JP2017125963A - Optical scanner and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner that can be reduced in height, and an image forming apparatus.SOLUTION: In an optical scanner 6, a first reflection part 77 includes a reflection surface 77A that is inclined downward in the horizontal direction with respect to the axis and inclined in the vertical direction with respect to the axis, and reflects a plurality of laser beams emitted from a plurality of light sources 72. A second reflection part 63 is provided corresponding to the plurality of laser beams, and reflects the laser beams after passing through the first scanning lens 65 upward respectively toward a plurality of image carriers. A third reflection part 64 is arranged below the second reflection part 63, and reflects the laser beams after passing through the first scanning lens 65 toward the second reflection part 63.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical scanning device that scans a laser beam and an image forming apparatus.

  An electrophotographic image forming apparatus corresponding to a color forms an electrostatic latent image based on image data on each image carrier by causing a plurality of laser beams corresponding to each color to scan the image carrier corresponding to each color. An optical scanning device is provided (see, for example, Patent Document 1). This type of optical scanning device includes an optical scanning member that scans a plurality of laser beams emitted from a plurality of light sources, and an optical member that guides a plurality of laser beams scanned by the optical scanning member to a plurality of image carriers. Is provided. The optical member includes a reflection mirror, a scanning lens, and the like that are arranged on an incident path of each laser beam to each image carrier.

JP 2006-184750 A

  By the way, the size of the optical scanning device in the height direction may be determined by the arrangement structure of the reflection mirror and the scanning lens included in the optical member. Specifically, the optical scanning device includes a folding mirror that reflects the laser light that has passed through the scanning lens, and an output mirror that reflects the laser light reflected by the folding mirror toward the image carrier disposed above. And may be provided. In this case, the size in the height direction of the optical scanning device may be determined by the vertical relationship between the folding mirror and the output mirror. In particular, in a configuration in which laser light is reflected upward in the scanning member in the optical scanning device, in order to avoid the interference between the reflection mirror and the scanning lens and the path of the laser light, the reflection mirror and the scanning lens are arranged. Reduction in the height of the optical scanning device may be hindered.

  An object of the present invention is to provide an optical scanning apparatus and an image forming apparatus capable of realizing a low profile.

  An optical scanning device according to one aspect of the present invention includes a plurality of light sources, a first reflecting unit, a scanning member, a scanning lens, a second reflecting unit, and a third reflecting unit. The plurality of light sources emit laser light. The first reflecting section has a reflecting surface that is inclined downward with the horizontal direction as an axis and inclined with the vertical direction as an axis, and reflects the plurality of laser beams emitted from the plurality of light sources. The scanning member has a deflection surface parallel to the vertical direction, and reflects and scans the plurality of laser beams reflected by the first reflecting portion and incident on the deflection surface. The scanning lens is disposed in a posture in which an optical axis descends along the traveling direction of the laser light, and is used for imaging a plurality of the laser light scanned by the scanning member. The second reflection unit is provided corresponding to the plurality of laser beams, and reflects the laser beam after passing through the scanning lens upward toward each of the plurality of image carriers. The third reflection unit is disposed below the second reflection unit and reflects the laser light after passing through the scanning lens toward the second reflection unit.

  An image forming apparatus according to another aspect of the present invention includes the optical scanning device and a plurality of the image carriers on which electrostatic latent images are formed by the plurality of laser beams emitted from the optical scanning device. .

  According to the present invention, an optical scanning device and an image forming apparatus capable of realizing a low profile are provided.

FIG. 1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view of the light source unit of the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a plan view of the light source unit of the image forming apparatus according to the embodiment of the present invention. 4 is a cross-sectional view taken along the line IV-IV in FIG. FIG. 5 is a conceptual diagram schematically showing a path of laser light in the optical scanning device according to the embodiment of the present invention. FIG. 6 is a conceptual diagram schematically showing a laser beam path in the optical scanning device according to the embodiment of the present invention. FIG. 7 is a conceptual diagram schematically showing the path of laser light in the optical scanning device according to the comparative example. FIG. 8 is a conceptual diagram schematically showing a path of laser light in the optical scanning device according to the comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the following embodiment is an example which actualized this invention, Comprising: It does not have the character which limits the technical scope of this invention. Moreover, it may be described by using the up / down / left / right or front / rear directions defined in the attached drawings.

