JPH04319510A - Production of composite head - Google Patents

Abstract

PURPOSE:To enhance mass productivity and to prevent the generation of off- tracking and chipping by integrally forming the respective core half body pairs and center spacers of a recording and reproducing head and an erasing head, then forming track regulating grooves. CONSTITUTION:Gap materials are formed by sputtering on a recording and reproducing core leg 2a, erasing core leg 2b and center core legs 3a, 3b consisting of Mn-Zn ferrite, etc. The leg 2a and the leg 3a as well as the legs 2b and 3b are joined and fixed. The recording and reproducing core 1a consisting of the legs 2a, 3a and the erasing core 1b consisting of the legs 2b, 3b are disposed apart a spacing. Glass rods 5a to 5e are melted by raising temp., by which the legs 2a, 2b, 3a, 3b are integrally welded. A center spacer 4 consisting of a nonmagnetic material is formed at this time. Two kinds of the track width regulating grooves 9a to 9c, 10a to 10c are formed in parallel with the sliding surface of the integrally welded core block 1. A magnetic film 6 is formed by sputtering on the leg 2a.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a composite head of advance erasing type suitable for recording and reproducing in data recording and reproducing devices such as FDDs (flexible disk drives).

0002

2. Description of the Related Art FIG. 3 is a perspective view of a conventional composite head shown, for example, in IEE SDNC materials.
E) Core legs 3a and 3b are center core legs, for which single crystal or polycrystalline Mn-Zn ferrite or Ni-Zn ferrite is used. 4 is a non-magnetic center spacer made of glass, ceramics, etc.; 5 is glass filled in the regulating groove 12 having the track width TW; 6 is a sendust alloy (Fe-Si-Al) or an amorphous alloy (e.g. Co- This is a magnetic film several microns thick made of (Zr-Nb). The head on which this magnetic film 6 is formed is called an MIG (metal-in-gap) head.
The head without the magnetic film 6 is called a ferrite head. After inserting coils into the recording/reproducing core legs 2a and the erasing core legs 2b, a shunt magnetic body is connected to the lower portions of the core legs 2a, 2b, thereby completing the head chip.

FIG. 4 is an enlarged view of the sliding surface of the above-mentioned composite head that comes into contact with the disk (medium). In the figure, 7
is a recording/reproducing (R/W) gap, 8 is an erasing (E) gap, and the gap length is 4MB (megabyte) specification, recording/reproducing gap 7 is 0.3 to 0.5 microns, and erasing gap 8 is 1 to 0.5 microns. It is 3 microns. Also, the gap interval is about 200 microns, and the recording/reproducing track width is 1
The erase track width is a little over 200 microns.

Next, the operation of the conventional advance erase type composite head described above will be explained. The erasing gap 8 is located in front of the recording/reproducing gap 7, and during recording, after erasing previously recorded data in the erasing gap 8,
New data is recorded in recording/reproducing gap 7. During reproduction, the recorded data is reproduced in the recording/reproducing gap 7. Current FDDs do not employ the tracking servo technology used in fixed disk devices, so track position shifts occur both during recording and reproduction. Therefore, a wide guard band is required to ensure data compatibility, and the track width of the erase gap 8 is set wider than the track width of the recording/reproducing gap 7.

[0005] Next, an outline of a conventional composite head processing method will be explained. The track width regulating groove 12 is processed for each core leg 2.
This is performed independently for each of a, 2b, 3a, and 3b. After that, the track positions of the recording/reproducing core leg 2a and the center core leg 3a and the erasing core leg 2b and the center core leg 3b are aligned, and then the track width regulating groove 12 is filled with glass 5. Next, the recording/reproducing core leg 2a and the center core leg 3 are integrated.
A non-magnetic material is installed between the erasing core consisting of the erasing core leg 2b and the center core leg 3b (actually between the center core legs 3a and 3b), which are integrated like the recording/reproducing core consisting of the recording/reproducing core consisting of a. All the core legs 2a, 2b, 3a, and 3b are integrated by bonding them with the center spacer 4 in between.

