JP2023066118A - Optical scanner and image forming apparatus including the same - Google Patents

Abstract

To provide an optical scanner that can prevent a local increase in temperature inside a housing while preventing irradiation of a surface to be scanned with flare light, and an image forming apparatus including the same.SOLUTION: An optical scanner comprises a plurality of light sources, a deflector, at least one first scan lens, at least one second scan lens, a light shielding member, and a housing. The first scan lens is arranged in a first direction orthogonal to a main scanning direction. The second scan lens is arranged in a second direction that is a direction opposite to the first direction. The light shielding member has a plurality of light shielding ribs that are arranged between the first scan lens and the second scan lens and arranged side by side on both sides of the deflector along the main scanning direction, and an airway that is formed between the light shielding ribs adjacent in the main scanning direction. The light shielding ribs are formed slender along the direction of an airflow generated by the rotation of the deflector. The light shielding ribs are arranged without gaps in the main scanning direction in plan view from the first direction and the second direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to an optical scanning device and an image forming apparatus having the same.

2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus includes an optical scanning device that scans a surface (scanned surface) of a photosensitive drum with a light beam emitted from a light source to form an electrostatic latent image. Among such optical scanning devices, there is one that has a plurality of light sources and one deflector in one unit, and performs scanning by distributing light beams emitted from each light source in two directions (Patent Document 1). .

The optical scanning device of Patent Document 1 includes a plurality of light sources, a deflector, a pair of scanning lenses (a first scanning lens and a second scanning lens), and a housing that accommodates them. The deflector deflects the light beams emitted from the light sources by a plurality of deflection surfaces formed on the peripheral surface. Each scanning lens directs the light beam, which is deflected by a deflector and scanned in the main scanning direction (vertical direction shown in FIG. 3 of Patent Document 1), onto the effective exposure area of the surface to be scanned (the surface of the photosensitive drum or the like). form an image. The first scanning lens is arranged in a first direction orthogonal to the main scanning direction (one of left and right directions centering on the deflector shown in FIG. 3 of Patent Document 1). The second scanning lens is arranged in a second direction opposite to the first direction (the other of left and right directions around the deflector shown in FIG. 3 of Patent Document 1).

Here, in an optical scanning device having a pair of scanning lenses as described above, flare light generated by reflection of a light beam on the surface of one scanning lens passes through the other scanning lens and is irradiated onto the surface to be scanned. There is a risk that it will be done. When the surface to be scanned is irradiated with flare light, it causes deterioration in image quality, such as streaky stains, color blurring, and ghost images on the image. In order to prevent such deterioration in image quality, the optical scanning device disclosed in Japanese Patent Application Laid-Open No. 2002-200001 has a light shielding member for preventing flare light from entering between the scanning lenses. The light shielding member is a rectangular plate. The light blocking members are arranged on the first direction side and the second direction side of the deflector.

By the way, in the optical scanning device as described above, the temperature inside the housing may rise due to the heat generated by the drive motor and each electronic component. In a general optical scanning device, rotation of the deflector generates an airflow inside the housing, which agitates the air around the heat source. Therefore, the temperature inside the housing is kept uniform. By arranging the cooling mechanism in contact with the wall surface of the housing, the air inside the housing can be cooled through the wall surface of the housing.

JP-A-2002-196269

By the way, the light shielding member of Japanese Patent Laid-Open No. 2002-200003 is arranged only in a part of the housing with respect to the main scanning direction. That is, a relatively large gap is formed between the inner surface of the housing and the light shielding member in the main scanning direction when viewed from the first direction and the second direction. For this reason, flare light may enter each scanning lens through this gap, leading to deterioration in image quality.

Further, in order to suppress the entrance of flare light, the length of the light shielding member in the main scanning direction is made relatively long so as to separate the space on the first direction side and the space on the second direction side in the housing. If a plurality of light shielding members are arranged, the airflow will be blocked by the light shielding member. As a result, the air in the housing becomes less agitated, and the temperature of a part of the housing (for example, the surroundings of the driving section and each electronic component, which are heat sources) may rise sharply. Since the housing is made of resin, there is a risk of thermal deformation due to high temperatures. If the housing is deformed, the positional relationship of the optical system such as the light source and the scanning lens may be out of order, which may cause a shift in the light condensing position on the surface to be scanned, resulting in image deterioration.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical scanning device capable of suppressing a local temperature rise in a housing while suppressing irradiation of flare light onto a surface to be scanned, and an image forming apparatus having the same. .

