Scanning optical apparatus and image forming apparatus

Abstract

To maintain dustproof performance, improve assembly working efficiency when mounting a transmission member to a casing, and suppress deformation of the transmission member and the casing because of a difference in a coefficient of linear expansion between the transmission member and the casing.SOLUTION: In a scanning optical device 101 comprises a deflection device 5, an fθ lens 9, an opening 12, a transmission member 11, an optical box 10, and a lid 101a while laser luminous fluxes are emitted outside from the transmission member 11. The opening 12 is provided in the optical box 10 or the lid 101a, the transmission member 11 covers the opening 12 from the outside of the optical box 10, one long side from among two long sides is covered by one portion of the optical box 10 or the lid 101a, and the other long side from among the two long sides is fixed to the optical box 10 or the lid 101a.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a scanning optical device and an image forming device, and more particularly to a suitable shape for fixing a transmission member provided in a scanning optical device in an image forming device such as a laser beam printer or a digital copier having an electrophotographic process.

Background Art

[0002] A scanning optical device used in an image forming device employing an electrophotographic recording method such as a laser printer deflects and scans a laser beam emitted from a light source in accordance with an image signal by a light deflector such as a rotating polygon mirror, and transmits the laser beam through a scanning lens. Thereby, the spot formed on the surface of the photoreceptor is scanned, and a latent image is formed on the photoreceptor. The scanning optical device holds a light source, a light deflector, and a scanning lens in a housing. An opening is provided in the housing, and the laser beam is emitted from the opening to the outside of the housing. For example, as disclosed in Patent Document 1, in some scanning optical devices, a flat transmission member through which the laser beam can pass is fixed to an opening provided in the housing with a double-sided tape so that foreign substances such as dust and toner from the outside do not enter the inside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the conventional example has the following problems. When attaching the transmission member for dust prevention to the housing, both sides of the end face in the longitudinal direction of the flat plate are fixed to the housing with double-sided tape, resulting in poor assembly workability. In addition, since both sides of the end face in the longitudinal direction are fixed to the housing with double-sided tape, due to the difference in the linear expansion coefficients between the transmission member for dust prevention and the housing, there is a possibility that the double-sided tape peels off or the housing or the transmission member is deformed.

[0005] This invention was made under such circumstances, and aims to improve the ease of assembly when attaching the permeable member to the housing while maintaining dustproof performance, and to suppress deformation of the permeable member and housing due to the difference in the coefficient of thermal expansion between the permeable member and the housing. [Means for solving the problem]

[0006] To solve the above-mentioned problems, the present invention has the following configuration.

[0007] (1) A scanning optical device comprising: a light source that emits a beam of light; a deflector that deflects and scans the beam of light emitted from the light source; a lens through which the beam of light scanned by the deflector passes; a rectangular opening through which the beam of light that has passed through the lens passes; a rectangular transparent member that covers the opening and through which the beam of light passing through the opening passes; a housing that holds the light source, the deflector, the lens, and the transparent member; and a lid that closes the housing, wherein the beam of light is emitted to the outside from the transparent member, the opening is provided in the housing or the lid, the transparent member covers the opening from the outside of the housing, one of the two long sides is covered by a part of the housing or the lid, and the other of the two long sides is fixed to the housing or the lid Furthermore, when the transmissive member is defined as having one long side as the first long side and the other long side opposite to the first long side as the second long side, the housing or lid has a covering portion that covers the first long side, and the first long side is the upper long side in the vertical direction. A scanning optical device characterized by the following features.

[0008] (2) An image forming apparatus comprising: a scanning optical apparatus as described in (1); an image carrier on which an electrostatic latent image is formed by the scanning optical apparatus; a developing means for developing the electrostatic latent image with toner to form a toner image; a transfer means for transferring the toner image to a recording material; and a fixing means for fixing the toner image transferred by the transfer means. [Effects of the Invention]

[0009] According to the present invention, while maintaining dustproof performance, it is possible to improve the ease of assembly when attaching the permeable member to the housing, and to suppress deformation of the permeable member and the housing due to the difference in the coefficient of linear expansion between the permeable member and the housing. [Brief explanation of the drawing]

