Assembly Method of Sleeve, Spring and Motor

Abstract

The present invention relates to an assembly method for a sleeve, a spring and an electric motor, wherein the sleeve is mounted on the rotating shaft of the electric motor, and is characterized in that in the longitudinal direction of the rotating shaft, it includes: a disc portion; a first cylindrical portion; a second cylindrical portion; a frustum of a cone portion located between the first cylindrical portion and the second cylindrical portion, the second cylindrical portion having a diameter larger than that of the frustum of a cone portion, and an annular support surface is formed on the portion of the disc portion on the side of the first cylindrical portion.

Description

[0001] This application is a divisional application of the patent application with the application number 201810222299.3, the application date of March 16, 2018, and the invention title of Multi-angle Mirror Scanner Motor. Technical Field

[0002] The present invention relates to an assembly method of a sleeve, a spring, and a motor. Background Art

[0003] In a laser writing system such as a laser printer, a polygon mirror scanner motor is used as an optical deflector. The polygon mirror scanner motor is a motor that rotates a polygon mirror (multi-faceted mirror) at high speed and scans the laser light irradiated from an LD (laser diode) onto a photoreceptor.

[0004] In Patent Document 1 described below, a polygon mirror rotation driving device is disclosed in which the lower surface of a polygon mirror 30 is disposed on a mirror mounting surface 26 of a rotor 20. The upper surface of the polygon mirror 30 is fixed by a spring portion 505 of a mirror pressing member 50 that is fitted into an engaging groove of the rotor 20.

[0005] Patent Document 2 described below discloses the same configuration as that of Patent Document 1.

[0006] Patent Document 3 described below discloses a polygon mirror scanner motor in which the lower surface of a polygon mirror 5 is disposed on a support surface 2c of a boss 2. As shown therein, a protruding portion at the upper portion of the polygon mirror 5 is fixed by a mirror pressing spring 110 that is fitted into a groove 101b of a shaft 101. Figure 8 As shown, a protruding portion at the upper portion of the polygon mirror 5 is fixed by a mirror pressing spring 110 that is fitted into a groove 101b of a shaft 101.

[0007] Patent Document 4 described below discloses a configuration similar to that of Patent Document 3.

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-241741

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2000-241742

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 2006-187970

[0011] Patent Document 4: Japanese Patent Application Laid-Open No. 2010-39337

[0012] Figure 13 is a partially enlarged view for explaining the configuration for holding the polygon mirror P in the first example of the prior art.

[0013] Refer to Figure 13 , on a sleeve 509 mounted on a motor rotating shaft, a support surface 507 is formed. The polygon mirror P is placed on the support surface 507. The inner diameter of the polygon mirror P is in contact with the rotating shaft of the sleeve 509.

[0014] On the upper surface of the polygon mirror P, a mirror fixing spring 505 is provided. Above the mirror fixing spring 505, a spring fixing ring 501 for fixing the mirror fixing spring 505 is provided. The spring fixing ring 501 embeds its inner diameter into the rotating shaft of the sleeve 509.

[0015] The mirror fixing spring 505 presses the polygon mirror P at a position above the support surface 507 with respect to the support surface 507. Thus, the polygon mirror P is clamped and fixed by the mirror fixing spring 505 and the support surface 507.

[0016] In Figure 13 the configuration, the spring fixing ring 501 for fixing the mirror fixing spring 505 is necessary. On the other hand, in order to reduce the cost of the polygon mirror scanner motor, it is desired to reduce the number of components.

[0017] In addition, when the pressing position (load position) of the mirror fixing spring 505 is set inside, the spring load becomes large, causing deformation of the polygon mirror P, so it is difficult to reduce the diameter of the pressing position. Furthermore, since the tip of the mirror fixing spring 505 is in a straight shape, it is difficult for the mirror fixing spring 505 to slide on the top surface of the polygon mirror P during spring pressing. Therefore, there is a problem that the mirror fixing spring 505 bites into the polygon mirror P and easily deforms the polygon mirror P.

