Servo writer

Abstract

This servowriter is provided with: a travel unit that causes a magnetic recording medium in tape form to travel by feeding the magnetic recording medium out from a cartridge and winding the magnetic recording medium which has been fed out; an erase unit that erases a first servo pattern which is formed on the traveling magnetic recording medium; a head that writes a servo signal so as to form a second servo pattern on the traveling magnetic recording medium from which the first servo pattern has been erased; and a control unit that, during at least one of an accelerating travel period and a decelerating travel period of the magnetic recording medium, controls the head to write the servo signal and form the second servo pattern, which does not satisfy a standard, on the magnetic recording medium.

Description

[Technical Field]

[0001] This disclosure relates to servo light Ta Regarding. [Background technology]

[0002] In recent years, in order to improve data recording density on tape-type magnetic recording media used for computer data storage, the width of data tracks and the distance between adjacent data tracks have been narrowed. When the width of data tracks and the distance between adjacent data tracks are narrowed in this way, it becomes difficult for the read / write element of a magnetic head to trace the data tracks.

[0003] For this reason, a technology has been proposed in which a servo signal is written in advance to a magnetic recording medium, and this servo signal is read by a magnetic head, thereby servo-controlling the position of the recording / reproducing element of the magnetic head in the width direction of the magnetic recording medium (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-127730 Summary of the Invention [Problem to be solved by the invention]

[0005] The magnetic recording medium with the servo signal written thereon is housed in a cartridge case, and after undergoing a quality inspection of the magnetic recording medium, it is shipped as a product. Conventionally, if the quality of the servo signal is found to be poor during the quality inspection, the cartridge has been discarded. Therefore, if a large number of cartridges are discarded, there is a risk that cartridge productivity will decrease.

[0006] The object of the present disclosure is to provide a servo driver that can reduce the number of cartridges that are discarded. TaThe purpose is to provide [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the first disclosure provides: a running unit that runs the magnetic recording medium by feeding the tape-like magnetic recording medium from the cartridge and winding up the fed magnetic recording medium; an erasing unit that erases a first servo pattern formed on the traveling magnetic recording medium; a head that writes a servo signal onto the traveling magnetic recording medium from which the first servo pattern has been erased, thereby forming a second servo pattern; Accelerated running period of magnetic recording media The first unused area corresponding to and Magnetic recording media Decelerated driving period The second unused area corresponding to At least one of region In Erasing the first servo pattern and The head is controlled to write the servo signal, and the second servo pattern that does not meet the standard is written. At least one area A control unit formed in The servo writer is provided with:

[0008] The second disclosure is: a running unit that runs the magnetic recording medium by feeding the tape-like magnetic recording medium from the cartridge and winding up the fed magnetic recording medium; an erasing unit that erases a first servo pattern formed on the traveling magnetic recording medium; a head that writes a servo signal onto the traveling magnetic recording medium from which the first servo pattern has been erased, thereby forming a second servo pattern; Accelerated running period of magnetic recording media The first unused area corresponding to and Magnetic recording media Decelerated driving period The second unused area corresponding to At least one of region In After erasing the first servo pattern Do not write servo signals Eraser and A control unit that controls the head The servo writer is provided with:

[0009] The third disclosure is: a magnetic layer; a wound tape-like magnetic recording medium; A reel capable of winding up a magnetic recording medium is provided. A case for accommodating a magnetic recording medium; Equipped with A pin is provided at one end of the outer periphery of the magnetic recording medium, The magnetic recording medium is Includes a magnetic layer It has unused areas, The unused area is provided in a portion that is not fixed to the pin and the reel, The unused area is a cartridge in which a servo pattern that does not meet the standard is formed, or in which no servo pattern is formed. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an exploded perspective view showing an example of the configuration of a cartridge. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the configuration of a magnetic tape. [Figure 3] FIG. 3 is a schematic diagram showing an example of the layout of the data band and the servo band. [Figure 4] FIG. 4 is an enlarged view showing an example of the configuration of a data band. [Figure 5] FIG. 5 is an enlarged view showing an example of the configuration of a servo band. [Figure 6] FIG. 6 is a schematic diagram showing an example of a format of a magnetic tape. [Figure 7] Figure 7A is a schematic diagram showing a first example of a servo pattern that does not meet the standard, Figure 7B is a schematic diagram showing a second example of a servo pattern that does not meet the standard, and Figure 7C is a schematic diagram showing an example of a servo pattern that meets the standard. [Figure 8] FIG. 8 is a schematic diagram showing an example of the configuration of a servo writer for a cartridge. [Figure 9] FIG. 9 is a schematic diagram showing an example of the configuration of a servo signal recording system. [Figure 10] FIG. 10 is a schematic diagram showing an example of the configuration of a pancake servo writer. [Figure 11]FIG. 11 is a schematic diagram showing an example of the configuration of a winder. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present disclosure will be described in the following order with reference to the drawings. In all the drawings of the following embodiments, the same or corresponding parts are designated by the same reference numerals. 1 Cartridge configuration 2. Magnetic Tape Configuration 3 Magnetic Tape Format 4. Servo writer configuration for cartridges 5. Operation of the cartridge servo writer 6. Servo signal recording system configuration 7 Operation of the servo signal recording system 8. Effects 9 Variations

[0012] [1 cartridge configuration] FIG. 1 is an exploded perspective view showing an example of the configuration of a cartridge 10. The cartridge 10 is a magnetic tape cartridge conforming to the LTO (Linear Tape-Open) standard. The cartridge 10 includes a cartridge case 12 composed of a lower shell 12A and an upper shell 12B, a reel 13 wound with a magnetic tape (a tape-like magnetic recording medium) MT, a reel lock 14 and a reel spring 15 for locking the rotation of the reel 13, a spider 16 for unlocking the reel 13, a sliding door 17 for opening and closing a tape outlet 12C provided in the cartridge case 12 across the lower shell 12A and the upper shell 12B, a door spring 18 for biasing the sliding door 17 to a closed position of the tape outlet 12C, a write protect 19 for preventing accidental erasure, and a cartridge memory 11. The reel 13 is generally disk-shaped with an opening in the center and is composed of a reel hub 13A and a flange 13B made of a hard material such as plastic. One end of the magnetic tape MT is provided with a leader pin 20.

[0013] The cartridge memory 11 is provided near one corner of the cartridge 10. When the cartridge 10 is loaded into the recording / playback device, the cartridge memory 11 faces the reader / writer of the recording / playback device. The cartridge memory 11 communicates with the recording / playback device, specifically with the reader / writer of the recording / playback device, using a wireless communication standard that complies with the LTO standard.

[0014] [2 Magnetic Tape Configuration] 2 is a cross-sectional view showing an example of the configuration of a magnetic tape MT. The magnetic tape MT is a tape-shaped magnetic recording medium, and includes a long substrate 41, an underlayer 42 provided on one main surface (first main surface) of the substrate 41, a magnetic layer 43 provided on the underlayer 42, and a back layer 44 provided on the other main surface (second main surface) of the substrate 41. Note that the underlayer 42 and the back layer 44 are provided as needed and may be omitted. The magnetic tape MT may be a perpendicular recording type magnetic recording medium or a longitudinal recording type magnetic recording medium.

[0015] The magnetic tape MT is preferably used in a recording / playback device equipped with a ring-type head as a recording head. The magnetic tape MT is preferably configured so that the width of the magnetic tape MT can be kept constant or nearly constant by adjusting the longitudinal tension of the magnetic tape MT using the recording / playback device while it is running.

[0016] (Base) The substrate 41 is a non-magnetic support that supports the underlayer 42 and the magnetic layer 43. The substrate 41 has the shape of a long film. The upper limit of the average thickness of the substrate 41 is preferably 4.2 μm or less, more preferably 3.8 μm or less, and even more preferably 3.4 μm or less. If the upper limit of the average thickness of the substrate 41 is 4.2 μm or less, the recording capacity that can be recorded in one data cartridge can be increased compared to that of general magnetic tape. The lower limit of the average thickness of the substrate 41 is preferably 3 μm or more, more preferably 3.2 μm or more. If the lower limit of the average thickness of the substrate 41 is 3 μm or more, a decrease in the strength of the substrate 41 can be suppressed.

[0017] The average thickness of the substrate 41 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 of the sample other than the substrate 41 (i.e., the underlayer 42, magnetic layer 43, and back layer 44) are removed with a solvent such as MEK (methyl ethyl ketone) or dilute hydrochloric acid. Next, using a Mitutoyo Laser Hologram (LGH-110C) as a measuring device, the thickness of the sample (substrate 41) is measured at five or more positions, and these measurements are simply averaged (arithmetic mean) to calculate the average thickness of the substrate 41. Note that the measurement positions are selected randomly from the sample.

[0018] The substrate 41 preferably contains polyester. By including polyester in the substrate 41, the Young's modulus in the longitudinal direction of the substrate 41 can be reduced. Therefore, by adjusting the tension in the longitudinal direction of the magnetic tape MT during running using a recording / reproducing device (drive), the width of the magnetic tape MT can be kept constant or approximately constant.

[0019] The polyester may include, 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 41 includes two or more polyesters, the two or more polyesters may be mixed, copolymerized, or laminated. At least one of the terminals and side chains of the polyester may be modified.

[0020] The inclusion of polyester in the base 41 can be confirmed, for example, as follows. First, in the same manner as in the method for measuring the average thickness of the base 41, layers other than the base 41 are removed from the sample. Next, an IR spectrum of the sample (base 41) is obtained by infrared absorption spectrometry (IR). Based on this IR spectrum, it can be confirmed that the base 41 contains polyester.

[0021] In addition to polyester, the base 41 may further contain, for example, at least one of polyamide, polyimide, and polyamideimide, or at least one of polyamide, polyimide, polyamideimide, polyolefins, cellulose derivatives, vinyl resins, and 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.

[0022] When the base 41 contains a polymer resin other than polyester, it is preferable that the base 41 contains polyester as a main component. Here, the main component means the component with the largest content (mass ratio) among the polymer resins contained in the base 41. When the base 41 contains a polymer resin other than polyester, the polyester and the polymer resin other than polyester may be mixed or copolymerized.

