JP2005158152A - Magnetic head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the generation of spacing loss due to tape traveling. <P>SOLUTION: In a magnetic head for which a winding wire groove is provided on at least one of a pair of magnetic core half bodies and the pair of magnetic cores are joined with a gap part, by using bismuth-based borosilicate glass as sealing glass, the generation of deposits on a head surface is reduced. Thus, since the sealing glass does not contain a lead oxide, the reaction of a magnetic tape material and the sealing glass does not occur, there is no level difference of the head surface due to reaction products and no deposition of the reaction products even when a tape is made to travel and there is the advantage that the generation of the spacing loss is little. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic head for a magnetic recording / reproducing apparatus in which output reduction due to spacing loss is small.

  Among magnetic recording / reproducing devices, in a device using a magnetic tape as a magnetic recording medium, when the tape is run, the product of the magnetic head and the material of the magnetic tape react with each other and the magnetic tape peeled off due to the friction of the sliding part. The magnetic powder adheres to the head surface, the adhesion between the magnetic head surface and the magnetic tape is impaired, so-called spacing loss increases, and the reproduction output of the magnetic head decreases. In particular, the above phenomenon is remarkable in a high temperature and low humidity environment.

As an improvement measure, there is a method in which the surface of the magnetic head is coated with a protective film to prevent adhesion of magnetic powder or the like and wear of the magnetic head (see, for example, Patent Document 1). However, this method requires an apparatus and man-hours for coating the protective film, which increases the manufacturing cost. Further, there is a problem that the protective film is peeled off by running the tape, and the effect of preventing the spacing loss is impaired.
JP-A-9-320041

  The problem to be solved is the generation of spacing loss due to foreign matter adhering to the head surface. Conventionally, a glass containing lead oxide has been used as a sealing glass for a magnetic head in order to seal at a low temperature. However, glass containing lead oxide is inferior in durability to acids and alkalis (chemical durability). For example, in a magnetic head using glass containing lead oxide, when the magnetic head is mounted on a video tape recorder and the video tape slides, stearin, which is a component of a lubricant applied to the surface of the video tape, is used. Acid and lead oxide, which is a component of the sealing glass of the magnetic head, react to produce lead stearate. As a result of this reaction, lead is lost from the glass surface, the composition of the glass changes, and the wear properties of the glass change, resulting in a step in the part that did not react and a spacing loss. There is. In addition, spacing loss may occur due to adhesion of reaction products.

  The main feature of the present invention is that bismuth-based borosilicate glass that does not react with the magnetic tape material is used as the sealing glass of the magnetic head.

  In the magnetic head of the present invention, since the sealing glass does not contain lead oxide, the reaction between the magnetic tape material and the sealing glass does not occur. There is an advantage that there is no adhesion of reaction products and there is little generation of spacing loss.

  By using bismuth-based borosilicate glass as the sealing glass, we realized a head that is less susceptible to spacing loss.

(Embodiment 1)
FIG. 1 shows an example of a magnetic head according to claims 1 to 4 of the present invention, wherein a winding groove is provided in at least one of a pair of magnetic core halves, and the pair of magnetic cores is a gap. In the magnetic head bonded with a portion, a pair of magnetic core halves 1 and 2 are bonded by a sealing glass 4.

(Embodiment 2)
FIG. 3 shows an example of the head according to claims 5 to 8 according to the present invention, wherein a winding groove is provided in at least one of the pair of magnetic core halves, and the pair of magnetic core halves In the magnetic head in which the metal magnetic film is formed on the bonding surface of at least one of the magnetic core halves, the pair of magnetic core halves 1 and 2 are bonded to each other with a sealing glass 4.

  In the magnetic head of the present embodiment as described above, since the sealing glass does not contain lead oxide, the reaction between the magnetic tape material and the sealing glass does not occur, and the head is caused by the reaction product even when the tape runs. It can be supplied as a magnetic head in which there is no generation of a step on the surface, no adhesion of reaction products, and little generation of spacing loss. In addition, the material conventionally used can be used for the magnetic material in the above magnetic head.

  Hereinafter, embodiments of the magnetic head of the present invention will be described, but the present invention is not limited thereto.

