JPH10255354A - Rotary head drum device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the vibration of a magnetic tape and the spacing between a rotary head drum and a magnetic tape from being increased due to an airflow and to stably record and reproduce data by disposing an airflow collision member at an entrance of the rotary head drum for the magnetic tape. SOLUTION: The airflow collision member 21 is disposed at about the same height as an upper rotary drum 8-1 of the rotary head drum with a gap G set to <=2mm against the outer circumferential surface of the rotary drum 8-1 in a triangular space between a tape entrance guide 7-1 and a contact starting point P-1 of the rotary drum 8-1 with the magnetic tape 3 in the case of rotation of the rotary drum 8-1 in the direction of (b). The airflow A generated by high speed rotation of the rotary drum 8-1 is made to collide with the airflow collision member 21 and is damped so that flapping the magnetic tape 3 is suppressed to prevent deterioration of an S/N and occurrence of an error due to vibration of the magnetic tape 3, and also increasing of spacing between the rotary drum 8-1 and the magnetic tape 3 by the airflow is eliminated to prevent a reproducing output from deteriorating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a rotary head drum device applied to a magnetic recording / reproducing apparatus for recording and reproducing data on a magnetic tape by a helical scan system such as a video tape recorder and a data recorder. It is.

[0002]

2. Description of the Related Art Conventionally, in a magnetic recording / reproducing apparatus such as a video tape recorder or a data recorder, data is recorded and reproduced by a rotating head drum while a magnetic tape is wound around the rotating head drum in a helical manner and travels. ing. FIG. 10 shows a tape running system of a conventional magnetic recording / reproducing apparatus of this kind, in which a supply reel 2-1 in a tape cassette 1 and a fed magnetic tape 3 are guide posts 4-1. Side tension regulator 5-1, full width erase head 6, tape entrance guide 7-1
And enters the drum entrance 9-1 which is the entrance of the rotary head drum 8 to the magnetic tape 3. And the drum entrance 9
The magnetic tape 3 is helically wound around the outer circumference of the rotary head drum 8 between -1 and the drum outlet 9-2. The magnetic tape 3 that has exited to the drum entrance 9-2 is drawn out to the preceding guide roller 13 via the tape exit guide 7-2, the CTL / TC head 10, the guide post 4-2, the capstan 11, and the pinch roller 12, and The guide posts 4-3, 4-4, and the winding-side tension regulator 5-
2. The take-up reel 2-2 in the tape cassette 1 via the guide post 4-5, the inclined guide 14, and the guide post 4-6.
It is wound up. At the time of recording and reproduction, the magnetic tape 3 is pressed against the capstan 11 by the pinch roller 12, and the magnetic tape 3 is unwound from the supply reel 2-1 and wound in the direction of arrow a so as to be wound on the take-up reel 2-2. While traveling at a constant speed, data is recorded on the magnetic tape 3 by the helical scan method using the rotating head drum 8,
It is configured to be played. In this embodiment, the rotary head drum 8 is rotated at a high speed in the direction of arrow b which is a counterclockwise direction. Note that in FIG.
Reference numerals 16-1 and 16-1 denote loading rings for loading / unloading the magnetic tape 3 by circularly moving the leading guide roller 13, the pinch roller 12, the guide posts 4-3, 4-4, and 4-5. -2, 16-
Reference numeral 3 denotes a tension arm, and reference numeral 17 denotes a mechanical chassis to which the entire tape running system is attached.

[0003] Fig. 11 shows the flow of air around the outer circumference of the rotary head drum 8. When the rotary head drum 8 is rotated at a high speed, the outer circumferential surface of the rotary head drum 8 is originally formed. Due to the viscosity of the air, a rotating air flow A is generated so as to be pulled in the same direction as the rotating direction of the rotating head drum 8, and the air flow A causes a submicron gap between the magnetic tape 3 and the rotating head of the rotating head drum 8. An air layer of the order is formed, and the rotary head records and reproduces data in a non-contact state with the magnetic tape 3.

