JPS62146424A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To correct the change of a distance between a rotary head and a non-rotating head in accordance with the temperature change by contacting the rotary head slidably with a video track of a herical scanning type VTR, and providing a displacing means consisting of a piezoelectric element on the non-rotating head to bring into contact the non-rotating head slidably with a control track. CONSTITUTION:On a tape-like recording medium 3, the oblique video track and the control track are formed on its center part and peripheral part respectively, the rotary head is slidably contacted with the video track and the non- rotating audio control head 116 is also brought into slidably contact with the control track. In said constitution, an actuator consisting of a laminate piezoelectric element is arranged between a control head 116b fitted to a supporting member 110 and the member 110 and displaced by the output of a temperature sensor consisting of a thermocoupler. Consequently, even if environmental temperature is changed, the change of the distance between the rotary head and the non-rotating head can be corrected and a reproduced output can be stabilized.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a magnetic recording/reproducing device, and more particularly, to a magnetic recording/reproducing device, which uses a rotating head to record information on a tape-shaped recording medium (hereinafter referred to as tape) running along a guide drum. The present invention relates to a magnetic recording and reproducing apparatus, such as a helical scan video tape recorder (hereinafter referred to as VTR), which performs recording.

[Prior Art] Conventionally, a tape is run along the circumferential surface of a drum for a tape guide, and information such as image information is recorded on the tape by a plurality of parallel tracks formed diagonally with respect to the tape running direction. In addition, magnetic recording and reproducing devices such as helical scan type VTRs that record with a rotating head are already in widespread use. The tape running system in such a magnetic recording/reproducing apparatus, for example in a VH8 system VTR, is constructed as shown in FIG. That is, as shown in the figure, the tape 3 drawn out from the supply reel 2 of the tape cassette 1 is transferred from the tension regulator 4 to each tape guide 5.6 to the full-width erasing head 7 to the guide roller 8 to each loading tape guide 9.10. Drum 11 → Each loading tape guide 12.13 → Guide roller 14 → Audio erase head 15 → Audio control head 16 → Tape guide 17 → Capstan 18 and pinch roller 19,
The winding reel 20 is configured to reach the take-up reel 20 through the winding reel 20. As is well-known, the drum 11 has a plurality of rotating rads 11a facing the periphery of the lower surface of the upper drum.

11b is provided, and image signals are recorded on the tape 3 by this rotary head. In such a magnetic recording/reproducing device, the distance from the position where the tape 3 leaves the drum 11 to the audio control head 16 is as follows:
It is standardized according to the system such as VH8 or β.

This will be explained using FIG. Figure 6 Gi VT
FIG. 3 is a diagram showing an information recording pattern on a tape in R. Facing the upper side edge of the tape 3 running in the direction shown by the arrow 30, a second channel audio track (R channel) 32 and a first channel
A channel audio track (L channel) 31 is formed along the longitudinal direction of the tape 3. Further, a control track 33 is formed in the longitudinal direction facing the lower edge of the tape 3. In the area between the first channel audio track (L channel) 31 and the control track 33, there are a plurality of parallel tracks for recording video signals in a direction inclined with respect to the running direction of the tape, as shown in the figure. is formed.

The plurality of parallel tracks are formed by alternating first channel video tracks 34, 34 corresponding to the first field of one frame image and second channel video tracks 35, 35 corresponding to the second field. It has become. As schematically shown in the figure, the control head 16b of the audio control head 16 corresponds to the control track 33,
The first channel video track 34.34 has a rotary head 11a, and the second channel video track 34.
5.35 respectively correspond to the rotary head 11b. On such a tape pattern, the distance from the 180° exit of the second channel video track 35.35 to the control signal pulse, i.e. the position where the tape starts to leave the rotary head 11b corresponding to the second channel video track 35.35. from the control head 16b
Distance X to the hend gap when viewed on the tape
are determined by standards according to each method. This distance is necessary for the rotary heads 11a and 11b to accurately trace the first channel video track 34.34 and the second channel video track 35.35, respectively, based on the control signal pulse from the control track 33. This is because it needs to be kept constant. If this X value is not constant, compatibility with other devices will not be achieved.

[Problems to be Solved by the Invention] However, when the environmental temperature changes, the tape also expands and contracts accordingly, so the above-mentioned xi changes. Depending on the amount of change, there is a possibility that the rotating heads 11a and 11b will not be able to accurately trace the video track, resulting in disturbances in the reproduced image.

