JPH0798437A - Light beam scanning device - Google Patents

Abstract

PURPOSE:To keep the deformation amount of a deflection surface small and surface accuracy excellent by essentially composing a rotary deflecting device of a resin material and making thickness in the vicinity of the deflection surface larger than that in the vicinity of the center of rotation. CONSTITUTION:A motor 5 is constituted of a stator fixed on a substrate 1, a rotor 7 which can rotate around the stator, and a rotary shaft 8 rotatably provided at the axial center part of the stator. A pedestal 10 is coupled with the rotor 7 and the rotary shaft 8, and the three of them can integrally rotate. The rotary deflecting device 15 is integrally molded of the synthetic resin material such as polycarbonate or acrylic by injection molding, and is constituted as a regular square body provided with the deflection surfaces 16a to 16d on the outer peripheral surface. The deflection surfaces 16a to 16d are finished as mirror surfaces. Then, the device 15 is provided with a hole 17 in its center part and a depression formed in a central part, and it is constituted so that the thickness (a) of the peripheral part 18a in the vicinity of the deflection surface is larger than the thickness (c) of the central part 18b being the vicinity part of the center of rotation. The device 15 is fixed on the rotary shaft 8 by the center hole 17 through the pedestal 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam scanning device, and more particularly to a light beam scanning device for deflecting a light beam by rotating a rotary deflector at a constant speed and scanning the light receiving surface.

[0002]

2. Description of the Related Art Conventionally, as a light beam scanning device used in a laser printer or an image reader, a device provided with a rotary deflector is known. The rotary deflector is a regular polygonal body having a plurality of deflection surfaces on its outer peripheral surface, is attached to the rotation shaft of a motor, rotates with the rotation of the motor, and deflects a light beam emitted from a semiconductor laser or the like. The surface is deflected to a constant angular velocity.

Conventionally, the rotary deflector is made of metal such as aluminum or glass. However, in recent years, various attempts have been made to manufacture a resin material for the purpose of weight reduction and mass productivity. However, the rotary deflector made of a resin material has a problem that the deflecting surface is slightly deformed into a concave shape or a convex shape due to the centrifugal force generated by the rotation. When the deflecting surface is deformed into a concave shape or a convex shape, the surface accuracy is deteriorated, the image plane is deviated from the light receiving surface, and sufficient optical performance cannot be obtained.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotary deflector capable of maintaining a good surface accuracy with a small amount of deformation of a deflecting surface during rotation, and having sufficient optical performance. An object is to provide a light beam scanning device. In order to achieve the above object, the light beam scanning device according to the present invention includes a rotary deflector which is made of a resin material as a main component and has a regular polygonal shape having a plurality of deflection surfaces on its outer peripheral surface. The thickness was set to be larger than the thickness in the vicinity of the center of rotation, and this rotary deflector was attached to the rotary shaft of the motor integrally with the rotary shaft via the pedestal. By making the thickness in the vicinity of the deflection surface larger than the thickness in the vicinity of the center of rotation, the rigidity in the vicinity of the deflection surface becomes relatively large, and the amount of deformation of the deflection surface at the time of rotation becomes small. Will be maintained.

Further, in the light beam scanning device according to the present invention, the rotary deflector is set so that the thickness in the diagonal direction is smaller than the thickness in the deflecting surface direction. As a result, the rigidity in the vicinity of the deflecting surface becomes relatively large, the amount of deformation of the deflecting surface during rotation becomes small, and the required optical performance is maintained.

Further, in the light beam scanning device according to the present invention, the physical property values are made different in the vicinity of the deflecting surface of the rotary deflector whose main component is a resin material and in other portions. For example, different materials were used for the portion requiring rigidity and the other portions, and a material having a large Young's modulus was used for the portion requiring rigidity. This reduces the amount of deformation of the deflecting surface during rotation,
It will maintain the required optical performance.

Further, in the light beam scanning device according to the present invention, the rotary deflector is fixed by being sandwiched between the pedestal and the mounting member in the vertical direction, and the fixed portion is set to a portion where the deformation of the rotary deflector is large. The rigidity of the mounting member suppresses the deformation of each deflection surface during rotation.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a light beam scanning device according to the present invention will be described below with reference to the accompanying drawings. (First Embodiment, see FIGS. 1 to 12) In FIGS. 1 and 2, a light beam scanning device is roughly composed of a substrate 1 and a motor 5.
The pedestal 10, the rotary deflector 15, and the fixture 20.