When glass is used for the center spacer 4, glass is poured into the center spacer portion at the same time as the step of filling the track width regulating groove 12 with the glass 5. As for the glass, in the case of ferrite heads, glass with a medium melting point whose working temperature is 700°C or higher is used, and M
In the case of the IG head, glass with a low melting point of 600° C. or less is used. The reason for using glass with a low melting point is to prevent the magnetic film 6 formed into a thin film by sputtering etc. from peeling off due to thermal stress, and to prevent the diffusion generated by the combination of the metal element of the magnetic film 6 and the oxygen of the ferrite. This is to suppress the formation of a reaction layer (which becomes a pseudo gap).

[0007]

[Problems to be Solved by the Invention] The conventional composite head is formed as described above, and each core leg 2a, 2b, 3a
, 3b, it is necessary to individually machine the track width regulating grooves 12, resulting in a problem of poor workability. Further, between the recording/reproducing core leg 2a and the center core leg 3a, the erasing core leg 2
This required track alignment at three locations: between the center core leg 3b and the recording/reproducing core, and between the recording/reproducing core and the erasing core, making it easy for track misalignment to occur, leading to a reduction in head performance margin. Furthermore, the track width regulating groove 12 is machined by mirror-polishing the gap surface and then mechanically grinding using a diamond wheel, but the chipping (chip at the track end) that occurs during this process results in a narrowing of the effective track width. This has become a major problem for recording/reproducing heads with narrow track widths.

The present invention was made to solve the above-mentioned problems, and aims to provide a method for manufacturing a composite head that is highly mass-producible and that can prevent track misalignment and chipping. do.

[0009]

[Means for Solving the Problems] A method for manufacturing a composite head according to the present invention includes a core half pair of an erase head (erasing core leg and center core leg), a non-magnetic center spacer, and a core half of a recording/reproducing head. After forming a gap material, the pair (recording/reproducing core leg and center core leg) are integrated to form a core block, and then track width regulating grooves for the erasing head and recording/reproducing head are formed on the sliding surface side of this core block. It is something.

[0010] Furthermore, in the method of manufacturing a composite head according to the present invention, after forming a preliminary groove for regulating the track width in the core half located at the rear with respect to the recording medium advancing direction of the pair of recording/reproducing head core halves, each head core is A gap material is formed on the working gap surface of the half pair, and then each head core half pair and center spacer are integrated to form a core block, and an erasing head is placed on the side of the core block that slides with the magnetic recording medium. The recording/reproducing head is machined with two types of grooves to regulate the track width.

The method for manufacturing a composite head according to the present invention further includes forming a magnetic film on the working gap surface of the rear core half of the pair of core halves of the recording/reproducing head before forming the gap material. It is.

0012

[Operation] In this invention, after the core half pair of the erasing head, the center spacer, and the core half pair of the recording/reproducing head are integrally formed, each track width regulating groove is formed, thereby eliminating the need for track alignment work. The frequency of groove machining is also less. or,
Since the gap surface does not appear on the grinding surface during groove machining, chipping does not occur.

Furthermore, since the gap material is formed after the magnetic film is formed, and then the core block is formed and the track width regulating groove is formed, the magnetic film is not formed in the groove.
The contact area between the glass filled in the groove and the magnetic film is small.

[0014]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a composite head according to this embodiment. For each core leg 2a, 2b, 3a, 3b, a single crystal or polycrystalline Mn-Zn ferrite or Ni-Zn ferrite, which is a metal oxide with high magnetic permeability, is used. Reference numeral 5 denotes a glass that is filled in the track width regulating groove and the center spacer, and lead-based glass is generally used. Glasses having different working temperatures are normally used for the ferrite head and the MIG head. 6 is a magnetic film made of sendust (Fe-Al-Si alloy), amorphous (
A high saturation magnetic flux density material, such as a Co-Nb-Zr alloy, is deposited by a thin film formation technique such as sputtering or ion plating. Recording/reproducing core leg 2a
A recording/reproducing coil and an erasing coil are respectively inserted into the and erasing core legs 2b, and a head core chip is completed by connecting a shunt magnetic body to the lower portions of the core legs 2a and 2b. Note that if the coil is directly wound, it is sufficient to have a closed magnetic circuit structure from the beginning.