The present invention has been made in view of this point, and even if the environmental temperature changes significantly, the X value will change, or the distance between the rotating head and the non-rotating head will change accordingly as seen on the tape. It is an object of the present invention to provide a magnetic recording/reproducing apparatus of this type that can obtain stable reproduction output by correcting .

[Means for Solving the Problems 1] The present invention provides a magnetic recording/reproducing apparatus using a tape-shaped recording medium, in which a non-rotating head (control head in the example of the VTR described above) provided independently of a rotating head is provided. It is supported so that it can be displaced by a displacement means that responds to an external signal.

[Function] By making the displacement means respond to an external signal such as an output signal of a temperature sensor, the distance measured along the tape running path from the position where the tape leaves the rotating head to the non-rotating head can be measured. This adjusts the X value defined on the tape as described above (or the equivalent distance on the tape between the rotating head and the non-rotating head) so that the tape expands and contracts with changes in environmental temperature. It is possible to appropriately correct for changes caused by this.

[Embodiments] Examples of the present invention will be described in detail below with reference to the drawings. FIG. 1(A) and FIG. 1(B) are diagrams showing main parts of an embodiment of the present invention. In particular, Figure 1 (A) is a view of the head viewed from the tape sliding surface side, and Figure 1 (B) is a view of the head seen from the tape sliding surface side.
) is a view of the head viewed from the top side. The apparatus of this embodiment also has a tape running system including a rotating head and a drum, which is almost the same as that of the general VTR described with reference to FIG. . In FIG. 1(A) and FIG. 1(B),
The audio control head 116 as a non-rotating head includes an audio head 116a and a control head 116b. This audio control head 116 is attached to a support member 110 fixed at a predetermined location within the magnetic recording/reproducing apparatus via a piezoelectric element type actuator 100 as a displacement means. Audio control head 11 as shown
The tape 3 is made to run in sliding contact with the tape 3, and the audio head 116 is attached to each predetermined portion of the tape 3.
Audio signals and control signals are respectively recorded and reproduced by the control head 116a and the control head 116b. As the piezoelectric element type seven actuator 100, for example, an actuator made of a known laminated piezoelectric element can be applied. In this example, actuator 10o is configured to respond to the output of a temperature sensor as described below. FIG. 2 is a block diagram of a regulating circuit that drives a piezoelectric actuator based on the output of a temperature sensor.

Temperature sensor 20 such as thermocouple, resistance temperature detector, thermistor, etc.
The output of 0 is input to the scaling circuit 201, converted into a voltage signal having a predetermined linear correlation with the measured temperature, and then input to one input terminal of the comparison circuit 202. The output of the reference voltage generator 203 is input to the other input terminal of the comparator circuit 202. The output of the comparator circuit 202 is amplified by the piezoelectric element type drive circuit 204 to drive the actuator 1 described above.
00.

The apparatus according to the embodiment of the present invention described above with reference to FIGS. 1(A), 1(B), and 2 operates as follows. First, if the magnetic recording/reproducing apparatus is installed in an environment with a predetermined reference temperature (for example, a temperature of 20° C., which is equivalent to normal room temperature), the temperature sensor 200 is activated in the adjustment circuit shown in FIG. The output value, therefore the output value of the scaling circuit 201, is equal to the output value of the reference voltage generator 203, the output value of the comparison circuit 202 is zero, and therefore the output of the piezoelectric element type drive circuit 204 is also zero, and the actuator 100 is The distance (thickness) between both end faces is maintained equal to a predetermined reference value. Therefore, the position of the audio control head 116 supported by the piezoelectric actuator 100 as a displacement means is also maintained at the reference position corresponding to the reference temperature, and the tape 3 is moved to the rotating head (see FIG. 1 (A).
) and not shown in FIG.
)It has become. When the environmental temperature rises above the reference value from the above-mentioned state, the tape 3 elongates accordingly. That is, the distance X mentioned above becomes X+ΔX. At this time, the output value of the temperature sensor 200 in FIG. 2 also increases in accordance with the increase in the detected temperature, and therefore a difference occurs between the output value of the scaling circuit 201 and the output value of the reference voltage generator 203. Therefore, the output value of the comparator circuit 202 increases in the positive direction, and therefore the piezoelectric element drive circuit 204 drives the actuator 100 in a direction in which the distance between its both end faces increases. In the device of the present invention, when the seven cutuators 100 are displaced in the direction of increasing the distance as described above,
The above-mentioned distance also increases to X + ΔL (six directions in the figure). It goes without saying that the configuration is such that ΔL = ΔX. The above is based on the environmental temperature. This is a case where the adjustment displacement amount of the distance -Δ[(arrow 8 direction in the figure) is the change in distance I!l1iX due to tape contraction -ΔX even when the environmental temperature decreases. Therefore, in the device of the present invention, even if the tape 3 expands or contracts due to a change in the environmental temperature, the actuator 100 operates in response to this and adjusts the distance 11L as described above. For example, the synchronization relationship between the video signal recorded on the video track of the tape 3 and the audio signal or control signal recorded on the audio track or control track is maintained constant.

