JP2002025148A - Magnetic recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an adverse effect to a magnetic head caused by static electricity charged to a magnetic tape. SOLUTION: This magnetic recording/reproducing device 1 includes plural magnetic heads 4a and 4b, and records/reproduces data on a magnetic tape 13 as a recording medium by a rotary head drum 3 rotated by a drum motor 8. In this case, the device 1 is provided with a magnetic head phase control means 16 for controlling the position of the magnetic head during tape loading. When the rotary head drum is brought into first contact with the magnetic tape during tape loading, the metal part of the rotary head drum is first brought into contact with the magnetic tape by the magnetic head phase control means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for protecting a magnetic head in a magnetic recording / reproducing apparatus from the influence of static electricity charged on a magnetic tape as a recording medium.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus for recording or reproducing data on a magnetic tape as a recording medium by using a rotary head drum on which a plurality of magnetic heads are mounted, recently,
In order to further improve the recording density of information signals and increase the amount of recordable information per volume of recording tape, shorter recording wavelengths, narrower recording track widths, thinner magnetic tapes, and the like have been developed. I have.

In a commonly used inductive magnetic head, when the recording wavelength is shortened or the recording track width is narrowed, the level of a reproduced signal is reduced, and the S / N ratio is reduced.
(Signal to Noise Ratio) cannot be obtained sufficiently, so that an MR (Magnet R) having a higher output signal level
esistance (magnetoresistive effect) It is conceivable to use a head.

However, MR heads have a drawback that they are susceptible to electrostatic breakdown. For example, the characteristics are easily deteriorated by static electricity of several tens to several hundreds of volts charged on a magnetic tape, or they are destroyed in severe cases. There was a thing.

[0005] Some magnetic tapes are provided with a conductive back coating in order to prevent the base material on which the magnetic material is applied from being charged. However, it cannot be neglected for those affected by static electricity of mud voltage such as MR head.

FIGS. 11 to 13 schematically show the state of each part during tape loading in a conventional magnetic recording / reproducing apparatus.
Are shown in order.

That is, the magnetic recording / reproducing apparatus a includes a rotary head drum c disposed on a mechanical deck b, magnetic heads d and d mounted on the rotary head drum c, tape guides e, f, g, h, and a cap. It has a stun i and a pinch roller j. The tape cassette k has a state in which the magnetic tape n is wound between the supply reel 1 and the take-up reel m.

In the magnetic recording / reproducing apparatus a, the tape cassette k shown in FIG. 11 is simply mounted on the mechanical deck b. In a state immediately before tape loading is started, the magnetic tape n is different from the rotating head drum c. Not in contact.

Next, when the magnetic tape n is pulled out from the tape cassette k by the tape guides e, f, g, h, etc., and the tape loading is started, as shown in FIG. It comes into contact with the rotating head drum c.

Then, as shown in FIG. 13, the magnetic tape n is wound around the rotary head drum c by a predetermined angle to complete the tape loading, but the effect of the static electricity charged on the magnetic tape is as follows. When a part of the magnetic tape n comes into contact with the rotary head drum c during tape loading, a problem arises when one of the magnetic heads d is accidentally located at a position where it contacts the magnetic tape as shown in FIG. Becomes In such a case, the static electricity charged on the magnetic tape n is discharged to the magnetic head d, and when an MR head is used as the magnetic heads d, the characteristics may be deteriorated or destroyed. Was.

In the magnetic recording / reproducing apparatus a, when the rotating head drum c is in a state in which the magnetic heads d and d are stopped at an arbitrary position or in a state where they continue to rotate as shown in FIG. Therefore, the positions of the magnetic heads d and d when the magnetic tape n comes into contact with the rotary head drum c are indeterminate.

Therefore, depending on the position of the magnetic heads d, d when the charged magnetic tape n comes into contact with the rotary head drum c, discharge occurs from the magnetic tape n to the magnetic head d, thereby deteriorating the characteristics or destruction. The danger of being done comes with it.

