Scanning optical device and image-forming device

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 apparatus, and more particularly to a shape suitable for fixing a transparent member provided in a scanning optical device in an image forming apparatus such as a laser beam printer or a digital copier using an electrophotographic process. [Background technology]

[0002] A scanning optical device used in an electrophotographic image forming device such as a laser printer deflects a laser beam emitted from a light source in response to an image signal using an optical deflector such as a rotating polygon mirror, and transmits the beam through a scanning lens. This scans a spot formed on the surface of a photosensitive member, forming a latent image on the photosensitive member. The scanning optical device holds the light source, optical deflector, and scanning lens within a housing, and the housing has an opening through which the laser beam is emitted to the outside of the housing. For example, as disclosed in Patent Document 1, some scanning optical devices have a flat, transparent member that allows the laser beam to pass through the opening in the housing, fixed with double-sided tape to prevent foreign matter such as dust and toner from entering the device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-145916 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional example has the following problems: When attaching the dustproof transparent member to the housing, two longitudinal end faces of the flat plate are fixed to the housing with double-sided tape, which makes assembly work difficult. Furthermore, because two longitudinal end faces are fixed to the housing with double-sided tape, there is a possibility that the double-sided tape will peel off or that the housing or the dustproof transparent member will deform due to the difference in linear expansion coefficient between the dustproof transparent member and the housing.

[0005] The present invention was made under these circumstances, and aims to improve the assembly workability when attaching a transparent member to a housing while maintaining dustproof performance, and to suppress deformation of the transparent member and the housing due to differences in the linear expansion coefficients of the transparent member and the housing. [Means for solving the problem]

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

[0007] (1) A scanning optical device comprising: a light source that irradiates a light beam; a deflector that deflects and scans the light beam irradiated from the light source; a lens through which the light beam scanned by the deflector passes; a rectangular opening through which the light beam that has passed through the lens passes; a rectangular transparent member that covers the opening and through which the light beam that passes 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 light beam is emitted to the outside from the transparent member, wherein the opening is provided in the housing or the lid, the transparent member covers the opening from the outside of the housing, one of two long sides is covered by a part of the housing or the lid, and the other long side of the two long sides is fixed to the housing or the lid.

[0008] (2) An image forming apparatus comprising: a scanning optical device according to (1); 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; and a fixing means for fixing the toner image transferred by the transfer means. [Effects of the Invention]

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

[0010] [Figure 1] 1 is a cross-sectional view showing an image forming apparatus according to an embodiment of the present invention; [Figure 2] FIG. 1 is a perspective view showing a scanning optical device according to an embodiment of the present invention; [Figure 3] FIG. 10 is a perspective view showing the relationship between the opening and the double-sided tape for fixing the transparent member in the embodiment. [Figure 4] FIG. 10 is a cross-sectional view illustrating a configuration for fixing a transparent member to an optical box according to an embodiment. [Figure 5] 10 is a cross-sectional view showing a modified example in which the shape of the covering portion of the embodiment is changed. [Figure 6] FIG. 10 is a perspective view showing a modified example in which the shape of the vicinity of the opening of the optical box of the embodiment is changed. DETAILED DESCRIPTION OF THE INVENTION [Example]

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

[0012] [Image forming equipment] 1 is a schematic cross-sectional view showing an image forming apparatus of this embodiment. The image forming apparatus 110 of this embodiment includes a scanning optical device 101. Note that 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 that 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 described as an example of the image forming apparatus 110.

[0013] As shown in Fig. 1, an image forming apparatus 110 (printer) emits a laser beam L based on obtained image information from a scanning optical device 101 serving as an exposure means, and irradiates the laser beam L onto a photosensitive drum 103 provided in a process cartridge 102. An electrostatic latent image is then formed on the photosensitive drum 103, and the electrostatic latent image is developed by the process cartridge 102 with toner serving as a developer, to become a visible toner image. The process cartridge 102 integrally includes the photosensitive drum 103 and, as process means acting on the photosensitive drum 103, charging means, developing means, etc.

[0014] Meanwhile, recording materials P stacked on a stacking plate 104 are fed while being separated one sheet at a time by a feeding roller 105, and then conveyed further downstream in the conveying direction by an intermediate roller 106. A toner image formed on a photosensitive drum 103 is transferred onto the conveyed recording material P by a transfer roller 107 serving as a transfer means. The recording material P with this unfixed toner image formed thereon is conveyed further downstream and heated and pressurized by a fixing device 108 serving as a fixing means, so that the toner image is fixed to the recording material P. Thereafter, the recording material P is discharged out of the apparatus by a discharge roller 109.

