JPS60136006A - Manufacture of ferrite head - Google Patents

Abstract

PURPOSE:To obtain a higher output than before and to improve characteristics of high-density magnetic recording and high-frequency magnetic recording by forming a protection film at a gap formation part and then etching the surface of a ferrite head core and improving magnetic characteristics. CONSTITUTION:Plural grooves are formed in a ferrite bar whose outside shape is polished, glass is molded 1 in the grooves, and the gap formation surface 2 is polished. Two ferrite bars formed as mentioned above are adhered mutually forming a gap 3 of spacers or a gap, and then cut into head cores. The surface of a head core is etched. The etching is carried out preferably slowly, so the surface is etched in hot phosphoric acid of 70 deg.C for 10min. Consequently, respective property constants become stable. Etching temperatures of the phosphoric acid from the room temperature to about 80 deg.C are adaptive sufficiently by varying the etching time. Further, the protection film 4 is formed of resin for protecting the formation part of the gap during the etching.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a ferrite head for audio or VTR.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a conventional head manufacturing method will be described with reference to the drawings.

A ferrite bar whose outer shape has been ground as shown in FIG. 1 (-) is prepared, and a plurality of grooves are formed in the ferrite bar as shown in (2). Next, as shown in (C), a glass mold 1 is placed in the groove, and the gap forming surface 2 is polished.

Using two ferrite bars molded in this way, (d
) The adhesive is bonded so that a gap 3 is formed by a spacer or void as shown in FIG. Silica-based glass is used as the spacer.

By cutting the bonded ferrite material (-)
Get a radcore like. In the steps shown in Figures 1(a) to (e), strained layers caused by various machining processes remain in the ferrite material, which causes deterioration in the squareness of the hysteresis curve, decrease in magnetic permeability, It induces an increase in coercive force. For this reason, in the production of conventional ferrite heads, it has not been possible to obtain high-output heads that fully reflect the physical constants of ferrite, which has been a serious hindrance, especially when performing high-frequency recording and reproduction.

Purpose of the Invention The present invention has been made to solve the above-mentioned conventional problems, and by removing distortion on the head surface by notching, the hysteresis curve can be made highly angular, the magnetic permeability can be increased, and the magnetic permeability can be increased. The purpose is to obtain a low coercive force, to be able to sufficiently cope with high-density magnetic recording in particular, and to obtain high output in a high frequency region.

Structure of the Invention In order to achieve this object, the present invention includes the following steps: preparing two ferrite bars whose outer dimensions have been ground; and machining a plurality of grooves in at least one of the ferrite bars.
The invention is characterized by comprising at least the steps of bonding the two ferrite bars to form a gear, cutting the metal bar into head cores, and etching the surface of the hemlock core. A method for manufacturing a ferrite head is provided.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the steps shown in FIGS. Etching the surface of the cut head core as in e). Since it is preferable to perform etching gently, in this example, etching was performed at 70'C.
Etching was performed for 10 minutes in hot phosphoric acid. Second
The figure shows the relationship between etching time with hot phosphoric acid at 70° C., normalized squareness, and coercive force, and shows that each physical property constant tends to become constant after about 10 minutes. still,
The etching temperature of phosphoric acid can be sufficiently adjusted from room temperature to about 80'C by changing the etching time. Also, care must be taken during etching to avoid erosion and destruction of the gap portion. In this example, no erosion damage occurred due to etching of the gap portion, but forming the protective film 4 made of resin as shown in FIG. 3 to protect the gap formation portion requires various etching methods. Effective when used.

The head chip 5 that had been etched as described above was subjected to polishing of the recording medium sliding surface 6 and winding 7 as shown in FIG. 4, and the self-recording/reproducing output was measured. 8 indicates a gap. The results are shown in FIGS.

Figure 6 shows the case where a C0-added α-F C20s coated tape is run at a relative speed of 5.81B8c. The output is +1. The output of esdB and ei-fusion became +2dB. Figure 6 shows a case where a vapor-deposited high-density metal tape is used and is run at a relative speed of 3.8 m/8 ec, and the output at 1'M is +3 dB.

The output of the 5 eyes is +adB. This shows that the ferrite head according to this example shows remarkable improvement in characteristics, especially for high-frequency magnetic recording, and exhibits an excellent effect on high-density magnetic recording media. ing.

Note that the plurality of grooves provided in the ferrite bar of the present invention may be provided in at least one of the two ferrite bars, and a glass spacer may be inserted into the gap formed. , it goes without saying that it may be a complete void.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention includes the steps of: preparing two ferrite bars whose outer dimensions have been ground; preparing the ferrite bars; and machining a plurality of grooves in at least one of the ferrite bars. a step of bonding the two ferrite bars to form a gap; a step of cutting the ferrite bar into a head core; and a step of etching the surface of the head core. This provides a method for manufacturing heads, in which the surface of a ferrite head core is etched,
By improving the magnetic properties, it is possible to achieve much higher output than before. Furthermore, significant improvements in the characteristics of high-density magnetic recording and high-frequency magnetic recording have led to
There are significant social effects.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing a conventional method for manufacturing a ferrite head, FIG. 2 is a diagram showing the relationship between etching time, squaring of the hysteresis curve, and coercive force according to the present invention, and FIG. 3 is a diagram showing the etching process according to the present invention. Fig. 4 is a schematic diagram of a head made by the manufacturing method of the present invention, and Fig. 6 is a diagram showing a conventional head and this manufacturing method for a C8-added α-Fe203 coated tape. FIG. 6 is a diagram showing a comparison of outputs between a conventional head and a head manufactured using the present method for vapor-deposited metal tape. 1...Glass mold, 2...Gap forming surface, 3...Gap, 4...Gap forming part protective film, 6...Surface Etched head core, 6... Recording medium sliding surface, 7.
...Winding, 8...Gap. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (1)

[Scope of Claims] 0) A step of preparing two ferrite bars whose outer dimensions have been ground, a step of machining a plurality of grooves in at least one of the ferrite bars, and a step of connecting the two ferrite bars. A method for manufacturing a ferrite head, which comprises at least the steps of forming a gap, cutting the ferrite bar into head cores, and etching the surface of the herad core. (2) Etching the herad core 2. The method of manufacturing a ferrite head according to claim 1, wherein a protective film is formed at least on the gap forming portion.