Polygon mirror, optical polarizer, optical scanning device, and image forming apparatus

Abstract

To improve optical characteristics of a polygon mirror.SOLUTION: A polygon mirror includes a resin body having a first surface, a second surface opposite to the first surface, an inside surface crossing the first surface and the second surface so as to surround a through hole from the first surface toward the second surface, and an outside surface crossing the first surface and the second surface on a side opposite to the inside surface, wherein a first intersection between the first surface and the outside surface is defined as a first reference of a height in a direction from a second intersection between the second surface and the outside surface toward the first intersection, the first surface has at least one projection projecting to a side opposite to the second surface with respect to the first reference, the second intersection is defined as a second reference of the height in the direction, the second surface has at least one recess recessed to the side of the first surface with respect to the second reference, and the projection forms the inside surface.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a polygon mirror.

Background Art

[0002] An optical scanning device used in an image forming apparatus such as a laser printer optically modulates laser light emitted from a light source according to an image signal, and the optically modulated laser light is deflected and scanned by a light deflector having a rotating polygon mirror. The laser light scanned by the light deflector is imaged on a photosensitive drum, which is an example of an image carrier, by a scanning lens such as an fθ lens. Thereby, an electrostatic latent image is formed on the surface of the photosensitive drum.

[0003] Various devices have been made for the polygon mirror used in this type of apparatus to suppress deterioration of optical characteristics due to deformation of the reflecting surface.

[0004] Patent Document 1 proposes a form in which heat radiating protrusions are provided above and below the polygon mirror.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When a force is applied to the polygon mirror due to rotation of the polygon mirror having protrusions, etc., an excessive force may be applied to the protrusions. As a result, the reflecting surface of the polygon mirror may be deformed or the polygon mirror may vibrate, deteriorating the optical characteristics of the polygon mirror.

[0007] Therefore, an object of the present invention is to provide a technique advantageous in improving the optical characteristics of a polygon mirror.

Means for Solving the Problem

[0008] The means for solving the above problem includes a resin body including a first surface, a second surface facing the first surface, an inner surface intersecting the first surface and the second surface so as to surround a through hole extending from the first surface to the second surface, and an outer surface intersecting the first surface and the second surface on the side opposite to the inner surface. The first intersection line between the first surface and the outer surface is used as a first reference for the height in the direction from the second intersection line between the second surface and the outer surface to the first intersection line. The first surface protrudes on the side opposite to the side of the second surface with respect to the first reference, and has a protrusion. The second intersection line is used as a second reference for the height in the above direction. The second surface has a recess that sinks on the side of the first surface with respect to the second reference. The protrusion is characterized by forming the inner surface. plural The means for solving the above problem includes a resin body including a first surface, a second surface facing the first surface, an inner surface intersecting the first surface and the second surface so as to surround a through hole extending from the first surface to the second surface, and an outer surface intersecting the first surface and the second surface on the side opposite to the inner surface. The first intersection line between the first surface and the outer surface is used as a first reference for the height in the direction from the second intersection line between the second surface and the outer surface to the first intersection line. The first surface protrudes on the side opposite to the side of the second surface with respect to the first reference, and has a protrusion. The second intersection line is used as a second reference for the height in the above direction. The second surface has a recess that sinks on the side of the first surface with respect to the second reference. The protrusion is characterized by forming the inner surface. plural The means for solving the above problem includes a resin body including a first surface, a second surface facing the first surface, an inner surface intersecting the first surface and the second surface so as to surround a through hole extending from the first surface to the second surface, and an outer surface intersecting the first surface and the second surface on the side opposite to the inner surface. The first intersection line between the first surface and the outer surface is used as a first reference for the height in the direction from the second intersection line between the second surface and the outer surface to the first intersection line. The first surface protrudes on the side opposite to the side of the second surface with respect to the first reference, and has a protrusion. The second intersection line is used as a second reference for the height in the above direction. The second surface has a recess that sinks on the side of the first surface with respect to the second reference. The protrusion is characterized by forming the inner surface.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide an advantageous technique for improving the optical characteristics of a polygon mirror.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the embodiments described below are merely one embodiment of the invention and are not limited thereto. And, common configurations will be described with reference to a plurality of drawings, and the description of the configurations with common reference numerals will be omitted as appropriate. For different matters with the same name, they can be distinguished by adding "first" or "second" and so on.

[0012] <First Embodiment> FIG. 1 is a schematic cross-sectional view showing an image forming apparatus 100 according to the first embodiment. The image forming apparatus 100 is an electrophotographic type. The image forming apparatus 100 in FIG. 1 is a printer, but is not limited thereto, and may be a copier, a facsimile machine, a multifunction machine, or the like.

[0013] The image forming apparatus 100 includes an image forming unit 110 that forms an image on a sheet P which is a recording material. The image forming unit 110 includes a laser scanning device 101, a process cartridge 102, a transfer roller 107 which is an example of a transfer unit, and a fixing device 108. The process cartridge 102 includes a photosensitive drum 103 which is an example of an image carrier, a charging unit 111, and a developing unit 112.

[0014] The laser scanning device 101 emits a laser beam L based on the obtained image information and irradiates the photosensitive drum 103 of the process cartridge 102, thereby scanning the surface of the photosensitive drum 103 with the laser beam L. As a result, a latent image is formed on the photosensitive drum 103, and this latent image is visualized as a toner image by toner which is a developer by the process cartridge 102.

[0015] On the other hand, the sheet P loaded on the sheet loading plate 104 is fed one by one while being separated by the feeding roller 105 and is conveyed to the nip portion between the photosensitive drum 103 and the transfer roller 107 by the conveying roller 106. The toner image formed on the photosensitive drum 103 is transferred onto the sheet P conveyed to the nip portion by the transfer roller 107.

[0016] The sheet P onto which the unfixed toner image is transferred is further conveyed to the fixing device 108 on the downstream side. The fixing device 108 has a heating element inside, and fixes the toner image as an image on the sheet P by heating and pressing the sheet P. Thereafter, the sheet P is discharged outside the machine by the discharging roller 109.

[0017] FIG. 2(a) is a perspective view schematically showing the laser scanning device 101 according to the first embodiment. The laser scanning device 101 includes a housing 203, and a light source 201, a cylindrical lens 202, an fθ lens 205, and a scanner motor 1 which is an example of a light deflector, supported by the housing 203. An optical aperture 204 is formed in the housing 203. The laser beam L emitted from the light source 201 is condensed by the cylindrical lens 202 and limited to a predetermined beam diameter by the optical aperture 204.

