JP2002365580A - Rotating polygon mirror, and working equipment and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide working equipment of a rotating polygon mirror which holes the bearing surface of a dynamic pressure bearing over the entire length and the circumference at uniform holding power by means of the holding means of the hydraulic expansion type to work the mirror plane of the rotating polygon mirror, forms all mirror planes at an angle which is fixed with respect to the central axis of rotation of the rotating polygon mirror with high angle accuracy and works the surface with high planarity accuracy. SOLUTION: In the rotating polygon mirror, the dynamic pressure bearing surface is integrally formed on a metal member 105, and a plurality of mirror planes are formed at equal intervals in a circumferential direction. The dynamic pressure bearing surface consists of a through-hole, having almost the same diameter as or larger than that of the dynamic pressure bearing for inserting the dynamic pressure bearing. The dynamic pressure bearing surface functions also as a holding part, to be held by the holding means 103 in order to form the mirror plane on the metal member 105.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus such as a copying machine, a laser beam printer, a facsimile, etc.
The present invention relates to a rotary polygon mirror that can be used as an optical deflector for an image reading device and the like, and also relates to a rotary polygon mirror processing device and a rotary polygon mirror processing method.

[0002]

2. Description of the Related Art In an image writing apparatus or an image forming apparatus used for a laser copying machine, a laser beam printer, a laser facsimile, or the like, a laser beam is scanned on a photoconductor or a document in a main scanning direction, and the photoconductor or the document is subordinate. By moving the photoconductor in the scanning direction, a predetermined electrostatic latent image is formed on the photoconductor. An optical deflector is used to scan the laser beam in the main scanning direction, and a rotary polygon mirror is generally used as the optical deflector. The rotating polygon mirror has a plurality of light reflecting surfaces formed at equal intervals on the outer peripheral surface, and when the rotating polygon mirror is driven at a high speed by a motor to irradiate the laser beam onto the light reflecting surface, the laser beam is reflected on each light reflecting surface. , And scans the surface of the photoreceptor to form an electrostatic latent image or write an image on the photoreceptor as described above.

The processing and assembly accuracy including the surface roughness, flatness, surface tilt accuracy, etc. of each light reflecting surface of the rotating polygon mirror greatly affects the accuracy of the condensing spot of scanning light, the accuracy of scanning pitch, etc. The processing accuracy of each light reflecting surface of the polygon mirror must be strictly controlled. As an example of a conventional rotary polygon mirror processing device,
There is one described in JP-A-2000-233334.
An object of the invention described in this publication is to obtain a rotary polygon mirror processing apparatus and a processing method that can improve the accuracy of each component and the assembling accuracy at a low cost and respond to a request for a high-speed rotation at a low cost. I do.

In order to achieve the above object, the invention described in the above-mentioned publication holds a rotating operation body which is rotated and a rotation center member which is enlarged and reduced to be integral with a rotating polygon mirror, and releases the holding. An angle indexing mechanism, wherein the holding means comprises: an expansion / contraction section to perform the rotation operation of the rotary operating body to the expansion / contraction section to enlarge and reduce the expansion / contraction section. By rotating the holding means by a predetermined angle, the rotation angle is set to a predetermined rotation angle position while calculating the rotation angle, and each mirror surface of the rotary polygon mirror is machined. It is stated that the expanding / contracting section is preferably made of metal or non-metal having a lower hardness than the rotation center member held by the expanding / contracting section.

[0005]

According to the invention described in the above publication, the accuracy of each component and the accuracy of assembling can be improved at low cost, and the rotating polygon mirror can meet the demand for high-speed rotation at low cost. The intended purpose of obtaining a processing apparatus and a processing method can be achieved. However, when the rotating polygon mirror is held by the holding means, uniform contact cannot be obtained over the entire length of the bearing (rotation center member) between the enlarged / reduced portion of the holding means and the bearing surface. A uniform holding force cannot be obtained over the entire length. Specifically, since the upper end side of the expanding / contracting portion is largely opened, the holding force is concentrated on the upper end side, and is fixed in a so-called one-sided state.

[0006] Originally, the center axis of the bearing and the center axis of the holding means must be fixed and aligned, and each mirror surface must be formed at a fixed angle with respect to the center axis of the bearing. But,
In the above-mentioned conventional example, since each mirror surface is formed in a state where the respective center axes are not coincident with each other, the angle variation of each mirror surface with respect to the center axis of the bearing increases. Also, the holding force is biased in the axial direction (the upper holding force is strong and the lower side is weak)
Is generated, so that a minute vibration is caused at the time of processing, and the flatness of the mirror surface after the processing is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and the invention according to claim 1 uses a hydraulic expansion type holding means to extend the entire bearing surface of a dynamic pressure bearing. Holds with a uniform holding force over the entire circumference, enables the processing of the mirror surface of the rotating polygon mirror, and all mirror surfaces are formed at a fixed angle with respect to the rotation center axis of the rotating polygon mirror, resulting in high angular accuracy It is another object of the present invention to provide a rotary polygon mirror processing apparatus capable of processing with high accuracy in flatness.

According to a second aspect of the present invention, the mirror surface of the rotary polygon mirror is machined while being held by the hydraulic expansion type holding means with a uniform holding force over the entire length and the entire circumference of the bearing surface of the dynamic pressure bearing. Accordingly, an object of the present invention is to provide a processing method of a rotary polygon mirror in which all mirror surfaces are formed at a fixed angle with respect to the rotation center axis of the rotary polygon mirror, and the angle accuracy is high and the flatness accuracy can be processed with high accuracy. I do.