[0010] [Figure 1] Cross-sectional view showing the image forming apparatus of the embodiment. [Figure 2] Perspective view showing the scanning optical apparatus of the embodiment. [Figure 3] Perspective view showing the relationship between the opening and the double-sided tape used to fix the transparent member in the embodiment. [Figure 4] Cross-sectional view illustrating the configuration for fixing the transparent member to the optical box in the embodiment. [Figure 5] Cross-sectional view showing a modified example in which the shape of the covering portion of the embodiment has been changed. [Figure 6] A perspective view showing a modified example in which the shape near the opening of the optical box of the embodiment has been changed. [Modes for carrying out the invention] [Examples]

[0011] An image forming apparatus equipped with a scanning optical device according to an embodiment of the present invention will be described below. In the following description, an image forming apparatus equipped with a scanning optical device according to an embodiment of the present invention will be described as an example, and then the scanning optical device will be described in detail. In the following description, the direction in which the laser beam (light beam) scans the photosensitive drum (the axis of rotation of the photosensitive drum) will be referred to as the main scanning direction, and the direction in which the photosensitive drum rotates, perpendicular to the main scanning direction, will be referred to as the sub-scanning direction.

[0012] [Image forming apparatus] Figure 1 is a schematic cross-sectional view showing the image forming apparatus of this embodiment. The image forming apparatus 110 of this embodiment includes a scanning optical device 101. The scanning optical device 101 has an optical box 10, which will be described later, closed by a lid 101a. The image forming apparatus 110 also includes a process cartridge 102 and the like as image forming means, which scans a photosensitive drum 103, which serves as an image carrier, with a laser beam L emitted from the scanning optical device 101 based on input image information, and forms an image on a recording material P such as recording paper. Here, a printer will be used as an example to describe the image forming apparatus 110.

[0013] As shown in Figure 1, the image forming apparatus 110 (printer) emits a laser beam L based on the obtained image information using a scanning optical device 101 as an exposure means, and irradiates the photosensitive drum 103 of the process cartridge 102. An electrostatic latent image is then formed on the photosensitive drum 103, and this electrostatic latent image is developed by toner, which acts as a developer, by the process cartridge 102, and manifested as a toner image. The process cartridge 102 integrates the photosensitive drum 103 and process means that act on the photosensitive drum 103, such as a charging means and a developing means.

[0014] Meanwhile, the recording material P loaded on the loading plate 104 is fed one sheet at a time by the feeding roller 105, and then transported further downstream in the transport direction by the intermediate roller 106. The toner image formed on the photosensitive drum 103 is transferred onto the transported recording material P by the transfer roller 107, which acts as a transfer means. The recording material P on which this unfixed toner image has been formed is then transported further downstream, where it is heated and pressurized by the fuser 108, which acts as a fixing means, and the toner image is fixed to the recording material P. After that, the recording material P is discharged from the machine by the discharge roller 109.

[0015] In this embodiment, the charging means and developing means, which act on the photosensitive drum 103, are integrated with the photosensitive drum 103 in the process cartridge 102. However, each process means may be configured separately from the photosensitive drum 103. Furthermore, the image forming apparatus equipped with the scanning optical device of the present invention is not limited to the configuration shown in Figure 1.

[0016] [Scanning Optical Device] Next, the scanning optical device 101 in the image forming apparatus 110 will be described with reference to FIG. 2. The scanning optical device 101 includes a semiconductor laser unit 1, an anamorphic collimator lens 2, an aperture 3, a rotating polygon mirror 4, a deflecting device 5, a beam detector (hereinafter referred to as BD) 6, a control board 7, a signal transmission connector 8, an fθ lens 9, an optical box 10 as a housing, and a transmissive member 11. The semiconductor laser unit 1 emits a laser beam L. The anamorphic collimator lens 2 is a lens that integrates a collimator lens and a cylindrical lens. The aperture 3 shapes the laser beam L into a predetermined shape. The rotating polygon mirror 4 has a plurality (for example, four) of reflecting surfaces and deflects and scans the laser beam L. The deflecting device 5 (deflector) rotationally drives the rotating polygon mirror 4. The signal transmission connector 8 is provided on the control board 7. The fθ lens 9 is a scanning lens that guides the laser beam L reflected by the rotating polygon mirror 4 to the photosensitive drum 103.

