JP2000019447A - Polygon mirror scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the assembly man-hour of a polygon mirror scanner and to improve the reliability. SOLUTION: This polygon mirror scanner 1 has a polygon mirror 2 provided with a deflecting and reflecting surface reflecting a laser beam on its side surface part and a shaft hole 2c formed in the center part, and a motor equipped with a rotary shaft 3 inserted and fitted into the shaft hole 2c and rotating the polygon mirror 2. A centripetal elastic member 6 being a concentric supporting means for aligning the center axis of the rotary shaft 3 with that of the shaft hole 2c when the rotary shaft 3 is inserted and fit in the shaft hole 2c is installed between the shaft hole 2c and the rotary shaft 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on a laser beam printer (hereinafter referred to as "LBP") or the like,
The present invention relates to a polygon mirror scanner that deflects and scans a laser beam.

[0002]

FIG. 9 is a sectional view showing a conventional polygon mirror scanner, and FIG. 10 is a plan view showing a polygon mirror and the like of the conventional polygon mirror scanner shown in FIG.

A conventional polygon mirror scanner 101 is
A polygon mirror 102 provided on a side surface with a deflecting / reflecting surface 102a for reflecting a laser beam emitted from a laser light source (not shown); and a spindle motor (not shown) provided with a rotating shaft 103 for rotating the polygon mirror 102. Having. A flange 104 is fixed to the rotating shaft 103 by caulking, and a rotor yoke 105 is fixed to the flange 104 by caulking. That is, the rotating shaft 103
, A rotor yoke 105 is fixed via a flange 104. A magnet 109 is provided on the inner peripheral surface of the rotor yoke 105.

The polygon mirror 102 is pressed against the flange 104 by a wave spring 106 provided between the G ring 108 locked on the rotating shaft 103 and the polygon mirror 104, and the reference surface 102 b of the polygon mirror 102 is It is pressed against the upper surface. The upper surface of the flange 104 is provided perpendicular to the axial direction of the rotating shaft 103. Thereby, the polygon mirror 10
Reference numeral 2 denotes a reference surface 102b that is arranged perpendicular to the rotation axis 103. Note that a washer 107 is provided between the G ring 108 and the wave spring 106.

In recent years, with the increase in speed and precision of LBP, a polygon mirror scanner has been
Higher performance such as high-speed rotation of 0 rpm or more and low-speed unevenness has been demanded. In order to prevent vibration from occurring when the polygon mirror is rotated at high speed, the balance of the moment of inertia (inertia balance) is 3 mg · cm.
It is required that: However, in the conventional polygon mirror scanner 101 described above, when the polygon mirror 102 is fixed to the rotation shaft 103, the distance between the shaft hole 102c of the polygon mirror 102 and the rotation shaft 103 is equal to the clearance between the two. The coaxiality varies. Therefore, in the conventional polygon mirror scanner 101, in order to keep the inertia balance at 3 mg · cm or less, the upper surface of the polygon mirror 102 and the rotor yoke 1
A weight 110 for inertia balance adjustment is attached to the outer edge of 05. Weight 1 for inertia balance adjustment
Reference numeral 10 is fixed to each part by an adhesive.

[0006] According to the conventional polygon mirror scanner 101 configured as described above, the laser beam emitted from the laser light source to the polygon mirror 102 is rotated by the rotation axis 1.
The light is reflected by the deflecting / reflecting surface 102a of the polygon mirror 102 which rotates around the center 03, and is deflected and scanned. The laser beam that has been deflected and scanned scans a photosensitive drum provided in the LBP, whereby an electrostatic latent image is formed on the surface of the photosensitive drum.

[0007]

However, as described above, in the above-described prior art, when the polygon mirror is fixed to the rotating shaft, the inertia is reduced in order to suppress the variation in the coaxiality between the two. There is a problem that the balance needs to be adjusted and the number of man-hours for assembling the polygon mirror scanner increases.

[0008] Further, due to a change in the use environment of the polygon mirror scanner or a change with time, the position of the polygon mirror with respect to the rotation axis is shifted, and the adhesive for fixing the inertia balance adjusting weight is peeled off, so that the inertia unbalance is caused. , The rotational accuracy is deteriorated, the vibration is increased, and there is a possibility that the problem of deteriorating the LBP printing quality may occur.

Accordingly, an object of the present invention is to provide a polygon mirror scanner capable of reducing the number of assembly steps and improving reliability.

