JPH0573837A - Multichannel magnetic sensor - Google Patents

Abstract

PURPOSE:To provide a multichannel magnetic sensor in which leaked magnetic flux is prevented. CONSTITUTION:This magnetic sensor is provided with a pair 2A, 2B of front and rear cores 2 on the left and right in plural pieces. Inter-channel sealed plates 5 which are arranged between the cores 2, and spacers 6 installed between cores on both sides of this inter-channel sealed plates 5, are arranged in a pair of front and rear parts in the same manner as the cores 2, and simultaneously a soft magnetic material 7 is arranged between the front and rear abutting parts of the inter-channel magnetic sealed plates 5. The leaked magnetic flux is prevented, unnecessary recording between the tracks of a recording medium is eliminated and erros at the time of reproduction are also eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-channel magnetic sensor, and more particularly, to a magnetic sensor used in a multi-channel magnetic recording / reproducing system such as an automatic ticket gate or a prepaid card system which requires simultaneous recording / reproducing in two or more channels. It is about sensors.

[0002]

2. Description of the Related Art Conventionally, a magnetic sensor used in a multi-channel magnetic recording / reproducing system is, as shown in FIG. 3, a front and rear portion of each of a plurality of core insertion portions 12 formed in the left-right direction at a mating portion of a pair of front and rear holders 11. While providing a pair of cores 13, the slits 14 formed alternately with the core insertion portions 12 in the mating portion of the holder 11 also have soft magnetic properties for preventing magnetic interference between the cores 13 (channels). Material magnetic shield plate (hereinafter referred to as inter-channel shield plate) 15
Is provided through the gap portion 16 of the core.

However, in the structure of the holder 11 of the magnetic sensor described above, in the case of a magnetic sensor in which the channel width of the core 13 is large and the channel pitch is small, the width of the portion 17 where the slit 14 for inserting the inter-channel shield plate 15 is formed. Becomes narrower, it becomes difficult to form the slit 14 in the holder 11 by machining or the like.

Therefore, instead of forming the slit 14, for example, as shown in FIG.
12 are formed in series, and core 13 and inter-channel shield plate 15
The method of using the inter-core spacer 18 between the two is adopted.

[0005]

By the way, in the case of the method of connecting the left and right core insertion portions 12 of the holder 11 and using the inter-core spacer 18 as described above, since the core 13 is positioned in the left and right direction, It is necessary to set the inter-channel shield plate 15 and the inter-core spacer 18 before the butting surface wrapping. For this reason, the inter-channel shield plate 15 must be divided into two parts, the front and rear parts. When using the inter-channel shield plates 15A and 15B that are divided into two parts,
When the front and rear holders 11A and 11B are butt-loaded into the shield case (not shown) after wrapping the abutting faces of the core 13, if the gap member 19 is inserted between the abutting faces of the core 13, the inter-channel shield plates 15A and 15B are inserted. When a multi-channel magnetic sensor is used, a gap is created between the abutting surfaces of the recording medium, and a magnetic flux leaks from there, resulting in unnecessary recording between tracks on the recording medium, causing an error during reproduction. Occur.

The present invention has been made in view of the above problems, and an object thereof is to provide a multi-channel magnetic sensor in which leakage magnetic flux is prevented even if a two-divided inter-channel shield plate is used. That is.

[0007]

In order to achieve the above object, a multi-channel magnetic sensor according to the present invention is a multi-channel magnetic sensor having a plurality of front and rear paired cores, which are arranged between the cores. The inter-channel shield plate to be installed and the inter-core spacers on both sides of this inter-channel shield plate are arranged in a front-rear pair in the same manner as the core, and
A soft magnetic material is disposed between the front and rear butting portions of the inter-channel magnetic shield plate.

[0008]

The present inventors have found that an error occurs during reproduction when recording is performed on a recording medium using a multi-channel magnetic sensor using a two-divided inter-channel shield plate. Therefore, when conducting research, we found that the cause of the error was the gap between the channel shield plates, which was about the same amount as the gap material with a thickness of several tens of μm provided between the abutting faces of the front and rear cores. The present invention has been completed by finding out what can be prevented by inserting a soft magnetic material having substantially the same thickness as the gap material into this void.

When the soft magnetic material is inserted into the space between the shield plates between the channels as described above, interference between the tracks is blocked and errors such as unnecessary writing on the recording medium are completely prevented.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of a holder of a multi-channel magnetic sensor according to the present invention seen from a core surface, and four sets of cores 2 are incorporated in the holder 1.

The holder 1 is formed by a pair of front and rear holders 1A and 1B, and a recess 3 having a size for incorporating four sets of cores 2 is formed on the abutting surface side.

The core 2 is formed by a pair of front and rear cores 2A and 2B, and four sets are incorporated in this example.

Reference numeral 4 denotes an inter-core gap material, which is formed to have a thickness of 50 μm and is inserted between the abutting surfaces of the cores 1A and 1B.

Reference numeral 5 is an inter-channel shield plate, 6 is an inter-core spacer, and each of the inter-channel shield plate 5 and the inter-core spacer 6 is divided into two parts, that is, a pair of front and rear inter-core spacers 6A and 6B, and an inter-channel shield plate. The inter-channel shield plates 5A, (5B) are formed between the cores 2A, (2B) by disposing inter-core spacers 6A, (6B) on both sides thereof.

Reference numeral 7 is a gap material between shield plates, which has the same thickness as the gap material 4 between cores.
It has a thickness of 50 μm and is inserted between the abutting surfaces of the inter-channel shield plates 5A and 5B.

The two sets of holders constructed as above are
In the same way as before, the left and right columns were placed in a line in a shield case (not shown), and after resin molding and drying and curing, the channel surface (core surface) was polished to complete an 8-channel magnetic sensor for automatic ticket gates. The specifications at this time are as follows. Channel width: 3mm Channel pitch: 3.8mm Material of gap material between cores: Cu-Be alloy Thickness of gap material between cores: 50μm Material of shield plate between channels: PC permalloy Material of gap material between shield plates: PC permalloy shield plate Thickness of gap material: 50μm

For comparison, an 8-channel magnetic sensor having the same structure and specifications as the present invention, in which a gap material between shield plates is not inserted, was manufactured.

Using these, after recording under the following conditions, magnetic fluid was applied onto the recording medium, and the recording stripes were developed and observed.
A part of the recording stripes after development at this time is enlarged and shown in FIG. Recording medium: Holding power 2750 Oe Recording density: 210 bpi Transport speed: 2 m / s

As is apparent from FIG. 2, in the sensor of the present invention, there is no abnormality such as dots between the cores,
In the sensor of the comparative example, a point is recognized between the core,
It can be seen that there was a leakage magnetic flux.

[0020]

As described above, the multi-channel magnetic sensor according to the present invention can prevent magnetic flux leakage, and thus eliminate unnecessary recording between tracks on a recording medium and eliminate errors during reproduction. , Its industrial effect is extremely large.

[Brief description of drawings]

FIG. 1 is an explanatory view of a holder of a multi-channel magnetic sensor according to the present invention viewed from a core surface.

FIG. 2 is an explanatory diagram showing an enlarged part of a recording stripe after development.

FIG. 3 is an explanatory view of a holder of a conventional multi-channel magnetic sensor as seen from a core surface.

FIG. 4 is an explanatory view of a holder of another conventional multi-channel magnetic sensor as viewed from the core surface.

[Explanation of symbols]

1, 1A, 1B: Holder 2, 2A, 2B: Core 3: Recessed 4: Inter-core gap material 5, 5A, 5B: Inter-channel shield plate 6, 6A, 6B: Inter-core spacer 7: Inter-shield gap material

Claims (1)

[Claims] 1. A multi-channel magnetic sensor comprising a plurality of front and rear pairs of cores on the left and right, wherein an inter-channel shield plate disposed between the cores and inter-core spacers on both sides of the inter-channel shield plate are the same as the cores. A multi-channel magnetic sensor, characterized in that it is arranged in front and rear in a pair, and a soft magnetic material is arranged between the front and rear abutting portions of the inter-channel magnetic shield plate.