JP2007163944A - Polygonal scan mirror rotary drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polygonal scan mirror rotary drive device in which errors in assembly can be reduced as compared with conventional devices. <P>SOLUTION: The polygonal scan mirror rotary drive device comprises: an enclosure 1 of which inside space is substantially pillar-shaped for housing a polygonal scan mirror 5 and a drive unit 4 for rotating the scan mirror; a lid 2 for closing the upper part of the enclosure 1; a plurality of screw holes 9a, 9b, and 9c provided to the enclosure 1 at the rotationary-symmetric position with reference to the central axis for fixing the lid 2; and a plurality of protrusion members 7a, 7b, and 7c for suppressing the upper movement of the polygonal scan mirror 5 during the rotary drive of the polygonal scan mirror 5. The protrusion members 7a, 7b, and 7c are provided in such a manner that the relative positions of the screw holes 9a, 9b, and 9c, and the protrusion members 7a, 7b, and 7c are substantially the same at all the possible fitting positions where the lid 2 is fitted to the enclosure 1 by screws. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polygonal scanning mirror rotation driving device used as an optical scanning device in an image forming apparatus.

  An image forming apparatus such as a printer is provided with a polygon mirror rotation driving device for performing optical scanning, as shown in an external view of FIG. FIG. 17 is a cross-sectional configuration diagram taken along the line BB ′ in FIG. As shown in FIG. 17, the polygon mirror rotation driving apparatus includes a polygon mirror 100, a rotor 101 for rotationally driving the polygon mirror 100, and a casing 102 for housing the polygon mirror 100 and the rotor 101. . Furthermore, a lid 103 for sealing the housing 102 is provided. The lid 103 is provided to silence the sound emitted from the polygon mirror 100 that rotates at high speed.

  When the polygon mirror 100 is rotationally driven in such a sealed space, the polygon mirror 100 may float because the negative pressure generated above and below the polygon mirror 100 is different.

In order to prevent the polygon mirror 100 from being lifted, a polygon mirror rotation driving device is disclosed in which an air flow suppression plate 104 is provided as a protruding member inside the lid 103 as shown in FIG. 1).
Utility Model Registration No. 2569244

  However, the document 1 discloses that the air flow suppression plate 104 is useful for preventing the polygon mirror 100 from being lifted, but describes the means for attaching the lid 103 and the housing 102. Not. However, such a lid 103 is generally attached to the housing 102 by screws.

  FIG. 19 shows a case where the conventional structure of FIG. 18 is assumed to be attached with screws.

  Here, FIG. 19 is a plan view of an example of the polygon mirror rotation driving device. The polygon mirror rotation driving device shown in FIG. 19 is provided in the housing 102 and includes three housing-side screw holes 107 formed symmetrically about rotation about the center axis 105 of the lid 103 and the housing 102. Yes. In addition, three lid-side screw holes 108 are formed in the lid 103 so as to be rotationally symmetrical three times about the central axis 105. In addition, four air flow suppression plates 104 are provided with four-fold rotational symmetry about the central axis 105. By arranging the air flow suppression plate 104 with the housing side screw hole 107 as a reference as shown in FIG. 19, the polygon mirror 100 can be effectively prevented from being lifted.

  However, since the lid 103 can be attached to the housing 102 at three different positions, the attachment direction of the lid 103 is mistaken in the production process, for example, the attachment position of the lid 103 is rotated by 120 degrees in the arrow S direction. 20, as shown in FIG. 20, the relative position of the air flow suppressing plate 104 with respect to the housing side screw hole 107 and the glass window 99 may be different as compared to the case of FIG. 19. The present inventor has realized that a problem arises that the lifting cannot be effectively prevented.

  That is, the lid 103 is made of aluminum die-casting from the viewpoint of heat dissipation, and since it is not transparent, it is extremely troublesome for the operator to assemble while checking the regular mounting position from three mounting positions. There is a problem that assembly errors are likely to occur during production.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a polygonal scanning mirror rotation drive device that can suppress the occurrence of assembly errors as compared with the conventional art.

In order to achieve the above object, the first present invention provides:
A polygon scanning mirror;
A drive unit for rotating the polygon scanning mirror;
A housing for accommodating the polygon scanning mirror and the drive unit, the inner space being substantially cylindrical,
A lid for closing the top of the housing;
In order to fix the lid, the housing, the plurality of screw holes provided in a rotationally symmetric position with respect to the central axis,
A plurality of projecting members for suppressing upward movement of the polygon scanning mirror when the polygon scanning mirror is driven to rotate;
The protruding member is provided so that the relative positional relationship between the screw hole and the protruding member is substantially the same at all mounting positions that can be mounted when the lid is screwed to the housing. Polygonal scanning mirror rotation drive device.

