Optical scanner, image forming apparatus, and method for disassembling optical scanner

Abstract

To facilitate removal of a lid member from a housing accommodating a scanning optical system, while ensuring dust proof properties of an optical scanner.SOLUTION: An optical scanner comprises a scanning optical system, a housing that accommodates the scanning optical system, and a lid member. The housing has a groove part that is recessed laterally from the outside toward the inside of a side wall part and extends in a vertical direction, and a side wall engagement part that is provided in the groove part. The lid member has a drooping part that droops from an edge, and a drooping engagement part that is provided on the drooping part. When seen from the vertical direction, the groove part penetrates the side wall part in the vertical direction. In a state where the lid member is attached to the housing, the drooping part is inserted into the groove part from above to be arranged in the groove part, and the side wall engagement part and the drooping engagement part are engaged with each other in the vertical direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an optical scanning device, an image forming apparatus, and a method for disassembling an optical scanning device. [Background technology]

[0002] A conventional optical scanning device includes a scanning optical system including a mirror, a lens, etc. The scanning optical system is housed in an optical box. The optical box is composed of a housing having an opening at the top and a lid member that covers the opening of the housing. The area surrounded by the housing and the lid member is the housing area for the scanning optical system. Such an optical scanning device is disclosed, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-54803 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration in which a scanning optical system is housed in a housing area surrounded by a housing and a cover member, if the cover member is not firmly attached to the housing, dust and other particles will easily enter the housing area. In other words, the dustproofness of the optical scanning device will be reduced. However, if the cover member is firmly attached to the housing to prevent this problem, it will become difficult to remove the cover member from the housing.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide an optical scanning device, an image forming device, and a method for disassembling an optical scanning device that can easily remove a cover member from a housing that houses a scanning optical system while ensuring dustproofness of the optical scanning device. [Means for solving the problem]

[0006] To achieve the above object, an optical scanning device according to a first aspect of the present invention includes a scanning optical system that deflects and scans light emitted from a light source; a housing having a bottom and sidewalls extending upward from the bottom, the housing housing the scanning optical system in a housing area surrounded by the bottom and sidewalls; and a cover member having a top surface covering the housing area from above and an edge portion disposed on the lateral outer side of the sidewalls. The housing has a groove portion recessed inward from the lateral outer side of the sidewalls and extending in the vertical direction, and a sidewall engagement portion provided in the groove portion. The cover member has a hanging portion hanging from the edge portion and a hanging engagement portion provided in the hanging portion. The groove portion penetrates the sidewalls in the vertical direction when viewed in the vertical direction. When the cover member is attached to the housing, the hanging portion is inserted into the groove portion from above, thereby being positioned in the groove portion, and the sidewall engagement portion and the hanging engagement portion are engaged in the vertical direction.

[0007] An image forming apparatus according to a second aspect of the present invention includes the optical scanning device described above.

[0008] A method for disassembling an optical scanning device according to a third aspect of the present invention is a method for disassembling the optical scanning device described above, comprising the steps of: placing a jig below a housing to which a cover member is attached; inserting the jig into a groove portion from below the housing to bring the jig to an engagement position between the side wall engagement portion and the hanging engagement portion; and inserting the jig between the side of the groove portion and the hanging portion to elastically deform the hanging portion in a direction away from the groove portion, thereby releasing the engagement between the side wall engagement portion and the hanging engagement portion. [Effects of the Invention]

