JPS63144452A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the recording/reproducing accuracy by allowing a pad member depressed by a spring to depress a magnetic tape toward the circumferential face of a rotary drum so as to attain excellent contact state of the rotary head onto a magnetic tape. CONSTITUTION:With the rotary drum 2 driven at a high speed in the direction of arrow (a), air is going to flow between the circumferential face 2a of the rotary drum 2 and a magnetic tape 9 at an inlet part 17 from the direction of the arrow (a) by the air swallow-up function attended with the high speed drive of the rotary drum 2. Since the pad member 21 depressed toward the arrow (c) by a spring force of the spring 25 at the inlet part 17 depresses the magnetic tape 9 toward the circumferential face 2a, the quantity of the air flowing between the circumferential face 2a and the magnetic tape 9 is limited. As a result, the air film formed between the circumferential face 2a and the magnetic tape 9 is reduced. Thus, excellent contact of the rotary head 4 onto the magnetic tape 9 is obtained stably and the accuracy of recording/ reproduction is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a recording and reproducing device that is most suitable for application to, for example, a video tape recorder, a digital tape recorder, etc. It relates to something that can be wrapped around and run.

[Summary of the invention]

The present invention provides a recording/reproducing device in which a magnetic tape is wound around a circumferential surface of a rotary head drum and runs, using a spring force on the inlet side of the rotary head of the rotary head drum to move the magnetic tape onto the rotary drum. By providing a pad member that is pressed toward the circumferential surface, it is possible to improve the contact state of the rotary head with the magnetic tape.

[Conventional technology]

2. Description of the Related Art Conventionally, video tape recorders and the like have been constructed so that a magnetic tape is wound around a rotating head drum in a predetermined manner and is run. Then, the rotary head is rotated at high speed by the rotary drum in the opposite direction or in the same direction as the running direction of the magnetic tape, thereby performing desired recording and reproduction.

Conventionally, in this type of video tape recorder, an air film is formed between the circumferential surface of the rotating drum and the magnetic tape due to the air entrainment effect caused by the high-speed rotation of the rotating drum. The amount of air film is maximum at the entrance side of the rotary head to the magnetic tape, and minimum at the exit side of the rotary head to the magnetic tape. As a result, it is difficult to obtain good contact between the rotary head and the magnetic tape on the entrance side, resulting in a problem in that recording and reproducing accuracy cannot be improved.

Therefore, in order to solve this problem, conventional video tape recorders have developed two methods: ■ A method to increase the tension of the magnetic tape, ■ A method to release air into multiple annular grooves provided on the circumferential surface of the rotating drum, and ■ A method on the above-mentioned inlet side. The amount of air film on the inlet side has been reduced by, for example, pressing the magnetic tape directly against the circumferential surface of the rotating drum using a tape guide located at the inlet.

[Problem that the invention seeks to solve]

However, these conventional methods have the following problems.

In method (2), as a result of increasing the tension of the magnetic tape, the contact pressure between the magnetic tape and the rotating head increases, and not only does the magnetic tape and the rotating head tend to wear and damage each other, but the running of the magnetic tape itself tends to become unstable. That is, because magnetic tapes are becoming thinner due to higher density recording and longer recording times, the magnetic surfaces and edges of magnetic tapes are more likely to be damaged. If the edges are damaged, the running of the magnetic tape becomes unstable.

In method (2), the distribution of the air film is uniform on the circumferential surface of the rotating drum, and if an attempt is made to reduce the air film on the inlet side of the rotating head, the air film on the outlet side will be reduced too much.

With method ①, there is a risk that the splicing chive or leader tape may get caught between the rotating drum and the tape guide.
Furthermore, if the tape guide is worn out, it will no longer be effective. In particular, in a type of recording/playback device that uses cassettes, the tape guide must be configured to be movable in order to automatically wind the magnetic tape around the rotating head drum. Since the gap between the tape guide and the rotating drum was small, there was a risk that the tape guide would come into contact with the rotating drum. Furthermore, adjusting the small gap between the movable tape guide and the rotating drum requires a great deal of effort and skill.

The present invention utilizes spring force to press the magnetic tape toward the circumferential surface of the rotating drum, thereby reducing the air film formed between the circumferential surface of the rotating drum and the magnetic tape. It is intended to do so.

[Means for solving problems]

The present invention provides a recording/reproducing apparatus configured to run a magnetic tape wound around the peripheral surface of a rotary head drum in a predetermined state, in which a pad member is provided on the inlet side of the rotary head of the rotary head drum with respect to the magnetic tape. By pressing this pad member with a spring, the pad member presses the magnetic tape toward the circumferential surface of the rotating drum of the rotating head drum.

