JPS5916330B2 - Head evacuation device in a recording/reproducing device using a rotating recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a head evacuation device in a recording/reproducing apparatus using a rotating recording medium, and in particular to a head retracting device for a recording/reproducing apparatus using a rotating recording medium such as a magnetic sheet. Rotate at high speed in synchronization with i0 signal,
In a device that records and reproduces a video signal, which is an information signal, in units of field or frame signals by attaching a magnetic head to a rotating recording medium and moving it in the radial direction, the head performs recording mode when changing from a stop mode to a recording/reproducing mode.
5. Recording and reproduction using a rotating recording medium configured to move the head to a predetermined evacuation position outside the recording track area when the head is located within the track area, and to prevent damage to the recording medium and the head when starting the recording medium. The object of the present invention is to provide a head retracting device in an apparatus.

In general, a magnetic head is attached to a rotating magnetic body such as a magnetic sheet, a magnetic disk, or a magnetic drum, and is moved intermittently, and information signals such as television video signals are transmitted by using the stop period of the magnetic head. In a device that continuously records and reproduces information on a large number of concentric tracks in i5 yield or frame units, a magnetic head is in contact with a rotating magnetic body under a constant pressure.

However, during recording or reproducing when the rotating magnetic body is rotating at a constant speed (for example, 60 revolutions per second), the magnetic head has a small gap (0.050 m) between the magnetic body and the magnetic head due to the airflow generated in the area adjacent to the rotating body. .1 micron), or is in contact with the rotating magnetic body with an extremely small contact force. Therefore, when the apparatus is set in the recording/reproducing mode, the magnetic body is rarely damaged by the magnetic head, and the life of the rotating magnetic body is not adversely affected. However, since the rotation speed of the rotating magnetic body is low when starting and braking the rotation, the magnetic head is not given buoyancy and comes into contact with the magnetic body under considerable pressure, causing damage to the magnetic surface of the rotating magnetic body. It was hot.

In particular, when the rotating magnetic body starts rotating from a stationary state, the magnetic head slightly vibrates due to the friction generated between the magnetic head and the surface of the magnetic body, resulting in a significant degree of damage. Therefore, the following method was proposed as a means to solve the above problems.

A method in which the magnetic head is separated from the surface of the rotating magnetic material using a mechanism such as a plunger when the rotation of the magnetic material starts.

2. A method in which the magnetic head is linked with a governor mechanism that controls the rotation of the rotating magnetic body, and the head is attached to the rotating magnetic body only when the rotating magnetic body is rotating at a predetermined number of rotations.

In method 1, since the magnetic head is moved in the vertical direction, tracking accuracy (generally about ±10 μ for a track pitch of about 100 to 200 μ) cannot be obtained, and a mechanism for moving the magnetic head up and down is required. This has the disadvantage that the structure of the magnetic head transfer device is complicated.

In addition, the second method has the disadvantage that the structure is complicated and the manner in which the head is attached to the rotating magnetic body is unstable. Therefore, as a means to solve the above problem, there are various mechanisms that mechanically release the attachment of the magnetic head to the rotating magnetic body when the rotating magnetic body starts rotating, but each mechanism is complicated and unreliable. I had the disadvantage of being inferior to my gender.

In addition, in order to eliminate the above-mentioned drawbacks, the present applicant previously filed a patent application
According to No. 8-27717, when the magnetic body rotates at a rotation speed lower than a predetermined rotation speed, that is, when the device is converted from the recording/reproducing mode to the stop mode, and when the device is converted from the stop mode to the recording/reproducing mode, We have proposed a device that retracts the magnetic head outside a predetermined recording/reproducing area.

In addition, as a recording/reproducing device using a rotating recording medium, a sheet storage housing (pack assembly) containing a magnetic sheet is attached to the device, and the magnetic sheet is connected to a disk motor and rotated at high speed to perform recording/reproducing operations. There are several recording and reproducing devices. In this device, since the head is exposed when the device is not in use and the pack assembly is not attached, the head may be moved from a predetermined position due to the operator's carelessness. In this state, the magnetic surface of the sheet may be damaged by the head at the beginning of rotation of the sheet when the pack assembly is mounted and the apparatus is changed to the recording/reproducing mode. In addition, in this type of device, when converting the device from recording/playback mode to stop mode, the main (AC)
lOO) There are cases where an operation is performed to directly open the power supply circuit. For this reason, the head evacuation device applied to the former recording/reproducing apparatus cannot be directly applied to the latter sheet pack type recording/reproducing apparatus. The present invention is capable of transferring the head to the standby position when the device in the recording/reproducing mode is converted to the stop mode by opening the disk motor drive switch, and when the power switch is opened and the main power supply circuit is opened to change the device to the stop mode. The object of the present invention is to provide a device that automatically moves the head to a predetermined evacuation position when the head is not at the predetermined evacuation position when the apparatus is converted from the stop mode to the recording/playback mode. be.
An actual example of the device of the present invention will be explained below with reference to the drawings.

First, the mechanical configuration will be explained with reference to FIGS. 1 and 2. The seat pack assembly 1 has a magnetic sheet 2 inside.
It is rotatably stored and attached to a predetermined position on the device. In this embodiment, the magnetic sheet 2 has a central holding portion 3 fixed to a motor shaft of a disk motor 5 attached to a chassis 4, and is rotated at high speed by the motor 5.
The motor 5 is controlled by a pulse signal transmitted every time the tone wheel pulse pickup head 6 detects the permanent magnet 7, and is rotated at a high speed of 3600 rpm. The head transfer mechanism will now be described with reference to FIGS. 2 and 3.