FIG. 2 is an enlarged view of the sliding surface of the composite head according to this embodiment that comes into contact with the disk, where 7 is a recording/reproducing gap and 8 is an erasing gap.

Next, a method of manufacturing the magnetic head having the above structure will be explained with reference to FIGS. 5 to 12. FIG. 5 shows the ferrite piece 2 for the recording/reproducing core leg 2a and the erasing core leg 2b, and FIG. 6 shows the center core legs 3a, 3b. The ferrite piece 2 and center core legs 3a, 3b are finished to predetermined dimensions by grinding and lapping, and in particular, the surfaces that will become the gap surfaces are finished to a mirror surface without processing distortion. As shown in FIG. 7, a winding window groove 2c into which a coil is inserted is formed in the ferrite piece 2 by grinding using a diamond wheel, etc., and a recording/reproducing core leg 2a and an erasing core leg 2b are formed. A magnetic film 6 is formed on 2a by sputtering as shown in FIG. When forming the magnetic film 6, it is desirable that it be deposited only in the vicinity of the gap in order to prevent film peeling and generation of bubbles.

Next, a gap material is formed on each core leg 2a, 2b, 3a, 3b by sputtering, and the gap material is applied only to the core legs 2a, 2b or to the center core leg 3a.
, 3b may be formed in a single section. After forming the gap material, as shown in FIG. 9, the recording/reproducing core leg 2a and the center core leg 3a, and the erasing core leg 2b and the center core leg 3b are combined and fixed, and the recording/reproducing core 1a consisting of the core legs 2a and 3a is Erasing cores 1b consisting of core legs 2b and 3b are arranged at intervals, and glass rods 5a to 5e are arranged as shown in the figure, the temperature is raised to melt the glass rods 5a to 5e, and each core leg 2a, 2b, 3a, and 3b are welded together. At this time, the center spacer 4 is also formed.

Next, as shown in FIG. 10, two types of grooves 9a for regulating the track width are formed in the integrally welded core block 1.
~9c, 10a~10c are formed. That is, parallel to the sliding surface of the core block 1 with the magnetic recording medium, both cores 1a,
so that the line connecting the track ends of 1b becomes the end of the groove,
and core legs 2a, 3a, 2b, 3b of both cores 1a, 1b
The track width regulating grooves 9a of both cores 1a and 1b are arranged so that the tip of the groove is deeper than the lower end of the working gap where the cores join.
9c and 10a to 10c are formed by grinding using a diamond wheel, for example. Next, as shown in FIG. 11, the glass rod 5f is melted to form each groove 9a to 9c, 10.
Mold a to 10c with glass. Finally, after flattening the glass mold surface, as shown in Fig. 12, the areas A-B and C-D are first polished away using multi-wheel processing, and then the area E-F is removed using a wire or the like. By processing, a pre-elimination type composite head shown in FIG. 1 is obtained.

In the above embodiment, the recording/reproducing core 1a
Since the track width regulating grooves 9a to 9c and 10a to 10c are formed after integrally forming the center spacer 4 and the erasing core 1b, there is no need for track alignment work and the frequency of groove machining is reduced. Therefore, mass productivity is excellent and no track deviation occurs. Furthermore, since the gap surface does not appear on the grinding surface during groove machining, chipping does not occur.

Further, in the conventional composite head, since the magnetic film 6 is also formed in the track width regulating groove 12, when the track width regulating groove 12 is filled with glass 5, the magnetic film 6 and the glass 5 are separated.
However, in the above example, the magnetic film 6 was formed. Since groove processing will be carried out later, a magnetic film 6 is placed in the groove.
is not formed, and the contact area between the glass 5 filled in the groove and the magnetic film 6 becomes small, and the above-mentioned problem does not occur.

FIG. 13 is a perspective view of a composite head according to a second embodiment of the invention, and FIG. 14 is an enlarged view of the sliding surface that contacts the disk. The basic configuration is the same as that of the first embodiment, so the explanation thereof will be omitted and the manufacturing method will be explained.

