JP2016114713A - Optical scanning device and image formation device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanning device that suppresses a pose in a single body of optical scanning devices from being unstable, and allows a positioning boss to be prevented from being damaged.SOLUTION: Optical scanning devices 4a and 4b have: a housing 41; a light source units 43a and 43b; a polygon mirror 42; and a polygon motor 51. In a bottom face 41aa of a housing main body 41a, provided are: positioning bosses 61a and 61b engaging with engaging holes 73a and 73b of a main body frame 19 of a main body of an image formation device 100 to position the housing 41; and pose holding protrusions 62a, 62b, 64a and 64b holding a pose in a single body of the optical scanning devices 4a and 4b. A protrusion height with respect to the bottom face 41aa of the pose holding protrusions 62a, 62b, 64a and 64b is higher than that with respect to the bottom face 41aa of the positioning bosses 61a and 61b.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an optical scanning apparatus that scans a beam of light and writes and forms an image, and an image forming apparatus including the same, which are used in an image forming apparatus such as a printer, a copying machine, and a facsimile machine.

  2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic method such as a copying machine or a printer, a beam light (laser light) modulated based on input image data is applied to the surface of a photosensitive drum uniformly charged by a charging device. An optical scanning device that irradiates and scans is provided. An electrostatic latent image formed by the optical scanning device is developed into a toner image by a developing device, and further, the toner image is transferred onto a recording paper or the like, and then permanently fixed by a fixing device. An image forming process to form an image is performed.

  Such an optical scanning device includes a light source section such as an LD (laser diode), an optical member such as a polygon mirror, a scanning lens, and a plane mirror in a housing, and has high precision among the constituent units of the image forming apparatus. In addition, it is necessary to take into consideration the vibration accompanying the high-speed rotation of the polygon mirror and the thermal deformation due to the temperature rise.

  For example, in Patent Document 1, the components of the optical scanning device are mounted in advance on the inner side of the top plate of the housing case whose bottom surface is open, and the housing case is fixed to a tie bar placed on a pair of left and right jig blocks. A mounting structure of an optical scanning device for mounting and fixing a case to a main frame of a printer together with a tie bar is disclosed.

  In Patent Document 2, a first frame holding a plurality of optical components including a light beam generator and an optical deflector and a light beam output from the last optical component in the first frame are incident. Then, the second frame holding the light beam direction changing means for emitting in the direction in which the image forming surface exists is fixed and integrated with the second frame positioned with respect to the first frame. An optical scanning device is disclosed that includes frame integration means and frame fixing means for separately fixing the integrated first and second frames to a predetermined immovable member.

  In Patent Document 3, among a plurality of positioning portions provided in the optical box, positioning and fixing in the height direction is performed at three points, and separately from the three positioning portions, the height is increased via an elastic member. There is disclosed an optical scanning device that performs pressing in the vertical direction. Patent Document 4 includes first and second positioning portions having at least one positioning plate for positioning the optical box with respect to the supporting means, and the positioning plates are disposed in different directions. And an optical scanning device configured to position the optical box using the first or second positioning portion.

JP-A-8-22175 JP-A-8-244270 JP-A-8-278670 JP 2000-10036 A

  Conventionally, on the bottom surface of the optical scanning device, a fastening portion to which a screw for fixing the optical scanning device on the main body frame of the image forming apparatus is fastened and a positioning boss are provided. When the optical scanning device is attached to the planar main body frame, the positioning boss is formed so that the protruding height with respect to the bottom surface of the optical scanning device is larger than the fastening portion.

  However, since only two positioning bosses are normally provided on the bottom surface of the optical scanning device, the posture of the optical scanning device alone becomes unstable. In addition, since the positioning boss is likely to come into contact with other members, the positioning boss may be damaged.

  In view of the above-described problems, the present invention suppresses an unstable posture of an optical scanning device alone, and suppresses damage to a positioning boss, and an optical scanning device capable of suppressing the damage. An object is to provide an image forming apparatus provided.

