JPS63249969A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain good head touch at all times by controlling a pad moving means based on the output of an envelope detection means. CONSTITUTION:The position of a pad 11 is controlled via a stepping motor 23 based on the envelope of the signal reproduced via a magnetic head 14. In the period while the relative speed of a magnetic recording medium 12 and the magnetic head 14 is low, the pad 11 is separated from the magnetic recording medium 12 to reduce the pressure welding force between the former and latter. Namely the pad position is controlled so that the envelope of the reproducing signal of the magnetic head 14 become larger and the positional control of the pad 11 is effected whenever the track position is changed, hence the head touch varies by the position on the radius of the magnetic recording medium 12 and there is no problem of deteriorating the recording and reproducing characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing device, and particularly to a magnetic recording and reproducing device that performs magnetic recording and reproducing using a magnetic head on a rotationally driven magnetic recording medium.

[Prior Art] Magnetic recording and reproducing devices are widely used for recording and reproducing text, image, and audio data.

BACKGROUND ART In devices that perform recording and reproduction by bringing a magnetic head into contact with a magnetic tape or a magnetic disk, there is a problem of wear of the magnetic recording medium itself, the magnetic head, pressure pads, guides, and the like.

[Problems to be Solved by the Invention] For example, in a methyl video device for recording and reproducing still image data, a structure as shown in FIG. 5 is known. In the figure, reference numeral 14 denotes a magnetic head, which is disposed facing the U-shaped positioning pads 11, and is positioned by these, and the magnetic recording medium 12 passes therethrough.

Usually, in this type of device, there is a magnetic head 14 and a magnetic recording medium 1.
2 is about 6 m/s, and at this speed, an air layer (air film) is generated between the magnetic head 14 and the magnetic recording medium 12 and between the magnetic recording medium 12 and the pad 11, and the magnetic recording The medium 12, pad 11, and magnetic head 14 are in a non-contact state.

However, when the rotation of the magnetic recording medium 12 starts and stops, the relative speed decreases, and an air layer is not formed between the magnetic recording medium 12, the magnetic head 14, and the pad 11, resulting in a contact state. In particular, at the start, a strong frictional force acts between the magnetic recording medium 12, the magnetic head 14, and the pad 11.

If the magnetic recording medium 12 was coated with a magnetic material, there would not be much of a problem even under such operating conditions, but thin film media such as Co-Ni and Co-Cr have poor wear resistance. becomes a problem.

To avoid this problem, the position of the magnetic head 14 is set back from a predetermined recording/reproducing position before the magnetic recording medium 12 starts rotating at a high speed, and when the magnetic recording medium starts rotating at a predetermined high speed, the magnetic head 14 14 to the recording/reproducing position.

However, in devices such as still video, where head touch is extremely important, it is not desirable to move the head, and when doing so, extremely high precision is required, resulting in high costs. be.

In addition, in the positioning method using pads as described above,
When a flexible magnetic recording medium is used, there is a problem in that the state of head touch changes greatly between the inner circumference and the outer circumference of the medium due to changes in its rigidity. Usually, a design or adjustment is made so that a good head touch can be obtained near the center of the radius of the medium, but there is still a problem in that the recording and reproducing characteristics deteriorate at the outer and inner peripheries of the medium.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, a rotationally driven magnetic recording medium is positioned from both sides by a magnetic head and a pad of a predetermined shape, and the magnetic recording medium is In a magnetic recording and reproducing apparatus that performs recording and reproducing, means for detecting an envelope of a signal reproduced from a magnetic recording medium through the magnetic head, and means for moving the pad toward or away from the magnetic recording medium; A configuration is adopted in which means is provided for controlling the pad moving means based on the output of the envelope detecting means.

[Function] According to the above configuration, for example, by controlling the detected envelope to be as large as possible, the influence of changes in head touch depending on the position of the magnetic head on the radius of the magnetic recording medium can be suppressed. It can be eliminated.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 shows the structure of the main parts of a still video apparatus employing the present invention. In the figure, reference numerals 11, 12, and 14 indicate a pad, a magnetic recording medium, and a magnetic head, respectively, which are constructed in the same manner as in the conventional example.

The position of the magnetic head 14 is not moved, but is fixed at the most suitable position for recording and reproducing.

In this embodiment, sliders 21 are provided before and after the pad 11 with respect to the direction in which the magnetic recording medium 12 travels.
Allows you to adjust the position relative to the The position of the pad 11 can be moved toward or away from the magnetic recording medium 12 on the opposite side of the magnetic head 14.

That is, the pad 11 has a pole screw 22 at the center of its upper part, and a gear portion 22a thereof meshes with a pinion gear 23a fixed to a drive shaft of a stepping motor 23. Therefore, by rotating the stepping motor 23 by a predetermined amount, the position of the pad 11 with respect to the magnetic recording medium 12 can be controlled as desired. The pole screw 22 is slidably supported by a shaft holder 24.

The position of pad 11 is controlled by the configuration shown in FIG.

