JP3386909B2 - Manufacturing method of magnetic recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium. More specifically, the present invention improves the surface characteristics of a non-magnetic substrate (conductive substrate) of a magnetic recording medium by improving the surface characteristics of the magnetic recording medium, resulting in magnetic recording excellent in floating characteristics, lubricity and wear resistance. A method for manufacturing a medium.

[0002]

2. Description of the Related Art In recent years, with the development of information processing technology for computers and the like, magnetic recording media such as magnetic disks have been used as external storage devices. Conventionally, as a magnetic recording medium, an aluminum alloy substrate is subjected to alumite treatment or Ni.
A non-magnetic substrate that has been subjected to a non-magnetic plating treatment such as P plating is coated with an underlayer of Cr or the like, then with a magnetic thin film layer of a Co-based alloy, and then with a carbonaceous protective film. It is used.

In the above magnetic recording medium (hereinafter referred to as a magnetic disk), the distance between the magnetic disk and the magnetic head, that is, the flying height of the head, has become smaller as the density of the magnetic recording medium has increased, and recently, it is about 0.15 μm or less. Has become. With such a small flying height, if there is a protrusion on the surface of the magnetic disk, there is a risk of causing head crash and damaging the disk surface. Moreover, even the presence of minute projections that do not cause head crash can cause various errors when reading and writing information.

On the other hand, the magnetic disk is being miniaturized in parallel with the increase in capacity and density, and the drive motor for rotating the spindle is becoming smaller and smaller. For this reason, the torque of the drive motor may be insufficient, and the phenomenon that the magnetic head does not fly while being fixed to the magnetic disk surface is likely to occur. In order to prevent the magnetic head from crashing or sticking as described above, conventionally, a surface processing treatment (hereinafter, referred to as texturing) of further forming fine grooves on the disk surface after polishing the magnetic disk surface has been performed. Has been done. Texture processing is particularly effective in reducing the contact resistance between the magnetic head and the magnetic disk surface.

[0005]

As described above, although the flying characteristics of the head in the magnetic disk have been improved by the texture processing, the performance required for the magnetic disk has not yet been sufficiently met. By the way, in order to meet the above-mentioned demand, Japanese Unexamined Patent Publication (Kokai) No. 4-95221 proposes a surface treatment technique in which the magnetic disk is washed, and then chemical etching is further performed after the texturing.

However, in the chemical etching treatment, it is generally difficult to accurately control the surface condition by selecting the etching conditions, and the surface after etching tends to be non-uniform.

As a result of intensive studies to further improve the flying characteristics of the head in a magnetic disk, the present inventors have found that after the substrate surface is textured, the substrate surface is electrolytically treated in an electrolytic solution ( 1 method), and found that the surface of the substrate is improved.
Proposed earlier in No. 5.

However, when a plurality of substrates are simultaneously electrolytically treated by the above-mentioned first method, the etching amount of the substrate generated by the electrolytic treatment differs depending on each substrate, and even the same substrate has an etching amount in the in-plane direction. It turned out to be a different problem. Therefore, the present inventors have further provided counter electrodes (cathode plates) on the opposite sides of the substrate in the electrolytic solution,
It was found that this problem could be solved by applying a DC voltage between the substrate and the counter electrode to carry out electrolytic treatment (second method), and proposed it in Japanese Patent Application No. 6-14335.

However, according to the second method, although the quality of the product can be improved, it is necessary to dispose as many counter electrodes in the electrolytic solution as the number of substrates to be processed at the same time. Therefore, if this method is carried out on an industrial scale, the cost for the electrodes is high, and since the electrodes and the substrates are alternately arranged, the treatment efficiency is not always good in the electrolytic treatment of a large number of substrates. There was a circumstance.

In view of the above, the present invention provides a magnetic recording medium which can be processed on an industrial scale and at low cost while obtaining a substrate surface of good quality for the treatment after the texturing of the substrate of the magnetic recording medium. It is intended to provide a manufacturing method.

[0011]

DISCLOSURE OF THE INVENTION The inventors of the present invention have earnestly studied a method of manufacturing a magnetic recording medium, which can be advantageously carried out on an industrial scale in electrolytically treating a substrate after texture processing. As a result of repeating, the present invention was conceived and completed.