[0018] Figure 14 It is a partial enlarged view for explaining the configuration of holding the polygon mirror P in the second example of the prior art.

[0019] As a configuration for seeking to reduce the number of components, it is possible to consider Figure 14 the configuration.

[0020] In Figure 14 the configuration, the mirror fixing spring 605 is fixed by forming a spring fixing groove 601 on the sleeve 609. Thus, it is possible to eliminate the Figure 13 spring fixing ring 501.

[0021] In Figure 13 , Figure 14 any one of them, the pressing positions of the mirror fixing springs 505 and 605 and the positions of the support surfaces 507 and 607 are substantially equal in the radial direction (the distances from the rotating shaft are substantially equal, and on the planes of the support surfaces 507 and 607 that contact the polygon mirror P, there are the pressing positions of the mirror fixing springs 505 and 605). Summary of the Invention

[0022] An object of the present invention is to provide a polygon mirror scanner motor capable of accurately mounting a polygon mirror.

[0023] To achieve the above object, according to a technical solution of the present invention, a polygon mirror scanner motor includes: a sleeve on which a polygon mirror is mounted and which can rotate about a rotation axis; a support surface that can rotate about the rotation axis together with the sleeve; and a mirror fixing spring for fixing the polygon mirror; the polygon mirror has a first surface and a second surface; the first surface of the polygon mirror contacts the support surface; the second surface of the polygon mirror is pressed by the mirror fixing spring; the distance between the rotation axis and the pressing position where the mirror fixing spring presses the polygon mirror is shorter than the distance between the rotation axis and the position where the polygon mirror contacts the support surface; when the difference between the outer radius and the inner radius of the polygon mirror is set as A, and the difference between the distance between the rotation axis and the pressing position where the mirror fixing spring presses the polygon mirror and the distance between the rotation axis and the position where the polygon mirror contacts the support surface is set as C;

[0024] 0 < C ≤ A / 4

[0025] the relationship holds; the inner diameter of the polygon mirror contacts the sleeve; when the distance in the direction orthogonal to the rotation axis between the position where the inner diameter of the polygon mirror contacts the sleeve and the position of the support surface is set as E,

[0026] A / 3 ≤ E ≤ A / 2

[0027] the relationship holds.

[0028] Preferably: the mirror fixing spring presses the flat portion of the polygon mirror.

[0029] Preferably: the length of the support surface in the direction orthogonal to the rotation axis is longer than 0.1 mm.

[0030] Preferably: on the sleeve, a spring fixing groove is formed; the mirror fixing spring is engaged with the spring fixing groove; when the plate thickness of the mirror fixing spring is set as t and the depth of the spring fixing groove in the direction orthogonal to the rotation axis is set as W,

[0031] t < W

[0032] the relationship holds.

[0033] Preferably: the mirror fixing spring has a curved surface portion; the mirror fixing spring presses the flat portion of the polygon mirror through the curved surface portion; the radius of curvature R of the curved surface portion is larger than 0.2 mm.

[0034] Preferably, the mirror fixing spring has a curved surface portion; the mirror fixing spring presses the flat surface portion of the polygon mirror through the curved surface portion; a flat surface portion is provided outside the curved surface portion of the mirror fixing spring; the angle θ1 between the flat surface portion provided on the mirror fixing spring and the flat surface portion of the polygon mirror is greater than 2°.

[0035] Preferably, a spring fixing groove is formed on the sleeve; the mirror fixing spring is engaged with the spring fixing groove by the flat surface of its inner end; the angle θ2 between the flat surface of the inner end of the mirror fixing spring and the plane parallel to the rotation axis is less than 45°.

