Optical scanning device and image formation apparatus including the same

Abstract

To provide an optical scanning device in which a light-emitting module can be easily adjusted in position and fixed, and an image formation apparatus including the same.SOLUTION: An optical scanning device includes a light source part, a polygon mirror, a first scanning lens, a second scanning lens, and a housing part. The light source part comprises multiple light-emitting modules that emit laser light. The housing part stores the light source part, the polygon mirror, the first scanning lens, and the second scanning lens. Each light-emitting module includes a light-emitting element that emits laser light, a coupling lens, and a bracket. The coupling lens converts the laser light emitted from the light-emitting element into the light in substantially-parallel in a main scanning direction and focuses it in a sub-scanning direction. The light-emitting modules are arranged so as to be arrayed in a vertical direction between adjacent protrusion parts, and the bracket is fixed to the protrusion parts on both sides via an adhesive.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an optical scanning device that forms a latent image on a scanned surface by exposure scanning, and to an image forming apparatus equipped with the same, such as a copying machine, a printer, a facsimile, or a combination machine thereof. [Background technology]

[0002] A conventional optical scanning device is disclosed in Patent Document 1. This optical scanning device has a light source unit, a polygon mirror, a first scanning lens, a second scanning lens, and a storage unit (optical box). The light source unit has a plurality of light emitting modules (optical units) that emit laser light arranged therein. The polygon mirror rotates around a rotation axis extending in the vertical direction to reflect the laser light emitted from the light source unit and scan the peripheral surface of the image carrier in the main scanning direction. The first scanning lens collects the laser light reflected by the polygon mirror. The second scanning lens forms an image of the laser light that has passed through the first scanning lens on the peripheral surface of the image carrier. The storage unit houses the light source unit, the polygon mirror, the first scanning lens, and the second scanning lens.

[0003] The light emitting module has a light emitting element, a lens, and a bracket. The light emitting element emits laser light. The lens converts the laser light emitted from the light emitting element to be approximately parallel to the main scanning direction. The bracket is formed in a cylindrical shape, extends in the emission direction of the laser light, and holds the lens therein. The two light emitting modules are unitized via a fixing member, and the fixing member is fixed to the housing part. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2004-0377836 A Summary of the Invention [Problem to be solved by the invention]

[0005] With the conventional optical scanning device described above, when adjusting and fixing the position of the light-emitting module, there was a problem in that it was difficult to adjust the position by rotating the light-emitting module in a circumferential direction around the emission direction of the laser light or tilting it vertically.

[0006] In view of the above problems, an object of the present invention is to provide an optical scanning device in which the position of a light emitting module can be easily adjusted and fixed, and an image forming apparatus including the same. [Means for solving the problem]

[0007] In order to achieve the above object, a first configuration of the present invention is an optical scanning device including a light source unit, a polygon mirror, a first scanning lens, a second scanning lens, and a storage unit. The light source unit has a plurality of light emitting modules that emit laser light. The polygon mirror rotates around a rotation axis extending in the vertical direction to reflect the laser light emitted from the light source unit and scans the peripheral surface of the image carrier in the main scanning direction. The first scanning lens collects the laser light reflected by the polygon mirror. The second scanning lens forms an image of the laser light that has passed through the first scanning lens on the peripheral surface of the image carrier. The storage unit stores the light source unit, the polygon mirror, the first scanning lens, and the second scanning lens. The light emitting module has a light emitting element that emits laser light, a coupling lens, and a bracket. The coupling lens converts the laser light emitted from the light emitting element to be approximately parallel to the main scanning direction and collects it in the sub-scanning direction. The bracket is cylindrical, and extends in the direction in which the laser light is emitted to hold the coupling lens therein. The housing has a bottom wall and a plurality of protrusions. The bottom wall extends in a direction perpendicular to the rotation axis. The protrusions protrude upward from an upper surface of the bottom wall. The light emitting modules are arranged in a vertical line between adjacent protrusions, and brackets are fixed to the protrusions on both sides with an adhesive. Effect of the Invention