[0004]

At this time, the rotating head drum 8 includes a medium rotating drum system (a rotating disk provided with a rotating head between a pair of upper and lower fixed drums) and an upper rotating drum. (A rotary head drum 8 of the upper rotary drum type), which is composed of an upper rotary drum provided with a rotary head and a lower fixed drum disposed below the upper rotary drum. Has a large outer peripheral surface area, a large amount of the air flow A described above is generated. The air flow A violently beats the magnetic tape 3 at the drum entrance 9-1, and the magnetic tape 3 vibrates finely. The vibration is transmitted to the magnetic tape 3 on the outer periphery of the rotary head drum 8, and the hit waveform is vibrated. In some cases. This fine vibration of the magnetism is remarkably generated from the entrance TI of the rotary head to the center TO of the rotary head against the magnetic tape 3 on the outer periphery of the rotary head drum 8, and if this vibration is large,
In the case of an analog device, the S / N ratio is reduced, and in the case of a digital device, an error rate is deteriorated. Further, when the air flow A is large, a large amount of air enters between the rotary head drum 8 and the magnetic tape 3 at the hit inlet TI, and the rotary head drum 8 In some cases, the spacing between the magnetic tape 3 and the magnetic tape 3 increases, and the hitting waveform may drop, leading to deterioration of the reproduction output, and again, lowering of the S / N ratio and deterioration of the error rate. I have.

FIG. 12 shows the envelope of the reproduced signal, and the horizontal axis is the time axis. Then, FIG. 12A shows a state in which the center T is reached from the entrance T-I.
This shows a normal state in which the envelope of the reproduction signal is flat toward -C. On the other hand, FIG. 12B shows that the magnetic tape 3 is finely vibrated by the air flow A, and the
12C shows an abnormal state in which the hit waveform oscillates, and FIG. 12C shows an abnormal state in which the hitting waveform drops at the hit inlet TI as a result of the increased spacing by the air flow A. It is. When the rotation direction of the rotary head drum 8 is clockwise (the opposite direction of the arrow b), the entrance of the rotary head drum 8 to the magnetic tape 3 moves to the hitting outlet TO, and the hitting outlet TO portion In this case, the above-described vibration and drop of the hit waveform occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an air flow generated on the outer peripheral surface of a rotary head drum by high-speed rotation of the rotary head drum vibrates by hitting a magnetic tape. It is an object of the present invention to provide a rotary head drum device capable of preventing an increase in spacing between the magnetic head and the magnetic tape.

[0007]

According to the present invention, there is provided a rotary head drum device according to the present invention, wherein an air flow collision member is disposed at an entrance of the rotary head drum to a magnetic tape.

In the rotary head drum device of the present invention configured as described above, since the airflow impingement member is arranged at the entrance of the rotary head drum to the magnetic tape, it is generated on the outer peripheral surface by the high speed rotation of the rotary head drum. The airflow can be attenuated by colliding with the airflow collision member, and the airflow hits and oscillates the magnetic tape or increases the spacing between the rotating head drum and the magnetic tape. Can be prevented beforehand.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rotary head drum device to which the present invention is applied will be described below with reference to FIGS. Note that the same components as those in FIGS. 10 to 12 are denoted by the same reference numerals, and redundant description will be omitted.

[Structure of Rotating Head Drum] First, in the present embodiment, as shown in FIGS. 4, 7, and 9, the rotating head drum 8 includes an upper rotating drum 8-1 and a lower fixed drum 8-2. And the upper rotating drum system constituted by the above. The upper rotating drum 8-1 is indicated by an arrow b in FIG.
Direction at high speed.