[0036] According to another technical solution of the present invention, a polygon mirror scanner motor includes: a sleeve on which a polygon mirror is mounted and which can rotate about a rotation axis; a support surface that can rotate about the rotation axis together with the sleeve; and a mirror fixing spring that fixes the polygon mirror; the polygon mirror has a first surface and a second surface; the first surface of the polygon mirror contacts the support surface; the second surface of the polygon mirror is pressed by the mirror fixing spring; the distance between the rotation axis and the pressing position where the mirror fixing spring presses the polygon mirror is shorter than the distance between the rotation axis and the position where the polygon mirror contacts the support surface; the mirror fixing spring presses the flat surface portion of the polygon mirror.

[0037] Preferably, the mirror fixing spring has a curved surface portion; the mirror fixing spring presses the flat surface portion of the polygon mirror through the curved surface portion.

[0038] According to the present invention, a polygon mirror scanner motor capable of accurately mounting a polygon mirror can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a perspective view of a polygon mirror scanner motor in an embodiment of the present invention.

[0040] Figure 2 is Figure 1 a side view of the sleeve 105 of the polygon mirror scanner motor.

[0041] Figure 3 is a perspective view of a part of the sleeve 105 of the polygon mirror scanner motor observed obliquely from above. Figure 1 of the polygon mirror scanner motor.

[0042] Figure 4 is a perspective view of a part of the sleeve 105 of the polygon mirror scanner motor observed obliquely from below. Figure 1 of the polygon mirror scanner motor.

[0043] Figure 5 is used to Figure 1A three-dimensional sectional view showing the structure of the sleeve 105 of the polygon mirror scanner motor.

[0044] Figure 6 is Figure 1 A perspective view and a side view of the mirror fixing spring 101 of the polygon mirror scanner motor.

[0045] Figure 7 is Figure 1 A top view of the mirror fixing spring 101 of the polygon mirror scanner motor.

[0046] Figure 8 is for Figure 1 A partial sectional view showing the fixing state of the polygon mirror P in the polygon mirror scanner motor.

[0047] Figure 9 is for Figure 1 A partial sectional view showing the function brought by the mirror fixing spring 101 in the polygon mirror scanner motor.

[0048] Figure 10 is for Figure 1 A partial sectional view showing the function brought by the mirror fixing spring 101 in the polygon mirror scanner motor.

[0049] Figure 11 is for Figure 8 A diagram showing the dimension of C.

[0050] Figure 12 A diagram showing the effects in the embodiments of the present invention.

[0051] Figure 13 A partially enlarged view showing the structure for holding the polygon mirror P in the first example of the prior art.

[0052] Figure 14 A partially enlarged view showing the structure for holding the polygon mirror P in the second example of the prior art.

[0053] Explanation of reference numerals

[0054] 101, mirror fixing spring

[0055] 105, sleeve

[0056] 121, spring fixing groove

[0057] 123, supporting surface

[0058] 125, frustum portion

[0059] 127, cylindrical portion

[0060] 129, cylindrical portion

[0061] 301. Pressing section

[0062] 305. Engaging section

[0063] A. Difference between the outer radius and the inner radius of the polygon mirror P

[0064] B. Horizontal distance (distance in the direction orthogonal to the rotation axis) between the pressing position where the mirror fixing spring 101 presses the polygon mirror P and the outer diameter position of the polygon mirror P

[0065] C. Difference between the distance from the central position of the inner diameter and the outer diameter of the support surface 123 to the motor rotation axis (distance between the motor rotation axis and the position where the polygon mirror P contacts the support surface 123) and the distance between the motor rotation axis and the pressing position where the mirror fixing spring 101 presses the polygon mirror P

[0066] D. Horizontal distance between the pressing position where the mirror fixing spring 101 presses the polygon mirror P and the inner diameter portion of the polygon mirror P (contact portion between the inner diameter portion of the polygon mirror P and the sleeve 105)

[0067] E. Horizontal distance between the central position of the inner diameter and the outer diameter of the support surface 123 and the inner diameter portion of the polygon mirror P (contact portion between the inner diameter portion of the polygon mirror P and the sleeve 105)

