JP2020052266A - Optical scanning device - Google Patents

Abstract

To miniaturize an optical scanning device in a direction along a rotation axis.SOLUTION: An optical scanning device 1 includes: a polygon mirror 40 for deflecting light beams (laser beams LY to LK) emitted from a light source; a motor PM for driving the polygon mirror 40; a first scanning lens 50 through the light beam deflected by the polygon mirror 40 passes; a housing 100 which has a bottom wall 110 and a side wall 120, and which supports the first scanning lens 50; a lid 200 positioned on an opposite side of the bottom wall 110 across the first scanning lens 50; and a support frame 300 which is supported by the housing 100, and which has a base 310 supporting the motor PM at a position separated from the bottom wall 110. The polygon mirror 40 is arranged between the bottom wall 110 and the base 310. A distance from the bottom wall 110 to the polygon mirror 40 is smaller than a distance from the base 310 to the polygon mirror 40.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical scanning device provided with a polygon mirror.

  2. Description of the Related Art Conventionally, an optical scanning device including a light source, a polygon mirror that deflects a light beam emitted from the light source, a motor that drives the polygon mirror, and a housing having a bottom wall and a side wall is known. Reference 1). In this technique, the motor is fixed to the bottom wall of the housing, so that the motor is arranged between the polygon mirror and the bottom wall.

JP 2007-178605 A

  However, since the size of the motor in the direction along the rotation axis is large, it is necessary to secure a certain height from the bottom surface of the housing to the optical axis. There is a problem that it is difficult to reduce the size.

  Accordingly, an object of the present invention is to reduce the size of the optical scanning device in a direction along the rotation axis.

In order to solve the above problem, an optical scanning device according to the present invention includes a light source, a polygon mirror that deflects a light beam emitted from the light source, a motor that rotates the polygon mirror around a rotation axis, and the polygon. A first scanning lens through which the light beam deflected by the mirror passes, a bottom wall and a side wall, and a housing supporting the first scanning lens; and a side opposite to the bottom wall with the first scanning lens interposed therebetween. And a lid located thereon.
The optical scanning device further includes a support frame that is supported by the housing and has a base that supports the motor at a position away from the bottom wall.
The polygon mirror is disposed between the bottom wall and the base.
The distance from the bottom wall to the polygon mirror is smaller than the distance from the base to the polygon mirror.

  According to this configuration, since the light beam deflected by the polygon mirror can be made closer to the bottom wall, the size of the optical scanning device can be reduced in the direction along the rotation axis.

  Further, the base may be fastened to the housing at a position corresponding to a vertex of a polygon surrounding the rotation axis when viewed from a direction along the rotation axis.

  According to this, since the base of the support frame can be firmly fixed to the housing, vibration of the polygon mirror can be suppressed.

  Further, the housing may have a protruding portion that protrudes from the bottom wall and supports the support frame, and a protruding distance of the protruding portion may be greater than a distance from the bottom wall to the polygon mirror. .

  Further, the motor may be fastened to the base at a position corresponding to a vertex of a polygon surrounding the rotation axis when viewed from a direction along the rotation axis.

  According to this, since the motor can be firmly fixed to the base, vibration of the polygon mirror can be suppressed.

  Further, the support frame has an extending portion disposed between the polygon mirror and the first scanning lens and extending from the base toward the bottom wall when viewed from a direction along the rotation axis. You may.

  According to this, the rigidity of the base can be increased by the extension. Further, since the light reflected in an unintended direction by the polygon mirror can be absorbed by the extension provided between the polygon mirror and the first scanning lens, stray light in the housing can be suppressed. it can.

  The distance from the tip of the extension to the bottom wall is smaller than the distance from the polygon mirror to the bottom wall, and the extension has a first opening through which light deflected by the polygon mirror passes. May be provided.

  According to this, while the light beam deflected by the polygon mirror is passed through the first opening of the extension portion, stray light of the light beam can be blocked by the extension portion.

  Further, the bottom wall may have a second opening for passing a light beam out of the housing, and may further include a reflection mirror for reflecting the light beam toward the second opening.

  Further, a distance from the bottom wall to the reflection mirror may be larger than a distance from the bottom wall to the polygon mirror.

