JPH09131032A - Rotary-polygon-mirror driving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the deterioration of rotation accuracy and the life of a bearing caused by heating and to realize the excellent rotation accuracy and long life and the thin configuration at the low cost in a rotary-polygon-mirror driving apparatus used in an LBP. SOLUTION: A rotor 11, wherein a rotary shaft 1 and a rotor magnet 4 are provided and a rotary polygon mirror 10 is fixed, is provided. A stator 13 comprises a stator coil 9, which faces the rotor magnet 4 and generates electromagnetic torque, and a stator core 8, on which a magnetic body is laminated. A stator assembly 12 is constituted of the stator 13 and an iron-based stator substrate 6, on which a driving IC is mounted. These parts are provided. In this constitution, a bearing 7 for axially supporting the rotary shaft 1 is in contact with the above described stator substrate 6 and directly fixed to the stator core 8. Thus, the heat generated in the bearing by the air cooling effect of the rotary polygon mirror and the heat generated in the driving IC can be dissipated with the stator core and the stator substrate, and the reliability is improved.

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 driving device used for laser scanning in a laser beam printer (hereinafter abbreviated as LBP).

[0002]

2. Description of the Related Art In recent years, with the spread of LBP, a rotary polygon mirror driving device is required to be smaller and thinner and to have a lower cost. Under such circumstances, instead of the conventional bracket such as aluminum die casting, for example, the bearing is fixed to a resin-molded bracket or the like to achieve a thinner and lower cost. However, it is necessary to maintain high-precision performance with respect to rotation fluctuation (hereinafter referred to as jitter), noise, or surface tilt of the rotating polygon mirror. In addition, in order to achieve high precision, measures such as applying a fluid bearing to the bearing have been taken, and at the same time, the service life has been extended.

A conventional rotary polygon mirror driving device will be described below with reference to FIG. In FIG. 2, reference numeral 1 denotes a rotary shaft, which includes a rotary polygon mirror 10, a rotor magnet 4, and a rotor frame 3.
The rotor boss 2 to which the and are fixed are fixed by a method such as shrink fitting to form the rotor 11. A bracket 5 having a mounting portion for a rotary polygon mirror driving device has a stator coil 8 that is opposed to the rotor magnet 4 and that generates an electromagnetic torque, wound around a stator core 8 in which a rotor magnet 4 and a magnetic material forming a magnetic path are laminated. Stator 13 and drive I
A stator assembly 12 including a stator substrate 6 on which C15 is mounted, and a ball bearing 7 that supports the rotating shaft 1 are fixed.

The operation of the rotary polygon mirror driving device configured as described above will be described. First, when a current is supplied to the stator coil 9, an electromagnetic force is generated between the stator coil 9 and the rotor magnet 4, and the rotor 11 rotates about the rotating shaft 1 that is rotatably supported by the ball bearing 7 and is fixed to the rotor 11. Polarization scanning of the laser emitted by the rotating polygon mirror 10 is performed.

[0005]

However, in the above-mentioned conventional configuration, (1) since the stator substrate 6 is present between the rotor 5 and the bracket 5 fixing the bearing, the wind cooling effect by the rotation of the rotor 11 is obtained. Is insufficient for the bracket, so there is almost no cooling effect on the bearing, and improvement of bearing life is not required. (2) When the stator substrate 6 is made of a resin fiber such as paper phenol having a poor thermal conductivity, the effect of radiating the heat generated by the driving IC is insufficient and the margin for the allowable loss of the driving IC 15 is reduced. . (3) In order to obtain the cooling effect of the bearing and the drive IC 15, the stator substrate 6 is made of an iron substrate or the like having good thermal conductivity,
In addition, if the bracket 5 is made of aluminum die cast or the like having good thermal conductivity, the material cost becomes high. There was a problem that.

The present invention solves the above-mentioned conventional problems, and provides a rotary polygon mirror driving device which realizes a long life of a bearing, does not deteriorate the performance of a driving IC, and is low in cost and thin. The purpose is to do.

