waveform of the servo pattern 6 as a servo signal.
- FIG. 11(A) is a diagram showing the data structure of the LPOS word embedded in the servo pattern 6, and FIG. 11(B) is a diagram explaining the manufacturer word.
- the servo pattern 6 is embedded with a plurality of LPOS (Longitudinal Position) words LW arranged continuously in the longitudinal direction of the tape.
- LPOS word LW includes an 8-bit synchronization mark Sy indicating its head, an LPOS value Ls consisting of 6 4-bits (24 bits in total) indicating a position (address) in the longitudinal direction of the tape, and a 4-bit manufacture It is composed of 36-bit data including trader data Tx.
- the manufacturer data Tx form a manufacturer word TW on the magnetic tape 1.
- FIG. The manufacturer word TW has a length of 97 manufacturer data Tx, as shown in FIG. 11B, and is obtained by successively reading 97 LPOS words LW.
- the manufacturer word TW is constructed as follows. Manufacturer word TW: D, A0, A1, A0, A1, ..., A0, A1
- D which is the first manufacturer data Tx, is a symbol indicating the beginning of the manufacturer word TW, and includes 4-bit data (typically "0001") converted by a predetermined table. ”) is written.
- the second and subsequent 96 manufacturer data Tx consist of "A0" and “A1” alternately arranged, and two adjacent "A0” and “A1” form a set of symbol pairs.
- Each symbol pair “A0” and “A1” contains any 13 base symbols other than "D" (typically 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 , A, B, and C) are written respectively.
- These 13 basic symbols also consist of 4-bit data converted by the above predetermined table. Then, one symbol (hereinafter also referred to as LPOS recorded value) determined according to a combination of two specific basic symbols (corresponding to the symbol pair) among the 13 basic symbols is specified.
- the LPOS record value consists of 8-bit data.
- the two base symbols forming a symbol pair may be a homogeneous combination (eg 0,0) or a heterogeneous combination (eg 0,1).
- the 96 pieces of manufacturer data Tx configured as described above typically include manufacturer information represented by LPOS recording values, management information such as the manufacturing date and serial number of the magnetic tape, and servo band information. Servo band identification information for identification is embedded.
- FIG. 12(A) is a schematic plan view showing an arrangement example of the servo pattern 6, and FIG. 12(B) is a diagram showing its reproduced waveform.
- the servo pattern includes a plurality of azimuthal slope patterns of two or more different shapes.
- the position of the servo read head 132 is recognized based on the time interval between reading two tilt patterns with different shapes and the time interval between reading two tilt patterns with the same shape. Based on the position of the servo read head 132 thus recognized, the position of the drive head 36 in the width direction (Y-axis direction) of the magnetic tape 1 is controlled (see FIGS. 7 and 8).
- the servo pattern 6 forms a servo frame SF having a first servo sub-frame SSF1 and a second servo sub-frame SSF2.
- the servo frames SF are arranged continuously at predetermined intervals along the longitudinal direction of the tape.
- Each servo frame SF encodes one bit of '1' or '0'. That is, one servo frame SF corresponds to one bit.
- the first servo subframe SSF1 is composed of an A burst 6a and a B burst 6b.
- the A burst 6a is composed of five linear patterns (corresponding to the first stripe group 61 in FIG. 5) inclined in the first direction with respect to the longitudinal direction of the tape
- the B burst 6b is composed of the above-mentioned first stripes in the longitudinal direction of the tape. It consists of five linear patterns (corresponding to the second stripe group 62 in FIG. 5) inclined in the second direction opposite to the first direction.
- the second servo subframe SSF2 is composed of a C burst 6c and a D burst 6d.
- the C burst 6c is composed of four linear patterns (corresponding to the first stripe group 61 in FIG. 5) inclined in the first direction
- the D burst 6d is composed of four linear patterns inclined in the second direction. It consists of a linear pattern (corresponding to the second stripe group 62 in FIG. 5).
- the length of the servo frame SF and the servo subframes SSF1 and SSF2, the arrangement interval of the inclined portions that incline the bursts 6a to 6d, etc. can be arbitrarily set according to the type and specifications of the magnetic tape.
- the reproduction waveform of the servo pattern 6 typically exhibits a burst waveform as shown in FIG.
- Signal S6d corresponds to D burst 6d.
- a position error signal is generated by reading servo patterns 6 on two servo bands adjacent to one data band, and Properly position the read/write head relative to the recording track.
- the servo pattern 6 is read from the magnetic tape 1 running at a predetermined speed, and the distance (time interval) AC between the A burst 6a and the C burst 6c, which are arrays of inclined patterns of the same type, and The ratio of the distance (time interval) AB between the A burst 6a and the B burst 6b, which are arrays of different-shaped gradient patterns (or the distance CA between the C burst 6c and the A burst 6a, and the C burst 6c and the distance CD to the D burst 6d) is calculated, and the drive head 36 is moved in the tape width direction (Y-axis direction) so that the value becomes the set value determined for each recording track (Fig. 8 reference).
- Servo band identification information Different combinations of servo band identification information are written for each data band in each servo band s (s0 to s4).
- a combination of servo band identification information obtained from two servo bands s2 and s3 adjacent to data band d0 is a combination of servo band identification information obtained from servo bands s1 and s2 adjacent to data band d1 and data band
- the combination of servo band identification information obtained from servo bands s3 and s4 adjacent to data band d2 is different from the combination of servo band identification information obtained from two servo bands s0 and s1 adjacent to data band d3.
- the servo band identification information is embedded in the servo band.
- the servo band identification information is information of multiple bits, and is embedded in predetermined positions of the second and subsequent 96 pieces of manufacturer data Tx in the manufacturer word TW.
- the servo band identification information is typically 4 bits, but may be 8 bits (combination of symbol pair "A0" and "A1"), or other multiple bits than 4 bits and 8 bits. may be
- the two types of servo bands include a first servo band in which first servo band identification information is recorded and a second servo band in which second servo band identification information is recorded.
- the first servo band identification information is 4-bit information (eg, "1001")
- the second servo band identification information is 4-bit information (eg, "0111") different from the first servo band identification information. ).
- a combination of codes "0" and “1" forming the first and second servo band identification information is identified from the reproduced waveform of the servo pattern 6. That is, the reproduced waveform of the servo pattern 6 corresponds to modulated waves of codes "0" and "1". Information is read.
- the first and second servo band identification information will be described below with reference to FIGS. 13 and 14. FIG.
- both the first servo pattern 601 and the second servo pattern 602 represent a servo frame SF1 representing one code (for example, "1") and the other code (for example, "0"). It consists of a combination of two types of servo frames SF including the servo frame SF0 shown.
- Each of the servo frames SF1 and SF0 is common in that the servo frame SF consisting of the first servo sub-frame SSF1 and the second servo sub-frame SSF2 is a constituent unit, but the first servo sub-frame SSF1 (the A burst 6a and the B burst 6b) are different from each other.
- the five tilt patterns forming the A burst 6a and the B burst 6b are arranged in order from the left side of the drawing, the first tilt portion, the When the second inclined portion, the third inclined portion, the fourth inclined portion, and the fifth inclined portion are provided, the second and fourth inclined portions are arranged at positions biased toward the first and fifth inclined portions, respectively.
- the servo frame SF0 representing the code "0"
- part of the tilt patterns forming the A burst 6a and the B burst 6b are arranged at intervals different from those of the servo frame SF1. different.
- the five slanted patterns forming the A burst 6a and the B burst 6b are arranged such that the second and fourth slanted portions are biased toward the third slanted portion. Therefore, for the A burst 6a and the B burst 6b in the servo frame SF0, the distances between the second and third slopes and between the third and fourth slopes are the smallest, and the distances between the first and fourth slopes are the smallest. The distance between the second inclined portion and the fourth and fifth inclined portions is the largest.
- the reproduced waveforms of the servo frames SF1 and SF0 are composed of burst signals having peaks at positions corresponding to the slopes of the burst portions 6a to 6d.
- the configurations of the A burst 6a and the B burst 6b are different from those of the servo frame SF1.
- a shift occurs in the peak position of S6b. Therefore, the information written in the servo frame SF can be read by detecting the portion where the peak position is shifted, the amount of the shift, and the direction of the shift.
- the servo frame SF1 shown in FIG. 14A represents one bit "1”
- the servo frame SF0 shown in FIG. 14B represents another one bit "0”.
- the servo pattern recording apparatus 100 has a drive unit 120 that drives the servo write head 113, as shown in FIG.
- FIG. 15 is a perspective view schematically showing the configuration of the servo write head 113
- FIG. 16 is a block diagram showing the configuration of the driving section 120. As shown in FIG.
- the servo write head 113 has a plurality of head blocks h0-h4 for recording the servo pattern 6 on each servo band s0-s4 of the magnetic tape 1.
- FIG. Each head block h0-h4 is joined to each other via an adhesive layer hs.
- Each of the head blocks h0-h4 constitutes a recording section arranged corresponding to each servo band s0-s4 of the magnetic tape 1, and has a magnetic gap g for recording a servo pattern in each servo band.
- the magnetic gap g consists of a pair of straight portions ("/" and “ ⁇ ") inclined in opposite directions, one straight portion "/" for A burst 6a and C burst 6c, ⁇ ” records B burst 6b and D burst 6d respectively.
- the magnetic gaps g of the head blocks h1 to h5 are arranged so as to align on an axis parallel to the longitudinal direction of the servo write head 113.
- Each of the head blocks h0 to h4 is magnetically separated from each other, and is configured to be capable of simultaneously recording different types of servo patterns 6 on two or more servo bands.
- the driving unit 120 includes a converter 121 that converts servo information into pulse information based on the output from the controller 130 (see FIG. 9), and generates a pulse signal based on the output of the converter 121. and an amplifier 123 for amplifying the generated pulse signal.
- a plurality of signal generators 122 and amplifiers 123 are provided corresponding to each of the head blocks h0 to h4, and are configured to be capable of outputting pulse signals specific to the head blocks h0 to h4 of each servo write head 113. be done.
- the controller 130 determines the position of the servo band (s0, s1, s4 in this example) where the first servo band identification information is to be recorded and the position of the servo band (in this example) where the second servo band identification information is to be recorded. Then, a memory storing data relating to s2, s3) is provided. Controller 130 controls drive unit 120 based on the data stored in the memory.
- the converter 121 individually outputs information corresponding to servo band identification information to be recorded in each of the servo bands s0 to s4 to the signal generators 122 corresponding to each of the head blocks h0 to h4.
- a first servo pattern 601 (FIG. 13A) including first servo band identification information is recorded in head blocks h0, h1 and h4 corresponding to servo bands s0, s1 and s4.
- FIGS. 17A and 17B schematically show recording signal waveforms of the first servo sub-frame SSF1 in the first pulse signal PS1 and the second pulse signal PS2, respectively.
- the first and second pulse signals PS1 and PS2 include a first pulse group SPF1 consisting of five pulse groups and a second pulse group SPF2 consisting of four pulse groups.
- the first pulse group SPF1 is a signal for recording each slope of the A burst 6a
- the second pulse group SPF2 is a signal for recording each slope of the B burst 6b.
- the rising times of the second and fourth pulses in the first pulse group SPF1 are different between the first pulse signal PS1 and the second pulse signal PS2.
- the rising time of the second pulse is later than that of the pulse signal PS1, and the rising time of the fourth pulse is earlier.
- the first servo sub-frames SSF1 are formed, as shown in FIGS. 13A and 13B, in which the arrangement intervals of the inclined portions of the A bursts 6a are partially different.
- the first pulse signal PS1 and the second pulse signal PS2 are transmitted to the head blocks h0 to h4 with the same phase (same timing).
- the servo bands s0, s1 and s4 have the first servo pattern 601 (first servo band identification information), and the servo bands s2 and s3 have the second servo pattern 602 ( second servo band identification information) is recorded in phase.
- the magnetic tape 1 is generally manufactured by applying a magnetic material to a base film (substrate 41), calendering, cutting, recording the servo patterns 6, and the like. Since these treatments are performed while the base film is being wound with a constant tension, the completed magnetic tape 1 has internal strain, and the width of the magnetic tape 1 tends to widen with the passage of time. Also, the higher the temperature or humidity of the storage environment of the magnetic tape 1, the wider the width of the tape. Furthermore, in the magnetic tape 1 wound around the tape reel 13 of the tape cartridge 10, a higher winding pressure is applied to the inner peripheral side of the tape reel 13 than to the outer peripheral side, so the tape width is wider than that to the outer peripheral side. There is a tendency. In particular, recent magnetic tapes, which require high capacity, are becoming thinner due to the reduction in base film thickness and coating thickness. The influence of dimensional variations becomes more and more pronounced.