In order to achieve the above object, a first configuration of the present invention provides a light source comprising a plurality of light sources, a deflector, at least one first scanning lens, at least one second scanning lens, and a housing. A scanning device. The deflector is rotatably supported and deflects light beams emitted from each light source by a plurality of deflection surfaces formed on the outer peripheral surface. The first scanning lens is arranged in a first direction orthogonal to the main scanning direction, and forms an image of the light beam deflected by the deflector and scanned in the main scanning direction on the effective exposure area of the surface to be scanned. A second scanning lens is arranged in a second direction opposite to the first direction. The housing houses the light source, the deflector, the first scan lens and the second scan lens. The optical scanning device includes a plurality of light shielding ribs arranged on both sides of the deflector along the main scanning direction and arranged between the first scanning lens and the second scanning lens, and between the light shielding ribs adjacent to each other in the main scanning direction. and a light blocking member for blocking flare light of the light beam incident on the first scanning lens and flare light of the light beam incident on the second scanning lens. The light shielding rib is elongated along the direction of the air flow generated by the rotation of the deflector. The light shielding ribs are arranged without gaps in the main scanning direction when viewed in plan from the first direction and the second direction.

According to the first configuration of the present invention, the light shielding ribs forming the light shielding member are arranged without gaps in the main scanning direction when viewed in plan from the first direction and the second direction. Therefore, it is possible to prevent the flare light from leaking from the gap between the light shielding member and the housing and being irradiated onto the surface to be scanned. In addition, the airflow generated by the rotation of the deflector circulates through the space on the first direction side and the space on the second direction side inside the housing through the ventilation path. As a result, the air inside the housing is agitated, and the temperature distribution inside the housing can be brought close to a uniform state. Therefore, it is possible to provide an optical scanning device capable of suppressing local temperature rise in the housing while suppressing irradiation of flare light onto the surface to be scanned.

Schematic cross-sectional view showing the internal structure of the image forming apparatus 100 according to the embodiment of the present invention. FIG. 2 is a cross-sectional plan view schematically showing the configuration inside the housing 39 of the optical scanning device 5; FIG. 2 is a side cross-sectional view of the optical scanning device 5 cut along the AA cross-sectional line shown in FIG. 3 is an enlarged plan view of a part of each light shielding rib 48 shown in FIG. 2. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the internal structure of an image forming apparatus 100 according to an embodiment of the invention. Four image forming units Pa, Pb, Pc, and Pd are arranged in order from the upstream side in the transport direction (the right side in FIG. 1) in the main body of the image forming apparatus 100 (here, a color printer). These image forming units Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow and black). and black images are sequentially formed.

Photoreceptor drums 1a, 1b, 1c and 1d carrying visible images (toner images) of respective colors are disposed in these image forming portions Pa to Pd. Further, an intermediate transfer belt 8 that rotates clockwise in FIG. 1 is provided adjacent to each of the image forming portions Pa to Pd. The toner images formed on these photoreceptor drums 1a to 1d are sequentially primary-transferred and superimposed on an intermediate transfer belt 8 that moves in contact with each of the photoreceptor drums 1a to 1d. After that, the toner image primarily transferred onto the intermediate transfer belt 8 is secondarily transferred onto a sheet S (recording medium) as an example of a recording medium by a secondary transfer roller 9 . Further, the sheet S on which the toner image has been secondarily transferred is ejected from the main body of the image forming apparatus 100 after the toner image is fixed by the fixing device 13 . A main motor (not shown) rotates the photosensitive drums 1a to 1d in the counterclockwise direction in FIG. 1, and an image forming process is performed on each of the photosensitive drums 1a to 1d.