A method of manufacturing a magnetic recording medium according to the present invention comprises a texture processing step of texture-processing a conductive substrate,
A method of manufacturing a magnetic recording medium, comprising a thin film forming step of forming at least a magnetic layer on the surface of the conductive substrate,
Between the texture processing step and the thin film forming step, there is an electrolytic treatment step of treating a conductive substrate in an electrolytic solution, and the electrolytic treatment step sequentially processes a plurality of conductive substrates in a direction orthogonal to the substrate surface. It is characterized in that they are arranged side by side in the electrolytic solution, and an alternating voltage is applied between the odd-numbered conductive substrate and the even-numbered conductive substrate which are sequentially counted.

Here, the magnetic recording medium manufactured by the method of the present invention is not particularly limited, and any magnetic recording medium can be used as long as it is a magnetic recording medium manufactured by processing a conductive substrate by texture processing. As a conductive substrate,
Even if the entire substrate is not conductive, it is sufficient if the entire surface thereof is conductive. In addition, the thin film forming step in the present invention,
Generally, this includes formation of a base film and a magnetic film.

The alternating voltage electrically contacts the odd-numbered conductive substrates and is electrically insulated from the even-numbered conductive substrates to support the odd-numbered and even-numbered conductive substrates. A first electrically conductive support member and an even numbered electrically conductive substrate are electrically contacted with each other, and an odd numbered electrically conductive substrate is electrically insulated to support the even numbered and odd numbered electrically conductive substrates; It is preferable that it is configured to be applied between the two conductive supporting members. In this case, the supporting member also serves as a member for applying an alternating voltage, so that the apparatus for carrying out the method of the present invention is simplified.

Further, each of the conductive supporting members extends in the direction in which the conductive substrates are arranged, and a plurality of conductive members arranged on the conductive supporting rods corresponding to the conductive substrates. A stop member, and the conductive locking member has an abutting portion that abuts an outer peripheral edge of the conductive substrate, and supports electrical contact or insulation between the corresponding conductive substrate and the conductive support member. It is preferable that the conductive support member is electrically connected to or insulated from the conductive support member. In this case, the structure of the conductive support member is further simplified. The contact portion is, for example, a groove formed corresponding to the shape and size of the outer peripheral portion of the substrate.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on its preferred embodiments.

A disk-shaped substrate made of an aluminum alloy is generally used as the conductive substrate of the magnetic recording medium in the present invention. Usually, the aluminum substrate is processed to a predetermined thickness and then the surface thereof is mirror-finished. Then, a non-magnetic metal such as a Ni-P alloy or a Ni-Cu-P alloy is deposited by electroless plating to form a surface layer having a thickness of about 5 to 20 μm. Then, a surface processing is performed on this surface layer to form a surface processed layer having a specific surface roughness. As this surface processing treatment, for example, the surface layer is first subjected to polishing processing and then to texture processing, and then the substrate surface is subjected to electrolytic treatment in an electrolytic solution according to the method of the present invention.

Here, the polishing process is carried out, for example, by sandwiching the substrate between polishing pads having free abrasive grains adhered to the surface and impregnated with the polishing pads, and replenishing a polishing liquid such as a surfactant aqueous solution. Usually, the surface of the substrate is polished to a mean surface roughness Ra by performing polishing processing of about 2 to 5 μm.
Is less than 50Å (Angstrom), preferably less than 30Å. As the free abrasive grains, typically, an alumina-based slurry, such as Polypla 700 and Polypla 103 (both are registered trademarks of Fujimi Incorporated), a diamond-based slurry, and a SiC-based slurry are used. As a polishing pad, typically, Surfin10
For example, urethane foam such as 0 and Surfin XXX-5 (both are registered trademarks of Fujimi Incorporated) is used.

Further, as the texture processing, for example,
Use a polishing tape that carries about 2500 to 6000 # alumina abrasive grains, press the polishing tape against the polished substrate surface with a processing roller, and measure the average surface roughness in the circumferential direction of the substrate. Ra is 20Å or more, preferably 30 to 300
Å, more preferably, it forms fine grooves or irregularities in the range of 50 to 15Å with high precision. By this texture processing, adsorption between the magnetic head and the magnetic recording medium can be prevented, and CSS characteristics are improved. In addition, the magnetic anisotropy of the magnetic recording medium is improved.