According to a third aspect of the present invention, the mirror surface of the rotary polygon mirror is machined while being held by the hydraulic expansion type holding means with a uniform holding force over the entire length and the entire circumference of the bearing surface of the dynamic pressure bearing. The object of the present invention is to provide a rotating polygonal mirror in which all mirror surfaces are formed at a fixed angle with respect to the rotation center axis of the rotating polygonal mirror, and the angle accuracy is high, and the flatness accuracy is also high. And

According to a fourth aspect of the present invention, the deformation stress when the dynamic pressure bearing surface is held by the hydraulic expansion type holding means is transmitted to the mirror surface, with the components constituting the mirror surface portion and the dynamic pressure bearing portion being separate components. It is an object of the present invention to provide a rotary polygon mirror that can reduce the number of times the mirror is mirror-finished and can increase the mirror surface accuracy after the mirror surface processing.

According to a fifth aspect of the present invention, the mirror surface portion and the dynamic pressure bearing portion are integrally formed of the same material, and the deformation stress when the dynamic pressure bearing surface is held by the hydraulic expansion type holding means is transmitted to the mirror surface. It is an object of the present invention to provide a rotary polygon mirror capable of reducing the number of mirrors and improving the mirror surface accuracy after mirror surface processing.

The invention according to claims 6, 7 and 8 reduces the transmission of the deformation stress to the mirror surface when the dynamic pressure bearing surface is held by the hydraulic expansion type holding means. It is an object of the present invention to provide a rotating polygon mirror capable of achieving a high mirror accuracy after processing.

An object of the present invention is to provide a rotary polygon mirror having a high damping effect on vertical vibration.

According to a tenth aspect of the present invention, there is provided a rotary polygonal mirror having an enhanced damping effect against vertical vibration as in the ninth aspect of the present invention, wherein the dynamic pressure bearing surface is held by the hydraulic expansion type holding means. It is an object of the present invention to provide a rotary polygon mirror capable of reducing transmission of deformation stress to a mirror surface and improving mirror surface accuracy after mirror surface processing.

[0015]

According to the first aspect of the present invention,
In a rotary polygon mirror processing apparatus for holding a metal member as a workpiece by a holding means and mirror-finishing the same, the holding means is a dynamic pressure bearing of a dynamic pressure bearing formed integrally with the metal member. It is a hydraulic expansion type holding means for holding a surface.

According to a second aspect of the present invention, there is provided a rotary polygon mirror processing method, wherein the hydraulic expansion type holding means provided in the rotary polygon mirror processing apparatus is formed integrally with a metal member as a workpiece. The dynamic pressure bearing surface of the selected dynamic pressure bearing is held, and the workpiece is mirror-finished in this state.

According to a third aspect of the present invention, there is provided a rotary polygon mirror in which a dynamic pressure bearing surface is integrally formed on a metal member and a plurality of mirror surfaces are formed at equal intervals in a circumferential direction. The pressure bearing surface has a through hole substantially the same as or larger than the diameter of the dynamic pressure bearing for inserting the dynamic pressure bearing, and holding means for forming a mirror surface on the metal member. Characterized in that it also serves as a holding portion held by the.

According to a fourth aspect of the present invention, in the third aspect, a sleeve is fixed inside the metal member, and a dynamic pressure bearing surface is formed in a through hole of the sleeve.

According to a fifth aspect of the present invention, in the third aspect, a surface treatment film is formed on the metal member, and a dynamic pressure bearing surface is formed on the surface treatment film.

According to a sixth aspect of the present invention, in accordance with the fifth aspect of the present invention, the deformation stress when the dynamic pressure bearing surface is held on the metal member by the holding means is prevented from being transmitted to the mirror surface. A stress relief portion is formed.

According to a seventh aspect of the present invention, in the sixth aspect, the stress removing portion is a circumferential groove formed between the dynamic pressure bearing surface and the mirror surface. According to an eighth aspect of the present invention, in the invention of the seventh aspect, the circumferential groove has an axial position overlapping the dynamic pressure bearing surface and the mirror surface in the axial direction.

According to a ninth aspect of the present invention, in the third aspect, one end of the through hole is closed by a closing member. According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the metal member is characterized in that one end of the through hole into which the closing member is fitted is a thin cylinder.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a rotary polygon mirror, a processing apparatus and a processing method thereof according to the present invention will be described with reference to the drawings.

Embodiment 1 First, an embodiment of a rotary polygon mirror processing apparatus will be described with reference to FIGS. In FIG.
Indicates an angle indexing mechanism. This angle indexing mechanism 10
A jig base 102 is mounted on 1. The jig base 102 is a mandrel 1 which is a hydraulic expansion type holding means.
In order to fit 03 from top to bottom, it has a cylindrical center hole oriented in the vertical direction, and has a circular jetty 102a in which the periphery of the upper surface of the center hole rises. The mandrel 103 has a flange 103a at a position near the lower end in a state where the mandrel 103 is oriented in the vertical direction. Mandrel 10 forming a cylindrical surface
3 is fitted into the center hole of the jig base 102, so that the lower surface of the flange 103a hits the jetty 102a of the jig base 102, the mandrel 103 is positioned in the vertical direction, and the center axis of the mandrel 103 is aligned. The jig base 102 is positioned so as to coincide with the central axis. The center axis of the jig base 102 is adjusted in advance so as to coincide with the center axis of rotation of the angle indexing mechanism 101.

