JPH01296451A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To uniformize air pressure at an inlet part and an outlet part and hence to uniformize the reproducing of information by providing an air flow member of a prescribe shape at the outlet part where a magnetic tape is separated from an outer circumferential surface of a rotary head assembly. CONSTITUTION:The airflow control member 20 is provided in a space 21 of a triangular shape formed by the magnetic tape 1 between itself and the outer circumferential surface of the outlet part 14 of the rotary head assembly. This shape is established by a 1st side surface 20a formed along the outer circumferential surface with a constant space between them, a 2nd side surface 20b of a linear shape formed along the magnetic tape 1 with a certain space between them and a tip 20c facing toward the outlet part 14 as formed at an acute angle. Then, its width H is made as larger than the width of the magnetic tape 1 and fixed to a terminal substrate shield case 16 by a connecting member 22 so as to protrude upward and downward beyond the upper and lower edges of the tape. By this method, the air pressure at the inlet part and the outlet part is uniformized, and the reproducing of information can be uniformized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing device equipped with a rotary head assembly, such as a video tape recorder or a digital audio tape recorder, and particularly to an improvement in the recording/reproducing performance thereof.

[Prior Art] FIG. 5 is an axial sectional view of a rotary head assembly of a conventional video tape recorder. In the figure, (1) is a magnetic tape, (2) is a fixed cylinder, and the fixed cylinder ( 2) has a magnetic tape (1
) has a lead groove (202) that guides the travel of the lead groove (202). (3
) is the central axis fixed at the center of the fixed cylinder (2),
(4) is a rotating cylinder that is rotatably supported from the fixed cylinder (2) via a bearing (5), and (6) is a rotating cylinder that is supported by the rotating cylinder (4) and is connected to the fixed cylinder along the lead groove (202). (2) and a magnetic head that records information on a magnetic tape (1) running around a rotating cylinder (4) or reproduces information already recorded on the magnetic tape (1). (7) converts signals to be recorded or reproduced signals picked up from the magnetic tape (1) by the magnetic head (6) into a signal processing device (not shown) for processing these signals and the magnetic head (6). It is a rotary transformer that is transferred and received without contact between the rotary transformer and the fixed cylinder (2).
701), and a cylindrical rotary rotary transformer (701) fixed to the rotary cylinder (4) so as to face the fixed rotary transformer (701) at a distance from the outside in the radial direction.
702). (8) is a drive motor for rotationally driving the rotating cylinder (4), (801) is a stator fixed to the fixed cylinder (2), and (802) is a drive motor fixed to the rotating cylinder (4). It is a rotor.

Next, the operation will be explained. When the drive motor (8) is energized, the rotating cylinder (4) rotates around the central axis (3), and the magnetic head (6) transfers information to the magnetic tape (1) running along the lead groove (202). or reproduce information already recorded on the magnetic tape (1). During this time, the recording and playback signals are transferred to the rotary transformer (7).
The signal is transmitted between the magnetic head (6) and the signal processing device via the magnetic head (6).

Next, the behavior of the magnetic tape in a conventional rotary head assembly will be explained with reference to FIGS. 6 to 8. 6 is a schematic plan view showing the magnetic tape running path around the rotary head assembly of FIG. 5; FIG. 7 is a front view of FIG. 6;
FIG. 8 is a diagram showing deformation of the magnetic tape at various parts around the rotary head assembly of FIGS. 6 and 7;
FIG. 8(a) shows the deformation of the magnetic tape at the entrance where the magnetic tape begins to wrap around the rotating head assembly, and FIG. 8(b) shows the deformation of the magnetic tape at the exit where the magnetic tape leaves the rotating head assembly and at the entrance. FIG. 8(C) shows the deformation of the magnetic tape at the exit portion.

In FIGS. 6 and 7, (9) and (10) are magnetic tapes (1) extending around a fixed cylinder (2) and a rotating cylinder (4) at a predetermined angle (for example, 180°).
The rotating cylinder (4) rotates in the direction of the arrow (11), and the magnetic tape (1) runs in the direction of the arrow (12). After the magnetic tape (1) passes through the tape guide (9), it begins to wrap around the rotating head assembly, and the entrance point at which this winding begins is marked (
13). Further, after the magnetic tape (1) is wrapped around the rotating head assembly by the predetermined angle,
The outlet leaving the rotary head assembly and thus leaving it is designated by (14). The intermediate part between the inlet part (13) and the outlet part (14) is denoted by (15).
). Note that (16) is a terminal board shield case that houses a relay board that relays signals between the fixed side low retransformer (701) and the signal processing device.

