JP2002170303A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording and reproducing device in which a magnetic head can be made to smoothly advance to a magnetic tape. SOLUTION: A head drum unit consists of a bottom drum 1 having a helical guide 4, a middle rotating drum 2 provided with the magnetic head 6 and mounted on the bottom drum 1 in a rotatable way and a top drum 2 mounted almost coaxially to the bottom drum 1. The head drum unit is provided with an entrance guide post 19 for guiding a magnetic tape 5 at the entrance of the head drum unit, and the magnetic tape 5 to be wound around the head drum unit. The head drum unit has a protecting means 10 constituted so that the winding start position of the magnetic tape 5 is a position where the magnetic head 6 advances from the end face of the magnetic tape 5, also the magnetic head 6 is brought into contact with the magnetic tape 5 from a position that is ahead of the winding start position of the magnetic tape 5 and the magnetic tape 6 starts to be in contact with the inside face of the magnetic tape 5 at the advance point the magnetic tape 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium rotating drum type and pre-read type magnetic recording / reproducing apparatus for recording a helical track on a magnetic tape.

[0002]

2. Description of the Related Art In recent years, with digitalization of magnetic recording progressing, a compression system has become mainstream. When performing pre-reading, a problem with the compression method is that it takes more time to compress or expand. Therefore, in order to attach the pre-read head ahead of the recording / reproducing head, a large amount of advance is required, and in order to ensure that the pre-read head hits the magnetic tape at the drum entrance, it is necessary to wrap the drum entrance around the The angle must be increased.

FIG. 9 is a schematic perspective view of a conventional head drum device. Coaxial with the lower drum 1 having the helical guide 4, the rotating middle rotating drum 3 having the magnetic head 6
And the fixed upper drum 2 are arranged with gaps 7 and 8, respectively. The magnetic tape 5 has a helical guide 4
From the winding start line 22 to the drums 1 to 3
Wrapped around. The winding start line 22 is set so that the magnetic head 6 starts to hit from within the plane of the magnetic tape 5.

FIG. 10 is a partial view of the head drum device shown in FIG. Since the magnetic head 6 is located at a position where the magnetic tape 5 starts to enter and in a plane within a tangent line,
The tent 23 starts to be formed and hit in the plane of the magnetic tape 5.

FIG. 11 is a schematic diagram showing the relationship between the magnetic tape pattern and the magnetic head 6. As shown in FIG. On the magnetic tape 5,
A helical track group 25 is recorded. In the case of the compression type magnetic tape format, the signal processing takes a long time. Therefore, in order to process the helical track 26, it is necessary to read the data at the position of the preceding helical track 27. Therefore, the pre-read head 21 is arranged at the position of the preceding helical track 27 with respect to the magnetic head 6.

Normally, in the vicinity of the start of the drum device winding, an overlap OW is required to secure the contact with the magnetic head 6.
1 is set. In the overlap OW1, the helical track 26 and the winding start line 22 intersect in the plane of the magnetic tape 5 so that the magnetic head 6 does not enter from the lower end surface of the magnetic tape 5.

However, in such a state, FIG.
When the helical track 27 as shown in FIG.
Cannot be read because the pre-read head 21 does not hit the magnetic tape 5. For this purpose, the overlap OW2 needs to be further added to extend to the winding start line 22.

FIG. 12 is a schematic perspective view showing a state where the winding start line 22A is extended. Since the winding start position is extended to the winding start line 22A, the magnetic head 6
Is in a state of starting contact with the magnetic tape 5 from the lower end face.

FIG. 13 shows a state diagram when the magnetic head 6 enters the magnetic tape 5 from the lower end face. The magnetic head 6 comes into contact with the lower end surface of the magnetic tape 5 at a shallow angle from the lower end surface of the magnetic tape 5. Therefore, the end face of the magnetic head 6 pushes up the lower end face of the magnetic tape 5, and wrinkles 29 are generated on the magnetic tape 5.
That is, there is a problem that the magnetic tape may be damaged and sometimes the magnetic tape 5 may be cut.