The angle indexing mechanism 101 is connected to a mandrel 103 serving as the holding means via a jig base 102.
Can be rotated by a predetermined angle to determine the rotation angle. As will be described in detail later, the mandrel 103
This is holding means for holding the rotary polygon mirror 105 as a workpiece, and the rotary polygon mirror 105 is fitted and held in the workpiece holding portion. Rotating polygon mirror 10 to be processed
5 is made of a metal member, for example, aluminum. A rotating tool 104 is arranged on the side of the mandrel 103. The rotary tool 104 is driven to rotate about a horizontal rotation shaft 104a. A machining tool 106 is attached to the rotating tool 104 on the side facing the rotating polygon mirror 105, and the machining tool 106 is mounted around the rotation axis 104a.
The rotary polygon mirror 1 is moved by moving the rotary tool 104 in the horizontal and vertical directions while rotating the mirror in a vertical plane.
05 can be processed. When the processing of one light reflecting surface is completed, the angle indexing mechanism 10
A predetermined rotation angle is determined while rotating the mandrel 103 together with the jig base 102 and the rotary polygon mirror 105 by 1, and the jig base 102 is fixed at that position, and another light reflecting surface is similarly processed by the rotating tool 104. be able to.

FIG. 2 shows an example of a mandrel 103 which is a hydraulic expansion type holding means. In FIG. 2, the mandrel 1
Reference numeral 03 denotes the flange portion 103a, an extension portion 103b serving as a workpiece holding portion, a piston 103c for applying hydraulic pressure to the extension portion 103b, an operation screw 103d for moving the piston 103c, and an air bleeding portion 103b. Seal screw 1
03e. When the piston 103c is moved toward the extension 103b by turning the operation screw 103d, the hydraulic pressure inside the extension 103b increases, and the extension 1
03b expands and the outer diameter increases. The extended portion 103b has a length L in the axial direction, extends evenly over the entire length L, and applies pressure evenly over the entire length L, and the rotary polygon mirror which is a workpiece and is made of a metal member. 105 can be retained.

Next, a rotary polygon mirror processing method using the rotary polygon mirror processing apparatus described above will be described step by step. First, the center through hole of the rotary polygon mirror 105 is inserted into the extension 103b with the extension 103b of the mandrel 103 contracted. Actuating screw 10 for mandrel 103
By turning 3d, the piston 103c moves, and the hydraulic pressure rises. At the same time as the oil pressure rises due to the movement of the piston 103c, the oil pressure inside the expansion portion 103b also rises,
b expands. Due to the expansion of the expansion portion 103b, the outer diameter increases, and the gap between the rotating polygon mirror 105 inserted into the expansion portion 103b and the hydrodynamic bearing surface (peripheral surface of the central through-hole) decreases, thereby reducing the mandrel. The extended portion 103b of 103 and the dynamic pressure bearing surface are in close contact over the entire length of the dynamic pressure bearing, and the rotary polygon mirror 105 is fixed.

Next, the rotary tool 104 is driven to rotate, and one light reflecting surface of the rotary polygon mirror 105 is mirror-finished by the processing tool 106 attached to the rotary tool 104. When the mirror finishing of one light reflecting surface is completed, a predetermined rotation angle is determined while rotating the jig base 102, the mandrel 103 and the rotary polygon mirror 105 by the angle indexing mechanism 101, and the jig base 102 is fixed at that position. Rotating tool 1
In step 04, another light reflecting surface is similarly mirror-finished. The rotation center axis of the angle indexing mechanism 101 and the mandrel 10
Since the center axes of the dynamic pressure bearing 3 and the dynamic pressure bearing coincide with each other, the mirror-finished light reflecting surfaces are finished with a high precision in the relative positional relationship with the central axis of the dynamic pressure bearing. The light reflecting surfaces are sequentially processed in this way, and when all the light reflecting surfaces have been processed, the rotating polygon mirror 105 is removed from the mandrel 103.

According to the embodiment described above, by expanding the outer diameter of the extension portion 103b of the mandrel 103, the rotary polygon mirror 105 is held by a hydrodynamic bearing surface integral therewith, and the angle indexing mechanism 101 is used to hold the rotary polygon mirror 105. Mandrel 1
03 is rotated by a predetermined angle, and each light reflecting surface of the rotating polygon mirror 105 is mirror-finished while calculating the rotation angle. Therefore, the extended portion 103b of the mandrel 103 is uniformly enlarged, and the center axis of the rotating polygon mirror 105 is adjusted. Mandrel 10
3 coincides with the central axis. Therefore, the mandrel 1 is rotated together with the rotary polygon mirror 105 by the angle indexing mechanism 101.
By rotating the lens 03 and determining a predetermined rotation angle, the position accuracy and parallelism of each light reflecting surface of the rotary polygon mirror 105 with respect to the rotation center axis can be kept good, and mirror finishing can be performed with high accuracy.

