JPH0855391A - Rotary head device - Google Patents

Abstract

PURPOSE:To stably travel a tape at the time of its high speed traveling by surely supplying an air film between the tape and an upper drum. CONSTITUTION:The device is provided with the fixed upper drum 1, a rotary middle drum 2, a fixed lower drum 3 and a lead along which the tape is traveled. The middle drum 2 is provided with two dummy heads HDM consisting of hardly wearable material, e.g. a ceramic material at an angular interval of 180 deg.. The dummy head HDM is so arranged as to be close to the lower edge 1E of the upper drum 1 and not to be projected out of the middle drum 2 to the side of the upper drum 1. In addition, the head width of the dummy head HDM is set larger than the head width of a signal head to suppress the wear. The tape 9 is bumped on and raised by the dummy head HDM, and since the lower edge 1E of the upper drum is convered with a foot part of a tent shape of the raised tape 9, the air film is surely supplied between the tape 9 and the upper drum 1, and hence the stable traveling of the tape can be performed at the high speed traveling time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head device of a medium drum rotary type having a reproducing head whose head position is movable in the rotational axis direction, that is, a dynamic tracking head (DT head).

[0002]

2. Description of the Related Art FIG. 4 shows a configuration example of a conventional rotary head device for a VTR. In the figure, 1 is the upper drum,
2 is a middle drum and 3 is a lower drum. The rotary head device is of a medium drum rotary type, and the upper drum 1 and the lower drum 3 are fixed. Reference numeral 4 is a drum support, and 5 is an upper drum holder. Leads (steps) 6 are formed on the peripheral surface of the lower drum 3 along which the magnetic tape runs.

The middle drum 2 has recording heads HRA, HRB,
Two pairs of erase heads HER and reproducing heads HPA, HPB are arranged at an angular interval of 180 ° (only one set is shown). In this case, the recording heads HRA and HRB can record, for example, a luminance signal, a color signal, and a digital signal in parallel on two inclined recording tracks on the tape. On the other hand, the reproducing heads HPA and HPB can reproduce, for example, a luminance signal, a chrominance signal, and a digital signal in parallel from two inclined recording tracks on the tape.

The reproducing heads HPA and HPB are constructed as DT heads in which the head position is movable by using a bimorph or the like in the head base portion. For example, when the variable speed reproduction from + 3 × speed to −1 × speed is performed, the reproducing head H
The head positions of PA and HPB are controlled in the direction of the rotation axis so that the reproducing heads HPA and HPB do not scan across the inclined recording track, and the generation of noise bars is prevented. In addition,
The reproducing heads HPA and HPB are adapted to scan the inclined recording tracks on the tape prior to the recording heads HRA and HRB.

Also, in this rotary head device, a slip ring is used as a signal passing means in addition to the rotary transformer, and 7 is a slip ring portion. For example, a rotary transformer transfers a recording signal and a reproduction signal, and a slip ring transfers a DT head drive signal and a power supply. Reference numeral 8 is a drum motor for rotating the middle drum 2.

[0006]

In the rotary head device of the example of FIG. 4, since the reproducing heads HPA and HPB are configured as DT heads, the lower edge 1E of the upper drum 1 and the lower drum 3 are formed.
The distance from the upper edge 3E is relatively large. Further, the reproducing heads HPA and HPB have the above-mentioned +3 times speed to -1.
The lower edge 1E of the upper drum 1 other than during double speed variable speed reproduction
And the upper edge 3E of the lower drum 3 are located substantially in the middle. In this case, especially when the amount of protrusion of the head becomes small, as shown in FIG. 5, the tent-shaped skirt portion of the tape 9 due to the raising of the reproducing heads HPA and HPB does not reach the lower edge 1E of the upper drum 1, The air film 10 is insufficient on the upper drum 1 side. Therefore, when the tape 9 runs at high speed, air film breakage easily occurs, the difference in tape tension between the inlet and the outlet of the drum increases, and stable running of the tape becomes difficult.

Here, in FIG. 5, 11 is a DT head to which reproducing heads HPA and HPB are attached.
The DT head 11 is composed of bimorph members 11a and 11b which are vertically arranged at a predetermined interval, and a chip mounting member (beak) 11c which is connected to the bimorph members 11a and 11b and to which the reproducing heads HPA and HPB are mounted.

Even if the reproducing heads HPA and HPB are not configured as DT heads and the distance between the lower edge 1E of the upper drum 1 and the upper edge 3E of the lower drum 3 is not so large. When the height of the tent shape of the tape 9 becomes low due to the lift of the reproducing heads HPA and HPB due to the abrasion of the head, the air film 10 becomes insufficient on the upper drum 1 side in the same manner, and when the tape 9 runs at high speed, Film breakage easily occurs.

