JPH0363956A - Rotary head type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To exactly detect the rotating phase of a head by detecting the rotating phase of a reflection panel, which is provided on a rotary drum, by a reflection type photointerrupter. CONSTITUTION:On the upper surface of an upper drum 10, a reflection panel 13 is provided to reflect light and the reflection panel 13 is provided with an interval at an angle theta deg. in a peripheral direction between from the fitting position of one head 12a. On the other hand, in the outer peripheral part of a lower drum 11, an arm 14 is projected on the upper surface side of the upper drum 10 and a reflection type photointerrupter 15 is provided so as to face to the rotating routine of the reflection panel 13 from the upper direction. When the reflection panel 13 comes over the lower position of the reflection type photointerrupter 15, the light to be projected from the reflection type photointerrupter 15 is reflected on the reflection panel 13 and a detection pulse corresponding to the passage of the reflection panel 13 is outputted. Thus, the rotating phase of the rotary drum is directly detected and the rotating phase of the head exactly is detected as well.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention records data on a magnetic tape by scanning a track extending in the width direction of a running magnetic tape with a head provided on a rotating drum. The present invention relates to a rotary head type magnetic recording and reproducing device that reproduces data from a rotary head.

In a conventional rotary head type magnetic recording/reproducing apparatus, it is necessary to accurately detect the period during which the head is in contact with the magnetic tape, and to record data on the magnetic tape within that period. Apart from this, in order to ensure compatibility between magnetic recording and reproducing devices, there is also a need to limit the scanning section of the head with respect to the magnetic tape track to a certain range.
Also from this point of view, it is necessary to accurately detect the rotational phase of the head.

In order to meet these demands, in a conventional rotary head type magnetic recording/reproducing device, a magnet 2 is attached to the outer periphery of the rotor 1 of the drum motor, as shown in a perspective view and a plan view in FIGS. 5 and 6, respectively. is installed, and a Hall element 5 is arranged on a printed wiring board 4 provided on a part of the stator 3 of the same drum motor, and the position of the rotating magnet 2 is detected by the Hall element 5, thereby rotating together with the rotor 1. The rotational phase of the head 7 to which the upper drum 6 is attached is detected.

Problems to be Solved by the Invention However, in the above-described conventional rotary head type magnetic recording and reproducing device, the magnet 2 is attached to the rotor 1 of the drum motor, which is connected to the upper drum 6 via a main shaft (not shown). Since the Hall element 5 that detects the magnet 2 is arranged on the printed wiring board 4 provided on a part of the stator 3 of the drum motor, it is easy to mechanically attach the magnet 2 and the Hall element 5 to the upper drum 6. The error increases due to the intervening members, and the above installation causes an error corresponding to the error in the output pulse from the head position detection circuit that determines the rotational phase of the head 7 based on the detection of the magnet 2 by the Hall element 5. .

That is, in the conventional example described above, instead of directly detecting the rotational phase of the head 7 attached to the upper drum 6,
Since the rotational phase of the head 7 is indirectly detected by detecting the rotational phase of the rotor 1 of the drum motor connected to the upper drum 6, the detection error increases accordingly.

Furthermore, since the position of the magnet 2 is detected using the Hall element 5, the pulse width of the detection pulse becomes wide, and from this point of view as well, it is difficult to accurately detect the rotational phase of the head 7. .

Therefore, in order to improve the above-mentioned error, in the conventional rotary head type magnetic recording/reproducing device, an adjustment circuit is added to the head position detection circuit to electrically correct the above-mentioned error, and a separately prepared standard playback device is added to the head position detection circuit. It was necessary to determine the above-mentioned error from the reproduced data using a commercial tape, and to adjust the output timing of the detection pulse output from the head position detection circuit by the amount of the error.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary head type magnetic recording/reproducing device that can accurately detect the rotational phase of a head without requiring an adjustment circuit for modifying the output timing of detection pulses.

Means for Solving the Problems The present invention includes a rotating drum provided with a head, and records data on the magnetic tape by scanning tracks extending in the width direction of the running magnetic tape with the head of the rotating drum.
Alternatively, in a rotating head type magnetic recording and reproducing device that reproduces data from a magnetic tape, a reflective plate is provided on the rotating drum, and a reflective photointerrupter is placed at a predetermined fixed position so as to face the rotation path of the reflective plate. This is a rotary head type magnetic recording and reproducing apparatus characterized in that the rotational phase of the head is detected based on the detection of a reflection plate by a reflection type photointerrupter.

Function According to the present invention, since the rotational position of the reflector provided directly on the rotating drum is detected by the reflective photointerrupter provided at a predetermined fixed position, the rotational phase of the rotating drum can be directly detected. Therefore, the rotational phase of the head attached to the rotating drum can be detected accurately.

Embodiment FIG. 1 is a front view showing the structure of a rotary cylinder 8 in a rotary head type magnetic recording/reproducing apparatus which is an embodiment of the present invention, and FIG. 2 is a plan view thereof.

In FIGS. 1 and 2, the rotating cylinder 8 includes a drum motor 9, an upper drum 10 as a rotating drum that is directly connected to the motor 9, and is rotationally driven.
The lower drum 11 is disposed coaxially with the upper drum 10 directly below the upper drum 10 along the axial direction.

Two heads 12a and 12b for scanning the magnetic tape are attached to the outer periphery of the upper drum 10 at an angle of 180° in the circumferential direction.

Further, a reflection plate 13 that reflects light is provided on a part of the upper surface of the upper drum 10. Here, as shown in FIG. 2, it is assumed that the upper drum 10 rotates in the clockwise direction indicated by the arrow R, and the reflector 13 is rotated clockwise from the mounting position of one head 12a by an angle θ° in the circumferential direction. They shall be located at separate locations.

On the other hand, on the outer periphery of the lower drum 11, an arm 14 that is integrated with the lower drum 11 is provided to protrude toward the upper surface side of the upper drum 10. Reflective photo interrupter 1 facing from
5 is provided.

FIG. 3 is an enlarged view showing the correspondence between the reflective photointerrupter 15 and the reflector 13 on the upper drum 10. 6 When the reflector 13 approaches the lower position of the reflective photointerrupter 15, Reflective photo interrupter 1
5 is reflected by the reflection plate 13, and the reflected light is incident on the reflection type 7 auto-interrupter 15, so that the light projected from the reflection type photointerrupter 15 is reflected by the reflection plate 13.
A detection pulse corresponding to the passage of is output.

FIG. 4 is a timing chart showing the rotational phase detection operation of the heads 12a and 12b in the above rotary head type magnetic recording/reproducing device. FIG. 4(2) shows the waveform of the recording/reproducing signal for switching the disks 12a, 12b between the recording operation state and the reproduction operation state.

Referring to the timing chart of FIG. 4, the rotational phase detection operation of the rotary head type magnetic recording/reproducing apparatus will be described below.

The upper drum 10 is connected to the reflective photointerrupter 15.
Each time it rotates, one detection pulse a shown in FIG. 4(1) is output. Assuming that the time required for the upper drum 10 to rotate once is T, the time TA required from the time the photo interrupter 15 outputs the detection pulse a until the head 12a passes the standby position of the 7-photo interrupter 15 is TA = Txθ/360...It is expressed as (1). Further, since the two heads 12a and 12b are arranged at an angle of 180° in the circumferential direction, the head 12a
After passing through the standby position of the photo interrupter 15,
Next, the other Herad 12b is 7 oto interrupter 15
The time T required for the vehicle to pass through the waiting position is as follows.

The standby position of the photo interrupter 15 is now the head 12.
If it corresponds to the scanning start position of one track on the magnetic tape by a and 12b, as shown in FIG. 4, a detection pulse a is output from the photointerrupter 15 and TAf& activates the head 12a. Set the recording/playback signal to high level, and
After the time required to scan a track has elapsed, it is set to low level.

(When the recording/playback signal is at a high level, the head 12
a, 12b>, so that recording/reproduction by the head 12a is performed accurately on the magnetic tape, and after the detection pulse a is output (
TA+T,)f&, the recording/reproducing signal is set to high level to activate the head 12b, and after the time required to scan one track has elapsed, the signal is set to low level to activate the head 121). will be performed accurately on the magnetic tape.

In addition, if the scanning start position of one track on the magnetic tape deviates from the standby position of the photointerrupter 15 by a predetermined rotation angle, the scan start position in FIG. By shifting the phase of the recording/reproducing signal shown in FIG. 1, the heads 12a and 12b can similarly accurately record and reproduce information on the magnetic tape.

The detection pulse a of the photointerrupter 15 shown in FIG. This can be made sufficiently smaller than the time T required for one rotation.

Furthermore, since the reflecting plate 13 can be made sufficiently thin, the presence of the reflecting plate 13 will not make the rotation of the upper drum 10 unstable. Since the positional accuracy can be set to drum processing accuracy (μm order), the above-mentioned head rotation phase detection operation can be performed more accurately.

Effects of the Invention As described above, according to the rotary head type magnetic recording/reproducing device of the present invention, a reflector is provided on the rotating drum attached to the head, and the reflector is provided at a fixed position where the rotational phase of the reflector is determined in advance. Since the rotational phase of the head is detected by a reflective photointerrupter, there is no error in installation. The rotational phase of the head can be detected accurately.

[Brief explanation of drawings]

Fig. 1 is a front view showing the configuration of a rotating cylinder in a rotating head type recording/reproducing device which is an embodiment of the present invention, Fig. 2 is a plan view thereof, and Fig. 3 is a reflective photointerrupter and a reflection type in the rotating cylinder. FIG. 4 is a timing chart showing the rotational phase detection operation of the head; FIG. 5 is a perspective view showing the configuration of a rotating cylinder in a conventional rotating head magnetic recording/reproducing device; FIG. 6 is an explanatory diagram showing the positional relationship with the plate; The figure is a plan view of the rotating cylinder. 10... Upper drum, ■1... Lower drum, 12a, 1
2b...Head, 13...Reflector, 15...Reflection type photo interrupter

Claims (1)

[Scope of Claims] A rotating drum equipped with a head is provided, and the head of the rotating drum scans a track extending in the width direction of a running magnetic tape to record data on the magnetic tape or to read data from the magnetic tape. In a rotary head type magnetic recording/reproducing device designed for reproduction, a reflective plate is provided on a rotating drum, a reflective photointerrupter is provided at a predetermined fixed position so as to face the rotation path of the reflective plate, and the reflective photointerrupter is installed at a predetermined fixed position. 1. A rotary head type magnetic recording and reproducing device, characterized in that the rotational phase of the head is detected based on the detection of a reflection plate by a rotary head.