JPH03280238A - Rotary head type recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent twisting of a tape by setting up a rotary drum to be turned and inclined to a traveling reference plane by an angle of the sum of a helical angle of winding the tape and a guide adjusting angle of an outlet or an inlet guide. CONSTITUTION:A magnetic tape 3 is guided by the inlet guide 4 and the output guide 5, and is wound around the outer circumferential surface of a rotary head drum at a helical angle S as slantly over an angle of nearly 360 deg.. A head 6 is brought into contact with the tape 3 at P-point. Then, the tape 3 is separated from the outer circumferential surface of the rotary drum to the guide 5 on a tangential line passing the P-point. Then, the rotary head drum is on this P-point and a center axis l of the drums 1 and 2, and is set up by turning itself around a line connecting the P-point and a point at the same height as an axis to be inclined to the traveling reference plane (r) by the sum angle S + alpha of the helical angle S can be guide adjusting angle alpha on the reference plane (r). By this method, since all over the tape after the guide 5 can be orthogonal to the reference plane (r), the tape is free from twisting, and damage on the tape edges can be diminished.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a rotary head type recording/reproducing device such as a helical scan VTR, and in particular, the tape winding around the drum is performed using a tape with a corner of 3606 mm. This invention relates to a rotary head type recording/reproducing device using a rotary head drum similar to that of the present invention.

(Prior Art) In a rotary helical type recording/reproducing device, such as a helical scan VTR, a magnetic tape is wound diagonally around the outer circumferential surface of a rotary head drum and is run while the tape is passed through a magnetic head called a rotary head. bring into contact. The rotating head drum consists of a rotating drum 1 and a stationary drum 2 coaxially arranged as shown in FIG. It is mounted on the rotating drum 1 as shown in FIG. The magnetic tape 3 is guided by an entrance guide 4 and an exit guide 5,
It travels while being wound diagonally around the outer peripheral surfaces of the rotating drum 1 and the fixed drum 2, and comes into contact with the magnetic head.

The mounting position of the rotating head drum in a VTR varies depending on the angle and tape running method, but the winding is different for VTRs with angles close to 360 degrees (for example, 1-inch type C-VTR). In many cases, the drum is tilted so that the tape coming out of the drum is approximately parallel to the running reference plane. For example, in FIG. 7, the tape 3 is placed at an angle θ (type C-VT
In R, it is wound over approximately 346'). The tape 3 is guided by the entrance guide 4 and wound around the drum from point A, leaves the drum at point B, is folded back by the exit guide, and then guided to the next traveling element of the tape traveling system. The entrance side folded part 31 and the exit side folded part 32 of the tape 3 are formed by winding the tape 3 around the artificial guide 4 and the exit guide 5, respectively.

FIG. 8 shows these tape folded portions 31 and 32 omitted. The tape 3 is wound around the drum at an angle S (referred to as the helical angle) with respect to the circumferential direction of the drum, and is led away from the drum to the exit guide 5 at a tangent B1 passing through point B. The magnetic head 6 is attached to the rotating drum 1 at a predetermined height, and comes into contact with the tape 3 at a point P on the tangent line B1 as the rotating drum 1 rotates.

In a rotary head drum where the angle θ is close to 360°, the direction cosine of the axis 41 of the entrance guide 4 and the axis 51 of the exit guide 5 in space are similar. An example of selecting a tape running system in such an apparatus is disclosed in, for example, Japanese Patent Publication No. 59-27982. Here, the angle at which the tape is not wrapped (360
It is shown that by tilting the drum by a predetermined amount with respect to the reference plane at a line that bisects the angle (°-〇), the entry and exit log guides are tilted slightly in different directions. Furthermore, the centerline of the tape stretched between the inclined exit guide and the vertical guide of the next running element or between the inclined entrance guide and the vertical guide of the next running element is parallel to the reference plane, but not parallel to the centerline. The perpendicular lines in the width direction of the tape are not perpendicular to the reference plane, but change direction one after another along the length of the tape, so-called "twist".
is allowed.

This method has the problem of elongation of the tape edges, and has the disadvantage that the distance between the tape guides must be kept long so as not to exceed the elastic limit of the tape material.

