Light guide device, drum unit, image forming apparatus, and image reading apparatus

Abstract

To provide a light guide device that can improve the accuracy of positioning of a light emitting element on a light source substrate and a light guide body, and can improve the accuracy of assembly of members including the light source substrate and the light guide body, a drum unit, an image forming apparatus, and an image reading device.SOLUTION: A drum unit 18 of an image forming apparatus 10 comprises a housing 19, a light guide member 72, a cover member 62, and a pressing member 85. The light guide member 72 is provided with projections 76 for positioning. The cover member 62 has an engagement hook 625 that is engaged with an engaging piece 203 on a support frame 61 of the housing 19 in a state in which the pressing member 85 is caused to exert an urging force in a pressing direction D31.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a light guide device including a light guide member that guides light from a light source.

Background Art

[0002] In an electrophotographic image forming apparatus, a laser beam is irradiated onto the surface of a uniformly charged photosensitive drum, thereby forming an electrostatic latent image on the surface of the photosensitive drum. The electrostatic latent image on the photosensitive drum is developed by a developing device using toner (developer). After the toner image on the photosensitive drum is transferred to a transfer member such as a sheet or an intermediate transfer belt, a charge-removing light beam is irradiated onto the surface of the photosensitive drum. Thereby, the residual charge on the surface of the photosensitive drum is removed. After removing the residual charge, the surface of the photosensitive drum is cleaned by a cleaning unit.

[0003] As a device for irradiating the charge-removing light beam, a configuration including a light source substrate having a light-emitting element and a light guide member that guides the light emitted from the light-emitting element to the photosensitive drum is known.

[0004] Conventionally, in an exposure apparatus having a substrate having a light-emitting element and an optical system that converges the light from the light-emitting element, a configuration in which the substrate is pressed by a pressing member to regulate the position of the substrate is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, in order to stabilize the intensity of the static elimination light irradiated onto the surface of the photoreceptor drum, the positioning accuracy of the light-emitting element and the light-guiding member is important. If the positioning accuracy is low, variations will occur in the intensity of the static elimination light. Furthermore, even if the positional relationship between the light-emitting element and the light-guiding member is appropriate, if the assembly accuracy of the light source substrate, the light-guiding member, and the support members that support them is low, variations may occur in the intensity of the static elimination light. In addition, in a method of stacking and assembling multiple members such as the light source substrate, the light-guiding member, or other members on the support member (see Patent Document 1), the assembly tolerances of each member accumulate, and the assembly accuracy may decrease due to these accumulated tolerances.

[0007] The object of the present invention is to provide a light guide device, drum unit, image forming apparatus, and image reading apparatus that can improve the positioning accuracy of the light guide member with respect to the support member, and also improve the assembly accuracy of each component such as the light guide member and the light source substrate. [Means for solving the problem]

[0008] A light guide device according to one aspect of the present invention comprises a support member, a light guide member, a first contact portion, and a cover member. The light guide member is supported by the support member and has a light incident surface into which light is incident. The first contact portion is provided on the light guide member and positions the light guide member at a predetermined first reference position on the support member by contacting a contacted portion of the support member. The cover member is attached to the support member and covers the light guide member. When attached to the support member, the cover member has a first biasing portion that biases the light guide member in the contact direction in which the first contact portion contacts the contacted portion, and an engaging portion that engages with the engaged portion of the support member while the first biasing portion is generating a biasing force in the contact direction.

[0009] A drum unit according to another aspect of the present invention is used when mounted on an image forming apparatus. The drum unit comprises a support member, a light guide member, a first contact portion, and a cover member. The support member rotatably supports a photoreceptor drum. The light guide member is supported by the support member and has a light incident surface into which light is incident, and deflects the light incident on the light incident surface to irradiate the photoreceptor drum with light. The first contact portion is provided on the light guide member and positions the light guide member at a predetermined first reference position on the support member by contacting a portion of the support member to which the support member is to be contacted. The cover member is attached to the support member and covers the light guide member. When attached to the support member, the cover member has a first biasing portion that biases the light guide member in the contact direction in which the first contact portion contacts the portion to be contacted, and an engaging portion that engages with the engaged portion of the support member while the first biasing portion is generating a biasing force in the contact direction.

[0010] An image forming apparatus according to another aspect of the present invention comprises the drum unit and develops the electrostatic latent image formed on the surface of the photoreceptor drum with a developer.

[0011] An image forming apparatus according to another aspect of the present invention comprises the light guide device and a photosensitive drum that is irradiated with light by the light guide device.

