JP2002183917A - Head drum device and magnetic recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of electrostatic breakdown of an MR head in a head drum device provided with the MR head. SOLUTION: A head substrate 33a and a protecting substrate 33b are formed to be such conductive that the electric resistance is not exceeding 1010 Ω, and by electrically connecting them with a base metal 36 by conductive pastes 39 and making them to the ground potential through the base metal 36 and a rotary drum 31, the electric charge is made to flow into the head substrate 33a and the protecting substrate 33b and discharged without flowing to an MR element 33c when an electrostatically charged magnetic tape 2 is brought into contact therewith.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head drum device for writing and reading signals to and from a magnetic tape and a magnetic recording / reproducing device having the same, and more particularly to a helical device using an MR head as a reproducing magnetic head. The present invention relates to a scan type head drum device and a magnetic recording / reproducing device including the same.

[0002]

2. Description of the Related Art In recent years, in a magnetic recording / reproducing apparatus for recording and reproducing data using a magnetic tape, it is desired to further improve the recording density with an increase in the amount of information to be handled. As a magnetic head,
Instead of the conventional inductive head, MR (Magneto Re
It is essential to use a sistive (magnetoresistive effect) head. An MR head is a magnetic head that reads a signal recorded on a magnetic recording medium using a magnetoresistance effect by an MR element, and has a high signal detection sensitivity.
Since a large reproduction output can be obtained, the recording track width on the magnetic tape can be easily reduced, the recording density in the linear direction can be increased, and high-density recording and reproduction can be performed.

As a recording / reproducing device using a magnetic tape, a helical scan for recording and reproducing signals by helically winding a magnetic tape around a head drum device which rotates together with a magnetic head provided on the outer periphery is known. The scheme is known. In this helical scan type recording / reproducing apparatus, the magnetic head slides on the running magnetic tape at a high speed to record and reproduce signals, so that the relative sliding speed between the magnetic tape and the magnetic head is high. An improvement in the data transfer rate has been realized.

[0004]

However, in general, MR
The head has a property that it is susceptible to static electricity and heat as compared with an inductive head. Here, FIG.
ESD (Electrostatic Discharge) in R head
4 shows the results of measuring the breakdown voltage. FIG. 7A shows the AMR (Anis
(otropic Magneto Resistive) head, (b) GMR
(Giant Magneto Resistive) The measurement result about a head is each shown.

In the measurement values shown in FIG. 7, an HBM (Human Body Model) is used in the measurement of the ESD breakdown voltage.
This shows the relationship between the voltage applied to the device and the resistance when discharging is performed with a resistance value of Ω. According to this, ES
D breakdown voltage is 230-240V for AMR head
And in the case of a GMR head, about 30 to 40 V. On the other hand, the charging voltage of an insulating object (plastic, nylon, vinyl, etc.) under a normal environment easily reaches several kV or more due to friction, contact, induction, etc. Exceed.

A conventional cassette case for winding and storing a magnetic tape is often formed of a high-resistance synthetic resin material. Such a cassette case is easily rubbed with, for example, artificial fiber packing material or gloves in the process of handling by a user, or rubbed with parts during loading on a magnetic recording / reproducing apparatus. Static electricity is charged. The charging voltage of the synthetic resin material used for the cassette case is, for example, 1500 to 2000 V or more for an ABS resin having a surface resistance of about 10 ¹⁶ Ω / sq, and the half-life is 3 minutes or more. Since the value of this charging voltage is much higher than the withstand voltage of the MR head, and the half-life is long, the charging once generated does not readily attenuate. For this reason, when the cassette case charged with static electricity is inserted into the magnetic recording / reproducing apparatus and a chance occurs that the magnetic tape comes into contact with the MR head, a large amount of current flows to the MR head via the magnetic tape, and the MR head becomes static. There is a risk of electrical breakdown.

FIG. 8 conceptually shows the flow of electric charges when the magnetic tape and the MR head come into contact with each other. Head drum device 80 provided in magnetic recording / reproducing device
Is, for example, a rotating drum 8 having a magnetic head on the outer peripheral surface.
2 and a fixed drum (not shown) which is fixed, and the magnetic tape 2 runs helically around the outer peripheral surface of the head drum device 80, and the magnetic head scans the magnetic tape 2 by the rotation of the rotary drum 82 By
Writing and reading of signals are performed. In FIG.
A part of the head drum device 80 is shown in an enlarged manner, and an MR head 81 is provided on a rotary drum 82 as a magnetic head for reading a signal, and a magnetic tape 2 running therethrough is provided.
To detect a recording signal.