Another method is to take advantage of the fact that the direction cosines of the entry/exit guides are similar, for example, by making the axis 51 of the exit guide 5 orthogonal to the travel reference plane, and tape the axis 41 of the entrance guide 4 which is slightly inclined. A method is known in which the inclination of the tape 3 is corrected in the tape running system before reaching the entrance guide 4 so that the tape 3 can be wound without twisting, or a method in which the axis 41 is made perpendicular to the running reference plane. Figure 9 is an example of the former, where the helical angle is defined by a line perpendicular to the plane of the figure that connects point P and a point on the central axis R of the drum and at the same height as point P. The drum is tilted by a corresponding angle S. As a result, a line P1 that passes through point P and is inclined at an angle S with respect to line B1, and the exit guide 5
Both axes 51 are perpendicular to the traveling reference plane r. Therefore, it is considered that the tape after the folded portion 32 on the exit guide 5 side becomes perpendicular to the travel reference plane r.

On the other hand, in assembling a VTR, in order to make the envelope waveform of the reproduced RF signal output from the video head into a rectangular shape as shown by the solid line in FIG. The part 42 is extended in the direction of arrow M (the direction approaching line P1), and the exit guide 5
Adjustments may be made to increase the tape tension along the trajectory of the front 6 by extending the lower side 52 of the tape in the direction of the arrow N (direction away from the line P1). In other words, in the longitudinal direction of the inclined track 101 (arrows 102, 1) in the track pattern on the tape 3 shown in FIG.
Adjustments are made to give tape tension in the direction 03). When such tension is not applied, the envelope waveform of the reproduced RF signal becomes as shown by the broken line in FIG. 10, and the waveform of the portions corresponding to the vicinity of both ends of the inclined track 101 becomes dull.

However, as a result of such adjustment, the shaft 51 of the exit guide 5 is inclined at an angle S+α with respect to the central axis of the drum, as shown in FIG. 11, and is no longer orthogonal to the travel reference plane r. The angle α in this case is called the guide adjustment angle.

FIG. 13 is a plan view of the space between the exit guide 5 and the next traveling guide 8 when such adjustment is made.
Since the axis 51 of the exit guide 5 is inclined with respect to the running reference plane (a plane parallel to the plane of the paper in FIG. 13), when the running guide 8 is made perpendicular to the running reference plane, the tape 3 is screwed as shown in the figure. It will be done. In a tape running system, if the tape is allowed to twist over a short distance, there is a problem that the tape tension varies in the width direction of the tape and the edges of the tape are easily damaged. In order to avoid this, there is a restriction that the position of the running guide 8 must be sufficiently separated from the exit guide 5, which results in an increase in the size of the tape running system. In order to avoid twisting the tape, a guide with a certain predetermined direction cosine (this is called a direction cosine conversion guide) is prepared.
There is a way to return the tape to a state parallel to the running reference plane, but providing such a direction cosine conversion guide is
This is undesirable because it makes the tape running system more complicated, larger, and more expensive.

(Problem to be Solved by the Invention) As described above, in the conventional technology, when a guide adjustment angle is applied to the exit guide and the exit guide to apply tension to the tape in the longitudinal direction of the inclined track, both guides Since both of them are no longer perpendicular to the running reference plane, the tape after the exit guide or the tape before the entrance guide is twisted and the edges of the tape are likely to be damaged.

Further, if a direction cosine conversion guide is provided to avoid such tape twisting, there are problems in that the tape running system becomes complicated and large, and the cost becomes high.

In the present invention, even when the entrance guide and the exit guide are provided with a guide adjustment angle for applying tension to the tape in the longitudinal direction of the inclined track, either one of the guides can be made perpendicular to the running reference plane, It is an object of the present invention to provide a rotary head type recording/reproducing device that can eliminate twisting of the tape after the exit guide or before the entrance guide without providing a direction cosine conversion guide.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention has a rotating head drum attached such that the head protrudes from the outer peripheral surface. In a rotary head type recording and reproducing device that performs recording and reproducing while running a tape wrapped at a predetermined helical angle (S) around an entrance guide and an exit guide, the tape on the rotary head drum moves toward the exit guide or entrance guide side. The sum of the helical angle (S) and the guide adjustment angle (α, β) of the exit guide or entrance guide, with the line connecting the point on the tangent away from the outer peripheral surface of the drum and the center axis of the rotating head drum as the axis. It is characterized in that the rotating drum is rotated and tilted by an angle with respect to the running reference plane.