[0012] An image reading device according to another aspect of the present invention comprises a light guide device and an irradiated object to which light guided by the light guide device is irradiated, and reads an image of the irradiated surface of the irradiated object based on the reflected light from the irradiated object. [Effects of the Invention]

[0013] According to the present invention, it is possible to improve the positioning accuracy of the light guide member with respect to the support member, as well as to improve the assembly accuracy of each component, such as the light guide member and the light source substrate. [Brief explanation of the drawing]

[0014] [Figure 1]FIG. 1 is a diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of an image forming unit of the image forming apparatus. [Figure 3] FIG. 3 is a perspective view of a drum unit of the image forming unit. [Figure 4] FIG. 4 is a partially enlarged view showing the configuration of the right end portion of the drum unit. [Figure 5] FIG. 5 is a partially enlarged view showing the configuration of the left end portion of the drum unit. [Figure 6] FIG. 15 is an exploded perspective view of the drum unit, showing a state in which a cover member is removed from the housing of the drum unit. [Figure 7] FIG. 18 is a partially enlarged view schematically showing the attachment mechanism of the cover member. [Figure 8] FIG. 21 is an exploded perspective view of the drum unit, showing a state in which a light guide member is removed from the housing of the drum unit. [Figure 9] FIG. 24 is a cross-sectional view when the drum unit is cut along a vertical plane behind the light guide member. [Figure 10] FIG. 27 is an enlarged cross-sectional view of the main part XIII in FIG. 9, showing the configuration around the right end portion of the light guide member and the light source substrate. [Figure 11] FIG. 30 is a diagram showing the internal configuration of the right end portion of the drum unit. [Figure 12] FIG. 33 is a perspective view showing the side cover on the right side of the drum unit and the configuration inside thereof. [Figure 13] FIG. 36 is an enlarged cross-sectional view of the main part XIII in FIG. 9, showing the configuration around the right end portion of the light guide member and the light source substrate.

MODE FOR CARRYING OUT THE INVENTION

[0015] It should be noted that in the original text, there is a misrepresentation in item . It is assumed that the correct text should be "図15は、ドラムユニットの分解斜視図であり、ドラムユニットのハウジングからカバー部材が取り外された状態を示す。" instead of "図6は、ドラムユニットの分解斜視図であり、ドラムユニットのハウジングからカバー部材が取り外された状態を示す。" So the translation is adjusted accordingly. If this is not what you intended, please correct the original text for a more accurate translation.Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. The embodiments described below are merely examples embodying the present invention and do not limit the technical scope of the present invention. In the following description, the vertical direction D1, the front-back direction D2, and the left-right direction D3 defined based on the installation state (the state shown in FIG. 1) in which the image forming apparatus 10 can be used may be used.

[0016] FIG. 1 is a diagram showing the configuration of an image forming apparatus 10 according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 10 includes a plurality of image forming units 1 to 4, an intermediate transfer belt 5, an optical scanning device 6, a secondary transfer roller 7, a fixing device 8, a paper discharge tray 9, toner containers 21 to 24, a paper feed cassette 31, a conveyance path 32, and a housing 33 that houses these components. The image forming apparatus 10 is, for example, a color printer. The image forming apparatus 10 forms a color image or a monochrome image based on image data input from an information processing device such as a personal computer on a sheet (an example of a recording medium) such as paper supplied from the paper feed cassette 31 along the conveyance path 32. Note that the image forming apparatus 10 may be any apparatus having a printing function, and may be, for example, a copying machine, a FAX apparatus, or the like.

[0017] The image forming units 1 to 4 are arranged side by side along the running direction D10 of the intermediate transfer belt 5. The image forming units 1 to 4 constitute a so-called tandem type image forming unit. The image forming unit 1 forms a toner image corresponding to yellow, the image forming unit 2 forms a toner image corresponding to magenta, the image forming unit 3 forms a toner image corresponding to cyan, and the image forming unit 4 forms a toner image corresponding to black.

[0018] Figure 2 is a schematic diagram showing the configuration of the image forming unit 1. As shown in Figure 2, the image forming unit 1 comprises a drum unit 18, a developing device 13, and a primary transfer roller 15. The drum unit 18 also comprises a photoreceptor drum 11, a charging unit 12, a static elimination unit 14 (an example of a light guide device of the present invention), and a cleaning unit 16. The image forming unit 1 forms a toner image on the photoreceptor drum 11 according to the electrophotographic method and transfers the toner image to the intermediate transfer belt 5. Note that the image forming units 2 to 4 have the same configuration as the image forming unit 1, so their explanation is omitted here.

