JPS6122377B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention utilizes a helical scan rotating head system.
Regarding noiseless high-speed playback equipment for VTRs,
The tape guide can be moved smoothly with a simple configuration.

In general, the traces on a tape recorded with a VHS VTR look like the one shown in Figure 1. In FIG. 1, reference numeral 1 denotes a magnetic tape, on which recording traces A1, B1, A2, B2, A3, . . . are formed by two rotating heads having mutually different azimuths. The recording traces A1, A2, . . . are caused by one rotating head A, and the recording traces B1, B2, . . . are caused by the other rotating head B. Arrow A indicates the running direction of the tape during recording, and arrow B indicates the scanning direction by the rotary heads A and B.

During normal playback, the tape 1 is run in the direction of arrow A at the same speed as during recording, and the rotating heads A and B are also run at the same speed as during recording, and the recorded traces A1, A2, . . . A, record trace
B1, B2, . . . were scanned by rotary head B, and recorded signals were reproduced by rotary heads A and B.

By the way, in the case of so-called cueing, in which a tape is run at high speed to obtain a reproduced image in order to search for specific screen information recorded on a tape, when the tape is run at 9x speed, scanning by rotating heads A and B is performed. The traces are now indicated by chain lines a and b. For example, rotating head A has recorded traces A6, B6, A7, B7, A8,
Scan B8, A9, B9, and A10 sequentially. When only the recording traces B6, B7, B8, and B9 hit the rotary head A during this scanning, no reproduced signal is obtained, only noise, and the reproduced signal shown in FIG. 2 is obtained from the rotary head A. In Figure 2, symbols a6, a
7, a8, a9, a10 are the above records respectively
These are from A6, A7, A8, A9, and A10.

When the tape is run at high speed as described above, the directions of the recording traces A1, B1, ... on the tape and the scanning traces a, b caused by the rotating heads A, B are different, and the noise component in the reproduced signal increases. There is a drawback.

In order to eliminate the above-mentioned drawbacks and to match the directions of the recording traces A1, B1, ... and the scanning traces a and b, the running direction of the tape relative to the rotational direction of the rotary heads A and B is changed as shown in Fig. It is possible to change it. In FIG. 3, reference numeral 1 denotes the above-mentioned tape, which is wrapped around the circumference of a well-known head drum 2 having rotating heads A and B over a distance of about 180°. The rotary heads A and B are attached to the upper side 3 of the head drum 2 and rotate together with the rotary heads, while the lower side 4 is fixed to a substrate or the like. code 5
is a lead guide fixed to the lower side of the head drum 2, and during normal playback, the tape 1 runs in the direction of arrow A with one edge of the tape 1 being lightly pressed against the lead guide 5.

Reference numerals 6 and 7 denote tape guides, which are fixed to the substrate at the entrance and exit sides of the tape 1 in the head drum 2. These tape guides 6 and 7 are formed in a cylindrical shape and have flanges 6a, 6b, 7a, and 7b that restrict movement of the tape 1 in the width direction. pressed against. This tape guide 6
When one edge of the tape 1 moves slightly apart as shown in FIG. 3 (as if pressing one edge of the tape 1 with the flange 6b), the running direction of the tape 1 changes as described above.

As explained above with reference to FIG. 3, the recorded traces A1 and B1 on the tape 1 can be matched with the scanned traces a and b. FIG. 4 shows a state in which the recording trace AI coincides with the scanning trace a of the rotary head A during high-speed running. At this time, if the running direction of the tape 1 is not changed, the scanning trace a will look like a chain line a'.

As in the fourth example above, when the scanning trace a becomes shorter than the recording trace A1, a part of the reproduced screen is missing. Furthermore, it is necessary to control the speed of the rotary head A so that the short scanning trace a is scanned in the same time as scanning the recording trace A1 during normal reproduction.

Although the above description relates to the rotary head A, substantially the same applies to the rotary head B.

Furthermore, in the above explanation, the case where the playback screen is obtained by running the tape 1 at high speed in the direction of arrow A is described. When a playback screen is obtained by running at high speed in the direction C, which is opposite to A, as shown in FIG.
The scanning traces of the rotary heads A and B with respect to A1, B1, .
A poor playback signal is played back. This record trace A1,
In order to align B1, . . . with the above-mentioned scanning trace, as shown in FIG.
is moved in the axial direction of the tape 1 by the flange 7b.
What is necessary is to press one edge of the lead guide 5 and separate the edge from the lead guide 5. In addition, in Figure 6, the third
The same reference numerals as those in the drawings indicate members having the same effect.

