Image forming apparatus

Abstract

To suppress air flowing to an exposure unit side without passing through a cooling space in a configuration in which external air is passed to the cooling space by a duct.SOLUTION: A first seal member 201 is disposed in a gap between the developing duct 1051 and the developing support tray 301. In the developing duct 1051, a second seal member 202 is disposed on the downstream side of the first seal member 201. The first seal member 201 is elastically compressed in the vertical direction to seal the gap between the developing duct 1051 and the developing support tray 301, thereby suppressing a part of the air passing through the developing duct 1051 from flowing into the apparatus body from the upstream side in the insertion direction and both end sides in the width direction. The second seal member 202 is elastically compressed in the insertion direction between the developing duct 1051 and the first rail disposed on the exposure unit side, so that the gap between the developing duct 1051 and the first rail is sealed, and a part of the air passing through the developing duct 1051 is prevented from flowing to the exposure unit side.SELECTED DRAWING: Figure 19

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus such as a printer, a copying machine, a facsimile machine, or a multifunction machine. [Background technology]

[0002] In an image forming apparatus, an electrostatic latent image is formed on a charged photosensitive drum by an exposure unit having a plurality of light-emitting elements, such as LEDs or organic EL elements, arranged along the rotational axis of the photosensitive drum. The exposure unit has a lens array in which a plurality of lenses are arranged along the rotational axis (longitudinal direction) of the photosensitive drum to focus light emitted from each light-emitting element onto the surface of the photosensitive drum. Because the focal length of this lens array is extremely short, the exposure unit is located close to the photosensitive drum.

[0003] The exposure unit is located close to a developing device that develops an electrostatic latent image formed on a photosensitive drum into a toner image, and heat generated by the exposure unit can affect the toner contained in the developing device. To mitigate the effects of heat on the toner, the developing device is cooled by supplying air from outside the image forming device (see Patent Document 1). In the device described in Patent Document 1, the developing device is supported so as to be insertable and removable in the longitudinal direction relative to the cartridge tray, and a cooling space is formed between the developing device and the cartridge tray through which air supplied from outside the device body passes. The image forming device also has an inner door that can be opened and closed relative to the device body, and a connection port (duct) is provided inside the inner door to allow external air to pass into the cooling space. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-156782 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the past, there was a risk that some of the supplied air would flow into the main body of the device through the gap between the connection port (duct) and the cartridge tray without passing through the cooling space. In particular, the air flowing inside the main body of the device toward the exposure unit is likely to scatter toner, and the scattered toner may adhere to the exposure unit and cause image defects.

[0006] In view of the above problems, the present invention aims to provide an image forming device that, when configured such that external air passes through a duct provided in the developing device into a cooling space formed between the developing device and a cartridge tray, can suppress air from flowing from the duct to the exposure section without passing through the cooling space. [Means for solving the problem]

[0007] An image forming apparatus according to one embodiment of the present invention is an image forming apparatus comprising: an apparatus main body; a photosensitive member; an exposure unit that exposes the surface of the photosensitive member to light and that includes a plurality of light-emitting elements that are arranged adjacent to the photosensitive member and aligned in the longitudinal direction of the photosensitive member; and a lens array that includes a plurality of lenses for focusing the light emitted from the light-emitting elements onto the surface of the photosensitive member, thereby forming an electrostatic latent image; a developing device that is detachable from the apparatus main body, that is arranged adjacent to the exposure unit in a width direction that intersects the longitudinal direction when attached to the apparatus main body, and that develops the electrostatic latent image on the photosensitive member into a toner image; and a support unit that supports the developing device so that it can be inserted and removed along the longitudinal direction when attaching and detaching the developing device to and from the apparatus main body, the support unit having a main body portion and first and second rails that are arranged along the longitudinal direction on the surface of the main body that faces the developing device. The developing device is characterized by comprising: a duct provided in the developing device, which, when the developing device is attached to the device main body, allows air to flow from the upstream side of the developing device into a space surrounded by the developing device, the main body, the first rail, and the second rail in the insertion direction of the developing device; a first sealing member that, when the developing device is attached to the device main body, seals between a first surface of the duct on the main body side and a second surface of the main body that is upstream of the upstream ends of the first rail and the second rail in the insertion direction; and a second sealing member that is provided downstream of the first sealing member in the insertion direction and, when the developing device is attached to the device main body, seals between the first surface and the upstream end of the first rail in the insertion direction that is located on the exposure section side of the first rail and the second rail in the width direction. [Effects of the Invention]

[0008] According to the present invention, in a configuration in which external air is passed through a duct provided in the developing device into the space formed between the developing device and the support part, it is possible to suppress air flowing from the duct to the exposure part side without passing through the space. [Brief explanation of the drawings]