[0019] The drum unit 18 is detachably mounted to the image forming apparatus 10. In this embodiment, the drum unit 18 is mounted to the housing 33 by being inserted from the right side of the image forming apparatus 10 to the rear (left) side of the housing 33. The drum unit 18 has a housing 19 that accommodates a photoreceptor drum 11, a charging unit 12, a static elimination unit 14, and a cleaning unit 16. The photoreceptor drum 11 is rotatably supported in the housing 19. The drum unit 18 also further includes a positioning mechanism 80 (see Figure 13).

[0020] The photoreceptor drum 11 is located below the intermediate transfer belt 5. The photoreceptor drum 11 is an image carrier that holds an electrostatic latent image and a toner image. The charging unit 12 is located inside the housing 19 and is positioned below the photoreceptor drum 11. The charging unit 12 has a charging roller 121 that charges the photoreceptor drum 11 with power supplied from a power supply (not shown). The surface of the photoreceptor drum 11 is uniformly charged by the charging unit 12. Laser light is irradiated onto the surface of the photoreceptor drum 11 by the optical scanning device 6. As a result, an electrostatic latent image based on image data is formed on the surface of the photoreceptor drum 11. The developing device 13 has a developing roller 131 that develops the electrostatic latent image formed on the photoreceptor drum 11 with toner (an example of a developer). The developing device 13 is supplied with toner from toner containers 21-24 of the corresponding color.

[0021] The primary transfer roller 15 transfers the toner image formed on the photoreceptor drum 11 to the intermediate transfer belt 5. The intermediate transfer belt 5 is an intermediate transfer member that travels above the photoreceptor drum 11 of each of the image forming units 1 to 4, and sequentially transfers the toner images of each color formed on each photoreceptor drum 11. The toner image transferred to the intermediate transfer belt 5 is then transferred to a sheet being transported along the transport path 32 by the secondary transfer roller 7 (see Figure 1). After that, the toner image transferred to the sheet is heated by the fixing device 8 and fixed to the sheet.

[0022] The cleaning unit 16 has a cleaning roller 161 that cleans the photoreceptor drum 11 after the toner image has been transferred. After the static elimination unit 14 removes residual charge from the surface of the photoreceptor drum 11, the cleaning roller 161 removes any remaining toner from the surface of the photoreceptor drum 11.

[0023] The static elimination unit 14 irradiates the region P1 on the outer surface of the photoreceptor drum 11 between the primary transfer roller 15 and the cleaning roller 161 with static elimination light L1 to eliminate static charge from the photoreceptor drum 11. In other words, the static elimination unit 14 irradiates the region P1 on the surface of the photoreceptor drum 11 that is downstream of the primary transfer roller 15 in the rotational direction D11 and upstream of the cleaning roller 161 with static elimination light L1. This removes residual charge in region P1. As a result, the removal of residual toner becomes easier, and so-called memory images on the photoreceptor drum 11 are suppressed.

[0024] Figure 3 is a perspective view of the drum unit 18. The drum unit 18 rotatably supports the photoreceptor drum 11 and, as shown in Figure 3, is formed in an elongated shape in the left-right direction D3. The drum unit 18 is attached to the internal frame of the housing 33, etc., with its longitudinal direction coinciding with the left-right direction D3.

[0025] As shown in Figure 3, the housing 19 of the drum unit 18 has a housing body 20 (an example of a support member of the present invention) that is elongated in the left-right direction, a pair of side plates 201 and 202, and a side cover 63 (an example of a side member of the present invention).

[0026] A pair of side plates 201 and 202 are provided at each of the longitudinal ends of the housing body 20. The pair of side plates 201 and 202 are integrally formed with the housing body 20. As shown in Figure 4, side plate 201 is provided on the right side of the housing body 20. Also, as shown in Figure 5, side plate 202 is provided on the left side of the housing body 20. Both ends of the photoreceptor drum 11 are rotatably supported by the pair of side plates 201 and 202.

[0027] The side cover 63 is provided at one end of the housing body 20 in the longitudinal direction. As shown in Figure 4, the side cover 63 is attached to the outer (right) side of the side plate 201 of the housing body 20. The side cover 63 is attached so as to cover the side of the side plate 201.

[0028] Furthermore, the charging roller 121 and the cleaning roller 161 (see Figure 2) are also rotatably supported by the housing 19. In this embodiment, the drum unit 18 is unitized by attaching the photoreceptor drum 11, the charging section 12, the cleaning section 16, etc., to the housing 19.

[0029] As shown in Figure 2, the static elimination unit 14 is provided in the housing 19 of the drum unit 18. As described above, the static elimination unit 14 irradiates the surface of the photoreceptor drum 11 with static elimination light L1, and is an example of the light guide device of the present invention. In this embodiment, the static elimination unit 14 is provided integrally with the drum unit 18.