[0017] In such a configuration, in response to an image signal received through the signal transmission connector 8 provided on the control board 7, the laser beam L is emitted from the semiconductor laser unit 1 as a light source. The laser beam L is converted by the anamorphic collimator lens 2 into parallel light or weakly convergent light in the main scanning direction and into convergent light in the sub-scanning direction. Next, the laser beam L is shaped into a predetermined shape by the aperture 3 and forms an image in a focal line shape that extends long in the main scanning direction on the reflecting surface of the rotating polygon mirror 4. Then, the laser beam L is deflected and scanned by rotating the rotating polygon mirror 4 and enters the BD 6 mounted on the control board 7. At this time, the BD 6 receives the laser beam L and outputs a signal (hereinafter also referred to as a synchronization signal or a BD signal), and this timing is set as the synchronization detection timing of the writing position in the main scanning direction.

[0018] Next, the laser beam is incident on the fθ lens 9. The fθ lens 9 is a lens designed to condense the laser beam L to form a spot on the photosensitive drum 103 and to keep the scanning speed of the spot constant. In order to obtain such characteristics of the fθ lens 9, the fθ lens 9 is formed of an aspherical lens. The laser beam L that has passed through the fθ lens 9 is image-scanned on the photosensitive drum 103 after passing through the transmission member 11 that covers the opening 12 (see FIG. 3) of the optical box 10. The scanning optical device 101 is closed by the lid 101a (see FIG. 1), the optical box 10, and the transmission member 11, thereby preventing foreign matter from entering the inside of the scanning optical device 101 that holds the fθ lens 9 and the like.

[0019] Note that the laser beam L is deflected and scanned by the rotation of the rotating polygon mirror 4, and the main scanning direction by the laser beam L is scanned on the photosensitive drum 103. Also, the photosensitive drum 103 is rotationally driven around the axis of the cylinder, thereby performing scanning in the sub-scanning direction. In this way, an electrostatic latent image is formed on the surface of the photosensitive drum 103. Note that FIG. 2 shows the main scanning direction Dm, which is the scanning direction of the laser beam L.

[0020] [Opening, Transmission Member] FIG. 3 is a diagram showing the relationship of the double-sided tape 14 as a fixing member for fixing the transmission member 11 covering the opening 12 of the optical box 10 and the optical box 10. For the sake of explanation, components other than the optical box 10 and the double-sided tape 14 are omitted.

[0021] The optical box 10 is provided with an opening 12 for emitting a laser beam L to the outside. The opening 12 is rectangular, and double-sided tape 14 is provided near the bottom surface of the opening 12. More specifically, the opening 12 is a long rectangle in the main scanning direction Dm. Of the two long sides of the rectangle of the opening 12, the long side closer to the lid 101a of the optical box 10 (see Figure 1) (the side further from the bottom surface of the optical box 10) is called long side 12a, and the long side closer to the bottom surface of the optical box 10 is called long side 12b. In this case, one side of the double-sided tape 14 is attached to the optical box 10 along long side 12b. In the main scanning direction Dm, the length of the long side 12b of the opening 12 is length L1, and the length of the double-sided tape 14 is length L2. In this embodiment, the length L2 of the double-sided tape 14 is set to be longer than the length L1 of the long side 12b of the opening 12 (L2 > L1).

[0022] Here, the transparent member 11 is also a long rectangle in the main scanning direction Dm, and the length of the transparent member 11 in the main scanning direction Dm is defined as length L3 (see Figure 2). In order to cover the entire opening 12, the length L3 of the transparent member 11 is set to be longer than the length L1 of the opening 12 (L3 > L1). Therefore, the entire longitudinal direction (main scanning direction Dm) of the transparent member 11 can be fixed by the double-sided tape 14, making it possible to more firmly fix the transparent member 11 to the optical box 10. Note that the length L2 of the double-sided tape 14 should be longer than the length L1 of the long side 12b of the opening 12, and preferably less than or equal to the length L3 of the transparent member 11 (L1 <L2≦L3)。

[0023] [Securing the transparent member] Figure 4 is a cross-sectional view illustrating the configuration for fixing the light-transmitting member 11 to the optical box 10, and is a cross-sectional view taken from the main scanning direction Dm. In Figure 4, the right side of the light-transmitting member 11 is the inside of the scanning optical device 101, and the left side is the outside. The light-transmitting member 11 covers the opening 12 from the outside. As explained in Figure 3, the optical box 10 is provided with an opening 12 for emitting the laser beam L to the outside. Here, of the two long sides of the light-transmitting member 11, one long side portion (one long side) is designated as the first long side and the first light-transmitting member end face 111, and the other long side portion (the other long side) is designated as the second long side and the second light-transmitting member end face 112. Also, the surface of the long side 12a portion of the opening 12 is designated as the first opening end face 121, and the surface of the long side 12b portion is designated as the second opening end face 122. Near the first opening end face 121 of the opening 12, a covering portion 13 is provided that covers the first light-transmitting member end face 111 of the light-transmitting member 11. In other words, a part of the optical box 10 is the covering portion 13.