[0068] W. Depth of the spring fixing groove 121 in the direction orthogonal to the motor rotation axis

[0069] t. Plate thickness of the mirror fixing spring 101

[0070] ΦDa. Diameter of the circle centered on the motor rotation axis and passing through the inner diameter side end of the support surface 123

[0071] ΦDb. Diameter of the circle centered on the motor rotation axis and passing through the outer diameter side end of the support surface 123

[0072] ΦDp. Diameter of the circle centered on the motor rotation axis and passing through the multiple pressing positions where the mirror fixing spring 101 presses the polygon mirror P

[0073] MT. Motor

[0074] P. Polygon mirror Detailed implementation mode

[0075] Figure 1 is a perspective view of a polygon mirror (polygon mirror, polygon mirror) scanner motor in an embodiment of the present invention

[0076] As shown in the figure, the polygon mirror scanner motor includes: a base portion B formed with a control circuit, a motor MT, a sleeve 105 mounted on the rotating shaft of the motor MT, a polygon mirror P placed on the supporting surface of the sleeve 105, and a mirror fixing spring 101 that presses the polygon mirror P onto the supporting surface from above.

[0077] Figure 2 is Figure 1 a side view of the sleeve 105 of the polygon mirror scanner motor. Figure 3 is a perspective view of a part of the sleeve 105 of the polygon mirror scanner motor as viewed obliquely from above Figure 1 thereof. Figure 4 is a perspective view of a part of the sleeve 105 of the polygon mirror scanner motor as viewed obliquely from below Figure 1 thereof. Figure 5 is a perspective sectional view for explaining the structure of the sleeve 105 of the polygon mirror scanner motor for Figure 1 thereof.

[0078] Referring to Figures 2 - 5 , the sleeve 105 has a cylindrical shape with its longitudinal direction as the rotating shaft. At the lower part of the sleeve 105, there is a disc portion that rotates around the rotating shaft of the motor MT. Above this disc portion, a ring-shaped supporting surface 123 is formed. Above the part of the sleeve 105 where the disc portion is formed, in order from below, it includes: a cylindrical portion 127, a frustum of a cone portion 125 located above the cylindrical portion 127 and having a smaller diameter as it goes up, a cylindrical portion 129 located above the frustum of a cone portion 125, and a spring fixing groove 121 formed by providing a cylindrical portion with a larger diameter than the cylindrical portion 129 at the upper part of the cylindrical portion 129. The above-mentioned disc, supporting surface 123, cylindrical portion 127, frustum of a cone portion 125, cylindrical portion 129, and spring fixing groove 121 are circular when viewed from the extending direction of the rotating shaft of the motor MT, and these circles are concentric. The above-mentioned disc, supporting surface 123, cylindrical portion 127, frustum of a cone portion 125, cylindrical portion 129, and spring fixing groove 121 can be integrally formed, or a part or all of them can be formed separately and then bonded.

[0079] Figure 6 is Figure 1 a perspective view and a side view of the mirror fixing spring 101 of the polygon mirror scanner motor. Figure 6 For (A), it is a perspective view, and for (B), it is a side view. Figure 7 is Figure 1 a top view of the mirror fixing spring 101 of the polygon mirror scanner motor.

[0080] As Figure 7 shown, the mirror fixing spring 101 has a pressing portion 301 that crosses the ring-shaped outer diameter when viewed from above ( Figure 7a shape protruding in four directions of up, down, left, and right). Thus, the mirror fixing spring 101 can press the polygon mirror P at four positions. As Figure 1 shown, as an example, an example is shown where the pressing positions are arranged on the lines where the perpendiculars to the respective multiple reflecting surfaces (four in this embodiment) of the polygon mirror P intersect the center of the rotation axis. However, the pressing positions are not limited to such positions.