[0023] The substrate 41 may be biaxially stretched in the longitudinal direction and the width direction. The polymer resin contained in the substrate 41 is preferably oriented in a direction oblique to the width direction of the substrate 41.

[0024] (magnetic layer) The magnetic layer 43 is a recording layer for recording signals using a magnetization pattern. The magnetic layer 43 may be a recording layer for perpendicular recording or a recording layer for longitudinal recording. The magnetic layer 43 contains, for example, a magnetic powder and a binder. If necessary, the magnetic layer 43 may further contain at least one additive selected from the group consisting of a lubricant, an antistatic agent, an abrasive, a hardener, an anticorrosive agent, and non-magnetic reinforcing particles.

[0025] The average thickness t of the magnetic layer 43 m The upper limit of the average thickness t of the magnetic layer 43 is 80 nm or less, preferably 70 nm or less, and more preferably 50 nm or less. m If the upper limit is 80 nm or less, when a ring-type head is used as the recording head, the influence of the demagnetizing field can be reduced, and therefore, even better electromagnetic conversion characteristics can be obtained.

[0026] The average thickness t of the magnetic layer 43 m The lower limit of the average thickness t of the magnetic layer 43 is preferably 35 nm or more. m If the lower limit is 35 nm or more, output can be ensured when a magnetoresistive (MR) head, giant magnetoresistive (GMR) head, or tunneling magnetoresistive (TMR) head is used as the reproducing head, thereby achieving even better electromagnetic conversion characteristics.

[0027] The average thickness t of the magnetic layer 43 m is obtained as follows. First, the magnetic tape MT to be measured is processed and thinned by FIB 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 43 and the surface facing the back layer 44, and the tungsten layer is further formed by vapor deposition or sputtering on the surface facing the magnetic layer 43. The thinning is performed along the length (longitudinal direction) of the magnetic tape MT. In other words, the thinning forms a cross section parallel to both the longitudinal and thickness directions of the magnetic tape MT.

[0028] 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. Note that the magnification and acceleration voltage may be adjusted appropriately depending on the type of device. Apparatus: TEM (Hitachi H9000NAR) Accelerating voltage: 300 kV Magnification: 100,000x

[0029] Next, using the obtained TEM image, the thickness of the magnetic layer 43 is measured at at least 10 positions in the longitudinal direction of the magnetic tape MT. The obtained measured values ​​are simply averaged (arithmetic average) to obtain the average thickness t m The position where the above measurement is performed shall be selected randomly from the test piece.

[0030] (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-type 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"). It is preferable that the magnetic powder has a crystal orientation preferentially in the thickness direction (perpendicular direction) of the magnetic tape MT.

[0031] (Hexagonal ferrite particles) Hexagonal ferrite particles have a plate shape, such as a hexagonal plate shape. In this specification, a 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.

[0032] More specifically, hexagonal ferrites have the general formula MFe 12 O 19 The alloy 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, part of Fe may be substituted with another metal element.

[0033] (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 nearly spherical. Furthermore, cubic includes nearly cubic. 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. This improves the dispersibility of the magnetic powder and allows for even better electromagnetic conversion characteristics (e.g., SNR).

[0034] The ε-iron oxide particles have a core-shell structure. Specifically, the ε-iron oxide particles have a core and a two-layer shell structure surrounding the core. The two-layer shell structure includes a first shell portion provided on the core and a second shell portion provided on the first shell portion.

[0035] The core portion contains ε-iron oxide. The ε-iron oxide contained in the core portion preferably has ε-Fe2O3 crystals as a main phase, and more preferably is composed of a single phase ε-Fe2O3.

[0036] The first shell portion covers at least a portion of the periphery of the core portion. Specifically, the first shell portion may cover a portion of the periphery of the core portion, or may cover the entire periphery of the core portion. From the viewpoint of ensuring sufficient exchange coupling between the core portion and the first shell portion and improving magnetic properties, it is preferable that the first shell portion covers the entire surface of the core portion.

[0037] The first shell portion is a so-called soft magnetic layer 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.

[0038] The second shell portion is an oxide coating serving as an anti-oxidation layer. The second shell portion contains α-iron oxide, aluminum oxide, or silicon oxide. The α-iron oxide includes at least one iron oxide selected from Fe3O4, Fe2O3, and FeO. When the first shell portion contains α-Fe (soft magnetic material), the α-iron oxide may be obtained by oxidizing the α-Fe contained in the first shell portion.

[0039] By having the first shell portion as described above, the coercivity Hc of the core portion alone can be maintained at a high value to ensure thermal stability, while the coercivity Hc of the entire ε-iron oxide particle (core-shell particle) can be adjusted to a coercivity Hc suitable for recording. Furthermore, by having the second shell portion as described above, the ε-iron oxide particles can be prevented from deteriorating in their properties due to exposure to air during and before the manufacturing process of the magnetic tape MT, which can lead to rust and other damage to the particle surface. Therefore, deterioration of the properties of the magnetic tape MT can be prevented.

[0040] The ε-iron oxide particles may have a shell part with a single layer structure. In this case, the shell part has the same structure as the first shell part. However, from the viewpoint of suppressing deterioration of the properties of the ε-iron oxide particles, it is preferable that the ε-iron oxide particles have a shell part with a two-layer structure, as described above.

[0041] The ε-iron oxide particles may contain an additive instead of the core-shell structure, or may have a core-shell structure and contain an additive. In this case, part of the Fe in the ε-iron oxide particles is substituted with the additive. By containing the additive in the ε-iron oxide particles, the coercivity Hc of the entire ε-iron oxide particles 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.

[0042] Specifically, the ε-iron oxide containing additives is ε-Fe 2-x M x O3 crystal (wherein M 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. x is, for example, 0 <x<1である。)である。

[0043] (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 may have, for example, a cubic shape. In this specification, the cubic shape includes a substantially cubic shape. The Co-containing spinel ferrite may further contain at least one of Ni, Mn, Al, Cu, and Zn in addition to Co.

[0044] 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.)

[0045] (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, 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, and synthetic rubbers.

[0046] 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.

[0047] All of the above binders may contain -SO3M, -OSO3M, -COOM, P=O(OM)2 (where M represents a hydrogen atom or an alkali metal such as lithium, potassium, or sodium), -NR1R2, -NR1R2R3, etc., in order to improve the dispersibility of the magnetic powder. + X -A side chain amine having a terminal group represented by the formula: >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, an inorganic ion, or an organic ion.) Furthermore, polar functional groups such as -OH, -SH, -CN, and an epoxy group may 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.

[0048] (lubricant) The lubricant contains at least one selected from, for example, a fatty acid and a fatty acid ester, and preferably both a fatty acid and a fatty acid ester. The inclusion of a lubricant in magnetic layer 43, and particularly the inclusion of both a fatty acid and a fatty acid ester in magnetic layer 43, contributes to improving the running stability of magnetic tape MT.

[0049] 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).

[0050] 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 general formula (4).

[0051] 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 of the magnetic tape MT due to repeated recording or playback.

[0052] CH3(CH2) k COOH (1) (However, in general formula (1), k is an integer selected from the range of 14 or more and 22 or less, more preferably from the range of 14 or more and 18 or less.)

[0053] CH3(CH2) n CH=CH(CH2) m COOH (2) (However, in 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.)

[0054] CH3(CH2) p COO(CH2) q CH3···(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.)

[0055] 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.)

[0056] (antistatic agent) Examples of antistatic agents include carbon black, natural surfactants, nonionic surfactants, and cationic surfactants.

[0057] (abrasive) Examples of abrasives include acicular α-iron oxide obtained by dehydrating and annealing raw materials such as α-alumina with an α-conversion rate of 90% or more, 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, surface-treated with aluminum and / or silica.

[0058] (hardening 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.

[0059] (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.

[0060] (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).

[0061] (base layer) The underlayer 42 serves to reduce the unevenness of the surface of the substrate 41 and adjust the unevenness of the surface of the magnetic layer 43. The underlayer 42 is a non-magnetic layer containing non-magnetic powder, a binder, and a lubricant. The underlayer 42 supplies the lubricant to the surface of the magnetic layer 43. If necessary, the underlayer 42 may further contain at least one additive selected from the group consisting of an antistatic agent, a hardener, and an anti-rust agent.

[0062] The average thickness of the underlayer 42 is preferably 0.3 μm or more and 2.0 μm or less, and more preferably 0.5 μm or more and 1.4 μm or less. m The magnification of the TEM image is adjusted appropriately depending on the thickness of the underlayer 42. When the average thickness of the underlayer 42 is 2.0 μm or less, the magnetic tape MT becomes more elastic due to external forces, making it easier to adjust the width of the magnetic tape MT by adjusting the tension.

[0063] (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.

[0064] (binder, lubricant) The binder and lubricant are the same as those used in the magnetic layer 43 described above.

[0065] (additives) The antistatic agent, hardener, and anticorrosive agent are the same as those in the magnetic layer 43 described above.

[0066] (Back layer) The back layer 44 contains a binder and a non-magnetic powder. If necessary, the back layer 44 may further contain at least one additive selected from the group consisting of a lubricant, a hardener, and an antistatic agent. The binder and non-magnetic powder are the same as those of the underlayer 42 described above.

[0067] The upper limit of the average thickness of the back layer 44 is preferably 0.6 μm or less. If the upper limit of the average thickness of the back layer 44 is 0.6 μm or less, the thickness of the underlayer 42 and the substrate 41 can be kept thick even when the average thickness of the magnetic tape MT is 5.6 μm or less, thereby maintaining running stability of the magnetic tape MT within a recording / reproducing device. The lower limit of the average thickness of the back layer 44 is not particularly limited, but is, for example, 0.2 μm or more.

