JPS63160001A - Rotary head device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To supply a stable power supply to a recording and reproducing amplifier built in a rotary head device by supplying selectively an output of an AC signal generator to the rotary head device via the rotary transformer synchronously with a rotary head noncontact region detecting pulse. CONSTITUTION:A detection signal from rotary pulse detection heads 37, 37' is sent to a gate pulse generator 40 and the noncontact region between a wound magnetic tape 33 and rotary heads 1, 1' is detected pulses (g), (h) synchonously with the rotation of the heads 1, 1'. An output of the AC signal generator 43 is fed selectively to primary coils 44, 44' of the rotary transformer driven by the heads 1, 1'. Then the output is supplied to the AC signal rectifier 47 by the action of an AC signal detecting signal detector 47. The output of the rectifier 47 is applied as the power supply of recording and reproducing amplifiers 49, 49'. Thus, a stable power supply is applied to the recording and reproducing amplifier connected to the rotary head and driven at a high speed to attain the recording and reproduction for a long time.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is mainly applicable to recording and reproducing video signals on magnetic tape.
The present invention relates to a rotary head device for a magnetic recording/reproducing device (hereinafter referred to as a VTR).

2. Description of the Related Art Conventionally, a rotating head device for a pVTR inputs a playback signal from a rotating video head to a rotating transformer on the primary side that rotates together with the video head, and a corresponding fixed secondary side to a preamplifier of the VTR. A common configuration was to add In recent years, VTRs have become more densely recorded and smaller and lighter, and rotary head devices have been provided that have built-in preamplifiers and recording amplifiers, are directly connected to a video head, and are rotated. A conventional example will be described below using drawings.

FIG. 4 shows a cross-sectional view of a conventional rotary head device, in which 1 is a rotary head capable of reproducing recorded signals from a magnetic tape (not shown). Reference numeral 2 is a helad base, and the rotary head 1 is adhesively fixed to the tip thereof, and is fixed to the lower end of the rotary cylinder 4 with screws 3. 5 is a fixed lower cylinder capable of guiding a magnetic tape on its outer peripheral surface. Reference numeral 6 denotes a rotating disk, which is fixed to a rotating shaft 7 at the center and is rotatable while being supported by bearings 8 and 8'. 9 is a thrust stopper fixed to the lower end of the rotating shaft 7 with a screw 10; 11 is an electric motor rotor that is fastened to the thrust stopper 9 with a screw 12; 13 is adhesively fixed to the rotor of the electric motor. 14 is the stator coil of the electric motor.

When energized, rotational force is generated in the rotor 13. 15 is a spacer between the rotating disk 6 and the bearing 8; 16 is a screw for tightening and fixing the rotating cylinder 4 to the rotating disk 6;
Reference numeral 17 denotes a primary side core of a rotary transformer adhesively fixed to the lower part of the rotary disk 6, and a rotary head 1' provided at a distance of 1000 mm from the rotary head 1 and the rotary head 1.
The groove has a primary winding connected to each of the windings (not shown). Reference numeral 18 denotes a secondary core of the rotary transformer which is adhesively fixed inside the fixed lower cylinder 5 opposite to the primary core 17 of the rotary transformer, and a secondary winding is provided in the groove. 19 is a slip ring mounting tool which is fastened to the upper end of the rotating disk 6 with a screw 21 via a spacer 20'i; 22 is a slip ring holder that insulates and holds the electrodes 23 and 24 of the slip ring; The ring attachment is adhesively fixed to the tool 19. 25
．． 28 is a brush that is in contact with the electrodes 23 and 24 of the slip ring, 27 is a brush holder that holds the edges of the brushes 2s and 26t, and the brushes on the VTR main body are attached to the plate 2.
8 is fixed with adhesive. 29 is a circuit board fixed to the upper part of the rotating cylinder 4 with screws 30; 31 is a preamplification means configured on the circuit board 29;
The reproduced signals from the rotary transformer are individually amplified and applied to the primary winding of the primary core 17 of the rotating transformer.

Next, FIG. 6 shows a connection diagram showing the flow of the reproduction signal from the rotary head 1.1' in the conventional rotary head device.
The primary winding 1 is added to the primary winding 1 and is subjected to predetermined signal processing, and is provided in the groove of the primary core of the rotary transformer = 17.
Secondary core 1 of the rotating transformer joins A&, 17b.
The signal is outputted to the secondary windings 18&, 18b provided in the groove portion of No. 8, and is added to the subsequent signal processing circuit. Preamplification means 31
The power source for operating the slip ring electrode 23.
+Vcc through brush 25, 2θ which is in contact with 24
, GND are respectively supplied. The part surrounded by a broken line 32 in FIG. 5 rotates together with the rotary cylinder 4, and the area outside the broken line 32 indicates a fixed part.

Next, the operation in the conventional example shown in FIGS. 4 and 5 is as follows.

When the VTR is put into the playback state, the 14 motor stator coils are energized and rotational force is generated in the rotor 13, which connects the thrust stopper 9 fixed to the rotor 13, the rotating shaft 7, the rotating disk 6, and the primary rotating transformer. Side core 17, rotating cylinder 4, rotating head 1゜a, slip ring electrode 2
3. A part fixed to a rotating shaft such as 24 rotates. +V is then applied to the preamplifying means 31 through the brushes 25.26 in contact with the electrodes 23.24 of the slip ring.
When CC and GND power is supplied and the preamplifier 31 becomes operational, it amplifies the reproduced signals from the rotary heads 1 and 1' individually and outputs the primary winding 172L of the primary core 17 of the rotary transformer. , 17b, and a corresponding secondary winding 18a of the secondary core 18.

18b, and is added to the subsequent signal processing circuit.

Problems to be Solved by the Invention As described above, in the conventional rotary head device described above, the power source for operating the preamplifier means 31 is supplied to the brushes 25. 26, the slip ring electrodes 23 and 24 also rotate together with the rotary head 1° 1' when the VTR is in the playback state, and the corresponding brush 25
．． 26 will be in rotating contact with the electrodes 23, 24 of the slip ring.

Therefore, during long-term playback of the VTR, the rotating slip ring electrodes 23.24 and brushes 25.2
The contact part with the slip ring electrode 23.6 may wear out, and dirt and dust in the air may adhere to the contact part, causing damage to the slip ring electrode 23.
The state of electrical contact between 24 and the brushes 25 and 26 changes,
For reasons such as the inability to provide stable power supply to the preamplifier means 31, this has been a cause of deterioration in the reliability of the VTR.

However, in recent years, high-density recording of VTRs has progressed, and for example, NT
High-quality VT with approximately twice as many horizontal scanning lines as SC video signals
The rotary head device used in R and TR converts NTSC video signals into M/D and digitally records them on magnetic tape. High-speed rotation is required.VTR rotary head devices ((slip rings 23, 24 and brush 25 described above) that are compatible with these high-speed rotations are required.
．． 28, the slip rings 23, 24 and the brushes 25, 26 come into contact with high speed rotation, which shortens the wear time of each, and the VT
There were drawbacks such as lowering the reliability of R. The present invention eliminates the drawbacks of the conventional recording medium, which is connected to a rotating head and rotates.

The purpose is to provide a stable power supply to regenerative amplifiers.

Means for Solving the Problems The present invention provides rotating head non-contact area detection means for detecting a non-contact area between a wound magnetic tape and a rotating head and generating a pulse synchronized with the rotation of the rotating head; an AC signal generator that generates an AC signal when energized; a rotating transformer that transmits signals between a primary rotating coil that rotates together with the rotating head; and a corresponding secondary fixed coil;
The secondary fixed coil of the rotary transformer and the AC signal generator are selectively connected in synchronization with the pulse of the rotary head non-contact area detection means, and the AC signal from the AC signal generator is connected to the AC signal generator. a secondary side switch means for transmitting information to the primary side rotating coil, and connected to the rotating head;
a recording/reproducing amplifier that performs predetermined signal processing; an alternating current signal rectifier that rectifies the input AC signal and applies its output to the power source of the recording/reproducing amplifier; A rotary head device for a magnetic recording and reproducing device, comprising a primary side switch means for detecting an alternating current signal from the alternating current signal generator and connecting a primary rotating coil of the rotary transformer to an input of the alternating current signal rectifier. be.

According to the above-described structure, the present invention rotates the rotary head when the VTR is in a bad operating condition, winds a magnetic tape around the outer peripheral surface of the rotary head device, and energizes the AC signal generator to put it into operation, thereby producing an AC signal. to occur. In this state, the rotary head non-contact area detecting means generates a pulse corresponding to the non-contact area between the wound magnetic tape and the rotary head and synchronized with the rotation of the rotary head. The secondary side switch means is operated in synchronization with this pulse to connect the secondary side fixed coil of the rotating transformer and the AC signal generator, and the AC signal from the AC signal generator is sent to the primary side coil of the rotating transformer. introduce. The transmitted AC signal is detected and the primary side switch means is brought into operation, the primary coil of the rotary transformer and the input of the AC signal rectifier are connected, and the AC signal is applied to the AC signal rectifier, rectified, and recorded. , acts to add to the power supply of the regenerative amplifier.

EXAMPLE Hereinafter, an example of a rotary head device according to the present invention will be described with reference to the drawings. Note that parts unrelated to the present invention are designated by the same numbers and symbols as those of the conventional example shown in FIGS. 4 and 5, and redundant explanation will be omitted. FIG. 1 shows a wiring diagram in an embodiment of the rotary head device of the present invention, in which 33 is a magnetic tape wound and guided around the outer peripheral surfaces of the rotary cylinder 4 and the fixed lower cylinder 5. It is possible to record and play back signals via.

34.35 is the rotating cylinder 4 and the fixed lower cylinder 5
The magnetic tee 1330 is wrapped around the tape guide that regulates the corner, and 36.36' is the arrow a along with the rotating cylinder 4.
It rotates integrally in the direction of rotation axis 7.

Therefore, during long-term playback of the VTR, the rotating slip ring electrodes 23.24 and brushes 25.2
The contact part with 6 may wear out.

Airborne dirt, dust, etc. may adhere to the contact area, and the electrical contact between the slip ring electrodes 23 and 24 and the brushes 25 and 26 may change, making it impossible to stably supply power to the preamplifier means 31. For this reason, the reliability of the VTR was reduced.

In addition, in recent years, VTRs have become more densely recorded, for example, NT
High-quality VT with approximately twice as many horizontal scanning lines as SC video signals
The rotary head device for digital "/TR" which converts R and N'rSC video signals into M/D and digitally records them on magnetic tape has a rotating head rotation speed of 4 to 6 times more than that of conventional rotary head devices. The above-mentioned slip rings 23, 24 and brushes 25 are required to rotate at high speeds.
．． 26, the slip rings 23, 24 and the brushes 25, 26 come into contact with high speed rotation, which shortens the wear time of each, and the VT
There were drawbacks such as lowering the reliability of R. The present invention aims to eliminate the conventional drawbacks and to enable stable power supply to a rotating recording/reproducing amplifier connected to a rotary head.

Means for Solving the Problems The present invention provides rotating head non-contact area detection means for detecting a non-contact area between a wound magnetic tape and a rotating head and generating a pulse synchronized with the rotation of the rotating head; an AC signal generator that generates an AC signal when energized; a rotating transformer that transmits signals between a primary rotating coil that rotates together with the rotating head; and a corresponding secondary fixed coil;
The secondary fixed coil of the rotary transformer and the AC signal generator are selectively connected in synchronization with the pulse of the rotary head non-contact area detection means, and the AC signal from the AC signal generator is connected to the AC signal generator. secondary side switching means for transmitting the signal to the primary side rotating coil;

A recording device that is connected to a rotating head and performs predetermined signal processing;
a regenerative amplifier; an AC signal rectifier that rectifies the input AC signal and applies its output to the power source of the recording/reproducing amplifier; and an AC signal generator that rectifies the input AC signal and applies the output to the power source of the recording/reproducing amplifier; A rotary head device for a magnetic recording and reproducing device, comprising a primary side switch means for detecting a signal and connecting a primary side rotating coil of the rotary transformer and an input of the AC signal rectifier.

According to the above-described structure, the rotary head is rotated when the VTR is in use, a magnetic tape is wound around the outer peripheral surface of the rotary head device, and the AC signal generator is energized to be in operation, and the AC signal generator is activated. to occur. In this state, the rotary head non-contact area detecting means generates a pulse corresponding to the non-contact area between the wound magnetic tape and the rotary head and synchronized with the rotation of the rotary head. The secondary side switch means is operated in synchronization with this pulse to connect the secondary side fixed coil of the rotating transformer and the AC signal generator, and the AC signal from the AC signal generator is sent to the primary side coil of the rotating transformer. introduce. The primary side coil of the rotary transformer is connected to the input of the AC signal rectifier, and the AC signal is applied to the AC signal rectifier and rectified. It acts to add to the power supply of the recording and reproducing amplifier.

EXAMPLE Hereinafter, an example of a rotary head device according to the present invention will be described with reference to the drawings. Note that parts unrelated to the present invention are designated by the same numbers and symbols as those of the conventional example shown in FIGS. 4 and 5, and redundant explanation will be omitted. FIG. 1 shows a wiring diagram of an embodiment of the rotary head device of the present invention, in which 33 is a magnetic tape wound and guided around the outer peripheral surfaces of the rotary cylinder 4 and the fixed lower cylinder 6. It is possible to record and play back signals via.

34.36 is the rotating cylinder 4 and the fixed lower cylinder 5
The magnetic tee 1330 is wrapped around the tape guide that regulates the corner, and 36.36' is the arrow a along with the rotating cylinder 4.
direction, a signal is generated on the rotating shaft and applied to one end 41-b, 41'-b of the secondary switch 41.41'. Furthermore, as the rotary cylinder 4 rotates, the rotary pulse detection head 37 detects the pulse e in FIG.
The rotation pulse shown in is generated. Similarly, the rotational pulse detection head 3 generates a rotational pulse shown in FIG. That is, the rotational pulse e in Fig. 3 is 38-
At timing 1, the rotary head 1 passes the contact end portion 38 with the magnetic tape 33 shown in FIG. 1, and at timing 3B-1', the rotary head 1' comes into contact with the magnetic tape 33 shown in FIG. It passes through the termination section 38. Similarly, the rotational pulse f in FIG.
This results in passing through the point where the contact starts. The rotation pulses e and f generated at the above timing are generated by the gate pulse generator 4.
0, and the built-in monostable multifunction operates to output the gate pulses shown in g and 1 in FIG. 3, respectively. This gate pulse generator is used when the E heads 1 and 1' are connected to the magnetic tape 3.
The secondary switch 41.4 is configured to output between the non-contact area from the contact end part 38 to the contact start part 39 with the secondary side switch 41.4 whose connection position is regulated by the gate pulses g and 1.
1' are regulated by the ends 41-b and 41'-, respectively, and the secondary fixed coil 42.4 of the rotating transformer
2' and the AC signal generator 43 are connected.

Along with this operation, an AC signal from the AC signal generator 43 is applied to the secondary fixed coils 42 and 42' of the rotary transformer as shown in FIG.
4'. The transmitted AC signals h' and l' of the primary rotating coils 44 and 44' are applied to the AC signal detector 45, and the connection position of the primary side switch 46°46' is changed to 46 by the action of the AC signal detector 45. -b
, 46'-b, and are applied to the AC signal rectifier 47 via the lead wire 48 at the timing shown at 0 in FIG. In the AC signal rectifier 47, the added AC signal o'l
As shown at p in FIG. 3, it is rectified, stabilized at a predetermined DC voltage vO, and +vcc of the recording and reproducing amplifiers 49 and 49'.