The paper S onto which the toner image is to be secondarily transferred is accommodated in a paper cassette 16 arranged at the bottom of the main body of the image forming apparatus 100, and is transferred to the secondary transfer roller 9 via a paper feed roller 12a and a pair of registration rollers 12b. and the driving roller 11 of the intermediate transfer belt 8 . A dielectric resin sheet is used for the intermediate transfer belt 8, and a seamless belt is mainly used. Further, a blade-shaped belt cleaner 19 for removing toner and the like remaining on the surface of the intermediate transfer belt 8 is arranged on the downstream side of the secondary transfer roller 9 .

Next, the image forming units Pa to Pd will be described. Charging devices 2a, 2b, 2c and 2d for charging the photosensitive drums 1a to 1d and image information on the respective photosensitive drums 1a to 1d are provided around and below the rotatably arranged photosensitive drums 1a to 1d. , developing devices 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and developer (toner) remaining on the photosensitive drums 1a to 1d. Cleaning devices 7a, 7b, 7c and 7d are provided for removing.

When image data is input from a host device such as a personal computer, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the charging devices 2a to 2d. Then, the optical scanning device 5 irradiates the photosensitive drums 1a to 1d with light in accordance with the image data to form electrostatic latent images in accordance with the image data. Each of the developing devices 3a to 3d is filled with a predetermined amount of two-component developer containing toner of each color of cyan, magenta, yellow and black. When the ratio of the toner in the two-component developer filled in each of the developing devices 3a to 3d falls below a specified value due to the formation of a toner image, which will be described later, each of the developing devices 3a to 3d is removed from the toner containers 4a to 4d. Toner is supplied to the The toner in the developer is supplied onto the photosensitive drums 1a-1d by the developing devices 3a-3d and adheres electrostatically. As a result, a toner image corresponding to the electrostatic latent image formed by exposure from the optical scanning device 5 is formed.

Then, an electric field is applied between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d by the primary transfer rollers 6a to 6d with a predetermined transfer voltage, and the cyan, magenta, yellow and yellow colors on the photosensitive drums 1a to 1d are transferred. A black toner image is primarily transferred onto the intermediate transfer belt 8 . These four-color images are formed with a predetermined positional relationship for predetermined full-color image formation. After that, in preparation for subsequent formation of new electrostatic latent images, cleaning devices 7a to 7d remove toner and the like remaining on the surfaces of the photosensitive drums 1a to 1d after the primary transfer.

The intermediate transfer belt 8 is stretched between a driven roller 10 on the upstream side and a drive roller 11 on the downstream side. When the paper S starts to rotate in the direction, the paper S is conveyed from the registration roller pair 12b to the nip portion between the drive roller 11 and the secondary transfer roller 9 provided adjacent thereto at a predetermined timing, and is transferred onto the intermediate transfer belt 8. A full-color image is secondarily transferred onto the paper S. The sheet S on which the toner image has been secondarily transferred is conveyed to the fixing device 13 .

The sheet S conveyed to the fixing device 13 is heated and pressed by the fixing belt 21 and the pressure roller 22 to fix the toner image on the surface of the sheet S, forming a predetermined full-color image. The paper S on which the full-color image is formed is divided in the conveying direction by the branching unit 30 branched in a plurality of directions, and is sent to the double-sided conveying path 18 as it is (or after the images are formed on both sides thereof), and is sent to the pair of discharge rollers. 15 to the ejection tray 17 .

Next, the optical scanning device 5 according to the first embodiment of the invention will be described in detail with reference to FIGS. 2 to 4. FIG. FIG. 2 is a cross-sectional plan view schematically showing the configuration inside the housing 39 of the optical scanning device 5. As shown in FIG. FIG. 3 is a side cross-sectional view of the optical scanning device 5 cut along the AA cross-sectional line shown in FIG. FIG. 4 is a plan view enlarging a part of each light shielding rib 48 shown in FIG. Hereinafter, the direction in which the polygon mirror 45 scans the surface to be scanned with the light beam LB (vertical direction in FIG. 2 and horizontal direction in FIG. 3) is referred to as a main scanning direction. Among the directions perpendicular to the main scanning direction (the left and right direction in FIG. 2), the direction toward one side (the left side in FIG. 2) from the polygon mirror 45 is the first direction, and the direction opposite to the first direction (the right side in FIG. 2) is the first direction. ) is called the second direction.