[0030] Figure 6 is an exploded perspective view of the drum unit 18, showing the drum unit 18 with the cover member 62 removed from the housing 19. Figure 7 is a schematic enlarged view of the mounting mechanism of the cover member 62. Figure 8 is an exploded perspective view of the drum unit 18, showing the drum unit 18 with the light guide member 72 removed from the housing 19. Note that the side cover 63 is not shown in Figures 6 and 8.

[0031] As shown in Figure 6, the static elimination unit 14 comprises a support frame 61, a light guide member 72 (an example of a light guide member of the present invention), a cover member 62 (an example of a cover member of the present invention), a light source substrate 71 (an example of a light source substrate of the present invention), and a pressing member 85 (an example of a first biasing member of the present invention).

[0032] The support frame 61 supports the light guide member 72 and is integrally formed with the housing body 20. The support frame 61 constitutes the upper part of the housing body 20. The support frame 61 is located on the rear side of the photoreceptor drum 11 and is provided to span the side plates 201 and 202 of the housing body 20. Note that the support frame 61 does not have to be integrally formed with the housing body 20; it may be constructed independently of the housing body 20 and attached to the upper part of the housing body 20.

[0033] The light guide member 72 is supported by a support frame 61 at the top of the housing body 20. In detail, the light guide member 72 is formed in an elongated shape in the longitudinal direction (left-right direction D3) of the drum unit 18. The light guide member 72 is formed in a rod shape, for example, from transparent acrylic resin. The light guide member 72 is formed to be longer than the photoreceptor drum 11, and is positioned so that its longitudinal direction is parallel to the axial direction of the photoreceptor drum 11.

[0034] The cover member 62 is attached to the upper part of the housing body 20. The cover member 62 is detachably attached to the support frame 61. The cover member 62 is supported so as to be slidable in the left-right direction D3 (sliding direction) relative to the support frame 61. The cover member 62 is attached to the support frame 61 with the light guide member 72 supported by the support frame 61. In other words, the light guide member 72 is housed in the accommodation space formed between the cover member 62 and the support frame 61 when the cover member 62 is attached to the support frame 61. As a result, the cover member 62 covers the light guide member 72 and blocks out external light.

[0035] The cover member 62 has two engaging hooks 621 formed thereon. The engaging hooks 621 are hooks that protrude downward from the rear edge of the cover member 62 and are bent to the right in a hook shape. The support frame 61 has two engaging pieces 611 formed thereon that can engage with the engaging hooks 621. The engaging pieces 611 are rectangular plate-shaped members that protrude rearward from the rear end of the support frame 61. The cover member 62 is positioned so that the engaging hooks 621 are located to the left of the engaging pieces 611, and then the cover member 62 is slid to the right, causing the engaging hooks 621 to engage with the engaging pieces 611. This engages the cover member 62 with the support frame 61, preventing it from coming off upward.

[0036] Furthermore, as shown in Figure 7, an engagement hook 625 (an example of an engagement part of the present invention) is formed on the right end portion 624 of the cover member 62. The right end portion 624 is the right end of the rear end portion of the cover member 62. The engagement hook 625 protrudes to the right from the right end portion 624.

[0037] The engaging hook 625 forms a snap-fit ​​structure with respect to the side plate 201. The engaging hook 625 has an arm portion 626 that protrudes to the right from the right end portion 624, and a hook-shaped hook portion 627 formed at the tip of the arm portion 626. The hook portion 627 is bent forward in a hook shape at the tip of the arm portion 626. The arm portion 626 has flexibility that allows it to bend in the front-rear direction D2 relative to the cover member 62, and has elasticity that allows it to bend in the direction of pressure when pressed in the front-rear direction D2, and to return to its original position when the pressure is released.

[0038] The side plate 201 has an engaging piece 203 (an example of the engaged portion of the present invention) that can engage with the engaging hook 625. The engaging piece 203 is formed at the rear end of the side plate 201. The engaging piece 203 is provided on the side plate 201 at a position corresponding to the engaging hook 625.

[0039] With the engaging hook 621 engaged with the engaging piece 611, when the cover member 62 is slid to the right, the engaging hook 625 comes into contact with the engaging piece 203 of the side plate 201. As it slides further to the right, the arm portion 626 of the engaging hook 625 is bent backward, and the hook portion 627 moves over the engaging piece 203 and is positioned to the right of the engaging piece 203. In this state, the engaging hook 625 engages with the engaging piece 203. In other words, the engaging hook 625 and the engaging piece 203 engage in the left-right direction D3. To put it another way, the direction of engagement between the engaging hook 625 and the engaging piece 203 coincides with the direction in which the cover member 62 slides relative to the support frame 61. As a result, the cover member 62 engages with the support frame 61 so that it cannot slide to the left.