  In order to achieve the above object, a first configuration of the present invention is an optical scanning device that includes a housing, a light source section, a polygon mirror, and a polygon motor, and deflects and scans a surface to be scanned. The housing includes a housing main body and an upper lid that is attached to an opening of the housing main body. The light source unit is supported by the housing body and emits beam light. The polygon mirror is disposed in the housing and deflects the beam light emitted from the light source unit. The polygon motor rotates the polygon mirror. On the bottom surface of the housing main body, a positioning boss for positioning the housing by engaging with an engagement hole of the main body frame of the image forming apparatus main body, and three or more posture holding protrusions for holding the single posture of the optical scanning device And are provided. The protruding height of the posture holding protrusion with respect to the bottom surface of the housing body is larger than the protruding height of the positioning boss with respect to the bottom surface of the housing body.

  According to the first configuration of the present invention, the protruding height of the posture holding protrusion with respect to the bottom surface of the housing body is larger than the protruding height of the positioning boss with respect to the bottom surface of the housing body. Thereby, since it can suppress that a positioning boss contacts another member when a housing main body is mounted, it can suppress that a positioning boss is damaged.

  In addition, three or more posture holding protrusions are provided on the bottom surface of the housing body. Thereby, it is possible to suppress the posture of the optical scanning device alone from becoming unstable.

1 is a schematic diagram showing an overall configuration of an image forming apparatus 100 equipped with optical scanning devices 4a and 4b according to an embodiment of the present invention. The perspective view which shows the internal structure of the optical scanning device 4a The top view which shows the internal structure of the optical scanning device 4a Side sectional view schematically showing the internal structure of the optical scanning device 4a The top view which looked at the optical scanning device 4a from the back side The perspective view which looked at the optical scanning device 4a from the light source part 43a, 43b side The perspective view which looked at the optical scanning device 4a from the opposite side of the light source parts 43a and 43b Sectional drawing by the side of the light source parts 43a and 43b of the optical scanning device 4a A perspective view of the main body frame 19 to which the optical scanning devices 4a and 4b are fixed. The perspective view which shows the state which fixed the optical scanning devices 4a and 4b to the main body frame 19 Sectional drawing which shows the structure around the vibration proof member 76 provided in the main body frame 19 of the image forming apparatus 100 of the modification of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an image forming apparatus 100 on which optical scanning devices 4a and 4b are mounted. Here, a tandem color image forming apparatus is shown. In the main body of the image forming apparatus 100, four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (the right side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively performed by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  These image forming portions Pa to Pd are provided with photosensitive drums 1a, 1b, 1c and 1d which carry visible images (toner images) of the respective colors, and are further illustrated by a driving means (not shown). 1, an intermediate transfer belt 8 that rotates in the clockwise direction is provided adjacent to each of the image forming portions Pa to Pd. The toner images formed on the photosensitive drums 1 a to 1 d are sequentially transferred onto the intermediate transfer belt 8 that moves while contacting the photosensitive drums 1 a to 1 d, and then transferred onto the transfer paper at the secondary transfer roller 9. The image is transferred onto P at a time, and further fixed on the transfer paper P in the fixing unit 7 and then discharged from the apparatus main body. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d in the counterclockwise direction in FIG.

  The transfer paper P onto which the toner image is transferred is accommodated in a paper cassette 16 at the lower part of the main body of the image forming apparatus 100, and is conveyed to the secondary transfer roller 9 via the paper feed roller 12a and the registration roller pair 12b. . A sheet made of dielectric resin is used for the intermediate transfer belt 8, and a (seamless) belt mainly having no seam is used.

  Next, the image forming units Pa to Pd will be described. Around the photosensitive drums 1a to 1d rotatably arranged, there are chargers 2a, 2b, 2c and 2d for charging the photosensitive drums 1a to 1d, and image information to the photosensitive drums 1a to 1d. Scanning devices 4a and 4b for exposing the toner, developing units 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and a developer (toner) remaining on the photosensitive drums 1a to 1d. Cleaning portions 5a, 5b, 5c, and 5d are provided for removing water. The optical scanning devices 4 a and 4 b are fixed to the main body frame 19 of the image forming apparatus 100 with screws.

  When the start of image formation is input by the user, the surfaces of the photosensitive drums 1a to 1d are first uniformly charged by the chargers 2a to 2d, and then the laser beams are irradiated by the optical scanning devices 4a and 4b. Electrostatic latent images corresponding to image signals are formed on the body drums 1a to 1d. Each of the developing units 3a to 3d is filled with a predetermined amount of cyan, magenta, yellow, and black toner by a replenishing device (not shown). This toner is supplied onto the photosensitive drums 1a to 1d by the developing units 3a to 3d and electrostatically attached thereto, so that the toner corresponds to the electrostatic latent image formed by exposure from the optical scanning devices 4a and 4b. A toner image is formed.