[0009] [Figure 1]1 is an external perspective view showing an image forming apparatus according to an embodiment of the present invention; [Figure 2] FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus. [Figure 3] FIG. 4 is a schematic diagram showing the image forming apparatus when the developing sleeve and the exposure unit are in the separated position. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. 4 is a perspective view showing the bottom surface of the exposure unit. [Figure 7] FIG. [Figure 8] FIG. 4 is an enlarged view showing the front cover and inner door in an open state. [Figure 9] FIG. 4 is an enlarged view showing the state in which the drum unit is removed. [Figure 10] FIG. 4 is an enlarged view showing a state in which the development unit is removed. [Figure 11] FIG. 10 is a perspective view showing a connected state of a plurality of cartridge trays connected in parallel. [Figure 12] FIG. 2 is a cross-sectional view showing the drum unit, the developing unit, the exposure unit, and the cartridge tray. [Figure 13] FIG. [Figure 14] FIG. 4 is a perspective view showing the cartridge tray with the inner door open. [Figure 15] FIG. 10 is a side view showing the cartridge tray with the inner door closed. [Figure 16] FIG. 4 is a side view showing the cartridge tray with the inner door open. [Figure 17] 1A and 1B are diagrams for explaining the contact and separation mechanism of the exposure unit, in which FIG. 1A shows the exposure unit at the exposure position, and FIG. 1B shows the exposure unit at the separation position. [Figure 18] FIG. [Figure 19] FIG. 4 is an enlarged cross-sectional view of a developing duct portion. [Figure 20] 20 is a cross-sectional view seen from the front as viewed in the direction of arrow CC in FIG. 19. [Figure 21] 19 is a cross-sectional view seen from below as indicated by the arrow DD in FIG. 18. [Figure 22] FIG. 3 is a perspective view showing the arrangement of a first seal member, a second seal member, and a third seal member. [Figure 23] 19 is a cross-sectional view seen from below as indicated by arrows EE in FIG. 18. [Figure 24] FIG. 10 is a top view of the developer support tray showing the fourth seal member, the fifth seal member, the sixth seal member, and the seventh seal member. [Figure 25] FIG. 10 is a bottom view of the developer support tray, showing the fifth seal member and the seventh seal member. [Figure 26] 20 is a cross-sectional view seen from the front as indicated by the arrow FF in FIG. 19. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Image forming device] The present embodiment will be described below. First, an overview of the image forming apparatus of the present embodiment will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, the image forming apparatus 100 of the present embodiment is a so-called internal discharge type image forming apparatus. That is, the image forming apparatus 100 includes an apparatus main body 100A and an original reading device 200 that reads image information from an original, and an output tray 21 that stacks sheets S (recording materials) discharged from the apparatus main body 100A is formed between the apparatus main body 100A and the original reading device 200. The image forming apparatus 100 forms a toner image on the sheet S in accordance with an image signal sent from the original reading device 200 or an external device (not shown) such as a personal computer.

[0011] An operation unit 46 having a display unit capable of displaying various information and keys for inputting various information in response to user operation is disposed on the front side of the device main body 100A. In this specification, the side from which a user inserts and removes a developing unit (described below) that is removably mounted in the device main body 100A from the outside of the device main body 100A is referred to as the "front (front face)," and the opposite side is referred to as the "rear (back face)." In addition, the left side when viewing the image forming device 100 from the front is referred to as the "left," and the right side when viewing the image forming device 100 from the front is referred to as the "right."

[0012] Apparatus main body 100A is made up of a front plate provided on the front side of image forming apparatus 100, a rear plate provided on the rear side that supports each unit together with the front plate, stays connecting these front and rear plates, pillars supporting the front plate, and other metal plates, and is covered by an exterior cover that constitutes the exterior of image forming apparatus 100. As exterior covers, a front cover 101, multiple cassette covers 103, and an upper front cover 104 are arranged on the front side. In addition, side covers are arranged on the left and right side sides, and a rear cover is arranged on the rear side.

[0013] 2 and 3 includes four image forming units 1Y, 1M, 1C, and 1K that form toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K). Note that the configurations of the image forming units 1Y, 1M, 1C, and 1K that form toner images of each color are almost the same, so in FIGS. 2 and 3, only the magenta image forming unit 1M is given a reference numeral, and the image forming unit 1M will be used as an example for explanation.

[0014] The image forming section 1M has two units, a drum unit 23 and a developing unit 24 (see FIG. 3). The drum unit 23 and the developing unit 24 are supported by a cartridge tray 30 and are provided so as to be insertable into and removable from the cartridge tray 30 from the front side of the apparatus main body 100A so as to be guided in the direction of the rotation axis (longitudinal direction) of the photosensitive drum 2 that rotates around a rotation axis. The drum unit 23 has the photosensitive drum 2 as a photosensitive member, a charging roller 3 that charges the photosensitive drum 2, and a drum cleaner unit (not shown).

[0015] The developing unit 24 as a developing device is disposed in a developing container that contains a developer containing toner, and includes a developing sleeve 5 that supplies toner to the photosensitive drum 2 to form a toner image, and a conveying screw 7 that conveys the toner while stirring it. In the rotation direction of the photosensitive drum 2, an exposure unit 4 that exposes the surface of the photosensitive drum 2 to light to form an electrostatic latent image is disposed between the drum unit 23 and the developing unit 24. The exposure unit 4 as an exposure section is supported by a cartridge tray 30.

[0016] An intermediate transfer belt unit 8 is disposed above the image forming stations 1Y to 1K. The intermediate transfer belt unit 8 has four primary transfer rollers 6 disposed opposite the photosensitive drums 2 of each color, and one endless intermediate transfer belt 9. Toner bottles 22Y to 22K containing replenishment toner to be supplied to the developing units 24 are provided above the intermediate transfer belt unit 8 so as to be detachable from a toner supply mechanism (not shown). The toner supply mechanism supplies the appropriate amount of toner from the toner bottles 22Y to 22K to each developing unit 24 of the corresponding image forming stations 1Y to 1K at the appropriate time. Sheet cassettes 12A and 12B containing sheets S are disposed below the image forming stations 1Y to 1K.

[0017] <Image formation process> Next, the image forming process on the sheet S in the image forming apparatus 100 will be described. In each of the image forming units 1Y to 1K, the surface of the photosensitive drum 2, which is driven to rotate by a motor (not shown), is uniformly charged by a charging roller 3 pressed against the photosensitive drum 2. Thereafter, an exposure unit 4, which is driven based on a signal of image information, irradiates the surface of the photosensitive drum 2 with light, and an electrostatic latent image is formed on the surface of the photosensitive drum 2. The electrostatic latent image formed on the photosensitive drum 1 is developed into a toner image by a developing unit 24. The developing unit 24 develops the electrostatic latent image with toner contained in a developer, and forms a toner image on the photosensitive drum 1.

