JPH0876046A - Deflection type scanner - Google Patents

Abstract

PURPOSE: To reduce the quantity of the dynamic unbalance of a rotating body when it is rotated. CONSTITUTION: A rotor 14 is provided so that it can be rotated around, a shaft 13 as the center and a rotary polygon mirror 18 is fixed to the upper part of the rotor 14 by a pressing spring 19. Then, the rotating body is constituted of all of them. By arranging balance weights W1-W3 at three places of the upper surface 14a and the lower surface 14b of the rotor 14 and the upper surface 18a of the mirror 18, the quantity of the dynamic unbalance is corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection scanning device having a rotary polygonal surface for scanning a laser beam on a photosensitive member.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional deflection scanning device. A drive motor 3 having a rotatable rotor 2 is fixed inside a main body 1 of an optical box by screws or the like. Above the rotary polygon mirror 4, a holding spring 5, a holding plate 6,
It is fixed by a tension washer 7. Also, the rotor 2
A cutting portion 2b for correcting a dynamic unbalance amount is formed on the upper surface 2a of the. Further, the optical box body 1 is provided with a lid portion 8 that covers the inside thereof.

The rotor 2 is rotated by the drive motor 3, and the rotary polygon mirror 4 is also rotated accordingly, so that a laser beam emitted from a laser unit (not shown) is scanned on the photosensitive member.

[0004]

However, in the above-mentioned conventional example, the dynamic unbalance amount of the rotary polygonal mirror 4 is set to the drive motor 3.
Since the correction is made only by the rotor 2 of the above, the rotation speed of the rotary polygon mirror 4 becomes faster, and the unbalance amount due to the mounting error when the rotary polygon mirror 4 is mounted or the unbalance due to the axial thickness of the entire rotating body is caused. There is a problem that the influence of the amount becomes large, the vibration and noise of the drive motor 2 become large, and the performance of the deflection scanning device is adversely affected.

The object of the present invention is to solve the above problems,
An object of the present invention is to provide a deflection scanning device in which the amount of unbalance when the rotating body rotates is reduced.

[0006]

A deflection scanning apparatus according to the present invention for achieving the above object comprises a rotary mirror for deflecting and scanning a light beam emitted from a light beam generating means, and a rotary mirror for rotationally driving the rotary mirror. A deflection scanning device including a drive motor is characterized in that dynamic imbalance is corrected at three points of a rotating body including the rotating mirror.

[0007]

The deflection scanning apparatus having the above-mentioned structure corrects the dynamic imbalance at three points on the rotating body.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a configuration diagram of the first embodiment, in which a shaft 13 is rotatably fitted to a bearing portion 12 fixed to an optical box body 11. This shaft 1
A rotor 14 made of a permanent magnet is fixed to the rotor 3, and balance weights W1 and W2 are added to the upper surface 14a and the lower surface 14b of the rotor 14, respectively. Rotor 14
A stator 16 having a coil 15 built-in is fixed to the optical box body 11 on the outer side of the
An inner motor type drive motor 17 that rotates is configured. A rotary polygon mirror 18 is fixed to the upper part of the rotor 14 by a pressing spring 19.
A balance weight W3 is added to the upper surface 18a of the No. 8. Further, the inside of the optical box body 11 is covered with a lid 20.

When assembling the drive motor 17, first, the shaft 13 is fitted into the bearing portion 12, and the rotor 14 is attached to the shaft 13. Next, the rotor 14 is rotated around the shaft 13 to measure the dynamic unbalance amount, and balance weights W1 and W2 are added to the upper surface 14a and the lower surface 14b of the rotor 14 so as to remove the dynamic unbalance amount. To do. Furthermore, after the rotor 14 is incorporated in the stator 16 and the rotary polygon mirror 18 is attached to the upper part of the rotor 14 by the pressing spring 19, the dynamic unbalance amount of the rotor including the rotor 14, the rotary polygon mirror 18, and the pressing spring 19 is set. Is measured, and a balance weight W3 is added to the upper surface 18a of the rotary polygon mirror 18 so as to remove this dynamic unbalance amount.