By the way, as mentioned above, by moving the tape guides 6 and 7 in the axial direction as shown in FIG. 3 or FIG. 6 and separating one edge of the tape 1 from the lead guide 5, the recording traces A1, B1, If an attempt is made to match the direction of the scanning traces of the rotating heads A and B, the following drawbacks will occur.

(1) Assuming that the tape 1 does not bend in the tape width direction (rigid body), the tape 1 will completely separate from the lead guide 5, and the tape 1 will not bend in the width direction of the tape.
Even if you are touching the flange part 7 at this time
a, 6a become separated from the other edge of the tape 1, and the movement of the tape 1 in the width direction cannot be restricted, making the running of the tape 1 unstable. This instability also occurs in the actual tape 1.

(2) In the actual tape 1, due to the difference in level between the upper side 3 and the lower side 4 of the head drum 2, it sag in the direction approaching the lead guide 5 (loss of linearity).
The part of the tape close to the lead guide 5 touches the lead guide. Due to this droop of tape 1, recording traces A1, B1,... on tape 1 are created.
It is also slightly curved, resulting in areas that do not match the scanning traces of the rotating heads A and B, and the S/N of the reproduced signal deteriorates.

A device shown in FIG. 7 can be considered as a device that eliminates such drawbacks. In Figure 7, the third
The same reference numerals as in the figures and FIG. 6 indicate the same elements. In FIG. 7, the tape guide 6 is moved in its axial direction, and one edge of the tape 1 is pressed by the flange 6b, and the edge is separated from the lead guide 5, leaving the above-mentioned recording mark.
The directions of A1, B1, . . . coincide with the directions of the scanning traces of the rotating heads A and B. Further, the tape guide 7 is moved slightly in its axial direction, and the other edge of the tape 1 is pressed by the flange 7a, so that one edge of the tape is sufficiently pressed beyond the point where it touches the lead guide 5. .

Due to the pressing of the other edge of the tape 1 by the flange 7a, the tape 1 receives a force that slightly rotates the tape 1 in the counterclockwise direction in FIG. The portion of the tape 1 that tends to sag away from the lead guide 5 is corrected, and the linearity of the tape 1 is improved. Further, since the tape 1 is pressed against the lead guide 5 at approximately one point by the flange 7a, movement in the width direction is also restricted, and the running of the tape 1 becomes stable. By improving the linearity of the tape 1, the aforementioned deterioration of S/N can be improved.

The present invention provides a high-speed playback device for a VTR that allows the tape guide to be easily moved as described above.

An embodiment of the present invention will be described below with reference to FIGS. 8 to 14.
The figure will be explained in detail.

FIG. 8 shows only the parts related to the present invention in a VTR. In FIG. 8, 2 is a head drum, which is mounted on a substrate (not shown) as is well known. 1 is the aforementioned magnetic tape, which is housed in a well-known cassette 8;
As is well known, as the inclined guide poles 9, 10 and the vertical guide poles 11, 12 move, they are pulled out from the cassette 1, and are wrapped around the head drum 2 as shown. Vertical guide pole 1
1 and 12 are brought into contact with stoppers 13 and 14 having V-grooves at the tape draw-out position, and held at that position. 15 and 16 are impedance rollers, 17 is a full width erase head, and 18 and 19 are
CTL, an audio head, 20 a capstan, 21 a pinch roller, 22 a tension pin, and 23 a tape guide, all of which are well known. Reference numerals 24 and 25 denote tape guides to be described later, which are implanted in arms 28 and 29 that are rotatably provided on the substrate with 26 and 27 as fulcrums.