[0009] According to the present invention, the dustproofness of the optical scanning device can be ensured, and the cover member can be easily removed from the housing that houses the scanning optical system. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram of an image forming unit according to an embodiment. [Figure 3] FIG. 2 is a schematic diagram of a scanning optical system according to an embodiment. [Figure 4] FIG. 2 is a perspective view of a state in which a cover member is attached to a housing according to an embodiment. [Figure 5] 5 is a perspective view (seen from a different direction than FIG. 4) of a state in which a cover member is attached to a housing according to an embodiment. FIG. [Figure 6] FIG. 2 is a perspective view of the housing according to the embodiment with the cover member removed. [Figure 7] FIG. 2 is a perspective view of a groove and its surroundings according to an embodiment. [Figure 8] 8 is a perspective view of a groove (a groove in a small wall portion different from that in FIG. 7) and its periphery according to an embodiment. FIG. [Figure 9] 9 is a perspective view of a groove (a groove in a small wall portion different from that in FIGS. 7 and 8) and its periphery according to an embodiment. FIG. [Figure 10] FIG. 2 is a plan view of a groove and its surroundings according to the embodiment, as viewed from above. [Figure 11] 10A and 10B are diagrams illustrating a state before and after a hanging portion is inserted into a groove portion according to an embodiment. [Figure 12] FIG. 10 is a plan view of the small wall portion according to the embodiment, seen from the side. [Figure 13] 12. FIG. 14 is a plan view of a small wall portion according to an embodiment (a small wall portion different from that in FIG. 12) as viewed from the side. [Figure 14] 14 is a plan view of a small wall portion according to an embodiment (a small wall portion different from that shown in FIGS. 12 and 13) as viewed from the side. FIG. [Figure 15] 15 is a plan view of a small wall portion (different from the small wall portion in FIGS. 12 to 14) according to an embodiment, as viewed from the side. FIG. [Figure 16] 5A and 5B are schematic diagrams showing the shapes of a tip surface of a hanging portion and an upper end surface of a groove portion according to an embodiment. [Figure 17] FIG. 10 is a perspective view of a jig used in a disassembly process of the optical scanning device according to the embodiment. [Figure 18] FIG. 10 is a perspective view showing a state in which a jig is placed below a housing according to an embodiment. [Figure 19] FIG. 10 is a perspective view showing a state in which a jig is inserted into a groove according to the embodiment. [Figure 20]FIG. 10 is a perspective view showing a state in which a jig is inserted between the side of a groove portion and a hanging portion according to an embodiment. [Figure 21] 10A to 10C are diagrams illustrating a transition of states when the cover member is removed from the housing according to the embodiment. [Figure 22] 10A to 10C are diagrams illustrating a flow of a disassembly process of an optical scanning device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] An image forming apparatus equipped with an optical scanning device according to an embodiment of the present invention will be described below using a tandem color laser printer as an example. Note that the present invention is not limited to printers, but can also be applied to multifunction machines that have functions such as copying. Furthermore, the present invention is not limited to color machines, but can also be applied to monochrome machines.

[0012] <Configuration of image forming device> 1, the image forming apparatus 1000 of this embodiment is placed on a substantially flat floor surface FL. The up-down direction of the image forming apparatus 1000 is perpendicular to the floor surface FL.

[0013] The image forming apparatus 1000 includes a sheet cassette CA. The sheet cassette CA accommodates a stack of sheets S. The sheets S in the sheet cassette CA are used in a print job. The sheet cassette CA is detachable from the main body of the image forming apparatus 1000.

[0014] The image forming apparatus 1000 includes a main transport path MP, which runs from a supply position P0, through a transfer position P1 and a fixing position P2, and to an ejection tray ET.

[0015] In a print job, a sheet S in a sheet cassette CA is fed from a supply position P0 to a main transport path MP. The sheet S is transported along the main transport path MP. An image is formed using toner. The image is then printed on the sheet S while it is being transported. In other words, a transfer process of the image onto the sheet S while it is being transported is performed at a transfer position P1. A fixing process of the image onto the sheet S is performed at a fixing position P2.

[0016] The image forming apparatus 1000 includes an optical scanning device 100. The configuration of the optical scanning device 100 will be described in detail later.

[0017] The image forming apparatus 1000 also includes four image forming units 110. The four image forming units 110 correspond to the colors cyan, magenta, yellow, and black, respectively. Each of the four image forming units 110 forms an image using toner of the corresponding color. The following description focuses on one image forming unit 110, but the configuration of each of the four image forming units 110 is the same. Therefore, the description of the configuration of the other image forming units 110 will be omitted, as the following description will be used as an example.

[0018] Details of the image forming unit 110 are shown in FIG. 2. The image forming unit 110 includes a photosensitive drum 1101. The photosensitive drum 1101 is rotatably supported. The image forming unit 110 carries an image formed using toner on the outer circumferential surface of the photosensitive drum 1101. The photosensitive drum 1101 rotates with the toner image carried on its outer circumferential surface.