[0010]

In order to achieve the above object, a polygon mirror scanner according to the present invention is provided with a deflecting reflection surface for reflecting a laser beam on a side surface portion and a shaft hole formed in a center portion. A polygon mirror rotated about the shaft hole, and a motor inserted into the shaft hole and provided with a rotation shaft for rotating the polygon mirror; rotating the polygon mirror; In the polygon mirror scanner that deflects and scans the laser beam by reflecting the laser beam, the rotation between the shaft hole and the rotation shaft is performed when the rotation shaft is inserted into the shaft hole. Concentric support means for aligning the center axis of the shaft with the center axis of the shaft hole is provided.

This eliminates the need to adjust the inertia balance after the polygon mirror is mounted on the rotating shaft, so that the inertia balance adjusting weight is placed on the polygon mirror, and a groove for filling the adhesive is formed on the upper surface of the polygon mirror. It becomes unnecessary to do it. As a result, the number of assembling steps of the polygon mirror scanner is reduced, and the reliability with respect to aging is improved.

Further, the concentric support means may be formed of an elastic member and provided on an outer periphery of the rotary shaft, and an outer diameter of the concentric support means may be larger than an inner diameter of the shaft hole.

Further, at least three projections may be formed on the outer periphery of the concentric support means so as to be symmetrical to each other with respect to the center axis of the concentric support means.

In addition, it is preferable that the concentric support means is fixed to the shaft hole of the polygon mirror with an adhesive.

Further, the concentric support means may be formed of an elastic member and provided on an inner periphery of the shaft hole, and an inner diameter of the concentric support means may be formed smaller than an outer diameter of the rotary shaft.

Further, at least three projections may be formed on the inner periphery of the concentric support means so as to be symmetrical to each other with respect to the center axis of the concentric support means.

In addition, it is preferable that the rotating shaft is fixed to the inner periphery of the concentric support means with an adhesive.

Further, the rotating shaft is provided with a flange member having a plane portion perpendicular to the axial direction of the rotating shaft,
The lower surface of the polygon mirror is configured to be in contact with the flat surface, so that the polygon mirror is arranged perpendicular to the axial direction of the rotation axis, thereby suppressing vibration generated when the polygon mirror is rotated. At the same time, the direction of reflection of the laser beam reflected by the deflecting reflection surface becomes constant.

Further, by providing a pressing means for pressing the lower surface portion of the polygon mirror against the flat portion of the flange member, when the inertia of the polygon mirror is large, or when the polygon mirror operates at high speed, Also in the case where the polygon mirror is rotated, it is possible to prevent the polygon mirror from falling off the rotation axis.

Further, the concentric support means and the flange member may be integrally formed.

[0021]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a sectional view showing a polygon mirror scanner according to a first embodiment of the present invention, and FIG.
FIG. 2 is a plan view showing a polygon mirror and the like of the polygon mirror scanner shown in FIG.

Here, the respective configurations of the polygon mirror 2, the deflecting / reflecting surface 2a, the rotating shaft 3, the flange 4, the rotor yoke 5, and the magnet 7 in the polygon mirror scanner 1 of the present embodiment shown in FIG. Since the configuration is the same as that of the conventional polygon mirror scanner 101 shown, detailed description is omitted.

In the present embodiment, a centripetal elastic member 6 which is a concentric supporting means made of an elastic member and having six convex portions 6a formed on the outer peripheral portion is insert-molded on the rotating shaft 3. Each convex portion 6 a is formed symmetrically with respect to the center axis of the centripetal elastic member 6. Also, the centripetal elastic member 6
Is slightly larger than the inner diameter of the shaft hole 2c formed at the center of the polygon mirror 2. Thereby, the rotating shaft 3 is inserted into the shaft hole 2c of the polygon mirror 2,
When the centripetal elastic member 6 is inserted into the shaft hole 2c, the two are fixed to each other with the center axis of the rotating shaft 3 and the center axis of the polygon mirror 2 aligned. The centripetal elastic member 6 has such a hardness that the rigidity of the rotating body composed of the polygon mirror 2 and the rotating shaft 3 is not impaired even when the polygon mirror 2 is rotated.

The polygon mirror 2 has a lower reference surface 2 b pressed against the upper surface of the flange 4, which is a plane perpendicular to the axial direction of the rotary shaft 3. It is arranged perpendicularly to it. Thereby, the vibration generated when the polygon mirror 2 is rotated can be suppressed, and the reflection direction of the laser beam reflected by the deflecting / reflecting surface 2a can be made constant.