- the width of the magnetic tape is the same as the width of the magnetic tape when recording the servo pattern. It may increase more than the dimension.
- the intervals between adjacent servo bands change, the intervals between the servo patterns recorded in these servo bands also fluctuate. As a result, desired tracking control becomes difficult. Such a problem can occur significantly due to the thinning of magnetic tapes accompanying the recent increase in recording capacity.
- the "ECMA-319 standard” defines the arrangement interval (servo band pitch) of the servo bands s, which is 2858.8 ⁇ m ⁇ 4.6 ⁇ m.
- the first pitch P1 (see FIG. 7), which is the arrangement interval between the two servo read heads 132 in the drive head 36, is the center of the standard value of the servo band pitch. value (2858.8 ⁇ m).
- the first pitch P1 is the distance between the centers of the two servo read heads 132 in the tape width direction.
- the servo write head 113 in the servo pattern recording device 100 has a plurality of magnetic gaps g (see FIG. 15) for recording the servo pattern 6 on each servo band s of the magnetic tape 1.
- FIG. 15 Each magnetic gap g is arranged at a second pitch P2, which is a constant interval, as shown in FIG.
- the second pitch P2 is the distance between the centers of the pattern width Pw in the tape width direction of two adjacent magnetic gaps g.
- the second pitch P2 is the same value as the first pitch P1 (2858.8 ⁇ m)
- variations in the width dimension of the magnetic tape 1 may cause the servo pattern 6 to be formed by the servo read head 132 of the tape drive device 30.
- the trace position may deviate from the center value of the pattern width Pw of the servo pattern 6 .
- the servo band pitch of a magnetic tape on which a servo pattern is recorded using a servo write head in which the second pitch P2 is the same value as the first pitch P1 is measured by two servo read heads 132 of the tape drive device 30.
- FIG. 19 shows the experimental results measured using this method.
- the magnetic tape 1 is run by the tape drive device 30, the servo trace lines T on each servo band of the two servo read heads 132 are measured, and each measured servo trace line T is measured. , the servo band pitch is measured from the relative position to the servo pattern 6 .
- the servo band pitch of the magnetic tape 1 is the same as the first pitch P1
- the servo trace line T of one servo read head 132 should be positioned at the center of the servo pattern 6 on one servo band.
- the servo trace line T of the other servo read head 132 is also positioned at the center of the servo pattern 6 on the other servo band.
- the servo band pitch of the magnetic tape 1 will have a value different from the first pitch P1.
- the difference between the measured values of each servo trace line T is taken. shall be
- the abscissa is the inner peripheral edge of the magnetic tape 1 wound around the tape reel 13 from the outer peripheral edge (hereinafter also referred to as BOT) of the magnetic tape 1 wound around the tape reel 13 .
- the length to the end (hereinafter also referred to as EOT) is defined as about 1000 m here.
- the vertical axis represents the servo band pitch obtained from the servo signal, which is the reproduction signal of the servo pattern, and shows the amount of deviation from the first pitch P1. Therefore, the center value "0 ⁇ m" means that the difference between the servo trace lines T is zero, and corresponds to the first pitch P1 (the same applies to FIGS. 20 and 21 described later).
- the tension during tape running was set to 0.55 N both during servo pattern recording and during servo pattern reproduction.
- TA1 in the figure is the measurement value for the magnetic tape of the tape cartridge immediately after production
- TB1 is the magnetic tape of the tape cartridge stored for one week in a constant temperature chamber at 29 ⁇ 2° C. and 80 ⁇ 5% RH. is a measurement value for
- the magnetic tape TA1 immediately after production had a substantially constant servo band pitch over its entire length, and the value was slightly wider than the center value. This is thought to be due to the fact that although the tape width slightly decreased due to the tension during tape running, the tape width turned to increase due to the relaxation of the internal strain of the magnetic tape TA1.
- the amount of tape width expansion increases, and in particular, the tape width tends to gradually expand from BOT to EOT. This is considered to be the result of the swelling of the magnetic tape and the effect of the winding pressure of the tape under the high-temperature and high-humidity environment.
- the magnetic tape TB cannot trace the recording track in a length area of about 500 m or more from the EOT. , means that stable recording/reproducing accuracy cannot be obtained.
- the pattern pitch (second pitch P2, see FIG. 18) of the servo write head 113 is the arrangement interval of the two servo read heads 132 in the tape drive device 30. It is formed narrower than the first pitch P1. That is, while the magnetic tape 1 is running at a predetermined tension, the plurality of servo bands s are arranged at a second pitch P2 narrower than the first pitch P1, which is the arrangement interval between the two servo read heads 132 in the tape drive device 30. , the servo pattern 6 is recorded.
- TA2 is the measured value for the magnetic tape of the tape cartridge immediately after production
- TB2 is the measured value for the magnetic tape of the tape cartridge stored for one week in a constant temperature chamber at 29 ⁇ 2° C. and 80 ⁇ 5% RH. It is a measured value.
- the magnetic tape TA2 immediately after production but also the magnetic tape TB2 stored under predetermined conditions can have the servo band pitch within the readable range of the tape drive device 30 over its entire length. This enables stable tracking control over the entire length of the tape, so that desired high-precision data recording and reproduction can be realized.
- the magnetic layer 43 of the magnetic tape 1 has two servo read heads 132 arranged thereon. It has a first region having a servo band pitch narrower than the first pitch P1, which is the spacing, and a second region having a servo band pitch wider than the first pitch P1.
- the first area is the area on the BOT side
- the second area is the area on the EOT side.
- the servo band pitch of the magnetic layer 43 tends to gradually widen from the BOT side to the EOT side.
- the tape length located at the boundary between the first area and the second area is preferably, for example, 200 m or more and 400 m or less from the BOT, and was about 300 m in the example of FIG.
- the servo band pitch of the magnetic tape 1 measured by the tape drive device 30 can also vary depending on the magnitude of the tension during recording of the servo pattern 6 .
- FIG. 21 shows experimental results showing the tension effect during servo pattern recording.
- TA3 is the measured value immediately after manufacturing the magnetic tape with a running tension of 0.3 N during servo pattern recording
- TA4 is the measured value immediately after manufacturing the magnetic tape with a running tension of 0.6 N during servo pattern recording. is the measured value.
- the running tension during reproduction of the servo signal by the tape drive device 30 was set to 0.55 N as described above.
- the lower the tape tension during servo pattern recording than the tape tension during data recording/reproduction the narrower the servo band pitch.
- the servo band pitch changes in the widening direction (see the measurement results of TA2 and TA4). This indicates that the servo band pitch of the magnetic tape 1 measured by the tape drive device 30 can also be controlled by the tape tension in the servo pattern recording device 100 .
- the tape tension in the servo pattern recording device 100 can be arbitrarily set according to the tape tension in the tape drive device 30, the recording track width Wd of the data band, and the like.
- the tape tension in the servo recording device 100 can be 0.3N or more and 0.6N or less. That is, the servo band pitch can also be adjusted by adjusting the tape tension when writing the servo pattern 6 by the servo pattern recording device 100 .
- the value is particularly It is not limited, and can be arbitrarily adjusted depending on the type of the magnetic tape 1 (for example, the thickness of the base material 41).
- the difference of the first pitch with respect to the second pitch P2 is 5 ⁇ m or less. More preferably, when the first pitch P1 is 2858.8 ⁇ m, the second pitch P2 is 2854.2 ⁇ m or more and 2858.7 ⁇ m or less.
- the magnetic tape 1 is developed using a magnetic colloid solution such as the developer "Sigma Marker Q” manufactured by Sigma High Chemical Co., Ltd. as a ferric colloid developer, and servo patterns 6 recorded in two adjacent servo bands are obtained.
- the servo band pitch is calculated by measuring the interval between the center positions of the developed patterns.
- the tape drive device 30 can be used to measure the servo band pitch.
- the drive head 36 tracks the data band d0 sandwiched between the servo band s2 and the servo band s3 will be described.
- the method of measuring the servo band pitch using the tape drive device 30 consists of running the magnetic tape 1 by the tape drive device 30 and measuring the servo trace lines T on each servo band of the two servo read heads 132 as described above.
- the servo band pitch is measured from the relative position of each measured servo trace line T with respect to the servo pattern 6 .
- the interval between the servo trace lines T indicated by solid lines in FIG. 22 is the servo band pitch when the width of the magnetic tape 1 does not change (the first pitch P1 which is the arrangement interval between the two servo read heads 132 of the drive head 36). ). 22 corresponds to the servo band pitch (P2') when the width of the magnetic tape 1 is widened.
- FIG. 23A and 23B are diagrams for explaining a method of measuring the servo trace line T.
- FIG. The tape drive device 30 outputs a servo reproduction signal having a waveform corresponding to the position of the servo trace line T with respect to the servo pattern 6 (see FIG. 19).
- a distance AC between A bursts and C bursts, which are arrays of gradient patterns of the same shape, and a distance AB between A bursts and B bursts, which are arrays of gradient patterns of different shapes are calculated.
- the position of the servo trace line T of each servo read head 132 is measured by the following formula (1).
- .theta. is the azimuth angle of each tilt pattern corresponding to the angle .alpha. in FIG. 5, and is 12.degree. in this example.
- the distance AC may be the distance AC1 between the first slopes of the A burst and the C burst, the distance AC2 between their second slopes, or the distance AC2 between their second slopes. may be the distance AC3 between them, or the distance AC4 between the fourth inclined portions.
- These distances AC (AC1 to AC4) refer to the distances between the positions (upper peak positions) showing the maximum positive amplitude values in the servo reproduction waveform.
- the distance AB may be the distance AB1 between the first sloped portions of the A burst and the B burst, the distance AB2 between the second sloped portions thereof, or the third sloped portions thereof. may be the distance AB3 between them, or the distance AB4 between the fourth inclined portions.
- distance AB1 is adopted when distance AC1 is adopted
- distance AB2 is adopted when distance AC2 is adopted
- distance AB3 is adopted when distance AC3 is adopted
- distance AC4 is adopted. If adopted, the distance AB4 is adopted.
- the servo band pitch is obtained from the difference between the numerical values representing the positions of the servo trace lines T on the servo pattern obtained from the ratio of the distance AB and the distance AC calculated using the formula [Equation 1].
- the difference in the measured value of the tape center side servo band (servo band s2) from the measured value of the tape edge side servo band (servo band s3) is taken.
- the positive or negative of the value means the direction of change in the tape width.
- a positive value corresponds to narrowing of the servo band pitch, and a negative value corresponds to widening of the servo band pitch. If the difference is zero, it means that there is no change in tape width.
- the servo band pitch is preferably obtained from the differences of a large number of servo frames, and may be the average value of the measured values calculated from the differences of 100 to 100000 servo frames, for example.
- the tape tension during measurement is set to 0.55 N, and the measurement is performed with a constant tension over the entire length of the magnetic tape 1 .
- the method of measuring the servo trace line T is not limited to the above example.
- the distance CA between the C burst and the A burst and the distance CD between the C burst and the D burst are calculated, , the position of the servo trace line T may be measured.
- the distance CA may be the distance CA1 between the first sloped portions of the C burst and the A burst, the distance CA2 between the second sloped portions thereof, or the third sloped portions thereof. may be the distance CA3 between them, or the distance CA4 between the fourth inclined portions.
- These distances CA (CA1 to CA4) refer to the distances between positions showing the maximum positive amplitude values in the servo reproduction waveform.
- the distance CD may be the distance CD1 between the first sloped portions of the C burst and the D burst, the distance CD2 between the second sloped portions thereof, or the third sloped portions thereof. may be the distance CD3 between them, or the distance CD4 between the fourth inclined portions.
- the distance CD1 is adopted when the distance CA1 is adopted
- the distance CD2 is adopted when the distance CA2 is adopted
- the distance CD3 is adopted when the distance CA3 is adopted
- the distance CA4 is adopted. If adopted, the distance CD4 is adopted.
- the average value of the measured value using the formula (1) and the measured value using the formula (2) may be used.
- the distances between the positions (lower peak positions) indicating the maximum negative amplitude values in the servo reproduction waveform are employed as the distances AC and AB in the formula [Formula 1] and the distances CA and CD in the formula [Formula 2]. good too.
- the distance between the positions (upper peak positions) indicating the maximum positive value of the amplitude in the servo reproduction waveform and the maximum negative value An average value of distances between positions (lower peak positions) indicating values may be adopted.