[0019] The image forming unit 110 includes a charging device 1102, a developing device 1103, and a cleaning device 1104. When the image forming unit 110 forms an image, the photosensitive drum 1101 rotates. The charging device 1102 charges the outer circumferential surface of the photosensitive drum 1101. The optical scanning device 100 performs scanning exposure on the outer circumferential surface of the photosensitive drum 1101. As a result, an electrostatic latent image is formed on the outer circumferential surface of the photosensitive drum 1101. In other words, the outer circumferential surface of the photosensitive drum 1101 is the scanned surface.

[0020] The developing device 1103 supplies toner to the outer peripheral surface of the photosensitive drum 1101 and develops the electrostatic latent image into a toner image. The cleaning device 1104 removes toner remaining on the outer peripheral surface of the photosensitive drum 1101 without being transferred to the intermediate transfer belt 120 (described later).

[0021] 1, the image forming apparatus 1000 also includes an intermediate transfer belt 120. The intermediate transfer belt 120 is an endless belt. The intermediate transfer belt 120 is rotatably supported. The intermediate transfer belt 120 is tensioned by a plurality of tension rollers.

[0022] One of the multiple tension rollers is connected to a belt motor (not shown). In the following description, the tension roller connected to the belt motor is referred to as a drive roller. In FIG. 1, of the multiple tension rollers, the drive roller is designated by the reference numeral 121, and the reference numerals of the other tension rollers are omitted. The intermediate transfer belt 120 rotates in response to the rotation of the drive roller 121. The other tension rollers rotate in response to the rotation of the intermediate transfer belt 120.

[0023] The image forming apparatus 1000 includes four primary transfer rollers 130. The four primary transfer rollers 130 correspond to the colors cyan, magenta, yellow, and black, respectively. Each primary transfer roller 130 is disposed on the inner circumferential side of the intermediate transfer belt 120. Each primary transfer roller 130 faces a photosensitive drum 1101 carrying an image of the corresponding color, via the intermediate transfer belt 120. Each primary transfer roller 130 is in pressure contact with the photosensitive drum 1101 carrying an image of the corresponding color, via the intermediate transfer belt 120.

[0024] The image forming apparatus 1000 includes a secondary transfer roller 140. The secondary transfer roller 140 is in pressure contact with the outer circumferential surface of the intermediate transfer belt 120 at a transfer position P1. The secondary transfer roller 140 sandwiches the intermediate transfer belt 120 between itself and a drive roller 121, forming a transfer nip between itself and the outer circumferential surface of the intermediate transfer belt 120. This forms the transfer nip at the transfer position P1. The main transport path MP passes through the transfer nip.

[0025] In a print job, the sheet S is transported toward the transfer position P1 (that is, the transfer nip). The sheet S passes through the transfer nip during transport.

[0026] Each image forming unit 110 forms an image using toner of a corresponding color. Each primary transfer roller 130 primarily transfers the image onto the outer circumferential surface of the intermediate transfer belt 120.

[0027] The intermediate transfer belt 120 rotates while carrying on its outer circumferential surface an image that is primarily transferred from each photosensitive drum 1101. While the sheet S is passing through the transfer nip, the sheet S comes into contact with the outer circumferential surface of the intermediate transfer belt 120. The secondary transfer roller 140 performs a second transfer of the image onto the sheet S that is passing through the transfer nip.

[0028] The image forming apparatus 1000 includes a fixing unit 150. The fixing unit 150 includes a heating roller and a pressure roller. The fixing unit 150 is disposed at a fixing position P2. The heating roller has a built-in heater. The pressure roller is in pressure contact with the heating roller. The heating roller and the pressure roller are in pressure contact with each other to form a fixing nip at the fixing position P2.

[0029] In a print job, the sheet S passes through the fixing position P2. That is, the sheet S is sandwiched in the fixing nip. The fixing unit 150 heats the sheet S as it passes through the fixing position P2. At the fixing position P2, pressure is applied to the sheet S. The fixing unit 150 applies heat and pressure to the sheet S to fix the toner image to the sheet S. The sheet S that has undergone the fixing process is discharged to an output tray ET.

[0030] The image forming apparatus 1000 can execute a single-sided print job in which an image is printed on only one side of a sheet S, as well as a double-sided print job in which an image is printed on both sides of a sheet S. To execute a double-sided print job, the image forming apparatus 1000 is provided with a double-sided printing transport path DP.

[0031] The double-sided printing transport path DP branches off from the main transport path MP at a branching position P3 downstream of the fixing position P2 in the sheet transport direction, and merges with the main transport path MP at a merging position P4 upstream of the transfer position P1 in the sheet transport direction.