  After an electric field is applied between the primary transfer rollers 6a to 6d and the intermediate transfer belt 8 at a predetermined transfer voltage, cyan, magenta, yellow, and yellow on the photosensitive drums 1a to 1d are applied by the primary transfer rollers 6a to 6d. The black toner image is transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, residual toner on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning units 5a to 5d in preparation for the subsequent formation of a new electrostatic latent image.

  The intermediate transfer belt 8 is stretched between an upstream transport roller 10 and a downstream drive roller 11, and the intermediate transfer belt 8 rotates clockwise as the drive roller 11 is rotated by a drive motor (not shown). When rotation in the direction starts, the transfer paper P is conveyed from the registration roller pair 12b to the secondary transfer roller 9 provided adjacent to the intermediate transfer belt 8 at a predetermined timing, and the full color formed on the intermediate transfer belt 8 is formed. The image is transferred. The transfer paper P onto which the toner image is transferred is conveyed to the fixing unit 7.

  The transfer paper P conveyed to the fixing unit 7 is heated and pressed by the fixing roller pair 13 so that the toner image is fixed on the surface of the transfer paper P to be a permanent image. The transfer paper P on which the full-color image is fixed in the fixing unit 7 is distributed in the transport direction by the branching unit 14 that branches in a plurality of directions. When an image is formed on only one side of the transfer paper P, it is discharged as it is onto the discharge tray 17 by the discharge roller pair 15.

  On the other hand, when images are formed on both sides of the transfer paper P, most of the transfer paper P that has passed through the fixing unit 7 is discharged to the discharge tray 17, and then the discharge roller pair 15 is reversely rotated to be drawn into the apparatus again. . The drawn transfer paper P is distributed to the reversal conveyance path 18 by the branching section 14 and re-conveyed to the secondary transfer roller 9 with the image surface reversed. Then, after the next image formed on the intermediate transfer belt 8 is transferred by the secondary transfer roller 9 to the surface of the transfer paper P where the image is not formed, and conveyed to the fixing unit 7 to fix the toner image. , And discharged to the discharge tray 17.

  2 and 3 are a perspective view and a plan view showing the internal structure of the optical scanning device 4a of the present invention, respectively. FIG. 4 is a side sectional view schematically showing the internal structure of the optical scanning device 4a (FIG. 3). AA ′ arrow sectional view of FIG. 2 and 3 show a state in which the upper lid 41b is removed so that the inside of the optical scanning device 4a can be seen. Although the configuration of the optical scanning device 4a is described here, the configuration of the optical scanning device 4b is exactly the same.

  As shown in FIGS. 2 to 4, the optical scanning device 4a has a housing 41 composed of a housing main body 41a and an upper lid 41b, and a polygon mirror 42 is disposed at a substantially central portion of the housing main body 41a. . In the present embodiment, the polygon mirror 42 is composed of a regular hexagonal rotary polygon mirror having six deflection surfaces (reflection surfaces) on the side surface, and is rotated by the polygon motor 51 at a predetermined speed. The polygon motor 51 is fitted in a motor positioning hole 52 formed on the bottom surface of the housing body 41a.

  Further, two light source portions 43a and 43b are arranged on the side wall on the front side (lower side in FIG. 3) of the housing body 41a. The light source units 43a and 43b are constituted by LDs (laser diodes), and emit light beams (laser beams) D1 and D2 that are optically modulated based on image signals.

  Between the light source units 43a and 43b and the polygon mirror 42, two collimator lenses 44a and 44b provided corresponding to the light source units 43a and 43b, and the beam light D1 that has passed through the collimator lenses 44a and 44b. , D2 each having a predetermined optical path width, two cylindrical lenses 46a and 46b through which the beam lights D1 and D2 pass after passing through the first apertures 45a and 45b and the first apertures 45a and 45b, respectively, and the cylindrical Second apertures 47a and 47b are provided in which the light beams D1 and D2 that have passed through the lenses 46a and 46b respectively have predetermined optical path widths.

