JP5752025B2 - Optical scanning device and image forming apparatus having the same - Google Patents

Description

  The present invention relates to an optical scanning device that scans a light beam onto a surface to be scanned such as a photoconductor, and more particularly, to adjust the plane mirror that reflects the beam light toward the surface to be scanned to adjust the curve of the scanning line on the surface to be scanned. The present invention relates to an optical scanning apparatus capable of correcting the above and an image forming apparatus including the same.

  An electrophotographic image forming apparatus includes an optical scanning device that irradiates a photoconductor with light and exposes the photoconductor. This optical scanning device passes through a light source such as a beam light, a polygon mirror that reflects light from the light source, a motor that rotates the polygon mirror, an fθ lens that forms an image of light from the polygon mirror on a photoconductor, and an fθ lens. A flat mirror for reflecting light to the photoconductor is provided. The beam light reflected from the plane mirror toward the photosensitive member is scanned in the main scanning direction according to the rotation of the polygon mirror.

  In a tandem color image forming apparatus in which a plurality of photoconductors are arranged along the transfer belt conveyance direction, beam light corresponding to each color is emitted from each optical scanning device toward each photoconductor. In such a color image forming apparatus, a plurality of toner images are superimposed on a transfer belt to form a color image. Therefore, it is necessary for each scanning line scanned on the surface of each photoconductor to have all line shapes accurately aligned. If the scanning lines are not aligned, the toner image on the transfer belt has a color shift. Will occur.

  One of the factors that cause irregularities in the scanning line shape is the deviation of the optical axis of the beam light from the light source incident on the polygon mirror. When the beam light is not incident perpendicularly to the reflecting surface of the polygon mirror but is shifted by a slight angle, the light reaching distance to the photosensitive member changes in the main scanning direction, and thereby, on the surface of the photosensitive member, A parabolic scan line is drawn. For this reason, when the optical axis shift occurs in any one of the optical scanning devices, the line shapes of the scanning lines are not uniform.

  As a technique for correcting the shape of the scanning line on the surface of the photoconductor from a parabolic shape to a substantially linear shape, adjustment mechanisms described in Patent Documents 1 to 3 are known. As shown in FIG. 8, this type of adjusting mechanism is provided with a support member 103 that supports a flat plate-like mirror 101 (also referred to as a reflecting mirror or a folding mirror) that is long in the main scanning direction. The plane mirror 101 is mechanically bent in the direction opposite to the direction of change of the parabolic scanning line by pressing the portions other than the support points in the plane mirror 101. For example, when the flat mirror 101 is bent in a mortar shape, the back surfaces of both ends of the flat mirror 101 are pressed (see FIG. 8A), and when the flat mirror 101 is bent into a convex shape, the flat mirror 101 The center is pressed while pulling the back surfaces at both ends (see FIG. 8B). As a result, the change in the curve of the scanning line is canceled, and the line shape of the scanning line is corrected from a parabolic shape to a substantially linear shape.

JP 2001-1117040 A JP-A-8-146325 JP 2006-65310 A

  By the way, the cause of the irregular line shape of the scanning lines is not only the deviation of the incident angle of the light beam but also various factors. For example, minute irregularities, warpage, and distortion of the reflecting surfaces of the polygon mirror and the flat mirror caused by processing accuracy, environmental changes after molding, and the like are one of the causes. Another factor is the warp and distortion of the lens surface in various lenses through which the light beam is transmitted, or a minute difference in the internal distribution of the refractive index. Although color misregistration due to these other factors is minute, in recent years when high-quality printing such as photographic printing has been required of image forming apparatuses, such minute color misregistration cannot be ignored. The other factor is not that the line shape of the scanning line is curved into a simple quadratic curve such as a parabolic shape, but a curve having a plurality of peaks or valleys in the main scanning direction (hereinafter referred to as a “multi-uneven curve”). .), For example, an M-shaped curve gently undulating along the shape of the letter M, a W-shaped curve gently undulating along the shape of the letter W, and a shape of the letter N Curved like an N-shaped curve undulating. However, as shown in FIG. 8C, the conventional adjustment mechanism described above presses the center while pressing the back surfaces of both ends of the flat mirror 101, and curves the flat mirror 101 along the W shape. By doing so, it is possible to cancel out the change in the curve of the scanning line of the M-shaped curve, but it is not possible to correct the other curve of the multi-undulation curve.