The extended portion 103b of the mandrel 103 as a holding means is provided with a dynamic pressure bearing surface integral with the rotary polygon mirror 105.
Since the light reflection surface is mirror-finished while being held by the above, there is no accumulation of component accuracy errors, and a rotating polygon mirror with good surface tilt accuracy can be easily obtained at low cost. In addition, the accumulation of accuracy errors due to the assembly of parts is small, and from this point, a highly accurate rotating polygon mirror can be obtained. Since the mirror finishing can be performed with high accuracy in this manner, the speed and quality of the optical scanning device using the rotating polygon mirror can be improved.

If the holding force of the dynamic pressure bearing surface integral with the rotary polygon mirror 105 by the extension portion 103b of the mandrel 103 is weak, the rotary polygon mirror 105 moves during processing, and the surface accuracy of the processed light reflecting surface deteriorates. In some cases, rotating polygon mirror 1
05 moves, and an excessive load is applied to the dynamic pressure bearing portion, the mandrel 103, the rotary tool 104, and the like, which may cause damage. On the other hand, if the holding force of the rotating polygon mirror 105 by the mandrel expansion portion 103b is too strong, the dynamic pressure bearing portion and the rotating polygon mirror 105 are held in a deformed state. Then, the extended portion 103b of the mandrel 103 is reduced, and the rotating polygon mirror 10 is rotated.
When the member 5 is removed, the dynamic pressure bearing portion and the rotary polygon mirror 105 return to their original shapes, and the processing surface of the rotary polygon mirror 105 is deformed, thereby deteriorating the surface accuracy.

However, according to the above-described embodiment, since the entire dynamic pressure bearing surface of the rotary polygon mirror 105 is uniformly held by the extended portion 103b of the mandrel 103, deformation of the dynamic pressure bearing surface and the rotary polygon mirror 105 is prevented. The surface accuracy of the mirror surface, which is a processing surface, can be kept high. Also, mandrel 10
By controlling the amount of movement of the third operating screw 103d and the piston 103c, the holding force by hydraulic pressure can be managed, so that the above-mentioned problems due to excessive or insufficient holding force can be prevented.

Next, an embodiment of a rotary polygon mirror according to the present invention and a dynamic pressure air bearing type optical deflector having the rotary polygon mirror will be described with reference to FIGS. FIG. 3-
In FIG. 5, a reference surface 1a for attachment to an optical housing (not shown) is formed on the lower surface of the housing 1. At the center of the upper surface of the housing 1, a cylindrical bearing mounting portion 1 b integrally protruding from the housing 1 is formed.
A cylindrical fixed shaft 2 constituting a dynamic air bearing is fixed to the inner peripheral side of the bearing mounting portion 1b. On the cylindrical surface of the fixed shaft 2, a herringbone-shaped groove 2a for generating air dynamic pressure is formed in the circumferential direction. The rotating body 3, which is a rotating polygon mirror, has a central through hole, and a rotating sleeve 15 is fitted in the central through hole. Rotating sleeve 1
5 also has a central through hole, which fits outside the fixed shaft 2, and a bearing gap is created between the peripheral surface of the through hole and the outer peripheral surface of the fixed shaft 2. When the rotating body 3 starts rotating, the air pressure in the bearing gap formed between the rotating sleeve 15 and the fixed shaft 2 increases, and the rotating sleeve 15 and the rotating body 3 integrated therewith are brought into non-contact with the fixed shaft 2. It is supported in the radial direction (radial direction).

A fixed portion 5 of a magnetic attracting type bearing is fixed inside the fixed shaft 2. The fixed part 5 of the attraction type magnetic bearing is
The cap member 6 and the stopper 7 are press-fitted and fixed to the inner cylindrical portion of the fixed shaft 2 so as to be sandwiched and fixed in the axial direction. The central part of the cap member 6 attenuates vertical vibration using viscous resistance when air passes through φ0.2 to φ0.2.
Micro holes of about 0.5 are formed. Cap member 6
Both the stopper 7 and the stopper 7 are made of a non-magnetic material such as a stainless steel plate.

The fixed portion 5 of the attraction type magnetic bearing includes a ring-shaped permanent magnet 8 magnetized to two poles in the rotation axis direction and a ferromagnetic member having a center circle smaller than the inner diameter of the ring-shaped permanent magnet 8. Similarly, a first fixed yoke plate 9 made of a material and a second fixed yoke plate 10 made of a ferromagnetic material having a center circle smaller than the inner diameter of the ring-shaped permanent magnet 8 are formed. First fixed yoke plate 9 and second fixed yoke plate 1
Numeral 0 sandwiches the ring-shaped permanent magnet 8 in the axial direction, and is disposed and fixed such that the center circle of the first fixed yoke plate 9 and the center circle of the second fixed yoke plate 10 are coaxial with the rotation center axis. Have been. The material of the ring-shaped permanent magnet 8 is not particularly limited. For example, a rare-earth permanent magnet may be used.
Steel plates are used for the fixed yoke plates 9 and 10.
Non-magnetic material such as ceramic or aluminum alloy is used for the fixed shaft 2.

On the upper surface of the housing 1, there is disposed a printed circuit board 11 having a hole formed substantially in the center. The printed circuit board 11, the spacer 12, and the stator core 13 around which the motor winding 13a is wound are fitted in order on the outer peripheral side of the bearing mounting portion 1b of the housing 1, and the tip of the bearing mounting portion 1b is swaged (plastic deformation). Then, the three parts are sandwiched and fixed.