[0068] The average thickness t of the back layer 44 b can be calculated as follows: First, the average thickness t of the magnetic tape MT T Measure the average thickness t T The measurement method for is as described in "Average Thickness of Magnetic Tape" below. Next, the back layer 44 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 these measurements are simply averaged (arithmetic mean) to obtain the average thickness t B Then, the average thickness t of the back layer 44 is calculated using the following formula: b The measurement position is selected randomly from the sample. t b [μm]=t T [μm]-t B [μm]

[0069] (average thickness of magnetic tape) 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 5.6 μm or less, preferably 5.0 μm or less, more preferably 4.6 μm or less, and even more preferably 4.4 μm or less. TIf the average thickness t of the magnetic tape MT is 5.6 μm or less, the recording capacity that can be recorded in one data cartridge can be increased compared to that of a general magnetic tape. T The lower limit is not particularly limited, but is, for example, 3.5 μm or more.

[0070] Average thickness t of magnetic tape MT T is calculated 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 the measuring device, and the measured values ​​are simply averaged (arithmetic mean) to obtain the average thickness t T The measurement position is selected randomly from the sample.

[0071] (Coercive force) The upper limit of the coercive force Hc2 of the magnetic layer 43 in the longitudinal direction of the magnetic tape MT is preferably 2000 Oe or less, more preferably 1900 Oe or less, and even more preferably 1800 Oe or less. If the coercive force Hc2 of the magnetic layer 43 in the longitudinal direction is 2000 Oe or less, sufficient electromagnetic conversion characteristics can be obtained even at high recording densities.

[0072] The lower limit of the coercive force Hc2 of the magnetic layer 43 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 43 measured in the longitudinal direction is 1000 Oe or more, demagnetization due to leakage flux from the recording head can be suppressed.

[0073] The coercive force Hc2 is calculated as follows. First, three magnetic tapes MT are stacked with double-sided tape and then punched out with a 6.39 mm diameter punch to prepare a measurement sample. At this time, markings are made with any nonmagnetic ink so that the longitudinal direction (running direction) of the magnetic tape MT can be identified. Then, the MH 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 films (underlayer 42, magnetic layer 43, back layer 44, etc.) are wiped off using acetone or ethanol, leaving only the substrate 41. Three of the obtained substrates 41 are stacked with double-sided tape and then punched out with a 6.39 mm diameter punch to prepare a sample for background correction (hereinafter simply referred to as the "correction sample"). Thereafter, the MH loop of the correction sample (substrate 41) corresponding to the perpendicular direction of the substrate 41 (perpendicular direction of the magnetic tape MT) is measured using the VSM.

[0074] The MH loop of the measurement sample (the entire magnetic tape MT) and the MH loop of the correction sample (substrate 41) are measured using a high-sensitivity vibrating sample magnetometer, model VSM-P7-15, manufactured by Toei Kogyo 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.

[0075] After obtaining the MH loop of the measurement sample (the entire magnetic tape MT) and the MH loop of the correction sample (substrate 41), background correction is performed by subtracting the MH loop of the correction sample (substrate 41) from the MH loop of the measurement sample (the entire magnetic tape MT), resulting in the MH loop after background correction. 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 MH loop after background correction. Note that this calculation is performed using the measurement and analysis program included with the VSM-P7-15. Note that all of the above MH loop measurements are performed at 25°C. Furthermore, no "demagnetizing field correction" is performed when measuring the MH loop in the longitudinal direction of the magnetic tape MT.

[0076] (Square ratio) The squareness ratio S1 of the magnetic layer 43 in the perpendicular direction (thickness direction) of the magnetic tape MT is preferably 65% ​​or more, more preferably 70% or more, even more preferably 75% or more, particularly preferably 80% or more, and most preferably 85% or more. When the squareness ratio S1 is 65% or more, the perpendicular orientation of the magnetic powder is sufficiently high, resulting in even better electromagnetic conversion characteristics.

[0077] The squareness ratio S1 in the vertical direction is calculated as follows. First, three magnetic tapes MT are stacked with double-sided tape and then punched out with a 6.39 mm diameter punch to prepare a measurement sample. At this time, markings are made with any non-magnetic ink so that the longitudinal direction (running direction) of the magnetic tape MT can be identified. Then, the MH loop of the measurement sample (the entire magnetic tape MT) corresponding to the vertical direction (thickness direction) of the magnetic tape MT is measured using a VSM. Next, the coating film (underlayer 42, magnetic layer 43, back layer 44, etc.) is wiped off using acetone or ethanol, leaving only the substrate 41. Then, three obtained substrates 41 are stacked with double-sided tape and then punched out with a 6.39 mm diameter punch to prepare a sample for background correction (hereinafter simply referred to as the "correction sample"). Then, the MH loop of the correction sample (substrate 41) corresponding to the vertical direction of the substrate 41 (the vertical direction of the magnetic tape MT) is measured using a VSM.

[0078] The MH loop of the measurement sample (the entire magnetic tape MT) and the MH loop of the correction sample (substrate 41) are measured using a high-sensitivity vibrating sample magnetometer, model VSM-P7-15, manufactured by Toei Kogyo 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.

[0079] After obtaining the MH loop of the measurement sample (the entire magnetic tape MT) and the MH loop of the correction sample (substrate 41), background correction is performed by subtracting the MH loop of the correction sample (substrate 41) from the MH loop of the measurement sample (the entire magnetic tape MT), and the MH loop after background correction is obtained. This background correction calculation is performed using the measurement and analysis program included with the "VSM-P7-15 model."

[0080] The saturation magnetization Ms (emu) and residual magnetization Mr (emu) of the MH loop after background correction are substituted into the following equation to calculate the squareness ratio S1 (%). Note that all of the above MH loop measurements are performed at 25°C. Furthermore, no "demagnetizing field correction" is performed when measuring the MH 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

[0081] The squareness ratio S2 of the magnetic layer 43 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 magnetic powder has a sufficiently high perpendicular orientation, resulting in even better electromagnetic conversion characteristics.

[0082] 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 41.

[0083] (Coercive force ratio) The ratio Hc2 / Hc1 of the coercive force Hc1 of the magnetic layer 43 in the perpendicular direction to the coercive force Hc2 of the magnetic layer 43 in the longitudinal direction satisfies the relationship Hc2 / Hc1≦0.8, preferably Hc2 / Hc1≦0.75, more preferably Hc2 / Hc1≦0.7, even more preferably Hc2 / Hc1≦0.65, and particularly preferably Hc2 / Hc1≦0.6. When the coercive forces Hc1 and Hc2 satisfy the relationship Hc2 / Hc1≦0.8, the degree of perpendicular orientation of the magnetic powder can be enhanced. This reduces the magnetization transition width and enables high-output signals to be obtained during signal reproduction, resulting in even better electromagnetic conversion characteristics. As mentioned above, a small Hc2 allows the magnetization to respond more sensitively to the perpendicular magnetic field from the recording head, resulting in the formation of a good recording pattern.

[0084] When the ratio Hc2 / Hc1 is Hc2 / Hc1≦0.8, the average thickness t m It is particularly effective that the average thickness t of the magnetic layer 43 is 90 nm or less. m If the thickness exceeds 90 nm, when a ring-type head is used as the recording head, the lower region of the magnetic layer 43 (the region on the underlayer 42 side) may be magnetized in the longitudinal direction, which may prevent uniform magnetization of the magnetic layer 43 in the thickness direction. Therefore, even if the ratio Hc2 / Hc1 is Hc2 / Hc1≦0.8 (i.e., even if the degree of perpendicular orientation of the magnetic powder is increased), there is a risk that further excellent electromagnetic conversion characteristics may not be obtained.

[0085] The lower limit of Hc2 / Hc1 is not particularly limited, but is, for example, 0.5≦Hc2 / Hc1. Hc2 / Hc1 represents the degree of vertical orientation of the magnetic powder, and the smaller Hc2 / Hc1, the higher the degree of vertical orientation of the magnetic powder.

[0086] The method for calculating the coercive force Hc2 of the magnetic layer 43 in the longitudinal direction is as described above. The coercive force Hc1 of the magnetic layer 43 in the perpendicular direction is determined in the same manner as the coercive force Hc2 of the magnetic layer 43 in the longitudinal direction, except that the MH loop is measured in the perpendicular direction (thickness direction) of the magnetic tape MT and the substrate 41.

[0087] (Young's modulus in the longitudinal direction of magnetic tape) The Young's modulus of the magnetic tape MT in the longitudinal direction is preferably 8.0 GPa or less, more preferably 7.9 GPa or less, even more preferably 7.5 GPa or less, and particularly preferably 7.1 GPa or less. When the Young's modulus of the magnetic tape MT in the longitudinal direction is 8.0 GPa or less, the magnetic tape MT becomes more flexible due to external forces, making it easier to adjust the width of the magnetic tape MT by adjusting the tension. Therefore, off-track can be more appropriately suppressed, and data recorded on the magnetic tape MT can be reproduced more accurately.

[0088] The Young's modulus of the magnetic tape MT in the longitudinal direction is a value that indicates the resistance of the magnetic tape MT to expansion and contraction in the longitudinal direction due to external forces; the larger this value, the less the magnetic tape MT is able to expand and contract in the longitudinal direction due to external forces; the smaller this value, the more easily the magnetic tape MT is able to expand and contract in the longitudinal direction due to external forces.

[0089] The Young's modulus in the longitudinal direction of the magnetic tape MT is a value related to the longitudinal direction of the magnetic tape MT, but it also correlates with the resistance to expansion and contraction in the width direction of the magnetic tape MT. In other words, the larger this value, the less the magnetic tape MT is susceptible to expansion and contraction in the width direction due to external forces, and the smaller this value, the more the magnetic tape MT is susceptible to expansion and contraction in the width direction due to external forces. Therefore, from the perspective of tension adjustment, a smaller Young's modulus in the longitudinal direction of the magnetic tape MT is advantageous.

[0090] A tensile tester (AG-100D, manufactured by Shimadzu Corporation) is used to measure Young's modulus. If you want to measure Young's modulus in the longitudinal direction of the tape, cut the tape to a length of 180 mm to prepare a measurement sample. A jig that can fix the width of the tape (1 / 2 inch) is attached to the tensile tester, and the top and bottom of the tape width are fixed. The distance (length of the tape between the chucks) is set to 100 mm. After chucking the tape sample, stress is gradually applied in the direction of pulling the sample. The pulling speed is 0.1 mm / min. From the change in stress and the amount of elongation at this time, Young's modulus is calculated using the following formula. E(N / m 2 )=((ΔN / S) / (Δx / L))×10 6 ΔN: Change in stress (N) S: Cross-sectional area of ​​the test piece (mm 2 ) Δx: Elongation (mm) L: Distance between gripping jigs (mm) The stress range is set to 0.5N to 1.0N, and the change in stress (ΔN) and the amount of elongation (Δx) at this time are used in the calculation.