As shown in FIGS. 2 and 3, the optical scanning device 5 includes a housing 39, a first light source unit 26 and a second light source unit 27 (light sources) accommodated in the housing 39, a substrate 28, a polygon mirror 45 ( deflector), a first scanning lens 43 , a second scanning lens 44 , and a light shielding member 47 .

The first light source unit 26 and the second light source unit 27 have laser diodes (not shown), and emit light beams LB from the laser diodes. The light beam LB emitted from the laser diode passes through a collimator lens and a cylindrical lens (both not shown) and forms an image on the deflecting surface 62 of the polygon mirror 45 .

The substrate 28 is arranged on the bottom surface 40 of the housing 39 . Various electronic components including a polygon motor 46 (driving section) and a CPU 29 (control section) are mounted on the substrate 28 . A polygon mirror 45 is connected to a polygon motor 46 and rotatably supported. The polygon mirror 45 is rotated by the rotary driving force of the polygon motor 46 . A wire member 25 is connected to the substrate 28 . Due to the rotation of the polygon mirror 45 , an air flow (hereinafter simply referred to as “air flow”) is generated inside the housing 39 . The direction of the airflow is along the rotation direction of the polygon mirror 45 (here, the clockwise direction in FIG. 2) with the polygon mirror 45 as the center.

The wire member 25 is also connected to the main body of the image forming apparatus 100 (not shown). The wire material 25 is a harness in which a plurality of cables are bundled and a multicore connector is provided at the end. The wire member 25 serves as a transmission path for transmitting and receiving electronic signals between the control unit (illustrated) of the image forming apparatus 100 and the board 28 . The wire member 25 is fixed by a fixing member 23 such as a binding band to a harness bridge 24 (bridge member) provided on the upper portion of the housing 39 . The harness bridge 24 is a plate-like member made of resin. The harness bridge 24 is provided so as to pass over the polygon mirror 45 from the inner side surface 37 on one side of the housing 39 in the main scanning direction to the inner side surface 38 on the other side in the main scanning direction.

The polygon mirror 45 is a regular polygonal prism (here, a regular hexagonal prism) with deflection surfaces 62 formed on each side surface. Each deflection surface 62 is a mirror surface, and can reflect and deflect the light beam LB emitted from the first light source unit 26 and the second light source unit 27 . As the polygon mirror 45 rotates, the light beam LB imaged on the deflection surface 62 is deflected and scanned in the main scanning direction (vertical direction in the drawing). The polygon mirror 45 deflects the light beam LB emitted from the first light source unit 26 in the first direction. Also, the polygon mirror 45 deflects the light beam LB emitted from the second light source unit 27 in the second direction.

The first scanning lens 43 and the second scanning lens 44 face each other with the polygon mirror 45 interposed therebetween. The first scanning lens 43 is positioned on the first direction side of the polygon mirror 45 . The second scanning lens 44 is positioned on the second direction side of the polygon mirror 45 . The first scanning lens 43 and the second scanning lens 44 are lenses having fθ characteristics.

Folding mirrors 50 a and 50 b are arranged at a position on the first direction side of the first scanning lens 43 and a position on the second direction side of the second scanning lens 44 in the housing 39 . The folding mirrors 50a and 50 are optical elements such as mirrors having reflecting surfaces capable of reflecting the light beam LB. Although not shown in the drawing, a plurality of folding mirrors are arranged above the folding mirrors 50a and 50b. The light beam LB passing through the first scanning lens 43 and the second scanning lens 44 has its optical path changed by folding mirrors 50a and 50b (including folding mirrors omitted in the drawing), and is projected onto the photosensitive drums 1a to 1d. An image is formed with a spot diameter of a predetermined size.

The light shielding member 47 divides the interior of the housing 39 into a first space S1 on the first direction side of the polygon mirror 45 and a second space S2 on the second direction side of the polygon mirror 45. As shown in FIG. The light shielding member 47 is composed of a plurality of light shielding ribs 48 .

The light shielding ribs 48 are arranged in the main scanning direction from the inner side surface 37 on one side of the housing 39 in the main scanning direction to the inner side surface 38 on the other side. A plurality of light shielding ribs 48 are arranged on both sides of the polygon mirror 45 in the main scanning direction. As shown in FIGS. 2 and 4, the light blocking ribs 48 are elongated along the airflow direction. The light shielding rib 48 is preferably formed such that its thickness increases from the upstream side to the downstream side in the direction of the airflow. Further, the light shielding rib 48 is preferably a member with relatively high light shielding properties (a member with relatively low light transmittance).