  Since the reflection mirror and the support frame and the like can be arranged in a direction orthogonal to the rotation axis, the space can be effectively used and the size can be reduced.

  The reflection mirror may overlap with the support frame when viewed from a direction in which the light beam is incident on the reflection mirror.

  According to this, it is possible to prevent the light beam incident on the reflection mirror from passing through between the reflection mirror and the support frame and becoming stray light.

  The image forming apparatus further includes a second scanning lens through which the light beam passes after passing through the first scanning lens, and a distance from the bottom wall to the second scanning lens is a distance from the bottom wall to the first scanning lens. It may be larger than the distance.

  According to this, the size of the optical scanning device can be reduced in the direction along the rotation axis, for example, as compared with a structure in which the second scanning lens is arranged to protrude from the bottom wall toward the outside of the housing.

  The light source includes a first light source and a second light source, and the first scanning lens is provided on each of one side and the other side of the polygon mirror with the rotation axis interposed therebetween. Deflects the light beam emitted from the first light source toward the first scanning lens on the one side, and deflects the light beam emitted from the second light source toward the first scanning lens on the other side. May be.

  Further, the support frame may be made of metal.

  According to this, the rigidity of the support frame can be increased.

  According to the present invention, the size of the optical scanning device can be reduced in the direction along the rotation axis.

FIG. 1 is a perspective view showing an optical scanning device according to an embodiment of the present invention. It is the top view which looked at the optical scanning device from the axial direction. It is sectional drawing which shows an optical scanning device. It is sectional drawing which expands and shows the structure around a polygon mirror. It is the perspective view (a) which looked at the support frame from one side of the axial direction, and the perspective view (b) which looked at the other side in the axial direction. FIG. 3A is a perspective view illustrating a state in which a polygon unit is attached to a support frame, and FIG. 2B is a diagram illustrating an arrangement of holes formed in a base. FIG. 3A is an exploded perspective view illustrating a relationship between a support frame and a housing, and FIG. 3B is a cross-sectional view illustrating a structure near a protrusion.

  As shown in FIGS. 1 and 2, the optical scanning device 1 includes a housing 100, four light sources 20Y, 20M, 20C, and 20K, a polygon mirror 40, a first scanning optical system SC1, and a second scanning optical system. System SC2. The second scanning optical system SC2 is disposed on the opposite side of the first scanning optical system SC1 with respect to the rotation axis X of the polygon mirror 40. In other words, the second scanning optical system SC2 is located at a position symmetrical to the first scanning optical system SC1 with respect to a plane including the rotation axis X of the polygon mirror 40 and parallel to the main scanning direction of the first scanning optical system SC1. Are located in

  The housing 100 is made of resin and has a bottom wall 110 and four side walls 120. The bottom wall 110 is a substantially plate-like wall that is rectangular when viewed from a direction along the rotation axis X (hereinafter, also referred to as “axial direction”). Each side wall 120 protrudes in the axial direction from each of the four ends of the bottom wall 110. Here, the lid 200 is configured to have lower rigidity than the housing 100. Specifically, the thickness of the lid 200 is smaller than the thickness of the bottom wall 110 of the housing 100. The content of the inorganic filler such as glass fiber contained in the resin constituting the lid 200 is lower than that of the housing 100.

  The light sources 20Y, 20M, 20C, and 20K are devices that emit laser beams LY, LM, LC, and LK, respectively, and four photosensitive drums 251Y, 251M, 251C, and 251K that the optical scanning device 1 scans and exposes (see FIG. 3). ) Are provided.

  Light emitted from each of the light sources 20Y to 20K passes through the coupling lens 21 and the cylindrical lens 30 shown in FIG. Here, the light sources 20Y and 20M correspond to a first light source, and the light sources 20C and 20K correspond to a second light source. The laser beams LY and LM emitted from the light sources 20Y and 20M, which are the first light sources, are deflected by the polygon mirror 40 toward the first scanning optical system SC1. The laser beams LC and LK emitted from the light sources 20C and 20K, which are the second light sources, are deflected by the polygon mirror 40 toward the second scanning optical system SC2.

  The coupling lens 21 is a lens that converts the laser light LY to LK divergently emitted from the light sources 20Y to 20K into a light beam (light beam). Four coupling lenses 21 are provided corresponding to the four light sources 20Y to 20K. In the present invention, the light beam obtained by conversion by the coupling lens 21 may be any of parallel light, convergent light, and divergent light.