[0024] In this embodiment, the shape of the covering portion 13 as viewed from the main scanning direction Dm is a U-shape in cross-section with a recess 13a. The recess 13a has surfaces 13a1, 13a2, and 13a3. Here, with the transparent member 11 fixed to the optical box 10, the surface of the transparent member 11 facing the opening 12, that is, the surface facing the inside of the optical box 10, is defined as surface 114 as the first surface. The surface opposite to surface 114 and facing the outside, that is, the surface facing the outside of the optical box 10, is defined as surface 113 as the second surface. Furthermore, for surfaces 113 and 114, the upper end (upper end) in the vertical direction is simply called the upper end, and the lower end in the vertical direction is simply called the lower end. With the transparent member 11 fixed to the optical box 10, the surface 13a1 of the recess 13a and the end surface 111 of the first transparent member are in contact, the surface 13a2 of the recess 13a and the upper end of the surface 113 of the transparent member 11 are facing each other, and the surface 13a3 of the recess 13a and the upper end of the surface 114 of the transparent member 11 are facing each other. Alternatively, the surface 13a2 of the recess 13a and the upper end of the surface 113 of the transparent member 11 may be in contact, or the surface 13a3 of the recess 13a and the upper end of the surface 114 of the transparent member 11 may be in contact.

[0025] A second opening end face 122 is provided at a position opposite to the first opening end face 121, and the first opening end face 121 is positioned vertically above the second opening end face 122. A second transparent member end face 112 is provided at a position on the long side opposite to the first transparent member end face 111, and the lower end of the surface 114 of the transparent member 11 that faces the optical box 10 near the second transparent member end face 112 is fixed to the optical box 10 by double-sided tape 14. In this embodiment, double-sided tape 14 is used as a fixing member to fix the transparent member 11 to the optical box 10, but for fixing purposes, for example, UV adhesive or the like may be used as a fixing member.

[0026] The first transparent member end face 111 of the transparent member 11 is covered on its long side by a covering portion 13 relative to the optical box 10. As described above, the covering portion 13 has a U-shaped cross-section, and there is a gap between the transparent member 11 and the covering portion 13. In this embodiment, the thickness D1 of the transparent member 11 is set to 1.8 mm, and the cross-sectional dimension of the covering portion 13 (D2 in Figure 4; the length in the width direction of the recess 13a) is set to 2 mm (D2 > D1). Note that the thickness is the length in the width direction when the direction perpendicular to the longitudinal and short directions of the transparent member 11 is defined as the width direction. By setting it so as to cover the first transparent member end face 111 in this way, it is possible to reduce the intrusion of foreign matter into the optical box 10 from vertically above through the transparent member 11 and the opening 12, even without fixing the long side (upper end side). Furthermore, since the transparent member 11 is fixed to the optical box 10 by attaching only one of its longer sides (the lower end), it is possible to reduce the amount of work required for attachment.

[0027] [Materials for transparent components and optical boxes] In this embodiment, glass was used as the material for the permeable member 11. The Young's modulus of the glass is 69000 (MPa), and the coefficient of linear expansion is 9 × 10⁻⁶. -6 The temperature is ( / °C). On the other hand, the optical box 10 and lid 101a are made of resin, and the material used is PC+AS resin with 20% filler. The Young's modulus of the PC+AS resin with 20% filler is 5000 (MPa), and the coefficient of linear expansion is 45 × 10⁻⁶. -6( / °C). In other words, the coefficient of linear expansion of the transparent member 11 is smaller than the coefficient of linear expansion of the optical box 10.

[0028] The PC+AS resin containing 20% ​​filler has a coefficient of thermal expansion five times that of glass, and the amount of deformation of the resin due to temperature changes between manufacturing and use is five times greater. Since the first opening end face 121 is not fixed to the transparent member 11, it is not affected by temperature changes. Therefore, the influence on the optical box 10 when the transparent member 11 is attached to the optical box 10 is reduced.