Each light shielding rib 48 has a first surface 35 and a second surface 36 extending from the upstream end to the downstream end in the airflow direction. The first surface 35 is closer to the polygon mirror 45 than the second surface 36 is. In a plan view of the light shielding rib 48 in the vertical direction (the paper surface direction of FIGS. 2 and 4), the first surface 35 and the second surface 36 form an arcuate shape that bulges outward from the housing 39 .

A ventilation path 34 is formed by the first surface 35 and the second surface 36 between the light shielding ribs 48 adjacent to each other in the main scanning direction. More specifically, the air passage 34 is formed between the second surface 36 of the light shielding rib 48 closer to the polygon mirror 45 and the first surface 35 of the light shielding rib 48 farther from the polygon mirror 45 . . The first space S<b>1 and the second space S<b>2 communicate with each other via the ventilation path 34 . The airflow generated by the polygon mirror 45 passes through the ventilation path 34 and circulates between the space on the first direction side and the space on the second direction side inside the housing 39 .

The air passage 34 is elongated along the direction of the airflow. Further, the air passage 34 is preferably formed such that the width of the passage (the width in the direction perpendicular to the airflow direction) narrows from the upstream side to the downstream side in the airflow direction. That is, it is preferable that the second surface 36 and the first surface 35 extend so as to approach each other from the upstream side toward the downstream side in the airflow direction.

As shown in FIG. 3, the light shielding ribs 48 are arranged in the main scanning direction (horizontal direction shown in FIG. 3) without gaps when viewed from the first direction and the second direction. Moreover, each light shielding rib 48 has a gap in the vertical direction (the direction perpendicular to the rotating direction of the polygon mirror 45, the vertical direction shown in FIG. 3) between the bottom surface 40 of the housing 39 or the substrate 28. It is preferably arranged so as not to More specifically, the lower end of the light shielding rib 48 at a position overlapping the substrate 28 in the main scanning direction (above the substrate 28, the position above the substrate 28 shown in FIG. 3) is the surface of the substrate 28 or the substrate 28. It preferably reaches a position where it abuts on the surface of each electronic component (connector, CPU 29, wire member 25, etc.) mounted on the substrate. Moreover, it is preferable that the lower end of the light shielding rib 48 at a position not overlapping the substrate 28 in the main scanning direction reaches a position where it abuts on the bottom surface 40 of the housing 39 . Since the bottom surface 40 of the housing 39 is vertically uneven, the lower ends of the light shielding ribs 48 are located at different positions along the unevenness of the bottom surface 40 .

The light blocking ribs 48 are preferably secured to the harness bridge 24 . In this case, the upper end of the light shielding rib 48 is connected to the lower surface of the harness bridge 24 (the surface facing the bottom surface 40 in the vertical direction). Another light-shielding rib 48 is preferably arranged between the adjacent light-shielding ribs 48 in the main scanning direction and at a downstream position in the airflow direction.

By the way, in the conventional optical scanning device 5, a light shielding plate, which is a rectangular plate-like body, is arranged in the housing 39 in order to suppress the irradiation of the surface to be scanned with flare light. The light shielding plate is elongated along the main scanning direction. This light shielding plate is arranged only partly inside the housing 39 with respect to the main scanning direction. That is, a relatively large gap is formed between the inner side surfaces 37 and 38 of the housing 39 and the light shielding plate with respect to the main scanning direction when viewed from the first direction and the second direction. Therefore, flare light may enter the first scanning lens 43 and the second scanning lens 44 through this gap, leading to deterioration in image quality.