  The cylindrical lens 30 refracts the laser beams LY to LK and converges them in the sub-scanning direction to form a linear shape on the mirror surface 41 of the polygon mirror 40 in the main scanning direction in order to correct the tilt of the polygon mirror 40. It is a lens for imaging. The cylindrical lens 30 is disposed between the coupling lens 21 and the polygon mirror 40.

  The polygon mirror 40 is disposed substantially at the center of the housing 100 so as to face the light sources 20Y to 20K. The polygon mirror 40 has six mirror surfaces 41 provided equidistant from the rotation axis X. As shown in FIG. 3, the polygon mirror 40 is fixed to the rotor part LT of the motor PM. The polygon mirror 40 reflects the laser beams LY to LK and deflects them in the main scanning direction by rotating the respective mirror surfaces 41 about the rotation axis X by driving the motor PM. The structure around the polygon mirror 40 will be described later in detail.

  The optical scanning device 1 further includes a lid 200 that covers the opening of the housing 100 (the opening formed by the ends of the four side walls 120). The light sources 20Y to 20K (see FIG. 1), the polygon mirror 40, and the scanning optical systems SC1 and SC2 described above are supported by the housing 100. The lid 200 is made of resin, and is located on the side opposite to the bottom wall 110 with the polygon mirror 40 and each of the scanning optical systems SC1 and SC2 interposed therebetween.

  The bottom wall 110 has four recesses 111 recessed toward the lid 200. The recess 111 has four second openings HY, HM, HC, and HK for passing the laser beams LY to LK out of the housing 100. Each of the second openings HY to HK is formed at the bottom of each recess 111.

  The first scanning optical system SC1 is an optical system that forms the laser beams LY and LM deflected by the polygon mirror 40 on the photosensitive drums 251Y and 251M, and includes a first scanning lens 50 and two second scanning lenses 60. (60Y, 60M) and a plurality of reflection mirrors 71 to 75. The second scanning optical system SC2 is an optical system that forms the laser beams LC and LK deflected by the polygon mirror 40 on the photosensitive drums 251C and 251K, and includes one first scanning lens 50 and two second scanning. A lens 60 (60C, 60K) and a plurality of reflection mirrors 71 to 75 are provided. The members constituting each of the scanning optical systems SC1 and SC2 have substantially the same functions, and will be described together below.

  The first scanning lens 50 converges the laser beams LY to LK scanned at a constant angular speed by the polygon mirror 40 on the surface of the photosensitive drum 251 and scans the laser beam LY to the surface of the photosensitive drum 251 at a constant speed in the main scanning direction. The fθ lens to be converted. The first scanning lens 50 is provided on each of one side and the other side of the polygon mirror 40 with the rotation axis X of the polygon mirror 40 interposed therebetween.

  The second scanning lens 60 is a toric lens that refracts the laser beams LY to LK and converges them in the sub-scanning direction to form an image on the surface of the photosensitive drum 251 in order to correct the tilt of the polygon mirror 40. Four second scanning lenses 60 (60Y to 60K) are provided corresponding to the four light sources 20Y to 20K.

  The second scanning lens 60 is located at a position farther from the bottom wall 110 than the first scanning lens 50. That is, the distance from the bottom wall 110 of the second scanning lens 60 is larger than that of the first scanning lens 50. More specifically, the distance (distance in the axial direction) from the flat portion FF of the bottom wall 110 overlapping the polygon mirror 40 when viewed from the axial direction (the distance in the axial direction) is the distance from the flat portion FF to the first scanning lens 50. Greater than. Further, the second scanning lenses 60M and 60C through which the laser beams LM and LC pass have a greater distance from the plane portion FF than the second scanning lenses 60Y and 60K through which the laser beams LY and LK pass.

  The reflection mirrors 71 to 75 are members that reflect the laser beams LY to LK, and are formed, for example, by depositing a material having a high reflectance such as aluminum on the surface of a glass plate.