In order to maintain the coaxiality and perpendicularity of the polygon mirror 2 with respect to the rotation axis 3, an adhesive injection port 8 formed in a gap between the shaft hole 2 c of the polygon mirror 2 and the elastic member 6 for centripetal movement. , An adhesive (not shown) is injected.
The adhesive is applied to the concave portions of the centripetal elastic member 6 and the polygon mirror 2.
Flows into the gap between the shaft hole 2c and the inner peripheral surface, whereby the rotating shaft 3 and the polygon mirror 2 are firmly fixed. An adhesive pool 6b is provided below the centrifugal elastic member 6 to retain the adhesive before curing in the fitting portion between the two, and the adhesive flows out to the flange 4 and the rotor yoke 5. Has been prevented. As a result, even if the amount of the adhesive used is small, the rotating shaft 3 and the polygon mirror 2 can be firmly fixed.

According to the polygon mirror scanner 1 configured as described above, the laser beam emitted from the laser light source to the polygon mirror 2 is reflected by the deflecting / reflecting surface 2a of the rotating polygon mirror 2 and is deflectively scanned. . The deflection-scanned laser beam scans on a photosensitive drum (not shown) provided in an LBP (not shown),
As a result, an electrostatic latent image is formed on the surface of the photosensitive drum.

As described above, in this embodiment,
By inserting the centripetal elastic member 6 into the shaft hole 2c of the polygon mirror 2, the two are fixed to each other in a state where the center axis of the rotating shaft 3 and the center axis of the polygon mirror 2 coincide with each other. There is no need to adjust the inertia balance after attaching the polygon mirror 2 to the mirror, and there is no need for an inertia balance adjustment weight or a groove for filling the adhesive formed on the upper surface of the polygon mirror as used in the prior art. It can be. Therefore, the number of assembling steps of the polygon mirror scanner 1 can be reduced, and the reliability with respect to aging can be improved.

In the present embodiment, the centering elastic member 6 having six convex portions 6a formed on the outer peripheral portion has been described as an example. However, the number of convex portions formed on the outer peripheral portion is not limited to six. It is sufficient that at least three projections are formed.

(Second Embodiment) FIG. 3 is a sectional view showing a polygon mirror scanner according to a second embodiment of the present invention.
4 is a plan view showing a polygon mirror and the like of the polygon mirror scanner shown in FIG.

Here, the respective configurations of the polygon mirror 12, the deflecting / reflecting surface 12a, the rotating shaft 13, the flange 14, the rotor yoke 15, and the magnet 17 in the polygon mirror scanner 11 of the present embodiment shown in FIG. Since it is the same as the polygon mirror scanner 1 shown, a detailed description is omitted.

In this embodiment, a centering elastic member 16 which is a concentric supporting means which is formed of an elastic member and has six convex portions 16a formed on an inner peripheral portion thereof is provided in a shaft hole formed in the center of the polygon mirror 12. 12c is insert-molded. Each convex part 16a is formed symmetrically with respect to the central axis of the elastic member 16 for centripetal movement. In addition, the centrifugal elastic member 16
Is provided slightly smaller than the outer diameter of the rotating shaft 13. As a result, the rotating shaft 13 is moved to the centering elastic member 16.
Are fixed to each other with the center axis of the rotating shaft 13 and the center axis of the polygon mirror 12 aligned. In addition, the elastic member 16 for centripetal movement is
Is rotated, the polygon mirror 12 and the rotation axis 1 are rotated.
3 has such a hardness that the rigidity of the rotating body is not impaired.

Further, the polygon mirror 12 has a reference surface 12 b on the lower surface thereof pressed against the upper surface of the flange 14 which is a plane perpendicular to the axial direction of the rotary shaft 13, so that the polygon mirror 12 can move in the axial direction of the rotary shaft 13. It is arranged perpendicularly to it. This suppresses the vibration generated when the polygon mirror 12 is rotated, and the deflection reflecting surface 12a.
The direction of reflection of the laser beam reflected by the laser beam can be made constant.