[0029] Furthermore, the Young's modulus of glass is approximately 14 times greater than that of PC+AS resin with 20% filler. Therefore, the strain caused by thermal deformation of the glass transmission member 11 and the optical box 10 is not significantly generated in the transmission member 11, but rather absorbed by the optical box 10.

[0030] [Example 1] In the embodiment described above, glass is used as the material for the transparent member 11. Modification 1 describes a case where, for example, the material is changed to a lower-cost transparent polycarbonate resin. The coefficient of linear expansion of polycarbonate resin is 65 × 10⁻⁶. -6 The temperature is (°C / °C), and the Young's modulus is 2200 (MPa). The polycarbonate resin permeable member 11 has a higher coefficient of linear expansion and a lower Young's modulus than the PC+AS resin with 20% filler used in the optical box 10. When a resin with such characteristics is used as a permeable member for dustproofing, it becomes more susceptible to thermal deformation than the optical box 10. Therefore, instead of fixing both ends (the two long sides) of the permeable member 11, only one of the two long sides is fixed to the optical box 10. This makes it possible to reduce the effect of thermal deformation on the permeable member 11.

[0031] [Differentiation 2] Figure 5 shows a modified example 2 in which the shape of the covering portion 13A is changed. In the configuration shown in Figure 4, the cross-sectional dimensions of the covering portion 13 were constant on the insertion side and the insertion side in the insertion direction Di. Here, the insertion direction Di refers to the direction in which the transparent member 11 is inserted into the covering portion 13, and is illustrated by an arrow in Figure 5. In contrast, in the configuration shown in Figure 5, the cross-sectional dimensions on the insertion side in the insertion direction Di are 2.5 mm (D3), and the cross-sectional dimensions on the insertion side are 2 mm (D4), so that the cross-sectional dimensions on the insertion side are wider than the cross-sectional dimensions on the insertion side (D3 > D4). In other words, the length of the covering portion 13A in the width direction decreases towards the insertion direction Di in which the transparent member 11 is inserted. To put it another way, the surface 13b2 facing surface 113 of the covering portion 13A is inclined.

[0032] Specifically, the covering portion 13A has a recess 13b. The shape of the covering portion 13A as viewed from the main scanning direction Dm is a trapezoidal cross-section with a recess 13b. The recess 13b has surfaces 13b1, 13b2, and 13b3. With the transparent member 11 fixed to the optical box 10, surface 13b1 of the recess 13b and the end surface 111 of the first transparent member abut, surface 13b2 of the recess 13b and the upper end of surface 113 of the transparent member 11 face each other, and surface 13b3 of the recess 13b and the upper end of surface 114 of the transparent member 11 face each other. Alternatively, surface 13b3 of the recess 13b and the upper end of surface 114 of the transparent member 11 may abut. For the covering portion 13A, the length on the entrance side in the insertion direction Di, in the direction perpendicular to the main scanning direction Dm and the insertion direction Di, is defined as length D3, and the length of surface 13b1 is defined as length D4. Therefore, length D3 is longer than length D4 (D3 > D4).

[0033] The transparent member 11 is inserted into the covering portion 13A from near the opening 12, but the transparent member 11 can be inserted at an angle relative to the covering portion 13A. More specifically, when inserting the transparent member 11 into the covering portion 13A in the insertion direction Di, the corner portion 111a of the first transparent member end face 111 of the transparent member 11 is moved along the surface 13b2 of the covering portion 13A. This allows the transparent member 11 to be inserted into the covering portion 13A at an angle. With this configuration, it is possible to further improve the workability when assembling the transparent member 11 to the optical box 10 while maintaining dustproof performance against foreign matter entering the optical box 10 through the opening 12.

[0034] [Difference 3] Figure 6 shows a modified example 3 in which the shape near the opening 12 of the optical box 10 is changed. The optical box 10 has a rib 15 extending in the short direction (vertical direction) of the transparent member 11 at at least one end of the covering portion 13A in the longitudinal direction of the transparent member 11. Here, the optical box 10 has ribs 15 near each of the two short sides of the transparent member 11. The ribs 15 are provided near the short sides of the transparent member 11, approximately parallel to both short sides of the transparent member 11, and with a length equivalent to the length of both short sides of the transparent member 11. In modified example 3 of Figure 6, the rib 15 is formed integrally with the covering portion 13A and has a shape that extends vertically downward from the covering portion 13A. Here, in the vertical direction (short direction of the transparent member 11), the length of the rib 15 and the covering portion 13A is length L4, and the length of the transparent member 11 is length L5 (see Figure 5). In this case, the rib 15 is provided such that the length L4 of the rib 15 and the covering portion 13A is greater than or equal to the length L5 of the permeable member 11 (L4≧L5).