  Accordingly, the present invention has been made in view of the above circumstances, and an object thereof is to provide an optical scanning device capable of correcting bending of a curved scanning line with many undulations and an image forming apparatus provided with the optical scanning device. There is to do.

(1) The present invention includes a long plate-like plane mirror extending along the main scanning direction that reflects the beam light emitted from the light source and deflected in the main scanning direction by the polygon mirror toward the surface to be scanned; And a correction mechanism that corrects the curvature of the scanning line due to the light beam on the scanning surface. The correction mechanism is provided outside the scanning region of the beam light by the polygon mirror, a first support portion that supports a central portion in the longitudinal direction of the plane mirror on the reflection surface side of the plane mirror, and a beam by the polygon mirror A second support portion provided outside the light scanning region and supporting a supported portion defined between the central portion and an end portion in the longitudinal direction of the plane mirror; and on the back side of the plane mirror, A first pressing point defined between the first supporting part and the second supporting part, a second pressing point defined at a part extending from the second supporting part to the longitudinal end of the flat mirror, and And an adjustment unit capable of pressing the flat mirror at each of the longitudinal center points of the back surface of the flat mirror and adjusting the pressing force.

  As a result, even if the scanning line on the surface to be scanned has a curved shape including multiple undulations (multi-undulation shape), the plane mirror can be bent according to the bending of the multiple undulation shape, and various line shapes It is possible to make corrections corresponding to the above. In particular, regardless of whether the line shape of the scanning line is an M-shaped curve or a W-shaped curve, the optical scanning device of the present invention can easily correct the bending of the scanning line only by the adjustment unit.

(2) The optical scanning device according to the present invention includes a release unit that releases the support of the plane mirror by the first support unit when the plane mirror is pressed and receives a force exceeding a predetermined set value. Is further provided.

  Accordingly, the plane mirror can be curved with the first support portion as a support point, and the support position of the first support portion is moved to support the both sides of the first support portion as support points. It is also possible to curve the plane mirror.

(3) The first pressing point is an intermediate point between the first supporting portion and the second supporting portion, and the second pressing point is an end portion in the longitudinal direction of the flat mirror.

  Thereby, correction corresponding to the M-shaped curve or the W-shaped curve can be performed.

 (4) The optical scanning device of the present invention further includes a case for accommodating the polygon mirror and the correction mechanism. The adjustment unit has a screw screwed into a screw hole that penetrates the wall surface of the case facing the back surface of the flat mirror, and the top of the screw exposed outside the case is rotated in one direction. Thus, the screw is configured to be able to press the flat mirror.

  Thereby, the said adjustment part is concretely realizable with a very simple structure with few number of parts. As a result, a compact optical scanning device is realized.

(5) The present invention may be an image forming apparatus including any of the optical scanning devices described above. The present invention is also preferably applied to such an image forming apparatus.

  According to the present invention, it is possible to correct bending of a curved scanning line with many undulations.

1 is a schematic cross-sectional view illustrating a schematic configuration of a printer 10 including an optical scanning device 30 according to an embodiment of the present invention. It is the elements on larger scale of the principal part II of FIG. 1, Comprising: The structure of the optical scanning device 30 which concerns on embodiment of this invention is shown. 3 is a schematic diagram illustrating an arrangement of optical devices of the optical scanning device 30. FIG. FIG. 4 is a partial cross-sectional view schematically showing a cross-sectional structure taken along a cutting line IV-IV in FIG. 2 and a cross-sectional structure taken along a cutting line IVB-IVB in FIG. FIG. 5 is a partial cross-sectional view schematically showing a cross-sectional structure taken along a cutting line VV in FIG. It is a schematic diagram for demonstrating the method of curving the deflection | deviation mirror 37A. It is a perspective view which shows typically the structure of the other Example of this invention. It is a schematic diagram for demonstrating the conventional correction | amendment method of a scanning line curve.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. The embodiment described below is merely an example embodying the present invention, and the embodiment of the present invention can be changed as appropriate without departing from the scope of the present invention.