[0013]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to prevent adverse effects on a magnetic head due to static electricity charged on a magnetic tape.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of recording data on a magnetic tape, which is a recording medium, by a rotating head drum mounted with a plurality of magnetic heads and rotated by a drum motor. In a magnetic recording / reproducing apparatus for performing reproduction, a magnetic head phase control means for controlling a position of a magnetic head at the time of tape loading is provided. Thus, the metal portion of the rotary head drum is brought into contact with the magnetic tape first.

Therefore, when the magnetic tape is charged with static electricity, it can be discharged by contact with the metal part of the rotary head drum.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the magnetic recording / reproducing apparatus of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 to 3, a magnetic recording / reproducing apparatus 1 includes a rotary head drum 3 disposed on a mechanical deck 2 and a magnetic head 4 mounted on the rotary head drum 3.
a, 4b, tape guides 5a, 5b, 5c, 5d, a capstan 6, a pinch roller 7, and the like.

As shown in FIG. 4, the rotary head drum 3 has a rotary drum 3a, a fixed drum 3b, a drum motor 8, etc. The drum motor 8 and the rotary drum 3a are connected by a rotary shaft 3c. The rotation of the motor 8 is transmitted to the rotating drum 3a to rotate the rotating drum 3a.

The magnetic heads 4a and 4b mounted on the rotating drum 3a of the rotating head drum 3 and recording or reproducing data on or from a magnetic tape as a recording medium are positioned on the outer periphery of the rotating head drum 3 at, for example, 180.degree. Are located in

The magnetic heads 4a and 4b are provided with an MR (Magnet Resistor) in order to improve the data recording density, shorten the recording wavelength, and narrow the recording track width.
A so-called MR head is used in which an effect element is used for a magnetic sensing part, a change in magnetism on a magnetic tape is replaced by a change in resistance of an MR film, and this is taken out as a change in current.

When an MR head is used as the magnetic heads 4a and 4b, the recording head must be mounted on the rotating drum separately from the magnetic heads 4a and 4b because the MR head is usually used only for reproduction. However, illustration and description of the recording head are omitted. In general, a pair of magnetic heads 4a and 4b having two types of azimuth angles are mounted on a rotating drum 3a as a magnetic head as a reproducing head.

When the tape cassette 9 is not loaded in the magnetic recording / reproducing apparatus 1 as shown in FIGS. 1 to 3, a magnetic tape is provided between the supply reel 11 and the take-up reel 12 inside the case body 10. 13 has been bridged.

The tape guides 5a, 5b, 5c and 5d and the pinch roller 6 are driven by a drive mechanism (not shown) and can be moved on the mechanical deck 2 in a direction approaching the rotary head drum 3.

Accordingly, when the tape guides 5a, 5b, 5c and 5d and the pinch roller 7 are in a state where only the tape cassette 9 is loaded, as shown in FIG. Then, when the tape loading is started from this state, as shown in FIG. 2 and FIG. 3 in order, the tape is horizontally moved in a direction approaching the periphery of the rotary head drum 3 and the supply reel 11 is moved inside the case body 10.
The magnetic tape 13 that has been wound between the take-up reel 12 and the take-up reel 12 is pulled out to the outside, and is wound around the outer peripheral surface of the rotary head drum 3 at a predetermined angle as shown in FIG. It moves so as to be sandwiched between the pinch roller 7. by this,
The magnetic tape 13 can run along a tape path defined by a part of the outer peripheral surface of the rotary head drum 3, the tape guides 5a, 5b, 5c, 5d, the capstan 6, the pinch roller 7, and the like.

