Magnetic recording medium and tape cartridge

Abstract

A magnetic recording medium according to one embodiment of the present technology includes a magnetic tape and a reinforcing part. The magnetic tape includes, in each of a plurality of servo bands extending in a tape longitudinal direction and arranged in a tape width direction, a magnetic layer in which a servo pattern is recorded, the servo pattern including a first azimuth angle incline inclined with respect to the tape width direction and a second azimuth angle incline inclined in a direction different from the first azimuth angle incline with respect to the tape width direction, the first azimuth angle inclination and the second azimuth angle inclination being asymmetric with respect to the tape width direction. The magnetic tape is fixed to a leader pin, on one end thereof in the tape longitudinal direction. The average thickness of the magnetic tape is 5.3 μm or less. The reinforcement part is provided at a position where the magnetic tape is fixed to the leader pin, on the one end of the magnetic tape in the tape longitudinal direction, and reinforces the magnetic tape.

Description

Magnetic recording media and tape cartridges

[0001] The present technology relates to a magnetic recording medium having a leader tape and a tape cartridge including the same.

[0002] Magnetic recording media having a magnetic layer with a plurality of data bands on which data is recorded and a plurality of servo bands on which servo patterns are recorded are widely known (see, for example, Patent Document 1). Magnetic recording media are also known in which a leader tape having an engagement portion that engages with a take-up reel of a tape drive device is attached to the leading end of the magnetic tape (see, for example, Patent Document 2). Furthermore, it is known that the servo pattern has an asymmetric shape with respect to the tape width direction in order to obtain a highly reliable servo pattern signal (see, for example, Patent Document 3).

[0003] Japanese Patent Application Laid-Open No. 2014-199706 International Publication No. 2023 / 013144 Japanese Patent Application Laid-Open No. 2023-67268

[0004] As magnetic recording media have become thinner and have higher capacities in recent years, it is expected that the data tracks on magnetic recording media will become narrower. Therefore, in order to improve the tracking accuracy of the data tracks, it is considered effective to make the servo pattern asymmetric in the tape width direction, as described in Patent Document 3.

[0005] However, by making the servo pattern asymmetric in this way, new issues regarding recording characteristics have come to light that were not an issue with magnetic recording media on which servo patterns having conventional pattern shapes that are symmetrical with respect to the tape width direction have been recorded.

[0006] In view of the above circumstances, an object of the present technology is to provide a magnetic recording medium and a tape cartridge that can ensure the reliability of recording characteristics even when the magnetic recording medium and the tape cartridge have a servo pattern that is asymmetric in shape with respect to the tape width direction.

[0007] According to one aspect of the present technology, there is provided a magnetic recording medium comprising a magnetic tape and a reinforcing section. The magnetic tape has a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt inclined with respect to the tape width direction and a second azimuth tilt inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and the first azimuth tilt and the second azimuth tilt are asymmetric with respect to the tape width direction, in each of a plurality of servo bands extending in a tape longitudinal direction and arranged in a tape width direction. One end side of the tape in the tape longitudinal direction is fixed to a leader pin, and the reinforcing section has an average thickness of 5.3 μm or less. The reinforcing section is provided at the one end side of the magnetic tape in the tape longitudinal direction at a position where the magnetic tape is fixed to the leader pin, and reinforces the magnetic tape.

[0008] According to another aspect of the present technology, a magnetic recording medium includes a magnetic tape, a leader tape, and a splice tape. The magnetic tape has a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt inclined with respect to the tape width direction and a second azimuth tilt inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and the first azimuth tilt and the second azimuth tilt are asymmetric with respect to the tape width direction, in each of a plurality of servo bands extending in the tape longitudinal direction and arranged in the tape width direction. The leader tape is connected to the magnetic tape in the tape longitudinal direction. The splice tape connects the magnetic tape and the leader tape. The average thickness of the magnetic tape is 5.3 μm or less. When a joint height difference is defined as the difference between a joint thickness, which is the sum of the thicknesses of the leader tape and the splice tape, and the thickness of the magnetic tape, the ratio of the joint height difference to the thickness of the magnetic tape is 5 or less.

[0009] 1 is an exploded perspective view of a tape cartridge; FIG. 1 is a plan view of a magnetic recording medium according to a first embodiment of the present technology when viewed from its thickness direction; FIG. 2 is a side view of the magnetic recording medium when viewed from its width direction; FIG. 3 is a schematic view of a magnetic tape constituting the magnetic recording medium when viewed from the side (width direction); FIG. 4 is a schematic view of the magnetic tape when viewed from the magnetic layer side; FIG. 5 is a schematic view of a leader tape constituting the magnetic recording medium when viewed from the side (width direction); FIG. 6 is a diagram of a data recording and reproducing device; FIG. 7 is a schematic view of a data write head in the data recording and reproducing device; 14 is a cross-sectional view taken along line A-A in FIG. 13, showing the connecting portion of the leader pin and the magnetic recording medium. FIG. 15 is a diagram for explaining the upper limit of the length of the second margin, showing the state when the magnetic recording medium is being wound by the winding roller. FIG. 16 is an enlarged perspective view showing the state when the magnetic recording medium according to the comparative example is fixed to the leader pin with a clamper. FIG. 17 is a cross-sectional side view showing the connecting portion of the magnetic recording medium and the leader pin according to the comparative example. FIG. 18 is a graph plotting the relationship between the step-to-magnetic tape ratio (A / E) and the R vs. PES BOT 100 m average value (PES average value) for Experimental Examples 1 to 4 in Table 2. FIG. 19 is a cross-sectional side view showing the connecting portion of the magnetic recording medium and the leader pin according to the first modified example. FIG. 19 is a cross-sectional side view showing the connecting portion of the magnetic recording medium and the leader pin according to the second modified example.

[0010] Hereinafter, embodiments of the present technology will be described with reference to the drawings.

[0011] 1 is an exploded perspective view of a tape cartridge 50 according to an embodiment of the present technology. The tape cartridge 50 of this embodiment will be described below using a magnetic tape cartridge conforming to the LTO (Linear Tape Open) standard as an example.

[0012] The tape cartridge 50 of this embodiment has a configuration in which a single tape reel 54 with a magnetic recording medium 1 wound thereon is rotatably housed inside a cartridge case 53 formed by joining an upper shell 51 and a lower shell 52 with multiple screw members.

[0013] The tape reel 54 has a cylindrical reel hub 55 with a bottom, a lower flange 56 integrally formed at the lower end of the reel hub 55, and an upper flange 57 joined to the upper end of the reel hub 55, each of which is formed from an injection-molded synthetic resin material.

[0014] Although not shown, an annular chucking gear is formed in the center of the underside of tape reel 54 for engaging with spindle 11 (see FIG. 8) of data recording / reproducing device 100. This chucking gear is exposed to the outside through an opening 58 provided in the center of lower shell 52. On the inner periphery of this chucking gear, an annular metal plate 59 that magnetically attracts spindle 11 is fixed to the bottom outer surface of reel hub 55 by insert molding.

[0015] A reel lock mechanism is provided inside the reel hub 55 to prevent rotation of the tape reel 54 when the tape cartridge 50 is not in use. The reel lock mechanism includes a plurality of gear-forming walls 60 erected on the upper surface of the bottom of the reel hub 55, a reel lock member 61 having engaging teeth on its lower surface that mesh with gear portions formed on the upper surfaces of the gear-forming walls 60, a reel lock release member 62 for releasing the engagement between the gear-forming walls 60 and the reel lock member 61, and a reel spring 63 provided between the inner surface of the upper shell 51 and the upper surface of the reel lock member 61. The reel spring 63 is a coil spring that urges the tape reel 54 toward the lower shell 52 via the reel lock member 61.

[0016] When the cartridge is in use, the reel lock release member 62 is pressed upward by the spindle 11 (see FIG. 8) of the data recording / reproducing device 100 which engages with the chucking gear, causing the reel lock member 61 to move to the unlocked position against the biasing force of the reel spring 63. The reel lock member 62 is configured to be rotatable relative to the reel lock member 61 together with the tape reel 54.

[0017] One side wall 64 of the cartridge case 53 is provided with a drawer opening 65 for drawing out one end of the magnetic recording medium 1 to the outside. A slide door 66 for opening and closing the drawer opening 65 is disposed inside the side wall 64. The slide door 66 is configured to slide in the direction of opening the drawer opening 65 against the biasing force of a torsion spring 67 by engaging with a tape loading mechanism (not shown) of the data recording and reproducing device 100.

[0018] A leader pin 68 is fixed to one end of the magnetic recording medium 1. The leader pin 68 corresponds to an engaging portion that is pulled out from the pull-out opening 65 and engages with the take-up reel 12 (see FIG. 8) of the data recording and reproducing device 100 during recording and reproducing of the tape cartridge 50. The leader pin 68 is configured to be detachable from a pin holding portion 69 provided on the inside of the pull-out opening 65. The pin holding portions 69 are attached to the inner surfaces of the upper shell 51 and the lower shell 52, respectively, and are configured to be able to elastically hold the upper and lower ends of the leader pin 68, respectively.

[0019] Inside the cartridge case 53, there is disposed a safety tab 70 for preventing accidental erasure of information recorded on the magnetic recording medium 1, as well as a cartridge memory 71 that can contactlessly read and write the contents of the information recorded on the magnetic recording medium 1. The cartridge memory 71 is composed of a contactless communication medium having an antenna coil, an IC chip, etc. mounted on a substrate.

[0020] [Magnetic Recording Medium] Fig. 2 is a plan view of the magnetic recording medium 1 as viewed in its thickness direction, and Fig. 3 is a side view of the magnetic recording medium 1 as viewed in its width direction. In this specification, the coordinate system based on the magnetic recording medium 1 will be represented by an XYZ coordinate system. Here, the X-axis direction corresponds to the longitudinal direction of the magnetic recording medium 1, the Y-axis direction corresponds to the width direction of the magnetic recording medium, and the Z-axis direction corresponds to the thickness direction of the magnetic recording medium.

[0021] The magnetic recording medium 1 includes a magnetic tape MT, a leader tape LT, and a splice tape ST.

[0022] The magnetic tape MT is a main component of the magnetic recording medium 1 wound around the reel hub 55 of the tape reel 54, and is the portion on which various information can be magnetically recorded. The magnetic tape MT is a long tape portion having an end of tape (EOT) on the inner circumferential side wound around the reel hub 55 and a start of tape (BOT) on the opposite outer circumferential side, and its length is, for example, 1000 m or more, and its average thickness is, for example, 5.3 μm or less.

[0023] The leader tape LT is connected to the magnetic tape MT in the tape longitudinal direction. The leader tape LT has a terminal end that is connected to the starting end of the magnetic tape MT, and a starting end to which a leader pin 68 is fixed. The leader pin 68 is fixed to the starting end of the leader tape by a clamp member 72 that has a substantially C-shaped cross section. The width of the leader tape LT is the same or nearly the same (½ inch) as the width of the magnetic tape MT, and its length is typically 900 mm. The average thickness of the leader tape LT is, for example, 18 μm or less, and it is stronger than the magnetic tape MT.

[0024] The splice tape ST is attached to the surface of the leading end of the magnetic tape MT and the trailing end of the leader tape LT, which are opposed to each other in the tape longitudinal direction, thereby connecting the magnetic tape MT and the leader tape LT. The length of the splice tape ST is, for example, 14 mm. The connection length of the splice tape ST to the leading end of the magnetic tape MT and the trailing end of the leader tape LT is, for example, 6 mm to 8 mm. The width of the splice tape ST is, for example, 12.2 mm, and its thickness is, for example, 5.0 μm to 24 μm. The splice tape ST is composed of an adhesive tape having a plastic base material such as PET and an adhesive layer such as an acrylic adhesive provided on one main surface of the base material.

[0025] The dimensions indicated by A to E in FIG. 3 will be described later.

[0026] (Magnetic Tape) Next, the magnetic tape MT will be described in detail.

[0027] Fig. 4 is a schematic diagram of the magnetic tape MT as seen from the side (width direction), and Fig. 5 is a schematic diagram of the magnetic tape MT as seen from above (the magnetic layer 4 side). As shown in Figs. 4 and 5, the magnetic tape MT is configured as a tape that 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).

[0028] The width (Y-axis direction) of the magnetic tape MT is typically about 1 / 2 inch, but may be about 1 inch, and the size can be changed as appropriate.

[0029] The magnetic tape MT includes a tape-shaped substrate 2 that is long in the longitudinal direction (X-axis direction), an underlayer 3 (non-magnetic layer) provided on one main surface of the substrate 2, a magnetic layer 4 provided on the underlayer 3, and a back layer 5 provided on the other main surface of the substrate 2.

[0030] The back layer 5 may be provided as needed, and may be omitted. The magnetic layer 4 may be a vertically oriented type or a longitudinally oriented type. The magnetic layer 4 may be a coated film of a magnetic material, or a vapor-deposited or sputtered film of a magnetic material. Details of each layer constituting the magnetic tape MT will be described later.

[0031] 4, the magnetic layer 4 has a plurality of data bands d (data bands d0 to d3) in which data is written, and a plurality of servo bands s (servo bands s0 to s4) in which servo patterns 7 are written. Each of the plurality of data bands d and the plurality of servo bands s is long in the longitudinal direction (X-axis direction) and short in the width direction (Y-axis direction). The servo bands s are arranged at positions sandwiching each data band d in the width direction (Y-axis direction).

[0032] 4 shows an example in which the number of data bands d is 4 and the number of servo bands s is 5. Note that the number of data bands d and the number of servo bands s can be changed as appropriate.

[0033] The ratio of the area of ​​the servo bands s to the entire surface area of ​​the magnetic layer 4 is, for example, 4.0% or less. The width of the servo bands s is, for example, 96 μm or less for a ½ inch tape width. The ratio of the area of ​​the servo bands s to the entire surface area of ​​the magnetic layer 43 can be measured, for example, by developing the magnetic tape MT with a developer such as a ferricolloid developer, and then observing the developed magnetic tape MT with an optical microscope.

[0034] The data band d includes a plurality of recording tracks 6 that are long in the longitudinal direction and aligned in the width direction. The number of recording tracks 6 included in one data band d is, for example, about 2,000 to 10,000. Data is recorded along and within these recording tracks 6. The length of one bit in the longitudinal direction of the data recorded in the data band d is, for example, 48 nm or less. The off-track margin of the data band d is, for example, 300 nm or less.

[0035] The width of the recording track 6 (track pitch: Y-axis direction) is, for example, 1.0 μm or less, and in this embodiment, 800 nm or less, or 500 nm or less.

[0036] The width of the recording track 6 is determined as follows: First, a cartridge 50 is prepared on which data is recorded all over the surface of the magnetic tape MT, and the magnetic tape MT is unwound from the cartridge 50. A sample is then cut out of the magnetic tape MT to a length of 250 mm at a position 30 to 40 m longitudinally from one end of the outer periphery of the magnetic tape MT.

[0037] Next, the data recording pattern in the data band DB portion of the magnetic layer 4 of the sample is observed using a magnetic force microscope (MFM), and an MFM image is obtained. The MFM used is a Digital Instruments Dimension3100 and its analysis software. The measurement area of ​​the MFM image is 10 μm × 10 μm, and this 10 μm × 10 μm measurement area is divided into 512 × 512 (= 262,144) measurement points. Measurements are performed using the MFM on three 10 μm × 10 μm measurement areas in different locations, resulting in three MFM images.