[0015] In this embodiment, the charging means and developing means as process means acting on the photosensitive drum 103 are integrally provided with the photosensitive drum 103 in the process cartridge 102, but each process means may be configured separately from the photosensitive drum 103. Also, the image forming apparatus equipped with the scanning optical device of the present invention is not limited to the configuration shown in FIG.

[0016] [Scanning optical device] Next, a scanning optical device 101 in an 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 deflection 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 serving as a housing, and a transparent 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 multiple (e.g., four) reflecting surfaces and deflects and scans the laser beam L. The deflection device 5 (deflector) rotates 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 rotary polygon mirror 4 onto the photosensitive drum 103 .

[0017] In this configuration, a laser beam L is emitted from a semiconductor laser unit 1 serving as a light source in response to an image signal received through a signal transmission connector 8 provided on a control board 7. The laser beam L is converted by an 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. The laser beam L is then shaped into a predetermined shape by an aperture 3 and forms an image on the reflecting surface of a rotating polygon mirror 4 as a focal line extending long in the main scanning direction. The laser beam L is then deflected and scanned by rotating the rotating polygon mirror 4, and is incident on a 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 BD signal), the timing of which is used to synchronize and detect the writing start position in the main scanning direction.

[0018] Next, the laser beam enters the fθ lens 9. The fθ lens 9 is designed to focus the laser beam L to form a spot on the photosensitive drum 103 and to maintain a constant scanning speed of the spot. To obtain such characteristics of the fθ lens 9, the fθ lens 9 is formed of an aspherical lens. The laser beam L passing through the fθ lens 9 passes through the optical box 10 and the transparent member 11 that covers the opening 12 (see FIG. 3), and is then imaged and scanned onto the photosensitive drum 103. The scanning optical device 101 is closed by the cover 101a (see FIG. 1), the optical box 10, and the transparent member 11, thereby preventing foreign matter from entering the interior of the scanning optical device 101, which holds the fθ lens 9 and other components.

[0019] The laser beam L is deflected and scanned by the rotation of the rotary polygon mirror 4, and scanning in the main scanning direction by the laser beam L occurs on the photosensitive drum 103. The photosensitive drum 103 is also rotated about its cylindrical axis to perform scanning in the sub-scanning direction. In this way, an electrostatic latent image is formed on the surface of the photosensitive drum 103. In FIG. 2, the main scanning direction, which is the scanning direction of the laser beam L, is indicated as Dm.

[0020] [Openings, transparent materials] 3 is a diagram showing the relationship between the transparent member 11 covering the opening 12 of the optical box 10 and the double-sided tape 14 serving as a fixing member for fixing the optical box 10. For the sake of explanation, parts other than the optical box 10 and the double-sided tape 14 are omitted.

[0021] The optical box 10 has an opening 12 for emitting the laser beam L to the outside. The opening 12 has a rectangular shape, and double-sided tape 14 is provided near the bottom surface of the opening 12. More specifically, the opening 12 has a rectangular shape that is long 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 (see FIG. 1) of the optical box 10 (the side farther from the bottom surface of the optical box 10) is referred to as long side 12a, and the long side closer to the bottom surface of the optical box 10 is referred to as long side 12b. One side of the double-sided tape 14 is attached to the optical box 10 along the long side 12b on the side of the long side 12b. In addition, the length of the long side 12b of the opening 12 in the main scanning direction Dm is referred to as length L1, and the length of the double-sided tape 14 is referred to as 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 also has a rectangular shape that is long in the main scanning direction Dm, and the length of the transparent member 11 in the main scanning direction Dm is defined as a length L3 (see FIG. 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 area of ​​the transparent member 11 in the longitudinal direction (main scanning direction Dm) can be fixed with the double-sided tape 14, which makes 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 is longer than the length L1 of the long side 12b of the opening 12, and is preferably equal to or shorter than the length L3 of the transparent member 11 (L1 <L2≦L3)。