Further, in the above-described conventional optical scanning device 5, in order to suppress the entrance of flare light, a light shielding plate relatively long in the main scanning direction is provided so as to divide the space inside the housing 39 into the first direction and the second direction. If they are arranged or if a plurality of light shielding plates are arranged side by side without gaps, the airflow will be blocked by the light shielding plates. As a result, the air in the housing 39 becomes less agitated, and the temperature of a part of the housing 39 (for example, around the polygon motor 46 and each electronic component (CPU 29, etc.) that is a heat source) may rise sharply. Since the housing 39 is made of resin, it may be thermally deformed when the internal temperature rises. When the housing 39 is deformed, the positional relationship of the optical system such as the first light source unit 26 and the second light source unit 27, the first scanning lens 43 and the second scanning lens 44 is out of order, and light is condensed on the surface to be scanned. There is a possibility that the position may be misaligned, resulting in image deterioration.

On the other hand, in the optical scanning device 5 of the present embodiment, as described above, the light shielding ribs 48 are arranged without gaps in the main scanning direction when viewed from the first direction and the second direction. Therefore, the flare light of the light beam LB reflected by the lens surface of the first scanning lens 43 and the deflection surface 62 is blocked in the second direction, and it is possible to suppress the flare light from entering the second space S2. can. Similarly, the flare light of the light beam LB reflected by the lens surface of the second scanning lens 44 and the deflection surface 62 is blocked in the first direction, and it is possible to suppress the flare light from entering the first space S1. can. Therefore, it is possible to prevent the flare light from passing through the first scanning lens 43 and the second scanning lens 44 and irradiating the photosensitive drums 1a to 1d, thereby suppressing the image defect caused by the flare light.

Further, as described above, the air passages 34 are formed between the light shielding ribs 48 . The first space S<b>1 and the second space S<b>2 of the housing 39 communicate with each other via the ventilation path 34 . Therefore, the airflow generated by the rotation of the polygon mirror 45 circulates inside the housing 39 through the air passage 34 . As a result, the air inside the housing 39 is agitated. Therefore, it is possible to prevent the heated air from remaining in a part of the housing 39 (the electronic components on the substrate 28 and the area around the polygon motor 46, which are heat sources), thereby suppressing the local temperature rise of the housing 39. can do.

In addition, the light shielding rib 48 and the air passage 34 are elongated along the airflow direction. This makes it easier for the air to pass through the ventilation path 34, so that the air in the housing 39 can be stirred more efficiently.

Further, as described above, it is possible to employ a configuration in which the thickness of the light shielding rib 48 increases from the upstream side toward the downstream side in the airflow direction. In this way, the entrance portion of the ventilation path 34 located at the upstream end of the light shielding rib 48 in the airflow direction is located further than the exit portion of the ventilation path 34 located at the downstream end of the light shielding rib 48 in the airflow direction. becomes wide. Therefore, the air can easily enter the ventilation path 34, and the air inside the housing 39 can be stirred more efficiently. In addition, by forming the second surface 36 and the first surface 35 so as to approach each other from the upstream side to the downstream side with respect to the airflow direction, the inlet portion of the air passage 34 can be widened.

Moreover, as described above, each light shielding rib 48 is preferably arranged so as not to form a gap between it and the bottom surface 40 of the housing 39 or the substrate 28 in the vertical direction. By doing so, the gap between the light shielding rib 48 and the housing 39 and the substrate 28 becomes smaller, and the flare light can be shielded more effectively.

Also, as described above, the light shielding ribs 48 are preferably fixed to the harness bridge 24 . By doing so, the vertical gap between the light shielding rib 48 and the harness bridge 24 is eliminated. Also, since the harness bridge 24 is provided in the upper portion of the housing 39 , the light shielding rib 48 extends to a relatively upper position in the space inside the housing 39 . As a result, flare light can be blocked more effectively. Further, by attaching the harness bridge 24 to which the light shielding ribs 48 are fixed in advance to the housing 39, the light shielding ribs 48 can be arranged inside the housing 39, so that the assembling efficiency of the optical scanning device 5 can be improved. can be done.

In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. For example, two or more first scanning lenses 43 and two or more second scanning lenses 44 may be arranged. In this case, for example, a configuration can be adopted in which a pair of first scanning lenses 43 are arranged on the first direction side of the polygon mirror 45 and a pair of second scanning lenses 44 are arranged on the second direction side. In this case, the light beams LB that irradiate the photosensitive drums 1a to 1d may pass through separate scanning lenses (first scanning lens 43 or second scanning lens 44).

