JPH07105015B2 - How to adjust the height of the 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 a magnetic head height adjusting method used in a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art Since a fluid bearing does not have uneven rotation due to the precision of the bearing as compared with a conventional bearing, a VT
It has come to be widely used as a bearing for a cylinder of a magnetic recording / reproducing apparatus such as R. To adjust the track height of the head on the cylinder (the height of the head gap end with respect to the tape guide at a fixed position of the lower cylinder, TH in the enlarged view of FIG. 1), a spacer is conventionally provided between the cylinder and the head base. After making a rough adjustment by sandwiching and fixing it, the head base was pushed by the screw protruding from the cylinder.

[0003]

Generally, a fluid dynamic bearing used in a VTR or the like has a structure in which the shaft is supported by a dynamic pressure generated by the rotation of the shaft. do not become. Therefore, in the conventional method of adjusting the track height of the head with screws, first attach the upper cylinder to the lower cylinder and rotate at a regular number of revolutions, and emit the strobe light in synchronization with the rotating track height. Measure by a method such as observing still on a monitor. Next, the cylinder is stopped, the screw is rotated by a predetermined amount, the track height is adjusted to the target value, and the cylinder is rotated again to check the track height. If the target value is not met, this work needs to be repeated again, and if a large number of heads are mounted on the cylinder, it will take a very long time.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is a magnetic recording / reproducing apparatus having a rotating cylinder held by a fluid bearing, the head being mounted with the cylinder being rotated. The track height is adjusted by measuring the track height and irradiating a laser beam between the head attachment portion of the head base on which the head is mounted and the attachment portion to the cylinder.

[0005]

According to the method of the present invention, by irradiating the head base with laser light, the track height of the head can be adjusted without contact, so that measurement, adjustment and confirmation can be performed without stopping the rotation of the cylinder. , Can work efficiently in a very short time.

[0006]

EXAMPLE An example of the present invention will be described with reference to FIG. The upper cylinder 2 is fixed to the rotating shaft 5 of the lower cylinder 1. Although not shown, the rotary shaft 5 is connected to a motor and is fixed via a fluid bearing. The rotation of the fluid bearing generates a dynamic pressure to hold the upper cylinder in a proper position. The upper cylinder 2 rotates in the direction of arrow R, the strobe 6 emits light in synchronization with the rotation, and the image of the head 3 coming in front of the microscope 8 to which the television camera 7 is connected is displayed on the monitor 9. When the upper cylinder 2 rotates and the head 3 reaches the laser light irradiation position, the laser light 4
(FIG. 2), the fixing hole 12 for fixing the head base 11 to the cylinder and the attachment portion 15 for the head chip 13 are shown in FIG.
The laser light irradiating section 14 between them is irradiated. This laser light irradiation melts the surface of the head base, and due to the thermal expansion of the head base material, it deforms around the melted part during cooling,
The head base warps on the irradiation side. As a laser, for example, a YAG laser is used, the light is focused to 0.4 mmφ, and 1 J of energy per pulse is irradiated with a pulse width of 0.5 ms. Laser light is irradiated from the tip of a brass head base having a thickness of 1 mm and a width of 4 mm to a laser light irradiation unit 14 having a thickness of 3 mm to transform the irradiation side to about 0.5 μm per pulse.
The number of irradiation pulses is adjusted according to the difference between the head height and the target value to match the target value. Adjust the number of irradiations according to the first measured value, measure the head height after deforming to near the target value, weaken the pulse energy and irradiate the laser to finely adjust the height. It is possible to obtain a head that fits well. If the rotation speed of the cylinder is too fast and the laser irradiation area becomes too long, decrease the rotation speed to the minimum speed that allows stable rotation of the cylinder, or change the laser pulse width and irradiation area. It is adjustable. Even in the case of a head base material other than metal, the method of the present invention can be applied without any problem if the head base surface is melted by laser light irradiation.

[0007]

According to the present invention, since the track height of the head can be measured and the height can be adjusted while rotating the cylinder, a large number of heads can be used in a magnetic recording / reproducing apparatus having a cylinder held by a fluid bearing. Even in the case of a cylinder equipped with, the head height can be adjusted efficiently in a short time without stopping the cylinder. Further, since the cylinder can be measured and adjusted in a rotating state, distortion of the rotating shaft that occurs when the cylinder is fixed does not occur, and highly accurate height adjustment can be performed.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a track height adjusting method of the present invention.

FIG. 2 is a diagram showing a laser light irradiation portion of the present invention.

[Explanation of symbols]

 1 Lower Cylinder 2 Upper Cylinder 3 Head Base 4 Laser Light 5 Rotation Axis 6 Strobe 7 TV Camera 8 Microscope 9 Monitor 11 Head Base 12 Fixing Hole 13 Head Chip 14 Laser Light Irradiation Section 15 Sticking Section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Riki Moriwaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Koji Funami, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 56) References JP-A-62-159326 (JP, A)

Claims (1)

[Claims] 1. In a magnetic recording / reproducing apparatus having a rotating cylinder held by a fluid bearing, the track height of a head attached while the cylinder is rotated is measured, and a head based head on which the head is mounted is mounted. A method for adjusting the height of a magnetic head, wherein the track height is adjusted by irradiating a laser beam between the attachment part and the attachment part to the cylinder.