[0023] [Fixing transparent members] FIG. 4 is a cross-sectional view illustrating a configuration for fixing the transparent member 11 to the optical box 10, as viewed from the main scanning direction Dm. In FIG. 4, the right side of the transparent member 11 is the interior of the scanning optical device 101, and the left side is the exterior. The transparent member 11 covers the opening 12 from the exterior side. As described with reference to FIG. 3, the optical box 10 is provided with an opening 12 for emitting the laser light beam L to the exterior. Here, of the two long sides of the transparent member 11, one long side (one long side) is referred to as a first long side and a first transparent member end surface 111, and the other long side (the other long side) is referred to as a second long side and a second transparent member end surface 112. Furthermore, the surface of the long side 12a of the opening 12 is referred to as a first opening end surface 121, and the surface of the long side 12b is referred to as a second opening end surface 122. A covering portion 13 is provided near the first opening end surface 121 of the opening 12 to cover the first transparent member end surface 111 of the transparent member 11. That is, a part of the optical box 10 serves as 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-shaped cross section having the recess 13a. The recess 13a has surfaces 13a1, 13a2, and 13a3. Here, when the transparent member 11 is fixed to the optical box 10, the surface facing the opening 12 of the transparent member 11, i.e., the surface facing the inside of the optical box 10, is referred to as surface 114 as a first surface. Furthermore, the surface opposite surface 114 facing the outside, i.e., the surface facing the outside of the optical box 10, is referred to as surface 113 as a second surface. Furthermore, with respect to surfaces 113 and 114, the upper end portions (upper ends) in the vertical direction are simply referred to as upper ends, and the lower end portions in the vertical direction are simply referred to as lower ends. In a state in which the transparent member 11 is fixed to the optical box 10, the surface 13a1 of the recess 13a abuts against the end surface 111 of the first transparent member, the surface 13a2 of the recess 13a faces the upper end of the surface 113 of the transparent member 11, and the surface 13a3 of the recess 13a faces the upper end of the surface 114 of the transparent member 11. Note that the surface 13a2 of the recess 13a may abut against the upper end of the surface 113 of the transparent member 11, or the surface 13a3 of the recess 13a may abut against the upper end of the surface 114 of the transparent member 11.

[0025] A second opening end face 122 is provided at a position facing the first opening end face 121, and the first opening end face 121 is positioned vertically higher than the second opening end face 122. A second transparent member end face 112 is provided at a long side position facing the first transparent member end face 111, and a lower end of a 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 with double-sided tape 14. In this embodiment, the double-sided tape 14 is used as a fixing member for fixing the transparent member 11 to the optical box 10, but for example, a UV adhesive or the like may also be used as the fixing member for fixing.

[0026] The long side of the first transparent member end surface 111 of the transparent member 11 is covered with the covering portion 13 relative to the optical box 10. As described above, the cross section of the covering portion 13 has a U-shape, 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 FIG. 4; the width direction length of the recess 13a) is set to 2 mm (D2>D1). Note that the thickness refers to the length in the width direction when the direction perpendicular to the longitudinal and lateral directions of the transparent member 11 is defined as the width direction. By setting the first transparent member end surface 111 to cover in this way, it is possible to reduce the intrusion of foreign matter into the optical box 10 from above in the vertical direction through the transparent member 11 and the opening 12, even if the long side (upper end side) is not fixed. Furthermore, when the transparent member 11 is fixed to the optical box 10, only one of the long sides (the lower end side) is attached, which also makes it possible to reduce the number of steps required for attachment.

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

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

[0029] Furthermore, the Young's modulus of glass is approximately 14 times greater than that of PC+AS resin containing 20% ​​filler. Therefore, strain caused by thermal deformation of the glass transparent member 11 and optical box 10 does not occur much in the transparent member 11, and the strain caused by thermal deformation is absorbed by the optical box 10.

[0030] [Variation 1] In the above-described embodiment, glass is used as the material of the transparent member 11. In Modification 1, a case where the material is changed to, for example, a low-cost transparent polycarbonate resin will be described. The linear expansion coefficient of polycarbonate resin is 65×10 -6 ( / °C) and a Young's modulus of 2200 (MPa). The transparent member 11 made of polycarbonate resin has a larger linear expansion coefficient and a smaller Young's modulus than the PC+AS resin containing 20% ​​filler used in the optical box 10. If a resin with such properties is used as a dustproof transparent member, it will be more susceptible to thermal deformation than the optical box 10. For this reason, both ends (two long sides) of the transparent member 11 are not fixed, and 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 transparent member 11.

[0031] [Variation 2] FIG. 5 is a diagram showing a second modification in which the shape of the covering portion 13A is changed. In the configuration shown in FIG. 4, the cross-sectional dimensions of the covering portion 13 were constant on the insertion opening side and the insertion depth 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 indicated by an arrow in FIG. 5. In contrast, in the configuration shown in FIG. 5, the cross-sectional dimension on the insertion opening side in the insertion direction Di is 2.5 mm (D3), and the cross-sectional dimension on the insertion depth side is 2 mm (D4), so that the cross-sectional dimension on the insertion opening side is wider than the cross-sectional dimension on the insertion depth side (D3>D4). That is, the covering portion 13A has a shorter length in the width direction toward the insertion direction Di in which the transparent member 11 is inserted. In other words, the covering portion 13A has an inclined surface 13b2 facing the surface 113.