  First, a schematic configuration of the image forming apparatus 10 according to the embodiment of the present invention will be described.

  As shown in FIG. 1, the image forming apparatus 10 includes a plurality of image forming units 1 to 4, an intermediate transfer belt 5, an optical scanning device 6, a secondary transfer roller 7, a fixing device 8, a paper discharge tray 9, and paper feed. The color printer includes a cassette 21 and a conveyance path 22. The image forming apparatus 10 forms a monochrome image or a color image on a sheet such as paper based on input image data. The image forming apparatus according to the present invention may be, for example, a facsimile machine, a copier, or a multifunction machine.

  Each of the image forming units 1 to 4 is an electrophotographic image forming unit including a photosensitive drum (image carrier), a charging device, a developing device, a primary transfer roller, and a cleaning device. The image forming units 1 to 4 are juxtaposed along the traveling direction of the intermediate transfer belt 5 and constitute a so-called tandem image forming unit. Specifically, toner images corresponding to C (cyan) in the image forming unit 1, M (magenta) in the image forming unit 2, Y (yellow) in the image forming unit 3, and K (black) in the image forming unit 4 are formed. Is done. The developing devices of the image forming units 1 to 4 are supplied with toner (developer) of each color from the toner containers 11 to 14. The intermediate transfer belt 5 is an intermediate transfer member to which toner images of respective colors formed on the photosensitive drums of the image forming units 1 to 4 are transferred in a superimposed manner. The toner image on the intermediate transfer belt 5 is transferred to the sheet supplied from the paper feed cassette 21 by the secondary transfer roller 7 and melted and fixed to the sheet by the fixing device 8.

  The optical scanning device 6 includes a light source unit 61, a polygon mirror 62, a second reflecting unit 63, a third reflecting unit 64, a first scanning lens 65, a second scanning lens 66, and the like. Then, the optical scanning device 6 scans the photosensitive drums of the image forming units 1 to 4 with the laser light emitted from the light source unit 61 based on the input image data of each color, thereby the photosensitive drums. An electrostatic latent image is formed on each.

  The light source unit 61 emits laser light corresponding to each of the image forming units 1 to 4. The polygon mirror 62 has a plurality of deflection surfaces 62A parallel to the vertical direction, and is a scanning member that is rotated by a predetermined drive motor. As a result, the polygon mirror 62 reflects a plurality of laser beams emitted from the light source unit 61 and incident on the deflecting surface 62A, and scans along the predetermined main scanning direction. For example, the polygon mirror 62 has six deflecting surfaces 62A having a regular hexagonal shape in plan view.

  Of the laser beams scanned by the polygon mirror 62, the laser beams corresponding to the image forming units 1 to 3 are guided to the second reflecting unit 63 through the first scanning lens 65, the third reflecting unit 64, and the second scanning lens 66. It is burned. On the other hand, laser light corresponding to the image forming unit 4 out of laser light scanned by the polygon mirror 62 is guided to the second reflecting portion 63 through the first scanning lens 65 and the second scanning lens 66.

  The second reflector 63 scans the polygon mirror 62 and then passes the first scanning lens 65 and the second scanning lens 66 toward the photosensitive drums of the image forming units 1 to 4. It is a reflection mirror that reflects upward. In particular, each of the second reflecting portions 63 is positioned such that the reflection position of each laser beam at the second reflecting portion 63 is at the same height as or above the reflection position of each laser beam at the deflecting surface 62A of the polygon mirror 62. Are arranged to be. The image forming unit 3 is provided with two second reflecting portions 63, and the two second reflecting portions 63 pass through the first scanning lens 65 and the second scanning lens 66 and then the laser light. Is configured to reflect upward toward the photosensitive drum. Of the two second reflecting parts 63 corresponding to the image forming unit 3, only the second reflecting part 63 on the downstream side in the laser beam passage path may be regarded as the second reflecting part.