[0008] According to the first configuration of the present invention, it is possible to provide an optical scanning device in which the position of a light emitting module can be easily adjusted and fixed, and an image forming apparatus including the same. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the overall configuration of an image forming apparatus 100 equipped with an optical scanning device 5 according to the present invention. [Diagram 2] FIG. 1 is a perspective view of an optical scanning device 5 according to an embodiment of the present invention. [Diagram 3] FIG. 1 is a perspective view of an optical scanning device 5 according to an embodiment of the present invention. [Figure 4] Cross section taken along the line AA in Figure 2 [Diagram 5] FIG. 2 is an enlarged perspective view showing the vicinity of a light source unit 46 of the optical scanning device 5 of the present invention. [Figure 6] FIG. 1 is a perspective view of light-emitting modules 30K and 30Y of an optical scanning device 5 according to the present invention; [Figure 7] FIG. 1 is a perspective view of light-emitting modules 30C and 30M of an optical scanning device 5 according to the present invention; [Figure 8] 1 is a side cross-sectional view of light-emitting modules 30K and 30Y of an optical scanning device 5 according to the present invention; [Figure 9] 1 is a side cross-sectional view of light-emitting modules 30C and 30M of an optical scanning device 5 according to the present invention; [Figure 10] 1 is a cross-sectional view perpendicular to the main scanning direction of a light source unit 46 of an optical scanning device 5 according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [1. Configuration of image forming apparatus 100] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the overall configuration of an image forming apparatus 100 in which an optical scanning device 5 of the present invention is mounted. For convenience of explanation, the vertical direction in an installation state (as shown in FIG. 1) in which the image forming apparatus 100 can be used is defined as the up-down direction (Z1-Z2 direction). In addition, the front side of the paper of the image forming apparatus 100 shown in FIG. 1 is defined as the front (front face) and the front-rear direction (Y1-Y2 direction) is defined. In addition, the left-right direction (X1-X2 direction) is defined with the front face of the image forming apparatus 100 in the installation state as a reference. In this embodiment, the left-right direction (X1-X2 direction) is perpendicular to the up-down direction (Z1-Z2 direction) and the front-rear direction (Y1-Y2 direction).

[0011] The image forming apparatus 100 is a tandem type color printer. The image forming apparatus 100 includes rotatable photoconductor drums 1a to 1d as image carriers. For the photoconductor drums 1a to 1d, an organic photoconductor (OPC photoconductor) having an organic photosensitive layer formed thereon, or an amorphous silicon photoconductor having an amorphous silicon photosensitive layer formed thereon, or the like, is used. The photoconductor drums 1a to 1d are arranged in tandem corresponding to the respective colors of yellow, cyan, magenta, and black.

[0012] Around the photoconductor drum 1a, a developing device 3a, a charger 2a, and a cleaning device 7a are disposed. Similarly, around the photoconductor drums 1b to 1d, developing devices 3b to 3d, chargers 2b to 2d, and cleaning devices 7b to 7d are disposed, respectively. In addition, an optical scanning device 5 is disposed above Z1 the developing devices 3a to 3d.

[0013] The developing devices 3a to 3d are disposed on the right side X1 of the photoconductor drums 1a to 1d, respectively. The developing devices 3a to 3d face the photoconductor drums 1a to 1d, respectively, and supply toner to the photoconductor drums 1a to 1d. The developing devices 3a to 3d have containers 4a to 4d, which contain magenta, cyan, yellow, and black toner, respectively.

[0014] The chargers 2a to 2d are disposed upstream of the developing devices 3a to 3d in the rotation direction of the photoconductor drums 1a to 1d and face the surfaces of the photoconductor drums 1a to 1d, respectively. The chargers 2a to 2d uniformly charge the surfaces of the photoconductor drums 1a to 1d, respectively.

[0015] In this embodiment, the optical scanning device 5 is disposed above the photoconductor drums 1a-1d at Z1. The optical scanning device 5 irradiates light (optical scanning) onto the surfaces of the photoconductor drums 1a-1d uniformly charged by the chargers 2a-2d based on image data such as characters and patterns input to an image input unit from a personal computer or the like. As a result, electrostatic latent images are formed on the surfaces of the photoconductor drums 1a-1d.

[0016] The housing 48 of the optical scanning device 5 is a resin molded product, and includes a storage section 481 having an opening on one surface (the upper surface in this embodiment) and a lid section 482 that covers the opening (see FIG. 4). The storage section 481 stores the scanning optical system therein. The storage section 48 will be described in detail later.

[0017] The laser beams D1-D4 are irradiated onto the surfaces of the photoconductor drums 1a-1d from downstream of the chargers 2a-2d in the direction of rotation of the photoconductor drums 1a-1d, respectively. As a result, electrostatic latent images are formed on the surfaces of the photoconductor drums 1a-1d. These electrostatic latent images are developed into toner images by the developing devices 3a-3d. The optical scanning device 5 will be described in detail later.

[0018] An endless intermediate transfer belt 8 is stretched around a drive roller 10 and a driven roller 11. When the drive roller 10 is rotated by a motor (not shown), the intermediate transfer belt 8 is driven to circulate in the clockwise direction in FIG.

[0019] The photoconductor drums 1a to 1d are arranged adjacent to each other along the transport direction (the direction of the arrow in FIG. 1) above the intermediate transfer belt 8. The photoconductor drums 1a to 1d are in contact with the intermediate transfer belt 8, respectively.