  FIG. 1 is a schematic view showing a typical structure of a head according to a fourth aspect of the present invention. The ferrite core halves 1 and 2 are joined together by a sealing glass 4. Here, the sealing glass 4 has an oxide conversion of 9.0% by weight of SiO2, 9.6% by weight of B2O3, 18.3% by weight of ZnO, 58.2% by weight of Bi2O3, and 4.0% of Al2O3. A glass having a composition containing 1% by weight, 0.8% by weight of Na2O and 0.1% by weight of La2O3 was used. The composition ratio of the bismuth borosilicate glass used for the sealing glass 4 is based on the description in Japanese Patent Application No. 2002-308206.

First, the sealing glass is molded at 660 ° C. on a ferrite strip formed into a predetermined shape, the surface is polished, and Pyrex (R) and SiO 2 are sputtered as a gap material to produce ferrite core halves 1 and 2. did. Next, the ferrite core halves 1 and 2 are butted against each other and held by a jig, and then sealed at 650 ° C. Further, the outer shape is processed into predetermined dimensions and shapes, and then cut into head chips.

  Next, a magnetic head was manufactured using the manufactured head chip 5. After the head chip 5 is mounted on the head base 6 and the lead wire 7 is wound around the head chip 5, both ends of the lead wire 7 are soldered to the wiring board on the head base 6 to complete the head shown in FIG. did.

(Embodiment 3)
FIG. 3 is a schematic view showing a typical structure of a head according to claim 8 of the present invention. The ferrite core halves 8 and 9 are joined together with a sealing glass 11 and a sealing glass 12. Here, the sealing glass 11 is composed of 4.8% by weight of SiO2, 7.6% by weight of B2O3, 12.8% by weight of ZnO, 73.3% by weight of Bi2O3 and 1.0% of Al2O3 in terms of oxide. Glass having a composition containing 0.5% by weight of La2O3 by weight, and sealing glass 12 is 3.2% by weight of SiO2, 6.6% by weight of B2O3, and 12.4% by weight of ZnO in terms of oxides. %, Bi2O3 75.6 wt%, Al2O3 1.0 wt%, Na2O 0.6 wt% and La2O3 0.6 wt%. The composition ratio of the bismuth borosilicate glass used for the sealing glass 4 is based on the description in Japanese Patent Application No. 2002-308206.

  First, ferrite core halves 8 and 9 were fabricated by sputtering a protective film, a magnetic film, a protective film, and a gap material in this order on a ferrite strip formed into a predetermined shape. Next, the ferrite core halves 8 and 9 are brought into contact with each other and held by a jig. The front gap sealing glass 11 and the sealing glass 12 processed into a predetermined shape are respectively arranged at predetermined positions and sealed at 515 ° C. Further, the outer shape is processed into predetermined dimensions and shapes, and then cut into head chips.

Next, a magnetic head was produced using the produced head chip 13 in the same manner as in the first embodiment.
As a comparative example of the second embodiment, instead of the sealing glass 11 of the second embodiment, 9.9% by weight of SiO2, 12.3% by weight of B2O3, and 4.5% by weight of ZnO in terms of oxides. A lead glass having a composition containing 70.4% by weight of PbO, 1.6% by weight of Al2O3 and 1.3% by weight of Na2O is used, and instead of the sealing glass 12, SiO2 is converted to 5. A magnetic head was fabricated in the same manner as in the above embodiment, using lead glass having a composition containing 1% by weight, B2O3 14.2% by weight, PbO 77.0% by weight, and Al2O3 3.7% by weight. .

  The obtained heads of Embodiment 2 and Comparative Example were mounted on a video deck, and a running test was performed in a high-temperature and low-humidity environment (40 ° C., relative humidity 5%). A coating type magnetic tape was used as the magnetic tape. The output at 20.9 MHz of each head was measured every minute while the tape was running, and the difference from the output at the start of the test was examined. The test results are shown in Table 1.

  As shown in Table 1, the magnetic head according to the third embodiment of the present invention has a decrease in output 54 minutes after the start of the test, that is, a scan, compared to the head of the comparative example using lead glass as the sealing glass. Less pacing loss.

  In the above description, the example of the magnetic head according to claim 8 of the present invention has been described. However, the same effect can be obtained with other magnetic heads.

  In the magnetic head according to the present invention, since the sealing glass does not contain lead oxide, there is no reaction between the magnetic tape material and the sealing glass, and there is no generation of a step on the head surface due to the reaction product even when the tape runs. Therefore, it is advantageous as a magnetic head for a magnetic recording / reproducing apparatus having an advantage that the generation of spacing loss is small and an output decrease due to the spacing loss is small.