In FIG. 2, reference numeral 41 denotes a recording/reproducing control unit, which is an integrated circuit using a microprocessor for magnetic disk control or an amplifier for recording/reproducing signals in order to control the entire recording and reproducing operation for the magnetic recording medium 12. Consists of etc.

Recording and reproduction of information is performed by a magnetic head 14. Data input/output to/from the magnetic recording medium 12 is exchanged with an external device via an input/output control section 42 using a predetermined method.

Note that the rotational drive control system for the magnetic recording medium 12 is omitted from illustration as it has exactly the same configuration as the conventional one.

The input/output signals of the magnetic head 14 are connected to the recording/reproducing control section 41, and at the same time, the envelope of the signal output by the magnetic head 14 is input to the envelope measuring section 44, and the envelope value detected by the envelope measuring section 44 is input to the envelope measuring section 44. is input to the recording/reproducing control section 41. Data input to the recording/reproducing control section 41 is performed by converting it into a digital value.

Further, the rotation of the stepping motor 23 for controlling the position of the pad 11 is controlled by a recording/reproducing control section 41. In this embodiment, the position of the pad 11 is controlled via the stepping motor 23 based on the envelope of the signal reproduced via the magnetic head 14. In addition, during a period when the relative speed between the magnetic recording medium 12 and the magnetic head 14 is low, the pad 11 is separated from the magnetic recording medium 12 so that the magnetic recording medium 14
2 and the magnetic head 14 to prevent abrasion of the magnetic recording medium 12.

The control procedure of the recording/reproduction control section 41 is executed by RO as a program.
Stored in M43. FIG. 3 and FIG. 4 show an example of a pad control procedure of the recording/reproduction control section 41 stored in the ROM 43. Hereinafter, the pad control procedure will be explained with reference to FIGS. 3 and 4, and it is assumed that the flows labeled with the same numbers in FIGS. 3 and 4 are continuous at that position.

First, when the apparatus is reset in a state where the magnetic recording medium 12 is not being rotationally driven, in step s1, it is detected whether the pad 11 is separated from the magnetic recording medium 12, and if it is not, stepping is performed. The motor 23 is rotated by a predetermined amount in a predetermined direction to raise the pad 11 and separate it from the magnetic recording medium 12 .

Next, in step S2, rotational driving of the magnetic recording medium 12 is started. The rotational speed of the magnetic recording medium 12 is conventionally measured by detecting index holes in the magnetic recording medium 12, and control is performed based on the measured value so that a constant rotational speed is obtained.

However, in this embodiment, during acceleration, it is determined in step s3 whether the rotational speed of the magnetic recording medium 12 is sufficiently high. The threshold value for this determination is such that the relative speed between the magnetic recording medium 12 and the magnetic head 14 causes an air layer, that is, the pad 11. The speed is set to such an extent that the magnetic recording medium 12 will not be worn out even if the magnetic head 14 performs positioning.

Next, in step S4, a standard operating state is set.

That is, the processing includes moving the magnetic head 14 to a predetermined track position and rotating the stepping motor 23 to move the pad 11 to an initial control position.

Subsequently, pad position control based on envelope detection is started from step S5. In the following, the detection envelope value is indicated by the symbol J. Controls from step 85 onwards are performed in parallel with normal recording and reproducing operations or by time-sharing processing.

In step S5, the envelope value reproduced from the magnetic head 14 is detected via the envelope measuring section 44.

The detected value is input to the recording/reproducing control section 41 after being subjected to processing such as digital conversion by the envelope measuring section 44. Here, the initial detection value is stored as JO in an internal memory or the like. In the following, envelope detection is performed at a constant rotation angle position of the magnetic recording medium 12. It is preferable to record the most suitable position for each track in advance.

Next, in step S6, the stepping motor 23 is rotated by one step in a direction to bring the pad 11 closer to the magnetic recording medium 12, and the envelope value is detected again and set as Jl.

In step S7 of FIG. 4, the detected envelope value J
Compare O1J1. If JO is larger, the process moves to step S8, and if Jl is larger, the process moves to step S13.

The transition to step S8 occurs when there is a possibility that the pad 11 has been brought too close to the magnetic recording medium 12.
Controls such as steps S8 to S12 are performed.

In step S8, the stepping motor 23 is rotated by one step in a direction to separate the pad 11, and envelope detection is performed. The detected value is assumed to be J-1.

In step S9, the detected envelope data, JOl
Compare Jl and J-1. Here J-1<JO>Jl
, or J-1>J O>J 1 is determined.

If J-1<JO>Jl, the process moves to step SIO; otherwise, the process moves to step Sll.

In step SIO, pad ll is set to envelope detection value J
Fix it at a position where O is obtained. Thereby, the pad 11 can be positioned at the optimum position where the largest reproduction signal can be obtained.

In step Sll, the largest detected value J-1 is set to J
O, and replace JO with Jl.

In step S12, the pad 11 is moved one step away from the magnetic recording medium 12, the envelope is detected again, the detected value is set to J-1, and the envelope is detected in step S12.
The process loops to step S9 until the condition O is satisfied.

