JPH0645929Y2 - Polygon mirror drive - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polygon mirror driving device, and more particularly, to a structure for correcting the balance of a polygon driving rotating body in which a polygon mirror that rotates at a high speed is integrally fixed. is there.

[Prior art]

In a polygon mirror driving device (polygon scanner) that rotates a polygon mirror at a high speed, a highly accurate balance of the polygon driving rotating body is required, and therefore the balance is corrected. The methods for this balance correction are roughly classified into two methods: addition correction and deletion correction.

The latter deletion correction adjusts the balance by drilling with a drill, etc., but it has the problem that positioning of the drill is difficult, and the position of the drill tends to be slippery or bent and the position tends to be misaligned. Further, there is a problem that the polygon mirror is easily soiled by chips and the like.

Therefore, in consideration of dirt on the mirror (mirror surface), balance correction is generally performed by the former additional correction method. This additional correction method includes a method for adjusting the balance by adding a screw as shown in FIG. 8 and a method for adding the adjusting weight with adhesiveness as shown in FIGS. 9 and 10 for adjusting the balance. It was taken before.

That is, in the configuration shown in FIG. 8, a plurality of screw holes 53 are radially formed in advance from a part of the polygon driving rotary body 50 integrally fixed with the polygon mirror 51, for example, from the outer peripheral surface of the mirror mounting disk 52 toward the center. The holes were drilled, and screws 54 were selectively added to and screwed into the screw holes 53 to correct the balance.
In FIG. 8, 55 is a rotary shaft, 56 is a magnet,
57 is a drive coil, and 58 is an outer housing.

In the configuration shown in FIGS. 9 and 10, the polygon mirror 61
Part of the polygon drive rotor 60 that is integrally fixed to the main rotor 62, for example, a weight injection groove (or hole) 63 formed on the upper surface of the main rotor 62, and a correction weight 64 with selective adhesiveness is added to balance. I was making corrections. This modified weight 64
A commercially available two-component mixed adhesive weight was used, and it was designed to be cured after filling. In FIG. 9, 65 is a rotary shaft, 66 is a magnet, 67 is a drive coil, and 68 is an outer casing.

By the way, in a high-speed polygon mirror driving device using an air bearing or the like, a permissible unbalanced mass is required to be a very small value of the order of several milligrams (at a correction radius of about 20 mm), and the accuracy and resolution of measurement are required. In order to raise the speed, it is necessary to bring the measured rotation speed at the time of balance correction as close as possible to the actually used rotation speed and perform the rotation at a high speed of 20,000 rpm.

However, the number of screw holes 53 must be increased to 20 to 30 in order to apply the method shown in FIG. 8 to a high-speed polygon rotation type using an air bearing or the like and correct the balance accurately. There was a problem that the screw hole processing cost was very high, leading to cost up.

Further, in the method shown in the ninth and tenth figures, the correction weight 64 may fly if the balance is checked at a high speed before the correction weight 64 having adhesiveness is cured. There was a problem that the workability of correcting the balance was poor because the confirmation test had to be waited for about 8 to 10 hours before the curing.

〔Purpose〕

Therefore, the technical problem to be solved by the present invention is to solve the problems of the above-mentioned conventional technology, and the purpose thereof is to reduce the processing cost, improve the workability for the balance correction, and reduce the cost. It is to provide a polygon mirror driving device having a balance correction structure capable of achieving the above.

〔Constitution〕

In order to achieve the above object, the polygon mirror driving device of the present invention is provided with a plurality of punch marks for guiding a balance correction punching process, which are located on the same circumference, on a part of a polygon driving rotating body to which a polygon mirror is integrally fixed. Is formed in the thrust direction.

Since the present invention is as described above, the punch mark can be used as a guide to perform drilling with a drill, etc.
The drill will not be displaced. That is, it is possible to clearly understand what number of punch marks from the reference point should be drilled and cut corrected, and it is only necessary to determine the drill depth based on the case study data in advance, so accurate balance correction can be performed. You can do it quickly. Further, since the punch mark is formed in the thrust direction, the punch mark can be machined at the same time, and the machining cost can be remarkably reduced as compared with the formation of the screw hole.
In addition, it is not necessary to wait for confirmation of the balance correction until the adhesive is cured as in the case of using the adhesive correction weight, and the balance correction can be confirmed immediately.

By using a suction (suction) jig in combination with the cutting powder when correcting the drilling with a drill or the like, adhesion of the cutting powder to the mirror surface can be easily avoided.

The present invention will be described below with reference to the embodiments shown in FIGS.

FIG. 1 shows a high-speed drive (for example, 2 to 4) using a dynamic pressure air bearing.
FIG. 3 is a sectional front view showing a polygon mirror driving device of 10,000 rpm. In the figure, reference numeral 1 denotes a case body, which includes a bottom plate portion 2, a cylindrical body portion 3, and an upper plate portion 4. Reference numeral 5 denotes a shaft body whose bottom end is fitted and fixed to the bottom plate portion 2, and a groove 6 for generating a dynamic pressure having a known shape is formed on the outer peripheral surface of the shaft body 5,
The outer peripheral surface (radial bearing outer peripheral surface) and a later-described sleeve having an inner peripheral surface (radial bearing inner peripheral surface) maintaining a minute gap cooperate with each other to form a dynamic pressure radial bearing. Reference numeral 7 denotes a ring-shaped permanent magnet attached to the upper portion of the shaft body 5.

Reference numeral 8 denotes a polygon driven rotating body, as shown in FIGS. 2 to 4, a sleeve 9, a polygon mirror 10, an upper balance ring 11, a cap 13 to which a ring-shaped permanent magnet 12 is attached, a magnet 14 for a motor, The lower balance ring 15 is said to be integrally fixed. The inner peripheral surface of the sleeve 9 is precision-finished as a radial bearing inner peripheral surface that maintains a small distance from the outer periphery of the shaft body 5 as described above. 9a
Is a mirror receiving seat integrally formed with the sleeve 9, on which a polygon mirror 10 is placed, and the polygon mirror 10 is fixed to the mirror receiving seat 9a with a screw 16 through the upper balance ring 11 which also serves as a mirror retainer. Has been done. Further, the cap 13 is fitted into the upper end of the sleeve 16 and fixed with an adhesive, and the macnet 14 and the lower balance ring 15 are fitted from the lower end side of the sleeve 16 and fixed with an adhesive. .

Reference numeral 17 denotes a ring-shaped permanent magnet fixed to the upper plate portion via a mounting body 18, and the permanent magnet 17 and the permanent magnets 7, 12
Thus, a permanent magnet repulsive thrust bearing for supporting the polygon rotary drive body 8 is configured. That is, the permanent magnets 12 of the polygon driving rotor 8 receive repulsive forces from the upper and lower fixed permanent magnets 17, 17, respectively, and when the pushing down and pushing up repulsive forces are balanced, the polygon driving rotor 8 is moved. Is being levitated and held.

Reference numeral 19 is a drive coil fixed to the cylindrical portion 3, and constitutes a brushless motor together with the magnet 14.
The rotation position and speed of the rotor are detected by a hall element (not shown), and the polygon drive rotor 8 is rotated at a high speed by a known control circuit.

FIG. 2 is a perspective view (overhead view) looking down on the polygon driving rotary body 8, and FIG. 5 is a plan view of the upper balance ring 11, and as shown in the respective figures, the upper balance ring 11 is shown. On the upper surface, a plurality of punch marks 20 located on the same circumference are engraved simultaneously from the thrust direction. Further, FIG. 3 is a perspective view (elevation view) looking up at the polygon drive rotating body 8, and FIG. 6 is a bottom view of the lower balance ring 15. As shown in the respective drawings, the lower side is shown. A plurality of punch marks 20 located on the same circumference are also engraved on the lower surface of the balance ring 15 from the thrust direction at the same time. These punch marks 20 have a function as a tip edge tip guide at the time of drilling and cutting with a drill or the like for correcting the balance described above, and the number and size of the punch marks are the residual unbalance and the allowable unbalance mass, and the drill diameter used. A suitable distance is selected from the above, but it is desirable that the distance is an equal pitch distance from the viewpoint of balance. Further, the punch mark 20 may have any shape, for example, a conical punch mark 20A as shown in FIG. 7A, a cylindrical punch mark 20B as shown in FIG. Like the cylindrical punch mark 20C with a conical tip as shown in (c), any one can be selected according to the shape of the tip of the drill tip, and as shown in (d) of the figure, It may be a punch mark 20D with a rise 21. In any case, these punch marks 20 can be engraved on the upper surface of the upper balance ring 11 and the lower surface of the lower balance ring 15 at the same time from the thrust direction to the entire one surface at the time of making these parts, which is easy to form. is there. In FIG. 5, 22
Is a screw hole provided in the upper balance ring 11.

The upper balance ring 11 is then assembled based on the result of the balance measurement and the case study data in the assembled state as the polygon driving rotary body 8.
And / or the punch mark 20 part of the required position of the lower balance ring 15 is perforated by a drill.
Cutting for balance correction is performed to a depth determined by case-study data. At this time, if only the reference point is set, it is possible to easily and surely know which punch mark 20 is to be punched from now on, and the tip of the drill is guided to the punch mark 20 so that the drill position shifts. Without it, quick and reliable correction cutting can be performed. Further, in order to prevent the chips from adhering to the mirror surface of the polygon mirror 10 due to the perforation cutting, the saxion cutting method using a chip sacs (chip suction) jig is adopted to eliminate the adverse effects of the chips. Done The cutting hole formed by the modified perforation thus formed is shown as the cutting hole 23 of the upper balance ring 11 in FIG. 2, for example.

Then, when the correction punch cutting is completed, the polygon driven rotary body 8 is checked for balance by high-speed rotation using an air bearing in the same vertical arrangement as in the mounted state, and the conventional adhesiveness correction weight is used. Moreover, since it is not necessary to wait until it hardens and the balance can be checked immediately, the working time is short and the workability is good.

〔effect〕

As described above, according to the present invention, the processing cost can be reduced, the workability for the balance correction is good, the balance correction can be performed with high accuracy, and the balance correction structure can significantly reduce the cost. A polygon mirror driving device can be provided, and its practical value is great.

[Brief description of drawings]

1 to 7 relate to an embodiment of the present invention. FIG. 1 is a sectional front view of a polygon mirror driving device, FIG. 2 is a perspective view looking down at a polygon driving rotating body, and FIG. 3 is a polygon driving rotating. FIG. 4 is a front view of the polygon-driven rotating body, FIG. 5 is a plan view of the upper balance ring, FIG. 6 is a bottom view of the lower balance ring, and FIGS. d) is an explanatory view showing each embodiment of the punch mark, FIG. 8 is a sectional front view of a polygon mirror driving device showing a conventional example, and FIG. 9 is a sectional front view of a polygon mirror driving device showing another conventional example, First
FIG. 10 is an enlarged view of a main part of FIG. 1 ... Case body, 2 ... Bottom plate portion, 3 ... Cylindrical body portion, 4 ...
Upper plate part, 5 ... Shaft, 6 ... Groove for dynamic pressure generation, 7 ... Permanent magnet, 8 ... Polygon drive rotor, 9 ... Sleeve,
9a …… Mirror seat, 10 …… Polygon mirror, 11 …… Upper balance ring, 12 …… Permanent magnet, 13 …… Cap,
14 ... Magnet for motor, 15 ... Lower balance ring, 16 ... Screw, 17 ... Permanent magnet, 18 ... Mounting body, 19
...... Drive coil, 20,20A, 20B, 20C, 20D …… Punch mark, 21 …… Raised, 22 …… Screw hole, 23 …… Cutting hole.

Claims (1)

[Scope of utility model registration request] 1. A plurality of punch marks for guiding a balance correction punching process, which are located on the same circumference, are formed in a thrust direction on a part of a polygon driving rotary body to which a polygon mirror is integrally fixed. And a polygon mirror drive device.