On the lower drum 3 side, the diameter of the lower drum 3 is smaller than that of the upper drum 1 because the leads 6 are provided on the lower drum 3 in order to generate a force for pressing the tape 9 against the leads 6. The air film 12 is easier to form than the upper drum 1 side.

The present invention provides a rotary head device which ensures stable supply of an air film between a tape and a fixed drum and enables stable running of the tape during high speed running.

[0011]

A rotary head device according to a first aspect of the present invention is a rotary head device of a middle drum rotary type, in which a dummy head is arranged in the middle drum so as to be close to an edge of the upper drum or the lower drum. It is a thing.

The rotary head device according to the invention of claim 2 is
In the invention of claim 1, the dummy head is made of a ceramic material.

The rotary head device according to the invention of claim 3 is
In the invention of claim 1, the dummy head has a wider head width than a signal system head such as a recording head or a reproducing head.

The rotary head device according to the invention of claim 4 is
In the invention of claim 1, the dummy head is arranged so as not to project to the upper drum side and the lower drum side from the middle drum.

The rotary head device according to the invention of claim 5 is
The invention of claim 1 is characterized by comprising a reproducing head whose head position is movable in the rotational axis direction.

[0016]

According to the first aspect of the present invention, the dummy head is arranged in the middle drum so as to be close to the edge of the upper drum or the lower drum, and the tent-shaped skirt portion of the tape formed by raising the dummy head is the upper drum or. It will come to the edge of the lower drum. Therefore, the air film is reliably supplied between the tape and the upper drum or the lower drum, the air film is not broken when the tape runs at high speed, and the tape can be stably run at high speed. .

According to the second aspect of the invention, since the dummy head is made of a ceramic member, the amount of wear of the dummy head can be reduced. Therefore, it is possible to maintain the air film supply effect of the dummy head until the signal system head such as the recording head or the reproducing head is worn and the middle drum is replaced.

According to the third aspect of the invention, the dummy head has a wider head width than a signal system head such as a recording head or a reproducing head, so that the wear amount of the dummy head can be reduced. Therefore, it is possible to maintain the air film supply effect of the dummy head until the signal system head such as the recording head or the reproducing head is worn and the middle drum is replaced.

In the invention of claim 4, since the dummy head is arranged so as not to project to the upper drum side and the lower drum side with respect to the middle drum, the dummy head of the upper drum or the lower drum is replaced when the middle drum is replaced. It may prevent contact with the edge.

According to a fifth aspect of the present invention, the reproducing head is provided, the head position of which is movable in the direction of the rotation axis. In this case, the distance between the edges of the upper drum and the lower drum is relatively large, and the skirt of the tent shape of the tape due to the signal system head being lifted up does not cover the edges of the upper drum and the lower drum, but a shortage of air film is likely to occur. Since the tent-shaped skirt of the tape is raised by the dummy head and hangs on the edge of the upper or lower drum, the air film can be reliably supplied between the tape and the upper or lower drum in this case as well. .

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, parts corresponding to those in FIG. 4 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, HDM is a dummy head, and two dummy heads are arranged on the middle drum 2 with an angular interval of 180 ° (only one is shown).

The dummy head HDM is disposed close to the lower edge 1E of the upper drum 1 as shown in FIG. However, it is arranged so as not to project from the middle drum 2 to the upper drum 1 side. The head width wd of the dummy head HDM is
It is set larger than the head width w of the recording heads HRA and HRB and the reproducing heads HPA and HPB. Incidentally, the recording head H
If the head width w of a signal system head such as RA, HRB or the reproducing heads HPA, HPB is increased, the contact with the tape 9 becomes poor and the spacing loss increases. Therefore, it is possible to increase the head width w so much. Can not. In the case of the dummy head HDM, since recording / reproduction is not actually performed,
There is no limitation on the head width like the signal system head.

Further, since the dummy head HDM does not actually perform recording / reproducing, it is formed of a material which is not easily worn, for example, a ceramic material. The amount of protrusion of the dummy head HDM to the outside is considered in consideration of damage to the tape 9, and for example, the recording heads HRA, HRB and the reproducing head HPA,
It is equivalent to the amount of HPB protrusion. Others of this example are configured similarly to the example of FIG.

In this example, the lower edge 1 of the upper drum 1
The tape 9 is tapped up by the dummy head HDM arranged close to E, and the tent-shaped skirt portion of the tape 9 is hooked on the lower edge 1E of the upper drum 1 as shown in FIG. The air film 10 is surely supplied between the drum 1 and the drum 1. Therefore, tape 9
The air film will not be broken during high speed running, and stable tape running during high speed running becomes possible. In FIG. 3, reference numeral 13 is a head base portion to which the dummy head HDM is attached.