[Printer 10]
First, a schematic configuration of a printer 10 (an example of an image forming apparatus of the present invention) according to an embodiment of the present invention will be described with reference to FIG. Note that the configuration not described here is the same as that of a general electrophotographic image forming apparatus, and thus description of the configuration is omitted. The printer 10 is only an example of the image forming apparatus according to the present invention. For example, a facsimile machine and a multifunction peripheral also correspond to the image forming apparatus according to the present invention.

  As shown in FIG. 1, the printer 10 includes four image forming units 11, two optical scanning devices 30 (an example of the optical scanning device of the present invention), an intermediate transfer belt 12, a secondary transfer device 13, and a paper feeding device. 14, a fixing device 15, and a paper discharge unit 16. The printer 10 also includes a control unit (not shown) having a CPU, ROM, RAM, and the like, an operation display unit (not shown) for performing various operation inputs and information display, and the like. Each of the two optical scanning devices 30 corresponds to each of the two image forming units 11 and is disposed below each image forming unit 11.

  In the present embodiment, an example in which two optical scanning devices 30 corresponding to the four image forming units 11 are provided in the printer 10 will be described. For example, four optical scanning devices 30 corresponding to the four image forming units 11 are provided. The present invention can also be applied to a printer 10 having a configuration in which two optical scanning devices are individually provided or a configuration in which one optical scanning device capable of supporting four image forming units 11 is provided.

  The four image forming units 11 are of a general electrophotographic system corresponding to four colors of black, yellow, cyan, and magenta in order from the right in FIG. Each image forming unit 11 includes a photosensitive drum 11A, a charging device 11B, a developing device 11C, a primary transfer roller 11D, and a cleaning device 11E.

  In the printer 10, an image is formed on the printing paper supplied from the paper feeding device 14 according to the following procedure. First, the photosensitive drum 11A is uniformly charged to a predetermined potential by the charging device 11B. Next, the light scanning device 30 scans the surface of the photosensitive drum 11A (corresponding to the surface to be scanned of the present invention) with beam light based on the image data, and an electrostatic latent image is formed on the surface. Then, the electrostatic latent image on the photosensitive drum 11A is developed as a toner image by the developing device 11C. Thereafter, the toner image on the photosensitive drum 11A is transferred to the intermediate transfer belt 12 that travels in the direction indicated by the arrow 19 in FIG. 1 by the primary transfer roller 11D. When the toner image is transferred to the intermediate transfer belt 12, the photosensitive drum 11A is cleaned by the cleaning device 115.

  In this way, when the toner images are sequentially transferred onto the intermediate transfer belt 12 by the image forming units 11, a color image is formed on the intermediate transfer belt 12. The color image on the intermediate transfer belt 12 is transferred to the printing paper by the secondary transfer device 13. Thereafter, when the toner image on the printing paper is melted and fixed by the fixing device 15, the printing paper is discharged to the paper discharge unit 16.

[Optical scanning device 30]
Next, the optical scanning device 30 will be described with reference to FIGS. 3 to 6 show the optical scanning device 30 with a simplified configuration for easy understanding. The optical scanning device 30 emits beam light toward the photosensitive drum 11A and scans the surface of the photosensitive drum 11A with the beam light. As shown in FIGS. 2 and 3, the optical scanning device 30 includes a light source 31 (see FIG. 3) that emits beam light, a polygon mirror 32, a motor 33, a driver board 34, fθ lenses 35A and 35B, and a deflection mirror 37A. , 37B, 37C, an adjustment mechanism 40 (an example of a correction mechanism of the present invention) for bending a deflection mirror 37A (an example of a flat mirror of the present invention), and a case 39 (an example of a case of the present invention) for accommodating them. ing.