(Function) In this way, the helical angle S and the guide adjustment angles α and β of the exit guide or entrance guide are set relative to the running reference plane of the rotating drum.
By turning and tilting the guide by the sum angle S+α or S+β, the exit guide or the entrance guide immediately intersects perpendicularly to the travel reference plane. Therefore, since the tape after the exit guide or the tape before the entrance guide is perpendicular to the running reference plane, it is possible to attach the running guide after the exit guide or before the entrance guide perpendicular to the running reference plane, thereby avoiding twisting of the tape. It will be done.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

1 and 2 are a side view and a plan view of a rotary head drum section in a rotary head type recording/reproducing apparatus according to an embodiment of the present invention. The rotating head drum consists of a rotating drum 1 and a stationary drum 2 coaxially arranged. Hereinafter, the rotating drum 1 and the fixed drum 2 will be collectively referred to as the rotating head drum. The magnetic head 6 is attached to the rotating drum 1 so that its tip slightly protrudes from the outer peripheral surface of the rotating drum 1.
can be attached to. The magnetic tape 3 is guided by an entrance guide 4 and an exit guide 5, and is wound diagonally around the outer peripheral surface of the rotary head drum over an angle close to 360° (for example, 346°) and at a helical angle S.

Note that, in FIG. 1, similarly to FIG. 8, the inlet side and outlet side tape folded portions (31.degree. 32) in FIG. 7 are not shown.

Head 6 contacts tape 3 at point P. Also, tape 3
departs from the outer peripheral surface of the rotary head drum toward the outlet guide 5 on a tangent line passing through point P. Then, the rotary head drum is moved around the running reference plane r, with the line n shown in FIG. It is installed on the travel reference plane r, tilted by an angle S+6 times, which is the sum of the helical angle S and the guide adjustment angle α.

FIG. 3 is a diagram showing the state before tilting the rotary head drum. Before tilting the rotary head drum, the drum center axis g is perpendicular to the running reference plane r, and the tape 3 is
As shown in Figure (a), the rotary head is raised at a helical angle S from the rotary head drum with respect to the running reference plane r. In this case, the third
As shown in Figure (a), by tilting the outlet guide 5 by a helical angle S with respect to an axis g' parallel to the drum center axis g, within a plane passing through a tangent to the drum's outer peripheral surface, the tape 3 is attached to the rotating head of the drum. and is wound around the exit guide 5 without any force (without twisting). From this state, in order to make the envelope waveform of the reproduced RF signal square as described above,
As shown in FIG. 3(b), the outlet guide 5 is tilted with respect to the axis g' by a helical angle S and an additional guide adjustment angle α in a plane passing through a tangent to the outer peripheral surface of the drum. As a result, the outlet guide 5 is eventually inclined with respect to the axis g' by S+α within a plane passing through a tangent to the outer peripheral surface of the drum. Specifically, for example, S-2,5914'αY0.4'', S10α
is approximately 3@.

In the present invention, the rotary head drum is further rotated and tilted by S+α about the line n shown in FIG. 2 from the state shown in FIG. 3(b). If the rotary head drum is tilted in this way, that is, if the drum axis g is tilted by S+α with respect to the line n, then the axis g' parallel to the drum axis g as shown in FIG. 3(b).
The outlet guide 5, which is inclined by S+α in a plane passing through a tangent to the outer peripheral surface of the drum, is also rotated by S+α in the direction opposite to the direction of the inclination. As a result, the axis m of the exit guide 5
is perpendicular to the traveling reference plane r. Therefore, the tape (folded part 32) after being wrapped around the exit guide 5 is
Since it is perpendicular to the running reference plane r, the guide 7 next to the exit guide 5 shown in FIG. 2 and all the guides after it can be installed perpendicular to the running reference plane r.

However, in this embodiment, since the entrance guide 4 has a certain direction cosine, in order to make the tape before the entrance guide 4 perpendicular to the running reference plane, it is necessary to provide a direction cosine conversion guide in the running system. This is the same as before.

Next, a further improved embodiment of the above embodiment will be described.

As shown in FIG. 3(a), before the rotary head drum is tilted, the tape 3 is at a helical angle S with respect to the running reference plane r.
is rising. Therefore, when the rotary head drum is tilted by an angle of S+α as shown in FIG. is descending at an angle of (S+α)-8-α and is not parallel to the running reference plane r.

FIG. 4 is a plan view showing an embodiment in which the tape 3 exiting the rotary head drum is perpendicular to and parallel to the running reference plane r. In this embodiment, after the rotary head drum and the exit guide 5 are tilted at an angle S+α, the axis m of the exit guide 5 is tilted by the guide adjustment angle α in the opposite direction to the traveling direction of the tape 3. At this time, the axis p of the rotary head drum is also tilted by α, so that the direction cosines of the rotary head drum and the exit guide 5 always maintain the same relationship.

FIG. 5 is a side view showing the surface of the tape 3 in FIG. 4. As is clear from this figure, the traveling reference plane r
The tape 3, which has descended at an angle of α, wraps around the exit guide 5 tilted by α, and then becomes perpendicular to and parallel to the running reference plane r.