The substrate 1 has a required rigidity, supports the motor 5, and is mounted with various electronic parts constituting a drive control circuit of the motor 5. The motor 5 is composed of a stator 6 fixed to the substrate 1, a rotor 7 rotatable around the stator 6, and a rotary shaft 8 rotatably provided at the axial center of the stator 6. The pedestal 10 is connected to the rotor 7 and the rotating shaft 8, and these three members can rotate integrally. The pedestal 10 is made of a metal material, and has a polished pedestal portion 11 in its central portion.

The rotary deflector 15 is integrally molded by injection molding from a synthetic resin material such as polycarbonate or acrylic, and has four deflection surfaces 16a to 16d on its outer peripheral surface.
Is formed, and the deflection surfaces 16a to 16d are mirror-finished. Further, the rotary deflector 15 has a hole 17 in the center and a recess is formed in the center, and the thickness a of the peripheral portion 18a near each deflecting surface is the thickness c of the center portion 18b near the center of rotation. Larger than that (see FIG. 3).

The rotary deflector 15 has a center hole 17 fitted on the upper portion of the rotary shaft 8 and is mounted on the pedestal 11 of the pedestal 10. Then, with the mounting tool 20 placed on the upper end surface of the rotary shaft 8, the screws 27 are screwed into the screw holes formed on the upper part of the rotary shaft 8 with further washers 25 and 26 interposed. Thus, the rotary deflector 15 is fixed to the rotary shaft 8. As shown in FIG. 4, the fixture 20 has an insertion hole 21 for the screw 27 in the center and wedge-shaped projections 22 on both sides. Due to the tightening force from the screw 27, the tip of the projecting piece 22 pierces the surface of the rotary deflector 15 and presses the rotary deflector 15. The rotary deflector 15 is integrally connected to the rotary shaft 8 on the pedestal 10 by the pressing force of the fixture 20.

Here, the peripheral portion 18a of the rotary deflector 15
The amount of deformation of the deflecting surfaces 16a to 16d during rotation with respect to the thickness a and width b and the thickness c of the central portion 18b will be described. In the following description, “r direction” means a radial direction from the center, “x direction” means a direction perpendicular to each deflecting surface, and “y direction” means a longitudinal direction of each deflecting surface. “Axial surface distance” means the distance from the center of rotation to each deflection surface, and is indicated by R in FIG. The “deformation amount” refers to the amount of movement in the x direction or the r direction at each point in the y direction of the deflection surface during rotation. "Surface accuracy" means the difference between the maximum value and the minimum value of the amount of deformation. The deformation amount and the surface accuracy do not have to be good over the entire length of the deflection surface in the y direction, and may be good in the effective deflection area used for image formation.

In the first embodiment, the width b and the thickness c
Was set to 8 types shown in Table 1 below, and the amount of deformation of the deflecting surface during rotation was determined. FIG. 5 and the following graphs showing the amount of deformation are results obtained by simulating various rotary deflectors having specific shapes and physical property values using the finite element method as a model. Then, in FIG. 5 and the following graphs, the horizontal axis represents the length in the y direction starting from the center of the deflection surface,
The vertical axis represents the amount of deformation in the x direction or the r direction.

[0014]

[Table 1]

The rotary deflectors modeled in Experimental Examples 1 to 8 have an axial distance of 15 mm and a central hole 17 having a diameter of 5 mm.
Is a regular tetragon and has a Young's modulus of 210 kgf / mm ² ,
Poisson's ratio is 0.35 and specific gravity is 1.2,
It was rotated at 6685.5 rpm. 5 is Experimental Example 1, FIG. 6 is Experimental Example 2, FIG. 7 is Experimental Example 3, FIG. 8 is Experimental Example 4, and FIG.
Is Experimental Example 5, FIG. 10 is Experimental Example 6, FIG. 11 is Experimental Example 7, and FIG.
1, 61, 71, 81, 91, 101, 111, 121
Indicate.

As is clear from these Experimental Examples 1 to 8, the thickness a of the peripheral portion 18a is changed to the thickness c of the central portion 18b.
The deflection surfaces 16a to 16a
d has a small amount of deformation during rotation and maintains a flat surface with good surface accuracy.