  The optical scanning device 30 is provided with two sets of a light source 31, fθ lenses 35A and 35B, and deflection mirrors 37A, 37B, and 37C for one polygon mirror 32. In FIG. 3, a set of light sources 31, fθ lenses 35A and 35B, and deflection mirrors 37A, 37B, and 37C are shown, and the other set of illustrations is omitted.

  As shown in FIG. 2, the case 39 includes a case main body 51 and a lid body 52. The case main body 51 is formed in a box shape having a bottom with an open upper surface, and is configured such that a lid 52 covers the upper surface. The case body 51 has a substantially parallel middle plate 54 along its bottom surface. The inside of the case body 51 is below the upper layer chamber 55 and the middle plate 54 above the middle plate 54 by the middle plate 54. It is separated from the lower lower layer chamber 56. In the present embodiment, the light source 31, the motor 33, the driver substrate 34, the fθ lenses 35 </ b> A and 35 </ b> B, and the deflection mirror 37 </ b> A are provided in the upper layer chamber 55. In addition, deflection mirrors 37 </ b> B and 37 </ b> C are provided in the lower layer chamber 56.

  The polygon mirror 32 is made of aluminum, and is a rotating multi-faceted boundary having six reflecting surfaces that reflect the beam light from the light source 31. The polygon mirror 32 is formed in a regular hexagonal shape in plan view. A motor 33 is provided below the polygon mirror 32. That is, the polygon mirror 32 is provided vertically above the motor 33. A polygon mirror 32 is connected to the output shaft of the motor 33. Thereby, when the motor 33 is rotationally driven by the driver substrate 34, the polygon mirror 32 is rotated with the output shaft as the rotation center axis.

  As shown in FIG. 3, the deflection mirror 37 </ b> A is formed in a long plate shape that extends along the main scanning direction in which the beam light is scanned by the polygon mirror 32. The deflection mirror 37A is disposed downstream of the fθ lens 35B in the light beam traveling direction and upstream of the deflection mirror 37B. The deflection mirror 37 </ b> A is disposed near the upper corner of the case 39 in the upper layer chamber 55 and is supported by the intermediate plate 54. The support structure for the deflection mirror 37A will be described later.

  As shown in FIG. 2, when the polygon mirror 32 is rotated by the motor 33, the beam light emitted from the light source 31 (see FIG. 3) toward the polygon mirror 32 is reflected by the polygon mirror 32, and the optical path 43 (refer to the wavy line with an arrow in FIG. 2) and guided to the surface of the photosensitive drum 11A. Specifically, the beam light emitted in the horizontal direction from the light source 31 is scanned in the horizontal direction by being reflected by a reflection surface whose reflection angle is changed as needed by the rotation of the polygon mirror 32. Then, the light beam reaches the deflection mirror 37A through the fθ lens 35A and the fθ lens 35B. The light beam that has reached the deflection mirror 37 is reflected downward, passes through the transparent plate 58 fitted in the intermediate plate 54, proceeds to the deflection mirror 37B, and is sequentially reflected by the deflection mirror 37B and the deflection mirror 37C. The light is deflected toward the surface of the photosensitive drum 11A. The beam light reflected by the deflection mirror 37C passes through the transparent plate 59 fitted in the intermediate plate 54 and the transparent plate 60 fitted in the lid 52 and reaches the photosensitive drum 11A, and the surface of the photosensitive drum 11A. Thus, scanning is performed in the main scanning direction (longitudinal direction of the photosensitive drum 11A).

(Adjustment mechanism 40)
As described above, the optical scanning device 30 is provided with the adjusting mechanism 40. The adjustment mechanism 40 corrects the curvature of the scanning line due to the light beam on the surface of the photosensitive drum 11A. As shown in FIG. 4, one central support 63 and 2 for supporting the deflection mirror 37A. There are two side support portions 64 and five set screws 65 (65A, 65B, 65C, 65D, 65E) for bending the deflection mirror 37A. In addition, the center support part 63 is an example of the 1st support part of this invention, and the side support part 64 is an example of the 2nd support part of this invention. Moreover, the set screw 65 is an example of the adjusting portion of the present invention.