Further, the optical scanning device 5 of the present invention is applicable not only to the color printer shown in FIG. 1, but also to other image forming apparatuses using an optical scanning device, such as a digital multi-function machine and a facsimile machine.

INDUSTRIAL APPLICABILITY The present invention can be used in an optical scanning device having a polygon mirror that deflects a light beam toward multiple scanning lenses arranged in different directions. By using the present invention, it is possible to provide an optical scanning device capable of suppressing a local temperature rise in the housing while suppressing flare light from entering each scanning lens. Further, by using this optical scanning device, it is possible to provide an image forming apparatus capable of suppressing image defects caused by flare light.

5 optical scanner 24 harness bridge (bridge member)
25 wire material 26 first light source unit 27 second light source unit 28 substrate 29 CPU (control unit)
34 air passage 35 first surface 36 second surface 37, 38 inner surface 39 housing 40 bottom surface 43 first scanning lens 44 second scanning lens 45 polygon mirror (deflector)
46 polygon motor (drive part)
47 light shielding member 48 light shielding rib 62 deflection surface 100 image forming apparatus LB light beam

Claims (8)

a plurality of light sources;
a deflector that is rotatably supported and deflects the light beams emitted from the light sources by a plurality of deflection surfaces formed on the outer peripheral surface;
At least one first scanning arranged in a first direction orthogonal to the main scanning direction for forming an image of the light beam deflected by the deflector and scanned in the main scanning direction on an effective exposure area of the surface to be scanned. a lens;
at least one second scanning lens arranged in a second direction opposite to the first direction;
a housing that houses the light source, the deflector, the first scanning lens, and the second scanning lens;
In an optical scanning device comprising:
a plurality of light shielding ribs arranged on both sides of the deflector along the main scanning direction and arranged between the first scanning lens and the second scanning lens; and a light shielding member for shielding flare light of the light beam incident on the first scanning lens and flare light of the light beam incident on the second scanning lens. ,
The light shielding rib is elongated along the direction of the air flow generated by the rotation of the deflector,
The optical scanning device, wherein the light shielding ribs are arranged without gaps in the main scanning direction when viewed in plan from the first direction and the second direction. Among the light shielding ribs, the pair of light shielding ribs positioned on the outermost side in the main scanning direction are positioned between the inner side surface of the housing when viewed from the first direction and the second direction. 2. The optical scanning device according to claim 1, wherein the optical scanning device is arranged such that there is no gap between the two. 3. The optical scanning device according to claim 1, wherein the thickness of the light shielding rib increases from the upstream side to the downstream side in the direction of the air flow. A first surface of the light shielding rib on a side closer to the deflector and a second surface on a side farther from the deflector are arcuate along the direction of the air flow,
The air passage is formed between the second surface of the light shielding rib closer to the deflector and the first surface of the light shielding rib farther from the deflector, and extends in the direction of the air flow. 4. The optical scanning device according to claim 1, wherein said second surface and said first surface extend toward each other from upstream to downstream. 2. Both ends of the light shielding rib are located outside the deflection surface with respect to a height direction orthogonal to the first direction, the second direction and the scanning direction. 5. The optical scanning device according to any one of 4. a driving unit connected to the deflector and applying a rotational driving force to the deflector;
a control unit connected to the light source and the driving unit and configured to control the rotational driving force;
a substrate on which the driving unit and the control unit are mounted, arranged on the bottom surface of the housing at a position overlapping the light shielding member in the first direction and the second direction;
a bridge member provided so as to pass above the deflector from one to the other inner surface of the housing facing the main scanning direction with the deflector interposed therebetween;
a wire material fixed to the bridge member, which is a transmission path for an electrical signal transmitted and received by the substrate;
with
6. The optical scanning device according to claim 1, wherein the light shielding rib extends from the lower surface of the bridge member to a position below the deflection surface. The lower end portion of the light shielding rib located above the substrate of each light shielding rib contacts the surface of the substrate or the electronic component mounted on the substrate, and the other light shielding rib of each light shielding rib contacts the surface of the electronic component mounted on the substrate. 7. The optical scanning device according to claim 6, wherein the lower end of the light shielding rib is in contact with the bottom surface of the housing. An image forming apparatus comprising the optical scanning device according to claim 1 .

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