As described above, the rotary drum 3a of the rotary head drum 3 is driven by the drum motor 8 to rotate. As schematically shown in FIG. 5, the drum motor 8 has stator coils 14U, 14 each having a three-phase structure of U, V, and W phases, each of which is arranged 120 ° apart.
As shown in FIG. 6, the motor is a three-phase motor having rotor magnets 15 in which V poles, 14 W poles, and S poles and N poles are alternately arranged at intervals of 60 °. As the rotor magnet, other than the rotor magnet 15, it is also possible to use a rotor magnet 15A shown in FIG.

The drum motor 8 rotates the rotor 8b having the rotor magnet 15 by supplying three-phase AC power as shown in FIG. 8 to the stator coils 14U, 14V and 14W of the stator 8a. And the drum 3 connected by the rotating shaft 3c
Rotate a.

As described above, the magnetic heads 4a and 4b are MR heads having a drawback of being susceptible to electrostatic breakdown as described above.

Therefore, in the magnetic recording / reproducing apparatus 1, in order to protect the magnetic heads 4a and 4b from the discharge phenomenon due to the static electricity charged on the magnetic tape 13, the rotating head drum 3 comes into contact with the magnetic tape 13 at the time of tape loading. At this time (hereinafter referred to as “initial contact”), the magnetic tape 13
Is brought into contact with a metal portion of the rotary head drum 3 other than the portion where the magnetic heads 4a and 4b are fixed, and the magnetic tape 1
A magnetic head phase control means 16 is provided to discharge the static electricity from the metal part 3 to the metal parts so as not to affect the magnetic heads 4a and 4b.

The magnetic head phase control means 16 determines the position of the magnetic heads 4a and 4b on the circumference of the rotary head drum 3, that is, the positional relationship between the magnetic tape 13 and the magnetic heads 4a and 4b at the time of initial contact. A motor driver 1 for controlling the rotation of the drum motor 8
7, the rotation of the rotor 8b is controlled by the magnetic heads 4a, 4b.
Can be stopped so as to reach a predetermined position (phase).

As shown in FIG. 9, the motor driver 17 normally controls the stator coils 14 U, 14 V, 14 V by a motor control circuit 18.
8 so that the voltage phase of each phase of W is shifted by 120 °.
By supplying AC power having the waveform shown in FIG.
Is rotating.

Here, when the switch SW1 is turned on,
U-phase, V-phase and W-phase stator coils 14
The transistors TR1 to TR7 that supply voltages to the U, 14V and 14W are all turned off, the rotor 8b and the rotating drum 3a enter a free rotation state, and then stop at an appropriate position. , Ie, the phase is indefinite.

When the switch SW2 is turned on together with the switch SW1 being turned on, the voltage is supplied only to the U-phase stator coil 14U, and there are three locations in the U-phase stator coil 14U and the rotor 8b. The rotation of the rotor 8b is stopped in a state where one of the N poles (or S poles) is opposed, and the phases of the magnetic heads 4a and 4b fixed to the rotating drum 3a can be specified at intervals of 120 °. become.

When the rotor magnet 15A shown in FIG. 7 is used for the rotor 8b, a U-phase stator coil 14U and six N-poles (or S-poles) are provided.
The rotation of the rotor 8b is stopped in a state where any one of
The phases of a and 4b are specified every 60 °.

In the example of the motor driver 17 shown in FIG. 9, the U-phase stator coil 14U is used to specify the phases of the magnetic heads 4a and 4b. Stator coils 14V, 14
It is also possible to use W.

When the rotor magnet 15 or 15A is stopped at a specific position by the magnetic head phase control means 16, the following configuration is required to specify the positional relationship between the rotor magnet 15 and 15A and the magnetic heads 4a and 4b. It is.

That is, U, V and W-phase stator coils 14U, 14V, 1
In addition to energizing only a specific phase of 4W, U phase, V
Phase or W phase stator coils 14U, 14V, 14W
Is a position where the rotary head drum 3 first contacts the magnetic tape 13 during tape loading, that is, the position indicated by 19 in FIGS. 2 and 10, ie, the rotary head drum 3 and the magnetic tape 13 needs to be arranged at a position shifted by at least 45 ° from the position where it first contacts.