The motor system is a radial gap outer rotor type brushless motor. That is, a rotor housing portion integrally formed in a cup shape protruding below the light reflection surface 16a of the rotating body 3, a cylindrical rotor magnet 14 attached to the inner peripheral side of the rotor housing portion, and a rotor magnet 14, a stator core 13 fixed inside and a motor winding 13a wound on the stator core 13. The outer peripheral surface of the stator core 13 and the inner peripheral surface of the rotor magnet 14 are perpendicular to the rotation axis. Facing.

The rotating body 3 is mainly composed of a metal outer peripheral member 16 mainly composed of aluminum, has a center through hole, and a ceramic rotating sleeve 15 is inserted into the center through hole. It is shrink-fitted and fixed over the entire axial length. The outer peripheral member 16 is integrally formed with a mirror-finished light reflecting surface 16a. A plurality of light reflecting surfaces 16a are formed at equal intervals in the circumferential direction. A rotor magnet 14 for a motor is fixed to the lower inner peripheral surface of the outer peripheral member 16 by bonding or press fitting.

The outer peripheral member 16 is formed with the through hole larger than the diameter of the fixed shaft 2 constituting the dynamic pressure bearing.
The outer peripheral member 16 has the rotating sleeve 15 fixed thereto by shrink fitting as described above. The center through hole of the rotating sleeve 15 is also slightly larger than the diameter of the fixed shaft 2. In this through-hole, when the light reflecting surface 16a is processed by the above-described processing method using the above-mentioned rotary polygon mirror processing device, the tip of the mandrel is made to penetrate, and the rotating sleeve 15 is formed at the expanded portion of the mandrel. Hold the dynamic bearing surface. In this state, the rotating body 3 is processed to form the light reflecting surface 16a and to mirror-process the light reflecting surface 16a.

The components constituting the mirror surface and the dynamic pressure bearing may be separate components. In this case, it is possible to reduce the transmission of the deformation stress to the mirror surface when the dynamic pressure bearing surface is held by the hydraulic expansion type holding means, and to improve the mirror surface accuracy after the mirror surface processing. it can. Further, the material of the members constituting the dynamic pressure bearing portion may be made of ceramic. Ceramics are very hard and hard to be scratched, and have a large Young's modulus. The subsequent mirror surface accuracy can be made high.

FIG. 8 shows the rotating sleeve 15 and the light reflecting surface 16.
FIG. 7A is a diagram illustrating an axial positional relationship of a circumferential groove 16b described later, that is, an axial overlapping relationship. In FIG.
A circumferential groove 16b is formed between the outer peripheral member 16 and the rotary sleeve 15 so as to be concentric with the inscribed circle of the rotary polygon mirror having a plurality of light reflecting surfaces 16a. The circumferential groove 16b is the light reflecting surface 1
6a and the rotating sleeve 15 are formed so that their positions in the axial direction overlap (the "axial direction" means the vertical direction in the drawing). When the temperature of the rotating body 3 rises due to high-speed rotation, the linear expansion coefficient of the ceramic rotary sleeve 15 is smaller than the linear expansion coefficient of the outer peripheral member 16. Slight deformation occurs. However, since the circumferential groove 16b is formed so that the light reflecting surface 16a and the rotating sleeve 15 are overlapped with each other in the axial direction, the compressive stress due to shrink fit is blocked by the circumferential groove 16b and does not reach the light reflecting surface 16a. Even if the temperature of the rotating body 3 changes, the light reflecting surface 16a is not distorted, and a highly accurate flat surface is maintained.

A closing member 17 having a linear expansion coefficient substantially equal to that of the outer peripheral member 16 is fixed to the upper end of the through hole of the outer peripheral member 16 by press fitting. The closing member 17 has a disk shape. A thin cylindrical portion 16c is formed around an upper end of the outer peripheral member 16 around a portion where the closing member 17 is press-fitted and fixed. The thin cylindrical portion 16c is a stress absorbing portion that absorbs stress caused by press-fitting of the closing member 17. The outer diameter of the press-fitting portion of the closing member 17 is 2 times larger than the inner diameter of the press-fitting portion of the outer peripheral member 16.
It is formed to be as large as about 0 to 60 μm. Therefore, when the closing member 17 is press-fitted, the thin cylindrical portion 16c of the outer peripheral member 16 is deformed so as to expand outward. Closing member 17
When the thin cylindrical portion 16c is deformed outward at the time of press-fitting,
Stress due to press-fitting of the closing member 17 transmitted to the light reflecting surface 16a is reduced. As a result, even after the press-fitting of the closing member 17, the light reflecting surface 16a maintains a highly accurate flat surface. The thin cylindrical portion 16c has an outer diameter less than or equal to 1.2 times the inner diameter (press-fitting diameter), and by reducing the thickness of the press-fitting portion, absorbs the stress caused by press-fitting of the closing member 17 and provides a light reflecting surface. The effect of preventing the distortion of 16a is obtained. If the thickness of the thin cylindrical portion 16c is further reduced and the outer diameter is formed to be 1.1 times or less the inner diameter (press-fit diameter), the effect of preventing the light reflecting surface 16a from being distorted can be enhanced.

Deformation due to press-fitting of the thin cylindrical portion 16c serving as a stress absorbing portion includes plastic deformation and elastic deformation. When the elastic force in the radial direction is exerted by the elastic deformation, the closing member 17 is deformed.
Has been fixed. The material of the outer peripheral member 16 and the material of the closing member 17 are materials having substantially equal linear expansion coefficients.
Since the outer peripheral member 16 and the closing member 17 expand and contract in the same manner due to the temperature change, the fastening portion does not loosen, and the balance of the rotating body 3 is not lost due to the temperature change, and the vibration does not increase.