  The collimator lenses 44a and 44b make the light beams D1 and D2 emitted from the light source units 43a and 43b into substantially parallel light beams, respectively, and the cylindrical lenses 46a and 46b are in the sub-scanning direction (direction perpendicular to the paper surface of FIG. 3). Only have a predetermined refractive power. In the housing main body 41a, scanning lenses 48a and 48b are arranged opposite to each other with the polygon mirror 42 interposed therebetween. The scanning lenses 48a and 48b have fθ characteristics, and form an image of the beam light deflected and reflected by the polygon mirror 42 on the photosensitive drums 1a to 1d (see FIG. 1). Further, three plane mirrors (folding mirrors) 49a and 49b are arranged on the optical paths of the beam lights D1 and D2 from the scanning lenses 48a and 48b to the photosensitive drums 1a to 1d (see FIG. 1), respectively.

  The beam scanning operation by the optical scanning device 4a configured as described above will be described. First, as shown in FIGS. 2 and 3, the light beams D1 and D2 emitted from the light source units 43a and 43b are made into substantially parallel light beams by the collimator lenses 44a and 44b, and are predetermined by the first apertures 45a and 45b. The optical path width. Next, the beam lights D1 and D2 that have become substantially parallel light beams are incident on the cylindrical lenses 46a and 46b. The light beams D1 and D2 incident on the cylindrical lenses 46a and 46b are in the state of parallel light beams as they are in the main scanning section, converged and emitted in the sub-scanning direction, and have a predetermined optical path width by the second apertures 47a and 47b. After that, a line image is formed on the deflection surface of the polygon mirror 42.

  The light beams D1 and D2 incident on the polygon mirror 42 are deflected at a constant angular velocity by the polygon mirror 42 and then deflected at a constant velocity by the scanning lenses 48a and 48b. As shown in FIG. 4, the light beams D1 and D2 that have passed through the scanning lenses 48a and 48b are folded back a predetermined number of times (here, three times) by the plane mirrors 49a and 49b arranged in the respective optical paths, and formed on the upper lid 41b. The light is distributed to the photosensitive drums 1c and 1d through the window portion 54. Similarly, the beam light emitted from the optical scanning device 4b is distributed to the photosensitive drums 1a and 1b.

  5 is a plan view of the optical scanning device 4a viewed from the back side, FIGS. 6 and 7 are perspective views of the optical scanning device 4a viewed from the light source units 43a and 43b and the opposite side, respectively, and FIG. FIG. 9 is a perspective view of the body frame 19 to which the optical scanning devices 4a and 4b are fixed. The structure for attaching the optical scanning devices 4a and 4b to the body frame 19 will be described with reference to FIGS. The optical scanning device 4a will be described below, but the same applies to the optical scanning device 4b.

  As shown in FIG. 5, a first fastening portion 60a, a second fastening portion 60b, and a third fastening portion 60c are provided on the bottom surface 41aa of the housing body 41a. The first fastening portion 60a to the third fastening portion 60c project annularly from the bottom surface 41aa of the housing body 41a, and a through hole into which a screw 80 (see FIG. 7) is inserted is formed at the center. The three fastening portions (first fastening portion 60 a to third fastening portion 60 c) have bottom surfaces in contact with the main body frame 19, and position the housing main body 41 a with respect to the main body frame 19 in the height direction.

  The 1st fastening part 60a and the 2nd fastening part 60b are arrange | positioned so that the light source parts 43a and 43b may be pinched | interposed into the light source parts 43a and 43b side (lower side of FIG. 5) of bottom face 41aa. The 3rd fastening part 60c is arrange | positioned on the opposite side (upper side of FIG. 5) with the light source parts 43a and 43b. Thereby, the light source parts 43a and 43b side of the housing main body 41a can be stably fastened to the main body frame 19.

  Positioning bosses 61a and 61b for positioning the housing main body 41a in the surface direction (horizontal direction) with respect to the main body frame 19 project from the light source portions 43a and 43b side of the bottom surface 41aa and the opposite side (upper and lower ends in FIG. 5). Has been. The positioning bosses 61a and 61b are respectively arranged in the center of the housing body 41a in the width direction (left and right direction in FIG. 5). Moreover, the protrusion height with respect to the bottom face 41aa of the positioning boss | hubs 61a and 61b is larger than the protrusion height with respect to the bottom face 41aa of the 1st fastening part 60a-the 3rd fastening part 60c.