[0081] On the inner diameter of the annular portion of the mirror fixing spring 101, engaging portions 305 are provided in four directions of upper right, lower right, upper left, and lower left of Figure 7 . The engaging portion 305 is a portion that engages with the spring fixing groove 121 of the sleeve 105 and is used to fix the mirror fixing spring 101 to the sleeve 105. The portion of the inner diameter of the annular portion where the engaging portion 305 is not provided ( Figure 7 the four-directional portions of up, down, left, and right) becomes cutout portions extending in the four directions of up, down, left, and right of Figure 7 . The cutout portions extend to the vicinity of the pressing portion 301. With such a shape, the mirror fixing spring 101 functions as a spring for pressing the polygon mirror P.

[0082] As Figure 6 shown, near the pressing portion 301, the end of the mirror fixing spring 101 is bent upward, and the pressing portion 301 is formed of a curved surface. The polygon mirror P is pressed by this curved surface portion. Since the polygon mirror P is not pressed by the straight-shaped portion, it is possible to prevent the mirror fixing spring 101 from being caught in the polygon mirror P. On the top side (outer side) closer to the top than this curved surface, the mirror fixing spring 101 is provided as a plane.

[0083] When assembling the polygon mirror scanner motor, the inner diameter of the polygon mirror P is nested on the cylindrical portion 127 of the sleeve 105 from above, and the lower surface of the polygon mirror P is brought into contact with the annular support surface 123. Then, while fitting the inner diameter of the mirror fixing spring 101 to the outer diameter of the sleeve 105, the mirror fixing spring 101 is nested from above the sleeve 105 and moved downward until the top of the engaging portion 305 is inserted into the spring fixing groove 121 of the sleeve 105. When the top of the engaging portion 305 is inserted into the spring fixing groove 121 of the sleeve 105, the pressing portion 301 presses the polygon mirror P against the support surface 123 with an appropriate spring force.

[0084] Here, the surface of the polygon mirror P that contacts the support surface 123 ( Figure 8 the lower surface in Figure 8 ) is referred to as the first surface, and the surface of the polygon mirror P that is pressed by the mirror fixing spring 101 ( Figure 8 the upper surface in

[0085] Figure 8 is used for Figure 1Partial cross-sectional view illustrating the fixed state of polygon mirror P in the polygon mirror scanner motor.

[0086] Figure 8 It shows a part of a cross-section (central cross-section of the polygon mirror scanner motor) that includes the motor rotation axis of the polygon mirror scanner motor and is orthogonal to the reflecting surface of polygon mirror P. Figure 8 It shows a cross-section viewed from a direction orthogonal to the motor rotation axis, showing the part on the right side of the motor rotation axis.

[0087] In the figure, the inner diameter of polygon mirror P is nested on the outer diameter of sleeve 105, and the lower surface (first surface) of polygon mirror P contacts above the support surface 123. The engaging portion 305 of mirror fixing spring 101 engages with the spring fixing groove 121 of sleeve 105. The pressing portion 301 of mirror fixing spring 101 presses downward (applies pressure) on the flat portion (the part without protrusions, etc.) of the upper surface (second surface) of polygon mirror P.

[0088] In Figure 8 it, the diameter of the circle passing through multiple pressing positions (in this embodiment, four positions) where mirror fixing spring 101 presses on polygon mirror P with the motor rotation axis as the center is represented by ΦDp. The diameter of the circle passing through the inner diameter side end of support surface 123 with the motor rotation axis as the center is represented by ΦDa. The diameter of the circle passing through the outer diameter side end of support surface 123 with the motor rotation axis as the center is represented by ΦDb.

[0089] Here, the polygon mirror scanner motor is designed such that

[0090] ΦDp < ΦDa < ΦDb

[0091] ΦDb - ΦDa > 0.1 mm

[0092] the relationship holds.

[0093] That is, the distance between the motor rotation axis and the pressing positions where mirror fixing spring 101 presses on polygon mirror P is shorter than the distance between the motor rotation axis and the positions where polygon mirror P contacts support surface 123. In addition, the length of support surface 123 in the direction orthogonal to the motor rotation axis is longer than 0.1 mm.