In this way, the rotor 14 becomes the stator 1.
6. Even in the inner motor type drive motor 17 covered with the rotary polygon mirror 18, the mounting error when the rotary polygon mirror 18 is mounted and the dynamic unbalance amount of the rotor due to the thickness of the rotor 14 can be corrected. it can. Therefore, even when the drive motor 17 is rotationally driven at a high speed, it is possible to reduce the vibration due to the dynamic unbalance amount of the rotating body and reduce the noise accompanying the rotation.

If an ultraviolet curing adhesive is used as the balance weights W1 to W3, the balance weights W1 to W3
Since it can be cured immediately after the addition of, the assembling time can be shortened and the cost can be reduced. Also, if powder of glass beads, ceramics, metal, etc. is mixed in this adhesive, the specific gravity of the balance weights W1 to W3 can be increased, so a large amount of dynamic imbalance can be removed with a small amount of adhesive. be able to. Furthermore, the upper surface 1 of the rotary polygon mirror 18
If 8a is located at the center of the rotating body, the amount of dynamic imbalance due to the axial thickness of the rotating body can be eliminated.

FIG. 2 is a block diagram of the second embodiment.
The same reference numerals as in FIG. The upper surface 14a and the lower surface 14b of the rotor 14 and the upper surface 18 of the rotary polygon mirror 18
Circular grooves 14c, 14d and 18b are formed in a, respectively.

By assembling the apparatus as in the first embodiment and adding the balance weights W1 to W3 to the grooves 14c, 14d and 18b respectively, the balance weights W1 to W3 are added at a fixed distance from the respective rotation centers. Therefore, the workability is improved and the grooves 14c, 14d, 1
By adding the balance weights W1 to W3 so as to fill the 8b, it is possible to widen the adhesive area of the adhesive used as the balance weights W1 to W3, thus preventing the peeling of the balance weights W1 to W3 during high speed rotation. can do.

In this embodiment, the grooves 14c, 14d, 1
Although 8b is provided at three positions, that is, the upper surface 14a of the rotor 14, the lower surface 14b, and the upper surface 18a of the rotary polygon mirror 18, the grooves may be formed at only one or two of them.

FIG. 3 is a block diagram of the third embodiment and shows a perspective view of the rotor 14. In this third embodiment,
The first embodiment is performed by correcting the dynamic unbalance amount of the rotating body by cutting off a part of the upper surface 14a and the lower surface 14b of the rotor 14 as the cutting portion 14e without adding the balance weights W1 to W3. The same effect can be obtained.

The cutting portion 14e is the upper surface 1 of the rotor 14.
Either one or both of 4a and the lower surface 14b may be provided, or a cutting portion may be formed on the upper surface 18a of the rotary polygon mirror 18.

[0017]

As described above, the deflection scanning apparatus according to the present invention can effectively correct the dynamic imbalance, reduce the vibration of the drive motor, and reduce the performance due to the vibration of the deflection scanning apparatus. It is possible to suppress the noise, and it is possible to reduce noise caused by rotation of the noisy motor.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a configuration diagram of a second embodiment.

FIG. 3 is a perspective view of a third embodiment.

FIG. 4 is a sectional view of a conventional deflection scanning device.

[Explanation of symbols]

 11 Optical Box Main Body 12 Bearing 13 Shaft 14 Rotor 15 Coil 16 Stator 17 Drive Motor 18 Rotating Polygonal Mirror 19 Presser Spring 20 Lid W1-W3 Balance Weight

Claims (4)

[Claims] 1. A deflection scanning device comprising a rotating mirror for deflecting and scanning a light beam emitted from a light beam generating means, and a drive motor for rotationally driving the rotating mirror, wherein a rotating body including the rotating mirror is provided. A deflection scanning device characterized by correcting dynamic imbalance at a location. 2. The drive motor is an inner motor, and one surface or both surfaces of a rotor portion of the rotor motor for correcting the dynamic imbalance is covered with a rotary polygon mirror or a part of the drive motor. Deflection scanning device. 3. The method according to claim 2, wherein recesses are formed at one, two or three positions on the surface that corrects the dynamic imbalance in the rotor portion and the rotary boundary, and balance weights are mounted in these recesses. Deflection scanning device. 4. The dynamic imbalance is corrected by scraping off the correction surface at one, two or three correction surfaces for correcting the dynamic imbalance at the three locations. The deflection scanning device according to.