[0032] If the job to be executed is a single-sided print job, the sheet S passes through the transfer nip only once, and a single transfer process is performed on the sheet S while it is passing through the transfer nip. After the first transfer process, the sheet S is discharged directly onto the discharge tray ET.

[0033] If the job being executed is a double-sided printing job, the sheet S passes through the transfer nip twice, with one transfer process performed on each of the front and back sides of the sheet S. Specifically, the first time the sheet S passes through the transfer nip, the transfer process is performed on one side of the sheet S. After the first transfer process, the sheet S is switched back after the rear edge of the sheet S passes through branch position P3 but before the sheet S is completely discharged onto the discharge tray ET. This causes the rear edge of the sheet S to be drawn into the double-sided printing conveyance path DP.

[0034] Thereafter, the sheet S is transported along the double-sided printing transport path DP. Then, the sheet S on the double-sided printing transport path DP is returned to the main transport path MP from the junction position P4. The sheet S returned to the main transport path MP is transported along the main transport path MP and passes through the transfer nip again. At this time, the orientation of the front and back surfaces of the sheet S is reversed to the orientation when it passed through the transfer nip the previous time. As a result, when the sheet S passes through the transfer nip for the second time, the transfer process is performed on the other side of the sheet S that is opposite to the one side.

[0035] <Configuration of optical scanning device> 3, the optical scanning device 100 includes a scanning optical system 1. The scanning optical system 1 includes a light source 10. The scanning optical system 1 forms an electrostatic latent image on the outer peripheral surface of a photosensitive drum 1101 by deflecting and scanning light emitted from the light source 10.

[0036] The light source 10 has a plurality of semiconductor lasers corresponding to the colors cyan, magenta, yellow, and black, respectively. Each semiconductor laser emits laser light for forming an electrostatic latent image that forms the basis of an image of the corresponding color.

[0037] The scanning optical system 1 includes a polygon mirror 11. The polygon mirror 11 is a rotating polygonal mirror having a plurality of light-reflecting surfaces. The polygon mirror 11 is rotated by a driving force transmitted from a polygon motor 11a. While the polygon mirror 11 is rotating, light emitted from the light source 10 is incident on the reflecting surface of the polygon mirror 11. As the polygon mirror 11 rotates, it deflects and scans the light incident on its reflecting surface.

[0038] The scanning optical system 1 includes a light reflecting mirror 12 and a scanning lens 13. An fθ lens is used as the scanning lens 13. Alternatively, a collimator lens, a cylindrical lens, or the like may be installed as the scanning lens 13. The polygon mirror 11, the light reflecting mirror 12, and the scanning lens 13 guide the light emitted from the light source 10 to the outer peripheral surface of the photosensitive drum 1101.

[0039] The optical scanning device 100 includes a housing 2 and a cover member 3. The housing 2 and the cover member 3 are both made of resin. The housing 2 is box-shaped with an opening at the top. The cover member 3 is placed in the opening at the top of the housing 2. In other words, the cover member 3 covers the opening of the housing 2 from above. The scanning optical system 1 is housed in an area 100A surrounded by the housing 2 and the cover member 3. In the following description, the area 100A will be referred to as the housing area 100A.

[0040] <Configurations of the housing and the cover member> 4 to 16, the configurations of the housing 2 and the cover member 3 will be described below. In the drawings, the up-down direction of the optical scanning device 100 is indicated by an arrow D. In the up-down direction, the direction indicated by the symbol Du is the upward direction, and the direction indicated by the symbol Dd is the downward direction.

[0041] In the following description, the direction perpendicular to the up-down direction will be referred to as the side. In the drawings, the side is indicated by the arrow Ds. Furthermore, in the following description, the side toward the center of the storage area 100A will be referred to as the inside side, and the side away from the center of the storage area 100A will be referred to as the outside side. In the drawings, the inside side will be referred to as "In" and the outside side will be referred to as "Out."

[0042] As shown in Figures 4 to 6, the housing 2 has a bottom 21. The bottom 21 covers the storage area 100A from below. In other words, the area above the bottom 21 is the storage area 100A. The bottom 21 has a substantially rectangular outer shape when viewed from the top-bottom direction.