[0018] The laser beam L that has passed through the optical aperture 204 is deflected by the scanner motor 1, and after passing through the fθ lens 205, it is focused on the photosensitive drum 103 in FIG. 1 to form an electrostatic latent image.

[0019] The light source 201, the cylindrical lens 202, the scanner motor 1, etc. are housed in the housing 203. The opening of the housing 203 is closed by an optical lid (not shown) made of resin or metal.

[0020] FIG. 2(b) is a cross-sectional view of the scanner motor 1 according to the first embodiment. FIG. 2(b) schematically shows a cross-section of the scanner motor 1 cut along a plane including the rotation center. The scanner motor 1 includes a substrate 4 made of sheet metal, a bearing sleeve 5 fixed to the substrate 4, a rotor 7 having a rotor magnet 6, and a rotary shaft 8 that is rotatably supported by the bearing sleeve 5 and is integral with the rotor 7. Further, the scanner motor 1 includes a pedestal 2 integral with the rotor 7, a stator coil 9 fixed to the substrate 4, a polygon mirror 3 fixed to the rotary shaft 8 via the pedestal 2, and a spring 39 that presses the polygon mirror 3 against the motor pedestal 2 with an appropriate force to prevent the pedestal from idling. The rotor 7 and the stator coil 9 constitute a motor 10, which is an example of a drive source for rotationally driving the polygon mirror 3. The polygon mirror 3 deflects the laser beam L shown in FIG. 2(a) by rotating. The polygon mirror 3 has a resin body 30 that is a substrate formed of resin, and a reflection film 31 formed on each side surface of the resin body 30.

[0021] <Second Embodiment> Next, the polygon mirror 3 according to the second embodiment will be described. In the second embodiment, descriptions of the same configurations as those in the first embodiment will be omitted.

[0022] FIGS. 3(a) and 3(b) are perspective views of the resin body 30 in the polygon mirror 3 according to the present embodiment. FIG. 3(a) is a top perspective view of the resin body 30 in the polygon mirror 3, and FIG. 3(b) is a bottom perspective view of the resin body 30 in the polygon mirror 3.

[0023] The resin body 30 is prismatic, and in this embodiment, it is a quadrangular prism-shaped resin body. It is preferable to use a thermoplastic resin as the resin material of the resin body 30. Among thermoplastic resins, it is preferable to use a cycloolefin polymer, a cycloolefin copolymer, a polycarbonate, or an acrylic.

[0024] The resin body 30 has a top surface 301 which is the first surface, and a bottom surface 302 which is the second surface opposite to the first surface. Further, it has an inner surface 330 that intersects with the first and second surfaces, and a plurality of, in this embodiment, four outer surfaces 351, 352, 353, 354 that intersect with the first and second surfaces on the side opposite to the inner surface 330. A through hole 16 is formed at a position including a virtual line C0 that passes through the intersection line of the two diagonal lines L11 and L12 of the top surface 301 and the intersection line of the two diagonal lines L21 and L22 of the bottom surface 302. The inner surface 330 is formed so as to surround the through hole 16. That is, the virtual line C0 is the rotation center line of the resin body 30 and the central axis of the through hole 16. A rotating shaft 8 shown in FIG. 2(b) is inserted into the through hole 16. In this embodiment, the through hole 16 is circular, but it does not necessarily have to be circular.

[0025] FIG. 4(a) is a first cross-sectional view of the resin body 30 according to this embodiment. FIG. 4(a) shows the first cross-section of the resin body 30 along the line IV-IV in FIG. 3(a). FIG. 4(b) is an enlarged view of the main part of the resin body 30 shown in FIG. 4(a).

[0026] FIG. 5 is a second cross-sectional view of the resin body 30 according to this embodiment. FIG. 5 shows the second cross-section of the resin body 30 along the line V-V in FIG. 3(a).

[0027] Set the first intersection line 310 between the first surface and the outer surfaces 351 to 354 as the first height reference in the direction from the second intersection line 320 between the second surface and the outer surfaces 351 to 354 to the first intersection line 310 between the first surface and the outer surfaces 351 to 354. The top surface 301 has at least one protrusion protruding with respect to the first reference on the side opposite to the side of the bottom surface 302. The protrusions are arranged on the diagonal lines L11 and L12 of the top surface 301 and form the inner surface 330. In this embodiment, four protrusions 311, 312, 313, and 314 are formed at positions on the diagonal lines L11 and L12 and forming the inner surface 330, but at least one protrusion may be provided. By the protrusions 311 to 314 forming the inner surface 330, the force applied by the rotation of the polygon mirror 3 or the like can be reduced. It is more preferable that the number of protrusions provided is the same as the number of outer surfaces or an integral multiple.

[0028] The configuration of the protrusions 311 to 314 will be described with reference to FIG. 4(b). The protrusion 311 has a side surface 3112 in a direction perpendicular to the virtual line C0 and a side surface 3113 in the rotation direction of the resin body 30. The side surface in the direction perpendicular to the virtual line C0 refers to the surface on the outer surface side among the side surfaces in the direction perpendicular to the virtual line C0. The side surface 3112 in the direction perpendicular to the virtual line C0 is inclined with respect to the virtual line C0 which is the rotation axis of the resin body 30.

[0029] Here, the direction perpendicular to the virtual line C0 is the same as the radial direction of the through hole 16, and the rotation direction of the resin body 30 is the same as the circumferential direction of the through hole 16.

[0030] The side surface 3123 in the rotation direction of the resin body 30 has an inclined portion 3124 inclined with respect to the virtual line C0 on the root side of the protrusion 312. Similarly, with respect to the protrusions 311, 313, and 314, the side surfaces in the direction perpendicular to the virtual line C0 and the side surfaces in the rotation direction of the resin body 30 have surfaces 3112, 3132, 3142 inclined with respect to the virtual line C0 and side surfaces 3113, 3133, 3143 in the rotation direction of the resin body 30, respectively. Also, the inclined portions 3114, 3134, and 3144 are inclined with respect to the virtual line C0 which is the rotation axis of the resin body 30 in the same manner as the inclined portion 3124.