[Effect]

According to the present invention, the band member pressed by the spring presses the magnetic tape toward the circumferential surface of the rotating drum, so that air flowing between the circumferential surface of the rotating drum and the magnetic tape is prevented. The amount is limited to reduce the air film that forms between them.

〔Example〕

An embodiment in which the present invention is applied to a cassette video tape recorder will be described below with reference to the drawings.

First, as shown in FIGS. 2 and 3, the rotary head drum 1 includes a rotating drum 2 as an upper drum and a fixed drum 3 as a lower drum.

A plurality of rotating heads 4 made of magnetic heads are attached to the lower edge of the rotating drum 2, and these head chips 4a extend from the notches 5 provided in the rotating drum 2 to the circumferential surface 2a of the rotating drum 2. It is projected outward. The rotating drum 2 is connected to a motor 6 attached to the fixed drum 3.
In this embodiment, the rotary drum 2 is configured to be rotated at high speed in the direction of arrow a in FIG. 3.

On the other hand, the magnetic tape 9 is connected to a pair of sliders 10a and 10b.
Each pair of tape guides 11a, ll planted on
b, 12a and 12b, the tape is pulled out from a tape cassette (not shown), and is wrapped around the peripheral surface of the rotary head drum 1 at a predetermined angle, as shown by solid lines in FIG. In addition, at this time, as shown in FIG.
It is wound in a helical shape along the tape lead 13 provided at a.

In this embodiment, while the magnetic tape 9 is running at a constant speed in the direction of the arrow A, recording and reproduction are performed on the magnetic tape 9 by a plurality of rotary heads 4 of a rotary drum that is rotated at high speed in the direction of the arrow a.

By the way, in FIG. 3, the right tape guide lla
The part between and the rotary drum 2 is the entrance side part 17 of the rotary head 4 to the magnetic tape 9, and conversely, the part between the left tape guide Ilb and the rotary drum 2 is the part 17 of the rotary head 4 to the magnetic tape 9. Outlet side portion 18 of rotating head 4
It is.

Next, as shown in FIGS. 1 and 2, the inlet side portion 17
The details of the air film removing device 20 provided in the will be explained below.

First, the pad member 21 having a substantially prismatic shape is attached to the rotating drum 2.
The slider 10a is parallel to the peripheral surface 2ag of the slider 10a.
It is inserted into a groove 22 provided in the. A pin 23 horizontally attached to the back surface of the band member 21 is inserted into a hole 24 provided in the slider 10a, and the pad member 21 is disposed within the groove 22 in a perspective direction with respect to the circumferential surface 2a of the rotating drum 2. It is configured to be movable in the directions of arrows c and d. The pad member 21 is pressed in the direction of arrow C by a spring 25 which is a compression spring fitted around the outer periphery of the pin 23, and is rotated by an E ring 26 fitted around the outer periphery of the tip of the pin 23. The closest position of the pad member 21 to the circumferential surface 2a of the drum 2 is regulated. Note that the lower end of the pad member 21 is located slightly above the rotating head 4.

Next, the operation of this air film removing device 20 will be explained.

First, when the rotating drum 2 rotates at high speed in the direction of the arrow a, due to the air entrainment effect accompanying the high speed rotation of the rotating drum 2,
In the inlet side portion 17, the circumferential surface 2a of the rotating drum 2
Air tries to flow in between the magnetic tape 9 and the magnetic tape 9 from the direction of arrow a.

However, in this inlet side portion 17, the spring 2
Since the pad member 21 pressed in the direction of arrow C by the spring force 5 presses the magnetic tape 9 toward the circumferential surface 2a of the rotating drum 2, the contact between the circumferential surface 2a of the rotating drum 2 and the magnetic tape 9 increases. The amount of air that can flow in between is limited. As a result, the air film formed between the circumferential surface 2a and the magnetic tape 9 is reduced (the thickness of the air film is reduced).

Therefore, it is possible to stably obtain a good contact state of the rotary head 4 with the magnetic tape 9, and the accuracy of recording and reproduction can be significantly improved.

By the way, the pad member 21 pressed in the direction of arrow C by the spring 25 is stabilized at a position where the air film and the spring force of the spring 25 are balanced.
Gap G between the circumferential surface 2a of the rotating drum 2 and the magnetic tape 9
can be defined accurately without adjustment. When the splicing tape comes into contact with the pad member 21, the pad member 21 can escape in the direction of arrow d against the spring 25, so that the splicing tape can be moved by the rotating drive. The circumferential surface of the beam 2 and the rotating head 4 are not damaged.

