JP5370271B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device.

  In general, an image forming apparatus such as a laser printer is provided with an optical scanning device that exposes the surface of a photoreceptor. As such an optical scanning device, for example, as shown in Patent Document 1, a light source (semiconductor laser), a deflector (rotating polygonal mirror) that deflects and scans laser light from the light source, and an image writing timing are determined. For this purpose, a beam detector (photoelectric element) that receives laser light and a mirror that reflects laser light reflected by a deflector toward the beam detector are known.

Japanese Patent Laying-Open No. 2008-185589 (FIG. 2)

  By the way, in the optical scanning device, an aperture (aperture) is provided between the light source and the deflector and between the mirror and the beam detector in order to define the width of the laser light applied to the deflector and the beam detector. Sometimes. Such an opening is provided by forming directly on a wall of a housing that supports a light source, a beam detector, or the like, or by attaching a plate having an aperture formed on the housing. However, the configuration of the conventional optical scanning device has a problem in that the configuration and molding of the housing are complicated by providing a plurality of openings.

  SUMMARY An advantage of some aspects of the invention is that it simplifies the configuration of a housing in an optical scanning device having a plurality of openings for defining the width of a light beam.

  To achieve the above object, an optical scanning device of the present invention is deflected by a light source, a deflector that deflects and scans a light beam from the light source, a beam detector that detects a light beam, and the deflector. An optical scanning device comprising: a mirror that reflects a light beam toward the beam detector; and a housing that houses the light source, the deflector, the beam detector, and the mirror. A series of internal walls standing in the housing, wherein the light source and the beam detector are arranged on the opposite side of the deflector and the mirror across the internal wall; A first opening through which a light beam from the light source toward the deflector passes and a second opening through which a light beam from the mirror toward the beam detector passes. A peripheral wall of the first opening is formed by: Parallel to one direction, Is inclined so as to spread toward the one direction, and the peripheral wall of the second opening is inclined so as to extend parallel to the one direction or toward the one direction. To do.

  According to the optical scanning device configured as described above, the first opening and the second opening are formed in the series of inner walls in the casing, so that it is compared with a configuration in which a plate having an opening formed in the casing is attached. Thus, the configuration and assembly of the housing can be simplified. Further, since the peripheral wall of the first opening and the peripheral wall of the second opening are inclined so as to extend parallel to one direction or toward one direction, when the housing is molded by injecting resin into the mold Since the two openings can be formed at the same time by removing the mold (nesting) in one direction, it is possible to simplify the forming of the housing.

  According to the present invention, the first opening and the second opening are formed in the series of inner walls in the housing, and the peripheral wall of each opening is inclined so as to extend in parallel to one direction or in one direction. Therefore, the configuration and molding of the housing can be simplified.

1 is a diagram illustrating a schematic configuration of a laser printer including an optical scanning device according to an embodiment. It is a top view of an optical scanning device. It is a perspective view of a base frame. It is XX sectional drawing of FIG. It is sectional drawing of an internal wall. It is a figure which shows the effect | action of a 2nd opening. It is a figure which shows the structure of the internal wall which concerns on a modification. It is a figure which shows the structure of the internal wall which concerns on another modification.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the schematic configuration of the image forming apparatus including the optical scanning device according to the embodiment of the present invention will be described first, and then the detailed configuration of the optical scanning device will be described.

<Schematic configuration of laser printer>
As shown in FIG. 1, a laser printer 1 (image forming apparatus) includes a paper feed unit 3 for feeding paper S and an image forming unit 4 for forming an image on the paper S in a main body housing 2. It is mainly equipped with.

  Here, in the description of the schematic configuration of the laser printer 1, the direction will be described with reference to the user who uses the laser printer 1. That is, the right side in FIG. 1 is “front (front)”, the left side is “rear (back)”, the front side is “left”, and the back side is “right”. Also, the vertical direction in FIG.

  The paper feed unit 3 is provided at a lower portion in the main body housing 2 and mainly includes a paper feed tray 31, a paper pressing plate 32, and a paper feed mechanism 33. The paper S stored in the paper feed tray 31 is moved upward by the paper pressing plate 32 and supplied to the image forming unit 4 by the paper feed mechanism 33.

  The image forming unit 4 mainly includes an optical scanning device 5, a process cartridge 6, and a fixing device 7.

  The optical scanning device 5 is arranged at the upper part in the main body housing 2 so as to emit laser light (refer to a chain line) based on image data and expose the surface of the photosensitive drum 61 to form an electrostatic latent image. It is configured. The detailed configuration of the optical scanning device 5 will be described later.