  The reflection mirror 71 is disposed between the first scanning lens 50 and the second scanning lenses 60Y and 60K, and reflects the laser beams LM and LC passing through the first scanning lens 50 toward the reflection mirror 72. The reflection mirror 72 is disposed at substantially the same position as the second scanning lenses 60M and 60C in the axial direction, and directs the laser beams LM and LC reflected by the reflection mirror 71 to the second scanning lenses 60M and 60C. To reflect.

  The reflection mirror 73 is disposed at substantially the same position as the second scanning lenses 60M and 60C in the axial direction, and directs the laser beams LM and LC passing through the second scanning lenses 60M and 60C toward the second openings HM and HC. To reflect. The distance from the plane part FF to the reflection mirror 73 is larger than the distance from the plane part FF to the polygon mirror 40. When viewed from the direction in which the laser beams LM and LC are incident on the reflection mirror 73, the reflection mirror 73 overlaps a support frame 300 described later.

  The reflection mirror 74 is disposed between the reflection mirror 71 and the side wall 120 of the housing 100 in the traveling direction of the laser beams LY and LK deflected by the polygon mirror 40, and the laser beam that has passed through the first scanning lens 50. LY and LK are reflected toward the second scanning lenses 60Y and 60K. The reflection mirror 75 is disposed at substantially the same position as the reflection mirror 72 in the axial direction, and reflects the laser beams LY and LK that have passed through the second scanning lenses 60Y and 60K toward the second openings HY and HK.

  With the above configuration, the laser beams LM and LC deflected by the polygon mirror 40 pass through the first scanning lens 50, are reflected by the reflection mirrors 71 and 72, pass through the second scanning lens 60, and then are reflected. The light is reflected by the mirror 73 to scan and expose the surface of the photosensitive drum 251. The laser beams LY and LK deflected by the polygon mirror 40 pass through the first scanning lens 50, are reflected by the reflection mirror 74, pass through the second scanning lens 60, are reflected by the reflection mirror 75, and are exposed to light. The surface of the drum 251 is scanned and exposed.

  As shown in FIG. 4, the optical scanning device 1 includes a support frame 300 made of a metal containing iron as a main component. The support frame 300 is a frame that supports the polygon mirror 40 and the motor PM, and is supported by the housing 100. The support frame 300 has a base 310 and two extending portions 320. The base 310 is arranged at a position away from the bottom wall 110, and supports the motor PM at a position away from the bottom wall 110.

  The polygon mirror 40 is disposed between the bottom wall 110 and the base 310. The motor PM is disposed between the polygon mirror 40 and the base 310. The distance D1 from the plane portion FF of the bottom wall 110 to the polygon mirror 40 is smaller than the distance D2 from the base 310 to the polygon mirror 40.

  The base 310 is formed in a flat plate shape having a plane orthogonal to the rotation axis X. The extension 320 is disposed between the polygon mirror 40 and the first scanning lens 50 when viewed from the axial direction. The extension 320 extends from the base 310 toward the bottom wall 110. More specifically, when the direction in which the polygon mirror 40 and the first scanning lens 50 are arranged is the first direction, the extending portion 320 extends from each end of the base 310 in the first direction toward the bottom wall 110.

  The distance D3 from the tip of the extension 320 to the plane portion FF of the bottom wall 110 is smaller than the distance from the polygon mirror 40 to the plane portion FF of the bottom wall 110. The extension section 320 has a first opening H1 through which the laser beams LY to LK deflected by the polygon mirror 40 pass.

  As shown in FIGS. 5A and 5B, the base 310 and each extension 320 are formed in a rectangular plate shape that is long in the axial direction and the second direction orthogonal to the above-described first direction. The extension 320 is shorter than the base 310 in the second direction. Each end of the base 310 in the second direction protrudes from the extension 320.

  The first opening H1 is formed in the extension 320 as a rectangular hole that is long in the second direction. The first opening H1 is located at a substantially central portion of the extension 320 in the second direction. The distance from the first opening H1 to the distal end of the extension 320 is smaller than the distance from the first opening H1 to the base 310.

  The base 310 has four recesses 311, a positioning hole H3, four motor fastening holes H4, and three housing fastening holes H51, H52, H53. The recess 311 is a recess that is recessed in the direction in which the extension 320 projects. The concave portion 311 is circular when viewed from the axial direction. A motor fastening hole H4 is formed at the bottom of each recess 311.