[0018] In the developing unit 24, a high voltage is applied to the developing sleeve 5, and the toner, which is charged by the stirring of the conveying screw 7, is uniformly coated on the surface of the developing sleeve 5. The conveying screw 7 is rotated at a relatively high speed compared to the rotational speed of the developing sleeve 5 and the photosensitive drum 2, and as a result, the toner is evenly coated on the surface of the developing sleeve 5.

[0019] The toner image formed on the photosensitive drum 2 (photoconductor) is primarily transferred from the photosensitive drum 2 to the intermediate transfer belt 9 by applying a primary transfer voltage to a primary transfer roller 6 disposed opposite the image forming units 1Y to 1K with the intermediate transfer belt 9 interposed therebetween. A drum cleaner unit (not shown) collects residual toner remaining on the photosensitive drum 2 after the primary transfer.

[0020] Inside the apparatus main body 100A of the image forming apparatus 100, a sheet transport path for transporting the sheet S from bottom to top is provided on the right side. Arranged on this sheet transport path from bottom to top are a supply roller pair 13, a registration roller pair 15, a secondary transfer outer roller 16, a fixing unit 19, and a discharge roller pair 20. The secondary transfer outer roller 16 abuts against the secondary transfer inner roller 10, which is arranged inside the intermediate transfer belt 9, with a predetermined pressure across the intermediate transfer belt 9, thereby forming a secondary transfer nip portion 17.

[0021] Sheets S stored in sheet cassettes 12A and 12B are supplied one by one from either sheet cassette 12A or 12B to a sheet conveying path by driving supply roller pair 13 at a predetermined control timing. Sheet S supplied by supply roller pair 13 is conveyed to registration roller pair 15 arranged midway along the conveying path. Then, registration roller pair 15 corrects skew and timing of sheet S, and sends sheet S to secondary transfer nip portion 17. Secondary transfer nip portion 17 is formed by secondary transfer inner roller 10 and secondary transfer outer roller 16 that face each other across intermediate transfer belt 9, and is a nip portion that transfers a toner image from intermediate transfer belt 9 onto sheet S by applying a predetermined pressure and secondary transfer voltage.

[0022] The image formation processes for each color, which are processed in parallel by the image forming units 1Y to 1K for each color described above, are performed in a timed manner to sequentially superimpose the image onto the toner image of the color that was primarily transferred onto the intermediate transfer belt 9 upstream in the movement direction. As a result, a full-color toner image is formed on the intermediate transfer belt 9 and is transported to the secondary transfer nip portion 17. At the secondary transfer nip portion 17, the timing of the sheet S and the full-color toner image coincides, and secondary transfer is performed in which the toner image is transferred from the intermediate transfer belt 9 to the sheet S. The sheet S is then transported to the fuser 19, where the toner image is fixed to the sheet S by applying heat and pressure. After passing through the fuser 19, the sheet S is transported to the discharge roller pair 20 and discharged onto the discharge tray 21 by the discharge roller pair 20.

[0023] In this embodiment, the drum unit 23 and the developing unit 24 deteriorate due to repeated image formation processes and require replacement or maintenance. The drum unit 23 and the developing unit 24 are in the form of cartridges so that the user can easily insert and remove them from the apparatus main body 100A for replacement or maintenance. Figure 3 shows the arrangement of the drum unit 23, the developing unit 24, and the exposure unit 4 when inserting and removing the drum unit 23 and the developing unit 24.

[0024] 3, when inserting or removing the drum unit 23 or the developing unit 24, the developing unit 24 and the exposure unit 4 are separated from the drum unit 23, which differs from the state shown in FIG. 2. This is because if the developing unit 24 and the exposure unit 4 were positioned close to the photosensitive drum 2 when inserting or removing the drum unit 23 or the developing unit 24, dynamic interference during insertion or removal of the drum unit 23 or the developing unit 24 could damage the units or make it impossible to remove them. For this reason, the user is allowed to separate the developing unit 24 and the exposure unit 4 before inserting or removing the drum unit 23 or the developing unit 24.

[0025] <Exposure unit> Next, the exposure unit 4 will be described with reference to Fig. 3 and Fig. 4 to Fig. 6. As shown in Fig. 4, the exposure unit 4 has a mounting substrate 50, a plurality of light-emitting elements 51 arranged in the longitudinal direction on one side of the mounting substrate 50, and a lens array 52 in which a plurality of lenses that transmit light emitted from the light-emitting elements 51 are arranged. The light-emitting elements 51 are, for example, light-emitting diodes (Light Emitting Diodes) or organic electroluminescence (EL) elements. The lens array 52 has a plurality of lenses arranged in the direction in which the light-emitting elements 51 are arranged.

[0026] The mounting substrate 50 and the lens array 52 have a plurality of light-emitting elements 51 and a plurality of lenses arranged thereon, respectively, across the exposure range in the direction of the rotation axis of the photosensitive drum 2. Therefore, as shown in FIG. 5 , the mounting substrate 50 and the lens array 52 are formed in a shape that extends along the direction of the rotation axis of the photosensitive drum 2. The mounting substrate 50 and the lens array 52 are held in place by being adhered to a housing 54 with high precision using an adhesive. The housing 54 is required to have high rigidity, and in this embodiment, a metal plate such as a galvanized steel plate or a cold-rolled steel plate bent into a substantially U-shaped cross section is used. The lens array 52 and the mounting substrate 50 are inserted into the housing 54 in order from the open side of the U and fixed with an adhesive.