On the other hand, the process moves to step S13 when there is a possibility that the amount of approach of the pad 11 is insufficient, and the following control is performed.

In step S13, the pad 11 is further moved one step closer to perform envelope detection, and its value is set as J2.

In step S14, the ratio of JO5J1 and J2.

Make a comparison. The conditions are J O < J 1 < J 2, or J
O<J 1>J 2.

In the case of J O<J 1>J 2, the process moves to step 316 and the pad 11 is fixed at a position where the largest envelope data J1 can be obtained.

If not, proceed to step S15, replace data J1 with JO, replace data J2 with Jl, and step S15.
15 and continues the loop until step S14 is satisfied.

Next, in step S17, it is determined whether the target processing such as the recording/reproducing operation has been completed. If the process has ended, the process proceeds to step S20, and if not, the process proceeds to step S18, where it is determined whether a track change should be made.

If a track change, that is, a process of moving the magnetic head 14 on the radius of the magnetic recording medium 12, is not necessary, the process returns to step S17, but if necessary, the process proceeds to step S19, and the magnetic head 14 is moved in a similar manner to a known method. It is fed by a predetermined amount via the spacing seek mechanism and moved to the desired track position.

At this time, the position of the magnetic head 14 on the radius of the magnetic recording medium 12 changes, so in order to obtain a constant flat touch, the process moves to step S4 in FIG. 3 and the position of the pad 11 is adjusted again.

In step S20, before stopping the rotation of the magnetic recording medium 12 in step S21, the pad 11 is completely rotated to the magnetic recording medium 12 by the stepping motor 23.
Raise it to a position where it is away from the

According to the above configuration, the envelope of the reproduction signal of the magnetic head 14 is the largest? pad 1
By controlling the position of 1, it is possible to perform recording and reproducing operations while keeping the recording and reproducing efficiency as good as possible. In this embodiment, since the position of the pad 11 is controlled each time the track position is changed, there is the problem that the head touch changes depending on the position on the radius of the magnetic recording medium 12, resulting in deterioration of recording and reproducing characteristics. There is no.

In addition, since the pad 11 is separated from the magnetic recording medium 12 when starting and stopping the magnetic recording device 2, the pressure contact force between the magnetic recording and reproducing device 2 and the magnetic head 14 is reduced during the period when there is no protection from the air layer. The magnetic recording medium 12 can be reliably protected.

The driving source for moving the pad 11 is not limited to the above-mentioned stepping motor, but may also include a voice coil,
A plunger, a plate spring, a piezoelectric element, and other desired driving means and biasing means can be used in combination.

Alternatively, the pad 11 may be operated directly using a plunger or the like without using a slider or the like.

Furthermore, although the position of the pad 11 is controlled in an open loop in the control described in item 2, the position of the pad 11 may be detected using an encoder or the like to perform closed loop control.

[Effects of the Invention] As is clear from the above, according to the present invention, a magnetic recording medium that is rotationally driven is positioned from both sides by a magnetic head and a pad of a predetermined shape, and magnetic recording and reproducing is performed using the magnetic head. The apparatus includes means for detecting an envelope of a signal reproduced from a magnetic recording medium through the magnetic head, a means for moving the pad toward or away from the magnetic recording medium, and an output of the envelope detecting means. Since the structure includes means for controlling the pad moving means based on the above-described structure, it is possible to always obtain a good head touch, and stable magnetic recording is possible regardless of the position of the magnetic head on the radius of the magnetic recording medium. It has the erosive effect of being able to perform regeneration.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the structure and operation of the main parts of a still video device employing the present invention, FIG. 2 is a block diagram showing the control system of the device in FIG. 1, and FIGS. This figure is a flowchart showing the control procedure of the recording/reproducing control section of FIG. 2, and FIG. 5 is an explanatory diagram showing the conventional structure. 11... Pad 12... Magnetic recording medium 1
Day 14...Magnetic head 21...Slider 23...
- Motor 41... Recording/playback control section 44...
Envelope measurement section Figure 1 Night 1 duty and comparison power Figure 5? 1 frame 10'f''+! Reflow 4 and - diagram Figure 3

Claims (1)

[Scope of Claims] 1) In a magnetic recording and reproducing apparatus in which a rotationally driven magnetic recording medium is positioned from both sides by a magnetic head and a pad of a predetermined shape, and the magnetic head performs magnetic recording and reproduction, the magnetic recording medium is moved from the magnetic recording medium to the magnetic head. means for detecting an envelope of a signal reproduced through the magnetic recording medium; means for moving the pad toward or away from the magnetic recording medium; and means for controlling the pad moving means based on the output of the envelope detecting means. A magnetic recording/reproducing device characterized in that: 2) When the rotation start period or end period of the magnetic recording medium or the relative speed between the magnetic head and the magnetic recording medium is below a predetermined value, the pad is separated from the magnetic recording medium using the pad moving means, and the magnetic head Claim 1 characterized in that the pressure contact force between the magnetic recording medium and the magnetic recording medium is reduced.
The magnetic recording and reproducing device described in 2.