[0091] (Young's modulus in the longitudinal direction of the substrate) The Young's modulus of the substrate 41 in the longitudinal direction is preferably 7.5 GPa or less, more preferably 7.4 GPa or less, even more preferably 7.0 GPa or less, and particularly preferably 6.6 GPa or less. When the Young's modulus of the substrate 41 in the longitudinal direction is 7.5 GPa or less, the magnetic tape MT becomes more flexible due to external forces, making it easier to adjust the width of the magnetic tape MT by adjusting the tension. Therefore, off-track can be more appropriately suppressed, and data recorded on the magnetic tape MT can be reproduced more accurately.

[0092] The Young's modulus in the longitudinal direction of the substrate 41 is determined as follows: First, the underlayer 42, the magnetic layer 43, and the back layer 44 are removed from the magnetic tape MT to obtain the substrate 41. Using this substrate 41, the Young's modulus in the longitudinal direction of the substrate 41 is determined in the same manner as for the Young's modulus in the longitudinal direction of the magnetic tape MT.

[0093] The thickness of the substrate 41 accounts for more than half of the total thickness of the magnetic tape MT. Therefore, the Young's modulus in the longitudinal direction of the substrate 41 correlates with the resistance of the magnetic tape MT to expansion and contraction due to external forces, and the larger this value, the less the magnetic tape MT is able to expand and contract in the width direction due to external forces, and the smaller this value, the more the magnetic tape MT is able to expand and contract in the width direction due to external forces.

[0094] The Young's modulus of the substrate 41 in the longitudinal direction is a value related to the longitudinal direction of the magnetic tape MT, but it also correlates with the resistance of the magnetic tape MT to expansion and contraction in the width direction. In other words, the larger this value, the less the magnetic tape MT will expand and contract in the width direction due to external force, and the smaller this value, the more the magnetic tape MT will expand and contract in the width direction due to external force. Therefore, from the perspective of tension adjustment, it is advantageous for the substrate 41 to have a smaller Young's modulus in the longitudinal direction.

[0095] [3 Magnetic Tape Format] 3 is a schematic diagram showing an example of the layout of data bands and servo bands. The magnetic tape MT (specifically, the magnetic layer 43) already has a plurality of servo bands SB and a plurality of data bands DB. The plurality of servo bands SB are provided at equal intervals in the width direction of the magnetic tape MT. A data band DB is provided between adjacent servo bands SB. The servo bands SB are used to guide the magnetic head 51 (specifically, servo read heads 51A and 51B) of the recording / reproducing device (drive) when recording or reproducing data. A servo pattern (servo signal) for tracking control of the magnetic head 51 is written in advance in the servo bands SB. User data is recorded in the data bands DB.

[0096] The total area S of the plurality of servo bands SB relative to the surface area S of the magnetic layer 43 SB The ratio R S (=(S SB From the viewpoint of ensuring a high recording capacity, the upper limit of the ratio (S / S)×100) is preferably 4.0% or less, more preferably 3.0% or less, and even more preferably 2.0% or less. SB The ratio R S The lower limit of is preferably 0.8% or more from the viewpoint of ensuring 5 or more servo bands SB.

[0097] The total area S of the plurality of servo bands SB relative to the area S of the entire surface of the magnetic layer 43 SB The ratio RS of the servo band width W is calculated as follows: The magnetic tape MT is developed using a ferricolloid developer (Sigma Marker Q, manufactured by Sigma High Chemical Co., Ltd.), and the developed magnetic tape MT is then observed under an optical microscope. SB and the number of servo bands SB. Next, calculate the ratio R from the following formula: S Ask for. Ratio R S [%]=(((Servo bandwidth W SB ) x (number of servo bands SB)) / (width of magnetic tape MT)) x 100

[0098] The number of servo bands SB is preferably 5 or more, more preferably 5+4n (where n is a positive integer) or more. If the number of servo bands SB is 5 or more, the effect on the servo signal due to dimensional changes in the width direction of the magnetic tape MT can be suppressed, ensuring stable recording and reproduction characteristics with less off-track. The upper limit of the number of servo bands SB is not particularly limited, but is, for example, 33 or less.

[0099] The number of servo bands SB is calculated in the same manner as the ratio RS is calculated above.

[0100] Servo Bandwidth W SB From the viewpoint of ensuring a high recording capacity, the upper limit of the servo bandwidth W is preferably 99 μm or less, more preferably 60 μm or less, and even more preferably 30 μm or less. SB The lower limit is preferably 10 μm or more.

[0101] Servo Bandwidth W SB The width is calculated in the same manner as the ratio RS above.

[0102] 4 is an enlarged view showing an example of the configuration of a data band. The magnetic layer 43 is configured so that multiple data tracks Tk can be formed on the data band DB. From the viewpoint of improving track recording density and ensuring high recording capacity, the upper limit of the data track width W is preferably 2000 nm or less, more preferably 1500 nm or less, and even more preferably 1000 nm. Taking into account the magnetic particle size, the lower limit of the data track width W is preferably 20 nm or more.

[0103] To ensure a high recording capacity, the magnetic layer 43 is configured to record data such that the minimum distance L between magnetization reversals is preferably 48 nm or less, more preferably 44 nm or less, and even more preferably 40 nm or less. Taking the magnetic grain size into consideration, the lower limit of the minimum distance L between magnetization reversals is preferably 20 nm or more.

[0104] The magnetic layer 43 is configured to record data such that the minimum distance between magnetization reversals L and the data track width W are preferably W / L≦35, more preferably W / L≦30, and even more preferably W / L≦25. If the minimum distance between magnetization reversals L is a constant value and the minimum distance between magnetization reversals L and the track width W are W / L>35 (i.e., if the track width W is large), the track recording density does not increase, and there is a risk that sufficient recording capacity cannot be ensured. Also, if the track width W is a constant value and the minimum distance between magnetization reversals L and the track width W are W / L>35 (i.e., if the minimum distance between magnetization reversals L is small), the bit length decreases and the linear recording density increases, but there is a risk that the electromagnetic conversion characteristics may deteriorate significantly due to the effects of spacing loss. Therefore, to prevent deterioration of the electromagnetic conversion characteristics while ensuring the recording capacity, it is preferable that W / L be in the range of W / L≦35, as described above. The lower limit of W / L is not particularly limited, but is, for example, 1≦W / L.

[0105] The data track width W is calculated as follows. A magnetic tape MT with data recorded all over its surface is prepared, and the data recording pattern in the data band DB portion of its magnetic layer 43 is observed using a magnetic force microscope (MFM) to obtain an MFM image. 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. MFM measurements are performed on three 10 μm × 10 μm measurement areas in different locations, resulting in three MFM images. From the three MFM images obtained, the track width is measured at 10 locations using the analysis software included with the Dimension3100, and the average (simple average) is calculated. This average value is the data track width W. The measurement conditions for the MFM were: sweep rate: 1 Hz, tip used: MFMR-20, lift height: 20 nm, and correction: Flatten order 3.

[0106] The minimum distance L between magnetic reversals is calculated as follows. A magnetic tape MT with data recorded on its entire surface is prepared, and the data recording pattern in the data band DB portion of its magnetic layer 43 is observed using a magnetic force microscope (MFM) to obtain an MFM image. The MFM uses a Digital Instruments Dimension3100 and its analysis software. The measurement area of ​​the MFM image is 2 μm × 2 μm, and this 2 μm × 2 μm measurement area is divided into 512 × 512 (= 262,144) measurement points. MFM measurements are performed on three 2 μm × 2 μm measurement areas in different locations, resulting in three MFM images. Fifty inter-bit distances are measured from a two-dimensional concavo-convex chart of the recording pattern in the obtained MFM image. The inter-bit distances are measured using the analysis software provided with the Dimension3100. The minimum value L of the inter-magnetic reversal distance is determined to be the greatest common divisor of the 50 measured inter-bit distances. The measurement conditions were: sweep speed: 1 Hz, tip used: MFMR-20, lift height: 20 nm, and correction: Flatten order 3.

[0107] The servo patterns are magnetized regions, and are formed by magnetizing specific regions of the magnetic layer 43 in a specific direction using a servo writer during magnetic tape manufacturing. The regions of the servo bands SB where no servo patterns are formed (hereinafter referred to as "non-pattern regions") may be magnetized regions where the magnetic layer 43 is magnetized, or may be non-magnetized regions where the magnetic layer 43 is not magnetized. When the non-pattern regions are magnetized regions, the servo pattern forming regions and the non-pattern regions may be magnetized in different directions (e.g., opposite directions). The servo patterns (servo signals) have LPOS (Longitudinal Position Of Signal) information embedded in them. The LPOS information indicates the longitudinal position of the magnetic tape MT and is longitudinal position information for uniquely identifying each servo band SB.

[0108] 5 is an enlarged view showing an example of the configuration of the servo band SB. In the LTO standard, the servo band SB has a servo pattern formed thereon, which is made up of a plurality of servo stripes (linear magnetized regions) 113 that are inclined with respect to the width direction of the magnetic tape MT.

[0109] The servo band SB includes a plurality of servo frames 110. Each servo frame 110 is made up of 18 servo stripes 113. Specifically, each servo frame 110 is made up of a servo subframe 1 (111) and a servo subframe 2 (112).

[0110] Servo subframe 1 (111) is composed of an A burst 111A and a B burst 111B. The B burst 111B is located adjacent to the A burst 111A. The A burst 111A has five servo stripes 113 formed at regular intervals and inclined at a predetermined angle φ with respect to the width direction of the magnetic tape MT. In FIG. 5, these five servo stripes 113 are denoted by symbols A1, A2, A3, A4, and A5 from the EOT (End of Tape) to the BOT (Beginning of Tape) of the magnetic tape MT. Like the A burst 111A, the B burst 111B has five servo stripes 113 formed at regular intervals and inclined at a predetermined angle φ with respect to the width direction of the magnetic tape MT. In FIG. 5, these five servo stripes 113 are denoted by symbols B1, B2, B3, B4, and B5 from the EOT to the BOT of the magnetic tape MT. The servo stripes 113 of the B burst 111B are inclined in the opposite direction to the servo stripes 113 of the A burst 111A. That is, the servo stripes 113 of the A burst 111A and the servo stripes 113 of the B burst 111B are arranged in a V-shape.