The figure which showed the typical structure of the head chip | tip of the head of Embodiment 1 of this invention. The figure which showed the typical structure of the head of Embodiment 2 of this invention. The figure which showed the typical structure of the head chip of the head of Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core half body 2 Core half body 3 Magnetic gap 4 Sealing glass 5 Magnetic head chip 6 Head base 7 Conductor 8 Core half body 9 Core half body 10 Magnetic gap 11 Sealing glass 12 Sealing glass

Claims (8)

In a magnetic head in which a winding groove is provided in at least one of a pair of magnetic core halves and the pair of magnetic cores are joined with a gap portion, the composition includes SiO2, B2O3, ZnO, Bi2O3 as sealing glass A magnetic head using a glass having In a magnetic head in which a winding groove is provided in at least one of a pair of magnetic core halves and the pair of magnetic cores are joined with a gap portion, the composition includes SiO2, B2O3, ZnO, Bi2O3 as sealing glass And 0 to 10% by weight of at least one selected from Li2O, Na2O and K2O in terms of oxide, and 0 to 30% by weight of at least one selected from MgO, CaO, SrO and BaO. A magnetic head characterized by being used. In a magnetic head in which a winding groove is provided in at least one of a pair of magnetic core halves and the pair of magnetic cores are joined with a gap portion, SiO2, B2O3, ZnO, Bi2O3, Al2O3 are used as sealing glass. And having a composition containing 0 to 10% by weight of at least one selected from Li2O, Na2O and K2O and 0 to 30% by weight of at least one selected from MgO, CaO, SrO and BaO in terms of oxide. A magnetic head using glass. In a magnetic head in which a winding groove is provided in at least one of a pair of magnetic core halves and the pair of magnetic cores are joined with a gap portion, SiO2, B2O3, ZnO, Bi2O3, Al2O3 are used as sealing glass. 0 to 10% by weight of at least one selected from Li2O, Na2O and K2O in terms of oxide, 0 to 30% by weight of at least one selected from MgO, CaO, SrO and BaO, Sc2O3, Y2O3 A composition containing 0.1 to 10% by weight of a glass containing at least one selected from La2O3, CeO2, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3 and Lu2O3 Magnetic head characterized by The pair of magnetic core halves, wherein a winding groove is provided in at least one of the pair of magnetic core halves, and a metal magnetic film is formed on a bonding surface of at least one of the pair of magnetic core halves. In a metal-in-gap type head in which gaps are formed by bonding each other with sealing glass, a magnetic head using glass having a composition containing SiO2, B2O3, ZnO, Bi2O3 as the sealing glass . The pair of magnetic core halves, wherein a winding groove is provided in at least one of the pair of magnetic core halves, and a metal magnetic film is formed on a bonding surface of at least one of the pair of magnetic core halves. In the metal-in-gap type head in which gaps are formed by bonding each other with sealing glass, the sealing glass has a composition containing SiO2, B2O3, ZnO, Bi2O3, and Li2O, Na2O in terms of oxide And a glass having a composition containing 0 to 10% by weight of at least one selected from K2O and 0 to 30% by weight of at least one selected from MgO, CaO, SrO and BaO. The pair of magnetic core halves, wherein a winding groove is provided in at least one of the pair of magnetic core halves, and a metal magnetic film is formed on a bonding surface of at least one of the pair of magnetic core halves. In a metal-in-gap type head in which gaps are formed by bonding each other with a sealing glass, the sealing glass has a composition containing SiO2, B2O3, ZnO, Bi2O3, Al2O3, and Li2O in terms of oxide A magnetic head using a glass having a composition containing 0 to 10% by weight of at least one selected from Na2O and K2O and 0 to 30% by weight of at least one selected from MgO, CaO, SrO and BaO. The pair of magnetic core halves, wherein a winding groove is provided in at least one of the pair of magnetic core halves, and a metal magnetic film is formed on a bonding surface of at least one of the pair of magnetic core halves. In a metal-in-gap type head in which gaps are formed by bonding each other with sealing glass, the sealing glass has a composition containing SiO2, B2O3, ZnO, Bi2O3, Al2O3, and Li2O in terms of oxide , At least one selected from Na2O and K2O is 0 to 10% by weight, at least one selected from MgO, CaO, SrO and BaO is 0 to 30% by weight, Sc2O3, Y2O3, La2O3, CeO2, Pr2O3, Nd2O3, Sm2O3, Eu2O3 , Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Magnetic head is characterized in that a glass having a composition including at least one of 0.1 to 10 wt% selected from b2O3 and Lu2O3.

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