[0007]

To achieve this object, the present invention comprises a rotor to which a rotary shaft, a rotor magnet, and a rotary polygon mirror are fixed, and an electromagnetic torque is generated facing the rotor magnet. Stator coil, stator composed of stator core in which magnetic material is laminated, and drive IC
In a rotary polygon mirror drive device having a stator assembly composed of an iron-based stator substrate on which is mounted a bearing for supporting a rotating shaft is brought into contact with the iron substrate and directly fixed to a stator core. .

According to the present invention, it is possible to provide a rotary polygon mirror driving device which has a long life of a bearing due to an excellent heat dissipation effect and which does not deteriorate the performance of a driving IC and which can be made thin at low cost. You can

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a rotor having a rotary shaft, a rotor magnet, and a rotary polygon mirror fixed thereto, and a stator that faces the rotor magnet and generates an electromagnetic torque. A stator assembly including a stator including a coil, a stator core in which magnetic materials are laminated, and an iron-based stator substrate, and a bearing that supports a rotating shaft is in contact with the iron-based stator substrate, and the stator core It is a rotary polygon mirror driving device that is directly fixed to
With this structure, the heat generated by the bearing during the operation of the rotary polygon mirror driving device is directly conducted to the stator core and the iron-based stator substrate to radiate the heat, and the stator assembly is cooled by the wind cooling effect of the rotor rotation.

The invention according to claim 2 is a hydrodynamic bearing in which the bearing has a herringbone groove for generating a dynamic pressure on either the rotating shaft or the sleeve. It is a device, and by adopting a fluid bearing, while improving the accuracy of jitter and noise, or the tilting accuracy of the rotary polygon mirror, together with the excellent heat dissipation effect of claim 1,
It also has the effect of improving the life.

A third aspect of the present invention is the rotary polygon mirror driving device according to the first aspect, wherein the bearing is an oil-impregnated metal. With this configuration, an inexpensive oil-impregnated metal is used for the bearing,
Combined with the excellent heat dissipation effect of claim 1, it has the effect of extending the life of the bearing and reducing the cost.

According to a fourth aspect of the present invention, the bearing is in contact with the iron-based stator substrate and is fixed directly to the stator core by caulking or press-fitting, so that the rotary multi-face according to any one of the first to third aspects. Since it is a mirror drive device and the bearing is directly pressed against the stator core having excellent heat conduction, the heat dissipation effect can be improved as compared with other fixing methods (for example, adhesion), and a special fixing member is unnecessary.

According to a fifth aspect of the present invention, the iron-based stator substrate has a drive IC for driving the rotary polygon mirror drive device.
The rotary polygon mirror driving device according to any one of claims 1 to 4, wherein not only the heat generated by the bearing during operation of the rotary polygon mirror driving device but also the driving IC The generated heat is also radiated by the stator core and the iron-based stator substrate, and the stator assembly is cooled by the air-cooling effect of the rotor rotation.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a sectional view of a rotary polygon mirror driving apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is a rotary shaft, and a rotary polygon mirror 10, a rotor magnet 4, and a rotor frame 3 are provided. The rotor boss 2 to which is fixed is fixed by a method such as shrink fitting to form the rotor 11. The stator substrate 6 having a mounting portion for the rotary polygon mirror driving device is an iron substrate or the like having a high thermal conductivity, and a stator core 8 formed by laminating magnetic bodies forming a magnetic path of the rotor magnet 4 is opposed to the rotor magnet 4 and is electromagnetically coupled. A stator 13 around which a stator coil 9 that generates torque is wound, and a drive IC 15 that operates a rotary polygon mirror drive device are mounted to form a stator assembly 12. A herringbone groove is formed in the inner diameter of the bearing 7, which constitutes a fluid bearing and rotatably supports the rotary shaft 1. At this time, the bearing 7 is in contact with the stator substrate 6 and is directly caulked to the stator core 8.