The above vertical guide pole (tape guide) 11,
12 is constructed as illustrated for the pole 12 in FIG. 9, and is pressed into contact with the stopper 14. 9th
In the figure, reference numeral 30 is a base body associated with a well-known arm (not shown) that moves the pole 12 when the tape 1 is pulled out from the cassette 8 as described above, and is moved substantially together with the arm. A pole holder 31 is fixed to the base body 30, and a shaft 32 is slidably inserted through the holder.
This holder 31 has a female thread 3 concentrically with the shaft 32.
3 is provided, and a male thread 34 is screwed into the female thread. This male thread 34 also has a hole through which the shaft 32 is slidably inserted, and a recess 3 in the upper part.
5 is formed. Numerals 36 and 37 are flanges fixed to the shaft 32, and a guide roller 38 rotatably attached to the shaft 32 is disposed between these flanges 36 and 37. Further, a convex portion 39 is formed on the lower surface of the collar 37 and is loosely fitted into the concave portion 35 . The above-mentioned pole 12 is composed of the above-mentioned shaft 32, roller 38, holder 31, etc.
Note that 40 is a screw for preventing rotation of the screw 34.

The stopper 14 is fixed to the frame 41 fixed to the board by screws, and the stopper 14 is
4 are formed with the aforementioned V grooves 42 and 43, and the holder 31 is pressed into contact with these V grooves 42 and 43 by movement of the base body 30. Above stopper 14
A fine movement piece 44 that can be brought into contact with the upper end of the shaft 32 is integrally formed on the shaft 32, and the position of the fine movement piece 44 in the direction of the shaft 32 can be adjusted by a screw 45.
Reference numeral 60 is a collar fixed to the shaft 32, and a pressure spring 61 is interposed between the collar and the holder 31.

Tape guides 24 and 25 explained in FIG. 8 above
As shown in FIG. 10 for the tape guide 24, the tape guide 24 is installed in the arm 28, and a pin 53 is installed in the arm in the direction toward the plane of the paper, and is biased by a traction spring 58.

In the vertical guide pole 12, when the collar 37 is turned, the male screw 34 having the recess 35 fitted in the convex part 39 is rotated, and the collar 36 is connected to the holder 31.
The position of the pole 12 in the direction of the axis 32 of 37 is varied, and the position of the pole 12 during normal recording and reproduction is determined.
This position is fixed by screws 40.

The above-mentioned pole 12 corresponds to the tape guide 6 explained in FIG. This corresponds to the tape guide 7 described in FIG. Further, the tape guide 24 corresponds to the tape guide 7 described in FIG. 7 during cueing.

11 to 14 show a device for moving the poles 11, 12 and tape guides 24, 25 described in connection with FIGS. 8 to 10 above. In the figure, 20 is the above-mentioned capstan, a flywheel 62 is fixed to the capstan, and the flywheel is connected to the belt 63.
It is designed to be rotated by a capstan motor 64 via a well-known method. 65 is a pulley of the motor 64. This flywheel 62 is provided with projections 66a, 66b, 66c, and 66d at equal intervals. 67 is a detection arm, which is rotatably attached to a substrate (not shown) with 68 as a fulcrum. 69 is a traction spring, and arm 67
The arm 67 is held in a neutral position as shown in the figure. A detection lever 70 is rotatably attached to the arm 67 about a fulcrum 71, and is biased by a traction spring 72 stretched between the arm 67 and the arm 67. By rotating the detection lever 70 against the spring 72, the detection lever 70 approaches the top surface of the flywheel 62.
It is pressed by the projections 66a, 66b, 66c, and 66d. 73 is an electromagnet, and the arm 6
7, and the lever 70 is attracted by this excitation. 74 is a detection pin, which is connected to the arm 6.
It is fixed at 7.

Reference numerals 75 and 76 denote a cue plate and a review plate which are slidably attached to the substrate, respectively, with long holes fitted into guide pins 79 implanted in the substrate, and separate traction springs 77 and 78. are biased in opposite directions. These plates 75 and 76 have protrusions 82 and 83 that operate respective switches 80 and 81 by sliding, a pin 53 related to the tape guide 24 described above, and a pin 84 corresponding to the pin 53 in the tape guide 25. It has protrusions 85, 86 for operating the rollers 85, 86, respectively, and beveled edges 89, 90 for pushing up the rollers 87, 88 by sliding. Arms 91 and 92 are rotatably attached to the board using 93 and 94 as fulcrums, and the rollers 87 and 88 are attached to these arms 91 and 92, and leaf springs 95 and
96 is installed. Reference numerals 97 and 98 are traction springs, which are stretched between the substrate and the arms 91 and 92, and these springs 97 and 98 cause the arm 9 to
1 and 92, the rollers 87 and 88 are connected to the beveled edges 89 and 9.
It is biased so that it is pressed against zero. 99,10
0 is a tongue piece constituting a well-known push-button mechanism, etc., and plates 75 and 76 are connected to springs 77 and 7.
8, the above-mentioned tongue pieces 99, 10
0, the plates 75, 7 are moved to these sliding positions.
6 is locked so that plate 7 is held, and plate 7 is locked again.
5 and 76 against the springs 77 and 78, the lock is released and the plates 75 and 76 return to the position shown.