The second aspect of the present invention
The protruding member is the polygonal scanning mirror rotation driving device according to the first aspect of the present invention, which is provided inside the lid so as to protrude toward the polygonal scanning mirror.

The third aspect of the present invention
The plurality of projecting members are provided at rotationally symmetric positions with respect to the central axis,
In the polygon scanning mirror rotation driving device according to the second aspect of the present invention, the number of the protruding members is the same as or an integral multiple of the number of the screw holes.

The fourth aspect of the present invention is
A polygon scanning mirror;
A drive unit for rotating the polygon scanning mirror;
A housing for accommodating the polygon scanning mirror and the drive unit, the inner space being substantially cylindrical,
A lid for closing the top of the housing;
A projecting member for suppressing upward movement of the polygon scanning mirror when the polygon scanning mirror is driven to rotate;
The protruding member is a polygonal scanning mirror rotation driving device provided on the inner surface of the casing so as to protrude toward the central axis of the casing.

  According to the present invention, it is possible to provide a polygonal scanning mirror rotation driving device that can suppress the occurrence of assembly errors as compared with the prior art.

  A polygon mirror rotation driving device as an embodiment of a polygon scanning mirror rotation driving device according to the present invention will be described below.

(Embodiment 1)
FIG. 1 is an external view of the polygon mirror rotation driving apparatus according to the first embodiment. The polygon mirror rotation driving device according to the first embodiment includes a casing 1 having a substantially cylindrical inner space, a substantially circular lid 2 provided on the top of the casing 1, and a side surface of the casing 1. And a glass window 3 through which light enters and exits.

  FIG. 2 is a schematic configuration diagram of the AA ′ cross section of FIG. 1. A rotor 4 is disposed at the bottom of the casing 1, and a polygon mirror 5 is provided directly connected to the rotor 4. A projecting member 7 is provided below the lid 2 so as to project toward the polygon mirror 5 side.

  FIG. 3 is a plan view of the polygon mirror rotation driving device according to the first embodiment with the lid removed. As shown in FIG. 3, the polygon mirror 5 has a regular octagonal shape when viewed from above. The housing 1 is provided with three housing-side screw holes 9a, 9b, 9c having the same diameter at 120 ° intervals about the shaft 8 in order to insert screws. Note that the housing side screw hole disposed on the central axis 3a of the glass window 3 and facing the glass window 3 is 9a, and the screw holes are arranged clockwise from the housing side screw hole 9a in order. Are 9b and 9c. Further, the housing side screw holes 9a, 9b, 9c are provided in convex portions 1a, 1b, 1c protruding inward from the inner side surface 1d of the housing 1.

  FIG. 4 is a plan view of the lid of the polygon mirror rotation driving device according to the first embodiment. The lid 2 is provided with three lid-side screw holes 6 a, 6 b, 6 c for fixing to the housing 1 in the vicinity of the outer periphery of the lid 2 at intervals of 120 degrees with the shaft 8 as the center. Further, the three projecting members 7a, 7b, 7c are provided on the inner peripheral side with respect to the position of the lid-side screw holes 6a, 6b, 6c at intervals of 120 degrees with the shaft 8 as the center. The projecting members 7a, 7b, and 7c are provided at positions rotated by a predetermined angle θ ° in the clockwise direction from the positions of the lid-side screw holes 6a, 6b, and 6c. The lid-side screw holes 6a, 6b, 6c have the same diameter. Further, the protruding members 7a, 7b, and 7c have the same shape, and are attached so as to be rotationally symmetric about the shaft 8 not only in their positions but also in the attaching direction.

  That is, the lid-side screw holes 6a, 6b, 6c are formed at positions that are rotationally symmetrical three times with the shaft 8 as a rotation axis, and the protruding members 7a, 7b, 7c rotate three times around the shaft 8. They are arranged symmetrically.

  FIG. 5 is a plan view of the polygon mirror rotation driving apparatus according to the first embodiment. As shown in FIG. 5, the lid-side screw hole 6a matches the casing-side screw hole 9a, the lid-side screw hole 6b matches the casing-side screw hole 9b, and the lid-side screw hole 6c matches the casing-side screw hole 9c. The lid 2 is attached to the housing 1.