[0032] Specifically, the covering portion 13A has a recess 13b. The covering portion 13A has a trapezoidal cross section with the recess 13b when viewed from the main scanning direction Dm. The recess 13b has surfaces 13b1, 13b2, and 13b3. When the transparent member 11 is fixed to the optical box 10, the surface 13b1 of the recess 13b abuts against the first transparent member end surface 111, the surface 13b2 of the recess 13b faces the upper end of the surface 113 of the transparent member 11, and the surface 13b3 of the recess 13b faces the upper end of the surface 114 of the transparent member 11. The surface 13b3 of the recess 13b may abut against the upper end of the surface 114 of the transparent member 11. Regarding the covering portion 13A, the length of the entrance side in the insertion direction Di, which is a direction perpendicular to the main scanning direction Dm and the insertion direction Di, is defined as length D3, and the length of the surface 13b1 is defined as length D4. In this case, the length D3 is longer than the length D4 (D3>D4).

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

[0034] [Variation 3] FIG. 6 is a diagram showing a third modification in which the shape of the vicinity of the opening 12 of the optical box 10 is changed. The optical box 10 has a rib 15 extending in the short-side 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 a rib 15 near each of the two short sides of the transparent member 11. The rib 15 is provided near the short sides of the transparent member 11, approximately parallel to both short sides of the transparent member 11, and has a length equivalent to the length of both short sides of the transparent member 11. In the third modification in FIG. 6, the rib 15 is formed integrally with the covering portion 13A and extends vertically downward from the covering portion 13A. Here, the length of the rib 15 and the covering portion 13A in the vertical direction (short-side direction of the transparent member 11) is length L4, and the length of the transparent member 11 is length L5 (see FIG. 5). In this case, the rib 15 is provided so that the length L4 of the rib 15 and the covering portion 13A is equal to or greater than the length L5 of the transmitting member 11 (L4≧L5).

[0035] 6, by providing the optical box 10 with ribs 15 corresponding to the short sides near the short sides of the transparent member 11, 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 ribs 15 may be combined with either the covering portion 13 in FIG. 4 or the covering portion 13A in FIG. 5.

[0036] Furthermore, in this embodiment, the transparent member 11 is fixed to the optical box 10, but this is not limiting. The opening 12 through which the laser light beam L is emitted from inside the optical box 10 to the outside may be provided in the lid 101a (see FIG. 1) for closing the optical box 10. In this case, the same effect can be obtained even if the covering portions 13, 13A and the rib 15 are provided on the lid 101a. That is, the lid 101a may have the covering portions 13, 13A, and the lid 101a may also have the rib 15. In addition, in the above-described embodiment, the covering portions 13, 13A are provided on the upper side in the vertical direction and the double-sided tape 14 is attached on the lower side in the vertical direction, but the double-sided tape 14 may be attached on the upper side in the vertical direction and the covering portions 13, 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 assembly workability when attaching the transparent member to the housing while maintaining dustproof performance, and also to suppress deformation of the transparent member and the housing due to the difference in linear expansion coefficient between the transparent member and the housing.