Also in this embodiment, in order to maintain the coaxiality and perpendicularity of the polygon mirror 12 with respect to the rotation shaft 13, the gap is formed between the shaft hole 12c of the polygon mirror 12 and the centering elastic member 16. An adhesive (not shown) is injected from the adhesive injection port 18. The adhesive flows into a gap between the concave portion of the centripetal elastic member 16 and the outer peripheral surface of the rotating shaft 13, whereby the rotating shaft 13 and the polygon mirror 12 are firmly fixed. An adhesive pool 16b is provided below the centrifugal elastic member 16 to retain the adhesive before curing in the fitting portion between the two, and the adhesive flows out to the flange 14 and the rotor yoke 15. Has been prevented. As a result, even if the amount of adhesive used is small,
The rotation shaft 13 and the polygon mirror 12 can be firmly fixed.

In the polygon mirror scanner 11 of this embodiment, the polygon mirror 12 is
Is reflected by the deflecting reflection surface 12a of the rotating polygon mirror 12, and is deflectively scanned. The laser beam that has been deflected and scanned scans a photosensitive drum (not shown) provided in an LBP (not shown), whereby an electrostatic latent image is formed on the surface of the photosensitive drum.

As described above, in this embodiment,
Elastic member 1 for centripetal molding integrally formed with polygon mirror 12
By inserting the rotation shaft 13 into the shaft 6, the two are fixed to each other in a state where the center axis of the rotation shaft 13 coincides with the center axis of the polygon mirror 12, so that after the polygon mirror 12 is mounted on the rotation shaft 13, It is not necessary to adjust the inertia balance, and the weight for inertia balance adjustment and the groove for filling the adhesive formed on the upper surface of the polygon mirror as used in the prior art can be eliminated. Therefore, the number of man-hours for assembling the polygon mirror scanner 11 can be reduced, and the reliability against aging can be improved.

In the present embodiment, the centering elastic member 16 having six convex portions 16a formed on the inner peripheral portion has been described as an example. However, the number of convex portions formed on the inner peripheral portion is not limited to six. Not
It is sufficient that at least three projections are formed.

(Third Embodiment) FIG. 5 is a sectional view showing a polygon mirror scanner according to a third embodiment of the present invention.
6 is a plan view showing a polygon mirror and the like of the polygon mirror scanner shown in FIG.

Here, the respective configurations of the polygon mirror 22, the deflecting / reflecting surface 22a, the rotating shaft 23, the flange 24, the rotor yoke 25 and the magnet 27 in the polygon mirror scanner 21 of the present embodiment shown in FIG. Since it is the same as the polygon mirror scanner 1 shown, a detailed description is omitted.

In this embodiment, the outer diameter of the polygon mirror 2 is
The centering elastic member 26 as a concentric supporting means provided slightly larger than the inner diameter of the shaft hole 22a formed at the center of
Are insert-molded on the rotating shaft 23. As a result, when the rotating shaft 23 is inserted into the shaft hole 22c of the polygon mirror 22 and the centering elastic member 26 is inserted into the shaft hole 22c, the center axis of the rotating shaft 23 and the center axis of the polygon mirror 22 match. Both are fixed to each other in a state where they are set. In addition,
The centripetal elastic member 26 is formed of an elastic member. The elastic member has such a hardness that the rigidity of the rotating body including the polygon mirror 22 and the rotating shaft 23 is not impaired even when the polygon mirror 22 is rotated. Have.

In the polygon mirror 22, the reference surface 22b of the lower surface portion is in contact with the upper surface of the flange 24 which is a plane perpendicular to the axial direction of the rotating shaft 23. As a result, the polygon mirror 22 is arranged perpendicularly to the axial direction of the rotation shaft 23, so that the vibration generated when the polygon mirror 22 is rotated is suppressed, and the deflecting reflection surface 22a
The direction of reflection of the laser beam reflected by the laser beam can be made constant. Furthermore, the polygon mirror 22 is
The flange 24 is pressed by a pressing means constituted by a G ring 30 locked by 3 and a spring 28 provided between the G ring 30 and the polygon mirror 22. Note that a washer 29 is provided between the G ring 30 and the spring 28.

The polygon mirror scanner 21 of the present embodiment
The laser beam emitted from the laser light source to the polygon mirror 22
Is reflected by the deflecting / reflecting surface 22a, and is deflected and scanned. The deflection-scanned laser beam scans on a photosensitive drum (not shown) provided in an LBP (not shown),
As a result, an electrostatic latent image is formed on the surface of the photosensitive drum.