  The third reflecting portion 64 is a reflecting mirror disposed below the second reflecting portion 63. Then, the third reflection unit 64 reflects the laser light after passing through the first scanning lens 65 toward the second reflection unit 63 after being scanned by the polygon mirror 62. In particular, each of the third reflecting portions 64 is positioned such that the reflection position of each laser beam at the third reflecting portion 64 is at the same height as or below the reflection position of each laser beam at the deflection surface 62A of the polygon mirror 62. Are arranged to be.

  The first scanning lens 65 is disposed on the downstream side of the polygon mirror 62 in the traveling direction of the laser beam, and is also used as a scanning lens for a plurality of laser beams. On the other hand, the second scanning lens 66 is provided corresponding to each laser beam. Specifically, the second scanning lens 66 corresponding to the image forming units 1 to 3 is disposed between the third reflecting portion 64 and the second reflecting portion 63, and the second scanning lens corresponding to the image forming unit 4. The lens 66 is disposed between the first scanning lens 65 and the second reflecting portion 63. In the optical scanning device 6, each laser beam scanned by the polygon mirror 62 is imaged on each photosensitive drum by the first scanning lens 65 and the second scanning lens 66.

  Next, the light source unit 61 mounted on the optical scanning device 6 will be described with reference to FIGS.

  As shown in FIGS. 2 to 4, the light source unit 61 includes a support body 70, a substrate 71, a light source 72, a collimator lens 73, an aperture 74, a reflection mirror 75, a cylindrical lens 76, a first reflection unit 77, and the like. Prepare. A light source 72, a collimator lens 73, an aperture 74, and a reflection mirror 75 are provided for each of the photosensitive drums of the image forming units 1 to 4. On the other hand, the cylindrical lens 76 and the first reflecting portion 77 are common to the plurality of photosensitive drums.

  Each of the light sources 72 is a semiconductor laser element that emits laser light, and is mounted on the substrate 71. The light source 72 is a single beam light source that emits one laser beam or a monolithic multi-beam light source that can emit a plurality of laser beams. Each of the collimator lenses 73 converts the laser light emitted from each of the light sources 72 into parallel light. Each aperture 74 has an opening that limits the optical path width of the laser light after passing through each collimator lens 73. The aperture 74 has a rectangular or elliptical shape whose longitudinal direction is parallel to the left-right direction.

  Each of the reflection mirrors 75 reflects the laser light emitted from the light source 72 and passed through the collimator lens 73 and the aperture 74 toward the cylindrical lens 76. The cylindrical lens 76 converges each of the laser beams to form a line image on the deflection surface 62A of the polygon mirror 62. The first reflecting portion 77 is a reflecting mirror having a reflecting surface 77 </ b> A that reflects each laser beam after passing through the cylindrical lens 76 toward the polygon mirror 62.

  By the way, the size of the optical scanning device 6 in the height direction may be determined by the arrangement structure of the second reflecting portion 63, the third reflecting portion 64, the second scanning lens 66, and the like. Specifically, the size of the optical scanning device 6 in the height direction may be determined depending on the vertical relationship between the third reflection unit 64 and the second reflection unit 63. In particular, in the configuration in which the laser beam is reflected upward by the polygon mirror 62 in the optical scanning device 6, the second reflection unit 63, the third reflection unit 64, the second scanning lens 67, and the reflection path of the laser beam. In order to avoid the interference and arrange the second reflection unit 63, the third reflection unit 64, the second scanning lens 67, and the like, a reduction in the height of the optical scanning device 6 may be hindered. In contrast, in the optical scanning device 6 of the image forming apparatus 10 according to the present embodiment, it is possible to reduce the height of the optical scanning device 6.