  The positioning hole H3 is a hole for positioning the motor PM in the first direction and the second direction with respect to the support frame 300. The positioning hole H3 is located substantially at the center of the base 310 in the first direction and the second direction. The bearing PM1 of the motor PM is fitted into the positioning hole H3 (see FIG. 7A).

  The four motor fastening holes H4 are holes for fastening the board BB (see FIG. 6A) of the motor PM to the base 310. The substrate BB supports a bearing PM1 that rotatably supports the rotor unit LT, and a coil that generates a magnetic field and rotates the rotor unit LT. The substrate BB is made of a metal containing iron as a main component, and has a smaller thickness than the support frame 300. Each motor fastening hole H4 is disposed at a position corresponding to the vertex of a square F1 (see FIG. 6B) surrounding the positioning hole H3 when viewed from the axial direction. Specifically, two of the four motor fastening holes H4 are arranged on one side in the second direction with respect to the positioning hole H3, and the remaining two motor fastening holes H4 are arranged in the second direction with respect to the positioning hole H3. It is located on the other side. Each motor fastening hole H4 on one side in the second direction is closer to the positioning hole H3 than each motor fastening hole H4 on the other side in the second direction.

  The three housing fastening holes H51 to H53 are holes for fastening the support frame 300 to the housing 100. Two of the three housing fastening holes H51 and H52 are round holes, and the other one of the housing fastening holes H53 is a long hole elongated in the second direction. Each of the housing fastening holes H51 to H53 is disposed at a position corresponding to the vertex of a triangle F2 (see FIG. 6B) surrounding the positioning hole H3 when viewed from the axial direction. Specifically, one of the three housing fastening holes H51 is disposed on one side in the second direction with respect to the positioning hole H3, and the remaining two housing fastening holes H52 and H53 are positioned with respect to the positioning hole H3. It is arranged on the other side in the second direction. The housing fastening hole H51 on one side in the second direction is closer to the positioning hole H3 than the housing fastening holes H52 and H53 on the other side in the second direction. The housing fastening hole H51 on one side in the second direction is located at substantially the same position as the positioning hole H3 in the first direction. The two housing fastening holes H52 and H53 on the other side in the second direction are respectively located on one side and the other side of the positioning hole H3 in the first direction.

  As shown in FIGS. 7A and 7B, the housing 100 has three protruding portions 130 protruding from the bottom wall 110 toward the base 310 of the support frame 300. Each protruding portion 130 is a boss that supports the base 310 of the support frame 300, and is disposed at a position corresponding to the three housing fastening holes H51 to H53. The projecting distance (height) of each projecting portion 130 is larger than the distance from the bottom wall 110 to the polygon mirror 40. Of the protrusions 130, the protrusion 130 corresponding to the housing fastening holes H <b> 51 and H <b> 53 has a base 131 and a protrusion 132. The protruding portion 130 corresponding to the housing fastening hole H52 has only the base portion 131.

  The base 131 has a cylindrical shape and is formed integrally with the bottom wall 110. The protrusion 132 has a cylindrical shape with a smaller diameter than the base 131, and protrudes from the tip of the base 131. The height of the projection 132 is smaller than the thickness of the base 310. The protrusion 132 of each protrusion 130 can be engaged with the housing fastening holes H51 and H53. Thereby, the position in the rotational direction is defined by the housing fastening hole H53 with respect to the housing fastening hole H51, and the base 310 is positioned with respect to the bottom wall 110. The difference in thermal expansion between the bottom wall 110 and the base 310 and the manufacturing tolerance are absorbed by the fact that the housing fastening hole H53 is a long hole and the housing fastening hole H52 does not engage with the projection 132. You.

Next, a method of attaching the polygon unit 40 having the polygon mirror 40, the motor PM, and the substrate BB to the housing 100 will be described.
First, the substrate BB is placed on the bottom wall of each recess 311 of the support frame 300 while the bearing PM1 (see FIG. 7A) of the motor PM is inserted into the positioning hole H3 of the support frame 300 shown in FIG. . Then, as shown in FIG. 6A, the screw N1 is passed through a hole (not shown) formed in the substrate BB, and the screw N1 is inserted into each motor fastening hole H4 formed in the bottom wall of each recess 311 (see FIG. 5). To conclude. Thereby, as shown in FIG. 6B, the motor PM is fastened to the base 310 at a position corresponding to the apex of the quadrangle F1 surrounding the rotation axis X when viewed from the axial direction, and the polygon unit PU is fixed to the support frame. Fixed to 300.