In the method of the present invention, when the textured substrate surface is electrolytically treated in the electrolytic solution, a plurality of conductive (non-magnetic) substrates are sequentially arranged in the direction orthogonal to the substrate surface and arranged in the electrolytic solution. Then, by sequentially applying an alternating voltage between the odd-numbered conductive substrates and the even-numbered conductive substrates, the conductive substrates are treated in the electrolytic solution. After that, an underlayer and a magnetic layer are formed by a thin film forming process.

One example of a particularly preferred embodiment of the present invention is shown in FIG.
~ It demonstrates with reference to FIG. FIG. 1 is an elevational view of the inside of the electrolytic cell as viewed in the direction of the substrate surface, schematically showing how the substrate is subjected to electrolytic treatment. In FIG. 1, reference numeral 1 denotes an odd-numbered substrate sequentially counted from the left end in the drawing, and reference numeral 2 denotes an even-numbered substrate. A large number of the substrates 1 and 2 are arranged in an electrolytic bath 5 filled with the electrolytic solution 3 in a direction orthogonal to the substrate surface. Reference numeral 4 is an AC power source, and one line 6 thereof is connected to each odd-numbered substrate 1 and the other line 7 is connected to each even-numbered substrate 2 via a supporting member (not shown).

From the AC power source 4, a predetermined frequency (for example, 2
An alternating voltage composed of a rectangular wave of 0 Hz is output. Therefore, the odd-numbered substrates 1 and the even-numbered substrates 2 facing the odd-numbered substrates 1 alternately function as an electrode plate of an anode or a cathode,
By the alternating current flowing between the opposing substrates 1, 2,
The electrolytic treatment of each of the substrates 1 and 2 becomes possible. By this electric field treatment, protrusions and burrs on the substrate surface are removed by etching, and the substrate surface is finished in a smooth surface state.

FIG. 2 is a front view of the substrate viewed in a direction orthogonal to the substrate surface, showing the supporting condition of the substrate in the electrolytic cell, and FIG. 3 is a view taken along the line AA 'in FIG. is there. FIG. 2 is drawn as a diagram common to the odd-numbered and even-numbered substrates 1 and 2, so that the disc-shaped substrates 1 and 2 are spaced apart from each other in the circumferential direction of the disc to receive them. The three support members 11, 12 and 13 thus arranged support the disk at three points on the outer peripheral edge thereof. The number of the supporting members is 2 or more, and an arbitrary number is selected, but 3 or more is preferable for convenience of handling such as insertion and removal of the substrate.

The first and second support members 11 and 12 are
Each of them is configured as a conductive support member, for example, a metal member. As shown in FIG. 3, a conductive support rod 14 extending in the arrangement direction of the substrates near the outer peripheral portion of the substrate, and the conductive support rods 14 are electrically connected to each other. The first locking member 15 is supported while being in contact with each other, and the second locking member 17 is supported by the conductive support rod 14 while being electrically insulated. Each of the locking members 15 and 17 is made of, for example, a metal material, is formed in a substantially abacus ball shape, has a hollow hole to be inserted into the conductive support rod 14, and has an outer peripheral surface formed as an annular groove 18. The bottom of the annular groove 18 is in contact with the outer peripheral surfaces of the substrates 1 and 2 to support the conductive substrates 1 and 2 in the vertical direction and the horizontal direction and to make electrical contact with them.

The first locking member 15 is electrically and mechanically connected to the conductive support rod 14 by a screw 19. The second locking member 17 is insulated from and supported by the conductive support rod 14 via an insulating material 16 such as Teflon. The third support member 13 shown in FIG. 2 is an insulating support member having the same conductive support rods and second locking members as the conductive support members 11 and 12, and each conductive substrate Only mechanically support 1,2.

The current from the AC power source 4 flows into the first locking member 15 which is in electrical contact with the support rod 14 via the support rod 14 of the first conductive support member 11, for example. Further, the electric charges are given to the substrate from the outer peripheral edge of the corresponding odd-numbered conductive substrate 1 via the surface of the annular groove 18 of the first locking member. Then, from the even-numbered substrates 2 facing each other via the electrolytic solution, the second conductive support member 1 is similarly formed.
Return to AC power via 2. When the voltage polarity is reversed, it similarly flows in the opposite direction. Thus, the odd-numbered substrates 1 and the even-numbered substrates 2 facing the odd-numbered substrates 1 form counter electrodes facing each other. This enables electrolytic treatment of each substrate.