[0027] The housing 54 further has a housing support member 55 formed in a substantially U-shaped cross section, which is provided integrally with the housing 54 on the side of the U-shaped opening. As shown in Fig. 6, an opening 55A that communicates between the inside and outside of the housing support member 55 is formed in the bottom of the housing support member 55 at a position facing the back surface opposite the front surface of the mounting substrate 50 in each housing 54. As described above, the exposure unit 4 is configured as an integrated head unit by the mounting substrate 50 on which the plurality of light-emitting elements 51 are mounted, the lens array 52 in which the plurality of lenses are arranged in parallel, the housing 54, and the housing support member 55.

[0028] Next, the insertion and removal of the drum unit 23 and the developing unit 24 into the apparatus main body 100A will be described with reference to Figures 7 to 11. As shown in Figure 7, the image forming apparatus 100 is equipped with inner doors 102Y, 102M, 102C, and 102K (hereinafter collectively referred to as "inner door 102") that cover the front sides of both the drum unit 23 and the developing unit 24 mounted in the apparatus main body 100A. The inner door 102 is a necessary member for protecting the drum unit 23, the developing unit 24, and the exposure unit 4, and for making it difficult for the photosensitive drum 2 to be exposed to light outside the image formation process, and is disposed in a position facing the front of the units for each color so as to be able to open and close.

[0029] As shown in FIGS. 8 to 10 , one end of the inner door 102 is fixed to the front side of the cartridge tray 30 by a hinge, and the inner door 102 is rotatable relative to the cartridge tray 30 by the hinge. The developing unit 24 and the exposure unit 4 are provided so as to be movable toward and away from the drum unit 23 by a later-described moving mechanism that operates in conjunction with the opening and closing of the inner door 102. The developing unit 24 moves between a developing position where it is adjacent to the photosensitive drum 2 and can develop an electrostatic latent image, and a spaced position away from the photosensitive drum 2 for maintenance such as cleaning. The exposure unit 4 moves between an exposure position where it is adjacent to the photosensitive drum 2 and can expose the photosensitive drum 2, and a spaced position away from the photosensitive drum 2 where it does not expose the photosensitive drum 2. Note that FIGS. 8 to 10 show a state in which only the inner door 102K, which opens and closes to insert and remove the drum unit 23 and developing unit 24 provided in the black image forming unit 1K, is open.

[0030] A front cover 101 is provided at the front side of the image forming apparatus 100 so as to be able to open and close freely. One end of the front cover 101 is fixed to the front side of the apparatus body 100A of the image forming apparatus 100 by a hinge, and the front cover 101 is rotatable relative to the apparatus body 100A of the image forming apparatus 100 by the hinge. The front cover 101 is provided in front of the inner door 102 in the direction of the rotation axis of the photosensitive drum 2. The front cover 101 is an exterior cover that constitutes the external appearance of the image forming apparatus 100, covering the entirety of the multiple inner doors 102 lined up in the left-right direction when closed as shown in FIG.

[0031] 8, the front cover 101 is provided with a front door duct 41 for passing air outside the apparatus main body 100A to each developing unit 24. The front door duct 41 is provided on the back surface of the front cover 101, opposite the front surface that forms part of the exterior of the image forming apparatus 100, and extends in the left-right direction, which is the arrangement direction of the developing units 24. The front door duct 41 has openings 41a at positions corresponding to the developing units 24 of each color. The openings 41a of the front door duct 41 are provided at positions facing the inner door duct 1021 of the inner door 102 in the direction of the rotation axis of the photosensitive drum 2, and communicate with the inner door duct 1021 of the inner door 102 when the front cover 101 is closed.

[0032] The user replaces the drum unit 23 or the developing unit 24 in the following procedure. The user opens the front cover 101 as shown in FIG. 7, and then opens the inner door 102 as shown in FIG. 8, thereby removing the drum unit 23 from the apparatus main body 100A with the developing unit 24 spaced apart from the photosensitive drum 2 (see FIG. 9). Alternatively, the user can remove the developing unit 24 from the apparatus main body 100A with the developing unit 24 spaced apart from the photosensitive drum 2 (see FIG. 10). The user then inserts a new drum unit 23 or developing unit 24, closes the inner door 102, and then closes the front cover 101, thereby completing the replacement of the drum unit 23 or developing unit 24.

[0033] The cartridge tray 30 is provided for each of the image forming units 1Y to 1K (see FIG. 2), and supports the drum unit 23 and the developing unit 24 so that they can be inserted and removed along the rotation axis direction (longitudinal direction) of the photosensitive drum 2. In this embodiment, as shown in FIG. 11, four cartridge trays 30 are connected together, so that when assembling the image forming apparatus 100, the four connected cartridge trays 30 can be installed together in the apparatus main body 100A. In this way, installing the cartridge trays 30 in the connected state in the apparatus main body 100A improves the ease of assembly compared to installing the cartridge trays 30 in the apparatus main body 100A without connecting them.

[0034] <Developing unit contact / separation mechanism> The developing unit 24 is brought into contact with and separated from the drum unit 23 by a contact / separation mechanism that operates in conjunction with the opening and closing of the inner door 102. The contact / separation mechanism of the developing unit 24 will be described using Figures 12 to 16 with reference to Figure 2. As described above, the developing unit 24 and the exposure unit 4 are supported by the cartridge tray 30.

[0035] As shown in Figures 12, 13, and 14, the cartridge tray 30 has a developer support tray 301 that supports and guides the insertion and removal of the developer unit 24 along the longitudinal direction, and a drum support tray 302 that supports and guides the drum unit 23 along the longitudinal direction. The drum support tray 302 extends in the direction of the rotation axis of the photosensitive drum 2 so as to guide and support the drum unit 23 along the longitudinal direction. The developer support tray 301 as a support portion supports the developer unit 24 so that it can be inserted and removed along the longitudinal direction when the developer unit 24 is attached to or detached from the apparatus main body 100A. As shown in Figure 14, the developer support tray 301 has a main body portion 330 and first and second rails 331 and 332 that extend along the longitudinal direction on a surface 330a of the main body portion 330 facing the developer unit 24 (developing device side). In this embodiment, of the first rail 331 and the second rail 332, the first rail 331 is located on the exposure unit 4 side (exposure section side) in the width direction that intersects with the longitudinal direction.

