JPS6244324B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to preventing charging of a magnetic head, and more particularly to preventing charging of a ferrite magnetic head.

Most of the magnetic recording media currently in use are based on an insulating film or sheet of a high electrical resistance material, such as a resin such as polyethylene, coated with iron oxide as a magnetic material. When driven or used in contact with a high electrical resistance material such as a ferrite magnetic head, frictional static electricity is generated and affects the magnetic head as noise. It is widely known that a conductive metal case is placed around the outer periphery of a ferrite magnetic head so that it comes into contact with the magnetic recording medium to prevent the generation of frictional static electricity, or to be used as part of a grounding circuit for discharging. . However, in cases where small size, light weight, and wear resistance are required, such as magnetic heads for floppy disks, there is no room to provide such a conductive metal case. Furthermore, a disk head requires a sliding body called a slider, which is a non-magnetic material that is integrated adjacent to the magnetic head core and is intended to increase the surface that contacts or faces the magnetic recording medium. Usually, when the magnetic head core is made of ferrite, a barium titanate-based sintered body (white ceramic) is used as a non-magnetic ceramic material whose coefficient of thermal expansion and hardness are almost the same as those of ferrite, taking into account adhesion and processing with ferrite. Since this barium titanate-based sintered body is a high electrical resistance material with a resistivity of about 10 ¹¹ to 10 ¹² Ωcm, it has a resistivity of 10 ⁴ to ^{10 10} Ωcm compared to the Ni-Zn ferrite material used for ordinary magnetic head cores. The problem of static electricity generation has become serious.

In order to solve the above problem, a method was proposed in which a thin layer of conductive metal such as copper was provided on one side of the barium titanate sintered body forming the slider, as shown in Japanese Patent Application Laid-open No. 7311/1983. However, when the end surface of the thin layer comes into contact with a magnetic recording medium, the thin layer is not as hard as ferrite or barium titanate-based sintered bodies, and has poor wear resistance during processing and use of the head surface. The problem was that the manufacturing costs for providing the thin layer were high and were not a satisfactory solution. FIG. 1 shows a side sectional view of an embodiment of a magnetic head for a disk in which a thin electrically conductive layer 4 is applied to a slider 3. FIG.

In view of the above problems, this application has an antistatic function,
The purpose of the present invention is to provide a ferrite magnetic head that has good workability and wear resistance and is inexpensive.

The magnetic head of the present application will be explained below with reference to the drawings.

FIGS. 2a and 2b show a bottom view and a side sectional view of an embodiment of the magnetic head of the present invention applied to a disk head.

In FIGS. 2a and 2b, 1 is a ferrite head core part for reading and writing, 1a is a gap of the ferrite head core part 1 for reading and writing, 2 is a ferrite head core part for erasing, and 2a is a ferrite head for erasing. A gap 3 in the core portion 2 is a slider.

The features of this application are ferrite headed core part 1,
The slider 3 connected integrally with the head core is made of a non-magnetic ceramic material that has approximately the same coefficient of thermal expansion and hardness as the ferrite and has a low resistivity of 10 ⁸ Ωcm or less. It is formed using a black barium titanate-based sintered body obtained by sintering or ferrite, which is non-magnetic at room temperature.

The above-mentioned non-magnetic ferrite uses a ferrite having a Curie temperature of room temperature to below zero degrees. The composition of such ferrite with a low Curie temperature is
It is manufactured using materials with a high Zn content at a firing temperature of approximately 1250℃. From the viewpoint of resistivity, barium titanate-based sintered bodies obtained by reduction sintering are slightly more desirable.

The black barium titanate-based sintered body and non-magnetic ferrite obtained in this way have a resistivity of
It is a semiconductor with a resistivity of less than 10 ⁸ Ωcm and often on the order of 10 ² to ^{10 6} Ωcm. Furthermore, if the composition, additives, and firing conditions are selected, it is not difficult to obtain a black barium titanate-based sintered body and nonmagnetic ferrite with a resistivity of 10 ² Ωcm or less.

The low-resistivity non-magnetic material used in the above slider is the material for forming the ferrite head core parts 1 and 2, which is a necessary condition when they are integrally connected and bonded. It is not difficult to achieve substantially the same coefficient of thermal expansion and hardness since they are made of the same ceramic or ferrite material.

The resistivity of the above-mentioned black barium titanate-based sintered body and non-magnetic ferrite is not as high as that of conductive metals, but the area of contact with the magnetic recording medium is relatively large, and Like the ferrite head core, the structure and material of the slider, including the contact surface, has excellent wear resistance and remains stable for a long period of time. Therefore, the generation of frictional static electricity is sufficiently suppressed, and even if it occurs, the discharge grounding circuit will not be damaged. function as part of

Although not shown in FIGS. 2a and 2b, since the slider 3 itself can be directly connected to the grounding circuit of the device body to which the magnetic head of the present invention is attached, it is possible to connect the slider 3 itself directly to the grounding circuit of the device main body in which the magnetic head of the present invention is attached. This is advantageous because there is no need to provide electrodes as in the case of

In the embodiment of the present application, the slider of a magnetic head for a disk has been described, but it is obvious that the present invention can be similarly applied to a guard portion, a dummy portion, etc. of a general magnetic head, as required.

As described above, according to the magnetic head of the present application, at least a portion of the non-magnetic member integrally formed with the ferrite head core portion is uniformly connected to the magnetic recording medium facing surface of the ferrite head core portion. The sliding body with a smooth surface is made of a low-resistivity black barium titanate sintered body or non-magnetic ferrite, so it has an antistatic function and can be easily bonded to the ferrite head core and polished. Good workability. Furthermore, black barium titanate-based sintered body and non-magnetic ferrite were selected from among non-magnetic ceramics with a resistivity of 10 ⁸ Ωcm or less, resulting in extremely good wear resistance. This is an extremely useful invention as it can be manufactured much more inexpensively than the conventional means of forming a thin layer of conductive metal on one side of a slider made of a white barium titanate-based sintered body.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an embodiment of a magnetic head for a disk equipped with conventional antistatic means, and FIGS. 2a and 2b are bottom views of an embodiment of the magnetic head of the present application.
FIG. 1... Ferrite head core part for reading and writing, 2... Ferrite head core part for erasing,
1a, 2a...Gap, 3...Slider, 4...
...a thin conductive layer.

Claims (1)

[Scope of Claims] 1. A contact type magnetic head having a ferrite head core portion and a non-magnetic member integrally formed in connection with the ferrite head core portion, at least a portion of which includes a sliding surface with a magnetic recording medium. A sliding body having a smooth surface that is uniformly connected to the sliding contact surface of the magnetic recording medium of the ferrite head core portion is arranged, and the sliding body is made of a black barium titanate-based sintered body with a resistivity of 10 ⁸ Ωcm or less or a non-woven material. A contact type magnetic head characterized by being formed of magnetic ferrite. 2. The contact type magnetic head according to claim 1, wherein the non-magnetic ferrite is Zn ferrite. 3. The contact type magnetic head according to claim 1 or 2, wherein the resistivity is 10 ² to 10 ⁶ Ωcm.