FIG. 1 and FIG. 2 show the outline of the rotary head drum device of the present invention. At the drum entrance 9-1 which is the entrance of the rotary head drum 8 to the magnetic tape 3 when 1 is rotated in the direction of the arrow b, the tape entrance guide 7-1 and the contact of the upper rotary drum 8-1 with the magnetic tape start. Point P-1
The air flow impingement member 21 is arranged at substantially the same height as the upper rotary drum 8-1 in a substantially triangular space between the air flow impingement member 21 and the outer circumference of the upper rotary drum 8-1. The gap G between the surface and the surface is 2 mm or less, preferably 0.5 mm
０．８0.8 mm. At this time, the number and shape of the air flow collision members 21 can be freely selected. When the upper rotary drum 8-1 is rotated in the direction opposite to the direction of the arrow b, the airflow collision member 21 is moved to the tape outlet guide 7-2 at the drum outlet 9-2.
And the contact end point P-2 of the upper rotary drum 8-1 with the magnetic tape 3 is disposed symmetrically in a substantially triangular space.

When the airflow impingement member 21 is arranged at substantially the same height as the upper rotary drum 8-1 at the drum inlet 9-1, the upper rotary drum 8-1 moves at a high speed in the direction of arrow b. The air flow A generated on the outer peripheral surface of the rotary drum 8-1 due to the rotation collides with the air flow collision member 21 at the drum inlet 9-1 and is attenuated. It is possible to prevent the magnetic tape 3 from being violently hit in one portion. As a result, the inlet T-I is hit by the airflow A.
As shown in FIG. 12B, the magnetic tape 3 is finely vibrated at the portion, and the hitting waveform is vibrated, thereby preventing the S / N ratio from being lowered and the error rate from being deteriorated. Also, a large amount of airflow A enters between the upper rotary drum 8-1 and the magnetic tape 3 at the hit inlet TI, and the upper rotary drum 8-1 at the hit inlet TI.
In this case, the spacing between the magnetic tape 3 and the magnetic tape 3 is increased, causing a drop in the hit waveform as shown in FIG. 12C, causing a decrease in the reproduction output and an increase in the error rate. Can be prevented. That is, by adopting the present invention, as shown in FIG. 12A, the envelope of the reproduced signal is always flat from the hit entrance TI to the hit center TC, and is highly accurate, stable, and high in transfer. It is now possible to record and reproduce rate data.

[First Embodiment of Air Flow Collision Member] Next, FIGS. 3 to 5 show a first embodiment of the air flow collision member 21, wherein a cylindrical member having a cylindrical hole 22 is shown. 2
3, a split groove 24 is formed over the entire width in the axial direction,
A pair of fastening pieces 25, 2 opposed to both sides of the split groove 24;
6 is formed integrally with the cylindrical member 23, and the pair of fastening pieces 2
A lock screw 27 for tightening them so that they are attracted to each other is attached between the upper and lower ends of the first and second tightening pieces 25. One end 29-1 of the air flow collision thin plate 29 is fixed to the side surface of the collision projection 28 by two setscrews 30. The cylindrical member 23 integrally formed with the fastening pieces 25 and 26 and the airflow collision projection 28 and the air collision thin plate 29 screwed to the cylindrical member 23 are formed of a light metal such as aluminum or a synthetic resin. I have. In addition, the air flow collision thin plate 29 may be integrally formed with the air flow collision projection 28.