- the distance AB is 38.5 ⁇ m and the distance AC is 76 ⁇ m in the servo band s2, and the distance AB is 37.5 ⁇ m and the distance AC is 37.5 ⁇ m in the servo band s3.
- In servo band s2, (38.5/76) ⁇ (76/2tan12°) 90.5641 [ ⁇ m]
- In servo band s3, (37.5/76) ⁇ (76/2tan12°) 88.2118 [ ⁇ m] becomes.
- both the servo band s2 and the servo band s3 have a servo band pitch of 89.3880 [ ⁇ m] and a difference therebetween of 0 [ ⁇ m].
- the servo pattern 6 is recorded on the magnetic tape 1 using the servo write head 113 having the magnetic gap g arranged at the second pitch P2 narrower than the first pitch P1.
- the magnetic tape 1 manufactured in this manner at least one region (first region, see FIG. 20) in which the servo pattern pitch, which is the distance between two adjacent servo bands, is narrower than the first pitch P1 is formed. present in the department.
- the first area is distributed unevenly in the area on the BOT side as described above.
- the difference between the servo pattern pitch and the first pitch P1 in the first area is, for example, 0.1 ⁇ m or more and 4.6 ⁇ m or less, preferably 0.5 ⁇ m or more and 4.6 ⁇ m or less.
- the lower limit of 0.1 ⁇ m of the difference means, for example, 0.1 ⁇ m narrower than the first pitch P1 and the central value of 2858.8 ⁇ m of the ECMA-319 standard.
- the upper limit of 4.6 ⁇ m of the difference means, for example, 2854.2 ⁇ m, which is the lower limit of the “ECMA-319 standard”.
- the lower limit value and upper limit value of the difference are dimensions for correcting the spread of the servo pattern pitch on the tape due to future changes over time. This enables stable tracking control of the drive head 36 over the entire length of the tape, and ensures desired data recording/reproducing accuracy.
- the magnetic tape 1 has a long tape shape, and is run in the longitudinal direction during recording and reproduction.
- the surface of the magnetic layer 43 is the surface on which the magnetic head of the recording/reproducing device (not shown) runs.
- the magnetic tape 1 is preferably used in a recording/reproducing apparatus having a ring head as a recording head.
- the magnetic tape 1 is preferably used in a recording/reproducing apparatus capable of recording data with a data track width of 1500 nm or less or 1000 nm or less.
- the substrate 41 is a non-magnetic support that supports the underlying layer 42 and the magnetic layer 43 .
- the base material 41 has a long film shape.
- the upper limit of the average thickness of the base material 41 is preferably 4.2 ⁇ m or less, more preferably 4.0 ⁇ m or less, still more preferably 3.8 ⁇ m or less, and most preferably 3.4 ⁇ m or less.
- the lower limit of the average thickness of the base material 41 is preferably 3 ⁇ m or more, more preferably 3.2 ⁇ m or more. When the lower limit of the average thickness of the base material 41 is 3 ⁇ m or more, a decrease in the strength of the base material 41 can be suppressed.
- the average thickness of the base material 41 is obtained as follows. First, a magnetic tape 1 having a width of 1/2 inch is prepared and cut into a length of 250 mm to prepare a sample. Subsequently, layers other than the base material 41 of the sample (that is, the underlayer 42, the magnetic layer 43 and the back layer 44) are removed with a solvent such as MEK (methyl ethyl ketone) or dilute hydrochloric acid. Next, using a Mitutoyo laser hologram (LGH-110C) as a measuring device, the thickness of the sample (substrate 41) is measured at five or more points, and the measured values are simply averaged (arithmetic average ) to calculate the average thickness of the base material 41 . It is assumed that the measurement position is randomly selected from the sample.
- a Mitutoyo laser hologram LGH-110C
- the base material 41 preferably contains polyester. Since the base material 41 contains polyester, the Young's modulus of the base material 41 in the longitudinal direction can be reduced. Therefore, the width of the magnetic tape 1 can be kept constant or substantially constant by adjusting the tension in the longitudinal direction of the magnetic tape 1 during running with the recording/reproducing device.
- the Young's modulus of the substrate 41 in the longitudinal direction is, for example, 5 GPa or more and 10 GPa or less, preferably 2.5 GPa or more and 7.8 GPa or less, more preferably 3.0 GPa or more and 7.0 GPa or less.
- Polyesters are, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polycyclohexylene dimethylene terephthalate (PCT), polyethylene-p-oxybenzoate ( PEB) and at least one of polyethylene bisphenoxycarboxylate.
- PET polyethylene terephthalate
- PEN polyethylene naphthalate
- PBT polybutylene terephthalate
- PBN polybutylene naphthalate
- PCT polycyclohexylene dimethylene terephthalate
- PEB polyethylene-p-oxybenzoate
- at least one of the terminal and the side chain of the polyester may be modified.
- polyester in the base material 41 can be confirmed, for example, as follows. First, similar to the method for measuring the average thickness of the base material 41, the magnetic tape 1 is prepared and cut into a length of 250 mm to prepare a sample. Next, an IR spectrum of the sample (base material 41) is obtained by infrared absorption spectrometry (IR). Based on this IR spectrum, it can be confirmed that the base material 41 contains polyester.
- IR infrared absorption spectrometry
- the base material 41 may contain at least one of polyamide, polyetheretherketone, polyimide, polyamideimide, and polyetheretherketone (PEEK), in addition to polyester, and may include polyamide, polyimide, and polyamideimide. , polyolefins, cellulose derivatives, vinyl resins, and other polymeric resins.
- the polyamide may be an aromatic polyamide (aramid).
- the polyimide may be an aromatic polyimide.
- the polyamideimide may be an aromatic polyamideimide.
- the base material 41 when the base material 41 contains polymer resin other than polyester, the base material 41 preferably contains polyester as the main component.
- the main component means the component with the highest content (mass ratio) among the polymer resins contained in the base material 41 .
- the polyester and the polymer resin other than polyester may be mixed or copolymerized.
- the base material 41 may be biaxially stretched in the longitudinal direction and the width direction.
- the polymer resin contained in the base material 41 is preferably oriented obliquely with respect to the width direction of the base material 41 .
- the magnetic layer 43 is a recording layer for recording signals by magnetization patterns.
- the magnetic layer 43 may be a perpendicular recording type recording layer or a longitudinal recording type recording layer.
- the magnetic layer 43 contains, for example, magnetic powder, binder and lubricant.
- the magnetic layer 43 may further contain at least one additive selected from antistatic agents, abrasives, hardeners, rust preventives, non-magnetic reinforcing particles, and the like, if necessary.
- the magnetic layer 43 is not limited to being composed of a coated film of a magnetic material, and may be composed of a sputtered film or vapor-deposited film of a magnetic material.
- the arithmetic mean roughness Ra of the surface of the magnetic layer 43 is 2.0 nm or less, preferably 1.8 nm or less, more preferably 1.6 nm or less. When the arithmetic mean roughness Ra is 2.0 nm or less, it is possible to suppress the decrease in output due to the spacing loss, so excellent electromagnetic conversion characteristics can be obtained.
- the lower limit of the arithmetic mean roughness Ra of the surface of the magnetic layer 43 is preferably 1.0 nm or more, more preferably 1.2 nm or more. When the lower limit of the arithmetic mean roughness Ra of the surface of the magnetic layer 43 is 1.0 nm or more, it is possible to suppress deterioration in running performance due to an increase in friction.
- the arithmetic mean roughness Ra is obtained as follows. First, the surface of the magnetic layer 43 is observed with an AFM (Atomic Force Microscope) to obtain an AFM image of 40 ⁇ m ⁇ 40 ⁇ m.
- the AFM is Nano Scope IIIa D3100 manufactured by Digital Instruments, the cantilever is made of silicon single crystal (Note 1), and the tapping frequency is tuned at 200 to 400 Hz.
- the average height (average surface) Zave ( (Z (1) + Z (2) + ... + Z ( 262, 144))/262, 144).
- the upper limit of the average thickness t m of the magnetic layer 43 is 80 nm or less, preferably 70 nm or less, more preferably 50 nm or less. If the upper limit of the average thickness t m of the magnetic layer 43 is 80 nm or less, the influence of the demagnetizing field can be reduced when a ring-type head is used as the recording head, so that even better electromagnetic conversion characteristics can be obtained. can.
- the lower limit of the average thickness t m of the magnetic layer 43 is preferably 35 nm or more. If the lower limit of the average thickness t m of the magnetic layer 43 is 35 nm or more, the output can be ensured when an MR head is used as the reproducing head, so that even better electromagnetic conversion characteristics can be obtained.
- the average thickness t m of the magnetic layer 43 is obtained as follows. First, the magnetic tape 1 accommodated in the cartridge 10 is unwound, and three samples are prepared by cutting the magnetic tape 1 at three positions of 10 m, 30 m, and 50 m from one end on the outermost circumference side. Subsequently, each sample (the magnetic tape 1 to be measured) is processed by the FIB method or the like to be thinned. When the FIB method is used, a carbon layer and a tungsten layer are formed as protective films as a pretreatment for observing a cross-sectional TEM image, which will be described later.
- the carbon layer is formed on the magnetic layer 43 side surface and the back layer 44 side surface of the magnetic tape 1 by vapor deposition, and the tungsten layer is further formed on the magnetic layer 43 side surface by vapor deposition or sputtering.
- the thinning is performed along the length direction (longitudinal direction) of the magnetic tape 1 . That is, by the thinning, a cross section parallel to both the longitudinal direction and the thickness direction of the magnetic tape 1 is formed.
- TEM transmission electron microscope
- the thickness of the magnetic layer 43 is measured at ten or more positions of each sliced sample.
- the ten measurement positions of each thinned sample are different positions in the longitudinal direction of the magnetic tape 1. randomly selected from.
- the average value obtained by simply averaging (arithmetic mean) the measured values of the obtained thinned samples (the thickness of the magnetic layer 43 at 30 points in total) is defined as the average thickness t m [nm] of the magnetic layer 43. do.
- Magnetic powder includes a plurality of magnetic particles.
- the magnetic particles are, for example, particles containing hexagonal ferrite (hereinafter referred to as “hexagonal ferrite particles”), particles containing epsilon-type iron oxide ( ⁇ iron oxide) (hereinafter referred to as “ ⁇ iron oxide particles”), or Co-containing particles. It is a particle containing spinel ferrite (hereinafter referred to as “cobalt ferrite particle”).
- the magnetic powder is preferably crystal-oriented preferentially in the thickness direction (perpendicular direction) of the magnetic tape 1 .
- the hexagonal ferrite particles have, for example, a plate shape such as a hexagonal plate shape or a columnar shape such as a hexagonal columnar shape (where the thickness or height is smaller than the major axis of the plate surface or bottom surface).
- the hexagonal slope shape includes a substantially hexagonal slope shape.
- the hexagonal ferrite preferably contains at least one of Ba, Sr, Pb and Ca, more preferably at least one of Ba and Sr.
- the hexagonal ferrite may in particular be, for example, barium ferrite or strontium ferrite. Barium ferrite may further contain at least one of Sr, Pb and Ca in addition to Ba.
- the strontium ferrite may further contain at least one of Ba, Pb and Ca in addition to Sr.
- hexagonal ferrite has an average composition represented by the general formula MFe 12 O 19 .
- M is, for example, at least one metal selected from Ba, Sr, Pb and Ca, preferably at least one metal selected from Ba and Sr.
- M may be a combination of Ba and one or more metals selected from the group consisting of Sr, Pb and Ca.
- M may be a combination of Sr and one or more metals selected from the group consisting of Ba, Pb and Ca.
- Part of Fe in the above general formula may be substituted with another metal element.
- the average particle size of the magnetic powder is preferably 13 nm or more and 22 nm or less, more preferably 13 nm or more and 19 nm or less, even more preferably 13 nm or more and 18 nm or less, and particularly preferably 14 nm or more and 17 nm. Below, it is most preferably 14 nm or more and 16 nm or less.
- the average particle size of the magnetic powder is 22 nm or less, even better electromagnetic conversion characteristics (for example, SNR) can be obtained in the high recording density magnetic tape 1 .
- the average particle size of the magnetic powder is 13 nm or more, the dispersibility of the magnetic powder is further improved, and even better electromagnetic conversion characteristics (for example, SNR) can be obtained.
- the average aspect ratio of the magnetic powder is preferably 1.0 or more and 3.0 or less, more preferably 1.5 or more and 2.8 or less, and even more preferably 1.8. 2.7 or less. If the average aspect ratio of the magnetic powder is within the range of 1.0 or more and 3.0 or less, the aggregation of the magnetic powder can be suppressed. In addition, when the magnetic powder is vertically oriented in the process of forming the magnetic layer 43, the resistance applied to the magnetic powder can be suppressed. Therefore, the perpendicular orientation of the magnetic powder can be improved.