Therefore, since the lead groove (202) is formed with a slope (downward slope) away from the rotating cylinder (4) from the inlet part (13) to the outlet part (14), the magnetic At the entrance part (13), most of the tape (1) in the width direction is located on the rotating cylinder (4) side, and as it approaches the exit part (14), it is located on the fixed cylinder (2) side in the width direction.
) side becomes larger.

By the way, the rotary cylinder (4) has, for example, 1800 r
, p, m, because it rotates at high speed, the entrance part (13
) from the rotating cylinder (4) as shown by the arrow (17).
Air flows in between the magnetic tape (1) and the exit part (1).
4) flows in as shown by the arrow (18), an air flow is generated on the outer circumferential surface of the rotating cylinder (4), and this air flows between the outer circumferential surface of the rotating cylinder (4) and the magnetic tape (1). film(
19) (Fig. 8) is formed. And this air film (1
9) is not uniform over the entire circumference of the rotating cylinder (4), and as shown in Figure 8 (a), the thickness of the magnetic tape 9) is not uniform over the entire circumference of the rotating cylinder (4), and as shown in Fig. 8 (a), air flows between the outer peripheral surface of the rotating cylinder (4) and the magnetic tape (1). Most of the magnetic tape (1) flows into the rotating cylinder (4).
It is thickest at the inlet part (13) located on the side, and gradually becomes thinner as it approaches the outlet part (14), as shown in FIGS. 8(b) and (c). In addition, in the outlet part (14), the pressure drop due to air outflow causes the magnetic tape (1) to
is drawn towards the rotating cylinder (4), which is also responsible for the thin air film (19) at the outlet (14).

[Problem to be solved by the invention] The rotary head assembly of the conventional magnetic recording/reproducing device is as follows.
During operation, an air film (19) is formed around the rotating cylinder (4). ) becomes smaller toward the outlet section (14). Furthermore, since the magnetic tape (1) travels while being wrapped around the fixed cylinder (2), friction between the magnetic tape (1) and the fixed cylinder (2) causes the entrance portion (1) to
The tape tension at the outlet (14) is greater than the tape tension at the outlet (14) in 3), and the thickness of the air film (9) decreases from the inlet (13) to the outlet (14) as described above. Coupled with this, the contact pressure of the magnetic tape (1) against the magnetic spatula F (6) increases from the inlet section (13) to the outlet section (14), and the magnetic spatula L'' (6)
) and the magnetic tape (1), there was a problem that the recording and reproduction of signals were uneven.

This invention was made in order to solve the problem of the conventional one, and the thickness of the air film formed between the rotating cylinder and the magnetic tape within the range where the magnetic tape is wound around the rotating head assembly. It is an object of the present invention to provide a magnetic recording/reproducing device which has uniformity in signal recording and reproduction without unevenness.

[Means for Solving the Problems] In order to achieve the above object, in the magnetic recording/reproducing apparatus of the present invention, the outer circumferential surface of the rotary head assembly and the magnetic tape are connected at an exit portion where the magnetic tape leaves the rotary head assembly. a first side surface spaced from and extending along the outer circumferential surface of the rotating head assembly and a first side surface spaced from and extending along the magnetic tape within a space formed therebetween; An air flow control member having a second side surface is provided.

[Function] In the magnetic recording and reproducing device configured as described above,
An air flow control member suppresses the free flow of air from the outlet to equalize the air pressure between the magnetic tape and the outer circumferential surface of the rotating head assembly at the outlet with the air at the inlet, reducing the air film thickness. equalization between the outlet section and the inlet section.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a plan view of a rotary head assembly and its surroundings in a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a right side view of FIG. 1. Reference numerals are given and explanations thereof are omitted.

In the figure, (20) is an air flow control member, and this air flow control member +4 (20) is connected to the outer circumferential surface of the rotary head assembly at the exit portion (14) where the magnetic tape (1) leaves the rotary head assembly. An arcuate shaped space is provided in the triangular space (21) formed between the tape (1) and extends along the outer circumferential surface of the rotary head assembly at a constant distance from the outer circumferential surface of the rotary head assembly. The first aspect (
20a) and a linear second side surface (20a) spaced apart from and extending along the magnetic tape (1).
0b) and a tip (20
c) has a sharp shape. This air flow control member (20) has a height (larger than the width of the magnetic tape (1)).
H), and is fixedly supported by the terminal board shield case (16) by a connecting member' (22) so as to protrude vertically beyond the upper and lower edges of the magnetic tape (1).

Thus, the airflow control member (20) is located within the triangular space (21) between the outer peripheral surface of the rotary head assembly and the magnetic tape (1), thereby allowing the airflow control member (20) to pass through the triangular space (21) as shown in FIG. The air pressure between the outer peripheral surface of the rotary head assembly and the magnetic tape (1) near the outlet (14) acts as a resistor to block the airflow flowing out in the direction of the arrow (18). The entrance part (13)
The thickness of the air film (19) is made uniform between the outlet section (14) and the inlet section (13).