(Second Embodiment, see FIGS. 13 to 19) In the second embodiment, the rotary deflector 30 shown in FIG. 13 is used. Like the rotary deflector 15, the rotary deflector 30 is made of a synthetic resin material and has deflection surfaces 31a to 3a on its outer peripheral surface.
It has a regular square shape having 1d and has a central hole 32. Further, the rotary deflector 30 is formed with grooves 33a, 33a having a width d in a diagonal direction, and the thickness e of the grooves 33a, 33a is set to be smaller than the other portion 33b, that is, the thickness f in the vicinity of the deflecting surface. ing.

The rotary deflector 30 is mounted by fitting the center hole 32 into the rotary shaft 8 of the motor 5 shown in FIGS. 1 and 2, and pressing the vicinity of the center hole 32 with the above-mentioned mounting tool 20, Fixed. Here, the deformation amounts of the deflection surfaces 31a to 31d during rotation with respect to the groove width d and the thicknesses e and f of the rotary deflector 30 are shown as Experimental Examples 9 to 14. In the second example, the width d and the thickness e were set to the six types shown in Table 2 below, and the amount of deformation of the deflecting surface during rotation was determined.

[0019]

[Table 2]

In the rotary deflector modeled in Experimental Examples 9 to 14, the axial distance is 15 mm, and the diameter of the central hole 32 is 5 mm.
Is a regular tetragon and has a Young's modulus of 210 kgf / mm ² ,
Poisson's ratio is 0.35 and specific gravity is 1.2,
It was rotated at 6685.5 rpm. FIG. 14 shows Experimental Example 9,
15 is an experiment example 10, FIG. 16 is an experiment example 11, FIG. 17 is an experiment example 12, FIG. 18 is an experiment example 13, and FIG. 19 is an x direction deformation amount in the experiment example 14, respectively, curves 141, 151, 1
61, 171, 181, 191 are shown.

As is clear from these Experimental Examples 9 to 14, by setting the thickness e of the groove portion 33a smaller than the thickness f of the portion 33b near the deflecting surface, the deflecting surfaces 31a to 3a.
1d has a small amount of deformation during rotation and maintains a flat surface with good surface accuracy.

(Third Embodiment, FIGS. 20 to 23) In the third embodiment, the rotary deflector 35 shown in FIG. 20 is used. The rotary deflector 35 has deflection surfaces 36a to 36 on its outer peripheral surface.
It is a regular tetragon having d and has a central hole 37.
Further, the diagonal portion 38a and the deflecting surface vicinity portion 38b are made of different materials as described below.

This rotary deflector 35 is also attached by fitting the center hole 37 into the rotary shaft 8 of the motor 5 shown in FIGS. 1 and 2, and pressing and fixing the vicinity of the center hole 37 with the fixture 20. To be done. Here, the physical property values of the materials used for the diagonal line portion 38a and the deflection surface vicinity portion 38b are shown in Experimental Examples 15 and 1.
6, 17 will be described.

[0024]

[Table 3]

[0025]

[Table 4]

[0026]

[Table 5]

The rotary deflectors modeled in these Experimental Examples 15, 16 and 17 were regular tetragons having an axial distance of 15 mm and a thickness of 3.75 mm, and were rotated at 6685.5 rpm. In Experimental Example 15 shown in Table 3, the diagonal line portion 3
The Young's modulus of the resin material used for 8a is 900 kgf /
In the case of a large value of mm ² , the deformation amount in the x direction is shown in FIG.
As shown by the curve 211 of No. 2, it is small and the surface accuracy is good.

In Experimental Example 16 shown in Table 4, the diagonal line portion 3
This is a case where the specific gravity of the resin material used for 8a is reduced to 0.8, the x-direction deformation amount is small as shown by the curve 221 in FIG. 22, and the surface accuracy is good. Experimental Example 17 shown in Table 5 is a case where a material in which 50% by weight of glass frit is mixed in polycarbonate is used as the diagonal line portion 38a, and the x-direction deformation amount is small as shown by a curve 231 in FIG. The surface accuracy is good.

Incidentally, in each of Experimental Examples 15, 16 and 17, the material of the portion 38b near the deflecting surface is polycarbonate. Generally, in a rotary deflector made of resin material,
At the time of rotation, each deflecting surface tends to be deformed into a concave shape when the surface is 4 or less, and is convex when the surface is 6 or more. The amount of deformation at a certain point is determined by the centrifugal force and reaction force acting on that point. The Poisson's ratio of the material is also relevant. Therefore, to reduce the amount of deformation during rotation,
It is possible to reduce the centrifugal force (decrease the specific gravity), increase the reaction force (increase the Young's modulus), and control the Poisson's ratio of the material.