The head transfer pulse motor 8 is mounted on the head transfer mechanism mounting base 9.
It is fixed to the upper bracket 10 and rotated intermittently in phase synchronization with the pulse signal from the head 6. motor 8
As a result of the rotation, the flexible metal belt 12, which has one end fixed to the drive wheel 11 on the motor shaft, is guided by the guide member 13 and wound around or unwound around the drive wheel 11. The video head assembly 14 is fitted into the seat pack assembly 1 and fixed to a head mount 16 which is slidably fitted into a guide member 15 disposed in the radial direction of the seat 2. Further, since the other end of the belt 12 is attached to the head assembly 14, the head assembly 14 is brought into contact with the magnetic surface of the sheet 2 by the operation of the pulse motor 8 and is intermittently moved in the radial direction thereof. A plurality of tracks are formed concentrically on the sheet 2 as will be described later. Note that when the disk motor 5 is rotating at a predetermined speed, the magnetic sheet 2 is attached to the annular member 17 attached to its outer circumference.
It is rotated at high speed in a horizontally stretched manner due to the centrifugal force generated. 18 is a proximity switch for detecting the reference position, and the head assembly 1 is guided and transferred by the guide member 13.
When the magnetic sheet 2 is moved further from the upward feed start and reversal position 5 and is transferred out of the recording track area, the permanent magnet piece 19 provided on the head mount 16 approaches to open and close the magnetic sheet 2. In the device of this embodiment, it is installed at a position corresponding to the head retraction position 11.

Further, the limit switch 20 on the inner diameter side is in the seat 2 upper head inversion position 1. Furthermore, if the control operation of the pulse motor 8 becomes abnormal and the head assembly 14 moves in the direction of the inner circumference of the sheet 2 beyond the predetermined transfer range, It is opened and closed by being engaged with a protrusion 21 protruding from the head mounting base 16. Further, the outer limit switch 22 is disposed at a position outside the inverted position on the outermost circumferential side of the upper head 14 of the seat 2.
When the limit switch 20 is abnormally moved toward the outer circumference, it is closed in the same manner as the limit switch 20 described above. Further, the structure of the head assembly 14 will be explained in conjunction with FIGS. 4A and 4B.

Reference numeral 30 denotes a head holding casing, which is attached to the head mount 16, and an elastic damper membrane 31 having excellent damping properties, which is formed by concentrically forming corrugations with an uneven and corrugated cross section, is attached to the upper surface of the casing 30.

Reference numeral 32 designates a head core mounting base 32 on which a video head core 33, advance erasing core 34, and dummy core 35 are arranged at positions geometrically corresponding to the vertices of a virtual triangle, and is mounted on the damper membrane 31. There is.

Therefore, with respect to the magnetic sheet 2, the cores 33, 34 and 3
5 is stably attached using a so-called three-point support structure. The erasing core 34 is similar to the video core 33 in the rotating direction of the magnetic sheet 2.
It is positioned to trace the same track as the track formed by the core 33 and at a position preceding the core 33 . Further, the track width of the erasing core 34 is set to be slightly wider than the recording track width of the video core 33. Also, in the radial direction of the seat 2, the video head core 33 and the dummy core 3
The distance d from 5 is d=3m7! It is said to be L. Further, the video head assembly 14 is moved to a retracting position indicated by 11 on the magnetic sheet 2 during the retracting operation described below.

When the head assembly 14 is moved to the retracted position 11, the video core 33 is moved to the track T in FIG. 5A. 1, and the dummy core 35 is track T. Trace 2.

Here, the track TOl is a track T traced by the dummy core 35 when the video core 33 is tracing the innermost track GtO or Btn of the recording area. It is set toward the inner circumference from O. Further, the video head assembly 14 is alternately moved by the pulse motor 8 on the outward path and the backward path, and the video core 33 is moved on the sheet 2 on the outgoing path tracks G, O, Gtl, Gl2, . . . , Gt.
(n-1), Gtn and return track BtOlBtl
lBt2!゜゜"゜゜?Bt(n-1)Jtn is formed into a comb shape as shown in FIG. 5A.

Here, the pulse motor 8 is normally rotated by two steps, and is rotated by one step when the head transport direction is reversed. Further, the video tracks on the magnetic sheet 2 are formed as shown in an enlarged view in FIG. 5B, and the track pitch T between adjacent tracks is T, = 150μ. is set to . Note that when the head assembly 14 reaches the innermost position 10 on the seat, the video core 33 moves to the innermost track Gt.
In the mode in which O or Bln is being traced, the head assembly 14 moves further toward the inner circumferential direction of the seat by 2 track pitches or 15 steps to reach the retracted position 11. That is,
The head assembly 14 is located at the innermost position 1. 150μm×2
Position 1 moved further inward by ×15=4.5mm
, is considered to be the evacuation mode. Therefore, head assembly 1
4 is moved to the retracted position 11, the video core 33 is moved to the track T on the seat. Track T located further inward than O. Trace l. Therefore, when the rotation of the magnetic sheet 2 is stopped, the head assembly 14 has been moved to the retracted position in advance as will be described later, and a track T formed by a dummy core 35 is placed on the sheet 2.

2, a video core 33, and an erasing core 34.

, will be formed and the magnetic surface on the sheet 2 will be damaged in each track portion located in the unused area. Furthermore, when the device in the stop mode in which the head assembly 14 is in the above-mentioned retracted position is converted to the recording/reproducing mode, the head coarse body 14 is moved in the outer circumferential direction and the dummy core 3 is moved.
Truck T with 5 damaged. When reaching the position where 1 is to be traced, sheet 2 of the video core 33 and erase core 34 is
The manner in which it is attached also becomes unstable. However, at this time, since the cores 33 and 34 both trace portions located further inward than the innermost recording tracks GlO and Bln, damage to the magnetic surfaces in the recording/reproducing area is prevented. Next, we will discuss one embodiment of the block system diagram of the device of the present invention.
This will be schematically explained with reference to the drawings.