[0111] Servo subframe 2 (112) is composed of a C burst 112C and a D burst 112D. The D burst 112D is located adjacent to the C burst 112C. The C burst 112C has four servo stripes 113 that are inclined at a predetermined angle φ with respect to the tape width direction and spaced at regular intervals. In FIG. 5, these four servo stripes 113 are denoted by symbols C1, C2, C3, and C4 from the EOT to the BOT of the magnetic tape MT. Like the C burst 112C, the D burst 112D also has four servo stripes 113 that are inclined at a predetermined angle φ with respect to the tape width direction and spaced at regular intervals. In FIG. 5, these four servo stripes 113 are denoted by symbols D1, D2, D3, and D4 from the EOT to the BOT of the magnetic tape MT. The servo stripes 113 of the D burst 112D are inclined in the opposite direction to the servo stripes 113 of the C burst 112C. That is, the servo stripes 113 of the C burst 112C and the servo stripes 113 of the D burst 112D are arranged in a V-shape.

[0112] The predetermined angle φ of the servo stripes 113 in the A burst 111A, B burst 111B, C burst 112C, and D burst 112D can be, for example, 5° to 25°, and particularly 11° to 25°.

[0113] Reading the servo band SB with the magnetic head 51 provides information for determining the tape speed and the longitudinal position of the magnetic head. The tape speed is calculated from the times between four timing signals (A1-C1, A2-C2, A3-C3, A4-C4). The head position is calculated from the times between the aforementioned four timing signals and another four timing signals (A1-B1, A2-B2, A3-B3, A4-B4).

[0114] 5, the servo patterns (i.e., the plurality of servo stripes 113) are preferably arranged linearly in the longitudinal direction of the magnetic tape MT. That is, the servo bands SB preferably have a linear shape in the longitudinal direction.

[0115] FIG. 6 is a schematic diagram showing an example of the format of a magnetic tape MT. The magnetic tape MT is divided into seven regions in the longitudinal direction by eight logical points LP0 to LP7. LP0 to LP7 are set in this order from one end of the magnetic tape MT at the end of winding to the other end at the beginning of winding. The magnetic tape MT is also divided into five or more servo bands and four or more data bands in the width direction. Note that FIG. 6 shows an example in which the magnetic tape MT is divided into five servo bands and four data bands in the width direction.

[0116] The seven areas are: unused area (area between LP0 and LP1) R1, forward servo recognition area (area between LP1 and LP2) R2, calibration area (area between LP2 and LP3) R3, user data area (area between LP3 and LP4) R4, unused data area (area between LP4 and LP5) R5, reverse servo recognition area (area between LP5 and LP6) R6, and unused area (area between LP6 and LP7) R7. In the following description, the servo recognition area R2, calibration area R3, user data area R4, unused data area R5, and reverse servo recognition area R6 may be collectively referred to as used areas.

[0117] In this specification, the "forward direction" refers to the running direction of the magnetic tape MT when it is fed out of the cartridge 10 and wound up by a reel of a servo writer, etc. The "reverse direction" refers to the running direction of the magnetic tape MT when it is fed out of a reel of a servo writer, etc. and wound up into the cartridge 10.

[0118] A servo pattern that satisfies the standard is formed in the used area. The servo pattern that satisfies the standard is formed by the distance D between the A burst 111A and the C burst 112C. AC and the distance D between C burst 112C and A burst 111A CAmeets the standard. In this case, as shown in Figure 7A, the ends of B burst 111B and C burst 112C are separated from each other, and the ends of D burst 112D and A burst 111A are separated from each other. This forms a V-shaped servo pattern. The servo pattern shown in Figure 5 is an example of a servo pattern formed in a usable area that meets the standard.

[0119] Both unused area R1 and unused area R7 have servo patterns that do not meet the specifications. The servo patterns that do not meet the specifications may be formed in part of unused area R1 or in the entirety of unused area R1. Similarly, the servo patterns that do not meet the specifications may be formed in part of unused area R7 or in the entirety of unused area R7. As described above, unused area R1 is provided at the end of the magnetic tape MT on the winding end side, and unused area R7 is provided at the end of the magnetic tape MT on the winding start side.

[0120] A servo pattern that does not meet the standard is, for example, the distance D between A burst 111A and C burst 112C. AC and the distance D between C burst 112C and A burst 111A CA is narrower than the standard or wider than the standard.

[0121] When the magnetic tape MT is traveling in the forward direction, the unused area R1 is an area where the magnetic tape MT is traveling at an accelerated speed. Therefore, when the servo signal is written by the same control as in the used area, the distance D between the A burst 111A and the C burst 112C becomes AC and the distance D between C burst 112C and A burst 111A CA is narrower than the standard.

[0122] When the magnetic tape MT is running in the forward direction, the unused area R7 is an area where the magnetic tape MT is decelerated. Therefore, when the servo signal is written by the same control as in the used area, the distance D between the A burst 111A and the C burst 112C is AC and the distance D between C burst 112C and A burst 111A CAis narrower than the standard.

[0123] Distance D AC and distance D CA 7B, for example, the ends of B burst 111B and C burst 112C overlap, forming a V-shaped servo pattern together. Also, the ends of D burst 112D and A burst 111A overlap, forming a V-shaped servo pattern together.

[0124] Distance D AC and distance D CA 7C, for example, when B burst 111B and C burst 112C intersect, an X-shaped servo pattern is formed by B burst 111B and C burst 112C. Also, when D burst 112D and A burst 111A intersect, an X-shaped servo pattern is formed by D burst 112D and A burst 111A.

[0125] Whether or not non-compliant servo patterns are formed in unused areas R1 and R7 can be confirmed as follows. First, the cartridge 10 is disassembled and the magnetic tape MT is removed. Next, the servo patterns (i.e., servo bands SB) formed on the magnetic layer 43 of the removed magnetic tape MT in unused areas R1 and R7 are observed using a magnetic force microscope (MFM) to obtain MFM images. A Digital Instruments Dimension3100 and its analysis software are used as the MFM. Next, it is confirmed whether or not the servo patterns in the obtained MFM images meet the standards. Alternatively, after applying a ferricolloid developer (Sigma Marker Q, manufactured by Sigma High Chemical Co., Ltd.), confirmation can also be performed using a microscope at approximately 100 to 1000 magnifications.

[0126] In conventional cartridges, servo signals that meet the standard are written in the unused areas at the beginning and end of the tape. This is because, in the manufacturing process of conventional cartridges, magnetic tape on which servo patterns that meet the standard are written from one end of the tape to the other in the longitudinal direction is assembled into the cartridge, and no processing is performed to rewrite the servo signals after assembly.

[0127] [4. Servo writer configuration for cartridges] 8 is a schematic diagram showing an example of the configuration of a cartridge servo writer 210. The servo writer 210 erases the servo signals written in the cartridge 10 and rewrites the servo signals. By rewriting the servo signals, non-compliant servo patterns (second servo patterns) are formed in the unused areas R1 and R7.

[0128] The servo writer 210 includes a cartridge storage section 211, a reel 212, guide rollers 213A, 213B, 213C, and 213D, a degaussing magnet 214, a servo signal writing head 215, a verify head 216, a control device 217, a pulse generating circuit 218, a spindle driving circuit 219A, a reel driving circuit 219B, and an operation section (not shown).

[0129] A running section is formed by the cartridge housing section 211, the reel 212, and the guide rollers 213A, 213B, 213C, and 213D. When writing a servo signal, this running section feeds out the magnetic tape MT in the form of a tape from the cartridge 10 and reels it up onto the reel 212, thereby running the magnetic tape MT in the forward direction. After writing the servo signal, this running section feeds out the magnetic tape MT in the form of a tape from the reel 212 and reels it up onto the cartridge 10, thereby running the magnetic tape MT in the reverse direction. In the following description, the term "running path" refers to the path along which the magnetic tape MT runs in the servo writer 210. Additionally, the terms "upstream side" and "downstream side" refer to the upstream and downstream sides of the running path when the magnetic tape MT runs in the forward direction.

[0130] (Cartridge storage section) The cartridge accommodating section 211 is configured to be able to accommodate the cartridge 10. The cartridge accommodating section 211 is provided with a loading mechanism (not shown) and is configured to be able to load the cartridge 10. The cartridge accommodating section 211 feeds out the magnetic tape MT onto which the servo signal is rewritten. The cartridge accommodating section 211 is provided with a spindle 241A. The spindle 241A is configured to be able to mount the cartridge 10. The magnetic tape MT is fed out by the rotation of the spindle 241A.

[0131] (reel) The reel 212 winds up the magnetic tape MT on which the servo signals have been rewritten. The reel 212 is configured so that the leading end (leader pin 20) of the magnetic tape MT pulled out from the cartridge 10 can be fixed.

[0132] (Guide roller) The guide rollers 213A and 213B are provided on a running path between the cartridge receiving portion 211 and the servo signal write head 215. The guide rollers 243A and 243B guide the magnetic tape MT running from the cartridge receiving portion 211 toward the servo signal write head 215. The guide rollers 243C and 243D are provided on a running path between the servo signal write head 215 and the reel 212. The guide rollers 243C and 243D guide the magnetic tape MT running from the servo signal write head 215 toward the reel 212.

[0133] (degaussing magnet) The demagnetizing magnet 214 is provided upstream of the servo signal write head 215 in the travel path. The demagnetizing magnet 214 erases the servo pattern (first servo pattern) formed on the magnetic tape MT traveling in the forward direction. The demagnetizing magnet 214 may be rotatable as disclosed in JP 2018-005970 A, and may be a magnet that can change the magnetic field applied to the magnetic layer 43 in response to the rotation.