In the above, it is conceivable that the second locking member 17 for insulation itself is made of an insulating material such as Teflon. However, in this case, bubbles are generated in the locking member 17 during the electrolytic treatment. Adhesion is caused and the surface of the substrate in the vicinity of the supporting member is masked by air bubbles, resulting in uneven etching, which is not preferable.

In the method of the present invention, as described above, preferably in an electrolytic solution of an acidic solution, an alternating voltage is applied so that the current flowing through the substrate has a specific waveform, and the surface of the textured substrate is treated. Perform electrolytic treatment. Here, as the electrolytic solution, for example, sulfuric acid, nitric acid, hydrochloric acid, chromic acid,
An aqueous solution having a concentration in the range of 0.5 to 40% by weight, preferably 1 to 30% by weight, which is a combination of one or more of phosphoric acid, oxalic acid, acetic acid and the like is used, and an aqueous phosphoric acid solution is particularly preferable. The conditions of the electrolytic treatment include a liquid temperature of 10 to 70 ° C. and an average current density of 50 mA / cm ² or less, preferably 0.1 to 50 mA / cm ² ,
More preferably 0.5 to 45 mA / cm ² , electrolysis time 1 to 400 seconds,
Preferably 2 to 200 seconds, the amount of electricity (product of average current density and electrolysis time) is 10 to 1000 mA · sec / cm ² , preferably 50 to 600 mA ·
The range of seconds / cm ² is chosen.

The electric current used for the electrolytic etching is an alternating current having positive and negative polarities, that is, alternating polarities of the anode and the cathode, such as a sinusoidal single-phase alternating current or a rectangular wave.
An alternating current such as a triangular wave or a trapezoidal wave may be used.

FIGS. 4A to 4D show examples of current waveforms used in the electrolytic etching process. A sine wave (a), a rectangular wave (b), a trapezoidal wave (c), and a triangular wave (d) are illustrated. The frequency of the alternating current is preferably 0.1 to 500.
It is carried out within the range of Hz, more preferably 0.1 to 300 Hz. When an alternating current having such a waveform is used, the amount of electricity at the anode (QA) and the amount of electricity at the cathode (QA) in each substrate are
The ratio (QA / QC) with C) is 0 to 2.0, preferably
The range of 0.8 to 1.5, more preferably 0.9 to 1.1 is selected.

When a large number of substrates are electrolytically etched by using the method of the present invention with a high-concentration electrolytic solution, for example, an electrolytic solution of a phosphoric acid aqueous solution of 15% by weight (wt)% or more, variations in etching amount among the substrates are caused. Is small, and the modulation of the outer peripheral surface of the substrate, which is an index of electromagnetic conversion characteristics, is significantly improved, and the performance of the magnetic disk is improved.

Further, in the present invention, the electrolytic treatment described above suppresses the generation of pits on the substrate surface after texture processing, and removes protrusions, burrs and the like on the substrate surface by etching, so that the substrate surface is smooth. With the surface state, in the obtained magnetic disk, the flying characteristics and CSS characteristics of the head are significantly improved, and the magnetic characteristics such as coercive force are also improved.

If necessary, after the electrolytic etching treatment, a finishing treatment may be carried out to re-texture before laminating the underlayer and the magnetic layer. This texturing is, for example, a method in which loose abrasive grains are adhered to the surface of a substrate such as a cellulose nonwoven fabric and impregnated, or a tape carrying a relatively fine abrasive grain such as alumina is pressed against the substrate surface. You can do it.

Chromium (Cr) is formed as a secondary underlayer on the surface of the substrate that has been subjected to the electrolytic treatment by sputtering. The film thickness of this Cr underlayer is usually in the range of 50 to 2000Å. As the metal magnetic thin film layer formed on the Cr underlayer of such a substrate, Co-Cr, Co-Ni, Co-Cr are available.
A magnetic thin film layer of a Co-based alloy represented by -X, Co-Ni-X, Co-W-X or the like is preferable. Where X is L
i, Si, Ca, Ti, V, Cr, Ni, As, Y, Zr, N
b, Mo, Ru, Rh, Ag, Sb, Hf, Ta, W, Re, O
Examples include one or more elements selected from the group consisting of s, Ir, Pt, Au, La, Ce, Pr, Nd, Pm, Sm, and Eu. Such a metal magnetic thin film layer made of a Co-based alloy is usually deposited and formed on the underlayer of the substrate by means such as sputtering. The thickness of the metal magnetic thin film layer is generally in the range of 100 to 1000Å.