[0010]

In the conventional head drum device described above, when the delay time until the pre-read position is long, the magnetic head 6 enters the magnetic tape 5 from the lower end surface of the magnetic tape 5 and the magnetic head 6 There is a problem that the lower end of the tape 5 is damaged.

An object of the present invention is to provide a magnetic recording / reproducing apparatus which solves this problem and enables a magnetic head to smoothly enter a magnetic tape.

[0012]

According to another aspect of the present invention, there is provided a magnetic recording / reproducing apparatus comprising: a lower drum having at least a helical guide;
A head drum device is constituted by a middle rotating drum rotatably mounted on the lower drum and having a magnetic head, and an upper drum substantially coaxially mounted on the lower drum. And a magnetic tape wound around the head drum device.The winding start position of the magnetic tape is set to a position where the magnetic head enters from the end face of the magnetic tape, and the magnetic head is Having a protection means configured to contact the magnetic tape from a position before the winding start position of the magnetic tape and to start contacting the magnetic head in the plane of the magnetic tape at the entry point of the magnetic tape. It is.

Therefore, according to the first aspect of the present invention, when the magnetic head enters from the end face of the magnetic tape, the magnetic tape comes into contact from within the plane of the magnetic tape because the magnetic tape is lifted by the protection means. Damage can be avoided and stable running can be achieved by guiding the lower end surface of the magnetic tape by the protection means, and high reliability can be achieved.

According to a second aspect of the present invention, there is provided the magnetic recording / reproducing apparatus according to the first aspect, wherein the upper drum has a guide means for guiding an upper end surface of the magnetic tape. It is.

According to the second aspect of the present invention, the upper end surface of the magnetic tape is guided by the guide means, so that the magnetic tape is prevented from moving in the direction away from the helical guide, and the linearity of the track and the running of the magnetic tape can be reduced. The stability can be maintained, so that the stable running by the guide of the lower end surface of the magnetic tape by the protection means is added to the stable running by the guide of the upper end surface of the magnetic tape, so that higher reliability can be achieved.

According to a third aspect of the present invention, there is provided the magnetic recording / reproducing apparatus according to the first or second aspect, wherein the protection means includes a projection at a lower end side contact position of the magnetic tape. On the inner magnetic tape side,
It is characterized in that a guide portion lower than the projection is provided.

According to the third aspect of the present invention, the lower end of the magnetic tape is lifted by the guide portion on the drum side with respect to the contact start line, thereby preventing the magnetic tape from dropping into the protection means and the head drum device. In addition, the contact between the magnetic head and the magnetic tape can always be started in the plane of the magnetic tape.

According to a fourth aspect of the present invention, in the magnetic recording / reproducing apparatus according to the first aspect of the present invention, the protection means includes a protrusion at a position where the lower end of the magnetic tape contacts the magnetic tape. In addition, a guide for guiding the lower end surface of the magnetic tape is provided substantially on an extension of the helical guide.

Therefore, according to the fourth aspect of the present invention, the helical guide formed on the lower drum cannot be increased in accordance with the increase even if the winding angle of the drum entrance is increased. The guide for holding the magnetic tape along the extension has the effect of ensuring the regulation of the magnetic tape near the drum entrance.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a positional relationship between a head drum device and a magnetic tape according to an embodiment of the present invention. In FIG. 1, the magnetic tape 5 is separated from the contact start line 18 by the upper drum 2, the middle rotating drum 3 having the magnetic head 6, and the helical guide 4.
Is wound around the lower drum 1. The upper drum 2 is provided with an upper guide 18 as an example of guide means for regulating the upper end of the magnetic tape 5, and the lower drum 1 is provided with a protection device 10 as an example of protection means via a mounting hole 11 or the like. Attached. The gap 7 and the gap 8 correspond to the upper drum 2,
It is provided between the middle rotating drum 3 and the lower drum 1.