  The process cartridge 6 is disposed below the optical scanning device 5 and is detachably attached to the main body housing 2 through an opening formed when a front cover (reference number omitted) provided on the main body housing 2 is opened. It has a configuration. The process cartridge 6 includes a photosensitive drum 61, a charger 62, a transfer roller 63, a developing roller 64, a layer thickness regulating blade 65, a supply roller 66, and a toner storage unit that stores toner (developer). 67 mainly.

  In the process cartridge 6, the surface of the photosensitive drum 61 is uniformly charged by the charger 62 and then exposed to the laser beam from the optical scanning device 5, so that the photosensitive drum 61 is based on the image data. An electrostatic latent image is formed. Further, the toner in the toner container 67 is supplied to the developing roller 64 via the supply roller 66 and enters between the developing roller 64 and the layer thickness regulating blade 65 to form a thin layer having a constant thickness. Supported on.

  The toner carried on the developing roller 64 is supplied from the developing roller 64 to the electrostatic latent image formed on the photosensitive drum 61. As a result, the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 61. Thereafter, the sheet S is conveyed between the photosensitive drum 61 and the transfer roller 63, whereby the toner image on the photosensitive drum 61 is transferred onto the sheet S.

  The fixing device 7 is provided behind the process cartridge 6, and mainly includes a heating roller 71 and a pressure roller 72 that is disposed to face the heating roller 71 and presses the heating roller 71. In the fixing device 7, the toner image transferred onto the paper S is thermally fixed while the paper S passes between the heating roller 71 and the pressure roller 72. The sheet S on which the toner image has been heat-fixed is conveyed on the conveyance path 23 by the conveyance roller 73 and is discharged from the conveyance path 23 onto the paper discharge tray 22 by the discharge roller 24.

<Detailed configuration of optical scanning device>
As shown in FIG. 2, the optical scanning device 5 includes a light source device 51, a cylindrical lens 52 as an example of a first lens, and a polygon mirror 53 as an example of a deflector in a scanner housing 50 (housing). And a scanning lens 54, reflecting mirrors 55 and 56, a condensing lens 57 as an example of a second lens, a beam detector 58, and a control board 59 as an example of a substrate.

  In the present embodiment, the light source device 51 (semiconductor laser 51 </ b> A) and the beam detector 58 are sandwiched between a series of internal walls 100 (hatched portions) provided in the scanner housing 50, and the polygon mirror 53 and the reflection. The mirror 56 is disposed on the opposite side. The detailed configuration of the scanner housing 50 will be described later.

  The light source device 51 includes a semiconductor laser 51A as an example of a light source that emits laser light (light beam), a coupling lens (not shown) that condenses the laser light emitted from the semiconductor laser 51A and converts it into a parallel light beam, and the like. It is configured with.

  The cylindrical lens 52 is a lens through which laser light emitted from the light source device 51 and directed to the polygon mirror 53 passes. The cylindrical lens 52 refracts the laser light emitted from the light source device 51, converges it in the sub-scanning direction (direction orthogonal to the main scanning direction), and condenses it on the polygon mirror 53 (reflection surface).

  The polygon mirror 53 has six side surfaces of the hexagonal prism as reflection surfaces, reflects the laser light from the light source device 51 while rotating at high speed, deflects in the main scanning direction (vertical direction in FIG. 2), and has an equal angular velocity. Scan.

  The scanning lens 54 is a lens through which the laser beam deflected and scanned by the polygon mirror 53 passes. The scanning lens 54 converts the laser beam scanned at a constant angular velocity by the polygon mirror 53 so as to scan at a uniform velocity, refracts the laser beam reflected by the polygon mirror 53 and converges it in the sub-scanning direction, By condensing on the surface of the photosensitive drum 61, the surface tilt of the polygon mirror 53 is corrected.

  The reflecting mirror 55 reflects the laser beam that has passed through the scanning lens 54 toward the photosensitive drum 61 (see also FIG. 1).

  The reflecting mirror 56 (mirror) is disposed between the polygon mirror 53 and the scanning lens 54 in the optical axis direction (left and right direction in FIG. 2) of the scanning lens 54, and the laser beam reflected (deflected) by the polygon mirror 53. Is reflected toward the beam detector 58.

  The condensing lens 57 is a lens through which laser light traveling from the reflecting mirror 56 toward the beam detector 58 passes. The condensing lens 57 refracts the laser light reflected by the reflecting mirror 56 and converges it in the main scanning direction and the sub-scanning direction, and condenses it on the detection surface of the beam detector 58.