[0038] The track width was measured at 10 locations on each of the three MFM images obtained, resulting in a total of 30 measurement values, and the average (simple average) of the 30 measurement values ​​was calculated. This average value is the recording track width. The analysis software included with the Dimension3100 was used to measure the track width. The MFM measurement conditions were: sweep speed: 1 Hz, tip used: MFMR-20, lift height: 20 nm, and correction: Flatten order 3.

[0039] Alternatively, a method using the data write head 20 (see FIG. 9 described later) may be used to measure the recording track width. In this case, to ignore fluctuations during the running of the magnetic tape MT, the data write head 20 is set to recording and reproducing mode, and the recording track width can be measured from the change in output when the azimuth angle θ of the data write head 20 is changed. (IEEE_Sept1996_Crosstrack Profiles of Thin Film MR Tape Heads Using the Azimuth Displacement Method)

[0040] In this example, data is recorded so that adjacent recording tracks do not overlap, but the data recording method for the recording tracks is not limited to this example. For example, data may be recorded by shingled magnetic recording (SMR) so that adjacent recording tracks partially overlap in the width direction of the magnetic tape MT.

[0041] The servo band s includes a servo pattern 7 of a predetermined shape that is recorded by a servo recording and reproducing device (not shown). The servo pattern 7 includes an A burst 7a, a B burst 7b, a C burst 7c, and a D burst 7d. The A burst 7a and the C burst 7c each include a plurality of first azimuth angle inclinations inclined in a first direction " / ", with the number of the A burst 7a being four and the number of the C burst 7c being five. On the other hand, the C burst 7b and the D burst 7d each include a plurality of second azimuth angle inclinations inclined in a second direction "\" different from the first direction, with the number of the B burst 7b being four and the number of the D burst 7d being five.

[0042] 6A and 6B are schematic diagrams showing examples of the shape of a servo pattern 7. In the case of a typical servo pattern 7R as shown in Fig. 6A, the A burst 7a and the B burst 7b, and the C burst 7c and the D burst 7d are in a symmetrical (line-symmetric) positional relationship with respect to the symmetry axis Ys, which is parallel to a reference line Ly parallel to the width direction (Y-axis direction) of the magnetic tape MT. The angle formed by the symmetry axis Ys and each burst in this case is also called the azimuth angle, and an example with an azimuth angle of 12° is shown in the same figure.

[0043] 6B, the servo pattern 7 in this embodiment has a symmetry axis Ys tilted 10° counterclockwise with respect to the reference line Ly, and the A bursts 7a and B bursts 7b, and the C bursts 7c and D bursts 7d are asymmetric with respect to the tape width direction (reference line Ly). The figure shows an example in which the azimuth angle of the A bursts 7a and C bursts 7c is 2°, and the azimuth angle of the B bursts 7b and D bursts 7d is 22°.

[0044] The tilt angle (azimuth reference angle) of the symmetry axis Ys with respect to the reference line Ly is not limited to 10°, and may be, for example, 8° or more. As for the degree of asymmetry between the A burst 7a and the B burst 7b and the C burst 7c and the D burst 7d as described above, for example, the difference between the length of the first azimuth tilt constituting the A burst 7a and the C burst 7c and the length of the second azimuth tilt constituting the B burst 7b and the D burst 7d may be, for example, 3 μm or more.

[0045] The shape of the servo pattern 7 can be measured, for example, by developing the magnetic layer 4 of the magnetic tape MT using a developer such as a ferricolloid developer, and then observing the developed magnetic layer 4 of the magnetic tape MT with an optical microscope.

[0046] With each generation of LTO-standard magnetic tape MT, the number of recording tracks 6 has increased, dramatically improving recording capacity. For example, the original LTO-1 had 384 recording tracks 6, but the numbers of recording tracks 6 for LTO-2 to LTO-9 have increased to 512, 704, 896, 1280, 2176, 3584, 6656, and 8960, respectively. Similarly, data recording capacity was 100 GB (gigabytes) for LTO-1, but increased to 200 GB, 400 GB, 800 GB, 1.5 TB (terabytes), 2.5 TB, 6.0 TB, 12 TB, and 18 TB, respectively, for LTO-2 to LTO-9.

[0047] In this embodiment, the number of recording tracks 6 and the recording capacity are not particularly limited and can be changed as appropriate. However, it is advantageous to apply this technology to cases where the number of recording tracks 6 and the recording capacity are large (for example, 6656 or more tracks, 12 TB or more: LTO8 or later) and servo patterns 7 and data must be recorded strictly and accurately on the magnetic tape MT.

[0048] (Leader Tape) Figure 7 is a schematic diagram of the leader tape LT as seen from the side (width direction). As shown in Figures 4 and 5, the leader tape LT is configured as a tape that 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). The width of the leader tape LT (Y-axis direction) is typically approximately the same as the width of the magnetic tape MT, and in this embodiment is about 1 / 2 inch.

[0049] Like the magnetic tape MT, the leader tape LT has a laminated structure in which multiple layers are stacked. Specifically, the leader tape LT has a long tape-like substrate 82, an underlayer 83 provided on one main surface of the substrate 82, a magnetic layer 84 provided on the underlayer 83, and a back layer 85 provided on the other main surface of the substrate 82. When the leader tape LT runs over the magnetic head, the surface of the magnetic layer 84 slides over the surface of the magnetic head. Note that the underlayer 83 and the back layer 85 are provided as needed and are not necessarily required.

[0050] Furthermore, since the leader tape LT has a magnetic layer 84, it is possible to pre-record an identification signal that identifies it as the leader tape LT on the magnetic layer 84. This makes it possible to prevent, for example, the mistaken recording of data on the leader tape LT. Furthermore, the leader tape LT has a structure in which multiple layers, such as the underlayer 83 and magnetic layer 84, are laminated on the substrate 82, thereby minimizing the difference in sliding characteristics compared to the magnetic tape MT. This allows the leader tape LT to have a friction coefficient that is more suitable for running than a tape consisting of only the substrate 82. This allows the leader tape LT to run more smoothly. It also reduces charging during sliding of the magnetic head.

[0051] The configurations of the substrate 82, underlayer 83, magnetic layer 84, and back layer 85 of the leader tape LT can be substantially the same as the configurations of the substrate 2, underlayer 3, magnetic layer 4, and back layer 5 of the magnetic tape MT. However, the configurations of the substrate 82, underlayer 83, magnetic layer 84, and back layer 85 of the leader tape LT may be different from the configurations of the substrate 2, underlayer 3, magnetic layer 4, and back layer 5 of the magnetic tape MT, respectively. For example, even if the underlayer 3 of the magnetic tape MT uses an acicular inorganic material, the underlayer 83 of the leader tape LT may use an inorganic material other than an acicular inorganic material.

[0052] The average thickness (average total thickness) of the leader tape LT is, for example, 5.0 μm or more and 18.0 μm or less, which is thicker than the average thickness of the magnetic tape MT. The difference between the average thickness of the leader tape LT and the average thickness of the magnetic tape MT is, for example, 12 μm or less. The thickness of the substrate 82 is, for example, 3.0 μm or more and 15.0 μm or less. The thickness of the underlayer 83 is, for example, 0.6 μm or more and 3.0 μm or less. The thickness of the magnetic layer 84 is, for example, 0.05 μm or more and 0.30 μm or less. The thickness of the back layer 85 is, for example, 0.2 μm or more and 1.0 μm or less.

[0053] The average thickness of the leader tape LT is determined, for example, by the same method (described later) as that for the average thickness of the magnetic tape MT. The same number of measurement samples for measuring the average thickness of the leader tape LT are taken from the vicinity of the measurement samples taken when measuring the Young's modulus in the longitudinal direction.

[0054] (Data Recording / Reproducing Device) Figure 8 is a diagram showing a data recording / reproducing device 100 which is a tape drive device. In this specification, a coordinate system based on the data recording / reproducing device 100 will be represented as an X'Y'Z' coordinate system. The data recording / reproducing device 100 is capable of recording data on a magnetic tape MT, and is also capable of reproducing data recorded on the magnetic tape MT.

[0055] The data recording and reproducing device 100 is configured to be able to load a tape cartridge 50. The tape cartridge 50 is configured to be able to rotatably accommodate a wound magnetic tape MT (magnetic recording medium 1) therein. The data recording and reproducing device 100 may be configured to be able to load one tape cartridge 50, or may be configured to be able to load multiple tape cartridges 50 simultaneously.

[0056] The data recording and reproducing device 100 comprises a spindle 11, a take-up reel 12, a spindle drive unit 13, a reel drive unit 14, a data write head 20, a control unit 15, a width measurement unit 16, an angle adjustment unit 17, and a plurality of guide rollers 18.

[0057] The spindle 11 is configured so that its rotation can rotate the tape reel 54 housed inside the cartridge 10. The spindle drive device 13 rotates the spindle 11 in response to a command from the control device 15.

[0058] The take-up reel 12 is configured to be able to fix the leading end (leader pin 68) of the magnetic recording medium 1 pulled out from the tape cartridge 50 via a tape loading mechanism (not shown). The reel drive device 14 rotates the take-up reel 12 in response to a command from the control device 15.

[0059] The plurality of guide rollers 18 guide the running of the magnetic recording medium 1 so that the transport path formed between the tape cartridge 50 and the take-up reel 12 has a predetermined relative positional relationship with the data write head 20 .

[0060] The data write head 20 is configured to be able to record data onto the data band d (recording track 6) of the magnetic tape MT in response to a command from the control device 15 when the magnetic tape MT passes underneath the data write head 20, and is also configured to be able to play back the recorded data.

[0061] When data is recorded on or reproduced from the magnetic tape MT by the data write head 20, the spindle 11 and take-up reel 12 are rotated by the spindle drive device 13 and the reel drive device 14, causing the magnetic tape MT to run. The magnetic tape MT can run in the forward direction (the direction in which it unwinds from the spindle 11 side to the take-up reel 12 side, Fwd direction) indicated by the arrow A1 in Figure 8, and in the reverse direction (the direction in which it rewinds from the take-up reel 12 side to the spindle 11 side, Rvs direction) indicated by the arrow A2.

[0062] The data write head 20 is capable of recording / reproducing data in both the forward and reverse running directions of the magnetic tape MT. In particular, in this embodiment, the data write head 20 is disposed so that its longitudinal direction (Y'-axis direction) is inclined at a predetermined angle θ (first head azimuth angle θ) with respect to the width direction (Y-axis direction) of the magnetic tape MT (see FIG. 9 , described later). In the description of this embodiment, the angle at which the longitudinal direction (Y'-axis direction) of the data write head 20 is inclined with respect to the width direction (Y-axis direction) of the magnetic tape MT is referred to as the azimuth angle θ of the data write head 20. Details of the configuration of the data write head 20 will be described later with reference to FIG. 4 and other figures.

[0063] The width measurement unit 16 is configured to be able to measure the width of the magnetic tape MT when the magnetic tape MT passes below the width measurement unit 16. In other words, the width measurement unit 16 is configured to be able to measure the width of the magnetic tape MT when the data write head 20 records / reproduces data on / from the magnetic tape MT. The width measurement unit 16 measures the width of the magnetic tape MT and transmits the measured width to the control device 15.

[0064] The width measurement unit 16 is composed of various sensors such as an optical sensor. Any sensor capable of measuring the width of the magnetic tape MT may be used as the width measurement unit 16. The width of the magnetic tape MT can also be predicted by reading adjacent servo patterns 7 and determining the difference in position signals. In this case, the width measurement unit 16 can be omitted.

[0065] The angle adjustment unit 17 is configured to be able to hold the data write head 20 rotatably around an axis (Z axis) in the vertical direction. The angle adjustment unit 17 is configured to be able to adjust the azimuth angle θ of the data write head 20 in response to a command from the control device 15.

[0066] The control device 15 includes, for example, a control unit, a storage unit, a communication unit, etc. The control unit is configured by, for example, a CPU (Central Processing Unit) etc., and controls each unit of the data recording / reproducing device 100 in an integrated manner in accordance with a program stored in the storage unit.

[0067] The storage unit includes a non-volatile memory for storing various data and programs, and a volatile memory used as a work area for the control unit. The various programs may be read from a portable recording medium such as an optical disk or semiconductor memory, or may be downloaded from a server device on a network. The communication unit is configured to be able to communicate with other devices such as a PC (Personal Computer) or a server device.

[0068] In this embodiment, the control device 15 (control unit) acquires information about the width of the magnetic tape MT from the width measurement unit 16 (or predicts the width of the magnetic tape from the servo signal), and adjusts the azimuth angle θ (see Figure 9) of the data write head 20 using the angle adjustment unit 17 based on the information about the width of the magnetic tape MT.

[0069] In this embodiment, variations in the width of the magnetic tape MT are accommodated by adjusting the azimuth angle θ of the data write head 20. Typically, when the width of the magnetic tape MT becomes relatively wider, the azimuth angle θ of the data write head 20 is decreased, and conversely, when the width of the magnetic tape MT becomes relatively narrower, the azimuth angle θ of the data write head 20 is increased. The width of the magnetic tape MT may vary for various reasons, such as temperature, humidity, and tension applied to the magnetic tape MT in the longitudinal direction.

[0070] (Data Write Head) Next, a detailed description will be given of the configuration of the data write head 20. Fig. 9 is a schematic diagram of the data write head 20 as viewed from below (the back layer 5 side).

[0071] In the description of the data write head 20, the longitudinal direction of the data write head 20 is defined as the Y'-axis direction, the width direction of the data write head 20 as the X'-axis direction, and the up-down direction of the data write head 20 as the Z'-axis direction. The longitudinal direction (running direction) of the magnetic tape MT is defined as the X-axis direction, the width direction of the magnetic tape MT as the Y-axis direction, and the thickness direction of the magnetic tape MT as the Z-axis direction. The direction of the magnetic tape MT is based on the direction of the magnetic tape MT when it passes below the data write head 20.

[0072] 9, the data write head 20 includes a first data write head 20a and a second data write head 20b. In the description herein, when there is no particular distinction between the two data write heads 20, they are collectively referred to simply as the data write heads 20, and when there is a particular distinction between the two data write heads 20, they are referred to as the first data write head 20a and the second data write head 20b.

[0073] The first data write head 20a and the second data write head 20b are basically configured similarly, but are symmetrical in the width direction (Y'-axis direction) of the data write head 20. The first data write head 20 and the second data write head 20 are movable together in the width direction (Y-axis direction) of the magnetic tape MT, which allows data to be written to any one of the data bands d0 to d3.

[0074] The first data write head 20a is used when the magnetic tape MT is running in the forward direction (direction A1 in FIG. 8), while the second data write head 20b is used when the magnetic tape MT is running in the reverse direction (direction A2 in FIG. 8).

[0075] The data write head 20 has a facing surface 21 that faces the magnetic tape MT. The facing surface 21 is long in the longitudinal direction (Y'-axis direction) of the data write head 20 and short in the width direction (X'-axis direction) of the data write head 20. The facing surface 21 is provided with two servo read portions 22 and a plurality of data write / read portions 23.

[0076] The servo read sections 22 are provided one on each end in the longitudinal direction (Y′-axis direction) of the data write head 20. The servo read sections 22 are configured to be able to reproduce servo signals by reading the magnetic field caused by the servo patterns 7 recorded on the servo bands s of the magnetic tape MT using an MR element (MR: Magneto Resistive effect) or the like.