In Experimental Example 15, in consideration of the fact that the deflecting surface generally deforms into a concave shape if there are four surfaces, the amount of deformation is suppressed by increasing the reaction force (Young's modulus) of the diagonal line portion 38a. This can be applied to a rotary deflector having four surfaces or less. Similarly, in Experimental Example 16, the amount of deformation was suppressed by reducing the centrifugal force (specific gravity) of the diagonal line portion 38a. This can be applied to a rotary deflector having four surfaces or less. In Experimental Example 17 as well, the amount of deformation is suppressed by increasing the reaction force, and the centrifugal force is slightly increased, but the effect of increasing the reaction force is more pronounced.

On the other hand, if the number of rotary deflectors is six or more, the deflecting surface is generally deformed into a convex shape, so it is necessary to select the physical property values opposite to the above. That is, the reaction force (Young's modulus) of the portion 38b near the deflection surface is increased or the centrifugal force (specific gravity) is decreased.

(Fourth Embodiment, See FIGS. 24 to 26) In the fourth embodiment, the rotary deflector 40 shown in FIG. 24 is used. The rotary deflector 40 has deflection surfaces 41a ...
It is a regular tetragon having 41d and has a central hole 42. Further, the peripheral portion 43 including the deflection surfaces 41a to 41d
As described below, the materials of the a and the central portion 43b are made different.

This rotary deflector 40 is also attached by fitting the central hole 42 into the rotary shaft 8 of the motor 5 shown in FIGS. 1 and 2, and pressing and fixing the vicinity of the central hole 42 with the fitting 20. To be done. Here, the physical property values of the materials used for the peripheral portion 43a and the central portion 43b will be described as Experimental Examples 18 and 19.

[0034]

[Table 6]

[0035]

[Table 7]

The rotary deflectors modeled in these Experimental Examples 18 and 19 have an axial distance of 15 mm and a thickness of 3.75.
mm, the width g of the peripheral portion is 2 mm, and is a regular tetragon.
It was rotated at 85.5 rpm. Experimental Example 18 shown in Table 6
Shows the case where the Young's modulus of the resin material used for the peripheral portion 43a is increased to 600 kgf / mm ² , the x-direction deformation amount is small as shown by the curve 251 in FIG. 25, and the surface accuracy is good.

In Experimental Example 19 shown in Table 7, the peripheral portion 43
When a material in which 30% by weight of glass frit is mixed in polycarbonate is used as a, the deformation amount in the x direction is small as shown by the curve 261 in FIG. 26, and the surface accuracy is good. In the fourth embodiment, the flattening of the deflection surface during rotation is achieved by setting the reaction force (Young's modulus) of the peripheral portion 43a large.

(Fifth Embodiment, see FIGS. 27 to 29) In the fifth embodiment and the sixth to eleventh embodiments described below, the attachment and / or the second attachment provided on the pedestal is rotated. By engaging with the deflector, deformation of the deflecting surface during rotation is suppressed as much as possible. It should be noted that the four-sided or six-sided rotary deflectors 52 and 55 shown in these embodiments are shown.
Is a resin material homogeneously molded.

27 to 29, the rotary deflector 52
Is a regular quadrangle having four deflection surfaces 53a to 53d, and is pressed and held by a mounting tool 63 on a pedestal 62.
The pedestal 62 can rotate integrally with the rotor 7 and the rotary shaft 8 of the motor 5 shown in FIGS. The rotary deflector 52 is mounted on a pedestal 62 with a center hole (not shown) fitted to the rotary shaft 8, and is pressed by a mounting tool 63. Fixture 6
3 is made of a metal material and has projecting pieces 64 at four corners,
It is fixed to the upper part by screws 27. The tip of the protruding piece 64 of the fixture 63 is sharp like a needle and pierces the surface of the rotary deflector 52 at a point h _{1 in} FIG. Each h ₁ point is set on a diagonal line H connecting each corner of the rotary deflector 52 and the center of rotation.