  The beam detector 58 is a sensor that detects laser light. In the optical scanning device 5, the light source device 51 (semiconductor laser 51A) is appropriately blinked based on the image data after a predetermined time has elapsed since the laser beam was detected by the beam detector 58. As a result, the image writing position on the surface (scanned surface) of the photosensitive drum 61 can be made uniform. Since the configuration and control for aligning the writing position on the surface to be scanned are well known, detailed description is omitted in this specification.

  The control board 59 controls blinking of the semiconductor laser 51A, driving of the polygon mirror 53, and the like based on an input from a control device (not shown) provided in the laser printer 1. A semiconductor laser 51A and a beam detector 58 are fixed to the control board 59 by soldering or the like. In other words, the semiconductor laser 51A and the beam detector 58 are provided on the same control board 59.

  In the optical scanning device 5, the laser light based on the image data emitted from the light source device 51 is reflected or passed through the cylindrical lens 52, the polygon mirror 53, the scanning lens 54, and the reflecting mirror 55 in this order, so 1)) at high speed. As a result, the surface of the photosensitive drum 61 is exposed, and an electrostatic latent image based on the image data is formed on the photosensitive drum 61.

[Detailed configuration of scanner housing]
The scanner housing 50 is a housing that houses the light source device 51, the polygon mirror 53, the reflecting mirror 56, the beam detector 58, and the like. The scanner housing 50 mainly includes a box-shaped base frame 50A whose upper side in FIG. 1 is opened and a lid frame 50B attached so as to cover the base frame 50A.

  The base frame 50A and the lid frame 50B (scanner casing 50) are molded by injecting molten resin into a mold, such as injection molding, and curing the resin and then removing it from the mold. Since such a molding method (manufacturing method) is publicly known, detailed description is omitted in this specification.

  As shown in FIG. 3, the base frame 50 </ b> A extends from the bottom wall 50 </ b> C so as to stand up from the bottom wall 50 </ b> C and connect the bottom wall 50 </ b> C and the upper wall 50 </ b> D (see FIG. 4) of the lid frame 50 </ b> B. It mainly has the side wall part 50E and the inner wall 100. Further, as shown in FIG. 4, the lid frame 50B mainly has an upper wall portion 50D that faces the bottom wall portion 50C. The bottom wall portion 50C, the upper wall portion 50D, and the side wall portion 50E constitute an outer wall of the optical scanning device 5.

  Note that the “upper” of the upper wall portion 50D and the “bottom” of the bottom wall portion 50C are referred to as “upper” or “bottom” for convenience of explanation, and the upper and lower sides of the scanner housing 50 (optical scanning device 5). It does not necessarily match the direction. That is, when the optical scanning device 5 is attached to the laser printer 1 (main body housing 2), the bottom wall portion 50C may be positioned above the upper wall portion 50D.

  As shown in FIG. 3, the inner wall 100 is a series of walls erected in the scanner housing 50 (in a space surrounded by the bottom wall portion 50C, the upper wall portion 50D, and the side wall portion 50E). The wall portion 101, the second wall portion 102, the first support portion 103, and the second support portion 104 are provided.

  The inner wall 100 is provided so as to extend upward in FIG. 4 from the inner surface of the bottom wall portion 50C, and its end surface is in contact with the inner surface of the upper wall portion 50D. That is, the inner wall 100 reaches the upper wall portion 50D. As a result, the lid frame 50B can be supported from below, so that the rigidity of the scanner housing 50 can be improved, and compared with a configuration in which a reinforcing wall is provided separately from the internal wall 100, the scanner housing 50 can be improved. The configuration of the body 50 can be simplified.

  As shown in FIG. 2, the inner wall 100 has a space in the scanner housing 50, a space S <b> 1 in which the light source device 51 (semiconductor laser 51 </ b> A), the beam detector 58, and the like are arranged, a polygon mirror 53, and a reflection. It is provided so as to partition into a space S2 in which a mirror 56 and the like are arranged. As a result, the laser light emission region and the laser light scanning region are separated, so that unnecessary light can be prevented from entering the scanning region (space S2) from the light emission region (space S1). In particular, in the present embodiment, since the inner wall 100 reaches the upper wall portion 50D, it is possible to more reliably suppress unnecessary light from entering the scanning region.