In the figure, the same parts as those of the apparatus shown in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted. A T video signal from the outside is applied to a signal input terminal 41, and is band-divided into a 3MHz Y signal component and a chromaticity signal C component of 3 to 4.2MHz in an FM modulator 42. In particular, the luminance Y signal component is divided by the carrier wave. FM modulated. The chrominance signal component is led to a color amplifier 43 where it is downconverted to a signal of 1 MHz or less by means of a chrominance subcarrier. The low-frequency converted direct color signal from the color amplifier 43 and the Y-component FM modulation signal from the modulator 42 are superimposed and applied to the signal recording amplifier 44, where they are amplified to a desired recording level and sent to the next stage. The signal is sent to gate switch 45. Further, a field unit periodic pulse from a control switching pulse generator 46, which is a main part of the present invention, is applied to a gate switch 45 via a line 47, and the above-mentioned superimposition number is gated periodically by the gate switch 45. is added to the head assembly 14.

Further, a field unit square wave DC erasing current is applied to the head assembly 14 along with the gated signal, and the magnetic sheet 2
At the top, old information is pre-erased, and new information signals are recorded on the erased tracks. On the other hand, during playback, the gate switch 45 is switched in a playback mode, and the weak signal picked up by the head assembly 14 is applied to the playback preamplifier 48 via the gate switch 45 for level amplification, and then the signal gate switch 49 added to.

The gate switch 49 is switched to the reproduction side by a signal from the control pulse generator 46. The reproduced signal from the amplifier 48 is gated by a gate switch 49 and guided to the next stage FM demodulator 50 and color signal restoration circuit 51, where it is demodulated into the original video signal. Further, this demodulated video signal is applied to a signal processing circuit 52 controlled by control pulses from the pulse generator 46 described above. In the signal processing circuit 52, the reproduced video signal is modulated again by the carrier wave, and the modulated signal is further delayed by υH for each field signal through the ultrasonic signal delay line. Therefore, from the process circuit 52, h/2H
The delayed signal and the non-delayed signal are sent out alternately, and the processed reproduced video signal is taken out from the output terminal 53. Further, when slot-by-slot reproduction is performed using a single head, noise generated during the head transfer transition period in the process circuit 52 is gate removed.

Further, in the above reproduction system, the signal gate switch 49 gates the direct (modulated) signal from the modulator 42 to make the device into an E-E system mode. Here, the servo system of the device will be schematically explained.

A portion of the input video signal is applied to a vertical synchronization signal separator 54, where vertical synchronization pulses are separated and sent to a servo circuit 55,
It is added to the control pulse generator 46 and the process circuit 52. The servo circuit 55 receives the tone wheel pulse from the head 6 together with the vertical synchronizing pulse, compares the phases of both reference pulses, and controls the disc motor 5.
The rotation is controlled by synchronizing the phase with a vertical synchronization signal. Also,
The pulse generator 46 to which the pulse is applied receives an operation command signal from the beam mode control box 56 to generate the switching pulse via line 47, and outputs a pulse signal via line 57. The intermittent head drive source pulse motor 8 is controlled and driven by the signal. The pulse generator 46 also includes a pulse generator 46 that controls the proximity switch 18 when the head assembly 14 is moved to a predetermined position.
, limit switches 20 and 22 are applied, and the pulse motor 8 is controlled, as will be described later, to move the head assembly 14 to a predetermined retreat position. Next, the structure and operation of the control pulse generator 46 will be explained in the seventh section.
This will be explained with reference to FIG.

A step start pulse signal a (shown in FIG. 9A) from the vertical synchronizing signal separator 54 in FIG. 6 is input to the input terminal 60. The operation mode control circuit 61 operates according to various modes in response to the pulse signal and the mode control pulse from the operation mode control circuit 62, and sends control signals to the pulse oscillator 63 and the 1-drive pulse gate circuit 64, respectively. Output. The pulse oscillator 63 has a frequency of 30 Hz depending on the operation mode of the operation mode control circuit 61 related to the operation of the operation mode control circuit 61 and the operation mode of the head evacuation circuit 65 which is a main part of the present invention.
Or switch and output the 120z pulse signal. After passing through the gate circuit 64, this continuous positive pulse signal is sent to the head position counter 66 and the pulse motor drive amplifier control circuit 6.
7 respectively. The counter 66 outputs a pair of pulse signals to the control circuit 67 for reversing the pulse motor 8 when the head reaches the innermost and outermost positions. A signal is output to a recording/playback position search circuit 69, which is a main part of the recording/playback position search circuit 69. Furthermore, the control circuit 67 outputs 1-phase to 4-phase excitation signals b1 to B4 shown in FIG. It is driven intermittently. Further, a signal system mode pulse signal is output from the control terminal 71 of the operation mode control circuit 61. The head evacuation circuit 65 has a circuit configuration shown in FIG.
While being attached to the disk, the disk is rapidly moved in the inner circumferential direction to a retreat position 11 outside the recording track area. In addition, the search circuit 69
has the circuit configuration shown in Fig. 8, and after the device starts up, the 6th
When the ready signal is issued from the servo circuit 55 in the figure,
In conjunction with the operation of the operation mode control circuit 61, the head assembly 14 is moved intermittently in the outer circumferential direction from the retracted position 11. Furthermore, the search circuit 69 first locates the head assembly 14 at the innermost position 1. When the head position counter 66 is transferred to
The counter 66 is counted again using this as address O, and the inverted position at the outer circumferential position of the head assembly 14 is set to θ. , I is the reversal position at the inner circumference position. It has a function of instructing the motor drive control circuit 67 to operate in order to achieve this. Next, when the apparatus is in the recording/playback mode, that is, the magnetic sheet 2 is being rotated at a predetermined speed by the disk motor 5, and the head 14 is at position 1 above the sheet 2.

The head retracting operation when the power switch 80 and the pack drive switch 81 are opened while the head is moving intermittently between .theta.o and .theta.o will be described with reference to FIGS. 7 to 10. First, when the power switch 80 is opened during the recording/playback mode, which is the main part of the present invention, the head 14
The evacuation operation to the evacuation position will be explained. First, the switch connection mode between the power switch 80 and the pack drive switch 81 will be explained with reference to FIG. Switches 80 and 81 are both constituted by seesaw switches having two circuits, and FIG. 10 shows an embodiment in which both are opened. In the illustrated embodiment, the AClOOV power supply voltage being supplied to input terminal 120 is applied via line 121 to terminal 122, while switch contact 80a
is applied to terminal 123 via. Therefore, the power supply voltage at terminals 122 and 123 is applied to power relay 124, respectively.
Power is supplied to the power transformer 141 via the power switch 125 in the power supply or directly to the power transformer 141 to supply operating power to the device. In the mode in which power is supplied to the device, one input gate terminal 127 of the NAND gate 126 has a 30H
A pulse signal z is input, and a low level potential signal is applied to the other input gate terminal 128.

Note that the potential of the input gate terminal 128 is set by the power switch 80.
When the switch is on and the pack drive switch 81 is off, and when the switch 80 is on and the switch 81 is on, the potential is low, and when both switches 80 and 81 are on, either the switch 80 or 81 is turned off. It is considered to be a high level potential when In the above embodiment, a high level potential is output to the output side of the NAND gate 126. Further, the counter 129 is rendered inactive by a low-level potential signal applied via line 130, and the output line 131 of the counter 129 is at a low-level potential. Further, the potential of the input gate terminal 132 is at a low level potential because the head 14 is located within the recording/playback area of the sheet 2, and the potential on the output side of the NAND gate 133 is at a high level potential.

At this time, since the input gate terminal 135 of the NAND gate 134 is at a high level potential, its output side is at a low level potential. Input gate terminal 135 is switch 8
When 0 is on and switch 81 is off, the potential is low, and when both switches 80 and 81 are on, and when switch 80 is off and switch 81 is on, the potential is high. The low level potential signal from the NAND gate 134 is inverted and amplified by the inverter 136 to become a high level potential signal, which is applied to the base of the NPN transistor Tr for controlling the operation of the power relay.

Therefore, the transistor Tr is in a conductive state, and a current from the +12 power source is supplied to the coil 137 connected to the collector, and the power switch 125 is connected to the contact a as shown in the figure. On the other hand, since the pack drive switch 81 is closed, the AClOO
A 20V DC power source obtained from the power supply via a constant voltage circuit (not shown) is connected to the input terminal 138 to the switch contact 81a.
The signal is led to the terminal 139 via the servo amplifier 55 in FIG. In addition, the switching contact piece 80 of the switch 80
One circuit including the switching contact 81b of the switch 81 and one circuit including the switching contact piece 81b of the switch 81 are connected in parallel with each other, and their common contacts are grounded.

In the illustrated embodiment, since both switches 80 and 81 are closed, the inverter 82 of the head evacuation circuit 65
The terminal 140 connected to is set to an open potential, that is, a positive logic level potential, and the delay circuit 142 operates as described below. In the recording/playback mode described above, when the power switch 80 is opened, the power supply to the terminal 123 is cut off, but the AC input to the terminal 120 is
The lOOV supply voltage is still supplied to the power transformer 141 via a circuit via line 121, terminal 122, and the contact of power switch 125, and the components of the device are maintained in an operative state.

Further, by operating the switch, the potential of one input gate terminal 128 of the NAND gate 126 becomes a high level potential,
The output side of the NAND gate 126 has its input gate terminal 1.
The 30 Hz pulse signal applied to 27 is output as an inverted pulse signal and counted in a 240-decimal counter 129 which is set in the set mode by applying a high level potential through line 130. The output side of the 240-decimal counter 129 is held at a low level potential even after the above-mentioned switch operation, and is converted to a high level potential only after counting the 30 Hz pulse signal for 8 seconds.

In addition, by operating the above switch, the head evacuation operation is performed as described below, and when about 8 seconds have elapsed, the head 14
is completely at the retracted position 11, so when the output side of the counter 129 is set to a high level potential, the input gate terminal 1
32 is already at a high level potential.

Therefore, when the output side of the counter 129 becomes a high level potential, the gate output of the NAND gate 133 becomes a low level potential. In addition, since the input gate terminal 135 is set to a low level potential by the above-mentioned switch operation, the NAND gate 13
The gate output of No. 4 is converted to a high level potential. This potential is inverted and amplified by the inverter 136 to become a low level potential, and the transistor Tr is converted from a conductive state to a non-conductive state. Therefore, the coil 137 is demagnetized, the contact piece of the power switch 125 is switched from the contact a side to the contact b side, and the power supply to the power transformer 141 is cut off, thereby stopping the apparatus. Therefore, even if the power switch 80 is opened during the recording/playback mode, the power supply to each electrical system of the device (except for the drive system of the disk motor 1) is not immediately cut off, and each electrical system continues to operate from when the switch is opened. After a delay of 8 seconds, the power supply is cut off and the device becomes inactive.

Note that the delay circuit 142 having a delay function, which is shown surrounded by a broken line in FIG. It is also possible to replace 129 with a pulse oscillator.

Next, after opening the power switch 80, the power transformer 1
The retracting operation of the head 14 to the retracting position 11, which is performed within the delay time until the power supply to the head 41 is cut off, will be described with reference to FIGS. 8 and 9.

During the recording/playback mode, when switch 80 is opened at time t1, waveform c shown in FIG. 9C is applied to the input side of inverters 82 and 83 connected in series. This waveform c
Due to the change in the level of capacitor C1 and resistors R and R
The differentiator 84 consisting of NAND gates 85 and 86, the capacitor C2, and the resistor R3 operate, and the multivibrator 87 outputs a negative pulse signal d shown in FIG. (Indicated by 1 in Figure 9). Therefore, the output side of the mode holding circuit 90 consisting of NAND gates 88 and 89 becomes a waveform e shown in FIG. 9E, and becomes a high level potential (2). Therefore, the V pulse signal a applied to the input terminal 92 of the NAND gate 91 is inverted by the NAND gate 91 and becomes a waveform f shown in FIG. 9F.

This waveform signal is differentiated by the capacitor C3 and resistor R4 in the next stage, resulting in a negative polarity pulse g shown in FIG.
), a signal h shown in FIG. 9H appears on the output side of the mode holding circuit 95 comprising NAND gates 93 and 94 (
). In response to this signal h, the magnetic head 14 is rapidly moved to the retreat position 11 as described below. This signal h is connected to an inverter 96, a reset pulse generator 97 and a NAND gate 9.
8 inputs.

Nand Gate 98 is Nand Gate 99, 100, 101
Together, they constitute a drive pulse gate circuit 64. A negative potential signal 1 shown in FIG. 9 is output to the output side of the inverter 96 (5), and this output pulse causes the inverter 103 to
The input and output potentials of are inverted. Therefore, the pulse oscillator 63
The oscillation frequency of the output side is switched, and the continuous positive pulse signal on the output side becomes the continuous positive pulse signal K2 of 120 Hz, which is four times the frequency of the 30 z signal k1 during normal operation (during recording and playback), as shown in FIG. 9K. Become. This continuous positive pulse signal K2 is applied to each input gate 104 of NAND gates 99 and 100.
and added to 105. At this time, as for the NAND gate 99, since a high level potential is input to the input gate 106 only when the disk motor 5 is in the servo lock mode, when the pack drive switch 80 is opened as described above, the input gate 106 becomes a low level potential. input gate 1
Signal 1 is applied to signal 07, making it a low level potential.

Therefore, the output side of NAND gate 99 becomes a high level potential, and the signal of input gate 104 is blocked. Regarding the NAND gate 98, the input gate 110 receives the signal h1, the input gate 108 receives the pulse signal a1, the input gate 109 receives the output of the position detecting proximity switch 18, ie, the output of the position detecting proximity switch 18 shown in FIG.
A signal j shown in is added respectively. At this time, since the signal j is at a low level potential, the output of the NAND gate 99 is at a high level. In addition, for the Nando game port 00, the input gate 111 receives a signal h1 from the input gate 105.
A signal K2 is applied to the input gate 112, and a high-level potential signal obtained by inverting the signal j by an inverter Rll3 is applied to the input gate 112, respectively. Therefore, the output signal K2 from the pulse oscillator 63 applied to the input gate 105 appears on the output side of the NAND gate 100 as an inverted and amplified signal.
This signal is applied to one input gate of the NAND gate 101 in the next stage. At this time, since the other input gates of the NAND gate 01 are at a high level potential, a signal obtained by inverting and amplifying the above signal, that is, a pulse signal K2, is output to the output terminal 114 of the NAND gate 101. This 120Hz pulse signal K2 is applied to the pulse motor 1 drive control circuit 67 in FIG.
The pulse motor phase excitation pulse is obtained by

This signal is applied to the pulse motor 8 via the next-stage pulse motor 1 drive circuit 70, as in the case of recording and reproducing, and the motor 8 is moved intermittently at high speed. The pulse motor 8 directs the head 14, which is moving intermittently on the sheet 2, toward the inner circumference of the sheet, that is, toward the proximity switch 18, because the output signal 1 of the inverter 96 is at a low level potential. It is rotated with the direction of rotation regulated for fast forwarding.
When the head 14 is fast forwarded and reaches within the operating range (approximately 3 mm) of the proximity switch 18 at time T2, the switch 1
8 is operated by a permanent magnet piece 19, and this output side is converted from a low level potential to a high level potential.

Note that when the proximity switch 18 is activated, the head 1
4 is head cue position 1 in Figure 3. , and is located near the retreat position 11. This level change causes the input gate 109 of the NAND gate 98 and the NAND gate 10 to
The potentials of the 0 input gates 112 are inverted, so that the input gate 109 has a high level potential and the input gate 112 has a low level potential. When the input gate 109 becomes a high level potential, a signal obtained by inverting and amplifying the V pulse signal a input to the input gate 108 appears on the output side of the NAND gate 98, and is sent to the NAND gate 101.

On the other hand, as for the NAND gate 100, the 120 Hz pulse signal K2 of the input gate 105, which has been passed until now, is blocked, and the output side becomes a high level potential. Therefore, the output signal from the output terminal 114 of the NAND gate 149 is switched to a 60Hz pulse signal indicated by K3 in FIG. be done. Therefore, the magnetic head 14
is precisely positioned on the same track i1 on the sheet as shown below, and is in a retracted state. In this retracted position, the head 14 is located at a position sensed by the proximity switch 18, that is, within the operating range (approximately 3 mm) of the proximity switch 18. Further, the high level potential on the output side of the proximity switch 113 is applied as a high level potential signal to one input gate of the NAND gate 116 via inverters 113 and 115.

On the other hand, the input gate of the inverter 117 is
A phase excitation reference pulse l having a waveform shown in is applied. Therefore, the gate output of the NAND gate 116 becomes a signal m shown in FIG. 9M, which is at a low level potential during a period when both signals j and l are at a high level potential (6). Signal m is applied to the reset gate inputs of NAND gate 89 in mode hold circuit 90 and NAND gate 94 in mode hold circuit 95, respectively. When the NAND gate 89 reset input signal level changes to a low level potential (6), the output side of the circuit 90 becomes a low level potential. In the next stage NAND gate 91, one gate input is converted to a low level potential (7), and the V pulse a entering the other input gate is applied to the gate 91.
is prevented from passing through, and the output side of the gate 91 becomes a high level potential (8). On the other hand, as the NAND gate 94 reset input signal level changes to a low level potential,
The output side of the mode holding circuit 95 becomes a low level potential (9
).

This low level potential signal is applied to the input gate 110 of the NAND gate 98 and the input gate 11 of the NAND gate 100, and the output side of each gate 98 and 100 becomes a high level potential. As a result, the three input gate signals of the NAND gate 101 are all fixed at a high level potential, the output terminal 114 becomes a high level potential, the motor and driving excitation current to the pulse motor 8 is cut off, and the motor 8 is stopped. The head 14 is stopped exactly at the predetermined retraction position 11. At the same time, the output side of the inverter 96 becomes a high level potential (0), and the oscillation frequency of the oscillator 63 is switched to the normal operation frequency of 30 Hz.

Furthermore, the signal converted from the high level potential to the low level potential is applied to the resetting pulse generator 97, differentiated by the differentiator circuit inside the generator, and further operates the monostable multivibrator to generate the signal shown in FIG. 9N. A set pulse n is formed. This reset pulse n is sent to each part and the device is converted back to the stop mode configuration. The above head evacuation operation is performed after opening the pack drive switch 80.
Done within seconds.

Therefore, in the state where the head 14 is completely moved to the retracted position 11, the power supply to the power transformer 141 is cut off, and the apparatus is converted to the stop mode. In the above embodiment, the head 14 is transferred to the shelter position 11 at a frequency speed of 120 Hz, which is four times the normal intermittent step transfer speed of 30 Hz. By driving at an arbitrary frequency, the retracting operation of the head 14 to the retracting position can be performed more sharply. Also, at this time, the pulse motor 8
Even if the head 14 is driven at a frequency speed of 30 Hz as in normal driving and the head 14 is moved at the same speed as in normal intermittent step movement, the head 14 will be moved to the shelter position before the power supply to the device is cut off. Therefore, no problem will occur. Next, in the recording mode, when the pack drive switch 81 shown in FIG. This causes the magnetic sheet 2 to rotate due to inertia.

However, the power transformer 141 is maintained in an operating mode, and the pulse motor drive system is maintained in a power supply mode. Note that the power switch 125 is switched to the contact b side after the switch 81 is opened. Also, by opening the switch 81, the eighth
In the figure, waveform c is applied to the inverter 82, and the head 14 is moved to the retreat position 11 in the same manner as described above, and the device gradually rotates the sheet 2 with the head 14 reaching the retreat position 11. It reduces and stops and is converted into a kind of stop mode.

Furthermore, even if the power switch 80 and the pack drive switch 81 are opened at the same time during the recording/playback mode, the device is converted to the stop mode by cutting off the power supply to the electrical system after the head 14 has been moved to the evacuation position 11. .

Next, due to circumstances such as repair of the head mechanism, if the head mechanism is manually operated and the head is moved from the retracted position and placed in the recording/playback area, the device is placed in stop mode. The head evacuation operation when power is supplied to the apparatus by closing 80 will be described with reference to FIGS. 11A to 11D.

When the power switch 80 is closed at time T3, the power transformer 141 in FIG.
When the power supply voltage is supplied, the potential on the input side becomes the waveform a! shown in FIG. 11A. The device will start up and become operational.

Furthermore, when the switch 80 is closed, the output side potential of the proximity switch 18 is at a low level potential, and the input gate to the NAND gate 116 after passing through the inverters 113 and 115 is at a low level potential. Therefore, the output potential of the NAND gate 116 becomes a high level potential as shown in the waveform Bt shown in FIG. 11B, and the signal BI is applied to one input gate of the NAND gate 89 of the mode holding circuit 90. Furthermore, when the power switch 80 is closed, regardless of whether the pack drive switch 81 is opened or closed,
The midpoint potential between the resistors R1 and R2 of the differentiator 84 increases toward the midpoint potential of the +B power supply supplied to the terminal of the resistor R1 by a time constant determined by the time constant of the resistors R1 and R2. Therefore, the output side of the NAND gate 85 becomes a high level potential with a slight time delay, and as shown in FIG.
is output. Therefore, the monostable multivibrator 87 outputs a negative pulse signal d1 shown in FIG. 11D.
This negative pulse signal d1 has the same function as the negative pulse signal d shown in FIG. 14 is quickly returned to the retreat position 11. The head quick return operation is performed regardless of whether the pack drive switch 81 is closed or opened at the time the power switch 80 is opened.
This is always done when switch 80 is closed. Next head 1
4 is located at the retracted position 11 and the head transfer operation is performed when the power switch 80 is closed.
This will be explained with reference to FIGS. 1E to 1H.

By closing the power switch 80, power is supplied to the power transformer 141 in FIG. 10, and the electrical system of the apparatus becomes operational. When the switch 80 is closed, the proximity switch 18 is sensing the head 14 and therefore outputs a high level potential. This signal is amplified as a high-level potential signal via inverters 113 and 115, and is applied to one input gate of the NAND gate 16. Further, the phase excitation reference pulse 2 is instantaneously applied to the inverter 117, and a high level potential is applied to the other input gate of the NAND gate 116. Therefore, the output side of NAND gate 116 becomes a low level potential, which is applied to the reset input gates of NAND gates 89 and 94. Here, Nand Gate 88
Similarly to the above, the negative pulse signal dl is applied to the set input gate of
is applied, and the output side of the holding circuit 90 becomes a high level potential for a short period of time, and an attempt is made to move the head 14. However, since the reset input gate of the NAND gate 89 is set to a low level potential, the head 14 is not transferred and remains at the evacuation position. It is held at 11.

In the above embodiment, when the pack drive switch 81 is closed, the disk motor 5 is started, and the motor 5 is servo-locked within 10 seconds after the switch is operated.

When the motor 5 is servo-locked to rotate at a predetermined speed, a high-level ready signal is applied to the input gate 106 of the NAND gate 99 in the 1-drive pulse gate circuit 64. At this time, the input gate 107 of the NAND gate 99 receives a high level potential signal and the input gate 104
A 30 Hz pulse signal from a pulse oscillator 63 is applied to each. Therefore, a 30 Hz pulse signal is passed through the output side of the NAND gate 99. This pulse signal is inverted and amplified by an inverter 150 to become a clock pulse, which is added to a 150-decimal counter 151 and counted there. The 150-decimal counter 151 outputs a pulse signal whose level changes when counting the 15th, 75th, and 150th 30Hz clock pulses.

That is, when the 15th pulse is counted, the terminal 152
A positive pulse signal is output to terminals 153 and 154 when the 75th and 150th pulses are counted. The positive pulse signals outputted to the terminals 153 and 154 serve as signals for determining the reversal position when the head 14 is intermittently conveying the sheet 2 in the inner and outer circumferential directions. Further, a low level potential signal GI shown in FIG. On the other hand, the output side of the NAND gate 116 is at a low level potential as the signal e1 shown in FIG.