  FIG. 5 and FIG. 6 are conceptual diagrams schematically showing laser beam paths in the optical scanning device 6 according to this embodiment. As shown in FIG. 5, in the optical scanning device 6, the reflecting surface 77 </ b> A of the first reflecting portion 77 of the light source unit 61 is disposed in a state inclined downward by a predetermined angle with respect to the horizontal direction as an axis. ing. In addition, the reflection surface 77A of the first reflection unit 77 is arranged in a state inclined by a predetermined angle with the vertical direction as an axis, and the plurality of reflection surfaces 77A after being irradiated from the plurality of light sources 72 and reflected by the reflection mirror 75. Are reflected toward the polygon mirror 62.

  In the optical scanning device 6 configured as described above, the first reflecting unit 77 reflects each laser beam irradiated from each of the light sources 72 and passing through the cylindrical lens 76 in a manner of dropping downward. Become. Note that the reference position P11 indicated by the one-dot chain line in FIG. 5 is a line segment that passes through the reflection position of the laser beam on the deflection surface 62A of the polygon mirror 62 and is parallel to the horizontal direction.

  As shown in FIG. 5, each of the laser beams emitted from the light source 72 is incident on the deflection surface 62A of the polygon mirror 62 while being inclined from above, reflected by the deflection surface 62A, and emitted downward. The Note that the light source 72 disposed at the lowermost position among the plurality of light sources 72 may be incident and emitted horizontally with respect to the deflection surface 62 </ b> A of the polygon mirror 62.

  In the optical scanning device 6, the incident position of the laser beam on the deflecting surface 62 </ b> A of the polygon mirror 62 is positioned below the reflecting position of the laser beam on the reflecting surface 77 </ b> A of the first reflecting portion 77 of the light source unit 61. A light source unit 61 and a polygon mirror 62 are arranged. As a result, the laser light reflected by the first reflecting portion 77 descends toward the deflection surface 62A of the polygon mirror 62 along the traveling direction thereof and enters the deflection surface 62A.

  On the other hand, as shown in FIG. 6, in the optical scanning device 6, the third reflecting portion 64 is arranged corresponding to each laser beam emitted horizontally or downward from the deflection surface 62 </ b> A of the polygon mirror 62. . That is, each of the third reflecting portions 64 is in a state where the incident position of the laser light in each of the third reflecting portions 64 is the same as or lower than the reflecting position of the laser light on the deflection surface 62A of the polygon mirror 62. Is arranged in. In FIG. 6, the upper position P12 is the upper end position of optical components such as the second reflecting section 63, the third reflecting section 64, the first scanning lens 65, and the second scanning lens 66, and the lower position P13 is This is the lower end position of optical components such as the second reflecting portion 63, the third reflecting portion 64, the first scanning lens 65, and the second scanning lens 66.

  Then, in the optical scanning device 6, the remaining 4 is in the region above the reference position P 11 and avoiding interference with the laser beam incident path from the polygon mirror 62 to the second reflecting portion 63 or the third reflecting portion 64. Two second reflecting parts 63, a second scanning lens 66, and the like are arranged. Thereby, in the optical scanning device 6, the size in the height direction is suppressed, and a reduction in height can be realized. More specifically, in the optical scanning device 6, the second reflecting portion 63 and the second scanning lens 66 are laser-laminated in a direction to be launched from the polygon mirror 62 toward the second reflecting portion 63 or the third reflecting portion 64 as will be described later. It is possible to dispose it below the structure that reflects light.

  FIG. 7 and FIG. 8 are diagrams showing a configuration of a comparative example of the optical scanning device 6. In the light source unit 61 shown in FIG. 7, the reflecting surface 77 </ b> A of the first reflecting portion 77 of the light source unit 61 is arranged in parallel to the vertical direction without being inclined. 7 is a line segment that passes through the laser beam reflection position on the deflection surface 62A of the polygon mirror 62 and is parallel to the horizontal direction. In the optical scanning device 6 configured in this way, the laser light emitted from the two light sources 72 arranged on the upper side of the four light sources 72 passes through the cylindrical lens 76 and then is lowered by the first reflecting unit 77. Reflects in a manner that it is downed toward.