As shown in FIGS. 6 and 7, the magnetic heads 4a and 4b arranged and fixed on the rotary drum 3a of the rotary head drum 3 are arranged such that the rotary drum 3a and the rotor magnet 15 or 15A are planarly arranged. In view of this, it is necessary to arrange the drawer magnet 15 or 15A so as to be between two adjacent magnetic poles.

During the initial contact between the magnetic tape 13 and the rotary head drum 3, the control positions of the magnetic heads 4a and 4b on the rotary drum 3a whose phases are fixed by the magnetic head phase control means 16 are as follows. As shown in FIG. 10, the position is one of three positions at intervals of 120 ° in the figure.
When the rotor 15A is used for the rotor 8b, in addition to the above three positions, these magnetic heads 4a are used.
60 ° with three positions where the positions of 4b and 4b are reversed
There are six other positions.

As described above, in the magnetic recording / reproducing apparatus 1, at the time of the initial contact between the magnetic tape 13 and the rotary head drum 3, the magnetic heads 4a, 4a,
It becomes possible to stop the rotating drum 3a so that b is at a specific position avoiding the contact portion 19.

Therefore, even when the magnetic tape 13 is charged with static electricity, the magnetic tape 13 first contacts the metal outer peripheral portion of the rotary head drum at the contact portion 19, and the static electricity is discharged. , Magnetic heads 4a, 4b
In this way, it is possible to eliminate the adverse effects of discharging static electricity.

As described above, the magnetic head phase control means 16 does not add a new mechanism, but has a simple structure in which the structures of the existing drum motor 8 and motor driver 17 are partially changed. As a result, it is possible to prevent the cost of the magnetic recording / reproducing apparatus from being significantly increased and the mechanism from being complicated.

In the embodiment described above, the magnetic head is arranged at a position 180 ° apart. However, even when the arrangement of the magnetic head is not 180 °, the magnetic tape and the rotating head drum can be used. Considering the stop position of each magnetic head at the time of initial contact with
If the positions of the magnetic poles of the magnetic head and the rotor magnet and the position of the stator coil of the drum motor are appropriately arranged, as in the case of the above embodiment, at the time of the initial contact between the magnetic tape and the rotary head drum, the magnetic tape becomes magnetic. It is possible to avoid contact with the head.

It should be noted that the specific shapes and structures of the respective parts shown in the above-described embodiment are merely examples for embodying the present invention, and the technical features of the present invention will be described below. The scope should not be construed as limiting.

[0044]

As described above, the magnetic recording / reproducing apparatus of the present invention has a plurality of magnetic heads mounted thereon and records or reproduces data on or from a magnetic tape as a recording medium by a rotating head drum rotated by a drum motor. The magnetic recording / reproducing apparatus has a magnetic head phase control means for controlling the position of the magnetic head at the time of tape loading, and when the rotating head drum first comes into contact with the magnetic tape at the time of tape loading, the magnetic head phase control means Since the metal portion of the rotary head drum is brought into contact with the tape first, it is possible to prevent the magnetic head from being affected by the discharge of static electricity charged on the magnetic tape.

According to the second aspect of the present invention, the magnetic head phase control means selectively controls one of the stator coils by a control circuit of the drum motor for driving the rotary head drum. To stop the rotation of the rotary head drum at a predetermined position so as to prevent the magnetic head from contacting the magnetic tape. Can be prevented from significantly increasing the cost and complicating the mechanism.

According to the third aspect of the present invention, when the tape is loaded, the rotating head drum first contacts the magnetic tape so that the rotating head drum can be stopped at a position where the magnetic head does not contact the magnetic tape. Place the stator coil of the drum motor that drives the rotary head drum avoiding the contact position when making contact, and make sure that the position of the magnetic head on the rotary head drum corresponds to the position of the magnetic pole of the rotor magnet of the drum motor. With this arrangement, the magnetic head can be stopped at a specific position avoiding the position where the rotary head drum and the magnetic tape first contact each other during tape loading with a simple structure change.

According to the fourth aspect of the present invention, an MR (magnetoresistive) head is used as a reproducing magnetic head.
It is possible to cope with a shorter recording wavelength and a narrower recording track width.

[Brief description of the drawings]

FIG. 1 shows, together with FIG. 2 and FIG. 3, a positional relationship between a magnetic tape and a rotary head drum during tape loading in a magnetic recording and reproducing apparatus of the present invention, and this figure shows a state immediately before tape loading starts. It is a top view.

FIG. 2 is a plan view showing a state where a magnetic tape first contacts a rotary head drum during tape loading.

FIG. 3 is a plan view showing a state at the time of tape loading completion.

FIG. 4 is an enlarged sectional view schematically showing a rotary head drum.

FIG. 5 is a diagram schematically showing a structure of a drum motor.

FIG. 6 is a diagram schematically showing a structure of a rotor magnet and a positional relationship with a magnetic head.

FIG. 7 is a diagram schematically showing a structure of a modified example of a rotor magnet and a positional relationship with a magnetic head.

FIG. 8 is a diagram showing a waveform of AC power applied to a stator coil of a drum motor.

FIG. 9 is a diagram schematically showing a structure of a motor driver for controlling rotation of a drum motor.

FIG. 10 is a diagram showing the position (phase) of the magnetic head controlled by the magnetic head phase control unit when the magnetic tape first contacts the rotary head drum during tape loading.

11 and 12 together with FIG. 12 and FIG. 13 show the positional relationship between the magnetic tape and the rotating head drum during tape loading in the conventional magnetic recording and reproducing apparatus, and FIG. 11 shows a state immediately before tape loading starts. It is a top view.

FIG. 12 is a plan view showing a state where a magnetic tape first contacts a rotary head drum during tape loading.

FIG. 13 is a plan view showing a state at the time of tape loading completion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic recording / reproducing apparatus, 3 ... Rotating head drum, 4a ...
Magnetic head, 4b: magnetic head, 8: drum motor,
13: magnetic tape, 14: stator coil, 16: magnetic head phase control means, 17: drum motor control circuit

Claims (4)

[Claims] 1. A magnetic recording / reproducing apparatus having a plurality of magnetic heads mounted thereon and recording or reproducing data on or from a magnetic tape as a recording medium by a rotary head drum rotated by a drum motor. A magnetic head phase control means for controlling the position of the magnetic head, and when the rotary head drum first comes in contact with the magnetic tape during tape loading, the magnetic head phase control means causes the metal part of the rotary head drum to be attached to the magnetic tape. A magnetic recording / reproducing apparatus, wherein the magnetic recording / reproducing apparatus is contacted first. 2. A magnetic head phase control means for selectively energizing one of stator coils to a drum motor for driving a rotary head drum by a control circuit of the drum motor. 2. The method according to claim 1, wherein the rotation is stopped at a predetermined position so that the magnetic head does not contact the magnetic tape.
3. The magnetic recording and reproducing device according to claim 1. 3. The rotating head drum rotates while avoiding the contact position where the rotating head drum first contacts the magnetic tape during tape loading so that the rotating head drum can be stopped at a position where the magnetic head does not contact the magnetic tape. 3. A method according to claim 2, further comprising arranging a stator coil of a drum motor for driving the head drum, and arranging a position of a magnetic head on the rotary head drum so as to correspond to a position of a magnetic pole of a rotor magnet of the drum motor. 3. The magnetic recording and reproducing device according to claim 1. 4. The magnetic recording / reproducing apparatus according to claim 1, wherein an MR (magnetoresistive) head is used as the reproducing magnetic head.