- the average particle size and average aspect ratio of the magnetic powder are obtained as follows.
- the magnetic tape 1 to be measured is processed by the FIB method or the like to be thinned.
- a carbon layer and a tungsten layer are formed as protective films as a pretreatment for observing a cross-sectional TEM image, which will be described later.
- the carbon layer is formed on the magnetic layer 43 side surface and the back layer 44 side surface of the magnetic tape 1 by vapor deposition, and the tungsten layer is further formed on the magnetic layer 43 side surface by vapor deposition or sputtering. be.
- the thinning is performed along the length direction (longitudinal direction) of the magnetic tape 1 . That is, by the thinning, a cross section parallel to both the longitudinal direction and the thickness direction of the magnetic tape 1 is formed.
- the cross section of the obtained thin sample was examined with an acceleration voltage of 200 kV and a total magnification of 500,000 times. A cross-sectional observation is performed so that the entirety of 43 is included, and a TEM photograph is taken. The number of TEM photographs is prepared so that 50 particles can be extracted from which the plate diameter DB and plate thickness DA (see FIG. 24) shown below can be measured.
- the particle size of the hexagonal ferrite (hereinafter referred to as "particle size") is defined as the shape of the particles observed in the above TEM photograph, as shown in FIG. , the thickness or height is smaller than the major axis of the plate surface or bottom surface.), the major axis of the plate surface or bottom surface is taken as the value of the plate diameter DB. The thickness or height of the particles observed in the above TEM photograph is taken as the plate thickness DA value.
- the major axis means the longest diagonal distance.
- the thickness or height of the largest grain is defined as the plate thickness DA.
- 50 particles to be extracted from the TEM photograph taken are selected based on the following criteria. Particles partly protruding outside the field of view of the TEM photograph are not measured, but particles with clear contours and present in isolation are measured. When particles overlap, if the boundary between the two particles is clear and the overall shape of the particle can be determined, each particle is measured as a single particle, but the boundary is not clear and the overall shape of the particle cannot be determined Particles that do not have a shape are not measured as the shape of the particles cannot be determined.
- the plate thickness DA of each of the 50 selected particles is measured.
- the average plate thickness DA ave is obtained by simply averaging (arithmetic mean) the plate thicknesses DA thus obtained.
- the average thickness DA ave is the average grain thickness.
- the plate diameter DB of each magnetic powder is measured.
- 50 particles whose tabular diameter DB of the particles can be clearly confirmed are selected from the photographed TEM photographs.
- the plate diameter DB of each of the 50 selected particles is measured.
- a simple average (arithmetic mean) of the plate diameters DB obtained in this way is obtained to obtain an average plate diameter DB ave .
- the average platelet diameter DB ave is the average particle size.
- the average aspect ratio (DB ave /DA ave ) of the particles is obtained from the average plate thickness DA ave and the average plate diameter DB ave .
- the average particle volume of the magnetic powder is preferably 500 nm 3 or more and 2500 nm 3 or less, more preferably 500 nm 3 or more and 1600 nm 3 or less, still more preferably 500 nm 3 or more and 1500 nm 3 or less, especially It is preferably 600 nm 3 or more and 1200 nm 3 or less, and most preferably 600 nm 3 or more and 1000 nm 3 or less.
- the average particle volume of the magnetic powder is 2500 nm 3 or less, the same effects as when the average particle size of the magnetic powder is 22 nm or less can be obtained.
- the average particle volume of the magnetic powder is 500 nm 3 or more, the same effect as when the average particle size of the magnetic powder is 13 nm or more can be obtained.
- the average particle volume of magnetic powder is determined as follows. First, the average major axis length DA ave and the average tabular diameter DB ave are determined as described above for the method of calculating the average particle size of the magnetic powder. Next, the average volume V of the magnetic powder is obtained by the following formula.
- ⁇ iron oxide particles are hard magnetic particles capable of obtaining a high coercive force even when they are fine particles.
- the ⁇ -iron oxide particles have a spherical shape or have a cubic shape.
- the spherical shape shall include substantially spherical shape.
- the cubic shape includes a substantially cubic shape. Since the ⁇ -iron oxide particles have the above-described shape, when the ⁇ -iron oxide particles are used as the magnetic particles, compared to the case where the hexagonal barium ferrite particles are used as the magnetic particles, the magnetic tape 1 It is possible to reduce the contact area between the particles in the thickness direction and suppress the aggregation of the particles. Therefore, it is possible to improve the dispersibility of the magnetic powder and obtain even better electromagnetic conversion characteristics (for example, SNR).
- SNR electromagnetic conversion characteristics
- ⁇ -iron oxide particles have a core-shell structure. Specifically, the ⁇ -iron oxide particles are provided with a core portion and a two-layered shell portion provided around the core portion.
- the shell portion having a two-layer structure includes a first shell portion provided on the core portion and a second shell portion provided on the first shell portion.
- the core portion contains ⁇ -iron oxide.
- the ⁇ -iron oxide contained in the core portion preferably has an ⁇ -Fe 2 O 3 crystal as a main phase, more preferably a single-phase ⁇ -Fe 2 O 3 .
- the first shell part covers at least part of the periphery of the core part.
- the first shell portion may partially cover the periphery of the core portion, or may cover the entire periphery of the core portion. From the viewpoint of ensuring sufficient exchange coupling between the core portion and the first shell portion and improving the magnetic properties, it is preferable that the entire surface of the core portion is covered.
- the first shell part is a so-called soft magnetic layer, and includes a soft magnetic material such as ⁇ -Fe, Ni-Fe alloy or Fe-Si-Al alloy.
- ⁇ -Fe may be obtained by reducing ⁇ -iron oxide contained in the core.
- the second shell portion is an oxide film as an antioxidant layer.
- the second shell portion comprises alpha iron oxide, aluminum oxide or silicon oxide.
- ⁇ -iron oxide includes, for example, at least one iron oxide selected from Fe 3 O 4 , Fe 2 O 3 and FeO.
- the ⁇ -iron oxide may be obtained by oxidizing the ⁇ -Fe contained in the first shell.
- the ⁇ -iron oxide particles have the first shell portion as described above, the coercive force Hc of the core portion alone is maintained at a large value in order to ensure thermal stability, and the ⁇ -iron oxide particles (core-shell particles) as a whole can be adjusted to a coercive force Hc suitable for recording.
- the ⁇ -iron oxide particles have the second shell portion as described above, the ⁇ -iron oxide particles are exposed to the air during and before the manufacturing process of the magnetic tape 1, and the particle surface is rusted. can be suppressed from deteriorating the properties of the ⁇ -iron oxide particles. Therefore, deterioration of the characteristics of the magnetic tape 1 can be suppressed.
- the ⁇ -iron oxide particles may have a shell portion with a single-layer structure.
- the shell portion has the same configuration as the first shell portion.
- the ⁇ -iron oxide particles may contain an additive instead of the core-shell structure, or may have a core-shell structure and contain an additive. In this case, part of the Fe in the ⁇ -iron oxide particles is replaced with the additive.
- the coercive force Hc of the ⁇ -iron oxide particles as a whole can also be adjusted to a coercive force Hc suitable for recording, so that the easiness of recording can be improved.
- the additive is a metal element other than iron, preferably a trivalent metal element, more preferably at least one of Al, Ga and In, still more preferably at least one of Al and Ga.
- the ⁇ -iron oxide containing the additive is an ⁇ -Fe 2-x M x O 3 crystal (where M is a metal element other than iron, preferably a trivalent metal element, more preferably Al, Ga and In, even more preferably at least one of Al and Ga.
- M is a metal element other than iron, preferably a trivalent metal element, more preferably Al, Ga and In, even more preferably at least one of Al and Ga.
- x is, for example, 0 ⁇ x ⁇ 1.
- the average particle size of the magnetic powder is preferably 10 nm or more and 20 nm or less, more preferably 10 nm or more and 18 nm or less, even more preferably 10 nm or more and 16 nm or less, and particularly preferably 10 nm or more and 15 nm or less. , most preferably 10 nm or more and 14 nm or less.
- a region having a size of 1/2 of the recording wavelength is the actual magnetized region. Therefore, by setting the average particle size of the magnetic powder to half or less of the shortest recording wavelength, even better electromagnetic conversion characteristics (for example, SNR) can be obtained.
- the magnetic tape 1 having a high recording density (for example, the magnetic tape 1 configured to record a signal at the shortest recording wavelength of 40 nm or less) exhibits even better electromagnetic conversion.
- a characteristic eg, SNR
- the average particle size of the magnetic powder is 10 nm or more, the dispersibility of the magnetic powder is further improved, and even better electromagnetic conversion characteristics (for example, SNR) can be obtained.
- the average aspect ratio of the magnetic powder is preferably 1.0 or more and 3.0 or less, more preferably 1.0 or more and 2.5 or less, and even more preferably 1.0 or more. 2.1 or less, particularly preferably 1.0 or more and 1.8 or less. If the average aspect ratio of the magnetic powder is within the range of 1.0 or more and 3.0 or less, the aggregation of the magnetic powder can be suppressed. In addition, when the magnetic powder is vertically oriented in the process of forming the magnetic layer 43, the resistance applied to the magnetic powder can be suppressed. Therefore, the perpendicular orientation of the magnetic powder can be improved.
- the average particle size and average aspect ratio of the magnetic powder are obtained as follows.
- the magnetic tape 1 to be measured is processed by the FIB (Focused Ion Beam) method or the like to be thinned.
- FIB Flucused Ion Beam
- a carbon layer and a tungsten layer are formed as protective layers as a pretreatment for observing a cross-sectional TEM image, which will be described later.
- the carbon layer is formed on the magnetic layer 43 side surface and the back layer 44 side surface of the magnetic tape 1 by vapor deposition, and the tungsten layer is further formed on the magnetic layer 43 side surface by vapor deposition or sputtering. be.
- Thinning is performed along the length direction (longitudinal direction) of the magnetic tape 1 . That is, by the thinning, a cross section parallel to both the longitudinal direction and the thickness direction of the magnetic tape 1 is formed.
- the cross section of the obtained thin sample was examined with an acceleration voltage of 200 kV and a total magnification of 500,000 times. A cross-sectional observation is performed so that the entirety of 43 is included, and a TEM photograph is taken. Next, 50 particles whose shape can be clearly confirmed are selected from the TEM photograph taken, and the major axis length DL and the minor axis length DS of each particle are measured.
- the major axis length DL means the maximum distance (so-called maximum Feret diameter) between two parallel lines drawn from all angles so as to touch the outline of each particle.
- the minor axis length DS means the maximum particle length in the direction orthogonal to the major axis (DL) of the particle.
- the average major axis length DL ave is obtained by simply averaging (arithmetic mean) the major axis lengths DL of the measured 50 particles.
- the average major axis length DL ave obtained in this manner is taken as the average particle size of the magnetic powder.
- the short axis length DS of the measured 50 particles is simply averaged (arithmetic mean) to obtain the average short axis length DS ave .
- the average aspect ratio (DL ave /DS ave ) of the particles is obtained from the average long axis length DL ave and the average short axis length DS ave .
- the average particle volume of the magnetic powder is preferably 500 nm 3 or more and 4000 nm 3 or less, more preferably 500 nm 3 or more and 3000 nm 3 or less, even more preferably 500 nm 3 or more and 2000 nm 3 or less, especially It is preferably 600 nm 3 or more and 1600 nm 3 or less, and most preferably 600 nm 3 or more and 1300 nm 3 or less. Since the noise of the magnetic tape 1 is generally inversely proportional to the square root of the number of particles (i.e., proportional to the square root of the particle volume), a smaller particle volume can provide better electromagnetic conversion characteristics (for example, SNR). can.
- the average particle volume of the magnetic powder is 4000 nm 3 or less, it is possible to obtain even better electromagnetic conversion characteristics (for example, SNR) as in the case where the average particle size of the magnetic powder is 20 nm or less.
- the average particle volume of the magnetic powder is 500 nm 3 or more, the same effect as when the average particle size of the magnetic powder is 10 nm or more can be obtained.
- the average volume of the magnetic powder is obtained as follows.
- the magnetic tape 1 is processed by FIB (Focused Ion Beam) method or the like to be thinned.
- FIB Flucused Ion Beam
- a carbon film and a tungsten thin film are formed as protective films as a pretreatment for observing a cross-sectional TEM image, which will be described later.