  In the polygon mirror rotation driving device of the first embodiment, the protruding members 7a, 7b, 7c are arranged at predetermined positions with reference to the housing side screw holes 9a, 9b, 9c as shown in FIG. Therefore, the difference in the negative pressure between the upper and lower sides of the polygon mirror 5 can be reduced, and the floating can be prevented.

  An example of the polygon scanning mirror of the present invention corresponds to the polygon mirror 5 of the first embodiment, and an example of the drive unit of the present invention corresponds to the rotor 4 of the first embodiment. An example of the plurality of screw holes of the present invention corresponds to the housing side screw holes 9a, 9b, 9c of the first embodiment.

  In the manufacturing process of the polygon mirror rotation driving device having the above-described configuration, when the lid 2 is fixed to the casing 1 in which the rotor 4 and the polygon mirror 5 are accommodated, the lid-side screw holes 6a, 6b, 6c are connected to the shaft 8. Since it is arranged so as to be rotationally symmetrical three times as a rotation axis, it can be attached to the housing 1 at three different positions when the housing side screw holes 9a, 9b, 9c are used as a reference. .

  FIG. 6 shows a plan view when the lid 2 is attached by being rotated 120 degrees. As shown in FIG. 6, in the case of being shifted 120 degrees clockwise, the lid side screw hole 6a is in the housing side screw hole 9b, the lid side screw hole 6b is in the housing side screw hole 9c, and the lid side screw 6c is. Is attached to the housing-side screw hole 9a.

  As described above, even when the housing 1 is fixed and the lid 2 is rotated and attached, in the first embodiment, the projecting members 7a, 7b, and 7c are rotationally symmetric about the axis 8 three times. Therefore, the positions of the protruding members 7a, 7b, and 7c do not change with respect to the housing-side screw holes 9a, 9b, and 9c. Since the positions of the housing side screw holes 9a, 9b, 9c are arranged with reference to the glass window 3, it can be said that the positions of the protruding members 7a, 7b, 7c do not change with respect to the glass window 3.

  As described above, even when the lid 2 is attached to the housing 1 at three different positions, the relative positional relationship between the housing-side screw holes 9a, 9b, 9c and the protruding members 7a, 7b, 7c is substantially reduced. It will be the same.

  Therefore, even when the lid 2 is attached at a different position, the projecting member can be arranged at a predetermined position, so that the effect of preventing the polygon mirror from being lifted can be exhibited. Therefore, it becomes possible to suppress the attachment mistake of the lid | cover 2 in a manufacturing process.

  In the first embodiment, the projecting members 7a, 7b, 7c are provided at positions rotated by θ degrees with respect to the positions of the lid-side screw holes 6a, 6b, 6c, but are provided at the rotated positions. Instead, the arrangement shown in FIG. 7 may be used.

  FIG. 7 is a plan view of the lid 2, and FIG. 8 is a perspective view of the lid 2 as viewed from below.

  In the lid 2 shown in FIG. 7, projecting members 7a, 7b, and 7c are arranged on the straight line connecting the lid-side screw holes 6a, 6b, and 6c and the shaft 8 so as to be three-fold rotationally symmetric. In the case of such a configuration as well, it is possible to eliminate an error in attaching the lid as described above.

  In the first embodiment, the cover 2 is provided with three housing-side screw holes and three projecting members, but the present invention is not limited to this configuration.

  For example, four screw holes may be provided with rotational symmetry about the shaft 8, and eight projecting members may be provided at rotationally symmetrical positions with respect to the shaft 8. Thus, it is desirable that the number of projecting members is an integral multiple of the number of screw holes, and that each is provided rotationally symmetrically about the axis. For example, when the angle between the protruding member 7a and the protruding member 7b is 120 degrees, the angle between the protruding member 7b and the protruding member 7c is 150 degrees, and the angle between the protruding member 7c and the protruding member 7a is 90 degrees. Can be said to be one-time rotationally symmetric, but is defined as not rotationally symmetric in the claims and in this specification.

  In the first embodiment, the projecting members 7a, 7b, and 7c are formed in an arc shape along the outer peripheral edge of the lid 2, but may have a rectangular parallelepiped shape. It is not limited.

  In short, it is only necessary that the protruding members are provided so that the relative positional relationship with the screw holes is substantially the same at the attachment positions of a plurality of different lids.

(Embodiment 2)
The polygon mirror rotation driving device according to the second embodiment of the present invention has the same basic configuration as that of the first embodiment, but the protrusion member is a housing side screw of the housing 1 as compared with the first embodiment. The difference is that the holes 9a, 9b and 9c are provided on the inner surface. Therefore, this difference will be mainly described. In addition, the same code | symbol is attached | subjected about the component same as Embodiment 1. FIG.