It is known that the four-sided rotary deflector deforms each of the deflecting surfaces into a concave shape during rotation. This deformation is due to the large deformation (elongation) of the resin material on the diagonal due to centrifugal force during rotation. Therefore, by increasing the reaction force at this deformed portion, it is possible to suppress the deflection surface from becoming concave. In the fifth embodiment, the protrusion 64 of the attachment 63 is
A portion of the rotary deflector 52 that is largely deformed, that is, a point h ₁ on the diagonal line H is pierced and pressed to be held by the rotary deflector 52, thereby suppressing the deformation of the deflecting surfaces 53a to 53d during rotation and achieving good surface accuracy. And

Further, by sticking the protrusion 64 of the fixture 63 on the surface of the rotary deflector 52, it is possible to reliably prevent "slip" between the rotary deflector 52 and the motor 5 at the start of rotation. The fifth embodiment can also be applied to a three-sided rotary deflector. Further, the protrusion 64 may be provided in an integral multiple of the number of surfaces.

(Sixth Embodiment, see FIGS. 30 to 32) This sixth embodiment uses a regular hexagonal rotary deflector 55 having six deflecting surfaces 56a to 56f.
5 is pressed and held on the base 62 by a mounting tool 65. The fixtures 65 are projecting pieces 66 arranged at even intervals in six places.
The tip of the protrusion 66 pierces the surface of the rotary deflector 55 at point i _{1 in} FIG. Each i ₁ point is a straight line I connecting the center of each deflection surface 56a to 56f and the center of rotation.
Is set on.

It is known that in the case of a rotary deflector having six or more surfaces, each deflecting surface is deformed into a convex shape during rotation. This deformation is due to the large deformation (elongation) of the resin material on the straight line I due to the centrifugal force during rotation. Therefore, by increasing the reaction force of this deformed portion, it is possible to suppress the convex shape of the deflection surface. In the sixth embodiment, the protrusion 66 of the fixture 65 pierces and presses and holds a portion of the rotary deflector 55 that is largely deformed, that is, the point i ₁ on the straight line I. ~ 56
The deformation of f was suppressed and the surface accuracy was improved. In addition,
The sixth embodiment can also be applied to a rotary deflector having a regular polygon having six or more surfaces. Further, the protrusion 66 may be provided in an integral multiple of the number of surfaces.

(Seventh embodiment, see FIGS. 33 to 35) This seventh embodiment is based on the same method as the fifth embodiment as a deformation suppressing measure, and is a four-sided regular polygonal rotary deflector 52. Is pressed and held on the pedestal 62 by the fixture 67. The fixture 67 has protrusions 68 at the four corners, and the protrusions 68 engage with the corners of the rotary deflector 52. That is, the fixture 6
7 restricts the rotary deflector 52 at a point h ₂ on the diagonal line H by the projecting piece 68, thereby suppressing the deflection shapes of the deflection surfaces 53a to 53d from becoming concave and preventing the surface accuracy from deteriorating.

(Eighth Embodiment, see FIGS. 36 to 38) This eighth embodiment uses the same method as the sixth embodiment as a deformation suppressing measure, and is a six-sided regular hexagonal rotary deflector 55. Is pressed and held on the pedestal 62 by the fixture 72. The fixture 72 has projecting pieces 73 at six corners, and the projecting pieces 73 engage with the central upper edge portions of the deflection surfaces 56a to 56f. That is, the fixture 72 restricts the rotary deflector 55 at the point i ₂ on the straight line I by the projecting piece 73, so that each deflection surface 56
The convex shape of a to 56f is suppressed, and the reduction of the surface accuracy is prevented.

(Ninth embodiment, see FIGS. 39 to 41) This ninth embodiment uses the same method as the fifth embodiment as a deformation suppressing measure, and is a four-sided regular polygonal rotary deflector 52. Of the second mounting tool 74, the front and back surfaces of which are provided on the base 62.
5 and the projecting piece 64 of the attachment 63 sandwich and hold.
The projecting pieces 75 and 64 pierce the point h ₁ on the diagonal line H from the front and back to hold the rotary deflector 52. As a result, it is possible to prevent the deflection surfaces 53a to 53d from being formed into a concave shape during rotation, and prevent the surface accuracy from decreasing.

(Tenth embodiment, see FIGS. 42 to 44) This tenth embodiment uses the same technique as the sixth embodiment as a deformation suppressing measure, and is a six-sided regular hexagonal rotary deflector 55.
The front and back surfaces of the above are sandwiched and held by the projecting piece 77 of the second mounting tool 76 and the projecting piece 66 of the mounting tool 65 provided on the pedestal 62. The protrusions 77 and 66 pierce the point i ₁ on the straight line I from the front and back to hold the rotary deflector 55. This prevents the deflection surfaces 56a to 56f from having a convex shape during rotation, and prevents reduction in surface accuracy.