- the carbon film is formed on the magnetic layer 43 side surface and the back layer 44 side surface of the magnetic tape 1 by vapor deposition, and the tungsten thin film is further formed on the magnetic layer 43 side surface by vapor deposition or sputtering.
- the thinning is performed along the length direction (longitudinal direction) of the magnetic tape 1 . That is, by the thinning, a cross section parallel to both the longitudinal direction and the thickness direction of the magnetic tape 1 is formed.
- the thin sample thus obtained was examined at an acceleration voltage of 200 kV and a total magnification of 500,000 times. A cross-sectional observation is performed so that it can be seen, and a TEM photograph is obtained. Note that the magnification and the acceleration voltage may be appropriately adjusted according to the type of apparatus.
- 50 particles with a clear particle shape are selected from the TEM photograph taken, and the side length DC of each particle is measured.
- the average side length DC ave is obtained by simply averaging (arithmetic mean) the side lengths DC of the 50 particles measured.
- the cobalt ferrite particles preferably have uniaxial crystal anisotropy. Since the cobalt ferrite particles have uniaxial crystal anisotropy, the magnetic powder can be preferentially crystalline in the thickness direction (perpendicular direction) of the magnetic tape 1 .
- Cobalt ferrite particles have, for example, a cubic shape. In this specification, the cubic shape includes a substantially cubic shape.
- the Co-containing spinel ferrite may further contain at least one of Ni, Mn, Al, Cu and Zn in addition to Co.
- a Co-containing spinel ferrite has, for example, an average composition represented by the following formula.
- CoxMyFe2Oz _ _ _ _ (Wherein, M is, for example, at least one of Ni, Mn, Al, Cu and Zn.
- x is a value within the range of 0.4 ⁇ x ⁇ 1.0
- y is a value within the range of 0 ⁇ y ⁇ 0.3, provided that x and y satisfy the relationship of (x+y) ⁇ 1.0
- z is a value within the range of 3 ⁇ z ⁇ 4.
- a part of Fe may be substituted with another metal element.
- the average particle size of the magnetic powder is preferably 8 nm or more and 16 nm or less, more preferably 8 nm or more and 13 nm or less, and even more preferably 8 nm or more and 10 nm or less.
- the average particle size of the magnetic powder is 16 nm or less, even better electromagnetic conversion characteristics (for example, SNR) can be obtained in the high recording density magnetic tape 1 .
- the average particle size of the magnetic powder is 8 nm or more, the dispersibility of the magnetic powder is further improved, and even better electromagnetic conversion characteristics (for example, SNR) can be obtained.
- the method for calculating the average particle size of the magnetic powder is the same as the method for calculating the average particle size of the magnetic powder when the magnetic powder contains ⁇ -iron oxide particles.
- the average aspect ratio of the magnetic powder is preferably 1.0 or more and 3.0 or less, more preferably 1.0 or more and 2.5 or less, and even more preferably 1.0 or more. 2.1 or less, particularly preferably 1.0 or more and 1.8 or less. If the average aspect ratio of the magnetic powder is within the range of 1.0 or more and 3.0 or less, the aggregation of the magnetic powder can be suppressed. In addition, when the magnetic powder is vertically oriented in the process of forming the magnetic layer 43, the resistance applied to the magnetic powder can be suppressed. Therefore, the perpendicular orientation of the magnetic powder can be improved.
- the method for calculating the average aspect ratio of the magnetic powder is the same as the method for calculating the average aspect ratio of the magnetic powder when the magnetic powder contains ⁇ -iron oxide particles.
- the average particle volume of the magnetic powder is preferably 500 nm 3 or more and 4000 nm 3 or less, more preferably 600 nm 3 or more and 2000 nm 3 or less, and even more preferably 600 nm 3 or more and 1000 nm 3 or less.
- the average particle volume of the magnetic powder is 4000 nm 3 or less, the same effect as when the average particle size of the magnetic powder is 16 nm or less can be obtained.
- the average particle volume of the magnetic powder is 500 nm 3 or more, the same effect as when the average particle size of the magnetic powder is 8 nm or more can be obtained.
- the method for calculating the average particle volume of the magnetic component is the same as the method for calculating the average particle volume when the ⁇ -iron oxide particles have a cubic shape.
- binders include thermoplastic resins, thermosetting resins, and reactive resins.
- thermoplastic resins include vinyl chloride, vinyl acetate, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylate-acrylonitrile copolymer, acrylic Acid ester-vinyl chloride-vinylidene chloride copolymer, acrylic acid ester-acrylonitrile copolymer, acrylic acid ester-vinylidene chloride copolymer, methacrylic acid ester-vinylidene chloride copolymer, methacrylic acid ester-vinylidene chloride copolymer , methacrylate ester-ethylene copolymer, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, acrylonitrile-butadiene copolymer, polyamide resin, polyvinyl but
- thermosetting resins examples include phenol resins, epoxy resins, polyurethane curing resins, urea resins, melamine resins, alkyd resins, silicone resins, polyamine resins, and urea-formaldehyde resins.
- R1, R2, and R3 represent a hydrogen atom or a hydrocarbon group
- X- represents a halogen element ion such as fluorine, chlorine, bromine, or iodine, an inorganic ion, or an organic ion.
- -OH, - Polar functional groups such as SH, —CN, and epoxy groups may be introduced.
- the amount of these polar functional groups introduced into the binder is preferably 10 -1 to 10 -8 mol/g, more preferably 10 -2 to 10 -6 mol/g.
- the lubricant contains, for example, at least one selected from fatty acids and fatty acid esters, preferably both fatty acids and fatty acid esters. Containing a lubricant in the magnetic layer 43 , particularly containing both a fatty acid and a fatty acid ester, contributes to improving the running stability of the magnetic tape 1 . More particularly, good running stability is achieved by the magnetic layer 43 containing a lubricant and having pores. The improvement in running stability is considered to be due to the fact that the dynamic friction coefficient of the magnetic layer 43 side surface of the magnetic tape 1 is adjusted to a value suitable for the running of the magnetic tape 1 by the lubricant.
- the fatty acid may preferably be a compound represented by the following general formula (1) or (2).
- the fatty acid may contain one or both of a compound represented by the following general formula (1) and a compound represented by general formula (2).
- the fatty acid ester may preferably be a compound represented by the following general formula (3) or (4).
- a compound represented by the following general formula (3) and a compound represented by general formula (4) may be included as the fatty acid ester.
- the lubricant is one or both of the compound represented by the general formula (1) and the compound represented by the general formula (2), and the compound represented by the general formula (3) and the compound represented by the general formula (4). By including either one or both of, it is possible to suppress an increase in the dynamic friction coefficient due to repeated recording or reproduction of the magnetic tape 1 .
- CH3 ( CH2 ) kCOOH (1) (However, in the general formula (1), k is an integer selected from the range of 14 or more and 22 or less, more preferably 14 or more and 18 or less.)
- Antistatic agents include, for example, carbon black, natural surfactants, nonionic surfactants, cationic surfactants and the like.
- Abrasives include, for example, ⁇ -alumina, ⁇ -alumina, ⁇ -alumina, silicon carbide, chromium oxide, cerium oxide, ⁇ -iron oxide, corundum, silicon nitride, titanium carbide, and oxides with an ⁇ conversion rate of 90% or more. Titanium, silicon dioxide, tin oxide, magnesium oxide, tungsten oxide, zirconium oxide, boron nitride, zinc oxide, calcium carbonate, calcium sulfate, barium sulfate, molybdenum disulfide, and magnetic iron oxide. iron oxides, and those surface-treated with aluminum and/or silica, if necessary, and the like.
- curing agents examples include polyisocyanate and the like.
- polyisocyanates include aromatic polyisocyanates such as adducts of tolylene diisocyanate (TDI) and active hydrogen compounds, and aliphatic polyisocyanates such as adducts of hexamethylene diisocyanate (HMDI) and active hydrogen compounds. mentioned.
- the weight average molecular weight of these polyisocyanates is desirably in the range of 100-3000.
- anti-rust examples include phenols, naphthols, quinones, nitrogen atom-containing heterocyclic compounds, oxygen atom-containing heterocyclic compounds, and sulfur atom-containing heterocyclic compounds.
- Non-magnetic reinforcing particles examples include aluminum oxide ( ⁇ , ⁇ or ⁇ alumina), chromium oxide, silicon oxide, diamond, garnet, emery, boron nitride, titanium carbide, silicon carbide, titanium carbide, titanium oxide (rutile or anatase type titanium oxide) and the like.
- the underlayer 42 is for reducing unevenness on the surface of the base material 41 and adjusting unevenness on the surface of the magnetic layer 43 .
- the underlayer 42 is a non-magnetic layer containing non-magnetic powder, a binder and a lubricant.
- the underlayer 42 supplies lubricant to the surface of the magnetic layer 43 .
- the base layer 42 may further contain at least one additive selected from among an antistatic agent, a curing agent, an antirust agent, and the like, if necessary.
- the average thickness t2 of the underlayer 42 is preferably 0.3 ⁇ m or more and 1.2 ⁇ m or less, more preferably 0.3 ⁇ m or more and 0.9 ⁇ m or less, and 0.3 ⁇ m or more and 0.6 ⁇ m or less.
- the average thickness t 2 of the underlayer 42 is obtained in the same manner as the average thickness t 1 of the magnetic layer 43 .
- the magnification of the TEM image is appropriately adjusted according to the thickness of the underlying layer 42 .
- the average thickness t2 of the underlayer 42 is 1.2 ⁇ m or less, the stretchability of the magnetic tape 1 due to an external force is further increased, so that it is easier to adjust the width of the magnetic tape 1 by adjusting the tension.
- the non-magnetic powder includes, for example, at least one of inorganic powder and organic powder. Also, the non-magnetic powder may contain carbon powder such as carbon black. One type of non-magnetic powder may be used alone, or two or more types of non-magnetic powder may be used in combination.
- Inorganic particles include, for example, metals, metal oxides, metal carbonates, metal sulfates, metal nitrides, metal carbides, metal sulfides, and the like. Examples of the shape of the non-magnetic powder include various shapes such as acicular, spherical, cubic, and plate-like, but are not limited to these shapes.
- binder (binder, lubricant)
- lubricant The binder and lubricant are the same as those for the magnetic layer 43 described above.
- the antistatic agent, curing agent, and antirust agent are the same as those of the magnetic layer 43 described above.
- the back layer 44 contains a binder and non-magnetic powder.
- the back layer 44 may further contain at least one additive such as a lubricant, a curing agent and an antistatic agent, if necessary.
- the binder and non-magnetic powder are the same as those for the underlayer 42 described above.
- the average particle size of the non-magnetic powder is preferably 10 nm or more and 150 nm or less, more preferably 15 nm or more and 110 nm or less.
- the average particle size of the non-magnetic powder is determined in the same manner as the average particle size of the magnetic powder.
- the non-magnetic powder may contain non-magnetic powder having two or more particle size distributions.
- the upper limit of the average thickness of the back layer 44 is preferably 0.6 ⁇ m or less. If the upper limit of the average thickness of the back layer 44 is 0.6 ⁇ m or less, the thickness of the underlayer 42 and the substrate 41 can be kept thick even when the average thickness of the magnetic tape 1 is 5.6 ⁇ m or less. , the running stability of the magnetic tape 1 in the recording/reproducing apparatus can be maintained. Although the lower limit of the average thickness of the back layer 44 is not particularly limited, it is, for example, 0.2 ⁇ m or more.
- the back layer 44 has a surface provided with a large number of protrusions.
- a large number of protrusions are for forming a large number of holes in the surface of the magnetic layer 43 when the magnetic tape 1 is wound into a roll.
- a large number of holes are composed of, for example, a large number of non-magnetic particles protruding from the surface of the back layer 44 .
- the upper limit of the average thickness (average total thickness) t T of the magnetic tape 1 is 5.6 ⁇ m or less, preferably 5.0 ⁇ m or less, more preferably 4.6 ⁇ m or less, and even more preferably 4.4 ⁇ m or less.
- the recording capacity that can be recorded in one data cartridge can be increased as compared with general magnetic tapes.
- the lower limit of the average thickness t T of the magnetic tape 1 is not particularly limited, it is, for example, 3.5 ⁇ m or more.
- the average thickness t T of the magnetic tape 1 is obtained as follows. First, a magnetic tape 1 having a width of 1/2 inch is prepared and cut into a length of 250 mm to prepare a sample. Next, using a Mitutoyo laser hologram (LGH-110C) as a measuring device, the thickness of the sample is measured at 5 or more points, and the measured values are simply averaged (arithmetic average) to obtain an average Calculate the value t T [ ⁇ m]. It is assumed that the measurement position is randomly selected from the sample.