  As shown in FIGS. 6 and 7, the bottom surface 41aa has a cooling duct 63 having a shape in which the center portion in the width direction (left-right direction in FIG. 5) is recessed inwardly across the light source portions 43a and 43b and the opposite side. Is provided. The cooling duct 63 has an air inlet 63a on the side opposite to the light source parts 43a and 43b, and an air outlet 63b on the light source parts 43a and 43b side.

  As shown in FIG. 5, when the cooling duct 63 is viewed from the bottom surface 41aa side, the central portion is greatly opened, and when the optical scanning device 4a is fixed to the main body frame 19 (see FIG. 9), the main body frame 19 Constitutes a part of the bottom surface of the cooling duct 63. Further, at both ends of the cooling duct 63 (in the vicinity of the intake port 63a and the exhaust port 63b), a bottom surface 41aa is left in a bridging manner and constitutes a part of the bottom surface of the cooling duct 63. Positioning bosses 61a and 61b are projected outward (downward) on the bridge-shaped bottom surface 41aa.

  A polygon motor 51 that protrudes into the cooling duct 63 when an air flow generated by a cooling fan (not shown) flows in the cooling duct 63 from the intake port 63a toward the exhaust port 63b (in the direction of the arrow in FIG. 5). Cool (see FIG. 4). Thereby, thermal deformation of the housing main body 41a due to heat radiation from the polygon motor 51 can be suppressed.

  Further, posture holding protrusions 62a, 62b, 64a and 64b for holding the posture of the optical scanning device 4a as a single unit protrude from the light source portions 43a and 43b side of the bottom surface 41aa and the opposite side (upper and lower ends in FIG. 5). It is installed. The posture holding protrusions 62a and 62b are disposed adjacent to the cooling duct 63 on the light source portions 43a and 43b side (lower side in FIG. 5) of the bottom surface 41aa. The posture holding protrusions 64a and 64b are arranged on both sides of the housing body 41a in the width direction (left and right direction in FIG. 5) on the opposite side (upper side in FIG. 5) of the bottom surface 41aa to the light source parts 43a and 43b.

  The protruding heights of the attitude holding protrusions 62a, 62b, 64a and 64b with respect to the bottom surface 41aa are larger than the protruding heights of the positioning bosses 61a and 61b with respect to the bottom surface 41aa. In addition, the protrusion height with respect to the bottom face 41aa of the posture holding protrusions 62a, 62b, 64a, and 64b is substantially the same.

  As shown in FIG. 8, a skew adjustment mechanism (mirror adjustment mechanism) 90 for adjusting an optical path shift (skew) with respect to the surfaces (scanned surfaces) of the photosensitive drums 1c and 1d is provided in the housing main body 41a. It has been. The skew adjusting mechanism 90 rotates the adjusting knobs 90a and 90b (see FIG. 6) in a predetermined direction, thereby pressing the flat mirrors 49a and 49b disposed in the immediate vicinity of the window portion 54 in the longitudinal direction. Is reciprocated in the vertical direction with respect to the reflecting surfaces of the plane mirrors 49a and 49b, and the inclination of the plane mirrors 49a and 49b in the longitudinal direction is adjusted. Further, a screw 70 for reciprocating a cleaning member (not shown) for cleaning the window portion 54 along the window portion 54 is provided on the upper surface (upper lid 41b) of the optical scanning device 4a.

  A portion of the bottom surface 41aa of the housing body 41a where the skew adjustment mechanism 90 is provided is a trapezoidal protrusion that protrudes outward (downward) in order to avoid contact with the skew adjustment mechanism 90. And this protrusion part serves as attitude | position holding protrusion 62a, 62b.

  The main body frame 19 is made of sheet metal, and as shown in FIG. 9, screws 80 are fastened at positions facing the first fastening portion 60a to the third fastening portion 60c of the housing main body 41a when the optical scanning device 4a is installed. Screw fastening holes 71a to 71c to be formed are formed. Further, engaging holes 73a and 73b for engaging the positioning bosses 61a and 61b are formed at positions facing the positioning bosses 61a and 61b of the housing body 41a.