[0094] Furthermore, in Figure 8 it, the difference between the outer radius and the inner radius of polygon mirror P is represented by A. Here, the so-called outer radius refers to the distance from the rotation axis of polygon mirror P to the outer circumference (reflecting surface) of polygon mirror P. The so-called inner radius refers to the distance from the rotation axis of polygon mirror P to the outer circumference of the hole portion formed in the central portion of polygon mirror P through which sleeve 105 is inserted.

[0095] The horizontal distance (distance in the direction orthogonal to the rotation axis) between the pressing position where the mirror fixing spring 101 presses on the polygon mirror P and the outer diameter position of the polygon mirror P is represented by B. Here, the outer diameter position of the polygon mirror P refers to the position of the outer periphery (reflective surface) of the polygon mirror P closest to the rotation axis of the polygon mirror P.

[0096] The difference between the distance from the rotation axis of the motor to the central position of the inner diameter and the outer diameter of the support surface 123 (the distance between the rotation axis of the motor and the position where the polygon mirror P contacts the support surface 123) and the distance between the rotation axis of the motor and the pressing position where the mirror fixing spring 101 presses on the polygon mirror P is represented by C.

[0097] The horizontal distance (distance in the direction orthogonal to the rotation axis) between the pressing position where the mirror fixing spring 101 presses on the polygon mirror P and the inner diameter portion of the polygon mirror P (the contact portion between the inner diameter portion of the polygon mirror P and the sleeve 105) is represented by D.

[0098] The horizontal distance (distance in the direction orthogonal to the rotation axis) between the central position of the inner diameter and the outer diameter of the support surface 123 and the inner diameter portion of the polygon mirror P (the contact portion between the inner diameter portion of the polygon mirror P and the sleeve 105) is represented by E.

[0099] The height position of the uppermost part (the tip of the engaging portion 305) of the spring fixing groove 121 with the upper surface of the polygon mirror P as the reference surface is represented by h.

[0100] The depth of the spring fixing groove 121 in the direction orthogonal to the rotation axis of the motor is represented by W.

[0101] The plate thickness of the mirror fixing spring 101 is represented by t.

[0102] The polygon mirror scanner motor in this embodiment is designed such that

[0103] 0 < C ≤ A / 4

[0104] A / 3 ≤ E ≤ A / 2

[0105] t < W

[0106] the relationship holds.

[0107] Regarding the dimension of C, it means that the pressing position where the mirror fixing spring 101 presses in the radial direction (the direction outward from the rotation axis) of the polygon mirror P is located at a position closer to the inner side in the radial direction than the position of the support surface 123 in the radial direction.

[0108] Regarding the dimension of E, it is stated that the position of the support surface 123 is more than 1 / 3 of A, which is the difference between the outer radius and the inner radius of the polygon mirror P, away from the inner radius of the polygon mirror P toward the reflection surface side (outside the rotation axis) of the polygon mirror P. The closer the position of the support surface 123 is to the reflection surface of the polygon mirror P, the greater the deformation becomes. Therefore, the upper limit value of the value of E is set to half of A.

[0109] Regarding the dimension of t, in order to prevent the mirror fixing spring 101 inserted into the spring fixing groove 121 from falling off, the depth W of the spring fixing groove 121 is set to be equal to or greater than the spring thickness t. In addition, the pressing position for pressing the mirror fixing spring 101 is set to the inner side, and in order to adjust the pressing load, the plate thickness t is reduced.

[0110] In addition, if A is 5 mm, then

[0111] 0 < C ≤ 1.25,

[0112] 1.67 ≤ E ≤ 2.5;

[0113] If A is 5.07 mm, then

[0114] 0 < C ≤ 1.27,

[0115] 1.69 ≤ E ≤ 2.535.

[0116] Figure 9 is a partial cross-sectional view for explaining the action brought by the mirror fixing spring 101 in the Figure 1 polygon mirror scanner motor.