- LGH-110C Mitutoyo laser hologram
- the upper limit of the coercive force Hc2 of the magnetic layer 43 in the longitudinal direction of the magnetic tape 1 is preferably 2000 Oe or less, more preferably 1900 Oe or less, and even more preferably 1800 Oe or less. If the coercive force Hc2 of the magnetic layer 43 in the longitudinal direction is 2000 Oe or less, sufficient electromagnetic conversion characteristics can be obtained even with a high recording density.
- the lower limit of the coercive force Hc2 of the magnetic layer 43 measured in the longitudinal direction of the magnetic tape 1 is preferably 1000 Oe or more.
- the coercive force Hc2 of the magnetic layer 43 measured in the longitudinal direction is 1000 Oe or more, demagnetization due to leakage flux from the recording head can be suppressed.
- the above coercive force Hc2 is obtained as follows. First, unwind the magnetic tape 1 contained in the cartridge, cut the magnetic tape 1 at a position of 30 m from one end of the outermost periphery, and cut the magnetic tape 1 into three pieces with double-sided tape so that the longitudinal direction of the magnetic tape 1 is the same. After being superimposed, a measurement sample is produced by punching with a punch of ⁇ 6.39 mm. At this time, marking is performed with any non-magnetic ink so that the longitudinal direction (running direction) of the magnetic tape 1 can be recognized. Then, the MH loop of the measurement sample (entire magnetic tape 1) corresponding to the longitudinal direction (running direction) of the magnetic tape 1 is measured using a vibrating sample magnetometer (VSM).
- VSM vibrating sample magnetometer
- the coating films (underlying layer 42, magnetic layer 43, backing layer 44, etc.) of the magnetic tape 1 cut out above are wiped off with acetone, ethanol, or the like, leaving only the base material 41.
- three sheets of the obtained base material 41 are superimposed with double-sided tape, and then punched out with a punch of ⁇ 6.39 mm to prepare a sample for background correction (hereinafter simply referred to as "correction sample").
- the VSM is used to measure the MH loop of the correction sample (substrate 41) corresponding to the vertical direction of the substrate 41 (perpendicular direction of the magnetic tape 1).
- a high-sensitivity vibrating sample magnetometer manufactured by Toei Kogyo Co., Ltd. -15 type” is used. Measurement conditions are measurement mode: full loop, maximum magnetic field: 15 kOe, magnetic field step: 40 bits, Time constant of locking amp: 0.3 sec, Waiting time: 1 sec, MH average number: 20.
- the MH loop of the measurement sample is corrected.
- the MH loop after background correction is obtained.
- the measurement/analysis program attached to the "VSM-P7-15 type" is used for the calculation of this background correction.
- the coercive force Hc2 is obtained from the obtained MH loop after background correction.
- the measurement/analysis program attached to the "VSM-P7-15 model” is used. It should be noted that the above MH loop measurements are all performed at 25° C. ⁇ 2° C. and 50% RH ⁇ 5% RH. Also, when measuring the MH loop in the longitudinal direction of the magnetic tape 1, "demagnetizing field correction" is not performed.
- the squareness ratio S1 of the magnetic layer 43 in the perpendicular direction (thickness direction) of the magnetic tape 1 is preferably 65% or more, more preferably 70% or more, still more preferably 75% or more, particularly preferably 80% or more, and most preferably. is 85% or more.
- the squareness ratio S1 is 65% or more, the perpendicular orientation of the magnetic powder is sufficiently high, so that even better electromagnetic conversion characteristics (for example, SNR) can be obtained.
- the squareness ratio S1 in the vertical direction is obtained as follows. First, unwind the magnetic tape 1 contained in the cartridge, cut the magnetic tape 1 at a position of 30 m from one end of the outermost periphery, and cut the magnetic tape 1 into three pieces with double-sided tape so that the longitudinal direction of the magnetic tape 1 is the same. After being superimposed, a measurement sample is produced by punching with a punch of ⁇ 6.39 mm. At this time, marking is performed with any non-magnetic ink so that the longitudinal direction (running direction) of the magnetic tape 1 can be recognized. Then, the MH loop of the measurement sample (entire magnetic tape 1) corresponding to the longitudinal direction (running direction) of the magnetic tape 1 is measured using a vibrating sample magnetometer (VSM).
- VSM vibrating sample magnetometer
- the coating films (underlying layer 42, magnetic layer 43, backing layer 44, etc.) of the magnetic tape 1 cut out above are wiped off with acetone, ethanol, or the like, leaving only the base material 41.
- three sheets of the obtained base material 41 are superimposed with double-sided tape, and then punched out with a punch of ⁇ 6.39 mm to prepare a sample for background correction (hereinafter simply referred to as "correction sample").
- the VSM is used to measure the MH loop of the correction sample (substrate 41) corresponding to the vertical direction of the substrate 41 (perpendicular direction of the magnetic tape 1).
- a high-sensitivity vibrating sample magnetometer manufactured by Toei Kogyo Co., Ltd. -15 type” is used. Measurement conditions are measurement mode: full loop, maximum magnetic field: 15 kOe, magnetic field step: 40 bits, Time constant of locking amp: 0.3 sec, Waiting time: 1 sec, MH average number: 20.
- the MH loop of the measurement sample (entire magnetic tape 1) and the MH loop of the correction sample (substrate 41)
- the MH loop of the measurement sample (entire magnetic tape 1) is corrected.
- the MH loop after background correction is obtained.
- the measurement/analysis program attached to the "VSM-P7-15 type" is used for the calculation of this background correction.
- the squareness ratio S2 of the magnetic layer 43 in the longitudinal direction (running direction) of the magnetic tape 1 is preferably 35% or less, more preferably 30% or less, even more preferably 25% or less, particularly preferably 20% or less, most preferably 20% or less. is 15% or less.
- the squareness ratio S2 is 35% or less, the perpendicular orientation of the magnetic powder is sufficiently high, so that even better electromagnetic conversion characteristics (for example, SNR) can be obtained.
- the squareness ratio S2 in the longitudinal direction is obtained in the same manner as the squareness ratio S1, except that the MH loop is measured in the longitudinal direction (running direction) of the magnetic tape 1 and the base material 41.
- the surface roughness of the back surface (the surface roughness of the back layer 44) R b is preferably R b ⁇ 6.0 [nm].
- R b of the back surface is within the above range, even better electromagnetic conversion characteristics can be obtained.
- the azimuth angle inclination (azimuth angle) of the servo frames SF forming the servo pattern 6 is set to 12°. ° or less. Further, although the azimuth angle tilts are of two types, "/" and " ⁇ ", the servo pattern may further include azimuth angle tilts having different tilt angles.
- the magnetic tape conforming to the LTO standard has been taken as an example of the tape-shaped magnetic recording medium, but it is also applicable to magnetic tapes of other standards.
- a method of recording servo patterns in a plurality of servo bands arranged at intervals in the width direction of a magnetic layer of a magnetic tape comprising: running the magnetic tape at a predetermined tension; The plurality of A servo pattern recording method for recording a servo pattern in a servo band.
- the servo pattern recording method according to (1) above The servo pattern recording method, wherein a difference between the second pitch and the first pitch is 5 ⁇ m or less.
- a device for recording servo patterns in a plurality of servo bands arranged at intervals in the width direction of a magnetic layer of a magnetic tape comprising a servo write head having a plurality of recording units arranged corresponding to the plurality of servo bands;
- the plurality of recording sections comprise a second pitch narrower than a first pitch, which is an arrangement interval between two servo read heads in a tape drive device that records data on the magnetic layer or reproduces data recorded on the magnetic layer.
- a servo pattern recording apparatus having magnetic gaps for recording servo patterns in the plurality of servo bands with a pitch of .
- (6) The servo pattern recording apparatus according to (5) above, The servo pattern recording apparatus, wherein a difference between the second pitch and the first pitch is 5 ⁇ m or less.
- (7) The servo pattern recording apparatus according to (6) above, The servo pattern recording device, wherein the second pitch is 2854.2 ⁇ m or more and 2858.7 ⁇ m or less.
- (11) comprising a magnetic layer having a plurality of servo bands arranged at intervals in the width direction;
- the magnetic layer has two servo read heads in a tape drive device in which a servo band pitch, which is the distance between two adjacent servo bands, records information on the magnetic layer or reproduces information recorded on the magnetic layer.
- a magnetic tape having, at least in part, an area narrower than the arrangement interval of the magnetic tape.
- the magnetic tape has a magnetic layer on which a plurality of servo patterns are recorded at intervals in the tape width direction,
- the magnetic layer is A servo band pitch, which is the distance between two adjacent servo bands, is longer than the spacing between two servo read heads in a tape drive device that records information on the magnetic layer or reproduces information recorded on the magnetic layer.
- the tape cartridge according to (14) above The first region is a region on the first end side of the outer periphery of the magnetic tape wound on the tape reel, The second area is an area of a second end on an inner peripheral side of the magnetic tape wound around the tape reel.
- a servo band pitch of the magnetic layer gradually widens from the first end side toward the second end side of the magnetic tape.