  FIG. 4A is a partial cross-sectional view schematically showing a cross-sectional structure taken along section line IV-IV in FIG. As shown in FIG. 4A, the center support portion 63 supports the center portion in the longitudinal direction of the deflection mirror 37A, and the lower support piece 63A attached to the upper surface of the intermediate plate 54 and the lid body 52. And an upper support piece 63B attached to the back surface of the. The side support portion 64 supports a supported portion defined between the central portion in the longitudinal direction of the deflection mirror 37A and both end portions in the same direction. Specifically, the side support portion 64 supports a portion separated from the both ends of the deflection mirror 37A by a predetermined distance D from the center side. The side support portion 64 includes a lower support piece 64 </ b> A attached to the upper surface of the middle plate 54 and an upper support piece 64 </ b> B attached to the back surface of the lid body 52. The center support portion 63 and the side support portion 64 both have a scanning region 68 of the beam light (see the wavy line in FIG. 4) and a scanning region 68 and a light path so as not to cross the beam light from the polygon mirror 32. It is provided outside the optical path.

  FIG. 4B is a partial cross-sectional view schematically showing a cross-sectional structure taken along section line IVB-IVB in FIG. As shown in FIG. 4B, the lower support piece 64 </ b> A of the side support portion 64 is fixed to the upper surface of the intermediate plate 54, and the upper support piece 64 </ b> B is fixed to the back surface of the lid body 52. Although not shown, the other side support 64 on the opposite side of the deflection mirror 37A in the longitudinal direction similarly has the lower support piece 64A fixed to the upper surface of the intermediate plate 54, and the upper support piece 64B. Is fixed to the back surface of the lid 52. The lower end of the deflection mirror 37A is inserted into a cutout groove 71 formed in the lower support piece 64A, and the upper end thereof is supported by being inserted into a cutout groove 72 formed in the upper support piece 64B. . By being supported in this way, the upper and lower ends of the deflection mirror 37A are supported so as to sandwich the reflection surface 48 side of the deflection mirror 37A and the back surface 49 on the opposite side.

  FIG. 5 is a partial cross-sectional view schematically showing a cross-sectional structure taken along the cutting line VV in FIG. As shown in FIG. 5, the lower support piece 63 </ b> A of the center support portion 63 is fixed to the upper surface of the intermediate plate 54, and the upper support piece 63 </ b> B is fixed to the back surface of the lid body 52. As shown, the lower support piece 63A and the upper support piece 63B both support the reflection surface 48 side of the deflection mirror 37A, and do not support the back surface 49 side of the deflection mirror 37A.

  In the present embodiment, unlike the side support portion 64 that is completely fixed, the center support portion 63 is predetermined in the direction in which the deflection mirror 37A approaches the polygon mirror 32 (the direction of the arrow 74 in FIG. 5B). When a force exceeding the set value is received, it is supported so as to slide in the direction of the arrow 74 along the upper surface of the intermediate plate 54. Specifically, a slide groove 78 that is long in the left-right direction in FIG. 5 is formed in the intermediate plate 54, and a guide 79 that is inserted through the slide groove 78 is formed in the lower support piece 63 A. The guide 79 is formed in the slide groove 78. The lower support piece 63A is slidably supported by the intermediate plate 54 in the inserted state. In addition, a slide groove 80 that is long in the left-right direction in FIG. 5 is formed in the lid 52, and a guide 81 that is inserted through the slide groove 80 is formed in the upper support piece 63 </ b> B, and the guide 81 is inserted into the slide groove 80. In this state, the upper support piece 63B is slidably supported by the lid 52.

