JPH0778318A - Rotary head device - Google Patents

Abstract

PURPOSE:To realize a rotary head device capable of obtaining the satisfied head touch in between a magnetic tape and a magnetic head in respect to a magnetic recording/reproducing device. CONSTITUTION:The magnetic head 6 is mounted on the notched part 8 of a rotary drum 2. A charged body 12 is provided on the outer peripheral part of the magnetic head 6 through a conductive material 13. During the rotation of the rotary drum 2, the magnetic tape 5 is attracted by the charged body 12 due to the static electricity, then the thickness of an air layer formed between the magnetic tape 5 near the magnetic head 7 and the rotary drum 2 is made thinner. By such a manner, the contact resistance between the rotary drum 2 and the magnetic tape 5 is suppressed to the minimum without increasing the tape tension. Also, the satisfactory contact is obtained, and an output of the reproduced signal becomes uniform. By arranging the conductive material 13 between the magnetic head 6 and the charged body 12, the static electicity induced on a rotary shaft is lead out to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head device used in a magnetic recording / reproducing device such as a VTR or a digital audio device.

[0002]

2. Description of the Related Art A conventional rotary head device will be described with reference to FIGS. FIG. 3 is an external view showing the configuration of a conventional rotary head device. In this figure, the rotary head device 1
Includes a rotating drum 2 (also referred to as a rotor) and a fixed drum 3. The rotary drum 2 is rotatably held coaxially with the fixed drum 3 via a slit 4. The magnetic tape 5, which is a recording medium, is wound around the rotary head device 1 at a predetermined angle. A magnetic head 6 is attached to a side surface of the rotary drum 2 facing the fixed drum 3.

FIG. 4 is a partially enlarged view showing the structure around the magnetic head 6 fixed to the rotary drum 2. Further, FIG. 5 is a perspective view showing the mounting state of the magnetic head 6 with the rotary drum 2 being inverted. As shown in FIG. 4, the front surface of the magnetic core serves as a sliding surface 7, and the magnetic head 6 is mounted so as to contact the magnetic tape 5 so as to protrude from the notch portion 8 of the rotary drum 2 by a predetermined amount. The magnetic head 6 is provided with a magnetic gap 9 so that information can be recorded on the magnetic tape 8 by the magnetic flux excited by the coil.

[0004]

When the rotary drum 2 rotates, air is entrapped between the magnetic tape 5 and the rotary drum 2 to form an air layer. Therefore, the magnetic tape 5 floats above the rotary drum 2. In general, as the rotating speed of the rotating drum 2 increases, the width of the magnetic tape 5 increases, the thickness of the magnetic tape 5 decreases, the rigidity of the tape decreases, and the tape tension decreases. The air inflow amount between the tapes 5 increases. If the flying height of the magnetic tape 5 with respect to the rotating drum 2 increases too much, the contact state between the magnetic tape 5 and the magnetic head 6 deteriorates, and there is a problem that good signals cannot be transmitted and received.

Therefore, the rotary head device 1 as in the conventional example.
In order to obtain a good contact state with the magnetic tape 5, it is necessary to ensure that the tape tension on the tape entry side of the rotary head device 1 is large to some extent. In this case, the power consumption of the capstan motor for running the magnetic tape 5 increases. Further, in the rotary head device 1, since the magnetic tape 5 is spirally wound around the rotary drum 2, the width of the magnetic tape 5 facing the rotary drum 2 sequentially changes at the circumferential position of the rotary drum 2. . Therefore, the flying height of the magnetic tape 5 increases on the entry side of the magnetic tape 5 and decreases on the exit side thereof with respect to the rotating direction of the rotary drum 2. Therefore, when the operation mode of the magnetic recording / reproducing apparatus is in the reproducing state, the reproduction output of the magnetic head 6 tends to be small on the entry side of the magnetic tape 5 and large on the exit side.

Such non-uniformity of the reproduced signal makes it difficult to determine the amplification factor of the reproduced signal.
This is because, if the amplification factor of the head amplifier is adjusted when the reproduction output of the magnetic head 6 is the minimum, the reproduction output of the magnetic head 6 becomes maximum on the exit side of the magnetic tape 5, so that the head amplifier may be saturated. is there. On the contrary, if the amplification factor of the head amplifier is adjusted when the reproduction output of the magnetic head 6 is maximum, the reproduction output of the magnetic head 6 is minimized on the entry side of the magnetic tape 5, so that the reproduction signal is sufficiently amplified. In addition, it may cause image deterioration. As described above, the nonuniformity of the reproduction signal causes a problem that the design of the head amplifier becomes difficult.

FIG. 6 is an explanatory view schematically showing the floating state of the magnetic tape 5 in the vicinity of the cutout portion 8. As shown in this figure, since a uniform air layer is not formed in the cutout portion 8,
The flying height of the magnetic tape 5 is locally reduced. Therefore, as shown by the arrow, the magnetic tape drop portions A and B are formed before and after the cutout portion 8. As described above, in the notch 8 on the entry side where the flying height of the magnetic tape 5 is large, the reduction in the distance between the magnetic head and the magnetic tape has the effect of increasing the reproduction output. However, in the notch 8 on the exit side where the flying height of the magnetic tape is small, there is a problem that the magnetic tape 5 and the rotating drum 2 come into contact with each other as the flying height of the magnetic tape 5 decreases. In particular, this phenomenon is remarkable in the portion indicated by the depression B on the rear side in the rotation direction of the rotary drum 2. If the local deformation of the magnetic tape 5 in the vicinity of the cutout portion 8 is large, the magnetic tape 5 is easily damaged, and the durability and reliability of the magnetic tape 5 are deteriorated. Magnetic tape 5
Locally contacts the rotating drum 2 or the fixed drum 3 to damage the rotating drum 2 or the fixed drum 3,
Further, there is a problem in that the rotation resistance of the rotary drum 2 is also generated due to the frictional resistance of the contact portion, and image jitter is generated.

The present invention has been made in view of the above-mentioned problems of the related art, and in a magnetic recording / reproducing apparatus, a reproduction signal can be obtained by obtaining good contact between a magnetic tape and a magnetic head with a simple structure. It is an object of the present invention to provide a rotary head device capable of stabilizing the envelope of.

[0009]

SUMMARY OF THE INVENTION The present invention comprises a stationary drum,
A rotary head device that is rotatably held coaxially with a fixed drum and that includes a rotary drum having a magnetic head provided in a cutout portion, wherein at least one of the rotary drum in the vicinity of the magnetic head is in the rotation direction or the rotation axis direction, It is characterized in that a charging body is provided.

[0010]

According to the present invention having such characteristics, the magnetic tape is disposed on the outer peripheral surface of the rotating drum by disposing the charging member in at least one of the rotating direction and the rotating shaft direction of the rotating drum near the magnetic head. When running, the charged body attracts the peripheral portion of the magnetic head due to static electricity. Therefore, the contact state between the magnetic tape and the magnetic head becomes stable, and the output of the reproduction signal becomes uniform. Further, the running magnetic tape does not damage the rotating drum and the fixed drum.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary head device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a partial front view showing a main structure of a rotary head device 11 of the present embodiment, and FIG. 2 is a partial cross-sectional view of the rotary head device 11 cut in parallel with a bottom surface of a rotary drum 2. In FIG. 1, the rotary head device 11 has a rotary drum 2 and a fixed drum 3 similar to those of the conventional example. Rotating drum 2 is fixed drum 3
On the other hand, it is rotatably supported via the gap of the slit 4. The magnetic tape 5 as a recording medium is a rotary head device 1.
It is wound around 1 at a predetermined angle. Similar to the conventional example, the magnetic head 6 is fixed to the cutout portion 8 of the rotary drum 2 with a screw or the like, and the magnetic head 6 is placed on the circumferential surface of the rotary drum 2 so that the sliding surface 7 of the magnetic core contacts the magnetic tape 5. Only a certain amount is outstanding. Therefore, as the rotary drum 2 rotates, the sliding surface 7 of the magnetic head 6 contacts the magnetic tape 5,
Signals are recorded and reproduced on the magnetic tape 5.

A charging body 12 is provided in the cutout portion 8 so as to surround the magnetic head 6 in at least one of the rotational direction of the rotary drum 2 and the coaxial direction with the fixed drum 3. A voltage is applied to the charging body 12 from a circuit (not shown), and the magnetic tape 5 is attracted by static electricity. As shown in FIG. 2, the outer peripheral surface of the charged body 12 is supported in a shape along the arc surface of the magnetic head 6. Further, the outer peripheral surface of the charging body 12 is formed so as to protrude by a predetermined amount in the radial direction of the outer peripheral surface of the rotary drum 2 within a range in which it does not protrude from the tip of the magnetic head 6. A magnetic gap 9 is provided in the magnetic head 6.

As shown in FIG. 1, a conductor 13 is provided between the outer peripheral portion of the magnetic head 6 and the inner peripheral portion of the charging body 12.
Depending on the magnitude of the DC voltage applied to the charging body 12, static electricity generated when the magnetic tape 5 is scanned is generated by the rotary head device 1.
Discharge to the rotating shaft of. In this case, the magnetic head 6 may be affected by this discharge current and generate speckle noise on the reproduction screen. For this reason, a shield conductor 13 may be provided to prevent the magnetic head 6 from being affected by noise generated by the discharge of electric charges generated between the charging body 12 and the magnetic tape 5.

The rotary head device 1 configured as described above
1, the magnetic head 6 rotates with the rotation of the rotary drum 2.
Scans the magnetic tape 5. The magnetic tape 5 runs while slidingly contacting the outer peripheral surface of the rotary drum 2. That is, the running magnetic tape 5 comes into contact with the tip of the magnetic head 6 and the outer peripheral surface of the charging body 12 surrounding the head. A DC voltage is applied to the charging body 12 to generate static electricity. The magnetic tape 5 is attracted to the magnetic head 6 by this electrostatic force. Since this attracting force changes depending on the tape thickness of the magnetic tape 5, the contact between the magnetic tape 5 and the magnetic head 6 can be optimized by changing the value of the DC voltage.

It should be noted that the conductor 13 need not be provided when the noise due to the discharge charge is small. Further, the arrangement shapes of the charging body 12 and the conductor 13 are not limited to those described above.

[0016]

As described above, according to the present invention, the magnetic head improves the close contact between the magnetic tape and the magnetic head in the rotary head device by the attracting action of the charged body provided on the outer peripheral portion of the magnetic head. Therefore, the output of the reproduction signal becomes uniform on all the sliding surfaces of the rotary drum, and the magnetic tape during running does not damage the rotary drum and the fixed drum. Since a better contact state can be obtained as compared with the conventional rotary head device, the tape tension on the tape entry side can be set lower than that of the conventional rotary head device. As a result, it is possible to reduce the power consumption of the capstan motor for running the magnetic tape.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, noise due to discharge of static electricity generated in the charged body is also shielded by the conductor, and this noise is not generated in the magnetic head. .

[Brief description of drawings]

FIG. 1 is a partial front view showing the configuration of a rotary head device according to an embodiment of the present invention.

FIG. 2 is a partial bottom view showing the configuration of the rotary head device of this embodiment.

FIG. 3 is a perspective view showing a configuration example of a conventional rotary head device.

FIG. 4 is a front view showing the vicinity of a magnetic head in a conventional rotary head device.

FIG. 5 is a bottom perspective view of a rotary drum in a conventional rotary head device.

FIG. 6 is a schematic diagram showing a floating state of a magnetic tape in the vicinity of a cutout portion in a conventional rotary head device.

[Explanation of symbols]

 2 Rotating Drum 3 Fixed Drum 4 Slit 5 Magnetic Tape 6 Magnetic Head 7 Sliding Part 8 Notch 9 Magnetic Gap 11 Rotary Head Device 12 Charger 13 Conductor

Claims (2)

[Claims] 1. A rotary head device comprising: a fixed drum; and a rotary drum that is rotatably held coaxially with the fixed drum and has a magnetic head provided in a cutout portion. A rotary head device, wherein a charging member is provided on at least one of a rotation direction and a rotation axis direction. 2. The rotary head device according to claim 1, further comprising a conductor provided between the magnetic head and the charged body.