[0031] Since the side surfaces in the rotational direction of the resin body 30 of the protrusions 311 to 314 have inclined surfaces 3114 to 3144, the wind pressure due to the rotation of the resin body 30 can be deflected. Thereby, it is possible to suppress the deterioration of the optical characteristics due to the vibration of the polygon mirror 3. Also, it is possible to suppress the wind noise due to the rotation of the polygon mirror 3.

[0032] Since the side surfaces 3112 to 3142 in the direction perpendicular to the virtual line C0 of the protrusions 311 to 314 are inclined surfaces, even when an excessive force acts on the protrusions 311 to 314 due to the rotation of the polygon mirror 3 or the like, the protrusions 311 to 314 can suppress the deformation of the polygon mirror 3 and suppress the deterioration of the optical characteristics of the polygon mirror 3.

[0033] Also, since the virtual line C0 is the rotation center axis, by providing the protrusions 311 to 314 at positions close to the virtual line C0, it is in a form in which it is difficult for an excessive force to act on the protrusions 311 to 314. Here, the protrusions 311 to 314 forming the inner surface 330 do not necessarily have to be continuous with the inner surface existing in the height range from the first reference to the second reference. If the distance from the inner surface existing in the height range from the first reference to the second reference to the protrusions 311 to 314 is within the height H1 of the protrusions 311 to 314 in the direction perpendicular to the virtual line C0, it is considered that the protrusions 311 to 314 form the inner surface 330.

[0034] In the present embodiment, the protrusions 311 to 314 disposed on the top surface 301 have surfaces inclined with respect to the virtual line C0 on both the side surface in the direction perpendicular to the virtual line C0 and the side surface in the rotational direction of the resin body 30. However, it is sufficient that at least one of the side surfaces 3112 to 3142 in the direction perpendicular to the virtual line C0 of the protrusions 311 to 314 or the side surfaces 3113 to 3143 in the rotational direction of the resin body 30 is a surface inclined with respect to the virtual line C0.

[0035] The top surface 301 has holes 181 to 184 whose outer surfaces 351 to 354 are recessed with respect to the first reference on the side of the bottom surface 302 and whose phases around the virtual line C0 match. The holes 181 to 184 are four holes in this embodiment, but at least one hole may be provided.

[0036] The bottom surface 302 uses the second intersection line 320 as the second reference for the height in the direction from the second intersection line 320 of the second surface and the outer surface to the first intersection line 310 of the first surface and the outer surface, and has recessed portions 321, 322, 323, 324 arranged on the diagonal lines L21, L22 that are recessed with respect to the second reference on the side of the top surface 301. The recessed portions 321 to 324 are four recessed portions in this embodiment, but at least one recessed portion may be provided, and it is preferable that they are provided in the same number and in the same phase as the protruding portions provided on the top surface 301. The recessed portions 321 to 324 only need to overlap at least partially with the protruding portions 311 to 314 in the direction from the first intersection line 310 to the second intersection line 320. Further, the recessed portions 321 to 324 have side surfaces 3212, 3222, 3232, 3242 that are side surfaces in the direction perpendicular to the virtual line C0, and the side surfaces 3212 to 3242 that are side surfaces in the direction perpendicular to the virtual line C0 may have inclined portions inclined with respect to the virtual line C0. Similarly, the recessed portions 321 to 324 have side surfaces 3213, 3223, 3233, 3243 that are side surfaces in the rotation direction of the resin body 30, and the side surfaces 3213 to 3243 that are side surfaces in the rotation direction of the resin body 30 may have inclined portions inclined with respect to the virtual line C0. By using this configuration, when stacking a plurality of resin bodies 30, the fitting between the protruding portion on the top surface of one resin body and the recessed portion on the bottom surface of another resin body becomes easy. The bottom surface 302 has side surfaces 3222 to 3242 in the direction perpendicular to the virtual line C0 of the recessed portions 322 to 324 that have the same function as the side surface 3212 in the direction perpendicular to the virtual line C0 of the recessed portion 321.

[0037] By providing the protruding portions 311 to 314 that form the inner surface 330 on the first surface and the recessed portions 321 to 324 on the second surface, it is possible to disperse force compared to a flat polygon mirror, and a polygon mirror with high strength can be formed.

[0038] The height H1 of the protrusions 311 to 314 on the first surface is greater than the depth D1 of the recesses 321 to 324 on the second surface. Thereby, when the resin bodies 30 are stacked, a certain gap is formed between the top surface 301 of the lower resin body 30 and the bottom surface 302 of the upper resin body 30, and the resin bodies 30 can be arranged at equal intervals. Further, the height S1 of the inclined portions 3114 to 3144 on the side surfaces in the rotation direction of the resin body 30 of the protrusions 311 to 314 is the same as or smaller than the difference between the height H1 of the protrusions 311 to 314 and the depth D1 of the recesses 321 to 324 (H1 - D1 ≥ S1). Therefore, it is possible to avoid interference between the recesses 321 to 324 and the inclined portions 3114 to 3144 on the side surfaces in the rotation direction of the resin body 30 of the protrusions 311 to 314.

[0039] The height H2 of the inclined portions 3112 to 3142 on the side surfaces in the direction perpendicular to the virtual line C0 of the protrusions 311 to 314 is greater than the height S1 of the inclined portions 3114 to 3144 on the side surfaces in the rotation direction of the resin body 30 of the protrusions 311 to 314. Thereby, when the resin bodies 30 are stacked, the surfaces of the protrusions 311 to 314 of a certain resin body 30 other than the inclined portions 3114 to 3144 on the side surfaces in the rotation direction of the resin body 30 become mating surfaces with the side surfaces in the rotation direction of the resin bodies 30 of the recesses 321 to 324 provided on the second surface of another resin body 30, and the plurality of resin bodies 30 can rotate in conjunction with each other in the rotation direction of the resin body 30. In the present embodiment, the magnitudes of H1 and H2 are equal.

[0040] In the present embodiment, the height H1 is, for example, 0.5 mm, and the depth D1 is, for example, 0.3 mm. The height H1 of the protrusions 311 to 314 may be 0.4 mm to 0.7 mm, and the depth D1 of the recesses 321 to 324 may be 0.1 mm to 0.35 mm. Further, the height S1 of the inclined portions 3114 to 3144 of the side surfaces 3113 to 3143 in the rotation direction of the resin body 30 of the protrusions 311 to 314 is, for example, 0.2 mm, but it may be greater than 0 mm and 0.35 mm or less.