  In addition, opening holes 72a, 72b, 74a, and 74b into which the posture holding protrusions 62a, 62b, 64a, and 64b are fitted are formed at positions facing the posture holding protrusions 62a, 62b, 64a, and 64b of the housing body 41a. . The opening holes (first opening holes) 72 a and 72 b are formed so as to allow air flow to pass therethrough and to communicate with the cooling duct 63 in a state in which the posture holding protrusions 62 a and 62 b are fitted.

  When the optical scanning device 4a is attached to the main body frame 19, the polygon mirror 42, the light source portions 43a and 43b, the apertures 47a and 47b, the scanning lenses 48a and 48b, etc. in the housing main body 41a are first positioned, and then the housing main body 41a. Is placed on the main body frame 19. Then, the attitude holding projections 62a, 62b, 64a, 64b of the housing main body 41a are fitted into the opening holes 72a, 72b, 74a, 74b of the main body frame 19, and the positioning bosses 61a, 61b of the housing main body 41a are engaged with the main body frame 19. Engage with the mating holes 73a and 73b. As a result, the housing main body 41 a is positioned with respect to the main body frame 19. Thereafter, the first fastening portion 60 a to the third fastening portion 60 c and the screw fastening holes 71 a to 71 c of the main body frame 19 are fastened with the screws 80, so that the optical scanning device 4 a is fixed to the main body frame 19.

  The optical scanning device 4b is attached by the same procedure, and the attachment of the optical scanning devices 4a and 4b to the main body frame 19 is completed. FIG. 10 shows a state in which the optical scanning devices 4 a and 4 b are fixed to the main body frame 19.

  In the present embodiment, as described above, the protrusion height of the posture holding protrusions 62a, 62b, 64a, 64b with respect to the bottom surface 41aa of the housing body 41a is higher than the protrusion height of the positioning bosses 61a, 61b with respect to the bottom surface 41aa of the housing body 41a. large. Thereby, since it can suppress that the positioning boss | hubs 61a and 61b contact with another member when the housing main body 41a is mounted, it can suppress that the positioning boss | hubs 61a and 61b are damaged.

  Further, the bottom surface 41aa of the housing body 41a is provided with three or more (four in this case) posture holding protrusions 62a, 62b, 64a, 64b. Thereby, it is possible to suppress the posture of the optical scanning devices 4a and 4b from being unstable.

  Further, as described above, a portion of the bottom surface 41aa of the housing main body 41a where the skew adjustment mechanism 90 is provided is a protruding portion that protrudes outward in order to avoid contact with the skew adjustment mechanism 90. As a result, it is possible to prevent the entire housing main body 41a from becoming high, and thus it is possible to prevent the image forming apparatus 100 from increasing in size. Further, since the projecting portion also serves as the posture holding projections 62a and 62b, the structure can be simplified as compared with the case where the posture holding projection is separately provided on the light source portions 43a and 43b side.

  Further, as described above, the protruding height of the positioning bosses 61a and 61b with respect to the bottom surface 41aa of the housing body 41a is larger than the protruding height of the first fastening portion 60a to the third fastening portion 60c with respect to the bottom surface 41aa of the housing body 41a. Thereby, since it can fully suppress that the 1st fastening part 60a-the 3rd fastening part 60c contact with another member, it is enough to damage the 1st fastening part 60a-the 3rd fastening part 60c. Therefore, positioning accuracy in the height direction can be ensured.

  As described above, the main body frame 19 is provided with the opening holes 72a, 72b, 74a, and 74b into which the posture holding protrusions 62a, 62b, 64a, and 64b are fitted. This prevents the posture holding projections 62a, 62b, 64a, 64b from contacting the main body frame 19 in a state where the optical scanning devices 4a, 4b are arranged at the mounting position of the main body frame 19, and the positioning bosses 61a, 61b are The housing 41 can be easily positioned by being engaged with the engagement holes 73 a and 73 b of the main body frame 19. Further, the opening holes 72 a and 72 b are formed so that the air flow can pass through the protrusions (posture holding protrusions 62 a and 62 b) and the communication with the cooling duct 63. Thereby, the opening holes 72a and 72b function as air vent holes for the airflow passing through the cooling duct 63, and the flow of the airflow in the cooling duct 63 can be prevented from being lowered (becomes worse).