[0077] Examples of MR elements that can be used include anisotropic magnetoresistive effect elements (AMR: Anisotropic Magneto Resistive effect), giant magnetoresistive effect elements (GMR: Giant Magneto Resistive effect), and tunnel magnetoresistive effect elements (TMR: Tunnel Magneto Resistive effect).

[0078] The data write / read sections 23 are arranged at equal intervals along the longitudinal direction (Y'-axis direction) of the data write head 20. Furthermore, the data write / read sections 23 are arranged at positions sandwiched between two servo read sections 22. The number of data write / read sections 23 is, for example, about 20 to 40, but there are no particular limitations on this number.

[0079] The data write / read section 23 includes a data write section 24 and a data read section 25. The data write section 24 is configured to be able to record data on the data band d of the magnetic tape MT by using a magnetic field generated from the magnetic gap. The data read section 25 is configured to be able to reproduce data signals by reading the magnetic field caused by the data recorded on the data band d of the magnetic tape MT using an MR element or the like. The MR element may be an anisotropic magnetoresistance element (AMR), a giant magnetoresistance element (GMR), a tunnel magnetoresistance element (TMR), or the like.

[0080] In the first data write head 20a, the data write section 24 is located to the left of the data read section 25 (upstream when the magnetic tape MT flows in the forward direction), while in the second data write head 20b, the data write section 24 is located to the right of the data read section 25 (upstream when the magnetic tape MT flows in the reverse direction).

[0081] The data read unit 25 is capable of reproducing the data signal immediately after the data write unit 24 paired with the data read unit 25 has written the data onto the magnetic tape MT. Alternatively, data written by the data write unit 24 of one of the first data write head 20a and the second data write head 20b may be reproduced by the data read unit 25 of the other data write head 20.

[0082] The magnetic tape MT travels back and forth many times, with its running direction changed between forward and reverse, while data is recorded on the recording track 6 by the first data write head 20a and the second data write head 20b.

[0083] The angle adjustment unit 17 is capable of holding the first data write head 20a and the second data write head 20b rotatably around an axis (Z' axis) in the vertical direction, and is also capable of individually rotating the first data write head 20a and the second data write head 20b around the axis in the vertical direction.

[0084] The angle adjustment unit 17 adjusts the angles of the first data write head 20a and the second data write head 20b so that the longitudinal directions of the first data write head 20a and the second data write head 20b are inclined at an azimuth angle θ with respect to the width direction of the magnetic tape MT.

[0085] Here, the positions of the servo read section 22 and data write / read section 23 of the first data write head 20a in the Y-axis direction (width direction of the magnetic tape MT) are the same as the positions of the servo read section 22 and data write / read section 23 of the second data write head 20b in the Y-axis direction. This positional relationship does not change even if the first data write head 20 and the second data write head 20 rotate around the Z-axis.

[0086] In other words, the angle adjustment unit 17 is capable of individually rotating the first data write head 20a and the second data write head 20b so that the positions of the servo read section 22 and data write / read section 23 of the first data write head 20 in the Y-axis direction (width direction of the magnetic tape MT) are the same as the positions of the servo read section 22 and data write / read section 23 of the second data write head 20b in the Y-axis direction.

[0087] In this embodiment, a reference angle Refθ is set as a reference for the azimuth angle θ of the data write head 20, and an angle range expressed as the reference angle Refθ±x° is set for the azimuth angle θ of the data write head 20. The reference angle Refθ is set to 8° or more, and the value of x in Refθ±x° is typically set to 0.7° or less.

[0088] 9 shows an example in which the reference angle Refθ is set in a clockwise direction (as viewed from the bottom side of the magnetic tape MT) relative to the width direction of the magnetic tape MT. On the other hand, the reference angle Refθ may be set in a counterclockwise direction (as viewed from the bottom side of the magnetic tape MT) relative to the width direction of the magnetic tape MT.

[0089] As described above, in this embodiment, the longitudinal direction of the data write head 20 in the data recording / reproducing device 100 is inclined by the azimuth angle θ with respect to the width direction of the magnetic tape MT, and the azimuth angle θ is adjusted, thereby making it possible to accommodate variations in the width of the magnetic tape MT.

[0090] In this embodiment, the azimuth angle θ of the data write head 20 in the data recording / reproducing device 100 is adjusted within the range of the reference angle Refθ±x°. In this case, by setting the value of x to 0.7° or less, it is possible to accommodate a magnetic tape MT with a small reproduction track width W (for example, 0.5 μm or less) while minimizing the azimuth loss L θ In this case, by setting the reference angle Refθ to 8° or more, the correction amount can be increased (for example, 10 μm or more).

[0091] [Regarding the effect of the connection step between the magnetic tape and the leader tape on the PES] In the tape cartridge 50 of this embodiment, when information is recorded on the magnetic tape MT using the data recording and reproducing device 100 shown in Figures 8 and 9, a position error signal (PES) is generated by reading the servo pattern 7 (see Figure 5) recorded in the servo band s, and the data write head 20 is appropriately positioned with respect to the recording track 6.

[0092] However, as the density of the recording tracks 6 increases (the track pitch and track width become narrower), even a slight change in the shape of the magnetic tape MT can have a significant effect on the PES. For example, Fig. 10 shows the results of an experiment showing the change in the σPES value, which is the standard deviation of the PES value, when information is recorded on the magnetic tape MT in the Rvs direction (the A2 direction in Fig. 8).

[0093] 10, the values ​​on the horizontal axis represent the region numbers of the magnetic tape MT (20 m per region), with number 1 corresponding to the BOT of the magnetic tape MT. Also, in Fig. 10, the vertical axis represents the σPES value (unit: nm). Focusing on the section with region numbers 1 to 5 in the figure, the σPES value tends to increase (deteriorate) near the BOT of the magnetic tape MT.

[0094] The inventors focused on the step at the joint between the magnetic tape MT and the leader tape LT as a factor in the deterioration of the σPES value near the BOT. As described above, the average thickness of the leader tape LT is greater than that of the magnetic tape MT, and furthermore, the thickness of the splice tape ST that joins them is equal to or greater than the average thickness of the leader tape LT. For this reason, as shown in FIG. 3 , the step (A) at the joint between the magnetic tape MT and the leader tape LT is larger than the thickness (E) of the magnetic tape MT. The step (A) is calculated as the difference between the thickness (E) of the magnetic tape MT and the sum (B) of the thickness (C) of the leader tape LT and the thickness (D) of the splice tape ST (A = B - E, B = C + D).

[0095] When the step (A) becomes large compared to the thickness (E) of the magnetic tape MT, the pressure applied when the magnetic tape MT is wound around the take-up reel 12 of the data recording and reproducing device 100 causes the area of ​​the magnetic tape MT near the BOT to be pressed against the step, deforming it (root compression), and it is presumed that this deformed area manifests itself as a deterioration in the PES value in areas 1 to 5 of the magnetic tape MT.

[0096] Based on the above considerations, the inventors prepared multiple magnetic recording medium samples with varying thicknesses of the leader tape LT and splice tape ST, and wound each of these around a tape reel 54 to assemble a tape cartridge 50. These tape cartridges 50 were then loaded into the data recording and reproducing device 100, and the average PES values ​​in regions 1 to 5 of the magnetic tape MT were calculated while the magnetic tape MT was running in the Rvs direction. The results are shown in Table 1.

[0097]

[0098] (Experimental Example 1) A magnetic recording medium sample was produced using a magnetic tape MT having a thickness of 5.2 μm, a leader tape LT having a thickness of 8.9 μm, and a splice tape ST having a thickness of 17 μm. The step (A) at the joint between the magnetic tape MT and the leader tape LT in this sample was 20.7 μm, and the ratio of the step (A) to the thickness (E) of the magnetic tape MT was 4.0. The average PES value of regions 1 to 5 of the magnetic tape MT was measured using this magnetic recording medium sample, and was found to be 24.2 nm.

[0099] (Experimental Example 2) A magnetic recording medium sample was produced using a magnetic tape MT having a thickness of 5.2 μm, a leader tape LT having a thickness of 8.9 μm, and a splice tape ST having a thickness of 22 μm. The step (A) at the joint between the magnetic tape MT and the leader tape LT in this sample was 25.7 μm, and the ratio of the step (A) to the thickness (E) of the magnetic tape MT was 4.9. The average PES value of regions 1 to 5 of the magnetic tape MT was measured using this magnetic recording medium sample, and was found to be 25.6 nm.

[0100] (Experimental Example 3) A magnetic recording medium sample was produced using a magnetic tape MT having a thickness of 5.2 μm, a leader tape LT having a thickness of 17 μm, and a splice tape ST having a thickness of 22 μm. The step (A) at the joint between the magnetic tape MT and the leader tape LT in this sample was 33.8 μm, and the ratio of the step (A) to the thickness (E) of the magnetic tape MT was 6.5. The average PES value of regions 1 to 5 of the magnetic tape MT was measured using this magnetic recording medium sample, and was found to be 27.2 nm.

[0101] (Experimental Example 4) A magnetic recording medium sample was produced using a magnetic tape MT having a thickness of 5.2 μm, a leader tape LT having a thickness of 17 μm, and a splice tape ST having a thickness of 17 μm. The step (A) at the joint between the magnetic tape MT and the leader tape LT in this sample was 28.8 μm, and the ratio of the step (A) to the thickness (E) of the magnetic tape MT was 5.5. The average PES value of regions 1 to 5 of the magnetic tape MT was measured using this magnetic recording medium sample, and was found to be 26.0 nm.

[0102] 11 is a graph plotting the step-to-magnetic tape ratio (A / E) and the RvsPES BOT 100m average value (hereinafter also referred to as the PES average value) from Table 1. As shown in the figure, there is a strong correlation between the step-to-magnetic tape ratio (A / E) and the PES average value, and the smaller the step-to-magnetic tape ratio (A / E), the smaller the PES average value tends to be. In other words, in order to keep the PES average value low, it is necessary to reduce the step-to-magnetic tape ratio (A / E).

[0103] For example, by using the step-to-magnetic tape ratio (A / E) as an evaluation index and setting it to 5 or less, the average PES value can be kept below 26 nm (see Experimental Examples 1 and 2). In particular, by setting the evaluation index to 4 or less, the average PES value can be kept to 25 nm or less (Experimental Example 1). The above evaluation index is merely an example, and the evaluation index may be set to 5.5 or less, in which case the average PES value can be kept to 26 nm or less (see Experimental Examples 1, 2, and 4).

[0104] It has been confirmed that the effect of the step-to-magnetic tape ratio (A / E) on the PES value is more pronounced in a data recording / reproducing device 100 in which the data write head 20 is inclined at a predetermined azimuth angle θ with respect to the tape width direction, as shown in Fig. 9. In other words, in a magnetic tape having a servo pattern symmetrical with respect to the tape width direction, as shown in Fig. 6A, the step-to-magnetic tape ratio (A / E) does not have a significant effect on the PES value, and therefore no attention has been paid to the step-to-magnetic tape ratio (A / E) in order to improve the PES value.

[0105] On the other hand, in order to accommodate future narrowing of data tracks, it has been confirmed that if the servo pattern 7 is made asymmetric with respect to the tape width direction as shown in FIG. 6B and a data recording / reproducing device 100 is adopted in which the data write head 20 is tilted at a predetermined azimuth angle θ, the effect of the step-to-magnetic tape ratio (A / E) on the PES value will become more pronounced. In particular, as the magnetic tape MT becomes thinner, the tape length increases and the winding pressure of the magnetic tape MT on the take-up reel 12 also increases, so it is expected that the effect of the size of the step (A) on the average PES will become even greater in the future. Based on this knowledge, for magnetic tapes MT having the above-mentioned servo pattern shape asymmetric with respect to the tape width direction, the average PES is preferably 26 nm or less, and more preferably 25 nm or less.

[0106] To obtain the above effects, the average thickness of the leader tape LT is preferably 5.0 μm or more and 10.0 μm or less. If the average thickness of the leader tape LT is less than 5.0 μm, the necessary strength cannot be ensured, and there is a risk of breakage at the fixing portion of the leader pin 68, etc. Furthermore, if the average thickness of the leader tape LT exceeds 10 μm, the effect of suppressing the average PES value becomes smaller, as in Experimental Examples 3 and 4.

[0107] As described above, according to this embodiment, when the difference between the joint thickness (B=(C+D)), which is the sum of the thickness (C) of the leader tape LT and the thickness (D) of the splice tape ST, and the thickness (E) of the magnetic tape MT is defined as the joint step (A=(B-E)), by setting the ratio (A / E) of the joint step (A) to the thickness (E) of the magnetic tape MT to 5 or less, it is possible to keep the average PES low and ensure highly accurate and reliable recording characteristics with few recording errors in a magnetic recording medium 1 having a servo pattern that is asymmetric in the tape width direction, such as servo pattern 7.

[0108] Second Embodiment Next, a second embodiment of the present technology will be described. In this description, the basic concept of the second embodiment will be described.

[0109] [Basic Concept of the Second Embodiment] As described above, in the first embodiment, a step exists at the joint between the leader tape LT and the magnetic tape MT. When the magnetic recording medium 1 is wound onto the take-up reel 12 of the data recording and reproducing device 100 and formed into a roll, this step forms a protrusion, which causes deformation of the magnetic recording medium 1 at the portion corresponding to this step, which causes a deterioration in the PES value at the beginning (BOT) side of the magnetic tape MT.

[0110] In order to reduce the adverse effects of the step at the joint between the leader tape LT and the magnetic tape MT, the first embodiment described above adopts a method of making this step as small as possible (for example, a step-to-magnetic tape ratio (A / E) of 5 or less).

[0111] In contrast to this, the second embodiment employs a technique in which the leader tape LT is eliminated, and the joint portion is also eliminated, thereby eliminating the step itself caused by the joint portion. By eliminating the joint portion and the step itself in this way, when the magnetic recording medium 1 is wound onto the take-up reel 12 and formed into a roll, there is no protrusion caused by the step, and therefore deformation of the magnetic recording medium 1 at the step portion is also eliminated. Therefore, it is believed that the root cause of the deterioration of the PES value at the starting end (BOT) side of the magnetic tape MT can be eliminated.

[0112] In the case of the technique according to the second embodiment, since there is no leader tape LT, one end (starting end) of the magnetic tape MT in the longitudinal direction (X-axis direction) is fixed to the leader pin 68 (note that in the first embodiment described above, the starting end of the leader tape LT is fixed to the leader pin 68; see FIG. 2).

[0113] On the other hand, the average thickness of the magnetic tape MT is relatively thin, for example, 5.3 μm or less. Therefore, if no countermeasures are taken and one end (starting end) of the magnetic tape MT in the longitudinal direction (X-axis direction) is directly fixed to the leader pin 68, damage will occur at this portion, and in the worst case, the magnetic tape MT may break.

[0114] Therefore, in the second embodiment, a reinforcing portion 91 for reinforcing the magnetic tape MT is provided at one end (starting end) in the longitudinal direction of the magnetic tape MT, at a position where the magnetic tape MT is fixed to the leader pin 68. This makes it possible to appropriately prevent damage, breakage, etc. of the magnetic tape MT.

[0115] The above is the basic concept of the second embodiment.

[0116] [Configuration of Magnetic Recording Medium] Next, the configuration of the magnetic recording medium 90 according to the second embodiment will be described in detail.