  FIG. 9 is a side configuration diagram of the polygon mirror rotation driving apparatus according to the second embodiment, and FIG. 10 is a plan view of the polygon mirror rotation driving apparatus according to the second embodiment with the lid removed. As shown in FIGS. 9 and 10, the polygon mirror rotation driving device of the second embodiment is provided with housing side screw holes 9 a and 9 b instead of the protruding members 7 provided on the lid 2 described in the first embodiment. , 9c is provided with a protruding member 13 protruding toward the shaft 8 from the convex portions 1a, 1b, 1c.

  In the second embodiment, since the protruding member 13 of the present invention is provided in the casing 1, even when the lid 2 is attached to three different positions, the casing-side screw holes 9a, 9b, Since the arrangement of the protruding members 13 does not change with respect to 9c, there is no mistake in attaching the lid.

  In addition, although the protruding member 13 in the second embodiment is provided on the convex portions 1a, 2a, and 3a, no mistake in attaching the lid occurs regardless of the position on the inner surface of the housing 1. Needless to say. Furthermore, the positions of the housing-side screw holes 9a, 9b, 9c and the lid-side screw holes 6a, 6b, 6c may not be provided rotationally symmetrically about the shaft 8.

  In the second embodiment, the protruding member 13 is separately provided, but the protruding portions 1a, 2a, and 3a may be formed so as to protrude in the direction of the axis 8.

  Further, it may be a polygon mirror rotation driving device configured as shown in the plan view of FIG. FIG. 11 is a plan view of the state with the lid removed. In the polygon mirror rotation driving device shown in FIG. 11, the housing side screw holes 9 a, 9 b, 9 c are arranged on the outer peripheral side of the inner surface of the housing 1. Protrusions 1a, 1b, and 1c for forming the case-side screw holes 9a, 9b, and 9c project to the outer peripheral side. A protruding member 13 is arranged on the inner surface of the housing 1 in which the housing-side screw holes 9a, 9b, 9c are formed, as in FIG. Further, in the configuration shown in FIG. 11, it goes without saying that no matter what the position of the projecting member 13 is provided on the inner side surface of the housing 1, there is no mistake in attaching the lid.

(Reference Example 1)
Hereinafter, a polygon mirror rotation driving device of Reference Example 1, which is an example of a technology related to the present invention, will be described with reference to FIGS. 12 and 13.

  The polygon mirror rotation driving device of the first reference example has the same basic configuration as that of the first embodiment, except that the marker is formed on the lid 2 and the projecting members 7a, 7b, 7c are on the shaft 8. The difference is that they are not rotationally symmetric. In addition, the same code | symbol is attached | subjected to the component same as Embodiment 1. FIG.

  FIG. 12 is a perspective view of the polygon mirror rotation driving device of the first reference example. As shown in FIG. 12, an arrow-like marker 12 facing the glass window 3 is formed on the lid 2. FIG. 13 is a plan view of the polygon mirror rotation driving device of the first reference example. As shown in FIG. 13, the projecting members 7a, 7b, and 7c of Reference Example 1 are not provided rotationally symmetric, the angle between the projecting member 7a and the projecting member 7b is 120 degrees, and the projecting member 7b and the projecting member. The angle between 7c is 155 degrees, and the angle between the protruding member 7c and the protruding member 7a is 85 degrees. With such an arrangement of the protruding members 7a, 7b, and 7c, the polygon mirror rotation driving device of the first reference example has an effect of preventing the polygon mirror from being lifted.

  Also in the manufacturing process of the polygon mirror rotation driving device in the present reference example 1, the lid 2 can be attached to the housing 1 at three different positions as in the first embodiment. Unlike the first embodiment, the projecting members 7a, 7b, and 7c are not rotationally symmetric about the shaft 8, so that the projecting member 7a with the housing side screw holes 9a, 9b, and 9c as a reference, depending on the mounting position of the lid 2. , 7b, 7c are different from each other.

  Here, when the polygon mirror rotation drive device is assembled, the lid 2 is assembled to the housing 1 so that the direction of the arrow of the marker 12 is directed to the glass window 3, so that one of the three attachment positions can be determined. I can do it.

  For this reason, in Reference Example 1, it is possible to prevent the attachment position of the lid 2 to the housing 1 from being wrong.