  After that, as shown in FIG. 7A, the projecting portions 132 of the projecting portions 130 are passed through the casing fastening holes H51 to H53 of the supporting frame 300, and the tip of the base portion 131 of the projecting portions 130 is attached to the support frame 300. The base 310 is placed. Next, as shown in FIG. 7B, the screw N2 is fastened to the protrusion 130 while passing the screw N2 through each of the housing fastening holes H51 to H53 of the support frame 300. Thereby, the base 310 is sandwiched between the head of the screw N2 and the base 131, and the support frame 300 is firmly fixed to the housing 100. At this time, as shown in FIG. 6B, the base 310 is fastened to the housing 100 at a position corresponding to the vertex of the triangle F2 surrounding the rotation axis X when viewed from the axial direction.

According to the above, the following effects can be obtained in the present embodiment.
By arranging the polygon mirror 40 near the bottom wall 110 of the housing 100, the optical axes of the laser beams LY to LK deflected by the polygon mirror 40 can be made closer to the bottom wall 110. Can be arranged at a position close to the bottom wall 110, and the optical scanning device 1 can be downsized in the axial direction.

  When the base 310 is fastened to the housing 100 at a position corresponding to the vertex of the triangle F2 surrounding the rotation axis X when viewed from the axial direction, the base 310 can be firmly fixed to the housing 100. The vibration of the polygon mirror 40 can be suppressed.

  The motor PM can be firmly fixed to the base 310 by fastening the motor PM to the base 310 at a position corresponding to the apex of the square F1 surrounding the rotation axis X when viewed from the axial direction. The vibration of the mirror 40 can be suppressed.

  Since the extension portion 320 is provided on the base portion 310, the rigidity of the base portion 310 can be increased by the extension portion 320.

  The stray light of the laser beams LY to LK can be blocked by the extension portion 320 while the laser beams LY to LK deflected by the polygon mirror 40 pass through the first opening H1 formed in the extension portion 320.

  The distance from the flat portion FF of the bottom wall 110 of each of the reflecting mirrors 73 and 75 that reflects the laser beams LY to LK toward the second openings HY to HK is larger than the distance from the flat portion FF of the polygon mirror 40. Thereby, the space on the opposite side of the plane portion FF with the polygon mirror 40 interposed therebetween in the direction along the rotation axis X can be effectively used, and downsizing in the direction along the rotation axis X can be achieved.

  When viewed from the direction in which the laser beams LY to LK are incident on the reflection mirror 73, the reflection mirror 73 overlaps the support frame 300, so that the laser beams LY to LK incident on the reflection mirror 73 are supported by the reflection mirror 73. It is possible to prevent the light from coming out from between the frames 300 and becoming stray light. In particular, in the optical scanning device 1 including the two scanning optical systems SC1 and SC2, a part of the laser light traveling on the optical path of one scanning optical system (for example, SC1) is used for the other scanning optical system (SC1). For example, it is possible to suppress a situation in which the scan optical system goes through SC2) and adversely affects the other scanning optical system.

  Since the distance of the bottom wall 110 of the second scanning lens 60 from the plane portion FF is larger than the distance of the bottom wall 110 of the first scanning lens 50 from the plane portion FF, for example, the second scanning lens is moved from the bottom wall to the housing. The optical scanning device 1 can be reduced in size in the axial direction as compared with a structure in which the optical scanning device 1 is arranged so as to protrude outside the body.

  Since the support frame 300 is made of metal, the rigidity of the support frame 300 can be increased.

  Note that the present invention is not limited to the above embodiment, but can be used in various forms as exemplified below. In the following description, members having substantially the same structure as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  In the embodiment, the first opening H1 is formed in the extension 320, but the present invention is not limited to this, and the first opening may not be formed in the extension. In this case, the distal end of the extension may be located farther from the bottom wall than the polygon mirror. Even in this case, since the laser light reflected in an unintended direction by the polygon mirror 40 can be absorbed by the tip side portion of the extension portion 320, stray light in the housing can be suppressed. it can.