[0035] As shown in Figure 6, by providing a rib 15 on the optical box 10 near the short side of the transparent member 11 that corresponds to the short side, it is possible to further reduce the intrusion of foreign matter into the optical box 10 through the opening 12 from the gap between the end face on the short side of the transparent member 11 and the optical box 10. The rib 15 may be combined with either the covering portion 13 in Figure 4 or the covering portion 13A in Figure 5.

[0036] Furthermore, although the transparent member 11 is fixed to the optical box 10 in this embodiment, the invention is not limited to this. An opening 12 for emitting the laser beam L from inside the optical box 10 to the outside may be provided in the lid 101a (see Figure 1) for closing the optical box 10. In this case, the same effect can be obtained by providing covering portions 13, 13A and ribs 15 on the lid 101a. That is, the lid 101a may have covering portions 13, 13A, and the lid 101a may also have ribs 15. Furthermore, in the above-described embodiment, the covering portions 13 and 13A were provided on the upper side in the vertical direction and the double-sided tape 14 was attached to the lower side in the vertical direction. However, the double-sided tape 14 may be attached to the upper side in the vertical direction and the covering portions 13 and 13A may be provided on the lower side in the vertical direction.

[0037] As described above, according to the embodiment, it is possible to improve the ease of assembly when attaching the permeable member to the housing while maintaining dustproof performance, and to suppress deformation of the permeable member and housing due to the difference in the coefficient of thermal expansion between the permeable member and the housing.

[0038] This embodiment includes the following configuration. (Composition 1) A light source that emits a beam of light, A deflector that deflects and scans the light beam emitted from the aforementioned light source, A lens through which the light beam scanned by the deflector passes, A rectangular aperture through which the light beam that has passed through the lens passes, A rectangular transmissive member that covers the opening and through which the light beam passing through the opening is transmitted, The light source, the deflector, the lens, and the housing that holds the transparent member, A lid that closes the aforementioned housing, A scanning optical device comprising, wherein the light beam is emitted to the outside from the transmitting member, The opening is provided in the housing or the lid, The scanning optical apparatus is characterized in that the transparent member covers the opening from the outside of the housing, one of the two long sides is covered by a part of the housing or the lid, and the other of the two long sides is fixed to the housing or the lid. (Configuration 2) With respect to the transparent member, when one of the longer sides is designated as the first longer side, and the other longer side opposite to the first longer side is designated as the second longer side, The housing or the lid has a covering portion that covers the first long side, The scanning optical apparatus according to configuration 1, characterized in that the first long side is the upper long side in the vertical direction. (Composition 3) When the direction perpendicular to the longitudinal and transverse directions of the aforementioned transparent member is defined as the width direction, The covering portion has a recess that has a U-shaped cross-section when viewed from the longitudinal direction. The scanning optical apparatus according to configuration 2, characterized in that the length of the recess in the width direction is longer than the length of the transparent member in the width direction. (Composition 4) When the direction perpendicular to the longitudinal and transverse directions of the aforementioned transparent member is defined as the width direction, The scanning optical apparatus according to configuration 2, characterized in that the covering portion has a recess in which the length in the width direction becomes shorter in the insertion direction into which the transparent member is inserted. (Composition 5) With the transparent member fixed to the housing or the lid, the surface of the transparent member facing the opening is designated as the first surface, and the surface opposite to the first surface and facing the outside is designated as the second surface, The scanning optical apparatus according to configuration 4, characterized in that the surface of the covering portion facing the second surface is inclined. (Composition 6) The scanning optical apparatus according to any one of configurations 2 to 5, characterized in that the housing or the lid has a rib extending in the short direction of the transparent member at at least one end of the covering portion in the longitudinal direction of the transparent member. (Composition 7) The scanning optical apparatus according to any one of configurations 2 to 6, characterized in that the covering portion is longer than the length of the transparent member in the longitudinal direction of the transparent member. (Composition 8) The other long side of the transparent member has a fixing member that secures it to the housing or the lid, The scanning optical apparatus according to any one of configurations 1 to 7, characterized in that the fixing member is longer than the length of the aperture in the longitudinal direction of the transparent member. (Composition 9) The aforementioned transparent member is glass, The housing or the lid is made of resin, A scanning optical apparatus according to any one of configurations 1 to 8, characterized in that the coefficient of linear expansion of the transparent member is smaller than the coefficient of linear expansion of the housing or the lid. (Composition 10) The transparent member and the housing or lid are made of resin. The scanning optical apparatus according to any one of configurations 1 to 8, characterized in that the coefficient of linear expansion of the transparent member is greater than the coefficient of linear expansion of the housing or the lid. (Composition 11) A scanning optical apparatus as described in any of configurations 1 to 10, An image carrier on which an electrostatic latent image is formed by the scanning optical device, A developing means for developing the electrostatic latent image with toner to form a toner image, A transfer means for transferring the toner image onto a recording material, Fixing means for fixing the toner image transferred by the transfer means, An image forming apparatus characterized by comprising: [Explanation of symbols]