[0043] The housing 2 has a side wall 22. The side wall 22 extends upward from the bottom 21. The side wall 22 surrounds the storage area 100A from the sides. That is, the housing 2 has an area surrounded by the bottom 21 and the side wall 22 as the storage area 100A.

[0044] The side wall 22 is composed of four small walls 22A, 22B, 22C, and 22D. The small walls 22A and 22C face each other in one lateral direction with the storage area 100A in between, and the small walls 22B and 22D face each other in the other lateral direction (a direction perpendicular to the one lateral direction) with the storage area 100A in between. In other words, the four small walls 22A to 22D are arranged to surround the storage area 100A in a substantially rectangular shape when viewed from above and below.

[0045] The cover member 3 has a top surface 31. The top surface 31 covers the accommodation area 100A from above. In other words, the cover member 3 covers the scanning optical system 1 from above. The top surface 31 has an exit opening (reference numeral omitted) in which glass is fitted. Light is emitted through this exit opening.

[0046] The cover member 3 has an edge 32. When viewed from the top-bottom direction, the edge 32 corresponds to the peripheral edge of the top surface 31. When viewed from the top-bottom direction, the edge 32 has a frame-like shape that surrounds the top surface 31. When the cover member 3 is attached to the housing 2, the edge 32 is located on the outer lateral side of the upper end of the side wall 22. In other words, when the cover member 3 is attached to the housing 2, the upper end of the side wall 22 is fitted into the inner lateral side of the edge 32.

[0047] In this embodiment, the housing 2 has grooves 221. The grooves 221 are provided in the side wall 22 and are recessed from the outer lateral side toward the inner lateral side of the side wall 22. One of the grooves 221 provided in the small wall 22A is shown in FIG. 7, one of the grooves 221 provided in the small wall 22B is shown in FIG. 8, and one of the grooves 221 provided in the small wall 22C is shown in FIG. 9.

[0048] The groove 221 extends linearly in the vertical direction. Specifically, the groove 221 penetrates the side wall 22 in the vertical direction when viewed from the vertical direction. The groove 221 extends in the vertical direction on the outer lateral side of the side wall 22, opens upward at the upper end of the side wall 22, and opens downward at the lower end of the side wall 22. The groove 221 extends without being blocked in the vertical direction. A plan view of the groove 221 and its surroundings viewed from above is shown in FIG. 10.

[0049] The housing 2 also has a sidewall engaging portion 222. The sidewall engaging portion 222 is provided in the groove portion 221. Specifically, the sidewall engaging portion 222 is provided on a surface of the groove portion 221 facing laterally outward (here, this surface is referred to as the groove bottom surface). The sidewall engaging portion 222 is a protrusion that protrudes laterally outward from the groove bottom surface of the groove portion 221. In the following description, the sidewall engaging portion 222 is referred to as the engaging protrusion 222. Furthermore, a portion including the groove portion 221 and the engaging protrusion 222 is referred to as the housing mounting portion 220.

[0050] 11, the cover member 3 has a hanging portion 321. The hanging portion 321 is provided on the edge portion 32. The hanging portion 321 has a shape that hangs down from the edge portion 32. In other words, the hanging portion 321 protrudes downward from the edge portion 32.

[0051] Furthermore, lid member 3 has a hanging engagement portion 322 that can engage with side wall engagement portion 222. Hanging engagement portion 322 is provided on hanging portion 321. Hanging engagement portion 322 is a through hole that penetrates hanging portion 321 from the lateral outer side to the lateral inner side. In the following description, hanging engagement portion 322 will be referred to as engagement hole 322. Furthermore, the portion including hanging portion 321 and engagement hole 322 will be referred to as lid mounting portion 320.

[0052] In this embodiment, there are a plurality of housing mounting portions 220 (i.e., grooves 221 and engaging protrusions 222) and a plurality of lid mounting portions 320 (i.e., hanging portions 321 and engaging holes 322). Specifically, a housing mounting portion 220 is provided on each of all of small wall portions 22A to 22D of side wall portion 22 of housing 2, and the same number of lid mounting portions 320 as the housing mounting portions 220 are provided on edge portion 32 of lid member 3.

[0053] Three housing mounting portions 220 are provided on small wall portion 22A (see FIG. 12). Three housing mounting portions 220 are provided on small wall portion 22B (see FIG. 13). Two housing mounting portions 220 are provided on small wall portion 22C (see FIG. 14). One housing mounting portion 220 is provided on small wall portion 22D (see FIG. 15). Each of FIGS. 12 to 15 is a plan view of side wall portion 22 as viewed from the outside and to the side.

