JPH0444615A - Rotary head device - Google Patents

Abstract

PURPOSE:To reduce damage for a tape and to enable satisfactory recording and reproducing by providing a recessed part, which rotary shaft and length in a peripheral direction are shorter than those of a rotary drum, near a window part on the outer peripheral and cylindrical face of the rotary drum. CONSTITUTION:A rotary drum 2 is freely rotatably supported through the shaft to a fixed drum 1, and at a window part 8 provided on the outer peripheral and cylindrical face of the drum 2, a head 3 is arranged while being protruded for a prescribed amount from the outer peripheral and cylindrical face of the drum 2. A recessed part 9 is provided near the window part 8 on the outer peripheral and cylindrical face of the drum 2 over a phase advanced from the same phase as the head 3 at a rotary phase. Since tape attracting and tape vibration generating parts are made closest to the rotary drum while providing the recessed part 9 on the outer peripheral and cylindrical face of the rotary drum, it is possible to prevent a tape 4 from colliding the drum 2 by attracting and vibrating the tape. Thus, the noise caused by collision is reduced, and sound quality is improved in the case of recording.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotary head device used in a recording and reproducing apparatus, such as a video tape recorder, which records or reproduces signals on a tape-like medium.

2. Description of the Related Art In a rotary head device used in a conventional helical scan type video tape recorder, etc., a tape is wound around a stationary drum and a rotating drum for approximately 180° or 270°, and the head is used to wrap the tape in the longitudinal direction of the tape. Video signals are recorded and played back diagonally.

Further, a thin air layer is formed between the tape and the rotating drum, and the tape floats above the rotating drum via this air layer. In addition, the tip of the head that performs recording and playback is
It protrudes from several μm to several tens of μm from the outer cylindrical surface of the rotating drum. Therefore, when the head is in contact with the tape, the tape is lifted up by the head so as to be separated from the outer cylindrical surface of the rotating drum, and a negative pressure is generated near the head due to the presence of a window around the head. The tape is attracted to the outer cylindrical surface of the rotating drum, and a large pressure is exerted between the head and the tape. Further, the tape is attracted by the outer circumferential cylindrical surface of the rotating drum on the side of the phase that precedes the head in the rotational phase compared to the side of the phase that follows.

A conventional rotary head device will be described below.

FIG. 10 is a perspective view of a conventional helical scan type rotary head device. FIG. 11 is a schematic diagram of the rotary head device viewed from above the rotating shaft of the rotary drum. 1st
In Figure 0, a rotating drum 2 is rotatably supported on a fixed drum 1 via a shaft (not shown), and a window 8 provided on the outer cylindrical surface of the rotating drum 2 is opened by a predetermined amount from the outer cylindrical surface of the rotating drum. A head 3 is disposed to protrude. The tape 4 is spirally wound around the outer cylindrical surfaces of the stationary drum 1 and the rotating drum 2 for approximately 180' by two guide posts 6.7, and is wound around the tape guide groove 5 provided on the outer periphery of the stationary drum 1. The vehicle then travels in the direction shown by arrow B. The head 3 is fixed to the rotating drum 2 and is attached to the rotating drum 2.
At the same time, the tape 4 rotates in the direction shown by arrow A, starts contacting the tape 4 from near the bottom end, and comes out from near the top end of the tape 4. As shown in FIG. 11, the tape 4 is connected to the rotating drum 2.
The tape 4 floats from the rotating drum 2 through a thin air layer between 0 and 3, and the tip of the head 3 protrudes from the outer cylindrical surface of the rotating drum 2 by several μm to several tens of μm. Being separated.