Therefore, on the output side of the NAND gate 155, as shown in FIG.
A high-level potential signal f1 shown in (◎) is output. Further, in the above embodiment, a 30 Hz pulse signal is output from the output terminal 114 of the drive pulse gate circuit 64,
The pulse motor 8 is driven once, and the head 14 is moved intermittently from the retreat position 11 toward the outer circumferential direction of the sheet.

When the 15th pulse is output from the terminal 114, the video core 33 and erase core 34 of the head 14 are at the innermost position 1 of the recording/playback area in FIG.

It is attached at a position corresponding to . Also, head 1
4 is position 1. During the movement, the head 14 becomes out of the detection range of the proximity switch 18 and the NAND gate 1
The output side of the NAND gate 155 is held at a high level potential as shown by waveform e●, while the output side of the NAND gate 155 is held at a high level potential. Further, when the counter 151 counts the 15th pulse signal, the high level potential of the signal end is applied from the counter 151 to the NAND gate 55, and the output side signal f1 of the NAND gate 155 changes from the high level potential to the low level potential. be done. This level change is differentiated by a differentiator 159 consisting of a capacitor C4 and resistors R and R6 to form a negative pulse differential wave, which is applied to a monostable multivibrator 162 consisting of NAND gates 160, 161, a capacitor C5 and a resistor R6. As a result, the multivibrator 162 generates a negative pulse signal h' shown in FIG. 11H (@). This negative polarity pulse signal h1 is applied as a set pulse signal to the NAND gate 156 in the circuit 158, the output side of the circuit 158 becomes a low level, and the output side of the NAND gate 155 becomes a high level potential again (◎).
The output signal via 2 is blocked.

Further, the pulse signal H6 is applied to the counter 151 as a negative reset pulse through a NAND gate 163 and an inverter 164, and the counter 151 is reset. In addition, in the above embodiment, the retracted position 11 of the head 14
Cue position 1 of the track used. The transfer to is completed. In the above practical example, the head 14 is moved to the cue position using the pulse motor 8 at a frequency of 30 Hz, but the pulse motor 8 may be moved at a frequency of 60 Hz or 120 Hz.
By driving the head at a frequency speed of , it is possible to perform the cueing operation of the head at a higher speed. The pulse motor 8 has the head 14 at the cue position 1.

Even after being transferred to the drive pulse gate circuit 64
The intermittent circuit is continued by the excitation current generated based on the 30 Hz continuous pulse signal from the pulse oscillator 63 outputted from the output terminal 114 of the head 14 into the recording/playback area on the sheet 2. Further, the counter 151 indicates that the head 14 is at cue position 1. The pulse oscillator 63 outputs oscillation, and the NAND gate 9
9. Start counting the 30Hz pulse signal applied via the inverter 150. The head 14 is moved to the cue position 1 by the drive of the pulse motor 8.

The fifth
In the figure, an outbound track GtO-Gtn is formed and recording/playback operation is started. When the pulse motor 8 has performed the stepping operation 75 times, that is, when the counter 151 has counted the 75th pulse signal, the head 14 is at the outermost circumference position θo, that is, track G. has been transported to the position to be traced. At this time, a positive pulse signal is output from the terminal 153 of the counter 151, and the rotating direction of the pulse motor 8 is reversed. For this reason, the head 14 is moved intermittently in the inner circumferential direction to move the return tracks B, O to Btn to the outward track Gt.
They are formed alternately and sequentially for O-Gln. When the pulse motor 8 repeats the stepping operation 75 times after starting the reverse rotation, that is, when the counter 151 counts the 150th pulse, the head 14 traces the innermost circumference position (heading position) 10, that is, the track Btn. It has been moved to the location where it will be located. At this time, a positive pulse signal is outputted from the terminal 154 of the counter 151, the rotational direction of the pulse motor 8 is reversed, and the head 14 is transported while staying on the outgoing track. Therefore, in the recording and playback operation, the head 14 is at position 1 above the sheet 2. and θ. This is done by going back and forth between. The time required for one round trip of the head 14 is about 5 seconds. Next, in order to prevent damage to the device when an abnormality occurs in the control operation of the pulse motor 8 during the recording/playback mode and the head 14 moves out of the predetermined recording/playback area to a position detected by the limit switch 20 or 22. The operation of returning the head 14 to the predetermined retreat position 11 will be explained. The outer limit switch 22 has one switch terminal grounded and the other switch terminal connected in parallel to the power switch 80 and the pack drive switch 81 to the input side of the inverter 82 in FIG. It is located at the location. When the head 14 moving toward the outer circumference of the sheet 2 is moved abnormally and the limit switch 22 is opened by engaging the contact piece with the protrusion 21,
The input potential to the inverter 82 changes from a high level potential to a low level potential. This mode is the same as when the switch 80 or 81 is opened during the recording/playback mode, and the head 14 is quickly returned to the head retreat position 11 in the same manner as described above. On the other hand, an inner limit switch 20 is also provided in the same manner as the outer limit switch 22, and when the head 14 that is being transferred in the inner circumferential direction of the sheet 2 is abnormally transferred and the switch 22 is opened, the pulse motor 8 is reversely rotated. The head 14 is then transferred to the shelter position 11.

Note that the limit switches 20 and 22 have one terminal of each switch set to ground potential and the other terminal connected to a part of the reset pulse generator 97, as in the conventional case.
0 and 22 are activated, the control operation of the pulse motor 8 can be stopped by sending out a set pulse from the terminal 165 to each part.

Note that the head evacuation device of the present invention is not limited to the pack-type recording/reproducing device of the above practical example, but can be similarly applied to devices in which the rotating recording medium is a plated rigid disk or a magnetic drum. And still image broadcasting and CAT
The present invention is effective when applied to a fixed head type one frame memory device used as a terminal frame memory.