Further, the pad member 21 is preferably wear-resistant, but since the pad member 21 is constantly pressed in the direction of arrow C by the spring 25, the gap G remains almost constant even if the band member 21 is slightly worn. It is maintained.

Note that no air film is formed between the circumferential surface 2a of the rotary drum 2 and the magnetic tape 9 when the rotation of the rotary drum 2 is started and stopped. Therefore, when the rotation of the rotary drum 2 is started and stopped, if the pad member 21 is attached to the magnetic tape 9
If the magnetic tape is pressed against the circumferential surface 2a of the rotating drum 2, there is a risk that the rotation of the rotating drum 2 may cause scratches on the circumferential surface 2a or the magnetic tape 9, or that the magnetic tape 9 may be cut. .

Therefore, in this cassette type video tape recorder, as shown in FIG. 3, when loading the magnetic tape 9, a pair of sliders 10a are moved in the direction of the arrow e.
, 10b has not yet reached the loading completion position shown by the solid line, for example, when it reaches the position shown by the chain line or earlier, the rotating drum 2 is made to rise to a predetermined rotational speed. Further, when unloading the magnetic tape 9, the pair of sliders 10a and 10b moved in the direction of the arrow f advance from the loading completion position shown by the solid line, for example, when they reach the position shown by the chain line, or at a later point. The rotating drum 2 is made to stop rotating at a late point in time.

Note that the position of the slider 10a indicated by the chain line is the position of the spring 25.
The movement of the pad member 21 in the direction of arrow C in FIG. This is a position where a gap of a certain size or more is formed.

Note that FIG. 4 shows a modified example, in which the lower end of the pad member 21 is extended to a position below the rotating head 4, and the pad member 21 is provided with a relief for the rotating head 4. A groove 28 is provided for this purpose. According to this modification, the contact of the rotary head 4 with the magnetic tape 9 can be further improved.

Although the present invention has been described above with reference to embodiments, the present invention is not limited to the embodiments, and various effective changes can be made based on the technical idea of the present invention.

Furthermore, the present invention is not limited to video tape recorders, but can be applied to various recording and reproducing apparatuses that include a rotating head drum, such as digital tape recorders.

〔Effect of the invention〕

As described above, the present invention uses a pad member pressed by a spring to press the magnetic tape toward the circumferential surface of the rotating drum, thereby causing air to flow between the circumferential surface of the rotating drum and the magnetic tape. The amount of air film formed between the magnetic tape and the circumferential surface of the rotating drum is reduced compared to conventional methods. can be reduced. Therefore, a good contact state of the rotary head with the magnetic tape can be obtained, and recording and reproducing accuracy can be improved.

However, by increasing the tension of the magnetic tape,
Since there is no need to increase the amount of protrusion of the rotary head from the circumferential surface of the rotary drum, the magnetic tape and the rotary head are not mutually worn and damaged, and the running of the magnetic tape can be stabilized. can. Moreover, compared to the method of providing a plurality of annular grooves on the circumferential surface of the rotating drum, the air film can be significantly reduced and made uniform. In addition, unlike the method of pressing the magnetic tape directly onto the circumferential surface of a rotating drum using a tape guide, there is no need to worry about the splicing tube or leader tape becoming wedged between the rotating drum and tape guide, or the loss of effectiveness due to tape guide wear. , both performance and reliability are high.

In particular, according to the present invention, since the pad member pressed by the spring is stabilized at a position where the air film and the spring are balanced, the gap between the circumferential surface of the rotating drum and the magnetic tape can be reduced. Not only can it be defined accurately without adjustment, but also the pad member can escape against the spring against the splicing tape or leader tape, so safety is extremely high.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a plan view of the main part, Fig. 2 is a sectional view of the main part, Fig. 3 is a plan view of the whole, and Fig. 4 is a modified example. FIG. In addition, in the symbols used in the drawings, 1...------...--- Rotating head drum 2
−・−・・−・・−・−・−・Rotating drum 2a −−
−−−−・−・−・−・Surrounding surface 4・−・−・−1−−−・−・−・Rotating head 9・−・
−・・−・−・・−Magnetic tape 17−・・−・・−・
---Inlet side portion 20---Air film removal device 21-------m----
-1-- Pad member 25-- Spring.

Claims (1)

[Scope of Claims] In a recording/reproducing device configured to run a magnetic tape wound around a circumferential surface of a rotary head drum in a predetermined state, the magnetic tape is provided on the inlet side of the rotary head of the rotary head drum with respect to the magnetic tape. 1. A recording/reproducing apparatus comprising: a pad member; and a spring which presses the pad member so that the pad member presses the magnetic tape toward the circumferential surface of the rotary drum of the rotary head drum.