According to this embodiment, the rotary head drum and the exit guide 5 are first tilted at an angle of S + α with the line n as the axis, and then the exit guide 5 is tilted by α in the direction of travel of the tape 3. Although this requires adjustment and is troublesome in terms of design, the tape 3 after the exit guide 5 can be made perpendicular to and parallel to the running reference plane r, which has the effect of simplifying the tape running system. has.

In the above embodiments, the tape exiting the rotary head drum is perpendicular to the running reference plane r, but in the present invention, it is also possible to arrange the tape entering the rotary head drum to be perpendicular to the running reference plane r. Literature: "Broadcasting Technology" 1982.6, p.
559, the rotating head drum is rotated at a helical angle (2' 35
An example in which the helical angle S and the guide adjustment angle β of the entrance guide 4 are 6, which connects the point Q where the tape on the rotary head drum separates from the outer peripheral surface of the rotary head drum toward the entrance guide 4 side and the central axis g of the rotary head drum by an angle equal to the sum of The rotary head drum is tilted with respect to the running reference plane r with a line as an axis.This allows the tape 3 entering the rotary head drum to be orthogonal to the running reference plane r.Therefore, all tapes before the entrance guide 4 It becomes possible to install the guide perpendicular to the running reference plane r.However, in this embodiment, since the exit guide 5 has a certain direction cosine, the tape after the exit guide 5 is made perpendicular to the running reference plane r. In order to achieve this, it is necessary to provide a direction cosine conversion guide in the running system, as in the conventional case.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to make all the tapes after the exit guide or before the entrance guide perpendicular to the running reference plane, without providing a special direction cosine conversion guide. Therefore, with an inexpensive and simple configuration, twisting of the tape can be eliminated and damage to the tape edges can be reduced.

[Brief explanation of drawings]

FIG. 1 is a side view showing the structure of a rotary head drum according to a first embodiment of the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a state before tilting the rotary head drum of the same embodiment. A side view for explanation, FIG. 4 is a plan view showing the configuration of a rotary head drum according to a second embodiment of the present invention which is an improvement over the first embodiment, and FIG. A side view of the tape, FIG. 6 is a side view showing the configuration of a rotary head drum section according to a third embodiment of the present invention, FIG. 7 is a perspective view of a conventional rotary head drum section, and FIG. FIG. 9 is a side view, FIG. 10 is a diagram showing a preferred envelope waveform of the reproduced RF signal in a VTR, FIG. 11 and IJ12
The figure shows the inclined track pattern on the tape and the direction in which tension is applied to explain the necessity of giving guide adjustment angles to the artificial guide and the exit guide. It is a top view which shows a guide. DESCRIPTION OF SYMBOLS 1... Rotating drum, 2... Fixed drum, 3... Tape, 4... Entrance guide, 5... Exit guide, 6...
...head, 7,8...guide, p...drum shaft,
m...Exit guide axis, n...rotation axis, r...travel reference plane, S...helical angle, α, β...guide adjustment angle.

Claims (2)

[Claims] (1) Rotation in which recording and playback is performed while the tape is wound around the outer circumferential surface of the rotary head drum at a predetermined helical angle by an entrance guide and an exit guide, and the tape is wound around the outer circumferential surface of the rotary head drum, which has a rotating drum attached so that the head protrudes from the outer circumferential surface. In a head-type recording/reproducing device, the helical angle is defined by the line connecting the central axis of the rotary head drum and the point on the tangent line where the tape on the rotary head drum leaves the outer peripheral surface of the rotary head drum toward the exit guide side. A rotary head type recording/reproducing device characterized in that a rotary drum is rotated and tilted relative to a travel reference plane by an angle equal to the sum of the guide adjustment angle of the exit guide. (2) Rotation in which recording and playback is performed while the tape is wound around the outer circumferential surface of the rotary head drum at a predetermined helical angle by an entrance guide and an exit guide, and the tape is wound around the outer circumferential surface of the rotary head drum, which has a rotating drum attached so that the head protrudes from the outer circumferential surface. In a head-type recording/reproducing device, the helical angle is defined by the line connecting the central axis of the rotary head drum and the point on the tangent line where the tape on the rotary head drum leaves the outer peripheral surface of the rotary head drum toward the entrance guide side. A rotary head type recording/reproducing device characterized in that a rotary drum is rotated and tilted relative to a running reference plane by an angle equal to the sum of the guide adjustment angle of the entrance guide.