  If unnecessary light enters the scanning region, the light is reflected by the polygon mirror 53, passes through the scanning lens 54, is reflected by the reflecting mirror 55, and reaches the surface of the photosensitive drum 61. is there. Then, when unnecessary light reaches the photosensitive drum 61, it becomes a so-called ghost and there is a possibility that the image quality is lowered. However, in the configuration of the present embodiment, since the light emitting area (space S1) and the scanning area (space S2) are partitioned by the inner wall 100, unnecessary light hardly reaches the photosensitive drum 61, and image quality is improved. The decrease can be suppressed.

  As shown in FIG. 5, the first wall portion 101 is a portion located between the light source device 51 and the cylindrical lens 52 facing each other in the series of inner walls 100. The first wall 101 is formed with a first opening 110 through which laser light directed from the light source device 51 (semiconductor laser 51A) toward the polygon mirror 53 (see FIG. 2) passes.

  The first opening 110 has a substantially rectangular shape when viewed from a direction orthogonal to the first wall portion 101 (see FIG. 4), and passes through the laser light (laser light converted into a light beam by a coupling lens). Define the width. The peripheral wall 111 of the first opening 110 is inclined so as to spread in one direction indicated by a one-dot chain line arrow in FIG.

  The second wall portion 102 is a portion located between the condensing lens 57 and the beam detector 58 facing each other in the series of inner walls 100. The second wall portion 102 is formed with a second opening 120 through which laser light traveling from the reflecting mirror 56 (see FIG. 2) toward the beam detector 58 passes.

  The second opening 120 has an elongated slit shape in the main scanning direction (left-right direction in FIG. 4) of the laser light reflected by the reflecting mirror 56 when viewed from the direction orthogonal to the second wall 102. As shown in FIG. 4, the width of the laser beam passing therethrough is mainly defined in the sub-scanning direction.

  Here, in the optical scanning device 5 of this embodiment, the optical path length of the laser light from the semiconductor laser 51A to the beam detector 58 is made shorter than the optical path length of the laser light from the semiconductor laser 51A to the photosensitive drum 61. So, we are trying to reduce the size. Therefore, the laser light is rapidly converged in the main scanning direction and the sub-scanning direction by the condensing lens 57, thereby condensing the laser light on the detection surface of the beam detector 58.

  In such a configuration, when the focal position of the condensing lens 57 is shifted in the optical axis direction due to a manufacturing error of the scanner housing 50 or the like, a portion where the light intensity is strong on the detection surface of the beam detector 58 (hereinafter referred to as a peak). .) May appear in the sub-scanning direction. At this time, if the peak detected due to the surface tilt of the polygon mirror 53 changes, the image writing position may be shifted.

  Therefore, in this embodiment, the second opening 120 is formed in a slit shape elongated in the main scanning direction, and the width of the laser light mainly in the sub scanning direction is defined, so that a peak is detected on the detection surface of the beam detector 58. Multiple occurrences in the sub-scanning direction are suppressed. This makes it possible to stabilize the image writing position.

  As shown in FIG. 5, the peripheral wall 121 of the second opening 120 is inclined so as to expand toward one direction (refer to the dashed line arrow) that is the same as the direction in which the peripheral wall 111 of the first opening 110 expands. Yes.

  As described above, the first wall portion 101 (the portion of the inner wall 100 where the first opening 110 is formed) and the second wall portion 102 (the portion of the inner wall 100 where the second opening 120 is formed) are mutually connected. Parallel.

  The first support portion 103 is a portion that supports the cylindrical lens 52, and is provided on the scanning region side (space S2 side (see FIG. 2)) of the first wall portion 101. Further, the second support portion 104 is a portion that supports the condenser lens 57 and is provided on the scanning region side of the second wall portion 102. By providing the first support portion 103 and the second support portion 104 on the inner wall 100 as described above, the configuration of the scanner housing 50 is simplified as compared with a configuration in which a lens support portion is provided separately from the inner wall 100. can do.

According to the above, the following effects can be obtained in the present embodiment.
Since the first opening 110 and the second opening 120 are formed in the series of inner walls 100 in the scanner housing 50, the scanner is compared with a configuration in which a plate having an opening formed in the scanner housing 50 is attached. The configuration and assembly of the housing 50 can be simplified.

  Further, since the peripheral wall 111 of the first opening 110 and the peripheral wall 121 of the second opening 120 are inclined so as to spread in the same direction (one direction), the scanner housing 50 (base frame 50A) is used as a mold. In the process of injecting and molding the resin, the first opening 110 and the second opening 120 can be simultaneously formed by simply pulling out one mold (nesting). Thereby, the shaping | molding of the scanner housing | casing 50 can be simplified. In the present embodiment, the removal direction of the mold (nesting) corresponds to “one direction”.