  Further, an adsorption member 83 (an example of a release portion of the present invention) is provided on the upper surface of the intermediate plate 54 on the side wall 45 side of the case 39 with respect to the lower support piece 63A. An adsorption member 84 (an example of a release portion of the present invention) is provided on the side wall 45 side of the support piece 63B. These adsorbing members 83 and 84 adsorb each of the supporting pieces 63A and 63B with a predetermined force in contact with the lower supporting piece 63A and the upper supporting piece 63B. The suction members 83 and 84 are provided at positions that do not interfere with the deflection mirror 37A when the central portion of the deflection mirror 37A is bent toward the side wall 45 in a state of being sucked with the support pieces 63A and 63B. As a specific example of the attracting members 83 and 84, a magnet that generates a magnetic attractive force can be considered. In this case, the lower support piece 63A and the upper support piece 63B are formed of a magnetic material. Since such adsorption members 83 and 84 are provided, even if a force less than a predetermined set value is received in the direction of the arrow 74, the central support portion 63 does not slide and a force exceeding the set value is applied. Only when it is received, it slides in the direction of the arrow 74 along the upper surface of the intermediate plate 54, and the support in the direction of the arrow 74 is released.

  As shown in FIG. 3, the five set screws 65 (65A, 65B, 65C, 65D, 65E) are disposed on the back surface 49 side of the deflection mirror 37A, and are separated from each other in the longitudinal direction of the deflection mirror 37A. In this state, it is attached to the lid body 52. Specifically, on the back surface 49 of the deflection mirror 37A, an intermediate position (corresponding to the first pressing point of the present invention) between the center support portion 63 and the side support portion 64 disposed on one side thereof is set to a position where it can be pressed. A set screw 65B is provided, and the set screw 65C is located at a position where an intermediate position (corresponding to the first pressing point of the present invention) between the central support 63 and the side support 64 disposed on the other side can be pressed. Is provided. A set screw 65A is provided on the back surface 49 of the deflection mirror 37A at a position where one end (corresponding to the second pressing point of the present invention) of the deflection mirror 37A can be pressed, and the other end. A set screw 65D is provided at a position where the portion (corresponding to the second pressing point of the present invention) can be pressed. A set screw 65E is provided at a position where the center position in the longitudinal direction of the back surface 49 of the deflection mirror 37A can be pressed.

  As shown in FIGS. 4B and 5, the set screw 65 is attached to an inclined wall 53 formed at the corner of the lid 52 on the side wall 45 side. Specifically, a screw hole 86 that penetrates the inclined wall 53 is formed in the inclined wall 53, and a set screw 65 is screwed into the screw hole 86 from the outside of the inclined wall 53. The set screw 65 is formed to have a screw length sufficiently longer than the distance from the inclined wall 53 to the deflection mirror 37A. With this configuration, the set screw 65 exposed to the outside of the inclined wall 53 is rotated in one direction (for example, clockwise direction), so that the set screw 65 moves the screw hole 86 to the inner side. Screwed. When the tip of the set screw 65 reaches the back surface 49 of the deflecting mirror 37A and is further screwed, the deflecting mirror 37A is pressed by the set screw 65 in a direction penetrating the back surface 49 toward the reflecting surface 48. The pressing force to the deflection mirror 37A can be adjusted by changing the screwing amount of the set screw 65. When deeply screwed, a large pressing force is applied, and the deflection mirror 37A is greatly curved. Further, when the screw is shallowly screwed, a small pressing force is applied, and the deflection mirror 37A is bent slightly. With the set screw 65 pressing the back surface 49, the set screw 65 is rotated in another direction (for example, counterclockwise direction), the pressing force by the set screw 65 is gradually reduced, and is further rotated in the same direction. As a result, the tip of the set screw 65 moves away from the back surface 49, and the pressure on the deflection 37A is released.