[0036] A portion of the cartridge tray 30 is disposed directly below the developing unit 24. A cooling space 310 is formed between the developing support tray 301 and the developing unit 24, through which air supplied from outside the apparatus main body 100A can circulate in order to cool the developing unit 24. The cooling space 310 is a space surrounded by the developing unit 24, the main body 330 of the developing support tray 301, the first rail 331, and the second rail 332 when the developing unit 24 is attached to the developing support tray 301. As will be described in detail later, an opening at one end (front side) of the cooling space 310 in the longitudinal direction communicates with a developing duct 1051 of a developing duct portion 105 provided in the developing unit 24 (see, for example, FIGS. 18 and 19 ), allowing external air supplied from an inner door duct 1021 of the inner door 102 to flow in.

[0037] As shown in FIGS. 15 and 16, a developer support tray 301, a developer pressure piece (front) 32, a developer pressure piece (rear) 33, and a developer stay link 34 are provided on the cartridge tray 30. The developer pressure piece (front) 32 and the developer pressure piece (rear) 33 are fixed to the developer support tray 301 and hold and press the developer unit 24 toward the photosensitive drum 2. A developer stay link 34 engaged with an inner door 102 is fixed to the front end of the developer support tray 301. The inner door 102 has a link engagement portion 102B that engages with the developer stay link 34, which is located closer to the end than the rotation shaft 102A. Therefore, as the inner door 102 rotates, it moves in the direction of rotation of the door along a circular locus whose radius is the distance between the rotation shaft 102A and the link engagement portion 102B.

[0038] That is, as shown in FIG. 16, opening the inner door 102 causes the link engagement portion 102B to also rotate and move toward the rear of the apparatus. This causes the engaged developer stay link 34 to slide toward the rear of the apparatus in the direction of arrow R, and the two developer pressure pieces (32, 33) integrally formed through the developer support tray 301, which is a sliding member, also slide in the direction R. This means that, as shown in FIG. 16, the two developer pressure pieces (32, 33) are disengaged from the positions holding the developer unit 24, and the developer unit 24 moves due to its own weight in the direction of arrow D, which is a direction away from the photosensitive drum 2. As described above, the developer unit 24 moves away from the photosensitive drum 2 in conjunction with the opening of the inner door 102. Note that when closing the inner door 102, the developer unit 24 approaches the photosensitive drum 2 through the reverse procedure of the opening operation.

[0039] <Exposure unit contact / separation mechanism> Next, the contact / separation mechanism of the exposure unit 4 will be described with reference to Figures 17(a) and 17(b). Figure 17(a) shows the exposure unit 4 in the exposure position, and Figure 17(b) shows the exposure unit 4 in the separated position. As shown in Figures 17(a) and 17(b), the contact / separation mechanism 520 of the exposure unit 4 includes a frame body 521, a slide member 522, and a link mechanism 530. The frame body 521 is formed by bending a metal plate into a U-shape by press working. The frame body 521 is an elongated member extending in the direction of the rotation axis of the photosensitive drum 2, and both longitudinal ends are fixed to the apparatus main body 100A.

[0040] A slide member 522 is provided on one longitudinal end (front side) of the frame body 521 so as to be movable longitudinally relative to the frame body 521. When the slide member 522 moves longitudinally, link mechanisms 530 provided on both ends of the frame body 521 rotate, moving the exposure unit 4 up and down. The link mechanism 530 includes a link member 531 that connects the housing support member 55 of the exposure unit 4 to the slide member 522, and a link member 532 that connects the link member 531 to the frame body 521. As the inner door 102 opens and closes, the slide member 522 slides longitudinally relative to the frame body 521. The link members 531 and 532 rotate in conjunction with the sliding movement of the slide member 522, and the exposure unit 4 moves up and down. 17(a), when the slide member 522 is moved forward relative to the frame body 521, the link members 531 and 532 rotate in conjunction with this, and the exposure unit 4 rises to the exposure position. On the other hand, when the slide member 522 is moved rearward relative to the frame body 521, the link members 531 and 532 rotate in conjunction with this, and the exposure unit 4 falls to the separated position, as shown in FIG.

[0041] <Developing unit cooling configuration> The developing unit 24 contains a developer container containing a conveying screw 7 and toner agitated and conveyed by the conveying screw 7. The temperature of the developing unit 24 rises due to frictional heat generated by the bearing of the conveying screw 7 and the toner as it rotates at high speed. Once image formation is complete, the temperature of the developing unit 24 gradually drops. However, as image formation continues, the temperature of the developing unit 24 continues to rise as long as the heat capacity of the developing unit 24 allows. Because toner is easily melted by heat, if the temperature of the developing unit 24 rises above a predetermined temperature, the toner melts in the developing container and adheres to the developing sleeve 5, resulting in poor coating of the developing sleeve 5 and poor development. To prevent this, the developing unit 24 must be cooled to prevent the temperature from rising above a predetermined temperature. The cooling configuration for the developing unit 24 will be described using FIGS. 18 and 19, along with FIG. 8. In FIG. 18, the air flow for cooling the developing unit 24 is indicated by dotted arrows.