[0134] (Servo signal writing head) The servo signal write head 215 is a magnetic head for rewriting a servo signal onto the magnetic tape running in the forward direction from which the servo pattern has been erased, to form a servo pattern (second servo pattern). As the servo signal write head 215, for example, the one described in Patent Document 1 can be used.

[0135] The servo signal write head 215 has a sliding surface that slides against the magnetic tape MT. The servo signal write head 215 has five or more recording elements and at least one bottomed cavity (recess) on the sliding surface. The recording elements have magnetic gaps. The multiple magnetic gaps are arranged in a row on the sliding surface at a predetermined distance apart so as to correspond to the positions of each servo band in the width direction of the magnetic tape MT. The five or more recording elements each write a servo signal to the magnetic tape MT, thereby forming five or more servo bands SB.

[0136] The bottomed cavity is closed and is formed only within the width of the magnetic tape MT running area. By providing a bottomed cavity with this configuration on the sliding surface, the expansion of air between the sliding surface and the magnetic tape MT is promoted when the magnetic tape MT runs, and the air pressure drops, i.e., negative pressure, thereby reducing spacing and improving the running stability of the magnetic tape MT.

[0137] (Verify Head) The verify head 216 is provided downstream of the travel path of the servo signal write head 215. The verify head 216 is a magnetic head that comes into sliding contact with the magnetic tape MT, on which servo signals are written, traveling in the forward direction, and reads the servo signals written on the servo bands SB. The verify head 216 can have a configuration similar to that of the servo signal write head 215, except that it includes a plurality of reproducing elements instead of a plurality of recording elements.

[0138] (Control device) The control device 217 controls the operation of each part of the servo writer 210 and includes a CPU (Central Processing Unit), various storage devices, etc. The control device 217 controls the servo signal write head 215 to write servo signals during acceleration and deceleration periods of the magnetic tape MT, thereby forming servo patterns on the magnetic tape MT that do not meet the standards. The control device 217 controls the servo signal write head 215 to write servo signals during constant speed periods of the magnetic tape MT, thereby forming servo patterns on the magnetic tape MT that meet the standards.

[0139] The control device 217 generates a pulse control signal for controlling the current value, pulse width, and generation timing of the recording pulse current so that the servo signal written onto the magnetic tape MT by the servo signal write head 215 becomes a specified servo pattern, and supplies the signal to the pulse generation circuit 218.

[0140] The control device 217 checks whether the servo signals are properly recorded on the magnetic tape MT based on the servo signals supplied from the verify head 216. Specifically, the control device 217 stores information about servo signals that meet standards (hereinafter referred to as "standard information") in a storage device, compares this standard information with the servo signals supplied from the verify head 216, and checks whether the servo signals are properly recorded on the magnetic tape MT.

[0141] The control device 217 erases the servo signals written on the magnetic tape MT by moving the degaussing magnet 214 and bringing it into contact with the magnetic tape MT.

[0142] The control device 217 controls the spindle drive circuit 219A to rotate the spindle 211A. The control device 217 controls the reel drive circuit 219B to rotate the reel 212. Specifically, the control device 217 generates motor current signals for controlling the motor currents of the spindle drive circuit 219A and the reel drive circuit 219B to control the running speed of the magnetic tape MT when writing servo signals, and supplies these signals to the spindle drive circuit 219A and the reel drive circuit 219B.

[0143] (Operation unit) The operation unit is used to operate the servo writer 210 and execute servo writing operations, etc. The operation unit is connected to the control device 217.

[0144] (Pulse generation circuit) The pulse generating circuit 218 generates a recording pulse current based on the pulse control signal supplied from the control device 217 and supplies it to the servo signal write head 215 .

[0145] (Spindle drive circuit) Spindle drive circuit 219A rotates spindle 211A under the control of control device 217. Spindle drive circuit 219A is a device for driving spindle 211A to rotate, and includes a motor integrated with spindle 211A, a motor drive circuit for supplying current to the motor, etc. In spindle drive circuit 219A, a motor current is generated by the motor drive circuit based on a motor current signal supplied from control device 217, and this motor current is supplied to the motor to drive spindle 211A to rotate.

[0146] (reel drive circuit) The reel drive circuit 219B rotates the reel 212 under the control of the control device 217. The reel drive circuit 219B is a device for driving the reel 212 to rotate, and includes a motor, a motor drive circuit for supplying current to the motor, and gears for connecting the motor shaft to the reel 212. In the reel drive circuit 219B, a motor current is generated by the motor drive circuit based on a motor current signal supplied from the control device 217, and by supplying this motor current to the motor, the rotational drive force of the motor is transmitted to the reel 212 via the gears, driving the reel 212 to rotate.

[0147] [5. Operation of the cartridge servo writer] An example of the operation of the servo writer 210 having the above configuration will now be described.

[0148] First, an operator loads the cartridge 10 into the cartridge storage section 211. After loading, the operator pulls out the magnetic tape MT from the cartridge 10 and fixes its tip (leader pin 20) to the reel 212. Note that the cartridge 10 stored in the cartridge storage section 211 may be one whose magnetic tape MT has been confirmed to be of poor quality.

[0149] Next, when the operator operates an operating unit (not shown), the control device 217 brings the degaussing magnet 214 into contact with the magnetic tape MT. The control device 217 controls the rotation of the spindle 211A and the reel 212 via the spindle drive circuit 219A and the reel drive circuit 219B, feeds out the magnetic tape from the cartridge 10, and takes up the fed magnetic tape MT by the reel 212. This causes the magnetic tape MT to accelerate and run in the forward direction. The degaussing magnet 214 erases the servo pattern (i.e., the servo signal written on the magnetic tape MT) formed on the magnetic tape MT running in the forward direction.

[0150] Next, during the accelerating running period of the magnetic tape MT, the control device 217 erases the servo patterns (i.e., servo signals written on the magnetic tape MT) formed in the unused area R1 of the magnetic tape MT running in the forward direction using the degaussing magnet 214. Next, during the accelerating running period of the magnetic tape MT, the control device 217 controls the servo signal write head 215 to write servo signals, and forms servo patterns that do not meet the standard in the unused area R1 of the magnetic tape running in the forward direction.

[0151] Next, when the running speed of the magnetic tape MT reaches a specified running speed, the control device 217 controls the rotation of the spindle 211A and the reel 212 via the spindle drive circuit 219A and the reel drive circuit 219B, causing the magnetic tape MT to run in the forward direction at a specified constant speed.

[0152] Next, during the period in which the magnetic tape MT is traveling at a constant speed, the control device 217 erases the servo patterns (i.e., the servo signals written on the magnetic tape MT) formed in the used areas of the magnetic tape MT traveling in the forward direction using the degaussing magnet 214. Next, during the period in which the magnetic tape MT is traveling at a constant speed, the control device 217 rewrites the servo signals in the used areas of the magnetic tape MT traveling in the forward direction using the servo signal write head 215, thereby forming servo patterns that meet the standard. The servo signals include LPOS information, and when the servo signals are rewritten, the LPOS information is also written to the servo band SB.

[0153] Next, during the period in which the magnetic tape MT is running at a constant speed, the control device 217 uses the verify head 216 to read servo signals from the magnetic tape MT running in the forward direction, and based on the read servo signals, checks whether the servo signals have been written properly.

[0154] Next, when the specified length of magnetic tape MT has been wound onto cartridge 10, control device 217 controls the rotation of spindle 211A and reel 212 via spindle drive circuit 219A and reel drive circuit 219B, causing magnetic tape MT to run forward at a slower speed.

[0155] Next, during the deceleration period of the magnetic tape MT, the control device 217 erases the servo patterns (i.e., servo signals written on the magnetic tape MT) formed in the unused area R7 of the magnetic tape MT running in the forward direction using the degaussing magnet 214. Next, during the deceleration period of the magnetic tape MT, the control device 217 controls the servo signal write head 215 to write servo signals, and forms servo patterns that do not meet the standard in the unused area R7 of the magnetic tape running in the forward direction.

[0156] Next, when all of the magnetic tape MT stored in the cartridge 10 has been fed out, the control device 217 stops the rotation of the spindle 211A and the reel 212 via the spindle drive circuit 219A and the reel drive circuit 219B. This stops the running of the magnetic tape MT. Next, the control device 217 stops the degaussing function by moving the degaussing magnet 214 away from the magnetic tape MT. Next, the control device 217 controls the rotation of the spindle 211A and the reel 212 via the spindle drive circuit 219A and the reel drive circuit 219B, feeds out the magnetic tape MT from the reel 212, and takes up the fed magnetic tape MT by the cartridge 10.

[0157] Next, when the magnetic tape MT wound around the reel 212 has been completely fed out and wound onto the cartridge 10, the control device 217 stops the rotation of the spindle 211A and the reel 212 via the spindle drive circuit 219A and the reel drive circuit 219B. Thereafter, the control device 217 unloads the cartridge 10 from the cartridge storage section 211 in response to the operation of the operation section.

[0158] [6. Servo signal recording system configuration] 9 is a schematic diagram showing an example of the configuration of a servo signal recording system. The servo signal recording system includes a pancake servo writer 220, a winder 230, a quality inspection device 240, and a cartridge servo writer 210. Here, "pancake" refers to magnetic tape MT wound in a roll (a wound body of magnetic tape MT) before being cut to a specified length.

[0159] The servo writer 210 for cartridges has been described above, so the servo writer 210 for pancakes, the winder 230, and the quality inspection device 240 will be described below.

[0160] (Pancake Servo Writer) 10 is a schematic diagram showing an example of the configuration of a pancake servo writer 220. The servo writer 220 is configured to be able to write servo signals onto a magnetic tape MT serving as a pancake.

[0161] The servo writer 220 includes reels 221 and 212, guide rollers 213A, 213B, 213C, and 213D, a degaussing magnet 214, a servo signal write head 215, a verify head 216, a control device 222, a pulse generating circuit 218, reel drive circuits 219C and 219B, and an operation unit (not shown). Note that parts of the servo writer 220 that are the same as those of the servo writer 210 are designated by the same reference numerals, and their description will be omitted.