(Eleventh embodiment, see FIGS. 45 to 47) This eleventh embodiment uses the same method as the fifth embodiment as a deformation suppressing measure, and is a rotation deflector 52 of a four-sided regular tetragon.
Is clamped and held by the second fixture 82 provided on the pedestal 62 and the fixture 67, and the corners of the rotary deflector 52 are engaged with the protrusions 83, 68 of the fixtures 82, 67. That is, the fixtures 82 and 67 restrict the rotary deflector 52 at the point h ₂ on the diagonal line H by the protrusions 83 and 68, thereby suppressing the deflection shapes of the deflecting surfaces 53a to 53d from becoming concave, and improving the surface accuracy. Prevent decline.

(Other Embodiments) The light beam scanning device according to the present invention is not limited to the above-mentioned various embodiments, but can be variously modified within the scope of the invention. In particular,
The eleventh embodiment shown in FIGS. 45 to 47 in which the rotary deflector is sandwiched from above and below can also be applied to a regular hexagonal rotary deflector.
In this case, as shown in FIGS.
3 and an engaging piece (not shown) provided on the pedestal 62 regulate the central upper and lower edges of each deflection surface.

Further, it is conceivable that the front and back portions of the rotary deflector are provided with asymmetrical shapes or physical properties to reduce the deformation of the deflecting surface during rotation. For example, in a four-sided rotary deflector, a certain amount of the lower side of each corner portion is cut off to give a geometric asymmetry. Alternatively, as a measure for providing physical asymmetry, the Young's modulus, specific gravity and / or Poisson's ratio may be partially different on the front and back surfaces of the rotary deflector.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a light beam scanning device according to a first embodiment.

FIG. 2 is a sectional view of the light beam scanning device according to the first embodiment.

FIG. 3 is a perspective view of a rotary deflector used in the first embodiment.

FIG. 4 shows the fixture used in the first embodiment,
(A) is a plan view and (B) is a front view.

FIG. 5 is a graph showing the amount of deformation in Experimental Example 1.

FIG. 6 is a graph showing the amount of deformation in Experimental Example 2.

FIG. 7 is a graph showing the amount of deformation in Experimental Example 3.

FIG. 8 is a graph showing the amount of deformation in Experimental Example 4.

FIG. 9 is a graph showing the amount of deformation in Experimental Example 5.

FIG. 10 is a graph showing the amount of deformation in Experimental Example 6.

FIG. 11 is a graph showing the amount of deformation in Experimental Example 7.

FIG. 12 is a graph showing the amount of deformation in Experimental Example 8.

FIG. 13 is a perspective view of a rotary deflector used in the second embodiment.

FIG. 14 is a graph showing the amount of deformation in Experimental Example 9.

FIG. 15 is a graph showing the amount of deformation in Experimental Example 10.

16 is a graph showing the amount of deformation in Experimental Example 11. FIG.

FIG. 17 is a graph showing the amount of deformation in Experimental Example 12.

FIG. 18 is a graph showing the amount of deformation in Experimental Example 13.

FIG. 19 is a graph showing the amount of deformation in Experimental Example 14.

FIG. 20 is a plan view of a rotary deflector used in the third embodiment.

FIG. 21 is a graph showing the amount of deformation in Experimental Example 15.

22 is a graph showing the amount of deformation in Experimental Example 16.

23 is a graph showing the amount of deformation in Experimental Example 17.

FIG. 24 is a plan view of a rotary deflector used in the fourth embodiment.

FIG. 25 is a graph showing the amount of deformation in Experimental Example 18.

26 is a graph showing the amount of deformation in Experimental Example 19.

FIG. 27 is a perspective view of a light beam scanning device according to a fifth embodiment.

FIG. 28 is a plan view of a light beam scanning device according to a fifth embodiment.

FIG. 29 is a front view of a light beam scanning device according to a fifth embodiment.

FIG. 30 is a perspective view of a light beam scanning device according to a sixth embodiment.

FIG. 31 is a plan view of a light beam scanning device according to a sixth embodiment.

FIG. 32 is a front view of a light beam scanning device according to a sixth embodiment.

FIG. 33 is a perspective view of a light beam scanning device according to a seventh embodiment.

FIG. 34 is a plan view of a light beam scanning device according to a seventh embodiment.

FIG. 35 is a front view of a light beam scanning device according to a seventh embodiment.

