JPS61229214A - Magnetic head - Google Patents

Abstract

PURPOSE:To make possible the easy and inexpensive formation of a magnetic head and to prevent effectively tape squeaking by forming isolating members of a nonmagnetic alloy consisting essentially of Fe, masking or removing partly the part of the fixing material for magnetic cores which slides with a magnetic tape and setting the length in the sliding part of the magnetic cores at about >=1mm. CONSTITUTION:The isolating members 3, 3' are used to isolate the magnetic cores 1-1-1-4 and shielding members 4, 4' and are formed to a thin sheet shape. These members are so fixed that the top end faces thereof face the aperture of the sliding surface S. The nonmagnetic alloy consisting essentially of Fe is used for the material of the isolating members 3, 3' and the length l in the sliding direction of the top end faces of the cores 1-1-1-4 which slide with the magnetic tape is made as large as about >=1mm. A mask block is provided to the aperture of the sliding surface S so that the fixing material for the cores 1-1-1-4 does not face said aperture or the part of the fixing material facing the aperture 7 of a case 5 is removed to form a recess so that the material does not contact with the magnetic tape 8.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a magnetic head, and more specifically, the present invention relates to a magnetic head, and more specifically, a plurality of magnetic cores whose periphery is filled with a fixing material and fixed are made to slide against a magnetic tape to record and reproduce information. The present invention relates to a magnetic head having an isolating member that isolates a magnetic shielding member provided between the cores and the core, and in which the fixing member and the isolating member also slide on the magnetic tape during recording and reproduction.

[Prior Art] Conventionally, in this type of magnetic head, when the head slides against the magnetic tape, uncured substances and other substances in the binder of the magnetic tape adhere to the magnetic tape sliding surface of the head, resulting in uneven tape running. It is known that a so-called tape squeal phenomenon occurs in which noise consisting of a fundamental wave of 2 to 4 KHz and its harmonics is included in the reproduced output signal at the same time as the sliding noise is generated.

In this type of head, there are two places where debris from the magnetic tape tends to adhere: the above-mentioned fixing material part on the sliding surface of the magnetic tape, and the above-mentioned isolation member, which is conventionally made of a material such as nickel silver. . Further, in the case of a head for a compact cassette, etc., tape squeal is more likely to occur as detached matter adheres to the area on the tape sliding surface where the pressure of the tape pressing pad of the cassette is high, that is, around the center area.

However, none of the conventional heads of this type has completely taken measures against all of the above-mentioned points, and therefore tape squeal cannot be effectively prevented.

[Objective] The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a magnetic head that can effectively prevent so-called tape squeal by a structure that can be easily and inexpensively realized in the above-mentioned type of magnetic head. The purpose is to

[Structure of the Invention] In order to achieve such an object, in the present invention, in the magnetic head of the type first described in the technical field section, the isolation member between the magnetic core and the magnetic shielding member is made of Fe as a main component. At least a portion of the sliding portion of the fixing material of the magnetic core with the magnetic tape is masked or removed, and the length of the sliding portion of the magnetic core in the sliding direction is approximately one layer or more. A structure was adopted.

[Embodiments] Hereinafter, details of embodiments of the present invention will be described with reference to the attached drawings.

FIG. 1 is a front view of a magnetic tape sliding surface showing the structure of a magnetic head according to this embodiment.

The magnetic head shown in this figure has a compact cassette width of 3.
4 channels for recording and reproducing on 8mm magnetic tape,
It is configured as an auto-reverse type, and is designated by the code 1-1-.
It has a structure in which four magnetic cores indicated by 1-4 are fitted into a case 5, and a fixing material made of epoxy resin or the like (not shown here) is filled into the case 5 and fixed.

Each of the magnetic cores 1-1-1-4 is formed into a ring shape by abutting and joining a pair of core halves made of a laminate of high permeability magnetic thin plates such as permalloy, and has a ring shape on the abutting surface at the tip. A magnetic gap 2 is formed, and a winding (not shown) through which a recording/reproduction signal current is passed is wound at the rear, and the terminal end of this winding is similarly connected to a connection terminal (not shown). The magnetic cores 1-1 to 1-4 are fixed with the magnetic gap 2 facing a sliding surface S that slides on a magnetic tape (not shown), that is, an opening 7 formed on the top surface of the case 5. .