The shaft 32 of the pole 12 is mounted on the leaf springs 95 of the arms 91 and 92, and the shaft 101 corresponding to the shaft 32 of the pole 11 is mounted on the leaf spring 96.

The above figures 8 to 14 have been explained.
In a VTR, during cueing, the capstan 20 is rotated clockwise in FIG. 11, the tape 1 is pressed against the capstan 20 by the pinch roller 21, and the tape 1 is run at high speed.
At the start of this cue, the capstan 20 is first rotated clockwise at a low speed (same as during playback), and then the electromagnet 73 is energized. Due to this excitation, the lever 70 is rotated against the spring 72, and when the lever approaches the surface of the flywheel 62, it is pressed by one of the protrusions 66a to 66d, and the lever 70 and the arm 69 move around the fulcrum 68. The plate 75 is rotated counterclockwise against the center of the spring 69, and the pin 74 presses the plate 75. This pressing causes the plate 75 to slide against the spring 77, and is held in this sliding position by the tongue piece 99.
be locked down. Due to the above-mentioned sliding of the plate 75, the protrusion 85 separates from the pin 53, the tape guide 24 reaches the tape running path of the tape 1, and the roller 87 climbs the slanted edge so that the beam 91 resists the spring 97. This rotation causes the shaft 32 to be pushed up by the spring 95. As the shaft 32 is pushed up and the tape guide 24 reaches the tape running path, one edge of the tape 1 is pressed and separated from the lead guide, and the other edge is pressed, improving the linearity of the tape 1. be done. When the plate 75 is slid against the spring 77 as described above, the switch 80 is operated, thereby increasing the rotation of the capstan 20, for example, for high-speed running.

When the tape guide 24 reaches the running path of the tape 1 as described above, the other edge of the tape 1 is pressed by the upper collar of the tape guide 24, which is set in advance at a lower position than when the tape is running normally. Since the collar corresponding to the reference numeral 37 of the pole 12 in the pole 11 is located away from one edge of the tape 1 during normal running of the tape, the other edge of the tape 1 is pressed by the upper collar of the tape guide 24 described above. As a result, one edge of the tape 1 is further pressed against the position where it touches the lead guide, and the linearity of the tape 1 described above is obtained. Further, as the shaft 32 is pushed up, the pole 12 rises, and its collar 37 presses one edge of the tape 1, and this edge separates from the lead guide, causing the direction of the recording trace on the tape 1 to change to the rotating head. It almost matches the scan trace of .

Next, when a playback operation is performed in the queue state, the rotational speed of the capstan 20 is first slowed down (for playback), and then the electromagnet 73 is excited. Due to this excitation, the lever 70 is pressed by one of the protrusions 66a to 66d, the arm 67 is rotated counterclockwise, and the plate 75 is slid against the spring 77. As a result of this sliding, the tongue 99 disengages the chain line of the plate 76 as is well known, the plate is returned to the position shown by the spring 77, and the arm 67 is also returned to the neutral position shown by the spring 69.

Next, when a review operation is performed from this regeneration state, the flywheel is rotated counterclockwise at the speed during regeneration, and when the electromagnet 73 is subsequently energized, the lever 70 is pressed clockwise. The arm 67 rotates clockwise and the plate 76 slides against the spring 78. Due to this sliding, the roller 88 is pushed up by the beveled edge 90, and the protrusion 88 is pushed up by the beveled edge 90.
6 leaves pin 84. When the roller 88 is pushed up, the shaft 101 is pressed through the arm 92 and the spring 96, the pole 11 moves and one edge of the tape 1 is pressed, and the tape 1 is separated from the lead guide. Further, when the protrusion 86 separates from the pin 84, the tape guide 25 reaches the tape running path, the other edge of the tape 1 is pressed by the guide 25, and the linearity of the tape 1 is improved. In this way, the direction of the recording trace on the tape that is being run at high speed in the opposite direction is matched with the direction of the scanning trace of the rotary head.