[0042] To generate an airflow for cooling the developing unit 24, for example, a cooling fan (not shown) is attached to the front cover 101. Air blown by the cooling fan passes from the opening 41a of the front door duct 41 to the inner door duct 1021 of the inner door 102. A developing duct portion 105 is provided in the developing unit 24 so that the air that has passed through the inner door duct 1021 is guided to the underside of the developing unit 24 and flows into the cooling space 310.

[0043] It is preferable that the size (cross-sectional area) of the inner door duct 1021 be large in order to take in more air. On the other hand, it is preferable that the gap (cooling space 310) between the upper surface of the developer support tray 301 and the bottom surface of the developing unit 24 be kept to the minimum necessary size in order to avoid an increase in the size of the image forming apparatus 100 in the vertical direction. If air is passed directly from the inner door duct 1021 to the cooling space 310, which is significantly different in size, the sudden change in size increases the air flow resistance, and this may reduce the cooling efficiency of the developing unit 24 by the external air.

[0044] <Developing duct section> Therefore, the developing unit 24 has a developing duct portion 105 at one end (front side) in the longitudinal direction. The developing duct portion 105 is provided with a developing duct 1051 that communicates with the cooling space 310 so that air flowing in from the outside in response to the operation of the cooling fan is guided into the cooling space 310 via the inner door duct 1021. The developing duct 1051 is formed so that the size on the cooling space 310 side gradually becomes smaller than the size on the inner door duct 1021 side, and is provided to suppress a decrease in the cooling efficiency of the developing unit 24 by smoothly communicating the inner door duct 1021 and the cooling space 310 without a sudden change in size. The air that flows into the cooling space 310 via the front door duct 41, the inner door duct 1021, and the developing duct 1051 flows from front to rear in the longitudinal direction to cool the developing unit 24. Thus, in the cooling configuration of the developing unit 24 according to this embodiment, the cooling space 310 formed between the developing unit 24 and the developing support tray 301 forms a flow path through which the airflow generated by the cooling fan passes.

[0045] 19, the developing duct 1051 of the developing duct portion 105 is disposed so as to partially overlap with the developing support tray 301 in the insertion direction in which the developing unit 24 is inserted into the developing support tray 301. In addition, a portion of the developing duct 1051 and the developing support tray 301 overlap with each other in the up-down direction.

[0046] In this embodiment, the developing duct 1051 has a step portion 1051b on its bottom surface. The step portion 1051b divides the bottom surface of the developing duct 1051 into a downstream surface 1051a on the downstream side in the insertion direction and an upstream surface 1051c on the upstream side in the insertion direction that protrudes downward from the downstream surface 1051a. In contrast, the main body 330 of the developing support tray 301 has a duct receiving portion 320 on the upstream side in the insertion direction that faces the bottom surface of the developing duct 1051 when the developing unit 24 is supported on the developing support tray 301. The duct receiving portion 320 is disposed upstream of the upstream ends of the first rail 331 and the second rail 332 (see FIG. 14 ) of the main body 330 in the insertion direction of the developing unit 24. The surface of duct receiving portion 320 is formed to fit along the bottom surface (downstream surface 1051a, step portion 1051b, upstream surface 1051c) of development duct 1051. In other words, step portion 320b is provided on the surface of duct receiving portion 320 so as to divide it into a first surface 320a on the downstream side in the insertion direction that faces downstream surface 1051a, and a second surface 320c on the upstream side in the insertion direction that faces upstream surface 1051c.

[0047] As described above, a step portion 1051b is formed on the bottom surface of the developing duct 1051. This is because the developing duct 1051 is preferably formed so that the size (cross-sectional area) on the cooling space 310 side gradually becomes smaller than the size (cross-sectional area) on the inner door duct 1021 side. In other words, if air is passed directly from the inner door duct 1021 to the cooling space 310, which is significantly different in size, the sudden change in size increases the air flow resistance, which can reduce the cooling efficiency of the developing unit 24. Therefore, from the perspective of air flow resistance, it is not preferable to suddenly change the size of the flow path within the developing duct 1051. Therefore, the developing duct 1051 is formed so that the size on the cooling space 310 side gradually becomes smaller than the size on the inner door duct 1021 side, and by smoothly communicating the inner door duct 1021 and the cooling space 310 without a sudden change in size, a decrease in the cooling efficiency of the developing unit 24 is suppressed.

[0048] A gap is provided between the bottom surface (downstream surface 1051a, step portion 1051b, upstream surface 1051c) of the development duct 1051 and the surface (first surface 320a, step portion 320b, second surface 320c) of the duct receiving portion 320. In this embodiment, the gap is provided to avoid dynamic interference when inserting or removing the development unit 24, which is detachably attached to the development support tray 301. Furthermore, gaps can occur due to component tolerances caused by variations in molding. However, if a gap is provided, some of the air passing through the development duct 1051 can pass through the gap and flow into the apparatus main body 100A without passing through the cooling space 310. In particular, if air flows from the exposure unit 4 side into the apparatus main body 100A, not only will the cooling efficiency of the development unit 24 decrease, but toner scattered by the air may adhere to the exposure unit 4, resulting in image defects.

[0049] Therefore, in this embodiment, in order to prevent air from leaking particularly toward the exposure unit 4 from the gap between the developing duct 1051 and the developing support tray 301, two elastic seal members, a first seal member and a second seal member, are disposed in the developing duct portion 105. These seal members will be described below using Figures 19 to 22 with reference to Figure 14.

[0050] <First seal member, second seal member> 19 and 20, in this embodiment, when the developing unit 24 is attached, the first seal member 201 seals between the upstream surface 1051c of the developing duct 1051 and a second surface 320c of the main body 330 of the developer support tray 301, the second surface 320c being located upstream of the upstream ends of the first rail 331 and the second rail 332 (see FIG. 14) in the insertion direction. The first seal member 201 is elastically compressed in the vertical direction between the upstream surface 1051c of the developing duct 1051 (first surface on the main body side) and the second surface 320c (second surface) of the main body 330. As shown in FIG. 22, the first seal member 201 is attached to the upstream surface 1051c of the developing duct 1051.