First, as shown in FIG. 15, track width regulating preliminary grooves 13a to 13c are formed in the recording/reproducing core leg 2a in order to increase the ferrite surface and improve the characteristics. That is, track width regulating preliminary grooves 13a to 13c are formed obliquely from the surface facing the magnetic recording medium toward the working gap surface and deeper than the lower end of the working gap surface by grinding using a diamond wheel or the like. . Thereafter, as shown in FIG. 16, a magnetic film 6 is formed on the recording/reproducing core leg 2a by sputtering. When forming the magnetic film 6, it is desirable that it be deposited only in the vicinity of the gap in order to prevent film peeling and generation of bubbles.

Next, a gap material (not shown) is formed on each core leg 2a, 2b, 3a, 3b by sputtering. The gap material may be formed in a single layer only on the core legs 2a and 2b or only on the center core legs 3a and 3b. The gap material is formed of SiO2 or Ta2O5 by vapor deposition or sputtering. After forming the gap material, each core leg 2a, 2b, 3a, 3b is welded together as shown in FIG. At this time, the center spacer 4 is also formed, and the preliminary grooves 13a to 13c are also filled with glass.

Next, as shown in FIG. 17, two types of grooves 14 for regulating the track width are formed in the integrally welded core block 1.
a to 14c and 15a to 15c are formed. That is, first,
Both cores 1a, 1b pass through the side of the recording/reproducing core 1a without the preliminary grooves 13a to 13c and are parallel to the sliding surface with the magnetic recording medium.
along the line connecting the track ends of and both cores 1a, 1b
The track width regulating grooves 14a to 14c are deeper than the lower end of the operating gap where the core legs 2a, 3a, 2b, and 3b join together.
is formed by grinding with a diamond wheel,
Next, the track width regulating grooves 15a to 15c are passed through the side of the recording/reproducing head 1a where the preliminary grooves 13a to 13c are located.
form.

Next, the glass rod 5 is melted to form each groove 14a to
14c, 15a to 15c. Finally, after flattening the glass-molded sliding surface, as shown in Fig. 18, first the A-B and C-
The gap D is removed by polishing, and then processed using a wire saw or the like so that the gap E-F remains, to obtain a composite head of advance erasing type shown in FIG. 13.

In each of the above embodiments, the center spacer 4 is formed by molding glass, but the center spacer 4 may also be made of a ceramic plate made of calcium titanate or barium titanate, or a crystallized glass. In the case of crystallized glass, its surface is melted to form each core 1a.
, 1b. In the case of a ceramic plate, both cores 1
A thin film of glass is formed on the surface of a, 1b or the ceramic plate by sputtering or vapor deposition, and this glass is melted and fused. Alternatively, cathodic bonding may be performed by applying a potential between both cores 1a, 1b and a crystallized glass or ceramic plate. Both cores 1a and 1b may be integrated with each other and then integrated with the center spacer 4, or the three may be fused and integrated at the same time as in the embodiment.

Note that lead-based glass is usually used as molding or welding glass. In general, this glass has the property that the lower the lead content and the higher the working temperature, the higher the hardness and the higher the mechanical strength. Therefore, M.I.G.
For the head, erase core leg 2b and center core leg 3b
It is desirable to use high melting point glass with a working temperature of 800° C. or higher in the welding process to integrate the two. For other welding steps, glass with a low melting point of 500 to 600°C is used. Further, by attaching high melting point glass to the gap forming material of the erasing core 1b by vapor deposition or sputtering, its strength can be increased.

Further, in each of the above embodiments, the material of each core 1a, 1b is Mn-Zn or N, which is an oxide magnetic material.
i-Zn ferrite is used in the recording/reproducing core 1a, which is required to have excellent electromagnetic performance during recording and reproduction, in a pre-erase type composite head installed in an FDD with an operating frequency of 4 MHz or less. The erase core 1b uses Mn-Zn ferrite with excellent magnetic properties, and the erase core 1b, which only requires a DC erase function, uses Ni, which is highly workable.
By using -Zn ferrite, a composite head with a good balance between performance and mass productivity can be obtained.

Further, in each of the above embodiments, the case of a MIG head has been described, but it goes without saying that the present invention can also be applied to a ferrite head without the magnetic film 6.