[0038] The disclosure of this embodiment includes the following configuration. (Configuration 1) a light source that emits a light beam; a deflector that deflects and scans the light beam emitted from the light source; a lens through which the light beam scanned by the deflector passes; a rectangular opening through which the light beam passing through the lens passes; a rectangular transparent member that covers the opening and transmits the light beam that passes through the opening; a housing that holds the light source, the deflector, the lens, and the transparent member; a lid that closes the housing; wherein the light beam 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 long side is fixed to the housing or the lid. (Configuration 2) Regarding the transparent member, when the one long side is defined as a first long side and the other long side opposite to the first long side is defined as a second long side, the housing or the lid has a covering portion that covers the first long side, 2. The scanning optical device according to configuration 1, wherein the first long side is an upper long side in the vertical direction. (Configuration 3) When the direction perpendicular to the longitudinal direction and the lateral direction of the transmitting member is defined as the width direction, the covering portion has a recess having a U-shaped cross section when viewed from the longitudinal direction, 3. The scanning optical device according to configuration 2, wherein the length of the recess in the width direction is longer than the length of the transmissive member in the width direction. (Configuration 4) When the direction perpendicular to the longitudinal direction and the lateral direction of the transmitting member is defined as the width direction, 3. The scanning optical device according to configuration 2, wherein the covering portion has a recess whose length in the width direction decreases toward an insertion direction in which the transparent member is inserted. (Configuration 5) When the transparent member is fixed to the housing or the lid, a surface of the transparent member facing the opening is defined as a first surface, and a surface opposite to the first surface and facing the outside is defined as a second surface, 5. The scanning optical device according to configuration 4, wherein the covering portion has an inclined surface facing the second surface. (Configuration 6) 6. The scanning optical device according to any one of configurations 2 to 5, wherein 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. (Configuration 7) 7. The scanning optical device according to any one of configurations 2 to 6, wherein the covering portion is longer than the length of the transparent member in the longitudinal direction of the transparent member. (Configuration 8) a fixing member that fixes the other long side of the transparent member to the housing or the lid; 8. The scanning optical device according to any one of configurations 1 to 7, wherein the fixing member is longer than the length of the opening in the longitudinal direction of the transparent member. (Configuration 9) the transparent member is glass, the housing or the lid is made of resin, 9. The scanning optical device according to any one of configurations 1 to 8, wherein the linear expansion coefficient of the transparent member is smaller than the linear expansion coefficient of the housing or the lid. (Configuration 10) the transparent member and the housing or the lid are made of resin, 9. The scanning optical device according to any one of configurations 1 to 8, wherein the linear expansion coefficient of the transparent member is greater than the linear expansion coefficient of the housing or the lid. (Configuration 11) a scanning optical device according to any one of configurations 1 to 10; and 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; a fixing unit for fixing the toner image transferred by the transfer unit; An image forming apparatus comprising: [Explanation of symbols]

[0039] 1 Semiconductor laser unit 5 Deflection device 9 fθ lenses 10 optical box 11 Transparent member 12 Aperture 101 Scanning optical device 101a Lid

Claims

1. a light source that emits a light beam; a deflector that deflects and scans the light beam emitted from the light source; a lens through which the light beam scanned by the deflector passes; a rectangular opening through which the light beam passing through the lens passes; a rectangular transparent member that covers the opening and transmits the light beam that passes through the opening; a housing that holds the light source, the deflector, the lens, and the transparent member; a lid that closes the housing; wherein the light beam 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 long side is fixed to the housing or the lid.

2. Regarding the transparent member, when the one long side is defined as a first long side and the other long side opposite to the first long side is defined as a second long side, the housing or the lid has a covering portion that covers the first long side, 2. The scanning optical device according to claim 1, wherein the first long side is an upper long side in the vertical direction.

3. When the direction perpendicular to the longitudinal direction and the lateral direction of the transmitting member is defined as the width direction, the covering portion has a recess having a U-shaped cross section when viewed from the longitudinal direction, 3. The scanning optical device according to claim 2, wherein the length of the recess in the width direction is longer than the length of the transmissive member in the width direction.

4. When the direction perpendicular to the longitudinal direction and the lateral direction of the transmitting member is defined as the width direction, 3. The scanning optical device according to claim 2, wherein the covering portion has a recess whose length in the width direction decreases toward an insertion direction in which the transparent member is inserted.

5. When the transparent member is fixed to the housing or the lid, a surface of the transparent member facing the opening is defined as a first surface, and a surface opposite to the first surface and facing the outside is defined as a second surface, 5. The scanning optical device according to claim 4, wherein the covering portion has a surface that faces the second surface and is inclined.

6. 3. The scanning optical device according to claim 2, wherein the housing or the cover has a rib extending in a lateral direction of the transparent member at at least one end of the covering portion in the longitudinal direction of the transparent member.

7. 3. The scanning optical device according to claim 2, wherein the covering portion is longer than the length of the transmitting member in the longitudinal direction of the transmitting member.

8. a fixing member that fixes the other long side of the transparent member to the housing or the lid; 2. The scanning optical device according to claim 1, wherein the fixed member is longer than the length of the opening in the longitudinal direction of the transparent member.

9. the transparent member is glass, the housing or the lid is made of resin, 2. The scanning optical device according to claim 1, wherein the coefficient of linear expansion of the transparent member is smaller than the coefficient of linear expansion of the housing or the cover.

10. the transparent member and the housing or the lid are made of resin, 2. The scanning optical device according to claim 1, wherein the coefficient of linear expansion of the transparent member is greater than the coefficient of linear expansion of the housing or the cover.

11. a scanning optical device according to any one of claims 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; a fixing unit for fixing the toner image transferred by the transfer unit; An image forming apparatus comprising:

Images