[0117] Fig. 12 is a plan view of a magnetic recording medium 90 according to a second embodiment of the present disclosure, as viewed from its thickness direction. Fig. 13 is a partially enlarged perspective view showing a connecting portion between the leader pin 68 and the magnetic tape MT in the tape cartridge 50.

[0118] Fig. 14 is an enlarged perspective view showing the state when the magnetic recording medium is fixed to the leader pin 68 by the clamper 72. Fig. 15 is a cross-sectional view taken along line A-A in Fig. 13, and is a side cross-sectional view showing the connecting portion between the leader pin 68 and the magnetic recording medium 90.

[0119] As shown in these figures, the magnetic recording medium 90 according to the second embodiment comprises a magnetic tape MT and a reinforcing portion 91 provided at one longitudinal end (starting end) of the magnetic tape MT at a position where it is fixed to the leader pin 68.

[0120] The magnetic tape MT in the second embodiment has a configuration basically similar to that of the magnetic tape MT in the first embodiment, except that the length (in the X-axis direction) of the magnetic tape MT in the second embodiment is set to be longer than that of the magnetic tape MT in the first embodiment by a length L1 corresponding to the leader tape LT.

[0121] The magnetic tape MT of the second embodiment includes a leader section MT1 at the beginning and a recording section MT2 at the end. The leader section MT1 records, for example, information to be recorded on the leader tape LT (such as an identification signal that identifies the section as corresponding to the leader tape LT). The recording section MT2 records servo patterns 7 and data. The length L1 (X-axis direction) of the leader section MT1 is, for example, approximately 900 mm±30 mm, and the length L2 of the recording section MT2 is, for example, approximately 1034 m or more and 1037 m or less.

[0122] In LTO-9 and earlier standards, the length of the leader tape LT is standardized at 900 mm ± 30 mm, and the length of the magnetic tape MT is standardized at 1034 m or more and 1037 m or less. Correspondingly, in the second embodiment, the length L1 of the leader section MT1 is 900 mm ± 30 mm, and the length of the recording section MT2 is 1034 m or more and 1037 m or less.

[0123] In this example, the reinforcing portion 91 is configured as a thin tape (reinforcing tape) extending in the thickness direction (Z-axis direction) and is laminated on one side of the magnetic tape MT via an adhesive layer. The reinforcing portion 91 is typically provided on the upper surface side (magnetic layer 4 side) of the magnetic tape MT, but may also be provided on the lower surface side (back layer 5 side) of the magnetic tape MT.

[0124] However, when the magnetic recording medium 90 is sandwiched between the leader pin 68 and the clamper 72, pressure is more likely to be applied to the magnetic recording medium 90 on the clamper 72 side than on the leader pin 68 side. Therefore, it is particularly effective to provide a reinforcing portion 91 on the upper surface of the magnetic tape MT, which faces the clamper 72. Note that the reinforcing portion 91 may be provided on both the upper and lower surfaces of the magnetic tape MT.

[0125] Examples of materials that can be used for the reinforcing portion 91 include various resin materials such as polyester, polyethylene, aramid, polyimide, fluorine-based resin, and polyether ether ketone, various metal materials such as aluminum, and fiber materials such as acetate fiber. Note that the same tape as the splice tape ST described above may also be used for the reinforcing portion 91.

[0126] If the thickness (Z-axis direction) of the reinforcing portion 91 is too thin, it will not be able to adequately reinforce the magnetic tape MT. Therefore, the thickness of the reinforcing portion 91 is, for example, 5 μm or more. On the other hand, if the thickness of the reinforcing portion 91 is too thick, it will not be possible to properly clamp the portion of the magnetic tape MT where the reinforcing portion 91 is provided by the clamper 72. Furthermore, the thickness of the reinforcing portion 91 is sufficient as long as it can adequately reinforce the magnetic tape MT, so there is no need to make it unnecessarily thick. Therefore, the thickness of the reinforcing portion 91 is typically 30 μm or less.

[0127] The width (Y-axis direction) of the reinforcement portion 91 is the same (or approximately the same) as the width of the magnetic tape MT (1 / 2 inch). The length (X-axis direction) of the reinforcement portion 91 is, for example, 3.1 mm or more and 8.4 mm or less. Details regarding the length of the reinforcement portion 91 will be described later. The center position of the reinforcement portion 91 in the width direction (Y-axis direction) coincides with the center position of the magnetic tape MT in the width direction, and the position of the starting end of the reinforcement portion 91 coincides with the position of the starting end of the magnetic tape MT.

[0128] The hardness (Young's modulus) (longitudinal and transverse directions) of the reinforcing portion 91 is set to, for example, the same hardness as that of the magnetic tape MT (for example, about 80% to 120% of the hardness (Young's modulus) of the magnetic tape).

[0129] The leader pin 68 has a columnar pin portion 68a that is long in one direction (the Y-axis direction) and a pair of head portions 68b provided at both ends of the pin portion 68a in the longitudinal direction (the Y-axis direction). The leader pin 68 also has a pair of stopper portions 68c provided at both ends of the pin portion 68a at positions closer to the center in the longitudinal direction than the pair of head portions 68b.

[0130] The pin portion 68a is configured, for example, in a cylindrical shape, but may be in another shape such as a polygonal prism, and the shape is not particularly limited. The pair of head portions 68b are configured in a cylindrical shape (which may be a polygonal prism, etc., and the shape is not particularly limited) that is short in the longitudinal direction (Y-axis direction) and has a larger outer diameter than the pin portion 68a. The pair of stopper portions 68c are configured in a flange shape (which may be a polygonal prism, etc., and the shape is not particularly limited) that is short in the longitudinal direction and has a larger outer diameter than the pin portion 68a.

[0131] The pin portion 68a, the pair of head portions 68b, and the pair of stopper portions 68c have their central axes positioned so that they coincide with each other in the longitudinal direction (Y-axis direction).

[0132] The pair of stopper portions 68c are capable of supporting both ends in the width direction (Y-axis direction) of the magnetic recording medium 90 (where the reinforcing portions 91 are provided), thereby making it possible to prevent misalignment in the width direction between the leader pin 68 and the magnetic recording medium 90. The distance (Y-axis direction) between one stopper portion 68c and the other stopper portion 68c is set to a size slightly larger than the width (½ inch) of the magnetic recording medium 90.

[0133] The clamper 72 is capable of fixing the leader pin 68 to the starting end side of the magnetic recording medium 90 by clamping the magnetic recording medium 90 (the portion where the reinforcing portion 91 is provided) between the clamper 72 and the leader pin 68.

[0134] The clamper 72 is configured in a cylindrical shape (it may be a polygonal cylindrical shape or the like, and the shape is not particularly limited) that is long in the longitudinal direction (X-axis direction), and is formed so that a portion of the circumferential direction of the cylindrical body is cut out along the longitudinal direction (X-axis direction). The clamper 72 has a generally C-shaped shape when viewed from the longitudinal direction (X-axis direction).

[0135] The clamper 72 has an inner peripheral surface 72a that sandwiches the starting end side of the magnetic recording medium 90 between itself and the outer peripheral surface 68d of the pin portion 68a of the leader pin 68. The diameter of the inner peripheral surface 72a of the clamper 72 is slightly larger than the diameter of the outer peripheral surface 68d of the pin portion 68a of the leader pin 68 (when the magnetic recording medium 90 is sandwiched between itself and the leader pin 68).

[0136] The magnetic recording medium 90 (where the reinforcing portion 91 is provided) is sandwiched between the outer surface 68d of the pin portion 68a of the leader pin 68 and the inner surface 72a of the clamper 72, thereby fixing the leader pin 68 to the starting end side of the magnetic recording medium 90.

[0137] Here, the portion of the reinforcing portion 91 of the magnetic recording medium 90 that is clamped and sandwiched between the outer peripheral surface 68d of the leader pin 68 and the inner peripheral surface 72a of the clamper 72 is referred to as the intervening portion 91a. Furthermore, the portion of the reinforcing portion 91 of the magnetic recording medium 90 that is closer to the end (outside) of the reinforcing portion 91a in the longitudinal direction (X-axis direction) than the intervening portion 91a and that is not clamped by the clamper 72 is referred to as the first marginal portion 91b. Furthermore, the portion of the reinforcing portion 91 of the magnetic recording medium 90 that is closer to the center (inside) of the reinforcing portion 91a in the longitudinal direction (X-axis direction) than the intervening portion 91a and that is not clamped by the clamper 72 is referred to as the second marginal portion 91c. In other words, the reinforcing portion 91 includes the intervening portion 91a, the first marginal portion 91b, and the second marginal portion 91c.

[0138] The length of the intervening portion 91a (in the X-axis direction) is approximately equal to the radial length of the inner peripheral surface 72a of the clamper 72 (i.e., the length of the intervening portion 91a is related to the length of the inner peripheral surface 72a of the clamper 72), and the length of this intervening portion 91a is typically about 2.1 mm or more and 3.4 mm or less. If the length of the first marginal portion 91b is too short, it may not be possible to properly clamp the reinforcing portion 91, and if it is too long, it may become a hindrance. For this reason, the length of the first marginal portion 91b is typically 0.5 mm or more and 2.5 mm or less.

[0139] Furthermore, if the length (X-axis direction) of the second margin 91c is too short, it may not be possible to properly clamp the reinforcing portion 91. Therefore, the second margin 91c is typically set to 0.5 mm or more. On the other hand, if the length (X-axis direction) of the second margin 91c is too long, the problems described below may occur.

[0140] FIG. 16 is a diagram for explaining the upper limit of the length of the second margin 91c, showing the state when the magnetic recording medium 90 is being taken up by the take-up roller 12. In FIG.

[0141] 16, the take-up roller 12 has a roller portion 12a and a pin holding portion 12b provided on the roller portion 12a. The roller portion 12a is formed, for example, in a cylindrical shape and is configured so that it can take up the magnetic recording medium 90 by rotating. The pin holding portion 12b is configured so that it can detachably hold a leader pin 68. This pin holding portion 12b is provided at a distance D1 radially inward from the outer circumferential surface of the roller portion 12a.

[0142] If the length (X-axis direction) of the second margin 91c exceeds the distance D1, a step between the reinforcing portion 91 and the magnetic tape MT may appear as a protrusion when the magnetic recording medium 90 is wound around the winding roller 12 into a roll. In this case, deformation of the magnetic recording medium 90 occurs at this step, which may cause a deterioration in the PES value at the starting end (BOT) of the magnetic tape MT.

[0143] Therefore, the length (in the X-axis direction) of the second margin 91c is typically equal to or less than the distance D1 (i.e., the length of the second margin 91c is related to the distance D1). Since the distance D1 is, for example, about 2.5 mm, the length of the second margin 91c is typically equal to or less than 2.5 mm.

[0144] Here, the overall length (X-axis direction) of the reinforcing portion 91 will be described. First, the length of the reinforcing portion 91 must be at least a length corresponding to the length of the interposed portion 91a. The length of this interposed portion 91a is approximately equal to the length of the inner peripheral surface 72a of the clamper 72, so the length of the reinforcing portion 91 must be at least a length corresponding to the length of the inner peripheral surface 72a of the clamper 72.

[0145] On the other hand, it is not necessarily possible to fix the lead pin 68 and the clamper 72 at the same position for all magnetic recording media 90. Furthermore, the reinforcing portion 91 may be slightly misaligned in the circumferential direction of the lead pin 68 and the clamper 72 when sandwiched between them. Therefore, in the second embodiment, the length of the reinforcing portion 91 is made longer than the length of the intervening portion 91a (the length of the inner peripheral surface of the clamper) to allow for some margin. For this reason, in the second embodiment, the reinforcing portion 91 is provided with a first margin 91b and a second margin 91b in addition to the intervening portion 91a.

[0146] As described above, the lower limit of the intervening portion 91a is 2.1 mm, the lower limit of the first margin portion 91b is 0.5 mm, and the lower limit of the second margin portion 91c is 0.5 mm. Therefore, the length of the reinforcing portion 91 is typically 3.1 mm (= 2.1 mm + 0.5 mm + 0.5 mm) or more.

[0147] As described above, the upper limit of the intervening portion 91a is 3.4 mm, the upper limit of the first margin portion 91b is 2.5 mm, and the upper limit of the second margin portion 91c is 2.5 mm. Therefore, the length of the reinforcing portion 91 is typically 8.4 mm (= 3.4 mm + 2.5 mm + 2.5 mm) or less.

[0148] [Operation, etc.] As explained above, the second embodiment employs a technique of eliminating the leader tape LT and the joint, thereby eliminating the step itself caused by the joint. By eliminating the joint and the step itself in this way, when the magnetic recording medium 90 is wound onto the take-up reel 12 and formed into a roll, there is no protrusion caused by the step, and deformation of the magnetic recording medium 90 at the step is also eliminated. Therefore, it is possible to eliminate the root cause of the deterioration of the PES value at the starting end (BOT) side of the magnetic tape MT.

[0149] On the other hand, in the case of the technique according to the second embodiment, since there is no leader tape LT, one end side (starting end side) of the magnetic tape MT in the longitudinal direction (X-axis direction) is fixed to the leader pin 68.

[0150] Fig. 17 is an enlarged perspective view showing the state when the magnetic recording medium 92 according to the comparative example is fixed to the leader pin 68 by the clamper 72. Fig. 18 is a side cross-sectional view showing the connecting portion between the magnetic recording medium 92 according to the comparative example and the leader pin 68.

[0151] Unlike the magnetic recording medium 90 according to the second embodiment, the magnetic recording medium 92 according to the comparative example does not have a reinforcing portion 91. As shown in Figures 17 and 18, it is assumed that one end (starting end) of the magnetic tape MT in the longitudinal direction (X-axis direction) is directly fixed to the leader pin 68. In this case, since the magnetic tape MT is relatively thin (5.3 µm or less), damage may occur at the location where the leader pin 68 is fixed, and in the worst case scenario, the magnetic tape MT may break.

[0152] Therefore, in the second embodiment, a reinforcing portion 91 for reinforcing the magnetic tape MT is provided at one end (starting end) in the longitudinal direction of the magnetic tape MT, at a position where the magnetic tape MT is fixed to the leader pin 68. This makes it possible to appropriately prevent damage, breakage, etc. of the magnetic tape MT.

[0153] In the second embodiment, the reinforcing portion 91 has an intervening portion 91 a, a first margin portion 91 b, and a second margin portion 91 c. By providing the first margin portion 91 b and the second margin portion 91 c in addition to the intervening portion 91 a, the portion of the magnetic tape MT where the reinforcing portion 91 is provided can be appropriately clamped by the clamper 72 to fix the leader pin 68.

[0154] In the second embodiment, the length of the interposed portion 91a (in the X-axis direction) is set to 2.1 mm or more and 3.4 mm or less (the circumferential length of the inner circumferential surface 72a of the clamper 72). This allows the reinforcing portion 91 to have a minimum length.

[0155] In the second embodiment, the length (in the X-axis direction) of the first margin 91b is set to 0.5 mm or more and 2.5 mm or less, which allows the clamper 72 to properly clamp the magnetic tape MT at the location where the reinforcing portion 91 is provided, and also prevents the first margin 91b from getting in the way.

[0156] In the second embodiment, the length (in the X-axis direction) of the second margin 91c is set to 0.5 mm or more, so that the portion of the magnetic tape MT where the reinforcing portion 91 is provided can be appropriately clamped by the clamper 72.