  In the above embodiment, the extension portion 320 is provided, but the present invention is not limited to this, and the extension portion may not be provided.

  In the above-described embodiment, the polygon drawn by the line connecting the fastening points between the base 310 and the housing 100 is the triangle F2. However, the present invention is not limited to this and may be another polygon. . Similarly, a polygon drawn by a line connecting the fastening points between the motor PM and the base 310 may be a polygon other than the square F1.

  In the above embodiment, the support frame 300 is formed of metal, but the present invention is not limited to this. For example, the support frame may be formed of resin.

  In the above embodiment, the present invention is applied to the optical scanning device 1 including the two scanning optical systems SC1 and SC2. However, the present invention is not limited to this, and for example, the optical scanning device including only one scanning optical system. The present invention may be applied to

  In the above embodiment, the number of mirror surfaces of the polygon mirror 40 is six, but the present invention is not limited to this, and the number of mirror surfaces may be any number, for example, four.

  The components described in the embodiment and the modified examples described above may be implemented in any combination.

Reference Signs List 1 optical scanning device 20Y to 20K light source 40 polygon mirror 50 first scanning lens 100 housing 110 bottom wall 120 side wall 200 lid 300 support frame 310 base D1 distance D2 distance LY to LK laser light PM motor X rotation axis

Claims (12)

Light source,
A polygon mirror for deflecting a light beam emitted from the light source,
A motor for rotating the polygon mirror about a rotation axis,
A first scanning lens through which the light beam deflected by the polygon mirror passes;
A housing having a bottom wall and side walls and supporting the first scanning lens;
A lid located on the side opposite to the bottom wall with the first scanning lens interposed therebetween,
A support frame that is supported by the housing and has a base that supports the motor at a position away from the bottom wall,
The polygon mirror is disposed between the bottom wall and the base,
The optical scanning device according to claim 1, wherein a distance from the bottom wall to the polygon mirror is smaller than a distance from the base to the polygon mirror.   2. The optical scanning device according to claim 1, wherein the base is fastened to the housing at a position corresponding to a vertex of a polygon surrounding the rotation axis when viewed from a direction along the rotation axis. 3. apparatus. The housing has a protrusion projecting from the bottom wall and supporting the support frame,
3. The optical scanning device according to claim 1, wherein a distance of the protrusion from the bottom wall is greater than a distance from the bottom wall to the polygon mirror. 4.   4. The motor according to claim 1, wherein the motor is fastened to the base at a position corresponding to a vertex of a polygon surrounding the rotation axis, as viewed from a direction along the rotation axis. 5. The optical scanning device according to claim 1.   The support frame, when viewed from a direction along the rotation axis, is disposed between the polygon mirror and the first scanning lens, and has an extending portion extending from the base toward the bottom wall. The optical scanning device according to any one of claims 1 to 4, wherein   The distance from the tip of the extension to the bottom wall is smaller than the distance from the polygon mirror to the bottom wall, and the extension has a first opening through which light deflected by the polygon mirror passes. The optical scanning device according to claim 5, wherein: The bottom wall has a second opening for passing a light beam out of the housing,
The optical scanning device according to claim 1, further comprising a reflection mirror that reflects a light beam toward the second opening.   The optical scanning device according to claim 7, wherein a distance from the bottom wall to the reflection mirror is larger than a distance from the bottom wall to the polygon mirror.   The optical scanning device according to claim 8, wherein the reflection mirror overlaps the support frame when viewed from a direction in which the light beam is incident on the reflection mirror. A second scanning lens through which the light beam after passing through the first scanning lens passes;
The light according to any one of claims 1 to 9, wherein a distance from the bottom wall to the second scanning lens is greater than a distance from the bottom wall to the first scanning lens. Scanning device. The light source includes a first light source and a second light source,
The first scanning lens is provided one each on one side and the other side of the polygon mirror with the rotation axis interposed therebetween,
The polygon mirror deflects the light beam emitted from the first light source toward the first scanning lens on one side, and deflects the light beam emitted from the second light source on the first scanning lens on the other side. The optical scanning device according to any one of claims 1 to 10, wherein the light is deflected toward the optical scanning device.   The optical scanning device according to claim 1, wherein the support frame is made of metal.

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