When the cassette case around which the magnetic tape 2 is wound is charged with static electricity, as shown in FIG. 8, the surface of the magnetic tape 2 passes through the MR head 81 in contact with the magnetic tape 2 to the ground of the apparatus. This causes a flow of the charge 83 that flows. For example, at the start of the reproducing operation of the magnetic recording / reproducing apparatus, the cassette case is inserted into the magnetic recording / reproducing apparatus, and the magnetic tape 2 is brought closer to the rotating drum 82 by the movement of the guide mechanism, and the magnetic tape 2 contacts the MR head 81. At that moment, a large amount of current flows through the MR element, causing electrostatic breakdown of the MR element and making it impossible to read a signal. For this reason, conventionally, it has been difficult to use the MR head 81 as the magnetic head of the recording / reproducing apparatus using the magnetic tape 2.

The present invention has been made in view of such a problem, and an object of the present invention is to prevent occurrence of electrostatic breakdown of an MR head in a head drum device having the MR head.

It is another object of the present invention to prevent occurrence of electrostatic breakdown of an MR head in a magnetic recording / reproducing apparatus having an MR head.

[0011]

According to the present invention, in order to solve the above-mentioned problems, in a head drum device for writing or reading a signal to or from a magnetic tape, a head drum device having conductivity and a ground potential is provided. A rotating drum on which the magnetic tape is helically wound; a base metal fixed inside the rotating drum and electrically connected to the rotating drum; and a magnetoresistor for reading a recording signal by contacting the magnetic tape. A head element portion in which a head element as an effect element is disposed between a pair of magnetic shield films via a first and a second insulating film has an electric resistance of 1
0 ¹⁰ Ω or less, between the head substrate and the protection substrate, which are electrically connected to the base metal.
And a magnetic head portion fixed to the base metal and having a structure provided with the insulating film interposed therebetween.

In such a head drum device, the head substrate and the protection substrate are made conductive with an electric resistance of 10 ¹⁰ Ω or less, electrically connected to the base metal, and grounded via the base metal and the rotating drum. When the magnetic tape is charged with the electric potential, the electric charge flows into the head substrate and the protective substrate without discharging to the magnetoresistive effect (MR) element and is discharged. Destruction can be prevented.

According to the present invention, there is provided a magnetic recording / reproducing apparatus for recording and reproducing a signal using a magnetic tape.
A rotary drum having conductivity and ground potential, the magnetic tape being helically wound around the outer peripheral surface, a base metal fixed inside the rotary drum and electrically connected to the rotary drum, A head element, which is a magnetoresistive element that reads a recording signal in contact with the magnetic tape, is provided between a pair of magnetic shield films via a first and a second insulating film; Both have a structure in which an electric resistance is 10 ¹⁰ Ω or less and which is disposed via a third and a fourth insulating film between a head substrate and a protective substrate which are electrically connected to the base metal. A magnetic recording / reproducing apparatus comprising a head drum device having a magnetic head portion fixed to a base metal.

In such a magnetic recording / reproducing apparatus, in the head drum device, the head substrate and the protection substrate are made conductive with an electric resistance of 10 ¹⁰ Ω or less, and these are electrically connected to the base metal to form the base metal and the protection metal. By setting the ground potential via the rotating drum, when static electricity is charged on the magnetic tape, the charge is transferred to the magnetoresistive effect type (M
R) Since it flows into the head substrate and the protection substrate without discharging to the element and is discharged, it is possible to prevent electrostatic breakdown of the MR element.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 2 shows a schematic configuration example of a magnetic recording / reproducing apparatus including the head drum device of the present invention.

A magnetic recording / reproducing apparatus 1 shown in FIG. 2 uses a magnetic tape 2 as a recording medium, and is used, for example, as a data storage device of a computer device or a recording device for video signals and audio signals. FIG. 2 schematically shows a running system of the magnetic tape 2 during the recording or reproducing operation of the magnetic recording / reproducing apparatus 1. In FIG. 2, a magnetic recording / reproducing apparatus 1 includes a magnetic tape 2
A drum unit 3 for writing and reading signals to and from a capstan 4 and a pinch roller 5 for running the magnetic tape 2 at a predetermined speed;
And a plurality of tape guides (denoted as TG in the figure) 6a, 6b, 6c, 6d and 6e for assisting the traveling of the vehicle. The cassette case 7 inserted in the magnetic recording / reproducing apparatus 1 includes a supply reel 7a for the magnetic tape 2 and a take-up reel 7b.