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above-described embodiment, the two-beam type optical scanning devices 4a and 4b including the two light source units 43a and 43b have been described. However, the present invention is not limited to the two-beam type optical scanning device and includes four light source units. The present invention can be applied in exactly the same manner to a four-beam type optical scanning apparatus equipped with a single beam type optical scanning apparatus mounted on a monochrome copying machine or a monochrome printer.

  Moreover, you may comprise so that the vibration of optical scanning device 4a, 4b may be suppressed. In this case, for example, as in the image forming apparatus 100 according to the modification of the present invention illustrated in FIG. 11, the vibrations of the optical scanning devices 4 a and 4 b may be suppressed using the posture holding protrusion. Specifically, the vibration isolating member 76 made of an annular elastic member is attached to the opening holes 74 a and 74 b of the main body frame 19, and the posture holding protrusions 64 a and 64 b are fitted into the through holes in the central portion of the vibration isolating member 76 to make contact. Let With this configuration, even when the polygon mirror 42 is rotated at a high speed, the vibration can be absorbed by the vibration isolation member 76, so that the occurrence of jitter (image disturbance) due to the vibration of the housing 41 is suppressed. can do.

  INDUSTRIAL APPLICABILITY The present invention can be used in an optical scanning apparatus that is used in image forming apparatuses such as printers, copiers, and facsimiles and that scans light beams to write and form images.

19 Main body frame 4a, 4b Optical scanning device 41 Housing 41a Housing main body 41aa Bottom surface 41b Upper lid 42 Polygon mirrors 43a, 43b Light source portions 49a, 49b Plane mirror (folding mirror)
51 Polygon motor 60a First fastening part (fastening part)
60b Second fastening part (fastening part)
60c 3rd fastening part (fastening part)
61a, 61b Positioning bosses 62a, 62b Posture holding protrusion (protrusion)
63 Cooling ducts 64a and 64b Posture holding protrusions 72a and 72b Opening hole (first opening hole)
73a, 73b engagement hole 74a, 74b opening hole (second opening hole)
76 Anti-vibration member 80 Screw 90 Skew adjustment mechanism (mirror adjustment mechanism)
100 Image forming apparatus D1, D2 Beam light

Claims (6)

A housing composed of a housing main body and an upper lid mounted in an opening of the housing main body;
A light source unit supported by the housing body and emitting beam light;
A polygon mirror disposed in the housing and deflecting the beam light emitted from the light source unit;
A polygon motor for rotating the polygon mirror;
And an optical scanning device that deflects and scans the surface to be scanned.
On the bottom surface of the housing main body, a positioning boss for positioning the housing by engaging with an engagement hole of a main body frame of the image forming apparatus main body, and three or more holding the posture of the optical scanning device alone. A posture holding protrusion, and
The optical scanning device according to claim 1, wherein a protruding height of the posture holding protrusion with respect to the bottom surface of the housing body is larger than a protruding height of the positioning boss with respect to the bottom surface of the housing body. The housing is provided with a folding mirror that folds the beam light and guides it to the surface to be scanned, and a mirror adjustment mechanism that adjusts the inclination of the folding mirror in the longitudinal direction,
The portion of the bottom surface of the housing body where the mirror adjustment mechanism is provided is a protruding portion protruding outward in order to avoid contact with the mirror adjustment mechanism,
The optical scanning device according to claim 1, wherein the protrusion also serves as the posture holding protrusion. On the bottom surface of the housing body, there is provided a fastening portion for fastening a screw for fixing the housing body on the body frame of the image forming apparatus body,
3. The optical scanning device according to claim 1, wherein a protruding height of the positioning boss with respect to the bottom surface of the housing body is larger than a protruding height of the fastening portion with respect to the bottom surface of the housing body.   An image forming apparatus comprising: the optical scanning device according to claim 1; and a main body frame on which the optical scanning device is placed. An optical scanning device according to claim 2, and a main body frame on which the optical scanning device is placed,
The housing is provided with a cooling duct through which an air flow for cooling the polygon motor passes,
The main body frame is provided with a first opening hole into which the protruding portion is fitted,
The image forming apparatus according to claim 1, wherein the first opening hole is formed so that an air flow can pass in a state in which the protruding portion is fitted, and the first opening hole communicates with the cooling duct. The bottom surface of the housing body is provided with a second opening hole into which the posture holding projection is fitted,
The image forming apparatus according to claim 4, wherein the second opening hole is provided with a vibration isolating member that contacts the posture holding protrusion.

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