[0040] As shown in Figure 6, the pressing member 85 is provided on the support frame 61. With the cover member 62 attached to the support frame 61, the pressing member 85 elastically presses the end face 723 (input surface) of the left end 722 (an example of the other end of the present invention) of the left side in the left-right direction D3 (longitudinal direction) of the light guide member 72 in the pressing direction D31 (rightward direction). In other words, with the light guide member 72 attached to the support frame 61 and the cover member 62 attached to the support frame 61, the pressing member 85 applies a biasing force to the left end 722 that biases the light guide member 72 in the pressing direction D31 (rightward direction). The pressing member 85 is, for example, an elastic material such as silicone rubber, a sponge, or a spring. Note that the pressing direction 85 corresponds to the contact direction of the present invention.

[0041] As shown in Figure 8, a retaining member 74 is formed at the left end of the support frame 61. The retaining member 74 protrudes upward from the upper surface of the support frame 61. The retaining member 74 is a member that supports the left end 722 of the light guide member 72 and has a support groove 741 that is open on the upper side. The left end 722 of the light guide member 72 is inserted into this support groove 741 and supported.

[0042] Figure 9 is a rearward cross-sectional view of the drum unit 18 when it is cut in a vertical plane behind the light guide member 72. Figure 10 is a magnified view of the main part X in Figure 9. As shown in Figure 10, the pressing member 85 is positioned to the left of the holding member 74, and more specifically, is positioned in a compressed state between the holding member 74 and the left side wall 628 of the cover member 62 (an example of the opposing part of the present invention) when the cover member 62 is attached to the support frame 61.

[0043] The left side wall 628 is a plate-shaped side wall extending downward from the left end of the upper surface of the cover member 62. With the cover member 62 attached to the housing body 20, the left side wall 628 faces the end face 723 of the left end 722 of the light guide member 72.

[0044] Because the pressing member 85 is positioned in this manner, when the cover member 62 is slid to the right to engage the engaging hook 625 (see Figure 7) and the engaging piece 203 (see Figure 7), the left wall 628 presses the pressing member 85 in the pressing direction D31. As a result, the pressing member 85 is compressed by the left wall 628. Then, the engagement of the engaging hook 625 and the engaging piece 203 maintains the compressed state of the pressing member 85. Because the pressing member 85 is positioned in this manner, the compressed pressing member 85 can impart a biasing force to the left end 722 that presses the light guide member 72 in the pressing direction D31. In other words, the restoring force of the pressing member 85 presses the left end 722 of the light guide member 72 in the pressing direction D31.

[0045] Incidentally, in the static elimination unit 14, the positioning accuracy between the light-emitting element 711 of the light source substrate 71 and the incident surface 77 of the light guide member 72 is important in order to stabilize the intensity of the static elimination light L1 irradiated onto the surface of the photoreceptor drum 11. If the positioning accuracy is low, variations will occur in the intensity of the static elimination light L1. Furthermore, even if the positional relationship between the light-emitting element 711 and the incident surface 77 of the light guide member 72 is appropriate, if the assembly accuracy of the light source substrate 71, the light guide member 72, and the support members that support them is low, variations may occur in the intensity of the static elimination light L1. In addition, in conventional methods of assembling multiple components such as the light source substrate 71, the light guide member 72, and other components to the support member, the assembly tolerances of each component accumulate, and the assembly accuracy may decrease due to these accumulated tolerances. In contrast, in this embodiment, as described later, the light guide member 72 and the light source substrate 71 are positioned, thereby improving the positioning accuracy between the light-emitting element 711 of the light source substrate 71 and the incident surface 77 of the light guide member 72, as well as improving the assembly accuracy of each component, including the light source substrate 71 and the light guide member 72.

[0046] In this embodiment, the light guide member 72 is biased in the pressing direction D31 by the pressing member 85, so that the pair of protrusions 76 (an example of the first contact portion of the present invention, see Figure 8) provided on the light guide member 72 are positioned in contact with the side plate 201 at a first reference position (an example of the first reference position of the present invention). As a result, the light guide member 72 is stably held at the first reference position.

[0047] Figure 11 shows the internal configuration of the right end of the drum unit 18. In Figure 1, the side cover 63 is not shown. As shown in Figure 11, the side plate 201 has a retaining hole 201A for holding the right end 721 of the other side (right side) of the light guide member 72 which is supported by the support frame 61. The right end 721 of the light guide member 72 is inserted through the retaining hole 201A, thereby supporting the right end 721 of the light guide member 72.

