JPH01292678A - Recording/reproducing device - Google Patents

Abstract

PURPOSE:To cancel the back lash of the motion transmission system of a head shifting device, and to position a head adequately by controlling the head shifting device according to the input of a prescribed signal. CONSTITUTION:When a switch input signal such as a power switch 5, a release button 6 is supplied to a control device 10, the control device 10 performs the back lash cancellation of the motion transmission system of the head shifting device 9 by shifting once a write/read head 2 by the head shifting device 9 to a reverse direction by prescribed distance and after that, returning it to a forward direction by the prescribed distance. As the result, the dislocation of the head 2 is corrected, and the head 2 can be positioned at an adequate position.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention Backlash occurs in the head transport mechanism when vibrations, shocks, etc. are applied to the recording/reproducing apparatus. Backlash also occurs when the head is transferred in the opposite direction. Therefore, when the power switch is turned on and the device is activated, when the disk motor starts rotating due to the first depression of the two-stroke shutter release button in a still video camera, and when the head Backlash cancellation processing is performed each time the data is transferred in the reverse direction.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head transport device that transports a write/read head to an arbitrary track of a rotating recording medium for recording/recording.
The present invention relates to a recording/playback device for playback. An example of a recording/reproducing device is a magnetic recording/reproducing device that writes signals on a magnetic disk/reads recorded signals from a magnetic disk, but the present invention also relates to a device that records/reproduces signals optically or magneto-optically. It includes. Furthermore, the term "recording/playback device" is a concept that includes all devices that perform only recording, devices that perform only playback, and devices that have both recording and playback functions.

Conventional technology and its problems A still video signal representing a photographed subject image is recorded on a magnetic recording medium rotated by a magnetic head.
The explanation will be given by taking a video camera or a still video signal reproducing device as an example. A still video camera can record, for example, 50 frames of still images (in the case of field recording), and still video signals are generally recorded sequentially from the outer track to the inner track (outer track). (The direction from the side to the inner circumference is the forward direction.)
. There are cases where the camera is left unattended, with the camera's power switch being turned off and the camera being left unrecorded, with half of the tracks being recorded during shooting, and the remaining tracks remaining unrecorded. If the power switch is turned on again without replacing the magnetic recording medium,
Recording starts from the track where the magnetic head is located.

If the power switch of the camera is turned off and the magnetic recording medium is still loaded in the camera, if the camera is subjected to vibrations or shocks due to carrying the camera, etc., the magnetic head will return to its original and proper stopping position. (track center position). If recording is performed by a magnetic head located at a deviated position, the recording position will also deviate from the proper I/rack position, resulting in an undesirable situation.

In magnetic recording/reproducing devices such as still video cameras, a magnetic head is mounted on a head carriage that is moved in the direction of the magnetic recording medium. The head carriage is constructed so that its vibrations are guided by a guide shaft or the like, and is always biased in one direction by a spring or the like, so that the head can be properly moved in the forward direction. However, backlash occurs when the magnetic head is moved in the opposite direction.

Furthermore, it is difficult to eliminate backlash in a mechanism that converts the rotation of the magnetic head transport drive motor into linear motion of the head carriage.

The position of the magnetic head may shift due to vibration, impact, etc.
It is believed that this is caused by backlash occurring in the rotational/linear motion conversion mechanism described above.

On the other hand, as mentioned above, video signals are recorded sequentially from the outer tracks to the inner tracks, but skip
When recording on a track left unrecorded in a mode (recording is continued while leaving one or more tracks unrecorded), the magnetic head may be moved in the opposite direction. In addition, in a reproducing device, the magnetic head must be positioned on a designated track, so the magnetic head is sequentially moved in the rain direction. According to the above-described head transfer device, it is not possible to prevent backlash from occurring when the magnetic head is transferred in the opposite direction.

These problems are not limited to magnetic recording/reproducing devices, but also optical,
This also applies to devices that perform magneto-optical recording/reproduction.

SUMMARY OF THE INVENTION OBJECTS OF THE INVENTION An object of the present invention is to provide a recording/reproducing apparatus capable of canceling backlash in a motion transmission system of a head transport device.