[0020] The primary transfer rollers 6a to 6d face the photoconductor drums 1a to 1d, respectively, with the intermediate transfer belt 8 therebetween. The primary transfer rollers 6a to 6d are pressed against the intermediate transfer belt 8, respectively, and form primary transfer portions together with the photoconductor drums 1a to 1d. In these primary transfer portions, toner images are transferred to the intermediate transfer belt 8.

[0021] Specifically, a primary transfer voltage is applied to the primary transfer rollers 6a to 6d, so that the toner images on the photoconductor drums 1a to 1d are transferred sequentially at a predetermined timing onto the intermediate transfer belt 8. As a result, a full-color toner image is formed on the surface of the intermediate transfer belt 8, in which toner images of four colors, magenta, cyan, yellow, and black, are superimposed in a predetermined positional relationship.

[0022] The secondary transfer roller 9 faces the drive roller 10 with the intermediate transfer belt 8 sandwiched therebetween. The secondary transfer roller 9 is pressed against the intermediate transfer belt 8 and forms a secondary transfer section together with the drive roller 10. In this secondary transfer section, a secondary transfer voltage is applied to the secondary transfer roller 9, so that the toner image on the surface of the intermediate transfer belt 8 is transferred to the paper S. After the toner image is transferred, a belt cleaning device (not shown) cleans off any toner remaining on the intermediate transfer belt 8.

[0023] A paper feed cassette 16 is disposed at the bottom inside the image forming apparatus 100. The paper feed cassette 16 is capable of storing a plurality of sheets of paper S. To the right X1 of the paper feed cassette 16, a paper transport path 19 is disposed.

[0024] The paper transport path 19 transports the paper S fed from the paper feed cassette 16 to the secondary transfer unit. A fixing unit 13 and a paper transport path 20 are disposed in the upper right corner of the image forming apparatus 100. The fixing unit 13 performs a fixing process on the paper S on which an image has been formed. The paper transport path 20 transports the paper S which has been subjected to the fixing process to the paper discharge unit 17.

[0025] The sheets S stored in the paper feed cassette 16 are fed one by one to the paper transport path 19 side by the pickup roller 12a.

[0026] The pair of registration rollers 12b transports the paper S to the secondary transfer section in accordance with the timing of the image forming operation on the intermediate transfer belt 8 and the paper feeding operation to the secondary transfer section. The full-color toner image on the intermediate transfer belt 8 is secondarily transferred onto the paper S transported to the secondary transfer section by a secondary transfer roller 9 to which a secondary transfer voltage is applied. The paper S to which the full-color toner image has been transferred is transported to a fixing section 13.

[0027] The fixing unit 13 includes a fixing belt heated by a heater, a fixing roller in contact with the fixing belt, and a pressure roller pressed against the fixing roller with the fixing belt sandwiched therebetween. The fixing unit 13 heats and presses the paper S onto which the toner image has been transferred. This performs the fixing process. The paper S onto which the toner image has been fixed in the fixing unit 13 is turned over in the paper transport path 18 as necessary. The paper S is then transported again to the secondary transfer unit via the pair of registration rollers 12b, after which a new toner image is secondarily transferred onto the rear surface of the paper S by the secondary transfer roller 9, and fixed in the fixing unit 13. The paper S onto which the toner image has been fixed passes through the paper transport path 20 and is discharged to the paper discharge unit 17.

[0028] [2. Configuration of optical scanning device] 2 and 3 are perspective views of the optical scanning device 5, and FIG. 3 shows a state in which the cover 482 is removed. FIG. 4 is a cross-sectional view taken along line AA in FIG. 2. A part of FIG. 4 shows the configuration of each member in a schematic manner, and does not strictly show the shape and positional relationship of each member. Also, FIG. 4 does not show the first scanning lens 41 and the second scanning lens 42.

[0029] In the following description, the main scanning direction (Y1-Y2 direction) is the longitudinal direction of the reflecting mirrors 49a to 49c. The main scanning direction (Y1-Y2 direction) coincides with the direction in which the rotation axes of the photosensitive drums 1a to 1d extend and with the front-rear direction of the image forming apparatus 100. The sub-scanning direction (Z1-Z2 direction) is parallel to the rotation axis J of the polygon mirror 45 and coincides with the up-down direction of the image forming apparatus 100. The left-right direction (X1-X2 direction) is perpendicular to the main scanning direction (Y1-Y2 direction) and the sub-scanning direction (Z1-Z2 direction), and coincides with the juxtaposition direction of the reflecting mirrors 49a to 49c.