[0041] The width W1 in the rotational direction of the resin body 30 of the protrusions 311 to 314 is smaller than the width W2 in the rotational direction of the resin body 30 of the recesses 321 to 324. The width B1 in the direction perpendicular to the virtual line C0 of the protrusions 311 to 314 is smaller than the width B2 in the direction perpendicular to the virtual line C0 of the recesses 321 to 324.

[0042] The width W1 in the rotational direction of the resin body 30 of the protrusions 311 to 314 is, for example, 0.15 mm, and the width W2 in the rotational direction of the resin body 30 of the recesses 321 to 324 is, for example, 0.17 mm. Since W1 is smaller than W2, the protrusions 311 to 314 can be smoothly inserted into the recesses 321 to 324. Also, the width B1 in the direction perpendicular to the virtual line C0 of the protrusions 311 to 314 is, for example, 0.20 mm. The width B2 in the direction perpendicular to the virtual line C0 of the recesses 321 to 324 is, for example, 0.35 mm. Since B1 is smaller than B2, the protrusions 311 to 314 can be smoothly inserted into the recesses 321 to 324. The width W1 in the rotational direction of the resin body 30 of the protrusions 311 to 314 is 0.05 mm to 0.25 mm, and the rotational direction width W2 of the resin body 30 is 0.07 mm to 0.27 mm. Also, the width B1 in the direction perpendicular to the virtual line C0 of the recesses 321 to 324 is 0.10 mm to 0.30 mm, and the width B2 in the rotational direction of the resin body 30 of the recesses 321 to 324 is 0.25 mm to 0.45 mm.

[0043] Next, the mold used to manufacture the resin body 30 will be described. FIG. 6 is a schematic cross-sectional view of the mold 140 according to the present embodiment. FIG. 6 shows the mold 140 in a clamped state. The mold 140 has a cavity 50 for forming the resin body 30. When the mold 140 is clamped, the cavity 50 is defined.

[0044] FIGS. 7(a) and 7(b) are perspective views of the cavity 50 in the mold according to the first embodiment. FIG. 7(a) is a top perspective view of the cavity 50, and FIG. 7(b) is a bottom perspective view of the cavity 50.

[0045] The cavity 50 is a prismatic-shaped, in this embodiment, a quadrangular prism-shaped space. The mold 140 has a top surface forming surface 501 that transfers the top surface 301 of the resin body 30, and a bottom surface forming surface 502 that transfers the bottom surface 302 of the resin body 30. Further, the mold 140 has a plurality, in this embodiment, four side surface forming surfaces 551, 552, 553, 554 that transfer the plurality of outer side surfaces 351 to 354 of the resin body 30. The cavity 50 is defined by these plurality of surfaces 501, 502, 551 to 554.

[0046] The mold 140 has a runner stripper plate 141, a fixed side mold plate 142, and a movable side mold plate 143. The runner 580 is defined by the runner stripper plate 141 and the fixed side mold plate 142.

[0047] The fixed side mold plate 142 includes the above-described top surface forming surface 501, a plurality of gates 571, 572, 573, 574 for injecting molten resin into the cavity 50, a mold hole 1421, and an angular pin 1422. The mold hole 1421 is provided coaxially with the through hole 16. That is, the center line of the mold hole 1421 is the virtual line C0. In this embodiment, the number of gates is preferably four, which is the same as the number of side surface forming surfaces 551 to 554. Thereby, in the injection process described later, the symmetry of the pressure distribution of the resin body 30 is increased, and the shape accuracy of the outer side surfaces 351 to 354 serving as the light reflection surfaces is increased.

[0048] Further, it is preferable that the gates 571 to 574 and the side surface forming surfaces 551 to 554 have the same phase around the virtual line C0 which is the central axis of the mold hole 1421. Thereby, in the injection process, the symmetry of the pressure distribution of the resin body 30 is further increased, and the shape accuracy of the outer side surfaces 351 to 354 serving as the light reflection surfaces is further improved. Also, the welds generated between the gates 571 to 574 can be induced to the ends of the outer side surfaces 351 to 354 which are outside the scanning range of the laser beam L in Fig. 2(a).

[0049] The movable-side mold plate 143 has a movable-side core 1431, a slide core 144, and an ejector plate 145. The movable-side core 1431 includes the above-described bottom surface forming surface 502 and a mold shaft 1432. The slide core 144 includes side surface forming surfaces 551 to 554, and slides in a direction orthogonal to the virtual line C0 guided by the angular pin 1422 as the movable-side mold plate 143 opens and closes. The mold shaft 1432 is for forming the through hole 16.

[0050] The ejector plate 145 preferably has four ejector pins, the same number as the side surface forming surfaces 551 to 554. Thereby, when the ejector pin 1451 is projected in the step of releasing the resin body 30 from the mold 140, the force can be evenly transmitted to the resin body 30, and the deformation of the resin body 30 due to the release can be suppressed.

[0051] Since the top surface forming surface 501 is a quadrilateral, there are two diagonal lines L51 and L52. Similarly, since the bottom surface forming surface 502 is a quadrilateral, there are two diagonal lines L61 and L62.

[0052] The top surface forming surface 501 has recessed portions 511, 512, 513, and 514 disposed on the diagonal lines L51 and L52 that are recessed with respect to the top surface forming surface 501. The recessed portions 511 to 514 disposed on the diagonal lines L51 and L52 are four recessed portions in the present embodiment, but at least one recessed portion may be provided.

[0053] The recessed portion 511 has a side surface 5112 in a direction perpendicular to the virtual line C0 of the recessed portion 511 and a side surface 5113 in the rotational direction of the resin body 30 of the recessed portion 511. The side surface 5112 in a direction perpendicular to the virtual line C0 is inclined with respect to the virtual line C0. The side surface 5113 in the rotational direction of the resin body 30 has an inclined portion 5114 that is inclined with respect to the virtual line C0 on the root side of the recessed portion 511.

[0054] The top surface forming surface 501 has protrusions 581, 582, 583, 584 that protrude with respect to the top surface forming surface 501 and whose phases around the virtual line C0 match those of the side surface forming surfaces 551 to 554. In this embodiment, there are four protrusions as the at least one hole whose phase around the virtual line C0 matches those of the side surface forming surfaces 551 to 554, but at least one protrusion may be provided.