Structure of the Invention 1 Operation and Effect The recording/reproducing device according to the first invention has a head that transports a write/read head in the radial direction of a rotating recording medium and has a forward direction that prevents the occurrence of backlash. By detecting the input of a transfer device and a predetermined signal, the write/read head is transferred a predetermined distance in the reverse direction before either one of writing a recording signal and reading a recording signal is performed. The present invention is characterized by comprising a control means for controlling the head transport device to transport the write/read head by the predetermined distance in the forward direction.

According to the first invention, when a predetermined signal is input (for example, in the case of a still video camera, when the power switch is turned on or when the shutter release button is pressed down), the head Backlash in the motion transmission system of the head transport device is canceled by once transporting the write/read head a predetermined distance in the reverse direction by the transport device, and then returning it a predetermined distance in the forward direction.

This applies vibrations, shocks, etc. to the recording/reproducing device, and even if the write/read head is slightly deviated from its original proper position due to backlash in the motion transmission system of the head transport device, the write/read head may When writing/reading with a read head, the above backlash
Cancellation can correct the deviation and position the write/read head to its proper original position.

A recording/reproducing device according to a second aspect of the present invention includes a head transporting device that transports a writing/reading head in the radial direction of a rotating recording medium and has a forward direction in which backlash is prevented from occurring, and a writing/reading head. When a command to move the head in a backward direction is given, the write/read head is moved in the reverse direction a distance corresponding to the commanded movement distance plus a predetermined distance for backlash cancellation.

Next, the apparatus further comprises a control means for controlling the head transport device to transport the write/read head by the predetermined distance in the forward direction.

As described above, when the write/read head is transferred in the reverse direction, backlash always occurs in the motion transmission system of the head transfer device. Since the head is moved in the opposite direction by a distance including a predetermined distance for cancellation, and then returned to the forward direction by the predetermined distance, backlash is removed and the head is moved in the opposite direction.

An embodiment in which the present invention is applied to a still video camera having a playback function will be described in detail below, but the present invention is also applicable to a recording device that can only record and a playback device that can only playback.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a block diagram showing the electrical configuration of a still video camera with a playback function.

The operation of each part of the still video camera and the overall operation are supervised by a control device 10. This control device 1
0 is a central processing unit, preferably a microprocessor (
It consists of a CPU (hereinafter referred to as a CPU), a memory that stores its programs and necessary data, and interfaces with each peripheral element circuit, device, etc.

The control bag ff1lO has a power switch5. Switch input signals such as the shutter release button 6 are input. The shutter release button 6 is of a two-stage stroke type, and the first stage of depression turns on the switch S1, and the second stage of depression turns on the switch S2. When the switch S1 is turned on, a disk motor 7, which will be described later, is driven.

Thereafter, when the switch S2 is turned on, photographing and recording are performed.

A magnetic disk 1 on which still video signals are recorded or played back is housed in a disk pack (path shown), and when this magnetic disk 1 is loaded into the camera body, the disk motor drives the magnetic disk 1 at its center. It is attached to the spindle of 7. A magnetic recording/reproducing head 2 (two magnetic heads are provided in a device capable of frame recording) is movable in the radial direction of the magnetic disk 1 so as to be in contact with the magnetic recording surface of the magnetic disk 1 mounted thereon. It is placed in a perfect condition. In addition, a phase detector detects the magnetic flux of the chucking permanent magnet leaking from the magnetic body (path shown) provided in the core of the magnetic disk 1 and generates one pulse PG for each rotation of the magnetic disk 1. 3 is provided close to the core of the magnetic disk 1.

A plurality of (for example, 50) tracks are provided concentrically on the magnetic disk 1. Guard bands are provided between adjacent tracks, e.g.

Track width is 60μm, guard band width is 40μm
m, the track pitch is 100 μm.

The 50 tracks of the magnetic disk 1 are numbered in order from the outer circumferential side to the inner circumferential side, track numbers 1 to 50. The home position HP is located outside the track No. 1, and the end position E is located inside the track No. 50.
P is located.

The disk motor 7 is feedback-controlled by the servo control circuit 8 so as to rotate at a constant rotation speed, for example, 3.60 Or, p, m. Servo control circuit 8
Again. The motor 7 is started and stopped according to commands from the control device 10. Detection pulse PG from phase detector 3
is input to the control device 10. In this embodiment, the magnetic disk 1 is 3. [Since it rotates at a constant speed of 100 r, p, m, the magnetic head 2 records or reproduces one track of still video signals, that is, one field of FM modulated video signals, every 1/60 second of one revolution. become.