Due to the above-mentioned sliding of the plate 76 against the spring 78, the plate 76 is locked in its sliding position by the tongue piece 100, and when the switch 81 is operated, the rotational speed of the capstan 20 becomes high. , the tape 1 is pressed against the capstan 20 by the pinch roller 21.

When a reproduction operation is performed in such a review state, the speed of the capstan 20 becomes a low speed for reproduction, and at this time the electromagnet 73 is excited. This excitation causes the lever 70 to move through the protrusions 66a, 66b,
66c and 66d, the arm 67 is rotated clockwise, the pin 74 slides the plate 76 against the spring 78, and the plate 76 is unlocked by the tongue piece 100.
The plate 76 is returned to the illustrated position by the spring 78, and the arm 67 is also returned to the illustrated neutral position by the spring 69, whereby the switch 81 is operated and the direction of rotation of the capstan 20 is changed clockwise to enter the playback state. becomes.

As explained above, according to the high-speed playback device for a VTR of the present invention, during high-speed playback, one edge of the tape is separated from the lead guide by one guide, and the rotating head runs the tape along the recording trace on the tape. The edge of the tape is pushed further by the other guide than the point where it touches the lead guide, and force is applied to the tape in the direction away from the lead guide using the point where the tape touches the lead guide as a fulcrum, and the head drum The linearity of the tape is improved by correcting the sagging of the tape toward the lead guide due to the difference in level between the upper and lower sides. Further, the tape is pressed against the lead guide at approximately one point, and movement in the width direction is restricted by the two guides, so that the tape runs stably. Furthermore, the guide is moved in accordance with the high-speed running direction of the tape by a movable member that is selectively moved according to the rotational direction of the flywheel, so that the tape can be run at high speed in either the forward direction or the reverse direction. The guide is automatically moved so that the rotary head scans along the recording trace on the tape. Therefore, stable reproduced images can be obtained during high-speed reproduction in either the forward direction or the reverse direction.

[Brief explanation of the drawing]

Figures 1 to 7 are used to explain the present invention; Figure 1 is a tape pattern diagram, Figure 2 is a reproduced signal waveform diagram, Figure 3 is a developed view of the vicinity of the tape drum, Figures 4 and 7 are diagrams of the present invention. Figure 5 is a tape pattern diagram, Figure 6
7 and 7 are exploded views of the vicinity of the head drum, FIGS. 8 to 14 show an embodiment of the present invention, FIG. 8 is a plan view, and FIG. 9 is a sectional view of the main parts.
Fig. 10 is an enlarged plan view of the main part, Fig. 9 is a sectional view of the main part, Fig. 10 is an enlarged plan view of the main part, Fig. 11 is a plan view of the main part, Fig. 12, Fig. 13, and FIG. 14 is a front view of the main parts. 1: tape, 2: head drum, 5: lead guide, 6, 7: tape guide, 62: flywheel.

Claims (1)

[Claims] 1. In a VTR having a head drum, the upper side of which is provided with a rotary head that rotates together with the rotary head, and the lower side of which is provided with a lead guide that is fixed and one edge of the tape can be brought into contact with the circumferential surface of the head drum. Separate guides are provided on the entrance side and the exit side, each having a circumferential surface that the tape comes into contact with and that limits the position of the tape in the width direction, and when the tape is played back at high speed, one of the guides is used. Guide one edge of the tape away from the lead guide so that the rotary head scans the tape along the recording trace on the tape, and the remaining guides guide the tape away from the lead guide. The other edge is guided so that one edge of the tape is pushed further than where it touches the lead guide, thereby applying a force on the tape away from the lead guide, and also in the direction of rotation of the flywheel. In a VTR, the guide is moved to a position where it presses one edge or the other edge of the tape depending on the high-speed running direction of the tape by a movable member that is selectively moved depending on the direction of the tape. High speed playback device.