  In the first reference example, the position of the protruding member 7 is not provided at a rotationally symmetric position around the axis 8, but may be provided at a rotationally symmetric position. As shown in FIG. 20 of the related art, even if the position is rotationally symmetric, if the number of projecting members is not an integral multiple of the screw hole, the housing side screw holes 9a and 9b depend on the mounting position of the lid 2. , 9c, the marker of this reference example 1 is useful.

As described above, the invention taking the above reference example as an example,
A polygon scanning mirror, and a rotation drive unit for rotating the polygon scanning mirror;
A housing for accommodating the polygon scanning mirror and the drive unit, the inner space being substantially cylindrical,
A lid for closing the top of the housing;
In order to fix the lid, the housing, the plurality of screw holes provided in a rotationally symmetric position with respect to the central axis,
A plurality of projecting members provided on the inner side of the lid so as to protrude in the direction of the polygon scanning mirror in order to suppress the upward movement of the polygon scanning mirror when the polygon scanning mirror is rotationally driven. When,
A polygonal scanning mirror rotation driving device comprising: a marker formed on the lid to indicate a direction of attachment to the housing.

  Furthermore, it is preferable that the lid is integrally formed with the protruding member and the marker.

(Reference Example 2)
Hereinafter, a polygon mirror rotation driving device of Reference Example 2, which is an example of a technology related to the present invention, will be described with reference to FIG.

  The polygon mirror rotation drive device of the present reference example 2 has the same basic configuration as that of the reference example 1, but is different from the reference example 1 in that the marker 12 is not formed and the diameter of one screw hole. Is different from other screw holes. Therefore, this difference will be mainly described. In addition, the same code | symbol is attached | subjected to the component same as the reference example 1. FIG.

  FIG. 14 is a plan view of the polygon mirror rotation driving device according to the second embodiment. As shown in FIG. 14, in Reference Example 2, the housing-side screw hole 9a ′ of the housing 1 is smaller than the other housing-side screw holes 9b and 9c, and the positions corresponding thereto. The diameter of the lid side screw hole 6a 'of the lid 2 is also smaller than that of the lid side screw holes 6b and 6c. Accordingly, a screw 10 ′ having a smaller diameter than the screw 10 is attached to the lid-side screw hole 6 a ′ and the housing-side screw hole 9 a ′.

  In the present reference example 2, the lid 2 can be attached to the housing 1 only at one attachment position, so that an attachment error of the lid 2 can be suppressed.

As described above, the invention taking the above reference example as an example,
A polygon scanning mirror;
A drive unit for rotating the polygon scanning mirror;
A housing for housing the polygon scanning mirror and the drive unit;
A lid for closing the top of the housing;
The plurality of screw holes for fixing the lid provided in the housing; and
A plurality of projecting members provided on the inner side of the lid so as to protrude in the direction of the polygon scanning mirror in order to suppress the upward movement of the polygon scanning mirror when the polygon scanning mirror is rotationally driven. And comprising
The plurality of screw holes are polygon scanning mirror rotation driving devices in which one screw hole having a different diameter is included.

  The screw holes having different diameters are more preferably smaller in diameter than the other plurality of screw holes.

(Reference Example 3)
Hereinafter, a polygon mirror rotation driving device of Reference Example 3, which is an example of a technology related to the present invention, will be described with reference to FIG.

  The polygon mirror rotation drive device in the present reference example 3 has the same basic configuration as that of the reference example 1, but compared with the reference example 1, the marker 12 is not formed and the screw hole is centered on the axis. Is different in that it is not rotationally symmetrical. Therefore, this difference will be mainly described. In addition, the same code | symbol is attached | subjected to the component same as the reference example 1. FIG.

  FIG. 15 is a plan view of the polygon mirror rotation driving device of the third embodiment. As shown in FIG. 15, in this reference example 3, in addition to the housing side screw holes 9a, 9b, 9c of the housing 1, a housing side screw hole 9d is provided between 9a, 9b. A corresponding screw hole 6d of the lid 2 is also provided.

  In this reference example 3, since the lid side screw holes 6a, 6b, 6c, 6d corresponding to the housing side screw holes 9a, 9b, 9c, 9d are not provided rotationally symmetrically about the axis 8, the lid 2 is Since it can be mounted only at the street mounting position, it is possible to suppress the mounting error of the lid 2.