[0030] The optical scanning device 5 outputs (irradiates) multiple (four in this embodiment) laser beams D1 to D4 modulated according to each image signal onto the photosensitive drums 1a to 1d, exposing the surfaces of the photosensitive drums 1a to 1d to form electrostatic latent images with attenuated charge.

[0031] The optical scanning device 5 includes a light source unit 46, a polygon mirror 45, a pair of first scanning lenses 41, a pair of second scanning lenses 42, a pair of reflecting mirrors 49a, 49b, 49c, and a housing 48 (a housing portion 481).

[0032] The housing 48 includes a storage section 481 and a cover section 482. The storage section 481 is formed in a substantially rectangular shape when viewed from above. The storage section 481 stores the light source section 46, the polygon mirror 45, a pair of first scanning lenses 41, a pair of second scanning lenses 42, and a pair of reflecting mirrors 49a, 49b, and 49c.

[0033] The storage section 481 has a bottom wall section 481a, a peripheral wall section 481b, and a plurality of protrusions 90, 91, and 92. The bottom wall section 481a expands in a direction perpendicular to the rotation axis J of the polygon mirror 45. The bottom wall section 481a is formed with emission openings 483a to 483d penetrating in the up-down direction (see FIG. 4). The emission openings 483a to 483d extend in the main scanning direction (Y1-Y2 direction). The laser beams D1 to D4 emitted from the scanning optical system are emitted to the outside of the housing 48 through the emission openings 483a to 483d and enter the corresponding photoconductor drums 1a to 1d, respectively. The emission openings 483a to 483d are covered with dustproof glasses 70a to 70d, respectively. This makes it possible to prevent dust from entering the inside of the housing 48.

[0034] The protrusions 90, 91, and 92 protrude upward from the upper surface of the bottom wall portion 481a. The protrusions 90, 91, and 92 support the light source unit 46. The shapes of the protrusions 90, 91, and 92 will be described in detail later.

[0035] The peripheral wall portion 481b extends upward from the outer periphery of the bottom wall portion 481a and laterally surrounds the light source unit 46, the polygon mirror 45, the pair of first scanning lenses 41, the pair of second scanning lenses 42, and the pair of reflecting mirrors 49a, 49b, 49c inside.

[0036] The lid portion 482 has a top surface portion 482a and a peripheral surface portion 482b. The top surface portion 482a covers the open upper surface of the storage portion 481. The peripheral surface portion 482b extends downward from the outer periphery of the top surface portion 482a and covers a part of the peripheral wall portion 481b from the radially outer side.

[0037] The light source unit 46 has a plurality of light emitting modules 30Y, 30C, 30M, and 30K that emit laser light. The light emitting modules 30Y, 30C, 30M, and 30K output laser light D1 to D4 corresponding to the colors Y (yellow), C (cyan), M (magenta), and K (black), respectively. The laser light D1 to D4 emitted from each of the light emitting modules 30Y, 30C, 30M, and 30K is irradiated onto a polygon mirror 45. The laser light D1 to D4 forms a line image near the deflection surface of the polygon mirror 45.

[0038] Polygon mirror 45 rotates around rotation axis J extending in the vertical direction (Z1-Z2 direction) to reflect laser beams D1 to D4 emitted from light source unit 46, and scans the peripheral surfaces of photosensitive drums (image carriers) 1a to 1d in the main scanning direction.

[0039] The polygon mirror 45 is composed of a plurality of reflecting surfaces. In this embodiment, the polygon mirror 45 is a polygonal mirror formed in a quadrangular prism shape. The laser beams D1 and D2 incident on the polygon mirror 45 are deflected and scanned by any reflecting surface that rotates, reflected in the left direction (X2 direction) by the reflecting surface of the polygon mirror 45, and guided to the first scanning lens 41 and the second scanning lens 42. On the other hand, the laser beams D3 and D4 incident on the polygon mirror 45 are deflected and scanned by any reflecting surface that rotates, reflected in the right direction (X1 direction) by the reflecting surface of the polygon mirror 45, and guided to the first scanning lens 41 and the second scanning lens 42 (see FIG. 4).

[0040] The second scanning lens 42 is disposed downstream of the first scanning lens 41 in the optical paths of the laser beams D1 to D4.

[0041] The first scanning lens 41 is a lens having distortion (fθ characteristics) and is a long lens extending along the main scanning direction (Y1-Y2 direction). The first scanning lens 41 collects the laser beams D1 to D4 reflected by the deflection surface of the polygon mirror 45.

[0042] The second scanning lens 42 is a long lens that has distortion (fθ characteristics) and extends along the main scanning direction (Y1-Y2 direction) like the first scanning lens 41. The second scanning lens 42 collects the laser beams D1 to D4 that have passed through the first scanning lens 41, and forms images on the scanned surfaces of the photosensitive drums 1a to 1d, respectively.