FIG. 2 is an enlarged view of the vicinity of the distal end of the protective device 10. As shown in FIG. The protector 10 has a projection 12 at the lower end side contact position of the magnetic tape 5, and a guide 13 lower than the projection 12 on the side of the magnetic tape 5 inside the projection 12. Further, the magnetic tape 5 is provided on the protrusion 12 substantially on the extension of the helical guide 4.
A guide 14 is provided for guiding the lower end of the guide. The guide 13 has a convex surface 13 a for lifting the magnetic tape 5 in the radial direction of the drum, and the protrusion 12 has a flank 12 a continuous from the guide 14.

FIG. 3 shows a side view. Guided by the entrance guide post 19, the magnetic tape 5 is wound around the head drum device, and the guide 14 and the upper guide 1 are wound.
After being guided by 8, it is guided by the helical guide 4.
The lower part of the convex surface 13a forms a convex surface straddling the contact start line 20, and is configured to contact the magnetic tape 5 from outside the contact start line 20. The flank 12a is provided to prevent the magnetic tape 5 from being guided in an unnecessarily long range.

FIG. 4 is a top view. The lower end of the magnetic tape 5 is formed by the lower end of the convex surface 13a of the protective device 10.
Can be lifted slightly. The surface of the lifted magnetic tape 5 gradually releases its distortion toward the entrance guide post 19. The contact between the magnetic tape 5 and the upper end of the protective device 10
When the shape of the convex surface 13a is the upper guide 2 side and the entrance guide post 19
The projection 12 has a surface that escapes to the side.
The upper portion enters a space defined by a tangent line between the entrance guide post 19 of the magnetic tape 5 and the head drum device and the head drum device, and does not contact the magnetic tape 5.

A minute gap is formed between the protector 10 and the middle rotating drum 3 (not shown in FIG. 4) to prevent the rotating middle rotating drum 3 from contacting the protector 10. The guide portion is a taper 15, and this taper 15 is provided to prevent the air of the middle rotating drum 3 from being rapidly compressed.

FIG. 5 is a sectional view. The protection device 10 is lifted by the convex surface 13a, and
A groove 16 is provided in the protector 10 in order to avoid a collision between the magnetic head 6 protruding from the head and the protector 10.

6 to 8 show details of the protective device 10, FIG. 6 is a side view, FIG. 7 is a top view, and FIG. 8 is a sectional view. FIG.
5, the protector 10 includes a groove 16 for avoiding contact with the magnetic head 6, and a convex surface 13 that is more protruding downward for raising the lower end side of the magnetic tape 5.
a, the air layer of the middle rotating drum 3 has a taper 15 for avoiding a sudden collision with the protector 10 and a guide 14 for holding the magnetic tape 5 on an extension of the helical guide 4. Further, in order to avoid contact between the protector 10 and the middle rotating drum 3, a step 17 is provided above the groove 16 of the protector 10 from above.

Further, as described above, the convex 1
3a has a gentle taper upward, and contacts the lower end of the magnetic tape 5 on the drum side with respect to the contact start line 20 to lift the magnetic tape 5. As a result, the contact between the magnetic head 6 and the magnetic tape 5 starts in the plane of the magnetic tape 5.

The upper portion of the convex surface 13a is tapered so that it is sufficiently located in the space between the entrance guide post 19 and the tangent line between the head drum device and the head drum device and the magnetic tape 5 drawn by the head drum device. Convex surface 1
The upper end corner of 3a is not caught by the lower end of the magnetic tape 5, and also serves to prevent the magnetic tape 5 from dropping into the step 17.

At the position where it contacts the lower end of the convex surface 13a, the magnetic head 6 does not come into contact with the lower end of the magnetic tape 5, but the pre-read head is located at a position higher than the magnetic head 6. The contact is started at a position where the magnetic tape 5 comes into contact almost from the contact start point 20 without being affected by the convex surface 13a. The contact position advances before the normal magnetic head 6, and the entire length of the helical track shown in FIG. 11 can be reproduced.