[0054] 12 to 15 are merely examples. At least one housing mounting portion 220 may be provided on each of at least three small wall portions among the small wall portions 22A to 22D. For example, the cover member 3 may be attached to one of the small wall portions 22A to 22D by another method.

[0055] When cover member 3 is attached to housing 2, each of multiple engagement protrusions 222 engages with a different engagement hole 322. Specifically, as shown in Fig. 11 , hanging portion 321 is inserted into groove portion 221 from above, thereby placing hanging portion 321 in groove portion 221. Engagement protrusions 222 then engage with the inner edges of engagement holes 322 in the vertical direction. In Fig. 11 , the upper diagram shows the state before cover member 3 is attached to housing 2, and the lower diagram shows the state after cover member 3 is attached to housing 2. Hanging portion 321 is inserted into groove portion 221 in the direction shown by the dashed-dotted arrow in Fig. 11 .

[0056] This prevents the lid member 3 from coming off upward from the housing 2. Furthermore, by providing housing attachment portions 220 on three or more of the small wall portions 22A to 22D and attaching the lid member 3 to the housing 2 using these housing attachment portions 220, the attachment of the lid member 3 to the housing 2 becomes stronger. When the attachment of the lid member 3 to the housing 2 becomes stronger, it is possible to prevent dust and other particles from entering the accommodation area 100A. In other words, the dustproofness of the optical scanning device 100 is improved.

[0057] <Assembly of optical scanning device> In the assembly process of the optical scanning device 100, first, the scanning optical system 1 is accommodated in the accommodation area 100A of the housing 2. Then, the cover member 3 is placed in a position to cover the accommodation area 100A from above, and the cover member 3 is attached to the housing 2.

[0058] When lid member 3 is attached to housing 2, hanging portion 321 is inserted into groove portion 221 from above. In this state, lid member 3 is pressed down onto housing 2. As a result, the tip of hanging portion 321 comes into contact with engaging protrusion 222 from above. Thereafter, lid member 3 is pressed down further with the tip of hanging portion 321 still in contact with engaging protrusion 222 from above.

[0059] At this time, hanging portion 321 elastically deforms laterally and outward, and when engagement hole 322 reaches the installation position of engagement protrusion 222, engagement protrusion 222 is inserted into engagement hole 322, causing hanging portion 321 to return from the elastically deformed state to its original state (i.e., a non-elastically deformed state). As a result, engagement protrusion 222 and engagement hole 322 engage in the vertical direction. In other words, cover member 3 is attached to housing 2.

[0060] 16, in this embodiment, hanging portion 321 has a tip end surface 321a that faces laterally inward and is inclined laterally outward as it extends downward. Groove portion upper end surface 221a that faces laterally outward and is inclined upward and laterally inward as it extends upward. In addition, angle of inclination θ1 of hanging portion tip surface 321a with respect to a direction perpendicular to the up-down direction is greater than angle of inclination θ2 of groove portion upper end surface 221a with respect to a direction perpendicular to the up-down direction.

[0061] In other words, tilt angle θ1 is the angle between leading end surface 321a of hanging portion and the direction perpendicular to the up-down direction. In addition, tilt angle θ2 is the angle between upper end surface 221a of groove portion and the direction perpendicular to the up-down direction. Since tilt angle θ1 is greater than tilt angle θ2, the leading end of hanging portion 321 is sharper than the upper end of groove portion 221.

[0062] With this configuration, when hanging portion 321 is inserted into groove portion 221 from above (see FIG. 16), the tip of hanging portion 321 is less likely to get caught on the upper end of groove portion 221. This allows hanging portion 321 to be smoothly inserted into groove portion 221 from above. In FIG. 16, the insertion direction of hanging portion 321 into groove portion 221 is indicated by a dashed-dotted arrow. Note that a similar effect can be obtained even if only one of hanging portion tip surface 321a and groove upper end surface 221a is inclined.

[0063] <Disassembly of optical scanning device> In other words, the disassembly process of the optical scanning device 100 is a process of removing the cover member 3 from the housing 2. In the disassembly process of the optical scanning device 100, a jig 4 as shown in FIG.