[0055] The bottom surface forming surface 502 has convex portions 521, 522, 523, 524 that protrude with respect to the bottom surface forming surface 502 and are arranged on the diagonals L61, L62. In this embodiment, there are four convex portions as the convex portions 581 to 584 arranged on the diagonals L61, L62, but at least one convex portion may be provided.

[0056] Similar to the resin body 30, the depth of the recessed portions 511 to 514 is greater than the height of the convex portions 521 to 524. The inclined portions 5114 to 5144 of the side surfaces 5112 to 5142 in the direction perpendicular to the virtual line C0 of the recessed portions 511 to 514 and the side surfaces 5113 to 5143 in the rotational direction of the resin body 30 of the recessed portions 511 to 514 are inclined with respect to the virtual line C0. The depth of the side surfaces 5112 to 5142 in the direction perpendicular to the virtual line C0 of the recessed portions 511 to 514 is greater than the depth of the inclined portions 5114 to 5144 of the side surfaces 5113 to 5143 in the rotational direction of the resin body 30 of the recessed portions 511 to 514. The depth of the inclined portions 5114 to 5144 of the side surfaces 5113 to 5143 in the rotational direction of the resin body 30 of the recessed portions 511 to 514 is the same as or smaller than the difference between the depth of the recessed portions 511 to 514 and the height of the convex portions 521 to 524. The width of the recessed portions 511 to 514 in the rotational direction of the resin body 30 is smaller than the width of the convex portions 521 to 524 in the rotational direction of the resin body 30. The width of the recessed portions 511 to 514 in the direction perpendicular to the virtual line C0 is smaller than the width of the convex portions 521 to 524 in the direction perpendicular to the virtual line C0.

[0057] Next, a method for manufacturing the polygon mirror 3 will be described. FIGS. 8(a) to 8(c) and FIGS. 9(a) to 9(c) are explanatory diagrams showing each step of the method for manufacturing the resin body 30 in the polygon mirror 3 according to the present embodiment. FIG. 10 is an explanatory diagram showing each step of the method for manufacturing the reflection film 31 in the polygon mirror 3 according to the first embodiment. In the mold opening step shown in FIG. 8(a), the mold 140 is opened. Next, in the mold clamping step shown in FIG. 8(b), the mold 140 is clamped. At this time, the mold shaft 1432 of the movable-side mold plate 143 is fitted into the mold hole 1421 of the fixed-side mold plate 142, so that the positions of the fixed-side mold plate 142 and the movable-side mold plate 143 are aligned, and the cavity 50 is defined in the mold 140.

[0058] Next, in the injection step shown in FIG. 8(c), the molten resin M1 is injected into the cavity 50 by an injection molding machine (not shown) through the runner 580 and the gates 571 to 574 in FIG. 7(a).

[0059] Next, in the cooling step shown in FIG. 9(a), the mold 140 is set to a predetermined temperature lower than the temperature of the molten resin M1 to cool and solidify the molten resin M1 to form the resin body 30. The mold 140 is, for example, a water-cooled type and is cooled to a predetermined temperature by water.

[0060] After the resin body 30 is sufficiently cooled, the mold 140 is opened in the mold opening step shown in FIG. 9(b). At this time, the top surface forming surface 501 of the fixed-side mold plate 142 is separated from the top surface 301 of the resin body 30, and the side surface forming surfaces 551 to 554 of the slide core 144 shown in FIGS. 7(a) and 7(b) are separated from the side surfaces 351 to 354 of the resin body 30 shown in FIGS. 3(a) and 3(b). Further, the runner 32 connected to the resin body 30 is separated from the resin body 30 by the runner stripper plate 141.

[0061] Then, in the mold release process shown in FIG. 9(c), the ejector plate 145 is advanced toward the movable core 1431 to project the ejector pins 1451 from the movable core 1431, and the bottom surface 302 of the resin body 30 is separated from the bottom surface forming surface 502 of the movable core 1431. Thereby, the resin body 30 is released from the mold 140.

[0062] Thereafter, in the vapor deposition process, as shown in FIG. 10, a plurality of resin bodies 30 are stacked and inserted into the vapor deposition jig 701. By inserting the protrusions 311 to 314 of the resin body 30 shown in FIGS. 3(a) and 3(b) into the recesses 321 to 324, the outer surfaces 351 to 354 of the resin body 30 are aligned.

[0063] As described above, the height H1 of the protrusions 311 to 314 is larger than the depth D1 of the recesses 321 to 324. Therefore, when the resin bodies 30 are stacked, a certain gap is formed between the top surface 301 of the lower resin body 30 and the bottom surface 302 of the upper resin body 30, and the resin bodies 30 can be arranged at equal intervals. Also, the height S1 of the inclined portions 3114 to 3144 on the side surface in the rotational direction of the resin body 30 of the protrusions 311 to 314 is the same as or smaller than the difference between the height H1 of the protrusions 311 to 314 and the depth D1 of the recesses 321 to 324. Therefore, interference between the recesses 321 to 324 and the inclined portions 3114 to 3144 on the side surface in the rotational direction of the resin body 30 of the protrusions 311 to 314 can be avoided.

[0064] Then, by vapor-depositing a metal such as aluminum on the outer surfaces 351 to 354 of the resin body 30, the reflective films 31 shown in FIGS. 2(a) and 2(b) that serve as light reflection surfaces are formed on the outer surfaces 351 to 354. Thereby, the polygon mirror 3 is manufactured.

[0065] Here, a case will be described where the side surfaces 5112 to 5142 in the direction perpendicular to the virtual line C0 of the recessed portions 511 to 514 of the mold are not inclined with respect to the virtual line C0, and there are no inclined portions 5114 to 5144 on the side surfaces 5113 to 5143 in the rotational direction of the resin body 30 of the recessed portions 511 to 514 of the mold. That is, it is also the case of manufacturing a resin body of a comparative example in which the side surfaces 3112 to 3142 in the direction perpendicular to the virtual line C0 of the protruding portions 311 to 314 of the resin body 30 are not inclined with respect to the virtual line C0, and there are no inclined portions 3114 to 3144 on the side surfaces 3113 to 3143 in the rotational direction of the resin body 30 of the protruding portions 311 to 314 of the resin body 30. In the mold opening process, when the mold is opened and the top surface forming surface of the fixed-side mold plate is separated from the top surface of the resin body 30, a large mold release resistance occurs between the side surfaces in the direction perpendicular to the virtual line C0 of the recessed portions 511 to 514 and the side surfaces in the direction perpendicular to the virtual line C0 of the protruding portions 311 to 314. Similarly, a large mold release resistance occurs between the side surfaces in the rotational direction of the resin body 30 of the recessed portions 511 to 514 and the side surfaces in the rotational direction of the resin body 30 of the protruding portions 311 to 314. When the mold release resistance between the top surface of the resin body and the top surface forming surface of the fixed-side mold plate increases, the top surface of the resin body and the top surface forming surface of the fixed-side mold plate do not separate, and a mold release failure occurs where the resin body remains on the fixed-side mold plate.