The thin cylindrical portion 16 at the upper end of the outer peripheral member 16
It is also possible to press-fit or shrink-fit a closing member having a shape different from the shape of the closing member 17 into the outer diameter c. However, as in the first embodiment, the press-fitting into the inner diameter of the thin cylindrical portion 16c fixes the closing member 17 without loosening at a high temperature. This is a ceramic rotating sleeve 15
Is 1/1 of the linear expansion coefficient of the metal outer peripheral member 16.
Since it is 3 or less, the amount of expansion of the outer diameter of the rotating sleeve 15 at high temperature is small, and the amount of expansion of the inner diameter of the shrink fit portion of the outer peripheral member 16 is also smaller than usual. The inner diameter expansion amount of the press-fitting part is also smaller than usual,
This is because the fixing force of the closing member 17 increases at a high temperature.

As shown in FIGS. 3, 6, and 7, a rotating portion 18 of a suction type magnetic bearing is arranged and fixed to the closing member 17. An outer cylindrical surface that forms a magnetic gap between the center circle of the first fixed yoke plate 9 and the center circle of the second fixed yoke plate 10 is formed in the rotating portion 18 of the attraction type magnetic bearing. The cylindrical surface is arranged so as to be coaxial with the rotation center axis. For the rotating part 18 of the attraction type magnetic bearing, a permanent magnet or a ferromagnetic material of steel is used.

In FIG. 3, the upper end of the through hole of the outer peripheral member 16 is closed by the closing member 17 so that the rotating body 3 is closed.
When the fixed shaft 2 and the fixed shaft 2 are assembled, a substantially closed space 3a is formed between the upper end of the fixed shaft and the rotating body 3. The air in the substantially closed space 3a is formed in
The vibration damping effect in the axial direction can be obtained by viscous resistance of air when entering and exiting the 0.5 micro hole.

The upper end of the outer peripheral member 16 is
The through hole of the outer peripheral member 16 including the protruding portion and the protruding portion is formed to be equal to or larger than the outer diameter of the rotating sleeve 15. Therefore, the outer peripheral member 16 and the rotating sleeve 15
No processing oil remains during the rotation, and the processing oil does not seep out due to the rotation.

The through hole of the upper end protruding portion 16c of the outer peripheral member 16 has the same diameter as the outer diameter of the rotating sleeve 15, that is,
By using the same diameter as the shrink fit diameter and using the extended portion of the shrink fit diameter as the inner diameter of the press-fitting portion of the closing member 17, the displacement of the center axis of the closing member 17 with respect to the rotating portion 18 can be minimized, The balance correction amount is reduced, and the correction work is facilitated. Also, dimensional management such as component inspection becomes easy.

The circumferential groove 16b of the outer peripheral member 16 is used as a groove for correcting the balance of the rotating body 3, and is provided at two upper and lower positions of the rotating body 3 so that unbalanced vibration is at a very small level. The balance correction is performed on the correction surfaces 16b and 14a. Since the circumferential groove 16b for removing the compressive stress of shrink fit is used as a groove for correcting the balance,
There is no need to separately provide a groove for correcting the balance.

3 and 5, above the housing 1 and the printed circuit board 11, a cover 19 whose inside is cut out so as to surround the rotating body 3 is fixed to the housing 1 with screws. The cover 19 is provided with an opening for inputting and outputting laser light, and the glass window 20 is sealed with a double-sided tape or an adhesive. An elastic seal member 21 is arranged and compressed between the cover 19 and the printed circuit board 11 to block the space in which the rotating body 3 is arranged from the outside and to seal the space in which the rotating body 3 is arranged. ing.

As shown in FIG. 4, a printed circuit board 11 is provided with a circuit element non-mounting portion 11e.
If the elastic seal member 21 is disposed at 1e and compressed, the sealing effect is enhanced. In this way, by disposing the rotating body 3 in the closed space, the amount of air stirred by the rotating polygon mirror is reduced, windage loss is reduced, and the current flowing through the driving element is reduced.
Unnecessary power consumption is suppressed. The noise level is reduced by confining the wind noise of the rotating polygon mirror.

The printed circuit board 11 is provided with a drive circuit, which is pattern-wired with the motor winding 13a and the hall element 11a, and sequentially switches energization to the motor winding 13a in accordance with a position detection signal of the hall element 11a. The rotary body 3 is driven to rotate, and is controlled at a constant speed. The printed board 11 is a single-sided metal board, and the rotor magnet 14
Circuit elements 11a, 11b, 11c, 11
d and the like are mounted, and the back surface is fixed in close contact with the housing 1 made of an aluminum alloy. As a result, the heat capacity of the circuit element against the heat generated by the circuit element such as the drive element 11b is increased, and the heat radiation efficiency is improved, so that a small and low-cost circuit element can be used. In addition, the cost of the printed circuit board 11 can be reduced by using a single-sided metal substrate that does not require through-hole processing.

