JP3674991B2 - Rotating polygon mirror drive - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a rotary polygon mirror driving device used for laser scanning in a laser beam printer (hereinafter abbreviated as LBP) or the like.
[0002]
[Prior art]
In recent years, the penetration of the high-speed LBP with high printing quality as an output device has increased. The printing accuracy of this LBP is greatly influenced by the mechanical accuracy of the optical scanner unit, but in particular, the rotating polygon mirror drive device uses the center of the rotating polygon mirror, the center of the rotating shaft, and the device mounting as the standard of the LBP optical system. Since it is necessary to configure the center of the positioning part with high accuracy, various methods are employed.
[0003]
A conventional rotary polygon mirror driving device will be described below.
FIG. 3 is a sectional view of a conventional rotary polygon mirror driving apparatus. In FIG. 3, reference numeral 1 denotes a rotating shaft, and a rotor boss 2 to which the rotary polygon mirror 10, the rotor magnet 4, and the rotor frame 3 are fixed is fixed by a method such as shrink fitting to constitute the rotor 11. The bracket 5 having the mounting portion of the rotary polygon mirror driving device and the mounting positioning portion 5a is a stator that generates electromagnetic torque opposite to the rotor magnet 4 on the stator core 8 in which the rotor magnet 4 and a magnetic material constituting a magnetic path are laminated. A stator 12 composed of a stator winding 13 with a coil 9 and a stator substrate 6 on which a drive IC 14 is mounted, and a bearing 7 that supports the rotary shaft 1 are fixed.
[0004]
The operation of the rotary polygon mirror driving apparatus configured as described above will be described. First, when an electric current is supplied to the stator coil 9, an electromagnetic force is generated between the rotor magnet 4 and the rotor 11 rotates around the rotating shaft 1 supported by the bearing 7 to be fixed to the rotor 11. Polarization scanning of the laser irradiated by the rotating polygonal mirror 10 is performed.
[0005]
[Problems to be solved by the invention]
However, in the conventional configuration described above, it is difficult to respond to customer requirements because it is necessary to create a bracket according to the dimensions, shape, and material of the device mounting positioning portion required by the customer. There was a problem in that it was not possible to share components, and improvement in product cost was not required.
[0006]
In addition, when the bearing is a ball bearing, errors due to the mounting accuracy between the bracket and the ball bearing and the clearance between the ball bearing and the rotating shaft are large, and it is difficult to reduce the center misalignment between the rotating shaft and the device mounting positioning portion. (The ability of φ0.02 to φ0.03 in terms of coaxiality).
[0007]
The present invention solves the above-mentioned conventional problems, and can be easily and inexpensively applied to a wide range of sizes, shapes and materials of positioning portions for mounting devices required by customers. It is an object of the present invention to provide a rotary polygon mirror drive device that realizes cost reduction by sharing the components of the drive device and that has a central axis of the rotary polygon mirror and a device mounting positioning portion configured with high accuracy.
[0008]
[Means for Solving the Problems]
In order to achieve this object, a rotary polygon mirror driving apparatus according to the present invention includes a rotor having a rotary shaft and a rotor magnet to which the rotary polygon mirror is fixed, and a stator winding that generates electromagnetic torque opposite to the rotor magnet. a bearing for supporting the rotary shaft has a stator formed by a metal base printed circuit board fixed, the bearing outer diameter cylindrical portion formed by co-processed and the bearing inner diameter is formed, out of the bearing The positioning member for attaching the rotary polygon mirror driving device is directly fixed to the diameter cylindrical portion . A hydrodynamic bearing was adopted as the bearing.
[0009]
[Action]
With this configuration, it is possible to easily and inexpensively handle a wide range of dimensions, shapes, and materials of the positioning part for mounting the device required by the customer, and it can be reduced by sharing the components of the rotary polygon mirror driving device. Cost reduction can be realized.
[0010]
In addition, the adoption of the hydrodynamic bearing makes it possible to realize a rotary polygon mirror driving device in which the coaxiality between the central axis of the rotary polygon mirror and the device mounting positioning portion is configured with high accuracy.
[0011]
【Example】
(Example 1)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[0012]
In FIG. 1, reference numeral 1 denotes a rotating shaft, and a rotor boss 2 to which a rotary polygon mirror 10, a rotor magnet 4 and a rotor frame 3 are fixed is fixed by a method such as shrink fitting to constitute a rotor 11. The stator substrate 6 having a mounting portion of the rotary polygon mirror driving device is a metal base printed circuit board such as an iron substrate. The stator core 8 is formed by laminating the rotor magnet 4 and a magnetic material constituting a magnetic path so as to oppose the rotor magnet 4 and electromagnetically. A stator winding 13 having a stator coil 9 that generates torque and a driving IC 14 for operating the rotary polygon mirror driving device are mounted to constitute the stator 12. The bearing 7 is directly fixed to the stator substrate 6, and a herringbone groove is formed on the inner diameter of the bearing 7 to constitute a fluid bearing and rotatably support the rotary shaft 1. The collar 15 is a positioning member for mounting the device and is directly caulked to the outer diameter cylindrical portion 7a of the bearing 7 or is press-fitted and fixed.
[0013]
The operation of the rotary polygon mirror driving apparatus configured as described above will be described. First, when an electric current is supplied to the stator coil 9, an electromagnetic force is generated between the rotor magnet 4 and the rotor 11 rotates around the rotating shaft 1 supported by the bearing 7 to be fixed to the rotor 11. Polarization scanning of the laser irradiated by the rotating polygonal mirror 10 is performed. At this time, the rotating shaft 1 floats and rotates at the mechanical center of the bearing 7 due to the pressure generated by the rotation. In addition, since the inner diameter and the outer diameter cylindrical portion 7a of the bearing 7 are finished by simultaneous processing, the coaxiality between the outer diameter cylindrical portion 7a and the rotary shaft 1 becomes substantially zero.