Landscapes
- Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
Abstract
Description
前記磁気テープを所定のテンションで走行させ、
前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する。
前記複数の記録部は、前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する磁気ギャップをそれぞれ有する。
前記磁気テープを所定のテンションで走行させ、
前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する。
前記磁性層は、隣接する2つのサーボバンド間の距離であるサーボバンドピッチが、前記磁性層に情報を記録し又は前記磁性層に記録された情報を再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔よりも狭い領域を、少なくとも一部に有する。
前記磁気テープは、テープ幅方向に間隔をおいて記録された複数のサーボパターンが記録された磁性層を有する。
前記磁性層は、隣接する2つのサーボバンド間の距離であるサーボバンドピッチが、前記磁性層に情報を記録し又は前記磁性層に記録された情報を再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔よりも狭い第1の領域と、前記サーボバンドピッチが前記2つのサーボリードヘッドの配置間隔よりも広い第2の領域と、を有する。
[テープカートリッジ]
図1は本技術の一実施形態に係るテープカートリッジ10を示す分解斜視図である。本実施形態の説明では、テープカートリッジ10として、LTO規格に準拠するテープカートリッジを例に挙げて説明する。
なお、磁気テープ1を構成する各層の詳細については後述する。
もしくは、ドライブヘッドを利用した測定方法として、テープ走行時の変動を無視するため、ドライブヘッドをRead While Write(記録時再生)状態とし、ドライブヘッドのAzimuthを変化させた場合の出力変化から記録トラック幅Wdを測定することができる。(IEEE_Sept1996_Crosstrack Profiles of Thin Film MR Tape Heads Using the Azimuth Displacement Method)
図6は、テープドライブ装置30を示す図である。テープドライブ装置30は、磁気テープ1にデータを記録し、又は、磁気テープ1に記録されたデータを再生することが可能なデータ記録/再生装置である。
続いて、磁気テープ1のサーボバンドsにサーボパターン6を記録するサーボパターン記録装置の構成について説明する。図9は、本技術の一実施形態に係るサーボパターン記録装置100を示す正面図である。図10は、サーボパターン記録装置100の一部を示す部分拡大図である
なお、上記第2の方向の調整方法としては、例えば、永久磁石112aの回転角度を任意とし、磁性層43全体を消磁後に、磁性層43にサーボパターン6を記録し、その再生波形の傾きに基づいて、磁気テープ1の幅方向を中心とする永久磁石112aの回転角度を調整するようにしてもよい。
続いて、サーボパターン6の詳細について説明する。サーボパターン6は、「ECMA-319規格」に準拠したデータ構造を有する。図11(A)は、サーボパターン6に埋め込まれるLPOSワードのデータ構造を示す図であり、図11(B)は製造業者ワードを説明する図である。
製造業者ワードTW:D,A0,A1,A0,A1,・・・,A0,A1
各サーボバンドs(s0~s4)には、各データバンドについて異なる組み合わせのサーボバンド識別情報が書き込まれる。例えば、データバンドd0に隣接する2つのサーボバンドs2,s3から得られるサーボバンド識別情報の組み合わせは、データバンドd1に隣接するサーボバンドs1,s2から得られるサーボバンド識別情報の組み合わせと、データバンドd2に隣接するサーボバンドs3,s4から得られるサーボバンド識別情報の組み合わせと、データバンドd3に隣接する2つのサーボバンドs0,s1から得られるサーボバンド識別情報の組み合わせと、それぞれ異なる。このように、一のデータバンドに隣接する2つのサーボバンドから得られるサーボバンド識別情報を、他のデータバンドに隣接する2つのサーボバンドから得られるサーボバンド識別情報と異ならせることにより、個々のデータバンドの特定が可能となる。
[テープ幅の変動について]
ところで、磁気テープ1は、一般に、ベースフィルム(基材41)への磁性材料の塗布、カレンダー処理、裁断処理、サーボパターン6の記録処理などを経て製造される。これらの処理は、ベースフィルムを一定のテンションで巻き取りながら行われるため、完成した磁気テープ1は内部歪を有し、時間の経過に伴って磁気テープ1の幅は広がる傾向にある。また、磁気テープ1の保管環境が高温度あるいは高湿度になるほど、テープ幅は広がりやすい。さらに、テープカートリッジ10のテープリール13に巻装された磁気テープ1においては、テープリール13の内周側の方が外周側よりも高い巻き圧が加わるため、外周側に比べてテープ幅は広がる傾向にある。特に、高容量が求められる近年の磁気テープにおいては、ベースフィルムの厚みや塗布厚の薄膜化によりテープ全厚が薄く、磁気テープのリールへの巻回数が増加しているため、磁気テープの幅寸法の変動による影響が益々大きくなる。
ここで、磁気テープ1のサーボバンドピッチが第1のピッチP1と同一である場合、一方のサーボリードヘッド132のサーボトレースラインTが一方のサーボバンド上のサーボパターン6の中心に位置していれば、他方のサーボリードヘッド132のサーボトレースラインTも他方のサーボバンド上のサーボパターン6の中心に位置する。一方、他方のサーボトレースラインTが他方のサーボパターン6の中心位置から外れている場合、磁気テープ1のサーボバンドピッチは、第1のピッチP1とは異なる値になる。
ここでは図19の縦軸に示すように、各サーボトレースラインTの測定値の差分をとり、その差が正の場合ならばサーボバンドピッチは狭まり、負の場合ならばサーボバンドピッチが広がったものとする。
なお、テープ走行時のテンションは、サーボパターン記録時及びサーボパターン再生時のいずれにおいても、0.55Nとした。また、図中TA1は、製作直後のテープカートリッジの磁気テープに関する測定値であり、TB1は、恒温槽内で29±2℃、80±5%RHの条件で一週間保管したテープカートリッジの磁気テープに関する測定値である。
続いて、サーボバンドピッチの測定方法について説明する。
磁気テープ1を、フェリコロイド現像液として、例えば、シグマハイケミカル社製現像液「シグマーカーQ」等の磁性コロイド溶液を用いて現像し、隣接する2つのサーボバンドに記録されたサーボパターン6の現像パターンの中心位置の間隔を測定することで、サーボバンドピッチを算出する。
テープドライブ装置30を用いてサーボバンドピッチを測定することができる。ここでは図22に示すように、サーボバンドs2とサーボバンドs3との間に挟まれたデータバンドd0をドライブヘッド36がトラッキングする例について説明する。
さらに、[数1]式における距離AC,ABおよび[数2]式における距離CA,CDとして、サーボ再生波形における振幅の負の最大値を示す位置(下ピーク位置)間の距離が採用されてもよい。
あるいは、[数1]式における距離AC,ABおよび[数2]式における距離CA,CDとして、サーボ再生波形における振幅の正の最大値を示す位置(上ピーク位置)間の距離と負の最大値を示す位置(下ピーク位置)間の距離との平均値が採用されてもよい。
サーボバンドs2においては、
(38.5/76)×(76/2tan12°)=90.5641[μm]
サーボバンドs3においては、
(37.5/76)×(76/2tan12°)=88.2118[μm]
となる。これらの値の差分は、
88.2118-90.5641=-2.3523[μm]
となる。
したがって、この場合におけるサーボバンドピッチは、サーボリードヘッド間の間隔である第1のピッチP1より、2.3523μmだけ広い値として求められる。
続いて、磁気テープ1の詳細について説明する。
図2に示すように、基材41は、下地層42および磁性層43を支持する非磁性支持体である。基材41は、長尺のフィルム状を有する。基材41の平均厚みの上限値は、好ましくは4.2μm以下、より好ましくは4.0μm以下、さらに好ましくは3.8μm以下、最も好ましくは3.4μm以下である。基材41の平均厚みの上限値が4.2μm以下であると、1データカートリッジ内に記録できる記録容量を一般的な磁気テープよりも高めることができる。基材41の平均厚みの下限値は、好ましくは3μm以上、より好ましくは3.2μm以上である。基材41の平均厚みの下限値が3μm以上であると、基材41の強度低下を抑制することができる。
磁性層43は、信号を磁化パターンにより記録するための記録層である。磁性層43は、垂直記録型の記録層であってもよいし、長手記録型の記録層であってもよい。磁性層43は、例えば、磁性粉、結着剤および潤滑剤を含む。磁性層43が、必要に応じて、帯電防止剤、研磨剤、硬化剤、防錆剤および非磁性補強粒子等のうちの少なくとも1種の添加剤をさらに含んでいてもよい。磁性層43は、磁性材料の塗布膜で構成される場合に限られず、磁性材料のスパッタ膜や蒸着膜で構成されてもよい。
(注1)Nano World社製SPMプローブNCH ノーマルタイプPointProbe L
(カンチレバー長)=125μm
装置:TEM(日立製作所製H9000NAR)
加速電圧:300kV
倍率:100、000倍
磁性粉は、複数の磁性粒子を含む。磁性粒子は、例えば、六方晶フェライトを含む粒子(以下「六方晶フェライト粒子」という。)、イプシロン型酸化鉄(ε酸化鉄)を含む粒子(以下「ε酸化鉄粒子」という。)またはCo含有スピネルフェライトを含む粒子(以下「コバルトフェライト粒子」という。)である。磁性粉は、磁気テープ1の厚み方向(垂直方向)に優先的に結晶配向していることが好ましい。
六方晶フェライト粒子は、例えば、六角板状等の板状または六角柱状等の柱状(但し、厚さまたは高さが板面または底面の長径より小さい。)を有する。本明細書において、六角坂状は、ほぼ六角坂状を含むものとする。六方晶フェライトは、好ましくはBa、Sr、PbおよびCaのうちの少なくとも1種、より好ましくはBaおよびSrのうちの少なくとも1種を含む。六方晶フェライトは、具体的には例えばバリウムフェライトまたはストロンチウムフェライトであってもよい。バリウムフェライトは、Ba以外にSr、PbおよびCaのうちの少なくとも1種をさらに含んでいてもよい。ストロンチウムフェライトは、Sr以外にBa、PbおよびCaのうちの少なくとも1種をさらに含んでいてもよい。
ε酸化鉄粒子は、微粒子でも高保磁力を得ることができる硬磁性粒子である。ε酸化鉄粒子は、球状を有しているか、または立方体状を有している。本明細書において、球状は、ほぼ球状を含むものとする。また、立方体状には、ほぼ立方体状を含むものとする。ε酸化鉄粒子が上記のような形状を有しているため、磁性粒子としてε酸化鉄粒子を用いた場合、磁性粒子として六角板状のバリウムフェライト粒子を用いた場合に比べて、磁気テープ1の厚み方向における粒子同士の接触面積を低減し、粒子同士の凝集を抑制することができる。したがって、磁性粉の分散性を高め、さらに優れた電磁変換特性(例えばSNR)を得ることができる。
V=(π/6)×DLave 3
Vave=DCave 3
コバルトフェライト粒子は、一軸結晶異方性を有することが好ましい。コバルトフェライト粒子が一軸結晶異方性を有することで、磁性粉を磁気テープ1の厚み方向(垂直方向)に優先的に結晶配向させることができる。コバルトフェライト粒子は、例えば、立方体状を有している。本明細書において、立方体状は、ほぼ立方体状を含むものとする。Co含有スピネルフェライトが、Co以外にNi、Mn、Al、CuおよびZnのうちの少なくとも1種をさらに含んでいてもよい。
CoxMyFe2OZ
(但し、式中、Mは、例えば、Ni、Mn、Al、CuおよびZnのうちの少なくとも1種の金属である。xは、0.4≦x≦1.0の範囲内の値である。yは、0≦y≦0.3の範囲内の値である。但し、x、yは(x+y)≦1.0の関係を満たす。zは3≦z≦4の範囲内の値である。Feの一部が他の金属元素で置換されていてもよい。)
結着剤としては、例えば、熱可塑性樹脂、熱硬化性樹脂、反応型樹脂等が挙げられる。熱可塑性樹脂としては、例えば、塩化ビニル、酢酸ビニル、塩化ビニル-酢酸ビニル共重合体、塩化ビニル-塩化ビニリデン共重合体、塩化ビニル-アクリロニトリル共重合体、アクリル酸エステル-アクリロニトリル共重合体、アクリル酸エステル-塩化ビニル-塩化ビニリデン共重合体、アクリル酸エステル-アクリロニトリル共重合体、アクリル酸エステル-塩化ビニリデン共重合体、メタクリル酸エステル-塩化ビニリデン共重合体、メタクリル酸エステル-塩化ビニル共重合体、メタクリル酸エステル-エチレン共重合体、ポリフッ化ビニル、塩化ビニリデン-アクリロニトリル共重合体、アクリロニトリル-ブタジエン共重合体、ポリアミド樹脂、ポリビニルブチラール、セルロース誘導体(セルロースアセテートブチレート、セルロースダイアセテート、セルローストリアセテート、セルロースプロピオネート、ニトロセルロース)、スチレンブタジエン共重合体、ポリウレタン樹脂、ポリエステル樹脂、アミノ樹脂、合成ゴム等が挙げられる。
潤滑剤は、例えば脂肪酸および脂肪酸エステルから選ばれる少なくとも1種、好ましくは脂肪酸および脂肪酸エステルの両方を含む。磁性層43が潤滑剤を含むことが、特には磁性層43が脂肪酸および脂肪酸エステルの両方を含むことが、磁気テープ1の走行安定性の向上に貢献する。より特には、磁性層43が潤滑剤を含み且つ細孔を有することによって、良好な走行安定性が達成される。当該走行安定性の向上は、磁気テープ1の磁性層43側表面の動摩擦係数が上記潤滑剤により、磁気テープ1の走行に適した値へ調整されるためと考えられる。
(但し、一般式(1)において、kは14以上22以下の範囲、より好ましくは14以上18以下の範囲から選ばれる整数である。)
(但し、一般式(2)において、nとmとの和は12以上20以下の範囲、より好ましくは14以上18以下の範囲から選ばれる整数である。)
(但し、一般式(3)において、pは14以上22以下、より好ましくは14以上18以下の範囲から選ばれる整数であり、且つ、qは2以上5以下の範囲、より好ましくは2以上4以下の範囲から選ばれる整数である。)
(但し、一般式(4)において、rは14以上22以下の範囲から選ばれる整数であり、sは1以上3以下の範囲から選ばれる整数である。)
帯電防止剤としては、例えば、カーボンブラック、天然界面活性剤、ノニオン性界面活性剤、カチオン性界面活性剤等が挙げられる。
研磨剤としては、例えば、α化率90%以上のα-アルミナ、β-アルミナ、γ-アルミナ、炭化ケイ素、酸化クロム、酸化セリウム、α-酸化鉄、コランダム、窒化珪素、チタンカ-バイト、酸化チタン、二酸化珪素、酸化スズ、酸化マグネシウム、酸化タングステン、酸化ジルコニウム、窒化ホウ素、酸化亜鉛、炭酸カルシウム、硫酸カルシウム、硫酸バリウム、2硫化モリブデン、磁性酸化鉄の原料を脱水、アニール処理した針状α酸化鉄、必要によりそれらをアルミおよび/またはシリカで表面処理したもの等が挙げられる。