[0039] 1. Semiconductor laser unit 5 Deflection device 9 fθ lens 10 optical box 11. Permeable member 12 aperture 101 Scanning Optical System 101a Lid

Claims

1. A light source that emits a beam of light, A deflector that deflects and scans the light beam emitted from the aforementioned light source, A lens through which the light beam scanned by the deflector passes, A rectangular aperture through which the light beam that has passed through the lens passes, A rectangular transmissive member that covers the opening and through which the light beam passing through the opening is transmitted, The light source, the deflector, the lens, and the housing that holds the transparent member, A lid that closes the aforementioned housing, A scanning optical device comprising, wherein the light beam is emitted to the outside from the transmitting member, The opening is provided in the housing or the lid, The transparent member covers the opening from the outside of the housing, with one of its two long sides covered by a part of the housing or the lid, and the other of its two long sides fixed to the housing or the lid. With respect to the transparent member, when one of the longer sides is designated as the first longer side, and the other longer side opposite to the first longer side is designated as the second longer side, The housing or the lid has a covering portion that covers the first long side, A scanning optical apparatus characterized in that the first long side is the upper long side in the vertical direction.

2. When the direction perpendicular to the longitudinal and transverse directions of the aforementioned transparent member is defined as the width direction, The covering portion has a recess that has a U-shaped cross-section when viewed from the longitudinal direction. The scanning optical apparatus according to claim 1, characterized in that the length of the recess in the width direction is longer than the length of the transparent member in the width direction.

3. When the direction perpendicular to the longitudinal and transverse directions of the aforementioned transparent member is defined as the width direction, The scanning optical apparatus according to claim 1, characterized in that the covering portion has a recess in which the length in the width direction becomes shorter in the insertion direction into which the transparent member is inserted.

4. With the transparent member fixed to the housing or the lid, the surface of the transparent member facing the opening is designated as the first surface, and the surface opposite to the first surface and facing the outside is designated as the second surface, The scanning optical apparatus according to claim 3, characterized in that the surface of the covering portion facing the second surface is inclined.

5. The scanning optical apparatus according to claim 1, characterized in that the housing or the lid has a rib extending in the short direction of the transparent member at at least one end of the covering portion in the longitudinal direction of the transparent member.

6. The scanning optical apparatus according to claim 1, characterized in that the covering portion is longer than the length of the transparent member in the longitudinal direction of the transparent member.

7. The other long side of the transparent member has a fixing member that secures it to the housing or the lid, The scanning optical apparatus according to claim 1, characterized in that the fixing member is longer than the length of the aperture in the longitudinal direction of the transparent member.

8. The aforementioned transparent member is glass, The housing or the lid is made of resin, The scanning optical apparatus according to claim 1, characterized in that the coefficient of linear expansion of the transparent member is smaller than the coefficient of linear expansion of the housing or the lid.

9. The transparent member and the housing or lid are made of resin. The scanning optical apparatus according to claim 1, characterized in that the coefficient of linear expansion of the transparent member is greater than the coefficient of linear expansion of the housing or the lid.

10. A scanning optical apparatus according to any one of claims 1 to 9, An image carrier on which an electrostatic latent image is formed by the scanning optical device, A developing means for developing the electrostatic latent image with toner to form a toner image, A transfer means for transferring the toner image onto a recording material, Fixing means for fixing the toner image transferred by the transfer means, An image forming apparatus characterized by comprising:

Images