  In addition, since the first opening 110 and the second opening 120 (a plurality of openings) can be formed at the same time, the positional accuracy of the openings can be compared with the configuration in which the openings are provided individually. Further, it is possible to improve the mounting position accuracy with respect to the plurality of openings of the control board 59 on which the semiconductor laser 51A and the beam detector 58 are provided.

  Further, since the first wall portion 101 and the second wall portion 102 are parallel, the mold (nesting) can be released from the inner wall 100 relatively easily, and the scanner housing 50 is easily formed. can do.

  Further, since the semiconductor laser 51A and the beam detector 58 are provided on the same control substrate 59, the semiconductor laser 51A and the beam detector 58 are compared with the configuration in which the semiconductor laser 51A and the beam detector 58 are provided on different substrates, respectively. The position accuracy of the beam detector 58 can be improved. Further, the positional accuracy of the first opening 110 and the semiconductor laser 51A and the positional accuracy of the second opening 120 and the beam detector 58 can be improved.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

  In the said embodiment, although the surrounding wall 111 of the 1st opening 110 and the surrounding wall 121 of the 2nd opening 120 illustrated incline so that it might spread toward one direction, it is not limited to this. . For example, as shown in FIG. 7, the peripheral wall 112 of the first opening 110 and the peripheral wall 122 of the second opening 120 may be configured to be parallel to one direction indicated by a one-dot chain line arrow. Even in such a configuration, the first opening 110 and the second opening 120 can be simultaneously formed by simply pulling out one mold (nesting) in the process of forming the scanner housing 50. The molding of the scanner housing 50 can be simplified.

  In addition, although not particularly described in the above-described embodiment, the peripheral wall 111 of the first opening 110 and the peripheral wall 121 of the second opening 120 may or may not extend all around in one direction. Also good. Similarly, the peripheral wall 112 of the first opening 110 and the peripheral wall 122 (see FIG. 7) of the second opening 120 may or may not be parallel to the entire direction.

  That is, for example, a pair of walls may be inclined in one direction among two pairs of opposing walls of a substantially rectangular opening, and the other pair of walls may be parallel to the one direction. Further, among the four walls of the substantially rectangular opening, three walls may be inclined toward one direction, and the remaining one wall may be parallel to the one direction. Further, among the four walls of the substantially rectangular opening, two adjacent walls may be inclined in one direction, and another two adjacent walls may be parallel to the one direction.

  In the embodiment, the configuration in which the second opening 120 has a slit shape that is long in the main scanning direction is exemplified, but the present invention is not limited to this. For example, similar to the first opening 110 in the embodiment, the second opening 120 has a substantially rectangular shape. It is good also as composition which makes. That is, in the present invention, the shape of the second opening and the first opening is not particularly limited as long as it defines the width of the light beam passing therethrough (functions as a so-called aperture).

  In the embodiment, the configuration in which the first opening 110 is formed in the first wall portion 101 and the second opening 120 is formed in the second wall portion 102 is exemplified, but the present invention is not limited to this. And the second opening may be formed on the same wall.

  In the said embodiment, the 1st wall part 101 (part in which the 1st opening was formed among internal walls) and the 2nd wall part 102 (part in which the 2nd opening was formed among internal walls) are parallel. Although illustrated, it is not limited to this. For example, it is good also as a structure from which the part (surface) in which the 1st opening was formed in the inner wall and the part (surface) in which the 2nd opening were formed faced a different direction. Specifically, as shown in FIG. 8, a first wall 201 in which a first opening 110 is formed and a second wall 202 in which a second opening 120 is formed extend in different directions. It is good also as a structure which is, ie, a structure which is not mutually parallel. With such a configuration, the rigidity of the scanner housing 50 can be improved.

  In the above embodiment, the configuration in which the semiconductor laser 51A (light source) and the beam detector 58 are provided on the same control board 59 (substrate) is illustrated, but the present invention is not limited to this, and the light source and the beam detector are different. It is good also as a structure provided on a board | substrate.

  In the embodiment, the configuration in which the inner wall 100 supports the cylindrical lens 52 (first lens) and the condenser lens 57 (second lens) (configuration including the first support portion 103 and the second support portion 104) is exemplified. However, the present invention is not limited to this. That is, it is good also as a structure which provides the support part of a lens separately from an internal wall.