硬化剤としては、例えば、ポリイソシアネート等が挙げられる。ポリイソシアネートとしては、例えば、トリレンジイソシアネート(TDI)と活性水素化合物との付加体等の芳香族ポリイソシアネート、ヘキサメチレンジイソシアネート(HMDI)と活性水素化合物との付加体等の脂肪族ポリイソシアネート等が挙げられる。これらポリイソシアネートの重量平均分子量は、100~3000の範囲であることが望ましい。
防錆剤としては、例えばフェノール類、ナフトール類、キノン類、窒素原子を含む複素環化合物、酸素原子を含む複素環化合物、硫黄原子を含む複素環化合物等が挙げられる。
非磁性補強粒子として、例えば、酸化アルミニウム(α、βまたはγアルミナ)、酸化クロム、酸化珪素、ダイヤモンド、ガーネット、エメリー、窒化ホウ素、チタンカーバイト、炭化珪素、炭化チタン、酸化チタン(ルチル型またはアナターゼ型の酸化チタン)等が挙げられる。
下地層42は、基材41の表面の凹凸を緩和し、磁性層43の表面の凹凸を調整するためのものである。下地層42は、非磁性粉、結着剤および潤滑剤を含む非磁性層である。下地層42は、磁性層43の表面に潤滑剤を供給する。下地層42が、必要に応じて、帯電防止剤、硬化剤および防錆剤等のうちの少なくとも1種の添加剤をさらに含んでいてもよい。
非磁性粉は、例えば無機粒子粉または有機粒子粉の少なくとも1種を含む。また、非磁性粉は、カーボンブラック等の炭素粉を含んでいてもよい。なお、1種の非磁性粉を単独で用いてもよいし、2種以上の非磁性粉を組み合わせて用いてもよい。無機粒子は、例えば、金属、金属酸化物、金属炭酸塩、金属硫酸塩、金属窒化物、金属炭化物または金属硫化物等を含む。非磁性粉の形状としては、例えば、針状、球状、立方体状、板状等の各種形状が挙げられるが、これらの形状に限定されるものではない。
結着剤および潤滑剤は、上述の磁性層43と同様である。
帯電防止剤、硬化剤および防錆剤はそれぞれ、上述の磁性層43と同様である。
バック層44は、結着剤および非磁性粉を含む。バック層44が、必要に応じて潤滑剤、硬化剤および帯電防止剤等のうちの少なくとも1種の添加剤をさらに含んでいてもよい。結着剤および非磁性粉は、上述の下地層42と同様である。
tb[μm]=tT[μm]-tB[μm]
磁気テープ1の平均厚み(平均全厚)tTの上限値が、5.6μm以下、好ましくは5.0μm以下、より好ましくは4.6μm以下、さらにより好ましくは4.4μm以下である。磁気テープ1の平均厚みtTが5.6μm以下であると、1データカートリッジ内に記録できる記録容量を一般的な磁気テープよりも高めることができる。磁気テープ1の平均厚みtTの下限値は特に限定されるものではないが、例えば3.5μm以上である。
磁気テープ1の長手方向における磁性層43の保磁力Hc2の上限値が、好ましくは2000Oe以下、より好ましくは1900Oe以下、さらにより好ましくは1800Oe以下である。長手方向における磁性層43の保磁力Hc2が2000Oe以下であると、高記録密度であっても十分な電磁変換特性を有することができる。
磁気テープ1の垂直方向(厚み方向)における磁性層43の角形比S1が、好ましくは65%以上、より好ましくは70%以上、さらにより好ましくは75%以上、特に好ましくは80%以上、最も好ましくは85%以上である。角形比S1が65%以上であると、磁性粉の垂直配向性が十分に高くなるため、さらに優れた電磁変換特性(例えばSNR)を得ることができる。
る。
角形比S1(%)=(Mr/Ms)×100
バック面の表面粗度(バック層44の表面粗度)Rbが、Rb≦6.0[nm]であることが好ましい。バック面の表面粗度Rbが上記範囲であると、さらに優れた電磁変換特性を得ることができる。
以上の実施形態では、サーボパターン6を構成するサーボフレームSFの方位角傾斜(アジマス角)を12°としたが、これに限られず、例えば11°以上36°以下、好ましくは、11°以上26°以下とすることができる。また、上記方位角傾斜を「/」及び「\」の2種類としたが、これらとは傾斜角が異なる方位角傾斜がサーボパターンにさらに含まれてもよい。
(1) 磁気テープの磁性層の幅方向に間隔をおいて配列された複数のサーボバンドにサーボパターンを記録する方法であって、
前記磁気テープを所定のテンションで走行させ、
前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する
サーボパターン記録方法。
(2)上記(1)に記載のサーボパターン記録方法であって、
前記第1のピッチに対する前記第2のピッチの差分は、5μm以下である
サーボパターン記録方法。
(3)上記(2)に記載のサーボパターン記録方法であって、
前記第2のピッチは、2854.2μm以上2858.7μm以下である
サーボパターン記録方法。
(4)上記(1)~(3)のいずれか1つに記載のサーボパターン記録方法であって、
前記所定のテンションは、0.3N以上0.6N以下である
サーボパターン記録方法。
(5) 磁気テープの磁性層の幅方向に間隔をおいて配列された複数のサーボバンドにサーボパターンを記録する装置であって、
前記複数のサーボバンドに対応して配置された複数の記録部を有するサーボライトヘッドを具備し、
前記複数の記録部は、前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する磁気ギャップをそれぞれ有する
サーボパターン記録装置。
(6)上記(5)に記載のサーボパターン記録装置であって、
前記第1のピッチに対する前記第2のピッチの差分は、5μm以下である
サーボパターン記録装置。
(7)上記(6)に記載のサーボパターン記録装置であって、
前記第2のピッチは、2854.2μm以上2858.7μm以下である
サーボパターン記録装置。
(8) 幅方向に間隔をおいて配列された複数のサーボバンドを有する磁性層を備えた磁気テープの製造方法であって、
前記磁気テープを所定のテンションで走行させ、
前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する
磁気テープの製造方法。
(9)上記(8)に記載の磁気テープの製造法方法であって、
前記第1のピッチに対する前記第2のピッチの差分は、5μm以下である
磁気テープの製造方法。
(10)上記(8)又は(9)に記載の磁気テープの製造方法であって、
前記第2のピッチは、2854.2μm以上2858.7μm以下である
磁気テープの製造方法。
(11) 幅方向に間隔をおいて配列された複数のサーボバンドを有する磁性層を具備し、
前記磁性層は、隣接する2つのサーボバンド間の距離であるサーボバンドピッチが、前記磁性層に情報を記録し又は前記磁性層に記録された情報を再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔よりも狭い領域を、少なくとも一部に有する
磁気テープ。
(12)上記(11)に記載の磁気テープであって、
前記領域におけるサーボバンドピッチと、前記2つのサーボリードヘッドの配置間隔との差分は、0.1μm以上4.6μm以下である
磁気テープ。
(13)上記(12)に記載の磁気テープであって、
前記領域におけるサーボバンドピッチと、前記2つのサーボリードヘッドの配置間隔との差分は、0.5μm以上4.6μm以下である
磁気テープ。
(14) カートリッジケースと、
前記カートリッジケースの内部に回転可能に収容されたテープリールと、
前記テープリールに巻き付けられた磁気テープと
を具備し、
前記磁気テープは、テープ幅方向に間隔をおいて記録された複数のサーボパターンが記録された磁性層を有し、
前記磁性層は、
隣接する2つのサーボバンド間の距離であるサーボバンドピッチが、前記磁性層に情報を記録し又は前記磁性層に記録された情報を再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔よりも狭い第1の領域と、
前記サーボバンドピッチが前記2つのサーボリードヘッドの配置間隔よりも広い第2の領域と、を有する
テープカートリッジ。
(15)上記(14)に記載のテープカートリッジであって、
前記第1の領域は、前記テープリールに巻回された前記磁気テープの外周側の第1の端部側の領域であり、
前記第2の領域は、前記テープリールに巻回された前記磁気テープの内周側の第2の端部の領域である
テープカートリッジ。
(16)上記(15)に記載のテープカートリッジであって、
前記磁性層のサーボバンドピッチは、前記磁気テープの前記第1の端部側から前記第2の端部側に向かって漸次広くなる
テープカートリッジ。
6…サーボパターン
10…テープカートリッジ
11…カートリッジケース
13…テープリール
30…テープドライブ装置
36…ドライブヘッド
43…磁性層
100…サーボパターン記録装置
113…サーボライトヘッド
132…サーボリードヘッド
601,602…サーボパターン
Claims (16)
- 磁気テープの磁性層の幅方向に間隔をおいて配列された複数のサーボバンドにサーボパターンを記録する方法であって、
前記磁気テープを所定のテンションで走行させ、
前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する
サーボパターン記録方法。 - 請求項1に記載のサーボパターン記録方法であって、
前記第1のピッチに対する前記第2のピッチの差分は、5μm以下である
サーボパターン記録方法。 - 請求項2に記載のサーボパターン記録方法であって、
前記第2のピッチは、2854.2μm以上2858.7μm以下である
サーボパターン記録方法。 - 請求項1に記載のサーボパターン記録方法であって、
前記所定のテンションは、0.3N以上0.6N以下である
サーボパターン記録方法。 - 磁気テープの磁性層の幅方向に間隔をおいて配列された複数のサーボバンドにサーボパターンを記録する装置であって、
前記複数のサーボバンドに対応して配置された複数の記録部を有するサーボライトヘッドを具備し、
前記複数の記録部は、前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する磁気ギャップをそれぞれ有する
サーボパターン記録装置。 - 請求項5に記載のサーボパターン記録装置であって、
前記第1のピッチに対する前記第2のピッチの差分は、5μm以下である
サーボパターン記録装置。 - 請求項6に記載のサーボパターン記録装置であって、
前記第2のピッチは、2854.2μm以上2858.7μm以下である
サーボパターン記録装置。 - 幅方向に間隔をおいて配列された複数のサーボバンドを有する磁性層を備えた磁気テープの製造方法であって、
前記磁気テープを所定のテンションで走行させ、
前記磁性層にデータを記録し又は前記磁性層に記録されたデータを再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔である第1のピッチよりも狭い第2のピッチで、前記複数のサーボバンドにサーボパターンを記録する
磁気テープの製造方法。 - 請求項8に記載の磁気テープの製造法方法であって、
前記第1のピッチに対する前記第2のピッチの差分は、5μm以下である
磁気テープの製造方法。 - 請求項8に記載の磁気テープの製造方法であって、
前記第2のピッチは、2854.2μm以上2858.7μm以下である
磁気テープの製造方法。 - 幅方向に間隔をおいて配列された複数のサーボバンドを有する磁性層を具備し、
前記磁性層は、隣接する2つのサーボバンド間の距離であるサーボバンドピッチが、前記磁性層に情報を記録し又は前記磁性層に記録された情報を再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔よりも狭い領域を、少なくとも一部に有する
磁気テープ。 - 請求項11に記載の磁気テープであって、
前記領域におけるサーボバンドピッチと、前記2つのサーボリードヘッドの配置間隔との差分は、0.1μm以上4.6μm以下である
磁気テープ。 - 請求項12に記載の磁気テープであって、
前記領域におけるサーボバンドピッチと、前記2つのサーボリードヘッドの配置間隔との差分は、0.5μm以上4.6μm以下である
磁気テープ。 - カートリッジケースと、
前記カートリッジケースの内部に回転可能に収容されたテープリールと、
前記テープリールに巻き付けられた磁気テープと
を具備し、
前記磁気テープは、テープ幅方向に間隔をおいて記録された複数のサーボパターンが記録された磁性層を有し、
前記磁性層は、
隣接する2つのサーボバンド間の距離であるサーボバンドピッチが、前記磁性層に情報を記録し又は前記磁性層に記録された情報を再生するテープドライブ装置における2つのサーボリードヘッドの配置間隔よりも狭い第1の領域と、
前記サーボバンドピッチが前記2つのサーボリードヘッドの配置間隔よりも広い第2の領域と、を有する
テープカートリッジ。 - 請求項14に記載のテープカートリッジであって、
前記第1の領域は、前記テープリールに巻回された前記磁気テープの外周側の第1の端部側の領域であり、
前記第2の領域は、前記テープリールに巻回された前記磁気テープの内周側の第2の端部側の領域である
テープカートリッジ。 - 請求項15に記載のテープカートリッジであって、
前記磁性層のサーボバンドピッチは、前記磁気テープの前記第1の端部側から前記第2の端部側に向かって漸次広くなる
テープカートリッジ。
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US20130182346A1 (en) * | 2012-01-12 | 2013-07-18 | Donald J. Fasen | Tape head length adjustment |
JP2020155188A (ja) * | 2019-03-22 | 2020-09-24 | 富士フイルム株式会社 | 磁気テープカートリッジおよび磁気テープ装置 |
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Title |
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ANONYMOUS: "Standard ECMA-319 Data Interchange on 12,7 mm 384-Track Magnetic Tape Cartridges – Ultrium-1 Format Brief History", ECMA, 30 June 2001 (2001-06-30), XP055967203, Retrieved from the Internet <URL:https://www.ecma-international.org/wp-content/uploads/ECMA-319_1st_edition_june_2001.pdf> * |
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