The air flow collision member 21 thus configured
Is a tape entrance guide 7-1 as shown in FIGS.
It can be easily and accurately attached to the outer periphery of the base 41-1 of the tape exit guide 7-2. That is, the tape entrance guide 7-1 and the tape exit guide 7-2 are attached to the outer periphery of the upper end of the guide column 41, and the base 41-1 which is the lower end of the guide column 41 is stopped at the upper portion of the mechanical chassis 17. It is fixed with high precision and firmly by screws 42. The outer diameter of the base 41-1 is determined by the tape entrance guide 7-1 and the tape exit guide 7-2.
It is configured to be slightly larger than the outer diameter of. Therefore, the cylindrical member 23 of the air flow collision member 21 is inserted into the outer periphery of the base 41-1 from above the tape entrance guide 7-1 and the tape exit guide 7-2 by the cylindrical hole 22, and the lock screw 27 is inserted into a tool such as a hexagon wrench. By tightening while pressing from the direction of arrow c, the tightening pieces 25 and 26 are tightened to draw each other by utilizing the gap of the split groove 24.
Then, the cylindrical member 23 is fastened to the outer periphery of the base 41-1 and the airflow collision member 21 is easily fixed to the outer periphery of the base 41-1. At this time, the lock nut 27 is pressed by the tool in the direction of arrow c. Thereby, the cylindrical member 23
Of the lower fixed drum 8-2 which is a fixed portion of the rotary head drum 8 (however, the tape lead 8
(Position lower than −3) in the direction of arrow c, and the airflow impingement member 21 is positioned and fixed with high precision and high accuracy with respect to the upper rotary drum 8-1.

In the first embodiment, since the air flow collision thin plate 29 is screwed to the side surface of the air flow collision projection piece 28 of the air flow collision member 21, the air flow collision thin plate 29 is screwed. Can be brought as close as possible to the contact start point P-1.
Between the tip 29-2 of the upper rotary drum 8-1 and the outer circumference of the upper rotary drum 8-1 (actually, the outer circumference of a plurality of rotary heads slightly protruding from the outer circumference of the upper rotary drum). The minimum value can be set to 0.5 mm. If the gap G-1 is set to 0.5 mm, the above-described air flow A can be almost completely collided and attenuated, and the outer circumference of the upper rotary drum 8-1 and the magnetic tape 3 can be attenuated. 12 can be almost completely prevented, and both the vibration and the drop of the hit waveform shown in FIGS. 12B and 12C can be surely prevented.

"Second Embodiment of Air Flow Collision Member" Next, FIGS. 6 and 7 show a second embodiment of the air flow collision member 21. The collision thin plate 29 is removed so that the airflow A can be collided and attenuated only by the airflow collision projection 28, and the tape entrance guide 7-1 and the tape exit guide 7-2 can be used. The method of attaching the base portion 41-1 to the outer periphery is as follows.
This is the same as the embodiment.

According to the second embodiment, since the airflow collision projecting piece 28 cannot be brought very close to the contact start point P-1, the airflow collision projection piece 2 cannot be brought close to the contact start point P-1.
The gap G-2 between the outer circumferential surface of the upper rotating drum 8 and the outer periphery of the upper rotating drum 8-1 is about 0.7 to 0.8 mm.
9, and the cost can be reduced by reducing the number of parts and the number of assembly steps by omitting the set screw 29. Further, even if the gap G-2 is about 0.7 to 0.8 mm, the gap G-2 exerts a sufficient effect on the collision and attenuation of the airflow A, and in particular, is shown in FIG. Vibration of the hit waveform can be reliably prevented.

"Third Embodiment of Air Flow Collision Member" Next, FIGS. 8 and 9 show a third embodiment of the air flow collision member 21. In this case, a cylindrical member 23 is used. Groove 24, a pair of tightening pieces 25, 26 and a lock screw 27
Is removed, and a base 31 is integrally formed at the bottom of the cylindrical member 23. Then, the cylindrical member 23 is inserted into the outer periphery of the base 41-1 of the tape entrance guide 71-1 and the tape exit guide 7-2 from above, and the base 31 at the bottom is inserted into the full width erasing head 6 and the CTL / TC head 10-1.
Is mounted on a fixed head base 43 which is a base of the fixed head. Then, the fixed head base 43 is attached to the chassis 1
When the fixed head base 43 is fitted to the dowel 44 formed on the base 7 by the dowel hole 45 and the fixed head base 43 is fastened and fixed to the chassis 17 by the fastening screw 46, the fastening screw 46 is attached to the base of the cylindrical member 23. Arc hole 3 formed in 31
2 and screwed into the chassis 17, and the tightening screw 46 allows the base 31 and the fixed head base 4 to be screwed.
3 are fastened together (the fixed head base 43 is sandwiched between the base 31 and the chassis 17 and fastened).