[0064] The jig 4 has a base portion 40. The jig 4 also has detachable portions 41 extending upward from the base portion 40. The detachable portions 41 have sharpened tips. The number of detachable portions 41 is the same as the number of casing attachment portions 220 (i.e., the number of groove portions 221). The jig 4 has a plurality of detachable portions 41 assigned to the plurality of casing attachment portions 220, respectively.

[0065] Then, in the process of disassembling the optical scanning device 100 (i.e., the process of removing the cover member 3 from the housing 2), first, the jig 4 is placed below the housing 2 to which the cover member 3 is attached (see FIG. 18). At this time, the lateral positions of the groove 221 and the detachment part 41 are aligned. In this state, the housing 2 is moved downward toward the jig 4. As a result, the jig 4 is inserted into the groove 221. Specifically, the tip of the detachment part 41 is inserted into the groove 221 (see FIG. 19).

[0066] Next, with jig 4 inserted in groove 221, housing 2 is pushed down, and jig 4 is inserted between the side of groove 221 and hanging portion 321. Specifically, the tip of detachment portion 41 is inserted between the side of groove 221 and hanging portion 321 (see FIG. 20). This changes the state from that shown in the upper diagram of FIG. 21 to that shown in the middle diagram of FIG.

[0067] By inserting jig 4 between the sides of groove portion 221 and hanging portion 321, hanging portion 321 elastically deforms laterally and outward. In other words, hanging portion 321 elastically deforms in a direction away from groove portion 221. That is, the state shown in the middle diagram of FIG. 21 changes to the state shown in the bottom diagram of FIG. 21. This releases the engagement between engagement protrusion 222 and engagement hole 322. As a result, cover member 3 can be removed from housing 2.

[0068] 22, the disassembly process for optical scanning device 100 includes preparation process #1, jig insertion process #2, and disengagement process #3. Preparation process #1 is a process of placing jig 4 below housing 2 to which cover member 3 is attached. Jig insertion process #2 is a process of inserting jig 4 into groove portion 221 from below housing 2 and bringing jig 4 to engagement position EP (see FIG. 18) between engagement protrusion 222 and engagement hole 322. Disengagement process #3 is a process of inserting jig 4 between the side of groove portion 221 and hanging portion 321 and elastically deforming hanging portion 321 in a direction away from groove 221, thereby disengaging engagement protrusion 222 from engagement hole 322.

[0069] In this embodiment, by providing an engaging protrusion 222 in a groove 221 that penetrates the side wall 22 in the vertical direction, the lid member 3 can be removed from the housing 2 using the jig 4. This makes it possible to easily remove the lid member 3 from the housing 2, even if the lid member 3 is firmly attached to the housing 2 by attaching it to the housing 2 using multiple housing attachment portions 220. In other words, the lid member 3 can be easily removed from the housing 2 while ensuring the dustproofness of the optical scanning device 100.

[0070] Here, in this embodiment, a jig 4 having multiple removal portions 41 is used. For this reason, in jig insertion process #2, the jig 4 (i.e., removal portions 41) are inserted into multiple engagement positions EP simultaneously. Then, in disengagement process #3, the engagement between the engagement protrusions 222 and the engagement holes 322 at the multiple engagement positions EP is released simultaneously. As a result, even if the cover member 3 is attached to the housing 2 at multiple locations (i.e., the engagement between the engagement protrusions 222 and the engagement holes 322), the attachment at these multiple locations can be released simultaneously.

[0071] 7 to 9, in this embodiment, groove lower end surface 221b, which faces the lateral outer side of the lower end of groove 221, is inclined downward and laterally inward. This makes it possible to prevent jig 4 (specifically, the tip of removal portion 41) from getting caught on the lower end of groove 221 when inserting jig 4 (specifically, the tip of removal portion 41) into groove 221 from below casing 2. In other words, jig 4 can be inserted into groove 221 smoothly.

[0072] 7 and 9, the side wall 22 has a recess 20 recessed laterally and inward in the middle portion from the upper end to the lower end. The groove 221 extends from the upper end of the side wall 22 across the recess 20 to the lower end of the side wall 22.

[0073] Therefore, in this embodiment, the upper portion 20a of the inner edge of the recess 20 is inclined downward and laterally inward. In other words, the upper portion 20a of the inner edge of the recess 20 is chamfered. This makes it possible to prevent the jig 4 from getting caught on the inner edge of the recess 20 when the housing 2 is pressed down with the jig 4 inserted in the groove 221.

