JPH09189876A - Rotary polygon mirror driving motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce vibration and a noise when an optical informa tion processor prints and scans at high speed by making a bearing supporting rotation of a rotor a hemispherical fluid bearing. SOLUTION: This motor is provided with a stator 12, the rotator 41 and the bearing 50 arranged between the rotor 41 and the stator 12 and supporting the rotation of the rotor 41. This bearings 50 is made the hemispherical fluid bearing. Then, the hemispherical fluid bearing 50 is provided with hemispherical upper part inner ring 51 and lower part inner ring 52 holding a shaft 30 fixed to the rotor 41 therebetween so as to face each other and an outer ring 54 housed in the stator 12 and supporting the rotation of the upper part inner ring 51 and the lower part inner ring 52. In such a manner, a rotary polygon mirror driving motor reduces the vibration and the noise effectively when a laser printer or a laser scanner prints or scans at high speed using the hemispherical fluid bearing 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary polygon mirror drive motor, and more particularly to a rotary polygon mirror drive motor for driving a rotary polygon mirror in a laser printer and a laser scanner to change the optical path of a laser.

[0002]

2. Description of the Related Art Optical information processing devices such as laser printers and laser scanners have been developed in order to process a large amount of information at high speed using light. As shown in FIG. 1, such an optical information processing apparatus that prints or scans a large amount of information at high speed has a laser 1 having an excellent condensing property, a high-speed beam deflector 2, and a rotary polygon mirror 3. And a rotary polygon mirror drive motor 4.

FIG. 2 is a schematic sectional view of a bearing in a conventional rotary polygon mirror drive motor. As shown in FIG. 2, two ball bearings 40 are installed at an upper portion and a lower portion between the shaft 30 fixed to the rotor 41 of the motor and the bearing housing 10. FIG.
Reference numeral 11 indicates a bearing cover. The driving motor provided with the ball bearing 40 does not seriously affect printing and scanning in a printer or scanner driven at a low speed. However, a printer or scanner driven at a high speed seriously affects printing and scanning. That is, the rotating polygon mirror 3
This is because when the ball bearing 40, which is a contact type bearing, is used when printing and scanning are performed at a high speed of 20,000 RPM or more, vibration and noise are generated.

[0004]

SUMMARY OF THE INVENTION The present invention has been devised to solve the above-mentioned conventional problems, and an optical information processing apparatus such as a laser printer or a laser scanner can perform printing and scanning at high speed. It is an object of the present invention to provide a rotary polygon mirror drive motor having an improved bearing structure so that it can effectively reduce vibration and noise when performing.

[0005]

In order to achieve the above object, a rotary polygon mirror driving motor according to the present invention is installed between a stator and a rotor, and between the rotor and the stator. In a rotary polygon mirror drive motor including a bearing for supporting the bearing, the bearing is a hemispherical fluid bearing.

The hemispherical fluid bearing is a hemispherical upper inner ring and a lower inner ring sandwiched by shafts fixed to the rotor so as to face each other, and the upper inner ring and the lower inner ring housed in the stator. It is characterized by comprising an outer ring that supports rotation of the. A first coating film made of titanium or ceramic is formed on at least one lubricated surface of the inner ring and the outer ring.

The outer ring is made of a ceramic material. The second coating film made of DLC is further formed on the first coating film. As such, the rotary polygon mirror driving motor according to the present invention may use hemispherical fluid bearings to effectively reduce vibration and noise when a laser printer or a laser scanner performs printing and scanning at high speed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 3, a rotary polygon mirror driving motor according to the present invention rotates a rotary polygon mirror 3 as shown in FIG. 1 like a conventional rotary polygon mirror driving motor. A rotor 41 to be driven, a stator 12 installed around the rotor 41 and electrically interacting with the rotor 41 so that the rotor 41 rotates, a motor shaft 30 inserted in the rotor 41, A bearing 50 installed on the motor shaft 30 to rotatably support the motor shaft 30, and a bearing 50.
A bearing housing 10 containing here,
The above-mentioned bearing is a feature of the present invention in that it is a hemispherical fluid bearing unlike the conventional ball bearing.

The outer surface of the hemispherical fluid bearing 50 is hemispherical, and the upper inner ring 51 and the lower inner ring 52 are fixed to the shaft 30 so as to face each other, and the inner rings 51 and 52 fixed to the bearing housing 10 are rotated. An outer ring 54 that supports the inner ring 51, a spacer 53 that is inserted between the upper inner ring 51 and the lower inner ring 52 to maintain the clearance between the upper inner ring 51 and the lower inner ring 52, and the upper inner ring 51.
And a ring 55 for crimping the lower inner ring 52 to the motor shaft 30. Here, the ring 55 can be loosely fitted or screwed with the motor shaft 30.
In FIG. 3, reference numeral 12 designates a housing jaw for preventing the bearing 50 from being pushed in the axial direction.

Referring to FIG. 4, high carbon steel or WCo
5μs on the upper and lower inner rings 51 and 52
A titanium film 21 having a thickness of m to 10 μm is coated. Similarly, a titanium film 21 ′ having a thickness of 5 μm to 20 μm is coated on the lubrication surface of the outer ring 54 containing high carbon steel or WCo as a main component. Instead of the titanium coating films 21 and 21 ', ceramics, that is, a coating film made of Al ₂ O ₃ may be formed on the lubricating surfaces of the upper and lower inner rings 51, 52 and the outer ring 54. Then, the upper and lower inner rings 51, 52 and the outer ring 5
4 can be made of a ceramic material.