As described above, the invention taking the above reference example as an example,
A polygon scanning mirror;
A drive unit for rotating the polygon scanning mirror;
A housing for accommodating the polygon scanning mirror and the drive unit, the inner space being substantially cylindrical,
A lid for closing the top of the housing;
A plurality of housing-side screw holes for fixing the lid provided in the housing;
A plurality of lid-side screw holes provided in the lid so as to correspond to the plurality of screw holes;
A plurality of projecting members provided on the inner side of the lid so as to protrude in the direction of the polygon scanning mirror in order to suppress the upward movement of the polygon scanning mirror when the polygon scanning mirror is rotationally driven. And comprising
The plurality of housing-side screw holes are polygon scanning mirror rotation driving devices provided at rotationally asymmetric positions with respect to a central axis of the housing.

  The polygonal scanning mirror rotation driving device of the present invention has an effect that an assembly error can be suppressed as compared with the conventional one, and is useful as a polygonal scanning mirror rotation driving device used for an image forming apparatus or the like.

1 is an external view of a polygon mirror rotation driving device according to a first embodiment of the present invention. 1 is a cross-sectional configuration diagram of a polygon mirror rotation driving device according to a first embodiment of the present invention. The top view of the state which removed the cover of the polygon mirror rotation drive device in Embodiment 1 concerning this invention The top view of the lid | cover of the polygon mirror rotational drive apparatus in Embodiment 1 concerning this invention 1 is a plan view of a polygon mirror rotation driving device according to a first embodiment of the present invention. The top view of the state which rotated the lid | cover 120 degree | times in the polygon mirror rotational drive apparatus in Embodiment 1 concerning this invention. The top view of the modification of the polygon mirror rotation drive device in Embodiment 1 concerning this invention External view of the lid of the polygon mirror rotation driving device in the modification of the first embodiment according to the present invention Sectional block diagram of the polygon mirror rotation drive apparatus in Embodiment 2 concerning this invention The top view of the state which removed the cover of the polygon mirror rotation drive device in Embodiment 2 concerning this invention The top view of the state which removed the cover of the polygon mirror rotation drive device in the modification of Embodiment 2 concerning this invention 1 is an external view of a polygon mirror rotation driving device in Reference Example 1 which is an example of an invention related to the present invention. The top view of the polygon mirror rotation drive device in the reference example 1 which is an example of the invention relevant to this invention The top view of the polygon mirror rotational drive apparatus in the reference example 2 which is an example of the invention relevant to this invention The top view of the polygon mirror rotational drive apparatus in the reference example 3 which is an example of the invention relevant to this invention External view of conventional polygon mirror rotation drive device Cross-sectional configuration diagram of a conventional polygon mirror rotation drive device Cross-sectional configuration diagram of a conventional polygon mirror rotation drive device Plan view of conventional polygon mirror rotation drive device Plan view when the mounting position of the lid of the conventional polygon mirror rotation drive device is changed

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case 2 Cover 3 Glass window 4 Rotor 5 Polygon mirror 6a, 6b, 6c Cover side screw hole 7a, 7b, 7c Projection member 8 Shaft 9a, 9b, 9c Case side screw hole 10 Screw

Claims (4)

A polygon scanning mirror;
A drive unit for rotating the polygon scanning mirror;
A housing for accommodating the polygon scanning mirror and the drive unit, the inner space being substantially cylindrical,
A lid for closing the top of the housing;
In order to fix the lid, the housing, the plurality of screw holes provided in a rotationally symmetric position with respect to the central axis,
A plurality of projecting members for suppressing upward movement of the polygon scanning mirror when the polygon scanning mirror is driven to rotate;
The protruding member is provided so that the relative positional relationship between the screw hole and the protruding member is substantially the same at all mounting positions that can be mounted when the lid is screwed to the housing. Polygonal scanning mirror rotation drive device.   The polygonal scanning mirror rotation driving device according to claim 1, wherein the protruding member is provided inside the lid so as to protrude toward the polygonal scanning mirror. The plurality of projecting members are provided at rotationally symmetric positions with respect to the central axis,
The polygon scanning mirror rotation driving device according to claim 2, wherein the number of the projecting members is the same as or an integral multiple of the number of the screw holes. A polygon scanning mirror;
A drive unit for rotating the polygon scanning mirror;
A housing for accommodating the polygon scanning mirror and the drive unit, the inner space being substantially cylindrical,
A lid for closing the top of the housing;
A projecting member for suppressing upward movement of the polygon scanning mirror when the polygon scanning mirror is driven to rotate;
The polygonal scanning mirror rotation drive device, wherein the protruding member is provided on the inner surface of the casing so as to protrude toward the central axis of the casing.