The operation of the rotary polygon mirror driving device configured as described above will be described. First, when a current is supplied to the stator coil 9, an electromagnetic force is generated between the stator coil 9 and the rotor magnet 4, and the rotating shaft 1 that is rotatably supported by the bearing 7.
Rotation of the rotor 11 around the center of the laser causes the rotating polygon mirror 10 fixed to the rotor 11 to perform polarization scanning of the laser emitted. At this time, the wind generated by the rotary polygon mirror 10 hits the upper surface of the stator substrate 6.

As described above, according to the embodiment of the present invention, the driving IC 1 generated by the operation of the rotary polygon mirror driving device.
Since the drive IC 15 is directly mounted on the stator substrate 6, the heat of 5 can be radiated to the stator substrate 6 having good thermal conductivity, and the heat of the bearing 7 generated by the rotation of the rotor 11 can also be radiated to the stator substrate 6. Since they are in contact with each other and are directly caulked to the stator core 8, heat can be radiated to the stator core 8 and the stator substrate 6 having good thermal conductivity, and the stator substrate 6 is cooled by the air-cooling effect by the rotation of the rotor. 7 and the drive IC 15 can be cooled, the life of the bearing can be extended, and the performance of the drive IC 15 can be prevented from being deteriorated.

Although the bearing 7 is a fluid bearing in the embodiment, the same effect can be obtained even when the bearing 7 is an oil-impregnated metal, and the bearing 7 is directly crimped to the stator core 8 but the same effect can be obtained by direct press fitting. Is obtained.

[0018]

As described above, according to the present invention, a rotor having a rotating shaft and a rotor magnet, to which a rotating polygon mirror is fixed, a stator coil facing the rotor magnet and generating an electromagnetic torque, and a magnetic material are laminated. And a stator assembly composed of an iron-based stator substrate on which a drive IC is mounted, and a bearing that supports a rotating shaft is in contact with the iron substrate and is directly fixed to the stator core. By carrying out (1), the heat generated by the bearing due to the air-cooling effect of the rotary polygon mirror during operation of the rotary polygon mirror driving device can be dissipated by the stator core and the stator substrate, and the bearing performance can be improved. It was At the same time, the heat generated by the drive IC can also be radiated, and the deterioration of the performance of the drive IC can be prevented. (2) The cost can be reduced by reducing the number of constituent members. It is possible to realize an excellent rotary polygon mirror driving device.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotary polygon mirror driving device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional rotary polygon mirror driving device.

[Explanation of symbols]

 1 Rotating Shaft 2 Rotor Boss 3 Rotor Frame 4 Rotor Magnet 5 Bracket 6 Stator Board 7 Bearing 8 Stator Core 9 Stator Coil 10 Rotating Polyhedral Mirror 11 Rotor 12 Stator Assembly 13 Stator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinobu Taniguchi 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A stator comprising a rotating shaft, a rotor magnet, and a rotor to which a rotary polygon mirror is fixed, the stator coil facing the rotor magnet and generating an electromagnetic torque, and a stator core in which a magnetic material is laminated. A stator assembly including an iron-based stator substrate, and a bearing for rotatably supporting a rotating shaft is in contact with the iron-based stator substrate,
A rotary polygon mirror driving device that is directly fixed to the stator core. 2. A rotary polygon mirror driving apparatus according to claim 1, wherein the bearing is a hydrodynamic bearing having a herringbone groove for generating a dynamic pressure on either the rotating shaft or the sleeve. 3. The rotary polygon mirror driving device according to claim 1, wherein the bearing is an oil-impregnated metal. 4. The rotary polygon mirror driving device according to claim 1, wherein the bearing is in contact with the iron-based stator substrate and is directly fixed to the stator core by caulking or press fitting. 5. A driving IC for driving a rotary polygon mirror driving device is mounted on the iron-based stator substrate.
5. The rotary polygon mirror driving device according to claim 4.