JPS59104722A - magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate the use of a recording magnetic head and at the same time to improve the tracking accuracy with both recording and reproducing modes, by using an electrostrictive element for both recording and reproducing operations and providing a means which compensates the hysteresis displacement characteristics of an electric-machanical converting means. CONSTITUTION:When a recording truck is traced on a magnetic tape 1 by a magnetic head 3, a changeover switch 16 is changed to the side of a compensating signal generator 18 of a reproduction mode. The generator 18 applies the signals to electrostrictive elements 7 and 8 to give flexural deformations to the element 7 and 8 so that a magnetic head 6 traces the recording track in response to the traveling mode of the tape 1 by means of the displacement degree signals given from the elements 7 and 8 as well as the traveling mode signal given from a traveling mode generating means 21. Thus the head 6 traces the recording track on the tape 1. In this case, the head 6 is not held at the regular position on the tape 1 but has a shift. This shift is compensated by a compensating signal supplied from a record mode compensating signal generator 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic recording/reproducing apparatus in which a magnetic head is mounted on a rotating drum using electromechanical conversion means.

[Prior art]

In magnetic recording and reproducing devices, a magnetic head is attached to a rotating drum by electromechanical conversion means in order to improve image quality. This electromechanical conversion means exhibits a tracking function for tracking tracks recorded on the magnetic tape. As this electromechanical conversion means, an electrostrictive element such as a bimorph is generally used. The electrostrictive element has a displacement characteristic with hysteresis with respect to applied voltage. Therefore, when recording signals on a magnetic tape, it is difficult to accurately position the magnetic head. For example, in the case of a VTR, the track width is approximately 20
From the viewpoint of ensuring compatibility between devices, the positional deviation of the head during recording is required to be 2 to 3 μm or less.

Therefore, the magnetic head attached to the electrostrictive element is used only during reproduction, and another fixed head is used during recording.

[Purpose of the invention]

The present invention has been made based on the above-mentioned problems, and an object of the present invention is to provide a magnetic recording and reproducing device that can realize recording and reproducing using the same electrostrictive element and improve tracking accuracy.

[Summary of the invention]

In order to achieve the above object, the present invention provides a magnetic recording and reproducing apparatus in which a magnetic head is attached to a rotary drum 4 by an electromechanical conversion means, and information is recorded or reproduced on a magnetic tape wound around the outer periphery of the rotary drum. means for detecting the displacement amount of the electromechanical conversion means, and outputting a signal to the electromechanical conversion means for correcting the hysteresis displacement characteristic of the electromechanical conversion means during recording and reproduction based on the displacement amount of the electromechanical conversion means from the detection means. It is equipped with a control means to

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a drum portion of an example of the magnetic recording/reproducing apparatus of the present invention. In the figure, 1 is a magnetic tape, 2 is a rotating drum, and 3 is a fixed drum. The rotating drum 2 is a rotating shaft 4
is fixed. 5 is a bearing. A magnetic head 6 for recording and reproducing signals on the magnetic tape 1 includes an electrostrictive element 7,
It is attached to one end of 8. The other ends of the electrostrictive elements 7 and 8 are fixed to the rotating drum by fixing blocks 9 and 10. The electrostrictive elements 7.8 are bonded together and are bent and deformed by applying voltages in opposite directions to each other, causing the magnetic head 6 at the tip thereof to track the recording track. The electrostrictive elements 7 and 8 have displacement characteristics with hysteresis with respect to applied voltage. In order to detect the displacement of the electrostrictive elements 7 and 8, a capacitive displacement detector 11 is attached to the rotating drum 2 so as to face the electrostrictive element 7.

An output conductor 11A of this displacement detector 11 passes through a slip ring 12 provided on the rotating shaft 4 and is connected to a fixed brush 13. The fixed brush 13 is connected to the displacement detector 15 through the amplifier 14 . The displacement detector 15 is connected to a recording correction signal generator 17 or a reproduction correction signal generator 18 through a changeover switch 16. Changeover switch 16
is switched by the recording or playback signal. The changeover switch 16 in the illustrated state is connected to a recording correction signal generator 17 according to the recording signal. The recording correction signal generator 17 and the reproduction correction signal generator 18 are connected to the electrostrictive element 7.8 through an amplifier 19.20, respectively. The recording correction signal generator 17 applies a recording correction signal to the electrostrictive elements 7,'8 based on the displacement amount of the electrostrictive elements 7.8 from the displacement amount detector 15. Further, the reproduction correction signal generator 18 applies a correction signal to the electrostrictive elements 7 and 8 by comparing the traveling mode signal from the preceding mode generating means 21 and the signal from the displacement amount detector 15.

Next, the operation of an example of the apparatus of the present invention described above will be explained.

When the magnetic head 3 tracks a recording track on the magnetic tape 1, the changeover switch 16 is switched to the playback correction signal generator 18 side. As a result, the reproduction correction signal generator 18 uses the displacement amount signals of the electrostrictive elements 7 and 8 from the displacement amount detector 15 and the running mode signal from the running mode generating means 21 to adjust the playback correction signal generator 18 according to the running mode of the magnetic tape 10. A signal is applied to the electrostrictive element 7.8 to bend and deform the electrostrictive element 7.8 so as to cause the magnetic head 6 to track the recording sheet 2. As a result, the magnetic tape 6 tracks the recording track on the magnetic tape 1 in accordance with the running mode. after that,
When the changeover switch 16 is switched as shown in FIG. 1 to record all information on the magnetic tape 1, the electrostrictive element 7.8 has a displacement characteristic with hysteresis, so the magnetic head 6 It is not maintained at the correct position on the tape 1 and is misaligned. This deviation is corrected by a correction signal from the correction signal generator 17 during recording. As a result, the magnetic head 6 has the information displacement detector 1 at the regular position on the magnetic tape 1.
5... Displacement amount detector, 16... Changeover switch, 17
. . . Correction signal generator during recording, 18 . . . Correction signal generator during reproduction, 22 . . . Photodetector.

■　　　1　Figure Non-Z diagram Third mouth

Claims (1)

[Scope of Claims] 1. In a magnetic recording and reproducing device in which a magnetic head is attached to a rotating drum by electromechanical converting means and information is recorded or reproduced on a magnetic tape wound around the outer periphery of the rotating drum, the electromechanical converting means and a control means for outputting a signal to the electromechanical conversion means to correct the hysteresis displacement characteristic of the electromechanical conversion means during recording and reproduction based on the displacement amount of the electromechanical conversion means from the detection means. A magnetic recording and reproducing device characterized by comprising: 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the detection means detects the displacement of the electromechanical conversion means as a change in capacitance. 3. The magnetic recording and reproducing apparatus according to claim 1, wherein the detection means detects the displacement of the electromechanical conversion means as a change in the amount of light. 4. The magnetic recording and reproducing apparatus according to any one of claims 1 to 3, wherein the electromechanical conversion means is an electrostrictive element.