(Effect of embodiment)
Since the adjustment mechanism 40 is provided in the optical scanning device 30 as described above, even if the scanning line on the surface of the photosensitive drum 11A is curved, the four set screws 65 are operated to form the deflection mirror 37A in an appropriate shape. The scanning line curvature can be corrected by bending the scanning line. For example, as shown in FIG. 6A, in order to curve the deflecting mirror 37A in a mortar shape when viewed from the reflecting surface 48, the set screws 65A and 65D are operated to press both end portions of the back surface 49. Good. Further, as shown in FIG. 6B, in order to curve the deflecting mirror 37A from the reflecting surface 48 into a gentle convex shape, the set screws 65B and 65C are operated to make the back surface 49 at two points on the center side. What is necessary is just to press. In this case, it is necessary to apply a pressing force larger than the suction force by the suction member 83 to separate the support pieces 63A and 63B of the center support portion 63 from the suction member 83 and slide them in the direction of the arrow. Further, as shown in FIG. 6C, in order to curve the deflection mirror 37A into a W-shaped curve that gently undulates along the shape of the letter W as viewed from the reflecting surface 48, a set screw 65A is used. , 65D, 65E may be operated to press the back surface 49 at three points. Further, as shown in FIG. 6D, in order to curve the deflection mirror 37A into an M-shaped curve that gently undulates along the shape of the letter M when viewed from the reflecting surface 48, a set screw 65B is used. And 65C may be operated to press the back surface 49 at two points on the center side. In this case, it is necessary to apply a pressing force smaller than the suction force by the suction member 83 so that the support pieces 63 </ b> A and 63 </ b> B of the center support portion 63 are not separated from the suction member 83. Of course, the deflection mirror 37A can be bent in various shapes in the main scanning direction by adjusting the pressing force and the pressing location of the five set screws 65. As a result, even if the line shape of the scanning line is a curve having a large number of undulations, the deflection of the deflection mirror 37A according to the curve can be corrected.

  Further, since the five set screws 65 can be operated from one direction on the side wall 45 side, the operation and adjustment of the adjustment mechanism 40 are facilitated.

  In the above-described embodiment, the case main body 51 of the case 39 having the upper layer chamber 55 and the lower layer chamber 56 is provided with a plurality of deflection mirrors 37A, 37B, and 37C, and guides the beam light to the photosensitive drum 11A disposed above. For example, as shown in FIG. 7, the case main body 51 of the case 39 is provided with one deflection mirror 37A, and the light beam reflected by the deflection mirror 37A is disposed below as shown in FIG. The present invention can also be applied to the configuration leading to 11A.

  The present invention relates to an optical scanning apparatus capable of correcting the curvature of a scanning line on a surface to be scanned by adjusting a plane mirror that reflects light beams toward the surface to be scanned such as a photoconductor, and an image including the same. It can be used for a forming apparatus.

10: Printer 30: Optical scanning device 32: Polygon mirror 33: Motor 34: Driver substrate 35A, 35B: fθ lenses 37A, 37B, 37C: Deflection mirror 39: Case 40: Adjustment mechanism 63: Center support part 64: Side support part 83, 84: adsorption member

Claims (4)

An elongated plate-like plane mirror extending along the main scanning direction for reflecting the beam light emitted from the light source and deflected in the main scanning direction by the polygon mirror toward the surface to be scanned;
A correction mechanism for correcting the curvature of the scanning line due to the beam light on the scanned surface,
The correction mechanism is
A first support part that is provided outside the scanning region of the beam light by the polygon mirror and supports a central part in the longitudinal direction of the plane mirror on the reflection surface side of the plane mirror;
A second support part that is provided outside a scanning region of the beam light by the polygon mirror and supports a supported part defined between the center part and an end part in the longitudinal direction of the plane mirror;
On the back surface side of the flat mirror, a first pressing point defined between the first support portion and the second support portion, and a portion extending from the second support portion to an end portion in the longitudinal direction of the flat mirror. An adjusting unit capable of pressing the flat mirror and adjusting the pressing force at each of the determined second pressing point and the central point in the longitudinal direction of the back surface of the flat mirror;
An optical scanning device comprising: a release unit that releases support of the plane mirror by the first support unit when a force exceeding a predetermined set value is received by pressing the plane mirror . 2. The light according to claim 1 , wherein the first pressing point is an intermediate point between the first supporting portion and the second supporting portion, and the second pressing point is an end portion in a longitudinal direction of the flat mirror. Scanning device. A case for accommodating the polygon mirror and the correction mechanism;
The adjustment unit has a screw screwed into a screw hole that penetrates the wall surface of the case facing the back surface of the flat mirror, and the top of the screw exposed outside the case is rotated in one direction. wherein the Rukoto bis optical scanning device according to claim 1 or 2 is configured to be able to press said plane mirror. An image forming apparatus having an optical scanning apparatus according to any one of claims 1 to 3.