Also in this case, the cylindrical member 23 or the base 31 in the direction indicated by the arrow c is pressed together with the outer periphery of the lower fixed drum 8-2 from the direction indicated by the arrow c, and tightened together by the tightening screw 46. Thereby, the airflow collision member 21 can be positioned with high accuracy with respect to the outer periphery of the upper rotary drum 8-1. 8 and 9 show a state in which the airflow collision thin plate 29 is omitted and the gap between the airflow collision projection 28 and the outer periphery of the upper rotating drum 8-1 is set to G-2. As shown in the drawing, similarly to the first embodiment, the air flow collision thin plate 29 is attached to the side surface of the air flow collision projection piece 28, and the tip 29-2 of the air flow collision thin plate 29 and the upper rotating drum. The gap between the outer circumference of 8-1 and G-1 can be set to G-1. According to the third embodiment, the airflow collision member 21 and the fixing head can be simultaneously fixed in one tightening step, and the number of parts and the number of assembly steps can be reduced.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be effectively modified based on the technical idea of the present invention. For example, in the above-described embodiment, the rotary head drum of the upper rotary drum type has been described, but the present invention is also applicable to a rotary head drum of the middle rotary drum type. In addition, the air flow collision member 21 is connected to the lower fixed drum 8-
It is also possible to attach to a fixed part such as 2.

[0021]

The rotary head drum device of the present invention configured as described above has the following effects.

According to a first aspect of the present invention, an air flow collision member is disposed at an entrance of the rotary head drum with respect to the magnetic tape, and an air flow generated on the outer peripheral surface by the high speed rotation of the rotary head drum is caused to collide with the air flow collision member. To prevent the airflow from hitting and vibrating the magnetic tape or increasing the spacing between the rotating head drum and the magnetic tape. In addition, it is possible to prevent the fluctuation (vibration) of the hitting waveform and the reduction of the reproduction output, and to record and reproduce the data with high accuracy and stability.

According to a second aspect of the present invention, in the rotary head drum device of the upper rotary drum type, since the airflow impingement member is provided at a position near the upper rotary drum at the entrance of the upper rotary drum to the magnetic tape, the upper rotary drum is provided. A large amount of air flow generated on the outer peripheral surface by the high-speed rotation of the drum is caused to collide with the air flow collision member, and can be reliably attenuated. Increase in the spacing between the magnetic tape and the magnetic tape can be prevented beforehand, and the fluctuation (vibration) of the hitting waveform and the decrease in the reproduction output can be prevented beforehand, so that high accuracy and stability can be achieved. In addition, data can be recorded and reproduced at a high transfer rate.

According to a third aspect of the present invention, since the air flow collision member is disposed between the tape entrance guide or the tape exit guide and the contact start point of the rotary head drum with respect to the magnetic tape, the air flow generated by the rotation of the rotary head drum is reduced. Collision and attenuation can be ensured.

According to a fourth aspect of the present invention, since the air flow collision member is formed of a thin plate, the gap between the air flow collision member and the outer periphery of the rotary head drum can be reduced to about 0.5 mm. Collision and damping, and intrusion of air between the rotary head drum and the magnetic tape can be prevented very effectively.

According to a fifth aspect of the present invention, the airflow collision member is inserted into the outer periphery of the base of the tape entrance guide or the tape exit guide and is fixed by pressing against the fixing member of the rotary head drum.
The gap between the airflow collision member and the rotary head drum can be set easily and with high accuracy.

According to a sixth aspect of the present invention, the airflow collision member is inserted into the outer periphery of the base of the tape entrance guide or the tape exit guide, pressed against the fixed portion of the rotary head drum, and fixed together with the fixed fixed head base. Therefore, the gap between the airflow collision member and the rotary head drum can be set easily and with high accuracy, and the number of parts and the number of assembling steps can be reduced by the co-fastening method, thereby achieving cost reduction.