[0117] The tip in the outer diameter direction of the mirror fixing spring 101 becomes the pressing portion 301. The pressing portion 301 has a curved surface portion. The mirror fixing spring 101 presses the flat surface portion of the polygon mirror P through this curved surface portion. The radius of curvature of the curved surface portion is represented by R. Here, the polygon mirror scanner motor is designed such that

[0118] R > 0.2 mm

[0119] the relationship holds. The horizontal surface of the mirror is pressed by the rounded surface portion of the mirror fixing spring 101.

[0120] In addition, a flat surface portion is provided on the mirror fixing spring 101 outside the curved surface portion of the pressing portion 301. The angle between the flat surface portion provided on the mirror fixing spring 101 and the flat surface portion of the polygon mirror P is represented by θ1.

[0121] In addition, the angle between the flat surface of the inner end portion of the mirror fixing spring 101 and the surface parallel to the rotation axis (the outer peripheral surface of the cylindrical portion 129) is represented by θ2. Here, the polygon mirror scanner motor is designed such that

[0122] θ1 > 2°,

[0123] θ2 < 45°

[0124] The relationship holds.

[0125] By adjusting θ2 and adjusting the inner diameter of the mirror fixing spring 101 and the outer diameter of the spring fixing groove 121, as shown by the arrows "D1" and "D2" in Figure 9 a top thrust force acting substantially in the vertical direction is designed to act on the sleeve 105 and the polygon mirror P.

[0126] Figure 10 is a partial cross-sectional view for explaining the action of the mirror fixing spring 101 in the polygon mirror scanner motor for Figure 1 the polygon mirror.

[0127] By setting θ2 < 45°, it is possible to suppress the deformation of the mirror fixing spring 101 in the direction of the inner diameter of the sleeve 105 when installing the mirror fixing spring 101. By making θ2 smaller than 45°, when the polygon mirror P is fixed by the mirror fixing spring 101, the mirror fixing spring 101 deforms in the direction of the inner diameter of the sleeve 105, and at the same time, the mirror fixing spring 101 pushes against the spring fixing groove 121, and more force is applied in the direction of the arrow "D4" in Figure 10 . When θ2 is set to 45° or more, the force is likely to be applied in the direction of the arrow "D3" in Figure 10 , so it is preferably set that θ2 < 45°.

[0128] Figure 11 is a diagram for explaining the dimension C of Figure 8 .

[0129] In Figure 11 , the relationship between the position of the support surface 123 and the pressurizing positions G1 and G2 where the mirror fixing spring 101 pressurizes the polygon mirror P is shown. In addition, the inclination of the reflecting surface of the polygon mirror P is indicated by P1 to P3. The more from P1 to P3, the more the reflecting surface of the polygon mirror P is inclined from the rotation axis of the motor.

[0130] Assuming that the polygon mirror P is pressed with the same load and the same amount of deflection is generated, the larger the dimension C, the more adverse the influence on the reflecting surface of the polygon mirror P becomes. Therefore, the polygon mirror scanner motor is designed such that the relationship 0 < C ≤ A / 4 holds.

[0131] Figure 12 is a diagram for explaining the effects in the embodiments of the present invention.

[0132] In the figure, the relationship between the mirror surface inclination (skew) and the mirror surface eccentricity of the polygon mirror of the polygon mirror scanner motor before (conventional example) and after (embodiment) applying the present invention is shown.

[0133] It can be seen that by implementing the present invention, the pressing position of the mirror fixing spring on the polygon mirror changes to the inner side of the support surface, whereby the deformation of the polygon mirror is reduced and the mirror surface tilt is reduced.

[0134] As described above, after changing the relationship between the pressing position in the radial direction of the polygon mirror and the support surface position, the present inventor has found a positional relationship having a tendency to reduce the deformation of the polygon mirror and reduce its mirror surface tilt.