[0162] The reel 221 is configured to be able to accommodate a pancake magnetic tape MT, and delivers the magnetic tape MT onto which servo signals are written.

[0163] The control device 222 controls the rotation of the reels 212 via the reel drive circuits 219C and 219B, causing the magnetic tape MT to run in the forward direction at a predetermined constant speed. The control device 222 may control the servo signal write head 215 not to write servo signals during the acceleration and deceleration running periods of the magnetic tape MT, or may control the servo signal write head 215 to write servo signals. However, unlike the control device 217, the control device 222 does not have the function of running the magnetic tape MT in the reverse direction.

[0164] The operation unit is used to operate the servo writer 220 and execute servo writing operations, etc. The operation unit is connected to the control device 222.

[0165] (winder) 11 is a schematic diagram showing an example of the configuration of the winder 230. The winder 230 loads the magnetic tape MT, on which servo signals are written, into the cartridge case 12. The winder 230 includes a reel 231, a guide roller 232, a cartridge storage section 211, a control device 233, a spindle drive circuit 219A, and an operation section (not shown). Note that parts of the winder 230 that are the same as those of the servo writer 210 are given the same reference numerals, and their description will be omitted.

[0166] The reel 231 is configured to be able to accommodate a pancake magnetic tape MT on which servo signals are written. The reel 231 feeds out the magnetic tape MT onto which the servo signals are written. A guide roller 232 is provided on a running path between the reel 231 and the cartridge accommodating section 211. The guide roller 232 guides the magnetic tape MT running from the reel 231 toward the cartridge accommodating section 211. The control device 233 controls the spindle drive circuit 219A to rotate the spindle 211A. This causes the magnetic tape MT to be fed out from the reel 231, and the fed magnetic tape MT is taken up by the cartridge 10.

[0167] The operating unit is used to operate the winder 230 and perform operations such as winding up the magnetic tape MT. The operating unit is connected to the control device 233.

[0168] (Quality inspection equipment) The quality inspection device 240 inspects the quality of the servo signal of the magnetic tape MT incorporated in the cartridge case 12. Poor quality of the servo signal includes, for example, a missing servo signal, poor servo tracking characteristics, and the like.

[0169] [7 Operation of servo signal recording system] An example of the operation of the servo signal recording system having the above configuration will now be described.

[0170] (Servo signal writing process) Servo signals are written to the magnetic tape MT cut to a specified width using the servo writer 220 as follows: First, an operator loads the magnetic tape MT as a pancake onto the reel 221, pulls out the outermost end of the magnetic tape MT, and fixes it to the reel 212. Next, when the operator operates an operating unit (not shown), the control device 222 controls the rotation of the reel 212 via the reel drive circuit 219B, unwinds the magnetic tape MT from the cartridge 10, and takes up the unwound magnetic tape MT by the reel 212. This causes the magnetic tape MT to run in the forward direction.

[0171] Next, the control device 222 erases the magnetic tape MT running in the forward direction using a degaussing magnet 214, and then writes servo signals onto the magnetic tape MT running in the forward direction using a servo signal write head 215 to form a servo pattern. Next, the control device 222 reads the written servo signals from the magnetic tape MT running in the forward direction using a verify head 216, and checks whether the servo signals have been written properly based on the read servo signals.

[0172] Next, when all of the pancake magnetic tape MT has been fed out, the control device 222 stops the rotation of the reel 212 via the reel drive circuit 219B. This stops the transport of the magnetic tape MT. Thereafter, the operator removes the pancake magnetic tape MT with the servo signals written thereto from the reel 212 and transports it to the winder 230.

[0173] (Assembly process) The magnetic tape MT on which servo signals are written is assembled into the cartridge 10 using the winder 230 as follows: First, an operator mounts the magnetic tape MT as a pancake onto the reel 231, and then loads the cartridge 10 into the cartridge accommodating section 211. Next, the leading end of the magnetic tape MT mounted on the reel 231 on the outer periphery is pulled out and fixed to the reel 13 (see FIG. 1) of the cartridge 10.

[0174] Next, when the operator operates the operating unit (not shown), the control device 233 controls the rotational drive of the spindle 211A via the spindle drive circuit 219A, feeds out the magnetic tape MT from the reel 231, and winds up the fed magnetic tape MT into the cartridge 10.

[0175] Next, when a specified length of magnetic tape has been wound onto the cartridge 10, the control device 233 stops the rotation of the spindle 211A via the spindle drive circuit 219A. This stops the transport of the magnetic tape MT. Thereafter, the control device 233 unloads the cartridge 10 from the cartridge storage unit 211 in response to the operation of the operating unit. The unloaded cartridge 10 is transported to the quality inspection device 240 by an operator.

[0176] If non-standard servo patterns are formed in portions within a predetermined range from both ends of the pancake magnetic tape MT in the longitudinal direction, these portions may be cut off and removed from the magnetic tape MT in this assembly process. Alternatively, if no servo patterns are formed in portions within a predetermined range from both ends of the pancake magnetic tape MT in the longitudinal direction, these portions may be cut off and removed from the magnetic tape MT in this assembly process.

[0177] (Quality inspection process) The quality of the servo signal of the magnetic tape MT incorporated in the cartridge 10 is inspected using the quality inspection device 240. If the inspection reveals no quality defects in the magnetic tape MT, the cartridge 10 is shipped. On the other hand, if the inspection reveals a quality defect in the magnetic tape MT, the cartridge 10 is transported to the servo writer 210. Then, in a "servo signal rewriting process" described below, the servo signal is rewritten on the magnetic tape MT, and a servo pattern (i.e., servo band SB) is formed. After the servo signal has been rewritten, the quality of the servo signal of the magnetic tape MT incorporated in the cartridge 10 is inspected again using the quality inspection device 240.

[0178] If the quality inspection device 240 finds that the quality of the servo signal is poor even after the "servo signal rewriting process" has been repeated a specified number of times (for example, three times), the cartridge 10 is discarded by the worker.

[0179] (Servo signal rewriting process) The servo signals are rewritten onto the magnetic tape MT of the cartridge 10 using the servo writer 210. Details of this process are as explained above in [5 Operation of the Servo Writer for Cartridge].

[0180] It is preferable that the quality inspection process be performed after a specified time has elapsed since the magnetic tape MT is incorporated into the cartridge 10. In other words, it is preferable that the servo signal be rewritten after a specified time has elapsed since the magnetic tape MT is incorporated into the cartridge 10. By performing the quality inspection, i.e., rewriting the servo signal, after the specified time has elapsed as described above, the width dimension of the magnetic tape MT is stabilized before the servo signal can be recorded on the magnetic tape MT. Therefore, the dimensional change in the spacing between the servo bands SB is reduced. The lower limit of the specified time is preferably one day or more, more preferably three days or more, and even more preferably seven days or more. A lower limit of one day or more can effectively stabilize the width dimension of the magnetic tape MT. The upper limit of the specified time is, for example, 30 days or less or 15 days or less, preferably seven days or less. A higher limit of the specified time is seven days or less, which can suppress a decrease in productivity.

[0181] After the assembly process and before the quality inspection process, the cartridge 10 may be annealed. By performing the annealing process in this manner, the width dimension of the magnetic tape MT is stabilized, and then servo signals can be recorded on the magnetic tape MT. From the viewpoint of stabilizing the width dimension of the magnetic tape MT, it is preferable to perform the annealing process for the above-mentioned specified time. The temperature for the annealing process is preferably 23°C or higher and 70°C or lower.

[0182] [8 Effects] As described above, the servo writer 210 according to an embodiment of the present disclosure includes a running unit that runs the magnetic tape MT by feeding the magnetic tape MT from the cartridge 10 and rewinding the fed magnetic tape MT; a demagnetizing magnet 214 that erases a first servo pattern formed on the running magnetic tape MT; a servo signal write head 215 that writes a servo signal to the running magnetic tape MT from which the first servo pattern has been erased, thereby forming a second servo pattern; and a control device 217 that controls the servo signal write head 215 to write servo signals during both the acceleration and deceleration periods of the magnetic tape MT, thereby forming a second servo pattern on the magnetic tape MT that does not meet the specifications. This allows the servo signal of a cartridge 10 whose servo signal has been confirmed to be of poor quality to be rewritten. This reduces the number of cartridges 10 that are discarded, thereby improving cartridge 10 productivity.

[0183] In terms of servo signal performance, when the drive reads the servo signal, it uses two servo signal reading elements (sensors) indicated by 51A and 51B (see FIG. 3), but the tape width, or in other words the spacing between the servo bands SB (servo band pitch), usually increases due to the effects of temperature, humidity, and winding pressure inside the cartridge 10. As a result, the position of the recording / reproducing elements may shift, making it difficult to read the data track Tk.

[0184] In contrast, as in the above-described embodiment, if the servo signals are recorded after the width dimension of the magnetic tape MT has stabilized after being wound into the cartridge 10 and stored for a specified time (e.g., after being stored for several days), the dimensional change in the spacing between the servo bands SB will be reduced. Therefore, the positional deviation of the recording / reproducing element will be reduced, the read accuracy of the data tracks Tk will be improved, and high track density will be achieved.

[0185] When magnetic tape MT is run, an acceleration region is required at the end of the tape that is being unwound, and a deceleration region is required at the end of the tape that is being unwound. If a recording current pattern with a fixed interval is applied to the acceleration and deceleration regions, a servo pattern that does not meet the standard will be created. On the other hand, to form a servo pattern that meets the standard, it is necessary to vary the time interval of the recording pattern by synchronizing the feed position of the magnetic tape MT with the recording current pattern, which is technically very difficult. In the servo writer 210 according to the embodiment described above, non-compliant servo patterns are recorded in the unused areas R1 and R7, thereby avoiding the above-mentioned difficulties. Furthermore, a pulse generating circuit conventionally used in pancake servo writers can be used as the pulse generating circuit 218.

[0186] [9 Variations] (Variation 1) In the above embodiment, a case has been described in which servo signals that do not meet the standard are written in the unused areas R1 and R7, but servo patterns may not be formed in the unused areas R1 and R7. In this case, servo patterns may not be formed in part of the unused area R1, or may not be formed in the entire unused area R1. Similarly, servo patterns may not be formed in part of the unused area R7, or may not be formed in the entire unused area R7.