Further, in the illustrated embodiment, the driving element 1
Circuit elements such as 1b are arranged in a closed space where the rotating body 3 is arranged. Since the air is agitated by the rotation of the rotating body 3 in the closed space, the temperature of the closed space becomes substantially uniform, and the heat generated by the circuit elements can be dispersed and radiated. As a result, the temperature rise of the circuit element can be suppressed, and the reliability can be improved.

A portion of the printed circuit board 11 is exposed from between the housing 1 and the cover 19, and a connector 11d for input / output signals and a drive power supply is mounted on the exposed portion. By arranging the connector 11d for input / output signals and driving power above the mounting reference plane of the housing 1, the harness can be mounted even after the optical deflector has been mounted, and the workability is improved by insertion from above. I have.

The closed type optical deflector having the above-described structure is provided with a cover 19.
In a small and compact form,
There is an advantage that characteristics such as uneven rotation and noise at high speed rotation can be easily guaranteed, and inspection is easy.

Further, the hermetically sealed optical deflector having the above structure is used by being mounted on an aluminum die-cast optical housing provided with a surface which is in close contact with the mounting reference surface of the housing 1, so that the optical deflector accompanying high-speed rotation can be obtained. Against the fever of
A heat radiation path from the metal substrate to the housing and further to the optical housing can be secured. As a result, the temperature rise of the driving element 11b of the optical deflector and the like can be kept low, and the optical deflector can be used in a state where the reliability is secured.

Embodiment 2 FIG. 9 shows a rotary polygon mirror according to Embodiment 2 of the present invention. This embodiment is different from the rotary polygon mirror according to the first embodiment only in the configuration of a rotating body 30 which is a rotary polygon mirror, and the other configurations are the same as those in the first embodiment. Omitted. In FIG. 9, the rotating body 30 is made of a metal member mainly composed of aluminum, and a mirror portion 31a is integrally formed outside the dynamic pressure air bearing portion 31b. A magnet holding portion 31c is formed below the rotating body 30, and the rotor magnet 14 for the motor is fixed by bonding or press fitting. A surface treatment film having high wear resistance or lubricity is formed on the dynamic pressure bearing surface of the dynamic pressure air bearing portion 31b to suppress contact wear when starting and stopping. A circumferential groove 31d as a stress removing portion is formed between the dynamic pressure bearing surface and the light reflecting surface 31a.
The metal member has a center through hole larger than the dynamic pressure bearing diameter. The light reflecting surface 31a is processed by the above-described rotary polygon mirror processing method using the above-described rotary polygon mirror processing apparatus. After the processing, the closing member 32 and the rotating portion 18 of the attraction type magnetic bearing are arranged and fixed in the through hole.

The light reflecting surface 31a is processed by the above-described rotary polygon mirror processing method using the above-described rotary polygon mirror processing apparatus. At that time, since the rotating body 30 has a central through-hole larger than the dynamic pressure bearing diameter, the mandrel is passed through the through-hole from its tip, and the expanded portion of the mandrel is
The peripheral surface of the through hole is held, or a rotary sleeve is fitted into the through hole by press fitting or the like, and the dynamic pressure bearing surface formed on the inner periphery of the rotary sleeve is held. By processing a predetermined portion of the rotating body 30 in this state, the light reflecting surface 31a can be formed.

In the rotary polygon mirror according to the second embodiment,
A circumferential groove 31d, which is a stress removing portion, is formed between the dynamic pressure bearing surface 31b and the light reflecting surface 31a. Therefore, it is possible to reduce the transmission of the deformation stress to the light reflecting surface 31a when the dynamic pressure bearing surface 31b is held by the above-described mandrel or the like, which is a hydraulic expansion type holding means.
The mirror surface accuracy after mirror surface processing can be made high.

Although the embodiments according to the present invention have been described above, the present invention relates to a processing apparatus, a processing method, and a rotary polygon mirror of a rotary polygon mirror having an integrated dynamic pressure bearing. Although the dynamic pressure bearing is an air dynamic pressure bearing in the illustrated embodiment, it may be an oil dynamic pressure bearing or another fluid bearing, or a fluid bearing if the high-speed rotation with high accuracy is obtained. Need not be. Further, the configuration of the motor unit is not limited to the illustrated embodiment.

[0061]

According to the first aspect of the present invention, the rotary polygon mirror is held by the hydraulic expansion type holding means with a uniform holding force over the entire length and the entire circumference of the bearing surface of the dynamic pressure bearing. By processing the mirror surface, all mirror surfaces are formed at a fixed angle with respect to the rotation center axis of the rotating polygon mirror, and the angle accuracy is high, and the flatness accuracy is high. Can be provided.

According to the second aspect of the present invention, the mirror surface of the rotating polygon mirror is held by the hydraulic expansion type holding means with a uniform holding force over the entire length and the entire circumference of the bearing surface of the dynamic pressure bearing. By processing, all mirror surfaces are formed at a fixed angle with respect to the rotation center axis of the rotating polygon mirror, and the angular accuracy is high accuracy,
It is possible to provide a method for processing a rotating polygon mirror capable of mirror processing with high flatness accuracy.

According to the third aspect of the present invention, the mirror surface of the rotary polygon mirror is held by the hydraulic expansion type holding means with a uniform holding force over the entire length and the entire circumference of the bearing surface of the dynamic pressure bearing. By processing, all mirror surfaces are formed at a fixed angle with respect to the rotation center axis of the rotating polygon mirror, and the angular accuracy is high accuracy,
It is possible to provide a rotating polygon mirror capable of mirror processing with high flatness accuracy.