[0051] If the first seal member 201 of this embodiment were not provided, air that has passed through the developing duct 1051 could flow into the apparatus main body 100A from the upstream side in the insertion direction or both ends in the width direction through a gap between the upstream surface 1051c of the developing duct 1051 and the second surface 320c of the main body 330. Therefore, by providing the first seal member 201, even if some of the air that has passed through the developing duct 1051 flows between the upstream surface 1051c of the developing duct 1051 and the second surface 320c of the main body 330, it is possible to prevent such air from flowing into the apparatus main body 100A.

[0052] 19 and 21, the second seal member 202 is provided downstream of the first seal member 201 in the insertion direction of the developing unit 24. When the developing unit 24 is attached, the second seal member 202 seals between the downstream surface 1051a of the developing duct 1051 and the upstream end 331a in the insertion direction of the first rail 331, which is located on the exposure unit 4 side in the width direction. The second seal member 202 is attached to the downstream surface 1051a of the developing duct 1051, as shown in FIG. 22, so as to be elastically compressed in the insertion direction between the downstream surface 1051a of the developing duct 1051 and the upstream end 331a in the insertion direction of the first rail 331.

[0053] In order to efficiently cool the developing unit 24, it is desirable that the air passing through the developing duct 1051 passes through the path indicated by arrow R1 in FIG. 21 with almost no leakage into the cooling space 310. If the second seal member 202 of this embodiment were not provided, a gap might be formed between the developing duct 1051 and the upstream end 331a of the first rail 331 in the insertion direction, and the air passing through the developing duct 1051 would leak from the gap at one end in the width direction, as indicated by arrow R2 in FIG. 21. Therefore, by providing the second seal member 202, the air passing through the developing duct 1051 is passed through to the cooling space 310 with almost no leakage. Furthermore, the second seal member 202 is disposed so that a portion of the second seal member 202 overlaps with the first seal member 201 along the downstream surface 1051a in the width direction when viewed from the insertion direction of the developing unit 24. Furthermore, the second seal member 202 extends downstream from the step portion 1051b along the insertion direction of the developing unit 24. This is to allow the air whose leakage is suppressed by the first seal member 201 and the second seal member 202 to flow toward the cooling space 310.

[0054] As described above, a step portion 1051b is formed on the bottom surface of the developing duct 1051 (see FIG. 22). Therefore, if a single seal including the first seal member 201 and the second seal member 202 were attached to the bottom surface of the developing duct 1051, a small gap would be formed at the edge of the step portion 1051b, which could allow air to leak through the gap. Therefore, when attaching a single seal to the bottom surface of the developing duct 1051, it is necessary to prevent a gap from being formed at the edge of the step portion 1051b. However, this would result in a complex seal shape, which would be time-consuming to attach, and would also require an additional step to check that the seal is attached without any gaps. Therefore, in this embodiment, in consideration of the above points, the first seal member 201 and the second seal member 202 are attached to the bottom surface of the developing duct 1051 separately.

[0055] 22, the developing duct 1051 has a duct rib 1051d that protrudes downward from the downstream surface 1051a and extends in the insertion direction of the developing unit 24 at one end of the downstream surface 1051a on the second rail 332 side (second rail side) in the width direction. This duct rib 1051d prevents air from leaking from the opposite side of the exposure unit 4 in the width direction, in a gap that may occur between the downstream surface 1051a of the developing duct 1051 and the first surface 320a of the main body 330.

[0056] <Third sealing member> In this embodiment, as shown in Fig. 22, in addition to the first seal member 201 and second seal member 202 described above, a third seal member 203 is provided in the developing duct 1051. As shown in Fig. 22, the developing duct 1051 has a duct rib 212 extending along the insertion direction of the developing unit 24, outboard of the second seal member 202 in the width direction, and the third seal member 203 is attached to a downstream end 212a of the duct rib 212. As shown in Fig. 23, the main body 330 of the developer support tray 301 is provided with a tray rib 213 extending in the insertion direction so as to overlap with the downstream end 212a of the duct rib 212 of the developing duct 1051 when viewed from the insertion direction of the developing unit 24. With the developing unit 24 attached, the third seal member 203 seals between the downstream end 212a of the duct rib 212 of the developing duct 1051 and the upstream end 213a in the insertion direction of the tray rib 213 of the main body 330. As described above, the third seal member 203 is attached to the downstream end 212a of the duct rib 212 so as to be elastically compressed in the insertion direction between the downstream end 212a of the duct rib 212 and the upstream end 213a of the tray rib 213 in the insertion direction.

[0057] As described above, in order to efficiently cool the developing unit 24, it is desirable that the air that has passed through the developing duct 1051 passes through the path indicated by arrow R1 in FIG. 23 with almost no leakage into the cooling space 310. If the third seal member 203 of this embodiment were not provided, a gap might be formed between the developing duct 1051 and the upstream end 213a of the tray rib 213 in the insertion direction, and the air that has passed through the developing duct 1051 could leak from one end in the width direction through that gap, as indicated by arrow R3 in FIG. 23. Therefore, by providing the third seal member 203, the air that has passed through the developing duct 1051 is passed through to the cooling space 310 with almost no leakage.

[0058] <Other sealing materials> The above-described first seal member 201, second seal member 202, and third seal member 203 are all provided in the developing duct 1051. In this embodiment, in addition to these three seal members, a fourth seal member 204, a fifth seal member 205, a sixth seal member 206, and a seventh seal member 207 are provided in the developing device support tray 301 (more specifically, the main body portion 330).