[0157] In the second embodiment, the length (X-axis direction) of the second margin portion 91c is related to the distance D1 (see FIG. 16 ), and is set to be equal to or less than the distance D1. Typically, the length (X-axis direction) of the second margin portion 91c is set to be 2.5 mm or less.

[0158] This prevents a step between the reinforcing portion 91 and the magnetic tape MT from appearing as a protrusion when the magnetic recording medium 90 is wound around the winding roller 12 into a roll, which can cause deformation of the magnetic recording medium 90 at the step, thereby preventing the PES value from deteriorating at the leading end of the magnetic tape MT.

[0159] In the second embodiment, the length (X-axis direction) of the reinforcing portion 91 is set to be 3.1 mm or more and 8.4 mm or less, thereby making it possible to set the length of the reinforcing portion 91 to an appropriate length.

[0160] In the second embodiment, the thickness (Z-axis direction) of the reinforcing portion 91 is set to 5 μm or more and 30 μm or less, so that the reinforcing portion 91 can appropriately reinforce the magnetic tape MT.

[0161] Next, the operation of the second embodiment will be described from the perspective of the step-to-magnetic tape ratio (A / E) described in the first embodiment. Table 2 shows the relationship between the step-to-magnetic tape ratio (A / E) in Experimental Examples 1 to 5 and the above (A) to (E) (see also FIG. 3).

[0162]

[0163] In Table 2, Experimental Examples 1 to 4 are the same as Experimental Examples 1 to 4 in Table 1 of the first embodiment described above. Note that in Table 2, Examples 1 to 4 correspond to the first embodiment, and Experimental Example 5 corresponds to the second embodiment.

[0164] In Experimental Example 5, which corresponds to the second embodiment, there is no joint, so the areas corresponding to the joint step (A) and joint thickness (B) are left blank. Furthermore, in Experimental Example 5, there is no leader tape LT or splice tape LT, so the areas corresponding to the leader tape LT thickness (C) and the splice tape ST thickness (D) are also left blank. Note that Experimental Example 5 assumes a magnetic tape MT thickness (E) of 5.2 μm, as in Experimental Examples 1 to 4.

[0165] 19 is a graph plotting the relationship between the step-to-magnetic tape ratio (A / E) and the RvsPES BOT 100m average value (PES average value) for Experimental Examples 1 to 4 in Table 2. Using these four plots for Experimental Examples 1 to 4, the slope and intercept of the approximate line were determined by the least squares method (y=1.1149x+19.894).

[0166] Here, in Experimental Example 5 corresponding to the second embodiment, there is no step due to the joint portion. Therefore, the average PES value when the step-to-magnetic tape ratio (A / E) value in the approximate straight line is set to 0 (because the step (A) = 0 in Experimental Example 5) can be regarded as the average PES value in Experimental Example 5. Therefore, the average PES value in Experimental Example 5 is estimated to be approximately 20 nm (≈19.894).

[0167] From this explanation, it can be seen that the PES value can be improved in the second embodiment. Note that the average PES value is lower in Experimental Example 5 according to the second embodiment than in Experimental Examples 1 to 4 corresponding to the first embodiment described above. Therefore, using the technique according to the second embodiment in the present technology is particularly effective from the viewpoint of improving the PES value.

[0168] <Various Modifications of Second Embodiment> Next, various modifications of the second embodiment will be described.

[0169] [First Modification] FIG. 20 is a side cross-sectional view showing a connecting portion between a magnetic recording medium 93 and a leader pin 68 according to a first modification.

[0170] In the magnetic recording medium 93 according to the first modification, the reinforcing portion 91 is configured by a folded portion 94 of the magnetic tape. The folded portion 94 is formed by folding the starting end of the magnetic tape MT back onto the upper surface side (magnetic layer side) of the magnetic tape MT, with a line along the width direction (Y-axis direction) as a valley fold line. Alternatively, the folded portion 94 may be formed by folding the starting end of the magnetic tape MT back onto the lower surface side (back layer side) of the magnetic tape MT, with a line along the width direction (Y-axis direction) as a mountain fold line.

[0171] [Second Modification] FIG. 21 is a side cross-sectional view showing a connecting portion between a magnetic recording medium 95 and a leader pin 68 according to a second modification.

[0172] In the second embodiment described above, the reinforcing portion 91 is bonded to the magnetic tape MT via an adhesive layer. On the other hand, in the second modified example, the reinforcing portion 96 is not bonded to the magnetic tape MT via an adhesive layer, but is a separate body separated from the magnetic tape MT. The reinforcing portion 96 may be disposed on the upper surface (magnetic layer side) of the magnetic tape MT, or on the lower surface (back layer side) of the magnetic tape MT (or on both the upper and lower surfaces).

[0173] <Details of Magnetic Tape> Next, the magnetic tape MT will be described in detail.

[0174] The magnetic tape MT has a long tape shape and runs in the longitudinal direction when recording / reproducing data and servo patterns 7. The surface of the magnetic layer 4 is the surface on which the data write head 20 and servo write head 40 run. The magnetic tape MT is preferably used in a recording / reproducing device equipped with a ring-type head as the recording head. The magnetic tape MT is preferably used in a recording / reproducing device configured to be able to record data with a data track width of 800 nm or less or 600 nm or less.

[0175] The length of the magnetic recording medium 1 is, for example, 1000 m or more. When the tape length is 1000 m or more, the number of turns of tape when wound around the reel hub 55 (hub diameter 44 mm) of the tape reel 54 exceeds 4700.

[0176] (Substrate 2) The substrate 2 is a non-magnetic support that supports the underlayer 3 and the magnetic layer 4. The substrate 2 has the shape of a long film. The upper limit of the average thickness of the substrate 2 is preferably 4.4 μm or less, more preferably 4.2 μm or less, even more preferably 4.0 μm or less, and most preferably 3.6 μm or less. If the upper limit of the average thickness of the substrate 2 is 4.4 μm or less, the recording capacity that can be recorded in one data cartridge 10 can be increased compared to that of a typical magnetic tape MT. The lower limit of the average thickness of the substrate 2 is preferably 3 μm or more, more preferably 3.2 μm or more. If the lower limit of the average thickness of the substrate 2 is 3 μm or more, a decrease in the strength of the substrate 2 can be suppressed.

[0177] The average thickness of the substrate 2 is determined as follows. First, a 1 / 2-inch wide magnetic tape MT is prepared and cut into a length of 250 mm to prepare a sample. Next, the layers other than the substrate 2 of the sample (i.e., the underlayer 3, magnetic layer 4, and back layer 5) 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 2) is measured at five or more positions, and the measured values ​​are simply averaged (arithmetic mean) to calculate the average thickness of the substrate 2. Note that the measurement positions are selected randomly from the sample.

[0178] The base material 2 preferably contains polyester. The base material 2 has a Young's modulus in the longitudinal direction of, for example, 2.5 GPa or more and 10 GPa or less, preferably 2.5 GPa or more and 7.8 GPa or less, and more preferably 3.0 GPa or more and 7.2 GPa or less.

[0179] The polyester includes, for example, at least one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polycyclohexylene dimethylene terephthalate (PCT), polyethylene-p-oxybenzoate (PEB), and polyethylene bisphenoxycarboxylate. When the substrate 2 includes two or more types of polyester, the two or more types of polyester may be mixed, copolymerized, or laminated. At least one of the terminals and side chains of the polyester may be modified.

[0180] The inclusion of polyester in the substrate 2 can be confirmed, for example, as follows. First, similar to the method for measuring the average thickness of the substrate 2, a magnetic tape MT is prepared and cut to a length of 250 mm to prepare a sample, and then the layers of the sample other than the substrate 2 are removed. Next, an IR spectrum of the sample (substrate 2) is obtained by infrared absorption spectrometry (IR). Based on this IR spectrum, it can be confirmed that the substrate 2 contains polyester.

[0181] The substrate 2 may be made of, in addition to polyester, for example, polyamide, polyetheretherketone, polyimide, polyamideimide, polyetheretherketone (PEEK), polyolefins, cellulose derivatives, vinyl resins, or other polymer resins. The polyamide may be an aromatic polyamide (aramid). The polyimide may be an aromatic polyimide. The polyamideimide may be an aromatic polyamideimide.

[0182] The substrate 2 may contain at least one of polyamide, polyether ether ketone, polyimide, polyamideimide, and polyether ether ketone (PEEK), or may have a resin such as polyamide, polyimide, polyamideimide, polyolefins, cellulose derivatives, or vinyl resin as its main component.

[0183] When the substrate 2 contains a polymer resin other than polyester, it is preferable that the substrate 2 contains polyester as a main component. Here, the main component refers to the component with the largest content (mass ratio) among the polymer resins contained in the substrate 2. When the substrate 2 contains a polymer resin other than polyester, the polyester and the polymer resin other than polyester may be mixed or copolymerized.

[0184] The substrate 2 may be biaxially stretched in the longitudinal direction and the width direction. The polymer resin contained in the substrate 2 is preferably oriented in a direction oblique to the width direction of the substrate 2.

[0185] (Magnetic Layer 4) The magnetic layer 4 is a recording layer for recording signals using a magnetization pattern. The magnetic layer 4 may be a perpendicular recording type recording layer or a longitudinal recording type recording layer. The magnetic layer 4 contains, for example, a magnetic powder, a binder, and a lubricant. If necessary, the magnetic layer 4 may further contain at least one additive selected from the group consisting of an antistatic agent, an abrasive, a hardener, an anticorrosive agent, and non-magnetic reinforcing particles. The magnetic layer 4 is not limited to being composed of a coated film of a magnetic material, but may also be composed of a sputtered film or a vapor-deposited film of a magnetic material.

[0186] The arithmetic mean roughness Ra of the surface of the magnetic layer 4 is 2.0 nm or less, preferably 1.8 nm or less, and more preferably 1.6 nm or less. When the arithmetic mean roughness Ra is 2.0 nm or less, output reduction due to spacing loss can be suppressed, thereby obtaining excellent electromagnetic conversion characteristics. The lower limit of the arithmetic mean roughness Ra of the surface of the magnetic layer 4 is preferably 0.7 nm or more, and more preferably 0.9 nm or more. When the lower limit of the arithmetic mean roughness Ra of the surface of the magnetic layer 4 is 0.7 nm or more, deterioration of running performance due to increased friction can be suppressed.

[0187] The arithmetic mean roughness Ra is calculated as follows. First, the surface of the magnetic layer 4 is observed with an atomic force microscope (AFM) to obtain a 40 μm x 40 μm AFM image. A Digital Instruments Nano Scope IIIa D3100 AFM is used, with a single-crystal silicon cantilever (Note 1). Measurements are performed at a tapping frequency of 200 to 400 Hz. Next, the AFM image is divided into 512 x 512 (= 262,144) measurement points, and the height Z(i) (i: measurement point number, i = 1 to 262,144) is measured at each measurement point. The heights Z(i) at each measurement point are simply averaged (arithmetic mean) to obtain the average height (average surface) Zave (= (Z(1) + Z(2) + ... + Z(262,144)) / 262,144). Next, the deviation Z"(i) (= Z(i) - Zave) from the average center line at each measurement point is found, and the arithmetic mean roughness Ra [nm] (= (Z"(1) + Z"(2) + ... + Z"(262,144)) / 262,144) is calculated. In this case, the image is filtered using Flatten order 2 and planefit order 3 XY before being used as data. (Note 1) Nano World SPM probe NCH normal type PointProbe L (cantilever length) = 125 μm

[0188] Average thickness t of the magnetic layer 4 m The upper limit of the average thickness t of the magnetic layer 4 is 80 nm or less, preferably 70 nm or less, and more preferably 50 nm or less. mIf the upper limit value 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, and therefore, even better electromagnetic conversion characteristics can be obtained.

[0189] Average thickness t of the magnetic layer 4 m The lower limit of the average thickness t of the magnetic layer 4 is preferably 35 nm or more. m If the lower limit of is 35 nm or more, when an MR head is used as the reproducing head, output can be ensured, and therefore even better electromagnetic conversion characteristics can be obtained.

[0190] Average thickness t of the magnetic layer 4 m is determined as follows. First, the magnetic tape MT housed in the cartridge 10 is unwound, and three samples are cut out from the magnetic tape MT at three positions: 10 m, 30 m, and 50 m from one end of the outermost circumference. Next, each sample (the magnetic tape MT to be measured) is thinned by processing using an FIB method or the like. When using the FIB method, a carbon layer and a tungsten layer are formed as protective films as a pretreatment for observing the cross-sectional TEM image described below. The carbon layer is formed by vapor deposition on the surface of the magnetic tape MT facing the magnetic layer 4 and the surface facing the back layer 5, and the tungsten layer is further formed by vapor deposition or sputtering on the surface facing the magnetic layer 4. The thinning is performed along the longitudinal direction (longitudinal direction) of the magnetic tape MT. In other words, the thinning results in a cross section parallel to both the longitudinal direction and the thickness direction of the magnetic tape MT.

[0191] The cross section of the obtained thinned sample is observed under a transmission electron microscope (TEM) under the following conditions to obtain a TEM image of each thinned sample. Note that the magnification and acceleration voltage may be adjusted appropriately depending on the type of device. Device: TEM (H9000NAR manufactured by Hitachi, Ltd.) Acceleration voltage: 300 kV Magnification: 100,000 times

[0192] Next, using the TEM image of each obtained sliced ​​sample, the thickness of the magnetic layer 4 is measured at 10 or more positions on each sliced ​​sample. As described above, since the slices are made along the longitudinal direction of the magnetic tape MT, the 10 measurement positions on each sliced ​​sample are randomly selected from the test piece so that they are different positions in the longitudinal direction of the magnetic tape MT. The measured values ​​of each obtained sliced ​​sample (thicknesses of the magnetic layer 4 at 30 points in total) are simply averaged (arithmetic average) to obtain an average value, which is the average thickness t of the magnetic layer 4. m Let [nm].

[0193] (Magnetic Powder) The 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 iron oxide (ε-iron oxide) (hereinafter referred to as "ε-iron oxide particles"), or particles containing Co-containing spinel ferrite (hereinafter referred to as "cobalt ferrite particles"). The magnetic powder preferably has magnetocrystalline anisotropy and uniaxial anisotropy.

[0194] (Hexagonal Ferrite Particles) Hexagonal ferrite particles have, for example, a plate shape such as a hexagonal plate or a columnar shape such as a hexagonal column (however, the thickness or height is smaller than the major axis of the plate surface or base). In this specification, the term "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. Specifically, the hexagonal ferrite may 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. Strontium ferrite may further contain at least one of Ba, Pb, and Ca in addition to Sr.

[0195] More specifically, hexagonal ferrite has the general formula MFe 12 O 19It has an average composition represented by the formula: where 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 also be a combination of Sr and one or more metals selected from the group consisting of Ba, Pb, and Ca. In the above general formula, a portion of Fe may be substituted with another metal element.

[0196] When the magnetic powder contains hexagonal ferrite particles, 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, particularly preferably 14 nm or more and 17 nm or less, and most preferably 14 nm or more and 16 nm or less. When the average particle size of the magnetic powder is 22 nm or less, even better electromagnetic conversion characteristics (e.g., SNR) can be obtained in high-recording-density magnetic tapes MT. On the other hand, when 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 (e.g., SNR) can be obtained.

[0197] When the magnetic powder contains hexagonal ferrite particles, 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 or more and 2.7 or less. When the average aspect ratio of the magnetic powder is within the range of 1.0 or more and 3.0 or less, aggregation of the magnetic powder can be suppressed. Furthermore, when the magnetic powder is vertically oriented in the process of forming the magnetic layer 4, the resistance applied to the magnetic powder can be suppressed. Therefore, the vertical orientation of the magnetic powder can be improved.

[0198] When the magnetic powder contains hexagonal ferrite particles, the average particle size and average aspect ratio of the magnetic powder can be determined as follows. First, the magnetic tape MT to be measured is processed and thinned by FIB or other methods. When using FIB, a carbon layer and a tungsten layer are formed as protective films as a pretreatment for observing the cross-sectional TEM image described below. The carbon layer is formed by vapor deposition on the surface of the magnetic tape MT facing the magnetic layer 4 and the surface facing the back layer 5, and the tungsten layer is further formed by vapor deposition or sputtering on the surface facing the magnetic layer 4. The thinning is performed along the longitudinal direction (longitudinal direction) of the magnetic tape MT. In other words, the thinning results in a cross section parallel to both the longitudinal direction and the thickness direction of the magnetic tape MT.

[0199] The cross section of the obtained thin sample is observed using a transmission electron microscope (H-9500 manufactured by Hitachi High-Technologies Corporation) at an acceleration voltage of 200 kV and a total magnification of 500,000 times, so as to include the entire magnetic layer 4 in the thickness direction of the magnetic layer 4, and a TEM photograph is taken. The number of TEM photographs prepared is such that 50 particles can be extracted that can measure the plate diameter DB and plate thickness DA shown below.

[0200] In this specification, the size of a hexagonal ferrite particle (hereinafter referred to as "particle size") is defined as the plate diameter DB, which is the major axis of the plate surface or bottom surface, when the particle shape observed in the TEM photograph is plate-like or columnar (however, the thickness or height is smaller than the major axis of the plate surface or bottom surface). The thickness or height of the particle observed in the TEM photograph is defined as the plate thickness DA. When the thickness or height of a particle is not constant within a single particle, the thickness or height of the largest particle is defined as the plate thickness DA.

[0201] Next, 50 particles are selected from the TEM photograph based on the following criteria: Particles with parts outside the field of view of the TEM photograph are not measured, and only particles with a clear outline and that exist independently are measured. When particles overlap, particles with a clear boundary between them and whose overall shape can be determined are measured as individual particles, but particles with an unclear boundary and whose overall shape cannot be determined are not measured, as their shape cannot be determined.

[0202] The plate thickness DA of each of the selected 50 particles is measured. The plate thicknesses DA thus obtained are simply averaged (arithmetic average) to obtain the average plate thickness DA. ａｖｅ Calculate the average plate thickness DA ａｖｅ is the average particle plate thickness. Next, the plate diameter DB of each magnetic powder is measured. In order to measure the particle plate diameter DB, 50 particles whose particle plate diameter DB can be clearly confirmed are selected from the TEM photograph. The plate diameter DB of each of the selected 50 particles is measured. The plate diameter DBs thus obtained are simply averaged (arithmetic averaged) to obtain the average plate diameter DB. ａｖｅ Average plate diameter DB ａｖｅ is the average grain size. And the average plate thickness DA ａｖｅ and average plate diameter DB ａｖｅ The average aspect ratio of the particles (DB ａｖｅ / DA ａｖｅ ) is required.

[0203] When the magnetic powder contains hexagonal ferrite particles, the average particle volume of the magnetic powder is preferably 500 nm ３ 2500nm or more ３ Less than 500 nm, more preferably ３ 1600nm or more ３ Less than 500 nm, more preferably ３ 1500nm or more ３ Below 600 nm, particularly preferably ３ 1200nm or more ３ Below 600 nm, most preferably ３ 1000nm or more ３ The average particle volume of the magnetic powder is 2500 nm or less. ３When the average particle size of the magnetic powder is 22 nm or less, the same effect as when the average particle volume of the magnetic powder is 500 nm or less can be obtained. ３ If the average particle size of the magnetic powder is 13 nm or more, the same effect as that obtained when the average particle size of the magnetic powder is 13 nm or more can be obtained.

[0204] The average particle volume of the magnetic powder can be calculated as follows. First, as described above in relation to the method for calculating the average particle size of the magnetic powder, the average major axis length DA ave and average plate diameter DB ave Next, the average volume V of the magnetic powder is calculated using the following formula:

[0205] (ε-Iron Oxide Particles) ε-Iron oxide particles are hard magnetic particles that can achieve high coercivity even in the form of fine particles. ε-Iron oxide particles have a spherical or cubic shape. In this specification, spherical includes an almost spherical shape. Furthermore, cubic includes an almost cubic shape. Because ε-Iron oxide particles have the above-described shape, when ε-Iron oxide particles are used as magnetic particles, the contact area between particles in the thickness direction of the magnetic tape MT can be reduced and particle aggregation can be suppressed compared to when hexagonal plate-shaped barium ferrite particles are used as magnetic particles. Therefore, the dispersibility of the magnetic powder can be improved, and even better electromagnetic conversion characteristics (e.g., SNR) can be obtained.

[0206] The ε-iron oxide particles have a composite particle structure such as a core-shell structure, a Janus structure, or a surface-bonded structure.

[0207] A part of the composite structure contains ε-iron oxide, which preferably has ε-Fe2O3 crystals as the main phase, and more preferably is made of a single phase of ε-Fe2O3.

[0208] It is preferable that the other parts of the composite structure behave like a single particle in terms of magnetic properties by exchange coupling between the ε iron oxide part and the other parts.

[0209] The remaining portion is preferably a soft magnetic layer 4, and includes a soft magnetic material such as α-Fe, a Ni-Fe alloy, or an Fe-Si-Al alloy. The α-Fe may be obtained by reducing ε-iron oxide contained in the core portion. Alternatively, even if it is not soft magnetic, it may have a higher σs and a lower Hc than ε-iron oxide.

[0210] The ε-iron oxide particles may contain an additive instead of the above structure, or may have the above structure and contain an additive. In this case, a portion of the Fe in the ε-iron oxide particles is substituted with the additive. By containing the additive in the ε-iron oxide particles, the coercivity Hc of the ε-iron oxide particles as a whole can be adjusted to a coercivity Hc suitable for recording, thereby improving ease of recording. The additive is a metal element other than iron, preferably a trivalent metal element, more preferably at least one of Al, Ga, and In, and even more preferably at least one of Al and Ga.

[0211] Specifically, the ε-iron oxide containing additives is ε-Fe 2-x M x The additive contains a metal element other than iron, and more preferably contains at least one of Al (aluminum), Ga (gallium), In (indium), Co (cobalt), Mn (manganese), Zr (zirconium), Hf (hafnium), Cs (cesium), Ti (titanium), Sm (samarium), Nd (neodymium), Pr (praseodymium), and Tb (terbium).

[0212] When the magnetic powder contains ε-iron oxide particles, the average particle size of the magnetic powder is preferably 10 nm to 20 nm, more preferably 10 nm to 18 nm, even more preferably 10 nm to 16 nm, particularly preferably 10 nm to 15 nm, and most preferably 10 nm to 14 nm. In magnetic tape MT, the actual magnetization region is a region half the size of the recording wavelength. Therefore, by setting the average particle size of the magnetic powder to less than half the shortest recording wavelength, even better electromagnetic conversion characteristics (e.g., SNR) can be obtained. Therefore, when the average particle size of the magnetic powder is 20 nm or less, even better electromagnetic conversion characteristics (e.g., SNR) can be obtained in high-recording-density magnetic tape MT (e.g., magnetic tape MT configured to record signals at the shortest recording wavelength of 40 nm or less). On the other hand, when 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 (e.g., SNR) can be obtained.

[0213] When the magnetic powder contains ε-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, even more preferably 1.0 or more and 2.1 or less, and particularly preferably 1.0 or more and 1.8 or less. When the average aspect ratio of the magnetic powder is within the range of 1.0 or more and 3.0 or less, aggregation of the magnetic powder can be suppressed. Furthermore, when the magnetic powder is vertically oriented in the process of forming the magnetic layer 4, the resistance applied to the magnetic powder can be suppressed. Therefore, the vertical orientation of the magnetic powder can be improved.

[0214] When the magnetic powder contains ε-iron oxide particles, the average particle size and average aspect ratio of the magnetic powder can be determined as follows. First, the magnetic tape MT to be measured is processed and thinned by a method such as FIB (Focused Ion Beam). When using the FIB method, a carbon layer and a tungsten layer are formed as protective layers as a pretreatment for observing the cross-sectional TEM image described below. The carbon layer is formed by vapor deposition on the surface of the magnetic tape MT facing the magnetic layer 4 and the surface facing the back layer 5, and the tungsten layer is further formed by vapor deposition or sputtering on the surface facing the magnetic layer 4. The thinning is performed along the longitudinal direction (longitudinal direction) of the magnetic tape MT. In other words, the thinning results in a cross section parallel to both the longitudinal direction and the thickness direction of the magnetic tape MT.

[0215] The cross section of the obtained thin film sample was observed using a transmission electron microscope (H-9500 manufactured by Hitachi High-Technologies Corporation) at an acceleration voltage of 200 kV and a total magnification of 500,000 times, so as to include the entire magnetic layer 4 in the thickness direction of the magnetic layer 4, and a TEM photograph was taken. Next, 50 particles whose particle shape can be clearly confirmed were selected from the TEM photograph, and the major axis length DL and minor axis length DS of each particle were measured. Here, the major axis length DL refers to the longest distance between two parallel lines drawn from any angle so as to be tangent to the contour of each particle (the so-called maximum Feret diameter). Meanwhile, the minor axis length DS refers to the longest length of the particle in the direction perpendicular to the major axis (DL) of the particle. Next, the major axis lengths DL of the measured 50 particles were simply averaged (arithmetic mean) to obtain the average major axis length DL ave The average major axis length DL obtained in this way is ave is the average particle size of the magnetic powder. The minor axis lengths DS of the measured 50 particles are simply averaged (arithmetic mean) to obtain the average minor axis length DS ave Then, calculate the average major axis length DL ave and mean minor axis length DS ave From the average aspect ratio of the particles (DL ave / DS ave ) is required.

[0216] When the magnetic powder contains ε-iron oxide particles, the average particle volume of the magnetic powder is preferably 500 nm ３ 4000nm or more ３ Less than 500 nm, more preferably ３ 3000nm or more ３ less than or equal to 500 nm, and even more preferably ３ 2000nm or more ３ Below 600 nm, particularly preferably ３ 1600nm or more ３ Below 600 nm, most preferably ３ 1300nm or more ３ Generally, the noise of a magnetic tape MT is inversely proportional to the square root of the number of particles (i.e., proportional to the square root of the particle volume), so by making the particle volume smaller, it is possible to obtain even better electromagnetic conversion characteristics (for example, SNR). Therefore, when the average particle volume of the magnetic powder is 4000 nm ３ When the average particle size of the magnetic powder is 500 nm or less, it is possible to obtain even better electromagnetic conversion characteristics (for example, SNR), similar to the case where the average particle size of the magnetic powder is 20 nm or less. ３ If the average particle size of the magnetic powder is 10 nm or more, the same effect as that obtained when the average particle size of the magnetic powder is 10 nm or more can be obtained.

[0217] When the ε-iron oxide particles are spherical, the average particle volume of the magnetic powder can be calculated as follows: First, the average major axis length DL is calculated in the same manner as in the above-mentioned method for calculating the average particle size of the magnetic powder. ave Next, calculate the average volume V of the magnetic powder using the following formula: V = (π / 6) × DL ave 3

[0218] When the ε-iron oxide particles have a cubic shape, the average volume of the magnetic powder can be calculated as follows. The magnetic tape MT is processed and thinned by a method such as FIB (Focused Ion Beam). When the FIB method is used, a carbon film and a tungsten thin film are formed as protective films as a pretreatment for observing the cross-sectional TEM image described below. The carbon film is formed by vapor deposition on the surface of the magnetic tape MT facing the magnetic layer 4 and the surface facing the back layer 5, and the tungsten thin film is further formed by vapor deposition or sputtering on the surface facing the magnetic layer 4. The thinning is performed along the longitudinal direction (longitudinal direction) of the magnetic tape MT. In other words, the thinning results in a cross section parallel to both the longitudinal direction and the thickness direction of the magnetic tape MT.

[0219] The obtained thin film sample is observed using a transmission electron microscope (H-9500 manufactured by Hitachi High-Technologies Corporation) at an acceleration voltage of 200 kV and a total magnification of 500,000 times to observe the cross section of the magnetic layer 4 in the thickness direction so as to include the entire magnetic layer 4, and a TEM photograph is obtained. Note that the magnification and acceleration voltage may be adjusted appropriately depending on the type of device. Next, 50 particles whose particle shape is clear are selected from the TEM photograph, and the side length DC of each particle is measured. Next, the side lengths DC of the measured 50 particles are simply averaged (arithmetic mean) to obtain the average side length DC ave Next, calculate the average side length DC ave Using the following formula, the average volume V of the magnetic powder ave (particle volume) is calculated. ave = DC ave 3

[0220] (Cobalt ferrite particles) The cobalt ferrite particles preferably have uniaxial crystal anisotropy. The uniaxial crystal anisotropy of the cobalt ferrite particles allows the magnetic powder to be preferentially crystalline oriented in the thickness direction (perpendicular direction) of the magnetic tape MT. The cobalt ferrite particles have, for example, a cubic shape. In this specification, cubic shape includes a nearly cubic shape. The Co-containing spinel ferrite may further contain at least one of Ni, Mn, Al, Cu, and Zn in addition to Co.

[0221] The Co-containing spinel ferrite has an average composition represented by the following formula, for example: Co x M y FeO Z (In the formula, M is at least one metal selected from the group consisting 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. However, x and y satisfy the relationship (x+y)≦1.0. z is a value within the range of 3≦z≦4. A portion of Fe may be substituted with another metal element.)

[0222] When the magnetic powder contains cobalt ferrite particles, 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. When the average particle size of the magnetic powder is 16 nm or less, even better electromagnetic conversion characteristics (e.g., SNR) can be obtained in high-recording-density magnetic tapes MT. On the other hand, when 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 (e.g., 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 ε-iron oxide particles.

[0223] When the magnetic powder contains cobalt ferrite 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, even more preferably 1.0 or more and 2.1 or less, and particularly preferably 1.0 or more and 1.8 or less. When the average aspect ratio of the magnetic powder is within the range of 1.0 or more and 3.0 or less, aggregation of the magnetic powder can be suppressed. Furthermore, when the magnetic powder is vertically oriented in the process of forming the magnetic layer 4, the resistance applied to the magnetic powder can be suppressed. Therefore, the vertical 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 ε-iron oxide particles.

[0224] When the magnetic powder contains cobalt ferrite particles, the average particle volume of the magnetic powder is preferably 500 nm３ 4000nm or more ３ Less than 600 nm, more preferably ３ 2000nm or more ３ less than 600 nm, and even more preferably ３ 1000nm or more ３ The average particle volume of the magnetic powder is 4000 nm or less. ３ When the average particle size of the magnetic powder is 16 nm or less, the same effect as when the average particle volume of the magnetic powder is 500 nm or less can be obtained. ３ When the average particle size of the magnetic powder is 8 nm 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 ε iron oxide particles have a cubic shape.