According to the fourth aspect of the present invention, when the dynamic pressure bearing surface is held by the hydraulic expansion type holding means by separating the components constituting the mirror surface portion and the dynamic pressure bearing portion as separate components and separating them. It is possible to provide a rotating polygon mirror in which the deformation stress is reduced from being transmitted to the mirror surface and the mirror surface accuracy after the mirror surface processing is high.

According to the fifth aspect of the present invention, since the surface treatment film is formed on the metal member and the dynamic pressure bearing surface is formed on the surface treatment film, the dynamic pressure bearing surface of the dynamic pressure air bearing portion is formed. It is possible to provide a rotary polygon mirror that has improved wear resistance or lubricity and can suppress contact wear when starting and stopping.

According to the sixth, seventh and eighth aspects of the invention, it is possible to reduce the transmission of the deformation stress when the dynamic pressure bearing surface is held by the hydraulic expansion type holding means to the mirror surface. In addition, it is possible to provide a rotating polygon mirror having high mirror accuracy after mirror processing.

According to the ninth aspect of the present invention, it is possible to provide a rotary polygon mirror having a high damping effect on vertical vibration.

According to the tenth aspect of the present invention, there is provided a rotary polygonal mirror having a high damping effect on vertical vibration, wherein the thin-walled cylindrical portion serves as a stress absorbing portion due to press-fitting of the closing member, and the deformation stress caused by press-fitting of the closing member. Is transmitted to a mirror surface, and a rotating polygon mirror with high mirror surface accuracy after mirror surface processing can be provided.

[Brief description of the drawings]

FIG. 1 is a partially sectional front view showing an embodiment of a rotary polygon mirror processing method and a rotary polygon mirror processing apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view showing an example of a hydraulic expansion type holding means used in the rotary polygon mirror processing apparatus.

FIG. 3 is a sectional view showing an example of a rotary polygon mirror device having a rotary polygon mirror according to the present invention.

FIG. 4 is a plan view showing the rotary polygon mirror with the cover removed.

FIG. 5 is an exploded perspective view showing an example of a rotary polygon mirror device having the rotary polygon mirror according to the present invention.

FIG. 6 is an exploded perspective view showing a rotary polygon mirror portion of the rotary polygon mirror device.

FIG. 7 is a longitudinal sectional view of a part of the rotary polygon mirror;

FIG. 8 is a longitudinal sectional view showing a positional relationship in the axial direction of a light reflecting surface, a circumferential groove, and a sleeve of the rotary polygon mirror.

FIG. 9 is a longitudinal sectional view showing another embodiment of the rotary polygon mirror according to the present invention, which has a rotating portion of a magnetic bearing.

FIG. 10 is a longitudinal sectional view showing an embodiment of the rotary polygon mirror;

[Explanation of symbols]

 Reference Signs List 3 Rotating body 15 Sleeve 16 Outer peripheral member as metal member 16a Light reflecting surface 16b Circular groove 16c Thin cylindrical portion 17 Closing member 103 Mandrel 103b as holding means 103b Expansion portion 105 Metal member

Claims (10)

[Claims] In a rotary polygon mirror processing apparatus for holding a metal member as a workpiece by a holding means and performing mirror finishing, the holding means includes a dynamic pressure formed integrally with the metal member. A rotary polygon mirror processing apparatus, characterized in that it is a hydraulic expansion type holding means for holding a dynamic pressure bearing surface of a bearing. 2. A dynamic pressure bearing surface of a dynamic pressure bearing formed integrally with a metal member to be processed is held by a hydraulic expansion type holding means provided in a rotary polygon mirror processing apparatus. A rotary polygon mirror processing method, wherein mirror processing is performed on the workpiece in a state. 3. A rotary polygon mirror in which a dynamic pressure bearing surface is integrally formed on a metal member and a plurality of mirror surfaces are formed at equal intervals in a circumferential direction. For inserting a pressure bearing, it is almost the same as the diameter of the dynamic pressure bearing, or
A rotary polygon mirror comprising a through hole larger than the diameter of the dynamic pressure bearing, and wherein the dynamic pressure bearing surface also serves as a holding portion held by holding means for forming a mirror surface on the metal member. . 4. The rotary polygon mirror according to claim 3, wherein a sleeve is fixed inside the metal member, and a dynamic pressure bearing surface is formed in a through hole of the sleeve. 5. The rotary polygon mirror according to claim 3, wherein a surface treatment film is formed on the metal member, and a dynamic pressure bearing surface is formed on the surface treatment film. 6. The rotary polygon mirror according to claim 5, wherein the metal member has a stress removing portion for preventing a deformation stress when the dynamic pressure bearing surface is held by the holding means from being transmitted to the mirror surface. A rotating polygon mirror that has been formed. 7. The rotary polygon mirror according to claim 6, wherein the stress removing portion is a circumferential groove formed between the dynamic pressure bearing surface and the mirror surface. 8. The rotary polygon mirror according to claim 7, wherein the circumferential groove has an axial position overlapping an axial position of the dynamic pressure bearing surface and the mirror surface. 9. The rotary polygon mirror according to claim 3, wherein one end of the through-hole is closed by a closing member. 10. The rotating polygon mirror according to claim 9, wherein
The metal member is a rotary polygon mirror in which one end of a through hole into which the closing member is fitted is a thin cylinder.