[0187] The unused areas R1 and R7 are formed as follows when the servo writer 210 rewrites the servo signals: The control device 217 controls the servo signal write head 215 so as not to write servo signals during the acceleration and deceleration periods when the magnetic tape MT is running in the forward direction.

[0188] As described above, by not forming servo patterns in unused areas R1 and R7, it is no longer necessary to fabricate a pulse generating circuit capable of varying the recording pulse time in synchronization with the tape feed position, which is technically impossible, and it is possible to use the pulse generating circuit that has been conventionally used as pulse generating circuit 218.

[0189] (Variation 2) It is also possible that servo signals that do not meet the standard are written in one of unused area R1 and unused area R7, while no servo signals are written in the other area.

[0190] The unused areas R1 and R7 are formed when the servo writer rewrites the servo signals as follows: The control device 217 controls the servo signal write head 215 to write servo signals during one of the acceleration and deceleration periods when the magnetic tape MT is running in the forward direction, thereby forming a servo pattern that does not meet the standard on the magnetic tape MT, while controlling the servo signal write head 215 not to write servo signals during the other period, thereby not forming a servo pattern on the magnetic tape MT.

[0191] (Variation 3) In the above embodiment, the cartridge servo writer 210 is used to rewrite the servo signal. However, the cartridge servo writer 210 may also be used to write the initial servo signal. In this case, the initial writing of the servo signal is preferably performed a specified time after the magnetic tape MT is incorporated into the cartridge 10. After the incorporation process and before the quality inspection process, it is preferable to perform an annealing process on the cartridge 10. From the viewpoint of stabilizing the width dimension of the magnetic tape MT, it is preferable to perform the annealing process for the specified time.

[0192] Although the embodiments and modifications of the present disclosure have been specifically described above, the present disclosure is not limited to the above-described embodiments and modifications, and various modifications based on the technical concepts of the present disclosure are possible. For example, the configurations, methods, steps, shapes, materials, and numerical values ​​described in the above-described embodiments and modifications are merely examples, and different configurations, methods, steps, shapes, materials, and numerical values ​​may be used as necessary. The configurations, methods, steps, shapes, materials, and numerical values ​​of the above-described embodiments and modifications can be combined with each other as long as they do not deviate from the spirit of the present disclosure.

[0193] The chemical formulas of the compounds exemplified in the above-described embodiments and modifications are representative, and are not limited to the valences described as long as they are the general names of the same compounds. In the numerical ranges described in stages in the above-described embodiments and modifications, the upper or lower limit of a numerical range in one stage may be replaced with the upper or lower limit of a numerical range in another stage. Unless otherwise specified, the materials exemplified in the above-described embodiments and modifications can be used alone or in combination of two or more.

[0194] The present disclosure may also employ the following configuration. (1) a running unit that runs the magnetic recording medium by feeding the tape-shaped magnetic recording medium from the cartridge and winding up the magnetic recording medium that has been fed out; an erasing unit that erases a first servo pattern formed on the traveling magnetic recording medium; a head that writes a servo signal onto the traveling magnetic recording medium from which the first servo pattern has been erased, thereby forming a second servo pattern; a control unit that controls the head to write the servo signal during at least one of an accelerating period and a decelerating period of the magnetic recording medium, and forms the second servo pattern that does not meet the standard on the magnetic recording medium; A servo writer. (2) a running unit that runs the magnetic recording medium by feeding the tape-shaped magnetic recording medium from the cartridge and winding up the magnetic recording medium that has been fed out; an erasing unit that erases a first servo pattern formed on the traveling magnetic recording medium; a head that writes a servo signal onto the traveling magnetic recording medium from which the first servo pattern has been erased, thereby forming a second servo pattern; a control unit that controls the head so as not to write the servo signal during at least one of an accelerating period and a decelerating period of the magnetic recording medium; A servo writer. (3) The servo writer according to (1) or (2), wherein the head has five or more recording elements. (4) five or more recording elements each write the servo signal to the magnetic recording medium, thereby forming five or more servo bands; The servo writer according to (3), wherein the servo signal includes information for uniquely identifying each of the servo bands. (5) a wound tape-like magnetic recording medium; a case for accommodating the magnetic recording medium; Equipped with the magnetic recording medium has an unused area, A cartridge in which a servo pattern that does not meet the standard or no servo pattern is formed in the unused area. (6) The unused area is a first unused area provided at the end of the magnetic recording medium; a second unused area provided at the beginning of winding of the magnetic recording medium; The cartridge according to (5) above, (7) The cartridge according to (5) or (6), wherein the magnetic recording medium has five or more servo bands. (8) The cartridge described in (7) above, wherein the five or more servo bands include information for uniquely identifying each of the servo bands. (9) the magnetic recording medium comprises a magnetic layer; The cartridge according to any one of (5) to (8), wherein the squareness ratio of the magnetic layer in the perpendicular direction is 65% or more. (10) the magnetic layer contains magnetic powder, The cartridge according to (9), wherein the magnetic powder includes hexagonal ferrite, ε-iron oxide, or Co-containing spinel ferrite. (11) incorporating a tape-like magnetic recording medium into a cartridge; forming a servo pattern on the magnetic recording medium after a specified time has elapsed since the magnetic recording medium was incorporated into the cartridge; A method for writing a servo pattern including: (12) forming the servo pattern on the magnetic recording medium, A method for writing a servo pattern according to (11), comprising controlling a head to write a servo signal during at least one of an acceleration period and a deceleration period of the magnetic recording medium, and forming a servo pattern on the magnetic recording medium that does not meet the standard. (13) forming the servo pattern on the magnetic recording medium, feeding the magnetic recording medium from the cartridge and winding up the fed magnetic recording medium, thereby running the magnetic recording medium; erasing a first servo pattern formed on the running magnetic recording medium; writing a servo signal by a head onto the traveling magnetic recording medium from which the first servo pattern has been erased, thereby forming a second servo pattern; Including, forming the second servo pattern includes: A method for writing a servo pattern according to (11), comprising controlling the head to write the servo signal during at least one of an acceleration period and a deceleration period of the magnetic recording medium, and forming the second servo pattern that does not meet the standard on the magnetic recording medium. (14) incorporating a tape-like magnetic recording medium into a cartridge; forming a servo pattern on the magnetic recording medium after a specified time has elapsed since the magnetic recording medium was incorporated into the cartridge; A method for manufacturing a cartridge comprising: (15) forming the servo pattern on the magnetic recording medium, A method for manufacturing a cartridge as described in (14), which includes controlling the head to write a servo signal during at least one of an acceleration period and a deceleration period of the magnetic recording medium, and forming a servo pattern that does not meet the standard on the magnetic recording medium. (16) forming the servo pattern on the magnetic recording medium, feeding the magnetic recording medium from the cartridge and winding up the fed magnetic recording medium, thereby running the magnetic recording medium; erasing a first servo pattern formed on the running magnetic recording medium; writing a servo signal by a head onto the traveling magnetic recording medium from which the first servo pattern has been erased, thereby forming a second servo pattern; Including, forming the second servo pattern includes: A method for manufacturing a cartridge as described in (14), which includes controlling the head to write the servo signal during at least one of an acceleration period and a deceleration period of the magnetic recording medium, and forming the second servo pattern that does not meet the standard on the magnetic recording medium. [Explanation of symbols]

[0195] 10 cartridges 11 Cartridge Memory 12 cartridge case 41 Base 42 Base layer 43 Magnetic layer 44 Back layer 110 servo frames 111 Servo subframe 1 111A A Burst 111B B Burst 112 Servo subframe 2 112C C-Burst 112D D Burst 113 Servo Stripe 210, 220 Servo Writer 211 Cartridge storage section 211A Spindle 212 reels 213A, 213B, 213C, 213D Guide rollers 214 Degaussing Magnet 215 Servo signal writing head 216 Verify Head 217 Control Device 218 Pulse Generator Circuit 219A Spindle Drive Circuit 219B, 219C reel drive circuit 230 Winder 240 Quality Inspection Equipment MT magnetic tape SB Servo Band DB Data Binding

Claims

1. a running unit that runs the magnetic recording medium by feeding out the tape-like magnetic recording medium from the cartridge and winding up the magnetic recording medium that has been fed out; an erasing unit that erases a first servo pattern formed on the traveling magnetic recording medium; a head for writing a servo signal onto the traveling magnetic recording medium from which the first servo pattern has been erased, to form a second servo pattern; a control unit that controls the head to erase the first servo pattern and write the servo signal in at least one of a first unused area corresponding to an accelerating running period of the magnetic recording medium and a second unused area corresponding to a decelerating running period of the magnetic recording medium, and forms the second servo pattern that does not meet the standard in the at least one of the areas; A servo writer comprising:

2. a running unit that runs the magnetic recording medium by feeding out the tape-like magnetic recording medium from the cartridge and winding up the magnetic recording medium that has been fed out; an erasing unit that erases a first servo pattern formed on the traveling magnetic recording medium; a head for writing a servo signal onto the traveling magnetic recording medium from which the first servo pattern has been erased, to form a second servo pattern; a control unit that controls the erasing unit and the head so as not to write the servo signal after erasing the first servo pattern in at least one of a first unused area corresponding to an accelerating running period of the magnetic recording medium and a second unused area corresponding to a decelerating running period of the magnetic recording medium; A servo writer comprising:

3. 3. The servo writer according to claim 1, wherein the head has five or more recording elements.

4. five or more of the recording elements write the servo signals onto the magnetic recording medium, thereby forming five or more servo bands; 4. The servo writer of claim 3, wherein the servo signal includes information for uniquely identifying each of the servo bands.

5. 3. The servo writer according to claim 1, wherein the control unit controls the running unit, the erasing unit and the head so as to erase the first servo pattern and form the second servo pattern from the accelerating running period to the decelerating running period of the magnetic recording medium.

6. the second servo pattern includes a plurality of servo bursts; 2. The servo writer according to claim 1, wherein the second servo pattern not satisfying the standard is formed such that the tips of adjacent servo bursts overlap each other or the tips of adjacent servo bursts cross each other.

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