[0030]

As described above, according to the present invention, the track width regulating groove is formed after each core half pair of the recording/reproducing head and the erasing head and the center spacer are integrally formed. does not occur, and mass productivity is improved.
Since the gap surface does not appear on the grinding surface during groove machining, chipping does not occur. Furthermore, since the track width regulating grooves are formed after forming the magnetic film, no magnetic film is formed in the grooves.
The contact area between the glass filled in the groove and the magnetic film is small, making it possible to prevent a decrease in strength due to a reaction between the two.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a composite head according to a first embodiment of the invention.

FIG. 2 is an enlarged view of the sliding surface of the composite head according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a conventional composite head.

FIG. 4 is an enlarged view of a sliding surface of a conventional composite head.

FIG. 5 is a perspective view of a ferrite piece according to the invention.

FIG. 6 is a perspective view of a center core leg according to the invention.

FIG. 7 is a perspective view of a manufacturing process of a recording/reproducing core leg and an erasing core leg according to the present invention.

FIG. 8 is a perspective view of the recording/reproducing core leg in the process of forming a magnetic film according to the present invention.

FIG. 9 is an explanatory diagram of the step of integrating each core leg according to the present invention.

FIG. 10 is a perspective view of the composite head according to the first embodiment of the present invention in a step of forming track width regulating grooves.

FIG. 11 is an explanatory diagram of a glass molding process for track width regulating grooves of a composite head according to the present invention.

FIG. 12 is a perspective view of the composite head according to the first embodiment of the present invention in an unnecessary portion removal process.

FIG. 13 is a perspective view of a composite head according to a second embodiment of the invention.

FIG. 14 is an enlarged view of a sliding surface of a composite head according to a second embodiment of the present invention.

FIG. 15 is a perspective view of a recording/reproducing core leg in a preliminary groove forming step according to a second embodiment of the present invention.

FIG. 16 is a perspective view of a recording/reproducing core leg in a magnetic film forming step according to a second embodiment of the present invention.

FIG. 17 is a perspective view of a composite head according to a second embodiment of the present invention in a step of forming track width regulating grooves.

FIG. 18 is a perspective view of a composite head according to a second embodiment of the present invention in an unnecessary portion removal process.

[Explanation of symbols]

1 Core block 1a Recording/reproducing core (recording/reproducing core half pair) 1b
Erasing core (erasing core half pair) 2a Recording/reproducing core leg 2b Erasing core legs 3a, 3b Center core leg 4 Center spacer 5 Glass 6 Magnetic film 7 Recording/reproducing gap 8 Erasing gap

Claims (3)

[Claims] Claim 1: An erase head comprising a pair of magnetic core halves made of a metal oxide with high magnetic permeability and having an operating gap between the core halves, a center spacer made of a non-magnetic material, and a metal oxide with high magnetic permeability. In the composite head in which recording/reproducing heads made of magnetic core half pairs and having operating gaps between the core halves are sequentially arranged, a gap material is applied to the operating gap surfaces of the erasing head core half pair and the recording/reproducing head core half pair. After forming, each pair of head core halves and a center spacer are integrated to form a core block, and a groove is machined on the side of the core block that slides against the magnetic recording medium to regulate the track width of the erasing head and the recording/reproducing head. A method for manufacturing a composite head, characterized in that: 2. An erase head comprising a pair of magnetic core halves made of a metal oxide with high magnetic permeability and having an operating gap between the core halves, a center spacer made of a non-magnetic material, and a metal oxide with high magnetic permeability. In the composite head in which recording/reproducing heads consisting of a pair of magnetic core halves and recording/reproducing heads having an operating gap between the halves are sequentially arranged, the core half located at the rear of the recording/reproducing head core half pair with respect to the direction in which the recording medium enters. After forming a preliminary groove to regulate the track width, a gap material is formed on the working gap surface of each pair of head core halves, and then each pair of head core halves and a center spacer are integrated to form a core block. A method for manufacturing a composite head, characterized in that a groove for regulating the track width of an erasing head and a recording/reproducing head is formed on the sliding surface side of the magnetic recording medium. 3. A high saturation magnetic flux density material such as sendust alloy or amorphous alloy is used before forming a gap material on the working gap surface of the rear core half of the pair of core halves of the recording/reproducing head with respect to the direction in which the recording medium enters. 3. The method of manufacturing a composite head according to claim 1, wherein the magnetic film is formed as a thin film.