[0043] The pair of reflecting mirrors 49a reflect the laser beams D1 and D4, respectively. The pair of reflecting mirrors 49b and the pair of reflecting mirrors 49c reflect the laser beams D2 and D3, respectively.

[0044] The laser light D1 collected by the first scanning lens 41 and the second scanning lens 42 is reflected by the reflecting mirror 49a and formed into an image on the scanned surface of the photosensitive drum 1a. The laser light D4 collected by the first scanning lens 41 and the second scanning lens 42 is reflected by the reflecting mirror 49a and formed into an image on the scanned surface of the photosensitive drum 1d.

[0045] The laser light D2 focused by the first scanning lens 41 and the second scanning lens 42 is reflected by the reflecting mirrors 49b and 49c to form an image on the scanned surface of the photosensitive drum 1b. The laser light D3 focused by the first scanning lens 41 and the second scanning lens 42 is reflected by the reflecting mirrors 49b and 49c to form an image on the scanned surface of the photosensitive drum 1c.

[0046] The laser beams D1 to D4 reflected and deflected by the polygon mirror 45 pass through the first scanning lens 41 and the second scanning lens 42 and are focused on the scanned surfaces of the photosensitive drums 1a to 1d, respectively. As a result, beam spots are formed on the scanned surfaces of the photosensitive drums 1a to 1d. The laser beams D1 to D4 focused on the scanned surfaces of the photosensitive drums 1a to 1d scan the scanned surfaces of the photosensitive drums 1a to 1d at a constant speed.

[0047] At this time, the laser beams D1 to D4 scan the scanned surfaces (circumferential surfaces) of the photoconductor drums (image carriers) 1a to 1d in the main scanning direction (Y1-Y2 direction) due to the rotation of the polygon mirror 45. Also, the laser beams D1 to D4 scan in the sub-scanning direction (Z1-Z2 direction) due to the rotation of the photoconductor drums 1a to 1d to form electrostatic latent images on the surfaces of the photoconductor drums 1a to 1d.

[0048] [3. Configuration of light source unit 46] Fig. 5 is an enlarged perspective view of light source unit 46, Fig. 6 is a perspective view of light emitting modules 30K and 30Y, and Fig. 7 is a perspective view of light emitting modules 30C and 30M, Fig. 8 is a side cross-sectional view of light emitting modules 30K and 30Y, and Fig. 9 is a side cross-sectional view of light emitting modules 30C and 30M.

[0049] The light source unit 46 is composed of light emitting modules 30Y, 30C, 30M, and 30K. The light emitting modules 30K and 30C are disposed to the right (X1 side) of the rotation axis J when viewed from the polygon mirror 45 in the main scanning direction (Y1-Y2 direction), and the light emitting module 30C is disposed below (Z2 side) the light emitting module 30K. The light emitting modules 30Y and 30M are disposed to the left (X2 side) of the rotation axis J when viewed from the polygon mirror 45 in the main scanning direction (Y1-Y2 direction), and the light emitting module 30M is disposed below (Z2 side) the light emitting module 30Y.

[0050] Among the light-emitting modules 30Y, 30C, 30M, and 30K, the light-emitting modules 30K and 30Y arranged on the upper side have the same shape and differ only in the color of the laser light emitted from the light-emitting element 35. Furthermore, the light-emitting modules 30C and 30M arranged on the lower side have the same shape and differ only in the color of the laser light emitted from the light-emitting element 35. Furthermore, the light-emitting modules 30K and 30Y and the light-emitting modules 30C and 30M differ only in the shape of the bracket 33.

[0051] The light-emitting modules 30Y, 30C, 30M, and 30K each have a light-emitting element 35 that emits any one of laser beams D1 to D4, a coupling lens 32, and a bracket 33. In this embodiment, the light-emitting element 35 of the light-emitting module 30K emits laser beam D1. The light-emitting element of the light-emitting module 30C emits laser beam D2. The light-emitting element 35 of the light-emitting module 30M emits laser beam D3. The light-emitting element 35 of the light-emitting module 30Y emits laser beam D4.

[0052] The coupling lens 32 converts each of the laser beams D1 to D4 emitted from the light emitting element 35 into beams approximately parallel to the main scanning direction and condenses the beams in the sub-scanning direction. As a result, the laser beams D1 to D4 form a line image in the vicinity of the deflection surface of the polygon mirror 45. For example, the coupling lens 32 has an anamorphic shape and is composed of a single lens molded by a metal mold.

[0053] Bracket 33 is cylindrical, extends in the emission direction of the laser light (direction A), and holds a coupling lens inside. Bracket 33 is composed of lens holder 331, laser holder 332, and element holder 333. Bracket 33 is a resin molded product, and a lightweight, heat-resistant synthetic resin (for example, an alloy material of ABS resin and PC resin) or the like is preferably used.