Next, what is shown in FIG.
This is a modification of the embodiment described with reference to Figure (B). In FIG. 3, parts corresponding to those in FIG. 1 (A>) and FIG. Instead of an actuator 101 that is displaced in the lamination direction, an actuator 101 made of a laminated thickness shear piezoelectric element is used.As the actuator 101 made of a laminated thickness shear piezoelectric element, for example, a piezoelectric actuator already proposed by the applicant of the present invention is used. It is recommended to apply a displacement device (Japanese Unexamined Patent Publication No. 59-211819).As disclosed in detail in the above publication, the actuator 101 in FIG. Therefore, this actuator 101 is inserted between the side surface of the audio control head 116 on the control head 116b side and the fixing member 111 having a surface substantially parallel to the same side surface. It is arranged.

The apparatus of FIG. 3 as described above also has the same effect as that of the embodiment described with reference to FIGS. It has the same effect as the position.

Next, what is shown in Fig. 4 is shown in Fig. 1 (A) and Fig. 1 (B).
) is yet another embodiment of the device. In FIG. 4, corresponding parts to those in FIGS. 1(A) and 1(B) are indicated by the same reference numerals, and a detailed explanation thereof will be omitted, but in this example, the actuator is a bimorph element known as an actuator. The following actuator 102 is applied. As shown in the figure, the bimorph element straddling this actuator 10 has a longitudinal direction perpendicular to the tape running direction between the upstream side surface of the audio control head 116 and the surface of the fixing member 112 when viewed in the tape running direction. It is arranged by a method such as directional adhesion. As is well known, this type of bimorph actuator 102 is displaced in the direction of rotation around its fixed end on the fixed member 112 side, but by selecting a sufficiently long arm length, the audio control head 116 can be displaced so as to be substantially parallel to the running direction of the tape 3.

Even in the case of this example, the same adjustment circuit as that explained with reference to FIG. 2 may be applied as an adjustment circuit for driving the actuator 100. Therefore, the device shown in FIG. 4 also has the same functions and effects as the devices shown in FIG. 1 (A) and FIG. 1 (B).

[Effects of the Invention] According to the present invention, even if the environmental temperature changes significantly, there is no change in the X value in the VTR, or a similar change in the distance between the rotating head and the non-rotating head as seen on the tape. It is possible to realize this type of magnetic recording/reproducing apparatus which can correct the difference and obtain stable reproduction output.

[Brief explanation of drawings]

1(A) and 1(B) are diagrams showing essential parts of an embodiment of the present invention, FIG. 2 is a block diagram showing an actuator drive circuit in the device of the present invention, and FIGS. 3 and 4. The figures show other embodiments of the present invention, and FIG. 5 shows a general V
FIG. 6 is a diagram showing a tape running system of a TR, and FIG. 6 is a diagram showing an information recording pattern on a tape in a VTR. 3... Tape-shaped recording medium, 11a, 11b...
Rotating head, 100, 101. 102... Actuator (displacement means), 116... Audio control head (non-rotating head) (Cause (A) Figure 1 (B) Figure 3 Figure 4

Claims (3)

[Claims] (1) A drum for guiding the tape-shaped recording medium along its circumferential surface during the running system of the tape-shaped recording medium;
In a helical scan type magnetic recording and reproducing device, the non-rotating head includes a rotating head whose tip rotates approximately along the circumferential surface of the drum, and a non-rotating head provided independently of the rotating head. 1. A magnetic recording and reproducing device characterized in that it is displaceably supported by a displacement means responsive to an external signal. (2) The magnetic recording and reproducing apparatus according to claim 1, wherein the displacement means includes a piezoelectric element. (3) The magnetic recording/reproducing apparatus according to claim 1, wherein the displacement means responds to the output of a temperature sensor.