In the magnetic recording / reproducing apparatus 1, when recording and reproducing of the magnetic tape 2 are performed, the cassette case 7 is inserted into the magnetic recording / reproducing apparatus 1 from below in FIG. It is held by a cassette mechanism (not shown), approaches the head drum device 3, and is lowered to a position where the pinch roller 5 and the TGs 6a to 6e are installed.
Thereafter, as the rotary drum of the head drum device 3 rotates, the pinch roller 5 and the TGs 6a to 6e move in the direction of arrow B in the drawing, so that the magnetic tape 2 winds around the head drum device 3 and the capstan 4 When the take-up reel 7b rotates, the magnetic tape 2
Travels to start writing or reading the recording signal.

Next, FIG. 3 is a perspective view showing a schematic configuration example of the head drum device 3. The head drum device 3 has a cylindrical shape having a smooth outer peripheral surface as a whole, and includes an upper rotating drum 31 and a fixed drum 32 fixed coaxially with the rotation axis of the rotating drum 31. Leads 32a for guiding the running of the magnetic tape 2 are provided on the outer peripheral surface of the fixed drum 32, whereby the magnetic tape 2 runs around the outer peripheral surface of the head drum device 3 in a helical manner. On the other hand, the rotating drum 31 is provided with a reproducing head device 33 for detecting a recording signal of the magnetic tape 2 and a recording head device (not shown) for writing a signal. The reproducing head device 33 is an MR head using a magnetoresistive effect (MR) element as a head element, and is provided so as to protrude slightly outward from the outer peripheral surface of the rotating drum 31 and contacts the magnetic tape 2. Then, the recording signal of the magnetic tape 2 is read by obliquely scanning the magnetic tape 2 by the rotation of the rotating drum 31 and detecting a change in the resistance value of the MR element according to the recording signal. The recording head device is a so-called inductive type magnetic head device in which a coil is wound around a magnetic core having a magnetic gap, for example. A plurality of reproducing head devices 33 and recording head devices are usually mounted on the rotating drum 31, but are not shown in FIG.

Next, FIG. 1 shows a plan view of the reproducing head device 33. FIG. FIG. 4 shows a side view of the reproducing head device 33. FIG. 1 is a view extracted from the direction of the arrow C shown in FIG. 3, that is, the state of the mounting portion of the reproducing head device 33 as viewed from below the head drum device 3, and FIG. A reproducing head device 33 viewed from the direction of arrow D shown in FIG.
Is shown. The configuration of the reproducing head device 33 will be described with reference to FIGS.

The reproducing head device 33 has a structure in which an MR element 33c and a pair of shield films 33d and 33e made of a soft magnetic material are arranged between a conductive head substrate 33a and a protective substrate 33b. . A head substrate 33a, a protection substrate 33b, and shield films 33d;
And 33e, insulating layers 33f and 33g are formed, and between shield films 33d and 33e, MR elements 33c are interposed via insulating films 33h and 33i.
Are formed to form a reproducing magnetic head portion. Such a reproducing head device 33 is connected to terminals 35a and 35b by conducting wires 34a and 34b and the like, whereby power is supplied to the reproducing head device 33. Further, as shown in FIG. 4, the reproducing head device 33 is fixed to a conductive base metal 36 with an adhesive 37, and the base metal 36 is fixed to the rotating drum 31 by a set screw 38 made of a conductor. ing. In FIGS. 1 and 4, the MR element 33c is shown large for easy understanding of the structure.
The R element 33c is much finer than the head substrate 33a and the protection substrate 33b.

In the reproducing head device 33, the shield films 33d and 33e constitute a pair of magnetic shield members, and the MR element 33c is disposed in a shield gap between the pair of magnetic shield members. As a result, the frequency characteristics and the resolution are improved. The shield films 33d and 33e are made of, for example, a permalloy plating film, and are formed of insulating films 33f to 33i.
Is made of, for example, Ai ₂ O ₃ ,
A reproducing head device 33 is formed by forming a thin film on 3a and joining the protective substrate 33b. Also,
In the reproducing head device 33, the rotating drum 31
An end surface facing outward (downward in FIG. 1) from the outer peripheral surface of the magnetic tape 2 is polished, and this end surface is a sliding surface of the magnetic tape 2.