As described above, in this embodiment,
The centering elastic member 26 is connected to the shaft hole 22c of the polygon mirror 22.
By fixing the polygon mirror 22 to the rotating shaft 23, the inertia balance can be adjusted after the polygon mirror 22 is attached to the rotating shaft 23 because the center axis of the rotating shaft 23 and the center axis of the polygon mirror 22 are aligned with each other. This need not be performed, and the inertia balance adjusting weight and the groove for filling the adhesive formed on the upper surface of the polygon mirror as used in the related art can be eliminated. for that reason,
The man-hours for assembling the polygon mirror scanner 21 can be reduced, and the reliability over time can be improved.

Further, in the present embodiment, since the polygon mirror 22 is pressed against the flange 24 by the spring 28, even when the inertia of the polygon mirror 22 is large or when the polygon mirror 22 is rotated at a high speed, the rotating shaft is rotated. It is possible to prevent the polygon mirror 22 from falling off from the lens 23. When it is necessary to fix the rotation shaft 23 and the polygon mirror 22 more firmly, it is preferable to bond the centriped elastic member 26 and the polygon mirror 22 with an adhesive.

(Fourth Embodiment) FIG. 7 is a sectional view showing a polygon mirror scanner according to a fourth embodiment of the present invention.
8 is a plan view showing a polygon mirror and the like of the polygon mirror scanner shown in FIG.

Here, the polygon mirror 32, the deflecting / reflecting surface 32a, the rotating shaft 33, the rotor yoke 35, the magnet 37, the spring 38, the washer 39 and the G ring 4 in the polygon mirror scanner 31 of this embodiment shown in FIG.
0 are the same as those of the polygon mirror scanner 21 shown in FIG. 5 and the like, and a detailed description thereof will be omitted.

In this embodiment, the flange 34 and the centering elastic member 36, which is a concentric support member whose inner diameter is slightly smaller than the outer diameter of the rotating shaft 33, are integrated with each other, and are insert-molded on the rotating shaft 33. Have been. As a result, when the rotating shaft 33 is inserted into the centering elastic member 36, the rotating shaft 3
The two are fixed to each other in a state where the central axis of the third mirror 3 and the central axis of the polygon mirror 32 coincide with each other. Note that the centripetal elastic member 36 is formed of an elastic member, and the elastic member retains the polygon mirror 32 even when the polygon mirror 32 is rotated.
And the rotating shaft 33 have such a hardness that the rigidity of the rotating body is not impaired. The flange 34 is fixed by caulking to the rotor yoke 35.

In the polygon mirror 32, the reference surface 32 b of the lower surface portion is in contact with the upper surface of the flange 34 which is a plane perpendicular to the axial direction of the rotating shaft 33. As a result, the polygon mirror 32 is disposed perpendicularly to the axial direction of the rotating shaft 33, so that the vibration generated when the polygon mirror 32 is rotated is suppressed, and the deflecting reflection surface 32a
The direction of reflection of the laser beam reflected by the laser beam can be made constant. Furthermore, the polygon mirror 32
Pressing means constituted by a G-ring 40 locked by 3 and a spring 38 provided between the polygon mirror 32 and the G ring 40 presses the flange 34 on the flange 34.

The polygon mirror scanner 31 of the present embodiment
The laser beam emitted from the laser light source to the polygon mirror 32 also
Is reflected by the deflecting / reflecting surface 32a, and is deflectively scanned. The deflection-scanned laser beam scans on a photosensitive drum (not shown) provided in an LBP (not shown),
As a result, an electrostatic latent image is formed on the surface of the photosensitive drum.

As described above, in the present embodiment,
The centering elastic member 36 is connected to the shaft hole 32 c of the polygon mirror 32.
By fixing the polygon mirror 32 to the rotating shaft 33, the inertia balance can be adjusted after the polygon mirror 32 is attached to the rotating shaft 33 because the center axis of the rotating shaft 33 and the center axis of the polygon mirror 32 are aligned with each other. This need not be performed, and the inertia balance adjusting weight and the groove for filling the adhesive formed on the upper surface of the polygon mirror as used in the related art can be eliminated. for that reason,
The man-hours for assembling the polygon mirror scanner 31 can be reduced, and the reliability over time can be improved.

In this embodiment, the centering elastic member 3
6 and the flange 34 are provided integrally, but in such a configuration, the fixing strength between them is low. Therefore, this embodiment is suitable when the rotation speed of the polygon mirror scanner 31 at the time of use is low, when the polygon mirror 32 having a small moment of inertia is used, or when a low-end type motor is used. .