The guide 14 shown in FIG. 2 cannot increase the helical guide 4 formed in the lower drum 1 in accordance with the increase even if the winding angle of the drum entrance is increased. This has the effect of ensuring the regulation of the magnetic tape 5 near the entrance.

The upper guide 18 guides the upper end surface of the magnetic tape 5, which restricts the magnetic tape 5 from moving in a direction away from the helical guide 4,
This is effective for maintaining track linearity and running stability.
The position of the upper guide 18 is provided between the lower end of the magnetic tape 5 and the vicinity of the guide 14 apart from the helical guide 4, and guides the upper end of the magnetic tape 5. The guidance of the magnetic tape 5 stabilizes the running of the magnetic tape 5 near the drum entrance.

In FIG. 1, the upper guide 18 as an example of the guide means is a pin fixed to the upper fixed drum 2, but it goes without saying that an adjustment method may be used. With the adjustment method, more accurate adjustment and management of track linearity can be performed. Also, the adjustable protector 10 is effective for more accurate adjustment and management of track linearity.

[0033]

As described above, according to the present invention, it is possible to prevent the magnetic head from coming into contact with the lower end of the magnetic tape near the entrance of the head drum device by using the protective device. A configuration in which the winding is made larger than usual can be obtained, and even in the compression type VTR format, the effect of performing pre-reading can be obtained by attaching the pre-read head by normal signal processing.

[Brief description of the drawings]

FIG. 1 is a perspective view of a head drum device according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a head drum unit at the winding start position.

FIG. 3 is a side view of the head drum device.

FIG. 4 is a top view of the head drum device.

FIG. 5 is a partial sectional view of the head drum device.

FIG. 6 is a side view of the protective equipment.

FIG. 7 is a top view of the protective equipment.

FIG. 8 is a sectional view of the protective equipment.

FIG. 9 is a perspective view of a conventional head drum device.

FIGS. 10A and 10B are general views of a head entering the magnetic tape, wherein FIG. 10A is a top view of a main part, and FIG.

FIG. 11 is an explanatory view of the position of the helical track and the pre-read.

FIG. 12 is a perspective view of the head drum device when the winding angle is enlarged.

13A and 13B are diagrams illustrating a magnetic head entering a magnetic tape when the winding angle is enlarged, wherein FIG. 13A is a top view of a main part, and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower drum 2 Upper drum 3 Middle rotation drum 4 Helical guide 5 Magnetic tape 6 Magnetic head 10 Protective equipment (protection means) 12 Projection part 12a Flank surface 13 Guide part 13a Convex surface 14 Guide 15 Taper 16 Groove 18 Upper guide (Guidance means) 19 Entrance guide post 20 Contact start point

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Akira Koga 1006 Kazuma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. (72) Inventor Kohei Shibata 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A head comprising: a lower drum having at least a helical guide; a middle rotating drum rotatably mounted on the lower drum; and an upper drum mounted substantially coaxially with the lower drum. A drum device is provided, and an entrance guide post for guiding the magnetic tape at the entrance of the head drum device, and a magnetic tape wound around the head drum device are provided, and the winding start position of the magnetic tape is The magnetic head is located at a position where it enters from the end face of the magnetic tape, and the magnetic head contacts the magnetic tape from a position before a winding start position of the magnetic tape, and at the entry point of the magnetic tape, the magnetic head contacts the magnetic tape. A magnetic recording / reproducing apparatus comprising a protection means configured to start contact of a head in a plane of a magnetic tape. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the upper drum has guide means for guiding an upper end surface of the magnetic tape. 3. The protection means according to claim 1, wherein the protection means comprises a projection at a lower end side contact position of the magnetic tape, and a guide section lower than the projection on the magnetic tape side inside the projection. A magnetic recording / reproducing device, comprising: 4. The guide according to claim 1, wherein the protection means includes a projection at a lower end side contact position of the magnetic tape and guides the lower end surface of the magnetic tape substantially on an extension of the helical guide. A magnetic recording / reproducing apparatus comprising: