JP2624100B2 - Electromagnetic conversion characteristics measurement device for magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring electromagnetic conversion characteristics of a magnetic head, and more particularly, to automatically adjusting a contact state between a magnetic head and a magnetic tape when measuring an electromagnetic conversion characteristic of a video magnetic head used in a VTR. The present invention relates to an electromagnetic conversion characteristic measuring device for a magnetic head.

[0002]

2. Description of the Related Art In general, a magnetic head for video (hereinafter, simply referred to as a magnetic head) used for a VTR has not only predetermined dimensions of each part with high accuracy but also different predetermined frequencies such as 0.5 MHz, 1 MHz and 3 MHz. Must have desired recording and reproduction characteristics, that is, satisfy the predetermined electromagnetic conversion characteristics.

[0003] As an apparatus for measuring the electromagnetic conversion characteristics of the magnetic head, there is, for example, a "magnetic head electromagnetic conversion characteristic measuring apparatus" disclosed in Japanese Patent Application Laid-Open No. 59-90227.

In the apparatus for measuring the electromagnetic conversion characteristics of a magnetic head, a measurer adjusts the relative positional relationship between a magnetic head and a magnetic tape, that is, adjusts the contact pressure between the two, by a measurer placed on an XY stage. This is performed by adjusting a contact pressure while moving a magnetic head or a magnetic tape, and monitoring a reproduction output signal from the magnetic head with an oscilloscope or the like.

FIG. 7 is a partial longitudinal side view of a conventional example of a magnetic head electromagnetic conversion characteristic measuring apparatus 1. In general, a rotary drum supporting mechanism 2 and a magnetic head holding mechanism 3 are arranged close to a base 4. It consists of an arrangement. Reference numeral 5 denotes a rotary drum having the same diameter as the drum of the VTR, rotatably supported by the rotary drum support mechanism 2, and rotated by a synchronous motor (not shown). In addition, on the peripheral surface of the rotating drum 5,
The magnetic tape 6 is wound on the same plane over substantially the entire circumference with the magnetic surface facing outward.

The magnetic head holding mechanism 3 generally has a configuration in which an XY stage 8 is provided on a lifting stage 7 and a magnetic head fixing holder 9 is provided on the XY stage 8. 10 is a Y-axis direction shift operation knob, 11 is an X-axis direction shift operation knob, 12 is a vertical movement shift operation knob, 13
Denotes a magnetic head to be measured, and 14 denotes a contact pin provided above the magnetic head 13.

Next, the electromagnetic conversion characteristic measuring device 1 having the above configuration
The operation and operation when measuring the electromagnetic conversion characteristics of the magnetic head 13 using the above will be described.

After the magnetic head 13 to be measured is fixed to the magnetic head fixing holder 9, the XY stage 8 is moved by manually operating the Y-axis direction shift operation knob 10 and the X-axis direction shift operation knob 11. Then, the magnetic head 13 is brought into contact with the magnetic tape 6 wound around the rotating drum 5 rotating at high speed. At this time, the configuration is such that the supply of the recording signal to the magnetic head 13 and the pickup of the reproduction output signal by the contact pin 14 are performed in synchronization with the rotation of the rotary drum 5. As a result, the magnetic head 13 repeatedly scans the same annular track along the longitudinal direction of the magnetic tape 6 so that the magnetic head 13 repeatedly scans the same track. The reproduction is sequentially performed, and the measurement of one point is completed by the reproduction output. Further, the elevation stage 7 is moved up and down by manually operating the up / down direction shift operation knob 12 to sequentially measure the other tracks in the same manner, and the magnetic head 13 completes the measurement by measuring the electromagnetic conversion characteristics at a plurality of predetermined points. I do.

[0009]

However, in the measurement by the conventional electromagnetic conversion characteristic measuring apparatus 1 described above, the optimum contact pressure between the magnetic head 13 and the magnetic tape 6 must be adjusted prior to the measurement.

That is, the measurer moves the magnetic head 13 arranged on the magnetic head fixing holder 9 on the XY stage 8 to the Y position.
Using the axial shift operation knob 10 and the X axis direction shift operation knob 11, the magnetic head 13 is brought into contact with the magnetic tape 6 wound around the rotating drum 5 rotating at a high speed to perform recording and reproduction. While monitoring the output signal with an oscilloscope (not shown), the Y-axis direction shift operation knob 10 and the X-axis direction shift operation knob 11 are further moved to XY.
Then, the contact pressure of the magnetic head 13 is adjusted so as to obtain the maximum reproduction output by fine movement in the direction, and thereafter, the above-described electromagnetic conversion characteristics are measured.

FIG. 8A shows a waveform of a reproduced output signal when the contact pressure between the magnetic head 13 and the magnetic tape 6 is small. FIG. 8B shows the waveform of the reproduced output signal when the contact pressure between the magnetic head 13 and the magnetic tape 6 is small. FIG. 7C is a diagram showing a waveform of the reproduced output signal when the contact pressure is large, and FIG. 7C is a diagram showing a waveform of the reproduced output signal when the contact pressure between the magnetic head 13 and the magnetic tape 6 is optimal. At the time of these measurements, the TIME / DIV of the oscilloscope is set such that all the reproduction output signals for one rotation of the rotating drum are displayed on the monitor screen.

As shown in these drawings, the contact pressure between the magnetic head 13 and the magnetic tape 6 has a great effect on the reproduction output value of the magnetic head 13, and therefore requires an adjustment operation and an accurate measurement. This is a very important task in doing. However, since these adjustments are performed only by the subjective judgment of the measurer, training of the measurer is required for accurate measurement, and the reproducibility of the measured data is poor. There were problems such as incompatibility of measurement data between users.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a signal of a predetermined frequency is recorded on a magnetic tape by a magnetic head, and the recorded signal is reproduced. In an apparatus for measuring the electromagnetic conversion characteristics of the magnetic head, a rotating drum rotating at a predetermined speed by winding the magnetic tape at least with the magnetic surface facing outward, and the rotating drum mounted on a table A rotary drum supporting mechanism including an XY table for moving the rotary drum in X and Y directions, and a plurality of magnetic head holding units for holding at least the magnetic heads are provided at predetermined positions on the index table. The tip of the head is mounted so as to protrude from the outer peripheral surface of the index table, and the magnetic head is sequentially measured by the rotation of the index table. And a magnetic head transport mechanism for transporting,
A video camera device provided above the magnetic head at a position adjacent to the measurement unit and having an image processing device therein; and a gap portion of the magnetic head is removed by the image processing device provided in the video camera device. Automatic adjusting means for measuring the length, controlling the electric XY table based on the measured data, and adjusting the contact pressure between the magnetic head and the magnetic tape to be optimal. An object of the present invention is to provide an electromagnetic conversion characteristic measuring device for a magnetic head.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The electromagnetic conversion characteristic measuring apparatus according to the present invention is characterized by an automatic adjusting means for adjusting the contact pressure between a magnetic head and a magnetic tape to be optimum before measuring the electromagnetic conversion characteristics of a magnetic head. Things.

FIG. 1 is a partially longitudinal side view showing a first embodiment of an electromagnetic conversion characteristic measuring apparatus 20 according to the present invention, FIG. 2 is a plan view of FIG. 1, and FIG.
3 is a signal system block diagram of the automatic adjustment means 40 of FIG.

An electromagnetic conversion characteristic measuring device 20 according to the present invention.
Generally includes a rotating drum support mechanism 21 and a magnetic head holding mechanism 22 which are arranged close to a base 23,
It is composed of

An embodiment of the electromagnetic conversion characteristic measuring apparatus 20 according to the present invention will be described below with reference to FIGS.

The rotating drum support mechanism 21 includes a rotating drum 24 wound around a magnetic tape 26 with its magnetic surface facing outward and rotating at a predetermined speed, and a rotating drum 24 rotating at a predetermined speed.
25 for rotatably supporting the drum, and a rotating drum 24
And an electric XY table 27 on which the motor unit 37 is mounted. The electric XY table 27 moves the rotating drum 24 mounted on the upper part by X-axis stepping motor 28 and Y-axis stepping motor 29 in the X and Y directions, and the magnetic tape 26 wound around the rotating drum 24 and the magnetic tape 26 described later. To be brought into contact with the magnetic head 35. As a result, the magnetic head 35 repeatedly scans the same annular track along the longitudinal direction of the magnetic tape 26 and relatively scans.

The magnetic head holding mechanism 22 has a magnetic head fixing holder 36 for holding a magnetic head 35.
a, 36b and the magnetic head fixing holders 36a, 36
Rotating mechanism unit 3 that rotates 180 ° intermittently with b placed on top
1 and a pre-recording amplifier box 32 in which amplifiers connected to the magnetic head 35 via the contact pins 33 are stored. This magnetic head holding mechanism 2
Reference numeral 2 denotes a magnetic head 35 to be measured.
2, for example, after being set on one of the magnetic head fixing holders 36b, the rotary mechanism section 31 is rotated by 180 ° by the rotary actuator 30 shown in FIG. 2, and the magnetic head 35 set on the magnetic head fixing holder 36b is rotated. Move to the 24 side. A recording amplifier (recording amplifier) 3 is provided above the magnetic head 35 moved to the rotating drum 24 side.
2a and a pre-amplifier (preamplifier) 32b are housed therein, and there is a pre-recording amplifier box 32 provided with contact pins 33 connected to these amplifiers and exposed to the outside. Then, the amplifier in the pre-recording amplifier box 32 and the magnetic head 35 are connected in a circuit via the contact pins 33. Reference numeral 38 denotes a switcher for appropriately switching between the recording amplifier 32a and the reproduction preamplifier 32b, and reference numeral 44 denotes a sweep generator for generating a signal of a predetermined frequency.

Further, the X-Y of the electric XY table 27 is adjusted so that the contact pressure between the magnetic head 35 and the magnetic tape 26 is optimized.
An automatic adjusting means 40 comprising, for example, a remote box 41 and a microcomputer 42 for controlling the axis stepping motor 28 and the Y-axis stepping motor 29 is provided.

The magnetic tape 26 and the magnetic head 3 which are features of the electromagnetic conversion characteristic measuring apparatus 20 of the present invention having the above-described structure.
The control method of the automatic adjusting means 40 for adjusting the contact of No. 5 will be described in detail with reference to FIGS.

The X-axis stepping motor 28 and the Y-axis stepping motor 29 of the electric XY table 27 are driven in the XY directions by controlling the automatic adjusting means 40 comprising the remote box 41 and the microcomputer 42 described above. As shown in FIG. 4, the contact pressure of the magnetic head 35 in contact with the magnetic tape 26 is stepwise (P0 to P6).
And the respective reproduction outputs at the respective positions are displayed on the screen of the spectrum analyzer 43.

FIG. 4 shows the spectrum analyzer 43.
FIG. 5 is a reproduction output diagram at each position where the contact pressure of the magnetic head 35 displayed on the screen is changed stepwise (P0 to P6), and a0 to a6 at the respective contact pressures (P0 to P6) are Shows a period during which information is erased and recorded on the magnetic tape 26 by the measured magnetic head 35,
Similarly, b0 to b6 indicate periods during which information is reproduced.

Magnetic head 35 in contact with magnetic tape 26
The direction in which the contact pressure increases is the positive direction, and the change in the contact pressure is Δ
X, and the contact pressure determined by the measurer is P3. First, the rotary drum 24 is moved by -3ΔX, and information is erased, recorded, and reproduced (a0, b0) at that position. The position at this time is the position of P0.

After erasing, recording, and reproducing information at the position P0, erasing, recording, and reproducing information are repeated at each position (P1 to P6) while the rotary drum 24 is moved stepwise at + ΔX steps. Do it. When this series of operations is completed, the measured data for each of the positions P0 to P6 is displayed on the screen of the spectrum analyzer 43 in FIG.
Is displayed as shown. The displayed data is taken into the microcomputer 42 to detect the position where the reproduction output becomes maximum, and the X-axis stepping motor 28 and the Y-axis stepping motor 29 of the electric XY table 27 are driven to move the rotary drum 24 to the position. Then, the automatic adjustment is completed.

After the measurement start switch is input by the operator, these adjustments are all automatically performed under the control of the microcomputer 42. Therefore, high-precision measurement not affected by the hit adjustment by the measurer can be realized.

Further, a second embodiment of the electromagnetic conversion characteristic measuring apparatus 50 according to the present invention will be described with reference to FIGS. 1, 3, 5 and 6.

FIG. 5 is a plan view showing a main part of an electromagnetic conversion characteristic measuring apparatus 50 according to a second embodiment of the present invention. The same parts as those in FIG. Specific description is omitted.

This electromagnetic conversion characteristic measuring device 50 is generally
It comprises a rotating drum support mechanism 21, a magnetic head transfer mechanism 53, and an automatic adjusting means 56 which are arranged close to the base.

The rotating drum supporting mechanism 21 is the same as the rotating drum supporting mechanism 21 of the electromagnetic conversion characteristic measuring device 20 described above, and has a magnetic tape 2 with its magnetic surface facing outward.
Drum 6 that is wound around the entire circumference and rotates at a predetermined speed, a cylinder 25 that rotatably supports the rotary drum 24, and a motor unit 37 that rotates the rotary drum 24
And an electric XY table 27 on which the motor unit 37 is mounted. The electric XY table 27 is rotated by an X-axis stepping motor 28 and a Y-axis stepping motor 29.
Is moved in the X and Y directions by the automatic adjusting means 56, and the magnetic tape 26 wound around the rotating drum 24 and the magnetic head 35
Contact. As a result, the magnetic head 35 repeatedly scans the same annular track along the longitudinal direction of the magnetic tape 26 and relatively scans.

Numeral 53 denotes a magnetic head transfer mechanism, which comprises a plurality of magnetic head holders 51 arranged at equal intervals and a circular index table 52 for holding the magnetic head 35. The magnetic head holding portion 51 is arranged so that a part thereof protrudes from the outer periphery, and the circular index table 52 is intermittently rotated in a direction indicated by an arrow by a motor (not shown).
5 are sequentially transferred to the measuring station B.

Reference numeral 56 denotes automatic adjusting means.
It comprises a video camera device 54 having an appropriate magnification provided above the magnetic head 35 of the standby station A adjacent to the measurement station B, and an image processing device 55.
When the gap position of the magnetic head 35 is measured using the video camera device 54 to measure the electromagnetic conversion characteristics of the magnetic head 35 in a mass production line or the like,
It will be extremely effective.

The electromagnetic conversion characteristic measuring device 5 having the above configuration
The automatic adjustment of the automatic adjustment means 56 for adjusting the contact between the magnetic tape 26 and the magnetic head 35, which is a feature of the automatic adjustment, will be described in detail below.

Assuming that the rotation direction of the circular index table 52 is a counterclockwise direction, the magnetic head 35 to be measured moves before the electromagnetic conversion characteristics are measured at the measuring station B.
It will pass through the waiting station A. Here, when the measurement of the magnetic head 35a is being performed at the measurement station B, the magnetic head 35b to be measured next has been moved to the standby station A and is fixed there. Then, at the standby position, the gap portion of the magnetic head 35b is photographed from above the magnetic head 35b by a video camera device 54 in which, for example, a CCD camera is arranged.

FIG. 6 is an enlarged view of the gap portion of the magnetic head 35b projected on the monitor screen by the CCD camera.

From the displayed monitor screen, a reference point P set inside or outside the screen using the image processing device 55 (set at the upper left corner of the monitor screen in FIG. 6).
And the gap position 35 of the projected magnetic head 35b.
The distance from b-1 is measured, and the distance data Xg and Yg are input to the microcomputer 42 shown in FIG. The microcomputer 42 rotates the circular index table 52 based on this signal to transfer the magnetic head 35b to the measuring station B, and based on the previously input data of Xg and Yg, the X-axis stepping motor 28 and Y The rotary drum 24 is moved by controlling the shaft stepping motor 29. After the movement, the adjustment is completed by performing the hit automatic adjustment described in the first embodiment, and the process proceeds to the measurement of a predetermined electromagnetic conversion characteristic. After the measurement is completed,
-X-axis stepping motor 28 of Y table 27 and Y
By driving the shaft stepping motor 29, the rotating drum 24
Is moved in the direction opposite to the direction at the time of measurement to be ready for the next measurement.

With this configuration, the present invention can fully automate the electromagnetic conversion characteristics of the magnetic head and measure the position of the gap tip 35b-1 of the magnetic head 53b using the video camera device 54. When measuring the electromagnetic conversion characteristics of a magnetic head in a mass production line, etc., it is possible to construct an extremely effective fully automatic electromagnetic conversion characteristic measurement system, and to measure without being affected by the skill of the measurer. This can reduce variation in data.

[0038]

As described above, according to the device of the present invention,
Adjustment of the contact pressure between the magnetic head and the magnetic tape can be fully automated without being affected by the skill of the measurer,
By using a video camera, the head length can be measured in advance and rough adjustment of each component can be performed, and then the optimal contact pressure between the magnetic head and the magnetic tape can be finely adjusted. The effect is that the speed can be increased.

[0039]

[Brief description of the drawings]

FIG. 1 is a first embodiment of an electromagnetic conversion characteristic measuring apparatus according to the present invention.
FIG.

FIG. 2 is a first embodiment of an electromagnetic conversion characteristic measuring apparatus according to the present invention.
FIG.

FIG. 3 is a signal block diagram of an automatic adjusting unit of the electromagnetic conversion characteristic measuring device according to the present invention.

FIG. 4 is a reproduction output diagram of the magnetic head displayed on the screen of the spectrum analyzer.

FIG. 5 is a second embodiment of the electromagnetic conversion characteristic measuring apparatus according to the present invention.
FIG.

FIG. 6 is an enlarged view of a gap portion of the magnetic head shown on a monitor screen.

FIG. 7 is a partially longitudinal side view of a conventional example of an electromagnetic conversion characteristic measuring device for a magnetic head.

FIG. 8A is a diagram showing a waveform of a reproduction output signal when a contact pressure between a magnetic head and a magnetic tape is small.

FIG. 8B is a diagram showing a waveform of a reproduction output signal when the contact pressure between the magnetic head and the magnetic tape is large.

FIG. 8C is a diagram showing a waveform of a reproduction output signal when the contact pressure between the magnetic head and the magnetic tape is optimal.

[Explanation of symbols]

 Reference Signs List 21 rotating drum support mechanism 24 rotating drum 26 magnetic tape 27 electric XY table 28 X-axis stepping motor 29 Y-axis stepping motor 31 magnetic head holding mechanism 35 magnetic head 36 magnetic head holding unit 40 automatic adjustment means 52 index table 53 magnetic head Transfer mechanism 54 video camera device 55 image processing device 56 automatic adjusting means

Claims (1)

(57) [Claims] An apparatus for recording a signal of a predetermined frequency on a magnetic tape by a magnetic head and measuring the electromagnetic conversion characteristics of the magnetic head by reproducing the recorded signal, wherein at least a magnetic surface is directed outward. A rotary drum support mechanism including a rotary drum that winds the magnetic tape around the entire circumference and rotates at a predetermined speed, and an XY table that moves the rotary drum placed on a table in X and Y directions. And mounting at least a plurality of magnetic head holding portions for holding the magnetic head at predetermined positions on the index table such that the tip of the magnetic head projects from the outer peripheral surface of the index table. A magnetic head transfer mechanism for sequentially transferring the magnetic head to the measurement unit by rotation of the magnetic head, and a magnetic head at a position adjacent to the measurement unit. A video camera device having an image processing device provided therein, which is provided above the head. The length of the gap portion of the magnetic head is measured by the image processing device provided in the video camera device. And an automatic adjusting means for controlling the electric XY table on the basis of the electric XY table and adjusting the contact pressure between the magnetic head and the magnetic tape to be optimal. measuring device.