On the other hand, what is indicated by reference numeral 4.4' in FIG. 1 is the aforementioned shielding member that shields leakage magnetic flux between each magnetic core, and is made of a magnetic material such as permalloy into a thin plate shape as shown in the same figure.
It is arranged between each of the magnetic cores 1-1 to 1-4, and is fixed with its upper end facing the opening 7 of the sliding surface S.

Separating members 3, 3' are provided on both sides of each shielding member 4, 4' between the magnetic cores 1-1 to 1-4. The isolation members 3, 3' are for isolating each of the magnetic cores l-1 to 1-4 and each shielding member 4, 4' as described above, and are formed in a thin plate shape as shown in the figure, and have an upper end surface. is fixed facing the opening of the sliding surface S.

In this structure, the magnetic head of this embodiment takes the following measures to prevent tape squeal.

First, a non-magnetic alloy containing Fe as a main component is used as the material for the isolation member 3.3'. Preferred examples of this non-magnetic alloy include nickel-chromium steel, nickel-chromium-molybdenum steel, chromium steel, chromium-molybdenum steel,
There are manganese steel, manganese/chromium steel, aluminum/chromium/molybdenum steel, and stainless steel. Also, a combination of a plurality of these types may be used.

As a result of examining various materials for isolation members, it was confirmed that these non-magnetic alloys containing Fe as the main component are extremely difficult for magnetic tape particles to adhere to, compared to other materials. , by using this, the isolation member 3
, 3' can be prevented from adhering to fallen objects.

Further, in this embodiment, the length in the sliding direction of the tip surfaces of the magnetic cores 1-1 to 1-4 that slide against the magnetic tape is increased to about 1 layer or more. This and the above isolation members 3, 3
Due to the synergistic effect with the material structure of ', tape droplets are prevented from adhering to the vicinity of the central portion of the sliding surface S where the pressure of the tape suppressing pad of the cassette (not shown) is high.

Furthermore, in this embodiment, the magnetic core 1-1 is provided in the opening of the sliding surface S.
~Do not expose the fixing material of 1-4, and attach codes 8a and 6 to this part.
A mask block shown in b was provided to mask the fixing material in this part. The mask blocks 6a, 6b are formed of ceramic, ferrite, glassy carbon, metal spraying, or the like.

By doing so, it is possible to prevent the tape from adhering to the mask portion.

By taking the above-mentioned measures, according to the present embodiment, it is possible to prevent tape droplets from adhering to the sliding surface S, thereby effectively preventing tape squeal.

Further, deformation of the sliding surface S due to changes in humidity, temperature, etc. can be reduced by the mask blocks 6a, 6b, and the environmental resistance of the head can be improved.

Next, two tape squeal tests and their results will be explained in order to confirm the tape squeal prevention effect of this embodiment as described above.

In the first test, two types of isolation members were prepared: one made of stainless steel (JIS symbol 5US303) and one made of conventional nickel silver, and a mask block made of ferrite was prepared. The above-mentioned length J is 0.
Two types were prepared: 8W garden and 4.0 Peng layer.

Next, in the structure shown in Fig. 1, by combining the above two types of isolation members and magnetic cores and the structure of providing a mask block or exposing the fixing material to the opening, the structure shown in Table 1 below is obtained. Twenty heads of eight types of samples shown as Nos. 001 to 8 were created and prepared.

For each sample, the temperature was 55°C and the humidity was 50%.
γ-F e , 203 tape at a speed of 4.7 in an atmosphere of
The tape was slid at a speed of 5 cm/sec, the time from the start of sliding to the occurrence of tape squeal was measured, and the average and standard deviation for each sample were determined, and the results shown in Table 1 were obtained.

Table 1.

According to this Table 1, when the isolation member is 5US303, when a mask block is provided, and when the core length is 4
．． It can be seen that when the width is 0 mm, the tape squeal occurrence time is longer than when it is not, and a higher tape squeal prevention effect can be obtained.