[0054] The laser holder 332 has a diaphragm section 34 extending in the emission direction (direction A) of the laser light and narrowing the optical path of the laser light therein. The diaphragm section 34 enables the laser light to obtain a desired beam spot diameter.

[0055] The lens holder 331 is fixed to one end of the laser holder 332 in the light emission direction (direction A), and holds the coupling lens 32 therein. The lens holder 331 also has an opening 331a, and the laser light that has passed through the coupling lens 32 is emitted to the outside of the bracket 33 through the opening 331a.

[0056] The element holder 333 is fixed to one end of the laser holder 332 in the light output direction (direction A), and holds the light emitting element 35 therein. The laser holder 332 and the element holder 333 are fixed to each other at predetermined positions via an adhesive, with their orientations changed three-dimensionally.

[0057] The laser holder 332 has a different shape between the light emitting modules 30Y and 30K and the light emitting modules 30C and 30M. That is, the laser holder 332 (bracket 33) of the light emitting modules 30K and 30Y arranged on the upper side among the light emitting modules 30Y, 30C, 30M, and 30K arranged in the vertical direction has an annular portion 332a. The annular portion 332a is formed in an annular shape protruding from the outer circumferential surface of the laser holder 332 (bracket 33). A plurality of the annular portions 332a are arranged in the emission direction of the laser light (direction A). By forming the annular portion 332a, it is possible to form the outermost diameter of the laser holder 332 (bracket 33) large while suppressing the occurrence of shrinkage cavities when the laser holder 332 (bracket 33) is resin molded.

[0058] By forming the annular portion 332a, the outermost diameter D2 of the laser holder 332 (bracket 33) of the light-emitting modules 30K and 30Y arranged on the upper side among the light-emitting modules 30Y, 30C, 30M, and 30K arranged side by side in the vertical direction is larger than the outermost diameter D1 of the laser holder 332 (bracket 33) of the light-emitting modules 30C and 30M arranged on the lower side (see FIG. 10). Note that the outermost diameters D1 and D2 are the outermost diameters in the region (region sandwiched between the protruding portions 90 and 91 or between the protruding portions 91 and 92) of the laser holder 332 (bracket 33) where the adhesive 95 described later is applied.

[0059] [4. How to fix the light emitting module] FIG. 10 is a cross-sectional view of the light source unit 46 perpendicular to the main scanning direction (Y1-Y2 direction). The bottom wall 481a of the housing unit 481 has protrusions 90, 91, and 92 protruding upward (Z1 direction) from the upper surface (see FIG. 6). In this embodiment, the protrusions 90, 91, and 92 have surfaces perpendicular to the left-right direction (X1-X2 direction) and are arranged side by side in the left-right direction (X1-X2 direction). When viewed from the polygon mirror 45 in the main scanning direction (Y1-Y2 direction), the protrusion 91 is arranged at a position overlapping with the rotation axis C, and the protrusion 90 is arranged to the left of the protrusion 91 (X2 direction). The protrusion 92 is arranged to the right of the protrusion 91 (X1 direction).

[0060] The light emitting modules 30Y, 30M are arranged side by side in the up-down direction (Z1-Z2 direction) between adjacent protrusions 90, 91, and the bracket 33 is fixed to the protrusions 90, 91 on both sides via an adhesive 95. The light emitting modules 30K, 30C are arranged side by side in the up-down direction (Z1-Z2 direction) between adjacent protrusions 91, 92, and the bracket 33 is fixed to the protrusions 91, 92 on both sides via an adhesive 95.

[0061] The adhesive 95 is made of, for example, an ultraviolet curing resin, which allows the light emitting modules 30Y, 30C, 30M, and 30K to be easily fixed to the protruding portions 90, 91, and 92 after being aligned.

[0062] Since the light emitting modules 30Y, 30C, 30M, and 30K are directly fixed to the protruding portions 90, 91, and 92 via the adhesive 95, the light emitting modules 30Y, 30C, 30M, and 30K can be easily fixed while adjusting their orientation. This allows the orientations of the laser beams D1 to D4 emitted from the light emitting modules 30Y, 30C, 30M, and 30K to be finely adjusted three-dimensionally in the left-right direction (X1-X2 direction), the front-back direction (Y1-Y2 direction), and the up-down direction (Z1-Z2 direction). This allows the positions of the optical axes of the laser beams D1 to D4 to be adjusted.

[0063] In addition, by moving the light emitting modules 30Y, 30C, 30M, and 30K in the front-back direction (Y1-Y2 direction) along the emission direction (A direction) of the laser beams D1 to D4, the focusing position on the deflection surface of the polygon mirror 45 in the sub-scanning direction can be adjusted.