[0074] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0075] 1. Scanning optical system 2. Case 3 Cover member 4 Jig 10 light source 20 recess 20a Upper part 21 Bottom 22 Side wall 22A, 22B, 22C, 22D Small wall section 31 Top section 32 Edge 100 Optical scanning device 100A Containment Area 221 ditch 221a Groove upper end surface 221b Groove lower end surface 222 Fastening protrusion (side wall fastening part) 321 hanging part 321a Tip of the hanging part 322 fastening hole (hanging fastening part) 1000 image forming device EP engagement position

Claims

1. a scanning optical system that deflects and scans light emitted from a light source; a housing having a bottom and a sidewall extending upward from the bottom, the housing housing the scanning optical system in a housing area surrounded by the bottom and the sidewall; a cover member having a top surface portion that covers the storage area from above and an edge portion that is disposed laterally outside the side wall portion, The housing includes: a groove portion recessed from a lateral outer side toward an inner side of the side wall portion and extending in the vertical direction; a sidewall engaging portion provided in the groove portion, The cover member is a hanging portion hanging from the edge portion; a hanging engagement portion provided on the hanging portion, The groove portion penetrates the side wall portion in the up-down direction when viewed from the up-down direction, When the cover member is attached to the housing, the hanging portion is inserted into the groove portion from above and positioned in the groove portion, and the side wall engagement portion and the hanging engagement portion are engaged in the vertical direction.

2. the sidewall engaging portion is a protrusion that protrudes laterally outward from the groove portion, the hanging engagement portion is a through hole that penetrates the hanging portion from a lateral outer side toward an inner side, 2. The optical scanning device according to claim 1, wherein the projection is engaged with an inner edge of the engagement hole in the vertical direction when the cover member is attached to the housing.

3. The side wall portion is composed of four small wall portions arranged so as to surround the storage area in a rectangular shape when viewed from above and below, The side wall engaging portions are plural and are provided on at least three of the small wall portions, respectively; The optical scanning device according to claim 1 , wherein the number of the hanging engagement portions is the same as the number of the side wall engagement portions, and the hanging engagement portions are engaged with the plurality of side wall engagement portions, respectively.

4. The optical scanning device according to claim 1 , wherein a tip surface of the hanging portion facing laterally inward of a tip of the hanging portion is inclined downward and laterally outward.

5. The optical scanning device according to claim 1 , wherein an upper end surface of the groove facing laterally outward is inclined laterally inward as it extends upward.

6. a tip surface of the hanging portion facing laterally inward of a tip of the hanging portion is inclined downward and laterally outward, an upper end surface of the groove portion facing laterally outward of the upper end portion of the groove portion is inclined laterally inward as it extends upward; 2. The optical scanning device according to claim 1, wherein an inclination angle of the tip end surface of the hanging portion relative to a direction perpendicular to the vertical direction is larger than an inclination angle of the upper end surface of the groove relative to a direction perpendicular to the vertical direction.

7. The optical scanning device according to claim 1 , wherein a lower end surface of the groove facing laterally outward is inclined downwardly and laterally inwardly.

8. The side wall portion has a recessed portion recessed laterally and inwardly in an intermediate portion from the upper end to the lower end, the groove extends from an upper end of the side wall portion across the recess to a lower end of the side wall portion, The optical scanning device according to claim 1 , wherein an upper portion of an edge of the recess is inclined laterally and inwardly downward.

9. An image forming apparatus comprising the optical scanning device according to any one of claims 1 to 8.

10. A method for disassembling the optical scanning device according to any one of claims 1 to 8, comprising: placing a jig below the housing to which the lid member is attached; a step of inserting the jig into the groove from below the housing to bring the jig to an engagement position between the side wall engagement portion and the hanging engagement portion; a step of inserting the jig between the sides of the groove portion and the hanging portion to elastically deform the hanging portion in a direction away from the groove portion, thereby releasing the engagement between the side wall engagement portion and the hanging engagement portion.

11. The engagement positions are plural, The method for disassembling an optical scanning device according to claim 10 , wherein the jig is inserted into a plurality of the engagement positions simultaneously, thereby simultaneously releasing the engagement between the side wall engagement portion and the hanging engagement portion at the plurality of engagement positions.

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