GNI) terminal. In ltm in FIG. 3, the secondary side switch 41.41' is 41-IL, 41'-& end side is the secondary side switch 46.46' is 46-IL.

46' - & indicates the timing at which the terminals are regulated and connected, respectively. Also, the rotating head 1.1' and the magnetic tape 3
The contact with 3 is also at the timing j2m in FIG. Signals can be recorded (or reproduced) on the magnetic tape 33. And record.

Since the regenerative amplifiers 49 and 49' reach the operating state with the applied DC voltage vO as described above, if the VTR is in the reproducing state, the regenerative signal from the rotary head 1°1' shown at H as shown in FIG. Individually amplified and connected to the primary side switch terminal 46-IL
, 46'-&, switches 4e, 4e: are added to the primary rotating coil 44, 44' of the rotating transformer, and are output to the corresponding secondary fixed coils 42, 42', and are connected to the secondary side switch. 41°41', switch terminal 41
-2L and 41'-2L to the subsequent signal processing circuit. Also, when the VTR is in the recording state, the recording signal goes through the switches 41 and 41', the rotary transformer, and the switches 46 and 46' to the recording and reproducing amplifiers 49 and 49'.
, amplified and applied to the rotary head 1.1', respectively.

Effects of the Invention As described above, according to the present invention, it is possible to completely eliminate the problems of the configuration in which power is supplied to the preamplification means through rotational contact between the electrode of the slip ring and the plan described in the conventional example. There is no need for a new rotating transformer for power supply, which contributes to downsizing of the rotating head device and improved reliability of the VTR.

Furthermore, similar effects can be obtained even when the present invention is applied to a high-speed rotary head device such as a high-definition TR or digital VTR.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram of an embodiment of the present invention, Fig. 2 is a sectional view of the rotary head device, Fig. 3 is a timing chart of each part of the same, and Fig. 4 is a sectional view of a conventional rotary head device. ,
FIG. 6 is a wiring diagram showing the flow of reproduction signals from the rotary head. 1,1'... Rotating head, 4... Rotating cylinder, 33... Magnetic tape, 34.35.
... tape guide, 36.36'... magnet, 37, 37', -18,. Rotating pulse detection head, 4Q...gate pulse generator, 41.41'...secondary side switch,
42゜42'...Secondary fixed coil of rotating transformer, 43...AC signal generator, 44.44'
・・・・・・Primary side rotating coil of rotating transformer, 46・
...AC signal detector, 47...AC signal rectifier, 49,49'...Record. Regenerative amplifier. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A rotating head non-contact area detection means for detecting a non-contact area between the wound magnetic tape and the rotating head as pulses synchronized with the rotation of the rotating head, an AC signal generator that generates an AC signal by energization, and a rotating head. A rotary transformer transmits signals between a primary rotary coil that rotates together with the secondary fixed coil that corresponds to the primary rotary coil, and a secondary fixed coil of the rotary transformer and the alternating current signal generator that are connected to the rotary head in a non-contact manner. secondary side switch means that is selectively connected in synchronization with the pulse of the area detection means and transmits the AC signal from the AC signal generator to the primary rotating coil of the rotary transformer; and connected to the rotating head; a recording/reproducing amplifier that performs predetermined signal processing; an alternating current signal rectifier that rectifies the input AC signal and applies its output to the power source of the recording/reproducing amplifier; A magnetic recording and reproducing apparatus characterized in that it comprises primary side switch means for detecting an AC signal from the AC signal generator and connecting the primary side rotating coil of the rotary transformer and the input of the AC signal rectifier. rotating head device.