Further, by making the thickness of the air film (19) uniform, the contact pressure of the magnetic tape (1) against the magnetic head (6) is also made uniform between the inlet portion (13) and the outlet portion (14). Therefore, recording information on the magnetic tape (1) and reproducing information from the magnetic tape (1) can be performed by making the thickness of the air film (19) uniform and making the contact pressure uniform.
1) is performed evenly and uniformly over the entire length, and the recording and reproducing performance is improved over the conventional one. Moreover, the first and second side surfaces (20a), (20) of the air flow control member (2o)
b) has a shape extending along the outer peripheral surface of the rotary head assembly and the magnetic tape (1), respectively;
The airflow does not become turbulent due to the airflow control member (20), and the running of the magnetic tape (1) does not become unstable due to the provision of the airflow control member (20).

In the above embodiment, the air flow control member (20) is provided at the exact midpoint between the outer peripheral surface of the rotary head assembly and the magnetic tape (1), or as shown in FIG. It may be provided closer to the rotary head assembly, or it may be provided closer to the rotary head assembly as shown in FIG. Furthermore, the terminal board shield case (16) may be used for attachment, and may be attached to another fixed part. Further, although the air flow control member (20) projects upward and downward from the upper and lower edges of the magnetic tape (1), it may be provided only in the portion of the magnetic tape (1) near the rotating cylinder (4). Furthermore, the outer circumferential surface of the rotary head assembly at the exit portion (14) and the magnetic tape (1)
The air pressure between the outlet section (1
4), the magnetic tape (1) is attached to the magnetic head (6).
) by making the absolute value of the contact pressure smaller than the conventional one,
In the conventional type, problems arose due to the large contact pressure at the exit portion (14), namely, large wear and damage to the magnetic head (6) and magnetic tape (1); When the head (6) separates from the magnetic tape (1), the magnetic tape (1) vibrates, making it impossible to perform proper recording and playback.
1), the load on the drive motor (8) changes (decreases) greatly, causing uneven rotation of the rotating cylinder (4), which also solves the problem of not being able to perform proper recording and playback. can be suppressed.

[Effects of the Invention] As described above, according to the present invention, the air flow control member having a predetermined shape is provided at the exit portion where the magnetic tape leaves the outer peripheral surface of the rotary head assembly, which is an extremely simple configuration. This provides the effect of uniformly recording information and reproducing information from a magnetic tape over its entire length.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a rotary head assembly and its surroundings in a magnetic recording/reproducing apparatus according to an embodiment of the present invention;
2 is a right side view of FIG. 1, FIGS. 3 and 4 are plan views of main parts of other embodiments of the present invention, and FIG. 5 is a shaft of a rotary head assembly of a conventional video tape recorder. 6 is a plan view schematically showing the magnetic tape running path around the rotary head assembly of FIG. 5, FIG. 7 is a front view of FIG. 6, and FIG. 8A and 8B are diagrams showing the deformation of the magnetic tape at various parts around the rotating head assembly shown in FIG. FIGS. 8(c) and 8(c) respectively show the deformation of the magnetic tape at the center between the outlet section away from the rotary head assembly and the inlet section; FIG. In the figure, (1) is a magnetic tape, (2) is a fixed cylinder, (201) is its outer peripheral surface, (202) is a lead groove,
(4) is a rotating cylinder, (5) is a bearing, (6) is a magnetic head, (13) is an inlet part, (14) is an outlet part, (20)
is an air flow control member, (20a) is a first side thereof, (2
0b) is the second side surface, and (21) is the space. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A fixed cylinder that has a lead groove on its outer circumferential surface that guides the running of the magnetic tape, a rotating cylinder that is rotatably supported from this fixed cylinder via a bearing, and a rotating cylinder that is attached to this rotating cylinder and has a lead groove that guides the running of the magnetic tape. A magnetic recording and reproducing device having a rotating head assembly including a magnetic head for recording and reproducing information on a running magnetic tape,
The lead groove is formed with a slope so as to move away from the rotary cylinder from an inlet portion where the magnetic tape begins to be wound around the rotary head assembly toward an outlet portion where the magnetic tape leaves the rotary head assembly, wherein at the outlet portion A first side surface extending along the outer circumferential surface of the rotary head assembly at a distance from the outer circumferential surface of the rotary head assembly and the magnetic tape within a space formed between the outer circumferential surface of the rotary head assembly and the magnetic tape. A magnetic recording and reproducing apparatus comprising: an airflow control member having a second side surface spaced from the magnetic tape and extending along the magnetic tape.