[0052]

As described above, the polygon mirror scanner of the present invention rotates between the shaft hole formed in the polygon mirror and the rotation shaft of the motor when the rotation shaft is inserted into the shaft hole. Concentric support means for aligning the center axis of the shaft with the center axis of the shaft hole eliminates the need to adjust the inertia balance after attaching the polygon mirror to the rotating shaft, thus assembling the polygon mirror scanner. The number of man-hours can be reduced, and the reliability over time can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a polygon mirror scanner of the present invention.

FIG. 2 is a plan view showing a polygon mirror and the like of the polygon mirror scanner shown in FIG.

FIG. 3 is a sectional view illustrating a polygon mirror scanner according to a second embodiment of the present invention.

4 is a plan view showing a polygon mirror and the like of the polygon mirror scanner shown in FIG.

FIG. 5 is a sectional view showing a third embodiment of the polygon mirror scanner of the present invention.

6 is a plan view showing a polygon mirror and the like of the polygon mirror scanner shown in FIG.

FIG. 7 is a sectional view showing a fourth embodiment of the polygon mirror scanner of the present invention.

FIG. 8 is a plan view showing a polygon mirror and the like of the polygon mirror scanner shown in FIG.

FIG. 9 is a sectional view showing a conventional polygon mirror scanner.

FIG. 10 is a plan view showing a polygon mirror and the like of the conventional polygon mirror scanner shown in FIG.

[Explanation of symbols]

 1, 11, 21, 31 Polygon mirror scanner 2, 12, 22, 32 Polygon mirror 2a, 12a, 22a, 32a Deflection / reflection surface 2b, 12b, 22b, 32b Reference surface 2c, 12c, 22c, 32c Shaft hole 3, 13 , 23, 33 Rotating shaft 4, 14, 24, 34 Flange 5, 15, 25, 35 Rotor yoke 6, 16, 26, 36 Centering elastic member 6a, 16a Convex portion 6b, 16b Adhesive reservoir 7, 17, 27, 37 magnet 8,18 adhesive inlet 28,38 spring 29,39 washer 30,40 G ring

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takao Atsugi 1248 Shimokage Mori, Chichibu City, Saitama Prefecture Inside Canon Electronics Co., Ltd. (72) Inventor Koichi Okichi 1248 Shimokage Mori, Chichibu City, Saitama Prefecture Canon Electronics Co., Ltd. In-house F-term (reference) 2H045 AA07 AA14 AA49 AA62

Claims (10)

[Claims] A polygon mirror having a deflecting / reflecting surface for reflecting a laser beam provided on a side surface thereof, a shaft hole formed in a center portion, and rotated around the shaft hole; And a motor provided with a rotating shaft for rotating the polygon mirror, the polygon mirror scanner rotating the polygon mirror and reflecting the laser beam on the deflection reflection surface to deflect and scan the laser beam. A concentric support between the shaft hole and the rotation shaft for aligning a center axis of the rotation shaft with a center axis of the shaft hole when the rotation shaft is inserted into the shaft hole. A polygon mirror scanner characterized by comprising means. 2. The concentric support means according to claim 1, wherein said concentric support means is formed of an elastic member and is provided on an outer periphery of said rotary shaft, and an outer diameter of said concentric support means is formed larger than an inner diameter of said shaft hole. Polygon mirror scanner. 3. The polygon mirror scanner according to claim 2, wherein at least three convex portions are formed on an outer periphery of said concentric support means so as to be symmetric with respect to a center axis of said concentric support means. 4. The polygon mirror scanner according to claim 2, wherein said concentric support means is fixed to a shaft hole of said polygon mirror with an adhesive. 5. The concentric support means comprises an elastic member and is provided on an inner periphery of the shaft hole, and an inner diameter of the concentric support means is formed smaller than an outer diameter of the rotary shaft. Polygon mirror scanner. 6. The polygon mirror scanner according to claim 5, wherein at least three projections are formed symmetrically with respect to a center axis of said concentric support means on an inner periphery of said concentric support means. 7. The method according to claim 5, wherein the rotating shaft is fixed to an inner periphery of the concentric support means with an adhesive.
Polygon mirror scanner according to the item. 8. The rotating shaft is provided with a flange member having a flat portion perpendicular to the axial direction of the rotating shaft, and a lower surface portion of the polygon mirror is in contact with the flat portion. 8. The polygon mirror scanner according to any one of items 1 to 7. 9. The polygon mirror scanner according to claim 8, further comprising pressing means for pressing a lower surface of said polygon mirror against said flat portion of said flange member. 10. The polygon mirror scanner according to claim 8, wherein said concentric support means and said flange member are integrally formed.