In particular, the average tape squeal generation time of sample No. 008, which satisfies the above three conditions and corresponds to this example, is significantly longer than other samples, and its standard deviation is small. According to the results, it can be confirmed that an extremely excellent and consistent tape squeal prevention effect can be obtained.

Next, in a second test conducted to examine the effect of the core length J, a dummy core 8 made of ferrite was fitted into the case 5 as shown in Fig. 2, showing the sliding surface of the magnetic tape, and its tip surface was placed on the case 5. A dummy head was used, which faced the opening 7 of the sliding surface of the case 5 and was fixed by filling the inside of the case 5 with epoxy resin 9 as a fixing material. In this case, the length 1 of each dummy core as this dummy head is 0.8 mm and 0.8 mm.
5 layers, 1.0 am, 1.2+sm and 1.4 layers
We prepared 20 different types.

Then, we conducted a tape squeal test on each of these five types of dummy cores under the same conditions as mentioned above, and calculated the average and standard deviation of the tape squeal generation time for each type, and obtained the results shown in the ts2 table below. .

Table 2 According to this table, the core length 1 is 1. It can be confirmed that an excellent tape squeal prevention effect can be obtained if the thickness is equal to or higher than the OiI layer.

The length J of this core is very important.
If we use a non-magnetic alloy whose main component is It needs to be 1■■ or more.

Note that in the structure of the embodiment described above, the mask blocks 6a, 6
b is provided, but the mask block may not be provided and the part of the fixing material facing the opening 7 of the case 5 may be removed to form a recess so that it does not touch the magnetic tape 8. Even with such a structure, the above-mentioned method can be achieved. Similar effects can be expected.

Furthermore, the masking or removal of the portion of the fixing material facing the opening 7 may be performed not entirely but only in part.

Furthermore, I would like to add that the configuration of the present invention related to the isolation member, the masking or removal of the fixing material, and the core length J is not limited to the 4-channel, auto-reverse type for the compact cassette of the embodiment, but can be used in the first place. It is applicable to all of the types of magnetic heads mentioned in the technical field section.

[Effect] As is clear from the above description, according to the present invention, in the magnetic head of the type first described in the technical field section, the isolation member between the magnetic core and the magnetic shielding member is made of a non-containing material containing Fe as a main component. formed from a magnetic alloy, masking or removing at least a portion of the sliding portion of the fixing material of the magnetic core with the magnetic tape;
A simple and inexpensive structure in which the length of the sliding portion of the magnetic core in the sliding direction is approximately 1 μm or more provides an excellent effect of extremely effectively preventing tape squeal.

[Brief explanation of drawings]

FIG. 1 is a front view of a magnetic tape sliding surface showing the structure of a magnetic head according to an embodiment of the present invention, and FIG. FIG. 3 is a front view of a magnetic tape sliding surface showing the structure. 1-1 to 1-4...Magnetic core 2...Magnetic gap 3,3'...Isolation member 4.
4'...Magnetic shielding member 5...Case 6...Mask block 7...
Opening 8...Magnetic tape Figure 1 Figure 2

Claims (1)

[Claims] 1) Information is recorded and reproduced by sliding a plurality of magnetic cores whose periphery is filled with a fixing material and fixed on a magnetic tape, and a magnetic shielding member provided between the cores and the cores are made to slide on a magnetic tape. In the magnetic head, the separating member is made of a non-magnetic alloy containing Fe as a main component, and the fixing member and the separating member also slide on the magnetic tape during recording and reproduction. 1. A magnetic head, characterized in that at least a part of the sliding portion of the magnetic core with respect to the magnetic tape is masked or removed, and the length of the sliding portion of the magnetic core in the sliding direction is about 1 mm or more. 2) Nickel-chromium steel, nickel-chromium-molybdenum steel, chromium steel, chromium-molybdenum steel, manganese steel, manganese-
The magnetic head according to claim 1, characterized in that at least one of chrome steel, aluminum/chromium, molybdenum, and stainless steel is used.