Problems to be Solved by the Invention However, in such a conventional configuration, the tape is run,
When recording a video signal on a tape by rotating the head, or when playing back a video signal on a tape, when the tape 4 and the head 3 are in contact as shown in FIG. Due to the protrusion, the tape 4 is attached to the rotating drum 2
Since a window is formed near the outer cylindrical surface of the tape 4, negative pressure is generated between the tape 4 and the rotating drum 2.
The tape 4 is attracted to the outer cylindrical surface of the tape 4, and a large pressure is exerted between the tape 4 and the spatula 3. Also,
The tape 4 floats above the rotating drum 2 through a thin layer of air. If this air layer is thin, the tape 4 will be damaged by scratches or the like due to the rotation of the rotating drum 2, so the air layer must be thick. Therefore, the pressure acting between the rotating drum 2 and the tape 4 needs to be low. Further, in order to perform recording and reproduction, the pressure acting between the head 3 and the tape 4 must be increased to a predetermined amount. In other words, there have been contradictory issues of lowering the pressure acting between the tape 4 and the rotating drum 2 and increasing the pressure acting between the tape 4 and the head 3 to a predetermined amount.

Further, FIGS. 12 and 13 schematically show a side view and a plan view of the rotary head device in the vicinity of the separation point when the head separates from the tape. When the head 3 separates from the tape 4, the portion of the tape 4 that precedes the spatula P3 in the rotational phase collides with the rotating drum 2 due to the negative pressure generated between the rotating drum 2 and the tape 4. Further, vibrations are generated in the tape 4 due to the shock caused by the sudden removal of the pressure between the head 3 and the tape 4, and these vibrations propagate on the tape to generate vibrations in the upper end portion C of the tape. This tape vibration causes the tape 4 to collide with the rotating drum 2.

The problem was that the collision between these two components caused noise, which affected the sound quality during recording.

In view of the above problems, the present invention reduces the pressure that acts between the tape and the rotating drum when the head and tape are in contact, and increases the pressure that acts between the tape and the head to a predetermined amount. The present invention provides a method. It also provides a method for suppressing the noise generated when the head and tape are separated from each other and improving the sound quality during recording.

Means for Solving the Problems A first technical fishing means of the present invention for solving the above problems is such that the length in the direction of the rotation axis of the rotating drum is located on the outer peripheral cylindrical surface of the rotating drum and in the vicinity of the window. This is because at least one recessed portion is provided, the circumferential length of which is smaller than the circumferential length of the rotary drum.

A second technical means of the present invention for solving the above problems is that the length in the rotational axis direction is smaller than the length in the rotational axis direction of the rotating drum on the outer circumferential cylindrical surface of the rotating drum and near the window part, and the length in the rotational axis direction is smaller than that of the rotating drum. At least one of the four parts has different shapes depending on the distance between
This is due to the establishment of one.

Effect: With the above-described structure, the present invention can reduce the pressure that acts between the tape and the rotating drum when the head and tape are in contact, and increase the pressure that acts between the tape and the head. Therefore, damage to the tape can be reduced and good recording and playback can be performed.

It also eliminates collision between the tape and the outer cylindrical surface of the rotating drum due to tape suction and tape vibration when the head separates from the tape, making it possible to reduce noise generation and improve sound quality during recording. be.

Embodiments Hereinafter, rotary head devices according to embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a rotary head device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken on a plane passing through the recess and perpendicular to the axis of the rotating drum when the head of the rotating head device in the first embodiment is separated from the tape. In FIG. 1, a rotating drum 2 is rotatably supported on a fixed drum 1 via a shaft (not shown), and a window 8 provided on the outer cylindrical surface of the rotating drum 2 is provided on the outer cylindrical surface of the rotating drum 2. The head 3 is disposed so as to protrude by a predetermined amount. Further, the tape 4 is spirally wound around the outer cylindrical surfaces of the fixed drum 1 and the rotating drum 2 over a length of approximately 180' by two guide posts 6.7, and a tape guide groove 5 provided on the outer periphery of the fixed drum 1. The vehicle travels in the direction shown by arrow B along the road. head 3
is fixed to the rotating drum 2, rotates together with the rotating drum 2 in the direction shown by arrow A, starts contacting the tape 4 near the bottom end, and comes out near the top end of the tape 4. The head 3 protrudes from the rotating drum 2 and the stationary drum 1 by several micrometers to several tens of micrometers, thereby separating the tape 4 from the outer cylindrical surface of the rotating drum 2. The recess 9 is provided near the window 8 on the outer cylindrical surface of the rotary drum 2 from the same rotational phase as the head 3 to the preceding phase, and this position is located near the window 8 when the head 3 separates from the tape 4. This is the part where the suction part and the tape vibrating part are closest to the outer cylindrical surface of the rotating drum. Since the tape suction part and the vibration generating part are very close to each other, in this embodiment they are the same recessed part. Run the tape 4 on the tree 1,
When recording a video signal on a tape by rotating the head 3, or when playing a video signal on a tape,
As shown in FIG. 1, the head 3 starts contacting the tape 4 near the bottom end, and starts pulling out the tape 4 near the top end. When the tape 4 and the head 3 are in contact, the head 3
Due to the protrusion of the tape 4, the tape 4 is lifted away from the outer cylindrical surface of the rotating drum, and in the vicinity thereof, the window 8
Because of the negative pressure generated between the tape 4 and the rotating drum 2, the tape 4 is attracted to the outer cylindrical surface of the rotating drum, and pressure is applied between the tape 4 and the head 3. When the head 3 pulls out the tape 4 from near the upper end of the tape 4, vibrations are generated in the tape 4 due to this tape suction and the impact of sudden loss of pressure acting between the tape 4 and the rotating drum 2, which propagate on the tape 4. Vibration occurs at the top end of the tape. However, since the recess 9 is provided on the outer cylindrical surface of the rotating drum where the tape suction and tape vibration generation portion is closest to the rotating drum, it is possible to avoid collision between the tape 4 and the rotating drum 2 due to tape suction and tape vibration. becomes. By configuring as described above, it is possible to reduce noise caused by collision.

FIG. 3 is a perspective view of a rotary drum of a rotary head device according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram of the state of the tape in the vicinity of the window when viewed from above the axis of the rotary drum when recording and reproducing are performed with the rotary drum device of the second embodiment.

The recess 9 is provided near the window so as to have a long sleeve in the circumferential direction of the rotating drum. When this device runs the tape 4 and rotates the head 3 to record a video signal on the tape, or to reproduce the video signal on the tape, the head 3 starts contacting the tape 4 from near the bottom end. , the tape 4 is pulled out from near the top end. And tape 4 and head 3
is in contact with the tape 4 due to the protrusion of the head 3.
is lifted apart from the outer cylindrical surface of the rotating drum, and in the vicinity thereof, a window 8 is formed, so negative pressure is generated between the tape 4 and the rotating drum 2, and the tape 4
is attracted to the outer cylindrical surface of the rotating drum, and pressure is applied between the tape 4 and the head 3. Here, the recess 9 is provided near the window, and a part of the air layer between the rotating drum 2 and the tape 4 flows into the recess 9. Therefore, the suction force between the rotating drum 2 and the tape 4 is high in the vicinity of the rotating drum window 8 where the recess 9 is provided, and is low in the area where the recess 9 is not provided. In other words, the pressure acting between the tape 4 and the head 3 can be increased up to a predetermined amount, and the pressure acting between the rotating drum 2 and the tape 4 can be reduced. With the above configuration, it is possible to reduce damage to the tape and to perform good recording and reproduction.

FIG. 5 is a perspective view of a rotating drum of a rotating head device according to a third embodiment of the present invention. The recess 9 is provided near the window 8 so that the width and depth become smaller as the distance from the head 3 increases. In this apparatus, when recording a video signal on the tape by running the tape 4 and rotating the head 3, or when reproducing the video signal on the tape, the attraction force between the rotating drum 2 and the tape 4 is as follows. It is high in the vicinity of the rotary drum window 8 where the recess 9 is provided, and it is low in the area where the recess 9 is not provided. Furthermore, the width and depth of the recess 9 are determined by the head 3.
As the distance between the tape 4 and the recess 9 approaches, the amount of air flowing into the recess 9 increases as the distance between the tape 4 and the rotating drum 2 approaches the head 3, and the suction force between the tape and the rotating drum 2 increases. The closer the distance to the head 3, the higher it becomes. In other words, the pressure acting between the tape 4 and the head 3 can be increased to a predetermined amount, while the pressure acting between the rotating drum 2 and the tape 4 can be lowered. More tape 4
The suction force between the rotary head 3 and the rotary head 3 can be changed continuously. Therefore, damage to the tape 4 can be reduced and good recording and reproduction can be performed. It is also possible to adjust the contact pressure between the head 3 and the tape 4 by changing the width and depth of the recess 9.

FIG. 6 is a perspective view of a rotary drum of a rotary head device according to a fourth embodiment of the present invention. The width and depth of the recess 9 are the same as the window 8.
In the vicinity of the head 3, the farther the distance from the head 3, the smaller the ink flow, and at the same distance from the head 3, the trailing side has a larger comb and rotation than the leading side in the rotation phase. It is provided all the way around the drum 2 in the circumferential direction, or all the way around the drum 2 except for the window part 8. When this device records a video signal on the tape by running the tape 4 and rotating the head 3, or when reproducing the video signal on the tape, when the tape 4 and the head 3 are in contact with each other, Due to the protrusion of the head 3, the tape 4 is lifted away from the outer cylindrical surface of the rotating drum, and in the vicinity thereof, a window 8 is formed, so that the tape 4 and the rotating drum 2 are separated from each other.
A negative pressure is generated between the tape 4 and the head 3, and the tape 4 is attracted to the outer cylindrical surface of the rotating drum, and pressure is exerted between the tape 4 and the head 3. Here, since the recess 9 has a deep width and depth near the window, the pressure between the head 3 and tape 4 can be increased to a predetermined amount, and the pressure between the rotating drum 2 and tape 4 can be lowered. . In addition, since the recess 9 is continuous over almost the entire circumference of the rotating drum,
Pressure changes are also continuous, reducing tape damage. Here, the width and depth of the recess 9 are such that the side trailing from the head 3 is larger than the side leading from the head 3 at the same distance from the head 3 in the vicinity of the window 8, and the distance from the head 3 is larger. Because it is designed to get bigger as it gets shorter,
The tape suction force on the trailing side of the head 3 in the rotational phase is greater than that on the leading side. Here, the contact between the tape 4 and the head 3 must be equal on the leading side and the trailing side in order to perform good recording and playback. Further, since the head 3 rotates, the tension of the tape 4 is low on the side preceding the head 3 and high on the side following the head 3 in the rotational phase due to friction between the head 3 and the tape 4. Therefore, in order to bring the head 3 and tape 4 into even contact on the leading and trailing sides, it is necessary to increase the suction force on the trailing side. Therefore, according to the above configuration, it is possible to make equal contact with the tape on the leading side and the trailing side of the head 3. With the above configuration, the pressure acting between the tape 4 and the head 3 can be increased to a predetermined amount, and the pressure acting between the rotating drum 2 and the tape 4 can be lowered. Since the change can be made continuous, damage to the tape 4 can be reduced and good recording and reproduction can be performed. Furthermore, the contact between the leading head 3, the trailing head 3, and the tape 4 can be made equal, thereby making it possible to perform good recording and reproduction.

FIG. 7 is a perspective view of a rotary drum of a rotary head device according to a fifth embodiment of the present invention. A large number of recesses 9 are arranged in the vicinity of the window 8 from the side leading to the head 3 to the side trailing the head 3. When this device records a video signal on the tape by running the tape 4 and rotating the head 3,
Alternatively, when reproducing a video signal on a tape, the tape suction force on the trailing side of the head 3 can be made larger than on the leading side, as in the fourth embodiment. Therefore head 3
It becomes possible to equalize the contact between the tape 4 and the head 3 on the leading side and the trailing side. With the above configuration, the pressure acting between the tape 4 and the head 3 can be increased to a predetermined amount, while the pressure acting between the rotating drum 2 and the tape 4 can be lowered. It becomes possible to reduce damage and perform good recording and reproduction.

Furthermore, it is possible to reduce changes in the contact state between the leading side and the trailing side of the head, thereby achieving good recording and reproduction.

FIG. 8 is a perspective view of a rotary drum of a rotary head device according to a sixth embodiment of the present invention. The recessed portion 9 is arranged around the entire circumference in the circumferential direction, or all the way around except for the window portion 8,
Its width and depth increase as it approaches the head 3, and it is disposed near the window 8. In this apparatus, when recording a video signal on the tape by running the tape 4 and rotating the head 3, or when reproducing the video signal on the tape, the recess 9 is smaller than that in the third embodiment. Since it is continuous over almost the entire circumference, the pressure changes between the tape 4 and the rotating drum 2 and between the tape 4 and the head 3 are continuous over almost the entire circumference, making it possible to prevent excessive load from being applied to the tape 4. .

FIG. 9 is a perspective view of a rotary drive of a rotary head device according to a seventh embodiment of the present invention. The recesses 9 are provided on the leading and trailing sides of the head 3 such that the obtuse angle side of the bent portion is on the head side. With this device, the tape 4 is run and the head 3 is
When recording a video signal on a tape by rotating the tape, or when reproducing a video signal on a tape, an air layer between the rotating drum 2 and the tape 4 is formed near the window 8 by the rotation of the rotating drum 2. Therefore, on the side preceding the head-3, the air flows toward the head 3, and on the side trailing the head-3, the air flows away from the head 3. Therefore, it is possible to reduce the tape suction force on the leading side of the head 3 and increase the tape suction force on the trailing side of the head 3.

With the above configuration, the pressure acting between the tape 4 and the head 3 can be increased to a predetermined amount, while the pressure acting between the rotating drum 2 and the tape 4 can be lowered. It becomes possible to reduce damage and perform good recording and reproduction. Furthermore, it is possible to reduce changes in the contact state between the leading side and the trailing side of the head and perform good recording and reproducing.

Effects of the Invention As described above, the present invention reduces the pressure that acts between the tape and the rotating drum when the head and tape are in contact, and reduces the pressure that acts between the tape and the head by a predetermined amount. This makes it possible to increase the height of the tape, reducing damage to the tape.
Furthermore, it is possible to perform good recording and reproduction.

Furthermore, it is possible to avoid collision between the tape and the rotating drum when the tape and the head are separated, and the noise generated at the time of collision can be reduced, thereby improving the sound quality during recording.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a rotary head device according to a first embodiment of the present invention, and FIG. 2 is a perspective view of a plane perpendicular to the axis of a rotary drum passing through a concave portion when the head in the same embodiment is detached from a tape. 3 is a perspective view of a rotating drum according to a second embodiment of the present invention, and FIG. 4 is a view from above the shaft of the rotating drum when recording and reproducing is performed with the rotating drum device of the same embodiment. A schematic diagram of the state of the tape near the window, FIG. 5 is a perspective view of a rotating drum in a third embodiment of the present invention, and FIG. 6 is a perspective view of a rotating drum in a fourth embodiment of the present invention. FIG. 7 is a perspective view of a rotating drum in a fifth embodiment of the present invention;
FIG. 8 is a perspective view of a rotating drum according to an eighth embodiment of the present invention, FIG. 9 is a perspective view of a rotating drum according to a seventh embodiment of the present invention, and FIG. 10 is a conventional helical scan type rotating head. A perspective view of the device; FIG. 11 is a schematic diagram of the rotating shaft of the rotary drum of a conventional rotary head device viewed from above; FIG. 12 is a conventional rotary head device near the separation point when the head separates from the tape. FIG. 13 is a schematic side view of the conventional rotary head device near the separation point when the head separates from the tape. 1... Fixed drum, 2... Rotating drum, 3
... head, 4 ... tape, 5 ... tape guide groove, 6.7 ... guide post, 8 ... window, 9 ... recess. Name of agent Patent attorney Shigetaka Awano Figure 110

Claims (2)

[Claims] (1) A fixed drum having a tape guide means for guiding a tape-shaped medium, a rotating drum that is coaxial with the fixed drum and rotatably supported, and a window provided on the outer cylindrical surface of the rotating drum. a head disposed to protrude a predetermined amount from the outer cylindrical surface of the rotating drum; A rotary head device comprising at least one recess whose circumferential length is smaller than the circumferential length of a rotary drum. (2) A fixed drum having a tape guide means for guiding a tape-shaped medium, a rotating drum that is coaxial with the fixed drum and rotatably supported, and a window provided on the outer cylindrical surface of the rotating drum. a head disposed to protrude a predetermined amount from the outer cylindrical surface of the rotating drum; A rotary head device comprising at least one recess whose shape differs depending on the distance from the head.