  In the above-described embodiment, the configuration in which the inner wall 100 is provided on the bottom wall portion 50C and reaches the upper wall portion 50D (the lid frame 50B) is exemplified. However, the present invention is not limited to this, and for example, the inner wall and the upper wall portion It is good also as a structure with a clearance gap between.

  In the above embodiment, the configuration in which the space in the scanner housing 50 is partitioned by the inner wall 100 into the light emitting region (space S1) and the scanning region (space S2) is exemplified, but the present invention is not limited to this. . That is, the inner wall may be configured not to partition the light emitting region and the scanning region. Note that, as in the above-described embodiment, the inner wall 100 partitions the light emitting region and the scanning region, so that the deterioration of the image quality can be suppressed and the rigidity of the scanner housing 50 can be improved.

  In the embodiment, the configuration in which the laser light (light beam) converted into the parallel light beam is emitted from the light source device 51 is exemplified. However, the configuration is not limited thereto, and for example, the configuration in which convergent light or divergent light beam is emitted. It is good.

  In the embodiment, the polygon mirror 53 that deflects and scans the laser beam (light beam) by rotating the reflection surface is exemplified as the deflector. However, the present invention is not limited to this, and for example, the reflection surface is swung. A vibrating mirror that deflects and scans the light beam may be employed.

  In the above embodiment, the cylindrical lens 52 is exemplified as the first lens and the condensing lens 57 is exemplified as the second lens. However, the present invention is not limited to this, and other types of lenses may be appropriately employed. The present invention may be configured without the first lens and / or the second lens.

  In the above-described embodiment, the laser printer 1 is exemplified as the image forming apparatus. However, the image forming apparatus is not limited thereto, and may be a copying machine, a multifunction machine, or the like. In the above embodiment, the optical scanning device of the present invention is applied to the image forming apparatus (laser printer 1). However, the present invention is not limited to this. For example, the optical scanning device may be applied to a measuring device or an inspection device. Good.

DESCRIPTION OF SYMBOLS 5 Optical scanning device 50 Scanner housing | casing 50C Bottom wall part 50D Top wall part 50E Side wall part 51 Light source device 51A Semiconductor laser 52 Cylindrical lens 53 Polygon mirror 56 Reflecting mirror 57 Condensing lens 58 Beam detector 59 Control board 100 Inner wall 101 1st 1st wall part 102 2nd wall part 103 1st support part 104 2nd support part 110 1st opening 111 Peripheral wall 120 2nd opening 121 Peripheral wall S1 space S2 space

Claims (8)

A light source, a deflector that deflects and scans a light beam from the light source, a beam detector that detects the light beam, a mirror that reflects the light beam deflected by the deflector toward the beam detector, and An optical scanning device comprising a light source, the deflector, the beam detector, and a housing that houses the mirror,
The casing has a series of internal walls standing in the casing,
The light source and the beam detector are arranged on the opposite side of the deflector and the mirror across the inner wall,
A first opening through which a light beam from the light source toward the deflector passes and a second opening through which the light beam from the mirror toward the beam detector passes are formed in the inner wall,
The peripheral wall of the first opening is inclined so as to be parallel to one direction or spread toward the one direction,
The peripheral wall of the second opening is inclined so as to be parallel to the one direction or to expand toward the one direction.   2. The optical scanning device according to claim 1, wherein a portion in which the first opening is formed and a portion in which the second opening is formed in the inner wall are parallel to each other.   2. The optical scanning device according to claim 1, wherein a portion of the inner wall where the first opening is formed and a portion where the second opening is formed face different directions.   4. The optical scanning device according to claim 1, wherein the light source and the beam detector are provided on the same substrate. 5.   The said 2nd opening makes | forms the slit shape long in the main scanning direction, and prescribes | regulates the width | variety of the subscanning direction of the light beam to pass through. Optical scanning device. A first lens through which a light beam from the light source toward the deflector passes, and a second lens through which a light beam from the mirror toward the beam detector passes,
The optical scanning device according to claim 1, wherein the inner wall supports the first lens and the second lens. The housing includes a bottom wall portion constituting an outer wall, an upper wall portion facing the bottom wall portion, and a side wall portion extending so as to connect the bottom wall portion and the upper wall portion,
The optical scanning device according to claim 1, wherein the inner wall is provided on the bottom wall portion and reaches the upper wall portion.   The space in the casing is partitioned by the internal wall from a space in which the light source and the beam detector are arranged and a space in which the deflector and the mirror are arranged. The optical scanning device according to claim 7.

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