The above-mentioned coating film is used when the motor is started or stopped, that is, below the critical speed, and the upper and lower inner rings 5 are
The solid friction between the outer races 54 and the outer races 54 serves to reduce the wear of the upper inner races 51, 52 and the outer race 54. On the other hand, the upper and lower inner rings 51 and 52 and the outer ring 5
In order to further reduce the wear due to solid friction between the upper and lower inner rings 51 and 52, a thickness of 5 μm to 10 μ is formed on the titanium coating film 21 coated on the lower inner rings 51 and 52.
m's DLC (Dimond Like Carbon)
The membrane 22 is coated. The DLC coating film 22 has a linear expansion coefficient similar to that of the titanium coating film 21 and does not cause a peeling problem or a clearance change problem.
Since it is more wear resistant, the effect of solid friction can be reduced more effectively.

A groove 23 is formed in the DLC coating film 22. The groove 23 can be extended to the titanium coating film 21 through the DLC coating film 22 depending on the thickness of the DLC coating film 22 if necessary. This groove 23
Has a function of generating oil or air pressure when the upper and lower inner rings 51, 52 are rotated, and lifting the lower inner rings 51, 52 from the outer ring 54.

Further, the DLC coating film 22 and the groove 23 are provided on the outer ring 54. Hereinafter, one embodiment of a method of manufacturing a hemispherical fluid bearing installed in a rotary polygon mirror driving motor according to the present invention will be described in detail. Upper inner ring made of high carbon steel or WCo as the main component 5
1, 52 are lapped so that the sphericity is 0.15 μm to 0.25 μm, and a titanium film having a thickness of 5 μm to 20 μm is coated on the peripheral surface thereof. Then, a DLC having a thickness of 5 μm to 10 μm is formed on the titanium coating film.
Coat the membrane.

When coating the titanium film, a method of scanning a titanium ion beam or a method of depositing a titanium gas can be used. A ceramic film can be coated instead of the titanium film using such a method. In the same manner, the lubricating surface of the outer ring 54 is coated with a titanium or ceramic film having a thickness of 5 μm to 20 μm.

Next, a groove 23 is formed in the DLC coating film 22.
Is formed. The groove 23 can be formed by a method of chemically corroding a portion where the groove is formed or an electric discharge machining method. The process of assembling such a hemispherical fluid bearing into a drive motor is as follows. First, the upper inner ring 51 is fixed to the motor shaft 30, that is, the motor inner shaft 30 is prevented from slipping due to shrink fit. Next, after inserting the spacer 53 into the shaft 30, the outer ring 54
In short, the bearing housing 1 by shrink fitting
Insert within 0. The lower inner ring 52 is connected to the motor shaft 3
0 is inserted in the same manner and fixed to the motor shaft 30. Then, the ring 55 is forcibly fitted or screwed onto the motor shaft 30.

[0016]

As described above, the rotary polygon mirror driving motor according to the present invention can effectively reduce vibration and noise when the laser printer and the laser scanner perform printing and scanning at high speed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a general laser printer.

FIG. 2 is a sectional view showing a bearing portion of a conventional rotary polygon mirror drive motor.

FIG. 3 is a sectional view showing a bearing portion of a rotary polygon mirror drive motor according to the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

[Explanation of symbols]

 10 Bearing housing 21,21 'Titanium coating film 22 DLC coating film 23 Groove 30 Motor shaft 41 Rotor 50 Bearing 51 Upper inner ring 52 Lower inner ring 53 Spacer 54 Outer ring 55 Ring

Claims (10)

[Claims] 1. A rotary polygon mirror drive motor comprising a stator and a rotor, and a bearing installed between the rotor and the stator to support rotation of the rotor, wherein the bearing is a hemispherical fluid bearing. A rotary polygon mirror drive motor characterized in that 2. The hemispherical fluid bearing is a hemispherical upper inner ring and a lower inner ring sandwiched by a shaft fixed to the rotor so as to face each other, and the upper inner ring and the lower inner ring housed in the stator. The rotary polygon mirror drive motor according to claim 1, further comprising an outer ring that supports rotation of the rotary polygon mirror. 3. The rotary polygon mirror driving motor according to claim 2, wherein a first coating film made of titanium or ceramic is formed on at least one lubrication surface of the inner ring and the outer ring. . 4. The rotary polygon mirror drive motor according to claim 3, wherein the outer ring is made of a ceramic material. 5. The rotary polygon mirror driving motor of claim 3, further comprising a second coating film formed of DLC on the first coating film. 6. The rotary polygon mirror drive motor of claim 5, wherein a predetermined groove is formed in the second coating film. 7. The rotary polygon mirror driving motor of claim 6, wherein the groove extends to the first coating film. 8. The thickness of the first coating film is 5 μm.
The rotating polygon mirror drive motor according to claim 5, wherein the rotating polygon mirror drive motor has a thickness of about 20 m. 9. The thickness of the second coating film is 5 μm.
The rotating polygon mirror driving motor according to claim 5, wherein the driving motor has a thickness of 10 to 10 μm. 10. The thickness of the second coating film is 5 μm.
7. The rotating polygon mirror drive motor according to claim 6, wherein the rotating polygon mirror drive motor has a thickness of m to 10 μm.