  On the other hand, the laser light emitted from the two light sources 72 arranged on the lower side of the four light sources 72 is reflected by the first reflecting portion 77 so as to be launched upward after passing through the cylindrical lens 76. That is, the laser light emitted from the light source 72 is incident on the deflecting surface 62A of the polygon mirror 62 while being inclined from below, reflected by the deflecting surface 62A, and emitted upward.

  Therefore, in order to avoid the interference with the incident path of the laser beam from the polygon mirror 62 to the second reflecting portion 64 or the third reflecting portion 63, the second reflecting portion 63 or the third reflecting portion from the polygon mirror 62 is arranged. Compared to the configuration in which the laser beam is reflected in the direction of dropping toward 64, it is necessary to arrange the second reflecting portion 63 and the second scanning lens 66 upward, and the reduction in the height of the optical scanning device 6 is hindered. . Specifically, in FIG. 8, the upper position P22 is an upper end position of optical components such as the second reflecting portion 63, the third reflecting portion 64, the first scanning lens 65, and the second scanning lens 66, and the upper position P12. It can be seen that it is located higher than (see FIG. 6).

  By the way, in the present embodiment, the configuration in which the cylindrical lens 76 is disposed between the reflection mirror 75 and the first reflection unit 77 has been described as an example. On the other hand, a configuration in which the cylindrical lens 76 is disposed between the first reflecting portion 77 and the polygon mirror 62 in the traveling direction of the laser light is also conceivable as another embodiment.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 6 Optical scanning device 61 Light source unit 62 Polygon mirror 62A Deflection surface 63 2nd reflection part 64 3rd reflection part 65 1st scanning lens 66 2nd scanning lens 70 Support body 71 Board | substrate 72 Light source 73 Collimator lens 74 Aperture 75 Reflective mirror 76 Cylindrical lens 77 First reflective portion 77A Reflective surface

Claims (5)

A plurality of light sources that emit laser light;
A first reflecting portion that has a reflecting surface that is inclined downward with respect to the horizontal direction as an axis and that is inclined with respect to the vertical direction as an axis, and that reflects the plurality of laser beams emitted from the plurality of light sources;
A scanning member that has a deflection surface parallel to the vertical direction, and reflects and scans the plurality of laser beams reflected by the first reflecting portion and incident on the deflection surface;
A scanning lens that is arranged in a posture in which an optical axis descends along the traveling direction of the laser light, and is used for imaging a plurality of the laser light scanned by the scanning member;
A second reflecting portion provided corresponding to the plurality of laser beams, and reflecting the laser beams after passing through the scanning lens upward toward the plurality of image carriers,
A third reflecting portion that is disposed below the second reflecting portion and reflects the laser light after passing through the scanning lens toward the second reflecting portion;
An optical scanning device comprising: The scanning lens as a first scanning lens,
A second scanning lens that is disposed between the first scanning lens and the second reflecting portion corresponding to each laser beam and is used for imaging the laser beam;
The optical scanning device according to claim 1, wherein each of the laser beams is focused on each of the image carriers by the first scanning lens and the second scanning lens.   The optical scanning device according to claim 2, wherein the second scanning lens corresponding to one or a plurality of the laser beams is disposed between the third reflection unit and the second reflection unit. A reflection position of each of the laser beams in each of the third reflection portions is positioned below a reflection position of each of the laser beams on the deflection surface of the scanning member;
4. The reflection position of each of the laser beams in each of the second reflection units is located at the same height position as or above the reflection position of each of the laser beams on the deflection surface of the scanning member. Optical scanning device. An optical scanning device according to any one of claims 1 to 4,
A plurality of image carriers on which electrostatic latent images are formed by the plurality of laser beams emitted from the optical scanning device;
An image forming apparatus comprising:

Images