According to the eighth aspect, the gap between the air flow collision member and the rotary head drum is set to 2 mm or less, so that the air flow generated by the rotation of the rotary head drum can be reliably collided and attenuated.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating an outline of a rotary head drum device to which the present invention is applied.

FIG. 2 is a plan view showing a tape running system of a helical scan type magnetic recording / reproducing apparatus incorporating a rotary head drum device to which the present invention is applied.

FIG. 3 is a plan view illustrating a first embodiment of an airflow collision member in the rotary head drum device of the present invention.

FIG. 4 is a partially cutaway side view of FIG. 3;

FIG. 5 is a perspective view of the airflow collision member according to the first embodiment.

FIG. 6 is a plan view illustrating a second embodiment of an airflow collision member in the rotary head drum device of the present invention.

FIG. 7 is a partially cutaway side view of FIG. 6;

FIG. 8 is a plan view illustrating a third embodiment of an airflow collision member in the rotary head drum device of the present invention.

FIG. 9 is a partially cutaway side view of FIG. 8;

FIG. 10 is a plan view illustrating a tape running system of a conventional helical scan type magnetic recording / reproducing apparatus.

FIG. 11 is a plan view illustrating vibration and spacing of a magnetic tape caused by airflow in a conventional rotary head drum device.

FIG. 12 is a view for explaining vibration and drop of a hit waveform in an envelope of a reproduction signal.

[Explanation of symbols]

3 is a magnetic tape, 6 is a full width erasing head which is a fixed head, 7-1 is a tape entrance guide, 7-2 is a tape exit guide, 8 is a rotary head drum, 8-1 is an upper rotary drum,
8-2 is a lower fixed drum, 9-1 is a drum inlet, 9-2 is a drum outlet, 21 is an air flow collision member, 23 is a cylindrical member,
24 is a split groove, 25 and 26 are fastening pieces, 27 is a lock screw,
28 is an airflow collision projection, 29 is an airflow collision thin plate,
1 is a base, 32 is an arc hole, 41 is a guide support, 41-
1 is the base of the guide column, 43 is the fixed head base, 46
Is a fastening screw for co-fastening, and A is an air flow.

Continued on the front page (72) Inventor Kenji Kobayashi Inside Sony Corporation 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo

Claims (7)

[Claims] 1. A rotary head drum device comprising: a rotary head drum; and a magnetic tape running helically wound around the outer circumference of the rotary head drum, wherein air is supplied to an entrance of the rotary head drum with respect to the magnetic tape. A rotary head drum device comprising a flow collision member. 2. A rotary head drum device comprising: a rotary head drum constituted by an upper rotary drum and a lower fixed drum; and a magnetic tape wound helically around the outer circumference of the rotary head drum and running. A rotary head drum device, wherein an air flow impingement member is disposed at a position near an outer periphery of the upper rotary drum at an entrance of the upper rotary drum to the magnetic tape. 3. The air flow collision member is disposed between a tape entrance guide or a tape exit guide and a starting point of contact of the rotary head drum with the magnetic tape. The rotary head drum device as described in the above. 4. The rotary head drum device according to claim 1, wherein said air flow collision member is formed of a thin plate. 5. The rotating device according to claim 3, wherein said air flow colliding member is inserted into the outer periphery of a base of said tape entrance guide or tape exit guide, and is fixed by pressing against a fixing member of said rotary head drum. Head drum device. 6. The method according to claim 6, wherein the air flow collision member is inserted into the outer periphery of the base of the tape entrance guide or the tape exit guide, pressed against the fixed portion of the rotary head drum, and fastened together with the fixed head base. The rotary head drum device according to claim 3, wherein: 7. The rotary head drum device according to claim 1, wherein a gap between the air flow collision member and the rotary head drum is set to 2 mm or less.