FIG. 36 is a perspective view of a light beam scanning device according to an eighth embodiment.

FIG. 37 is a plan view of a light beam scanning device according to an eighth embodiment.

FIG. 38 is a front view of the light beam scanning device of the eighth embodiment.

FIG. 39 is a perspective view of a light beam scanning device of the ninth embodiment.

FIG. 40 is a plan view of a light beam scanning device according to a ninth embodiment.

FIG. 41 is a front view of a light beam scanning device of the ninth embodiment.

FIG. 42 is a perspective view of a light beam scanning device of the tenth embodiment.

FIG. 43 is a plan view of a light beam scanning device which is a tenth embodiment.

FIG. 44 is a front view of a light beam scanning device according to a tenth embodiment.

FIG. 45 is a perspective view of a light beam scanning device of the eleventh embodiment.

FIG. 46 is a plan view of a light beam scanning device of the eleventh embodiment.

FIG. 47 is a front view of a light beam scanning device of the eleventh embodiment.

[Explanation of symbols]

15, 30, 35, 40, 52, 55 ... Rotating deflector 5 ... Motor 8 ... Rotating shaft 10, 62 ... Pedestal 20, 63, 65, 67, 72, 74, 76, 82 ... Fixing tool 64, 66, 68 , 73, 75, 77, 83 ... Projection pieces

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Etsuko Shibata 2-3-13 Azuchi-cho, Chuo-ku, Osaka-shi, Osaka, Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Masanori Yamamoto Azuchi, Chuo-ku, Osaka-shi, Osaka 2-13-3 Machi, Osaka International Building Minolta Camera Co., Ltd. (72) Inventor, Kenji Hamada 2-3-13 Azuchi-cho, Chuo-ku, Osaka City, Osaka Prefecture International Building Minolta Camera Co., Ltd.

Claims (20)