By the way, as described above, the head substrate 3
3a and the protection substrate 33b are formed of a conductive material. Specifically, a resistance value of 10 at which static electricity is not charged
Is less ¹⁰ Omega, eg resistivity Al ₂ O ₃ -TiC and a ^{3 × 10 -3 Ω / cm,} MnZn ferrite or the like is used. The head substrate 33a and the protection substrate 3
The base metal 3 b is made of, for example, a conductive paste 39 or the like, separately from the bonding with the adhesive 37 such as an epoxy-based material.
6 is electrically connected. As the conductive paste 39, for example, silver paint is used. The base metal 36 is made of, for example, brass, and is fixed to the rotary drum 31 by a conductive metal set screw 38 and is electrically connected thereto. Further, the rotating drum 31 is formed of aluminum or the like, has conductivity, and has a ground potential.

FIG. 5 is a sectional view of the rotary drum 31. As shown in FIG. As shown in FIG. 5, for example, the rotary drum 31 has a spring 40 connected inside. The spring 40 is in contact with, for example, a chassis (not shown) serving as a ground of the magnetic recording / reproducing apparatus 1, thereby setting the rotating drum 31 to a ground potential. That is, the head substrate 33a and the protection substrate 33b are electrically connected to the rotating drum 31 at the ground potential in this way via the base metal.

As described above, the cassette case 7 in which the magnetic tape is wound up and stored is usually formed of a low-resistance synthetic resin material. Such a cassette case 7 is rubbed by, for example, a packing material of artificial fibers, gloves, or the like in a process of handling by a user, or is rubbed with parts at the time of loading on the magnetic recording / reproducing apparatus 1. Static electricity is easily charged. When the magnetic tape 2 housed in the cassette case 7 charged with the static electricity contacts the reproducing head device 33, a flow of electric charges is generated through the magnetic tape 2, through the MR element 33c, and to the ground of the device. , MR element 33
c causes electrostatic breakdown.

In order to prevent this, in the head drum device 3 of the present invention, the head substrate 33a and the protection substrate 33
b is a material having conductivity, and the head substrate 33a and the protection substrate 33b are electrically connected to the ground of the apparatus by the conductive paste 39, the base metal 36, and the set screw 38 between the base metal 36 and the rotating drum 31. Thus, at the time of contact between the magnetic tape 2 and the reproducing head device 33, a flow of electric charge which does not pass through the MR element 33c is provided.

FIG. 6 conceptually shows the flow of electric charges in the head drum device 3. For example, at the start of the reproducing operation of the magnetic tape 2 in the magnetic recording and reproducing apparatus 1, first, the cassette case 7 is inserted into the magnetic recording and reproducing apparatus 1, the rotating drum 31 rotates, and the magnetic tape 2 is moved by the movement of the guide mechanism. It is wound near the rotating drum 31 and loading is performed. At this time, when the magnetic tape 2 comes into contact with the reproducing head device 33, as shown in FIG. 6, the electric charge due to the static electricity accumulated in the cassette case 7 does not pass through the MR element 33c, and Flows from the surface to the head substrate 33a and the protection substrate 33b, and to the ground of a device such as an electrically connected chassis. The area of the MR element 33c on the sliding surface of the magnetic tape 2 is smaller than that of the head substrate 33a and the protection substrate 33b.
Is in contact with the head substrate 33a or the protection substrate 33b, the current flows into the head substrate 33a or the protection substrate 33b, and the current flows into the head substrate 33a or the protection substrate 33b. . Therefore, when the cassette case 7 is charged with static electricity,
The occurrence of electrostatic breakdown of the MR element 33c is prevented,
The reproducing operation of the magnetic tape 2 can be performed normally.

In the reproducing head device 33 described above,
Both the head substrate 33a and the protection substrate 33b were made conductive, but either of them was made conductive, that is, the electrical resistance was 10 ¹⁰ Ω.
It may be formed of the following materials.

In the above description, an example in which the head drum device of the present invention is provided in a magnetic recording / reproducing apparatus using a magnetic tape has been described. However, the present invention is applied to a magnetic reproducing apparatus capable of reproducing only a magnetic tape. It is also possible.

[0029]

As described above, in the head drum device according to the present invention, the head substrate and the protection substrate are made to be conductive with an electric resistance of 10 ¹⁰ Ω or less, and these are electrically connected to the base metal to form the base substrate. By setting the ground potential via the metal and the rotating drum, when static electricity is charged on the magnetic tape, the charge does not flow to the magnetoresistive effect (MR) element but flows to the head substrate and the protective substrate and is discharged. Therefore, it is possible to prevent electrostatic breakdown of the MR element.

Further, in the magnetic recording / reproducing apparatus of the present invention, in the head drum device, the head substrate and the protective substrate are made to be conductive with an electric resistance of 10 ¹⁰ Ω or less, and these are electrically connected to the base metal to form a base. By setting the ground potential via the metal and the rotating drum, when static electricity is charged on the magnetic tape, the charge does not flow to the magnetoresistive effect (MR) element but flows to the head substrate and the protective substrate and is discharged. Therefore, it is possible to prevent electrostatic breakdown of the MR element.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a reproducing head device.

FIG. 2 is a diagram illustrating a schematic configuration example of a magnetic recording / reproducing apparatus including a head drum device of the present invention.

FIG. 3 is a perspective view showing a schematic configuration example of a head drum device of the present invention.

FIG. 4 is a side view showing a configuration of a reproducing head device.

FIG. 5 shows a sectional view of a rotating drum.

FIG. 6 is a diagram conceptually showing a flow of charges in the head drum device of the present invention.

FIGS. 7A and 7B are diagrams showing measurement results of an ESD breakdown voltage in an MR head, wherein FIG. 7A shows a measurement result for an AMR head, and FIG.

FIG. 8 is a diagram conceptually showing a flow of charges when a magnetic tape and an MR head come into contact with each other.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic recording / reproducing apparatus, 2 ... Magnetic tape, 3 ... Head drum device, 4 ... Capstan, 5 ... Pinch roller, 6a-6e ... Tape guide, 7 ... Cassette case, 7a ... Supply reel, 7b ... take-up reel,
31 rotating drum, 32 fixed drum, 33 reproducing head device, 33a head substrate, 33b protection substrate, 33c MR element, 33d, 33e shielding film, 33f, 33g, 33h, 33i ... insulating film,
34a, 34b ... lead wire, 35a, 35b ... terminal, 3
6 Base metal 37 Adhesive 38 Set screw 39 Conductive paste 40 Spring

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Katsuhiro Kasuga, Inventor 30th Kagano Border, Takami Niida, Nakata-cho, Tome-gun, Miyagi Prefecture Sony Miyagi Co., Ltd. F-term (reference) 5D034 BA02 BA16 BB05 BB08 CA07 5D036 AA07 BB02 CC93 FF01 FF02 FF04

Claims (5)

[Claims] 1. A head drum device for writing or reading a signal to or from a magnetic tape, comprising: a rotary drum having a ground potential having conductivity, wherein the magnetic tape is helically wound around an outer peripheral surface; A base metal fixed inside the rotating drum and electrically connected to the rotating drum, and a head element serving as a magnetoresistive element for reading a recording signal in contact with the magnetic tape are disposed between a pair of magnetic shield films. A head element portion disposed between the head substrate and the protection substrate having an electric resistance of 10 ¹⁰ Ω or less and electrically connected to the base metal. A magnetic head portion having a structure disposed via third and fourth insulating films, and having a magnetic head portion fixed to the base metal. Beam apparatus. 2. The method according to claim 1, wherein the head substrate and the protection substrate are A
l ₂ O ₃ -TiC or head drum apparatus according to claim 1, characterized in that it is formed by the MnZn ferrite. 3. The head substrate and the protection substrate,
The head drum device according to claim 1, wherein the base metal is connected to the base metal by a conductive paste. 4. The semiconductor device according to claim 1, wherein one of the head substrate and the protection substrate has an electric resistance of 10 ¹⁰ Ω or less and is electrically connected to the base metal.
The head drum device as described in the above. 5. A magnetic recording / reproducing apparatus for recording and reproducing signals by using a magnetic tape, comprising: a rotating drum having conductivity and ground potential, and the magnetic tape being helically wound around an outer peripheral surface; A base metal fixed inside the rotating drum and electrically connected to the rotating drum; and a head element, which is a magnetoresistive element that reads a recording signal in contact with the magnetic tape, includes a pair of magnetic shield films. A head element portion provided with a first and a second insulating film interposed therebetween has a head substrate and a protection substrate each having an electric resistance of 10 ¹⁰ Ω or less and electrically connected to the base metal. And a magnetic head portion fixed to the base metal and having a structure disposed between the third and fourth insulating films. Magnetic recording and reproducing apparatus according to symptoms.