In the latter case, for example, the head is attached via a delay electromagnetic solenoid or the like, and when the rotation of the magnetic body is stopped, the head is moved to the retracted position by a spring spring, and after the rotation speed of the magnetic body reaches a predetermined speed after startup, the above-mentioned delay is performed. The head is moved into the recording track area by driving an electromagnetic solenoid. In addition, in the above practical example, the head assembly 14 is configured as a three-point support type with three cores, so the retracted position of the head assembly 14 is deviated by a predetermined distance outside the recording track area. However, if the head assembly is configured with a single video core, the head retraction position may be located outside the recording track area by a minute interval width corresponding to the single track width. Of course it's good. Furthermore, the head evacuation device of the present invention can be similarly applied to a device that records video signals, audio signals, etc. by forming continuous spiral recording tracks on a rotating recording medium.

As described above, the head evacuation device for a recording/reproducing apparatus using a rotating recording medium according to the present invention includes: a head transporting means for conveying the head in a radial direction; and a rotation driving means for rotating the rotary recording medium. , a first detection means for detecting that the head is at a predetermined evacuation position outside the recording/reproducing track area, and when the recording/reproducing apparatus is switched from the recording/reproducing mode to the stop mode and from the stop mode to the recording/reproducing mode a head evacuation/transfer means which operates when the first detection means does not detect the head and evacuation transports the head to a evacuation position outside the recording/reproducing track area; a stopping means for detecting that the head is in the position and stopping the evacuation/transfer means; and a reversing control means for reversing the head when it reaches the boundary of the recording/reproducing track area when in the recording/reproducing mode. Since the head is configured as shown in FIG. Since the head is configured to be moved and stopped at the above-mentioned retreat position in response to the detection operation of the second detection means, damage to the recording surface within the recording track area of the recording medium can be completely prevented. Furthermore, even if an abnormality occurs in which the head is moved outside the recording track area, the head can be moved to a predetermined evacuation position, thereby preventing various inconveniences, and furthermore, the circuit can be relatively simplified. It has the advantage that it can be easily constructed and manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal front view of an embodiment of a recording and reproducing apparatus using a rotating recording medium to which a head evacuation device according to the present invention is applied, and FIG. 2 is a front view of a head transport mechanism of the apparatus shown in FIG. FIG. 3 is a perspective view showing the relative position of the head transported by the head retract position according to the present invention with respect to the magnetic sheet, and FIGS. 4A and 4B respectively show the structure of the head assembly applied to the apparatus of the present invention. Perspective and plan views shown in Figures 5A and B.
FIG. 6 is a diagram showing a recording track pattern formed on a magnetic sheet by the recording/reproducing apparatus shown in FIG. 1 and a partially enlarged view thereof, FIG. FIG. 7 is a block diagram showing the configuration of a control pulse generator which is a main part of the head evacuation device according to the present invention in FIG. 6, and FIG. 9A and 9B are diagrams showing the waveforms of various parts in FIG. 7 in recording and playback mode, respectively, and C to N in the same figure are circuit diagrams showing a specific circuit configuration of one practical example of a driving pulse gate circuit. A diagram showing the waveforms of various parts in FIG. 8 during the head evacuation operation when the power switch is opened during the recording/playback mode, and FIG. 10 shows the power switch and power switch applied to the recording/playback apparatus shown in FIG. 1. A wiring diagram of a drive switch and a circuit diagram of one embodiment of a main power delay circuit,
FIGS. 11A to 11H are diagrams showing waveforms at various parts in FIG. 8 during the head evacuation operation when the apparatus is changed from the stop mode to the recording/reproducing mode. 1... Seat pack assembly, 2... Magnetic sheet, 5... Disc motor, 6...
・・Tone wheel pickup head, 8・・・・
... Pulse motor for head transfer, 14 ... Video head assembly, 18 ... Proximity switch for detecting reference position, 20, 21 ... Limit switch,
33...Video head core, 34...
Leading erase core, 35...Dummy core, 46.
...Control switching pulse generator, 5
0...FM demodulator, 51...Color signal restoration circuit, 54...Vertical synchronization signal separator, 5
5... Servo circuit, 56... Ri mode control box, 61... Operation mode control circuit, 62... Operation mode control circuit, 63...
...Pulse generator, 64...1 Drive pulse gate circuit, 65...Head evacuation circuit, 66
... Head position counter, 67 ... Pulse motor 1 drive amplifier control circuit, 68 ... Head position display device, 69 ... Recording playback position search circuit, 70...Pulse motor, drive circuit, 80
...Pack drive switch, 81...
・Power switch, 84,159...differentiator,
87,162... Monostable multivibrator,
90, 95, 158...Mode holding circuit, 97
...Reset pulse generator, 98-101...
... NAND gate, 124 ... Power relay, 125 ... Power switch, 129 ...
240-decimal counter, 141... Power transformer, 142... Delay circuit, 151...
・150 decimal counter.

Claims (1)

[Scope of Claims] 1. In a recording and reproducing apparatus that records and reproduces information signals by moving a head on a rotating recording medium in a radial direction and having a retreat position outside a recording and reproducing track area, the head is moved in a radial direction. a head transporting means for transporting the recording medium along with it; a rotational drive means for rotating the rotary recording medium; a first detection means for detecting that the head is at a predetermined evacuation position outside the recording/reproducing track area; When the playback device is switched from the recording/playback mode to the stop mode, or when the stop mode is switched to the record/playback mode, and the first detection means does not detect the head, the first detecting means operates to detect the head. a head evacuation transfer means for evacuation-transferring to a evacuation position outside the recording/reproducing track area; a stop means for detecting that the head is in the evacuation position and stopping the evacuation/transfer means; 1. A head retracting device for a recording/reproducing apparatus using a rotating recording medium, comprising a reversal control means for reversing the head when the head reaches a boundary of a reproducing track area. 2. The apparatus further includes a second detecting means for detecting that the head has been moved outside the recording/reproducing track area during the recording/reproducing mode and driving the evacuation/transfer means, and the detecting operation of the second detecting means Claim 1 is characterized in that the head is moved and stopped at the retracted position in accordance with the above.
A head evacuation device in a recording/reproducing apparatus using the rotating recording medium as described in 1.