[Claims] 1. A light beam scanning device for deflecting a light beam by a constant speed rotation of a rotary deflector to scan on a light receiving surface, wherein the rotary deflector comprises a resin material as a main component and has a plurality of outer peripheral surfaces. A regular polygon having a deflecting surface is formed, the thickness in the vicinity of the deflecting surface is larger than the thickness in the vicinity of the center of rotation, and the rotary deflector is integrally attached to the rotary shaft of a motor via a pedestal. A light beam scanning device characterized by the above. 2. A light beam scanning device for deflecting a light beam by a constant speed rotation of a rotary deflector and scanning the light receiving surface, wherein the rotary deflector comprises a resin material as a main component and has a plurality of outer peripheral surfaces. Forming a regular polygon having a deflecting surface, the thickness in the diagonal direction is smaller than the thickness in the deflecting surface direction, and the rotary deflector is integrally attached to the rotary shaft of the motor via a pedestal, A light beam scanning device characterized by the above. 3. A light beam scanning device which deflects a light beam by a constant speed rotation of a rotary deflector and scans on a light receiving surface, wherein the rotary deflector is composed of a resin material as a main component and has a plurality of outer peripheral surfaces. A regular polygon having a deflecting surface, the physical properties of which differ in the vicinity of the deflecting surface and other portions, and the rotary deflector is integrally attached to the rotary shaft of the motor via a pedestal, And a light beam scanning device. 4. The rotary deflector is a regular polygon having four or less faces, and is composed of a first material in a diagonal direction and a second material in a deflecting surface direction, and the Young's modulus of the first material is that of the second material. The light beam scanning device according to claim 3, wherein the light beam scanning device has a Young's modulus larger than the Young's modulus. 5. The rotary deflector is a regular polygon having six or more faces, and is composed of a first material in a diagonal direction and a second material in a deflecting surface direction, and the Young's modulus of the second material is that of the first material. The light beam scanning device according to claim 3, wherein the light beam scanning device has a Young's modulus larger than the Young's modulus. 6. The rotary deflector is a regular polygon having four or less faces, and is composed of a first material in a diagonal direction and a second material in a deflecting surface direction, and the specific gravity of the first material is the specific gravity of the second material. The light beam scanning device according to claim 3, wherein the light beam scanning device is smaller than 7. The rotary deflector is a regular polygon having 6 or more faces, and is composed of a first material in a diagonal direction and a second material in a deflecting surface direction, and a specific gravity of the second material is a specific gravity of the first material. The light beam scanning device according to claim 3, wherein the light beam scanning device is smaller than 8. The rotary deflector comprises a first material forming a peripheral portion including a deflecting surface and a second material forming a central portion, and Young's modulus of the first material is Young's modulus of the second material. The light beam scanning device according to claim 3, wherein the light beam scanning device is larger than the above. 9. A rotary deflector comprising a resin material as a main component and forming a regular polygonal body having a plurality of deflection surfaces on its outer peripheral surface, a motor having a rotary shaft for rotating the rotary deflector, and the motor. And a mounting member for fixing the rotary deflector mounted on the pedestal on the pedestal, wherein the mounting member has a number of deflection surfaces and Having the same or an integer multiple of the projecting pieces, the projecting pieces pierce the rotary deflector to press the rotary deflector onto the pedestal and suppress deformation of each deflecting surface during rotation. Characteristic light beam scanning device. 10. The rotary deflector is a regular polygon having four or less faces, and the pressing position of each protrusion of the mounting member is set at least on a diagonal line connecting each corner of the rotary deflector and the rotation center. 10. The light beam scanning device according to claim 9, wherein: 11. The rotary deflector is a regular polygon having six or more surfaces, and the pressing position of each protrusion of the mounting member is at least on a straight line connecting the central portion of each deflecting surface of the rotary deflector and the rotation center. 10. The light beam scanning device according to claim 9, wherein 12. A rotary deflector which is composed of a resin material as a main component and which is a regular polygon having a plurality of deflection surfaces on its outer peripheral surface, a motor having a rotary shaft for rotating the rotary deflector, and the motor. And a mounting member for fixing the rotary deflector mounted on the pedestal on the pedestal, wherein the mounting member has a number of deflection surfaces and The same number or an integral multiple of protrusions are provided, and the protrusions engage with the outer peripheral edge of the rotary deflector to press the rotary deflector onto the pedestal and to deform each deflection surface during rotation. A light beam scanning device characterized by: 13. The rotary deflector is a regular polygon having four or less faces, and the engagement position of each protrusion of the mounting member is set at least at each corner of the rotary deflector. The light beam scanning device according to claim 12. 14. The rotary deflector is a regular polygon having six or more surfaces, and the engagement position of each protrusion of the mounting member is set at least at the central edge portion of each deflecting surface of the rotary deflector. The light beam scanning device according to claim 12. 15. A rotary deflector which is made of a resin material as a main component and has a regular polygonal shape having a plurality of deflection surfaces on its outer peripheral surface, a motor having a rotary shaft for rotating the rotary deflector, and the motor. And a mounting member for fixing the rotary deflector mounted on the pedestal onto the pedestal, the pedestal and the mounting member being surfaces of deflection surfaces. The number of projections is the same as or an integer multiple of the number, and the projections pierce the front and back surfaces of the rotary deflector to hold the rotary deflector,
A light beam scanning device characterized by suppressing deformation of each deflecting surface during rotation. 16. The rotary deflector is a regular polygon having four or less faces, and the pressing positions of the protrusions of the pedestal and the mounting member are at least on a diagonal line connecting each corner of the rotary deflector and the rotation center. The light beam scanning device according to claim 15, wherein the light beam scanning device is set. 17. The rotary deflector is a regular polygon having six or more surfaces, and the pressing positions of the protrusions of the pedestal and the mounting member are at least the central portion and the center of rotation of each deflecting surface of the rotary deflector. The light beam scanning device according to claim 15, wherein the light beam scanning device is set on a connecting straight line. 18. A rotary deflector which is made of a resin material as a main component and has a regular polygonal shape having a plurality of deflection surfaces on its outer peripheral surface, a motor having a rotary shaft for rotating the rotary deflector, and the motor. And a mounting member for fixing the rotary deflector mounted on the pedestal on the pedestal, the pedestal and the mounting member being surfaces of deflection surfaces. The number of projections is the same as or an integer multiple of the number, and the projections engage the outer peripheral edge of the rotary deflector to hold the rotary deflector and suppress deformation of each deflecting surface during rotation. A light beam scanning device characterized by: 19. The rotary deflector is a regular polygon having four or less faces, and the engagement positions of the protrusions of the pedestal and the mounting member are set at least at the corners of the rotary deflector. 19. The light beam scanning device according to claim 18, which is characterized in that. 20. The rotary deflector is a regular polygon having 6 or more surfaces, and the engagement positions of the protrusions of the pedestal and the mounting member are set at least at the central edge portion of each deflecting surface of the rotary deflector. 19. The light beam scanning device according to claim 18, wherein: