JPH04252414A - Method for adjusting height of magnetic head - Google Patents

Abstract

PURPOSE:To offer a method to adjust efficiently and with high accuracy the track height of the magnetic head on a rotary cylinder for which a fluid bearing is used. CONSTITUTION:In synchronizing with an upper cylinder 2 which rotates via the fluid bearing, a light beam is emitted by a stroboscope 6, the image of the head 3 is displayed on a monitor 9, and the height of the track is measured. When the head 3 comes to a position to be irradiated by a laser beam, the position between the hole for fixing the base of the head to the cylinder and a part where the chip of the head is glued on is irradiated by the laser beam 4. As the surface of the base of the head irradiated by the laser beam is melted, deformed in shrinkage, and deformed to the side of laser beam irradiation, it is irradiated by the laser as many times as required. After the height of the head, which can not be measured when the cylinder is at halt, is measured while the cylinder is rotating the adjustment of the height is performed continuously without touching in short time and with high accuracy.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the height of a magnetic head used in a magnetic recording/reproducing apparatus.

0002

[Prior Art] Compared to conventional bearings, hydrodynamic bearings do not cause uneven rotation due to the precision of the bearings, so VT
It has come to be widely used as a cylinder bearing for magnetic recording and reproducing devices such as R. Adjustment of the track height of the head on the cylinder (height of the end of the head gap relative to the tape guide at a determined position on the lower cylinder, TH in the enlarged view of Figure 1) is conventionally done by inserting a spacer between the cylinder and the head base. After making a rough adjustment and fixing it, the head base was pushed using a screw protruding from the cylinder.

0003

[Problem to be Solved by the Invention] Fluid bearings, which are generally used in VTRs, etc., have a structure that supports the shaft by the 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 using screws, the upper cylinder is first attached to the lower cylinder and rotated at the regular rotation speed, and the rotating track height is synchronized with the rotation to emit a strobe and then Measure by standing still and observing on a monitor. Next, with the cylinder stationary, turn the screw a predetermined amount to adjust the track height to the target value, then rotate the cylinder again and check the track height. If the target value is not met, it is necessary to repeat this operation again, and if a large number of heads are mounted on the cylinder, the operation takes a very long time.

0004

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a magnetic recording/reproducing device having a rotating cylinder held by a fluid bearing. The track height is adjusted by measuring the track height of the head base on which the head is mounted, and irradiating the space between the head attaching part of the head base on which the head is mounted and the attachment part to the cylinder with a laser beam.

[0005]

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

[0006]

[Embodiment] An embodiment of the present invention will be described with reference to (FIG. 1). The upper cylinder 2 is fixed to the rotating shaft 5 of the lower cylinder 1. Although not shown, the rotating shaft 5 is connected to a motor and fixed via a fluid bearing. The fluid bearing rotates to generate dynamic pressure and holds the upper cylinder in its normal position. The upper cylinder 2 rotates in the direction of arrow R, and in synchronization with the rotation, the strobe 6 emits light and the television camera 7
The image of the head 3 in front of the microscope 8 connected to the head 3 is displayed on the monitor 9. When the upper cylinder 2 rotates and the head 3 comes to the laser beam irradiation position, the laser beam 4 is directed through the fixing hole 12 of the head base 11 to the cylinder and the attachment part of the head chip 13, as shown in FIG. The laser beam is irradiated onto the laser beam irradiation section 14 between 15 and 15. The surface of the head base melts due to this laser beam irradiation, and due to the thermal expansion of the head base material, it deforms around the melted portion during cooling, causing the head base to warp toward the irradiation side. For example, Y as a laser
Using an AG laser, the light is narrowed to 0.4 mmφ and irradiated with energy of 1 J per pulse with a pulse width of 0.5 ms. A laser beam is irradiated from the tip of a brass head base with a thickness of 1 mm and a width of 4 mm to a 3 mm laser beam irradiation part 14, and the head base is deformed to the irradiation side by 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 initial measurement value, measure the head height after the head has deformed to near the target value, and irradiate with a weaker pulse energy to finely adjust the height. You can get a head that matches the size. In addition, if the rotation speed of the cylinder is too fast and the laser irradiation area becomes too long, reduce the rotation speed to the minimum speed that allows stable rotation of the cylinder, or change the laser pulse width and irradiation area. Adjustable. Note that 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 beam irradiation.

[0007]

According to the present invention, it is possible to measure the track height of the head and adjust the height while rotating the cylinder, so that it is possible to measure the track height of the head and adjust the height. Even if the cylinder is equipped with a cylinder, the head height can be adjusted quickly and efficiently without stopping the cylinder. Furthermore, since the cylinder can be measured and adjusted while rotating, there is no distortion of the rotating shaft that occurs when the cylinder is fixed, and height adjustment can be performed with high precision.

[Brief explanation of the drawing]

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

[Figure 2] Diagram showing the laser beam irradiation site 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 part 15 Sticking part

Claims (1)

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