[0225] (Binder) Examples of binders include thermoplastic resins, thermosetting resins, reactive resins, etc. Examples of thermoplastic resins include vinyl chloride, vinyl acetate, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinylidene chloride copolymers, vinyl chloride-acrylonitrile copolymers, acrylic acid ester-acrylonitrile copolymers, acrylic acid ester-vinyl chloride-vinylidene chloride copolymers, acrylic acid ester-acrylonitrile copolymers, acrylic acid ester-vinylidene chloride copolymers, acrylic acid ester-acrylonitrile copolymers, acrylic acid ester-vinylidene chloride copolymers, methacrylic acid ester-vinylidene chloride copolymers, methacrylic acid ester-vinyl chloride copolymers, methacrylic acid ester-ethylene copolymers, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymers, acrylonitrile-butadiene copolymers, polyamide resins, polyvinyl butyral, cellulose derivatives (cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose propionate, nitrocellulose), styrene-butadiene copolymers, polyurethane resins, polyester resins, amino resins, synthetic rubbers, etc.

[0226] Examples of thermosetting resins include phenolic resins, epoxy resins, polyurethane curing resins, urea resins, melamine resins, alkyd resins, silicone resins, polyamine resins, and urea formaldehyde resins.

[0227] All of the above binders may contain -SO3M, -OSO3M, -COOM, P=O(OM)2 (wherein M represents a hydrogen atom or an alkali metal such as lithium, potassium, or sodium), -NR1R2, -NR1R2R3, or the like, in order to improve the dispersibility of the magnetic powder. + X - a side chain amine having a terminal group represented by >NR1R2 + X - (wherein R1, R2, and R3 represent a hydrogen atom or a hydrocarbon group, and X - represents a halogen element ion such as fluorine, chlorine, bromine, or iodine, or an inorganic ion or an organic ion.) Polar functional groups such as -OH, -SH, -CN, and epoxy groups may also be introduced. The amount of these polar functional groups introduced into the binder is 10 -1 ~10 -8 mol / g, preferably 10 -2 ~10 -6 More preferably, it is expressed in moles / g.

[0228] (Lubricant) The lubricant contains at least one selected from, for example, a fatty acid and a fatty acid ester, preferably both a fatty acid and a fatty acid ester. The inclusion of a lubricant in the magnetic layer 4, particularly the inclusion of both a fatty acid and a fatty acid ester in the magnetic layer 4, contributes to improving the running stability of the magnetic tape MT. In particular, the magnetic layer 4 containing a lubricant and having pores achieves good running stability. This improvement in running stability is thought to be due to the lubricant adjusting the dynamic friction coefficient of the magnetic layer 4-side surface of the magnetic tape MT to a value suitable for running the magnetic tape MT.

[0229] The fatty acid may preferably be a compound represented by the following general formula (1) or (2). For example, the fatty acid may contain either or both of the compound represented by the following general formula (1) and the compound represented by the general formula (2).

[0230] The fatty acid ester may preferably be a compound represented by the following general formula (3) or (4). For example, the fatty acid ester may contain either or both of the compound represented by the following general formula (3) and the compound represented by the following general formula (4).

[0231] By including in the lubricant either one or both of the compound represented by general formula (1) and the compound represented by general formula (2), and either one or both of the compound represented by general formula (3) and the compound represented by general formula (4), it is possible to suppress an increase in the dynamic friction coefficient due to repeated recording or reproduction of the magnetic tape MT.

[0232] CH3 (CH2) k COOH (1) (In general formula (1), k is an integer selected from the range of 14 to 22, more preferably from the range of 14 to 18.)

[0233] CH3 (CH2) n CH=CH(CH2) m COOH (2) (In the general formula (2), the sum of n and m is an integer selected from the range of 12 to 20, more preferably from the range of 14 to 18.)

[0234] CH3 (CH2) p COO(CH2) q CH 3 ... (3) (In general formula (3), p is an integer selected from the range of 14 or more and 22 or less, more preferably 14 or more and 18 or less, and q is an integer selected from the range of 2 or more and 5 or less, more preferably 2 or more and 4 or less.)

[0235] CH3 (CH2) r COO-(CH2) s CH(CH3)2 (4) (In the general formula (4), r is an integer selected from the range of 14 to 22, and s is an integer selected from the range of 1 to 3.)

[0236] CH3 (CH2) r COO-CH(CH ３) (CH2) s CH(CH3) (5) (In the general formula (5), r is an integer selected from the range of 14 to 22, and s is an integer selected from the range of 1 to 3.)

[0237] (Antistatic Agent) Examples of the antistatic agent include carbon black, natural surfactants, nonionic surfactants, and cationic surfactants.

[0238] (Abrasive) Examples of the abrasive include acicular α-iron oxide obtained by dehydrating and annealing raw materials such as α-alumina, β-alumina, γ-alumina, silicon carbide, chromium oxide, cerium oxide, α-iron oxide, corundum, silicon nitride, titanium carbide, titanium oxide, 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, and, if necessary, those obtained by surface-treating these with aluminum and / or silica.

[0239] (Curing Agent) Examples of the curing agent include polyisocyanates. Examples of polyisocyanates include aromatic polyisocyanates such as an adduct of tolylene diisocyanate (TDI) and an active hydrogen compound, and aliphatic polyisocyanates such as an adduct of hexamethylene diisocyanate (HMDI) and an active hydrogen compound. The weight average molecular weight of these polyisocyanates is preferably in the range of 100 to 3,000.

[0240] (Rust inhibitor) Examples of the rust inhibitor include phenols, naphthols, quinones, heterocyclic compounds containing a nitrogen atom, heterocyclic compounds containing an oxygen atom, and heterocyclic compounds containing a sulfur atom.

[0241] (Non-magnetic reinforcing particles) Examples of non-magnetic reinforcing particles include aluminum oxide (α-, β-, or γ-alumina), chromium oxide, silicon oxide, diamond, garnet, emery, boron nitride, titanium carbide, silicon carbide, titanium carbide, and titanium oxide (rutile or anatase titanium oxide).

[0242] (Underlayer 3) The underlayer 3 serves to reduce the unevenness of the surface of the substrate 2 and adjust the unevenness of the surface of the magnetic layer 4. The underlayer 3 is a non-magnetic layer 4 containing non-magnetic powder, a binder, and a lubricant. The underlayer 3 supplies the lubricant to the surface of the magnetic layer 4. If necessary, the underlayer 3 may further contain at least one additive selected from the group consisting of an antistatic agent, a hardener, and an anti-rust agent.

[0243] Average thickness t of the underlayer 3 ２ is preferably 0.3 μm or more and 1.2 μm or less, more preferably 0.3 μm or more and 0.9 μm or less, and even more preferably 0.3 μm or more and 0.6 μm or less. ２ is the average thickness t of the magnetic layer 4 １ The average thickness t of the underlayer 3 can be calculated in the same manner as above. However, the magnification of the TEM image is adjusted appropriately depending on the thickness of the underlayer 3. ２ When the thickness is 1.2 μm or less, the magnetic tape MT has a higher elasticity due to an external force, which makes it easier to adjust the width of the magnetic tape MT by adjusting the tension.

[0244] (Non-magnetic powder) The non-magnetic powder includes, for example, at least one of inorganic particle powder and organic particle powder. The non-magnetic powder may also include 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. The inorganic particles include, for example, metals, metal oxides, metal carbonates, metal sulfates, metal nitrides, metal carbides, or metal sulfides. The shape of the non-magnetic powder may be, for example, acicular, spherical, cubic, plate-like, or other various shapes, but is not limited to these shapes.

[0245] (Binder, Lubricant) The binder and lubricant are the same as those in the magnetic layer 4 described above.

[0246] (Additives) The antistatic agent, hardener, and anticorrosive agent are the same as those in the magnetic layer 4 described above.

[0247] (Back Layer 5) The back layer 5 contains a binder and a non-magnetic powder. If necessary, the back layer 5 may further contain at least one additive selected from the group consisting of a lubricant, a curing agent, and an antistatic agent. The binder and non-magnetic powder are the same as those in the underlayer 3 described above.

[0248] 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.

[0249] The upper limit of the average thickness of the back layer 5 is preferably 0.6 μm or less. If the upper limit of the average thickness of the back layer 5 is 0.6 μm or less, the thickness of the underlayer 3 and the substrate 2 can be kept thick even when the average thickness of the magnetic tape MT is 5.6 μm or less, so that the running stability of the magnetic tape MT in a recording / reproducing device can be maintained. The lower limit of the average thickness of the back layer 5 is not particularly limited, but is, for example, 0.2 μm or more.

[0250] Average thickness t of the back layer 5 b is calculated as follows: First, the average thickness t of the magnetic tape MT T Measure the average thickness t T The method for measuring the thickness is as described in the "Average Thickness of Magnetic Tape MT" below. Next, the back layer 5 of the sample is removed with a solvent such as MEK (methyl ethyl ketone) or dilute hydrochloric acid. Next, the thickness of the sample is measured at five or more points using a Mitutoyo Laser Hologram (LGH-110C), and the measured values ​​are simply averaged (arithmetic mean) to obtain the average thickness t B Then, the average thickness t of the back layer 5 is calculated using the following formula: b The measurement position is selected randomly from the sample. b [μm] = t T [μm]-t B [μm]

[0251] The back layer 5 has a surface on which a large number of protrusions are provided. The large number of protrusions are intended to form a large number of holes in the surface of the magnetic layer 4 when the magnetic tape MT is wound into a roll. The large number of holes is made up of, for example, a large number of non-magnetic particles protruding from the surface of the back layer 5.

[0252] (Average thickness of magnetic tape MT) Average thickness of magnetic tape MT (average total thickness) t T The upper limit of the average thickness t of the magnetic tape MT is 5.4 μm or less, preferably 5.2 μm or less, more preferably 4.9 μm or less, and even more preferably 4.6 μm or less. T When the average thickness t of the magnetic tape MT is 5.4 μm or less, the recording capacity that can be recorded in one data cartridge 10 can be increased compared to that of a general magnetic tape MT. T The lower limit of the thickness is not particularly limited, but is, for example, 3.5 μm or more.

[0253] Average thickness t of magnetic tape MT T is obtained as follows. First, a 1 / 2 inch wide magnetic tape MT is prepared and cut into a length of 250 mm to prepare a sample. Next, the thickness of the sample is measured at five or more points using a Mitutoyo Laser Hologram (LGH-110C) as a measuring device, and the measured values ​​are simply averaged (arithmetic mean) to obtain the average value t T The measurement position is selected randomly from the sample.

[0254] (Coercive force Hc) The upper limit of the coercive force Hc2 of the magnetic layer 4 in the longitudinal direction of the magnetic tape MT is preferably 2200 Oe or less, more preferably 2000 Oe or less, more preferably 1800 Oe or less, and even more preferably 1600 Oe or less. If the coercive force Hc2 of the magnetic layer 4 in the longitudinal direction is 2200 Oe or less, sufficient electromagnetic conversion characteristics can be obtained even at high recording densities.

[0255] The lower limit of the coercive force Hc2 of the magnetic layer 4 measured in the longitudinal direction of the magnetic tape MT is preferably 1000 Oe or more. When the coercive force Hc2 of the magnetic layer 4 measured in the longitudinal direction is 1000 Oe or more, demagnetization due to leakage flux from the recording head can be suppressed.

[0256] The coercive force Hc2 is determined as follows. First, the magnetic tape MT housed in the cartridge 10 is unwound, and a piece of the magnetic tape MT is cut out at a position 30 m from one end of the outermost circumference. Three pieces of the magnetic tape MT are stacked with double-sided tape so that the longitudinal direction of the magnetic tape MT is the same, and then punched out with a φ6.39 mm punch to prepare a measurement sample. At this time, marking is performed with any non-magnetic ink so that the longitudinal direction (running direction) of the magnetic tape MT can be identified. Then, the M-H loop of the measurement sample (the entire magnetic tape MT) corresponding to the longitudinal direction (running direction) of the magnetic tape MT is measured using a vibrating sample magnetometer (VSM). Next, the coating film (underlayer 3, magnetic layer 4, back layer 5, etc.) of the magnetic tape MT cut out above is wiped off with acetone, ethanol, etc., leaving only the substrate 2. Three of the obtained substrates 2 are then stacked with double-sided tape and punched out with a φ6.39 mm punch to prepare a sample for background correction (hereinafter simply referred to as a "correction sample"). Thereafter, the M-H loop of the correction sample (substrate 2) corresponding to the perpendicular direction of the substrate 2 (the perpendicular direction of the magnetic tape MT) is measured using a VSM.

[0257] The MH loop of the measurement sample (the entire magnetic tape MT) and the MH loop of the correction sample (substrate 2) are measured using a high-sensitivity vibrating sample magnetometer "VSM-P7-15" manufactured by Toei Industry Co., Ltd. The measurement conditions are as follows: 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, number of MH averages: 20.

[0258] After obtaining the M-H loop of the measurement sample (the entire magnetic tape MT) and the M-H loop of the correction sample (substrate 2), background correction is performed by subtracting the M-H loop of the correction sample (substrate 2) from the M-H loop of the measurement sample (the entire magnetic tape MT), resulting in the background-corrected M-H loop. This background correction calculation is performed using the measurement and analysis program included with the VSM-P7-15. The coercive force Hc2 is calculated from the obtained background-corrected M-H loop. This calculation is performed using the measurement and analysis program included with the VSM-P7-15. All of the above M-H loop measurements are performed at 25°C ± 2°C and 50% RH ± 5% RH. Furthermore, "demagnetization field correction" is not performed when measuring the M-H loop in the longitudinal direction of the magnetic tape MT.

[0259] (Squareness Ratio) The squareness ratio S1 of the magnetic layer 4 in the perpendicular direction (thickness direction) of the magnetic tape MT is preferably 60% or more, more preferably 65% ​​or more, even more preferably 70% or more, particularly preferably 75% or more, and most preferably 80% or more. When the squareness ratio S1 is 60% or more, the perpendicular orientation of the magnetic powder is sufficiently high, and therefore, even better electromagnetic conversion characteristics (e.g., SNR) can be obtained.

[0260] The squareness ratio S1 in the vertical direction is determined as follows. First, the magnetic tape MT housed in the cartridge 10 is unwound, and the magnetic tape MT is cut out at a position 30 m from one end of the outermost circumference. Three pieces of the magnetic tape MT are stacked with double-sided tape so that the longitudinal direction of the magnetic tape MT is the same, and then punched out with a φ6.39 mm punch to prepare a measurement sample. At this time, marking is performed with any non-magnetic ink so that the longitudinal direction (running direction) of the magnetic tape MT can be identified. Then, the M-H loop of the measurement sample (the entire magnetic tape MT) corresponding to the longitudinal direction (running direction) of the magnetic tape MT is measured using a vibrating sample magnetometer (VSM). Next, the coating film (underlayer 3, magnetic layer 4, back layer 5, etc.) of the magnetic tape MT cut out above is wiped off with acetone, ethanol, etc., leaving only the substrate 2. Three of the obtained substrates 2 are then stacked with double-sided tape and punched out with a φ6.39 mm punch to prepare a sample for background correction (hereinafter simply referred to as a "correction sample"). Thereafter, the M-H loop of the correction sample (substrate 2) corresponding to the perpendicular direction of the substrate 2 (the perpendicular direction of the magnetic tape MT) is measured using a VSM.

[0261] The MH loop of the measurement sample (the entire magnetic tape MT) and the MH loop of the correction sample (substrate 2) are measured using a high-sensitivity vibrating sample magnetometer "VSM-P7-15" manufactured by Toei Industry Co., Ltd. The measurement conditions are as follows: 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, number of MH averages: 20.