A protective thin film layer, preferably a carbonaceous film, is formed on the metal magnetic thin film. The carbonaceous protective thin film layer is usually used in the presence of a rare gas such as argon (Ar) or helium (He) or in the presence of a small amount of hydrogen.
It is formed by sputtering using carbon as a target, and is deposited as an amorphous carbon film or a hydrogenated carbon film. The thickness of this protective thin film layer is
It is usually in the range of 50 to 500Å. Further, in order to further reduce the coefficient of friction, a lubricating film may be further formed on the protective thin film.

[0036]

According to the manufacturing method of the present invention, the desired electrolytic treatment is performed accurately and uniformly on each substrate, so that the quality of the product is good, and since each substrate itself acts as an electrode, It is not necessary to dispose electrodes for each, and by omitting the electrode plate, each substrate can be handled easily.

Generally, in direct current electrolysis, the substrate is always an anode, and the Ni-P elution reaction and the anodization reaction simultaneously occur on the substrate surface. On the other hand, when an alternating current is applied to the substrate for electrolytic treatment, the substrate becomes the anode and the cathode alternately according to the current waveform. Ni-P elution reaction and anodic oxidation reaction occur simultaneously on the substrate surface at the time of anode, and H
₂ Gas generation reaction occurs. That is, in the electrolysis treatment using the alternating current, hydrogen generated on the substrate surface at the time of cathode consumes oxygen generated on the substrate surface at the time of anode, and the substrate surface is less likely to be oxidized than in direct current electrolysis. In addition, since the viscous layer near the substrate surface (presumed to be a saturated solution of Ni phosphate) is agitated by bubbling with H ₂ gas generated at the cathode, the etching rate on the substrate surface is made uniform. It is expected that the effect of promoting the cleaning and further cleaning the substrate surface by bubbling can be expected.

[0038]

EXAMPLES Next, the present invention will be further described with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 A substrate for a 3.5-inch disk made of an aluminum alloy, which was Ni-P plated to a thickness of about 15 μm by an electroless plating method, was prepared. Polish the surface of the substrate,
A film surface having an average surface roughness (Ra) of about 20 to 30Å was formed, and then fine grooves were formed by texturing with a polishing tape. Further, the disk was subjected to a texturing process using loose abrasive grains, and finished so that the average surface roughness (Ra) was about 60Å. next,
Using the apparatus shown in FIGS. 1 to 3, 20 substrates were collectively subjected to electrolytic treatment. In a 15 wt% phosphoric acid aqueous solution, the alternating voltage applied between the odd-numbered substrate and the even-numbered substrate is controlled so that the applied current becomes the rectangular-wave alternating current shown in FIG. 4 (b). Electrolytic treatment was performed. As the conditions for electrolytic treatment, the temperature of the electrolyte solution is 20 ° C and the average current density is 10 mA / cm.
² , frequency 20Hz and electrolysis time 20 seconds were adopted. The etching amount of the obtained substrate is shown in FIG. The average etching amount of the 20 substrates was about 3.96 mg / sheet, the variation between the substrates was sufficiently small, and the standard deviation was good at 10.5%.

Comparative Example 1 A substrate for a 3.5-inch disk made of an aluminum alloy plated with Ni-P to a thickness of about 15 μm by an electroless plating method was prepared. The surface of the substrate is polished to form a film surface having an average surface roughness (Ra) of about 20 to 30Å,
Next, fine grooves were formed by texturing using a polishing tape, and finishing was performed so that the average surface roughness (Ra) was about 100Å. Next, these 10 disk substrates are collectively subjected to electrolytic treatment by the method shown in the example of Japanese Patent Application No. 6-14335, and the electrolytic cell having the same capacity as that of the above-mentioned example 1 and having the configuration shown in FIG. A substrate 8 and an electrode plate 9 were alternately arranged so as to be parallel plate opposing electrodes in 5, and a DC voltage was applied from a DC power source 10. For the electrode plate 9 forming the cathode, a stainless material having the same shape as the disk substrate 8 was used.
The conditions for the electrolytic treatment are as follows: in a 10 wt% phosphoric acid aqueous solution, the distance between the electrodes is 12 mm, the liquid temperature is 20 ° C., the current density is ² mA / cm ² , and the electrolysis time is 10
0 seconds is adopted. Hydrogen was generated from the electrode plate 9. The etching amount of the obtained substrate is shown in FIG. The average etching amount per 10 sheets was 7.13 mg / sheet, and the standard deviation between the substrates was good at 5.43%.

As can be seen from the comparison between Example 1 and Comparative Example 1 described above, the electrolytic treatment method according to the present invention reduces the cost of the electrodes by omitting the electrode plate, and handles the insertion and removal of the substrate. Even though it has the advantage of being simplified, the variation in etching amount is not so large as compared with Comparative Example 1, and it is possible to manufacture a disk of stable and good quality.

[0042]

As described above, according to the method of manufacturing the magnetic recording medium of the present invention, the cost required for the electrodes and the man-hours for handling the substrate are reduced, so that the manufacturing cost of the magnetic recording medium is reduced and the quality is improved. The magnetic recording medium having a good magnetic field and a small variation can be produced.

[Brief description of drawings]

FIG. 1 is a schematic elevational view of the inside of an electrolytic cell showing how a method for manufacturing a magnetic recording medium according to an embodiment of the present invention is carried out.

FIG. 2 is a schematic elevational view showing a state of supporting a substrate in an electrolytic bath, as viewed in a direction orthogonal to the substrate surface.

FIG. 3 is a view on arrow A-A ′ of FIG.

FIG. 4 is a current waveform diagram used in electrolytic etching.

FIG. 5 shows the etching amount on each substrate obtained by the method of the example.

FIG. 6 is a schematic elevational view of the inside of an electrolytic cell for carrying out the comparative example method.

FIG. 7 shows the etching amount on each substrate obtained by the comparative example method.

[Explanation of symbols]

1 odd-numbered board 2 Even-numbered board 3 Electrolyte 4 AC power supply 5 electrolyzer 6, 7 power line 8 substrates 9 electrode plate 10 DC power supply 11, 12 conductive support member 13 Third Support Member 14 Conductive support rod 15, 17 Locking member (Soroban ball member) 16 Insulation material 18 annular groove

─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-5-128506 (JP, A) JP-A-54-101729 (JP, A) JP-A-5-209300 (JP, A) JP-A-63- 311000 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 5/62-5/858 C25F 3/04 B23H 3/04

Claims (2)

(57) [Claims] 1. A method of manufacturing a magnetic recording medium, comprising: a texture processing step of performing texture processing on a conductive substrate; and a thin film forming step of forming at least a magnetic layer on a surface of the conductive substrate, the texture processing step comprising: Between the thin film forming step and the electrolytic treatment step of treating the conductive substrate in the electrolytic solution, the electrolytic treatment step is performed by arranging a plurality of conductive substrates in a direction orthogonal to the substrate surface in order in the electrolytic solution. placement was carried out by applying an alternating voltage between the odd-numbered conductive substrate and the even-numbered conductive substrate counted sequentially, and, the alternating voltage, electrical said odd conductive substrate To
And to electrically connect with the even conductive substrate.
Insulated to support the odd and even conductive substrates.
A first conductive support member to hold, and the even-numbered conductive member
The odd-numbered conductive groups are in electrical contact with the substrate and
The plate is electrically insulated from the even-numbered and odd-numbered
A mark is formed between the second conductive support member supporting the conductive substrate and the second conductive support member.
A method of manufacturing a magnetic recording medium characterized by being added . 2. Each of the conductive support members extends in the direction in which the conductive substrates are arranged, and a plurality of conductive members arranged on the conductive support rods corresponding to the conductive substrates. A locking member, each of the conductive locking members has a contact portion that contacts the outer peripheral edge of the conductive substrate, and the electrical contact between the corresponding conductive substrate and the conductive support member or Corresponding to insulation, electrically connected or insulated with the conductive support member,
The method of manufacturing a magnetic recording medium according to claim 1 .