[0064] Moreover, the optical axes of the laser beams D1 to D4 can be adjusted by rotating the light emitting modules 30Y, 30C, 30M, and 30K in the circumferential direction about the optical axes extending in the emission direction (direction A) of the laser beams D1 to D4.

[0065] The refractive index of the coupling lens 32 may vary due to temperature changes during molding, which may cause a shift in the focusing position on the deflection surface of the polygon mirror 45. In this case, the focusing position on the deflection surface of the polygon mirror 45 can be adjusted to an appropriate position by finely adjusting and fixing the positions and orientations of the light-emitting modules 30Y, 30C, 30M, and 30K. Therefore, the position of each of the light-emitting modules 30Y, 30C, 30M, and 30K can be easily adjusted and fixed to an appropriate position.

[0066] As described above, the laser holder 332 and the element holder 333 can be fixed to each other at a predetermined position via an adhesive while changing their orientation in three dimensions. This allows the positional relationship between the laser holder 332 and the element holder 333 to be adjusted before adjusting the orientations of the light-emitting modules 30Y, 30C, 30M, and 30K, so that the light-condensing position on the deflection surface of the polygon mirror 45 can be adjusted to an appropriate position.

[0067] The positions of the light-emitting modules 30Y, 30C, 30M, and 30K are adjusted by fixing the polygon mirror 45, the first scanning lens 41, the second scanning lens 42, and the reflecting mirrors 49a, 49b, and 49c in the housing 481, and checking, for example, the optical axis position and the beam diameter in the main scanning direction. This allows parallel light to be reliably incident on the first scanning lens 41, and the focusing position in the main scanning direction can be adjusted to an appropriate position. The positions of the light-emitting modules 30Y, 30C, 30M, and 30K may also be adjusted by checking with a camera the laser light focused on the surfaces of the photosensitive drums 1a to 1d.

[0068] The width L2 between the protrusions 90, 91 in the region sandwiching the light emitting module 30Y arranged on the upper side is larger than the width L2 between the protrusions 90, 91 in the region sandwiching the light emitting module 30M arranged on the lower side. Specifically, the maximum width L2 at the upper end between the protrusions 90, 91 to which the light emitting module 30K arranged on the upper side among the light emitting modules 30Y, 30C, 30M, and 30K arranged side by side in the vertical direction is fixed is larger than the maximum width L1 at the lower end between the protrusions 90, 91 to which the light emitting modules 30M and 30C arranged on the lower side are fixed. Similarly, the maximum width at the upper end between the protrusions 91, 92 to which the light emitting module 30K is fixed is larger than the maximum width at the lower end between the protrusions 91, 92 to which the light emitting module 30C arranged on the lower side is fixed.

[0069] More specifically, at the upper end and lower end between the protrusions 90 and 91, the opposing surfaces facing each other in the left-right direction (X1-X2 direction) have curved portions 96a and 97a and recessed portions 96b and 97b. The curved portions 96a and 97a are each formed by curving along the shape of the bracket 33. The recessed portion 96b is formed by the opposing surfaces of the protrusions 90 and 91 above the curved portion 96a being further recessed outward in the left-right direction (X1-X2 direction). The recessed portion 97b is formed by the opposing surfaces of the protrusions 90 and 91 being further recessed outward in the left-right direction (X1-X2 direction) above the curved portion 97a. The width L2 of the recessed portion 96b in the left-right direction (X1-X2 direction) is larger than the width L1 of the recessed portion 97b in the left-right direction (X1-X2 direction). In this embodiment, the adhesive 95 is disposed in the recessed portions 96b and 97b.

[0070] At this time, the outermost diameter D2 of the laser holder 332 (bracket 33) of the light emitting modules 30K, 30Y arranged on the upper side is larger than the outermost diameter D1 of the laser holder 332 (bracket 33) of the light emitting modules 30C, 30M arranged on the lower side. This makes it possible to make the gap between the laser holder 332 (bracket 33) and the protruding parts 90, 91, 92 uniform in the light emitting modules 30Y, 30C, 30M, 30K arranged vertically. Therefore, it is possible to reduce unevenness in the thickness of the adhesive 95 interposed in the gap between the laser holder 332 (bracket 33) and the protruding parts 90, 91, 92. This makes it possible to stably fix each of the light emitting modules 30Y, 30C, 30M, 30K after adjusting the position.

[0071] Furthermore, in this embodiment, the width L1 of the recess 97b in the left-right direction (X1-X2 direction) is larger than the outermost diameter D1 of the region of the laser holder 332 (bracket 33) that comes into contact with the adhesive 95. This makes it difficult for the light-emitting modules 30M and 30C to come into contact with the protrusions 90, 91, and 92 when fine-tuning the orientation. This makes it possible to widen the adjustable movable region of the light-emitting modules 30C and 30M.