[0135] Furthermore, when fixing the mirror fixing spring, in order to suppress the deformation of the mirror fixing spring in the direction of the inner diameter of the sleeve, the angle of θ2 is restricted. Furthermore, in order to prevent an excessive load from being applied to the polygon mirror when the mirror fixing spring is inserted, the dimensions of R and θ1 are restricted.

[0136] In the polygon mirror scanner motor described in the above embodiment, it is possible to reduce the number of components. In addition, the deformation of the polygon mirror is reduced and the mirror surface tilt is reduced (it is possible to improve the mirror surface tilt strength and the polygon mirror can be installed with high precision).

[0137] The above embodiment should be regarded as illustrative in all aspects rather than restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include the semantics equivalent to the claims and all changes within the scope.

Claims

1. A mirror fixing spring for a polygon mirror scanner motor, which presses the second surface of a polygon mirror having a first surface and a second surface on the opposite side of the first surface against the supporting surface of a sleeve in the longitudinal direction of a rotating shaft, the supporting surface being in contact with the first surface of the polygon mirror, the mirror fixing spring comprising: a pressing portion having a curved surface portion formed by a curved surface; an annular portion located inside the pressing portion, the inner peripheral portion of the annular portion having a plurality of engaging portions and a plurality of notch portions located between the plurality of engaging portions in the circumferential direction, in the radial direction, the tips of the plurality of notch portions are located inside the curved surface portion of the pressing portion, in the radial direction, the plurality of notch portions located above the second surface of the polygon mirror penetrate the annular portion from the inner peripheral portion of the annular portion and extend to the vicinity of the curved surface portion of the pressing portion.

2. An assembling method for a polygon mirror scanner motor, wherein, the motor comprises: a rotating shaft; a sleeve mounted on the rotating shaft; a polygon mirror; the mirror fixing spring of the polygon mirror scanner motor according to claim 1 for fixing the polygon mirror, the assembling method comprising: a first step of nesting the inner peripheral portion of the polygon mirror on a first cylindrical portion of the sleeve; a second step of nesting the mirror fixing spring on the sleeve.

3. The assembling method for a polygon mirror scanner motor according to claim 2, wherein, the sleeve includes the supporting surface, the first step includes a step of bringing the surface of the polygon mirror into contact with the supporting surface.

4. The assembling method for a polygon mirror scanner motor according to claim 2, wherein, it includes a third step of pressing the polygon mirror against the supporting surface by the pressing portion of the mirror fixing spring.

5. A polygon mirror scanner motor, which comprises: a sleeve having a supporting surface and an outer peripheral surface; a polygon mirror having a first surface in contact with the supporting surface and a second surface on the opposite side of the first surface; a mirror fixing spring that presses the second surface of the polygon mirror against the supporting surface in the longitudinal direction of a rotating shaft, the polygon mirror having an inner peripheral surface in contact with the outer peripheral surface of the sleeve, the mirror fixing spring comprising: a pressing portion having a curved surface portion formed by a curved surface and an annular portion located inside the pressing portion, the inner peripheral portion of the annular portion having a plurality of engaging portions and a plurality of notch portions located between the plurality of engaging portions in the circumferential direction, in the radial direction, the tips of the plurality of notch portions are located inside the curved surface portion of the pressing portion, in the radial direction, the plurality of notch portions penetrate the annular portion from the inner peripheral portion of the annular portion and extend to the vicinity of the curved surface portion of the pressing portion, in the longitudinal direction of the rotating shaft, the plurality of notch portions are located above the second surface of the polygon mirror, in the longitudinal direction of the rotating shaft, the curved surface portion of the pressing portion presses the second surface of the polygon mirror against the supporting surface in contact with the first surface.

6. The polygon mirror scanner motor according to claim 5, wherein, the annular portion has the inner peripheral portion and the outer peripheral portion, the plurality of notch portions are located between the inner peripheral portion and the outer peripheral portion.

7. The multi-faceted mirror scanner motor according to claim 5, comprising: a base portion formed with a control circuit, and a motor.

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