[0048] The light guide member 72 has a flat incident surface 77 (an example of the light incident surface of the present invention) at its rightmost end 721 (an example of one end of the present invention) in the left-right direction D3 (the longitudinal direction of the light guide member 72). Light from the light source substrate 71 is incident on the incident surface 77. The light guide member 72 also has an exit surface (not shown) that emits light in a direction intersecting its longitudinal direction and toward region P1 in the photoreceptor drum 11. The exit surface is provided on the front side of the light guide member 72.

[0049] In this embodiment, the front exit surface of the light guide member 72 is formed to be semicircular or arc-shaped when viewed from the side. The exit surface of the light guide member 72 is an arc-shaped curved surface (arc surface) that extends along the longitudinal direction.

[0050] Multiple transmissive and reflective sections (not shown) are formed inside the light guide member 72 along its longitudinal direction. When light enters the inside of the light guide member 72 from the incident surface 77 and enters the transmissive and reflective sections, a portion of the incident light is reflected by the transmissive and reflective sections and emitted forward from the exit surface as static elimination light L1 (see Figure 2). This static elimination light L1 is irradiated onto region P1 (see Figure 2).

[0051] Figure 12 is a perspective view showing the right side cover 63 of the drum unit 18 and the configuration inside it. As shown in Figure 12, the light source substrate 71 is mounted on the inner surface of the side cover 63, and more specifically, is located on the upper part of the inner surface. The light source substrate 71 has a light-emitting element 711 that emits light to discharge the photoreceptor drum 11. The light-emitting element 711 emits light toward the incident surface 77 (see Figure 13) of the light guide member 72. The light source substrate 71 is an LED light source in which a light-emitting element 711 such as an LED element is mounted on the mounting surface of a rectangular substrate 712. The light source substrate 71 is located between the side plate 201 (see Figure 11) and the side cover 63.

[0052] The light source substrate 71 is provided on the inner surface of the side cover 63 such that the light-emitting element 711 faces the incident surface 77. Light emitted from the light-emitting element 711 of the light source substrate 71 is incident on the incident surface 77 (see Figure 13) on one side in the longitudinal direction of the light guide member 72. The light that has been incident on the incident surface 77 then travels through the interior of the light guide member 72 to the other side in the longitudinal direction, is reflected by the transmission and reflection section, and is emitted from the emission surface.

[0053] As shown in Figure 11, a pair of protrusions 76 projecting in the vertical direction D1 are provided near the right end 721 of the light guide member 72. Each protrusion 76 acts as a stopper, preventing the light guide member 72 from moving to the right from a predetermined first reference position when the light guide member 72 is pressed to the right by the pressing member 85. One protrusion 76 projects upward from the upper end of the light guide member 72, and the other protrusion 76 projects downward from the lower end of the light guide member 72.

[0054] The light guide member 72, supported by the support frame 61, has its right end portion 721 inserted into the holding hole 201A of the side plate 201. In this state, the right end portion 721 is held by the holding hole 201A. Then, with the right end portion 721 held by the holding hole 201A, when the light guide member 72 is pushed to the right (pressing direction D31), the projection 76 comes into contact with the peripheral edge of the holding hole 201A (an example of the contact portion of the present invention). As a result, the displacement of the light guide member 72 to the right from the first reference position is restricted by the projection 76 and the peripheral edge of the holding hole 201A. In other words, the light guide member 72 is positioned at the predetermined first reference position. To put it another way, the incident surface 77 of the right end portion 721 of the light guide member 72 is positioned at the predetermined first reference position.

[0055] As shown in Figure 11, the positioning mechanism 80 is provided in the housing 19. The positioning mechanism 80 positions the light-emitting element 711 of the light source substrate 71 to a predetermined second reference position (an example of the second reference position in the present invention) with respect to the incident surface 77 of the light guide member 72. The second reference position is a position where the gap between the incident surface 77 of the light guide member 72 positioned at the first reference position and the light-emitting element 711 is a predetermined reference interval.

[0056] Figure 13 is an enlarged cross-sectional view of the main part XIII in Figure 9, showing the configuration of the right end portion 721 of the light guide member 72 and the area around the light source substrate 71. As shown in Figure 13, the positioning mechanism 80 has a contact pin 81 (an example of the second contact portion of the present invention) and an elastic member 82 (an example of the second biasing portion of the present invention).

[0057] The contact pin 81 is the portion that contacts the mounting surface of the light-emitting element 711 on the light source substrate 71. The contact pin 81 is erected on the right side of the side plate 201. Two contact pins 81 are provided on the side plate 201. Each contact pin 81 is separated in the vertical direction D1 and both protrude perpendicularly to the right from the right side of the side plate 201. On the outer circumferential surface of the contact pin 81, at least one rib 83 extends in the direction of protrusion of the contact pin 81 from the base end on the side plate 201 side.

[0058] A boss 92 is provided on the inner surface of the side cover 63. A retaining plate 91 made of sheet metal is fixed to the inner surface of the side cover 63 via the boss 92. The retaining plate 91 is fixed to the boss 92 by screws or the like. As shown in Figures 11 and 13, an elastic member 82 is attached to the surface of the retaining plate 91. The elastic member 82 is an elastic material such as silicone rubber, sponge material, or spring. The elastic member 82 is pressed when the side cover 63 is attached to the side plate 201. Then, when the side cover 63 is attached to the side plate 201, it contracts and elastically presses the light source substrate 71 toward the incident surface 77 side (left side) of the light guide member 72. In this embodiment, the elastic member 82 is a sponge material formed in the shape of a rectangular parallelepiped. One side of the elastic member 82 (right side) is fixed to the surface of the retaining plate 91 by an adhesive such as double-sided tape. Furthermore, the substrate 712 of the light source substrate 71 is fixed to the other side (left side) of the elastic member 82 by an adhesive such as double-sided tape.

[0059] Furthermore, as shown in Figure 12, the side cover 63 has two support arms 95 with hooks formed at their tips. The support arms 95 protrude vertically from the inner surface of the side cover 63, and the hooks at their tips engage with the edge of the substrate 712 of the light source substrate 71. As a result, the light source substrate 71 can be displaced in a direction perpendicular to the inner surface (the direction of contraction of the elastic member 82) within the contraction range of the elastic member 82.

[0060] As shown in Figure 12, the substrate 712 has two engagement holes 93. The engagement holes 93 are located at positions corresponding to each contact pin 81 (see Figure 13). The engagement holes 93 are located at positions separated by a vertical direction D1 on the substrate 712. When the side cover 63 is attached to the side plate 201, the tips of the contact pins 81 are inserted into the corresponding engagement holes 93. As the side cover 63 is attached and fixed to the side plate 201, the ribs 83 of the contact pins 81 come into contact with the periphery of the engagement holes 93, pressing the substrate 712 to the right. On the other hand, the substrate 712 is pressed to the left by the biasing force from the elastic member 82. In this way, the elastic member 82 contracts due to the pressing force from the contact pins 81, and the elastic force generated by the contraction of the elastic member 82 presses the light source substrate 71 toward the light guide member 72 side (left side). As a result, the light-emitting element 711 of the light source substrate 71 is positioned at the second reference position.

[0061] By positioning the light source substrate 71 and the light guide member 72 in this manner, the positioning accuracy between the light-emitting element 711 of the light source substrate 71 attached to the side cover 63 and the incident surface 77 of the light guide member 72 supported by the support frame 61 of the housing 19 can be improved.

[0062] As shown in Figure 12, in this embodiment, a connector board 96 with connector members 97 and 98 mounted on it is attached to the inner surface of the side cover 63. The connector members 97 and 98 are components for relaying the power supplied to the light-emitting element 711 of the light source board 71, and both are mounted on a common board 99. The connector board 96 is located at the lower part of the inner surface of the side cover 63. In this embodiment, the assembly direction of the light source board 71 and the connector board 96 to the side cover 63 coincides with the mounting direction of the side cover 63 to the side plate 201 of the housing 19. In other words, both the light source board 71 and the connector board 96 are assembled along a direction perpendicular to the inner surface of the side cover 63 (left-right direction D3).

[0063] Furthermore, as described above, the mounting direction of the cover member 62, which covers the light guide member 72 and positions the light guide member 72 at the first reference position, is also along the left-right direction D3.

[0064] In this way, the assembly direction of each component attached to the side cover 63 is the same, and furthermore, the assembly direction of the cover member 62 to the support frame 61 is also the same, which makes the assembly process of each component easier and improves the assembly accuracy of the components after assembly.

[0065] In the above-described embodiment, a configuration in which a light source substrate 71, a light guide member 72, and a positioning mechanism 80 are provided on the drum unit 18 was illustrated, but the present invention is not limited to this configuration. For example, the present invention can also be considered as a light guide device that is not integrally provided on the drum unit 18, but comprises a light source substrate 71, a light guide member 72, and a positioning mechanism 80. Furthermore, in a scan unit of an image reading device that reads an image of a document based on reflected light from an object to be illuminated, such as a document, the present invention can be considered as a light guide device that irradiates light onto the reading surface (irradiation surface) of the document and guides the light to the document, or it can be considered as an image reading device that includes such a light guide device in its scan unit. [Explanation of Symbols]

[0066] 10: Image forming apparatus 11: Photoconductor Drum 14: Static elimination unit 15: Primary transfer roller 16: Cleaning Department 18: Drum Unit 19: Housing 20: Housing body 61: Support frame 62: Cover component 63: Side cover 71: Light source substrate 72: Light guide member 74: Retaining member 76: Protrusion 77:Incidence plane 80: Positioning mechanism 81: Contact pin 82: Elastic member 83: Rib 85: Pressing member 91: Holding plate 92: Boss 93: Engagement hole 95: Support arm 96: Connector board 97: Connector component 98: Connector component 99: Circuit board 201: Side Plate 201A: Retaining hole 202: Side Plate 203: Engaging piece 611: Engaging piece 621: Engaging hook 624: Right end 625: Engaging hook 626: Arm section 627: Hook part 628: Left side wall

Claims

1. Long support members, A light guide member is supported on one side of the support member in a direction intersecting the longitudinal direction, has a shape that is long in the same direction as the longitudinal direction of the support member, and has a light incident surface into which light is incident, A first contact portion is provided on the light guide member and, by contacting the contact portion of the support member, positions the light guide member at a predetermined first reference position on the support member, A cover member is attached to one side of the support member and covers the entire longitudinal portion of the light guide member, With the cover member attached to the support member, the first biasing member biases the light guide member in a contact direction that is in the direction in which the first contact portion contacts the portion to be contacted and is along the longitudinal direction of the light guide member, Equipped with, The cover member is A light guide device having an engaging portion that engages with the engaged portion of the support member while generating a biasing force in the contact direction in the first biasing portion.

2. The light guide member has the light incident surface at one end in its longitudinal direction and the input surface to which the biasing force is applied at the other end. The light guide device according to claim 1, wherein the cover member is supported by the support member so as to be slidable in the longitudinal direction of the light guide member, has an opposing portion facing the input surface, and the first biasing portion is provided between the opposing portion and the input surface, and the first biasing portion is pressed in the contact direction by the opposing portion when the engaging portion engages with the engaged portion.

3. The light guide device according to claim 2, wherein the engagement direction of the engaging portion with respect to the engaged portion coincides with the sliding direction of the cover member with respect to the support member.

4. The light guide device according to any one of claims 1 to 3, wherein the engaging portion has a snap-fit ​​structure that engages with the engaged portion by a snap-fit.

5. The light guide device according to any one of claims 1 to 4, wherein the first biasing portion is an elastic member having elasticity in the contact direction.

6. The light guide device according to any one of claims 1 to 5, wherein the cover member is configured to be detachably attached to one side of the support member.

7. A side member attached to the support member, A light source substrate having a light-emitting element provided on the side member and emitting light toward the light incident surface, The support member is provided with a second contact portion that contacts the light source substrate, The light guide device according to any one of claims 1 to 6, further comprising: a second biasing unit provided on the side member, which biases the light source substrate toward the light guide member while the side member is attached to the support member, thereby positioning the light-emitting element at a predetermined second reference position on the support member.

8. The second biasing portion is an elastic member having elasticity and is contractible in response to the pressing force received by the second contact portion. The light guide device according to claim 7, wherein the light source substrate is supported by the side member so as to be displaceable in the contraction direction of the second biasing portion.

9. The side member is further provided with a connector member for supplying power to the light-emitting element, The assembly direction of the light source substrate and the connector member to the side member coincides with the mounting direction of the side member to the support member, as described in claim 7 or 8. Device.

10. A drum unit used by being attached to an image forming apparatus, A long support member that rotatably supports the photosensitive drum, A light guide member is supported on one side of the support member in a direction intersecting the longitudinal direction, has a shape that is long in the same direction as the longitudinal direction of the support member, has a light incident surface into which light is incident, and deflects the light incident on the light incident surface to irradiate the photoreceptor drum with light, A first contact portion is provided on the light guide member and, by contacting the contact portion of the support member, positions the light guide member at a predetermined first reference position on the support member, A cover member is attached to one side of the support member and covers the entire longitudinal portion of the light guide member, With the cover member attached to the support member, the first biasing member biases the light guide member in a contact direction that is in the direction in which the first contact portion contacts the portion to be contacted and is along the longitudinal direction of the light guide member, Equipped with, The cover member is A drum unit having an engaging portion that engages with the engaged portion of the support member while generating a biasing force in the contact direction in the first biasing portion.

11. An image forming apparatus comprising the drum unit described in claim 10, wherein an electrostatic latent image formed on the surface of the photoreceptor drum is developed with a developer.

12. A light guide device according to any one of claims 1 to 9, An image forming apparatus comprising: a photoreceptor drum to which light guided by the light guide device is irradiated.

13. A light guide device according to any one of claims 1 to 9, The system comprises an object to be irradiated with light guided by the aforementioned light guide device, An image reading device that reads image data of the irradiated surface of the irradiated object based on the reflected light from the irradiated object.

Images