[0072] Similarly, the width L2 of the recess 97b in the left-right direction (X1-X2 direction) is larger than the outermost diameter D2 of the laser holder 332 (bracket 33) in the region that contacts the adhesive 95. This makes it possible to widen the adjustable movable region of the light-emitting modules 30K, 30Y.

[0073] The present invention is not limited to the above-mentioned embodiments, and various modifications are possible within the scope of the present invention. For example, if the shape of the bracket 33 of the light emitting modules arranged on the upper and lower sides is the same as that of the present embodiment, the sequence of the colors of the laser beams D1 to D4 emitted from the light emitting modules 30Y, 30C, 30M, and 30K is not particularly limited. For example, the light emitting module on the upper side may emit a laser beam of C (cyan) or M (magenta). [Industrial Applicability]

[0074] The present invention can be used in an optical scanning device that forms a latent image on a scanned surface by exposure scanning. [Explanation of symbols]

[0075] 1a to 1d Photoconductor drum (image carrier) 2a~2d Charger 3a~3d developing device 4a~4d Container 5 Optical Scanning Device 6a~6d Primary transfer roller 7b~7d Cleaning device 8 Intermediate transfer belt 9 Secondary transfer roller 10 Drive roller 11 Driven roller 12a Pick-up roller 12b Registration roller pair 13 Fixing section 16 Paper feed cassette 17, 18, 19, 20 Paper transport path 30Y, 30C, 30M, 30K Light Emitting Module 32 Coupling Lens 33 Bracket 34 Squeezing section 35 Light emitting element 41 First scanning lens 42 Second scanning lens 45 Polygon Mirror 46 Light source section 48 Case 49a, 49b, 49c Reflecting mirror 70a~70d Dustproof glass 90, 91, 92 protrusion 95 Adhesive 96a, 97a Curved section 96b, 97b recess 100 Image forming device 120 Scanning Optical System 331 Lens Holder 331a opening 332 Laser Holder 332a Circular section 333 Element Holder 481 Storage Unit 481a Bottom wall 481b Peripheral wall 482 Lid 482a Top section 482b Peripheral part 483a~483d Output port D1~D4 Laser light J Rotation axis S paper

Claims

1. a light source unit having a plurality of light emitting modules that emit laser light; a polygon mirror that rotates about a rotation axis extending in a vertical direction to reflect the laser light emitted from the light source unit and scans the peripheral surface of an image carrier in a main scanning direction; a first scanning lens that condenses the laser light reflected by the polygon mirror; the second scanning lens which forms an image of the laser light having passed through the first scanning lens on a peripheral surface of the image carrier; a housing section that houses the light source section, the polygon mirror, the first scanning lens, and the second scanning lens; Equipped with The light emitting module includes: A light emitting element that emits the laser light; a coupling lens that converts the laser light emitted from the light-emitting element into a light that is substantially parallel to a main scanning direction and that collects the light in a sub-scanning direction; a cylindrical bracket extending in the direction in which the laser light is emitted and holding the coupling lens therein; having The storage section includes: A bottom wall portion extending in a direction perpendicular to the rotation axis; A plurality of protrusions protruding upward from an upper surface of the bottom wall portion; having The light-emitting modules are arranged vertically between adjacent protrusions, and the bracket is fixed to the protrusions on both sides via an adhesive.

2. The optical scanning device of claim 1, wherein the maximum width between the protrusions to which the upper light-emitting module among the light-emitting modules arranged in a vertical line is fixed is greater than the maximum width between the protrusions to which the lower light-emitting module is fixed.

3. 3. An optical scanning device as described in claim 1 or claim 2, wherein the outermost diameter of the bracket in the area in contact with the adhesive of the upper light-emitting module among the light-emitting modules arranged in a vertical line is larger than the outermost diameter of the bracket in the area in contact with the adhesive of the lower light-emitting module.

4. The optical scanning device described in claim 3, wherein the bracket of the upper one of the light-emitting modules arranged in a vertical line has a ring-shaped portion protruding from an outer circumferential surface, and the ring-shaped portion is arranged in multiple rows in the direction in which the laser light is emitted.

5. 3. The optical scanning device according to claim 1, wherein the adhesive is made of an ultraviolet curable resin.

6. One or more of the image carriers each having a photosensitive layer formed on a surface thereof; a charging device for charging the image carrier to a predetermined surface potential; 3. The optical scanning device according to claim 1, wherein the surface of the image carrier charged by the charging device is exposed to light to form an electrostatic latent image by attenuating the charge; An image forming apparatus comprising:

Images