[0014]
As described above, according to the first embodiment, by directly fixing the collar 15 to the outer diameter cylindrical portion 7a of the bearing 7, the size, shape and material of the device mounting positioning portion 5a desired by the customer can be obtained. Therefore, it can be easily and inexpensively configured without changing the shape of the bearing 7. In addition, the bearing 7 can be shared, so that the cost for developing and manufacturing the bearing can be reduced, and the coaxial accuracy of the rotary shaft 1 and the collar 15 can be easily increased.
[0015]
In addition, the adoption of the hydrodynamic bearing makes it possible to realize a rotary polygon mirror driving device in which the coaxiality between the central axis of the rotary polygon mirror and the device mounting positioning portion is configured with high accuracy.
[0016]
In this embodiment, the hydrodynamic bearing is used as the bearing, but it goes without saying that the same applies to ordinary oil-impregnated metal.
[0017]
(Example 2)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
[0018]
In FIG. 2, reference numeral 1 denotes a rotating shaft and a rotor boss 2 to which the rotary polygon mirror 10, the rotor magnet 4 and the rotor frame 3 are fixed is fixed by a method such as shrink fitting to constitute the rotor 11. The stator substrate 6 having a mounting portion of the rotary polygon mirror driving device is a metal base printed circuit board such as an iron substrate. The stator core 8 is formed by laminating the rotor magnet 4 and a magnetic material constituting a magnetic path so as to oppose the rotor magnet 4 and electromagnetically. A stator winding 13 having a stator coil 9 that generates torque and a driving IC 14 for operating the rotary polygon mirror driving device are mounted to constitute the stator 12. The bearing 7 is directly fixed to the stator substrate 6, and the outer diameter portion shares the device mounting positioning portion 5 a and is coaxially processed with the inner diameter of the bearing 7. A herringbone groove is formed in the inner diameter of the bearing 7 to form a fluid bearing and rotatably support the rotary shaft 1.
[0019]
The operation of the rotary polygon mirror driving apparatus configured as described above will be described. First, when an electric current is supplied to the stator coil 9, an electromagnetic force is generated between the rotor magnet 4 and the rotor 11 rotates around the rotating shaft 1 supported by the bearing 7 to be fixed to the rotor 11. Polarization scanning of the laser irradiated by the rotating polygonal mirror 10 is performed. At this time, the rotating shaft 1 floats and rotates at the center of the bearing 7 due to the pressure generated by the rotation.
[0020]
As described above, according to the second embodiment, the device mounting positioning portion 5a is applied to the outer diameter portion of the bearing 7 so as to be coaxial with the inner diameter of the bearing 7, whereby the center of the bearing 7 and the device mounting positioning portion 5a are formed. The coaxiality can be made highly accurate, and the use of a hydrodynamic bearing makes it possible to reduce the coaxiality between the center of the bearing 7 and the center of the rotary shaft 1, and positioning the central axis of the rotary polygon mirror and the device mounting position. Therefore, it is possible to realize a rotary polygon mirror driving device having a high degree of concentricity with the unit and having a low cost without using a member such as a collar.
[0021]
【The invention's effect】
As described above, the present invention adopts a hydrodynamic bearing as the bearing 7 and applies the apparatus mounting positioning portion 5a to the outer diameter portion of the bearing 7 so as to be coaxial with the inner diameter of the bearing 7.
(1) It is possible to realize a rotary polygon mirror driving device in which the coaxiality between the central axis of the rotary polygon mirror and the device mounting positioning portion is configured with high accuracy. (Concentricity φ0.02 or less)
Further, by directly fixing the collar 15 to the bearing 7,
(2) It is easy and inexpensive to deal with a wide range of dimensions, shapes and materials of the positioning part for mounting the device desired by the customer.
(3) The components of the rotary polygon mirror driving device can be shared, and the cost can be reduced.
An excellent rotating polygon mirror driving device can be realized.
[Brief description of the drawings]
FIG. 1 is a sectional view of a rotary polygon mirror driving apparatus according to a first embodiment of the present invention. FIG. 2 is a sectional view of a rotary polygon mirror driving apparatus according to a second embodiment of the present invention. Sectional view of mirror drive device [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Rotor boss 3 Rotor frame 4 Rotor magnet 5 Bracket 5a Positioning part 6 Stator substrate 7 Bearing 7a Outer diameter cylindrical part 8 Stator core 9 Stator coil 10 Rotating polygon mirror 11 Rotor 12 Stator 13 Stator winding 14 Drive IC
15 colors

Claims (6)

A metal base on which a rotor having a rotating shaft and a rotor magnet and having a rotating polygon mirror fixed thereto, a stator having a stator winding facing the rotor magnet and generating electromagnetic torque, and a bearing supporting the rotating shaft are fixed Rotating with a printed circuit board, wherein the bearing has an outer diameter cylindrical portion formed by simultaneous processing with the bearing inner diameter, and a rotary polygon mirror drive positioning member fixed directly to the outer diameter cylindrical portion of the bearing Polyhedral mirror drive device.   2. The rotary polygon mirror driving device 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.   2. 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 device mounting member is fixed directly to the bearing by caulking.   4. The rotary polygon mirror driving device according to claim 1, wherein the device mounting positioning member is fixed directly to the bearing by press-fitting. 6. The rotary polygon mirror driving device according to claim 5, wherein the bearing is made of a copper-based material.

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