JPH04132009A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To fix the displacement of a magnetic head so as to be constant at the time of recording, and to obtain a good recorded track by controlling a magnetic head driving device by the detection signal of a magnetic sensor. CONSTITUTION:A magnet 32 is stuck with adhesives at a position between the magnetic head 7b on a supporting piece 7c projecting outward beyond the outer peripheral surface of a magnetic head driving part 7a and the outer peripheral surface of the magnetic head driving part 7a, and it is made to generate magnetic flux toward a direction parallel with a rotating shaft 3. Then, a Hall element 33 as the magnetic sensor for detecting the position of the magnetic head 7b is arranged at the position on a rotary drum 5 where the magnetic flux of the magnet 32 can be detected. Thus, the position of the magnetic head 7b can be detected by the magnetic sensor 33, and the displacement of the magnetic head 7b can be controlled by its detection information, and the displacement of the magnetic head can be fixed so as to be constant at the time of the recording, and the good recorded track can be obtained.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a magnetic recording and reproducing apparatus equipped with a rotating head assembly, such as a video tape recorder, a digital audio recorder, and the like.

[Conventional technology]

FIG. 6 is a perspective view of a conventional rotating drum shown in, for example, Japanese Patent Laid-Open No. 63-173219, FIG. 7 is a vertical cross-sectional view of the vicinity of the magnetic head drive device, and FIG. 8 is a vertical cross-section of the vicinity of the fixed head. 9 is a bottom view of the rotating drum seen from arrow IX-IX in FIG. 7. In the figure, (1) is a fixed drum, and (2) is a bearing attached to this fixed drum (1). , (3) indicates that a rotating shaft (4) that is supported by this bearing (2) and rotates is a pedestal fitted to one end of this rotating shaft (3), and (5) indicates that a screw (6) is attached to this pedestal (4). ) is a rotating drum mounted using a (7) As shown in Fig. 7, the rotary drum (5) is attached to the
A pair of magnetic head drive devices (hereinafter referred to as movable heads) installed at 0° opposing positions, protruding outward from the outer peripheral surfaces of the magnetic head drive section (7a) and the magnetic bed drive section (7a), and A support piece (7c) that can reciprocate on the rotating shaft (3), and a magnetic head (7c) fixed to the tip of the support piece (7c).
b). (8) is attached to the rotating drum (5) using screws (50) as shown in FIG.
A pair of fixed heads are mounted at 0 degrees opposite positions, and are composed of a magnetic head mount (8a) and a magnetic head (8b) fixed to the tip thereof. Furthermore, as can be understood from Fig. 6, the fixed head (8) and the movable head (7)
are separated from each other by 90°. (9) is the lower transformer (10) attached to the fixed drum (1), the upper transformer is attached to the pedestal (4), (11) is the wiring board attached to the rotating drum (5), and (12) is the This is a non-rotating contact for supplying control current to the magnetic head drive section (7a). (13) is a rotating electrode (
14) are magnetic head drive wires (7b) and (8b) electrically connected from this electrode (13) to the magnetic head drive unit (7a) via the terminal (15) and the wiring board (11).
) is a magnetic head attached to a magnetic head drive unit (7a) and a magnetic head mount (8a). These magnetic heads (7b) and (8b) are terminals (1
7), is electrically connected to the upper transformer (10) via the wiring board (11) and the terminal (15). (18) is a recess provided in a part of the rotating drum (5) to accommodate the magnetic head drive unit (7a), and is a recess provided in a part of the rotating drum (5) to accommodate the magnetic head drive unit (7a).
a) It is formed larger. (19) is a position adjustment hole for adjusting the position of the magnetic head (7b), and (2o) is a magnetic tape that comes into sliding contact with the magnetic head (7b). Figures 10, 11, and 12 show the head drive section (
7a) in more detail; in each figure, (21
) is made of a magnetic material and the first yoke (22) is a columnar first permanent magnet fixed to this first yoke (21).
) has a convex portion (23b) on a part of its inner periphery and is attached to the first yoke (21), and is made of a magnetic material, and (24) is attached to this second yoke (23). a third yoke of magnetic material attached (25);
(26) is a columnar second permanent magnet fixed to the third yoke (24) with the same magnetic poles as the first permanent magnet (22) facing each other; It is a pole piece made of a magnetic material that is located between the permanent magnets (22) and fixed to either one of them. (27) is a leaf spring made of a thin non-magnetic material, which is sandwiched between the first yoke (21) and the second yoke (23), and is provided on the first yoke (21) and the second yoke (23). It has a support piece (7C) that protrudes outward through the windows (21a) and (23a), and has a magnetic head (7C) at its tip.
b) is fixed. A leaf spring (28) is made of a thin non-magnetic material and is held between the second yoke (23) and the third yoke (24). (29) is a board (27)
, (28), and (30
) has an inner circumference of the first permanent magnet (22) and the second permanent magnet (25).
) and the outer periphery of the pole piece (26).
The bobbin (31) is fixed to the fixing member (29) with adhesive at the position having the position F).
) is a coil consisting of a wire with a sheath wound around it.
An annular gap (G) is provided over the entire circumference between the second yoke (23) and the convex portion (23b). Next, before explaining the overall operation of the above structure, the operation of the movable head (7) will be explained using FIG. 11. First, the first permanent magnet (22) is a pole piece (26),
A magnetic flux (D) is generated by a closed magnetic path created by the second yoke (23) and the first yoke (21). Similarly, the second permanent magnet (25) is connected to the pole piece (26).
, a closed magnetic path formed by the second yoke (23) and the third yoke (24) generates a magnetic flux (E) in the opposite direction to the magnetic flux (D). Both the magnetic flux (D) and the magnetic flux (E) generated in this way cross the annular gaps (F) and (G) in the same direction, and the coil (31) is connected to the first permanent magnet (22) and the second permanent magnet. (
25) is crossed by the total magnetic flux. In this state, when current is passed through the coil (31) from the contact (12) through the electrode (13) and the terminal (14), the coil (31), bobbin (30), and magnetic head (7b) become one body. and move vertically and parallelly in a straight line. Next, the overall operation will be explained. First, when recording a signal on the magnetic chip (20), the recorded signal is transmitted from the outside of the drum to the lower transformer (9) and the upper transformer (10).
, terminal (15), wiring board (11), terminal (
17) is transmitted to the magnetic head (8b) of the fixed head (8) and recorded on the magnetic tape (2o). Next, when reproducing the signal on the magnetic tape (20), the reproduced signal is obtained by tracing the signal recording trace (track) on the tape with the magnetic head (8b).
The signal travels in the opposite direction along the transmission path during recording and is transmitted to the outside of the drum. The above is an explanation of the recording and reproducing operation in the normal mode. However, when performing special reproduction, that is, reproducing the magnetic tape (20) at several times the speed of recording and reproducing, the operation is performed by the movable head (7). It will be done. In other words, the movable head (
7) is used only during special playback (several speed playback) and accurately traces the track recorded by the fixed head (8) by swinging it in the tape width direction. To explain this special playback in more detail, the fixed head (8
) to perform special reproduction of the magnetic recording traces (tracks) recorded on the magnetic tape (20), this operation is performed using a fixed head (8
), the trace locus of the fixed head (8) crosses the track on the magnetic head (20), causing a constriction in the reproduced signal, but in the case of a movable head (7), the rotation of the rotating drum (5) A substantially triangular drive current synchronized with the period is transmitted to the movable head (7) via the contact (12), electrode (13), wiring board (11) and terminal (14) to drive the magnetic head (7b). By swinging the tape in the width direction,
The conventional operation explanation is that a reproduced signal without constriction is obtained and a seamless continuous picture is obtained on the screen.
Normal mode reproduction can be performed with the movable head (7) using the conventional structure. That is, the movable head (7
) can be used to control the head drive current based on the error signal read by the head (7) to make the movable head (7) follow the recording track. However, when recording with the conventional structure, there are problems as described below. That is, FIG. 13 is a diagram showing the relationship between the drive current applied to the movable head (7) and displacement. As shown in this figure, the two have a hysteresis relationship, and the head drive current is Even if the movable head (7) is kept constant, the position of the movable head (7) is not uniquely determined. Therefore, as shown in FIG. The recording track (T) overlaps with the adjacent track by the dimension (α) [Problem to be solved by the invention] A conventional magnetic recording/reproducing device is configured as described above, and the movable head Since there is hysteresis between the drive current and the displacement, when recording signals on a magnetic tape, the magnetic head does not move to a fixed position,
80' A height difference (step) occurred between the two opposing magnetic heads, and as a result, the recording tracks overlapped with each other, making it impossible to obtain good recording tracks. In other words, there was a problem in that this movable head could not be used as a recording head. Note that Japanese Patent Publication No. 60-217516 discloses that the position of the movable head is accurately controlled by detecting the position of the movable head and controlling the drive current supplied to the movable head based on the detection signal. has been done. However, this is for accurately tracing recorded tracks, and there is no teaching that this movable head is also used for recording. Therefore, even if a movable head can be used for playback in normal mode, a fixed head is required for recording, so both a movable head and a fixed head are required, and a large number of heads are installed, resulting in high cost. was there. This invention was made in order to solve the above-mentioned problems. It enables normal mode recording with a movable head, and allows normal mode recording, playback, and special playback using only this movable head, and increases the number of heads. The purpose is to obtain less expensive equipment. [Means for Solving the Problems] A magnetic recording and reproducing device according to the present invention includes a magnetic head drive unit housed in a rotating drum, a magnetic head disposed at the tip of a support piece projecting outward from the outer peripheral surface of the magnetic head drive unit, and a magnetic head drive unit housed in a rotating drum. A magnet is arranged at a position between the magnetic head on the support piece and the outer circumferential surface of the magnetic head drive part of the magnetic head drive device configured by,
A magnetic sensor such as a Hall element is arranged at a position on the rotating drum that can detect the magnetic flux of the magnet, and the magnetic head is configured to control the position of the magnetic head based on the detection signal of this magnetic sensor. It can be used not only for recording purposes but also for recording purposes. [Function] According to the present invention, the position of the magnetic head is detected by a magnetic sensor, and the displacement of the magnetic head is controlled based on the detected information, so that the displacement of the magnetic head can be fixed at a constant level during recording, and a good result can be obtained. It is possible to obtain recording tracks. [Embodiment] An embodiment of the present invention will be described below with reference to the drawings. 1, 2, and 3 show a magnetic recording/reproducing device according to an embodiment of the present invention.To describe only the differences from the conventional example, (32) is a magnet, and the magnetic head is A support piece (7C) protrudes outward from the outer peripheral surface of the drive part (7a).
) on the magnetic head (7b) and the magnetic head drive section (7a)
It is fixed with adhesive at a position between the outer peripheral surface and generates magnetic flux in a direction parallel to the rotation axis (3). (33
) is a Hall element as a magnetic sensor that detects the position of the magnetic head (7b), and this magnetic sensor (33
) is a rotating drum (
5) It is placed in the upper position. Further, as shown in FIG. 5, a sensor amplifier (33C) for amplifying the output of the magnetic sensor (33), a reference voltage generator (33b),
It has a subtracter (33d) and a driver (34) that drives the movable head (7), and the sensor amplifier (3
3c), reference voltage generator (33b), subtracter (33d)
), the control section (35) is configured.Next, the operation of the above configuration will be explained. As shown in Figure 4, the magnetic sensor (33) can detect voltage according to the strength of the magnetic field (amount of magnetic flux), and exhibits approximately S-shaped characteristics (the north pole and the south pole are In other words, if used within the range where linearity of this characteristic can be ensured, the voltage changes linearly depending on the facing distance with the magnet, so the magnetic head (
7b), the position of which can be detected by the magnet (32) fixed on the support piece (27a) of the same magnetic head drive unit (7a), and the relationship between the output voltage and the position of the magnetic head (7b). becomes a straight line. Now, when recording information on a magnetic tape with the magnetic recording/reproducing apparatus of the present invention, as shown in FIG.
), the reference voltage generator (33b) generates a voltage (reference voltage) equivalent to the output of the magnetic sensor (33) at the height when the magnetic head (7b) enters according to the specifications, and The voltage output from the magnetic sensor (that is, the sensor amplifier (33c)) and the subtracter (33c)
d), calculate the difference, and move the magnetic head (7b) of the movable head (7) via the driver (34) so that the difference disappears, thereby moving the magnetic head to the standard position. (7b) is displaced and remains in that position. By performing such an operation in each movable head (7), it is possible to eliminate the level difference between channels during recording. In the above embodiments, a Hall element was used as the magnetic sensor. However, even if the magnetic sensor is a magnetoresistive element whose resistance value changes depending on the amount of magnetic flux, the above embodiments may also be used. A similar effect can be achieved.6 In addition, in the embodiment of the present invention, a movable head driver and a sensor amplifier are provided inside the rotating drum, but at least it is possible to provide only the sensor amplifier inside the rotating drum. Since a system resistant to external disturbances can be constructed in the transmission path after the sensor amplifier, the movable head driver may be provided outside the rotating drum. Moreover, conversely, the reference voltage generator and the subtracter may also be provided on the rotating drum. [Effects of the Invention] As described above, according to the present invention, a magnet is disposed on the support piece of the magnetic head drive unit, a magnetic sensor is disposed on the rotating drum facing the magnet, and the magnetic sensor detects the magnet. The magnetic head drive device is controlled by signals, and the displacement of the magnetic head can be fixed at a constant level when recording.
Since a good recording track can be obtained, an inexpensive device with a small number of heads that can perform normal mode recording, reproduction, and special reproduction using only a movable head can be obtained. Furthermore, by providing the sensor amplifier of the magnetic sensor inside the rotating drum, a system that is resistant to external disturbances (such as noise) can be constructed in the transmission line that transmits the output of the sensor amplifier to the outside of the drum.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a magnetic recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view showing the rotary drum of FIG. 1 inverted and with the movable head removed, and FIG. 1
FIG. 4 is a diagram showing the relationship between the magnetic field strength (amount of magnetic flux) and the output voltage of the magnetic sensor used in the present invention, and FIG. 5 is a diagram showing the relationship between the output voltage and the magnetic sensor used in the present invention. A diagram illustrating a path for feeding back signals obtained from a magnetic sensor to a magnetic head drive unit. FIG. 6 is a perspective view of a conventional rotating drum viewed from above. FIG. 7 is a conventional diagram having the rotating drum of FIG. 6. FIG. 8 is a sectional view of the conventional magnetic recording and reproducing device having the rotating drum shown in FIG. 6, taken from another side, and FIG. 9 is a view taken along the line IX-IX in FIG. 7. , 10th
The figure is an enlarged plan view of the movable head in Figure 9, and Figure 11 is an enlarged plan view of the movable head in Figure 9.
Figure 0 is a sectional view, Figure 12 is a side view of Figure 11, Figure 13 is a side view.
This figure shows the hysteresis characteristics of the magnetic head drive current and displacement in a conventional example, and FIG. 14 shows a track when recording is performed by a conventional movable head. In the figure, (1) is a fixed drum, (5) is a rotating drum, (7a) is a magnetic head drive unit, (7b) is a magnetic head, (20) is a magnetic tape, (7c) is a support piece, (32)
is a magnet, (33) is a magnetic sensor, and (35) is a control unit. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Patent Attorney Masu Oiwa Diagram Derminal Diagram Diagram 1? Figure 13 G & ← 0 on the side of the tape

Claims (2)

[Claims] (1) A magnetic head drive device consisting of a magnetic head drive section housed in a rotating drum and a magnetic head disposed at the tip of a support piece that protrudes outward from the outer peripheral surface of the magnetic head drive section; A magnetic recording and reproducing apparatus is provided with a fixed drum that is rotatably supported through a magnet, and a magnet is fixed on the support piece, and a magnetic sensor is arranged at a position on the rotating drum that can detect the magnetic flux of this magnet. A magnetic recording/reproducing device comprising: a control unit that controls the magnetic head drive device based on a detection signal from a sensor. (2) The magnetic recording and reproducing apparatus according to claim 1, further comprising a sensor amplifier provided inside the rotating drum for amplifying the detection signal of the magnetic sensor.