[0066] Therefore, in the present embodiment, in order to reduce the mold release resistance between the top surface 301 of the resin body 30 and the top surface forming surface 501 of the fixed-side mold plate 142, the resin body 30 is molded using a mold in which the side surfaces 5112 to 5142 in the direction perpendicular to the virtual line C0 of the recessed portions 511 to 514 are inclined with respect to the virtual line C0. Since the side surfaces 5112 to 5142 in the direction perpendicular to the virtual line C0 of the recessed portions 511 to 514 are inclined with respect to the virtual line C0, the mold release resistance generated between the side surfaces 5112 to 5142 in the direction perpendicular to the virtual line C0 of the recessed portions 511 to 514 and the side surfaces 3112 to 3142 in the direction perpendicular to the virtual line C0 of the protruding portions 311 to 314 is reduced. As a result, the top surface 301 of the resin body 30 and the top surface forming surface 501 of the fixed-side mold plate 142 can be stably separated, and the possibility of a mold release failure in which the resin body 30 remains on the fixed-side mold plate 142 can be reduced.

[0067] Let the inclination angle between the side surfaces 5113 to 5143 in the rotational direction of the resin body 30 of the recessed portions 511 to 514 of the mold and the virtual line C0 be θ1, that is, let the inclination angle between the side surfaces 3112 to 3142 in the direction perpendicular to the virtual line C0 of the protrusions 311 to 314 and the virtual line C0 be θ1. Also, let the inclination angle between the side surfaces 5113 to 5143 in the rotational direction of the resin body 30 of the recessed portions 511 to 514 of the mold and the virtual line C0 be θ2, that is, let the inclination angle between the inclined portions 3114 to 3144 of the side surfaces 3113 to 3143 in the rotational direction of the resin body 30 of the protrusions 311 to 314 and the virtual line C0 be θ2. The inclination angles θ1 to θ2 are preferably 10 degrees or more and 60 degrees or less in view of the mold release property of the resin body 30 in the mold opening process and the rigidity of the resin body 30. The inclination angles θ1 to θ2 are, for example, 45 degrees. If θ1 and θ2 are less than 10 degrees, the top surface 301 of the resin body 30 and the top surface forming surface 501 of the fixed-side mold plate 142 do not stably separate in the mold opening process, and the possibility of mold release failure increases. Also, if the inclination angle θ1 is greater than 60 degrees, the distortion caused by the shape of the protrusions 311 to 314 increases in the cooling process, and there is concern that the shape accuracy of the outer surfaces 351 to 354 will be lost.

[0068] In addition, in order to improve the shape accuracy of the outer surfaces 351 to 354 of the resin body 30 and the bottom surface 302 in contact with the pedestal 2, the side surface forming surfaces 551 to 554 and the bottom surface forming surface 502 for forming the outer surfaces 351 to 354 and the bottom surface 302 of the resin body 30 are preferably provided on the same movable-side mold plate 143. Also, in order to prevent interference between the bottom surface 302 of the resin body 30 and the pedestal 2, it is desirable to provide recessed portions 321 to 324 recessed with respect to the bottom surface 302 on the bottom surface 302 of the resin body 30, and to provide protrusions 311 to 314 protruding with respect to the top surface 301 on the opposing top surface 301. Therefore, it is necessary to arrange the top surface forming surface 501 on the fixed-side mold plate 142 of the mold 140 and the bottom surface forming surface 502 on the movable-side mold plate 143. Thus, by making the recessed portions 511 to 514 recessed with respect to the top surface forming surface 501 of the top surface forming surface 501 in the shape of the present embodiment, the top surface 301 of the resin body 30 and the top surface forming surface 501 of the fixed-side mold plate 142 can be stably separated. As a result, the possibility of mold release failure in which the resin body 30 remains on the fixed-side mold plate 142 is reduced, and the yield of manufacturing the resin polygon mirror 3 increases.

[0069] In this embodiment, in order to reduce the release resistance between the top surface 301 of the resin body 30 and the top surface forming surface 501 of the fixed-side template, the resin body 30 is molded using a mold in which the side surfaces 5113 to 5143 in the rotation direction of the resin body 30 in the recessed portions 511 to 514 have inclined portions 5114 to 5144. Since the side surfaces 5113 to 5143 in the rotation direction of the resin body 30 in the recessed portions 511 to 514 have the inclined portions 5114 to 5144, the release resistance generated between the side surfaces 5113 to 5143 in the rotation direction of the resin body 30 in the recessed portions 511 to 514 and the side surfaces 3114 to 3144 in the rotation direction of the resin body 30 of the protruding portions 311 to 314 is reduced. As a result, the top surface 301 of the resin body 30 and the top surface forming surface 501 of the fixed-side template 142 can be stably separated, and the possibility of occurrence of a release defect in which the resin body 30 remains on the fixed-side template 142 is reduced. Thereby, the yield of manufacturing the resin polygon mirror 3 is further increased.

[0070] The length L of each side S11 to S14, S21 to S24 of the resin body 30 is preferably 10 mm or more and 30 mm or less. For example, 14.1 mm is preferable, and φ20 mm is preferable as the diameter of the circumscribed circle. Further, the thickness Z of the resin body 30 is preferably 0.5 mm or more and 10 mm or less. For example, 2 mm is preferable.

[0071] In addition, the holes 181 to 184 in the top surface 301 have gate marks 171 to 174 corresponding to the four gates 571 to 574 which are resin injection ports. The distances between the holes 181 to 184 and the through holes 16 are the same. Further, the holes 181 to 184 are in the shape of a truncated cone, and the gate marks 171 to 174 are at the centers of the holes 181 to 184. The relative positions of each side surface 351 to 354 and each gate mark 171 to 174 are the same. Each side surface 351 to 354 and each gate mark 171 to 174 are rotationally symmetric with respect to the virtual line C0.