The magnetic head 2 is supported movably in the radial direction of the magnetic disk 1 by a transfer drive control device 9, and is controlled to be transferred in the same direction. Transferring the magnetic head 2 from the outer circumferential side to the inner circumferential side of the magnetic disk 1 by the transfer drive control device 9 is called forward transfer, and the transfer in the opposite direction is called reverse transfer.

The control device IO gives instructions to the device 9 regarding the direction and amount of movement of the magnetic head 3. Device 9 is a step
The stepping motor includes a motor, and when a predetermined number of drive pulses are applied, the step motor rotates a predetermined angle, and the magnetic head 2 is moved by a distance corresponding to the number of pulses. For example, by applying one pulse to a step motor, the magnetic head 2 is moved by 10 μm. An example of a specific configuration of this transfer drive control device 9 will be described later.

Since video signals are recorded or reproduced while the magnetic disk 1 is being rotated, a regulating plate 4 is provided to maintain good contact between the magnetic head 2 and the magnetic disk 1 at all times.

An imaging optical system 20 provided in the still video camera includes an imaging lens system 21 for forming a subject image. It is composed of an aperture 22 and an optical shutter 28. The diaphragm 22 is controlled by the control device IO based on the light reception signal level of the light receiving element (path shown) arranged in the optical path.
Optical shutter 23 is controlled by control device 10 in response to input from switch S2, which is turned on by second-stage depression of shutter release button 6.

A solid-state electronic imaging device 24 consisting of a two-dimensional imaging cell array, such as a COD, is disposed at the focal plane of the optical system 20. The video data accumulated in this imaging device 24 is serially converted to still images in synchronization with vertical and horizontal synchronization signals.
The video signal is read out, and its luminance signal component and chroma signal component are FM-modulated in the recording signal processing circuit 25, and these modulated signals are combined and applied to the magnetic head 2 via the switching and amplifying circuit 26. It will be done. The switching/amplifying circuit 2B switches and amplifies the recording signal given to the magnetic head 2 and the read signal by the magnetic head 2 according to the recording mode and the reproduction mode.

A read signal from a predetermined track of the magnetic disk 1 by the magnetic head 2 is applied to an envelope detection circuit 27 via a switching and amplifying circuit 26 or to a reproduction signal processing circuit 28 .

The envelope detection circuit 27 detects the envelope of the read signal, converts it into a digital signal, and sends it to the control device IO.
give to The control device 10 uses the input envelope detection signal to perform track search processing and peak position detection processing. Track search processing is performed when a new magnetic disk 1 is loaded or when the magnetic disk 1 is replaced, and by moving the magnetic head 2 across all tracks of the magnetic disk 1, Recorded tracks and unrecorded tracks are discriminated and stored as a track map. Generally, in recording mode, still pictures taken with reference to this track map are
A video signal is recorded on the outermost unrecorded track. The peak position detection process is performed in the reproduction mode, and involves detecting the peak position of the envelope of the recording signal in the designated track to be reproduced, and positioning the center of the magnetic head 2 there.

In addition to controlling the rotation of the magnetic disk 1 and recording and reproducing still and video signals, the control device 10 also controls the reading of various switches, the operation of the camera based on the reading results, and the transfer control of the magnetic head 2. Let's do it.

Various switches include a power control switch 11. A load end detector detects that the openable and closable packet containing the disk pack containing the magnetic disk 1 is closed.
Switch 12. Pack switch 1 detects that a disk pack is contained within a closed packet
3. There is a home position contest switch (path shown) that detects that the magnetic head 2 is at the home position HP.

The control device IO performs a key scan routine at regular intervals (for example, 1/60 seconds), and in this key scan routine, the control device IO sends a key scan pulse to the above-mentioned switch group, and this pulse The on/off status of the switch is detected depending on whether it has returned.

The control device 10 further includes a forward switch, a reverse switch, and a track number of the magnetic head for specifying a track to be reproduced in the reproduction mode.

Input switches, etc. (collectively indicated by reference numeral 14), recording/reproduction mode selection switches, etc. (paths shown) are provided.

FIG. 2 shows a specific example of a part of the magnetic head transfer drive control device 9. As shown in FIG.

Referring to this figure, a magnetic head transfer drive control device 9 is assembled on a substrate 30. As shown in FIG. A disk motor 7 (not shown in FIG. 2) for rotating a spindle 33 is attached to a mounting member 31 provided approximately in the center of the substrate 30 and projecting slightly upward. disk·
The spindle 33 of the motor 7 is for chucking and rotating the magnetic disk 1 in the disk pack, and protrudes from a circular opening 32 formed in the mounting member 31. Furthermore, two bottles 34 and two bottles 35 are erected on the board 30. The bins 34 are for positioning the disk packs, and the disk packs are positioned by inserting these pins 34 into the positioning holes of the loaded disk packs. The pin 35 is a stopper on the outer peripheral side of the head carriage 40.

A lead screw 50 having a threaded portion 51 formed at one end thereof is horizontally and rotatably provided on the substrate 30-F. Lead screw 50 is rotatably supported at both ends by bearings 56,57.

The bearings 5B and 57 support the circumferential surfaces of both ends of the lead screw 5o by pressing them against the support columns 58a and 57a, respectively, and stoppers are provided on both end surfaces of the lead screw 50 to prevent it from moving in the longitudinal direction. It is being

A worm gear 55 is fixed to the opposite side of the threaded portion 51 of the lead screw 50. The worm gear 55 meshes with a worm 53 fixed to an output shaft 54a of a step motor 52 (indicated by a broken line).

The step motor 52 is fixed to the back side of the board 30, and its output shaft 54 passes loosely through a hole drilled in the board 30 and extends to the front side. The lead screw 50 is rotated by the drive of the step pot motor 52.

The head carriage 40 has an integrally formed sliding part 41.
and a head attachment part 42, which are connected to each other at one end so as to form an L-shape when viewed from above.

A recess 43 is formed in the sliding portion 41 in its longitudinal direction, and the lead screw 50 passes through this recess 43. The spindle side of this recess 43 is open except for the end of the sliding portion 41 to which the head attachment portion 42 is coupled. Of course, all parts of the recess 43 are open on the lower side. The recess 43 has a horizontal surface facing downward and a vertical surface facing inward. Worm gear 55 of sliding part 41
At one end located toward , a portion 43a is formed that slightly protrudes from both surfaces of the four parts.

A needle 44 that engages with the groove of the threaded portion 51 of the lead screw 50 is embedded in the other end of the sliding portion 41, that is, the portion where it joins the head mounting portion 42. This needle 44
crosses the upper part of the recess 43 diagonally. A protruding sliding portion 43b that comes into contact with the threaded portion 51 of the lead screw 50 is provided on the vertical surface of the recess 43. A spring (path shown) causes two parts 43a to be attached to the circumferential surface of one end of the lead screw 50 other than the threaded part 51, and a needle 44 and a protruding sliding part 43b to the threaded part at the other end of the lead screw 50. 51 valleys and peaks, respectively.
Head carriage 40 and lead screw 50 are energized.

A recess is formed near the center of the head mounting portion 42 of the head carriage 40, and a mounting piece 47 that projects upward is provided in this recess. The magnetic head 2 is fixed to a mounting piece 47 via a mounting member 46 .

A stepped portion is provided at the end of the head mounting portion 42 opposite to the connecting portion with the sliding portion 41, and a horizontal surface 48 is formed here. Rods 49 each supported by a pedestal 58 having a predetermined height at both ends pass over the horizontal surface 48 . From below, the head-carriage 40 connects the substrate 30
Alternatively, it is fixed to one side of the carriage 40 in the head and is biased upwardly by a spring (path shown) that is slidable against the other side.

The head carriage 40 rotates in the forward direction (FW) or in the reverse direction (FW) by rotating the lead screw 50 via the worm 53 by the forward or reverse rotation of the step motor 52.
Move to RV). As a result, the head carriage 40
The magnetic head 2 attached to the magnetic head 2 is moved in the forward direction (FW) and the reverse direction (RV).

The head carriage 4 is moved by the above-mentioned spring (not shown).
0 and the lead screw 50 are biased so that they are in contact with each other in a constant relationship, so as long as the magnetic head 2 is transferred in the forward direction (FW), the position of the magnetic head 2 is controlled by the step motor 52. It is precisely determined by the number of pulses applied. However, since it is impossible to bias the engagement between the worm 53 and the worm gear 55 in a fixed direction with a spring or the like, the magnetic head 2 is moved in the opposite direction (
When the vehicle is transferred to an RV, it is inevitable that a slight backlash will occur. Furthermore, due to vibrations, shocks, etc. applied to the still video camera, the meshing position between the worm 22 and the worm gear 23 may shift slightly. The position of the magnetic head 2 may deviate from its original position defined by the number of pulses applied to the step motor 52.

FIG. 3 shows a processing procedure by the control device 10 for removing the positional deviation of the magnetic head 2 caused by the above-mentioned backlash (backlash cancellation) and positioning the magnetic head 2 at an appropriate position = 20 -. It is a flowchart which shows.

This process is initiated in various cases. The first is when the power switch 5 is turned on and the switch-on signal is input to the control device 10. Second, the shutter release button 6 is pressed down.

This is when the input signal from the switch S1 is given to the control device 10. In all of these cases, backlash cancellation processing is performed to correct misalignment between the worm 53 and the worm gear 55 due to vibrations or shocks being applied to the still video camera. At this time, N='O is set in step 81.

The third is the edit mode (predetermined blank space) of the recording mode.
・When the track number to be recorded is specified in a mode in which signals are recorded on a rack, etc., and it is necessary to move the magnetic head 2 in the opposite direction to position it on the specified track, or in a playback mode. This is a case where the magnetic head 2 must be moved in the opposite direction in order to position it on the designated track to be reproduced. In such a case, N is the number of pulses that should be applied to step motor 22 to move the magnetic head from the current track position to the designated track position.

In the first and second cases, four pulses are applied to reverse the stepper motor 52 (step 81). As a result, the magnetic head 2 is moved a predetermined distance in the opposite direction. Subsequently, four pulses are applied to rotate the step motor 52 in the forward direction, thereby moving the magnetic head 2 forward a predetermined distance and returning to its original position (step 82).

The head carriage is once moved in the opposite direction, and then transferred again in the forward direction the same distance to return the magnetic head to its original position.

In this way, the misalignment between the worm 53 and the worm gear 55 is corrected. In other words, the magnetic head 2 is based on the vibrations and shocks given to the still video camera.
The slight positional deviation has been corrected.

In the third case, (N+4) pulses are first applied to the step motor 52 for backward movement (step 81).
), followed by four pulses to the stepper motor 52 for forward transport (step 82).

As a result, the magnetic head 2 is moved in the opposite direction by a distance corresponding to N pulses, and the backlash caused by the movement in the reverse direction is eliminated.

In the example above, 4 pulses are transferred in the reverse and forward directions to cancel backlash, but the transfer is not limited to 4 pulses, and any distance in the reverse and forward directions may be performed. Needless to say.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the electrical configuration of a still video camera with playback mode, and Figure 2 is a block diagram showing the electrical configuration of a still video camera with playback mode.
FIG. 3 is a plan view showing an example of a specific configuration of a magnetic head transfer drive control device for a camera, and a flowchart showing a processing procedure for backlash cancellation. 1...Magnetic disk. 2...Magnetic head. 5...Power switch. 6...Shutter release button. 9... Transfer drive control device. 40...Head carriage. 44... Needle. 50...Lead screw. 52...Step motor. 53... Warm. 55... Worm gear. that's all

Claims (2)

[Claims] (1) A head transport device that transports a write/read head in the radial direction of a rotating recording medium and has a forward direction that prevents the occurrence of backlash, and a recording signal that is detected by detecting input of a predetermined signal. The writing/reading head is transported a predetermined distance in the reverse direction, and then the writing/reading head is transported in the forward direction by the predetermined distance before either one of writing the recording signal and reading the recording signal is performed. A recording/reproducing device comprising: control means for controlling the head transport device. (2) A head transport device that transports the write/read head in the radial direction of the rotating recording medium and is provided with a forward direction that prevents the occurrence of backlash, and a reverse direction transport command for the write/read head. , the write/read head is transported a distance in the reverse direction corresponding to the commanded transport distance plus a predetermined distance for backlash cancellation, and then the write/read head is transported the predetermined distance in the forward direction. A recording/reproducing device comprising: control means for controlling the head transfer device so as to transfer the head to the head.