Further, in this example, the dummy head HDM
Is composed of a material that is hard to wear, for example, a ceramic-based member, so that the wear amount of the dummy head HDM can be reduced.
Further, since the dummy head HDM has a wider head width than signal heads such as the recording heads HRA and HRB and the reproducing heads HPA and HPB, the wear amount thereof can be further reduced. Therefore, the air film supply effect by the dummy head HDM can be maintained until the signal system head is worn and the middle drum 2 is replaced.

Further, in this example, the dummy head HDM
Is arranged so as not to project from the middle drum 2 to the upper drum 1 side, so that it is possible to prevent the dummy head HDM from coming into contact with the lower edge 1E of the upper drum 1 when the middle drum 2 is replaced.

The above embodiment is provided with reproducing heads HPA and HPB as DT heads, and the upper drum 1 and the lower drum 3 are provided.
The present invention is applied to a rotary head device in which the edge distance between the upper drum 1 and the lower drum 3 is relatively narrow, although the present invention is not provided with a DT head. The same can be applied to the rotary head device. In that case, the tent shape of the tape 9 is lowered due to the lifting of the signal system head due to the abrasion of the signal system head, and the skirt portion thereof is the lower edge 1E of the upper drum 1.
If it is easy to run out of air film,
By raising the dummy head HDM, it is possible to reliably supply the air film between the tape 9 and the upper drum 1.

In the above embodiment, the middle drum 2
The dummy head HDM is arranged close to the lower edge 1E side of the upper drum 1, but similarly, the dummy head HDM is arranged close to the upper edge 3E side of the lower drum 3 of the middle drum 2. The air film can be reliably supplied between the tape 9 and the lower drum 3.

Further, in the above-mentioned embodiment, the intermediate drum 2
Although the two dummy heads HDM are arranged at an angular interval of 180 ° in the above, it is a matter of course that three or more dummy heads HDM may be arranged at a finer interval.

[0030]

According to the first aspect of the present invention, the dummy head is disposed in the middle drum so as to be close to the edge of the upper drum or the lower drum, and the tent-shaped skirt portion of the tape is formed by raising the dummy head. Since it will be applied to the edge of the upper drum or the lower drum, the air film is reliably supplied between the tape and the upper drum or the lower drum, and the air film will not run out at high speed running of the tape, The tape can be stably run at high speeds.

According to the second aspect of the present invention, since the dummy head is made of a ceramic member, the amount of wear of the dummy head can be reduced, and the signal system head such as the recording head and the reproducing head is worn and the middle drum is The air film supply effect by the dummy head can be maintained until it is replaced.

According to the third aspect of the present invention, the dummy head has a wider head width than a signal system head such as a recording head or a reproducing head. Therefore, the amount of wear of the dummy head can be reduced, and the recording head or the reproducing head can be reduced. It is possible to maintain the effect of supplying air film by the dummy head until the signal system head is worn out and the middle drum is replaced.

According to the invention of claim 4, since the dummy head is arranged so as not to project to the upper drum side and the lower drum side with respect to the middle drum, the dummy head is replaced by the dummy head when replacing the middle drum. It is possible to prevent contact with the edge of.

According to the invention of claim 5, there is provided a reproducing head whose head position is movable in the rotational axis direction,
The distance between the upper and lower drum edges is relatively large, and the tent-shaped skirt of the tape does not reach the edges of the upper and lower drums due to the signal system head being lifted up, and air film shortage easily occurs, but the dummy head Since the tent-shaped skirt portion of the tape by hitting up the drum hits the edge of the upper drum or the lower drum, the air film can be surely supplied between the tape and the upper drum or the lower drum also in this case.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a rotary head device according to the present invention.

FIG. 2 is an enlarged view showing a main part of the example of FIG.

FIG. 3 is a diagram showing a tape contact state of a dummy head.

FIG. 4 is a diagram showing a configuration example of a conventional rotary head device.

FIG. 5 is a diagram showing a tape contact state of a reproducing head.

[Explanation of symbols]

 1 Upper drum 2 Middle drum 3 Lower drum 6 Lead 9 Tape 10, 12 Air film HRA, HRB Recording head HPA, HPB Reproducing head HDM Dummy head

Claims (5)

[Claims] 1. A rotary head device of a medium drum rotary type, wherein a dummy head is disposed in the middle drum so as to be close to an edge of an upper drum or a lower drum. 2. The rotary head device according to claim 1, wherein the dummy head is made of a ceramic material. 3. The rotary head device according to claim 1, wherein the dummy head has a wider head width than a signal system head such as a recording head or a reproducing head. 4. The rotary head device according to claim 1, wherein the dummy head is arranged so as not to project from the middle drum toward the upper drum side and the lower drum side. 5. The rotary head device according to claim 1, further comprising a reproducing head whose head position is movable in the rotational axis direction.