[0059] 24, a fourth seal member 204, a sixth seal member 206, and a seventh seal member 207 are provided on the upper surface of the bottom of main body 330. Furthermore, as shown in Fig. 25, a fifth seal member 205 is provided on the lower surface of the bottom of main body 330. These fourth seal member 204, fifth seal member 205, sixth seal member 206, and seventh seal member 207 are provided to prevent air passing through cooling space 310 from leaking through holes or gaps formed in the bottom of main body 330.

[0060] As shown in Figures 24 and 26, the developing unit 24 is provided with a shutter 111 that can open and close an opening formed in the bottom of the developing container in order to discharge used toner to the outside of the developing container. When the shutter 111 is opened, the toner is discharged from the developing container, and the discharged toner falls by gravity to be collected in a toner recovery container (not shown). A fourth seal member 204 surrounds the opening of the developing container and seals the gap between the toner recovery container and the upper surface of the bottom of the main body 330. This prevents toner discharged from the opening of the developing container from scattering inside the apparatus main body 100A.

[0061] As described above, in this embodiment, the first seal member 201 is disposed in the gap between the bottom surface of the developing duct 1051 and the upper surface of the developing support tray 301. The first seal member 201 is elastically compressed in the vertical direction between the bottom surface of the developing duct 1051 and the upper surface of the developing support tray 301 to seal the gap, thereby preventing some of the air that has passed through the developing duct 1051 from flowing into the apparatus main body 100A. The first seal member 201 seals the entire gap in the width direction, preventing some of the air that has passed through the developing duct 1051 from flowing into the apparatus main body 100A from the upstream side in the insertion direction or both ends in the width direction. In addition, a second seal member 202 is disposed on the bottom surface of the developing duct 1051 downstream of the first seal member 201 in the insertion direction of the developing unit 24. The second seal member 202 is elastically compressed in the insertion direction between the development duct 1051 and the first rail 331, thereby sealing the gap between the development duct 1051 and the first rail 331 and preventing some of the air that has passed through the development duct 1051 from flowing into the apparatus main body 100A. The first rail 331 is a rail that is disposed on the exposure unit 4 side of the developer support tray 301, and the second seal member 202 seals the gap on the exposure unit 4 side, thereby preventing some of the air that has passed through the development duct 1051 from flowing toward the exposure unit 4. This prevents a decrease in the cooling efficiency of the development unit 24 and prevents air from flowing from the development duct 1051 toward the exposure unit 4 without passing through the cooling space 310. This prevents toner from adhering to the exposure unit 4 due to toner scattering that may occur due to air leaking from the gap between the development duct 1051 and the developer support tray 301. [Explanation of symbols]

[0062] 2...photosensitive member (photosensitive drum), 4...exposure section (exposure unit), 24...developing device (developing unit), 51...light-emitting element, 52...lens array, 100...image forming apparatus, 100A...apparatus main body, 201...first seal member, 202...second seal member, 301...support section (developing support tray), 310...space (cooling space), 320c...second surface (second surface), 330...main body, 331...first rail, 332...second rail, 1051...developing duct, 1051b...step portion, 1051c...first surface (upstream surface), 1051d...rib (duct rib), S...recording material (sheet)

Claims

1. An image forming apparatus, A device body, A photoreceptor; an exposure unit that exposes the surface of the photoreceptor to light and forms an electrostatic latent image; the exposure unit includes a plurality of light-emitting elements that are arranged adjacent to the photoreceptor and that emit light and are arranged in a line in the longitudinal direction of the photoreceptor, and a lens array that includes a plurality of lenses that focus the light emitted from the light-emitting elements onto the surface of the photoreceptor; a developing device that is detachable from the apparatus main body, that is disposed adjacent to the exposure unit in a width direction intersecting the longitudinal direction when attached to the apparatus main body, and that develops the electrostatic latent image on the photosensitive member into a toner image; a support portion that supports the developing device so that the developing device can be inserted and removed along the longitudinal direction when the developing device is attached to or detached from the device main body, the support portion having a main body portion and a first rail and a second rail provided along the longitudinal direction on a surface of the main body portion facing the developing device; a duct provided in the developing device, the duct allowing air to flow from an upstream side of the developing device in a direction in which the developing device is inserted into a space surrounded by the developing device, the main body portion, the first rail, and the second rail when the developing device is attached to the device main body; a first seal member that seals between a first surface of the duct on the main body side and a second surface of the main body that is located upstream of upstream ends of the first rail and the second rail in the insertion direction when the developing device is attached to the device main body; a second seal member that is provided downstream of the first seal member in the insertion direction and that seals between the first surface and an upstream end of the first rail in the insertion direction, the upstream end being located on the exposure unit side of the first rail and the second rail in the width direction when the developing device is attached to the device main body; An image forming apparatus characterized by:

2. the first seal member is elastically compressed in a vertical direction between the first surface of the duct and the second surface of the main body portion, the second seal member is elastically compressed in the insertion direction between the first surface of the duct and the upstream end of the first rail in the insertion direction.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. the duct has a step portion that divides the first surface into an upstream surface in the insertion direction and a downstream surface in the insertion direction, the first seal member is attached to a surface on the upstream side in the insertion direction, The second seal member is attached to a surface on the downstream side in the insertion direction.

3. The image forming apparatus according to claim 2, wherein the image forming apparatus is a recording medium.

4. When viewed from the insertion direction, a part of the second seal in the width direction overlaps with the first seal.

4. The image forming apparatus according to claim 3, wherein the image forming apparatus is a recording medium.

5. the duct has a rib that protrudes downward from the first surface and extends in the insertion direction, on the second rail side of the first surface in the width direction; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images