[0072] <Third Embodiment> Next, the polygon mirror 3 according to the third embodiment will be described. In the third embodiment, the description of the same configurations as those in the first embodiment and the second embodiment will be omitted.

[0073] Figs. 11(a) and 11(b) are perspective views of the resin body 30A in the polygon mirror 3 according to the third embodiment. Fig. 11(a) is a top perspective view of the resin body 30A in the polygon mirror 3 according to the third embodiment, and Fig. 11(b) is a bottom perspective view of the resin body 30A in the polygon mirror 3 according to the third embodiment. Fig. 12(a) is a cross-sectional view of the resin body 30A according to the third embodiment. Fig. 12(a) shows a cross-section of the resin body 30A along the line XII-XII in Fig. 11(a). Fig. 12(b) is an enlarged view of the main part of the resin body 30A shown in Fig. 12(a). Fig. 13 shows a cross-section of the resin body 30A along the line XIII-XIII in Fig. 11(a).

[0074] In the third embodiment, the configuration of the resin body 30A of the polygon mirror 3 is different from that of the second embodiment. That is, in the second embodiment, the case where the bottom surface has the recessed portions 321 to 324 was described, but in the third embodiment, the case where the bottom surface has the second protrusion will be described.

[0075] In this embodiment, the top surface 301A has the protrusions 611, 612, 613, and 614, and either the side surfaces 6112, 6122, 6132, 6142 in the direction perpendicular to the virtual line C0 of the protrusions 611 to 614 or the side surfaces 6113, 6123, 6133, 6143 in the rotation direction of the resin body 30A are inclined surfaces with respect to the virtual line C0, which is the same configuration as in the second embodiment.

[0076] A configuration of the bottom surface 302A, which is different from that of the second embodiment, will be described. The second intersection line 320 is used as a second height reference in the direction from the second intersection line of the second surface and the outer surface to the first intersection line 310. The bottom surface 302A has second protrusions 621, 622, 623, 624 that protrude with respect to the second reference on the side opposite to the side of the top surface 301A and have the same phase as the outer surfaces 351 to 354 around the virtual line C0. The second protrusions 621 to 624 arranged on the diagonals L21 and L22 are four protrusions in this embodiment, but at least one protrusion may be provided. Further, the side surfaces 6212, 6222, 6232, 6242 of the second protrusions 621 to 624 in the direction perpendicular to the virtual line C0 may have inclined portions. Similarly, the side surfaces 6213, 6223, 6233, 6243 of the second protrusions 621 to 624 in the rotation direction of the resin body 30A may also have inclined portions. The second protrusions 621 to 624 form the inner surface 330.

[0077] The first protrusions 611 to 614 are provided at positions different from those of the second protrusions 621 to 624 in the direction from the first intersection line to the second intersection line. Specifically, they are arranged with a half-phase shift in the phase around the virtual line C0. Thereby, when a plurality of polygon mirrors 3 are stacked, they can be fitted together.

[0078] In this embodiment, the height H1 of the protrusions 611 to 614 is equal to the height H2 of the second protrusions 621 to 624, but it is not necessarily equal. The heights H1 and H2 are, for example, 0.3 mm, but may be in the range of 0.1 mm to 0.5 mm. The side surfaces 6112 to 6142 of the protrusions 611 to 614 in the direction perpendicular to the virtual line C0 are inclined with respect to the virtual line C0. The width W1 of the resin body 30A in the rotation direction of the protrusions 611 to 614 is smaller than the width W2 of the resin body 30A in the rotation direction between the second protrusions 621 to 624.

[0079] When a plurality of resin bodies 30A are stacked, a certain gap is formed between the top surface 301A of the lower resin body 30A and the bottom surface 302A of the upper resin body 30A, and the resin bodies 30A can be arranged at equal intervals.

[0080] Next, the parts different from the second embodiment will be described with respect to the mold used to manufacture the resin body 30A. FIGS. 14(a) and 14(b) are perspective views of the cavity 50A in the mold 140A according to the third embodiment. FIG. 14(a) is a top perspective view of the cavity 50A, and FIG. 14(b) is a bottom perspective view of the cavity 50A.

[0081] The bottom surface forming surface 502A has second recessed portions 721, 722, 723, and 724 whose phases around the virtual line C0 coincide with those of the side surface forming surfaces 551 to 554 and which are recessed with respect to the bottom surface forming surface 502A. The second recessed portions 721 to 724 whose phases around the virtual line C0 coincide with those of the side surface forming surfaces 551 to 554 are four second recessed portions in this embodiment, but at least one recessed portion may be provided. The second recessed portions 721 to 724 may have inclined portions. The second recessed portions 721 to 724 are molds corresponding to the second protrusions 621 to 624.

[0082] Since the manufacturing method of the polygon mirror 3 of the third embodiment is the same as that of the second embodiment, it will be omitted.

[0083] The present invention is not limited to the embodiments described above, and many modifications are possible within the technical idea of the present invention. Also, the effects described in the embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments.

[0084] In the above-described embodiment, the case where the resin body of the polygon mirror 3 is a quadrangular prism having four side surfaces has been described, but the present invention is not limited thereto. The resin body may be a prism having four or more side surfaces. In particular, the resin body is preferably a quadrangular prism, a pentagonal prism, or a hexagonal prism.

[0085] In the above-described embodiment, the case where the outer shapes of the top surface and the bottom surface of the resin body are regular quadrilaterals, that is, the lengths of the respective sides are the same, has been described. However, the present invention is not limited to this. The top surface and the bottom surface may be polygons with four or more sides, and the lengths of the respective sides may be different. However, in the image forming apparatus, a regular polygon is preferable.

[0086] In the above-described embodiment, the case where the number of protrusions and recesses is the same as the number of side surfaces has been described. However, the present invention is not limited to this. When the resin bodies are stacked in the vapor deposition process, the protrusions and the recesses, or the protrusions and the protrusions may be engaged with each other, and at least one or more protrusions and recesses may be provided. However, it is preferable that the number of protrusions and recesses is the same as or an integral multiple of the number of side surfaces. When the protrusions are not arranged on the diagonal line of the top surface, or when the protrusions do not need to be arranged at equal intervals, the protrusions and the recesses, or the protrusions and the protrusions may be engaged with each other.

[0087] As described above, the described embodiments can be appropriately changed without departing from the technical idea. For example, a plurality of embodiments can be combined. Further, some matters of at least one embodiment can be deleted or replaced.

[0088] In addition, new matters can be added to at least one embodiment. The disclosure of this specification includes not only what is explicitly described in this specification, but also all matters that can be grasped from this specification and the drawings attached to this specification.

[0089] The disclosure of this specification also includes the complementary set of the individual concepts described in this specification. That is, for example, if this specification describes that "A is larger than B", even if the description that "A is not larger than B" is omitted, it can be said that this specification discloses that "A is not larger than B". This is because when the description that "A is larger than B" is made, it is premised that the case where "A is not larger than B" is considered.

Explanation of Reference Numerals

[0090] 3 Polygon mirror 16 Through-hole 30 Resin body 301 Top surface (first surface) 302 Bottom surface (second surface) 311~314 Protrusion 330 Inner surface 351~354 Outer surface

Claims

1. A polygon mirror comprising a resin body including a first surface, a second surface facing the first surface, an inner surface intersecting the first surface and the second surface so as to surround a through hole extending from the first surface to the second surface, and a plurality of outer surfaces intersecting the first surface and the second surface on the side opposite to the inner surface, wherein a first intersection line between the first surface and the outer surface is used as a first reference for the height in the direction from the second intersection line between the second surface and the outer surface to the first intersection line, the first surface has a plurality of protruding portions protruding on the side opposite to the side of the second surface with respect to the first reference, the second intersection line is used as a second reference for the height in the direction, the second surface has a plurality of recessed portions recessed on the side of the first surface with respect to the second reference, and the protruding portions form the inner surface, characterized in that it is a polygon mirror.

2. A polygon mirror comprising a resin body including a first surface, a second surface facing the first surface, an inner surface intersecting the first surface and the second surface so as to surround a through hole extending from the first surface to the second surface, and a plurality of outer surfaces intersecting the first surface and the second surface on the side opposite to the inner surface, wherein a first intersection line between the first surface and the outer surface is used as a first reference for the height in the direction from the second intersection line between the second surface and the outer surface to the first intersection line, the first surface has at least one protruding portion protruding on the side opposite to the side of the second surface with respect to the first reference, the second intersection line is used as a second reference for the height in the direction, the second surface has at least one recessed portion recessed on the side of the first surface with respect to the second reference, and at least one of the side surfaces of the protruding portion on the side away from the inner surface and at least one side surface in the rotational direction of the resin body has an inclined portion inclined with respect to the rotation axis of the resin body, characterized in that it is a polygon mirror.

3. The polygon mirror according to claim 2, wherein the first surface has a plurality of the protruding portions.

4. The polygon mirror according to claim 2 or 3, wherein the second surface has a plurality of the recessed portions.

5. A polygon mirror comprising a resin body including a first surface, a second surface facing the first surface, an inner surface intersecting the first surface and the second surface so as to surround a through hole extending from the first surface to the second surface, and a plurality of outer surfaces intersecting the first surface and the second surface on the side opposite to the inner surface, Take the first intersection line between the first surface and the outer surface as the first height reference in the direction from the second intersection line between the second surface and the outer surface to the first intersection line. The first surface has a plurality of protruding portions protruding to the side opposite to the side of the second surface with respect to the first reference. Take the second intersection line as the second height reference in the direction. The second surface has a plurality of recessed portions recessing to the side of the first surface with respect to the second reference. The recessed portion is in contact with the inner surface, and is a polygon mirror characterized by this.

6. The polygon mirror according to claim 1 or 5, characterized in that the number of the recessed portions is the same as the number of the protruding portions.

7. The polygon mirror according to claim 1 or 5, characterized in that the surface of the side of the protruding portion away from the inner surface has an inclined portion inclined with respect to the central axis of the through hole.

8. The polygon mirror according to any one of claims 1 to 7, characterized in that the side surface of the recessed portion away from the inner surface has an inclined portion inclined with respect to the central axis of the through hole.

9. The polygon mirror according to any one of claims 1 to 8, characterized in that the height H of the protruding portion and the depth D of the recessed portion satisfy H > D.

10. The polygon mirror according to any one of claims 1 to 9, characterized in that the protruding portion is arranged at least partially overlapping with the recessed portion in the direction from the first intersection line to the second intersection line.

11. The polygon mirror according to any one of claims 1 to 10, characterized in that the number of the protruding portions is an integer multiple of the outer surface.

12. The polygon mirror according to any one of claims 1 to 11, characterized in that the height H of the protruding portion is 0.4 mm to 0.7 mm.

13. The polygon mirror according to any one of claims 1 to 12, characterized in that the depth D of the recessed portion is 0.1 mm to 0.35 mm.

14. The polygon mirror according to claim 2 or 7, characterized in that the inclination angle of the inclined portion is 10 degrees or more and 60 degrees or less.

15. The polygon mirror according to any one of claims 1 to 14, characterized in that the first surface has a recessed portion corresponding to the gate mark.

16. A polygon mirror including a resin body having a first surface, a second surface facing the first surface, an inner surface intersecting the first surface and the second surface so as to surround a through hole extending from the first surface to the second surface, and a plurality of outer surfaces intersecting the first surface and the second surface on the side opposite to the inner surface. Taking the first intersection line between the first surface and the outer surface as a first reference for the height in the direction from the second intersection line between the second surface and the outer surface to the first intersection line. The first surface has at least one first protrusion protruding to the side opposite to the second surface side with respect to the first reference. Taking the second intersection line as a second reference for the height in the direction. The second surface has at least one second protrusion protruding to the side opposite to the first surface side with respect to the second reference. The first protrusion and the second protrusion form the inner surface. The polygon mirror is characterized in that the first protrusion is provided at a position different from that of the second protrusion in the direction.

17. A polygon mirror according to any one of Claims 1 to 16, and A light deflector comprising a drive source for rotationally driving the polygon mirror.

18. A light source, and A light scanning device comprising the light deflector according to Claim 17 for deflecting light emitted from the light source.

19. An image forming apparatus comprising an image forming unit for forming an image on a sheet, wherein the image forming unit has an image carrier, and the light scanning device according to Claim 18 for scanning the surface of the image carrier with light.

Images