[0262] After obtaining the M-H loop of the measurement sample (the entire magnetic tape MT) and the M-H loop of the correction sample (substrate 2), background correction is performed by subtracting the M-H loop of the correction sample (substrate 2) from the M-H loop of the measurement sample (the entire magnetic tape MT), thereby obtaining the M-H loop after background correction. This background correction calculation is performed using the measurement and analysis program included with the "VSM-P7-15 Model."

[0263] The saturation magnetization Ms (emu) and residual magnetization Mr (emu) of the M-H loop after background correction are substituted into the following formula to calculate the squareness ratio S1 (%). Note that all of the above M-H loop measurements are performed at 25°C ± 2°C and 50% RH ± 5% RH. Also, no "demagnetizing field correction" is performed when measuring the M-H loop in the perpendicular direction to the magnetic tape MT. Note that this calculation uses the measurement and analysis program included with the "VSM-P7-15 model." Squareness ratio S1 (%) = (Mr / Ms) × 100

[0264] The squareness ratio S2 of the magnetic layer 4 in the longitudinal direction (running direction) of the magnetic tape MT is preferably 35% or less, more preferably 30% or less, even more preferably 25% or less, particularly preferably 20% or less, and most preferably 15% or less. When the squareness ratio S2 is 35% or less, the perpendicular orientation of the magnetic powder is sufficiently high, and therefore even better electromagnetic conversion characteristics (e.g., SNR) can be obtained.

[0265] The squareness ratio may be any value that satisfies either the perpendicular or longitudinal direction. In particular, for magnetic tapes MT with a thin magnetic layer of 100 nm or less, it is better to place more importance on the squareness ratio in the longitudinal direction than on the perpendicular direction, where the influence of the demagnetizing field is more likely to be different.

[0266] The squareness ratio S2 in the longitudinal direction is determined 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 MT and the substrate 2.

[0267] (Surface roughness Rb of the back surface) Surface roughness of the back surface (surface roughness of the back layer 5) R b But, R bThe surface roughness R of the back surface is preferably ≦6.0 nm. b When the content of the magnetic layer is within the above range, even better electromagnetic conversion characteristics can be obtained.

[0268] The present technology can also be configured as follows: (1) A magnetic recording medium comprising: a magnetic tape having a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt that is inclined with respect to the tape width direction and a second azimuth tilt that is inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and a servo pattern on which the first azimuth tilt and the second azimuth tilt are asymmetric with respect to the tape width direction, the magnetic tape being fixed at one end side in the tape longitudinal direction to a leader pin and having an average thickness of 5.3 μm or less; and a reinforcing portion provided at one end side of the magnetic tape in the tape longitudinal direction at a position where the magnetic tape is fixed to the leader pin, the reinforcing portion reinforcing the magnetic tape. (2) The magnetic recording medium according to (1), wherein the one end side of the magnetic tape and the reinforcing portion are sandwiched between the leader pin and a clamper for fixing the magnetic tape to the leader pin, thereby fixing the one end side of the magnetic recording medium to the leader pin. (3) The magnetic recording medium according to (2) above, wherein the reinforcing portion includes an intervening portion sandwiched between the leader pin and the clamper, a first marginal portion located closer to the end than the intervening portion in the tape longitudinal direction, and a second marginal portion located closer to the center than the intervening portion in the tape longitudinal direction. (4) The magnetic recording medium according to (3) above, wherein the length of the intervening portion in the tape longitudinal direction is 2.1 mm or more and 3.4 mm or less. (5) The magnetic recording medium according to (3) or (4) above, wherein the length of the first marginal portion in the tape longitudinal direction is 0.5 mm or more and 2.5 mm or less. (6) The magnetic recording medium according to any one of (3) to (5) above, wherein the length of the second marginal portion in the tape longitudinal direction is 0.5 mm or more.(7) The magnetic recording medium according to any one of (3) to (6) above, wherein the leader pin is detachably attached to a pin holder of a take-up roller that takes up the magnetic recording medium in a data recording device that records data on the magnetic layer of the magnetic tape while reading the servo pattern, the pin holder of the take-up roller is provided at a position a predetermined distance radially inward from the outer circumferential surface of the take-up roller, and the length of the second marginal portion in the tape longitudinal direction is related to the distance. (8) The magnetic recording medium according to (7) above, wherein the length of the second marginal portion in the tape longitudinal direction is equal to or less than the distance. (9) The magnetic recording medium according to (8) above, wherein the length of the second marginal portion in the tape longitudinal direction is 2.5 mm or less. (10) The magnetic recording medium according to any one of (3) to (9) above, wherein the length of the reinforcing portion in the tape longitudinal direction is 3.1 mm or more and 8.4 mm or less. (11) The magnetic recording medium according to any one of (1) to (10) above, wherein the reinforcing portion has a thickness of 5 μm or more and 30 μm or less. (12) The magnetic recording medium according to any one of (1) to (11) above, wherein the reinforcing portion is tape-shaped. (13) The magnetic recording medium according to (12) above, wherein the reinforcing portion is a reinforcing tape provided on one surface of the magnetic tape. (14) The magnetic recording medium according to (12) above, wherein the reinforcing portion is a folded portion formed by folding one end of the magnetic tape back onto one surface of the magnetic tape.(15) A tape cartridge comprising: a tape reel; a tape-like magnetic recording medium wound on the tape reel; and a cartridge case that houses the tape reel, wherein the magnetic recording medium has a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt that is inclined with respect to the tape width direction and a second azimuth tilt that is inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and the first azimuth tilt and the second azimuth tilt are asymmetric with respect to the tape width direction, in each of a plurality of servo bands that extend in the tape longitudinal direction and are arranged in the tape width direction, the first azimuth tilt and the second azimuth tilt being asymmetric with respect to the tape width direction, the magnetic tape being fixed to a leader pin at one end side in the tape longitudinal direction and having an average thickness of 5.3 μm or less; and a reinforcing section that is provided at one end side of the magnetic tape in the tape longitudinal direction at a position where the magnetic tape is fixed to the leader pin and that reinforces the magnetic tape. (16) A magnetic recording medium comprising: a magnetic tape having a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt that is inclined with respect to the tape width direction and a second azimuth tilt that is inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and a servo pattern on each of a plurality of servo bands extending in the tape longitudinal direction and arranged in the tape width direction, the first azimuth tilt and the second azimuth tilt being asymmetric with respect to the tape width direction, a leader tape connected to the magnetic tape in the tape longitudinal direction, and a splice tape connecting the magnetic tape to the leader tape, wherein the average thickness of the magnetic tape is 5.3 μm or less, and when the difference between a joint thickness, which is the sum of the thicknesses of the leader tape and the splice tape, and the thickness of the magnetic tape is defined as a joint step, the ratio of the joint step to the thickness of the magnetic tape is 5 or less. (17) The magnetic recording medium according to (16), wherein the average thickness of the leader tape is 5.0 μm or more and 10.0 μm or less. (18) The magnetic recording medium according to (16) or (17) above, wherein the average thickness of the splice tape is 5.0 μm or more and 24.0 μm or less. (19) The magnetic recording medium according to any one of (16) to (18) above, wherein the ratio of the step height at the joint to the thickness of the magnetic tape is 4 or less.(20) The magnetic recording medium according to any one of (16) to (19), wherein the magnetic tape further has a support supporting the magnetic layer, and the average thickness of the support is 4.4 μm or less. (21) The magnetic recording medium according to (20), wherein the Young's modulus of the support is 7.2 GPa or less. (22) The magnetic recording medium according to any one of (16) to (22), wherein the length of the magnetic tape is 1000 m or more. (23) The magnetic recording medium according to any one of (16) to (22), wherein the difference between the length of the first azimuthal tilt and the length of the second azimuthal tilt is 5 μm or more. (24) The magnetic recording medium according to any one of (16) to (23), wherein the magnetic layer further has a data band arranged between the plurality of servo bands, and the data band has a plurality of data tracks with a track pitch of 800 nm or less. (25) The magnetic recording medium according to (24) above, wherein the track width of the plurality of data tracks is 500 nm or less. (26) The magnetic recording medium according to (24) or (25) above, wherein the off-track margin of the data band is 300 nm or less.(27) A tape cartridge comprising: a tape reel; a tape-like magnetic recording medium wound on the tape reel; and a cartridge case that houses the tape reel, wherein the magnetic recording medium comprises: a magnetic tape having a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt that is inclined with respect to the tape width direction and a second azimuth tilt that is inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and the first azimuth tilt and the second azimuth tilt are asymmetric with respect to the tape width direction, in each of a plurality of servo bands that extend in the tape longitudinal direction and are arranged in the tape width direction; a leader tape connected to the magnetic tape in the tape longitudinal direction; and a splice tape that connects the magnetic tape to the leader tape, wherein the average thickness of the magnetic tape is 5.3 μm or less; and when a joint step is defined as the difference between a joint thickness, which is the sum of the thicknesses of the leader tape and the splice tape, and the thickness of the magnetic tape, the ratio of the joint step to the thickness of the magnetic tape is 5 or less.

[0269] 1, 90, 93, 95...magnetic recording medium 2...substrate 4...magnetic layer 7...servo pattern 12...winding roller 50...tape cartridge 68...leader pin 72...clamper 91, 94, 96...reinforcement portion 100...data recording / reproducing device LT...leader tape MT...magnetic tape ST...splice tape

Claims

1. A magnetic recording medium comprising: a magnetic tape having a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt that is inclined with respect to the tape width direction and a second azimuth tilt that is inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and a servo pattern on which a servo pattern is asymmetric with respect to the tape width direction, the magnetic tape being fixed to a leader pin at one end side in the tape longitudinal direction and having an average thickness of 5.3 μm or less; and a reinforcing section provided at one end side of the magnetic tape in the tape longitudinal direction at the position where the magnetic tape is fixed to the leader pin, for reinforcing the magnetic tape.

2. A magnetic recording medium according to claim 1, wherein one end of the magnetic tape and a reinforcing portion are sandwiched between the leader pin and a clamper for fixing the magnetic tape to the leader pin, thereby fixing one end of the magnetic recording medium to the leader pin.

3. A magnetic recording medium according to claim 2, wherein the reinforcing portion includes an intervening portion sandwiched between the leader pin and the clamper, a first marginal portion located closer to the end of the tape than the intervening portion in the longitudinal direction of the tape, and a second marginal portion located closer to the center of the tape than the intervening portion in the longitudinal direction of the tape.

4. A magnetic recording medium according to claim 3, wherein the length of said intervening portion in the longitudinal direction of said tape is 2.1 mm or more and 3.4 mm or less.

5. A magnetic recording medium according to claim 3, wherein the length of said first margin in the longitudinal direction of said tape is 0.5 mm or more and 2.5 mm or less.

6. A magnetic recording medium according to claim 3, wherein the length of said second margin in the longitudinal direction of said tape is 0.5 mm or more.

7. A magnetic recording medium as claimed in claim 3, wherein the leader pin is detachable from a pin holding portion of a take-up roller that takes up the magnetic recording medium in a data recording device that records data on the magnetic layer of the magnetic tape while reading the servo pattern, the pin holding portion of the take-up roller is provided at a position a predetermined distance radially inward from the outer circumferential surface of the take-up roller, and the length of the second margin portion in the longitudinal direction of the tape is related to the distance.

8. A magnetic recording medium according to claim 7, wherein the length of said second margin in the longitudinal direction of said tape is equal to or less than said distance.

9. A magnetic recording medium according to claim 8, wherein the length of said second margin in the longitudinal direction of said tape is 2.5 mm or less.

10. A magnetic recording medium according to claim 3, wherein the length of said reinforcing portion in the longitudinal direction of said tape is 3.1 mm or more and 8.4 mm or less.

11. A magnetic recording medium according to claim 1, wherein the thickness of the reinforcing portion is 5 μm or more and 30 μm or less.

12. A magnetic recording medium according to claim 1, wherein the reinforcing portion is in the form of a tape.

13. A magnetic recording medium according to claim 12, wherein the reinforcing portion is a reinforcing tape provided on one side of the magnetic tape.

14. A magnetic recording medium according to claim 12, wherein the reinforcing portion is a folded portion formed by folding one end of the magnetic tape back onto one surface of the magnetic tape.

15. A tape cartridge comprising: a tape reel; a tape-like magnetic recording medium wound on the tape reel; and a cartridge case containing the tape reel, wherein the magnetic recording medium has a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt that is inclined with respect to the tape width direction and a second azimuth tilt that is inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and wherein the first azimuth tilt and the second azimuth tilt are asymmetric with respect to the tape width direction, in each of a plurality of servo bands extending in the tape longitudinal direction and arranged in the tape width direction, the first azimuth tilt and the second azimuth tilt being asymmetric with respect to the tape width direction, the magnetic tape having an average thickness of 5.3 μm or less, fixed to a leader pin at one end of the tape longitudinal direction, and a reinforcing section provided at one end of the magnetic tape in the position where the magnetic tape is fixed to the leader pin, for reinforcing the magnetic tape.

16. A magnetic recording medium comprising: a magnetic tape having a magnetic layer on which a servo pattern is recorded, the servo pattern including a first azimuth tilt that is inclined with respect to the tape width direction and a second azimuth tilt that is inclined with respect to the tape width direction in a direction different from the first azimuth tilt, and a servo pattern on each of a plurality of servo bands extending in the tape longitudinal direction and arranged in the tape width direction, the first azimuth tilt and the second azimuth tilt being asymmetric with respect to the tape width direction; a leader tape connected to the magnetic tape in the tape longitudinal direction; and a splice tape connecting the magnetic tape and the leader tape, wherein the average thickness of the magnetic tape is 5.3 μm or less, and when the difference between the thickness of the magnetic tape and the thickness of the joint portion, which is the sum of the thickness of the leader tape and the thickness of the splice tape, is defined as the joint portion step, the ratio of the joint portion step to the thickness of the magnetic tape is 5 or less.

17. A magnetic recording medium according to claim 16, wherein the average thickness of the leader tape is 5.0 μm or more and 10.0 μm or less.

18. A magnetic recording medium according to claim 16, wherein the average thickness of the splice tape is 5.0 μm or more and 24.0 μm or less.

19. A magnetic recording medium according to claim 16, wherein the ratio of the step height at the joint to the thickness of the magnetic tape is 4 or less.

20. A tape cartridge comprising: a tape reel; a tape-like magnetic recording medium wound on said tape reel; and a cartridge case containing said tape reel, wherein said magnetic recording medium comprises: a magnetic tape having a magnetic layer on which a servo pattern is recorded, said servo pattern including a first azimuth tilt that is inclined with respect to the tape width direction and a second azimuth tilt that is inclined with respect to the tape width direction in a direction different from the first azimuth tilt, said first azimuth tilt and said second azimuth tilt being asymmetric with respect to the tape width direction, in each of a plurality of servo bands extending in the tape longitudinal direction and arranged in the tape width direction; a leader tape connected to said magnetic tape in the tape longitudinal direction; and a splice tape connecting said magnetic tape and said leader tape, wherein the average thickness of said magnetic tape is 5.3 μm or less; and when a joint step is defined as the difference between a joint thickness, which is the sum of the thicknesses of the leader tape and the splice tape, and the thickness of the magnetic tape, the ratio of said joint step to the thickness of the magnetic tape is 5 or less.

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